JP4976810B2 - Coating member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coating member having high water repellency and high sliding property and a method for producing the same.

  Organic base materials or inorganic base materials made of plastic, rubber, metal, ceramics or the like are used for building materials. By applying a coating member to the surface of the base material to impart water repellency and wear resistance, the product made of the base material can be made highly durable and have a long service life. High added value can be achieved. Therefore, research and development of various coating members have been conventionally performed, but it has been difficult to impart both high water repellency and high sliding properties to the substrate surface. The sliding property refers to a property that combines the specific wear amount and the friction coefficient. When the specific wear amount is small and the friction coefficient is low, the sliding property is high. Abrasion resistance refers to the degree of resistance to wear.

  Among such coating members, a PTFE (fluororesin) coating member is currently frequently used as a water-repellent coating member. However, since the PTFE coating member is manufactured by baking, for example, it is difficult to coat the surface of a base material having no heat resistance, and the wear resistance is not necessarily sufficient, and the practical use is limited. ing.

  In addition, various methods for coating silicate and silica have been reported in the past. For example, inorganic coating members that provide stable coatings that do not easily crack, methods for producing water-resistant glassy coating members, and coating on metal substrates Techniques relating to compositions for doing so have been proposed. As in Patent Documents 1 and 2, it is a known technique to use silicate or silica as a stability or water-resistant coating material.

Japanese Patent Laid-Open No. 7-2511 Japanese Patent Laid-Open No. 11-181352

  However, by coating the surface of the substrate with silicate and silica coating material, or adding and mixing a filler such as carbon fiber to the silicate and silica coating material, the substrate has high water repellency. It has not been realized that high mobility is imparted together.

  Then, the objective of this invention is providing the coating member which solves the said subject, and has high water repellency and high sliding property, and its manufacturing method.

In order to achieve the above object, the coating member of the present invention is coated with a coating material containing 67 to 82 parts by weight of silica and / or silicone resin and 18 to 33 parts by weight of a modified fluororesin on the surface of the substrate. It is what.

  The base material may be a single layer made of plastic, rubber, metal, ceramics, wood, or organic fiber, or a laminate made of two or more of them.

Moreover, the manufacturing method of the coating member of this invention coats the coating material which contains 67-82 weight part of silica and / or silicone resin, and 18-33 weight part of modified fluororesins on the surface of a base material. .

  A silicate solution may be applied to the surface of the substrate, and after the silicate solution is dried, a coating solution containing silica and / or silicone resin and modified fluorine resin may be applied to the dried surface.

  The modified fluororesin is preferably obtained by modifying the fluororesin by irradiating with ionizing radiation under the condition of the melting point of the fluororesin or higher and the oxygen concentration of 1.3 kPa or lower.

  The present invention exhibits the following excellent effects.

  (1) Both high water repellency and high sliding property can be imparted to the substrate.

  Hereinafter, an embodiment of the present invention will be described in detail.

  As a result of intensive research aimed at developing a coating material capable of imparting both water repellency and abrasion resistance to a substrate, the present inventors have made a study on silica and / or silicone on the surface of the substrate. It has been found that a coating member having excellent water repellency and sliding property can be obtained by coating a coating material containing a resin and a modified fluororesin, and the present invention has been completed through further research. In other words, the wear resistance of silica and silicone resin is not so bad, but by adding and mixing the modified fluororesin, the wear resistance and low friction properties are remarkably exhibited and the sliding performance is greatly improved. It is done. Also, good results can be obtained by mixing (mixing) silica, silicone resin, and modified fluororesin.

  Here, the silica used in the present invention will be described. Silica includes silicate, silica sol, organosilicon compound and the like. Examples of the organosilicon compound include methyl silicate, ethyl silicate, propyl silicate, butyl silicate, alkoxysilane, or a mixture thereof. Among these, methyl silicate and ethyl silicate are most preferable from the viewpoint of cost and availability. Examples of the silica sol include those obtained by neutralizing or hydrolyzing an organic silicon compound or silicate with an acid or alkali, and those obtained by dispersing silica fine particles.

  Next, the silicone resin used in the present invention will be described. The silicone resin has a structure in which a polyfunctional siloxane component is copolymerized, and examples thereof include a methyl silicone resin, a phenyl methyl silicone resin, and a modified silicone resin.

  The coating member according to the present invention is obtained by coating the surface of a base material by, for example, applying a coating material containing silica and / or silicone resin and modified fluororesin. Thereby, high water repellency and high sliding property can be imparted to the base material, and water resistance, flame resistance, antifouling property and high strength can be imparted together.

  Further, by coating the surface of a combustible organic base material such as plastics with the coating material of the present invention, the organic base material can be made flame resistant and the strength can be remarkably improved.

  The base material is preferably a single layer made of plastic, rubber, metal, ceramics, wood or organic fiber or a laminate made of two or more of them. Of course, the present invention is not limited to these examples. Similarly, if the substrate is equivalent to or similar to these, similarly, silica and / or silicone resin and modified fluorine resin are applied to the surface of the substrate. The coating material may be coated to form the coating member of the present invention. An organic fiber refers to an aramid fiber, a polyparaphenyline benzoxazole fiber, or the like.

  Thereby, high water repellency and high sliding property can be provided to the base material which consists of plastics, rubber | gum, a metal, ceramics, and these laminated bodies. Moreover, high water repellency and high slidability can be imparted to an organic base material having no heat resistance and made of a low-strength organic material, such as a base material made of paper, wood, bamboo, organic fiber, or the like.

  Furthermore, it is expected that the coating member of the present invention can create new technologies and new industries in the fields of OA, automobiles, and industrial machinery. Products such as OA parts (rollers, separation claws) having high water repellency / sliding property and pistons for automobiles, which include the coating member of the present invention as constituent elements, are expected. In addition, examples of products to which the present invention is applied include plastics products, rubber products, metal products, ceramic products, and products obtained by combining them.

  Next, the effect of using silica will be described.

  When an organosilicon compound or silicate is used as silica, a solution neutralized or hydrolyzed with an acid or alkali is used as a raw material for the coating solution. When these solution components are applied to the substrate surface, the organosilicon compound reacts with moisture in the air to form a film to form a silica coating film. In the present invention, the modified fluororesin powder is dispersed in the silica coating film.

  Further, when a coating liquid containing a silica sol-containing solution in which silica fine particles are dispersed is applied to the substrate surface as silica, a film is formed by drying to form a silica coating film.

  These silica coating films are crystallized and dense and impermeable to water. In the present invention, since the modified fluororesin is mixed in this film, the film has excellent water repellency and sliding properties.

  In addition, by applying a silicate solution to the surface of the base material and drying the silicate solution, by applying a coating liquid containing silica and / or silicone resin and a modified fluororesin on the dry surface, A first silica coating film that does not contain the modified fluororesin and a second silica coating film in which the modified fluororesin is mixed may be sequentially laminated on the substrate.

  In addition, after apply | coating a silicate solution, you may make it contact with an acid or a carbon dioxide gas.

  By comprising in this way, the 1st silica coating film can fulfill | perform the function of the contact bonding layer of a base material and a 2nd silica coating film, and can make a coating film strong.

  As described above, the present invention not only gives the base material both high water repellency and high sliding property, but also improves the strength of the organic base material made of an organic material, and makes the product using the base material highly durable. Enables longer life and longer life. Such products have the advantage that they can be easily wiped off or washed away because of their high water repellency.

  In the present invention, it is possible to use a photocatalyst to improve the antifouling property. That is, the photocatalyst generates active oxygen by the light energy, and the dirt is decomposed by the active oxygen. Examples of the photocatalyst include metal oxides such as titanium oxide, zinc oxide, lead oxide, tin oxide and iron oxide, metal sulfides such as cadmium sulfide and molybdenum sulfide, ceramics such as perovskite compounds, metal complexes such as ruthenium complexes, Organic semiconductors such as polyphthalocyanine and polyaniline. Preferable examples include titanium oxides such as anatase and brookite, those doped with nitrogen and sulfur, and photocatalysts that are responsive to visible light by creating oxygen defects.

  The photocatalyst may be made from a photocatalyst precursor. Examples of the photocatalyst precursor include organic titanium such as titanium alkoxide, peroxides (peroxotitanic acid), titanium metal complexes, and the like, which are not photocatalysts as they are, but can become photocatalysts by heating or drying. . In particular, organic titanium compounds such as titanium alkoxide and acetylacetonate and titanic acid peroxide are preferable.

  A silica coating film containing a photocatalyst can be obtained by adding a photocatalyst to a solution containing the aforementioned organosilicon compound or silica sol. Moreover, when adding a photocatalyst precursor instead of a photocatalyst, the silica coating film containing a photocatalyst is obtained by heating or drying after coating a base material. As a result, a coating member having further excellent antifouling property can be obtained by photocatalytic action.

  Examples of the method for applying the solution to an organic substrate include brush coating, spray coating, dip coating, roll coating, and printing.

  The drying may be room temperature drying or heat drying, and heat drying can be faster, and in that case, infrared heating, ultraviolet heating, a dryer, or the like can also be used.

Next, although an example of the present invention is described concretely, the present invention is not limited at all by this example. In the examples, an aluminum plate was used as a base material, and a coating material was applied to the surface of the aluminum plate to produce a coating member.
(1) Manufacture of a coating member After spraying 0.003 weight% sodium silicate aqueous solution on the surface of a 2 mm-thick aluminum base material, it was dried with an infrared lamp. Thereafter, the solution shown in Table 1 was uniformly applied by spraying, and the applied solution was dried to produce a coating member having a coating film having a thickness of 30 μm. As shown in Table 1, five types of Examples 1 to 5 were used as examples, and two types of solutions of Comparative Examples 1 and 2 were used as comparative examples.

Silica A is a 50 wt% isopropyl alcohol solution of silica sol prepared by hydrolyzing methyl silicate with acetic acid.
Silica B is a 50 wt% ethyl alcohol solution of silica gel prepared by hydrolyzing ethyl silicate with hydrochloric acid.

  The silicone resin is trade name SR2405 manufactured by Toray Dow Corning.

As PTFE, trade name P-192 manufactured by Asahi Glass Co., Ltd. was used. This PTFE was modified by irradiation with 100 kGy of an electron beam (acceleration voltage 2 MeV) at an oxygen concentration of 0.13 kPa and a nitrogen atmosphere at a temperature of 340 ° C. This modified PTFE was finely pulverized to a mean particle size of 20 μm by a jet mill, and mixed with a solution of silica A or silica B or a silicone resin at a composition ratio shown in Table 1. Note that the oxygen concentration is displayed in pressure because the absolute amount of oxygen is important.
If the oxygen concentration exceeds 1.3 kPa, the degree of modification (crosslinking) of the modified fluororesin is remarkably reduced and improvement in wear characteristics cannot be expected. Therefore, the oxygen concentration is preferably 1.3 kPa or less.
(2) Test method and results The coating member thus obtained was evaluated for water repellency and sliding properties. About water repellency, Kyowa Interface Science Co., Ltd. contact angle meter CA-D type was used, it adjusted to droplet diameter 1.9mm, the contact angle of water was measured, and water repellency was evaluated by the contact angle.

  The sliding characteristics were measured by the following method. For the test, a ring-on-desk wear test device was used, and a cylindrical ring made of SUS304 (outer diameter 25.6 mm, inner diameter 20.6 mm, average roughness 0.6 μm) and coating member were slid according to JIS K7218. . The pressure was 0.1 MPa, the speed was 50 m / min, the atmosphere was air, the temperature was 20 ° C., and the specific wear amount and the friction coefficient after 20 minutes were measured.

The weight loss after 20 minutes was measured, and the specific wear amount V _SA was obtained from the following equation.

V _SA = V / (P · L)
V: wear amount, P: test load, L: average slip distance Examples 1 to 5 have a high contact angle, excellent water repellency, good wear resistance, a low friction coefficient, and low friction. It has excellent characteristics.

  On the other hand, Comparative Example 1 in which the modified fluororesin was not mixed has a low contact angle and poor water repellency and low wear resistance. In Comparative Example 2 using an unmodified fluororesin, the fluororesin aggregates and does not disperse uniformly. Like Comparative Example 1, the contact angle is low, the water repellency is poor, and the wear resistance is low. .

  From the above test results, it was proved that the coating member according to the present invention imparts both high water repellency and high sliding properties to the substrate.

Claims (5)

A coating member, wherein a coating material containing 67 to 82 parts by weight of silica and / or silicone resin and 18 to 33 parts by weight of a modified fluororesin is coated on the surface of a substrate.   2. The coating according to claim 1, wherein the base material is a single layer made of plastic, rubber, metal, ceramics, wood, or organic fiber, or a laminate made of two or more of them. Element. A method for producing a coating member, comprising coating a surface of a substrate with a coating material containing 67 to 82 parts by weight of silica and / or silicone resin and 18 to 33 parts by weight of a modified fluororesin.   A silicate solution is applied to the surface of a substrate, and after the silicate solution is dried, a coating liquid containing silica and / or silicone resin and modified fluorine resin is applied to the dry surface. The manufacturing method of the coating member of Claim 3.   5. The modified fluororesin is obtained by modifying a fluororesin by irradiating with ionizing radiation under a condition of a melting point of the fluororesin or higher and an oxygen concentration of 1.3 kPa or lower. The manufacturing method of a coating member.