POLYESTER-POLYCARBONATE COMPOSITION AND ARTICLE
A composition includes specific amounts of an aromatic polycarbonate, a block polycarbonate-polysiloxane, a poly(alkylene terephthalate), a block polyestercarbonate, and an organophosphate ester. Relative to a corresponding composition lacking the block polyestercarbonate, the composition exhibits improved solvent resistance while substantially maintaining impact strength, melt flow, and flame retardancy. The composition is useful for fabricating articles that may come into contact with liquid chemicals or chemical vapors.
1 . A composition comprising, based on the total weight of the composition:
5 to 50 weight percent of an aromatic polycarbonate;
10 to 40 weight percent of a block polycarbonate-polysiloxane;
5 to 35 weight percent of a poly(alkylene terephthalate);
5 to 50 weight percent of a block polyestercarbonate comprising
a polyester block comprising resorcinol ester repeat units having the structure
and
a polycarbonate block comprising carbonate repeat units having the structure
wherein at least 60 percent of the total number of R 1 groups are aromatic; and
4 to 20 weight percent of an organophosphate ester.
2 . The composition of claim 1 , wherein the aromatic polycarbonate comprises repeat units having the structure
wherein at least 60 percent of the total number of R 1 groups are aromatic.
3 . The composition of claim 1 , wherein the aromatic polycarbonate comprises repeat units having the structure
4 . The composition of claim 1 , wherein the block polycarbonate-polysiloxane comprises a polycarbonate block comprising repeat units having the structure
wherein at least 60 percent of the total number of R 1 groups are aromatic, and
a polysiloxane block comprising siloxane repeat units having the structure
wherein each occurrence of R 2 is independently C 1 -C 13 hydrocarbyl.
5 . The composition of claim 1 , wherein the block polycarbonate-polysiloxane comprises, based on the weight of the block polycarbonate-polysiloxane, 70 to 90 weight percent of carbonate units of the formula
and
10 to 30 weight percent of dimethylsiloxane units.
6 . The composition of claim 1 , wherein the poly(alkylene terephthalate) comprises alkylene groups comprising ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,4-cyclohexylene, 1,4-cyclohexanedimethylene, or a combination thereof.
7 . The composition of claim 1 , wherein the poly(alkylene terephthalate) comprises poly(butylene terephthalate).
8 . The composition of claim 1 , wherein the polyester block comprises resorcinol ester repeat units having the structures
and
wherein the polycarbonate block comprises carbonate repeat units having the structure
9 . The composition of claim 1 , comprising 0 to 1 weight percent of impact modifiers.
10 . The composition of claim 1 , comprising 0 to 1 weight percent of reinforcing fillers.
11 . The composition of claim 1 , comprising 0 to 1 weight percent of any polymer other than the aromatic polycarbonate, the block polycarbonate-polysiloxane, the poly(alkylene terephthalate), the block polyestercarbonate, and, optionally, up to 2 weight percent of a poly(styrene-acrylonitrile)-encapsulated polytetrafluoroethylene.
12 . The composition of claim 1 , comprising
15 to 36 weight percent of the aromatic polycarbonate,
20 to 30 weight percent of the block polycarbonate-polysiloxane,
15 to 25 weight percent of the poly(alkylene terephthalate),
20 to 35 weight percent of the block polyestercarbonate, and
5 to 12 weight percent of the organophosphate ester.
13 . The composition of claim 1 ,
wherein the aromatic polycarbonate comprises repeat units having the structure
wherein the block polycarbonate-polysiloxane comprises, based on the weight of the block polycarbonate-polysiloxane, 70 to 90 weight percent of carbonate units of the formula
and 10 to 30 weight percent of dimethylsiloxane units;
wherein the poly(alkylene terephthalate) comprises poly(butylene terephthalate);
wherein the block polyestercarbonate comprises a polyester block comprising resorcinol ester repeat units having the structures
and
a polycarbonate block comprising carbonate repeat units having the structure
wherein the organophosphate ester comprises bisphenol A bis(diphenyl phosphate); and
wherein the composition comprises
15 to 36 weight percent of the aromatic polycarbonate,
20 to 30 weight percent of the block polycarbonate-polysiloxane,
15 to 25 weight percent of the poly(alkylene terephthalate),
20 to 35 weight percent of the block polyestercarbonate, and
5 to 12 weight percent of the organophosphate ester.
14 . An article comprising a composition comprising, based on the total weight of the composition:
5 to 50 weight percent of an aromatic polycarbonate;
10 to 40 weight percent of a block polycarbonate-polysiloxane;
5 to 35 weight percent of a poly(alkylene terephthalate);
5 to 50 weight percent of a block polyestercarbonate comprising
a polyester block comprising resorcinol ester repeat units having the structure
and
a polycarbonate block comprising carbonate repeat units having the structure
wherein at least 60 percent of the total number of R 1 groups are aromatic; and
4 to 20 weight percent of an organophosphate ester.
15 . The article of claim 14 , wherein the article is selected from a component of a household appliance, a component of office equipment, and a component of a consumer electronic device.
16 . The article of claim 14 ,
wherein the aromatic polycarbonate comprises repeat units having the structure
wherein the block polycarbonate-polysiloxane comprises, based on the weight of the block polycarbonate-polysiloxane, 70 to 90 weight percent of carbonate units of the formula
and 10 to 30 weight percent of dimethylsiloxane units;
wherein the poly(alkylene terephthalate) comprises poly(butylene terephthalate);
wherein the block polyestercarbonate comprises a polyester block comprising resorcinol ester repeat units having the structures
and
a polycarbonate block comprising carbonate repeat units having the structure
wherein the organophosphate ester comprises bisphenol A bis(diphenyl phosphate); and
wherein the composition comprises
15 to 36 weight percent of the aromatic polycarbonate,
20 to 30 weight percent of the block polycarbonate-polysiloxane,
15 to 25 weight percent of the poly(alkylene terephthalate),
20 to 35 weight percent of the block polyestercarbonate, and
5 to 12 weight percent of the organophosphate ester.