| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low-density foam which is reduced in environmental impact and can be produced easily with a low-pressure foaming machine by foaming and simultaneously polymerizing and cross-linking anα,β-unsatd. carboxylic acid in the presence of a metal (bi)carbonate and a polymn. initiator. SOLUTION: This foam comprises a (co)polymer cross-linked with a metal salt and comprising structural units derived from anα,β-unsated. carboxylic acid and, if necessary, structural units derived from another vinyl monomer and is produced by conducting the foaming of a monomer with a metal (bi)carbonate simultaneously with the polymn. of at least a part of the monomer. This foam is obtd. by a process wherein anα,β-unsatd. carboxylic acid, if necessary, another vinyl monomer are polymerized, cross-linked, and foamed in the presence of a metal (bi)carbonate and a polymn. initiator if necessary under heating, or by a process wherein anα,β-unsatd. carboxylic acid copolymer and anα,β-unsatd. carboxylic acid and/or another vinyl monomer are polymerized, cross-linked, and foamed in the presence of a metal (bi)carbonate and a polymn. initiator if necessary under heating. |
