Saloon car bumper special material capable of direct spray coating

Abstract

The invention discloses a special material for direct spray coating of a bumper, which is prepared by mixing of polypropylene, a rubber toughening agent, a crosslinking agent, grafted polypropylene, inorganic filler, black master bath, an antioxidant and a light stabilizer in proportion, preparation of the master bath, dynamic vulcanization, secondary extrusion, multi-monomer fusing and grafting, etc. The polarity of the special material for the bumper is changed by multi-monomer fusing and grafting modification of methyl methacrylate and so on, and the surface activity of the special material for the bumper is increased; and spray coating paint of the bumper comprises a plurality of chemical compositions, the appetency of various compositions and given functional groups is insufficient, a plurality of active functional groups are formed on the surface of the material by activation of a plurality of functional groups and can simultaneously form physical absorption or chemical bonding with the various chemical compositions in the paint, thereby the special material can perform direct spray coating without flame treating, achieves the optimum spray coating effect, and has good processing fluidity and high toughness.

Description

technical field [0001] The invention relates to an improved polypropylene new material, in particular to a special material for car bumpers with high toughness and high fluidity which can be directly sprayed. Background technique [0002] Polypropylene plastic (PP) lacks polar groups in its molecules. It is a non-polar material and has poor affinity with polar materials such as paint. The bumper must go through a flame treatment process before spraying. Sometimes, if the flame is not handled properly, the whole batch of painted bumpers will be scrapped, causing heavy losses. Chinese patent CN101070417A discusses grafting polypropylene with maleic anhydride (MAH), but the boiling point of maleic anhydride is low, the grafting process is easy to sublime, and it is corrosive to equipment. Chinese patent CN1235989A discloses the use of glycidyl methacrylate (GMA) as a graft monomer, which reduces the melt flow rate of the material significantly, and increases the fluidity of th...

AI Technical Summary

Problems solved by technology

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

Chinese patent CN101070417A discusses grafting polypropylene with maleic anhydride (MAH), but the boiling point of maleic anhydride is low, the grafting process is easy to sublime, and it is corrosive to equipment

Chinese patent CN1235989A discloses the use of glycidyl methacrylate (GMA) as a grafting monomer, which reduces the melt flow rate of the material significantly, and improves the fluidity by increasing monomers such as small molecular weight polypropylene. Other properties of materials

Chinese patent CN1211590, etc. have described the use of thermoplastic elastomer POE as a toughening agent, but this toughening agent can only be physically blended with the matrix polypropylene plastic (PP) to achieve the purpose of toughening, and its blend shape and structure are not enough. Stablize

[0004] At present, the thermal expansion coefficient of the bumper material is high, and the fixing process and size matching of the bumper are required to be high. As a result, the size of the bumper changes due to temperature changes during use, resulting in deformation of the bumper and internal stress, which is easy to cause damage to the bumper. Loosening or breaking of bars