Patent ID: 6183814
Filing Date: 2001-02-06
Classification: C08G,C09D,D21H,Y10T

Abstract:
A method for coating paper, the method comprising steps of:(a) melting a polylactide polymer composition in an extruder to provide a melted polylactide polymer composition at a temperature of between about 495.degree. F. and about 540.degree. F.; said polylactide polymer composition comprising:(i) peroxide modified polylactide polymer having an optical purity of S-lactic acid repeating units of greater than about 90% and resulting from compounding polylactide polymer and peroxide at a weight percent of peroxide of between about 0.005 wt. % and about 5 wt. %;(ii) residual lactide level of less than about 1 wt. %;(iii) the polylactide polymer has a weight average molecular weight of between about 80,000 and about 300,000;(iv) the polylactide polymer has a ratio of Mz to Mn of greater than about 6; and(v) the polylactide polymer has a polydispersity index of greater than about 2.5;(b) extrusion coating the melted polylactide polymer composition from the extruder and onto a paper layer at a line speed of between about 500 ft/min and about 2000 ft/min to provide a coated paper product comprising a paper layer and a polymer layer, the polymer layer comprising the extrusion coated polylactide polymer composition; and(c) pressing the coated paper product between a nip roller and a chill roller to enhance adhesion between the paper layer and the polymer layer, wherein the chill roller contacts the polylactide polymer composition and has a surface temperature of less than about 130.degree. F.