JPH10316820A - Member having extremely water-repelling surface and extremely water-repelling coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a member having extremely water-repelling surface and a coating composition for forming the same. SOLUTION: In this coating composition, a surface layer composed of silicone and a water-repelling fluororesin is formed on a surface of a base material, and the weight of the water-repelling fluororesin is 40-99% of the total weight of the surface layer. The surface layer has an extremely water-repelling property of >=150 deg. expressed in terms of a contact angle to water, and a water drop rolls down when the surface layer is inclined about 1-20 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a super-water-repellent member and a coating composition for forming the member. More particularly, the present invention relates to a member having a surface having a property of rolling down without leaving a water mark due to a slight inclination. Further, the present invention relates to a member having a surface having excellent drip-proof property. Further, the present invention relates to a member having a surface having excellent drainage properties. Further, the present invention relates to a member having a surface to which water-based dirt does not easily adhere. In addition, the present invention relates to a member having a surface having excellent running water washability. In addition, the present invention relates to a member having a surface having excellent snow prevention properties.

[0002]

2. Description of the Related Art It is often experienced that windshields, side glasses, door mirrors, fender mirrors, and road mirrors of automobiles suffer from rainfall and splashes on rainy weather, causing a large number of discrete water droplets to adhere to them, resulting in loss of visibility. Is to be done. Further, when water droplets adhere to the transmission line, the shape of the water droplets becomes a downward conical shape, so that the discharge becomes easy and leads to a power transmission loss. Also, in the winter, water drops droop like icicles,
The tip is sharp and the discharge amount is further increased. In addition, the creepage insulation of the insulator is significantly reduced due to the adhesion of water droplets. Also,
In the heat exchanger, the moisture adhering to the fins grows in the form of water droplets and is retained between the fins by capillary action, so that the water droplets become the resistance of the air flowing between the fins, thereby lowering the heat exchange efficiency. In addition, the roof in a snowfall area may be deformed due to the weight of the roof due to the large amount of snow, so that it is necessary to frequently perform heavy snow removal.
Also, in the case of an antenna in a snowfall area, icing snow sometimes causes a communication failure such as a decrease in electric field strength. Further, in the bathtub, water stains easily adhere to the apron portion, which may impair the aesthetic appearance of the bathtub used.

[0003]

The above-mentioned problems caused by the adhesion of water droplets can be solved by forming a flowable surface. According to conventional wisdom, in order to express the above-mentioned dripping properties on the surface,
It has been proposed to coat a substrate surface with a water-repellent paint such as polytetrafluoroethylene (PTFE).
However, when a water droplet is attached to the surface coated with the PTFE paint and the substrate is tilted, the water droplet does not move easily unless tilted by 60 ° or more, and the top of the water droplet moves preferentially when it moves. However, since it moves like pulling a thread, the water mark remains on the moved part after the water drop falls, and it does not have a sufficient drip-proof property and drip-proof property. This is considered to be because the surface coated with the PTFE paint exhibits only water repellency of about 100 to 120 °.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances. It is an object of the present invention to provide a coating composition exhibiting the above-mentioned water inversion by forming a coating composition.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a surface layer containing a silicone and a water-repellent fluororesin is formed on the surface of a base material. The weight of the water-repellent fluororesin relative to the total weight of the aqueous fluororesin is 50 to 99%, and the surface layer has a super-water-repellent surface of 150 ° or more in terms of a contact angle with water and 20 ° or less. A member having a super-water-repellent surface characterized by having a falling angle of water. When the weight of the water-repellent fluororesin exceeds 50% of the total weight of the silicone and the water-repellent fluororesin, the surface layer surprisingly exhibits a super-water-repellency of 150 ° or more in terms of the contact angle with water. become. Then, the water drops dropped on the surface of the member due to the slight inclination of about 20 ° or less roll down without leaving any trace of water. In other words, it is excellent in drip-proof property and drainage property. Further, the water-based dirt adhesion preventing property, running water washing property, and snow accretion preventing property are also excellent.

In a preferred embodiment of the present invention, the surface layer further contains photocatalyst particles. Also in this case, the weight of the water-repellent fluororesin relative to the total weight of the photocatalyst particles, the silicone and the water-repellent fluororesin is 50 to 50%.
It should be 99%. Then, even if the hydrophobic dirt component adheres to the surface due to the redox action of the photocatalyst, the hydrophobic dirt component is decomposed, so that the super water repellency of 150 ° or more in terms of the contact angle with water is maintained for a long time. become able to.

[0007]

Next, a specific configuration of the present invention will be described. In one embodiment of the present invention, as shown in FIG. 1, a surface layer containing silicon and a water-repellent fluororesin is formed on the surface of a substrate. In another embodiment of the present invention, as shown in FIG. 2, a surface layer containing photocatalyst particles, silicone and a water-repellent fluororesin is formed on the surface of a substrate.

[0008] Water-repellent fluororesins include polytetrafluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer.
Resins whose carbon side chains are almost fluorine can be suitably used.

The silicone has an average composition formula R _p SiO _{(4-p) / 2} (where R is a functional group comprising one or more monovalent organic groups, or a monovalent organic group). A resin represented by the following formula: X is an alkoxy group or a halogen atom, and p is a number satisfying 0 <p <2. Is available.

A photocatalyst has an energy larger than the energy gap between the conduction band and the valence band of the crystal.
A substance capable of generating conduction electrons and holes by excitation of electrons in the valence band (photoexcitation) when irradiated with light (excitation light) having a short wavelength (excitation light).
Oxides such as zeta-type titanium oxide, rutile-type titanium oxide, zinc oxide, tin oxide, ferric oxide, bismuth trioxide, tungsten trioxide and strontium titanate can be suitably used. Here, when the photocatalytic oxide is an anatase type titanium oxide, a rutile type titanium oxide, a zinc oxide, or a strontium titanate, the light source used for photoexcitation of the photocatalyst is sunlight, indoor lighting, fluorescent lamp, mercury lamp. , Incandescent lamps, xenon lamps, high-pressure sodium lamps, metal halide lamps, BLB lamps and the like can be suitably used. When the photocatalytic oxide is tin oxide, a germicidal lamp, a BLB lamp, or the like can be suitably used. To photoexcited photocatalyst, illumination of the excitation light may be at 0.001 mW / cm ² or more, but preferably that it 0.01 mW / cm ² or more, 0.
More preferably, it is 1 mW / cm ² or more.

The thickness of the surface layer is preferably set to 0.4 μm or less. Then, cloudiness due to irregular reflection of light can be prevented, and the surface layer becomes substantially transparent. Further, it is more preferable that the thickness of the surface layer be 0.2 μm or less. Then, it is possible to prevent the surface layer from being colored by light interference. Also, the thinner the surface layer, the better its transparency. Further, when the film thickness is reduced, the wear resistance of the surface layer is improved.

Metals such as Ag, Cu and Zn can be added to the surface layer. The surface layer to which the metal is added can kill bacteria and fungi attached to the surface even in a dark place.

Pt, Pd, Ru, Rh, I
A platinum group metal such as r or Os can be added.
The surface layer to which the metal is added can enhance the redox activity of the photocatalyst, and can improve the decomposability of organic contaminants and the decomposability of harmful gases and odors.

The substrate to which the present invention can be applied includes metal, ceramics, glass, plastic, wood, stone, cement, concrete, fiber, cloth, combinations thereof, and laminates thereof. It can be suitably used. The substrate to which the present invention can be applied can be applied to any substrate which is required to have a drip-proof property on a surface, a water-repellent property, an antifouling property for water-based dirt, a washing property for running water, an anti-icing snow property and the like.

[0015] As a substrate for which the surface is required to be drip-proof,
Vehicle window glass, such as side glass for automobiles, window glass for railway vehicles, windshields for vehicles, windshields for vehicles such as motorcycles, vehicle door mirrors for automobiles, back mirrors for motorcycles, etc. Vehicle lighting covers such as mirrors, automobile headlight covers, motorcycle headlight covers, instrument panel covers such as automotive instrument panel covers, architectural window glasses, roads Transparent base materials such as mirrors, outdoor lighting covers, spectacle lenses, goggles, helmet shields for motorcycles, camera lenses, camera lens covers, mirror base materials (or films to be adhered thereon) Insulation that loses visibility due to the attachment of raindrops, etc .; Insulation due to the attachment of water droplets, such as insulators (or films attached to it), reduces the electrical insulation; Fins for heat exchangers (or attached on them) Film As in, which reduces efficiency by connecting the water droplets in the air passage; and can be suitably used.

[0016] The base material which is required to have a drainable surface is a tableware, a bathtub, a toilet, a sink, a kitchen sink, a sink, a cooking range, a dishwasher, a dish dryer, a cupboard, a drain basket, a bathroom floor. Good surface drainage, such as wood, bathroom wall materials, bathroom ceiling materials, vehicle exteriors and coatings (or films attached to them), so that they dry quickly and prevent the growth of microorganisms due to water adhesion. It can be suitably used for a substrate that can be expected.

The base material required to prevent water-based dirt from adhering to the surface includes tableware, bathtubs, toilets, washbasins, kitchen sinks, sinks, cooking ranges, dishwashers, dish dryers, cupboards, drainboards, Like bathroom floor materials, bathroom wall materials, bathroom ceiling materials, aircraft, seaside buildings (or films attached to them), scales, calcium salts and magnesium salts adhere to the surface, In addition, those which show stains in appearance due to their appearance; those which adhere to an alkali salt, such as concrete-based building materials, and diffuse inward for a long time to attack the core material can be suitably used.

[0018] The base material which is required to be capable of washing the surface with running water is a building material, a building exterior, a window frame, a building window glass, a vehicle window glass, a vehicle exterior and painting, a signboard, a traffic sign, a road sound insulation wall, Sound insulation walls for railways, exteriors and coatings of garages,
Outdoor lighting covers, bridges, insulators, solar cell covers, solar water heater heat collecting covers, vinyl houses, vehicle lighting covers, line of sight guides, road reflectors, road decorative boards, railing, Outdoor components that can be cleaned by being exposed to rain, such as vehicle mirrors, outdoor surveillance cameras (or films affixed thereon); tunnel interiors and paints, building materials, building interiors, window frames, windowpanes, Housing equipment, toilets, bathtubs, washbasins, lighting fixtures, lighting covers, kitchenware, dishes, dishwashers, dish dryers, sinks, cooking ranges, kitchen hoods,
A member that can be washed with running water, such as a ventilation fan, a bathroom floor material, a bathroom wall material, a bathroom ceiling material, a kitchen sink (or a film stuck thereon), and the like can be preferably used.

As the base material which is required to have the ability to prevent icing and snow on the surface, a roofing material, an antenna, a power transmission line, an ice and snow glider, and the like can be suitably used.

In addition, the present invention can also be used for a substrate, such as an inner wall of a vacuum vessel (or a film to be adhered thereon), which requires rapid removal of moisture attached to the surface of the substrate, and a biocompatible material. There is.

Next, a method for producing an antifouling member having a surface layer containing silicone and a water-repellent fluororesin formed on the surface of a substrate will be described. The production method in this case is basically based on applying a coating composition on the surface of a substrate and curing the coating composition.

Here, the coating composition contains, as an essential component, a silicone precursor in addition to the water-repellent fluororesin.
Other catalysts such as water, ethanol, propanol, and the like, and catalysts that promote hydrolysis of silicone precursors such as hydrochloric acid, nitric acid, sulfuric acid, acetic acid, and maleic acid; tributylamine;
Catalysts for curing silicone precursors such as basic compounds such as hexylamine, acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate, and coating liquids such as silane coupling agents A surfactant or the like for improving the dispersibility of the polymer may be added.

[0023] Here silicone - The precursor emissions in the average composition formula _{R p SiX q O (4-} pq) / 2 ( wherein, R consists of one or more organic groups monovalent functional X or a functional group comprising two or more selected from a monovalent organic group and a hydrogen group, X is an alkoxy group or a halogen atom, and p and q are 0 <p <2, 0 <
a film-forming element composed of a siloxane represented by the following formula: q <4) or a general formula R _p SiX _4-p (where R is one or more monovalent organic groups) Wherein X is an alkoxy group or a halogen atom, and p is 1 or 2. A film-forming element comprising a hydrolyzable silane derivative to be
Can be suitably used.

Here, as the coating film forming element comprising the hydrolyzable silane derivative, methyltrimethoxysilane,
Methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, Phenyltributoxysilane,
Dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenyl Methyldipropoxysilane, phenylmethyldibutoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltripropoxysilane, n-propyltributoxysilane, γ-glycoxydoxypropyltrimethoxysilane, γ -Acryloxypropyltrimethoxysilane and the like can be suitably used.

The film-forming element composed of the above-mentioned siloxane includes partial hydrolysis and dehydration-condensation polymerization of the above-mentioned hydrolyzable silane derivative, or partially hydrolyzate of the above-mentioned hydrolyzable silane derivative, tetramethoxysilane and tetramethoxysilane. It can be produced by dehydration polycondensation with a partial hydrolyzate such as ethoxysilane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like.

The coating method of the coating composition includes spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge. A method such as coating can be suitably used. As a curing method, it can be carried out by polymerizing by heat treatment, standing at room temperature, ultraviolet irradiation, or the like.

[0027]

【Example】

Embodiment 1 FIG. (1) Preparation of Sample Silica sol (Nippon Synthetic Rubber, Glasca A Solution) and methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B Solution) were mixed at a solution weight ratio of 3: 1. Diluted with polytetrafluoroethylene (PT
FE) particles (Daikin Industries, Lubron L-5, average primary particle size 0.2 μm, average secondary particle size 7 μm)
After adding the zeolite titanium oxide sol (Nissan Chemical Co., TA-15), the coating solution was prepared by stirring for about 2 hours. Here, the silicone, silica and PT
The weight ratio of FE to titanium oxide is 5/6/66/33, and the solid content concentration is 10%. Next, 45mm x 95
mm glazed tile base material (Tochiki Koki exterior wall tile, A
B02E11), the above-mentioned coating liquid was supplied with a diameter of 8 mm.
Is applied by a spray coating method using a spray gun (Meiji Kikai Seisakusho, FS-G08R), cured at 200 ° C. for 15 minutes, and PTFE and titanium oxide particles are dispersed in the silicone coating film. The # 1 sample was obtained by forming the surface layer thus prepared. The coating weight when dried was 2.67 mg.
/ Cm ² , and the film thickness was about 5 μm. Since the average secondary particle size of PTFE is larger than the film thickness, PTF
E is considered to be partially exposed to the outside air on the coating film surface. On the other hand, silica sol (Nippon Synthetic Rubber, Glasca A liquid)
And methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) so that the weight ratio of the solution becomes 3: 1.
-Polytetrafluoroethylene (PTFE) particles diluted with propanol (Daikin Industries, Lubron L-
5, average primary particle size is 0.2 μm, average secondary particle size is 7 μm
After addition of m), the coating solution was prepared by stirring for about 2 hours. Here, the weight ratio of silicone, silica and PTFE in this mixture is 20/24/66,
The solids concentration is 10%. Next, 45mm x 95mm
On glazed tile base material (exterior wall tile made by TOTO, AB0
2E11), the above coating solution was applied by a spray coating method using a spray gun having a diameter of 8 mm (Meiji Kikai Seisakusho, FS-G08R), and then applied at 200 ° C. for 15 minutes.
After a minute curing treatment, a surface layer in which PTFE was dispersed in the silicone coating film was formed to obtain a # 2 sample. The coating weight at the time of drying was 2.99 mg / cm ² , and the film thickness was about 5 μm. Since the average secondary particle size of PTFE is larger than the film thickness, it is considered that PTFE is partially exposed to the outside air on the coating film surface. For comparison, 4
A 5 mm x 95 mm glazed tile (exterior wall tile made by TOTO CORPORATION, AB02E11) and a PTFE plate were also prepared. (2) Evaluation The # 1 and # 2 samples and the comparative sample were evaluated for the contact angle with water on the surface, the presence / absence of water droplets falling at a 20 ° inclination, and the oil decomposition performance. The contact angle of the surface with water is determined by a contact angle measuring device (Kyowa Interface Science CA-X150).
The value was evaluated after 0 seconds. As a result, in the PTFE plate, 11
In contrast to 0 °, the # 1 sample showed 156 ° and the # 2 sample showed 155 °, indicating super water repellency. Add 20 more samples
゜ When tilted, water drops fell on the # 1 and # 2 samples, leaving no trace of water, but did not fall on the PTFE plate. Next, in order to examine the effect of maintaining the surface cleanliness by adding the photocatalyst particles, a decomposition test of the oil intentionally attached to the surface was performed. That is, about 10 mg of trioleic acid glyceride was uniformly applied on the # 1 sample, the # 2 sample and the glazed tile over the entire surface of the sample, and the sealed relative humidity was 90 RH.
% From the outside of the container using an ultraviolet light source (Sankyo Electric, Black Light Bull- (BLB) fluorescent lamp) from the outside of the container for 4 days so that the intensity at a wavelength of 365 nm becomes 1 mW / cm ² on the surface of the coating film. Irradiation with ultraviolet light was performed, and the weight loss of the applied glyceride trioleate was measured. As a result, no change was observed in the weight of oleic acid glyceride in the # 2 sample and the glazed tile, whereas the # 1 sample was completely decomposed to 0 mg. Therefore, it was confirmed that the surface cleanliness can be maintained by adding the photocatalyst particles.

Embodiment 2 FIG. (1) Preparation of Sample Silica sol (Nippon Synthetic Rubber, Glasca A Solution) and methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B Solution) were mixed at a solution weight ratio of 3: 1. Diluted with polytetrafluoroethylene (PT
FE) particles (Daikin Industries, Lubron L-5, average primary particle size 0.2 μm, average secondary particle size 7 μm)
A coating solution was prepared by stirring for about 2 hours. Here, the weight ratio of silicone, silica and PTFE in this coating solution was 15/18/77 (# 3A sample), 10/12/33 (# 4A sample), and 5/6/11.
(# 5A sample), 15/18/22 (# 6A sample)
And solid content concentration is 10%. Next, 45m
The above coating liquid (# 3) was placed on a glazed tile base material of mx 95 mm (exterior wall tile made by TOTO CORPORATION, AB02E11).
A to # 6A samples) were applied by a spray coating method using a spray gun having a diameter of 8 mm (FS-G08R, Meiji Kikai Seisakusho), cured at 200 ° C. for 15 minutes,
Forming a surface layer in which TFE was dispersed in a silicone coating film, samples # 3B to # 6B were obtained. The coating weight at the time of drying was 2.99 mg / cm ² and the film thickness was about 5 μm.
m. Since the average secondary particle size of PTFE is larger than the film thickness, it is considered that PTFE is partially exposed to the outside air on the coating film surface. (2) Evaluation The # 3B to # 6B samples were evaluated for the contact angle with water on the surface and the presence / absence of falling of water droplets at a 20 ° inclination. The contact angle of the surface with water is 155 ° for the # 3B sample and # 4B
The samples had 155 °, the # 5B sample had 150 °, and the # 6B sample had 135 °, and the # 3B to # 5B samples having a fluorine resin content of more than 40% exhibited super water repellency of more than 150 °. When the sample is further tilted by 20 °, # 3B ~
In the # 5B sample, water droplets fell and no trace of water remained.

[0029]

According to the present invention, since the surface of the member becomes super-water repellent, it has the property of rolling down without leaving a trace of water due to a slight inclination. It can be expected to be excellent in water drainage property, and further excellent in water-based stain adhesion prevention property, running water washing property and snow accumulation prevention property.

[Brief description of the drawings]

FIG. 1 is a diagram showing a surface structure of a member according to the present invention.

FIG. 2 is a diagram showing another surface structure of the member according to the present invention.

Claims (6)

[Claims] 1. A surface layer containing a silicone and a water-repellent fluororesin is formed on the surface of a base material, and the weight of the water-repellent fluororesin is 40 to 9 with respect to the total weight of the surface layer.
9%, and the surface layer has a super-water-repellent surface of 150 ° or more in terms of a contact angle with water, and
A member having a super-water-repellent surface, characterized in that water falls due to an inclination of about 0 °. 2. A surface layer containing a silicone and a water-repellent fluororesin is formed on the surface of a substrate, and the weight of the water-repellent fluororesin is 50 to 9 with respect to the total weight of the surface layer.
9%, and the surface layer has a super-water-repellent surface of 150 ° or more in terms of a contact angle with water, and
A member having a super-water-repellent surface, characterized in that water falls due to an inclination of about 0 °. 3. A surface layer containing photocatalyst particles, silicone and a water-repellent fluororesin is formed on the surface of the substrate, and the weight of the water-repellent fluororesin is 40 to 99 with respect to the total weight of the surface layer. %, And the surface layer has a super-water-repellent surface of 150 ° or more in terms of a contact angle with water, and water falls down by an inclination of about 1 to 20 °. A member having a super water repellent surface. 4. A surface layer containing photocatalyst particles, silicone and a water-repellent fluororesin is formed on the surface of the base material, and the weight of the water-repellent fluororesin is 50 to 99 with respect to the total weight of the surface layer. %, And the surface layer has a super-water-repellent surface of 150 ° or more in terms of a contact angle with water, and water falls down by an inclination of about 1 to 20 °. A member having a super water repellent surface. 5. (a) Average composition formula R _p SiX _q O _{(4-pq) / 2} (where R is a functional group comprising one or more monovalent organic groups, or a monovalent organic group) X is an alkoxy group or a halogen atom, and p and q are 0 <p <2, 0 <
q <4). (b) water-repellent fluorine per 1 part by weight of a film-forming element made of a siloxane represented by the following formula: It contains 1 to 99 parts by weight of a resin, and its surface is converted to a contact angle with water at the time of forming a coating film by 150.
A super-water-repellent coating composition having a super-water-repellent surface of not less than ゜ and a falling angle of water of not more than 20 ゜. 6. A compound represented by the general formula: R _p SiX _4-p (wherein R is a functional group comprising one or more monovalent organic groups, or a monovalent organic group and a hydrogen group. X is an alkoxy group or a halogen atom, and p is 1 or 2), and is a coating film forming element comprising a hydrolyzable silane derivative represented by the following formula: (B) 1 to 99 parts by weight of a water-repellent fluororesin, and 1 part by weight of a water-repellent fluororesin to form a silicone resin film when cured. Converted to 150
A super-water-repellent coating composition having a super-water-repellent surface of not less than ゜ and a falling angle of water of not more than 20 ゜.