JP2000319543A - Hydrophilic member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a preventive hydrophilic member less apt to become cloudy, and be attached with water droplets and a soil while keeping a sufficient membrane hardness and a high endurance. SOLUTION: This hydrophilic member comprises a base material and a hydrophilic membrane containing at least a hydrophilic inorganic amorphous martial and hydrophilic metal oxide particles, and has a property that in a state of attaching water on the hydrophilic membrane and keeping the hydrophilic membrane perpendicularly for removing excess water, the weight of water membrane attached to the hydrophilic membrane is 0.23-0.50 g per 10 cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hydrophilic material whose surface is required to have a hydrophilic property, specifically, an antifogging property and an antifouling property, for example, a glass, a mirror, a reflecting plate, a protective plate and the like. The present invention relates to a sex member.

[0002]

2. Description of the Related Art Transparent members such as glass and plastic,
Reflection members such as mirrors and metal plates, and members such as members having a design on the surface, when the surface temperature falls below the dew point temperature, moisture in the air is likely to agglomerate on the surface and cause fogging. Further, when rainwater or splashes adhere to the surfaces of these members and water droplets adhere to the surfaces, they easily adhere as water droplets.

[0003] When fogging or water droplets adhere to the surface in this way, there is a problem that the original function of the member cannot be exhibited. Further, there is a problem that the visibility and design of the member are reduced due to light scattering.

[0004] In order to solve the above-mentioned problems of fogging and light scattering, a method of making the surface hydrophilic has been proposed.

In Japanese Patent Application Laid-Open No. 9-278431, a surface treatment material comprising phosphoric acid or a salt thereof, a soluble aluminum compound, a water-soluble silicate, a surfactant and a solvent is applied to the surface of a base material. A method for forming irregularities on the surface by heat treatment at a temperature of ° C. is disclosed.

[0006] It is generally known that when the actual surface area of the surface is increased by forming irregularities on the surface, the contact angle of the attached water droplet is reduced.

[0007] Japanese Patent Application Laid-Open No. H11-100234 discloses that
A film made of metal oxide particles and a metal oxide having a particle diameter of 0 nm is formed, and the arithmetic average roughness (Ra) is 1.5 to 80.
There is disclosed a method for forming unevenness having an average unevenness interval (Sm) of 4 to 300 nm in nm.

On the other hand, in order to exhibit the anti-fogging property due to the adhesion of water vapor, the contact angle of water needs to be as small as about 10 degrees or less. From these facts, it is necessary to increase the surface roughness in order to form irregularities on the surface and exhibit anti-fog properties, but if the roughness is increased, transparency will be lost, film hardness and durability Degradation of membrane due to reduced
It is considered that the function is deteriorated due to clogging due to adhesion of dirt.

On the other hand, in building materials such as outer walls, the problem that dust and the like floating in the air flow down on the wall surfaces with rainwater and appear as black stains, particularly in urban areas and industrial areas. In recent years, it has been considered that it is desirable to make the surface as hydrophilic as possible for urban dust containing a large amount of hydrophobic components (Polymer, Vol. 44, May 1995, p. 307). However, what is generally called a hydrophilic paint has a static contact angle of water of 50 degrees or more and a hydrophilic graft polymer of 30 to 40 degrees, which is considered to be unable to prevent adhesion of urban dust.

[0010]

As described above, there are proposals for preventing the clouding and scattering of light by making the member hydrophilic, and for preventing the adhesion of dirt. However, in order to sufficiently exhibit the hydrophilicity. However, there is a problem that the unevenness needs to be increased, the transparency is lost, the film hardness and durability are reduced, and the function is reduced due to dirt. Therefore, an object of the present invention is to obtain a transparent hydrophilic film having excellent antifogging property and high durability without lowering the film hardness in order to solve the above problem.

[0011]

SUMMARY OF THE INVENTION In the present invention, there has been invented a member in which water adhering to a hydrophilic film exhibits an antifogging property by forming and holding a water film. Specifically, when steam or splashes adhere to a mirror or the like disposed in the bathroom, the film formed on the surface continues to retain the adhered water, and a water film is formed by the water that adheres one after another to be uniform. . In this state, even when the surface temperature is below the dew point temperature and water vapor touches the surface, or when water droplets adhere to the surface due to splashing, the water film continues to be maintained, so that light is not scattered and is linear. And the visibility does not decrease. In the case of excessive adhesion, water flows down, but the hydrophilic coating in the present invention keeps water in a certain range, so that the antifogging effect can be maintained.

In the case of building materials such as outer walls, dust and the like floating in the atmosphere flow down the wall surfaces with rainwater and become black stains. However, the hydrophilic member according to the present invention forms a water film on the surface. Therefore, no dirt adheres. That is, the dirt is attached because when the dirt substance flows down in the rain, the adhesive action out of the adhesive action on the member surface and the removing action by running water is superior. If the water film is formed in advance, it becomes difficult for the dirt substance to directly contact the surface of the member, so that an antifouling effect can be exhibited.

[0013] As an embodiment of the hydrophilic member for exhibiting the above-described effects, the hydrophilic member comprises at least a hydrophilic inorganic amorphous substance and hydrophilic metal oxide particles formed on the substrate. Weight of the water film adhered to the hydrophilic film in a state where water is adhered to the hydrophilic film and excess water is removed by holding the hydrophilic film vertically to remove the excess water. Is 0.23 g to 0.5 per 10 cm ²
0 g of a hydrophilic member is provided. (Method of measuring water film)
Specifically, first, in an environment where the room temperature is set at 15 ° C. or more and 25 ° C. or less and the relative humidity is 30% or more and 80% or less, a hydrophilic member previously stabilized for 1 hour or more in the environment is weighed. The mass is measured at, and this is defined as X (g). After the measurement, the member is placed so that the hydrophilic surface of the member is substantially vertical, and only the hydrophilic film is wetted with water having a water temperature substantially equal to room temperature of 15 ° C or higher and 25 ° C or lower. Make sure it is formed. After a lapse of 15 seconds, the water accumulated at the lower portion is removed, and the total weight is measured with a balance. This is defined as Y (g). Assuming that the area of the hydrophilic surface of the used member is Z (cm ² ), the amount of water per 10 cm ² is (X
−Y) × 10 / Z (g).

The amount of water thus measured is 10 cm
A hydrophilic member capable of forming a water film of 0.23 g or more and 0.5 g or less per ² is provided, but by setting the water retention of the hydrophilic coating to 0.23 g / 10 cm ² or more, A uniform and sufficient water film can be formed on the surface, and by controlling the water film to 0.5 g / 10 cm ² or less, the water film can be homogenized. At this time, 0.2 per 10 cm ²
It is a more preferable embodiment that a water film can be formed with 3 g or more and 0.35 g or less of water.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (Hydrophilic film) The hydrophilic film in the present invention comprises at least a hydrophilic inorganic amorphous substance and hydrophilic metal oxide particles. In order to stably exhibit the hydrophilicity required for forming a water film, that is, the hydrophilicity of less than 35 degrees as a contact angle of water for a long period of time, it is appropriate to use a hydrophilic inorganic amorphous substance. At this time, in order to quickly form a water film, a stable substance exhibiting as high a hydrophilicity as possible is appropriate.

(Hydrophilic inorganic amorphous substance) The hydrophilic inorganic amorphous substance in the present invention is a substance which easily generates chemically adsorbed water on its surface, that is, an inorganic amorphous substance.

As such a substance, among the inorganic amorphous substances, the amorphous metal oxide forms chemically adsorbed water on the surface and exhibits hydrophilicity, and in addition, polysilazane and the like can be mentioned.

In a preferred embodiment, an alkali silicate, an alkali borosilicate, an alkali zirconate, an alkali phosphate and a metal phosphate easily form a chemically adsorbed water layer in the presence of water. It is good because it can exhibit hydrophilicity.

Of these, alkali silicates are particularly preferred.

Here, as the alkali silicate, sodium silicate, potassium silicate, lithium silicate and ammonium silicate are preferable. In general, it is said that the adhesion is stronger in the order of sodium silicate and potassium silicate, and the water resistance is stronger in the order of ammonium silicate and lithium silicate.However, considering the film properties, film hardness, water resistance, etc., it is more likely that lithium silicate is included. It is suitable.

It is preferable that the coating of the hydrophilic member of the present invention contains boric acid and / or a boric acid compound because the water resistance and the chemical durability can be improved. As boric acid or boric acid compounds, orthoboric acid, metaboric acid,
Tetraboric acid, zinc borate, potassium borate, sodium borate, barium borate, magnesium borate, lithium borate, and other borate esters.

Further, it is preferable that the coating of the hydrophilic member of the present invention contains phosphoric acid and / or a phosphoric acid compound since the curing of the film can be promoted and the durability of the film can be improved. Phosphoric acid or phosphoric acid compounds include phosphoric anhydride, metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, zinc phosphate, zinc hydrogen phosphate, aluminum phosphate, aluminum hydrogen phosphate, phosphoric acid Ammonium, ammonium hydrogen phosphate, sodium ammonium hydrogen phosphate, potassium phosphate, potassium hydrogen phosphate,
Examples include, but are not limited to, calcium phosphate, calcium hydrogen phosphate, sodium phosphate, lithium hydrogen phosphate, and other phosphate esters.

Further, the coating of the hydrophilic member of the present invention contains a precursor of a substance which becomes Al2O3 or ZrO2 by heat treatment, so that A2 is contained in the SiO2 structure in the alkali silicate.
It is preferable because l and Zr are taken in and the chemical durability can be improved.

Examples of the precursor of the substance which becomes Al2O3 by the heat treatment include boehmite, gibbsite, aluminum acetate, aluminum alkoxide, aluminum alcoholate, aluminum acetylacetonate, aluminum chloride and the like.

Examples of the precursor of the substance which becomes ZrO2 by heat treatment include zirconium chloride, zirconium oxychloride, zirconium chloride, zirconium nitrate, zirconium acetylacetonate, zirconium butoxide, zirconium propoxide and the like.

(Hydrophilic Metal Oxide Particles) In the present invention, Al 2 O 3 and ZrO 2 are easily available and suitable for the metal oxide particles. Further, the metal oxide particles may contain SiO2, TiO2, and SnO2.

In addition, as long as oxides can be formed on at least the surface of the particles, nitrides, borides, carbides, and the like also cover the surface layer with an oxide film or hydrolyze, thereby forming a chemically adsorbed water layer. It is generally known and can be used to form and exhibit hydrophilicity.

The metal oxide particles have a particle size of 10 to 30.
By setting the value to 0 nm, the value of Rz can be set.
At this time, the shape of the particles is not limited in terms of forming the Rz, and examples thereof include a spherical shape, a rectangular shape, a flat shape, a feather shape, a feather shape, and a chain shape. In the hydrophilic film, the method of forming the above Rz is not particularly limited, but irregularities can be formed by dispersing metal oxide particles in the film.

(Hydrophilic member) The hydrophilic member in the present invention is characterized in that the surface of the coating has a fine uneven structure. The concavo-convex structure of the coating is defined by a ten-point average roughness (Rz) measured using an atomic force microscope having a side of 5 μm square on any side of the coating surface. That is, 5
The difference between the average of the absolute values of the altitudes of the peaks from the highest to the fifth in the μm × 5 μm square and the average of the absolute values of the altitudes of the valleys from the lowest to the fifth. Stipulated. Since the amount of water that can be retained on the surface corresponds to the thickness of the water film, the amount of water retained on the surface can be controlled by appropriately setting the value of Rz.

When the value of Rz is too small, a uniform and sufficient water film cannot be maintained and formed, and when the value is too large, transparency, film hardness and durability are lost. Therefore, the value of Rz in the present invention is preferably 20 nm or more and 300 nm or less, more preferably 30 nm or more and 200 nm or less, and 40 nm or less.
Above 150 nm is most preferable.

As a preferred embodiment of the above-mentioned hydrophilic member, a coating comprising alkali silicate and metal oxide particles is formed,
In addition, a fine uneven structure is formed on the surface of the coating.

The metal oxide particles include Al 2 O 3 and ZrO 2
Are available and preferred. Furthermore, SiO2, TiO
2, may contain SnO2.

(Substrate) The substrate to which the present invention can be applied may be any material such as an inorganic material, a metal material, an organic material, or a composite thereof as long as it is an article expected to have an antifogging effect and a hydrophilic effect. There is no particular limitation.

Among them, articles requiring antifogging and antifouling properties include tiles, sanitary ware, tableware, glass,
Mirrors, reflectors, protective plates, films, protective films, ceramics, scallops, cement, wood, resins, metals, ceramics and other building materials, daily necessities, etc. Mirrors and reflectors that require functions, protective plates and protective films that require light transmission are particularly suitable.

As a method for producing a hydrophilic member of the present invention, a step of preparing a substrate, a step of preparing a mixture of alkali silicate and metal oxide particles, and coating the substrate with the mixture to form a coating And, if necessary, a step of heat-treating at least the coated surface of the coating. At this time, a coating having a fine uneven structure can be formed on the surface of the substrate by the step of forming the coating.

In the mixture of the alkali silicate and the metal oxide particles in the above step, the alkali silicate SiO 2
The concentration (A) is 0.01 wt% or more and 5 wt% or less, and the concentration (B) of the metal oxide particles is A: B = 1: 0.1
When it is in the range of １ ： 1: 10, the above-mentioned water film can be formed and maintained, and a film having high durability can be formed.
At this time, in the mixture of the alkali silicate and the metal oxide particles, boric acid, boric acid compound, phosphoric acid, phosphoric acid compound,
A precursor of a substance which becomes Al2O3 or ZrO2 by heat treatment can be included.

The method for producing a hydrophilic member according to the present invention includes a step of preparing a base material, a step of preparing a mixture of alkali silicate and metal oxide particles or a suspension of metal oxide, Coated with the mixture or the suspension,
A step of forming a coating, a step of preparing an alkali silicate, a step of further applying an alkali silicate to the coating surface to form a coating twice, and, if necessary, heat-treating at least the coating surface of the coating. Step.
At this time, by the step of forming the twice-coated material, it is possible to form a twice-coated film having a fine uneven structure on the surface of the substrate, and in the mixture of the alkali silicate and the metal oxide particles, The SiO2 concentration (A) of the silicate is 0.001 wt% or more and 5 wt% or less, and the concentration (B) of the metal oxide particles is A: B = 1: 0.1 to 1: 100.
When it is in the range of 0, a water film can be formed and maintained, and a highly durable film can be formed. At this time, the mixture of the alkali silicate and the metal oxide particles or the alkali silicate can contain boric acid, a boric acid compound, a phosphoric acid, a phosphoric acid compound, and a precursor of a substance that becomes ZrO2 by heat treatment.

The mixture of the alkali silicate and the metal oxide particles or the solvent of the alkali silicate in the present invention is not limited, and water or alcohol is preferred from the viewpoint of stability and workability.

The means for forming the coating is not particularly limited, but the coating can be formed by applying the coating by a method such as spray coating, flow coating, spin coating, dip coating or roll coating and then drying.

The hydrophilic member of the present invention can be subjected to a heat treatment at a surface temperature of the film of 80 ° C. or more and 500 ° C. or less, if necessary. If the temperature is too low, water resistance and the like cannot be satisfied with respect to members requiring durability.
When the heat treatment is performed at a temperature of 00 ° C. or higher, the structure on the surface of the inorganic substance is stabilized, and even if water molecules are present on the surface of the coating film, the generation of chemically adsorbed water is insufficient and the hydrophilicity is deteriorated, which is not suitable.
Therefore, when heat treatment is performed, the hydrophilic member can be formed by heat treatment at the above surface temperature.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. << Anti-fogging function test >> The test evaluation method used in the anti-fogging function test is described below. Table 1 shows the test results.

[0042]

[Table 1]

[Water film holding water amount] First, the room temperature is 15 ° C. or higher and 2
Set to less than 5 degrees and relative humidity between 30% and 80%
In the following environment, a test specimen of about 10 cm ² previously stabilized in the same environment for 1 hour or more is placed so that the hydrophilic surface is almost vertical. Thereafter, only the coating surface was wetted with water having a water temperature substantially equal to a room temperature of 15 ° C. or more and 25 ° C. or less. After 15 seconds, water accumulated at the lower portion was removed, and the weight of the water was measured with an electronic balance. After the measurement, the surface area of the sample was measured, and the amount of water per 10 cm ² was calculated. [Contact Angle] The specimen was left in a room in an environment of 20 ° and 45% RH for 1 week or more, and a contact angle meter CA manufactured by Kyowa Interface Science Co., Ltd. was used.
The contact angle of water was measured using a model -X150. [Roughness Measurement] The ten-point average roughness was measured with a scanning probe microscope SPM-9500 manufactured by Shimadzu Corporation. [Pencil hardness test] A pencil having a density symbol specified in JIS-S-6006 (pencil and color pencil) is applied to the coating surface 45
Hold the pencil at a speed of about 3 mm per second from the front to the front at a speed of about 3 mm per second. The pencil hardness was determined. [Anti-Fogging Test] A test body having a surface temperature of 5 ° C. was placed in a bathroom, and a hot water shower was used to make an environment of 20 ° 95% RH. Thereafter, water was applied to the surface of the test sample, and the occurrence of fogging after 10 minutes was observed. At this time, those in which no fogging occurred were evaluated as ○, and those in which fogging occurred were evaluated as x.

Comparative Example 1 A commercially available glass mirror having a size of 10 cm square was prepared, washed with a neutral detergent, and air-dried.

Comparative Example 2 A commercially available 10 cm square plate glass was prepared, washed with cerium oxide powder, and then lithium silicate (lithium silicate 35 (manufactured by Nissan Chemical Industries, Ltd.))
Is diluted to 1% of SiO2 content, and applied with a roll coater.
Heat treatment was performed at 600 ° C. for 10 minutes.

Example 1 A commercially available stainless steel reflecting mirror was cut into a 10 cm square and washed with cerium oxide powder.
Lithium silicate (lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd.)) and alumina particles (alumina sol 520
(Particle size: 10 to 20 nm, manufactured by Nissan Chemical Industry Co., Ltd.)) was mixed with a SiO2 concentration of 0.5% and an Al2O3 concentration of 0.5%.
The mixture was adjusted to 5%, a small amount of a 1% solid solution of aluminum phosphate was added thereto, and the mixture was applied by spin coating. Thereafter, heat treatment was performed at 250 ° C. for 5 minutes.

Example 2 A 10 cm square transparent acrylic plate was prepared, degreased and washed, and then lithium silicate (lithium silicate 75
(Manufactured by Nippon Chemical Industry Co., Ltd.)) and zirconia particles (zirconia sol NZS-30B, particle diameter 70 nm, manufactured by Nissan Chemical Industry Co., Ltd.) were each 0.5% SiO2 concentration, ZrO
2 The mixture was adjusted to a concentration of 0.5%, and applied with a dip coater.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 1/10 G02B 1/10 Z

Claims (17)

[Claims] Claims: 1. A substrate and a hydrophilic substrate formed on the substrate.
At least an amorphous material and hydrophilic metal oxide particles.
And a hydrophilic coating comprising:
By attaching water and holding the hydrophilic coating vertically
When the excess water has been removed, the hydrophilic coating is applied to the hydrophilic coating.
Weight of attached water film is 10cm ^Two0.23g to 0.
A hydrophilic member weighing 50 g. 2. The weight of the water film is 0.23 g to 0.35.
The hydrophilic member according to claim 1, which is g. 3. The method according to claim 2, wherein the hydrophilic metal oxide particles are Al2O.
3. The hydrophilic member according to claim 1, comprising ZrO2. 4. The method according to claim 1, wherein the hydrophilic inorganic amorphous material is an alkali silicate, an alkali borosilicate, an alkali zirconate,
The hydrophilic member according to any one of claims 1 to 3, comprising at least one selected from the group consisting of an alkali phosphate and a metal phosphate. 5. The hydrophilic member according to claim 1, wherein the hydrophilic inorganic amorphous substance is an alkali silicate. 6. The method according to claim 1, wherein the hydrophilic metal oxide particles further comprise SiO 2.
The hydrophilic member according to any one of claims 1 to 5, comprising 2, TiO2, and SnO2. 7. The hydrophilic member according to claim 1, wherein the mode of the particle diameter of the hydrophilic metal oxide particles is from 10 to 300 nm. 8. The ten-point average roughness (Rz) measured using an atomic force microscope having a side of 5 μm square at an arbitrary point on the surface of the hydrophilic film is 20 nm or more and 300 nm or less. Item 8. The hydrophilic member according to any one of Items 7 to 10. 9. The ten-point average roughness (Rz) measured using an atomic force microscope having an arbitrary side of 5 μm square on an arbitrary surface of the hydrophilic coating surface is 30 nm or more and 200 nm or less. Hydrophilic member. 10. The method of claim 1, wherein any one of the hydrophilic coating surfaces
The hydrophilic member according to claim 8, wherein the ten-point average roughness (Rz) measured using an atomic force microscope having a side of 5 µm square is 40 nm or more and 150 nm or less. 11. The hydrophilic member according to claim 1, wherein a static contact angle of water on the surface of the hydrophilic film is less than 35 degrees. 12. The first hydrophilic coating, wherein the hydrophilic coating is substantially composed of the hydrophilic inorganic amorphous substance and the hydrophilic metal oxide particles, and an outermost layer on the first hydrophilic coating. And at least a second hydrophilic coating substantially formed of the hydrophilic inorganic amorphous material.
The hydrophilic member according to any one of claims 1 to 11. 13. A method in which heat treatment is carried out in the hydrophilic coating by heat treatment.
13. The hydrophilic member according to claim 1, further comprising a precursor of a substance that becomes l2O3 and ZrO2. 14. The hydrophilic member according to claim 1, wherein the substrate is selected from the group consisting of an inorganic material, a metal material, an organic material, and a composite thereof. 15. The base material is tile, sanitary ware, tableware,
Glass, glass lid, mirror, reflector, protective plate, film,
The hydrophilic member according to any one of claims 1 to 14, wherein the hydrophilic member is selected from the group consisting of a protective film, a ceramic, a calcium silicate plate, cement, wood, resin, metal, and ceramic. 16. The bath according to claim 1, wherein said base material is a bathroom member.
The hydrophilic member according to any one of claims 1 to 15. 17. The hydrophilic member according to claim 1, wherein the substrate is a bathroom mirror.