Rsearch On Preparation And Performance Of Modified Waterborne Polyurethane Self-matting Resin

According to people’s aesthetic concepts and environmental awareness,the matting waterborne polyurethane coating has both environmental protection and high-grade color,so it is loved by the public.In order to avoid the defects such as incompatibility of matting agent and resin,unstable emulsion,and friction resistance of the coating caused by matting coatings prepared by commonly added matting agents,study on self-matting waterborne polyurethane without matting agents and targeting Its disadvantages such as poor matting performance,poor mechanical properties,and slightly poor water resistance has been modified.In this experiment,a series of self-matting resins with better properties were prepared.The specific research plan and research results are as follows:（1）The first chapter of the thesis introduces the monomers of synthetic waterborne polyurethane,the preparation,structure and performance of waterborne polyurethane,introduces the matting waterborne polyurethane coating and the principle of matting,and finally gives an overview of self-matting waterborne polyurethane and its modification.（2）The second chapter of the thesis was based on poly（1,4-butanediol adipate）（PBA）,isophorone diisocyanate（IPDI）,dimethylolpropionic acid（DMPA）,1,4-butanediol（BDO）and hydroxypropyl terminated polydimethylsiloxane（PDMS）.Then,a series of silicone-containing self-matting waterborne polyurethane emulsions were synthesized with triethylamine（TEA）as neutralizer and ethylene diamine（EDA）as post chain extender by addition of epoxy resin into the polyurethane prepolymer.The particle size of emulsion was measured by particle size analyzer.The films were characterized by FTIR and SEM.The properties such as 60°gloss,water contact angle and thermodynamics of the films were analyzed.The results indicated that under the conditions of n（PBA）∶n（PDMS）=1∶2,additive amount of epoxy resin E-51 of 5.0%（based on the total mass of the prepolymer,the same below）,the particle size of the prepared emulsion was 1152 nm,the 60°gloss and the average water contact angle of the corresponding film was 3.4 and 107.3°.Furthermore,the film showed the best hydrophobicity and mechanical properties.The tensile strength was 24.42 MPa and the elongation at break was 362%.The thermal decomposition temperature at 50%mass loss of this film was 18.3℃higher than that of the unmodified polyurethane film.（3）The third chapter of the thesis uses trimethylolpropane（TMP）as the crosslinking agent,and sulfonate grafted polyester diol（BY3305B）and poly（1,4-butanediol adipate）（PBA）as the soft segment,Synthesized cross-linked sulfonate type waterborne polyurethane self-matting resin without matting agent.Characterized by scanning electron microscopy（SEM）,Malvern laser particle size analyzer（DLS）,Fourier infrared spectroscopy（FT-IR）and other tests,and analyzed the 60°gloss and water contact angle and thermodynamics of the films were analyzed.The results show that when the amount of crosslinking agent added was 0.75%,the particle size was about 1965 nm,the emulsion was opaque,the film gloss（60°）can reach 1.2,and the matting effect was achieved;the water contact angle was 107.9°,and the film water absorption rate was 2.9%,the hydrophobic performance was the best;the tensile strength of the film was22.9 MPa.（4）The fourth chapter of the thesis was to synthesize polymer hollow microspheres through the miniemulsion method.The surface of the microspheres was modified with amino groups and mixed with poly（1,4-butanediol adipate）（PBA）and isophorone.Isocyanate（IPDI）,dimethylolpropionic acid（DMPA）,and 1,4-butanediol（BDO）were monomers to synthesize polyurethane prepolymers and react to obtain a waterborne polyurethane matting resin modified by polymer hollow microspheres.Use thermogravimetric（TG）,Fourier infrared（FT-IR）,scanning electron microscope（SEM）,60°gloss meter and other tests for characterization.The results show that the surface of the polyurethane film prepared when the R value was 1.45 and W_DMPA/%was 6.5%,the gloss（60°）measured by the gloss meter was 1.6,indicating that the prepared film conforms to the extinction mechanism.The water contact angle was 91°,and the hydrophobic performance was better;the tensile strength of the film can reach 16.3 MPa,and the elongation at break was 331.6%;thermogravimetric analysis shows that the polymer hollow microsphere modified water-based polyurethane self-matting resin adhesive Compared with the thermal decomposition temperature of the unmodified WPU film at 50%weight loss,the thermal stability of the film increased by 15.9℃,indicating that the thermal stability was improved after modification.