SMC (sheet molding compound) material for passenger car covering parts and preparation method thereof

Abstract

The invention discloses an SMC (sheet molding compound) material for passenger car covering parts and a preparation method thereof. The SMC material comprises 60-100 parts of base resin, 80-200 parts of reinforcing fiber, 30-50 parts of low shrinkage agent, 130-220 parts of inorganic mineral filler, 20-60 parts of hollow glass microsphere, 3-8 parts of releasing agent, 1-4 parts of curing agent and 1-5 parts of thickening agent. The hollow glass microspheres, of which the average particle size is less than 40 micrometers and the compression strength is greater than 37MPa, are utilized to lower the density of the material; the novel liquid releasing agent is used instead of the traditional releasing agent, so that the product surface can be directly painted without treatment; and PVAc / St copolymer and saturated polyester are utilized to compound the low shrinkage system, so that the material has zero shrinkage and satisfies the requirements for Grade A surfaces. The invention has the advantages of low specific gravity, no need of surface treatment and Grade A surface, and can be used for passenger car covering parts instead of steel materials.

Description

[0001] technical field [0002] The invention relates to the field of sheet molding compounds, in particular to an SMC material for passenger car panels with low specific gravity, no surface treatment and A-level surface characteristics and a preparation method thereof. Background technique [0003] Passenger car cover (referred to as cover), refers to the surface and interior of the special-shaped body that constitutes the body or cab, covers the engine and chassis, and the interior of the car. The cover is not only a decorative part, but also a closed shell-shaped force-bearing part. The shape of the automobile body is welded by many covering parts with large outline size and spatial surface shape, so there are high requirements for the dimensional accuracy and surface quality of the covering parts. Body panels require smooth surfaces, clear lines, and no surface defects such as wrinkles, scratches, and roughness. In addition, sufficient rigidity and dimensional stabi...

AI Technical Summary

Problems solved by technology

[0005] With the continuous improvement of people's environmental protection awareness and the successive introduction of environmental protection regulations in various countries, automobile weight reduction has become an inevitable trend in the future automobile development. SMC materials can be used to prepare low specific gravity composite materials. The general method used is to add hollow glass beads. However, the traditional mold release agent such as zinc stearate migrates to the surface of the product during the curing process to make the product easy to take out from the mold. The release agent on the surface has poor adhesion to the spray paint and must be polished or chemically used before painting. products for surface treatment

But in this way, the glass beads on the surface will break and appear many small pits, and the surface flatness will be poor after painting.