Preparation method of low-temperature-resisting three-layer co-extruded composite thin film

Abstract

The invention discloses a preparation method of a low-temperature-resisting three-layer co-extruded composite thin film. The composite thin film is formed by co-extruding three layers through a casting machine and is provided with an outer layer, a middle layer and an inner layer, which are compounded together, wherein raw materials of the middle layer comprise metallocene linear low density polyethylene and polypropylene in a weight ratio of 1:10 to 1:1, and the fusion index of the metallocene linear low density polyethylene is 1-3.5. With the adoption of the scheme, when a conventional CPP (Chlorinated Polypropylene) thin film is compared with the low-temperature-resisting three-layer co-extruded composite thin film, the low-temperature-resisting and anti-freezing performance of the co-extruded three-layered composite thin film is greatly improved, the low-temperature-resisting three-layer co-extruded composite thin film can be normally used in an environment of -30 DEG C and the barrier property and the strength of the composite thin film are not influenced, and thus the low-temperature-resisting three-layer co-extruded composite thin film is particularly suitable for packaging of quick frozen products including dumplings, rice dumplings and the like.

Description

[0001] The patent application of the present invention is a divisional application titled "Low Temperature Resistant Three-Layer Co-extrusion Composite Film and Its Preparation Method", the filing date is 2010-07-08, and the application number is 201010225754.9. technical field [0002] The invention relates to a three-layer co-extruded composite film, in particular to a preparation method of a low-temperature resistant three-layer co-extruded composite film. Background technique [0003] At present, three-layer co-extruded composite films have been widely used in food, medicine, chemical and other fields, among which food packaging accounts for the largest proportion, such as beverage packaging, quick-frozen food packaging, cooking food packaging, fast food packaging, etc. These products All have brought great convenience to people's life. [0004] The existing three-layer co-extrusion composite film is mostly cast polypropylene film (CPP), which is made of common polypropy...

AI Technical Summary

Problems solved by technology

[0004] The existing three-layer co-extrusion composite film is mostly cast polypropylene film (CPP), which is made of common polypropylene (PP) raw material through three-layer co-extrusion of casting machine. This common PP film The raw material determines that the cast polypropylene film (CPP) has poor low temperature and freezing resistance, and cannot be used for packaging of frozen products below 0°C