▎ 摘　　要

NOVELTY - High stretch ratio film comprises outer layer, intermediate layer and inner layer, where the outer layer is 300-500 pts. wt. metallocene linear low density polyethylene or 500-700 pts. wt. ethylene-modified polyethylene terephthalate, the intermediate layer is 100-300 pts. wt. maleic anhydride grafted low density polyethylene or 40-80 pts. wt. graphene oxide modified low density polyethylene, the inner layer is 100-200 pts. wt. polyamide-11 or polyamide-12 and the preparation of graphene oxide modified low density polyethylene comprises mixing graphene oxide with deionized water, dispersing uniformly by ultrasonic stirring to obtain graphene oxide solution, adding low density polyethylene to graphene oxide solution, uniformly stirring, vacuum filtering and carrying out crosslinking reaction using ultraviolet light irradiation, the mass ratio of graphene oxide to deionized water is 0.8-1.2:1 and the mass ratio of low density polyethylene to graphene oxide solution is 1:2-5. USE - Used as high stretch ratio film. ADVANTAGE - The film has high stretching ratio, good comprehensive performance and strong market competitiveness and is economical. The method has high draw ratio. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the film, comprising (i) subjecting outer layer of film to 170-200 degrees C and melt-plasticizing intermediate layer and inner layer for 2 hours to obtain melt I, melt II and melt III, (ii) subjecting melt I, melt II and melt III to green body at extrusion speed of 0.6-1.0 m/s, respectively, fixing blank in prefabricated mold and controlling rotation speed of mold to 3-5 rad/minute to obtain parison having viscosity of 800-1000 mPas, (iii) subjecting parison to extrusion blow molding under pressure of 0.8-1.5 MPa, controlling the inflation ratio to 2-5:1 and aspect ratio of 20-40:1 and cooling operation using cooling water at flow rate of 40-60 l/minute, and (iv) drowning preliminary product using twin-screw extruder, setting tension of drawing to 120-150 kg/cm2, controlling the draft ratio to 2-3 and carry out winding and packaging operations.