Abstract: The present invention provides a laminated-parison extrusion-molding apparatus which includes a head body; a multi-ring structure having a spider provided in the head body; a head core provided inside the multi-ring structure; an outer cylinder member provided surrounding a lower outer periphery of the multi-ring structure, the outer cylinder member constituting a lower portion of the head body; and an annular member provided inside the outer cylinder member, wherein an outer main material is supplied to a flow passage provided between the outer cylinder member and the annular member so as to achieve an outer main material layer having a uniform thickness.

Abstract: An extrusion molding apparatus includes a die head with first, second, third and fourth annular nozzles. An adhesive extruder is connected to the first and third nozzles, a barrier extruder is connected to the second nozzle and a reclaimed material extruder is connected to the fourth nozzle. Inner and outer main material flow passages are connected to a main material extruder, as well. The annular nozzles and the main material flow passages are connected to an extrusion nozzle for forming a parison. The barrier material extruder has a cylinder which is connected to the second nozzle. A screw lies within the cylinder. The second nozzle has a ridge opposite an end of the screw, for dividing the extruded barrier flow material, mitigating stagnation of the barrier material as it passes through the second nozzle. A method of forming a parison is described, as well.

Abstract: A multilayer parison extruder includes a cylinder; an annular piston movably fitted in the cylinder; a material accumulation chamber in which the piston is moved; a material conduction chamber communicating with the accumulation chamber; an annular multilayer head provided in the conduction chamber; and a die slot provided under the conduction chamber. The extruder further includes a main material extruder for supplying a main material to the accumulation chamber; and auxiliary material extruders for supplying the auxiliary materials to the multilayer head. The extruder is characterized in that pairs of opposed feed ports are provided in the multilayer head and communicate with the auxiliary material extruders. At least one pair of the inlet ports is provided for each of a pair of arc-shaped passages which are for the auxiliary materials.

Abstract: Extrusion molding equipment for a multi-layer parison which includes an accumulator head, a cylindrical member disposed in the accumulator head and having a temperature control device for controlling a chief resin material temperature wise, a ringed piston reciprocable along the inner peripheral surface of the cylindrical member, a core member coaxially disposed inside the ringed piston and at least one ringed member coaxially disposed within an annular resin passage defined between the cylindrical member and the core member, into which resin passage the chief resin material is forcibly supplied from an accumulator composed of the ringed piston and a hydraulic cylinder operating the ringed piston, with one or more annular nozzles being defined in the ringed member for extruding one or more auxillary resin materials.