Method for manufacturing a paper lid for a food container and paper lid for a food container

Abstract

Disclosed is a method of manufacturing a paper lid for a food container, the method including: a blanking step of cutting out a lid forming paper having a radial fold at an edge of the lid forming paper from a raw paper having an upper surface and a lower surface, each of the upper surface and the lower surface being treated with a synthetic resin coating; a primary forming step of forming a paper lid including a lid plate and a skirt wall bent downward along an edge of the lid plate; a secondary forming step of forming a guide portion obtained by bending a large diameter portion of the skirt wall so as to be inclined outward, the guide portion guiding coupling with an upper portion of the food container; and a forming curling close contact portion configured to closely surround an outer side of a reinforcing frame of the food container by curling an upper end of the guide portion in an inward direction.

Description

Technical Field

[0001] This invention relates to a paper lid for a food container and a method for manufacturing the paper lid for a food container, and more specifically, to a paper lid for a food container and a method for manufacturing the paper lid for a food container, the paper lid being configured to increase the strength of the food container by using an environmentally friendly paper material to curl the edges of the paper lid, and being reliably applied to the food container. Background Technology

[0002] In general, food containers are used in a variety of fields. For example, they are used to hold foods such as cup noodles (ready-to-eat foods) and beverages such as water or takeaway coffee. Recently, disposable food containers made of paper materials have been used to address environmental issues.

[0003] Furthermore, considering environmental concerns, the lids for disposable paper containers are also made of paper. Korean Patent Registration No. 10-0568560 (titled "Paper Lid with Improved Compatibility") discloses a paper lid structure that is made of paper and is configured not only to maintain a stable connection with the cup container but also to improve product design.

[0004] like Figure 1 The paper lid with improved compatibility disclosed in Korean Patent Registration No. 10-0568560, as shown in the figure, has a lid body structure including a flange portion 20 that is bent downward and formed to extend vertically along the outer peripheral edge of a body portion 10 forming a circular planar shape, pleated grooves 21 formed along the flange portion 20 at predetermined intervals, and a detachable groove 11 formed along the inner corner portion where the flange portion 20 and the body portion 10 intersect. Therefore, in the process of connecting the lid body to the cup container 30, even if the diameter of the curled portion 31 of the cup container 30 is slightly different depending on the cup container 30, the size of the flange portion 20 changes according to the diameter of the curled portion 31, thereby achieving the effect of improved compatibility.

[0005] However, in the structure of the "paper lid with improved compatibility" described above, due to the change in the size of the flange 20, a disadvantage exists that the lid body may easily separate from the curled portion 31 of the cup container 30, and the contents of the cup container 30 may be poured out. In particular, since only the upper end of the curled portion 31 of the cup container 30 is accommodated in the removable groove 11 of the lid body to maintain a tight contact between them, the improvement in airtightness is limited. Furthermore, considering compatibility, since the removable groove 11 is formed along the inner corner where the flange 20 and the body portion 10 intersect, the lid body may be easily detached from the cup container 30. Summary of the Invention

[0006] Technical issues

[0007] Therefore, in view of the above problems, the present invention has been made, and the object of the present invention is to manufacture a paper lid that can cover a food container with paper having a predetermined thickness, and to provide "a paper lid for a food container and a method for manufacturing a paper lid for a food container", wherein the paper lid is configured to maintain a more stable connection between the paper lid and the curled portion (reinforcing frame) of the food container by improving the edge structure of the paper lid, and to significantly improve the strength of the food container.

[0008] Technical solution

[0009] According to aspects of the invention, the above and other objects can be achieved by providing a method for manufacturing a paper lid for a food container, the paper lid covering the upper portion of the food container, the upper portion having a reinforcing frame formed on the wall surface and curled outward to have a circular cross-sectional shape, the method comprising: a punching step of cutting a lid-forming paper having dimensions capable of forming a paper lid from a base paper having an upper surface and a lower surface, each of the upper and lower surfaces being treated with a synthetic resin coating having a thickness of 10 micrometers to 35 micrometers; and radially forming pleats on the edges of the lid-forming paper to facilitate the forming of the paper lid; a primary forming step of supplying the lid-forming paper produced in the punching step to a primary forming apparatus; and compressing the lid-forming paper while applying heat at a temperature of 100°C to 140°C to form the paper lid, the paper lid comprising a cover plate configured to cover the open upper portion of the food container while being spaced apart from the open upper portion, and a skirt wall that bends downward along the edge of the cover plate and is connected to the food container to surround the outer side of the reinforcing frame of the food container. ; and bending the skirt wall to form a small-diameter portion and a large-diameter portion, the small-diameter portion being connected to the edge of the cover plate, the small-diameter portion having a lower end that contacts the upper end of the food container, the large-diameter portion being formed to expand in diameter while forming a circular step portion configured to allow the lower end of the small-diameter portion to contact the upper end of the reinforcing frame of the food container, the large-diameter portion surrounding the outer side of the upper end of the food container while being spaced apart from the outer side of the upper end of the food container; and a secondary forming step, in which the paper cover produced in the primary forming step is moved to the secondary forming device; while applying heat to the paper cover at a temperature of 100°C to 140°C, a guide portion is formed, the guide portion being obtained by bending the large-diameter portion of the skirt wall to tilt outward in the direction toward the lower end of the large-diameter portion, the guide portion guiding the connection with the upper part of the food container; and forming a curled tight contact portion, the curled tight contact portion being configured to tightly surround the outer side of the reinforcing frame of the food container by curling the upper end of the guide portion in an inward direction to have a semi-circular cross-sectional shape while the upper end of the guide portion is connected to the circular step portion.

[0010] Furthermore, the synthetic resin coating can be made of at least one of polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET), or silicone.

[0011] In addition, the cover reinforcement can be formed in a single molding step, and the cover reinforcement is recessed downward at the center of the cover plate.

[0012] According to another aspect of the present invention, a paper lid for a food container is provided, which is manufactured by the above method, wherein the paper lid is manufactured by cutting lid forming paper from base paper and allowing the lid forming paper to undergo a primary forming step and a secondary forming step.

[0013] Beneficial effects

[0014] According to the invention, a paper lid for a food container and a method for manufacturing a paper lid for a food container, the paper lid capable of covering the food container is formed of paper having a predetermined thickness, and a skirt formed on the edge of the paper lid includes a small-diameter portion, a guide portion, and a curled tight contact portion. The small-diameter portion contacts the upper end of the food container, and the guide portion is formed by bending a large-diameter portion extending from the lower end of the small-diameter portion to be inclined outward in a direction toward its edge. The guide portion guides the connection between the paper lid and the upper part of the food container, and the curled tight contact portion is configured to tightly surround the outer side of the reinforcing frame of the food container by curling the end of the small-diameter portion and the boundary portion of the large-diameter portion in an inward direction to have a semi-circular cross-sectional shape. Therefore, the advantage is that when the upper part of the food container is covered by the paper lid, the curled tight contact portion provided in the middle of the skirt can stably cover the open upper part of the food container by completely surrounding the outer side of the reinforcing frame of the food container. Furthermore, the guide portion formed on the edge of the skirt and shaped to be inclined outward has the effect of allowing the paper lid to smoothly cover the food container from the upper part downward.

[0015] Furthermore, in the method for manufacturing paper lids for food containers according to the present invention, the synthetic resin coating is made of at least one of polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET), or silicone. Since the paper lid is manufactured while heat is applied to it at a temperature of 100°C to 130°C in both the primary and secondary molding steps, it is advantageous that the paper lid can be molded more easily and stably.

[0016] Furthermore, the method for manufacturing a paper lid for a food container according to the present invention increases bending strength by forming a downwardly recessed lid reinforcement in the center portion of the lid plate, thereby further improving the product reliability of the paper lid. Attached Figure Description

[0017] Figure 1 This is a view showing a paper cover with improved compatibility disclosed in Korean Patent Registration No. 100-0568560.

[0018] Figure 2 This is a perspective view showing a food container to which the present invention is applied and a paper lid for a food container according to the present invention.

[0019] Figure 3 It is along Figure 2 The cross-sectional view taken from line Ⅲ-Ⅲ in the diagram.

[0020] Figure 4 This is a process block diagram showing the method of manufacturing a paper lid for a food container according to the present invention.

[0021] Figure 5 This is a schematic view illustrating the punching step in a method of manufacturing a paper cover according to the present invention.

[0022] Figure 6 This is a schematic view illustrating a primary forming step in a method for manufacturing a paper cover according to the present invention, and a paper cover formed in that primary forming step.

[0023] Figures 7-9 This is a schematic view illustrating the secondary forming step in the method of manufacturing a paper cover according to the present invention, and the paper cover formed in the secondary forming step.

[0024] Figure 10 and Figure 11 The diagram shows a cross-sectional view of the process of covering the upper part of a food container with a paper lid according to the present invention.

[0025] List of reference numerals

[0026] 100: Food container; 110: Wall surface; 111: Reinforcing frame

[0027] 120: Bottom; 200: Paper cover; 210: Cover plate

[0028] 211: Reinforcing part of the cover; 220: Skirt wall; 221: Small diameter part.

[0029] 222: Stepped section; 223: Large diameter section; 224: Guide section

[0030] 225: Tightly wound contact area; 300: Base paper; 310: Pulp

[0031] 320: Synthetic resin coating; 330: Cover forming paper; 331: Pleats

[0032] 400: Primary forming device; 500: Secondary forming device; S10: Blanking step

[0033] S20: Primary molding step; S30: Secondary molding step Detailed Implementation

[0034] A preferred embodiment of the invention will be described in detail below with reference to the accompanying drawings.

[0035] <Description of the configuration of the paper cover according to the present invention>

[0036] First, such as Figure 2 and Figure 3 As shown, the food container 100 to which the present invention is applied is formed by a cylindrical wall surface 110 and a bottom 120 made of paper. The uppermost portion of the wall surface 110 has a reinforcing frame 111 that is rolled outward to have a circular cross-sectional shape. Here, the wall surface 110 of the food container 100 has a conical tube shape formed by rolling a single layer of pulp to have a wider upper portion and a gradually narrowing lower portion, and by overlapping the opposite ends of the paper to bond them together. In this case, the upper portion has an outwardly rolled reinforcing frame 111 that is provided to increase the strength of the food container.

[0037] The paper lid 200 according to the invention, applied to the food container 100 as described above, is formed from lid-forming paper obtained by cutting raw paper to have radial pleats on its edges. The paper lid 200 includes a lid plate 210 configured to cover and spaced apart from the open upper portion of the food container 100, and a skirt 220 curved along the edge of the lid plate 210 and attached to the food container 100 to surround the exterior of a reinforcing frame 111 of the food container 100. A downwardly recessed lid reinforcement 211 is formed at the center of the lid plate 210 of the paper lid 200. Furthermore, the skirt 220 of the paper cover 200 includes: a small diameter portion 221, connected to the edge of the cover plate 210 and configured to contact the upper end of the food container 100; a guide portion 224 (large diameter portion), formed to have a step at the end of the small diameter portion 221 and configured to extend diametrically to surround and space from the uppermost part of the food container 100; and a curled tight contact portion 225, configured to tightly surround the outside of the reinforcing frame 111 of the food container 100 by curling the end of the small diameter portion 221 and the boundary portion of the guide portion 224 in an inward direction to have a circular cross-sectional shape.

[0038] In order to produce the paper lid 200 of the food container according to the present invention, lid forming paper with a disc shape and a size capable of forming the paper lid 200 is cut from the base paper, which is a single-layer pulp that is hygienic and environmentally friendly, and these sheets of lid forming paper are continuously supplied from the lid forming device to produce the paper lid 200.

[0039] <Description of a method for manufacturing a paper cap for a disposable container according to the present invention>

[0040] Next, we will see Figures 4-9A method for manufacturing a paper cover configured as described above according to the present invention is described.

[0041] like Figure 4 The method for manufacturing a paper lid for a food container according to the present invention, as shown in the figure, includes: a punching step (S10) of cutting a lid-forming paper having a disc shape and dimensions capable of forming a paper lid 200 from a base paper; a primary forming step (S20) of forming a paper lid 200 including a lid plate 210 and a skirt 220 using the lid-forming paper produced in the punching step (S10); and a secondary forming step (S30) of forming a curled tight contact portion 225 so that the skirt 220 of the paper lid 200 produced in the primary forming step (S20) has a circular cross-sectional shape in the middle, and simultaneously forming a guide portion 224.

[0042] See Figure 5 The die-cutting step (S10) is a process of cutting a cover-forming paper 330 from the base paper 300, which has a disc shape and dimensions capable of forming the paper cover 200. The base paper 300 uses a single layer of pulp 310 having an upper surface and a lower surface, each of which is treated with a synthetic resin coating 320 to prevent moisture penetration into the base paper 300. The cover-forming paper 330, having a disc shape and dimensions capable of forming the paper cover 200, is cut from the base paper 300 using a wooden die (referred to as the "Thomson process"). In this process, preferably, pleats 331 are formed radially on the edges of the cover-forming paper 330 to facilitate cover forming. That is, when radial pressure is applied to the edges of the cover-forming paper 330 to form pleats 331, the cover-forming paper 330 deforms along the pleats 331, thereby easily forming the paper cover 200. In embodiments of the present invention, the base paper 300, which serves as the raw material for the cover forming paper 330, is a single-layer pulp 310, and each of the upper and lower surfaces of the pulp 310 is preferably treated with a synthetic resin coating 320 having a thickness of about 10 micrometers (μm) to 35 micrometers (μm). Furthermore, the synthetic resin coating 320 treated on the base paper 300 preferably uses an environmentally friendly synthetic resin material that is not absorbed into the body and is harmless to health. For example, at least one of polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET), or silicone can be used as the synthetic resin coating 320. This synthetic resin coating 320 not only prevents moisture penetration into the pulp 310 but also promotes the formation of the paper cover 200.

[0043] like Figure 6As shown, the one-step forming step (S20) is a process in which the lid forming paper 330 produced in the punching step (S10) is supplied to the one-step forming apparatus 400 and heat is applied to the forming paper 330 to form the paper lid 200. The paper lid 200 includes a cover plate 210 configured to cover the open upper portion of a food container 100 and spaced apart from the open upper portion, and a skirt wall 220 that is bent along the edge of the cover plate 210 and connected to the food container 100 to surround the outer side of the reinforcing frame 111 of the food container 100. The cover plate 210 includes a lid reinforcement 211 corresponding to the central portion of the lid forming paper 330. The lid reinforcement 221 is formed at the central portion of the cover plate 210 and is recessed downward. The cross-section of the cover plate 210 is changed by the lid reinforcement 211 to increase the bending strength (also known as flexural strength), thereby producing a more durable paper lid 200. Furthermore, in the one-step forming step (S20), the skirt 220 is bent to form a small-diameter portion 221 and a large-diameter portion 223. The small-diameter portion 221 is connected to the edge of the cover plate 210 and has a lower end that contacts the upper end of the food container 100. The large-diameter portion 223 is formed to expand in diameter while forming a circular step portion 222 to allow the lower end (end) of the small-diameter portion 221 to contact the upper end of the reinforcing frame 111 of the food container 100. The large-diameter portion 223 surrounds the outer edge of the uppermost end of the food container 100 and is spaced apart from it. As described above, in the die-cutting step (S10), pleats 331 are formed radially on the edge of the cover forming paper 330, thereby making it easy to form the skirt 220 including the small-diameter portion 221 and the large-diameter portion 223 in the one-step forming step (S20).

[0044] like Figures 7-9 As shown, the secondary forming step (S30) is a process in which the paper cover 200, formed in the primary forming step (S20), is moved to the secondary forming apparatus 500. A guide portion 224 is formed by bending the large-diameter portion 223 of the skirt wall 220 to apply heat to the paper cover 200 while tilting it outwards toward the lower end (end) of the large-diameter portion 223. A rolled-up close contact portion 225, configured to tightly surround the exterior of the reinforcing frame 111 of the food container 100, is formed by curling the upper end of the guide portion 224 inwards to have a semi-circular cross-sectional shape, while the upper end of the guide portion 224 is connected to the circular step portion 222. The guide portion 224 is provided to facilitate connection with the upper part of the food container 100, and preferably the guide portion 224 and the rolled-up close contact portion 225 are formed simultaneously.

[0045] Meanwhile, in embodiments of the present invention, in the primary molding step (S20) and the secondary molding step (S30), each molding device (mold 400 and 500) is preheated to a temperature of 100°C to 140°C (120°C in this embodiment) by a heater. Under this heating state, it is preferable to apply heat to the cover molding paper 330 and the one-time paper cover 200 while compressing them, so as to plastically deform the synthetic resin coating 320. In this short-time heating and compression process, the synthetic resin coating 320 treated on each of the upper and lower surfaces of the cover molding paper 330 is not damaged by heat, and when the molding of the paper cover 200 is completed, the synthetic resin coating 320 hardens again and remains in the molded state (plastic deformation state). In other words, when the paper cover 200 is formed and the synthetic resin coating 320 is cooled, the forming state of the cover plate 210, the small diameter portion 221, the guide portion 224 and the curled tight contact portion 225 remains unchanged.

[0046] More specifically, such as Figure 9 As shown, in the paper cover 200 manufactured by the method according to the invention, the skirt 220 includes a small diameter portion 221, a guide portion 224, and a curled tight contact portion 225. The small diameter portion 221 is configured to space the cover plate 210 and the open upper portion of the food container 100 apart from each other. The guide portion 224 is configured to expand in diameter while forming a circular step portion 222 so as to allow the lower end of the small diameter portion 221 to contact the upper end of the reinforcing frame 111 of the food container 100. The guide portion 224 is bent to be inclined outward in the direction toward its end so as to guide the connection between the paper cover 200 and the upper portion of the food container 100. The curled tight contact portion 225 is configured to tightly surround the outside of the reinforcing frame 111 of the food container 100 by curling the upper end of the guide portion 224 in an inward direction to have a semi-circular cross-sectional shape while the upper end of the guide portion 224 is connected to the step portion 222.

[0047] Therefore, as Figure 10 and Figure 11 As shown in the figure, when the paper cover 200 is pressed from the top (see Figure 200) Figure 10(As indicated by the arrow in the image) When the paper lid 200 is used to cover the food container 100, the curled, tight-fitting portion 225 provided in the middle of the skirt wall 220 can stably cover the open upper portion of the food container 100 by tightly surrounding the entire exterior of the reinforcing frame 111 of the food container 100. Furthermore, the guide portion 224 formed on the edge of the skirt wall 220 and shaped to be outwardly inclined has the function of allowing the paper lid 200 to smoothly cover the food container 100 downwards from the upper portion. According to this configuration, the paper lid 200 can also be used in automated production lines to cover the food container 100 by easily pressing it downwards from the upper portion.

[0048] Furthermore, since the paper cover 200 of the food container 100 according to the present invention is manufactured by applying heat to the paper cover 200 at a temperature of 100°C to 130°C in the primary molding step (S20) and the secondary molding step (S30), the layer plastic deformation of the synthetic resin coating 320 is easier and more stable to form.

[0049] Furthermore, in the paperboard 200 for food container 100 according to the present invention, bending strength is increased by forming a downwardly recessed lid reinforcement 211 at the center portion of the lid 210, thereby further improving the product reliability of the paper lid 200.

[0050] Industrial applicability

[0051] This invention can be widely used in the field of "paper lids for food containers and methods of manufacturing paper lids for food containers", wherein the paper lid is configured to increase the strength of the food container by using environmentally friendly paper material to curl the edges of the paper lid, and is reliably applied to food containers.

Claims

1. A method of manufacturing a paper lid (200) for a food container (100), the paper lid (200) covering an upper portion of the food container (100), the upper portion having an uppermost portion formed on a wall surface (110) and outwardly rolled to have a circular cross-sectional shape, the method comprising: In the die-cutting step (S10), a cover-forming paper (330) with a size capable of forming the paper cover (200) is cut from the base paper (300) having an upper surface and a lower surface, each of the upper surface and the lower surface being treated with a synthetic resin coating (320) with a thickness of 10 micrometers to 35 micrometers. And radial pleats (331) are formed on the edge of the cover forming paper (330) to facilitate the forming of the paper cover (200); In the one-step forming step (S20), the lid forming paper (330) produced in the punching step (S10) is supplied to the one-step forming device (400); the lid forming paper (330) is compressed while being heated at a temperature of 100°C to 140°C to form the paper lid (200), the paper lid (200) including a cover plate (210) configured to cover the open upper portion of the food container (100) and spaced apart from the open upper portion, and a skirt wall (220) that bends downward along the edge of the cover plate (210) and is connected to the food container (100) to surround the outside of the reinforcing frame (111) of the food container (100); The skirt wall (220) is bent to form a small-diameter portion (221) and a large-diameter portion (223), the small-diameter portion (221) being connected to the edge of the cover plate (210), the small-diameter portion (221) having a lower end contacting the upper end of the food container (100), the large-diameter portion (223) being formed to expand diametrically while forming a circular step portion (222) configured to allow the lower end of the small-diameter portion (221) to contact the upper end of the reinforcing frame (111) of the food container (100), the large-diameter portion (223) surrounding the outer side of the upper end of the food container (100) while being spaced apart from the outer side of the upper end of the food container (100); and In the secondary forming step (S30), the paper cover (200) formed in the primary forming step (S20) is moved to the secondary forming device (500); while applying heat to the paper cover (200) at a temperature of 100°C to 140°C, a guide portion (224) is formed, which is obtained by bending the large diameter portion (223) of the skirt wall (220) to be inclined outward in the direction toward the lower end of the large diameter portion (223), and the guide portion (224) guides the connection with the upper part of the food container (100); and a curled tight contact portion (225) is formed, which is configured to tightly surround the outside of the reinforcing frame (111) of the food container (100) by curling the upper end of the guide portion (224) in the inward direction to have a semi-circular cross-sectional shape, while the upper end of the guide portion (224) is connected to the circular step portion (222).

2. The method according to claim 1, wherein the synthetic resin coating (320) is made of at least one of polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET), or silicone.

3. The method according to claim 1, wherein the cover reinforcement (211) is formed in the one-time forming step (S20), and the cover reinforcement (211) is recessed downward at the center portion of the cover plate (210).

4. A paper lid for a food container manufactured by the method of any one of claims 1 and 2.

Images