30results about How to "Improve biaxial tensile properties" patented technology

The invention discloses a heat conduction graphite sheet and a manufacturing method thereof. The heat conduction graphite sheet consists of a polyimide film, a first coating layer and a second coating layer, wherein the first coating layer and the second coating layer are positioned on the upper and lower surfaces of the polyimide film respectively and are formed by sintering graphite modifiers respectively; each graphite modifier consists of the following components in parts by weight: 20-25 parts of benzophenonetetracarboxylic dianhydride, 14-16 parts of benzenetetracarboxylic anhydride, 22-26 parts of diaminodiphenylmethane, 20-25 parts of dimethyl formamide, 8-10 parts of N-methyl pyrrolidinone, 1.8-2.5 parts of ethylene glycol and 2.5-3 parts of polydimethylsiloxane. The heat conduction performance of the heat conduction graphite sheet is improved in the vertical direction and the horizontal direction, local overheating is avoided, the uniformity of the heat conduction performance is realized, and meanwhile, the stability and reliability of the heat dissipation performance of a product are improved; the cost of the product is greatly reduced.

The invention relates to a preparation process for a graphite heat conduction and dissipation patch. A first coating layer of the graphite heat conduction and dissipation patch is formed from a graphite modifier applied onto the upper surface of a polyimide thin film, and the graphite modifier comprises the following constituents by weight percent: benzophenonetetracarboxylic dianhydride, pyromellitic dinahydride anhydride, diaminodiphenylmethane, dimethylformamide, N-methyl-2-pyrrolidone, ethylene glycol, polydimethylsiloxane and dibutyl phthalate. The preparation process comprises the following steps of applying the graphite modifier onto the upper surface of the polyimide thin film to obtain the processed polyimide thin film; rising the temperature of a carbonization film to be 2,350-2,450 DEG C, carrying out heat preservation, rising the temperature again to be 2,850-2,950 DEG C, and cooling the carbonization film to obtain a graphite film mainly sintered. By the preparation process, local heating is prevented, the uniformity of heat conduction performance is achieved, meanwhile, the stability and the reliability of heat dissipation performance of a product are improved, and the product cost is greatly reduced.

A manufacturing process for graphite radiating fins of the invention comprises the following steps: coating the upper and lower surfaces of a polyimide film with a layer of graphite modifier, wherein the polyimide film after processing is composed of a polyimide film, a first coating layer and a second coating layer, and the graphite modifier comprises, by weight, 20-25 parts of benzophenonetetracarboxylic dianhydride, 12-18 parts of pyromellitic dianhydride, 20-28 parts of diaminodiphenyl methane, 20-25 parts of dimethylformamide, 8-10 parts of N-methyl pyrrolidone, 1.5-2.5 parts of ethylene glycol, 2-3 parts of polydimethylsiloxane, and 0.8-1.5 parts of dibutyl phthalate; heating the polyimide film after processing from room temperature to 1200 DEG C to obtain a pre-fired carbonized film; and heating the carbonized film to 2850-2950 DEG C to obtain a fired graphite film. Uniform heat conduction performance is achieved, and meanwhile, the radiating performance, stability and reliability of products are improved, and the cost of products is greatly reduced.

The invention discloses a heat conduction graphite patch for a microelectronic device. The heat conduction graphite patch comprises a first heat conduction adhesive layer, a graphite layer and a second heat conduction adhesive layer, the graphite layer is obtained through the following technique, and the technique comprises the following steps that the upper surface and the lower surface of a polyimide film after the first step are coated with graphite modifiers to obtain the processed polyimide film; the processed polyimide film is heated to 800 DEG C, heat preservation is carried out, and then the film is heated to 1200 DEG C to obtain a pre-burned carbonization film; a calender is adopted to calender the pre-burned carbonization film in the fourth step; the carbonization film is heated to 2400 DEG C, heat preservation is carried out, then the film is heated to 2900 DEG C, and therefore a mainly-burnt graphite film is obtained; the mainly-burnt graphite film obtained in the fifth step is calendered to obtain the graphite layer. The method avoids local overheating of adhesive tape, uniformity of heat conduction performance of the adhesive tape is achieved, the stability and reliability of heat dissipation performance of the patch are improved, and the cost of the patch is greatly reduced.