Synthesis And Application Study Of Waterborne Polyurethane For Lerther

Waterborne polyurethane(WPU) is dispersibled in water. WPU don not contain organic solvent is a friendly environmental polymer material. As people's awareness on environmental protection enhanced, WPU will replace solvent-based polyurethane and have a rapidly development. WPU leather as a new field of polyurethane has been caused gradually people's value.From reaction material,we searched the synthesis of polyesters and the effects to WPU,throuth crosslinking improved the water-resistence of WPU which could used to leather.In this thesis,polyester was synthesised with adipic acid and diglycol,studied the effect of the reaction time, the percent excess of glycol,the kind and content of of catalyst,vacuum time et al on the reacion.Then the optimal condition of synthesis molecular weight is 2000 was as follows: reaction temperature was 180℃,the content of methanesulfonic acid(as catalyst) was 0.1%,reaction time 3 h,vacuum time 3 h.In this thesis , waterborne polyurethane was prepared by isophorone diisocyanate (IPDI),polyster and dimethylol propinic acid(DMPA). Studied the effect of the conntent of solvent and DMPA,NCO/OH,degree of neutralization and chain-extender on waterborne polyurethane,the results showed that the emulsion is stable with the conntent of solvent is 30%,the content of DMPA between 6% and 8%,NCO/OH between 1.1 and 1.5,the degree of neutralization between 80% and 100%.At the same time ,we inspected the effect of polyesters and polyethers to WPU,found the kind of polylol have great influence to WPU.PPG could improve the elongation.In order to improve the water-resistence ,we add crosslinging agent and epoxy resin .Waterborne polyurethane was modified by epoxy resin(E-51),when the content of E-51 under 20%,we could get stable emulsion and as the incresse of E-51,the water-resistence would improve.Different crosslinking agents had different influence,TMMM and HMMM not only improve the water-resistence but also improve the mechanical properties.Sac-100 could improve the water-resistence ,but would reduce the mechanical properties.Applied our products to the leather ,we found our products have the same capability as products sold in maket.