KR100425774B1 - Method for making a bundle of photocatalyst-coated plastic optical fibers - Google Patents

Abstract

The present invention discloses a method for producing a plastic optical fiber bundle coated with a photocatalyst. The method of manufacturing a photocatalyst coated plastic optical fiber bundle according to the present invention comprises the steps of preparing a solvent having a functional group of CH ₃ CR for dissolving the shell of the plastic optical fiber and not damaging the core of the plastic optical fiber; Immersing in a solvent by an outer length of the plastic optical fiber to be removed; Washing the core of the removed plastic optical fiber with distilled water; Coating the photocatalyst on the core; Drying the photocatalyst coated plastic optical fiber at a temperature of 80 degrees Celsius or less; Repeatedly forming the plurality of plastic optical fibers made by repeatedly performing the above steps; Polishing end surfaces of the plurality of plastic optical fibers. According to the present invention, according to the manufacturing method of the photocatalyst-coated plastic optical fiber bundle can be easily removed the outer sheath of the plastic optical fiber can be produced in a bundle of a plurality of plastic optical fibers from which the outer shell is removed, the price is very cheap and easy to handle There is an effect that one plastic optical fiber can be applied to a photochemical reaction.

Description

METHODS FOR MAKING A BUNDLE OF PHOTOCATALYST-COATED PLASTIC OPTICAL FIBERS}

The present invention relates to a method for manufacturing optical fiber coated with a photocatalyst, and more particularly, to a method for manufacturing a plastic optical fiber bundle by removing the envelope of a polymer optical fiber (POF) and photocatalyst coating.

As is well known, the band energy inherent in semiconductor photocatalytic materials—conduction bands (E _cb ) with no electrons filled in them and atoms called valence bands (E _vb ) filled with electrons. There is a molecular orbital consisting of linear combinations of orbits. Thus, there is a forbidden space between the two bands that cannot be occupied by the electrons. This is called the band energy (E _g ), and its size corresponds to E _cb -E _vb . - or more electron (e ^-) in the receiving E _vb light energy after the here (Excitation) generated electron (e ^-) found in the original in the design of the hole (h ⁺⁾ pairs are used to advantage photochemical system Reactor It enables the transmission of light that can solve the constraint of.

The conversion of light energy into chemical energy or electrical energy through the above-described photochemical reaction process reduces or oxidizes the generated electrons / holes adsorbed to the photocatalyst or in the diffusion layer, or By generating a current. This can be used for environmental purification to decompose organic substances in the surroundings, as well as for hydrolysis hydrogen production and solar cells. The biggest problem to be solved here is to develop a stable photocatalyst that can utilize visible light, which takes up more than 44% of sunlight, and thus the theoretical maximum photovoltaic conversion efficiency of 42% (24% for hydrolysis hydrogen production). In the near future, environmentally friendly and economical environmental clean-up and the production of alternative / clean energy can contribute tremendously to human society.

Recently, there is a limitation in the shape and material of the reactor due to the use of the conventional cylindrical lamps in order to solve this problem, optical fibers are used in the photochemical reactor. The optical fiber absorbs light by the continuous reflection and refraction of the light irradiated from one end of the optical fiber by removing all the skins other than the core and coating the photocatalyst on the surface of the core, so that a photochemical reaction occurs that can decompose the surrounding material. Can be. Accordingly, the type and material of the reactor can be varied, and the light can be transmitted, so that the external natural light can be used, and the reactor and the light source can be separated, thereby enabling environmental purification in hazardous areas, isolated spaces, and underground commercial facilities. Lose. In particular, in the case of a slurry-type system for water treatment, the penetration of light is about 0.2 mm, and the configuration of the system is limited. However, when using an optical fiber, the volume reaction can be easily achieved by utilizing a large number of optical fibers.

As such, studies on using optical fibers for photochemical reactions are being actively conducted. The optical fibers used for photochemical reactions are quartz optical fibers (QOF), in which the core of the outer core is coated with quartz. Quartz fiber is expensive, but it is used as optical fiber for photochemical reaction because of its excellent light transmission efficiency. The technology using quartz fiber was first proposed in 1977 by Professor Ollis of the United States (AICHE J., 1977, 23, 415). Since then, the technology of quartz fiber (QOF) has been developed by Hoffmann, California Institute of Technology. It is continuously studied by Professor Hoffman and published in the paper (Environ Sci. Tech., 1995, 29, 2974) and the like, and related technical contents are disclosed in US Pat. No. 5,875,384. Meanwhile, a method of manufacturing a quartz optical fiber bundle in relation to a vapor volatile organic compound is disclosed in Korean Laid-Open Patent Publication No. 2000-17691.

However, the quartz optical fiber conventionally used for environmental purification has a disadvantage that it is very difficult to handle because it is very expensive and easily broken as described above. Accordingly, the quartz optical fiber used for environmental purification is limitedly used only for experiment and research.

The present invention intends to apply a plastic optical fiber instead of a quartz optical fiber as a light transmission medium for the photochemical reaction. Plastic optical fiber was first developed by DuPont in 1964 and then started production in 1983 by Mitsubishi Rayon. Plastic optical fiber has the advantages of low cost (30% of the high purity optical quartz cost, production cost about 0.12 ＄ / m) and very flexible and tough handling even when the outer skin is removed. On the other hand, plastic optical fiber has a large disadvantage that the loss ratio of near-ultraviolet light is about 10 times larger than that of quartz optical fiber and cannot be heat-treated. In addition, there is a disadvantage that it is altered by ultraviolet light having a wavelength of 250nm or less.

Although plastic optical fibers have the disadvantages described above, they can be significantly compensated by changes in bundle manufacturing processes such as the length of the stripped part and the diameter of the core, room temperature drying, etc. There are solutions such as the wavelength is mainly 388nm and sunlight does not exist in the 250nm wavelength light. In order to use the plastic optical fiber in the photochemical reaction as described above, development of a method of easily removing the outer surface of the plastic optical fiber should be preceded.

Accordingly, the present invention is to provide a method for producing a photocatalyst-coated plastic optical fiber bundle that can easily remove the outer surface of the plastic optical fiber and to produce a plurality of plastic optical fiber bundles from which the outer skin is removed.

Another object of the present invention is to provide a method for producing a photocatalyst-coated plastic optical fiber bundle which can be applied to a photochemical reaction of a plastic fiber which is very inexpensive and easy to handle.

1 is a conceptual diagram showing the principle of operation of a plastic optical fiber coated with a photocatalyst on the core according to the present invention,

Figure 2 is a schematic view showing a configuration in which a plurality of plastic optical fiber coated with a photocatalyst according to the present invention,

3 is a flow chart of a method for manufacturing a photocatalyst-coated plastic optical fiber bundle according to the present invention.

♣ Explanation of symbols for main part of drawing ♣

1: jacket 2: core

3: one end of optical fiber 5: photocatalyst

10: plastic optical fiber 20: holder

30: Bundle L: Light

L1: refractive light L2: reflected light

In order to achieve the above object, the manufacturing method of the photocatalyst-coated plastic optical fiber bundle according to the present invention has a functional group of CH ₃ CR for dissolving the outer surface of the plastic optical fiber, and prepares a solvent that does not damage the core of the plastic optical fiber. Steps; Immersing in a solvent by an outer length of the plastic optical fiber to be removed; Washing the core of the removed plastic optical fiber with distilled water; Coating the photocatalyst on the core; Drying the photocatalyst coated plastic optical fiber at a temperature of 80 degrees Celsius or less; Repeatedly forming the plurality of plastic optical fibers made by repeatedly performing the above steps; Polishing end surfaces of the plurality of plastic optical fibers.

Hereinafter, with reference to the accompanying drawings, an embodiment of a method for producing a photocatalyst-coated plastic optical fiber bundle according to the present invention will be described in detail.

First, with reference to Figure 1 will be described the principle of the action of a plastic optical fiber coated with a photocatalyst in the core according to the present invention. Plastic optical fiber 10 is composed of a fluorine-substituted polymethyl methacrylate (F-PMMA: Fluoro-Polymethyl Methacrylate) shell (1) and a polymethyl methacrylate (PMMA) core (2). Light L is incident from the end 3 of the optical fiber, and the light incident on the optical fiber is transmitted to the other end 4 while repeating reflection and refraction. Refracted light L1, which is light refracted in this process and emitted to the outside of the core 2, is absorbed by the photocatalyst 5 coated on the surface of the core to activate the photocatalyst 5, and the remaining light is reflected light L2. Will continue to be sent. The photocatalyst 5 activated by the refracted light L1 decomposes and removes the toxic organic substances S around the photocatalyst.

Next, FIG. 2 shows a configuration in which a plurality of plastic optical fibers coated with a photocatalyst on a core are formed according to the present invention. As shown in FIG. 1, when a plurality of photocatalyst-coated optical fibers are made, the holder 20 is formed into a bundle 30. The diagram in the circle of FIG. 2 shows that a plurality of plastic optical fibers are formed in a bundle.

Hereinafter, an embodiment of a manufacturing method of a plastic optical fiber bundle coated with a photocatalyst according to the present invention will be described.

First prepare a solvent for removing the outer shell of the plastic optical fiber in the preparation step (S10). In general, the problem of how far the polymer material dissolves is very difficult to confirm theoretically, as in the case of small molecules. It is known that this is because the polymer material is very large, multi-molecular, and also has a high viscosity and influence of the crystal region. However, based on various experiences, similar chemical structures are more likely to be used, and similar solubility parameters (SP) are well dissolved. This phenomenon can be confirmed by the following equations (1) and (2).

Where H is enthalpy, v is volume fraction, SP is solubility parameter, 1 is solvent, and 2 is polymer.

ΔG = ΔH-TΔS

Where G is Gibbs free energy, T is temperature, and S is entropy.

The above phenomena are ΔH> TΔS when (SP ₁ -SP ₂ ) is very large in Equations 1 and ₂ , that is, ΔG> 0, and ΔH <TΔS when (SP ₁ -SP ₂ ) are similar. This is because ΔG <0.

However, this is not always the case and is known to be affected by interactions between other solvents and polymers. As a result of the experiment for selecting a solvent for the present invention, acetone (SP = 9.71), acetonitrile (SP = 12.10), and acetylacetone were removed from the plastic optical fiber, but other n-hexane (SP = 7.24) was removed. , Ethyl ether (SP = 7.50), carbon tetrachloride (SP = 8.58), toluene (SP = 8.93), benzene (SP = 9.15), n-butanol (SP = 11.40), ethyl alcohol (SP = 12.70), methyl Alcohol (SP = 14.50), nitrobenzene, and water (SP = 23.40) did not remove the plastic fiber shell. Thus, experiments have shown that CH ₃ CR (R is a polar element such as O or N) is commonly present in a solvent in which the outer shell of the plastic optical fiber is dissolved. However, the conditions of use of these solvents should only remove the outer sheath of the plastic optical fiber, and should not damage the core to reduce the light transmission capability of the plastic optical fiber.

In the present invention, it is not possible to use the fire or striper used in the quartz optical fiber to remove the shell of the plastic optical fiber. If the fire is used to remove the shell, not only the shell but also the core is burned, and if the striper is used, the core is also damaged.

In the next step, it is immersed by the length of the outer skin to remove the plastic optical fiber in the acetone selected by the step (S10) (S20). Immersion time, the most suitable desorption time, was determined to be 3 minutes by scanning electron microscopy (SEM) measurements taken hourly during soaking. After immersing the plastic optical fiber for a length of 3 minutes, the plastic optical fiber is washed three to four times with secondary distilled water (Milli-Q, 18 kPa), which is drawn out from acetone (S30).

Next, the core of the plastic optical fiber from which the outer skin is removed is coated with a photocatalyst (S40). Coating methods of the core can be a variety of methods. First, the outer skinned core is coated with 5 wt% TiO ₂ powder (P25 from Degussa GmbH) and then immersed in a solution dispersed by sonication and stirring. Second, in order to coat F4-AP (Showa Denko Co., Ltd.) powder of TiO ₂ coated on apatite on a plastic optical fiber, the coating is performed by mixing a binding additive since it is not simply mixed with a solvent. As the binding additive, for example, an alkoxysilane having stability in the condensation reaction of Si-C bond is used as an inorganic backbone material in the case of coating using the sol-gel method. For example, the molar ratio of ethyl alcohol (Ethylalcohol) and tetraethyl orthosilicate (TEOS) is about 10: 1, and the mixture is sufficiently stirred at room temperature. This ratio can be controlled by the allowable drying time and the strength of the required bonding force. After adding F4-AP powder to a desired weight ratio, the mixed solution was stirred at room temperature for 24 hours, and the plastic optical fiber was immersed in this solution. Third, the plastic optical fiber is coated by spraying. A water dispersion paint (Marutake, Japan) having a photocatalytic content of 30% by weight and a primer for improving the binding strength to the substrate are mixed in a ratio of 1: 1 to 1: 2 by weight, and the total photocatalyst content is 20 to 30%. Be sure to It is coated with a compressor with a pressure of 5-10 kgf / cm ² and a spray gun with a nozzle of 0.3-0.4 mm diameter by 10-30 g / m ² .

In the next step, the plastic film coated with a photocatalyst is dried (S50). The photocatalyst coated plastic optical fiber is dried at a temperature of less than 80 degrees Celsius for approximately 24 hours to prevent cracking. In the case of quartz optical fiber, the heat treatment process is necessarily performed, but the plastic optical fiber does not undergo any heat treatment process because the plastic optical fiber is melted if the plastic optical fiber is heat treated.

The execution of the above steps yields a plastic optical fiber coated with one photocatalyst. Therefore, the steps S10 to S50 are repeatedly executed as many new plastic optical fibers as necessary to form the bundle of plastic optical fibers (S60). Each of the optical fibers produced as described above is bundled in plural as desired. The bundle is made using a portion of which the outer shell is not removed other than the portion of the outer shell (S70). Insert the portion of the optical fiber that is not removed in the hole of 5 ~ 10mm formed in the holder 20 made of stainless steel or Teflon, and put epoxy to dry for 10 hours to produce a bundle. As described above, after the plurality of plastic optical fibers are manufactured in bundles, the end surfaces of the plurality of plastic optical fibers are finally polished (S80). Polishing is to increase the light transmission efficiency of the plastic optical fiber and the inclination and irregularities of the end surface of the plastic optical fiber bundle are removed by the polishing.

As described above, the embodiments of the present invention are described, but the protection scope of the present invention is not limited to the above embodiments, and specific materials and numerical values shown in the above embodiments are exemplified in the present invention. In addition to the embodiments described above, various modifications are possible within the scope of the claims.

As described above, according to the manufacturing method of the plastic optical fiber bundle coated with the photocatalyst according to the present invention, the outer sheath of the plastic optical fiber can be easily removed and a plurality of plastic optical fiber bundles from which the outer skin is removed can be manufactured, and the price is very low and the handling is possible. This easy plastic optical fiber has an effect that can be applied to the photochemical reaction. In addition, it is possible to overcome the restrictions on the material shape of the reactor to be considered when irradiating light from outside the reactor, and when coated on a plane, the area photochemical reaction can be distributed to the volumetric reaction by dispersing and distributing the plastic optical fiber into the reactor volume. There is an effect that can reduce the constraint of the transmission. In addition, it is also possible to apply to the commercial effect of the indoor air purification decorative tools coated with a transparent photocatalyst by applying the decorative effect, which is the main role of the optical fiber.

Claims (7)

Preparing a solvent having a functional group of CH ₃ CR in which R is a polar element so as to dissolve the outer surface of the plastic optical fiber and not damaging the core of the plastic optical fiber; Immersing in the solvent by the length of the outer skin to remove the plastic optical fiber; Washing the core of the plastic optical fiber whose shell has been removed with distilled water; Coating a photocatalyst on the core; Drying the photocatalyst coated plastic optical fiber at a temperature of 80 degrees Celsius or less; Repeatedly forming the plurality of plastic optical fibers made by repeatedly performing the above steps; A method of manufacturing a photocatalyst-coated plastic optical fiber bundle consisting of polishing the end surfaces of the plurality of plastic optical fibers. The method of claim 1, wherein the solvent is acetone and the photocatalyst-coated plastic optical fiber bundle is immersed in the acetone for 3 minutes. The method according to claim 1 or 2, wherein the coating of the photocatalyst on the core is performed by immersing the core in a solution in which TiO ₂ powder is dispersed by mixing with sound waves. The method of claim 1 or 2, wherein the coating of the photocatalyst on the core is performed by mixing TiO ₂ powder coated on the apatite with a solution containing a binding additive and sufficiently stirring the mixture at room temperature, thereby immersing the core in the solution. Method for producing a plastic optical fiber bundle coated with a photocatalyst. 5. The method of claim 4, wherein the binding additive is an alkoxysilane. 6. The method of claim 1 or 2, wherein the coating of the photocatalyst on the core comprises mixing a water-dispersion paint having a photocatalytic content of 30 wt% with a primer for improving the binding force to the substrate in a predetermined weight ratio, and 5 to 10 kgf. A method of manufacturing a photocatalyst-coated plastic optical fiber bundle coated with a compressor having a pressure of / cm ² and a spray gun having a nozzle of 0.3 to 0.4 mm diameter by 10 to 30 g / m ² . The method of claim 6, wherein the weight ratio is in a ratio of 1: 1 to 1: 2.