JP4014357B2 - Water repellent antifouling film - Google Patents

Description

【００５４】
この結果より明らかなように、実施例１の試験試料は、撥水性、防汚性、密着性の何れにおいても優れていた。しかし、比較例１の試験試料は、撥水性と防汚性に優れるものの密着性に劣り、比較例２の試験試料は、密着性に優れるものの撥水性と防汚性に劣っていた。
【００５５】
【発明の効果】
以上説明したように、本発明の撥水性防汚フィルムによれば、密着シリカ層と表面シリカ層との関係では、両者は何れもシリカで形成されているので、両者は高い密着性を示している。また、密着シリカ層と基材との関係では、炭素含有量が２０原子％未満で形成された密着シリカ層は、表面エネルギーが大きくなっているので、基材との間で高い密着性を示す。本発明の撥水性防汚フィルムは、こうした密着シリカ層を設けたので、撥水性と防汚性がある表面シリカ層の剥離を防ぎ、優れた撥水性と防汚性を発揮し続けるフィルムとすることができる。
【００５６】
また、本発明の撥水性防汚フィルムによれば、炭素含有量が２０〜４０原子％の表面シリカ層は、表面エネルギーが小さく、撥水性と防汚性に優れている。さらに、上記のプラズマＣＶＤ法で成膜すれば、炭素含有量を制御して表面エネルギーを調整し易く、撥水性と防汚性を安定して発揮できる表面シリカ層を容易に形成することができる。
【図面の簡単な説明】
【図１】本発明の撥水性防汚フィルムの層構成の一例を示す断面図である。
【図２】プラズマＣＶＤ装置の一例を示す構成図である。
【符号の説明】
１ 撥水性防汚フィルム
２ 基材
３ 密着シリカ層
４ 表面シリカ層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-repellent antifouling film having a water-repellent and antifouling silica layer on the outermost surface, and more specifically, a water-repellent antifouling film in which the adhesion of the silica layer is improved and peeling does not occur About.
[0002]
[Prior art]
Conventionally, as the water-repellent antifouling film, a film having water repellency and antifouling property by wet coating (wet film formation) with a fluorine compound layer on the outermost surface thereof has been used. However, the fluorine compound-containing solution used for coating has a problem that it is expensive and may adversely affect the environment.
[0003]
In order to solve these problems, it has been studied that a silica layer having a small surface energy has excellent water repellency and antifouling properties, and such a silica layer is regarded as a promising alternative to the above-mentioned fluorine compound layer. .
[0004]
[Problems to be solved by the invention]
However, the above-described silica layer having water repellency and antifouling property has a problem that the adhesive force between the silica layer and the base material becomes small due to the small surface energy.
[0005]
The present invention has been made to solve the above problems, and provides a water-repellent antifouling film that does not cause peeling by improving the adhesion of a silica layer having water repellency and antifouling properties.
[0006]
[Means for solving the problems]
The water-repellent antifouling film of the present invention has a surface silica layer having water repellency and antifouling properties on the outermost surface, and an adhesive silica having a carbon content of less than 20 atomic% between the surface silica layer and the substrate. It is characterized by having a layer.
[0007]
According to this invention, it has the contact | adherence silica layer whose carbon content is less than 20 atomic% between the surface silica layer and the base material. At this time, in the relationship between the close-contact silica layer and the surface silica layer, since both are formed of silica, both show high adhesiveness. On the other hand, in the relationship between the adhesion silica layer and the substrate, the adhesion silica layer formed with a carbon content of less than 20 atomic% has high surface energy, and thus exhibits high adhesion with the substrate. . Accordingly, since the water-repellent antifouling film of the present invention is provided with such a close-contact silica layer, the surface silica layer having water repellency and antifouling property is prevented from being peeled off and continues to exhibit excellent water repellency and antifouling properties. It can be.
[0008]
The water-repellent antifouling film is characterized in that the surface silica layer and the adhesion silica layer are formed by a plasma CVD method.
[0009]
According to the present invention, the film formation by the plasma CVD method can chemically bond both at the interface between the adhesion silica layer and the substrate and at the interface between the surface silica layer and the adhesion silica layer. Therefore, the adhesion of each layer at each interface can be made sufficiently high. Furthermore, since the plasma CVD method can form a film with a gas containing carbon and easily control the film forming conditions, the carbon content and surface energy of each layer can be adjusted to a desired range. In addition, since a close-contact silica layer can be formed on a substrate at a low temperature that does not cause thermal damage to the polymer resin, and further a surface silica layer can be formed thereon, it is preferable when a polymer film is used as the substrate. Applicable.
[0010]
In the water-repellent antifouling film, the surface silica layer preferably has a carbon content of 20 to 40 atomic%.
[0011]
According to this invention, the surface silica layer having a carbon content of 20 to 40 atomic% has a small surface energy and is excellent in water repellency and antifouling properties. Furthermore, if the film is formed by the above plasma CVD method, it is easy to adjust the surface energy by controlling the carbon content, and a surface silica layer that can stably exhibit water repellency and antifouling property can be easily formed. .
[0012]
In the water-repellent antifouling film, the surface silica layer preferably has a refractive index of 1.40 to 1.70 (wavelength λ: 633 nm).
[0013]
According to the present invention, in addition to the above water repellency and antifouling property, the surface silica layer has a refractive index of 1.40 to 1.70, more preferably 1.40 to 1.50, thereby providing water repellency. It can also be used as an antireflection film with antifouling properties.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view showing an example of the layer structure of the water-repellent antifouling film of the present invention. The water-repellent antifouling film 1 of the present invention has a surface silica layer 4 having water repellency and antifouling properties on the outermost surface, and an adhesive silica layer 4 between the surface silica layer 4 and the substrate 2. It is. Hereinafter, each layer constituting the present invention will be described.
[0015]
(1) Base material
The base material 2 is a target to impart water repellency and antifouling properties by the surface silica layer 4, and the material is selected according to the use of the base material that requires water repellency and antifouling properties. The material of the substrate is not particularly limited, such as a polymer film, a metal film, an inorganic material film, and the like.
[0016]
Polymer films include triacetyl cellulose film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic film, polyurethane film, polyester film, polycarbonate film, polysulfone film, polyether film, trimethyl Examples include pentene film, polyether ketone film, acrylonitrile film, methacrylonitrile film, polypropylene film, polyamide film, polyimide film, polyethylene film, polyethylene naphthalate film, cyclic polyolefin film, and ethylene-tetrafluoroethylene copolymer film. be able to. The color or the like can be selected according to the application, and a transparent film or a colorless film in the visible light range can be arbitrarily selected. Among these, the uniaxial or biaxially stretched polyester film is excellent in transparency and heat resistance, and thus is suitably used as a water-repellent antifouling film having an antireflection function, and a polyethylene terephthalate (PET) film is particularly preferable. Triacetylcellulose is also preferably used in that it has no optical anisotropy.
[0017]
Examples of the metal film and the inorganic material film include an aluminum film, a copper film, and a stainless steel film.
[0018]
The base material 2 is conveniently a long product wound up in a roll shape. The thickness of the base material 2 varies depending on the use of the resulting water-repellent antifouling film 1 and therefore cannot be defined unconditionally, but is usually preferably about 6 μm to 188 μm.
[0019]
In addition, the base material 2 includes those obtained by laminating other layers on the above-described film. For example, even in the case of a laminate in which an anchor coat layer, a hard coat layer, various refractive index layers, a titanium oxide layer and the like are provided on one side or both sides of a polymer film as necessary, the substrate 2 is used in the present invention. . Since these various layers are arbitrarily selected and laminated according to the use of the water-repellent antifouling film, they will be described in detail in the explanation of other laminated materials described later.
[0020]
(2) Adhering silica layer
The close-contact silica layer 3 is provided so as to be in contact with each layer between the base material 2 and the surface silica layer 4 and acts to prevent the surface silica layer 4 having water repellency and antifouling properties from being peeled off.
[0021]
This adhesion silica layer 3 is a silicon oxide film having a carbon content of less than 20 atomic%. Since the adhesion silica layer 3 having such a carbon content has a large surface energy of 50 mN / m to 70 mN / m, the adhesion with the substrate 2 is improved. Furthermore, since the contact silica layer 3 is formed of the same silica (silicon oxide) as the surface silica layer 4 provided in contact therewith, it exhibits high adhesion with the surface silica layer 4. When the carbon content is 20 atomic% or more, the surface energy of the adhesion silica layer 3 may be less than 40 mN / m, and the adhesion with the substrate 2 may be reduced. The lower limit of the carbon content of the adhesion silica layer 3 is not particularly limited, but is slightly different depending on the film forming method described later. For example, when a compound containing carbon is used as a film forming raw material, carbon is inevitably contained. However, when a compound containing carbon is not used as a film forming raw material, carbon is not contained.
[0022]
The thickness of the adhesion silica layer 3 should just be sufficient to exhibit the effect | action, and is 1-100 nm normally, Preferably it is 5-30 nm.
[0023]
The formation method of the contact | adherence silica layer 3 is not specifically limited. For example, a vacuum deposition method, a sputtering method, an ion plating method, a plasma CVD method, a thermal CVD method, a sol-gel method, or the like can be used. These methods are selected in consideration of the type of base material, the type of film forming raw material, the ease of film forming, the process efficiency, etc., and any method is based on the film forming principle. Since both can be chemically bonded at the interface between the layer 3 and the substrate 2, the adhesion between them can be made sufficiently high.
[0024]
Among these, the plasma CVD method can form a silica film at a low temperature (a range of about −10 to 150 ° C.) that does not cause thermal damage to the polymer resin. It is preferably applied to the formation of the adhesion silica layer 3 of the water repellent antifouling film 1. The plasma CVD method is a method in which a raw material gas at a constant pressure is discharged into a plasma state, and a chemical reaction on the surface of the substrate is promoted by active particles generated in the plasma. There is an advantage that the composition of the film obtained can be controlled by the type / flow rate, film forming pressure, input power, and the like.
[0025]
Specifically, plasma is supplied by supplying a predetermined mixed gas at a predetermined flow rate into a reaction chamber of a plasma CVD apparatus, and applying DC power or power having a constant frequency within a range from low frequency to high frequency to an electrode. Is generated, and the gas component in the mixed gas reacts in the plasma, whereby the adhesion silica layer 3 is formed on the substrate 2. The type of the plasma CVD apparatus used is not particularly limited, and various types of plasma CVD apparatuses can be used. Usually, an apparatus capable of continuous film formation is preferably used, which can use a long polymer resin film as the base material 2 and can continuously form the adhesion silica layer 3 while transporting it.
[0026]
Examples of the mixed gas include (a) hexamethyldisiloxane (HMDSO), 1,1,3,3-tetramethyldisiloxane (TMDSO), vinyltrimethoxysilane, vinyltrimethylsilane, tetramethoxysilane (TMOS), methyltrimethyl. A mixture of an organic silicon compound gas such as methoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, or hexamethyldisilazane and oxygen gas, or (b) a silane-based gas and oxygen gas or oxide gas Such as SiH _Four N for gas ₂ O gas, NO gas, CO gas, CO ₂ Gas, O ₂ A gas mixed with gas, Ar gas or the like can be preferably used.
[0027]
In addition, the adhesion silica layer 3 formed as described above may contain carbon atoms derived from gas components depending on the type of mixed gas used as a raw material. It is necessary to adjust the carbon content within the above range. For example, when an organosilicon compound gas and an oxygen gas are used as a mixed gas, the flow rate ratio between the organosilicon compound gas and the oxygen gas, the magnitude of the input power per unit flow rate of the organosilicon compound gas, etc. are adjusted to Can be controlled within the range. Specifically, by adjusting the flow rate ratio of [oxygen gas / organosilicon compound gas] in the range of about 3 to 50, SiO 2 ₂ By making a like film to suppress the mixing of carbon, or increasing the input power per unit flow rate of the organosilicon compound gas, the Si-C bond can be easily broken to suppress the mixing of carbon into the layer. be able to. The upper limit of the flow rate ratio is defined for convenience, and there is no particular problem even if it exceeds 50. In addition, when a silane-based gas and an oxygen gas or an oxide gas are used as a mixed gas, carbon is less mixed than when a mixed gas composed of the above-described organosilicon compound gas and oxygen gas is used. Therefore, it is easy to control the carbon content within the above range.
[0028]
The adhesive silica layer 3 thus formed has few Si—C bonds, so that SiO 2 ₂ Like a homogeneous membrane. The carbon content can be measured by an apparatus capable of quantitatively measuring each component of Si, O, and C constituting the adhesion silica layer. As a typical measuring apparatus, evaluation is performed based on results measured by ESCA (Electron spectroscopy for chemical analysis), RBS (Rutherford back scattering), and Auger electron spectroscopy.
[0029]
(3) Surface silica layer
The surface silica layer 4 is a layer that is provided on the adhesion silica layer 3 and constitutes the outermost surface of the water-repellent antifouling film of the present invention, and exhibits water repellency and antifouling properties.
[0030]
The surface silica layer 4 is a silicon oxide film having a carbon content of 20 to 40 atomic%. Since the surface silica layer 4 having such a carbon content has a small surface energy of 20 mN / m to 40 mN / m and a large contact angle with water of 70 ° to 110 °, it has excellent water repellency and antifouling properties. It can be demonstrated. When the carbon content is less than 20 atomic%, the surface energy of the surface silica layer 4 may exceed 50 mN / m, or the contact angle with water may be less than 60 °, so that sufficient water repellency and antifouling properties are obtained. May not be indicated. If the carbon content exceeds 40 atomic%, the density may become small and sparse, and sufficient water repellency and antifouling properties may not be exhibited.
[0031]
On the other hand, since both of them are formed of silica in relation to the close-contact silica layer 3, the surface silica layer 4 exhibits high adhesiveness with the close-contact silica layer 3 and is not easily peeled off.
[0032]
The thickness of the surface silica layer 4 may be a thickness sufficient to exhibit the action of water repellency and antifouling properties, and is usually 1 to 1000 nm, preferably 2 to 200 nm.
[0033]
About the formation method of the surface silica layer 4, similarly to the case of the above-mentioned adhesion silica layer 3, it is not specifically limited, The various methods mentioned above can be used. These methods are selected in consideration of the type of film forming raw material, easiness of film forming, process efficiency, etc., and any method is based on the surface forming principle and the surface silica layer 4 and the contact silica. Both can be chemically bonded at the interface of the layer 3, and both are formed of the same silica as described above, so that the adhesion between them can be made sufficiently high. In the present invention, it is convenient to form the surface silica layer 4 by the same method as the adhesion silica layer 3. For example, when the contact silica layer 3 is formed by the plasma CVD method, the surface silica is used for the same reason as the case of the contact silica layer 3 (low temperature film formation is possible and carbon content and surface energy can be easily adjusted). The layer 4 is also preferably formed by a plasma CVD method, but can also be formed by a different method.
[0034]
Since the surface silica layer 4 to be formed needs to contain 20 to 40 atomic% of carbon, the film forming method and the type of source gas are selected, and the film forming conditions are controlled to control the carbon within the above range. It is necessary to adjust the content.
[0035]
For example, it is preferable to form a film by a plasma CVD method using a mixed gas composed of an organic silicon compound gas having carbon and oxygen gas, and particularly, the organic silicon compound gas to be used contains a lot of methyl groups. Specifically, hexamethyldisiloxane (HMDSO) or 1,1,3,3-tetramethyldisiloxane (TMDSO) is preferable. At this time, the flow rate ratio between the organosilicon compound gas and the oxygen gas, the magnitude of the input power per unit flow rate of the organosilicon compound gas, and the like can be adjusted and controlled within the above range. For example, when the flow rate ratio of [oxygen gas / organosilicon compound gas] is adjusted to be small within the range of 0 to 1 (when the organosilicon compound gas flow rate is relatively large), or when the organosilicon compound gas is charged per unit flow rate When the power is reduced, Si—C bonds remain in the film as they are, so that the carbon content can be increased as in the above range. The measurement of the carbon content is as described above.
[0036]
The surface silica layer 4 preferably has a refractive index of 1.40 to 1.70, more preferably 1.40 to 1.50 (wavelength λ: 633 nm). Since the surface silica layer 4 having such a refractive index also has an antireflection effect, the antireflection function can be imparted to the obtained water-repellent antifouling film. In order to set the refractive index to 1.40 to 1.70, more preferably 1.40 to 1.50, for example, when an organic silicon compound gas and an oxygen gas are used as a mixed gas by a plasma CVD method, those gases are used. The refractive index in the above range can be controlled by adjusting the flow rate ratio, the magnitude of the input power per unit flow rate of the organosilicon compound gas, and the like. Specifically, the flow rate ratio of [oxygen gas / organosilicon compound gas] is further limited to a range of about 0.2 to 0.5, or the input power per unit flow rate of the organosilicon compound gas is reduced. Can be controlled. Such a refractive index is obtained by measuring the transmittance and reflectance measured by an optical spectrometer and evaluating the refractive index at 633 nm using an optical interferometry.
[0037]
(4) Water-repellent antifouling film
The water-repellent antifouling film of the present invention constituted as described above has a surface silica layer 4 excellent in water repellency and antifouling property on the outermost surface, and the surface silica layer 4 has an adhesion silica layer 3. And firmly adhered to the base material 2. Therefore, the surface silica layer 4 does not easily peel off, and a film that continues to exhibit excellent water repellency and antifouling properties can be obtained.
[0038]
Further, as described above, by further adjusting the refractive index of the surface silica layer 4 and forming it so as to have an antireflection effect, a water-repellent antifouling film having an antireflection function can be obtained. The water-repellent antifouling film thus produced can be used for various displays such as liquid crystal displays, plasma displays, CRT displays, word processor display screens, TV brown cans, display bodies such as measuring instruments, rearview mirrors, goggles, window glass, etc. It can be preferably used. In particular, when used under harsh conditions such as a touch panel and a display having a pen input function, it is possible to continue to exhibit excellent water repellency and antifouling properties and further antireflection functions.
[0039]
(5) Other laminated materials
In the water-repellent antifouling film of the present invention, other laminated materials according to its use, for example, an anchor coat layer and a back coat layer, and a high refractive index layer, a medium refractive index layer when providing an antireflection function, A titanium oxide layer can be further provided. In such a case, the “substrate” in the present invention is defined as including the substrate film and each of the above layers.
[0040]
The anchor coat layer can be provided for the purpose of assisting the close contact with the close contact silica layer 3 according to the nature of the material itself of the base material 2 to be used and the surface form (for example, the surface roughness) derived from the processing history. . The anchor coat layer is formed during or after the production of the base film. As an anchor coating agent for providing an anchor coat layer, polyester resin, isocyanate resin, urethane resin, acrylic resin, ethylene vinyl alcohol resin, vinyl modified resin, epoxy resin, modified styrene resin, modified silicon resin, alkyl titanate, etc. These can be used alone or in combination of two or more. A conventionally well-known additive can also be added to an anchor coating agent.
[0041]
Further, in the present invention, the surface of the substrate 2 is subjected to treatment such as corona discharge treatment, plasma treatment in vacuum or air, flame treatment, glow discharge treatment, roughening treatment, chemical treatment, etc. Adhesion with the silica layer 3 can be assisted and its adhesion can be improved.
[0042]
The hard coat layer is a layer formed to give strength to the water-repellent antifouling film of the present invention, and can be provided as necessary. For example, a UV curable acrylic hard coat layer or a thermosetting silicone hard coat layer can be formed by a normal coating method.
[0043]
The high refractive index layer, medium refractive index layer, and titanium oxide layer are preferably provided in an arbitrary laminated configuration as a part of the substrate 2 when providing an antireflection function. For example, a base material 2 is prepared by sequentially laminating a transparent polymer film / medium refractive index layer / high refractive index layer or titanium oxide layer, and an adhesive silica layer 3 is formed on the high refractive index layer or titanium oxide layer. It is also possible to provide a water-repellent antifouling film having an antireflection function by providing a surface silica layer 4 adjusted to a predetermined refractive index. Here, a titanium oxide layer can be suitably used as the high refractive index layer, and the refractive index is preferably 2.0 or more and 2.9 or less (wavelength λ = 550 nm). Moreover, the refractive index of the medium refractive index layer is a substance that falls within the range of 1.5 to 2.0, for example, Al. ₂ O _Three , SiN, SiON, ZrO ₂ , SiO ₂ ZnO ₂ There is no particular limitation as long as it is a layer formed by dispersing the fine particles in an organic silicon compound or the like.
[0044]
【Example】
The present invention will be described more specifically with reference to the following examples and comparative examples.
[0045]
Example 1
As the substrate 2, a polyethylene terephthalate (PET) film (manufactured by Unitika) having a thickness of 100 μm was used. An adhesive silica layer 3 and a surface silica layer 4 made of silicon oxide were formed on one surface of the substrate 2 by a plasma CVD method.
[0046]
A plasma CVD apparatus is shown in FIG. The plasma CVD apparatus 50 is a capacitively coupled plasma CVD continuous film forming apparatus. First, a web-like PET film 51 is unwound from an unwinding section 52 and introduced into a reaction chamber (a, b, c) in a vacuum vessel 53, and a predetermined drum is formed on a stratification drum 54 in the reaction chamber. A layer is formed and wound up by the substrate winding unit 56. This plasma CVD apparatus 50 has a plurality of (three) reaction chambers, and each reaction chamber (a, b, c) is isolated by an isolation wall 55. In each reaction chamber, electrode plates a1, b1, and c1 and source gas inlets a2, b2, and c2 are installed, respectively. Each reaction chamber (a, b, c) is installed along the outer periphery of the stratification drum 54, and the base film is introduced into the reaction chamber in synchronization with the stratification drum 54. A surface silica layer 4 is formed. At this time, since the source gas introduced into each reaction chamber can be arbitrarily changed, each layer can be formed in each reaction chamber. In this example, the contact silica layer 3 was formed in the reaction chamber a, the surface silica layer 4 was formed in the reaction chamber b, and the reaction chamber c was not used.
[0047]
The film formation conditions for the adhesion silica layer 3 include hexamethyldisiloxane (HMDSO) gas (Toray Dow Corning Silicone Co., SH200, 0.65 CSt) 150 sccm and oxygen gas (Taiyo Toyo Oxygen Co., Ltd.). The film was formed until the film thickness reached 50 nm by adjusting the film formation time with an input power of 2 kW and a film formation pressure of 66.65 Pa (0.5 Torr). Note that sccm is an abbreviation for standard cubic cm per minute, and slm is an abbreviation for standard litter per minute. The film formation conditions for the surface silica layer 4 are the same HMDSO gas 150 sccm and oxygen gas 150 sccm as described above as the source gas, an input power of 0.5 kW, a film formation pressure of 66.65 Pa (0.5 Torr), and a film formation time. Were adjusted until the film thickness reached 50 nm. Thus, a test sample of Example 1 was obtained in which the total thickness of the adhesion silica layer 3 and the surface silica layer 4 was 100 μm.
[0048]
(Comparative Example 1)
Using only the reaction chamber b under the same apparatus and conditions as in Example 1, only the surface silica layer 4 having a thickness of 100 nm was formed and used as a test sample of Comparative Example 1.
[0049]
(Comparative Example 2)
Using the same apparatus and conditions as in Example 1, only the reaction chamber a was used, and only the adhesion silica layer 3 having a thickness of 100 nm was formed, and used as a test sample of Comparative Example 2.
[0050]
(Characteristic evaluation)
The film thickness of each silica layer was measured using an ellipsometer (model number: UVISELTM, manufacturer: JOBIN YVON). The composition analysis of each silica layer was measured by XPS (photoelectron spectrometer, model number: ESCALAB, manufacturer: VG Scientific), and each content of silicon, oxygen, and carbon was measured. Prior to XPS measurement, about 1 nm was etched with argon ions to remove the surface contamination layer.
[0051]
Adhesion was evaluated by measuring laminate strength. In the measurement of the laminate strength, first, about 1 μm of an adhesive made of a 7% solution of a two-component curable polyurethane resin was applied on the outermost surface of each test sample of Example 1 and Comparative Examples 1 and 2, and then on that. After a part of a 25 μm thick PET laminate film was attached, the adhesive was cured. Thereafter, each test sample was cut to a size of 100 mm × 15 mm, and the cut test sample was firmly attached on a horizontal fixing base so that the above-mentioned laminate film side was on the top. Next, the end on the side where the laminate film was not attached was peeled off at a speed of 50 mm / min in the vertical direction and in the longitudinal direction (100 mm direction) of the test sample. Adhesiveness was evaluated using the measured strength as the laminate strength at the torn interface.
[0052]
The water repellency and antifouling properties were evaluated by measuring the contact angle of water and measuring the surface energy. The contact angle of water was measured with a FACE contact angle meter CA-D type (manufactured by Kyowa Interface Science). For the surface energy, the contact angle of ethylene glycol, n-hexadecane and methylene iodide was measured with the above contact angle meter, and the surface energy was calculated from the value and the extended Fowkes theory. The obtained results are shown in Table 1.
[0053]
[Table 1]

[0054]
As is clear from this result, the test sample of Example 1 was excellent in any of water repellency, antifouling property, and adhesion. However, although the test sample of Comparative Example 1 was excellent in water repellency and antifouling property, it was inferior in adhesion, while the test sample in Comparative Example 2 was excellent in adhesion but poor in water repellency and antifouling property.
[0055]
【The invention's effect】
As described above, according to the water-repellent antifouling film of the present invention, since both are formed of silica in the relationship between the contact silica layer and the surface silica layer, both exhibit high adhesion. Yes. In addition, in the relationship between the adhesion silica layer and the substrate, the adhesion silica layer formed with a carbon content of less than 20 atomic% has high surface energy, and thus exhibits high adhesion with the substrate. . Since the water-repellent antifouling film of the present invention is provided with such a close-contact silica layer, the surface silica layer having water repellency and antifouling properties is prevented from peeling off, and the film continues to exhibit excellent water repellency and antifouling properties. be able to.
[0056]
Moreover, according to the water-repellent antifouling film of the present invention, the surface silica layer having a carbon content of 20 to 40 atomic% has a small surface energy and is excellent in water repellency and antifouling properties. Furthermore, if the film is formed by the above plasma CVD method, it is easy to adjust the surface energy by controlling the carbon content, and a surface silica layer that can stably exhibit water repellency and antifouling property can be easily formed. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a layer structure of a water-repellent antifouling film of the present invention.
FIG. 2 is a configuration diagram showing an example of a plasma CVD apparatus.
[Explanation of symbols]
1 Water repellent antifouling film
2 Base material
3 Adhering silica layer
4 Surface silica layer

Claims (2)

It has a surface silica layer with water repellency and antifouling properties on the outermost surface, and has an adhesion silica layer between the surface silica layer and the substrate,
The surface silica layer is composed of silicon, oxygen, and carbon elements, has a carbon content of 20 to 40 atomic%, a surface energy of 20 to 40 mN / m, and a contact angle with water. 70-110 °,
On the other hand, the said adhesion silica layer is comprised from each element of silicon, oxygen, and carbon, carbon content is less than 20 atomic%, surface energy is 50-70 mN / m,
The water-repellent antifouling film is characterized in that the surface silica layer and the adhesion silica layer are formed by a plasma CVD method with a film forming pressure of 0.5 Torr.   2. The water-repellent antifouling film according to claim 1, wherein the surface silica layer has a refractive index of 1.40 to 1.70 (wavelength λ: 633 nm).

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