JP2002212510A - Trielement curing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalyst coating in which a photocatalyst reaction is quickly and strongly caused to degrade pollutants in the environment. SOLUTION: The photocatalyst coating contains titanium oxide, silicon oxide and silicon oxide as the main components of a trielement curing agent, and is cured at ordinary temperature. Since the photocatalyst coating responds to ultraviolet light and visible light to accelerate electrons, a time until exciting the electrons is shortened. When the electrons of the photocatalyst are excited in a short time, the deterioration of electric charge separation can be minimized even under a condition that a large quantity of ultraviolet light is irradiated. Since the copper oxide is compounded, the efficiency of the charge separation is improved, and the recombination of electron holes with electrons produced in the photocatalyst titanium oxide can be prevented to prevent the deterioration of the reaction efficiency. The organic substance-degrading function of the photocatalyst coating is largely improved in comparison with conventional photocatalyst coatings due to these composite factors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold-setting paint which exhibits its characteristics in environmental purification.

[0002]

2. Description of the Related Art Conventionally, photocatalytic paints which contain titanium oxide and cure at room temperature have been sold. However, these photocatalytic paints have the following disadvantages. Conventional photocatalytic coatings form a hydrophilic coating film and are easily compatible with water. When they come into contact with water, they hydrolyze and peel off in a short time. When these paints are applied to porous objects (concrete, wood) or fibers, the attached water penetrates and the inside becomes wet. In conventional photocatalytic paints, it takes a long time from the irradiation of a coating film with ultraviolet rays to the start of a reaction, so that even if a large amount of ultraviolet rays are irradiated, most of the photocatalytic coating material cannot be used for the reaction. As a result, the quantum efficiency of the photocatalytic reaction decreases as more ultraviolet rays are irradiated, and the oxidative decomposition function cannot be sufficiently exhibited. In a conventional photocatalytic paint film, some of the electrons and holes generated inside the photocatalytic titanium oxide recombine. As a result, electrons and holes involved in the reaction diffused to the surface were lost, and the reaction efficiency was reduced.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photocatalytic paint which has a fast photocatalytic reaction and which strongly occurs to decompose environmental pollutants.

[0004]

SUMMARY OF THE INVENTION The present invention is a photocatalytic paint which contains fine powder of three elements, titanium oxide, silicon oxide and copper oxide, as a main component and can be cured at room temperature.

[0005]

The present invention will be described below with reference to examples. Figure 1
FIG. 3 is a view showing the transparency and water resistance of a sample obtained by applying a three-element curing agent according to the present invention to glass. FIG. 2 is a diagram showing the results of an antibacterial test on a sample coated with a three-element curing agent according to the present invention. FIG. 3 is a view showing a function of a test cloth impregnated with a three-element hardener according to the present invention to decompose a chemical substance.

(Embodiment) A three-element curing agent according to the present invention is used by mixing three kinds of solvents, A liquid, B liquid and C liquid, in which respective elements are dispersed, and applying the mixture with a brush or a spray machine. I do.

(Mechanism and components) In this embodiment, the three-element curing agent is a solution A in which titanium oxide, silicon oxide and a silane coupling agent are dispersed, a solution B in which polyalkylsiloxane and copper oxide are dispersed, and A mixture of solution C in which methylmethoxysiloxane is dissolved in isopropyl alcohol is used, and Table 1 shows examples of the formulation.

[0008]

[Table 1]

(Physical Properties of Coating Film) The three-element curing agent according to the present invention forms a colorless and transparent coating film by mixing three liquids, applying the mixture to glass, and drying at room temperature. Coating is 20 after application
After 3 hours, the pencil hardness becomes 5H after 6 hours and 6 hours after 20 hours.
Hardens to H. The contact angle between the coating film and water adhering to the surface is 6
5 °, which is in the hydrophobic range. (Kyowa contact angle meter (CA-A type) three-point average)

(Water resistance of the coating film) The glass coated with the three-element curing agent according to the present invention was immersed in water, and the hardness of the coating film was measured after 2400 hours. As a result, the pencil hardness was 5H.
The coating has excellent water resistance and hardly decreases in hardness due to hydrolysis.

(Method of Demonstrating Effectiveness by Photocatalytic Reaction) When the photocatalytic titanium oxide is irradiated with light having a wavelength corresponding to the band gap, electrons in the valence band are excited and rise to the conduction band. As a result, the holes generated in the valence band react with the adsorbed water to cause an oxidizing action, and the electrons react with the surface adsorbed oxygen to cause a reducing action. The oxidizing action sterilizes microorganisms attached to the surface and decomposes organic matter to purify the environment. The bactericidal and antibacterial properties of the three-element hardener and the decomposing ability of organic substances according to the present invention
Proven below by antibacterial test and discoloration test.

(Method of Antibacterial Test) A sample in which the three-element curing agent according to the present invention was applied to plywood of 4 cm square was grounded on an agar medium dispensed into a petri dish having a diameter of 15 cm. The samples were sprayed and inoculated with spore dispersions of the six test bacteria shown in Table 2 and inoculated with JI.
Cultivation was performed for one month while irradiating a 27-watt fluorescent light from a distance of 50 cm (ultraviolet light intensity 1 μw) under culture conditions of SZ 2911 standard.

[0013]

[Table 2]

(Results of Antibacterial Test) As shown in FIG. 2, the inoculated test bacteria propagated on the agar medium, but no bacteria propagated on the sample. This is a result of the oxidative power of OH radicals generated by the photocatalytic reaction occurring on the surface of the sample killing and decomposing the test bacteria. It has been proved that microorganisms can be killed and propagation of bacteria can be suppressed for a long time even with an ultraviolet light intensity (1 μw) of such a degree as existing in a room such as a fluorescent lamp.

(Chemical substance decomposing ability) A test cloth is prepared by impregnating a three-element hardener (KBL Coat 3E) according to the present invention into a white cotton cloth and drying, and then applying a liquid in which the reagents shown in Table 3 are dissolved. did. (The reagents in Table 3 discolor yellow when thermally decomposed.) When each test cloth was irradiated with sunlight (ultraviolet light intensity 2,000 μw), all the test cloths began to discolor yellow after 10 minutes and gradually turned deeper. This discoloration suggests that the reagent was developed as a result of decomposition. Then, all the discoloration occurred simultaneously regardless of the heat resistance of the reagent applied to each test cloth.

[0016]

[Table 3]

(Decomposition Power and Copper Oxide) CK-507 obtained by removing copper oxide from KBL coat 3E as a target of the discoloration test,
A solution in which a reagent (TBZ) was dissolved was applied to a cloth coated with G-CU excluding the photocatalyst and an untreated cotton cloth, respectively, and irradiated with sunlight. Table 4 shows the degree and speed of yellow discoloration of the test cloth.
Judgment was made based on the following criteria. As a result, as shown in Table 5, CK-5
07 applied to the test cloth began to change color after 80 minutes.
-CU and the untreated test cloth did not discolor even after 24 hours. (Table 5) In this test, only the test cloth coated with CK-507 containing the photocatalyst discolored, but did not contain copper oxide.
It took 12 to 30 times as long to reach the same degree of discoloration as E. (Variation of 5 points of test cloth)

[0018]

[Table 4]

[0019]

[Table 5]

(Copper and light absorption) Copper has a wavelength of 350 to 600
The light of nm is reflected, absorbed, and transmitted at the ratio shown in Table 6. When light enters copper, an oscillating electric field of light is created. The electric field accelerates the free electrons in the copper to be in an excited state and collectively rise to a conduction band having a high potential. In the coating film of the three-element curing agent according to the present invention, the excited free electrons (waves) spread over the entire coating film and interfere with and accelerate the electrons of the second metal (titanium oxide). The accelerated electrons are reduced in time until excitation, so that when irradiated with ultraviolet light, they are excited in a short time and a photocatalytic reaction occurs. The three-element curing agent according to the present invention does not respond to visible light because it uses anatase-type titanium oxide, but the use of visible light by adding copper oxide reduces the time until a photocatalytic reaction occurs. It could be significantly reduced.

[0021]

[Table 6]

(Prevention of Reduction of Quantum Efficiency) The quantum efficiency of the reaction of the photocatalytic titanium oxide decreases at the ratio shown in Table 7 as the intensity of the ultraviolet light increases. Even if a large amount of ultraviolet light is applied to a conventional photocatalytic coating film, it takes too much time to excite electrons, so that much of the film could not be used for the reaction. The coating of the three-element curing agent according to the present invention responds to light of a wide range of wavelengths and can rapidly accelerate and excite a large number of electrons in the coating. As a result, in the discoloration test, even under the condition that the irradiation amount of the ultraviolet ray is large, the decrease in the quantum efficiency was minimized and a strong oxidative decomposition power was developed in a short time.

[0023]

[Table 7]

(Charge Separation) The copper oxide is present in the coating film of the three-element curing agent according to the present invention, thereby improving the charge separation efficiency. When charge separation improves, recombination of electrons and holes generated inside the photocatalytic titanium oxide can be prevented, and most of them can participate in the photocatalytic reaction, thereby preventing a reduction in reaction efficiency. As a result, in the coating film of the three-element curing agent according to the present invention, the redox action by the photocatalytic reaction was strongly exhibited in the discoloration test, and the reagent was decomposed in a short time.

(Advantages of Hydrophobic Coating Film) The physical properties of the coating film formed by the three-element curing agent according to the present invention are hydrophobic, and the hydrophobic coating film efficiently converts OH radicals generated on the surface of titanium oxide. It decomposes organic substances that are well diffused on the surface.

(Applied to places where filth adheres heavily) The three-element curing agent according to the present invention cannot be purified due to insufficient adhesion of the filth even if the irradiation amount of ultraviolet rays is large, because there is not enough time to decompose the filth. If you use it for the part, you can get results.

(Purification around water) Since the three-element curing agent according to the present invention has impaired water resistance, it is applied to prevention of contamination of underwater structures, sterilization of microorganisms, fungi, bacteria and viruses in water and decomposition of impurities. be able to.

(Ship bottom paint) The three-element curing agent according to the present invention can be applied to the bottom of a ship and used for preventing adhesion of microorganisms (slime bacteria, algae, shellfish). The present invention promotes the reaction by using visible light that enters deeper into water than ultraviolet light, and is therefore suitable for use in water. The physical properties of the coating are hydrophobic and have little resistance to water, so it does not hinder the ship's navigability.

[0029]

As described above, when the three-element curing agent according to the present invention is applied, a colorless, transparent and hard coating film is formed to protect the object. When light is applied to the coating film, a strong photocatalytic reaction occurs in a short time, and microorganisms, chemical substances, and the like that come into contact with the surface are decomposed. As a result, substances that pollute the environment are reduced, resulting in a clean environment. It is expected to be used in various fields in the future.

[Brief description of the drawings]

FIG. 1 is a diagram in which a three-element curing agent according to the present invention is applied to glass.

FIG. 2 is a diagram after one month of culture in which an antibacterial test was performed using a plywood coated with a three-element hardener according to the present invention as a sample.

FIG. 3 is a diagram in which a reagent applied to a cotton cloth impregnated with a three-element curing agent according to the present invention has been decomposed and turned yellow.

[Explanation of symbols]

 Reference Signs List 1 glass coated with three-element hardener 2 pencil hardness of coating film 3 agar medium 4 petri dish 5 inoculated bacteria 6 sample 7 cotton cloth coated with KBL coat 3E 8 cotton cloth coated with KBL coat CK507 9 cotton cloth coated with KBL coat GCu Coated cotton cloth 10 Untreated cotton cloth

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[Procedure amendment]

[Submission date] August 23, 2001 (2001.8.2
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

(Copper and light absorption) Copper has a wavelength of 350 to 600
The light of nm is reflected at the ratio shown in Table 6, and the others are absorbed and transmitted. When light enters copper, an oscillating electric field of light is created. The electric field accelerates the free electrons in the copper to be in an excited state and collectively rise to a conduction band having a high potential. Excited free electrons (waves) in the coating of the three-element hardener according to the invention
Spreads throughout the coating film, accelerating the electrons of the titanium oxide .
The accelerated electrons are reduced in time until excitation, so that when irradiated with ultraviolet light, they are excited in a short time and a photocatalytic reaction occurs. Although the three-element curing agent according to the present invention uses anatase-type titanium oxide, it does not respond to visible light,
By incorporating copper oxide, visible light was utilized and the time required for the photocatalytic reaction to occur was significantly reduced.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/16 C09D 5/16 7/12 7/12 // C03C 17/25 C03C 17/25 A F term (Reference) 4G059 AA01 AC22 EA01 EA04 EA05 EB05 EB06 4G069 AA03 AA08 BA02A BA02B BA04A BA04B BA48A BB02A BB04A BB04B BC16A BC31A BC31B BC51A BC60A CD10 DA05 EA11 ED04 FA03 FB23 401 BC01A02 PA18 PB14

Claims (2)

[Claims] 1. A photocatalytic paint containing titanium oxide, silicon oxide and copper oxide as main components and curing at room temperature. 2. A photocatalytic paint in which titanium oxide and metal powder (zirconium, tungsten, aluminum, zinc, etc.) are dispersed.