Residuelessly redetachable contact-adhesive sheetlike structures

Abstract

Residuelessly redetachable contact-adhesive sheet-like structures wherein are provided approximately calotte-shaped bonding sites which are up to about 600 μm in diameter at the base where the calottes stick to the sheet-like structure and which are produced by screen or gravure printing using high-solids dispersion of adhesive substance.

What is claimed is:  
     
       1. A residuelessly redetachable contact-adhesive sheetlike structure wherein are provided approximately calotte-shaped bonding sites which are up to about 600 μm in diameter at the base where the calottes stick, to a surface of the sheetlike structure and wherein the sites are completely isolated from each other on the surface and which  are produced by screen or gravure printing using high-solids dispersions of adhesive substances. 
     
     
       2. A contact-adhesive sheetlike structure as claimed in  claim 1  wherein the adhesive used has high surface tension, adhesivity, film-forming properties and elastomeric properties. 
     
     
       3. A contact-adhesive sheetlike structure as claimed in claims  1  and  2   wherein the adhesive used is based on (meth)acrylic acid esters with or without small proportions of other monomer units. 
     
     
       4. A contact-adhesive sheetlike structure as claimed in any one of claims  1 - 3   claim 1 wherein the dispersions used are aqueous dispersions, or organosols or plastisols. 
     
     
       5. A contact-adhesive sheetlike structure as claimed in  claim 4  wherein the aqueous dispersions used are concentrated thixotropic contact-adhesive dispersions having a solids content of 55-65% by weight. 
     
     
       6. A contact-adhesive sheetlike structure as claimed in any one of claims  1 - 5   claim 1 wherein the base diameter of the calotte-shaped bonding sites is  80-500, in particular  100-400  μm. 
     
     
       7. A contact-adhesive sheetlike structure as claimed in any one of claims  1 - 6   claim 1 - 6 wherein the bonding sites are subsequently crosslinked. 
     
     
       8. A contact-adhesive sheetlike structure as claimed in  claim 7  wherein the bonding sites are subsequently cross linked by electron beam. 
     
     
       9. A contact-adhesive sheetlike structure as claimed in any one of claims  1 - 8   claim 1 which has the most suitable geometric arrangement and number (per unit area) of bonding sites for the proposed adhesive attachment. 
     
     
       10. A residuelessly redetachable adhesive article comprising a substrate bearing a plurality of mechanically applied approximately calotte-shaped adhesive sites, each site having a base in direct contact with a surface of the substrate and which is up to  600  μm in cross-base dimension and wherein the sites are completely isolated form each other on the surface of the substrate. 
     
     
       11. The article according to  claim 10 , wherein each base is from  80  to  500  μm in cross-base dimension. 
     
     
       12. The article according to  claim 11 , wherein each base is from  100  to  400  μm in cross- base dimension.   
     
     
       13. The article according to  claim 10 , wherein the height of each site is from about  30  to  600  μm. 
     
     
       14. The article according to  claim 10 , wherein each base is from about  30  to  600  μm in cross- base dimension.   
     
     
       15. A method of making a residuelessly redetachable adhesive article, comprising the steps of providing a substrate and mechanically applying a plurality of approximately calotte- shaped adhesive sites on a surface of the substrate each site having a base up to  600  μm in cross - base dimension and wherein the sites are completely isolated from each other on the surface of the substrate.   
     
     
       16. The method according to  claim 15 , wherein the step of mechanically applying comprises applying a high- solids dispersion of contact adhesives and drying.   
     
     
       17. The method according to  claim 16 , wherein the step of mechanically applying comprises gravure printing. 
     
     
       18. The method according to  claim 16 , wherein the step of mechanically applying comprises screen printing. 
     
     
       19. The method according to  claim 15 , wherein the step of mechanically applying a high solids dispersion comprises applying concentrated thixotropic contact- adhesive aqueous dispersions having a solids content of  55  to  65 % by weight.   
     
     
       20. The method according to  claim 15 , wherein each site is applied with a base from about  30  to  600  μm in cross- base dimension.