Method for increasing rolling length of thin films

Abstract

The invention discloses a method for increasing the winding length of a film. The method is to feed in a material as a separation layer during the film winding process so that the material is wound between the film layers. In the present invention, by setting a separation layer between the film layers, on the one hand, the stress release of the films inside and outside the separation layer can be offset to obtain a film roll with a smooth surface; The outer diameter of the winding tube core is reduced, so that the limit length of the film that can be rolled is increased. Therefore, through the number of layers of the separation layer, any required film length can be rolled, which can meet various needs of industrial applications.

Description

technical field [0001] The invention relates to a method for increasing the winding length of a film, and belongs to the technical field of film winding. Background technique [0002] The production of film is generally tape casting or blow molding, and the formed film needs a special winding device to wind it up. Because the quality of film winding is mainly affected by the tension of film winding, if the tension is too high, the winding is too tight, and the film is prone to wrinkles; It is easy to produce axial slippage and serious misalignment on the die, so that it cannot be unloaded. As the diameter of the parent roll increases, if the speed of the winding roller remains unchanged, the tension of the winding will inevitably increase as the winding line speed increases (because the speed of the film sent from the traction device is constant) , this will not only cause the inner looseness and outer tightness of the roll film, the outer film will wrinkle the inner film,...

AI Technical Summary

Problems solved by technology

Because the quality of film winding is mainly affected by the tension of film winding, if the tension is too high, the winding is too tight, and the film is prone to wrinkles; It is easy to produce axial slippage and serious misalignment on the die, so that it cannot be unloaded

As the diameter of the parent roll increases, if the speed of the winding roller remains unchanged, the tension of the winding will inevitably increase as the winding line speed increases (because the speed of the film sent from the traction device is constant) , this will not only cause the inner looseness and outer tightness of the roll film, the outer film will wrinkle the inner film, but also increase the difficulty of rewinding during slitting and affect the quality of slitting. Therefore, in order to avoid the above effects, each specification of tube The length of the film carried by the core has a limit value, especially in the field of lithium battery separators, generally a roll is about 1000 meters

However, with the widespread industrial application of lithium battery separators, the market urgently needs to increase the winding length of the film to facilitate industrial operations. In order to achieve this goal, an elastic surface layer is currently added to the surface of the winding roller to buffer the internal stress. However, this method of adding a buffer layer on the surface of the die can only increase the film winding length from 1,000 meters to about 1,500 meters under the same conditions. The improvement is limited and still cannot meet the requirements of industrial applications. , so the market urgently needs a technology that can significantly increase the length of film winding

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