Do you know the production method of polyimide films?
The production of polyimide films is basically a two-step process.
Step 1: synthesis of polyimide acid, Step 2: film-forming imidization.
Film forming methods mainly include impregnation method (or aluminum foil gluing method), cast method and saliva stretching method.
Dipping method equipment is simple, simple process, but the film surface is often sticky aluminum powder, film length is limited, low production efficiency, this method is not suitable for development.
The equipment precision of the salivation method is high, the film uniformity is good, the surface is clean and flat, the film length is not restricted, the film can be produced continuously, the film performance is good in all aspects, and the film with general requirements can be produced by this method.
The film produced by stretching method has significantly improved performance, but the process is complicated with harsh production conditions, large investment and high product price, and only high quality film is used in this method.
Main equipment of salivation method: stainless steel resin solution storage tank, salivation nozzle, salivation machine, imidizing furnace, winder and hot air system, etc. Preparation steps: The polyamide acid solution after defoaming is pressed from the stainless steel solution storage tank into the salivation nozzle storage tank on the front machine head through the pipeline. The steel belt runs at a uniform speed in the direction shown in the figure, and the solution in the storage tank is taken away by the scraper in front of the salivation nozzle, and a liquid film of uniform thickness is formed, and then it enters the drying channel for drying. The clean and dry air is sent to the heater by the blower to preheat to a certain temperature and then enters the upper and lower drying channels. The direction of hot air flow is opposite to the running direction of the steel belt, so that the temperature of the liquid film rises gradually during drying and the solvent evaporates gradually to increase the drying effect. When the polyamide acid film runs on the steel belt for one week, the solvent evaporates and becomes solid film, and the film peeled off from the steel belt is led to the imidizing furnace by the guide roller. The imidizing furnace is generally in the form of multiple rollers, and the guide rollers, which are synchronized with the speed of the salivating machine, guide the polyamide acid film into the imidizing furnace, and after high temperature imidizing, the film is wound up by the winder.
