In actual production, due to problems such as uneven density distribution of the raw resin, uneven mixing and kneading, and uneven tension during stretching, polytetrafluoroethylene microporous membranes often have uneven thickness.
In order to solve this problem, a multi-pass stretching process is adopted.
In the multi-pass stretching process, the multi-roller combination mechanism plays a very important role.
In a multi-roller mechanism, the surface of each roller is specially processed and different; at the same time, the working linear speed of each roller is also different.
In different time periods and under different temperature conditions, the PTFE fiber or membrane is stretched to varying degrees, and the entire stretching process is reasonably allocated to several different processes. In a single process, the fiber or membrane is stretched The stretching ratio is controlled at a low level, and sufficient heat treatment and retraction time is allowed, while ensuring the stretching effect of the PTFE fiber or film.
It well solves the problem of uneven thickness distribution of polytetrafluoroethylene microporous membranes.
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