| 摘要 |
1300233 Expandable thermoplastic polymer beads KANEGAFUCHI KAGAKU KOGYO KK 23 Dec 1969 62675/69 Heading C3C An expandable styrene and/or its derivative polymer bead contains a homogenous mixture of a metal salt of an aliphatic or aromatic carboxylic acid in amount of 2% by wt. or less, the metal of the salt belonging to Group II of the Mendeleef Periodic Table, and an expanding agent which is gaseous at 10‹ C. and atmospheric pressure. The expandable beads may be made by polymerizing the monomers in aq. suspension in the presence of the metal salt and either in the presence of the expanding agent, or if in its absence then impregnating the resultant beads with the expanding agent. In examples the polymer was polystyrene or a copolymer of styrene and methyl methacrylate, the expanding agent was butane and/or pentane, and/or tetrachloroethylene, and the metal salt was calcium stearate, palmitate or laurate, cadmium cumate or n-butyl-benzoate, or zinc p-tert.- butyl-benzoate. |
