Study On Proparation And Grafting Of Moisture Cured Hot Melt Polyurethane Adhesives

In this paper, the moisture curing polyurethane (PUR) hot melt adhesive was prepared by reacting diols with diisocyanates. The effects of reaction temperature, reaction time and material ratio on the performance of PUR were investigated. The optimum synthesis conditions for PUR hot melt adhesive was obtained:Reaction temperature and reaction time were about 85℃ and 2h, respectively. When the molar ratio of polyester/polyether was 6/4, the isocyanate was diphenyl-methane-diisocyanate, the tackifier was acrylate resin, the mass fraction of catalyst, chain extender and filler were 0.8wt%,1.0wt% and 1.2wt%, respectively, the PUR hot melt adhesive showed better performance.Pentaerythriol Diacrylate (PEDA) was synthesized by direct esterification from acrylic acid and pentaerythritol. Technology of HPLC, FT-IR and 1H NMR were used to analyse PEDA qualitatively and quantitatively. PUR hot met adhesive was modified with PEDA. Experimental results show that when PEDA usage was 7wt%, the performance of opening time, bonding strength and melt viscosity for PUR hot melt adhesive was the best.TGA and PY-GC/MS were used to study the difference of sample’s thermal behavior which existed before and after crosslinking reaction. Low temperature pyrolysis showed original molecular conformation, and constituted the fragmentation of a large number of "fingerprint", pyrolysis in higher temperature tend to repeat segment fracture. Pyrolysis was along an order of phthalic anhydride polyester polyols, MDI, aliphatic polyester polyols.