PP (polypropylene) composite for thin-walled automobile bumper and preparation method of PP composite

Abstract

The invention discloses a PP (polypropylene) composite for a thin-walled automobile bumper and a preparation method of the PP composite. The PP composite is mainly prepared from 10-30 parts of novel talcum powder subjected to surface modification with an ultrafine silane dispersant and having high regularity and large diameter-thickness ratio, 50-80 parts of conventional PP, 8-20 parts of an elastomer, 0.1-1 part of an antioxidant and 0-3 parts of other auxiliaries. The modified special talcum powder which is subjected to surface modification with the ultrafine silane functional dispersant and has the large diameter-thickness ratio and high lamella integrity is adopted as a filling modification component of the PP composite and is subjected to extrusion pelletization with PP, the elastomer, the antioxidant, an illumination auxiliary and the like by a double-screw extruder, and the PP composite is prepared accordingly. According to the prepared composite, liquidity of the composite is greatly improved while impact toughness and rigidity of the composite are improved, linear thermal expansion coefficient and shrinking percentage of the composite are reduced and dimensional stability and corresponding mechanical properties of a thin-walled bumper sample piece are guaranteed.

Description

technical field [0001] The invention relates to a functional polypropylene material and a preparation method thereof, in particular to a polypropylene composite material for a thin-walled automobile bumper and a preparation method thereof, belonging to the technical field of polypropylene. Background technique [0002] Due to its low density, high cost performance, excellent heat resistance and easy molding process, polypropylene has become one of the most used and fastest growing plastic varieties in automotive plastics. In recent years, with the maturity of polypropylene composite material modification technology and the development of plastic molding processing technology, the use of polypropylene modified materials to manufacture automobile bumpers has accounted for more than 80%, and will further increase in the future. [0003] However, with the rapid development of the automobile industry in recent years, light weight, high quality, energy saving, environmental protec...

AI Technical Summary

Problems solved by technology

Taking polypropylene composite car bumper as an example, its single-piece product has a large size (up to 1m in length) and a high gram weight (up to 3Kg or more), which is a hot spot in current automotive lightweight research. Among them, the most effective way to achieve lightweight The method is to design thin-walled samples, but the reduction of sample wall thickness will undoubtedly have a series of adverse effects on its mechanical properties, high and low temperature dimensional stability and other application properties. In order to improve the above defects, polypropylene materials at home and abroad Modification experts have proposed a series of improvement methods. At present, there are two main methods: 1. Adding fibrous fillers such as glass fibers and mineral whiskers with a certain length-to-diameter ratio through side feeding to further reduce the composite The linear expansion coefficient and shrinkage rate of the material increase the rigidity of the material to meet the new requirements of thin-walled bumper composite materials. However, on the one hand, this method results in the cost of composite materials due to the high cost of raw materials for fibrous fillers such as whiskers. increase, on the other hand, because the addition of fibrous fillers such as whiskers destroys the impact toughness of the composite material, and because the fibrous fillers such as glass fibers are easily exposed, the appearance quality of the sample will decrease significantly. For example, the patent CN105778297A discloses a A polypropylene composite material with high modulus and low shrinkage, which is prepared by adding 15-35% fibrous inorganic powder and talc powder to form a composite inorganic reinforcement system, and is applied to automobile thin-walled bumpers

2. By adding a new type of toughening agent to change the toughening system of the composite material to reduce the shrinkage rate of the material and increase the toughness of the composite material, but the rigidity of the composite material prepared by this method is often not high and cannot meet the application of thin-walled bumpers The demand is only applicable to automobile bumper products with conventional thickness. At the same time, the added rubber components are expensive, which increases the cost of composite materials and is not conducive to market competition. For example, patent CN104893106A discloses a polypropylene composite material for high impact-resistant automobile bumpers And the method thereof, by adopting thermoplastic polyurethane elastomer and nitrile rubber to replace currently commonly used toughening agents such as ethylene-propylene rubber, POE, SBS, etc., to achieve the purpose of reducing the shrinkage rate of the material and increasing the toughness of the material

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