U.S. patent application number 10/525003 was filed with the patent office on 2005-10-27 for gusset bag and method of producing the same.
Invention is credited to Ikeda, Kazuhiro, Shimizu, Takashi.
Application Number | 20050238264 10/525003 |
Document ID | / |
Family ID | 31943861 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050238264 |
Kind Code |
A1 |
Ikeda, Kazuhiro ; et
al. |
October 27, 2005 |
Gusset bag and method of producing the same
Abstract
A gusset bag having side films folded inwardly and an opening
portion at the upper edge of the bag, said gusset bag further
having a reinforcing resin layer at least on the side edge.
Inventors: |
Ikeda, Kazuhiro; (Chuo-ku,
JP) ; Shimizu, Takashi; (Chuo-ku, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
31943861 |
Appl. No.: |
10/525003 |
Filed: |
February 17, 2005 |
PCT Filed: |
August 14, 2003 |
PCT NO: |
PCT/JP03/10341 |
Current U.S.
Class: |
383/120 ;
383/104; 383/107; 383/119; 383/906 |
Current CPC
Class: |
B65D 75/008 20130101;
B65D 75/52 20130101; B65D 75/5883 20130101 |
Class at
Publication: |
383/120 ;
383/119; 383/906; 383/104; 383/107 |
International
Class: |
B65D 030/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 2002 |
JP |
2002-239556 |
Claims
1. A gusset bag having side films folded inwardly and an opening
portion at the upper edge of the bag, said gusset bag further
having a reinforcing resin layer at least on the side edge.
2. The gusset bag of claim 1 wherein the reinforcing resin layer is
further provided on the upper edge.
3. The gusset bag of claim 2 wherein a spout is provided at the
opening portion with bonding to the reinforcing resin layer.
4. The gusset bag of claim 3 wherein the reinforcing resin layer
and the spout are integrally molded.
5. A method for producing a gusset bag having side films folded
inwardly and an opening portion at the upper edge of the bag
comprising: injecting a resin to the side edge of the gusset bag or
the side edge and the upper edge of the gusset bag to form a
reinforcing resin layer.
6. The method of producing the gusset bag of claim 5 wherein the
spout is formed at the opening portion and the reinforcing resin
layer is formed integrally with the spout by injecting the resin.
Description
TECHNICAL FIELD
[0001] The present invention relates to a gusset bag having
flexibility and at the same time good self-standing property and
also having high bonding strength of,a spout, and a method of
producing such a gusset bag.
BACKGROUND ART
[0002] Among conventional packaging containers (bags) for filling
liquids or the like, there is known a gusset bag made of a flexible
packaging material which is mainly composed of a plastic film.
[0003] The conventional gusset bags, however, have the
disadvantages that the self-standing property is gradually injured
as the content filled therein is decreased and the upper part
thereof is bent down, thereby losing the self-standing property.
Especially, the gusset bags for filling liquids usually have a
spout for flowing out the content. In that case, the upper part of
the gusset bag is heavy, and it is clear that the gusset bag tends
to lose the self-standing property as the content is getting
decreased. The usual method for producing a gusset bag having a
spout comprises preparing a bag body by fusion bonding the
predetermined parts of the peripheral edges of sheets,
independently molding a spout, manually inserting the spout between
the sheets forming the bag body and fusion bonding the spout with
the inner faces of the sheets to attach the spout to the bag body.
Such manual operation is unfavorable to mass production, and is
insufficient in fusion bonding between the spout and the sheets,
resulting in insufficient bonding strength thereof. On the other
hand, molded containers have rightfully a sufficient self-standing
property. However, it is unable to fold the containers into a
smaller size when discarded.
DISCLOSURE OF THE INVENTION
[0004] The present invention has been completed in view of the
above circumstances. It is an object of the present invention to
provide a gusset bag which retains its self-standing property until
the content filled therein is completely consumed, is capable of
folding into a small size when discarded, and has a high attachment
strength of a spout, and also to provide a method for producing
such a gusset bag.
[0005] The present invention provides the following gusset bag and
method of producing the gusset bag in order to attain the above
object.
[0006] [I] A gusset bag having side films folded inwardly and an
opening portion at the upper edge of the bag, said gusset bag
further having a reinforcing resin layer at least on the side
edge.
[0007] [II] The gusset bag of [I] wherein the reinforcing resin
layer is further provided on the upper edge.
[0008] [III] The gusset bag of [II] wherein a spout is provided at
the opening portion with bonding to the reinforcing resin
layer.
[0009] [IV] The gusset bag of [III] wherein the reinforcing resin
layer and the spout are integrally molded.
[0010] [V] A method for producing a gusset bag having side films
folded inwardly and an opening portion at the upper edge of the bag
comprising:
[0011] injecting a resin-to the side edge of the gusset bag or the
side edge and the upper edge of the gusset bag to form a
reinforcing resin layer.
[0012] [VI] The method of producing the gusset bag of [V] wherein
the spout is formed at the opening portion and the reinforcing
resin layer is formed integrally with the spout by injecting the
resin.
[0013] In the gusset bag of the present invention, the reinforcing
resin layer, especially one on the side edge, constitutes a
so-called rib of the bag body and functions as a support of the
bag, thereby improving the self-standing property of the bag body
and retaining its sufficient self-standing property until the
content is completely discharged even in the case where the bag is
provided with a spout. In the case where the spout is integrally
molded with the above-described resin layers, the bag has an
excellent attachment strength of the spout.
[0014] The reinforcing resin layer on the side edge will exert its
reinforcing effect so long as it is formed at least at one of four
side edges, although it is effective to form the layer preferably
at two side edges, more preferably at all the four side edges.
Moreover, the reinforcing resin layer may be formed on at least
part of one side edge, although the layer can be formed along the
entire length of one side edge from the upper end to the lower
end.
[0015] The reinforcing resin layer may be formed on any portion of
the side edge including a ridgeline, an inside part of the folded
gusset (a side film site), a front surface site or a rear surface
site. In case that the layer is formed only on the front surface
site and/or the rear surface site, the gusset bag is easy to fold
and the reinforcing resin layer is easy to form. Especially, it is
preferable that the reinforcing resin layer extends over from the
side edge portion, which will spread when content is filled, to the
upper edge, since the gusset bag is easy to unfold.
[0016] The spout is used as a nozzle especially when the content of
the gusset bag is a liquid. It is preferable that the spout is
integrally molded with the reinforcing resin layer from the
viewpoint of retaining the self-standing property of the gusset bag
and the attachment strength of the spout.
[0017] The spout may be integrally molded simultaneously with
molding the reinforcing resin layer. The spout previously molded
may be integrated with the reinforcing resin layer by in-mold
molding when the layer is molded. In this case, the spout is
preferably bonded with the reinforcing resin layer.
[0018] The gusset bag of the present invention should desirably be
produced by forming the bag body in the conventional procedure and
then the reinforcing resin layer on the upper edge or the side edge
of the bag-body should be formed. But, even if the upper edge or
the side edge is not bonded or the side edge is bonded with so
slight bonding strength that the bag body manages to keep its shape
when the bag body is formed, it is preferable that the reinforcing
resin layer is formed so as to cover the upper edge or the side
edge, thereby enabling to strengthen the bonding strength and to
bond the side edge of the bag body firmly.
BRIEF DESCRIPTION OF THE DRAWING
[0019] FIG. 1 is a schematic perspective view illustrating the
structure of the gusset bag according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0020] One embodiment of the present invention will be described
with reference to the accompanying drawing. FIG. 1 shows a gusset
bag body having a rectangular bottom part 2, a front surface part
3, a rear surface part 4, and two side films 5 and 6. Both the side
films are provided so that they are able to fold inwardly. In the
state that both the side films 5 and 6 are folded inwardly, the
bottom part 2 may be formed as a style of a square bottom bag which
can be folded toward the rear surface part 4.
[0021] The upper edge 7 of the bag body 1 is formed by superposing
the upper edges of the front and rear surface parts 3 and 4 each
other and bonding them so that an opening portion is formed at the
center of the upper edge thereof. To the opening portion is
attached a spout 9.
[0022] The reinforcing resin layer 10 is formed on the upper edge 7
of the bag body 1 and on only the front surface site 3 and the rear
surface site 4 of each side edge. In the illustrated embodiment,
the reinforcing resin layer 10 formed on each side edge extends to
the vicinity of the lower end of each side edge. The reinforcing
resin layer should desirably be formed such that they extend at
least from the upper portion, preferably at least the upper end
portion of each side edge to the middle of the side edge along with
each edge line. Needless to say, the reinforcing resin layer may
extend over the entire length of each side edge.
[0023] In the illustrated embodiment, the spout 9 is integrally
bonded to the opening portion 8 using the same resin when the
reinforcing resin layer 10 is formed.
[0024] Each film constituting the bag body 1 is properly selected
according to the method for bonding the films each other and the
adhesion properties with the resin layer upon producing the gusset
bag of the present invention, and the kind of content to be filled
in the gusset bag. When the films are fusion bonded each other upon
producing the gusset bag of the present invention, the film should
desirably have heat bonding ability. In addition, the film face
constituting the outer surface of the gusset bag when the bag is
produced should desirably have good adhesion properties with the
resin for forming the reinforcing resin layer 10.
[0025] The above-mentioned film may be a monolayer film or a
multilayer film. Examples of the multilayer films include
co-extruded films and laminate films. The monolayer film or the
multilayer film may be composed of an oriented or non-oriented
polyolefin, nylon, or polyester film or the like. EVOH film,
vinylidene chloride film, and ceramics-deposited film etc. are also
desirable as gas barrier material. The film is not limited to a
plastic film but it includes paper or metal foil (e.g. aluminum
foil etc.) in monolayer film or laminate film. It is desirable to
use a monolayer plastic film, multilayer plastic film, or plastic
laminate film having a different kind of materials such as metal
deposited layer, metal foil, and paper.
[0026] The film may have a thickness ranging from 20 to 900 .mu.m.
A thick film is desirable for self-standing property, but a thin
film is desirable for flexibility and light weight. Even a bag of
thin film can exhibit the self-standing property if it is provided
with the reinforcing resin layer. A preferable thickness is 60 to
200 .mu.m from the standpoint of moldability and handling
property.
[0027] The spout 9 is not specifically restricted in size and
shape. It may have any size and shape suitable for the purpose of
use as a packaging bag. The conventional self-standing bag provided
with a spout is produced by inserting the spout in the opening
portion of the bag body manually or automatically with an inserting
machine as an additional operation, and heat bonding. A big spout
often makes it difficult to bond firmly the both sides of the end
of the spout and to carry out the fusion boding operation. On the
other hand, such difficulties would not be brought in the present
invention, since a thick spout can be integrally bonded with the
reinforcing resin layer 10 or integrally molded with the
reinforcing resin layer 10.
[0028] The material of the spout 9 is not specifically restricted.
It may be properly selected according to the content to be filled
in the gusset bag, bonding ability with the reinforcing resin layer
10, the self-standing property of the gusset bag and so on.
Examples of the spout materials include general-purpose resins such
as polyethylenes and polypropylenes, engineering resins such as
nylons and polyesters, and elastomers. They may be used alone or in
combination with one another in the form of copolymer or blend.
[0029] The reinforcing resin layer 10 may be formed from any
material identical with or different from that of the spout 9. Such
materials are desirable which have properties of injection molding
and bonding with the edge of the bag body 1. Examples of materials
of the reinforcing resin layer include general-purpose resins such
as polyethylenes and polypropylenes, engineering resins such as
nylons and polyesters, elastomer-blended resins, and copolymer
resins.
[0030] The reinforcing resin layer 10 is not specifically
restricted in width and thickness. If it is formed on the side edge
in a such shape that is tapered off toward its end (toward the
bottom of the bag), then it should desirably have a width ranging
from 1 to 20 mm, particularly 5 to 10 mm, and a thickness ranging
from 1 to 10 mm, particularly 2 to 5 mm measured at the part of the
uniform width. In the case where almost all the reinforcing resin
layer is formed uniform shape, the average width and average
thickness should preferably be within the above-mentioned range.
With an excessively small width or thickness, the reinforcing resin
layer will be difficult to bond to the bag body 1 with a sufficient
attachment strength. With an excessively large width or thickness,
it is feared that the reinforcing resin layer needs more resin than
that is necessary being undesirable for waste, and prevents the
gusset bag from easy opening, and reduces the sufficient volume of
the bag.
[0031] In the case where the reinforcing resin layer on the side
edge is formed such that the lower part of the side edge remains
uncovered by the reinforcing resin layer 10, the length of the
reinforcing resin layer should preferably be 60% or above,
particularly 80% or above, of the entire length of the side edge.
In this case, if the length of the uncovered part is equal to the
sum of the width of the folded side film and the width of the
bottom seal, the reinforcing resin layer 10 formed in this manner
reaches the surface on which the bag is placed when the gusset bag
is intended to stand. In addition, the reinforcing resin layer 10
formed in this manner does not exist at the bottom 2. So, these
help the bag to stand stably.
[0032] The gusset bag body 1 may be produced by any known method.
The reinforcing resin layer 10 on the upper edge 7 and side edges
of the bag body may be formed by bonding a strip-shaped resin layer
previously molded with an adhesive or by heat sealing, or by
injecting resin to the upper edge 7 and each side edge. In this
case, when the spout 9 is formed at the opening portion 8, it is
preferable to mold the spout 9 to the opening portion 9 by
injecting the same resin simultaneously with the injection molding
of the reinforcing resin layer. Alternatively, it is also possible
to mold the spout in advance and then integrally bond the spout
with the reinforcing resin layer 10 upon forming the layer by
injecting molten resin to the bag body 1 in a mold.
[0033] The gusset bag of the present invention has an excellent
self-standing property although it is flexible. It functions as a
packaging bag having self-standing performance and retains its
self-standing property until the content therein is completely
consumed even though it is provided with spout. After use, it can
be folded in a small volume to discard. Moreover, the gusset bag of
the present invention has a high attachment strength of the spout.
In addition, the reinforcing resin layer can strengthen the bonding
strength of the bag. Accordingly, the gusset bag of the present
invention is easy to use, has a high strength as a packaging bag,
and is easy to reduce its volume upon discarding the bag after use.
Thus it is suitable for environmental protection. According to the
method of producing the gusset bag of the present invention, the
gusset bag having the above-described properties and an excellent
strength as a packaging bag can be manufactured with ease and
reliability. Moreover, the present invention permits production of
various gusset bags having self-standing properties suitable for
any content by selecting the material for the bag body, the type of
the molded spout, and the type of the resin properly. The gusset
bags of the present invention can be used as a substitution for
bottles and cans.
* * * * *