Patent Description:
Polycarbonates are useful in the manufacture of articles and components for a wide range of applications, from automotive parts to electronic appliances. Because of their broad use, it is desirable to provide polycarbonates with improved weathering performance and flame resistance. Previous efforts towards reducing the effects of weathering have included a coating having a high concentration of UV absorbing additives. For example, <CIT> relates to balance among low-temperature impact performance, flame-retardancy, hydrolytic stability, anti-UV performance, and heat resistance for polycarbonate compounds for outdoor applications. The example IE3 describes compositions comprising a polycarbonate (<NUM>%), a polysiloxane-carbonate copolymer (<NUM>%) having a siloxane content of <NUM>,<NUM>%, a phosphazene compound (<NUM>%) and a benzotriazole (<NUM>,<NUM>%) as a UV absorbing compound. It would be advantageous to provide polycarbonate compositions capable of resisting weathering effects without the need for a separate coating.

There accordingly remains a need in the art for thermoplastic compositions that have improved weathering performance and flame resistance. It would be a further advantage if thermoplastic compositions had good low-temperature impact resistance.

A polycarbonate composition comprises <NUM> to <NUM> weight percent of a polycarbonate; <NUM> to <NUM> weight percent of a polycarbonate-siloxane copolymer having a siloxane content of <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate-siloxane copolymer; <NUM> to <NUM> weight percent of a triazine-containing UV absorbing agent; and <NUM> to <NUM> weight percent of a phosphazene flame retardant; wherein weight percent of each component is based on the total weight of the composition.

A method of making the polycarbonate composition comprises melt-mixing the components of the composition, and, optionally, extruding the composition.

Another aspect is an article comprising the composition.

The above described and other features are exemplified by the following detailed description.

The present inventors have discovered that a desirable combination of properties can be obtained with a polycarbonate composition having particular amounts of a polycarbonate, a polycarbonate-siloxane copolymer, a triazine-containing UV absorbing agent, and phosphazene flame retardant. The resulting composition can advantageously exhibit a combination of good UV resistance, flame retardance, and low temperature impact properties. A significant improvement is therefore provided by the present disclosure.

Accordingly, an aspect of the present disclose is a polycarbonate composition. The polycarbonate composition comprises a polycarbonate. "Polycarbonate" as used herein means a homopolymer or copolymer having repeating structural carbonate units of formula (<NUM>)
<CHM>
wherein at least <NUM> percent of the total number of R<NUM> groups are aromatic, or each R<NUM> contains at least one C<NUM>-<NUM> aromatic group. Preferably, each R<NUM> can be derived from a dihydroxy compound such as an aromatic dihydroxy compound of formula (<NUM>) or a bisphenol of formula (<NUM>). <CHM>
In formula (<NUM>), each Rh is independently a halogen atom, for example bromine, a C<NUM>-<NUM> hydrocarbyl group such as a C<NUM>-<NUM> alkyl, a halogen-substituted C<NUM>-<NUM> alkyl, a C<NUM>-<NUM> aryl, or a halogen-substituted C<NUM>-<NUM> aryl, and n is <NUM> to <NUM>.

In formula (<NUM>), Ra and Rb are each independently a halogen, C<NUM>-<NUM> alkoxy, or C<NUM>-<NUM> alkyl, and p and q are each independently integers of <NUM> to <NUM>, such that when p or q is less than <NUM>, the valence of each carbon of the ring is filled by hydrogen. In an aspect, p and q is each <NUM>, or p and q is each <NUM>, and Ra and Rb are each a C<NUM>-<NUM> alkyl group, preferably methyl, disposed meta to the hydroxy group on each arylene group. Xa is a bridging group connecting the two hydroxy-substituted aromatic groups, where the bridging group and the hydroxy substituent of each C<NUM> arylene group are disposed ortho, meta, or para (preferably para) to each other on the C<NUM> arylene group, for example, a single bond, -O-, -S-, -S(O)-, -S(O)<NUM>-, -C(O)-, or a C<NUM>-<NUM> organic group, which can be cyclic or acyclic, aromatic or non-aromatic, and can further comprise heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. For example, Xa can be a substituted or unsubstituted C<NUM>-<NUM> cycloalkylidene; a C<NUM>-<NUM> alkylidene of the formula -C(Rc)(Rd) - wherein Rc and Rd are each independently hydrogen, C<NUM>-<NUM> alkyl, C<NUM>-<NUM> cycloalkyl, C<NUM>-<NUM> arylalkyl, C<NUM>-<NUM> heteroalkyl, or cyclic C<NUM>-<NUM> heteroarylalkyl; or a group of the formula -C(=Re)- wherein Re is a divalent C<NUM>-<NUM> hydrocarbon group.

Examples of bisphenol compounds include <NUM>,<NUM>'-dihydroxybiphenyl, <NUM>,<NUM>-dihydroxynaphthalene, <NUM>,<NUM>-dihydroxynaphthalene, bis(<NUM>-hydroxyphenyl)methane, bis(<NUM>-hydroxyphenyl)diphenylmethane, bis(<NUM>-hydroxyphenyl)-<NUM>-naphthylmethane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)ethane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>-phenylethane, <NUM>-(<NUM>-hydroxyphenyl)-<NUM>-(<NUM>-hydroxyphenyl)propane, bis(<NUM>-hydroxyphenyl)phenylmethane, <NUM>,<NUM>-bis(<NUM>-hydroxy-<NUM>-bromophenyl)propane, <NUM>,<NUM>-bis (hydroxyphenyl)cyclopentane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)cyclohexane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)isobutene, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)cyclododecane, trans-<NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>-butene, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)adamantane, alpha,alpha'-bis(<NUM>-hydroxyphenyl)toluene, bis(<NUM>-hydroxyphenyl)acetonitrile, <NUM>,<NUM>-bis(<NUM>-methyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-ethyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-n-propyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-isopropyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-sec-butyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-t-butyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-cyclohexyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-allyl-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-methoxy-<NUM>-hydroxyphenyl)propane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)hexafluoropropane, <NUM>,<NUM>-dichloro-<NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)ethylene, <NUM>,<NUM>-dibromo-<NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)ethylene, <NUM>,<NUM>-dichloro-<NUM>,<NUM>-bis(<NUM>-phenoxy-<NUM>-hydroxyphenyl)ethylene, <NUM>,<NUM>'-dihydroxybenzophenone, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>-butanone, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>,<NUM>-hexanedione, ethylene glycol bis(<NUM>-hydroxyphenyl)ether, bis(<NUM>-hydroxyphenyl)ether, bis(<NUM>-hydroxyphenyl)sulfide, bis(<NUM>-hydroxyphenyl)sulfoxide, bis(<NUM>-hydroxyphenyl)sulfone, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)fluorene, <NUM>,<NUM>-dihydroxypyrene, <NUM>,<NUM>'-dihydroxy-<NUM>,<NUM>,<NUM>',<NUM>'- tetramethylspiro(bis)indane ("spirobiindane bisphenol"), <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)phthalimide, <NUM>,<NUM>-dihydroxydibenzo-p-dioxin, <NUM>,<NUM>-dihydroxythianthrene, <NUM>,<NUM>-dihydroxyphenoxathin, <NUM>,<NUM>-dihydroxy-<NUM>,<NUM>-dimethylphenazine, <NUM>,<NUM>-dihydroxydibenzofuran, <NUM>,<NUM>-dihydroxydibenzothiophene, and <NUM>,<NUM>-dihydroxycarbazole; resorcinol, substituted resorcinol compounds such as <NUM>-methyl resorcinol, <NUM>-ethyl resorcinol, <NUM>-propyl resorcinol, <NUM>-butyl resorcinol, <NUM>-t-butyl resorcinol, <NUM>-phenyl resorcinol, <NUM>-cumyl resorcinol, <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoro resorcinol, <NUM>,<NUM>,<NUM>,<NUM>-tetrabromo resorcinol, or the like; catechol; hydroquinone; substituted hydroquinones such as <NUM>-methyl hydroquinone, <NUM>-ethyl hydroquinone, <NUM>-propyl hydroquinone, <NUM>-butyl hydroquinone, <NUM>-t-butyl hydroquinone, <NUM>-phenyl hydroquinone, <NUM>-cumyl hydroquinone, <NUM>,<NUM>,<NUM>,<NUM>-tetramethyl hydroquinone, <NUM>,<NUM>,<NUM>,<NUM>-tetra-t-butyl hydroquinone, <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoro hydroquinone, <NUM>,<NUM>,<NUM>,<NUM>-tetrabromo hydroquinone, or the like.

Specific dihydroxy compounds include resorcinol, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) propane ("bisphenol A" or "BPA"), <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) phthalimidine, <NUM>-phenyl-<NUM>,<NUM>'-bis(<NUM>-hydroxyphenyl) phthalimidine (also known as N-phenyl phenolphthalein bisphenol, "PPPBP", or <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>-phenylisoindolin-<NUM>-one), <NUM>,<NUM>-bis(<NUM>-hydroxy-<NUM>-methylphenyl)cyclohexane, and <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)-<NUM>,<NUM>,<NUM>-trimethylcyclohexane (isophorone bisphenol).

In an aspect, the polycarbonate comprises a bisphenol A polycarbonate homopolymer, also referred to as a bisphenol A homopolycarbonate. The bisphenol A polycarbonate homopolymer has repeating structural carbonate units of the formula (<NUM>). <CHM>
Bisphenol A polycarbonate homopolymers can be manufactured by processes such as interfacial polymerization and melt polymerization, which are known, and are described, for example, in <CIT> and <CIT>, from bisphenol A ((<NUM>,<NUM>-bis(<NUM>-hydroxyphenyl)propane, or BPA). An endcapping agent can be included during polymerization to provide end groups, for example monocyclic phenols such as phenol, p-cyanophenol, and C<NUM>-<NUM> alkyl-substituted phenols such as p-cumyl-phenol, resorcinol monobenzoate, and p-tertiarybutyl phenol, 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 mono-chloroformates such as phenyl chloroformate, alkyl-substituted phenyl chloroformates, p-cumyl phenyl chloroformate, and toluene chloroformate. Phenol and para-cumylphenol are specifically mentioned. Combinations of different endcapping agents can be used. Branched polycarbonate blocks can be prepared by adding a branching agent during polymerization, for example trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxyphenylethane, isatin-bis-phenol, tris-phenol TC (<NUM>,<NUM>,<NUM>-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA (<NUM>(<NUM>(<NUM>,<NUM>-bis(p-hydroxyphenyl)-ethyl) alpha, alpha-dimethyl benzyl)phenol), <NUM>-chloroformyl phthalic anhydride, trimesic acid, and benzophenone tetracarboxylic acid. The branching agents can be added at a level of <NUM> to <NUM> weight percent (wt%), for example, <NUM> to <NUM> wt%. Combinations comprising linear polycarbonates and branched polycarbonates can be used.

The bisphenol A polycarbonate homopolymer can be a linear bisphenol A polycarbonate homopolymer, optionally endcapped with phenol or para-cumylphenol, and having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole (g/mol), preferably <NUM>,<NUM> to <NUM>,<NUM>/mol, as measured by gel permeation chromatography (GPC), using a crosslinked styrene-divinylbenzene column and calibrated to bisphenol A polycarbonate references. GPC samples are prepared at a concentration of <NUM> milligram per milliliter (mg/mL) and are eluted at a flow rate of <NUM> per minute. The bisphenol A polycarbonate homopolymer can comprise a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by GPC. The bisphenol A polycarbonate homopolymer can comprise a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by GPC.

In an aspect, more than one bisphenol A polycarbonate homopolymer can be present. For example, the bisphenol A polycarbonate homopolymer can comprise a first bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>/mol or <NUM>,<NUM> to <NUM>,<NUM>/mol or <NUM>,<NUM> to <NUM>,<NUM>/mol, and a second bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>/mol or <NUM>,<NUM> to <NUM>,<NUM>/mol, each measured by GPC using BPA homopolycarbonate standards. The weight ratio of the first bisphenol A polycarbonate homopolymer relative to the second bisphenol A polycarbonate homopolymer can be <NUM>:<NUM> to <NUM>:<NUM>, for example <NUM>:<NUM> to <NUM>: <NUM>, or <NUM>:<NUM> to <NUM>:<NUM>, or <NUM>:<NUM> to <NUM>:<NUM>.

The polycarbonate can be present in an amount of <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate composition. Within this range, the polycarbonate can be present in an amount of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent.

In addition to the polycarbonate, the composition comprises a polycarbonate-siloxane copolymer. Polycarbonate-siloxane copolymers are also known as polycarbonate-siloxanes. The polycarbonate-siloxane copolymer comprises carbonate repeat units and siloxane units. The carbonate units can be derived from an aromatic dihydroxy compound of formula (<NUM>) or a bisphenol of formula (<NUM>), as described above.

In an aspect the carbonate units can be bisphenol carbonate units derived from bisphenols of formula (<NUM>). A preferred bisphenol is BPA.

The siloxane units (also referred to as polysiloxane blocks) are optionally of formula (<NUM>)
<CHM>
wherein each R is independently a C<NUM>-<NUM> monovalent organic group. For example, R can be a C<NUM>-<NUM> alkyl, C<NUM>-<NUM> alkoxy, C<NUM>-<NUM> alkenyl, C<NUM>-<NUM> alkenyloxy, C<NUM>-<NUM> cycloalkyl, C<NUM>-<NUM> cycloalkoxy, C<NUM>-<NUM> aryl, C<NUM>-<NUM> aryloxy, C<NUM>-<NUM> arylalkylene, C<NUM>-<NUM> arylalkylenoxy, C<NUM>-<NUM> alkylarylene, or C<NUM>-<NUM> alkylarylenoxy. The foregoing groups can be fully or partially halogenated with fluorine, chlorine, bromine, or iodine, or a combination thereof. In an aspect, where a transparent poly(carbonate-siloxane) is desired, R is unsubstituted by halogen. Combinations of the foregoing R groups can be used in the same copolymer.

In an aspect, R is a C<NUM>-<NUM> alkyl, C<NUM>-<NUM> alkoxy, C<NUM>-<NUM> cycloalkyl, C<NUM>-<NUM> cycloalkoxy, C<NUM>-<NUM> aryl, C<NUM>-<NUM> aryloxy, C<NUM> arylalkylene, C<NUM> arylalkylenoxy, C<NUM> alkylarylene, or C<NUM> alkylarylenoxy. In an aspect, R is methyl, trifluoromethyl, or phenyl, preferably methyl.

The value of E in formula (<NUM>) can vary widely depending on the type and relative amount of each component in the polycarbonate composition, the desired properties of the composition, and like considerations. Generally, E has an average value of <NUM> to <NUM>,<NUM>, or <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>. In an aspect, E has an average value of <NUM> to <NUM> or <NUM> to <NUM>, in still another aspect, E has an average value of <NUM> to <NUM> or <NUM> to <NUM>, and in yet another aspect, E has an average value of <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>.

In an aspect, the siloxane units are of formula (<NUM>)
<CHM>
wherein E is as defined above in the context of formula (<NUM>); each R can be the same or different, and is as defined above in the context of formula (<NUM>); and Ar can be the same or different, and is a substituted or unsubstituted C<NUM>-<NUM> arylene, wherein the bonds are directly connected to an aromatic moiety. Ar groups in formula (<NUM>) can be derived from a C<NUM>-<NUM> dihydroxyarylene compound, for example a dihydroxy compound of formula (<NUM>). Exemplary dihydroxyarylene compounds are <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) methane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) ethane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) propane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) butane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) octane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) propane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) n-butane, <NUM>,<NUM>-bis(<NUM>-hydroxy-<NUM>-methylphenyl) propane, <NUM>,<NUM>-bis(<NUM>-hydroxyphenyl) cyclohexane, bis(<NUM>-hydroxyphenyl sulfide), and <NUM>,<NUM>-bis(<NUM>-hydroxy-t-butylphenyl) propane, or a combination thereof.

Specific examples of siloxane units of formula (<NUM>) include those of the formulas (6a) and (6b).

In an aspect, the siloxane units are of formula (<NUM>)
<CHM>
wherein Rand E are as described above in the context of formula (<NUM>), and each R<NUM> is independently a divalent C<NUM>-<NUM> organic group, and wherein the polymerized polysiloxane unit is the reaction residue of its corresponding dihydroxy compound. In an aspect, the polydiorganosiloxane blocks are of formula (<NUM>):
<CHM>
wherein R and E are as defined above in the context of formula (<NUM>). R<NUM> in formula (<NUM>) is a divalent C<NUM>-<NUM> aliphatic group. Each M in formula (<NUM>) can be the same or different, and can be a halogen, cyano, nitro, C<NUM>-<NUM> alkylthio, C<NUM>-<NUM> alkyl, C<NUM>-<NUM> alkoxy, C<NUM>-<NUM> alkenyl, C<NUM>-<NUM> alkenyloxy, C<NUM>-<NUM> cycloalkyl, C<NUM>-<NUM> cycloalkoxy, C<NUM>-<NUM> aryl, C<NUM>-<NUM> aryloxy, C<NUM>-<NUM> aralkyl, C<NUM>-<NUM> arylalkylenoxy, C<NUM>-<NUM> alkylarylene, or C<NUM>-<NUM> alkylarylenoxy, wherein each n is independently <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

In an aspect, M is bromo or chloro, an alkyl such as methyl, ethyl, or propyl, an alkoxy such as methoxy, ethoxy, or propoxy, or an aryl such as phenyl, chlorophenyl, or tolyl; R<NUM> is a dimethylene, trimethylene or tetramethylene; and R is a C<NUM>-<NUM> alkyl, haloalkyl such as trifluoropropyl, cyanoalkyl, or aryl such as phenyl, chlorophenyl or tolyl. In an aspect, R is methyl, or a combination of methyl and trifluoropropyl, or a combination of methyl and phenyl. In an aspect, R is methyl, M is methoxy, n is one, and R<NUM> is a divalent C<NUM>-<NUM> aliphatic group. Specific polydiorganosiloxane blocks are of the formula
<CHM>
<CHM>
or a combination thereof, wherein E has an average value of <NUM> to <NUM>, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, or <NUM> to <NUM>.

Blocks of formula (<NUM>) can be derived from the corresponding dihydroxy polydiorganosiloxanes by known methods. The polycarbonate-siloxane can be manufactured by introducing phosgene under interfacial reaction conditions into a mixture of bisphenol and an end capped polydimethylsiloxane (PDMS). Other known methods can also be used.

In an aspect, the poly(carbonate-siloxane) comprises carbonate units derived from bisphenol A, and repeating siloxane units (6a), (6b), (8a), (8b), (8c), or a combination thereof (preferably of formula 8a), wherein E has an average value of <NUM> to <NUM>, preferably <NUM> to <NUM>, or <NUM> to <NUM>, more preferably <NUM> to <NUM> or <NUM> to <NUM>.

The polycarbonate-siloxane copolymer can have a siloxane content of <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate-siloxane copolymer. Within this range, the polycarbonate-siloxane copolymer can have a siloxane content of <NUM> to <NUM> weight percent, or greater than <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or greater than <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent. As used herein, "siloxane content" of a poly(carbonate-siloxane) refers to the content of siloxane units based on the total weight of the polycarbonate-siloxane copolymer.

The polycarbonate-siloxane copolymer can have a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM>/mol, preferably <NUM>,<NUM> to <NUM>,<NUM>/mol, more preferably <NUM>,<NUM> to <NUM>,<NUM>/mol as measured by gel permeation chromatography using a crosslinked styrene-divinyl benzene column, at a sample concentration of <NUM> milligram per milliliter, and as calibrated with bisphenol A polycarbonate standards.

In an aspect, the composition comprises less than or equal to <NUM> weight percent or less than or equal to <NUM> weight percent, or less than or equal to <NUM> weight percent of a polycarbonate-siloxane having a siloxane content of less than <NUM> weight percent. Preferably a polycarbonate-siloxane having a siloxane content of less than <NUM> weight percent is excluded from the composition. In an aspect, the composition comprises less than or equal to <NUM> weight percent or less than or equal to <NUM> weight percent, or less than or equal to <NUM> weight percent of a polycarbonate-siloxane having a siloxane content of greater than <NUM> weight percent. Preferably a polycarbonate-siloxane having a siloxane content of greater than <NUM> weight percent is excluded from the composition.

The polycarbonate-siloxane copolymer can be present in the composition in an amount to provide a total siloxane content of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent or <NUM> to <NUM> weight percent, each based on the total weight of the polycarbonate composition.

The polycarbonate-siloxane copolymer can be present in the composition an amount of <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate composition. Within this range, the polycarbonate-siloxane copolymer can be present in an amount of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent.

In addition to the polycarbonate and the polycarbonate-siloxane copolymer, the polycarbonate composition further comprises a triazine-containing UV absorbing agent. In an aspect, the triazine-containing UV absorbing agent can comprise a trisaryl-<NUM>,<NUM>,<NUM>-triazine UV absorbing agent. The triazine-containing UV absorbing agent has a triazine core
<CHM>
Including, for example, <NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)-<NUM>-[(hexyl)oxy]-phenol (CAS Reg. No. <NUM>-<NUM>-<NUM>, commercially available as CHIGUARD <NUM> from Chitec Technology), and <NUM>-[<NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylphenyl)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]-<NUM>-(octyloxy)phenol (CAS Reg. No. <NUM>-<NUM>-<NUM>, commercially available as CHIGUARD <NUM> from Chitec Technology).

In a specific aspect, the triazine-containing UV absorbing agent can comprise <NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)-<NUM>-[(hexyl)oxy]-phenol, <NUM>-[<NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylphenyl)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]-<NUM>-(octyloxy)phenol, or a combination thereof, preferably <NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)-<NUM>-[(hexyl)oxy]-phenol.

The triazine-containing UV absorbing agent can be present in the composition in an amount of <NUM> to <NUM> weight percent, based on the total weight of the composition. Within this range, the triazine-containing UV absorbing agent can be present in an amount of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent.

The composition can minimize or exclude other UV absorbing agents. For example, the composition can comprise less than <NUM> weight percent, or less than <NUM> weight percent, or less than <NUM> weight percent, or less then <NUM> weight percent, or less than <NUM> weight percent of a UV absorbing agent other than a triazine-containing UV absorbing agent. In an aspect the composition can comprise less than <NUM> weight percent, or less than <NUM> weight percent, or less than <NUM> weight percent, or less than <NUM> weight percent, or less than <NUM> weight percent of a benzotriazole-containing UV absorbing agent. As used herein, "benzotriazole-containing UV absorbing agent" refers to those comprising a benzotriazole core
<CHM>
including, for example, <NUM>-(<NUM>-hydroxy-<NUM>,<NUM>-di-cumyl)benzotriazole (CAS Reg. No. <NUM>-<NUM>-<NUM>, commercially available as TINUVIN <NUM> from BASF), and <NUM>,<NUM>'-methylene-bis(<NUM>-(<NUM>-benzotriazol-<NUM>-yl)-<NUM>-(<NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl)) phenol (CAS Reg. No. <NUM>-<NUM>-<NUM>, commercially available as TINUVIN <NUM> from BASF or CHIGUARD <NUM> from Chitec Technology).

The polycarbonate composition further comprises a phosphazene flame retardant. Phosphazenes (<NUM>) and cyclic phosphazenes (<NUM>)
<CHM>
in particular can be used, wherein w1 is <NUM> to <NUM>,<NUM> and w2 is <NUM> to <NUM>, preferably <NUM> to <NUM>, and each Rw is independently a C<NUM>-<NUM> alkyl, alkenyl, alkoxy, aryl, aryloxy, or polyoxyalkylene. In the foregoing groups at least one hydrogen atom of these groups can be substituted with a group having an N, S, O, or F atom, or an amino group. For example, each Rw can be a substituted or unsubstituted phenoxy, an amino, or a polyoxyalkylene group. Any given Rw can further be a crosslink to another phosphazene group. Exemplary crosslinks include bisphenol groups, for example bisphenol A groups. Examples include phenoxy cyclotriphosphazene, octaphenoxy cyclotetraphosphazene decaphenoxy cyclopentaphosphazene, and the like. A combination of different phosphazenes can be used. A number of phosphazenes and their synthesis are described in H. Allcook, "Phosphorus-Nitrogen Compounds" Academic Press (<NUM>), and J. Mark et al. , "Inorganic Polymers" Prentice-Hall International, Inc.

In an aspect, the phosphazene flame retardant can comprise a cyclic phosphazene. In an aspect, the phosphazene flame retardant comprises phenoxy cyclotriphosphazene, octaphenoxy cyclotetraphosphazene decaphenoxy cyclopentaphosphazene, hexaphenoxycyclotriphosphazene or a combination thereof. In an aspect, the phosphazene can comprise hexaphenoxycyclotriphosphazene.

The phosphazene flame retardant can be present in an amount of <NUM> to <NUM> weight percent, based on the total weight of the composition. Within this range, the phosphazene flame retardant can be present in an amount of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent.

The polycarbonate composition can optionally further comprise an additive composition comprising one or more additives ordinarily 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. Additives can include fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, plasticizers, lubricants, mold release agents, antistatic agents, colorants such as such as titanium dioxide, carbon black, and organic dyes, surface effect additives, radiation stabilizers, flame retardants, and anti-drip agents. A combination of additives can be used, for example a combination of a heat stabilizer, mold release agent, and ultraviolet light stabilizer. In general, the additives are used in the amounts generally known to be effective. For example, the total amount of the additives (other than any impact modifier, filler, or reinforcing agents) can be <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate composition. In an aspect, the polycarbonate composition comprises no more than <NUM> weight percent based on the weight of the composition of a processing aid, a heat stabilizer, an antioxidant, a colorant, or a combination thereof.

The polycarbonate composition can optionally exclude other components not specifically described herein. For example, the polycarbonate composition can exclude thermoplastic polymers other than the polycarbonate (e.g., the bisphenol A homopolycarbonate), and the polycarbonate-siloxane copolymer. For example the composition can minimize or exclude polyesters (e.g., a polyester can be present in an amount of <NUM> weight percent or less, preferably wherein a polyester is excluded from the composition). The composition can optionally exclude a polycarbonate other than a bisphenol A homopolycarbonate and the polycarbonate-siloxane copolymer having a siloxane content of <NUM> to <NUM> weight percent based on the total weight of the polycarbonate-siloxane copolymer. For example a polyester-carbonate or a bisphenol A copolycarbonate different from the polycarbonate-siloxane copolymer can be minimized or excluded from the composition (e.g., can be present in an amount of <NUM> weight percent or less, preferably excluded from the composition). The polycarbonate composition can optionally exclude impact modifiers, for example silicone-based impact modifiers different from the poly(carbonate-siloxane) copolymer, methyl methacrylate-butadiene-styrene copolymers, acrylonitrile-butadiene, styrene copolymers, and the like, or a combination thereof. The composition can exclude halogenated flame retardants, for example brominated flame retardants, including brominated polycarbonate (e.g., a polycarbonate containing brominated carbonate includes units derived from <NUM>,<NUM>',<NUM>,<NUM>'-tetrabromo-<NUM>,<NUM>'-isopropylidenediphenol (TBBPA) and carbonate units derived from at least one dihydroxy aromatic compound that is not TBBPA), brominated epoxies, and the like or combinations thereof. The composition can optionally exclude inorganic flame retardants.

In an aspect, the polycarbonate (e.g., a bisphenol A homopolycarbonate), the polycarbonate-siloxane copolymer, the triazine-containing UV absorbing agent and the phosphazene flame retardant sum to at least <NUM> weight percent, or at least <NUM> weight percent, or at least <NUM> weight percent, or at least <NUM> weight percent, or at least <NUM> weight percent, or at least <NUM> weight percent of the total weight of the polycarbonate composition.

In a specific aspect, the polycarbonate composition can comprise <NUM> to <NUM> weight percent of a polycarbonate; <NUM> to <NUM> weight percent of a polycarbonate-siloxane copolymer having a siloxane content of <NUM> to <NUM> weight percent based on the total weight of the polycarbonate-siloxane copolymer; <NUM> to <NUM> weight percent of a triazine-containing UV absorbing agent; and <NUM> to <NUM> weight percent of a phosphazene flame retardant. The polycarbonate can be a bisphenol A homopolymer comprising a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards, and a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards. The polycarbonate-siloxane copolymer can comprise bisphenol A carbonate repeating units and poly(dimethyl siloxane) repeating units and can have a siloxane content of <NUM> to <NUM> weight percent based on the total weight of the polycarbonate-siloxane copolymer. The triazine-containing UV absorbing agent can comprise <NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)-<NUM>-[(hexyl)oxy]-phenol. The phosphazene can be hexaphenoxycyclotriphosphazene.

The polycarbonate composition can exhibit one or more desirable properties. For example, it was found that improved color stability, flame performance, and low temperature impact strength can unexpectedly be obtained by combining a polycarbonate, preferably a bisphenol A polycarbonate homopolymer, a polycarbonate-siloxane copolymer, a triazine-containing UV absorbing agent, and a phosphazene flame retardant. Without wishing to be bound by theory, it is believed that the unexpected combination of color stability, flame retardance, and impact properties is achieved by careful selection of the triazine-containing UV absorbing agent and the phosphazene flame retardant used in the composition.

The polycarbonate composition can further have good flame retardant properties. In an aspect of measuring flame retardance, the UL94 standard utilizes a rating of V0, V1, V2 or HB, wherein a rating of V0 is better than V1 or V2 and is required for many applications at the actual part thickness. Using this standard, the polycarbonate compositions are formed into a molded article having a given thickness. The thinner the article, the more difficult it is to achieve a rating of V0 or V1. In an aspect, a molded sample of the polycarbonate composition is capable of achieving UL-<NUM> V0 rating at a thickness of <NUM> millimeters or less, preferably a UL-<NUM> rating of V0 at a thickness of less than or equal to <NUM> millimeters.

The polycarbonate composition can further have good impact properties, in particular Izod notched impact strength. In an aspect, the composition can have an Izod notched impact energy of at least <NUM> joules per meter measured at -<NUM> on a sample of <NUM> thickness according to ASTM D256-<NUM>.

The polycarbonate composition can further have a color shift (delta E) value of less than or equal to <NUM> after <NUM> days of exposure to UVA <NUM> at <NUM> W/m, measured according to ASTM G154 and a <NUM> thick molded sample of the polycarbonate composition.

In an aspect, the polycarbonate composition can advantageously exhibit the above UL-<NUM> rating, notched impact strength at a temperature of -<NUM>, and color shift.

The polycarbonate composition can comprise <NUM> to <NUM> weight percent of a polycarbonate; <NUM> to <NUM> weight percent of a polycarbonate-siloxane copolymer having a siloxane content of <NUM> to <NUM> weight percent based on the total weight of the polycarbonate-siloxane copolymer; <NUM> to <NUM> weight percent of a triazine-containing UV absorbing agent; and <NUM> to <NUM> weight percent of a phosphazene flame retardant; wherein weight percent of each component is based on the total weight of the composition. The polycarbonate can be a bisphenol A homopolymer, preferably comprising a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards, preferably the bisphenol A polycarbonate homopolymer can comprise a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards; or a linear bisphenol A polycarbonate homopolymer having a weight average molecular weight of <NUM>,<NUM> to <NUM>,<NUM> grams per mole, preferably <NUM>,<NUM> to <NUM>,<NUM> grams per mole, as determined by gel permeation chromatography relative to linear bisphenol A polycarbonate standards; or a combination thereof. The polycarbonate-siloxane copolymer can comprise bisphenol A carbonate repeating units and poly(dimethyl siloxane) repeating units. The polycarbonate-siloxane copolymer can have a siloxane content of <NUM> to <NUM> weight percent, or <NUM> to <NUM> weight percent based on the total weight of the polycarbonate-siloxane copolymer. The composition can comprise less than <NUM> weight percent, or less than <NUM> weight percent of a polycarbonate-siloxane copolymer having a siloxane content that is less than <NUM> weight percent based on the total weight of the polycarbonate siloxane, a polycarbonate-siloxane copolymer having a siloxane content that is greater than <NUM> weight percent based on the total weight of the polycarbonate siloxane, or both. Preferably the composition can be free of a polycarbonate-siloxane copolymer having a siloxane content that is less than <NUM> weight percent based on the total weight of the polycarbonate siloxane, a polycarbonate-siloxane copolymer having a siloxane content that is greater than <NUM> weight percent based on the total weight of the polycarbonate siloxane, or both. The triazine-containing UV absorbing agent can comprise a trisaryl-<NUM>,<NUM>,<NUM>-triazine UV absorbing agent, for example <NUM>-(<NUM>,<NUM>-diphenyl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl)-<NUM>-[(hexyl)oxy]-phenol or <NUM>-<NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylphenyl)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl-<NUM>-(octyloxy)phenol. The phosphazene flame retardant can comprise a phenoxy phosphazene, preferably a hexaphenoxycyclotriphosphazene. The polycarbonate composition can further comprise <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate composition, of an additive composition.

The polycarbonate composition can be manufactured by various methods known in the art. For example, powdered polycarbonate homopolymer, polycarbonate-siloxane, UV absorbing agent, and the phosphazene and other optional components are first blended, optionally with any fillers, in a high-speed mixer or by hand mixing. The blend is then fed into 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 at the throat and/or downstream through a side stuffer, or by being compounded into a masterbatch with a desired polymer and fed into the extruder. The extruder is generally operated at a temperature higher than that necessary to cause the composition to flow. The extrudate can be immediately quenched in a water bath and pelletized. The pellets so prepared can be one-fourth inch long or less as desired. Such pellets can be used for subsequent molding, shaping, or forming.

Shaped, formed, casted, or molded articles comprising the polycarbonate composition are also provided. The polycarbonate composition can be molded into useful shaped articles by a variety of methods, such as injection molding, extrusion, rotational molding, blow molding, and thermoforming. The article can be a molded article, a thermoformed article, an extruded film, an extruded sheet, a honeycomb structure, one or more layers of a multi-layer article, a substrate for a coated article, and a substrate for a metallized article. Exemplary articles can include computer and business machine housings such as housings for monitors, handheld electronic device housings such as housings for cell phones, electrical connectors, and components of lighting fixtures, ornaments, home appliances, roofs, greenhouses, sunrooms, swimming pool enclosures, electronic device casings and signs and the like. In addition, the polycarbonate compositions can be used for such applications as automotive panel and trim. Examples of suitable articles are exemplified by but are not limited to aircraft, automotive, truck, military vehicle (including automotive, aircraft, and water-borne vehicles), scooter, and motorcycle exterior and interior components, including panels, quarter panels, rocker panels, trim, fenders, doors, deck-lids, trunk lids, hoods, bonnets, roofs, bumpers, fascia, grilles, mirror housings, pillar appliqués, 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; enclosures, housings, panels, and parts for outdoor vehicles and devices; enclosures for electrical and telecommunication devices; outdoor furniture; aircraft components; boats and marine equipment, including trim, enclosures, and housings; outboard motor housings; depth finder housings; personal water-craft; jet-skis; pools; spas; hot tubs; steps; step coverings; building and construction applications such as glazing, roofs, windows, floors, decorative window furnishings or treatments; treated glass covers for pictures, paintings, posters, and like display items; wall panels, and doors; counter tops; protected graphics; outdoor and indoor signs; enclosures, housings, panels, and parts for automatic teller machines (ATM); computer; desk-top computer; portable computer; lap-top computer; hand held computer housings; monitor; printer; keyboards; FAX machine; copier; telephone; phone bezels; mobile phone; radio sender; radio receiver; enclosures, housings, panels, and parts for lawn and garden tractors, lawn mowers, and tools, including lawn and garden tools; window and door trim; sports equipment and toys; enclosures, housings, panels, and parts for snowmobiles; recreational vehicle panels and components; playground equipment; shoe laces; articles made from plastic-wood combinations; golf course markers; utility pit covers; light fixtures; lighting appliances; 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 textiles; coated painted articles; coated dyed articles; coated fluorescent articles; coated foam articles; and like applications. In an aspect, the article can be for telecommunications applications, for example for a fifth generation (<NUM>) communication article (e.g., a <NUM> base station, a <NUM> base station antenna housing, a <NUM> cell tower component, a <NUM> radome, etc.).

Materials used for the following examples are described in Table <NUM>.

The formulations were compounded on a Toshiba TEM-37BS extruder using an internal screw configuration of L-<NUM>-1B. The raw materials were blended and fed to the extruder via a throat feeder. A typical extrusion profile is shown in Table <NUM>.

Molded parts were injection molded using the typical injection molding conditions shown in Table <NUM>.

Sample preparation and testing methods are described in Table <NUM>.

Table <NUM> shows the compositions and properties for the compositions according to Examples <NUM>-<NUM>. Comparative examples are indicated with an asterisk.

The results in Table <NUM> show that higher loading of UV absorber decreases the delta E due to lower yellowing after UVA, UVB or Xenon light aging. However, the flame retardant performance is undesirably decreased with increased UV absorber. It was noted that triazine-type UV absorbers (TZN-<NUM>, TZN-<NUM>) provided better color retaining performance than benzotriazole type UV absorbers (BZT-<NUM>, BZT-<NUM>), which was more obvious in compositions having high UV absorber loading. For example, comparing compositions <NUM>* and <NUM>*, the UVA testing results after <NUM> days gave delta E of <NUM> and <NUM> respectively, indicating improved performance with a triazine UV agent.

To obtain the desired flame performance in combination with the UV stability, additional formulations were prepared according to Table <NUM>. As shown in Table <NUM>, the compositions according to Examples <NUM>-<NUM> include a phosphazene flame retardant.

As shown in Table <NUM>, the presence of PPZ (e.g., <NUM> to <NUM> weight percent) provided robust flame performance, achieving a rating of V0 at thicknesses of <NUM> and <NUM> millimeters. It was also noted that benzotriazole-type UV agents provided decreased low temperature impact performance, while equivalent loadings of triazine-type UV agents provided improved low temperature impact properties.

Compositions were further evaluated for low temperature impact performance and UV weathering color retention. The results are shown in Table <NUM>.

As shown in Table <NUM>, the presence of PPZ provided a more robust flame performance compared to KSS as the flame retardant, and further, better color retention was also observed after <NUM> days of UV-A exposure at <NUM>, <NUM> W/m<NUM> (no water spray). Higher loadings of PPZ (e.g., <NUM>% or more) were observed to reduce low temperature impact properties.

All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. "Combinations" is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms "first," "second," and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a" and "an" and "the" do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. "Or" means "and/or" unless clearly stated otherwise. Reference throughout the specification to "an aspect" means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term "combination thereof' as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements not named. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

As used herein, the term "hydrocarbyl", whether used by itself, or as a prefix, suffix, or fragment of another term, refers to a residue that contains only carbon and hydrogen. The residue can be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. It can also contain combinations of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when the hydrocarbyl residue is described as substituted, it may, optionally, contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue can also contain one or more carbonyl groups, amino groups, hydroxyl groups, or the like, or it can contain heteroatoms within the backbone of the hydrocarbyl residue. The term "alkyl" means 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" means a straight or branched chain, monovalent hydrocarbon group having at least one carbon-carbon double bond (e.g., ethenyl (-HC=CH<NUM>)). "Alkoxy" means an alkyl group that is linked via an oxygen (i.e., alkyl-O-), for example methoxy, ethoxy, and sec-butyloxy groups. "Alkylene" means a straight or branched chain, saturated, divalent aliphatic hydrocarbon group (e.g., methylene (-CH<NUM>-) or, propylene (-(CH<NUM>)<NUM>-)). "Cycloalkylene" means a divalent cyclic alkylene group, -CnH2n-x, wherein x is the number of hydrogens replaced by cyclization(s). "Cycloalkenyl" means a monovalent group having one or more rings and one or more carbon-carbon double bonds in the ring, wherein all ring members are carbon (e.g., cyclopentyl and cyclohexyl). "Aryl" means an aromatic hydrocarbon group containing the specified number of carbon atoms, such as phenyl, tropone, indanyl, or naphthyl. "Arylene" means a divalent aryl group. "Alkylarylene" means an arylene group substituted with an alkyl group. "Arylalkylene" means an alkylene group substituted with an aryl group (e.g., benzyl). The prefix "halo" means a group or compound including one more of a fluoro, chloro, bromo, or iodo substituent. A combination of different halo atoms (e.g., bromo and fluoro), or only chloro atoms can be present. The prefix "hetero" means that the compound or group includes at least one ring member that is a heteroatom (e.g., <NUM>, <NUM>, or <NUM> heteroatom(s)), wherein the heteroatom(s) is each independently N, O, S, Si, or P. "Substituted" means that the compound or group is substituted with at least one (e.g., <NUM>, <NUM>, <NUM>, or <NUM>) substituents that can each independently be a C<NUM>-<NUM> alkoxy, a C<NUM>-<NUM> haloalkoxy, a nitro (-NO<NUM>), a cyano (-CN), a C<NUM>-<NUM> alkyl sulfonyl (-S(=O)z-alkyl), a C<NUM>-<NUM> aryl sulfonyl (-S(=O)<NUM>-aryl), a thiol (-SH), a thiocyano (-SCN), a tosyl (CH<NUM>C<NUM>H<NUM>SO<NUM>-), a C<NUM>-<NUM> cycloalkyl, a C<NUM>-<NUM> alkenyl, a C<NUM>-<NUM> cycloalkenyl, a C<NUM>-<NUM> aryl, a C<NUM>-<NUM> arylalkylene, a C<NUM>-<NUM> heterocycloalkyl, and a C<NUM>-<NUM> heteroaryl instead of hydrogen, provided that the substituted atom's normal valence is not exceeded. The number of carbon atoms indicated in a group is exclusive of any substituents. For example - CH<NUM>CH<NUM>CN is a C<NUM> alkyl group substituted with a nitrile.

Claim 1:
A polycarbonate composition comprising:
<NUM> to <NUM> weight percent of a polycarbonate;
<NUM> to <NUM> weight percent of a polycarbonate-siloxane copolymer having a siloxane content of <NUM> to <NUM> weight percent, based on the total weight of the polycarbonate-siloxane copolymer;
<NUM> to <NUM> weight percent of a triazine-containing UV absorbing agent; and
<NUM> to <NUM> weight percent of a phosphazene flame retardant;
wherein weight percent of each component is based on the total weight of the composition.