Coating grade polylactide and coated paper, preparation and uses thereof, and articles prepared therefrom
AssigneeCargill, Incorporated
InventorsJames Nangeroni, Mark H. Hartmann, Matthew L. Iwen, Christopher Michael Ryan, Jeffrey J. Kolstad, Kevin T. McCarthy
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Abstract
A coated paper product including a paper layer and a polymer layer, wherein the polymer layer includes a polylactide polymer composition having a ratio of Mz to Mn of greater than about 6. The polymer composition, when melted, exhibits a die swell of greater than about 1.25 for a melt flow index of greater than about 2. Polymer lactide compositions, methods of manufacturing the polymer composition and the coated paper product, and articles produced therefrom are also described.
Claims45
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° F. and about 540° 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° F.
A method for coating paper according to claime 34, wherein the second polymer layer comprises polylactide polymer.
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° F. and about 540° 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 polylactide polymer composition flow rate of between about 5 lb/hr per inch of die width to about 25 lb/hr per inch of die width 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° F.
Dependencies are inferred from the claim text.