JP4796654B1 - Biodegradable container manufacturing method and biodegradable container manufactured by the method - Google Patents

Abstract

The present invention provides a method for producing a biodegradable container that does not generate a surplus of biodegradable material when the biodegradable material is fired by steam foaming.
A method of manufacturing a biodegradable container uses a foam molding mold comprising a pair of male and female molds that can be fitted with a heater and interposes a biodegradable material containing moisture. Then, a male and female molds are fitted together, and a biodegradable material is heated in a mold, steam-foamed and fired to form a container-like foamed base material layer having a bottom part, a body part and an opening edge part. A male mold and a female mold each having a contact portion that forms a first steam vent when they are fully fitted, and a second steam vent is formed on at least one of the molds. The step of heating the biodegradable material within the pre-fitting of the male mold and the female mold for a predetermined time so that the abutting portions of the male mold and the female mold face each other with a predetermined gap therebetween The first and second steam vent holes are formed by completely fitting the male mold and the female mold so that the abutting portions abut each other. A step of firing while dissipating water vapor.
[Selection] Figure 8

Description

  The present invention relates to a method for producing a biodegradable container and a biodegradable container produced by the method, and more particularly, a method for producing a biodegradable container by foaming a biodegradable material and the method. It relates to a biodegradable container.

  As a prior art related to the present invention, a pair of male mold and female mold is formed by using a foaming mold comprising a pair of male mold and female mold with a built-in heater, and interposing a biodegradable material containing moisture. The mold is fitted, the biodegradable material is heated in the mold and steam-foamed, and the biodegradable material is baked while dissipating water vapor from the vent holes formed in the upper, side and lower parts of the female mold. A method for producing a biodegradable container for obtaining a container-like foamed base material layer is known (see, for example, Patent Document 1).

  In addition, as a related art related to the present invention, after placing a container made of a pulp fiber layer on a mold capable of evacuation, a resin film is arranged above the container, and the resin film is placed with a plug provided with a heater. There is known a manufacturing method of a heat insulating container in which an inner surface of a container is covered with a resin film by evacuating through the pulp fiber layer of the container while being pushed into the container (see, for example, Patent Document 2).

Korean Patent No. 10-0866940 Japanese Patent No. 4039908

In response to growing environmental awareness in recent years, such as the reduction of carbon dioxide and the establishment of a resource recycling society, products that do not rely on petroleum resources are also required in the field of disposable containers.
Under such circumstances, biodegradable containers using plant-derived biomass as a raw material have attracted attention. Plant-derived biomass absorbs carbon dioxide in the atmosphere and grows. Therefore, even if carbon dioxide is discharged during biodegradation or incineration after disposal, it is absorbed by the raw material biomass. It was discharged into the atmosphere again, and the total amount of carbon dioxide in the atmosphere does not increase from the total production to disposal. Such a property is called carbon neutral and is an important keyword when considering environmental issues.

  Biodegradable containers made from biomass have been proposed in which the inner surface of a foamed substrate layer obtained by foaming and firing a biodegradable material made mainly from starch is covered with a water-resistant film. . In other words, the foamed base material layer is a porous baked product made of starch as a main raw material, so it absorbs water and dissolves easily in water. However, if at least the inner surface of the container is covered with a water-resistant film, It can be used similarly.

  As a method for manufacturing such a biodegradable container, a mold for foam molding comprising a pair of male mold and female mold equipped with a heater is used, and a male mold and a female mold are interposed with a biodegradable material interposed. After fitting and forming the container-shaped foam base material layer by heating the biodegradable material in the mold, foaming it with water vapor and firing it, the resulting foam base material layer can be vacuum drawn together with the water resistant film. A method of covering the inner surface of the foamed substrate layer with a water-resistant film by placing it in a possible mold and drawing a vacuum through the foamed substrate layer is common.

In the above method, when the biodegradable material is heated and steam-foamed and fired in the mold, the steam is diffused to the outside from a plurality of steam vent holes formed in the contact portion of the male mold and the female mold. While firing. At this time, the surplus of the steam-decomposable biodegradable material blows out from the steam vent hole and solidifies in a state where it is connected to the opening edge of the foam base material layer.
For this reason, before installing the obtained foam base material layer in a mold for vacuuming, it is necessary to cut off the excess connected to the opening edge portion in advance, which causes the productivity of the biodegradable container to deteriorate It has become one of the.

  The present invention has been made in consideration of the above circumstances, and a method for producing a biodegradable container that does not generate a surplus of biodegradable material when the biodegradable material is foamed with water vapor and fired. Is to provide.

  The present invention uses a mold for foam molding consisting of a pair of male and female molds that can be fitted with a heater, and mates the male and female molds with a biodegradable material containing moisture. And heating the biodegradable material in a mold, steam-foaming and firing to form a container-shaped foam base material layer having a bottom, a body and an opening edge, and a male mold and a female mold Each has a contact portion that forms a first steam vent when they are completely fitted together, and a second steam vent is formed in at least one of them to heat the biodegradable material in the mold. In the step, the male part and the female mold are preliminarily fitted with each other for a predetermined time so that the male part and the female part are opposed to each other with a predetermined interval, and then the abutting part comes into contact with each other. In this way, the male mold and female mold are completely fitted, and the water vapor is dissipated from the first and second vapor vent holes while firing. There is provided a method for producing a biodegradable container, characterized in that the step of.

According to the present invention, the male mold and the female mold are completely fitted to each other after the male mold and the female mold are preliminarily fitted to each other for a predetermined time so that moisture contained in the biodegradable material is appropriately dissipated. The amount of moisture contained in the biodegradable material in the mold when the male mold and the female mold are completely fitted is smaller than that in the prior art.
Since the increase in the internal pressure in the mold due to steam foaming of the biodegradable material is proportional to the amount of moisture contained in the biodegradable material, in the present invention, in the mold when the biodegradable material is steam foamed. The increase in the internal pressure of is moderately suppressed.
For this reason, the force which pushes out biodegradable material from a steam vent hole becomes weaker than before.

In addition, since the amount of moisture contained in the biodegradable material in the mold when the male mold and female mold are completely fitted is smaller than before, the absolute amount of water vapor that diffuses from the mold to the outside during firing The amount is also reduced.
For this reason, the cross-sectional area of the steam vent hole required to dissipate the water vapor can be set small, and in the present invention, the first steam vent hole and the second steam vent hole are provided in a distributed manner. The cross-sectional area of each of the punch holes can be set so small that the biodegradable material does not blow out.

Then, in a state where moisture contained in the biodegradable material is reduced and the internal pressure in the mold is moderately suppressed, firing is performed while dissipating water vapor from both the first and second vapor vent holes having a small cross-sectional area. By doing so, the biodegradable material can be satisfactorily fired while preventing surplus of the biodegradable material from being blown out from the vapor vent hole.
As a result, the biodegradable container can be manufactured with high productivity without generating surplus of the biodegradable material.

It is a perspective view of the biodegradable container manufactured by the manufacturing method which concerns on embodiment of this invention. It is AA arrow sectional drawing of the biodegradable container shown by FIG. It is an enlarged view of the B section of FIG. It is an enlarged view of the C section of FIG. It is a perspective view of the metal mold | die for foam molding used for the manufacturing method which concerns on embodiment of this invention. It is DD sectional drawing of the metal mold | die shown by FIG. It is sectional drawing which shows the state which the metal mold | die shown by FIG. 6 fitted. It is process drawing explaining the manufacturing method of the biodegradable container which concerns on embodiment of this invention. It is process drawing explaining the manufacturing method of the biodegradable container which concerns on embodiment of this invention. It is process drawing explaining the manufacturing method of the biodegradable container which concerns on embodiment of this invention. It is process drawing explaining the manufacturing method of the biodegradable container which concerns on embodiment of this invention. It is an enlarged view of the E section of Drawing 10 (f).

  The method for producing a biodegradable container according to the present invention uses a foam molding mold comprising a pair of male and female molds that can be fitted with a heater, and interposes a biodegradable material containing moisture. A step of forming a container-like foamed base material layer having a bottom part, a body part, and an opening edge part by fitting a male mold and a female mold, heating a biodegradable material in a mold, steam-foaming and firing The male mold and the female mold each have a contact portion that forms a first steam vent when they are fully fitted to each other, and at least one of the second steam vent is formed in the mold. In the step of heating the biodegradable material, the male mold and the female mold are preliminarily fitted with each other for a predetermined time so that the male mold and the female mold are opposed to each other with a predetermined interval. The first and second steam vent holes are formed by completely fitting the male mold and the female mold so that the abutting portions abut each other. Characterized in that it is a step of firing while dissipating Luo steam.

  In the biodegradable container manufacturing method according to the present invention, the foam molding mold comprising a pair of matable male and female molds with a built-in heater has a cavity corresponding to the shape of the container at the time of mating. It means a mold that is formed and configured so that gas or water vapor generated when the biodegradable material is heated and foamed in the cavity can be appropriately discharged to the outside. A heater is provided for each of the male mold and the female mold to maintain the mold at a desired temperature.

The abutting portion means a portion where the male mold and the female mold are in contact with each other when the male mold and the female mold are completely fitted, thereby positioning the male mold and the female mold and forming a first steam vent hole that communicates with the cavity. A mold and a female mold are formed respectively.
The first vapor vent hole means a passage that is formed by the male and female abutting portions and diffuses gas and water vapor generated in the cavity to the outside.
The second vapor vent hole is formed in at least one of the male mold and the female mold, and means a passage for dissipating gas and water vapor generated in the cavity to the outside like the first vapor vent hole.

  The biodegradable material means a material for the foam base material layer that forms the skeleton of the biodegradable container, and is prepared by containing moisture so that it can be molded with a mold for foam molding.

In the biodegradable container manufacturing method according to the present invention, the male mold may be formed with a plurality of longitudinal grooves extending toward the abutting portion on the surface of the portion corresponding to the body portion of the foamed base material layer.
According to such a configuration, the water vapor remaining between the mold and the foamed base material layer being fired can be guided to the vicinity of the first vapor vent hole and diffused to the outside from the first vapor vent hole. .
This improves the adhesion between the mold and the foamed base material layer during firing, and not only accurately reproduces the shape of the mold, but also makes the surface of the foam base material layer very smooth.

  In the method for producing a biodegradable container according to the present invention, the female mold may be formed with pleated irregularities extending toward the contact portion on the surface of the portion corresponding to the body portion of the foam base layer.

According to such a configuration, the thick and thin portions are alternately formed in the portion corresponding to the body portion by the pleated unevenness formed in the female mold, so that biodegradability in the mold is achieved. The rapid flow of the material is suppressed, and it is possible to prevent the biodegradable material from suddenly extending and tearing when the biodegradable material is fully poured into the mold.
Thereby, the preferable effect that it can prevent that a partial crack is produced in a foaming base material layer by defective filling is acquired.

In the method of manufacturing a biodegradable container according to the present invention, the first steam vent hole is formed by being divided into a plurality of first steam vent holes by a gap partially formed in the contact portion between the male mold and the female mold. Also good.
According to such a configuration, since the first steam vent hole is formed by being divided into a plurality of first steam vent holes, each first steam vent hole has an appropriate size and shape that prevents the biodegradable material from overflowing. It becomes easy to design.

In the method for producing a biodegradable container according to the present invention, the female mold is composed of a plurality of mold pieces, and the second steam vent hole is along the edge of the portion corresponding to the bottom of the foam base material layer by the gap between the adjacent mold pieces. It may be formed in an annular shape.
According to such a configuration, the second steam vent hole is along the edge of the portion corresponding to the bottom portion of the foam base material layer that is separated from the first steam vent hole formed in the contact portion between the male mold and the female mold. Therefore, the water vapor in the mold can be dissipated uniformly, and the internal pressure in the mold can be effectively suppressed.

  In the method for producing a biodegradable container according to the present invention, the predetermined time for preliminarily fitting the male mold and the female mold can be in the range of about 3 to 15 seconds.

In other words, if the time for pre-mating the male mold and female mold becomes too short, it becomes difficult to dissipate the moisture contained in the biodegradable material to an appropriate amount in advance, and the male mold and female mold are completely separated. The water contained in the biodegradable material cannot be sufficiently dissipated from the first and second steam vent holes in the step of fitting and firing, and there is a risk that the foamed base material layer will be burnt.
On the other hand, if the time for pre-mating the male mold and female mold becomes too long, the moisture contained in the biodegradable material is dissipated more than necessary, and the male mold and female mold are completely fitted. In some cases, the amount of moisture contained in the biodegradable material is too small, and the internal pressure in the cavity is not sufficiently increased, and the foam base material layer may be partially chipped due to poor filling of the biodegradable material.
From this point of view, there is an appropriate range for the time for which the male mold and female mold are preliminarily fitted, and depending on the amount of moisture contained in the biodegradable material and the temperature of the mold, About 3 to 15 seconds can be said to be an appropriate range for the fitting time.

In the method for producing a biodegradable container according to the present invention, the biodegradable material may be a kneaded product obtained by kneading at least starch, pulp and water.
According to such a configuration, since starch and pulp, which are plant-derived materials, are the main raw materials, a biodegradable container having excellent biodegradability and low environmental impact can be produced.

Here, starch means starch or a derivative thereof, and is not particularly limited. For example, potato, corn, tapioca, rice, wheat, sweet potato, and other agricultural products that are produced worldwide as main grains. The starch obtained from can be mentioned, The thing manufactured from the specific agricultural product may be used, and the thing manufactured from the several agricultural products may be mixed.
Further, the starch derivatives mentioned above refer to those obtained by modifying starch within a range that does not inhibit biodegradability, and examples thereof include pregelatinized starch, crosslinked starch, and modified starch.
Furthermore, a mixture obtained by mixing the unmodified starch and the starch derivative may be used.

  The pulp means an aggregate of plant-derived fibers and is not particularly limited, and examples thereof include wood pulp and non-wood pulp.

  From another viewpoint, the present invention also provides a biodegradable container manufactured by the above-described manufacturing method according to the present invention.

  From another viewpoint, the present invention uses a biodegradable container manufactured by the above-described manufacturing method according to the present invention, and arranges the container in a mold that can be evacuated and above the container. Production of a biodegradable container comprising a step of covering the inner surface and the opening edge of the foamed base material layer with the water resistant film by placing a water resistant film and evacuating the foamed base material layer of the container It also provides a method.

  In the present invention, as described above, since the biodegradable container can be produced without generating the surplus overflowed from the steam vent, it is necessary to cut off the surplus when the produced biodegradable container is placed in the mold. Therefore, the coating process can be performed efficiently.

  In addition, in the above-mentioned present invention in which the inner surface of the foam base material layer is coated with a water resistant film, the water resistant film may be any material that can impart water resistance to the surface of the foam base material layer. It doesn't matter. Therefore, in the present invention, as the water resistant film, a biodegradable film made of biodegradable plastic or a non-biodegradable film made of ordinary plastic can be used.

  From another viewpoint, the present invention is a biodegradable container manufactured by the above-described manufacturing method according to the present invention, wherein the inner surface and the opening edge are covered with a water-resistant film. It is also what provides.

  Hereinafter, the manufacturing method of the biodegradable container which concerns on embodiment of this invention based on drawing is demonstrated. In addition, in the several embodiment demonstrated below, the same code | symbol is attached | subjected and demonstrated to the same member.

  The manufacturing method of the biodegradable container which concerns on embodiment of this invention is demonstrated based on FIGS. 1 is a perspective view of a biodegradable container manufactured by a manufacturing method according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is an enlarged view of a portion B in FIG. It is the C section enlarged view of FIG.

1-4, the biodegradable container 1 manufactured by the manufacturing method which concerns on embodiment of this invention has the bottom part 2a, the trunk | drum 2b, and the opening edge part 2c, and the biodegradable container 1 of FIG. It is comprised from the container-like foaming base material layer 2 which makes | forms frame | skeleton, and the water resistant film 3 which coat | covers the inner surface 2d of the foaming base material layer 2, and the opening edge part 2c.
The foamed base material layer 2 is provided with water resistance by covering the inner surface 2d and the opening edge 2c with a water resistant film 3, and is used with hot water or the like due to the excellent heat insulating property of the foamed base material layer 2. Is also possible.

As shown in FIG. 2, in this embodiment, the opening edge 2c of the foam base material layer 2 has a diameter R1 of about 151 mm and a thickness T1 of about 2 mm. Moreover, height H1 from the bottom part 2a of the foaming base material layer 2 to the opening edge part 2c is 74.8 mm.
As shown in FIG. 1, pleated irregularities 2f extending from the bottom 2a toward the opening edge 2c are formed on the outer surface of the body 2b of the foam base material layer 2. As a result, thick portions and thin portions are alternately formed on the body portion 2b. The thick portion T2 shown in FIG. 2 has a thickness T2 of about 2 mm, and the thin portion has a thickness T3 of about 1.5 mm. Further, the thickness T4 of the bottom 2a is about 2 mm.

A foam molding die used in the method for producing the biodegradable container 1 shown in FIG. 1 will be described with reference to FIGS. 5 is a perspective view of a mold used in the method for manufacturing a biodegradable container according to the embodiment of the present invention, FIG. 6 is a cross-sectional view of the mold shown in FIG. It is sectional drawing which shows the state which the metal mold | die shown by FIG. Fits.
As shown in FIGS. 5 to 7, in this embodiment, for foam molding comprising a pair of male mold 4 and female mold 5 for forming a cavity 10 (see FIG. 7) corresponding to the shape of the container to be molded. The mold 6 is used. The male mold 4 and the female mold 5 incorporate an electric heater (not shown), and both are maintained at about 200 ° C. in the molding process of the foam base material layer 2 described later.

As shown in FIGS. 5 and 6, the male mold 4 and the female mold 5 have contact portions 4 a and 5 a that contact each other when completely fitted. A groove-shaped recess 5b is formed.
When the contact portions 4a and 5a contact each other, ten slit-shaped first steam vent holes 11 (see FIG. 7) that lead to the cavity 10 corresponding to the concave portions 5b are formed on the opening edge portion 2c of the foam base material layer 2. It is formed so as to face the end face 2e (see FIGS. 1 and 2).
As shown in FIG. 5, each recess 5b has a width W1 of 16 mm and a height H2 of 0.2 mm. Therefore, each first steam vent 11 has a cross-sectional area of 3.2 mm ² .

As described above, since the opening edge 2c has a diameter R1 of 151 mm and a thickness T1 of 2 mm, the surface area of the end surface 2e of the opening edge 2c is 948.28 mm ² .
On the other hand, since the cross-sectional area of each first vapor vent hole 11 is 3.2 mm ² as described above, the total cross-sectional area of the ten first vapor vent holes 11 is 32 mm ² .
Therefore, the ratio of the total cross-sectional area of the first vapor vent hole 11 to the surface area of the end face 2e of the opening edge 2c is about 3.4%, which is a lower value than before. That is, in this embodiment, in order to prevent the surplus portion of the biodegradable material 7 from being blown out through the first steam vent hole 11, the cross-sectional area is set smaller than the conventional one, and the steam is difficult to escape.

Therefore, in order to assist the first steam vent hole 11 having a small cross-sectional area, the second steam vent hole 12 is also provided along the periphery of the bottom 5c of the female die 5 in this embodiment as shown in FIGS. Is formed in a ring shape.
The second steam release hole 12 is formed by a gap between the mold pieces 8 and 9 constituting the female mold 5, and has an outer diameter R2 of 75.6 mm and an inner diameter R3 of 75.4 mm. The cross-sectional area of the second steam vent hole 12 is 23.7 mm ² , which is smaller than the total cross-sectional area of the first steam vent hole 11, and the steam does not escape well.

As described above, in this embodiment, the second steam vent hole 12 is formed in addition to the first steam vent hole 11, but all of them have a very small cross-sectional area, and the escape of steam is never good.
Therefore, in the present embodiment, as shown in FIG. 5, 16 vertical grooves 4d extending from the periphery of the bottom 4c toward the contact portion 4a are formed at equal intervals around the side 4b on the side 4b of the male mold 4. The water vapor remaining between the surface of the cavity 10 and the foamed base material layer 2 being fired is guided to the vicinity of the first vapor vent hole 11.

As shown in FIGS. 5 and 6, the female mold 5 has a pleat-shaped unevenness 5e extending vertically from the bottom 5c toward the contact portion 5a on the side surface 5d corresponding to the body portion 2b of the foam base material layer 2. Is formed. That is, the pleated unevenness 5e alternately forms a portion having a large gap and a portion having a small gap in the cavity 10.
Thereby, when the male mold 4 and the female mold 5 are fitted, the biodegradable material 7 is prevented from flowing rapidly in the cavity 10, and when the biodegradable material 7 extends in the cavity 10. It is prevented from tearing.

  Hereinafter, a method for manufacturing the biodegradable container 1 according to the present embodiment using the above-described mold 6 will be described with reference to FIGS. FIGS. 8-11 is process drawing explaining the manufacturing method of the biodegradable container which concerns on embodiment of this invention, FIG. 12 is an enlarged view of the E section of FIG.10 (f).

First, as shown in FIG. 8A, the biodegradable material 7 is put into the bottom of the female mold 5. The biodegradable material 7 is obtained by mixing starch with a melt of pulp and water, and then heat-treating it. In this embodiment, the ratio (moisture value) of water to the biodegradable material 7 is 50 to 65% by weight, and the property of the biodegradable material 7 is a dough shape having no fluidity in a non-pressurized state.
The biodegradable material 7 may be mixed with a slight amount of a release agent in order to enhance the releasability from the fired mold 6. As the mold release agent, glycerin fatty acid ester, vegetable oil, magnesium stearate, calcium stearate and the like can be used.

Then, as shown in FIG. 8 (b), the male mold 4 and the female mold 5 are placed in a 6 second period so that the contact portions 4a, 5a of the male mold 4 and the female mold 5 face each other with a gap D1 of about 5 mm. Preliminarily fit to the extent.
At this time, the biodegradable material 7 is heated while flowing in the gap between the male mold 4 and the female mold 5 that are preliminarily fitted, and a part of the water contained in the biodegradable material 7 is converted into water vapor to form the male mold. It is dissipated outside through the gap between 4 and the female mold 5.

Next, as shown in FIG. 9 (c), the male mold 4 and the female mold 5 are completely fitted, and the biodegradable material is heated in the mold 6 maintained at about 200 ° C. by the heater, thereby Foam and fire for about 80 seconds.
During the firing, water vapor generated from the biodegradable material 7 is diffused to the outside from both the first and second steam vent holes 11 and 12, but as described above, the first and second steam vent holes 11, No. 12 has a very small cross-sectional area, and the escape of steam is not good.
However, the amount of moisture contained in the biodegradable material 7 itself is reduced by the previous process of preliminarily fitting the male mold 4 and the female mold 5, and the heating when preliminarily fitted. As a result, the temperature of the biodegradable material 7 is increased. As soon as the biodegradable material 7 is fitted, the foaming of water vapor starts and the internal pressure in the cavity 10 (see FIG. 7) increases rapidly. Most of the water contained in the biodegradable material 7 can be dissipated at the stage.

In addition, the biodegradable material 7 that is steam-foamed during the firing does not blow out from the first and second steam vent holes 11 and 12.
This is because, as described above, since the first and second vapor vent holes 11 and 12 have a very small cross-sectional area, the water-foamed biodegradable material 7 is physically formed by the first and second vapor vent holes 11. 12, and the amount of moisture contained in the biodegradable material 7 is reduced in the previous step of preliminarily fitting the male mold 4 and the female mold 5. This is because the internal pressure in the cavity 10 is not increased to the extent that the biodegradable material 7 is pushed out from the first and second vapor vent holes 11 and 12 to an appropriate extent.

  Further, as described above, the pleated irregularities 5e (see FIG. 5) are formed on the side surface 5d of the female die 5, so that the biodegradable material 7 is prevented from flowing and tearing at the time of steam foaming. The degradable material 7 is properly filled in the cavity 10.

  Next, as shown in FIG. 9D, the mold 6 is opened and the fired foamed base material layer 2 is taken out. The taken-out foam base material layer 2 is shipped as a biodegradable container as long as the water resistance is not required because the surplus of the biodegradable material 7 is not generated at the opening edge 2c. Is also possible. However, in this embodiment, in order to impart water resistance to the foam base material layer 2, the inner surface 2 d and the opening edge 2 c of the foam base material layer 2 are covered with the water resistance film 3.

First, as shown in FIG. 10 (e), a mold 15 that can be evacuated after an adhesive is applied to the inner surface 2d and the opening edge 2c of the foamed base material layer 2 obtained through the above-described steps. To place. The mold 15 is composed of an upper mold 13 and a lower mold 14, and the foamed base material layer 2 coated with an adhesive is disposed on the lower mold 14. At this time, as described above, since the surplus portion of the biodegradable material 7 is not generated in the opening edge portion 2c of the foam base material layer 2, the mold 15 is not subjected to post-treatment such as cutting off the surplus portion. Can be placed.
After disposing the foam base material layer 2 on the lower mold 14, the water resistant film 3 is disposed between the upper mold 13 and the lower mold 14, and is heated to about 155 to 180 ° C. by radiant heat from hot air or a heater (not shown). Preheated.
The water-resistant film 3 is a biodegradable aromatic polyester resin (Apexa (registered trademark)) biaxially stretched and formed into a film having a thickness of about 50 μm and has biodegradability.

Next, as shown in FIG. 10 (f) and FIG. 11 (g), the upper mold 13 and the lower mold 14 are fitted and evacuated through the foam base material layer 2. The foam base material layer 2 is a fired product obtained by firing the biodegradable material 7 by steam foaming and has air permeability, so that a negative pressure is instantaneously generated between the foam base material layer 2 and the water-resistant film 3 by evacuation. The water-resistant film 3 softened by preheating quickly adheres to the inner surface 2d of the foam base material layer 2 and the opening edge 2c.
At this time, as shown in FIG. 12, the space formed between the back side of the opening edge 2c and the lower mold 14 also becomes negative pressure by evacuation, and the water-resistant film 3 softened by preheating has a negative pressure. It is made to extend | stretch by this and it adheres also to the back side of the opening edge part 2c.

  Thereafter, as shown in FIG. 11 (h), the mold 15 is opened, and the foamed base material layer 2 in which the inner surface 2d and the opening edge 2c are covered with the water-resistant film 3 is taken out, and on the back side of the opening edge 2c. Then, the water-resistant film 3 is cut to complete the biodegradable container 1 shown in FIGS.

  Thus, in this embodiment, since the foaming base material layer 2 can be shape | molded without generating the surplus part of the biodegradable material 7 in the opening edge part 2c of the foaming base material layer 2, after cutting off the surplus part, etc. It is possible to smoothly shift from the molding process of the foam base material layer 2 to the coating process of the water-resistant film 3 without performing the treatment, and the biodegradable container 1 can be manufactured with high productivity.

  In the present embodiment, the water-resistant film 3 having biodegradability is used, but a film having no biodegradability may be used as the water-resistant film 3.

Comparative Example 1
As Comparative Example 1 for the embodiment of the present invention, an example in which the step of preliminarily fitting the male mold 4 and the female mold 5 is omitted will be described.
When the step of preliminarily fitting the male mold 4 and the female mold 5 is omitted, the male mold 4 and the female mold 5 are completely fitted while the biodegradable material 7 contains a large amount of moisture. Water vapor cannot be sufficiently dissipated from the first and second steam vent holes 11 and 12 having a small cross-sectional area so that the decomposable material 7 does not blow out, and the first and second steam vent holes 11 and 12 Only the vicinity of 12 is fired, and the other parts are burnt.

When this phenomenon is described in detail, since the step of preliminarily fitting the male mold 4 and the female mold 5 is omitted, the temperature of the biodegradable material 7 when the male mold 4 and the female mold 5 are completely fitted is determined. Is lower than in the above embodiment.
For this reason, the time from when the male mold 4 and the female mold 5 are fitted to when the steam foaming starts is longer than that in the above-described embodiment, and the firing is effective for removing moisture contained in the biodegradable material 7. A lot of moisture cannot be removed in the initial stage.

Further, as the moisture contained in the biodegradable material 7 is released, the internal pressure in the cavity 10 starts to decrease, and the force for pushing the moisture to the outside weakens, so the first steam vent hole and the second steam vent hole Baking proceeds only in the vicinity of 11 and 12.
When the firing proceeds only in the vicinity of the first and second vapor vent holes 11 and 12, the moisture diffusion path contained in the other portions becomes blocked by the fired portion, and the moisture becomes difficult to escape. Falls into a vicious circle.

And since baking advances unstablely, a water | moisture content remains locally even in the part which baking advanced, and a crater-like unevenness | corrugation generate | occur | produces.
From the above, it can be seen that provision of a step of preliminarily fitting the male mold 4 and the female mold 5 is effective in firing without generating surplus of the biodegradable material.

Comparative Example 2
As Comparative Example 2 for the embodiment of the present invention, an example in which the time for preliminarily fitting the male mold 4 and the female mold 5 is extended to 20 seconds will be described.
If the time for pre-mating the male mold 4 and the female mold 5 is extended to 20 seconds, the amount of moisture contained in the biodegradable material 7 at the time when the male mold 4 and the female mold 5 are completely fitted is increased. The internal pressure does not increase sufficiently in the cavity 10 because the pressure is too small.
For this reason, the force for filling the biodegradable material 7 into the cavity 10 is weakened, the biodegradable material 7 is not filled into the cavity 10, and the foam base material layer 2 is chipped.

In addition, since the internal pressure in the cavity 10 is not sufficiently increased, the shape of the cavity 10 is not clearly reproduced in the foamed base material layer 2, and a slight firing unevenness occurs on the entire surface.
Furthermore, while the male mold 4 and the female mold 5 are preliminarily fitted, the portion of the biodegradable material 7 that is in contact with the bottom 5d of the female mold 5 is partially fired in advance. Severe baking unevenness occurs in this part.
From the above, it can be seen that there is a certain appropriate range for the time for which the male mold 4 and the female mold 5 are preliminarily fitted.

DESCRIPTION OF SYMBOLS 1 Biodegradable container 2 Foaming base material layer 2a, 4c, 5c Bottom part 2b Trunk part 2c Opening edge part 2d Inner surface 2e End surface 2f, 5e Concavity and convexity 3 Water resistant film 4 Male type | mold 4a, 5a Contact part 4b, 5d Side surface 4d Vertical Groove 5 Female mold 5b Recess 6 Mold 7 Biodegradable material 8, 9 Mold piece 10 Cavity 11 First steam vent 12 Second steam vent 13 Upper mold 14 Lower mold 15 Mold

Claims (10)

  Using a mold for foam molding consisting of a pair of matable male and female molds with a built-in heater, the male mold and female mold are fitted together with a biodegradable material containing moisture. It has a process of forming a container-like foaming base material layer having a bottom, a body part and an opening edge by heating a biodegradable material, steam-foaming and firing within, and the male and female molds are completely fitted The steps of heating the biodegradable material in the mold, each having a contact portion that forms a first steam vent when they are joined together, and a second steam vent is formed in at least one of the two, The male mold and the female mold are preliminarily fitted with each other for a predetermined time so that the male mold and the female mold are opposed to each other with a predetermined gap, and then the male mold is formed so that the abutting sections are in contact with each other. In the process of firing while completely fitting the female mold and the first and second steam vent holes to dissipate water vapor. Method for producing a biodegradable container characterized by Rukoto.   The method for producing a biodegradable container according to claim 1, wherein the male mold is formed with a plurality of vertical grooves extending toward the contact portion on the surface of the portion corresponding to the body portion of the foam base material layer.   The method for producing a biodegradable container according to claim 1 or 2, wherein the female mold is formed with pleated irregularities extending toward the contact portion on the surface of the portion corresponding to the body portion of the foamed base material layer.   The first steam vent hole is formed by dividing the first steam vent hole into a plurality of first steam vent holes by a gap partially formed at the contact portion between the male mold and the female mold. Of manufacturing biodegradable container.   The female mold is composed of a plurality of mold pieces, and the second steam vent is formed in an annular shape along the edge of the portion corresponding to the bottom of the foam base material layer by the gap between the adjacent mold pieces. The manufacturing method of the biodegradable container as described in any one.   The method for producing a biodegradable container according to any one of claims 1 to 5, wherein a predetermined time for preliminarily fitting the male mold and the female mold is within a range of 3 to 15 seconds.   The method for producing a biodegradable container according to any one of claims 1 to 6, wherein the biodegradable material is a kneaded product obtained by kneading at least starch, pulp and water.   A biodegradable container manufactured by the method according to claim 1.   Using the biodegradable container manufactured by the method according to any one of claims 1 to 7, the container is placed in a mold that can be evacuated and a water-resistant film is placed above the container. And the manufacturing method of a biodegradable container provided with the process of coat | covering the inner surface and opening edge part of a foaming base material layer with the said water-resistant film by evacuating through the foaming base material layer of the said container.   A biodegradable container manufactured by the method according to claim 9, wherein the inner surface and the opening edge are covered with a water-resistant film.

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