Patent ID: 7875221

Claim:
A method for the continuous extrusion of an adhesive formulation comprising rubber ( 20 ), a hydrocarbon resin ( 22 ), and a solvent ( 26 ), which method comprises the following steps: providing a dual screw extruder; introducing the rubber and the resin into the dual screw extruder at an initial section thereof; adding at least a fraction of the solvent ( 26 ) at a point of the extruder ( 10 ) that is downstream of the initial section; controlling the temperature of the extruder such that the rubber and the resin are dissolved in the solvent to produce a composition and such that at the outlet of the extruder ( 10 ) the temperature of the composition is less than the boiling point of the solvent ( 26 ) whereby the composition is the adhesive formulation in which the resin and rubber are dissolved in the solvent such that the adhesive formulation has tackifying properties; and extruding the composition, wherein the portion of the extruder ( 10 ) that is upstream of the point at which the first addition of solvent ( 26 ) is performed, the temperature is kept within a range of between 60° C. and 120° C. whereas, in the portion of the extruder ( 10 ) that is downstream of the point at which the first addition of solvent ( 26 ) is performed, the temperature is kept within a range of between 40° C. and 80° C., the temperature in the upstream portion being greater than that prevailing in the downstream portion.