HEAT-EXPANDABLE MICROSPHERE, PROCESS FOR PRODUCING THE SAME, AND USE

摘要

A heat-expandable microsphere which comprises a shell comprising a thermoplastic resin and a blowing agent which is enclosed therein and has a boiling point not higher than the softening point of the thermoplastic resin, wherein the expansion ratio after maximum expansion is 50 or higher and the hollow microsphere obtained by heat expansion has durability in repeated compression of 75% or higher. Also provided is a process for producing heat-expandable microspheres which includes the steps of dispersing an oily mixture comprising a polymerizable ingredient and the blowing agent into an aqueous dispersion medium containing a specific water-soluble compound and polymerizing the polymerizable ingredient contained in the oily mixture.