More than 40 years of history, the product has been on many electrical devices As a manufacturer of insulating material polyimide film, and achieved good results. But with the rapid development of small light microelectronic products, such as mobile phones, laptops, etc., that require high-density connector of the flexible printed wiring board more and more urgent. The technical requirements for flexible circuit boards with polyimide film is also rising. Because of commercial sensitivity, both of the polyimide precursor formulation, the manufacturing process conditions and the film or film making apparatus, although some have been described in several patent documents, but many details still not disclosed. With the improvement of technology requirements, polyimide CCL manufacturing technology has been steadily progressing.
Polyimide film used in flexible circuit board in addition to the requirements of high mechanical properties, dielectric properties, but also requires a low CTE and the inner surface of the isotropic. This is followed by two requirements must also be solved with a two-way stretch. Fully imidized polyimide due to the high glass transition temperature and rigidity of the molecular chain can not be drawn, the film may depend on the solvent content drawability. If the solids content to 60% of the gel film would be difficult to draw. Because it will break the MD drawing 1.05TD direction, so when drawing, a solids content of not more than 50%. Draft ratio control TD / MD for the in-plane isotropic is very important. Generally believed TD / MD = 0.9 ~ 1.3 as appropriate. Dehydrating agent is usually added acetic anhydride and a tertiary amine catalyst polyimide acid solution, partially imidized polyamic acid solution was then coated film. Gel film thus obtained can be peeled from the strip at high solvent content, the two-way stretch and heat treatment of high-performance thermal imidization of the polyimide film.