WO2021152851A1

WO2021152851A1 - Method for producing packaging container, and packaging container

Info

Publication number: WO2021152851A1
Application number: PCT/JP2020/003791
Authority: WO
Inventors: 宏紀長谷川
Original assignee: 株式会社エイエムジー
Priority date: 2020-01-31
Filing date: 2020-01-31
Publication date: 2021-08-05
Also published as: JP6851673B1; JPWO2021152851A1

Abstract

The purpose of the present invention is to provide: a method for producing a packaging container by using a paper mold, the packaging container having less environmental impact and hardly absorbing moisture; and a packaging container. A packaging container 1 according to the present invention is produced by means of a substrate 2 in which a thermoplastic resin is distributed in a paper fiber 62, and in the thickness direction of the substrate 2, the thermoplastic resin is distributed relatively more in the surface-side part than in the center-side part of the substrate 2.

Description

Manufacturing method of packaging container and packaging container

The present invention relates to a method for manufacturing a packaging container for packaging a container containing cosmetics such as mascara, and a packaging container.

In recent years, as a packaging container, in addition to mechanical strength, it is required to have a small burden on the environment. In order to meet such a demand, a technique called paper mold (also referred to as pulp mold) in which fibers obtained by melting paper are molded into a desired shape is used (for example, Patent Document 1).

JP-A-2018-199872

In the present specification, "paper mold" is used to mean a method for producing a paper molded product, which includes a step of dispersing plant fibers in a liquid and making it with a wire mesh and a drying step. And, "molded article" is used as meaning the paper molded article produced by a paper mold. Further, "hygroscopicity" means a property that a substance absorbs water, and "high hygroscopicity" means that a substance easily absorbs water. Then, "hygroscopicity" means a property that the substance does not easily absorb water, and "high hygroscopicity" means that the substance does not easily absorb water.

Paper mold does not use petroleum-derived raw materials, so it has the advantage of having a small impact on the environment. On the other hand, the molded product produced by the paper mold easily absorbs moisture. That is, there is a disadvantageous property that the molded product has high hygroscopicity. When the molded product absorbs water and then the absorbed water evaporates, the molded product does not return to the original shape but is deformed.

Based on the above, the present invention provides a method for manufacturing a packaging container using a paper mold and a packaging container, which has a small environmental load and does not easily absorb water.

The first invention is a mixed liquid in which a paper and a resin fiber composed of a thermoplastic resin are put into a predetermined liquid to generate a mixed liquid containing the paper fiber constituting the paper and the resin fiber. By arranging the first mold member in which the net-like member having a plurality of through holes is arranged in the generation step and the mixed liquid and sucking the mixed liquid in the direction toward the first mold member, the net-like shape is formed. Using the first pre-stage product generation step of producing the first pre-stage product in contact with the member, the drying step of drying the first pre-stage product to produce the second pre-stage product, and the second mold member. A molding step of producing a packaging container having a predetermined shape by compression molding while heating the second pre-stage product, and in the molding step, the temperature of the second mold member is set to the heat. The compression ratio (d1), which is the ratio of the thickness (d1) of the second pre-stage product to the thickness (d2) of the packaging container, is set to a reference temperature (temp1) in a predetermined temperature range higher than the melting point of the plastic resin. d1 / d2) is set to a predetermined reference compression ratio (n1), the execution time of the molding step is set to a predetermined reference time (t1), and the reference compression ratio (n1) and the reference time (t1) are for the packaging. A packaging container in which the ratio of the thermoplastic resin to the paper fiber in the container is defined to be relatively large in the surface side portion with respect to the center side portion in the thickness direction of the packaging container. It is a manufacturing method of.

The purpose of using resin in paper molds is generally to increase the mechanical strength of the molded product (hereinafter referred to as "normal purpose"). From the viewpoint of the general purpose, it is desirable that the resin is uniformly distributed inside the molded product, so that manufacturing conditions such that the resin is uniformly distributed are required. Hereinafter, the standard manufacturing conditions for paper molds for normal purposes are referred to as "standard conditions". If the amount of resin in the molded product is too small, the increase in mechanical strength will be insufficient. For this reason, the amount of resin is increased, but this loses the advantage of the paper mold that the load on the environment is small. On the other hand, the inventor of the present invention has developed a technique for improving the moisture absorption resistance of a molded product while suppressing the amount of resin from the viewpoint of environmental protection for the purpose of improving the moisture absorption resistance. .. As a result, the central portion in the thickness direction of the packaging container as a molded product (the thickness direction of the base material of the packaging container. The same applies hereinafter. The "thickness direction of the second pre-stage product" has the same meaning). On the other hand, we came up with a technique to distribute a relatively large amount of resin in the region on the surface side. This technique is a technique originally developed by the inventor of the present invention, and is hereinafter referred to as "surface diffusion". Surface diffusion focuses on the property that the thermoplastic resin melts and becomes a fluid when heated, but the paper fiber does not become a fluid even when heated, and the thermoplastic resin flows between the paper fibers. It controls the behavior (hereinafter referred to as "flow control"). Specifically, as in the configuration of the first invention, the molten resin is moved to the surface side of the second pre-stage product by applying a predetermined reference compression ratio when compressing the second pre-stage product while heating. Further, by applying a predetermined reference time, the behavior of the resin that has moved to the surface side of the second pre-stage product and returns to the center side is suppressed. From the experiment of the inventor of the present invention, it was found that the resin located on the center side in the thickness direction of the packaging container has a small contribution to the improvement of hygroscopicity. According to the configuration of the first invention, since a relatively large amount of resin can be distributed on the surface side of the packaging container, a relatively small amount of resin is sufficient for improving hygroscopicity. As a result, it is possible to manufacture a packaging container using a paper mold, which has a small burden on the environment and does not easily absorb water. The second pre-stage product is deformed in the process of the molding process and finally reaches the packaging container, but the state of being deformed to reach the packaging container after the molding process is started is also "second pre-stage product". Called "goods".

In the second invention, in the configuration of the first invention, the reference compression ratio (n1) is such that the molten thermoplastic resin is effectively moved to the surface side of the second pre-stage product of the paper mold. It is a method for manufacturing a packaging container, which is defined as a compression ratio larger than the compression ratio under the standard conditions, which is a standard manufacturing condition.

The inventor of the present invention controls the flow of the molten resin to the surface side of the second pre-stage product when the compression ratio when compressing the second pre-stage product to form a packaging container is a standard condition. We found that it could not be implemented effectively. It is considered that this is because when the compression ratio is small, the force for pushing the resin distributed in the central portion in the thickness direction of the second pre-stage product to the surface side is insufficient. In this regard, according to the configuration of the second invention, the reference compression ratio (n1) is defined as a compression ratio larger than the compression ratio under the standard conditions, which is the standard manufacturing condition of the paper mold. The flow control for moving the second pre-stage product to the surface side can be effectively implemented.

According to the third invention, in the configuration of the first invention, the thermoplastic resin in a molten state is placed on the surface of the second pre-stage product in the thickness direction of the second pre-stage product during the reference time (t1). A packaging container specified as a time shorter than the compression time under the standard conditions, which are the standard manufacturing conditions for paper molds, in order to suppress the behavior of returning to the center side of the second pre-stage product after moving to the side. It is a manufacturing method of.

According to the inventor of the present invention, when the time for compressing the second pre-stage product while heating (compression time) is the time under the standard conditions, the molten thermoplastic resin is once placed on the surface side of the second pre-stage product. We found that there was a behavior of returning to the center side after moving to, and came up with the idea that flow control that suppresses this behavior is useful for surface diffusion. According to the configuration of the third invention, the reference time (t1) is defined as a time shorter than the compression time under the standard conditions which are the standard manufacturing conditions of the paper mold. It is possible to limit the behavior of the moved resin returning to the center side.

In the fourth invention, in the configuration of the first invention, the reference compression ratio (n1) is defined as a compression ratio larger than the standard compression ratio in the paper mold, and the reference time (t1) is the paper. A method of manufacturing a packaging container, which is defined as a shorter time than the standard time in a mold.

The inventor of the present invention carries out the molding step as a condition for realizing the flow control for carrying out surface diffusion, at a compression ratio larger than the compression ratio under the standard condition and in a shorter time than the time under the standard condition. I found that it was beneficial. By extruding the molten thermoplastic resin to the surface side of the first pre-stage product with a large compression ratio and performing the molding process in a short time, the state in which the resin is relatively largely distributed on the surface side is maintained. Is thought to be possible. Further, since the density of the molded product can be increased by the large compression ratio, the mechanical strength of the molded product can be ensured even when the amount of resin is smaller than the amount of resin under the standard conditions. can. According to the configuration of the fourth invention, the reference compression ratio (n1) is defined as a compression ratio larger than the standard compression ratio by the paper mold, and the reference time (t1) uses the resin fiber in the paper mold. Since the time is specified as shorter than the standard time, the effect of surface diffusion can be sufficiently exerted while ensuring the mechanical strength.

In the fifth aspect of the invention, in the configuration of the first invention, in the mixed solution, the ratio (w2 / w1) of the weight (w2) of the resin fiber to the weight (w1) of the paper fiber is standard in the paper mold. The method for manufacturing a packaging container according to claim 1, which is a standard ratio (m1) defined in a range smaller than the above ratio.

According to surface diffusion, in a molded product, a relatively large amount of resin can be distributed on the surface and in the vicinity of the surface rather than on the center side. As a result, it is possible to prevent moisture from entering the inside of the molded product from the outside. That is, since the resin is not uniformly distributed over the entire molded product but a large amount of resin is distributed on the surface side, the amount of resin can be made smaller than the amount under the standard conditions. This means that the burden on the environment is small. In this regard, according to the configuration of the fifth invention, in the mixed solution, the ratio (w2 / w1) of the weight of the resin fiber (w2) to the weight of the paper fiber (w1) is higher than the standard ratio in the paper mold. Since it is specified as a small ratio, it is possible to exert the effect of surface diffusion while reducing the load on the environment.

The sixth invention is a packaging container produced by a base material in which a thermoplastic resin is distributed in paper fibers, and the thermoplastic resin is located on the center side of the base material in the thickness direction of the base material. It is a packaging container that is relatively abundantly distributed in the portion on the surface side of the base material with respect to the portion of the base material.

According to the present invention, it is possible to provide a method for manufacturing a packaging container using a paper mold and a packaging container that have a small impact on the environment and do not easily absorb water.

It is the schematic perspective view which looked at the packaging container which concerns on embodiment of this invention from the front side. It is a schematic perspective view which looked at the packaging container from the back side. It is the schematic which shows the whole manufacturing process. It is the schematic which shows the suction process. It is the schematic which shows the suction process. It is the schematic which shows the suction process. It is a schematic diagram which shows the process of moving from a suction process to a drying process. It is a schematic diagram which shows the molding process. It is a schematic diagram which shows the molding process. It is a schematic diagram which shows the molding process. It is a schematic diagram which shows the molding process. It is a schematic diagram which shows the molding process. It is a conceptual diagram which shows the internal state of the 2nd pre-stage product. It is a conceptual diagram which shows the internal state of the 2nd pre-stage product in the intermediate stage of a molding process. It is a conceptual diagram which shows the internal state of the 2nd pre-stage product in the intermediate stage of a molding process. It is a conceptual diagram which shows the internal state of the 2nd pre-stage product in the final stage of a molding process. It is a schematic flowchart which shows the manufacturing method of a packaging container. It is a figure which shows the experimental result. It is a figure which shows the surface of the implementation product of the second pre-stage product. It is a figure which shows the cross section of the implementation product of the 2nd pre-stage product. It is a figure which shows the surface of the implementation product of a packaging container. It is a figure which shows the cross section of the product of the packaging container. It is a conceptual diagram for demonstrating the moisture absorption resistance of a packaging container. It is a conceptual diagram which shows the adhesiveness of a packaging container with a plastic film. It is a conceptual diagram which shows the adhesiveness with the aluminum foil of a packaging container.

Hereinafter, embodiments for carrying out the present invention (hereinafter, embodiments) will be described in detail. In the following description, the same components will be designated by the same reference numerals, and the description thereof will be omitted or abbreviated. The description of the configuration that can be appropriately implemented by those skilled in the art will be omitted, and only the basic configuration of the present invention will be described.

<Structure of packaging container>
As shown in FIGS. 1 and 2, the packaging container 1 (hereinafter referred to as “container 1”) is generated by the base material 2. The container 1 is manufactured by a paper mold using a thermoplastic resin. Container 1 is an example of a packaging container.

The base material 2 is composed of a thermoplastic resin (hereinafter, also simply referred to as “resin”) distributed in paper fibers. The base material 2 is a plate-shaped material having a predetermined thickness, and has a first surface 2a, a second surface 2b, and a side surface 2c. A recessed portion 2d is formed on the base material 2 in order to store the cosmetic container. The depressed portion 2d is concave on the first surface 2a and convex on the second surface 2b. A cosmetic container such as a mascara container is arranged in the recessed portion 2d on the first surface 2a side. After that, the plastic film is welded to the entire surface except the recessed portion 2d of the first surface 2a. A metal foil cut into a shape such as a manufacturer's logo is welded to the second surface 2b side. The metal foil is, for example, an aluminum foil. In the present embodiment, the first surface 2a and the second surface 2b are referred to as "surfaces" of the base material 2. The area between the first surface 2a and the second surface 2b is referred to as the "inside" of the base material 2. The center positions of the first surface 2a and the second surface 2b in the thickness direction of the base material 2 are referred to as "centers" of the base material 2. As a relative concept, the region including the center is called the "central region", and the region closer to the surface with respect to the "central region" is called the "surface side region". In the present specification, the "surface", "inside" or "center" of the container 1 is synonymous with the "surface", "inside" and "center" of the base material 2. This also applies to the surface, inside, or center of the first pre-stage product 1A and the second pre-stage product 1B, which will be described later, respectively, and the base material (plate-like material) and the first pre-stage product 1A of the first pre-stage product 1A, respectively. (Ii) It means the surface, inside or center of the base material (plate-shaped material) of the first-stage product 1B.

The container 1 has a technique (surface diffusion) in which a relatively large amount of resin is distributed on the surface and in the vicinity of the surface (hereinafter, also referred to as “surface side”) as compared with the central portion in the thickness direction of the base material 2. Manufactured by. As a result, in the thickness direction of the base material 2, the thermoplastic resin is distributed in a relatively large amount in the portion on the surface side with respect to the portion on the center side.

<Outline of the manufacturing process of packaging containers>
As described above, the standard manufacturing conditions of the paper mold when the resin is used for the purpose of increasing the mechanical strength of the molded product are referred to as "standard conditions". In the present embodiment, the resin fiber is not used for the purpose of increasing the mechanical strength of the molded product, but is used for improving the moisture absorption resistance. In this embodiment, the mechanical strength is realized by a compression ratio larger than the standard condition, as will be described later. In the present embodiment, the above-mentioned flow control is carried out and surface diffusion is realized by adopting a manufacturing method completely different from the standard conditions. Hereinafter, the outline of the manufacturing process of the container 1 will be described with reference to FIG.

Container 1 is manufactured by the manufacturing system 100. The main components of the manufacturing system 100 are a mixing liquid manufacturing tank 6, a mixing liquid adjusting device 8, a first pre-stage product generating device 10, a drying device 30, and a molding device 20.

The mixed liquid production tank 6 is an apparatus for producing a mixed liquid 60 containing paper fibers and resin fibers by putting paper and resin fibers composed of a thermoplastic resin into a predetermined liquid. The mixture manufacturing tank 6 is an example of a mixture manufacturing means. The treatment performed in the mixture manufacturing tank 6 is an example of the mixture generation step.

In this embodiment, water is used as a predetermined liquid. As the paper, white copy paper is used. The predetermined liquid is not limited to water. The paper is not limited to white copy paper, and for example, colored copy paper, old newspapers, old magazines, corrugated cardboard, and the like may be used. As the resin fiber composed of the thermoplastic resin, for example, a resin fiber composed of a polyolefin-based resin is used, but the present invention is not limited to this. As the resin fiber, for example, a grade of SWP (registered trademark) of Mitsui Chemicals, Inc. called E400 is used. The melting point of E400 is 135 degrees Celsius (° C.).

Water, paper and resin fibers are put into the mixed liquid manufacturing tank 6. When a water stream is generated by the stirring device 7 in this state, the paper is decomposed into paper fibers after a lapse of a predetermined time, and a mixed liquid 60 in which the paper fibers and the resin fibers are substantially uniformly dispersed is generated.

In the mixed solution 60, the ratio (w2 / w1) of the weight (w2) of the resin fiber 64 to the weight (w1) of the paper fiber 62 is a reference ratio (m1) defined in a predetermined range smaller than the ratio under the standard conditions. be. For example, the percentage (w2 / w1) under standard conditions is 20 percent (%) or more and 40 percent or less, while the reference percentage (m1) is defined in the range of 5 percent or more and 12 percent or less. In this embodiment, the reference ratio (m1) is 7%.

The mixed liquid 60 generated in the mixed liquid manufacturing tank 6 is transferred to the mixed liquid adjusting device 8 as shown by the arrow F1. In the mixture liquid adjusting device 8, foreign matter such as metal is removed from the mixture liquid 60. Further, in the mixture liquid adjusting device 8, a predetermined amount of water in the mixed liquid 60 is removed, and the concentration of the mixed liquid 60 is adjusted. The mixture adjusting device 8 is an example of the mixture adjusting means. The process performed in the mixture adjusting device 8 is an example of the mixture adjusting step.

The mixed liquid 60 adjusted by the mixed liquid adjusting device 8 is transferred to the first pre-stage product generating device 10 as shown by an arrow F2. The first pre-stage product generation device 10 is composed of a mixing liquid tank 12 and a suction device 14. The mixed liquid 60 adjusted by the mixed liquid adjusting device 8 is put into the mixed liquid tank 12.

The suction device 14 includes first-

type members

18A and 18B in which a net-like member (not shown) having a plurality of through holes is arranged. When the first mold member 18A is arranged in the mixed liquid 60, the suction device 14 sucks the mixed liquid 60 from above the first mold member 18A and below the mesh member of the first mold member 18A. The first pre-stage product 1A having a predetermined thickness (d0) is produced. The first first-stage product 1A is a product product in which paper fibers and resin fibers are substantially uniformly distributed. The first pre-stage product generating device 10 is an example of the first pre-stage product generating means. The process performed in the first pre-stage product generation device 10 is an example of the first pre-stage product generation step.

The first pre-stage product 1A generated by the first pre-stage product generation device 10 is transferred to the drying device 30 by the transfer device 40. In the drying apparatus 30, the first pre-stage product 1A is dried, the moisture is removed, and the second pre-stage product 1B is produced. The shapes of the first pre-stage product 1A and the second pre-stage product 1B are substantially similar to those of the container 1 shown in FIGS. 1 and 2, and the outer shape thereof is larger than that of the container 1.

The second front stage product 1B is transferred to the molding device 20 by the transfer device 50. In the molding apparatus 20, the container 1 having a predetermined shape is produced by compression molding the second pre-stage product 1B while heating it using the second mold member 22. The molding apparatus 20 is an example of a molding apparatus. The process performed by the molding apparatus 20 is an example of a molding process.

<About the first pre-stage product production process>
Hereinafter, the first pre-stage product production step will be described in detail with reference to FIGS. 4 to 7. As shown in FIGS. 4 to 7, the first pre-stage product generation device 10 includes a mixing liquid tank 12 and a suction device 14. The mixing liquid tank 12 is a container for storing the liquid, and the mixing liquid 60 is stored. As conceptually shown in FIG. 4, the paper fiber 62 and the resin fiber 64 are practically and uniformly dispersed in the mixed liquid 60 in the mixed liquid tank 12.

The suction device 14 is composed of a central member 16,

intermediate members

17A and 17B, and

first mold members

18A and 18B. The suction device 14 is configured to be rotatable in the direction of arrow A1 in FIG. 5 with the central member 16 as a rotation axis. The central member 16 is connected to a vacuum suction device (not shown). The

intermediate members

17A and 17B are hollow members. The

first mold members

18A and 18B are molds for forming a plate-shaped first pre-stage product 1A from the mixed liquid 60. The

first type members

18A and 18B are box-shaped members having an open surface on the side not connected to the

intermediate members

17A and 17B, and the bottom 18a is a net-like member having a large number of through holes (not shown). It is composed of.
The bottom portion 18a has a convex portion. The negative pressure generated by the vacuum suction device acts on the net-like member forming the bottom portion 18a via the central member 16 and the

intermediate members

17A and 17B.

As shown in FIG. 4, in a state where the first mold member 18A is arranged in the mixed liquid 60, the vacuum suction device is operated and the direction toward the first mold member 18A shown by the arrow Z1, that is, upward. When the mixed liquid 60 is sucked, as shown in FIG. 5, the paper fibers 62 and the resin fibers 64 in the mixed liquid 60 are laminated on the surface of the net-like member constituting the bottom portion 18a of the first mold member 18A, and have a thickness d0. As a product, the first pre-stage product 1A is produced. The thickness d0 of the first pre-stage product 1A is, for example, 3.0 mm (mm). The density of the first pre-stage product 1A is, for example, 0.20 g / cubic centimeter (g / cm ³ ).

When the production of the first pre-stage product 1A is completed in the first mold member 18A, the suction device 14 rotates in the direction of arrow A1 as shown in FIG. 5, and the first mold member 18A moves upward as shown in FIG. Change the position. Then, the first mold member 18B is repositioned downward and placed in the mixed liquid 60.

In the state shown in FIG. 6, the first front stage product 1A is held by the holding portion 44 of the transfer device 40. The holding portion 44 of the transfer device 40 is connected to the shaft portion 42. The first front stage product 1A is sucked in the direction of arrow Z1 by a suction mechanism arranged in the shaft portion 42, and is attracted to and held by the holding portion 44 as shown in FIG. As the suction mechanism, a second vacuum suction device may be provided outside the transfer device 40 and connected to the shaft portion 42.

From the state shown in FIG. 7, the shaft portion 42 moves in the horizontal direction indicated by the arrow X1 to transfer the first pre-stage product 1A to the simple drying device 30.

<About the drying process>
The drying process will be described with reference to FIG. The drying device 30 is a box-shaped device including a belt conveyor 32 and a heater (not shown). In a state where the inside of the drying device 30 is adjusted to a predetermined temperature, the first front stage product 1A is placed on the belt conveyor 32 and moved in the direction of arrow X1. Moisture contained in the first pre-stage product 1A evaporates in the process of moving in the direction of arrow X1 in the drying device 30, and the second pre-stage product 1B is produced.

The thickness d1 of the second pre-stage product 1B is, for example, 2.5 mm (mm). The density of the second pre-stage product 1A is, for example, 0.25 g / cubic centimeter (g / cm ³ ).

The second front stage product 1B is transferred to the molding device 20 by the transfer device 50. The configuration of the transfer device 50 is the same as the configuration of the transfer device 40. In the second pre-stage product 1B, the ratio of the weight of the resin fiber to the weight of the paper fiber is not substantially larger in the region on the surface side in the thickness direction than in the central region. That is, in the second pre-stage product 1B, the resin fibers are substantially uniformly distributed in the paper fibers. Alternatively, in the second pre-stage product 1B, the ratio of the weight of the resin fiber to the weight of the paper fiber is smaller in the region on the surface side in the thickness direction than in the central region.

<About the molding process>
Next, the molding process will be described with reference to FIGS. 8 to 12. As shown in FIG. 8, the molding apparatus 20 includes a second mold member 22. The second mold member 22 is composed of an upper mold member 22A and a lower mold member 22B. The upper mold member 22A can move in the vertical direction shown by arrows Z1 and Z2. The upper mold member 22A moves in the vertical direction to open and close the second mold member 22. The upper mold member 22A and the lower mold member 22B are molds for compression molding.

A recess 22a is formed in the upper mold member 22A. In the lower mold member 22B, a convex portion 22b having a shape corresponding to the concave portion 22a is formed. The shapes of the concave portion 22a and the convex portion 22b correspond to the shape of the depressed portion 2d (see FIGS. 1 and 2).

The upper mold member 22A and the lower mold member 22B each have a built-in heater 22c. The heater 22c can generate heat and set the temperature in the cavity generated by the upper mold member 22A and the lower mold member 22B. In the present embodiment, "the temperature of the upper mold member 22A and the lower mold member 22B" means the temperature in this cavity.
The temperature of the upper mold member 22A and the lower mold member 22B is set to a reference temperature (temp1) in a predetermined range higher than the melting point of the resin fiber 64 by adjusting the heater 22c. The reference temperature (temp1) is, for example, a temperature higher than the melting point of the resin fiber 64 based on the melting point, and the degree of the height is in the range of 5 degrees Celsius (° C.) or more and 25 degrees Celsius (° C.) or less. Is regulated. The melting point of the resin fiber 64 is, for example, 135 degrees Celsius (° C.). The temperature in the cavity formed by the upper mold member 22A and the lower mold member 22B is set to, for example, 150 degrees Celsius.

As shown in FIG. 9, the second front stage product 1B is arranged on the lower mold member 22B. Then, the upper mold member 22A is moved downward as shown by the arrow Z2, and as shown in FIGS. 10 and 11, the second front stage product 1B is compressed while being heated. When the second mold member 22 is closed and the cavity composed of the concave portion 22a and the convex portion 22b is closed, the temperature inside the cavity becomes the reference temperature (temp1). In this state, the resin fiber 64 in the second pre-stage product 1B melts, but the paper fiber 62 does not melt. When the resin fiber 64 is melted, it passes between the paper fibers 62 by compression and moves to the surface side of the second pre-stage product 1B. Hereinafter, a resin fiber 64 in a molten state and a state in which the resin fiber 64 is solidified after being melted are referred to as “resin”. In the figure attached to the specification, the code of the resin is shown to be the same as the code of the resin fiber 64.

As shown in FIG. 11, when a predetermined reference time (t1) elapses with the cavity closed, the upper mold member 22A is moved upward as shown by the arrow Z1 as shown in FIG. Then, the second mold member 22 opens, the temperature in the cavity composed of the concave portion 22a and the convex portion 22b decreases, the molten resin gradually solidifies, and the moving speed of the resin in the second pre-stage product 1B decreases. .. When the resin is solidified and the position of the resin is fixed, the container 1 is formed. The state of the second pre-stage product 1B is changed in the molding process, but the changing state of the container 1 from the state before entering the molding process is also referred to as "second pre-stage product 1B".

The thickness (d2) of the container 1 is defined as a predetermined thickness. The thickness of the container 1 is, for example, 1.0 mm (mm). The density of container 1 is, for example, 0.64 grams / cubic centimeter (g / cm ³ ).

The thickness (d2) of the container 1 is defined in relation to the thickness (d1) of the second first stage product 1B. Alternatively, it may be said that the thickness (d1) of the second pre-stage product 1B is defined by the thickness (d2) of the container 1. When the thickness (d2) of the container 1 is determined, the thickness (d1) for making the container 1 into the specifications specified in the present embodiment is the thickness (d1). The thickness d1 of the second pre-stage product 1B is also referred to as "reference thickness d1". Specifically, the compression ratio (d1 / d2), which is the ratio of the thickness (d1) of the second pre-stage product 1B before entering the molding process to the thickness (d2) of the container 1, is a predetermined reference compression ratio. It is defined as (n1).

The reference compression ratio (n1) and the reference time (t1) are set so that the amount of resin in the container 1 is relatively large in the surface side portion with respect to the central portion in the thickness direction of the container 1. Is regulated.

The predetermined reference compression ratio (n1) is also defined as a compression ratio that allows the molten resin to effectively move outward in the thickness direction of the second pre-stage product 1B. The reference time (t1) suppresses the behavior of the molten resin moving to the surface side of the second front stage product 1B in the thickness direction of the second front stage product 1B and then returning to the center side of the second front stage product 1B. It is defined as the time that can be done.

The reference compression ratio (n1) is defined as a compression ratio in a predetermined range larger than the standard compression ratio. The standard compression ratio is, for example, 1.5 to 2.0, while the reference compression ratio (n1) is, for example, 2.5 or more and 5.0 or less. In this embodiment, the reference compression ratio (n1) is 2.5. By setting the reference compression ratio (n1) to a compression ratio larger than the standard compression ratio, the molten resin can be easily moved in the thickness direction of the second pre-stage product 1B, and is finally manufactured. The mechanical strength of the container 1 is also improved. By making the thickness d1 of the second pre-stage product 1B larger than the standard condition and making the reference compression ratio (n1) larger than the standard compression ratio, the density of the container 1 is increased and the mechanical strength is increased. improves. That is, in the container 1, the mechanical strength is secured by the density.

The reference time (t1) is defined as a predetermined range of time shorter than the standard time. For example, the standard time is 10 seconds (second), while the reference time (t1) is defined between 3 and 7 seconds. In this embodiment, the reference time (t1) is 5 seconds. As a result, it is possible to suppress the behavior of the molten resin moving to the surface side of the second pre-stage product 1B and then returning to the center side.

In the above-mentioned reference compression ratio (n1) and reference time (t1), the ratio of the resin to the paper fiber 62 on the surface side in the thickness direction of the container 1 is the paper fiber on the surface side in the thickness direction of the second pre-stage product 1B. It can also be said that it is specified to be larger than the ratio of the resin to 62. Further, in the reference compression ratio (n1) and the reference time (t1), the resin fibers 64 distributed in the central region in the thickness direction of the second pre-stage product 1B are melted, and the resin is in the thickness direction of the second pre-stage product 1B. It can also be specified that the resin moves to the surface side and the resin does not completely return to the central region.

With reference to FIGS. 13 to 16, the internal state of the second pre-stage product 1B from the state before the second pre-stage product 1B enters the molding process to the container 1 will be conceptually described. Before the second pre-stage product 1B enters the molding process, as shown in FIG. 13, the second pre-stage product 1B has a thickness d1 and the resin fiber 64 is substantially uniform in relation to the paper fiber 62. It is distributed in. In this state, the second pre-stage product 1B is compressed while being heated by applying pressure from the vertical direction indicated by arrows P1 and P2 by the mold member 22.

As shown in FIGS. 14 and 15, the resin fiber 64 melts in a step of being compressed from above and below while being heated. On the other hand, the paper fiber 62 does not melt. Therefore, as shown by arrows B1 and B2 in FIG. 15, the molten resin passes between the paper fibers 62 by compression and moves to the surface side of the second pre-stage product 1B. When the mold member 22 is completely closed, as shown in FIG. 16, the second front stage product 1B has a thickness d2. When the reference time (t1) elapses while the mold member 22 is completely closed, the mold member 22 opens and the temperature in the cavity generated by the mold member 22 decreases. Then, the molten resin is solidified to form the container 1. At this time, the solidified resin is distributed in a relatively large amount on the surface side of the container 1 in the thickness direction of the container 1.

<Outline of manufacturing method of container 1>
With reference to FIG. 17, the outline of the above-mentioned manufacturing method of the container 1 will be briefly described again. First, the mixed liquid production tank 6 (FIG. 3) is a mixture of paper and resin fibers so that the ratio (w2 / w1) of the weight of the resin fibers 54 (w2) to the weight (w1) of the paper fibers 62 becomes the reference ratio (m1). (See) (see step ST1 in FIG. 17). Subsequently, the first pre-stage product 1A having a predetermined thickness (d0) is generated (step ST2). Subsequently, the first pre-stage product 1A is dried to produce a second pre-stage product 1B having a reference thickness (d1) (step ST3). Subsequently, the second pre-stage product 1B is compression-molded while being heated at the reference temperature (temp1), the reference compressibility (n1), and the reference time (t1) to generate the container 1 (step ST4).

<Experimental results>
A moisture absorption resistance test was carried out on the container 1. The test results will be described with reference to FIG. Regarding the case where the reference ratio (m1), which is the ratio (w2 / w1) of the weight (w2) of the resin fiber 64 to the weight (w1) of the paper fiber 62, is 6% and 12%, the first pre-stage product 1A is used. The second pre-stage product 1B was produced from the first pre-stage product 1A. Then, the second pre-stage product 1B was compressed while being heated to produce a container 1 to be tested. As the resin fiber, a grade called E400 of SWP (registered trademark) of Mitsui Chemicals, Inc. was used. The melting point of E400 is 135 degrees Celsius (° C.). The reference temperature (temp1) was 150 degrees Celsius, the reference compression rate (n1) was 2.5, and the reference time (t1) was 5 seconds (sec). Then, the container 1 was left in a closed space where the humidity was set to 85% (%) and the temperature was set to 35 degrees Celsius (° C.) for 12 hours (hour), and the increase in weight was measured. When the reference ratio (m1) was 6%, the weight increase rate was 5.5%, and when the reference ratio (m1) was 12%, the weight increase rate was 4.8%. From this, it can be seen that by increasing the reference ratio (m1) to more than 6%, the rate of increase in weight is reduced and the moisture absorption resistance is improved. It can also be seen that the decrease in the weight increase rate is not proportional to the increase in the reference ratio (m1). Furthermore, it can be expected that the decrease in the weight increase rate becomes slower as the reference ratio (m1) increases. From this, if the resin in which the resin fibers 64 are melted and solidified is distributed in an appropriate ratio in the region on the surface side of the container 1, the resin distributed on the center side of the container 1 has hygroscopicity. It can be seen that the contribution is small.

<Surface and internal condition of the second pre-stage product 1B and container 1>
The surface and internal states of the second pre-stage product 1B and the container 1 will be described with reference to FIGS. 19 to 22. The internal state indicates the state of the cross section in the thickness direction of each base material. 19 to 22 are micrographs of the second pre-stage product 1B and the container 1. The magnification of the micrograph was 20 times. In FIGS. 19 to 22, the higher the proportion of the resin, the whiter the appearance, and the higher the proportion of the paper fiber, the blacker the appearance.

As shown in FIG. 19, on the surface of the second pre-stage product 1B, a portion having a large proportion of paper fibers (a portion that looks blackish) is exposed. On the other hand, as shown in FIG. 21, the surface of the container 1 looks whitish as a whole. This means that the portion with a large proportion of paper fibers is not exposed and is substantially covered with the resin.

As shown in FIG. 20, in the central region A1 in the cross section of the second pre-stage product 1B, the thermoplastic resin is uniformly distributed between the paper fibers. The region A2 on the surface side in the cross section of the second pre-stage product 1B is a region in which the ratio of the resin to the paper fiber is smaller than that in the central region A1.

As shown in FIG. 22, when the central region A1 and the surface side region A2 are compared in the cross section of the container 1, the ratio of the resin to the paper fiber is larger in the surface side region A2 than in the central region A1. Understand.

Comparing FIGS. 20 and 22, it can be seen that the resin distributed in the central region A1 in the second pre-stage product 1B moved to the surface side region A2 in the molding process.

Further, before the molding step, the region A2 on the surface side is a region in which the ratio of the resin to the paper fiber is smaller than that of the central region A1 (see FIG. 20). On the other hand, after the molding step, the surface side region A2 is a region in which the ratio of the resin to the paper fiber is large with respect to the central region A1 (see FIG. 22). That is, focusing on the ratio of the resin to the paper fiber, it can be seen that the characteristics of the central region A1 and the surface side region A2 are interchanged before and after the molding process.

<Hygroscopicity of container 1>
As shown in FIG. 23, the water molecules 200 that have reached the surface of the container 1 are formed by the resin obtained by dissolving and solidifying the resin fibers 64 distributed on the surface of the container 1, as shown by arrows C1 and C2. It is repelled to the outside. Therefore, the water molecule 200 cannot easily enter the inside of the container 1.

<Adhesion of container 1 to plastic film>
As shown in FIG. 24, the plastic film 210 is integrated with the resin in which the resin fibers 64 distributed on the surface of the container 1 are dissolved and solidified. Since the plastic film 210 is made of resin, it is firmly adhered to the container 1.

<Adhesion of container 1 to metal foil>
As shown in FIG. 25, the metal foil 220 is welded to the resin in which the resin fibers 64 distributed on the surface of the container 1 are melted and solidified. The metal foil 220 is, for example, an aluminum foil. In particular, when the surface of the metal leaf 220 is not smooth and is a non-smooth surface having a certain degree of unevenness, the resin penetrates between the irregularities and the metal leaf 220 is firmly adhered to the surface of the container 1. Alternatively, the metal leaf is firmly adhered to the surface of the container 1 by forming the surface of the container 1 into a shape having fine irregularities.

The cosmetic container of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

1 Packaging container 2 Base material 6 Mixing liquid manufacturing tank 8 Mixing liquid adjusting device 10 First pre-stage

product generating device

18A, 18B First mold member 22 Second mold member 22A Upper mold member 22B Lower mold member 20 Molding device 20
30 Drying device 60 Mixing solution 62 Paper fiber 64 Resin fiber 100 Manufacturing system

Claims

A mixed liquid generation step of pouring paper and a resin fiber composed of a thermoplastic resin into a predetermined liquid to generate a mixed liquid containing the paper fiber constituting the paper and the resin fiber.
A first-type member in which a reticulated member having a plurality of through holes is arranged is arranged in the mixed liquid, and the mixed liquid is sucked in a direction toward the first-type member to come into contact with the reticulated member. In the state, the first pre-stage product generation step of producing the first pre-stage product and
A drying step of drying the first pre-stage product to produce a second pre-stage product,
A molding step of producing a packaging container having a predetermined shape by compression molding the second pre-stage product while heating it using the second mold member.
Have,
In the molding step, the temperature of the second mold member is set to a reference temperature (temp1) in a predetermined temperature range higher than the melting point of the thermoplastic resin, and the second type member is set with respect to the thickness (d2) of the packaging container. The compression ratio (d1 / d2), which is the ratio of the thickness (d1) of the pre-stage product, is set to a predetermined reference compression ratio (n1), and the execution time of the molding step is set to a predetermined reference time (t1).
The reference compression ratio (n1) and the reference time (t1) are such that the ratio of the thermoplastic resin to the paper fiber in the packaging container is relative to the central portion in the thickness direction of the packaging container. It is specified to be relatively large on the surface side,
Manufacturing method of packaging container.
The reference compression ratio (n1) is higher than the compression ratio under the standard conditions, which are the standard manufacturing conditions for paper molds, in order for the molten thermoplastic resin to effectively move to the surface side of the second pre-stage product. Specified as a large compression ratio,
The method for manufacturing a packaging container according to claim 1.
In the reference time (t1), after the thermoplastic resin in the molten state moves to the surface side of the second front stage product in the thickness direction of the second front stage product, the center side of the second front stage product is set. In order to suppress the behavior of returning to, it is specified as a time shorter than the compression time under the standard conditions, which is the standard manufacturing condition of the paper mold.
The method for manufacturing a packaging container according to claim 1.
The reference compression ratio (n1) is defined as a compression ratio larger than the standard compression ratio in the paper mold, and the reference time (t1) is defined as a time shorter than the standard time in the paper mold. Yes,
The method for manufacturing a packaging container according to claim 1.
In the mixed solution, the ratio (w2 / w1) of the weight (w2) of the resin fiber to the weight (w1) of the paper fiber is a reference ratio (m1) defined in a range smaller than the standard ratio in the paper mold. )
The method for manufacturing a packaging container according to claim 1.
A packaging container made of a base material in which a thermoplastic resin is distributed in paper fibers.
A packaging container in which the thermoplastic resin is distributed in a relatively large amount in a portion on the surface side of the substrate with respect to a portion on the center side of the substrate in the thickness direction of the substrate.