JP2006016063A - Biodegradable container for instant food and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable container for an instant food having an easily peelable flange which does not injure a mouth and having biodegrading, water resisting and waterproof characteristics, and its production method. <P>SOLUTION: This biodegradable container for an instant food comprises a container body made of starch foam comprising a bottom panel part and a peripheral wall part formed on the peripheral edge of the bottom panel part and having a flange part formed on the top end of the wall part outwardly from the edge of an opening part with a predetermined distance and having a predetermined thickness and a cover part for sealing the interior of the container body by bonding the cover part on the top of the flange part. The inside face of the container body and at least the top face and the outer side face of the flange part are formed with a thermoplastic resin layer having water resisting and biodegrading characteristics. The outside face of the container body is coated with a waterproof material having biodegrading and heat fusing characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a biodegradable instant food container and a method for producing the same.

  In recent years, biodegradable materials have attracted attention as materials for various products from the viewpoint of environmental protection. Examples of such biodegradable polymers include proteins, synthetic polypeptides, aliphatic polyesters, aromatic polyesters, starches, dextran, chitosan, and the like. Among these, starches are: Since the cost is low and the production is relatively easy, it is suitable as an industrially produced material.

  On the other hand, as a container for instant foods used for foods cooked by pouring hot water (instant noodles, instant soups, instant rice cakes, etc.), currently polystyrene foam is mainly used. If it is buried in the soil as garbage after use, it remains in the soil without being permanently decomposed. For this reason, there is a concern about the environmental impact of the instant food container after use.

  From this point of view, it is considered that instant food containers are made of biodegradable materials, but when starch foam is used, it is not only biodegradable but also light and heat resistant. There is an advantage that it is difficult to convey, but there are problems with water resistance and waterproofing.If hot water is poured into an instant food container or stored for a long time, the instant food container will be deformed or dissolved by hot water or moisture. Therefore, it could not be used for instant food containers.

  Therefore, the entire surface of the starch foam container was tried to be coated with a thermoplastic resin having water resistance and biodegradability, but coating the entire container main body with a thermoplastic resin layer having water resistance and biodegradability, It was very difficult to manufacture and the cost was high.

  Therefore, it was considered that the inner surface of the starch foam container was coated with the above-mentioned thermoplastic resin layer, and the outer surface of the starch foam container was coated with a waterproof material having biodegradability such as wax. When a waterproof material is applied to the outer side surface of the flange part, if the waterproof material is also applied to the upper surface of the flange part, there will be an effect on the easy peelability and strength with the lid, while the outer side surface of the flange part. If there is a part that is not coated with waterproof material, hot water or moisture penetrates from the part, and the starch foam container is deformed, or the starch in the flange part melts and only the thermoplastic resin protrudes to cut the mouth There was a problem such as.

  In addition, starch foam containers often have problems with strength, and the adhesive state with the lid material must seal the inside sufficiently. On the other hand, when the lid is pulled at the time of opening, the flange part of the container is not destroyed. It was necessary to be able to open so that it needed a device.

  Thus, it is very difficult to process a starch foam container as an instant food container, and it has not yet been put into practical use.

  The present invention has been completed based on the inventor's original idea, and there is nothing to be described as a prior art document.

  The present invention solves such problems of the prior art, and the object of the present invention is to make use of the merit of a starch foam container that is light as a biodegradable material, difficult to transfer heat, and low in cost. On the other hand, it is necessary for an instant food container, that is, it has easy peelability with the lid, and there is no deformation of the container even if it is stored indoors for a long period of time. It is intended to provide a biodegradable instant food container excellent in water resistance, waterproofness and strength, which does not dissolve the mouth and does not damage the mouth, and a method for producing the same.

  The biodegradable instant food container of the present invention comprises a bottom plate portion and a peripheral wall portion provided at the periphery of the bottom plate portion, and a flange portion is provided at a top end of the peripheral wall portion from the opening edge to the outside. A container body made of starch foam, which is formed to have a distance and a predetermined thickness, and a lid that seals the inside of the container body by being bonded to the upper surface of the flange portion A biodegradable instant food container comprising a thermoplastic resin layer having water resistance and biodegradability formed on the inner surface of the container body and at least the upper surface and the outer side surface of the flange portion. A waterproof material having biodegradability and heat melting properties is applied to the outer surface of the container body.

  Thus, according to the biodegradable instant food container of the present invention, since it is composed of a biodegradable material, it can be decomposed by microorganisms and is environmentally friendly. In addition, a water-resistant thermoplastic resin layer is formed on the inner surface of the container main body, and the outer surface of the container main body is a container main body made of starch foam coated with a waterproof material. It can be stored for a long period of time, and the shape of the container is maintained even when hot water is added. Further, a waterproof material having heat melting property is applied to the outer surface of the container body, but since it is not applied to the upper surface of the flange portion, the easy peel property between the flange portion and the lid material is hindered. It will never be done. Furthermore, since the flange portion has a predetermined distance from the edge of the opening toward the outside, the lid member can be sufficiently bonded to the flange portion.

  In addition, since the container body is made of starch foam, it exhibits excellent heat insulation, is not hot when held in the hand, and is lightweight. Furthermore, since a waterproof material having heat melting properties is used on the outer surface of the container, it can be applied without using water or an organic solvent, and the container body can be deformed by water that has penetrated into the container body, or the container body Does not contain any organic solvent.

  In the present invention, “biodegradable” means degradable by microorganisms, and the biodegradable material includes natural resin, paper (the inner surface is coated with polyethylene or the like like a normal paper cup). In addition to substances derived from natural products such as pulp and starch, as synthetic resins, thermoplastic resins that can be used in the present invention, namely polyadipate, polylactone, polylactic acid, polyglycolic acid, polyβ-hydroxybutyric acid, aromatic Family polyester. In the present invention, these biodegradable materials may contain inorganic substances.

  “Easy peelability” refers to a property that does not peel off with a weak force such as an impact, but peels off with a strong force such as tension.

  “Heat meltability” refers to the property of being able to be handled as a liquid without being mixed with a solvent such as water or an organic solvent as long as the melting point or higher is reached. For example, those that melt at about 60 ° C. or higher, preferably about 100 ° C. or higher are preferred.

  Further, according to the present invention, in the aforementioned container, the starch foam constituting the container body is not exposed to the outside air by the water-resistant thermoplastic resin layer and the heat-meltable waterproof material. In this structure, there is no problem that the starch container gradually absorbs moisture and deforms from a portion exposed to the outside air during long-term storage. In addition, when pouring hot water and eating, starch does not touch the hot water and it does not soften or dissolve. Therefore, only the thermoplastic resin layer is exposed in the flange and the mouth is cut off. Does not occur.

  In the present invention, the thermoplastic resin layer contains at least one selected from the group consisting of polyadipate, polylactone, polylactic acid, polyglycolic acid, polyβ-hydroxybutyric acid and aromatic polyester. Is preferred. Moreover, what laminated | stacked these two or more is used preferably.

  In the present invention, it is preferable that the waterproof material is at least one selected from the group consisting of low-molecular natural resins, waxes, fatty acids, oils and fats, and derivatives thereof.

  Further, the method for producing a biodegradable instant food container of the present invention comprises a bottom plate portion and a peripheral wall portion provided on the periphery of the bottom plate portion, and a flange portion is formed on the upper end of the peripheral wall portion from the edge of the opening. A container body made of starch foam, which is formed to have a predetermined distance and a predetermined thickness, and an inner surface of the container body by being bonded to the upper surface of the flange portion. A method for producing a biodegradable instant food container comprising a lid for sealing a body, wherein a main body molding step of foaming a raw material mainly comprising starch to form a main body of the container, an inner surface of the main body of the container, and a flange A resin layer forming step for forming a water-resistant and biodegradable thermoplastic resin layer on at least the upper surface and the outer side surface of the portion, and a whole or a part of the outer side surface of the flange portion with a shielding plate having a convex portion. While covering, the container body On the surface, a coating step of coating a waterproof material having biodegradability and heat-fusible, by bonding the lid to the upper surface of the flange portion, and a sealing step of sealing the interior of the container body.

  According to the method for producing a biodegradable instant food container of the present invention, even if a waterproof material having heat melting property is formed on the outer surface of the container body by a spray method, the heat melting property is formed on the upper surface of the flange portion. Since the waterproof material having no is applied, the easy peel property between the flange portion and the lid material is not hindered. In addition, the entire container body made of starch foam is covered with a water-resistant thermoplastic resin layer and a water-resistant waterproof material, and the portion where the starch is exposed to the outside air can be eliminated. Even if stored for a period of time, there is no problem of deformation due to moisture absorption.

  The method for producing a biodegradable instant food container according to the present invention comprises a bottom plate portion and a peripheral wall portion provided at the periphery of the bottom plate portion, and a flange portion is formed on the upper end of the peripheral wall portion from the edge of the opening. A container body made of starch foam, which is formed to have a predetermined distance and a predetermined thickness, and an inner surface of the container body by being bonded to the upper surface of the flange portion. A method for producing a biodegradable instant food container comprising a lid for sealing a body, wherein a main body molding step of foaming a raw material mainly comprising starch to form a main body of the container, an inner surface of the main body of the container, and a flange A resin layer forming step for forming a water-resistant and biodegradable thermoplastic resin layer on the upper surface, outer side surface, and lower surface of the portion, and covering all or part of the lower surface of the flange portion with a shielding plate having an opening While on the outer surface of the container body A coating step of coating a waterproof material having biodegradability and heat-fusible, by bonding the lid to the upper surface of the flange portion, and a sealing step of sealing the interior of the container body.

  According to the method for producing a biodegradable instant food container of the present invention, even if a waterproof material having heat melting property is formed on the outer surface of the container body by a spray method, the heat melting property is formed on the upper surface of the flange portion. Since the waterproof material having no is applied, the easy peel property between the flange portion and the lid material is not hindered. In addition, the entire container body made of starch foam is covered with a water-resistant thermoplastic resin layer and a water-resistant waterproof material, and the portion where the starch is exposed to the outside air can be eliminated. Even if stored for a period of time, there is no problem of deformation due to moisture absorption.

  Furthermore, in the present invention, in the resin layer forming step, after molding a sheet including a thermoplastic resin layer, using the sheet, the inner surface of the container body, and at least the upper surface and the outer side surface of the flange portion, It is preferable to form a thermoplastic resin layer having biodegradability. Specifically, since the starch foam container is excellent in air permeability, the inner surface of the container main body and the flange portion are formed by a vacuum molding method with the starch foam container main body inserted into a female mold for vacuum molding. It is preferable to form a thermoplastic resin layer on the upper surface and process the outer side surface of the flange portion. In this way, the thermoplastic resin layer can be formed on the container body without damaging the container body.

  Thus, according to the biodegradable instant food container of the present invention, since it is composed of a biodegradable material, it can be decomposed by microorganisms and is environmentally friendly. Moreover, a thermoplastic resin layer resistant to hot water is formed on the inner surface of the container main body, and the outer surface of the container main body is a container main body made of starch foam coated with a waterproof material. It can be stored for a long period of time, and the shape of the container is maintained even when hot water is added, and it has sufficient water resistance, heat resistance and strength as an instant food container.

  Further, a waterproof material having heat melting property is applied to the outer surface of the container body, but since it is not applied to the upper surface of the flange portion, the easy peel property between the flange portion and the lid material is hindered. It will never be done. Furthermore, since the flange portion has a predetermined distance from the edge of the opening toward the outside, the lid member can be sufficiently bonded to the flange portion.

  In addition, since the container body is made of starch foam, it exhibits excellent heat insulation, is not hot when held in the hand, and is lightweight. Furthermore, since a waterproof material having heat melting properties is used on the outer surface of the container, it can be applied without using water or an organic solvent, and the container body can be deformed by water that has penetrated into the container body, or the container body Does not contain any organic solvent.

  Hereinafter, the present invention will be described in more detail.

  FIG. 1 is a perspective view showing an example of a biodegradable instant food container of the present invention, and FIG. 2 is a cross-sectional view (partially a side view) taken along line AA in FIG. 3 is an enlarged cross-sectional view of B of FIG.

  The biodegradable instant food container 1 includes a container body 10 and a lid 2.

  The container body 10 includes a disc-shaped bottom plate portion and a substantially cylindrical peripheral wall portion provided at the periphery of the bottom plate portion, and a circular flange portion extends outward from the edge of the opening at the upper end of the peripheral wall portion. And having a predetermined distance and a predetermined thickness.

  The predetermined distance is preferably 1.5 mm to 10 mm, and the predetermined thickness is preferably 0.5 mm to 5 mm.

  A water-resistant thermoplastic resin layer 5 is formed on the inner surface of the container body 10 and on the upper surface 10a and the outer side surface 10b of the flange portion, while on the outer surface of the container body and the lower surface 10c of the flange portion. A biodegradable and heat-meltable waterproof material layer 3 is formed. Therefore, the container body 10 does not have a portion where the starch foam is exposed.

  The lid member 2 has a disk shape, and seals the inside of the container body 10 by being bonded to the upper surface 10a of the flange portion. At this time, since the flange portion has a predetermined distance from the edge of the opening toward the outside, the lid member 2 is bonded to the flange portion with a sufficient area.

  Note that instant foods such as instant noodles, instant soups, instant bowls, etc. are enclosed in the container body 10 (not shown).

  Here, the container body 10 is made of a starch foam.

  Examples of the starch used in the container body 10 include wheat starch, potato starch, corn starch, sweet potato starch, tapioca starch, sago starch, rice starch, waxy corn starch, and high amylose-containing corn starch. Examples of the product include wheat flour, tapioca powder, corn flour, and rice flour. Moreover, you may use the modified starch which etherified or esterified these.

  Examples of the foaming agent used in the container body 10 include a compound that generates water vapor, carbon dioxide, and nitrogen when heated.

Moreover, the container main body 10 may contain, for example, an inorganic filler such as calcium carbonate, a material imparting shape retention and strength such as natural fibers, a mold release agent such as magnesium stearate, and the like.
Furthermore, it is preferable that the thickness of the container body 10 is 1 to 5 mm.

  The lid member 2 is preferably biodegradable, and examples thereof include a laminate of paper, aluminum and a biodegradable thermoplastic resin. At this time, it is preferable that the thermoplastic resin of the lid 2 and the thermoplastic resin layer 5 are thermally welded.

  The thermoplastic resin layer 5 is biodegradable and has water resistance, and is selected according to applications such as high temperature / high humidity treatment, long-term storage, oxygen gas barrier properties, and moisture resistance. Materials are used. “Water resistance” means a property that is strong against water and does not change even when contacted with water for a long time (about 1 hour). In addition, the instant food container in the present invention is also assumed to be used as a container for pouring hot water for cooking and eating, for example, and in such a case, preferably has water resistance that can withstand hot water. Appropriate.

  Therefore, it is preferable that the thermoplastic resin layer 5 contains at least one selected from the group consisting of polyadipate, polylactone, polylactic acid, polyglycolic acid, poly β-hydroxybutyric acid and aromatic polyester. It is preferable that the main component is a mixture of one or more of the above. Furthermore, the thickness of the thermoplastic resin layer 5 is preferably 5 to 100 μm.

  The thermoplastic resin layer 5 may be a laminate of the same or different resin layers. For example, polyglycolic acid has a particularly low permeability (moisture resistance) to oxygen and water vapor, but has difficulty in water resistance and the like, and therefore contains polyglycolic acid to satisfy both. You may employ | adopt this as a two-layer structure in which the layer containing polylactic acid is formed on the layer being formed.

  The waterproof material layer 3 has biodegradability and heat meltability and is excellent in waterproofness. The term “waterproof” refers to the property of being resistant to water that does not absorb water or change in quality by being in contact with water for a short time.

  The waterproof material layer 3 preferably contains at least one selected from the group consisting of low-molecular natural resins, waxes, fatty acids, oils and fats, and derivatives thereof having the above properties, and in particular. Those mainly composed of waxes are preferably used.

  Furthermore, the thickness of the waterproof material layer 3 is preferably 1 to 100 μm.

  FIG. 4 is an enlarged sectional view showing a part of another example of the biodegradable instant food container of the present invention.

  The container body 20 is formed such that a circular flange portion has a predetermined distance from the edge of the opening toward the outside and has a predetermined thickness at the upper end of the peripheral wall portion.

  In addition, a biodegradable and water-resistant thermoplastic resin layer 15 is formed on the inner surface of the container body 20 and the upper surface 20a, outer side surface 20b, and lower surface 20c of the flange portion. A biodegradable and heat-meltable waterproof material layer 13 is formed on the outer surface. Therefore, the container main body 20 does not have a portion where the starch foam is exposed.

  The lid member 12 has a disk shape, and seals the inside of the container body 20 by being bonded to the upper surface 20a of the flange portion. At this time, since the flange portion has a predetermined distance from the edge of the opening toward the outside, the lid member 12 is bonded to the flange portion with a sufficient area.

  That is, in the flange portion, the container body 10 has the thermoplastic resin layer 5 formed on the upper surface 10a and the outer side surface 10b of the flange portion, and the waterproof material layer 3 formed on the lower surface 10c of the flange portion. However, the container body 20 is different in that a thermoplastic resin layer 15 is formed on the upper surface 20a, the outer side surface 20b, and the lower surface 20c of the flange portion.

  Next, an example of a method for producing the biodegradable instant food container of the present invention will be described.

  The manufacturing method of the biodegradable instant food container 1 of the present invention includes a main body molding step, a resin layer forming step, a coating step, and a sealing step.

(1) Body molding process (see FIGS. 5, 6, 7 and 8)
The container main body 10 according to the present invention is molded by, for example, the molding device 30. The molding apparatus 30 includes a male mold 31 and a female mold 32. The female mold 32 has a plurality of substantially cylindrical recesses 33 on the upper surface and a rectangular parallelepiped that can be separated into two by dividing the recesses 33 into two. The male die 31 has a plate shape having a substantially cylindrical convex portion 34 complementary to the concave portion 33 of the female die 32 on the lower surface. The upper portion of the convex portion 34 is larger than the diameter of the concave portion 33 of the female die 32 so as to close the concave portion 33 of the female die 32, and a molding region is formed except for the upper portion of the convex portion 34. The diameter of the recess 33 of the female mold 32 is smaller. Further, a plurality of vertical ventilation grooves 35 connected to the molding region are formed on the upper portion of the convex portion 34.

  First, the raw material mixture is supplied from the nozzle 36 to the recess 33 of the female die 32 of the molding apparatus 30. When the convex portion 34 of the male die 31 is inserted into the concave portion 33 of the female die 32, a molding region is formed between the male die 31 and the female die 32, and a plurality of portions connected to the molding region are formed. The ventilation groove 35 is formed. Therefore, the convex part 34 of the male mold 31 and the concave part 33 of the female mold 32 heated to 100 to 200 ° C. expand and dry the raw material mixture, and solidify, while removing excess raw material mixture and generated steam from the molding region. The air is discharged through the ventilation groove 35.

  Next, after the male die 31 is removed, the excess raw material mixture is removed with a scraper blade or the like. And the female metal mold | die 32 is isolate | separated into two and the container main body 10 is taken out.

  Further, the container body 10 is put in an oven or the like at 60 to 200 ° C. for 1 minute to 24 hours to remove moisture from the container body 10.

  The material of the male mold 31 and the female mold 32 is preferably, for example, a metal such as iron, brass, or aluminum. Furthermore, applying the Teflon (registered trademark) coating to the male mold 31 and the female mold 32 facilitates the removal of the container body 10 and the smooth finishing of the surface of the container body 10.

  The male mold 31 and the female mold 32 can be heated by various methods. For example, an external heating element such as a gas burner, infrared light, or an electric heater element may be brought into contact with or opposed to the male mold 31 and the female mold 32. In addition, a heated liquid such as oil or a heated gas such as steam may be passed through the male mold 31 and the female mold 32 to heat the male mold 31 and the female mold 32.

  Moreover, you may heat a raw material mixture with a microwave.

  As said raw material mixture, the thing etc. which added and mixed starch, the foaming agent, and water are mentioned, for example.

  The amount of water added is preferably 35 to 60% by weight. Further, pregelatinized starch may be added in order to give the raw material mixture an appropriate viscosity. The added amount of pregelatinized starch is, for example, 0.5 to 2% by weight.

(2) Resin layer forming step (see FIGS. 9, 10 and 11)
On the other hand, a thermoplastic resin or the like is supplied to an extruder or the like equipped with a T die and melt-extruded from the T die to produce a sheet 7 having a predetermined thickness. In addition, it is preferable that predetermined thickness is 30-500 micrometers.

  Here, the thermoplastic resin layer 5 which concerns on this invention is shape | molded by the formation apparatus 40, for example. The forming apparatus 40 includes a male mold 41 and a female mold 42. The female die 42 has a rectangular parallelepiped shape having a plurality of substantially cylindrical recesses 43 on the upper surface, and is formed so that the inside of the recesses 43 can be decompressed. The male die 41 has a plate shape having a substantially cylindrical convex portion 44 complementary to the concave portion 43 of the female die 42 on the lower surface. The convex portion 44 is smaller than the diameter of the concave portion 43 of the female mold 42 so as to form a molding region.

  First, the container body 10 is placed inside the recess 43 of the female mold 42. Then, the heated sheet 7 is sent out onto the container body 10, and the inside of the recess 43 of the female mold 42 is depressurized and thermocompressed downward by the male mold 41, while the inner surface of the container body 10 and the upper surface of the flange portion A thermoplastic resin layer is formed. At this time, since the container body 10 is made of starch foam, the container body 10 is breathable, can pull the sheet 7, and is not between the thermoplastic resin layer 5 formed by adsorbing the sheet 7. Adhesive spots and air chewing do not occur. Then, considering the thickness of the flange portion, the sheet 7 is cut into a circle having a larger diameter than the outside of the flange portion, and the container body 10 having the peripheral edge portion of the sheet 7 is manufactured.

  Further, the container main body 10 is taken out from the female mold 42, folded while heating the peripheral edge portion of the sheet to the melting point or higher, and heat-sealed to the outer side surface of the flange portion to form the thermoplastic resin layer 5.

  At this time, since the sheet is used, the thermoplastic resin layer 5 can be formed on the container body 10 without damaging the container body 10.

  The material of the male mold 41 and the female mold 42 is preferably, for example, a metal such as iron, brass, or aluminum. Furthermore, applying the Teflon (registered trademark) coating to the male mold 41 and the female mold 42 facilitates the removal of the container body 10 and the smooth finishing of the surface of the thermoplastic resin layer 5.

  The male mold 41 and the female mold 42 can be heated by various methods. For example, an external heating element such as a gas burner, infrared light, or an electric heater element may be brought into contact with or opposed to the male mold 41 and the female mold 42. In addition, a heated liquid such as oil or a heated gas such as water vapor may be passed through the male mold 41 and the female mold 42 to heat the male mold 41 and the female mold 42.

(3) Application process (see FIG. 12)
A shielding plate 6 having a circular convex portion having a height of 10% or more of the thickness of the flange portion and a diameter slightly larger than the outside of the flange portion is covered from above the container body 10, and the flange portion Cover 10-100% of the outer side.

Thereafter, the waterproof material having heat melting property is heated and melted, and this is applied by a spray method to form the waterproof material layer 3 on the outer surface (including the lower surface of the flange portion) of the container body 10.
At this time, since the shielding plate 6 protrudes along the outer side surface of the flange portion, a waterproof material having heat melting properties is not applied to the upper surface of the flange portion through the gap between the shielding plate 6 and the flange portion. The easy peel property between the flange portion and the lid member 2 is not hindered. Also, by applying in this way, the water-resistant waterproof material can be applied to all surfaces not covered with the water-resistant thermoplastic resin, so there is no place where the starch foam is in contact with the outside air, Problems such as deformation due to moisture do not occur.

  Further, since a waterproof material having heat melting property is used, it can be applied without using water or an organic solvent, and the container body 10 can be deformed by the water that has penetrated the container body 10 or the container body 10 can be deformed. No organic solvent is contained.

(4) Sealing process The lid material 2 was heat-sealed with a hot plate or the like on the upper surface of the flange portion to obtain a biodegradable instant food container 1.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

<Example 1>
(1) Body molding process (see FIGS. 5, 6, 7 and 8)
The container body 10 according to the present invention was molded by the molding apparatus 30. The molding apparatus 30 includes a male mold 31 and a female mold 32. The female die 32 has a plurality of truncated cone-shaped concave portions 33 (upper diameter 94 mm, lower diameter 66 mm, height 109 mm) on the upper surface, and has a rectangular parallelepiped that can separate the concave portions 33 in half. . The male mold 31 has a plate-like shape having a convex part 34 having a truncated cone shape (upper diameter 90 mm, lower diameter 62 mm, height 105 mm) complementary to the concave part 33 of the female mold 32 on the lower surface. The upper portion of the convex portion 34 has a diameter of 100 mm so as to close the concave portion 33 of the female mold 32. Furthermore, four vertical ventilation grooves 35 connected to the molding region are formed in the upper portion of the convex portion 34.

  First, 24.5% by weight of potato starch, 20% by weight of calcium carbonate (trade name: Calfood, manufactured by Maruo Calcium Co., Ltd.), and magnesium stearate in the recess 33 of the female mold 32 of the molding apparatus 30. 25 g of a mixture of 0.5% by weight, 5% by weight of cellulose fibers and 50% by weight of water is supplied. And the convex part 34 of the male metal mold 31 heated to 200 degreeC was inserted in the recessed part 33 of the female metal mold 32 heated to 200 degreeC.

  Next, after the male mold 31 was removed, the excess raw material mixture was removed with a scraper blade. And the female metal mold | die 32 was isolate | separated into two and the container main body 10 was taken out.

  Further, the container body 10 was placed in an oven at 105 ° C. for 1.5 hours to remove moisture from the container body 10.

(2) Resin layer forming step (see FIGS. 9, 10 and 11)
70% by weight of polylactic acid and 30% by weight of biodegradable aromatic polyester are mixed and supplied to an extruder equipped with a T die (trade name: extruded sheet T die, manufactured by Ipros), melt-extruded from the T die, A sheet 7 having a thickness of 150 μm was produced.

  Thereafter, the thermoplastic resin layer 5 according to the present invention was molded by the forming apparatus 40. The forming apparatus 40 includes a male mold 41 and a female mold 42. The female mold 42 has a rectangular parallelepiped shape having a plurality of truncated cone-shaped concave portions (upper aperture 94 mm, lower aperture 66 mm, height 109 mm) on the upper surface, and the inside of the recess 43 can be decompressed. Is formed. The male mold 41 has a plate-like shape having a convex part 44 having a truncated cone shape (upper aperture 80 mm, lower aperture 50 mm, height 100 mm) complementary to the recess 43 of the female mold 42 on the lower surface.

  First, the container body 10 was placed in the recess 43 of the female mold 42. The sheet 7 heated to 130 ° C. is sent out onto the container body 10, and the inside of the recess 43 of the female mold 42 is decompressed and thermocompressed downward by the male mold 41, while the inner surface of the container body 10 and the upper surface of the flange portion A thermoplastic resin layer was formed.

Then, considering the thickness of the flange portion, the sheet 7 was cut into a circle having a larger diameter than the outside of the flange portion, and the container body 10 having the peripheral edge portion of the sheet 7 was produced.
Further, the container body 10 was taken out from the female mold 42, folded while heating the peripheral edge of the sheet 7 to the melting point or higher, and heat-sealed to the outer side surface of the flange portion to form the thermoplastic resin layer 5. .

(3) Application process (see FIG. 12)
A shielding plate 6 having a circular convex portion which is 100% of the thickness of the flange portion and has a slightly larger diameter than the outside of the flange portion is covered from above the container body 10, and the outside of the flange portion. Covered 100% of the sides.

  Thereafter, microcrystalline wax (trade name: Himic 1090, manufactured by Nippon Seiwa Co., Ltd., melting point 85 ° C.) heated to 130 ° C. is applied by a spray method, and the outer surface of the container body 10 (including the lower surface of the flange portion) A waterproof material layer 3 was formed.

(4) Sealing process Cover material 2 (paper (80 μm) / aluminum (7 μm) / mixture of aliphatic polyester and aromatic polyester (50 μm)) on the upper surface of the flange portion with a hot plate at 150 ° C., 0.7 seconds, The container was heat sealed at 4 kg / cm ² to obtain a biodegradable instant food container according to Example 1.

<Example 2>
Instead of the container body 10 in which the thermoplastic resin layer 5 is formed on the upper surface and the outer side surface of the flange portion, a container in which the thermoplastic resin layer 15 is formed on the upper surface, the outer side surface, and the lower surface of the flange portion. The main body 20 was manufactured, and in the coating process, the shielding plate 16 having an opening covering a part of the lower surface of the flange portion was used instead of the shielding plate 6 having the convex portion, and the same procedure as in Example 1 was performed. The biodegradable instant food container according to Example 2 was obtained (see FIG. 13).

<Comparative Example 1>
The biodegradation according to Comparative Example 1 is performed in the same manner as in Example 1 except that a flat plate-shaped shielding plate 26 that covers the upper surface of the flange portion is used in place of the shielding plate 6 having the convex portion in the outer surface coating step. A container for sex instant food was obtained (see FIG. 14).

<Comparative example 2>
Instead of the container body 10 on which the thermoplastic resin layer 5 is formed on the upper surface and the outer side surface of the flange portion, a thermoplastic resin layer 25 is formed on the upper surface of the flange portion, but is formed on the outer side surface. A biodegradable instant food container according to Comparative Example 2 was obtained in the same manner as Example 1 except that a non-container main body was used (see FIG. 15).

<Comparative Example 3>
A thermoplastic resin layer is formed on the upper surface of the flange portion instead of the container body 10 on which the thermoplastic resin layer 5 is formed on the upper surface and the outer side surface of the flange portion, but is not formed on the outer side surface. A biodegradable instant food container according to Comparative Example 3 was obtained in the same manner as Example 2 except that the container body was used.

<Evaluation method>
(1) The knob portion of the easy peel lid was pulled upward with a tensile force of 1 kg. The situation at that time was evaluated. The results are shown in Table 1.
○: Sealed and can be opened well ×: Not sealed or cannot be opened well (2) Safety and deformability Panel 10 hot water from a container body containing hot water (80 ° C, 300 cm ³ ) We had you drink and performed sensory evaluation. Furthermore, it was evaluated whether the container body deformed while drinking hot water. The results are shown in Table 1.
○: The tongue or lips are not damaged and the container body is not deformed. ×: The tongue or lips are sometimes damaged or the container body is deformed. (3) Calcium chloride is contained in the moisture-proof biodegradable instant food container. 50 g, 40 ° C., 90% R.D. H. The amount of water permeated per day was measured from the change in weight when left in the atmosphere. The results are shown in Table 1.
○: Dampproof (less than 80 g / m ² · day.)
×: No moisture resistance (80 g / m ² · day. Or more)
(4) Biodegradability The container body was evaluated according to JIS K6950 “Plastic-Aerobic Biodegradation Test Method Using Activated Sludge”. The results are shown in Table 1.
○: Decomposition ×: Non-decomposition

  In the easy peel property, in the biodegradable instant food container according to Examples 1 and 2, the lid member was peeled off from the container body and opened. On the other hand, in the container main body according to Comparative Example 1, since the waterproof material was applied to the upper surface of the flange portion through the gap between the shielding plate and the flange portion, the lid material was peeled off from the container main body and further opened. In addition, the sealing was insufficient.

  In terms of safety and deformability, the container body according to Examples 1 and 2 did not damage the tongue or lips. On the other hand, in the container body according to Comparative Examples 2 and 3, the starch on the outer side surface of the flange portion is softened during eating, and the end of the thermoplastic resin layer may hurt the tongue or lips, and further to a part of the container body Since the waterproof material was not applied, the container body deformed when stored for a long time in high humidity conditions.

It is a perspective view which shows an example of the container for biodegradable instant foods of this invention. FIG. 2 is a cross-sectional view (partially a side view) taken along line AA in FIG. 1. It is an expanded sectional view of B of FIG. It is an expanded sectional view showing some other examples of the biodegradable instant food container of the present invention. It is a perspective view which shows an example of the shaping | molding apparatus which can manufacture the container main body which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is sectional drawing which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is a partial expanded sectional view which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is a partial expanded sectional view which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on this invention. It is a partial expanded sectional view which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on a comparative example. It is a partial expanded sectional view which shows an example of the process of the manufacturing method of the biodegradable instant food container which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Biodegradable instant food container 2 12 Cover material 3, 13 Waterproof material layer 4, 14 Container main body 5, 15, 25 Thermoplastic resin layer 6, 16, 26 Shield plate 7 Sheet 10, 20 Container main body 30 Molding apparatus 31, 41 Male molds 32, 42 Female molds 33, 43 Concave portions 34, 44 Convex portions 35 Ventilation grooves 36 Nozzle 40 forming apparatus

Claims (7)

A bottom plate portion and a peripheral wall portion provided at the periphery of the bottom plate portion, and a flange portion has a predetermined distance from the opening edge toward the outside at a top end of the peripheral wall portion, and has a predetermined thickness. A container body made of starch foam, formed to have,
A biodegradable instant food container comprising a lid that seals the inside of the container body by being adhered to the upper surface of the flange portion,
A thermoplastic resin layer having water resistance and biodegradability is formed on the inner surface of the container body and at least the upper surface and the outer side surface of the flange portion,
A biodegradable instant food container, wherein an outer surface of the container main body is coated with a waterproof material having biodegradability and heat melting property. The biodegradable instant food container according to claim 1, wherein the starch foam is coated with the thermoplastic resin layer and the waterproof material so that there is no portion where the starch foam is exposed to the outside air. The thermoplastic resin layer contains at least one selected from the group consisting of polyadipate, polylactone, polylactic acid, polyglycolic acid, poly β-hydroxybutyric acid, and aromatic polyester. Biodegradable instant food container. The biodegradable instant food according to any one of claims 1 to 3, wherein the waterproof material is at least one selected from the group consisting of low-molecular natural resins, waxes, fatty acids, fats and oils, and derivatives thereof. container. A bottom plate portion and a peripheral wall portion provided at the periphery of the bottom plate portion, and a flange portion has a predetermined distance from the opening edge toward the outside at a top end of the peripheral wall portion, and has a predetermined thickness. A container body made of starch foam, formed to have,
A method for producing a biodegradable instant food container comprising a lid that seals the inside of the container body by being adhered to the upper surface of the flange portion,
A main body molding process in which a raw material mainly composed of starch is foamed and molded into a container main body,
A resin layer forming step of forming a thermoplastic resin layer having water resistance and biodegradability on the inner surface of the container body and at least the upper surface and the outer side surface of the flange portion;
An application step of applying a biodegradable and heat-meltable waterproof material to the outer surface of the container body while covering all or part of the outer side surface of the flange portion with a shielding plate having a convex portion,
A method for producing a biodegradable instant food container, comprising: a sealing step of sealing the inside of the container body by adhering the lid material to the upper surface of the flange portion. A bottom plate portion and a peripheral wall portion provided at the periphery of the bottom plate portion, and a flange portion has a predetermined distance from the opening edge toward the outside at a top end of the peripheral wall portion, and has a predetermined thickness. A container body made of starch foam, formed to have,
A method for producing a biodegradable instant food container comprising a lid that seals the inside of the container body by being adhered to the upper surface of the flange portion,
A main body molding process in which a raw material mainly composed of starch is foamed and molded into a container main body,
A resin layer forming step of forming a thermoplastic resin layer having water resistance and biodegradability on the inner surface of the container body and the upper surface, outer side surface, and lower surface of the flange portion,
An application step of applying a waterproof material having biodegradability and heat melting property to the outer surface of the container body while covering all or part of the lower surface of the flange portion with a shielding plate having an opening;
A method for producing a biodegradable instant food container, comprising: a sealing step of sealing the inside of the container body by adhering the lid material to the upper surface of the flange portion.   In the resin layer forming step, after a sheet including the thermoplastic resin layer is molded, a thermoplastic resin layer is formed on the inner surface of the container body and at least the upper surface and the outer side surface of the flange portion using the sheet. A method for producing a biodegradable instant food container according to claim 5 or 6.

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