| 摘要 |
The invention relates to a two-stage method for producing a polyurethane hot-melt adhesive, having the stages of A) reacting at least one polyol with at least one diisocyanate, the NCO/OH ratio being greater than 1.5, in order to obtain a reaction mixture containing an isocyanate-functional polyurethane prepolymer and non-converted diisocyanate and B) reacting the reaction mixture obtained in stage A), said mixture containing the isocyanate-functional polyurethane prepolymer and non-converted diisocyanate, with at least one polyester polyol, the NCO/OH ratio being greater than 3. The obtained hot-melt adhesive can be formulated as an R-40 classification-free and storage- and processing-stable PUR-RHM with a residual monomer content below 1 wt.% and has a good initial strength. |
