| This essay is intend to prepare modified epoxy curing agents which have the relatively simple and easy production progress for lowering the cost of company and solving the problem of blanch cured products by systematic experiments and scientific characterization.At first, the alicyclic and polyether amine with small molecular weight were selected as raw materials to conduct modification experiment with E51 epoxy resin after paper review and theoretical analysis. The best mass ratio of TDC modified process is TDC:128 epoxy resin at 100:40(mass ratio) and D230:128 epoxy resin at 100:60(mass ratio). The prepared modified curing agents have relatively good coating hardness and adhesive force, but the operability in the low temperature isn’t good due to the high viscosity.The benzyl alcohol(BA), propylene glycol methyl ether(PM) and propylene glycol methyl ether acetate(PMA) were selected as the solvent to enhance the operability in the low temperature. For TDC modified curing agent and D230 modified curing agent, the viscosity decreased from 1527mPa·s to 1203mPa·s and 1452·s to 1220mPa·s in the 5℃ temperature respectively after 40%(wt%) solvent which is made of BA:PM=7:3(mass ratio) was added. Also, the adhesive force and coating hardness of TDC modified curing agent is 3 level and H level respectively. For D230 modified curing agent, the adhesive force and coating hardness is 2 level and H respectively.Then the influence of reaction temperature and reaction time on the properties of products were investigated and obtained the best production temperature of TDC modified curing agent and D230 modified curing agent respectively. The best dropping temperature and reaction tempearature of TDC modified curing agent is 60℃ and 70℃ respectively, for D230 modified curing agent is 80℃ and 90℃ respectively. The best dropping time and reaction time of TDC modified curing agent is 30 min and 45 min respectively, for D230 modified curing agent is 45 min and 60 min respectively.The properties of curing agents which bought from other companies were compared with the curing agents we prepared in the lab. The results showed that the basic properties of curing agents are almost the same. But the cost of curing agents was decreased heavily when comparing with the curing agents which bought from other companies. Finally, two types of epoxy curing agents were prepared. The TDC modified curing agent is suitable for low humidity environment and relatively low temperature. The D230 modified curing agent is suitable for high humidity and relatively low temperature. |
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