Study On The Synthesis And Performances Of Water-Soluble Polyurethane Sizes

Through the polymerization method, a series of water-soluble polyurethane (WPU) with different molecular structures was prepared from toluene diisocyanate, hexamethylene diisocyanate, polypropylene glycol, dimethylol propionic acid, ethylenediamine, glycol, n-butanediol and n-hexanediol and the structures were characterized by the FT-IR and 1H-NMR. Then the basic properties of WPU, such as viscosity of sizing paste, adhesion to polyester fibers and mechanical performances of sizing film, were investigated. Based on the properties of WPU, the internal relationship between sizing performance and molecular structure of WPU sizes was revealed and references for the study and the application of WPU in warp sizing were provided.In order to make the WPU used as sizing agent meet basic application requirements, the WPU was first endowed with water-solubility or water-dispersibility. This paper chosen dimethylol propionic acid as hydrophilic monomer and studied the influence of its content on the application performances of WPU sizes. The results showed that, when the molar ratio of dimethylolpropionic acid was 30%, the WPU sizes showed good application performances. In order to investigate the influence of chain extenders on application performances of the WPU sizes, a series of WPUs were synthesized using ethylenediamine, glycol, n-butanediol, and n-hexanediol as chain extenders, respectively. The results indicated that WPU sizes using n-butanediol as chain extender had the best application performance. Then the influence of molar ratio of soft segment to hard segment on the performances of the WPU sizes was studied by adopting polyethylene glycol as soft segment. The results showed that, when the molar ratio was 30%, the application performances were better. In addition, WPU sizes prepared from the toluene diisocyanate and hexamethylene diisocyanate, respectively, were researched to study their application performances. Compared to the WPU including hexamethylene diisocyanate, the one including toluene diisocyanate had better performances. The WPU with better performances could be prepared by adopting toluene diisocyanate and n-butanediol, and the monomer proportion of toluene diisocyanate, polypropylene glycol, dimethylol propionic acid, and n-butanediol were 1.05 / 0.30 / 0.30 /0.40.In view of the advantages of WPU such as high toughness and good adhesion, this paper blended the WPU with starch adopting different weight ratios. On the basis of the mechanical properties of the blending sizing film and the adhesion of the blended sizes to polyester fibers, the results showed that when blends contained 10 wt % ~ 15 wt % of WPU, the mechanical properties of the film and the adhesion of the blended sizes were the best.