Blend of at least two components K1 and K2, each component being based on at least one block copolymer C1 or C2 respectively, • the at least one block copolymer C1 of component K1 comprising at least the unit P -P -P, comprising at least one polymer block P and at least two polymer blocks P, where - P independently at each occurrence represents homopolymer or copolymer blocks of monomers A1, the polymer blocks P each having a softening temperature in the range from +20°C to +175°C, - P represents a homopolymer or copolymer block of monomers B1, the polymer block P having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, • the at least one block copolymer C2 of component K2 comprising at least the unit P -P -P, comprising at least two polymer blocks P and at least one polymer block P, where - P represents a homopolymer or copolymer block of monomers A2, the polymer block P having a softening temperature in the range from +20°C to +175°C, - P independently at each occurrence represents homopolymer or copolymer blocks of monomers B2, the polymer blocks P each having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, • the monomers of polymer blocks P and P being selected in each case to an extent of 75 to 100% by weight from the group of acrylic and/or methacrylic acid derivatives of the general structure CH 2 =C(R 1) (COOR 2), where R 1 = H or CH 3 and R 2 = H or linear, branched or cyclic, saturated or unsaturated hydrocarbon radicals having 1 to 30 carbon atoms, • and the blend forming an at least two-phase system. • the at least one block copolymer C1 of component K1 comprising at least the unit P -P -P, comprising at least one polymer block P and at least two polymer blocks P, where - P independently at each occurrence represents homopolymer or copolymer blocks of monomers A1, the polymer blocks P each having a softening temperature in the range from +20°C to +175°C, - P represents a homopolymer or copolymer block of monomers B1, the polymer block P having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, - P independently at each occurrence represents homopolymer or copolymer blocks of monomers A1, the polymer blocks P each having a softening temperature in the range from +20°C to +175°C, - P represents a homopolymer or copolymer block of monomers B1, the polymer block P having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, • the at least one block copolymer C2 of component K2 comprising at least the unit P -P -P, comprising at least two polymer blocks P and at least one polymer block P, where - P represents a homopolymer or copolymer block of monomers A2, the polymer block P having a softening temperature in the range from +20°C to +175°C, - P independently at each occurrence represents homopolymer or copolymer blocks of monomers B2, the polymer blocks P each having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, - P represents a homopolymer or copolymer block of monomers A2, the polymer block P having a softening temperature in the range from +20°C to +175°C, - P independently at each occurrence represents homopolymer or copolymer blocks of monomers B2, the polymer blocks P each having a softening temperature in the range from -130°C to +10°C, - the polymer blocks P and P are not homogeneously miscible with one another, • the monomers of polymer blocks P and P being selected in each case to an extent of 75 to 100% by weight from the group of acrylic and/or methacrylic acid derivatives of the general structure CH 2 =C(R 1) (COOR 2), where R 1 = H or CH 3 and R 2 = H or linear, branched or cyclic, saturated or unsaturated hydrocarbon radicals having 1 to 30 carbon atoms, • and the blend forming an at least two-phase system.