FLAME RETARDANT POLYCARBONATE COMPOSITIONS, METHODS OF MANUFACTURE THEREOF AND ARTICLES COMPRISING THE SAME
Disclosed herein is a flame retardant composition comprising 20 to 90 weight percent of a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on a total weight of the flame retardant composition. Disclosed herein too is a flame retardant composition comprising 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer; 0.5 to 10 weight percent of a silicone oil; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on the total weight of the flame retardant composition; where the composition displays a flame retardancy of 5VA at a thickness of 2.0 millimeters or greater; when tested as per a UL-94 protocol.
This application claims priority to U.S. Provisional Application No. 61/651,487 filed on May 24, 2012, and to U.S. Provisional Application No. 61/651,481 filed on May 24, 2012, the entire contents of both being hereby incorporated by reference.
BACKGROUNDThis disclosure relates to flame retardant polycarbonate compositions, methods of manufacture thereof and to articles comprising the same.
In electronic and electrical devices such as notebook personal computers, e-books, and tablet personal computers, metallic body panels are being replaced by materials that are lighter in weight and offer a robust combination of mechanical properties. These lighter materials result in weight savings, cost savings, and enable the manufacture of complex designs. While these lighter materials can be used to manufacture panels having thinner cross-sectional thicknesses, it is desirable to improve the stiffness of the material to prevent warping. It is also desirable to improve the flame retardancy of the material to reduce fire related hazards.
SUMMARYDisclosed herein is a flame retardant composition comprising 20 to 90 weight percent of a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on a total weight of the flame retardant composition.
Disclosed herein too is a method comprising blending 20 to 90 weight percent of a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on a total weight of the flame retardant composition; and extruding the flame retardant composition.
Disclosed herein is a flame retardant composition comprising 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer; 0.5 to 10 weight percent of a silicone oil; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on the total weight of the flame retardant composition; where the composition displays a flame retardancy of 5VA at a thickness of 2.0 millimeters or greater; when tested as per a UL-94 protocol.
Disclosed herein too is a method of manufacturing a flame retardancy composition comprising blending 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer; 0.5 to 10 weight percent of a silicone oil; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on the total weight of the flame retardant composition; where the composition displays a flame retardancy of 5VA at a thickness of 2.0 millimeters or greater; when tested as per a UL-94 protocol; and extruding the composition.
DETAILED DESCRIPTIONDisclosed herein is a flame retardant composition that displays a suitable combination of stiffness and ductility as well as a low melt viscosity that renders it easily processable. In one embodiment, the flame retardant composition comprises a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and a phosphazene compound. The polycarbonate composition may also comprise a high heat copolycarbonate derived from dihydroxy compounds such as 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one), 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane), or 1,1-bis((4-hydroxyphenyl)-3,3,5-trimethylcyclohexane).
Disclosed herein too is a method of manufacturing a flame retardant composition comprising blending a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and a phosphazene compound.
In another embodiment, the flame retardant composition comprises 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer; 0.5 to 10 weight percent of a silicone oil; and 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on the total weight of the flame retardant composition. The flame retardant composition displays a flame retardancy of 5VA at a thickness of 2.0 millimeters or greater; when tested as per a UL-94 protocol.
The method of manufacturing the flame retardant composition comprises blending the polycarbonate composition; the silicone oil; and the phosphazene compound and extruding and molding the flame retardant composition.
The term “polycarbonate composition”, “polycarbonate” and “polycarbonate resin” mean compositions having repeating structural carbonate units of the formula (1):
wherein at least 60 percent of the total number of R1 groups may contain aromatic organic groups and the balance thereof are aliphatic or alicyclic, or aromatic groups. R1 in the carbonate units of formula (1) may be a C6-C36 aromatic group wherein at least one moiety is aromatic. Each R1 may be an aromatic organic group, for example, a group of the formula (2):
-A1-Y1-A2- (2)
wherein each of the A1 and A2 is a monocyclic divalent aryl group and Y1 is a bridging group having one or two atoms that separate A1 and A2. For example, one atom may separate A1 from A2, with illustrative examples of these groups including —O—, —S—, —S(O)—, —S(O)2)—, —C(O)—, methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecyclidene, cyclododecylidene, and adamantylidene. The bridging group of Y1 may be a hydrocarbon group or a saturated hydrocarbon group such as methylene, cyclohexylidene, or isopropylidene.
The polycarbonates may be produced from dihydroxy compounds having the formula HO—R1—OH, wherein R1 is defined as above for formula (1). The formula HO—R1—OH includes bisphenol compounds of the formula (3):
HO-A1-Y1-A2-OH (3)
wherein Y1, A1, and A2 are as described above. For example, one atom may separate A1 and A2. Each R1 may include bisphenol compounds of the general formula (4):
where Xa is a bridging group connecting the two hydroxy-substituted aromatic groups, where the bridging group and the hydroxy substituent of each C6 arylene group are disposed ortho, meta, or para (specifically para) to each other on the C6 arylene group. For example, the bridging group Xa may be single bond, —O—, —S—, —C(O)—, or a C1-18 organic group. The C1-18 organic bridging group may be cyclic or acyclic, aromatic or non-aromatic, and can further comprise heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. The C1-18 organic group can be disposed such that the C6 arylene groups connected thereto are each connected to a common alkylidene carbon or to different carbons of the C1-18 organic bridging group. Ra and Rb may each represent a halogen, C1-12 alkyl group, or a combination thereof. For example, Ra and Rb may each be a C1-3 alkyl group, specifically methyl, disposed meta to the hydroxy group on each arylene group. The designation (e) is 0 or 1. The numbers p and q are each independently integers of 0 to 4. It will be understood that when p or q is less than 4, any available carbon valences are filled by hydrogen.
Xa may be substituted or unsubstituted C3-18 cycloalkylidene, a C1-25 alkylidene of formula —C(Rc)(Rd)— wherein Rc and Rd are each independently hydrogen, C1-12 alkyl, C1-12 cycloalkyl, C7-12 arylalkyl, C1-12 heteroalkyl, or cyclic C7-12 heteroarylalkyl, or a group of the formula —C(═Re)— wherein Re is a divalent C1-12 hydrocarbon group. This may include methylene, cyclohexylmethylene, ethylidene, neopentylidene, isopropylidene, 2-[2.2.1]-bicycloheptylidene, cyclohexylidene, cyclopentylidene, cyclododecylidene, and adamantylidene. A specific example wherein Xa is a substituted cycloalkylidene is the cyclohexylidene-bridged, alkyl-substituted bisphenol of formula (5):
wherein Ra′ and Rb′ are each independently C1-12 alkyl, Rg is C1-12 alkyl or halogen, r and s are each independently 1 to 4, and t is 0 to 10. Ra′ and Rb′ may be disposed meta to the cyclohexylidene bridging group. The substituents Ra′, Rb′ and Rg may, when comprising an appropriate number of carbon atoms, be straight chain, cyclic, bicyclic, branched, saturated, or unsaturated. For example, Rg may be each independently C1-4 alkyl, Rg is C1-4 alkyl, r and s are each 1, and t is 0 to 5. In another example, Ra′, Rb′ and Rg may each be methyl, r and s are each 1, and t is 0 or 3. The cyclohexylidene-bridged bisphenol can be the reaction product of two moles of o-cresol with one mole of cyclohexanone. In another example, the cyclohexylidene-bridged bisphenol may be the reaction product of two moles of a cresol with one mole of a hydrogenated isophorone (e.g., 1,1,3-trimethyl-3-cyclohexane-5-one). Such cyclohexane-containing bisphenols, for example the reaction product of two moles of a phenol with one mole of a hydrogenated isophorone, are useful for making polycarbonate polymers with high glass transition temperatures and high heat distortion temperatures. Cyclohexyl bisphenol-containing polycarbonates, or a combination comprising at least one of the foregoing with other bisphenol polycarbonates, are supplied by Bayer Co. under the APEC® trade name.
In an embodiment, Xa is a C1-18 alkylene group, a C3-18 cycloalkylene group, a fused C6-18 cycloalkylene group, or a group of the formula —B1—W—B2— wherein B1 and B2 are the same or different C1-6alkylene group and W is a C3-12 cycloalkylidene group or a C6-16 arylene group.
In another example, Xa may be a substituted C3-18 cycloalkylidene of the formula (6):
wherein Rr, Rp, Rq, and Rt are independently hydrogen, halogen, oxygen, or C1-12 organic groups; I is a direct bond, a carbon, or a divalent oxygen, sulfur, or —N(Z)— where Z is hydrogen, halogen, hydroxy, C1-12 alkyl, C1-12 alkoxy, C6-12 aryl, or C1-12 acyl; h is 0 to 2, j is 1 or 2, i is an integer of 0 or 1, and k is an integer of 0 to 3, with the proviso that at least two of Rr, Rp, Rq and Rt taken together are a fused cycloaliphatic, aromatic, or heteroaromatic ring. It will be understood that where the fused ring is aromatic, the ring as shown in formula (5) will have an unsaturated carbon-carbon linkage at the junction where the ring is fused. When i is 0, h is 0, and k is 1, the ring as shown in formula (5) contains 4 carbon atoms; when i is 0, h is 0, and k is 2, the ring as shown contains 5 carbon atoms, and when i is 0, h is 0, and k is 3, the ring contains 6 carbon atoms. In one example, two adjacent groups (e.g., Rq and Rt taken together) form an aromatic group, and in another embodiment, Rq and Rt taken together form one aromatic group and Rr and Rp taken together form a second aromatic group. When Rq and Rt taken together form an aromatic group, Rp can be a double-bonded oxygen atom, i.e., a ketone.
Other useful dihydroxy compounds having the formula HO—R1—OH include aromatic dihydroxy compounds of formula (7):
wherein each Rh is independently a halogen atom, a C1-10 hydrocarbyl such as a C1-10 alkyl group, a halogen substituted C1-10 hydrocarbyl such as a halogen-substituted C1-10 alkyl group, and n is 0 to 4. The halogen is usually bromine.
Bisphenol-type dihydroxy aromatic compounds may include the following: 4,4′-dihydroxybiphenyl, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxy-3 methyl phenyl)cyclohexane 1,1-bis(4-hydroxyphenyl)isobutene, 1,1-bis(4-hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4-hydroxyphenyl)adamantine, (alpha,alpha′-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene, 4,4′-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone, 1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorene, 2,7-dihydroxypyrene, 6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindane bisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine, 3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole, and the like, as well as a combination comprising at least one of the foregoing dihydroxy aromatic compounds.
Examples of the types of bisphenol compounds represented by formula (3) may include 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (hereinafter “bisphenol A” or “BPA”), 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, 1,1-bis(4-hydroxy-t-butylphenyl)propane, 3,3-bis(4-hydroxyphenyl)phthalimidine, 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (“PBPP”), 9,9-bis(4-hydroxyphenyl)fluorene, and 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (“DMBPC”). Combinations comprising at least one of the foregoing dihydroxy aromatic compounds can also be used.
The dihydroxy compounds of formula (3) may exist in the form of the following formula (8):
wherein R3 and R5 are each independently a halogen or a C1-6 alkyl group, R4 is a C1-6 alkyl, phenyl, or phenyl substituted with up to five halogens or C1-6 alkyl groups, and c is 0 to 4. In a specific embodiment, R4 is a C1-6 alkyl or phenyl group. In still another embodiment, R4 is a methyl or phenyl group. In another specific embodiment, each c is 0.
The dihydroxy compounds of formula (3) may be the following formula (9):
(also known as 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP)).
Alternatively, the dihydroxy compounds of formula (3) may have the following formula (10):
(also known as 4,4′-(1-phenylethane-1,1-diyl)diphenol (bisphenol AP) or 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane).
Alternatively, the dihydroxy compounds of formula (3) may have the following formula (11):
which is also known as 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, or 4,4′-(3,3,5-trimethylcyclohexane-1,1-diyl)diphenol (bisphenol TMC). When a copolycarbonate comprising polycarbonates derived from the formulas (9), (10) and (11) is used in the flame retardant compositions, it is generally used in amounts of 2 to 30 wt %, specifically 3 to 25 wt %, and more specifically 4 to 20 wt %, based on the total weight of the flame retardant composition.
Exemplary copolymers containing polycarbonate units may be derived from bisphenol A. In one embodiment, the polycarbonate composition may comprise a polyester-polycarbonate copolymer. A specific type of copolymer may be a polyestercarbonate, also known as a polyester-polycarbonate. As used herein, these terms (i.e., the polyestercarbonate and the polyester-polycarbonate) are synonymous. Such copolymers further contain, in addition to recurring carbonate chain units of the formula (1) as described above, repeating ester units of formula (12):
wherein O-D-O is a divalent group derived from a dihydroxy compound, and D may be, for example, one or more alkyl containing C6-C20 aromatic group(s), or one or more C6-C20 aromatic group(s), a C2-10 alkylene group, a C6-20 alicyclic group, a C6-20 aromatic group or a polyoxyalkylene group in which the alkylene groups contain 2 to 6 carbon atoms, specifically 2, 3, or 4 carbon atoms. D may be a C2-30 alkylene group having a straight chain, branched chain, or cyclic (including polycyclic) structure. O-D-O may be derived from an aromatic dihydroxy compound of formula (3) above. O-D-O may be derived from an aromatic dihydroxy compound of formula (4) above. O-D-O may be derived from an aromatic dihydroxy compound of formula (7) above.
The molar ratio of ester units to carbonate units in the copolymers may vary broadly, for example 1:99 to 99:1, specifically 10:90 to 90:10, and more specifically 25:75 to 75:25, depending on the desired properties of the final composition.
T of formula (12) may be a divalent group derived from a dicarboxylic acid, and may be, for example, a C2-10 alkylene group, a C6-20 alicyclic group, a C6-20 alkyl aromatic group, a C6-20 aromatic group, or a C6 to C36 divalent organic group derived from a dihydroxy compound or chemical equivalent thereof. In an embodiment, T is an aliphatic group. T may be derived from a C6-C20 linear aliphatic alpha-omega (αΩ) dicarboxylic ester.
Diacids from which the T group in the ester unit of formula (12) is derived include aliphatic dicarboxylic acid from 6 to 36 carbon atoms, optionally from 6 to 20 carbon atoms. The C6-C20 linear aliphatic alpha-omega (αΩ) dicarboxylic esters may be derived from adipic acid, sebacic acid, 3,3-dimethyl adipic acid, 3,3,6-trimethyl sebacic acid, 3,3,5,5-tetramethyl sebacic acid, azelaic acid, dodecanedioic acid, dimer acids, cyclohexane dicarboxylic acids, dimethyl cyclohexane dicarboxylic acid, norbornane dicarboxylic acids, adamantane dicarboxylic acids, cyclohexene dicarboxylic acids, C14, C18 and C20 diacids.
In an embodiment, aliphatic alpha-omega dicarboxylic acids that may be reacted with a bisphenol to form a polyester include adipic acid, sebacic acid or dodecanedioic acid. Sebacic acid is a dicarboxylic acid having the following formula (13):
Sebacic acid has a molecular mass of 202.25 g/mol, a density of 1.209 g/cm3 (25° C.), and a melting point of 294.4° C. at 100 mm Hg. Sebacic acid may be derived from castor oil.
Other examples of aromatic dicarboxylic acids that may be used to prepare the polyester units include isophthalic or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether, 4,4′-bisbenzoic acid, and combinations comprising at least one of the foregoing acids. Acids containing fused rings can also be present, such as in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specific dicarboxylic acids may be terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, sebacic acid, or combinations thereof.
Mixtures of the diacids can also be employed. It should be noted that although referred to as diacids, any ester precursor could be employed such as acid halides, specifically acid chlorides, and diaromatic esters of the diacid such as diphenyl, for example, the diphenylester of sebacic acid. The diacid carbon atom number does not include any carbon atoms that may be included in the ester precursor portion, for example diphenyl. It may be desirable that at least four, five, or six carbon bonds separate the acid groups. This may reduce the formation of undesirable and unwanted cyclic species. The aromatic dicarboxylic acids may be used in combination with the saturated aliphatic alpha-omega dicarboxylic acids to yield the polyester. In an exemplary embodiment, isophthalic acid or terephthalic acid may be used in combination with the sebacic acid to produce the polyester.
Overall, D of the polyester-polycarbonate may be a C2-9 alkylene group and T is p-phenylene, m-phenylene, naphthalene, a divalent cycloaliphatic group, or a combination thereof. This class of polyester includes the poly(alkylene terephthalates).
The polyester-polycarbonate may have a bio-content (i.e., a sebacic acid content) according to ASTM-D-6866 of 2 weight percent (wt %) to 65 wt %, based on the total weight of the polycarbonate composition. In an embodiment, the polyester-polycarbonate may have a bio-content according to ASTM-D-6866 of at least 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt %, 10 wt %, 11 wt %, 12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %, 20 wt %, 25 wt %, 30 wt %, 35 wt %, 40 wt %, 45 wt %, 50 wt %, 55 wt %, 60 wt % or 65 wt % of the composition derived therefrom. The polyester-polycarbonate may have a bio-content according to ASTM-D-6866 of at least 5 wt % of the polycarbonate composition. In other words, the polycarbonate composition may have at least 5 wt % of sebacic acid.
In an embodiment, two polycarbonate copolymers may be used in the flame retardant composition. The first polycarbonate copolymer comprises a polyester derived from sebacic acid that is copolymerized with a polycarbonate. The first polycarbonate polymer is endcapped with phenol or t-butyl-phenol. The second polycarbonate copolymer also comprises polyester units derived from sebacic acid that is copolymerized with a polycarbonate. The second polycarbonate copolymer is endcapped with para-cumyl phenol (PCP). The first polycarbonate has a lower molecular weight than the second polycarbonate copolymer.
The first polycarbonate copolymer has a weight average molecular weight of 15,000 to 28,000 Daltons, specifically 17,000 to 25,500 Daltons, specifically 19,000 to 23,000 Daltons, and more specifically 20,000 to 22,000 Daltons as measured by gel permeation chromatography using a polycarbonate standard. The first polycarbonate copolymer may comprise 3.0 mole % to 8.0 mole %, specifically 4.0 mole % to 7.5 mole %, and more specifically 5.0 mole % to 6.5 mole % of the polyester derived from sebacic acid.
The first polycarbonate copolymer is used in amounts of 10 to 60 wt %, specifically 15 to 58 wt %, specifically 20 to 55 wt %, and more specifically 23 to 52 wt %, based on the total weight of the flame retardant composition. In an exemplary embodiment, the first polycarbonate copolymer was present in an amount of 35 to 55 wt %, based on the total weight of the flame retardant composition.
In an embodiment, the second polycarbonate copolymer is endcapped with para-cumyl phenol and has a weight average molecular weight of 30,000 to 45,000 Daltons, specifically 32,000 to 40,000 Daltons, specifically 34,000 to 39,000 Daltons, more specifically 35,000 to 38,000 Daltons as measured by gel permeation chromatography using a polycarbonate standard. The second polycarbonate copolymer may comprise 7 mole % to 12 mole %, specifically 7.5 mole % to 10 mole %, and more specifically 8.0 mole % to 9.0 mole % of polyester derived from sebacic acid.
The second polycarbonate copolymer is used in amounts of 10 to 35 wt %, specifically 12 to 60 wt %, specifically 13 to 58 wt %, specifically 14 to 57 wt %, and more specifically 15 to 55 wt %, based on the total weight of the flame retardant composition.
Overall, the first and the second polycarbonate copolymers may contain 1 to 15 wt %, specifically 2 to 12 wt %, specifically 3 to 10 wt %, specifically 4 to 9 wt %, and more specifically 5 to 8 wt % of the polyester derived from sebacic acid. The polyester-polycarbonate copolymer may comprise 1.0 wt %, 2.0 wt %, 3.0 wt %, 4.0 wt %, 5.0 wt %, 6.0 wt %, 7.0 wt %, 8.0 wt %, 9.0 wt %, 10.0 wt %, 11.0 wt %, 12.0 wt %, 13.0 wt %, 14.0 wt %, and 15.0 wt % of a polyester derived from sebacic acid.
In one form, the first and second polycarbonate copolymers are polyester-polycarbonate copolymers where the polyester is derived by reacting by reacting sebacic acid with bisphenol A and where the polycarbonate is obtained from the reaction of bisphenol A with phosgene. The first and second polycarbonate copolymers containing the polyester-polycarbonate copolymer has the following formula (14):
Formula (14) may be designed to be a high flow ductile (HFD) polyester-polycarbonate copolymer (HFD). The high flow ductile copolymer has low molecular (LM) weight polyester units derived from sebacic acid. The polyester derived from sebacic acid in the high flow ductile copolymer is present in an amount of 6.0 mole % to 8.5 mole %. In an embodiment, the polyester derived from sebacic acid has a weight average molecular weight of 21,000 to 36,500 Daltons. In an exemplary embodiment, the high flow ductile polyester-polycarbonate copolymer may have a weight average molecular weight average of 21,500 Daltons as measured by gel permeation chromatography using a polycarbonate standard. It is desirable for the high flow ductile polyester-polycarbonate copolymer to contain 6.0 mole % derived from sebacic acid.
The first and the second polycarbonate copolymer which comprises the polyester-polycarbonate copolymers beneficially have a low level of carboxylic anhydride groups. Anhydride groups are where two aliphatic diacids, or chemical equivalents, react to form an anhydride linkage. The amount of carboxylic acid groups bound in such anhydride linkages should be less than or equal to 10 mole % of the total amount of carboxylic acid content in the copolymer. In other embodiments, the anhydride content should be less than or equal to 5 mole % of carboxylic acid content in the copolymer, and in yet other embodiments, the carboxylic acid content in the copolymer should be less than or equal to 2 mole %.
Low levels of anhydride groups can be achieved by conducting an interfacial polymerization reaction of the dicarboxylic acid, bisphenol and phosgene initially at a low pH (4 to 6) to get a high incorporation of the diacid in the polymer, and then after a proportion of the monomer has been incorporated into the growing polymer chain, switching to a high pH (10 to 11) to convert any anhydride groups into ester linkages. Anhydride linkages can be determined by numerous methods such as, for instance proton NMR analyses showing signal for the hydrogens adjacent to the carbonyl group. In an embodiment, the first and the second polycarbonate copolymer have a low amount of anhydride linkages, such as, for example, less than or equal to 5 mole %, specifically less than or equal to 3 mole %, and more specifically less than or equal to 2 mole %, as determined by proton NMR analysis. Low amounts of anhydride linkages in the polyester-polycarbonate copolymer contribute to superior melt stability in the copolymer, as well as other desirable properties.
Useful polyesters that can be copolymerized with polycarbonate can include aromatic polyesters, poly(alkylene esters) including poly(alkylene arylates), and poly(cycloalkylene diesters). Aromatic polyesters can have a polyester structure according to formula (12), wherein D and T are each aromatic groups as described hereinabove. In an embodiment, useful aromatic polyesters can include, for example, poly(isophthalate-terephthalate-resorcinol) esters, poly(isophthalate-terephthalate-bisphenol A) esters, poly[(isophthalate-terephthalate-resorcinol) ester-co-(isophthalate-terephthalate-bisphenol A)]ester, or a combination comprising at least one of these. Also contemplated are aromatic polyesters with a minor amount, e.g., 0.5 to 10 weight percent, based on the total weight of the polyester, of units derived from an aliphatic diacid and/or an aliphatic polyol to make copolyesters. Poly(alkylene arylates) can have a polyester structure according to formula (12), wherein T comprises groups derived from aromatic dicarboxylates, cycloaliphatic dicarboxylic acids, or derivatives thereof. Examples of specifically useful T groups include 1,2-, 1,3-, and 1,4-phenylene; 1,4- and 1,5-naphthylenes; cis- or trans-1,4-cyclohexylene; and the like. Specifically, where T is 1,4-phenylene, the poly(alkylene arylate) is a poly(alkylene terephthalate). In addition, for poly(alkylene arylate), specifically useful alkylene groups D include, for example, ethylene, 1,4-butylene, and bis-(alkylene-disubstituted cyclohexane) including cis- and/or trans-1,4-(cyclohexylene)dimethylene. Examples of poly(alkylene terephthalates) include poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), and polypropylene terephthalate) (PPT). Also useful are poly(alkylene naphthoates), such as poly(ethylene naphthanoate) (PEN), and poly(butylene naphthanoate) (PBN). A specifically useful poly(cycloalkylene diester) is poly(cyclohexanedimethylene terephthalate) (PCT). Combinations comprising at least one of the foregoing polyesters can also be used.
Copolymers comprising alkylene terephthalate repeating ester units with other ester groups can also be useful. Specifically useful ester units can include different alkylene terephthalate units, which can be present in the polymer chain as individual units, or as blocks of poly(alkylene terephthalates). Copolymers of this type include poly(cyclohexanedimethylene terephthalate)-co-poly(ethylene terephthalate), abbreviated as PETG where the polymer comprises greater than or equal to 50 mol % of poly(ethylene terephthalate), and abbreviated as PCTG where the polymer comprises greater than 50 mol % of poly(1,4-cyclohexanedimethylene terephthalate).
Poly(cycloalkylene diester)s can also include poly(alkylene cyclohexanedicarboxylate)s. Of these, a specific example is poly(1,4-cyclohexane-dimethanol-1,4-cyclohexanedicarboxylate) (PCCD), having recurring units of formula (14a)
wherein, as described using formula (12), D is a 1,4-cyclohexanedimethylene group derived from 1,4-cyclohexanedimethanol, and T is a cyclohexane ring derived from cyclohexanedicarboxylate or a chemical equivalent thereof, and can comprise the cis-isomer, the trans-isomer, or a combination comprising at least one of the foregoing isomers.
The polycarbonate and polyester can be used in a weight ratio of 1:99 to 99:1, specifically 10:90 to 90:10, and more specifically 30:70 to 70:30, depending on the function and properties desired.
It is desirable for such a polyester and polycarbonate blend to have an MVR of 5 to 150 cc/10 min., specifically 7 to 125 cc/10 min, more specifically 9 to 110 cc/10 min, and still more specifically 10 to 100 cc/10 min., measured at 300° C. and a load of 1.2 kilograms according to ASTM D1238-04.
In an exemplary embodiment, the polycarbonate composition comprises a copolyestercarbonate comprising poly(1,4-cyclohexane-dimethanol-1,4-cyclohexanedicarboxylate) (PCCD). The copolyestercarbonate is present in an amount of 5 to 25 wt %, specifically 6 to 15 wt %, and more specifically 7 to 12 wt %, based on the total weight of the flame retardant composition.
Polycarbonates may be manufactured by processes such as interfacial polymerization and melt polymerization. Copolycarbonates having a high glass transition temperature are generally manufactured using interfacial polymerization. Although the reaction conditions for interfacial polymerization can vary, an exemplary process generally involves dissolving or dispersing a dihydric phenol reactant in aqueous caustic soda or potash, adding the resulting mixture to a water-immiscible solvent medium, and contacting the reactants with a carbonate precursor in the presence of a catalyst such as, for example, a tertiary amine or a phase transfer catalyst, under controlled pH conditions, e.g., 8 to 10. The most commonly used water immiscible solvents include methylene chloride, 1,2-dichloroethane, chlorobenzene, toluene, and the like.
Exemplary carbonate precursors may include, for example, a carbonyl halide such as carbonyl bromide or carbonyl chloride, or a haloformate such as a bishaloformates of a dihydric phenol (e.g., the bischloroformates of bisphenol A, hydroquinone, or the like) or a glycol (e.g., the bishaloformate of ethylene glycol, neopentyl glycol, polyethylene glycol, or the like). Combinations comprising at least one of the foregoing types of carbonate precursors can also be used. For example, an interfacial polymerization reaction to form carbonate linkages uses phosgene as a carbonate precursor, and is referred to as a phosgenation reaction.
Among tertiary amines that can be used are aliphatic tertiary amines such as triethylamine, tributylamine, cycloaliphatic amines such as N,N-diethyl-cyclohexylamine, and aromatic tertiary amines such as N,N-dimethylaniline.
Among the phase transfer catalysts that can be used are catalysts of the formula (R3)4Q+X, wherein each R3 is the same or different, and is a C1-10 alkyl group; Q is a nitrogen or phosphorus atom; and X is a halogen atom or a C1-8 alkoxy group or C6-18 aryloxy group. Exemplary phase transfer catalysts include, for example, [CH3(CH2)3]4NX, [CH3(CH2)3]4PX, [CH3(CH2)5]4NX, [CH3(CH2)6]4NX, [CH3(CH2)4]4NX, CH3[CH3(CH2)3]3NX, and CH3[CH3(CH2)2]3NX, wherein X is Cl−, Br−, a C1-8 alkoxy group or a C6-18 aryloxy group. An effective amount of a phase transfer catalyst can be 0.1 to 10 wt % based on the weight of bisphenol in the phosgenation mixture. For example, an effective amount of phase transfer catalyst can be 0.5 to 2 wt % based on the weight of bisphenol in the phosgenation mixture.
Alternatively, melt processes can be used to make the polycarbonates. Melt polymerization may be conducted as a batch process or as a continuous process. In either case, the melt polymerization conditions used may comprise two or more distinct reaction stages, for example, a first reaction stage in which the starting dihydroxy aromatic compound and diaryl carbonate are converted into an oligomeric polycarbonate and a second reaction stage wherein the oligomeric polycarbonate formed in the first reaction stage is converted to high molecular weight polycarbonate. Such “staged” polymerization reaction conditions are especially suitable for use in continuous polymerization systems wherein the starting monomers are oligomerized in a first reaction vessel and the oligomeric polycarbonate formed therein is continuously transferred to one or more downstream reactors in which the oligomeric polycarbonate is converted to high molecular weight polycarbonate. Typically, in the oligomerization stage the oligomeric polycarbonate produced has a number average molecular weight of about 1,000 to about 7,500 Daltons. In one or more subsequent polymerization stages the number average molecular weight (Mn) of the polycarbonate is increased to between about 8,000 and about 25,000 Daltons (using polycarbonate standard).
The term “melt polymerization conditions” is understood to mean those conditions necessary to effect reaction between a dihydroxy aromatic compound and a diaryl carbonate in the presence of a transesterification catalyst. Typically, solvents are not used in the process, and the reactants dihydroxy aromatic compound and the diaryl carbonate are in a molten state. The reaction temperature can be about 100° C. to about 350° C., specifically about 180° C. to about 310° C. The pressure may be at atmospheric pressure, supra-atmospheric pressure, or a range of pressures from atmospheric pressure to about 15 torr in the initial stages of the reaction, and at a reduced pressure at later stages, for example about 0.2 to about 15 torr. The reaction time is generally about 0.1 hours to about 10 hours.
The diaryl carbonate ester can be diphenyl carbonate, or an activated diphenyl carbonate having electron-withdrawing substituents on the aryl groups, such as bis(4-nitrophenyl)carbonate, bis(2-chlorophenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate, bis(4-methylcarboxylphenyl)carbonate, bis(2-acetylphenyl)carboxylate, bis(4-acetylphenyl)carboxylate, or a combination comprising at least one of the foregoing.
Catalysts used in the melt polymerization of polycarbonates can include alpha or beta catalysts. Beta catalysts are typically volatile and degrade at elevated temperatures. Beta catalysts are therefore preferred for use at early low-temperature polymerization stages. Alpha catalysts are typically more thermally stable and less volatile than beta catalysts.
The alpha catalyst can comprise a source of alkali or alkaline earth ions. The sources of these ions include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, as well as alkaline earth hydroxides such as magnesium hydroxide and calcium hydroxide. Other possible sources of alkali and alkaline earth metal ions include the corresponding salts of carboxylic acids (such as sodium acetate) and derivatives of ethylene diamine tetraacetic acid (EDTA) (such as EDTA tetrasodium salt, and EDTA magnesium disodium salt). Other alpha transesterification catalysts include alkali or alkaline earth metal salts of a non-volatile inorganic acid such as NaH2PO3, NaH2PO4, Na2HPO3, KH2PO4, CsH2PO4, Cs2HPO4, and the like, or mixed salts of phosphoric acid, such as NaKHPO4, CsNaHPO4, CsKHPO4, and the like. Combinations comprising at least one of any of the foregoing catalysts can be used.
Possible beta catalysts can comprise a quaternary ammonium compound, a quaternary phosphonium compound, or a combination comprising at least one of the foregoing. The quaternary ammonium compound can be a compound of the structure (R4)4N+X−, wherein each R4 is the same or different, and is a C1-20 alkyl group, a C4-20 cycloalkyl group, or a C4-20 aryl group; and X−is an organic or inorganic anion, for example a hydroxide, halide, carboxylate, sulfonate, sulfate, formate, carbonate, or bicarbonate. Examples of organic quaternary ammonium compounds include tetramethyl ammonium hydroxide, tetrabutyl ammonium hydroxide, tetramethyl ammonium acetate, tetramethyl ammonium formate, tetrabutyl ammonium acetate, and combinations comprising at least one of the foregoing. Tetramethyl ammonium hydroxide is often used. The quaternary phosphonium compound can be a compound of the structure (R5)4P+X−, wherein each R5 is the same or different, and is a C1-20 alkyl group, a C4-20 cycloalkyl group, or a C4-20 aryl group; and X−is an organic or inorganic anion, for example a hydroxide, halide, carboxylate, sulfonate, sulfate, formate, carbonate, or bicarbonate. Where X−is a polyvalent anion such as carbonate or sulfate it is understood that the positive and negative charges in the quaternary ammonium and phosphonium structures are properly balanced. For example, where R20-R23 are each methyl groups and X−is carbonate, it is understood that X−represents 2(CO3−2). Examples of organic quaternary phosphonium compounds include tetramethyl phosphonium hydroxide, tetramethyl phosphonium acetate, tetramethyl phosphonium formate, tetrabutyl phosphonium hydroxide, tetrabutyl phosphonium acetate (TBPA), tetraphenyl phosphonium acetate, tetraphenyl phosphonium phenoxide, and combinations comprising at least one of the foregoing. TBPA is often used.
The amount of alpha and beta catalyst used can be based upon the total number of moles of dihydroxy compound used in the polymerization reaction. When referring to the ratio of beta catalyst, for example a phosphonium salt, to all dihydroxy compounds used in the polymerization reaction, it is convenient to refer to moles of phosphonium salt per mole of the dihydroxy compound, meaning the number of moles of phosphonium salt divided by the sum of the moles of each individual dihydroxy compound present in the reaction mixture. The alpha catalyst can be used in an amount sufficient to provide 1×10−2 to 1×10−8 moles, specifically, 1×10−4 to 1×10−7 moles of metal per mole of the dihydroxy compounds used. The amount of beta catalyst (e.g., organic ammonium or phosphonium salts) can be 1×10−2 to 1×10−5, specifically 1×10−3 to 1×10−4 moles per total mole of the dihydroxy compounds in the reaction mixture.
All types of polycarbonate end groups are contemplated as being useful in the high and low glass transition temperature polycarbonates, provided that such end groups do not significantly adversely affect desired properties of the compositions. An end-capping agent (also referred to as a chain-stopper) can be used to limit molecular weight growth rate, and so control molecular weight of the first and/or second polycarbonate. Exemplary chain-stoppers include certain monophenolic compounds (i.e., phenyl compounds having a single free hydroxy group), monocarboxylic acid chlorides, and/or monochloroformates. Phenolic chain-stoppers are exemplified by phenol and C1-C22 alkyl-substituted phenols such as para-cumyl-phenol, resorcinol monobenzoate, and p- and tertiary-butyl phenol, cresol, and monoethers of diphenols, such as p-methoxyphenol. Alkyl-substituted phenols with branched chain alkyl substituents having 8 to 9 carbon atoms can be specifically mentioned. In an embodiment, at least one of the copolymers is endcapped with para-cumyl phenol (PCP).
Endgroups can be derived from the carbonyl source (i.e., the diaryl carbonate), from selection of monomer ratios, incomplete polymerization, chain scission, and the like, as well as any added end-capping groups, and can include derivatizable functional groups such as hydroxy groups, carboxylic acid groups, or the like. In an embodiment, the endgroup of a polycarbonate can comprise a structural unit derived from a diaryl carbonate, where the structural unit can be an endgroup. In a further embodiment, the endgroup is derived from an activated carbonate. Such endgroups can derive from the transesterification reaction of the alkyl ester of an appropriately substituted activated carbonate, with a hydroxy group at the end of a polycarbonate polymer chain, under conditions in which the hydroxy group reacts with the ester carbonyl from the activated carbonate, instead of with the carbonate carbonyl of the activated carbonate. In this way, structural units derived from ester containing compounds or substructures derived from the activated carbonate and present in the melt polymerization reaction can form ester endgroups. In an embodiment, the ester endgroup derived from a salicylic ester can be a residue of BMSC or other substituted or unsubstituted bis(alkyl salicyl)carbonate such as bis(ethyl salicyl)carbonate, bis(propyl salicyl)carbonate, bis(phenyl salicyl)carbonate, bis(benzyl salicyl)carbonate, or the like. In a specific embodiment, where BMSC is used as the activated carbonyl source, the endgroup is derived from and is a residue of BMSC, and is an ester endgroup derived from a salicylic acid ester, having the structure of formula (15):
The reactants for the polymerization reaction using an activated aromatic carbonate can be charged into a reactor either in the solid form or in the molten form. Initial charging of reactants into a reactor and subsequent mixing of these materials under reactive conditions for polymerization may be conducted in an inert gas atmosphere such as a nitrogen atmosphere. The charging of one or more reactant may also be done at a later stage of the polymerization reaction. Mixing of the reaction mixture is accomplished by stirring or other forms of agitation. Reactive conditions include time, temperature, pressure and other factors that affect polymerization of the reactants. In an embodiment, the activated aromatic carbonate is added at a mole ratio of 0.8 to 1.3, and more specifically 0.9 to 1.3, and all sub-ranges there between, relative to the total moles of monomer unit compounds. In a specific embodiment, the molar ratio of activated aromatic carbonate to monomer unit compounds is 1.013 to 1.29, specifically 1.015 to 1.028. In another specific embodiment, the activated aromatic carbonate is BMSC.
Branched polycarbonate blocks can be prepared by adding a branching agent during polymerization. These branching agents include polyfunctional organic compounds containing at least three functional groups selected from hydroxyl, carboxyl, carboxylic anhydride, haloformyl, and mixtures of the foregoing functional groups. Specific examples include trimellitic acid, trimellitic anhydride, tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha,alpha-dimethyl benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid, and benzophenone tetracarboxylic acid. Combinations comprising linear polycarbonates and branched polycarbonates can be used.
In some embodiments, a particular type of branching agent is used to create branched polycarbonate materials. These branched polycarbonate materials have statistically more than two end groups. The branching agent is added in an amount (relative to the bisphenol monomer) that is sufficient to achieve the desired branching content, that is, more than two end groups. The molecular weight of the polymer may become very high upon addition of the branching agent, and to avoid excess viscosity during polymerization, an increased amount of a chain stopper agent can be used, relative to the amount used when the particular branching agent is not present. The amount of chain stopper used is generally above 5 mole percent and less than 20 mole percent compared to the bisphenol monomer.
Such branching agents include aromatic triacyl halides, for example triacyl chlorides of formula (16)
wherein Z is a halogen, C1-3 alkyl, C1-3 alkoxy, C7-12 arylalkylene, C7-12 alkylarylene, or nitro, and z is 0 to 3; a tri-substituted phenol of formula (17)
wherein T is a C1-20 alkyl, C1-20 alkyleneoxy, C7-12 arylalkyl, or C7-12 alkylaryl, Y is a halogen, C1-3 alkyl, C1-3 alkoxy, C7-12 arylalkyl, C7-12 alkylaryl, or nitro, s is 0 to 4; or a compound of formula (18) (isatin-bis-phenol).
Examples of specific branching agents that are particularly effective in the compositions include trimellitic trichloride (TMTC), tris-p-hydroxyphenylethane (THPE), and isatin-bis-phenol.
The amount of the branching agents used in the manufacture of the polymer will depend on a number of considerations, for example the type of R1 groups, the amount of chain stopper, e.g., cyanophenol, and the desired molecular weight of the polycarbonate. In general, the amount of branching agent is effective to provide about 0.1 to 10 branching units per 100 R1 units, specifically about 0.5 to 8 branching units per 100 R1 units, and more specifically about 0.75 to 5 branching units per 100 R1 units. For branching agents having formula (16), the branching agent triester groups are present in an amount of about 0.1 to 10 branching units per 100 R1 units, specifically about 0.5 to 8 branching units per 100 R1 units, and more specifically about 0.75 to 5 branching agent triester units per 100 R1 units. For branching agents having formula (17) or (18), the branching agent triphenyl carbonate groups formed are present in an amount of about 0.1 to 10 branching units per 100 R1 units, specifically about 0.5 to 8 branching units per 100 R1 units, and more specifically about 0.75 to 5 triphenylcarbonate units per 100 R1 units. In some embodiments, a combination of two or more branching agents may be used. Alternatively, the branching agents can be added at a level of about 0.05 to about 2.0 wt. %.
In an embodiment, the polycarbonate is a branched polycarbonate comprising units as described above; greater than or equal to 3 mole %, based on the total moles of the polycarbonate, of moieties derived from a branching agent; and end-capping groups derived from an end-capping agent having a pKa between about 8.3 and about 11. The branching agent can comprise trimellitic trichloride, 1,1,1-tris(4-hydroxyphenyl)ethane or a combination of trimellitic trichloride and 1,1,1-tris(4-hydroxyphenyl)ethane, and the end-capping agent is phenol or a phenol containing a substituent of cyano group, aliphatic groups, olefinic groups, aromatic groups, halogens, ester groups, ether groups, or a combination comprising at least one of the foregoing. In a specific embodiment, the end-capping agent is phenol, p-t-butylphenol, p-methoxyphenol, p-cyanophenol, p-cumylphenol, or a combination comprising at least one of the foregoing.
As noted above, the polycarbonate composition may include a linear polycarbonate, a branched polycarbonate, or a mixture of a linear and a branched polycarbonate. When the polycarbonate composition includes a mixture of a linear and a branched polycarbonate, the branched polycarbonate is used in amounts of 5 to 95 wt %, specifically 10 to 25 wt % and more specifically 12 to 20 wt %, based on the total weight of the polycarbonate composition. Linear polycarbonates are used in amounts of 5 to 95 wt %, specifically 20 to 60 wt %, and more specifically 25 to 55 wt %, based on the total weight of the polycarbonate composition.
In one embodiment, the polycarbonate composition comprises post-consumer recycle (PCR) polycarbonate derived from previously manufactured articles (e.g., soda bottles, water bottles, and the like) that comprise polycarbonate. The PCR materials occasionally comprise a polyester, which degrades the flame retardancy characteristics. The polyester present in the PCR polycarbonate is generally present in an amount of 0.05 to 1 wt %, specifically 0.1 to 0.25 wt %, based on the total weight of the PCR polycarbonate. When PCR polycarbonate is used in the flame retardant composition, it is present in amounts of 20 to 60 wt %, specifically 40 to 55 wt %., based on the total weight of the flame retardant composition.
The polycarbonate composition is used in amounts of 20 to 90 wt %, specifically 30 to 85 wt %, and more specifically 40 to 80 wt %, based on the total weight of the flame retardant composition.
The polycarbonate composition may further comprise a polysiloxane-polycarbonate copolymer, also referred to as a polysiloxane-carbonate copolymer. The polydiorganosiloxane (also referred to herein as “polysiloxane”) blocks of the copolymer comprise repeating diorganosiloxane units as in formula (19)
wherein each R is independently a C1-13 monovalent organic group. For example, R can be a C1-C13 alkyl, C1-C13 alkoxy, C2-C13 alkenyl group, C2-C13 alkenyloxy, C3-C6 cycloalkyl, C3-C6 cycloalkoxy, C6-C14 aryl, C6-C10 aryloxy, C7-C13 arylalkyl, C7-C13 aralkoxy, C7-C13 alkylaryl, or C7-C13 alkylaryloxy. The foregoing groups can be fully or partially halogenated with fluorine, chlorine, bromine, or iodine, or a combination thereof. Combinations of the foregoing R groups can be used in the same copolymer.
The value of E in formula (19) can vary widely depending on the type and relative amount of each component in the flame retardant composition, the desired properties of the composition, and like considerations. Generally, E has an average value of 2 to 1,000, specifically 3 to 500, more specifically 5 to 100. In an embodiment, E has an average value of 10 to 75, and in still another embodiment, E has an average value of 40 to 60. Where E is of a lower value, e.g., less than 40, it can be desirable to use a relatively larger amount of the polycarbonate-polysiloxane copolymer. Conversely, where E is of a higher value, e.g., greater than 40, a relatively lower amount of the polycarbonate-polysiloxane copolymer can be used.
A combination of a first and a second (or more) polycarbonate-polysiloxane copolymers can be used, wherein the average value of E of the first copolymer is less than the average value of E of the second copolymer.
In an embodiment, the polysiloxane blocks are of formula (20)
wherein E is as defined above; each R can be the same or different, and is as defined above; and Ar can be the same or different, and is a substituted or unsubstituted C6-C30 arylene group, wherein the bonds are directly connected to an aromatic moiety. Ar groups in formula (20) can be derived from a C6-C30 dihydroxyarylene compound, for example a dihydroxyarylene compound of formula (4) or (6) above. Exemplary dihydroxyarylene compounds are 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulfide), and 1,1-bis(4-hydroxy-t-butylphenyl)propane. Combinations comprising at least one of the foregoing dihydroxy compounds can also be used.
In another embodiment, polysiloxane blocks are of formula (21)
wherein R and E are as described above, and each R5 is independently a divalent C1-C30 organic group, and wherein the polymerized polysiloxane unit is the reaction residue of its corresponding dihydroxy compound. In a specific embodiment, the polysiloxane blocks are of formula (22):
wherein R and E are as defined above. R6 in formula (22) is a divalent C2-C8 aliphatic group. Each M in formula (22) can be the same or different, and can be a halogen, cyano, nitro, C1-C8 alkylthio, C1-C8 alkyl, C1-C8 alkoxy, C2-C8 alkenyl, C2-C8 alkenyloxy group, C3-C8 cycloalkyl, C3-C8 cycloalkoxy, C6-C10 aryl, C6-C10 aryloxy, C7-C12 aralkyl, C7-C12 aralkoxy, C7-C12 alkylaryl, or C7-C12 alkylaryloxy, wherein each n is independently 0, 1, 2, 3, or 4.
In an embodiment, M is bromo or chloro, an alkyl group such as methyl, ethyl, or propyl, an alkoxy group such as methoxy, ethoxy, or propoxy, or an aryl group such as phenyl, chlorophenyl, or tolyl; R6 is a dimethylene, trimethylene or tetramethylene group; and R is a C1-8 alkyl, haloalkyl such as trifluoropropyl, cyanoalkyl, or aryl such as phenyl, chlorophenyl or tolyl. In another embodiment, R is methyl, or a combination of methyl and trifluoropropyl, or a combination of methyl and phenyl. In still another embodiment, M is methoxy, n is one, R6 is a divalent C1-C3 aliphatic group, and R is methyl.
Specific polydiorganosiloxane blocks are of the formula
or a combination comprising at least one of the foregoing, wherein E has an average value of 2 to 200, 2 to 125, 5 to 125, 5 to 100, 5 to 50, 20 to 80, or 5 to 20.
In an embodiment, locks of formula (19) can be derived from the corresponding dihydroxy polysiloxane (23)
wherein R, E, M, R6, and n are as described above. Such dihydroxy polysiloxanes can be made by effecting a platinum-catalyzed addition between a siloxane hydride of formula (24)
wherein R and E are as previously defined, and an aliphatically unsaturated monohydric phenol. Exemplary aliphatically unsaturated monohydric phenols include eugenol, 2-alkylphenol, 4-allyl-2-methylphenol, 4-allyl-2-phenylphenol, 4-allyl-2-bromophenol, 4-allyl-2-t-butoxyphenol, 4-phenyl-2-phenylphenol, 2-methyl-4-propylphenol, 2-allyl-4,6-dimethylphenol, 2-allyl-4-bromo-6-methylphenol, 2-allyl-6-methoxy-4-methylphenol and 2-allyl-4,6-dimethylphenol. Combinations comprising at least one of the foregoing can also be used.
The polysiloxane-polycarbonate copolymer can comprise 50 to 99 weight percent of carbonate units and 1 to 50 weight percent siloxane units. Within this range, the polyorganosiloxane-polycarbonate copolymer can comprise 70 to 98 weight percent, more specifically 75 to 97 weight percent of carbonate units and 2 to 30 weight percent, more specifically 3 to 25 weight percent siloxane units. In an exemplary embodiment, the polysiloxane-polycarbonate copolymer is endcapped with para-cumyl phenol.
In an embodiment, an exemplary polysiloxane-polycarbonate copolymer is a block copolymer having the structure shown in the Formula (25) below:
where the polysiloxane blocks are endcapped with eugenol, where x is 1 to 100, specifically 5 to 85, specifically 10 to 70, specifically 15 to 65, and more specifically 40 to 60. In an embodiment, y is 1 to 90 and z is 1 to 600. The polysiloxane block may be randomly distributed or controlled distributed amongst the polycarbonate blocks. In an embodiment, x is 30 to 50, y is 10 to 30, and z is 450 to 600.
When the polysiloxane polycarbonate copolymer comprises eugenol endcapped polysiloxane, the flame retardant composition comprises 5 to 85 wt % of the polysiloxane-polycarbonate copolymer. The polysiloxane content is 1 to 25 wt %, specifically 1 to 16 wt %, specifically 2 to 14 wt %, and more specifically 3 to 6 wt %, based on the total weight of the polysiloxane-polycarbonate copolymer. In an embodiment, the weight average molecular weight of the polysiloxane block is 25,000 to 30,000 Daltons using gel permeation chromatography with a bisphenol A polycarbonate absolute molecular weight standard. In an exemplary embodiment, the polysiloxane content is 15 to 25 wt %, based on the total weight of the polysiloxane-polycarbonate copolymer.
In an embodiment, the polysiloxane-polycarbonate copolymer comprises 10 wt % or less, specifically 6 wt % or less, and more specifically 4 wt % or less, of the polysiloxane based on the total weight of the polysiloxane-polycarbonate copolymer. Polysiloxane-polycarbonate copolymers containing 10 wt % or less are generally optically transparent and are sometimes referred to as EXL-T as commercially available from SABIC.
In another embodiment, the polysiloxane-polycarbonate copolymer comprises 10 wt % or more, specifically 12 wt % or more, and more specifically 14 wt % or more, of the polysiloxane based on the total weight of the polysiloxane-polycarbonate copolymer. Polysiloxane-carbonate copolymers containing 10 wt % or more polysiloxane are generally optically opaque and are sometimes referred to as EXL-P as commercially available from SABIC.
The polysiloxane polycarbonate copolymer can have a weight average molecular weight of 2,000 to 100,000 Daltons, specifically 5,000 to 50,000 Daltons as measured by gel permeation chromatography using a crosslinked styrene-divinyl benzene column, at a sample concentration of 1 milligram per milliliter, and as calibrated with polycarbonate standards. In an embodiment, the polysiloxane polycarbonate copolymer can have a weight average molecular weight of greater than or equal to 30,000 Daltons, specifically greater than or equal to 31,000 Daltons, and more specifically greater than or equal to 32,000 Daltons as measured by gel permeation chromatography using a crosslinked styrene-divinyl benzene column, at a sample concentration of 1 milligram per milliliter, and as calibrated with polycarbonate standards.
The polysiloxane polycarbonate copolymer can have a melt volume flow rate, measured at 300° C./1.2 kg, of 1 to 50 cubic centimeters per 10 minutes (cc/10 min), specifically 2 to 30 cc/10 min. Mixtures of polysiloxane polycarbonate copolymer of different flow properties can be used to achieve the overall desired flow property.
When the polycarbonate composition comprises an opaque polysiloxane-carbonate copolymer, it is generally used in an amount of 5 to 27 wt %, 10 to 25 wt %, and more specifically 12 to 22 wt %, based on the total weight of the flame retardant composition.
The flame retardant composition can optionally include impact modifier(s). Suitable impact modifiers are typically high molecular weight elastomeric materials derived from olefins, monovinyl aromatic monomers, acrylic and methacrylic acids and their ester derivatives, as well as conjugated dienes. The polymers formed from conjugated dienes can be fully or partially hydrogenated. The elastomeric materials can be in the form of homopolymers or copolymers, including random, block, radial block, graft, and core-shell copolymers. Combinations of impact modifiers can be used.
A specific type of impact modifier is an elastomer-modified graft copolymer comprising (i) an elastomeric (i.e., rubbery) polymer substrate having a Tg less than 10° C., more specifically less than −10° C., or more specifically −40° to −80° C., and (ii) a rigid polymeric shell grafted to the elastomeric polymer substrate. Materials suitable for use as the elastomeric phase include, for example, conjugated diene rubbers, for example polybutadiene and polyisoprene; copolymers of a conjugated diene with less than 50 wt % of a copolymerizable monomer, for example a monovinylic compound such as styrene, acrylonitrile, n-butyl acrylate, or ethyl acrylate; olefin rubbers such as ethylene propylene copolymers (EPR) or ethylene-propylene-diene monomer rubbers (EPDM); ethylene-vinyl acetate rubbers; silicone rubbers; elastomeric C1-8 alkyl (meth)acrylates; elastomeric copolymers of C1-8 alkyl (meth)acrylates with butadiene and/or styrene; or combinations comprising at least one of the foregoing elastomers. materials suitable for use as the rigid phase include, for example, monovinyl aromatic monomers such as styrene and alpha-methyl styrene, and monovinylic monomers such as acrylonitrile, acrylic acid, methacrylic acid, and the C1-C6 esters of acrylic acid and methacrylic acid, specifically methyl methacrylate.
Specific exemplary elastomer-modified graft copolymers include those formed from styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), styrene-ethylene-butadiene-styrene (SEBS), ABS (acrylonitrile-butadiene-styrene), acrylonitrile-ethylene-propylene-diene-styrene (AES), styrene-isoprene-styrene (SIS), methyl methacrylate-butadiene-styrene (MBS), and styrene-acrylonitrile (SAN).
Impact modifiers are generally present in amounts of 1 to 30 wt %, specifically 3 to 20 wt %, based on the total weight of the polymers in the flame retardant composition. An exemplary impact modifier comprises an acrylic polymer in an amount of 2 to 15 wt %, specifically 3 to 12 wt %, based on the total weight of the flame retardant composition.
The flame retardant composition may also comprise mineral fillers. In an embodiment, the mineral fillers serve as synergists. The synergist facilitates an improvement in the flame retardant properties when added to the flame retardant composition over a comparative polycarbonate composition that contains all of the same ingredients in the same quantities except for the synergist. Examples of mineral fillers are mica, talc, calcium carbonate, dolomite, wollastonite, barium sulfate, silica, kaolin, feldspar, barytes, or the like, or a combination comprising at least one of the foregoing mineral fillers. The mineral filler may have an average particle size of 0.1 to 20 micrometers, specifically 0.5 to 10 micrometers, and more specifically 1 to 3 micrometers. An exemplary mineral filler it talc having an average particle size of 1 to 3 micrometers.
The mineral filler is present in amounts of 0.1 to 20 wt %, specifically 0.5 to 15 wt %, and more specifically 1 to 5 wt %, based on the total weight of the flame retardant composition.
The flame retardant composition may also optionally contain additives such as antioxidants, antiozonants, stabilizers, thermal stabilizers, mold release agents, dyes, colorants, pigments, flow modifiers, or the like, or a combination comprising at least one of the foregoing additives.
As noted above, the flame retardant composition comprises a flame retarding agent. The flame retarding agent is a phosphazene compound. In an embodiment, the flame retarding agent is a phenoxyphosphazene oligomer.
The phosphazene compound used in the flame retardant composition is an organic compound having a —P═N— bond in the molecule. In an embodiment, the phosphazene compound comprises at least one species of the compound selected from the group consisting of a cyclic phenoxyphosphazene represented by the formula (26) below; a chainlike phenoxyphosphazene represented by the formula (27) below; and a crosslinked phenoxyphosphazene compound obtained by crosslinking at least one species of phenoxyphosphazene selected from those represented by the formulae (26) and (27) below, with a crosslinking group represented by the formula (28) below:
where in the formula (26), m represents an integer of 3 to 25, R1 and R2 are the same or different and are independently a hydrogen, a hydroxyl, a C7-30 aryl group, a C1-12 alkoxy, or a C1-12 alkyl.
The chainlike phenoxyphosphazene represented by the formula (27) below:
where in the formula (27), X1 represents a —N═P(OPh)3 group or a —N═P(O)OPh group, Y1 represents a —P(OPh)4 group or a —P(O)(OPh)2 group, n represents an integer from 3 to 10000, Ph represents a phenyl group, R1 and R2 are the same or different and are independently a hydrogen, a halogen, a C1-12 alkoxy, or a C1-12 alkyl.
The phenoxyphosphazenes may also have a crosslinking group represented by the formula (28) below:
where in the formula (18), A represents —C(CH3)2—, —SO2—, —S—, or —O—, and q is 0 or 1.
In an embodiment, the phenoxyphosphazene compound has a structure represented by the formula (29)
where R1 to R6 can be the same of different and can be an aryl group, an aralkyl group, a C1-12 alkoxy, a C1-12 alkyl, or a combination thereof.
In an embodiment, the phenoxyphosphazene compound has a structure represented by the formula (30)
Commercially available phenoxyphosphazenes having the aforementioned structures are LY202® manufactured and distributed by Lanyin Chemical Co., Ltd, FP-110® manufactured and distributed by Fushimi Pharmaceutical Co., Ltd, and SPB-100® manufactured and distributed by Otsuka Chemical Co., Ltd.
The cyclic phenoxyphosphazene compound represented by the formula (26) may be exemplified by compounds such as phenoxy cyclotriphosphazene, octaphenoxy cyclotetraphosphazene, and decaphenoxy cyclopentaphosphazene, obtained by allowing ammonium chloride and phosphorus pentachloride to react at 120 to 130° C. to obtain a mixture containing cyclic and straight chain chlorophosphazenes, extracting cyclic chlorophosphazenes such as hexachloro cyclotriphosphazene, octachloro cyclotetraphosphazene, and decachloro cyclopentaphosphazene, and then substituting it with a phenoxy group. The cyclic phenoxyphosphazene compound may be a compound in which m in the formula (26) represents an integer of 3 to 8.
The chainlike phenoxyphosphazene compound represented by the formula (27) is exemplified by a compound obtained by subjecting hexachloro cyclotriphosphazene, obtained by the above-described method, to ring-opening polymerization at 220 to 250° C., and then substituting thus obtained chainlike dichlorophosphazene having a degree of polymerization of 3 to 10000 with phenoxy groups. The chain-like phenoxyphosphazene compound has a value of n in the formula (27) of 3 to 1000, specifically 5 to 100, and more specifically 6 to 25.
The crosslinked phenoxyphosphazene compound may be exemplified by compounds having a crosslinked structure of a 4,4′-diphenylene group, such as a compound having a crosslinked structure of a 4,4′-sulfonyldiphenylene (bisphenol S residue), a compound having a crosslinked structure of a 2,2-(4,4′-diphenylene)isopropylidene group, a compound having a crosslinked structure of a 4,4′-oxydiphenylene group, and a compound having a crosslinked structure of a 4,4′-thiodiphenylene group. The phenylene group content of the crosslinked phenoxyphosphazene compound is generally 50 to 99.9 wt %, and specifically 70 to 90 wt %, based on the total number of phenyl group and phenylene group contained in the cyclic phosphazene compound represented by the formula (26) and/or the chainlike phenoxyphosphazene compound represented by the formula (27). The crosslinked phenoxyphosphazene compound may be particularly preferable if it doesn't have any free hydroxyl groups in the molecule thereof. In an exemplary embodiment, the phosphazene compound comprises the cyclic phosphazene.
It is desirable for the flame retardant composition to comprise the phosphazene compound in an amount of 1 to 20 wt %, specifically 2 to 16 wt %, and more specifically 2.5 wt % to 14 wt %, and more specifically 3 to 10 wt %, based on the total weight of the flame retardant composition.
The flame retardant composition may also optionally comprise an acid or an acid salt in order to mitigate a reduction in the molecular weight of the polycarbonate or the polyester during processing. Examples of acids that may be used in the flame retardant compositions are phosphoric acid, phosphorous acid, hypophosphorous acid, hypophosphoric acid, phosphinic acid, phosphonic acid, phosphonous acid ester, metaphosphoric acid, hexametaphosphoric acid, thiophosphoric acid, fluorophosphoric acid, difluorophosphoric acid, fluorophosphorous acid, difluorophosphorous acid, fluorohypophosphorous acid, or fluorohypophosphoric acid. Alternatively, acids and acid salts, such as, for example, sulphuric acid, sulphites, mono zinc phosphate, mono calcium phosphate, mono natrium phosphate, or the like, or a combination comprising at least one of the foregoing acids may be used in the flame retardant composition. The acid or acid salt is selected so that it can be effectively combined with a mineral filler to produce a synergistic effect and a balance of properties, such as flow and impact, in the flame retardant compositions.
The acid may be present in amounts of about 0.00001 to about 1.0 wt %, specifically about 0.0001 to about 0.1 wt %, based on the total weight of the flame retardant polycarbonate composition.
In one embodiment, the flame retardant composition may contain reinforcing fillers. Examples of reinforcing fillers are glass fibers, carbon fibers, metal fibers, and the like.
The glass fibers may be flat or round fibers. Flat glass fibers have an elliptical cross-sectional area, while round fibers have a circular cross-sectional area, where the cross-sectional areas are measured perpendicular to the longitudinal axis of the fiber. The glass fibers may be manufactured from “E-glass,” “A-glass,” “C-glass,” “D-glass,” “R-glass,” “S-glass,” as well as E-glass derivatives that are fluorine-free and/or boron-free. The glass fibers may be woven or non-woven. The glass fibers can have a diameter of about 3 micrometers to about 25 micrometers, specifically about 4 micrometers to about 20 micrometers, and more specifically about 8 micrometers to about 15 micrometers.
The carbon fibers may be either carbon nanotubes or carbon fibers derived from pitch or polyacrylonitrile. The carbon nanotubes can be single wall carbon nanotubes or multiwall carbon nanotubes. The carbon nanotubes can have diameters of about 2.7 nanometers to about 100 nanometers and can have aspect ratios of about 5 to about 100. The aspect ratio is defined as the ratio of the length to the diameter.
The carbon fibers derived from pitch and polyacrylonitrile have a different microstructure from the carbon nanotubes. The carbon fibers can have a diameter of about 3 micrometers to about 25 micrometers, specifically about 4 micrometers to about 20 micrometers, and more specifically about 8 micrometers to about 15 micrometers and can have aspect ratios of about 0.5 to about 100.
The metal fibers can be whiskers (having diameters of less than 100 nanometers) or can have diameters in the micrometer regime. Metal fibers in the micrometer regime can have diameters of about 3 to about 30 micrometers. Exemplary metal fibers comprise stainless steel, aluminum, iron, nickel, copper, or the like, or a combination comprising at least one of the foregoing metals. In an exemplary embodiment, the reinforcing fibers comprise fiber glass. The fiber glass can be bonding or can be non-bonding.
The flame retardant composition comprises the reinforcing fibers in an amount of about 5 to about 45 wt %, specifically about 20 to about 40 wt %, and more specifically about 28 to about 33 wt %, based on the total weight of the flame retardant composition. In an exemplary embodiment, the reinforcing fiber is fiberglass and comprises 10 to 30 wt %, based on the total weight of the flame retardant composition.
The flame retardant composition may also contain pentaerythritol tetrastearate in amounts of 0.01 to 2.0 wt %, based on the total weight of the flame retardant composition.
In an embodiment, the flame retardant composition may comprise an anti-drip agent. Fluorinated polyolefin and/or polytetrafluoroethylene may be used as an anti-drip agent. Anti-drip agents may also be used, for example a fibril forming or non-fibril forming fluoropolymer such as polytetrafluoroethylene (PTFE). The anti-drip agent may be encapsulated by a rigid copolymer such as, for example styrene acrylonitrile (SAN). PTFE encapsulated in SAN is known as TSAN. Encapsulated fluoropolymers may be made by polymerizing the encapsulating polymer in the presence of the fluoropolymer, for example, in an aqueous dispersion. TSAN may provide significant advantages over PTFE, in that TSAN may be more readily dispersed in the composition. A suitable TSAN may comprise, for example, 50 wt % PTFE and 50 wt % SAN, based on the total weight of the encapsulated fluoropolymer. The SAN may comprise, for example, 75 wt % styrene and 25 wt % acrylonitrile based on the total weight of the copolymer. Alternatively, the fluoropolymer may be pre-blended in some manner with a second polymer, such as for, example, an aromatic polycarbonate resin or SAN to form an agglomerated material for use as an anti-drip agent. Either method may be used to produce an encapsulated fluoropolymer.
The anti-drip agent may be added in the form of relatively large particles having a number average particle size of 0.3 to 0.7 mm, specifically 0.4 to 0.6 millimeters. The anti-drip agent may be used in amounts of 0.01 wt % to 5.0 wt %, specifically 0.1 to 1.0 wt %, and more specifically 0.2 to 0.8 wt %, based on the total weight of the flame retardant composition.
In an embodiment, the flame retardant composition may contain a silicone oil. The silicone oil a high viscosity silicone containing a combination of a linear silicone fluid, and a silicone resin that is solubilized in the fluid.
The silicone oil is present in an amount of 0.5 to 10 wt %, specifically 1 to 5 wt %, based on the total weight of the flame retardant composition. In one embodiment, the silicone oil comprises a polysiloxane polymer endcapped with trimethylsilane; where the silicone oil has a viscosity at 25° C. of 20,000 to 900,000 square millimeter per second. A commercially available silicone oil for use in the flame retardant composition is SFR®-100 commercially available from Momentive.
In an embodiment, the flame retardant composition may optionally comprise other flame retardants in addition to or instead of the phenoxyphosphazene compounds. These additional flame retardants may be bisphenol A diphosphate, resorcinol diphosphate, brominated polycarbonate, Rimar salt (potassium perfluorobutane sulfonate) KSS (potassium diphenylsulfone sulfonated, and the like. These additional flame retardants may be used in amounts of 0.5 to 10 wt %, specifically 1 to 5 wt %, based on the total weight of the flame retardant composition.
In another embodiment, pigments may be added to the flame retardant composition. The pigments may act synergistically with the phosphazene compound, the polysiloxane-carbonate copolymer to produce flame retardant products that display flame retardancy of 5VA at a thickness of 2 millimeters. Examples of pigments are carbon nanotubes, silica, alumina, zinc oxide, titanium dioxides, BaSO4, CaCO3, BaTiO3, iron oxides, zinc sulfide, aluminates; sodium sulfo-silicates; sulfates and chromates; zinc ferrites; ultramarine blue; Pigment Brown 24; Pigment Red 101; Pigment Yellow 119; Pigment black 28; organic pigments such as azos, di-azos, quinacridones, perylenes, naphthalene tetracarboxylic acids, flavanthrones, isoindolinones, tetrachloroisoindolinones, anthraquinones, anthanthrones, dioxazines, phthalocyanines, and azo lakes; Pigment Blue 60, Pigment Red 122, Pigment Red 149, Pigment Red 177, Pigment Red 179, Pigment Red 202, Pigment Violet 29, Pigment Blue 15, Pigment Green 7, Pigment Yellow 147 and Pigment Yellow 150, coumarin 460 (blue), coumarin 6 (green), nile red, lanthanide complexes, hydrocarbon and substituted hydrocarbon dyes, polycyclic aromatic hydrocarbons, scintillation dyes (e.g., oxazoles and oxadiazoles), aryl- or heteroaryl-substituted poly (2-8 olefins), carbocyanine dyes, phthalocyanine dyes and pigments, oxazine dyes, carbostyryl dyes, porphyrin dyes, acridine dyes, anthraquinone dyes, arylmethane dyes, azo dyes, diazonium dyes, nitro dyes, quinone imine dyes, tetrazolium dyes, thiazole dyes, perylene dyes, perinone dyes, bis-benzoxazolylthiophene (BBOT), and xanthene dyes, fluorophores such as anti-stokes shift dyes which absorb in the near infrared wavelength and emit in the visible wavelength, or the like, luminescent dyes such as 5-amino-9-diethyliminobenzo(a)phenoxazonium perchlorate, 7-amino-4-methylcarbostyryl, 7-amino-4-methylcoumarin, 3-(2′-benzimidazolyl)-7-N,N-diethylaminocoumarin, 3-(2′-benzothiazolyl)-7-diethylaminocoumarin, 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2-(4-biphenyl)-6-phenylbenzoxazole-1,3,2,5-Bis-(4-biphenylyl)-1,3,4-oxadiazole, 2,5-bis-(4-biphenylyl)-oxazole, 4,4′-bis-(2-butyloctyloxy)-p-quaterphenyl, p-bis(o-methylstyryl)-benzene, 5,9-diaminobenzo(a)phenoxazonium perchlorate, 4-dicyanomethylene-2-methyl-6-(p-dimethylamino styryl)-4H-pyran, 1,1′-diethyl-2,2′-carbocyanine iodide, 3,3′-diethyl-4,4′,5,5′-dibenzothiatricarbocyanine iodide, 7-diethylamino-4-methylcoumarin, 7-diethylamino-4-trifluoromethylcoumarin, 2,2′-dimethyl-p-quaterphenyl, 2,2-dimethyl-p-terphenyl, 7-ethylamino-6-methyl-4-trifluoromethylcoumarin, 7-ethylamino-4-trifluoromethylcoumarin, nile red, rhodamine 700, oxazine 750, rhodamine 800, IR 125, IR 144, IR 140, IR 132, IR 26, IRS, diphenylhexatriene, diphenylbutadiene, tetraphenylbutadiene, naphthalene, anthracene, 9,10-diphenylanthracene, pyrene, chrysene, rubrene, coronene, phenanthrene or the like, or a combination comprising at least one of the foregoing pigments. An exemplary flame retardant composition may contain titanium dioxide and carbon black as pigments. The flame retardant composition comprise 0.5 to 15 wt % of a pigment, specifically 2 to 12 wt % of a pigment, based on the total weight of the flame retardant composition
Other additives such as anti-oxidants, anti-ozonants, mold release agents, thermal stabilizers, levelers, viscosity modifying agents, free-radical quenching agents, other polymers or copolymers such as impact modifiers, or the like.
The preparation of the flame retardant composition can be achieved by blending the ingredients under conditions that produce an intimate blend. All of the ingredients can be added initially to the processing system, or else certain additives can be precompounded with one or more of the primary components.
In an embodiment, the flame retardant composition is manufactured by blending the polycarbonate composition with the phosphazene compound and the laser direct structuring additive. The blending can be dry blending, melt blending, solution blending, or a combination comprising at least one of the foregoing forms of blending.
In an embodiment, the flame retardant composition can be dry blended to form a mixture in a device such as a Henschel mixer or a Waring blender prior to being fed to an extruder, where the mixture is melt blended. In another embodiment, a portion of the polycarbonate composition can be premixed with the phosphazene compound to form a dry preblend. The dry preblend is then melt blended with the remainder of the polycarbonate composition in an extruder. In an embodiment, some of the flame retardant composition can be fed initially at the mouth of the extruder while the remaining portion of the flame retardant composition is fed through a port downstream of the mouth.
Blending of the flame retardant composition involves the use of shear force, extensional force, compressive force, ultrasonic energy, electromagnetic energy, thermal energy or combinations comprising at least one of the foregoing forces or forms of energy and is conducted in processing equipment wherein the aforementioned forces are exerted by a single screw, multiple screws, intermeshing co-rotating or counter rotating screws, non-intermeshing co-rotating or counter rotating screws, reciprocating screws, screws with pins, barrels with pins, rolls, rams, helical rotors, or combinations comprising at least one of the foregoing.
Blending involving the aforementioned forces may be conducted in machines such as single or multiple screw extruders, Buss kneader, Henschel, helicones, Ross mixer, Banbury, roll mills, molding machines such as injection molding machines, vacuum forming machines, blow molding machine, or then like, or combinations comprising at least one of the foregoing machines.
The flame retardant composition can be introduced into the melt blending device in the form of a masterbatch. For example, a portion of the polycarbonate composition can be pre-blended with the phosphazene flame retardant to form a masterbatch, which is then blended with the remaining ingredients to form the flame retardant composition. In such a process, the masterbatch may be introduced into the blending device downstream of the point where the remaining ingredients of the flame retardant composition are introduced.
In an embodiment, the flame retardant composition disclosed herein is used to prepare molded articles such as for example, durable articles, electrical and electronic components, automotive parts, and the like. The compositions can be converted to articles using common thermoplastic processes such as film and sheet extrusion, injection molding, gas-assisted injection molding, extrusion molding, compression molding and blow molding.
In an embodiment, the flame retardant compositions when prepared into test specimens having a thickness of at least 1.2 mm, exhibit a flammability class rating according to Underwriters Laboratories Inc. UL-94 of at least V-2, more specifically at least V-1, and yet more specifically at least V-0. In another embodiment, the flame retardant compositions when prepared into specimens having a thickness of at least 2.0 millimeters, exhibit a flammability class rating according to Underwriters Laboratories Inc. UL-94 of at least V-2, more specifically at least V-1, and yet more specifically at least V-0.
Flammability tests were performed following the procedure of Underwriter's Laboratory Bulletin 94 entitled “Tests for Flammability of Plastic Materials, UL 94”. Several ratings can be applied based on the rate of burning, time to extinguish, ability to resist dripping, and whether or not drips are burning. Samples for testing are bars having dimensions of 125 mm length×13 mm width by no greater than 13 mm thickness. Bar thicknesses were 0.6 mm or 0.8 mm. Materials can be classified according to this procedure as UL 94 HB (horizontal burn), V0, V1, V2, 5VA and/or 5VB on the basis of the test results obtained for five samples; however, the compositions herein were tested and classified only as V0, V1, and V2, the criteria for each of which are described below.
V0: In a sample placed so that its long axis is 180 degrees to the flame, the period of flaming and/or smoldering after removing the igniting flame does not exceed ten (10) seconds and the vertically placed sample produces no drips of burning particles that ignite absorbent cotton. Five bar flame out time is the flame out time for five bars, each lit twice, in which the sum of time to flame out for the first (t1) and second (t2) ignitions is less than or equal to a maximum flame out time (t1+t2) of 50 seconds.
V1: In a sample placed so that its long axis is 180 degrees to the flame, the period of flaming and/or smoldering after removing the igniting flame does not exceed thirty (30) seconds and the vertically placed sample produces no drips of burning particles that ignite absorbent cotton. Five bar flame out time is the flame out time for five bars, each lit twice, in which the sum of time to flame out for the first (t1) and second (t2) ignitions is less than or equal to a maximum flame out time (t1+t2) of 250 seconds.
V2: In a sample placed so that its long axis is 180 degrees to the flame, the average period of flaming and/or smoldering after removing the igniting flame does not exceed thirty (30) seconds, but the vertically placed samples produce drips of burning particles that ignite cotton. Five bar flame out time is the flame out time for five bars, each lit twice, in which the sum of time to flame out for the first (t1) and second (t2) ignitions is less than or equal to a maximum flame out time (t1+t2) of 250 seconds.
In an embodiment, the flame retardant compositions are of particular utility in the manufacture flame retardant articles that pass the UL94 vertical burn tests, in particular the UL94 5VB standard. In the UL94 vertical burn test, a flame is applied to a vertically fastened test specimen placed above a cotton wool pad. To achieve a rating of 5VB, burning must stop within 60 seconds after five applications of a flame to a test bar, and there can be no drips that ignite the pad.
If a sample can pass 5VB, then the sample can continue to be tested on 5VA to get a 5VA listing. Various embodiments of the compositions described on 5VA meet the UL94 5VB standard. The test is conducted as follows:
Support the plaque specimen (150±5 mm×150±5 mm) by a clamp on the ring stand in the horizontal plane. The flame is then to be applied to the center of the bottom surface of the plaque at an angle of 20±5° from the vertical, so that the tip of the blue cone just touches the specimen. Apply the flame for 5±0.5 seconds and then remove for 5±0.5 seconds. Repeat the operation until the plaque specimen has been subjected to five applications of the test flame. When desired, to complete the test, hand hold the burner and fixture so that the tip of the inner blue cone maintains contact with the surface of the plaque. After the fifth application of the test flame, and after all flaming or glowing combustion has ceased, it is to be observed and recorded whether or not the flame penetrated (burned through) the plaque.
Izod Impact Strength is used to compare the impact resistances of plastic materials. Notched Izod impact strength was determined at both 23° C. and 0° C. using a 3.2-mm thick, molded, notched Izod impact bar. It was determined per ASTM D256. The results are reported in Joules per meter. Tests were conducted at room temperature (23° C.) and at a low temperature (−20° C.).
Heat deflection temperature (HDT) is a relative measure of a material's ability to perform for a short time at elevated temperatures while supporting a load. The test measures the effect of temperature on stiffness: a standard test specimen is given a defined surface stress and the temperature is raised at a uniform rate. HDT was determined as flatwise under 1.82 MPa loading with 3.2 mm thickness bar according to ASTM D648. Results are reported in ° C.
Melt volume rate (MVR) is measured 300° C./1.2 kg as per ASTM D 1238.
The flame retardant composition displays an advantageous combination of properties such as ductility, melt processability, impact strength, and flame retardancy.
The following examples, which are meant to be exemplary, not limiting, illustrate the flame retardant compositions and methods of manufacturing of some of the various embodiments of the flame retardant compositions described herein.
EXAMPLES Example 1This example was conducted to demonstrate the disclosed composition and the method of manufacturing a flame retardant composition that comprises the polycarbonate composition, a phosphazene flame retardant and a pigment (e.g., a TiO2) filler. This example also demonstrates the synergy between the polysiloxane-carbonate copolymer and the phenoxyphosphazene. The polycarbonate composition comprises a polycarbonate (PC1, PC2, and/or PC3), an opaque polysiloxane-carbonate copolymer (PC4), a copolycarbonate that has a glass transition temperature greater than or equal to 170° C. (PC5), and a post-consumer recycle polycarbonate that contains polyester contamination (PC6). As can be seen in the tables below, the polycarbonate composition is used in amounts of 45 to 90 wt %, based on the total weight of the flame retardant composition.
The phosphazene was SPB-100 commercially available from Otsuka. Comparative flame retardants such as BPADP, Rimar salt, and KSS were also used. In this example, the BPADP, Rimar salt, and KSS are comparative flame retardants and compositions containing the BPADP, RDP, and KSS are therefore comparative compositions.
The polycarbonate composition along with the other ingredients used in this example are shown in the Table 1. Table 2 lists the compounding conditions in the extruder, while Table 3 lists the compounding conditions in the molding machine. Tables 4, 5, and 6 list comparative compositions along with compositions of the disclosure.
The compounding was conducted on a Toshiba SE37 mm twin-screw extruder having 11 barrels. The temperature for each of the barrels is detailed in the Table 2. The molding conditions are detailed in the Table 3. All the components were fed from main throat from upper stream. The various compositions along with the properties are detailed in the Table 4. The test standards used for the property measurements are detailed in the respective property tables.
The compositions were all compounded from twin-screw extruder, and the pellets were collected for evaluation and molding. The ASTM standard molded parts were evaluated accordingly to the standards for flexural, tensile, notched Izod and multi axis impact. The standards used are detailed above.
Tables 4, 5, 6, 7, and 8 all detail the flame retardant compositions (both comparative compositions as well as the disclosed composition) as well as the properties for each composition. In these tables, comparative flame retardant compositions that contain BPADP, KSS or Rimar salt are compared with the disclosed flame retardant compositions that contain the phosphazene compound. All of the compositions in the Tables 4 through 8, were extruded and molded as shown in the Tables 2 and 3.
From the Table 4, it may be seen that a lower level of the phosphazene compound may be used to attain the same level of phosphorus in the final formulation when compared with a comparative flame retardant BPADP. In other words comparing comparative example 2 (CEx. #2) with example #1 (Ex. #1) shows that a smaller amount of the phosphazene compound (2 wt % versus 1.37 wt %) may be used to impart the same amount of phosphorus (0.18 wt %) to the respective flame retardant composition.
The results show that at a level of 2 wt % no solid 1 mm V-0 rating is attained with BPADP, whereas a similar phosphorus-level from the phosphazene compound gives a lower flame out time (FOT) and higher probability of a first time pass p(FTP) for samples having a thickness of greater than or equal to 1.0 millimeter.
At higher loading levels, BPADP can also give a flame retardancy of V-0 at 1.0 mm thickness, but both Vicat hardness and the impact strength drop severely. Flame retardant compositions containing the phosphazene compound show superior Vicat hardness and impact strength respectively. The loss in heat resistance for samples containing BPADP can be compensated for by using increased amounts of a high heat polycarbonate (e.g., 18 wt % of PC5), but this promotes a further decrease in impact strength. Comparing Comparative example 4 (CEx. #4) with Ex. #2 (which is the disclosed composition), the melt volume rate (MVR), Vicat and the probability of a first time pass (p(FTP)) are similar, but there is a large difference in the notched Izod between the two samples. The notched Izod impact strength for the composition containing the phosphazene compound is at least 10% greater than the sample containing the BPADP.
Table 5 shows the results for the various comparative flame retardant additives used in combination with post-consumer recycle (PCR) from polycarbonate recycled water bottles. The Table 5 shows compositions and properties for comparative compositions (CEx. #s 5-13) containing the comparative flame retardants BPADP, Rimar salts, or KSS along with the post-consumer recycle polycarbonate (PC6). The PC6 is present in an amount of 27 wt %, based on the total weight of the flame retardant composition. No samples that represent the disclosed composition are reflected in the Table 5 (i.e., no samples that contain phenoxyphosphazene). High heat polycarbonate PC5 was also used in these compositions in amounts of 4.5 and 9 wt % respectively in some of the comparative flame retardant compositions.
In formulation (CEx. #5) in the Table 5, it may be seen that 2 wt % BPADP is enough to give a flame retardancy of V-0 at 1.5 millimeter thickness. The PCR raw material can be contaminated with polyester from water bottles and CEx. #6 shows that flame retardant properties become less robust if the PCR has only 0.5% polyester contamination, which is commonly found in PCR material.
When a white material is needed, very high levels of titanium dioxide (TiO2) (in amounts of greater than or equal to 5%) are used to hide the blue color of the PCR. At 5.7 wt % of TiO2 (CEx. #7), a nice white colored composition is obtained, but the probability of a first time pass p(FTP) drops to 0.00. In other words, the addition of titanium dioxide reduces the flame retardancy of the compositions. CEx. #8 and #9 show that flame retardancy robustness can regained by simultaneously increasing BPADP and the PC5 level to maintain heat resistance at the same level. However, once again it may be seen that polyester contamination results in non-robust performance (CEx. #10). From the Table 5, it may be seen that other flame retardant additives (CEx. #11 to 13) lead to non-robust behavior even without contamination or with lower than or equal to 5% TiO2.
In the Table 6, it may be seen that the comparative flame retardants are replaced with the phosphazene compound SPB-100 from Otsuka. The results of the Table 6 (for the disclosed composition) may be compared with the results from the Table 5. Table 6 shows that SPB-100 is much more effective and can provide a robust flame retardancy of V-0 at a thickness of 1.5 mm at phosphazene levels of greater 1.5 wt % even in presence of 5.7 wt % TiO2 and with a PCR polycarbonate that contains polyester contamination and therefore contributes the polyester contamination to the flame retardant composition.
From examples Ex #s 4-7 in the Table 6 above, it may be seen that as the amount of phosphazene compound is increased from 1.5 to 2.25 weight percent the flame retardancy as expressed by p(FTP) increases from 0.74 to 1.0 at a thickness of 1.5 millimeters. Flame retardant compositions that contain 2.5 or 3 wt % of the BPADP (CEx. #8 and CEx. #9) in the Table 5 show a p(FTP) value that is lower than a flame retardant composition that contains 2.25 wt % of the phosphazene compound (e.g., Ex. #7 in the Table 6), even though the Ex. #7 in the Table 6 contains polyester contamination, while the comparative samples from Table 5 (CEx. #8 and CEx. #9) do not.
The examples of Table 7 were conducted to show some of the results for the use of BPADP to attain thin wall flame retardant properties and a comparative tracking index (CTI2) rating. Table 7 contains all comparative examples. The Comparative Tracking Index or CTI is used to measure the electrical breakdown (tracking) properties of an insulating material. To measure the tracking, 52 drops of 0.1% ammonium chloride solution are dropped on the material, and the voltage measured for a 3 mm thick sample is considered representative of the material performance.
From the Table 7, it may be seen that large amounts of TiO2 (of greater than or equal to 3 wt %, based on the total weight of the composition) are used to facilitate the achievement of the desired CTI2 specification of greater than 50 drops at 250 Volts, when BPADP is used as a flame retardant. Even at high BPADP levels, it is difficult to get a reproducible 0.8 mm V-0 rating. High levels of PC5 are therefore added to the flame retardant composition containing the BPADP in order to pass the BPT at 125° C.
Table 8 shows that a balance of properties that could not be attained with the use of BPADP is much easier attained when a phosphazene flame retardant is used in the flame retardant composition instead of BPADP, Rimar salts or KSS. Table 8 contains examples that demonstrate the disclosed flame retardant compositions. As may be seen in the Table 8, at levels of greater than or equal to 3.5 wt % a solid 0.8 mm V-0 is attained, while maintaining a good enough heat resistance to pass the BPT test at 125° C. Reducing the TSAN level to 0.3 wt % further improves the FR robustness. When carbon black is used as a pigment to attain a darker color, only 2.5 wt % of the phosphazene compound is used, although EXL level is increased in order to achieve 100% ductility at −30° C.
From the foregoing Table 8, it may be seen that the use of phenoxyphosphazene in a flame retardant composition that comprises titanium dioxide in amounts of 1 to 15 wt % and/or carbon black in amounts of about 0.1 to 5 wt %, a polycarbonate composition comprising polycarbonate in amounts of about 20 to 90 wt %, produces an effective combination of flame retardancy, flow properties and impact strength. In the polycarbonate composition, the polysiloxane-carbonate copolymer is used in amounts of about 5 to about 30 wt %, and XHT polycarbonate (polycarbonate derived from the structure of formula (9)—also called 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP)) is used in amounts of about 5 to about 30 wt %, based on the total weight of the flame retardant composition.
In one embodiment (from the Table 8), it may be seen that the flame retardant composition comprises titanium dioxide in amounts of 1 to 15 wt % and/or carbon black in amounts of about 0.1 to 5 wt %, a polycarbonate composition comprising polycarbonate in amounts of about 20 to 70 wt %, and a polysiloxane-polycarbonate copolymer in amounts of about 5 to about 30 wt %, based on the total weight of the flame retardant composition produces an effective combination of flame retardancy, flow properties and impact strength.
From the Tables 4-8 above, it may be seen that the flame retardant compositions display a probability of a first time pass of 90% or greater, specifically 92% or greater, specifically 94% or greater, and more specifically 99% or greater to achieve a flame retardancy of V-0 at a sample thickness of at least 0.8 millimeters when tested per a UL-94 protocol.
In another embodiment, the compositions display an impact strength of 50 to 80 kilojoules per square meter, specifically 52 to 65 kilojoules per square meter when tested as per ASTM D 256 at 23° C., a Vicat softening point of greater than or equal to 130° C., specifically greater than or equal to 135° C., when measured as per B120, and a flame out time of less than 60 seconds, specifically less than or equal to 50 seconds, when tested as per a UL-94 protocol
In one embodiment, the flame retardant composition displays an impact strength of 50 to 80 kilojoules per square meter when tested as per ASTM D 256 at 23° C., a probability of a first time pass of 90% or greater to achieve a flame retardancy of V-0 at a sample thickness of at least 0.8 millimeters when tested per a UL-94 protocol; a Vicat softening point of greater than or equal to 130° C., when measured as per B120, and a flame out time of less than 50 seconds when measured as per a UL-94 protocol.
Example 2This example was conducted to demonstrate that the disclosed flame retardant composition can achieve a flame retardancy of 5VA at a sample thickness of 2.0 millimeters. Polycarbonate resins are used in many significant commercial applications. Polycarbonate resins are inherently flammable and, when burning, hot melt material could drip with flame causing other materials lying in the vicinity of the polycarbonate to catch fire as well. Thus, in order to safely utilize polycarbonates in many commercial applications, it is desirable to include additives which retard the flammability of the material and to reduce dripping. Polycarbonate products very rarely get a 5VA rating @ 2 mm sample thickness.
This example utilizes a phenoxyphosphazene flame retardant, a polycarbonate composition that comprises a polycarbonate homopolymer and a polysiloxane-carbonate copolymer, with talc as the synergist. This exemplary composition displays a flame retardancy rating of 5VA at a sample thickness of 2.0 mm. The ingredients are shown in the Table 9. The compounding conditions are shown in the Table 10, while molding conditions are shown in Table 11.
Table 10 shows the extrusion conditions, while Table 11 shows molding conditions.
Properties of the thermoplastic compositions were determined herein as follows. Melt volume rate (MVR) and melt flow rate (MFR) were determined at 300° C. under load of 1.2 kg according to ASTM D 1238. UL-94 5VA Testing was conducted with the flame bars being conditioned for 48 hours at room temperature and 50% relative humidity, and 70° C. for 168 hours.
A series of comparative compositions are shown in the Tables 12 and 13 below. Tables 12 and 13 reflect attempts to vary the composition to get a flame retardancy of 5VA at sample thicknesses of 2.2 millimeters. In the Table 12, a flame retardant FP110 commercially available from Fushimi Pharmaceutical Co., Ltd. was used, while in the Table 13, both FP110 and SPB-100 commercially available from Otsuka was used. In the Table 13, it may be seen that the phosphazene compound FP110 was used in some compositions, while the phosphazene compound SPB-100 was used in other compositions.
As may be seen in the Table 12, it may be seen that the comparative formulation comprising BPADP does not even achieve 5VB at a sample thickness of 2.2 millimeters (mm) (See Ex. #17-70° C. after 168 hours of aging). The formulations comprising the opaque polysiloxane-carbonate copolymer with the flame retardant i.e., the phenoxyphosphazene compound (i.e., FP110) and comprising in addition the polycarbonate, the talc and TSAN displays an ability to pass a flame retardancy test at 5VB for a sample thickness of 2.2 mm (See the flame retardancy results at 70° C. after 168 hours of aging). The compositions (Sample #s 18-22) however, cannot pass a flame retardancy test at a 5VA rating. In order to pass 5VA at a sample thickness of 2.2 mm, the effect of TSAN, talc and the opaque polysiloxane-carbonate copolymer on 5VB and 5VA were studied (see Table 13 below). The results show that while TSAN is helpful in achieving 5VB, it renders it difficult for the composition to pass 5VA at a sample thickness of 2.2 mm (See Ex. #23 and, #27). When TSAN is not used, even increasing the weight percentage the opaque polysiloxane-carbonate copolymer make it difficult to achieve 5VB at a sample thickness of 2.2 mm.
Table 13 below uses a second phosphazene compound SPB-100 in lieu of FP110. The use of SPB-100 facilitates the development of a material that displays a flame retardancy of 5VA in a flame retardancy test. In order to pass 5VA @ 2.2 mm, a silicone oil SFR-100 was used. As shown in Table 6, the flame retardant composition comprising SPB-100 and SFR-100 can achieve a flame retardancy of 5VA @ 2.2 mm sample thickness. Furthermore, with the help of SFR-100, a formulation containing 0.05% TSAN can also achieve a flame retardancy of 5VA @ 2.2 mm sample thickness.
From the Tables 12 and 13 above, it may be seen that while the flame retardant FP110 facilitates the development of a flame retardancy of 5VB at a sample thickness of 2.2 millimeters (when TSAN is absent from the composition), the use of SPB-100 facilitates the development of a flame retardancy of 5VA at a sample thickness of 2.2 millimeters, when TSAN is absent and when the sample is aged at 70° C. for 168 hours.
In order to achieve a flame retardancy of 5VA at a thickness of 2.2 millimeters, a silicone compound that comprises silicone oil endcapped with trimethylsilane (SFR-100) is added to the flame retardant composition. SFR100 is commercially available from Momentive and is a high viscosity silicone fluid comprising a combination of a linear silicone fluid, and a silicone resin that is solubilized in the fluid. The resulting silicone fluid is clear and colorless. The results are shown in the Table 14 below.
From the Table 14 it may be seen that the addition of the silicone oil is amounts of 0.5 to 2 wt %, based on the total weight of the flame retardant, promotes the achievement of a flame retardancy of 5VA at sample thickness of 2.2 millimeters (see results at 23° C., when aged for 28 hours and 70° C., when aged for 168 hours). Example #33 in the Table 14 also shows that the addition of TSAN in amounts of 0.5 wt % does not retard the development of a flame retardancy of 5VA.
Table 15 displays other combinations that can facilitate the achievement of 5VA in flame retardant compositions that have a thickness of 2.0 millimeters. In the Table 15, brominated polycarbonate and carbon black were added to the polycarbonate containing the silicone compound and the phosphazene compound.
As shown in Table 15 below, a flame retardant composition comprising phenoxyphosphazene, the opaque polysiloxane-carbonate copolymer, talc and the silicone compound can pass 5VA @ 2 mm. From the table it can also be seen that the addition of brominated polycarbonate and carbon black can also facilitate the achievement of 5VA at a sample thickness of 2 mm.
The composition disclosed herein may be advantageously used to manufacture a variety of different articles such as computer housings, housings for electronic goods such as televisions, cell phones, tablet computers, automotive parts such as interior body panels, parts for aircraft, and the like.
It is to be noted that all ranges detailed herein include the endpoints. Numerical values from different ranges are combinable.
The transition term comprising encompasses the transition terms “consisting of and “consisting essentially of.”
The term “and/or” includes both “and” as well as “or.” For example, “A and/or B” is interpreted to be A, B, or A and B.
While the invention has been described with reference to some embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims
1. A flame retardant composition comprising:
- 20 to 90 weight percent of a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and
- 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on a total weight of the flame retardant composition.
2. The flame retardant composition of claim 1, where the post-consumer recycle polycarbonate is present in an amount of 20 to 60 weight percent based on the total weight of the flame retardant composition.
3. The flame retardant composition of claim 1, where the post-consumer recycle polycarbonate comprises polyester in an amount of 0.05 to 1 wt %, based on a total weight of the post-consumer recycle polycarbonate.
4. The flame retardant composition of claim 1, where the polysiloxane-carbonate copolymer comprises 15 to 25 weight percent polysiloxane based on the total weight of the flame retardant composition, and wherein the polysiloxane has a molecular weight of greater than 30,000 Daltons.
5. The flame retardant composition of claim 1, where the polycarbonate composition further comprises 2 to 30 weight percent of a copolycarbonate derived from a dihydroxy compound having a structure of at least one of formula (9), formula (10), or formula (11):
- where the weight percent is based on the total weight of the flame retardant composition.
6. The flame retardant composition of claim 1, comprising 2 to 10 weight percent of the phosphazene compound.
7. The flame retardant polycarbonate composition of claim 1, where the phosphazene compound has the structure
- where m represents an integer of 3 to 25, R1 and R2 are the same or different and are independently a hydrogen, a hydroxyl, a C7-30 aryl, a C1-12 alkoxy, or a C1-12 alkyl.
8. The flame retardant composition of claim 1, where the phosphazene compound is phenoxy cyclotriphosphazene, octaphenoxy cyclotetraphosphazene, decaphenoxy cyclopentaphosphazene, or a combination comprising at least one of the foregoing phosphazene compounds.
9. The flame retardant composition of claim 1, where the phosphazene compound has the structure:
- where X1 represents a —N═P(OPh)3 group or a —N═P(O)OPh group, Y1 represents a —P(OPh)4 group or a —P(O)(OPh)2 group, Ph represents a phenyl group, n represents an integer from 3 to 10000, R1 and R2 are the same or different and are independently a hydrogen, a hydroxyl, a C7-30 aryl, a C1-12 alkoxy, or a C1-12 alkyl.
10. The flame retardant composition of claim 1, where the phosphazene compound is a crosslinked phenoxyphosphazene.
11. The flame retardant composition of claim 1, where the phosphazene compound has a structure
- where R1 to R6 can be the same of different and can be an aryl group, an aralkyl group, a C1-12 alkoxy, a C1-12 alkyl, or a combination thereof.
12. The flame retardant composition of claim 1, where the phosphazene compound has a structure
13. The flame retardant composition of claim 1, further comprising a pigment in an amount of 0.2 to 15 weight percent, based on the total weight of the flame retardant composition.
14. The flame retardant composition of claim 1, where the pigment comprises titanium dioxide or carbon black.
15. The flame retardant composition of claim 1, displaying a probability of a first time pass of 90% or greater to achieve a flame retardancy of V-0 at a sample thickness of at least 0.8 millimeters when tested per a UL-94 protocol.
16. The flame retardant composition of claim 1, displaying an impact strength of 50 to 80 kilojoules per square meter when tested as per ASTM D 256 at 23° C., a Vicat softening point of greater than or equal to 130° C., when measured as per B120, and a flame out time of less than 50 seconds.
17. The flame retardant composition of claim 1, displaying an impact strength of 50 to 80 kilojoules per square meter when tested as per ASTM D 256 at 23° C., a probability of a first time pass of 90% or greater to achieve a flame retardancy of V-0 at a sample thickness of at least 0.8 millimeters when tested per a UL-94 protocol; a Vicat softening point of greater than or equal to 130° C., when measured as per B120, and a flame out time of less than 50 seconds.
18. A method of manufacturing a flame retardant composition:
- blending 20 to 90 weight percent of a polycarbonate composition; where the polycarbonate composition comprises a post-consumer recycle polycarbonate and a polysiloxane-carbonate copolymer; and 1 to 20 weight percent of a phosphazene compound to form the flame retardant composition; where all weight percents are based on a total weight of the flame retardant composition; and
- extruding the flame retardant composition.
19. The method of claim 18, further comprising blending 2 to 30 weight percent of a copolycarbonate derived from a dihydroxy compound having a structure of at least one of formula (9), formula (10), or formula (11):
- where the weight percent is based on the total weight of the flame retardant composition.
20. The method of claim 18, further comprising blending a pigment in an amount of 0.2 to 15 weight percent, based on the total weight of the flame retardant composition
21. The method of claim 18, further comprising molding the flame retardant composition.
22. A flame retardant composition comprising:
- 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer;
- 0.5 to 10 weight percent of a silicone oil; and
- 1 to 20 weight percent of a phosphazene compound; where all weight percents are based on the total weight of the flame retardant composition; where the composition displays a flame retardancy of 5VA at a thickness of 2.0 millimeters or greater; when tested as per a UL-94 protocol.
23. The flame retardant composition of claim 22, where the polycarbonate composition further comprises a polycarbonate homopolymer having a weight average molecular weight of 15,000 to 40,000 Daltons.
24. The flame retardant composition of claim 22, where the polysiloxane-carbonate copolymer is present in amounts of about 5 to about 27 wt %, based on the total weight of the flame retardant composition.
25. The flame retardant composition of claim 23, where the polysiloxane-carbonate copolymer comprises 15 to 25 weight percent of polysiloxane based on the total weight of the polysiloxane-carbonate copolymer, and wherein the polysiloxane has a molecular weight of greater than 30,000 Daltons.
26. The flame retardant composition of claim 22, where the polysiloxane-carbonate copolymer comprises 4 to 10 weight percent of a polysiloxane based on the total weight of the polysiloxane-carbonate copolymer; and wherein the polysiloxane has a molecular weight of 25,000 to 30,000 Daltons.
27. The flame retardant composition of claim 22, further comprising an anti-drip agent in an amount of 1 to 10 weight percent; based on the total weight of the flame retardant composition; where the anti-drip agent is a fluorinated polyolefin or polytetrafluoroethylene.
28. The flame retardant composition of claim 22, where the flame retardant composition comprises a mineral filler.
29. The flame retardant composition of claim 28, where the mineral filler comprises talc.
30. The flame retardant composition of claim 22, where the silicone oil comprises a polysiloxane polymer endcapped with trimethylsilane; where the silicone oil has a viscosity at 25° C. of 20,000 to 900,000 square millimeter per second.
31. The flame retardant composition of claim 22, comprising 3 to 10 weight percent of the phosphazene compound.
32. The flame retardant composition of claim 31, where the phosphazene compound has the structure:
- where m represents an integer of 3 to 25, R1 and R2 are the same or different and are independently a hydrogen, a hydroxyl, a C7-30 aryl group, a C1-12 alkoxy, or a C1-12 alkyl.
33. The flame retardant composition of claim 22, where the phosphazene compound is phenoxy cyclotriphosphazene, octaphenoxy cyclotetraphosphazene, decaphenoxy cyclopentaphosphazene, or a combination comprising at least one of the foregoing phosphazene compounds.
34. The flame retardant composition of claim 31, where the phosphazene compound has the structure:
- where X′ represents a —N═P(OPh)3 group or a —N═P(O)OPh group, Y1 represents a —P(OPh)4 group or a —P(O)(OPh)2 group, Ph represents a phenyl group, n represents an integer from 3 to 10000, R1 and R2 are the same or different and are independently a hydrogen, a hydroxyl, a C7-30 aryl, a C1-12 alkoxy, or a C1-12 alkyl.
35. The flame retardant composition of claim 31, where the phosphazene compound is a crosslinked phenoxyphosphazene.
36. The flame retardant composition of claim 31, where the phosphazene compound has a structure:
- where R1 to R6 can be the same of different and can be an aryl, an aralkyl group, a C1-12 alkoxy, a C1-12 alkyl, or a combination thereof.
37. The flame retardant composition of claim 31, where the phosphazene compound has a structure:
38. The flame retardant composition of claim 31, having a melt volume rate of greater than or equal to 4.00 cm3/10 minutes when tested as per ASTM D1238 and a flame out time of less than 20 seconds after being aged for 48 hours when tested as per a UL-94 protocol.
39. A method of manufacturing a flame retardant composition comprising:
- blending 50 to 90 wt % of a polycarbonate composition; where the polycarbonate composition comprises a polysiloxane-carbonate copolymer; 0.5 to 10 weight percent of a silicone oil; and 1 to 20 weight percent of a phosphazene compound to form the flame retardant composition; where all weight percents are based on the total weight of the flame retardant composition; where the composition displays a flame retardancy of 5VA at a thickness of 20 millimeters or greater; when tested as per a UL-94 protocol; and
- extruding the composition.
40. The method of claim 39, further comprising molding the composition.
41. An article manufactured from the composition of claim 1.
42. An article manufactured from the composition of claim 22.
Type: Application
Filed: May 23, 2013
Publication Date: Nov 28, 2013
Inventors: Liang Wen (Shanghai), Wei Shan (Shanghai), Mingfeng Li (Shanghai), Tong Wu (Shanghai)
Application Number: 13/901,300
