A kind of heat transmission graphene composite film and preparation method thereof
Technical field
The invention belongs to thermally conductive material technical field, be specifically related to a kind of heat transmission graphene composite film and preparation method thereof.
Background technology
Along with electronic product is increasingly intelligent and complicated, the required component number of its interiors of products increases, and integrated level uprises.And the heat that the direct impact that this situation is brought is electronic product to produce in operational process is increasing.If these heats are discharged not in time, be easy to run-up and form high temperature.The generation of high temperature will reduce performance, reliability and the work-ing life of these electronic products greatly.So electronic product industry is more and more higher to the requirement of the heat sink material as heat control system core component, not only require heat sink material to there is efficient heat dispersion, also must possess the feature that quality is light, material is thin, snappiness is good simultaneously.
In current electronic product, widely used heat dissipation film material mainly contains natural stone ink film and electrographite film.
Natural graphite film preparation complex process, difficult forming, the heat dissipation film snappiness of preparing is poor, and thickness is thicker, can not meet well the design requirements of electronic product.For natural stone ink film, Chinese patent application CN102730675A discloses a kind of high conductive graphite film and preparation method thereof, this technology is by mixing a certain proportion of natural graphite and composite oxidant, and by series reaction, finally calendering sample charing and greying in blocks prepared to natural stone ink film.Although this product has good thermal conductivity, but the film of preparing thicker (at least reaching 100 μ m) and snappiness are poor, thicker heat dissipation film material occupies too many space in electronic product, directly affect the project organization of product, at electronic product, day by day do under thin prerequisite, the share of market of natural stone ink film will be more and more lower.
The selling at exorbitant prices of electrographite film is mainly because its manufacturing cost is too high.The rising that electrographite film mold temperature is too high and the long highly energy-consuming causing of molding time has brought manufacturing cost in preparation process, this kind of technical matters can not meet the requirement of the national energy-saving reduction of discharging becoming more and more important.For electrographite film, the disclosed graphite film of Chinese patent application CN103080005A and manufacture method thereof, this technology prepares electrographite film by high temperature carbonization and high temperature graphitization Kapton, this heat dissipation film material thickness can design, the thinnest 5 μ m that reach of film, and radiating effect is very good, and density is less, can meet well the frivolous requirement of electronic product, but the manufacturing cost of this kind of electrographite film is too high, easily the thousands of units of every square meter.Manufacturing cost height is mainly because a large amount of power consumptions in charing and graphitizing process cause.In this preparation method, carbonization temperature is up to 1500 ℃, and graphitization temperature is up to 3000 ℃, and this certainly will bring highly energy-consuming and expensive, causes holding at high price of heat dissipation film material.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of heat transmission graphene composite film, to overcome the thicker product shortcoming that causes meeting design of electronic products requirement and the selling at exorbitant prices that electrographite film preparation temperature is higher, power consumption seriously causes of natural graphite film thickness of current use; The present invention also provides a kind of method of preparing above-mentioned heat transmission graphene composite film.
In order to realize above-mentioned object, contriver is by charing and graphited layer high molecule film are not innovated formula precoating Graphene coating, guaranteeing that the heat dissipation film material of preparing greatly reduces material charing and graphited temperature and time in frivolous, reduced manufacturing cost, and made to be added in heat dissipation film material high-new nano material Graphene by this kind of preparation method.
Basic conception of the present invention is that macromolecule membrane is graphene coated in advance, makes to be on the one hand added to Graphene in the mould material of last moulding and forms the graphene composite material with nanostructure; Be coated on the other hand surperficial Graphene and can strengthen macromolecule membrane charing and graphited ability in heat treatment process.Consideration based on this two aspect, reduces charing and graphited temperature and time on the one hand, makes full use of on the other hand Graphene high thermal conductivity coefficient and high-flexibility, makes final heat dissipation film material have good marketable value.
Concrete, the preparation method of heat transmission graphene composite film provided by the invention, comprises the following steps:
(1) prepare the macromolecule membrane of some fixed thickness, respectively Graphene slurry is evenly coated on to the surface of each macromolecule membrane;
(2) put into baking oven after applying the complete stacked placement of macromolecule membrane, more than toasting 1h at 60~80 ℃, form duplexer;
(3) duplexer having toasted is put into charring furnace, in argon gas or nitrogen atmosphere, more than charing 1h at 700~1000 ℃;
(4) duplexer after charing is put into graphitizing furnace, in argon gas or nitrogen atmosphere, more than greying 1h, obtain graphene composite film at 1800~2500 ℃.
Preferably, the water-based that described Graphene slurry is Graphene or solvent-borne type slurry, pH value is 6.3~7.8.
Further, described Graphene specific surface area is 150~300m
2/ g.
Further, described Graphene mean thickness is 3~5nm.
Preferably, on each macromolecule membrane, the method for graphene coated slurry is coating, brushing, spraying or dipping.
Preferably, to carry out the stacked number of plies be 10~200 layers to described macromolecule membrane.
Further, every floor height molecular film thickness is 15~30 μ m.
Further, the Graphene slurry thickness applying on every floor height molecular film is 10~20 μ m.
Preferably, described macromolecule membrane is polyimide film (PI), polyoxadiazole film (POD) or polyacrylonitrile film (PAN).
The present invention also provides a kind of heat transmission graphene composite film preparing by aforesaid method.
The present invention passes through in advance at the graphene coated slurry of layer high molecule film surface, and by the stacked placement of coated macromolecule membrane, make full use of the induced nucleation effect that Graphene plays in macromolecule membrane charing and graphitizing process, charing and graphited time and temperature are reduced greatly, and the graphene composite film material preparing still has higher thermal conductivity, good snappiness and excellent machining property.The heat transmission graphene composite film material of preparing by this technology is compared with similar graphite film heat sink material on market, its preparation temperature is lower, molding time very fast, power consumption is lower, and can be advantageously applied in electron device, LED light fixture and the liquid-crystal display screen products of golf calorific value, to existing film heat sink material, have substituting preferably.
Embodiment
Below in conjunction with embodiment, further set forth the present invention.
Embodiment 1
(1) prepare 20 polyimide (PI) film, every PI film thickness is between 20 μ m; Prepare sufficient solvent-borne type Graphene slurry, this slurry pH value is 6.5, and Graphene specific surface area is 200m
2/ g, Graphene mean thickness is 5nm.
(2) Graphene coating is carried out in every Kapton surface, guarantee to apply evenly.The Graphene thickness applying is between 15 μ m.
(3) the PI film-stack that is painted with in advance Graphene is placed, form duplexer.
(4) duplexer is put into baking oven and toast, storing temperature is 80 ℃, and baking time is 1h.After solvent-borne type Graphene coating Drying and cooling, duplexer can take out.
(5) duplexer after baking is placed in charring furnace, and fixes with graphite cake fixture, and duplexer is imposed to certain pressure, carbonization temperature is made as 700 ℃, and carbonization time 4h passes into argon gas as protection gas during charing.
(6) film after charing is placed on to graphitizing furnace, as described in (5), still with graphite block, pushes down film, and carry out graphitization processing, wherein the temperature of graphitization processing is 1800 ℃, and graphitization time 5h passes into argon gas as protection gas during greying.
(7) the graphene composite film material finally preparing is tested according to testing standard ASTM E1461-01, the thermal conductivity that test obtains is 1000W/mK.
Embodiment 2
(1) prepare 20 polyimide (PI) film, every PI film thickness is 20 μ m; Prepare sufficient solvent-borne type Graphene slurry, this slurry pH value is 6.5, and Graphene specific surface area is 200m
2/ g, Graphene mean thickness is 5nm.
(2) Graphene coating is carried out in every Kapton surface, guarantee to apply evenly.The Graphene thickness applying is between 15 μ m.
(3) the PI film-stack that is painted with in advance Graphene is placed, form duplexer.
(4) duplexer is put into baking oven and toast, storing temperature is 80 ℃, and baking time is 1h.After solvent-borne type Graphene coating Drying and cooling, duplexer can take out.
(5) duplexer after baking is placed in charring furnace, and fixes with graphite cake fixture, and duplexer is imposed to certain pressure, carbonization temperature is made as 1000 ℃, and carbonization time 4h passes into argon gas as protection gas during charing.
(6) film after charing is placed on to graphitizing furnace, as described in (5), still with graphite block, pushes down film, and carry out graphitization processing, wherein the temperature of graphitization processing is 2500 ℃, and graphitization time 5h passes into argon gas as protection gas during greying.
(7) the graphene composite film material finally preparing is tested according to testing standard ASTM E1461-01, the thermal conductivity that test obtains is 1900W/mK.
Embodiment 3
(1) prepare 20 polyimide (PI) film.
(2) Graphene coating is not carried out on Kapton surface, and directly by its stacked placement.
(3) stacked good PI film is placed in charring furnace, and fixes with graphite cake fixture, and duplexer is imposed to certain pressure, carbonization temperature is made as 1500 ℃, and carbonization time 7h passes into argon gas as protection gas during charing.
(4) film after charing is placed on to graphitizing furnace, as described in (3), still with graphite block, pushes down film, and carry out graphitization processing, wherein the temperature of graphitization processing is 3000 ℃, and graphitization time 10h passes into argon gas as protection gas during greying.
(5) mould material finally preparing is tested according to testing standard ASTM E1461-01, the thermal conductivity that test obtains is 1800W/mK.
Each embodiment of table 1 prepares the charing of graphene composite film, graphited condition and test result
To those skilled in the art, obviously the invention is not restricted to the details of above-mentioned one exemplary embodiment, and in the situation that not deviating from spirit of the present invention or essential characteristic, can realize the present invention with other specific form.Therefore, no matter from which point, all should regard embodiment as exemplary, and be nonrestrictive, scope of the present invention is limited by claims rather than above-mentioned explanation, is therefore intended to include in the present invention dropping on the implication that is equal to important document of claim and all changes in scope.
In addition, be to be understood that, although this specification sheets is described according to embodiment, but not each embodiment only comprises an independently technical scheme, this narrating mode of specification sheets is only for clarity sake, those skilled in the art should make specification sheets as a whole, and the technical scheme in each embodiment also can, through appropriately combined, form other embodiments that it will be appreciated by those skilled in the art that.