Pressure-sensitive adhesive strip for moisture-insensitive peelable adhesive bonds

Abstract

The invention relates to a peelable adhesive strip which is coated with a pressure-sensitive adhesive at least one side. Said adhesive strip is constituted of the following layers: a core layer having an elongation at tear of at least 300%, an external carrier layer having an elongation at tear of not more than 120% and at least some sections of which are connected to the core layer in such a manner that it becomes detached from the core layer when the same is stretched, a first adhesive layer at least some sections of which are applied to the side of the external carrier layer and which is opposite the side connected to the core layer.

1 . A redetachable, at least single-sided pressure-sensitive adhesive strip comprising:
 a) a core layer which has a breaking extension of at least 300%,   b) an outer carrier layer which has a breaking extension of not more than 120% and which at least sectionally is connected to the core layer such that it separates from the core layer when the latter is extensionally stretched, and   c) a first adhesive layer which is applied at least sectionally to the side of the outer carrier layer that is opposite the side connected to the core layer.   
     
     
         2 . The adhesive strip of  claim 1 , wherein the core layer is formed from an adhesive which is redetachable by extensional stretching in the bond plane. 
     
     
         3 . The adhesive strip of  claim 1 , wherein the core layer protrudes beyond the outer carrier layer at least in one region. 
     
     
         4 . The adhesive strip of  claim 3 , wherein the protruding region is made nontacky. 
     
     
         5 . The adhesive strip of  claim 1 , wherein the adhesive of the core layer is constructed on the basis of styrene block copolymers. 
     
     
         6 . The adhesive strip of  claim 1 , wherein the core layer is formed by a carrier which is redetachable by extensional stretching in the bond plane. 
     
     
         7 . The adhesive strip of  claim 1 , wherein a further adhesive layer is applied sectionally on a side of the carrier that is opposite the side connected to the outer carrier layer. 
     
     
         8 . The adhesive strip of  claim 6 , wherein between carrier and outer carrier layer there is a second adhesive layer. 
     
     
         9 . The adhesive strip of  claim 8 , wherein the bond strengths of the second adhesive layer and of the further adhesive layer can be reduced by extensional stretching in the bond plane. 
     
     
         10 . The adhesive strip of at least one of  claims 6  to  9 , wherein the carrier protrudes beyond the outer carrier layer at least in one region. 
     
     
         11 . The adhesive strip of  claim 6 , wherein the carrier foam. 
     
     
         12 . The adhesive strip of  claim 1 , wherein the first adhesive layer is based on silicone and is crosslinked. 
     
     
         13 . The adhesive strip of  claim 1 , wherein on the core layer and/or on the further adhesive layer there is, at least sectionally, a second outer carrier layer which separates from the core layer or from the further adhesive layer when the latter is extensionally stretched, and which is provided at least sectionally on the free side with a third adhesive layer. 
     
     
         14 . The adhesive strip of  claim 13 , wherein the outer carrier layer and the second outer carrier layer and/or the first and the third adhesive layers are identical. 
     
     
         15 . The adhesive strip of  claim 1 , wherein the adhesive of the core layer, the further adhesive and/or the third adhesive are composed of block copolymers or of a mixture thereof, especially including polymer blocks formed from vinyl aromatics (A blocks) and those formed by polymerization of 1,3-dienes (B blocks). 
     
     
         16 . The adhesive strip of  claim 15 , wherein the vinyl aromatics are styrene and/or the B blocks are formed by polymerization of butadiene and/or isoprene and/or their hydrogenation products or by polymerization of isobutylene. 
     
     
         17 . (canceled) 
     
     
         18 . A method of separating two substrates bonded with the adhesive strip of  claim 1  comprising stretching the core layer in the direction of the bond plane starting from the region which has been made nonadhesive, until the core layer releases from at least one of the outer carrier layers so that the two substrates are separated from one another and on at least one of the two substrates an outer carrier layer is additionally bonded, and the outer carrier layer together with the first adhesive layer is peeled from the other substrate at an angle of removal of greater than 45°. 
     
     
         19 . The adhesive strip of  claim 8  wherein the second adhesive layer has the same composition as the further adhesive layer.