Pressure-sensitive adhesive compound containing a cross-linked nanoparticle network, method of production and use thereof

Abstract

Pressure-sensitive adhesive compound comprising at least two components forming one phase each, from which an IPN with at least two phases is produced by a cross-linking build-up reaction, the first phase having at least a softening point temperature of less than 23° C., and the second phase, after the build up reaction, having a softening temperature of greater than 23° C., the two phases having a morphology of a cross-linked nanoparticle network after the build-up reaction.

1 . A pressure-sensitive adhesive comprising
 at least two constituents, each forming a phase, from which an IPN having at least two phases is formed by a crosslinking buildup reaction,   the first phase (elastomer phase) having at least a DSC softening temperature of less than 23° C. and the second phase after the buildup reaction having a DSC softening temperature of greater than 23° C.,   the second phase after the buildup reaction having the morphology of a connected nanoparticle network.   
     
     
         2 . The pressure-sensitive adhesive as claimed in  claim 1 ,
 wherein   the IPN is a semi-IPN wherein the first phase, the elastomer phase, is in a form in which it is not crosslinked.   
     
     
         3 . The pressure-sensitive adhesive as claimed in  claim 1 ,
 wherein   the elastomer phase is crosslinked physically such as by domain formation in the case of block copolymers and/or coordinatively such as by coordination of acid groups to metal chelates.   
     
     
         4 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein
 the IPN is formed sequentially, and so the elastomer phase is crosslinked before the second phase.   
     
     
         5 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein elastomers used are acrylates and/or methacrylates, polyurethanes, natural rubbers, synthetic rubbers such as randomly copolymerized styrene-butadiene rubbers (SBR), butadiene rubbers (BR), synthetic polyisoprenes (IR), butyl rubbers (IIR), halogenated butyl rubbers (XIIR), acrylate rubbers (ACM), ethylene-vinyl acetate copolymers (EVA) or polyurethanes and/or blends thereof, styrene block copolymers having an elastomer block of unsaturated or partly or fully hydrogenated polydiene blocks (polybutadiene, polyisoprene, poly(iso)butylene, copolymers thereof), polyolefins, fluoropolymers and/or silicones. 
     
     
         6 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein
 the elastomers used are vinylaromatic block copolymers.   
     
     
         7 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein reactive components used for the second phase are epoxides, polyesters, polyethers, polyurethanes, phenolic resin polymers, cresol based, or novolak based polymers, polysulfides, or acrylic polymers. 
     
     
         8 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein the buildup reaction takes place cationically or by means of a controlled radical mechanism selected from the group consisting of RAFT, ATRP, and NMRP. 
     
     
         9 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein the mass ratio of elastomer phase to hard phase is between 85:15 50:50. 
     
     
         10 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein the pressure-sensitive adhesive comprises at least one kind of a an at least partly hydrogenated tackifier resin, compatible with the elastomer component and/or, where a copolymer composed of hard blocks and soft blocks is used. 
     
     
         11 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein
 the pressure-sensitive adhesive is transparent in the visible light range of the spectrum.   
     
     
         12 . The pressure-sensitive adhesive as claimed in  claim 1 , wherein the pressure-sensitive adhesive exhibits a haze of less than 5.0%. 
     
     
         13 . An adhesive tape comprising a layer of a pressure-sensitive adhesive of  claim 1  or consisting of a layer of a pressure-sensitive adhesive of  claim 1 . 
     
     
         14 . An adhesive tape comprising
 a layer of a pressure-sensitive adhesive of  claim 1  applied to a carrier on at least one side, or a layer of a pressure-sensitive adhesive of  claim 1  applied to a carrier on both sides.   
     
     
         15 . The adhesive tape as claimed in  claim 13 , wherein the thickness of the pressure-sensitive adhesive is between 1 μm and 2000 μm. 
     
     
         16 . A method for encapsulating an (opto)electronic arrangement which comprises encapsulating such (opto)electronic arrangement with a pressure-sensitive adhesive or a single-sidedly or double-sidedly adhesive tape formed with the pressure-sensitive adhesive of  claim 1 . 
     
     
         17 . A method for forming a structural adhesive bond which comprises forming said structural adhesive bond with a pressure-sensitive adhesive or of a single-sidedly or double-sidedly adhesive tape formed with the pressure-sensitive adhesive, as claimed in  claim 1 . 
     
     
         18 . A method for producing the pressure-sensitive adhesive of  claim 1 , which comprises the following steps:
 1) producing a homogeneous mixture of at least one elastomer, at least one reactive component, and optionally a tackifier resin, in which the mass fraction of the reactive component is less than or equal to the sum of the elastomer and of the optional tackifier resin   2) initiating the buildup reaction of the reactive component, disperse nanoparticles being built up from the reactive component and connecting to one another to form a network of nanoparticles within the elastomer phase.   
     
     
         19 . The method for producing a pressure-sensitive adhesive as claimed in  claim 18 , wherein
 the buildup reaction is a crosslinking reaction, a chain-growth addition polymerization, or a one-, two-, or three-dimensional chain growth reaction.