WO2007073039A1

WO2007073039A1 - Natural binder for binding natural powder and manufacturing method thereof

Info

Publication number: WO2007073039A1
Application number: PCT/KR2006/004793
Authority: WO
Inventors: Yong-Duk Kwon
Original assignee: Sajaco Co., Ltd.
Priority date: 2005-12-19
Filing date: 2006-11-15
Publication date: 2007-06-28
Also published as: KR100624914B1

Abstract

Disclosed are a natural binder for binding natural powder and a manufacturing method thereof, and more particularly, a natural binder able to strongly bind natural powder, which is environmentally friendly, and a manufacturing method thereof. According to the invention, the natural binder, including 45-56 wt% of natural carboxymethyl cellulose starch, 9-14 wt% of natural shellac, 8-13 wt% of natural casein, 20-28 wt% of natural sorbitan ester starch, 0.5-2 wt% of natural cou malong, and 0.5-2 wt% of natural stearic acid, is provided, along with the method of manufacturing the natural binder.

Description

NATURAL BINDER FOR BINDING NATURAL POWDER AND MANUFACTURING METHOD THEREOF

Technical Field

[1] The present invention relates to a natural binder for binding natural powder and a manufacturing method thereof, and more particularly, to a natural binder, having increased ability to bind natural materials, thus simplifying the process of producing a disposable container, and to a method of manufacturing the same. Background Art

[2] With the complication and diversification of peoples' living culture according to the development of the industrial economy, disposable containers for saving time have been usefully produced in various shapes. Examples of such containers include disposable goods, such as spoons, cups, dishes, lunch boxes, etc.

[3] The material for such disposable containers is composed mainly of synthetic resin

(polystyrene) or pulp.

[4] However, although synthetic resin products contain components harmful to human bodies, they are used more and more, and are regarded as a primary cause of undesirable environmental pollution due to post-treatment problems therewith, and consequently limitations are imposed on the use thereof.

[5] Further, paper products made from pulp also have disadvantages, such as economic problems related to the fact that most of the pulp used is imported, environmental deterioration problems due to the cutting of wood materials required for the production of pulp, and environmental pollution problems resulting from the use of additives supplied in the course of pulp production.

[6] Alternatively, in place thereof, recycled pulp may be used. However, attributable to the treatment with, and disposal of, additives used in various recycling procedures and energy required to recycle pulp, secondary environmental pollution problems arise. Further, in order to alleviate structural problem with the pulp material, the surface of the pulp is subjected to waterproof coating using vinyl, which is considered to be a major source of environmental pollution. Hence, under the variety of environmental rules, the use of vinyl products is limited. Moreover, stores that sell such containers must sort and dispose of them, which is inconvenient.

[7] In addition, the reason why the above-mentioned disposable containers are limitedly used is that most conventional disposable containers do not decompose in nature, and thus do not break down when simply buried underground, resulting in soil pollution, and furthermore, environmental pollutants, such as dioxins, are discharged upon in- cineration.

[8] To alleviate the problems, although biodegradable disposable containers have been produced, they entail high production costs and have structural problems which make the actual use thereof impossible.

[9] Specific conventional techniques are described below.

[10] Thorough research into the replacement of polystyrene with natural polymer materials, obtainable from starch of cereals or wheat flour and cereal shells, is being performed these days.

[11] In the case of using cereal flour, exemplary are a method of subjecting a mixed paste of wheat flour, starch, baking powder and edible salt to molding, freezing and coating (Korean Examined Patent Publication No. 96-0006565) and a method of subjecting a mixed paste, comprising starch of cereals and wheat flour, as main ingredients, sugar, a flavoring agent, and yeast, as adjuvant ingredients, along with purified water at an appropriate temperature, to aging, extrusion, molding, and freeze- drying (Korean Unexamined Patent Publication No. 99-0047173).

[12] In the case of using cereal shells, exemplary are a method of subjecting a mixture, comprising milled shells of rice plants, barley, millet and sorghum, water, and starch, to stirring, molding and coating (Korean Patent Application No. 99-0055567), and a method of subjecting a mixture comprising plant particles, obtained by milling corn stalks or soybean hulls, and edible glue, to stirring and compression into a molded article (Korean Patent Application No. 99-0037967).

[13] However, conventional products, made through the above techniques, suffer because they are heavy, are easily broken, and may contract due to external temperatures, and thus undesirably have many limitations in use.

[14] Further, to alleviate such problems, although natural polymers should be mainly used, these inevitably require the use of an indecomposable additive.

[15] Therefore, the disposable containers still have many problems related to decomposition, and are expensive, and are thus difficult to use in practice.

[16] In addition, the problems may be alleviated by the invention disclosed in Korean

Patent Application No. 10-2003-0051418, filed by the present applicant and subsequently approved. Although this invention may exhibit more advantages than those of the conventional techniques, it is disadvantageous because the cereal flour mixture, as one constituent of natural materials, has poor ability to bind to the other constituents. As such, with the intention of reinforcing such binding ability, a boiling process should be conducted as a pretreatment procedure to cause the materials to be glutinous, which is somewhat complicated to prepare. Disclosure of Invention Technical Problem

[17] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a natural binder for strongly binding natural powder, which is environmentally friendly, and a preparation method thereof. Brief Description of the Drawings

[18] FIG. 1 is a schematic view illustrating the apparatus for manufacturing the natural binder of the present invention;

[19] FIG. 2 is a graph illustrating the FT-IR spectra of various compositions for the natural binder of the present invention;

[20] FIG. 3 is a scanning electron micrograph (SEM) illustrating the surface state of the natural binder of the present invention, comprising natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid + natural sorbitan ester, which are mixed and thus dispersed;

[21] FIG. 4 is an SEM illustrating the surface state of a natural binder, comprising natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid, which are mixed and thus dispersed;

[22] FIG. 5 is a graph illustrating the degree of swelling (which is measured using DMF and water at 25⁰C) of the starch phase of the natural binder of the present invention, comprising natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid + natural sorbitan ester;

[23] FIG. 6 is a graph illustrating the degree of swelling (which is measured using DMF and water at 25⁰C) of the starch phase of the natural binder, comprising natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid. Best Mode for Carrying Out the Invention

[24] In order to achieve the above object and eliminate conventional defects, the present invention provides a natural binder, comprising natural carboxymethyl cellulose starch, natural shellac, natural casein, natural sorbitan ester starch, natural cou malong, and natural stearic acid, which are mixed together.

[25] More particularly, the ratio of the components constituting the natural binder of the present invention is set as follows.

[26] The natural binder of the present invention is composed of 45-56 wt% of natural carboxymethyl cellulose starch, 9-14 wt% of natural shellac, 8-13 wt% of natural casein, 20-28 wt% of natural sorbitan ester starch, 0.5-2 wt% of natural cou malong, and 0.5-2 wt% of natural stearic acid.

[27] As such, natural carboxymethyl cellulose powder has sodium glycolate ether groups in a number not more than 0.8 per unit (C ) of cellulose molecule, and is water-soluble

6 cellulose. As fundamental properties, the above component becomes a viscous liquid when dissolved in water, and has antifungal or antidecay properties, thus achieving long storage. This component is used as starch for various fiber products, and is blended with a detergent to increase washing effectiveness, and may be additionally applied to medicine, cosmetics, and the food industry.

[28] The reason why this natural carboxymethyl cellulose is added to the natural binder of the present invention is that it is easily bound with starch, cellulose, and amino acid, and functions to confer viscosity to an emulsion for good flowability at high temperatures and to enable easy extrusion molding.

[29] Also, the amount of the above component that is added is set in the range of 45-56 wt%. This is because the use of less than 45 wt% thereof results in weakened binding ability, a roughened surface, and deformation in a microwave oven, whereas the use thereof exceeding 56 wt% results in poor biodegradability.

[30] Preferably, the carboxymethyl cellulose starch is used in an amount of 50 wt%.

[31] In addition, natural shellac is produced from the secretions of an insect, that is,

Laccifer lacca, deposited on branches of trees in India, and is pale yellow or light brown, and is in various forms of flakes, particles, or powders. The fundamental properties thereof are a melting point of 15O⁰C, a softening point of 95⁰C, a specific gravity of 1.113-1.214, an acid value of 60, a saponification value of 200, and an iodine value of 18. This component is completely dissolved in a solution of alcohol and boric acid, and is partially dissolved in a solution of ether, acetone, and carbon disulfide, but is insoluble in water. Further, the shellac serves as a sealing wax or molding material for varnish, adhesives, electrical insulators, and records.

[32] The reason why such natural shellac is added to the natural binder of the present invention is that it functions to prevent the generation of formaldehyde, which plays a chief role in inducing cancer and causing sick house syndrome, and to improve flowability and eliminate deformation upon molding.

[33] Also, the amount of natural shellac that is added is set in the range of 9-14 wt%.

This is because the use of less than 9 wt% thereof results in poor moldability, whereas the use thereof exceeding 14 wt% results in precipitation in the form of cotton in a reactor.

[34] Preferably natural shellac is used in an amount of 12 wt%.

[35] Furthermore, natural casein is a main constituent of milk, and a lot of research into milk casein has been conducted. Casein from human beings is known to have properties similar to that from sheep. The casein is contained in milk in an amount of about 3% and constitutes about 80% of the total amount of milk protein. When the pH of milk is set at 4.6 through the addition of an acid, casein is precipitated at an isoelectric point, and is therefore easy to formulate. The casein is known to have three ingredients, that is, a-casein (70% of the total amount of casein), b-casein (27%), and g-casein (3%). The chemical composition of casein further includes 1% phosphorous and 1% sugar, in addition to amino acid. Further, a-casein has a molecular weight of 25,000-27,000 and b-casein has a molecular weight of 17,000-20,000, and the two caseins may be efficiently formed into an association. Furthermore, according to pharmacopeia, casein is prescribed to contain 15.2-16.0% nitrogen after being dried at 100⁰C. The casein component is used for a digestion test, massage cream (in the form of an emulsion), and as a source of nutrition. Further, casein is used to make buttons and umbrellas, as well as imitations of ivory, coral, and pearl. Moreover, casein is useful for the preparation of casein fiber (Lanital) and coatings for paint, adhesives, and paper. As such, these applications are based on casein protein, which is producible from milk through isoelectric precipitation.

[36] The reason why such natural casein is added to the natural binder of the present invention is that it has good gelatination and tackiness.

[37] Also, the amount of natural casein that is added is set in the range of 8-13 wt%.

This is because the use of less than 8 wt% thereof results in difficulty in forming a liquid crystal emulsion copolymer of a water-soluble polymer, whereas the use thereof exceeding 13 wt% results in weakened stability and binding ability of the copolymer, undesirably changing the concentration and surface tension.

[38] Preferably natural casein is used in an amount of 11 wt%.

[39] In addition, the reason why natural sorbitan ester starch is added to the natural binder of the present invention is that the emulsion polymer is endowed with hy- drophilicity to thus realize dispersion and stabilization of the emulsion, and also that hydrophobic monomers may be copolymerized to thereby exhibit good water resistance and weather resistance.

[40] Further, the amount of the above component that is added is set in the range of

20-28 wt%. This is because the use of less than 20 wt% thereof results in low water resistance and weather resistance, whereas the use thereof exceeding 28 wt% results in high water resistance and weather resistance, but low biodegradability.

[41] Preferably sorbitan ester starch is used in an amount of 25 wt%.

[42] In addition, natural cou malong is a natural adhesive extracted from the trees of tropical regions or paper mulberry. The reason why such natural cou malong is added to the natural binder of the present invention is that it ensures storage stability and ther- mocompression molding.

[43] Also, the amount of cou malong that is added is set in the range of 0.5-2 wt%. This is because the use of less than 0.5 wt% thereof leads to insufficient adhesive force, whereas the use thereof exceeding 2 wt% leads to limited tensile strength and water resistance, and inability to withstand a temperature of 15O⁰C or more.

[44] Preferably natural cou malong is used in an amount of 1 wt%.

[45] In addition, natural stearic acid, represented by C H O , is in the form of white flaky crystals at room temperature, and has a melting point of 71-71.5⁰C and a solidifying point of 69.4⁰C. This component is insoluble in water but is readily dissolved in an organic solvent. The above component, which is ester with glycerol, is contained in oils and fats or phospholipids of animals or plants and is the natural fatty acid that is present in the greatest amount. The above component is contained in a large amount in solid fat from cows and sheep at room temperature but in a relatively small amount in plant oil in a liquid phase. Soap is prepared via saponification of oil and fat with sodium hydroxide, the main ingredient of which is sodium salt of stearic acid.

[46] The reason why such natural stearic acid is added to the natural binder of the present invention is that flowability is good, and thus thermocompression may be easily controlled.

[47] Also, the amount of the above component that is added is set in the range of 0.5-2 wt%. This is because the use of less than 0.5 wt% thereof results in poor flowability, whereas the use thereof exceeding 2 wt% results in good flowability but also in the generation of bubbles.

[48] Preferably, natural stearic acid is used in an amount of 1 wt%.

[49] FIG. 1 schematically illustrates the apparatus for manufacturing the natural binder of the present invention. As illustrated in this drawing, the apparatus comprises an oil bath having an inlet and an outlet for heating and cooling for temperature control, a reactor having a four-neck flask and provided in the oil bath; and a high-speed stirrer; a nitrogen inlet; a thermometer; and a condenser, provided in respective openings of the four-neck flask of the reactor. According to the present invention, materials for a natural binder are introduced into the four-neck flask of the reactor to thus be subjected to individual preparation process steps. The method of manufacturing the natural binder of the present invention is described in detail below.

[50] The manufacturing method of the present invention comprises preparing the components of the natural binder of the present invention, including 45-56 wt% of natural carboxymethyl cellulose starch, 9-14 wt% of natural shellac, 8-13 wt% of natural casein, 20-28 wt% of natural sorbitan ester starch, 0.5-2 wt% of natural cou malong, and 0.5-2 wt% of natural stearic acid, and then selecting the added amounts of the components according to a predetermined component ratio;

[51] adding the natural carboxymethyl cellulose starch and the natural sorbitan ester starch with the natural stearic acid and the natural cou malong, appropriately selected according to the component ratio, and then introducing nitrogen to thus form an inert atmosphere for condensation at 170- 175⁰C so that dehydration and condensation take place;

[52] adding the shellac to the condensation product, and then stirring the condensate at

120- 125⁰C for 10 hours to thus allow it to react;

[53] cooling the reaction product to 100⁰C or less to age it, therefore stabilizing an emulsion; and

[54] adding the natural casein to the stabilized emulsion, and then stirring the emulsion at 210~235°C for 1 hour or more in a nitrogen-introduced inert atmosphere to thus allow it to react.

[55] Here, the reason why the temperature for the condensation is limited to 170- 175⁰C is that insufficient dehydration occurs at a temperature below the lower limit, whereas excessive dehydration occurs at a temperature above the upper limit, and consequently condensation satisfying the properties of the present invention does not occur.

[56] For condensation, carboxymethyl cellulose starch and sorbitan ester starch may be used in the form of material containing 20-40 wt% moisture based on the total amount of the components. Alternatively, useful is a well-dried starch material having about 35 wt% moisture based on the total amount thereof. Then, when such a material is stirred and heated, a viscous adhesive having good properties may be formed. That is, the product resulting from the condensation has good dispersibility and wettability and becomes a proteolytic biodegradable binder.

[57] In the above process, in order to obtain a condensate, nitrogen is supplied.

[58] The present invention is not patentable by virtue of the moisture content alone, the moisture merely being responsible for efficient stirring. After the preparation of the binder of the present invention, since the moisture is removed, the amount thereof is excluded from the powder component ratio. Further, in the present invention, when a container composition in a powder state, which comprises the natural binder prepared through the method of the present invention, is loaded into a mold and then compressed to induce adhesion, it is possible to mold a container even in the absence of moisture. That is, the present invention is patentable by virtue of the components in a powder phase and the component ratio of a final adhesive.

[59] The reason why the temperature for the process of adding the shellac and performing stirring for 10 hours or more for reaction is limited to 120- 125⁰C is that insufficient reaction takes place at a temperature below the lower limit, whereas excessive reaction occurs at a temperature above the upper limit, and consequently it is difficult to realize the properties required in the present invention.

[60] Further, in the process of stirring for 10 hours or more, in the case where the above process is performed for a time period shorter than the above time, a structure satisfying the properties of the present invention is not obtained. In the above process, the shellac reacts with sorbitan dextrin, which is proteolyzed in the condensation, therefore increasing adhesive force.

[61] Upon the stabilization of the emulsion, the cooling process is performed at a temperature of 100⁰C or less. This is because the aging procedure does not efficiently progress at a temperature exceeding the above temperature.

[62] Also, the reason why the temperature for the process of adding the natural casein and performing stirring for reaction is limited to 210~235°C is that insufficient reaction takes place at a temperature below the lower limit, whereas excessive reaction takes place at a temperature above the upper limit, thus making it impossible to perform the reaction satisfying the properties required in the present invention.

[63] Further, in the process of stirring for 1 hour or more, when the stirring is performed for a time period shorter than the above time, a reaction satisfying the properties of the present invention does not sufficiently occur.

[64] Furthermore, the casein, which is in the form of being immersed in water or of containing moisture, is heated to a high temperature to combine it with the protein condensate resulting from the condensation and the natural sorbitan ester so as to form a high binder such as gelatose, thereby completing the reaction.

[65] After the completion of the reaction, the natural binder of the present invention is obtained.

[66] FIG. 2 is a graph illustrating the FT-IR spectra of the variety of compositions for the natural binder of the present invention. Here, FT-IR for structural analysis is adopted to confirm the degree of polymerization of biodegradable materials used in the composition.

[67] As illustrated in the drawing, since the thickness of substituted N-oligo samples in the film varies depending on the amount of oligo (cellulose) side chain, intensity is maintained at 1780-1640 cm, corresponding to the C=O bond region, and IR spectra are compared. In this drawing, it can be seen that, in the N-H stretching region of 3300 cm, the peak representing pure cou malong is substituted depending on the amount of oligo side chain, and also disappears in the N-H bond region of 1540 cm. When the free C=O bond region of 1726 cm, corresponding to the H-bond in natural cou malong, is subjected to N-substitution, it shifts to 1703 cm. This is because the N-substitution of natural cou malong leads to decreased strength of the C=O bond. From this, cellulose is judged to be well synthesized.

[68] In the drawing, (a) is composed of natural carboxymethyl cellulose, (b) of natural carboxymethyl cellulose + natural shellac, (c) of natural carboxymethyl cellulose + natural shellac + natural casein, (d) of natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong, (e) of natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid, and (f) of natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid + natural sorbitan ester starch.

[69] Turning now to FIG. 3, there is an SEM illustrating the surface state of the natural binder of the present invention, comprising natural carboxymethyl cellulose, natural shellac, natural casein, natural cou malong, natural stearic acid, and natural sorbitan ester starch, which are mixed and thus dispersed. The resultant natural binder comprises an emulsion polymer having improved hydrophilicity to thus realize the dispersion and stabilization of the emulsion, resulting in increased water resistance and weather resistance upon use thereof and fast biodegradability of the container after use thereof.

[70] FIG. 4 is an SEM illustrating the surface state of a natural binder, comprising natural carboxymethyl cellulose, natural shellac, natural casein, natural cou malong, and natural stearic acid, which are mixed and dispersed. The natural binder thus completed comprises an emulsion polymer having decreased hydrophilicity, so that the dispersion and stabilization of the emulsion are not realized as desired, resulting in low water resistance and weather resistance upon use thereof and slow biodegradability of the container after use thereof.

[71] FIG. 5 is a graph illustrating the degree of swelling (measured using DMF and water at 25⁰C) of the starch phase of natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid + natural sorbitan ester, constituting the natural binder of the present invention. The natural binder of the present invention is low in the ability to absorb moisture by swelling, and consequently water tightness is increased when producing the container.

[72] FIG. 6 is a graph illustrating the degree of swelling (measured using DMF and water at 25⁰C) of the starch phase natural carboxymethyl cellulose + natural shellac + natural casein + natural cou malong + natural stearic acid, constituting the natural binder, compared to the natural binder of the present invention. In the case where the composition for the natural binder of the present invention has no natural sorbitan ester, the ability to absorb moisture by swelling is high, and water tightness is therefore decreased.

[73] Below a pollution-free disposable container composition, which comprises the natural binder mentioned above and thus may be naturally decomposed and decayed, is described.

[74] The container composition of the present invention is composed solely of completely naturally decomposable materials. The disposable container produced using such a composition is 100% naturally decomposed in the natural atmosphere and thus decayed, thus making it possible to recycle it as compost. The composition of the present invention comprises cereal shells including straw (straw of rice plants, wheat and barley) and chaff (including bran), corn flour (cornstarch), bark of paper mulberry (the material for Korean paper), moss, and a natural binder.

[75] The individual components are finely pulverized in the form of powder, mixed in the component ratio of the present invention, loaded into a mold, and then compressed using a press at a high temperature under high pressure, thus producing a disposable container.

[76] The specific component ratio for the composition of the present invention is as follows.

[77] The cereal shell including straw (straw of rice plants, wheat and barley) and chaff

(including bran) is used in an amount of 1-35 wt%, corn flour (cornstarch) is used in an amount of 1-35 wt%, bark of paper mulberry (the material for Korean paper) is used in an amount of 1-15 wt%, moss is used in an amount of 1-15 wt%, and the natural binder is used in an amount of 10-40 wt%.

[78] Further, the functions and amounts of individual components are specifically described below.

[79] The cereal shells, including straw (straw of rice plants, wheat and barley) and chaff

(including bran), function to exhibit binding force for supporting the framework (shape) of a disposable container. As such, if the amount thereof is less than 1 wt%, binding force is decreased and thus it is difficult to maintain the shape of the container. On the other hand, if the amount exceeds 35 wt%, it is difficult to form the shape thereof.

[80] The corn flour functions as a binding agent for increasing the binding force of the components other than the corn flour. That is, this component acts to prevent the deformation of the container, such as warping, so as to maintain the binding force of the other components and the shape of the container. As such, if the amount thereof is less than 1 wt%, binding force is insufficient. On the other hand, if the amount exceeds 35 wt%, hardness is high but cracking may occur.

[81] In addition, the bark of paper mulberry is used to increase the flexibility and toughness of the container. As such, if the amount thereof is less than 1 wt%, flexibility is deteriorated. On the other hand, if the amount exceeds 15 wt%, structural problems arise, resulting from low hardness.

[82] Moreover, the flexibility and hardness may be maintained depending on the mixing ratio of the bark of paper mulberry and the corn flour.

[83] In addition, the moss functions to increase disinfectant activity. When the amount thereof is less than 1 wt%, disinfectant activity is decreased. On the other hand, when the amount exceeds 15 wt%, binding force becomes insufficient.

[84] Traditionally, moss able to exhibit the disinfectant activity has been used from ancient times, based on the Bon Cho Kang Mok text regarding botanical and medical herb studies, recorded by Lee Si- Jin, a doctor during the Ming Dynasty in China. According to this text, the moss is described as being able to alleviate fever and cure malaria, dyspepsia and bronchial trouble in the human body. Further, according to information retrieved from the Internet about moss, there are many pieces of literature in which the disinfectant activity and antibacterial activity of moss are reported.

[85] In addition, the natural binder is used for binding, tightness, and waterproof coating.

If the amount thereof is less than 10 wt%, the binding force of the other components is weakened. On the other hand, if the amount exceeds 40 wt%, brittleness is increased due to excessive hardness.

[86] Below the compression molding method using a press is described.

[87] 1-35 wt% of cereal shells including straw (straw of rice plants, wheat and barley) and chaff (including bran), 1-35 wt% of corn flour (cornstarch), 1-15 wt% of bark of paper mulberry (the material for Korean paper), 1-15 wt% moss, and 10-40 wt% of natural binder, constituting the composition of the present invention, are prepared and then selected in a predetermined component ratio, after which respective components are finely pulverized, mixed and then compression molded using a press, thus producing a disposable container. The compression molding process is illustratively described below.

[88] However, the following process merely illustrates one apparatus, among various compression methods of producing the container of the present invention, and thus the structure of the apparatus thus illustrated does not represent a limitation on the production of the container composed of the composition of the present invention. The structure of the apparatus of the present invention may be modified as long as it satisfies the preparation conditions of the composition of the present invention.

[89] In the present invention, natural materials, which are mixed using a high-speed mixer and transported and stored in a hopper, are quantitatively fed into the molding part of a mold (a lower mold), heated to 160~180°C and fitted to a 800-1000 ton forming press, via a material feeding device using the rotation of a screw feeder.

[90] As such, a mold having as many lower molds and upper molds as required for simultaneous production of a plurality of products may be used, if necessary.

[91] Further, the reason why the molding temperature is limited to the above range is that a molding process is not performed at a temperature below the lower limit, whereas the natural components are baked at a temperature above the upper limit.

[92] Further, the compression molding process using the forming press is performed in about 1 min. At this time, the fine powder mixture is compressed at a high temperature of 160~180°C under high pressure using a 800-1000 ton forming press, whereby a disposable container is molded in a state in which the upper part thereof is open. Moreover, only when the above numerical conditions are satisfied does adhesion occur in the container of the present invention, so that the container is not burned and not broken in a microwave oven but allows reliable cooking of food material contained therein.

[93] Thereafter, the container thus produced is removed using a product-removing device and then transferred through a conveyor.

[94] Thereafter, the deformities of the molded container transferred through the conveyor are trimmed using the sand paper of a trimming unit.

[95] Thereafter, the trimmed container is treated using an air blowing unit in order to remove dust adhering to the container using air.

[96] Thereafter, the container is subjected to sterilization.

[97] Thereafter, the container is packaged and then discharged.

[98] A better understanding of the present invention may be obtained through the following examples, which are set forth to illustrate, but are not to be construed as the limit of the present invention. Mode for the Invention

[99] [Example 1]

[100] A typical apparatus for manufacturing a natural binder of the present invention, comprising an oil bath having an inlet and an outlet for heating and cooling for temperature control, a reactor having a four-neck flask and provided to the oil bath; and a high-speed stirrer; a nitrogen inlet; a thermometer; and a condenser mounted in respective openings of the four-neck flask of the reactor, is prepared, after which, as the components of a natural binder, 56 wt% of natural carboxymethyl cellulose starch and 22 wt% of sorbitan ester starch and then 1 wt% of stearic acid and 1 wt% of natural cou malong are added into the four-neck flask of the reactor. The oil bath is heated until the thermometer indicates 17O⁰C, so that dehydration and condensation take place. As such, into the four-neck flask where condensation occurs, nitrogen is introduced, therefore forming an inert atmosphere. Further, condensation is caused by the introduced nitrogen, thus producing a condensate.

[101] For reference, the carboxymethyl cellulose starch and the sorbitan ester starch are used in the form of containing moisture upon stirring. To this end, a material comprising the carboxymethyl cellulose starch and the sorbitan ester starch, in which 37 wt% moisture is contained based on the total amount thereof, or a well-dried starch material, containing about 35 wt% moisture, may be used.

[102] When the above components are stirred and heated, a viscous adhesive having good properties may be formed. In such a case, the reaction is as follows.

[103] CH₂-(CH)₂-CH=CH-(CH)₂-CO → -N-CH₂-COO-R

[104] I ²

[105] CH₃ [106] The product thus obtained is efficiently dispersible and wettable and thus becomes a natural proteolytic biodegradable binder.

[107] Subsequently, at 12O⁰C, 10 wt% of natural shellac is fed into the four-neck flask and then stirred for 10 hours. In this step, this component reacts with sorbitan dextrin, which is proteolyzed in the above condensation, thus increasing adhesive force.

[108] Then, the oil bath is cooled to 100⁰C so that the aging process proceeds, thereby stabilizing the emulsion.

[109] When the emulsion is stabilized, 10 wt% of natural casein is supplied into the four- neck flask, and thus the stabilized reaction emulsion is stirred at 21O⁰C for 1 hour in a nitrogen-introduced inert atmosphere to allow it to slowly react, thereby completing the natural binder.

[110] More particularly, the casein, which is in the form of being immersed in water or of containing moisture in an amount twice that of the casein, is heated to a high temperature to combine it with the protein condensate and the natural sorbitan ester as natural fatty acid ester so as to obtain a high binder such as gelatose, thereby completing the reaction.

[I l l] In the natural binder thus completed, as shown in FIG. 3, the dispersion and stabilization of the emulsion are efficiently realized thanks to the increased hydrophilicity of emulsion polymer, resulting in high water resistance and weather resistance upon use and fast biodegradability of a container after use.

[112] Further, as shown in FIG. 5, since the natural binder is low in the ability to absorb moisture by swelling, water tightness is increased upon use of the container.

[113]

[114] [Example 2]

[115] A manufacturing apparatus is constructed as in Example 1, after which the manufacturing process, comprising:

[116] adding 45 wt% of natural carboxymethyl cellulose starch and 24 wt% of natural sorbitan ester starch with 2 wt% of natural stearic acid and 2 wt% of natural cou malong, and then introducing nitrogen to thus form an inert atmosphere, such that dehydration and condensation occur at 175⁰C in such an atmosphere;

[117] adding 14 wt% of natural shellac and performing a stirring process at 125⁰C for 10 hours for reaction;

[118] cooling the reaction product to 100⁰C to thus age it, thereby stabilizing an emulsion; and

[119] adding 13 wt% of natural casein to the stabilized emulsion and then stirring the emulsion at 235⁰C for 1 hour in a nitrogen-introduced inert atmosphere, is carried out.

[120]

[121] [Example 3] [122] A method of producing a container using the pollution-free disposable container composition composed of the natural binder of Example 1 is as follows.

[123] 30 wt% of cereal shell, 20 wt% of corn flour, 5 wt% of bark of paper mulberry, 5 wt% of moss, and 40 wt% of the natural binder are mixed using a high-speed mixer, transferred into a hopper and stored therein, and then quantitatively fed into the molding part of a mold (a lower mold), which heated to 18O⁰C and fitted to a 1000 ton forming press, via a material feeding device using the rotation of a screw feeder. Subsequently, a compression molding process is carried out for 1 min using the forming press, thereby producing a pollution-free disposable container.

[124]

[125] [Comparative Example 1]

[126] A typical apparatus for manufacturing a natural binder of the present invention, comprising an oil bath having an inlet and an outlet for heating and cooling for temperature control, a reactor having a four-neck flask and provided in the oil bath; and a high-speed stirrer; a nitrogen inlet; a thermometer; and a condenser mounted in respective openings of the four- neck flask of the reactor, is prepared, after which 78 wt% of natural carboxymethyl cellulose starch and then 1 wt% of stearic acid and 1 wt% of natural cou malong are added into the four-neck flask of the reactor. The oil bath is heated until the thermometer indicates 17O⁰C, such that dehydration and condensation take place. As such, into the four-neck flask where condensation occurs, nitrogen is introduced to thus form an inert atmosphere.

[127] Then, at 12O⁰C, 10 wt% of natural shellac is fed into the four-neck flask and stirred for 10 hours.

[128] Then, the oil bath is cooled to 100⁰C so that the aging process proceeds, thereby stabilizing the emulsion.

[129] When the emulsion is stabilized, 10 wt% of natural casein is fed into the four-neck flask, and thus the emulsion is stirred at 21O⁰C for 1 hour to allow it to slowly react in a nitrogen-introduced inert atmosphere, thereby completing the natural binder.

[130] In the natural binder thus completed, as shown in FIG. 4, the dispersion and stabilization of the emulsion are not realized as desired due to the decreased hy- drophilicity of emulsion polymer, resulting in low water resistance and weather resistance upon use and slow biodegradability of the container after use.

[131] Further, as shown in FIG. 6, the ability to absorb moisture by swelling is high, undesirably resulting in low water tightness upon use of the container.

[132] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Industrial Applicability As described above, the natural binder of the present invention is advantageous because it has superior thermal and mechanical properties and chemical resistance and also is better in terms of fast curability, melt injection upon working, and easy workability, compared to conventional thermosetting resins and biodegradable resins, therefore resulting in excellent adhesive force. Further, 98% of container products molded from a composition for a pollution-free disposable container using the natural binder of the present invention can be decomposed within six months when buried underground (based on a depth of 50 cm), thereby drastically reducing environmental pollution. Accordingly, the present invention is expected to have high industrial applicability.

Claims

[1] A natural binder for binding natural powder for use in a container, comprising

45-56 wt% of natural carboxymethyl cellulose starch, 9-14 wt% of natural shellac, 8-13 wt% of natural casein, 20-28 wt% of natural sorbitan ester starch, 0.5-2 wt% of natural cou malong, and 0.5-2 wt% of natural stearic acid.

[2] A method of manufacturing a natural binder for binding natural powder, comprising: preparing components for a natural binder, including 45-56 wt% of natural carboxymethyl cellulose starch, 9-14 wt% of natural shellac, 8-13 wt% of natural casein, 20-28 wt% of natural sorbitan ester starch, 0.5-2 wt% of natural cou malong, and 0.5-2 wt% of natural stearic acid, and then selecting amounts of the components according to a predetermined component ratio; adding the natural carboxymethyl cellulose starch and the natural sorbitan ester starch with the natural stearic acid and the natural cou malong, selected according to the predetermined component ratio, heating them to 170- 175⁰C, and then introducing nitrogen to thus form an inert atmosphere for condensation, so that dehydration and condensation take place; adding shellac to a condensation product, and then stirring the condensation product at 120- 125⁰C for 10 hours or more to allow it to react; cooling a reaction product to 100⁰C or lower to thus age it, therefore stabilizing an emulsion; and adding natural casein to the stabilized emulsion, and then heating and stirring the emulsion at 210~235°C for 1 hour or more in a nitrogen-introduced inert atmosphere to allow it to slowly react.