▎ 摘　　要

NOVELTY - Method for improving barrier property of polyolefin-based materials, comprises (i) melting and blending 40-99 pts. wt. polyolefin, 1-60 pts. wt. polymer A, 0.01-20 pts. wt. compatibilizer, 0.1-10 pts. wt. functional auxiliary agent, and 0-5 pts. wt. two-dimensional fillers by screw extruder and extruding to form film or sheet, and quickly cooling to temperature 1; and (ii) bi-directionally stretching the cooled film or sheet 2-15 times at a temperature of 2 using a flat film bi-directional stretching process, and carrying out heat treatment at a temperature of 3 to obtain a polyolefin-based barrier film, where the melt blending temperature is 1-50 degrees C above the melting point of the higher melting point components in polyolefin and polymer A, the temperature 1 is 1-150 degrees C below the melting point of polyolefin, temperature 2 is 30-200 degrees C above the glass transition temperature of polyolefin, and temperature 3 is 50-230 degrees C above the glass transition temperature of polyolefin. USE - The polyolefin-based barrier film is useful in packaging fields of daily necessities, chemical industry, food, food additive and medicine (claimed). ADVANTAGE - The method deforms the dispersed phase polymer A in the polyolefin film in situ by a specific bi-directional stretching process to generate a huge two-dimensional sheet structure, which increases the diffusion path of small molecules in the film, reduces the gas permeability coefficient by 1-2 orders of magnitude, and bridges the two-dimensional filler and the two-dimensional polymer A formed in situ to form a barrier network, which has the special effect of synergistically blocking small gas molecules. The high barrier packaging material creatively obtains a special microstructure with a macro single layer, a micro multi-layer and a multi-component in situ, gives the material excellent gas barrier properties, is easy to be recycled and reused and has very good application prospects. DETAILED DESCRIPTION - Method for improving barrier property of polyolefin-based materials, comprises (i) melting and blending 40-99 pts. wt. polyolefin, 1-60 pts. wt. polymer A, 0.01-20 pts. wt. compatibilizer, 0.1-10 pts. wt. functional auxiliary agent, and 0-5 pts. wt. two-dimensional fillers by screw extruder and extruding to form film or sheet, and quickly cooling to temperature 1; and (ii) bi-directionally stretching the cooled film or sheet 2-15 times at a temperature of 2 using a flat film bi-directional stretching process, and carrying out heat treatment at a temperature of 3 to obtain a polyolefin-based barrier film, where the melt blending temperature is 1-50 degrees C above the melting point of the higher melting point components in polyolefin and polymer A, the temperature 1 is 1-150 degrees C below the melting point of polyolefin, temperature 2 is 30-200 degrees C above the glass transition temperature of polyolefin, and temperature 3 is 50-230 degrees C above the glass transition temperature of polyolefin; or (a) melting and blending 40-99 pts. wt. polyolefin, 1-60 pts. wt. polymer A, 0.01-20 pts. wt. compatibilizer, 0.1-10 pts. wt. functional auxiliary agent, 0-5 pts. wt. two-dimensional filler and extruding through a pipe die to form a pipe blank, and quickly cooling the pipe blank to temperature 1; and (b) inflating the pipe blank, stretching, and shaping using a pipe film bi-directional stretching process at a temperature of 2 to obtain a polyolefin-based barrier film with a renewable structure, where the melt blending temperature is 1-50 degrees C above the melting point of the higher melting point component of polyolefin and polymer A, temperature 1 is 1-150 degrees C below the melting point of polyolefin, temperature 2 is 30-200 degrees C above the glass transition temperature of polyolefin and the polymer A is polyglycolic acid, glycolic acid copolymer, vinyl alcohol copolymer, or thermoplastic starch. An INDEPENDENT CLAIM is also included for a polyolefin-based barrier film prepared as mentioned method.