Polypropylene composite material for automobile bumper and prepn. thereof

Abstract

This invention discloses a kind of polypropylene composite materials for automobile bumpers and its preparation method. This kind of materials comprises 93.3~56.5wt% polypropylene, 0.2~1.5wt% thermo-stabilizers, 0.3~1wt% photo-stabilizers, 0.2~1% auxiliary reagents, 1~20wt% activating and reinforcing masterbatches and 5~20wt% stuffing masterbatches. The product in this invention has high surface activity, low thermo expansion rate and high thermo expansion temperature. The surface tension is 40mN / m, the linear thermo expansion rate is 10 to the power -6 to 10 to the power -7 mm per mm per deg. C, the thermo deformation temperature is 55 deg. C and some other technological indices all reach or exceed current standards for automobile materials. Thanks to the high surface tension and strong paint-adhesion of the bumpers made of this kind of materials, paints can be directly sprayed rather than flame processing. The thermo expansion rate is low, and therefore, loosening due to significant deformation might not occur with large temperature variation. Besides, it also has the advantages of high the thermo resistant temperature, short baking time and high production efficiency.

Description

technical field [0001] The invention relates to a propylene composite material and a preparation method thereof, in particular to a high-activity low-expansion heat-resistant polypropylene composite material for automobile bumpers and a preparation method thereof. Background technique [0002] In the field of automotive materials, materials for cars represent the current highest level. At present, the bumper material of cars is generally EPDM modified polypropylene, and the amount of this material reaches more than 70% of the total amount of bumper materials. [0003] At present, whether it is foreign or domestic bumper materials, although they have reached the current automotive material standards, there are still deficiencies in certain processing aspects, which need to be compensated by increasing the processing technology of auto parts manufacturers, which increases production costs. Can not fully meet the bumper material market demand. A few representative questions a...

AI Technical Summary

Problems solved by technology

Sometimes if the flame is not handled properly, the whole batch of painted bumpers will be scrapped, causing heavy losses

[0005] The current bumper material has a high coefficient of thermal expansion, which requires high fixing process and dimensional matching of the bumper, and causes the size of the bumper to change due to temperature changes during use, resulting in deformation of the bumper and internal stress, which is easy to cause Loose or broken bumper

[0006] The bumper must go through two baking processes during the painting process. The heat resistance of the current bumper material is not high enough. In order to ensure that the bumper does not deform during the baking process and the paint is completely cured, the baking temperature is generally set at At around 80°C, it takes 3 to 3.5 hours to paint such a bumper from the on-line to the off-line, and the production efficiency is low