COMPOSITE STRUCTURE MEMBER, MANUFACTURING METHOD THEREOF, AUTOMOTIVE MEMBER, AND AUTOMOBILE DOOR PANEL

摘要

PROBLEM TO BE SOLVED: To provide a composite structure member whose outer wall and foaming layer are sufficiently closely adhered, and which is excellent in heat resistance and rigidity.SOLUTION: The composite structure member constituted of a foaming layer derived from a primary foaming particle and the outer wall closely adhered with the foaming layer is manufactured by a manufacturing method comprising a step of filling the primary foaming particle of a polylactic acid resin in a space constituted by the outer wall, and heating the primary foaming particle to secondary foam the primary foaming particle, wherein the outer wall has an inner surface constituted of a material necessitating no adhesive and closely in contact with the foaming layer, and has a hole through which a gas generated by the secondary foaming can pass; the primary foaming particle has a crystallization degree of 15 to 35%; and the foaming layer has an increased crystallization degree of 40 to 50% on the heating.