KR19990011519A - Manufacturing method of water repellent glass by spray coating - Google Patents

Abstract

The present invention relates to a method for producing a water-repellent glass by spray coating, and more particularly, to form a silica base layer on the surface of a glass substrate and apply a fluoroalkylsilane (FAS) thereon to form a water-repellent layer. In manufacturing the water-repellent glass of structure, spray coating and heat-treating the temperature and humidity conditions and the distance between glass substrate and spray nozzle in the specific range when forming the silica base layer and water-repellent layer to large area or curved glass such as automobile glass or building glass. The present invention relates to a method for producing a water-repellent glass by spray coating that imparts water repellency and durability.

Description

Manufacturing method of water repellent glass by spray coating

The present invention relates to a method for producing a water-repellent glass by spray coating, and more particularly, to form a silica base layer on the surface of a glass substrate and apply a fluoroalkylsilane (FAS) thereon to form a water-repellent layer. In manufacturing the water-repellent glass of structure, spray coating and heat-treating the temperature and humidity conditions and the distance between glass substrate and spray nozzle in the specific range when forming the silica base layer and water-repellent layer to large area or curved glass such as automobile glass or building glass. The present invention relates to a method for producing a water-repellent glass by spray coating that imparts water repellency and durability.

Glass used in the state of being exposed to the outside, for example, vehicle safety glass, glass for transportation equipment including aircraft, building glass, mirrors, and household glass are often contaminated with rain and various moisture on the surface thereof. In this case, because the view is poor, a technique of providing a water repellent function to the glass surface is used to prevent this.

In order to impart a water repellent function to the glass surface, the surface energy of the glass surface must be made low. For this purpose, the glass surface is treated with a material having a low surface energy (hereinafter referred to as a water repellent). In this regard, the soda-lime glass produced by the conventional method exhibits a contact angle of about 20 ° to water, but the excellent water-repellent glass sample exhibits a contact angle of 100 ° or more.

Generally, hydrocarbon-based compounds, silicon-based compounds, chlorine compounds and fluorine compounds are used as water repellents. The most excellent among them is a fluoroalkylsilane (FAS) -based water repellent. FAS-based water repellent agent may, and the critical surface tension of 20 is a dyn / ㎝ or less of water and a polar solvent, as well as having an emitting FIG oil properties, the component that gives the lowest surface energy, CF ₃ or CF ₂ is abundant, It also has a linear structure, which increases the density of the water repellent.

Water repellents that impart water repellency to glass surfaces have two types of functional groups, one of which reacts with silanol groups (R ₃ Si-OH) on the glass surface to form a solid siloxane bond (Si-O-Si). Functional groups to be produced, for example, methoxysilane group (-Si (OCH ₃ ) ₃ ), ethoxysilane group (-Si (OC ₂ H ₅ ) ₃ ), methylchlorosilane group (-SiCH ₃ Cl ₂ ) and isocyanate group (-NCO), the other functional group is composed of a fluorocarbon group (CF ₃ (CF ₂ ) _X- ) which is in contact with the atmosphere and can impart hydrophobicity to water.

However, when a fluorine compound is immediately applied to a general soda-lime glass without forming an intermediate layer, there is a problem in that the water repellency is deteriorated with use time due to the elution of an alkali component in the glass. Therefore, it is necessary to coat the dense and rigid silica film before the water repellent film while suppressing alkali elution of the glass. In particular, the water-repellent function of glass in poor conditions against the external environment, such as automotive glass, is insufficient by the direct treatment of the water repellent, and in particular, additional functions for durability should be considered. In addition to the resistance to abrasion, the resistance to scratches, Durability such as resistance to wind and chemical components, resistance to ultraviolet rays such as sunlight, and temperature resistance to four seasons should be sufficient. In other words, the durability of the water-repellent function is long lasting so that the user can see the functional benefits of the water-repellent glass without inconvenience.

In the past, efforts to improve the durability of water repellent glass have been improved by various inventors at various angles. Among them, in order to improve the durability of water-repellent glass, it is most common to form a silica layer before forming a water-repellent film on the surface of the glass substrate. Such silica coating methods include dip coating, spin coating, and dropping. (flow coating), chemical vapor deposition (CVD), etching (plasma) and the like are used.

Among them, Japanese Patent Application Laid-Open Nos. Hei 5-213622, Hei 6-16455, Hei 5-310444, Hei 7-330378 and Hei 8-239242 have a method of producing water-repellent glass by silica coating by an impression method. Is disclosed. The coating method by the pulling method is a method in which a glass is deposited on a surface of a glass by depositing a coating solution for forming a silica layer. This method has the advantage of simple process, whereas a large amount of coating solution is required and the coating solution is contaminated. The coating solution must be exchanged, and due to the disadvantage that both sides are coated, there is a disadvantage in that one side cannot be selectively coated. In addition, this method is easy to apply to flat glass, but in the case of curved glass, there is a problem in that the distribution of the coating liquid varies depending on the curved surface. have.

Further, Japanese Patent Laid-Open Nos. 4-160039, 5-24885, 5-24887, U.S. Patent No. 5,266,358, and European Patent Publication No. 0476510A1 disclose a method of forming a silica layer by a rotation method. . The rotating method is a method of dropping a coating liquid onto a glass substrate to rotate the glass substrate at a high speed to spread the coating liquid evenly on the surface of the glass substrate by centrifugal force.However, if a dust, etc. gets on the substrate, defects occur during coating. This causes a problem that the entire substrate is inhomogeneous in coating. This method is suitable for substrate sizes such as CRT glass for televisions, but it is difficult to rotate glass substrates at high speed for large-area and three-dimensional curved glass such as automotive glass. Due to problems such as coating state, it is not suitable for mass production.

On the other hand, Japanese Patent Laid-Open Nos. 5-307822 and 7-207255 disclose a method of forming a silica layer by a dropping method. The drop method is a method of vertically moving and coating the coating solution for forming a silica layer from the top of the glass substrate while the glass substrate is placed vertically. On the other hand, there is a problem that the process speed is slow and the loss of the coating solution is excessive. Especially in the case of curved glass, there is a problem that the thickness of the coating film is not uniform, and there is a high possibility that a peeling state occurs after coating. In addition, the problem that the coating film becomes very thick at the lower end of the glass is likely to occur. This problem has a problem of causing a decrease in the film quality and peeling phenomenon after coating and firing.

Japanese Laid-Open Patent Publication No. 8-119678 discloses a method of forming a silica layer on glass by chemical vapor deposition (CVD), but CVD is a difficult process and uses expensive equipment to coat large areas of glass. There are many restrictions on the use of tops.

In order to improve the above problems, the present invention provides a silica sol solution on the surface of a glass substrate by spray coating the silica sol solution at high humidity and low temperature during the manufacture of water-repellent glass, and then heat-treating the silica film on the surface of the glass substrate on which the silica layer is formed. It is an object of the present invention to provide a method for producing a water-repellent glass by spray coating to increase the durability by coating a water-repellent layer on a large area or curved glass, such as automotive glass or building glass by spray-coating a water repellent.

1 is a schematic view showing the configuration of a coating apparatus including a spray gun,

2 is a view showing a coating pattern of the spray gun.

Explanation of symbols for the main parts of the drawings

1 coating machine 2 glass substrate

3: coating solution tank 11: spray gun

12: coating solution transfer line 13a: spray air injection line

13b: compressed air injection line

The present invention provides a method of manufacturing a water-repellent glass having a double-layered structure having a silica layer and a water repellent layer formed on a glass substrate surface

The silica sol solution and the water-repellent solution prepared separately are sprayed onto the glass substrate using a spray coating method to form a silica layer and a water repellent layer. The distance between the glass substrate and the spray nozzle is 10-20 cm, 20-40 ° C. and humidity. It is characterized by spray coating under 55% or more of conditions to form a silica layer and a water repellent layer, respectively.

Referring to the present invention in more detail as follows.

In the method of manufacturing the water-repellent glass according to the present invention, the coating solution, that is, the silica sol solution and the water-repellent solution are sprayed by a spray coating method under specific conditions, and is characterized by heat treatment thereof.

Spray coating machine 1 used in the present invention is a spray gun 11, the coating solution transfer line 12 for transferring the coating solution to the spray gun, spray gun and coating solution tank as shown in Figure 1 attached (3) includes a sprayed air injection line 13a and a compressed air injection line 13b. Spray coating machine 1 in the present invention can be moved up, down, left and right, the injection amount of the coating solution is adjusted by the air pressure of the spray air injection line (13a) and compressed air injection line (13b).

The coating solution for forming the silica layer is added with distilled water and hydrochloric acid in order to cause hydrolysis in the solution of tetraethoxysilane (TEOS) in ethanol solvent, 70 ~ 95 g of ethanol per 1 g of tetraethoxysilane, water 0.5-5 g, hydrochloric acid 0.001-5 g are added, stirred, and aged for 1 day in a thermostat maintained at 60 ° C.

In addition, a coating solution for forming a water repellent layer is conventional, and distilled water and hydrochloric acid are added to cause hydrolysis in a solution in which fluoromethoxysilane is dissolved in a solvent such as isopropyl alcohol. 40 to 60 g of propyl alcohol, 0.005 to 0.25 g of water, 0.05 to 0.5 g of hydrochloric acid are added, stirred, and aged for 1 day in a thermostat maintained at 60 ° C. At this time, the reason for the hydrolysis and polycondensation reaction of the water repellent is to maximize the siloxane bond (Si-O-Si) by promoting the reaction of the fluoroalkylsilane group and the silanol group on the surface of the silica layer.

Referring to the spray coating method of each coating solution according to the invention in more detail as follows.

After the coating solution prepared above is put into the coating solution tank 3, air pressure is applied through the compressed air injection line 13b. The coating solution is transferred to the spray gun 11 through the coating solution transfer line 12 by the air pressure applied to the coating solution tank 3.

In order to spray the coating solution, air of an appropriate pressure is delivered to the spray gun 11 through the spray air injection line 13a.

In this way, the coating solution introduced into the spray gun 11 is sprayed radially while being changed into a spray form by the air pressure radiated from the spray nozzle attached to the spray gun 11. When spray coating, the injection amount of the coating solution decreases when the pressure of air delivered to the injection nozzle increases, and the injection amount increases when the air pressure delivered to the coating solution tank 3 increases. That is, the adjustment of the injection amount according to the silica coating is made by adjusting the air pressure delivered to the injection nozzle and the coating solution tank 3, and when the amount of coating solution is small and the amount of air is small, the amount of injection is increased. The larger the amount, the lower the injection amount.

On the other hand, the thickness of the coating layer is determined by the distance between the injection nozzle attached to the spray gun 11 and the glass substrate 2, and the proper pressure when the distance between the injection nozzle and the glass substrate 2 is 10 to 20 cm. By spraying the coating solution by the distribution can minimize the coating thickness and control the volatilization rate of the coating solution. That is, even if the same amount of coating solution is sprayed, if the distance is too close, the amount of coating solution increases and the coating film becomes thicker than necessary, so that peeling phenomenon occurs easily after firing, and if it is too long, the coating solution amount becomes less. The thickness of the film becomes thinner and brings uneven coating state to the surface.

This coating pattern can be controlled through a robot capable of three-dimensional programming.

The area coated by one movement in the spray coating is somewhat different depending on the type of spray gun 11 used, the distance between the glass substrate and the spray nozzle, the coating solution and the air pressure, etc., but the diameter is generally in the range of 2 to 10 cm. In the large-area coating has to be coated several times according to the coating pattern as shown in the accompanying drawings.

That is, the zigzag method of spraying the coating solution while moving to the right (or left) from the first point, and moving to the lower axis about 2 to 5 cm from the point after the injection is made, and then spraying while moving to the left (or right) again. Repeating to coat the entire glass substrate.

When the spray coating up and down, left and right more than several times, the first coating surface and the second coating surface overlaps. This overlapping phenomenon is difficult to change immediately after coating and tends to occur after baking at 200 to 350 ° C. As the thickness difference between the first coating surface and the second coating surface occurs, the separation (peeling) of the silica layer after firing and the surface state are not clean, that is, they become cloudy, and there are spot and hole defects. Occurs.

When coating is performed while the spray nozzle moves in a zigzag manner, as shown in FIG. 2, the coating surface is unevenly formed due to a difference in coating thickness between the switching portions and the central portions of both ends of the glass substrate 2. It may be preferable that the switching portions at both ends of the glass substrate 2 are located outside the glass substrate 2.

In the present invention, the overlapping phenomenon shown in the large-area glass coating by the spray method was solved by controlling the humidity, particularly in the temperature and humidity during coating.

When the coating is applied in a low humidity state, that is, in a dry state, a difference in thickness between the first coating surface and the second coating surface occurs due to the volatilization speed difference, which causes a flaw of the surface that becomes cloudy after firing, which results in a clean surface. This is a problem for automotive glass that should have. However, if the coating is performed in a high humidity state, the volatilization speed of the coating solution is slowed down, so that the initial coating solution at the boundary of the continuous coating surface is sufficiently flattened by its own surface tension so that defects do not occur. Coating is possible. Therefore, the humidity is maintained at 55% or more, preferably 80% or more. When the spray nozzle is moved, the overlapping part occurs on the specimen. In low temperature or low humidity atmosphere, the overlapping part is bad in appearance. The height difference of the glass substrate 2 was adjusted, and the coating of glass which has a flat surface and a curved surface shape was also attained.

On the other hand, in the curved part of the glass substrate 2, if the spray nozzle is moved only in two dimensions, the coating solution is caused by the difference between the spray nozzle and the glass substrate 2 at the central portion of the glass substrate 2 and the curved end thereof. Since the amount of is different, it is easy to cause defects due to thickness differences. In the present invention, by introducing a three-dimensional robot system to move the spray gun 11 in three dimensions to move at the same curvature as the curved surface of the glass substrate 2 to maintain a constant distance between the spray nozzle and the glass substrate (2). .

In addition, after spraying the silica coating solution on the glass substrate (2), heat treatment at 200 ~ 350 ℃ for 30 minutes at a temperature increase rate of 7 ℃ / min, a solid Si-O-Si siloxane crosslinked layer on the surface of the glass substrate (2) The silica layer is formed. The thickness of the coating of the silica layer and the coating film measured after firing it was 600-1,500 kPa.

In addition, even after spraying a water-repellent agent-containing coating liquid on the silica layer to form a water-repellent layer by heat treatment under the same conditions as described above, the coating of the water repellent layer and the thickness of the coating film measured after firing was 700 ~ 1,600Å.

Although this invention is demonstrated in detail based on an Example, this invention is not limited to an Example.

Example: Spray Coating

1. Silica layer formation

Tetraethoxysilane (TEOS, 31.2g) and ethanol (257.94g) were mixed and hydrochloric acid (0.06g) and water (10.8g) were added to the mixed solution which was stirred for 30 minutes and stirred for 2 hours. It was aged for 1 day in a maintained thermostat and used as a silica coating solution.

After the windshield was cleaned, the distance between the spray nozzle and the glass substrate was maintained to 15 cm. The moving speed of the spray nozzle was 40 cm / sec to spray the coating solution prepared above. The coating was performed at 25 ° C. under a humidity of 85% and the coating was performed by adjusting the air pressure and the solution pressure to 0.7 bar and 0.5 bar, respectively. The coating is carried out in such a way that the spray nozzle moves from left to right at the top of the specimen at a speed of 40 cm / sec, then to the bottom of 3 cm, then repeatedly moves from right to left at the same speed as above and again to the bottom of 1 cm. The whole was allowed to be coated.

Then, the coated glass substrate was heat-treated for 30 minutes at a temperature of 300 ° C. at a heating rate of 7 ° C./min.

2. Water repellent layer formation

On the silica layer formed above, a water repellent layer was formed by the following method.

As a water repellent, fluoromethoxysilane (3 g), isopropyl alcohol (150 g), hydrochloric acid (1 g) and distilled water (0.2 g) were mixed and aged at 60 ° C. for 2 days, and then used as a water repellent coating solution. .

The glass substrate 2 having the silica layer formed thereon was coated using the spray coating method under the same conditions as the silica coating method. The water-repellent coated glass substrate was heat dried at 150 ° C. for 1 hour.

Comparative Example : Dip Coating

The soda lime glass substrate was cut to 50 × 50 cm (thickness 0.1 cm), and then washed first with a surfactant, and then immersed in distilled water for 15 minutes with an ultrasonic cleaner.

After the third washing with acetone and put in a dryer at 120 ℃ dried and immersed the specimen in the sol solution for 30 seconds using a motor driven dip coater and was raised at a rate of 30 cm / min. The glass substrate was heat-treated for 30 minutes at a temperature of 300 ℃ and the temperature increase rate was 7 ℃ / min. The silica forming solution and the water repellent were prepared under the same conditions as in the above examples.

Experimental Example

The physical properties of the coated glass substrates in Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

The contact angle was measured by the droplet drop method using a contact angle measuring instrument (model CA-X of Ltk japan), and the average value was taken after five measurements at different positions.

The wear resistance was measured by using a large area wear tester, and the contact angle was measured after 20,000 round trip tests at a reciprocating speed of about 2 seconds with a load of 1 kg / cm on both sides of the specimen.

The alkali resistance test was performed by dipping the specimen in 1N sodium hydroxide solution for 6 hours and then measuring the contact angle. The acid resistance was measured by dipping the specimen in 1N hydrochloric acid solution for 6 hours and measuring the contact angle. After soaking the specimen for 2 hours, the contact angle was measured and evaluated by measuring the decrease in the contact angle.

Abrasion resistance was measured after 100 to 1,000 rotations using a taver wearer (5150 taber abraser, USA), and the field of view was evaluated by a blur meter (BYK gardner, KS L 2007).

division Example Comparative example Appearance Great Great Initial contact angle (°) 118 109 Wear resistance 99 85 Acid resistance 116 99 Alkali resistance 109 97 Heat resistance 117 100 Changes in Contact Angle and Cloudiness after Taber Abrasion (100 to 1,000 Times) 100 times Contact angle (°) 105 98 Cloudiness (ΔH) 0.6 0.7 300 times Contact angle (°) 99 89 Cloudiness (ΔH) 0.7 0.8 500 Contact angle (°) 91 89 Cloudiness (ΔH) 0.8 1.1 1,000 Contact angle (°) 83 78 Cloudiness (ΔH) 1.02 1.23

As shown in Table 2, the performance of the examples by the spray coating method in most of the performance was superior to the comparative example by the pulling method.

The glass substrate coated by the spray coating method of the present invention has an excellent appearance and can be used for various applications such as automobile safety glass, transportation glass including aircraft, building glass, mirror and household glass, and excellent water repellency and water repellency. It can be seen that the durability and wear resistance is excellent.

Claims (2)

In the method of manufacturing a water-repellent glass having a double-layered structure having a silica layer and a water repellent layer formed on the surface of the glass substrate, The silica sol solution and the water-repellent solution prepared separately are sprayed onto the glass substrate using a spray coating method to form the silica layer and the water repellent layer. The distance between the glass substrate and the spray nozzle is 10-20 cm, 20-40 ° C. and humidity. Spray coating under the condition of 55% or more to form a silica layer and a water repellent layer, respectively. The method of claim 1, wherein the spray nozzle moves in three dimensions with the same curvature as that of the curved glass substrate.