Package making – Methods – Forming a cover adjunct or application of a cover adjunct to...
Reexamination Certificate
2000-02-01
2002-04-16
Rada, Rinaldi I. (Department: 3721)
Package making
Methods
Forming a cover adjunct or application of a cover adjunct to...
C053S451000
Reexamination Certificate
active
06370842
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a packaging material processing apparatus and to a method of producing packaging containers.
BACKGROUND ART
Conventional packaging containers have a spout for pouring liquid food contained therein. In order to form such a spout, a punch hole serving as a spout is formed in a packaging material used for forming a packaging container; an inner film is bonded to the packaging material from the reverse side in order to cover the punch hole; a pull-tab seal is bonded to the packaging material from the front side; and the inner film and the pull-tab seal are welded together through application of heat.
When the pull-tab seal is peeled off in order to open the packaging container, the inner film is ruptured together with the pull-tab seal. Thus, the spout is opened.
However, in the conventional packaging container, the peeled-off pull-tab seal is thrown away, resulting in environmental pollution.
To overcome this problem, there may be employed a packaging container in which a rupture area formed of a thin wall portion is defined at a spout portion of the packaging material which will become a spout. The packaging material can be easily ruptured upon application of an external force to the rupture area in order to open the spout.
However, the above-described packaging material has a layered structure in which a paper substrate layer, a gas barrier layer, and the like are sandwiched between an outermost layer and an innermost layer, which are formed of resin film such as polyethylene film. Therefore, when the spout is opened upon application of an external force, the resin film sometimes stretches, with the result that the resin film has ruptured portions and stretched portions coexisting in a mixed manner, and thus the rupture surface of the packaging material is roughened.
An object of the present invention is to solve the above-described problems of conventional packaging containers and to provide a packaging material processing apparatus and a method of producing packaging containers, which apparatus and method prevent roughening of a rupture surface of a packaging material that is formed upon opening of a spout through application of an external force.
DISCLOSURE OF THE INVENTION
To achieve the above object, a packaging material processing apparatus of the present invention comprises: transport means for transporting a layered packaging material that is formed of a paper substrate and resin films and that has a rupture area at a location corresponding to that of opening means; a seal unit for sealing the packaging material; and heating means disposed on the upstream side of the seal unit in the transport direction of the packaging material such that the heating means is opposed to an innermost layer of the packaging material in order to heat the packaging material.
In this case, after being heated and melted, the resin film of the packaging material is gradually cooled. As a result, thermoplastic resin that constitutes the resin film is crystallized and becomes brittle.
Accordingly, when an external force is applied to the rupture area by use of the opening means to thereby open a spout, the resin film does not stretch. As a result, the packaging material can be easily ruptured, and the rupture surface of the packaging material is prevented from being roughened, because the resin film does not have ruptured and stretched portions coexisting in a mixed manner.
In another packaging material processing apparatus of the present invention, the heating means has a plurality of hot-air jetting openings formed in a surface that faces the packaging material.
A method of producing packaging containers according to the present invention comprises the steps of: feeding a layered packaging material that is formed of a paper substrate and amorphous resin films and that has a rupture area at a location corresponding to that of opening means; sealing the packaging material in the longitudinal direction to form a tubular packaging material; charging contents into the tubular packaging material; sealing the tubular packaging material transversely at predetermined intervals and cutting the tubular packaging material at transversely sealed portions to form a container having a preliminary shape; folding, along folding lines, the container having a preliminary shape into a final shape; and attaching a lid member to the rupture area.
Further, the method comprises the steps of heating a portion, including at least the rupture area, of the resin film of the packaging material by heating means at an upstream location in a predetermined processing zone; and gradually cooling the portion of the resin film heated by the heating means at a downstream location in said processing zone in order to bring that portion into a crystalline state.
In another method of producing packaging containers according to the present invention, at least one of the resin films constituting the layered packaging material is formed of a thermoplastic resin that reversibly changes state between an amorphous state and a crystalline state.
In still another method of producing packaging containers according to the present invention, the above-described cooling is performed by natural heat radiation within a chamber of a charging apparatus.
In still another method of producing packaging containers according to the present invention, the above-described heating means continuously heats a strip-shaped portion of the packaging material including the rupture area.
In still another method of producing packaging containers according to the present invention, the above-described heating means selects and intermittently heats the rupture area of the packaging material.
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Katsumata Shigeo
Kumeta Yukihisa
Moriyama Yasuyuki
Huynh Louis
Lorusso & Loud
Rada Rinaldi I.
Tetra Laval Holdings & Finance S.A.
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