JPH05330856A - Low-reflecting glass - Google Patents

Abstract

PURPOSE:To obtain such a low reflection glass that shows significant performance and excellent water-or oil-repellent property, contamination resistance, adhesive strength, scratching resistance and weather resistance, can maintain its performance for a long period and can be cleaned only by wiping the surface even water or dirt deposits, and thereby, is suitable for building material or automotive window or various glass products. CONSTITUTION:This low reflection glass has oxide thin films having different refractive indexes laminated on a glass substrate. The uppermost layer adjacent to air is SiO2 film or oxide mixture film of SiO2 with other oxides and has a rough surface with several 10 to several 100nm height or pores of several 10 to several 100nm diameter and has 1.40-1.60 refractive index and 70-130nm thickness. Further, the surface of the uppermost layer is coated with a silane compd. containing polyfluoroalkyl groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure in which water and dirt, which cause deterioration of optical characteristics, hardly adhere to the surface, and even if they adhere, they can be removed by extremely simple wiping. Of course, the present invention provides a useful low reflection glass that can be used for various glass articles for aircraft or vehicles, especially for automobiles.

[0002]

2. Description of the Related Art Conventionally, for example, a so-called multi-layer structure in which 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 and improve the transparency. Low-reflection film glass is known, and is actually widely used for construction, industry, vehicles and the like.

However, in these multi-layered low reflection glass, the refractive index and the film thickness are strictly calculated in order to express the desired optical characteristics, and the target optical characteristics are not obtained when the film composition is out of the predetermined film constitution. The same problem because stains such as hand stains, oil, and water stains adhere to the low reflection film, and these stains act as a new thin film formed on the low reflection film. Will occur.

In this case, the optical design of the soiled portion is broken, the reflectance is higher than that of the normal low-reflectance portion in the surroundings, and it becomes very conspicuous, which impairs the transparency and aesthetics. It was a thing.

In particular, when oily stains such as fingerprints are attached, unless they are wiped off completely with a solvent such as alcohol to completely remove the stains, it is easy to keep the aesthetic appearance 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 (Kokoku) No. 3-23493 describes a low reflectance glass having an antifouling property, and a refractive index of 1.60 or more formed 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, the final heating temperature of the film is 400 ° C in order to prevent the decomposition of F-alkylsilane by using a mixed solution of F-alkylsilane and Si-alkoxide. Below, for example, 160 to 20
Since the temperature is about 0 ° C., there is a problem that only the uppermost film having low hardness and strength can be obtained.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and as the low refractive index film on the air side, Si is used as the low refractive index film on the air side, as in the case of the low reflection glass itself.
A mixed oxide of O ₂ or SiO ₂ and other oxides is formed on the surface layer with minute irregularities of several tens to several hundreds nm or a diameter of several tens to several tens.
The structure has pores of 0 nm, and at least it is formed by controlling the film thickness so as to satisfy the antireflection condition, and then the surface layer including the irregularities or pores is coated with a polyfluoroalkyl group-containing silane compound. By
At the same time as imparting a low reflection effect, it is also possible to impart water repellency, oil repellency and anti-staining property to prevent deterioration of the transparency and aesthetics due to the adhesion of stains peculiar to the low reflection glass. It is intended to provide a low reflection glass capable of maintaining its excellent properties for a long period of time.

That is, according to the present invention, in a low reflection glass obtained by laminating oxide thin films having different refractive indexes on the surface of a glass substrate, the uppermost layer on the air side has minute irregularities or diameters of several 10 to several 100 nm on the surface. Is a mixed oxide of SiO ₂ or SiO ₂ and other oxides having pores of several tens to several hundreds nm, a refractive index of 1.40 to 1.60, and a film thickness of 70 to 130 nm. Further, a low reflection glass characterized in that the surface is coated with a silane compound containing a polyfluoroalkyl group.

Further, the low reflection glass is a laminated film formed on both surfaces of the glass substrate, and the visible light reflectance for incident light on the film surface side is reduced to 1% or less. The low reflection glass described above.

The low reflection glass is the laminated film formed on only one surface of the glass substrate,
The low reflection glass described above, which has a visible light reflectance of 3 to 5% with respect to incident light on the film surface side.

Further, the low reflection glass is a laminated film formed on only one surface of the glass substrate, and has a visible light reflectance of 4 to 40 for incident light of 40 to 80 ° on the film surface side.
The above-mentioned low reflection glass characterized by being reduced by 6%.

Further, the above-described low reflection glass, wherein the oxide film of the uppermost layer on the air side is formed by a sol-gel method using at least a metal alkoxide as a starting material. Furthermore, the oxide thin film of the uppermost layer on the air side is 400
The low reflection glass described above, characterized in that the treatment is carried out at a treatment temperature of ° C or higher, and then the surface of the oxide thin film is coated with a silane compound containing a polyfluoroalkyl group.

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
One of the above or a mixture thereof is provided.

Here, as described above, SiO ₂ or Si
The mixed oxide of O ₂ and other oxides has a structure that has minute irregularities or pores on the surface layer because it has a unique shape and size on the surface layer, Increase the surface area of the membrane by forming irregularities or pores,
A polyfluoro group-containing silane compound that exhibits water repellency, oil repellency, and anti-staining property is applied not only on the surface but also on minute irregularities or pores so that it accumulates sufficiently to increase the amount of adhesion on the surface layer. In addition to enhancing its function, the polyfluoro group-containing silane compound can be left for a sufficiently long time even when the surface is worn away such as wiping so that the characteristics thereof are not impaired.

The irregularities and pores formed on the surface layer are
The wavelength of light in the visible region is equal to or less than the wavelength of light, and does not impair the transparency itself, and the polyfluoroalkyl group-containing silane compound applied on this is colorless and transparent, and Since the atomic polarizability is small, the refractive index is low, and since it is the same as or lower than that of the low refractive index oxide film, these treatments do not impair the transparency of the low reflection glass.

Further, the other oxides mixed with SiO ₂ include various oxides such as TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ , SnO ₂ , In ₂ O ₃ or Ta ₂ O ₃ . are those that can be appropriately freely selected from among oxides, it is formed by a sol-gel method for the SiO ₂ based oxide thin film to be the uppermost layer as a starting material a metal alkoxide well, the SiO ₂ system It is possible to select an oxide that becomes a homogeneous mixed oxide sol solution after it is soluble and mixed with the sol solution, and that does not make the refractive index of the film 1.60 or more when a thin film of the mixed oxide is formed. is necessary.

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 ) ₂ SiCl ₃ , CF ₃ (CH ₂ ) ₂ SiCl
₃ , CF ₃ (CF ₂ ) ₃ (CH ₂ ) ₂ SiCl ₃ , CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ SiCl _{3 and} other silane compounds containing a perfluoroalkyl group having 1 to 20 carbon atoms Alternatively, a condensate obtained by hydrolyzing these 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 previously by the present applicant is the most suitable. Are different in average molecular weight as a raw material solution of oxides formed on a substrate, for example, several thousand and several hundred thousand,
By using a solution in which two kinds of precursor sols are mixed and controlling the mixing ratio thereof, an arbitrary surface layer shape, for example, irregularities or pores, can be specifically expressed.

Further, as a method of 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 methods described in No. 16688, which are made into low reflection glass by laminating oxide thin films based on strict optical design, and originally have 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), or merely by mixing trace amounts of other oxides to impart various physical properties in the SiO _2, by an oxide film of SiO ₂ system (refractive index n ≦ 1.60), specificity and the low refractive index While ensuring the surface layer shape controllability in which the irregularities and pore shapes are obtained, and at the same time to express the predetermined optical characteristics by forming the film thickness to a predetermined thickness based on the optical design, It is possible to dramatically prevent and control deterioration of the low reflection effect due to adhesion of dirt, which has been a fatal defect of low reflection glass.

Furthermore, the glass substrate is an inorganic or organic transparent plate glass, and is not particularly limited to colorless or colored and its kind, color tone, shape, etc., and further, as a bent plate glass, of course, It goes without saying that it can be used as various coated glass, various tempered glass, strength-up glass, flat plate or single plate, and also as multi-layer glass or laminated glass.

[0022]

As described above, the low reflection glass of the present invention is formed by laminating oxides having different refractive indexes on a glass substrate, and in the surface layer, fine irregularities with a specific depth or pores with a specific diameter are formed. Si having a unique and controlled refractive index and film thickness
This is because at least the uppermost layer is formed with a mixed oxide of O ₂ or SiO ₂ and another oxide thin film, and the specified compound is applied and coated on the uppermost layer to improve the adhesion. The film can be made a stubborn thin film, and the adhesiveness is significantly improved not only at the interface with the glass substrate but also at the film-to-film interface in the laminated film, with sufficient transparency and excellent abrasion resistance and durability. It is also transparent and has high hardness, and at the same time, it can be sufficiently satisfied by exhibiting predetermined optical characteristics and the like, and at the same time imparts a low reflection effect and at the same time has water repellency, oil repellency and anti-staining properties. Grant,
It is possible to dramatically control and prevent the deterioration of the transparency, the deterioration of the low reflection effect and the deterioration of the aesthetics due to the adhesion of stains peculiar to low reflection glass, and to prevent water and stains that impair the optical characteristics. It is difficult to adhere, and even if it adheres, it can be removed very easily by wiping, and further, surface abrasion during wiping etc. is reduced and damage to these characteristics is drastically reduced, and its excellent characteristics for a longer period of time. In addition to being maintainable, it can be obtained efficiently at low cost without the need for a highly safe and troublesome process. It will be.

[0023]

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 A float glass substrate having a size of about 300 mm × 300 mm and a thickness of about 3 mm was sequentially washed with a neutral detergent, water rinse, alcohol, acetone, etc. and dried, and then the glass substrate was treated with Si alkoxide. Approximate molar ratio of Ti alkoxide to oxide
Mix so that the ratio becomes 35:65, add a solvent such as isopropyl alcohol, and solute concentration is about 0.4 mol / l, and the viscosity is about 2 cps.
Dip it in an alkoxide solution adjusted to
Slowly pull it upwards at a constant rate of 4.3 mm / sec to form a gel film on the glass substrate, then put it in an electric furnace set at about 300 ° C for about 10 minutes and heat it to make the first layer of SiO ₂ · TiO _{2. 2}
A system oxide thin film was obtained.

Next, the alkoxide of Ti and a solvent containing ethanol as a main component are mixed to prepare a solute concentration of about 0.35 mol / l in an alkoxide solution adjusted to the above-mentioned SiO ₂ content.
・ Immerse the glass substrate with TiO ₂ -based oxide thin film to about 3.5 mm
It was slowly pulled up at a constant rate of / sec and heated at about 300 ° C. for about 10 minutes in the same manner as the first layer to obtain a second layer of TiO ₂ oxide thin film.

Next, tetraethoxysilane [Si
(OC ₂ H ₅ ) ₄ ] as a starting material, and hydrolyzed / polycondensed of the starting material to give 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) with 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
The above-mentioned glass substrate with the first and second layer oxide thin films was dipped in a uniform silica sol solution of 1 / l, and about 3.
It was slowly pulled up at a constant rate of 7 mm / sec and heated at about 300 ° C. for about 10 minutes in the same manner as the first layer to obtain a third layer of SiO ₂ oxide thin film.

Next, the above-mentioned three-layer thin-film laminated glass substrate was placed in a hot-air circulation furnace at about 550 ° C. in order to sufficiently sinter it into a high-density and complete oxide laminated thin film.
Heated for about 30 minutes.

In the obtained three-layer thin film laminated glass substrate with double-sided, the first layer of the laminated thin film has a refractive index n ₁ = about 1.90 and a film thickness d ₁
= About 75 nm, the second layer has a refractive index n ₂ = about 2.15, the film thickness d ₂ = about 64
nm, the third layer has a refractive index n ₃ = about 1.45 and a film thickness d ₃ = about 95 nm, and the visible light reflectance measured by a spectrophotometer is about 0.7% (about 8 to 8 9%) of low reflection glass, which was sufficiently excellent. Also, the uppermost third layer SiO ₂
When the surface layer of the oxide thin film was observed with an electron microscope, a large number of micropit-like pores with a diameter of about 40 to 70 nm were observed, and it became the desired surface layer.

Then, a trichlorofluoroalkylsilane [CF ₃ (CF ₂ ) ₇ (CH _2
2 ) ₂ SiCl ₃ : made by TOSHIBA Silicone] was dropped using a spoid, and spread evenly over the glass substrate with a flannel cloth, and then wiped off with a flannel cloth soaked with acetone to eliminate unevenness. Then, it was dried at about 130 ° C. for about 10 minutes.

The low reflection property developed before the treatment did not change even after the treatment, and when measured by an ellipsometer, the refractive index n _{3 of} the third layer of SiO ₂ oxide thin film was about 1 .
It was almost unchanged at 45.

The contact angle of the low reflection glass thus obtained with water in the atmosphere was measured by Kyowa Interface Science Co., Ltd.
The contact angle is about 112 ° when measured with CA-A type, and it shows high water repellency.Also, even when dirt such as oil and fat is attached, it can be wiped off very easily with alcohol. It was an excellent low-reflection glass with no trace of wiping.

Further, the water / oil repellency is less likely to deteriorate over a long period of time. For example, in a weather resistance test using an accelerated weather resistance tester (due panel weather meter),
The contact angle with water is about 91 ° even after about 2000 hours, and in the abrasion test (traverse test) with # 40 broad cloth, even after about 1000 reciprocating sliding tests under a load of about 100 g / cm ² against water, It was a low reflection glass with a contact angle of about 85 °.

The low-reflection glass in the case where one surface of a clean glass substrate is covered with a masking tape and the above-mentioned three-layer thin film laminated film is formed only on the other surface of the glass substrate is measured by the spectrophotometer described above. The measured visible light reflectance was about 4.5%, which was similarly excellent low reflection glass as compared with the visible light reflectance of the glass surface without the thin film and without the film.

Example 2 As in Example 1, various alkoxide solutions were used on a clean glass substrate. The first layer was a SiO ₂ TiO ₂ -based oxide thin film and the second layer was TiO ₂ . Oxide thin film, and the third top layer
The second layer is a SiO ₂・ ZrO ₂ -based oxide thin film,
A three-layer thin film laminated glass substrate with a double-sided film was obtained, which was a mixed oxide thin film having a molar ratio of SiO ₂ and ZrO ₂ of about 78:22. The SiO ₂ .ZrO ₂ -based oxide thin film of the third layer had the same molar ratio of the silica sol (a) and the silica sol (b) as in Example 1 in terms of oxides of about 1: 3.5. A solution prepared by diluting Zr metal alkoxide tetrabutoxyzirconium [Zr (OC ₄ H ₉ ) ₄ ] with ethanol was added to the mixed silica sol solution, and the resulting mixture was sufficiently stirred.

The above-mentioned three-layer thin film laminated glass substrate is approximately 59
Heat at 0 ° C. for about 30 minutes. As a result, in the three-layer thin film, the first layer has a refractive index n ₁ = about 1.91, the film thickness d ₁ = about 55 nm, the second layer has a refractive index n ₂ = about 2.20, the film thickness d ₂ = about 60 nm, The third layer has a refractive index n ₃
= About 1.55, film thickness d ₃ = about 80 nm, and was a low reflection glass with a visible light reflectance of about 0.7% measured by a spectrophotometer as in Example 1.

Furthermore, when the surface layer of the uppermost third SiO ₂ .ZrO ₂ type oxide thin film was observed with an electron microscope,
Similar to Example 1, a large number of micropit-shaped pores having a diameter of about several tens nm were recognized, and the surface layer was a desired layer.

Then, trimethylfluoroalkylsilane [CF ₃ (CF ₂ ) ₇ (CH
₂ ) ₂ Si (CH ₃ ) ₃ ] was applied in the same manner as in Example 1 to perform water and oil repellency treatment. When the contact angle of the low reflection glass with water was measured in the same manner as in Example 1, it was found to be about 110 °.
It was an excellent low-reflection glass with high weather resistance and sliding resistance against oil repellency.

Example 3 In the same manner as in Example 1, the first layer was a SiO ₂ TiO ₂ type oxide thin film, and the molar ratio of SiO ₂ to TiO _{2 in} terms of oxide was about.
52:48 mixed oxide thin film, the second layer is Ti
O ₂ oxide thin film, and the third uppermost layer of SiO ₂ oxide thin film are coated on one side of a clean glass substrate with a masking tape, and the other side is formed as a three-layer thin film laminated film. A film was formed.

Further, the three-layer thin film laminated glass substrate was heat-treated at about 620 ° C. for about 10 minutes in the same manner as in Example 1, and then,
Water and oil repellent treatment was applied. In the laminated thin film of the three-layer thin film laminated glass substrate formed only on one side, the first layer has a refractive index n ₁ =
About 1.85, film thickness d ₁ = about 90 nm, second layer has refractive index n ₂ = about 2.2
0, film thickness d ₂ = about 160 nm, the third layer has a refractive index n ₃ = about 1.45,
The film thickness d ₃ = about 120 nm, the visible light reflectance for oblique incident light with an incident angle of 60 ° on the film surface side is about 9.8%, which is about the same as when there is no untreated film. It was a 4.8% reduction.

Further, the low reflection glass exhibits high water and oil repellency as in the case of Example 1, so that dirt such as hand grime hardly adheres, and when adhered, alcohol can be used easily. It was an excellent low reflection glass that can be wiped off and has high weather resistance and sliding resistance with respect to the water and oil repellency.

Example 4 On one surface of a clean glass substrate, as a first layer, the molar ratio of SiO ₂ and TiO _{2 in} terms of oxide was about 45:55.
Mixing metal alkoxide of Si and Ti, solute concentration is about 0.5m
An alkoxide solution was prepared by diluting it with isopropyl alcohol so as to be ol / l, and using this solution, the same operation as in Example 1 was performed to form a SiO ₂ TiO ₂ based oxide thin film.

Furthermore, a SiO ₂ thin film was formed thereon by using the mixed silica sol used for the uppermost SiO ₂ thin film in Example 1. Further, the two-layer thin film laminated glass substrate was heat-treated at about 620 ° C. for about 10 minutes as in Example 3, and then subjected to the same water / oil repellency treatment as in Example 1.

In the laminated thin film of the two-layer thin film laminated glass substrate formed only on one side, the first layer has a refractive index n ₁ = about 1.87 and a film thickness.
d ₁ = about 78 nm, second layer has refractive index n ₂ = about 1.45, film thickness d ₂ = about
The obtained double-layer thin film laminated glass substrate has a visible light reflectance of about 9.9% for obliquely incident light with an incident angle of 65 °, and the reflectance is about 15.3% without a film. On the other hand, it was an excellent low-reflection glass that can reduce the reflectance for obliquely incident light rays by about 5.4%.

[0044]

As described above, according to the low reflection glass of the present invention, a film having low reflection performance, water repellency, oil repellency and stain resistance can be produced at low cost and with a simple and easy film forming means. A specific oxide thin film that is well obtained and has a stubbornly specified unevenness or pore-like surface layer having a unique shape in the film is obtained as the uppermost layer film, and the specific water-repellent oxide thin film is formed on the uppermost layer film. By applying the impregnated coating, it exerts its performance remarkably, does not impair the optical characteristics, is excellent in water and oil repellency, stain resistance, adhesion, scratch resistance, weather resistance, etc. Suitable for use in architectural or automotive window materials, various glass articles, especially automotive window materials, as it retains its performance and can be easily wiped off even if moisture or dirt adheres. it can.

Claims (7)

[Claims] 1. A low reflection glass comprising a glass substrate and a thin oxide film having a different refractive index laminated on the surface of the glass substrate. The uppermost layer on the air side has tens to hundreds of nanometers of minute unevenness or a diameter of tens to ten. It has pores with a diameter of several 100 nm and a refractive index of 1.40 to 1.
60, SiO ₂ or Si with film thickness controlled in the range of 70 to 130 nm
A low reflection glass, which is a mixed oxide of O ₂ and another oxide, and further has a surface of the uppermost layer coated with a silane compound containing a polyfluoroalkyl group. 2. The low reflection glass is the laminated film formed on both surfaces of the glass substrate, and reduces the visible light reflectance with respect to incident light on the film surface side to 1% or less. The low reflection glass according to claim 1. 3. The low-reflection glass is the laminated film formed on only one surface of the glass substrate, and the visible light reflectance for incident light on the film surface side is 3 to 5%. The low reflection glass according to claim 1, characterized in that: 4. The low reflection glass is the laminated film formed on only one surface of the glass substrate, and has a visible light reflectance of 4 to 40 with respect to incident light of 40 to 80 ° on the film surface side. 6
%. The low reflection glass according to claim 1, wherein the low reflection glass is reduced. 5. The low reflection glass according to claim 1, wherein the oxide thin film of the uppermost layer on the air side is formed by a sol-gel method using at least a metal alkoxide as a starting material. 6. The uppermost oxide thin film on the air side is 40
6. The low reflection glass according to claim 1, wherein the treatment is performed at a treatment temperature of 0 ° C. or higher, and then the surface of the oxide thin film is coated with a silane compound containing a polyfluoroalkyl group. 7. The oxide mixed with SiO ₂ is TiO ₂ , Zr
_2. 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.
The low reflection glass according to any one of 1 to 6.