U.S. patent application number 10/500049 was filed with the patent office on 2005-03-10 for self-standing bag and method of manufacturing the bag.
Invention is credited to Ikeda, Kazuhiro, Katsuhara, Takaaki, Usami, Yoshimi.
Application Number | 20050053314 10/500049 |
Document ID | / |
Family ID | 19189544 |
Filed Date | 2005-03-10 |
United States Patent
Application |
20050053314 |
Kind Code |
A1 |
Ikeda, Kazuhiro ; et
al. |
March 10, 2005 |
Self-standing bag and method of manufacturing the bag
Abstract
A self-standing bag (1) having a spout (3) on a bag body (2),
characterized in that both side edges (2a, 2a) and an upper edge
(2b) of the bag body (2) are sealed by an edge sealer (4) of
thermoplastic resin covering the outer surfaces of the edges, and
the spout (3) is formed integrally with the edge sealer (4).
Inventors: |
Ikeda, Kazuhiro; (Tokyo,
JP) ; Usami, Yoshimi; (Tokyo, JP) ; Katsuhara,
Takaaki; (Hiroshima-shi Hiroshima, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
19189544 |
Appl. No.: |
10/500049 |
Filed: |
August 5, 2004 |
PCT Filed: |
December 26, 2002 |
PCT NO: |
PCT/JP02/13587 |
Current U.S.
Class: |
383/104 ;
383/107; 383/906 |
Current CPC
Class: |
B29L 2031/7128 20130101;
B65D 75/008 20130101; B29L 2031/7158 20130101; B29C 45/14475
20130101; B65D 75/5866 20130101 |
Class at
Publication: |
383/104 ;
383/906; 383/107 |
International
Class: |
B65D 030/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2001 |
JP |
2001-399960 |
Claims
1. A self-standing bag having a spout at an upper portion of a bag
body, characterized in that both side edges and an upper edge of
said bag body are sealed by an edge sealer made of thermoplastic
resin which covers the outer surfaces of said edges, and said edge
sealer is integrally molded with said spout.
2. The self-standing bag as set forth in claim 1, wherein said edge
sealer of said bag body and said spout are formed by injection
molding.
3. The method of manufacturing a self-standing bag as set forth in
claim 1, characterized in that, in case of forming said edge sealer
of said bag body, cavities are formed in a mold at the places
corresponding to said edges of said bag body, and then a
thermoplastic resin is injected into the cavities to seal said
edges of said bag body, thereby forming said edge sealer.
4. The method of manufacturing a self-standing bag as set forth in
claim 1, characterized in that, in case of forming said edge sealer
of said bag body, a die slide injection system is used in which one
cavity in the shape of a half part of said edge sealer is formed in
the mold at the place corresponding to one surface of said edges of
said bag body, and a thermoplastic resin is injected into said
cavity to mold a half part of said edge sealer, then another cavity
in the shape of the remainder part of said edge sealer is formed in
the mold at the place corresponding to the other surface of said
edges of said bag body, and a thermoplastic resin is injected into
said cavity to mold the remainder part of said edge sealer to seal
said edges of said bag body, thereby forming said edge sealer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a self-standing bag having
a spout, and more particularly to a self-standing bag that is
flexible and has good self-standing performance and high fixing
strength of the spout.
BACKGROUND ART
[0002] Conventionally, self-standing bags for fluids in which a
liquid is filled have been used mainly for refilling use, and
little attention has been paid-to the self-standing performance.
Therefore, when the amount of the content has been decreased, for
example, to 1/3 or less of the initial amount, the conventional
self-standing bag loses its self-standing function because of
bending at the upper portion of the bag. Particularly, a
self-standing bag for a fluid may have a spout for pouring the
content. In such a case, the upper portion of the bag becomes heavy
and the self-standing performance may be considerably injured. In
addition, the conventional self-standing bag having a spout has
been formed by a method in which peripheral edges of a bag body are
sealed by fusion bonding, the spout is separately molded, and the
molded spout is manually inserted between sheets constituting the
bag body to fusion bond to the inner surfaces of the sheets,
thereby attaching the spout to the bag. Such a manual operation not
only affects the mass-productivity, but also renders the fusion
bonding between the spout and the sheets unsatisfactory, resulting
in an insufficient strength of the bag body. On the other hand,
molded vessels naturally have a sufficient self-standing
performance, but they cannot be reduced in size by folding at the
time of disposal.
DISCLOSURE OF INVENTION
[0003] The present invention has been made under the above
circumstances. Accordingly, it is an object of the present
invention to provide a self-standing bag which maintains the
self-standing performance until the content is used up, can be
reduced in volume by folding in case of disposing of the bag, and
has a high fixing strength of a spout, and a method of
manufacturing such a self-standing bag.
[0004] According to the present invention, there is provided a
self-standing bag having a spout at an upper portion of a bag body,
characterized in that both side edges and an upper edge of the bag
body are sealed by an edge sealer made of thermoplastic resin which
covers the outer surfaces of said edges, and the edge sealer is
integrally molded with the spout. In this case, it is more
preferable that the edge sealer of the bag body and the spout are
formed by injection molding.
[0005] According to the present invention, there is also provided a
method of manufacturing the above-mentioned self-standing bag,
characterized in that, in case of forming the edge sealer of the
bag body, a cavity is formed in a mold at the places corresponding
to the edges of the bag body, and then a thermoplastic resin is
injected into the cavity to seal the edges of the bag body, thereby
forming the edge sealer. In this case, it is more preferable that,
in case of forming the edge sealer of the bag body, a die slide
injection system is used in which one cavity in the shape of a half
part of the edge sealer is formed in the mold at the place
corresponding to one surface of the edges of the bag body, a
thermoplastic resin is injected into the cavity to mold the half
part of the edge sealer, then another cavity in the shape of the
remainder part of the edge sealer is formed in the mold at the
place corresponding to the other surface of the edges of the bag
body, and a thermoplastic resin is injected into the cavity to mold
the remainder part of the edge sealer to seal the edges of the bag
body, thereby forming the edge sealer.
[0006] The self-standing bag according to the present invention has
a structure in which the upper edge and both the side edges of the
bag body are sealed by the edge sealer made of a thermoplastic
resin which covers the outer surfaces of the edges. Therefore, the
edge sealer at the respective edges can constitute ribs of the bag
body to function as support of the bag, thereby enhancing the
self-standing performance of the bag body. A sufficient
self-standing performance can be maintained until the contents are
consumed completely, although the spout is provided at the upper
portion of the self-standing bag. Since the spout is integrally
molded with the edge sealer, the fixing strength of the spout to
the bag is excellent.
[0007] It is more preferable that the edge sealer of the bag body
and the spout are formed by injection molding, because it is
possible to form the edge sealer and to simultaneously perform
integral molding of the spout easily and securely by, for example,
the die slide injection system.
[0008] The method of manufacturing the self-standing bag according
to the present invention is characterized in that, in case of
forming the edge sealer of the bag body, cavities are formed in a
mold at the places corresponding to the edges of the bag body, and
a thermoplastic resin is injected into the cavities to seal the
edges of the bag body, thereby forming the edge sealer. In the
manufacturing method, for example, in case of forming the edge
sealer of the bag body of the self-standing bag, a die slide
injection system is used in which one cavity in the shape of a half
of the edge sealer is formed in the mold at the place corresponding
to one surface of the edges of the bag body, a thermoplastic resin
is injected into the cavity to mold a half part of the edge sealer,
then another cavity in the shape of the remainder part is formed in
the mold at the place corresponding to the other surface, and a
thermoplastic resin is injected into the cavity to mold the
remainder part of the edge sealer to seal the edges of the bag
body, thereby forming the edge sealer. According to such a method,
it is possible to arrange the edges of the bag body securely at the
center of the resin (the center of the edge sealer) and to seal the
edges of the bag body more easily and securely, in case of covering
the outer surfaces of the edges of the bag body with the
thermoplastic resin, as compared with the case of conducting, for
example, one-stage injection molding for forming the edge sealer by
injecting the thermoplastic resin so as to cover the outer surfaces
of the edges of the bag body disposed in a mold in the condition
where sheets overlap on each other.
[0009] The self-standing bag according to the present invention is
flexible and has good self-standing performance, so that the bag
functions as a self-standing packing bag and fulfills the
self-standing performance until the contents are completely
consumed upon use in spite that the spout is attached, and the bag
can be disposed by rolling up the bag with a reduction in volume
after the completion of use. Further, the self-standing bag is high
in fixing strength of the spout to the bag. Therefore, the
self-standing bag according to the present invention is easy to
use, and is easy to reduce in volume in case of disposing of the
bag after the completion of use, which is suited to environmental
protection. According to the method of manufacturing a
self-standing bag of the present invention, the self-standing bag
having the above-mentioned characteristics and particularly having
an excellent seal strength of the bag body can be manufactured
easily and securely.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a schematic perspective view of a self-standing
bag for illustrating an embodiment of configuration of the
self-standing bag according to the present invention.
[0011] FIG. 2 is a schematic front view of the self-standing
bag.
[0012] FIG. 3 is a schematic diagram showing an injection mold for
illustrating an embodiment of the method of manufacturing a
self-standing bag according to the present invention.
[0013] FIG. 4 is a schematic diagram showing the injection
mold.
[0014] FIG. 5 is a schematic partial view of the injection
mold.
[0015] FIG. 6 is another schematic partial view of the injection
mold.
BEST MODE FOR CARRYING OUT THE INVENTION
[0016] The present invention will be described more in detail
below, referring to the drawings. FIG. 1 and FIG. 2 illustrate one
embodiment of configuration of the self-standing bag according to
the present invention, in which FIG. 1 is a schematic perspective
view showing the condition where the self-standing bag 1 is
expanded, and FIG. 2 is a schematic front view showing the
condition where the self-standing bag 1 is folded. The
self-standing bag 1 has a spout 3 at an upper edge of a bag body 2,
a long film constituting the bag body 2 is piled by folding the
film in four at the lower portion thereof, and one side edge 2a,
the upper edge 2b, and the other side edge 2a of the folded film
are sealed as described later, whereby a bottom portion 2c is
formed.
[0017] The bag body 2 is formed from a monolayer or multilayer
film. These films may not necessarily have a fusion-bondability,
which has been required for the conventional films. It is
preferable, however, that the film surface which is to become an
outer surface of a bag has a good adhesion with a resin to be
injected for forming an edge sealer. The multilayer film is a
co-extruded film, a laminate film, or the like. An oriented or
unoriented polyolefin, nylon, polyester film, or a film for
imparting required functions to the resin layer including a
co-extrusion type film with a gas barrier layer (EVOH, saran,
ceramic vapor deposition, etc.) or a laminate type film thereof is
suitably used.
[0018] The thickness of the film is 20 to 900 .mu.m. From the
viewpoint of self-standing property, a thick film is suitable. From
the viewpoint of flexibility and light-weightness, a thin film is
used. Even a thin film can secure the self-standing property by
forming the edge sealer. In view of moldability and handleability,
the film thickness is preferably 100 to 200 .mu.m. The film is not
limited to those made of synthetic resin, and may be a monolayer or
laminate film of paper or metal foil.
[0019] The spout 3 is not particularly limited as to shape and size
thereof. The spout 3 can have arbitrary shape and size according to
the purpose of use of the packing bag. Generally, a self-standing
bag with a spout is manufactured by inserting the spout into the
upper edge of the self-standing bag by a separate operation using
hands or an automatic inserting machine, followed by fusion
bonding. Therefore, when the thickness of the spout is large, it is
difficult to adhere tightly in the both side of the spout to the
bag, and the fusion operation involves difficulties in many cases.
On the other hand, in the present invention, such difficulties are
obviated because the spout is injection molded integrally with the
edge sealer 4, as will be described later.
[0020] The edge sealer 4 is simultaneously and integrally molded
with the spout 3 by injection molding, or is integrally molded in a
mold with a preliminarily molded spout 3. The resins for forming
these parts are not particularly limited, inasmuch as they can be
injection molded and can seal the edges of the bag body 2. Examples
of the resins utilized include not only polyethylene and
polypropylene reins, which are general-purpose resins, but also
injectable plastics, for example, blends or copolymer of nylon,
polyester, various engineering resins, elastomers, etc.
[0021] The edge sealer 4 are so shaped as to conform to the one
side edge 2a, the upper edge 2b, and the other side edge 2a of the
bag body 2 composed of the resin film preliminarily formed into the
shape of a predetermined self-standing bag. The edge sealer 4 is
not particularly limited as to width and thickness. It is
preferable, however, that the width (arrow w in FIG. 1) is 1 to 20
mm, particularly 5 to 10 mm, and the thickness (arrow d in FIG. 1)
is 1 to 10 mm, particularly 2 to 5 mm. Where the width is too small
or the thickness is too small, it may be impossible to obtain a
sufficient seal strength. Where the thickness is too large, the
amount of resin used is increased, which is unfavorable from the
viewpoint of disposal properties. Where the width is too large, it
may be difficult for the self-standing bag to have a sufficient
internal volume.
[0022] The method of manufacturing the self-standing bag 1 is not
particularly limited. It is preferable to manufacture the
self-standing bag 1 by using an injection molding machine A capable
of in-mold molding and insert molding. As shown in FIGS. 3 and 4,
the machine A includes a first mold 5 for forming between an upper
half mold 5a and a lower half mold 5b a cavity for forming a half
part of the edge sealer on one surface of the edges of a bag body
and forming the spout at a predetermined position of the upper edge
of the bag body, and a second mold 6 for forming between an upper
half mold 6a and a lower half mold 6b a cavity for forming the
remainder part of the edge sealer on the other surface of the edges
of the bag body, in which the upper half molds 5a and 6a are
provided respectively with injection ports 7, 7, and which is of
the die slide injection system having such a structure that the
first mold 5 and the second mold 6 are slidable. By using a resin
film 2' which is preliminarily formed and folded so as to have a
predetermined self-standing bag shape, the bag can be prepared as
follows.
[0023] First, as shown in FIG. 3, the resin film 2' is set on the
lower half mold 5b of the first mold 5, then the upper half mold 5a
is moved downwardly, and a tapered tip end 8a of a slide core 8 for
forming the spout is inserted between the films at one end part 2'a
for constituting the upper edge of the bag body, while the part
folded in four of the other end part 2'b for forming the bottom
portion of the bag body is set to be piled as if the bottom portion
becomes one sheet. After such a setting, a resin is injected to the
peripheral edges except the end edge of the bottom portion, whereby
the expandable bottom portion is formed. Specifically, with the
upper half mold 5a moved downwardly, a cavity 9a in the shape of a
half part of the edge sealer is formed in the lower half mold at
the places corresponding to the upper peripheral edge and the side
peripheral edges of the bag body, as shown in FIG. 5, fronting on
the one end part 2'a and the both side edges (not shown) of the
resin film 2'. Then, by use of the injection port 7 provided in the
upper half mold 5a, an ejection mechanism (not shown) provided in
the lower half mold 5b, and a vacuum drawing mechanism connected to
the cavity, a molten thermoplastic resin is injected into the
cavity of the first mold 5 to mold the spout at a location to
become a predetermined position of the upper edge of the bag body,
and simultaneously to achieve primary molding of the half part 4a
of the edge sealer on one surface of the portions corresponding to
the upper edge and the both side edges of the bag body, as shown in
FIG. 5. Next, the second mold 6 is slid, and the thermoplastic
resin is similarly injected into the cavity 9b of the second mold 6
as shown in FIG. 6, to achieve secondary molding of the remainder
part 4b of the edge sealer on the other surface of the
above-mentioned portions and to seal the portions corresponding to
the upper edge and the both edges of the bag body, thereby forming
the edge sealer 4 and manufacturing the self-standing bag.
[0024] When the edge sealer 4 is formed in two stages as described
above, the sealing can be achieved in the condition where the edges
of the resin film 2' are clamped between the central portion of the
edge sealer, while obviating the problem that the overlapping edges
of the resin film 2' so folded as to have a bag body shape would be
opened by the thermoplastic resin injected into the cavity and the
problem that the film edges would be distorted in one direction in
the overlapping state.
[0025] The self-standing bag is preserved and transported, after
the contents (not shown) are charged into the bag through the
spout, the bag is set into a self-standing shape with the bottom
portion expanded and the spout is sealed. Upon use, the contents
can be discharged from the bag through the spout. The kind of the
contents is not particularly limited, but a fluid material is
preferred as the contents. For example, liquids, viscous materials,
powders, small-diameter particles and the like can be preferably
contained in the bag. Since the edge sealer at the both side edges
function as ribs, the self-standing bag can maintain the
self-standing property until the contents thereof are consumed
completely, and can be reduced in volume by rolling up at the time
of disposal.
[0026] Incidentally, the present invention is not limited to the
above-described constitution, and various modifications are
permitted without departure from the gist of the invention.
[0027] For example, according to such conditions as the flexibility
of the film and the moldability of the resin, the molding may be
carried out in one stage. In place of sliding the mold as mentioned
above, a system may be adopted in which slidable pins are provided
in the mold, injection is conducted to an intermediate stage in the
condition where the edges of the bag body are clamped by the pins
so as to be located at the center of the edge sealer, then the pins
are retracted by sliding, the remainder of resin is injected to
fill up the void portions where the pins have been present, thereby
molding the edge sealer in a predetermined thickness to seal the
edges of the bag body, followed by fixation.
[0028] As to the spout, a variety of selections can be made. For
example, a cap to be sealed by a screw or a cap capable of being
opened and closed with a hinge may be used, and a spout provided
with a nozzle for taking out the contents by suction may be
used.
[0029] Furthermore, as to the shape of the bag body, a variety of
deformed bag designs may be adopted, inasmuch as the self-standing
function through the spreading of the bottom is not spoiled.
* * * * *