Silicone elastomer composition

Patent metadata

Field	Value
Publication number	US-11261329-B2
Application number	US-201716489459-A
Country	US
Kind code	B2
Filing date	Dec 15, 2017
Priority date	Dec 16, 2016
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

The present invention provides a tin-free, room temperature curable silicone elastomer composition, wherein the uncured composition is a putty.

First claim

The invention claimed is:

1. A tin-free, room temperature curable silicone elastomer composition in the form of a putty and comprising the following components:
a) an end-capped base polymer, wherein the end-capped base polymer comprises a polysiloxane or mixture of polysiloxanes and has a viscosity of at least 150,000 mPa·s at 25° C., and wherein the end-capped base polymer comprises terminal di-(C 2-4 )alkoxy silyl groups;
b) 2 to 20 parts by weight of at least one particulate reinforcing filler for each 100 parts by weight of end-capped base polymer;
c) 0.15 to 7 parts by weight of at least one ultra-low density filler for each 100 parts by weight of end-capped base polymer, wherein the mean true density of the or each at least one ultra-low density filler is from 0.022 to 0.076 g/cm 3 ;
d) (10×(ρF/2.8)) to (120×(ρF/2.8)) parts by weight of at least one particulate non-reinforcing filler for each 100 parts by weight of end-capped base polymer, wherein μF is the mean true density (g/cm 3 ) of the at least one particulate non-reinforcing filler; and
e) a curing catalyst consisting of one or more selected from the group consisting of organic titanates and organic zirconates.

2. The composition according to claim 1 , which has a Williams plasticity of from 100 to 350 at 25° C.

3. The composition according to claim 1 , which is a one-part silicone elastomer composition.

4. The composition according to claim 1 , wherein the end-capped base polymer comprises one type or more than one type of monomer of the following general formula:

wherein R 1 and R 2 are independently selected from the group consisting of linear or branched (C 1-6 )alkyl groups, linear or branched (C 2-6 )alkenyl groups, linear or branched (C 2-4 )haloalkyl groups and phenyl groups.

5. The composition according to claim 1 , wherein the end-capped base polymer comprises a hydroxy-terminated polysiloxane or mixture of hydroxy-terminated polysiloxanes.

6. The composition according to claim 1 , wherein the terminal di-(C 2-4 )alkoxy silyl groups have the general formula
—SiR a (OR b )(OR c )

wherein:
R a is selected from the group consisting of a linear or branched (C 1-10 )alkyl group, a linear or branched (C 2-8 )alkenyl group and a (C 6-10 )aryl group, each of which groups may be optionally substituted by one or more substituents selected from the group consisting of halogens, a cyano group, an aminyl group, an NUR′, group, an —NHR e group, an —OR c group, a —C(═O)R c group, a —C(═O)OR c group, a carboxyl group, a glycidyl group and a sulfanyl group, wherein each R e and R f group is independently selected from the group consisting of linear or branched (C 1-6 )alkyl groups; and
R b and R c are independently selected from the group consisting of (C 2-4 )alkyl groups.

7. The composition according to claim 6 , wherein R a is selected from the group consisting of a methyl group and a vinyl group.

8. The composition according to any of claim 6 , wherein R b and R c are independently selected from the group consisting of ethyl, n-propyl and iso-propyl groups.

9. The composition according to claim 1 , wherein the end-capped base polymer is the reaction product of a hydroxy-terminated polysiloxane or mixture of hydroxy-terminated polysiloxanes and an end-capping reagent comprising a tri-(C 2-4 )alkoxy silane.

10. The composition according to claim 9 , wherein the tri-(C 2-4 )alkoxy silane has the general formula:
—SiR a (OR b )(OR c )(OR d )

wherein:
R a is selected from the group consisting of a linear or branched (C 1-10 )alkyl group, a linear or branched (C 2-8 )alkenyl group and a (C 6-10 )aryl group, each of which groups may be optionally substituted by one or more substituents selected from the group consisting of halogens, a cyano group, an aminyl group, an —NHR e , group, an —NR e R f group, an —OR e group, a —C(═O)R e group, a —C(═O)OR e group, a carboxyl group, a glycidyl group and a sulfanyl group, wherein each R e and R f group is independently selected from the group consisting of linear or branched (C 1-6 )alkyl groups;
R b and R c are independently selected from the group consisting of (C 2-4 )alkyl groups; and
R d is a (C 2-4 )alkyl group.

11. The composition according to claim 1 , wherein the organic titanates and organic zirconates are represented by the following general formula:
M(OR) a (C) 4-a

wherein:
M is Ti or Zr;
each R may be the same or different and represents a linear or branched (C 1-12 )alkyl group;
each C may be the same or different and represents a ligand having the following general formula:

wherein R′ and R″ are independently selected from the group consisting of a linear or branched (C 1-6 )alkyl group and a linear or branched (C 1-6 )alkoxy group; and
a is an integer from 0 to 4.

12. The composition according to claim 1 , wherein the at least one particulate non-reinforcing filler is a combination of at least one granular non-reinforcing filler having an average particle size (D50) of at least 5 μm and at least one filler having a needle-like structure.

13. The composition according to claim 1 , wherein the composition additionally comprises an adhesion promoter which is one or more selected from the group of compounds having the following general formula:

wherein:
n is an integer from 2 to 10; and
R X is a linear or branched (C 1-6 )alkyl group.

14. The composition according to claim 1 , wherein the composition further comprises at least one fibrous filler.

15. A method of preparing a cured silicone elastomer comprising curing the composition according to claim 1 .

16. A cured silicone elastomer prepared by the method according to claim 15 .

17. A packaged silicone elastomer composition comprising the composition according to claim 1 within a sealed packaging, wherein the sealed packaging has a water vapour transmission rate (WVTR) of less than 0.1 g/m 2 /day.

18. A method of producing a cured silicone elastomer composition comprising exposing the composition according to claim 1 to moisture.

Assignees

• Tesa Se

Inventors

• Ariscrisna Priti
• Dowden Tom
• Pullen Jude
• Buckingham Mark
• Jerlhagen Åsa
• Shamsah Reya
• Christogianni Paraskevi
• Gautrot Julien
• Westall Steve
• Nguyen Khai Duong Quang
• Mac Winnie

Classifications

• C08L83/04 Primary

  Polysiloxanes · CPC title

• C08K7/02

  Fibres or whiskers · CPC title

• C08G77/18

  to alkoxy or aryloxy groups · CPC title

• C08K5/1515

  Three-membered rings · CPC title

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title