CONTROL OF INTERNAL VISCOSITY IN IN SITU POLYMERIZED ORGANOPOLYSILOXANE EMULSIONS

• US 20150274970A1
• Filed: 03/26/2014
• Published: 10/01/2015
• Est. Priority Date: 03/26/2014
• Status: Abandoned Application

• Current Assignee: Wacker Chemical Corporation
• Original Assignee: Wacker Chemical Corporation
• Inventors: Larson, Michael
• Application Number:
  US14/225,514
• Publication Number:
  US 20150274970A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08G 77/16 to hydroxyl groups
• CPC Class Codes: C08K 5/05 Alcohols; Metal alcoholates
• CPC Class Codes: C08K 5/42 Sulfonic acids; Derivatives thereof
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

Aqueous emulsions of in situ-polymerized hydroxyl-functional organopolysiloxanes prepared in the presence of an acid catalyst and an alkanol have lower neat fluid viscosities than otherwise similar polymers prepared in the absence of the alkanol.

Claims

1. A process for the manufacture of an in situ-polymerized organopolysiloxane aqueous emulsion, comprising

a) polymerizing at least one di- or polyhydroxyl functional organopolysiloxane fluid in aqueous emulsion in the presence of an effective emulsifying amount of at least one emulsifier, and in the presence of at least one acid polymerization catalyst;

b) adding at least one alkanol to the aqueous emulsion of step a) prior to completion of polymerization;

c) optionally, neutralizing the acid polymerization catalyst, and

d) recovering an aqueous emulsion of an in situ-polymerized organopolysiloxane,

wherein the neat viscosity of the in situ-polymerized organopolysiloxane is lower than an organopolysiloxane prepared similarly but with no alkanol added.

2. The process of claim 1, wherein the di- or polyhydroxyl-functional organopolysiloxane fluid is an α

,ω

-dihydroxypolydiorganosiloxane.

3. The process of claim 2, wherein the α

,ω

-dihydroxypolydiorganosiloxane has the formula

4. The process of claim 3, wherein R each are selected from the group consisting of C_1-4 alkyl and phenyl.

5. The process of claim 3, wherein R is methyl.

6. The process of claim 1, wherein at least one alkanol has the formula

R¹—

OH

where R¹ is an optionally substituted C_1-40 aliphatic group or a C_5-40 cycloaliphatic, or arylaliphatic group.

7. The process of claim 1, wherein the alkanol is a C_1-14 aliphatic alkanol.

8. The process of claim 1, wherein the acid polymerization catalyst is a polyoxyalkylene polymer bearing a covalently bound acid group.

9. The process of claim 1, wherein the acid polymerization catalyst is an emulsifier bearing at least one covalently bonded acid group.

10. The process of claim 3, wherein the α

,ω

-dihydroxy polydiorganosiloxane has a viscosity at 25°

C. of from 5 to 80,000 mm²/s.

11. The process of claim 1, wherein the alkanol of step b) is added to the di- or polyhydroxyl functional organopolysiloxane prior to emulsifying the di- or polyhydroxyl-functional in water to form an aqueous emulsion.

12. The process of claim 1, wherein in step a), a mixture (a1) of water, emulsifier(s), and acid catalyst(s) is first prepared, and the di- or polyhydroxyl functional organopolysiloxane is then admixed with agitation to form the aqueous emulsion.

13. The process of claim 12, wherein the alkanol is first blended with the di- or polyhydroxyl functional organopolysiloxane prior to emulsifying the di- or polyhydroxyl functional organopolysiloxane in the mixture (a1).

14. The process of claim 1, wherein the acid catalyst is at least partially neutralized.

15. The process of claim 14, wherein the acid catalyst is at least partially neutralized by adding an organic amine, an alkanolamine, or mixture thereof

16. An aqueous emulsion of an in situ-polymerized organopolysiloxane, prepared by the process of claim 1.

17. An aqueous emulsion of an in situ-polymerized organopolysiloxane, prepared by the process of claim 2.

18. An aqueous emulsion of an in situ-polymerized organopolysiloxane, prepared by the process of claim 6.

19. An aqueous emulsion of an in situ-polymerized organopolysiloxane, prepared by the process of claim 8.