Foamable polycarbonate compositions, articles and methods

Claim 1

A foamable thermoplastic composition substantially free of fibrous fillers, said composition comprising (a) an aromatic polycarbonate, an aromatic polyester carbonate, an aromatic dihydric sulfone carbonate, or a mixture of any of the foregoing, in combination with (b) a polyester resin comprising units of an aliphatic diol, a cycloaliphatic diol, or a mixture of said diols and an aromatic diacid or a cycloaliphatic diacid, (c) a minor effective amount of a foaming agent; and (d) from about 0.1 to about 5.0 parts by weight of a non-fibrous particulate foam nucleating agent substantially insoluble in the composition and consisting of a particulate acrylate polymer, the amounts of (c) and (d) being sufficient to provide a rigid substantially void-free, substantially uniform cellular core within a solid integral skin, said composition also including a surface active agent compound comprising a silicone, a polyglycol ether, a fatty acid derivative or a mixture of any of the foregoing in an amount sufficient to help particulate dispersion and to reduce surface tension.

Claim 15

A method of preparing foamed thermoplastic compositions comprising A. combining in the substantial absence of fibrous fillers, a composition comprising (a) an aromatic polycarbonate, an aromatic polyester carbonate, an aromatic dihydric phenol sulfone carbonate, or a mixture of any of the foregoing, in combination with (b) a polyester resin comprising units of an aliphatic diol, a cycloaliphatic diol or a mixture of said diols and an aromatic diacid or a cycloaliphatic diacid, (c) a minor effective amount of a foaming agent, and (d) from about 0.1 to about 5.0 parts by weight of a non-fibrous particulate foam nucleating agent substantially insoluble in the composition consisting of a particulate acrylate polymer, said composition also including a surface active agent comprising a silicone, a polyglycol ether, a fatty acid derivative or a mixture of any of the foregoing in an amount sufficient to help particulate dispersion and to reduce surface tension, and B. heating said composition in a confined space above a temperature at which polymer components (a) and (b) soften and foaming agent (c) decomposes to release a gas, until formation of a rigid substantially uniform cellular structure is complete.

Claim 16

A method of preparing foamed thermoplastic compositions comprising A. combining in the substantial absence of fibrous fillers, a composition comprising (a) an aromatic polycarbonate, an aromatic polyester carbonate, an aromatic dihydric phenol sulfone carbonate, or a mixture of any of the foregoing, in combination with (b) a polyester resin comprising units of an aliphatic diol, a cycloaliphatic diol or a mixture of said diols and an aromatic diacid or a cycloaliphatic diacid, (c) a minor effective amount of a foaming agent, and (d) from about 0.1 to about 5.0 parts by weight of a non-fibrous particulate foam nucleating agent substantially insoluble in the composition consisting of a particulate acrylate polymer, said composition also including a surface active agent comprising a silicone, a polyglycol ether, a fatty acid derivative or a mixture of any of the foregoing in an amount sufficient to help particulate dispersion and to reduce surface tension, and B. heating said composition in a confined space above a temperature at which polymer components (a) and (b) soften and foaming agent (c) decomposes to release a gas, until formation of a rigid substantially uniform cellular structure is complete.

Claim 17

A method of preparing foamed thermoplastic compositions comprising: A. combining in the substantial absence of fillers having an aspect ratio of greater than about 1.0, a composition comprising (a) poly(bisphenol-A carbonate), in combination with (b) poly(ethylene terephthalate), (c) from about 0.02 to about 2.0 parts by weight of a dihydrooxadiazinone foaming agent, and (d) from about 0.1 to 5.0 parts by weight of a non-fibrous particulate foam nucleating agent consisting of a particulate acrylate polymer, said composition also including a surface active agent compound comprising a silicone, a polyglycol ether, a fatty acid derivative or a mixture of any of the foregoing in an amount sufficient to help particulate dispersion and to reduce surface tension, said amount being from 0.01 to about 5.0 parts by weight, the parts by weight being based on 100 parts by weight total of (a), (b), (c) and (d), and B. heating said composition in a confined space above a temperature at which polymer components (a) and (b) soften and foaming agent (c) decomposes to release a gas, until formation of a rigid substantially uniform cellular structure is complete.

Claim 18

A method of preparing foamed thermoplastic compositions comprising: A. combining in the substantial absence of fillers having an aspect ratio of greater than about 1.0, a composition comprising (a) poly(bisphenol-A carbonate), in combination with (b) poly(ethylene terephthalate), (c) from about 0.02 to about 2.0 parts by weight of a dihydrooxadiazinone foaming agent, and (d) from about 0.1 to 5.0 parts by weight of a non-fibrous particulate foam nucleating agent consisting of a particulate acrylate polymer, said composition also including a surface active agent compound comprising a silicone, a polyglycol ether, a fatty acid derivative or a mixture of any of the foregoing in an amount sufficient to help particulate dispersion and to reduce surface tension, said amount being from 0.01 to about 5.0 parts by weight, the parts by weight being based on 100 parts by weight total of (a), (b), (c) and (d), and B. heating said composition in a confined space above a temperature at which polymer components (a) and (b) soften and foaming agent (c) decomposes to release a gas, until formation of a rigid substantially uniform cellular structure is complete.