Patent ID: 6527899
Filing Date: 2003-03-04
Classification: B29C,B32B

Abstract:
Process for producing a pressure-sensitive double-sided adhesive tape, comprising the steps of, in order:a) introducing into a screw extruder a ready-made rubber-based backing material, and processing at temperatures below the melting point of the backing material, wherein 1. the backing material is heated by means of heating elements present on the screw extruder, 2. in a degassing zone, the backing material is freed from volatile constituents by means of an application of reduced pressure, 3. the backing material is homogenized and brought to an intended temperature, b) in a co-extrusion adapter, a barrier layer conveyed by means of a melting and conveying unit is placed onto the backing material on both sides of the backing material, the barrier layer being chosen as a material which has the ability to prevent substances migrating from the backing material into an adhesive layer, c) a resulting intermediate laminate is supplied to a three-channel slot die and is uniformly extruded in web form, d) in the said three-channel slot die a pressure-sensitive hotmelt adhesive, supplied in each case with the aid of an appropriate melting and conveying unit, is applied, top and bottom, over a whole area of the intermediate laminate, e) an adhesive tape thus produced is placed onto an antiadhesive substrate, f) optionally, the adhesive tape is cooled and crosslinked, and wherein a viscosity ratio of backing material to the barrier layer does not exceed 5 and a viscosity ratio of backing matenal to hotmelt pressure-sensitive adhesive does not exceed 10.