PRESSURE-SENSITIVE ADHESIVE COMPRISING A CROSSLINKABLE POLYOLEFIN AND A TACKIFIER RESIN
Pressure-sensitive adhesive comprising a crosslinkable polyolefin and at least one tackifier resin, wherein the polyolefin is composed of at least two monomers A and B and of at least one comonomer C amenable to crosslinking, the monomers A and B being selected from the group consisting of α-olefins, vinyl acetate, n-butyl acrylate and methyl methacrylate or, in the case of EPDM, a diene such as 5-ethylidene-2-norbornene, dicyclopentadiene or 5-vinyl-2-norbornene.
1 . A pressure-sensitive adhesive comprising a crosslinkable polyolefin and at least one tackifier resin, wherein the polyolefin is composed of at least two monomers, A and B, and of at least one comonomer C amenable to crosslinking, the monomers A and B being selected from the group consisting of α-olefins, vinyl acetate, n-butyl acrylate and methyl methacrylate, and ethylene propylene diene monomer (EPDM).
2 . The pressure-sensitive adhesive according to claim 1 , wherein the at least two monomers A and B of the crosslinkable polyolefin are α-olefins.
3 . The pressure-sensitive adhesive according to claim wherein the polyolefin has a melt index of less than 10.
4 . The pressure-sensitive adhesive according to claim 1 wherein the polyolefin is a terpolymer of ethylene, of an ester of acrylic or methacrylic acid and of a comonomer which is amenable to crosslinking, or is a copolymer grafted with the comonomer, selected from the group of the copolymers of ethylene and propylene, the copolymers of propylene and butene, the copolymers of hexene or octene, the copolymers of propylene and butene, and the terpolymers of ethylene, propylene and a diene from the group of 5-ethylidene-2-norbornene, dicyclopentadiene and 5-vinyl-2-norbornene.
5 . The pressure-sensitive adhesive according to claim 1 wherein the polyolefin is obtainable by copolymerization of the at least two monomers A and B with the comonomer C.
6 . The pressure-sensitive adhesive according to claim 1 wherein the polyolefin is obtainable by polymerization of the at least two monomers A and B in order to form a polymer, and grafting of the comonomer C onto the polymer.
7 . The pressure-sensitive adhesive according to claim 1 wherein the pressure-sensitive adhesive comprises a plasticizer selected from the group of mineral oils, liquid tackifier resins, liquid polymers of isobutene homopolymer and/or isobutene-butene copolymer, and esters of phthalic, trimellitic, citric or adipic acid.
8 . A process for preparing a pressure-sensitive adhesive tape comprising applying the pressure-sensitive adhesive according to claim 1 from a toluene solution to a carrier and crosslinking the adhesive with a crosslinker selected from the group consisting of an isocyanate, an epoxide, a titanium compound, an aluminium compound, an oxazoline, an aziridine and an amine.
9 . A process for preparing a pressure-sensitive adhesive tape comprising applying the pressure-sensitive adhesive according to claim 1 from a melt to a carrier, and crosslinking the adhesive with a crosslinker selected from the group consisting of an epoxide, an amine, a zinc compound and a magnesium compound.
10 . A single-sided or double-sided adhesive tape comprising an adhesive according to claim 1 , the adhesive tape having at least on one side a bond strength to steel of at least 0.5 N/cm.
11 . The single-sided or double-sided adhesive tape according to claim 10 wherein the coatweight of the pressure-sensitive adhesive in one coat being between 15 and 300 g/m 2 .
12 . The single-sided or double-sided adhesive tape according to claim 10 wherein the shear strength is at least 200 min and/or the elastic component from the microshear travel test is at least 15%.
13 . The single-sided or double-sided adhesive tape according to claim 10 , wherein the tape comprises a polyethylene foam carrier whose surfaces in contact with the adhesive have not been (pre)treated.
14 . The single-sided or double-sided adhesive tape according to claim 13 wherein the carrier is a nonwoven, a tissue, a film or a foam.
15 . (canceled)
16 . The pressure-sensitive adhesive according to claim 1 wherein the EPDM is selected from the group consisting of 5-ethylidene-2-norbornene, dicyclopentadiene and 5-vinyl-2-norbornene.
17 . The pressure-sensitive adhesive according to claim 2 wherein the α-olefin is selected from the group consisting of ethylene, propylene, butene, hexene and octane.
18 . The pressure-sensitive adhesive according to claim 1 wherein the polyolefin has a Mooney viscosity greater than 5.
19 . The pressure-sensitive adhesive according to claim 5 wherein the comonomer C is selected from the group consisting of fumaric acid, acrylic acid, methacrylic acid or itaconic acid.
20 . The single-sided or double-sided adhesive tape according to claim 10 wherein the adhesive tape has at least on one side a bond strength to steel of at least 9 N/cm.