KR100632636B1 - Apparatus and method to form starch bowl using mold having vent hole - Google Patents

Abstract

The present invention provides a starch container forming apparatus and a starch container forming method using a mold having a vent hole for discharging the gas or foamed surplus for the starch container generated during the heat press molding of the starch container composition during the molding process. In addition, it is preferable to form a coating film for imparting releasability to the mold surface. According to the present invention, the moldability of the starch container is excellent and the defect rate is small. Furthermore, the starch container formed after molding can be easily separated from the mold.

Starch container, foam, molding, upper mold, lower mold, vent hole, release force, coating film

Description

Starch container forming apparatus and starch container molding method using a mold having a vent hole {Apparatus and method to form starch bowl using mold having vent hole}

1 is a schematic view showing a conventional mold.

2A is a schematic diagram illustrating a mold according to an embodiment of the present invention.

FIG. 2B is an enlarged schematic view of a mold of the container lip portion of the mold of FIG. 2A. FIG.

Figure 3 is a schematic diagram showing a state in which the gas and the foamed surplus for the starch container is discharged through the vent hole when molding the composition for the starch container using a mold according to an embodiment of the present invention.

4 is a schematic cross-sectional view showing a state in which a coating film is formed to impart a release force to the inside of the mold of FIG. 2.

* Description of Major Reference Marks *

10 mold 20 upper mold

30: lower mold 31: contact portion of the lower mold with the upper mold

35 vent hole 36 vent hole exit surface area

37: Inside the lower mold 38: Mold surface area of the container lip

39: coating film 40: molded starch container

50: foamed surplus for starch container discharged

The present invention relates to a starch container forming apparatus and a starch container forming method using a mold having a vent hole, and more particularly, to forming a starch container by foaming the composition for starch container evenly with a vent hole in the mold. The present invention relates to a starch container forming apparatus and a starch container forming method which improves the properties, reduces the defective rate, and further increases the release property by forming a coating film on the mold surface.

In the present invention, the "foamed surplus for starch container" refers to a composition for starch containers remaining without being molded into a container in the process of forming the starch container composition when foamed to form a container that is a molded finished product.

In the present invention, the "mold of the container lip part" is a portion in which the upper mold and the lower mold contact each other, and are formed on the upper mold side, formed on the lower mold side, or formed on the upper mold side and the lower mold side. Means a mold portion for forming a lip of the container.

The starch container is prepared by injecting a starch container composition into a mold and then heating and molding.

1 is a schematic view showing a conventional mold. As shown in FIG. 1, the starch container forming mold 1 generally consists of an upper mold 2 and a lower mold 3, wherein the upper mold 2 moves up and down and the lower mold 3 is fixed. It is.

Then, the starch container composition is introduced into the lower mold 3, and then the upper mold 2 is brought into close contact with the lower mold 3 and heated under pressure to prepare a starch container having a predetermined shape.

In the molding process, the starch container composition is foamed, and when foaming, gas such as water vapor is generated. In addition, most of the composition for starch containers is molded into a container during heating and press molding of the starch container, but some of the foamed surplus for the starch container remains without being molded into the container.

In order to secure moldability and reduce the defective rate, the foamed surplus for gas and starch container should be discharged to the outside of the mold. However, in the conventional mold, the foamed surplus for starch container that is not molded into the gas and container cannot be discharged to the outside of the mold. There is a problem that the pressure is increased under the over-explosion or burst without having the shape of the container.

On the other hand, starch vessels are poor in releasability, resulting in low production efficiency. In other words, the starch container does not easily fall out of the mold after molding, and thus, the inconvenience of having to remove the container from the mold by manual operation after stopping the process results in a decrease in production efficiency. Furthermore, there is a problem that a product defect occurs in the process of removing the container from the mold.

Accordingly, the present invention is to solve the above problems, an object of the present invention is to provide a starch container forming apparatus and a starch container forming method excellent in formability, uniformly foamed, and less defective product.

It is also an object of the present invention to provide a starch container forming apparatus and a starch container forming method that can effectively secure the release property in the starch container forming process.

The present invention for achieving the above object, in the starch container forming apparatus, comprising a starch container forming mold consisting of a top mold and a fixed bottom mold to move up and down, and occurs during the heat press molding of the composition for starch container The vent hole for discharging the foamed surplus for gas or starch container is characterized in that provided in any one or both of the upper mold and the lower mold.

The molding apparatus may be provided with the vent hole in any one or two of the upper mold side contact portion and the lower mold side contact portion among the portions in which the upper mold and the lower mold contact each other.

In the forming apparatus, the ratio of the exit surface area of the vent hole to the mold surface area of the container lip portion in which the vent hole is formed is preferably 1 to 2%.

And, when the mold surface area of the bowl lip part 1400mm ² days, the total of the vent hole outlet surface area is 18 ~ 24mm ² which is preferably, a vent hole 18 to 24 dogs of the vent hole outlet surface area of 1mm ² of the same shape More preferably.

In addition, the molding apparatus is preferably formed with a coating film for imparting releasability to the mold surface, the coating film is more preferably an organic-inorganic composite coating film.

The present invention for achieving the object of the present invention as described above, in the starch container molding method, characterized in that the gas generated during the molding of the starch container composition or the foamed surplus for starch container is discharged during the molding process.

In addition, the molding method preferably forms a vent hole for discharging the gas or the foamed surplus for the starch container in the molding mold itself of the composition for the starch container.

The molding method includes an upper mold and a lower mold fixed to the upper mold and the lower mold, and any one or two of the upper mold side contact portion and the lower mold side contact portion of the upper mold and the lower mold contact. It is preferable to form the vent hole in the.

And, in the forming method, in order to control the discharge of the foamed surplus for the gas or starch container, it is preferable to adjust the ratio of the total sum of the exit surface area of the vent hole to the surface area of the mold of the container lip portion in which the vent hole is formed. The adjustment of the sum of the outlet surface areas of the vent holes is preferably performed by making the outlet surface area of each vent hole the same and adjusting the number of the vent holes.

In the forming method, it is preferable to form a coating film to impart releasability to the mold surface, and more preferably, to form an organic-inorganic composite coating film with the coating film.

Hereinafter, the starch container forming apparatus and the starch container forming method using the mold having the vent hole of the present invention will be described in detail.

Figure 2a is a schematic diagram showing a mold according to an embodiment of the present invention, Figure 2b is a schematic diagram showing an enlarged mold of the container lip portion of the mold of Figure 2a.

As shown in Figure 2a, the starch container forming mold 10 according to an embodiment of the present invention is composed of an upper mold 20 and a fixed lower mold 30 to move up and down, the lower mold 30 The vent hole 35 is formed in the contact portion 31 in contact with the upper mold 20 to discharge gas or foamed surplus for the starch container.

2 shows only that the vent hole 35 is formed in the contact portion 31 of the lower mold, any one or both of the upper mold 20 and the lower mold 30 (preferably the upper mold and the lower mold) Vent holes may be formed in the contacting portion) to control the discharge of the gas or the foamed surplus for the starch container.

In addition, the shape of the vent hole 31 is not limited to the shape as shown in FIG. 2, and the overall shape and the exit surface of the vent hole 31 may be various shapes such as triangular, circular, and trapezoidal. .

In the forming apparatus and method for starch containers of the present invention, it is particularly preferable to control the total outlet surface area of the vent hole. That is, the outlet surface area 36 of the vent hole with respect to the mold surface area 38 of the container lip portion in which the vent hole is formed, as shown in FIG. 2B, in order to secure good formability and uniform foaming, reduce product defect rate, and ensure good workability. It is desirable to adjust the sum of

At this time, the ratio of the exit surface area 36 of the vent hole to the mold surface area 38 of the container lip portion in which the vent hole is formed is preferably 1 to 2%, and when less than 1%, sufficient foaming may not be performed. Increasing the internal pressure can cause explosion or failure rate due to molding failure. When it exceeds 2%, the moldability and the uniformity of the foaming cell may be lowered, and the drying time may increase, resulting in poor workability.

Furthermore, when adjusting the sum of the outlet surface area 36 of the vent hole with respect to the mold surface area 38 of the container lip portion, a plurality of vent holes having the same outlet surface area may be formed, but the number of the vent holes may be adjusted to facilitate uniform foaming. It is preferable because it can be achieved easily.

The ratio of the exit surface area 36 of the vent hole to the mold surface area 38 of such a container lip can be set as follows, for example. That is, the mold surface 38 of the bowl lip part to set the area ratio when the sum total of when 1400mm ^2, the surface area of vent hole outlet 36 to the 18 ~ 24mm ² to within about 1-2% range. At this time, as described above, it is preferable to form 18 to 24 vent holes having the same shape having the exit surface area 36 of the vent hole 1 mm ² , so that uniform foaming and pressure resistance can be controlled.

Figure 3 is a schematic diagram showing a state in which the forming gas or starch container foam surplus discharged through the vent hole when molding the composition for the starch container using a mold according to an embodiment of the present invention.

As shown in FIG. 3, a process of forming a container 40 having a predetermined shape by injecting a starch container composition into the lower mold 30 having the vent hole 35 formed in the contact part 31 and heating and pressing the composition is performed. Gas (not shown) generated during foaming or the foamed surplus for starch container 50 is discharged through the plurality of vent holes 35.

As described above, in the present invention, when the starch container is formed, a vent hole is provided in the mold to control the discharge of the generated gas or the foamed surplus for the starch container, and thus the moldability is good and the product defect rate can be reduced.

On the other hand, the present invention forms a coating film for imparting a release force on the mold surface so that the starch container can be easily separated from the mold.

4 is a schematic cross-sectional view illustrating a coating film formed on an inner surface of the lower mold of FIG. 2.

As shown in FIG. 4, in the present invention, the coating film 39 is formed in the interior 37 of the lower mold 30 having the vent hole 35. 4 illustrates only an inner surface of the lower mold 30 as an example, but a coating film may be formed on the upper mold surface, and a coating film may be formed on both the lower mold and the upper mold surface.

Such coatings facilitate the separation between the mold and the molded container. Furthermore, when the coating film is formed, the surface tension is lowered, and thus, when the heat press molding is performed inside the mold, the starch container composition has a good flowability in the coated mold, so that the container has excellent moldability.

Formation of the coating film is performed by, for example, coating Teflon (organic material coating), forming an oxide film (organic material coating), or forming an organic-inorganic composite coating film.

The Teflon (trade name of Dupont Fluorocarbon Resin) forms a very stable compound by a strong chemical bond of fluorine and carbon to realize excellent chemical inertness, heat resistance, non-tackiness, insulation stability, low coefficient of friction and the like. In coating, Teflon is coated to spray-coated the inner surface of the mold, and then heated and baked at a constant temperature to form a hard coating film.

Anodizing is generally referred to as anodizing, which conducts electricity in the mold to generate oxygen, which causes the surface of the mold to oxidize to form a coating. This film has high strength, high corrosion resistance and very little porosity, so it can be dyed in various colors.

The organic-inorganic composite coating film combines a coating method with an organic material coating and an inorganic material.

For example, fluorine resin (fluorocarbon resin), siloxane resin, and other super engineering plastics which are excellent in lubricity, mold release property, and insulation property; Organic materials such as high-performance plastics suitable for structural and mechanical parts that can be used for a long time even at high temperatures with a tensile strength of 500kgf / cm ² (49MPa) or higher, flexural modulus of 20,000kgf / cm ² (2GPa) or higher, and heat resistance of 150 ° C or higher. It is possible to form an organic-inorganic composite coating film by mixing and coating with an inorganic material such as a metal or a ceramic material, or by applying together with a high hardness inorganic film such as a chemical coating film.

The organic-inorganic composite coating film provides the lubricity, non-adhesiveness, corrosion resistance, oil resistance, and water resistance under conditions requiring high wear resistance and heat resistance, which are not obtained only by conventional organic coatings or inorganic coatings, thereby forming a coating film in the upper and lower molds of the present invention. It is particularly effective at.

Hereinafter, the present invention will be described in more detail by explaining preferred examples and experimental examples of the present invention. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only ordinary in the art while making the present disclosure complete. It is intended to facilitate the implementation of the invention to those with knowledge.

[Experimental Example 1-Evaluation experiment such as release force when forming coating film in mold]

A starch container composition mixed with starch, pulp, water and a conventional additive was molded in a prepared mold having a temperature of 180 ° C. and a pressure of 3 kgf / cm ² for 130 seconds to prepare a molded article having a container shape.

Teflon coating (Example 1 of this Experimental Example 1), oxide film formation (Example 2 of this Experimental Example 1), organic-inorganic composite coating film formation ("BICOAT")-Yoshida SKT Japan (Example 3 of this Experimental Example 1) was used, and 100 molded bodies were prepared in each mold.

In order to measure the release force in each of the embodiments of the present experimental example, when the starch container composition was molded for 130 seconds in the mold, the starch container was not dropped while the container and the upper mold were separated while the upper mold was separated from the fixed lower mold. Sticking to the mold was observed to rise.

In addition, it was observed whether or not pinholes occurred in the container manufactured in each example of the present experimental example. In order to observe the accurate pinhole phenomenon, a tear test was performed by laminating a film having a thickness of 180 μm on a manufactured container.

The leakage test was performed by placing the test solution inside the container, leaving it at room temperature for 20 minutes, and then visually discriminating whether a red liquid flowed out of the container. The test solution was prepared by mixing red ink, surfactant, and water. The leakage of red liquid on the outside of the white or pale yellow vessel made it easy to determine whether or not it was leaking.

Table 1 shows the test results of preparing 100 pieces of starch container compositions in the molds coated with the coating method in the Examples of the present experimental example.

Here, the upper mold attaching refers to a case in which the upper mold is separated from the lower mold fixed immediately after the foaming of the starch container composition, and thus the container is not stuck to the upper mold so that the container is removed from the upper using a human hand or a tool.

In addition, the pinhole phenomenon occurs in the vacuum pressure of 0.1Mpa, vacuum time 1.5 seconds, when laminating a film having a thickness of 180㎛ heated to 130 ℃ in the manufactured container a hole in the laminated surface occurs It shows.

    Molding mold coating material test method Example 1 of the present Experiment 1 Example 2 of Experimental Example 1 Example 3 of Experimental Example 1 The number of containers attached to the upper mold immediately after molding 6 36 0 Number of formed containers of pinhole 5 Nine 0

As can be seen from Table 1, the difference in the moldability of the container according to the molding mold coating material and the difference in the release force between the manufactured container and the mold can be seen.

First, the method of Example 2 to form the oxide film was found that the mold release phenomenon with the starch container is weak, the upper mold sticking phenomenon is apparent a lot, the surface of the prepared container after foaming is not smooth and pin hole phenomenon It was also seen by the naked eye that this occurred.

In addition, the method of Example 1 coated with Teflon showed a similar release force as in Example 3, but several experiments showed the phenomenon that the Teflon coating peeled off from the mold.

Therefore, it was found that the molding mold coating in forming the starch container composition is most preferably in the case of forming the organic-inorganic composite coating film of Example 3.

Experimental Example 2 Experiments on Differences in Formability According to Area and Number of Vent Holes

In this experiment, was fixed to a mold surface of the lower bowl lip portion that the vent hole formed in a 1400mm ^2, respectively carried out by varying the vent hole size and number of cases (if the sum of the vent hole outlet surface area of 18 ~ 24mm ²⁾ and Comparative Example The bottom mold (when no vent hole was formed and the sum of the vent hole exit surface areas is outside the range of the above embodiment) was produced. Each star mold was used to foam 100 starch container moldings, and then a starch container was completed.

<Example 1 of this Experimental Example 2>

The starch container composition prepared by mixing starch, pulp, water and conventional additives is placed in a heated press lower mold heated at 180 ° C., covered with an upper mold, and molded at 3 kgf / cm ² for 130 seconds to foam 100 starch. The container was prepared.

In the lower mold, a vent hole was formed at the upper edge portion, which is a contact portion of the lower mold, of the portion where the upper mold and the lower mold contacted, and serves as a discharge of the foamed surplus for the starch container, which is not formed of gas and a container.

The outlet surface areas of the vent holes were equally 1 mm (width) x 1 mm (height), and a lower mold having 18 vent holes of the same shape and size was manufactured to foam the composition for starch containers. On the other hand, the upper and lower molds were coated with an organic-inorganic composite coating "BICOAT" (manufactured by Yoshida SKT Co., Ltd.) to form an organic-inorganic composite coating film.

<Example 2 of this Experimental Example 2>

The outlet surface areas of the vent holes were all 1 mm (width) x 1 mm (height) in the same manner, and a lower mold was formed in which 24 vent holes of the same shape and size were formed to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 1 of Experimental Example 2

A lower mold having no vent holes was prepared to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 2 of Experimental Example 2

The exit surface areas of the vent holes were all the same 1 mm (width) x 1 mm (height), and a lower mold was formed in which twelve vent holes of the same shape and size were formed to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 3 of Experimental Example 2

The outlet surface areas of the vent holes were all 1 mm (width) x 1 mm (height) in the same manner, and a lower mold was formed in which 30 vent holes of the same shape and size were formed to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 4 of Experimental Example 2

The exit surface areas of the vent holes were all 0.5 mm (width) x 1 mm (height) in the same manner, and a lower mold was formed in which 18 vent holes of the same shape and size were formed to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 5 of Experimental Example 2

The outlet surface areas of the vent holes were all 3 mm (width) x 1 mm (height) in the same manner, and a lower mold was formed in which 18 vent holes of the same shape and size were formed to foam the starch container composition. The rest was carried out in the same manner as in Example 1.

Comparative Example 6 of Experimental Example 2

The exit surface areas of the vent holes were 5 mm (width) x 1 mm (height) in the same manner, and a lower mold was formed in which 18 vent holes of the same shape and size were formed to foam the composition for starch containers. The rest was carried out in the same manner as in Example 1.

Table 2 summarizes the size and number of the vent holes of Examples 1 and 2 and Comparative Examples 1 to 6 of the present Experimental Example 2.

Vent width (width) x (height) Count Example 1 of this Experimental Example 2 1mm × 1mm 18 Example 2 of Experimental Example 2 1mm × 1mm 24 Comparative Example 1 of the Experimental Example 2 - 0 Comparative Example 2 of the Experimental Example 2 1mm × 1mm 12 Comparative Example 3 of the Experimental Example 2 1mm × 1mm 30 Comparative Example 4 of the Experimental Example 2 0.5mm × 1mm 18 Comparative Example 5 of the Experimental Example 2 3mm × 1mm 18 Comparative Example 6 of the Experimental Example 2 5 mm x 1 mm 18

In this experiment, moldability, foam cell uniformity, defective rate, and drying time in Examples 1 and 2 and Comparative Examples 1 to 6 were measured.

Moldability of the Container

◎ indicates that the surface is smooth and there are no wrinkles or pinholes, O indicates that the surface is relatively rough, but there are no wrinkles or pinholes, and X indicates that the surface has wrinkles or pinholes or is difficult to form and cannot be used as a product. Indicates degree.

Foam Cell Uniformity

The foamed starch vessel was cut with a sharp knife and observed with an electron microscope to analyze whether the foamed cells were formed uniformly. In the measurement result, "uniform" means that the size of the foam cell is formed uniformly and uniformly. "Non-uniform" means that the size of the foam cell is formed non-uniformly.

Defective rate

100 starch containers made from each mold were inspected for defects. As used herein, the term "defect" means that the container is torn, wavy, wrinkled, over-foamed, a large amount of pinholes and an explosion due to an increase in internal pressure.

Drying time

When a constant temperature (180 ° C.) and a constant pressure (3 kgf / cm ² ) were applied, the time required for forming the starch container composition in the mold was measured.

Table 3 shows the measurement results of the moldability, foam cell uniformity, defective rate, and drying time.

Container formability Foam Cell Uniformity Defective rate Drying time Example 1 of this Experimental Example 2 ◎ Uniformity 0% 130 seconds Example 2 of Experimental Example 2 ◎ Uniformity 0% 130 seconds Comparative Example 1 of the Experimental Example 2 X Heterogeneity 100% - Comparative Example 2 of the Experimental Example 2 O Heterogeneity 61% 125 seconds Comparative Example 3 of the Experimental Example 2 X Heterogeneity 43% 150 sec Comparative Example 4 of the Experimental Example 2 O Heterogeneity 64% 125 seconds Comparative Example 5 of the Experimental Example 2 X Heterogeneity 57% 150 sec Comparative Example 6 of the Experimental Example 2 X Heterogeneity 77% 150 sec

As can be seen from Table 2 and Table 3, when the mold surface area of the lower container lip portion is 1400mm ² , the number of vent holes formed in the lip portion is 18-24, and the same area of each vent hole is 1mm ² . It was found that the moldability was excellent, the foaming cell was uniform, and the defect rate was small.

On the other hand, as the vent hole size decreases, not only the moldability of the container is excellent, but also the foaming rate is excellent due to an increase in the internal pressure within the mold.

On the other hand, when the ratio of the exit surface area of the vent hole to the mold surface area of the container lip portion is not 1% as in Comparative Examples 2 and 4, the internal pressure increases and an explosion rate occurs or the defective rate due to molding failure is high. I could confirm that.

In addition, when the mold is not provided with any vent holes (Comparative Example 1 of this Experimental Example 2), the gas to be escaped from the mold or the foamed surplus for the starch container is not discharged, and the composition for the starch container is over-foamed or It can be seen that due to the excessive rise in the internal pressure, the container does not form and bursts.

In addition, as the number of the vent holes increases to 25 or more (Comparative Example 3 of this Experimental Example 2) or as the area of the vent holes increases (Comparative Examples 5 and 6 of this Experimental Example 2), the inside of the mold becomes a low pressure state and the starch container It was found that the composition was undried and the drying time was increased, resulting in poor workability (increased to 150 seconds).

Accordingly, when the mold surface of the lower bowl lip part in the case of 1400mm ^2, the same area of 1mm ² in a vent hole number is 18 to 24 pieces, or the total area of the vent holes is 18 ~ 24mm ^2, that is, lip container portion In the case where the ratio of the total area of the vent hole to the mold surface area of about 1 to 2% was less, it was found that the defect was less, and the moldability and the bubble layer formation were excellent.

According to the present invention, the moldability of the starch container is excellent and the defect rate is low, and further, after forming, the formed starch container can be easily separated from the mold.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (14)

In the starch container forming apparatus, It comprises a starch container forming mold consisting of an upper mold and a fixed lower mold to move up and down, A vent hole for discharging the gas generated during the heating and press molding of the starch container composition or the foamed surplus for the starch container is formed in the lip portion of the container mold. The starch container forming apparatus, characterized in that the ratio of the total of the outlet surface area of the vent hole to the mold surface area of the container lip portion in which the vent hole is formed is adjusted to 1-2%. delete delete The method of claim 1, wherein the molding apparatus, When the mold surface area of the container lip portion is 1400mm ² , the starch container forming apparatus, characterized in that the total of the outlet surface area of the vent hole is 18 ~ 24mm ² . The method of claim 4, wherein the molding apparatus, The starch container forming apparatus, characterized in that 18 to 24 vent holes of the same shape having an outlet surface area of the vent hole is 1mm ² is formed. The said shaping | molding apparatus in any one of Claim 1, 4 or 5, A starch container forming apparatus, wherein a coating film is provided on the upper mold, the lower mold, or the upper mold and the lower mold surface. The method of claim 6, wherein the molding apparatus, Starch container molding apparatus, characterized in that the coating film is an organic-inorganic composite coating film. In the starch container molding method, The gas generated during the molding of the starch container composition or the foamed surplus for the starch container is formed in the container lip of the starch container forming mold including the upper mold and the fixed lower mold which move up and down the vent hole discharged during the molding process. The method of forming a starch container, characterized in that the ratio of the sum of the outlet surface area of the vent hole to the mold surface area of the container lip portion in which the vent hole is formed is adjusted to 1 to 2%. delete delete delete The method of claim 8, wherein the molding method, The method of forming a starch container, characterized in that the outlet surface area of each vent hole is the same and the number of vent holes is adjusted when adjusting the sum of the outlet surface areas of the vent holes. The method according to claim 8 or 12, wherein the molding method, A method of forming a starch container, characterized in that to form a coating film to impart releasability to the upper mold, the lower mold, or the upper mold and the lower mold surface. The method of claim 13, wherein the molding method, The coating film is a starch container molding method, characterized in that to form an organic-inorganic composite coating film.

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