	US 11,939,446 B2
	Thermally expandable thermoplastic microspheres and process for their preparation
Christina Nyholm, Sundsvall (SE); Per Anders Restorp, Sävedalen (SE); Anders Törncrona, Bohus (SE); Helena Bergenudd, Sundsvall (SE); Andreas Sundblom, Alingsås (SE); and Bo Andreasson, Sundsvall (SE)
Assigned to NOURYON CHEMICALS INTERNATIONAL B.V., Arnhem (NL)
Appl. No. 16/311,258
Filed by Akzo Nobel Chemicals International B.V., Arnhem (NL)
PCT Filed Jul. 11, 2017, PCT No. PCT/EP2017/067349 § 371(c)(1), (2) Date Dec. 19, 2018, PCT Pub. No. WO2018/011182, PCT Pub. Date Jan. 18, 2018.
Claims priority of application No. 16179524 (EP), filed on Jul. 14, 2016.
Prior Publication US 2019/0233606 A1, Aug. 1, 2019
Int. Cl. C08J 9/20 (2006.01); B01D 39/04 (2006.01); B01J 13/06 (2006.01); B01J 13/14 (2006.01); B01J 13/16 (2006.01); C08J 9/14 (2006.01); C08J 9/22 (2006.01); C08K 3/36 (2006.01); C08K 9/06 (2006.01)

CPC C08J 9/20 (2013.01) [B01D 39/04 (2013.01); B01J 13/06 (2013.01); B01J 13/14 (2013.01); B01J 13/16 (2013.01); C08J 9/141 (2013.01); C08J 9/22 (2013.01); C08K 3/36 (2013.01); C08K 9/06 (2013.01); C08J 2203/22 (2013.01); C08J 2300/22 (2013.01); C08J 2333/12 (2013.01); C08J 2333/20 (2013.01); C08J 2339/06 (2013.01)]

21 Claims

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.