▎ 摘　　要

NOVELTY - Dual heat conduction network polyurethane heat conduction composite material constructed by two-step method comprises thermoplastic polyurethane material as the matrix, heat-conducting filler A to construct heat-conducting network 1 in the porous polymer skeleton based on an in-situ foaming polymerization process, and heat-conducting filler B adsorbed on the three-dimensional porous framework of the polymer to form a thermally conductive network 2. The thermally conductive filler A is sheet-shaped thermally conductive filler, and/or whisker-shaped thermally conductive filler. The thermally conductive filler B is granular thermally conductive filler, sheet-shaped thermally conductive filler, and/or whisker-shaped thermally conductive filler. USE - Dual heat conduction network polyurethane heat conduction composite material constructed by two-step method. ADVANTAGE - The method utilizes a two-step preparation process to regulate two different heat-conducting fillers to successfully construct a uniform and orderly dual thermally conductive path in the polymer matrix, compared with the traditional simple mixing and filling of two kinds of fillers to prepare heat-conducting composite materials, can more finely regulate the uniform distribution of heat-conducting fillers, building efficient heat-conducting paths, and significantly improves the heat-conducting properties of polymer materials, has simple process, is easy to realize large-scale production, and has important industrialization potential. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for preparing composite material, comprising (i) uniformly blending the raw material of polyurethane foaming white material with heat-conducting filler A to mix the heat-conducting filler, adding black material and uniformly stirring, and in-situ polymerize and foaming at room temperature to prepare heat-conducting filler A/polyurethane with three-dimensional porous skeleton structure foamed composite materials, and heat-conducting fillers to form continuous heat-conducting network within the polymer matrix 1, (ii) dispersing the heat-conducting filler B in the ethanol solution, immersing the polyurethane foam in the solution, accelerating the uniform passage of the dispersion through suction filtration, and circulating 5-10 times, taking out the impregnated foam and drying the solution on its surface, and placing in a blast drying oven for 60-120 minutes for drying treatment, uniformly adsorbing heat-conducting filler B in the three-dimensional skeleton of the heat-conducting filler A/polyurethane foam composite material forming a three-dimensional heat conduction network 2, and (iii) subjecting polymer foam to high-temperature thermo-compression molding at 175℃ and 10 MPa.