Envelopes – wrappers – and paperboard boxes – Paperboard box – With closure for an access opening
Reexamination Certificate
2001-01-25
2002-04-23
Elkins, Gary E. (Department: 3727)
Envelopes, wrappers, and paperboard boxes
Paperboard box
With closure for an access opening
C220S359200, C229S123200
Reexamination Certificate
active
06375067
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a packaging container.
BACKGROUND ART
In a conventional packaging container for accommodating, for example, liquid food, a lid member made of a resin is welded to the top wall of a container body and is used to repeatedly open and close a discharge opening that is formed upon opening the packaging container.
For such a purpose, a rupturable portion is formed, through reduction of the thickness of a packaging material, in a discharge opening portion that is defined on the top wall at a predetermined position.
Accordingly, when a lid portion of the lid member is rotated, the rupturable portion is ruptured and thus the packaging container is opened.
FIG. 1
is a perspective view of a conventional container body;
FIG. 2
is a cross-sectional view of a main portion of the conventional container body;
FIG. 3
is a perspective view of a second conventional container body; and
FIG. 4
is a cross-sectional view of a main portion of the second conventional container body.
In
FIGS. 1 and 2
, reference numeral
50
denotes a packaging material;
51
denotes a container body formed of the packaging material
50
and having the shape of, for example, an octagonal prism;
52
denotes a top wall of the container body
51
; and
53
denotes a rupturable portion formed in a discharge opening portion which is defined on the top wall
52
at a predetermined position. The rupturable portion
53
is formed through reduction of the thickness of the packaging material
50
.
Reference numeral
55
denotes a lid member made of a resin and welded to the top wall
52
. The lid member
55
has a main body portion
56
, and a lid portion
57
, which is swingably supported by the main body portion
56
via an unillustrated hinge.
The packaging material
50
comprises an outer layer
61
, a paper substrate
62
, a bonding layer
63
, a barrier layer
64
, a bonding layer
65
, and an inner layer
66
, which are formed in this sequence from the outside to the inside of the packaging container. The outer layer
61
, the bonding layers
63
and
65
, and the inner layer
66
are typically formed of a resin such as polyethylene or an ethylene copolymer. The outer layer
61
and the inner layer
66
are preferably formed of low-density polyethylene. The barrier layer
64
is formed of aluminum foil or the like. If necessary, printing is performed on the outer surface of the outer layer
61
or the outer surface of the paper substrate
62
. In a process for producing the packaging material
50
, a hole
68
is punched in the paper substrate
62
at a portion corresponding to the rupturable portion
53
. Therefore, the rupturable portion
53
is formed of the outer layer
61
, the bonding layers
63
and
65
, the barrier layer
64
, and the inner layer
66
, so that the rupturable portion
53
is thinner than the remaining portion by an amount corresponding to the thickness of the paper substrate
62
.
Further, since the lower surface of the lid portion
57
is bonded to the rupturable portion
53
, when the lid portion
57
is pulled up and rotated, the rupturable portion
53
is ruptured, so that the packaging container is opened. In place of the lid member
55
, a pull-tab sheet may be used.
In
FIGS. 3 and 4
, reference numeral
50
denotes a packaging material;
51
denotes a container body;
52
denotes a top wall of the container body
51
; and
73
denotes a rupturable portion. The rupturable portion
73
is formed through formation of perforations
76
surrounding a predetermined portion of the packaging material
50
.
Reference numeral
75
denotes a lid member made of a resin and welded to the top wall
52
. The lid member
75
has a main body portion
56
, and an opening flap
77
, which is swingably supported by the main body portion
56
via an unillustrated hinge.
The packaging material
50
comprises an outer layer
61
, a paper substrate
62
, a bonding layer
63
, a barrier layer
64
, a bonding layer
65
, and an inner layer
66
, which are formed in this sequence from the outside to the inside of the packaging container. In a process for producing the packaging material
50
, perforations
76
are formed in the paper substrate
62
at a portion corresponding to the rupturable portion
73
.
In this case, when the opening flap
77
is rotated about the hinge, the rupturable portion
73
is pulled up from the container body
51
. As a result, the rupturable portion
73
is ruptured, and the packaging container is opened.
However, in the conventional packaging container having the rupturable portion
53
formed by thinning the packaging material
50
, the outer layer
61
and the bonding layer
63
are difficult to bond together over the entire rupturable portion
53
, with the result that pinholes are apt to be generated in an increased area at a bent portion of the outer layer
61
; i.e., at the circumferential edge of the punched hole
68
.
When the area where pinholes are apt to be generated increases, air becomes likely to enter the interior of the container body
51
via the pinholes, resulting in deterioration in the quality of the packaging material
50
.
In the conventional packaging container having the rupturable portion
73
formed through formation of the perforations
76
surrounding a predetermined portion of the packaging material
50
, since the strength of the rupturable portion
73
is high, the packaging container cannot be opened unless the rupturable portion
73
is pulled up from the container body
51
.
Accordingly, the types of usable lid members are limited.
In view of the foregoing problems involved in the above-mentioned conventional packaging containers, an object of the present invention is to provide a packaging container which can improve the quality of a packaging material and which does not restrict the types of usable lid members.
DISCLOSURE OF THE INVENTION
To achieve the above objects, a packaging container according to the present invention comprises a container body and a lid member welded to a top wall of the container body. The lid member is composed of a main body portion having an opening and a lid portion swingably supported by the main body portion.
A rupturable portion is formed in a discharge opening portion which is defined on. the top wall at a predetermined position. The rupturable portion is composed of a thin-wall portion and a rupture-line area. The thin-wall portion is formed through reduction of the thickness of the packaging material, which constitutes the container body. The rupture-line area is formed through formation of a rupture line portion surrounding a predetermined area. When the lid member is attached to the container body, the lower surface of the lid portion is bonded to the predetermined area at at least a portion adjacent to the thin-wall portion.
In this case, since the lower surface of the lid portion is bonded to the predetermined area at a portion adjacent to the thin-wall portion, when the lid portion is pulled up and rotated, the rupturable portion is ruptured, so that a discharge opening is formed in the discharge opening portion, and the packaging container is thus opened.
Since the area of the thin-wall portion can be decreased by an amount corresponding to the area of the rupture-line area, the area at the inner circumferential edge of the punched hole where pinholes are apt to be generated can be decreased.
Accordingly, the amount of air that enters the interior of the container body via pinholes can be decreased, resulting in an improvement in the quality of the packaging material.
Further, since the strength of the rupturable portion can be decreased by an amount corresponding to the area of the thin-wall portion, the types of usable lid members are not restricted.
In another packaging container according to the present invention, the rupture-line portion is formed of perforations.
In still another packaging container according to the present invention, the rupture-line portion is formed of a half-cut line portion.
REFERENCES:
patent: 4189060 (1980-02-01), Trotm
Elkins Gary E.
Lorusso & Loud
Tetra Laval Holdings & Finance S.A.
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