Hydrophobic material, method for producing hydrophobic coating material, method for producing hydrophobic concrete, method for producing mildew-proof material, method for producing rust-proof material, and hydrophobic material

Abstract

The present invention provides a hydrophobic material using rice husk as a waste material, a method for producing the hydrophobic material, a method for producing a hydrophobic coating material containing the hydrophobic material, a method for producing a hydrophobic concrete containing the hydrophobic material, and a method for preventing mildew using the hydrophobic material. And a rust prevention method using the hydrophobic material. A method for producing a hydrophobic material, etc., comprising a step for mixing fired rice husks with silicone oil; and a step for obtaining a hydrophobic fired product by firing the mixture of the rice husk and the silicone oil.

Description

Technical Field

[0001] The present invention relates to a method for producing a hydrophobic material, a method for producing a hydrophobic coating, a method for producing hydrophobic concrete, a mildew-proof method, a rust-proof method and a hydrophobic material. Background Art

[0002] A liquid hydrophobic agent containing silicone oil is known as described in Patent Document 1. The hydrophobic material of Patent Document 1 is a liquid hydrophobic agent composition containing a paraffin oil or a low molecular weight hydrocarbon resin having a separation index with respect to silicone oil of 0.4 or less and silicone oil.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 61-115988 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In the case of a hydrophobic agent mainly composed of a purified compound as in Patent Document 1, the production of the raw material of the hydrophobic composition costs money, and there is a tendency for the cost of the hydrophobic composition to increase. If waste materials are used as the raw material of the hydrophobic material, the cost required for the production of the hydrophobic material can be reduced, but there is no such disclosure in Reference 1.

[0008] The object of the present invention is to provide a hydrophobic material using rice husks as waste materials and a method for producing the hydrophobic material, a method for producing a hydrophobic paint containing the hydrophobic material, a method for producing hydrophobic concrete containing the hydrophobic material, a mildew prevention method using the hydrophobic material, and a rust prevention method using the hydrophobic material.

[0009] Solutions for solving the above technical problems

[0010] The above-mentioned technical problems are solved by a method for producing a hydrophobic material, which comprises: a step of mixing fired rice husks with silicone oil; and a step of firing the mixture of rice husks and silicone oil to obtain a hydrophobic fired product.

[0011] The above technical problems are solved by a method for producing a hydrophobic material, which comprises: a step of burning rice husks; a step of mixing the burned rice husks with silicone oil; and a step of burning the mixture of rice husks and silicone oil to obtain a hydrophobic burned product.

[0012] The above technical problem is solved by the following method for producing a hydrophobic coating, which comprises: a step of mixing the hydrophobic material with the coating.

[0013] The above-mentioned technical problems are solved by a method for producing hydrophobic concrete, which comprises a step of mixing the hydrophobic material with a concrete composition.

[0014] The above technical problem is solved by the following anti-mildew method, which applies the hydrophobic coating to a structure to prevent mildew in the structure.

[0015] The above technical problem is solved by the following rust prevention method, which applies the hydrophobic coating to the metal material to prevent rust.

[0016] The above technical problems are solved by the following hydrophobic material, which contains the burnt material of rice husk and silicone oil.

[0017] In the method for producing the hydrophobic material, the temperature when the mixture is fired can be set to 500 to 900° C. In addition, in the method for producing the hydrophobic coating, the amount of the hydrophobic material can be set to 0.5 to 6% by mass of the mass of the coating, based on the mass of the coating before the hydrophobic material is mixed. In addition, in the method for producing the hydrophobic concrete, the hydrophobic material can be set to 0.5 to 6% by mass of the mass of the cement mixed in the concrete composition.

[0018] Effects of the Invention

[0019] According to the present invention, there can be provided a hydrophobic material using rice husks as waste materials, a method for producing the hydrophobic material, a method for producing a hydrophobic paint containing the hydrophobic material, a method for producing a hydrophobic concrete containing the hydrophobic material, a mildew prevention method using the hydrophobic material, and a rust prevention method using the hydrophobic material. DETAILED DESCRIPTION

[0020] Hereinafter, preferred embodiments of the present invention will be described. The embodiments described below are merely limited examples of the embodiments of the present invention, and the technical scope of the present invention is not limited to the exemplified embodiments.

[0021] The method for producing a water-repellent material according to the present embodiment includes: a step of burning rice husks; a step of mixing the burned rice husks with silicone oil; and a step of burning the mixture of rice husks and silicone oil to obtain a water-repellent burned product.

[0022] Rice husk is the outer skin of rice grains. As the rice husk, from the perspective of cost, it is preferable to use the material discharged as industrial waste when the outer skin is removed from rice. Rice is a silicic acid plant and actively absorbs silicic acid from the soil. The absorbed silicic acid is accumulated in high concentration in the rice husk.

[0023] In the process of burning rice husks, the rice husks are burned by an appropriate method. When burning rice husks, it is preferably heated to the extent that the color of the rice husks turns black under the condition of supplying oxygen and completely burning. The temperature when burning rice husks is preferably set to 500-900°C, for example. By burning rice husks, a black burnt material with a high content of silicon dioxide (SiO2) can be obtained. The content of silicon dioxide contained in the black burnt material is, for example, 90-98% by mass. In addition, by burning rice husks, the rice husks are porous. Silicon dioxide has excellent chemical resistance and heat resistance and is not easy to deteriorate. Therefore, the material obtained by mixing with silicone oil and burning, for example, is not easily affected by acid rain, chemicals, etc., and becomes a hydrophobic material with excellent durability. In this way, by making silicone oil supported on the burnt material of rice husks with excellent durability as the main body of silicon dioxide, the silicone oil itself becomes difficult to decompose or deteriorate, and the hydrophobic effect is sustained for a long time.

[0024] In the step of mixing the burned rice husk and the silicone oil, the burned rice husk and the silicone oil are preferably mixed at a ratio of 4 to 200 parts by mass of silicone oil to 100 parts by mass of the burned rice husk. The silicone oil is more preferably 4 to 50 parts by mass, and more preferably 4 to 15 parts by mass. In this step, the silicone oil is carried on the rice husk. When the burned rice husk containing silicon dioxide as the main component is mixed with the silicone oil, it blends well and can be mixed uniformly.

[0025] The silicone oil can preferably be a commercial product having a contact angle with a water drop of 40° or more obtained by the sessile drop method according to JIS R3257:1999. The contact angle is more preferably 90° or more. The upper limit of the contact angle is not particularly limited, but is, for example, 160° or less or 150° or less. As the silicone oil, for example, a silicone oil having a polymer having a siloxane bond in the main chain as an active ingredient can be cited.

[0026] In the step of burning the mixture of rice husks and silicone oil to obtain a hydrophobic burnt product, the mixture of the burnt product of rice husks and silicone oil is burned. When burning the rice husks, it is preferred to heat the rice husks to a degree that the color of the rice husks turns white under the condition of supplying oxygen to cause complete combustion. The temperature when burning the rice husks is preferably set to 500 to 900° C., for example.

[0027] The white fired product obtained by the above method has hydrophobicity. For example, if it is mixed into a concrete composition, a hydrophobic concrete molded product can be obtained. In addition, if it is mixed into a paint, a hydrophobic paint can be obtained.

[0028] The above-mentioned concrete molding having hydrophobicity itself has hydrophobicity. Therefore, if the concrete molding is used to construct an outdoor structure such as an outer wall, water can be prevented from penetrating into the interior of the concrete molding, and the mold of the structure can be effectively prevented. In addition, if the concrete molding has steel bars, corrosion of the steel bars can be effectively prevented. Examples of the structure include outer walls, steps, flower beds, gate posts, slopes, inner walls or bases of tunnels, etc.

[0029] The composition of the concrete composition is not particularly limited as long as it contains cement, aggregate and water. A surfactant may be added to facilitate mixing of the hydrophobic material with the composition. The amount of the hydrophobic material added to the concrete composition is preferably set to 0.5 to 6% by mass of the mass of the cement added to the cement composition. A surfactant may also be added to the concrete composition.

[0030] If the above-mentioned hydrophobic coating is applied to the surface of a structure installed outdoors, water can be prevented from penetrating into the interior of the structure, effectively preventing mold from forming in the structure. In addition, if the above-mentioned hydrophobic coating is applied to the bottom of a ship, barnacles, algae, etc. can be effectively prevented from attaching to the bottom of the ship.

[0031] If the above-mentioned hydrophobic coating is applied to the surface of a metal material, the metal material can be prevented from rusting. Examples of the metal material include fences, amusement equipment, and other items that are made of metal and are prone to corrosion.

[0032] The coating is not particularly limited, and the above-mentioned hydrophobic material can be mixed into any of oily coatings and water-based coatings. The amount of the hydrophobic material mixed into the coating is preferably set to 0.5 to 6% by mass of the mass of the coating, based on the mass of the coating before the hydrophobic material is mixed. The coating is preferably a coating in which the synthetic resin component is cured by solvent volatilization. A surfactant can also be mixed into the coating.

[0033] Example

[0034] The following examples are given to explain in more detail. The following examples are merely limited examples, and the technical scope of the present invention should not be limited to the following examples.

[0035] [Example 1]

[0036] The rice ears were threshed and the dried rice grains were husked using a husking machine. 50 kg of rice husks were obtained by husking. 50 kg of rice husks were burned at 700° C. for 1 hour in a rotary kiln under oxygen supply conditions to obtain 1 kg of a black burned product.

[0037] 1 kg of the above-mentioned calcined product was mixed with 100 g of commercially available silicone oil (KF-99 manufactured by Shin-Etsu Chemical Co., Ltd.) and calcined at 700° C. for 1 hour using a rotary kiln to obtain a hydrophobic material as a white calcined product. The hydrophobic material was in the form of a powder or granular material.

[0038] The hydrophobic material of Example 1 was placed in a container in advance, and several milliliters of water was dropped thereon. As a result, the water droplets dropped on the powdered hydrophobic material formed into spheres, and it was confirmed that the hydrophobic effect was exerted.

[0039] [Example 2]

[0040] 100 g of cement, 875 g of sand and 25 g of water were mixed to obtain 1 kg of a concrete composition, and 25 g of the hydrophobic material obtained by the method of Example 1 and 6 g of a surfactant were blended and mixed into the concrete composition.

[0041] The above mixture was poured into a mold and cured for 30 days to obtain the concrete block of Example 2.

[0042] [Comparative Example 1]

[0043] A concrete block was produced in the same manner as in Example 2 except that 25 g of the commercially available silicone oil described above was blended into the concrete composition instead of the water-repellent material obtained by the method of Example 1.

[0044] [Water immersion test]

[0045] The concrete block was immersed in a sufficient amount of water and left to stand for 1 week. After 1 week, the concrete block was lifted and cut to visually check whether water had penetrated into the interior of the concrete block.

[0046] In the concrete block produced by the method of Example 2, it was confirmed that water did not penetrate into the interior of the concrete block.

[0047] In the concrete block of Comparative Example 1 prepared for comparison, water slightly penetrated into the interior of the concrete after being immersed in water for one week. It was confirmed that the longer the concrete block was immersed in water, the stronger the degree of water immersion tended to be. This confirmed that when silicone oil is added, there is a tendency that the hydrophobic performance is difficult to maintain for a long time.

[0048] [get mouldy]

[0049] The concrete block of Example 2 was placed outdoors in the shade, and the mold was visually checked. In the concrete block of Example 2, water did not penetrate the concrete block due to the strong hydrophobic effect, and mold did not occur.

[0050] In the concrete block of Comparative Example 1 prepared for comparison, water was slightly infiltrated into the concrete block, causing slight mold growth. It was confirmed that the longer the concrete block was placed outdoors, the stronger the degree of mold growth tended to be. This confirmed that when silicone oil was added, there was a tendency that the anti-mold performance was difficult to maintain for a long time.

[0051] [Example 3]

[0052] 150 g of the hydrophobic material obtained by the method of Example 1 was added to 4 liters of commercially available oily paint, and the mixture was stirred sufficiently to obtain a paint.

[0053] [Comparative Example 2]

[0054] A coating material was obtained in the same manner as in Example 3 except that 150 g of the same silicone oil as above was used instead of the hydrophobic material.

[0055] [get mouldy]

[0056] The paint of Example 3 was applied to a commercially available concrete block using a brush. The concrete block was placed outdoors in the shade and visually checked for mold. In the concrete block coated with the paint of Example 3, water did not penetrate the concrete block due to the strong hydrophobic effect, and mold did not form.

[0057] In the concrete block coated with the coating of Comparative Example 2 prepared for comparison, water was slightly infiltrated into the concrete block, causing slight mold growth. It was confirmed that the longer the concrete block was placed outdoors, the stronger the degree of mold growth tended to be. It was confirmed that when silicone oil was added, there was a tendency that the anti-mold performance was difficult to maintain for a long time.

Claims

1. A method for producing a hydrophobic material, characterized in that: have: A step of mixing the burned rice husks with silicone oil; and A step of firing a mixture of rice husks and silicone oil to obtain a hydrophobic fired product.

2. A method for producing a hydrophobic material, characterized in that: have: The process of burning rice husks; A step of mixing the burned rice husks with silicone oil; and A step of firing a mixture of rice husks and silicone oil to obtain a hydrophobic fired product.

3. The method for producing a hydrophobic material according to claim 1 or 2, wherein: The temperature when the mixture is fired is 500 to 900°C.

4. A method for producing a hydrophobic coating, characterized in that: The method comprises the step of mixing the hydrophobic material according to claim 1 or 2 with a coating material.

5. The method for producing a hydrophobic coating according to claim 4, wherein: The amount of the hydrophobic material is 0.5 to 6% by mass of the mass of the coating material, based on the mass of the coating material before the hydrophobic material is added.

6. A method for producing hydrophobic concrete, characterized in that: The method comprises the step of mixing the hydrophobic material according to claim 1 or 2 with a concrete composition.

7. The method for producing hydrophobic concrete according to claim 6, wherein: Based on the mass of cement mixed in the concrete composition, the hydrophobic material accounts for 0.5 to 6 mass % of the mass of the cement.

8. A mildew prevention method, characterized in that: The hydrophobic coating according to claim 4 is applied to a structure to prevent mold from forming in the structure.

9. A rust prevention method, characterized in that: The hydrophobic coating according to claim 4 is applied to a metal material to prevent rust.

10. A hydrophobic material, characterized in that: Contains burnt rice husk and silicone oil.