Description

MANUFACTURING METHOD OF PURIFIED URUSHIOL FOR

ADDITION INTO SYNTHETIC RESIN AND PURIFIED

URUSHIOL MANUFACTURED BY THE SAME

Technical Field

[1] The present invention relates to a method of manufacturing purified urushiol for addition to synthetic resin and purified urushiol manufactured thereby, and more particularly, to a method of manufacturing purified urushiol for addition to synthetic resin, in which unsaturated urushiol, contained in crude lacquer, is converted into saturated urushiol through hydrogenation, and to purified urushiol manufactured using the same. Background Art

[2] The lacquer tree (Rhus verniciflua or Rhus vernicifera) is a deciduous tree classified as Anacardiaceae, the original habitat of which is the Middle Asia highlands and Himalayan regions. The lacquer tree is presently widely distributed in many regions around the world, including tropical, subtropical, and temperate regions, and is mainly cultivated to obtain oriental lacquer in Southeast Asian regions including Korea, Japan and China.

[3] The lacquer tree, from which crude lacquer or lacquer sap is collected, has been known since ancient times to be effective in eliminating blood aggregation, in promoting blood circulation, in exterminating insects, and in treating stomachaches, gastric hyperacidity, cough, phthisis, menstrual cramps, constipation, glycosuria, and malaria, in the oriental medicine field. In recent years, anticancer effects have been reported. Furthermore, in Korea, the lacquer tree has been applied to chickens or ducks to improve people s health or for medicinal uses. In addition, the lacquer sap is durable and thus has been used as natural paint in large amounts, mainly by being applied on wood to produce articles for living, including wardrobes, vessels, spoons, chopsticks, and tables. It is also known that the lacquer sap has advantages such as high flame resistance, heat resistance, rot resistance, insect resistance, and electrical insulation properties, and furthermore, that the preservative quality thereof is good.

[4] The lacquer sap is composed of urushiol, water, rubber, laccase, and nitrogen- containing substances. Among these, urushiol plays a role as a main component, constituting about 70% of the lacquer sap and consists of 3-substituted catechol complex having C -alkyl or alkenyl groups, and the main ingredient thereof is 3-(8'Z, 11 'Z, lS'Z-pentadecatrieny^catechol, having three double bonds. 13 components of 3-substituted alkyl catechol, in which the number of double bonds in the C side chain is 0, 1, 2, or 3, have been established (Yumin Du and Ryuichi Oshima, J. of Chro-

matography, 284, 463-473 (1984)). Urashiol includes polymers resulting from natural polymerization of these monomers with laccase (Yamauchi, Y., T. Murakami and J. Kumanotani, J. of Chromatography, 214, 343-348 (1981); Yamauchi, Y., R. Oshima and J. Kumanotani, J. of Chromatography, 243, 71-84 (1982); and Y. Du, R. Oshima and H, Iwatsuki, J. of Chromatography, 295, 179-186 (1984)). Generally, in the case where the lacquer is used as paint, the higher the urushiol content contained in natural lacquer, the greater the quality and quantity.

[5] With regard to a method of manufacturing a urushiol fraction (Korean Patent Application No. 10-1997-0013163) and to urushiol-ethanol nanoparticles having excellent anticancer effects, a manufacturing method thereof, and an anticancer composition containing the same (Korean Patent Application No. 10-1999-0016473), various attempts to purify urushiol have been made. However, research on the purification of urushiol to make it suitable for addition to synthetic resin to use it as various industrial materials is still insufficient. Disclosure of Invention Technical Problem

[6] Accordingly, an object of the present invention is to provide a method of manufacturing purified urushiol, which may be easily mixed when added to synthetic resin, including PA (poly amide), PC (polycarbonate), PE (polyethylene), ABS, PP (polypropylene), and PS (polystyrene), and then injection- and extrusion-molded, to thus make it suitable for industrial uses, including interior and exterior construction materials, and also to provide purified urushiol manufactured using the above method. Technical Solution

[7] In order to achieve the above abjects, the present invention provides a method of manufacturing purified urushiol, comprising mixing crude lacquer with ethanol, and then centrifuging the mixture, thus separating an urushiol layer dissolved in ethanol, mixing the urushiol, dissolved in ethanol, with a catalyst, and then conducting hy- drogenation in a hydrogenation reactor, and filtering the hydrogenation product to remove the catalyst and impurities therefrom, and then conducting vacuum drying. As such, the separating the urushiol layer is conducted by mixing crude lacquer and ethanol at a ratio of 1:0.8-1.2 and subjecting the mixture to centrifugation at 3,000-7,000 rpm for 10 min.

[8] The present invention provides purified urushiol for synthetic resin, further comprising distilling the separated urushiol layer under reduced pressure at 40~100°C to thus evaporate water and ethanol and then mixing the dried urushiol with ethanol at a ratio of 1:0.3-1, after the separating the urushiol layer.

[9] The present invention provides the Catalyst, comprising Ni-Al alloy catalyst for the

useful the hydrogenation.

[10] The present invention provides the hydrogenation, comprising at a hydrogen pressure of 30-80 bar, a stirring speed of 200-400 rpm, and 15-25 ⁰ C for 12-36 hours.

[11] In addition, the present invention provides purified urushiol for addition to synthetic resin, manufactured using the above method.

[12]

[13] Hereinafter, a detailed description will be given of the present invention.

[14] In the present invention, lacquer sap, which is native to Korea, China or Japan, may be used without limitation. Crude lacquer is filtered using filter paper to remove impurities therefrom, mixed with ethanol, and then centrifuged. Mixing with ethanol is conducted to separate urushiol from the lacquer sap through centrifugation. Here, in place of ethanol, any organic solvent, including methanol or butanol, may be used. However, methanol is harmful to the human body, undesirably decreasing the workability thereof, and butanol is difficult to subsequently remove due to its high boiling point. Ethanol, having the ability to bind a mixture including rubber and so on, enables efficient centrifugation even in small amounts. Further, unlike other organic solvents, ethanol generates less pollution, and furthermore, has a low boiling point and therefore may be rapidly volatilized at low temperatures in a drying process.

[15] With the aim of sufficiently dissolving urushiol in ethanol for easy centrifugation, it is preferred that crude lacquer and ethanol be mixed at a ratio of 1:0.8-1.2. In the case where the mixing ratio of ethanol is less than 0.8, urushiol may not be sufficiently dissolved. On the other hand, if the mixing ratio exceeds 1.2, the solvent is used in an unnecessarily high amount, undesirably increasing expenses through increased evaporation. When centrifugation is conducted at 3,000-7,000 rpm for 10 min, a solid precipitate, including a rubber or nitrogen compound, settles as a lower layer, and thus it is possible to separate an urushiol layer dissolved in ethanol, as an upper layer, from the lower layer.

[16] Urushiol dissolved in ethanol is mixed with a metal catalyst, and is then subjected to hydrogenation using a hydrogenation reactor. In this case, to rapidly realize hydrogenation, after the separation of the urushiol layer, it is preferred that the separated urushiol layer be distilled under reduced pressure at 40~100°C to thus evaporate water and ethanol, and then that the dried urushiol be mixed with ethanol at a ratio of 1:0.3-1.

[17] In order to easily generate hydrogenation, a catalyst is used in the present invention, and examples thereof include, but are not limited to, metal catalysts, including Ni-Al alloys, Pt, and Pd. Of them, particularly useful is Ni-Al alloy. The urushiol dissolved in ethanol and the catalyst are mixed at a ratio of 1:0.1-0.5, placed in a hydrogenation reactor, and then subjected to hydrogenation under conditions of a hydrogen pressure

of 30-80 bar, a stirring speed of 200-400 rpm, 15-25 ⁰ C, and 12-36 hours. Through the hydrogenation, unsaturated urushiol may be converted into saturated urushiol. Thereafter, the hydrogenation product is filtered to remove the catalyst and impurities therefrom, and is then cooled to 30~40°C.

[18] After the cooling process, purified urushiol in a solid phase may be obtained. The purified urushiol may be ground to thus be applied in a powder state if needed. That is, through the hydrogenation according to the present invention, unsaturated urushiol component in a liquid phase is converted into saturated purified urushiol in a solid phase, which may thus be easily dissolved in an organic solvent. Hence, urushiol thus obtained is mixed with various thermoplastic resins, after which the mixture is subjected to injection- and extrusion-molding.

[19] The purified urushiol according to the present invention is dissolved in benzene, and the properties thereof are analyzed through separation of a white fraction of column chromatography. Through this process, it has been confirmed that saturated urushiol having a melting point of 58.0~60°C is obtained.

[20] The purified urushiol, manufactured using the above method, has a low melting point, and thus it may be subjected to injection-molding. Further, the purified urushiol may be easily dissolved in various organic solvents, and may thus be easily mixed with synthetic resin, including PA (polyamide), PC (polycarbonate), PE (polyethylene), ABS, PP (polypropylene), and PS (polystyrene), therefore realizing various applications in printing and constructing interior and exterior materials. Further, the main component of the lacquer sap functions to exhibit excellent far infrared emissivity, electromagnetic wave-blocking effects and antibacterial activity, thus making it possible to produce environmentally friendly products.

[21]

Advantageous Effects

[22] According to the present invention, the method of manufacturing the purified urushiol enables the conversion of unsaturated urushiol into saturated urushiol through hydrogenation, thus manufacturing purified urushiol which may be easily dissolved in various organic solvents to thus be added to synthetic resin. The purified urushiol manufactured using the above method has a low melting point, and therefore may be easily injection-molded, and may also be easily dissolved in various organic solvents, and therefore may be variously applied to printing or interior and exterior construction materials. Furthermore, the main component of the lacquer sap functions to exhibit excellent far infrared emissivity, electromagnetic wave-blocking effects and antibacterial activity, thus making it possible to produce environmentally friendly products.

Brief Description of the Drawings

[23] FIG.1 is a standard curve of absorbance of saturated urushiol manufactured using the manufacturing method of the present invention. Mode for the Invention

[24] A better understanding of the present invention may be obtained through the follow examples, test examples and tables, which are set forth to illustrate, but are not to be construed as the limit of the present invention.

[25]

[26] Example 1. Manufacture of Purified Urushiol

[27] 1000 g of crude lacquer, native to China, was mixed with 1000 g of ethanol, and then centrifuged at 5,000 rpm for 10 min, thus separating 1800 g of an urushiol layer, dissolved in ethanol, from a pellet precipitate including a rubber and nitrogen compound. The urushiol layer was distilled under reduced pressure at 6O ⁰ C, thus evaporating water and ethanol, after which 520 g of the dried urushiol was mixed with 520 g of ethanol, thereby preparing a mixed urushiol/ethanol solution having a viscosity adjusted to facilitate stirring upon hydrogenation.

[28] 250 ml of the mixed urushiol/ethanol solution was mixed with 30 g of a Ni-Al alloy catalyst and then subjected to hydrogenation in a hydrogen reactor. This reaction was conducted under conditions of a hydrogen pressure of 50 bar, a stirring speed of 300 rpm, 2O ⁰ C, and 24 hours. When hydrogen supply was stopped, and then the hydrogen pressure in the reactor was not decreased, the reaction was judged to be completed.

[29] 250 ml of the resultant product was filtered using a vacuum filter, thus removing impurities including the catalyst. Subsequently, the product was applied to a thickness of 2-3 mm on a wide plate having a size of 200 x 200 mm or more, and was then cooled to 4O ⁰ C or less in a vacuum oven to solidify it, thereby obtaining 120 g of purified urushiol.

[30]

[31] Example 2. Analysis of Component of Purified Urushiol

[32] 25 g of the purified urushiol obtained in Example 1 was dissolved in 200 ml of benzene, and was then purified through 50-200 mesh silica gel column chromatography, thus obtaining 6 g of at least 98% saturated urushiol having a melting point of 58.0~60°C.

[33] 0.05 g of the saturated urushiol was accurately weighed and dissolved in sufficient ethanol to prepare 25 ml of a solution, 10 ml of which was taken and then diluted to 50 ml using ethanol, from which each of 1, 2, 3, 4 and 5 ml was then taken to thus prepare five solution samples. Then, 25 ml of a solution (FeCl 6H O 0.1 g/ethanol 100ml) and

to 100 ml using ethanol, 10 ml of which was then added to each of the five solution samples, after which each solution was diluted to 25 ml using ethanol. Each solution was placed in a quartz cell, the absorbance thereof was measured, and the average value per ml was determined. The standard curve of absorbance of saturated urushiol is depicted (FIG. 1).

[34] The standard curve of absorbance of saturated urushiol may be used to determine the previously unknown content of saturated urushiol in the sample. Specifically, about 0.2 g of a sample was taken from the lacquer sample containing an unknown content of urushiol, dissolved in ethanol, filtered with filter paper, and diluted with 100 ml of ethanol, 1 ml of which was then taken, mixed with 10 ml of the prepared solution, diluted to 25 ml using ethanol, and then measured for absorbance. Comparing this absorbance with the standard curve of absorbance of saturated urushiol, the unknown content of saturated urushiol contained in the sample could be determined.

[35] The urushiol content is calculated according to Equation 1 below:

[36] Equation 1

[37] Saturated Urushiol Content (%) = dxVxlOO WxKxQ98

[38] wherein

[39] d: g/ml of saturated urushiol

[40] V: ml of saturated urushiol of the standard curve using absorbance

[41] W: weight of lacquer sample containing an unknown content of urushiol

[42] K: proportional constant

[43] 0.98: purity of urushiol

[44]

[45] Preparative Example 1. Preparation of MDF Panel using Purified Urushiol

[46] 100 g of the purified urushiol obtained using the method of Example 1 was dissolved in 50 g of ethanol, after which 100 g of this solution was mixed with a melamine resin solution (available from Korea Gravure), thus preparing 1 kg of a mixture solution.

[47] Gravure printing paper, which is paper weighing 80 g/m and printed with a woodgrain pattern through gravure printing, was immersed in the above mixture solution to thus coat both surfaces of the printing paper, and then dried at 12O ⁰ C for 90 sec. The dried printing paper was thermocompressed on an MDF panel at 18O ⁰ C for 45 sec at 25 kg/cm to thus adhere it to the panel, thereby manufacturing an MDF (Medium Density Fiberboard) panel.

[48] Test Example 1. Test of Far Infrared Emissivity

[49] The emissivity of far infrared rays from the MDF panel manufactured in Preparative Example 1 was measured by the Korea Institute of Far Infrared Applied Estimation at the present inventors 'request.

[50] Specifically, the emissivity of the above panel was measured at 37 ⁰ C using an FT- IR spectrometer, and was compared to that of a black body. The results are shown in Table 1 below. As is apparent from Table 1, the far infrared emissivity could be seen to be superior.

[51] [52] Table 1

[53] [54] Test Example 2. Test of Antibacterial Activity [55] The test for antibacterial activity of the MDF panel manufactured in Preparative Example 1 was performed by the Korea Testing and Research Institute for Chemical Industry at the present inventors request. In this case, the test strains were Escherichia CoIi ATCC 8739 and Staphylococcus aureus ATCC 6538. As a coating film and control sample, a sterile polybag for a Stomacher 400 was used.

[56] [57] Table 2

[58] [59] Here, A is the initial bacterial cell number (average) of the control sample, B is the bacterial cell number (average) of the control sample after 24 hours of incubation, and C is the bacterial cell number (average) of the test sample of the present invention after 24 hours of incubation. In addition, an antibacterial value (log(B/C)) is obtained by

subtracting log(C/A) from log(B/A).

[60] As is apparent from Table 2, the panel manufactured using the purified urushiol of the present invention could be seen to exhibit superior antibacterial activity.

[61]

[62] 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

[63] According to the present invention, the method of manufacturing the purified urushiol enables the conversion of unsaturated urushiol into saturated urushiol through hydrogenation, thus manufacturing purified urushiol which may be easily dissolved in various organic solvents to thus be added to synthetic resin. The purified urushiol manufactured using the above method has a low melting point, and therefore may be easily injection-molded, and may also be easily dissolved in various organic solvents, and therefore may be variously applied to printing or interior and exterior construction materials. Furthermore, the main component of the lacquer sap functions to exhibit excellent far infrared emissivity, electromagnetic wave-blocking effects and antibacterial activity, thus making it possible to produce environmentally friendly products.