Biodegradable multilayer composite polyethylene film and preparation method thereof

Abstract

The invention relates to a biodegradable multilayer composite polyethylene film and a preparation method thereof. The film comprises the following three layers: (1) a polyethylene internal layer containing an inorganic filling material; (2) a polyethylene middle layer containing a compatibilizer; (3) a polyethylene external layer containing starch, grease and metallocene polyethylene. The preparation method provided in the invention comprises the following steps: (1) respectively mixing master batch components in each layer of the composite film and subjecting an obtained mixture to melt plasticization at a temperature of 70 to 200 DEG C; (2) allowing raw materials in each layer after melt plasticization to enter into a same die and carrying out co-extrusion to obtain the multilayer composite film. The biodegradable multilayer composite polyethylene film provided in the invention can maintain its inherent physical and mechanical properties for a long time under normal storage and usage conditions; once the film turns into waste, under the action of the factors of water, microbes and the like, the strength of the film decreases in a short time, the film undergoes fragmentation and returns back to nature, thereby posing no harm to environment, and a fast degradation speed and a good degradation effect are achieved.

Description

Technical field [0001] The invention belongs to a plastic packaging material, and specifically relates to a biodegradable multilayer composite polyethylene film and a preparation method thereof. Background technique [0002] With the rapid development of my country's commodity economy, the demand for plastic packaging materials is increasing year by year. Among them, polyethylene (PE) is the most important plastic raw material, and its products are widely used in fields such as agricultural film and packaging materials. However, its pollution to the environment has also become prominent. This is because polyethylene is difficult to be degraded by sunlight and microorganisms. The long-term existence of its waste outdoors will cause "white pollution", turning "white pollution" into harmless, which has become a top priority. The ease of biodegradation of polyethylene is related to its molecular weight, and branched and above 20 carbon alkanes are difficult to biodegrade. Therefor...

AI Technical Summary

Problems solved by technology

For example, direct mechanical blending will lead to a lack of adhesion between the two phases of the separation system; when co-extruding a multilayer polyethylene film, often due to the mismatch of melt viscosity between layers, the fluidity and The melt viscosity does not match, so that one layer in a certain section of the local section of the film is easily squeezed out by another layer, resulting in a crystal point

[0004] U.S. Patent US 4133784 uses ethylene-acrylic acid copolymer and starch to modify polyethylene after blending, but due to too many modified substances, the physical properties of the film are reduced

Chinese patent CN 200810011021 uses bio-based material polylactic acid and polyethylene blending for modification, but the cost is high and the process is complicated