A double container includes: an outer layer body including an outer mouth portion and a barrel portion; an inner layer body including an inner mouth portion and a containing portion; an outside air introduction port for introducing outside air; and a plurality of vertical ribs arranged with spacing in a circumferential direction on an inner surface of the outer layer body or an outer surface of the inner layer body, and each extending over the outer mouth portion to the shoulder portion or extending over the inner mouth portion to the containing portion, wherein at least one of the plurality of vertical ribs faces the outside air introduction port.

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 preform is provided for blow-molding to form a container. The preform includes a finish portion for rotatably engaging a closure to seal contents within an interior of the container. The finish portion comprises a cylindrical body that begins at an opening to the interior and extends to and includes a tamper evidence ledge. A bevel at a beginning of the opening receives a plug seal of the closure. A sealing surface adjacent to the bevel is disposed along an interior of the finish portion and includes a polished buffer zone to cooperate with the plug seal to seal the container. A transition surface extends from the sealing surface to a handling surface that receives equipment to form the preform into the container. In some embodiments, the transition surface includes a polished buffer zone to cooperate with an end of the plug seal to seal the contents in the container.

A preform assembly for producing a container includes an external preform and an internal preform, each configured to form respectively an external drum and an internal bag of the container. The internal preform can be internally associated with the external preform along a central longitudinal axis so as to define a hollow space with the external preform.

The part under the neck ring (9) of a preform for blowing a PET bottle of predetermined capacity not larger than 75 cl and with a max. material weight of 15 g, is inclined by an angle less accentuated than normal, max. 17, which allows to make a preform with a thickness t.sub.2 of the wall thinner than 1.9 mm and a thinner inner diameter of the preform body in order to allow a lower stretch ratio starting from a larger preform to obtain the final bottle of predetermined capacity.

A preform assembly includes: an outer preform that includes an outer mouth portion and a stretch portion connected to the outer mouth portion and in which a recess extending in a vertical direction is provided on an inner surface of the stretch portion; and an inner preform that includes an inner mouth portion and a stretch portion connected to the inner mouth portion, wherein an outside air introduction port communicating with a part between the outer preform and the inner preform is provided in a mouth portion composed of the outer mouth portion and the inner mouth portion located on an inner side of the outer mouth portion.

A dual-structure container including an inner bag container (31) and an outer container (41) obtained by simultaneous stretch-blow molding according to a stack preform method using an inner bag container preform (1) and an outer container preform (3). On a body (33) of the inner bag container (31), contraction-control thin portions (50) are formal at a plurality of sites at intervals in the circumferential direction such that the thin portions (50) extend like strips in the axial direction.

A synthetic resin delamination container formed by blow molding a preform assembly having an outer preform and an inner preform, at least either one of an inner surface of the outer preform and an outer surface of the inner preform being applied with a release agent. The delamination container has: an outer layer body including an outer mouth portion and a bottomed tubular body portion being continuous with the outer mouth portion; an inner layer body including an inner mouth portion and a volume-reducible and deformable storage portion peelably laminated on an inner surface of the body portion through a release agent layer formed by the release agent; and an outside air introduction port configured to introduce outside air between the outer layer body and the inner layer body, in which an applying amount per unit area of the release agent layer is 10 to 850 mg/m.sup.2.

An aerosol dispenser, an outer container for an aerosol dispenser, and a preform for an outer container. The aerosol dispenser, outer container, and preform each have a neck including a crimp ring. The crimp ring may be configured to receive a valve cup, which is clinched thereto. The crimp ring includes one or more vents. The vents may be used to control overpressurization within the dispenser. The vents may be exposed to pressurized propellant and product due to deformation of the neck during undue overpressurization. The vents allow propellant and/or product to be released therethrough in the event of overpressurization.

Disclosed are preforms which incorporate improvements in the region of the neck and upper segment of the body to allow the production of lightweight containers, such as bottles suitable for containing water or other beverages. In accordance with certain embodiments, the improvements include a thinner neck finish area than conventional bottles, where the thinner area is extended into the upper segment of the body portion below the support ring. Reducing the thickness in these areas of the bottle allows for less resin to be used in forming the preform and bottle.