| With the improvement of people's environmental protection awareness,traditional solvent-based epoxy resin varnish suffered serious criticism due to the release of a large number of volatile organic compounds during cured.Its5 range of applications is constantly limited due to the environmental constraints.Therefore the development of no air pollution,safe and non-toxic water-soluble resin is imminent.Water-soluble epoxy resin is attracting much attention because of its excellent performances,such as non-toxic pollution,high hardness,good adhesion and good chemical stability,etc.In this paper,based on two experiment principle,two kinds of water-soluble epoxy resins,which denoted as type ? and?,were obtained by using the toluene diisocyanate and dimethylol propionic acid to modified the E-44 epoxy resin.The optimum synthesis process for water-soluble epoxy resin was determined by discussing the selection of reaction temperature and reaction time.The structure of epoxy resin was characterized by infrared spectroscopy.Then the two kinds of silicon steel sheet varnish with two kinds of water-soluble epoxy resin as the matrix,the neutralizing agent and curing agent as additives were prepared.The effect of the neutralizing agent and the curing agent on the performance of the silicon steel sheet varnish was discussed.At last,the performance differences of the two kinds of silicon steel sheet varnish were compared and analyzed.To water-soluble epoxy resin varnish type ? results indicated that the best usage content of the neutralizing agent B was 10wt%for the total weight of water-soluble epoxy resin,and the usage content of curing agent B was 25wt%for water-soluble epoxy resin.The solid content of silicon steel sheet varnish was 50wt%.The pH value of vanish was 8,viscosity is 43"(23?,positive-4 cup),gel time is 172"(210?),water-solubility is infinitely dilute.Moreover,the paint films have smooth outlook,and its pencil hardness was 5H,adhesion level was 1.While for the second type water-soluble epoxy resin varnish for silicon steel sheet(type ?),results indicated that the best usage content of neutralizing agent B and curing agent B was 17wt%and 25wt%,respectively.The solid content of silicon steel sheet varnish was 50wt%.The pH value of vanish was 7.5,viscosity is 50"(23? positive-4 cup),gel time is 70"(210?),water-solubility is infinitely dilute.Moreover,the paint films have smooth outlook,and its pencil hardness was 8H,adhesion level was 1.According to the comparative analysis of the above indicators,the type ? water-soluble epoxy resin varnish has a better comprehensive performance than type?and more suitable for coating applications. |
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