MXPA01004021A - Polycarbonate resin/abs graft copolymer/san blends - Google Patents

Abstract

Thermoplastic resin blends containing an aromatic polycarbonate resin, an acrylonitrile-butadiene-styrene graft copolymer and a styreneacrylonitrile having a reduced styrene-acrylonitrile oligomer content exhibit an improved balance of flow properties and ductility.

Description

MIXES OF POLYCARBONATE RESIN. POLYMER OF GRAFTING OF ACRYLONITRILE-BUTADIENE-IS THREAD AND STYRENE- ACRYLONITRIL FIELD OF THE INVENTION The present invention relates to thermoplastic resin compositions, more specifically, to thermoplastic resin compositions containing polycarbonate resins ("PC"), an acrylonitrile-butadiene-styrene graft copolymer ("ABS") and a styrene copolymer -arylonitrile ("SAN").

BRIEF DESCRIPTION OF THE RELATED ART Polycarbonate resins are thermoplastics designed to be hard, rigid, with good impact resistance. However, the flow characteristics of polycarbonate resins sometimes cause difficulties in processing them. Various attempts have been made in the prior art to mix polycarbonate resins with other polymer modifiers to increase flow characteristics while maintaining the hardness and impact strength of the polycarbonate resin. For example, ABS graft copolymers have been blended with polycarbonate resins to produce a lower cost blend with improved processing characteristics, maintaining good impact strength (see US Patent No. 3,130,177, issued to Grabowski, and Plastics World, November 1977, pp. 5-58). However, many attempts to further improve the flow characteristics of the polycarbonate resin / ABS graft copolymer blends have resulted in a brittle material or a low undesirable heat deflection temperature ("HDT"). It is very desirable and useful to produce polycarbonate resin / ABS graft copolymer blends with good flow characteristics, because they have good low temperature ductility and high HDT.

BRIEF DESCRIPTION OF THE INVENTION -_ - In-a first aspect, the present invention- &s & amp; directs a uf-a thermoplastic resin composition comprising: a) a polycarbonate-aromatic resin; b) an acrylonitrile-butadiene-styrene graft copolymer; and c) a styrene-acrylonitrile copolymer with a reduced content of styrene-acrylonitrile oligomer. The resin composition of the present invention exhibits an improved balance of flow properties and ductility. In a second aspect, the present invention relates to a process for making a thermoplastic resin composition, which comprises mixing together, an aromatic polycarbonate resin, a acrylonitrile-butadiene-styrene graft copolymer and a styrene-acrylonitrile copolymer with reduced styrene-acrylonitrile oligomer content.

DETAILED DESCRIPTION OF THE INVENTION In a preferred embodiment, the thermoplastic resin composition of the present invention comprises, based on 100 parts by weight ("pep") of the thermoplastic resin composition, from 40 to 95 pep, more preferably from 50 to 90 pep, even more preferably from 55 to 80 pep, of the aromatic polycarbonate resin, from 3 to 58 pep, more preferably from 7 to 47 pep, still more preferably from 10 to 40 pep, graft copolymer of ABS and from 2 to 57 pep, more preferably from 3 to 43 pep, still more preferably from 5 to 35 pep, SAN.

Aromatic polycarbonate resin The aromatic polycarbonate resin component of the composition of the present invention comprises one or more aromatic polycarbonate resins. The aromatic polycarbonate resins suitable for use as the polycarbonate resin component of the thermoplastic resin composition of the present invention are known compounds whose preparation and properties have been described, see, ^ & ^ g ^ g ^ generally, US Patents Nos. 3,169,121; 4,487,896; and 5,411, 999, the descriptions of which are incorporated herein by reference. In a preferred embodiment, the aromatic polycarbonate resin component of the present invention is the reaction product of a dihydric phenol according to structural formula (I): HO-A-OH (I) wherein A is an aromatic radical divalent, with a carbonate precursor containing structural units according to formula (II): OR II - (O-A-O-C) - (ll) where A is as defined above. As used herein, the term "divalent aromatic radical" includes those divalent radicals containing a single aromatic ring such as phenylene, those divalent radicals containing a fused aromatic ring system such as, for example, naphthalene, those divalent radicals containing two or more aromatic rings joined by a non-aromatic linkage, such as for example, an alkylene, alkylidene or sulfonyl group, any of which may be substituted at one or more places in the aromatic ring with, for example, a group halo or an alkyl group of (C1-C6).

In a preferred embodiment, A is a divalent aromatic radical in accordance with formula (III): ## STR3 ## (lll) Suitable dihydric phenols include, for example, one or more of 2,2-bis- (4-hydroxyphenyl) propane ("bisphenol A"), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 4,4-bis (4-hydroxyphenyl) heptane, 3,5,3 ', 5'-tetrachloro-4,4'-dihydroxyphenyl) propane, 2,6-dihydroxynaphthalene, hydroquinone, 2, 4'-dihydroxyphenylsulfone. In a more preferred embodiment, the dihydric phenol is bisphenol A. The carbonate precursor is one or more of a carbonyl halide, a carbonate ester or a halogenoformate. Suitable carbonyl halides include, for example, carbonyl bromide and carbonyl chloride. Suitable carbonate esters include, for example, diphenyl carbonate, dichlorophenyl carbonate, dinaphthyl carbonate, phenyl tolyl carbonate and ditolyl carbonate. Suitable halogenoformates include, for example, bishalogenoformates of a dihydric phenol, such as, for example, hydroquinone, or glycols, such as, for example, ethylene glycol, neopentyl glycol. In a more preferred embodiment, the carbonate precursor is carbonyl chloride.

Suitable aromatic polycarbonate resins include linear aromatic polycarbonate resins and branched aromatic polycarbonate resins. Suitable linear aromatic polycarbonate resins include, for example, biphenol polycarbonate resin A. Suitable branched polycarbonates are known and are made by reacting a polyfunctional aromatic compound with a dihydric phenol and a carbonate precursor to form a branched polymer, see generally , U.S. Patent Nos. 3,544,514; 3,635,895; and 4,001, 184, the descriptions of which are incorporated herein by reference. The polyfunctional compounds are generally aromatic and contain at least three functional groups which are carboxyl, carboxylic anhydrides, phenols, halogenoformates and mixtures thereof, such as, for example, 1, 1, 1-di (4-hydroxyphenyl) ethane , 1, 3,5, - trihydroxy-benzene, trimellitic anhydride, trimellitic acid, trimellityl trichloride, 4-chloroformylphthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenotetracarboxylic acid, benzophen-tetracarboxylic dianhydride . Preferred polyfunctional aromatic compounds are 1, 1, 1 -tri (4-hydroxyphenyl) ethane, trimellitic anhydride or trimellitic acid or their halogenoformate derivatives. In a preferred embodiment, the polycarbonate resin component of the present invention is a linear polycarbonate resin derived from biphenol A and phosgene.

In a preferred embodiment, the weight average molecular weight of the polycarbonate resin is from about 10,000 to about 200,000 grams per mole ("g / mole"), and in another preferred embodiment, the weight average molecular weight of the resin of polycarbonate is from about 10,000 to about 100,000 grams per mole ("g / mole"), as determined by gel permeation chromatography in relation to polystyrene standards. Said resins typically have an intrinsic viscosity of from about 0.3 to about 1.5 deciliters per gram in methylene chloride at 25 ° C. Polycarbonate resins are made by known methods, such as, for example, interfacial polymerization, transesterification, solution polymerization or melt polymerization. The copolyester-carbonate resins are also suitable for use as the aromatic polycarbonate resin component of the present invention. The copolyester-carbonate resins suitable for use as the aromatic polycarbonate resin component of the thermoplastic resin composition of the present invention are known compounds whose preparation and properties have been described, see, generally, U.S. Pat. Nos. 3,169,121; 4,430,484; and 4,487,896, the descriptions of which are incorporated herein by reference. The copolyester-carbonate resins comprise linear or randomly branched polymers containing repeated carbonate groups, carboxylate groups and aromatic carbocyclic groups in the chain fe-fe, .. j-t ...- iAa of polymer, in which at least some of the carbonate groups are attached directly to the carbon atoms in the ring of the aromatic carbocyclic groups. In a preferred embodiment, the copolyester-carbonate resin component of the present invention is derived from a carbonate precursor, at least one dihydric phenol and at least one dicarboxylic acid or dicarboxylic acid equivalent. In a preferred embodiment, the dicarboxylic acid is one in accordance with formula (IV): O O II II HO-C-A'- C-OH (IV) wherein A 'is alkylene, alkylidene, cycloaliphatic or aromatic and is preferably an unsubstituted phenylene radical or a substituted phenylene radical which is substituted at one or more places on the aromatic ring, wherein each of the substituent groups is independently alkyl (C1-C6), and the copolyester-carbonate resin comprises a first structural unit according to the above formula (II) and a second structural unit according to the formula (V): O or II - (O-C-A'- C) - (V) where A 'is as defined above.

Suitable carbonate precursors and dihydric phenols are those described above. Suitable dicarboxylic acids include, for example, phthalic acid, isophthalic acid, terephthalic acid, dimethylterephthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, acetic acid, sebasic acid, acid dimethylmalonic, 1,2-dodecanoic acid, cis-1,4-cyclohexanedicarboxylic acid, trans-1,4-cyclohexanedicarboxylic acid, 4,4'-bisbenzoic acid, naphthalene-2,6-dicarboxylic acid. Suitable dicarboxylic acid equivalents include, for example, anhydride, ester or halide derivatives of the dicarboxylic acids described above, such as, for example, phthalic anhydride, dimethyl terephthalate, succinyl chloride. In a preferred embodiment, the dicarboxylic acid is an aromatic dicarboxylic acid, more preferably one or more of a terephthalic acid and isophthalic acid. In a preferred embodiment, the ratio of the ester linkages to the carbonate linkages present in the copolyester-carbonate resin is about 0.25 to 0.9 ester linkages per carbonate linkage. In a preferred embodiment, the copolyester-carbonate copolymer has a weight average molecular weight of from about 10,000 to about 200,000 g / moles.

The copolyester-carbonate resins are made by known methods, such as, for example, interfacial polymerization, transesterification, solution polymerization or melt polymerization.

ABS Graft Copolymer The ABS graft copolymer component of the composition of the present invention comprises one or more ABS graft copolymers. ABS graft copolymers suitable for use as the ABS graft copolymer component of the composition of the present invention are well known in the art. ABS graft copolymers are two-phase systems based on a continuous phase of styrene-acrylonitrile copolymer (SAN) and a dispersed elastomeric phase, typically based on butadiene rubber. Small amounts of styrene and acrylonitrile are grafted onto the rubber particles to make the two phases compatible. Three main processes that can be used to prepare ABS include emulsion, volume / mass polymerization and suspension or combinations thereof. ABS emulsion polymerization is a two-step process involving the polymerization of butadiene to form a rubber latex, followed by the addition and polymerization of acrylonitrile and styrene during which the rubber grafting and the production of rubber are carried out. the continuous phase of SAN. The rubber content of an ABS graft when made in emulsion can vary from about 10 to about 90% by weight and the SAN will graft from about 10 to 90% by weight of the ABS graft composition. The ratio of styrene to acrylonitrile ranges from 50:50 to 85:15. When it is made in emulsion, the rubber latex will have a particle size ranging from about 0.15 to about 0.5 microns in weight, preferably 0.3 microns. In composition, the rubber phase may be composed of polybutadiene, styrene-butadiene or copolymers of butadiene-acrylonitrile, polyisoprene, EPM (ethylene / propylene rubber), EPDM rubbers (ethylene / propylene / diene rubbers containing as diene, a non-conjugated diene such as hexadiene- (1, 5) or 0 norbornadiene in small amounts) and crosslinked acrylonitrile rubbers based on C 1 -C 8 acrylonitriles, in particular ethyl, butyl and ethylhexyl acrylate. One or more rubber-grafted resins of about 10 to 90 and about 90 to 10% by weight may also be used. The latex emulsion breaks down and the ABS is recovered at the end of the polymerization. In the volume process, the polymerization is carried out in styrene / acrylonitrile monomer instead of in water. Instead of making the rubber, a rubber produced before dissolves in the monomer solution. Subsequently, the rubber-monomer solution is fed into the reactors and grafting / polymerization is carried out. When it is produced by means of a volume or volume-suspension process, the soluble rubber will vary from about 5 to about 25% by weight and the dispersed rubber phase will have a diameter ranging from about 0.5 microns to approximately 10 microns. A large percentage by weight of the free SAN phase is present depending on the amount of rubber used. Instead of styrene and acrylonitrile monomers used in grafted or ungrafted resins, monomers such as alpha-methylstyrene, paramethylstyrene, mono-, di- or tri-halo-styrene, alkylmethacrylates, alkyl acrylates, maleic anhydride, methacrylonitrile, maleimide, N-alkylmaleimide, N-arylmaleimide or N-arylmaleimides substituted with alkyl or halogen can be replaced by the styrene or acrylonitrile or added thereto. Like the bulk process, the suspension polymerization uses rubber dissolved in the monomer solution, but after polymerizing SAN at lower conversions, the rubber / SAN / monomer mixture is suspended in water and the polymerization is completed.

SAN 15 Copolymer The SAN copolymer component of the composition of the present invention comprises one or more SAN copolymers. Conventional SAN copolymers comprise from about 0.1 to about 10% by weight of the oligomer content, wherein the oligomers can be generally defined as those components of the oligomer.

SANs that have a molecular weight of about 15,000 grams per mole or less. Typically the oligomers are defined as having a molecular weight of about 10,000 grams per mole or less. gi ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\ moles, more preferably 50,000 g / moles to about 90,000 g / moles, and even more preferably from about 60,000 g / moles to about 85,000 g / moles, where the molecular weights are measured by gel penetration chromatography related to standards of polystyrene with narrow dispersion capacity. The SAN copolymer typically comprises from about 10 to 40% by weight, preferably from 15 to 35% by weight, more preferably from 20 to 30% by weight of acrylonitrile, the remainder being styrene. It has been found that by removing at least some of the lower molecular weight end (i.e., at least some of the oligomer content) of the SAN distribution as originally polymerized, a ductile-brittle transition temperature is produced with reduced slotted Izod. (which indicates improved ductility). Additionally, the removal of at least part of the lower molecular weight end of the distribution results in a slight increase in the viscosity of the mixture. In this way, the resultant viscosity-ductility balance is very attractive. In addition, by selecting the amount of oligomers removed, it is possible to adjust the polycarbonate / ABS / SAN mixture to have an acceptable mix viscosity, resulting in a product with a wide variety of properties. The removal of the lower molecular weight end of the distribution also results in an increase in the Tv (and HDT) of the mixtures. This increase in Tv (and HDT) is not achieved simply by moving to a higher molecular weight SAN. The reduction of the content of the lower molecular weight materials, ie the styrene-acrylonitrile oligomers, in the styrene-acrylonitrile copolymer component of the composition of the present invention can be achieved by any suitable form. In a preferred embodiment, the oligomer content of the SAN copolymer component of the present invention is reduced by chemical fractionation. Suitable chemical fractionation techniques are well known in the art. In a preferred chemical fractionation technique, the SAN copolymer is dissolved in a first solvent, such as, for example, methyl ethyl ketone, wherein the high molecular weight SAN copolymer species and the lower molecular weight SAN oligomeric species are soluble and subsequently in a second solvent, such as, for example, sopropanol or methanol, wherein high molecular weight SAN copolymer species which are relatively insoluble, are added to the solution by mixing at a sufficiently low rate to avoid precipitation of the copolymer species of SAN of high molecular weight. Subsequently, the resulting mixture is separated into two layers, i.e., a layer of the first solvent and a layer of the second solvent, and the fractionated high molecular weight SAN copolymer species are isolated from the layer of the first solvent by the addition of more than the second solvent. Although a preferred method for removing the oligomer content is that of chemical fractionation, this should not be considered as limiting the present invention. Other methods can be used to remove the oligomer content and the present invention encompasses said methods. In addition, the oligomer content can be removed at any time. That is, the oligomers can be removed from the SAN component before mixing with the polycarbonate component, or the oligomers can be removed after mixing, or a combination of the removal of oligomers can also be used before mixing them and then mixing them.

Other components In addition, certain additives may be included in the resin composition of the present invention such as antistatic agents, fillers, pigments, colorants, antioxidants, heat stabilizers, ultraviolet light absorbers, lubricants, flame retardants and other commonly used additives. in polycarbonate / ABS / SAN blends. Suitable antistatic agents that can optionally be incorporated into the resin mixture of the present invention include, but are not limited to, the reaction products of the oxide block polymers. of polyethylene with epichlorohydrin, polyurethanes, polyamides, polyesters or polyetheresteramides. Suitable fillers that may optionally be incorporated into the resin blend of the present invention include, but are not limited to, talc, fiberglass, calcium carbonate, carbon fiber, clay, silica, mica and conductive metals, and the like. The mold release agents can optionally be incorporated into the resin mixture of the present invention. The products of the present invention can be made by combining and mixing the components of the composition of the present invention under conditions suitable for the formation of a mixture of the components, such as, for example, by melt mixing using, for example, a double roller mill, a Banbury mixer, or a twin screw or single screw extruder, and, optionally, subsequently reduce the composition thus formed, in particulate form for example, by granulating or grinding the composition. The mixtures of the present invention can be molded into articles having useful shapes by means of a variety of means such as injection molding, extrusion, rotary molding, blow molding and thermoforming to form articles such as, for example, computer housings and machines for offices, appliances for the home. Several demonstrations of the present invention are included in the examples presented below. However, the examples should be considered as illustrative and not as limiting the scope of the invention, as defined in the appended claims.

EXAMPLES The following abbreviations are used in the examples: PC-1: Linear polycarbonate resin having an absolute weight average molecular weight of about 29,000 g / moles; PC-2: Linear polycarbonate resin having an absolute weight average molecular weight of about 24.00 g / moles; ABS: An acrylonitrile-butadiene-styrene graft copolymer containing about 50% by weight of butadiene and 50% by weight of styrene-acrylonitrile copolymer (75% by weight of styrene and approximately 25% by weight of acrylonitrile); SAN-1: Copolymer of, 75% by weight of styrene and 25% by weight of acrylonitrile having a relative weight average molecular weight of about 62,600 g / mole; SAN-2: SAN-1 having about 3.5% by weight of the oligomer content removed by chemical fractionation and having a relative weight average molecular weight of about 66,600 g / moles; SAN-3: SAN-1 having about 7.0% by weight of the content of oligomer removed by chemical fractionation and having a relative weight average molecular weight of about 71,500 g / mol; and SAN-4: Copolymer of about 75% by weight of styrene and 25% by weight of acrylonitrile and having a relative weight average molecular weight of about 87,600 g / mole.

EXAMPLES 1 AND 2 AND COMPARATIVE EXAMPLES C1-C2 The mixtures of examples 1-2 of the present invention and the Comparative examples C1-C2 were each made by combining the components described below in the relative amounts (each expressed in parts by weight) which are set out in Table 1. The mixtures containing the ingredients named in Table 1 are they prepared by mixing the components in a Henshel mixer during About one minute, and then the mixture was added into the extruder hopper. In a typical small-scale laboratory experiment, a 20 mm Welding Engineers six-barrel extruder was used to combine these mixtures at 320-400 rpm with the melting temperature at approximately 287 ° C. The combined materials were injection molded in a Engel moulder from 28 tons to approximately 273 ° C. The test specimens had a thickness of 3.2 ± 0.2 mm, unless otherwise specified. The impact with slit Izod was measured in accordance with procedure D256 of the ASTM test. The data with Izod slotted on a temperature scale. The ductile / brittle temperatures were determined as the temperature at which the impact energy fell below 0.43 km-m / cm. The viscosity of the samples was measured using a Goettfert capillary rheometer. The viscosity was measured at about 287 ° C at frequencies ranging from about 100 to about 6300 Hz. The absolute weight average molecular weights of the polycarbonate resins were determined by gel permeation chromatography relative to the polycarbonate standards of Absolute molecular weight. SAN-1 and SAN-4 are conventional SAN degrees. SAN-2 was prepared by taking approximately 300 grams of a SAN-1 type SAN and dissolving it in approximately 1.5 liters of methyl ethyl ketone and approximately 2.1 liters of isopropanol were added dropwise while the solution was stirred. The addition of the isopropanol was maintained at a sufficiently slow rate to avoid precipitation of the polymer. The mixture was allowed to stand for about 1 hour. The top layer was decanted and concentrated to a drying state to give approximately 10.5 grams of residue. The polymer dissolved in the lower layer was precipitated after a slow addition of methanol in a mixer. The precipitate was filtered and dried in a vacuum oven overnight at about 40 ° C and subsequently at 80 ° C for several days.

SAN-3 prepared for the shot? approximately 250 grams of a SAN-1 type SAN and dissolve it in approximately 1.25 liters of methyl ethyl ketone and approximately 1.3 liters of isopropanol were added dropwise, as with the formation of SAN-2. The same procedure that was used to formulate SAN-3 was used to formulate SAN-2. The viscosity of the mixture, the results of the ductile / brittle transition temperature with slotted Izod, the phase Tv of the polycarbonate, and the HDT are set forth below in Table 1, for each of the compositions.

TABLE 1 C1 C2 PC-1 36.8 36.8 36.8 36.8 PC-2 27.7 27.7 27.7 27.7 SAN-1 22.0 SAN-2 22.0 SAN-3 22.0 SAN4 22.0 ABS 13 13 13 13 Antioxidants and flow improver 0.5 0.5 0.5 0.5 Properties Ductile / brittle transition temperature with slotted Izod (° C) -10 -38 -25 -35 Viscosity of the mixture (Pa-sec, measured at 100 sec-1) 209 293.1 226.6 257.9 Phase TV Pe (° C) 144.46 143.5 149.1 147.9 HDT (° C) 108 111 111 ? DT was not measured for C2 Examples 1 and 2 above and comparative examples C1 and C2 show that by removing at least some of the oligomer's distribution from the SAN component of a polycarbonate / ABS / SAN mixture, it is possible obtain a ductile / brittle transition temperature with Izod slotted while a relatively low mixing viscosity is maintained.

Since the above presentation includes a very particular description, various modifications to the description can be made by those skilled in the art and said modifications should be considered within the scope of the claims appended hereto.

Claims (11)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for making a thermoplastic resin composition comprising reducing the oligomer content of a styrene-acrylonitrile copolymer by chemical fractionation and mixing an aromatic polycarbonate resin, an acrylonitrile-butadiene-styrene graft copolymer and the styrene copolymer acrylonitrile having a reduced oligomer content, wherein said oligomer is a component of the styrene-acrylonitrile copolymer having a molecular weight of 15,000 grams per mole or less.

2. The process according to claim 1, further characterized in that styrene-acrylonitrile copolymer has a weight average molecular weight of about 40,000 grams per mole to about 110,000 grams per mole.

3. The process according to claim 2, further characterized in that the styrene-acrylonitrile copolymer has a weight average molecular weight of about 50,000 grams per mole at about 90,000 grams per mole.

4. The process according to claim 3, further characterized in that the styrene-acrylonitrile copolymer has a weight average molecular weight of about 60,000 grams per mole to about 85,000 grams per mole.

5. The process according to claim 1, further characterized in that the aromatic polycarbonate resin has a weight average molecular weight of about 10,000 grams per mole to about 200,000 grams per mole.

6. The process according to claim 5, further characterized in that the aromatic polycarbonate resin comprises two or more aromatic polycarbonate resins.

7. The process according to claim 5, further characterized in that the aromatic polycarbonate resin comprises an aromatic polycarbonate resin having a weight average molecular weight of about 29,000 grams per mole.

8. The process according to claim 5, further characterized in that the aromatic polycarbonate resin comprises an aromatic polycarbonate resin having a weight average molecular weight of about 24,000 grams per mole.

9. The process according to claim 1, further characterized in that the thermoplastic resin composition comprises, based on 100 parts by weight of the composition, from about 4 parts by weight to about 59 parts by weight of the acrylonitrile copolymer -butadiene-styrene. jHi i ^^^^^ ggg

10. The process according to claim 1, further characterized in that the thermoplastic resin composition comprises, based on 100 parts by weight of the composition, from about 5 parts by weight to about 46 parts by weight of the acrylonitrile-styrene copolymer.

11. The composition according to claim 10, further characterized in that the acrylonitrile-styrene copolymer comprises, based on the total weight of the copolymer, from about 10 weight percent to about 40 weight percent of the acrylonitrile and of about 60 weight percent to about 90 weight percent of the styrene.