Laminated synthetic resin bottle, injection molding device, and process for molding a laminated preform

A laminated synthetic resin bottle formed through biaxially drawing and blow molding a laminated synthetic resin preform in a shape of a test tube, the preform including at least one intermediate layer of an intermediate-layer resin is laminated between a plurality of substrate layers of a main resin over a predetermined height range, the bottle comprising:

• a plurality of substrate layers of a main resin;
• a plurality of intermediate layer segments of an intermediate-layer resin, the intermediate layer segments being laminated between the substrate layers and being formed over a predetermined height range, the intermediate layer segments and the substrate layers being non-adhered to each other;
• a plurality of narrow vertical connecting zones formed of the substrate layers being welded directly with each other, the narrow vertical connecting zones not having the intermediate layer segments disposed between the substrate layers, the narrow vertical connecting zones being formed in parallel in a circumferential direction and along a longitudinally axial direction of the bottle, and the narrow vertical connecting zones being disposed on either side of each intermediate layer segment, wherein
• the intermediate layer segments are segmented in the circumferential direction by the narrow vertical connecting zones.