Heat-expandable macrosphere and process for producing the same
AssigneeKureha Corporation
InventorsYoshikatsu Satake, Genzo Asai
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Abstract
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.
Claims24
A thermally foamable microsphere having a structure in which a foaming agent is encapsulated in a shell formed of a polymer, wherein:
- (1) the shell formed of a polymer is formed of a polymer that is obtained by polymerization of a polymerizable monomer and a crosslinkable monomer used at a proportion of greater than 1% by weight up to 5% by weight based on the polymerizable monomer, and
- (2) a maximum expansion ratio of the thermally foamable microsphere is at least 5.
A process for producing a thermally foamable microsphere having a structure in which the foaming agent is encapsulated in a shell formed a polymer that is obtained by subjecting a polymerizable mixture containing at least a foaming agent, a polymerizable monomer and a crosslinkable monomer to suspension polymerization in an aqueous dispersion medium, the process comprising subjecting the polymerizable mixture containing the crosslinkable monomer at a proportion of greater than 1% by weight up to 5% by weight based on the polymerizable monomer to suspension polymerization to obtain a thermally foamable microsphere having a maximum expansion ratio of at least 5.
Dependencies are inferred from the claim text.