JP2005330165A - Antifogging glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide antifogging glass having a hard and transparent antifogging film formed on the surface of the glass, which has an excellent antifogging property, keeps it for a long time, and has a sufficient adhesiveness to the glass. <P>SOLUTION: The antifogging glass is manufactured by forming an antifogging film on the surface of a glass substrate, which is formed by applying a liquid composition for antifogging containing at least one kind of water-soluble resin selected from the group consisting of polyvinyl alcohol, polycarboxylic acids with an acid value of 600-950, an amorphous metal oxide, and a zirconium-based crosslinking agent on the surface of the glass substrate and heating for crosslinking. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antifogging glass coated with an antifogging film capable of maintaining good antifogging properties over a long period of time and a method for producing the same.

In general, when the surface temperature of the glass falls below the dew point, fine water droplets adhere to the glass surface and cause fogging. For example, fogging of glass surfaces such as automobile windows and bathroom mirrors obstructs the field of view, which impairs the functions of the windows and mirrors and may cause uncomfortable feelings or accidents. When the endoscope lens or dental dental mirror becomes clouded, it becomes an obstacle to accurate diagnosis, surgery, and treatment. If the cover glass on the instrument panel is cloudy, it will be difficult to read data.
Thus, the request | requirement with respect to the antifogging of the glass surface exists in a wide technical field, and various antifogging techniques have been proposed until now.

Among these various antifogging techniques, a method of forming a hydrophilic film on the surface of a glass substrate is most commonly used together with a method of increasing the surface temperature of the glass substrate.
When a hydrophilic coating is formed on the surface of the glass substrate, the surface free energy of the coating is increased, and even if the glass surface temperature falls below the dew point, moisture present near the glass surface is first promptly deposited on the hydrophilic coating. The anti-fogging effect is exhibited because it is difficult to form water droplets. In addition to good anti-fogging properties, the anti-fogging film formed on such glass surfaces has excellent adhesion to glass, hard and scratch-resistant, excellent wear resistance, and good anti-fogging over time. Maintenance of sex is required.

As an antifogging method for forming a hydrophilic coating on the surface of a glass substrate, there have been many proposals for obtaining a hydrophilic coating from the following inorganic materials.
Patent Document 1 proposes a bathroom antifogging mirror having a self-cleaning function in which a layer containing an alkali metal silicate (water glass) is formed. Since the layer containing an alkali metal silicate is a glassy smooth layer, it is difficult to get dirty and has a self-cleaning function by an alkali ion component. However, although the initial hydrophilicity is good, water glass is eluted over time and the hydrophilicity (antifogging property) disappears, and the hydrophilic film made of an inorganic material has a disadvantage that it is brittle. .
Patent Document 2 describes a method of coating a glass surface with an antifogging aqueous solution in which water glass and boric acid are dissolved and heating to form a film, and proposes an inorganic antifogging agent having a low filming temperature. Is. However, the antifogging maintenance property is better than that of a single water glass film, but it is not sufficient, and the film is brittle because the baking temperature is low.
Patent Document 3 discloses an antifogging mirror in which hydrophilic ultrafine particles are dispersed in a matrix made of an alkoxysilane hydrolyzate and water glass on the mirror surface and coated with a hydrophilic coating. Although this product has good initial antifogging property, since the film is brittle, the antifogging maintenance property is not sufficient, for example, the coating film peels off under the use environment.
Patent Document 4 discloses a photocatalytic hydrophilic member in which a surface layer containing a photocatalytic titanium oxide sol and an amorphous metal oxide is formed. Since the surface becomes hydrophilic in response to photoexcitation of the photocatalyst, the surface can be maintained at a high degree of hydrophilicity. However, a high temperature is required for baking the film, and light irradiation is necessary each time to obtain sufficient hydrophilicity.

  As described above, these conventional techniques require high temperatures for film formation and baking, or because the coating is brittle or insufficiently adherent to glass, the coating peels off during use and has anti-fogging properties. There have been problems such as a decrease, a hydrophilic coating dissolved in water, and good antifogging properties cannot be maintained over a long period of time, or antifogging properties will not be exhibited unless exposed to light.

JP 2000-32212 A JP 2000-203883 A JP 2001-372111 A JP 2001-129916 A

  In view of such a situation, the present invention is capable of forming an antifogging film that has sufficient adhesion to glass and is not brittle even at a low temperature of 200 ° C. or lower, and is itself long-term even in a use environment such as a bathroom. An object of the present invention is to provide an antifogging glass using a liquid composition for antifogging which can form a coating film capable of maintaining good antifogging properties on the glass surface and a method for producing the same.

  The present inventors apply a liquid composition for anti-fogging containing a specific water-soluble resin, an amorphous metal oxide, and a zirconium-based crosslinking agent on the surface of a glass substrate, and by heating to form a film, It has been found that the above object can be achieved. An amorphous metal oxide such as water glass as a good anti-fogging component is dispersed and fixed in a poorly water-soluble film in which the hydroxyl group or carboxyl group of a water-soluble resin is crosslinked and cured by a zirconium-based crosslinking agent by heating at 200 ° C. or lower. Therefore, it is considered that the antifogging component is gradually released to the surface over a long period of time to form an antifogging film having high antifogging maintenance property.

That is, the present invention provides at least one water-soluble resin selected from the group consisting of polyvinyl alcohol, a polycarboxylic acid having an acid value of 600 to 950, an amorphous metal oxide, and a zirconium-based crosslinking agent on the surface of a glass substrate. An anti-fogging glass having an anti-fogging film formed thereon is provided by applying and heating a liquid composition for anti-fogging.
Moreover, this invention provides the said anti-fogging glass whose glass base material is a mirror which provided the reflection layer in the back side which has not formed the anti-fogging film | membrane.
Furthermore, the present invention relates to an antifogging glass comprising a step of coating the surface of a glass substrate with the antifogging liquid composition to form a coating layer, and a step of heating and drying the coating layer to form a film. A manufacturing method is provided.

  The antifogging film obtained by the present invention has a structure in which an amorphous metal oxide such as water glass is dispersed and fixed in a cross-linked water-soluble resin, and therefore has good adhesion and water resistance to glass. Does not peel off or dissolves in water, and the antifogging properties are not lowered, and the antifogging components such as water glass are gradually released, so that good antifogging properties are maintained over a long period of time. In addition, since the organic material is crosslinked, the film is hard and brittle even though it is formed at a heating temperature as low as 200 ° C. or less.

The present invention is described in detail below.
Examples of the glass substrate used in the present invention include flat plates and shapes such as soda lime glass, lead glass, and borosilicate glass. Moreover, what was processed into the mirror etc. which provided the reflection layer in the back surface of these glass is also included.

  Polyvinyl alcohol as a water-soluble resin used in the present invention has a number average molecular weight (obtained by conversion using a calibration curve prepared with standard polystyrene by gel permeation chromatography) of 10,000 or more completely to partially saponified. Polyvinyl alcohol is mentioned. In particular, polyvinyl alcohol having a saponification degree of 90% or more is preferable. If the degree of saponification is less than 90%, the antifogging property may be inferior.

Another water-soluble resin that can be used in the present invention is a polycarboxylic acid having an acid value of 600 to 950. When the acid value is less than 600, the coating film is often inferior in transparency and antifogging properties, and cannot be used in the present invention. The acid value is more preferably 700 to 950.
As such polycarboxylic acid, polymethacrylic acid, polyacrylic acid, methacrylic acid / acrylic acid copolymer, polymaleic acid, acrylic acid / maleic acid copolymer, and mixtures thereof are preferable, among which polyacrylic acid Is particularly preferred.
Further, the polycarboxylic acid may contain other monomer units within a range satisfying an acid value of 600 to 950. Examples of such comonomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, and 2-ethylhexyl acrylate. Acrylic acid esters such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, methacrylic acid 2 -Methacrylic acid esters such as human hydroxyethyl and 2-hydroxypropyl methacrylate; aromatic vinyl monomers such as styrene and vinyltoluene;

The polymerization method of the polycarboxylic acid is not particularly limited, but is preferably simple by solution polymerization, an organic solvent such as methanol, ethanol, isopropanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, carbitol, butyl carbitol, or the like. Water can be used as the reaction solvent or diluent solvent.
Examples of the polymerization initiator include peroxide radical polymerization initiators such as benzoyl peroxide and ditertiary butyl peroxide, and azo radical polymerization initiators such as 2,2′-azobisisobutyronitrile and azobisvaleronitrile. , Ammonium peroxodisulfate and the like can be used.

  The number average molecular weight of the polycarboxylic acid used in the present invention is preferably 10,000 to 100,000, more preferably 10,000 to 50,000. If the number average molecular weight is less than 10,000, problems are likely to occur in the strength and durability of the coating film, and if it exceeds 100,000, the viscosity of the resin solution increases and problems in workability are likely to occur.

  The amorphous metal oxide used in the present invention includes at least one of amorphous silica such as colloidal silica, primary glass 5 to 100 nm, water glass, amorphous titanium oxide, titanium hydroxide, amorphous alumina, and aluminum hydroxide. Of the mixture. Among these, water glass is preferable from the viewpoint that a high antifogging effect can be obtained and that the antifogging effect can be maintained.

In the present invention, a zirconium-based crosslinking agent is used as a crosslinking agent for crosslinking the water-soluble resin. Zirconium-based crosslinking agents are water-soluble, have low toxicity, and have high transparency in the crosslinked coating. Specific examples include ammonium zirconium carbonate, alkali metal fluorozirconates such as K ₂ ZrF ₆ and K ₂ CrF ₆ , soluble fluorozirconates such as (NH ₄ ) ₂ ZrF ₆ and H ₂ ZrF ₆ , zirconium fluoride, oxidation Zirconium etc. are mentioned. Among these, ammonium zirconium carbonate is preferable from the viewpoint of the stability of the antifogging liquid composition.

  The solvent of the antifogging liquid composition of the present invention is preferably mainly composed of water from the viewpoints of hygiene in the coating environment, danger of ignition, and the like. When it is necessary to improve paintability, in addition to water, methanol, ethanol, n-propanol, isopropanol, ethylene glycol, diacetone alcohol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol, 1-ethoxy-2- A solvent freely mixed with water, such as alcohol solvents such as propanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and 2-butoxyethanol can be used in combination.

The water-soluble resin occupying the solid content of the antifogging liquid composition is preferably 5 to 70% by weight of the solid content. Even if it exceeds 70%, even if it is less than 5%, the antifogging maintenance property is not sufficient.
The amorphous metal oxide occupying the solid content of the antifogging liquid composition is preferably 25 to 80% by weight of the solid content. If it exceeds 80%, the coating will be whitened and the transparency will be lowered, or the membrane will be brittle. If it is less than 25%, the antifogging maintenance property is not sufficient.
The zirconium-based crosslinking agent occupying the solid content of the antifogging liquid composition is preferably 2 to 25% in terms of the solid content weight ratio. Even if it exceeds 25% or less than 2%, the antifogging maintenance property is not sufficient. On the other hand, if it exceeds 25%, the antifogging agent liquid stability may be lowered.

  Further, the antifogging liquid composition of the present invention may contain additives such as a silane coupling agent, a surfactant and an antibacterial agent in order to improve adhesion, coating properties, stain resistance, etc. In particular, the inclusion of a surfactant such as sodium dialkylsulfosuccinate is preferable from the viewpoint of ensuring good coatability. The addition amount of the surfactant is preferably 0.5 to 20% by weight in the solid content of the antifogging liquid composition.

  As a method for applying the antifogging liquid composition to the surface of the glass substrate, known methods such as dipping, brushing, roll coating, curtain flow coating, and spraying can be used.

The coating amount of the antifogging liquid composition is 5 to 200 mg / m ² , preferably 10 to 150 mg / m ² as a dry film amount.
a m ^2. When it exceeds 200 mg / m ² , the transparency of the coating is lowered. When it is less than 5 mg / m ² , the antifogging maintenance property is not sufficient.

Polyvinyl alcohol or polycarboxylic acid, which is a water-soluble resin in the antifogging liquid composition applied to the surface of the glass substrate, is crosslinked by heating, and the hydroxyl group or carboxyl group is crosslinked with a zirconium-based crosslinking agent and cured to form an amorphous metal. The antifogging film of the present invention which is a poorly water-soluble film containing an oxide is formed.
The heating temperature is preferably 100 to 200 ° C., and the heating time is preferably 5 seconds to 30 minutes. When the heating temperature is less than 100 ° C. and the heating time is less than 5 seconds, the curing is insufficient and the antifogging maintenance property is not sufficient. Even when the heating temperature is 200 ° C. and the heating time exceeds 30 minutes, the antifogging maintenance property is not further improved, which is economically disadvantageous. Because of these heating conditions, a normal hot air oven can be used.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “part” means “part by mass” unless otherwise specified.
[Production Example 1]
Polyacrylic acid aqueous solution (number average molecular weight 20000, acid value 779, solid content 5%) 40 parts, 25% ammonia water 1.9 parts, sodium dialkylsulfosuccinate aqueous solution (“Neocol SW-C manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) ”; Active ingredient 70%) 0.85 part and 58 parts of deionized water are uniformly mixed to obtain a raw material liquid A.
[Production Example 2]
Polycarboxylic acid aqueous solution (copolymer of acrylic acid and methyl methacrylate, number average molecular weight 15000, acid value 700, solid content 5%) 40 parts, 25% aqueous ammonia 1.7 parts, dialkylsulfosuccinate sodium aqueous solution “Neocol SW-C” manufactured by Ichi Kogyo Seiyaku Co., Ltd .; active ingredient 70%) 0.85 part and 58 parts of deionized water are uniformly mixed to prepare raw material liquid B
[Production Example 3]
30 parts of polyvinyl alcohol (number average molecular weight 20000, saponification degree 98%) is uniformly dissolved in 580 parts of deionized water at 90 ° C., cooled to room temperature, and then a sodium dialkylsulfosuccinate aqueous solution (“Daiichi Kogyo Seiyaku Co., Ltd.” Neocor SW-C "; active ingredient 70%) 8.5 parts are added to make a raw material liquid C.
[Production Example 4]
30 parts of polyethylene glycol (number average molecular weight 10,000) is uniformly dissolved in 580 parts of deionized water at 90 ° C., cooled to room temperature, and then an aqueous sodium dialkylsulfosuccinate (“Neocol SW-C” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Active ingredient 70%) 8.5 parts is added to prepare raw material liquid D.
[Production Example 5]
60 parts of water glass (“2K potassium silicate” manufactured by Nippon Chemical Industry Co., Ltd .; solid content 30%) and 40 parts of deionized water are uniformly mixed to obtain a raw material liquid E.
[Production Example 6]
50 parts of ammonium zirconium carbonate ("Zircosol AC-7" manufactured by Daiichi Rare Element Chemical Co., Ltd .; solid content 28%) and 50 parts of deionized water are uniformly mixed to prepare a raw material liquid F.
[Production Example 7]
A sodium dialkylsulfosuccinate aqueous solution (“Neocol SW-C” manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; 70% active ingredient) and 57.7 parts of deionized water are uniformly mixed to prepare a raw material liquid G.

[Example 1]
Liquid composition comprising 30 parts of raw material liquid A, 10 parts of colloidal silica water dispersion (“Snowtex N” manufactured by Nissan Chemical Co .; solid content 20%), 2 parts of raw material liquid, 58 parts of raw material liquid G, and 300 parts of deionized water. A clean 1.5 mm thick soda glass was immersed in the glass. This was immediately put into a hot air oven at 150 ° C. for 5 minutes and dried to obtain a test plate. The dry film amount on one side was 30 mg / m ² . Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated by the following methods. The results are shown in Table 3.

Transparency :
Visually compare transparency with uncoated glass (mirror).
○: Transparency good △: Slightly opaque ×: Slightly opaque
Anti-fog maintenance :
The test plate was immersed in tap water at 25 ° C. for 20 seconds, then subjected to natural drying for 5 minutes at 25 ° C. and 60% relative humidity as one cycle, and then immersed in tap water at 25 ° C. for immediate treatment. The degree of fogging of the glass is evaluated by standing on 85 ° C. hot water at an angle of 60 °.
○: Cloudy area less than 10% Δ: Cloudy area 10-20% ×: Cloudy area 20% or more
Rinse resistance :
The test plate was immersed in an aqueous solution of hair rinse (super mild conditioning rinse; manufactured by FT Shiseido Co., Ltd.) at a concentration of 1 × 10 ⁻⁵ % at 25 ° C. for 5 seconds, naturally dried at 25 ° C. and 60% relative humidity for 10 minutes, and then 25 ° C. Rinse with a 0.1% aqueous neutral detergent solution followed by tap water. This is defined as one cycle, and immediately after performing a predetermined cycle, the degree of fogging of the glass is evaluated by standing on the hot water at 85 ° C. at an angle of 60 ° with the processing surface down.
○: Cloudy area less than 10% Δ: Cloudy area 10-20% ×: Cloudy area 20% or more
Abrasion resistance :
Slide with a sponge and visually check the appearance.
○: No abnormality at all △: There is a shallow flaw ×: There is a deep flaw reaching the substrate

[Examples 2 to 7]
Using the raw material liquid A, the raw material liquid D, the raw material liquid E, and the raw material liquid F, liquid compositions as shown in Table 1 were obtained. These liquid compositions were applied to a clean mirror surface having a thickness of 5 mm by a bar coater so as to have a dry coating amount of 100 mg / m ² .
This was immediately placed in a hot air oven at 150 ° C. for 3 minutes to dry. Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated. The results are shown in Table 3.
Example 8
A clean 1.5 mm thick soda glass was immersed in a liquid composition comprising 30 parts of the raw material liquid B, 20 parts of the raw material liquid E, 2 parts of the raw material liquid F, 58 parts of the raw material liquid G, and 300 parts of deionized water. This was immediately put into a hot air oven at 150 ° C. for 5 minutes and dried to obtain a test plate. The dry film amount on one side was 30 mg / m ² . Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated by the following methods. The results are shown in Table 3.
Example 9
A liquid composition comprising 40 parts of raw material liquid C, 20 parts of raw material liquid E2, 2 parts of raw material liquid, 58 parts of raw material liquid G, and 300 parts of deionized water is applied to a clean 5 mm thick mirror surface with a dry coating amount of 80 mg / m ² . It was applied with a bar coater. This was immediately placed in a hot air oven at 150 ° C. for 3 minutes to dry. Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated. The results are shown in Table 3.

[Comparative Example 1] (No antifogging treatment)
The anti-fogging maintenance property, rinse resistance, and abrasion resistance of a clean 5 mm thick mirror not coated with the antifogging liquid composition were evaluated. The results are shown in Table 3.
[Comparative Examples 2 to 4] (Liquid composition lacking one component among water-soluble resin, amorphous metal oxide, and zirconium-based crosslinking agent)
Using the raw material liquid A, the raw material liquid E, the raw material liquid F, and the raw material liquid G, a liquid composition having the composition shown in Table 2 is applied to a clean 5 mm thick mirror surface with a dry coating amount of 100 mg / m ² . It was applied with a bar coater. Immediately 1
It put into a 50 degreeC hot-air oven for 180 second, and was heat-dried. Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated. The results are shown in Table 3.
[Comparative Example 5] (Polyethylene glycol used as water-soluble resin)
A liquid composition comprising 30 parts of the raw material liquid D, 20 parts of the raw material liquid E, 2 parts of the raw material liquid F, 58 parts of the raw material liquid G, and 300 parts of deionized water becomes a dry coating amount of 80 mg / m ² on the surface of a clean 5 mm thick mirror. It was applied with a bar coater. This was immediately placed in a hot air oven at 150 ° C. for 3 minutes to dry. Antifogging maintenance property, rinse resistance, and abrasion resistance were evaluated. The results are shown in Table 3.

  As can be seen from the results in Table 3, the performances of the glass surface-generated coatings of Examples 1 to 9 are extremely good in all of anti-fogging maintenance property, rinse resistance and wear resistance, whereas Comparative Example 2 A glass surface generation coating using a liquid composition that lacks one component of water-soluble resin, amorphous metal oxide, and zirconium-based cross-linking agent, or the water-soluble resin is outside the scope of the present invention. All of the anti-fogging maintenance property, the rinse resistance and the wear resistance were insufficient.

As described above, the antifogging glass of the present invention can form an antifogging film excellent in antifogging maintenance property, rinse resistance, abrasion resistance, etc. on the glass surface, and the film forming method is also simple. Therefore, it should be widely and suitably applied to glass surfaces that require excellent anti-fogging properties, such as automobile windows, bathroom mirrors, endoscope lenses, dental mirrors, and instrument panel cover glasses. Can do.

Claims (4)

  Antifogging liquid containing at least one water-soluble resin selected from the group consisting of polyvinyl alcohol, polycarboxylic acid having an acid value of 600 to 950, an amorphous metal oxide, and a zirconium-based crosslinking agent on the surface of the glass substrate. An antifogging glass having an antifogging film formed by applying and heating the composition.   The anti-fogging solution according to claim 1, wherein the solid content of the antifogging liquid composition comprises 5 to 70% by weight of a water-soluble resin, 25 to 80% by weight of an amorphous metal oxide, and 2 to 25% by weight of a zirconium-based crosslinking agent. Frosted glass.   The antifogging glass according to claim 1 or 2, wherein the glass substrate is a mirror provided with a reflective layer on the back side where no antifogging film is formed. Antifogging liquid containing at least one water-soluble resin selected from the group consisting of polyvinyl alcohol, polycarboxylic acid having an acid value of 600 to 950, an amorphous metal oxide, and a zirconium-based crosslinking agent on the surface of the glass substrate. A method for producing an antifogging glass, comprising: a step of applying a composition to form a coating layer; and a step of heating and drying the coating layer to form a film.