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 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 ordinary polypropylene (PP) raw material through three-layer co-extrusion o...

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 ordinary polypropylene (PP) raw material through three-layer co-extrusion of casting machine. The raw material determines that cast polypropylene film (CPP) has poor low temperature and freezing resistance, and cannot be used for packaging frozen products below 0 °C