Device capable of thermally cooling while electrically insulating

Abstract

The present disclosure relates to a device for thermally cooling while electrically insulating. The device contains a first adhesive layer, polyimide substrate, a second adhesive layer and a heat sink. The first adhesive layer and the second adhesive layer are a vinyl or acrylic polymer. The polyimide substrate has at least two polyimide layers. The polyimide layers are derived from at least one aromatic dianhydride and at least one aromatic diamine. The adhesive layers and the polyimide layers may contain thermally conductive fillers, light absorbing pigments or mixtures of both.

1 . A device for thermally cooling while electrically insulating comprising:
 A. a first adhesive layer having a top surface and a bottom surface, the first adhesive layer bottom surface being directly bonded to a polyimide substrate, the first adhesive layer comprising an amount from 68 to 98 weight percent vinyl or acrylic polymer;   B. a polyimide substrate comprising at least a first polyimide layer and a second polyimide layer wherein:
 i. the first polyimide layer and the second polyimide layer are directly bonded to each other; the first polyimide layer and the second polyimide layer are the same or different, and provide thermal conduction and electrical insulation properties, 
 ii. the first polyimide layer and the second polyimide layer each comprise an amount from 40 to 90 weight percent polyimide, the polyimide being derived from at least one aromatic dianhydride and at least one aromatic diamine, the aromatic diamine being at least 80 mole percent of the total moles of diamine incorporated into the polyimide and the aromatic dianhydride being at least 80 mole percent of the total moles of dianhydride incorporated into the polyimide, and 
 iii. the first polyimide layer and the second polyimide layer each further comprise 10 to 50 weight percent thermally conductive filler, and 0 to 20 weight percent light absorbing pigment; 
   C. a second adhesive layer having a top surface and a bottom surface, the second adhesive layer top surface being directly bonded to the polyimide substrate; the second adhesive layer comprising an amount from 68 to 98 weight percent vinyl or acrylic polymer;   D. a metal heat sink having a top surface and a bottom surface, the heat sink top surface being directly bonded to the second adhesive layer bottom surface.   
   
   
       2 . A device in accordance with  claim 1 , wherein the first adhesive layer and the second adhesive layer additionally comprise a filler selected from thermally conductive filler, light absorbing pigment and mixtures thereof. 
   
   
       3 . A device in accordance with  claim 1  or  2 , wherein the first adhesive layer and second adhesive layers are selected from a group consisting of:
 ethylene vinyl acetate copolymer with adhesion promotor,   ethylene vinyl acetate glycidyl acrylate terpolymer,   ethylene vinyl acetate glycidyl methacrylate terpolymer,   ethylene alkyl acrylate copolymers with adhesion promotor,   ethylene alkyl methacrylate copolymers with adhesion promotor,   ethylene glycidyl acrylate,   ethylene glycidyl methacrylate,   ethylene alkyl acrylate glycidyl acrylate terpolymer,   ethylene alkyl methacrylate glycidyl acrylate terpolymer,   ethylene alkyl acrylate maleic anhydride terpolymers,   ethylene alkyl methacrylate maleic anhydride terpolymers   ethylene alkyl acrylate glycidyl methacrylate terpolymers,   ethylene alkyl methacrylate glycidyl methacrylate terpolymers,   alkyl acrylate acrylonitrile acrylic acid terpolymers,   alkyl acrylate acrylonitrile methacrylic acid terpolymers,   ethylene acrylic acid copolymer including salts thereof,   ethylene methacrylic acid copolymer including salts thereof,   alkyl acrylate acrylonitrile glycidyl methacrylate terpolymers,   alkyl methacrylate acrylonitrile glycidyl methacrylate terpolymers,   alkyl acrylate acrylonitrile glycidyl acrylate terpolymers,   alkyl methacrylate acrylonitrile glycidyl acrylate terpolymers, polyvinyl butyral,   ethylene alkyl acrylate methacrylic acid terpolymers including salts thereof,   ethylene alkyl methacrylate methacrylic acid terpolymers including salts thereof,   ethylene alkyl acrylate acrylic acid terpolymers including salts thereof   mixtures thereof,   ethylene alkyl methacrylate acrylic acid terpolymers including salts thereof,   ethylene ethyl hydrogen maleate,   ethylene alkyl acrylate ethyl hydrogen maleate,   ethylene alkyl methacrylate ethyl hydrogen maleate, and mixtures thereof.   
   
   
       4 . A device in accordance with  claim 1 , wherein the polyimide substrate additionally comprises at least one fluoropolymer adhesive layer having a top layer and a bottom layer wherein the fluoropolymer adhesive top layer is attached to the first polyimide layer and the fluoropolymer adhesive bottom layer is attached to the second polyimide layer. 
   
   
       5 . A device in accordance with  claim 4 , wherein the fluoropolymer adhesive layer is selected from tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene perfluoroalkoxy copolymer, tetrafluoroethylene ethylene copolymer, polyvinyl fluoride and mixtures thereof. 
   
   
       6 . A device in accordance with  claim 4 , wherein the fluoropolymer adhesive layer additionally comprises a thermally conductive filler. 
   
   
       7 . A device in accordance with  claim 4 , wherein the polyimide substrate first polyimide layer and second polyimide layer comprise two or more polyimide layers. 
   
   
       8 . A device in accordance with  claim 1 , wherein the aromatic dianhydride is selected from a group consisting of pyromellitic dianhydride, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, 3,3′,4,4′-diphenyl sulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)1,1,1,3,3,3-hexafluoropropane dianhydride and mixtures thereof; and wherein the aromatic diamine is selected from a group consisting of 3,4′-diaminodiphenyl ether, 1,3-bis-(4-aminophenoxy)benzene, 4,4′-diaminodiphenyl ether, 1,4-diaminobenzene, 1,3-diaminobenzene and mixtures thereof. 
   
   
       9 . A device in accordance with  claims 1 ,  2  or  6  wherein the thermally conductive filler is selected from a group consisting of aluminum oxide, boron nitride coated aluminum oxide, granular aluminum oxide, fumed aluminum oxide, silicon dioxide, granular silicon dioxide, fumed silicon dioxide, silicon carbide, aluminum nitride, aluminum oxide coated aluminum nitride, silicon dioxide coated aluminum nitride, titanium dioxide, boron nitride, cubic boron nitride, hexagonal boron nitride, diamond, beryllium oxide, talc, zinc oxide and mixtures thereof. 
   
   
       10 . A device in accordance with  claims 1  or  2 , wherein the light absorbing pigment is selected from a group consisting of carbon black, titanium dioxide, benzotriazoles, benzophenones, hindered amines and mixtures thereof. 
   
   
       11 . A device in accordance with  claim 1  wherein the first adhesive layer and the second adhesive layer thickness are each from 6.25 to 75 microns. 
   
   
       12 . A device in accordance with  claim 1  wherein the polyimide substrate thickness is from 8 to 150 microns. 
   
   
       13 . A device in accordance with  claim 1  wherein the polyimide substrate thickness is from 12.5 to 125 microns. 
   
   
       14 . A device in accordance with  claim 4  wherein the fluoropolymer adhesive layer thickness is from 1.25 to 12.5 microns. 
   
   
       15 . A device in accordance with  claim 1  further comprising photovoltaic cell directly bonded to the first adhesive layer top surface. 
   
   
       16 . A device for thermally cooling while electrically insulating comprising:
 A. a first adhesive layer having a top surface and a bottom surface, the first adhesive layer bottom surface being directly bonded to a polyimide substrate, the first adhesive layer comprising an amount from 68 to 98 weight percent vinyl or acrylic polymer;   B. a polyimide substrate comprising at least a first polyimide layer and a second polyimide layer wherein:
 i. the first polyimide layer and the second polyimide layer are directly bonded to each other; the first polyimide layer and the second polyimide layer are the same or different, and provide thermal conduction and electrical insulation properties, 
 ii. the first polyimide layer and the second polyimide layer each comprise an amount from 40 to 90 weight percent polyimide, the polyimide being derived from at least one aromatic dianhydride and at least one aromatic diamine, the aromatic diamine being at least 50 mole percent of the total moles of diamine incorporated into the polyimide and the aromatic dianhydride being at least 50 mole percent of the total moles of dianhydride incorporated into the polyimide, and 
 iii. the first polyimide layer and the second polyimide layer each further comprise 5 to 50 weight percent thermally conductive filler, and 0 to 20 weight percent light absorbing pigment; 
   C. a second adhesive layer having a top surface and a bottom surface, the second adhesive layer top surface being directly bonded to the polyimide substrate; the second adhesive layer comprising an amount from 68 to 98 weight percent vinyl or acrylic polymer;   D. a metal heat sink having a top surface and a bottom surface, the heat sink top surface being directly bonded to the second adhesive layer bottom surface.