Abstract: The present invention provides a polycarbonate having a low particle content, a process for producing high-purity polycarbonate and polycarbonate of maximum purity and molded products made from such polycarbonate.

Abstract: Copolymers of polycarbonates or polyarylates with polyether polymers such as polyethersulfones, polyetherketones, and polyetherimides are prepared by reaction of the polyether polymer-forming reagents, e.g., bisphenol A disodium salt and bis(4-chlorophenyl) sulfone, in the presence of the polycarbonate or polyarylate. The reaction may take place in a dipolar aprotic solvent, or in a water-immiscible aromatic solvent in the presence of a phase transfer catalyst, preferably a hexaalkylguanidinium halide. Hydroxy-terminated polyether oligomers may be produced from the copolymers by saponification of carbonate or ester groups.

Abstract: The invention relates to transparent blends of polymers suitable for use in optical articles; the polymers contain residues of BCC and its derivatives, and have properties particularly suited for use in high density optical data storage media. The polymers further contain residues of other polymers, such as &agr;-methyl polystyrene and polystyrene derivatives; bisphenols, such as bisphenol A; cycloaliphatic polyester resins, such as PCCD and its derivatives or some combination of each.

Abstract: Copolymers of polycarbonates or polyarylates with polyether polymers such as polyethersulfones, polyetherketones, and polyetherimides are prepared by reaction of the polyether polymer-forming reagents, e.g., bisphenol A disodium salt and bis(4-chlorophenyl) sulfone, in the presence of the polycarbonate or polyarylate. The reaction may take place in a dipolar aprotic solvent, or in a water-immiscible aromatic solvent in the presence of a phase transfer catalyst, preferably a hexaalkylguanidinium halide. Hydroxy-terminated polyether oligomers may be produced from the copolymers by saponification of carbonate or ester groups.

Abstract: A thermoplastic resin composition comprising an aromatic polysulfone resin and at least one resin selected from aromatic polyester resins, wherein the amount of alkali metal which exists in the aromatic polysulfone resin as a terminal phenolate is 50 ppm or less, and molded article thereof. This composition is excellent in heat resistance and melt-mold processability.

Abstract: The present invention provides a composition comprising polycarbonate wherein the polycarbonate has a very low Fries content (e.g., above 5 ppm and below 360 ppm). The present invention also provides a polycarbonate having a very low Fries content which is made by the melt process. This polycarbonate has high ductility and high impact strength. The invention also provides a method for making these compositions. Another aspect of the invention is an optical disk comprising polycarbonate having a very low Fries content which is made by the melt process. Such optical disks resist breakage due to bending.

Abstract: A current limiting device comprises at least two electrodes; an electrically conducting composite material between the electrodes; interfaces between the electrodes and electrically conducting composite material; an inhomogeneous distribution of resistance at the interfaces whereby, during a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and at least a partial physical separation at the interfaces; and a structure for exerting compressive pressure on the electrically conducting composite material, wherein the electrically conducting composite material comprises at least one polymer matrix and at least one conductive filler.

Abstract: This invention provides certain polycarbonates and polycarbonate blends useful in optical article applications. In a preferred embodiment, copolymers of, for example, certain ortho substituted bisphenol A-based polycarbonates and bisphenol A, optionally further comprising polycarbonate residues derived from ortho subsitituted spirobiindane compounds and alkylene or cycloalkylene diacid moieties. In a further embodiment, the invention provides copolymers of certain ortho-substituted bisphenol A moieties and ortho-substituted spirobiindane moieties. Also provided are optical articles comprised of the copolymers and blends of the invention. We have found that such copolymers and blends exhibit superior dimensional stability when exposed to water or moisture.

Abstract: A fluorescent article is disclosed in which a U.V. light screening layer comprising a polymer having in its backbone repeating units of a U.V. light absorbing moiety, or a moiety capable of being transformed by Photo-Fries rearrangement into a U.V. light absorbing moiety, is disposed in operative screening relation to a layer containing a fluorescent colorant. The U.V. light screening layer affords surprisingly improved fluorescence protection as compared to prior U.V. light screening layers having only U.V. light absorbing additives.

Abstract: Copolymers of BPA, BPT-1 and BPT-2, can be used as a modifier to enhance the thermal properties of a BPA polymer. A single copolymer modifier can be used in differing amounts to produce a product with desired thermal properties. Thus, polycarbonate can be made by combining a bisphenol A polycarbonate and a BPA/BPT-1/BPT-2 copolymer modifier, and mixing the combined materials to form a blend. By adjusting the relative amounts and the properties of the bisphenol A polycarbonate and BPA/BPT-1/BPT-2 copolymer, the glass transition temperature and the toughness of the blend can be selected. Suitable BPA/BPT-1/BPT-2 copolymers contain BPT-1 and BPT-2 in a ratio, BPT-1/BPT-2, in the range of 70/30 to 10/90, preferably less than or equal to 50/50, for example around 30/70.

Abstract: A poly(carbonate-co-ester) block copolymer is synthesized using synthetic strategies that can be incorporated into conventional melt facilities that are commonly used in the production of polycarbonate polymers. The polycarbonate block of the poly(carbonate-co-ester) copolymer is derived from a polycarbonate reaction mixture comprising an aromatic dihydroxy compound and a carbonic acid diester, such as bisphenol A and diphenyl carbonate, respectively. The second block of the copolymer is derived from a polyester prepolymer, the polyester prepolymer comprising a diol, diacid or diester, and at least one monomer that is selected to advantageously incorporate desired properties into the poly(carbonate-co-ester) copolymer. The polyester prepolymer is introduced to the polycarbonate reaction mixture to form the poly(carbonate-co-ester) copolymer. Properties of the copolymer can be altered by varying numerous conditions of the reaction.

Abstract: Copolymers of BPA and menthane bisphenols such as BPT1 and BPT2 can be used as a compatabilizer to allow the formation of homogeneous blends of BPA with menthane bisphenol polycarbonates such as poly-BPT1 or poly-BPT2 or copolymers thereof. Thus, a compatible polycarbonate blend is made by combining a bisphenol A polycarbonate, a menthane bisphenol polycarbonate and a BPA/menthane bisphenol copolymer compatabilizer, and mixing the combined materials to form a blend. The compatabilizer may contain one or more species of menthane bisphenol. In a specific example, BPT1 and BPT2 are used in the compatabilizer in a ratio, BPT1/BPT2, in the range of 70/30 to 10/90, preferably less than or equal to 1/1, for example around 30/70. By adjusting the relative amounts and the properties of the bisphenol A polycarbonate and the menthane bisphenol polycarbonate, the glass transition temperature and the toughness of the blend can be selected.

Abstract: Aliphatic tricarboxylic acids, as exemplified by 9-carboxy-1,18-octadecanedioic acid, may be prepared by the biotransformation of an olefinic monocarboxylic acid such as oleic acid to the corresponding olefinic dicarboxylic acid, preferably 1,18-octadec-9-enedioic acid, in the presence of a strain of yeast, such as a strain of Candida tropicalis, followed by the carboxylation of the olefinic dicarboxylic acid by reaction with carbon monoxide and water in the presence of a catalyst. The product tricarboxylic acids are useful as branching agents for polycarbonates.

Abstract: The object of the present invention is to provide a flame-retardant resin composition which has a high heat resistance, superior impact resistance and superior flame-retarding properties. The present invention provides a flame-retardant resin composition which is characterized by the fact that said composition contains (A) a polycarbonate type resin, (B) a silicone resin constructed from siloxane units expressed by the formula RSiO1.5 (T units) and siloxane units expressed by the formula R3SiO0.5 (M units), or a silicone resin constructed from T units, M units and siloxane units expressed by the formula SiO2.0 (Q units) (R indicates an unsubstituted or substituted monovalent hydrocarbon group with 1 to 10 carbon atoms), and (C) an anti-drip agent, and the aforementioned composition contains 0.1 to 9 parts by weight of the abovementioned silicone resin (B), and 0.01 to 10 parts by weight of the abovementioned anti-drip agent, per 100 parts by weight of the abovementioned polycarbonate resin (A).

Abstract: A flame resistant thermoplastic molding composition is disclosed. The composition contains a mixture of two aromatic polycarbonates having differing solution viscosities, a vinyl(co)polymer made from at least two ethylenically unsaturated monomers, a graft polymer obtainable by graft polymerization of at least two monomers selected from chloroprene, 1,3-butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth)acrylates with 1 to 18 carbon atoms in the alcohol component, a phosphorous compound, a fluorinated polyolefin and an inorganic compound with an average particle size no greater than 200 nm. The inventive composition is additionally characterized in its improved stress cracking resistance.

Abstract: The present invention provides: a process for producing a high molecular weight thermoplastic resin composition, which can give the high molecular weight thermoplastic resin composition with good reproducibility and stably; and uses of the resultant resin composition. The process for producing a high molecular weight thermoplastic resin composition comprises the step of mixing a thermoplastic resin with pyromellitic dianhydride to carry out a reaction therebetween to convert the thermoplastic resin into a high molecular weight one, and this process is characterized in that the pyromellitic dianhydride has at least one of the following properties in particle form: (1) intrinsically linear or needle-like particle forms; (2) a bulk density of 0.4˜0.9 g/ml; and (3) a rest angle of 50˜70 degrees.

Abstract: A flame-resistant, reinforced thermoplastic molding composition characterized by its improved properties is disclosed. The composition contains A) a mixture of two aromatic polycarbonate resins that differ one from the other in terms of their relative solution viscosities, B) an optional vinyl (co)polymer containing at least one ethylenically unsaturated monomer, C) a graft polymer, D) a phosphorus compound, E) fluorinated polyolefin, and F) inorganic reinforcing material.

Abstract: Copolymers of BPA and menthane bisphenols such as BPT1 and BPT2 can be used as a compatabilizer to allow the formation of homogeneous blends of BPA with menthane bisphenol polycarbonates such as poly-BPT1 or poly-BPT2 or copolymers thereof. Thus, a compatible polycarbonate blend is made by combining a bisphenol A polycarbonate, a menthane bisphenol polycarbonate and a BPA/menthane bisphenol copolymer compatabilizer, and mixing the combined materials to form a blend. The compatabilizer may contain one or more species of menthane bisphenol. In a specific example, BPT1 and BPT2 are used in the compatabilizer in a ratio, BPT1/BPT2, in the range of 70/30 to 10/90, preferably less than or equal to 1/1, for example around 30/70. By adjusting the relative amounts and the properties of the bisphenol A polycarbonate and the menthane bisphenol polycarbonate, the glass transition temperature and the toughness of the blend can be selected.

Abstract: An aromatic-aliphatic copolycarbonate and a process for producing the same which comprises polycondensation of an aromatic dihydroxy compound, such as 1,1-bis(4-hydroxyphenyl)cyclohexane, tricyclo(5.2.1.02,6)decanedimethanol, and a carbonic acid diester in a molten state under heating, wherein the carbonic acid diester has a chlorine content of 20 ppm or lower. The copolycarbonate has improved refractive index, balance of dispersion, and photoelastic constant while retaining high impact resistance, high heat resistance, and excellent hue.

Abstract: Copolymers of polycarbonates or polyarylates with polyether polymers such as polyethersulfones, polyetherketones, and polyetherimides are prepared by reaction of the polyether polymer-forming reagents, e.g., bisphenol A disodium salt and bis(4-chlorophenyl)sulfone, in the presence of the polycarbonate or polyarylate. The reaction may take place in a dipolar aprotic solvent, or in a water-immiscible aromatic solvent in the presence of a phase transfer catalyst, preferably a hexaalkylguanidinium halide. Hydroxy-terminated polyether oligomers may be produced from the copolymers by saponification of carbonate or ester groups.

Abstract: An aromatic-aliphatic copolycarbonate and a process for producing the same which comprises polycondensation of an aromatic dihydroxy compound, such as 1,1-bis(4-hydroxyphenyl)cyclohexane, tricyclo(5.2.1.02,6)decanedimethanol, and a carbonic acid diester in a molten state under heating, wherein the carbonic acid diester has a chlorine content of 20 ppm or lower. The copolycarbonate has improved refractive index, balance of dispersion, and photoelastic constant while retaining high impact resistance, high heat resistance, and excellent hue.

Abstract: The present invention discloses a resin composition reclaimed from compact disk waste having improved mechanical characteristics. The resin composition in accordance with the present invention comprises (a) compact disk waste comprising polycarbonate (PC) as a primary component; and (b) a coupling agent containing two or more reactive functional groups. Optionally, the resin composition of the present invention may further comprise (c) an impact-resistant thermoplastic resin, engineering plastic grade PC or waste thereof, or recycled bottle grade PC.

Abstract: An aromatic-aliphatic copolycarbonate and a process for producing the same which comprises polycondensation of an aromatic dihydroxy compound, such as 1,1-bis(4-hydroxyphenyl)cyclohexane, tricyclo(5.2.1.02,6)decanedimethanol, and a carbonic acid diester in a molten state under heating, wherein the carbonic acid diester has a chlorine content of 20 ppm or lower. The copolycarbonate has improved refractive index, balance of dispersion, and photoelastic constant while retaining high impact resistance, high heat resistance, and excellent hue.

Abstract: A thermoplastic resin composition can be obtained by adding about 0.1 to 20 parts by weight of a diene-series block copolymer (2) to 100 parts by weight of a resin composition containing a polycarbonate-series resin (1) as a basic component of which the proportion of terminal hydroxy groups relative to the whole of the terminals is 1 mole % or above (about 5 to 40 mole %). The polycarbonate-series resin base may further comprise a thermoplastic resin composition (3) such as a rubber-modified styrenic resin. The block copolymer component (2) includes an epoxy-modified block copolymer, etc. When added an organophosphorus compound as a flame retardant (4), or a fluorine-containing resin as a flame-retartant auxiliary (5), a halogen-free flame-retardant thermoplastic resin composition can be obtained. A thermoplastic resin with an improved flowability and impact strength can be obtained by modifying a polymer blend of the polycarbonate-series resin and the styrenic-series resin in quality.

Abstract: The invention provide biodegradable copolymers of the copoly(ester-amide) or copoly(ester-urethane) type, which copolymers consist of building blocks with the general structure (I): [CB-VB] wherein CB and VB of different building blocks may be the same or different, and CB represents a block with a constant length and VB represents a block with a variable length.

Abstract: Polymer alloys comprising polycarbonate having a Fries branching controlled between 300 to 5,000 ppm and also comprising a rubber exhibit superior molding and flow properties.

Abstract: Provided are a flame-retardant polycarbonate resin composition capable of being formed into moldings having good impact resistance, high strength and good thermal stability that are intrinsic to polycarbonate resins and having good antistatic properties and good flame retardancy, and also injection moldings of the composition. The composition comprises 100 parts by weight of a resin or resin mixture of (A) from 50 to 100% by weight of a polycarbonate resin and (B) from 0 to 50% by weight of a styrenic resin, from 1 to 50 parts by weight of (C) a flame retardant, and from 0.1 to 5 parts by weight of (D) an anionic antistatic agent, and has a sodium sulfate content of at most 0.05% by weight. Optionally, the composition may contain (F) a fluoro-olefinic resin, (G) a rubber-like elastomer, and (H) an inorganic filler.

Abstract: To obtain an injection-molded article of a resin composition blended with a thermoplastic resin and a liquid-crystal polymer, which is excellent in mechanical strengths, etc., by forming the liquid-crystal polymer into fibers during molding. The molded article, wherein the liquid-crystal polymer (B) capable of forming an anisotropic molten phase is present in the form of fiber having an average aspect ratio of 6 or higher in a matrix of the thermoplastic resin (A) not forming an anisotropic molten phase, is produced by injection-molding a thermoplastic resin composition obtained by blending 100 parts by weight of a resin component consisting of 99 to 50 parts by weight of the thermoplastic resin (A) not forming an anisotropic molten phase and 1 to 50 parts by weight of the liquid-crystal polymer (B) capable of forming an anisotropic molten phase with 0.01 to 1.0 part by weight of at least one compound (C) selected from the group consisting of phosphoric acid, phosphorous acid and metal salts thereof.

Abstract: Process for preparing a thermosetting coating composition comprising;(a) mixing(i) a cleavable carbonyl polymer having an activated carbonyl group adjacent to oxygen or nitrogen, in the backbone, and having a molecular weight greater than 5,000(ii) a multifunctional compound having a molecular weight less than 5,000 having a functional group capable of reacting with the cleavable carbonyl polymer to cleave the polymer at the carbonyl group and bond with the cleaved polymer, the compound having a crosslinking group;(b) reacting the mixture in an extruder, at 50 to 350.degree. C. for 15 to 600 seconds, to cleave the polymer, and react the cleaved polymer with the functional group on the multifunctional compound(c) quenching the reaction mixture cooling prior to equilibrium reaction, to produce a functionalized cleaved polymer having crosslinking groups derived from the multifunctional compound and capable of crosslinking by heat reaction outside the extruder.

Abstract: A method for producing an aromatic polycarbonate which comprises subjecting to a transesterification polymerization reaction at least one polymerizable material selected from a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, and a molten prepolymer obtained from the monomer mixture, wherein the transesterification reaction is performed in one or more polymerizers which is or are connected through a pipeline system toward an outlet for a final aromatic polycarbonate product, wherein the pipeline system comprises one or more pipes through which a molten aromatic polycarbonate having a number average molecular weight increased by the transesterification polymerization reaction is passed while contacting an inner wall of the pipe or pipes, and wherein a molten aromatic polycarbonate having a number average molecular weight of less than 2,500 is passed through the pipe or pipes at a velocity of 0.05 m/sec.

Abstract: Disclosed is a method for producing a homogeneous polycarbonate composition, which comprises feeding a first polycarbonate in a molten state to a first inlet of an extruder, while feeding a mixture of an second polycarbonate and at least one thermal stabilizer to a second inlet of the extruder, wherein the second inlet is disposed downstream of the first inlet, and extruding the first polycarbonate and the mixture through the extruder. By the method of the present invention, additives can be uniformly dispersed in a molten polycarbonate without dissolving the additives in a solvent, and a polycarbonate composition of the polycarbonate and the additive, which has various excellent properties, such as excellent thermal stability, can be produced efficiently.

Abstract: Molding materials containA) from 5 to 97.9% by weight of at least one polycarbonate having a weight average molecular weight (M.sub.w) of from 10,000 to 64,000 g/mol,B) from 1 to 93.9% by weight of at least one graft copolymer,C) from 1 to 93.9% by weight of at least one copolymerc.sub.1) at least one vinylaromatic compound of the general formula I ##STR1## where R is hydrogen or C.sub.1 -C.sub.8 -alkyl, R.sup.1 is C.sub.1 -C.sub.8 -alkyl and n is an integer from 0 to 3, or of a C.sub.1 -C.sub.8 -alkyl acrylate, a C.sub.1 -C.sub.8 -alkyl C.sub.1 -C.sub.8 -alkylacrylate or a mixture thereof and c.sub.2) acrylonitrile, C.sub.1 -C.sub.8 -alkylacrylonitrile or a mixture thereof,D) from 0.01 to 10% by weight of at least one polyhydroxyether of at least one aliphatic or aromatic diol with epihalohydrin,E) from 1 to 25% by weight of at least one halogen-free phosphorus compound andF) from 0 to 50% by weight of additives.

Abstract: The weight average molecular weight of a polycarbonate resin is predictably reduced by reaction with a multifunctional aliphatic compound at a temperature of 250 C. to 350 C.

Abstract: A highly useful photographic film base containing a miscible blend of is polyester containing at least 30 weight percent cyclohexylene dimethanol, CHDM/EG-PE, and a polycarbonate containing bisphenols, BP-PC, in specified proportions. Photographic elements prepared with this film base have a lesser tendency to take core-set and post process curl than do elements prepared with polyester containing cyclohexylene dimethanol, CHDM/EG-PE, film base.

Abstract: Redistribution of polycarbonate compositions is effected in the presence of a tetraorganophosphonium hydroxide as catalyst and a catalyst decomposing amount of a polyhydroxyaliphatic compound such as glyceryl monostearate, pentaerythritol or ethylene glycol. Catalyst decomposition after redistribution improves the stability of the redistributed polycarbonate composition.

Abstract: Branched polycarbonates having properties suitable for blow molding are prepared by equilibrating a linear or branched aromatic polycarbonate with certain tetraphenols, especially 2,2,5,5-tetrakis (4-hydroxyphenyl)hexane and ?1,1-bis(p-hydroxyphenyl)ethyl!-phenyl ether.

Abstract: The mold release performance of pentaerythritol esters is enhanced in polycarbonate resin moldings by partial replacement with an ester of dipentaerythritol.

Abstract: Polymer mixtures which comprise at least one thermoplastic and at least one oxidized polyarylene sulfide show particularly good tribological behaviour. The thermoplastics of the mixture are, for example, polyacetal, polyester, liquid-crystalline polymer, polyaryl ether ketone, polysulfone, polyether sulfone, polyphenylene sulfide or polyether imide. The oxidized polyarylene sulfide is preferably polyphenylene sulfone. The polymer mixtures are used for producing gear wheels, gear racks, bearings, chains, pulleys, rollers, wheels or gasket materials.

Abstract: The invention relates to a process for increasing the molecular weight of polycondensates, which comprises heating a polycondensate in the temperature range below the melting point and above the glass transition temperature in the solid phase of the polymer with additionof at least one sterically hindered hydroxyphenylalkylphosphonic ester or monoester.

Abstract: Improved branched carbonate polymer blend compositions are prepared comprising a branched carbonate polymer component and a different linear carbonate polymer component. The branched carbonate polymers according to the invention are especially suitable for use in extrusion, blow molding, thermoforming and foaming processes and provide improved parts or articles.

Abstract: For optical applications, transparent amorphous thermo-plastics, such as polyaryl ether ketones, are of considerable interest. However, polyaryl ether ketones have inadequate UV stability and weathering resistance while amorphous polyaryl esters do not have these negative properties. The properties can be improved by means of polymer alloys, giving weathering-resistant materials from homogeneously mixed polymers which comprise at least one amorphous polyaryl ether ketone and at least one amorphous polyaryl ester.

Abstract: A compound of the formula: ##STR1## is blended with a polycarbonate resin to obtain an ultra-violet light degradation resistant article.

Abstract: An improved method for the preparation of tris(4-hydroxyphenyl) compounds is provided. In particular, an improved method for preparing 1, 1,1-tris(4'-hydroxyphenyl)ethane is provided which comprises heating a mixture comprising phenol and 4-hydroxy acetophenone in the presence of effective amounts of an ion exchange catalyst and a mercaptan as a copromoter such that the resulting 1,1,1-tris(4'-hydroxyphenyl)ethane is substantially free of various reaction impurities.

Abstract: Compatibilized blends of poly(phenylene ether) resins and polyester resins are provided from nucleophile containing poly(phenylene ether) resins and polyester resins and compatibilizer compounds to afford articles having good impact, ductility and tensile properties. The compositions may further comprise impact modifiers, metal salts, reinforcing agents, flame retardants and flow promoters. Articles made from the compositions are useful for automotive components. Polymers chain extended with multifunctional orthoesters are claimed.

Abstract: A method for preparing a processable polyisothianaphthene polymer includes steps of dissolving an isothianaphthene monomer in a solvent and introducing therein an initiator to initiate a polymerization reaction to produce a precursor of poly(dihydroisothianaphthene), dissolving thoroughly the precursor of poly(dihydroisothianaphthene) in the solvent in an appropriate ratio to obtain a poly(dihydroisothianaphthene) solution, proceeding a dehydrogenation reaction for the poly(dihydroisothianaphthene) solution by introducing a dehydrogenation agent to obtain a polyisothianaphthene microgel solution, and terminating the dehydrogenation reaction by introducing an inhibitor. This invention offers a simple, feasible, and economical way to prepare a large-area film with uniform film thickness, excellent stability, and good electrochromic, conducting, and mechanical properties.

Abstract: The invention pertains to a non-linear optically active (NLO) side chain polycarbonate and to NLO active waveguides containing said polycarbonate. Waveguides containing this NLO polycarbonate have a low loss of signal. Polycarbonates based on bischloroformates of hexafluorobisphenol A, hexafluorotetrabromobisphenol A and bisphenol S or deuterated bisphenol A or sulphonylbiphenol are especially preferred within the framework of the invention: they were found to give an exceptionally low loss of signal. The invention further pertains to cross-linkable and already cross-linked polycarbonates. Especially preferred polycarbonates according to the invention are those where the diol comprises a rigid donor group. These polycarbonates have a high Tg, which renders them thermally stable.

Abstract: Polyestercarbonates, particularly those containing aliphatic dicarboxylic acid-derived structural units, are redistributed by heating in the presence of a carbonate redistribution catalyst, and, optionally, a diaryl carbonate. The redistribution products have weight average molecular weights different from, and typically lower than, the initial molecular weight.

Abstract: Polycarbonate compositions are redistributed by melt equilibration using diethyldimethylammonium hydroxide as the redistribution catalyst. This catalyst affords an odorless polycarbonate product having a very low residual amine level.

Abstract: A process is disclosed whereby a polymeric resin (containing ester and/or carbonate bonds) is readily converted into a resin having a modified molecular structure. Accordingly, a cyclic carbonate (a monomer or oligomer) is transesterified with the polymer resin in the melt, preferably upon extrusion, optionally in the presence of a catalyst. Significantly, the cyclic carbonate which may include any of a variety of functional groups may, by the inventive process, be inserted into the structure of the polymer, effecting a modification to the structure and the properties of the resin. Among the disclosed beneficial modifications thus imparted to the resin are improved thermal stability, altered rheology and optical properties.

Abstract: An optical disk substrate formed substantially of an aromatic polycarbonate from an aromatic dihydroxy component containing at least 20 mol % of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,wherein:(A) the aromatic polycarbonate has a specific viscosity of 0.2 to 0.5,(B) the aromatic polycarbonate shows a water absorption percentage of 0.2 % by weight or less,(C) the aromatic polycarbonate has an oligomer content of 10 % or less, and(D) the number of undissolved particles having a diameter of 0.5 .mu.m or greater is 25,000 pieces or less per g of the polycarbonate resin, and the number of undissolved particles having a diameter of 1 .mu.m or greater is 500 pieces or less per g of the polycarbonate resin, and an optical disk from the above substrate.