A kind of preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application

Abstract

The application discloses a preparation method of a hard elastic polypropylene film, a hard elastic polypropylene film and applications thereof. The preparation method of the present application includes raising the temperature according to one of the following two heating methods or a combination during the annealing treatment, and cooling according to one of the following two cooling methods or a combination; heating method 1, heating at a rate of 1‑5°C / min; heating method Second, keep warm after heating up to 70-100°C, and then keep warm for a period of time every 5-20°C; cooling method 1, cooling at a speed of 1-5°C / min; cooling method 2, keep warm for a period of time every 5-20°C, until Cool down to 70-100°C and keep it warm, then cool down from 70-100°C to room temperature. This application adopts slow or gradient heating and slow or gradient cooling, which can better maintain the initial crystallization of the cast film and maintain the consistent structure and stability after annealing, so that the prepared hard elastic polypropylene film has a good lamellar structure and orientation. A homogeneous pore structure polypropylene microporous membrane lays the foundation.

Description

A kind of preparation method of hard elastic polypropylene film, hard elastic polypropylene film and application technical field The application relates to the technical field of battery diaphragm production, particularly relate to a kind of preparation method of hard elastic polypropylene film Method, hard elastic polypropylene film and application. Background technique As the key material in the battery, the lithium battery separator not only plays the role of isolating the positive and negative electrodes, but also retains the channel for lithium ion transport. Polyolefin materials, such as polyethylene, polypropylene, etc., are classic polymer materials because of their excellent Its chemical resistance, processability and other properties are often used to prepare lithium battery separators. At present, polyolefin diaphragms are Process can be divided into wet film and dry film. The wet film is represented by polyethylene, the mechanism used is thermally indu...

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Problems solved by technology

[0005] However, it has been found in practical production that some lamellar crystals are still imperfect during annealing treatment, which is always accompanied by melting and recrystallization of imperfect crystals. Even if the temperature of annealing treatment is increased and the annealing time is prolonged, it is difficult to solve this problem; and, in During the annealing treatment, the initial crystallization of the cast film will be severely damaged, which is not conducive to controlling the structural consistency and stability after the annealing treatment and baking; these will affect the performance of the final stretched polyolefin microporous membrane

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