Method for producing mixed composition

A method for producing a mixed composition comprising a lignocellulosic fiber and a molten thermoplastic resin that are kneaded together, the mixed composition being for use as a fiber reinforced resin material,

• the method comprising:
• a kneading step of kneading the lignocellulosic fiber and the thermoplastic resin together using a multi screw extruding machine equipped with two or more screws,
• wherein the multi screw extruding machine includes:
• a cylinder that internally has a kneading space in which the screws are provided;
• and
• a heating device that is provided on an outer circumferential portion of the cylinder and includes a plurality of heating units arranged in an axial direction of the cylinder, and
• the kneading step includes:
• a high temperature kneading step;
• and a low temperature kneading step performed after the high temperature kneading step, when a heating region that can be heated by the heating device of the multi screw extruding machine is divided into a plurality of sections in the axial direction of the cylinder, each section including one or more of the plurality of heating units,
• the high temperature kneading step being the step of kneading the lignocellulosic fiber and the thermoplastic resin together while maintaining the set temperature of the one or more heating units in at least one of the plurality of sections at a temperature greater than or equal to a melting point of the thermoplastic resin to obtain a mixture of the lignocellulosic fiber and the molten thermoplastic resin, and
• the low temperature kneading step being the step of kneading the mixture while maintaining the set temperature of the one or more heating units in at least one of the plurality of sections at a temperature less than the melting point of the thermoplastic resin.