Epoxy resin production process
The production process of bisphenol A epoxy resin is generally divided into one-step method and two-step method.
The one-step method is to directly react bisphenol A with epichlorohydrin to prepare epoxy resin, which is commonly used in the synthesis of low and medium molecular weight epoxy resins; the two-step method is to continue the reaction of low molecular weight resin with bisphenol A. High molecular weight epoxy resins can be synthesized in one step or in a two-step process.
Production process of liquid bisphenol A epoxy resin
The one-step process is a polycondensation of bisphenol A and epichlorohydrin under the action of NaOH, that is, the ring opening and ring closure reactions are carried out under the same reaction conditions. At present, the domestic E-44 epoxy resin is synthesized by a one-step process.
The two-step process is the reaction of bisphenol A and epichlorohydrin under the action of a catalyst (such as a quaternary ammonium salt), the first step by an addition reaction to form a diphenol-propane chlorohydrin ether intermediate, and the second step is carried out in the presence of NaOH. A closed loop reaction produces an epoxy resin. The advantages of the two-step method are: short reaction time; stable operation, small temperature fluctuation, easy to control; short alkali addition time, can avoid large-scale hydrolysis of epichlorohydrin; product quality is good and stable, and the yield is high. The domestic E-51 and E-54 epoxy resins are synthesized by a two-step process.
Production process of solid bisphenol A epoxy resin
The one-step method (known abroad as the Taffy method) can be divided into a water washing method, a solvent extraction method and a solvent method, which is a polycondensation reaction of bisphenol A and epichlorohydrin under the action of NaOH for producing a medium molecular weight solid epoxy resin. Domestically produced E-20, E-14, E-12 and other epoxy resins are basically used in this method.
The two-step method (referred to as the Advancement method in foreign countries) can be divided into a bulk polymerization method and a catalytic polymerization method. After the low molecular weight liquid E-type epoxy resin and bisphenol A are heated and dissolved, the addition reaction is carried out under the action of a high temperature or a catalyst. Continuously expanding the chain, and finally forming a high molecular weight solid epoxy resin, domestically produced E-10, E-06, E-03 and other epoxy resins are used in this way.
QuanZhou Neweco High Polymer Material Co.,Ltd.
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