The present invention is a double-walled container manufacturing method in which when a pair of partial molds is brought towards each other to be assembled to form a split mold, at least a portion of the mating surfaces of the pair of partial molds clamp a parison at two side portions that are at horizontal positions facing each other. The method is able to manufacture the container easily with a molding device that does not differ significantly from the past and, in a double-walled container obtained from a relatively rigid outer container and a flexible inner container the volume of which can change according to the amount of contents filled inside said outer container, an opening for introducing outside air can be formed very easily and reliably at a lower cost than the processing cost of prior art.

A plural preform assembly having nested preforms. The preforms are held together by an interference fit. The interference fit is provided by the friction between the preforms which occurs when the inner preform is inserted into the outer preform. At least one preform may have ribs extending radially towards the other preform. The ribs provided concentricity and interference to hold the preforms together during subsequent operations. The preforms may later be blow molded to provide a bag in bottle or similar container.

In a method of producing an automobile fuel tank including a tank body, an outer wall of the tank body being formed of a synthetic resin layer composed of a multilayer configuration, wherein the synthetic resin layer includes an inner body layer and an outer body layer with at least a barrier layer interposed therebetween, and the inner body layer includes a structural member with an air space internally provided, the method includes: forming the outer wall of the inner body layer, the outer body layer, and the barrier layer which is interposed between the inner body layer and the outer body layer, exclusive of the structural member; and welding the structural member only to an inner face of the inner body layer.

A plural preform assembly having nested preforms. The preforms are held together by an interference fit. The interference fit is provided by the friction between the preforms which occurs when the inner preform is inserted into the outer preform. At least one preform may have ribs extending radially towards the other preform. The ribs provided concentricity and interference to hold the preforms together during subsequent operations. The preforms may later be blow molded to provide a bag in bottle or similar container.

A blown bottle includes at least two layers including an inner layer and an outer layer, wherein the inner layer includes an inner layer flange, the outer layer includes an outer layer flange, and wherein a protrusion is formed on either one of the inner layer flange or the outer layer flange, a recess is formed in the other, and the protrusion is fitted to the recess.

A plural preform assembly having nested preforms with an inner preform and an outer preform. The preforms are sealably joined together, defining a volume between the preforms. Propellant is disposed in the volume between the preforms. The preforms are later blow molded to provide a bag in bottle, bottle in bottle or similar container. The propellant charge is already present when blow molded, preventing the need for a later propellant filling step.

Methods of making containers are provided, including providing a material sheet having at least two barrier layers and at least two polymer layers, forming the material sheet into a tube, sealing the tube at a seal area, and blow molding the tube to form a container in which the at least two barrier layers form a substantially continuous barrier at the seal area.

A plural preform assembly having nested preforms with an inner preform and an outer preform. The preforms are sealably joined together, defining a volume between the preforms. Propellant is disposed in the volume between the preforms. The preforms are later blow molded to provide a bag in bottle, bottle in bottle or similar container. The propellant charge is already present when blow molded, preventing the need for a later propellant filling step.

The invention relates to a co-extruded film comprising a sealing layer of low density polyethylene and a skin layer, wherein the skin layer comprises a copolyamide which comprises: At least 75 wt % monomeric units derived from caprolactam; Between 5 to 25 wt % monomeric units derived from a diamine and terephthalic acid; wherein the weight percentage is with respect to the total weight of copolyamide in the skin layer. The invention also relates to a process for preparing such a film, as well as applications of the film.

A preform, a synthetic resin container, and a method for manufacturing a synthetic resin container in which an air passage leading from an ambient air introduction hole to a trunk can be easily preserved. In the mouth, the inner body includes a large-diameter portion provided at an upper end thereof, and a small-diameter portion continuously extending below the large-diameter portion via a connecting portion. In the mouth, the outer body is provided with an ambient air introduction hole passing through the outer body, and a neck ring positioned within a height range of the small-diameter portion. The inner body is made of a crystalline resin, and a crystallized region is formed in part of the inner body, the crystallized region having a higher degree of crystallization than other regions.