SHEET COMPOSITION USING BAMBOO Technical Field [1] The present invention relates to a sheet composition using bamboo, and more par¬ ticularly, to a sheet composition using bamboo exhibiting superior properties in tensile strength, bending strength, bending elasticity, and heat resistance, in which bamboo is pulverized and blended with thermoplastic resin such as polypropylene (P.P) in a pre¬ determined ratio so that a sheet that is a finished product is environment-friendly, recyclable, and made compact. Background Art [2] In a conventional method, a sheet is manufactured by pulverizing a wood material that is a natural textile and blending the pulverized wood portion with resin such as polypropylene. Since wood needing tens of years to grow to be a matured wood is used, there is a problem such as the destruction of environment and a limit in the supply of a material. Since the strength of the wood itself is weak, the properties such as tensile strength and bending strength is deteriorated during the manufacture of a sheet that is a finished product. In particular, since the thickness of the sheet needs to be manufactured thick to satisfy the property of a product such as car interior parts which need strength, the product is heavy. Thus, when the product is used as the car interior sheet, gas mileage is lowered, workability is deteriorated, and the production costs increase. Disclosure of Invention Technical Problem [3] To solve the above and/or other problems, the present invention provides a sheet composition using bamboo exhibiting superior properties in tensile strength, bending strength, bending elasticity, and heat deformation temperature, which is environment- friendly and recyclable and simultaneously made compact compared to a conventional sheet manufactured by blending wood powder made by pulverizing wood with synthetic resin. Technical Solution [4] According to an aspect of the present invention, a sheet composition using bamboo comprises a bamboo fiber 35.0-65.0 wt%, as a main material for an entire sheet composition, formed of 50% or more of a bamboo component obtained by pulverizing and cutting bamboo to be 3-8 mm long to have a needle shape structure and less than 50% of a bamboo component obtained by pulverizing and cutting bamboo to be less than 3 mm or greater than 8 mm long to have a needle shape structure, thermoplastic resin of 31.0-55.0 wt% such as polypropylene, polyethylene, A.B.S., polystylene, polyvinyl chloride (P.V.C), or P.E.T exhibiting a heat distortion temperature (HDT) of 90 ° C or more, maleic anhydride deformed polypropylene 3.8-9.0 wt% that is a com¬ mercialization agent, as a sub-material, to increase a coupling force between the bamboo fiber and anti-heat resin, and calcium stearate (Ca-st) of 0.05-0.04 wt% that is a heat stabilizer, a penol/phosphorous deoxidizer of 0.05-0.2 wt% made by mixing penol and phosphor for deoxidization, and carbon-black of 0.1-0.4 wt% that is a pigment, as other additives Advantageous Effects [5] As described above, the sheet composition using bamboo according to the present invention is formed of 50% or more of a bamboo component obtained by pulverizing and cutting bamboo to be 3-8 mm long to have a needle shape structure and less than 50% of a bamboo component obtained by pulverizing and cutting bamboo to be less than 3 mm or greater than 8 mm long to have a needle shape structure. Thus, compared to a conventional sheet using wood powder, the thickness of a sheet can be reduced over 20-30% so that a finished product sheet can be made light and workability is improved. In particular, although the product is made light, the major strength properties such as tensile strength, bending strength, bending elasticity, and heat distortion temperature are enhanced. Also, when the bamboo fiber is used as an interior sheet for a car, consumption of gas is improved. Best Mode [6] In the present invention, to facilitate blending with thermoplastic resin, bamboo fiber of 35.0-65.0 wt%, preferably, 38.0-60.0 wt%, made of 50% or more of a bamboo component obtained by pulverizing and cutting bamboo to be 3-8 mm long to have a needle shape structure and less than 50% of a bamboo component obtained by pulverizing and cutting bamboo to be less than 3 mm or greater than 8 mm long to have a needle shape structure. [7] [Bamboo fiber related image] [8]

[9] For the thermoplastic resin of the present invention, polypropylene, polyethylene, A.B.S., polystylene, polyvinyl chloride (P.V.C), or P.E.T exhibiting a heat distortion temperature (HDT) of 90 ° C or more is used at a content of 31.0-55.0 wt%. Preferably, high crystal polypropylene having an isotatic structure in which a metyl group is arranged in the same direction as a main chain described below is used at a weight portion of 35.5-55.0 wt%. [10]

[H] Also, to increase a coupling force between the bamboo fiber and thermoplastic resin or between polypropylene and polypropylene, a product name 'CM-1120' man¬ ufactured by Honam Petrochemical Corporation, a product name 'KH-845-4' man¬ ufactured by Acentech Corporation, or a product name 'SILQUEST-A- 151' man¬ ufactured by Doo Lee KC Co., Ltd. which are maleic anhydride deformed polypropylene having a structure in which a functional group at an end thereof has a hydroxyl group, an amino group, or a carboxyl group as polypropylene grafted to have a functional group, is used as a commercialization agent at a content of 3.8-9.0 wt%. Preferably, CM-1120 is used at a content of 4.0-6.5 wt%. [12] As other additives, calcium stearate (Ca-st) that is a heat stabilizer for thermal sta¬ bilization is used at a content of 0.05-0.04 wt%, preferably, 0.2 wt%. BB 021 man¬ ufactured by Asia Additives Corporation which is a penol/phosphorous deoxidizer made by mixing penol and phosphor for deoxidization is used at a content of 0.05-0.2 wt%, preferably, 0.1 wt%. Carbon-black is used as a pigment at a content of 0.1-0.4 wt%, preferably, 0.2 wt%. [13] In the present invention having the above composition, to fit to a product requiring high strength and simultaneously lightness such as interior parts of a car, bamboo is obtained by pulverizing and cutting bamboo such that bamboo fiber is made of 50% or more of a bamboo component obtained by pulverizing and cutting bamboo to be 3-8 mm long to have a needle shape structure and less than 50% of a bamboo component obtained by pulverizing and cutting bamboo to be less than 3 mm or greater than 8 mm long to have a needle shape structure. Thus, the bamboo fiber is well blended with high crystal polypropylene that is thermoplastic resin. Also, to increase a coupling force between the bamboo fiber and thermoplastic resin, as a commercialization agent, maleic anhydride deformed polypropylene having a structure in which a functional group at an end is a hydroxy 1 group, an amino group, or a carboxyl group is used as polypropylene grafted to have a functional group. Thus, the thickness is reduced by 20-30% or more compared to that of the conventional sheet using a portion made of pulverized wood so that a finished sheet can be made light. Although the weight of a product is reduced, the major properties such as tensile strength, bending strength, or bending elasticity are enhanced. [14] Since the present invention is not limited to the following embodiments, the below described embodiments should not be interpreted to limit the scope of protection of the present invention. [15] An embodiment is manufactured in a well-known blending and extrusion method for manufacturing a sheet with a composition ratio (content: wt%) as shown in Table 1. A comparative example is a product used as an interior sheet for a car manufactured in the same manufacturing method as that of the embodiment at the composition ratio (content: wt%) as shown in Table 2. Table 3 shows the result of analysis of major properties of the embodiment and comparative example. [16] [Table 1] [17] [Unit: wt%] [18]

[19] [Table 2 ] [20] [Unit: wt%] [21]

[22] [Embodiment 1] [23] A sheet having a thickness of 2.0 mm is manufactured using a well-known extruder by blending bamboo fiber 49.5 wt%, high crystal p.p. 45.0 wt%, maleic anhydride deformed p.p. (product name: CM-1120) 5.0 wt%, calcium-stearate that is a heat stabilizer 0.2 wt%, an deoxidizer (product name: BB-021) 0.1 wt%, and carbon-black that is a pigment 0.2 wt%, in which the bamboo fiber consists of a bamboo component 55% having a 7 mm long needle shape structure obtained by pulverizing and cutting the bamboo, a bamboo component 20% having a 10 mm long needle shape structure, and a bamboo component 25% having a 1.5 mm long needle shape structure. [24] [Embodiment 2] [25] A sheet having a thickness of 2.0 mm is manufactured using a well-known extruder by blending bamboo fiber 49.5 wt%, high crystal p.p. 50.0 wt%, maleic anhydride deformed p.p. (product name: CM-1120) 4.5 wt%, calcium-stearate that is a heat stabilizer 0.2 wt%, an deoxidizer (product name: BB-021) 0.1 wt%, and carbon-black that is a pigment 0.2 wt%, in which the bamboo fiber consists of a bamboo component 55% having a 7 mm long needle shape structure obtained by pulverizing and cutting the bamboo, a bamboo component 20% having a 10 mm long needle shape structure, and a bamboo component 25% having a 1.5 mm long needle shape structure. [26] [Comparative example] [27] A sheet having a thickness of 2.0 mm and used as an interior sheet for a car is man¬ ufactured using a well-known extruder by blending wood powder 44.8 wt%, common p.p. 48.8 wt%, targ 6.0 wt%, a deoxidizer (product name: BB-021) 0.2 wt%, and carbon-black that is a pigment 0.2 wt%. [28] [Specific gravity test method] ASTM D792 [29] [Tensile strength test method] ASTM D638 [30] [Bending strength, bending elasticity test method] ASTM D790 [31] [HDT test method] ASTM D648 [32] [Table 3] [33]

[34] As shown in the above Table, for a sheet having a thickness of 2.0 mm man¬ ufactured in the same manufacturing process, the compositions of the embodiments 1 and 2 according to the present invention exhibit superior property compared to that of the comparison example. In particular, the embodiments 1 and 2 exhibit superior strength by revealing their tensile strength and bending strength more than two times stronger than the comparison example. Thus, a product can be made light and the bending strength and HDT are superior by far to the comparison example. Industrial Applicability [35] As described above, the sheet composition using bamboo according to the present invention is formed of 50% or more of a bamboo component obtained by pulverizing and cutting bamboo to be 3-8 mm long to have a needle shape structure and less than 50% of a bamboo component obtained by pulverizing and cutting bamboo to be less than 3 mm or greater than 8 mm long to have a needle shape structure. Thus, compared to a conventional sheet using wood powder, the thickness of a sheet can be reduced over 20-30% so that a finished product sheet can be made light and workability is improved. In particular, although the product is made light, the major strength properties such as tensile strength, bending strength, bending elasticity, and heat distortion temperature are enhanced. Also, when the bamboo fiber is used as an interior sheet for a car, consumption of gas is improved.