JP4766593B2 - Method for manufacturing food storage container - Google Patents

Description

The present invention relates to a method for manufacturing a food storage container formed from a vegetable fiber material. More specifically, the present invention relates to a method for industrially manufacturing a food storage container formed from a vegetable fiber material.

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.

However, when a food container made of vegetable fiber material is manufactured by molding, only a shallow and weak food container can be manufactured. Also, containers made from pulp cardboard are manufactured by a method of forming cuts at the four corners, raising the side pieces, overlapping the sides of the side pieces at the corners, and gluing them together. Therefore, there was a drawback that the cost was extremely high. For this reason, food storage containers made of vegetable fiber materials are hardly spread as food storage containers such as inexpensive trays sold at supermarkets and the like.

On the other hand, paper as a vegetable fiber material is cut from natural forests, including virgin forests, for the raw materials of paper, but cutting of primary forests and natural forests is not limited to natural ecosystems where various animals live. It is regarded as a problem because it destroys the local environment.

Among these inventions, the invention described in claim 1 provides a method for producing a vegetable fiber material food storage container using a mold that has practical strength and can be produced industrially at low cost. It shall be the purpose.

The configuration of the present invention that meets the above-described object is a process of forming a cardboard material having a predetermined size from one or more plant fiber materials, and a thermoplastic resin having a heat sealing ability on the cardboard material. A step of coating, a step of forming cut portions for forming side pieces at the four corners of the cardboard-like material, and a cardboard-like material obtained in this way is heated and pressed with a pair of concave and convex press dies to form a food container And the one opposing side piece is placed on the concave mold so as to stand before the other opposing side piece, and is pressed by the convex mold in this state. Heat-pressed , the side pieces are adhered to each other, the corners of the four corners are formed to be rounded, and a food storage container in which a bowl-shaped portion is continuously formed at the upper edge is characterized by you.

  It is particularly preferable that the thermoplastic resin having the heat sealing ability is coated on one side (one of the front and back sides) of the cardboard because it can be replaced with plastic in terms of cost and printing is possible. ). In fact, if both sides are coated, the current technology is expensive and cannot be replaced by plastic.

  The cutting portion is preferably formed so that the tip corner or cutting line reaches the corner of the bottom surface of the container to be formed (Claim 3), and it is further formed into a V shape with an angle of 20 ° to 60 °. Preferred (claim 4).

Forming the cut portion in a funnel shape or a substantially Y shape is particularly preferable since water leakage from the corner inner surface can be effectively prevented (Claim 5). Especially when accommodating those troubled by water leakage is not that good to such.

A convex portion is formed at one opposing portion of the concave periphery of the concave mold, and the side piece on one opposing convex portion of the cardboard-like material is ahead of the other opposing side piece. Thus, the food storage container in which the four corners are bonded together by a heat press using a mold can be manufactured industrially at a low cost (Claim 6).

The pulp and one or more vegetable fiber materials other than pulp, to a mixture of a vegetable fiber materials other than pulp and pulp, not preferable from the standpoint of preventing destruction of the global environment by deforestation .

Plant fiber material other than the pulp, reed, not the preferred in the range of sugarcane or kenaf.

The ratio of the pulp and the vegetable fiber material other than pulp is preferably 20 to 80% by weight of the vegetable fiber material other than pulp. If this amount is not added, the effect of protecting the global environment is poor, and if it is more than this, the strength is weakened and the bonded part is easily peeled off.

The thermoplastic resin having heat sealing ability used in the present invention is preferably polyethylene or polypropylene (Claim 7 ).

According to the onset bright, food container having a practical strength consisting of vegetable fiber material, because it can be industrially produced at low cost, because can sufficiently substitute for plastic food container, contributing to environmental protection It is extremely large.

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

The present invention comprises the following steps.
(1) It is formed into a cardboard material of a predetermined size from one or more of pulp and vegetable fiber materials other than pulp.
(2) A thermoplastic resin having a heat sealing ability is applied.
(3) Form cutting parts for forming side pieces at the four corners of the cardboard.
(4) The cardboard obtained in this way is heated and pressed with a pair of concave and convex press dies to form a food container.

  The first step (1) may be performed by a known method for producing cardboard from pulp. That is, what suspended the pulp in water should just be used as a cardboard thing through a plowing process, a chopping process, and a drying process. The cardboard-like material thus obtained is cut into a square of a required size if necessary, preferably into a square with rounded corners as shown in FIGS. The cardboard material preferably contains a water resistant agent. Moreover, when accommodating the food from which oil oozes, it is preferable to contain an oil-resistant agent in addition to the water-resistant agent.

  As the vegetable fiber material other than the pulp used in the present invention, it is preferable to use straw, sugar cane or kenaf. Since the strength of the obtained food storage container is excellent, it is particularly preferable to use straw.

  In the present invention, it is preferable to use a mixture of pulp and plant fiber material other than pulp from the viewpoint of protecting the global environment by deforestation.

  The ratio of the pulp and the vegetable fiber material other than pulp is preferably 20 to 80% by weight, particularly preferably 30 to 60% by weight of the vegetable fiber material other than pulp. If this amount is not added, the effect of protecting the global environment is poor, and if it is more than this, the strength is weakened and the bonded portion is easily peeled off.

  The step of coating the thermoplastic resin having the heat sealing ability in the step (2) may be before or after forming the cut portion, but in this embodiment, before forming the cut portion. It is coated. The thermoplastic resin is preferably formed on one of the front and back sides of the cardboard. This is because, when applied to both sides, the spread of the container of the present invention is currently hindered for cost reasons, and printing cannot be performed on either side. Moreover, it is good to coat a thermoplastic resin on the surface which accommodates a foodstuff. The reason for coating the surface that contains the food is that the soaking of liquid juice 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 kind of the thermoplastic resin, but is preferably 2% to 10%, particularly preferably 3% to 6%. 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.

  The cutting part in the second step (2) may be a simple cutting line, but as shown in FIG. 1, it is preferably formed in a V shape having an angle of 90 ° or less, preferably 20 ° to 60 °.

  FIG. 1 shows an example in which the cutting part 1 of the second step (2) is formed, and the V-shaped cutting part 1 is formed on a cardboard-like material formed into a quadrangle (rectangle) with rounded corners. And the state which connected the long side piece 3, 3 'and the short side piece 4, 4' to the bottom face 2 continuously is shown. In the figure, reference numeral 5 denotes a recess formed from the bottom surface 2 to the side surface pieces 3, 3 ', 4, 4', which is formed by pressing with a mold in order to increase the strength of the tray to be manufactured. However, it is not formed in this state. In this state, it is actually as shown in FIG.

FIG. 2 shows another example in which the cut portion of the second step (2) is formed. The cut portion 1a has a V-shaped cutout portion 1 ′ continuously provided with a cutting line 6 reaching the corner of the bottom surface 2. Are formed in a substantially Y-shape (lower-case y-shape). If comprised in this way, since the overlap area of side piece 3, 3 ', 4, 4' both ends near the bottom face 2 can be enlarged, the water leak from a corner inner surface can be prevented effectively.

FIG. 3 shows another example in which the cut portion of the step (2) is formed, and a V-shaped cutout portion 1 ′ having a small angle reaching the corner of the bottom surface 2 from the upper bottom of the trapezoidal cutout portion 7. An example in which 'is continuously provided to form a funnel-shaped or substantially Y-shaped cut portion 1b is shown. If comprised in this way, since the overlap area of side piece 3, 3 ', 4, 4' both ends near the bottom face 2 can be enlarged, the water leak from a corner inner surface can be prevented effectively.

  FIG. 4 shows another example in which the cut portion of the second step (2) is formed, and the cut portion 1c reaches the corner of the bottom surface 2 at the rounded V-shaped cutout portion 1 ″. An example is shown in which 6 'is continuously provided to form a substantially Y shape (upper case Y shape). In the embodiment of FIG. 2, the cutting line 6 is a cutting line obtained by extending one of the V-shaped lines. In the embodiment of FIG. It is a cutting line that extends the line to be.

  In the embodiment of FIG. 2, the cutting line 6 may be slightly spaced, and in the embodiment of FIG. 3, the V-shaped notch 1 ′ may be a cutting line. In addition, the V shape, the Y shape, and the funnel shape may have any shape as long as it is such a shape. In short, the shape is not particularly limited as long as the tip corner or the cutting line is a notch that reaches the corner of the bottom surface 2.

  In order to form a food storage container with a pair of concave and convex heating press molds in the step (4), as shown in FIGS. Standing ahead of the opposing side piece, and placing it on the concave mold, pressing and pressing from the top with the convex mold to form a container, and at the same time heat-sealing, the four corner side pieces The containers 8 are bonded together to form a container 8 having rounded corners 13 as shown in FIG.

  Any of the opposing side pieces may be raised first, but it is preferable that the pair of short side pieces 4 and 4 ′ be raised first because they are easily raised. If the side piece is first raised by a paper folding machine, the container can be formed with a normal press mold.

  FIG. 6 shows an example of a female die (concave die) 9 used in the manufacture of the present invention, and a short side facing portion of the upper periphery of the concave portion 10 of the concave die 9 is slightly spaced from the concave portion 10. The rods 11 and 11 'having a square cross section are fixed to face each other. Guide plates 12 and 12 ′ are erected on the rods 11 and 11 ′, and a guide plate 12 ″ is erected on the rear side of the concave portion 10 of the concave mold 9.

  4, the short side piece 4, 4 'is sandwiched between the guide plates 12, 12', and one of the long side pieces 3 (or 3 ') is in contact with the guide plate 12 ". Then, it is placed on the concave portion 10 of the concave mold 9 via rods 11 and 11 '. Then, a male die (convex die) (not shown) is lowered from above, fitted into the concave portion 10 of the concave die 9, and heated and pressed.

In this way, one opposing side piece 4, 4 'comes to stand before the other opposing side piece 3, 3'. 5 can be produced in one step. In addition, as shown in FIG. 5, the bowl-shaped part 14 and the recessed part 5 of the upper end edge part of a container recessed part are formed by heat-pressing with an uneven | corrugated metal mold | die.
As shown in FIG. 6, the rods 11 and 11 'are separated from both ends of the concave portion in order to form the flange portion 14 at the upper edge. A step is formed in the recess 10, and the convex mold is formed into a shape that fits into such a recess, and a bowl-shaped portion is formed at the step where the concave mold and the convex mold are in close contact with each other. Of course, it's okay.

The container of the present invention can be provided with a lid. When the lid is continuously provided, the lid may be continuously provided on the side piece (preferably one of the side pieces 3, 3 ′) shown in FIGS.

  As shown in FIG. 5, the corner portions 13 at the four corners are thickened by thickening of the cardboard-like material, so that the portions forming the corner portions of the concave mold and / or the convex mold are cut accordingly. Good.

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

It is a top view which shows the state before the press of the food storage container of this invention. It is a top view which shows the state before the press of the other food storage container of this invention. It is a top view which shows the state before the press of the other food storage container of this invention. It is a top view which shows the state before the press of the other food storage container of this invention. It is a perspective view which shows an example of the food storage container manufactured by the method of this invention. It is a perspective view which shows an example of the concave metal mold | die used for this invention.

1, 1a, 1b, 1c ··· Cutting section 2 ··· Bottom surface 3, 3 '··· Long side piece 4, 4' ··· Short side piece 6 6 ′ ··· cutting line 8 ······································································ 12 ′, 12 ″ ···························· 13

Claims (7)

A step of forming a cardboard material having a predetermined size from one or two or more kinds of vegetable fiber materials, a step of coating the cardboard material with a thermoplastic resin having a heat sealing ability, A step of forming cut portions for forming side pieces at the four corners, and a step of heating and pressing the cardboard-like material obtained in this way with a pair of concave and convex press dies to form a food container, The opposing side pieces are placed on the concave mold so that they stand up before the other opposing side piece, and in this state, they are pressed and heated with the convex mold, and the side pieces are adhered to each other. And the corners of the four corners are formed so as to be rounded, and a food storage container having a bowl-shaped portion connected to the upper edge is formed. The manufacturing method of Claim 1 which coats the thermoplastic resin which has the said heat seal ability on the single side | surface of the said cardboard-like thing. The manufacturing method according to claim 1, wherein the cutting portion is formed such that a tip corner portion or a cutting line reaches a corner of a bottom surface of a container to be formed. The manufacturing method according to claim 3, wherein the cut portion is formed into a V shape having an angle of 20 ° to 60 °. The manufacturing method of Claim 3 which forms the said cutting part in a funnel shape or a substantially Y shape. A convex portion is formed at one opposing portion of the concave periphery of the concave mold, and the side piece on one opposing convex portion of the cardboard-like material is ahead of the other opposing side piece. The manufacturing method in any one of Claims 1-5 comprised so that it may stand up. The thermoplastic resin having a heat sealing ability, the production method according to any one of claims 1 to 6, which is a polyethylene or polypropylene.

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