JPH07315882A - Water-repelling reduced-reflection glass - Google Patents

Abstract

PURPOSE:To produce a water-repelling reduced-reflection glass having water and oil repellency and stain proofing properties without reducing optical- properties, reduced in reflection, designed so as to exhibit the properties more effectively, excellent in adhesion, scuff resistance, weather resistance, etc., maintaining these properties over a long period, capable of satisfactorily dealing with adhesion of water or stains according to the simple wiping method and useful as, especially an automobile window glass. CONSTITUTION:This is a reduced-reflection glass reduced in reflection on the glass surface by putting an oxide thin film having a different refractive index on one side of a glass base in layers. In this reduced-reflection glass, an SiO2 thin film containing polyfluoroalkyl group-containing silane compounds bonded to the surface and having <=1.50 refractive index (n) or a thin film of a mixture oxide composed of SiO2 and another oxide is formed on the side opposite to the side on which the thin film is put in layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces reflection on one side of a glass substrate used for vehicles, construction or general industry, and particularly for vehicles, the dashboard during driving or the peripheral portion thereof is specified. It has the effect of reducing the glare phenomenon on the windshield attached at an inclination angle, and at the same time has water repellency on the opposite surface (reflection surface), especially on the vehicle exterior surface, especially when water or dirt is on the surface. The film has at least the effect of making it difficult to adhere to the film, and the film is made to have a reflection reducing performance or / and to strengthen the reflection reduction as a whole, and the transmission in the viewing direction is performed without impairing the optical characteristics. The present invention provides a useful water-repellent reflection-reducing glass which increases the property and contributes to the improvement of safety especially in a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, an oxide film having a different refractive index is laminated on a glass substrate, and the multiple interference is used to reduce the reflectance of the glass substrate to improve the transparency.
The so-called multilayer low-reflection glass is known among those that are more safe, have excellent habitability, and are environmentally friendly not only for drivers and passengers in the vehicle but also for oncoming vehicles. It has been widely used for construction, industry, vehicles, etc.

Particularly, for example, in the conventional low reflection performance used for a windshield mounted at a specific inclination angle in an automobile window, the purpose is to reduce the reflected light from the front side, and the vertical direction of the windshield surface. The low reflection effect is halved for obliquely incident light having an incident angle with a line (hereinafter referred to as a normal) of 50 ° to 70 ° or more. The visibility of the foreground at the time of driving is reduced due to the surrounding objects being reflected on the windshield, which causes a reduction in safety and the like.

On the other hand, for example, Japanese Patent Laid-Open No. 17601/1993 describes a method for forming an antireflection coating. Further, as a laminate of two antireflection films, for example, Japanese Patent Laid-Open No. 64-70701. The publication describes a transparent plate having a conductive antireflection film, and as a laminate of three layers of antireflection film, for example, JP-A-61-189501 discloses a transparent low reflection plate. It is known that

However, in these multilayer low reflection glass, the refractive index and the film thickness are strictly calculated in order to express the desired optical characteristics, and if the predetermined film constitution is not achieved, the target optical characteristics are When stains such as hand stains, oil and water stains adhere to the low reflection film, they will act as a new thin film formed on the low reflection film. Will occur.

In this case, the optical design of the dirty portion is broken, the reflectance is higher than that of the surrounding normal low reflection portion, and it becomes very conspicuous, impairing the transparency and aesthetics. It was a thing.

In particular, when oily stains such as fingerprints are attached, unless they are completely wiped off with a solvent such as alcohol to completely remove the stains, it is likely that the appearance will be impaired forever and it is difficult to say that it is environmentally friendly. This causes various problems such as wiping traces remaining easily.

Among the above, for example, Japanese Examined Patent Publication No. 3-23493 discloses a low reflectance glass having antifouling property and has a refractive index of 1.60 or more composed of a condensate containing a metal oxide on the surface of the glass. It is disclosed that a two-layer film is formed on the thin film and a thin film made of a condensate of a fluorine-containing silicone compound having a polyfluorocarbon chain having two or more carbon atoms to which fluorine atoms are bonded. However, in order to obtain water repellency and low reflectivity at the same time, a solution obtained by mixing F-alkylsilane and Si-alkoxide to form a hybrid is used.

[0009]

As described above, for example, in Japanese Patent Application Laid-Open No. 3-17601, a coating having a concentration gradient of light metal fluoride with respect to the thickness of the coating is formed by using a sol-gel technique. It is difficult to say that the method for forming is economically efficient, highly productive and economical. Further, for example, in the ones disclosed in JP-A-64-70701 and JP-A-61-189501, sufficient and stable desired reflection reduction can be obtained with respect to the above-mentioned specific oblique incident light. Further, it is difficult to say that both of them have durability required for a vehicle. Further, for example, the one disclosed in Japanese Examined Patent Publication No. 3-23493 discloses that the final heating temperature of the film is 400 ° C. or lower, for example, 160 to 200 ° C. in order to prevent the decomposition of F-alkylsilane. There is a problem that only low strength products can be obtained.

Further, the effect of reducing reflection, which is exhibited when two to three oxide thin film layers are formed on only one surface of the glass substrate, is in the range of 4 to 6%, which is still much higher than that of untreated glass. However, it is desirable that a higher reflection reduction effect can be exhibited if possible.
However, for this reason, even if a thin film layer is laminated on the same surface, almost no improvement in performance can be expected.
Even if the following slight improvement is observed, the durability of the film becomes insufficient as the number of laminated thin film layers increases, or the homogeneity of the thin film layer decreases and the commercial property tends to decrease. In addition, the manufacturing process is complicated and the cost is increased.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is realized when two to three oxide thin film layers are formed on only one surface of a glass substrate. In order to enhance the reflection reducing effect without increasing the number of laminated thin film layers on the same surface side, the surface opposite to the surface on which the thin film layer is formed is most suitable for normal vehicles, construction or industrial use. By forming a thin film having a refractive index of 1.50 or less, which is lower than the refractive index n = 1.51 to 1.53 of commonly used soda lime silicate glass, the light is transmitted through the two or three oxide thin film layers and is incident on the glass. Reflection on the opposite surface of light (also referred to as back reflection) is reduced, and performance is further improved by about 0.5 to 2.0% as compared with the case of only a few oxide thin film layers. Then, further, by introducing a polyfluoroalkyl group having a fluorine atom into the thin film, it is made to have an effect of preventing the adhesion of moisture and dirt, thereby enhancing the reflection reduction effect and the water repellency and dirt prevention effect. It is intended to provide a multi-functional water-repellent reflection-reducing glass having both of the following.

That is, the present invention is a reflection-reducing glass in which an oxide thin film having a different refractive index is laminated on one surface of a glass substrate to reduce reflection on the glass surface. It is characterized by forming a SiO ₂ thin film or a mixed oxide thin film of SiO ₂ and another oxide in which a silane compound having a ratio n of 1.50 or less and containing a polyfluoroalkyl group is bonded to at least the surface thereof. Water-repellent reflection-reducing glass.

The water-repellent reflection-reducing glass described above, wherein the SiO ₂ thin film or the mixed oxide thin film of SiO ₂ and another oxide has a refractive index n of 1.47 or less. In addition, the water-repellent reflection-reducing glass described above, wherein the silane compound containing a polyfluoroalkyl group is a monolayer or tens of minutes layer.

Further, the water-repellent reflection-reducing glass is a laminated glass in which at least two glass substrates are bonded to each other with an intermediate film or an intermediate film-like substance having a simple or various functionality interposed therebetween. Made of water-repellent anti-reflection glass.

Furthermore, in the water-repellent reflection-reducing glass, the laminated oxide thin film layer is formed of a thin film layer which has the lowest reflectance for incident light of a specific incident angle. Made of water-repellent anti-reflection glass.

Furthermore, in the water-repellent reflection-reducing glass, the specific incident angle is 40 to 80 °, and the reduction rate of the reflectance is 4.5 to 7% in visible light reflectance. The water-repellent reflection-reducing glass described above.

Furthermore, in the water-repellent reflection-reducing glass, a SiO ₂ thin film or Si having at least its surface coated with a silane compound containing a polyfluoroalkyl group is used.
A mixed oxide thin film of O ₂ and another oxide has a refractive index n of 1.43.
The water-repellent reflection-reducing glass as described above, which has a thickness of ˜1.47 and a thickness of 105-130 nm.

The water-repellent reflection-reducing glass is a front window for automobiles made of laminated glass, the oxide thin film layer for reducing reflection is the inner surface of the vehicle, and the silane compound containing a polyfluoroalkyl group is at least the same. The water-repellent reflection-reducing glass as described above, characterized in that the SiO ₂ thin film coated on the surface or a mixed oxide thin film of SiO ₂ and another oxide is the outer surface of the vehicle.

Furthermore, each of the oxide thin film layers of the reflection-reducing glass is formed by a sol-gel method using a solution containing at least one organic metal compound as a starting material. Reflection reduction glass.

Furthermore, a SiO ₂ thin film or a mixed oxide thin film of SiO ₂ and another oxide, at least the surface of which is coated with the silane compound containing a polyfluoroalkyl group, is once formed on the surface of the glass substrate as an SiO ₂ thin film. Alternatively, a mixed oxide thin film of SiO ₂ and another oxide is formed at a treatment temperature of 400 ° C or higher, and then a silane compound containing a polyfluoroalkyl group is applied to the surface of the oxide thin film or after application.
The water-repellent reflection-reducing glass described above, which is formed by drying at a temperature of 400 ° C. or lower.

Furthermore, the oxide mixed with SiO ₂ is TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ , SnO ₂ , In ₂ O ₃ , Ta ₂ O ₃
The water-repellent reflection-reducing glass as described above, which is any one of the above or a mixture thereof.

The water-repellent reflection-reducing glass described above, characterized in that the oxide thin film layer formed on one surface of the glass substrate is 2 or 3 layers. Furthermore, the uppermost layer of the oxide thin film layer is the same film as a SiO ₂ thin film formed on the opposite surface of the oxide thin film layer or a mixed oxide thin film of SiO ₂ and another oxide. And the water-repellent reflection-reducing glass described above.

Here, as described above, SiO ₂ or Si
As the mixed oxide of O ₂ and other oxides, it is preferable to have a structure having fine irregularities or pores on the surface layer, and a sufficiently strong minute surface with a unique shape and size. The surface area of the film is increased by forming irregularities or pores, and the polyfluoro group-containing silane compound that exhibits water repellency, oil repellency, and anti-staining property is simply bonded to the surface in a single to tens of minutes layer. Instead of binding to minute irregularities or inside pores, the adhesion amount of fluoride is increased to enhance its function, and also against the abrasion of the surface such as wiping, the polyfluoro group-containing silane compound The above properties can be left for a sufficiently long time so that their characteristics are not impaired.

The unevenness and pores formed on the surface layer are
The size is less than the wavelength of light in the visible range, and does not impair the transparency itself. Furthermore, the polyfluoroalkyl group-containing silane compound applied on this is colorless and transparent, and the polarizability of fluorine atoms is small. Therefore, the refractive index is as low as about 1.33 to 1.35, it is a low-refractive-index oxide film or less, and it is a single to tens of minutes layer, and is extremely thin.Thus, these treatments do not impair the transparency of the water-repellent reflection-reducing glass. There is no such thing.

Further, the other oxide to be mixed with SiO ₂ is TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ , SnO ₂ , In ₂ O ₃ or Ta ₂ O _3, etc. TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ , SnO ₂
It can be freely selected from various oxides, etc., and the SiO ₂ -based oxide thin film as the uppermost layer is preferably formed by a sol-gel method using a metal alkoxide as a starting material. After being mixed with the sol solution of ₂ system and being soluble, it becomes a homogeneous mixed oxide sol solution, and when the thin film of the mixed oxide is formed, the refractive index of the film does not exceed 1.50, preferably the refractive index. It is necessary to select a mixed oxide having a value of 1.47 or less.

Furthermore, as the silane compound containing a polyfluoroalkyl group, CF ₃ (CH ₂ ) ₂ Si (OC
_{H 3) 3, CF 3 (} CF 2) 5 (CH 2) 2 Si (OCH 3) 3, CF 3 (CF 2) 7 (CH 2) 2 Si
(OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCH ₃ (OCH ₃ ) ₂ , CF ₃ (CF ₂ ) ₃ (C
_{H 2) 2 Si (OCH 3} ) 3, CF 3 (CF 2) 7 (CH 2) a silane compound the carbon number such as ₂ SiCl ₃ includes a perfluoroalkyl group having from 1 to 20, or these hydrolysis The condensate can be used.

Further, as a method for forming the oxide thin film having the surface layer shape, for example, the method described in Japanese Patent Application No. 3-316992 filed by the applicant of the present application is the most suitable. Are different in average molecular weight as raw material solutions of oxides formed on the substrate, for example, several thousand and several hundred thousand,
By using a solution prepared by mixing two kinds of precursor sols and controlling the mixing ratio thereof, an arbitrary surface layer shape, for example, irregularities or pores can be specifically expressed.

Further, as a method for applying the silane compound containing a polyfluoroalkyl group onto the oxide thin film having the surface layer shape having the irregularities or pores, for example, the present applicant first Japanese Patent Application No. 4 filed
The coating method described in No. 16688, which is a low-reflection glass formed by laminating oxide thin films based on strict optical design, and originally has durability with low visible light reflection performance. The unique surface layer provided with water repellency
It imparts oil repellency and stain resistance, and synergistically and comprehensively becomes one and sufficiently exerts its performance even for a long period of time.

That is, the low refractive index film of the oxide thin film which is the uppermost layer on the air side is a SiO ₂ -based oxide thin film (refractive index n = 1.43) which gives the lowest refractive index among various oxide thin films. ~
1.47) makes it possible to form the film thickness to a predetermined thickness based on the optical design while ensuring the low refractive index and the surface layer shape controllability capable of obtaining the unique irregularities and pore shapes. As a result, predetermined optical characteristics are also expressed at the same time, which makes it possible to dramatically prevent deterioration of the low reflection effect due to adhesion of dirt, which was a fatal defect of low reflection glass in the past. .

Furthermore, the glass substrate is an inorganic (in some cases, organic) transparent plate glass, which is colorless or colored, and its type or color tone,
The shape and the like are not particularly limited, and further, as bent plate glass, of course, various coated glass, various tempered glass and strength-up glass, can be used in flat plates and single plates, and can also be used as double glazing or laminated glass. Needless to say. In particular, it exhibits its function remarkably in laminated glass used for a windshield for automobiles.

[0031]

As described above, the water-repellent reflection-reducing glass of the present invention has a reflection-reducing layer formed by laminating oxides having different refractive indexes on one surface of a glass substrate, and the opposite surface of the reflection-reducing layer surface. Alternatively, on the opposite surface and the uppermost layer of the reflection reduction layer, for example, SiO having a specific depth with minute irregularities or pores with a specific diameter and having a specific refractive index and a specific fluoride. ₂ or by forming at least a mixed oxide of SiO ₂ and another oxide thin film,
Adhesiveness can be improved and it can be made a stubborn thin film, and the adhesion is significantly improved not only at the interface with the glass substrate but also at the film-to-film interface in the laminated film, and the effect of reducing reflection while maintaining water repellency. To have sufficient transparency and excellent wear resistance and durability, and to be transparent and have high hardness, and at the same time to exhibit predetermined optical properties and the like, which can be sufficiently satisfied. In addition to imparting a reflection reducing effect, it also imparts water repellency, oil repellency, and anti-staining properties to deteriorate the transparency due to the adhesion of stains peculiar to the reflection reducing glass, the deterioration of the low reflection effect and the aesthetic deterioration. Can be drastically controlled and prevented, water and dirt that impair the optical characteristics are hard to adhere, and even if they adhere, they can be removed very easily by wiping.
Furthermore, the surface wear due to wiping and the like is also reduced, and the deterioration of these characteristics is drastically reduced, and the excellent characteristics can be maintained for a longer period of time, and it is highly safe and does not require a troublesome process and is inexpensive. As a result, the water-repellent reflection-reducing glass can be effectively obtained, which is widely useful not only for building window materials but also for vehicle window materials.

[0032]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the embodiment.

Example 1 An alkoxide of Ti and an alkoxide of Si were mixed so as to have an oxide-equivalent molar ratio of about 43:57, and a solvent such as isopropyl alcohol was added to the mixture to give a solute concentration of about 0.45 mol /
adjusted to l. The viscosity of the alkoxide solution is about 2 mPa ·
It was s (cps).

Next, the size is the size of an automobile windshield, and a float glass substrate (bronze color) having a thickness of about 2 mm is sequentially washed with a neutral detergent, water rinse, alcohol, acetone, etc., and dried. , Masking one surface of the glass substrate with a masking tape, immersing the glass substrate in the preparation solution, gently pulling upward at a constant speed of about 3.0 mm / sec, to form a gel film on the glass substrate,
The masking tape was removed and placed in an electric furnace maintained at about 280 ° C. for about 10 minutes and dried and heated to obtain a first layer of SiO ₂ TiO ₂ based oxide thin film.

Next, a masking tape was attached again to the non-film-forming surface of the above glass substrate, the solute concentration was adjusted to about 0.25 mol / l, and the glass substrate was immersed in a Si alkoxide solution having a viscosity of about 6 mPa · s. , Gently pulling upward at a constant speed of about 4 mm / sec, remove the masking tape as in the first layer, hold again at about 280 ° C for about 10 minutes, dry and heat,
A SiO ₂ oxide thin film as a layer was obtained.

Then, tetraethoxysilane [Si
(OC ₂ H ₅ ) ₄ ] as a starting material, and hydrolyzed and polycondensed of this as a silica sol (a) having a weight average molecular weight of about 126,000,
Monomethyltriethoxysilane [CH ₃ Si (C ₂ H ₅ ) ₃ ] was used as the starting material, and was hydrolyzed and polycondensed to obtain a silica sol (b) having a weight average molecular weight of about 3,200, which was converted to an oxide-based molar ratio. Solute concentration of about 0.4 mol
A homogeneous silica sol solution of 1 / l was prepared. The viscosity of this solution was about 2.5 mPa · s.

Into this solution, a new glass substrate (clear) having a size of 2 mm and one side of which was masked with a masking tape in the same manner as described above was dipped, and about 1
Gently pull up at a constant speed of 4.5 mm / sec, remove the masking tape, put it in the same electric drying oven as above, and weigh about 280
It was heated and dried at ℃ for about 10 minutes to obtain a SiO ₂ oxide thin film on one surface.

The two glass substrates thus obtained are supplied to a windshield production line for automobiles, and each of them is cut into a prescribed shape having the same shape, and then the film-forming surfaces of the two glass substrates face outward. As described above, bending and heating were performed so that the film forming surface of the bronze-colored glass substrate was concave and the film forming surface of the clear glass substrate was convex.

From a plurality of the obtained bent glass substrates for laminated glass, a pair was taken out and cut into small pieces, and the optical characteristics of each thin film layer were measured. The laminated thin film layer formed on the bronze glass substrate was Refractive index n ₁ = about 1.75, film thickness
d ₁ = SiO ₂ · TiO ₂ oxide about 100nm film, the second thin film layer refractive index n ₂ = 1.45, the thickness d ₂ = was SiO ₂ oxide film of about 118 nm. The thin film layer formed on the clear glass substrate had a refractive index n ₁ '= about 1.45 and a film thickness d ₁ ' = about 120 nm.

Next, the remaining bent glass substrates for laminated glass are once again separated separately, and the silane compound containing a polyfluoroalkyl group is hydrolyzed only on the SiO ₂ oxide thin film layer side of the clear glass substrate. Solution with a spoid
10 cc was dropped and spread evenly with a flannel cloth, and then this clear glass substrate was placed in the dry electric furnace and dried and heated at about 250 ° C. for about 30 minutes. A layer between the monomolecular layer and the tens of minutes was formed.

Further, again, the clear glass substrate and the bronze glass substrate of the other side which has been previously separated are placed between the two glass substrates in a polyvinyl butyral film (PVB).
After sandwiching (intermediate film) and performing pairing, the film was placed in an autoclave and heated under pressure to obtain a laminated glass for a front window.

The visible light reflectance of the thus obtained laminated glass on the concave surface side (the inner surface side of the vehicle when mounted as an automobile window) was measured with a spectrophotometer. The reflectance was about 9.3%. On the other hand, the combination of glass substrates without any thin film layer as described above is the same as the above, and the PVB interlayer film has the same thickness. The visible light reflectance was measured to be about 15.4%. Therefore, the laminated glass, which is the water-repellent reflection-reducing glass of the present invention, has a visible light reflectance reduced by about 6.1%.

The contact angle of water in the atmosphere on the convex surface of the laminated glass on the side of the clear glass substrate (the surface which becomes the outside of the vehicle when it is installed as an automobile window) is made by Kyowa Interface Science.
When measured with a CA-A type, it was about 110 to 115 ° and showed high water repellency. Further, even when stains such as oils and fats were attached, the glass was an excellent water-repellent reflection-reducing glass that was expected to be able to be wiped very easily with alcohol or the like, leaving no trace of alcohol wiping.

Furthermore, the water / oil repellency is less likely to deteriorate over a long period of time, and for example, a weather resistance test using an accelerated weather resistance tester (due panel weather meter) or an abrasion test using a # 40 broad cloth ( It was a good water-repellent reflection-reducing glass even in a traverse test, a reciprocal sliding test of about 1000 times under a load of about 100 g / cm ² ) and the like.

Example 2 A solution similar to that of the first thin film layer in Example 1 was prepared, and a glass substrate similar to that of Example 1 was used to form the solution at a pulling rate of about 3.2 mm / sec. As one thin film layer
A SiO ₂ TiO ₂ based oxide thin film was obtained.

Next, Ti alkoxide and Si alkoxide were mixed so that the molar ratio in terms of oxide was about 93: 7, and the mixture was mixed with a solvent such as isopropyl alcohol and a trace amount of about 0.3 wt%. Hydroxypropyl cellulose was added and mixed well to prepare a sol solution having a solute concentration of about 0.45 mol / l. The viscosity of the solution was about 7 mPa · s.

Then, the glass substrate on which the non-film-forming surface of the glass substrate on which the first thin film layer has been previously formed is masked again with a masking tape is dipped in the solution and gently pulled up at a constant speed of about 2.8 mm / sec. , Remove the masking tape,
By heating and drying for about 10 minutes in an electric furnace maintained at about 280 ° C., a SiO ₂ TiO ₂ based oxide thin film was obtained as a second thin film layer.

Further, on the second thin film layer, the second thin film of the first embodiment is formed.
The same operation as that for forming the thin film layer was performed to form the third thin film layer. However, the pulling rate at the time of forming the third thin film layer was about 3.8 mm / sec.

The same procedure as in Example 1 was carried out using the glass substrate having the three-layer laminated thin film layer thus obtained and the clear glass substrate having the water-repellent property obtained by the same operation as in Example 1. A laminated glass for a front window was manufactured.

Optical measurement of three thin film layers formed on the bronze glass substrate was performed by the same operation as in Example 1. As a result, the first thin film layer had a refractive index n ₁ = about 1.75 and a film thickness.
d ₁ = about 105 nm, second thin film layer has refractive index n ₂ = about 2.10, film thickness d ₂ =
About 135 nm, the third thin film layer has a refractive index n ₃ = about 1.45, film thickness d ₃ =
It was about 115 nm.

The visible light reflectance of the concave surface of the laminated glass thus obtained (the inner surface of the vehicle when mounted as an automobile window) was measured in the same manner as in Example 1. The incident light at an incident angle of about 65 ° was measured. The visible light reflectance was about 13.8%. On the other hand, the combination of glass substrates without any thin film layer as described above is the same as the above, and the PVB interlayer film has the same thickness. The visible light reflectance was measured to be about 19.9%. Therefore, the laminated glass, which is the water-repellent reflection-reducing glass of the present invention, has a visible light reflectance reduced by about 6.1%.

Further, the contact angle of water in the atmosphere on the convex surface of the laminated glass on the clear glass substrate side (the surface which becomes the outer side of the vehicle when mounted as an automobile window) was measured in the same manner as in Example 1, and it was about 110- It was about 115 ° and showed high water repellency. Further, even when stains such as oils and fats were attached, the glass was an excellent water-repellent reflection-reducing glass that was expected to be able to be wiped very easily with alcohol or the like, leaving no trace of alcohol wiping.

Further, as in Example 1, it was an excellent water-repellent reflection-reducing glass having high weather resistance and sliding resistance against water and oil repellency. Example 3 Zr alkoxide and Si alkoxide were mixed so that the molar ratio in terms of oxide was about 67:33, and then a mixed solvent containing isopropyl alcohol: ethyl cellosolve or the like was added and stirred to obtain a solute. An alkoxide solution having a concentration of about 0.3 mol / l was prepared. The viscosity of the solution was about 2.5 mPa · s.

Then, a glass substrate having a plate thickness of 8 mm, which was thoroughly washed, dried sufficiently, and covered with a masking tape on only one side, was immersed in the solution and gently pulled up at a constant rate of about 3.0 mm / sec to remove the masking tape. Removal, about
Heat and dry for about 15 minutes in an electric heating furnace kept at 350 ° C,
A SiO ₂ .ZrO ₂ based oxide thin film was obtained as the first thin film layer.

Next, the above glass substrate was immersed in the same solution used for film formation on the clear glass substrate in Example 1 without single-sided masking, and gently pulled up at a constant speed of about 4.5 mm / sec. The solution was applied to both surfaces and heated at about 350 ° C. for about 15 minutes to form a laminated thin film layer consisting of two layers on one surface and a single thin film layer on the opposite surface on a glass substrate.

Next, the obtained glass substrate was placed in a firing furnace, fired at about 550 ° C. for about 30 minutes and gradually cooled to obtain a flat glass substrate having thin film layers formed on both sides. Furthermore, only on the single-layer thin film layer side of the glass substrate thus obtained,
The water repellent solution used in Example 1 was applied, and the glass substrate was heated again at about 350 ° C. for about 20 minutes.

Optical measurement was performed on the obtained glass substrate in the same manner as in Example 1. As a result, the first thin film layer on the side where the two thin film layers were formed had a refractive index n ₁ = about 1.75 and a film thickness d ₁ = About 10
0 nm, second thin film layer has refractive index n ₂ = about 1.45, film thickness d ₂ = about 120 nm
And the single thin film layer on the opposite surface has a refractive index n ₁ '= about 1.45,
The film thickness d ₁ = about 120 nm.

Further, the visible light reflectance with respect to the incident light having an incident angle of 50 ° on the laminated thin film layer side of the two layers of the glass substrate is about 5.3.
%, Which was a water-repellent reflection-reducing glass in which the visible light reflectance at the same incident angle on a glass substrate having the same thickness without any thin film formed was 10.7%, and the reflectance was reduced by about 5.4%.

The side of the glass substrate on which the single thin film layer was formed showed high water repellency when the contact angle to water in the atmosphere was 110 to 115 °, which was the same as in Example 1, and was used for construction and show windows. It was a water-repellent reflection-reducing glass showing suitable properties as the above.

Comparative Example 1 In Example 1, a bronze-colored glass substrate having two laminated thin film layers was used, and a thin glass layer was not formed on a clear glass substrate as a laminated glass. Laminated glass was prepared by using one that does not undergo the water repellent operation of applying the silane compound containing a polyfluoroalkyl group as described above.

In the laminated glass, the visible light reflectance at an incident angle of 60 ° is about 11.4%, and the visible light reflectance at the incident angle of 60 ° of the ordinary laminated glass for a front window is about 15.4%.
%, The visible light reflectance was reduced by about 4.0%, but the visible light reflectance was about 2.1% compared with the visible light reflectance reduction ratio of 6.1% in the case of the laminated glass of the water repellent reflection-reducing glass of the present invention of Example 1. Was inferior in the effect of reducing the reflectance, and was insufficient.

Comparative Example 2 In Example 2, the bronze-colored glass substrate on which three laminated thin film layers were formed was used, and the thin glass layer was not formed on the clear glass substrate which is the counterpart of the laminated glass. Laminated glass was prepared by using one that does not undergo the water repellent operation of applying the silane compound containing a polyfluoroalkyl group as described above.

In the laminated glass, the visible light reflectance at an incident angle of 65 ° is about 16.0%, and the visible light reflectance at the incident angle of 65 ° of the ordinary laminated glass for a front window is about 19.9%.
%, The visible light reflectance was reduced by about 3.9%, but it was about 2.12% as compared with the visible light reflectance reduction rate of 6.1% in the case of the laminated glass of the water repellent reflection-reducing glass of the present invention of Example 1. Was inferior in the effect of reducing the reflectance, and was insufficient.

Comparative Example 3 In Example 3, the same two laminated thin film layers were formed on one surface of the glass substrate and the other surface was masked to form no thin film. The visible light reflectance at an angle of 50 ° was about 7.2%, which was lower than that of Example 3 by about 1.9%.

[0065]

As described above, according to the water-repellent reflection-reducing glass of the present invention, the reflection-reducing rate is about 6% or more at the mounting angle of the front window with a simple and easy film forming means. Reflection performance and contact angle 110-115
A film with water and oil repellency that is about ° and stain resistance can be obtained inexpensively and efficiently, and its performance is remarkably demonstrated.
It has excellent water and oil repellency, stain resistance, adhesion, scratch resistance, weather resistance, etc. without deteriorating optical properties, retains its performance for a long time, and can be easily wiped off even if moisture or dirt adheres. Since it can be sufficiently dealt with, it can be suitably used in various glass articles such as window materials for construction or automobiles.

Claims (13)

[Claims] 1. A reflection-reducing glass in which an oxide thin film having a different refractive index is laminated on one surface of a glass substrate to reduce reflection on the glass surface, and the refractive index n is 1.50 on the surface opposite to the surface on which the thin film is laminated. Si having a silane compound containing at least the following and containing a polyfluoroalkyl group bound to its surface
A water-repellent reflection-reducing glass, which is formed by forming an O ₂ thin film or a mixed oxide thin film of SiO ₂ and another oxide. 2. The water-repellent reflection-reducing glass according to claim 1, wherein the SiO ₂ thin film or the mixed oxide thin film of SiO ₂ and another oxide has a refractive index n of 1.47 or less. 3. The water-repellent reflection-reducing glass according to claim 1, wherein the silane compound containing a polyfluoroalkyl group is a monolayer or tens of minutes layer. 4. The water-repellent reflection-reducing glass is a laminated glass in which at least two glass substrates are adhered to each other with an intermediate film or an intermediate film-like substance having a simple or various functionality interposed therebetween. Item 3. A water-repellent reflection-reducing glass according to items 1 to 3. 5. The water-repellent reflection-reducing glass, wherein the stacked oxide thin film layers are thin film layers that have the lowest reflectance for incident light at a specific incident angle. The water-repellent reflection-reducing glass according to any one of 1 to 4. 6. The water-repellent reflection-reducing glass, wherein the specific incident angle is 40 to 80 °, and the reduction rate of the reflectance is 4.5 to 7% in visible light reflectance. The water-repellent reflection-reducing glass according to claim 1. 7. In the water-repellent reflection-reducing glass, a SiO ₂ thin film having a surface thereof coated with a silane compound containing a polyfluoroalkyl group or a mixed oxide thin film of SiO ₂ and another oxide has a refractive index n is 1.43 to 1.47,
7. The water repellent reflection-reducing glass according to claim 1, which has a film thickness of 105 to 130 nm. 8. The water-repellent reflection-reducing glass is a front window for automobiles made of laminated glass, the oxide thin film layer for reducing reflection is the inner surface of the vehicle, and at least a silane compound containing a polyfluoroalkyl group is used. The SiO ₂ thin film coated on the surface or a mixed oxide thin film of SiO ₂ and another oxide is the vehicle exterior surface.
The water-repellent reflection-reducing glass according to any one of 7 to 7. 9. The oxide thin film layer of the reflection-reducing glass is formed by a sol-gel method using a solution containing at least one organometallic compound as at least a starting material. The water-repellent reflection-reducing glass described. 10. A SiO ₂ thin film having at least its surface coated with a silane compound containing a polyfluoroalkyl group or a mixed oxide thin film of SiO ₂ and another oxide is once formed on the surface of a glass substrate as an SiO ₂ thin film or Form a mixed oxide thin film of SiO ₂ and other oxides at a processing temperature of 400 ° C or higher,
A silane compound containing a polyfluoroalkyl group is then applied to the surface of the oxide thin film, or after the application, the silane compound is dried at a temperature of 400 ° C. or less to form a film.
9. The water-repellent reflection-reducing glass as described in 9 above. 11. The oxide mixed with the SiO ₂ is TiO ₂ , Zr
4. Any one of O ₂ , Al ₂ O ₃ , B ₂ O ₃ , SnO ₂ , In ₂ O ₃ and Ta ₂ O ₃ or a mixture thereof.
10. The water-repellent reflection-reducing glass as described in 10 above. 12. The water-repellent reflection-reducing glass according to claim 1, wherein the oxide thin film layer formed on one surface of the glass substrate is 2 or 3 layers. 13. The uppermost layer of the oxide thin film layer is the same film as a SiO ₂ thin film or a mixed oxide thin film of SiO ₂ and another oxide formed on the opposite surface of the oxide thin film layer. The water-repellent reflection-reducing glass according to any one of claims 1 to 12.