Thermoplastic thermally-conductive interface articles

Abstract

A thermoplastic, thermally-conductive composition is provided. The composition comprises a base thermoplastic elastomer matrix, thermally-conductive filler material, and temperature-activated phase change material. The composition can be used to make shaped, thermally-conductive articles. The articles can be used as thermal interfaces for dissipating heat from heat-generating devices such as electronic parts. The articles can have good electrical conductivity.

What is claimed is:  
     
         1 . A thermoplastic, thermally-conductive composition, comprising: a) about 20% to about 80% by weight of a thermoplastic elastomer matrix; b) about 20% to about 80% by weight of a thermally-conductive, filler material; and c) about 5 to about 50% by weight of a phase change material, said phase change material being capable of changing from a solid state to a liquid state and from a liquid state to a solid state within a temperature range of about 10° C. to about 115° C.  
     
     
         2 . The composition of  claim 1 , wherein the thermoplastic elastomer matrix comprises a material selected from the group consisting of styrenic copolymers, polyester copolymers, polyurethane copolymers, and polyamide copolymers.  
     
     
         3 . The composition of  claim 2 , wherein the thermoplastic elastomer matrix is a styrenic copolymer selected from the group consisting of styrene-butadiene-styrene, styrene-ethylene/butylene-styrene, styrene-isoprene-styrene, and styrene-ethylene/propylene-styrene.  
     
     
         4 . The composition of  claim 1 , wherein the thermoplastic elastomer matrix comprises a thermoplastic rubber.  
     
     
         5 . The composition of  claim 1 , wherein the thermally-conductive material is in the form of particles.  
     
     
         6 . The composition of  claim 5 , wherein the thermally-conductive filler material is a metal, metal oxide, ceramic, or carbon material.  
     
     
         7 . The composition of  claim 6 , wherein the thermally-conductive filler material is selected from the group consisting of aluminum, copper, magnesium, brass, alumina, magnesium oxide, silicon nitride, boron nitride, carbon black, and carbon graphite.  
     
     
         8 . The composition of  claim 1 , wherein the phase change material is a wax.  
     
     
         9 . The composition of  claim 8 , wherein the phase change material is selected from the group consisting of beeswax, paraffin wax, polyethylene glycol, polyethylene, polyhydric alcohols, and chlorinated naphthalene.  
     
     
         10 . The composition of  claim 1 , further comprising an additive selected from the group consisting of antioxidants, plasticizers, stabilizers, dispersing agents, coloring agents, tackifiers, mold-releasing agents, and adhesives.  
     
     
         11 . The composition of  claim 1 , wherein the composition has a thermal conductivity of greater than 3 W/m° K.  
     
     
         12 . An interface article suitable for use as an interface between a heat-generating device and a heat-dissipating device, comprising: a) about 20% to about 80% by weight of a thermoplastic elastomer matrix; b) about 20% to about 80% by weight of a thermally-conductive, filler material; and c) about 5 to about 50% by weight of a phase change material, said phase change material being capable of changing from a solid state to a liquid state and from a liquid state to a solid state within a temperature range of about 10° C. to about 115° C.  
     
     
         13 . The interface article of  claim 12 , wherein the article is in the form of a film.  
     
     
         14 . The interface article of  claim 12 , wherein the article is in the form of a pad.  
     
     
         15 . The interface article of  claim 12 , wherein the article has a thermal conductivity of greater than 3 W/m° K.  
     
     
         16 . The interface article of  claim 12 , wherein the article is electrically conductive and has a volume resistivity of 0.1 ohm-cm or lower and a surface resistivity of 1.0 ohm-cm or lower.  
     
     
         17 . A method of making a net-shape molded, thermoplastic, thermally-conductive interface article, comprising the steps of: 
 a) providing a molten composition comprising i) about 20% to about 80% by weight of a thermoplastic elastomer matrix; ii) about 20% to about 80% by weight of a thermally-conductive, filler material; and iii) about 5 to about 50% by weight of a phase change material, said phase change material being capable of changing from a solid state to a liquid state and from a liquid state to a solid state within a temperature range of about 10° C. to about 115° C.;    b) injecting the molten composition into a mold;    c) removing the composition from the mold to form a net-shape molded, thermoplastic, thermally-conductive interface article.    
     
     
         18 . The method of  claim 17 , wherein the interface article is a pad-like article, said article having recessed and non-recessed portions along its contour.  
     
     
         19 . The method of  claim 17 , wherein the interface article is a shielding gasket.  
     
     
         20 . The method of  claim 17 , wherein the interface article has a thermal conductivity of greater than 3 W/m° K.  
     
     
         21 . The method of  claim 17 , wherein the interface article is electrically conductive and has a volume resistivity of 0.1 ohm-cm or lower and a surface resistivity of 1.0 ohm-cm or lower.  
     
     
         22 . The method of  claim 17 , wherein the thermoplastic elastomer matrix of the composition comprises a material selected from the group consisting of styrenic copolymers, polyester copolymers, polyurethane copolymers, and polyamide copolymers.  
     
     
         23 . The method of  claim 17 , wherein the thermoplastic elastomer matrix of the composition comprises a thermoplastic rubber.  
     
     
         24 . The method of  claim 17 , wherein the thermally-conductive filler material of the composition is a metal, metal oxide, ceramic, or carbon material.  
     
     
         25 . The method of  claim 17 , wherein the thermally-conductive filler material of the composition is selected from the group consisting of aluminum, copper, magnesium, brass, alumina, magnesium oxide, silicon nitride, boron nitride, carbon black, and carbon graphite.  
     
     
         26 . The method of  claim 17 , wherein the phase change material of the composition is a wax.  
     
     
         27 . The method of  claim 17 , wherein the phase change material of the composition is selected from the group consisting of beeswax, paraffin wax, polyethylene glycol, polyethylene, polyhydric alcohols, and chlorinated naphthalene.