Patent ID: 8206826
Filing Date: 2012-06-26
Classification: B01J,C08F,Y10T

Abstract:
1. A method of producing heat-expandable microspheres, each comprising a shell of thermoplastic resin and a blowing agent encapsulated therein having a boiling point not higher than the softening point of the thermoplastic resin, the method comprising the step of: polymerizing a polymerizable component in an aqueous dispersing medium in the presence of at least one water-soluble compound; wherein the polymerizable component and the blowing agent mentioned above are dispersed in the aqueous dispersing medium, and the water-soluble compound is selected from the group consisting of oxygen-containing aluminum salts and/or their hydrates, and polyalkyleneimines having a molecular weight not lower than 1000 and at least one bond of a nitrogen atom and an alkyl group which is substituted with a hydrophilic functional group selected from the group consisting of carboxylic acid (salt) groups and phosphonic acid (salt) groups, wherein the aluminum salt further contains an atom of a typical element selected from the group consisting of nitrogen and sulfur.