High viscosity - fine epoxy resin is another high

Refinement is an important development direction of epoxy resin. During the refinement of epoxy resin, “two highs” is an important content, one is high purity and the other is high viscosity. High viscosity, which is high molecular weight, high molecular weight epoxy resin has important application value in the coatings and other fields.

At present, the domestic production method of high molecular weight epoxy resin adopts two-step method, which is generally based on liquid low molecular weight epoxy resin and bisphenol A re-polymerized under the action of the catalyst. Among them, high-purity epichlorohydrin and bisphenol A must be used in the manufacture of liquid low-molecular-weight epoxy resins. The process must be strictly controlled, and the alkali and salts in the resin should be washed to minimize the content of inorganic chlorine and organic chlorine. In this process, the catalyst plays an important role, and the catalysts used are roughly divided into three categories: basic compounds such as sodium hydroxide, aluminum hydroxide, hexahydropyridine, inorganic salt compounds such as aluminum chloride, potassium iodide, etc. Organophosphine compounds such as triphenylphosphine, tributylphosphine, quaternary phosphonium salts and the like.

In epoxy/phenolic resin coating products, commonly used high molecular weight epoxy resins are 607# (Epikote 1007), 609# (Epiklte 1009). Although generally low molecular weight or medium molecular weight epoxy resins can also be used, the chemical resistance, toughness, and bactericidal power of the epoxy/phenolic resin coatings they form are difficult to meet. For food can coatings, epoxy resin is required to have a certain amount of long-chain structure, but also a certain amount of branched chain structure, but also requires a more concentrated molecular weight distribution, in which the lower the content of low-molecular-weight epoxy resin, the better, but not tolerate Colloidal particle generation. Only such an epoxy resin can form a multi-layer network structure with a phenolic resin at a high temperature, and cures quickly and uniformly.

Reprinted from: Ke Yin Network