Bottle container and method of manufacturing the bottle container

Abstract

This bottle container manufacturing method comprises: a first step of introducing a cylindrical translucent resin material into a cavity of a blow molding mold including a pair of mold bodies and a transfer part provided on a cavity surface of at least one of the pair of mold bodies and having a minute irregularity pattern formed thereon; a second step of molding a bottle body by inflating the translucent resin material introduced into the cavity by blow molding and directly transferring the minute irregularity pattern of the transfer part onto an outer surface of the bottle body; and a third step of extracting the bottle body including a decorative part that includes a minute irregularity shape corresponding to the minute irregularity pattern and partially decorates the outer surface by showing a structural color.

Description

[Technical Field]

[0001] The present disclosure relates to a bottle container and a method for manufacturing the bottle container. [Background technology]

[0002] Patent Document 1 discloses a composite container comprising a container body, a plastic member attached in close contact with the outside of the container body, and a structural color display portion on the outer surface of the plastic member that includes a fine uneven shape and exhibits a structural color. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-26299 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the composite container of Patent Document 1, the plastic member provided with the structural color display portion is made of a resin different from the resin that constitutes the container body. Therefore, if one wants to recycle only the container body, the plastic member must be separated from the container body, which is time-consuming. Furthermore, in the case of discarded containers, it is unhygienic for someone who picks up the container to peel off the plastic member from the container.

[0005] Furthermore, Patent Document 1 requires that the structural color display portion be formed on the outer surface of the plastic member. Therefore, regardless of the position, size, or extent of the structural color display portion on the container body, the tubular plastic member is wrapped around the container body so as to cover the formation position of the structural color display portion. Therefore, the area surrounding the structural color display portion is dominated by the texture and feel of the surface of the plastic member, and the structural color display portion may not stand out. Furthermore, there is also the problem that the structural color display portion can only be formed on a portion of the plastic member where it can be attached.

[0006] In addition, in Patent Document 1, the structural color display part is formed on a film-like plastic member formed on the outside of the container body. Therefore, the design of the structural color display part is restricted to designs that can be formed on the film, which presents a problem of limited freedom of design.

[0007] In addition, in Patent Document 1, a surface texture is provided on the inner surface of a blow molding die, and this surface texture is transferred to the outer surface of the blow-molded plastic part during molding. As a result, a structural color display part including a fine uneven texture is formed on the container body. With this method, heat from the resin is transferred from the surface texture to the molding die and lost, which reduces the fluidity of the resin and may prevent the fine uneven texture from being transferred accurately.

[0008] Therefore, one embodiment of the present disclosure provides a bottle container that can reduce the effort required for recycling.

[0009] Furthermore, one embodiment of the present disclosure provides a bottle container that can make the decorative portion stand out from other portions of the bottle and that allows for greater freedom in determining the position where the decorative portion is formed.

[0010] Furthermore, one embodiment of the present disclosure provides a method for manufacturing a bottle container that can transfer a fine concave-convex shape with high precision by blow molding. [Means for solving the problem]

[0011] A bottle container according to one embodiment of the present disclosure includes a bottle body having at least a mouth portion and a body portion provided below the mouth portion, the bottle body being formed from a translucent resin, with the translucent resin material being exposed on the entire outer surface so that the presence or absence of contents can be visually confirmed, and a decorative portion including a finely uneven shape formed directly on the outer surface of the bottle body, which partially decorates the outer surface of the bottle body by exhibiting a structural color.

[0012] According to this configuration, the decorative portion exhibiting the structural color is formed on the bottle body, thereby improving the design of the bottle container's appearance. Furthermore, the decorative portion includes a fine uneven shape formed directly on the outer surface of the bottle body, and is integrally formed with the bottle body using the translucent resin that constitutes the bottle body. Therefore, after use, there is no need to separate the bottle body and the decorative portion, and the bottle container can be disposed of or recycled depending on the type of resin used in the bottle body. Furthermore, if the decorative portion is an identification portion for identifying the type of resin used in the bottle body, the bottle can be disposed of hygienically without directly touching the bottle body by using a tool such as tongs.

[0013] In addition, since the decorative portion is formed directly on the outer surface of the bottle body, the color of the decorative portion can be made to stand out against the outer surface of the bottle container.Furthermore, since the decorative portion can be provided by forming a fine uneven shape in any position or area on the outer surface of the bottle body, there is increased freedom in terms of the position and design of the decorative portion.

[0014] In the bottle container according to one embodiment of the present disclosure, the translucent resin may include a colorless and transparent polyethylene terephthalate resin.

[0015] With this configuration, the decorative portion is surrounded by a colorless and transparent polyethylene terephthalate resin, which allows the color of the decorative portion to stand out against the surrounding transparent parts, making it easy to distinguish the position, size, and extent of the decorative portion on the container body.

[0016] In a bottle container according to one embodiment of the present disclosure, the body portion does not have to be formed with a functional film made of a resin having a function different from that of the translucent resin forming the bottle body, so as to cover the entire periphery of the body portion.

[0017] In the bottle container according to one embodiment of the present disclosure, the decorative portion may include at least one of letters, illustrations, and marks.

[0018] In a bottle container according to one embodiment of the present disclosure, the decorative portion may include a decorative area including at least one of letters, illustrations, and marks displayed inside by a surface structure of the translucent resin that is different from the fine uneven shape.

[0019] A method for manufacturing a bottle container according to one embodiment of the present disclosure includes a first step of introducing a tubular translucent resin material into a cavity of a blow molding mold including a pair of mold bodies and a transfer portion having a fine uneven pattern formed thereon, the transfer portion being provided on the cavity surface of at least one of the pair of mold bodies; a second step of molding a bottle body by expanding the translucent resin material introduced into the cavity by blow molding, and directly transferring the fine uneven pattern of the transfer portion onto the outer surface of the bottle body; and a third step of removing the bottle body, which includes a decorative portion having a fine uneven shape corresponding to the fine uneven pattern and exhibiting a structural color to partially decorate the outer surface.

[0020] This method makes it possible to manufacture a bottle container according to one embodiment of the present disclosure.

[0021] In the method for manufacturing a bottle container according to one embodiment of the present disclosure, the blow molding die may include a heat insulating section provided on the opposite side of the cavity with respect to the transfer section.

[0022] According to this method, a pair of mold bodies has a heat insulating section on the opposite side of the cavity from the transfer section. This reduces the rate at which heat from the resin material is transferred from the transfer section to the mold body when transferring a fine concave-convex pattern to the resin material. This prevents a decrease in the fluidity of the resin material, allowing the fine concave-convex pattern to be transferred to the resin material with high accuracy.

[0023] In one embodiment of the method for manufacturing a bottle container according to the present disclosure, the second step may include a step of transferring the fine uneven pattern to the bottle body while applying a force to the transfer section that resists the pressure of air introduced into the bottle body during the blow molding.

[0024] According to this method, a force acting in the opposite direction to the air pressure is generated from the outside of the mold body, so that the bottle container is sandwiched from both the inside and outside, and a fine concave-convex pattern can be transferred, thereby improving the transfer rate.

[0025] In one embodiment of the method for manufacturing a bottle container according to the present disclosure, the second step may include a step of transferring the fine uneven pattern to the bottle body while expelling any remaining air in the cavity to the outside of the mold body during the blow molding.

[0026] This method allows the removal of residual air from the cavity, which creates resistance during blow molding. This reduces the amount of residual air, lowering air resistance and the internal pressure of the cavity, thereby improving the transfer rate.

[0027] In the method for manufacturing a bottle container according to one embodiment of the present disclosure, the translucent resin material may include a colorless and transparent polyethylene terephthalate resin material.

[0028] Compared to polyolefin resins such as polyethylene resin and polypropylene resin, polyethylene terephthalate resin has a higher melting point and a higher viscosity when molten. Therefore, unless the resin temperature is maintained relatively high and a decrease in fluidity is suppressed, it is difficult to accurately transfer a fine concave-convex pattern. Therefore, the effect of the aforementioned heat insulating portion, which can reduce the rate of heat transfer from the transfer portion to the mold body, is very suitable when the translucent resin material is polyethylene terephthalate resin.

[0029] In the method for manufacturing a bottle container according to an embodiment of the present disclosure, the first step may include a step of setting a preform having a bottom in the blow molding die.

[0030] A method for manufacturing a bottle container according to another embodiment of the present disclosure includes a step of molding a bottle body using a translucent resin material, and a step of pressing a plate having a transfer portion on which a fine uneven pattern is formed against the outer surface of the bottle body, thereby directly transferring the fine uneven pattern of the transfer portion onto the outer surface of the bottle body.

[0031] This method can also be used to manufacture a bottle container according to one embodiment of the present disclosure. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic perspective view of a bottle container according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4A] FIG. 4A is an enlarged view showing a part of the decorative portion (first pattern) of FIG. [Figure 4B] FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG. 4A. [Figure 4C] FIG. 4C is an enlarged view showing a main part of the uneven shape of FIGS. 4A and 4B. [Figure 5A] FIG. 5A is an enlarged view showing a part of the decorative portion (second pattern) of FIG. [Figure 5B] FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A. [Figure 5C] FIG. 5C is an enlarged view showing a main part of the uneven shape of FIGS. 5A and 5B. [Figure 6] FIG. 6 is a schematic perspective view of a bottle container according to one embodiment of the present disclosure. [Figure 7]FIG. 7 is a schematic perspective view of a bottle container according to one embodiment of the present disclosure. [Figure 8A] FIG. 8A is a diagram showing a part of the manufacturing process of the bottle container. [Figure 8B] FIG. 8B is a diagram showing the next step of FIG. 8A. [Figure 8C] FIG. 8C is a diagram showing the next step of FIG. 8B. [Figure 8D] FIG. 8D shows the next step of FIG. 8C. [Figure 8E] FIG. 8E shows the next step of FIG. 8D. [Figure 8F] FIG. 8F shows the next step of FIG. 8E. [Figure 9A] FIG. 9A is a diagram illustrating a process related to the transfer of a fine concave-convex pattern. [Figure 9B] FIG. 9B is a diagram showing the next step of FIG. 9A. [Figure 10] FIG. 10 is a diagram illustrating the steps involved in transferring the fine concave-convex pattern. [Figure 11A] FIG. 11A is a diagram illustrating a process related to the transfer of a fine concave-convex pattern. [Figure 11B] FIG. 11B shows the next step in FIG. 10A. [Figure 12] FIG. 12 is a diagram showing the shape of the transfer pattern used in the experimental example. [Figure 13] FIG. 13 is a schematic perspective view of a bottle container according to another embodiment of the present disclosure. [Figure 14] FIG. 14 is a schematic diagram showing a first modified example of the decorative portion. [Figure 15] FIG. 15 is a schematic diagram showing a second modified example of the decorative portion. DETAILED DESCRIPTION OF THE INVENTION

[0033] Next, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. <Overall configuration of bottle container 1> Fig. 1 is a schematic perspective view of a bottle container 1 according to one embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. It is a diagram showing the structure of the decorative part 21 shown in Fig. 1. In the following, "upper" and "lower" are used to explain the positional relationship of parts of the bottle container 1, and "upper" and "lower" mean the "upper side" and "lower side" when the bottle container 1 is upright.

[0034] The bottle container 1 is a plastic bottle, and has a capacity of, for example, about 150 mL to 2 L. The bottle container 1 is filled with a liquid. The liquid is not particularly limited, but examples thereof include beverages such as drinking water, soft drinks, tea, coffee, black tea, cocoa, and alcoholic drinks, as well as liquid seasonings such as cooking oil, soy sauce, cooking sake, mirin, sauce, and cooking sauce.

[0035] The bottle container 1 includes a bottle body 2 and a cap 3. The bottle body 2 integrally includes a mouth 4, a shoulder 5 formed below the mouth 4, a body 6 formed below the shoulder 5, and a bottom 7 formed below the body 6.

[0036] The mouth 4 is a spout for pouring liquid into the bottle container 1. The mouth 4 is formed in a cylindrical shape, and a threaded portion 8 is formed on the circumferential surface of the mouth 4. The cap 3 is screwed onto the threaded portion 8 of the mouth 4 to seal the bottle body 2.

[0037] The shoulder portion 5 is continuous with the mouth portion 4 and is formed in a shape that gradually increases in width from the mouth portion 4 downward. In this embodiment, the shoulder portion 5 has an apex at the connection point with the mouth portion 4 and is formed in a generally quadrangular pyramid shape with four flat surfaces 10 (outer surfaces 9) that extend downward in all directions from the apex. The shoulder portion 5 is formed by combining multiple flat plastic panels 11 (approximately triangular flat plastic panels 11 in FIG. 1 ) that are arranged continuously along the circumferential direction of the bottle body 2. However, the shape of the shoulder portion 5 is not particularly limited, and it may be formed in a dome shape whose diameter gradually increases downward from the apex. In this case, the shoulder portion 5 is formed by a curved surface that bulges outward from the bottle body 2 and continues along the circumferential direction of the bottle body 2.

[0038] The body 6 is continuous with the shoulder 5 and has a cylindrical shape with a substantially constant width extending downward from the shoulder 5. In this embodiment, the body 6 is formed in a substantially rectangular cylindrical shape, but it may be formed in another polygonal cylindrical shape, such as a substantially hexagonal cylindrical shape, or may be formed in a cylindrical shape. A separating rib 12 is formed in the middle of the body 6 in the vertical direction. The separating rib 12 is a ring-shaped groove extending along the circumferential direction of the body 6 and formed on the outer surface 9 of the bottle body 2, and separates the body 6 into multiple sections in the vertical direction. In this embodiment, only one separating rib 12 is formed. As a result, the body 6 is separated into an upper section 13 above the separating rib 12 and a lower section 14 below the separating rib 12. The upper section 13 and lower section 14 of the body 6 may be referred to as the first section and the second section of the body 6, respectively. A plurality of separating ribs 12 may also be formed. For example, if two separating ribs 12 are formed, the body 6 may be separated into three parts: an upper part, a lower part, and an intermediate part between the upper and lower parts.

[0039] The upper portion 13 of the body 6 is formed in a generally rectangular tubular shape, with four flat surfaces 15 (outer surface 9) continuing from the four flat surfaces 10 of the shoulder portion 5. The upper portion 13 of the body 6 is formed by combining a plurality of flat plastic panels 16 (flat plastic panels 16 having a generally rectangular shape in FIG. 1 ) arranged continuously along the circumferential direction of the bottle body 2. The lower portion 14 of the body 6 is also formed in a generally rectangular tubular shape, like the upper portion 13 of the body 6, but the panels constituting the tube may be curved plastic panels 18. Therefore, the lower portion 14 of the body 6 may have a curved surface 17 (outer surface 9) that bulges slightly outward from the bottle body 2.

[0040] The bottom 7 is made of a plastic panel 19 that closes the lower part of the body 6. Although not shown, the bottom 7 may have a known shape that has a recess in the center and an installation portion on the periphery.

[0041] The shape of the bottle body 2 is not limited to the shape shown in Fig. 1. For example, in addition to the separating rib 12 shown in Fig. 1, the body 6 may be formed with ribs or recesses to improve the strength of the bottle body 2, or ribs with special shapes to make the bottle body 2 easier to crush.

[0042] The bottle body 2 is made of a thermoplastic translucent resin. The translucent resin is translucent to visible light and may include resins with a milky white or other opaque color, or transparent resins such as colored and colorless. More specifically, examples of the translucent resin include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethylpentene (PMP), ethylene tetracyclododecene (E / TD), and polyacrylonitrile (PAN). Among these, polyethylene terephthalate resin is preferred in view of transparency, rigidity, light weight, and the like, and colorless and transparent polyethylene terephthalate resin is even more preferred. The above resins can be used alone or in combination. The bottle body 2 may be formed into a single-layer structure or a multilayer structure in which multiple resins are laminated.

[0043] Furthermore, with reference to FIGS. 2 and 3, the thickness T1 of the container body (for example, the thickness of each of the plastic panels 11, 16, 18, and 19) may be, for example, 100 μm to 500 μm.

[0044] The bottle body 2 is made of a single layer of the resin described above, and this single layer defines the bottle storage chamber 20 in which the contents are stored. The translucent resin material constituting the bottle body 2 is entirely exposed as the outer surface 9 of the bottle body 2 so that the presence or absence of the contents can be visually confirmed. "The translucent resin material is entirely exposed as the outer surface 9" may mean, for example, that the body 6 of the bottle body 2 is not entirely covered with a film. Examples of such a covering film include functional films and packaging films. The functional film may be made of a resin different from the resin of the bottle body 2 and have a different function (e.g., light blocking, gas / water vapor barrier properties, etc.) from the resin of the bottle body 2. The packaging film may be a film bearing, for example, the product name of the contents, nutritional information, or an identification mark for the material for separate collection. Furthermore, "The translucent resin material is entirely exposed as the outer surface 9" may mean that the bottle container 1 is a so-called label-less bottle. Therefore, a sticker bearing the information necessary for selling the beverage or the like contained in the bottle container 1 as a product may be affixed to the outer surface 9 of the bottle body 2 in a pinpoint manner. Examples of such a sticker include a sticker bearing an identification mark for the material to be sorted and collected, a product name, etc. <Detailed explanation of decorative part 21> As described above, in the bottle container 1, the resin material of the bottle body 2 is entirely exposed as the outer surface 9. Therefore, the texture of the outer surface 9 of the bottle body 2 is governed by the texture of the resin of the bottle body 2. For example, if the bottle body 2 is made of transparent polyethylene terephthalate resin, the bottle body 2 has a transparent, smooth texture, and the amount and color of the contents can be clearly seen from the outer surface 9.

[0045] If the outer surface 9 of the bottle body 2 is transparent and smooth, a decorative portion 21 exhibiting a structural color can be formed directly on the outer surface 9 of the transparent resin, thereby partially decorating the bottle body 2 with the decorative portion 21. A design based on a structural color is also imparted in the invention described in Patent Document 1, but by forming the decorative portion 21 directly on the transparent polyethylene terephthalate resin, the effect of improving the design provided by the decorative portion 21 can be further enhanced.

[0046] Therefore, in this embodiment, the decorative portion 21 is formed directly on the outer surface 9 of the bottle body 2. There are no particular limitations on the location of the decorative portion 21, as long as it is on the outer surface 9 of the bottle body 2. For example, from top to bottom in Fig. 1, it may be formed on the shoulder portion 5 of the bottle body 2, on the upper portion 13 of the body 6 of the bottle body 2, or on the lower portion 14 of the body 6 of the bottle body 2. In this embodiment, for convenience, the three decorative portions 21 are shown as, from top to bottom, a first decorative portion 21A, a second decorative portion 21B, and a third decorative portion 21C.

[0047] The first decorative portion 21A is formed on the shoulder portion 5 made of a flat plastic panel 11. Therefore, the first decorative portion 21A is formed on the flat surface 10 on the outer surface 9 of the bottle body 2. The second decorative portion 21B is formed on the upper portion 13 of the body 6 made of a flat plastic panel 16. Therefore, the second decorative portion 21B is formed on the flat surface 15 on the outer surface 9 of the bottle body 2. The third decorative portion 21C is formed on the lower portion 14 of the body 6 made of a curved plastic panel 18. Therefore, the third decorative portion 21C is formed on the curved surface 17 on the outer surface 9 of the bottle body 2.

[0048] Next, the three-dimensional structure of the decorative part 21 will be described with reference to Figures 4A to 4C and 5A to 5C. Two examples of the three-dimensional structure of the decorative part 21 are shown below, but the three-dimensional structures of the decorative part 21 in Figures 4A to 4C and 5A to 5C may be used for any of the first decorative part 21A, the second decorative part 21B, and the third decorative part 21C. For example, the three-dimensional structure of the decorative part 21 in Figures 4A to 4C may be used for the first decorative part 21A and the second decorative part 21B, and the three-dimensional structure of the decorative part 21 in Figures 5A to 5C may be used for the third decorative part 21C. The plastic panels 11, 16, 18, and 19 described above are collectively referred to as plastic panel 54.

[0049] First, the decorative portion 21 includes fine uneven shapes 22, 23 formed directly on the plastic panel that constitutes the bottle body 2. Here, the "fine uneven shapes 22, 23 formed directly on the plastic panel 54" may refer to a fine uneven pattern formed by directly transferring a transfer pattern 46 onto the plastic panel 54, as will be described later. The fine uneven shapes 22, 23 may be formed integrally and inseparably with the plastic panel 54 on the outer surface 9 of the plastic panel 54 that defines the bottle storage chamber 20, as shown in Figures 4B and 5B, for example.

[0050] The minute concave and convex shapes 22 and 23 are formed by a combination of concave portions 25 and 27 and convex portions 24 and 26.

[0051] 4A to 4C, a fine uneven shape 22 is formed, including a large number of convex portions 24, each formed in a pyramidal shape and arranged in a matrix, and concave portions 25 between adjacent convex portions 24. The convex portions 24 may be in the shape of a quadrangular pyramid as shown in FIG. 4C, or may be in the shape of another polygonal pyramid such as a triangular pyramid, or may be in the shape of a cone.

[0052] The pitch P1 of the fine uneven shape 22 (for example, the distance between the tops of adjacent convex portions 24) may be, for example, 0.1 μm to 300 μm. The height H1 of the fine uneven shape 22 (for example, the distance from the bottom surface of the concave portion 25 to the top of the convex portion 24) may be, for example, 0.1 μm to 300 μm. Here, in order to define the fine uneven shape 22 as "fine," it is preferable that both the pitch P1 and the height H1 are on the order of microns (for example, about 0.1 μm to 100 μm).

[0053] 5A to 5C, a fine uneven shape 23 is formed, including a large number of protrusions 26 each formed in a line and arranged in a stripe pattern, and linear recesses 27 between adjacent protrusions 26. The cross-sectional shape of the fine uneven shape 23 may be a wave shape as shown in Fig. 5B, or may be a sawtooth shape, a rectangular shape, or the like.

[0054] The pitch P2 of the fine unevenness 23 (for example, the distance between the tops of adjacent convex portions 26) may be, for example, 0.1 μm to 300 μm. The height H2 of the fine unevenness 23 (for example, the distance from the bottom surface of the concave portion 27 to the top of the convex portion 26) may be, for example, 0.1 μm to 300 μm. Here, in order to define the fine unevenness 23 as "fine," it is preferable that both the pitch P2 and the height H2 are on the order of microns (for example, about 0.1 μm to 100 μm).

[0055] In this way, by forming the decorative portion 21 including the fine uneven shapes 22, 23 on the outer surface 9 of the bottle body 2, the outer surface 9 of the bottle body 2 exhibits a structural color. As a result, the bottle body 2, which is formed entirely transparently from polyethylene terephthalate resin, is partially decorated. The decorative pattern is not particularly limited, and may be, for example, a pattern with a design such as a geometric pattern, three-dimensional letters, or a combination thereof, or a pattern that conveys information such as a product name or an identification of the material of the bottle body 2. Note that "structural color" refers to a color that is produced by an optical phenomenon based on a physical structure, such as diffraction, refraction, interference, or scattering of light caused by the fine uneven shapes 22, 23.

[0056] For example, the decorative portion 21 may include at least one of letters, illustrations, and marks, as shown in Fig. 6. In Fig. 6, as an example of a case where the decorative portion 21 (second decorative portion 21B) is a letter, the decorative portion 21 (letter "A") formed by the fine uneven shapes 22, 23 is shown hatched. The pattern shown hatched in this manner may also be other letters (such as a product symbol logo), illustrations, and marks (for example, a product symbol illustration, a product symbol mark, a company house mark, etc.), or a combination thereof.

[0057] Furthermore, as shown in FIG. 7, the decorative portion 21 may include a decorative region 55 including a design pattern 56 displayed therein. In FIG. 7, the rectangular decorative region 55 is indicated by hatching. The design pattern 56 within the decorative region 55 includes at least one of letters, illustrations, and marks. The design pattern 56 is displayed within the decorative region 55 by being surrounded by the minute uneven shapes 22, 23, forming an outline. The design pattern 56 is formed by a surface structure of the bottle body 2 (translucent resin) that is different from the minute uneven shapes 22, 23. The surface structure forming the design pattern 56 may be, for example, a surface structure consisting of a smooth surface without the minute uneven shapes 22, 23. Alternatively, it may be a surface structure consisting of uneven shapes larger than the minute uneven shapes 22, 23 (for example, an uneven surface structure roughened by blasting or the like).

[0058] In addition, which of the above-mentioned fine uneven shapes 22, 23 that make up the decorative portion 21 to adopt may be determined, for example, based on the shape of the outer surface 9 of the bottle body 2 on which the decorative portion 21 is formed.

[0059] For example, a decorative portion 21 based on a fine unevenness 22 shown in FIGS. 4A to 4C is preferably formed on the curved surface 17 of the outer surface 9 of the bottle body 2. During blow molding of the bottle body 2, the curved surface 17 contacts the transfer pattern 46 of the mold 39 from its top, and the further away from the top, the more delayed the pattern transfer to that portion. In other words, a time lag occurs in the transfer of the fine unevenness pattern on the same curved surface 17. Therefore, unevenness in the fine unevenness is more likely to occur than when formed on flat surfaces 10 and 15. Therefore, it may be preferable to form a fine unevenness 22 (see FIGS. 4A to 4C) in a matrix pattern on the curved surface 17, in which each uneven unit is more finely divided than the fine unevenness 23 (see FIGS. 5A to 5C) in a stripe pattern. However, unevenness in the fine unevenness is thought to result in complex reflection patterns due to light interference. Therefore, when a design that allows for strong lighting is required, the fine uneven shape 23 of the stripe pattern may be formed on the curved surface 17 portion.

[0060] On the other hand, the flat surfaces 10 and 15 of the outer surface 9 of the bottle body 2 may be formed with either a decorative portion 21 based on a fine uneven shape 22 as shown in FIGS. 4A to 4C or a decorative portion 21 based on a fine uneven shape 23 as shown in FIGS. 5A to 5C. In the flat surfaces 10 and 15, the resin constituting the flat surfaces 10 and 15 uniformly contacts the transfer pattern 46 of the mold 39 during blow molding of the bottle body 2, allowing for more uniform transfer than the curved surface 17. Therefore, the pattern of the fine uneven shape constituting the decorative portion 21 is less restricted than that of the curved surface 17. When forming the fine uneven shape 23 in a striped pattern, the stripe direction is preferably vertical to the bottle body 2. Typically, people view the decorative portion 21 while holding or standing the bottle body 2 upright. This is because people can more easily perceive natural light if the direction of their line of sight when viewing the decorative portion 21 is aligned (parallel) with the stripe direction.

[0061] As described above, according to the bottle container 1, the decorative portion 21 exhibiting a structural color is formed on the bottle body 2, thereby improving the aesthetic design of the bottle container 1. Furthermore, the decorative portion 21 includes fine irregularities 22, 23 formed directly on the outer surface 9 of the bottle body 2, and is formed integrally with the bottle body 2 using the translucent resin that constitutes the bottle body 2. Therefore, after using the bottle container 1, there is no need to separate the bottle body 2 and the decorative portion 21, and the bottle can be disposed of or recycled depending on the type of resin used in the bottle body 2. Furthermore, if the decorative portion 21 is an identification portion formed of a pattern that conveys information such as an identification mark for the material of the bottle body 2, the bottle can be disposed of hygienically without directly touching the bottle body 2, for example, by using a tool such as tongs.

[0062] Furthermore, because the decorative portion 21 is formed directly on the outer surface 9 of the bottle body 2, the color of the decorative portion 21 can stand out against the outer surface 9 of the bottle container 1. Therefore, by providing information such as the product name or an identification marking of the material of the bottle body 2 to the decorative portion 21, it becomes unnecessary to print the information, and an environmentally friendly bottle container 1 can be provided.

[0063] Furthermore, the decorative portion 21 can be provided by forming minute uneven shapes 22, 23 at any position or area on the outer surface 9 of the bottle body 2, which increases the degree of freedom in determining the position where the decorative portion 21 is formed.

[0064] Furthermore, in this embodiment, the decorative portion 21 is surrounded by a colorless and transparent polyethylene terephthalate resin, which allows the color of the decorative portion 21 to stand out against the surrounding transparent parts. This makes it easy to distinguish the position, size, and extent of the decorative portion 21 on the container body. <Method of manufacturing bottle container 1> 8A to 8F are diagrams showing, in order of steps, some of the manufacturing steps for the bottle container 1. Fig. 9A and Fig. 9B are diagrams for explaining steps related to the transfer of the transfer pattern 46.

[0065] To manufacture the bottle container 1, for example, a preform 28 for the bottle body 2 is prepared. The preform 28 may be one that has been prepared in advance, or may be molded using a light-transmitting resin as shown in FIG. 8A. When molding the preform 28, a preform molding machine 29 is used. The preform molding machine 29 may perform batch injection molding while continuously melting the light-transmitting resin.

[0066] The preform molding machine 29 may include a cylinder 30, an extruder 31 (screw) disposed in the internal space of the cylinder 30, a hopper 33 that supplies resin pellets 32 to the internal space of the cylinder 30, and a mold 34 attached to the tip of the cylinder 30. The mold 34 may include a fixed mold 35 fixed to the cylinder 30, and a movable mold 36 that is provided so that the fixed mold 35 can be opened and closed.

[0067] First, with the movable mold 36 closed relative to the fixed mold 35 (the state shown in FIG. 8A ), a melt of resin pellets 32 (molten resin 37) supplied from a hopper 33 is injected into the mold 34. After the injection, the injection force of the preform molding machine 29 is maintained for a certain period of time. Thereafter, the movable mold 36 is opened, and the preform 28 is removed. This forms a bottomed, cylindrical preform 28.

[0068] 8B, the preform 28 is transported to the heater 38. The preform 28 is heated and softened as it passes through the heater 38. The set temperature of the heater 38 varies depending on the raw material resin of the preform 28, but may be set to 80°C to 120°C, for example, when polyethylene terephthalate resin is used.

[0069] 8C and 8D, the softened preform 28 is inserted into a pair of molds 39 of a blow molding machine (not shown). The preform 28 is set in the blow molding machine by being sandwiched between the pair of molds 39. The blow molding may be performed by biaxial stretch blow molding, which stretches the preform 28 in the axial and radial directions.

[0070] For example, referring to FIG. 8E, the preform 28 set in a pair of molds 39 is stretched in the axial direction by a stretch rod or the like. Next, air is blown into the preform 28 via the stretch rod to apply pressure and expand the preform 28 in the axial and radial directions. This forces the resin against the cavity surfaces 40 (inner surfaces) of the pair of molds 39, forming the shape of the bottle body 2. The surfaces pressed against the cavity surfaces 40 of the molds 39 become the outer surfaces 9 of the bottle body 2. Then, after cooling, the pair of molds 39 are opened as shown in FIG. 8F, and the bottle body 2 is removed.

[0071] Here, the decorative portion 21 is formed during the blow molding process shown in Fig. 8E. More specifically, as shown in Fig. 9A, a mold 39 of the blow molding machine includes a mold body 41, an inner metal layer 42, and a heat insulating portion 43.

[0072] The mold body 41 forms the outer shape of the mold 39 of the blow molding machine, and has a cavity 44 formed therein that corresponds to the shape of the bottle container 1.

[0073] The internal metal layer 42 is a metal layer formed on the cavity surface 45 (inner surface) of the mold body 41, and during blow molding, it comes into direct contact with the expanded resin to mold the resin. The internal metal layer 42 is provided with a transfer portion 47 including a transfer pattern 46 for forming the fine uneven shapes 22, 23 of the decorative portion 21. The pattern surface of the internal metal layer 42 on which the transfer pattern 46 is formed forms the cavity surface 40 of the mold 39. The transfer pattern 46 has a fine uneven shape 48 formed therein that is opposite to the fine uneven shapes 22, 23 of the decorative portion 21. The transfer portion 47 is selectively formed at the position on the bottle body 2 where the decorative portion 21 is to be formed. The transfer portion 47 may be formed by directly processing the inner surface (the surface that comes into contact with the resin) of the internal metal layer 42, or may be embedded in the internal metal layer 42 as a nested mold.

[0074] The heat insulating portion 43 is formed between the mold body 41 and the internal metal layer 42. The heat insulating portion 43 may be an insulating plate sandwiched between the mold body 41 and the internal metal layer 42, or may be an insulating layer formed on the cavity surface 45 of the mold body 41. The heat insulating plate may be a resin plate made of a thermosetting resin having relatively high heat resistance, such as a phenolic resin, an epoxy resin, a melamine resin, or a urea resin. The heat insulating layer may be a ceramic film made of an oxide ceramic such as silica, alumina, or zirconia, or a non-oxide ceramic such as mullite, silicon nitride, or silicon carbide.

[0075] 8E, when the resin expands due to air pressure, the resin is pressed against the transfer pattern 46 of the internal metal layer 42, as shown in FIG. 9B. This transfers the fine uneven shape 48 of the transfer pattern 46 to the outer surface 9 of the bottle body 2 as uneven shapes 22, 23. The mold temperature during blow molding varies depending on the raw material resin of the bottle body 2, but may be set to 80°C to 120°C, for example, when polyethylene terephthalate resin is used.

[0076] The air pressure (pressure of compressed air) may be, for example, 1 MPa to 5 MPa.

[0077] As a blow molding method, the method shown in FIG. 10 and FIGS. 11A to 11B may be applied.

[0078] In the method of FIG. 10, a resistance force 58 against the air pressure 57 is applied from outside the mold 39 during the air pressurization shown in FIG. 8E. By generating the resistance force 58 against the air pressure 57 from outside the mold 39, the fine concave-convex shapes 22, 23 can be transferred by sandwiching the bottle body 2 from the inside and outside. This improves the transfer rate. The resistance force 58 may be, for example, a reaction force against the air pressure 57 or an external force acting against the air pressure 57. The reaction force may be generated, for example, by interposing a spring 59 between the mold body 41 and the heat insulating portion 43 and utilizing the elastic force of the spring 59. The external force may be generated, for example, by placing an air cylinder 60 against the mold body 41 and operating the air cylinder 60 to push the mold body 41 inward during air pressurization.

[0079] 11A and 11B, a through-hole 61 that connects the inside and outside of the cavity 44 is formed in the mold 39. This allows the remaining air in the cavity 44, which creates resistance when the bottle body 2 expands due to air pressure, to be discharged in the direction of arrow 62. This reduces the remaining air, lowering air resistance and the internal pressure of the cavity, thereby improving the transfer rate.

[0080] According to the above method, in the pair of molds 39, the heat insulating portion 43 is provided on the side opposite the cavity 44 from the transfer portion 47. This makes it possible to reduce the speed at which heat from the resin material is transferred from the transfer portion 47 to the mold body 41, as shown by arrow 49 in Fig. 9B, when transferring a transfer pattern 46 including a fine concave-convex shape 48 to the resin material. This makes it possible to suppress a decrease in the fluidity of the resin material, and therefore makes it possible to transfer the transfer pattern 46 to the resin material with high accuracy.

[0081] In particular, polyethylene terephthalate resin has a higher melting point and a higher viscosity when molten than polyolefin resins such as polyethylene resin and polypropylene resin. Therefore, it is difficult to accurately transfer the transfer pattern 46 unless the resin temperature is maintained relatively high and a decrease in fluidity is suppressed. In other words, polyethylene terephthalate resin does not have high formability compared to polyethylene resin and polypropylene resin. Therefore, the effect of the heat insulating portion 43, which can reduce the rate of heat transfer from the transfer portion 47 to the mold body 41, is very suitable when the translucent resin material is polyethylene terephthalate resin.

[0082] Furthermore, because the barrel 6 of the bottle body 2 is not covered with a film such as a functional film, the mold temperature during blow molding can be set according to the raw resin of the bottle body 2. By comparison, in the invention described in Patent Document 1, the preform is covered with a plastic member, and the raw resin of the preform (container body) is different from the raw resin of the plastic member. Therefore, during blow molding, the mold temperature must be set by prioritizing either the molding accuracy of the container body or the transfer accuracy of the structural color display portion (fine uneven shape) formed on the plastic member, making temperature control difficult. In this regard, if the bottle body 2 is formed from a single layer of translucent resin and is not covered with a film such as a functional film, as in this embodiment, only one resin needs to be temperature-controlled, simplifying temperature control.

[0083] Below, an experimental example will be shown to prove how much the transfer rate changes depending on whether or not the heat insulating portion 43 is present in the pair of molds 39.

[0084] In this experimental example, a mold 39 having a transfer pattern 46 shown in FIG. 12 was used. The transfer pattern 46 had a fine uneven shape 48 formed thereon, which had a V-shape (wave shape). The angle θ between the top and bottom (groove bottom) of the V-shaped structure that constitutes the fine uneven shape 48 was 42°. The pitch P3 of the fine uneven shape 48 was 2 μm. The depth (mold depth) D1 of the fine uneven shape 48 was 2.605 μm.

[0085] The cavity surface 45 of the mold 39 (see Figures 9A and 9B) includes a non-insulated surface formed of a nickel-plated layer and an insulated surface formed of a zirconia layer corresponding to the insulating portion 43. The evaluation was performed by comparing the transfer depth of the transfer patterns (fine uneven shapes 22, 23) transferred by the non-insulated surface and the insulated surface. The results are shown in Table 1 below. In Table 1, the transfer depth refers to the depth at the deepest position among the unevenness of each transfer pattern.

[0086] [Table 1]

[0087] The results in Table 1 show that for all preforms used, the transfer depth of the heat-insulating surface (with heat-insulating portion 43) was greater than the transfer depth of the non-heat-insulating surface (without heat-insulating portion 43), and the transfer rate was improved. As a result, by providing heat-insulating portion 43 in mold 39, the dependency on the angle of incidence of light can be improved and the reflected light can be strengthened. As a result, the degree of color development in decorative portion 21 can be improved, and the visual recognition ability can be improved.

[0088] Although embodiments of the present disclosure have been described, the present disclosure may be embodied in other forms.

[0089] For example, in the above-described embodiment, the fine uneven shapes 22, 23 of the decorative portion 21 were exposed without being covered. However, as shown in FIGS. 13 to 15 , they may be covered with covering sheets 50, 51. More specifically, this is the case when a recess 52 (which may be a rib) is formed in the bottle body 2, and the fine uneven shapes 22, 23 are formed within the recess 52. In this case, by forming the covering sheets 50, 51 to close the open end of the recess 52, the fine uneven shapes 22, 23 can be covered with the covering sheets 50, 51. The covering sheets 50, 51 are preferably sheets made of the same resin as the raw material resin of the bottle body 2. This allows the bottle body 2 to be recycled or discarded without separating the covering sheets 50, 51 from the bottle body 2.

[0090] 15, the covering sheet 51 may be a sheet on which a fine uneven shape 53 similar to that of the decorative part 21 is formed. This allows light incident on the fine uneven shapes 22, 23 of the decorative part 21 to be diffracted, refracted, interfered with, or scattered, thereby effectively generating structural colors in the decorative part 21.

[0091] In the above embodiment, stretch blow molding was cited as an example of a method for forming the fine uneven shapes 22, 23 of the decorative portion 21, but other blow molding methods may be applied, such as extrusion blow molding, which blow molds a melt-extruded parison, or injection blow molding, which blow molds a bottomed parison formed by injection molding. For example, in the above embodiment, a manufacturing method and manufacturing conditions were described when the raw material resin was polyethylene terephthalate resin, but extrusion blow molding may be applied when the raw material resin is polyethylene resin or polypropylene resin.

[0092] The fine uneven shapes 22, 23 may also be formed by a method other than blow molding. For example, after the bottle body 2 is formed by blow molding following the steps of Figures 8A to 8F (where the mold body 41 does not have the transfer pattern 46), a plate on which the transfer pattern has been formed may be pressed by a thermal transfer technique, thereby transferring the transfer pattern to the outer surface 9 of the bottle body 2.

[0093] The embodiments of the present disclosure are to be considered as illustrative in all respects and not restrictive, and are intended to include modifications in all respects.

[0094] This application corresponds to Patent Application No. 2021-97800 filed with the Japan Patent Office on June 11, 2021, the entire disclosure of which is incorporated herein by reference. [Explanation of symbols]

[0095] 1: Bottle container 2: Bottle body 3: Cap 4: Mouth 5:Shoulder 6: Body 7: Bottom 8:Threaded part 9: External surface 10:Flat surface 11: Plastic panel 12: Separation rib 13: Upper part 14: Lower part 15:Flat surface 16: Plastic panel 17: Curved surface 18: Plastic panel 19: Plastic panel 20: Bottle Containment Room 21:Decorative part 21A: First decorative part 21B: Second decorative part 21C: Third decorative section 22: Uneven shape 23: Uneven shape 24: Convex part 25: Recess 26: Convex part 27: Recess 28: Preform 29: Preform molding machine 30: Cylinder 31: Extruder 32: Resin pellets 33: Hopper 34: Mold 35: Fixed side mold 36: Movable mold 37: Molten resin 38: Heater 39: Mold 40: Cavity surface 41: Mold body 42: Internal metal layer 43: Insulation section 44: Cavity 45: Cavity surface 46: Transcription pattern 47: Transfer section 48: Uneven shape 49: Arrow 50: Covering sheet 51: Covering sheet 52: Recess 53: Uneven shape 54: Plastic panel 55:Decoration area 56: Design Patterns 57: Air pressure 58 :Drag 59: Spring 60: Air cylinder 61: Through hole 62: Arrow H1: Height H2: Height P1: Pitch P2: Pitch P3: Pitch D1: Depth T1: Thickness

Claims

1. a bottle body having at least a mouth portion and a body portion provided below the mouth portion, the bottle body being formed of a single layer structure of a translucent resin, the translucent resin material being entirely exposed as an outer surface so that the presence or absence of contents can be visually confirmed; a decorative portion that is formed directly on the outer surface of the bottle body, which is an exposed surface of the translucent resin material, and includes a fine uneven shape that is exposed without being covered, and the exposed surface of the fine uneven shape exhibits a structural color, thereby partially decorating the outer surface of the bottle body; a functional film formed of a resin having a function different from that of the translucent resin forming the bottle body is not formed on the body portion so as to cover the entire periphery of the body portion; the minute concave-convex shape includes a plurality of quadrangular pyramidal convex portions arranged in a matrix and lattice-shaped concave portions between adjacent convex portions, a pitch of the fine unevenness, which is the distance between the tops of the adjacent convex portions, is 0.1 μm to 300 μm, and a height of the fine unevenness, which is the distance from the bottom surface of the concave portion to the top of the convex portion, is 0.1 μm to 300 μm; The bottle container, wherein the decorative portion is at least one of letters, illustrations, and marks formed by the fine uneven shape.

2. The bottle container according to claim 1 , wherein the translucent resin contains a colorless and transparent polyethylene terephthalate resin.

3. a first step of introducing a cylindrical translucent resin material into a cavity of a blow molding die including a pair of die bodies and a transfer portion formed on a cavity surface of at least one of the pair of die bodies and having a fine concave-convex pattern; a second step of molding a bottle body by expanding the translucent resin material introduced into the cavity by blow molding, and directly transferring the fine concave-convex pattern of the transfer portion onto the outer surface of the bottle body; a third step of removing the bottle body, the bottle body including a decorative portion that includes a fine uneven shape corresponding to the fine uneven pattern, and that partially decorates the outer surface by having an exposed surface of the fine uneven shape exhibit a structural color; the blow molding die includes a heat insulating part provided at a position facing the fine concave-convex pattern on the opposite side of the cavity with respect to the transfer part, the minute concave-convex shape includes a plurality of quadrangular pyramidal convex portions arranged in a matrix and lattice-shaped concave portions between adjacent convex portions, a pitch of the fine unevenness, which is the distance between the tops of the adjacent convex portions, is 0.1 μm to 300 μm, and a height of the fine unevenness, which is the distance from the bottom surface of the concave portion to the top of the convex portion, is 0.1 μm to 300 μm; A method for manufacturing a bottle container, wherein the decorative portion is at least one of letters, illustrations, and marks formed by the fine uneven shape.

4. 4. The method for manufacturing a bottle container according to claim 3, wherein the blow molding mold includes a mold body that forms the outer shape of the blow molding mold, an internal metal layer formed on the cavity surface, which is the inner surface of the mold body, and the heat insulating portion sandwiched between the mold body and the internal metal layer.

5. 5. The method for manufacturing a bottle container according to claim 3, wherein the second step includes a step of transferring the fine concave-convex pattern to the bottle body while applying a force to the transfer unit that resists the pressure of air introduced into the bottle body during the blow molding.

6. 5. The method for manufacturing a bottle container according to claim 3, wherein the second step includes a step of transferring the fine concave-convex pattern to the bottle body while discharging remaining air in the cavity to the outside of the mold body during the blow molding.

7. The method for manufacturing a bottle container according to claim 3 or 4, wherein the translucent resin material includes a colorless and transparent polyethylene terephthalate resin material.

8. The method for manufacturing a bottle container according to claim 3 or 4, wherein the first step includes a step of setting a preform having a bottom in the blow molding die.

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