JP7409469B2 - How to design free-standing packaging bags - Google Patents

Description

The present invention relates to a self-supporting packaging bag, and particularly to a technique suitable for use in preventing bag breakage due to drop impact.

Sealant layers of two laminated films, each having at least a base layer and a sealant layer, are used as refill containers for various liquids, such as liquid detergents, kitchen detergents, fabric softeners, deodorants, etc. Standing pouches are made by placing two bags facing each other, inserting a bottom tape folded in half so that the sealant layer is on the outside, and sealing the edges. It is widely used for this reason.

One of the problems with such self-supporting packaging bags is that when a drop test is performed with the bag filled with liquid, the bag tends to break at certain parts. Particularly, the part where the bag is easily torn is the part where the folded part of the bottom tape that is folded in two intersects with the side seal part.

This part has three seal parts: a front side bottom seal part that seals the front side laminated film and bottom tape, a back side bottom seal part that seals the back side laminated film and bottom tape, and a side seal part. This is the part where they intersect.
As a measure to improve the strength against bag breakage, the shape of the bottom seal line, especially the shape near the intersection (seal intersection) where the above three seal parts intersect, has a large influence.

For this reason, in Prior Patent Document 1, in the bottom seal line consisting of a straight line extending from the seal intersection point, a circular arc on the bottom surface, and a line smoothly connecting them, the angle between the straight line extending from the seal intersection point and the bottom tape folding line is The aim is to improve strength by showing that strength changes and keeping it within a certain suitable range.

Further, Patent Document 2 describes a bottom seal portion in which the shape of the bottom seal portion near the seal intersection point where the three seal portions intersect is concave.

Patent No. 6079091 Japanese Patent Application Publication No. 2003-128082

When filled with liquid, the shape of the bottom of the self-supporting packaging bag is determined by the shape and width of the curved line (bottom seal line) at the boundary between the bottom tape and the main laminated film adhesive section, and the height of the bottom tape-unsealed portion.
However, when the bottom seal line near the intersection is a straight line as in Patent Document 1, the bottom surface cannot fully expand into the designed shape due to the balance between the internal pressure due to the weight of the liquid filled and the rigidity of the film itself. , distortion may occur.
When such distortion occurs, the internal pressure increases due to the impact of the drop, causing the distorted area to spread rapidly, causing stress to concentrate at both ends (particularly at the intersection of the seals), which is one of the causes of bag breakage. There was a problem.

The present invention has been made in view of the above-mentioned circumstances, and is intended to achieve the object of improving bag breakage resistance in a self-supporting packaging bag (standing pouch).

As a result of intensive studies to solve the above problems, the inventors of the present application found that it is preferable to uniformly distribute the force over the entire seal boundary line that seals the bottom tape and the laminated film on the front and back surfaces of the main body. For this purpose, it has been found that the shape of the bottom seal line may be set so as to make it possible to achieve a state in which no distortion occurs or a state in which distortion is reduced on the bottom surface.

One example of the shape of many conventionally adopted bottom seal lines is that the central part is represented by a circular arc with a certain radius, and the circular arc and a straight line extending from the intersection of the seals at both ends toward the center are in contact with each other. A shape in which points are smoothly connected is described in patent documents.

However, in order to prevent distortion of the bottom surface of a packaging bag with such a bottom seal line shape when the contents are stored and opened three-dimensionally, it is necessary to seal the main body at the intersection of the seals at both ends. The laminated film on the front and back sides must be bent linearly. However, since the laminated film on the front and back surfaces of the main body itself has rigidity, even if internal pressure is applied to open the packaging bag, the laminated film on the front and back surfaces of the main body will open in a smooth curved shape from the seal intersection. It has been found that the cause of distortion in the bottom surface is that the bottom shape of the container cannot be opened completely and an excess portion is generated.

Therefore, in order to prevent the occurrence of distortion, it is necessary to consider a shape that allows the laminated films on the front and back surfaces of the main body near the seal intersection to open smoothly. Therefore, in order to suppress the distortion of the bottom surface that occurs when filling contents such as liquid, the shape of the bottom seal line near the seal intersection should be changed to a curve in which the laminated films on the front and back surfaces of the main body open toward the center at this point. The present invention was completed based on the idea that it would be effective to create equivalent curves.

In the present invention, the sealant layers of a front laminated film and a back laminated film each having a base material layer and a sealant layer are made to face each other, and a bottom tape having a base material layer and a sealant layer is placed between them, with the sealant layer facing outward. This is a design method for a self-supporting packaging bag that is folded in half and inserted, and the opposing sealant layers are sealed together.
In this method, the boundary line between the inner edge of the bottom sealed part and the unsealed part, which is the area where the front laminated film and the bottom tape and the back laminated film and the bottom tape are sealed , is defined as the bottom seal line. The boundary line between the inner edge of the side seal part, which is the part where the back layered film is sealed, and the unsealed part is defined as the side seal line,
A temporary packaging bag formed using the surface laminated film, the back laminated film, and the bottom tape and having the same external dimensions as the self-supporting packaging bag before filling is filled with liquid to the extent that the bottom tape is sufficiently expanded. to establish filling status,
Measure the outer circumferential shape of the temporary packaging bag excluding the side seal portion at the height of the seal intersection when the temporary packaging bag is viewed from above in the filled state,
The bottom seal line of the self-supporting packaging bag is a convex curve in which the vicinity of the seal intersection is upwardly convex, and the radius of curvature R of this convex curve is the left and right width dimension between the seal intersections in the temporary packaging bag before filling with contents. W, the left and right width dimension between the seal intersections in the temporarily manufactured packaging bag in the filled state is W2, and the radius of curvature near the seal intersection in the outer circumferential shape is R2,
(W/W2)×R2≧R>R2
Set to satisfy.

The self-supporting packaging bag according to the present invention has improved tear resistance.

FIG. 1 is a perspective view showing a first embodiment of a self-supporting packaging bag according to the present invention. FIG. 1 is an exploded perspective view showing a first embodiment of a self-supporting packaging bag according to the present invention. FIG. 2 is a schematic front view showing a bottom seal line in the first embodiment of the self-supporting packaging bag according to the present invention in a folded state without filling with contents. FIG. 2 is an enlarged perspective view showing the state of filling the bottom surface of the first embodiment of the self-supporting packaging bag according to the present invention. FIG. 2 is a schematic plan view showing the outer peripheral contour of the first embodiment of the self-supporting packaging bag according to the present invention in a filled state. It is an explanatory view showing the relationship between the planar state of the bottom seal line and the filling state in the first embodiment of the self-supporting packaging bag according to the present invention. FIG. 2 is an explanatory diagram showing a calculation method for calculating a bottom seal line in the first embodiment of the self-supporting packaging bag according to the present invention. FIG. 2 is a perspective view for explaining a comparison of the amount of distortion of the bottom surface in the first embodiment of the self-supporting packaging bag according to the present invention. FIG. 2 is an enlarged front view showing the vicinity of the seal intersection in the first embodiment of the self-supporting packaging bag according to the present invention.

Hereinafter, a first embodiment of a self-supporting packaging bag according to the present invention will be described based on the drawings.
FIG. 1 is a perspective view showing a self-supporting packaging bag according to the present embodiment, and FIG. 2 is an exploded perspective view showing the self-supporting packaging bag according to the present embodiment. In the figures, reference numeral 10 indicates the self-supporting packaging bag.

A self-supporting packaging bag (standing pouch) 10 according to the present embodiment is used as a refill container for liquid detergent, kitchen detergent, fabric softener, deodorant, etc., and is filled with liquid as shown in FIG. The storage is made up of a substantially rectangular front laminated film 11, a back laminated film 12, and a bottom tape 13, which are sealed on three sides by side seal parts 14, 14 and a bottom seal part 16, and filled with contents. A filling portion 17 is formed, and the upper portion is sealed after filling.

When the self-supporting packaging bag (standing pouch) 10 is in a standing position, the surface laminated film 11 is located on the front side in the front-rear direction (Y direction), the back laminated film 12 is located on the rear side in the front-rear direction (Y direction), and the bottom tape 13 is located at the bottom.
The surface laminated film 11, the back laminated film 12, and the bottom tape 13 are all laminates having a base material layer and a sealant layer, and the front laminated film 11 and the back laminated film 12 have their sealant layers facing each other. Then, the bottom tape 13 is folded downward in half so that the sealant layer is on the outside and inserted between them, and the opposing sealant layers are sealed together.

The bottom tape 13 is arranged so that the ridge line 15, which is the folding line when the self-supporting packaging bag 10 is folded in half, is in a substantially horizontal direction in a folded state in which the self-supporting packaging bag 10 is not filled with contents.

The parts to be sealed include side seal parts 14, 14 that seal the front and back laminated films 11, 12 at the side positions of the container, and a bottom seal part 16 that seals the main laminated films 11, 12 and the bottom tape 13 at the lower part of the container. is provided.

The side seal parts 14 , 14 are provided with substantially uniform widths at both end positions in the left-right direction (X direction) of the self-supporting packaging bag 10 over substantially the entire length in the up-down direction (Z direction), and have a substantially uniform width. is sealed.
The side seal portions 14, 14 are formed in a substantially linear shape extending in the vertical direction (Z direction).

In the side seal portion 14, when the boundary line between the inner edge and the unsealed portion that becomes the filling portion 17 is defined as a side seal line 24, the side seal line 24 is formed to be a straight line. Note that the side seal line 24 only needs to be formed in a straight line at least in the portion connected to the bottom seal portion 16, and the upper side of the self-supporting packaging bag 10 is not limited to this shape.

The bottom seal part 16 is for sealing the front laminated film 11 and the bottom tape 13 or the back laminated film 12 and the bottom tape 13, and its lower side has a semicircular shape made of a generally downwardly convex curve. has been done.
On the lower side, which is the center position of the bottom seal part 16, there is an unsealed part which becomes a filling part 17 having a generally semicircular or boat shape at the upper position.

In the bottom seal portion 16, when the boundary line between the inner edge and the unsealed portion that becomes the filling portion 17 is defined as the bottom seal line 26, both ends of the bottom seal line 26 in the left and right direction (X direction) are the seal intersection points 18, 18. It is connected to the side seal line 24 at.

FIG. 3 is a schematic front view showing the bottom seal line in a folded state without filling with contents.
A dimension W in the left-right direction (X direction) between the seal intersection points 18 and 18 is set equal to a dimension W in the left-right direction (X direction) between the side seal portions 14 and the side seal portions 14 .
The bottom seal line 26 has a symmetrical shape in the left-right direction (X direction), and is set so that the center position that is lowest from the seal intersection point 18 has a depth dimension D1.

The bottom seal line 26 is formed by connecting a convex curve 26Cx that is convex upward near the seal intersection 18 position, a concave curve 26Cb that is convex downward at the center of the bottom, and two straight lines 26Lb. ing. As will be described later, the convex curve 26Cx has a radius of curvature R, and the concave curve 26Cb at the center of the bottom has a radius of curvature larger than that.

Both ends of the folded bottom tape 13 in the left and right direction (X direction), which are inside, may be adhered to each other. In this case, the front laminated film 11 and the back laminated film 12 can be sealed by providing cutouts from both sides of the bottom tape 13 or by providing through holes in the bottom tape 13. .

Here, the notch or the through hole can have a size corresponding to the horizontal dimension of the side seal part 14, and can have the same horizontal dimension as the side seal part 14, for example. Note that the bonding of both inner sides of the bottom tape 13 is not limited to this configuration, and the inner side surfaces of the bottom tape 13 may also be bonded.

FIG. 4 is a partially enlarged perspective view showing the self-supporting packaging bag according to the present embodiment, in which the contents are filled and the expanded bottom surface is formed.
When the self-supporting packaging bag 10 sealed in a bag shape is filled with liquid, the unsealed part of the bottom tape 13 spreads as shown in FIG. The entire body bulges out along line 36 and becomes self-supporting. In addition, in FIG. 4, since the swollen self-supporting packaging bag 10 has a symmetrical shape in the X direction and the Y direction, only one quarter thereof is shown.

FIG. 5 is a schematic plan view showing the outer peripheral contour of the self-supporting packaging bag according to the present embodiment in a state where the bag is filled with contents and expanded.
When the self-supporting packaging bag 10 of this embodiment is viewed from directly above during liquid filling, as shown in FIG. 21 and 22, which extend in the front-rear direction (Y direction).

This radius of curvature R2 varies depending on the weight of the liquid to be filled, the size of the self-supporting packaging bag 10, etc., as well as differences in rigidity due to the layer structure, material, and film thickness of the front and back laminated films 11 and 12 forming the main body. However, the higher the rigidity and hardness of the film, the larger it becomes.

The outer peripheral contours 21 and 22 during liquid filling are set to have a dimension D2 from a center line 25 connecting the seal intersection points 18 and 18 in the Y direction, as shown in FIG. At the same time, corresponding to the fact that the outer peripheral contours 21 and 22 have expanded by the dimension D2, the X-direction dimension W2 between the seal intersection points 18 and the seal intersection points 18 during liquid filling is changed to the unfilled dimension as shown in FIG. It is smaller than W.

The shape of the conventional bottom seal line 126 shown by the broken line in FIG. 3 is a shape in which a straight line 126La extending from the seal intersection point 18 and a curved line 126Ca in the center are smoothly connected, but in a bulged state as shown in FIG. Then, when the unsealed portion of the bottom tape 13 becomes the bottom surface 20, the straight line 126La near the seal intersection 18 cannot be opened sufficiently, and the bottom surface is distorted due to the surplus portion.

In this way, if a drop impact is applied to the bottom surface with distortion, the unopened distorted portion will rapidly expand due to the increase in internal pressure caused by the drop impact. As a result, pressure is concentrated near the seal intersection 18, which tends to cause the bag to break.

Therefore, if there is no distortion in the bottom surface 20, the entire bottom seal line 36 can receive the pressure increase due to the drop impact, and the pressure is dispersed, which relieves pressure concentration near the seal intersection 18 and causes the bag to break. Considering this, the shape of the bottom seal line 26 before filling was set so that the bottom surface 20 would not be distorted when the liquid was filled.

Here, the deformation of the bottom surface 20 before and after liquid filling in an ideal state will be explained.

When the self-supporting packaging bag (standing pouch) 10 formed by the bottom seal line 26 shown in FIG. 3 is filled with liquid, it swells into the shape shown in FIG. 4 to form the bottom surface 20. At this time, the bottom seal line 26 transforms into a three-dimensional bottom seal line 36. Since the bottom seal line 26 and the bottom seal line 36 are the same line, their lengths are the same.

In addition, the bottom center line 35 is the same as the bottom seal line 36 viewed from the front side (front side) in the Y direction, and the outer peripheral contours 21 and 22 at the time of filling are the same as the bottom seal line 36 from directly above the bottom seal line 36 downward in the Z direction. It will look the same as it looks.

Furthermore, the depth dimension D1 of the bottom seal portion 16 and the dimension D2 in FIG. 5 have the same value. In other words, the bottom center line 35 and the outer circumferential shapes 21 and 22 at the time of filling are the same shape except for a 90° difference in direction.

Next, the relationship between the bottom seal line 26 before filling and the bottom seal line 36 after liquid filling in the self-supporting packaging bag 10 of this embodiment will be described based on FIG. 6.

FIG. 6 is an explanatory diagram showing the relationship between the planar state of the bottom seal line and the filled state in the self-supporting packaging bag according to the present embodiment.
The coordinates of any two points on the bottom seal line 36 during liquid filling are
Point a (x1, y1, z1)
Point b (x2, y2, z2)
The coordinates of the two points corresponding to point a and point b in the plane state before filling are
Point c (x3, y3, z3)
Point d (x4, y4, z4)
shall be.

The length Lab of the curve between points a and b is equal to the length Lcd of the curve between points c and d, and if they are sufficiently close, linear approximation is possible. In other words, Lab is
Lab=√{(x2-x1) ² + (y2-y1) ² + (z2-z1) ² }
Since the bottom center line 35 and the outer peripheral contours 21 and 22 have the same shape,
y2-y1=z2-z1
Therefore, the length Lab is
Lab=√{(x2-x1) ² +2(z2-z1) ² }...It can be expressed as equation (1).

Similarly, the length Lcd is
Lcd=√{(x4-x3) ² + (y4-y3) ² + (z4-z3) ² }
So, since it is on the X-Z plane,
y4=y3=0
It is. Also, since the height direction (Z direction) does not change,
z3=z1, z4=z2
As, the length Lcd is
Lcd=√{(x4−x3) ² +(z2−z1) ² }...It is expressed as equation (2).

here,
Lab = Lcd
Therefore, from equations (1) and (2),
√{(x2-x1) ² +2(z2-z1) ² }
=√{(x4-x3) ² +(z2-z1) ² }
So, the length of the length Lcd in the horizontal direction (X direction) is
x4−x3=√{(x2−x1) ² +(z2−z1) ² }...Equation (3).

From the above, in order to find the ideal bottom seal line 26 before filling from the bottom seal line 36 during liquid filling, it is possible to find the ideal bottom seal line 26 before filling if the values of the bottom seal line 36 in the X and Z directions are available. 35 or the bottom center line 35 converted from the outer peripheral contours 21 and 22.

A method for setting the bottom seal line 26 in this embodiment will be described below.

To set the bottom seal line 26 in the self-supporting packaging bag 10 of this embodiment, first, with the standing pouch 10 filled with a predetermined amount of liquid, the external shape and bottom shape are measured using a 3D scanner or the like. .

From the obtained external shape data, the shape of the surrounding outer peripheral contours 21 and 22 at the height position of the seal intersection 18 is extracted, and the size of the radius of curvature R2 (see FIG. 5) of the curve near the seal intersection 18 is read.

As mentioned earlier, the outer circumferential contours 21 and 22 at the height position of the bottom center line 35 and the seal intersection 18 have the same shape, so the following calculation can be performed from the outer circumferential contours 21 and 22 shape data. , it is possible to determine the shape of the bottom seal line 26 that is not distorted in accordance with the actual shape of the outer peripheral contours 21 and 22. Note that since the bottom surface 20 is bilaterally symmetrical, this calculation was performed only for the right half.

As shown in FIG. 5, in the measurement data of the outer peripheral contours 21, 22 at the height of the seal intersection 18 parallel to the horizontal plane (XY plane), the values of the Y-axis direction data and Z-axis direction data are exchanged, and the most The data is shifted so that the bulging central portion (X=0) becomes the origin, and then converted into data corresponding to the bottom center line 35 (see FIG. 4).

FIG. 7 is an explanatory diagram showing a calculation method for calculating the bottom seal line in the self-supporting packaging bag of this embodiment.
As shown in FIG. 7, the coordinates of the center of the bottom surface 20 in the left-right direction (X direction) are the origin (x ₀ , z ₀ )
and the nth coordinate on the bottom center line 35 is
(x _n , z _n )
shall be. The length LXn in the X direction of the n-1st and nth points on the bottom seal line 26 to be determined is determined by the equation (3) shown above.
LXn=√{(X _n -X _n-1 ) ² + (Z _n -Z _n-1 ) ² }
It is calculated as follows.

By sequentially calculating the length LXn from the origin (x ₀ , z ₀ ), the optimal coordinates (X _n , Z _n ) of the bottom seal line 26 are determined.

To summarize the above calculations, the coordinates (X _n , Z _n ) of the bottom seal line 26 are calculated from the coordinates (x _n , z _n ) of the bottom center line 35 as follows.
<When n=0>
X ₀ =x ₀
Z ₀ = z ₀
<When n≧1>
X _n =X _n-1 +√{(x _n -x _n-1 ) ² +(z _n -z _n-1 ) ² }
Z _n =z _n

The seal shape data obtained here was simplified to find the radius of curvature R of the convex curve 26Cx near the seal intersection 18 position and the radius of curvature of the concave curve 26Cb at the center of the bottom, and they were connected by two straight lines 26Lb. This was used as the bottom seal line 26 of this embodiment.

Here, the value of R will be verified in detail.

Considering that the width dimension of the self-supporting packaging bag 10 before and after liquid filling changes from dimension W to dimension W2, the radius of curvature R is calculated as follows.
R=(W/W2)×R2
That's a good thing.

Here, the radius of curvature R is
R>(W/W2)×R2
In this case, the bag cannot be opened sufficiently in the Y direction (depth direction) during filling, and stress is constantly applied inward to the bag near the seal intersection 18 of the bottom seal line 26, causing the bag to drop. Stress concentration will occur upon impact.

Furthermore, due to the structure of the standing pouch 10, the width dimension W and the width dimension W2 are always W>W2.
Therefore, at least the radius of curvature R and the radius of curvature R2 are
R>R2
The relationship will be as follows.

From the above. In the present invention, the value of the radius of curvature (R) of the curve 26Cx near the intersection point is (W/W2)×R2≧R>R2... By setting it within the range of formula (4), distortion will not occur and the This provides the effect that stress concentration does not occur.

Next, the amount of distortion of the bottom portion 20 in this embodiment will be explained based on FIG. 8.
FIG. 8 is a perspective view for explaining a comparison of the amount of distortion of the bottom surface of the self-supporting packaging bag according to the present embodiment.

In the self-supporting packaging bag 10 according to the present embodiment, at a certain position Px in the width direction (X direction), the depth direction (Y direction) of the bottom portion 20 is approximately linear, and almost coincides with the height 35z of the bottom center line 35. There is. This means that at position Px, there is almost no difference dz between the height 20z of the bottom surface 20 in the depth direction (Y direction) and the height 35z of the bottom center line 35.

In reality, the difference dz does not become zero due to elongation of the front laminated film 11, back laminated film 12, and bottom tape 13 due to the internal pressure of the filled liquid, and the influence of the rigidity of the base layer. For example, the distortion of the bottom part 20 can be reduced by setting the proportion of all the coordinate points of the bottom part 20 where dz>1 mm is 30% or less, or 20% or less.

Therefore, the bottom seal line 26 in the self-supporting packaging bag 10 of this embodiment is a convex curve 26Cx that is upwardly convex near the seal intersection point 18 in the planar state of the self-supporting packaging bag 10, and the seal intersection of this convex curve 26Cx A tangent 19 at 18 is formed parallel to the folding line (edge line) 15 of the bottom tape 13, as shown in FIG.

When the self-supporting packaging bag 10 of this embodiment is filled with contents, the XY plane projected shape of the bottom seal line 36 after filling shown in FIG. 4 and the outer periphery at the height position of the seal intersection 18 shown in FIG. The XY plane shapes of the contours 21 and 22 are formed to match.

At the same time, after filling the contents, the XZ plane shape of the bottom seal line 36 shown in FIG. 4 and the XY plane shape of the bottom center line 35 shown in FIG. 4 are formed to be the same shape. ing.
Further, the bottom centerline 35 and the outer peripheral contour 21 at the height of the seal intersection point 18 are formed to have the same shape.

The convex curve 26Cx near the seal intersection 18 on the bottom seal line 26 in a planar state shown in FIG. 3 corresponds to the shape near the intersection 18 on the XY plane projected shape of the bottom seal line 36 after filling shown in FIG. It is formed so as to match the shape of the outer circumferential contour 21 (see FIG. 5) of the portion.

In the self-supporting packaging bag 10 of this embodiment, as described above, by setting the shape of the bottom seal line 26, distortion does not occur on the bottom surface 20 where the bottom tape 13 is spread, and stress is distributed near the seal intersection 18. This prevents the bag from being concentrated due to the impact of falling, thereby preventing the bag from breaking due to the impact of the fall.

Although this embodiment has been described as an example of filling liquid, it can also be applied to powder, granules, or a large number of solid objects that are somewhat larger than granules and can be moved inside. is possible.

In this embodiment, the bottom seal line 26 has a shape in which the convex curve 26Cx and the concave curve 26Cb are connected by a straight line 26Lb, but they can also be smoothly connected by a curve.

Moreover, as the laminated films 11, 12, and 13 used in the self-supporting packaging bag 10 according to the present embodiment, a laminate normally used for flexible packaging bags can be used. As the base material, paper, metal foil, or synthetic resin film consisting of one layer or several layers is used. Examples include low density polyethylene resin (LDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (LLDPE), polypropylene resin (PP), polyolefin resins such as polyolefin elastomers, and polyethylene terephthalate resins. (PET), polyester resins such as polybutylene terephthalate resin (PBT), polyethylene naphthalate resin (PEN), cellulose resins such as cellophane, cellulose triacetate (TAC), polymethyl methacrylate (PMMA) resin, ethylene- Vinyl acetate copolymer resin (EVA), ionomer resin, polybutene resin, polyacrylonitrile resin, polyamide resin, polystyrene resin (PS), polyvinyl chloride resin (PVC), polyvinylidene chloride resin (PVDC) , polycarbonate resin (PC), fluororesin, urethane resin, and other synthetic resin films, paper, metal foil, etc. are used singly or in combination. The base material includes a printing layer and an adhesive layer as necessary.

Polyolefin resins are generally used as the sealant layer, specifically low-density polyethylene resin, medium-density polyethylene resin, linear low-density polyethylene resin, ethylene/vinyl acetate copolymer, ethylene/α-olefin. Ethylene resins such as copolymers, polypropylene resins such as homopolypropylene resins, propylene/ethylene random copolymers, propylene/ethylene block copolymers, propylene/α-olefin copolymers, etc. are used. A multilayer film made of a composite of these resins may also be used.

Specific examples of the structure of the laminate include a film with a structure of PET/printed layer/adhesive layer/stretched polyamide resin film (hereinafter abbreviated as ONY)/adhesive layer/LLDPE, and a film with a structure of PET/printed layer/adhesive layer/LLDPE, or ONY/adhesive layer/LLDPE. , ONY/adhesive layer/ONY/adhesive layer/LLDPE, paper/LDPE/aluminum foil/LDPE, paper/LDPE, and the like.
In this embodiment, the upper part of the self-supporting packaging bag (standing pouch) 10 has been described as having a linear outline, but it is not limited to this configuration, and may have a spout formed near the corner. It is also possible to have a zipper that is linear in the width direction and that can be fitted into a male and a female that can be resealed after opening.

Examples according to the present invention will be described below.

The standing pouch 10 shown in FIG. 1 was formed as an example using the following design values so as to have the bottom seal line 26 shown in FIG. 3.
Film composition: ONY (stretched nylon, 15 μm) / VMPET (aluminum-deposited PET film, 12 μm) / LLDPE (TUXFCS, manufactured by Tocello Co., Ltd., 150 μm)
External dimensions: width 200mm, height 300mm, bottom folding depth 60mm
W=185mm (design value)
R=6.0mm (design value)

Similarly, a standing pouch was formed as a comparative example using the conventional bottom seal shape 126 shown in FIG.

Next, after filling these standing pouches with a predetermined amount (1320 ml) of liquid (water), the upper ends are sealed and sealed, and the external and bottom shapes of each are determined using a 3D scanner (Eva manufactured by Artec). was measured.

From the external shape data, the surrounding outer peripheral shapes 21 and 22 at the height position of the seal intersection point 18 were extracted, and the size of the radius of curvature R2 of the curve near the seal intersection point 18 shown in FIG. 5 was read. These measured values are
W2=134.4mm (actual measurement value)
R2=4.8mm (actual measurement value)
Met.

From these results, it can be seen that the value of R satisfies the above formula (4).

Next, the amount of distortion of the bottom portion 20 was measured.

Similarly, in the comparative example and the example, the height of the bottom surface 20 in the depth direction (Y direction) with respect to the height 35z of the bottom center line 35 at a certain position Px in the width direction (X direction) is determined from the 3D scan data of the bottom surface 20. The absolute value of the difference dz from 20z was investigated.

Here, if there is no distortion at all on the bottom surface 20, all dz becomes 0.
As a result of calculations for the position Px as the entire width dimension W2, the percentage of all coordinate points of the bottom portion 20 where dz<1 mm was about 66% in the comparative example, but about 80% in the example. there were. From this result, it was confirmed that the distortion at the bottom was smaller in the example.

Next, a drop impact test was conducted on the above comparative examples and examples.
The test conditions are shown below.
Filling liquid: water (4℃)
1320ml
Falling height: 1.0m, 1.5m
Displacement of seal intersection 18 position: +1mm, -1mm
Test conditions: Dropped in an upright position Note that the deviation of the seal intersection 18 position is positive when the seal intersection 18 is above the folding line (ridge line) 15 of the bottom tape 13, as shown by G in Figure 9. , is defined as a negative value if the bottom tape 13 is at the bottom, and this was incorporated into the test conditions in consideration of the positional shift of the bottom tape 13 during bag making.

The results were as follows.

When dropped from a height of 1.0 m, out of 25 bags in each comparative example, the bags did not break when the deviation of the seal intersection 18 position was +1 mm, but 5 bags broke when the deviation of the seal intersection 18 position was -1 mm.
On the other hand, in the examples, no bags were broken even when the deviation of the seal intersection point 18 was +1 mm or -1 mm.

Similarly, when dropped from 1.5 m, out of 50 bags in each case, in the comparative example, 7 bags were broken when the deviation of the seal intersection 18 position was +1 mm, and 8 bags were broken when the deviation was -1 mm, whereas in the example, 7 bags were broken. Only two bags were broken when the deviation of the seal intersection point 18 was +1 mm and -1 mm.

From these results, it was confirmed that the present invention reduces the occurrence of distortion at the bottom surface and is effective in improving drop strength.

As an example of how the present invention can be used, it can be used not only for general refill standing pouches (liquids, powders, etc.), but also for balloon-like bags with the same structure at the bottom and top. Since it is durable, it can be used for things such as air packing and stick balloons for cheering.

10...Self-supporting packaging bag (standing pouch)
11...Surface laminated film 12...Back layered film 13...Bottom tape 14...Side seal part 15...Ridge line 16...Bottom seal part 17...Storage part (filling part)
18... Seal intersection point 19... Tangent line 20... Bottom surface 21, 22... Outer circumferential contour 24... Side seal line 25... Straight line connecting the intersection points during filling 26... Bottom seal line 26Cb... Concave curve 26Lb... Straight line 26Cx... Convex curve 35... Bottom Center line 36...Bottom seal line (when filling)
126...Bottom seal line (conventional)
W... Inner width dimension before filling W2... Inner width dimension after filling R... Radius of curvature of 26Cx section R2... Radius of curvature of outer peripheral contour after filling

Claims (2)

The sealant layers of the front laminated film and the back laminated film, each having a base material layer and a sealant layer, are faced to each other, and a bottom tape having a base material layer and a sealant layer is placed between them, with the sealant layer facing outward. A method for designing a self-supporting packaging bag that is folded and inserted and seals opposing sealant layers, the bag comprising:
The boundary line between the inner edge of the bottom seal part and the unsealed part, which is the part where the surface laminated film and the bottom tape and the back surface laminated film and the bottom tape are sealed, is defined as a bottom seal line, and the surface laminated film The boundary line between the inner edge of the side seal part, which is the part where and the back layered film are sealed, and the unsealed part is defined as the side seal line,
A temporary packaging bag formed using the surface laminated film, the back laminated film, and the bottom tape and having the same external dimensions as the self-supporting packaging bag before filling is filled with enough liquid to fully expand the bottom tape. Fill and establish filling status,
Measure the outer peripheral shape of the temporary packaging bag excluding the side seal portion at the height of the seal intersection when the temporary packaging bag is viewed from above in the filled state;
The bottom seal line of the self-supporting packaging bag is made into a convex curve that is upwardly convex in the vicinity of the seal intersection, and the radius of curvature R of this convex curve is set between the seal intersections in the temporary packaging bag before filling with contents. When the left and right width dimension of is W, the left and right width dimension between the seal intersection points in the temporarily manufactured packaging bag in the filled state is W2, and the radius of curvature near the seal intersection in the outer peripheral shape is R2,
(W/W2)×R2≧R>R2
set to satisfy,
How to design a free-standing packaging bag. The sealant layers of the front laminated film and the back laminated film, each having a base material layer and a sealant layer, are faced to each other, and a bottom tape having a base material layer and a sealant layer is placed between them, with the sealant layer facing outward. A method for designing a self-supporting packaging bag that is folded and inserted and seals opposing sealant layers.
The boundary line between the inner edge of the bottom seal part and the unsealed part, which is the part where the surface laminated film and the bottom tape and the back surface laminated film and the bottom tape are sealed, is defined as a bottom seal line, and the surface laminated film The boundary line between the inner edge of the side seal part, which is the part where and the back layered film are sealed, and the unsealed part is defined as the side seal line,
A temporary packaging bag formed using the surface laminated film, the back laminated film, and the bottom tape and having the same external dimensions as the self-supporting packaging bag before filling is filled with enough liquid to fully expand the bottom tape. Fill and establish filling status,
Measure the outer peripheral shape of the temporary packaging bag excluding the side seal portion at the height of the seal intersection when the temporary packaging bag is viewed from above in the filled state;
The bottom seal line of the self-supporting packaging bag is a convex curve that is upwardly convex in the vicinity of the seal intersection, and this convex curve is defined in the vicinity of the seal intersection of the outer peripheral shape of the temporarily fabricated packaging bag in the filled state. set to match the shape of,
How to design a free-standing packaging bag.

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