MEHRSCHICHTEGER BLASGEFORMTER GEGENSTAND

摘要

The technical challenge is to provide a multi-layer blow-molded article comprising a plurality of types of thermoplastic resins wherein the layers are strongly secured to each other without separating under normal service conditions, and the layers and/or portions defined in a circumferential direction, both of which have diverse resins, can be easily separated from each other in recycling or reuse. There is provided a multi-layer blow-molded article wherein in a multi-layer marginal-wall region foamed of a plurality of layers, a convexly crooked portion projecting generally convexly from inside to outside is so formed that the molding shrinkage factor of a resin for use in a more outer layer is larger than that of a resin for use in a more inner layer, and a concavely crooked portion denting generally concavely from outside to inside is so formed that the molding shrinkage factor of a resin for use in a more outer layer is smaller than that of a resin for use in a more inner layer; and all the layers of the molded article are fittingly secured to each other by means of a clamping force resulting from the difference in molding shrinkage factors of the resins constituting the layers and/or portions defined in a circumferential direction in the multi-layer marginal-wall region. The present invention may find extensive application in the field of large industrial parts such as automobile bumpers.