Self-levelling under-packing for printing presses

Abstract

The self-levelling under-packing for printing presses, in particular offset presses, comprises at least one polyester-based layer and at least one polyurethane elastomer layer joined inseparably together.

1 . Self-levelling under-packing for printing presses, comprising at least one polyester-based layer and at least one polyurethane elastomer layer joined inseparably together.  
     
     
         2 . Under-packing as claimed in  claim 1 , wherein the polyester-based layer is between 50 μm and 350 μm and the polyurethane elastomer layer is between 20 μm and 1000 μm.  
     
     
         3 . Under-packing as claimed in  claim 1 , wherein the polyester-based layer is adhesive-coated on one side, in which case the thickness, including the adhesive, is between 40 and 100 μm, the adhesive thickness not exceeding about 5 μm.  
     
     
         4 . Under-packing as claimed in  claim 1 , wherein several polyester-based layers and several polyurethane elastomer layers are provided, at least some of the layers of the one alternating with layers of the other.  
     
     
         5 . Under-packing as claimed in  claim 1 , wherein the elastomeric component presents the following chemical/physical characteristics:  
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Shore hardness A 
                   75-95 
                   DIN 53505 
                 
                     
                   Density g/cm 3   
                   1.10-1.25 
                   DIN 53479 
                 
                     
                   Cyclic compression % 
                   60% compressible 
                   DIN 53517 
                 
                     
                   Resilience % 
                   30-40 
                   DIN 53512 
                 
                     
                   Solvent resistance 
                   resistant 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         (wherein the cyclic compression test is performed by carrying out a cycle of one million compressions (of 60% on the compressible side, i.e. on the polyurethane elastomer side) without undergoing any thickness decrease).  
       
     
     
         6 . Under-packing as claimed in  claim 5 , wherein the same chemical-physical characteristics apply to the polyurethane elastomer.  
     
     
         7 . Under-packing as claimed in  claim 1 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         8 . Under-packing as claimed in  claim 5 , wherein a plurality of the polyurethane elastomer layers are used, at least one of these layers having different said chemical;/physical characteristics from the remaining layers.  
     
     
         9 . Under-packing as claimed in  claim 1 , wherein the removable polyester layers are not more than three in number, with none of them exceeding 50 μm thickness.  
     
     
         10 . Under-packing as claimed in  claim 2 , wherein several polyester-based layers and several polyurethane elastomer layers are provided, at least some of the layers of the one alternating with layers of the other.  
     
     
         11 . Under-packing as claimed in  claim 2 , wherein the elastomeric component presents the following chemical/physical characteristics:  
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Shore hardness A 
                   75-95 
                   DIN 53505 
                 
                     
                   Density g/cm 3   
                   1.10-1.25 
                   DIN 53479 
                 
                     
                   Cyclic compression % 
                   60% compressible 
                   DIN 53517 
                 
                     
                   Resilience % 
                   30-40 
                   DIN 53512 
                 
                     
                   Solvent resistance 
                   resistant 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         (wherein the cyclic compression test is performed by carrying out a cycle of one million compressions (of 60% on the compressible side, i.e. on the polyurethane elastomer side) without undergoing any thickness decrease).  
       
     
     
         12 . Under-packing as claimed in  claim 3 , wherein the elastomeric component presents the following chemical/physical characteristics:  
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Shore hardness A 
                   75-95 
                   DIN 53505 
                 
                     
                   Density g/cm 3   
                   1.10-1.25 
                   DIN 53479 
                 
                     
                   Cyclic compression % 
                   60% compressible 
                   DIN 53517 
                 
                     
                   Resilience % 
                   30-40 
                   DIN 53512 
                 
                     
                   Solvent resistance 
                   resistant 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         (wherein the cyclic compression test is performed by carrying out a cycle of one million compressions (of 60% on the compressible side, i.e. on the polyurethane elastomer side) without undergoing any thickness decrease).  
       
     
     
         13 . Under-packing as claimed in  claim 4 , wherein the elastomeric component presents the following chemical/physical characteristics:  
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Shore hardness A 
                   75-95 
                   DIN 53505 
                 
                     
                   Density g/cm 3   
                   1.10-1.25 
                   DIN 53479 
                 
                     
                   Cyclic compression % 
                   60% compressible 
                   DIN 53517 
                 
                     
                   Resilience % 
                   30-40 
                   DIN 53512 
                 
                     
                   Solvent resistance 
                   resistant 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
               
            
           
         
         (wherein the cyclic compression test is performed by carrying out a cycle of one million compressions (of 60% on the compressible side, i.e. on the polyurethane elastomer side) without undergoing any thickness decrease).  
       
     
     
         14 . Under-packing as claimed in  claim 2 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         15 . Under-packing as claimed in  claim 3 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         16 . Under-packing as claimed in  claim 4 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         17 . Under-packing as claimed in  claim 5 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         18 . Under-packing as claimed in  claim 6 , wherein a plurality of the superposed polyester layers of the superposed polyester layers being used, some are removably joined together by a pressure sensitive adhesive strip along one of their edges.  
     
     
         19 . Under-packing as claimed in  claim 2 , wherein the removable polyester layers are not more than three in number, with none of them exceeding 50 μm thickness.  
     
     
         20 . Under-packing as claimed in  claim 3 , wherein the removable polyester layers are not more than three in number, with none of them exceeding 50 μm thickness.