EP0693095A1

EP0693095A1 - Low gloss polymer blend compositions

Info

Publication number: EP0693095A1
Application number: EP94913386A
Authority: EP
Inventors: Henricus J. M. Van Dijk; Sarada P. Namhata; Martin J. Guest
Original assignee: Dow Chemical Co
Current assignee: Dow Chemical Co
Priority date: 1993-04-08
Filing date: 1994-04-07
Publication date: 1996-01-24
Also published as: JPH08508783A; WO1994024210A1; KR960701953A; CA2159351A1

Abstract

Thermoplastic polymer blend compositions having low gloss in combination with improved processability and good physical properties comprise: a polycarbonate polymer; low levels of an epoxy-group-containing copolymer; at least one monovinylidene aromatic copolymer which is rubber-modified and produced via a mass process; at least one monovinylidene aromatic copolymer which is rubber-modified and produced via an emulsion process; and optionally additional monovinylidene aromatic copolymers.

Description

LOW GLOSS POLYMER BLEND COMPOSITIONS

The present invention relates to thermoplastic polymer blends, more specifically, it relates to blends containing a styreπic polymer and a polycarbonate Injection molding of many thermoplastic polymers and blends thereof give parts having a glossy appearance However, a range of applications can be identified for which a matte or low gloss surface is desirable Although surface finishing techniques are available for reducing the gloss of molded parts, these techniques can require a separate process, such as surface embossing or coating There is a continuing need for easily processable polymers which give low gloss molded parts and which additionally retain good physical and mechanical properties

Blends of aromatic carbonate polymers with other thermoplastics are known in the art Examples of polycarbonate blends with styrenic copolymers include those systems using acrylonitπle-butadiene-styrene (ABS) components produced either via mass or mass- -suspension techniques, such as described in U S Patent 4,624,986, or those produced via emulsion techniques, such as described in U S Patent 3, 130,177 U S Patent 4,526,926 discloses polycarbonate/ABS blends having large rubber particles wherein the ABS is prepared via a mass process, via an emulsion process or a combination of both These blend systems are noted for their good processing characteristics and balance of physical properties which include impact strength and high heat distortion

Epoxy functional polymers are one class of polymers known to act as matting agents, resulting in reduced gloss of parts molded from thermoplastic polymers and their blends EP 89,042-B1 describes polycarbonate/ABS compositions which additionally include an epoxy-functional olefin polymer and these are disclosed as having good weld line strength EP 249,998-A and EP 375,940-A describe compositions where epoxy functionality is incorporated via copolymeπzation in the production of the grafted rubbers, and these compositions are disclosed to give low gloss appearance in molded parts EP 375,941 -A2 describes polycarbonate/emulsion ABS compositions, including an epoxy modified styrenic copolymer, which compositions give low gloss, molded parts The preferred ABS polymers often contain high amounts of rubber

Unfortunately, the prior art systems which incorporate an epoxy functional copolymer either achieve reduced gloss at the expense of processability, or the gloss is not exceptionally reduced There is a continued need for thermoplastic blend systems which have low gloss characteristics, retain physical properties such as impact strength and heat resistance, and additionally have good processability

The present invention provides such thermoplastic polymer blend compositions having low gloss in combination with improved processability and good physical properties In particular, this invention covers blends comprising a polycarbonate polymer, at least one monovinylidene aromatic copolymer which is rubber-modified and produced via a mass process, at least one monovinylidene aromatic copolymer which is rubber-modified and produced via an emulsion process, low levels of an epoxy-group-containing copolymer, and optionally additional monovinylidene aromatic copolymers These compositions retain good low gloss characteristics, and show improved processability

The compositions of the invention are useful in the preparation of molded goods such as components in automobiles, business machines, and other consumer products

The thermoplastic polymer blend composition of this invention comprises (A) from 35 to 90 weight parts of an aromatic carbonate polymer; (B) from 10 to 65 weight parts of a combination of monovinylidene aromatic copolymers, including (B1 ) from 1 to 99 weight percent of a mass polymerized rubber-modified copolymer, (B2) from 1 to 99 weight percent of an emulsion polymerized rubber-modified copolymer; and (B3) from 0 to 98 percent of a monovinylidene aromatic copolymer; and (C) from 0 1 to 15 weight parts of an epoxy- -containing alkene copolymer The thermoplastic polymer blend composition of this invention preferably comprises: (A) from 40 to 85 weight parts of an aromatic carbonate polymer, (B) from 15 to 60 weight parts of a combination of monovinylidene aromatic copolymers, and (C) from 1 to 10 weight parts of an epoxy-containing alkene copolymer Preferably, component (B) comprises (B1) from 20 to 80 weight percent of a mass polymerized rubber-modified copolymer; (B2) 'from 80 to 20 weight percent of an emulsion polymerized, rubber-modified copolymer; and (B3) from 0 to 60 percent of a monovinylidene aromatic copolymer More preferably, the thermoplastic polymer blend composition of this invention comprises (A) from 45 to 75 weight parts of an aromatic carbonate polymer; (B) from 25 to 55 weight parts of a combination of monovinylidene aromatic copolymers, and (C) from 2 to 8 weight parts of an epoxy-containing alkene copolymer

The polycarbonate resins suitable for use as component (A) herein include aromatic polycarbonates which contain the repetitive carbonate group,

O

II

-o-c-o-

and which have a divalent aromatic radical attached to said carbonate group Preferably, the polycarbonate can be characterized as possessing recurring structural units of the following formula and structural isomers thereof:

(R')n (R")n

wherein A is a single bond or is a divalent aliphatic radical such as an alkylene or an alkylidene radical usually with 1 to 7 carbon atoms, or a cycloalkylene or cycloalky dene radical usually with 5 to 15 carbon atoms, with all including their aromatically and aliphatically substituted derivatives In other variations of the polycarbonate resin, A can also represent -0-, -S-, -CO-, -SO- or -Sθ2- In the indicated structural formula, R' and R" are substituents other than hydrogen such as, for example, halogen or a saturated or unsaturated monovalent aliphatic radical having usually 1 to 7 carbon atoms, and each n is independently from 0 to 4

Typical of the above-mentioned structural unit are those which result from the reaction of phosgene (or other carbonyl-providing species) with bιs-(hydroxyphenyl) alkanes, bιs-(hydroxyphenyl) cycloalkanes, bιs-(hydroxyphenyl) sulfides, bιs-(hydroxyphenyl) ethers, bis- (hydroxyphenyl) ketones, bιs-(hydroxyphenyl) sulfoxides, bιs-(hydroxyphenyl) sulfones, α,α'-bιs- (hydroxyphenyl) isopropyl benzene, bιs-(3,5-bromo-4-hydroxyphenyl) sulfone, bιs-(tetrabromo- 4-hydroxyphenyl) propane, bιs-(3,5,6-trι-chloro-2-hydroxyphenyl) methane, 2,2'-chloro-4,4'- -cy lohexylidene phenol, tetrachlorohydroquinone and chloroethylene phenol Further possible structural units are those which result from bιs-(3,5-methyl-4-hydroxyphenyl) propane, 4,4'-bιs-(4-hydroxy-phenylthιo) phenylsulfone and phenophthalein

It is understood, of course, that the carbonate polymer may be derived from two or more different hydric phenols or a copolymer of a hydric phenol with a glycol if a copolymer carbonate rather than a carbonate homopolymer is desired Also suitable for the practice of this invention are blends of any of the above carbonate polymers

Also included in the terms "polycarbonate" and "aromatic carbonate polymer" are the ester carbonate copolymers of the types described in U S Patents 3J69J 21 , 4,330,662 and 4,105,633 Typical comonomers are dicarboxy c acids such as, for example, terephthahc acid Additionally included in the scope of this invention are so-called "branched polycarbonates" which are made by using the above-described polyhydπc monomers in combination with a suitable branching agent, normally tn- or higher polyfunctional molecules

Suitable polyhydπc reactants for use in preparing various polycarbonate resins are also described in U S Patents 3,062,781 , 2,970,131 and in German Offenlegungsschπft Nos 1 ,570,703, 2,21 1 ,956 and 2,21 1 ,957 Polycarbonates and their production are well-known and are described in, for example, "The Encyclopedia of Polymer Science and Technology," Vol 10, pp 710-764 (1969)

The polycarbonate resins employed herein preferably have a melt flow rate, measured according to ASTM D-1238 (condition O 300°C, 1 2 kg load), of from 0 5 to 200 g/10 mm, preferably from 2 5 to 100 g/10 minutes, more preferably from 5 to 90 g/10 minutes and especially preferred from 8 to 75 g/10 minutes

Component (B) comprises a combination of monovinylidene aromatic copolymers which are rubber-modified (B1 and B2) and optionally a non-rubber-modified monovinylidene aromatic copolymer (B3) For all described components (B1 , B2 and B3), suitable monovinylidene aromatic monomer constituents include styrene, alkyl-substituted styrenes such as alpha-alkylstyrene (for example, alpha-methylstyrene and alpha-ethylstyrene), various ring-substituted styrenes such as para-methylstyrene, ortho-ethylstyrene and 2,4-dιmethylstyrene, and ring-substituted halo-styrenes such as chloro-styrene and 2,4-dιchloro-styrene Styrene is the preferred monovinylidene aromatic monomer The monovinylidene aromatic monomer (especially styrene) typically constitutes from 55 to 99 weight percent of said monovinylidene aromatic copolymer and preferably constitutes from 60 to 95 (more preferably from 65 to 90) weight percent thereof Such monovinylidene aromatic copolymers are normally solid, hard (that is, non-elastomeπc) materials having a glass transition temperature in excess of 25°C Mixtures of these monomers can be employed Suitable relatively polar comonomers for use as the minor constituent in (that is, constituting from 1 to 45 weight percent of) the indicated monovinylidene aromatic copolymers include ethylenically unsaturated nitπles such as acrylonitπle, methacrylonitπle, ethacrylonitπle, ethylenically unsaturated anhydrides such as maleic anhydride, ethylenically unsaturated amides such as acrylamide, methacrylamide, esters (especially lower, for example, Ci-Cε, alkyl esters) of ethylenically unsaturated carboxy c acids such as methyl methacrylate, ethylacrylate, hydroxyethylacrylate, n-butyl acrylate or methacrylate, 2-ethyl-hexylacrylate, ethylenically unsaturated dicarboxyhc acid imides such as N-alkyl or N-aryl maleimides such as N-phenyl maleimide Especially preferred for use as the relative polar comonomer ingredient herein are the aforementioned ethylenically unsaturated nitπles Preferably, these relatively polar comonomers or mixtures thereof constitute from 5 to 40 weight percent of the indicated monovinylidene aromatic copolymer, and most preferably 10 to 35 weight percent

The polymer blend compositions have two or more components (for example, B 1 and B2) wherein the monovinylidene aromatic copolymers are rubber-modified, for example, having dispersed particles of a rubbery polymer with a glass transition temperature of 0°C or lower Especially preferred rubbery polymers for use herein are those having a glass transition temperature of -20°C or lower Examples of suitable such rubbery polymers include homopolymers of 1 ,3-conjugated alkadiene monomers, copolymers of from 60 to 99 weight percent of said 1 ,3-conjugated alkadienes with from 1 to 40 weight percent of a monoethylenically unsaturated monomer such as, for example, monovinylidene aromatic monomers (for example, styrene) and ethylenically unsaturated nitπles such as acrylonitrile and methacrylonitπle, ethylene/propylene copolymer rubbers, and ethylene/propylene/non- conjugated diene copolymers Especially preferred rubbery polymers for use herein include polymers composed of from 60 to 100 weight percent of 1 ,3-butadιene and from 0 to 40 weight percent of styrene or acrylonitrile

Rubber-modified copolymers, such as ABS, consist of a rigid matrix or continuous phase having dispersed therein particles of the elastomer, such particles usually having grafted thereto amounts of the rigid copolymer Component (B1) includes rubber-modified monovinylidene aromatic copolymers produced via mass or mass-suspension techniques, resulting in grafted rubber particles which have a portion of the rigid copolymer occluded in the rubber phase The rubber types described above are present in an amount of from 1 to 40 percent, preferably 3 to 25 percent, and most preferably 5 to 20 percent The rubber particles generally have a volume average particle size of from 0 4 to 10 micron Mass or bulk polymerized rubber-modified monovinylidene aromatic copolymers are commercially available and are known to those skilled in the art. See, for example, U S. Patents 3,243,481 ; 3,509,237; 3,660,535, 4,221 ,833 and 4,239,863

Component (B2) includes rubber-modified monovinylidene aromatic copolymers in which the rubber particles are produced via emulsion techniques At least a portion of the rubber particles are grafted to the matrix copolymer The rubber types described above advantageously are present in amounts of from 10 to 85 percent, preferably from 20 to 75 percent, and more preferably from 35 to 60 percent The rubber particles generally have a volume average particle size of from 0 05 to 5 micron Under most circumstances, emulsion polymerization techniques are generally economically feasible for the production of rubber particles having diameters less than about 0.25 μm Such particles must usually be agglomerated or coagulated in some way before, during and/or after grafting in order to achieve rubber particles having diameters greater than about 0.5 μm Agglomerating and coagulating techniques are well known in the art See, for example, U S Patents 3, 551 ,370, 3,666,704; 3,956,218 and 3,825,621 A particularly desirable technique for the controlled agglomeration of the particles of an emulsion-prepared rubber in an aqueous dispersion is taught in U.S Patent 4,419,496

Emulsion polymerized monovinylidene aromatic copolymers are commercially available, and preferably are in the form of butadiene rubber particles grafted with a mixture of styrene and acrylonitrile (SAN), and having a relatively high (greater than 20 percent) rubber content These rubber-reinforced copolymers can be prepared using techniques known to those skilled in the art and including, for example, the method taught in U S Patent 3J 30,177 Alternatively, the rubber particles, which advantageously can be butadiene or acrylate based rubbers, can be grafted with a mixture of styrene and/or (methyl meth)acrylate monomers. Examples of materials with this type of grafted rubber particle include the PARALOID^® series of products available from Rohm and Haas. The epoxy group-containing alkene copolymer, component (C), is a copolymer of at least one unsaturated epoxy compound and at least one alkene with or without at least one ethylenically unsaturated compound. While no special limitation is present in the composition of these monomers, the content of the unsaturated epoxy compound(s) is preferred to be from 0.05 to 95 percent by weight. As the unsaturated epoxy compound(s), there may be used the ones having an unsaturated group copolymerizable with an olefin and ethylenically unsaturated compound as well as an epoxy group in the molecule. For instance, unsaturated glycidyl esters, unsaturated glycidyl ethers, epoxyalkenes or p-glycidylstyrenes are usable. Those of the following formulas are also usable:

O

II

-R -C-O- CH2 _ CH - CH₂

\

-R -X - CH₂CH — CH₂ \ /

z I

-R -C- CH₂

\ / O wherein R is a C₂-Cιs hydrocarbon group having ethylenic unsaturation, Z is a hydrogen atom or a methyl group and X is:

More specifically, the following compounds are exemplified: glycidyl acrylate, glycidyl methacrylate, glycidyl itaconate, butenecarboxylates, allyl glycidyl ether, 2-methylallyl glycidyl ether, styrene-p-glycidyl ether 3,4-epoxybutene, 3,4-epoxy-3-methyl-1 -butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3-methylpentene, 5,6-epoxy-1-hexene, vinylcyclohexene monoxide and p-glycidylstyrene Mixtures of unsaturated epoxy compounds can be employed

Examples of the alkene include olef ins such asJor example, ethylene, propylene, butene-1 , pentene-1 , and 4-methylpentene-1 , and alkenyl aromatic compounds including the monovinylidene aromatic monomers mentioned hereinabove Preferred alkenes include ethylene and styrene Mixtures of alkenes can be employed

As the ethylenically unsaturated compound(s), there are exemplified olefins, vinyl esters having a C₂-Cβ saturated carboxy c acid moiety, acrylic and methacrylic esters having a C--Cg saturated alcohol moiety, maleic esters having a Ci- s saturated alcohol moiety, vinyl hahdes, vinyl ethers, N-vinyllactams and carbonamides Examples of preferred ethylenically unsaturated compounds include vinyl acetate and methyl acrylate These ethylenically unsaturated compounds may be copolymeπzed with the unsaturated epoxy compounds and the olefins in an amount of not more than 50 percent by weight, especially from 0 1 to 45 percent by weight based on the total weight of the monomers to be copolymeπzed Mixtures of ethylenically unsaturated compounds can be employed

The epoxy group-containing alkene copolymer (C) may be prepared by various procedures, of which one typical example comprises contacting an unsaturated epoxy compound and an alkene, with or without an ethylenically unsaturated compound, with a radical generating agent at a temperature of 40°C to 300°C under a pressure of 50 to 4000 atm Another typical example comprises irradiating gamma-rays into a mixture of poly-propylene with an unsaturated epoxy compound under a high degree of reduced pressure Typical methods of preparation are taught in U S Patent 4,721 ,761

Component (C) is used in amounts of from 0 1 to 15 parts by weight of the blend composition, preferably from 1 to 10 parts by weight and most preferably from 2 to 8 parts by weight Greater amounts of component (C) are found to adversely affect the blend properties, especially heat resistance

The blends of the invention may be further modified by the addition of other types of conventional additives known in the art of plastics compounding Such additives can include fillers (such as clay or talc), reinforcing agents (such as glass fibers), impact modifiers, other resins, plasticizers, flow promoters and other processing aids, stabilizers, colorants, mold release agents, flame retardants and ultraviolet screening agents

The compositions of the invention advantageously contain from 1 to 40 percent by weight of rubber, preferably from 2 to 30 percent by weight and most preferably from 3 to 25 percent by weight The compositions of the invention are prepared via any of the blending operations known for the blending of thermoplastics, such as solvent blending or blending in a kneading machine, such as a Banbury mixer, or an extruder. The sequence of addition is not critical but all main components should be thoroughly blended together.

When the components of the invention are combined as described hereinabove, a polymer blend having a surprising combination of low gloss and good processability is obtained. Further, the described blend compositions also retain other attributes such as good thermal properties and mechanical properties which include good toughness.

The following examples and comparative experiments are presented for purposes of illustration rather than for limitation. All parts and percentages are by weight unless otherwise indicated. The blend compositions of the Examples and Comparative Experiments are prepared by compounding the various components together. The blends are injection molded to prepare parts for the property evaluations. A Buss Ko-Kneader compounding machine, model MDK-46, is used to prepare the blends under the following conditions: the temperature profile is 160°C - 240°C - 250°C - 240°C - 160°C; the dosing speed is 30 rpm; and the throughput is 20 kg/hour at 204 rpm. Molding of blends is carried out on a Klockner Ferromatic KF-60 machine to produce plaques and other test parts under the following conditions: the temperature profile is 250°C - 255°C - 260°C - 270°C; the mold temperature is 75°C; the injection speed is 30 mm/s; and the cooling time is 30 s. All formulations include a colorant system which is 1.7 parts by weight of a carbon black, Taxa 2319, unless otherwise indicated. Other materials employed are as follows:

ABS-M is a mass polymerized ABS containing 15 percent acrylonitrile and 12 percent polybutadiene;

Calibre^® polycarbonate resins are products of The Dow Chemical Company;

Magnum^® 3453 and 3154 are commercially available mass ABS polymers produced by The Dow Chemical Company;

Magnum^® 3416HH is a high heat ABS available from The Dow Chemical Company;

Dylark^® 232 is a rubber modified styrene/maleic anhydride copolymer produced by The Atlantic Richfield Company;

Igetabond^® 2B is a product of The Sumitomo Chemical Company;

ABS-E is an emulsion polymerized SAN grafted polybutadiene with a 48 percent rubber content;

Tyril® styrene acrylonitrile resins are a product of The Dow Chemical Company; ^and

Paraloid^® 2B is a product of Rohm and Haas.

The properties reported below are measured according to the following methods: Melt Flow Rate (MFR) ISO 1 133 - 1981 Gloss, 60° ISO 2813 - 1978

Izod impact ISO 180 - 1982

Heat Distortion Temperature (HDT) ASTM D648 - 1988

Tensile Yield ISO R527 - 1966

Vicat ISO 306-1974 (method A; 50°C/hr, 5 kg load)

Example 1 and Comparative Experiment (C.E.) A

The compositions, given in weight parts, and relevant property data are as follows:

Example 1 C.E. A

COMPONENT (A) Calibre^® 300-10 61.8 61.8

COMPONENT (B1 ) ABS-M 14.3

COMPONENT (B2) ABS-E 7.55 15.1

COMPONENT (B2) Paraloid® 3607 1.5 -

COMPONENT (B3) Tyril^® 1 14 8.2 16.4

COMPONENT (C) Igetabond^® 2B 5.0 5.0

MFR 260°C/5 kg 6.0 2.9 (g/10 mi n) Gloss 60° (%) 28 24 lzod @ 23°C (kJ/m2⁾ 50 41

HDT (1.82 M Pa) (°C) 96 98

Tensile Yield (MPa) 45.8 45.3

Example 1 shows that the desired low gloss property is achieved while keeping a formulation of significantly higher flow performance than Comparative Experiment A as measured via the melt flow rate. The other thermal and mechanical properties of the blend Example 1 are improved or essentially maintained compared to that of Comparative Experiment A.

Examples 2-10 and Comparative Experiments B-F

The compositions, given in weight parts, and relevant property data are presented in Table 1.

Examples 2-7 illustrate a range of relevant composition ratios and different Component (A) types, including Example 5, which is based on a branched polycarbonate. Comparative Experiments B and E without Component (C) exhibit high gloss. Comparative Experiment C shows that addition of Component (C) to a formulation based only on mass ABS shows no significant gloss reduction. Comparative Experiment D is a formulation which only includes emulsion ABS as a component, and shows low gloss in combination with a major decrease in flow behavior.

Examples 8-10 illustrate the broad applicability of a range of different comonomers in combination with monovinylidene aromatic monomers, which are optionally rubber-modified, and comprise Component (B).

Comparative Experiment F shows that poor gloss and flow is observed for compositions low in Component (A).

The good thermal and impact properties associated with polycarbonate/ABS blends are maintained in the compositions of this invention.

Table 1 - Compo sitions and Properties

Example/C.E. 2 3 4 5 6 7 8 9 10 B* C* D* E* F*

Calibre^®300-10 ⁺ 62.5 - - 50.0 75.0 62.5 62.5 62.5 64.5 62.5 62.5 64.5 -

Calibre^® 300-4 ⁺ - 62.5 - - 30.0

Calibre^® 300-22 ⁺ 62.5

Calibre^® 603-3 ⁺ 62.5

Magnum^®3¹l53^0t 15.3 15.3 15.3 15.3 20.0 10.3 - - - 33.8 32.8 - - -

Magnum^®315ⁱT 15.3 10.3 - - - - -

Magnum^®3^l» 16HH! - 10.0 - - - - -

Dylark^®232" - - 15.3 - - - -

ABS-E¹ 10.0 10.0 10.0 10.0 13.3 10.0 10.0 12.5 10.0 - - 18.7 19.3 20.0

Tyril^® 114^# 7.5 7.5 7.5 7.5 10.0 - 7.5 - 7.5 - - 14J 14.5 15.3 lgetabond^®2B^@ 3.0 3.0 3.0 3.0 6.0 3.0 3.0 3.0 3.0 - 3.0 3.0 - 3.0

MFI 26075kg 4.4 2.63 8.87 2.96 2.23 4.21 5.60 7.59 6J7 18.9 14.8 2.93 9.45 1.38

Gloss 45.3 26.6 42.5 45.0 40.5 51.6 50.9 47.3 68.2 91.2 89.2 49.7 96.4 71.2

Vicat 130.3 133.3 127.7 126.8 115.6 141.5 129.8 132.7 128.5 128 123.3 129.7 129J 105

Izod 54.4 63.2 45.4 47.5 43.9 58.4 48.0 47.8 40.0 42.3 69.4 47.8 45.7 47.5

not an embodiment of the invention

+ Component (A) o Component (B1)

! Component (B)

$ Component (B2) # Component (B3)

@ Component (C)

Claims

CLAIMS:

1. A low gloss thermoplastic blend composition with improved flow characteristics comprising:

(A) from 35 to 90 parts by weight of an aromatic carbonate polymer;

(B) from 10 to 65 parts by weight of a combination of monovinylidene aromatic copolymers, the combination comprising:

(B 1) from 1 to 99 weight percent of a mass polymerized rubber-modified copolymer;

(B2) from 1 to 99 weight percent of an emulsion polymerized, rubber-modified copolymer;

(B3) from 0 to 98 weight percent of a monovinylidene aromatic copolymer; and

(C) from 0J to 15 weight parts of an epoxy-containing alkene copolymer.

2. The composition of Claim 1 wherein the ratio of Component (A) to Component (B) is from 40:60 to 85: 15.

3. The composition of Claim 1 comprising from 1 to 10 parts of Component (C).

4. The composition of Claim 1 comprising from 2 to 8 parts of Component (C).

5. The composition of Claim 1 wherein the monovinylidene aromatic copolymers are derived from a monovinylidene aromatic monomer comprising styrene or alpha- methylstyrene, and a comonomer comprising acrylonitrile, methyl methacrylate, maleic anhydride, or N-phenyl maleimide.

6. The composition of Claim 1 wherein the emulsion polymerized rubber- modified copolymer comprises a styrene/acrylonitrile grafted rubber and a methyl methacrylate/styrene grafted elastomer.

7. The composition of Claim 1 wherein the epoxy-containing alkene copolymer comprises a copolymer of ethylene, glycidyl methacrylate and, optionally, at least one additional ethylenically unsaturated compound comprising vinyl acetate or methyl acrylate.

8. The composition of Claim 1 wherein the epoxy-containing alkene copolymer comprises glycidyl methacrylate.

9. The composition of Claim 1 which comprises: from 40 to 85 weight parts of the aromatic carbonate polymer; from 15 to 60 weight parts of the combination of monovinylidene aromatic copolymers (B), and from 1 to 10 weight parts of an epoxy- containing alkene copolymer.

10. The composition of Claim 9 which comprises: from 20 to 80 weight percent of the mass polymerized rubber-modified copolymer (B1); from 80 to 20 weight percent of the emulsion polymerized, rubber-modified copolymer (B2); and from 0 to 60 percent of the monovinylidene aromatic copolymer (B3).