Patent ID: 11939446
Assignee: NOURYON CHEMICALS INTERNATIONAL B.V.
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A process for the manufacture of thermally expandable thermoplastic microspheres, the process comprising:
providing a mixture of monomeric materials suitable for polymerisation to form a thermoplastic polymer and at least one blowing agent,
providing a colloidal silica that is surface-modified with at least hydrophobic organosilane groups;
contacting the mixture of one or more monomers and at least one blowing agent with the surface-modified colloidal silica and forming an o/w emulsion comprising droplets of the mixture of one or more monomers and the at least one blowing agent in an aqueous phase; and
polymerising the one or more monomers in the droplets to form an aqueous slurry and/or wet cake of thermally expandable thermoplastic microspheres,
wherein the colloidal silica is modified with the hydrophobic organosilane groups that are alkylsilyl groups, vinylsilyl groups, and/or phenylsilyl groups, and is further surface-modified with hydrophilic organosilane groups being glycerol propyl silyl groups.