COMPOSITIONS FOR A DISPOSABLE FOOD CONTAINER USING FLOUR TECHNICAL FIELD The present invention relates to compositions for a disposable food container using natural materials such as flour and the like and a method for manufacturing a disposable food container. More particularly, the disposable food container of the present invention is formed of flour, or tapioca powder, or funori and pulp, or cotton yarn as a primary material, and sodium bicarbonate, alum and glycerine as supplementary materials. A disposable food container according to the present invention is prepared by mixing, gelatinizing, foaming in a heat/pressure molder, and coating the primary materials and the supplementary materials dissolved in water.

BACKGROUND ART Most disposable containers being widely used currently are ones formed by foaming and compression-molding synthetic resin such as polystyrene or the like, and ones formed by jetting synthetic resin on the surface of paper which is a primary material.

It is a trend that the use amount of disposable containers increases every year with more fast food consumed in food-related life style amongst our contemporaries. However, said conventional containers contain chemicals harmful to human bodies and the problem of disposing of the used containers is growing more serious according to the increase of the use amount of the

containers.

Accordingly, in recent, researches and developments are actively ongoing that replace the polystyrene with natural polymer materials which can be obtained from grain starch or wheat flour, grain skins, and so on. As illustrations using grain powder, there exists a method molding, freezing, and coating dough obtained from mixing wheat flour, starch, sodium bicarbonate, and salt (Republic of Korea Patent No. 96-0006565), a method aging, extruding, molding, and freeze- drying dough obtained from mixing purified water of proper temperature with grain starch and wheat flour as primary materials and sugar, spices, yeast, and so on as supplementary materials (Republic of Korea Patent No. 99-0047173), and the like.

Further, as illustrations using grain skins, there exists a method mixing ground skins of rice, barley, foxtail millet, Indian millet and so on, water, and starch, molding, and then coating for final products (Republic of Korea Patent No. 99- 0055567), and a method wherein plant particles as a basic material are obtained from grinding corn stalks or various grain skin, mixed with edible gelatin, compressed through a molder for final products (Republic of Korea Patent No. 99- 0037967), and so on.

However, such products are so heavy, fragile, and shrunk due to ambient temperatures that lots of limitations are applied in use. Even though natural polymers are used as primary materials in order to solve the problems, indecomposable additives are inevitably used in many occasions. Therefore, there still exists decomposability problems as well as difficulties in practical usage due to high prices.

DISCLOSURE OF INVENTION It is an object of the present invention to provide disposable containers for wrapping food which are relatively inexpensive, light-weighted, less fragile, and less deformed and prepare from natural materials which can replace polystyrene causing environment pollution and harmful to human bodies.

BEST MODES FOR CARRYING OUT THE INVENTION In order to achieve the above objects, flour, or tapioca powder or funori was used as a primary material instead of polystyrene and pulp or cotton yarn was used as binder for disposable containers according to the present invention.

Sodium bicarbonate and alum were used as supplementary materials, and glycerine was added for product flexibility.

It was preferable that flour or tapioca powder or funori as primary material was mixed with pulp or cotton yarn as binder in a ratio of 3-7: 7-3 by weight %. A ratio of the mixture of flour, tapioca powder, and funori to the binder is most preferably 7: 3. There occurred drawbacks in that a high binder ratio caused difficulties in foam-molding products, products to hard, and a low binder ratio caused fragile products of low strength. It was preferable that other materials were mixed with 1-2 weight % sodium bicarbonate, 1-2 weight % alum, and 1-2 weight % glycerine.

As below is a method for manufacturing disposable food containers with the above materials according to the present invention.

Flour or tapioca powder or funori and pulp or cotton yarn were mixed in a

predetermined rate for preparing a primary mixture, and the supplementary materials such as sodium bicarbonate, alum and glycerine were dissolved in water, and were mixed with the primary mixture. The mixture was steamed or boiled at temperatures of 100- 120°C for gelatinization. The gelatinized dough was foamed in a heat/pressure mold. It was preferable to maintain the temperatures of mold heat wires at 130-220°C upon the heat/pressure molding. Further, the heating and pressurizing period of time when heat/pressure molded was preferably one or two minutes. A molded container was separated, sprayed with or dipped into a biodegradable coating agent, and dried.

Hereinafter, a process for manufacturing disposable food containers according to the present invention is described in detail in following embodiments.

EXAMPLE 1 Flour powder was mixed with cotton yarn in a rate of 70: 30 (70g: 30g) to prepare material 1. A solution in which 1-2g alum and 1-2g glyceline were dissolved in 70g water was mixed and stirred with the material 1 in the same rate, and was steamed in a steam pot at temperatures of 100- 120°C to prepare gruel.

The gruel was mixed with 1-2g sodium bicarbonate, the temperatures of mold heat wires were maintained at 130-220°C, and then a certain amount of the gruel was put in a mold. The mold was closed and pressed for 1-2 minute foam molding and drying. A biodegradable coating agent was sprayed inside and outside containers and dried. A sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 2 Flour powder was mixed with pulp in a rate of 70: 30 (70g: 30g) to prepare material 1. A solution in which 1-2g alum and 1-2g glyceline were dissolved in 70g water was mixed and stirred with the material 1 in the same rate, and was steamed in a steam pot at temperatures of 100- 120°C to prepare gruel. The gruel was mixed with 1-2g sodium bicarbonate, the temperatures of mold heat wires were maintained at 130-220°C, and then a certain amount of the gruel was put in a mold. The mold was closed and pressed for 1-2 minute foam molding and drying. A biodegradable coating agent was sprayed inside and outside containers and dried. A sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 3 Tapioca powder was mixed with cotton yarn in a rate of 70: 30 (70g: 30g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 4 Tapioca powder was mixed with pulp in a rate of 70: 30 (70g: 30g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was

tasted for tensile strength and Table 1 shows the result.

EXAMPLE 5 Funori was mixed with cotton yarn in a rate of 70: 30 (70g: 30g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 6 Funori was mixed with pulp in a rate of 70: 30 (70g: 30g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 7 Tapioca powder was mixed with pulp in a rate of 80: 20 (80g: 20g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

EXAMPLE 8 Tapioca powder was mixed with cotton yarn in a rate of 80 : 20 (80g: 20g) to prepare material 1. A container was prepared by the same method as in the example 1, and a sample of 1cm wide and 3cm long prepared from the dried container was tasted for tensile strength and Table 1 shows the result.

Table 1 Tested Exam le No. Item 1 2 3 4 5 6 7 8 TENSILE Width 10.8 9. 44 8.04 8.42 7.87 7.87 5.12 6.20 STRENGT H Length 14. 4 11.2 11.0 11.3 10.9 10.9 5.66 7.74 (kgf/ 15mm) INDUSTRIAL APPLICABILITY The present invention foams natural materials to fabricate disposable containers, so as to solve the weakness of conventional natural material-based disposable containers, that is, the problems of fragility or deformation and weight.

As shown in the result of the test for tensile strength, the present invention provides environment-friendly disposable containers which are light-weighted but less damaged or deformed.