Thermally foamable microsphere and production process thereof

摘要

The invention provides a thermally foamable micro-sphere whose shell is formed of a polymer that is obtained by the polymerization of a polymerizable monomer and a crosslinkable monomer at a proportion of greater than 1% by weight up to 5% by weight based on the polymerizable monomer and which has a maximum expansion ratio of at least 5. The invention also provides a process for the production of a thermally foamable microsphere having a maximum expansion ratio of at least 5 by the suspension polymerization of a polymerizable mixture containing a crosslinkable monomer at a proportion of greater than 1% by weight up to 5% by weight based on the polymerizable monomer.