Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1998-06-05
2003-04-01
Nolan, Sandra M. (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C206S824000, C220S062130, C220S062220, C229S087080, C428S036910, C428S037000, C428S043000, C428S138000, C428S423100, C493S212000, C493S377000, C493S930000, C493S933000, C493S963000
Reexamination Certificate
active
06541086
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a packing or wrapping film which is provided with an aluminum foil or the like as an intermediate layer and which is hard to break or tear but to easily be openable. The present invention also relates to a packing bag and a package body manufactured by using such packing film.
In a known art, there is provided a packing bag which is manufactured by heat-sealing a composite film formed by laminating a polyethylene film to a cellophane, paper or the like material, and since such packing bag is easily openable by hands along the heat seal portion without using any cutting means, such bag has been widely used. However, such composite film has low rupture strength and, particularly, has an insufficient moisture-proof property, so that there is a limitation to a content to be sealed in the packing bag manufactured by using such composite film.
In order to eliminate such defect, there has also been provided a laminate film, having improved rupture strength and moisture-proof property, formed by combining different kinds of plastic films. Such plastic laminate film has been widely utilized for manufacturing various packing bags, for example, for a material for a package (pouch or bag) or a material for a tubular package for containing sausage, sweet jellied bean-paste or the like.
It is difficult to open by hands the packing bag formed by using the plastic laminate film as a packing material because the plastic laminate film has a certain tearing strength, and in order to easily open such packing bag, a V-shaped or I-shaped notch is formed to the heat-seal portion of the packing bag.
Furthermore, one prior art example of a packing bag manufactured by using the plastic laminate film is shown in U.S. Pat. No. 3,608,815, in which, in order to open the bag from a bent(or folded) portion of the bag, an opening assisting area is formed to the bent portion by penetrating a pin to this bent portion and the bag is opened by hands at the opening assisting area as opening (cut) starting portion.
Still furthermore, the applicant of the subject application has been proposed a packing bag manufactured by using the plastic laminate film. The bag is formed with a bent(or folded) portion from which the bag is openable. In order to facilitate the opening from the bent portion, a plastic laminate film formed by laminating an oriented plastic film having a coarse surface and a non-oriented plastic film having a flat surface is used so that the coarse surface is positioned at the portion of the bag to be bent to open the bag from this bent portion.
However, the prior art techniques mentioned above provide the following defects or drawbacks.
In a case where the packing bag formed with the notch such as the V-shaped notch to the heat seal portion is manufactured by a packing material working maker and then supplied to a user, the notch forming working to the heat seal portion of the packing bag can be done by the working maker at the packing bag forming process, there is no problem for forming the notch to the heat seal portion. However, in a case where the packing material working maker supplies a packing material in roll form to a user and the manufacturing of the packing bag is performed by the user while filling a content in the bag by using a packing machine, it is difficult for the user side to form the notch to the heat seal portion of the packing bag.
Furthermore for the packing bag formed with the opening assisting area at the bent portion by penetrating a pin, it As not necessary to use a jig such as cutter for opening the bag and the bag can be easily opened by hands. However, the formation of the pin penetration hole degrades water-vapor permeability and oxygen permeability as such packing bag. Accordingly, such packing bag is not usable for packing, for example, such a content as coffee powders, rice crackers or the like which will be easily damaged by the moisture, thus limiting contents to be packed, being disadvantageous.
Still furthermore, with the packing bag formed by the plastic laminate film composed of the oriented plastic film having the coarse surface portion and the non-oriented plastic film having the flat surface in a manner such that the coarse surface portion of the oriented plastic film is covered with the flat surface of the non-oriented plastic film, the water-vapor permeability and the oxygen permeability are hardly degraded as the packing bag, so that there is no limitation of thee content to be sealed therein in a shelf-life time period. However, the packing bag of this type is not sufficient for the specific use as a bag capable of substantially completely shutting off moisture and oxygen or for sealing a retort food.
In a view point of reservation of the inner content, it will be preferred to use a laminate film, which is composed of oriented plastic films and an intermediate aluminum foil disposed between these plastic, films, for the material of the packing bag for reserving the inner content for a long term or containing the retort food. However, the packing bag formed of such plastic laminate film is hard to tear, so that it is often difficult to open the bag from the bent portion thereof.
Taking the above matters into consideration, the applicant of the subject application has provided a packing bag suitable for keeping the inner content in a good condition for a long time or for containing the retort food by using a plastic film material which is composed of an oriented plastic film having a coarse surface portion, a non-oriented plastic film having a flat surface, and an aluminum foil or paper sheet disposed between the oriented and non-oriented plastic films.
The laminate film of this structure has a good openability and a good shelf life property. However, in a view point of the shelf life, it is preferred to dispose the aluminum foil between the oriented plastic films.
Moreover, the packing bag formed from She plastic laminate film material with an aluminum foil or paper sheet being interposed between plastic films has a defect such that a value for commercial product is lowered or degraded because of a fear that when the oriented plastic film having the coarse surface portion and the aluminum foil is laminated by using a binder(or an adhesive), a component of the binder may be intruded into through holes formed to the coarse surface portion and leaks to an outer surface of the oriented plastic film. When the binder leaks on the surface of the plastic laminate film, a guide roller guiding the plastic film may be contaminated with the leaked binder when packing bags are continuously manufactured, and furthermore, when the laminated film of the oriented plastic film and the aluminum foil is rolled, a blocking phenomenon may be caused to the rolled continuous laminated film, providing a troublesome problem.
Furthermore, it is generally difficult to tear, by hands, the bonded portion of the tubular package body in which sausage or the like is sealed as an inner content because such package body is required to have a high tearing strength, and hence, it is required to use a jig such as cutter for opening such package body. In this regard, a package body having a heat seal portion from which the package is easily opened by hands has been proposed.
In a package body formed of a plastic laminate film, it is possible to easily open the package by attaching an opening tape having a fine width to the heat seal surface and drawing the opening tape. However, the attaching of the fine tape to the heat seal surface of the package requires an additional working process, which will result in a complicated manufacturing process and a cost increase.
SUMMARY OF THE INVENTION
In view of the defects or drawbacks encountered in the prior art mentioned above, a first object of the present invention is to provide a packing film, which is composed of oriented plastic films laminated on both surfaces of an aluminum foil or paper sheet as an intermediate layer, and further provided with an opening starting portion capable of be
Moteki Yoshiji
Ohshima Shigeyuki
Yamazaki Shokichi
Hosokawa Yoko Co., Ltd.
Nolan Sandra M.
Parkhurst & Wendel L.L.P.
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