A kind of low thermal expansion coefficient polyimide film and preparation method thereof

Abstract

The invention discloses a polyimide film with a low thermal expansion coefficient and a preparation method thereof, which belongs to the technical field of film preparation of high molecular polymer materials. ‑After completely dissolving in dimethylacetamide, add metered pyromellitic dianhydride at one time, add a small amount of amine catalyst when it is completely dissolved, and then add metered p-phenylene diisocyanate in batches until there is no CO2 gas Released to obtain a homogeneous and transparent polyamic acid solution with a p-phenylene imine group introduced, vacuum defoaming, extrusion salivation, biaxial stretching and heating imidization to obtain a polyamide with a thermal expansion coefficient that can reach a minimum of 15ppm / ℃ The imine film has the advantages of strong versatility and high degree of industrialization, avoids the defect of high difficulty in chemical imidization technology, and can meet strict environmental protection requirements.

Description

technical field [0001] The invention relates to the technical field of polymer film preparation, in particular to a preparation method of a low thermal expansion coefficient polyimide film. Background technique [0002] With the rapid development of modern electronic products, the requirements for high-density connected flexible printed circuit boards (FPC) are getting higher and higher. Usually, FPC is coated with adhesive on the substrate polyimide film and then laminated with copper foil. It is made of polyimide film copper clad laminate (FCCL), and then formed into a copper winding circuit product. Therefore, FCCL as the raw material of FPC must have better dimensional stability, and starting from the current FCCL preparation process, the polyimide film characteristics of its substrate have become the main factor that has a great impact on the change of FCCL. Therefore, the polyimide film has a high modulus, and it is even more critical that the coefficient of thermal e...

AI Technical Summary

Problems solved by technology

[0003] At present, although there are three types of commercial polyimide films used on FPC by DuPont Company of the United States, Ube Industries of Japan and Zhongyuan Company of Japan, according to relevant reports, the typical preparation method of the film is through chemical imidization. To achieve, the technical difficulty is extremely high, resulting in expensive products

At present, the research and development of chemical imidization of polyimide film has been carried out in China, but it is still in its infancy, and there is no batch product coming out. With the increasingly stringent environmental protection requirements, its technical difficulty is higher

However, the domestic polyimide film is limited by the conventional thermal imidization preparation technology, and its CTE is still difficult to approach 18ppm / ℃ of copper foil, which cannot meet the requirements for the manufacture and use of high-functional FPC, and the reaction by-products are highly polluting. , cannot meet the increasingly stringent environmental protection requirements

[0004] Professor Kuangjun Hasegawa, Department of Chemistry, Faculty of Science, Toho University, Japan, in "Membrane Forming Method and Physical Properties of Polyimide", introduced the reaction of s-BPDA and PDA first, and then added the remaining diaminobenzidine diimide to polymerize The polyamic acid with imine group is formed, and the polyimide film with low CTE is obtained after thermal imidization, but the preparation of diaminodiimine monomer is cumbersome, and it is generally made by the laboratory, which is difficult to produce on a large scale , so there is no commercially available product for diaminodiimide monomers, and now there is a need for a polyimide film manufacturing method with strong versatility, high industrialization degree and low technical difficulty

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