JP2021133523A - Super-hydrophilic membrane and method for producing the same, and optical member - Google Patents

Abstract

To provide: a super-hydrophilic membrane that has a super-hydrophilic property and has both a high-temperature and high-humidity resistance and a heat cycle resistance; a method for producing super-hydrophilic membrane; and an optical member using the super-hydrophilic membrane.SOLUTION: The super-hydrophilic membrane of the present invention is a super-hydrophilic membrane that has at least one layer of sodium-containing layer on the substrate, and is characterized in that the membrane is a super-hydrophilic membrane that further has a water contact angle control layer on the outermost surface side when viewed from the sodium-containing layer.SELECTED DRAWING: Figure 5

Description

The present invention relates to a superhydrophilic film, a method for producing the same, and an optical member using the same. More specifically, the present invention relates to a superhydrophilic film having excellent high temperature and high humidity resistance and heat cycle resistance, a method for producing the same, and an optical member using the same.

In recent years, there have been strict requirements for guaranteeing environmental resistance in optical members such as lenses, antibacterial cover members, antifungal coating members, and mirrors. For example, in a salt spray test on a lens, when silicon dioxide (hereinafter referred to as "SiO ₂ "), which is a component of the antireflection layer on the lens surface, dissolves in salt water and the light reflectance changes, ghosts or It causes flare.

In addition, dirt such as water droplets and mud often adheres to the lens. Depending on the degree of water droplets adhering to the lens, the image captured by the camera may become unclear. Further, the outermost layer of the optical member is required to be able to maintain superhydrophilicity when stored in a high temperature and high humidity environment for a long period of time, and the surface of various optical members is provided with durability. A method for imparting a hydrophilic film has been studied.

As a typical method for forming a hydrophilic film,
1) A method of forming a hydrophilic film by a wet method using an inorganic material,
2) A method of forming a hydrophilic film by a wet method using an organic material,
3) A method of forming a hydrophilic film by a dry film forming method using an inorganic material,
And so on.

As the forming method according to the above items 1) and 2), for example, in Patent Document 1, an antifogging material for an organic base material containing a specific alcohol solvent and an organosilica sol is brought into contact with the organic base material. A method of coating, swelling the surface of an organic base material with the solvent, and invading the swelled surface with an organosilica sol to form a hydrophilic silica film is disclosed. According to the method described in Patent Document 1, it is said that an organic base material having a low water contact angle and excellent antifouling property, antifog property, adhesiveness and durability can be obtained.

However, when the silica film formed on the surface is applied to an optical member, for example, an in-vehicle camera, salt water contained in sea breeze, acid rain, chemicals such as detergents and waxes used for car washing, etc. There is a risk of surface deterioration and deterioration due to the above. _{For example, since the surface of a coated silica (SiO 2} ) film as disclosed in Patent Document 1 is porous and brittle, SiO ₂ is dissolved in a salt spray test, resulting in a thin film and maintaining the above performance. That is difficult. Further, since the silica film has a porous surface, there is a problem that the wear resistance is lowered.

Further, the method described in Patent Document 1 is a film forming method by a wet coating method, and the formed hydrophilic film has low adhesion and poor durability against salt spray and abrasion resistance. In addition, since the drying process is difficult to stabilize from the coating process, the durability performance of the formed hydrophilic film varies.

On the other hand, as a method for forming a dry film of a hydrophilic film according to item 3), for example, Patent Document 2 discloses it. _{Patent Document 2 discloses a multilayer film having a base layer and a hydrophilic layer containing phosphoric acid (P 2} O ₅ ) on a base material, and is said to have excellent sustainability of hydrophilic performance. However, the method proposed in Patent Document 2 has a problem in high temperature and high humidity environment resistance (for example, temperature: 85 ° C., humidity: 85% RH).

Further, another method for forming a hydrophilic layer by dry film formation is disclosed in Patent Document 3. In Patent Document 3, a laminate of a base material / dielectric multilayer film / TiO _2- containing layer (photocatalyst layer) / SiO _{2- containing layer is prepared, and a SiO 2} film which is a porous and relatively coarse film is prepared by a vapor deposition method. Although it is disclosed that a hole at the atomic level is formed by forming a film to expose the _{photocatalytic function from the TiO 2} containing layer to the surface, this has the following five problems.

1) Since _{the gap between the SiO 2} films is an atomic level gap and is insufficient, the photocatalyst function cannot be efficiently taken out, and there is no other way but to increase the amount of _{TiO 2 which is a photocatalyst layer.} In this method, since _{the thickness of the TiO 2} layer is increased, the antireflection property is inferior, and the manufacturing error sensitivity of the antireflection performance is increased, which causes a problem in mass productivity.

2) Further, since _{the gaps between the SiO 2} films are atomic-level pores, the holes are clogged within 1 hour of the high-temperature and high-humidity test at 80 ° C. and 90% RH, and the photocatalytic effect is inactivated.

3) Further, in the case of the SiO ₂ film, the film becomes weak due to the holes at the atomic level, and as described above, the salt water resistance is lowered and the film cannot be used in a harsh environment such as an in-vehicle camera.

4) The _{hydrophilic function of the SiO 2} film has a problem that the water contact angle becomes large and the water becomes water repellent during a long-time high-temperature and high-humidity test.

5) Finally, if the SiO ₂ film is used, it is inferior in scratch resistance and easily peeled off, and the light reflectance changes.

Therefore, the appearance of a super-hydrophilic film having excellent adhesion and satisfying both high temperature and high humidity resistance and heat cycle resistance at the same time is awaited.

Japanese Unexamined Patent Publication No. 2013-203774 International Publication No. 2017/170218 Japanese Unexamined Patent Publication No. 10-36144

The present invention has been made in view of the above problems and situations, and the problem to be solved thereof is to provide a superhydrophilic film having excellent high temperature and high humidity resistance and heat cycle resistance, a method for producing the same, and an optical member using the same. That is.

In order to solve the above-mentioned problems, the present inventor has formed a sodium-containing control layer as the outermost surface layer on the surface side of the sodium-containing layer on the substrate in the process of examining the cause of the above-mentioned problems. Heat cycle resistance is improved by preventing the movement of sodium from the layer to the surface by a water contact angle control layer containing, for example, magnesium, calcium, cerium, phosphorus, etc., and high temperature and high humidity resistance by the sodium-containing layer. It has been found that an excellent superhydrophilic film can be obtained, and the present invention has been achieved.

That is, the above problem according to the present invention is solved by the following means.

1. 1. A superhydrophilic membrane having at least one sodium-containing layer on the substrate.
A superhydrophilic membrane characterized by having at least one water contact angle control layer on the surface side of the sodium-containing layer.

2. The superhydrophilic membrane according to item 1, wherein the water contact angle control layer is a sodium-free layer.

3. 3. The superhydrophilic membrane according to item 1 or 2, wherein the water contact angle control layer contains at least one element selected from magnesium, calcium, cerium and phosphorus.

4. The superhydrophilic film according to any one of items 1 to 3, wherein the thickness of the sodium-containing layer is in the range of 1 to 500 nm.

5. The superhydrophilic film according to any one of items 1 to 4, wherein the layer thickness of the water contact angle control layer is in the range of 0.1 to 50 nm.

6. The superhydrophilic membrane according to any one of items 1 to 5, wherein one or more units composed of the sodium-containing layer and the water contact angle control layer are laminated.

7. The superhydrophilic membrane according to any one of items 1 to 6, wherein the sodium content in the sodium-containing layer is in the range of 1.0 to 20% by mass.

8. From the third item, the content of at least one element selected from magnesium, calcium, cerium and phosphorus in the water contact angle control layer of at least one layer is in the range of 0.1 to 20% by mass. The superhydrophilic membrane according to any one of items up to item 7.

9. A reflectance adjusting layer unit is provided between the substrate and the sodium-containing layer, and the average light reflectance in the wavelength range of 450 to 780 nm is 3.0% or less. The superhydrophilic membrane according to any one of items 1 to 8.

10. The superhydrophilic film according to any one of items 1 to 9, further comprising an wear resistance improving layer on the water contact angle control layer.

11. On the substrate, as the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer.
A second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer is provided in this order.
The superhydrophilic film according to Item 9 or 10, wherein the layer farthest from the substrate of the first reflectance adjusting layer unit is a photocatalytic layer containing a metal oxide having a photocatalytic function. ..

12. The superhydrophilic film according to Item 11, wherein the superhydrophilic film has pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and expose the surface of the photocatalyst layer.

13. A method for producing a superhydrophilic film, which comprises producing the superhydrophilic film according to any one of items 1 to 12.

14. A step of forming a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer on the substrate.
At least, a step of forming a second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer, and
Item 13. The method for producing a superhydrophilic membrane according to the above.

15. 13. A method for producing a hydrophilic film.

16. The method for producing a superhydrophilic film according to any one of items 13 to 15, wherein the water contact angle control layer is formed as a sodium-free layer.

17. The method for producing a superhydrophilic film according to any one of items 13 to 16, wherein at least one layer of the sodium-containing layer and the water contact angle control layer is formed by a dry film forming method.

18. Further, a reflectance adjusting layer unit is formed, and at least one layer of the sodium-containing layer, the water contact angle control layer, and the reflectance adjusting layer unit is formed by a vapor deposition method under a condition where the amount of gas introduced is 5 sccm or more. The method for producing a superhydrophilic film according to any one of items 13 to 17, wherein the film is formed.

19. As the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer.
The item according to any one of items 13 to 18, wherein the second reflectance adjusting layer unit composed of the low refractive index layer, the high refractive index layer and the sodium-containing layer is formed in this order. Method for producing a superhydrophilic membrane.

20. Any one of items 13 to 19, wherein the sodium content in the raw material used for forming the film of at least one layer of the sodium-containing layer is in the range of 1.0 to 20% by mass. The method for producing a superhydrophilic membrane according to.

21. The content of at least one element selected from magnesium, calcium, cerium and phosphorus in the raw material used for forming the film of the water contact angle control layer of at least one layer is in the range of 0.1 to 20% by mass. The method for producing a superhydrophilic membrane according to any one of items 13 to 20, which is characteristic.

22. Items 13 to 21 are characterized by having a step of forming a plurality of pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and partially expose the surface of the photocatalyst layer. The method for producing a superhydrophilic membrane according to item 1.

23. An optical member comprising the superhydrophilic film according to any one of items 1 to 12.

24. The optical member according to item 23, wherein the optical member is a lens, an antibacterial cover member, an antifungal coating member, or a mirror.

By the above means of the present invention, it is possible to provide a superhydrophilic film having excellent adhesion, high temperature and high humidity resistance and heat cycle resistance, a method for producing the same, and an optical member using the same.

The mechanism of expression or mechanism of action of the effect of the present invention is inferred as follows.

As a result of diligent studies on the above problems, the superhydrophilic membrane of the present invention has a structure that achieves both high temperature and high humidity resistance and heat cycle resistance. By forming a layer, more specifically, a sodium-free layer, the water contact angle control layer prevents the movement of sodium from the sodium-containing layer to the surface side, thereby improving heat cycle resistance and improving heat cycle resistance. , It has been found that a superhydrophilic film capable of exhibiting excellent high temperature and high humidity resistance due to the sodium-containing layer can be obtained.

Conventionally, as a hydrophilic film, as shown in FIG. 1 (see Patent Document 3), the substrate 2 is composed of a low refractive index layer and a high refractive index layer, and has a TiO ₂ containing layer (photocatalyst layer) on the uppermost layer. The laminate (superhydrophilic film 1) composed of the first reflectance adjusting layer unit 5 and _{the low refractive index layer 11A containing SiO 2 on} the outermost surface does not contain sodium, so that the temperature is 85 ° C. and 85% RH. As a result of the high temperature and high humidity test, the contact angle of the surface increased, and there was a problem in high temperature and high humidity resistance. Further, since _{the gaps between the SiO 2} films are molecular-level pores, the photocatalyst is clogged.

On the other hand, a first reflectance adjusting layer unit composed of a low refractive index layer and a high refractive index layer on the substrate _{and having a TiO 2} containing layer (photocatalyst layer) on the uppermost layer is formed, and sodium is further formed as the outermost layer on the first reflectance adjusting layer unit. A structure in which a sodium-containing layer containing a component is laminated exerts an extremely excellent effect on high-temperature and high-humidity resistance, but when the sodium component constituting the sodium-containing layer is present on the surface, heat under more severe conditions is obtained. Further techniques for achieving a higher quality ultrahydrophilic film with slightly reduced cycle resistance (for example, a process of repeating a high temperature environment (65 ° C) and an extremely low temperature environment (-15 ° C) in a constant cycle). Improvement is required.

Further, as shown in FIG. 2, a first reflectance adjusting layer unit 5 composed of a low refractive index layer and a high refractive index layer on the substrate _{and having a TiO 2} containing layer (photocatalyst layer) on the uppermost layer is formed. Further, even in the superhydrophilic film 1 having the structure in which the water contact control layer 4 is independently formed as the outermost layer on the superhydrophilic film 1, the high temperature and high humidity resistance and the abrasion resistance are lowered, the contact angle of the surface is increased, and the hydrophilicity is deteriorated. It has been found.

As a result of diligent studies through experiments and the like on a method for achieving both high temperature and high humidity resistance and heat cycle resistance in a harsh environment, the present inventors have conducted a diligent study, and as a result, the sodium component is on the surface side from the viewpoint of improving high temperature and high humidity characteristics. It was found that it is not essential that it is present in, and that it is possible to develop high temperature and high humidity resistance by being present in a region having a depth of 50 nm or less from the surface. As a result of further studies based on the above findings, the water contact angle control layer of the thin film, specifically, the sodium-free layer is provided on the surface side of the sodium-containing layer, so that the surface layer of the sodium component in the sodium-containing layer is provided. It was possible to prevent diffusion into the part, develop high-temperature and high-humidity resistance due to the sodium-containing layer, and at the same time, obtain a highly durable superhydrophilic film that is strong even under severe heat cycle conditions.

Further, in the design of the water contact angle control layer, as a result of studying a constituent material capable of exhibiting the above effect, the water contact angle control layer is a material that does not impair the hydrophilicity of the sodium-containing layer. However, it is necessary to use a material that can suppress the movement of sodium to the surface with a thin layer thickness, and it has been found that magnesium, calcium, cerium or phosphorus are effective as such a material.

Cross-sectional view showing an example of the configuration of a conventional hydrophilic film Cross-sectional view showing another example of the configuration of the hydrophilic film of the conventional example Cross-sectional view showing an example of the basic configuration of the superhydrophilic membrane of the present invention (Embodiment 1) A cross-sectional view showing an example of a specific configuration of the first reflectance adjusting layer unit shown in FIG. Cross-sectional view showing another example of the basic configuration of the superhydrophilic membrane of the present invention (Embodiment 2) Cross-sectional view showing an example of a specific configuration of the second reflectance adjusting layer unit constituting the superhydrophilic film. Cross-sectional view showing another example of a specific configuration of the second reflectance adjusting layer unit constituting the superhydrophilic film. Cross-sectional view showing another example of the specific configuration of the superhydrophilic membrane of the present invention (Embodiment 3). FIG. 8 is a cross-sectional view showing an example of a specific configuration of the superhydrophilic film of the present invention in which an abrasion resistance improving layer is formed on the outermost surface of the configuration of FIG. 8 (Embodiment 4). Schematic diagram of vacuum vapor deposition equipment used in the IAD method Flowchart of the process of forming pores in the superhydrophilic membrane Cross-sectional view showing an example of a configuration in which pores are formed in a superhydrophilic membrane to expose a photocatalyst layer (Embodiment 5). Manufacturing flow showing an example of forming pores in a superhydrophilic membrane Cross-sectional view of the superhydrophilic membrane 1 produced in the examples

The superhydrophilic membrane of the present invention is a superhydrophilic membrane having at least one layer of sodium-containing layer on the substrate, and is characterized by having at least one layer of contact angle control layer on the water surface side with respect to the sodium-containing layer. And. This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, it is preferable that the water contact angle control layer is a sodium-free layer in that heat cycle resistance can be further improved.

Further, when the water contact angle control layer contains at least one element selected from magnesium, calcium, cerium and phosphorus, the effect of suppressing the movement of the sodium component can be exhibited even in a trace amount, and even though it is a thin film. It is preferable in that a water contact angle control layer having an excellent sodium trapping ability can be formed, and the heat and moisture resistance resistance of the lower sodium-containing layer can be effectively brought out.

Further, it is preferable that the thickness of the sodium-containing layer is in the range of 1 to 500 nm, because it is possible to design antireflection and to achieve both high temperature and high humidity resistance.

Further, when the layer thickness of the water contact angle control layer is in the range of 0.1 to 50 nm, the high temperature and high humidity resistance of the sodium-containing layer located in the lower layer can be maintained, and sufficient heat cycle resistance is exhibited. It is preferable in that it can be done.

Further, it is preferable that one or more units composed of the sodium-containing layer and the water contact angle control layer are laminated, because more excellent heat cycle resistance can be exhibited.

Further, when the sodium content in at least one layer of the sodium-containing layer is in the range of 1.0 to 20% by mass, sufficient high-temperature and high-humidity resistance can be obtained and the occurrence of haze is suppressed. It is preferable in that it can be used.

Further, it is desired that the content of at least one element selected from magnesium, calcium, cerium and phosphorus in the water contact angle control layer is within the range of 0.1 to 20% by mass for the desired high temperature and high humidity resistance and heat. It is preferable in that a cycle can be obtained.

Further, it is necessary that at least one reflectance adjusting layer unit is provided between the substrate and the sodium-containing layer, and the average light reflectance in the wavelength range of 450 to 780 nm is 3.0% or less. It is preferable in that it can be a superhydrophilic film having excellent light transmittance.

Further, it is preferable to provide a wear resistance improving layer on the outermost surface layer from the viewpoint that excellent wear resistance can be obtained even after the heat cycle treatment.

In the method for producing a superhydrophilic film of the present invention, a step of forming a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer on the substrate, and at least A step of forming a second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer, and at least one layer of sodium and the sodium on the reflectance adjusting layer unit. It is preferable to have a step of forming at least one layer of the water contact angle control layer on the surface side of the containing layer in that a superhydrophilic film having a desired constitution can be formed.

Further, in the method for producing a superhydrophilic film of the present invention, it is preferable to form the water contact angle control layer as a sodium-free layer containing no sodium, because sufficient heat cycle resistance can be exhibited.

Further, in the method for producing a superhydrophilic film of the present invention, forming at least one layer of the sodium-containing layer and the water contact angle control layer by a dry film forming method improves the adhesion between the layers and makes water. It is preferable in that it improves the spray test and wear resistance.

Further, in the method for producing a superhydrophilic film of the present invention, a reflectance adjusting layer unit is further formed, and at least one layer of the sodium-containing layer, the water contact angle control layer and the reflectance adjusting layer unit is vapor-deposited. It is preferable to form a film under the condition that the amount of gas introduced is 5 sccm or more, because a dense layer can be formed.

In the present invention, "sccm" is an abbreviation for standard cc / min, and is a unit indicating how many cc flowed per minute at 1 ^{atm (atmospheric pressure 1 × 10 13 hPa) and 0 ° C.}

Further, in the method for producing a superhydrophilic film of the present invention, the reflectance adjusting layer unit includes a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer. By forming the second reflectance adjusting layer unit composed of the low refractive index layer, the high refractive index layer and the sodium-containing layer in this order, a superhydrophilic film having better characteristics can be formed. It is preferable in that.

Further, in the method for producing a superhydrophilic film of the present invention, it is desirable that the sodium content in the raw material used for forming at least one layer of the sodium-containing layer is in the range of 1.0 to 20% by mass. It is preferable in that a sodium-containing layer can be formed.

Further, in the method for producing a superhydrophilic film of the present invention, the content of at least one element selected from magnesium, calcium, cerium and phosphorus in the raw materials used for forming the film of the water contact angle control layer of at least one layer is determined. The content is preferably in the range of 0.1 to 20% by mass because it has a desired configuration and can form a water contact angle control layer capable of suppressing exposure of sodium to the surface.

Further, the method for producing a superhydrophilic film of the present invention includes a step of forming a plurality of pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and partially expose the surface of the photocatalyst layer. , It is preferable in that an excellent photocatalytic effect can be exhibited.

The superhydrophilic film of the present invention is suitably provided for an optical member, and the fact that the optical member is a lens, an antibacterial cover member, an antifungal coating member or a mirror is from the viewpoint of fully utilizing the effects of the present invention. preferable.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

<< Basic composition of superhydrophilic membrane >>
The superhydrophilic membrane of the present invention is characterized by having at least one layer of sodium on the substrate and at least one layer of water contact angle control layer on the surface side of the sodium-containing layer. ..

FIG. 3 is a cross-sectional view showing an example of the basic configuration of the superhydrophilic membrane of the present invention (Embodiment 1).

In the superhydrophilic film 1 shown in FIG. 3, a first reflectance adjusting layer 5 shown as an example in FIG. 4 is provided on a substrate 2, a sodium-containing layer 3 is formed on the first reflectance adjusting layer 5, and an upper layer of the sodium-containing layer 3 is formed. It is configured to have at least one water contact angle control layer 4 on the side.
As described above, the superhydrophilic membrane of the present invention is characterized by having at least one water contact angle control layer 4 on the upper layer side of the sodium-containing layer 3, but more specifically, the following layer arrangement. Can be mentioned.
1) A configuration in which a water contact angle control layer 4 is arranged at a position directly adjacent to the surface side of the sodium-containing layer 3 according to the present invention.
2) A water contact angle control layer 4 is provided on the surface side of the sodium-containing layer 3 according to the present invention, and an intermediate layer, for example, a SiO _2- containing layer, is provided between the sodium-containing layer 3 and the water contact angle control layer 4. 3) A configuration in which a plurality of sets of units composed of the sodium-containing layer 3 and the water contact angle control layer 4 are laminated, and the water contact angle control layer 4 is also provided below the sodium-containing layer 3.
4) A configuration in which a water contact angle control layer 4 is provided on the surface side of the sodium-containing layer 3 according to the present invention, and a functional layer, for example, an abrasion resistance improving layer is further provided on the surface side of the water contact control layer. , The structure in which the water contact angle control layer 4 is not the outermost layer,
And so on.

In the superhydrophilic film of the present invention, it is preferable that the water contact angle control layer is a sodium-free layer, and further, the water contact angle control layer is selected from magnesium, calcium, cerium and phosphorus. It is a preferable embodiment that the composition contains at least one element.

The "water contact angle control layer" referred to in the present invention can control the water contact angle of the superhydrophilic membrane within a predetermined range specified below in order to develop the heat cycle resistance of the superhydrophilic membrane. A layer that has a function. The water contact angle control layer may have various purposes and functions in addition to the above functions as long as the effects of the present invention are not impaired.

Specifically, "high temperature environment (treatment at 65 ° C for 4 hours) → temperature lowering to -15 ° C at 1 ° C / 1 minute → ultra-low temperature environment (treatment at -15 ° C for 4 hours) → 65 ° C at 1 ° C / minute. The water contact angle after repeating this for 6 cycles is maintained at 20 ° or less, and the water contact angle A after the heat cycle treatment is not yet set. It is defined as a layer having a characteristic that the change width (mainly the rising width) of the water contact angle is within + 20 ° with respect to the water contact angle B of the treated superhydrophilic membrane.

The water contact angle referred to in the present invention is such that at a temperature of 23 ° C. and a humidity of 50% RH, about 10 μL of pure water, which is the standard liquid, is dropped onto the sample, and for example, a G-1 device manufactured by Elma Co., Ltd. is used. Then, 5 points on the sample are measured, the average contact angle is obtained from the average of the measured values, and this is used as the water contact angle. The time until the contact angle measurement is measured 5 seconds after the standard liquid is dropped.

In the water contact angle control layer according to the present invention, for example, the sodium in the sodium-containing layer moves to the surface of the superhydrophilic membrane to change the water contact angle on the surface of the superhydrophilic membrane, and as a result, the heat of the superhydrophilic membrane is changed. It is preferable that the layer has a control (adjustment) function that can prevent the phenomenon of deteriorating the cycle resistance.

Further, the "sodium-free layer" in the present invention means that the content of sodium with respect to the total mass of the sodium-free layer is less than 1.0% by mass, and in the sodium-free layer satisfying this condition, The heat cycle resistance of the water contact angle control layer defined above can be realized, preferably less than 0.1% by mass including 0, and in particular, 0% by mass containing no sodium at all. preferable. Further, as the material used for forming the sodium-free layer, it is preferable to apply a material containing no sodium at all.

Further, the "sodium-containing layer" in the present invention means that the content of sodium with respect to the total mass of the sodium-containing layer is 1.0% by mass or more, preferably in the range of 1.0 to 20% by mass.

The term "superhydrophilic film" as used in the present invention means that the contact angle between the standard liquid (pure water) and the water contact angle control layer, which is the uppermost layer, is measured in accordance with the method specified by JIS R3257. In addition, the case where the water contact angle is 20 ° or less is defined as "superhydrophilic film" in the present invention, and is preferably 15 ° or less, more preferably 10 ° or less.

<< Specific components and components of superhydrophilic membrane >>
Hereinafter, the specific structure of the superhydrophilic membrane of the present invention and the details of its components will be described.

[Embodiment 1]
FIG. 3 is a cross-sectional view showing an example of a typical basic configuration of the superhydrophilic membrane of the present invention (Embodiment 1).

The superhydrophilic membrane of the present invention is characterized by having at least one sodium-containing layer on the substrate and a water contact angle control layer on the outermost surface side of the sodium-containing layer.

In the superhydrophilic film 1 shown in FIG. 3, a first reflectance adjusting layer unit 5 composed of a plurality of layers for controlling the light reflectance of the superhydrophilic film is formed on the substrate 2, and then on the first reflectance adjusting layer unit 5. , The sodium-containing layer 3 according to the present invention is formed, and the water contact angle control layer 4 according to the present invention is provided on the sodium-containing layer 3 as the outermost layer.

Hereinafter, details of each component constituting the superhydrophilic membrane shown in FIG. 3 will be described.

(Sodium-containing layer)
Specifically, the sodium-containing layer according to the present invention contains SiO ₂ as a main component and contains sodium as an element having an electronegativity smaller than Si. More specifically, sodium is 1.0 to 1.0 to It is preferably contained in the range of 20% by mass.

_{Regarding the durability (maintenance of hydrophilicity) of the SiO 2-} containing layer in a high-temperature and high-humidity (85 ° C., 85% RH) environment, the sodium-containing layer according to the present invention is sodium as an element having an electronegativity smaller than Si. By containing the above, the hydrophilic function is further improved, and a superhydrophilic film having a low water contact angle can be formed. Compared with the case of pure SiO _{2 , it is considered that SiO 2} incorporating a sodium element develops polarity in the arrangement of electrons, and this is considered to be compatible with _{H 2 O, which is a polar molecule.} That is, the electronegativity difference between the sodium element and O is larger than the electronegativity difference between Si and O, and an electrical bias occurs. It is presumed that the content of this sodium element is best in the range of 1.0 to 20% by mass, which causes an electrical bias, attracts water which is a polar molecule, and can obtain superhydrophilicity. Na ₂ O is inter alia a sodium oxide, melting point since relatively close to the melting point of SiO _2, there is SiO ₂ and simultaneously formed as likely benefit as a mixed vapor deposition material. There is little deviation in terms of the composition ratio of the vapor-filmed film.

In addition, when sodium is contained, NaOH derived from sodium is deliquescent, so it has the property of taking in water from the external environment and trying to become an aqueous solution, and is hydrophilic to take in water in a high temperature and high humidity environment. It is presumed that it can be maintained for a long period of time.

The material for forming the sodium-containing layer according to the present invention is not particularly limited. For example, as a commercially available product, SiO _{2- Na 2} O (Na content: 5% by mass, 10% by mass) manufactured by Toyoshima Seisakusho Co., Ltd. Etc. can be applied.
It is also possible to prepare a target mixed with sodium and form a sodium-containing layer by a sputtering method.

The layer thickness of the sodium-containing layer according to the present invention is preferably in the range of 1 to 500 nm, more preferably in the range of 1 to 100 nm, and further preferably in the range of 1 to 10 nm. When the layer thickness of the sodium-containing layer is 1 nm or more, a sodium component for obtaining desired high-temperature and high-humidity resistance can be imparted, and when it is 500 nm or less, the occurrence of haze can be suppressed.

The method for forming the sodium-containing layer according to the present invention is not particularly limited, but it is preferably formed by a dry film forming method, and more preferably, it is formed by a vapor deposition method under the condition that the amount of gas introduced is 5 sccm or more. It is preferable to form a film.

(Water contact angle control layer)
More specifically, the water contact angle control layer according to the present invention is formed as a sodium-free layer to move sodium from the sodium-containing layer located in the lower layer to the surface portion. In particular, a superhydrophilic film capable of improving heat cycle resistance and exhibiting excellent high-temperature and high-humidity resistance due to the sodium-containing layer can be obtained.

As described above, the "water contact angle control layer" according to the present invention has a function of controlling the water contact angle of the superhydrophilic membrane within a predetermined range in order to develop the heat cycle resistance of the superhydrophilic membrane. Refers to a layer having. The water contact angle control layer may have various purposes and functions in addition to the above functions as long as the effects of the present invention are not impaired. Specifically, "high temperature environment (treatment at 65 ° C for 4 hours) → temperature lowering to -15 ° C at 1 ° C / 1 minute → ultra-low temperature environment (treatment at -15 ° C for 4 hours) → 65 ° C at 1 ° C / minute. The water contact angle after repeating this for 6 cycles is maintained at 20 ° or less, and the water contact angle A after the heat cycle treatment is not yet set. It is defined as a layer having a characteristic that the change width (rise width) of the water contact angle is within + 20 ° with respect to the water contact angle B of the treated superhydrophilic membrane.

The water contact angle control layer according to the present invention is preferably a sodium-free layer. The sodium-free layer as used in the present invention means that the content of sodium with respect to the total mass of the sodium-free layer is less than 1.0% by mass, preferably 0.1% by mass or less including 0. In particular, it is preferably 0% by mass that does not contain sodium at all. Further, as the material used for forming the sodium-free layer, it is preferable to apply a material containing no sodium at all.
In the present invention, as a method for measuring the sodium content in the water contact angle control layer according to the present invention, a conventionally known method for analyzing elemental components can be applied to obtain the sodium content.
For example, since the layer thickness of the water contact angle control layer is extremely thin, one method is to measure the sodium content with a thickness of about 200 nm in the same manner as the method of forming the water contact angle control layer on the substrate. A single layer of the water contact angle control layer for use is formed, and this is used as a sample for measuring the sodium content in the water contact angle control layer, and the sodium content can be measured by the XPS composition analysis shown below.
<XPS composition analysis>
-Device name: X-ray photoelectron spectroscopy analyzer (XPS)
-Device model: Quantera SXM
・ Equipment manufacturer: ULVAC-PHI ・ Measurement conditions: X-ray source = monochromatic AlKα ray 25W-15kV
・ Vacuum degree: 5.0 × ^10-8 Pa
As another method, after forming a water contact angle control layer on a silicon substrate with a predetermined layer thickness, the sodium content can be measured by XPS composition analysis in the same manner as described above.

In the present invention, in the design of the water contact angle control layer, as a result of studying a constituent material capable of exhibiting the above effect, the water contact angle control layer is a material that does not impair the hydrophilicity of the sodium-containing layer. However, it is necessary to use a material that can suppress the movement of sodium to the surface with a thin layer thickness, and such a material contains at least one element selected from magnesium, calcium, cerium and phosphorus. Is preferable.

The layer thickness of the water contact angle control layer according to the present invention is preferably in the range of 0.1 to 50 nm. From the viewpoint of achieving both high temperature and high humidity resistance and heat cycle resistance in a harsh environment, it is not essential that the sodium component that realizes superhydrophilicity is present on the outermost surface, and the depth is 50 nm from the outermost surface. By being present in the following regions, high temperature and high humidity resistance can be exhibited. By providing a thin water contact angle control layer, specifically a non-sodium-containing layer, on the sodium-containing layer, diffusion of the sodium component to the outermost layer can be prevented, and the high-temperature and high-humidity resistance of the sodium-containing layer can be prevented. At the same time, it is possible to obtain a highly durable superhydrophilic film that is strong even under severe heat cycle conditions.

The material for forming the water contact angle control layer according to the present invention is not particularly limited as long as it does not contain a sodium component, and for example, it contains at least one element selected from magnesium, calcium, cerium and phosphorus, or two or more kinds thereof. The material to be applied can be applied.

Further, as a material for forming the water contact angle control layer, it can be obtained as a commercially available product, and as a typical material, a trade name: HP-3 manufactured by Canon Optron Co., Ltd. can be mentioned. The composition of HP-3 is C: 13.9 atom number%, O: 60.5 atom number%, P: 15.4 atom number%, Ca: 5.0 atom number%, Ce: 5.3 atom number. %.

The layer thickness of the water contact angle control layer according to the present invention is preferably in the range of 0.1 to 50 nm, more preferably in the range of 0.5 to 10 nm, and further preferably in the range of 1 to 10 nm. Inside. When the layer thickness of the water contact angle control layer is 0.1 nm or more, it is possible to prevent the diffusion of sodium from the sodium-containing layer located in the lower layer portion to the surface layer portion, and it is possible to obtain good heat cycle resistance. Further, if it is 50 nm or less, the effect of high temperature / high humidity resistance and the ability to lower the water contact angle of the sodium-containing layer located in the lower layer are not impaired.

The method for forming the water contact angle control layer according to the present invention is not particularly limited, but it is preferably formed by a dry film forming method, and more preferably, a vapor deposition method is used and the gas introduction amount is 5 sccm or more. It is preferable to form a film with.

(Laminated structure of sodium-containing layer and water contact angle control layer)
In the superhydrophilic membrane of the present invention, it is preferable that one or more water contact angle control layer units U composed of a sodium-containing layer and a water contact angle control layer are laminated, and more preferably described later. It is preferable that the three units as illustrated in FIGS. 8, 9 and 14 are laminated.

(Method of forming a film between the sodium-containing layer and the water contact angle control layer)
In the present invention, the film forming method of the sodium-containing layer and the water contact angle control layer is not particularly limited and may be a wet method or a dry method, but a dry method is preferable.

Examples of the dry method applicable to the present invention include a vacuum vapor deposition method, an ion beam deposition method, an ion plating method, and the like, and in the sputtering system, a sputtering method, an ion beam sputtering method, a magnetron sputtering method, and the like. The assisted vapor deposition method (hereinafter, also referred to as "IAD" in the present invention) or the sputtering method is preferable.

(substrate)
The substrate that can be applied to the formation of the superhydrophilic film of the present invention is not particularly limited, and examples thereof include resins such as glass, polycarbonate resin, and cycloolefin resin, and an in-vehicle lens is preferable.

(1st reflectance adjustment layer unit)
In the present invention, from the viewpoint of controlling the light reflectance of the superhydrophilic film, at least one reflectance adjusting layer unit is provided between the substrate and the sodium-containing layer according to the present invention, and the wavelength is within the range of 450 to 780 nm. It is preferable to control the average light reflectance in the above to 3.0% or less.

FIG. 4 is a cross-sectional view showing an example of a specific configuration of the first reflectance adjusting layer unit 5 described in FIG.

The configuration example of the first reflectance adjusting layer unit 5 shown in FIG. 4 is composed of the following first low refractive index layer 11A, high refractive index layer 12, second low refractive index layer 11B, and photocatalyst layer 13.

1) First low refractive index layer 11A: constituent material = SiO ₂ , layer thickness = 22 mn
2) High refractive index layer 12: constituent material = Ta ₂ O ₅ , layer thickness = 22 nm
3) Second low refractive index layer 11B: constituent material = SiO ₂ , layer thickness = 29 mn
4) Photocatalyst layer 13: constituent material = TiO ₂ , layer thickness = 112 nm
Next, the details of each component of the first reflectance adjusting layer unit will be described.

<First low refractive index layer 11A and second low refractive index layer 11B>
The first low refractive index layer and the second low refractive index layer according to the present invention are made of a material having a refractive index of less than 1.7, and in the present invention, the layer may contain _{SiO 2 as a main component.} preferable. However, it is also preferable to contain other metal oxides, and it is also preferable from the viewpoint of light reflectance that it is a mixture of _{SiO 2} and a part of Al ₂ O _{3 or Mg F 2.}

<High refractive index layer 12>
The high refractive index layer according to the present invention is composed of a material having a refractive index of 1.7 or more, for example, a mixture of Ta oxide and Ti oxide, Ti oxide, Ta oxide, and the like. It is preferably a mixture of La oxide and Ti oxide. The metal oxide used for the high refractive index layer preferably has a refractive index of 1.9 or more. In the present invention, _{it is preferably Ta 2} O ₅ or TiO ₂ , and more preferably Ta ₂ O ₅ .

In the present invention, the thickness of the first reflectance adjusting layer unit composed of the high refractive index layer and the low refractive index layer is not particularly limited, but may be 500 nm or less from the viewpoint of antireflection performance. It is preferably and more preferably in the range of 50 to 500 nm. When the thickness is 50 nm or more, the optical characteristics of antireflection can be exhibited, and when the thickness is 500 nm or less, the error sensitivity is lowered and the good quality ratio of the spectral characteristics of the lens can be improved.

<Photocatalyst layer 13>
In the first reflectance adjusting layer unit 5 according to the present invention, it is preferable to provide a photocatalyst layer having a photocatalytic function as the outermost layer.

_{The photocatalytic layer according to the present invention is preferably composed of TiO 2} as a metal oxide having a photocatalytic function, has a high refractive index, and is preferable in that the light reflectance of the dielectric multilayer film can be reduced. ..

The "photocatalytic function" in the present invention means the organic matter decomposition effect by the photocatalyst in the present invention. This is because when the photocatalytic TiO ₂ is irradiated with ultraviolet light, active oxygen and hydroxyl radicals (.OH radicals) are generated after electrons are emitted, and organic substances are decomposed by the strong oxidizing power of the active oxygen and hydroxyl radicals (.OH radicals). be. _{By adding a functional layer containing TiO 2} to the dielectric multilayer film of the present invention, it is possible to prevent organic substances and the like adhering to the optical member from contaminating the optical system as stains.

Whether or not it has a photocatalytic effect is determined by, for example, in an environment of 20 ° C. and 80% RH, a sample colored with a pen is irradiated with ultraviolet light with an integrated light amount of 20 J, and the color change of the pen is evaluated stepwise. You can judge by doing. As a specific photocatalyst performance test method, for self-cleaning by ultraviolet light irradiation, for example, a methylene blue decomposition method (ISO 10678 (2010)) and a resazurin ink decomposition method (ISO 21066 (2018)) can be mentioned.

In the present invention, as the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer, at least one high refractive index layer, and a low refractive index layer on the substrate. A second reflectance adjusting layer unit composed of a high refractive index layer and a sodium-containing layer is provided in this order, and the layer farthest from the substrate of the first reflectance adjusting layer unit is a metal having a photocatalytic function. After forming a superhydrophilic film having a structure of a photocatalyst layer containing an oxide, the structure may have pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and expose the surface of the photocatalyst layer. It is preferable in that a photocatalytic effect can be exhibited.

[Embodiment 2]
FIG. 5 is another example of the basic configuration of the superhydrophilic film of the present invention, and is a cross-sectional view showing a configuration in which a second reflectance constituent layer unit 6 is further formed with respect to the configuration shown in FIG. 3 (Embodiment 2). ).

Similar to the first embodiment (FIG. 3), the superhydrophilic film 1 shown in FIG. 5 forms a first reflectance adjusting layer unit 5 on the substrate 2 and is in water contact with the first reflectance adjusting layer unit 5. A second reflectance adjusting layer unit 6 for controlling the reflectance is provided between the angle control layer unit U and the angle control layer unit U.

FIG. 6 shows a specific configuration example 1 of the second reflectance adjusting layer unit 6.

In the configuration example 1 of the second reflectance adjusting layer unit 6 shown in FIG. 6, an example of a configuration in which the following constituent layers (6 layers) are laminated from the lower portion (substrate side) is shown.

1) Low refractive index layer 7: constituent material = SiO ₂ , layer thickness = 14 mn
2) Sodium-containing layer 3A: constituent material = SiO _2- Na ₂ O, layer thickness = 24 nm
3) High refractive index layer 8: constituent material = TiO ₂ , layer thickness = 2 mn
4) Sodium-containing layer 3A: constituent material = SiO _2- Na ₂ O, layer thickness = 11 nm
5) High refractive index layer 8: constituent material = TiO ₂ , layer thickness = 2 mn
6) Sodium-containing layer 3A: constituent material = SiO _2- Na ₂ O, layer thickness = 5 nm
By providing the second reflectance adjusting layer unit 6 composed of the above configuration example 1 between the first reflectance adjusting layer unit 5 and the water contact angle control layer unit U, the average light reflectance of the superhydrophilic film is desired. Conditions can be controlled, for example, 3.0% or less. In addition, by arranging the sodium-containing layer 3A containing sodium in the lower layer portion of the sodium-containing layer 3 constituting the water contact angle control layer unit U, the sodium-containing layer 3 contains the sodium-containing layer 3 in a high-temperature and high-humidity environment. It is possible to suppress the diffusion of the sodium component into the lower layer and prevent the deterioration of high temperature and high humidity resistance.

FIG. 7 shows a configuration example 2 as another specific configuration of the second reflectance adjusting layer unit 6.

In the configuration example 2 shown in FIG. 7, the second reflectance adjusting layer unit 6 is divided into two units, a second reflectance adjusting layer unit 6A and a second reflectance adjusting layer unit 6B, with respect to the above configuration example 1. An example of the configuration is shown. In the second reflectance adjusting layer unit 6A and the second reflectance adjusting layer unit 6B, the sodium concentration in the sodium-containing layers 3A and 3B composed _{of SiO 2-} Na _{2 O, respectively, is changed.}

The specific configurations of the second reflectance adjusting layer unit 6A and the second reflectance adjusting layer unit 6B shown in FIG. 7 from the substrate side are shown below.

<Second reflectance adjustment layer unit 6A>
1A) Sodium-containing layer 3A: constituent material = SiO _2- Na ₂ O (sodium content: 5% by mass), layer thickness = 5 nm
2A) Low refractive index layer 7: constituent material = SiO ₂ , layer thickness = 2 nm
The second reflectance adjusting layer unit 6A is formed by stacking four sets composed of the above 1A) and 2A).

<Second reflectance adjustment layer unit 6B>
1B) Sodium-containing layer 3B: constituent material = SiO _2- Na ₂ O (sodium content: 10% by mass), layer thickness = 5 nm
2B) Low refractive index layer 7: constituent material = SiO ₂ , layer thickness = 2 nm
The second reflectance adjusting layer unit 6B is formed by laminating three sets composed of the above 1B) and 2B).

By configuring the second reflectance adjusting layer unit as described above, the average light reflectance of the superhydrophilic film can be controlled to a desired condition, for example, 3.0% or less. In addition, by arranging the sodium-containing sodium-containing layers 3A and 3B in the lower layer portion of the sodium-containing layer 3 constituting the water contact angle control layer unit U, the sodium-containing layer 3 can be formed in a high temperature and high humidity environment. It is possible to suppress the diffusion of the contained sodium component into the lower layer and prevent the deterioration of the resistance to high temperature and high humidity. Further, _{by providing a low refractive index layer composed of SiO 2} between the sodium-containing layers, the sodium component crystallizes in the sodium-containing layer to prevent haze generation and light scattering as a superhydrophilic film. Can be done. Further, by lowering the sodium content on the substrate side, it is possible to prevent fogging or scattering of the coated surface in a high temperature and high humidity environment.

[Embodiment 3]
Specific configuration examples of superhydrophilic membranes other than those described above will be described.

FIG. 8 is a cross-sectional view showing another specific configuration of the superhydrophilic membrane of the present invention, showing a configuration in which three water contact angle control layer units U are laminated with respect to the configuration shown in FIG.

Specifically, as shown in FIG. 8, a first refractive index control layer unit 5 whose detailed configuration is described in FIG. 4 is formed on the substrate 2, and the detailed configuration thereof is shown in FIG. 6 on the first refractive index control layer unit 5. The second refractive index control layer unit 6 described above is laminated, and finally, three units of the water contact angle control layer unit U composed of the following sodium-containing layer 3 and the water contact angle control layer 4 are laminated thereto. The superhydrophilic film 1 is formed.

(Water contact angle control layer unit U)
1) Sodium-containing layer 3: Constituent material = SiO _2- Na ₂ O (sodium content: 10% by mass), layer thickness = 3 nm
2) Water contact angle control layer 4: Constituent material = HP-3 (above), layer thickness = 5 nm
[Embodiment 4: Addition of wear resistance improving layer]
The superhydrophilic film shown in FIG. 9 shows a structure in which an abrasion resistance improving layer 14 is further formed on the outermost layer of the superhydrophilic film having the structure described in FIG.

By forming the wear resistance improving layer on the outermost surface layer, excellent wear resistance can be obtained even after heat cycle treatment under severe conditions.

The wear resistance improving layer according to the present invention can be formed by, for example, a vacuum vapor deposition apparatus using _{SiO 2} as a film forming material for the wear resistance improving layer.

<< Manufacturing method of superhydrophilic membrane >>
Next, the details of the method for producing the superhydrophilic membrane of the present invention having the above structure will be described with reference to the drawings.

The method for producing the superhydrophilic film of the present invention includes a step of forming a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer on the substrate, and at least. A step of forming a second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer, and at least one layer of sodium and the sodium on the reflectance adjusting layer unit. It is a preferable form to have a step of forming a water contact angle control layer on the outermost surface side of the containing layer.

Further, it is a preferable form to form the water contact angle control layer as a sodium-free layer.

Further, the sodium content in the raw material used for forming the film of at least one layer of the sodium-containing layer is in the range of 1.0 to 20% by mass, or in the raw material used for forming the water contact angle control layer. The content of at least one element selected from magnesium, calcium, cerium and phosphorus is preferably in the range of 0.1 to 20% by mass.

In the method for producing a superhydrophilic film of the present invention, a water contact angle control layer unit composed of a sodium-containing layer and the water contact angle control layer, and a first reflection composed of a low refractive index layer and a high refractive index layer. The method for forming the second reflectance adjusting layer unit composed of the rate adjusting layer unit, the low refractive index layer, the high refractive index layer and the sodium-containing layer is not particularly limited, and for example, a dry method may be used even if it is a wet method. Although it may be a method, a dry method is preferable.

As the dry method (also referred to as dry film forming method) applicable to the present invention, the vapor deposition system includes a vacuum vapor deposition method, an ion beam vapor deposition method, an ion plating method, and the like, and the sputtering system includes a sputtering method and an ion beam sputtering method. , Magnetron sputtering method, etc. Among them, the ion assist deposit method (hereinafter, also referred to as "IAD" or "IAD method" in the present invention) or the sputtering method is preferable.

(Ion assist deposit method)
The IAD method is a method in which the high kinetic energy of ions acts during film formation to form a dense film and enhances the adhesion of the film. For example, the ion beam method is an ionized gas irradiated from an ion source. This is a method of accelerating the adherend material with molecules to form a film on the surface of the substrate.

FIG. 10 is a schematic view showing an example of a vacuum vapor deposition apparatus using the IAD method.

The vacuum vapor deposition apparatus 101 using the IAD method (hereinafter, also referred to as an IAD vapor deposition apparatus in the present invention) includes a dome 103 in the chamber 102, and the substrate 104 is arranged along the dome 103. The thin-film deposition source 105 is provided with an electron gun or a resistance heating device that evaporates the vapor-deposited substance, and the thin-film deposition material 106 is scattered from the thin-film deposition source 105 toward the substrate 4 and condenses and solidifies on the substrate 104. At that time, the ion beam 108 is irradiated from the IAD ion source 107 toward the substrate, and the high kinetic energy of the ions is applied during the film formation to form a dense film or enhance the adhesion of the film.

Here, the substrate 104 used in the present invention includes resins such as glass, polycarbonate resin, and cycloolefin resin, and is preferably an in-vehicle lens.

A plurality of thin-film deposition sources 105 are arranged at the bottom of the chamber 102. Here, one vapor deposition source is shown as the vapor deposition source 105, but the number of vapor deposition sources 105 may be plural. The film-forming material (deposited material) of the vapor-depositing source 105 is generated from the film-forming material 106 by an electron gun or resistance heating, and the film-forming material is scattered and adhered to the substrate 104 installed in the chamber 102. Low refractive index layer, high refractive index layer, photocatalyst layer, sodium-containing layer, water contact angle control layer, etc. (for example, SiO _{2 etc. which is a low refractive index material, Ta 2} O ₅ which is a high refractive index material , TiO _{2, etc., SiO 2-} Na ₂₀ which is a sodium-containing layer forming material, HP-3 which is a water contact angle control layer forming material, etc.) is formed on the substrate 104.

_{When forming a constituent layer containing SiO 2 according} to the present invention (for example, a low refractive index layer), a SiO ₂ target is arranged on the vapor deposition source 105 to form a film containing _{SiO 2 as a main component.} Is preferable. Further, in order to further improve the hydrophilic function, it is preferable to mix _{sodium with the SiO 2 as an element having an electronegativity smaller than Si.}

When adding a sodium element, a sodium-containing SiO ₂ target can be prepared, placed in a vapor deposition source, and directly vapor-deposited. Alternatively, the SiO ₂ target and the sodium target (Na ₂ O) can be arranged separately and the SiO ₂ and sodium can be vapor-deposited by co-depositing. In the present invention, it is preferable _{to prepare a sodium-containing SiO 2} target, place the target on a vapor deposition source, and directly vapor-deposit the target from the viewpoint of improving the sodium content accuracy.

As the sodium, it is preferable to use _{Na 2 O, and commercially available sodium can be used.}

Further, the chamber 102 is provided with a vacuum exhaust system (not shown), whereby the inside of the chamber 102 is evacuated. The degree of decompression in the chamber is usually in the range of 1 × 10 ^-4 to 1 × 10 ^-1 Pa, preferably 1 × 10 ^-3 to 1 × 10 ^-2 Pa.

The dome 103 holds at least one holder (not shown) for holding the substrate 104, and is also called a thin-film deposition umbrella. The dome 103 has an arcuate cross section, passes through the center of a chord connecting both ends of the arc, and has a rotationally symmetric shape that rotates with an axis perpendicular to the chord as a rotationally symmetric axis. As the dome 103 rotates about the axis, for example, at a constant speed, the substrate 104 held by the dome 103 via the holder revolves around the axis at a constant speed.

The dome 103 can hold a plurality of holders side by side in the radial direction of rotation (radial direction of revolution) and the direction of rotation (revolutionary direction). As a result, it is possible to simultaneously form a film on a plurality of substrates 104 held by a plurality of holders, and it is possible to improve the manufacturing efficiency of the laminate.

The IAD ion source 107 is a device that introduces argon gas or oxygen gas into the main body to ionize them and irradiates the ionized gas molecules (ion beam 108) toward the substrate 104. Argon gas and oxygen gas have positive charges accumulated on the substrate in order to prevent the phenomenon that the entire substrate is positively charged (so-called charge-up) due to the accumulation of positive ions emitted from the ion gun on the substrate. It is also used as a neutralizer that electrically neutralizes the gas.

As the ion source, Kaufmann type (filament), hollow cathode type, RF type, bucket type, duoplasmatron type and the like can be applied. By irradiating the substrate 104 with the above gas molecules from the IAD ion source 107, for example, molecules of the film-forming material evaporating from a plurality of evaporation sources can be pressed against the substrate 104, and a film having high adhesion and denseness can be formed on the substrate. A film can be formed on 104. Although the IAD ion source 107 is installed at the bottom of the chamber 102 so as to face the substrate 104, it may be installed at a position deviated from the facing axis.

In the IAD method, for example, an ion beam having an acceleration voltage of 100 to 2000 V and an ion beam having a current density of 1 to 120 μA / cm ² or an ion beam having an acceleration voltage of 500 to 1500 V and a current density of 1 to 120 μA / cm ² are used. Can be used. In the film forming step, the irradiation time of the ion beam can be set to, for example, 1 to 800 seconds, and the number of particles irradiated by the ion beam can be set, for example, 1 × 10 ^{13 to} 5 × 10 ¹⁷ pieces / cm ² . The ion beam used in the film forming step can be an oxygen ion beam, an argon ion beam, or an ion beam of a mixed gas of oxygen and argon. In the present invention, it is preferable to form a film under the condition that the amount of gas introduced is 5 sccm or more. For example, the amount of oxygen introduced is preferably in the range of 30 to 60 sccm. "SCCM" is an abbreviation for wavelength cc / min, and is ^{a unit indicating how many cc flowed per minute at 1 atm (atmospheric pressure 10 13} hPa) and 0 ° C. The monitor system (not shown) is a vacuum. It is a system that monitors the wavelength characteristics of the layer formed on the substrate 104 by monitoring the layer that evaporates from each vapor deposition source 105 during the film formation and adheres to itself. With this monitoring system, it is possible to grasp the optical characteristics (for example, spectral transmittance, light reflectance, optical layer thickness, etc.) of the layer formed on the substrate 104. The monitor system also includes a crystal layer thickness monitor, and can monitor the physical layer thickness of the layer formed on the substrate 104. This monitor system also functions as a control unit that controls ON / OFF switching of a plurality of evaporation sources 105, ON / OFF switching of the IAD ion source 7, and the like according to the monitoring result of the layer.

(Sputtering method)
For the film formation by the sputtering method, bipolar sputtering, magnetron sputtering, dual magnetron sputtering (DMS) using an intermediate frequency region, ion beam sputtering, ECR sputtering and the like can be used alone or in combination of two or more. Further, the target application method is appropriately selected according to the target type, and either DC (direct current) sputtering or RF (radio frequency) sputtering may be used.

The sputtering method may be multiple simultaneous simultaneous sputtering using a plurality of sputtering targets. Regarding the method for producing these sputtering targets and the method for producing a thin film using these sputtering targets, for example, JP-A-2000-160331, JP-A-2004-068109, and JP-A-2013-047361. Etc. can be referred to as appropriate.

<< Formation of pores >>
In the superhydrophilic film of the present invention, as the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer is provided on the substrate. A second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer is provided in this order, and the layer farthest from the substrate of the first reflectance adjusting layer unit is a photocatalyst. One of the preferred embodiments is to form a photocatalyst layer containing a functional metal oxide and have pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and expose the surface of the photocatalyst layer.

First, the manufacturing process flow for forming pores in the superhydrophilic membrane of the present invention will be described with reference to the drawings.

FIG. 11 is a flowchart showing an example of a step of manufacturing a superhydrophilic film and a step of forming pores. The present invention is not limited to the manufacturing method described below.

(Step S11)
A first reflectance adjusting layer unit 5 composed of a low refractive index layer, a high refractive index layer, and the like is formed on the substrate 2 by, for example, a dry film forming method.

(Step S12)
Further, a photocatalyst layer 13 is formed on the outermost surface layer of the first reflectance adjusting layer unit 5 by a dry film forming method.

(Step S13)
Next, on the photocatalyst layer 13 constituting the first reflectance adjusting layer unit 5, the second reflectance adjusting layer unit 6 composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer by a dry film forming method. To form. At this time, the second reflectance adjusting layer unit 6 may have a configuration in which a plurality of layers of the high refractive index layer 8 and the sodium-containing layer 3A are laminated as described with reference to FIG. As described above, the low refractive index layer 7 and the sodium-containing layers 3A and 3B may be laminated in a plurality of layers.

(Step S14)
Next, the sodium-containing layer 3 is formed on the second reflectance adjusting layer unit 6 by using, for example, a dry film forming method.

(Step S15)
Next, a water contact angle control layer 4, more preferably a layer containing no nutrium component, is formed on the sodium-containing layer 3 by using, for example, a dry film forming method to form a superhydrophilic film.

The steps S14 and S15 may be repeated to form a water contact angle control layer unit U by laminating a plurality of sets of units composed of a plurality of sodium-containing layers 3 / water contact angle control layers 4. can.

(Step S16)
Next, a mask is formed on the outermost layer of the superhydrophilic film. Examples of the mask include a metal mask composed of a metal portion and an exposed portion.

(Step S17)
Next, through the mask, the pores 10 are formed by etching from the surface side to the upper surface of the photocatalyst layer 13 from the outermost surface layer using an etching apparatus to expose the surface of the photocatalyst layer.

(Step S18)
Finally, by removing the mask formed on the surface, a superhydrophilic film having pores can be obtained.

Next, a specific configuration of the superhydrophilic membrane having pores will be described.

FIG. 12 is a cross-sectional view (embodiment 5) showing an example of a configuration in which pores are formed in the superhydrophilic membrane to expose the photocatalyst layer.

As shown in FIG. 12, a first reflectance adjusting layer unit 5 having a photocatalyst layer 13 on the uppermost layer is formed on the substrate 2 according to the above-described method for forming a superhydrophilic film, and then a second is formed on the first reflectance adjusting layer unit 5. The reflectance adjusting layer unit 6 is laminated, and the sodium-containing layer 3 and the water contact angle control layer 4 are laminated as the water contact angle control layer unit U on the reflectance adjusting layer unit 6 to form the superhydrophilic film 1 shown in FIG. do.

Then, according to the following method, pores 10 are formed by a reactive etching treatment or a physical etching treatment using a mask to penetrate from the outermost surface layer to the upper surface portion of the photocatalyst layer 13 and expose the surface of the photocatalyst layer 13.

By forming the pores having such a structure, an excellent photocatalytic function can be exhibited.

Hereinafter, the flow of producing pores according to the present invention will be described with reference to the drawings.

FIG. 13 is a production flow chart showing an example of a method of forming pores in a superhydrophilic membrane.

In step 1 of FIG. 13, the superhydrophilic membrane 1 having the structure described in FIG. 12 is prepared.

Next, in step 2, a metal mask 9 is formed on the surface of the water contact angle control layer 4, which is the uppermost layer. The metal mask 9 is composed of a metal portion and an exposed portion. The layer thickness of the metal mask 9 is in the range of 1 to 30 nm. Although it depends on the film forming conditions, for example, when the metal mask 9 is formed into a film so that the layer thickness is 2 nm by using a thin film deposition method, the metal mask 9 becomes particulate. Further, for example, when the metal mask 50 is formed into a film so that the layer thickness is 12 to 15 nm by using a thin-film deposition method, the metal mask 50 tends to have a leaf vein shape. Further, when a film is formed so that the layer thickness becomes 10 nm by using, for example, a sputtering method, the metal mask 50 tends to have a porous shape.

In the present invention, the metal mask 9 is formed of, for example, Ag, Al, or the like, and is particularly silver, and the film formation temperature is controlled within the range of 20 ° C. to 400 ° C. and the thickness is controlled within the range of 1 to 30 nm. It is preferable from the viewpoint of controlling the shape of the pores.

Next, in step 3, the etching apparatus E is used to penetrate from the outermost surface layer to the upper surface of the photocatalyst layer 13 by etching to form pores 10 that expose the surface of the photocatalyst layer.

As shown in step 3, for etching, a reactive dry etching using an etching apparatus E or an apparatus in which an etching gas is introduced into an IAD vapor deposition apparatus is used. In the pore forming step, for example, CHF ₃ , CF ₄ , COF _2, SF _{6, and the} like are used as the etching gas. As a result, a plurality of pores 10 are formed by etching from the outermost surface layer to the upper surface of the photocatalyst layer 13 with a predetermined size to expose the surface of the photocatalyst layer 13. That is, the constituent layer corresponding to the exposed portion of the metal mask 9 is etched to form the pores 10, and the surface of the photocatalyst layer 13 is partially exposed.

Finally, as step 4, the metal mask 9 is removed. Specifically, the metal mask 9 is removed by wet etching with a chemical such as acetic acid. Further, the metal mask 9 may be removed by dry etching using, for example, Ar or O _{2 as an etching gas.}

By the above steps, a superhydrophilic membrane 1 having a plurality of pores 10 can be obtained.

According to the method for producing a superhydrophilic film and the method for forming pores, after forming each constituent layer, a plurality of layers for penetrating from the outermost surface layer to the upper surface of the photocatalyst layer 13 to exhibit the photocatalytic function of the photocatalyst layer. By forming the pores 10, it is possible to achieve both superhydrophilicity and photocatalytic function.

<< Application field of superhydrophilic membrane: Optical member >>
The superhydrophilic film of the present invention is a superhydrophilic film having low light reflectance, hydrophilicity and photocatalytic properties, and also excellent in properties such as salt water resistance and scratch resistance. In the present invention, the superhydrophilic film of the present invention The optical member is preferably a lens, an antibacterial cover member, an antifungal coating member or a mirror, for example, an in-vehicle lens, a communication lens, or an endoscope. Antibacterial lenses for PCs and smartphones, hydrophilic members and antibacterial cover members, glasses, pottery such as toilets and tableware, antifungal coatings for baths and sinks, or building materials (window glass). Suitable.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

<< Preparation of superhydrophilic membrane >>
[Preparation of superhydrophilic membrane 1]
According to the following method, a superhydrophilic film 1 composed of the substrate 2 shown in FIG. 14, the first reflectance adjusting layer unit 5, the second reflectance adjusting layer unit 6, and the water contact angle control layer unit U was produced.

[Preparation of board]
As a substrate, a white plate glass substrate (refractive index: 1.523) manufactured by SCHOTT was prepared.

[Formation of First Reflectance Adjusting Layer Unit 5]
On a white plate glass substrate, by the following vacuum vapor deposition method, as shown in FIG. 14, from the substrate 2 side.
1) First low refractive index layer 11A (SiO ₂ , layer thickness: 22 nm),
2) High refractive index layer 12 (Ta ₂ O ₅ + TiO ₂ , 22 nm),
3) First low refractive index layer 11B (SiO ₂ , layer thickness: 29 nm),
4) Photocatalyst layer 13 (TiO ₂ , layer thickness: 112 nm)
Was sequentially laminated to form the first reflection adjusting layer unit 5.

(Film formation conditions / equipment used)
<Conditions in the chamber>
Heating temperature 370 ° C
Starting vacuum degree 5.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun <IAD ion source>
Syncron RF Ion Source NIS-175-3

(Formation of First Reflectance Adjusting Layer Unit 5)
<Formation of the first low refractive index layer 11A>
Film formation material for the first low refractive index layer 11A: SiO ₂ (Canon Optron trade name SiO ₂ )
The above substrate is installed in an IAD vacuum vapor deposition apparatus, SiO ₂ is loaded as a film forming material in the first evaporation source, vapor deposition is carried out at a film forming speed of 3 Å / sec, and the first low refractive index layer 11A having a layer thickness of 22 nm. Was formed.

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas was carried out _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm.

<Formation of high refractive index layer 12>
Film-forming material for the high-refractive index layer 12: Ta ₂ O ₅ (Canon Optron trade name OA-600)
The film-forming material is loaded into the second evaporation source of the IAD vacuum vapor deposition apparatus, vapor-deposited at a film-forming rate of 4 Å / sec, and a high-refractive index layer 12 having a layer thickness of 22 nm is formed on the first low-refractive index layer 11A. Formed.

The high refractive index layer 12 was formed by the IAD method in the same manner as described above under heating conditions of 370 ° C.

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas was carried out _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm. _{At this time, O 2} gas is introduced from the auto pressure controller (hereinafter, abbreviated as “APC”) so that the chamber pressure becomes 2 × 10 ^{-2 Pa by controlling the gas.}

<Formation of the second low refractive index layer 11B>
Film formation material for the second low refractive index layer 11B: SiO ₂ (Canon Optron trade name SiO ₂ )
The above substrate is installed in an IAD vacuum vapor deposition apparatus, SiO ₂ is loaded as a film forming material in the first evaporation source, vapor deposition is carried out at a film forming speed of 3 Å / sec, and a second low refractive index layer 11B having a layer thickness of 29 nm. Was formed.

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas was carried out _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm.

<Formation of photocatalyst layer 13>
Film-forming material of photocatalyst layer 13: TiO ₂ (Fuji Titanium Industry Co., Ltd. trade name TOP (Ti ₃ O ₅ ))
The substrate is installed in a vacuum vapor deposition apparatus, the film forming material is loaded into the third evaporation source, vapor deposition is carried out at a film forming rate of 2 Å / sec, and a photocatalyst having a thickness of 112 nm is deposited on the second low refractive index layer 11B. A layer was formed. The photocatalyst layer was similarly formed by the IAD method and heating conditions at 370 ° C.

IAD conditions, acceleration voltage 300 V, accelerating current 300 mA, suppressor voltage 1000V, neutralization current 600 mA, IAD introduced gas was carried out by _O 2 50 sccm, Ar gas 10 sccm, the neutral gas Ar10sccm conditions. At this time, gas was controlled and _{O 2} gas was introduced from the APC so that the ^{chamber pressure became 3 × 10 -2 Pa.}

[Formation of Second Reflectance Layering Unit 6]
On the first reflectance adjusting layer unit 5 produced above, a second reflectance adjusting layer unit 6A composed of eight layers and six layers on the second reflectance adjusting layer unit 6A composed of eight layers by the following vacuum vapor deposition method. The second reflectance adjusting layer unit 6B composed of the above was laminated to form the second reflectance layering unit 6.

1) Configuration of Second Reflectance Adjusting Layer Unit 6A The second reflectance adjusting layer unit 6A has a sodium-containing layer 3A (SiO _{2- Na 2} O (Na content: 5% by mass), layer thickness: 5 nm) / low. It was formed by laminating four sets of units having a refractive index layer 7 (SiO _{2, layer thickness: 2 nm).}

2) Configuration of Second Reflectance Adjusting Layer Unit 6B The second reflectance adjusting layer unit 6B has a sodium-containing layer 3B (SiO _{2- Na 2} O (Na content: 10% by mass), layer thickness: 5 nm) / low. Three sets of units having a refractive index layer 7 (SiO _2, layer thickness: 2 nm) were laminated to form the unit.

(Film formation conditions / equipment used)
<Conditions in the chamber>
Heating temperature 50 ° C
Starting vacuum degree 3.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun <IAD ion source>
Syncron RF Ion Source NIS-175-3

(Formation of the second reflectance adjusting layer unit 6A)
According to the following method, four sets of units composed of the sodium-containing layer 3A and the low refractive index layer 7 are laminated on the first reflectance adjusting layer unit 5 by the following method to form a second reflectance adjusting layer unit. 6A was formed.

<Formation of sodium-containing layer 3A>
Film formation material for sodium-containing layer 3A: Toyoshima Seisakusho Co., Ltd., trade name: SiO _{2- Na 2} O (Na content: 5% by mass)
The substrate formed up to the first reflectance adjusting layer unit 5 is installed in an IAD vacuum vapor deposition apparatus, and the film-forming material of the sodium-containing layer 3A is loaded into the first evaporation source and vapor-deposited at a film-forming rate of 3 Å / sec. A sodium-containing layer 3A having a layer thickness of 5 nm and a Na content of 5% by mass was formed.

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas is _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm, was carried out by heating conditions 50 ° C..

<Formation of low refractive index layer 7>
Film formation material for low refractive index layer: SiO ₂ (Canon Optron trade name SiO ₂ )
The above-mentioned base material was installed in an IAD vacuum vapor deposition apparatus, the film-forming material was loaded into a second evaporation source, and vapor deposition was performed at a film-forming rate of 3 Å / sec to form a low refractive index layer 7 having a layer thickness of 2 nm. ..

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas was carried out _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm. This was done under 50 ° C. heating conditions.

(Formation of the second reflectance adjusting layer unit 6B)
According to the following method, three sets of units composed of the sodium-containing layer 3B and the low refractive index layer 7 formed by the following method are laminated on the second reflectance adjusting layer unit 6A to form a second reflectance adjusting layer. Unit 6B was formed.

<Formation of sodium-containing layer 3B>
Film formation material for sodium-containing layer 3B: Toyoshima Seisakusho Co., Ltd., trade name: SiO _{2- Na 2} O (Na content: 10% by mass)
The substrate formed up to the second reflectance adjusting layer unit 6A was installed in an IAD vacuum vapor deposition apparatus, the film forming material was loaded into the first evaporation source, and the film was deposited at a film forming rate of 3 Å / sec, and the layer thickness was 5 nm. A sodium-containing layer 3B having a Na content of 10% by mass was formed.

IAD conditions, an acceleration voltage 1000V, acceleration current 1000 mA, suppressor voltage 500V, neutralization current 1500 mA, IAD introduced gas is _O 2 50 sccm, Ar gas 0 sccm, under the condition of the neutral gas Ar10sccm, was carried out by heating conditions 50 ° C..

<Formation of low refractive index layer 7>
A low refractive index layer 7 having a layer thickness of 2 nm was formed in the same manner as used for forming the second reflectance adjusting layer unit 6A.

[Formation of water contact angle control layer unit U]
On the second reflectance adjusting layer unit 6 formed above, a sodium-containing layer 3B (SiO _{2- Na 2} O (Na content: 10% by mass)), a layer, as shown in FIG. 14, by the following vacuum vapor deposition method. Three sets of units of thickness: 3 nm) / water contact angle control layer 4 (forming material: HP-3 _, layer thickness: 5 nm) are laminated to form a water contact angle control layer unit U to prepare a superhydrophilic film 1. bottom.

(Film formation conditions / equipment used)
<Conditions in the chamber>
Heating temperature 50 ° C
Starting vacuum degree 3.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun <IAD ion source>
Syncron RF Ion Source NIS-175-3
(Formation of sodium-containing layer 3B)
The sodium-containing layer 3B having a layer thickness of 3 nm was formed in the same manner as the formation of the sodium-containing layer 3B used for forming the second reflectance adjusting layer unit 6B.

(Formation of water contact angle suppressing layer 4)
Film-forming material for the water contact angle control layer 4: HP-3 (Canon Optron trade name HP-3)
The substrate formed up to the second reflectance adjusting layer unit 6 is installed in the IAD vacuum vapor deposition apparatus, the film forming material of the water contact angle control layer 4 is loaded into the first evaporation source, and the formed sodium-containing layer 3B On top of this, vapor deposition was performed at a film formation rate of 2 Å / sec to form a water contact angle suppressing layer 4.

The composition of HP-3 is C: 13.9 atom number%, O: 60.5 atom number%, P: 15.4 atom number%, Ca: 5.0 atom number%, Ce: 5.3 atom number. %.

(Measurement of average light reflectance)
The average light reflectance of the prepared superhydrophilic film in the wavelength range of 450 to 780 nm was measured using USPM-RU, which is a microscopic spectral reflectance measuring device manufactured by Olympus Corporation, and found to be 3.1%. there were.

(Measurement of sodium content of water contact angle control layer)
In the production of the superhydrophilic film 1, a single layer of the water contact angle control layer 4 for measuring the sodium content having a layer thickness of 5 nm is formed on the silicon substrate in the same manner as in the method of forming the water contact angle control layer 4 on the substrate. As a result of measuring the sodium content by the XPS composition analysis shown below, it was confirmed that the sodium content in the water contact angle control layer 4 was less than 0.01% by mass and almost not contained. "None" was displayed in the "Sodium content" column of Table I.

<XPS composition analysis>
-Device name: X-ray photoelectron spectroscopy analyzer (XPS)
-Device model: Quantera SXM
・ Equipment manufacturer: ULVAC-PHI ・ Measurement conditions: X-ray source = monochromatic AlKα ray 25W-15kV
・ Vacuum degree: 5.0 × ^10-8 Pa

[Preparation of superhydrophilic membrane 2]
In the production of the superhydrophilic film 1, the same applies except that the layer thickness of the sodium-containing layer 3B constituting the water contact angle control layer unit U was changed to 0.05 nm and the number of laminated units was changed from 3 to 1. , A superhydrophilic film 2 having a light reflectance of 2.4% was prepared.

In the production of the superhydrophilic film 2, the thickness of each layer constituting the second reflectance adjusting layer unit is adjusted in response to the change in the light reflectance due to the change in the layer thickness of the sodium-containing layer 3B and the change in the number of units. It was adjusted as appropriate so that the light reflectance was 2.2%.

[Preparation of superhydrophilic membrane 3]
In the preparation of the superhydrophilic film 1, the superhydrophilic film 3 having a light reflectance of 2.2% was produced in the same manner except that the number of units of the water contact angle control layer unit U was changed from 3 to 1.

In the production of the superhydrophilic film 3, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the number of units, and the light reflectance is 2. Adjusted to 2%.

[Preparation of superhydrophilic membrane 4]
In the preparation of the superhydrophilic film 2, the superhydrophilic film 4 having a light reflectance of 10.1% is the same except that the layer thickness of the sodium-containing layer 3B constituting the water contact angle control layer unit U is changed to 500 nm. Was produced.

In the production of the superhydrophilic film 4, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the layer thickness of the sodium-containing layer 3B. The reflectance was adjusted to 10.1%.

[Preparation of superhydrophilic membrane 5]
In the production of the superhydrophilic film 3, the light reflectance was 2.4% in the same manner except that the sodium content of the sodium-containing layer 3B constituting the water contact angle control layer unit U was changed to 0.05% by mass. The superhydrophilic membrane 5 of the above was prepared.

In the production of the superhydrophilic film 5, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the sodium content of the sodium-containing layer 3B. , The light reflectance was adjusted to 2.4%.

[Preparation of superhydrophilic membrane 6]
In the preparation of the superhydrophilic film 3, the superhydrophilicity having a light reflectance of 2.2 is the same except that the sodium content of the sodium-containing layer 3B constituting the water contact angle control layer unit U is changed to 25% by mass. A film 6 was produced.

In the production of the superhydrophilic film 6, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the sodium content of the sodium-containing layer 3B. , The light reflectance was adjusted to 2.2%.

[Preparation of superhydrophilic membrane 7]
In the production of the superhydrophilic film 3, the light reflectance is 2.1% in the same manner except that the layer thickness of the water contact angle control layer 4 constituting the water contact angle control layer unit U is changed to 0.05 nm. A superhydrophilic membrane 7 was prepared.

In the production of the superhydrophilic film 7, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the layer thickness of the water contact angle control layer 4. Then, the light reflectance was adjusted to 2.1%.

[Preparation of superhydrophilic membrane 8]
In the production of the superhydrophilic film 3, the superhydrophilicity having a light reflectance of 6.2% is the same except that the layer thickness of the water contact angle control layer 4 constituting the water contact angle control layer unit U is changed to 60 nm. Membrane 8 was prepared.

In the production of the superhydrophilic film 8, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to the change in the light reflectance due to the change in the layer thickness of the water contact angle control layer 4. Then, the light reflectance was adjusted to 6.2%.

[Preparation of superhydrophilic membrane 9]
In the production of the superhydrophilic film 3, the light reflectance is more than 2.4% in the same manner except that the constituent material of the water contact angle control layer 4 constituting the water contact angle control layer unit U is _{changed to SiO 2.} A hydrophilic film 9 was prepared.

In the production of the superhydrophilic film 9, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to a change in the light reflectance due to a change in the constituent material of the water contact angle control layer 4. Then, the light reflectance was adjusted to 2.4%.

[Preparation of superhydrophilic membrane 10]
In the production of the superhydrophilic film 3, the light reflectance is more than 2.5% in the same manner except that the constituent material of the water contact angle control layer 4 constituting the water contact angle control layer unit U is _{changed to TiO 2.} A hydrophilic film 10 was prepared.

In the production of the superhydrophilic film 10, the film thickness of each layer constituting the second reflectance adjusting layer unit is appropriately changed in response to a change in the light reflectance due to a change in the constituent material of the water contact angle control layer 4. Then, the light reflectance was adjusted to 2.5%.

[Preparation of superhydrophilic membrane 11]
In the production of the superhydrophilic film 3, the superhydrophilic film 11 having a light reflectance of 1.5 is formed in the same manner except that the friction resistance improving layer is formed on the water contact angle control layer unit U according to the following method. Made.

(Film formation conditions and equipment used for the abrasion resistance improving layer)
<Conditions in the chamber>
Heating temperature 50 ° C
Starting vacuum degree 3.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun <IAD ion source>
(Formation of abrasion resistance improving layer)
Film-forming material for the wear resistance improving layer: SiO ₂ (Canon Optron trade name SiO ₂ )
The superhydrophilic film 3 was installed in an IAD vacuum vapor deposition apparatus, the above-mentioned film forming material was loaded into a third evaporation source, and vapor deposition was performed at a film forming rate of 3 Å / sec to form a wear resistance improving layer.

IAD was not used and it was carried out under 50 ° C. heating conditions. At this time, gas is controlled and _{O 2} gas is introduced from the APC so that the ^{chamber pressure becomes 3 × 10 -2 Pa.}

[Preparation of superhydrophilic membrane 12]
In the preparation of the superhydrophilic film 11, the superhydrophilic film 12 was prepared in the same manner except that the photocatalyst layer 13 was etched until the photocatalyst layer 13 was exposed according to the method shown in FIG. 12 to form pores 10. Was produced.

[Formation of pores]
After forming the water contact angle control layer 4, according to the pore forming method shown in FIG. 12, Ag as the mask material, the vapor deposition method as the mask film forming 9, the mask thickness 12 nm, the etching gas CHF ₃ , and the etching time 60 sec. Under the conditions of (1), the pores 10 shown in FIG. 12 were formed to prepare a superhydrophilic film 12 having pores.

The detailed pore formation conditions are as follows.

In step 2 described in FIG. 13, a film forming apparatus (BES-1300) (manufactured by Syncron Co., Ltd.) was used for Ag film formation, and the film was formed under the following conditions to form an Ag mask.

Heating temperature 25 ° C
Starting vacuum 1.33 × 10 ^-3 Pa
Film formation rate 7 Å / sec
In step 3 described in FIG. 13, an etching apparatus (CE-300I) (manufactured by ULVAC, Inc.) was used for etching, and a film was formed under the following conditions. The width length and depth of the pores were adjusted by changing the etching time.

Antenna RF 400W
Bias RF 38W
APC pressure 0.5Pa
CHF ₃ flow rate 20 sccm
Etching time 60 sec
Then, as step 4 in FIG. 13, the silver mask was removed using a chemical.

[Preparation of superhydrophilic membrane 13]
In the preparation of the superhydrophilic film 12, the superhydrophilicity having a light reflectance of 1.5 is the same except that the sodium content of the sodium-containing layer 3B constituting the water contact angle control layer unit U is changed to 5% by mass. A film 13 was produced.

[Preparation of superhydrophilic membrane 14: comparative example]
In the preparation of the superhydrophilic film 1, the first reflectance adjusting layer unit 5 was formed in the same manner. _{Next, a low refractive index layer 11A composed of a SiO 2} film having a layer thickness of 15 nm is formed on the first reflectance adjusting layer unit 5 by a vacuum vapor deposition method according to the following method, and the configuration shown in FIG. A superhydrophilic membrane 14 made of the above was prepared.

(Film formation conditions)
<Conditions in the chamber>
Heating temperature 200 ° C
Starting vacuum degree 5.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun (formation of low refractive index layer 11A)
Film formation material for low refractive index layer: SiO ₂ (Canon Optron trade name: SiO ₂ )
The substrate formed up to the first reflectance adjusting layer unit 5 is installed in an IAD vacuum vapor deposition apparatus, the film forming material is loaded into the first evaporation source, and the film is deposited at a film forming rate of 0.5 Å / sec. A low refractive index layer 11A having a base thickness of 15 nm was formed.

At the time of film formation, gas control is performed without using the IAD condition, _{and O 2} gas is introduced from the APC so that ^{the chamber pressure becomes 2 × 10 -2 Pa.}

[Preparation of superhydrophilic membrane 15: comparative example]
In the preparation of the superhydrophilic film 1, the first reflectance adjusting layer unit 5 was formed in the same manner. Next, a water contact angle control layer 4 composed of HP-3 having a layer thickness of 100 nm was formed on the first reflectance adjusting layer unit 5 by a vacuum vapor deposition method according to the following method, and is shown in FIG. A superhydrophilic membrane 15 having a composition was produced.

(Film formation conditions)
<Conditions in the chamber>
Heating temperature 50 ° C
Starting vacuum degree 5.0 × 10 ^-3 Pa
<Evaporation source of film-forming material>
Electron gun (formation of water contact angle control layer 4)
Film-forming material for the water contact angle control layer 4: HP-3 (Canon Optron trade name HP-3)
The substrate formed up to the first reflectance adjusting layer unit 5 is installed in an IAD vacuum vapor deposition apparatus, the first evaporation source is loaded with the film forming material of the water contact angle control layer 4, and the film forming rate is 2 Å /. The water contact angle suppressing layer 4 was formed by vapor deposition in sec. At this time, the IAD condition was not used.

The composition of HP-3 is C: 13.9 atom number%, O: 60.5 atom number%, P: 15.4 atom number%, Ca: 5.0 atom number%, Ce: 5.3 atom number. %.

[Preparation of superhydrophilic membrane 16: comparative example]
In the preparation of the superhydrophilic film 1, the first reflectance adjusting layer unit 5 was formed in the same manner. Next, only the sodium-containing layer was formed on the first reflectance adjusting layer unit 5 by a vacuum vapor deposition method according to the following method to prepare a superhydrophilic film 16.

<Formation of sodium-containing layer>
Sodium-containing layer film-forming material: Toyoshima Seisakusho Co., Ltd., trade name: SiO _{2- Na 2} O (Na content: 10% by mass)
The substrate formed up to the first reflectance adjusting layer unit 5 is installed in an IAD vacuum vapor deposition apparatus, the film forming material is loaded into the first evaporation source, and the film is deposited at a film forming rate of 3 Å / sec, and the layer thickness is 90 nm. A sodium-containing layer having a Na content of 10% by mass was formed.

<< Evaluation of superhydrophilic membrane >>
The performance of each of the prepared superhydrophilic membranes was evaluated according to the method described below.

[Measurement of contact angle A: contact angle immediately after fabrication]
The contact angle A of each of the prepared superhydrophilic membranes was measured according to the following method.

Using the contact angle measuring device G-1 manufactured by Elma, 10 μL of pure water was dropped on the surface of the superhydrophilic membrane in an environment of 23 ° C. and 50% RH, and the static contact angle 5 seconds after the dropping was measured. This was designated as the contact angle A.

Next, the measured contact angle A was ranked according to the following criteria.

⊚: Contact angle A is less than 5 ° 〇: Contact angle A is 5 ° or more and less than 10 ° Δ: Contact angle A is 10 ° or more and 20 ° or less ×: Contact angle A is , Over 20 °

[Evaluation of heat cycle resistance]
(Measurement of contact angle B: contact angle after heat cycle processing)
For each superhydrophilic membrane, after maintaining at 65 ° C. for 4 hours as a high temperature environment, lowering the temperature from 65 ° C. to -15 ° C. under the condition of 1 ° C./1 minute, and then maintaining at -15 ° C. for 4 hours as a cryogenic environment. The temperature was raised to 65 ° C. under the condition of 1 ° C./1 minute, and this was set as one cycle and repeated from 0 to 6 cycles.
Next, the contact angle B was measured for each cycle by the following method, the number of cycles capable of maintaining the contact angle B of 15 ° or less was determined, and the heat cycle resistance was evaluated according to the following criteria.

The contact angle B is measured by using a contact angle measuring device G-1 manufactured by Elma Co., Ltd., in an environment of 23 ° C. and 50% RH, 10 μL of pure water is dropped on the surface of the superhydrophilic membrane, and contact is performed 5 seconds after the dropping. The angle was measured and used as the contact angle B.

⊚: Contact angle B was 20 ° or less even in 6 cycles 〇: Contact angle B was 20 ° or less in 3 cycles or more and 5 cycles or less Δ: Contact angle B was 20 in 1 cycle or more and 2 cycles or less It was less than ° ×: The contact angle B exceeded 20 ° even in one cycle.

(Measurement of contact angle change width)
The contact angle change width of the contact angle B after the heat cycle treatment with respect to the measured contact angle A immediately after production was obtained from the following formula and ranked according to the following criteria.
Contact angle change rate = contact angle B-contact angle A
⊚: Contact angle change width is less than 5 ° 〇: Contact angle change width is 5 ° or more and less than 10 ° Δ: Contact angle change width is 10 ° or more and less than 20 ° ×: Contact The angle change width is 20 ° or more.

[Evaluation of high temperature and high humidity resistance]
For each superhydrophilic membrane, the water contact angle after storage for 50 to 150 hours in a high temperature and high humidity environment of 85 ° C. and 85% RH was measured by the same method as above, and the contact angle was 20 ° C. The time during which the following can be maintained was determined, and the high temperature and high humidity resistance was evaluated according to the following criteria.
⊚: The contact angle was 20 ° or less even after 150 hours or more. 〇: The contact angle was 20 ° or less after 100 hours or more and less than 150 hours. X: The contact angle exceeded 20 ° in 50 hours.

[Evaluation of wear resistance]
After performing the heat cycle treatment for 3 cycles by the above method, the surface of the superhydrophilic film was rubbed back and forth 1 to 30 times with a Kimwipe moistened with water, and then the contact angle was measured and the contact angle was 20. The number of frictions that can be maintained below ° was determined, and the friction resistance was evaluated according to the following criteria.
⊚: The contact angle was 20 ° or less even when the number of frictions was 30. 〇: The number of frictions was 10 times or more and less than 30 times and the contact angle was 20 ° or less. Less than, the contact angle was 20 ° or less ×: The contact angle exceeded 20 ° even if the number of frictions was 3 times.

[Evaluation of photocatalytic function]
The surface of each superhydrophilic film is marked with magic ink (The Visualiser manufactured by Inkintilegen), stored for 10 hours in an environment of 85 ° C. and 85% RH, and then accumulated ultraviolet rays in an environment of 20 ° C. and 80% RH. As a result, if the magic ink on the surface of the superhydrophilic film disappears after irradiation with ultraviolet rays under the condition of 20J, it is determined that the photocatalytic function is "presence".

The results obtained above are shown in Table II.

As is clear from the results shown in Table II, it is confirmed that the superhydrophilic membrane of the present invention exerts an excellent effect on both heat cycle resistance and high temperature and high humidity resistance with respect to the comparative example. Was made. Further, it can be seen that the superhydrophilic films 11 to 13 having the wear resistance improving layer formed on the outermost surface layer have improved wear resistance, and further formed pores penetrating from the surface portion to the upper surface portion of the photocatalyst layer. It was confirmed that the superhydrophilic membranes 12 and 13 have an excellent photocatalytic function.

1 Super hydrophilic film 2 Substrate 3, 3A, 3B Sodium-containing layer 4 Water contact angle control layer 5 First reflectance adjusting layer unit 6, 6A, 6B Second reflectance adjusting layer unit 7 Low refractive index layer 8, 12 High refraction Rate layer 9 Metal mask 10 Pore 11A 1st low reflectance layer 11B 2nd low reflectance layer 13 Photocatalyst layer 14 Abrasion resistance improving layer E Etching device U Water contact angle control layer unit 101 IAD vapor deposition device 102 Chamber 103 Dome 104 Substrate 105 Evaporative source 106 Evaporative material 107 IAD ion source 108 Ion beam

Claims (24)

A superhydrophilic membrane having at least one sodium-containing layer on the substrate.
A superhydrophilic membrane characterized by having at least one water contact angle control layer on the surface side of the sodium-containing layer. The superhydrophilic membrane according to claim 1, wherein the water contact angle control layer is a sodium-free layer. The superhydrophilic membrane according to claim 1 or 2, wherein the water contact angle control layer contains at least one element selected from magnesium, calcium, cerium and phosphorus. The superhydrophilic film according to any one of claims 1 to 3, wherein the layer thickness of the sodium-containing layer is in the range of 1 to 500 nm. The superhydrophilic film according to any one of claims 1 to 4, wherein the layer thickness of the water contact angle control layer is in the range of 0.1 to 50 nm. The superhydrophilic membrane according to any one of claims 1 to 5, wherein one or more units composed of the sodium-containing layer and the water contact angle control layer are laminated. The superhydrophilic membrane according to any one of claims 1 to 6, wherein the sodium content in the sodium-containing layer is in the range of 1.0 to 20% by mass. According to claim 3, the content of at least one element selected from magnesium, calcium, cerium and phosphorus in at least one layer of the water contact angle control layer is in the range of 0.1 to 20% by mass. The superhydrophilic film according to any one of claims 7. A reflectance adjusting layer unit is provided between the substrate and the sodium-containing layer, and the average light reflectance in the wavelength range of 450 to 780 nm is 3.0% or less. The superhydrophilic film according to any one of claims 1 to 8. The superhydrophilic film according to any one of claims 1 to 9, further comprising a wear resistance improving layer on the water contact angle control layer. On the substrate, as the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer.
A second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer is provided in this order.
The superhydrophilic film according to claim 9 or 10, wherein the layer farthest from the substrate of the first reflectance adjusting layer unit is a photocatalytic layer containing a metal oxide having a photocatalytic function. .. The superhydrophilic film according to claim 11, further comprising pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and expose the surface of the photocatalyst layer. A method for producing a superhydrophilic film, which comprises producing the superhydrophilic film according to any one of claims 1 to 12. A step of forming a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer on the substrate.
At least, a step of forming a second reflectance adjusting layer unit composed of a low refractive index layer, a high refractive index layer and a sodium-containing layer, and
15. The method for producing a superhydrophilic membrane according to the above. The superimposition according to claim 13 or 14, wherein a step of forming a photocatalytic layer containing a metal oxide having a photocatalytic function is provided at a position farthest from the substrate of the first reflectance adjusting layer unit. A method for producing a hydrophilic film. The method for producing a superhydrophilic film according to any one of claims 13 to 15, wherein the water contact angle control layer is formed as a sodium-free layer. The method for producing a superhydrophilic film according to any one of claims 13 to 16, wherein at least one layer of the sodium-containing layer and the water contact angle control layer is formed by a dry film forming method. .. Further, a reflectance adjusting layer unit is formed, and at least one layer of the sodium-containing layer, the water contact angle control layer, and the reflectance adjusting layer unit is formed by a vapor deposition method under a condition where the amount of gas introduced is 5 sccm or more. The method for producing a superhydrophilic film according to any one of claims 13 to 17, wherein the film is formed. As the reflectance adjusting layer unit, a first reflectance adjusting layer unit composed of at least one low refractive index layer and at least one high refractive index layer.
The invention according to any one of claims 13 to 18, wherein the second reflectance adjusting layer unit composed of the low refractive index layer, the high refractive index layer and the sodium-containing layer is formed in this order. A method for producing a superhydrophilic film. Any one of claims 13 to 19, wherein the sodium content in the raw material used for forming the film of at least one layer of the sodium-containing layer is in the range of 1.0 to 20% by mass. The method for producing a superhydrophilic membrane according to. The content of at least one element selected from magnesium, calcium, cerium and phosphorus in the raw material used for forming the film of the water contact angle control layer of at least one layer is in the range of 0.1 to 20% by mass. The method for producing a superhydrophilic membrane according to any one of claims 13 to 20, which is characteristic. Any of claims 13 to 21, which comprises a step of forming a plurality of pores that penetrate from the outermost surface layer to the upper surface of the photocatalyst layer and partially expose the surface of the photocatalyst layer. The method for producing a superhydrophilic membrane according to item 1. An optical member comprising the superhydrophilic film according to any one of claims 1 to 12. The optical member according to claim 23, wherein the optical member is a lens, an antibacterial cover member, an antifungal coating member, or a mirror.

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