Unsaturated polyester resin for moulding compound and preparation thereof

Abstract

The invention relates to unsaturated polyester resins and provides an unsaturated polyester resin used for molding compounds. The resin is prepared by dissolving the polymer of propanediol, glycol, dipropylene glycol, phthalandione and maleic anhydride in styrene. The invention has the advantages that: (1) the dipropylene glycol and methyl propanediol are adopted for synthesizing the unsaturated polyester resin to lead the resin to have favorable water resistance and flexibility, besides, the product of the resin has good moisture resistant capacity and excellent mechanical property; (2) when the resin is matched with proper low profile agent for use, the product can reach zero shrinkage, with the precision of size ensured; and (3) the phthalandione can be used for shortening reaction time and reducing energy consumption.

Description

1. Technical field [0001] The invention belongs to the field of macromolecule chemical industry, and in particular relates to unsaturated polyester resin. 2. Technical Background [0002] After decades of development, FRP products have changed from traditional manual production to highly mechanized molding production, and the production efficiency and product quality stability have been greatly improved. Of course, there are also requirements for unsaturated polyester resin. Very demanding. Most of the resins originally used for hand lay-up cannot meet the requirements of molding, such as insufficient reactivity of the resin, excessive shrinkage of the resin after curing, poor compatibility between the resin and the low-shrinkage agent, and so on. So so far, some resin production enterprises or research units have also developed unsaturated resins for different purposes according to the requirements of the molding process. From the raw materials (mainly from the dibasic ac...

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Problems solved by technology

From the raw materials (mainly from the dibasic acid or dibasic anhydride used), these resins can be divided into isophthalic and orthophthalic types. The dibasic acid used in isophthalic resins is isophthalic acid, and the reaction time is longer. The price of phthalic acid is high, and the current domestic application is not too wide; the ortho-phthalic resin uses phthalic anhydride, the reaction time is moderate, and the price of phthalic anhydride is much lower than that of isophthalic acid , so in China mainly use ortho-phthalic resins, but the difference in quality between ortho-phthalic and iso-phthalic resins is relatively obvious, especially the use of products in demanding electrical appliances is limited

On the other hand, the currently used low-shrinkage agents are mainly prepared by swelling polystyrene into styrene, which has the advantage of good coloring properties for resins, but does not reach the desired value for controlling the shrinkage of products ( Less than one thousandth), so it cannot be used to produce and manufacture products that require high dimensional accuracy (mainly used in the automotive field)

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