Study On Synthesis And Modification Of Acrylic Emulsion Adhesive

In this paper, the study actuality at home and abroad of acrylic emulsion adhesives’preparation and modification were reviewed. At first, the comparison of four polymerizationtechniques and the optimization of experimental conditions as the basis, acrylic emulsionadhesive was synthesized by semi-continuous technology with all the monomers werepre-emulsificated. And discussed the effects of the functional monomer, emulsifier andinitiator dosage, solid content on the properties of emulsion. The optimized conditions weredetermined as follows: The dosage of alpha methyl-acrylic acid was9%; the mass ratio ofSDBS and OP-10was from1:2to3:2; the dosage of emulsifier was3.5%; the dosage ofinitiator was0.3%of the total system; the theory solid content was40%. The structure ofacrylic, particle size, thermal stability and corrosion resistance were characterized byFourier transform infrared spectrum, X-ray diffractometer, scanning electron microscope,granulometer, thermogravimetric analyzer and electrochemical workstation, respectively.The results showed that the stability and corrosion resistance of the optimized acrylicemulsion adhesive were improved.Secondly, in view of the shortage of acrylic emulsion adhesives, we modified acrylicemulsion adhesives by using modifiers which were three kinds of silicone monomer. Andwe discussed the effects of polymerization temperature, stirring intensity, pH value, siliconmonomer adding way and different types of silicon monomer on the modification reaction.Respective optimal condition was as follows: the temperature was from80℃to85℃;thestirring rate was from250rad/min to400rad/min; adjust pH in the early stage of thereaction by adding NaHCO3, its content was from1.5%to2.0%; the putting way of siliconmonomer was late to join; modified individually, the best dosage of D4was from4%to10%;the best dosage of KH570was from1%to2%; the best dosage of A-171was from0.5%to2.0%.Finally, the acrylic emulsion adhesive was modified by D4and KH570with chemicalprocess. we obtained the main technological parameters via orthogonal experiment. And westudied the effect of compound modifier content on product. Then we get the modifiedproduct successfully. The loss of C=C bond and the appear of Si-O-Si,-Si(R)2O-bonds inthe infrared spectrum as evidence, X-ray and particle size analysis as an auxiliary proof,double silicon had grated onto the copolymer molecules; and played a synergy. SEManalysis showed that toughness of the modified latex film was better than the unmodified one. According to the analysis of thermogravimetric apparatus,42%of material frommodified product in500℃didn’t break down, but the unmodified product just had7%.According to the analysis of EDS, it illustrated that the waterproof of modified product wasimproved when the silicon was enriched on the surface of the film. Compared themacroscopic properties of unmodified and modified products. The results showed that whenm(D4):m(KH570) was2:1, the dosage of emulsifier was3.0%, the dosage of KPS was4.0%,the monomer(soft and hard) ratio was1:1, double siloxane content was3%, the stability ofthe acrylic emulsion adhesive modified by little double siloxane was good, and its viscosity,water resistance, heat resistance and adhesive performance were improved greatly.