Technique and equipment for fabricating plastic sheet material produced from molding laminar die in low pressure

Abstract

The invention relates to a low-pressure molding sheet molding compound sheet and its production process and equipment. The sheet adopts the following raw materials in parts by mass, matrix resin: 50-80 parts of unsaturated polyester resin; thickener: 5-20 parts of crystalline resin; 20-50 parts of low-shrinkage additive; 0.8-1.2 parts of initiator 0.5-1 part of polymerization inhibitor; 2-4 parts of internal mold release agent; 80-200 parts of filler, and chopped glass fiber accounts for 20-35% of the total mass of the sheet. And it is made by the production process of resin paste preparation, thickening, processing into sheets by equipment and sealing packaging. The sheet provided by the invention can reach the molded state after being placed at room temperature for 2-3 hours, and can be well formed under the conditions of 1-3MPa unit pressure and 80-120°C mold temperature, and at the same time obtains conventional molding that can be formed with high temperature and high pressure Compared with the performance of products, it greatly reduces the requirements for forming presses and molds.

Description

technical field [0001] The invention relates to a production equipment and application of low-pressure molding sheet molding compound sheet. Background technique [0002] At present, with the continuous expansion of industrialization and automated production scale, the production of low-pressure molding sheet molding compound (hereinafter referred to as low-pressure SMC) sheets in the polyester molding compound market is becoming more and more popular, and its status is becoming more and more important. However, due to the high molding pressure of 3.5-7.0 MPa in the production process of traditional SMC, it is necessary to invest a lot of money to purchase expensive production molding equipment; energy, resulting in relatively high production costs. [0003] If crystalline resin is used as a low-pressure SMC thickener, the molding pressure is 1.0-3.0MPa, and the molding temperature is 80-120°C. In this way, the above disadvantages can be overcome in terms of equipment and e...

AI Technical Summary

Problems solved by technology

The crystalline resin recrystallized into a solid state is unevenly distributed in the resin paste, forming hard lumps, which will seriously affect the impregnation effect of the resin paste on the fibers when producing sheets.

In addition, the uneven hard group crystalline resin is easy to adhere to the scraper of the sheet machine, blocking the gap between the scraper and the PE film, and affecting the continuous production of the sheet

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