JPH10130037A - Vehicle window glass having stain proofing property in combination with water drop-sticking preventing property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle window glass having a surface hardly being stained, hardly sticking waterdrop and thus improved in the safety operability of vehicle. SOLUTION: In the vehicle window glass, a substantially transparent surface layer containing a photocatalytic oxide particle, a silicone and a water repellent fluororesin or a substantially transparent surface layer containing the photocatalytic oxide particle, an amorphous silica and the water repellent fluororesin is formed at least on the outer surface of the window glass. And the contact angle of the surface with water is controlled to >=90 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle glass which can be used for a windshield, a side glass and the like of an automobile.

[0002]

2. Description of the Related Art When a vehicle glass, which can be used as a windshield or a side glass of an automobile, receives rain or splashes in the rain, it is often experienced that a large number of discrete water droplets adhere to the surface and lose visibility. Is Rukoto. Loss of visibility in this way hinders safe driving of the vehicle. Therefore, windshields of automobiles and other vehicles generally incorporate a wiper, a defrost device, and a heater, thereby ensuring visibility in rainy weather.

[0003] Vehicle glass, which can be used as a windshield or a side glass of an automobile, is contaminated by soot in exhaust gas, abrasion powder of tires, and dust soaring from a road surface or the ground while the vehicle is running on a road with heavy traffic. . If the vehicle glass becomes dirty, the translucency is reduced, which also hinders safe driving of the vehicle.

[0004]

However, it is difficult to say that only the wiper, the defrost device and the heater are enough to secure visibility in rainy weather. Further, frequent cleaning is required to prevent the vehicle glass from being stained and the light transmittance being reduced. Therefore, in the present invention, in view of the above circumstances,
An object of the present invention is to provide a vehicle window glass having a surface that is hardly soiled and hardly adheres to water droplets, thereby improving the safe driving performance of the vehicle.

[0005]

According to the present invention, in order to solve the above-mentioned problems, at least the outer surface of a window glass substrate is substantially transparent containing photocatalytic oxide particles, silicone and a water-repellent fluororesin. The present invention provides a vehicle windowpane having both an antifouling property and an anti-waterdrop adhesion property, characterized in that a smooth surface layer is formed and the surface of the layer has a contact angle with water of 90 ° or more. By forming a surface layer containing photocatalytic oxide particles, silicone and a water-repellent fluororesin, the organic group bonded to the silicon atom in the silicone molecule by photocatalysis when the photocatalyst is photoexcited. Is at least partially substituted with a hydroxyl group to exhibit hydrophilicity, and both the silicone-exposed hydrophilic part exposed to the outside air and the water-repellent part exposed to the water-repellent fluororesin are exposed to the surface. A microscopically dispersed structure results. Furthermore, the presence of the photocatalyst allows the silicone in which the organic group bonded to the silicon atom in the silicone molecule is at least partially substituted with a hydroxyl group in response to the photoexcitation of the photocatalyst to remain permanently hydrophilic. The structure in which both the portion exhibiting the property and the portion exhibiting the water repellency are microscopically dispersed on the surface is maintained. In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic adherent that easily adapts to the hydrophilic surface does not adapt to the adjacent water-repellent portion. Conversely, hydrophobic deposits that are easily adapted to the water-repellent surface do not adapt to adjacent hydrophilic portions. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state. Further, by setting the contact angle with water to 90 ° or more, water droplets hardly adhere. Therefore, it is possible to form a surface that is less likely to be soiled and to which water droplets are less likely to adhere, thereby improving the safe driving performance of the vehicle.

A substantially transparent surface layer containing photocatalytic oxide particles, amorphous silica and a water-repellent fluororesin is formed on at least the outer surface of the window glass substrate, and the surface of the layer is made of water. A vehicle window glass having both an antifouling property and an anti-waterdrop property, characterized in that the contact angle with the glass is 90 ° or more. By forming a surface layer containing photocatalytic oxide particles, amorphous silica, and a water-repellent fluororesin, the amorphous silica in the surface layer is exposed to the outside and exhibits a hydrophilic portion, Both of the water-repellent portions of the water-repellent fluororesin exposed to the outside air are microscopically dispersed on the surface. Further, the presence of the photocatalyst allows the amorphous silica to maintain its hydrophilicity permanently in response to the photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically visible on the surface. The distributed structure is maintained. In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic adherent that easily adapts to the hydrophilic surface does not adapt to the adjacent water-repellent portion. Conversely, hydrophobic deposits that are easily adapted to the water-repellent surface do not adapt to adjacent hydrophilic portions. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state. Further, by setting the contact angle with water to 90 ° or more, water droplets hardly adhere. Therefore, it is possible to form a surface that is less likely to be soiled and to which water droplets are less likely to adhere, thereby improving the safe driving performance of the vehicle.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of a vehicle window glass according to the present invention, as shown in FIG. 1, a surface of a window glass substrate contains photocatalyst particles, silicone, and a water-repellent fluororesin. A layer is formed and the surface has a contact angle of 90 ° or more with water. When light capable of photo-exciting the photocatalyst is irradiated to FIG. 1, at least a part of the silicone exposed to the outside air becomes at least partially converted into a hydroxyl group by an organic group bonded to a silicon atom in the silicone molecule by a photocatalytic action. As a result of the substitution, it became hydrophilic, and both the silicone-exposed hydrophilic part exposed to the outside air and the water-repellent fluororesin exposed to the air and the water-repellent part were microscopically dispersed on the surface. Structure.
Further, the presence of the photocatalyst allows the amorphous silica to maintain its hydrophilicity permanently in response to the photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically visible on the surface. The distributed structure is maintained. Therefore, by adopting such a structure, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface.
The surface is kept clean. Further, by setting the contact angle with water to 90 ° or more, water droplets hardly adhere. Therefore, it is possible to form a surface that is less likely to be soiled and to which water droplets are less likely to adhere, thereby improving the safe driving performance of the vehicle.

In another embodiment of the present invention, as shown in FIG. 2, a surface layer containing photocatalyst particles, amorphous silica, and a water-repellent fluororesin is formed on the surface of the window glass substrate. And the contact angle of the surface with water is 90 ° or more. The photocatalyst particles, the amorphous silica, and the surface layer containing the water-repellent fluororesin are formed so that the amorphous silica in the surface layer is exposed to the outside air and exhibits a hydrophilic property. Both of the water-repellent portions where the resin is exposed to the outside air are microscopically dispersed on the surface. Further, the presence of the photocatalyst allows the amorphous silica to maintain its hydrophilicity permanently in response to the photoexcitation of the photocatalyst, so that both the hydrophilic portion and the water-repellent portion are microscopically visible on the surface. The distributed structure is maintained. Therefore, by adopting such a structure, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state. Further, by setting the contact angle with water to 90 ° or more, water droplets hardly adhere. Therefore, it is possible to form a surface that is less likely to be soiled and to which water droplets are less likely to adhere, thereby improving the safe driving performance of the vehicle.

A photocatalyst is a device that emits light (excitation light) having an energy (ie, shorter wavelength) larger than the energy gap between the conduction band and the valence band of a crystal when the electrons in the valence band are irradiated. A substance capable of generating conduction electrons and holes by excitation (photoexcitation). Photocatalytic oxides include, for example, anatase-type titanium oxide, rutile-type titanium oxide, zinc oxide, tin oxide, and ferric oxide. And oxides such as bismuth trioxide, tungsten trioxide and strontium titanate. As a light source used for photoexcitation of the photocatalyst, a light source in a traveling environment such as sunlight or a street lamp may be used, or a light source capable of irradiating excitation light may be used as an incidental facility or a portable facility. The light source used in that case, for example, a fluorescent lamp, an incandescent lamp, a mercury lamp,
A germicidal lamp or the like can be suitably used. By photoexcitation of photocatalyst,
In order for the surface of the base material to be highly hydrophilic, the illuminance of the excitation light may be 0.001 mW / cm ² or more.
It is preferably at least mW / cm ^2, more preferably at least 0.1 mW / cm ² .

As the vehicle glass substrate, a transparent substrate such as glass, double-glazed glass, tempered glass, and transparent plastic, and a transparent body provided with a transparent hard coat thereon can be suitably used.

An intermediate layer may be provided between the vehicle glass substrate and the surface layer for the purpose of improving adhesion to the substrate.

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) Wherein X is an alkoxy group or a halogen atom, and p is a number satisfying 0 <p <2). it can.

As the water-repellent fluororesin, polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer and the like can be suitably used.

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.

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

Here, the coating composition contains, as essential components, a silicone precursor in addition to the photocatalyst particles and the water-repellent fluororesin, and a solvent such as water, ethanol, propanol, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, or the like. Catalysts that promote the hydrolysis of silicone precursors such as maleic acid, and basic compounds such as tributylamine and hexylamine,
Catalysts for curing silicone precursors, such as acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate, and surfactants, such as silane coupling agents, that improve the dispersibility of coating liquids can be added. Good.

Here, the precursor of the silicone includes an 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, it is a functional group consisting of two or more kinds 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 siloxane includes partial hydrolysis and dehydration-condensation polymerization of the hydrolyzable silane derivative, or partial hydrolyzate of the hydrolyzable silane derivative, tetramethoxysilane, tetramethoxysilane and tetramethoxysilane. It can be produced by dehydration polycondensation with a partial hydrolyzate such as ethoxysilane, tetrapropoxysilane, tetrabutoxysilane, diethoxydimethoxysilane and the like.

As the method for applying the coating composition, methods such as spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge 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.

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

Here, the coating composition contains silica particles or a silica precursor in addition to photocatalyst particles and water-repellent fluororesin as essential components, and in addition, a solvent such as water, ethanol, propanol, hydrochloric acid, nitric acid, and sulfuric acid. , Acetic acid, catalysts that promote the hydrolysis of silica precursors such as maleic acid, and silica such as basic compounds such as tributylamine and hexylamine, and acidic compounds such as aluminum triisopropoxide and tetraisopropyl titanate. A catalyst for curing the precursor or a surfactant for improving the dispersibility of the coating liquid such as a silane coupling agent may be added.

The silicone precursor used herein has an average composition formula of SiX _q O _{(4-q) / 2} (where X is an alkoxy group or a halogen atom, and q satisfies 0 <q <4). A film-forming element comprising a silicate represented by the general formula:
₄ (wherein R is a functional group composed of one or more monovalent organic groups, or a functional group composed of two or more monovalent organic groups and hydrogen groups, and X is An alkoxy group,
Alternatively, a film-forming element made of a tetrafunctional hydrolyzable silane derivative represented by a halogen atom) can be suitably used.

Here, the coating film forming element comprising the above-mentioned tetrafunctional hydrolyzable silane derivative includes tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane,
Tetrabutoxysilane, diethoxydimethoxysilane and the like can be suitably used.

The film-forming element composed of the silicate can be prepared by partial hydrolysis, dehydration-condensation polymerization or the like of the tetrafunctional hydrolyzable silane derivative.

As the method for applying the above coating composition, methods such as spray coating, dip coating, flow coating, spin coating, roll coating, brush coating, and sponge 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.

[0029]

【Example】

Reference example. Anatase type titanium oxide sol (Nissan Chemical, TA
-15, nitric acid peptizer, pH = 1), silica sol (Nippon Synthetic Rubber, Glasca A solution, pH = 4), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution) and ethanol, The coating liquid obtained by stirring for about 3 minutes is applied to a 10 cm square soda lime glass substrate by a spray coating method, and heat-treated at 200 ° C. for 15 minutes to obtain 11 parts by weight of anatase type titanium oxide particles and silica 6 A # 1 sample having a surface layer composed of 5 parts by weight of silicone and 5 parts by weight of silicone was obtained. The contact angle of the # 1 sample with water was 85 °. Here, the contact angle with water was evaluated using a contact angle measuring device (Kyowa Interface Science, CA-X150) by the contact angle with water 30 seconds after a water droplet was dropped from the micro syringe.
Next, 0.3 mW was applied to the surface of the # 1 sample using an ultraviolet light source (Sankyo Electric, black light blue (BLB) fluorescent lamp).
Irradiation was carried out for one day at an ultraviolet illuminance of / cm ² to obtain a # 2 sample.
As a result, the contact angle with water of the # 2 sample was hydrophilized to 0 °. Next, a mercury lamp was used for the sample # 1 and the sample # 2 for 22.8.
The surface of each of the # 3 samples obtained by irradiating with an ultraviolet illuminance of mW / cm ² for 2 hours was subjected to Raman spectroscopic analysis. as a result,#
The peak of the methyl group observed on the surface of one sample was not observed in the # 3 sample, but a broad peak of the hydroxyl group was observed instead. From the above, the organic group bonded to the silicon atom in the silicone molecule on the surface of the coating in response to the photoexcitation of the photocatalytic anatase-type titanium oxide is replaced with a hydroxyl group by photocatalysis, and is hydrophilized. I understand.

Embodiment 1 Anatase type titanium oxide sol (Nissan Chemical, TA-15) and silica sol (Nippon Synthetic Rubber,
(Glaska A solution), methyltrimethoxysilane (Nippon Synthetic Rubber, Glasca B solution), polytetrafluoroethylene (PTFE) particles (Daikin Industries, Lubron L-5) and ethanol are mixed and stirred for 2-3 hours. The obtained coating liquid is applied on a 10 cm square soda lime glass plate by a spray coating method, and is heat-treated at 200 ° C. for 15 minutes to obtain 33 parts by weight of anatase type titanium oxide particles, 66 parts by weight of polytetrafluoroethylene particles, # 4 having a surface layer composed of 6 parts by weight of silica and 5 parts by weight of silicone
A sample was obtained. The contact angle of the # 4 sample with water was 110 °. Next, the surface of the sample # 4 was coated with an ultraviolet light source (Sankyo Electric Co., Ltd., black light blue (BLB) fluorescent lamp) by 0.3%.
Irradiation was performed for one day at an ultraviolet irradiance of mW / cm ² to obtain a # 5 sample. As a result, the contact angle of the # 5 sample with water was 97.2 °, and did not change much. According to the above reference example, the portion where the silicone is exposed to the outside air is supposed to be replaced by a hydroxyl group by a photocatalytic action and the organic group bonded to the silicon atom in the silicone molecule to be hydrophilized. It is considered that the contact angle with the film slightly decreased. In other words, the surface of the # 5 sample has both a hydrophilic portion where the hydroxyl group is substituted by the photocatalytic action and the hydrophilicized silicone is exposed to the outside air and a water-repellent portion where the water-repellent fluororesin is exposed to the outside air. It is assumed that the structure is microscopically dispersed on the surface. The contact angle with water is 97.
When the angle was 2 ° and 90 ° or more, when the glass was tilted, the water drops rolled and fell.

Next, the # 5 sample and a soda lime glass plate for comparison were placed outdoors, and the cleanliness of the surface against deposits and contaminants was examined. The cleanliness of the surface against sediments and contaminants was determined by placing a sample as shown in FIG. 3 under a covered part on the roof of a building and exposing it for four months. As a result, some stains were observed on the soda lime glass plate, whereas no stain was observed on the # 5 sample.

[0032]

According to the present invention, at least the outer surface of the vehicle window glass is less likely to adhere to water droplets and dirt, thereby improving the safe driving performance of the vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram showing a surface structure of a vehicle window glass according to the present invention.

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

FIG. 3 is a diagram showing a method of setting a test sample according to the embodiment of the present invention.

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Claims (2)

[Claims] 1. A substantially transparent surface layer containing photocatalytic oxide particles, silicone and a water-repellent fluororesin is formed on at least the outer surface of a window glass substrate, and the surface of the layer is made of water. A vehicle window glass having an antifouling property and a property of preventing water droplets from adhering, characterized by having a contact angle of 90 ° or more. 2. A substantially transparent surface layer containing photocatalytic oxide particles, amorphous silica, and a water-repellent fluororesin is formed on at least the outer surface of the window glass substrate, and the surface of the layer is formed. Is a vehicle window glass having both an antifouling property and a waterdrop adhesion preventing property, wherein a contact angle with water is 90 ° or more.