BACKGROUND ART Conventionally, the processed lumber was generally used as materials for building interior and chaff, rice straw and sawdust, which were blended with industrial adhesive and thereafter cold-pressed also were used. Korean Patent Publication No. 86-1688 disclosed the manufacturing method of boards from rice straw and Korean Utility Model Publication No. 71-1753 relates to the synthetic resin boards.

In the above Patent, minutely cut crop straws were used with adhesives such as acacia gum, glue, starch pastes, and in the above Utility Model for manufacturing building materials rice straw and chaff were hot pressed.

In prior arts, the building materials were produced through hot pressing wastes, but there were problems that the manufacturing processes were complicated and that the materials were ineffective in soundproofing, vapor-proofing and heat insulation.

The present invention, taking the above circumstances into consideration, utilize coconut shells which were not used in other objects but only wasting, and which were known as domestic wastes not easily decomposed by microorganisms.

Ligenous components are mainly cellulose, hemicellulose and lignin, which comprise carbon, oxygen and hydrogen.

Generally, dried coconut shells are rapidly oxidized and decomposed by heating about 280°C and emit gases such as COx, CO, H2 and CH3. Elevating heating temperature up to 650°C~700°C, the content of 02 and H2 in the emitted gases decreases and the degree of crystallization as activated carbons increases.

Besides, heating dried coconut shells over 1,800°C, the black carbide of coconut shells is produced in the shape of crystalline diamond. The higher gets the heating temperature, the larger the content of carbon. According to experiments executed by the present inventors, when heating over 1,800°C, the carbon content of the activated carbon gets to 95% in maximum.

Carbonized coconut shells have the vesicular structure, in which numerous micropores are formed and thereby have the functions of deodorization, dehumidification and filtration. Negatively charged carbide of coconut shells emits a lot of anions and adsorbs cations, by that means it makes the indoor environment comfortable and beneficial to human health. Furthermore, the carbide of coconut shells adsorbs noxious electromagnetic waves radiated from various kinds of electronic products and can intercept the man's disclosure to the noxious electromagnetic waves indoor place.

Conventionally disclosed and used materials for building interior contain many hazardous chemicals such as carcinogenic xylene, DBP, TOP, decane and so forth. Therefore, when people move into newly-built residences, they live in the residing space which deserves to be called as the space of poisonous gases. Thereby, many people get to have asthma, atopic dematitis, headache, malaise and so forth.

In the present invention, coconut shells, which are grown at the subtropical zone and the tropical zone, are used. The degree of carbonization of the coconut shells is required preferably dry-distilled coal or open-hearth coal carbonized at 400°C~500°C, more preferably black coal carbonized at 600°C~700°C, and most preferably white coal carbonized over 1,000°C. Generally, charcoal emits the energy of 6,700cal/g at 400°C, 8,000cal/g at 600°C, and 7,000cal/g over 1,000°C.

Accordingly, at the grade of black coal the mass of emitted energy is maximum and at the grade of white coal the mass of emitted energy decreases rather than black coal, for during carbonization the carbon content increases and the hydrogen content decreases as raising heating temperature.

Then, heating coconut shells about 300°C, organic substances in the coconut shells are rapidly carbonized and decomposed, and gases such as C02, CO, H2 and CH3 are emitted, and the carbon content increases, thereafter amorphous carbon coagula is formed. Raising the heating temperature over 700°C, as the emission of Oz, H2 decreases, the nature of coconut shell surface changes and the black coal is produced. Heating coconut shells over 2,000°C, the crystallization advances and the carbide of coconut shells becomes like crystalline diamond.

Having difference according to grown district, the carbon content of coconut shells at the state of raw material is about 50%, and after carbonization at 400 °C the carbon content gets to 70%, and at 700 °C to 90%, and over 1,000°C to 95%.

These coconut shell based activated carbon, produced over mesothermen, have the vesicular structure having numerous micropores. These activated carbons have the functions of deodorization, dehumidification and filtration, and are very effective in soundproofing, heat insulation, heat conservation and fire-proofing, and have the availability of processing such as nailing and sawing, and are good for interrupting hazardous waves such as electromagnetic wave and waterway wave.

Accordingly, the present invention has an object to provide a novel material for building interior which is effective in soundproofing, heat insulation, heat conservation and fire-proofing, and which has the availability of processing such as nailing and sawing, and which is good for interrupting hazardous waves such as electromagnetic wave and waterway wave as aforementioned.

Another object of the present invention is to provide the manufacturing method of said novel material for building interior.

DISCLOSURE OF THE INVENTION

In order to accomplish the above objects, the present invention provides a material for building interior in the shape of board through the processes comprising: carbonizing coconut shells over mesothermen ; grinding the activated carbon produced by carbonizing process; mixing grinded activated carbon with natural vegetable aqueous adhesive; cold pressing the mixture; and drying. And, to accomplish the above objects, the board-type building interior produced through said processes was estimated by various experiments.

Hereinafter, the exemplary illustrations of the present invention are described in detail, but by no means limited by the following illustrations.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a process diagram of the exemplary illustration according to the present invention; and Fig. 2 is a photograph showing the material for building interior by the process of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION The exemplary illustration of the present invention is described in Fig. 1.

According to Fig. 1, the manufacturing process of the novel material for building interior comprises: carbonizing the collected coconut shells over mesothermen; grinding the activated carbon coagula of coconut shells with the hammer-type grinder; mixing natural vegetable aqueous adhesive with grinded activated carbon; cold pressing the mixture; and drying the board-type material for building interior which is molded by cold pressing.

Hereinafter, the manufacturing method of the material for building interior of the present invention is described in detail.

Process (Carbonization)

The carbonized coconut shells have the characteristic of high stiffness and uniform distribution of micropores. After coconut shells are inserted into the Rotary Kiln, heating with paraffin oil burner over 1,800°C, the organic substances in the coconut shells are decomposed.

2nd Process (Grinding) Because the cooled coagula of the coconut shell based activated carbon is very stiff, they are grinded into granules by hammer-type grinder not manually. If required, thereafter the vacuum adsorption process may be added, for the purpose of removing the activated carbon dust.

3rd Process (Mixing with aqueous adhesive) For the convenience of molding the board-type building interior, the natural vegetable aqueous adhesive, prepared specially, is mixed with granular activated carbons obtained through said 2nd process. The specially prepared adhesive is preferably a kind of the natural vegetable aqueous adhesives, which is harmless to man as the building interior. The mixing rate of the activated carbon and the aqueous adhesive is preferably 7-8 : 3-2 by weight.

The aqueous adhesive is prepared by the composition of said activated carbon 4kg, amylopectin 600g, amylose 200g and water (Ha0) 3kg. Namely, the composition of aqueous adhesive is preferable at the rate of water (H20) 75%-85%, amylopectin 10%-20%, amylose 1%-10% by weight.

4th Process (Hot-Pressing) The mixture of said 3rd process is inserted into the Hot Press and executing hot-pressing over 90 °C. The moment, the time of hot-pressing is preferably maintained for 5-10 minutes.

5th Process (Drying) The board-type material for building interior produced by said hot

pressing process is dried and solidified with hot blast over 90 °C for 4 hours. The product of the present invention is provided for the various experiments.

Hereinafter, the following examples and experiments are provided to illustrate preferred embodiments of the present invention, the preferred manufacturing method and comparative evaluations with prior art.

Example 1 Coconut shells 10kg were inserted into the Rotary Kiln and heated at 1,800°C for one hour with a paraffin oil burner. The carbide coagula of coconut shells 4.5kg, left after heating decomposition, were put into the hammer-type grinder and grinded into granules. The Homogenizer uniformly mixed the granular activated carbon 4.5kg with the natural vegetable aqueous adhesive 2kg.

Said mixture 6kg was hot pressed at 90°C for 7 minutes, and the hot pressed mixture was cut into boards of 30cm thickness, and the boards were dried with hot blast for 4 hours. Then, a box was made of said boards, and the box has 40cm length and 40cm width (Fig. 2).

Example 2 After grinding process of said Example 1, the activated carbon dust was removed from the granular activated carbons with the vacuum adsorber. Because the natural aqueous adhesive is used in the material for building interior of the present invention, noxious gases are not emitted, apart from conventional materials for building interior, and moreover the function of adsorbing noxious gases makes a comfortable indoor environment. As well, the vegetable aqueous adhesive, used in the present invention, is prepared by utilizing the tackiness of amylopectin and the coagulation of amylose and heating at 80 °C in water, so that the adhesive is the a- starch pastes in the semitransparent liquid state and convenient for use. Moreover, in the processes of the present invention, the water molecules in the mixture of the adhesive and the granular activated carbons are evaporated at the state of hot-

pressing over 90 C about 5 minutes, and through the retrogradation of starch, due to the cohesion of amylose with amylopectin, the granular activated carbons are solidified, and the regradation of starch is completed by re-drying over 90 °C.

The characteristics and effects of the material for building interior of the present invention were estimated by the various experiments.

Experiment 1: Noxious gases.

After deformation processing for the preparation of fire, the material for building interior of the present invention was heated at 100°C, but noxious gases such as ammonia, sulfur dioxide, hydrogen and so forth were not emitted at all.

Experiment 2: Effect of heat insulation.

Through contacting the material of the present invention with burner, the effect of heat conduction was estimated, but the heat conduction was infinitesimal.

Experiment 3: Estimation of the performance for construction work.

Estimating the performance for construction work, nailing spikes could not bring about crevice on the material of the present invention, and cutting in the desired direction was very easy.

Experiment 4: Effect of soundproofing.

After a 6.6 m2-area room was made of the activated carbon boards and a control plot was made of conventional plasterboards, soundproof test was executed.

As the result, it was confirmed the fact that soundproof effect was improved by 3.5- fold compared to the control plot, because the porous surface of the material of the present invention adsorbed particular bandpass of sound.

Experiment 5: Effect of purifying indoor environment After making a box, the dimension of 40 x 40 x 40 cm, of the material of the invention and inserting lettuce into said box, and keeping in during 3 days as a

control plot made of plaster boards, the freshness of lettuce was estimated. So that, the freshness of lettuce in the former was maintained over the level of 90%.

Experiment 6: Effects of deodorization and adsorbing noxious gases.

Inserting each 30 cigarette-butts and one loaf of bread into said boxes in experiment 5 and keeping in for 2 days, the bread in the box made of the material of the present invention did not smell at all.

Experiment 7: Effect of vapor-proofing.

After wet cotton spread in two schales and put a nail on each schale, one of the schales was inserted into the box made of the material of the present invention in the experiment 5 and the other into the plaster board box for one week. As the result of estimating the corrosion degree of the nails, no rust was observed in the nail kept in the box made of the material of the present invention.

INDUSTRIAL APPLICABILITY As described above, the present invention provides a novel material for building interior and the manufacturing method thereof. The material for building interior of the present invention, which is made from coconut shells and natural aqueous adhesive, does not emit noxious gases at all but adsorb noxious gases emitted from other combustibles when a fire breaks out, thus the safety of the material of the present invention is very high. Moreover, the material of the present invention has the high performance for construction such as nailing and sawing and is very effective in heat insulation, soundproofing, dehumidification, heat conservation, and fireproofing. As well, the activated carbons contained in the material of the present invention emit numerous anions and adsorb cations and kinds of hazardous waves, thus the material of the present invention is very effective in maintaining the indoor environment comfortable. The material for building interior of the present invention is thus highly applicable in building interior industrial field.