Technical Field
[0001] The present invention relates to a sealed bag with unsealing tape. More specifically
this invention relates to a sealed bag with unsealing tape provided on the opening-part
side of a packaging bag used for packaging foods, drugs or the like therein.
Background Art
[0002] Conventionally, bags (chuck bags) enable to be easily opened and closed by forming
a zipper (an engaging device), which includes a male member and a female member, in
an opening-part thereof have been used in many fields such as foods, drugs, daily
commodities, and the like. Even with the bag with a zipper as described above, it
is desirable that the bag is kept in the completely sealed state until the time point
of sales, and generally an end part there of is completely sealed along the zipper
part. In a case of a bag with a zipper which is completely sealed, generally a section
between the zipper and a seal part in the opening-part side of the bag is cut in,
and then the bag is opened and resealed at the zipper part.
[0003] For opening a sealed bag, a user generally cuts the bag with the conventional type
of scissors or tears a part to be cut in with hands from an end part thereof. To facilitate
the operation of tearing the part to be cut in with hands, sometimes a notch is formed
at a side edge of the bag.
[0004] However, use of scissors is messy, and in addition, if scissors are not available,
the bag can not be opened, which is disadvantageous. When a bag is torn from the notch,
the bag can not be cut in along a straight line, which is also disadvantageous. To
overcome the problems as described above, recently there has been proposed, for instance,
the following means as a means for tearing a bag along a straight line manually and
without using any tool such as scissors.
Means 1: Formation of a perforated line as a line for tearing on the opening-part
side
Means 2: Use of laminated film with the inner surface film relatively thick for forming
a bag, and formation of a zipper on the inner surface film as well as a perforated
line in a part outer from the zipper formed on the inner surface film and closer to
an edge of the bag (Refer to Japanese Utility Model Publication No. S52-18254).
Means 3: Formation of a cutting-plane line having a specific form (Refer to Japanese
Utility Model Publication No. S62-13838)
[0005] However, each of the means described above has the problems as described below.
[0006] With the means 1, the sealing performance is rather low because of the use of a perforated
line, and sometimes the bag employing the means I may be opened during transportation
or in other similar situations.
[0007] With the means 2, an inner surface side film with a perforated line formed thereon
itself can be tone along a straight line, but when the inner surface side film is
thermally fused and stuck to the base film, the perforations are filled with materials
from the base film due to the thermal effect, which disadvantageously makes it difficult
to tear the bag.
[0008] With the means 3, the sealing performance is insufficient, and in addition the process
for forming a specific cutting-plane line is disadvantageously complicated.
Disclosure of the Invention
[0009] A main object of the present invention is to provide a sealed bag with unsealing
tape which can provide the excellent sealing performance before its use and also which
can easily be cut in and unsealed manually.
[0010] The present invention provides a sealed bag with unsealing tape provided on an opening-part
side of a packaging bag, and the sealed bad according to the present invention comprises
band-shaped unsealing tape provided on one inner surface side of the bag and stuck
there to in parallel to the opening part of the bag, and is characterized in that
a cutout part is formed at an end part of the unsealed tape of the packaging bag on
a surface opposite to the side on which the unsealed tape is stuck.
[0011] Adhesion of the unsealing tape is carried out by using an adhesive or thermally,
for instance, by heat-sealing. The tape of the present invention is not limited to
the one with the large width, but can be the one with the small width, and even be
the one having a form like a string so long as the tearing guide effect can be obtained.
Tape with the relatively smaller width is preferable because the tearing guide effect
is higher. However, when the width is large, the higher tensile strength can be obtained
even if the thickness is small. When the width is small, the high strength can be
obtained by making the thickness larger, and the so-called string-formed tape having
an oval or circular cross section may be used in the present invention.
[0012] With the present invention as described above, band-shaped unsealing tape is stuck
on one inner surface of a packaging bag in parallel to the opening part thereof, and
a perforated line or the like is not provided, and because of the configuration, there
is not a space communicating to the outside, so that the excellent sealing performance
before the packaging bag is opened is provided without fail.
[0013] Further, a cutout part is formed on a surface opposite to the surface with the unsealing
tape stuck thereon at an end part of the unsealing tape of the packaging bag, therefore
the cutout part is present on one surface of the packaging bag as well as on one surface
of the unsealing tape, so that the end part of the unsealing tape is exposed in the
cutout part and the cutout par can easily be raised.
[0014] In the sealed bag with unsealing tape according to the present invention, it is preferable
to form, on the packaging bag and/or on the unsealing tape, a pair of cut-in parts
each cut in from an end part of the unsealing tape with the terminating edge present
at a position inner from the end part of the unsealing tape.
[0015] With the present invention as described above, as a pair of cut-in parts are formed
on the packaging bag and/or at end parts of the unsealing tape, a section between
the cut-in parts functions like a tab, and the tab-formed section can be pinched as
it is when unsealing the packaging bag, so that the operation for manually cut-in
and unsealing the bag can easily be performed.
[0016] In the sealed bag with unsealing tape according to the present invention, the cut-in
parts are preferably arranged diagonally against the unsealing tape with the base
edges of the cut-in parts arranged outside the unsealing tape.
[0017] With the present invention as described above, as the cut-in part are inclined, even
if a position at which the unsealing tape is stuck is slightly displaced from the
regular position, cut-in parts can be formed correctly on one surface of the packaging
bag as well as on the unsealing tape without fail. Especially, the pair of cut-in
parts get closer in a direction toward the depth of the bag ( in which cutting-in
is performed), so that the cut-plane line can be guided to a specified position (such
as a center line of the unsealing tape), and a desired and correct cut-plane line
can be acquired without fail, even if the work for cutting in is performed manually.
[0018] In the sealed bag with unsealing tape according to the present invention, the unsealing
tape is preferably drawn uniaxially in the longitudinal direction.
[0019] Herein the term of "drawing" means physically drawing a polymeric material into the
fiber-like or film-formed state. With this operation, the strength or elasticity modulus
of the polymeric material can be improved, and when a crystalline polymer is drawn
at a temperature higher than the glass transition temperature but lower than the melting
point, molecules in the non-crystalline portion are drawn in the drawing direction
with the crystallinity improved and the molecules are oriented in the drawing direction.
As a result, the tensile strength and elasticity modulus become larger. Uniaxially
drawing herein indicates drawing in one direction, and for instance, when a film is
drawn uniaxially, the strength in the drawing direction becomes stronger than that
in the vertical direction to provide an anisotropic material, and when the material
is torn, the directivity for being torn in the drawing direction becomes higher.
[0020] Because of this feature, the draw ratio should be 5 times or more, and preferably
in the range from 8 to 12 times. As the unsealing tape is uniaxially drawn in the
longitudinal direction, the directivity in tearing becomes higher, and the bag can
be unsealed linearly in the longitudinal direction of the unsealing tape.
[0021] In the sealed bag with unsealing tape according to the present invention, the unsealing
tape is preferably made of polyolefin-based resin, and the polyolefin-based resin
is preferably polyethylene-based resin or polypropylene-based resin.
[0022] As the polyolefin-based resin, there can be enlisted polyethylene, polypropylene,
polybutene and the like.
[0023] As the polyethylene-based resin, there can be enlisted linear low density polyethylene
(LLDPE), high density polyethylene (HDPE), low density polyethylene (LDPE) or the
like.
[0024] As the polypropylene for producing polypropylene-based resin, there can be enlisted
homopolypropylene, random polypropylene, block polypropylene and the like.
[0025] Because of the features described above, the unsealing tape is made of polyolefin-based
resin, so that processing such as molding or drawing is performed easy because the
polyolefin-based resin has the thermoplasticity,
[0026] Further, the polyethylene-based resin is excellent in the dampproof capability, waterproof
capability, cold resistance, and chemical resistance, and is well adapted to use for
packaging a product in the liquid state.
[0027] Further, the polypropylene-based resin has the small specific gravity, so that the
resin can contribute to weight reduction of a packaging bag itself.
[0028] In the sealed bag according to the present invention, a zipper comprising a pair
of male and female members is preferably stuck to both inner surfaces of the bag.
[0029] Because of the feature, a zipper comprising a pair of male and female members is
stuck to both inner surfaces of the bag, and the zipper can repeatedly be opened or
closed, so that the sealing performance of the bag can be maintained.
Brief Description of Drawings
[0030]
Fig. 1 is a flat view showing a packaging bag according to one embodiment of the present
invention;
Fig. 2 is an enlarged flat view showing a packaging bag according to the embodiment;
Fig. 3 is a cross-sectional view of the packaging bag taken along the line X-X in
Fig. 2;
Fig. 4 is a view showing the procedure for opening the packaging bag according to
the embodiment;
Fig. 5 is a view showing the procedure for producing the packaging bag according to
the embodiment; and
Fig. 6 is a flat view showing a packaging bag according to another embodiment of the
present invention.
Best mode for Carrying out the Invention
[0031] Embodiments of the present invention are described below with reference to the related
drawings.
[0032] Fig. 1 shows a packaging bag 1 according to one embodiment of the present invention.
[0033] The packaging bag 1 comprises polyethylene sheets 10A (top side in the figure), 10B
(rear side in the figure) sealed along the four edges thereof by means of heat sealing
or the like. These sealed portions form a heat-sealed part 12. One edge of the rectangular
packaging bag 1 functions as an opening part 2.
[0034] Unsealing tape 3 is wide tape made of polyolefin-based resin and is welded to the
opening part 2 side on a surface of the polyethylene sheet 10B by heat sealing or
the like, and is drawn uniaxially in the longitudinal direction.
[0035] A cutout part 4 is formed at an end part of the unsealing tape 3 of the packaging
bag 1 on the opening part 2 side on a surface of the polyethylene sheet 10A and has
a rectangular form.
[0036] A cut-in part 5 is formed at an end part of the unsealing tape 3 and is inclined
from the polyethylene sheet 10B against an edge of the unsealing tape 3 so that the
cut-in part 5 extends to inside of the unsealing tape 3. Further the cut-in part 5
is formed within a range of the cutout part 4. It is to be noted that the cutout part
4 and cut-in part 5 are provided both on heat-sealed parts 12 of two edges perpendicular
to the opening section 2 in this embodiment.
[0037] A zipper 11 comprises a pair of a male member and a female member, which are stuck
by heat sealing or the like under the unsealing tape 3 on the opening part 2 side
to the polyethylene sheets 10A, 10B respectively. The zipper 11 is stuck to an inner
surface of the packaging bag 1. The zipper 11 is made of polyethylene.
[0038] As shown in Fig. 2, the cutout part 4 is formed on the opening part 2 side and on
a surface of the polyethylene sheet 10A and has a rectangular form, while the cut-in
part 5 is positioned at an end part of the unsealing tape 3 in the outer side from
the unsealing tape 3, and inclined from a cut-in part base end 5A positioned on the
polyethylene sheet 10B, and extends to a cut-in part end part 5B positioned in the
inner side from the unsealing tape 3.
[0039] The cut-in part end part 5B is formed in the inner side from the unsealing tape 3
as shown in Fig. 3 which is a cross-sectional view taken along the line X-X in Fig.
2.
[0040] As for the procedure for unsealing the packaging bag 1, as shown in Fig. 4, an end
part of the unsealing tape 3 is pinched up, and then is pulled in the direction indicated
by the arrow in the figure to tear the packaging bag 1. The section in which the polyethylene
sheet 10B, unsealing tape 3, and polyethylene 10A are overlaid on each other is linearly
torn from the cut-in part end part 5B in a direction parallel to the unsealing tape
3.
[0041] As for the procedure for manufacturing the packaging bag 1, as shown in Fig. 5, at
first, the unsealing tape 3 is held between the polyethylene sheets 10A, 10B. The
cutout part 4 is formed at a position corresponding to the unsealing tape 3 on the
polyethylene sheet 10A. The polyethylene sheets 10A, 10B, and the unsealing tape 3
are heated, melted and stuck to each other by a heat seal bar 20, and a heat-sealed
part 12 is formed at a position corresponding to the cutout part 4.
[0042] Then two sets of cut-in parts 5 widening toward the end and each extending over an
edge of the unsealing tape 3 are formed within the cutout parts 4. In this step, the
two sets of cut-in parts 5 widening toward the end are opposite to each other.
[0043] The section in which the polyethylene sheet 10B, unsealing tape 3, and polyethylene
sheet 10A are overlaid on each other is cut in with a cut-in part bar 30 between the
two sets of cut-in parts 5.
[0044] With the steps described above, the polyethylene sheets 10B with the two sets of
cutout parts 4 and cut-in parts 5 formed thereon, unsealing tape 3, and polyethylene
sheets 10A are laminated to form a laminated body, and heat-sealed parts are formed
along two edges each perpendicular to the heat-sealed part 12 shown in the figure,
thus a packaging bag being formed.
[0045] With the embodiment as described above, the advantages as described below are provided.
(1) The cut-in parts 5 inclining against edges of the unsealing tape 3 and extending
to inside of the unsealing tape 3 are formed at an end part of the unsealing tape
3, and the cut-in parts 5 can be pinched as they are as a finger grip, so that the
operation of manually unsealing the bag can easily be performed.
[0046] Further, as the cut-in parts 5 are inclined, therefore even if the unsealing tape
3 is stuck at a position slightly displaced from the regular position, the cut-in
parts 5 can be formed without fail on a surface of the polyethylene sheet 10B of the
packaging bag 1 as well as on the unsealing tape 3.
[0047] In addition, the packaging bag 1 comprises the band-shaped unsealing tape 3 which
is stuck on one inner surface of the packaging bag 1 in parallel to the opening part
2, and a perforated line or the like is not required to be formed thereon, so that
a space communicating to the outside is not generated, which ensures the sealing performance
before the packaging bag 1 is unsealed.
(2) The cutout part 4 is formed on an inner surface opposite to that on which the
unsealing tape 3 is stuck at an end part of the unsealing tape 3 of the packaging
bag 1, and therefore the cutout part 4 is present only on the unsealing tape 3 and
on the polyethylene sheet 10A of the packaging bag 1, so that the cutout part 4 is
thin and the cut-in part 5 can easily be raised.
(3) The unsealing tape 3 is uniaxially drawn in the longitudinal direction, and the
directivity in tearing becomes higher, so that the packaging bag 1 can linearly be
unsealed in the longitudinal direction of the unsealing tape 3.
[0048] The present invention is not limited to the embodiment described above, and modifications
and improvements in a range in which objects of the present invention can be achieved
are encompassed within a scope of the present invention. For instance, although the
cut-in part 5 inclines from the cut-in part base end 5A positioned in the outer side
from the unsealing tape 3 and extends to the cut-in end parts 5B positioned in the
inner side from the unsealing tape 3, the present invention is not limited to this
configuration, and the cut-in part 5 may have the cut-in part base end 5A positioned
in the inner side from the unsealing tape 3.
[0049] In this case, the cut-in part 5 may not incline, and the pair of cut-in parts may
be, for instance, parallel to each other as shown in Fig. 6.
[0050] Although the cutout parts 4 and cut-in parts 5 are formed at both end parts of the
unsealing tape 3 respectively in the embodiment described above, the configuration
is allowable in which the cutout part and the cut-in part are formed only at one end
part (namely, only in the right or left side of the bag shown in Fig. 2 and Fig. 6).
[0051] It is not always necessary to form the pair of cut-in pasts 5, and it is possible
to pinch only the polyethylene sheet 10B and unsealing tape 3 with the cutout part
4, and therefore the work for tearing can easily be started by pinching this section.
[0052] The unsealing tape 3 is not limited to that having a relatively large width as described
in the embodiment above, and also the unsealing tape having a small width may be used,
and even the unsealing tape 3 like a string may be used so long as the tensile strength
providing the tearing guide effect can be obtained.
[0053] Further, the zipper 11 is stuck to the opening part 2 side in the embodiment described
above, but may not be provided. In this case, the packaging bag is adapted to be used
as a disposable bag.
[0054] The unsealing tape 3 is made of polyethylene in the embodiment described above, but
the material is not limited to polyethylene, and the unsealing tape 3 may be made
of polypropylene.
[0055] In addition, structures, forms and the like for carrying out the present invention
may be different from those described above within the range in which the object of
the present invention can be achieved.
Industrial Availability
[0056] The present invention can be applied to packaging bags for packing foods, drugs,
and the like therein, especially as a sealed bag with unsealing tape, an opening part
side of which can easily be unsealed.