What is the hardener? What is the frequently used hardener?
Hardener is the main complex material for adhesive. It may react with adhesives through catalyst, in order to make thermoplastic liner resin or active monomer change into networks or high polymer after curing reaction. For better adhesion and mechanical property, hardeners will change the distance between the molecules, shape, heat stability and chemical stability. So it is essential to choose appropriate hardeners.
Various adhesives have different hardeners in construction. For example, the hardeners of epoxy resin are organic amine, organic acid anhydride, imidazoles, high polymers and other modified products. The hardeners of acrylic ester are redox system formed by organic peroxide and organic nitrogen.In addition, the hardeners of unsaturated polyester resin are organic peroxide and metal salt, while the hardeners of rubber are numerous vulcanizing agents including metal oxide and sulfur. Some cure depending on the vapor in the air, such as silicone rubber sealant, polyurethane adhesive and cyanoacrylate adhesive. All in all, users need to choose appropriate hardeners according to different adhesives.