Preparation And Application Of Water-Polyurethane Special Paper As Surface Strengthening

With the development of social economy and the improment ofliving standards,the special paper puts forward more demand,especiallyin view of the different application conditions,Because of some specialpaper puts forward new requirements,the surface of the require a highperformance,dry wet strength,glue degrees of anti-tension,folding andprining eligibility,etc.The effect and dominant role of surface sizingagent is a new type of surface sizing products.Polyurethe film withexcellent mechanical properties,wearing resistance,flexibility andchemical resistance and other characteristics.But the water resistanceand the intensity of its coating are poor and the price is high.Acryliccoating shares water reisistance, solveny resistance,adjustablehardness,and low prices. Therefore, by modifying the chain extensionagent on the water-borne polyurethane,consolidate performance of thematerial significantly improved.It has already became an important wayof new water-based polyurethane.The solvent-free anion Polyurethane/Polyurea composite emusionwas prepared by IPDI,PCL-1000,NMP,DMPA,IPDA.The effects of thetotal mole ratiol of-NCO and-OH, the chain extension agent ofIPDA,DETA,EDA,the content of DMPA, and IPDA on performance ofthe emulsions and films were investigate.Their structure,morphologyand performance were characterized by various modern analysismethods.The solvent-free anion Polyurethane/Polyurea composite emusioncan be also used in surface sizing in papermarking industry.The effectsof the content of-NCO and-OH,the content of IPDA,DMPA,andaziridine and the content of PU on performance of paper sizingvalue,fracture-resist degree and tensile strength.Their surfacemorphology was characterized by SEM,and static contact angle were measured.The main results are shown as follows:(1) Through research the synthesis condition of solvent-freeanion Polyurethane/Polyurea composite emulsion. when n（-NCO）： n（-OH）=1.6， w (DMPA)=3.4wt%， w (trithylamine)=3.2wt%， w(DETA)=0.5wt%,the temperature of polyreaction is80℃,the emusionand coating can achieve the optimize performance.(2) The result of film-forming test showed that under the bestsynthesis condition,the mechanical properties and water resistantperformance of the membranes are better,respectively,the hardness wasHB, and water absorption was2.96%.(3) The Fourier transform infrared spectroscopy(FT-IR) indicatedthat the structures of the solvent-free anion Polyurethane/Polyureacomposite emulsion were met the expected. The thermogravimeticanalysis (TGA) indicated that the original decomposition temperature ofthe resin is above150℃，the thermal stabiliy of the membrane is good,and this temperature is fit for general techniques of papermarking. Thewide-angle X-ray diffraction(XRD) diagram showed that the polymer isamorphous polymer, which can satisfy normal use. The particle size andsize distribution of emulsion show that the particle size distribution in anarrow areas. The zeta potential indicates the granule of emulsion wasuniformity, and the system is stable.(4) The solvent-free anion Polyurethane/Polyurea compositeemulsion is used in papermarking as surface sizing agents. The surfacesizing application result showed that the paper’s folding strength was upto125times, the sizing degree and tensile strength are better thanbefore.