FILLED POLYURETHANE COMPOSITES WITH SIZE-GRADED FILLERS
Polyurethane composites and methods of preparing polyurethane composites are described herein. The polyurethane composite can comprise (a) a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols; (b) fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns; and (c) a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from greater than 250 microns to 10 mm. The coarse filler material can be present in the composite in an amount of from 1% to 40% by weight, based on the total weight of the composite. The weight ratio of the fly ash to the coarse filler material can be from 9:1 to 200:1.
This disclosure relates generally to polyurethane composites, more particularly, to the use of size-graded fillers including a fine filler such as fly ash and a coarse filler in polyurethane composites.
BACKGROUND OF THE DISCLOSUREPolymeric composites that contain organic and/or inorganic filler materials have become desirable for a variety of uses because of their excellent mechanical properties and weathering stability. In general, the superior properties of the polymeric composites are achieved through use of the polymer as the matrix material that acts as a glue with enhanced flexural properties or as a fibrous component providing reinforcement and improved tensile properties. The inorganic material imparts various properties of rigidity, toughness, hardness, optical appearance and interaction with electromagnetic radiation, density, and many other physical and chemical attributes. A proper blend of polymeric and inorganic materials provides for a composite with optimal properties at a desirably low cost.
Polyurethane composites composed of a polyurethane binder and fly ash filler with glass fiber reinforcement have been shown to be very useful. Specific uses of such composites include applications as interior and exterior cladding on buildings. However, one challenge for highly-filled filler-polyurethane composites is that it is very difficult to improve the mechanical performance of such materials without incurring significant costs. Another challenge is that there exists a threshold for the total content of the fly ash filler and reinforcement materials that can be incorporated into the composites. In particular, raising the content of fly ash filler and/or reinforcement materials can greatly increase the viscosity of the polyurethane mixture and eventually make such systems difficult to process and manufacture into gross and net shapes. There is a need to improve the properties of filled composites. The compositions and methods described herein address these and other needs.
SUMMARY OF THE DISCLOSUREPolyurethane composites and methods of preparing polyurethane composites are described herein. The polyurethane composites can comprise (a) a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols; (b) fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns; and (c) a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from greater than 250 microns to 10 mm.
The polyurethane can be present in an amount of from 15% to 60% by weight, based on the total weight of the composite. In some examples, the polyurethane can be present in an amount of from 15% to 40% by weight, based on the total weight of the composite. In some embodiments, 50% or more of the one or more polyols can have a hydroxyl number of 250 mg KOH/g or greater. In some embodiments, 50% or more of the one or more polyols can include 75% or more primary hydroxyl groups based on the total number of hydroxyl groups in the polyol. The one or more polyols can comprise an aromatic polyester polyol, an aromatic polyether polyol, or a combination thereof.
The coarse filler material can be present in the composite in an amount of from 1% to 40% (for example, 1 to 30%) by weight, based on the total weight of the composite. In some embodiments, 80% or greater by weight of the coarse filler material comprises filler particles having particle size of from greater than 250 microns to 1 mm, for example, 300 microns to 500 microns. Suitable coarse filler materials can include silica sand, silica fume, cement, slag, metakaolin, talc, mica, wollastonite, limestone, calcium carbonate, perlite, clay, shale, ceramic, glass, seed hull, organic waste, or combinations thereof. In some examples, the coarse filler material includes expanded glass or sand. In some embodiments, the coarse filler material can be coated with an agent selected from surfactants, bonding agents, pigments, and combinations thereof.
Fly ash can be present in the composite in an amount of from 20% to 90% (for example, 20% to 80% or 50% to 80%) by weight, based on the total weight of the composite. In some examples, fly ash can be present in the composite in an amount of from 20% to 80% or 50% to 80% by weight, based on the total weight of the composite. In some embodiments, the fly ash can be Class C fly ash. In some examples, the fly ash can have a particle size distribution comprising a first mode having a median particle diameter from 0.3 micron to 1 micron, a second mode having a median particle diameter from 10 microns to 25 microns, and a third mode having a median particle diameter from 40 microns to 80 microns.
The weight ratio of the fly ash to the coarse filler material can be from 9:1 to 200:1, such as from 9:1 to 150:1.
The polyurethane composite can further comprise a fiber material. The fiber material can be present in an amount of from 1% to 20% by weight, based on the total weight of the composite. Examples of suitable fiber materials include polyacrylonitrile fibers, polyamide fibers, polyester fibers, glass fibers, mineral wool, rayon, cellulose, wood fibers, saw dust, wood shavings, cotton, lint, polypropylene fibers, polyethylene fibers, polyacrylic fibers, or combinations thereof. In some embodiments, the fiber material can include a plurality of glass fibers. The glass fibers can have an average length of 1 mm or greater, for example, from 1.5 mm to 30 mm.
In some embodiments, the polyurethane composite can be foamed. The density of the polyurethane composites described herein can be from 5 lb/ft3 to 70 lb/ft3. The composite can have a flexural strength of 300 psi or greater, as measured by ASTM C1185.
Building materials comprising the polyurethane composites described herein are disclosed. The building material can include siding materials, carpet backings, building panels, sheets, architectural moldings, sound barriers, thermal barriers, insulation, wall board, ceiling tiles, ceiling boards, soffit, and roofing materials.
Methods of making the polyurethane composites described herein are disclosed. The method can include (a) mixing (1) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, (2) one or more polyols, (3) fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns, and (4) a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from 250 microns to 10 mm to form a mixture; and (b) allowing the one or more isocyanates and the one or more polyols to react in the presence of the fly ash and the coarse filler material to form the polyurethane composite. In some embodiments, the polyurethane mixture can further include a catalyst.
Polyurethane composites and methods of preparing polyurethane composites are described herein. The polyurethane composites can comprise a polyurethane formed using highly reactive systems such as highly reactive polyols, isocyanates, or both.
Isocyanates suitable for use in the polyurethane composite described herein include one or more monomeric or oligomeric poly- or di-isocyanates. The monomeric or oligomeric poly- or di-isocyanate include aromatic diisocyanates and polyisocyanates. The isocyanates can also be blocked isocyanates or pre-polymer isocyanates. An example of a useful diisocyanate is methylene diphenyl diisocyanate (MDI). Useful MDI's include MDI monomers, MDI oligomers, and mixtures thereof.
Further examples of useful isocyanates include those having NCO (i.e., the reactive group of an isocyanate) contents ranging from about 25% to about 35% by weight. Examples of useful isocyanates are found, for example, in Polyurethane Handbook: Chemistry, Raw Materials, Processing Application, Properties, 2nd Edition, Ed: Gunter Oertel; Hanser/Gardner Publications, Inc., Cincinnati, Ohio, which is herein incorporated by reference. Suitable examples of aromatic polyisocyanates include 2,4- or 2,6-toluene diisocyanate, including mixtures thereof; p-phenylene diisocyanate; tetramethylene and hexamethylene diisocyanates; 4,4-dicyclohexylmethane diisocyanate; isophorone diisocyanate; 4,4-phenylmethane diisocyanate; polymethylene polyphenylisocyanate; and mixtures thereof. In addition, triisocyanates may be used, for example, 4,4,4-triphenylmethane triisocyanate; 1,2,4-benzene triisocyanate; polymethylene polyphenyl polyisocyanate; methylene polyphenyl polyisocyanate; and mixtures thereof. Suitable blocked isocyanates are formed by the treatment of the isocyanates described herein with a blocking agent (e.g., diethyl malonate, 3,5-dimethylpyrazole, methylethylketoxime, and caprolactam). Isocyanates are commercially available, for example, from Bayer Corporation (Pittsburgh, Pa.) under the trademarks MONDUR and DESMODUR. Other examples of suitable isocyanates include MONDUR MR Light (Bayer Corporation; Pittsburgh, Pa.), PAPI 27 (Dow Chemical Company; Midland, Mich.), Lupranate M20 (BASF Corporation; Florham Park, N.J.), Lupranate M70L (BASF Corporation; Florham Park, N.J.), Rubinate M (Huntsman Polyurethanes; Geismar, La.), Econate 31 (Ecopur Industries), and derivatives thereof.
The average functionality of isocyanates useful with the composites described herein can be between about 1.5 to about 5. Further, examples of useful isocyanates include isocyanates with an average functionality of about 2 to about 4.5, about 2.2 to about 4, about 2.4 to about 3.7, about 2.6 to about 3.4, and about 2.8 to about 3.2.
The one or more polyols for use in the polyurethane composite can include polyester polyols, polyether polyols, or combinations thereof. In some embodiments, the one or more polyols can include 50% or more of one or more highly reactive (i.e., first) polyols. For example, the one or more polyols can include greater than 55%, greater than 60%, greater than 65%, greater than 70%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, greater than 95%, or 100% of one or more highly reactive polyols.
In some embodiments, the one or more highly reactive polyols can include polyols having a hydroxyl number of greater than 250. For example, the hydroxyl number can be greater than 275, greater than 300, greater than 325, greater than 350, greater than 375, greater than 400, greater than 425, greater than 450, greater than 475, greater than 500, greater than 525, greater than 550, greater than 575, greater than 600, greater than 625, greater than 650, greater than 675, greater than 700, greater than 725, or greater than 750.
In some embodiments, the one or more highly reactive polyols can include polyols having a primary hydroxyl number of greater than 250. As used herein, the primary hydroxyl number is defined as the hydroxyl number multiplied by the percentage of primary hydroxyl groups based on the total number of hydroxyl groups in the polyol. For example, the primary hydroxyl number can be greater than 255, greater than 260, greater than 265, greater than 270, greater than 275, greater than 280, greater than 285, greater than 290, or greater than 295.
In some embodiments, the one or more highly reactive polyols include a large number of primary hydroxyl groups (e.g. 75% or more) based on the total number of hydroxyl groups in the polyol. For example, the highly reactive polyols can include 80% or more, 85% or more, 90% or more, 95% or more, or 100% of primary hydroxyl groups. The number of primary hydroxyl groups can be determined using fluorine NMR spectroscopy as described in ASTM D4273, which is hereby incorporated by reference in its entirety.
In some embodiments, the one or more highly reactive polyols can include a Mannich polyol. Mannich polyols are the condensation product of a substituted or unsubstituted phenol, an alkanolamine, and formaldehyde. Mannich polyols can be prepared using methods known in the art. For example, Mannich polyols can be prepared by premixing the phenolic compound with a desired amount of the alkanolamine, and then slowly adding formaldehyde to the mixture at a temperature below the temperature of Novolak formation. At the end of the reaction, water is stripped from the reaction mixture to provide a Mannich base. See, for example, U.S. Pat. No. 4,883,826, which is incorporated herein by reference in its entirety. The Mannich base can then be alkoxylated to provide a Mannich polyol.
The substituted or unsubstituted phenol can include one or more phenolic hydroxyl groups. In certain embodiments, the substituted or unsubstituted phenol includes a single hydroxyl group bound to a carbon in an aromatic ring. The phenol can be substituted with substituents which do not undesirably react under the conditions of the Mannich condensation reaction, a subsequent alkoxylation reaction (if performed), or the preparation of polyurethanes from the final product. Examples of suitable substituents include alkyl (e.g., a C1-C18 alkyl, or a C1-C12 alkyl), aryl, alkoxy, phenoxy, halogen, and nitro groups.
Examples of suitable substituted or unsubstituted phenols that can be used to form Mannich polyols include phenol, o-, p-, or m-cresols, ethylphenol, nonylphenol, dodecylphenol, p-phenylphenol, various bisphenols including 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), β-naphthol, β-hydroxyanthracene, p-chlorophenol, o-bromophenol, 2,6-dichlorophenol, p-nitrophenol, 4- or 2-nitro-6-phenylphenol, 2-nitro-6- or 4-methylphenol, 3,5-dimethylphenol, p-isopropylphenol, 2-bromo-6-cyclohexylphenol, and combinations thereof. In some embodiments, the Mannich polyol is derived from phenol or a monoalkyl phenols (e.g., a para-alkyl phenols). In some embodiments, the Mannich polyol is derived from a substituted or unsubstituted phenol selected from the group consisting of phenol, para-n-nonylphenol, and combinations thereof.
The alkanolamine used to produce the Mannich polyol can include a monoalkanolamine, a dialkanolamine, or combinations thereof. Examples of suitable monoalkanolamines include methylethanolamine, ethylethanolamine, methylisopropanolamine, ethylisopropanolamine, methyl-2-hydroxybutylamine, phenylethanolamine, ethanolamine, isopropanolamine, and combinations thereof. Exemplary dialkanolamines include diisopropanolamine, ethanolisopropanolamine, ethanol-2-hydroxybutylamine, isopropanol-2-hydroxybutylamine, isopropanol-2-hydroxyhexylamine, ethanol-2-hydroxyhexylamine, and combinations thereof. In certain embodiments, the alkanolamine is selected from the group consisting of diethanolamine, diisopropanolamine, and combinations thereof.
Any suitable alkylene oxide or combination of alkylene oxides can be used to form the Mannich polyol. In some embodiments, the alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof. In certain embodiments, the Mannich polyol is alkoxylated with from 100% to about 80% propylene oxide and from 0 to about 20 wt. % ethylene oxide.
Mannich polyols are known in the art, and include, for example, ethylene and propylene oxide-capped Mannich polyols sold under the trade names CARPOL® MX-425 and CARPOL® MX-470 (Carpenter Co., Richmond, Va.).
In some embodiments, the one or more first polyols can include an aromatic polyester polyol, an aromatic polyether polyol, or a combination thereof. In some embodiments, the one or more first polyols include an aromatic polyester polyol such as those sold under the TEROL® trademark (e.g., TEROL® 198).
Examples of highly reactive polyols also include Pel-Soy 744 and Pel-Soy P-750, soybean oil based polyols commercially available from Pelron Corporation; Agrol Diamond, a soybean oil based polyol commercially available from BioBased Technologies; Ecopol 122, Ecopol 131 and Ecopol 132, soybean oil polyols formed using polyethylene terephthalate and commercially available from Ecopur Industries; Stepanpol PD-110 LV and PS 2352, polyols based on soybean oil, diethylene glycol and phthallic anhydride and commercially available from Stepan Company; Voranol 280, 360 and WR2000, polyether polyols commercially available from Dow Chemical Company; Honey Bee HB-530, a soybean oil-based polyol commercially available from MCPU Polymer Engineering; Renewpol, commercially available from Styrotech Industries (Brooklyn Park, Minn.); JeffAdd B 650, a 65% bio-based content (using ASTM D6866-06) additive based on soybean oil commercially available from Huntsman Polyurethanes; Jeffol SG 360, a sucrose and glycerin-based polyol commercially available from Huntsman Polyurethanes; and derivatives thereof. For example, Ecopol 131 is a highly reactive aromatic polyester polyol comprising 80% primary hydroxyl groups, a hydroxyl number of 360-380 mg KOH/g, i.e., and a primary hydroxyl number of 288-304 mg KOH/g.
The one or more polyols for use in the polyurethane composites can include one or more plant-based polyols. In some embodiments, the plant-based polyols are highly reactive polyols. The one or more plant-based polyols useful in the polyurethane composites can include polyols containing ester groups that are derived from plant-based fats and oils. Accordingly, the one or more plant-based polyols can contain structural elements of fatty acids and fatty alcohols. Starting materials for the plant-based polyols of the polyurethane component can include fats and/or oils of plant-based origin with preferably unsaturated fatty acid residues. The one or more plant-based polyols useful with the polyurethane composites include, for example, castor oil, coconut oil, corn oil, cottonseed oil, lesquerella oil, linseed oil, olive oil, palm oil, palm kernel oil, peanut oil, sunflower oil, tall oil, and mixtures thereof. In some embodiments, the one or more polyols are non-plant-based polyols.
In some embodiments, the one or more polyols include a less reactive polyol. For example, the polyurethane composite can be produced from one or more less reactive polyols in addition to one or more highly reactive polyols. Less reactive polyols can have lower hydroxyl numbers, lower numbers of primary hydroxyl groups and/or lower primary hydroxyl numbers than the highly reactive polyols. In some embodiments, the less reactive polyols can have hydroxyl numbers of less than 250, less than 225, less than 200, less than 175, less than 150, less than 125, less than 100, less than 80, less than 60, less than 40, or even less than 20. In some embodiments, the less reactive polyols have about 50% or less primary hydroxyl groups, about 40% or less primary hydroxyl groups, about 30% or less primary hydroxyl groups, about 20% or less primary hydroxyl groups, or even about 10% or less primary hydroxyl groups. In some embodiments, the less reactive polyols can have primary hydroxyl numbers of less than about 220, less than about 200, less than about 180, less than about 160, less than about 140, less than about 120, less than about 100, less than about 80, less than about 60, less than about 40, or even less than about 20. Suitable less reactive polyols include castor oil; Stepanpol PS-2052A (commercially available from the Stepan Company); Agrol 2.0, 3.6, 4.3, 5.6 and 7.0 (plant-based polyols commercially available from BioBased Technologies); Ecopol 123 and Ecopol 124, which are commercially available from Ecopur Industries; Honey Bee HB-150 and HB-230, soybean oil-based polyols commercially available from MCPU Polymer Engineering; Terol 1154, commercially available from Oxid (Houston, Tex.); Multranol 3900, Multranol 3901, Arcol 11-34, Arcol 24-32, Arcol 31-28, Arcol E-351, Arcol LHT-42, and Arcol LHT-112, commercially available from Bayer; and Voranol 220-028, 220-094, 220-110N, 222-056, 232-027, 232-034, and 232-035, commercially available from Dow.
The one or more polyol can include 50% or less of one or more less reactive polyols in addition to the one or more highly reactive polyols. For example, the one or more polyol can include less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, or less than 5%, of one or more less reactive polyols.
The one or more polyol for use in the disclosure can have an average functionality of 1.5 to 8.0, 1.6 to 6.0, 1.8 to 4.0, 2.5 to 3.5, or 2.6 to 3.1. The average hydroxyl number values (as measured in units of mg KOH/g) for the one or more polyol can be from about 100 to 600, 150 to 550, 200 to 500, 250 to 440, 300 to 415, and 340 to 400.
The polyurethane composites can include more than one type of polyol. The one or more polyols can be combined in various percentages, e.g., 15-40% of a less reactive polyol and 60-85% of a highly reactive polyol.
The polyurethane systems used to form the composite materials described herein can include one or more additional isocyanate-reactive monomers in addition to the one or more polyol. The one or more additional isocyanate-reactive monomers can include, for example, amine and optionally hydroxyl groups.
In some embodiments, the one or more additional isocyanate-reactive monomers can include a polyamine. The first isocyanate-reactive monomer can comprise a polyamine. Any suitable polyamine can be used. Suitable polyamines can correspond to the polyols described herein (for example, a polyester polyol or a polyether polyol), with the exception that the terminal hydroxy groups are converted to amino groups, for example by amination or by reacting the hydroxy groups with a diisocyanate and subsequently hydrolyzing the terminal isocyanate group to an amino group. By way of example, the polyamine can be polyether polyamine, such as polyoxyalkylene diamine or polyoxyalkylene triamine. Polyether polyamines are known in the art, and can be prepared by methods including those described in U.S. Pat. No. 3,236,895 to Lee and Winfrey. Exemplary polyoxyalkylene diamines are commercially available, for example, from Huntsman Corporation under the trade names Jeffamine® D-230, Jeffamine® D-400 and Jeffamine® D-2000. Exemplary polyoxyalkylene triamines are commercially available, for example, from Huntsman Corporation under the trade names Jeffamine® T-403, Jeffamine® T-3000, and Jeffamine® T-5000.
In some embodiments, the additional isocyanate-reactive monomer can include an alkanolamine. The alkanolamine can be a dialkanolamine, a trialkanolamine, or a combination thereof. Suitable dialkanolamines include dialkanolamines which include two hydroxy-substituted C1-C12 alkyl groups (e.g., two hydroxy-substituted C1-C8 alkyl groups, or two hydroxy-substituted C1-C6 alkyl groups). The two hydroxy-substituted alkyl groups can be branched or linear, and can be of identical or different chemical composition. Examples of suitable dialkanolamines include diethanolamine, diisopropanolamine, ethanolisopropanolamine, ethanol-2-hydroxybutylamine, isopropanol-2-hydroxybutylamine, isopropanol-2-hydroxyhexylamine, ethanol-2-hydroxyhexylamine, and combinations thereof. Suitable trialkanolamines include trialkanolamines which include three hydroxy-substituted C1-C12 alkyl groups (e.g., three hydroxy-substituted C1-C8 alkyl groups, or three hydroxy-substituted C1-C6 alkyl groups). The three hydroxy-substituted alkyl groups can be branched or linear, and can be of identical or different chemical composition. Examples of suitable trialkanolamines include triisopropanolamine (TIPA), triethanolamine, N,N-bis(2-hydroxyethyl)-N-(2-hydroxypropyl)amine (DEIPA), N,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine (EDIPA), tris(2-hydroxybutyl)amine, hydroxyethyl di(hydroxypropyl)amine, hydroxypropyl di(hydroxyethyl)amine, tri(hydroxypropyl)amine, hydroxyethyl di(hydroxy-n-butyl)amine, hydroxybutyl di(hydroxypropyl)amine, and combinations thereof.
In some embodiments, the additional isocyanate-reactive monomer can comprise an adduct of an alkanolamine described above with an alkylene oxide. The resulting amine-containing polyols can be referred to as alkylene oxide-capped alkanolamines. Alkylene oxide-capped alkanolamines can be formed by reacting a suitable alkanolamine with a desired number of moles of an alkylene oxide. Any suitable alkylene oxide or combination of alkylene oxides can be used to cap the alkanolamine. In some embodiments, the alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof. Alkylene oxide-capped alkanolamines are known in the art, and include, for example, propylene oxide-capped triethanolamine sold under the trade names CARPOL® TEAP-265 and CARPOL® TEAP-335 (Carpenter Co., Richmond, Va.).
In some embodiments, the additional isocyanate-reactive monomer can include an alkoxylated polyamine (i.e., alkylene oxide-capped polyamines) derived from a polyamine and an alkylene oxide. Alkoxylated polyamine can be formed by reacting a suitable polyamine with a desired number of moles of an alkylene oxide. Suitable polyamines include monomeric, oligomeric, and polymeric polyamines. In some cases, the polyamines has a molecular weight of less than 1000 g/mol (e.g., less than 800 g/mol, less than 750 g/mol, less than 500 g/mol, less than 250 g/mol, or less than 200 less than 200 g/mol). Examples of suitable polyamines that can be used to form alkoxylated polyamines include ethylenediamine, 1,3-diaminopropane, putrescine, cadaverine, hexamethylenediamine, 1,2-diaminopropane, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, spermidine, spermine, norspermidine, toluene diamine, 1,2-propane-diamine, diethylenetriamine, triethylenetetramine, tetraethylene-pentamine (TEPA), pentaethylenehexamine (PEHA), and combinations thereof.
Any suitable alkylene oxide or combination of alkylene oxides can be used to cap the polyamine. In some embodiments, the alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof. Alkylene oxide-capped polyamines are known in the art, and include, for example, propylene oxide-capped ethylene diamine sold under the trade name CARPOL® EDAP-770 (Carpenter Co., Richmond, Va.) and ethylene and propylene oxide-capped ethylene diamine sold under the trade name CARPOL® EDAP-800 (Carpenter Co., Richmond, Va.).
The additional isocyanate-reactive monomer (when used) can be present in varying amounts relative the one or more polyol used to form the polyurethane. In some embodiments, the additional isocyanate-reactive monomer can be present in an amount of 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less by weight based on the weight of the one or more polyol.
As indicated herein, in the polyurethane composites, an isocyanate is reacted with a polyol (and any additional isocyanate-reactive monomers) to produce the polyurethane formulation. In general, the ratio of isocyanate groups to the total isocyanate reactive groups, such as hydroxyl groups, water and amine groups, is in the range of about 0.5:1 to about 1.5:1, which when multiplied by 100 produces an isocyanate index between 50 and 150. Additionally, the isocyanate index can be from about 80 to about 120, from about 90 to about 120, from about 100 to about 115, or from about 105 to about 110. As used herein, an isocyanate may be selected to provide a reduced isocyanate index, which can be reduced without compromising the chemical or mechanical properties of the composite material.
One or more catalysts can be added to facilitate curing and can be used to control the curing time of the polymer matrix. Examples of useful catalysts include amine-containing catalysts (such as DABCO, tetramethylbutanediamine, and diethanolamine) and tin-, mercury-, and bismuth-containing catalysts. In some embodiments, 0.01 wt % to 2 wt % catalyst or catalyst system (e.g., 0.025 wt % to 1 wt %, 0.05 wt % to 0.5 wt %, or 0.1 wt % to about 0.25 wt %) can be used based on the weight of the polyurethane composite.
The polyurethane can be present in the composite in amounts from 10% to 60% based on the weight of polyurethane composite. For example, the polyurethane can be included in an amount from 15% to 60% or 20% to 50% by weight, based on the weight of the polyurethane composite. In some embodiments, the polyurethane in the polyurethane composites can be present in an amount of 10% or greater, 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, 40% or greater, 45% or greater, 50% or greater, or 55% or greater by weight, based on the weight of polyurethane composite. In some embodiments, the polyurethane in the polyurethane composites can be present in an amount of 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, or 15% or less by weight, based on the weight of polymeric composite.
The polyurethane composites can include a particulate filler. In some examples, the particulate filler includes fly ash. Fly ash is produced from the combustion of pulverized coal in electrical power generating plants. The fly ash useful with the composite materials described herein can be Class C fly ash, Class F fly ash, or a mixture thereof. Fly ash produced by coal-fueled power plants is suitable for incorporation in the composites described herein.
In some embodiments, the particle size distribution of the fly ash can include 50% or greater of fly ash particles by weight having a diameter of from 0.2 micron to 100 microns. For example, 55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater, 80% or greater, 85% or greater, or 90% or greater of the fly ash particles by weight can have a diameter of from 0.2 micron to 100 microns. In some embodiments, 50% or greater of the fly ash can have a particle diameter of 100 microns or less, 95 microns or less, 90 microns or less, 85 microns or less, 80 microns or less, 75 microns or less, 70 microns or less, 65 microns or less, 60 microns or less, 55 microns or less, 50 microns or less, and can have a particle diameter of 0.2 microns or more, 0.3 microns or more, 0.4 microns or more, 0.5 microns or more, 0.7 microns or more, 1 micron or more, 2 microns or more, 5 microns or more, or 10 microns or more. In some examples, the 50% or greater of the fly ash can have a particle diameter of from 0.2 microns to 100 microns, 0.2 microns to 90 microns, or 0.3 microns to 80 microns, 1 to 60 microns, or 5 to 50 microns.
In some embodiments, the fly ash can have a particle size distribution with at least three modes. For example, the particle size distribution of the fly ash can be three, four, five, or more modes. Alternatively, the fly ash can be blended with another fly ash to modify the properties of the fly ash to produce a fly ash having a particle size distribution with at least three modes.
The fly ash particle size distribution can include a first mode having a median particle diameter of 2.0 microns or less. In some examples, the median particle size of the first mode can be 0.3 microns to 1.5 microns, 0.4 microns to 1 microns, or 0.5 microns to 0.8 microns (e.g., 0.7 microns). The fly ash particle size distribution can include a second mode having a median particle diameter of from 3 microns to less than 40 microns. In some examples, the median particle size of the second mode can be from 5 microns to 35 microns, 10 microns to 30 microns, or 10 microns to 25 microns. The fly ash particle size distribution can include a third mode having a median particle diameter of 40 microns or greater. In some examples, the median particle size of the third mode can be from 40 microns to less than 100 microns, for example from 40 microns to 90 microns, 40 microns to 80 microns, or from 40 microns to 75 microns. In some embodiments, the fly ash particle size distribution can include a first mode having a median particle diameter of from 0.3 microns to 1.0 micron, a second mode having a median particle diameter of from 10 microns to 25 microns, and a third mode having a median particle diameter of from 40 microns to 80 microns. In some examples, the fly ash can also include an additional ultrafine mode with a median particle diameter of from 0.05 microns to 0.2 microns.
In some embodiments, the particle size distribution can include 11-17% of the particles by volume in the first mode, 56-74% of the particles by volume in the second mode, and 12-31% of the particles by volume in the third mode. The ratio of the volume of particles in the second and third modes to the volume of particles in the first mode can be from 4.5 to 7.5.
The fly ash can be present in the polyurethane composites in amounts from 20% to 90% by weight. In some embodiments, the fly ash can be present in amounts from 35% to 80% such as from 50% to 80% or from 50% to 75% by weight. Examples of the amount of fly ash present in the composites described herein include 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90% by weight.
The particulate filler can include an additional filler material. The additional filler material can include a coarse filler material or a combination of coarse filler materials. The coarse filler material can be any natural or synthetic material, based on inorganic materials, organic materials, or combinations of both. In some embodiments, the coarse filler material can include silica sand, silica fume, cement, slag, metakaolin, talc, mica, wollastonite, limestone, calcium carbonate, perlite, clay (e.g., kaolin), shale, ceramic, glass, seed hull, organic waste, or combinations thereof. In some embodiments, the coarse filler can include an organic material, such as a recycled polymeric material. Suitable examples include pulverized polymeric foam or recycled rubber material. In some examples, the coarse filler material can include expanded glass. In other examples, the coarse filler material can include sand. In some embodiments, the coarse filler is not fly ash.
In some embodiments, 80% or greater of the coarse filler particles by weight have a particle diameter of from greater than 250 microns to 10 mm, greater than 250 microns to 5 mm, greater than 250 microns to 2 mm, greater than 250 microns to 1 mm, or 250 microns to 500 microns. For example, the coarse filler material can include 85% or greater, 90% or greater, or 95% or greater of filler particles by weight having a particle diameter of from 250 microns to 10 mm, 250 microns to 5 mm, 250 microns to 2 mm, 250 microns to 1 mm, or 250 microns to 500 microns. In some embodiments, 80% or greater of the coarse filler particles have a particle diameter of 250 microns or greater, 300 microns or greater, or 350 microns or greater, and a particle diameter of 10 mm or less, 8 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less, or 500 microns or less.
In some embodiments, the particle size distribution of the coarse filler material can include having a diameter of from 250 microns to 10 mm.
The coarse filler material can be present in the polyurethane composite in any suitable amount to confer a desirable property to the polyurethane composite. The coarse filler material can be present in the polyurethane composite in amounts from 0.1% to 50% by weight, based on the total weight of the composite. For example, the coarse filler material can be in amounts of from 1% to 40%, 1% to 30%, 1% to 20%, or 1% to 10% by weight, based on the total weight of the composite. In some embodiments, the coarse filler material can be present in the polyurethane composite in amounts of 0.1% or greater, 0.5% or greater, 1% or greater, 1.25% or greater, 1.5% or greater, 2% or greater, 3% or greater, 4% or greater, or 5% or greater by weight, based on the total weight of the composite. In some embodiments, the coarse filler material can be present in the polyurethane composite in amounts of 50% or less, 40% or less, 30% or less, 20% or less, 15% or less, 10% or less, 8% or less, or 5% or less by weight, based on the total weight of the composite.
The weight ratio of the fly ash to the coarse filler material can be 1:1 or greater. For example, the weight ratio of the fly ash to the coarse filler material can be from 1:1 to 200:1, 5:1 to 200:1, 9:1 to 200:1, 9:1 to 150:1, 9:1 to 100:1, 9:1 to 80:1, or 9:1 to 50:1. In some embodiments, the weight ratio of the fly ash to the coarse filler material can be 2:1 or greater, 5:1 or greater, 9:1 or greater, 10:1 or greater, 20:1 or greater, 30:1 or greater, 40:1 or greater, 50:1 or greater, 60:1 or greater, or 70:1 or greater. In some embodiments, the weight ratio of the fly ash to the coarse filler material can be 200:1 or less, 175:1 or less, 150:1 or less, 125:1 or less, 100:1 or less, 75:1 or less, or 50:1 or less.
In some embodiments, a fiber material can be included in the polyurethane composite, e.g., to provide increased strength, stiffness or toughness. The fiber material can be any natural or synthetic fiber material, based on inorganic materials, organic materials, or combinations of both. Fiber materials suitable for use with the polyurethane composite described herein can be present in the form of individual fibers, fabrics, rovings, or tows. Exemplary fiber materials that can be used in the polyurethane composite include mineral wool fibers such as stone wool, slag wool, or ceramic fiber wool. The mineral wool fibers can be synthetic or can be obtained from molten mineral such as lava, rock or stone. Other suitable inorganic fiber materials include basalt fibers, alumina silica fibers, aluminum oxide fibers, silica fibers, carbon fibers, metal fibers, and combinations thereof. Exemplary organic fiber materials that can be used in the polyurethane composite include hemp fibers, sisal fibers, cotton fibers, straw, reeds, or other grasses, jute, bagasse fibers, abaca fibers, flax, southern pine fibers, wood fibers, cellulose, saw dust, wood shavings, lint, vicose, leather fibers, rayon, and mixtures thereof. Other suitable organic fiber materials include synthetic fibers such as, Kevlar, viscose fibers, polyamide fibers, polyacrylonitrile fibers, Dralon® fibers, polyethylene fibers, polypropylene fibers, polyvinyl alcohol fibers, polyacrylic fibers, polyester fibers, aramid fibers, carbon fibers, or combinations thereof. In some embodiments, the polyurethane composites can include a combination of fibers that break and fibers that do not break when the composite is fractured by external stress.
The fiber material (when used) can be present in the polyurethane composites in amounts from 0.5% to 20% by weight, based on the weight of polyurethane composite. For example, the fiber material can be present in amounts from 1% to 20%, 1% to 10%, 1.5% to 8%, 2% to 6%, or 2% to 4% by weight, based on the weight of the polyurethane composite.
In some embodiments, the polyurethane composites can comprise a plurality of glass fibers as the fiber material. Glass fibers can include fibrous glass such as E-glass, C-glass, S-glass, and AR-glass fibers. In some examples, fire resistant or retardant glass fibers can be included to impart fire resistance or retarding properties to the polyurethane composites. The glass fibers can be from 1 mm to 50 mm in average length. In some examples, the glass fibers are from 1.5 mm to 30 mm, from 2 mm to 30 mm, from 3 mm to 30 mm, or from 3 mm to 15 mm in average length. In some examples, the average length of the glass fibers in the polyurethane composites can be 1 mm or greater, 1.5 mm or greater, 2 mm or greater, 3 mm or greater, 4 mm or greater, 5 mm or greater, or 6 mm or greater. In some embodiments, the average length of the glass fibers can be 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, 15 mm or less, 12 mm or less, or 10 mm or less. The glass fibers in the polyurethane composites can have any dimension of from 1 μm to 30 μm in average diameter. For example, the average diameter of the glass fibers can be 1.5 μm to 30 μm, 3 μm to 20 μm, 4 μm to 18 μm, or 5 μm to 15 μm in average diameter. The glass fibers can be provided in a random orientation or can be axially oriented.
In some embodiments, the fibers, coarse filler material, and/or the fly ash can be coated with a composition to modify their reactivity. For example, the fibers, coarse filler material, and/or the fly ash can be coated with a sizing agent. In some embodiments, the fibers, coarse filler material, and/or the fly ash can be coated with a composition for promoting adhesion. U.S. Pat. No. 5,064,876 to Hamada et al. and U.S. Pat. No. 5,082,738 to Swofford, for example, disclose compositions for promoting adhesion. In some embodiments, the fibers, coarse filler material, and/or the fly ash are surface coated with a composition comprising a silane compound such as aminosilane. U.S. Pat. No. 4,062,999 to Kondo et al. and U.S. Pat. No. 6,602,379 to Li et al. describe suitable aminosilane compounds for coating fibers. In some embodiments, the polyurethane composites can include a combination of coated and uncoated fibers, coarse filler material, and/or the fly ash. In some examples, the coarse filler material can be coated with an aminosilane.
Additional components useful with the polyurethane composite can include foaming agents, blowing agents, surfactants, chain-extenders, crosslinkers, coupling agents, UV stabilizers, fire retardants, antimicrobials, anti-oxidants, and pigments. For example, the fibers, coarse filler material, and/or the fly ash can be coated with a surfactant, bonding agent, pigment, or combinations thereof. Though the use of such components is well known to those of skill in the art, some of these additional additives are further described herein.
Chemical foaming agents include azodicarbonamides (e.g., Celogen manufactured by Lion Copolymer Geismar); and other materials that react at the reaction temperature to form gases such as carbon dioxide. Water is an exemplary foaming agent that reacts with isocyanate to yield carbon dioxide. The presence of water as an added component or in the filler also can result in the formation of polyurea bonds through the reaction of the water and isocyanate. In some embodiments, water may be present in the mixture used to produce the polyurethane composite in an amount of from greater than 0% to 5% by weight or less, based on the weight of the mixture. In some embodiments, water can be present in a range of 0.02% to 4%, 0.05% to 3%, 0.1% to 2%, or 0.2% to 1% by weight, based on the weight of the mixture. In some embodiments, the mixture used to produce the polyurethane composite includes less than 0.5% by weight water.
Surfactants can be used as wetting agents and to assist in mixing and dispersing the materials in a composite. Surfactants can also stabilize and control the size of bubbles formed during the foaming event and the resultant cell structure. Surfactants can be used, for example, in amounts below about 0.5 wt % based on the total weight of the mixture. Examples of surfactants useful with the polyurethanes described herein include anionic, non-ionic and cationic surfactants. For example, silicone surfactants such as Tegostab B-8870, DC-197 and DC-193 (Air Products; Allentown, Pa.) can be used.
Low molecular weight reactants such as chain-extenders and/or crosslinkers can be included in the composite described herein. These reactants help the polyurethane system to distribute and contain the fly ash, coarse filler material, and/or fibers within the composite. Chain-extenders are difunctional molecules, such as diols or diamines, that can polymerize to lengthen the urethane polymer chains. Examples of chain-extenders include ethylene glycol; 1,4-butanediol; ethylene diamine, 4,4′-methylenebis(2-chloroaniline) (MBOCA); diethyltoluene diamine (DETDA); and aromatic diamines such as Unilink 4200 (commercially available from UOP). Crosslinkers are tri- or greater functional molecules that can integrate into a polymer chain through two functionalities and provide one or more further functionalities (i.e., linkage sites) to crosslink to additional polymer chains. Examples of crosslinkers include glycerin, trimethylolpropane, sorbitol, diethanolamine, and triethanolamine. In some composites, a crosslinker or chain-extender may be used to replace at least a portion of the one or more polyol in the composite material. For example, the polyurethane can be formed by the reaction of an isocyanate, a polyol, and a crosslinker.
Coupling agents and other surface treatments such as viscosity reducers, flow control agents, or dispersing agents can be added directly to the filler or fiber, or incorporated prior to, during, and/or after the mixing and reaction of the composite material. Coupling agents can allow higher filler loadings of the particulate filler such as fly ash and/or the coarse filler material and may be used in small quantities. For example, the composite material may comprise about 0.01 wt % to about 0.5 wt % of a coupling agent. Examples of coupling agents useful with the composite materials described herein include Ken-React LICA 38 and KEN-React KR 55 (Kenrich Petrochemicals; Bayonne, N.J.). Examples of dispersing agents useful with the composite materials described herein include JEFFSPERSE X3202, JEFFSPERSE X3202RF, and JEFFSPERSE X3204 (Huntsman Polyurethanes; Geismar, La.).
Ultraviolet light stabilizers, such as UV absorbers, can be added to the composite materials described herein. Examples of UV light stabilizers include hindered amine type stabilizers and opaque pigments like carbon black powder. Fire retardants can be included to increase the flame or fire resistance of the composite material. Antimicrobials can be used to limit the growth of mildew and other organisms on the surface of the composite. Antioxidants, such as phenolic antioxidants, can also be added. Antioxidants provide increased UV protection, as well as thermal oxidation protection.
Pigments or dyes can optionally be added to the composite materials described herein. An example of a pigment is iron oxide, which can be added in amounts ranging from about 2 wt % to about 7 wt %, based on the total weight of the composite material.
Methods of preparing the polyurethane composites are described herein. The polyurethane composites can be formed by the reaction of one or more isocyanate, selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and one or more polyol, in the presence of a coarse filler material, fly ash, and optionally, a fiber material and/or a catalyst. In some embodiments, the polyurethane composite can be produced by mixing the one or more isocyanates, the one or more polyols, the coarse filler material, and the fly ash, in a mixing apparatus such as a high speed mixer or an extruder. In some embodiments, mixing can be conducted in an extruder. The materials can be added in any suitable order. For example, in some embodiments, the mixing stage of the method used to prepare the polyurethane composite can include: (1) mixing the polyol, coarse filler material, and fly ash; (2) mixing the isocyanate with the polyol, coarse filler material, and fly ash; and optionally (3) mixing the catalyst with the isocyanate, the polyol, the coarse filler material, and the fly ash. The optional fiber material can be added at the same time as the coarse filler material or fly ash, or can be added prior to, during, or after stage (2) or (3).
The polyurethane composite mixture can be blended in any suitable manner to obtain a homogeneous or heterogeneous blend of the one or more isocyanate, one or more polyol, fly ash, coarse filler material, optional fiber, and optional catalyst. An ultrasonic device can be used for enhanced mixing and/or wetting of the various components of the composite. The ultrasonic device produces an ultrasound of a certain frequency that can be varied during the mixing and/or extrusion process. The ultrasonic device useful in the preparation of composite materials described herein can be attached to or adjacent to an extruder and/or mixer. For example, the ultrasonic device can be attached to a die or nozzle or to the port of an extruder or mixer. An ultrasonic device may provide de-aeration of undesired gas bubbles and better mixing for the other components, such as blowing agents, surfactants, and catalysts.
The mixture can then be extruded into a mold cavity of a mold, the mold cavity formed by at least an interior mold surface. The mold can be a continuous forming system such as a belt molding system or can include individual batch molds. The belt molding system can include a mold cavity formed at least in part by opposing surfaces of two opposed belts. A molded article can then be formed followed by removal of the article from the mold.
Incorporation of the coarse filler material into the filled polyurethane mixture (that is, the polyol, isocyanate, coarse filler material, and fly ash) can decrease the viscosity of the mixture. In some embodiments, it is desirable that the composite mixture has a viscosity below a particular threshold at the desired loadings so it can be effectively processed. In some embodiments, the coarse filler material can be present in the composite mixture in amounts to produce a workable viscosity of from 25 Pa·s to 250 Pa·s. For example, the coarse filler material in the composite mixture can be in amounts to produce a workable viscosity from 30 Pa·s to 250 Pa·s, 65 Pa·s to 250 Pa·s, or 80 Pa·s to 250 Pa·s. In some embodiments, the working viscosity can be less than 250 Pa·s, less than 225 Pa·s, less than 200 Pa·s, less than 175 Pa·s, less than 150 Pa·s, less than 140 Pa·s, less than 130 Pa·s, less than 120 Pa·s, or less than 110 Pa·s. The polyurethane mixture may be processed at an elevated temperature (e.g., 200-500° F.) to form a melt and to allow the mixture to have a workable viscosity. In some embodiments, the fly ash and/or the coarse filler material are heated before mixing with the polyurethane. The viscosity of the composite mixture can be measured using a Thermo Electron Corporation Haake Viscometer.
In some embodiments, the composite mixture described herein can be foamed. The polyol and the isocyanate can be allowed to produce a foamed composite material after mixing the components according to the methods described herein. The composite materials can be formed while they are actively foaming or after they have foamed. For example, the material can be placed under the pressure of a mold cavity prior to or during the foaming of the composite material.
Incorporation of the coarse filler material in the polyurethane composite can increase the flexural strength of a composite, compared to a composite without the coarse filler material. In some embodiments, the flexural strength of the polyurethane composites can be increased by at least 10%, for example, 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, 50% or greater, 75% or greater, or even 100% or greater, compared to a composite without coarse filler materials.
The flexural strength of the polyurethane composites described herein can be 300 psi or greater. For example, the flexural strength of the polyurethane composites can be 500 psi or greater, 700 psi or greater, 900 psi or greater, 1000 psi or greater, 1100 psi or greater, 1200 psi or greater, 1300 psi or greater, 1400 psi or greater, 1500 psi or greater, or 1600 psi or greater. The flexural strength can be determined by the load required to fracture a rectangular prism loaded in the three point bend test as described in ASTM C1185-08 (2012).
Incorporation of the coarse filler material in the polyurethane composite can increase the packing density of the fillers in the composite, compared to a composite without the coarse filler material. In some embodiments, the packing density of the fillers in the polyurethane composites can be increased by at least 0.5%, for example, 0.7% or greater, 1% or greater, 1.5% or greater, 2% or greater, 3% or greater, 5% or greater, or 8% or greater, compared to the packing density of fillers in a composite without coarse filler materials. The packing density of the fillers in the polyurethane composites described herein can be 1.1 g/ml or greater. For example, the packing density of the polyurethane composites can be 1.2 g/ml or greater, or 1.3 g/ml or greater. The packing density can be determined by packing the composite materials into a graduated cylinder held onto a table vibrated by a Syntron magnetic vibrator for several minutes until the material no longer reduces in volume, then calculating the density. The method is modified based on tapped density obtained using ASTM D7481-09.
The granulometry of the coarse filler material and/or fly ash can be determined by a variety of techniques. For example, analysis of the particle size distribution of the fly ash or coarse filler material can be conducted using a Horiba LA-300 laser interferometer with isopropanol dispersion media. The multimodal distribution can be analyzed into its component parts by mathematical deconvolution using a computer program such as MATLAB® from Mathworks.
The optimization of various properties, such as density and flexural strength, of the composite allows their use in building materials and other structural applications. For example, the polyurethane composites can be formed into shaped articles and used in building materials include siding materials, roofing materials such as roof coatings and roof tiles, architectural moldings, sheets, decking materials, synthetic lumber, sound barrier/insulation, thermal barriers, carpet backing, fencing materials, marine lumber, flexible or rigid foams such as automotive foams (e.g., for dashboard, seats or roofing), component coatings, and other shaped articles. Examples of shaped articles made using composite materials described herein include roof tile shingles, trim boards, building panels, scaffolding, cast molded products, doors, door parts, moldings, sills, stone, masonry, brick products, posts, signs, guard rails, retaining walls, park benches, tables, slats, corner arches, columns, wall boards, ceiling tiles, ceiling boards, soffits, and railroad ties. The polyurethane composites described herein further can be used as reinforcement of composite structural members including building materials such as doors, windows, furniture, and cabinets and for well and concrete repair. The polyurethane composites described herein also can be used to fill gaps, particularly to increase the strength of solid surface articles and/or structural components. The polyurethane composites can be flexible, semi-rigid or rigid foams. In some embodiments, the flexible foam is reversibly deformable (i.e. resilient) and can include open cells. An 8″×1″×1″ piece of a flexible foam can generally wrap around a 1″ diameter mandrel at room temperature without rupture or fracture. Flexible foams also generally have a density of less than 5 lb/ft3 (e.g. 1 to 5 lb/ft3). In some embodiments, the rigid foam is irreversibly deformable and can be highly crosslinked and/or can include closed cells. Rigid foams generally have a density of 5 lb/ft3 or greater.
In some embodiments, the overall density of the polyurethane composites and/or the molded articles described herein can be 2 lb/ft3 or greater. For example, the overall density can be 5 lb/ft3 to 75 lb/ft3, 10 lb/ft3 to 70 lb/ft3, 15 lb/ft3 to 65 lb/ft3, 20 lb/ft3 to 60 lb/ft3, 25 lb/ft3 to 55 lb/ft3, or 10 lb/ft3 to 35 lb/ft3.
EXAMPLESThe following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of the disclosure. Unless indicated otherwise, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric.
Effect of Blast Sand or Geotex Filler Materials on Packing DensityThe packing density of mixtures of fly ash and blast sand of Geotex filler was determined by fly ash and filler material (in amounts disclosed in
Results:
Method:
Polyol compositions used to simulate highly filled polyurethane systems were prepared by mixing a polyol blend containing 30% by weight CARPOL® MX-425 (Mannich base polyether polyol), 19.7% by weight CARPOL® GP-725 (alkylene oxide-capped glycerine), 19.3% by weight CARPOL® GSP-355 (sucrose-based polyether polyol), 19% by weight TEROL® 352 (aromatic polyester polyol), and 10% by weight EDAP-800 (ethylene diamine, propylene oxide and ethylene oxide based polyether polyol) to produce a polyol mixture. Fly ash and blast sand or Geotex filler materials (in the amounts disclosed in
Results:
Methods:
Polyurethane composites were prepared using blast sand, obtained from Keller Materials, TX, USA, or Poraver, obtained from North America Inc, Innisfil, Ontario. The Poraver materials are a family of lightweight expanded glass/clay materials. The composites were prepared by mixing a polyol blend containing 30% by weight CARPOL® MX-425 (Mannich base polyether polyol), 19.7% by weight CARPOL® GP-725 (alkylene oxide-capped glycerine), 19.3% by weight CARPOL® GSP-355 (sucrose-based polyether polyol), 19% by weight TEROL® 352 (aromatic polyester polyol), and 10% by weight EDAP-800 (ethylene diamine, propylene oxide and ethylene oxide based polyether polyol) to produce a polyol mixture. The polyol mixture was then mixed with 1% by weight of an amine catalyst (diethanolamine), and 2% by weight of a silicone surfactant (Tegostab B-8870) in an extruder. Fly ash, glass fiber, and blast sand or Poraver were added and wetted with the liquid solution. Methylene diphenyl diisocyanate (MDI; 104 index; 51.5 g) was then added to the extruder, and simultaneously stirring began. The mixture was extruded into a belt molding system and allowed to cure. The resultant composites included 23 parts by weight polyurethane, 70 parts by weight fly ash, 7 parts by weight glass fiber, and the weight percentage of blast sand or Poraver provided in Tables 1 and 2. The physical properties of the resultant composites, including flexural strength and density were determined.
Results:
Tables 1 and 2 describe the flexural strength and density of highly filled polyurethane composite materials with different levels of addition of blast sand and Poraver materials, respectively. A flexural strength of about 1400 psi was achieved with 20% by weight addition of blast sand at a density of 37.1 pcf, 4% by weight addition of Poraver 0.5-1 mm at a density of 37.2 pcf and 6% by weight addition of Poraver 0.2-0.5 mm at a density of 38 pcf, compared to about 1000 psi at similar density level for the control formulation (
Summary:
In addition to the advantage in processing of the starting mixture of the final composite, the use of coarse filler materials in highly-filled polyurethane composite also improves the mechanical properties such as flexural strength while permitting a reduction in cost of the composite. The addition of the coarse filler material also improves the packing of filler particles in the filler-fiber-polyurethane system and makes the structure denser and stronger. Because the total porosity is reduced, less polyurethane is required to form an optimal structure for satisfactory performance and thus reduces the cost of the composite products without compromising the mechanical properties. The reduced porosity allows for a greater amount of the polyol and MDI mixture available to coat particles and form the struts of the composite.
Effect of Glass Fibers on Blast Sand or Poraver Filled Polyurethane Composite
Methods:
Polyurethane composites were prepared by mixing a polyol blend containing 30% by weight CARPOL® MX-425 (Mannich base polyether polyol), 19.7% by weight CARPOL® GP-725 (alkylene oxide-capped glycerine), 19.3% by weight CARPOL® GSP-355 (sucrose-based polyether polyol), 19% by weight TEROL® 352 (aromatic polyester polyol), and 10% by weight EDAP-800 (ethylene diamine, propylene oxide and ethylene oxide based polyether polyol) to produce a polyol mixture. The polyol mixture was then mixed with 1% by weight of an amine catalyst (diethanolamine), and 2% by weight of a silicone surfactant (Tegostab B-8870) in an extruder. Fly ash, a coarse filler, and glass fibers (in the amounts disclosed in Table 3), were added and wetted with the liquid solution. Methylene diphenyl diisocyanate (MDI; 104 index; 51.5 g) was then added to the extruder, and simultaneously stirring began. The following mixtures were prepared: (1) fly ash only (23 wt % polyurethane and 77 wt % of fillers and glass fiber) as provided in the first column of Table 3; (2) a blend of fly ash and blast sand with a weight ratio of 5:1 (20 wt % polyurethane and 80 wt % of fillers and glass fiber) as provided in the second column of Table 3; and (3) a blend of fly ash and Poraver 0.5-1 mm with a weight ratio of 25:1 (22.4% polyurethane and 77.6% wt % of fillers and glass fiber) as provided in the third column of Table 3.
The mixtures were extruded into a belt molding system and allowed to cure. The physical properties of the composites, including flexural strength and density were determined.
Results:
Table 3 lists the flexural strength and density of highly-filled polyurethane with various levels of glass fibers. It is shown that, the flexural strength of the composite with either blast sand or Poraver 0.5-1 mm increases to above 1500 psi when fiber glass contents increases, while that of the control formulation levels off at about 880 psi (See
As shown in
Conclusion:
The partial volumetric replacement of fly ash by a coarse filler material or a combination of coarse filler materials increased the packing density of the filler particles in highly-filled polyurethane system and reduce the viscosity of the material, leading to improvements in the workability and mechanical performance of the polyurethane composites.
The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, which are intended as illustrations of a few aspects of the claims and any compositions and methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Further, while only certain representative materials and method steps disclosed herein are specifically described, other combinations of the materials and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein; however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated. The term “comprising” and variations thereof as used herein is used synonymously with the term “including” and variations thereof and are open, non-limiting terms. Although the terms “comprising” and “including” have been used herein to describe various embodiments, the terms “consisting essentially of” and “consisting of” can be used in place of “comprising” and “including” to provide for more specific embodiments and are also disclosed. As used in this disclosure and in the appended claims, the singular forms “a”, “an”, “the”, include plural referents unless the context clearly dictates otherwise.
Claims
1. A composite comprising:
- (a) a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols;
- (b) from 20% to 90% by weight, based on the total weight of the composite, of fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns; and
- (c) from 1% to 40% by weight, based on the total weight of the composite, of a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from greater than 250 microns to 10 mm,
- wherein the weight ratio of the fly ash to the coarse filler material is from 9:1 to 200:1.
2. The composite of claim 1, wherein the particle size of the 80% or greater by weight, filler particles is from greater than 500 microns to 1 mm.
3. The composite of claim 1, wherein the particle size of the 80% or greater by weight, filler particles is from 300 microns to 500 microns.
4. (canceled)
5. The composite of claim 1, wherein the coarse filler material includes silica sand, silica fume, cement, slag, metakaolin, talc, mica, wollastonite, limestone, calcium carbonate, perlite, clay, shale, ceramic, glass, seed hull, organic waste, or combinations thereof.
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. The composite of claim 1, further comprising a fiber material, wherein the fiber material is present in an amount of from 1% to 20% by weight, based on the total weight of the composite.
11. (canceled)
12. The composite of claim 9, wherein the fiber material includes a plurality of glass fibers.
13. (canceled)
14. (canceled)
15. The composite of claim 1, wherein the fly ash is present in an amount of from 50% to 80% by weight, based on the total weight of the composite.
16. (canceled)
17. The composite of claim 1, wherein the fly ash has a particle size distribution comprising a first mode having a median particle diameter from 0.3 micron to 1 micron, a second mode having a median particle diameter from 10 microns to 25 microns, and a third mode having a median particle diameter from 40 microns to 80 microns.
18. The composite of claim 17, wherein the weight ratio of the fly ash to the coarse filler material is from 9:1 to 150:1.
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. The composite of claim 1, wherein the composite has a density of from 5 lb/ft3 to 70 lb/ft3.
24. (canceled)
25. (canceled)
26. A building material comprising the composite of claim 1.
27. (canceled)
28. A composite comprising:
- (a) from 15% to 60% by weight, based on the total weight of the composite, of a polyurethane formed by the reaction of (i) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, and (ii) one or more polyols;
- (b) from 20% to 80% by weight, based on the total weight of the composite, of Class C fly ash having a particle size distribution comprising a first mode having a median particle diameter from 0.3 micron to 1 micron, a second mode having a median particle diameter from 10 microns to 25 microns, and a third mode having a median particle diameter from 40 microns to 80 microns;
- (c) from 1% to 40% by weight, based on the total weight of the composite, of a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from 250 microns to 10 mm, and
- (d) from 1% to 20% by weight, based on the total weight of the composite, of a glass fiber material,
- wherein the weight ratio of the fly ash to the coarse filler material is from 9:1 to 200:1.
29. The composite of claim 28, wherein the particle size of the 80% or greater by weight, filler particles is from 300 microns to 1 mm.
30. (canceled)
31. The composite of claim 28, wherein the coarse filler material includes silica sand, silica fume, cement, slag, metakaolin, talc, mica, wollastonite, limestone, calcium carbonate, perlite, clay, shale, ceramic, glass, seed hull, organic waste, or combinations thereof.
32. The composite of claim 28, further comprising a fiber material selected from polyacrylonitrile fibers, polyamide fibers, polyester fibers, glass fibers, mineral wool, rayon, cellulose, wood fiber, saw dust, wood shavings, cotton, lint, polypropylene fibers, polyethylene fibers, polyacrylic fibers, or combinations thereof.
33. (canceled)
34. The composite of claim 28, wherein the weight ratio of the Class C fly ash to the coarse filler material is from 9:1 to 150:1.
35. (canceled)
36. A method of making a polyurethane composite comprising:
- (a) mixing (1) one or more isocyanates selected from the group consisting of diisocyanates, polyisocyanates, and mixtures thereof, (2) one or more polyols, (3) 20% to 90% by weight, based on the total weight of the composite, of fly ash comprising 50% or greater by weight, fly ash particles having a particle size of from 0.2 micron to 100 microns, and (4) 1% to 40% by weight, based on the total weight of the composite, of a coarse filler material comprising 80% or greater by weight, filler particles having a particle size of from 250 microns to 10 mm to form a mixture, wherein the weight ratio of the fly ash to the coarse filler material is from 9:1 to 200:1; and
- (b) allowing the one or more isocyanates and the one or more polyols to react in the presence of the fly ash and the coarse filler material to form the polyurethane composite.
37. The method of claim 36, wherein the mixture further comprises a catalyst.
38. The method of claim 36, wherein the mixture further includes 1% to 20% by weight, based on the total weight of the mixture, of a fiber material.
39. The method of claim 36, wherein the coarse filler material includes silica sand, silica fume, cement, slag, metakaolin, talc, mica, wollastonite, limestone, calcium carbonate, perlite, clay, shale, ceramic, glass, seed hull, organic waste, or combinations thereof.
40. (canceled)
41. (canceled)
Type: Application
Filed: Nov 12, 2015
Publication Date: Sep 21, 2017
Inventors: Amitabha KUMAR (San Antonio, TX), Li AI (San Antonio, TX), Russell HILL (San Antonio, TX)
Application Number: 15/301,083
