METHOD FOR PRODUCTION BY COEXTRUSION OF POLYETHYLENE MULTI-LAYER FILM AND MULTI-LAYER FILM PRODUCED IN SUCH A WAY Russian patent published in 2003 - IPC

FIELD: multi-layer film designed for packing of stacked modules. SUBSTANCE: the method consists in coextrusion of polyethylene multi-layer film by means of a group of extruders. The multi-layer material coming out of the expanding head is gathered on the cooling roller cooled by water at a temperature of 10 and 25C. Then, the film coming off the first cooling roller is fed to the second cooling roller cooled by water maintained at a temperature of hot below the temperature of the first roller. The peripheral velocity or rotational speed of the second roller exceeds the speed of the first roller by 10 to 40%. By controlling the cooling and extension conditions very hard and extensible films at the same time are obtained, they have the value of the yield point within 15 to 80 H/sq.mm, and critical elongation within 50 to 500%. EFFECT: improved quality. 15 cl, 2 tbl