阅读说明：本技术 聚碳酸酯组合物、制造方法和使用方法 (Polycarbonate compositions, methods of manufacture, and methods of use ) 是由 刘幸 山巍 牛亚明 那莹 周洪梅 拉胡尔·帕蒂尔 优素福·苏卢布 普贾·巴贾杰 赵炜 于 2018-08-16 设计创作，主要内容包括：一种聚碳酸酯组合物,包括：连续的聚碳酸酯相；分布在连续相中且包含核-壳硅酮-(甲基)丙烯酸酯抗冲改性剂的不连续的第一相区,该抗冲改性剂包含硅酮弹性体的核和(甲基)丙烯酸酯共聚物的壳,其中第一相区具有至少1.7的纵横比、优选为至少1.8；以及分布在连续相中且包含烯基芳族-烯烃嵌段共聚物抗冲改性剂的不连续的第二相区,其中第二相区具有至少3的纵横比、优选为至少4,和6400平方纳米或更小、更优选为5700平方纳米或更小的相区尺寸。任选地,该聚碳酸酯组合物包括：聚碳酸酯；不同于该聚碳酸酯的溴化聚碳酸酯；包含30至70wt％的硅氧烷嵌段的聚(碳酸酯-硅氧烷)；包括硅酮弹性体的核和(甲基)丙烯酸酯共聚物的壳的核-壳硅酮-(甲基)丙烯酸酯抗冲改性剂；以及烯基芳族-烯烃嵌段共聚物抗冲改性剂。(A polycarbonate composition comprising: a continuous polycarbonate phase; a discontinuous first phase region distributed in a continuous phase and comprising a core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer, wherein the first phase region has an aspect ratio of at least 1.7, preferably at least 1.8; and a discontinuous second phase region distributed in the continuous phase and comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second phase region has an aspect ratio of at least 3, preferably at least 4, and a phase region size of 6400 square nanometers or less, more preferably 5700 square nanometers or less. Optionally, the polycarbonate composition comprises: a polycarbonate; a brominated polycarbonate different from the polycarbonate; a poly (carbonate-siloxane) comprising 30 to 70 wt% siloxane blocks; a core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer; and an alkenyl aromatic-olefin block copolymer impact modifier.)

1. A polycarbonate composition comprising:

a continuous phase comprising a polycarbonate component;

a discontinuous first phase region distributed in the continuous phase and comprising a core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer, wherein the first phase region has an aspect ratio of at least 1.7, preferably at least 1.8; and

a discontinuous second-phase region distributed in the continuous phase and comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second-phase region has an aspect ratio of at least 3, preferably at least 4, and a phase region size of 6400 square nanometers or less, more preferably 5700 square nanometers or less;

each of which was determined by scanning transmission electron microscopy of the outer surface of the molded sample to within 10 microns of the outer surface.

2. The composition of claim 1, wherein

Molded samples of the composition showed no tracking after at least 50 drops of 0.1% aqueous ammonium chloride solution measured at 600V according to ASTM D-3638-85; and is

A molded sample of the composition having a thickness of 3.2 millimeters had at least one of the following properties:

a notched izod impact strength greater than 500 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256;

a notched izod impact strength greater than 600 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256; or

Notched Izod impact strength greater than 500 joules/meter and ductility of 100%, measured at a temperature of-40 ℃ according to ASTM D256.

3. The polycarbonate composition of claim 1 or 2, comprising:

60 to 80 wt% of a polycarbonate;

10 to 30 wt% of a brominated polycarbonate different from the polycarbonate;

0.5 to 5 wt% of a poly (carbonate-siloxane) comprising 30 to 70 wt% siloxane blocks;

1 to 10 wt% of the core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer; and

0.5 to 5 weight percent of the alkenyl aromatic-olefin block copolymer impact modifier;

wherein the weight percent of each component is based on the total weight of the composition, which totals 100 wt%.

4. The composition of any one or more of the preceding claims, further comprising 0.01 to 2 wt% of an anti-drip agent, preferably wherein the anti-drip agent is poly (tetrafluoroethylene) -encapsulated styrene-acrylonitrile.

5. The composition of any one or more of the preceding claims, comprising 2 to 3wt, based on the total weight of the composition, of an alkenyl aromatic-olefin block copolymer impact modifier, preferably wherein the alkenyl aromatic-olefin block copolymer is a styrene-ethylene/butylene-styrene block copolymer.

6. The composition according to any one or more of the preceding claims, having at least one of the following properties:

a molded sample of the composition retains a Mw of at least 90% after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity;

a molded sample of the composition retains a Mw of greater than 85% after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity;

a molded sample of the composition retains a Mw of greater than 75% after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity.

7. The composition according to any one or more of the preceding claims, having at least one of the following properties:

molded samples of the composition retain at least 80% notched izod impact strength after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, measured according to astm d256 at 23 ℃,

molded samples of the composition retain at least 90% notched izod impact strength after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, measured according to astm d256 at 23 ℃;

after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, a molded sample of the composition retains at least 65% notched izod impact strength, measured according to astm d256 at 23 ℃;

after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, a molded sample of the composition retains at least 90% notched izod impact strength, measured according to astm d256 at 23 ℃;

wherein a molded sample of the composition retains at least 50% notched Izod impact strength, measured at 23 ℃ according to ASTM D256, after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, or

Molded samples of the composition retain at least 75% notched izod impact strength after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, measured at 23 ℃ according to astm d 256.

8. The composition of any one or more of the preceding claims, wherein a molded sample of the composition having a thickness of 3.2 millimeters has at least one of the following properties:

a notched izod impact strength greater than 500 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256;

a notched izod impact strength greater than 600 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256; or

Notched Izod impact strength greater than 500 joules/meter and ductility of 100%, measured at a temperature of-40 ℃ according to ASTM D256.

9. The composition of any one or more of the preceding claims, wherein a molded sample of the composition having a thickness of 0.8 millimeters has a UL94 flame rating of V0.

10. The composition according to one or more of the preceding claims,

wherein the polycarbonate comprises a bisphenol a homopolycarbonate;

preferably wherein the polycarbonate comprises

A first bisphenol A homopolycarbonate having a weight average molecular weight of 21,000 to 23,000 daltons in an amount of 15 to 45 wt%, based on the total weight of the composition, and

a second bisphenol A homopolycarbonate having a weight average molecular weight of 29,900 to 31,000 daltons in an amount of 40 to 70 weight percent based on the total weight of the composition.

11. The composition according to any one or more of the preceding claims, wherein the core-shell silicone- (meth) acrylate elastomer is a dimethylsiloxane-methyl methacrylate copolymer having a particle size of 200 to 400 nanometers or a particle size of greater than 400 nanometers.

12. The composition of any one or more of the preceding claims, having a thickness of 3.2 millimeters, having at least one of

A notched Izod impact strength of greater than 500 joules/meter and a ductility of 100 percent measured at a temperature of-30 ℃ according to ASTM D256,

a notched Izod impact strength of greater than 600 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256,

a notched Izod impact strength of greater than 500 joules/meter and ductility of 100%, measured at a temperature of-40 ℃ according to ASTM D256, or

UL94 flame retardant rating of V0.

13. The composition of any one or more of the preceding claims, wherein the core-shell silicone- (meth) acrylate elastomer is a dimethylsiloxane-methyl methacrylate copolymer present in an amount of 1 to 5 wt% based on the total weight of the composition.

14. The composition according to any one or more of the preceding claims, comprising:

65 to 75 wt% of the polycarbonate, wherein the polycarbonate comprises a first bisphenol a homopolycarbonate having a weight average molecular weight of 21,000 to 23,000 daltons in an amount of 15 to 30 wt%, and a second bisphenol a homopolycarbonate having a weight average molecular weight of 29,900 to 31,000 daltons in an amount of 40 to 60 wt%;

15 to 25 weight percent of a brominated bisphenol a polycarbonate;

0.8 to 3 wt% of a poly (bisphenol a carbonate-dimethylsiloxane) comprising 30 to 70 wt% of a dimethylsiloxane block;

3 to 5 weight percent of a core-shell dimethylsiloxane-methyl methacrylate copolymer impact modifier;

1 to 5 weight percent of a styrene-ethylene/butylene-styrene block copolymer;

0.1 to 0.5 wt% of poly (tetrafluoroethylene) -encapsulated styrene-acrylonitrile; and

0.1 to 3 wt% of a combination of a colorant, a mold release agent, a heat stabilizer, and an ultraviolet light stabilizer.

15. The composition of claim 14, wherein

Molded samples of the composition showed no tracking after at least 50 drops of 0.1% aqueous ammonium chloride solution measured at 600V according to ASTM D-3638-85; and is

Wherein a molded sample of the composition having a thickness of 3.2 millimeters has a notched izod impact strength greater than 500 joules/meter and 100% ductility measured at a temperature of-30 ℃ according to ASTM D256;

a molded sample of the composition having a thickness of 3.2 millimeters has a tensile strength greater than or equal to 55 megapascals, determined according to ASTM D638;

a molded sample of the composition having a thickness of 3.2 millimeters has a tensile strength greater than or equal to 2 gigapascals as determined according to ASTM D638; and is

Molded samples of the composition having a thickness of 0.8 millimeters had a UL94 flame rating of V0.

16. The composition of any one or more of the preceding claims, wherein a molded sample of the composition exhibits no marking after at least 50 drops of 0.1% aqueous ammonium chloride, as measured by astm d-3638-85 at 600V.

17. The composition of any one or more of the preceding claims, wherein the brominated polycarbonate comprises brominated bisphenol-A having a bromine content of 24 to 27.5 wt%, relative to the total weight of the brominated polycarbonate, preferably wherein the brominated polycarbonate comprises brominated bisphenol-A polycarbonate units.

18. The composition of any one or more of the preceding claims, wherein the poly (carbonate-siloxane) is a poly (bisphenol a carbonate-dimethylsiloxane) elastomer, and

having carbonate blocks with a glass transition temperature of more than 70 ℃ and siloxane blocks with a glass transition temperature of-130 ℃ to-50 ℃,

a weight average molecular weight of 10,000 to 100,000 daltons;

a pre-yield elongation of at least 30% as measured by ASTM D638; and

a shore D hardness of 5 to 20 as measured by ASTM D2240.

19. An article comprising the composition of any one or more of the preceding claims, wherein

The article is a molded article, a thermoformed article, an extruded film, an extruded sheet, a multi-layer article of one or more layers, a substrate for a coated article, or a substrate for a metallic article,

preferably wherein the article is a solar device, an electrical junction box, an electrical connector, an electric vehicle charger, an outdoor electrical enclosure, a smart meter enclosure, a smart grid power node, a photovoltaic frame, or a miniature circuit breaker.

Background

The present disclosure relates to polycarbonate compositions having enhanced properties.

Polycarbonates are useful in a variety of applications, at least in part because they have a good balance of properties, such as moldability, heat resistance, impact resistance, and the like. Due to their wide use, particularly in the electrical and electronics industries, it is desirable to provide polycarbonate copolymer thermoplastic compositions having enhanced hydrolytic properties, good tracking resistance, flame retardant properties, and low temperature impact properties. Accordingly, there remains a need in the art for polycarbonate copolymer compositions having enhanced hydrolytic stability and low temperature impact properties. It would be a further advantage if the composition had good tracking resistance without significantly adversely affecting one or more of impact performance and flame retardant performance.

Disclosure of Invention

In one embodiment, a polycarbonate composition comprises: a continuous phase comprising a polycarbonate component; a discontinuous first phase region distributed in the continuous phase and comprising a core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer, wherein the first phase region has an aspect ratio of at least 1.7, preferably at least 1.8; and discontinuous second-phase regions distributed in the continuous phase and comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second-phase regions have an aspect ratio of at least 3, preferably at least 4, and a phase region size of 6400 square nanometers or less, more preferably 5700 square nanometers or less, each as determined by scanning transmission electron microscopy of the exterior surface of the molded sample, within 10 microns of the exterior surface.

In another embodiment, a polycarbonate composition comprises: 60 to 80 wt% of a polycarbonate; 10 to 30 weight percent of a brominated polycarbonate different from polycarbonate; 0.5 to 5 wt% of a poly (carbonate-siloxane) comprising 30 to 70 wt% siloxane blocks; 1 to 10 wt% of a core-shell silicone- (meth) acrylate impact modifier comprising a core of silicone elastomer and a shell of MMA copolymer; and 0.5 to 5 weight percent of an alkenyl aromatic-olefin block copolymer impact modifier; wherein the weight percent of each component is based on the total weight of the composition, which totals 100 wt%.

In another embodiment, an article comprises the above-described polycarbonate composition, wherein the article is a molded article, a thermoformed article, an extruded film, an extruded sheet, a multilayer article of one or more layers, a substrate for a coated article, or a substrate for a metallic article.

In yet another embodiment, a method of making an article comprises molding, extruding, casting, or shaping the above-described polycarbonate composition into an article.

Drawings

The above described and other features are exemplified by the following detailed drawings, description, examples, and claims.

Detailed Description

Provided herein are polycarbonate compositions comprising a continuous polycarbonate phase, and first and second continuous phase domains of a specified size. The first phase region comprises a first impact modifier, in particular a core-shell silicone- (meth) acrylate impact modifier comprising a core of a silicone elastomer and a shell of a (meth) acrylate copolymer; the second phase region comprises a second impact modifier, particularly an alkenyl aromatic-olefin block copolymer impact modifier. Compositions having this morphology can have excellent tracking resistance and good low temperature impact properties.

Further provided herein are polycarbonate compositions having an advantageous balance of improved low temperature impact properties and hydrolytic stability. The composition may further have good tracking resistance or flame retardancy, or both. These properties are unexpectedly obtained by compositions comprising polycarbonate, brominated polycarbonate other than polycarbonate, a poly (carbonate-siloxane) elastomer, a silicon-based impact modifier, and an alkenyl aromatic-olefin block copolymer impact modifier, which can significantly improve the tracking resistance of the polycarbonate composition. The results are surprising because other polycarbonate compositions do not meet the high end (1500 volt) application requirements with respect to tracking without significant loss in low temperature impact performance and flame retardancy.

Also provided herein are polycarbonate compositions having improved tracking resistance. Improved tracking resistance can be obtained without compromising low temperature impact performance, electrical performance properties, and flame retardancy. In one embodiment, the desired flow properties may further be obtained. These properties are unexpectedly obtained by a composition comprising a polycarbonate, a brominated polycarbonate, a poly (carbonate-siloxane) elastomer, a core-shell silicone- (meth) acrylate impact modifier, an alkenyl aromatic-olefin block copolymer impact modifier, and an anti-drip agent. In one embodiment, a composition comprising a polycarbonate, a brominated polycarbonate, a poly (carbonate-siloxane) elastomer, a silicon-based impact modifier, and an alkenyl aromatic-olefin block copolymer impact modifier may result in improved low temperature impact performance and/or flame retardancy. The results are surprising because other polycarbonate compositions do not meet the high end (1500 volt) application requirements with respect to tracking without significant loss in low temperature impact performance and flame retardancy.

As noted above, the polycarbonate composition comprises a polycarbonate component. The polycarbonate component may include polycarbonate and brominated polycarbonate other than polycarbonate, as well as poly (carbonate-siloxane).

As used herein, "polycarbonate" refers to a homopolymer or copolymer having repeating carbonate units of formula (1)

Wherein R is¹At least 60% of the total number of radicals being aromatic, or each R¹Containing at least one C_6-30An aromatic group. There may be different R¹A combination of groups. The carbonate units may be derived from a dihydroxy compound,for example aromatic dihydroxy compounds of the formula (2) or bisphenols of the formula (3)

Wherein in formula (2), each R^hIndependently of one another, a halogen atom, e.g. bromine, C_1-10Hydrocarbyl radicals, e.g. C_1-10Alkyl, halogen substituted C_1-10Alkyl radical, C_6-10Aryl, or halogen substituted C_6-10Aryl, and n is 0 to 4; in the formula (3), R^aAnd R^bEach independently is halogen, C_1-12Alkoxy or C_1-12Alkyl, and p and q are each independently integers from 0 to 4, such that when p or q is less than 4, the valency of each carbon of the ring is filled with hydrogen.

In the embodiments of formulae (2) and (3), R^aAnd R^bEach independently is C_1-3Alkyl or C_1-3Alkoxy, p and q are each independently 0 to 1, and X^aIs a single bond, -O-, -S (O) -, -S (O)₂-, -C (O) -, formula-C (R)^c)(R^d) C of (A-C)_1-11Alkylene, wherein R^cAnd R^dEach independently is hydrogen or C_1-10Alkyl radical, each R^hIndependently of one another are bromine, C_1-3Alkyl, halogen substituted C_1-3Alkyl, and n is 0 to 1.

In other embodiments of formulas (2) and (3), p and q are each 0, or p and q are each 1, and R is^aAnd R^bEach is C_1-3An alkyl group, preferably methyl, meta to the hydroxyl group on each arylene group; x^aIs a bridging group connecting two hydroxy-substituted aromatic groups, wherein each C₆The bridging group and the hydroxy substituent of the arylene group being in C₆Are para to each other on the arylene radical, and X^aC which may be substituted or unsubstituted_3-18A cycloalkylene group; formula-C (R)^c)(R^d) C of (A-C)_1-25Alkylene-in which R is^cAnd R^dEach independently is hydrogen, C_1-12Alkyl radical, C_1-12Cycloalkyl radical, C_7-12Arylalkylene radical, C_1-12Heteroalkyl or cyclic C_7-12A heteroaryl alkylene group; or formula-C (═ R)^e) A group of (a) wherein R^eIs divalent C_1-12A hydrocarbyl group.

Examples of the diphenol (2) 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, or 2,4,5, 6-tetrabromorecinol; catechol; hydroquinone; substituted hydroquinones such as 2-methylhydroquinone, 2-ethylhydroquinone, 2-propylhydroquinone, 2-butylhydroquinone, 2-tert-butylhydroquinone, 2-phenylhydroquinone, 2-cumylhydroquinone, 2,3,5, 6-tetramethylhydroquinone, 2,3,5, 6-tetra-tert-butylhydroquinone, 2,3,5, 6-tetrafluorohydroquinone or 2,3,5, 6-tetrabromohydroquinone. Combinations comprising different diphenol compounds may be used.

Examples of bisphenol (3) include, for example, those listed in WO 2013/175448A1 and WO 2014/072923A 1. Combinations comprising different bisphenol compounds may be used. Specific dihydroxy compounds include resorcinol, 2-bis (4-hydroxyphenyl) propane (bisphenol A or BPA), 3-bis (4-hydroxyphenyl) phthalimide, 2-phenyl-3, 3' -bis (4-hydroxyphenyl) phthalimide (also known as N-phenylphenolphthalein bisphenol, "PPPBP" or 3, 3-bis (4-hydroxyphenyl) -2-phenylisoindolin-1-one), 1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 1, 1-bis (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane (TMC bisphenol).

In a more preferred embodiment, the bisphenol polycarbonate is a bisphenol A polycarbonate homopolymer, also known as a bisphenol A homopolycarbonate, having repeating structural carbonate units of formula (1 a).

Such linear homopolymers containing bisphenol a carbonate units (BPA-PC) include those commercially available from SABIC under the trade name LEXAN; or branched cyanophenol-terminated bisphenol A homopolycarbonate prepared by interfacial polymerization, containing 3 mole% of 1,1, 1-tris (4-hydroxyphenyl) ethane (THPE) branching agent, commercially available from SABIC under the trade name LEXAN CFR.

Polycarbonates may be prepared by known processes such as interfacial polymerization and melt polymerization, and are described, for example, in WO 2013/175448a1 and WO 2014/072923a 1. Endcapping agents (also known as chain stoppers or chain terminators) can be included in the polymerization process to provide end groups, for example, monocyclic phenols such as phenol, p-cyanophenol, and C₁-C₂₂Alkyl-substituted phenols such as p-cumylphenol, resorcinol monobenzoate and p-and 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-cumyl phenyl chloroformate and toluene chloroformate. Combinations of different end groups may be used. Branched polycarbonate blocks can be prepared by adding branching agents during the polymerization, such as trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxy-phenyl-ethane, isatin-bisphenol, trisphenol TC (1,3, 5-tris ((p-hydroxyphenyl) isopropyl) benzene), trisphenol PA (4(4(1, 1-bis (p-hydroxyphenyl) -ethyl) α, α -dimethylbenzyl) phenol), 4-chloroformyl phthalic anhydride, trimesic acid and benzophenone tetracarboxylic acid. The branching agents may be added in an amount of 0.05 to 2.0 weight percent (wt%). Combinations comprising linear polycarbonates and branched polycarbonates may be used.

An end-capping agent may be included during the polymerization to provide an end group. The end-capping agent (and thus the end groups) is selected based on the desired properties of the polycarbonate. Examples of exemplary blocking agents are monocyclic phenols, such as phenol and C₁-C₂₂Alkyl-substituted phenols such as p-cumylphenol, resorcinol monobenzoate and p-and t-butylphenol, monoethers of diphenols such as p-methoxyphenol, and of C_8-9Alkyl-substituted phenols with branched alkyl substituents, 4-substituted-2-hydroxybenzophenones and derivatives thereof, aryl salicylates, monoesters of diphenols, e.g. resorcinol monobenzoate, 2- (2-hydroxyaryl) -benzeneBenzotriazole and its derivatives, 2- (2-hydroxyaryl) -1,3, 5-triazine and its derivatives, monocarboxylic acid chlorides such as benzoyl chloride, (C)₁-C₂₂Alkyl) substituted benzoyl chlorides, bromobenzoyl chlorides, cinnamoyl chlorides, and 4-dicarboximide benzoyl chlorides, polycyclic, monocarboxylic acid chlorides such as trimellitic anhydride chloride and naphthoyl chloride, functionalized chlorides of aliphatic monocarboxylic acids such as acryloyl chloride and methacryloyl chloride, and monochloroformates such as phenyl chloroformate, alkyl-substituted phenyl chloroformate, p-cumyl phenyl chloroformate, and methyl toluate. Combinations of different end groups may be used.

In one embodiment, the polycarbonate is a bisphenol a homopolycarbonate having a weight average molecular weight of 10,000 to 100,000 daltons (Da), or 15,000 to 50,000Da, or 17,000 to 35,000Da, as measured by Gel Permeation Chromatography (GPC), using a crosslinked styrene-divinylbenzene column and calibrated to a bisphenol a homopolycarbonate reference. GPC samples can be prepared at a concentration of 1mg/ml and eluted at a flow rate of 1.5 ml/min. More than one bisphenol a homopolycarbonate may be present. For example, the polycarbonate composition can comprise a first bisphenol a homopolycarbonate having a weight average molecular weight of 15,000 to 25,000Da or 17,000 to 23,000Da or 18,000 to 22,000Da, or 21,000 to 23,000Da, as measured by GPC using bisphenol a polycarbonate standards; and a second bisphenol a homopolycarbonate having a weight average molecular weight of 26,000 to 40,000Da, or 26,000 to 35,000Da, or 28,000 to 31,000Da, each measured by GPC using bisphenol a polycarbonate standards. The weight ratio of the first bisphenol a homopolycarbonate to the second bisphenol a homopolycarbonate may be from 10:1 to 1:10, or from 5:1 to 1:5, or from 3:1 to 1:3, or from 2:1 to 1: 2. In another embodiment, the polycarbonate comprises a first bisphenol A homopolycarbonate having a weight average molecular weight of 19,000 to 26,000Da, or 20,000 to 25,000, more preferably 21,000 to 23,000Da, and a second bisphenol A homopolycarbonate having a weight average molecular weight of 28,000 to 35,000Da, or 29,000 to 32,000Da, more preferably 29,000 to 31,000 Da. In any of the preceding embodiments, the first bisphenol a homopolycarbonate may be present in an amount of 15 to 45 wt%, or 15 to 35 wt%, or 15 to 25 wt%, based on the total weight of the composition, and the second bisphenol a homopolycarbonate may be present in an amount of 40 to 70 wt%, or 40 to 60 wt%, or 45 to 55 wt%, based on the total weight of the composition.

In one embodiment, the polycarbonate composition comprises 60 to 80 wt%, or 65 to 75 wt% of one or more bisphenol a homopolycarbonates, each based on the total weight of the polycarbonate composition, which total 100 wt%.

The composition may further comprise a brominated polycarbonate different from the polycarbonate. Combinations of different brominated polycarbonates may be used. The brominated polycarbonate can be an oligomer or polymer and can be derived from an aromatic dihydroxy compound of formula (2) wherein each R is^hIs bromine and n is 1 to 4; or a bisphenol of formula (3) wherein X^aAs defined for formula (3), p and q are each independently 0 to 4, provided that the sum of p and q is at least 1, and R^aIndependently at each occurrence is C_1-3Methyl, C_1-3Alkoxy or bromo, provided that at least one R is^aIs bromine. In one embodiment, a combination of two or more different brominated aromatic dihydroxy compounds may be used. Alternatively, the brominated polycarbonate may be derived from a combination of brominated and non-brominated aromatic dihydroxy compounds. If a non-brominated aromatic dihydroxy compound is used, any of the above bisphenols (3) may be used. In one embodiment, when a non-brominated aromatic dihydroxy compound is used, the non-brominated aromatic dihydroxy compound may be bisphenol A. If a combination of brominated and non-brominated aromatic dihydroxy compounds is used, it is preferred that the combination comprises at least 25 mole percent (mol%) of the brominated dihydroxy aromatic compound, more preferably at least 25 to 55 mol% of the brominated dihydric phenol, to produce the flame retardant brominated polycarbonate. Branched brominated polycarbonate oligomers may also be used, as may combinations of linear brominated polycarbonate oligomers and branched brominated polycarbonate oligomers. Combinations of different brominated copolycarbonate oligomers may be used. Suitable brominated polycarbonates are disclosed in Curry, U.S. Pat. No. 4,923,933, Orlando et al, U.S. Pat. No. 4,170,700, and Orlando et al, U.S. Pat. No. 3,929,908.

The brominated polycarbonate can have a bromine content of 10 to 50 wt%, preferably 15 to 40 wt%, or 20 to 30 wt%, 24 to 27.5 wt%, each based on the weight of the brominated polycarbonate. Optionally, the brominated polycarbonate may have a phenol or 2,4, 6-tribromophenol end cap. The brominated polycarbonate can have an intrinsic viscosity of 0.2 to 1.5 deciliters/gram, as measured in methylene chloride at 25 ℃. Within this range, the intrinsic viscosity may be 0.4 to 1 deciliter per gram. The Mw of the brominated polycarbonate may be 1,000 to 30,000Da, for example 1,000 to 18,000Da, or 2,000 to 15,000Da, or 3,000 to 12,000 Da; alternatively, 15,000 to 25,000Da, or 20,000 to 25,000 Da. The brominated polycarbonate may be branched or linear, or a combination of branched and linear brominated polycarbonates may be used.

In a preferred embodiment, the brominated aromatic dihydroxy compound may be 2, 2-bis (3, 5-dibromo-4-hydroxyphenyl) propane (2 ', 6, 6' -tetrabromo-4, 4 '-isopropylidenediphenol (TBBPA)), bis (3, 5-dibromo-4-hydroxyphenyl) methanone, or 2, 2', 6,6 '-tetramethyl-3, 3', 5,5 '-tetrabromo-4, 4' -biphenol; non-brominated aromatic dihydroxy compounds useful for copolymerization with brominated aromatic dihydroxy compounds include bisphenol A, bis (4-hydroxyphenyl) methane, 2-bis (4-hydroxy-3-methylphenyl) propane, 4-bis (4-hydroxyphenyl) heptane and (3,3 '-dichloro-4, 4' -dihydroxydiphenyl) methane. In another preferred embodiment, the brominated polycarbonate comprises brominated carbonate units derived from TBBPA and carbonate units derived from bisphenol a, and more preferably comprises 30 to 70 wt% TBBPA and 30 to 70 wt% bisphenol a, or 45 to 55 wt% TBBPA and 45 to 55 wt% bisphenol a.

The polycarbonate composition can comprise 10 to 30 wt%, or 15 to 25 wt% of the brominated polycarbonate, wherein the wt% is based on the total weight of the composition, which totals 100 wt%. The brominated polycarbonate can be used in an amount that contributes 2 to 20 wt% of bromine to the composition, based on the total weight of the composition.

The polycarbonate composition may further comprise a poly (carbonate-siloxane) copolymer comprising carbonate units and siloxane units. The carbonate units are derived from the aromatic dihydroxy compounds (2) and (3) as described in formulas (1) and (1a) above. In a particular embodiment, the carbonate units have formula (1 a). The composition further comprises a poly (carbonate-siloxane), also known in the art as a polycarbonate-polysiloxane copolymer or a poly (carbonate-siloxane) elastomer.

The siloxane units (also referred to as polysiloxane blocks) optionally have the formula (5)

Wherein each R is independently C_1-13A monovalent organic group. For example, R may be C_1-13Alkyl, C-C₁₃Alkoxy radical, C_2-13Alkenyl radical, C_2-13Alkenyloxy radical, C_3-6Cycloalkyl radical, C_3-6Cycloalkoxy, C_6-14Aryl radical, C_6-10Aryloxy radical, C_7-13Arylalkylene radical, C_7-13Arylalkyleneoxy group, C_7-13Alkylarylene or C_7-13An alkylarylene group. The foregoing groups may be fully or partially halogenated with one or more of fluorine, chlorine, bromine or iodine. In embodiments where a transparent poly (carbonate-siloxane) is desired, R is not substituted with a halogen. Combinations of the foregoing R groups may be used in the same poly (carbonate-siloxane).

In one embodiment, each R is independently C_1-3Alkyl radical, C_1-3Alkoxy radical, C_3-6Cycloalkyl radical, C_3-6Cycloalkoxy, C_6-14Aryl radical, C_6-10Aryloxy radical, C₇Arylalkylene radical, C₇Arylalkyleneoxy group, C₇Alkylarylene or C₇An alkylarylene group. In another embodiment, each R is independently methyl, trifluoromethyl or phenyl.

The value of E in formula (10) can vary widely depending upon such considerations as the type and relative amount of each component in the thermoplastic composition, the desired properties of the composition, and the like. Typically, E has an average value of 2 to 1,000, 2 to 500, 2 to 200, or 2 to 125, 5 to 80, or 10 to 70. In one embodiment, E has an average value of 10 to 80 or 10 to 40, and in yet another embodiment, E has an average value of 40 to 80, or 40 to 70. Where E has a lower value, e.g., less than 40, it may be desirable to use a relatively larger amount of poly (carbonate-siloxane) copolymer. Conversely, where E has a higher value, e.g., greater than 40, a relatively lower amount of poly (carbonate-siloxane) copolymer may be used. A combination of first and second (or more) poly (carbonate-siloxane) s may be used, where the average value of E of the first copolymer is less than the average value of E of the second copolymer.

Suitable siloxane units have been described, for example, in WO 2008/042500 a1, WO 2010/076680 a1 and WO 2016/174592 a 1. In one embodiment, the siloxane units have the formula (6)

Wherein E is as defined for formula (5); each R may be the same or different and is as defined in formula (5), and Ar may be the same or different and is substituted or unsubstituted C₆-C₃₀Arylene, wherein a bond is directly connected to an aromatic moiety. The Ar group in formula (6) may be derived from C₆-C₃₀The dihydroxyarylene compound is, for example, a dihydroxy compound of formula (2) or formula (3). Exemplary dihydroxy compounds are 1, 1-bis (4-hydroxyphenyl) methane, 1-bis (4-hydroxyphenyl) ethane, 2-bis (4-hydroxyphenyl) propane, 2-bis (4-hydroxyphenyl) butane, 2-bis (4-hydroxyphenyl) octane, 1-bis (4-hydroxyphenyl) propane, 1-bis (4-hydroxyphenyl) n-butane, 2-bis (4-hydroxy-1-methylphenyl) propane, 1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl sulfide), and 1, 1-bis (4-hydroxy-t-butylphenyl) propane, or combinations thereof.

Specific examples of the siloxane unit of formula (6) include those of formulae (6a) and (6 b).

Wherein E is as described in formula (5). In one embodiment, E has an average value of 10 to 80, or 10 to 40, and in another embodiment, E has an average value of 40 to 80, or 40 to 70.

In another embodiment, the siloxane units have the formula (7)

Wherein R and E are as described for formula (5), and each R⁵Independently is divalent C_1-30A hydrocarbylene group, and wherein the polymerized polysiloxane unit is the reaction residue of its corresponding dihydroxy compound. In one embodiment, the polydiorganosiloxane blocks have the formula (8):

wherein R and E are as defined for formula (5). R in the formula (8)⁶Is divalent C_2-8An aliphatic group. Each M in formula (7) may be the same or different and may be halogen, cyano, nitro, C_1-8Alkylthio radical, C_1-8Alkyl radical, C_1-8Alkoxy radical, C_2-8Alkenyl radical, C_2-8Alkenyloxy radical, C_3-8Cycloalkyl radical, C_3-8Cycloalkoxy, C_6-10Aryl radical, C_6-10Aryloxy radical, C_7-12Arylalkylene radical, C_7-12Aralkylenealkyleneoxy radical, C_7-12Alkylarylene or C_7-12An alkylaryleneoxy group, wherein each n is independently 0, 1, 2,3, or 4.

In one embodiment of formula (8), M is bromo or chloro, an alkyl group such as methyl, ethyl or propyl, an alkoxy group such as methoxy, ethoxy or propoxy, or an aryl group such as phenyl, chlorophenyl or tolyl; r⁶Is a dimethylene, trimethylene or tetramethylene group; and R is C_1-8Alkyl, haloalkyl such as trifluoropropyl, cyanoalkyl, or aryl such as phenyl, chlorophenyl or tolyl.

In another embodiment of formula (8), R is methyl, or a combination of methyl and trifluoropropyl, or a combination of methyl and phenyl. In yet another embodiment of formula (8), R is methyl, M is methoxy, n is 1, and R is⁶Is divalent C_1-3An aliphatic group. Preferred polydiorganosiloxane blocks have the formula

Or a combination thereof, wherein E has an average value of 10 to 100, preferably 20 to 60, more preferably 30 to 50, or 40 to 50.

In one embodiment, the poly (carbonate-siloxane) comprises carbonate units derived from bisphenol a, and repeating siloxane units (8a), (8b), (8c), or a combination thereof (preferably formula 7a), wherein E has an average value of E having an average value of 10 to 100, or 20 to 60, or 30 to 60, or 40 to 60. In one embodiment, the poly (carbonate-siloxane) comprises carbonate units derived from bisphenol a and repeating siloxane units of formula (8a) (8b) or (8c), wherein E has an average value of 10 to 100, or 20 to 60, or 30 to 50, or 40 to 50.

The poly (carbonate-siloxane) can have a siloxane content of 30 to 80 wt%, or 30 to 70 wt%, or 35 to 65 wt%, or 35 to 62 wt%, each based on the total weight of the poly (carbonate-siloxane). As used herein, the "siloxane content" of a poly (carbonate-siloxane) refers to the content of siloxane units based on the total weight of the poly (siloxane-carbonate). The poly (carbonate-siloxane) can have a weight average molecular weight of 26,000 to 45,000Da, or 30,000 to 43,000Da, or 35,000 to 40,000Da, as measured by gel permeation chromatography using a crosslinked styrene-divinylbenzene column at a sample concentration of 1mg/ml, and as calibrated using bisphenol a polycarbonate standards. In other embodiments, the poly (carbonate-siloxane) may have a weight average molecular weight of 10,000 to 100,000Da, or 50,000 to 100,000 Da. In some embodiments, good tracking resistance is obtained in the composition (e.g., where a molded sample of the composition exhibits no tracking after at least 50 drops of a 0.1% aqueous ammonium chloride solution, measured at 600V, as determined according to ASTM D-3638), wherein the poly (carbonate-siloxane) has less than 60 wt% siloxane blocks, e.g., 30 to 50 wt%, or 35 to 45 wt%, each based on the total weight of the poly (carbonate-siloxane).

In one embodiment, the poly (carbonate-siloxane) can have carbonate blocks with a glass transition temperature greater than 70 ℃, greater than 75 ℃, or greater than 80 ℃, and siloxane blocks with a glass transition temperature from-130 ℃ to-50 ℃, or from-130 ℃ to-100 ℃. In these embodiments, the poly (carbonate-siloxane) copolymer is an elastomer, which is known and described, for example, in US84666249 to Gallucci et al. In a preferred embodiment, the poly (carbonate-siloxane) elastomer can have a pre-yield elongation of at least 30% as measured by ASTM D638. In one embodiment, the poly (carbonate-siloxane) may have one or more of the following: a percent (%) light transmission of 70% or more, and a haze of 10% or less, when measured at a thickness of 1.0mm according to ASTM D1003; a yellowness index of 10 or less when measured according to ASTM D629; or a shore D hardness of 5 to 20 as measured by ASTM D2240. Preferred poly (carbonate-siloxane) elastomers comprise bisphenol a carbonate units and dimethylsiloxane units.

The polycarbonate composition can comprise 2 to 10 wt%, or 3 to 5 wt%, or 4 to 5 wt% of the poly (carbonate-siloxane) elastomer, based on the total weight of the composition, which total is 100 wt%.

The polycarbonate composition may further comprise at least two different impact modifiers, a core-shell silicone- (meth) acrylate impact modifier, and an alkenyl aromatic-olefin block copolymer impact modifier. Impact modifiers can generally have an elastomeric (i.e., rubbery) polymer core or matrix having a Tg of less than 10 ℃, or less than-10 ℃, or from-40 ℃ to-80 ℃, and a rigid polymer superstrate grafted to the elastomeric polymer matrix.

The core-shell-silicone- (meth) acrylate impact modifier may include a rubbery silicone core and a grafted rigid (meth) acrylate shell rigid shell. The silicone core may comprise dimethylsiloxane units. The (meth) acrylate monomer used to form the shell is typically a combination of monofunctional and copolymerizable multifunctional (meth) acrylate monomers. Examples of monofunctional (meth) acrylate monomers include branched or straight chain (C)_1-8Alkyl) (meth) acrylates and glycidyl (meth) acrylates, and examples of the copolymerizable polyfunctional monomer include allyl (meth) acrylate, ethylene glycol dimethacrylate and 1, 3-butylene glycol dimethacrylate. Preferred monomers are methacrylic acid C such as methyl methacrylate_1-6An alkyl ester. Other monomers may optionally be present in the silicone core or rigid shell, for example, styrene, alpha-methylstyrene, halogen or C_1-3Alkyl-substituted styrenes, acrylonitrile, methacrylonitrile, maleic acid, maleic anhydride, C_1-4Alkyl and phenyl N-substituted maleimides, divinyl benzene, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate and the like.

Methods for preparing core-shell silicone- (meth) acrylate impact modifiers are known in the art, as described, for example, in U.S. Pat. nos. 7,615,594, 4,888,388, and 4,963,619. The silicone (meth) acrylate impact modifier may be prepared by emulsion polymerization, wherein a silicone rubber monomer is reacted with a first graft chain monomer to form a silicone rubber latex, for example, in the presence of a surfactant such as dodecylbenzenesulfonic acid. Alternatively, cyclic siloxanes such as cyclooctamethyltetrasiloxane and tetraethoxyorthosilicate may be reacted with a first graft chain monomer such as (gamma-methacryloxypropyl) methyldimethoxysilane. The monofunctional (meth) acrylate monomer is then polymerized with the silicone rubber particles, optionally in the presence of a crosslinking monomer such as allyl methacrylate, in the presence of a free radical generating polymerization catalyst such as benzoyl peroxide. In one embodiment, the impact modifier is prepared by an emulsion polymerization process that is free of basic materials such as C_6-30Alkali metal salts of fatty acids such as sodium stearate, lithium stearate, sodium oleate, potassium oleate, etc., alkali metal carbonates, amines such as dodecyldimethylamine, dodecylamine, etc., and ammonium salts of amines. These materials are commonly used as surfactants in emulsion polymerization and can catalyze transesterification or degradation of polycarbonates. In contrast, ionic sulfate, sulfonate, or phosphate surfactants may be used to prepare impact modifiers, particularly the elastomeric substrates of impact modifiersAnd (4) partial. Useful surfactants include, for example, C_1-22Alkyl or C_7-25Alkyl aryl sulfonate, C_1-22Alkyl or C_7-25Alkyl aryl sulfates, C_1-22Alkyl or C_7-25An alkyl aryl phosphate, a substituted silicate, or a combination thereof. A specific surfactant is C_6-16Is preferably C_8-12An alkyl sulfonate. The emulsion polymerization process is described and disclosed in various patents and literature of Dow and General Electric Company, etc.

The core-shell silicone- (meth) acrylate impact modifier may have a rubber content of 30 to 90 wt%; and a silicone core content of 50 to 80 wt%, or 60 to 70 wt%, or 65 to 75 wt%. The silicone (meth) acrylate impact modifier may have an average particle size of 100 nanometers to 2 micrometers. In one embodiment, the particle size is from 200 to 400nm, or greater than 500 nm.

Specific core-shell silicone- (meth) acrylate impact modifiers that may be used include those commercially available, for example, from Mitsubishi Rayon Co.Ltd. under the tradenames METABLEN S-2001, METABLEN S-2100, METABLEN S-2200, and METABLEN S-2501.

The polycarbonate composition may comprise 1 to 10 wt% of the core-shell silicone- (meth) acrylate impact modifier, for example 1 to 5 wt%, or 3 to 5 wt%. In one embodiment, the polycarbonate composition comprises 4 to 10 wt% of the core-shell silicone- (meth) acrylate impact modifier, or 5 to 10 wt%, for example 5 to 6 wt%, wherein the wt% is based on the total weight of the composition, which totals 100 wt%.

The second impact modifier is an alkenyl aromatic-olefin block copolymer impact modifier. The elastomeric phase may be a high molecular weight elastomeric material derived from an olefin or a conjugated diene. The polymers formed from conjugated dienes may be fully or partially hydrogenated. Optionally other copolymerizable monomers, e.g. (meth) acrylic acid or C thereof, may be present_1-8An alkyl ester derivative. For example, the elastomeric phase may include conjugated diene rubbers such as polybutadiene and polyisoprene; copolymers of conjugated dienes with less than 50 wt.% of copolymerizable monomers, e.g.Monovinyl compounds such as styrene, acrylonitrile, n-butyl acrylate or ethyl acrylate; or olefin rubbers such as ethylene propylene copolymers (EPR) or ethylene-propylene-diene monomer rubbers (EPDM). The rigid phase may be formed from alkenyl aromatic monomers such as styrene and alpha-methylstyrene. Optionally, other monovinylic monomers such as acrylonitrile or (meth) acrylic acid or C thereof may be present_1-8Alkyl ester derivatives, such as methyl methacrylate.

Specific alkenyl aromatic-olefin block copolymer impact modifiers include styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), styrene-ethylene-butadiene-styrene (SEBS), ABS (acrylonitrile-butadiene-styrene), acrylonitrile-ethylene-propylene-diene-styrene (AES), styrene-isoprene-styrene (SIS), methyl methacrylate-butadiene-styrene (MBS), and styrene-acrylonitrile (SAN). Such impact modifiers include those commercially available, for example, from KRATON polymers under the trade names KRATON G and KRATON F series.

The polycarbonate composition may comprise 0.5 to 5 wt% of an alkenyl aromatic-olefin block copolymer impact modifier, preferably 1.5 to 5 wt% or 2 to 5 wt%, or 2 to 3 wt%, wherein the wt% are based on the total weight of the composition, which totals 100 wt%.

The polycarbonate composition may optionally further comprise an epoxy water stabilizer (hydrostabilizer). The aqueous epoxy stabilizer may have a molecular weight of 2,500 to 8,500Da, or 3,000 to 6,000 Da. The epoxy water stabilizer may have an Epoxy Equivalent Weight (EEW) of 180 to 2800g/mol, or 190 to 1400g/mol, or 200 to 700 g/mol. In one embodiment, the aqueous epoxy stabilizer may comprise styrene groups and acrylic groups, such as the aqueous epoxy stabilizers described in US 2013/0131255 and US 6,984,694, or may be available under the trade name JONCRYL (e.g., JONCRYL ADR 4368 (styrene-acrylate copolymer with epoxy functionality). other aqueous epoxy stabilizers include JONCRYL ADR 4300 (epoxidized soybean oil). the polycarbonate composition may comprise 0.5 to 5 wt% of an alkenyl aromatic-olefin block copolymer impact modifier, preferably 1.5 to 5 wt% or 2 to 5 wt%, or 2 to 3 wt%, wherein the wt% is based on the total weight of the composition, which together is 100 wt%.

In addition to the polycarbonate, brominated polycarbonate, poly (carbonate-siloxane) elastomer, and impact modifier, the polycarbonate composition may also include various additives commonly incorporated into polymer compositions of this type, provided that the additive(s) are selected so as not to significantly adversely affect the desired properties of the thermoplastic composition, particularly tracking resistance, flame retardant properties, and/or low temperature impact properties. These additives may be mixed at a suitable time during the mixing of the components used to form the composition. Additives include fillers, reinforcing agents, antioxidants, heat stabilizers, light stabilizers, Ultraviolet (UV) light stabilizers, plasticizers, lubricants, mold release agents, antistatic agents, colorants such as titanium dioxide, carbon black, and organic dyes, surface effect additives, radiation stabilizers, flame retardants, and anti-drip agents. Additives such as combinations of anti-drip agents, UV stabilizers and colorants may be used. Generally, the additives are used in effective amounts which are generally known. For example, the total amount of additives (other than any impact modifier, filler, or reinforcing agent) can be 0.01 to 5 wt%, based on the total weight of the polycarbonate composition. For example, the total amount of additives (other than any impact modifier) can be 0.01 to 5 wt%, based on the total weight of the polycarbonate composition.

The polycarbonate composition may optionally include a colorant composition comprising a pigment or dye additive. Useful pigments can include, for example, inorganic pigments such as metal oxides and mixed metal oxides, such as zinc oxide, titanium dioxide, or iron oxide; sulfides such as zinc sulfide and the like; an aluminate salt; sodium sulfosilicate sulfates, chromates; carbon black; zinc ferrite; ultramarine; organic pigments such as azo, diazo, quinacridone, perylene, naphthalene tetracarboxylic acid, flavanthrone, isoindolinone, tetrachloroisoindolinone, anthraquinone, enthrones, dioxazine, phthalocyanine and azo lakes; pigment red 101, pigment red 122, pigment red 149, pigment red 177, pigment red 179, pigment red 202, pigment violet 29, pigment blue 15, pigment blue 60, pigment green 7, pigment yellow 119, pigment yellow 147, pigment yellow 150, and pigment brown 24; or a combination thereof.

The composition can have any suitable color, including white, gray, light gray, black, and the like. Grey or black may show values of L lower than 80. The composition having a gray or black color can comprise an amount of carbon black greater than 0 and less than 3.0 wt%, or less than 1.5 wt%, each based on the total weight of the colorant composition. In one embodiment, molded samples formed from the composition having a thickness of 1mm have an average L value of 29 or less as measured by the CIE laboratory method, 10 degree observer, D65 illuminant, including specular component, measured in reflectance mode.

In one embodiment, the polycarbonate composition comprises up to 10 weight percent, based on the total weight of the composition, of titanium dioxide, carbon black, inorganic pigments, organic pigments, dyes, or combinations thereof. Alternatively, the polycarbonate composition comprises a colorant, such as a black colorant, preferably comprising 0.1 to 0.5 wt% carbon black, or 0.2 to 0.5 wt% carbon black, based on the total weight of the composition. The polycarbonate composition can comprise 0.1 to 0.5 wt% of the organic dye, for example 0.2 to 0.5 wt%, based on the total weight of the polycarbonate composition.

Combinations of other additives may be used, such as combinations of mold release agents, heat stabilizers, and light stabilizers. Generally, the additives are used in effective amounts which are generally known. In one embodiment, the composition comprises 0.01 to 0.5 wt% of a mold release agent, for example 0.01 to 0.2 wt%, or 0.01 to 0.1 wt% of a mold release agent, based on the total weight of the polycarbonate composition; 0.01 to 0.5 wt% of a heat stabilizer, for example 0.01 to 0.2 wt%, or 0.01 to 0.1 wt% of a heat stabilizer, based on the total weight of the polycarbonate composition; 0.01 to 0.5 wt%, for example 0.01 to 0.2 wt%, or 0.01 to 0.1 wt%, of a light stabilizer, based on the total weight of the polycarbonate composition.

The polycarbonate compositions can be made by various methods known in the art. For example, the powdered polycarbonate 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 through a hopper into the throat of a twin screw extruder. Alternatively, at least one component may be incorporated into the composition by adding it directly to the throat or downstream extruder through a side feeder, or by mixing into a masterbatch with the desired polymer and feeding into the extruder. The extruder is typically operated at a temperature above that required to cause the composition to flow. The extrudate can be immediately quenched in a water bath and pelletized. The pellets so prepared may be one-fourth inch long or less as desired. These pellets may be used for subsequent molding, shaping or forming.

As described above, polycarbonate compositions are formulated to have excellent physical properties, including excellent hydrolytic stability. Hydrolytic stability relates to the ability of a product to resist chemical decomposition by hydrolysis, e.g. to retain molecular weight or strength after prolonged exposure to water. For high end applications, such as at 1500 a voltage, good hydrolytic stability and tracking resistance without affecting impact and flame retardant properties is desirable. In one embodiment, the hydrolytic stability is comparable to or better than that of EXL9330P from SABIC.

Molded samples of the polycarbonate composition retain a Mw of at least 80%, preferably at least 85%, 90%, 95%, 97%, or 98% after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity. Molded samples of the polycarbonate composition retain a Mw of at least 60%, preferably at least 65%, 70%, 80%, or 85% after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity. Molded samples of the polycarbonate composition retain a Mw of at least 50%, preferably at least 55%, 60%, 65%, 70%, 75%, or 80%, after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity.

Molded samples of the polycarbonate composition retain at least 80%, preferably at least 85%, 90%, 95%, 97%, or 98% notched izod impact strength after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, as measured according to ASTM D256 at 23 ℃. Molded samples of the polycarbonate composition retain at least 60%, preferably at least 70%, 80%, 90%, or 95% notched izod impact strength after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity, as measured according to ASTM D256 at 23 ℃. Molded samples of the polycarbonate composition retain at least 55%, preferably at least 60%, 65%, 70%, 75%, 80%, or 85% notched izod impact strength after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity.

The polycarbonate compositions have excellent physical properties, including excellent tracking resistance. In one embodiment, the composition has a drop count for the electromark of greater than or equal to 50 drops, greater than or equal to 60 drops, greater than or equal to 70 drops, greater than or equal to 75 drops, or greater than or equal to 80 drops at 600 volts as determined according to ASTM D-3638-85.

Molded samples of the polycarbonate composition can have good low temperature impact properties. A molded sample of the polycarbonate composition having a thickness of 3.2 millimeters can have a notched izod impact strength (NII) strength of greater than 500 joules/meter, greater than 600 joules/meter, greater than 700 joules/meter, or greater than 800 joules/meter, measured at-30 ℃ according to ASTM D256. Molded samples of the polycarbonate composition may also have a ductility of 90 to 100%, or 90% to 100%, or 100%, each measured according to ASTM 256, measured at-30 ℃.

A molded sample of the polycarbonate composition having a thickness of 3.2 millimeters can have an NII strength of greater than 300 joules/meter, greater than 400 joules/meter, or greater than 500 joules/meter, measured at-40 ℃ according to ASTM D256. Molded samples of the polycarbonate composition can also have a ductility of 20 to 100%, or 50 to 100%, or 80 to 100%, each measured according to ASTM 256, measured at-40 ℃.

Without being bound by theory, it is believed that the surprising combination of good tracking resistance and good low temperature impact performance is due to the compatibility of the composition, as shown by its microstructure. As described in the examples, molded panels having the above CTI and low temperature impact properties may be a continuous phase comprising a polycarbonate component. Disposed in the polycarbonate phase are first and second phase regions comprising two different impact modifiers. Both impact modifiers have strong interfacial interactions or associations. Molded plaques of samples that failed CTI showed evidence of two phase regions aggregating. Thus, in one embodiment, a molded panel comprising the composition may have a first phase region comprising a core-shell silicone- (meth) acrylate impact modifier, wherein the first phase region has an aspect ratio of at least 1.7, preferably at least 1.8, each as determined by scanning transmission electron microscopy. Further, a molded panel comprising the composition may have a second phase region comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second phase region has an aspect ratio of at least 3, preferably at least 4, each as determined by scanning transmission electron microscopy. The second phase region may also have a phase region size of 6400 square nanometers or less, more preferably 5700 square nanometers or less, each as measured by Scanning Transmission Electron Microscopy (STEM). The measurements were made of the outer surface of a molded sample containing the composition, particularly the first 10 microns of the sample. In some embodiments, molded samples of the composition having the specified phase zone size exhibit no tracking after at least 50 drops of 0.1% aqueous ammonium chloride solution as determined by ASTM D-3638-85, measured at 600V; and a molded sample of the composition having a thickness of 3.2 millimeters had at least one of the following properties: a notched izod impact strength greater than 500 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256; a notched izod impact strength greater than 600 joules/meter and a ductility of 100% measured at a temperature of-30 ℃ according to ASTM D256; alternatively, the notched izod impact strength is greater than 500 joules/meter and the ductility is 100% as measured at a temperature of-40 ℃ according to ASTM D256.

Molded samples of polycarbonate compositions having a thickness of 0.8 millimeters may have a UL94 flame rating of V0.

In one embodiment, the thermoplastic composition comprises 60 to 80 weight percent of a polycarbonate; 10 to 30 weight percent of a brominated polycarbonate; 0.1 to 5 wt%, or 2 to 5 wt% of a poly (carbonate-siloxane) comprising 30 to 70 wt% of a siloxane block, wherein the siloxane block comprises an average of 40 to 60 mol% siloxane units; 1 to 10 wt% of a core-shell silicone- (meth) acrylate impact modifier comprising a core of silicone elastomer and a shell of MMA copolymer; and 2 to 3 weight percent of an alkenyl aromatic-olefin block copolymer impact modifier; wherein the wt% of each component is based on the total weight of the composition, which totals 100 wt%. In this embodiment, the composition may have enhanced hydrolytic stability and one or more of good low temperature impact performance, good tracking resistance, and/or flame retardancy.

In another embodiment, a thermoplastic composition comprises 65 to 75 wt% polycarbonate, wherein the polycarbonate comprises a first bisphenol a homopolycarbonate having a weight average molecular weight of 21,000 to 23,000Da in an amount of 15 to 30 wt%, and a second bisphenol a homopolycarbonate having a weight average molecular weight of 29,900 to 31,000Da in an amount of 40 to 60 wt%; 15 to 25 weight percent of a brominated bisphenol a polycarbonate; 0.1 to 5 wt%, or 2 to 5 wt% of a poly (bisphenol a carbonate-dimethylsiloxane) elastomer comprising 60 to 80 wt% of a dimethylsiloxane block; 3 to 5 weight percent of a core-shell dimethylsiloxane-methyl methacrylate copolymer impact modifier; 3 to 5 weight percent of a styrene-ethylene/butylene-styrene block copolymer; 0.1 to 0.5 wt% of poly (tetrafluoroethylene) -encapsulated styrene-acrylonitrile; and 0.1 to 3 wt% of a colorant, 0.1 to 1 wt% of an ultraviolet light stabilizer; 0.01 to 1 weight percent of poly (tetrafluoroethylene) -encapsulated styrene acrylonitrile, and 0.01 to 3 weight percent of a phosphite stabilizer. In this embodiment, the composition may have good hydrolytic properties, tracking resistance, low temperature impact resistance, and/or flame retardancy.

In another embodiment, a molded sample of the composition can retain at least 90% of the Mw after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; a Mw of greater than 85% can be maintained after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; greater than 75% Mw can be maintained after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; at least 80% of the notched izod impact strength measured according to ASTM D256 at 23 ℃ can be maintained after 336 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; at least 65% of the notched izod impact strength measured according to ASTM D256 at 23 ℃ can be maintained after 692 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; at least 50% of the notched izod impact strength measured according to ASTM D256 at 23 ℃ can be maintained after 1000 hours in a hydrolysis chamber at 85 ℃ and 85% relative humidity; no electrical marks were shown after at least 50 drops of 0.1% aqueous ammonium chloride solution measured at 600V according to ASTM D-3638; and has a UL94 flame rating of V0.

Also provided are shaped, formed, or molded articles comprising the polycarbonate compositions. In one embodiment, the article comprising the polycarbonate composition is a molded article, a thermoformed article, an extruded film, an extruded sheet, a multilayer article of one or more layers, a substrate for a coated article, or a substrate for a metallized article. The polycarbonate compositions can be molded into useful shaped articles by a variety of methods, such as injection molding, extrusion, rotational molding, blow molding, and thermoforming. In another embodiment, at least one of the following articles is included in or derived from a composition encompassed by the present disclosure: solar devices, electrical junction boxes, electrical connectors, electric vehicle chargers, outdoor electrical enclosures, smart meter enclosures, smart grid power nodes, PV (photovoltaic) frameworks, and Miniature Circuit Breaker (MCB) applications.

The disclosure is further illustrated by the following non-limiting examples.