Thermally conductive substrate article

• US 10,568,233 B2
• Filed: 03/07/2013
• Issued: 02/18/2020
• Est. Priority Date: 06/28/2012
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Yang, Rui, Luo, Hui, Fisher, Carl E.
• Primary Examiner(s): Ewald, Maria V
• Assistant Examiner(s): Weydemeyer, Ethan
• Application Number:
  US14/391,459
• Publication Number:
  US 20150111021A1
• Time in Patent Office: 2,539 Days
• Field of Search: 29846-853, 174 681-268, 20419235-19236, 216 13- 21, 257E2306-E23077, 438238-256, 428220, 442164, 442378
• CPC Class Codes: B32B 15/14 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2250/40 Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
• CPC Class Codes: B32B 2260/021 Fibrous or filamentary layer
• CPC Class Codes: B32B 2260/046 Synthetic resin
• CPC Class Codes: B32B 2262/0238 Vinyl halide, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 2262/0253 Polyolefin fibres
• CPC Class Codes: B32B 2262/0261 Polyamide fibres
• CPC Class Codes: B32B 2262/0276 Polyester fibres
• CPC Class Codes: B32B 2264/105 Metal
• CPC Class Codes: B32B 2264/108 Carbon, e.g. graphite particles
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2307/306 Resistant to heat
• CPC Class Codes: B32B 2307/54 Yield strength; Tensile strength
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 2457/08 PCBs, i.e. printed circuit boards
• CPC Class Codes: B32B 27/38 comprising epoxy resins
• CPC Class Codes: B32B 5/022 Non-woven fabric
• CPC Class Codes: H01L 23/293 : Organic, e.g. plastic
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 7/20 : Modifications to facilitate cooling, ventilating, or heating
• CPC Class Codes: Y10T 442/2861 : Coated or impregnated synthetic organic fiber fabric
• CPC Class Codes: Y10T 442/656 : Preformed metallic film or foil or sheet [film or foil or sheet had structural integrity prior to association with the nonwoven fabric]

Abstract

A thermally conductive article including a polymeric layer comprising a nonwoven polymeric material. In particular, a flexible thermally conductive polymeric layer comprising an epoxy resin and a long-strand polymeric nonwoven material embedded in the epoxy resin. The polymeric nonwoven material may be heat stable at about 280 C.

Claims

1. An article comprising:

a flexible thermally conductive polymeric layer comprising an epoxy resin and a long-strand polymeric nonwoven material embedded in the epoxy resin, wherein the polymeric nonwoven material is heat stable at about 280°

C., and wherein the polymeric nonwoven material is a chemically etched polymeric nonwoven material having a density less than about 7 g/m².

2. The article of claim 1 being free standing.

3. The article of claim 1 having a thickness of less than about 50 μ

m.

4. The article of claim 1 having a thickness of about 15 to about 35 μ

m.

5. The article of claim 1 wherein the epoxy resin is loaded with one or both of thermally and electrically conductive particles.

6. The article of claim 5 wherein the thermally conductive particles have a thermal conductivity greater than 10 W/m·

K.

7. The article of claim 5 wherein the particles have a maximum dimension of about 0.5 to about 20 μ

m.

8. The article of claim 5 wherein the particles comprise up to about 75 wt % of the epoxy component.

9. The article of claim 1 wherein the nonwoven material is equal to or less than about 50 μ

m thick.

10. The article of claim 1 wherein the nonwoven material is equal to or less than about 30 μ

m thick.

11. The article of claim 1 wherein the nonwoven material is equal to or less than about 20 μ

m thick.

12. The article of claim 1 wherein the nonwoven material is about 10 micrometers to about 20 micrometers thick.

13. The article of claim 1 wherein the nonwoven material is selected from the group consisting of meltblown nonwovens, spunbond nonwovens, and electrospun nonwovens.

14. The article of claim 1 wherein the nonwoven material has a density less than about 3 g/m².

15. The article of claim 1 further comprising an electrically conductive layer on one or both sides of the polymeric layer.

16. The article of claim 15 wherein the conductive layers are selected from the group consisting of copper, aluminum and alloys thereof.

17. The article of claim 1 wherein the nonwoven material has a tensile strength of 10N or more in one direction.

18. The article of claim 1 which can be folded to 180°

forming a fold line and unfolded without cracking.

19. A method of making an article comprising a flexible thermally conductive layer, the method comprising:

providing a long-strand nonwoven material, the long-strand nonwoven material being heat stable at about 280°

C.;

chemically etching the long-strand nonwoven material in order to reduce a density of the long-strand nonwoven material and to thereby form an etched polymeric nonwoven material, the etched polymeric nonwoven material having a density less than about 7 g/m²;

embedding the etched polymeric nonwoven material in an epoxy resin; and

curing the epoxy resin to form the thermally conductive layer.

20. The method of claim 19, wherein the providing a long-strand nonwoven material step comprises:

forming a non-crosslinked nonwoven material; and

crosslinking the non-crosslinked nonwoven material to form the long-strand nonwoven material.