The epoxy resin has a secondary hydroxyl group and an epoxy group, and the secondary hydroxyl group can react with an isocyanate. The epoxy resin is directly added to the hydroxyl group-containing component of the polyurethane adhesive as a polyol. With this method, only the hydroxyl group participates in the reaction, and the epoxy group fails to react.
The epoxy is opened by an acidic resin and a carboxyl group, and then reacted with an isocyanate in the polyurethane adhesive. It is also possible to dissolve the epoxy resin in ethyl acetate, add phosphoric acid to warm the reaction, and add the adduct to the polyurethane adhesive; the initial viscosity of the glue; the heat resistance and the hydrolytic stability can be improved, and the alcohol amine can also be used. Or the amine reacts to form a polyol, and the presence of a tertiary nitrogen atom in the adduct accelerates the NCO reaction.
The use of epoxy resin as a polyhydroxy component combines the advantages of polyurethane and epoxy resin, and has good bonding strength and chemical resistance. The epoxy resin used in the manufacture of polyurethane adhesive generally adopts EP-12 and EP-13. , EP-16 and EP-20 and other varieties.