Preparation Of Solvent-free Cationic Silicone Modified Polyurethane/polyacrylate Composite Emulsion And Its Applied

As is known to all, water-borne polyurethane coatings has good abrasionresistance, mechanical properties and chemical resistance character andcharacteristics of flexibility, but at the same time its coating has low intensity,and water resistance is bad, the price is high. Acrylic resin coatings has goodsolvent resistance, good water resistance, hardness is adjustable, and the price ischeap. So, PU and PA can be complementary in performance, PUA emulsionpolymerization can overcome their shortcomings, obviously improve theperformance of the emulsion and the coatings. But there also are some defects.After modified by organic silicone, not only can further improve the waterresistance and weather resistance, acid-proof alkaline, and because organicsilicon in the coatings surface enrichment, making it also has good mechanicalproperties. After polyurethane become prepolymer, then the crosslinkingmodification, increasing its molecular weight and can make the molecularstructure network more dense, enhancing its surface sizing degrees andmechanical properties. The experiment is prepared in this system: isophorone diisocyanate(IPDI),polytetrahydrofuran glycol(PTMG1000), N-methyldiethanolamine(MDEA),trimethylolpropane(TMP), silane coupling agent (KH550) as the main rawmaterial, butyl acrylic(BA) and styrene (St) as the reaction medium, togradually polymerization firstly, formed the cationic prepolymerization sealedby–NCO. Then in the polymer with hydroxyl ethyl methacrylate, free radicalscopolymerization, eventually forming copolymer emulsion.Researching the emulsion and the membrane performance are impacted bythe content of MDEA,HEAand organic silicon. Use the analysis instrument ofseveral modern instrument to characterizate its form, structure and thermalstability.This study also Discuss the organic silicone modified solvent free cationicpolyurethane/acrylate emulsion Of practical application in paper surface sizingeffect. Paper surface sizing before and after using scanning electron microscopy(SEM) characterized.The results of the study show that:(1) through to the organic silicone modified solvent free cationicpolyurethane/acrylic ester (PUA) emulsion synthetic conditions of research,good synthesis process for: n (NCO): n (OH)=1.07, m (St): m (BA)=1:2, w(MDEA)=5.50%, w (TMP)=0.55%, w (KH550)=0.69%. The emulsioncopolymerization method, through the silane coupling agent KH550 modification, preparation is a solvent cation type have expected structure of thepolyurethane.(2) infrared spectrometry (characterized by ft-ir analysis shows that thepreparation of organic silicon modified solvent free cationicpolyurethane/acrylate emulsion has expected chemical structure. Transmissionelectron microscopy (TEM) show that latex analysis of spherical shapedistribution, particle surface smooth, particle distribution relatively uniform;Thermogravimetric analysis (TG) show that adding organic silicon singles later,emulsion membrane of heat stability can be improved; X-ray diffraction (XRD)show that adding organic silicon singles, the crystallinity of emulsion membrane,reduced.(3) at the same time, organic silicon to join, increase flexibility in the filmat the same time, improve the emulsion film water resistance and mechanicalproperties. As organic silicon to join the contact Angle°increases to113.59from78.89°, elongation at break increased from590.536%to907.680%.Last,discuss its preparation and using about KH570modified solvent-freecationic Polyurethane/polyacrylate composite emulsion.