Polysiloxane composition

Patent metadata

Field	Value
Publication number	US-11339291-B2
Application number	US-201817056576-A
Country	US
Kind code	B2
Filing date	May 18, 2018
Priority date	May 18, 2018
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

Viscosity peaking during initial formulation of condensation curing compositions employing silanol-functional organopolysiloxanes and alkoxysilanes is avoided by employing specific titanium compounds. A curing catalyst which may be a titanium compound or a tin compound may be added following disappearance of silanol functionality.

First claim

What is claimed is:

1. A polysiloxane composition comprising the following ingredients:
(a) a hydroxyl-terminated polyorganosiloxane;
(b) a multifunctional alkoxysilane; and
(c) an organotitanium compound having the following general formula I or II, or a multipolymer thereof having a degree of polymerization of from 2 to 10,
(i) an organotitanium compound I with the following formula I,

where n is an arbitrary integer between 1 and 4,
R 1 is a saturated monovalent hydrocarbon group having from 1 to 16 carbon atoms,
R 2 is a saturated divalent hydrocarbon group having from 1 to 16 carbon atoms,
R 3 is a saturated monovalent hydrocarbon group having from 1 to 32 carbon atoms,
wherein the hydrocarbon groups are linear and/or branched;
(ii) an organotitanium compound II with the following general formula II,

where m is an arbitrary integer between 2 and 4,
R 4 is a saturated monovalent hydrocarbon group having from 1 to 16 carbon atoms,
R 5 is a saturated divalent hydrocarbon group having from 1 to 16 carbon atoms,
R 6 is a saturated monovalent hydrocarbon group having from 4 to 32 carbon atoms,
wherein the hydrocarbon groups are linear and/or branched; and
optionally,
further comprising a catalyst (d).

2. The polysiloxane composition of claim 1 , wherein ingredient (a) is employed in an amount of from 10 wt % to 85 wt % and ingredient (c) from 0.01 wt % to 2 wt %, based on the total weight of the starting materials of the polysiloxane composition.

3. The polysiloxane composition of claim 1 , wherein ingredient (b) is employed in an amount of from 0.5 wt % to 5 wt % and ingredient (c) from 0.01 wt % to 2 wt %, based on the total weight of the starting materials of the polysiloxane composition.

4. The polysiloxane composition of claim 1 , wherein ingredient (a) contains at least one hydroxyl-terminated polyorganosiloxane having a kinematic viscosity at 25° C. ranging from 1,000 to 100,000 mm 2 /s.

5. The polysiloxane composition of claim 4 , wherein ingredient (a) is employed in an amount of from 50 wt % to 85 wt %, based on the total weight of the starting materials of the polysiloxane composition.

6. The polysiloxane composition of claim 1 , wherein ingredient (b) is a vinyl group-containing multifunctional alkoxysilane.

7. The polysiloxane composition of claim 1 , wherein in the organotitanium compound of the formula I or II, R 1 or R 4 is a saturated monovalent hydrocarbon group having from 2 to 4 carbon atoms.

8. The polysiloxane composition of claim 1 , wherein in the organotitanium compound of the formula I or II, R 2 or R 5 is a saturated divalent hydrocarbon group having from 3 to 5 carbon atoms.

9. The polysiloxane composition of claim 1 , wherein ingredient (d) is an organotitanium catalyst (d1) or an organotin catalyst (d2).

10. The polysiloxane composition of claim 9 , wherein ingredient (c) is employed in an amount of from 0.01 wt % to 2 wt % and ingredient (d1) from 0.1 wt % to 5 wt %, based on the total weight of the starting materials of the polysiloxane composition.

11. The polysiloxane composition of claim 1 , further comprising a filler (e1), which contains fumed silica and is in an amount of from 1 wt % to 20 wt %, based on the total weight of the starting materials of the polysiloxane composition.

12. The polysiloxane composition of claim 1 , which further comprises a filler (e2), which contains no fumed silica and is in an amount of from 10 wt % to 60 wt %, based on the total weight of the starting materials of the polysiloxane composition.

13. The polysiloxane composition of claim 1 , further comprising an adhesion promoter (f).

14. The polysiloxane composition of claim 13 , wherein ingredient (f) is an epoxy silane, when the polysiloxane composition comprises an organotitanium catalyst (d1), or ingredient (f) is an aminosilane, when the polysiloxane composition comprises an organotin catalyst (d2).

15. A method for preparing a polysiloxane composition of claim 1 , comprising:
mixing ingredients (a)-(c) and reacting until silanol groups in ingredient (a) substantially disappear; and
optionally, in a further step adding ingredient (d) after the silanol groups in ingredient (a) have substantially disappeared.

Assignees

• Wacker Chemie Ag

Inventors

• Nie Jian
• Yang Lei

Classifications

• C08K5/56

  Organo-metallic compounds, i.e. organic compounds containing a metal-to-carbon bond · CPC title

• C08K3/36 Primary

  Silica · CPC title

• C08F283/122

  on to saturated polysiloxanes containing hydrolysable groups, e.g. alkoxy-, thio-, hydroxy- · CPC title

• C08K3/013

  Fillers, pigments or reinforcing additives · CPC title

• C08K5/544

  containing nitrogen · CPC title