Reversible pressure-sensitive adhesive compositions based on acrylate block copolymers

摘要

Surprisingly and unforeseeably a reversibly bonded pressure sensitive adhesive can be obtained which is able automatically without technical modification to form tacky and non-tacky segments and through self-organization, using solvent coating or coating from the melt. The pressure sensitive adhesive (PSA) is based on at least one block copolymer, the wt. fractions of which account for at least 50% of the PSA, at least one copolymer being at least partly based on (meth)acrylate derivatives, and at least one block copolymer containing at least the unit P(A)-P(B)-P(A), consisting of at least one polymer block P(B) and at least two polymer blocks P(A), where: (1) P(A) independently represent homopolymer and/or copolymer blocks of monomer A, the polymer blocks p(A) each having a softening temperature range of 20-175 degrees C; (2) P(B) represents a homopolymer or copolymer block of monomers B, the polymer block P(B) having a softening temperature range of -130 - 10 degrees C; (3) the polymer blocks P(A) and P(B) are not homogeneously miscible; and (4) the (co)polymers P asterisk(A) and P asterisk(B) corresponding to the polymer blocks P(A) and P(B) each have a surface tension of at most 45 mJ/m2. An Independent claim is included for a reversible system in which the PSA is a polymer blend of one or more block copolymers, with at least one diblock copolymer P(A)-P(B), Where: the P(A) polymer blocks = homopolymer and/or copolymer blocks of monomers A, the polymer blocks P(A), P(B), and P asterisk(A) and P asterisk(B) have the above softening temperature ranges and surface tension values, and/or containing polymers P'(A) and P'(B) where polymers P', (A) = homopolymers and/or copolymers of the monomers A, the polymers P'(A) each having a softening temperature of 20-175 degrees C, the polymers P'(B) = homopolymers and/or copolymers of monomer, the polymers P'(B) each having a softening temperature of -130-10 degrees C, where the polymers P'(A) and/or P'(B) are preferably miscible with the polymer blocks P(A) and/or P(B) respectively, and the polymers P'(A) and P'(B) each have surface tension values of at most 45 mJ/m2.