BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a packaging bag with
a zipper.
Description of the Related Art
A conventional packaging bag with zipper of this kind
is known from Utility Model Registration No. 2557256, for
example. In other words, a packaging bag is conventionally
known wherein an openable and closable zipper which
performs a male and female coupling action is provided at
opposing positions of a bag in the vicinity of the opening
end thereof, and in an integral fashion with the bag.
In a packaging bag of the kind disclosed in Utility
Model Registration No. 2557256 described above, which
comprises an integrally provided openable and closable
zipper performing a male and female coupling action, in
most cases of a packaging bag with zipper which is not
provided with a slider, the perimeter of the bag, including
the edge adjacent to the opening end of the bag close to a
location of the zipper, is closed by heat sealing. Thus,
the bag cannot be opened by opening the zipper unless the
heat seal section along the edge adjacent to the opening
end of the bag is cut. There are also such bags, however,
that are not heat sealed along the edge adjacent to the
opening end of the bag close to the location of the zipper.
Such bags can simply be opened by opening the zipper at a
shop display cabinet, for instance. If the bag is then
closed again after opening, it cannot be identified whether
or not it has been opened, posing management problems.
Furthermore, in the case of a packaging bag with
zipper that is provided with a slider, the zipper is
provided along the opening end of the bag and a slider is
provided movably in the longitudinal direction of the
zipper, making it impossible to close the opening end of
the bag by heat sealing. Hence similar management problems
arise with this kind of packaging bags with zipper that are
provided with a slider.
SUMMARY OF THE INVENTION
The present invention was devised to resolve the
problems, an object thereof being to make it possible
readily to identify whether or not a packaging bag with
zipper has been opened.
In order to achieve the object, the present invention
is devised as follows:
A packaging bag with zipper, in which the lower end
portion of a male zipper tape and the lower end portion of
a female zipper tape are bonded to the inner faces of
respective front side and rear side sheet sections, or rear
side and front side sheet sections, along the opening end
of the bag. The upper end of the bag comes at the top when
the bag is in an upright state, and the respective zipper
tapes are bonded together at a position below the engaging
section thereof, with heat sealing strength of a degree
that allows the zipper tapes to be manually peeled apart,
by means of an interface peeling action, an interlayer
peeling action, or a cohesive peeling action.
In the packaging bag with zipper, either one of the
zipper tapes is made from a hot melt type adhesive resin,
and the other zipper tape is made from a polyethylene type
resin or a polypropylene type resin of the same kind as a
material forming the inner layers of the bag.
In the packaging bag with zipper, either one of the
zipper tapes is made from a hot melt type adhesive resin,
and both the outer face and the inner face of the other
zipper tape are made from a polyethylene type resin or a
polypropylene type resin of the same kind as a material
forming the inner layer of the bag.
In the packaging bag with zipper, one of the zipper
tapes is made from a hot melt type adhesive resin, the
outer face of the other zipper tape is made from a
polyethylene type resin or polypropylene type resin of the
same type as the material forming the inner layers of the
bag, and the inner face of the other zipper tape is made
from a polyethylene type resin or polypropylene type resin
of a different type from the material forming the inner
layers of the bag.
In the packaging bag with zipper, the inner faces of
both zipper tapes are made from a polyethylene type resin
or polypropylene type resin, and a hot melt type adhesive
resin section is provided on the inner face of one of the
zipper tapes, at least in a bonding section formed by heat
sealing in a position below the engaging section of the
zipper tapes.
In the packaging bag with zipper, a hot melt type
adhesive resin section that is to be bonded to the inner
layer of the bag, is provided in at least the lower end
portion of the outer face of the zipper tape made from a
polyethylene type resin or a polypropylene type resin.
In the packaging bag with zipper, both zipper tapes
are made from a resin containing a material comprising a
random mixture of a straight-chain low-density polyethylene
type resin and a polybutene-1 resin.
In the packaging bag with zipper, a resin section
containing a material comprising a random mixture of a
straight-chain low-density polyethylene type resin and a
polybutene-1 resin is provided on the inner faces of both
zipper tapes, at least in the bonding section formed by
heat sealing below the engaging section of the zipper tapes.
In the packaging bag with zipper, the male zipper tape
and the female zipper tape are respectively coloured with
mutually different colours.
According to the foregoing, zipper tapes are bonded
together at a position below the engaging section of the
zipper tapes, with heat sealing strength that allows the
bonding section of the zipper tapes to be peeled apart by
hand. Thus, if a user has mistakenly opened the zipper and
peeled apart the bonding section of the zipper tapes, for
example, it will be possible to confirm that the packaging
bag has been opened. In particular, by colouring the male
zipper tape and the female zipper tape, respectively with
mutually different colours, the bonding section of the
zipper tapes can be changed to a separate colour, by means
of colour mixing, and if a user has mistakenly opened the
zipper and peeled apart the bonding section of the zipper
tapes, for example, the colour of the section will revert
to the original colours of the respective zipper tapes.
Thus, it is easy to identify whether or not the packaging
bag has been opened.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view of a packaging bag with
zipper according to a first embodiment of the present
invention;
Fig. 2 is an enlarged sectional view of a principal
part of this packaging bag with zipper;
Fig. 3 is an enlarged sectional view of the principal
part of this packaging bag with zipper, showing the bag in
an open state;
Fig. 4 is an enlarged sectional view of a principal
part of a packaging bag with zipper according to a second
embodiment, showing the bag in an open state;
Fig. 5 is an enlarged sectional view of a principal
part of a packaging bag with zipper according to a third
embodiment, showing the bag in an open state; and
Fig. 6 is an enlarged sectional view of a principal part of
a packaging bag with zipper according to a fourth
embodiment, showing the bag in an open state.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In Fig. 1 to Fig. 3, numeral 1 denotes a packaging bag,
and this packaging bag 1 is closed by heat sealing at three
edges, namely, the lower end when the bag is in an upright
state, and the two respective side edges. Numeral 2
denotes the heat seal section of the bag. Zipper tapes 5,
6 are provided in an integral fashion at the opening end of
the bag which comes at the top when the packaging bag 1 is
in an upright state, by heat sealing and bonding the lower
end portion of a male zipper tape 5 and a female zipper
tape 6 to the inner faces of respective sheet sections 3, 4
on the front side and rear side (or rear side and front
side) of the bag 1. In other words, the zipper tapes 5 and
6 are provided in such a manner that they project from the
upper end of the packaging bag 1.
The sheet sections 3, 4 forming the packaging bag 1
have a two-layer structure in which the outer layers 3a, 4a
thereof are made from nylon film and the inner layers 3b,
4b are made from polyethylene film, and the male zipper
tape 5 and female zipper tape 6 which are bonded to the
inner faces of these respective sheet sections 3, 4 along
the opening end of the packaging bag 1 are made from
materials described below.
For example, taking the material of the male zipper
tape 5 as A and the material of the female zipper tape 6 as
B, then A is a hot melt type adhesive resin and B is a
polypropylene type resin, and a polyethylene type resin
layer 7 and a hot melt type adhesive resin layer 8 are
formed respectively by combined extrusion on the material A
forming the male zipper tape 5 and material B forming the
female zipper tape 6, on the faces thereof which oppose the
inner faces 3b, 4b of the respective sheet sections 3, 4.
Thereupon, if the male zipper tape 5 and the female zipper
tape 6 are heat sealed, respectively, onto the inner face
of the sheet section 3 and the inner face of the sheet
section, at a temperature of 180ºC, for example, a sealing
time of one second, and a sealing pressure of 20 N/cm2,
then the polyethylene type resin layer 7 of the zipper tape
5 and the inner layer 3b of the polyethylene film of the
sheet section 3 fuse together, and the hot melt type
adhesive resin layer 8 of the zipper tape 6 fuses with the
inner layer 4b of the polyethylene film of the sheet
section 4. In this case, the polyethylene type resin layer
7 of the zipper tape 5 and the polyethylene film of the
inner layer 3b of the sheet section 3 are of the same type
and become completely fused together, and the hot melt type
adhesive resin layer 8 of the zipper tape 6 and the
polyethylene film of the inner layer 4b of the sheet
section 4 are bonded together by a heat sealing strength of
approximately 5 N/15 mm. In other words, it was found on
the basis of experimentation, that the hot melt type
adhesive resin has characteristics whereby, when heated, it
bonds with polyolefin type resins, such as polyethylene,
and has a heat sealing strength with polyolefin type resins
of 5 N/15 mm or above.
Furthermore, in the packaging bag 1 with zipper
according to the present embodiment, the respective zipper
tapes 5, 6 are bonded together by heat sealing along a
lower end in the width direction of the zipper portion when
the packaging bag 1 is in an upright state, in such a
manner that the zipper tapes can be peeled apart by an
interface peeling action. Numeral 9 denotes a bonding
section between the zipper tapes 5, 6. Since the material
of the zipper tape 5 is a hot melt type adhesive resin, and
the material of the zipper tape 6 is a polypropylene type
resin, the heat sealing strength will be approximately 5
N/15 mm described above. This heat sealing strength of
approximately 5 N/15 mm is of a degree that allows the
zipper tapes to be peeled apart readily by hand.
In the present embodiment, a blue colouring agent is
incorporated into the hot melt type adhesive resin which is
the material forming the zipper tape 5, and a yellow
colouring agent is incorporated into the polypropylene type
resin which is the material forming the zipper tape 6, so
that when the respective zipper tapes 5, 6 are in a state
of being bonded together by heat sealing, the colour of the
bonding section becomes green, due to the mixing of the
colours. Moreover, by fabricating both of the zipper tapes
5, 6 from a transparent material, and performing coloration
of the polyethylene type resin layer 7 and the hot melt
type adhesive resin 8 provided on the outer sides thereof,
using a blue colouring agent and a yellow colouring agent,
respectively, it is possible to make the colour of the
bonding section a green colour, by mixing the colours,
similarly to the foregoing, when the two zipper tapes 5, 6
are bonded together by heat sealing.
Since the engaging section 10 of the male zipper tape
5 and the female zipper tape 6 will deform if heat is
applied thereto, only the lower end portions of the
respective zipper tapes 5, 6 which overlap with the inner
faces of the sheet sections 3, 4, below the engaging
section 10, are bonded by heat sealing. In the drawings,
11 denotes a slider for opening and closing the zipper
tapes 5, 6.
Various types of hot melt type adhesive resin are
known, but in the present embodiment, it is possible to use,
as a resin suitable for bonding the zipper tapes 5, 6
together in such a manner that they can be peeled apart by
an interface peeling action, for example, a resin formed
from a resin composition comprising at least one type of
resin selected from a group comprising ethylene
ethylacrylate copolymer comprising a main ingredient of
ethylene vinyl acetate copolymer manufactured by Hirodine
Corp., and petroleum resins, turpentine resins and rosin
type resins.
Moreover, in the embodiment described above, the
material of the male zipper tape 5 is stated as a hot melt
type adhesive resin, and the material of the female zipper
tape 6 is stated as a polypropylene type resin, but a
reverse configuration is also possible. In this case, a
hot melt type adhesive resin layer is formed on the male
zipper tape 5, and a polyethylene type resin layer is
formed on the female zipper tape 6.
Furthermore, with respect to the shape of the
packaging bag 1, in addition to the embodiment described
above, it is also possible to use a gusset type, butt-seam
type, or standing pack type, or the like.
Moreover, in the embodiment described above, a slider
is provided on the zipper, but it is of course also
possible to implement the present invention with a zipper
having no slider.
As described above, in the present embodiment, a
product (a bag containing contents) is arranged in a store
display cabinet in a state in which the lower end sections
of respective zipper tapes 5, 6 are bonded together with
heat sealing strength of a degree that allows the bonding
section of the zipper tapes to be readily peeled apart by
hand, at the height of the bonding section of the tapes to
the sheet sections 3, 4 of the packaging bag 1. Thus, if a
user has mistakenly opened the zipper and peeled apart the
bonding section 9 of the zipper tapes 5, 6, the colour
(green) of the bonding section 9 will revert to the colours
of the respective zipper tapes 5, 6 (blue, yellow) or, if
the zipper tapes 5, 6 are transparent, it will revert to
the colours of the polyethylene type resin layer 7 and the
hot melt type adhesive resin layer 8 provided on the outer
sides thereof. Hence it will be possible to confirm that
the packaging bag 1 has been opened.
If the lower end sections of the zipper tapes 5, 6 are
bonded together in this manner with heat sealing strength
of a degree that allows the bonding section of the zipper
tapes to be peeled apart readily by hand, when a user buys
a product and goes to extract the contents from the bag 1,
he or she can extract the contents from the packaging bag 1
by opening the zipper and peeling apart the bonding section
9 between the zipper tapes 5, 6. In this case, the heat
sealing strength of the bonding section 9 between the
zipper tapes 5, 6 is approximately the same as the heat
sealing strength between the inner face of the packaging
bag 1 and the female zipper tape 6 that is made of a
polypropylene type resin and has a hot melt type adhesive
resin layer 8 provided on the surface thereof. But since
the bonding section 9 is situated at the lower end section
of the location of the zipper tapes, the female zipper tape
6 and the packaging bag 1 are not liable to be peeled apart
when the bonding section 9 is peeled apart by means of the
user's fingers.
In the present embodiment, the zipper tape 5 is
coloured blue and the zipper tape 6 is coloured yellow, in
such a manner that the heat-sealed bonding section becomes
green in colour, but it is also possible to use other
colour combinations. It is not necessarily required to
perform colouring of the zipper tapes 5, 6, and when the
bonding section 9 of the zipper tapes 5, 6 has been peeled
apart, it can be readily identified that the packaging bag
1 has been opened.
Moreover, in the embodiment described above, the two
zipper tapes 5, 6 are bonded together in such a manner that
they can be peeled apart by means of an interface peeling
action, with heat sealing strength of a degree that permits
the tapes to be peeled apart manually, at a position below
the engaging section 10 of the zipper tapes 5, 6. It is
also possible to bond the zipper tapes together by means of
an interlayer peeling action or a cohesive peeling action.
For example, as a hot melt type adhesive resin used for
forming a cohesive peel, it would be suitable to use a
polymer alloyed resin containing a polyolefin known as VMX
(registered trademark) manufactured by Mitsubishi Chemical
Corp. as a main ingredient. The polymer alloyed resin
essentially consists of a multi-component polymer including
a polyolefin resin which is grafted with a radical
polymerisation monomer and contains a non-crystalline vinyl
polymer in a uniform manner, and a polymer including
polyolefin dispersed with styrene in the dispersion phase
of polyolefin.
Furthermore, in the embodiment described above, the
packaging bag 1 is made from a synthetic resin fabricated
from sheet sections 3, 4 having a two-layer structure
comprising nylon film in the outer layers 3a, 4a and
polyethylene film in the inner layers 3b, 4b, but the
materials used are not limited in particular to these. In
other words, provided that, at the least, a synthetic resin
film such as a polyethylene film or a polypropylene film,
or the like, is used to fabricate the inner layers, due to
the requirements of heat sealing, it is possible to use a
material other than a synthetic resin, such as aluminium
foil, paper, rayon paper, or the like, as a material to be
laminated on the outer sides of the inner layers.
Moreover, in the embodiment described above, in the
male zipper tape 5 made from a hot melt type adhesive resin
and the female zipper tape 6 made from a propylene type
resin, a polyethylene type resin layer 7 and a hot melt
type adhesive resin layer 8 are formed respectively on the
faces opposing the inner layers 3b, 4b of the respective
sheet sections 3, 4 but whilst the hot melt type adhesive
resin layer 8 provided on the side of the female zipper
tape 6 made from a polypropylene type resin is required, it
is possible to omit the polyethylene type resin layer 7
provided on the side of the male zipper tape 5 made from a
hot melt type adhesive resin. Moreover, it is also
possible to make the male zipper tape or the female zipper
tape from a hot melt type adhesive resin, and to make the
other zipper tape from a polyethylene type resin, and in
this case, since the other zipper tape made from a
polyethylene type resin is of the same type as the
polyethylene film on the inner layer 3b of the sheet
section 3, it will fuse completely with same, and the
zipper tape made from a hot melt type adhesive resin and
the polyethylene film on the inner layer 4b of the sheet
section 4 will be bonded together by a heat sealing
strength of approximately 5 N/15 mm, similarly to the
embodiment described above. Moreover, the heat sealing
strength between the zipper tapes may also be approximately
5 N/15 mm, and the two zipper tapes may be bonded together
on the basis of an interface peeling action, as in the
embodiment described above, or a interlayer peeling action,
or a cohesive peeling action. Furthermore, a composition
may also be adopted wherein one of the zipper tapes is made
from a hot melt type adhesive resin, and the outer face of
the other zipper tape is made from a polyethylene type
resin, whilst the inner face thereof is made from a
polypropylene type resin which is different to the material
forming the inner layer of the packaging bag 1.
Furthermore, in the embodiment described above, the
zipper tapes 5, 6 are bonded by heat sealing to the inner
faces of the respective sheet sections 3, 4 of the
packaging bag 1, but it is also possible for the two zipper
tapes 5, 6 to be installed on the inner faces of the
respective sheet sections 3, 4 of the packaging bag 1 by
being laid respectively over the inner faces of the sheet
sections 3, 4 of the packaging bag 1 in a sheet state, and
bonded to same, whilst the zipper tapes 5, 6 are in a
molten state directly after molten extrusion.
Fig. 4 shows a second embodiment of the present
invention.
The second embodiment illustrated in Fig. 4 is a
modification of the first embodiment shown in Fig. 1 - Fig.
3. Whereas in the first embodiment, the male zipper tape 5
and the hot melt type adhesive resin layer 8 provided on
the outer face of the female zipper tape 6 are made
entirely from a hot melt type adhesive resin, in the second
embodiment, the male zipper tape 5 is made from a
polyethylene type resin of the same kind as the inner layer
3b of the packaging bag 1, and the female zipper tape 6 is
made from a polypropylene type resin, a section 12 made
from a hot melt type adhesive resin being provided on the
inner face of the male zipper tape 5 only in the vicinity
of the bonding section 9 between the zipper tapes 5, 6, and
a section 13 made from a hot melt type adhesive resin
bonded to the inner layer 4b of the packaging bag 1 being
provided on the outer face of the lower end section of the
female zipper tape 6. It is also possible to provide a
section made from a polyethylene type resin of the same
kind as the inner layer 4b of the packaging bag 1, instead
of the section 13 made from a hot melt type adhesive resin.
Even if a hot melt type adhesive resin section is provided
in a minimum necessary area at a position below the
engaging section 10 of the zipper tapes 5, 6 in this way,
similar effects to those of the first embodiment can still
be obtained. In this embodiment, if the male zipper tape 5
is made from a hot melt type adhesive resin, the section 12
made from a hot melt type adhesive resin can be omitted.
Fig. 5 shows a third embodiment of the present
invention.
In the third embodiment shown in Fig. 5, the male
zipper tape 5 and the female zipper tape 6 are both made
from a polyethylene type resin of the same type as forming
the inner layers 3b, 4b of the packaging bag 1, and a
section 14 made from a hot melt type adhesive resin is
provided on the inner face of the female zipper tape 6,
only in the vicinity of the bonding section 9 of the zipper
tapes 5, 6.
Furthermore, both the zipper tapes 5, 6 are made from
a resin containing a random mixture of a straight-chain
type low-density polyethylene resin and a polybutene-1
resin, for example, as means for bonding the zipper tapes 5,
6 together in a readily peelable manner, in a position
below the engaging section 10, with heat sealing strength
of a degree that allows the zipper tapes to be manually
peeled apart. Thus, the bonding section 9 along the lower
end section of the zipper tapes 5, 6 fabricated from the
foregoing material will not couple completely, and hence it
will be possible to peel apart the bonding section 9 of the
zipper tapes 5, 6, readily and manually, by means of a
cohesive peeling action.
Fig. 6 shows a fourth embodiment of the present
invention.
In the fourth embodiment shown in Fig. 6, both of the
zipper tapes 5, 6 are made from a polyethylene type resin
of the same type as forming the inner layers 3b, 4b of the
packaging bag 1, and resin sections 15, 16 containing a
resin comprising a random mixture of a straight-chain low-density
polyethylene type resin and a polybutene-1 resin
are provided on the inner faces of the two zipper tapes 5,
6 at least in the vicinity of the bonding section 9 located
below the engaging section 10 of the zipper tapes 5, 6.
This also causes the bonding section 9 in the lower end
section of the zipper tapes 5, 6 not to couple together
completely, and hence it will be possible to peel apart the
bonding section 9 of the zipper tapes 5, 6 readily and
manually by means of a cohesive peeling action.
In the embodiment illustrated in the drawings, the
respective zipper tapes 5, 6 may have a structure
comprising three or more layers. In other words, it is
possible to interpose between the inner face and the outer
face of the zipper tapes 5, 6, by using a adhesive resin, a
material other than a polyethylene type resin or a
polypropylene type resin, a hot melt type adhesive resin,
or a resin containing a random mixture of a straight-chain
type low-density polyethylene type resin and a polybutene-1
resin.
Furthermore, in the foregoing description, the bonding
section 9 of the zipper tapes 5, 6 is bonded with a heat
seal strength of approximately 5 N/15 mm, but it may be
sufficient if the heat sealing strength is 1 N/15 mm or
above.