Low after-shrinkage polypropylene composite for car bumper bar and preparation method of low after-shrinkage polypropylene composite

Abstract

The invention provides a low after-shrinkage polypropylene composite for a car bumper bar and a preparation method of the low after-shrinkage polypropylene composite. The low after-shrinkage polypropylene composite is prepared from 100 parts of polypropylene, 15-30 parts of acrylonitrile-butadiene-styrene, 15-45 parts of basic magnesium sulfate crystal whiskers, 10-35 parts of high-mesh talcum powder, 25-45 parts of flexibilizer, 0.25-0.5 part of nucleating agent, 0.4-0.8 part of lubricating agent, 0.2-0.3 part of coupling agent and 0.15-0.4 part of antioxygen. An acrylonitrile-butadiene-styrene copolymer, the basic magnesium sulfate crystal whiskers, the nucleating agent, the flexibilizer and the like are added into polypropylene to influence the crystallization property of PP, therefore, the shrinkage rate of the PP composite is reduced, the shrinkage rate change before and after coating of the prepared polypropylene composite is smaller than 0.1%, and the requirement of the car bumper bar is met.

Description

technical field [0001] The invention relates to the field of polymer material modification, in particular to a low aftershrinkage polypropylene composite material for automobile bumpers and a preparation method thereof. Background technique [0002] Polypropylene (PP) is widely used due to its low price, easy processing and molding, low density, chemical corrosion resistance and excellent physical and mechanical properties, and it has become one of the fastest growing general-purpose plastics. In recent years, with the requirements of automobile lightweight and the development of plastic modification industry, plastic materials are increasingly used in automobiles, electronic appliances, home appliances and other industries to meet the requirements of lightweight, energy saving and emission reduction. Polypropylene (PP) is widely used in automotive interior and exterior trims, such as bumpers, door panels, instrument panels, pillars, and steering wheels, due to its advantage...

AI Technical Summary

Problems solved by technology

[0004] However, the above three methods all have disadvantages, which are: adding fillers or increasing the amount of fillers, which will inevitably lead to a decrease in material toughness; adding glass fibers will inevitably bring about injection molding problems such as floating fibers and warping; adding toughening agents The content will inevitably bring about the increase of cost and the decrease of modulus

[0005] At present, most automobile OEMs use polypropylene modified materials as PP+EPDM-TD15~TD30 materials. The shrinkage rate of such materials after injection molding for 24h~48h is 0.8~1.3%, and the shrinkage rate after spraying for 24h~48h It is 1.0~1.5% (the spraying condition is 85°C, 40min), and the shrinkage rate before and after spraying changes by 0.2%, which cannot meet the requirements of automobile bumpers