JP2021120184A - Container and manufacturing method therefor - Google Patents

Abstract

To provide a manufacturing method for a container, which is less likely to cause damage to printed characters and can simplify a molding process of the container.SOLUTION: A manufacturing method for a container includes: a printing process in which at least one character, graphic or symbol (8) is printed on one side of a printing film (6); a process of preparing a base film (4); a process of laminating the printing film and the base film so that a surface of the printing film on which at least one character, graphic or symbol is printed faces the base film to form a composite film; and a molding process in which the composite film is deformed using a molding machine to mold a container having a three-dimensional shape. Based on a distribution of a direction and an amount of deformation that occurs in the composite film in the molding process, at least one character, graphic, or symbol that has been pre-deformed to compensate for this deformation is printed on the printing film in the printing process.SELECTED DRAWING: Figure 1

Description

The present invention relates to a container and a method for producing the same.

As a container for storing contents such as food, a container having a three-dimensional shape such as a tray shape obtained by thermoforming a synthetic resin sheet such as polypropylene is widely used. When such containers are lined up in stores, a sticker with printed letters is affixed to the container to inform consumers of information about the contents of the container (eg, food manufacturer, raw materials, additives, etc.). Physical action from the outside of the container (eg, rubbing, scratching, etc.) can cause such seals to peel off, and the letters can be blurred and invisible.

An in-mold label molding technique is known as one of the means for solving such a problem (see, for example, Patent Document 1). In in-mold label molding, a preform (which becomes the container body) is introduced into the molding mold with the label set on the inner surface of the molding mold, and the preform is blown into the molding mold. It is deformed to imitate the surface, and at this time, the heated label and the preform are integrated. The label provided in this way is difficult to peel off from the preform (container body). In addition, by printing on the surface of the label facing the preform, it is possible to prevent the printed characters from being damaged by the physical action from the outside of the container. However, in in-mold label molding, the label must be set in the molding mold in advance before molding, the process is complicated, and a dedicated production line is required.

Japanese Unexamined Patent Publication No. 2004-136486

An object of the present invention is to provide a container and a method for producing the same, which are less likely to cause damage to printed characters and can simplify the molding process of the container.

According to one embodiment of the present invention, there is a method for manufacturing a container, in which a printing step of printing at least one character, a figure or a symbol on one surface of a printing film, a step of preparing a base film, and a step of preparing a base film. The printing film and the base film are laminated so that the surface of the printing film on which at least one character, figure or symbol is printed faces the base film to form a composite film. It comprises a step and a molding step of deforming the composite film using a molding machine to form a container having a three-dimensional shape, based on the distribution of the direction and amount of deformation occurring in the composite film in the molding step. Provided is a method for manufacturing a container, characterized in that at least one character, figure or symbol deformed in advance so as to compensate for the deformation is printed on the printing film in the printing step.

According to the above embodiment, since the container is molded from one material (composite film), the molding process can be simplified (compared to the case of using two separate materials such as in-mold label molding). do it). In the molding process, not only the base film but also the printing film on which at least one character, graphic, or symbol (hereinafter, also referred to as “character, etc.”) is printed is relatively significantly distorted (for example, as compared with in-mold label molding). ) As a result, the problem of deformation of characters and the like can be solved by printing the characters and the like deformed in advance on the printing film so that the deformation is compensated for. Further, since the printing film and the base film are laminated so that the surface of the printing film on which the characters and the like are printed faces the base film, damage to the characters and the like can be prevented.

According to another embodiment of the present invention, the container has a three-dimensional shape formed by a composite film including a base film layer and a printing film layer laminated on the base film layer. At least one character, figure, or symbol is printed on the surface of the printing film layer facing the base film layer, and all parts of the composite film are the base film layer and the printing film layer. A container is provided that has. This container can be manufactured by the above-mentioned manufacturing method. This container differs from a container manufactured by in-mold label molding in that all parts of the composite film have a base film layer and a printing film layer.

It is the schematic sectional drawing of the container which concerns on one Embodiment. It is schematic cross-sectional view explaining an example of the manufacturing method of a composite film. It is the schematic explaining the lamination of the base film and the printing film. It is a schematic side view which shows the whole structure of the apparatus for forming a container. It is the schematic explaining the plug assist molding. It is a figure explaining the method of determining the shape of the character deformed in advance. It is a figure explaining the method of determining the shape of the character deformed in advance.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

As schematically shown in FIG. 1, the container 1 is formed by giving the composite film 2 a three-dimensional shape using a resin molding technique known per se. The container 1 can be, for example, in the shape of a rectangular or square thin box in a plan view, but is not limited thereto.

The composite film 2 includes a base film layer 4 (also referred to as "base film 4" before lamination) and a printing film layer 6 laminated on the base film layer 4 (also referred to as "printing film 6" before lamination). Call) and. A printing layer 8 is provided between the base film layer 4 and the printing film layer 6.

Examples of the material constituting the base film layer 4 include PP (polypropylene) containing a filler. The filler improves the rigidity of the container 1. Examples of the filler include talc filler. The grade of PP can be determined according to the usage environment of the container 1. If the container 1 is a frozen food container, cold-resistant grade PP can be used. The thickness of the base film layer 4 can be, for example, about 700 μm (not limited to this).

Examples of the material constituting the printing film layer 6 include CPP (unstretched polypropylene). The printing layer 8 is formed on the surface 7 of the printing film layer 6 facing the base film layer 4. The print layer 8 can be formed by, for example, gravure printing. The thickness of the printing film layer 6 can be, for example, about 25 μm (not limited to this).

As shown in FIG. 1, the base film layer 4 constitutes the inner surface of the container 1 (the surface facing the storage space 5), and the printing film layer 6 constitutes the outer surface of the container 1. In the composite film 2, the printing layer 8 is located between the base film layer 4 and the printing film layer 6. That is, the printing layer 8 is protected by both the base film layer 4 and the printing film layer 6. In particular, the possibility that the print layer 8 is damaged by a physical action (for example, rubbing, scratching, etc.) from the outside of the container 1 is very low. The PP containing the filler constituting the base film layer 4 is opaque, but the CPP constituting the printing film layer 6 is transparent, so that the characters formed by the printing layer 8 are visible from the outside of the container 1. be able to.

The characters formed by the print layer 8 may, for example, display information about the contents of the container 1. When the contents of the container 1 are foods, the information about the contents may include, for example, a food manufacturer, a food seller, a food ingredient, and the like. In the embodiment shown in FIG. 1, since the print layer 8 is provided in the region corresponding to the bottom surface 1B of the container 1, when the bottom surface 1B is viewed from the lower side of FIG. 1, the characters formed by the print layer 8 are visually recognized. be able to.

The manufacturing method of the container 1 will be described below.

The print layer 8 is formed on the print film 6 (print film layer) by a known printing technique, for example, gravure printing (see also FIG. 3A) (printing step). The illustration of the printing process is omitted. The shape of the characters formed by the print layer 8 will be described in detail later.

The printing film 6 on which the printing layer 8 is formed is laminated on the base film 4 (base film layer). In one preferred embodiment, as schematically shown in FIG. 2, the substrate film 4 is formed by extruding a known film manufacturing technique, eg, a molten resin material, from a T-die 10 and immediately after extruding ( (Before cooling), it is pressed against the printing film 6 at the cooling drum 12 and the nip roll 14. As a result, the printing film 6 is laminated on the base film 4, and the composite film 2 is formed (see also FIG. 3B).

Although not shown, a production line may be constructed to perform gravure printing and drying on the printing film 6 while the printing film 6 is being sent from the original roll to the cooling drum 12 and the nip roll 14. ..

FIG. 4 is a schematic view showing a molding apparatus 20 for manufacturing a container 1 from a composite film 2. The composite film 2 is sent to the heater zone 23 via the sheet receiving box 22 from the raw fabric hook 21 on which the raw fabric roll (roll of the composite film 2) is set, and is heated. At this time, after the composite film 2 is drawn down by heat, the composite film 2 is once stretched back, and then at the timing when the drawdown occurs again, the composite film 2 is moved from the heater zone 23 to the vacuum forming machine 24 (here). Then, it is sent to a plug-assist molding machine 24), where it is molded into a three-dimensional shape in the shape of a container 1. After that, the molded composite film 2 is sent to the trimming press machine 25, and the individual containers 1 are separated. The container 1 is dispensed to the product table 26, where the operator visually inspects the appearance. After that, the container 1 is sent to the packaging machine 27, packaged there, and further passed through the metal detector 28 to be inspected for the inclusion of metal foreign matter.

5 (a) to 5 (c) are views showing briefly about molding (molding step) in the plug-assist molding machine 24. The composite film 2 above the mold 24A of the plug-assist molding machine 24 is pushed into the mold 24A (cavity) by the plug 24B (see (a) to (b) of FIG. 5), and the composite film is in this state. By vacuum-adsorbing (VAC) the 2 onto the surface of the mold 24A, the composite film 2 is formed into a shape that resembles the surface of the mold 24A. After that, as shown in FIG. 5 (c), the plug 24B is raised, the vacuum suction is released, and the mold 24A is further lowered (not shown), so that the portion 1A to be the container 1 is removed from the mold 24A. When molding the container 1 with the plug assist molding machine 24, the wall thickness (sheet thickness) left on the side surface or bottom surface of the molded product can be changed by changing the shape of the plug and the timing of applying the plug to the sheet. Can be done.

When the composite film 2 tries to imitate the surface of the mold 24A during molding, the composite film 2 is pulled non-uniformly. The characters (printing layer 8) printed on the printing film 6 are unevenly deformed. The mode of deformation is affected by the overall shape of the container 1, the arrangement of reinforcing ribs, irregularities, etc. (not shown) formed on the bottom surface 1B of the container 1, and the like. If the characters are deformed unevenly, it becomes difficult to recognize the characters.

In order to solve this problem, in the present embodiment, characters that have been deformed in advance so as to compensate for the deformation are printed in the printing process based on the distribution of the direction and amount of deformation that occurs in the composite film 2 in the molding process. It is supposed to be.

Regarding the distribution of the direction and amount of deformation that occurs in the composite film 2 in the molding process, for example, the composite film 2 obtained by laminating the printing film 6 on which the squares are printed on the base film 4 is subjected to the plug-assist molding machine 24. It can be measured by performing a molding experiment of molding into the shape of the container 1.

FIG. 6 is a diagram obtained by extracting a part of the grid, and the distance between the vertical and horizontal lines of the grid can be set to, for example, 1 mm (not limited to this). Set an XY Cartesian coordinate system with the horizontal axis of the grid as the X axis and the vertical axis of the grid as the Y axis, and set the origin O (coordinates (0, 0,) at an appropriate position on the bottom surface 1B of the container 1 (for example, the center of the bottom surface 1B). 0)) is defined. “○” (white circle) in FIG. 6 indicates the position of the grid points of the grid on the bottom surface 1B of the container 1 after molding, assuming that the bottom surface 1B of the container 1 is not deformed due to molding. ing. “●” (black circle) in FIG. 6 indicates the position of the grid points of the grid on the bottom surface 1B of the container 1 after molding when the molding is actually performed. In the present specification, the grid points mean the intersections of the vertical lines and the horizontal lines forming the grid. The orientation and size of the vectors extending from the adjacent pairs of "○" (white circles) to "●" (black circles) indicate the direction and amount of deformation of the composite film 2 in the vicinity of the corresponding grid points. ..

When actually producing the composite film 2 as the material of the container 1 as a product, the pre-deformed characters determined to compensate for the deformation are printed on the printing film 6 based on the above deformation data. (Formation of print layer 8).

"Pre-transformed characters" are
(1) Write characters with the original shape on a distorted grid composed of broken lines connecting "●" (black circles).
(2) After that, by moving the position of "●" (black circle) to the position of the corresponding "○" (white circle), the distorted grid is deformed for each character to make it a grid without distortion.
Can be obtained by
Since a character distorted with respect to the original shape is described on the distortion-free square obtained by the operation (2) above, this becomes a "pre-deformed character".

The "pre-transformed characters" will be described with reference to the simplified model shown in FIG. Assuming that the grid of FIG. 7 (a) is a part of the composite film 2 before molding, this region is doubled in length in the vertical direction as shown in FIG. 7 (b) by molding. It is assumed that it is deformed so as to be, but it is not deformed in the lateral direction. A character "A" having a neat shape to be finally displayed on the deformed grid of FIG. 7B is described. The deformed square of FIG. 7B is not deformed in the horizontal direction, but is deformed so that the length in the vertical direction is halved, and the shape of the square is returned to that before molding. As shown in FIG. 7 (C), by deforming the character "A" according to the deformation of this grid, the "pre-deformed character A" can be obtained.

Due to the deformation of the composite film 2 during molding, the same problem may occur not only in the shape of each character but also in the positional relationship between the characters. That is, for example, there may be a problem that a plurality of characters (character groups) that should normally be arranged at equal intervals on a straight line are arranged in an arch shape or a meandering shape, or the intervals become uneven. Such a problem can also be solved by the same procedure as in (1) and (2) above. In this case, describe the character group having the original arrangement on the distorted grid composed of the broken lines connecting "●" (black circles) (corresponding to (1) above), and then the position of "●" (black circles). By moving the above to the position of the corresponding "○" (white circle) to deform the distorted square to make it a non-distorted square, a "pre-deformed character group" can be obtained (the above ((above). Corresponds to 2)). The "pre-deformed character group" thus obtained may be printed on the printing film 6.

Needless to say, according to the above method, both the distortion of individual characters and the distortion of the arrangement of character groups can be dealt with at the same time.

According to the above embodiment, since the container 1 is molded from one material (composite film 2), the molding process can be simplified as compared with the case where two materials such as in-mold label molding are used. Can be done. In the molding process, not only the base film 4 but also the printing film 6 on which the characters are printed are distorted relatively greatly (compared to, for example, in-mold label molding), so that the deformation of the characters is compensated for. This is solved by printing the characters or character groups that have been deformed in advance on the printing film 6. Further, since the printing film 6 and the base film 4 are laminated so that the surface of the printing film 6 on which the characters are printed faces the base film 4, damage to the characters can be prevented.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the claims.

In the above embodiment, what is printed on the printing film 6 is a character or a character group, but the present invention is not limited to this. What is printed on the printing film 6 may be at least one character, graphic or symbol (also referred to as "character or the like"). By printing the characters or the like deformed in advance on the printing film 6, the characters or the like in the original shape can be displayed on the container 1 after molding.

Further, as the base film 4 constituting the composite film 2, in addition to the above-mentioned PP containing talc filler, for example, PP alone (PP containing no filler) can be used.

The method of laminating the base film 4 and the printing film 6 is not limited to the above, and extruded laminating can be used, for example.

The method of forming the print layer 8 on the printing film 6 is not limited to gravure printing, and for example, flexographic printing can be used.

The method for molding the container 1 from the composite film 2 is not limited to plug-assist molding, and for example, hot plate molding can be used.

1 Container 2 Composite film 4 Base film 6 Printing film 8 Printing layer

Claims (7)

It ’s a container manufacturing method.
A printing process in which at least one character, graphic or symbol is printed on one side of a printing film.
The process of preparing the base film and
The printing film and the base film are laminated to form a composite film so that the surface of the printing film on which at least one character, graphic or symbol is printed faces the base film. Process and
A molding process of deforming the composite film using a molding machine to form a container having a three-dimensional shape, and
With
Based on the distribution of the direction and amount of deformation that occurs in the composite film in the molding step, at least one character, figure, or symbol that has been deformed in advance so as to compensate for the deformation is printed on the printing film in the printing step. A method of manufacturing a container, which comprises printing on. The method for manufacturing a container according to claim 1, wherein the distribution of the direction and amount of deformation occurring in the composite film in the molding step is determined by a molding experiment. The method for manufacturing a container according to claim 2, wherein the molding experiment is performed using a composite film obtained by laminating a printing film on which a grid pattern is printed and a base film. The method for manufacturing a container according to claim 1, wherein after the molding step, the at least one character, figure or symbol is located on the bottom surface of the container. The method for manufacturing a container according to claim 1, wherein the molding step is carried out by using a vacuum molding technique. A container having a three-dimensional shape formed by a composite film including a base film layer and a printing film layer laminated on the base film layer.
At least one character, graphic, or symbol is printed on the surface of the printing film layer facing the base film layer, and all parts of the composite film are the base film layer and the printing film. A container that has a layer. The container according to claim 6, wherein the character is located on the bottom surface of the container.

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