Pressure-sensitive adhesives and process for preparing them

Abstract

The invention relates to a process for preparing a pressure-sensitive adhesive based on at least one polymer, in the course of which said at least one polymer is crosslinked, the polymer having functional groups Y and having been admixed, further, with at least one kind of functionalized particles which have at least one nonpolymeric base unit, wherein the particles having a surface modification of the base unit, the surface modification of the particles having at least one kind of functional groups X, and the crosslinking of the polymer being brought about at least in part by a reaction of the functional groups X of the particles and the functional groups Y of the polymer, and further to pressure-sensitive adhesives based on at least one crosslinked polymer component, the crosslinking of the polymer component being brought about at least in part by incorporation of the functionalized particles, the particles having at least one nonpolymeric base unit and also a surface modification of this base unit, and the surface modification of the particles having at least one kind of functional groups X which are capable of reacting with functional groups Y present in the polymer component, and also to the use of surface-modified functionalized particles having a nonpolymeric base unit as crosslinking reagents for crosslinking polymers for preparing pressure-sensitive adhesives.

1 . A process for preparing a pressure-sensitive adhesive comprised of at least one polymer, in the course of which said at least one polymer is crosslinked, the polymer having functional groups Y and having been admixed, further, with at least one kind of functionalized particles which have at least one nonpolymeric base unit, wherein 
 the particles have a surface modification of the base unit, the surface modification of the particles having at least one kind of functional groups X, and the crosslinking of the polymer being brought about at least in part by a reaction of the functional groups X of the particles and the functional groups Y of the polymer.    
   
   
       2 . The process as claimed in  claim 1 , wherein the at least one base unit of the at least one functionalized kind of particle is an inorganic amorphous or crystalline oxide.  
   
   
       3 . The process as claimed in  claim 1 , wherein the at least one base unit of the at least one functionalized kind of particle is an alkaline earth metal salt.  
   
   
       4 . The process as claimed in  claim 1 , wherein the at least one base unit of the at least one functionalized kind of particle is a silicate-based mineral.  
   
   
       5 . The process as claimed in  claim 1 , wherein the functional groups Y of the at least one polymer and/or the functional groups X of the at least one kind of particle have an at least partly photoinitiating character.  
   
   
       6 . The process as claimed in  claim 1 , wherein the surface modification of the at least one functionalized kind of particle is brought about by means of organosilanes, surfactants, organotitanium compounds, fatty acids and/or polyelectrolytes.  
   
   
       7 . The process as claimed in  claim 1 , wherein the reaction for bringing about the crosslinking of the pressure-sensitive adhesive is a coupling reaction, particularly one involving the formation of 
 covalent bonds    hydrogen bonds and/or    coordinative bonds.    
   
   
       8 . The process as claimed in  claim 1 , wherein the crosslinking reaction is initiated substantially by radiation.  
   
   
       9 . The process as claimed in  claim 1 , wherein the at least one functionalized kind of particle is present in the form of singular spherical particles, singular platelet-shaped particles and/or singular rodlet-shaped particles.  
   
   
       10 . The process as claimed in  claim 1 , wherein the at least one functionalized kind of particle is present in the form of particle aggregates formed from a plurality of primary particles.  
   
   
       11 . The process as claimed in  claim 9 , wherein the particles have a spatial extent of not more than 1000 nm.  
   
   
       12 . The process as claimed in  claim 1 , wherein the weight fraction of functionalized particles in the pressure-sensitive adhesive is up to 50%.  
   
   
       13 . A pressure-sensitive adhesive comprising at least one crosslinked polymer component, the crosslinking of the polymer component being brought about at least in part by incorporation of functionalized particles, the particles having at least one nonpolymeric base unit and also a surface modification of this base unit, and the surface modification of the particles having at least one kind of functional groups X which are capable of reacting with functional groups Y present in the polymer component.  
   
   
       14 . (canceled)  
   
   
       15 . A cross-linking reagent comprising surface-modified functionalized particles having a nonpolymeric base unit.  
   
   
       16 . A self-adhesive product comprising the pressure-sensitive adhesive of  claim 13 .  
   
   
       17 . The process of  claim 2 , wherein said particle is a metal oxide or a semimetal oxide.  
   
   
       18 . The process of  claim 4 , wherein said silicate-based mineral is a clay mineral.  
   
   
       19 . The process of  claim 8 , wherein said radiation is UV radiation.  
   
   
       20 . The process as claimed in  claim 10 , wherein the particle aggregates have a spatial extent of not more than 1000 nm.  
   
   
       21 . The process as claimed in  claim 20 , wherein the particle aggregates have a spatial extent in at least one spatial direction of not more than 250 nm.  
   
   
       22 . The process as claimed in  claim 21 , wherein the particle aggregates have a spatial extent in at least one spatial direction of not more than 100 nm.  
   
   
       23 . The process as claimed in  claim 11 , wherein the particles have a spatial extent in at least one spatial direction of not more than 250 nm.  
   
   
       24 . The process as claimed in  claim 23 , wherein the particles have a spatial extent in at least one spatial direction of not more than 100 nm.  
   
   
       25 . The process of  claim 12 , wherein said weight fraction of functionalized particles is up to 20%.  
   
   
       26 . The process of  claim 21 , wherein said weight fraction of functionalized particles is up to 12%.