Process for treating silica-filled polyamide by impregnation in supercritical CO2

Patent metadata

Field	Value
Publication number	US-10487186-B2
Application number	US-201716345346-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Oct 27, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The present invention relates to a process for treating a polyamide-based material comprising silica fibers and/or fillers, by impregnation with at least one hydrophobic additive in supercritical CO 2 .
The invention also relates to a polyamide-based material comprising silica fibers and/or fillers and impregnated with at least one hydrophobic additive, obtained via such a process, and to the use thereof as an electrically insulating component in an electrical device, in particular in a circuit breaker.

First claim

The invention claimed is:

1. A process for treating a polyamide-based material comprising silica fibers and/or fillers, the process comprising impregnating the polyamide-based material with at least one hydrophobic additive in supercritical CO 2 .

2. The process of claim 1 , comprising reducing water uptake of said material.

3. The process of claim 1 , wherein the material is comprises polyamide 6,6 or on polyphthalamide filled with silica fibers and/or fillers.

4. The process of claim 1 , wherein the material comprises silica fibers and/or fillers, in a mass proportion of greater than or equal to 20% of the total mass of the material.

5. The process of claim 1 , wherein said material forms all or part of an electrically insulating component.

6. The process of claim 1 , wherein the hydrophobic additive is chosen from dielectric silicone oils which are soluble in supercritical CO 2 and hydrophobic fluoro compounds which are soluble in supercritical CO 2 .

7. The process of claim 6 , wherein the dielectric silicone oil is chosen from linear silicone oils of polydimethylsiloxane type and aromatic silicone oils.

8. The process of claim 6 , wherein the hydrophobic fluoro compounds which are soluble in supercritical CO 2 comprise at least one at least partially fluorinated hydrophobic hydrocarbon-based chain, including at least 6 carbon atoms.

9. The process of claim 8 , wherein said hydrophobic fluoro compound comprises, besides at least said hydrophobic hydrocarbon-based chain, at least one group which is capable of interacting via hydrogen bonding or via Van der Waals interaction with the polyamide chains.

10. The process of claim 1 , wherein said hydrophobic additive is used in an amount of between 0.2% and 5% by weight relative to the weight of the polyamide-based material.

11. The process of claim 1 , comprising:
placing a polyamide-based material filled with silica fibers and/or fillers and at least one hydrophobic additive in an autoclave;
generating supercritical carbon dioxide in the autoclave;
keeping the material in the autoclave in the presence of the supercritical CO 2 and of the hydrophobic additive so as to ensure the impregnation of the material with said hydrophobic additive;
recovering the impregnated material by depressurization of the autoclave; and
optionally, drying the material thus impregnated.

12. The process of claim 1 , wherein the impregnation treatment in supercritical CO 2 is performed at a temperature of between 50° C. and 150° C.

13. The process of claim 1 , wherein the impregnation treatment in supercritical CO 2 is performed at a pressure of between 80 and 450 bar.

14. The process of claim 1 , wherein the duration of the impregnation treatment in supercritical CO 2 is between 30 and 180 minutes.

15. A polyamide-based material comprising silica fibers and/or fillers and impregnated with at least one hydrophobic additive, obtained via a process of claim 1 .

16. The material of claim 15 , said material being impregnated with said hydrophobic additive to a thickness extending from the surface of the material down to a depth of at least 200 μm.

17. The material of claim 15 , comprising a mass content of said hydrophobic additive of between 0.2% and 5%, relative to the total weight of the material.

18. An electrically insulating component totally or partly formed from a polyamide-based material comprising silica fibers and/or fillers and impregnated with at least one hydrophobic additive, obtained via a process of claim 1 .

19. An electrical device comprising at least one electrically insulating component of claim 18 .

20. The electrical device of claim 19 , said device comprising a sealing enclosure in which are found, besides said electrically insulating component, electrical components and a gaseous medium which ensure the electrical insulation and the extinction of electric arcs that are liable to form in this sealing enclosure.

21. The electrical device of claim 19 , said device being a medium-voltage or low-voltage electrical device.

Assignees

• Commissariat Energie Atomique

Inventors

• Poncelet Olivier
• Getto Daniel

Classifications

• C08J7/0427

  with only one layer of a composition containing a polymer binder (with more layers C08J7/042) · CPC title

• H01H2033/566

  Avoiding the use of SF6 · CPC title

• H01H33/021

  Use of solid insulating compounds resistant to the contacting fluid dielectrics and their decomposition products, e.g. to SF6 · CPC title

• H01B3/46

  silicones · CPC title

• H01B3/445

  from vinylfluorides or other fluoroethylenic compounds · CPC title