Acid Anhydride Curing Agent Composition
First, Phthalic acid (PA)
Phthalic anhydride is a traditional curing agent, which is still used in a large amount up to now, which is mainly used in the casting of electrical appliances. Phthalic anhydride is white crystalline with melting point 128, having the most important characteristics of low price, low curing exothermic peak and excellent electrical performance. Phthalic anhydride is easy to sublimate when heated, and needs to be mixed with epoxy resin at a higher temperature, which may lead to shorter service life of the complex. Therefore, special attention must be paid to the use of phthalic anhydride.
Second, Tetrahydrophthalic Anhydride (THPA)
Tetrahydrophthalic anhydride is the addition product of maleic anhydride and butadiene, which is the white solid, having the melting point of 100C. It is difficult to mix with epoxy resin, but it has no sublimation. It can improve the composition of PA large-scale casting formula. It can also be used as curing agent for powder coatings and epoxy resin transfer film plastics. In addition, it can be mixed with phthalic anhydride and hexahydrophthalic anhydride as curing agent. THPA is isomerized to form the following four isomers. The mixture of these four isomers is liquid at room temperature. This type of curing agent is 70 anhydride produced by Tianjin Jindong Chemical Plant.
There are also hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, methyl hexahydrophthalic anhydride, methyl Nadic anhydride, trimellitic anhydride and its modifiers, aliphatic anhydride and aliphatic polyanhydride, trialkyl tetrahydrophthalic anhydride, methyl cyclohexenyl tetrahydroic anhydride, pyromellitic dianhydride, phenylketothalogenated anhydride and halogenated anhydride.
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