JP7589684B2 - Method for three-dimensional processing of film, compression mold, film, and film molded body - Google Patents

Description

The present invention relates to a method for three-dimensional processing of a film, in which the film is subjected to three-dimensional processing by cold compressing the film, a compression mold, a film, and a film molded body.

In recent years, there has been a demand for film molded products such as pouches for filling with semi-fluid or fluid contents such as food, beverages, detergents, etc., to be differentiated from competitors' products and to increase their commercial value by applying three-dimensional processing to the film.

As a method for three-dimensionally forming such films, a method for forming a bag-shaped container with an embossed pattern has been proposed, in which a specific portion of the film is partially heated and cooled to form an embossed pattern (see, for example, Patent Document 1).

However, the method described in Patent Document 1 has problems such as the need for cooling time after hot press molding, which lengthens processing time, the need for heating and cooling, which consumes a lot of energy, the need to provide a film cooling section within the equipment, which necessitates significant design changes to existing equipment, and the risk of film strength being reduced due to the formation of thin, easily breakable portions in the film caused by embossing the heated film. In addition, when embossing is performed by sandwiching the film between a male and female mold, it is difficult to form a complex shape with fine irregularities.

Therefore, in Patent Document 2 and other documents, the present inventors proposed a three-dimensional processing method for the film by cold compressing the compressed area of the film as one solution to the problems in hot press processing described above.

JP 2004-142132 A JP 2014-46655 A JP 2010-168109 A

Here, the three-dimensional processing applied to film molded articles such as pouches may be desired to impart localized unevenness to the film, or may be desired to form a gentle mountain-like curvature over a wide area of the film in the film plane direction, such as when the film is given a so-called diamond cut shape as disclosed in Patent Document 3.

However, although the three-dimensional processing method described in Patent Document 2 is suitable for forming localized unevenness near the compressed areas of the film, it is not suitable for forming a gentle curvature in the film over a wide area in the film's planar direction, and therefore new ideas are required to form a gentle curvature in the film.

Therefore, the present invention aims to solve these problems by providing a three-dimensional processing method for film, a compression mold, a film, and a film molded body that can form a gentle curve in the film while having a simple configuration, shortening processing time and reducing energy consumption, preventing the equipment from becoming large, forming complex shapes, and avoiding a decrease in film strength.

The three-dimensional processing method of the present invention is a three-dimensional processing method for a film, which performs three-dimensional processing on a film having a first layer and a second layer having a larger elongation than the first layer by cold compressing the film in a thickness direction using a compression mold, wherein the compression mold is provided with a mountain folding convex portion having a mountain folding compression surface including a mountain folding contact effective area that actually contacts the film compressed area of the film when the film is compressed, the mountain folding convex portion cold compresses the film compressed area so that the width of the mountain folding contact effective area in a lateral direction perpendicular to the longitudinal direction of the mountain folding convex portion is 1.0 mm to 3.5 mm, the inclination angle with respect to the lateral direction at both left and right ends of the mountain folding contact effective area is 147° or more, and the compression molding ratio of the film by the mountain folding convex portion is 20% or more of the thickness of the film, thereby causing the film to protrude toward the first layer side, forming a mountain folding portion curved in a mountain shape in the film, and the mountain folding portion compresses the film with a compression force of 1.5 to 4.5 g/cm against a flat surface. The problem is solved by providing a region that bulges away from the flat surface when adsorbed under any of the vacuum conditions in the range of ² , the width in the lateral direction of which is 150% or more of the width in the lateral direction of the effective contact region for mountain folding.
The compression mold of the present invention is a compression mold for performing three-dimensional processing on a film by cold compressing a film having a first layer and a second layer having a greater elongation than the first layer in the thickness direction, and the compression mold includes a mountain folding convex portion for forming a mountain-shaped curved mountain folding portion in the film by cold compressing the compressed area of the film, causing the film to protrude toward the first layer side, and the mountain folding convex portion has a mountain folding compression surface including a mountain folding effective contact area that actually contacts the film compressed area of the film when the film is compressed, and the surface roughness (Ra) of the mountain folding effective contact area is 2 μm or less, and the mountain folding compression surface is formed so that the width of the mountain folding effective contact area in the lateral direction perpendicular to the longitudinal direction of the mountain folding convex portion is 1.0 mm to 3.5 mm, and the inclination angle with respect to the lateral direction at both left and right ends of the mountain folding effective contact area is 147 ° or more, thereby solving the above problem.
The film of the present invention is a film having mountain folds and valley folds formed therein, and is formed as a laminated film having a first layer and a second layer having greater elongation than the first layer, the mountain folds have a cross-sectional shape curved in a mountain shape protruding toward the first layer side, the valley folds have a cross-sectional shape recessed in a valley shape toward the second layer side, the mountain folds have processing marks extending along the longitudinal direction of the mountain folds at their middle portions on both left and right sides of the apex, the distance between the left and right processing marks in the lateral direction perpendicular to the longitudinal direction is formed to be 1.0 mm or more and 3.5 mm or less , the valley folds have two valley-shaped fold lines extending along the longitudinal direction and bent so as to be recessed toward the second layer side, and the distance between the two valley-shaped fold lines is set to less than 1.0 mm , thereby solving the above problem.
The film molding of the present invention is a film molding having the film, and the film has a three-dimensional shape formed by combining a plurality of the mountain fold portions and a plurality of the valley fold portions, thereby solving the above problem.

In this specification, "cold" refers to a temperature range lower than the Vicat softening temperature of the film, including room temperature (20°C ± 15°C).
There are various indices that indicate the "elongation" of a film, including, for example, elastic modulus, Young's modulus, yield elongation, and breaking elongation.

According to the present invention, by subjecting a film to cold compression molding in the thickness direction, it is possible to shorten processing time and reduce energy consumption, prevent the need for large-scale equipment, form complex shapes, and avoid a decrease in film strength, compared to the case of three-dimensional processing by hot press molding, and it is also possible to achieve the effects described below.

First, according to the inventions of claims 1, 9, 11, 12, and 13 , the compression surface for mountain folding is formed so that the inclination angle with respect to the horizontal direction at both left and right ends of the effective contact area for mountain folding is 147° or more. This makes it possible, with a simple configuration, to suppress the restriction of movement of the first layer side of the film due to contact with the compression surface for mountain folding at both left and right ends of the effective contact area for mountain folding that contacts the compressed area of the film when the film is compressed, so that the periphery of the compressed area of the film can be curved into a gentle mountain shape over a wide area.
That is, when the movement of the first layer side of the film is restricted by contact with the mountain folding compressed surface at both left and right ends of the mountain folding contact effective area during film compression, the range of the film in the film plane direction in which deformation occurs during film compression is limited due to the restriction. In other words, the difference in deformation between the compressed and uncompressed parts of the film becomes large. Therefore, when the compression of the film is released, a large deformation occurs around the boundary between the compressed and uncompressed parts. On the other hand, according to the invention according to claim 1, the mountain folding compressed surface is formed so that the inclination angle with respect to the lateral direction at both left and right ends of the mountain folding contact effective area is 147° or more, so that it is possible to suppress the movement of the first layer side of the film from being restricted by contact with the mountain folding compressed surface at both left and right ends of the mountain folding contact effective area, so that the range of the film in the film plane direction in which deformation occurs during film compression becomes wide, and each part of the film is suppressed from being significantly deformed (elongated, etc.) during film compression, and the periphery of the film compressed area can be curved gently in a mountain shape over a wide range after the film compression is released.
In addition, since it is possible to suppress unevenness in the deformation of the film when it is compressed, it is possible to suppress large changes in the thickness of the film after release from compression, and to suppress the occurrence of local deformation (undulations) in the film, or, even if local deformation does occur in the film, to reduce the deformation, thereby suppressing a decrease in film strength.
In addition, since the mountain fold shape can be formed using only a convex mold, it is possible to form even fine shapes.
Furthermore, according to the present invention, regardless of whether the film is compressed from the first layer side or the second layer side of the film using a compression mold, the film will protrude toward the first layer side, which has less elongation, and a mountain fold portion can be formed.

The mechanism behind the phenomenon of protrusion towards the first layer that occurs when a film having a first layer and a second layer that has greater elongation than the first layer is cold compressed in the thickness direction at a compression molding ratio of 20% or more is not entirely clear. However, it is thought that this is due to the fact that when the film thickness is restored after the compression force is removed, the first layer, which has relatively less elongation, only recovers slightly, while the second layer, which has relatively more elongation, recovers significantly.

According to the invention of claims 2 to 6, the movement of the first surface side of the film can be effectively prevented from being restricted by contact with the mountain-fold compression surface, and the periphery of the compressed region of the film can be curved gently into a mountain shape.
According to the inventions of claims 7, 10, and 11 , it is possible to form mountain folds and valley folds in the film by compressing the film from the same side of the film using the mountain fold convex portions and the valley fold convex portions, making it easy to perform three-dimensional processing of the film.
Furthermore, according to the present invention, regardless of whether the film is compressed from the first layer side or the second layer side of the film using a compression mold, the film will be recessed toward the second layer side, which has greater elongation, and a valley fold portion can be formed.
According to the inventions of claims 8 and 10, the mountain fold convex portion and the valley fold convex portion are formed in the same compression mold, so that the mountain fold portion and the valley fold portion can be formed together by compressing the film using the compression mold.

FIG. 2 is an explanatory diagram showing a pouch according to one embodiment of the present invention. FIG. 1A to 1C are explanatory diagrams illustrating a three-dimensional processing method for a film. FIG. 11 is an explanatory diagram illustrating a method for processing a mountain fold. FIG. 4 is an explanatory diagram illustrating a method for processing a valley fold. FIG. 13 is an explanatory diagram showing a modified example of a mountain-folding convex portion. FIG. 4 is an explanatory diagram showing a test mold used in a test conducted to confirm the conditions for forming a mountain fold portion. Table showing test results.

Below, a pouch 10 as a film molded body, which is one embodiment of the present invention, is described with reference to the drawings.

First, as shown in Figure 1, the pouch 10 is formed into a bag shape by heat welding the outer edges of each film 20 used as the material, and contains liquid contents such as detergent or shampoo.

As shown in FIG. 1, the pouch 10 is composed of front and back films 20 arranged opposite each other, and a gusset film (not shown) that is folded in half between the front and back films 20 at the bottom of the pouch 10, and is configured as a standing pouch with a gusset formed at its bottom by forming a bag-making seal section in which each film 20 is heat-welded at a predetermined location.

As shown in Figures 3 to 5, each film 20 is formed as a laminated film by laminating and bonding a first layer 21 arranged on the first surface 20a side of the film 20 and a second layer 22 arranged on the second surface 20b side of the film 20 and having a greater elongation than the first layer 21 (having a property of relatively greater recovery after removal of compression force than the first layer 21).
Each film 20 is positioned so that the first layer 21 faces the outside of the pouch 10 .

As a specific material for the first layer 21, a stretched film can be suitably used, and a polyamide film such as a nylon film, or a polyester film such as a polyethylene terephthalate (PET) film can be suitably used.
Specific materials for the second layer 22 include low-, medium-, and high-density polyethylene (PE), linear low-density polyethylene (LLDPE), linear very low-density polyethylene (LULDPE), isotactic polypropylene (PP), propylene-ethylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ionically crosslinked olefin copolymer (ionomer), and modified olefin resins such as olefin resins graft-modified with ethylenically unsaturated carboxylic acid or anhydride thereof.

The first layer 21 has a thickness of about 10 to 40 μm, and the second layer 22 has a thickness of about 18 to 200 μm. The first layer 21 is formed to be about 1.8 to 20 times thinner than the second layer 22.
The total thickness of the film 20 (including layers other than the first layer 21 and the second layer 22, if the film 20 has layers other than these layers) is about 30 to 300 μm.

As shown in FIG. 1, each film 20 has a three-dimensional shape formed by combining a plurality of mountain folds 30 and a plurality of valley folds 40, and in this embodiment, a so-called diamond cut shape is formed.
The diamond cut shape is a shape that combines a plurality of mountain fold lines that extend linearly along the planar direction and are arranged in a lattice pattern, and a valley fold line that extends linearly along the planar direction on the diagonal of each rectangular portion formed by the plurality of mountain fold lines. In the case of this embodiment, the three-dimensional shape as shown in FIG. 1 is specifically a diamond cut shape formed by combining a plurality of mountain folds 30 that extend linearly along the film planar direction and are arranged in a lattice pattern, and a valley fold 40 that extends linearly along the film planar direction on the diagonal of each rectangular portion formed by the plurality of mountain folds 30, and each lattice width is 22 mm. In addition, diamond cut shapes with lattice widths of 16 mm and 10 mm can also be formed, and according to the mountain folds 30 and the valley folds 40 of this embodiment, the lattice width can be appropriately selected according to the size of the pouch 10, such as the length and width, to reproduce diamond cut shapes from shapes with wide lattice widths to shapes with narrow lattice widths.

As shown in Fig. 4, the mountain fold 30 is a portion having a cross-sectional shape curved in a mountain shape so as to protrude toward the first surface 20a of the film 20 (over the entire thickness direction of the film 20). The apex of the mountain fold 30 extends linearly in the pouch planar direction as shown in Fig. 1.
Here, mountain fold portion 30 is a portion in which, when film 20 is adsorbed to a flat surface (flat adsorbed surface) under any vacuum condition (vacuum strength) in the range of 1.5 to 4.5 g/ ^cm2 , the width in the lateral direction (direction perpendicular to the longitudinal direction of said region, left-right direction on the paper in FIG. 4) of a region that bulges away from said flat surface is 150% or more of the width W1 in the lateral direction (direction perpendicular to the longitudinal direction of said region, left-right direction on the paper in FIG. 4) of mountain fold effective contact region 61a of mountain fold convex portion 60 described later (direction perpendicular to the longitudinal direction of mountain fold effective contact region 61a, left-right direction on the paper in FIG. 4).

As shown in Fig. 5, the valley fold 40 is a portion having a cross-sectional shape that is recessed in a valley shape toward the second surface 20b of the film 20 (over the entire thickness direction of the film 20). The bottom of the valley fold 40 extends linearly in the film plane direction as shown in Fig. 1.

Next, the compression mold 50 used for three-dimensional processing of the film 20 will be described below.

As shown in Figures 3 to 5, the compression mold 50 compresses the film 20 in the thickness direction with an anvil 80 arranged on the opposite side of the film 20, and as can be seen from Figures 1 and 2, it has a plurality of mountain fold protrusions 60 and a plurality of valley fold protrusions 70 on the same surface, which are formed in a positional relationship corresponding to the positional relationship of the plurality of mountain folds 30 and the plurality of valley folds 40 of the film 20. Note that in this embodiment, a form in which the film 20 is compressed from the first layer 21 side of the film 20 by the mountain fold protrusions 60 and the valley fold protrusions 70 is described, but even if the film 20 is compressed from the second layer 22 side by the mountain fold protrusions 60 and the valley fold protrusions 70, the behavior of the film 20 protruding toward the first layer 21 side or recessing toward the second layer 22 side is approximately the same as the form in which the film 20 is compressed from the first layer 21 side.

As shown in FIG. 2, each mountain folding protrusion 60 is formed so as to extend linearly.
As shown in FIG. 4, each mountain-folding protrusion 60 has a mountain-folding compression surface 61 which is a portion that compresses film 20 (i.e., a portion that comes into contact with film 20 when the film is compressed).
As shown in FIG. 4, the mountain folding compression surface 61 (the mountain folding effective contact area 61a) is formed by curving within an imaginary plane perpendicular to the longitudinal direction (the direction perpendicular to the paper surface of FIG. 4) of the mountain folding convex portion 60 and is composed of a single convex curved surface that is convex toward the compression direction (toward the anvil 80 side).
The radius of curvature R of the convex curved surface of the mountain-folding compression surface 61 is set to 1 to 20 mm.
In addition, the surface roughness (Ra) of the mountain folding compressed surface 61 (the mountain folding effective contact area 61a) is preferably set to 2 μm or less. Note that any method may be used to reduce the surface roughness (Ra) of the mountain folding compressed surface 61, such as polishing the mountain folding compressed surface 61 to a mirror finish.
The mountain fold compression surface 61 has a mountain fold effective contact area 61a which is a portion that actually comes into contact with the first film compressed area of the film 20 when the film is compressed (when the film 20 is compressed by the mountain fold convex portion 60).
As shown in FIG. 4, the mountain folding compression surface 61 is formed so that the width W1 of the mountain folding effective contact area 61a in the horizontal direction perpendicular to the longitudinal direction of the mountain folding convex portion 60 (and the compression direction of the film 20 by the mountain folding convex portion 60) is 1.0 mm or more and 3.5 mm or less.
In addition, the mountain folding compression surface 61 is formed so that the inclination angle Θ with respect to the horizontal direction at both left and right ends of the mountain folding contact effective area 61a (see FIG. 7. When the mountain folding compression surface 61 is configured as a convex curved surface as in this embodiment, the inclination angle with respect to the horizontal direction of the tangent of the mountain folding compression surface 61 at both left and right ends of the mountain folding contact effective area 61a) is 147° or more.

As shown in FIG. 2, each of the valley folding convex portions 70 is formed so as to extend linearly.
As shown in FIG. 5, each valley fold protrusion 70 is configured as a rectangular parallelepiped protrusion, and has a valley fold compression surface 71 which is the portion that compresses the film 20 (i.e., which comes into contact with the film 20 when the film is compressed).
In this embodiment, as shown in FIG. 5, the valley folding compression surface 71 has two corners 71b bent at a right angle and extending along the longitudinal direction of the valley folding convex portion 70 (the direction perpendicular to the paper surface of FIG. 5).
The valley fold compression surface 71 has a valley fold effective contact area 71a which is a portion that actually comes into contact with the second film compressed area of the film 20 when the film is compressed (when the film 20 is compressed by the valley fold protrusion 70).
The valley fold compression surface 71 is formed so that the width W2 of the valley fold effective contact area 71a in the horizontal direction perpendicular to the longitudinal direction of the valley fold convex portion 70 (and the compression direction of the film 20 by the valley fold convex portion 70) is less than 1.0 mm.

Next, the three-dimensional processing method for film 20 in this embodiment will be described below.

First, the three-dimensional processing of the film 20, i.e., the formation of the mountain folds 30 and the valley folds 40, is performed by sandwiching and compressing the film 20 between the mountain fold protrusions 60 and the valley fold protrusions 70 of the compression mold 50 and an anvil 80 with a flat compression surface that is disposed on the opposite side of the film 20, as shown in Figures 3 to 5. Here, the anvil 80 is configured to come into contact with the entire surface of the film 20 when the film 20 is compressed.

The formation of the mountain fold portion 30 using the mountain fold convex portion 60 and the formation of the valley fold portion 40 using the valley fold convex portion 70 are specifically described below.

First, as shown in FIG. 4, the mountain fold portion 30 is formed by cold compressing the first film compressed area from the first surface 20a side of the film 20 using the mountain fold convex portion 60, causing the periphery of the first film compressed area of the film 20 to protrude toward the first surface 20a side, thereby forming a mountain fold portion 30 curved in a mountain shape in the film 20.

Here, the mechanism behind the phenomenon in which film 20 protrudes toward first surface 20a when the first film compressed area of film 20 is cold compressed from the first surface 20a side of film 20 is not entirely clear, but it is thought that this is due to a difference in the degree of deformation between the first surface 20a side and the second surface 20b side of film 20 when the film is compressed, and a difference in the behavior of the thickness of film 20 when it is restored after the compressive force is removed, between the restoration of the first surface 20a side and the restoration of the second surface 20b side of film 20.
To explain in more detail, when the film 20 is constructed from a laminated film consisting of a first layer 21 and a second layer 22 that has greater elongation than the first layer 21, as in this embodiment, it is believed that the reason for this is that when the thickness of the film 20 is restored after the compression force is removed, the first layer 21, which has relatively less elongation, only recovers slightly, while the second layer 22, which has relatively more elongation, recovers greatly.

Furthermore, if the movement of the first surface 20a of the film 20 is restricted by contact with the mountain-fold compression surface 61 during film compression, the range of the film 20 in the film plane direction in which deformation occurs during film compression becomes limited due to the restriction. In other words, the difference in deformation between the compressed and uncompressed portions of the film becomes large. Therefore, when the film is released from compression, large deformation occurs around the boundary between the compressed and uncompressed portions.
On the other hand, in the present embodiment, the inclination angle Θ of the mountain fold compression surface 61 with respect to the lateral direction at both left and right ends of the mountain fold contact effective area 61a is formed to be 147° or more. This makes it possible to suppress the restriction of movement of the first surface 20a of the film 20 due to contact with the mountain fold compression surface 61 at both left and right ends of the mountain fold contact effective area 61a. As a result, the range in the film planar direction of the film 20 that deforms during film compression is wide, and it is possible to suppress large deformation of each part of the film 20 during film compression. As a result, after the film compression is released, the periphery of the first film compressed area can be curved into a gentle mountain shape over a wide area, as shown in FIG. 4.

In addition, the formation of the mountain fold portion 30 using the mountain fold convex portion 60 is carried out under the following conditions.

First, the width W1 of the mountain folding effective contact area 61a of the mountain folding compression surface 61 shown in Fig. 4 is set to 1.0 mm or more and 3.5 mm or less as described above. If the width W1 of the mountain folding effective contact area 61a is smaller than 1.0 mm, the pressure applied to the film 20 by the mountain folding protrusions 60 becomes too high, making it difficult for the film 20 to protrude toward the first surface 20a.
As described above, the compression molding ratio of the film 20 by the mountain folding convex portion 60 is set to 20% or more of the thickness of the film 20. If the compression molding ratio is less than 20% or more, the film 20 does not sufficiently protrude toward the first surface 20a side. However, if the compression molding ratio is too large, the film 20 will stretch excessively and will be damaged, so it is necessary to appropriately set the compression molding ratio at 20% or more.
Furthermore, as described above, the radius of curvature R of the convex curved surface of the mountain-fold compression surface 61 is set to 1 mm to 20 mm. If the radius of curvature R is smaller than 1 mm, the film 20 will be compressed locally, and it will not be possible to form a gently curved mountain shape in the film 20 over a wide area around the first film compressed region as shown in Figure 4.

In addition, in the middle portion of the mountain fold 30 indicated by the symbol 31 in Figure 4, processing marks extending along the longitudinal direction (extension direction) of the mountain fold 30 may be formed on both the left and right sides of the apex of the mountain fold 30.
In addition, the term “middle” in this specification is not limited to the central position between the top of the mountain fold 30 and both left and right ends, but means any position between the top of the mountain fold 30 and both left and right ends.
These processing marks are points where the curvature of the contour line of mountain fold portion 30 has changed significantly when viewed in cross section as shown in Figure 4, or points where the contour line of mountain fold portion 30 has a slight valley-like depression (undulation).
The mechanism by which these processing marks are formed is not clear, but as can be seen from Figure 4, the processing marks are formed near the points compressed by both left and right ends of the mountain fold effective contact area 61a of the mountain fold compression surface 61 in the horizontal direction (direction perpendicular to the longitudinal direction) of the mountain fold convex portion 60. Therefore, it is thought that the cause is that when the film 20 is fully compressed, some bias occurs in the deformation of the film 20 near both left and right ends that come into contact with the film 20 of the mountain fold compression surface 61.
Therefore, the distance between the left and right processing marks in the horizontal direction perpendicular to the longitudinal direction of the mountain fold portion 30 is 1.0 mm or more and 3.5 mm or less, which is the same as the width W1 of the effective contact area 61a for mountain folding of the compression surface 61 for mountain folding.

When the film 20 is adsorbed to a flat surface (flat adsorbed surface) under any vacuum condition in the range of 1.5 to 4.5 g/ ^cm2 , the mountain fold portion 30 thus obtained has a lateral width of the region that bulges away from the flat surface that is 150% or more of the lateral width W1 of the mountain fold protrusion 60 (the distance between the processing marks).

Next, as shown in FIG. 5, with the second surface 20b of the film 20 supported by the anvil 80, the second film compressed area is cold compressed from the first surface 20a of the film 20 by the valley fold protrusion 70, thereby forming the valley fold 40 in which the second film compressed area is recessed toward the second surface 20b of the film 20.

Here, the mechanism behind the phenomenon of the valley fold 40 being formed is not clear, but it is thought that the reason is that when the film is compressed under conditions where the width W2 of the valley fold compression surface 71 is less than 1.0 mm, the plastic deformation on the second surface 20b side (second layer 22 side) of the film 20 caused by film compression has a large effect, causing the film 20 to remain concave towards the second surface 20b side.

The compression molding ratio of the film 20 by the valley fold convex portion 70 is set to 20% or more of the thickness of the film 20, and if it is set to less than 20% of the thickness of the film 20, no visual deformation of the film 20 occurs. However, if the compression molding ratio is too large, the film 20 will stretch excessively and be damaged, so it is necessary to set the compression molding ratio appropriately to 20% or more.

In addition, if the width W2 of the valley fold convex portion is set to 1.0 mm or more, a protrusion phenomenon toward the first surface 20a of the film 20 will occur. Furthermore, if the width W2 of the valley fold convex portion is reduced to less than 1.0 mm, the lower limit value must be set appropriately. Generally, however, if the width W2 of the valley fold convex portion is set to less than 0.5 mm, the pressure on the film 20 will become excessive, making the film 20 more likely to be damaged.

5, in the valley fold 40, two valley-shaped fold lines 41 are formed on both sides of the bottom of the valley fold 40, each of which is bent so as to be recessed toward the second surface 20b. These valley fold lines 41 extend along the longitudinal direction of the valley fold 40.
The mechanism by which these valley-shaped fold lines 41 are formed is also not clear, but as can be seen from Figure 5, valley-shaped fold lines 41 are formed near the points compressed by corners 71b of valley fold compression surface 71, and therefore it is thought that the cause is that, when the film is compressed, a bias in the degree of deformation of film 20 occurs near the points compressed by corners 71b of valley fold compression surface 71 (i.e., near both left and right ends of valley fold compression surface 71).
Therefore, the horizontal distance between these two valley-shaped fold lines 41 is less than 1.0 mm, which is the same as the horizontal width W2 of the valley fold compression surface 71.
Depending on the compression conditions, the area between the two valley-shaped fold lines 41 may exhibit a phenomenon in which it slightly protrudes in a convex manner toward the first surface 20a of the film 20, or the area between the two valley-shaped fold lines 41 may remain almost flat.

The timing for performing the three-dimensional processing of the film 20 described above may be either before filling the pouch 10 with the contents and before heat-welding each film 20, or after forming a seal portion for bag making by heat-welding the film 20 at areas other than the area that will become the filling opening.

In addition, in the example shown in Figure 3 (a), the compression mold 50 and the anvil 80 are configured to approach each other in a linear manner to compress the film, but the specific aspects of the compression mold 50 and the anvil 80 are not limited to this, and for example, as shown in Figure 3 (b), the film 20 may be compressed while rotating a roll-shaped compression mold 50 and a roll-shaped anvil 80.
In addition, in order to simplify the drawings, only one mountain fold convex portion 60 and one valley fold convex portion 70 are shown in Figs. 3(a) and 3(b).

Next, the tests conducted to confirm the conditions for forming the mountain fold portion 30 are described below with reference to Figures 7 and 8.

First, in this experimental example, a test mold 90 was prepared in which the tip width of the tip portion 92 and the radius of curvature (R) of the shoulder portions 93 formed on both sides of the tip portion 92 were variously changed, and films 1 to 3 described below were compressed at a compression rate of approximately 50%. The width W1 of the effective contact area 91a of the test mold 90 that actually contacted the films 1 to 3 when the films were compressed and the inclination angle θ with respect to the lateral direction at both the left and right ends of the effective contact area 91a in the lateral direction were estimated from the contact position between the mold and the film, and it was confirmed whether or not mountain folds 30 were formed in the films 1 to 3 after compression. Specific experimental conditions are as follows:

[Experimental conditions]
Tip width of tip portion 92: 0 mm, 0.5 mm, 1 mm, 2 mm, 4 mm
R (radius of curvature) of tip 92: 64.9 mm
Shoulder 93 radius of curvature: 2 mm, 4 mm, 8 mm
Film 1: A laminated film having, from the first layer 21 side, 15 μm nylon (NY), 12 μm aluminum vapor-deposited barrier film (VMPET), and 120 μm linear low-density polyethylene (LLDPE). Film 2: A laminated film having, from the first layer 21 side, 12 μm polyethylene terephthalate (PET), 12 μm aluminum foil, 15 μm nylon (NY), and 60 μm linear low-density polyethylene (LLDPE). Film 3: A laminated film having, from the first layer 21 side, 12 μm polyethylene terephthalate (PET), 12 μm aluminum vapor-deposited barrier film (VMPET), and 80 μm linear low-density polyethylene (LLDPE). A method for checking the mountain fold 30: Using a vacuum generator (VUH07-66A manufactured by PISCO), the compressed films 1 to 3 were sucked against a flat suction surface (more precisely, a flat suction surface with a plurality of suction holes formed thereon) under a vacuum condition of about 1.57 g/ ^cm2 , and the width in the lateral direction of the region of the films 1 to 3 that bulged away from the flat suction surface was measured. If the ratio of the width of the bulged region of the films 1 to 3 to the width W1 of the effective contact area 91a was 150% or more, the test result was judged to be "○ (the mountain fold 30 was formed)". Note that the "× (CS)" in the test result shown in FIG. 8 indicates that although a phenomenon occurred in which a part of the films 1 to 3 protruded toward the first layer 21 side, the ratio of the width of the bulged region of the films 1 to 3 to the width W1 of the effective contact area 91a was less than 150%.

From the test results of this experimental example shown in Figure 8, it was confirmed that the mountain fold portion 30 is formed well when the width W1 of the effective contact area 91a is 1 mm to 3.5 mm and the inclination angle θ is 147° or more.

Although an embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design modifications can be made without departing from the present invention as described in the claims.

For example, in the above-described embodiment, the film molding is described as a pouch 10, but the specific form of the film molding may be any form having a film 20 as part of its constituent elements.
In addition, in the above-described embodiment, the pouch 10 has been described as a standing pouch, but the specific form of the pouch 10 may be any form, such as a so-called horizontal gusset pouch in which gusset portions are formed on both sides of the pouch 10, or a so-called flat pouch in which no gusset portions are formed.
In the above-described embodiment, the mountain folds 30 and the valley folds 40 are described as being formed in each film 20, but the positions at which the mountain folds 30 and the valley folds 40 are formed may be any positions. For example, the mountain folds 30 and the valley folds 40 may be formed in only one of the front and back films 20, or the mountain folds 30 and the valley folds 40 may be formed in a gusset film (not shown).
In addition, in the above-described embodiment, both the mountain fold portion 30 and the valley fold portion 40 are formed in the same film 20, but only the mountain fold portion 30 or the valley fold portion 40 may be formed in the film 20 or the gusset film (not shown).
In addition, in the above-described embodiment, a plurality of mountain folds 30 are formed in the film 20, but the number of mountain folds 30 may be one or more, and if a valley fold 40 is formed, the number of valley folds 40 may also be one or more.
In the above embodiment, the three-dimensional shape formed by combining the multiple mountain folds 30 and the multiple valley folds 40 is described as being a diamond cut shape, but the three-dimensional shape may be determined arbitrarily.

In addition, in the above-described embodiment, the film 20 has been described as being formed by bonding together only two layers, the first layer 21 and the second layer 22. However, other layers (such as a metal layer made of aluminum or the like, a layer made of another stretched resin film, etc.) may be provided between the first layer 21 and the second layer 22 or on the outside of the first layer 21 or the second layer 22.
In addition, in the above-described embodiment, the mountain fold portions 30 and the valley fold portions 40 are formed mainly for the purpose of decorating the pouch 10, improving the strength of the film 20 (improving the maintenance of the three-dimensionality of the pouch 10), and imparting functionality to the pouch 10; however, the purpose of forming the mountain fold portions 30 and the valley fold portions 40 may be any purpose, such as providing letters, Braille processing, anti-slip properties, etc.

In addition, in the above-described embodiment, the mountain fold convex portion 60 and the valley fold convex portion 70 are described as being formed on the same surface of the same compression mold 50, but the mountain fold convex portion 60 and the valley fold convex portion 70 may be formed on different compression molds 50. In this case, the process of forming the valley fold portion 40 using the valley fold convex portion 70 may be performed before or after the process of forming the mountain fold portion 30 using the mountain fold convex portion 60.
In the above embodiment, the mountain folding compression surface 61 is described as being composed of a convex curved surface formed with a single R (radius of curvature). However, the specific form of the mountain folding compression surface 61 may be any, and may be composed of only a combination of flat surfaces (straight lines when viewed in cross section) without a curved surface. For example, as shown in FIG. 6(a), it may be a shape that forms a part of a dodecagon. In addition, when it has a curved surface, the mountain folding compression surface 61 may be composed of a combination of a convex curved surface and a flat surface (i.e., a flat surface that extends in a straight line when the mountain folding convex portion 60 is viewed in cross section). For example, as shown in FIG. 6(b), the bottom surface of the compression surface may be a straight line. However, the width of the straight line portion needs to be appropriately set because if it is too large, the mountain folding portion 30 will not be formed.
In addition, it is preferable to form the mountain folding compression surface 61 so that the convex curved surface curved within an imaginary plane perpendicular to the longitudinal direction of the mountain folding convex portion 60 is included at least on both the left and right ends of the mountain folding effective contact area 61a.
In addition, the mountain folding compression surface 61 may be configured by combining a plurality of convex curved surfaces having different R (radius of curvature), or the convex curved surface may be formed so that its radius of curvature changes continuously. In this case, it is preferable to configure the entire mountain folding compression surface 61 (mountain folding contact effective area 61a) as a smooth surface without corners.
In addition, in the above-described embodiment, the valley fold convex portion 70 has been described as a rectangular parallelepiped convex portion, but the specific form of the valley fold convex portion 70 may be any. For example, similar to the mountain fold convex portion 60, the valley fold convex portion 70 may be formed so that the valley fold compression surface 71 includes at least one convex curved surface.
In addition, in the above-described embodiment, the mountain fold portion 30, the valley fold portion 40, the mountain fold convex portion 60, and the valley fold convex portion 70 are described as being formed to extend in a straight line, but the specific aspects of these portions 30, 40, 60, and 70 are not limited to this and may be any, such as extending in a curved line or being formed by a combination of straight lines and curves.

10 ... Pouch (film molded body)
DESCRIPTION OF SYMBOLS 20: Film 20a: First surface 20b: Second surface 21: First layer 22: Second layer 30: Mountain fold portion 31: Processing mark 40: Valley fold portion 41: Valley-shaped fold line 50: Compression die 60: Mountain fold protrusion 61: Mountain fold compression surface 61a: Mountain fold effective contact area 70: Valley fold protrusion 71: Valley fold compression surface 71a: Valley fold effective contact area 71b: Corner portion 80: Anvil

Claims (13)

A method for three-dimensionally processing a film, comprising: cold compressing a film having a first layer and a second layer having a greater elongation than the first layer in a thickness direction using a compression mold to perform three-dimensional processing on the film,
The compression mold includes a mountain folding convex portion having a mountain folding compression surface including a mountain folding effective contact area that actually contacts the film compressed area of the film when the film is compressed,
The width of the mountain folding contact effective region in the horizontal direction perpendicular to the longitudinal direction of the mountain folding convex portion is 1.0 mm to 3.5 mm, the inclination angle with respect to the horizontal direction at both left and right ends of the mountain folding contact effective region is 147° or more, and the compression molding ratio of the film by the mountain folding convex portion is 20% or more of the thickness of the film. The film is then compressed in a cold state by the mountain folding convex portion, so that the film is extended toward the first layer side to form a mountain fold curved in the film.
The mountain fold portion is a portion in which, when the film is adsorbed against a flat surface under any vacuum condition in the range of 1.5 to 4.5 g/ ^cm2 , the width in the lateral direction of the region that bulges away from the flat surface is 150% or more of the width in the lateral direction of the effective contact region for mountain fold. The three-dimensional processing method according to claim 1, characterized in that the mountain folding compression surface includes a convex curved surface curved in an imaginary plane perpendicular to the longitudinal direction of the mountain folding convex portion, at least on both the left and right ends of the mountain folding contact effective area. The three-dimensional processing method according to claim 2, characterized in that the entire effective contact area for mountain folding is composed of the convex curved surface. The three-dimensional processing method according to claim 2 or 3, characterized in that the radius of curvature R of the convex curved surface is set to 1 to 20 mm. The three-dimensional processing method according to any one of claims 1 to 4, characterized in that the entire effective contact area for mountain folding is composed of a smooth surface without corners. The three-dimensional processing method according to any one of claims 1 to 5, characterized in that the surface roughness (Ra) of the effective contact area for mountain folding is 2 μm or less. The film includes a second film compressed region that is subjected to compression molding by a valley fold protrusion,
the valley folding protrusion has a valley folding compression surface including a valley folding effective contact area that actually contacts the second film compressed area when the film is compressed,
The three-dimensional processing method according to any one of claims 1 to 6, characterized in that the width of the effective contact area for valley folding in a horizontal direction perpendicular to the longitudinal direction of the valley folding convex portion is less than 1.0 mm, and the compression molding ratio of the film by the valley folding convex portion is 20% or more of the thickness of the film, thereby forming a valley fold in which the compressed area of the second film is recessed toward the second layer side of the film by cold compressing the compressed area of the second film with the valley folding convex portion. The three-dimensional processing method according to claim 7, characterized in that the mountain fold convex portion and the valley fold convex portion are formed in the same compression mold. A compression mold for subjecting a film having a first layer and a second layer having a larger elongation than the first layer to a three-dimensional processing by cold compressing the film in a thickness direction,
The compression mold includes a mountain folding protrusion for forming a mountain-shaped curved mountain fold portion in the film by cold compressing the compressed region of the film to cause the film to protrude toward the first layer side,
The mountain folding convex portion has a mountain folding compression surface including a mountain folding effective contact area that actually contacts the film compressed area of the film when the film is compressed,
The surface roughness (Ra) of the mountain folding contact effective area is 2 μm or less,
The mountain folding compression surface is formed so that the width of the mountain folding contact effective area in the horizontal direction perpendicular to the longitudinal direction of the mountain folding convex portion is 1.0 mm to 3.5 mm, and the inclination angle with respect to the horizontal direction at both left and right ends of the mountain folding contact effective area is 147° or more. The compression mold further includes a valley folding protrusion for forming a valley fold by cold compressing the second film compressed region of the film, the valley fold being recessed in the second film compressed region toward the second layer side,
the valley folding protrusion has a valley folding compression surface including a valley folding effective contact area that actually contacts the second film compressed area when the film is compressed,
The compression mold according to claim 9, characterized in that the valley fold compression surface is formed so that the width of the valley fold effective contact area in a horizontal direction perpendicular to the longitudinal direction of the valley fold protrusion is less than 1.0 mm. A film having mountain folds and valley folds formed therein,
The laminated film is formed having a first layer and a second layer having a greater elongation than the first layer,
The mountain fold portion has a cross-sectional shape that protrudes toward the first layer side and is curved in a mountain shape,
The valley fold portion has a cross-sectional shape recessed in a valley shape toward the second layer side,
The mountain fold portion has processing marks extending along the longitudinal direction of the mountain fold portion at its middle portion on both left and right sides of its apex,
The distance between the left and right processed marks in the lateral direction perpendicular to the longitudinal direction is 1.0 mm or more and 3.5 mm or less ,
The valley fold portion has two valley-shaped fold lines extending along the longitudinal direction thereof and bent so as to be recessed toward the second layer side,
A film characterized in that the distance between the two valley-shaped fold lines is set to less than 1.0 mm . The film according to claim 11, characterized in that the mountain fold portion is a portion in which, when the film is sucked against a flat surface under any vacuum condition in the range of 1.5 to 4.5 g/ ^cm2 , the width in the lateral direction of the region that bulges away from the flat surface is 150% or more of the distance between the left and right processing marks in the lateral direction. A film molded body having the film according to claim 11 or 12 ,
The film molded body is characterized in that the film has a three-dimensional shape formed by combining a plurality of the mountain folds and a plurality of the valley folds.

Images