JP2007291314A - Coating film having water slipping property and process for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a coating film high in the property of making a waterdrop slip down a surface of the coating film on a substrate in a simple and convenient method and at a low cost. <P>SOLUTION: The coating film having a high water slipping property formed on a substrate comprises a hydrocarbon polymer and has a rate of waterdrop slipping down of greater than 0.5 cm/sec defined as follows: the rate of waterdrop slipping down is calculated from the measurement of the time which it takes a waterdrop to move down 90 mm when the waterdrop is formed by dropping 50 μL of distilled water onto a surface of a sample laid with the inclination at 15 degrees to the horizontal under the conditions of a temperature of 20±5°C and a relative humidity of 50±10%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating film having high water slidability and a method for producing the same.

  2. Description of the Related Art Conventionally, a technique for imparting water repellency by chemical treatment such as coating a solid surface with a fluorine resin or a silicon resin is well known. On the other hand, not only such water repellency but also a technique that pays attention to water droplet sliding on the substrate surface has been known. For example, Patent Document 1 discloses a mixture of a hydrophilic organosilicon compound having a hydrophilic group (methanesulfonyl group) and a hydrophobic organosilicon compound, and Patent Document 2 discloses a silicone compound substrate. A technique is described in which the amount of slippage of water droplets is improved by increasing the amount of introduction to the surface.

In Patent Document 3, the surface of a substrate is treated with a surface treatment agent containing a water repellent binder resin such as a fluororesin, a dispersant such as a water and oil repellent, and particles of low heat capacity such as carbon black. Describes that a high water-sliding film can be obtained.
JP 2000-8026 A JP 2000-144056 A JP 2005-132919 A

On the other hand, techniques for imparting water repellency with non-fluorine and non-silicone materials have also been proposed.
In Patent Document 4 (Japanese Patent Laid-Open No. 2005-53104), a super-water-repellent surface having a three-dimensional continuous structure network skeleton structure is made of a polymer material, but the surface has a micro uneven structure (μm order). ) Achieves super water repellency, and there is a problem that durability cannot be maintained. Moreover, it is insufficient from the viewpoint of water slidability.

Patent document 5 (Unexamined-Japanese-Patent No. 2004-155936) is related with the resin surface for waterproof materials excellent in secondary adhesiveness. It is characterized by the fact that wax-like hydrocarbons essential for preparation cover the surface and cause a polymerization reaction in the lower layer. Similarly, it is used as a component essential for surface formation, and forms polyoxyls that form micelles with the wax. Since the hydrophilic functional group of ethylene alkylphenyl ether exists on the surface as a single layer, it is insufficient from the viewpoint of water slidability.
Patent Document 6 (Japanese Patent Laid-Open No. 2004-359834) uses a copolymer containing (meth) acrylate having a water-repellent group containing no silicone and fluorine as an essential copolymer component to form a stain-resistant surface. is doing.

  In Patent Document 7 (Japanese Patent Laid-Open No. 2005-325338), a contamination-preventing surface is created using a non-fluorine polymer and colloidal silica, but irregularities are generated on the surface because of the introduction of inorganic solids. Therefore, there is a problem that the sliding property is insufficient and the pot life is short.

  In view of the above-described conventional technology, the present invention provides a new technology for forming a highly slippery coating, which is different from the conventional method for forming a water slippery surface. The present invention further provides a technique for easily obtaining an excellent water sliding surface using an inexpensive and general-purpose material.

As a result of intensive studies, the present inventors have found that it is possible to obtain a very high water-sliding film by forming a surface on a substrate using a hydrocarbon polymer, and have reached the present invention. That is, the configuration of the present invention is as follows.
(1) A water-sliding film formed on a substrate, which contains a hydrocarbon polymer and has a sliding speed defined below that is greater than 0.5 cm / second.
Sliding speed: In an environment with a temperature of 20 ± 5 ° C. and a relative humidity of 50 ± 10%, 50 μl of distilled water is dropped on a sample placed at an inclination of 15 degrees with respect to the horizontal plane to form water droplets. The travel time was measured and calculated.

(2) The highly lubricious coating film according to (1), wherein the hydrocarbon polymer is polystyrene.
(3) The water-slidable coating film as described in (1) or (2) above, wherein the hydrocarbon polymer is contained in an amount of 50% by mass or more based on the total polymer.
(4) The water-slidable coating film according to any one of (1) to (3), wherein the hydrophilic polymer is contained in an amount of 15% by mass or less based on the hydrocarbon polymer.

(5) The water-slidable coating according to (1), wherein the coating has a surface roughness Ra of 100 nm or less.
(6) The water slidable coating film according to any one of the above (1) to (5), which is obtained by coating a coating composition containing a hydrocarbon polymer and a solvent on a substrate.
(7) The water-slidable coating film according to any one of the above (1) to (5), which is obtained by coating a coating composition containing polystyrene and a solvent on a substrate.
(8) The water-slidable coating according to (6) or (7), wherein the solvent is an aromatic solvent.
(9) The method for producing a water-slidable coating according to any one of the above (1) to (7), wherein a coating composition containing polystyrene and a solvent is coated on a substrate.

  The sliding speed of the present invention is “a temperature drop of 20 ± 5 ° C. and a relative humidity of 50 ± 10% is formed by dropping 50 μl of distilled water on a sample placed at an inclination of 15 degrees with respect to a horizontal plane to form water droplets. The time required for the water droplets to move 90 mm was measured and calculated as (sliding speed) = (moving distance / hour) The sliding speed of the large coating film according to the present invention is 0.5 cm / second or more. , Preferably 0.7 cm / second or more, more preferably 1.0 cm / second or more.

  According to the present invention, a highly water-slidable film having a sliding speed of 0.5 cm / second or more can be obtained simply and inexpensively.

  The highly lubricious coating film of the present invention is formed on a substrate. The substrate is not particularly limited, and any substrate made of an inorganic substance or an organic substance such as a polymer can be used. As the base material made of inorganic material, glass, silicon, aluminum, stainless steel, metal such as gold, silver, zinc, copper, etc., and metal oxide such as ITO, tin oxide, alumina, titanium oxide, etc. are provided on the surface. Can be used.

  Polymer substrates include polyethylene, polypropylene, polystyrene, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polycarbonate, polyvinyl acetal, polyurethane, epoxy resin, polyester A substrate made of a resin, an acrylic resin, or a polyimide resin can be used.

  These polymer base materials are pre-treated such as corona treatment, plasma treatment, etc., or have fine irregularities on the surface in order to improve the adhesion with a highly lubricious film provided on the substrate. It may be. The shape of the substrate is not particularly limited.

The highly water-slidable coating film of the present invention is characterized by containing a hydrocarbon polymer.
The hydrocarbon polymer preferably has a mass content of carbon and hydrogen of 70% or more, more preferably 90% or more. For example, polystyrene, polyethylene, polypropylene, polybutadiene or a mixture thereof can be used.
Among these, a polymer containing an aromatic hydrocarbon is preferable, and a polystyrene-based polymer is particularly preferable.
The molecular weight of the polymer is preferably from 1,000 to 1,000,000, and the molecular weight is more preferably from 5,000 to 500,000 from the viewpoints of solubility in a solvent and film formation.

  In the film of the present invention, other polymers than the above hydrocarbon polymer may be contained for improving the film strength and other physical properties. However, in order to obtain a good water-sliding surface, the hydrocarbon polymer is preferably contained in an amount of 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more in the total polymer of the film. is there.

In addition to the above hydrocarbon polymer, it is possible to remarkably improve the water slidability by adding a hydrophilic polymer to 15% by mass or less based on the hydrocarbon polymer. Here, the hydrophilic polymer in the present invention refers to a polymer having a relatively small contact angle as compared with the hydrocarbon polymer.
Specific examples of hydrophilic polymers include poly (meth) acrylates such as polymethyl methacrylate, polybutyl methacrylate, and polymethacrylic acid, polyesters such as polylactic acid and PET, or polyimide, polysulfone, polyamide, polyketone, and the like. The polymer is preferred.
These hydrophilic polymers are more preferably added in an amount of 15% by mass or less, and particularly preferably 10% by mass to 0.01% by mass with respect to the hydrocarbon polymer. By making the addition amount of the hydrophilic polymer within the above range, a sliding effect can be obtained while maintaining the properties of the hydrocarbon polymer.
The molecular weight of the hydrophilic polymer is preferably 2500 to 50000, more preferably 5000 to 30000 from the viewpoint of solubility.

In addition, low molecular compounds other than polymers may be added to improve film physical properties, such as alkylphenol compounds such as 4-butyl-2-methylphenol and methylenebis (2,4-dimethylphenol), and stearamide. Amide compounds such as palmitic acid amide, ether compounds such as diethylene glycol dimethyl ether, and thioether compounds such as dibutyl thioether and phenyloctyl thioether.
These low molecular compounds are preferably added at a concentration of 1% by weight or less as a solid content concentration in order to improve the physical properties of the film without impairing the water slidability.

The film having a large water-sliding property of the present invention is preferably a fine uneven layer having a water-repellent treatment on the surface, and the average surface roughness Ra of the fine uneven layer is preferably 100 nm or less.
Here, the “average roughness Ra” is a parameter that is provided as a standard in a normal surface roughness meter, and can be easily measured by a normal surface roughness meter. The “average roughness Ra” generally means the height of the middle line when the standard deviation of the distance from the low part to the top part of the minute unevenness is taken. The scattering of light usually becomes remarkable from the size of about 1/10 to 1/5 of the wavelength, and the wavelength of visible light is mainly about 400 to 800 nm, so that transparency is ensured in this wavelength region. Therefore, it is preferable to suppress the average roughness (Ra) of the surface of the substance to 100 nm or less. More preferably, it is 50 nm or less.

  There is no particular limitation on the method for forming a coating film containing a hydrocarbon polymer and containing a large amount of water on the substrate, and examples thereof include coating, vapor deposition, sticking, and pressure bonding. Preferably, a coating solution containing a hydrocarbon polymer is prepared, and the coating solution is applied and dried on a substrate.

As a coating method, known coating means such as dipping, spraying, spin coating and curtain coating can be used.
The coating solution can be used by diluting with an organic solvent or the like, if necessary, such as a coating method. As the organic solvent to be used, any method may be used, as long as the compound contained in the coating solution is uniformly dissolved, or it may be used alone or in combination. For example, primary alcohols such as methanol, ethanol, normal propyl alcohol, normal butyl alcohol, secondary alcohols such as isopropyl alcohol and isobutyl alcohol, tertiary alcohols such as tertiary butyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono Glycols such as ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, esters such as methyl acetate and ethyl acetate, ethers such as diethyl ether, diisopropyl ether and di-tert-butyl ether, acetone, methyl ethyl ketone, cyclohexanone, etc. Common solvents such as ketones, aromatic solvents such as toluene, xylene, and mesitylene It is below.

  In order to improve the adhesion to the substrate, it is preferable to remove impurities on the substrate and remove stains on the substrate surface before forming the high water-sliding film containing the hydrocarbon polymer. The removal method is not particularly limited, and examples thereof include gas spraying, alkali cleaning, UV / ozone treatment, and plasma treatment. Among these, alkali cleaning, UV / ozone treatment, and plasma treatment are preferable because sufficient effects are obtained and the operation is simple.

  The highly water-slidable coating of the present invention can easily spill minute water droplets, and in particular, it may cause damage due to icing or snowing, decrease its function, or cause injury to humans. It can be effectively applied to certain instruments, devices, equipment, buildings, and parts thereof. Specifically, outdoor telecommunication equipment such as various antennas, communication cables, window glass for ships and trains, transport vehicles such as decks, steps, exteriors, buildings such as roof tiles, tiles, window glass, Other examples include a solar panel cover.

  Examples of the present invention are illustrated below, but the present invention is not limited to these examples.

Example 1
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by weight polystyrene solution in toluene was applied by spin coating (700 rpm for 20 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 20 minutes.
When this substrate was observed with an AFM, it was found that the surface of the micro unevenness made of polystyrene was uniformly distributed, and when the height of the micro unevenness was measured, the Ra value was about 10 nm.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.0 seconds.

Example 2
A substrate was prepared by the method of Example 1 except that a 1% by mass (polystyrene / polymethyl methacrylate = 3: 1 mass ratio) toluene solution was used instead of the 1% by mass polystyrene toluene solution of Example 1.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.2 seconds.

Example 3
A substrate was prepared by the method of Example 1 except that a 1% by mass (polystyrene / polymethyl methacrylate = 1: 1 mass ratio) toluene solution was used instead of the 1% by mass polystyrene toluene solution of Example 1.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.2 seconds.

Example 4
A substrate was prepared by the method of Example 1 except that a silicon substrate was used instead of the glass substrate of Example 1.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.0 seconds.

Comparative Example 1
A substrate was prepared by the method of Example 1 except that instead of the 1% by weight polystyrene toluene solution of Example 1, a 1% by weight polymethyl methacrylate-methyl ethyl ketone solution was used.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from the height of 1 cm onto the upper end of the substrate, and stopped halfway and did not fall to the opposite end.

Comparative Example 2
A substrate was prepared by the method of Example 1 except that a 1% by mass (polystyrene / polymethyl methacrylate = 1: 3 mass ratio) toluene solution was used instead of the 1% by mass polystyrene toluene solution of Example 1.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from the height of 1 cm onto the upper end of the substrate, and stopped halfway and did not fall to the opposite end.
Comparative Example 3
A polytetrafluoroethylene sheet was cut into 5 cm square, washed with alkali, and dried at 100 ° C. for 2 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from the height of 1 cm onto the upper end of the substrate, and stopped halfway and did not fall to the opposite end.

Comparative Example 4
A 1.0 mm-thick silicon polymer sheet prepared with SILGARD 184 (Toray Dow Corning) was cut into 5 cm square and adhered onto a glass substrate.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from the height of 1 cm onto the upper end of the substrate, and stopped halfway and did not fall to the opposite end.

Example 5
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (manufactured by Nippon Laser Electronics Co., Ltd., NL-UV253) for 5 minutes. A 1% by weight (polymethyl methacrylate / polystyrene = 1/8 (mass ratio)) toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.0 seconds.

Example 6
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by mass (polymethyl methacrylate / polystyrene = 1/128 (mass ratio)) toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.2 seconds.

Example 7
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by weight (polymethyl methacrylate / polystyrene = 1/2000 (mass ratio)) toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.1 seconds.

Example 8
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by weight (polymethyl methacrylate / polystyrene = 1/33000 (mass ratio)) toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it was 3.3 seconds.

Comparative Example 5
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by weight polystyrene toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from a height of 1 cm onto the upper edge of the substrate. When the falling time until falling to the opposite end was measured 5 times, it did not fall to the opposite end.

Comparative Example 6
A 10 cm square (0.7 mm thick) white plate glass was exposed to a UV ozone cleaner (NL-UV253, manufactured by Nippon Laser Electronics Co., Ltd.) for 5 minutes. A 1% by mass (polymethyl methacrylate / polystyrene = 8/1 (mass ratio)) toluene solution was applied by spin coating (3000 rpm for 30 seconds), and then dried at room temperature for 10 minutes and at 100 ° C. for 30 minutes.
The prepared substrate was tilted at 15 °, and 50 μl of water was dropped from the height of 1 cm onto the upper edge of the substrate, and the droplet did not fall after dropping on the substrate.

Claims (9)

A water-slidable coating formed on a substrate, comprising a hydrocarbon polymer and characterized in that the sliding speed defined below is greater than 0.5 cm / sec.
Sliding speed: In an environment with a temperature of 20 ± 5 ° C. and a relative humidity of 50 ± 10%, 50 μl of distilled water is dropped on a sample placed at an inclination of 15 degrees with respect to the horizontal plane to form water droplets. The travel time was measured and calculated.   The water-slidable coating according to claim 1, wherein the hydrocarbon polymer is polystyrene.   3. The water-slidable coating according to claim 1, wherein the hydrocarbon polymer is contained in an amount of 50% by mass or more based on the total polymer.   The water-slidable coating film according to any one of claims 1 to 3, wherein the hydrophilic polymer is contained in an amount of 15% by mass or less based on the hydrocarbon polymer.   2. The water-slidable coating according to claim 1, wherein the coating has a surface roughness Ra of 100 nm or less.   The water-slidable coating film according to any one of claims 1 to 5, obtained by coating a coating composition containing a hydrocarbon polymer and a solvent on a substrate.   The water-slidable coating film according to any one of claims 1 to 5, which is obtained by coating a coating composition containing polystyrene and a solvent on a substrate.   The water-slidable coating according to claim 6 or 7, wherein the solvent is an aromatic solvent.   The method for producing a water-slidable coating film according to any one of claims 1 to 7, wherein a coating composition containing polystyrene and a solvent is coated on a substrate.