The Research And Application Of Automobile Inner Decorating Adhesives

In order to meet the needs of society and the development of environmental protection environmental automobile inner decorating adhesives have been necessary. Therefore, Acrylate emulsion adhesive and one component moisture curing polyurethane hot-melt adhesive(PUR) were studied in this thesis to replace traditional solvent-based adhesives for automobile inner decorating.Acrylate emulsion adhesive was prepared with pre-emulsified and seed emulsion polymerization technology. Glass transition temperature(Tg), types of hard monomers, functional monomers, tackifying resin and other factors were studied and the application of acrylate emulsion adhesive for automobile inner decorating was researched at the same time. The experimentsal results showed that the emulsion pressure sensitive adhesive(PSA) , which was prepared with pre-emulsified and seed emulsion polymerization technology, was provided with low viscosity and good polymerization stability. The emulsion PSA was prepared with the best performance in the condition that Tg of polymer -50℃, styrene(St) as the hard monomer, amount of hydroxyethyl acrylate(2-HEA) about 3%(wt%), the dosage of water-based rosin tackifier 5%(wt%). The properties were as follows: viscosity was 155 mPa·s, tack was 9(steel-ball number), holding power was over 48 h, 180°peel adhesion was 18.35 N/25mm.In order to synthesize high stripping PSA the amount and Tg of seed emulsion were studied and this acrylate emulsion was modified with organic silicon KH-570 at the same time. The results indicated that peel adhesion was improved with organic silicon KH-570; with the dosage and Tg of seed latex increased gradually, the peel strength of emulsion PSA was improved but the transparent of the dry film was changer worse and worse. Optimum formula for emulsion PSA was got with 1.0%(wt%) organic silicon KH-570, Tg of seed latex -50℃and the dosage of seed latex 15%(wt%).The methods of eliminate the residual monomer and irritating odor were discussed in this paper, and various post-processing methods were also comparied. The residual monomer of acrylic emulsion could be eliminated by using tert-butyl hydrogen peroxide and formaldehyde sodium bisulfate as a redox additional initiator, at the same time appropriate amount of ferrous ions was used as the catalyst.The PUR for automobile inner decorating was also studied in this article. The factors such as isocyanate index, the types of polyol and catalyst which influenced the performance of this adhesive were disscused. The results showed that the PUR had the good integration performance including 120℃melt viscosity at 2400 mPa·s, open time at 55 s, initial bond strength at 2.9 N/25mm, 48 h ultimate bond strength at 8.9 N/25mm when PBA was used as main material and isocyanate index was 1.8; the use of dibutyltin dilaurate(T-12) and catalyst A could speed up the curing rate of the PUR significantly, after curing 12 h the PUR achieved the ultimate bond strength as their dosage was 0.05% respectively of total polios(wt%). While the DSC analysis of PUR showed that PUR had no Tg but the process from crystal to liquid phase, so DSC curve could be used as the melting temperature or melting point for PUR.