Rubber composition based on a silicone elastomer and on a PCM, process for the preparation thereof, flexible element and thermal control/regulating system incorporating same

Patent metadata

Field	Value
Publication number	US-9676941-B2
Application number	US-201313940542-A
Country	US
Kind code	B2
Filing date	Jul 12, 2013
Priority date	Jul 25, 2012
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A crosslinked rubber composition, process for preparing same, and a flexible component based on at least one room-temperature vulcanizing “RTV” silicone elastomer and including at least one phase change material (PCM) is provided. The flexible element includes at least one elastomer layer capable of storing thermal energy and of releasing it which includes the crosslinked rubber composition. Also provided is a thermal control or regulating system incorporating the flexible element. The composition is such that the silicone elastomer has a viscosity measured at 23° C. according to the ISO 3219 standard which is less than or equal to 5000 mPa·s. The silicone elastomer includes two components A and B and is crosslinked by polyaddition or polycondensation, and the composition includes the PCM, which is not encapsulated and is in the micronized state, in an amount of greater than 50 phr (phr: parts by weight per hundred parts per elastomer(s)).

First claim

The invention claimed is:

1. A crosslinked rubber composition comprising a crosslinked mixture of:
at least one room-temperature vulcanizing “RTV” silicone elastomer having a viscosity measured at 23° C. according to the ISO 3219 standard which is less than or equal to 5000 mPa·s, and
at least one phase change material (PCM),
wherein said rubber composition furthermore comprises between 150 phr and 200 phr of at least one thermally conductive filler selected from the group consisting of metals, metal oxides, nitrides, carbon-based materials and mixtures thereof.

2. The composition as claimed in claim 1 , wherein said at least one silicone elastomer has a viscosity measured at 23° C. according to the ISO 3219 standard which is less than or equal to 4000 mPa·s.

3. The composition as claimed in claim 1 , wherein said at least one silicone elastomer has a viscosity measured at 23° C. according to the ISO 3219 standard which is less than or equal to 1000 mPa·s.

4. The composition as claimed in claim 1 , wherein said at least one PCM is not encapsulated and is in a micronized and dispersed state in the composition, in an amount of greater than 50 phr (phr: parts by weight per hundred parts of elastomer(s)).

5. The composition as claimed in claim 4 , wherein said at least one PCM is present in the composition in an amount inclusively between 100 phr and 300 phr and comprises a fatty acid.

6. The composition as claimed in claim 4 , wherein the composition has a change of state enthalpy per unit mass ΔH of greater than 70 J/g.

7. The composition as claimed in claim 4 , wherein the composition has a change of state enthalpy per unit mass ΔH between 80 J/g and 200 J/g.

8. The composition as claimed in claim 1 , wherein the composition has a thermal conductivity of greater than 0.2 W·m −1 K −1 .

9. The composition as claimed in claim 1 , wherein the composition has a thermal conductivity of greater than 1 W·m −1 K −1 .

10. The composition as claimed in claim 1 , wherein said at least one thermally conductive filler is selected from the group consisting of copper, aluminum, silver, zinc oxide, boron nitride, aluminum nitride, silver nitride, graphite, graphene, carbon nanotubes, and mixtures thereof.

11. The composition as claimed in claim 1 , wherein said at least one silicone elastomer is of the type having two components A and B, A being a silicone and B being a curing or vulcanizing agent, and wherein said at least one silicone elastomer is crosslinked by polyaddition or polycondensation.

12. The composition as claimed in claim 11 , wherein said at least one silicone elastomer is crosslinked by polyaddition and comprises a platinum-based catalyst.

13. The composition as claimed in claim 1 , wherein said at least one silicone elastomer has a density measured at 23° C. according to the ISO 2781 standard which is less than 1.1 g/cm 3 .

14. The composition as claimed in claim 1 , wherein said at least one PCM has at least one melting point above 50° C.

15. A process for preparing a crosslinked rubber composition comprising the following steps:
a) room-temperature mixing, in a liquid state, of:
A) a component A which is a silicone, and
B) a component B which is a curing or vulcanizing agent, said components A and B being two components of an at least one room-temperature vulcanizing “RTV” silicone elastomer having a viscosity measured at 23° C. according to the ISO 3219 standard which is less than or equal to 5000 mPa·s,
C) and of at least one powdered PCM, and
D) at least one thermally conductive filler in an amount inclusively between 150 phr and 200 phr selected from the group consisting of metals, metal oxides, nitrides, carbon-based materials and mixtures thereof, and

b) crosslinking also at room temperature of the mixture obtained in step a) by polyaddition or polycondensation.

16. The process as claimed in claim 15 , wherein said mixing is carried out in a blade mixer in order to obtain the crosslinkable liquid mixture wherein said at least one PCM is dispersed in the micronized state, in that this liquid mixture is poured into a mold and in that this mixture is crosslinked in this mold.

17. A tubular or sheet-shaped flexible element which comprises at least one elastomer layer capable of storing thermal energy and of restoring it, wherein said at least one layer consists of a crosslinked rubber composition as claimed in claim 1 having a Shore A hardness between 20 and 90.

18. A thermal control or regulating system wherein the system incorporates at least one flexible element as claimed in claim 17 .

19. The composition as claimed in claim 1 wherein said at least one silicone elastomer has a viscosity measured at 23° C. according to ISO 3219 standard which is less than or equal to 1000 mPa·s.

20. The composition as claimed in claim 5 wherein said fatty acid is stearic acid.

21. The composition as claimed in claim 14 wherein said at least one PCM as at least one melting point above 80° C.

22. The process as claimed in claim 15 wherein the at least one thermally conductive material is selected from the group consisting of copper, aluminum, silver, zinc oxide, boron nitride, aluminum nitride, silver nitride, graphite, graphene, carbon nanotubes, and mixtures thereof.

23. A thermal control or regulating system according to claim 18 that is used for warming submerged pipelines which are submarine pipelines comporting a fluid.

24. A thermal control of regulating system according to claim 23 wherein said fluid is an oil or petroleum.

25. The composition as claimed in claim 14 , wherein said at least one PCM has at least one melting point above 80° C.

26. The thermal control or regulating system of claim 18 that is used for air conditioning of a building, for warming a passenger compartment or engine of a motor vehicle, aircraft or spacecraft, for the thermal regulation of a battery, or for warming submerged pipelines.

Assignees

• Hutchinson

Inventors

• Van Eibergen Arthur
• Swoboda Benjamin
• Le Rossignol Benoit
• Dominiak Christophe

Classifications

• Y02E60/145

  Cross-Sectional Technologies · mapped topic

• C08L83/04 Primary

  Polysiloxanes · CPC title

• C08K3/08

  Metals · CPC title

• F16L11/04

  made of rubber or flexible plastics · CPC title

• Y10T428/1386

  Natural or synthetic rubber or rubber-like compound containing · CPC title