Aromatic polyesters having improved properties

Claim 1

A thermoplastic polymeric molding composition comprising, in admixture, (a) a linear aromatic polyester of components comprising a bisphenol and a dicarboxylic acid, where said carboxylic acid has the formula: ##STR3## wherein Z is alkylene, --Ar or --Ar--Y--Ar--, where Ar is aromatic, Y is alkylene, haloalkylene, --O--, --S--, --SO--, --SO 2 --, --SO 3 --, --CO, GP<═O or GN<n is 0 or 1, and G is alkyl, haloalkyl, aryl, haloaryl, alkylaryl, haloalkylaryl, arylalkyl, haloarylalkyl, cycloalkyl, and halocycloalkyl, and (b) a rubber-modified copolymer comprising the reaction product of (1) a monovinyl alkenyl aromatic monomer containing up to 12 carbon atoms and having the alkenyl group attached directly to the benzene nucleus, said alkenyl aromatic compound being present in a proportion of from about 65 to about 85 parts by weight based on 100 parts by weight of said rubber-modified copolymer, and from about 10 to about 35 parts by weight of an unsaturated dicarboxylic anhydride readily copolymerizable therewith, and (2) from about 5 to about 35 parts by weight of a rubber in the form of a plurality of particles having diameters within the range of 0.02 to 30 microns dispersed throughout a matrix of the polymer of (1), at least a major portion of the rubber particles containing occlusions of the polymerization product of (1).