Synthesis Of Waterborne Polyurethane With Crosslinking Modification And Application In PU/PVC Fabric

Synthetic leather of PU/PVC was new developing materials in recent ten years,it is based on ordinary PVC synthetic leather, using PVC paste resin as the middle foam layer, using waterborne polyurethane fabric as the surface layer, while using waterborne polyurethane adhesion to laminate with fabric. This composite material persist the abrasion resistance, low temperature folding resistance and excellent texture of PU materials, however PVC materials accounted more than 80% solid content and combined two type of PU/PVC material advantages. In addition, PU fabric and PU adhesion both have a strong sealing and barrier function, preventing the plasticizer of PVC middle layer migration. However, the majority of domestic and foreign public patent is based on polyether polyol , poly adipic acid series polyester polyol and polyisocyanate for synthesis of raw materials, the raw materials for the synthesis of complex reactions, the need for expensive catalyst, and under normal temperature for wax production should be pre heated, undoubtedly increase processing order and energy consumption. So seeking for low-temperature easy-processed polyol ester and a new environmental as the main initial material,through chemical modification preparation method to prepare waterborne polyurethane emulsion of comprehensive performance, and applied to the PU fabric material, is the direction of this study.A sort of waterborne polyurethane(WPU) with 35% solid content was prepared with isophorone diisocyanate (IPDI), non-crystallizing poly(propylene carbonate)polyols(PPC), 1,6-Hexan-ediol(HDO) and dihydroxy methyl propionic acid (DMPA)as main initial materials, using triethylamine(TEA) as neutralizing agent,ethylenediamine (EDA) as further chain extender, trimethylolpropane (TMP) and epoxy resin(E-44) as cross-linking agents. Then PPC-WPU was characterized by FT-IR, laser particle analyzer and universal testing machine etc. The results showed that when the molar ratio of n(-NCO ) /n(-OH) was 1.5, w(DMPA)=5.8%,w(E-44)=4%, w(TMP)=2%, and the degree of EDA chain extender was 20%, the water absorptivity of PPC-WPU films was 9.8%, the tensile strength was 36.8MPa,the 100% modulus was 6.4Mpa.When the modified crosslinked WPU emulsion was applied to the PU/PVC fabric material, the addition of some aids was necessary to meet the different product properties. In this study, we mainly ues paper transfer method to scraping fabric and discuss the main aids and formulation of PU/PVC fabric materials. Results show that,0.5-1.0% defoaming agent F6, 0.75-1.0% levelling agent F3, 0.5-1.0% stripping agent SI-2046, 0.5-1.0% thickening agent Ps-166, 5-8% aqueous dispersion are coordinate,EP-44 internal crosslinking modified waterborne polyurethane fabric has better wear resistance, heat resistance and water resistance, with no damage to the surface of the release paper transfer. The test results indicated that the PU/PVC fabric also showed no significant decline in mechanical properties after 7-day constant temperature and humidity test at 70? and 95% RH.