How is the development of two types of water-based curing agents progressing?

Epoxy resin coatings have high hardness, good wear resistance, high adhesion and excellent performance of chemicals, and are widely used in the field of coating. Recently, many countries have promulgated environmental regulations to limit volatile organic solvents (VOCs), and the hydration of coatings has become an important trend in the development of coatings. At present, the hydration technology of epoxy resin at home and abroad is mainly divided into emulsification method and salt method 2 categories, emulsification method refers to the direct emulsification of epoxy resin, self-emulsification without emulsification with emulsification agent or water-based epoxy curing agent emulsification; Water-based epoxy curing agent emulsified epoxy resin is the most important water-based technology, which can overcome the shortcomings of other water-based methods. The principle of water-based epoxy curing agent change is to change polyamine, basically around type I water-based epoxy curing agent, type II.type water-based epoxy curing agent.
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Experts
the development of this "two-type" water-based epoxy curing agent. Regarding type I water-based epoxy curing agent, the expert said that water-based curing agent and water-based epoxy technology are developed simultaneously, for type I water-based epoxy system, the curing agent is required to have both curing function and emulsification function, the first successful development of the industrial water-based epoxy curing agent is Thomas Swan's Casmide360, and its modified product Casmide362. Early use of alamide polyamine as a curing agent of type I water-based epoxy system, although it can make liquid epoxy emulsified but after curing performance is poor, water resistance and chemical resistance is poor, it needs to be modified to ensure that the cured performance close to solvent-based epoxy resin coating.
Because of the short application period of the emulsified epoxy resin system of polyamide curing agent, the softness of the cured coating film is poor, the impact performance is poor, the disadvantage of the coating film brittleness, the performance of the modified polyamide-type curing agent is still not ideal, so the curing agent used for type I water-based epoxy system is mainly polyamine epoxy. Most of the commonly used Type I hydroponic epoxy curing agents are polyamine curing agents to expand the chain, branching, salt, in the molecule to attract non-polar genes, making it a hydro-dispersive curing agent with a pro-epoxy molecular structure, at the same time, it as an cation emulsizer emulsifying epoxy resin, the two groups can be mixed into a stable emulsion, currently using more modified polyamine curing agent is epoxy-polyamine added. The preparation methods commonly used in epoxy modified polyamine curing agents are generally divided into two kinds: using polyethylene polyamine and monoeethylene or polyenoxygen compounds to add, to close about 60% of beamine hydrogen, and then with bisphenol A epoxy to add to it, to achieve appropriate hydrophedica balance, and then react with formaldehyde to further hydroxygenation of bethamide. This curing agent cured epoxy system has a better luster, hardness and chemical resistance, in the case of polyamine excess with bisphenol A epoxy, and then with adipose monocyclic oxygen or aromatic monocyclic oxygen compound closed beamine hydrogen, synthesis with water or water-soluble organic solvent dilution, the resulting addition as a clarification solution, and finally added with acetate neutral part of the amine hydrogen. Such as Shimp and other low-molecular mass epoxy resin, with polyethylene polyamine reaction to produce polyamine epoxy add-on, and then by monoeoxygen compounds to seal its end, and with acetic acid and part of the mid-amine, in order to regulate the curing agent HLB and reduce the reaction activity of the curing agent, extend the applicable period.
later developed a number of new type I water-based curing agent technology, do not need to use organic acid into salts, such as Stark and other use of epoxy resin and excessive inter-benzodiamethyne, reaction generation end epoxyamine addition, and then with end-oxycodol reaction to produce aamideamine, and then sealed to the type of water-based epoxy curing agent. Since the epoxy resin in type II. water-based epoxy resin system has been pre-arranged into emulsion, no water-based epoxy curing agent is required to emulsify epoxy resin, so it only needs to have the function of crosslinker. II. The modified characteristics of type II. Type A water-based epoxy curing agent are similar to that of type I water-based epoxy curing agents, such as polyamide resins reacting with acetate, phosphoric acid or hydrochloric acid to obtain ammonium salts, and then dissolving in water with the aid of alcohol ether solvents to obtain modified polyamide curing agents. Currently in use, type II. Hydro-epoxy curing agents are mainly fatty amines embedded in hydro-hydro-polyoxyethylene chain segments, or epoxy-type curing agents produced by shrinking glyceline ethers in response to epoxy resins or polyethylene polyamines, or with two Polyacid reaction produces polyamide-type curing agent, which uses the hydrophobicity of the polyoxyethylene chain segment to make the curing agent can be stable dispersed in water, while the use of epoxy resin as a chaining agent can improve the compatible between curing agent and epoxy resin. Such as Klein using polyoxyethylene di-shrinking glycerin ether, and bisphenol A epoxy resin reaction to obtain epoxy resin self-dispersion, and then with polyoxypropylene diamine and isofone diamine reaction to produce epoxy monoamine-type curing agent; Phenol A epoxy resin, polyoxyethylene di-shrinking glyceline ether and bisphenol A react to epoxy resin dispersion, and then with polyethylene polyamine reaction to produce end-amine-based epoxy polyamine addition, and finally by sealing the end to obtain type II. hydro-epoxy curing agent.
amphetamine is aromatic amine, but it is involved in curing with the properties of fatamine, so some type II. hydroxycide curing agent is also a modified product of methylhamide. For example, Mitsubishi Corporation of Japan uses methylamine and epoxy chloropropane to produce epoxy-amine supplements under the action of sodium hydroxide, which is used as a water-based epoxy curing agent with excellent performance. Mitsubishi then responded to G-328 with binary pyric acid to obtain a polyamide-based curing agent. There are also the use of lipopamine modified products as a water-based epoxy curing agent, such as Vincent and other fatty amine and epoxy resin reaction to produce end epoxy compounds, and then with a lipid cyclamine (PACM) reaction to make curing agent. Ciba studied a new type II. hydro-epoxy curing agent, a low-activity curing agent is a water-soluble epoxy-amine addition, and a highly active curing agent is a modified water-soluble epoxy-amine addition, through the ratio of 2 to regulate the reaction activity of the curing agent. It does not require the use of polymeric solvents for O-VOC epoxy coatings made from solid epoxy dispersions, while traditional TYPE II water-based epoxy systems require human-built polymeric solvents to reduce the polymerity of resin tgs to benefit the polymerification of resin particles, which brings in volatile organic solvents. This new type II. water-based epoxy curing agent solves this problem.。