JPH02296751A - Anti-clouding glass - Google Patents

Abstract

PURPOSE:To improve anti-clouding property and durability by laminating a thin film of Si oxide contg. a specified amt. of Na2O on the surface of glass as a base material. CONSTITUTION:An Si oxide layer contg. 5-25wt.% Na2O as a single-layer film or a laminated film having an Si oxide layer contg. 5-25wt.% Na2O as the top layer is formed by a sol-gel process or other process on the surface of glass such as optical glass or plate glass, e.g. borosilicate crown glass, flint glass or barium crown glass as a base material. Heat treatment is then carried out at about 500-550 deg.C in the air to form a thin film and anti-clouding glass is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anti-fog glass having excellent anti-fog properties over a long period of time.

(Prior Art) Generally, when the surface temperature of glass falls below the dew point, minute water droplets adhere to the glass surface, causing fogging. For example, in eyeglass lenses, goggles, car window glass, etc.
It is well known that cloudiness occurs when the surrounding temperature suddenly drops. If the glass fogs up, you won't be able to see what's ahead, which will not only make you feel uncomfortable (but may even lead to a serious accident).

For this reason, the following various techniques have been proposed for preventing glass from fogging, that is, for anti-fogging.

■Unexamined Japanese Patent Publication No. 55-154351 discloses that a thin film containing at least one of molybdenum oxide and tungsten oxide and phosphorus oxide is deposited on the surface of a glass substrate by physical vapor deposition.
A method of obtaining a hydrophilic thin film with excellent resistance to Ω by forming it by chemical vapor deposition, etc. was proposed,
Publication No. 0 proposes a method of imparting antifogging properties to glass containing P2O by contacting it with liquid or vapor of P2O5;
A method has been proposed for forming an antifogging film with excellent adhesion by applying a composition containing a sulfonic acid type amphoteric surfactant and an inorganic salt or acetate to a substrate using a lower alcohol solvent.

(Problems to be Solved by the Invention) In the method (2) above, since the thin film contains phosphorous oxide, there is a problem that the durability is poor, and the surface hardness of the film is also low.

In the method (2) above, P2O5 is easily eluted into water, resulting in poor water resistance.

The above method (2) has low film hardness and lacks long-term sustainability.

As described above, no anti-fog glass with excellent anti-fog properties and durability has been proposed so far.

The present invention has been made by focusing on such actual situation,
The purpose is to provide anti-fog glass that has both excellent durability and anti-fog properties.

(Means for Solving the Problems) The anti-fog glass of the present invention is characterized in that a thin film made of silicon oxide containing 5 to 25% by weight of Na2O is laminated on the surface of the glass substrate. The above objective is achieved.

Examples of the glass substrate used in the present invention include silicon crown, crown, flint, m-flint, barium crown, heavy barium crown, barium flint, heavy barium flint, lanthanum flint, lanthanum crown, heavy lanthanum flint, etc. Examples include inorganic glasses such as optical glass and plate glass. These optical glasses and sheet glasses are widely used as optical materials such as lenses and prisms, and as window glasses.All of these inorganic glasses are 5i0 as glass network-forming oxides.
2 and/or B2O3.

The thin film formed on the surface of the glass substrate may be a laminated film of various materials or a single layer film, but it is essential that at least the top layer of the thin film is formed from Na2O and silicon oxide. It is. Na2O is indispensable for imparting antifogging properties, and if its content is less than 5% by weight, antifogging properties will not be exhibited, and if it exceeds 25% by weight, water resistance will decrease.

Na2O may be added during the formation of the thin film, or may be added after the silicon oxide film is formed, or, for example, sodium diffusion caused by heat treatment may be used. When forming a thin film as a laminated film, examples of materials constituting layers other than the top layer include 5i02, A1201, ugo,
ZrO2, CaO1Ti02.5n02, In2O3,
WO2, MoO3, Ta2O3, HfO2, BaO1Z
Examples include nO, mullite, etc.

As a means of forming a thin film on a glass substrate, a sol is used.
Examples include a gel method, a vacuum evaporation method, a sputtering method, a CVD method, and a plating method. In particular, the true gel method, which can produce a large amount of hydroxyl groups which are hydrophilic groups, is preferred. The thickness of the thin film may be determined as appropriate depending on the application.

The surface of the anti-fog glass thus obtained exhibits excellent anti-fog properties. The reason for this is not yet clear, but it is thought to be due to the reactivity of sodium to water and the active hydrophilic groups (hydroxyl groups) of silicon. The anti-fog glass of the present invention has excellent durability and water resistance, as well as high film hardness, because the thin film does not contain phosphorous oxides as in the conventional glass.

(Example) The present invention will be specifically described below based on Examples.

1 line LLL Tetraethyl silicate (manufactured by Fullcoat) 17, 80
A hydrolyzed solution was prepared by mixing cc, an eta/- stock solution containing 2.22 cc of soda methylate (manufactured by Shuuki Fine Chemical Co., Ltd.), water, and hydrochloric acid as a catalyst. This solution was coated on the surface of quartz glass as a glass substrate, dried, and further heat-treated at 500° C. to form a thin film to obtain antifogging glass. The thickness of the thin film was approximately 0.2 μm, and analysis of the composition of the thin film revealed that S
iO3 is 79.5%, Na2O is 20.5ffif
fi%. Further, the pencil hardness was measured according to JIS K 5400 and was found to be 81+.

Next, the anti-fog properties of this anti-fog glass were evaluated. Evaluation of anti-fog properties is based on e of anti-fog glass, droplet contact angle, JISS 4030
Anti-fogging properties in high temperature areas and anti-fogging properties in low temperature areas were tested according to the following. As a result, the contact angle was 2.5 degrees, and the high temperature part
Neither the low-temperature section was tested more than 10 times.

This is because even if dew condenses on the glass surface, the contact angle between the glass surface and the dew is close to Orx, so the dew spreads uniformly over the glass surface, wets the glass, and does not cause fogging due to light scattering. I think that the. Also, 60°C190%R11
After the anti-fog glass was left inside for one month, the same evaluation as above was performed. The contact angle was 8.3 degrees, the high temperature anti-fog property was 10 times or more, and the low temperature anti-fog property was 10 times or more. From this result, it was confirmed that the product of the present invention is an anti-fog glass with excellent durability.

The same hydrolyzed solution as in Example 1 was used as a glass substrate and N
It was coated on the surface of a borosilicate glass slide glass (manufactured by Matsunami Co., Ltd.) containing 8% a2O by weight, and then dried for one day. The obtained coated glass was heat-treated at 550° C. in the atmosphere to form a thin film to obtain an anti-fog glass. Analysis of the composition of the thin film revealed that Na2O was 11.3%.
It was included.

This is considered to be the result of Na2O diffusing from the glass base material. The anti-fog properties and durability of the obtained anti-fog glass were evaluated in the same manner as in Example 1.

As a result, the initial contact angle was 3.1 degrees, and no fogging occurred over 10 times in both the high temperature and low temperature areas. The contact angle after being left for one month was 4 degrees, the anti-fogging properties at high temperatures were 7 times or more, and the anti-fogging properties at low temperatures were 10 times or more. From this result, it was confirmed that the product of the present invention is an anti-fog glass with excellent durability. Further, the pencil hardness was measured in the same manner as in Example 1 and found to be 8H.

Le ILL 5i02/Na20 = 99/1 on the quartz glass surface
A thin film having the following composition (weight ratio) was formed in the same manner as in Example 1. The antifogging properties of this glass were evaluated in the same manner as in Example 1. As a result, the contact angle was 26.5 degrees, and the high temperature part
Both the low-temperature parts became cloudy after one or more tests (no anti-fogging properties were shown).

A commercially available anti-fog coating agent (manufactured by Matsumoto Yushi Co., Ltd.) was applied to the surface of quartz glass, and the anti-fog properties and pencil hardness of this glass were evaluated in the same manner as in Example 1.

As a result, the initial contact angle was 3.3 degrees, and no fogging occurred over 10 times in both the high temperature and low temperature areas. The contact angle after being left for one month was 65.1 degrees, and both the high temperature and low temperature areas became cloudy after being used more than once. This shows that commercially available anti-fog coatings lack durability. Moreover, the pencil hardness was 2B.

(Effects of the Invention) The structure of the anti-fog glass of the present invention is as described above, and has excellent anti-fog properties and durability. Therefore, if this anti-fog glass is applied to, for example, eyeglass lenses, goggles, car window glasses, etc., fogging will not easily occur even when the surrounding temperature changes, making it comfortable to use and increasing safety. .

that's all Applicant: Sekisui Chemical Co., Ltd. Representative: Hiro 1) Kaoru -31:

Claims (1)

[Claims] 1. An anti-fog glass characterized in that a thin film made of silicon oxide containing 5 to 25% by weight of Na_2O is laminated on the surface of a glass substrate.