JP4716439B2 - Method for manufacturing food storage container - Google Patents

Description

The present invention relates to a method for manufacturing a food storage container formed of pulp material, and more particularly to a method for industrially manufacturing a food storage container that can be folded back to form a beautiful bowl-shaped portion .

  Conventionally, plastic materials such as polyurethane foam have been used as food storage containers such as lunch boxes or trays for storing food. However, since plastic materials are not easily post-processed after use, there is a strong demand for food storage containers made of vegetable fiber materials from the viewpoint of environmental protection.

  Because the container from the cardboard of the pulp is manufactured by forming incisions at the four corners, raising the side pieces, overlapping the ends of the side pieces at the corners and gluing them together, and attaching them manually However, there was a drawback that the cost was extremely high. For this reason, it is hardly spread as a food storage container such as an inexpensive tray sold in a supermarket or the like.

  Further, a paper container in which a large number of ridges are formed in a bellows shape at a corner portion and a film is coated on the surface has been known. However, since the bellows easily opens, there is a problem that strength is weak.

  In order to solve such a problem, the present applicant has a process of forming a cardboard from a pulp material (pulp or a vegetable fiber material containing pulp as a main component) as shown in FIG. A step of coating a thermoplastic resin having, a step of forming cut portions for forming side pieces at the four corners of the cardboard, and the cardboard obtained in this way is heated and pressed with a pair of concave and convex press dies. A food storage container 2 having side overlapping pieces 1 at the four corners was developed and a patent application was filed first (Patent Document 1).

  The container made of this pulp material has received extremely high evaluation from the viewpoints of being able to be formed at low cost and environmental protection. However, in this case, even if the inner surface of the container is coated with a thermoplastic resin, when meat, fish, levers, etc. are inserted, blood from meat or the like from the end portion (material cut surface) 3 of the overlapping portion 1 of the side piece There was a problem that it penetrated so that the appearance of the container became dirty. Needless to say, no problem arises when the contents do not produce liquid juice such as blood.

  Further, as shown in FIG. 2, the present applicant has a step of forming a cardboard from a pulp material, a step of coating a thermoplastic resin having a heat sealing ability, and a side piece adjacent to the four corners of the cardboard. Forming the folded piece 4 that connects the two, and the folded piece 4 is superposed and adhered to the side piece 5 in a state in which the cardboard obtained in this way is heated and pressed with a pair of concave and convex press dies. Developed a food storage container and applied for a patent earlier (Patent Document 2).

However, a container formed from a pulp material having such a conventional folded piece has a problem that when folded, a lot of wrinkles may be generated or torn, and a beautiful wrinkle- like portion cannot be formed.
JP 2006-315687 A JP2007-1621

This invention is made in view of such a point, and it aims at providing the food storage container which can form a beautiful bowl-shaped part without generating many cracks even if it folds back and tearing .

The configuration of the present invention that meets the above-described object is a cutting method in which a pulp material is formed into a cardboard material, and the cardboard material is coated with a thermoplastic resin having a heat sealing ability, and side pieces are formed at the four corners of the cardboard material. A folded piece connecting the side pieces adjacent to the four corners, the folded piece being formed shorter than both adjacent side parts, and one opposing side piece of the cardboard-like material is opposed to the other Stand up before the side piece, heat-press with a concavo-convex mold, the folded piece overlaps with the side piece, forming the overlapping part of the side piece at the four corners, the part above the folded piece of the overlapping part folding Kaee to have been formed by the arc forming the flange portion, and having a cutting surface of the pulp material to an end of the overlapping portion of the inner surface of the container.

The folded piece is in contact with the lower end of the cut portion and folds back the double portion above the folded piece of the overlapping portion (Claim 2). The folding piece is folded piece of both sides are V-shaped (hereinafter, simply referred to as folded piece of V-shaped) is preferably (claim 3). The thermoplastic resin having a heat sealing ability is preferably a polyethylene or polypropylene (claim 4). The hook-shaped portion is preferably formed in a U-shaped cross section (Claim 5) . It said container, after accommodating the contents to the container, preferably by wrapping the film is a tray consisting configured to cover the flange-like portion upper surface and opening (Claim 6). Preferably, the pulp material is pulp alone or a mixture of pulp and other vegetable fiber materials (Claim 7).

As described above, according to the present invention, there is a great effect that a beautiful bowl-shaped portion 12 can be formed by forming the overlapping portion of the side piece and folding back the portion above the folded piece.

Next, an embodiment of the present invention will be described.

The present invention forms a food container from a pulp material.
In order to form a food container from pulp or pulp-based material, it is formed from pulp or pulp-based material into a cardboard material of a predetermined size and has a heat seal ability on the back What is necessary is just to heat-press the cardboard material which apply | coated resin and formed the cutting part which forms a side piece in the four corners of the said cardboard material with a pair of uneven | corrugated press molds. In order to press with a press die, the opposing side piece must be raised first.

FIG. 5 shows an example of a mold used for this purpose, and rods 10 and 10 ′ are fixed to one opposing portion of the periphery of the mold recess 11. The side piece to be raised first may be placed on the rod 10, 10 '.

  In order to produce a cardboard from a pulp material, a known method may be used. In other words, what is obtained by suspending the pulp material in water may be made into a cardboard material through a plowing process, a chopping process, and a drying process. The cardboard material obtained in this way is cut into the developed shape of the container or lid to be formed. In addition, it is good for a cardboard to contain a water-proofing agent. In addition, the pulp manufactured from used paper like old newspaper can also be used instead of virgin pulp.

  As the vegetable fiber material to be used with the pulp in the present invention, straw, sugar cane or kenaf can be used, but the virgin pulp alone or pulp from waste paper alone is used from the viewpoint of strength and hygiene. The latter is preferable from the viewpoint of price.

  The step of coating the thermoplastic resin having the heat sealing ability may be before or after being cut into a developed shape. The thermoplastic resin is preferably coated on the back side of the cardboard. The reason why the thermoplastic resin is coated is that it can be formed in a container with a mold, and infiltration of moisture, blood, juice, etc. can be prevented. As the thermoplastic resin, it is particularly preferable to use polyethylene or polypropylene.

  The content of the thermoplastic resin varies depending on the type of the thermoplastic resin, but preferably the content is 3% to 6%. If it is less than this, the coating effect will not be sufficiently obtained, and if it is too much, black smoke will be emitted during incineration and clog the furnace filter. Here, the “content” is a percentage of the “mass of the applied heat sealant” with respect to the total mass of the cardboard material on which the thermoplastic resin is applied on one side.

In the cardboard-like material thus formed, cut portions for forming side pieces at the four corners are formed . Then, a crease is formed at the boundary between the bottom surface and the side surface. The crease is preferably formed by a punching die.

  In order to form a food container with a pair of concave and convex heating press molds, a cardboard-like object is placed on the concave mold shown in FIG. 5, and one opposing side piece is more than the other opposing side piece. The food storage container 2 having the bowl-shaped portion 12 having a U-shaped cross section shown in FIG. 6 is formed by standing up first and pressing and pressing it from above with a convex mold to form a container and simultaneously heat-sealing the four corners. 'Can be manufactured in one step. The saddle-shaped part 12 is formed in a U-shaped cross section because, as shown in FIG. 5, a ring-shaped ridge 13 having a square cross section is provided on the outer periphery of the concave upper end of the concave mold. In FIG. 6, 3 ′ is a cut surface located on the inner surface of the container.

  A bent portion 14 in the outer horizontal direction is continuously provided at the lower end of the bowl-shaped portion 12 having a U-shaped cross section. By providing the bent portion 14 in this manner, the portion of the laminated thermoplastic resin film that protrudes from the container can be easily cut together with the bent portion 14.

FIG. 7 shows another embodiment of the present invention, which has folding pieces 16 for connecting side pieces 5a and 5b (5b and 5c) adjacent to the four corners, and the folding pieces 16 are adjacent to both side portions. It is formed shorter.

  A crease is formed on the cardboard thus formed. The crease is preferably formed by a punching die. That is, the bent portion such as the boundary between the bottom surface and the side surface and the boundary between the side surface and the folded piece is formed with a protruding line on the punching die, and a cardboard-like material is placed on this and pressed from above, whereby the above crease is formed. Can be formed. Of course, the crease may be formed by other means.

  When the side walls 5a and 5c are erected in FIG. 7, the short V-shaped folded piece 16 is also erected together. As shown in FIG. 8, the short V-shaped folded piece 16 is formed on the surface of the side wall 5b as shown by an arrow. Adhere to. The surface of the portion longer than the short V-shaped folded piece 16 of the side wall 5b is simultaneously stuck to the back surface of the side wall 5a.

  When the side wall 5b is erected first in FIG. 7, the short V-shaped folded piece 16 also rises together. As shown in FIGS. 9 and 10, the short V-shaped folded piece 16 is formed on the side wall 5c (5a). Stick to the surface. The surface of the portion longer than the short V-shaped folded piece 16 of the side wall 5c (5a) is simultaneously adhered to the back surface of the side wall 5b.

  In the above embodiment, the thermoplastic resin is coated only on the back surface of the cardboard.

  When the portion formed above the short V-shaped piece 16 is folded back by pressing with a concavo-convex mold into the container formed with the opening formed as described above, a bowl having a U-shaped cross section as shown in FIG. The shape portion 12 can be easily formed. If the V-shaped piece 16 is lengthened and folded back together with the V-shaped folded piece 16, a lot of wrinkles may be generated or torn, and a beautiful wrinkled portion 12 cannot be formed. As shown in FIG. 5, if a mold provided with a ring-shaped ridge 13 having a square cross section on the outer periphery of the concave upper end of the concave mold is used, the four corners are heat sealed at the same time as the container is formed. The food storage container 2 ′ having the bowl-shaped part 12 having a U-shaped cross section shown in FIG. The container thus obtained has a cutting part 3 ′ above the V-shaped folded piece 16.

As shown in FIG. 11, when the folded piece has a shape in which the short folded piece 16 and the side piece 16 ′ are connected to each other, the side piece 16 is attached in a state where the back surface of the short folded piece 16 is adhered to the back surface of the side piece 16 ′. The portion above the short folded piece 16 on the back surface of 'is stuck to the side wall 5b. If the length of the side piece 16 'is shorter than the side wall 5c, this container can be a container in which the cut surface of the cardboard is located at the upper end.

  In order to form a food container with a pair of concave and convex heating press molds, a cardboard is placed on the concave mold shown in FIG. 5, and one opposing side piece of the cardboard is opposed to the other. Stand up ahead of the side piece, press and heat press with a convex mold from above to form a container, and at the same time heat seal the four corners to form a food storage container.

  Although it does not specifically limit as a food storage container manufactured by the method of this invention, A tray etc. are mentioned as a suitable thing.

Since the container manufactured as described above has a cut surface of the pulp material on the inner surface of the container, blood, moisture, etc. of meat, fish, liver, etc. penetrate from here, so a plastic film is laminated as follows. Is good.
(1) As shown in FIGS. 3 and 4, air suction holes 6 (or air suction perforations 6 ′) are formed in the food container.
(2) The container 2 in which the air suction holes 6 (or the air perforation 6 ') are formed in this way is placed in a mold in which the number of fitting holes (for example, 5 to 10) is formed. The number of mating. A hot plate is disposed directly above the mold at intervals.
(3) Next, the thermoplastic resin film is pulled out between the food container and the hot plate.
(4) Then, the thermoplastic resin film is lowered and placed on the food storage container. In this state, the thermoplastic resin film sags slightly downward. When the pressure inside the mold is reduced and air is sucked and removed from the air suction hole 6 (or the perforation 6 'for air suction) of the food container, the thermoplastic resin film comes into close contact with the food container and is lowered by the hot platen. Laminated by heating. The hot plate rises to its original position.
(5) Slide the mold and cut the rear end of the film. For example, 5 to 10 laminated food containers are taken out from the mold. The mold is returned to its original position. The connected containers are cut into individual products with a film cutting machine.

  Since the food storage container of the present invention may be placed on a cutting board to store sashimi and the like, it is preferable to coat the outer peripheral surface with a synthetic resin in advance so that moisture, blood, etc. do not enter. For this purpose, the suction hole 6 and the perforation 6 'of the present invention are formed in the upper end 9 of the recessed portion 8 formed in the bottom of the food container as shown in FIG. 3, or as shown in FIG. Thus, it is formed so as to be opposed to the upper part of the side wall of the food container, or opposed to the upper part of the corner part of the food container so that water, blood, etc. on the cutting board do not touch the air suction hole. This is preferable.

  The number of air suction holes and the like formed in the recess 8 is preferably four or more at a predetermined interval so that the degree of pressure reduction between the container and the thermoplastic resin film is the same. Although the height of the concave portion depends on the size of the concave portion, the height of water accumulation is usually lower than 2 mm, so it is preferably about 2 to 4 mm.

  Further, even if the recess is not provided, an air suction hole or perforation 6 ′ may be formed on the outer peripheral surface at a position of 2 mm or more, preferably 4 mm or more from the bottom surface. Also in this case, it is preferable to provide four or more at predetermined intervals on the outer periphery (preferably at the four corners).

As shown in FIG. 4, if a container having a large number of ridges (concave / convex) 7 formed in the vicinity of the overlapping portion 1 of the side piece at the four corners, the spill 7 and the thermoplastic resin film cause an air outflow. Since the path is formed, it is not necessary to form an air suction portion (perforation 6 ′). The ridges, ridges, or concavo-convex portions are not particularly limited as long as an air outflow path reaching the upper end from the bottom surface is formed. Since the thermoplastic resin film is easily adhered uniformly, it is preferable to form the flange 7 at the upper corner portion. In particular, it is preferably formed in the vicinity of the overlapping portion 1 of the side piece and the folding piece 4 of FIG.

It is a perspective view which shows an example of a well-known food storage container. It is a perspective view which shows the other example of a well-known food storage container. It is a back surface perspective view which shows an example of the food storage container of this invention. It is a surface perspective view which shows the other example of the food storage container of this invention. It is a perspective view which shows an example of the metal mold | die which manufactures the food storage container of this invention. It is a perspective view which shows the other example of the food storage container of this invention. It is a partial expanded view which shows the other example of the food storage container of this invention. It is a fragmentary perspective view which shows the manufacturing method of the food storage container of this invention. It is a fragmentary perspective view which shows the manufacturing method of the food storage container of this invention. It is a fragmentary perspective view which shows the other example of the food storage container of this invention. It is a partially expanded view which shows the other example of the food container of this invention.

1 .... Polymerized part 2,2 '... Food collection container 3,3' ... End of side piece superposed part (cut surface)
4 .... Folding pieces 5, 5a, 5b, 5c, 5d ... Side piece (side wall)
6 ··· Air suction hole 6 '··· Air perforation 7 ······························ ... Upper end of recess
10, 10 '·························································································· Folded part 16 connected to the ring-shaped part .... Short V-shaped folded piece.

Claims (7)

Formed from a pulp material into a cardboard-like material, coated with a thermoplastic resin having a heat-sealability on the cardboard-like material, formed cut portions that form side pieces at the four corners of the cardboard-like material, and side surfaces adjacent to the four corners A folded piece connecting the pieces, the folded piece being formed shorter than both adjacent side portions, and one opposing side piece of the cardboard-like material is raised before the other opposing side piece, Heat-pressed with a mold, the folded piece overlaps the side piece, forms a superposed part of the side piece at the four corners, folds back the part above the folded piece of the superposed part, formed by the this forming method of a food container, characterized in that it comprises a cutting surface of the pulp material to an end of the overlapping portion of the inner surface of the container. The manufacturing method according to claim 1, wherein the folded piece is in contact with a lower end of the cut portion and folds back a double portion above the folded piece of the overlapping portion. The folding piece, The method according to claim 1 or 2 sides are fold piece of V-shaped. The manufacturing method according to any one of claims 1 to 3, wherein the thermoplastic resin having heat sealing ability is polyethylene or polypropylene. The manufacturing method according to claim 1, wherein the hook-shaped portion is formed in a U-shaped cross section. It said container, after accommodating the contents to the container, manufactured according to any one of claims 1 to 5 wrapping film is a tray consisting configured to cover the flange-like portion upper surface an opening Method. The manufacturing method according to any one of claims 1 to 6 , wherein the pulp material is a pulp alone or a mixture of pulp and another vegetable fiber material.

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