Multilayer composite thermal conductive film and preparation method thereof

Abstract

The invention relates to a multilayer composite thermal conductive film and a preparation method thereof. The middle layer of the thermal conductive film is a nano-cellulose film. The upper and lowersurfaces of the nano-cellulose film are orderly coated with a nano-cellulose/graphene film layer and/or a nano-cellulose/boron nitride film layer. The layers are connected through hydrogen bonding between cellulose matrixes to form composite thermal conductive films with an ABA three-layer structure and an ACBCA five-layer structure. Each layer of the film has the mass of 15-30mg. The nano-cellulose/graphene film layer has graphene content of 6-10wt% and boron nitride content of 6-10wt%. The boron nitride and graphene have high thermal conductivity. The multilayer composite thermal conductivefilm has high thermal conductivity. Through the core toughening and the multilayer bionic structure of the middle cellulose layer, the excellent mechanical properties are obtained. The mixed layer ofboron nitride and cellulose is used as an outer layer so that the film has good electrical insulating properties. The multilayer composite thermal conductive film solves the heat dissipation problemsof the modern electronic device and can be used in a thermal conduction and heat dissipation device.

Description

technical field [0001] The invention relates to a composite heat-conducting film and a preparation method thereof, in particular to a multilayer composite heat-conduction film and a preparation method thereof. Background technique [0002] With the development of more and more sophisticated electronic instruments, effective heat dissipation has become the key to the normal operation of electronic products. It is becoming more and more important to improve the thermal conductivity of packaging materials. At present, the main component of packaging materials is plastic, but The thermal conductivity of plastic is low (0.1~0.5 W·m −1 • K −1 ), which cannot meet the heat dissipation requirements of special electronic devices. [0003] Graphene has high thermal conductivity, with a thermal conductivity as high as 5300 W·m −1 • K −1 (The thermal conductivity is 10 times that of copper) and has good mechanical properties, hexagonal boron nitride also has high thermal conductivit...

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Problems solved by technology

[0005] In recent years, in the research on thermally conductive cellulose films at home and abroad, such as Chinese patent (201610315269.8), a flexible nanocellulose-graphene composite film and its preparation method, the nanocellulose-graphene composite film was prepared by suction filtration. Film, because the filler is graphene with high conductivity, it cannot be applied in the field of thermal conductivity and insulation; Chinese patent (201710111293.4) ​​transparent insulating graphene composite thermal conductivity film and its preparation method, prepared by layer-by-layer leaching self-assembly method Multi-layer cellulose composite heat-conducting film, the operation process is cumbersome, the working time is long, and the various organic reducing agents used in the above two patents, such as hydrazine hydrate, sodium borohydride, hydroiodic acid, urea solution, etc., are likely to pollute the environment ; Chinese patent (201710441920.0) used up to 20wt% hexagonal boron nitride as a filler in a preparation method of a high thermal conductivity nanocellulose-based electrical insulation composite film, but the thermal conductivity was only 115.8% higher than that of the matrix nanocellulose. Insufficient capacity to meet high demand

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