Requirements for unsaturated polyester resin in casting molding process

Unsaturated polyester resin castings are required to be free of bubbles, air gaps and cracks. There are two main reasons for residual bubbles and air gaps: one is the introduction of air when adding a large amount of filler. This problem can be solved by extending the vacuum degassing time during the pouring process; the other is unsaturated polyethylene. The presence of low molecular weight volatiles in ester resins can be eliminated in the manufacture of unsaturated polyester resins. Therefore, the molding process has the following requirements for unsaturated polyester resin:
1. The resin must be able to quickly and fully infiltrate the filler evenly, so the viscosity of the resin must be low, usually 0.6~8Pa·s;
2. Resin and pigments have good compatibility, and can be blended into various colors. The colors between batches of products are uniform and the color difference is small to ensure the beauty of the products;
3. Good storage stability, service life is usually 3 to 6 months;
4. For marble resin matrix, the resin should keep the filler in a uniform suspended state until the resin gels;
5. In a production environment, the resin should release heat steadily when curing so that the heat can be released evenly to avoid large thermal stress inside the product, which may cause cracking or micro-cracks in the product. Therefore, the resin must have good reactivity, both It is necessary to form a cross-linked structure and solidify quickly without generating excessive thermal stress;

6. After the resin is cured, it must have good heat resistance and impact resistance. It must not produce excessive internal stress and cause product damage under rapid cooling, rapid heating, and repeated impacts;
7. For unsaturated polyester casting resins used to manufacture imitation wood products such as furniture and floors, the resin is required to be flexible after curing. Generally, the elongation rate of unsaturated polyester resin is required to reach more than 9%;
8. For cast products for indoor and outdoor decoration, the resin is required to have good light stability and not discolor, warp or crack under the influence of sunlight, which may cause damage to the product;
9. The cured product is flame retardant, reaching V0 level, and has low smoke, low toxicity, and low irritation, which can ensure the safety of the product;
10. Convenient source and low price. Choose Zhongtritium – a professional unsaturated resin manufacturer, bringing excellent quality and reliability guarantee.

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