KR100811189B1 - Heat resistant container manufacture method - Google Patents

Abstract

A method for preparing a biodegradable container is provided to improve heat resistance and to prevent the deformation of a container during the package and delivery of food. A method for preparing a biodegradable container comprises the steps of (ST1) pasting a starch mixture comprising at least one starch powder selected from sweet potato, potato, corn, rice, wheat and sugar cane; (ST2) molding the paste to a shape of sheet; (ST3) preheating the molded sheet at a temperature of 40-130 deg.C; (ST4) vacuum molding the sheet by using a mold having the shape of a container; and (ST6) heating the molded container in a vacuum chamber at a temperature of 90-110 deg.C to increase heat resistance.

Description

Heat Resistant Biodegradable Container Manufacturing Method {HEAT RESISTANT CONTAINER MANUFACTURE METHOD}

1 is a manufacturing method flow chart of the present invention.

Figure 2 is an external view of the container produced by the present invention.

The present invention relates to a biodegradable container manufacturing method, and more particularly to a manufacturing method for further strengthening the heat resistance characteristics of the biodegradable container is an environmentally friendly synthetic resin.

In general, typical disposable products that are used and discarded once include lunch box containers, cup noodles containers, and buffers. Most of these products are made of plastic, styrofoam, paper, synthetic resin, etc., so they are easily used and easily discarded.

However, these abandoned plastics, styrofoam, synthetic resins have a problem of saturation of the landfill because it takes about 500 years to disassemble when landfilled.

In order to solve these environmental problems, development of biodegradable plastics (PLA) using corn starch has been in the spotlight.

However, the conventional biodegradable plastic container has a weak disadvantage in durability and heat, there was a problem that the deformation easily occurs due to the weight of the contents when used as a food storage container.

The present invention has been proposed to improve the above problems in the prior art, to propose a manufacturing method that can enhance the durability and heat resistance of the biodegradable plastic container to maximize the ease of use and reliability of the product when used for food packaging The purpose is to.

The object is a dough step of kneading the starch mixture containing at least one starch powder selected from sweet potatoes, potatoes, corn, rice, flour, sugar cane; A sheet forming step of molding the mixture made of the dough into a sheet form; A preheating step of preheating the molded molding sheet to a high temperature; A container molding step of performing vacuum molding of the molding sheet using a mold having a predetermined container shape; A heating step of heating the molded container in a vacuum chamber; It is possible to achieve through the heat-resistant enhanced biodegradable container manufacturing method comprising a.

Hereinafter, looking at the manufacturing process of the biodegradable PLA container according to a specific embodiment of the present invention with reference to the flow chart of FIG.

<Starch mixture dough step> ( ST  One)

First, the starch used in the kneading step of the mixture is extracted from one or more crops selected from sweet potatoes, potatoes, corn, rice, flour, and sugar cane. The starch powder is 80% by weight of sorbitol 10% by weight, and the heat-resistant reinforcement 10 The weight percent is mixed and stirred to knead.

In other words, the container made of starch only has a heat deformation temperature of 50 ° C., which is weak to heat, thereby adding a heat-resistant reinforcing agent to reinforce the heat-resistant temperature up to about 70-80 ° C. In this case, the heat-resistant reinforcement used is a powder form that is harmless to the human body. Silicon nitride is used, and it is preferable to maximize the heat strengthening resistance by selectively adding aluminum oxide or radioisotope yttrium (90-Yttrium) in a ratio of 6: 4 to silicon nitride by weight.

In particular, the yttrium is mainly used as a sintering accelerator, and when added to the mixture, it serves to increase the bonding force between the silicon powder and the starch particles.

<Sheet forming step> ( ST  2)

On the other hand, the mixture is made of the dough is extruded in the form of a fillet is molded in a sheet form, in this sheet forming step it is possible to form into a thin sheet form by inserting the extrusion molding to the roller.

Then, the molded sheet is wound in a roll form in a winder and moved to the next step.

<Sheet preheating stage> ( ST  3)

In this preheating step, the temperature is gradually increased from the mild heat in order to enhance the heat resistance of the formed sheet to about 100 ℃.

That is, in this case, preheating is performed in three stages to strengthen the heat resistance. First, the preheating process of preheating the molding sheet at a temperature of 50 ° C. for 30 seconds (ST 3-1), and the first preheating is performed. Secondly preheating the sheet again for 30 seconds at a higher temperature of 80 ° C (ST 3-2) and preheating the formed sheet with secondary preheating for 30 seconds at a temperature of 120 ° C. The third preheating process (ST 3-3) is performed sequentially.

In particular, the first preheating process (ST 3-1) of the preheating temperature in each process to satisfy the temperature range of 40 ~ 60 ℃, in the second preheating process (ST 3-2) the preheating temperature is 70 ~ It is desirable to satisfy the range of 90 ℃, and in the third preheating process (ST 3-3) it is preferable to satisfy the preheating temperature range of 110 ~ 130 ℃.

If it is out of the temperature range of each process, it can be seen through the experimental example of the following [Table 1] that the problem that the heat-resistant temperature reinforcement up to the desired temperature value can not occur.

division Primary preheat temperature Second preheat temperature 3rd preheat temperature Heat-resistant temperature Experimental Example 1 (invention) 50 80 120 100 Experimental Example 2 (Invention) 45 78 112 99 Comparative Example 1 55 65 90 82 Comparative Example 2 70 80 90 79 Comparative Example 3 50 100 150 Defect

As can be seen through the above experimental example Experimental Examples 1 and 2, which were preheated in three stages within the temperature range of the present invention, the heat resistance temperature of the sheet itself showed satisfactory results of 100 ℃ and 99 ℃, Comparative Examples 1,2 In the case of, 3, the heat resistance temperature was low, making it difficult to manufacture as a container. In particular, in the case of Comparative Example 3, the third preheating temperature was too high, so that the soot occurred partially in the sheet.

In addition, the preheating time in each process is also preferably to be carried out within the range of 25 ~ 35 seconds.

Through these three preheating steps, the temperature that can withstand thermal deformation of the final molded container can be compensated up to about 100 ° C.

<Container Forming Step> ( ST  4)

On the other hand, in the container forming step, the sheet subjected to the preheating process is molded in a mold by a pressure vacuum method, thereby forming a container.

At this time, it is appropriate to carry out within 10 seconds by maintaining the air pressure of 7kgt / cm2, the cooling water temperature is maintained in 40 ℃ after slowly cooling for 30 seconds to form a container.

On the other hand, it is preferable to maintain the surface temperature of the sheet before molding within the range of 110 ~ 120 ℃.

<Cooling stage> ( ST  5)

The molded container is cured through a cooling process, and the cooling is performed for 30 seconds while maintaining a mold temperature of about 70 ° C.

At this time, the mold temperature is preferably in the range of 20 to 40 seconds cooling time while satisfying the 65 to 75 ℃ range.

<Heating stage> ( ST  6)

On the other hand, the container is cooled and cured to maximize the heat resistance by performing the final heating process in the heater chamber forming the internal vacuum state.

That is, in this case, heating is performed at 100 ° C. for 2 minutes to raise the heat resistance temperature to about 120 ° C., at which time the heating temperature is performed at a temperature range of 90 to 110 ° C., and the heating time is maintained at 2 to 3 minutes. This is desirable.

Table 2 shows the heat resistance temperature of the container according to various set temperatures in the present heating step as an experimental example.

division Heating temperature (℃) Heat resistance temperature (℃) Experimental Example 1 (Invention) 100 120 Experimental Example 2 (Invention) 110 122 Comparative Example 1 80 105 Comparative Example 2 125 Poor (container deformation)

As can be seen through the experimental example, in the case of Experimental Examples 1 and 2 carried out in the temperature range of the present invention, the heat resistance temperature to withstand the thermal deformation of the container showed 120 ℃ or more, in the case of Comparative Examples 1 and 2 Was rapidly lowered, or it could be confirmed that a defect occurred due to the deformation of the container.

In addition, when the heating time is 2 minutes or less, the heat resistance complementary effect is insignificant, and when the heating time is 3 minutes or more, the effect of increasing the heat resistance temperature no longer appears.

Figure 2 shows the appearance of the PLA container according to the embodiment of the present invention, the production is completed, the biodegradable PLA container made through each step of the present invention is mainly used for food packaging.

In particular, the biodegradable container of the present invention is enhanced in the heat resistance characteristics can be prevented from occurring deformation such as sag of one side of the container even if the packaging containing a high temperature food weight.

That is, since the freshly cooked food in a meat manufacturing plant such as chicken has a certain temperature, the conventional biodegradable container has a deformation of the container due to the influence of food temperature and weight, but the heat resistance of the present invention is enhanced. When the food is packaged in a packaged PLA container, the shape of the entire container can be maintained as it is, and thus, problems due to the bottle shape of the container can be improved.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the process of manufacturing the container of the present invention may be variously modified and implemented by those skilled in the art.

However, such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments shall fall within the appended claims of the present invention.

The present invention as described above has the effect of preventing the deformation of the container from the packaging of the meat food to be packaged to transport and sale by improving the heat resistance of the biodegradable starch container used for food packaging.

In particular, by adding a heat-resistant reinforcing material in the material kneading process for manufacturing the container, the heat resistance temperature is increased to 70 ~ 80 ℃, and after the three stages of preheating process to increase the heat resistance temperature to 100 ℃, the final heating step after forming the container Through this, it is possible to maximize the heat resistance temperature to withstand heat deformation up to 120 ℃.

Claims (7)

Kneading step of kneading the starch mixture containing at least one starch powder selected from sweet potatoes, potatoes, corn, rice, flour, sugar cane; (ST 1) Sheet molding step of molding the mixture made of the dough into a sheet form; (ST 2) Preheating step of preheating the molded molding sheet to 40 ~ 130 ℃; (ST 3) Container molding step of performing a vacuum molding of the molded sheet using a mold of a predetermined container form; (ST 4) Heating step of heating to a temperature of 90 ~ 110 ℃ in a vacuum chamber to enhance the heat resistance of the completed container; (ST 6) Heat-resistant enhanced biodegradable container manufacturing method comprising a. The method according to claim 1, In the preheating step (ST 3), the first pre-heating process of preheating the molded sheet at a temperature of 40 ~ 60 ℃; (ST 3-1) A second preheating process of preheating the molded sheet having the first preheating at a temperature of 70 to 90 ° C .; (ST 3-2) Heat-resistant enhanced biodegradable container manufacturing method characterized in that the third pre-heating process (ST 3-3) to perform the pre-heating again the second formed pre-formed sheet at a temperature of 110 ~ 130 ℃. The method according to claim 2, In each preheating process, the preheating is carried out for 25 to 35 seconds, characterized in that the heat-resistant enhanced biodegradable container manufacturing method. The method according to claim 1, After the container forming step (ST 4) to produce a heat-resistant biodegradable container characterized in that the cooling step (ST 5) to perform the cooling for 20 to 40 seconds while maintaining the mold temperature at 65 ~ 75 ℃ Way. The method according to any one of claims 1 to 4, In the heating step (ST 6), the molded container is put in a vacuum chamber of the heater and heated for 2 to 3 minutes to cure the molding container, characterized in that the heat-resistant enhanced biodegradable container manufacturing method. The method according to claim 1, The kneading step (ST 1) is a heat-resistant enhanced biodegradable container manufacturing method characterized in that the silicon nitride in the form of powder is further added as a heat-resistant reinforcing agent. The method according to claim 1 or 6, In the kneading step (ST 1), a heat-resistant enhanced biodegradable container manufacturing method, characterized in that the addition of yttrium, which is aluminum oxide or radioactive isotope with silicon nitride as a heat-resistant reinforcing agent.

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