TECHNICAL FIELD

The present disclosure relates to a synthetic resin delamination container formed by blow molding a preform assembly in which an inner preform is incorporated inside an outer preform.

BACKGROUND

As a container that contains food seasonings such as soy source, beverages, cosmetics, shampoo, rinse, liquid soap and the like as a content liquid, a synthetic resin delamination container (laminated peeling container) is known. The delamination container is formed in a double structure by blow molding a preform assembly in which an inner preform is incorporated inside an outer preform. The delamination container has: an outer layer body including a tubular outer mouth portion and a bottomed tubular body portion being continuous with the outer mouth portion; and an inner layer body including a tubular inner mouth portion disposed inside the outer mouth portion and a volume-reducible and deformable storage portion peelably laminated on an inner surface of the body portion.

Such a delamination container is used, for example, as a squeeze type dispensing container combined with a spout cap having a check vale or a container with a pump combined with a pump, and can dispense a content liquid to the outside by squeezing a body portion of the outer layer body or by operating a pump. On the other hand, after a content liquid is dispensed, only a storage portion of the inner layer body can be reduced in volume and deformed while the outer layer body is restored to its original shape or is maintained by introducing the outside air between the inner layer body and the outer layer body from an outside air introduction port provided at the outer layer body. Therefore, with a delamination container, a content liquid contained in the storage portion of the inner layer body is dispensed to the outside without being replaced with the outside air. Thus contact of the outside air with a content liquid contained in the inner layer body is reduced, and deterioration and change in quality of the content liquid can be suppressed.

However, since an existing delamination container is formed by blow molding a preform assembly in which an inner preform is incorporated inside an outer preform, an outer surface of the storage portion of the inner layer body strongly adheres to an inner surface of the body portion of the outer layer body due to high pressure and heat during the blow molding. As a result, a peeling resistance of the storage portion with respect to the body portion increases, and there is a problem that it is possible that the storage portion may cause insufficient peeling when a content liquid is dispensed. In particular, when the body portion is formed in a bottle shape having a shoulder portion, a main body portion and a bottom portion and the outside air introduction port is formed as a through hole passing through the outer mouth portion of the outer layer body in the radial direction, the storage portion is hard to be peeled off at the shoulder portion, and the outside air introduced from the outside air introduction port is not supplied to the main body portion. As a result, a function as a delamination container may not be exhibited.

Further, when both the outer layer body and the inner layer body are each made of polyethylene terephthalate resin, the peeling resistance of the storage portion with respect to the body portion further increases. Therefore, in addition to the above described problem, when the body portion is squeezed as a content liquid is dispensed, the outside surface of the storage portion rubs against the inner surface of the body portion and creaks, which causes a problem of unusual sense of touch of the body portion.

In order to address the above described problems, for example, Patent Literature 1 (PTL 1) discloses a delamination container, in which heat-resistant silicone oil is previously applied to at least either one of the inner surface of the outer preform and the outer surface of the inner preform to provide a release agent layer formed of heat-resistant silicone oil between the inner surface of the body portion and the outer surface of the storage portion. In this manner the peeling resistance of the storage portion with respect to the body portion is reduced.

CITATION LIST

Patent Literature

PTL 1: JP5168572 (B2)

SUMMARY

Technical Problem

However, as the delamination container disclosed in PTL 1, when a preform assembly in which heat-resistant silicone oil is previously applied to at least either one of the inner surface of the outer preform and the outer surface of the inner preform is blow molded, moldability of a container in blow molding is decreased depending on the applying amount of the release agent. Thus, a delamination container of a desired shape may not be obtained, or creaks generated between the storage portion and the body portion may not be sufficiently reduced.

The present disclosure has been made in view of the above described problems, and it is an object of the present disclosure to provide a delamination container that has a storage portion peeled off easily from the body portion and can be precisely molded into a predetermined shape.

Solution to Problem

A disclosed delamination container is a synthetic resin delamination container formed by blow molding a preform assembly having an outer preform and an inner preform incorporated inside the outer 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 a tubular outer mouth portion and a bottomed tubular body portion being continuous with the outer mouth portion; an inner layer body including a tubular inner mouth portion disposed inside the outer 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, wherein an applying amount per unit area of the release agent layer is 10 to 850 mg/m2.

In the delamination container configured in the above described manner, preferably, the outside air introduction port is a through hole passing through the outer mouth portion in the radial direction.

In the delamination container configured in the above described manner, preferably, the body portion has a shoulder portion being continuous with a lower end of the outer mouth portion, a tubular main body portion being continuous with a lower end of the shoulder portion and a bottom portion configured to close a lower end of the main body portion, in which the release agent layer is provided in an area corresponding to the shoulder portion and the main body portion, and is not provided in an area corresponding to the bottom portion.

In the delamination container configured in the above described manner, the outer layer body and the inner layer body are each made of polyethylene terephthalate resin.

Advantageous Effect

According to the present disclosure, a delamination container that has a storage portion peeled off easily from a body portion and can be precisely molded into a predetermined shape can be provided.

