Method for separating polyvinyl dichloride (PVDC) thin film and method for preparing PVDC composite film

Abstract

The invention discloses a method for separating a polyvinyl dichloride (PVDC) thin film and a method for preparing a PVDC composite film. The separation method comprises the following steps of: respectively adhering thickened layers on two sides of a double-layer PVDC thin film serving as a middle layer, and separating the double-layer PVDC thin film from the middle to obtain the PVDC thin film. The preparation method comprises the following steps of: respectively compositing first films to be composited on two sides of the double-layer PVDC thin film serving as the middle layer through an adhesive, and separating the double-layer PVDC thin film from the middle to obtain the PVDC composite film. By the method for separating the PVDC thin film, the efficiency of separating the double-layer PVDC thin film is improved, the problem of high rejection rate caused by drapes of a single-layer PVDC thin film easily produced during separation of the single-layer PVDC thin film is effectively solved, and the separation quality is improved. By the method for preparing the PVDC composite film, the production efficiency, the production quality and the yield of the PVDC composite film are improved.

Description

technical field [0001] The invention belongs to the technical field of composite membranes, and in particular relates to a separation method of PVDC thin films and a preparation method of PVDC composite membranes. Background technique [0002] PVDC (polyvinylidene chloride) film has become the best material choice for food packaging due to its excellent oxygen barrier, moisture barrier and high temperature cooking resistance. The conventional PVDC film is a naturally laminated double-layer film produced by the inflation method, with a thickness of 40±2μm, and is mainly used as a sheet casing film. The PVDC film used as a substrate film is a single layer, and the thickness is usually controlled to be 10-20 μm. Therefore, when preparing a PVDC composite film, it is necessary to separate the double-layer PVDC film. The traditional PVDC composite film preparation method is: first separate and then compound, that is, after the double-layer PVDC film roll is produced from the fil...

AI Technical Summary

Problems solved by technology

However, due to the relatively large deviation of single-layer thickness of PVDC blown film, when the double-layer PVDC film is separated, longitudinal or oblique stripes are likely to occur in the thinner part; in addition, due to the electrostatic adsorption between the two layers of film, the two-layer film The adsorption strength between the two layers is relatively high, resulting in a low separation speed of the double-layer film, usually 10-80m / min, which seriously affects the production efficiency of the PVDC substrate film; and the single-layer film is easily deformed and wrinkled during winding, and the subsequent compounding In the process, it is easy to affect the quality of the composite film because the single-layer film cannot be flattened. In serious cases, the entire roll of substrate will be scrapped, causing heavy losses to the production of the composite film.