Abstract: The present invention concerns a process for producing a synthetic resin foam composed of cells having substantially two sizes, one of the sizes being at most 0.3 mm and the other size as being 0.4 to 1 mm, comprising the steps of:forming a mixture of one or more of a water-absorbent high molecular compound, a cell-controlling agent, a synthetic resin, and water; melting the mixture with heating; incorporating a volatile type foaming agent into the mixture under pressure; and extruding the mixture into a lower pressure space to form a foam.

Abstract: An extruded synthetic resin foam comprises a cell structure of substantially two different cell sizes, the smaller size being not more than about 0.25 mm while the other size is from about 0.4 to about 1 mm. The cells are dispersed in an island in the sea manner. A foam such as a styrenic foam is produced by forming a mixture of synthetic resin, a fine mineral powder having hydroxyl groups, and a cell controlling agent, incorporating a volatile foaming agent and extruding the mixture to form a foam. The powder has a particle size of not more than 1000 nm and may be a silica having silanol groups.

Abstract: An extruded synthetic resin foam comprises a cell structure of substantially two different cell sizes, the smaller size being not more than about 0.25 mm while the other size is from about 0.4 to about 1 mm. The cells are dispersed in an island in the sea manner. A foam such as a styrenic foam is produced by forming a mixture of synthetic resin, a fine mineral powder having hydroxyl groups, and a cell controlling agent, incorporating a volatile foaming agent and extruding the mixture to form a foam. The powder has a particle size of not more than 100 nm and may be a silica having silanol groups.

Abstract: A vinyl chloride polymer for providing a vinyl chloride paste which has a good thermal stability, a stability to sol viscosity and an excellent air release capability in the natural state or in a short period of time under a moderately low pressure is produced by using, in the production thereof, as an emulsifying agent, the alkali metal salts and/or ammonium salts of a mixture of a major amount of olefin alkyl sulfonates and a minor amount of hydroxyalkyl sulfonates (hereinafter olefin alkyl/hydroxyalkyl sulfonates) having from about 8 to 20 carbon atoms, in the polymerization thereof or in the preparation of a vinyl chloride paste from the polymerized product.