JPH09221607A - Hydrophilic article and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hydrophilic article having a hydrophilic film with excellent durability and high hardness and useful as glass for building, etc., by coating a surface of an article with a specific surface-treating liquid and baking the coating layer. SOLUTION: A surface of an article is coated with a surface-treating agent composed of (A) phosphoric acid and/or its salt, (B) a soluble aluminum compound, (C) a water-soluble silicate, (D) a nonionic surfactant and (E) a solvent and the coated article is heat-treated at 300-700 deg.C. Preferably, the component A is a phosphoric acid sodium salt, potassium salt, etc., the component B is aluminum nitrate, aluminum chloride, etc., the component C is lithium silicate, the component D is a polyoxyethylene sorbitan fatty acid monoester and the article is a plate glass or a metal plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article having a hydrophilic surface and a method for producing the same, and more particularly, to a surface of glass, metal, plastics or the like, which has high hardness and is excellent in durability and durability. The present invention relates to a coated article and a manufacturing method thereof.

[0002]

2. Description of the Related Art By imparting hydrophilicity to the surface of an article, it is possible to improve the affinity between water and polar substances and the article, and to make contact, adhesion, adhesion, etc. that were originally difficult. Therefore, it is expected to develop into new application fields such as adhesion of hydrophilic substances to the surface of articles and surface reaction in an aqueous solution system.

On the other hand, it has been conventionally practiced to prevent fogging, dew condensation, and stains by making the surface of a transparent article hydrophilic. The method of imparting hydrophilicity includes a method of physically or chemically treating the surface to change the molecular structure of the surface to form hydrophilic groups, a method of changing the microscopic shape of the surface, and a method of imparting hydrophilicity to the surface. A method of forming a coating having the same is known.

As a physical method, a hydrophilic treatment such as plasma treatment or laser irradiation treatment has been put into practical use, but it is generally said that there is a problem in sustainability although it is effective in a short period after the treatment. Chemical methods include a method of generating radicals on the surface and graft-polymerizing a polymerizable compound having a hydrophilic residue, a method of breaking the bond on the surface with an acid or a basic substance, and changing the surface to a hydrophilic residue. And so on.

As the hydrophilic film, a polymer film having a hydrophilic chemical bond or residue in its molecular chain or side chain has been widely studied. Among them, polyvinyl alcohol (PVA) which exhibits hydrophilicity by a hydroxyl group. Membranes have been put to practical use in a wide range of applications because of their excellent hydrophilicity and economical reasons.

Further, it is generally known that a water-soluble inorganic substance or an inorganic polymer has a hydrophilic coating.

[0007]

However, the hydrophilicity due to the above-mentioned physical treatment can maintain its effect only in the short term, and the organic polymer film generally has insufficient water resistance and durability. In addition, the hardness of the film is relatively low, which is not practically sufficient depending on the application.

A coating film made of an inorganic substance has a relatively high hardness, but a substance exhibiting hydrophilicity has a high solubility in water, and therefore the coating film easily disappears, so that its practical use is limited.

[0009] Therefore, an object of the present invention is to provide an article having a hydrophilic film having excellent durability, which is preferably highly transparent.

[0010]

The inventors of the present invention have made earnest studies to solve the above-mentioned problems, and found that the surface of an article is coated with a surface treatment liquid consisting of specific components and baked to obtain durability. It was found that a hydrophilic film having excellent hardness and high hardness can be formed, and has reached the present invention.

That is, according to the present invention, the surface of an article is coated with a surface treatment agent comprising phosphoric acid or a salt thereof, a soluble aluminum compound, a water-soluble silicate, a surfactant and a solvent, and then at 300 to 700 ° C. An article having a hydrophilic surface characterized by being heat treated and a method for producing the same.

Hereinafter, the present invention will be described in detail. Phosphoric acid according to the present invention, anhydrous phosphoric acid, metaphosphoric acid, pyrophosphoric acid,
Orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, halogenophosphoric acid (halogen is chlorine or fluorine), and the like. Further, instead of these phosphoric acids or part thereof, a phosphoric acid derivative soluble in a solvent may be used, and various condensed phosphates, partially substituted with halogen (chlorine or fluorine) or an organic group may be used. It can also be a salt of phosphoric acid or a phosphoric acid ester. These salts of phosphoric acid include sodium salts, potassium salts, ammonium salts and the like, and the phosphoric acid esters include the above-mentioned methyl ester, ethyl ester, isopropyl ester and butyl ester of phosphoric acid. Typical examples of these phosphoric acid derivatives are sodium orthophosphate, sodium triphosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid. Various phosphoric acid derivatives such as calcium dihydrogen, ammonium hydrogen phosphate, potassium hydrogen phosphate, ethyl phosphate, triethyl phosphate, and tributyl phosphate are included, but are not limited thereto.

The water-soluble aluminum compound according to the present invention includes aluminum salts such as aluminum nitrate, aluminum chloride and aluminum sulfate, hydrous salts thereof or aluminum isopropoxide, aluminum triethoxide, monosec-butoxyaluminum diisopropylate and the like. Aluminum alkoxide, aluminum chelate, aluminum acylate (O = Al
-OOCR: R represents an alkyl group) and the like. Among these, aluminum nitrate nonahydrate is particularly preferred because it is easily decomposed by heat.

The water-soluble silicate according to the present invention is a lithium, sodium or potassium salt of silicic acid. These form salts of various forms such as orthosilicate and metasilicate. For example, in the case of lithium silicate, lithium orthosilicate,
For sodium silicate such as lithium metasilicate and hexalithium orthodisilicate, mention should be made of sodium metasilicate, sodium orthosilicate, sodium disilicate, sodium tetrasilicate, etc., potassium metasilicate, potassium tetrasilicate, etc. or various hydrates thereof. You can Further, these silicates are industrially available in the form of an aqueous solution, but they can also be used. Among various silicates, lithium silicate or its hydrate is particularly preferably used.

The surfactant according to the present invention is a nonionic surfactant. Examples of such nonionic surfactants include alkyl ether type having a polyoxyethylene unit as a cumulative atomic group, ether type such as alkylallyl ether type, alkyl ester type, ester type such as sorbitan monoalkyl ester type, and polyoxyethylene. Examples include condensation types with amines such as alkylamines, condensation types with amides such as polyoxyetherene alkyl amides, condensation types with polyoxypropylenes such as polyoxyethylene polyoxypropylene, and polyethyleneimine-based compounds. be able to.

Further, as those having no cumulative atomic group, ester type such as sorbitan alkyl ester, other polyhydric alcohol and fatty acid ester such as various glycerin monofatty acid ester, pentaerythritol ester and saccharose ester, fatty acid Examples thereof include amide type such as ethanolamide, methylolamide, oxymethylethanolamide, and fatty acid ethanolamide derivative, higher alcohols, glucosides, higher alkyl ethers and the like.

In the present invention, the HLB value is preferably 9 or more, more preferably 11 or more. Alternatively, the polyhydric alcohol is an ester type derived from sorbitan, and among them, the monoester type is preferable. Further, ester type nonionic surfactants having a polyoxyethylene cumulative atomic group are preferable. The fatty acid forming the ester is a straight chain saturated fatty acid having 12 to 18 carbon atoms, and particularly preferably lauric acid, palmitic acid, stearic acid or oleic acid. Also, the cumulative number of polyoxyethylene is 5 to 50 in terms of the average number.
The thing of about 15 to 30 is preferable, and that of about 15 to 30 is more preferable.

Particularly preferred commercially available surfactants are Tween (Tween: Imperial Chemical Product) -20, -21, -40, -60, -61, -6.
5, -80, -81, -85, Leodol TW (Kao product) -L120, -L106, -P120, -S12
0, -S106, -O120, -O106, -L12
0, Leo Doll Super TW (Kao product) -L120,
Examples include -S120, -O120, and the same or similar as those commercially available from each company. Of these, particularly preferred are Tween-20,-
40, -60, -80, Leodol TW-L120,-
Examples thereof include P120, -S120, -O120, and the like, or their equivalents or similar products. These are about 2
They are polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate and polyoxyethylene sorbitan monooleate having 0 polyoxyethylene atomic group.

The surface treating agent according to the present invention uses a solvent composed of water and / or a water-soluble organic solvent as the solvent. Phosphoric acid or a salt thereof, a soluble aluminum compound, and a water-soluble silicate may be sequentially mixed, or may be added to a solvent at the same time to be prepared at one time. It is also possible to add the other to the prepared solution, and to prepare water and / or
Alternatively, they can be prepared by dissolving them in a water-soluble organic solvent and mixing them. The water-soluble organic solvent is not particularly limited, but as alcohols, lower alcohols,
Polar solvents such as alkoxy alcohols and polyhydric alcohols are preferable, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, glycerin and the like can be mentioned, and other acetone And so on. Further, two or more of these may be mixed and used. The selection of the solvent is determined by the boiling point, the solubility, the storage stability, the coating conditions, the manufacturing cost, etc., but from the viewpoint of workability and easiness of handling, the most preferable solvent is a mixed solvent of ethanol and water. . The mixing ratio of water and alcohol depends on the type of aluminum compound and silicate used and the concentration of the surface treatment agent.
Water is preferably about 0.1 to 10 (volume ratio).

A solution having the composition before or after the addition of the surfactant component from the surface treatment liquid according to the present invention (hereinafter referred to as "P
ALS liquid ". ), The concentration of the phosphoric acid or the aluminum compound is 0.1% in terms of P ₂ O ₅ or Al ₂ O ₃ .
It is 02 to 1 mol / l, and more preferably 0.05 to 0.5 mol / l. If the concentration of any of them is less than 0.02 mol / l, a coating having a sufficient film thickness cannot be formed by one coating, which is not preferable because the operation becomes complicated.
When the concentration is more than 1, it is difficult to form a smooth, uniform and transparent film, which is not preferable. In these solutions, P ₂ O ₅ or Al ₂ O ₃ conversion display, Al ₂ O ₃
The molar ratio of / P ₂ O ₅ is 2/8 to 8/2 and is 4/6 to 6
It is preferably / 4. When the molar ratio is less than 2/8 or more than 8/2, depending on the conditions of coating or heat treatment,
It may devitrify, which is not preferable.

The concentration of the water-soluble silicate in the PALS solution is preferably 0.05 to 1 mol / l in terms of SiO ₂ , and more preferably 0.1 to 0.6 mol / l. Silicate concentration is 0.05 mol / l in terms of SiO _2.
If it is less than the above range, it is difficult to obtain a stable film having a sufficient thickness to exhibit hydrophilicity. Further, if the concentration exceeds 1 mol / l, the prepared surface treatment agent becomes unstable and gelation is likely to occur, which is not preferable.

The surfactant according to the present invention is added in an amount of 0.1 to 200 parts by weight, preferably 1 to 100 parts by weight, based on 100 parts by weight of the PALS solution. When 0.1 part by weight is obtained, the hydrophilicity is almost the same as that of the film formed only from the PALS solution, and when it exceeds 200 parts by weight, the stability of the surface treatment solution is deteriorated, which is not preferable.

The surface treatment liquid may be prepared by adding a predetermined amount of the surfactant as it is or in a state of being dissolved in a solvent to the PALS liquid prepared by the above-mentioned method. As the surface treatment agent according to the present invention, as generally known in coating film formation, additives commonly used for the purpose of adjusting film forming conditions such as a thickener and a leveling agent can be applied.

In the method of the present invention, the surface treatment agent is applied to the surface of the article and then heat-treated, but the number of times of application and heat treatment may be two or more. Embodiments of the present invention include forming a coating by any procedure such as performing heat treatment at once after repeating application only a plurality of times and performing a series of operations of coating and heat treatment a plurality of times.

In the method of the present invention, the method for applying the surface treating agent to the surface of the article may be appropriately selected from known methods, and includes spin coating, dipping, roll coater, brush coating, spraying and the like. But not limited thereto. Since the surface treatment agent applied to the surface of the article may lack stability over a long period of time by simply volatilizing the solvent and drying, it is preferable to perform heat treatment. Although the reason for the improvement in stability by heat treatment is not clear, it is presumed that the formation of a three-dimensional crosslinked structure of phosphoaluminosilicate, which greatly contributes to water resistance, is promoted.

The heat treatment temperature in the present invention varies depending on the heat treatment time and is not uniquely determined, but is usually 300.
-700 degreeC is preferable and 400-600 degreeC is more preferable. If the temperature is lower than 300 ° C, the hydrophilicity of the formed film is low, and the water resistance is low, which may be a problem in practical use. It is not preferable because it causes deformation of the substrate such as, and chemical changes.

In the article of the present invention, the film thickness is from 10 nm to
100 μm, preferably 50 nm to 10 μm, 1
It is more preferably from 00 nm to 5 μm. When the film thickness is less than 10 nm, the durability of the film is lowered and the hydrophilicity cannot be maintained for a long time, and when it exceeds 100 μm, devitrification or poor smoothness is unfavorable.

The article according to the present invention is not particularly limited as long as it is made of a material resistant to heat treatment, and may have any shape. Applicable materials include
Metals such as iron, stainless steel, and aluminum, plastics such as polyether resin, polysulfone resin, and polyimide resin, ceramics such as alumina, titania, quartz, fused silica, silicon nitride, silicon carbide, soda lime glass, borosilicate glass, Glasses such as various optical glasses can be exemplified, but transparent ceramics or glasses are most effective.

In the article of the present invention, the material may be previously coated with another material, but since it is necessary to impart hydrophilicity to the surface, the outermost layer of any article is used. It is preferable to form the coating film according to the present invention.

Specific examples of the hydrophilic article of the present invention include ordinary glass plates, automobile glasses, aircraft glasses, greenhouse glasses, mirrors, water glasses, cameras, spectacle lenses, and one or more layers on the surface. Low-reflection glass plate with a film of different refractive index formed on it, glass plate with conductivity on the surface, functionalized glass plate with metal oxide, metal nitride, metal silicide or metal coated on the surface, humidity sensor , A heat exchanger fin, and the like, but are not limited thereto.

In the following, further details will be described based on embodiments.

[0032]

EXAMPLES The following [Evaluation test of antifogging property] was carried out on a glass plate provided with hydrophilicity. Water is poured into a container equipped with a heating device and provided with an opening having a diameter of 5 cm at the upper end, and the water is heated to fill the space of the container with saturated steam at 43 ° C.
While blowing air at 25 ° C. from the back surface of the glass plate, the film having the hydrophilic film formed thereon is placed horizontally in the opening with the film surface facing downward. It is kept in contact with water vapor for 3 minutes and the degree of fogging is visually observed.

If it was confirmed in this evaluation test that a water film was formed and no fogging occurred, the glass test piece was dried with hot air at 80 ° C., then cooled to 25 ° C., and again subjected to [Evaluation test for anti-fogging property. ] Is carried out and evaluated.

A After 10 times [evaluation test of antifogging property], water film formation B In 6 to 9 times [evaluation test of antifogging property] water droplet formation or clouding C 2 to 5 times [of antifogging property] Water drop formation or clouding in the evaluation test] D Water drop formation or clouding in one evaluation test of antifogging property [Example 1] Reagent grade phosphoric acid 0.02 mol, reagent grade aluminum nitrate 9-hydrate. After taking 02 mol in a 200 ml beaker and adding 20 g of pure water to form a uniform aqueous solution, lithium silicate (Nissan Chemical Co., Ltd. LS) is added so that the SiO ₂ component conversion becomes 0.02 mol while stirring. -3
5) was gradually added. Further, ethyl alcohol was added to make the total liquid volume 100 ml.

To 100 ml of the obtained liquid was added 2 g of Leodol TW-L120 (Kao product: polyoxyethylene sorbitan monolaurate having about 20 polyoxyethylene atomic groups), and the mixture was stirred to prepare a uniform solution. .
This solution was spin-coated (400 rpm) on a 10 cm square commercial soda lime glass (plate thickness 2 mm) as a hydrophilic surface treatment agent solution, and then the glass plate was pre-dried in a dryer at 70 ° C. for 20 minutes, 3 at a temperature of 500 ° C
Heat treatment was performed for 0 minutes. The results of hydrophilicity evaluation of the obtained surface-treated glass plate with a goniometer-type contact angle measuring device are shown in Table 1. The contact angle of water drops on this glass plate is 0
The appearance of the film was smooth and colorless and good.

[Evaluation test for antifogging property] was carried out on this glass plate. The results are shown in Table 1.

[0037]

[Table 1]

Example 2 A PALS solution was prepared in the same manner as in Example 1, and 5 g of Rheidol TW-L120 was added to 100 ml of the resulting solution, followed by stirring to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 3 A PALS solution was prepared in the same manner as in Example 1, and 100 g of the resulting solution was added with 100 g of Leodol TW-L120 and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 4 A PALS solution shown in Table 1 was prepared in the same manner as in Example 1 with 0.024 mol of phosphoric acid and 0.016 mol of aluminum nitrate nonahydrate, and 20 g per 100 ml of the resulting solution.
Rheodor TW-L120 was added and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 5 The same operation as in Example 1 except that 0.02 mol of phosphorus pentoxide was used in place of phosphoric acid, and a mixed solvent of ethanol / water in a volume ratio of 1/1 was used in place of pure water. The PALS shown in Table 1
A liquid was prepared, 10 g of Rheodor TW-L120 was added to 100 ml of the obtained liquid, and the mixture was stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 6 Aluminum chloride 6 instead of aluminum nitrate 9-hydrate
A PALS solution shown in Table 1 was prepared in the same manner as in Example 1 using 0.02 mol of a water salt, and 20 g of Leodol TW-L120 was added to 100 ml of the resulting solution, followed by stirring to form a uniform solution. Prepared. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 7 The same procedure as in Example 1 was carried out except that 0.02 mol of aluminum sulfate was used instead of aluminum nitrate nonahydrate and a mixed solvent of ethanol / water in a volume ratio of 4/6 was used instead of ethanol. A PALS solution shown in Table 1 was prepared by an operation, and 10 g of Leodol TW-L120 was added to 100 ml of the obtained solution and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 8 A PALS solution shown in Table 1 was prepared in the same manner as in Example 1 except that isopropanol was used instead of ethanol, and 20 g of Reodol TW-L12 was added to 100 ml of the obtained solution.
0 was added and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 9 A PALS solution shown in Table 1 was prepared in the same manner as in Example 1 except that acetone was used in place of ethanol, and 20 g of Leodol TW-L120 was added to 100 ml of the resulting solution and stirred. To prepare a homogeneous solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 10 A PALS solution shown in Table 1 was prepared in the same manner as in Example 1 except that 0.02 mol of sodium silicate was used instead of lithium silicate, and 40 g of Reodol TW was added to 100 ml of the obtained solution.
-L120 was added and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 11 A PALS solution was prepared in the same manner as in Example 1, and 100 g of the resulting solution was added with 10 g of Leodol TW-O120 (Kao product: polyoxyethylene having about 20 polyoxyethylene atomic groups). Sorbitan monooleate) was added and stirred to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like.

Example 12 A PALS solution was prepared in the same manner as in Example 1, and 20 g of Rheidol TW-O120 was added to 100 ml of the resulting solution, followed by stirring to prepare a uniform solution. Using this solution as a hydrophilic surface treating agent chemical solution, film formation and water droplet contact angle measurement were carried out. Table 1 shows film forming conditions, evaluation results, and the like. The appearance of the films formed in Examples 2 to 12 was smooth and colorless and transparent.

Comparative Example 1 A PALS solution was prepared in the same manner as in Example 1, a surfactant was not added, and the solution was used as a hydrophilic surface treating agent solution to form a film and measure the contact angle of water droplets. . Table 1 shows film forming conditions, evaluation results, and the like.

Comparative Example 2 3 g of Rheodor TW-L120 was dissolved in 100 ml of ethanol, and the same procedures as in Example 1 were carried out to form a coating film shown in Table 1 and to measure a water drop contact angle. In addition, in the [Evaluation test of antifogging property], water droplets were generated at the first time. Table 1 shows film forming conditions, evaluation results, and the like.

[0051]

The hydrophilic article of the present invention has transparency and can maintain the hydrophilicity for a long period of time.
It has a remarkable effect that it is suitable for construction glass, optical glass products, glass for automobiles, etc., which require pollution prevention and visibility maintenance, and also for heat radiation fins for heat exchangers.

Claims (12)

[Claims] 1. A surface treatment agent comprising an aluminum compound soluble in phosphoric acid and / or its salt, a water-soluble silicate, a nonionic surfactant and a solvent is applied to the surface of an article,
An article having a hydrophilic surface, which is then heat-treated at 300 to 700 ° C. 2. The hydrophilic article according to claim 1, wherein the salt of phosphoric acid is one or more phosphates selected from sodium, potassium and ammonia salts of phosphoric acid. 3. The hydrophilic compound according to claim 1, wherein the soluble aluminum compound is one or more aluminum compounds selected from aluminum nitrate, aluminum chloride, aluminum sulfate or hydrates thereof. Goods. 4. The hydrophilic article according to claim 1, wherein the water-soluble silicate is one or more silicates selected from lithium, sodium and potassium salts of silicic acid. 5. The hydrophilic article according to claim 1, wherein the water-soluble silicate is lithium silicate. 6. The hydrophilic article according to claim 1, wherein the nonionic surfactant is a polyoxyethylene sorbitan fatty acid monoester. 7. The hydrophilic article according to claim 6, wherein the fatty acid of polyoxyethylene sorbitan fatty acid monoester is lauric acid, palmitic acid, stearic acid or oleic acid. 8. The hydrophilic article according to claim 1, wherein the solvent is water and / or a water-soluble organic solvent. 9. The hydrophilic article according to claim 1, wherein the solvent is a mixed solvent of water and ethanol. 10. The hydrophilic article according to claim 1, wherein the article is a plate glass or a metal plate. 11. The hydrophilic article according to claim 1, wherein the article is a plate glass having no coating other than the coating imparting hydrophilicity or having one or more coatings. 12. A surface treating agent comprising phosphoric acid or its sodium, potassium and ammonium salts, a soluble aluminum compound, a water-soluble silicate and a solvent is applied to the surface of an article and then heat treated at 300 to 700 ° C. A method for producing an article having a hydrophilic surface, comprising: