Method for Producing Resin Composition

A method for producing a resin composition that includes a first component and a second component, wherein:

• the first component is a polymer, and
• the second component is organic fibers, or a combination of organic fibers with a polymer different from the first component,
• the method includes a kneading step in which the first component and the second component are kneaded with an extruder provided with a kneading zone including a pressure drop zone,
• the pressure drop zone is a location where the pressure of influent into the pressure drop zone is 0.5 to 20 MPa and the ratio of the pressure of effluent from the pressure drop zone with respect to the pressure of influent into the pressure drop zone is 0.2 or lower, and
• the content of the second component in the influent into the pressure drop zone is 15 to 90 mass %,
• wherein the organic fibers in the resin composition have a mean fiber diameter of 1000 nm or smaller and a mean fiber length/mean fiber diameter ratio of 30 or greater, the mean fiber diameter and the mean fiber length being measured by a scanning electron microscope (SEM).

A method for producing a resin composition that includes a first component and a second component, wherein:

• the first component is a polymer, and
• the second component is organic fibers, or a combination of organic fibers with a polymer different from the first component,
• the method includes a kneading step in which the first component and the second component are kneaded with an extruder provided with a kneading zone including a pressure drop zone,
• the pressure drop zone is a location where the pressure of influent into the pressure drop zone is 0.5 to 20 MPa and the ratio of the pressure of effluent from the pressure drop zone with respect to the pressure of influent into the pressure drop zone is 0.2 or lower, and
• in the kneading step, an additional polymer at a lower temperature than the mixture that has passed through the pressure drop zone is added to the mixture to cool the mixture,
• wherein the organic fibers in the resin composition have a mean fiber diameter of 1000 nm or smaller and a mean fiber length/mean fiber diameter ratio of 30 or greater, the mean fiber diameter and the mean fiber length being measured by a scanning electron microscope (SEM).

A method for producing a resin composition that includes a first component and a second component, wherein:

• the first component is a polymer, and
• the second component is organic fibers, or a combination of organic fibers with a polymer different from the first component,
• the method includes a kneading step in which the first component and the second component are kneaded with an extruder provided with a kneading zone including a plurality of high-pressure zones at a pressure of 0.1 MPa or higher, and
• the pressure [P1] in the highest-pressure zone having the maximum pressure among the plurality of high-pressure zones is 0.5 MPa or higher, and the ratio [P1/P2] of the pressure [P1] with respect to the average value [P2] for the pressure of the high-pressure zones other than the highest-pressure zone is greater than 1 and 100 or lower,
• wherein the ratio [P1/P3] of the pressure [P1] with respect to the pressure [P3] of each high-pressure zone other than the highest-pressure zone is greater than 1 and 100 or lower.