US 12,331,163 B2
Method for preparing polyorganosiloxanes
Shuai Tian, Shanghai (CN); Huifeng Duan, Shanghai (CN); and Heng Yang, Shanghai (CN)
Assigned to Wacker Chemie AG, Munich (DE)
Appl. No. 17/608,518
Filed by WACKER CHEMIE AG, Munich (DE)
PCT Filed May 6, 2019, PCT No. PCT/CN2019/085595
§ 371(c)(1), (2) Date Nov. 3, 2021,
PCT Pub. No. WO2020/223863, PCT Pub. Date Nov. 12, 2020.
Prior Publication US 2022/0227944 A1, Jul. 21, 2022
Int. Cl. C08G 77/16 (2006.01); C08G 77/04 (2006.01); C08G 77/06 (2006.01); C08G 77/08 (2006.01); C08G 77/10 (2006.01); C08G 77/18 (2006.01); C08G 77/20 (2006.01); C08G 77/38 (2006.01)
CPC C08G 77/16 (2013.01) [C08G 77/08 (2013.01); C08G 77/10 (2013.01); C08G 77/18 (2013.01); C08G 77/20 (2013.01); C08G 77/38 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for preparing polyorganosiloxanes, comprising the followings steps:
a) reacting together a hydroxyl-terminated polysiloxane of Formula I and a dialkoxysilane of Formula II or an oligomer thereof in the presence of Catalyst 1,

OG Complex Work Unit Chemistry
where p is an arbitrary integer between 10 and 60,
R1 is a methyl or ethyl group,
R2 is a C6-C18 alkyl group,
R3 is a C1-C18 alkyl group,
q is an arbitrary integer between 1 and 8;
b) reacting the product of Step a) by a chain scission reaction with an endcapper in the presence of Catalyst 2 to form the said polyorganosiloxane;
wherein the endcapper has the structural formula as shown in Formula IV and/or V below:

OG Complex Work Unit Chemistry
where t is an arbitrary integer between 0 and 20, and R4 is a C1-C6 alkyl group, and
wherein the endcapper is used in an amount to provide 0.2-0.5 moles of vinyl groups per mole of silanol groups in the hydroxyl-terminated polysiloxane.