Method for producing a polyolefin structure

A method for producing a polyolefin-based structure from a mixed source material comprising 60 to 90% by mass of a polyolefin (A), 5 to 35% by mass of an acid-modified polyolefin (B) and 5 to 35% by mass of a gas barrier resin (C) composed of polyamide, using a molding machine, wherein:

• the molding machine is equipped with a single-screw extruder which has a screw running inside a cylinder, a die head, and a communication portion for feeding the mixed source material from the single-screw extruder to the die head, and
• the mixed source material is extruded out through the molding machine under the temperature condition satisfying the following (1) to (4) to give a polyolefin-based structure in which the gas barrier resin (C) is dispersed in a form of layers in the polyolefin (A):
• Am+10° C.≤T1≤Cm−10° C. (1)
• Cm−30° C.≤T2≤Cm+30° C. (2)
• Cm−10° C.≤T3≤Cm+50° C. (3)
• Cm−30° C.≤T4≤Cm+30° C. (4)
• wherein T1 is a cylinder temperature in a section corresponding to a supply zone and a compression zone of the screw in the single-screw extruder;
• T2 is a cylinder temperature in a section corresponding to a metering zone of the screw in the single-screw extruder;
• T3 is a temperature of the communication portion;
• T4 is a temperature of the die head;
• Am is a melting point of the polyolefin (A);
• and Cm is a melting point of the gas barrier resin (C).