Thermal Switch Based on Polymer Compound
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Accused Products
Abstract
The present invention relates to an article suitable to act as a thermal switch device, the article having a surface resistance of more than 105 ohms and formed from a polymer composition comprising from 50 to 99.9 wt % relative to the total weight of the polymer composition, of a polymer being selected from an amorphous polymer having a glass transition temperature Tg, a semi-crystalline polymer having a melting temperature Tm or a mixture thereof, and from 0.1 to 50 wt % relative to the total weight of the polymer composition, of a conductive material, wherein the surface resistance of the article is divided by at least 10, preferably by at least 100, when said article is submitted for a determined period of time of less than 5 minutes to a temperature of switch i) ranging from Tg+10° C. to Tg+250° C. if the polymer composition comprises an amorphous polymer, or ii) ranging from Tm−80° C. to Tm+250° C. if the polymer composition comprises a semi-crystalline polymer.
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27 Claims
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1-14. -14. (canceled)
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15. An article suitable to act as a thermal switch device, the article having a surface resistance of more than 105 ohms as determined according to ASTM D257-07, and being formed from a polymer composition, said polymer composition comprising
from 50 to 99.9 wt % relative to the total weight of the polymer composition, of a polymer being selected from an amorphous polymer having a glass transition temperature Tg, a semi-crystalline polymer having a melting temperature Tm or a mixture thereof, and from 0.1 to 50 wt % relative to the total weight of the polymer composition, of a conductive material; wherein the surface resistance of the article is divided by at least 10, when said article is submitted for a determined period of time of less than 5 minutes to a temperature of switch i) ranging from Tg+10°
C. to Tg+250°
C. if the polymer composition comprises an amorphous polymer, orii) ranging from Tm−
80°
C. to Tm+250°
C. if the polymer composition comprises a semi-crystalline polymer.- View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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20. The article according to claim 19 wherein the surface resistance of the article is divided by at least 10, when said article is submitted for less than 2 minutes to the temperature of switch.
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21. The article according to claim 15, wherein the polymer composition comprises at least 0.5 wt % relative to the total weight of the polymer composition, of the conductive material.
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22. The article according to claim 15 having a thermal conductivity higher than 0.4 W/(m*K).
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23. The article according to claim 15, wherein the article is a film, a sheet, a formed sheet, a pipe or an injected article.
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24. A process to produce an article suitable to act as a thermal switch device according to claim 15, comprising the step of:
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a) providing a polymer composition having a surface resistance of less than 104 ohms, said polymer composition comprising; from 50 to 99.9 wt % relative to the total weight of the polymer composition, of a polymer being selected from an amorphous polymer having a glass transition temperature Tg, a semi-crystalline polymer having a melting temperature Tm or a mixture thereof, and from 0.1 to 50 wt % relative to the total weight of the polymer composition, of a conductive material; b) forming or pre-forming an article; and c) cooling the article by contact with a cooling device system or medium using a temperature of at least Tg−
20°
C. if the polymer composition comprises an amorphous polymer or at least Tm−
20°
C. if the polymer composition comprises a semi-crystalline polymer.
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25. A process according to claim 24, wherein the step b) of forming or performing the article is made by extrusion or injection.
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26. A process according to claim 24, wherein the step c) comprises cooling the article by a cooling device system using a temperature ranging from Tg−
- 20°
C. to Tg−
150°
C. if the polymer composition comprises an amorphous polymer or ranging from Tm−
20°
C. to Tm−
150°
C. if the polymer composition comprises a semi-crystalline polymer.
- 20°
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27. A process according to claim 24, the process comprising a step b) of pre-forming the article resulting in a pre-formed article wherein the process further comprises after step c), a step d) of forming the article from the preformed article at a temperature less than Tg when the polymer composition comprises an amorphous polymer or less than Tm when the polymer composition comprises a semi-crystalline polymer.
Specification