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WO2025022687A1 - Réceptacle en papier, réceptacle en papier à étanchéité supérieure et procédé de fabrication de réceptacle en papier - Google Patents

Réceptacle en papier, réceptacle en papier à étanchéité supérieure et procédé de fabrication de réceptacle en papier Download PDF

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Publication number
WO2025022687A1
WO2025022687A1 PCT/JP2023/047012 JP2023047012W WO2025022687A1 WO 2025022687 A1 WO2025022687 A1 WO 2025022687A1 JP 2023047012 W JP2023047012 W JP 2023047012W WO 2025022687 A1 WO2025022687 A1 WO 2025022687A1
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WIPO (PCT)
Prior art keywords
paper container
wrinkles
paper
container
flange portion
Prior art date
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Pending
Application number
PCT/JP2023/047012
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English (en)
Japanese (ja)
Inventor
隆昌 篠原
浩史 山崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyo Aluminium Ekco Products Co Ltd
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Toyo Aluminium Ekco Products Co Ltd
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Filing date
Publication date
Application filed by Toyo Aluminium Ekco Products Co Ltd filed Critical Toyo Aluminium Ekco Products Co Ltd
Publication of WO2025022687A1 publication Critical patent/WO2025022687A1/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Rigid or semi-rigid containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material or by deep-drawing operations performed on sheet material
    • B65D1/22—Boxes or like containers with side walls of substantial depth for enclosing contents
    • B65D1/26—Thin-walled containers, e.g. formed by deep-drawing operations
    • B65D1/28—Thin-walled containers, e.g. formed by deep-drawing operations formed of laminated material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Rigid or semi-rigid containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material or by deep-drawing operations performed on sheet material
    • B65D1/34—Trays or like shallow containers

Definitions

  • This invention relates to paper containers, top-sealed paper containers, and methods for manufacturing paper containers, and in particular to paper containers, top-sealed paper containers, and methods for manufacturing paper containers that are formed solely by press molding from a single sheet of paperboard base paper.
  • Figure 8 is a perspective view showing the external shape of a conventional paper container shown in Japanese Patent Application Laid-Open No. 10-43027.
  • the paper container 51 is composed of a bottom 52 having a generally rectangular shape with rounded corners, a side wall 53 connected to the periphery of the bottom 52 and rising diagonally upward, a flange 54 connected to the upper end of the side wall 53 and extending horizontally, and a rolled rim 55 connected to the outer periphery of the flange 54.
  • the corners of the side wall 53 and the flange 54 are side wall corners 57 and curved flanges 58, which have multiple wrinkles 56 formed radially from the inside to the periphery.
  • Figure 9 is a plan view showing the overall shape of the paperboard base paper used to press-mold the paper container shown in Figure 8.
  • the paperboard base paper 70 has a generally rectangular shape with rounded corners, with its central portion 72 corresponding to the bottom portion 52 of the paper container, and its outer periphery 73 corresponding to the side wall portion 53, flange portion 54 and rolled edge portion 55 of the paper container 51. Note that a number of radially extending lines 71 are formed in the portions of the outer periphery 73 that correspond to the side wall corner portions 57 and curved flange portions 58 at the four corners.
  • wrinkles 56 are formed in the press-molded paper container 51 as described above, even if the formation of wrinkles 56 can be controlled regularly by forming multiple lines 71 in the paperboard base paper 70 and press-molding it, the wrinkles 56 themselves will end up with unevenness.
  • JP Patent Publication 2000-33927 discloses a technology for deep-drawn paper containers that have a flange using paperboard base paper with a thermoplastic resin layer laminated on one side of the paperboard, and then form the flange into a smooth surface using ultrasonic processing, crushing the flange using heat and pressure from the ultrasonic processing to form a smooth surface with few irregularities, resulting in a highly airtight deep-drawn paper container with a top seal.
  • Figure 10 shows how the lines formed on the paperboard base paper change during the manufacture of paper containers, with (1) showing the state before the pressing process, (2) after the pressing process, (3) after the wrinkle pressing process using ultrasonic processing, and (4) after top-seal packaging.
  • a resin layer (not shown) is formed on the inner surface of the paperboard base paper 80, and the paperboard base paper 80 is folded from the inner surface to the outer surface of the container to form lines 81. That is, recesses 82 and protrusions 83 of the lines 81 are formed on the inner surface and outer surface of the container, respectively.
  • the resin layer on the surface of the wrinkles 86 on the inside surface of the container melts and becomes a fusion layer that attempts to fuse together. This makes it possible to flatten to a certain extent the unevenness that has occurred in the wrinkles 86 in the flange portion.
  • the wrinkles 86 formed on the side wall and flange are formed by folding from the inner surface to the outer surface of the paper container.
  • the wrinkles 86 are formed in this way, even if the wrinkles 86 of the flange are flattened by crushing them using heat and pressure from ultrasonic processing as in Patent Document 2, the fine spaces 84 on the inner side of the wrinkles 86 cannot be completely melted and fused, and voids 85 remain inside the wrinkles 86.
  • This invention was made to solve the above problems, and aims to provide a paper container with high top sealing properties, a top-sealed paper container, and a method for manufacturing a paper container.
  • the paper container in the first aspect of the present invention is a paper container formed solely by press molding from a sheet of paperboard base paper with a resin layer formed on at least the surface that will become the inside surface of the container, and has a bottom, a side wall connected to the bottom, and a flange connected to the upper end of the side wall and extending horizontally outward, the side wall and the flange have a number of creases formed by press molding, the creases in the flange are formed by folding from the lower surface to the upper surface of the flange, and the creases that appear on the upper surface of the flange have at least a partially flat portion.
  • This configuration achieves effect 1, in that the flange portion is flattened and the presence or absence of minute gaps on the inside side of the wrinkles does not affect the top seal.
  • the paper container in the second aspect of the invention has the same configuration as the first aspect of the invention, but has a rolled edge on the outer periphery of the flange, and the highest part of the rolled edge is located at the same height as or below the top surface of the flange.
  • the paper container in the third aspect of the present invention is one in which, in the configuration of the invention in the first or second aspect, the ratio (S1/S2) of the cross-sectional thickness of the wrinkled paper container having a flat portion (S1) to the cross-sectional thickness of the wrinkled paper container having no flat portion (S2) is 0.7 or less.
  • This configuration achieves effect 3, in which wrinkles with flat portions are reliably flattened compared to wrinkles that do not have flat portions.
  • the paper container has the configuration of the invention in the first or second aspect, in which the wrinkles in the flange portion are formed based on a plurality of lines formed in the portion of the paperboard base paper that corresponds to the flange portion.
  • This configuration achieves effect 4, in which irregular wrinkles that tend to occur during press molding are absorbed by the creases.
  • the paper container has the configuration of the invention in the first or second aspect, and the wrinkles in the side wall portion are formed by folding from the inner surface of the side wall portion to the outer surface.
  • the concave portions of the creases are located on the inner side of the side wall, and the creases that fold from the inner surface of the paper container to the outer surface only extend to the upper part of the side wall. This results in effect 5, where even if capillary action occurs due to minute gaps inside the creases, moisture, etc. absorbed by capillary action only reaches the upper part of the side wall and does not reach the flange.
  • the top-sealed paper container in the sixth aspect of the present invention is a top-sealed paper container that is composed of the paper container in the first or second aspect and a lid material that has top-sealing properties.
  • This configuration provides effect 6, which is that the flange portion is top sealed without leakage.
  • the method for manufacturing a paper container in a seventh aspect of the present invention includes a preparation step of preparing paperboard base paper, a pressing step of pressing the paperboard base paper to form a paper container having a bottom, a side wall portion connected to the bottom, and a flange portion connected to the upper end of the side wall portion, extending horizontally outward, and having wrinkles formed on the upper surface by folding from the bottom surface to the top surface, and a wrinkle pressing step of forming flat portions on at least some of the wrinkles.
  • effect 7 is achieved, which is that the flange portion is flattened and a paper container is obtained in which the presence or absence of minute gaps on the inside side of the wrinkles does not affect the top seal.
  • the eighth aspect of the present invention is a method for manufacturing a paper container, in which the wrinkle pressing step in the configuration of the seventh aspect of the invention includes ultrasonic processing of the wrinkles.
  • This configuration provides effect 8, which makes it easier to flatten the flange portion.
  • the method for manufacturing a paper container in a ninth aspect of the present invention is the same as the eighth aspect of the invention in that a resin layer is formed on at least the surface of the paperboard base paper that will become the inside surface of the container, and the resin layer is melted by ultrasonic processing.
  • the method for manufacturing a paper container in a tenth aspect of the present invention is the same as the ninth aspect of the invention, in which the wrinkle pressing step reduces the cross-sectional thickness of the wrinkled paper container having flat portions by ultrasonic processing to 70% or less, compared to 100% of the cross-sectional thickness of the wrinkled paper container before ultrasonic processing.
  • This configuration achieves effect 10, which is that a paper container is obtained in which the wrinkles in the flange portion are reliably flattened compared to the wrinkles before ultrasonic processing.
  • the top-sealed paper container in an eleventh aspect of the present invention is the same as the sixth aspect of the invention, except that the paper container and the lid are provided with a resin layer with barrier properties.
  • This configuration provides the effect 11 of top sealing the flange without leakage.
  • the paper container in the first aspect of the present invention achieves the above-mentioned effect 1, and therefore becomes a paper container with improved top sealing properties when top sealing is performed using a lid material such as a top seal film.
  • the strength is improved compared to conventional paper containers in which wrinkles are not flattened.
  • the paper container in the second aspect of the present invention provides the effect 2 described above in addition to the effect of the first aspect of the invention, making it easier to attach the lid material and improving yield.
  • the paper container in the third aspect of the present invention provides the above-mentioned effect 3 in addition to the effects of the invention in the first or second aspect, and therefore further improves the top sealability when top sealing is performed using a top seal film.
  • the paper container in the fourth aspect of the present invention provides the above-mentioned action 4 in addition to the effects of the invention in the first or second aspect, so when top sealing is performed using a top seal film, there is less variation in the quality of the top sealability and the aesthetics are improved.
  • the paper container in the fifth aspect of the present invention provides the above-mentioned effect 5 in addition to the effects of the invention in the first or second aspect, improving ease of eating, and when top sealing is performed using a top seal film, achieving both good top sealability and ease of eating.
  • the top-sealed paper container in the sixth aspect of the present invention achieves the above-mentioned effect 6, thereby improving the sealing performance of the top-sealed paper container.
  • the paper container manufacturing method according to the seventh aspect of the present invention achieves the above-mentioned effect 7, and therefore when top sealing is performed using a top seal film, a paper container with improved top sealability is obtained.
  • the paper container manufacturing method according to the eighth aspect of the present invention achieves the effect of the seventh aspect of the invention as well as the above-mentioned effect 8, thereby improving the productivity of paper containers.
  • the method for manufacturing a paper container in the ninth aspect of the present invention provides the above-mentioned effect 9 in addition to the effect of the invention in the eighth aspect, so that when top sealing is performed using a top seal film, a paper container with further improved top sealability is obtained.
  • the method for manufacturing a paper container in the tenth aspect of the present invention provides the above-mentioned action 10 in addition to the effect of the invention in the ninth aspect, so that when top sealing is performed using a top seal film, a paper container with further improved top sealability is obtained.
  • the top-sealed paper container in the eleventh aspect of the present invention provides the above-mentioned action 11 in addition to the effect of the invention in the sixth aspect, thereby improving the sealing of the top-sealed paper container and providing a top-sealed paper container with high gas barrier properties.
  • FIG. 1 is a plan view showing the overall shape of a paper container according to an embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing the overall structure of the paper container shown in FIG. 1 .
  • 2 is a plan view showing the overall shape of a paperboard base paper for press-molding the paper container shown in FIG. 1.
  • FIG. FIG. 4 shows how the lines formed on the paperboard base paper shown in FIG. 3 change during the manufacture of a paper container, in which (1) is the state before the pressing process, (2) is the state after the pressing process, (3) is the state after the wrinkle pressing process using ultrasonic processing, and (4) is the state after top-seal packaging.
  • FIG. 2 is a schematic cross-sectional view showing a wrinkle pressing step in the manufacturing method of the paper container shown in FIG. 1.
  • FIG. 2 is a schematic diagram showing a measurement test for the paper container shown in FIG. 1 .
  • 7 is a graph showing the results of the measurement test shown in FIG. 6, where (1) is the longitudinal direction and (2) is the transverse direction.
  • FIG. 1 is a perspective view showing the external shape of a conventional paper container shown in Patent Document 1.
  • FIG. 9 is a plan view showing the overall shape of a paperboard base paper for forming the paper container shown in FIG. 8 by press molding.
  • FIG. 1 shows how the lines formed on the paperboard base paper change during the manufacture of a paper container, with (1) showing the state before the pressing process, (2) showing the state after the pressing process, (3) showing the state after the wrinkle pressing process using ultrasonic processing, and (4) showing the state after top-seal packaging.
  • FIG. 1 is a plan view showing the overall shape of a paper container according to an embodiment of the present invention
  • FIG. 2 is a cross-sectional view showing the overall structure of the paper container shown in FIG. 1.
  • the paper container 1 is composed of an oval bottom 2, a side wall 3 connected to the bottom 2, a flange 4 connected to the upper end of the side wall 3 and extending horizontally outward, and a rolled edge 5 connected to the outer periphery of the flange 4.
  • a number of wrinkles 6 are formed around the entire circumference of the side wall 3, flange 4, and rolled edge 5 of the paper container 1, extending radially toward the outer periphery. Details of the wrinkles 6 will be described later.
  • the rolled edge portion 5 is located downward from the outer periphery of the flange portion 4, and the end of the rolled edge portion 5 is formed so as to be rolled into the inside of the rolled edge portion 5, and is formed along the entire outer periphery of the flange portion 4, so that the cross section of the rolled edge portion 5 is formed in a ring shape.
  • the highest part of the ring shape of the rolled edge portion 5 is formed so as to be at the same height as the upper surface of the flange portion 4.
  • the rolled edge portion 5 is not positioned so as to protrude above the upper surface of the flange portion 4 on the outward extension of the mounting surface of the lid material. Therefore, when a lid material, particularly a lid material such as a top seal film, is used for top sealing, the rolled edge portion 5 does not get in the way during top sealing, making top sealing easier, which makes it easier to attach the lid material and improves yield.
  • Figure 3 is a plan view showing the overall shape of the paperboard base paper used to press-mold the paper container shown in Figure 1.
  • the paperboard base paper 10 is made by punching out a sheet body with resin layers formed on both sides of a paper base material by an extrusion lamination method, and has an oval shape.
  • the central part of the paperboard base paper 10 is a bottom corresponding part 12 that corresponds to the bottom 2 of the paper container 1, and on its outer periphery are a side wall corresponding part 13, a flange corresponding part 14, and a edge corresponding part 15 that correspond to the side wall part 3, flange part 4, and edge roll part 5 of the paper container 1.
  • the side wall portion 13, the flange portion 14, and the edge roll portion 15 have multiple radially extending lines 21 formed on them.
  • Figure 4 shows how the lines formed on the base paper shown in Figure 3 change during the manufacture of paper containers, with (1) showing the state before the pressing process, (2) after the pressing process, (3) after the wrinkle pressing process using ultrasonic processing, and (4) after top-seal packaging.
  • the paperboard base paper 10 is prepared.
  • the lines 21 formed on the paperboard base paper 10 are folded from the inner surface side of the container to the outer surface side of the container. That is, the convex portions 23 and the concave portions 22 of the lines 21 are formed on the inner surface side and the outer surface side of the container, respectively.
  • a paper container 1 is formed from the paperboard base paper 10, which includes a bottom 2, a side wall portion 3 connected to the bottom 2, and a flange portion 4 connected to the upper end of the side wall portion 3, extending horizontally outward, and having wrinkles 6 formed by folding from the lower surface to the upper surface.
  • the lines 21 absorb and compress the irregular wrinkles that tend to occur during press molding. This improves the aesthetics of the paper container 1. Furthermore, by being able to prevent the occurrence of irregular wrinkles in the flange portion 4, when top sealing is performed using a top seal film on the flange portion 4, there is less variation in the quality of the top sealability.
  • wrinkles 6 are formed in the side wall 3 and flange 4 of the paper container 1 after the pressing process, centered on the convex portion 23 on the inside surface of the container.
  • wrinkles 6 are formed by folding in a direction from the bottom surface of the flange 4 to the top surface.
  • the outer peripheral edge of the flange portion 4 is rolled to form the rolled portion 5 around the entire circumference.
  • the rolled portion 5 is formed in a ring shape on the outer peripheral edge of the flange portion 4, and the upper end of the rolled portion 5 (the part with the highest height) is located above the upper surface of the flange portion 4.
  • the wrinkles 6 in the flange portion 4 are further compressed using ultrasonic processing.
  • Figure 5 is a schematic cross-sectional view showing the wrinkle pressing process in the paper container manufacturing method shown in Figure 1.
  • the paper container 1 is placed on the base 41 of the ultrasonic processing device, and the ultrasonic horn 42 is lowered from above the paper container 1 to sandwich the flange portion 4 of the paper container 1 between the base 41 and the ultrasonic horn 42. Then, pressure is applied from above and below while applying a predetermined ultrasonic vibration. This causes the resin layer of the flange portion 4 to be locally heated by the ultrasonic processing. As the resin layer has thermoplasticity, the folded portion along with the lines 21 melts and becomes a fused layer that fuses together. When pressed in this state, the wrinkles 6 in the flange portion 4 are generally flattened.
  • the portion of the base 41 of the ultrasonic processing device that corresponds to the rolled edge portion 5 is cut out, and the surface of the ultrasonic horn 42 that comes into contact with the paper container 1 is flat, including the portion that corresponds to the rolled edge portion 5. Therefore, when the ultrasonic horn 42 is lowered to the top surface of the flange portion 4, the highest part of the rolled edge portion 5, which was located above the top surface of the flange portion 4, is pushed downward by the ultrasonic horn 42.
  • the rolled edge portion 5 is not crushed even by the pressure from the ultrasonic horn 42, and as the ultrasonic horn 42 descends, the rolled edge portion 5 is pushed down to the same height as the top surface of the flange portion 4. In this way, the paper container 1 shown in Figure 1 is manufactured.
  • the ultrasonic processing was performed by placing the paper container 1 so that the ultrasonic horn 42 was in contact with the upper surface of the flange portion 4 as shown in FIG.
  • the wrinkles 6 are heated by ultrasonic processing while being pressed. Then, the gaps 26a, 26b are closed, and the resin layer around the gaps 26a, 26b melts and becomes a fusion layer, which fuses to each other so as to fill the gaps 26a, 26b, forming a pair of gap marks 27a, 27b. As a result, the wrinkles 6 are flattened, and a flat portion 28 is formed between the pair of gap marks 27a, 27b on the inner surface side of the container (upper surface of the flange portion 4).
  • the flat portion 28 refers to the surface portion of the crushed wrinkles 7 formed on the inner surface side of the container (upper surface of the flange portion 4) when the wrinkles 6 are crushed through a process of pressing the wrinkles such as ultrasonic processing.
  • flat refers to a state in which there is no change in height such as unevenness as a whole to the extent that the top seal is not hindered.
  • a flat portion is formed on at least a part of the upper part of the wrinkles 6.
  • the resin layer on the surface of the wrinkles 6 on the outer surface of the container melts to form a fusion layer, and the adjacent surrounding resin layers fuse to each other, flattening the wrinkles 6 on the outer surface of the container to some extent.
  • the space 24 is considerably larger than the gaps 26a and 26b, the space 24 inside the wrinkles 6 cannot be completely eliminated, and a gap 25 remains inside the wrinkles 6 (crushed wrinkles 7).
  • the flange portion 4 is flattened, the strength is improved compared to conventional paper containers in which the wrinkles are not flattened.
  • the wrinkle pressing process includes ultrasonic processing of the wrinkles, it becomes easier to flatten the flange portion, and the productivity of the paper container is improved.
  • the paper container has an oval outer edge, but the shape is not particularly limited as long as it is a paper container with a flange.
  • the shape when viewed from above the container opening can be a circle, a square, a polygon, or a roughly ellipse that includes straight lines.
  • the size of the container can also include one with a partition on the inside.
  • the multiple wrinkles formed by press molding are formed based on the multiple lines formed in the paperboard base paper, but the same effects of improving strength and top sealability can be achieved even if the paperboard base paper does not have lines formed in advance.
  • the wrinkles appearing on the upper surface of the flange portion have flat portions formed from the end of the upper surface of the flange portion on the side wall side to the end on the rolled edge side, but it is sufficient that a flat portion is formed on at least a portion of the end from the end on the side wall side to the end on the rolled edge side. Also, it is acceptable for flat portions to be formed only on some of the multiple wrinkles appearing on the upper surface of the flange portion, with no flat portions formed on the other wrinkles.
  • the outer edge of a paper container is oval in shape, it is possible to improve the container strength in the longitudinal direction by forming flat portions only on the wrinkles of the flange portion in the longitudinal direction, and in this way it is also possible to improve the strength in a specific direction or area.
  • the flat portion is formed around the entire circumference of the flange portion, but it is sufficient that it is formed on at least a part of the flange portion. It may also be formed on the side wall portion. In other words, ultrasonic processing may be performed on the side wall portion (wrinkles).
  • the ratio of the paper container cross-sectional thickness (S1) of the wrinkles having flat portions to the paper container cross-sectional thickness (S2) of the wrinkles having no flat portions is 0.7 or less.
  • the flange portion extends horizontally, but the horizontal direction does not only mean the horizontal direction when the paper container is placed on a horizontal surface, but also includes cases where the flange extends diagonally upwards or downwards toward the horizontal direction. Also, it includes unavoidable errors due to the molding process and the characteristics of the paper.
  • the highest part of the rolled edge is located at the same height as the upper surface of the flange, but it may be located above or below the upper surface of the flange.
  • the paper container has a rolled edge, but the paper container may not have a rolled edge.
  • the wrinkles in the side wall portion are formed by folding from the outer surface of the container to the inner surface of the container, but they may be formed by folding from the inner surface to the outer surface.
  • the paperboard base paper may have a portion where the lines corresponding to the wrinkles in the side wall portion and the lines corresponding to the wrinkles in the flange portion are not connected.
  • the concave parts of the wrinkles are located on the inner side of the side wall. Then, when food is placed inside and eaten with a spoon or the like, there are no convex parts of the wrinkles on the inner side, so the spoon or the like does not get caught on the convex parts of the wrinkles on the inner side of the container. Also, since the wrinkles that are folded from the inner side to the outer side of the paper container only extend to the upper part of the side wall, even if capillary action occurs due to minute gaps inside the wrinkles, moisture etc. absorbed by capillary action only reaches the upper part of the side wall and does not reach the flange. This makes it possible to achieve both good top sealing properties and ease of eating.
  • the top seal is performed using a lid material such as a top seal film, but a lid material made of paper, plastic, or metal such as aluminum may also be fitted.
  • the container may be shrink-wrapped.
  • the type, configuration, and sealing mode are not particularly limited as long as the paper container can be sealed by sealing with the top seal film that serves as the lid material, and it does not matter whether the top seal film is a complete seal type or an easy peel type.
  • a top seal film with known heat sealability that is widely used can also be used. Therefore, the top seal film may be a film made of a single layer of resin as long as it has sealing properties, or it may be a film in which not only a single layer but also multiple layers of resin are laminated in order to provide heat resistance and barrier properties.
  • a top seal film with high gas barrier properties is used as the lid material for the paper container of the present invention, it is possible to produce a top seal paper container with high gas barrier properties.
  • the resin used for the top seal film is not particularly limited, but examples thereof include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin resins such as polypropylene, polyethylene, and polymethylpentene, polyamide resins such as nylon, acrylic (methacrylic) resins, diene resins such as polybutadiene, and thermoplastic resins such as polycarbonate resins.
  • polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate
  • polyolefin resins such as polypropylene, polyethylene, and polymethylpentene
  • polyamide resins such as nylon
  • acrylic (methacrylic) resins diene resins
  • diene resins such as polybutadiene
  • thermoplastic resins such as polycarbonate resins.
  • the resin when used as a top seal film for a food packaging container, it is more preferable that the resin has heat resistance that can withstand high-temperature heating in an oven or microwave oven.
  • a resin with such a barrier property can be laminated with a film or coating.
  • the type of resin with barrier properties is not particularly limited, and examples thereof include polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer resin, polyvinylidene chloride resin, etc.
  • a metal vapor deposition film such as aluminum or an inorganic vapor deposition film such as silica or alumina formed on the surface of a polyethylene terephthalate or polypropylene film can also be used for the purpose of imparting barrier properties.
  • a top seal film may be formed by combining and laminating a plurality of the above-mentioned various resins.
  • a top seal film in which at least a polyolefin resin such as polypropylene or polyethylene or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate is laminated with a resin with high gas barrier properties such as an ethylene-vinyl alcohol copolymer resin or a polyvinyl alcohol resin can be exemplified.
  • a top seal film in which at least an ethylene-vinyl alcohol copolymer resin is laminated on polyethylene terephthalate it is preferable because it is possible to impart high gas barrier properties and to obtain a top seal paper container with high heat resistance when the paper container of the present invention is top sealed.
  • the sealant layer may be formed from a known sealant film, or from an adhesive such as a lacquer-type adhesive, an easy-peel adhesive, or a hot-melt adhesive.
  • the thickness of such a top seal film is not particularly limited, but examples include those with a thickness of about 5 ⁇ m to 200 ⁇ m. Preferably, the thickness is about 20 ⁇ m to 80 ⁇ m.
  • the type of paper used for the paperboard base paper in the paper container of the present invention is not particularly limited, but for example, pure white roll paper, kraft paper, coated cardboard, parchment paper, ivory paper, Manila paper, card paper, cup paper, glassine paper, etc., as well as paperboard or synthetic paper that has been treated to be water-resistant or oil-resistant, etc. can be used, and the desired material can be selected depending on the application.
  • a resin film can be attached to the paperboard, or a combination of resin extrusion by extrusion lamination, resin-coated paperboard, etc. can be used.
  • At least one side of the paperboard (the side that comes into contact with food) has a resin layer formed by extrusion lamination, and it is even more preferable to use one with a resin layer formed on both sides.
  • the thickness of the paperboard base paper is not particularly limited, but one having a thickness of about 0.1 to 0.5 mm (basis weight 100 to 500 g/m 2 ) can be preferably used.
  • the wrinkles in the flange portion of the paper container of the present invention are flattened by ultrasonic processing or the like, the strength of the flange portion is improved, and the resistance of the entire container to deformation is increased. Therefore, it is possible to form a paperboard base paper having a thickness thinner than conventional paperboard base paper, and even when such a thin paperboard is used, it is possible to ensure strength comparable to conventional paperboard.
  • the interlayer strength of the paperboard base paper is preferably 500 mN/cm or more, more preferably 700 mN/cm or more, in the case of the T-peel method.
  • the test method according to the internal bond tester method JAPAN TAPPI No. 18-2 "Paper and paperboard-Internal bond strength test method-Part 2: Internal bond tester method"
  • it is preferably 200 J/ m2 or more, more preferably 290 J/m2 or more . Since the paperboard base paper usually used for forming paper containers is composed of multiple pulp layers by papermaking, if the interlayer strength is low, delamination between the pulp layers is likely to occur and buckling during forming is likely to occur.
  • the interlayer strength of the paperboard base paper is 500 mN/cm or more in the case of the T-peel method or 200 J/m2 or more in the case of the internal bond tester method, buckling of the paperboard base paper during forming of the paper container, particularly buckling of the paperboard base paper during the formation of the edge roll, can be suppressed.
  • the interlaminar strength of the paperboard base paper is preferably 1500 mN/cm or less, more preferably 1000 mN/cm or less.
  • the internal bond tester method it is preferably 800 J/m2 or less, more preferably 500 J/ m2 or less.
  • the interlaminar strength refers to the peel resistance strength between each of the first and second layers and between the second and third layers.
  • the paperboard base paper has a predetermined folding resistance.
  • the paper is likely to tear in the side wall of the paper container, especially in the corners where many wrinkles are gathered. This is because the part of the paperboard base paper that corresponds to the corner is folded three-dimensionally in the vertical direction by a mold during press molding, and external forces act from multiple directions to form multiple wrinkles. Therefore, the paperboard base paper used in this example is designed to have a folding resistance of 800 to 2000 times in both the vertical and horizontal directions, measured in accordance with JIS P8115 (2001) "Test method for folding resistance of paper and paperboard using an MIT tester".
  • the folding resistance is 1000 to 1800 times.
  • paperboard base paper that has a folding resistance of less than 800 times, there is a risk that the paper will tear when the side wall of the paper container, especially the corners, are molded during press molding.
  • paperboard base paper that can withstand more than 2,000 folds, the paper has too strong a tendency to be folded, making it prone to springback at the rolled edges after press molding, which can reduce the shape retention of the paper container.
  • a resin film or coating may be laminated on the surface of the paperboard base paper.
  • the type of resin is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polypropylene, polyethylene, and polymethylpentene, acrylic (methacrylic) resins, diene resins such as polybutadiene, and thermoplastic resins such as polycarbonate resins.
  • thermoplastic resins produced as biomass resins derived from living organisms and biodegradable resins such as polybutylene succinate (PBS) and polylactic acid (PLA) can also be used.
  • PBS polybutylene succinate
  • PLA polylactic acid
  • the thermoplastic resin is suitable for ultrasonic processing after the paper container is formed, and it is more preferable that the thermoplastic resin has heat resistance that can withstand high-temperature heating in an oven or microwave oven when used as a food packaging container.
  • a resin having such a barrier property can be laminated in the form of a film or coating.
  • the type of resin having a barrier property is not particularly limited, and examples thereof include polyvinyl alcohol resin (PVA), ethylene-vinyl alcohol copolymer resin (EVOH), polyvinylidene chloride resin (PVDC), etc.
  • a film having a metal vapor deposition film such as aluminum or an inorganic vapor deposition film such as silica or alumina formed on the surface of a polyethylene terephthalate or polypropylene film can also be used for the purpose of imparting a barrier property.
  • a combination of a plurality of the above-mentioned various resins may be laminated on the surface of the paperboard base paper.
  • a plurality of resins can be laminated in order from the surface of the paperboard base paper, such as a polyolefin-based resin such as polypropylene or polyethylene or a polyester-based resin such as polyethylene terephthalate or polybutylene terephthalate as the first resin layer, a resin having high gas barrier property such as an ethylene-vinyl alcohol copolymer resin or a polyvinyl alcohol resin as the second resin layer, and a polyolefin-based resin or polyester-based resin as the third resin layer, similar to the first layer.
  • a polyolefin-based resin such as polypropylene or polyethylene
  • a polyester-based resin such as polyethylene terephthalate or polybutylene terephthalate
  • a resin having high gas barrier property such as an ethylene-vinyl alcohol copolymer resin or a polyvinyl alcohol resin as the second resin layer
  • a polyolefin-based resin or polyester-based resin as the third resin layer, similar to
  • the laminated structure is preferable because it can impart high gas barrier properties to the paper container, has high heat resistance, is easy to process, and has low raw material costs.
  • this does not exclude laminating other resins or other structures (e.g., metal foils such as aluminum foil) in this structure.
  • methods for forming the resin layer include extrusion lamination, dry lamination, wet lamination, and coating of a resin solution. By laminating the resin, it is possible to impart properties such as heat resistance, water resistance, and gas/liquid permeability resistance to the paper container after molding.
  • a method can be adopted in which a gas barrier resin film is prepared in advance, and when another resin layer is extrusion laminated on the surface of the paperboard base paper, the gas barrier resin film is laminated on the resin layer.
  • a method can be adopted in which multiple resin layers can be formed on the surface of the paperboard base paper without using a separate adhesive.
  • a first resin layer is a polyolefin resin such as polypropylene or polyethylene, or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate
  • a second resin layer is a resin with high gas barrier properties such as an ethylene-vinyl alcohol copolymer resin or a polyvinyl alcohol resin
  • a third resin layer is a polyolefin resin or polyester resin similar to the first layer
  • a gas barrier resin film in which the second and third resin layers are laminated is prepared in advance, and when a polyolefin resin such as polypropylene or polyethylene, or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate is extrusion laminated as the first resin layer on the surface of the paperboard base paper, this gas barrier resin film is laminated on the first resin layer, thereby making it possible to easily impart gas barrier properties to
  • the thickness of the resin on the surface of the paperboard base paper is not particularly limited, but may be, for example, in the range of 10 ⁇ m to 50 ⁇ m. Particularly preferably, it is in the range of 20 ⁇ m to 30 ⁇ m. However, as described above, when multiple resin layers are laminated as the resin layer, it may exceed this range. For example, when multiple resin layers are laminated, the total thickness may be in the range of 10 ⁇ m to 200 ⁇ m, particularly preferably 30 ⁇ m to 100 ⁇ m, and even more preferably 50 ⁇ m to 70 ⁇ m. Within this range, the desired effect of forming the resin layer can be imparted.
  • the unevenness of the paper is less likely to appear on the surface of the flange portion, which also contributes to further flattening the flange portion. If the thickness of the resin layer is below this range, the desired effect of forming the resin layer may not be expected, and if the thickness of the resin layer is above this range, the cost will be high. Furthermore, if the total thickness of multiple laminated resin layers exceeds 200 ⁇ m, it may no longer be considered a paper container due to the thickness or weight of the paperboard base paper.
  • the surface of the paperboard base paper may be printed, which can improve the design.
  • creases are formed around the entire circumference of the parts corresponding to the side wall parts, flange parts, and rolled edges, but it is sufficient that the creases are formed around at least a part of the side wall parts and flange parts. Also, creases do not have to be formed.
  • the wrinkle pressing process be such that the cross-sectional thickness of the wrinkled paper container having flat portions due to ultrasonic processing is 70% of the cross-sectional thickness of the wrinkled paper container before ultrasonic processing, compared to 100% of the cross-sectional thickness of the wrinkled paper container before ultrasonic processing.
  • paper containers according to the embodiments of the present invention are manufactured using a specific manufacturing method, they may be manufactured using other manufacturing methods.
  • the flange portion of the paper container is manufactured by pressing the wrinkles using ultrasonic processing to form a flat portion
  • the manufacturing method may be one in which the flat portion is formed by pressing using a method other than ultrasonic processing.
  • Test specimens of the examples and comparative examples of the present invention were prepared, and a wrinkled paper container cross-section thickness measurement test was conducted on these test specimens to compare the thickness of the wrinkled paper container cross-section, an air leakage test was conducted to evaluate the adhesion of the top seal, and a strength measurement test was conducted to measure the strength of the paper container.
  • a paperboard base paper with resin layers formed on both sides and with lines formed in the side wall portion corresponding portion, the flange portion corresponding portion, and the rolled edge corresponding portion was prepared (preparation step), and this paperboard base paper was press molded to form a paper container (press step).
  • the paperboard base paper had a paperboard thickness of about 0.3 mm and a basis weight of about 260 g/ m2 , and was extrusion laminated with about 20 ⁇ m of polypropylene resin on each side.
  • the size of the paper container was about 179 mm in the long side direction (including the flange portion) and about 120 mm in the short side direction (including the flange portion) in plan view, about 30 mm in height from the bottom to the flange portion, and about 3 mm in diameter of the rolled edge portion.
  • the lines of the paperboard base paper are formed by folding from the outer surface of the container to the inner surface of the container, wrinkles are formed in the side walls and flanges of the paper container after press molding, as if they are folded from the outer surface of the container (the bottom surface of the flange) to the inner surface of the container (the top surface of the flange) (hereinafter, the state in which wrinkles are formed by folding from the outer surface of the container to the inner surface of the container is referred to as ⁇ reverse grain'').
  • Example 1 the paper container after press molding (after the pressing process) was placed on the base of an ultrasonic processing device as shown in Figure 5, an ultrasonic horn was lowered from above the paper container, the flange part of the paper container was sandwiched between the base and the ultrasonic horn, ultrasonic vibrations of 3.0 kW were applied to the flange part for 0.5 seconds, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles from above and below (wrinkle pressing process).
  • This paper container was designated as Example 1.
  • Example 2 A paper container was press-molded in the same manner as in Example 1, and ultrasonic vibrations of 3.0 kW were applied to the flange portion for 1.0 second using the same ultrasonic processing device as in Example 1, applying a pressure of 0.4 MPa/ cm2 to crush wrinkles from above and below.
  • This paper container was designated Example 2.
  • Example 3 A paper container was press-molded in the same manner as in Example 1, and ultrasonic vibrations of 3.0 kW were applied to the flange portion for 1.5 seconds using the same ultrasonic processing device as in Example 1, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles from above and below.
  • This paper container was designated Example 3.
  • Example 4 instead of the paperboard base paper used in Example 1, a paperboard base paper with a thickness of about 0.3 mm and a basis weight of about 260 g/ m2 was used, in which about 20 ⁇ m of polypropylene resin was extrusion laminated on one side of the paperboard base paper and about 20 ⁇ m of polypropylene resin was laminated on the other side, in that order from the surface of the paperboard base paper, as a first resin layer, about 20 ⁇ m of polypropylene resin, as a second resin layer, about 20 ⁇ m of ethylene-vinyl alcohol copolymer resin, and as a third resin layer, about 20 ⁇ m of polypropylene resin, was laminated on the other side.
  • a paper container was press-molded in the same manner as in Example 1 so that the side of the paperboard base paper on which only the polypropylene resin was formed was the outer surface of the container, and ultrasonic vibrations of 3.0 kW were applied to the flange part for 1.0 second using the same ultrasonic processing device as in Example 1 to apply a pressure of 0.4 MPa/ cm2 to crush wrinkles from above and below.
  • This paper container was designated Example 4.
  • the first to third resin layers were formed on the paperboard base paper by preparing in advance a composite film (gas barrier resin film) in which the second and third resin layers were laminated together, and then laminating this gas barrier resin film on top of the first resin layer when extrusion laminating polypropylene resin onto the surface of the paperboard base paper as the first resin layer.
  • a composite film gas barrier resin film
  • Example 5 instead of the paperboard base paper used in Example 1, a paperboard base paper having a thickness of about 0.3 mm and a basis weight of about 260 g/ m2 was used, in which a polypropylene resin of about 20 ⁇ m was extrusion laminated on one side of the paperboard base paper and a polypropylene resin of about 20 ⁇ m was laminated on the other side, in order from the surface of the paperboard base paper, as a first resin layer, a polypropylene resin of about 20 ⁇ m, an ethylene-vinyl alcohol copolymer resin of about 20 ⁇ m, and a polypropylene resin of about 20 ⁇ m was laminated on the other side.
  • a paper container was press-molded in the same manner as in Example 1 so that the side of the paperboard base paper on which only the polypropylene resin was formed was the inner surface side of the container, and ultrasonic vibrations of 3.0 kW were applied to the flange part for 1.5 seconds using the same ultrasonic processing device as in Example 1, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles from above and below.
  • This paper container was named Example 5.
  • the formation of the first to third resin layers on the paperboard base paper was performed in the same manner as in Example 4.
  • Example 6 A paper container was press-molded in the same manner as in Example 1, except that the formation of the creases in the paperboard base paper in the preparation step of Example 1 was carried out in a manner described below, and ultrasonic vibrations of 3.0 kW were applied to the flange portion for 1.0 second using the same ultrasonic processing device as in Example 1, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles from above and below.
  • This paper container was designated Example 6.
  • the creases in the paperboard base paper were formed so that the creases in the portion corresponding to the side wall portion of the paper container after press molding were folded from the inner surface side of the container to the outer surface side of the container, and the creases in the portion corresponding to the flange portion of the paper container after press molding were formed so that they were folded from the outer surface side of the container to the inner surface side of the container, and there was a portion between the creases corresponding to the creases in the side wall portion and the creases corresponding to the creases in the flange portion where the creases were not connected.
  • the paper container after the pressing process but before the wrinkle pressing process using the ultrasonic processing device has wrinkles formed in its side wall as if it were folded from the inner surface of the container to the outer surface of the container (hereinafter, the state in which wrinkles are formed as if it is folded from the inner surface of the container to the outer surface of the container is referred to as ⁇ with the grain''), and the flange portion has wrinkles formed against the grain, and the wrinkles in the flange portion are crushed by the wrinkle pressing process using the ultrasonic processing device.
  • Example 7 A paper container was press-molded in the same manner as in Example 6, and ultrasonic vibrations of 3.0 kW were applied to the flange portion for 1.5 seconds using the same ultrasonic processing device as in Example 6, applying a pressure of 0.4 MPa/ cm2 to crush wrinkles from above and below.
  • This paper container was designated Example 7.
  • Comparative Example 1 A paper container press-formed in the same manner as in Example 1 was used as Comparative Example 1. That is, this is a paper container that was not subjected to a wrinkle pressing step using an ultrasonic processing device.
  • Comparative Example 2 A paper container was press-formed in the same manner as in Example 1, but the flange portion was not subjected to a wrinkle pressing process using an ultrasonic processing device, and instead, a pressure of 0.4 MPa/ cm2 was applied to the flange portion to crush the wrinkles.
  • This paper container was designated as Comparative Example 2. In other words, it is a paper container that was not subjected to a wrinkle pressing process using an ultrasonic processing device.
  • Comparative Example 3 A paper container was formed by press-molding a paperboard base paper on which resin layers were formed on both sides and on which creases were formed in the side wall portion corresponding portion, the flange portion corresponding portion, and the rolled edge portion corresponding portion.
  • the paperboard base paper had a paperboard thickness of about 0.3 mm and a basis weight of about 260 g/ m2 , and was extrusion-laminated with about 20 ⁇ m of polypropylene resin on each side.
  • the size of the paper container was about 179 mm in the long side direction (including the flange portion) in plan view, about 120 mm in the short side direction (including the flange portion), about 30 mm in height from the bottom to the flange portion, and about 3 mm in diameter of the rolled edge portion.
  • This paper container was designated as Comparative Example 3. That is, it is a paper container in which the wrinkles are formed in a different direction from Example 1, and is a paper container that has not been subjected to a wrinkle pressing process using an ultrasonic processing device.
  • Comparative Example 4 A paper container press-formed in the same manner as in Comparative Example 3 was subjected to ultrasonic vibrations of 3.0 kW for 1.0 second to the flange portion using the same ultrasonic processing device as in Example 1, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles.
  • This paper container was designated Comparative Example 4. That is, this is a paper container in which the wrinkles are formed in a different direction from that in Example 1, and which underwent a wrinkle pressing process using the ultrasonic processing device under the same conditions as in Example 2.
  • Comparative Example 5 A paper container press-formed in the same manner as in Comparative Example 3 was subjected to ultrasonic vibrations of 3.0 kW for 1.5 seconds on the flange portion using the same ultrasonic processing device as in Example 1, and a pressure of 0.4 MPa/ cm2 was applied to crush wrinkles.
  • This paper container was designated Comparative Example 5. That is, this is a paper container in which the wrinkles are formed in a different direction from that in Example 1, and which underwent a wrinkle pressing process using the ultrasonic processing device under the same conditions as in Example 3.
  • Comparative Example 6 A paper container press-formed in the same manner as in Example 4 was used as Comparative Example 6. That is, this is a paper container that was not subjected to a wrinkle pressing step using an ultrasonic processing device.
  • Test 1-1 Measurement test of thickness of cross section of wrinkled paper container The cross section thickness of the wrinkled paper container was measured at four points of the flange part using a micrometer.
  • the micrometer used was manufactured by Mitutoyo Corporation, product number: M110-25.
  • the measurement points were two points on either side of the flange in the longitudinal direction (measurement points A and C) and two points on either side of the flange in the lateral direction (measurement points B and D).
  • the cross-sectional thickness of the paper container with wrinkles before and after ultrasonic processing of the flange portion was calculated. Note that in this test, since ultrasonic processing was not performed on the side wall portion, the cross-sectional thickness of the paper container with wrinkles in the side wall portion was used as the cross-sectional thickness of the paper container with wrinkles in the flange portion before ultrasonic processing.
  • Example 2 the four-point average of Examples 1 to 7, which were subjected to ultrasonic processing, was S1/S2 ⁇ 0.7.
  • Test 1-2 Air leakage test A sample for the thickness measurement test of the cross section of a wrinkled paper container was top-sealed, 0.1 MPa compressed air was enclosed, and the sample was submerged in water, and air leakage from the sealed surface was visually confirmed. The sealing conditions were a heating temperature of 180 degrees, a heating time of 2 seconds, a pressure of 0.5 MPa/ cm2 , and one sealing.
  • Example 2 In which S1/S2 was less than 0.7, there was no air leakage and the top sealability was further improved.
  • Test 1-3 Oxygen gas permeability measurement test 1. Preparation of measurement samples As measurement samples, the paper containers of Examples 4 and 5 were prepared. In addition, as Example 5-2, a paper container was prepared in the same manner as in Example 5, except that in the paper container of Example 5, the second resin layer was an ethylene-vinyl alcohol copolymer resin with a thickness of about 10 ⁇ m. All of the paper containers were subjected to a wrinkle pressing process.
  • a laminate film manufactured by Mitsubishi Chemical Corporation, product name Diamiron VM60 having a total thickness of 50 ⁇ m and comprising an EVOH (ethylene vinyl alcohol copolymer resin)/nylon/PP (polypropylene resin) easy peel sealant layer structure was dry laminated with a 12 ⁇ m PET (polyethylene terephthalate resin) film to produce a lid material with top sealing properties and a PET/EVOH/nylon/easy peel sealant layer structure.
  • This lid material was top sealed to the flange portion of the paper container of Examples 4, 5, and 5-2 with the easy peel sealant layer facing the paper container, thereby preparing a top-sealed paper container of the present invention.
  • the oxygen gas permeabilities of the top-sealed paper containers of Examples 4, 5, and 5-2 obtained in 1 above were measured by a method in accordance with JIS K7126-2.
  • the measuring device and measuring conditions were as follows, and the top-sealed paper container itself was used as the measurement sample.
  • Measuring device OX-TRAN2/21 (manufactured by MOCON) Temperature and humidity: 23°C 50% RH air (outside test gas), 23°C dry nitrogen (inside carrier gas) Permeation gas: air (21% oxygen) Permeation direction: from outside to inside. The permeation results are shown in Table 4 below.
  • the measurement equipment used was the "Autograph” (registered trademark) material testing machine manufactured by Shimadzu Corporation, and its data processing software “TRAPEZIUM” (registered trademark).
  • FIG. 6 is a schematic diagram showing a measurement test performed on the paper container shown in Figure 1.
  • the paper container 1 was pressed from the direction indicated by the arrow in the figure while the bottom end was fixed by the measuring device 30, and the stress was measured by the measuring device 30.
  • the measurement test was carried out on three pieces each of the Example and Comparative Example, and the arithmetic average of the three measurements was calculated to obtain the measurement test results.
  • Figure 7 is a graph showing the results of the measurement test shown in Figure 6, where (1) is the longitudinal direction and (2) is the transverse direction.
  • Example 7(1) when the same test force [N] was applied in the longitudinal direction to the paper containers of the Example and Comparative Example, it was found that the Example had a smaller deformation amount [mm] than the Comparative Example. Also, it was found that, among Examples 1 to 3, Example 3, which had the longest ultrasonic processing time, had the smallest deformation amount [mm].
  • III. Measurement Test in the Short Side Direction The measurement method was the same as that of the measurement test in the long side direction, except that the paper container was tilted by 90 degrees.
  • Example 3 which had the longest ultrasonic processing time, showed the largest decrease in the amount of deformation [mm].
  • the paper container, top-sealed paper container, and paper container manufacturing method of the present invention are suitable for storing, for example, food, etc.

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Containers Having Bodies Formed In One Piece (AREA)

Abstract

Un réceptacle en papier est principalement composé de la partie inférieure, d'une partie paroi latérale qui est reliée à la partie inférieure, d'une partie rebord qui est reliée à l'extrémité supérieure de la partie paroi latérale et qui s'étend horizontalement vers l'extérieur, et d'une partie enroulée de bord qui est reliée au bord périphérique externe de la partie rebord. La partie rebord présente une pluralité de plis (6) (comprenant des plis de broyage (7)) qui sont chacun formés, par moulage à la presse, pour être pliés de la surface inférieure à la surface supérieure. En outre, chacun des plis (6) (comprenant les plis de broyage (7)) de la partie rebord est au moins partiellement formé avec une partie plate (28). Au moyen d'une telle configuration, la partie rebord est aplatie et la présence ou l'absence d'un espace fin (25) à l'intérieur du pli (6) n'affecte pas le étanchéité supérieure et, par conséquent, un réceptacle en papier qui présente des propriétés d'étanchéité supérieures améliorées lors de la réalisation d'une étanchéité supérieure à l'aide d'un matériau de couvercle tel qu'un film d'étanchéité supérieur est obtenu. Par ailleurs, la résistance est améliorée en comparaison avec un réceptacle en papier classique dans lequel les plis ne sont pas aplatis.
PCT/JP2023/047012 2022-07-27 2023-12-27 Réceptacle en papier, réceptacle en papier à étanchéité supérieure et procédé de fabrication de réceptacle en papier Pending WO2025022687A1 (fr)

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JP2023121680A JP2024019096A (ja) 2022-07-27 2023-07-26 紙容器、トップシール紙容器及び紙容器の製造方法
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0940035A (ja) * 1995-07-24 1997-02-10 House Foods Corp 紙製調理容器
JPH10244610A (ja) * 1997-03-06 1998-09-14 Idemitsu Petrochem Co Ltd 多層シート及び容器
JP2000033927A (ja) * 1998-07-16 2000-02-02 Dainippon Printing Co Ltd 深絞り紙トレーの製造方法
JP2008087819A (ja) * 2006-10-02 2008-04-17 Dainippon Printing Co Ltd 絞り成形紙製容器およびその製造方法
EP2193997A1 (fr) * 2008-03-20 2010-06-09 Huhtamäki Oyj Plateau par étirage profond

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0940035A (ja) * 1995-07-24 1997-02-10 House Foods Corp 紙製調理容器
JPH10244610A (ja) * 1997-03-06 1998-09-14 Idemitsu Petrochem Co Ltd 多層シート及び容器
JP2000033927A (ja) * 1998-07-16 2000-02-02 Dainippon Printing Co Ltd 深絞り紙トレーの製造方法
JP2008087819A (ja) * 2006-10-02 2008-04-17 Dainippon Printing Co Ltd 絞り成形紙製容器およびその製造方法
EP2193997A1 (fr) * 2008-03-20 2010-06-09 Huhtamäki Oyj Plateau par étirage profond

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