WO2001036190A1 - Structure and film having surface exhibiting high hardness and providing high slippage of water, and method for preparation thereof - Google Patents

Abstract

A structure and a film having a surface which exhibits high hardness and provides excellent slippage of water, characterized in that at least a part of the surface of a base structure having a first roughness further has a second roughness which is smaller than the first roughness. The structure or film has a surface which is markedly slippery for water drops and at the same time exhibits high hardness.

Description

 Itoda »

 High hardness and high water-sliding surface structure, membrane and method for producing the same

 Technical field

 TECHNICAL FIELD The present invention relates to a surface structure, a film, a method for producing the same, and a coating agent used for the same, which are easy to control the structure and have both excellent lubricity and hardness.

 Background technology

 On a water-repellent fixed surface, the wettability of a solid smooth surface to a liquid is generally described by Young's equation as follows.

γ _sv = γ y cos Θ

Ί y _{γ ΐν} is the surface (interface) free energy between solid-gas, solid-liquid, and liquid-gas, and 0 is the contact angle. In general, many water-slidable surfaces are obtained by treating the surface with silicon fluoride. A water-slidable surface obtained from a smooth surface by such a conventional technique has a contact angle with water of about 100 to 110 °, and the falling angle of a droplet is 50 to 200 mg. ~ 60 °. And this treatment has already been put to practical use for clothing, car glass, painted surfaces, etc. On the other hand, it is known that by providing a low energy surface with an appropriate structure, a surface having a very high water repellency (super water repellency) having a contact angle of 150 ° or more can be obtained. The contribution of the surface energy of the solid increases when wetting on the roughness-imparted surface; hydrophilic ones become more hydrophilic and water-repellent ones become more water-repellent. Wenzel [RN Wenzel, J. Phys. Colloid Chem., 53, 1466 (1949)] presented the following equation and described the wetting on a water-repellent solid surface with roughness.

cos Θ = r (γ 3i— γ ι _ν ) / y τ

 Θ and 6 'are the contact angles of the smooth and rough surfaces, respectively, and r is the roughness factor, which is the actual surface area increased by the surface roughness divided by the apparent surface area. Cassie [ABD Cassie, Discuss. Farady Soc., 3, 11 (1948)] assumes that the interface with a liquid is a composite phase of solid and gas, and the contribution from each phase depends on the area fraction. In consideration of the fact that the contact angle between gas and water can be approximated to 180 °, the water repellency due to air entering the solid-liquid interface was described by the following equation.

cos Θ '= f 1 cos Θ (1-f ι) cosl80 ⁰ = f icos Θ i + fi -1 fi and Θi are the solid area fraction at the interface with the liquid and the contact angle on the smooth solid surface, respectively. Johnson Jr. and Dettre [RE Johnson Jr, and RH Dettre. Adv. Chem. Ser., 43, 112 (1963)] assumed a model sinusoidal curve and modeled single-mode roughness. The water repellency (contact angle) was calculated theoretically. When the surface roughness is added to the smooth water repellent surface, the water repellency first increases in the Wenzel mode, and when the roughness exceeds a certain level, the air enters the solid-liquid interface and the Cassie module starts to operate. This was demonstrated by experiments on a water-repellent coating material mixed with wax.

 It has become known that the emphasis on water repellency due to such roughness can provide an extremely high water repellent (super water repellent) surface with a contact angle of 150 ° or more. Since 1990, various studies have been conducted.

 The super-water-repellent surface can significantly reduce the contact area between the surface and water, thus suppressing the progress of chemical reactions, formation of local batteries, short-circuits of electric circuits, or the formation of hydrogen bonds through water. be able to. For this reason, it prevents snow and raindrops, prevents water, and has electrical insulation. For various purposes such as reducing the resistance to water, compared to a water-repellent surface with a contact angle of about 100 to 110 ° obtained from a conventional smooth surface, Higher effects can be expected. The applicable range is the exterior of vehicles such as automobiles and Shinkansen, bottom paint, exterior lights, kitchen and kitchen utensils, bathrooms and washrooms and their supplies, fishing nets, buoys, dental supplies, electrical equipment, and residential floors. And exteriors, entrance doors and knobs, roofs, pools and poolsides, piers, gates, bosses, benches, steel towers, antennas, wires, garages, tents, umbrellas, raincoats, sporting goods and sports clothing, helmets Leather products such as shoes, shoes, etc., outdoor loudspeakers and audio equipment such as cameras, video, paper, speakers, etc., lubricating nozzles such as power terminals, carpets, gasoline stands, oil refineries, etc. It covers a wide range, such as chemical plants, metal tools, nails, screws, and buckets.

Conventionally, such super water-repellent films have been realized by a single mode of roughness or a fractal surface structure. However, in order for this super-water-repellent surface to exhibit high water-repellency (to reduce the resistance between the surface and water to such an extent that the water drops fall with only a few degrees of inclination), the surface is super-water-repellent. It is not enough to provide the surface of the super-water-repellent film with a fine uneven structure. It becomes necessary (Japanese Patent Application No. 1 1 — 2964 636, Langmuir, v-16, 13, 5754 (2000)). In this case, there was a disadvantage that the surface structure was fine and the hardness was low. Super-water-repellent materials that combine super-water-repellency, high water-sliding properties, and hardness have traditionally been extremely difficult to design, and have not been manufactured so far. For this reason, the practical use of super water-repellent materials has been delayed, despite the fact that many applications are expected.

 Disclosure of the invention

 An object of the present invention is to provide a super-water-repellent surface structure and a film that are easy to control the structure and have both excellent hardness and water-slidability, a method for producing the same, and a coating agent used in the production method. It is in.

 In the present invention, the following high hardness and high water sliding surface structure is provided.

 A high-hardness and high-sliding surface structure in which at least a part of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness. In the production of such a structure, a roughness smaller than that of the basic structure is introduced into the basic structure such as a porous, needle-like, column-like, or groove-like shape by coating, cutting, grinding, etching, or the like. Even on a smooth surface that does not have a basic structure in advance, grooves or columns may be formed by cutting or the like, and at the same time, appropriate roughness may be introduced to the cut side surface.

 Further, in the present invention, in order to further improve the super water repellency, the surface of the base material is formed by a first uneven surface formed with a first surface roughness and a first unevenness formed by the first surface roughness. The underlayer is formed on a surface having a double surface roughness with at least a part of the second uneven surface formed on the first uneven surface with a small second surface roughness. It is characterized in that a high hardness and high water-sliding film is produced by performing a water-repellent treatment on at least a part of the film.

As a method for producing a high hardness and high water-sliding film satisfying such a requirement, for example, a metal alkoxide and / or a sol having a primary particle diameter of 100 nm or less are separated from these in a solvent, A substance or a substance that has the property of decomposing, burning, and sublimating at temperatures from room temperature to 700 ° C is prepared as a solution or emulsion added to a solvent and used at room temperature (room temperature). After forming the film, a method of keeping the temperature from room temperature to 700 ° C. for a certain period of time to remove the above substances can be mentioned. Further, it is possible to satisfy the above-mentioned requirements by mixing particles having different sizes (particle diameters) or controlling the aggregation diameter of the particles. For the water-repellent treatment, it is possible to use a fluorine-silicon based water-repellent or a combination thereof as appropriate. In addition, in order to impart self-cleaning properties to the high hardness and high water-sliding surface structure and the film according to the present invention, a photocatalyst can be contained in the porous underlayer.

 More specifically, the present invention provides the following.

 (1) A high-hardness and high-slidability film having both practical hardness and high-slidability.

 (2) High hardness and high water-sliding membrane with the following characteristics.

 The contact angle is 140 ° or more, the falling angle of a 7 mg droplet is 30 ° or less, and the hardness is H or more in pencil hardness. The falling angle is preferably 20 ° or less, and more preferably 15 ° or less. In terms of hardness, the pencil hardness is preferably 2 H or more, more preferably 3 H or more. It is to be noted that both of the falling angle and the hardness can be achieved by applying the present invention.

 (3) At least a portion of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness. High hardness and high water-sliding surface structure.

 (4) A second surface roughness smaller than the first surface roughness is provided to at least a part of the surface of the basic structure having the first surface roughness, and at least, A high hardness and high water-slidable surface structure, wherein a water-repellent layer is formed on at least a part of the surface of the structure.

 (5) To form a structure in which at least a part of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness. A method for producing a high-hardness and high-sliding surface structure, wherein a groove is formed in at least a part of the surface of the basic structure by cutting.

 (6) To form a structure in which at least a part of the surface of the basic structure having the first surface roughness has a second surface roughness smaller than the first surface roughness. A method for producing a high hardness and high water-sliding surface structure, characterized in that at least a part of the surface of the basic structure is provided with roughness by grinding, etching or coating.

(7) The first uneven surface formed with the first surface roughness and the first surface roughness The second surface roughness is smaller than that of the second uneven surface formed on at least part of the first uneven surface on the first uneven surface. Characterized by high hardness and high water-sliding membrane.

 (8) The high hardness and high water-sliding membrane according to (7), wherein the first surface roughness force is in the range of Si0Onm to 2 / im and the second surface roughness is less than 1 OOnm. Although the lower limit of the second surface roughness is not particularly limited, the surface is further improved by superposing the water repellency by interposing air in the concave portion due to the surface roughness, and the second phase is formed by utilizing the phase separation and the inclusion of fine particles. From the viewpoint of practically forming the surface roughness of No. 2, the lower limit of the second surface roughness is about 1 nm, and more preferably about 3 nm.

 (9) The first uneven surface is formed by using phase separation, and the second uneven surface is formed by using phase separation or contained particles. The high-hardness / high-sliding water film described in the above.

 (10) The first uneven surface is formed using particles having a larger particle diameter or agglomerated particles, and the second uneven surface is formed using particles having a smaller particle diameter or primary particles. (7) or (8), wherein the high hardness and high water-sliding film is formed.

(11) The high hardness and high water sliding film according to any one of (7) to (10), which is a transparent film.

 (12) The high hardness and high water-sliding film according to any one of (7) to (11), wherein a water-repellent layer is formed on at least a part of the surface.

 (13) The high hardness and high water-sliding film according to any one of (1), (2), and (7) to (12), wherein the photocatalyst is dispersed.

 By dispersing the photocatalyst (typically, titanium oxide) in this way, the self-cleaning property of the high hardness and high water-sliding film of the present invention can be obtained (Japanese Patent Application No. Hei 11-112946). Can be given.

 (14) The high hardness and high water-sliding film according to any one of (7) to (12), wherein the photocatalyst is dispersed in a valley portion of the surface roughness.

 (15) The high hardness and high water-sliding surface structure according to (3) or (4), wherein the photocatalyst is dispersed.

(16) The photocatalyst is characterized in that it is dispersed in the valleys of the surface roughness. (3) Or (4) a high-hardness, high-sliding surface structure.

 By disposing the photocatalyst at such a position, the direct decomposition of the water-repellent film due to the generated radicals is reduced, and the self-cleaning effect due to the addition of the photocatalyst can be more effectively emphasized.

 (17) A phase separation is formed between the raw material liquid of the membrane base material, a predetermined solvent, a substance to be removed after the raw material liquid of the membrane base material is solidified, and a sol having a primary particle diameter of 100 nm or less. An undiluted solution of a coating agent for forming a high hardness and high water-sliding film comprising:

 Here, the “raw material liquid for the membrane base material” is capable of forming a phase separation with other components, and is also required to give practical hardness to the finally obtained water-slidable film. Any material can be used as long as it is possible. An example is a metal alkoxide which is a raw material for the sol-gel method. In addition, the “substance that is removed after the raw material liquid of the membrane base material is solidified” includes a substance having a property of being removed at a temperature from room temperature to 700 ° C. (particularly, from room temperature to 70 ° C.). A substance having the property of decomposing, burning, and sublimating at a temperature of up to 100 ° C).

 (18) a metal alkoxide, a sol having a primary particle diameter of 100 nm or less, and a substance which has a property of being phase-separated from these in a predetermined solvent and being removed at a temperature from room temperature to 700 ° C. A coating agent for forming a high-hardness and high-slippery film, comprising a solution in which a solvent is added to a solvent or an emulsion.

 “The property removed at room temperature to 700 ° C.” means, for example, the property that decomposes, burns, and sublimes at such a temperature, and a group of substances having such properties ( For example, a substance that can form a phase separation with other components is appropriately selected from among a group of thermosublimable substances). These include, for example, organic polymers (which generally decompose and burn when heated), are insoluble in metal alkoxides, and are soluble in certain solvents such as ethanol and ethyl acetate. Things can be mentioned.

 (19) The coating agent according to (18), wherein the sol comprises a colloidal silica sol.

(20) a metal alkoxide, having a property of phase separation with a predetermined solvent and having a property of being removed at a temperature from room temperature to 700 ° C., and a dispersion diameter in a phase separation state of 100 nm that's all A coating material for forming a high-hardness and highly water-slidable film, comprising a solution or an emulsion obtained by adding a substance having a particle diameter of less than 100 nm to a solvent.

 (21) After applying the coating agent according to any one of (18) to (20) to the substrate, heat treatment is performed at a temperature ranging from room temperature to 700 ° C to obtain a microporous material. Forming a high hardness and high water-sliding film on the substrate by forming a water repellent on at least a part of the underlayer.

 Furthermore, in the present invention, it is also possible to apply a coating agent containing particles of different sizes as follows and a method of forming a high hardness and high water-sliding film using the coating agent. .

 (22) A coating agent for forming a high hardness and high water-sliding film, comprising particles or aggregated particles having a particle diameter of 100 nm or more and particles or primary particles having a particle diameter of less than 100 nm.

 (23) The coating agent according to (22) above is applied to a substrate, and the first surface roughness is formed by particles having a particle diameter of 100 nm or more or aggregated particles. A first uneven surface formed and a second surface roughness smaller than the first surface roughness formed by particles or primary particles having a particle diameter of less than 100 nm. An underlayer having a surface having a double surface roughness with the second uneven surface formed on the uneven surface is formed, and a water repellent is applied to at least a part of the underlayer. A method of forming a high hardness and high water-sliding film on a material.

 Further, in the present invention, the following method can be adopted.

 (24) A first uneven surface having a first surface roughness, and at least a portion formed on the first uneven surface with a second surface roughness smaller than the first surface roughness. A method of producing a high hardness and high water-sliding film by subjecting at least a part of a substrate surface having a double surface roughness to the second uneven surface to a water-repellent treatment.

 (25) The first uneven surface has a surface roughness of 100 η ΐΏ to 2 μπι, and the second uneven surface has a surface roughness of less than 100 nm. Method.

 (26) The method according to any one of (21) to (25), wherein a fluorine-based water repellent is applied.

(27) By using the coating agent according to any one of (18) to (20), the final state is obtained by adjusting the state of the phase separation and adjusting the heat treatment step. Water slide The method for adjusting the slipperiness strength and / or the hardness of the water-soluble membrane.

 Brief explanation of drawings

 FIG. 1 is a diagram showing a phase diagram of a three-component system including three components of a solvent, a metal alkoxide, and a polymer according to Example 1.

 FIG. 2 is a diagram showing a scheme for forming a phase separation according to Example 1.

 FIG. 3 is a diagram illustrating an assumed phase separation state according to the first embodiment.

 FIG. 4 is a diagram showing an SEM photograph of the surface of the microporous material obtained in Example 1.

 Fig. 5 is an assumed view of the cross section of the micropore shown in Fig. 4.

 FIG. 6 is a schematic cross-sectional view schematically showing a substrate having only the first uneven surface. FIG. 7 is a schematic cross-sectional view schematically showing a substrate in which a second uneven surface is formed on a first uneven surface.

 FIG. 8 is a diagram showing a SEM photograph of the film surface obtained in Example 2. FIG. 9 is a diagram showing the relationship between the surface roughness and the contact angle in the third embodiment. FIG. 10 is a diagram showing the contact angles of water droplets on the surface obtained according to Example 4.

 Best form to carry out the invention

 Hereinafter, embodiments will be described specifically and in detail to facilitate understanding of the present invention.

In order to obtain good slipperiness, the difference between the advancing contact angle (contact angle on the advancing side of the droplet) and the receding contact angle (contact angle on the retreating side of the droplet) when the droplet falls on the inclined surface In order to achieve this, it is effective to impart a certain degree of roughness to the film and make the surface water-repellent to increase the contribution of air penetration (Johnson Jr.). , RE & Dettre, RH Contact Angle Hysteresis, I. Study of an Ideal Rough Surface, Adv. Chem. Ser., 43, 112-135, (1963)). Specifically, it is most desirable to make the surface structure acicular in order to obtain good lubricity. For this reason, much research on the development of super water-repellent films has been conducted toward the needle-like structure to date. However, the overall strength is governed by the strength of individual needles in a needle-like structure, and a super-water-repellent film with fine irregularities can maintain the surface hardness in such a structure. Can not. In view of such circumstances, the present inventors have intensively studied the structure of the film surface in order to maintain the slipperiness and water repellency and to give the film a practical hardness. As a result, at least a part of the basic structure having a certain surface roughness is given a roughness smaller than the surface roughness of the grave structure, and at least a part of the entire structure surface is provided. It was discovered that a high water repellency can be obtained by forming a water repellent layer on the substrate. That is, the high hardness and high water sliding surface structure according to the present invention includes at least a part of the surface of the basic structure having the first surface roughness, and the first surface of the surface of the basic structure. By giving the second surface roughness smaller than the roughness, a surface morphology combining two or more roughnesses having different sizes is formed, and at least the surface of the basic structural body is formed. At least a part thereof is formed with a water-repellent layer. However, when the material itself has a low surface energy, such as an organic material, a high hardness and high water-repellent surface can be formed without forming a surface water-repellent layer, as long as the above structure can be simply formed. It becomes a structure.

 The basic structure of the water-repellent film to which the present invention can be applied is porous, needle-like, column-like, groove-like, and the like. Such a basic structure includes coating, grinding, cutting, etching, and the like. Introduce smaller roughness. Even on a smooth surface that does not have a basic structure in advance, it is possible to form grooves and columns by cutting and at the same time introduce appropriate roughness to the cut surface. The effect of introducing small roughness depends on the shape of the basic structure and the location where it is introduced into the basic structure, but the transition from the peak to the valley rather than the top of the peak or the bottom of the valley, That is, when introduced into the side surface or the slope portion, the air easily gets into the valley portion and the water repellency is easily increased.

 The point of this concept is to combine two roughnesses, and the ideas of Wenzel, Cassie, Johns on Jr., R.E. And are fundamentally different. It has been known that a fractal structure is effective for a high level of water repellency.However, the concept of the present invention does not require the similarity of the structure like a fractal, and has a higher concept than a fractal. To position.

In the present invention, for example, a first concave-convex surface, which is slightly water-repellent by itself but easily obtains hardness, is formed on the surface of the substrate by a porous layer forming method, and the first concave-convex surface is formed. Form a surface with double surface roughness with a finer second uneven surface formed on top To achieve. With this structure, it is possible to form a finer air intervening layer to further increase the water repellency, and simultaneously achieve a high surface hardness by the first structure. As a method for achieving the second surface roughness for forming the second uneven surface, a method for forming by containing fine particles such as colloidal silicide force, and a method finer than the phase separation described above. It is possible to adopt a method in which a substance separated in phase with a large dispersion diameter is removed by decomposition, combustion, or sublimation to provide a finer porous structure. In addition, cutting, grinding, etching and coating are also possible. Further, such a film structure may be formed on the substrate by ion plating or the like. In order to maintain water repellency when used outdoors, a photocatalyst can be dispersed in such a film. Preferably, it is about 0.5 to 10%, and more preferably, it is dispersed in the valleys of the surface irregularities.

 (Water repellent)

 As the water repellent, it is possible to use a fluorine-silicon based water repellent or a combination thereof, but those containing fluorine are preferred because they have a large effect of lowering the surface energy. Fluoroalkylsilanes are particularly preferred. In addition, surface treatment agents such as monofluoroenoalkynolecarboxylic acid type, perfluoroalkylenosolenoic acid type, perfluoroalkylphosphoric acid type, etc., perfluoroalkyl group-containing oligomers Various fluororesins represented by polytetrafluoroethylene (PTFE), fluoride graphite, pitch fluoride, etc. can also be used.

 As for the water-repellent treatment, the wet method is most excellent in efficiency and cost as in the case of the microporous underlayer, but depending on the raw material, it may be performed by the vapor deposition method or the sputtering method.

 〔photocatalyst〕

The photocatalyst material that can be added is mainly titanium oxide, and one of titanium oxide, zinc oxide, strontium titanate, tungsten oxide, iron oxide, and copper oxide. They can be used in combination of types or multiple types. Examples of these precursors include various inorganic and organic compounds generated by heating these photocatalysts. For example, in the case of titanium oxide, titanium alkoxides such as titanium hydroxide and titanium tetrapropoxide; Titanium chloride, Titanium sulfide, Titanium bromide, Titanium iodide, Biscyclopentagenenyltitanium, Dicanolepoxide biscyclopentagenenyltitanium, Chlorobi Examples thereof include cyclopentageninoletitanium, dichlorobiscyclopentageninoletitanium, dimethinole biscyclopentene, pentageninoletitanium, and tricyclone mouth, pentageninoletitanium, and tetrabenzil titanium.

 Here, the structure of the film may be a combination of a plurality of substances as long as the size and solubility conditions are satisfied.For example, a titanium oxide photocatalyst has a property of decomposing an organic water repellent. Therefore, when a titanium oxide photocatalyst is put into a film, its concentration is adjusted to about 2 wt%, or an oxide or hydroxide of silicon, aluminum, zirconium, or a mixture thereof. It is preferable that the base material is composed of a titanium oxide photocatalyst in an amount in the range of 0.5 to 10 wt% of the base material. When the addition amount of the photocatalyst is larger than this, the photocatalytic activity increases, but the durability of the water repellent decreases, so that the contact angle decreases in a short time. [Application]

 Although a film having both practical hardness and excellent lubricity has not been obtained so far, such a film is provided by the present invention.

 The film of the present invention having both practical hardness and excellent slipperiness can be used for the exterior of vehicles such as automobiles and Shinkansen, ship bottom paints, exterior lights, kitchen and kitchen appliances, bathrooms and washrooms and their accessories, fishing nets, buoys , Dental supplies, electrical equipment, floors and exteriors of houses, entrance doors and knobs, rooftops, pools and poolsides, piers, gates, post, benches, steel towers, antennas, wires, garages, tents, umbrellas, raincoats, Lubrication of sports products and sports clothing, leather products such as helmets, shoes, etc., outdoor loudspeakers and audio equipment such as cameras, videos, paper, speakers, etc., lubrication of carpets, carpets, gasoline stands, etc. A wide range of applications can be considered, such as chemical plants such as nozzles and refineries, metal tools, nails and screws, and buckets.

 .

 Hereinafter, examples of the present invention will be described.

First, an example of a high hardness and high water-sliding film will be described. In this example, the concentrations of the three components, solvent, metal alkoxide, and polymer, were adjusted to fall within the phase separation region in the phase diagram of the three-component system shown in FIG. 1, and shown in FIG. A phase separation was formed according to the scheme. The resulting phase separation is heterogeneous, as shown in Figure 3 with alcohol (solvent). It is probable that polymer particles were dispersed in the alkoxides dissolved in each other. It is also probable that silica fine particles (for example, colloidal silica) that had formed silica sol were dispersed.

 By heat-treating the coating material in the above phase-separated state, the coating material was solidified and the polymer was removed, and water-repellent treatment was performed. As a result, the fine pores as shown in FIG. 4 were obtained. A surface (microporous surface) containing a large number of was obtained (SEM photograph). It is considered that the cross section of the micropores formed a substrate surface 2 having crater-like micropores 1 as shown in FIG.

 By adding silica sol to the irregularities on the substrate surface caused by the crater-shaped micropores 1 and containing fine particles such as colloidal silica, finer irregularities are formed on the surface irregularities. Can be raised. Such fine irregularities can also be formed by a method using phase separation, and include a phase-separation-forming substance having a finer dispersion diameter than the dispersed polymer for forming crater-like irregularities described above. It can also be formed by removing it by heat treatment.

 That is, as shown in the model diagram in FIG. 6, when only the first uneven surface 11 formed by the above-mentioned crater-like micropores is formed on the surface of the base material 10, for example, Although the slopes 12 in the respective uneven portions are relatively flat, they exhibit excellent water repellency to the droplets 13.

 On the other hand, as shown in the model diagram in FIG. 7, in addition to the first uneven surface 21 formed by the crater-shaped micropores as described above, the surface of the base material 20 is further finer. When the second uneven surface 22 is formed, the liquid droplets 23 can exhibit more excellent water repellency.

Example 1

Ethanol 20 g, tetraethylorthosilicate (TEOS) 2 g and hydrochloric acid 1.2 g were mixed for 36 hours and hydrolyzed. On the other hand, the acrylic polymer was dissolved in ethanol and the solid content was adjusted to 5.4%. Then, 4 g of this acrylic polymer-Z ethanol solution was added to the TEOS solution, and 4 g of ethanol was further added. Then, silica sol (colloidal silica) was added to the solution. A coating solution was prepared by adding 2 g. This coating solution contains an acrylic polymer in a hydrolyzed TEOS ethanol solution. A dispersed phase separation was formed.

 The phase-separated coating solution was spin-coated on Pyrex glass at 150 rotations, and the coat-dry cycle was repeated 5 times, followed by firing at 500 ° C. for 30 minutes. The thus obtained film was subjected to a water-repellent treatment by coating a fluoroalkylsilane hydrolyzed with an equivalent amount of water by a thermal CVD method to produce a water-slidable film. The resulting water-sliding membrane has a crater-like microporous structure with an average pore diameter of 1 μπι, on which finer irregularities of colloidal silica are further formed. The contact angle was 152 °, the falling angle of a 7-mg droplet was 6.5 °, and the film was a highly hard water-slidable film having a pencil hardness of H.

Comparative Example 1

 A sol obtained by dispersing 0.24 wt% of nitric acid-containing basemite in an ethanol solution of acetylacetylaluminum (2.37 wt%) was applied to Pyrex glass with a spin coat, and then applied. The cycle of baking for 20 seconds on a hot plate at 00 ° C was repeated five times to produce a transparent film. This transparent film was immersed in a 2% methanol solution of fluoroalkylsilane hydrolyzed with an equivalent amount of water for 40 minutes, and then dried at 140 ° C for 20 minutes to perform a water-repellent treatment. Thus, a water-slidable film was obtained.

 The resulting water-slidable membrane had a microporous structure with an average pore diameter of 200 nm, and its contact angle was 155 ° C, but the falling angle of a 7 mg droplet was 3 The hardness was about 0 °, and the hardness was 3 B in pencil hardness.

Comparative Example 2

 A coating agent having the same composition as the coating agent according to the above-mentioned Example 1 was prepared alone except that the acrylic polymer was not added, and film formation and water repellency were performed in the same manner as in the above-mentioned Example. Processing was performed.

 The obtained film was dense and transparent, the hardness was as high as 3 H in pencil hardness, and the contact angle was 133, but even if the film was tilted at 90 °, 7 mg droplets did not fall down. Water slip did not appear.

Example 2

Ethanol: 10 g, concentrated HC1: ◦. 6 g, tetraethyl orthosilicate: 1.0 g were mixed for 19 hours, and showed an affinity for methyl ethyl ketone (MEK). Commercial silica sol (particle size: 15 nm) was added and spin coating was performed at 1500 rpm. This was subjected to a water repellent treatment in the same manner as in Example 1 by thermal CVD. The contact angle of water was 152 °, the falling angle of a 7 mg droplet was 30 °, and the pencil hardness was 3H, which was higher than 3H. A water-repellent film was obtained. This film had a double roughness structure in which a silica sol with a primary particle size of 15 nm formed a secondary structure with a size of 600 nm. Figure 8 shows the SEM photograph.

Comparative Example 3

 Instead of the MEK-based silicasol of Example 2, an alcohol-based silicasol (particle size: 15 nm) having excellent dispersibility in ethanol was used. As a result, the contact angle was only 13 °, and the 7 mg droplet did not fall down even when tilted at 90 °.

Example 3

 Using a dicing tool and a 45-micron-thick blade on a silicon wafer, cut at both 85 mm, 105 mm, 125 mm, and 145 mm intervals at various depths from both the vertical and horizontal directions, and insert grooves into a cross. Formed structure. To this, a 2% hydrolyzed methanol solution of heptadecafluorodecyltrimethoxysilane hydrolyzed with an equivalent amount of water was coated through a gas phase at 250 ° C for 30 minutes.

The obtained roughness factor of the surface was calculated by geometrically calculating the area of the side surface of the groove, assuming that the side surface of the groove was as smooth as the silicon wafer. Figure 9 shows the change in the contact angle actually obtained with respect to the calculated roughness factor. The contact angle of the silicon wafer after the water-repellent treatment without grooves was 117 °. The solid line in the figure shows the calculated contact angle change in Wenzel's mode when roughness is introduced by cutting a groove in this water-repellent surface. When cutting at 85, 105, 125, and 145 micron intervals, the actual groove width will differ by about 5 microns.However, if a sufficiently deep groove is formed, wetting of the side surfaces of the groove will occur. The neglected solid-liquid contact area fractions are 0.21, 0.26, 0.32, and 0.44, respectively, and the calculated contact angle values in Cassie mode are 153 °, 149 °, 146 °, and 139 °, respectively. Become. In Fig. 1, there is a portion where the groove cut is shallow, that is, there is a portion where the contact angle is higher than the calculated value in Wenzel mode in the region with low roughness (low roughness factor). Is close to the angle expected from Cassie mode. Further observations of water droplets on this surface from the lateral direction show that they have already entrained air at the solid-liquid interface and that Cassie mode contributed. It was confirmed that. This is because the grooves introduced by the dicing machine are provided with roughness on the side surfaces to increase the water repellency, thereby making it easier for air to enter the grooves. This roughness is derived from a few micron diamonds and is smaller than the size of the cut grooves. That is, by introducing fine roughness on the side surface of the groove, it becomes possible to inject air into the shallow groove, and the Ca ssie mode is activated, thereby obtaining a water-repellent state. .

Example 4

 Grooves were formed vertically and horizontally on a silicon wafer with a groove width of 90 micron and a cutting interval of 125 micron at a depth of 50 micron, and water-repellent treatment was performed under the same conditions as in Example 3. Fig. 10 shows the obtained water droplets on the structure. In this structure, if the cut surface is assumed to be smooth, the roughness factor is about 1.4. In the line of the contact angle expected from the Wenzel mode shown in Fig. 9, the contact angle is about 135 °, but in the actual measurement, the contact angle deviates to the left from that line, and is a much higher value (153 °). The air was engulfed.

 As is clear from the above embodiments, according to the present invention, a highly rigid and highly water-slidable film having a controlled structure can be easily produced. It can be suitably used for various industrial products and contributes to a wide range of applications.

 Further, according to the present invention, a surface structure having excellent water repellency can be easily produced. This can be suitably used for various industrial products, and is important in applying the super water repellent technology to a wider range of applications.

 Industrial availability

Since the high-hardness / high-slidability structure of the present invention and the film thereof have both practical hardness and high-slidability, the water-repellent surface structure of the present invention further provides a desired surface area. Since the present invention can easily impart excellent water repellency, the present invention can be suitably used in various fields in which high water repellency and high water repellency are desired. Available fields include exteriors of vehicles such as automobiles and Shinkansen, bottom paint, exterior lights, kitchen and kitchenware, bathrooms and washrooms and supplies, fishing nets, buoys, dental supplies, electrical equipment, residential floors and exteriors, Entrance doors and knobs, roofs, pools and poolsides, piers, gates, bosses, benches, pylons, antennas, wires, garages, tents, umbrellas, raincoats, sports equipment and sporting clothing, helmets, shoes Leather products such as shinto, camera, video, paper, paper It covers a wide area such as outdoor loudspeakers such as cars, sound equipment, curtains, carpets, oil nozzles such as gasoline stands, chemical plants such as refineries, metal tools, nails and screws, and buckets.

Claims

Scope of demand  1. High hardness and high water-smoothness film that has both practical hardness and high water-slidability. 2. High hardness and high water-sliding membrane with the following characteristics.  Contact angle force S 140 ° or more,  The falling angle of a 7 mg droplet is 30 ° or less, and the hardness is H or more in pencil hardness. 3. High hardness characterized in that at least a part of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness. Highly slippery surface structure. 4. At least a part of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness, and at least a part of the structure is provided. A high hardness and high water-slidable surface structure, wherein a water-repellent layer is formed on at least a part of the body surface. 5. In order to form a structure in which at least a part of the surface of the basic structure having the first surface roughness has a second surface roughness smaller than the first surface roughness, cutting is performed. A method for producing a high hardness, high water-sliding surface structure, characterized in that grooves are formed in at least a part of the surface of the basic structure. 6. In order to form a structure in which at least a part of the surface of the basic structure having the first surface roughness is provided with a second surface roughness smaller than the first surface roughness, A method for producing a high-hardness and highly water-slidable surface structure, characterized in that at least a part of the surface of the structure is provided with roughness by grinding, etching or coating. 7. The surface has a first irregular surface formed with a first surface roughness and at least a second irregular surface having a second surface roughness smaller than the first surface roughness. High hardness characterized by being formed on a surface having a double surface roughness with the second uneven surface formed partially Highly water-smooth membrane. 8. The first surface roughness Ari in the range of 1 0 0 11 ₁ 11-2 ₁ 11, the second surface roughness is less than 1 0 0 nm, high hardness, high lubricity of claim 7 Aqueous membrane. 9. The method according to claim 7, wherein the first uneven surface is formed using phase separation, and the second uneven surface is formed using phase separation or contained particles. High hardness High water-sliding membrane. 10. The first uneven surface is formed using particles or aggregated particles having a larger particle diameter, and the second uneven surface uses particles or primary particles having a smaller particle diameter. 9. The high hardness and high water-sliding film according to claim 7 or 8, which is formed by: 11. The high hardness and high water-sliding film according to any one of claims 7 to 10, which is a transparent film. 12. The high hardness and high water-sliding film according to any one of claims 7 to 11, wherein a water-repellent layer is formed on at least a part of the surface. 13. The high hardness and high water-sliding film according to any one of claims 1, 2, and 7 to 12, wherein a photocatalyst is dispersed. 14. The high hardness and high water-sliding film according to any one of claims 7 to 12, wherein the photocatalyst is dispersed in a valley portion of the surface roughness. 1 5. Photocatalyst is dispersed, high hardness, high water sliding surface structure according to claim 3 or 4 ₍ 16. The high hardness and high water-sliding surface structure according to claim 3, wherein the photocatalyst is dispersed in a valley portion of the surface roughness. 17. A phase separation is formed between the raw material liquid of the membrane base material, a predetermined solvent, a substance that is removed after the raw material liquid of the membrane base material is solidified, and a sol having a primary particle diameter of 100 nm or less. An undiluted solution of a coating agent for forming a high hardness and high water-sliding film. 18. Metal alkoxide, sol having a primary particle diameter of 100 nm or less, and a substance which has a property of phase separation with these in a predetermined solvent and being removed at a temperature from room temperature to 700 ° C. A coating agent for forming a high hardness and high water-sliding film, comprising a solution in which is added to a solvent or an emulsion. 19. The coating agent according to claim 18, wherein the sol comprises a colloidal silica sol. 20. Metal alkoxide, phase-separated in a predetermined solvent and having the property of being removed at a temperature from room temperature to 700 ° C., and having a dispersion diameter in a phase-separated state of 100 nm or more. A coating material for forming a high-hardness and highly water-slidable film, comprising a solution or an emulsion obtained by adding a substance having a particle diameter of less than 100 nm to a solvent. 21. A microporous underlayer is formed by applying the coating agent according to any one of claims 18 to 20 to a substrate, and then performing a heat treatment in a temperature range from room temperature to 700 ° C. A method of forming a high hardness and high water-sliding film on the substrate by applying a water repellent to at least a part of the underlayer. 22. A coating agent for forming a high hardness and high water-sliding film, comprising particles or agglomerated particles having a particle size of 100 nm or more and particles or primary particles having a particle size of less than 100 nm. 23. The coating agent according to claim 22 is applied to a substrate, and has a first surface roughness formed by particles or aggregated particles having a particle diameter of 100 nm or more. A first uneven surface formed and a second surface roughness smaller than the first surface roughness formed by particles or primary particles having a particle diameter of less than 100 nm. No. formed on uneven surface By forming an underlayer having a surface having double surface roughness with the uneven surface of (2) and applying a water repellent to at least a part of this underlayer, high hardness and high hardness can be obtained on the substrate. A method for forming a water-slidable film. 24. A first uneven surface having a first surface roughness, and a second uneven surface formed at least partially on the first uneven surface with a second surface roughness smaller than the first surface roughness. 2. A method of producing a highly water-slidable film by subjecting at least a part of the substrate surface having a double surface roughness to the double convex surface to a water-repellent treatment. 25. The method according to claim 24, wherein the first uneven surface has a surface roughness of 100 ηηι to 2 μπι, and the second uneven surface has a surface roughness of less than 100 nm. 26. The method according to any one of claims 21 to 25, wherein a fluorine-based water repellent is applied. 27. Using the coating agent according to any one of claims 18 to 20, adjusting the state of the phase separation and adjusting the Z or the heat treatment step, thereby finally obtaining the slipperiness. A method for adjusting the slipperiness strength and / or the hardness of a membrane.