JPH03242351A - Production of water repellent glass - Google Patents

Abstract

PURPOSE:To homogeneously coat the surface of a glass substrate with a silicone- based water repellent dissolved in a hydrophobic solvent such as a hydrocarbon by dipping the glass substrate in the aforementioned solution while applying ultrasonic vibration to the coating solution containing the silicone-based water repellent dissolved therein. CONSTITUTION:A glass substrate is dipped in a water repellent solution containing a silicone-based water repellent dissolved therein to form a water repellent coating film on the surface thereof. The resultant water repellent coating film is then hot cured to form a water repellent film on the glass substrate and produce water repellent glass. In the aforementioned method for producing the water repellent glass, the following means are adopted. That is the glass substrate is dipped in the water repellent solution while applying ultrasonic vibration to the water repellent solution in coating the water repellent coating film to form the water repellent coating film. If the ultrasonic vibration applied to the coating solution is within the range of 10-50kHz, the objective homogeneous coating film is preferably formed in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Use] The present invention relates to a method for manufacturing water-repellent glass used in vehicles and the like.

[Prior Art] Conventionally, as a method for applying silicone-based water repellent polymers to glass substrates, the method of immersing the glass substrate in a water repellent solution has been widely used because it is easy to control the thickness of the coating film at a constant level. It is. For example, in Japanese Patent Application Laid-open No. 1-126244, a glass substrate is immersed in a solution of polydimethylsiloxane dissolved in a liquid hydrocarbon at room temperature, and then pulled up.
A method for producing water-repellent glass is disclosed, which is cured by heat treatment to form a water-repellent film.

However, in the above method, since the hydrocarbon solution is hydrophobic, it has poor wettability to highly polar glass, and it is often difficult to uniformly coat the surface of the glass substrate. Additionally, when a silicone-based polymer with a high degree of polymerization is used to increase water repellency, the viscosity of the polymer is high and the viscosity of a solution in which it is dissolved increases, making the coating film formed even more uneven in thickness. Prone. Therefore, it is necessary to repeat dipping or adjust the film thickness by wiping or the like in order to form a uniform film thickness, making the process complicated and undesirable.

On the other hand, polar solvents that have good wettability with glass substrates cannot be used as coating solvents because they do not dissolve the water repellent.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to uniformly apply a silicone-based water repellent dissolved in a hydrophobic solvent such as a hydrocarbon to the surface of a glass substrate.

[Means for Solving the Problems] The method for producing water-repellent glass of the present invention involves immersing a glass substrate in a water-repellent solution in which a silicone-based water repellent is dissolved to form a water-repellent coating on the surface. In a method for producing water-repellent glass, the water-repellent coating film is then heated and cured to form a water-repellent film on a glass substrate, in which ultrasonic vibration is applied to the water-repellent solution during application of the water-repellent coating film. The water repellent coating film is formed by immersing the glass substrate while adding water repellent.

The feature of the present invention is to form a uniform and highly adhesive water-repellent film on a glass substrate by immersing the glass substrate in a coating solution containing a water-repellent agent while applying ultrasonic vibrations to the solution. There is a particular thing.

When ultrasonic vibrations are applied to the coating solution, the solution locally becomes high temperature and high pressure, and a large amount of energy is applied to the solution, causing it to collide with the immersed glass surface. Due to the collision of this high-energy solution on the glass surface, the water repellent present in the solution is adhered and fixed to the glass surface, and even a solution with poor wettability can be uniformly applied. As a result, a uniform coating film can be formed on the glass surface.

The ultrasonic vibration applied to the coating solution is preferably in the range of 10 to 50 KH7 because a uniform coating film can be formed in a short time.

As the water repellent, silicone-based polydimethylsiloxane, polydiphenylsiloxane, polyphenylmethylsiloxane, etc. can be used.

According to this method, even a water repellent having a high degree of polymerization such as a viscosity of 10 to 10 million CS can be uniformly applied.

Any solvent that can dissolve the water repellent agent can be used. For example, hydrocarbons such as hexane, heptane, octane, toluene, and banzene can be used. The water repellent is preferably used dissolved in a solvent at a concentration of 1 to 10% by weight. In the dipping method, the thickness of the coating film can usually be controlled by adjusting the concentration of the water repellent solution. Therefore, also in the present invention, the film thickness can be easily adjusted.

After coating, the glass substrate is pulled up from the dipping solution, dried to remove the solvent, and then heated to harden the coating film.

In this case, the coating film begins to harden from the glass surface. If an uncured portion remains on the upper surface of the cured film after curing, the uncured portion can be completely wiped off using the above-mentioned solvent to form a water-repellent film of a predetermined thickness.

[Operation] According to the method of the present invention, a glass substrate is immersed in a water repellent coating solution while applying ultrasonic vibrations.

Therefore, when the coating liquid is vibrated by ultrasonic waves and cavitation occurs, the solution becomes locally high in temperature and pressure, and collides with the glass surface with a large amount of energy. Furthermore, since the number of collisions with the glass increases, the water repellent dissolved in the solution easily adheres to the glass surface, and the adhesion of the coating film increases, allowing it to be applied uniformly.

Therefore, it is possible to uniformly coat a glass surface using a coating solution made of hydrocarbon or the like having poor wettability or a water repellent having high viscosity. Therefore, the water-repellent film formed by curing the obtained coating film is also uniform, resulting in water-repellent glass with no unevenness. Furthermore, the water-repellent film formed by this method has better adhesion than that formed by conventional dipping, and the cured film has increased durability and water repellency can be improved.

[Example] Hereinafter, this will be explained in detail using examples.

The surface of a glass substrate (70xl 50xt 3.1 mm) was polished and cleaned using a cleaner containing a polishing compound.

The water repellent coating solution was prepared by diluting polydimethylsiloxane having a viscosity of 10 to 10 million C5 with n-hexane to 1 to 10% by weight.

As an ultrasonic oscillator, we modified the vibrator of a commercially available ultrasonic cleaner to be able to apply high frequencies of 0 to 50KH7 from an external high-frequency oscillator, and placed it in a dipping container to apply ultrasonic waves to the coating solution. I added it.

The above glass substrate was immersed in the above coating solution having a concentration of 1 to 10% by weight, and ultrasonic vibrations of 10 to 50 KH2 were applied for 1 minute. The glass substrate was then pulled up after the solution was allowed to stand until the vibrations on the surface of the solution stopped. This glass substrate was dried in a drying oven at 70° C. for 15 minutes to remove the solvent.

The coated film was then cured by heating at 300° C. for 20 minutes. Thereafter, the uncured portion remaining on the surface of the cured film was wiped off with a cloth impregnated with hexane.

The contact angle of the obtained water-repellent film was 95 to 1 on average over the entire surface of the film.
00' showed good water repellency.

On the other hand, when cured under the same conditions except that the same coating solution was used and dip coating was performed without applying ultrasonic vibration, the contact angle of the water-repellent film was small and non-uniform, ranging from 60 to 90'.

Further, when a coating liquid having a concentration of 1 to 10% by weight is applied to a glass surface by wiping in a rubbing manner, a water-repellent film having water repellency comparable to that of the present invention is formed.

For the three types of water-repellent glasses obtained above, the contact angles before and after the friction test shown in Table 1 were measured to investigate the relationship between the application method and water repellency.

The contact angle is measured using a contact angle meter CA-A manufactured by Kyowa Interface Science.
The contact angle of the water-repellent film with water was measured using a mold.

The abrasion test was carried out using a Gakushin type flat abrasion tester manufactured by Daiei Kagaku Seiki Seisakusho, the friction element was covered with flannel cloth, and the friction element was rubbed 100 times at a load of 12009.

Table 1 shows the average value of the contact angles of the entire surface of the water-repellent coating before and after the abrasion test.

When the film was formed using the conventional immersion method, the value before the test was 60.
90", which is low, but after the friction test, it has further decreased to 5° to 60". On the other hand, in the method using ultrasonic waves of the present invention, it is the same as when applied by rubbing it into the glass surface with wiping. The initial value before the test is 95 to 100'', and even after friction it is 90 to 95 degrees, which shows little deterioration, making it a water-repellent glass with good adhesion to the glass surface and good durability.

[Effects] According to the manufacturing method of the present invention, a uniform water-repellent film can be formed on the glass surface by the dipping method even if the coating solution has poor wettability on the glass surface.

Therefore, the coating amount can be easily controlled by concentration, which is a feature of the dipping method, and the applied coating film can be cured to form a uniform water-repellent film with good reproducibility. Further, even with a highly viscous water repellent, a water repellent film can be formed by this method. The resulting water-repellent glass has improved water repellency compared to conventional glass.

Claims (1)

[Claims] (1) A glass substrate is immersed in a water repellent solution containing a silicone-based water repellent to form a water repellent coating on the surface, and then the water repellent coating is heated and cured to form a water repellent coating. In a method for manufacturing water-repellent glass formed on a glass substrate, the glass substrate is immersed in the water-repellent solution while applying ultrasonic vibration when applying the water-repellent coating film to form a water-repellent coating film. A method for producing water-repellent glass characterized by: