Carbonate blend composition having improved resistance to environmental stress cracking

摘要

The present invention relates to carbonate blend compositions demonstrating improved environmental stress crack resistance in combination with an excellent blend of impact, thermal, and physical properties. Said carbonate blend composition comprises a polycarbonate, a polyester, and a silicon-containing graft (co)polymer having a core-shell morphology, comprising a shell that contains (co)polymerized alkyl(meth)acrylate and glycidyl methacrylate grafted to a composite rubber core that contains polyorganosiloxane and poly(meth)alkyl acrylate components and methods to make said compositions.

主权项

1. A carbonate blend composition comprising:
(i) an aromatic polycarbonate or an aromatic polyester carbonate having a melt flow rate of from 3 to 20 g/10 min determined at 300° C. and a load of 1.2 kg present in an amount of from 5 parts to 65 parts; (ii) an aromatic polyester- having a degree of crystallinity of from 25 to 60 percent present in an amount of greater than 30 parts to 95 parts; and (iii) a silicon-containing graft (co)polymer having a core-shell morphology, comprising: (iii.a) a composite rubber core that contains polyorganosiloxane and poly(meth)alkyl acrylate components, and (iii.b) a grafted shell that comprises (co)polymerized glycidyl(meth)acrylate and alkyl(meth)acrylate components present in an amount of from 0.5 to 25 parts, wherein the composition has a polycarbonate or aromatic polyester carbonate phase and an aromatic polyester phase wherein at least 90 percent of the silicon-containing graft (co)polymer having a core-shell morphology is present in the aromatic polyester phase and has a crystallinity of at least 9 percent; and exhibits good chemical resistance to one or more of bleach, ethanol, 3.4 weight percent glutaraldehyde in water, 6.43 weight percent of organic phenols in water or about 17 percent of quaternary germicides in water according to ASTM D 543-06 such that the ratio of break stress of chemically exposed samples to non exposed samples is greater than or equal to 90 percent and the ratio of break strain of chemically exposed samples to non exposed samples is from 80 to 139 percent, and parts are by weight based to the weight of the carbonate blend composition.