JP4808916B2 - Water and oil repellent ceramics - Google Patents

Description

  The present invention relates to a water / oil repellent ceramic in which ceramic surfaces such as tableware, tiles, sanitary ware, and insulators are made water / oil repellent.

  In the field of glass such as windshields for automobiles and flat glass for buildings, in order to maintain the water and oil repellency of the glass surface for a long period of time, metal alkoxides such as zirconium butoxide and organic metals such as ethyl silicate are used on the glass surface. After applying and baking a compound or the like to form a ceramic thin film, a contrivance has been made such as coating a water- and oil-repellent organic material (Patent Documents 1 to 3).

  In these methods, a so-called sol-gel method using an organic sol obtained using a metal alkoxide or an organometallic compound as a starting material is employed, and coating is performed by a dipping method (dip method), but the wettability to glass is low. There is a problem that film formation is difficult. For this reason, complicated process management is performed, for example, a film is formed using a special apparatus that can control the pulling speed. In addition, the method using such an organic sol can be applied to a uniform film thickness for a simple surface shape such as a plate glass or an automotive windshield, but it can be applied to tableware, tiles, and hygiene. In ceramic ceramic products having a complicated shape such as ceramics and insulators, there is a problem that a liquid puddle or the like is likely to be generated, and a part where the film thickness is too thick may be peeled off during firing. Further, there is a problem that it is difficult to apply a uniform film thickness, and it cannot be simply applied. In addition, metal alkoxides and organometallic compounds are expensive per se, and the method of obtaining a sol solution using these as starting materials is complicated and has a problem of high production cost, and the production unit price is relatively low. There is also a problem that it is not suitable for cheap ceramic products. Furthermore, metal alkoxides and organometallic compound sols are prone to hydrolysis and polycondensation reactions, and have a problem that their viscosity changes with time and are difficult to handle.

  Also, ceramics have a glaze (glassy) on the surface, but the surface is coated with a water / oil repellent such as silicon resin or fluororesin to make it water and oil repellent, making it less soiled, and washing. It has been practiced to improve the performance (Patent Document 4). Since these water and oil repellents have poor adhesion to the glaze (glassy) on the ceramic surface, the water and oil repellents will be removed when the number of uses such as washing increases, and the water and oil repellent effect will not last for a long time. There is a problem.

In recent years, products that are more friendly to people and the environment have been desired. For example, home appliances such as washing machines and automatic dishwashers that do not require detergents are provided. It is desired that the water / oil repellent film is composed only of the components contained in the water, but such a water / oil repellent film has not been put into practical use.
JP 7-315882 A Japanese Patent Laid-Open No. 6-56476 JP-A-5-170488 Japanese Patent No. 2951611

  An object of the present invention is to provide a water- and oil-repellent ceramic having an inorganic water- and oil-repellent film on the surface, which is composed of components contained in ceramics and can maintain high antifouling properties and cleanability for a long time.

  The present invention also provides water and oil repellency having a water and oil repellency film that is easily formed on the surface of glass and ceramics, is inexpensive to manufacture, and is suitable for application to a ceramic surface having a relatively complex shape. The issue is to provide ceramics.

The first water- and oil-repellent ceramic of the present invention is a mixed coating film of an aluminum hydroxide sol solution and a titanium hydroxide sol solution on the ceramic surface. After forming a coating film having a composition ratio (solid content) of 1 to 70 parts by mass, a transparent water and oil repellent film having a water repellency with a contact angle of 60 ° or more is baked at a temperature of 200 ° C. to 1400 ° C. It is characterized by being deposited.

Second repellency ceramic of the present invention, the glaze is applied to the ceramic surface, the calcined surface, a mixed coating film of the aluminum hydroxide sol solution and the hydroxide sol solution, aluminum hydroxide 100 After forming a coating film having a composition ratio (solid content) of 0.1 to 70 parts by mass of titanium hydroxide with respect to parts by mass, the film is baked at a temperature of 200 ° C. to 1400 ° C. and has a contact angle of 60 ° or more. A transparent water- and oil-repellent film having the above is formed.

The second other water- and oil-repellent ceramic of the present invention has a glaze applied to the ceramic surface , fired, further overlaid , and an aluminum hydroxide sol solution and a titanium hydroxide sol solution on the fired surface. After forming a coating film having a composition ratio (solid content) of 0.1 to 70 parts by mass of titanium hydroxide with respect to 100 parts by mass of aluminum hydroxide, the mixed coating film was formed at a temperature of 200 ° C. to 1400 ° C. A transparent water- and oil-repellent film having a water repellency with a contact angle of 60 ° or more is formed by firing.

In the first or second water- and oil-repellent ceramic, the coating film of the aluminum hydroxide sol solution and the titanium hydroxide sol solution is formed using a transfer sheet, It is obtained by applying and drying a coating solution comprising a mixture of an aluminum hydroxide sol solution and a titanium hydroxide sol solution on a transfer substrate.

  The water- and oil-repellent ceramic of the present invention has an inorganic water- and oil-repellent film made of aluminum oxide and titanium oxide on the surface of the ceramic. Also, there is an advantage that durability is maintained for a long time. In addition, a water- and oil-repellent film is formed using an aluminum hydroxide sol solution and a titanium hydroxide sol solution, and is applied to an organic sol prepared using a metal alkoxide or an organometallic compound, or to a silicon resin or a fluororesin. Compared with hydrolysis and polycondensation reactions, it is easy to handle, can form a water- and oil-repellent film at low cost, and has excellent wettability to the ceramic surface. Thus, a water- and oil-repellent film can be easily formed on the ceramic surface having a complicated shape.

  The ceramics in the first and second water- and oil-repellent ceramics of the present invention are made of glass, in particular, ceramics and glassware having relatively complicated shapes such as tableware, sanitary ware, insulators, tiles, For example, the base portion is formed using various types of porcelain, blended porcelain or the like, and then baked at 920 ° C., for example.

  The first water-repellent ceramic of the present invention will be described. The aluminum hydroxide sol solution and the titanium hydroxide sol solution are, for example, an excess amount of 3% by weight ammonia aqueous solution added to a 1% by weight aqueous solution of aluminum chloride and titanium chloride to precipitate each hydroxide, and then filtered. It is obtained by adding a 1% by mass aqueous hydrochloric acid solution to the one washed with water and adjusting the pH to 3 to 4, and an aqueous solution or an alcohol solution, each having a concentration of 0.1 to 15% by mass, preferably 1 to 5%. Mass%.

  In mixing the aluminum hydroxide sol solution and the titanium hydroxide sol solution, the composition ratio (solid content) is 0.1 to 70 parts by mass, preferably 10 to 60 parts by mass, with respect to 100 parts by mass of aluminum hydroxide. A good part. When the amount of titanium hydroxide is less than 0.1 parts by mass, the coating film becomes porous, and even when water repellency is 60 ° or less, the water and oil repellency is not sufficient, and when it is more than 70 parts by mass, The surface of the water / oil repellent film is bright and unpreferable as tableware or the like, and there is a problem that it is peeled off after precipitation or baking.

  The mixed solution may be applied to the ceramic surface by spraying, dipping, or the like, and the dry film thickness may be 0.01 μm to 100 μm, preferably 0.1 μm to 10 μm. If the film thickness is too thin, the desired effect cannot be obtained, and the desired effect can be obtained even if the film thickness is thick, but if it exceeds 100 μm, there is a problem in adhesion to the ceramic surface during firing, Moreover, since penetration etc. arise, it is not preferable.

  The aluminum hydroxide sol solution and the titanium hydroxide sol solution may be formed separately on the ceramic surface sequentially. In that case, the composition ratio in the laminated structure and the film thickness are in the above-mentioned ranges, respectively. The amount of coating should be adjusted. Since this laminated film can be integrated in the firing stage, the application order is not limited.

  In addition, in order to easily increase the film thickness of the water / oil repellent film, the coating liquid is mixed with a printing oil that can be removed by firing when firing the water / oil repellent film or a coating liquid for overcoat film formation. Alternatively, a printing oil or a coating liquid for overcoat film formation may be sprayed, for example, by spraying or the like on an aluminum hydroxide sol solution and a titanium hydroxide sol solution alone or on a mixed coating film. The mixing amount and film thickness are preferably set so as not to affect the water / oil repellent properties when a water / oil repellent film is formed by firing. Examples of the printing oil include “Printing Oil 80450” manufactured by Degussa Japan Co., Ltd., and “Degussa Film Solution No. 83454” manufactured by Degussa Japan Co., Ltd. as an overcoat film forming coating solution. Is exemplified.

  After the coating film is formed on the ceramic surface, it is baked at 200 to 1400 ° C. to form a water / oil repellent surface. The firing temperature using aluminum hydroxide and titanium hydroxide as an oxide is preferably at least 200 ° C., and the firing temperature is, for example, a glaze firing temperature or a water / oil repellent film composition within a range of 200 to 1400 ° C. It is good to adjust appropriately in relation to.

  The surface of the film thus obtained is excellent in transparency, and the composition thereof is 0.1 to 40 parts by mass, preferably 6 to 30 parts by mass of titanium oxide with respect to 100 parts by mass of aluminum oxide. Further, the water repellency (contact angle) on the surface can be 60 ° or more, and the oil repellency (contact angle) can be 50 ° or more. The contact angle is measured with a digital microscope ("VH-7000" manufactured by Keyence Corporation), and the contact angle on the surface of the obtained film is within the above-described content range of titanium oxide. Indicates the maximum value.

  Although the detailed reason why the water / oil repellent film composed of aluminum oxide and titanium oxide exhibits water / oil repellency is unknown, the present inventors have found that ultrafine irregularities are formed on the surface of the coating by firing. It has been confirmed that it is believed that it exhibits water and oil repellency.

  Since the first water / oil repellent ceramic can form a water / oil repellent film by coating, it can easily impart water / oil repellency to the surface of a ceramic or the like having a complicated shape. Such water / oil repellency and ease of production are the same as in the second water / oil repellency ceramic described later.

  Next, in the second water- and oil-repellent ceramic of the present invention, a coating film is coated on the ceramic surface on which the glaze has been applied to form a water- and oil-repellent surface in the same manner. For ceramics, the base is generally baked at 920 ° C, glazed and then baked at 1300 ° C, decorated with a painting, etc., and baked at 820 ° C. In the case of the water / oil repellent ceramic of No. 2, an aluminum hydroxide sol solution and a titanium hydroxide sol solution are used similarly to the first water / oil repellent ceramic on the surface of the ceramic coated with the glaze. A coating film is formed. At this time, examples of the glaze include wollastonite, limestone, stalagmite, zinc, and ash.

  The coating film thus formed is preferably baked at 200 to 1400 ° C., and the water repellency (contact angle) on the surface can be 60 ° or more, as with the first water / oil repellent ceramic. Also, the oil repellency (contact angle) can be 50 ° or more. In addition, in tableware made of ceramics, it is preferable that the contact angle is about 60 to 80 ° with respect to an aqueous food (for example, soy sauce), and even if the water repellency is greater than 90 °, the degree of polka dots is large, Not very good. In the second water- and oil-repellent ceramic, the obtained water- and oil-repellent film is excellent in transparency, and does not produce a luster or the like, so it does not affect the visibility of decorations such as paintings. .

  Thus, it is preferable to form the coating film after firing the glaze and fire it.

  As described above, the case where the water / oil repellent film is formed by the coating method has been described. However, it can be similarly formed by the transfer method using the transfer sheet. As the transfer sheet, an appropriate coating film made of an aluminum hydroxide sol solution and a titanium hydroxide sol solution alone or a mixture of the first and second water- and oil-repellent ceramics is applied on a transfer substrate having peelability. It was applied and dried to a thickness.

  The transfer substrate is a temporary support for transferring the water- and oil-repellent film on the substrate or on the glaze. The transfer substrate is peeled and removed at the time of transfer, for example, a durable paper having hygroscopicity, etc. A water-releasable sheet on which a water-soluble adhesive layer mainly composed of polyvinyl alcohol, dextrin and the like is thinly coated is preferably used. As a commercially available product, transfer paper “SPA 91115-11” manufactured by Marushige Kogyo Co., Ltd. Etc. are exemplified.

  From the viewpoint of handling properties as a transfer sheet, the coating liquid is mixed with the above-described printing oil or coating liquid for overcoat film formation, or an aluminum hydroxide sol solution and a titanium hydroxide sol solution alone or a mixed coating film. A printing oil or an overcoat film forming coating solution may be applied and formed in the same manner.

  The transfer sheet is placed on the substrate or glaze from the transfer substrate side, the transfer substrate is removed by dissolving the water-soluble adhesive layer in water, and the transfer layer can be transferred to the substrate or glaze In addition, by forming the water / oil repellent film by a transfer method, it is not necessary to form a coating, and the water / oil repellent film can be easily formed on site.

  Hereinafter, the present invention will be described in detail with reference to examples.

  After preparing a plate (diameter: 75 mm) -shaped body portion with a clay firing temperature of 920 ° C. using Amakusa glazed clay, after firing at 1300 ° C. using a wollastonite glazing as a glaze, a firing temperature of 800 ° C. A ceramic with glaze was prepared with the above picture.

  On the other hand, a 6.0% by mass titanium hydroxide sol aqueous solution was added to a 2.5% by mass aluminum hydroxide sol aqueous solution in an external ratio of 7% to prepare a mixed solution.

  The obtained mixed solution was coated on the ceramic having glaze prepared above by dipping method, then dried at 50 ° C. to form a coating film having a dry film thickness of 0.1 μm, and further baked at 920 ° C. A film having excellent properties was formed.

  The contact angle between the coating surface and water was measured and found to be 78 °. In addition, when the contact angle with the coating surface was measured in the same manner using Lulla oil, it was 73 °.

  The resulting surface does not exhibit water and oil repellency due to the influence of the rinsing agent in the rinsing (hydrophilic) treatment process in an automatic dishwasher, resulting in a phenomenon in which moisture is dried unevenly during the drying process. It was not. Further, after 100 washing tests were performed using only water without detergent thereafter, the contact angle between the surface and water was measured to be 70 °, and the water repellency showed high durability.

  In the mixed solution in Example 1, 6.0% by mass of a titanium hydroxide sol aqueous solution was added in an external ratio of 0.1% by mass to prepare a mixed solution.

  The obtained mixed solution was coated on the ceramic having glaze prepared above by dipping method, then dried at 50 ° C. to form a coating film having a dry film thickness of 0.1 μm, and further baked at 920 ° C. A film having excellent properties was formed. The contact angle between the coating surface and water was measured and found to be 71 °. Moreover, the obtained surface showed the same performance as Example 1.

  In the mixed solution in Example 1, 6.0% by mass of a titanium hydroxide sol aqueous solution was added in an external ratio of 30% by mass to prepare a mixed solution.

  The obtained mixed solution was coated on the ceramic having glaze prepared above by dipping method, then dried at 50 ° C. to form a coating film having a dry film thickness of 0.1 μm, and further baked at 920 ° C. A film having excellent properties was formed. The contact angle between the coating surface and water was measured and found to be 70 °. Moreover, the obtained surface showed the same performance as Example 1.

  An overcoat film-forming coating solution {Degussa Japan Co., Ltd. is added to a mixed solution obtained by adding 6.0% by mass of titanium hydroxide solethyl alcohol solution to 2.5% by mass aluminum hydroxide solethyl alcohol solution. “Degussa Film Solution No. 83454”} manufactured by Co., Ltd. was mixed in an amount of 9 times to prepare a coating solution. This coating solution was applied to one side of a transfer paper “SPA 91115-11 manufactured by Maruhan Paper Industries Co., Ltd.” by a spray method and dried at 50 ° C. to form a coating film having a dry film thickness of 50 μm.

The transfer sheet was laminated from the base paper side onto the ceramic surface having the glaze obtained in Example 1 in water, the base paper was peeled off, and the coating film on the transfer sheet was transferred to the glaze side surface of the ceramic having the glaze. . After the transfer, the film was baked at 920 ° C. to form a film having excellent transparency. The contact angle between the coating surface and water was measured and found to be 75 °. Moreover, the obtained surface showed the same performance as Example 1.
(Comparative Example 1)

In the ceramics having glaze prepared in Example 1, the contact angle between the surface and water in a state where water / oil repellent treatment was not performed was 10 ° or less.
(Comparative Example 2)

The ceramic surface having the glaze produced in Example 1 was coated with a 2.5 mass% aluminum hydroxide sol solution by dipping, and then dried at 50 ° C. to form a coating film having a dry film thickness of 0.1 μm. Furthermore, it baked at 920 degreeC. The contact angle between the coating surface and water was measured and found to be 60 ° or less.
(Comparative Example 3)

  After coating 6.0 mass% titanium hydroxide sol solution on the surface of the ceramic having glaze prepared in Example 1 by dipping, it was dried at 50 ° C. to form a coating film having a dry film thickness of 0.2 μm. And baked at 920 ° C. The contact angle between the coating surface and water was measured and found to be 10 °, and the surface had a rainbow-like luster, which was not suitable for tableware ceramics.

  From Examples 1 to 3 and Comparative Examples 2 and 3, by controlling the amount of titanium hydroxide sol added to the aluminum hydroxide sol, the contact angle is one of the indexes that can easily remove dirt due to water and oil repellency. It can be seen that can be controlled.

  In addition, after applying the same amount of water-based dye-based ink as pseudo-stains to each of the dishes prepared in Example 1 and Comparative Example 1, a washing test using a water-only shower was performed without adding a detergent. The results are shown in FIGS. The left side of FIG. 1 is the dish of Example 1, and the right side is the dish of Comparative Example 1, showing a state where the same amount of water-based dye-based ink is applied. In Example 1, it can be appropriately formed into a ball shape to make it water repellent, whereas in Comparative Example 1, it does not show water repellency. And FIG. 2 shows the state after the washing test by the shower only of water without adding detergent, and right and left are the same as FIG. As can be seen from FIG. 2, it can be seen that the cleaning performance in Example 1 is clearly improved as compared with Comparative Example 1.

FIG. 1 is a view showing a state in which the same amount of water-based dye-based ink is applied to the plate (left side) obtained in Example 1 and the plate (right side) obtained in Comparative Example 1. FIG. 2 is a diagram illustrating a state after the cleaning test using the water-only shower is performed on each dish illustrated in FIG. 1.

Claims (4)

It is a mixed coating film of an aluminum hydroxide sol solution and a titanium hydroxide sol solution on the ceramic surface, and has a composition ratio (solid content) of 0.1 to 70 parts by mass of titanium hydroxide with respect to 100 parts by mass of aluminum hydroxide. After forming the coating film, firing is performed at a temperature of 200 ° C. to 1400 ° C., and a transparent water and oil repellent film having a water repellency with a contact angle of 60 ° or more is formed. Water / oil repellent ceramics. A glaze is applied to the surface of the ceramic, and a fired surface is a mixed coating film of an aluminum hydroxide sol solution and a titanium hydroxide sol solution, and 0.1 to 70 titanium hydroxide with respect to 100 parts by mass of aluminum hydroxide. After forming a coating film having a composition ratio (solid content) of parts by mass, baking is performed at a temperature of 200 ° C. to 1400 ° C. to form a transparent water / oil repellent film having water repellency with a contact angle of 60 ° or more. Water- and oil-repellent ceramics characterized by A glaze is applied to the surface of the ceramic , fired, further overlaid, and on the fired surface, a mixed coating film of an aluminum hydroxide sol solution and a titanium hydroxide sol solution, and 100 parts by weight of aluminum hydroxide On the other hand, after forming a coating film having a composition ratio (solid content) of 0.1 to 70 parts by mass of titanium hydroxide, it is baked at a temperature of 200 ° C. to 1400 ° C. and has a water repellency with a contact angle of 60 ° or more. A water- and oil-repellent ceramic characterized in that a water- and oil-repellent film is formed. The coating film of the aluminum hydroxide sol solution and the titanium hydroxide sol solution is formed using a transfer sheet, and the transfer sheet is formed on the transfer substrate with an aluminum hydroxide sol solution and a titanium hydroxide sol solution . The water- and oil-repellent ceramic according to any one of claims 1 to 3, wherein the water- and oil-repellent ceramic is obtained by coating and drying a coating solution comprising a mixture .

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