U.S. patent application number 13/578713 was filed with the patent office on 2012-12-13 for zipper tape and packing bag with zipper tape.
This patent application is currently assigned to IDEMITSU UNITECH CO., LTD.. Invention is credited to Shuichi Goto, Michio Mogami, Tomohiko Tamaoki.
Application Number | 20120314978 13/578713 |
Document ID | / |
Family ID | 44367787 |
Filed Date | 2012-12-13 |
United States Patent
Application |
20120314978 |
Kind Code |
A1 |
Tamaoki; Tomohiko ; et
al. |
December 13, 2012 |
ZIPPER TAPE AND PACKING BAG WITH ZIPPER TAPE
Abstract
A thick portion is formed thick at an end of a female belt-like
base near a containing space. To the thick portion near the
containing space, a cut portion thinner than the female belt-like
base is provided. To the cut portion near the containing space, a
seal base that is thicker than the female belt-like base and is
sealed to an inner surface of a bag body to which a male belt-like
base is attached, is provided. Seal strength of the thick portion
to the inner surface is lower than that of the seal base. The cut
portion is provided to have a lower seal strength than that of the
seal base. An area surrounded by the thick portion, the cut
portion, the seal base and the inner surface becomes hermetically
sealed. Even when external pressure is applied on the bag body,
damages to the cut portion can be prevented.
Inventors: |
Tamaoki; Tomohiko;
(Sodegaura-shi, JP) ; Goto; Shuichi; (Chuo-ku,
JP) ; Mogami; Michio; (Sodegaura-shi, JP) |
Assignee: |
IDEMITSU UNITECH CO., LTD.
Tokyo
JP
|
Family ID: |
44367787 |
Appl. No.: |
13/578713 |
Filed: |
February 9, 2011 |
PCT Filed: |
February 9, 2011 |
PCT NO: |
PCT/JP11/52737 |
371 Date: |
August 13, 2012 |
Current U.S.
Class: |
383/97 ;
24/585.12 |
Current CPC
Class: |
Y10T 24/45168 20150115;
B65D 33/2525 20130101; B65D 33/2533 20130101 |
Class at
Publication: |
383/97 ;
24/585.12 |
International
Class: |
B65D 33/24 20060101
B65D033/24; A44B 19/26 20060101 A44B019/26 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 12, 2010 |
JP |
2010-029236 |
Claims
1. A zipper tape comprising: a pair of a male member and a female
member comprising: an engagement portion that is engageable and
disengageable and defines a containing space inside a bag body; and
belt-like bases that are continuously connected to the engagement
portion and are bondable to an inner surface of the bag body,
wherein a first one of the belt-like bases comprises: a thick
portion that is formed thicker than the first one of the belt-like
bases at an end near the containing space; a cut portion that is
continuously connected to the end of the thick portion near the
containing space and is formed thinner than the first one of the
belt-like bases; and a seal base that is continuously connected to
an end of the cut portion near the containing space, formed thicker
than the first one of the belt-like bases, and attached to the
inner surface of the bag body to which a second one of the
belt-like bases is attached, wherein the thick portion is attached
to the inner surface of the bag body to which the second one of the
belt-like bases is attached by a strength lower than a strength for
the seal base to be attached to the inner surface of the bag body,
and the cut portion is provided in a form of a belt spaced away
from the inner surface of the bag body, the cut portion isolating
the containing space from the outside and having a strength lower
than the strength for the seal base to be attached to the inner
surface of the bag body.
2. The zipper tape according to claim 1, wherein the thick portion
and the seal base are formed substantially in the same
thickness.
3. The zipper tape according to claim 1, wherein, the thick portion
is formed narrower toward the inner surface of the bag body.
4. The zipper tape according to claim 3, wherein a surface of the
thick portion and a surface of the seal base which face each other
across the cut portion are substantially parallel to each other and
are substantially orthogonal to the inner surface of the bag body
to which the thick portion and the seal base are attached.
5. A packaging bag with a zipper tape, comprising: a bag body
having an opening portion for defining a containing space; and the
zipper tape according to claim 1, the zipper tape being provided on
an inner surface of the bag body.
Description
TECHNICAL FIELD
[0001] The present invention relates to a zipper tape and a
packaging bag provided with the zipper tape.
BACKGROUND ART
[0002] There has typically been known a packaging bag with a zipper
tape (hereinafter, occasionally abbreviated as a packaging bag)
provided by bonding the zipper tape to an inner surface of the bag
body. When such a packaging bag is filled with powdery substances
and liquids as contents, the contents may leak toward a top seal
beyond the zipper tape during transportation. Accordingly, a zipper
tape with a separating structure provided between the zipper tape
and the contents and a packaging bag with the zipper tape have been
known for preventing leakage of the contents (see, for instance,
Patent Literatures 1 to 3).
[0003] The separating structure provided in the zipper tape is
exemplified by a cut portion, a part of which can be easily cut,
and a seal that is easily peelable from an inner surface of a bag
body. In opening the packaging bag, the cut portion is cut or
peeled to take out the contents.
[0004] Patent Literature 1 discloses a packaging bag including a
wide seal base provided to a belt-like base of a male member near
the contents. The seal base includes a linear cut portion. The
packaging bag is sealed by the linear cut portion being bonded to
an end of a belt-like base of a female member. The linear cut
portion is cut by a force in opening the zipper tape, thereby
opening the packaging bag.
[0005] Patent Literature 2 (e.g., FIG. 10) discloses that a thin
and linear cut portion is provided in a belt-like base of a male
member near the contents and the cut portion is cut to open a
packaging bag.
[0006] Patent Literature 3 discloses that a connecting portion is
provided as a cut portion by connecting ends of
non-opening-side-flanges of a male member and a female member of a
joint to each other and the connecting portion is cut to open the
packaging bag. Patent Literature 3 also discloses that a protrusion
having a triangular cross section is formed on each of the ends of
the male member and the female member, thereby allowing a stress to
concentrate on the cut portion.
CITATION LIST
Patent Literature(s)
[0007] Patent Literature 1 JP-A-2008-24324 [0008] Patent Literature
2 International Publication No. WO2004/050487 [0009] Patent
Literature 3 JP-A-2006-51987
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0010] In Patent Literatures 1 and 2, since the cut portion is
linearly formed, when sealing the belt-like bases or the seal base
of the male and the female members to the inner surface of the bag
body, it is difficult to position the seal base and the cut portion
at a right place. Accordingly, the cut portion may be directly
bonded to the inner surface of the bag body, or the belt-like base
and the seal base may be bonded to each other. In such a case,
cuttability of the cut portion may be impaired.
[0011] In such a structure as disclosed in Patent Literature 3,
unless at least one of the protrusions is fixed to a bag body film,
a sufficient force cannot be applied on the cut portion to open the
bag. Accordingly, it may be difficult to cut the cut portion.
[0012] An object of the invention is to provide an easily openable
and favorably sealable zipper tape and a packaging bag with the
zipper tape.
Means for Solving the Problems
[0013] According to an aspect of the invention, a zipper tape
includes: a pair of a male member and a female member including: an
engagement portion that is engageable and disengageable and defines
a containing space inside a bag body; and belt-like bases that are
continuously connected to the engagement portion and are bondable
to an inner surface of the bag body, in which a first one of the
belt-like bases includes: a thick portion that is formed thicker
than the first one of the belt-like bases at an end near the
containing space; a cut portion that is continuously connected to
the end of the thick portion near the containing space and is
formed thinner than the first one of the belt-like bases; and a
seal base that is continuously connected to an end of the cut
portion near the containing space, formed thicker than the first
one of the belt-like bases, and attached to the inner surface of
the bag body to which a second one of the belt-like bases is
attached, in which the thick portion is attached to the inner
surface of the bag body to which the second one of the belt-like
bases is attached by a strength lower than a strength for the seal
base to be attached to the inner surface of the bag body, and the
cut portion is provided in a form of a belt spaced away from the
inner surface of the bag body, the cut portion isolating the
containing space from the outside and having a strength lower than
the strength for the seal base to be attached to the inner surface
of the bag body.
[0014] In the above aspect of the invention, it is preferable that
the thick portion and the seal base are formed substantially in the
same thickness.
[0015] In the above aspect of the invention, it is preferable that
the thick portion is formed narrower toward the inner surface of
the bag body.
[0016] In the above aspect of the invention, it is preferable that
a surface of the thick portion and a surface of the seal base which
face each other across the cut portion are substantially parallel
to each other and are substantially orthogonal to the inner surface
of the bag body to which the thick portion and the seal base are
attached.
[0017] According to another aspect of the invention, a packaging
bag with a zipper tape includes: a bag body having an opening
portion for defining a containing space; and the zipper tape
according to any one of claims 1 to 4, the zipper tape being
provided on an inner surface of the bag body.
[0018] According to the invention, even if external pressure or
internal pressure of the bag is applied on the bag body with the
zipper tape attached and containing the contents in the containing
space, since a substantially hermetically sealed area is formed by
the thick portion, the cut portion, the seal base and the inner
surface of the bag body, the substantially hermetically sealed area
works as a pressure buffer area. Accordingly, even if the cut
portion is configured to be easily cut in opening, the cut portion
can be prevented from being stretched by external pressure or
internal pressure of the bag to impair sealability for separating
the containing space from the outside, particularly
water-tightness. Consequently, both a favorable openability and a
sufficient sealability can be obtained.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a front view showing a packaging bag with a zipper
tape according to a first exemplary embodiment of the
invention.
[0020] FIG. 2 is a cross section taken along the line II-II in FIG.
1 for showing engagement of a male member and a female member.
[0021] FIG. 3 is an enlarged cross section of a seal base of the
zipper tape in FIG. 2.
[0022] FIG. 4 is a cross section showing disengagement of the male
member and the female member in FIG. 2.
[0023] FIG. 5 is a cross section showing when a cut portion is cut
to open the bag in FIG. 2.
[0024] FIG. 6 is a cross section showing how contents are sealed in
the packaging bag with the zipper tape.
[0025] FIG. 7 is a perspective view showing seal bars used for
sealing the contents.
[0026] FIG. 8 is a partially cut perspective view showing how the
contents are sealed with the seal bars.
[0027] FIG. 9 is an enlarged perspective view showing an enlarged
zipper tape in a packaging bag with a zipper tape according to a
second exemplary embodiment.
[0028] FIG. 10 is a cross section showing engagement of a male
member and a female member of a packaging bag with a zipper tape
according to a third exemplary embodiment.
[0029] FIG. 11 is a cross section showing engagement of a male
member and a female member of a packaging bag with a zipper tape
according to a fourth exemplary embodiment.
[0030] FIG. 12 is a cross section showing engagement of a male
member and a female member of a packaging bag with a zipper tape
according to a fifth exemplary embodiment.
DESCRIPTION OF EMBODIMENT(S)
First Exemplary Embodiment
[0031] A packaging bag with a zipper tape according to a first
exemplary embodiment of the invention (hereinafter, occasionally
referred to simply as "a packaging bag") will be described with
reference to drawings.
[0032] The packaging bag of the invention is suitably filled with
liquids as contents. However, the packaging bag may be filled with
powders, solids or gel. Although a thick portion, a cut portion and
a seal base are exemplarily provided to a female member, the thick
portion, the cut portion and the seal base may be provided to a
male member.
Arrangement of Packaging Bag with Zipper Tape
[0033] As shown in FIGS. 1 and 2, a packaging bag 1 of this
exemplary embodiment includes a bag body 10 provided by laying base
films 11 (packing material) one on the other and forming side seal
bases 12 and a top seal base 13 on the periphery of the base films.
A zipper tape 20 includes a pair of a male member 21 and a female
member 22 including an engagement portion 23. The male member 21
includes a male belt-like portion 211. The female member 22
includes a female belt-like portion 221. The male belt-like portion
211 and the female belt-like portion 221 are continuously connected
to the engagement portion 23. The zipper tape 20 is attached to an
inner surface 10A of an opening portion 14 of the bag body 10. The
zipper tape 20 is sealed to the bag body 10 in a belt extending
from one of the side seal bases 12 to the other of the side seal
bases 12. The engagement portion 23 of the zipper tape 20 defines a
containing space 15 in the packaging bag 1.
[0034] In FIGS. 1 to 3, after the contents (not shown) are put
through a bottom of the bag body 10, the bottom side of the bag
body 10 is sealed, whereby the packaging bag 1 is hermetically
sealed.
[0035] In use, a user cuts the opening portion 14 to open the
packaging bag 1, and reseals the packaging bag with the zipper tape
20.
[0036] As shown in the cross section in FIG. 2, the zipper tape 20
includes the male member 21 provided on one side and the female
member 22 provided to the other side to engage with the male member
21, the male and female members 21 and 22 each formed of a
thermoplastic resin and having a belt-like shape.
[0037] The male member 21 includes: the male belt-like base 211
sealed to the bag body 10; a head 212 shaped substantially in an
arrowhead in cross section; and a connecting portion 213 for
connecting the male belt-like base 211 and the head 212. The male
belt-like base 211, the head 212 and the connecting portion 213 are
integrally formed.
[0038] Similarly to the male member 21, the female member 22
includes: the female belt-like base 221 sealed to the bag body 10;
and a first hook 222 and a second hook 223 that each have an
arcuate cross section and are connected to the female belt-like
base 221. The first hook 222 and the second hook 223 face each
other and are in a form of a groove detachably engageable with the
head 212 of the male member 21.
[0039] The male belt-like base 211 of the male member 21 includes:
a base facing surface 221A that is sealed to the inner surface 10A
in a manner to substantially face the inner surface 10A; and an
engagement-portion formation surface 221B near the engagement
portion 23 opposite to the base facing surface 221A. The female
belt-like base 221 of the female member 22 includes: a base facing
surface 221A that is sealed to the inner surface 10A in a manner to
substantially face the inner surface 10A; and an engagement-portion
formation surface 221B near the engagement portion 23 opposite to
the base facing surface 221A.
[0040] The engagement portion 23 of the zipper tape 20 is provided
by the head 212 of the male member 21 and the first and second
hooks 222, 223 of the female member 22. By engagement or
disengagement of the engagement portion 23, the packaging bag 1 is
sealed or opened.
[0041] As shown in FIGS. 2 and 3, the female belt-like base 221
integrally formed with the female member 22 includes a thick
portion 31, which is thicker than the female belt-like base 221, at
an end 224 of the bag body 10 near a containing space 15.
[0042] To an end of the thick portion 31 near the containing space
15, a belt-like cut portion 32, which is formed thinner than the
thick portion 31 and isolates the containing space 15 from the
outside, is connected.
[0043] To an end of the cut portion 32 near the containing space
15, a seal base 33, which is formed thicker than the female
belt-like base 221 and is sealed to the inner surface 10A, is
connected.
[0044] The thick portion 31 is formed thicker than the female
belt-like base 221 and projects from the engagement-portion
formation surface 221B while being formed in a belt from one side
seal base 12 to the other side seal base 12. The thick portion 31
is formed substantially in the same thickness as that of the seal
base 33.
[0045] A thickness of the thick portion 31 is preferably in a range
of 250 .mu.m to 550 .mu.m, more preferably in a range of 350 .mu.m
to 450 .mu.m. When the thickness of the thick portion 31 is less
than 250 .mu.m, a stress in opening the packaging bag 1 is
difficult to concentrate on the cut portion 32. On the other hand,
when the thickness of the thick portion 31 is more than 550 .mu.m,
it is difficult to form the side seal base 12.
[0046] The thick portion 31 is formed narrower toward the inner
surface 10A of the bag body 10, the inner surface 10A facing the
engagement-portion formation surface 221B. In other words, the
thick portion 31 is formed in a cross-sectionally trapezoidal
shape, in which a width of the thick portion 31 becomes narrower
toward its projecting end.
[0047] The thick portion 31 is sealed to the inner surface 10A
through an end surface 311 facing the inner surface 10A. Under such
a sealed situation, an end surface 312 of the thick portion 31, to
which the cut portion 32 is connected, is formed substantially
orthogonal to the inner surface 10A. Seal strength of the thick
portion 31 to the inner surface 10A is lower than that of the seal
base 33 to the inner surface 10A. The seal strength of the thick
portion 31 is adjusted by configuring the thick portion 31 to have
a seal area smaller than a seal area of the seal base 33 (a seal
area of an adhesion portion 331A later described) through a partial
seal portion 311A that is sealed in a dashed line in a longitudinal
direction (a horizontal direction in FIG. 1) of the cut portion
32.
[0048] The thick portion 31 is formed at a distance of 0.5 mm or
more between an outside edge of the end surface 311 and an end of
the male belt-like base 211 near the containing space 15. This is
because, if the distance is less than 0.5 mm, when the thick
portion 31 is sealed to the inner surface 10A, the thick portion 31
and the male belt-like base 211 may adhere to each other, so that a
favorable opening feeling may not be obtained or the bag cannot be
opened depending on the case. The thick portion 31 in a
cross-sectionally trapezoidal shape is formed to have an inclined
surface 313 such that the outer edge of the end surface 311 is
spaced away from the male belt-like base 211. Accordingly, the
thick portion 31 is prevented from adhering to the male belt-like
base 211 in sealing.
[0049] The cut portion 32 is formed in a belt extending from one of
the side seal bases 12 to the other of the side seal bases 12 and
in a direction orthogonal to the end surface 312 of the thick
portion 31 (a vertical direction in FIG. 3). The cut portion 32 is
formed to have a seal strength lower than that of the seal base 33
to the inner surface 10A. In other words, the cut portion 32 is
formed so as to be cut before the seal base 33 is peeled from the
inner surface 10A of the bag body 10. Specifically, a thickness of
the cut portion 32 is preferably in a range of 10 .mu.m to 80
.mu.m, more preferably in a range of 30 .mu.m to 60 .mu.m. When the
thickness of the cut portion 32 is less than 10 .mu.m, the cut
portion 32 may be cut by external pressure when the packaging bag 1
is dropped. On the other hand, when the thickness of the cut
portion 32 is more than 80 .mu.m, it may be difficult to cut the
cut portion 32 by hand. It should be noted that the strength of the
cut portion 32 may not be adjusted simply by setting the thickness
of the entire cut portion 32 in the above range. For instance, thin
portions may be formed in the cut portion 32 at every predetermined
distance between one of the side seal bases 12 and the other of the
side seal bases 12.
[0050] A width of the cut portion 32, i.e., a dimension in a
direction substantially orthogonal to a longitudinal direction of
the zipper tape 20 (i.e., the vertical direction in FIG. 3), is
preferably in a range of 0.3 mm to 1.5 mm, more preferably in a
range of 0.8 mm to 1.2 mm. If the width of the cut portion 32 is
less than 0.3 mm, when the zipper tape 20 is sealed to the bag body
10, it may be difficult to position the cut portion 32 so as not to
contact with the male belt-like base 211 of the male member 21 and
the inner surface 10A. On the other hand, when the width of the cut
portion 32 is more than 1.5 mm, the cut portion 32 may be stretched
in cutting to become difficult to cut.
[0051] The seal base 33 is formed in a belt having a
cross-sectionally rectangular shape extending from one of the side
seal bases 12 to the other of the side seal bases 12.
[0052] A seal surface 331 of the seal base 33 which is sealed to
the inner surface 10A is formed substantially flush with the end
surface 311 of the thick portion 31 which is sealed to the inner
surface 10A (see FIG. 6). The seal surface 331 includes the
adhesion portion 331A that is bonded to the inner surface 10A in a
comb-shape pattern. As shown in FIG. 1, the adhesion portion 331A
includes: a linear seal surface 331A1 that is linearly sealed along
the longitudinal direction (the horizontal direction in FIG. 1) of
the cut portion 32; and a plurality of end seal surfaces 331A2 that
are continuously formed with the linear seal surface 331A1, to
which an end surface 333 of the seal base 33 is sealed in a dashed
line. The linear seal surface 331A1 prevents leakage of the
contents and the plurality of end seal surfaces 331A2 allow the
stress to concentrate on the cut portion 32.
[0053] The end surface 333 of the seal base 33, to which the cut
portion 32 is connected, is formed substantially parallel to the
end surface 312 of the thick portion 31 facing the seal base 33 and
substantially orthogonal to the inner surface 10A of the bag body
10.
[0054] The male member 21 of the zipper tape 20 of the exemplary
embodiment can be integrally formed by co-extrusion, where the head
212 and the connecting portion 213 are continuously formed with the
male belt-like base 211. Similarly, the female member 22 can be
integrally formed by co-extrusion, where the first hook 222 and the
second hook 223 are continuously formed with the female belt-like
base 221. When the zipper tape 20 is formed by such co-extrusion,
the zipper tape 20 can be manufactured in a simplified process at
low costs, and can be stably manufactured in a continuous
manner.
[0055] The male member 21 and the female member 22 of the zipper
tape 20 may be formed of polyethylene and polypropylene and are
preferably formed of extension-resistant polypropylene.
Specifically, thermoplastic resins such as homo-polypropylene,
block-polypropylene, random polypropylene (RPP),
propylene-ethylene-butene-1 random terpolymer and polyolefin-based
special flexible resins, and a mixture thereof are usable.
[0056] When random polypropylene (RPP) is used as the resin forming
zipper tape 20, a melt flow rate (MFR) of RPP is preferably from
0.5 to 20 g/10 min, particularly preferably from 1 to 15 g/10
min.
[0057] When the MFR of random polypropylene is less than 0.5 g/10
min, co-extrusion moldability of the engagement portion 23, which
is formed continuously and integrally with the male belt-like base
211 and the female belt-like base 221, may be deteriorated. On the
other hand, the MFR exceeding 20 g/10 min may cause ends of the
first and second hooks 222 and 223 of the female member 22 to be
likely closed or may cause the connecting portion 213 of the male
member 21 to be likely tilted down, which may make it difficult to
extrude the zipper tape 20 into a predetermined
reopenable/resealable shape.
[0058] By sealing the zipper tape 20 to the base film 11 of the bag
body 10 and forming the base film 11 into a bag, the packaging bag
1 as shown in FIG. 1 can be obtained.
[0059] While the base film 11 (packaging material) for forming the
bag body 10 is preferably a layered film in which a sealant layer
111 is layered onto a base layer 112, the base film 11 may be a
layered film in which a layered film layer (not shown) including
layers of a gas barrier layer, a light-shielding layer and a
strength-reinforcing layer is provided as a middle layer between
the base layer 112 and the sealant layer 111, depending on a
required performance.
[0060] Examples of the material for the base layer 112 are
preferably a biaxially-oriented polypropylene film (OPP film), a
biaxially-oriented polyester film such as biaxially-oriented
polyethylene terephthalate film (PET film) and biaxially-oriented
polyethylene naphthalate film and a biaxially-oriented polyamide
film such as nylon 6, nylon 66 and MXD6 (poly-meta-xylylene
adipamide). Depending on needs, various engineering plastic films
are also usable. One of the above may be used alone, or a
combination of two or more of the above may be layered in use.
[0061] When the middle layer is a gas barrier layer, examples of
the usable material for the middle layer are a film of saponified
ethylene-vinyl acetate copolymer (EVOH) or polyacrylonitrile (PAN),
aluminum foil, a deposited layer of silica, alumina or aluminum and
a coating layer of PVDC.
[0062] When a deposited layer of silica, alumina or aluminum or a
coating layer of PVDC is used, such a layer may be deposited or
coated on the inner surface 10A of the bag body 10 of the base
layer 112. Alternatively, such a layer may be preliminarily
deposited or coated on another biaxially-oriented nylon film (ONy
film), biaxially-oriented polyethylene terephthalate film (PET
film) or biaxially-oriented polypropylene film (OPP film), and the
film may be layered on the middle layer.
[0063] Among the above, aluminum foil and a deposited layer of
aluminum, which are opaque, can also serve as a light-shielding
layer.
[0064] The layering of the base layer 112 and the film of the
intermediate layer can be conducted by a known dry lamination
method or extrusion lamination method (sandwich lamination
method).
[0065] For the sealant layer 111 (the innermost layer),
polypropylene (CPP) and the like are usable.
[0066] In order to layer the sealant layer 111, the above resins
may be formed into film and layered by a dry lamination method or
extrusion lamination method. Alternatively, the above resins may be
layered thereon by extrusion coating.
[0067] The packaging bag 1 according to this exemplary embodiment
can be easily manufactured with use of, for instance, a bag-making
machine for three-sided sealing and attaching a zipper tape.
[0068] Sealing conditions (temperature, pressure, etc.) in the
manufacturing can be properly determined in accordance with types
of the resins for forming the zipper tape 20 and the base film 11
for forming the bag body 10.
[0069] Opening Operation of Packaging Bag with Zipper Tape
[0070] Next, description will be made with reference to FIGS. 2, 4
and 5 on how the packaging bag 1 according to this exemplary
embodiment is opened.
[0071] FIG. 2 shows engagement of the male member 21 and the female
member 22 of the zipper tape 20. In this engagement, at a lower
side of the engagement portion 23 (i.e., near the containing space
15) in FIG. 2, the adhesion portion 331A of the seal base 33 is
sealed to the inner surface 10A of the bag body 10. This
arrangement can maintain air-tightness and water-tightness of the
bag, and liquid contents can be kept from infiltrating into a gap
in the engagement portion 23 of the zipper tape 20, for instance,
during transportation.
[0072] Next, when the contents are to be taken out from the
packaging bag 1, as shown in FIG. 4, the opening portion 14 is cut
to open the zipper tape 20, thereby disengaging the engagement of
the engagement portion 23. By further opening an upper side (a side
opposite to the containing space 15) of the bag body 10, the thick
portion 31 is peeled from the inner surface 10A of the bag body 10
by such an opening force, as shown in FIG. 5. By the opening force
to further open the upper side of the bag body 10, stretching force
acts on the cut portion 32. At this time, since the end surface 333
of the seal base 33 near the cut portion 32 is kept orthogonal to
the inner surface 10A of the bag body 10 by the end seal surfaces
331A2 of the adhesion portion 331A, the end surface 333 of the seal
base 33 does not become loose from the inner surface 10A, so that
the stretching force efficiently acts on the cut portion 32. The
cut portion 32 is cut by the stretching force, so that the thick
portion 31 is separated from the seal base 33. Thus, the contents
can be taken out from the inside of the packaging bag 1.
[0073] Manufacturing Instrument of Packaging Bag with Zipper
Tape
[0074] Next, a manufacturing instrument of the packaging bag with
the zipper tape according to the first exemplary embodiment will be
described with reference to FIGS. 6 to 8.
[0075] The manufacturing instrument used for manufacturing the
packaging bag 1 includes a bag-making section. FIG. 6 shows how the
contents are sealed in a substantial part of the bag-making
section.
[0076] In FIG. 6, the bag-making section includes: a tape adhesion
section (not shown) that positions the zipper tape 20 fed from a
tape feeder (not shown) between a pair of the base films 11 fed
from a packaging material feeder (not shown) and heat-seals the
zipper tape 20 to both of the base films 11; and a seal section
that seals and weld-cuts the delivered base films 11 at a
predetermined distance in a delivering direction of the base films
11, i.e., at a distance corresponding to a dimension in a width
direction of the packaging bag 1, thereby forming the packaging bag
1.
[0077] The seal section includes a pair of seal bars 60 that are
disposed to face each other with interposing the packaging bag 1
that is filled with contents P while the zipper tape 20 is
fastened.
[0078] The seal bars 60 are mutually approachable and separable.
When the seal bars 60 are separated from each other, the packaging
bag 1 containing the contents P is held at a predetermined
position. At this time, when the seal bars 60 approach each other,
one of the seal bars 60 presses the seal base 33 via the base film
11, thereby forming the adhesion portion 331A on the seal base
33.
[0079] As shown in FIG. 7, the one of the seal bars 60 is provided
with pressing protrusions 60A in the same continuous comb-shape as
that of the adhesion portion 331A. As shown in FIG. 8, the adhesion
portion 331A of the seal base 33 is formed to have a predetermined
width in the width direction of the bag body 10 and a comb-shape
dented at a predetermined distance in the longitudinal direction of
the bag body 10. The adhesion portion 331A is sealed with the seal
bars 60 in such a manner that ends of the pressing protrusions 60A
reach the thick portion 31 across the cut portion 32.
[0080] In this exemplary embodiment, when the zipper tape 20 near
the containing space 15 is sealed, the adhesion portion 331A is
formable by using the seal bars 60 provided with the pressing
protrusions 60A having the same shape as the adhesion portion 331A.
Thus, it is possible to manufacture the packaging bag 1 in which
the thick portion 31 is easily peelable and the cut portion 32 is
easily cuttable by the force applied for opening the zipper tape
20.
Advantages of First Exemplary Embodiment
[0081] With the above-described packaging bag 1, the following
advantages can be attained.
[0082] Specifically, in the first exemplary embodiment, the thick
portion 31 is formed thick at the end 224 of the female belt-like
base 221 near the containing space 15. To the thick portion 31 near
the containing space 15, the cut portion 32 thinner than the female
belt-like base 221 is provided. To the cut portion 32 near the
containing space 15, the seal base 33, which is thicker than the
female belt-like base 221 and is sealed to the inner surface 10A of
the bag body 10 to which the male belt-like base 211 is attached,
is provided. The thick portion 31 is attached to the inner surface
10A to which the male belt-like base 211 is attached by the seal
strength lower than that of the seal base 33. The cut portion 32 is
formed to have strength lower than the seal strength of the seal
base 33 and to be spaced away from the inner surface 10A of the bag
body 10 and separate the containing space 15 from the outside in a
form of a belt.
[0083] With this arrangement, an area surrounded by the thick
portion 31, the cut portion 32, the seal base 33 and the inner
surface 10A of the bag body 10 becomes substantially hermetically
sealed. Accordingly, even if external pressure or internal pressure
of the bag is applied on the bag body 10 to which the zipper tape
20 is attached and which contains the contents P in the containing
space 15, the substantially hermetically sealed area works as a
buffer area of the pressure applied on a surface of the cut portion
32 near the containing space 15. With this arrangement, even if the
cut portion 32 is set to have a predetermined strength enough to be
easily cut in opening, the cut portion 32 is prevented from being
stretched by external pressure or internal pressure of the bag to
be broken on next impact, or the cut portion 32 is prevented from
occasionally having pinholes to damage sealability for separating
the containing space 15 from the outside, particularly
water-tightness. Consequently, according to this exemplary
embodiment, it is avoidable to damage openability by forming the
cut portion 32 thick for improving sealability, thereby providing
both a favorable openability and a sufficient sealability.
[0084] Moreover, in the first exemplary embodiment, the thick
portion 31 and the seal base 33 are formed substantially in the
same thickness.
[0085] With this arrangement, when the seal bars 60 heat-weld the
thick portion 31 and the seal base 33, the seal bars 60 come into
contact with the thick portion 31 and the seal base 33
substantially at the same time, whereby a predetermined pressure is
applied on the end surface 311 of the thick portion 31 and the seal
surface 331 of the seal base 33, so that the end surface 311 and
the seal surface 331 can be bonded under a predetermined
heat-welding condition.
[0086] In other words, if one of the end surface 311 and the seal
surface 331 is formed thicker than the other, the seal bars 60 need
to be pressed harder in order to seal the other, so that the cut
portion 32 may be damaged by heat. If the thick portion 31 is
formed thinner and is not appropriately sealed on the bag body 10,
the cut portion 32 may be stretched to damage sealability when
external pressure is applied on the bag body 10. On the other hand,
if the thick portion 31 is formed thicker, the seal strength is
increased to require a large force for peeling the thick portion 31
from the bag body 10 in opening, so that an opening feeling may be
impaired. If the seal bars 60 are formed corresponding to different
thicknesses for solving such disadvantages, a shape of the seal
bars 60 becomes complicated to increase instrument costs and
positioning of the seal bars 60 in sealing also becomes
complicated, so that the manufacturing efficiency of the packaging
bag 1 may not be improved.
[0087] For solving such disadvantages, according to the above
arrangement of this exemplary embodiment, an arrangement in which
the thick portion 31 is sealable by the seal strength lower than
that of the seal base 33 is provided by a simple arrangement in
which the thick portion 31 and the seal base 33 are formed
substantially in the same thickness.
[0088] Moreover, in the first exemplary embodiment, the thick
portion 31 is formed in a cross-sectionally trapezoidal shape, in
which a width of the thick portion 31 becomes narrower toward the
inner surface 10A of the bag body 10.
[0089] With this arrangement, in sheet-sealing, a seal depth is
easily adjustable, which makes it possible to set the seal
conditions in a broad range.
[0090] For instance, when the thick portion 31 is formed in a
cross-sectionally inverse trapezoidal shape in which the width of
the thick portion 31 becomes wider toward the end surface 311 and
the inclined surface 313 is inversely inclined, it is difficult to
stably mold the thick portion 31 to hinder improvement in
productivity. Particularly, in a cross-sectionally inverse
trapezoidal shape in which the end surface 312 of the thick portion
31 approaches the seal base 33 toward the end surface 311, resins
flowed out in sealing may be bonded to the cut portion 32 or the
seal base 33, so that an opening feeling may be impaired.
[0091] In view of the above, according to the above arrangement of
this exemplary embodiment, an arrangement to provide a favorable
opening feeling can easily be manufactured by co-extrusion.
[0092] The cut portion 32 is formed in a belt extending in a
direction orthogonal to the end surface 312 of the thick portion 31
(in the vertical direction in FIG. 3).
[0093] Accordingly, even when external pressure is applied on the
bag body 10, the external pressure is substantially evenly applied
on the entire cut portion 32, so that the cut portion 32 can be
kept from being stretched by partially receiving a high pressure,
and decrease in water-tightness caused by generation of pinholes
can be prevented.
[0094] Further, the surfaces of the thick portion 31 and the seal
base 33 to be sealed on the inner surface 10A of the bag body 10
are formed substantially flush with each other. The seal base 33 is
designed to have a higher seal strength higher than the thick
portion 31.
[0095] Examples of methods to achieve the above arrangement
include: sealing the thick portion 31 and the seal base 33 from an
outer surface of the bag body 10 using comb-shaped heat seal bars
60; forming the thick portion 31 using a non-compatible resin with
the resin used in the sealant layer 111 of the bag body 10; and
setting a melting point of the resin used for the thick portion 31
higher than a melting point of the resin used for the seal base 33.
By using these methods, such design that the seal base 33 is sealed
by the seal strength higher than that of the thick portion 31 is
reliably obtained, thereby easily providing an arrangement with a
favorable openability and a sufficient water-tightness.
Second Exemplary Embodiment
[0096] Next, a second exemplary embodiment of the invention will be
described with reference to the drawings.
[0097] FIG. 9 is an enlarged perspective view showing a vicinity of
a seal base of a zipper tape of a packaging bag according to the
second exemplary embodiment of the invention. It should be noted
that, in the second exemplary embodiment, description of an
arrangement that is the same as or similar to the arrangement of
the first exemplary embodiment is omitted or simplified.
[0098] A thick portion 41 of the second exemplary embodiment is
provided by forming the thick portion 31 of the first exemplary
embodiment into a cross-sectionally rectangular shape. The thick
portion 41 includes two ribs 411 having a cross-sectionally
triangular shape along a longitudinal direction of the cut portion
32 on a surface of the thick portion 41 facing the inner surface
10A of the bag body 10 to which the male belt-like base 211 is
attached. The ribs 411 are preferably formed to have a
predetermined height. Specifically, when the height is less than 5
.mu.m, the rib is sealed up to an end surface of a base thereof,
which means that formation of the ribs 411 is not necessary. When
the height is more than 300 .mu.m, it is difficult to form the side
seal bases 12 in the packaging bag 1.
[0099] A thickness of the thick portion 41, which is defined as a
dimension from a bottom surface continuous to the female belt-like
base 221 to a tip end of the rib 411, is formed substantially the
same as that of the seal base 33.
[0100] In the second exemplary embodiment, the seal base 33 is
bonded to the bag body 10 with an arrangement in which the linear
seal surface 331A1 and the end seal surface 331A2 of the adhesion
portion 331A in the first exemplary embodiment are separated.
[0101] According to the second exemplary embodiment, since the ribs
411 to be bonded to the bag body 10 are provided, the seal strength
is reduced because of decrease in seal area on the bag body 10, so
that a large force is not required in opening and a favorable
opening feeling can be provided. Particularly, even when the thick
portion 41 needs to be bonded to the bag body 10 all along the
longitudinal direction of the cut portion 32 in order to more
reliably prevent the cut portion 32 from being damaged by external
pressure, the thick portion 41 can easily be bonded to the bag body
10 by a seal strength lower than that of the seal base 33 and a
favorable opening can be provided.
[0102] Moreover, even by the method of bonding the linear seal
surface 331A1 and the end seal surface 331A2 in the separate
arrangement in the second exemplary embodiment, similarly to the
first exemplary embodiment, the stress appropriately concentrates
on the cut portion 32 in opening, whereby the cut portion 32 can be
cut and a favorable opening feeling can be provided,
[0103] In the second exemplary embodiment, the ribs 411 are not
limited to two ribs, but may be provided by a single rib or plural
ribs. A shape of each of the ribs 411 is not only linear, but may
be wavy or in a dashed line. The adhesion portion 331A of the seal
base 33 may be bonded by any bonding method such as one in a
comb-shape pattern of the first exemplary embodiment.
Third Exemplary Embodiment
[0104] Next, a third exemplary embodiment of the invention will be
described with reference to the drawings.
[0105] FIG. 10 is a cross-sectional view showing engagement of a
male member and a female member of a zipper tape in a packaging bag
according to a third exemplary embodiment of the invention. Also in
the third exemplary embodiment, description of an arrangement that
is the same as or similar to the arrangement of the above exemplary
embodiments is omitted or simplified.
[0106] According to the third exemplary embodiment, a cut portion
42 is provided by forming the cut portion 32 of the second
exemplary embodiment in a plane on which the cut portion 42
intersects with the inner surface 10A of the bag body 10 facing the
thick portion 41 and the seal base 33. In case external pressure is
applied, in order to prevent pressure concentration, it is
preferable to provide a curved surface 421 formed in a
cross-sectionally arc at an acute connecting point between the cut
portion 42 and the seal base 33.
[0107] Also with this arrangement, similar to the second exemplary
embodiment, a favorable opening feeling can be provided in opening
and a favorable sealability can be obtained without causing such
damage as the cut portion 42 is stretched even when external
pressure is applied.
[0108] In the third exemplary embodiment, a direction in which the
plane of the cut portion 42 is inclined is not limited to the above
arrangement, but may be an inverse direction. The cut portion 42
may be curved.
Fourth Exemplary Embodiment
[0109] Next, a fourth exemplary embodiment of the invention will be
described with reference to the drawings.
[0110] FIG. 11 is a cross-sectional view showing engagement of a
male member and a female member of a zipper tape in a packaging bag
according to a fourth exemplary embodiment of the invention. Also
in the fourth exemplary embodiment, description of an arrangement
that is the same as or similar to the arrangement of the above
exemplary embodiments is omitted or simplified.
[0111] According to the fourth exemplary embodiment, a cut portion
52 is provided by forming the cut portion 42 of the second
exemplary embodiment thicker toward the thick portion 41.
[0112] With this arrangement, a position where the cut portion 52
is cut is a connecting point (the thinnest point) between the cut
portion 52 and the seal base 33, so that the products can be cut at
the same cut position and the opening feeling can be kept
constant.
Fifth Exemplary Embodiment
[0113] Next, a fifth exemplary embodiment of the invention will be
described with reference to the drawings.
[0114] FIG. 12 is a cross-sectional view showing engagement of a
male member and a female member of a zipper tape in a packaging bag
according to a fifth exemplary embodiment of the invention. Also in
the fifth exemplary embodiment, description of an arrangement that
is the same as or similar to the arrangement of the above exemplary
embodiments is omitted or simplified.
[0115] In the fifth exemplary embodiment, the female belt-like base
221 of the female member 22 in the first exemplary embodiment
includes an adhesion base 24 at an end near the opening portion 14.
The female belt-like base 221 of the female member 22 is bonded to
the inner surface 10A of the bag body 10 near the male member 21
with the engagement-portion formation surface 211B via the adhesion
base 24. An opening tape 40 is attached between the adhesion base
24 and the male belt-like base 211 of the male member 21.
[0116] The base facing surface 221A opposite to the
engagement-portion formation surface 211B is spaced away from the
inner surface 10A of the bag body 10 at a predetermined distance.
In other words, the female belt-like base 221 of the female member
22 is not sealed to the inner surface 10A of the bag body 10.
[0117] With this arrangement, the base facing surface 221A is
spaced away from the inner surface 10A of the bag body 10 at a
predetermined distance. Accordingly, the containing space 15 is
enlarged, i.e., a so-called dead space is decreased, so that the
packaging bag 1 can contain larger amount of contents. Moreover,
the internal pressure of the packaging bag 1 is less likely to be
applied on the cut portion 32, so that damage (e.g., the stretch)
to the cut portion 32 can be prevented even when an external force
(e.g., impact on the bag body 10 when dropped) is applied.
Modification
[0118] The scope of the invention is not limited to the
above-described embodiments but also includes modifications and
improvements as long as an object of the invention can be
achieved.
[0119] The pair of seal bars 60 that are positioned to face each
other with the packaging bag 1 interposed therebetween are used for
heat-welding the thick portion 31, 41 and the seal base 33, but an
arrangement of the seal bars 60 is not limited to this. For
instance, only a single seal bar may be provided on one side of the
packaging bag 1, or plural seal bars may be provided on one side of
the packaging bag 1.
[0120] The adhesion method for the thick portion 31, 41 and the
seal base 33 is not limited to the heat-welding method. Various
methods such as an adhesion method using an adhesive or the like
are applicable.
[0121] Other specific arrangements and shapes for carrying out the
invention may be altered as long as an object of the invention is
achieved.
EXAMPLES
[0122] The invention will further be described below with reference
to examples and a comparative example. It should be noted that the
invention is not limited to the contents of the examples and the
like.
Example 1
[0123] With use of random polypropylene having MFR of 7 and a
melting point of 140 degrees C., the zipper tape shaped as shown in
FIG. 2 was manufactured under the following conditions.
Arrangement of Zipper Tape
[0124] Thickness of Thick Portion: 300 .mu.m
[0125] Thickness of Cut Portion: 50 .mu.m
[0126] Width of Cut Portion: 0.5 mm
[0127] Thickness of Seal Base: 400 .mu.m
[0128] Arrangement of Bag Body
[0129] The base film forming the bag body, which was a film
provided by dry-laminating the biaxially-oriented polyester film
(thickness: 12 .mu.m), the biaxially-oriented nylon film
(thickness: 15 .mu.m) and a cast polypropylene film (60 .mu.m), was
used for manufacturing a bag shown in FIG. 1.
[0130] As shown in FIG. 8, the seal base was sealed at a 1-mm width
in the width direction of the bag (the direction orthogonal to the
longitudinal direction of the zipper tape) and was sealed by the
comb-shaped seal bar having a 1-mm width and 10-mm intervals in the
longitudinal direction of the zipper tape in such a manner that
ends of the comb reached the thick portion 31 across the cut
portion 32.
[0131] An inner size of the bag from the seal of the seal base to
the bottom of the containing space was set to be a width of 180 mm
and a depth of 200 mm.
Example 2
[0132] A packaging bag was manufactured in the same manner as that
in Example 1 except that the dimensions of the portions of the
zipper tape in Example 1 were replaced by the following.
[0133] Thickness of Thick Portion: 500 .mu.m
[0134] Thickness of Cut Portion: 50 .mu.m
[0135] Width of Cut Portion: 0.5 mm
[0136] Thickness of Seal Base: 400 .mu.m
Example 3
[0137] A packaging bag was manufactured in the same manner as that
in Example 1 except that the dimensions of the portions of the
zipper tape in Example 1 were replaced by the following.
[0138] Thickness of Thick Portion: 400 .mu.m
[0139] Thickness of Cut Portion: 50 .mu.m
[0140] Width of Cut Portion: 0.5 mm
[0141] Thickness of Seal Base: 400 .mu.m
Comparative 1
[0142] With use of random polypropylene having MFR of 7 and a
melting point of 140 degrees C., in the same shape as that of the
zipper tape disclosed in JP-A-2008-24324 (FIG. 4), a zipper tape
was manufactured under the following conditions.
[0143] JP-A-2008-24324 (FIG. 4) discloses:
[0144] Thickness of Male Belt-like Base (reference numeral 321 in
FIG. 4) of Male Member and Female Belt-like Base (reference numeral
331 in FIG. 4) of Female Member: 150 .mu.m
[0145] Seal Base (reference numeral 36): 150 .mu.m
[0146] Thickness of Cut Portion (Linear Portion: reference numeral
35): 40 .mu.m
[0147] Width of Cut Portion: 0.1 mm
[0148] The base film, which was a film provided by dry-laminating a
biaxially-oriented polyester film (12 .mu.m), a biaxially-oriented
nylon film (15 .mu.m) and a cast polypropylene film (60 .mu.m), was
used for manufacturing the bag shown in FIG. 2, similarly to
Example 1.
[0149] Similarly to Example 1, as shown in FIG. 8, the seal base
was sealed at a 1-mm width in the width direction of the bag and
was sealed by the comb-shaped seal bar having a 1-mm width and
10-mm intervals in the longitudinal direction in such a manner that
ends of the comb reached the belt-like base across the cut
portion.
[0150] An inner size of the bag from the seal of the seal base to
the bottom of the containing space was set to be a width of 180 mm
and a depth of 200 mm.
Evaluation
[0151] The packaging bags manufactured in Examples 1 to 3 and
Comparative 1 were evaluated according to the following method. The
evaluation results are shown in Table 1.
Evaluation Method
[0152] (1) The cut portion was opened by hand.
[0153] A: easily openable
[0154] B: resistant to be opened, but openable
[0155] C: difficult to be opened
(2) Water of 400 ml was filled in the manufactured bag and the bag
was sealed. The bag was dropped by N10 from a height of 1.2 m. It
was checked whether the cut portion was cut. This procedure was
carried out on 50 bags in total.
[0156] A: No cut
[0157] B: Cut in one or two bags
[0158] C: Cut in three bags or more
(3) Total Evaluation
[0159] A: A for all of the items
[0160] B: one of B and the others of A
[0161] C: one or more of C
TABLE-US-00001 TABLE 1 Opening Dropped-Bag Total Feeling Breakage
Resistance Evaluation Example 1 A B B Example 2 B A B Example 3 A A
A Comparative 1 C B C
INDUSTRIAL APPLICABILITY
[0162] The invention is applicable as a packaging bag for packaging
various articles such as foods, pharmaceutical and medical
products, cosmetics and groceries.
EXPLANATION OF CODES
[0163] 1: packaging bag with a zipper tape [0164] 10: bag body
[0165] 10A: inner surface [0166] 14: opening portion [0167] 15:
containing space [0168] 20: zipper tape [0169] 21: male member
[0170] 211: male belt-like base [0171] 22: female member [0172]
221: female belt-like base [0173] 23: engagement portion [0174] 31,
41: thick portion [0175] 32,42,52: cut portion [0176] 33: seal
base
* * * * *