Study On Improving Environmental Performance Of Furan Resin Modified By Urea-Formaldehyde

Furan resin modified by urea-formaldehyde is widely used in foundry production as a kind of adhesive, which is the largest condensation in furan resin series. However, it still exists the problem of high free formaldehyde in the process of application; therefore, it’s the common goal for foundry materials researchers to synthesize a kind of urea-formaldehyde furan resin with low free formaldehyde and good performance.The main objective of this thesis is to synthesize furan resin modified by urea-formaldehyde with low free formaldehyde and excellent performance by using formaldehyde, urea and furfuyl alcohol. Studying on the optimal synthetic technique of and then studying the modification of it by using different materials. Exploring different process conditions on the tensile strength, free formaldehyde, viscosity and studying modification mechanism of different kind of modified materials and its impact on the comprehensive performance of the furan resin.Several conclusions are obtained:the optimum condition was determined:(1)the F/U molar ratio was 2.4:1, in addition reaction stage, the pH was 6.0, the reaction temperature was 80 ℃ for about 90min, the dehydration amount was 65%, in the co-condensation stage, the pH was 3.8 and the two times of furfuyl alcohol addition ratio was 1:2.5;(2)On this basis, furthermore, when adding 0.4% PVA in co-condensation reaction made the tensile strength increase by 13.9% and free formaldehyde decrease by 38.4%, the comprehensive performance of resin reach the national second class goods index;(3)Adding 1.5% surface modified nano-silica made tensile strength increase by 17% and free formaldehyde decrease by 59%, the comprehensive performance parameters of resin exceed the national first class goods index.