A kind of low-shrinkage micro-foamed polypropylene and preparation method thereof

Abstract

The invention discloses low-shrinkage micro-foaming polypropylene composed of the following raw material components by the weight percentage: 50-80% of polypropylene, 5-20% of a vinyl elastomer, 0-30% of a talc powder, 3-10% of a low-shrinkage masterbatch, 1-5% of a micro-foaming masterbatch, and 0.2-1% of a processing aid. Compared with conventional micro-foaming polypropylene, by adding the low-shrinkage masterbatch, the problem of too small molding size of a micro-foaming material is solved, gas marks, material spots, peeling layering and other appearance defects of the material can be effectively eliminated, and besides, the weight of products is facilitated to be greatly reduced. At the same time, the micro-foaming polypropylene has no need of changing a mold in the preparation process, has no need of increasing injection molding equipment, has no need of secondary mold opening, and has no need of increasing a mold cavity gas back pressure device, and thus the micro-foaming polypropylene products having the appearance and size consistent to those of common materials and having the weight reduced by 6-20% are prepared.

Description

technical field [0001] The invention belongs to the field of modified plastics, in particular to a low-shrinkage micro-foamed polypropylene and a preparation method thereof. Background technique [0002] Driven by the lightweight trend of automobiles, for the modified plastics industry, the micro-foamed polypropylene material has a dense surface layer and a foamed core layer structure, which has the most significant weight reduction effect and has almost no negative impact on the performance of the parts, so It has developed into the new favorite of various new material companies. However, micro-foamed polypropylene prepared by chemical foaming generally has problems such as air marks, material flowers and even peeling and delamination during the injection molding process. The usual solution is to pre-fill the cavity with counter-pressure gas, and at the same time In order to increase the weight reduction ratio, the secondary mold opening technology is used, but these measu...

AI Technical Summary

Problems solved by technology

However, the pressure formed by the foaming of the foaming agent will drop sharply with the increase of the foam pore size and the decrease of the temperature, which is far from the effect of the pressure maintaining of the injection molding machine, which eventually leads to the failure of the micro-foamed polypropylene parts. The size is 0.1~0.2% smaller than ordinary materials, and the micro-foamed polypropylene parts cannot be assembled without changing the mold

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