Graphic articles comprising polylactic acid polymer based film

Abstract

A method of forming a graphic article is described such as a tape or sheet, comprising a PLA-based film. The PLA-based film comprises a semicrystalline polylactic acid polymer; a second polymer such as polyvinyl acetate polymer having a glass transition temperature (Tg) of at least 25° C.; and plasticizer. The graphic article is typically a tape or sheet that may further comprise a (e.g. pressure sensitive) adhesive and a low adhesion backsize or a release liner. The graphic article can be suitable for various end-uses.

What is claimed: 
     
         1 . A method of forming a graphic article comprising
 providing a first film layer comprising semicrystalline polylactic acid polymer, polyvinyl acetate polymer, and plasticizer; wherein the film comprises
 10 to 50 wt. % of polyvinyl acetate polymer having a Tg of at least 25° C., based on the total amount of polylactic acid polymer(s), polyvinyl acetate polymer and plasticizer; and 
 5 to 35 wt. % plasticizer, based on the total amount of polylactic acid polymer(s), polyvinyl acetate polymer and plasticizer; and 
   printing a graphic on the first film layer.   
     
     
         2 . The method of  claim 1  wherein the graphic comprises a dried and/or cured ink layer. 
     
     
         3 . The method of  claim 2  wherein the ink layer comprises a colorant. 
     
     
         4 . The method of  claim 2  wherein the ink layer comprises a polymeric binder. 
     
     
         5 . The method of  claim 2  wherein the ink layer is a dried and/or cured radiation cured ink, organic solvent-based ink, or water-based ink. 
     
     
         6 . The method of  claim 2  wherein the dried and/or cured ink is an ink jetted ink or a screen printed ink. 
     
     
         7 . The method of  claim 1  further comprises a topcoat layer disposed on the graphic. 
     
     
         8 . The method of  claim 1  further comprising a cover film disposed on the graphic. 
     
     
         9 . The method of  claim 8  wherein the cover film is bonded to the graphic with an adhesive layer. 
     
     
         10 . The method of  claim 8  wherein the cover film comprises a semicrystalline polylactic acid polymer. 
     
     
         11 . The method of  claim 1  wherein the first film layer further comprises an amorphous polylactic acid polymer. 
     
     
         12 . The method of  claim 1  wherein the polyvinyl acetate polymer has a molecular weight ranging from 75,000 g/mol to 750,000 g/mol. 
     
     
         13 . The method of  claim 1  wherein the polyvinyl acetate polymer has a glass transition temperature no greater than 50 or 45° C. 
     
     
         14 . The method of  claim 1  further comprising a nucleating agent in an amount ranging from about 0.01 wt. % to about 1 wt. %. 
     
     
         15 . The method of  claim 1  where the first film layer has a tensile elongation from 50% to 600% and does not exhibit plasticizer migration when aged at 80° C. for 24 hours. 
     
     
         16 . The method of  claim 15  wherein the first film layer has a tensile strength ranging from 10 to 40 MPa. 
     
     
         17 . The method of  claim 1  further comprising apply a pressure sensitive adhesive to the opposing surface of the first film layer. 
     
     
         18 . The method of  claim 17  wherein the pressure sensitive adhesive further comprises a removable release liner.