Hydrogenated elastomer primed polyolefin film

Abstract

A pressure-sensitive tape is provided having a polyolefin backing, a primer comprising an elastomeric block copolymer which primer is applied from a non-aromatic hydrocarbon solvent, said tape further comprising an adhesive on the thus primed surface. Because the primer is laid down from a solution in a non-aromatic hydrocarbon solvent such as methyl cyclohexane the process utilizes an environmentally-friendly solvent.

What is claimed is:  
     
       1. A process comprising: 
       applying a solution consisting of a selectively hydrogenated elastomeric block copolymer having at least two resinous end-blocks of polymerized monovinylaromatic compound and an elastomeric mid-block of a polymerized conjugated diene and a non-aromatic hydrocarbom solvent to a surface of a polyolefin film; and  
       evaporating said solvent to deposit the selectively hydrogenated elastomeric block copolymer as a primer coating on said surface, said primer coating effective as a tie-coat between said polyolefin film and an adhesive.  
     
     
       2. The process according to claim  1  wherein said hydrogenated elastomeric block copolymer is derived from a copolymer selected from the group consisting of linear styrene-butadiene-styrene and linear styrene-isoprene-styrene. 
     
     
       3. The process according to claim  2  wherein said end-blocks have a peak molecular weight within the range of 5,000 to 15,000 and wherein said block copolymer contains 13 to 40 weight percent of said styrene and has a total peak molecular weight within the range of 60,000 to 180,000. 
     
     
       4. The process according to claim  1  wherein said block copolymer has 0.02-5 weight percent, based on the weight of said block copolymer, of a grafted material. 
     
     
       5. The process according to claim  1  wherein said block copolymer has 0.2-2 weight percent, based on the weight of said block copolymer, of grafted maleic anhydride. 
     
     
       6. The process according to claim  1  wherein said film is biaxially oriented polypropylene. 
     
     
       7. The process according to claim  1  said surface of said film has no surface treatment. 
     
     
       8. The process according to claim  1  wherein said non-aromatic hydrocarbon solvent is methyl cyclohexane. 
     
     
       9. The process according to claim  1  wherein said solution has 5-10 weight percent concentration of said copolymer. 
     
     
       10. The process according to claim  9  wherein said hydrogenated elastomeric block copolymer is derived from a linear styrene-butadiene-styrene copolymer wherein said end-blocks have a peak molecular weight within the range of 5,000 to 15,000 and wherein said block copolymer contains 13 to 40 weight percent of said styrene and has a total peak molecular weight of 60,00 to 180,000, and wherein said block copolymer contains 0.2-2 weight percent of grafted maleic anhydride, wherein said film is biaxially oriented polypropylene having no surface treatment and wherein said solvent comprises predominantly methyl cyclohexane.