FR2694551A1 - Hydrophobic glass pane, method of manufacture and corresponding glass article. - Google Patents

Abstract

A window glass capable of retaining good hydrophobic performance for a long period of time is provided. Window glass can be made by applying a mixture comprising a ceramic sol and a fluorine-containing compound to the surface of the glass, and forming a ceramic coating layer on the glass by heating. The sol of ceramic material is in particular a metal oxide in sol, the metal oxide in sol being in particular a zirconia sol dispersed in an organic solvent, which is obtained by replacing the water of the dispersed zirconia sol with the organic solvent. in water, by adding the organic solvent to the zirconia sol in water. The fluorine-containing compound is, in particular, a nonionic fluorinated surfactant or N- [3- (trimethoxysilyl) propyl] -N-n-propylperfluoroactyl sulfonamide.

Description

HYDROPHOBIC GLASS GLASS, METHOD FOR MANUFACTURING THE SAME

GLASS ARTICLE CORRESPONDING

  The present invention relates to a technique for forming a coating layer on a glass, such as a glass roof and a window glass for motor vehicles, a coating layer which provides said glass with a

hydrophobic property.

  A technique for coating a hydrophobic agent on a window glass is described in Japanese Patent Publication No. Hei 4-124,047. In this technique, the surface of the glass is first coated with a vehicle, which is obtained from the product of the hydrolysis and the polycondensation of a metal oxide in the presence of water, alcohol and a catalyst.

  coated glass is heated to form a coating layer

  The surface of the coating layer comprising the metal oxide is then treated with hydrofluoric acid or an etching attack.

  plasma, to form fine inequalities on its surface.

  Finally, the treated coated surface is coated with a hydrophobic agent based on fluorinated silicone, which contains a group

  polyfluoroalkyl (hereinafter referred to as Rf group).

  According to this treatment method for imparting the hydrophobic property, the elution of alkaline components from the glass component material can be prevented. However, this technique has the drawback of reducing the efficiency of the operation, since

  absolutely at least two methods of

  which is a first procedure for the application of

  coating the metal oxide on the glass surface, and a second procedure for coating a hydrophobic agent to impart the hydrophobic property over the oxide layer

  coated metal.

  Moreover, since the upper layer on the glass, where the fluorinated compound is coated, receives the greatest exposure to sunlight, the fluorinated compound present in the layer tends to absorb thermal energy from For this reason, the layer can not gain sufficient weather resistance and sufficient durability, which represents another disadvantage for this

technique of the prior art.

  A technique capable of solving the problem

  The above is described in Japanese Patent Publication No. Sho 58-122 979, in which the coating application of a mixture consisting of two different compounds on the surface of the glass is described. This technique comprises (1) the mixture of either an alkoxysilane compound, or a halogenated silane compound, with an Rf-containing silane compound, (2) attaching the resulting mixture to the glass, and (3) heating the mixture to enhance its bond with the surface with which it has been brought into contact, to thereby improve adhesion to glass and

  the hydrophobic property of the latter.

  In the prior art described above, a silicone-based composition comprising a silane compound is used as a component of the coating layer, however, since the hardness of the coating layer comprising the Silicone base is generally low, the layer has the disadvantage of easily undergoing abrasion, even by the repeated operations of windshield wipers on motor vehicles or the like. The present invention has been accomplished in view of the above problems, and relates to a hydrophobic window glass, comprising a glass substrate and a layer of ceramic material, formed on the surface of said substrate, wherein said substrate is the product heated with a mixture comprising a sol of ceramic material and a fluorine-containing compound, said sol of ceramic material being in particular a metal oxide in sol, such as a zirconia sol, and said fluorine-containing compound being in particular a compound

  non-ionic organofluorine, N-1 3- (trimethoxysilyl) propyl-

  N-n-propylperfluorooctyl sulfonamide or the like, which is present in a concentration of 0.2% to 5% by weight and capable of forming bonds with the metal present in the ceramic sol as a group of the compound

containing fluorine.

  The present invention also relates to a method for producing a hydrophobic window glass, which comprises coating a mixture comprising a ceramic sol and a fluorine-containing compound on a glass substrate, and heating said coated glass substrate, said mixture being in particular subjected to an aging step, said method comprising in particular immersing said glass substrate in said mixture and removing said substrate from said mixture at a speed lying in the range of 5 mm / min at 50 mm / min, and said heating step being in particular carried out at a temperature of 200 to 4000 C. According to the present invention, the

  coating is formed on the glass by coating application

  the soil mixture, prepared by mixing the ceramic soil having excellent adhesion to the glass and the fluorine-containing compound having a hydrophobic property, such that the fluorine-containing compound penetrates into the interior of the coating layer. As a result of the fact that the fluorine-containing compound remains in the coating layer even if the surface of the coating layer has been abraded, the hydrophobic and oleophobic properties are maintained under good conditions on a surface. In addition, the present invention can be effective in saving time and manpower, as well as improving the efficiency of the operation, because the process for coating the glass surface can be accomplished in one

only operation.

  Figures 1 to 4 illustrate the conforming examples

to the present invention.

  Figure 1 is a correlation graph between the concentration of the fluorine-containing compound and the tarnish index, to explain the relationship between the concentrations of the fluorine-containing compound and the tarnishing index, Figure 2 shows the correlations between the glass removal rate and hydrophobic performance, and between the glass removal rate and the transmission factor; Figure 3 shows the correlations between the heating temperature and the hydrophobic performance, and between the heating temperature and the water resistance; and FIG. 4 is a correlation graph between the protection ratio and the wavelength, which shows the percentage of protection of the zirconia vis-à-vis the

ultraviolet rays.

  In the present invention, the term "ceramic sol" is defined as a suspension of fine ceramic particles dispersed in a dispersion vehicle. The ceramic sol is capable of forming a coating layer of the ceramic material by Heating the ceramic floor covering A ceramic floor, which can form a coating layer which causes little decrease in the

  transparency of the glass, is preferable.

  For a concrete example of the ceramic sol, a zirconia sol (including a compound containing zirconia in soil), which is a metal oxide in soil, can be given as an example. zirconia, dispersed in an organic solvent which can be obtained by replacing with an organic solvent the water of the zirconia sol dispersed in water, by adding said organic solvent to the zirconia sol in water (see application by Japanese Patent No. Hei 3-218,928), is particularly preferable because a transparent, crystalline coating layer can be formed by use thereof in the mixture with the fluorine-containing compound. replacing the water of the zirconia sol dispersed in water, it is possible to indicate the ketones, the carboxylic acids, the esters, the polyhydric alcohols, the glycols and the solvents having hydrophilic groups, such as -COOH, -OH and the like , in the urs molecules, or mixtures of two organic solvents

previous ones, or more.

  In the present invention, the term "zirconia sol" is defined as a suspension in an organic solvent in which fine particles of

zirconia are dispersed.

  Zirconia, which is a component of zirconia soil,

  has excellent chemical stability, and is stable vis-

  For this reason, it hardly decomposes or melts, and it can decrease the dissolution of the coating layer, caused by the adhesion of acids or alkalis from the In addition, it has the function of inhibiting the elution of alkaline components from the inside of the material constituting the glass, thus giving the coating layer an improved weather resistance. furthermore, the zirconia sol coating layer can provide the additional advantages of providing sufficient protection of the ultraviolet rays as well as providing the layer with a higher hardness compared to the oxide coating layer.

non-metallic, such as silica.

  In the present invention, the term "glass" is defined as a glass for motor vehicles, as represented by natron limestone glass, etc. In the present invention, the term "fluorine-containing compound" is defined as a compound that contains fluorinated elements within it. Preferably, the compound

  containing fluorine is one that can demonstrate

  high hydrophobic mance when contained in the layer

  ceramic coating and which has a transmission

high sivity of the rays.

  Alternatively, in order to prolong the hydrophobic performance over a long period of time, it is preferred to use a compound which can form bonds by polycondensation reaction, etc. with the zirconia contained in the

floor of ceramic material.

  When using the zirconia sol dispersed in the organic solvent to form the coating layer, a nonionic organofluorinated surfactant or Nl 3- (trimethoxysilyl) propyl] -Nn-propylperfluorooctyl sulfonamide and the like can be cited in As examples of the fluorine-containing compound which undergoes a polycondensation reaction with the zirconia sol The reaction can be accomplished by aging a mixture of said sol and said fluorine-containing compound.

  resulting shows good hydrophobic performance.

  In this case, it is preferred to adjust the content ratio of the fluorine-containing compound in the soil mixture to a concentration in the range of 0.2% to 0.5% by weight. In the above range, the mixture in prepared soil can ensure to have both the hydrophobic property and the

  transmissivity in good conditions.

  To form the coating layer specified in the present invention, the mixture containing the ceramic sol and the fluorine-containing compound is

  applied to the glass surface and then heated.

  In the operating mode above, it is still

  preferable to form the coating layer described above.

  The mixing ratio, for both the ceramic sol and the fluorine-containing compound, can be selected from the range which does not cause a defect. an increase in the fluorine-containing compound content enhances the hydrophobicity, but may cause bleaching, etc. of the coating layer, loss of transparency, dispersion of the contact angle and / or separation of the coating layer. coating from the glass by

  following a non-uniform coating.

  Any method of application may be used without restriction, provided that the method can

  allow the soil mixture to be applied to the glass.

  However, a method for easily forming the layer in a uniform thickness is preferably employed. As a preferable example, an immersion method is employed for the formation of the coating layer in the sol-gel process. the thickness of the layer can be adjusted, either by varying the rate of shrinkage of the glass, or by repeating the immersion procedure, and the thickness of the

  layer should be determined within a range where

  etc., and a detachment of the layer can not occur As a rule, an increase in thickness

  of the coating layer will lead to such defects.

  The application of the mixture in soil can be carried out either

  two sides of the glass, on one side of the glass, in accordance

  In addition, a coating layer thickness capable of providing both the hydrophobic property and the transmissivity under good conditions can be obtained by varying the rate of shrinkage of the glass within the range from 5 mm / min at

mm / min.

  The heating conditions can be chosen within a temperature range in which the ceramic material can be stable and in consideration of the thermal resistance of the fluorine-containing compound, so

  to form the coating layer in good conditions.

  When the zirconia sol is used for the coating, it is preferable to set the heating temperature to be in the range of 200 to 4000 C. If the temperature is below this range, the abrasion resistance the coating layer tends to decrease, and, if the temperature is above 400 ° C, the hydrophobic performance tends to decrease as well. The heating time can be appropriately selected in connection with the heating temperature, and is not specifically limited In general, the duration is preferably within the range of about 3

at about 120 minutes.

  In view of the reaction time required for the polycondensation reaction between the zirconia sol and the fluorine-containing compound, it is preferable to age the mixture before coating. This aging is preferably carried out in a white chamber. at a temperature maintained within the range of 230 C to

  260 C and at a relative humidity of 45% to 55%.

  We will now explain the hydrophobic glass window manufacturing process, having a hydrophobic ceramic coating layer, using the sol-gel process, which can easily penetrate the

  fluorine-containing compound in the coating layer.

  Soil preparation according to the process

sol-gel is described first.

  For the ceramic floor, zirconia sol (Zr O 2) (manufactured by Nihon Shokubai Co, Ltd), prepared by grounding a zirconia, which is a transparent ceramic material, and an oxide metal, is used as an intermediate vehicle to improve the adhesion of various fluorine-containing compounds, exemplified below, to the glass surface. The fluorine-containing compound should be mixed in an amount capable of enabling it to exhibit sufficient hydrophobic performance. In other words, the contact angle, indicative of hydrophobicity, should be at least about 80 degrees. It is preferable to prepare the mixing ratio for the fluorine-containing compound so that it is more than about 0. , 2% by weight As regards the proportions of water and an organic solvent, they are preferably 50% and 47% by weight, respectively, when

  the proportion of zirconia in the soil is 3% by weight.

  However, as shown in the results of Figure 1, the fading index (diffusion transmittance / total transmittance) across the glass becomes high as the concentration of the fluorine-containing compound increases, thus causing defects such as bleaching etc. of the coating layer For this reason, it is necessary to choose the concentration of the fluorine-containing compound in the mixture at about 0.5% by weight, or below, so as to As a result, the concentration of the fluorine-containing compound is

  Preferably, in a concentration range of from about 0.2% to about 0.5% by weight, so as to retain both the hydrophobic property and the transmittance factor.

  Since the sufficient values of the hydrophobic property and the tarnish index can be obtained in the above range, it is possible to adjust the concentration of the fluorine-containing compound according to the locations for use and uses, depending on the importance of the hydrophobic performance,

the tarnishing index.

  In Figure 1, the darkening index (%) was measured using a phasemeter, comprising a light source unit having an incandescent lamp as a light source and a light receiving unit having a light source. integrated lamp, and is obtained according to the

following formula.

  Tarnish Rating = Diffusion Transmission Factor / Total Transmission Factor Total Transmission Factor = T 2 / T 1 x 100 Diffusion Transmission Factor = (T 4 -T 3 x T 2 / TI) / T 1 x 100 T 1: quantity of incident rays T 2: quantity of total rays transmitted through the test specimen T 3: quantity of rays scattered by the apparatus T 4: quantity of rays scattered by the apparatus and

the test sample.

  After mixing the zirconia sol with the fluorine-containing compound, it is best to age the mixture in soil.

  Molecules of the fluorine-containing compound lead indi-

  polycondensation reactions with the zirconia sol to form bonds with the zirconia as groups. This makes it difficult to diffuse the

  fluorine-containing compound from the coating layer

  even though the layer absorbs heat energy from sunlight, etc. The period of time for aging is preferably in a range from about 1 hour to about 50 hours. shorter than the above range, the adhesion of the coating layer to the glass is insufficient, so that the layer is easily detached from the glass On the contrary, if the period of time is longer than the range above, the coating layer tends to be uneven. fluorine-containing compounds used; (1) non-ionic organofluorinated surfactant; (2) Nl 3- (trimethoxysilyl) propyllN-n-propylperfluorooctyl sulfonamide The method of application for forming the coating layer according to the sol-gel process will now be explained since immersion is preferable as a method of application for the coating, the method

  previous is described on the basis of the immersion method.

  The washed glass is soaked in the soil mixture

  prepared in accordance with the operating mode described above.

  Then, the glass is removed vertically above the ground surface, at a speed of about 5 mm / min to about mm / min. If the speed is less than about 5 mm / min, the coating layer becomes thick as shown in FIG. 2, and the transmissivity of the light through the glass becomes insufficient. Furthermore, when the speed is greater than about 50 mm / min, the coating layer becomes thin, and the amount of the fluorine-containing compound contained In this case, the coating layer can not exhibit sufficient hydrophobic performance. Moreover, the resulting layer is uneven. As a result, it is necessary for the formation of the coating layer to choose the desired speed. removal of the glass within a range of about 5 mm / min to about 50 mm / min, so as to simultaneously impart both a good transmittance and a good hydrophobic property. Therefore, it is possible to determine the thickness of the coating layer appropriately for the particular fluorine-containing compound, by suitably adjusting the thickness of the coating layer.

  according to the locations for use and uses.

  In Figure 2, the hydrophobicity is determined by measuring the contact angle on the surface of the coating layer, after formation of the coating layer.

hydrophobic coating.

  In the present invention, the contact angle was measured by calibrating droplets of distilled water having a diameter of 1.5 mm, which was dropped onto the surface with an angle gauge of contact (produced by Kyowa Kaimen Kagakusha), at room temperature. The transmission factor was determined in the same way as that for the determination of the

  total transmission in Figure 1.

  After removal of the glass, the coated glass is heat-treated to enhance adhesion between the

  coating applied by immersion method and glass.

  The crystallization of the zirconia in the mixture proceeds as the heating temperature rises, increasing the adhesion between the coating layer and the glass, as well as the hardness of the coating layer, thereby improving In the present invention, it is preferable to set the temperature for heating in a range from about 200 ° C to about 400 ° C. The reason for this is that, if the heating is carried out at a temperature of about 2000 ° C, or below, the adhesion between the coating layer and the glass and the hardness of the coating layer will not be stabilized, whereas, if it is carried out at a temperature above about 4000 ° C, the groups of the fluorine-containing compound in the soil mixture, where a polycondensation reaction has been conducted during aging, can be released and then diffuse as a result of This provides a possibility of reducing both the initial hydrophobic performance and the water-resistance of the coating layer (see Figure 3). Nevertheless, it is possible to obtain a good initial hydrophobic performance and good resistance to water at a heating temperature of about 2000 C. However, the adhesion between the coating layer and the glass and the hardness of the coating layer both increase progressively as the temperature of the coating layer increases. heating is high beyond 2000 C, although the water resistance decreases in some cases, although

  the initial water-repellent property is not affected.

  Therefore, it is preferable to choose the temperature in a range close to 2000 C during a

  prescribed period as a condition for heating.

  In the above discussion, the determination of water durability was based on the results obtained by measuring the contact angle on the surface of the coated glass after soaking the glass in a bath maintained at 400 ° C. for 336 hours, then wash the glass by cleaning by

  ultrasound together with a detergent.

  We will now explain in more detail the formation of the coating layer according to the process

sol-gel.

  An example of the mixture in soil comprises 0.2% by weight of the fluorine-containing compound, 3% by weight of Zr O 2, 50% by weight of propylene glycol methyl ether, and 46.8% by weight of water. By allowing the mixture to age for approximately 24 hours, the optimum soil preparation can be obtained due to the course of a polycondensation reaction. The glass washed by polishing the surface to be coated with a detergent for the glass, such as oxide. of cerium or the like, is then placed in the soil-aged mixture By removing the glass in the vertical direction from the surface of the soil mix at a rate of 12 mm / min, a coating layer having a thickness of 0 , 04 pm, can be applied to the glass The coating layer, having the thickness above, gives a high value of the light transmittance of about 80% After the application of the mixture in soil on the glass , the coating layer is heated 2000 C for 2 hours, which provides a sufficient hydrophobic property, to provide a contact angle in the range of about 80 to about 110 degrees. The preceding condition gave similar results in the standard test on motor vehicle windshield (JIS R 3212, Provision 3 7), which results indicated

  excellent water resistance of the coating layer.

  As described above, the formation of the coating layer having excellent hydrophobic and oleophobic properties and excellent weatherability can be accomplished by the use of the sol-gel process described above. Since the coating layer according to the present invention is preferably based on zirconia, which is stable to acids and alkalis as a chemical property thereof, it is possible to prevent the remarkable decrease in the hydrophobic performance caused by the elution of components of the coating layer by acid rain In addition, zirconia has a hardness

  silane and silica which were traditionally

  As a result, the zirconia-containing coating layer has the advantage of providing less abrasion of the layer, which may be caused by repeated wiper movements and crack resistance caused by the sands. In addition, with regard to the transmissivity for ultraviolet rays, the zirconia sol can protect up to 60% of radiation even against rays having a 320 nm wavelength, whereas the glasses allow penetration ultraviolet rays with the wavelength of more than 300 nm, and silane and silica allow that of more than 200 nm In this respect, the transmission factor for ultraviolet rays, which is shown in Figure 4, means the percentage of protection of ultraviolet rays through zirconia soil placed in a cell that is

  measured using a spectrophotometer.

  The hydrophobic window glass, manufactured in the examples described above, is suitable for use in motor vehicle windows as described above; it goes without saying that it is applicable for other uses, such as door mirrors, glazed roofs, lamps or the like, for use in motor vehicles, to provide them with a good

hydrophobic property.

  The present invention is now described in

detail according to the Examples.

  To a zirconia sol (manufactured by Nihon Shokubai Co., Ltd), one of the fluorine-containing compounds described above was mixed to prepare the mixture so that it contained 0.2% by weight of the compound. containing fluorine, 3% by weight of Zr O 2, 50% by weight of propylene glycol methyl ether and 46.8% by weight of water, and then the resulting mixture was allowed to age in a white chamber maintained at room temperature. The mixture was applied on both sides of the glass by the immersion method, and the coating was followed by heating the coated glass. of the mixture on the glass was accomplished by removing the immersed glass vertically upward from the surface of the mixture at the rate indicated in Table 1 as shown below, providing the coating layer of

ceramic material.

  The fluorine-containing compounds used: Nonionic organofluorinated surfactant (manufactured by Mitsubishi Material Co., Ltd .: EFTOP EF-352) N-1 3- (trimethoxysilyl) propyl-N-n-propylperfluorooctyl sulfonamide (manufactured by Mitsubishi Material Co, Ltd .:

MF-160).

  The hydrophobic performance, which is represented as the contact angle with respect to distilled water, was in the range of 85 to 110 degrees. The transmittance for the coated glass was 80% to 85%. Values similar to those above were obtained after conducting the standard motor vehicle windshield test (JIS R 3212, Feature 3 7), demonstrating the excellent durability of coated glass. checked for comparison, indicating a contact angle of approximately

  degrees and a transmission factor of about 87%.

  The results are shown in Table 1.

Table 1

  1: Fluorine-containing compound used: A: Nonionic surfactant (manufactured by Mitsubishi Material Co., Ltd.: EFTOP EF-352)

  B: N-1 3- (trimethoxysilyl) propyl-N-n-

  propylperfluorooctyl sulfonamide (manufactured by Mitsubishi Material Co, Ltd: MF-160)

  2: Transmission factor of visible rays.

  Composite Speed Condi Thick Angle Factu Exem e of Re r ers of r of Dura-Conte d de de Con Con d bilit y ply nant Glass Heater layer missio é of the (mm / min fage (pm) (degree N 2 Fluor ') ( C / h)) 1 A 12 200/2 0.04 85 80-83 Good 2 B 12 200/2 0, 04 100 82-85 Good

Ex _ _ _ 20 87 -

Comp

Claims (9)

  1 hydrophobic glass pane, characterized in that it comprises a glass substrate and a ceramic material layer formed on the surface of said substrate, said ceramic material layer being the heated product of a mixture which comprises a ceramic material floor and a compound containing fluorine.   2 hydrophobic glass pane according to claim 1, characterized in that the soil of   Ceramic material is a metal oxide in soil.   3, hydrophobic window glass according to claim 2, characterized in that the metal oxide in the soil is a zirconia sol dispersed in an organic solvent, which is obtained by replacing the organic solvent with water from the soil of the soil. zirconia dispersed in water, by adding the organic solvent to the zirconia sol in water.   4 hydrophobic glass pane according to claim 1, characterized in that the fluorine-containing compound is an organofluorinated surfactant   non-ionic or N-1 3- (trimethoxysilyl) propyl-N-n-propylperfluoroactyl sulfonamide.   Hydrophobic glass pane according to Claim 1, characterized in that the concentration of the fluorine-containing compound in the mixture is set to a range of from 0.2% to 0.5% by weight, and the compound containing fluorine is bonded to the zirconia in the soil of ceramic material in the form of a group of the compound containing fluorine.   6 Method of manufacturing a window glass,   hydrophobic, as defined in one of the claims   prior art, characterized in that it comprises the steps of: coating a mixture comprising a ceramic sol and a fluorine-containing compound on a glass substrate; and   heating said coated glass substrate.   Process according to claim 6, characterized in that said mixture of sol of ceramic material and fluorine-containing compound is subjected to a step of   aging before said coating step.   The method of claim 6, characterized in that said coating step comprises immersing said glass substrate in said sol mixture of ceramic material and fluorine-containing compound, and removing said substrate from said mixture to a speed   in the range of 5 mm / min to 50 mm / min.   9 Process according to claim 6, characterized in that said heating step is carried out at a temperature ranging from 200 to 4000 C. Glass article comprising a glass substrate, on which a layer of ceramic material has been formed, said layer of ceramic material comprising the polycondensation reaction product between a material   ceramic and a fluorine-containing compound.   11 Mixture comprising a floor of ceramic material and a fluorine-containing compound.