Bottles and jars – Multilayer barrier structure
Patent
1996-10-08
1998-09-01
Weaver, Sue A.
Bottles and jars
Multilayer barrier structure
215 122, 215370, 220453, 425531, B65D 102, B65D 2302, B29C 4948, B29C 4950
Patent
active
057998094
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a blow molded container with a featured bottom sealing portion and a blow mold used for the blow molding.
BACKGROUND ART
It is known that a bottom sealing portion formed by pinch-offs of the mold is projected to strengthen the bottom sealing portion of a single-layer or multi-layer blow molded container (for example, Japanese Published Unexamined Utility Model Application No. H03-3460, Japanese Utlity Model Publication No. H06-11164).
Such a container with a projected bottom sealing portion has higher bond strength than a normal type. However, when the container is a plastic container made of material providing weak pinch-off portions against drop impact such as polyethylene terephthalate or polypropylene or when the container is a large-volume plastic container, there is a problem of cracking in the bottom sealing portion when the container drops down with the content therein.
A multi-layer blow molded container, of which an inner layer and an outer layer can be freely separated from each other to completely pour out the content, is well known (see, for example, Japanese Published Unexamined Patent Application No. H05-310265).
In the conventional container, when pouring out the content, the outer layer is maintained in the container's profile while the inner layer is deformed due to the depressurization. Therefore, air is entrapped into the separated part between the outer layer and the inner layer.
However, since air is entrapped from a slit formed between the edges of the outer layer at the bottom pinch-off portion, the container also entraps moisture when the container is used in a damp area such as a bathroom. In addition, there is a problem that the decrease in the content can not be viewed.
Then, a container with a slit formed in the outer layer at the upper side and of which the inner layer and the outer layer are bonded at the bottom pinch-off portion has been proposed. However, since the container must be made of resin with low bond strength in order to separate the outer layer and the inner layer from each other, the cracking of the bottom sealing joint and the occurrence of slit due to the separation between layers cannot be prevented with the conventional configuration of the bottom pinch-off portion.
To overcome the aforementioned problems, it is a first object of this invention to provide a blow molded container with strengthened bottom sealing portion and a blow mold used for the blow molding and it is a second object of this invention to provide a separable multi-layer plastic container in which the bottom sealing portion is improved not to entrap moisture from the bottom by the above technique and the inner layer can be smoothly separated to completely consume the contents.
DISCLOSURE OF INVENTION
The present invention comprises as follows to achieve the aforementioned objects.
The container of the present invention is formed by blow molding in which a parison comprising a cylindrical resin material is heated and inflated by fluid.
The mold has pinch-offs for holding the parison and fusion-bonding one of resin layers to the other one so as to form a bottom sealing portion of the container and for pinching off the residual resin.
The bottom sealing portion formed by the pinch-offs has a projection projecting outwardly and downwardly from the container and sunk portions formed in one of the resin layers constituting said projection such a manner as to be buried in the other resin layer.
Since the mold pinches the cylindrical parison, the bottom sealing portion is formed as a strip-like projection projecting outwardly and downwardly from the bottom of the container and extending along a parting line of the mold.
Since the bottom sealing portion is provided with the sunk portions, the resin layers constituting the bottom sealing portion which are bonded together are engaged with each other.
Since the resin layers are bonded in the engaged state with the sunk portions formed in the respective resin layers, the bonded area between the resi
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patent: 3561629 (1971-02-01), Turner
patent: 3592885 (1971-07-01), Goins et al.
patent: 3687593 (1972-08-01), Gilbert
patent: 3692453 (1972-09-01), Quigg
patent: 3758654 (1973-09-01), Martino
patent: 5316135 (1994-05-01), Kneer et al.
Hisama Hiroyuki
Honda Masato
Sako Isamu
Sato Jyoji
Seguchi Masato
Weaver Sue A.
Yoshino Kogyosho Co. Ltd.
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