Industry news: The unsaturated polyester resins produced by manufacturers of all sizes in my country are mainly o-phthalic polyesters with less m-benzene type. One of the reasons is that the synthesis time of isophthalic polyester is longer, and the raw material isophthalic acid contains a certain amount of terephthalic acid, which is extremely difficult to react without catalyst. Tang Siding et al. used a mixed catalyst of organometallic salt and organometallic compound to synthesize m-benzene-type unsaturated polyester resin in a relatively short period of time. The resin has good resistance to boiling water, chemical corrosion and physical and mechanical properties.
M-benzene type unsaturated polyester resin is one of the main varieties of corrosion-resistant unsaturated polyester resins, and it has become a more general medium corrosion-resistant resin because of its ease of manufacturing, low cost, and resistance to weak acids and various solvents. The basic raw materials of isophthalic unsaturated polyester resins are isophthalic acid, maleic anhydride, and propylene glycol. Changing the ratio of the three raw materials will result in a certain change in corrosion resistance. Using neopentyl alcohol instead of propylene glycol has Better weather resistance and water resistance.
In the main chain of the m-benzene type unsaturated polyester resin molecule, because two ester groups are far apart, the space effect is small, and it has excellent physical and chemical properties. They have high strength, good toughness, water resistance, weather resistance, and corrosion resistance, and are the most commonly used resins for high-performance FRP/composite materials. At present, in the international market, m-benzene unsaturated polyester resin has become a general-purpose resin, such as American EASTMAN company, REICHOLD company, British SCOT BADER company, Dutch DSM company, Japanese catalyst company, these companies have produced m-benzene polyester It accounts for 1/4 of the total polyester. Resin grades imported from the United States by Nanjing Insulation Materials Factory, among which polyester grades resistant to chemical corrosion account for 80% of the isophthalic type and 50% of the gel coat resins.
The m-benzene type unsaturated polyester resin is widely used in industries such as ships, sanitary ware, urban water supply facilities and sewage treatment equipment. In some special industries, the application of m-benzene type unsaturated polyester resin is also under study. In the paper industry, Yang Jianqiao and others studied the corrosion characteristics of m-benzene unsaturated polyester resin in H202 at different temperatures and concentrations. The results show that it has good corrosion resistance in H202 and can be used as H202 distillation equipment And corrosion-resistant materials for bleaching equipment. Chao Huairui  studied the corrosion behavior of benzene-type unsaturated polyester resin in aqueous solution of chlorine dioxide. The corrosion behavior was analyzed by using infrared spectroscopy, scanning electron microscopy and other analytical methods. The results showed that the m-benzene-type unsaturated polymer Ester resins mainly undergo physical changes in the chlorine dioxide aqueous solution. They have good corrosion resistance and can be used for the protection of the chlorine dioxide bleaching system in the paper industry. These studies have expanded the application field of m-benzene unsaturated polyester resin.