Claims
- 1. A polymeric composition expandable in atmospheric steam to a cellular structure consisting essentially of (1) a solid alkenyl aromatic polymer having a glass transition temperature between about 60.degree. to about 100.degree. C. selected from the group consisting of polymerized monomers of styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, and ar-bromostyrene; solid copolymers of two or more alkenyl aromatic monomers selected from the group consisting of styrene, alpha-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, ar-chlorostyrene, and ar-bromostyrene; and solid copolymers of alkenyl aromatic monomers selected from the group consisting of styrene, alpha-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, ar-chlorostyrene, and ar-bromostyrene, with acrylonitrile, maleic anhydride, itaconic anhydride or rubber-reinforced styrene; and (2) a volatile blowing agent comprising a mixture of from about 40 to about 90% by weight of a primary blowing agent comprising dichlorodifluoromethane, and from about 10 to about 60% by weight of a secondary blowing agent comprising a halogenated hydrocarbon, a hydrocarbon, or an aliphatic alcohol containing from 1 to 4 carbon atoms, said hydrogenated hydrocarbon, hydrocarbon, or aliphatic alcohol having a normal atmospheric boiling point of from about 0.degree. to about 100.degree. C.
- 2. The composition of claim 1 in which said alkenyl aromatic polymer is polystyrene.
- 3. The composition of claim 1 in which said alkenyl aromatic polymer is a copolymer of styrene and acrylonitrile.
- 4. The composition of claim 1 in which said volatile blowing agent is present in an amount of from 10-30 parts per hundred of said alkenyl aromatic polymer.
- 5. The composition of claim 4 in which said volatile blowing agent comprises from about 60 to about 80% by weight dichlorodifluoromethane and from about 20 about 40% by weight trichloromonofluoromethane.
- 6. The composition of claim 1 further including an azido functional silane as a crosslinking agent.
- 7. A cellular expanded polymeric composition further expandable in atmospheric steam to a foam of lower density consisting essentially of (1) a solid alkenyl aromatic polymer having a glass transition temperature between about 60.degree. to about 100.degree. C. selected from the group consisting of polymerized monomers of styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, and ar-bromostyrene; solid copolymers of two or more alkenyl aromatic monomers selected from the group consisting of styrene, alpha-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, ar-chlorostyrene, and ar-bromostyrene; and solid copolymers of alkenyl aromatic monomers selected from the group consisting of styrene, alpha-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ar-methyl styrene, ar-vinylxylene, ar-chlorostyrene, and ar-bromostyrene, with acrylonitrile, maleic anhydride, itaconic anhydride or rubber-reinforced styrene; and (2) a volatile blowing agent comprising a mixture of from about 40 to about 90% by weight of a primary blowing agent comprising dichlorodifluoromethane, and from about 10 to about 60% by weight of a secondary blowing agent comprising a halogenated hydrocarbon, a hydrocarbon, or an aliphatic alcohol containing from 1 to 4 carbon atoms, said hydrogenated hydrocarbon, hydrocarbon, or aliphatic alcohol having a normal atmospheric boiling point of from about 0.degree. to about 100.degree. C.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a division of application Ser. No. 777,992 filed Sept. 20, 1985, which is a continuation-in-part of U.S. Application Ser. No. 672,001, filed Nov. 16, 1984.
US Referenced Citations (11)
Divisions (1)
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Number |
Date |
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Parent |
777992 |
Sep 1985 |
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Continuation in Parts (1)
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Number |
Date |
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672001 |
Nov 1984 |
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