BLENDS OF A SILICONE-POLYCARBONATE BLOCK COPOLYMER WITH A COMPATIBILIZED ALLOY OF POLYPHENYLENE ETHER RESIN/POLYESTER RESIN

Abstract: Blends of a silicone-polycarbonate block copolymer with a compatibilized alloy of polyphenylene ether and polyester resins comprise a class of thermoplastic materials witn physical properties ranging from those of a self-extinguishing, tough thermoplastic elastomer to a rigid engineering material. The compatibilizers include aromatic polycarbonates and rubber-modified impact modifiers.

Description: The present invention relates to novel compositions comprised of a silicone-polycarbonate block copolymer and a polyphenylene ether resin/polyester resin blend. More specifically, the present invention relates to blends of a silicone-polycarbonate block copolymer with a blend of polyphenylene ether/polyester, wherein the blend contains a minor amount of one or more compatibilizers which serves to effect or improve compatibility between the polyphenylene ether resin and the polyester resin. The compositions of the present invention comprise a novel class of thermoplastic materials with physical properties ranging from those of a self-extinguishing, tough thermoplastic elastomer to a rigid engineering material. Silicone-polycarbonate block copolymers are known in the art. For example, Vaughn et al., U.S-A-3,189,662, disclose organopolysiloxane-polycarbonate block copolymers and a method for preparing them. The reference mentions that the described copolymers are useful as surface coatings for appliances, as insulation, as coatings for rods and wires, as binding material for parts and laminates, and in adhesive formulations. The reference does not mention blending such silicone-polycarbonate block copolymers with any other thermoplastic or thermoset resin copolymer or blend thereof. Molari, U.S-A-4,027,012 and Re. 32,406, discloses polycarbonate laminates in which the laminae are bonded by polysiloxane-polycarbonate block copolymers. It is also known that polyphenylene ether and polyester resins can be blended together along with reinforcements and/or flame retardant additives to produce thermoplastic compositions with various desired properties such as flame retardance and reduced melt viscosity. For example, Abolins et al., U.S-A-4,013,613, disclose thermoplastic compositions which include admixtures of polyphenylene ether and polyester resins. Included within the thermoplastic compositions of the patentees are those wherein the admixtures of resins are in combination with a reinforcing amount of a reinforcing filler. In combination, the three-component thermoplastic compositions included within the invention are those which do not delaminate or separate when cooled, and those which do not manifest a failure to form structurally useful compositions because of reduced gross physical properties, chemical resistance, macroscopic appearance and the like. Betts et al., EP-A 0133641, disclose flame retardant thermoplastic compositions of admixtures of a polyester resin and a flame retardant agent comprised of a combination of a polyphenylene ether resin, an organic phosphate and a stable brominated material. Lee, U.S-A-4,123,410, discloses a thermoplastic composition of an admixture comprised of polyphenylene ether, a plasticizer and an amount of a polyester sufficient to reduce the melt viscosity of said composition without substantially reducing the heat distortion temperature and ductility properties. The preferred amount of polyester is 2-5% by weight. Also, Lee et al., U.S-A-4,206,154, disclose self-extinguishing thermoplastic molding compositions comprising a polyphenylene ether resin, a styrene resin, a halogenated aromatic flame retardant, ferrocene and from 1-15% by weight of a fatty-acid terminated saturated polyester. Seiler et al., U.S-A-4,672,086 disclose self-extinguishing thermoplastic polyester molding materials containing a linear aromatic polyester resin, a polyphenylene ether resin, a phosphate-containing compound and a filler. The compositions may optionally contain an aromatic polycarbonate. EP-A-0073067 discloses thermoplastic compositions comprising aromatic polyesters having improved impact strength in which the aromatic polyesters are blended with a siloxane-polyarylene polyether block copolymer and/or a siloxane polycarbonate block copolymer and optionally an aliphatic polyester. The blend may also optionally contain polycarbonates and poly(aryl ethers). In accordance with the invention, there are provided thermoplastic compositions comprising : A thermoplastic composition consisting of, based on the total weight of components (a) and (b) (a) 10% to 90% of a blend of (i) a polyphenylene ether resin; (ii) a polyester resin containing repeating units of the formula where n is a whole number from 2 to 10 (iii) 5 to 50% by weight of said blend of a compatibilizer for (i) and (ii) selected from aromatic polycarbonates and rubber-modified impact modifiers selected from hydrogenated or non-hydrogenated A-B-A¹ block copolymers wherein, prior to hydrogenation, terminal blocks A and A¹ are the same or different polymerized aromatic vinyl compounds and central block B is a polymerized conjugated diene; and rubber-modified alkenyl aromatic resins, and (b) 10% to 90% of a silicone-polycarbonate block copolymer. In those embodiments of the present invention where component (b) is present in an amount greater than 50% by weight based upon 100% by weight of (a) and (b) combined, the compositions can provide thermoplastic materials which are tough thermoplastic elastomers and self-extinguishing. In those embodiments of the present invention where component (a) is present in an amount greater than 50% by weight based upon 100% by weight of (a) and (b) combined, the compositions can provide rigid engineering materials which exhibit a good cross-section of physical properties. A full range of properties are obtainable through variations in the compositions. In addition, the inclusion of other property-improving components in property-improving amounts can effect desirable further improvements in the compositions. In accordance with the present invention, a silicone-polycarbonate copolymer is admixed with a compatibilized blend of a polyphenylene ether resin and a polyester resin. The preferred silicone-polycarbonate block copolymers ("copolymers") of the present invention, in general, comprise a class of thermoplastic elastomers which exhibit low temperature ductility and are self-extinguishing. Such copolymers can be represented by the average Formula I: wherein n is at least 1, and preferably n is an integer equal to from 1 to 1000, inclusive; a is equal to from 1 to 200, inclusive; and b is from 1 to 100 and, preferably, has an average value of from 15 to 90, inclusive; while the ratio of a to b can vary from 0.05 to 3, inclusive, and when b has an average value of from 15 to 90 inclusive, the ratio of a to b is preferably from 0.067 to 0.45, inclusive; d is 1 or more; Y is A is selected from hydrogen and R is selected from hydrogen, monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, R' is a selected from monovalent hydrocarbon radicals and cyanoalkyl radicals, R'' is selected from monovalent hydrocarbon radicals and halogenated hydrocarbon radicals, and Z is selected from hydrogen, lower alkyl radicals and halogen radicals and mixtures thereof. Included within the radicals represented by R of Formula I are aryl radicals and halogenated aryl radicals such as phenyl, chlorophenyl, xylyl and tolyl; aralkyl radicals such as phenylethyl and benzyl; aliphatic, haloaliphatic and cycloaliphatic radicals such as alkyl, alkenyl, cycloalkyl and haloalkyl, including methyl, ethyl, propyl, chlorobutyl, and cyclohexyl. The R radicals can be all the same or any two or more of the aforementioned radicals, and are preferably methyl. R' includes all radicals included by R above except hydrogen, where all of the R' radicals can be the same or any two or more of the aforementioned R radicals except hydrogen. R' is preferably methyl. R' also includes, in addition to all the radicals included by R, except hydrogen, cyanoalkyl radicals such as cyanoethyl and cyanobutyl radicals. Radicals that are included within the definition of Z of Formula I are hydrogen, methyl, ethyl, propyl, chloro, bromo and iodo and combinations thereof. Z is preferably hydrogen. The copolymers useful in the present invention can be further described as comprising recurring copolymeric units of a polydiorganosiloxane joined by substituted aryloxy-silicon linkages to a polyester or dihydric phenol and a precursor of carbonic acid, where each of said recurring copolymeric units comprises by average weight from 10 to 75% of the polydiorganosiloxane, and preferably from 40 to 70% by weight. The copolymers of Formula I can be produced by reacting at temperatures in the range of 0° to 100° C., preferably 20° to 50° C., and in the presence of an acid acceptor, a mixture of a halogen chain-stopped polydiorganosiloxane having the Formula II: and a dihydric phenol having the Formula III: and thereafter phosgenating said reaction product until the resulting copolymer achieves a maximum intrinsic viscosity, where R, R', Z and b are as defined above, and X is a halogen radical, preferably chloro. The halogen chain-stopped polydiorganosiloxanes of Formula II can be made by conventional procedures such as by the controlled hydrolysis of a diorganodihalosilane, for example, dimethyldichlorosilane as taught in Patnode U.S-A-2,381,366 and Hyde U.S-A-2,629,726 and 2,902,507. Another procedure that can be employed involves equilibrating a mixture of a diorganodichlorosilane and a cyclic polydiorganosiloxane in the presence of a metal cataylst such as ferric chloride as shown in Sauer U.S-A-2,421,653. Although the various procedures utilized in forming the halogen chain-stopped polysiloxane are not critical, generally it has been found desirable to maintain the halogen content of the resulting halogen chain-stopped polysiloxane in the range of 0.4 to 35% by weight, and preferably in the range of from 1 to 10% by weight of the halogen chain-stopped polysiloxane. The halogen chain-stopped polysiloxane is preferably in the form of a chlorinated polydimethylsiloxane. Dihydric phenols that are included in Formula III are, for example, 2,2-bis(4-hydroxyphenyl)-propane (bis-phenol-A); 2,4'-dihydroxydiphenylmethane; bis-(2-hydroxyphenyl)-methane; bis-(4-hydroxyphenyl)-methane; 1,1-bis-(4-hydroxyphenyl)-ethane; 1,2-bis(4-hydroxyphenyl)-ethane; 1,1-bis(4-hydroxy-2-chlorophenyl)-ethane; 1,1-bis(2,5-dimethyl-4-hydroxyphenyl)-ethane; 1,3-bis-(3-methyl-4-hydroxyphenyl)- propane; 2,2-bis-(3-isopropyl-4-hydroxyphenyl)-propane. Mixtures can also be used. Others will occur to those skilled in the art. Materials of the above nature are also described in U.S-A-3,189,662 and can be used either alone as such or in conjunction with well known modifiers to provide particular desired characteristica. Illustrative of the above block copolymers is General Electric LR-3320. This material has a specific gravity of 1.12, a tensile strength of (2500 to 3900 psi) 17.22 to 26.87 MPa, an elongation of 230 to 430%, a tear strength (Die C) of (230-430 lbs./in.) 41-76.8 kg/cm, a brittleness temperature below (-76° F) -60°C and a heat deflection temperature ((10 mils) 0.254 mm under (66 psi) 455 kPa load) of (160° F) 71.1°C. Another such block copolymer, specifically General Electric LR-5630, has a specific gravity of 1.07, a tensile strength of (2200 to 2500 psi) 15.16 to 17.22 MPa an elongation of 500 to 700%, a tear strength (Die C) of about (200 lbs./in) 35.7 kg/cm, a brittleness temperature below (-76° F) -60°C and a heat deflection temperature ((66 psi) 455 kPa of (130° F) 54.4°C. The polyphenylene ether resin component is a homo- or copolymer having units of the formula wherein Q, Q', Q'' and Q''' are independently selected from hydrogen, halogen, hydrocarbon radicals, halohydrocarbon radicals, hydocarbonoxy radicals, and halohydrocarbonoxy radicals; and n represents the total number of monomer units, and is an integer at least about 20, and preferably at least 50. In general, the polyphenylene ether resins are self-condensation products of monohydric monocyclic phenols produced by reacting the phenols with oxygen in the presence of complex metal cataysts, with molecular weight being controlled by reaction time, longer times providing a higher average number of repeating units. Particular procedures are known to those skilled in the art and are described in the patent literature, including U.S-A-3,306,874 and 3,306,875 (to Allan Hay), and U.S-A-3,257,357 and 3,257,358 (to Gelu Stamatoff). Illustrative polymers which can be produced by such procedures and which are within the above general formula are: poly(2,6-dilauryl-1,4-phenylene)ether; poly(2,6-diphenyl-1,4-phenylene)ether; poly(2,6-dimethoxy-1,4-phenylene)ether; poly(2,6-diethoxy-1,4-phenylene)ether; poly(2-methoxy-6-ethoxy-1,4-phenylene)ether; poly(2-ethyl-6-stearyloxy-1,4-phenylene)ether; poly(2,6-dichloro-1,4-phenylene)ether; poly(2-methyl-6-phenyl-1,4-phenylene)ether; poly(2,6-dibenzyl-1,4-phenylene)ether; poly(2-ethoxy-1,4-phenylene)ether; poly(2-chloro-1,4-phenylene)ether; poly(2,6-dibromo-1,4-phenylene)ether. Examples of other polyphenylene ethers corresponding to the above formula can be found in the above reference patents of of Hay and Stamatoff. Also included are polyphenylene ether copolymers, such as copolymers of 2,6-dimethylphenol with other phenols, for example, with 2,3,6-trimethylphenol or 2-methyl-6-butylphenol. One preferred copolymer is poly(2,6-dimethyl-co-2,3,6-trimethyl-1,4-phenylene) ether. For purposes of the present invention, an especially preferred family of polyphenylene ethers includes those having alkyl substitution in the two positions ortho to the oxygen ether atom, i.e., those of the above formula wherein Q and Q' are alkyl, most preferably having from 1 to 4 carbon atoms. Illustrative members of this class are: poly(2,6-dimethyl-1,4-phenylene)ether; poly(2,6-diethyl-1,4-phenylene)ether; poly(2-methyl-6-ethyl-1,4-phenylene)ether; poly(2-methyl-6-propyl-1,4-phenylene)ether; poly(2,6-dipropyl-1,4-phenylene)ether; poly(2-ethyl-6-propyl-1,4-phenylene)ether. The most preferred polyphenylene ether resin for purposes of the present invention is poly(2,6-dimethyl-1, 4-phenylene)ether. The polyphenylene ether resins useful in the compositions of this invention can be prepared by following known procedures, including those described by Allan Hay in U.S-A-3,306,874 and 3,306,875 and by Gelu Stamatoff in U.S-A-3,257,357 and 3,257,358. The polyesters which may be employed as a component in the present compositions are in general relatively high in molecular weight, may be branched or linear, and are normally flammable thermoplastic polymers. Polyesters suitable for compositions of the present invention include, in general, linear saturated condensation products of diols and dicarboxylic acids, or reactive derivatives thereof. Preferably, they are polymeric glycol esters of terephthalic acid and isophthalic acid. These polymers are available commercially or can be prepared by known techniques, such as by the alcoholysis of esters of the phthalic acid with a glycol and subsequent polymerization, by heating glycols with the free acids or with halide derivatives thereof. Such polymers and methods of their preparation are described further by Whinfield et al., in U.S-A-2,465,319 and by Pengilly in U.S-A-3,047,539. Preferred polyesters are of the family consisting of high molecular weight, polymeric glycol terephthalates or isophthalates having repeating units of the formula where n is a whole number from two to ten, and more usually from two to four, and mixtures of such esters, including copolyesters of terephthalic and isophthalic acids of up to 30 mol percent isophthalic units. Especially preferred polyesters are poly(ethylene terephthalate) and poly(1,4-butylene terephthalate). Especially favored when high melt strength is important are branched high melt viscosity poly(1,4-butylene terephthalate) resins which include small amounts, for example, up to 5 mol percent based on the terephthalate units, of a branching component containing at least three ester forming groups. The branching component can be one which provides branching in the acid unit portion of the polyester, or in the glycol unit portion, or it can be a hybrid. Illustrative of such branching components are tri- or tetracarboxylic acids, such as trimesic acid, pyromellitic acid, and lower alkyl esters thereof, or preferably, polyols, and especially preferably, tetrols, such as pentaerythritol, triols, such as trimethylolpropane, or dihydroxy carboxylic acids and hydroxydicarboxylic acids and derivatives, such as dimethyl hydroxyterephthalate. The branched poly(1,4-butylene terephthalate) resins and their preparation are described in Borman U.S-A-3,953,404. Illustratively, the high molecular weight polyesters useful in the practice of this invention have an intrinsic viscosity of at least about 0.2 deciliters per gram, and more usually from 0.4 to 1.5 deciliters per gram as measured in solution in ortho-chlorophenol or a 60/40 phenol/tetrachloroethane mixture at 25° to 30° C. Also useful are copolyesters, such as segmented copolyesters having a multiplicity of recurring etherester and/or ester units as described by Witsiepe in U.S-A-3,651,014; 3,763,109; and 3,766,146. The polyphenylene ether resin and the polyester resin components of the present invention are in general thermodynamically immiscible, and small amounts of compatibilizers are usually employed in blends of such resins. Aromatic polycarbonates and rubber-modified impact modifiers are effective as compatibilizers to effect or improve compatibilization between the two resins. Suitable aromatic polycarbonates can be prepared by polycondensation at the phase boundary, for example by the process described in DE-A-1,300,266 or by transesterification of diphenyl carbonate with bisphenol-A by the process described in German Laid-Open Application DOS No. 1,495,730. Bisphenol-A may be replaced with as much as 30 mol % of other aromatic bishydroxy compounds, in particular 2,2-bis-(4-hydroxyphenyl)-pentane, 2,6-dihydroxy-naphthalene, bis-(4-hydroxyphenyl) sulfone, bis-(4-hydroxyphenyl) ether, bis-(4-hydroxyphenyl) sulfide, bis-(4-hydroxyphenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane or 4,4'dihydroxydiphenyl. Particularly suitable aromatic polycarbonates for the purpose according to the invention are those which have a relative viscosity (measured at 25°C. on a 0.5% strength by weight solution in methylene chloride) of from 1.2 to 1.5, preferably from 1.28 to 1.40. The aromatic polycarbonate resins can be made in known ways and they are available commercially. The rubber modified impact modifiers which generally are blended intimately with the polyphenylene ether resin/polyester resin mixture to effect or improve compatibilization can be selected from elastomeric A-B-A¹ block copolymers wherein terminal blocks A and A¹ are the same or different and are derived from a vinyl aromatic compound, e.g., styrene, α-methyl styrene, vinyl toluene, vinyl xylene and vinyl naphthalene; and center block B is derived from a conjugated diene, e.g., butadiene, isoprene, 1,3-pentadiene and 2,3-dimethyl butadiene. These can be made by an organometallic initiated polymerization process using for example, sodium or lithium metal or an organic deivative thereof. The diene monomers can be polymerized with a monofunctional or difunctional initiator, as is described in Kennedy et al., Interscience publishers, Vol. 23, Part II (1969), pages 553-559. Other methods of preparation are described in Zelinski, U.S-A-3,251,905 and Holden et al., U.S-A-3,231,635. The relative ratios of the polymer units in the A-B-A¹ block copolymers can vary broadly. It is preferred that the center block B have a molecular weight greater than that of the combined terminal blocks. In general, the molecular weight of each of the respective terminal blocks will range from 2,000 to 100,000 and the molecular weight of the center block will range from 65,000 to 1,000,000. Hydrogenated A-B-A¹ block copolymers can also be used and are also well known. In general, these are block copolymers of the A-B-A¹ type in which terminal blocks A and A¹ are the same or different and, prior to hydrogenation, comprise homopolymers or copolymers derived from vinyl aromatic hydrocarbons and, especially, vinyl aromatics wherein the aromatic moiety can be either monocyclic or polycyclic. Examples of the monomers are styrene, α-methyl styrene, vinyl xylene, ethyl vinyl xylene, and vinyl naphthalene. Center block B will always be derived from a conjugated diene, e.g., butadiene, isoprene and 1,3pentadiene. Preferably, center block B will be comprised of polybutadiene or polyisoprene. The preparation of hydrogenated A-B-A¹ block copolymers is described in Jones, U.S-A-3,431,323. Also suitable are rubber-modified alkenyl aromatic resins, for example, rubber-modified high impact polystyrene. Examples of suitable alkenyl aromatic resins for compositions of the present invention are polystyrene, poly-p-methylstyrene, poly-α-methylstyrene, styrene/α-methylstyrene, styrene/acrylonitrile, styrene/methyl acrylate, styrene/butyl acrylate, styrene/methyl methacrylate, styrene/butadiene, styrene/maleic anhydride and styrene/acrylonitrile/butadiene copolymers, copolymers of ethylvinylbenzene and divinylbenzene, and styrene/butadiene polymers modified with acrylic resins. Mixtures of homopolystyrene and the above copolymers are also useful. The rubber modifiers for the above alkenyl aromatic resins are elastomeric polymers. As a rule, such high impact styrene polymers contain from 2 to 20% by weight of an elastomeric polymer. Preferred elastomeric polymers have a glass transition temperature (Tg) of less than 0°C., in particular less than -20°C. Suitable elastomeric polymers are natural rubber, polybutadiene, polyisoprene, copolymers of butadiene and/or isoprene with styrene, a C₂-C₈-alkyl acrylate or acrylonitrile, polymers of C₂-C₈-alkyl acrylates, polyisobutylene and elastomeric copolymers composed of ethylene, propylene and dienes. In the polyphenylene ether resin/polyester resin blend , the polyphenylene ether resin can be present in a wide range of proportions, i.e., from 10-90% by weight, preferably 30-70% by weight and more preferably 40-60% of the two resins, with the polyester forming the balance of 100% by weight. Also present in the blend are minor amounts of compatibilizers such as bisphenol - A polycarbonates and rubber - modified impact modifiers, which are present in an amount at least sufficient to effect or improve compatibility between the polyphenylene ether resin and the polyester resin. The compatibilizers may be used alone or in combination and are present in an amount of from 5-50% by weight, preferably less than 30% by weight, more preferably less than 25% by weight and most preferably less than 10% by weight, relative to 100% by weight of the polyphenylene ether resin/polyester resin blend. In addition, the compositions of this invention may include optional constituents such as additives to improve flame retardance or minor amounts of polyethylene, tridecylphosphite, mineral reinforcing agents such as zinc oxide, zinc sulfide and various types of fillers such as clays. The novel materials may also contain, as a further component, effective amounts of any additives and/or assistants as conventionally used for thermoplastic polymers for molding materials. Examples of such additives and/or assistants are plasticizers, dyes, pigments, antistatic agents, antioxidants, lubricants and mold release agents. The following examples illustrate the invention. Silicone-polycarbonate block copolymer, Copel® 3320 (a registered trademark of the General Electric Company), is blended with each of two polyphenylene ether ("PPE")/poly(1,4-butylene terephthalate) ("PBT") alloys (1 and 2, Table I) to form the following Copel®: PPE/PBT alloy (an alloy of Copel®, PPE and PBT) ratios: 10/90, 20/80, 30/70, 50/ 50, 70/ 30. 80/20, and 90/10. The materials were compounded in a Werner-Pfleiderer K-28 twin screw extruder after tumble mixing in a plastic bog. The screw RPM's were maintained at 280-290, and the melt temperature varied from about 316 (600) to 330°C (625°F). PPE/PBT/POLYCARBONATE ALLOY FORMULATIONS No. 1 No. 2 Poly(2,6 dimethyl-1,4-phenylene)ether 30 30 Rubber Modified polystyrene -- 5 Impact Modifier (S-EB-S) 8 8 Poly(bisphenol-A carbonate) 0.6 I.V. -- 8 Poly(bisphenol-A carbonate) 1.3 I.V. 8 -- poly(1,4-butylene terephthalate) 45 45 Stabilizers and antioxidants 1.5 1.5 The pelletized extrudes were dried at about 100° C for 1-3 hours prior to injection molding into test specimens with a 118.3 cm³ (4 oz.) Newbury machine. The barrel temperature was maintained at 860°C (500°F). Mold temperatures varied between 66-77°C (150-170° F). The properties listed in Tables II and III for blends of Copel® and PPE/PBT alloys Nos. 1 and 2, respectively, indicate that compositions containing 50% or more Copel® resin exhibit elastomeric properties. The rheological characteristics of these materials show surprisingly little dependence upon composition and self-extinguishing flame resistance (V-0 or V-1) is retained. For those compositions containing less than 50% Copel® resin, much improved impact strength and ductility are achieved with the PPE/PBT No. 2 formulation which contains 5 pbw rubber modified polystyrene. Other modifications and variations of the invention are possible in light of the above disclosure. For instance, instead of poly(1,4-butylene terephthalate) or poly(ethylene terephthalate) individually, mixtures of these two can be employed. Copolyesters can also be substituted for the homopolymeric polyesters shown.

Claims: A thermoplastic composition consisting of, based on the total weight of components (a) and (b) (a) 10% to 90% of a blend of (i) a polyphenylene ether resin; (ii) a polyester resin containing repeating units of the formula where n is a whole number from 2 to 10, (iii) 5 to 50% by weight of said blend of a compatibilizer for (i) and (ii) selected from aromatic polycarbonates and rubber-modified impact modifiers selected from hydrogenated or non-hydrogenated A-B-A¹ block copolymers wherein, prior to hydrogenation, terminal blocks A and A¹ are the same or different polymerized aromatic vinyl compounds and central block B is a polymerized conjugated diene; and rubber-modified alkenyl aromatic resins and (b) 10% to 90% of a silicone-polycarbonate block copolymer. The composition according to Claim 1 wherein said silicone-polycarbonate block copolymer is of the formula: wherein n is an integer equal to from 1 to 1000, inclusive; a is equal to from 1 to 200, inclusive; and b is from 1 to 100, inclusive; the ratio of a to b can vary from 0.05 to 3, inclusive: d is 1 or more: Y is A is a member selected from hydrogen and R is a member selected from hydrogen, monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, R' is a member selected from monovalent hydrocarbon radicals and cyanoalkyl radicals, R'' is a member selected from monovalent hydrocarbon radicals and halogenated hydrocarbon radicals, and Z is a member selected from hydrogen, lower alkyl radicals, halogen radicals and mixtures thereof. The composition according to Claim 1 wherein said polyphenylene ether is poly(2,6-dimethyl-1,4-phenylene oxide). The composition according to Claim 1 wherein said polyphenylene ether is poly(2,6 dimethyl-co-2,3,6-trimethyl-1,4-phenylene)ether. The composition according to Claim 1 wherein said polyester is poly(1,4-butylene terephthalate). The composition according to Claim 1 wherein said polyester is poly(ethylene terephthalate). The composition according to Claim 1 wherein said aromatic polycarbonate is bisphenol-A polycarbonate. The composition according to Claim 1 wherein said compatibilizer comprises rubber-modified polystyrene. The composition according to Claim 2 wherein said compatibilizer comprises bisphenol-A polycarbonate and rubber-modified polystyrene. The composition according to Claim 1 wherein said compatibilized blend contains at least 70% by weight in combination, of said polyester resin and polyphenylene ether resin, based on 100% by weight of (a)(i), (a)(ii) and (a)(iii). The composition according to Claim 1 wherein said compatibilized blend contains 34% by weight of said polyphenylene ether, 49% by weight of said polyester, and 17% by weight of said compatibilizer based on 100% by weight of (a)(i), (a)(ii) and (a)(iii). The composition according to Claim 1 containing 50% or more by weight of said silicone-polycarbonate copolymer. The composition according to Claim 1 wherein said compatibilizer comprises 5% by weight of rubber-modified polystyrene and 8% by weight of bisphenol-A polycarbonate based on 100% by weight of (a)(i), (a)(ii) and (a)(iii). The composition according to Claim 1 wherein the composition contains 50% or more of compatibilized blend.

Inventors: BOPP, RICHARD CHARLES, YATES, JOHN BENNIE
Applicants: GENERAL ELECTRIC COMPANY
Application year: 1989
Main classification: C08L83
IPC codes: C08L83, C08L69, C08L71, C08L67