Polycarbonate compositions, articles formed therefrom, and methods for making same

Abstract

The polycarbonate composition includes a specific amount of bisphenol A homopolycarbonate, a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer, and a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. The composition can provide a desirable combination of properties, including good flammability, chemical resistance, and aesthetic properties.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to and the benefit of European Patent Application No. 22197822.4, filed September 26, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to polycarbonate compositions, articles formed therefrom, and methods for their manufacture. The compositions described herein can exhibit advantageous properties, such as improved aesthetics, flame retardancy, and improved chemical resistance. [Background technology]

[0003] Polycarbonates are useful in a wide variety of applications at least in part because of their good balance of properties such as moldability, heat resistance, and impact properties, among others. Despite extensive research into these materials over the years, there remains a need in the art for improved polycarbonate compositions that meet increasingly stringent industry standards.

[0004] For example, polycarbonate-polysiloxane copolymers can have good mechanical properties and low-temperature impact resistance. However, blending such polycarbonate-polysiloxanes with polycarbonate homopolymers can reduce the aesthetics of molded parts. Aesthetic defects can include excessive haze, limited color space capability, pearlescence, or other molding-related surface defects such as streaks and flow lines. Previous attempts to improve aesthetics can compromise other desirable properties, such as low-temperature impact resistance, flame retardancy, and chemical resistance. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there remains a need in the art for polycarbonate compositions that can have a balance of aesthetics, flame retardancy, and chemical resistance. [Means for solving the problem]

[0006] The polycarbonate composition comprises 20 to 85 weight percent bisphenol A homopolycarbonate, 10 to 55 weight percent of a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer, and 10 to 25 weight percent of a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 weight percent to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. and a second polycarbonate-siloxane copolymer, wherein when the composition has a total siloxane content of 2 to 7.5%, the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of less than 2, and when the composition has a total siloxane content of greater than 7.5% to 15%, the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of 2 to 5.

[0007] Another aspect is a method of making a polycarbonate composition, comprising melt mixing the components of the composition and, optionally, extruding the composition.

[0008] Another aspect is an article comprising the polycarbonate composition.

[0009] These and other features are exemplified by the following detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present inventors have discovered that polycarbonate compositions comprising a specific amount of bisphenol A homopolycarbonate, a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer, and a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer, can provide a desirable combination of properties. For example, compositions according to the present disclosure have been found to exhibit improved aesthetic properties, flame retardancy, and chemical resistance.

[0011] Thus, one aspect of the present disclosure is a polycarbonate composition. The polycarbonate composition includes a bisphenol A homopolycarbonate. The bisphenol A homopolycarbonate has repeating structural carbonate units of formula (1). [ka] (1) Bisphenol A polycarbonate homopolymers can be produced from bisphenol A (2,2-bis(4-hydroxyphenyl)propane, or BPA) by known methods, such as interfacial polymerization and melt polymerization, as described, for example, in WO 2013 / 175448 and WO 2014 / 072923. End groups, such as monocyclic phenols, e.g., phenol, p-cyanophenol, and C 1-22An end-capping agent can be included in the polymerization to provide alkyl-substituted phenols such as p-cumylphenol, resorcinol monobenzoate, and p-tert-butylphenol, monoethers of diphenols such as p-methoxyphenol, monoesters of diphenols such as resorcinol monobenzoate, functionalized chlorides of aliphatic monocarboxylic acids such as acryloyl chloride and methacryloyl chloride, and monochloroformates such as phenyl chloroformate, alkyl-substituted phenyl chloroformate, p-cumylphenyl chloroformate, and toluene chloroformate. Specific examples include phenol and para-cumylphenol. Combinations of different end-capping agents can be used. Branched polycarbonate blocks can be prepared by adding branching agents during polymerization, such as trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxyphenylethane, isatin-bis-phenol, tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl)α,α-dimethylbenzyl)phenol), 4-chloroformylphthalic anhydride, trimesic acid, and benzophenone tetracarboxylic acid. Branching agents can be added at levels of 0.05 to 4.0 weight percent (wt%), for example, 0.05 to 2.0 wt%. Combinations including linear and branched polycarbonates can be used.

[0012] The bisphenol A polycarbonate homopolymer may be a linear bisphenol A polycarbonate homopolymer, optionally end-capped with phenol or para-cumylphenol, and having a weight average molecular weight of 10,000 to 100,000 grams / mole (g / mol), or 10,000 to 75,000 g / mol, or 18,000 to 40,000 g / mol, or 20,000 to 40,000 g / mol, or 28,000 to 38,000 g / mol, as measured by gel permeation chromatography (GPC) using a cross-linked styrene-divinylbenzene column and calibrated against a bisphenol A polycarbonate reference. GPC samples are prepared at a concentration of 1 milligram / milliliter (mg / mL) and eluted at a flow rate of 1.5 mL / min.

[0013] In one embodiment, two or more bisphenol A polycarbonate homopolymers may be present. For example, the bisphenol A polycarbonate homopolymer may include a first bisphenol A polycarbonate homopolymer having a first weight-average molecular weight and a second bisphenol A polycarbonate homopolymer having a second weight-average molecular weight, where the first and second weight-average molecular weights are not the same. If present, the weight ratio of the first bisphenol A polycarbonate homopolymer to the second bisphenol A polycarbonate homopolymer may be 10:1 to 1:10, or 5:1 to 1:5, or 3:1 to 1:3, or 2:1 to 1:2.

[0014] The bisphenol A homopolycarbonate may be present in the composition in an amount from 20 to 85 weight percent, based on the total weight of the composition. Within this range, the bisphenol A homopolycarbonate may be present in an amount from 25 to 75 weight percent, or from 30 to 70 weight percent, or from 30 to 65 weight percent, or from 35 to 65 weight percent, or from 40 to 65 weight percent, or from 45 to 65 weight percent, or from 40 to 60 weight percent, or from 40 to 55 weight percent, or from 30 to 55 weight percent, or from 30 to 50 weight percent, or from 40 to 50 weight percent, each based on the total weight of the composition.

[0015] In addition to the bisphenol A homopolycarbonate, the polycarbonate composition further includes a first polycarbonate-siloxane copolymer and a second polycarbonate-siloxane copolymer. The polycarbonate-siloxane copolymer is also known as polycarbonate-siloxane. Both the first and second polycarbonate-siloxane copolymers contain carbonate repeating units and siloxane units. The carbonate units can be derived from a dihydroxy aromatic compound, such as a bisphenol of formula (2) or a diphenol of formula (3). [ka] (2) [ka] (3) (In formula (2), R a and R b are each independently 1-12 Alkyl, C 1-12 Alkenyl, C 3-8 Cycloalkyl, or C 1-12 alkoxy, p and q are each independently 0 to 4, and X a represents a single bond, -O-, -S-, -S(O)-, -S(O)2-, -C(O)-, a group of the formula -C(R c )(R d )-(wherein, R cand R d are each independently hydrogen or C 1-10 C of alkyl 1-11 Alkylidene, or a compound of the formula -C(=R e )-(wherein, R e is a divalent C 1-10 In formula (3), each R h are independently a halogen atom, e.g., bromine, C 1-10 Alkyl, halogen-substituted C 1-10 Alkyl, C 6-10 Aryl or halogen-substituted C 6-10 C such as aryl 1-10 is a hydrocarbyl group, and n is an integer of 0 to 4.

[0016] In one embodiment of formulas (2) and (3), R a and R b are each independently 1-3 Alkyl or C 1-3 alkoxy, p and q are each independently 0 or 1, and X a represents a single bond, -O-, -S(O)-, -S(O)2-, -C(O)-, and the formula -C(R c )(R d )-(wherein, R c and R d are each independently hydrogen or C 1-10 C of alkyl 1-11 alkylidene, and each R h are independently bromine, C 1-3 Alkyl, halogen-substituted C 1-3 It is alkyl, and n is 0 to 1.

[0017] In one embodiment of formulas (2) and (3), R a and R b are each independently 1-3 alkyl, p and q are each independently 0 or 1, and X a represents a single bond, -O-, -S(O)-, -S(O)2-, -C(O)-, and the formula -C(R c )(R d )-(wherein, R cand R d are each independently hydrogen or C 1-10 C of alkyl 1-11 alkylidene, and each R h are independently bromine, C 1-3 Alkyl, halogen-substituted C 1-3 It is alkyl, and n is 0 to 1.

[0018] In one embodiment of formula (2), p and q are each independently 0; a represents a single bond, -O-, -S(O)-, -S(O)2-, -C(O)-, and the formula -C(R c )(R d )-(wherein, R c and R d are each independently hydrogen or C 1-10 C of alkyl 1-11 It is an alkylidene.

[0019] In one embodiment of formula (2), p and q are each independently 0; a is the formula -C(R c )(R d )-(wherein, R c and R d are each independently hydrogen or C 1-10 C of alkyl 1-11 It is an alkylidene.

[0020] In one embodiment of formula (2), p and q are each independently 0; a is the formula -C(R c )(R d )-(wherein, R c and R d are each independently 1-10 alkyl, preferably methyl) 1-11 It is an alkylidene.

[0021] Examples of bisphenol compounds (2) include BPA, 4,4'-dihydroxybiphenyl, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane, and bis(4-hydroxyphenyl) Phenylmethane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutene, 1,1-bis(4-hydroxyphenyl)cyclododecane, trans-2,3-bis(4-hydroxyphenyl)-2-butene, 2,2-bis(4-hydroxyphenyl)adamantane, α,α'-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-n-propyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-hydroxyphenyl)propane, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 2,2-bis(3-allyl-4-hydroxyphenyl)propane phenyl)propane, 2,2-bis(3-methoxy-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene, 1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene, 4,4'-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone, 1,6-bis(4-hydroxyphenyl)-1,Examples of suitable bisphenols include 6-hexanedione, ethylene glycol bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorene, 2,7-dihydroxypyrene, 6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane (spirobiindane bisphenol), 3,3-bis(4-hydroxyphenyl)phthalimide, 2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene, 2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine, 3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and 2,7-dihydroxycarbazole. Combinations containing different bisphenol compounds can also be used.

[0022] Examples of the diphenol compound (3) include resorcinol, substituted resorcinol compounds such as 5-methylresorcinol, 5-ethylresorcinol, 5-propylresorcinol, 5-butylresorcinol, 5-t-butylresorcinol, 5-phenylresorcinol, 5-cumylresorcinol, 2,4,5,6-tetrafluororesorcinol, and 2,4,5,6-tetrabromoresorcinol; catechol; hydroquinone; and substituted hydroquinones. Hydroquinones such as 2-methylhydroquinone, 2-ethylhydroquinone, 2-propylhydroquinone, 2-butylhydroquinone, 2-t-butylhydroquinone, 2-phenylhydroquinone, 2-cumylhydroquinone, 2,3,5,6-tetramethylhydroquinone, 2,3,5,6-tetra-t-butylhydroquinone, 2,3,5,6-tetrafluorohydroquinone, 2,3,5,6-tetrabromohydroquinone, etc. Combinations comprising different diphenol compounds can be used.

[0023] In one embodiment, the carbonate units may be bisphenol carbonate units derived from a bisphenol of formula (2): A preferred bisphenol is bisphenol A (BPA).

[0024] The siloxane units (also called polysiloxane blocks) are optionally of formula (4): [ka] (4) wherein each R is independently C 1-13 For example, R is C 1-13 Alkyl, C 1-13 Alkoxy, C 2-13 Alkenyl, C 2-13 Alkenyloxy, C 3-6 Cycloalkyl, C 3-6 Cycloalkoxy, C 6-14 Aryl, C 6-10 Aryloxy, C 7-13 Aryl alkylene, C 7-13 Arylalkyleneoxy, C 7-13 Alkylarylene, or C 7-13 The R groups may be alkylaryleneoxy. The foregoing groups may be fully or partially halogenated with fluorine, chlorine, bromine, or iodine, or a combination thereof. In one embodiment in which a transparent poly(carbonate-siloxane) is desired, R is not substituted with halogen. Combinations of the foregoing R groups may be used in the same copolymer.

[0025] In one embodiment, R is C 1-3 Alkyl, C 1-3 Alkoxy, C 3-6 Cycloalkyl, C 3-6 Cycloalkoxy, C 6-14 Aryl, C 6-10 aryloxy, C7 arylalkylene, C7 arylalkyleneoxy, C7 alkylarylene, or C7 alkylaryleneoxy. In one embodiment, R is methyl, trifluoromethyl, or phenyl, preferably methyl.

[0026] The value of E in formula (4) can vary widely depending on considerations such as the type and relative amounts of each component in the polycarbonate composition and the desired properties of the composition. Generally, E has an average value of 2 to 1,000, or 2 to 500, or 2 to 200, or 2 to 125, or 5 to 80, or 10 to 70. In one embodiment, E has an average value of 10 to 80 or 10 to 40; in yet another embodiment, E has an average value of 40 to 80 or 40 to 70; and in yet another embodiment, E has an average value of 10 to 100, or 20 to 60, or 30 to 50.

[0027] In one embodiment, the siloxane unit is of formula (5): [ka] (5) wherein E is as defined above in the context of formula (4), each R may be the same or different and is as defined above in the context of formula (4), and Ar may be the same or different and is a substituted or unsubstituted C 6-30 The Ar group in formula (5) is C 6-30 It can be derived from a dihydroxyarylene compound, for example, a dihydroxy compound of formula (3). Exemplary dihydroxyarylene compounds are 1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulfide), and 1,1-bis(4-hydroxy-t-butylphenyl)propane, or a combination thereof.

[0028] Specific examples of the siloxane unit of formula (5) include siloxane units of formulas (5a) and (5b). [ka] (5a) [ka] (5b)

[0029] In one embodiment, the siloxane unit is of formula (6): [ka] (6) where R and E are as described above in the context of formula (4), and each R 5 are independently divalent C 1-30 is an organic group, and the polymerized polysiloxane units are the reacted residues of their corresponding dihydroxy compounds.) In one embodiment, the polydiorganosiloxane blocks are of formula (7): [ka] (7) (wherein R and E are as defined above in the context of formula (4)). R in formula (7) 6 is a divalent C 2-8 Each M in formula (7) may be the same or different and may be a halogen, cyano, nitro, C 1-8 Alkylthio, C 1-8 Alkyl, C 1-8 Alkoxy, C 2-8 Alkenyl, C 2-8 Alkenyloxy, C 3-8 Cycloalkyl, C 3-8 Cycloalkoxy, C 6-10 Aryl, C 6-10 Aryloxy, C 7-12 Aralkyl, C 7-12 Arylalkylenoxy, C 7-12 Alkylarylene, or C 7-12It can be alkylaryloxy, where each n is independently 0, 1, 2, 3, or 4.

[0030] In one embodiment, M is bromo or chloro, alkyl, such as methyl, ethyl, or propyl, alkoxy, such as methoxy, ethoxy, or propoxy, or aryl, such as phenyl, chlorophenyl, or tolyl; R 6 is dimethylene, trimethylene, or tetramethylene, and R is C 1-8 In one embodiment, R is methyl, or a combination of methyl and trifluoropropyl, or a combination of methyl and phenyl. In one embodiment, R is methyl, M is methoxy, n is 1, and R 6 is a divalent C 1-3 Certain polydiorganosiloxane blocks have the formula [ka] (7a) [ka] (7b) [ka] (7c) or a combination thereof, wherein E has an average value of 10-100, preferably 20-60, more preferably 30-50, or 40-50.

[0031] The blocks of formula (7) can be derived from the corresponding dihydroxypolydiorganosiloxanes by known methods. Polycarbonate-siloxanes can be prepared by introducing phosgene into a mixture of bisphenols and endblocked polydimethylsiloxane (PDMS) under interfacial reaction conditions. Other known methods can also be used.

[0032] In one embodiment, the poly(carbonate-siloxane) comprises carbonate units derived from bisphenol A and repeating siloxane units (5a), (5b), (7a), (7b), (7c), or combinations thereof (preferably those of formula 7a), where E has an average value of 10 to 100, preferably 20 to 80, or 30 to 70, more preferably 30 to 50 or 40 to 50.

[0033] The present inventors have unexpectedly discovered that polycarbonate compositions can exhibit a desirable combination of properties, including good chemical resistance, flame retardancy, and aesthetic properties, when certain combinations of polycarbonate-siloxane copolymers are used in the compositions.

[0034] The first polycarbonate-siloxane copolymer can have a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer. Within this range, the first polycarbonate-siloxane copolymer can have a siloxane content of 5 to less than 10 weight percent, or 5 to 9 weight percent, or 4 to 9 weight percent, or 4 to 8 weight percent, or 5 to 8 weight percent, or 5 to 7 weight percent. As used herein, the "siloxane content" of a poly(carbonate-siloxane) refers to the content of siloxane units relative to the total weight of the polycarbonate-siloxane copolymer.

[0035] The second polycarbonate-siloxane copolymer can have a siloxane content of 30 to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. Within this range, the second polycarbonate-siloxane copolymer can have a siloxane content of 35 to 65 weight percent, or 35 to 60 weight percent, or 30 to 50 weight percent, or 35 to 55 weight percent, or 35 to 45 weight percent.

[0036] The first polycarbonate-siloxane copolymer can have a weight average molecular weight of 10,000 to 50,000 g / mol, or 15,000 to 40,000 g / mol, or 20,000 to 30,000 g / mol, or 20,000 to 25,000 g / mol, as measured by gel permeation chromatography using a cross-linked styrene-divinylbenzene column at a sample concentration of 1 milligram per milliliter and calibrated with bisphenol A polycarbonate standards.

[0037] The second polycarbonate-siloxane copolymer can have a weight average molecular weight of 21,000 to 50,000 g / mol. Within this range, the weight average molecular weight can be 25,000 to 45,000 g / mol, or 30,000 to 45,000 g / mol, or 32,000 to 43,000 g / mol, or 34,000 to 41,000 g / mol, or 35,000 to 40,000 g / mol. The weight average molecular weight can be measured by gel permeation chromatography using a cross-linked styrene-divinylbenzene column at a sample concentration of 1 milligram per milliliter and calibrated with bisphenol A polycarbonate standards.

[0038] In one embodiment, the composition comprises less than 5 weight percent, or 1 weight percent or less, or 0.1 weight percent or less of polycarbonate-siloxanes having a siloxane content of greater than 10 weight percent but less than 30 weight percent, e.g., 12 to 28 weight percent. Preferably, polycarbonate-siloxanes having a siloxane content of greater than 10 weight percent but less than 30 weight percent, e.g., 12 to 28 weight percent, are excluded from the composition.

[0039] The first and second polycarbonate-siloxane copolymers can each be present in the composition in an amount providing a total siloxane content of 2 to 15 weight percent, or 2 to 12 weight percent, or 2 to 10 weight percent, or 2 to 7.5 weight percent, or 7.5 to 15 weight percent, based on the total weight of the polycarbonate composition. In one embodiment, the composition can have a total siloxane content of 2 to 7.5 weight percent, and the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer can be present in a weight ratio of less than 2 (i.e., less than 2:1), such as less than 1.75, or less than 1.5, or 0.75:1 to 1.5:1, or 0.9:1 to 1.2:1. In one embodiment, the composition can have a total siloxane content of greater than 7.5 weight percent to 15 weight percent, and the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer can be present in a weight ratio of 1.5 to 5 or 2 to 5 (i.e., 2:1 to 5:1), such as 1.5:1 to 5:1, or 2:1 to 4:1, or 2:1 to 3:1.

[0040] The first polycarbonate-siloxane copolymer may be present in the composition in an amount of 10 to 55 weight percent, based on the total weight of the composition. Within this range, the first polycarbonate-siloxane copolymer may be present in an amount of, for example, 10 to 50 weight percent, or 15 to 50 weight percent, or 15 to 45 weight percent, or 20 to 45 weight percent, or 20 to 40 weight percent, or 15 to 40 weight percent, or 25 to 35 weight percent, each based on the total weight of the composition.

[0041] The second polycarbonate-siloxane copolymer may be present in the composition in an amount of 10 to 25 weight percent, based on the total weight of the composition. Within this range, the second polycarbonate may be present in an amount of, for example, greater than 10 to 25 weight percent, or 15 to 25 weight percent, or greater than 15 to 25 weight percent, or 16 to 25 weight percent, or 17 to 25 weight percent, or 18 to 25 weight percent, or 15 to 20 weight percent, or greater than 15 to 20 weight percent, or 17 to 20 weight percent, each based on the total weight of the composition.

[0042] In one embodiment, one or more of the bisphenol A homopolycarbonate, the first polycarbonate-siloxane copolymer, and the second polycarbonate-siloxane copolymer can be derived from post-consumer recycled or post-industrial recycled materials. In one embodiment, one or more of the bisphenol A homopolycarbonate, the first polycarbonate-siloxane copolymer, and the second polycarbonate-siloxane copolymer can be produced from at least one monomer derived from a bio-based or plastic waste feedstock.

[0043] The polycarbonate composition can optionally further comprise an additive composition containing one or more additives typically incorporated into polymer compositions of this type, provided that the one or more additives are selected so as not to significantly adversely affect the desired properties of the polycarbonate composition, particularly impact, chemical, and flame resistance. Additives can include fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, ultraviolet (UV) stabilizers, plasticizers, lubricants, mold release agents, antistatic agents, colorants (e.g., titanium dioxide, carbon black, and organic dyes), surface effect additives, radiation stabilizers, flame retardants, and anti-drip agents. Combinations of additives, such as a combination of heat stabilizers, mold release agents, and UV stabilizers, can also be used. Additives are generally used in amounts generally known to be effective. For example, the total amount of additives (other than any impact modifiers, fillers, or reinforcing agents) can be 0.01 to 5 weight percent based on the total weight of the polycarbonate composition. In one embodiment, the polycarbonate composition comprises up to 5 weight percent of a processing aid, heat stabilizer, antioxidant, ultraviolet absorber, colorant, or combination thereof, based on the weight of the composition.

[0044] In one embodiment, the composition can optionally further comprise a flame retardant. Useful flame retardants can include organic compounds containing phosphorus, bromine, or chlorine. Non-brominated and non-chlorinated phosphorus-containing flame retardants can be preferred for certain applications due to regulatory reasons, such as organic phosphates and organic compounds containing phosphorus-nitrogen bonds.

[0045] Flame-retardant aromatic phosphates include triphenyl phosphate, tricresyl phosphate, isopropylated triphenyl phosphate, phenyl bis(dodecyl) phosphate, phenyl bis(neopentyl) phosphate, phenyl bis(3,5,5′-trimethylhexyl) phosphate, ethyl diphenyl phosphate, 2-ethylhexyl di(p-tolyl) phosphate, bis(2-ethylhexyl) p-tolyl phosphate, tritolyl phosphate, bis(2-ethylhexyl)phenyl phosphate, tri(nonylphenyl) phosphate, bis(dodecyl) p-tolyl phosphate, dibutylphenyl phosphate, 2-chloroethyl diphenyl phosphate, p-tolyl bis(2,5,5′-trimethylhexyl) phosphate, and 2-ethylhexyl diphenyl phosphate. Also useful are di- or polyfunctional aromatic phosphorus-containing compounds, such as resorcinol tetraphenyl diphosphate (RDP), bis(diphenyl) phosphate of hydroquinone, and bis(diphenyl) phosphate of bisphenol A, respectively, and their oligomeric and polymeric counterparts.

[0046] Flame retardant compounds containing phosphorus-nitrogen bonds include phosphazenes, phosphonitrilic chlorides, phosphoric acid ester amides, phosphoric acid amides, phosphonic acid amides, phosphinic acid amides, and tris(aziridinyl)phosphine oxide. These flame retardant additives are commercially available.

[0047] Halogenated materials can also be used as flame retardants, for example, bisphenols, of which the following are representative: 2,2-bis-(3,5-dichlorophenyl)-propane; bis-(2-chlorophenyl)-methane; bis(2,6-dibromophenyl)-methane; 1,1-bis-(4-iodophenyl)-ethane; 1,2-bis-(2,6-dichlorophenyl)-ethane; 1,1-bis-(2-chloro-4-iodophenyl)-ethane. ) ethane; 1,1-bis-(2-chloro-4-methylphenyl)-ethane; 1,1-bis-(3,5-dichlorophenyl)-ethane; 2,2-bis-(3-phenyl-4-bromophenyl)-ethane; 2,6-bis-(4,6-dichloronaphthyl)-propane; and 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2-bis-(3-bromo-4-hydroxyphenyl)-propane. Other halogenated materials include 1,3-dichlorobenzene, 1,4-dibromobenzene, 1,3-dichloro-4-hydroxybenzene, and biphenyls such as 2,2'-dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene, 2,4'-dibromobiphenyl, and 2,4'-dichlorobiphenyl, and decabromodiphenyl oxide, as well as oligomeric and polymeric halogenated aromatic compounds such as the copolycarbonate and carbonate precursors of bisphenol A and tetrabromobisphenol A, such as phosgene. Metal synergists, such as antimony oxide, can also be used with the flame retardants.

[0048] Alternatively, the thermoplastic composition can be essentially free of chlorine and bromine, which is defined as having a bromine or chlorine content of 100 parts per million (ppm) or less, 75 ppm or less, or 50 ppm or less, based on the total weight of the composition.

[0049] Inorganic flame retardants, such as potassium perfluorobutane sulfonate (Rimar salt), potassium perfluorooctane sulfonate, tetraethylammonium perfluorohexane sulfonate, and potassium diphenyl sulfonate. 1-16Salts of alkylsulfonates; such as Na2CO3, K2CO3, MgCO3, CaCO3, and BaCO3, or fluoroanion complexes such as Li3AlF6, BaSiF6, KBF4, K3AlF6, KAlF4, K2SiF6, or Na3AlF6 can also be used.

[0050] When present, the flame retardant may be included in the composition in an amount of 0.01 to 10 weight percent. Within this range, the flame retardant may be present in an amount of 0.1 to 10 weight percent, or 1 to 10 weight percent, or 1 to 8 weight percent, or 2 to 6 weight percent, or 3 to 5 weight percent, each based on the total weight of the composition. In one embodiment, when the flame retardant comprises an inorganic flame retardant, the flame retardant may be present in an amount of 0.05 to 1 weight percent.

[0051] The heat stabilizer additive can include organic phosphites (e.g., triphenyl phosphite, tris-(2,6-dimethylphenyl) phosphite, tris-(mixed mono- and di-nonylphenyl) phosphites, etc.), phosphonates (e.g., dimethylbenzene phosphonate, etc.), phosphates (e.g., trimethyl phosphate, etc.), or combinations thereof. The heat stabilizer can be tris(2,4-di-t-butylphenyl) phosphate, available as IRGAPHOS 168. The heat stabilizer is generally used in an amount of 0.01 to 5 weight percent, based on the total weight of the polymer in the composition.

[0052] Light stabilizers or ultraviolet (UV) absorbing additives, also known as UV stabilizers, can also be used. Light stabilizer additives include benzotriazoles such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, and 2-hydroxy-4-n-octoxybenzophenone, or combinations thereof.

[0053] UV absorbing additives include hydroxybenzophenones, hydroxybenzotriazoles, hydroxybenzotriazines, cyanoacrylates, oxanilides, benzoxazinones, aryl salicylates, monoesters of diphenols such as resorcinol monobenzoate, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB 5411), 2-hydroxy-4-n-octyloxybenzophenone (CYASORB 531), 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol (CYASORB 1164), 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) (CYASORB UV-3638),Poly[(6-morpholino-s-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]], 2-hydroxy-4-octyloxybenzophenone (UVINUL™ 3008), 6-tert-butyl-2-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenyl (UVINUL™ 3026), 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazole-2 -yl)-phenol (UVINUL™ 3027), 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UVINUL™ 3028), 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (UVINUL™ 3029), 1,3-bis[(2'cyano-3',3'-diphenylacryloyl)oxy]-2,2-bis-{[(2'-cyano-3',3'-diphenylacryloyl)oxy]methyl}-propane (UVINUL™ 3030 ), 2-(2H-benzotriazol-2-yl)-4-methylphenol (UVINUL3033), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UVINUL3034), ethyl-2-cyano-3,3-diphenylacrylate (UVINUL3035), (2-ethylhexyl)-2-cyano-3,3-diphenylacrylate (UVINUL3039), N,N'-bisformyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexyl Samethylenediamine (UVINUL4050H), bis-(2,2,6,6-tetramethyl-4-piperidyl)-sebacate (UVINUL4077H), bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-sebacate + methyl-(1,2,2,6,6-pentamethyl-4-piperidyl)-sebacate (UVINUL4092H), 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane (UVINUL 3030);Examples of suitable UV absorbers include 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one); 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane; TINUVIN 234; nano-sized inorganic materials such as titanium dioxide, cerium oxide, and zinc oxide, all with particle sizes of 100 nanometers or less; and combinations thereof. UV absorbers can be used in amounts of 0.01 to 1 part by weight per 100 parts by weight of polycarbonate and impact modifier. UV absorbers that may be particularly useful with the polycarbonate compositions disclosed herein include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (e.g., CYASORB™ 5411, commercially available from Cytec Industries, Inc., Woodland Park, New Jersey) and 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) (e.g., CYASORB UV-3638, commercially available from Cytec Industries, Inc., Woodland Park, New Jersey), or combinations thereof. The UV stabilizer may be present in an amount of 0.01 to 1 wt. %, preferably 0.1 to 0.5 wt. %, and more preferably 0.15 to 0.4 wt. %, based on the total weight of the polycarbonate composition.

[0054] Plasticizers, lubricants, or mold release agents may also be used. For example, there is considerable overlap between these types of materials, and they include phthalate esters such as dioctyl-4,5-epoxy-hexahydrophthalate; tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- or polyfunctional aromatic phosphates such as resorcinol tetraphenyl diphosphate (RDP), bis(diphenyl)phosphate of hydroquinone, and bis(diphenyl)phosphate of bisphenol A; poly-α-olefins; epoxidized soybean oil; silicones, including silicone oils; esters, e.g., fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate, stearyl stearate, pentaerythritol tetrastearate, and the like; polyethylene glycol polymers, polypropylene glycol polymers, poly(ethylene glycol-co-propylene glycol) copolymers, or combinations thereof, e.g., methyl stearate and polyethylene-polypropylene glycol copolymers, in suitable solvents; and waxes, such as beeswax, montan wax, and paraffin wax.

[0055] Anti-drip agents, such as fibril-forming or non-fibril-forming fluoropolymers such as polytetrafluoroethylene (PTFE), can also be used in the composition. The anti-drip agent can be encapsulated by a rigid copolymer, such as styrene-acrylonitrile copolymer (SAN). PTFE encapsulated in SAN is known as TSAN. TSAN contains 50% by weight of PTFE and 50% by weight of SAN, based on the total weight of the encapsulated fluoropolymer. SAN can contain, for example, 75% by weight of styrene and 25% by weight of acrylonitrile, based on the total weight of the copolymer. The anti-drip agent can be used in an amount of 0.1 to 5 weight percent, or 0.1 to 2 weight percent, based on the total weight of the composition.

[0056] In one embodiment, the polycarbonate may include a colorant composition. Suitable colorants include, but are not limited to, those known by their Color Index numbers as Solvent Green 3, Solvent Green 28, Solvent Red 52, Solvent Red 111, Solvent Red 135, Solvent Red 169, Solvent Red 179, Solvent Red 207, Disperse Red 22, Vat Red 41, Solvent Orange 60, Solvent Orange 63, Solvent Violet 13, Solvent Violet 14, Solvent Violet 50, aminoketone black, solvent black 7, nigrosine dyes, Disperse Blue 73, Solvent Blue 97, Solvent Blue 101, Solvent Blue 104, Solvent Blue 138, Disperse Yellow 160, Solvent Yellow 84, Solvent Yellow 93, Solvent Yellow 98, Solvent Yellow 163, Solvent Yellow 160:1, and mixtures comprising at least one of the foregoing colorants. Preferred colorants include Solvent Red 135, Solvent Yellow 163, Solvent Green 3, and mixtures comprising at least one of the foregoing colorants.

[0057] The colorants can be used in amounts and combinations sufficient to darken and opaque the molded article, more specifically to provide the lightness values ​​described below. The specific amount of colorant used can depend, among other factors, on its solubility and extinction coefficient in the polycarbonate composition, and whether it is used in combination with one or more additional colorants. Suitable amounts and combinations can be readily determined by those skilled in the art guided by this disclosure. Typical colorant amounts can be, for example, 0.1 to 1 weight percent, based on the total weight of the composition, e.g., 0.5 to 1 weight percent, based on the total weight of the composition.

[0058] In one embodiment, the colorant composition, when present, can provide a polycarbonate composition with a black color. For example, a dye combination that provides a black color can include a green dye and a red dye. In one embodiment where two dyes are used to provide a black color, the dyes can be used in a weight ratio of 1:99 to 99:1.

[0059] In one embodiment, the composition preferably comprises C 1-16 It can include an additive composition comprising 0.05 to 1 weight percent of an inorganic flame retardant comprising a sulfonate, more preferably potassium perfluorobutanesulfonate, potassium perfluorooctanesulfonate, tetraethylammonium perfluorohexanesulfonate, and potassium diphenylsulfonate, or a combination thereof, and optionally 0.01 to 1 weight percent of an antidrip additive.

[0060] The polycarbonate composition can optionally exclude other components not specifically described herein. For example, the polycarbonate composition can exclude thermoplastic polymers other than bisphenol A homopolycarbonate and the first and second polycarbonate-siloxane copolymers. For example, the composition can minimize or exclude polyesters (e.g., polyesters can be present in an amount of 1 weight percent or less, and preferably, polyesters are excluded from the composition). The composition can optionally exclude polycarbonates other than bisphenol A homopolycarbonate and polycarbonate-siloxane copolymers, such as polyester-carbonates or bisphenol A copolycarbonates other than the polycarbonate-siloxane copolymers. The polycarbonate composition can optionally exclude impact modifiers, such as silicone-based impact modifiers other than poly(carbonate-siloxane) copolymers, methyl methacrylate-butadiene-styrene copolymers, acrylonitrile-butadiene, styrene copolymers, etc., or combinations thereof. The composition can exclude halogenated flame retardants, such as brominated polycarbonates (e.g., polycarbonates containing brominated carbonates include units derived from 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol (TBBPA) and carbonate units derived from at least one dihydroxy aromatic compound that is not TBBPA), brominated epoxies, etc., or combinations thereof. The composition can optionally exclude inorganic flame retardants. The composition can optionally exclude phosphorus-containing flame retardants.

[0061] The compositions can advantageously exhibit one or more desirable properties. For example, it has been discovered that improved chemical resistance can be unexpectedly achieved by combining a bisphenol A homopolycarbonate with a first polycarbonate-siloxane and a second polycarbonate-siloxane, each having a specific siloxane content. These compositions can have balanced properties including two or more of chemical resistance, flame retardancy, and improved color. Without wishing to be bound by theory, it is believed that the unexpected combination of chemical resistance, flame retardancy, and color is achieved by carefully selecting and balancing the first and second polycarbonate-siloxane copolymers used in the compositions, including selecting the weight percent of siloxane units in the polycarbonate-siloxane.

[0062] The composition can have good chemical resistance. In an exemplary embodiment, the polycarbonate composition can have a tensile strain at break after 72 hours of exposure to a sunscreen at 1% strain using an ISO tensile bar at a temperature of 23° C. that is at least 50% of the tensile strain at break of an unexposed reference tested at the same temperature.

[0063] The polycarbonate composition may also have good flame retardant properties. In one embodiment, the UL94 standard for measuring flame retardancy utilizes ratings of V0, V1, V2, or HB, with a V0 rating being better than V1 or V2 and required for many applications at practical part thicknesses. Using this standard, the polycarbonate composition is molded into a molded article having a predetermined thickness. The thinner the article, the more difficult it is to achieve a V0 or V1 rating. In one embodiment, molded samples of the polycarbonate composition may achieve a UL-94 V0 or V1 rating at a thickness of 1.5 millimeters or less, and preferably a V0 or V1 UL-94 rating at a thickness of 1.2 millimeters or less.

[0064] The polycarbonate composition can also exhibit good color, for example, the polycarbonate composition can have an L* value of 10 or less, or 8 or less, or 7 or less, or 6 or less, when measured by the CIE Lab method using a 10 degree observer, D65 illuminant, specular component excluded, measured in reflection mode, and using a sample having a thickness of 3.2 millimeters.

[0065] The polycarbonate composition may further have a good melt viscosity that aids in processing. The polycarbonate composition may have a melt volume rate (MVR, cubic centimeters per 10 minutes (cm)) of 4 to 20, or 7 to 15, or 4 or more, or 5 or more, measured according to ISO 1133 at 300°C under a load of 2.16 kg for 300 seconds. 3 / 10 min)).

[0066] The polycarbonate composition may have a heat distortion temperature (HDT) of 110° C. or greater when measured on a 4 mm thick sample plaque at 1.82 MPa according to ASTM D648.

[0067] In one embodiment, the polycarbonate composition can advantageously exhibit the above-mentioned UL-94 ratings and tensile elongation retention, and optionally can further exhibit one or more of the above-mentioned heat distortion temperatures and melt volume flow rates.

[0068] In one embodiment, the polycarbonate composition can have an L* value of 10 or less, a tensile strain at break of at least 50% of the tensile strain at break of an unexposed reference sample after exposure to a sunscreen, and a UL-94 flame rating of V0 or V1 at a thickness of 1.5 millimeters or less, preferably a UL-94 flame rating of V0 or V1 at a thickness of 1.2 millimeters or less.

[0069] A polycarbonate composition according to the present disclosure can include 20 to 85 weight percent bisphenol A homopolycarbonate, 10 to 55 weight percent of a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer, and 10 to 25 weight percent of a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. The composition can have a total siloxane content of 2 to 7.5%, and the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer can be present in a weight ratio of less than 2. The composition can have a total siloxane content of greater than 7.5 to 15%, and the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer can be present in a weight ratio of 2 to 5. The bisphenol A homopolycarbonate can have a weight average molecular weight of 18,000 to 40,000 grams / mole, or 20,000 to 40,000 grams / mole, or 28,000 to 38,000 grams / mole, as determined by gel permeation chromatography against a linear bisphenol A polycarbonate standard. The first polycarbonate-siloxane copolymer can have a siloxane content of 4 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer. The first polycarbonate-siloxane copolymer can be present in an amount of 15 to 45 weight percent, based on the total weight of the composition. The second polycarbonate-siloxane copolymer can have a siloxane content of 35 to 65 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. The second polycarbonate-siloxane copolymer can be present in the composition in an amount of greater than 15 to 25 weight percent, or 17 to 25 weight percent, based on the total weight of the composition.The composition can include less than 5 weight percent, or less than 1 weight percent, or preferably excludes polycarbonate-siloxane copolymers having a siloxane content of more than 10 weight percent to less than 30 weight percent. The first and second polycarbonate-siloxane copolymers can each include bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units. The second polycarbonate-siloxane copolymer can have a weight average molecular weight of 21,000 to 50,000 g / mol, or 25,000 to 45,000 g / mol, or 30,000 to 45,000 g / mol, or 32,000 to 43,000 g / mol, or 35,000 to 40,000 g / mol, as determined by gel permeation chromatography using a cross-linked styrene-divinylbenzene column at a sample concentration of 1 milligram per milliliter and calibrated with bisphenol A polycarbonate standards. The polycarbonate composition can further comprise 0.1 to 10 weight percent of an additive composition, based on the total weight of the polycarbonate composition. Molded samples of the composition may exhibit one or more of the following: an L* value of 10 or less, or a tensile strain at break of at least 50% of the tensile strain at break of an unexposed reference sample after exposure to a sunscreen or insect repellent, or a UL-94 flammability rating of V0 or V1 at a thickness of 1.5 millimeters or less, preferably a UL-94 flammability rating of V0 or V1 at a thickness of 1.2 millimeters or less.

[0070] In one embodiment, the polycarbonate composition can include 50 to 60 weight percent bisphenol A homopolycarbonate, 25 to 35 weight percent first polycarbonate-siloxane copolymer, and 15 to 20 weight percent second polycarbonate-siloxane copolymer. In one embodiment, the bisphenol A homopolycarbonate can have a weight average molecular weight of 28,000 to 38,000 grams / mole, as determined by gel permeation chromatography against linear bisphenol A polycarbonate standards. The first polycarbonate-siloxane copolymer can have a siloxane content of 4 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer. The second polycarbonate-siloxane copolymer can have a siloxane content of 35 to 65 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer. The composition can include less than 1 weight percent of a polycarbonate-siloxane copolymer having a siloxane content of greater than 10 weight percent and less than 30 weight percent. The first and second polycarbonate-siloxane copolymers can each include bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units.

[0071] Polycarbonate compositions can be produced by various methods known in the art. For example, powdered polycarbonate homopolymer, poly(carbonate-siloxane), and other optional components, optionally along with optional fillers, are first blended in a high-speed mixer or by hand mixing. The blend is then fed to the throat of a twin-screw extruder via a hopper. Alternatively, at least one of the components can be incorporated into the composition by feeding it directly into the extruder downstream via the throat and / or side stuffer, or by compounding it into a masterbatch containing the desired polymer and feeding it to the extruder. The extruder is generally operated at a temperature higher than that required to cause the composition to flow. The extrudate can be immediately quenched in a water bath and pelletized. The pellets thus prepared can be 1 / 4 inch or less in length, as desired. Such pellets can be used for subsequent molding, shaping, or forming.

[0072] Shaped, formed, cast, or molded articles comprising the polycarbonate compositions are also provided. The polycarbonate compositions can be formed into useful shaped articles by various methods, such as injection molding, extrusion, rotational molding, blow molding, and thermoforming. The articles can be molded articles, thermoformed articles, extruded films, extruded sheets, honeycomb structures, one or more layers of multilayer articles, substrates for coated articles, and substrates for metallized articles. Exemplary articles include computer and business machine housings, such as monitor housings, handheld electronic device housings, such as mobile phone housings, electrical connectors, and components such as lighting fixtures, decorative items, home appliances, roofs, greenhouses, sunrooms, swimming pool enclosures, electronic device casings, and signs. Furthermore, the polycarbonate compositions can be used in applications such as automotive panels and trim. Examples of suitable articles include, but are not limited to, panels, quarter panels, rocker panels, trim, fenders, doors, deck lids, trunk lids, hoods, bonnets, roofs, bumpers, fascias, grilles, mirror housings, pillar appliques, cladding, body side moldings, wheel covers, hubcaps, door handles, spoilers, window frames, headlamp bezels, headlamps, tail lamps, tail lamp housings, tail lamp bezels, license plate enclosures, roof racks, and running boards for aircraft, automobiles, trucks, military vehicles (automobiles, automobiles, etc.). exterior and interior components for motor vehicles (including cars, aircraft, and water vehicles), scooters, and motorcycles; enclosures, housings, panels, and parts for outdoor vehicles and devices; enclosures for electrical and communication devices; outdoor furniture; aircraft components; boat and marine equipment including trim, enclosures, and housings; outboard motor housings; depth finder housings; personal watercraft; jet skis; swimming pools; spas; hot tubs; steps; step coverings; building and construction applications such as glass, roofing, window, floor, and decorative window fixtures or treatments;Treated glass coverings for exhibits such as photographs, paintings, posters, etc.; wall panels, and doors; countertops; protected graphics; outdoor and indoor signage; automated teller machine (ATM) enclosures, housings, panels, and parts; computers; desktop computers; portable computers; laptop computers; handheld computer housings; monitors; printers; keyboards; fax machines; copiers; telephones; telephone bezels; mobile telephones; radio transmitters; radio receivers; enclosures, housings, panels, and parts for tools, including lawn and garden tractors, mowers, and lawn and garden tools; window and door trim; sporting goods and toys; snowmobile enclosures, housings, panels, and parts; recreational vehicle panels and components; play equipment; shoelaces; articles made from plastic-wood combinations exemplified by: articles; golf course markers; utility pit covers; lighting fixtures; lamp fittings; network interface device housings; transformer housings; air conditioner housings; cladding or seating for public transportation; cladding or seating for trains, subways, or buses; meter housings; antenna housings; cladding for satellite dishes; coated helmets and personal protective equipment; coated synthetic or natural fabrics; coated painted articles; coated dyed articles; coated phosphor articles; coated foam articles; medical device housings; battery housings, including for electric vehicles, electric bikes, and household and industrial electronics; electric vehicle charging equipment components, including wall box housings, connectors, etc.; wireless charging device components; electronic device protective covers; kitchen appliance components; and similar uses.

[0073] The compositions of the present disclosure can be particularly useful in consumer electronics applications. For example, the articles can be components of consumer electronic devices such as game consoles, game controllers, portable game devices, mobile phones, televisions, personal computers, tablet computers, laptop computers, personal digital assistants, portable media players, digital cameras, portable music players, electrical appliances, power tools, robots, toys, greeting cards, home entertainment systems, loudspeakers, or sound bars. In one embodiment, the articles can be electronic housings for adapters, mobile phones, smartphones, GPS devices, laptop computers, tablet computers, electronic readers, copiers, or solar devices.

[0074] In one embodiment, the article can be a laser-welded article. For example, components or articles such as those described above can be assembled into an article by laser welding. For example, a method for welding a first article comprising the above-described composition to a second thermoplastic article can include physically contacting at least a portion of a surface of the first article with at least a portion of a surface of the second thermoplastic article and applying laser radiation to the first article, wherein the radiation passes through the first article and is absorbed by the second article, generating sufficient heat to weld the first article to the second article. The second thermoplastic article can include a wide variety of thermoplastic polymer compositions that have been made laser-absorbent by means known to those skilled in the art, including, but not limited to, the use of additives and / or colorants such as carbon black. Exemplary polymer compositions may include, but are not limited to, olefin-based polymers including polyethylene and its copolymers and terpolymers, polybutylene and its copolymers and terpolymers, polypropylene and its copolymers and terpolymers; α-olefin polymers including linear or substantially linear interpolymers of ethylene with at least one α-olefin and atactic poly(α-olefin); rubbery block copolymers; polyamides; polyimides; polyesters such as poly(arylates), poly(ethylene terephthalate) and poly(butylene terephthalate); vinyl-based polymers such as polyvinyl chloride, polyvinyl esters such as polyvinyl acetate; acrylic homopolymers, copolymers and terpolymers; epoxies; polycarbonates, polyester-polycarbonates; polystyrene; poly(arylene ethers including poly(phenylene ethers); polyurethanes; phenoxy resins; polysulfones; polyethers; acetal resins; polyoxyethylene; and combinations thereof. More particularly, the polymer is selected from the group consisting of polyethylene, ethylene copolymers, polypropylene, propylene copolymers, polyesters, polycarbonates, polyester-polycarbonates, polyamides, poly(arylene ethers), and combinations thereof.In certain embodiments, the second article comprises an olefin-based polymer, polyamide, polyimide, polystyrene, polyarylene ether, polyurethane, phenoxy resin, polysulfone, polyether, acetal resin, polyester, vinyl-based polymer, acrylic, epoxy, polycarbonate, polyester-polycarbonate, styrene-acrylonitrile copolymer, or a combination thereof. More specifically, the second article can comprise a polycarbonate homopolymer or copolymer, a polyester homopolymer or copolymer, such as poly(carbonate-ester), and a combination thereof. Laser-welded articles are also disclosed, comprising the thermoplastic composition of the present disclosure in a first component laser-welded to a second component comprising the second thermoplastic composition as described above. [Example]

[0075] The present disclosure is further illustrated by the following non-limiting examples.

[0076] The materials used in the following examples are shown in Table 1.

[0077] [Table 1]

[0078] The components of the compositions were blended and extruded. Molded parts for physical testing were prepared by injection molding. Test methods are described in Table 2 below and in the following paragraphs.

[0079] [Table 2]

[0080] Flammability testing was performed according to the procedures in Underwriter's Laboratory Bulletin 94, entitled "Tests for Flammability of Plastic Materials for Parts in Devices and Appliances" (ISBN 0-7629-0082-2), 5th Edition, dated October 29, 1996, incorporating revisions up to and including December 12, 2003. Several ratings can be applied based on burn rate, time to extinguishment, ability to resist dripping, and whether or not the droplets are burning. According to this procedure, materials can be classified as UL94 HB, V0, VI, V2, 5VA, or 5VB. Specimens were aged for more than two days at 23°C and 50% RH or 168 hours at 70°C before testing. Specifically, for the UL 94 20 mm vertical flame test, a set of five flame rods was tested. For each rod, the rod was exposed to a flame and then removed, and the time required for the rod to self-extinguish (first afterflame time, t1) was recorded. The flame was then reapplied and removed, and the time required for the rod to self-extinguish (second afterflame time, t2) and the time for light to glow after burning (afterglow time, t3) were recorded. To achieve a V-0 rating, the afterflame times t1 and t2 of each individual specimen must be 10 seconds or less, the total afterflame time for all five specimens (t1 + t2 for all five specimens) must be 50 seconds or less, the second afterflame time + afterglow time (t2 + t3) of an individual specimen must be 30 seconds or less, the specimen must not have burned or glowed up to the holding clamp, and the cotton indicator must not have ignited due to burning particles or droplets. To achieve a V-1 rating, the afterflame times t1 and t2 of each individual specimen must be 30 seconds or less, the total afterflame time of all five specimens (t1 + t2 for all five specimens) must be 250 seconds or less, the second afterflame time + afterglow time (t2 + t3) of each individual specimen must be 60 seconds or less, the specimen must not be burning or glowing up to the holding clamp, and the cotton indicator must not be ignited by burning particles or droplets.To achieve a V-2 rating, the afterflame times t1 and t2 of each individual specimen must be 30 seconds or less, the total afterflame time of all five specimens (t1 + t2 for all five specimens) must be 250 seconds or less, the second afterflame time + afterglow time (t2 + t3) of each individual specimen must be 60 seconds or less, and the specimen must not be burning or glowing up to the holding clamp, except that the cotton indicator may be ignited by burning particles or droplets.

[0081] Environmental stress cracking resistance (ESCR) describes the accelerated failure of polymeric materials as a result of the combined effects of environment, temperature, and stress. Failure depends primarily on the material properties, chemicals, exposure conditions, and the magnitude of stress. ISO tensile bars were clamped in a semicircular fixture and subjected to a constant strain of 1.0%. The bars were then exposed to the chemicals at 23°C for a specified time. After cleaning, tensile properties were measured at 50 mm / min at room temperature with standard ASTM tensile bars according to ASTM D638.

[0082] <Examples 1 to 12> Table 3 shows the compositions and composition properties of Examples 1-12. As can be seen in Table 3, increasing the content of PC-Si having a siloxane content in the range of 30-60% can decrease the observed MVR of the final composition. Comparing the compositions of Examples 1, 2, 5, and 8 further reveals that increasing the content of PC-Si having a siloxane content in the range of 30-60% can also adversely affect the color of the resulting composition. The inventors unexpectedly discovered that adding a second PC-Si having a siloxane content of less than 10% can improve color. Exposing ASTM tensile bars to chemicals under strain for a period of time, followed by standard tensile testing, showed that adding a PC-Si with a higher Si content can further improve the chemical resistance of the composition. Thus, compositions with a desirable balance of color, MVR, and chemical resistance are provided.

[0083] [Table 3]

[0084] Thus, the present inventors have discovered that blends of specific polycarbonate-siloxane copolymers can provide fine tuning of the properties of the resulting composition, particularly with respect to colorfastness and chemical resistance. As a further advantageous feature, the desired flow (i.e., MVR) can be maintained. Thus, significant improvements are provided by the compositions of the present disclosure.

[0085] The present disclosure further encompasses the following aspects.

[0086] Aspect 1: A polycarbonate composition comprising: 20 to 85 weight percent bisphenol A homopolycarbonate; 10 to 55 weight percent of a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer; and 10 to 25 weight percent of a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 weight percent to 70 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer. and a second polycarbonate-siloxane copolymer, wherein the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of less than 2 when the composition has a total siloxane content of 2 to 7.5%, and wherein the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of 2 to 5 when the composition has a total siloxane content of greater than 7.5% to 15%.

[0087] Aspect 2: The polycarbonate composition of Aspect 1, wherein the bisphenol A homopolycarbonate has a weight average molecular weight of 18,000 to 40,000 grams / mole, or 20,000 to 40,000 grams / mole, or 28,000 to 38,000 grams / mole, as determined by gel permeation chromatography against linear bisphenol A polycarbonate standards.

[0088] Aspect 3: The polycarbonate composition of Aspect 1 or 2, wherein the first polycarbonate-siloxane copolymer has a siloxane content of from 4 to less than 10 weight percent, or from 5 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer, and wherein the first polycarbonate-siloxane copolymer is present in an amount of from 15 to 45 weight percent, based on the total weight of the composition.

[0089] Aspect 4: The polycarbonate composition of any one of Aspects 1-3, wherein the second polycarbonate-siloxane copolymer has a siloxane content of 35 to 65 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer.

[0090] Embodiment 5: The polycarbonate composition of any one of embodiments 1-4, wherein the second polycarbonate-siloxane copolymer is present in the composition in an amount from greater than 15 weight percent to 25 weight percent, or from 17 to 25 weight percent, based on the total weight of the composition.

[0091] Embodiment 6: The polycarbonate composition of any one of embodiments 1-5, wherein the first and second polycarbonate-siloxane copolymers each comprise bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units.

[0092] Aspect 7: The polycarbonate composition of any one of Aspects 1-6, wherein the second polycarbonate-siloxane copolymer has a weight average molecular weight of 21,000 to 50,000 g / mol, or 25,000 to 45,000 g / mol, or 30,000 to 45,000 g / mol, or 32,000 to 43,000 g / mol, or 35,000 to 40,000 g / mol, as determined by gel permeation chromatography using a cross-linked styrene-divinylbenzene column at a sample concentration of 1 milligram per milliliter and calibrated with bisphenol A polycarbonate standards.

[0093] Aspect 8: The polycarbonate composition further comprises 0.1 to 10 weight percent of an additive composition, based on the total weight of the polycarbonate composition; preferably, the additive composition comprises a drip-proofing agent, a flame retardant, a colorant composition, or a combination thereof; more preferably, the additive composition comprises a polycarbonate composition selected from the group consisting of C 1-16 Aspect 8. The polycarbonate composition of any one of aspects 1 through 7, comprising 0.05 to 1 weight percent of an inorganic flame retardant comprising a sulfonate, more preferably potassium perfluorobutanesulfonate (Rimar's salt), potassium perfluorooctanesulfonate, tetraethylammonium perfluorohexanesulfonate, and potassium diphenylsulfonate, or a combination thereof, and optionally, 0.01 to 1 weight percent of an anti-drip additive.

[0094] Embodiment 9: The polycarbonate composition of any one of embodiments 1-8, comprising 50 to 60 weight percent bisphenol A homopolycarbonate, 25 to 35 weight percent of the first polycarbonate-siloxane copolymer, and 15 to 20 weight percent of the second polycarbonate-siloxane copolymer.

[0095] Aspect 10: A method for producing a bisphenol A homopolycarbonate, comprising the steps of: (a) preparing a bisphenol A homopolycarbonate having a weight average molecular weight of 28,000 to 38,000 grams / mole as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards; (b) preparing a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer; and (c) preparing a second polycarbonate-siloxane copolymer having a siloxane content of 4 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer. 10. The polycarbonate composition of embodiment 9, wherein the first and second polycarbonate-siloxane copolymers have a siloxane content of 35 to 65 weight percent, based on the total weight of the polycarbonate-siloxane copolymers, the composition comprising less than 1 weight percent of a polycarbonate-siloxane copolymer having a siloxane content of greater than 10 weight percent and less than 30 weight percent, and the first and second polycarbonate-siloxane copolymers each comprise bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units.

[0096] Aspect 11: The polycarbonate composition of any one of aspects 1-10, wherein a molded sample of the composition exhibits an L* value of 10 or less, when measured by the CIE Lab method using a 10 degree observer, D65 illuminant, specular reflection excluded, measured in reflection mode, and a sample having a thickness of 3.2 millimeters.

[0097] Embodiment 12: The polycarbonate composition of any one of embodiments 1-11, wherein a molded sample of the composition, after exposure to a sunscreen or insect repellent, exhibits a tensile strain at break that is at least 50% of the tensile strain at break of an unexposed reference sample.

[0098] Embodiment 13: The polycarbonate composition of any one of embodiments 1-12, wherein a molded sample of the composition exhibits a UL-94 flammability rating of V0 or V1 at a thickness of 1.5 millimeters or less, and preferably a UL-94 flammability rating of V0 or V1 at a thickness of 1.2 millimeters or less.

[0099] Embodiment 14: A method of making the polycarbonate composition of any one of embodiments 1-13, comprising melt-mixing the components of the composition and, optionally, extruding the composition.

[0100] Embodiment 15: An article comprising the polycarbonate composition of any one of embodiments 1-13.

[0101] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of any suitable material, step, or ingredient disclosed herein. The compositions, methods, and articles can additionally or alternatively be formulated to be devoid of, or substantially free of, any material (or species), step, or ingredient that is not otherwise necessary to achieve the function or purpose of the compositions, methods, and articles.

[0102] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. "Combinations" include blends, mixtures, alloys, reaction products, and the like. Terms such as "first," "second," and the like do not denote order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a," "an," and "the" do not denote limitations of quantity and should be interpreted as encompassing both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. "Or" means "and / or" unless otherwise stated. References throughout this specification to "one embodiment" mean that a particular element described in connection with an embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. As used herein, the term "combinations thereof" includes one or more of the listed elements and is open, allowing for the presence of one or more similar elements not specified. Furthermore, it should be understood that the listed elements may be combined in any suitable manner in the various embodiments.

[0103] Unless otherwise specified herein, all test standards are the latest standards in effect as of the filing date of this application or, if priority is claimed, as of the filing date of the earliest priority application in which the test standard appears.

[0104] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in this application contradicts or conflicts with a term in the incorporated reference, the term in this application shall take precedence over the conflicting term in the incorporated reference.

[0105] Compounds are described using standard nomenclature. For example, any position not substituted by a indicated group is understood to have its valence filled by the indicated bond or hydrogen atom. A dash ("-") that is not between two letters or symbols is used to indicate the point of attachment of a substituent. For example, -CHO is attached through the carbon of a carbonyl group.

[0106] As used herein, the term "hydrocarbyl," whether used by itself or as a prefix, suffix, or fragment of another term, refers to a residue containing only carbon and hydrogen. The residue may be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. The residue may also contain a combination of aliphatic, aromatic, straight-chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when a hydrocarbyl residue is described as substituted, the hydrocarbyl residue may optionally contain heteroatoms above and beyond the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue may also contain one or more carbonyl groups, amino groups, hydroxyl groups, etc., or may contain heteroatoms within the backbone of the hydrocarbyl residue. The term "alkyl" refers to a branched or straight-chain saturated aliphatic hydrocarbon group, e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, s-pentyl, and n- and s-hexyl. "Alkenyl" refers to a straight- or branched-chain monovalent hydrocarbon group having at least one carbon-carbon double bond (e.g., ethenyl (-HC=CH2)). "Alkoxy" refers to an alkyl group linked through oxygen (i.e., alkyl-O-), e.g., methoxy, ethoxy, and sec-butyloxy groups. "Alkylene" refers to a straight- or branched-chain saturated divalent aliphatic hydrocarbon group (e.g., methylene (-CH2-) or propylene (-(CH2)3-)). "Cycloalkylene" refers to a divalent cyclic alkylene group, -C n H 2n-xwhere x is the number of hydrogens replaced by cyclization. "Cycloalkenyl" refers to a monovalent group having one or more rings and one or more carbon-carbon double bonds within the ring, where all ring members are carbon (e.g., cyclopentyl and cyclohexyl). "Aryl" refers to an aromatic hydrocarbon group containing a specified number of carbon atoms, such as phenyl, tropone, indanyl, or naphthyl. "Arylene" refers to a divalent aryl group. "Alkylarylene" refers to an arylene group substituted with an alkyl group. "Arylalkylene" refers to an alkylene group substituted with an aryl group (e.g., benzyl). The prefix "halo" refers to a group or compound containing one or more fluoro, chloro, bromo, or iodo substituents. Combinations of different halo atoms (e.g., bromo and fluoro) or only chloro atoms may be present. The prefix "hetero" means that the compound or group contains at least one ring member that is a heteroatom (e.g., 1, 2, or 3 heteroatoms), each heteroatom being independently N, O, S, Si, or P. "Substituted" means that the compound or group contains, each independently, a C, in place of a hydrogen. 1-9 Alkoxy, C 1-9 Haloalkoxy, nitro (-NO2), cyano (-CN), C 1-6 Alkylsulfonyl (-S(=O)2-alkyl), C 6-12 Arylsulfonyl (-S(=O)2-aryl), thiol (-SH), thiocyano (-SCN), tosyl (CH3C6H4SO2-), C 3-12 Cycloalkyl, C 2-12 Alkenyl, C 5-12 Cycloalkenyl, C 6-12 Aryl, C 7-13 Aryl alkylene, C 4-12 Heterocycloalkyl, and C 3-12 Heteroaryl means substituted with at least one (e.g., 1, 2, 3, or 4) substituents, which may be heteroaryl, provided that the valence of the substituted atom is not exceeded. The number of carbon atoms shown in the group excludes any optional substituents. For example, -CHCHCN is a C alkyl group substituted with a nitrile.

[0107] While particular embodiments have been described, presently unforeseen or unforeseeable alternatives, modifications, variations, improvements, and substantial equivalents may occur to applicant or others skilled in the art. Accordingly, the appended claims as filed, and as they may be amended, are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. 1. A polycarbonate composition comprising: 20 to 80 weight percent of bisphenol A homopolycarbonate; 10 to 55 weight percent of a first polycarbonate-siloxane copolymer having a siloxane content of 4 to 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer; 10 to 25 weight percent of a second polycarbonate-siloxane copolymer having a siloxane content of greater than 30 weight percent to 70 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer; Including, the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of less than 2 when the composition has a total siloxane content of 2 to 7.5%; and when the composition has a total siloxane content of greater than 7.5% to 15%, the first polycarbonate-siloxane copolymer and the second polycarbonate-siloxane copolymer are present in a weight ratio of 2 to 5; Polycarbonate composition.

2. 10. The polycarbonate composition of claim 1, wherein the bisphenol A homopolycarbonate has a weight average molecular weight of 18,000 to 40,000 grams per mole as determined by gel permeation chromatography against linear bisphenol A polycarbonate standards.

3. the first polycarbonate-siloxane copolymer has a siloxane content of from 4 to less than 10 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer; and the first polycarbonate-siloxane copolymer is present in an amount of 15 to 45 weight percent, based on the total weight of the composition; The polycarbonate composition according to claim 1 or 2.

4. 10. The polycarbonate composition of claim 1, wherein the second polycarbonate-siloxane copolymer has a siloxane content of 35 to 65 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer.

5. 10. The polycarbonate composition of claim 1, wherein the second polycarbonate-siloxane copolymer is present in the composition in an amount of greater than 15 to 25 weight percent, based on the total weight of the composition.

6. 2. The polycarbonate composition of claim 1, wherein the first and second polycarbonate-siloxane copolymers each comprise bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units.

7. 10. The polycarbonate composition of claim 1, wherein the second polycarbonate-siloxane copolymer has a weight average molecular weight of 21,000 to 50,000 g / mol as determined by gel permeation chromatography using a cross-linked styrene-divinylbenzene column at a sample concentration of 1 milligram per milliliter and calibrated with bisphenol A polycarbonate standards.

8. the polycarbonate composition further comprising 0.1 to 10 weight percent of an additive composition, based on the total weight of the polycarbonate composition; The polycarbonate composition of claim 1.

9. 50 to 60 weight percent of said bisphenol A homopolycarbonate; 25 to 35 weight percent of the first polycarbonate-siloxane copolymer; 15 to 20 weight percent of the second polycarbonate-siloxane copolymer; 10. The polycarbonate composition of claim 1, comprising:

10. the bisphenol A homopolycarbonate having a weight average molecular weight of 28,000 to 38,000 grams per mole as determined by gel permeation chromatography against a linear bisphenol A polycarbonate standard; the first polycarbonate-siloxane copolymer has a siloxane content of 4 to 8 weight percent, based on the total weight of the first polycarbonate-siloxane copolymer; the second polycarbonate-siloxane copolymer has a siloxane content of 35 to 65 weight percent, based on the total weight of the second polycarbonate-siloxane copolymer; the composition comprises less than 1 weight percent of a polycarbonate-siloxane copolymer having a siloxane content of greater than 10 weight percent and less than 30 weight percent; and the first and second polycarbonate-siloxane copolymers each comprise bisphenol A carbonate repeat units and poly(dimethylsiloxane) repeat units; The polycarbonate composition of claim 9.

11. 10. The polycarbonate composition of claim 1, wherein a molded sample of the composition exhibits an L* value of 10 or less when measured by CIE Lab method using a 10 degree observer, D65 illuminant, specular reflection excluded, measured in reflection mode, and a sample having a thickness of 3.2 millimeters.

12. 10. The polycarbonate composition of claim 1, wherein a molded sample of the composition exhibits a tensile strain at break, after exposure to a sunscreen or insect repellent, that is at least 50% of the tensile strain at break of an unexposed reference sample.

13. 10. The polycarbonate composition of claim 1, wherein a molded sample of the composition exhibits a UL-94 flammability rating of V0 or V1 at a thickness of 1.5 millimeters or less.

14. 10. A method for making the polycarbonate composition of claim 1, comprising melt-mixing the components of said composition.

15. An article comprising the polycarbonate composition of claim 1.

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