In 1962, polyimide was studied in China, and polyimide varnish was successfully developed in 1963. In 1966, films, moulded plastics and adhesives were developed successively, and began to be commercialization in the middle of 80s. The industrialization of biaxial tensile process film began in 2005.
Cause of concern of polyimide film: 1. has excellent comprehensive performance 2. a variety of methods can be used in the synthesis 3.a variety of processing methods 4. application field is very extensive. Features: high and low temperature resistance, excellent mechanical properties, radiation resistance, solvent resistance, flame retardancy and excellent electrical properties. It is applied to aviation, aerospace electronics and electrical appliances, microelectronics, machinery and medical treatment. Major producers: 1. film: DuPont, Dongli DuPont, Zhongyuan Chemical, yupan Xingchan, South Korea. 2. coating: HD (DuPont and Hitachi into a joint venture), Ciba-Geigy, Asahi Asahi, Nippon Steel, Xinyue chemistry. 3. plastic: DuPont, moat Hing, Sabic (GE) (Ultem), Mitsui chemical (Aurum).
At present, there are two production processes in China: tape casting unidirectional tension and tape casting biaxial stretching process. The production of polyimide film is very large, most of which are township enterprises. The properties of polyimide film are low, the tolerance of thick and thin is large, and the coefficient of thermal expansion is large and asymmetric. It is not suitable for FCCL. The latter has fewer production enterprises, larger relative investment and higher technical requirements. The performance is higher than the former, especially the thermal expansion coefficient is low, the dimensional stability is good, and is suitable for FCCL. There is a great difference in character. The former has low income and the latter has high income.
China is a successful thermo amamination process, which has low investment, convenient solvent recovery and low cost. The main equipment can be domestically made, and the key equipment can be introduced. Chemical imidization technology is used abroad, with large investment, solvent recovery and high cost. Therefore, there is a large space for the price difference between the two.
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