Epoxy value is the most important indicator to identify the quality of resin, and it is also the basis for calculating the amount of curing agent. The reciprocal of the epoxy value multiplied by 100 is called "epoxy equivalent". "Epoxy equivalent" means grams of epoxy resin containing one gram equivalent.
The curing agents used in epoxy resins mainly include polyamines, acid drunks, miwas and resins. In addition, there are low-toxic curing agents, latent curing agents, and low-temperature curing agents. The main advantages of epoxy resin are.
(1) Excellent bonding performance. Because epoxy resin has a variety of polar groups (light group, ether group and epoxy group), at the same time, epoxy group can form a chemical bond with glass fiber. Therefore, epoxy resin has the best bonding performance and is called “universal adhesive”. It has outstanding adhesion to metals, ceramics, glass, and wood. It is used to make glass fiber reinforced plastic products with high strength, and is especially suitable for the bonding of glass fiber reinforced plastics. Mixing epoxy resin with unsaturated polyester resin and curing at room temperature or heating can improve strength and performance.
(2) Low curing shrinkage. When the epoxy resin is cured, no small molecules are formed, so the shrinkage rate is small.
(3) Good temperature resistance. The heat distortion temperature is higher than that of general-purpose polyacids. Changing the curing agent can also greatly increase the heat distortion temperature.
(4) Variety. Epoxy resins have a wide variety of resins, curing agents and modification systems according to different needs. It can range from very low viscosity to high melting point solids