Production of solvent-free polyacrylate melt adhesives is effected continuously, with polymerization followed by extrusion to remove and recycle the solvent

摘要

Continuous, 2-stage polymer-protective production of solvent-free polyacrylate melt adhesives is effected with re-use of the solvent and use extrusion stages. Continuous, 2-stage production polymer-protective production of solvent-free polyacrylate melt adhesives with re-use of the solvent comprises polymerization of a polyacrylate to monomer conversion above 99% in presence of a solvent (mixture) with a vapor pressure temperature at 100 Pas below -10degreesC; continuously mixing the polymer solution with additives etc. and pre-warming under increased pressure; concentrating the solution to a solvent content below 0.1 wt.% using an extruder under vacuum at high temperature, the specific energy input for a polyacrylate of average mol. wt. 600000-900000 being below 0.18 kWh/kg and the temperature at the exit for the polyacrylate being no more than 135degreesC; concentrating, collecting and re-using the solvent from the extruder in step (1)at above 80% of the amount used; compounding the solvent-free adhesive with resins, fillers, stabilizers, crosslinkers, etc. in a second extruder operating at below 0.05 kWh/kg with adhesive exit temperature held at at most125degreesC; and passing the solvent-free adhesive to a coating unit.