Method of making composite packing material for use in offset lithography

Abstract

A composite packing material for use with a printing blanket is provided including a substrate such as fabric, scrim, or film which is coated on at least one surface with a polymeric compound to provide the desired gauge to the printing blanket assembly. The resulting composite packing material has a thickness of about 0.010 to about 0.067 inches (0.25 mm to 1.7 mm) and is substantially volume non-compressible.

1 . A method of making a composite packing material for use with a printing blanket comprising:
 providing a substrate having first and second surfaces which is selected from the group consisting of fabric, scrim and film;   applying to at least one of said first and second surfaces of said substrate a polymeric compound selected from polyvinyl chloride, urethanes, compounded synthetic rubbers, and blends thereof.   
   
   
       2 . The method of  claim 1  wherein said substrate comprises a fabric selected from weft insertion fabric, woven fabric, and non-woven fabric. 
   
   
       3 . The method of  claim 1  wherein said substrate comprises a weft insertion fabric comprising yarns of at least 1000 denier. 
   
   
       4 . The method of  claim 1  wherein said polymeric compound comprises polyvinyl chloride. 
   
   
       5 . The method of  claim 4  wherein said polyvinyl chloride has a Shore A hardness of from about 60 to about 80. 
   
   
       6 . The composite packing material of  claim 1  wherein said polymeric compound has a compression set of less than about 25. 
   
   
       7 . The composite packing material of  claim 1  wherein said polymeric compound has a compression set of less than about 10. 
   
   
       8 . The composite packing material of  claim 1  wherein said polymeric compound has a compression set of less than about 4. 
   
   
       9 . The method of  claim 1  including buffing the surface of said substrate containing said polymeric compound thereon. 
   
   
       10 . The method of  claim 1  wherein said polymeric compound is applied by coating. 
   
   
       11 . The method of  claim 1  wherein said polymeric compound is applied by laminating. 
   
   
       12 . The method of  claim 1  wherein said polymeric compound is applied to said first and second surfaces of said substrate. 
   
   
       13 . The method of  claim 1  wherein said composite packing material has a thickness of at about 0.010 inches to about 0.067 inches (0.25 mm to 1.7 mm). 
   
   
       14 . The method of  claim 1  wherein said composite packing material is substantially non-compressible.