Silicone elastomer compositions and elastomeric materials

Patent metadata

Field	Value
Publication number	US-12378413-B2
Application number	US-201917442670-A
Country	US
Kind code	B2
Filing date	Mar 29, 2019
Priority date	Mar 29, 2019
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

Provided herein is a self-lubricating silicone elastomer composition and a self-lubricating, elastomeric material made therefrom which has a low coefficient of friction and avoids the need for “self-bleeding”. The self-lubricating silicone elastomer composition comprises: (i) 50 to 75% by weight of one or more polydiorganosiloxane polymer(s) containing from 0.01 to 0.1% by weight of alkenyl and/or alkynyl content; (ii) 3 to 15% by weight of a polydiorganosiloxane polymer having ≥0.5% by weight of alkenyl or alkynyl content; (iii) 10 to 35% by weight of reinforcing filler; and either or both of (iv) a peroxide catalyst; or (v) a hydrosilylation catalyst package.

First claim

What is claimed is:

1. A self-lubricating silicone elastomer composition, comprising:
(i) 50 to 75% by weight of one or more polydiorganosiloxane polymer(s) containing from 0.01 to 0.1% by weight of alkenyl content;
(ii) 3 to 15% by weight of a polydiorganosiloxane polymer having ≥0.5% by weight of alkenyl content;
(iii) 10 to 35% by weight of reinforcing filler; and either
(iv) a peroxide catalyst; or
(v) a hydrosilylation catalyst package comprising
(a) a polydiorganosiloxane polymer having at least 2 Si-H groups per molecule; and
(b) a hydrosilylation catalyst; or

(vi) a combination of (iv) and (v); and

further comprising:
(vii) polytetrafluoroethylene;
wherein components (i) and (ii) comprise fluorosilicone gums, the self-lubricating silicone elastomer composition is hydrosilylation curable, and the polydiorganosiloxane polymer (v) (a) is fluoro containing.

2. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein each of components (i) and (ii) have a Williams plasticity of >30 mm/100 in accordance with ASTM D-926-08.

3. The self-lubricating silicone elastomer composition in accordance with claim 2 , wherein each of components (i) and (ii) have a Williams plasticity of from 100 mm/100 to 400 mm/100 in accordance with ASTM D-926-08.

4. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein the polytetrafluoroethylene (vii) is present in an amount of from 0.75 to 5% by weight.

5. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein the reinforcing filler (iii) is a treated fumed silica, precipitated silica, silica aerogel or a mixture thereof.

6. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein when component (v) is present there is additionally provided a hydrosilylation cure inhibitor in an amount of from 0 to 1% by weight of the composition.

7. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein when component (v) is present, the composition is stored in two parts, a first part, Part A, comprising components (i), (iii) and (v) (b) and a second part, Part B, which comprises components (i), (iii), and (v) (a), and wherein component (ii) is present in Part A, or Part B, or divided between Part A and Part B.

8. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein the polytetrafluoroethylene (vii) has a particle size of from 250 to 750 μm.

9. The self-lubricating silicone elastomer composition in accordance with claim 8 , comprising polytetrafluoroethylene (vii) having a particle size of from 350 to 550 μm.

10. The self-lubricating silicone elastomer composition in accordance with claim 9 , wherein the polytetrafluoroethylene (vii) is present in an amount of from 0.75 to 5% by weight.

11. The self-lubricating silicone elastomer composition in accordance with claim 9 , comprising polytetrafluoroethylene (vii) having an average particle size of between 400 and 500 μm.

12. The self-lubricating silicone elastomer composition in accordance with claim 1 , which is non-oil bleeding and/or non-oil filled.

13. The self-lubricating silicone elastomer composition in accordance with claim 1 , further comprising one or more of compatibilising agents, electrical and thermally conductive fillers, non-conductive fillers, pot life extenders, flame retardants, non-reinforcing fillers, pigments, coloring agents, adhesion promoters, chain extenders, silicone polyethers, and mixtures thereof.

14. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein component (v) (a) is a polydiorganosiloxane polymer having at least 3 Si-H groups per molecule.

15. The self-lubricating silicone elastomer composition in accordance with claim 1 , wherein components (i) and (ii) each include vinyl groups.

16. A self-lubricating silicone elastomeric material which is the cured product of the composition in accordance with claim 1 .

17. The self-lubricating silicone elastomeric material in accordance with claim 16 , having a post cured kinetic coefficient of friction of >0 and ≤0.8 or having a post cured kinetic coefficient of friction of >0 and ≤1.25 in the case of a fluorosilicone elastomeric material.

18. The self-lubricating silicone elastomeric material in accordance with claim 16 , adapted for use in straps and bands of wearable devices, protection covers for mobile phones and other personal electronic devices, catheters, gaskets and/or seals for healthcare applications, wiper blades, connector seals, matt seals, wire seals kitchenware, sanitation articles, insulators and/or arresters for high voltage industry.

19. A device selected from straps and bands of wearable devices, protection covers for mobile phones and other personal electronic devices, catheters, gaskets and/or seals for healthcare applications, wiper blades, connector seals, matt seals, wire seals kitchenware, sanitation articles, insulators and/or arresters for high voltage industry, which consists or comprises of the self-lubricating silicone rubber elastomer material in accordance with claim 16 .

20. A method of manufacturing a self-lubricating silicone elastomeric material, comprising mixing the components of the self-lubricating silicone elastomer composition in accordance with claim 1 and curing the composition.

Assignees

• Dow Silicones Corp

Inventors

• Wang Shaohui
• Chen Yusheng
• Wang Rui
• Wolf Hans Peter
• Fisher Mark D

Classifications

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L27/18

  Homopolymers or copolymers or tetrafluoroethene · CPC title

• C08K9/00

  Use of pretreated ingredients · CPC title

• C08K5/14

  Peroxides · CPC title