Low-after-shrinkage polypropylene composite material for vehicles and preparation method thereof

Abstract

The invention provides a low-after-shrinkage polypropylene composite material for vehicles and a preparation method thereof. A polypropylene composition is prepared from raw materials in parts by weight: 50 to 65 parts of polypropylene, 5 to 15 parts of an impact modifier polyolefin elastomer, 15 to 25 parts of talcum powder, 5 to 10 parts of ultrahigh molecular weight polyethylene, 5 to 10 partsof a nano glass body and 0.1 to 0.5 part of an antioxidant; the nano glass body is a nano glass body subjected to organic matter surface treatment and spatial three-dimensional flat structural treatment, and the organic matter is a styrene-glycidyl methacrylate random copolymer. According to the invention, the ultrahigh molecular weight polyethylene and the nano glass body are added into the polypropylene at the same time, so that the post-shrinkage rate can be synergistically improved, and the compatibility of the ultrahigh molecular weight polyethylene and a PP matrix can be improved, and thus the impact property of the material is maintained.

Description

technical field [0001] The invention relates to the technical field of modified materials, in particular to a polypropylene composite material for vehicles with low after-shrinkage rate and a preparation method thereof. Background technique [0002] Polypropylene (PP) material has been widely used in various assembly systems of automobiles due to its good comprehensive performance. Most of the exterior and interior parts of automobiles are obtained by injection molding of polypropylene composite materials. The exterior parts such as bumpers, door sills, skirts, etc., and the interior parts of automobiles such as instrument panels, pillars, glove boxes, door panels, etc. Some automotive exterior parts need to be sprayed, and some interior parts need to go through post-treatment processes such as skin coating. After 24h-48h of injection molding, the material parts will shrink once due to the rearrangement of molecular chain crystallization. In post-treatment processes such as...

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Problems solved by technology

[0003]At present, most automobile OEMs use polypropylene modified material as PP+EPDM-TD10-TD30. After post-treatment, it will usually shrink by 0.15-0.2 % or so, it cannot meet the strict size requirements of the parts, such as bumpers, etc.

[0004]Patent No. CN107540954A is compounded by adding glass fiber powder and superfine calcium carbonate. The addition of glass fiber powder will affect the appearance of the product, and floating fibers are prone to appear; while calcium carbonate The addition of will affect the rigidity of the material, and it is difficult to meet the requirements of products with high rigidity-toughness balance requirements;

[0005] Patent No. CN106280010A compounded by adding acrylonitrile-butadiene-styrene copolymer and basic magnesium sulfate whisker, acrylonitrile-butadiene-styrene The compatibility between the copolymer and PP is poor, and it needs to be improved by adding a specific compatibilizer, while the acrylonitrile-butadiene-styrene and the compatibilizer have a strong odor, so it is difficult to apply to interior products with high odor , and the price of this raw material is much higher than that of PP materials, which will lead to a sharp increase in costs

[0006]Patent No. CN108148286A is compounded by adding high-density polyethylene, glass fiber powder, and high-mesh glass fiber powder. Adding glass fiber powder will affect the appearance of the product, and because Glass fiber powder has a certain length-to-diameter ratio, and the product is prone to warping. Adding high-density polyethylene, because of its small molecular weight, will improve the impact performance of the material, but it will make little contribution to the improvement of the post-shrinkage of the product.

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