JP6503743B2 - Member, a touch panel including the member, and an image display device including the touch panel - Google Patents

Description

  The present invention relates to a member in which an antifouling layer is formed on a substrate, a touch panel including the member, and an image display apparatus including the touch panel.

Image display devices such as liquid crystal displays, plasma displays, organic and inorganic EL displays, electronic paper, VFDs (Vacuum Fluorescent Displays), EPDs (Electrophoretic Displays), etc., touch panels, portable electronic devices such as mobile phones and music players, CDs (Compact) In the case of optical recording media such as Disk), DVD (Digital Versatile Disk), Blu-ray Disc, etc., dirt such as fingerprints, sebum, sweat, etc. may adhere to the surface during handling. Such dirt may reduce the visibility in the case of an image display device, a touch panel, or a display of various electronic devices, and may adversely affect operability when operating on the display. Also, in the above optical recording medium, failures may occur in signal recording and reproduction.
Therefore, it is necessary to impart on the surface of the article the characteristics (antifouling property) such as the adhesion preventing property of the contamination and the easiness of wiping off the contamination.
Therefore, various studies have been made to form a thin film having antifouling property or water repellency on the surface of an article.

For example, Patent Document 1 discloses an antifouling thin film formed on a substrate surface using a fluoroalkylsilane having antifouling property or water repellency by vacuum evaporation.
Further, Patent Document 2 discloses an organic-inorganic hybrid film formed by hydrolyzing and condensation-polymerizing an organic silane and a metal alkoxide on a solid surface.

JP, 2006-336109, A JP, 2013-213181, A

However, the thin film described in Patent Document 1 can reduce surface free energy, but there is no mention of slipperiness. Here, in the present invention, the term "slip down" is an index that represents the difficulty of attaching a stain and the ease of removing a stain. In general, the surface modified with a perfluoroalkyl group does not have slipperiness due to the rigidity of the perfluoroalkyl group, and the antifouling properties such as fingerprint adhesion and wiping are not sufficient. Therefore, patent document 1 is considered to be the same.
In addition, the film described in Patent Document 2 improves the slipperiness of the droplets on the surface of the film by using a metal alkoxide together with the organosilane, as compared with a thin film formed of a conventional organic silane alone. In the case of using alkylsilane, the surface free energy is not sufficiently lowered, and in the case of using perfluoroalkylsilane, the perfluoroalkyl group is rigid. It was not enough.

In addition, operations such as touching (tap) the screen with a finger and moving the finger while touching (slide, pinch) are essential for the operation of a terminal having a touch panel display such as a smartphone or a tablet terminal. Therefore, the frequency of stain due to fingerprint adhesion is higher than that of conventional antifouling members used in displays such as televisions, and the demand for prevention of stain due to fingerprint adhesion is increasing, and is higher than the conventionally required antifouling property. Performance is required.
However, the conventional antifouling member as described above is insufficient for solving the fingerprint adhesion problem unique to touch panels, in which a fingerprint is adhered while touching while actually applying pressure with a finger.

  The present invention has been made in view of such circumstances, and is provided with a member excellent in antifouling properties such as adhesion prevention property of dirt and easiness of wiping dirt, a touch panel provided with the member, and the touch panel An object of the present invention is to provide an image display apparatus.

As a result of intensive studies to solve the above problems, the present inventors found that the antifouling layer contains a perfluoropolyether structure and a siloxane structure, and the three-dimensional skewness SRsk of the surface of the antifouling layer satisfies a specific condition. It has been found that the antifouling property of the member surface can be improved by this.
The present invention has been completed based on such findings.

That is, the present invention provides the following [1] to [10].
[1] A member having an antifouling layer formed on a substrate, wherein the antifouling layer comprises a perfluoropolyether structure and a siloxane structure, and the three-dimensional skewness SRsk of the surface of the antifouling layer A member satisfying the following condition (1):
0 <SRsk (1)
[2] The member according to claim 1, wherein the three-dimensional arithmetic mean roughness SRa of the surface of the antifouling layer satisfies the following condition (2).
0.3 nm ≦ SRa ≦ 3.0 nm (2)
[3] The member according to claim 1 or 2, wherein the three-dimensional ten-point average roughness SRz of the surface of the antifouling layer satisfies the following condition (3).
SRz ≦ 20.0 nm (3)
[4] The member according to any one of the above [1] to [3], wherein the antifouling layer is formed by a sea-island structure.
[5] The member according to the above [4], wherein the ratio of island portions in the sea-island structure is 25 to 90%.
[6] The member according to any one of the above [1] to [5], wherein the perfluoropolyether structure and the siloxane structure are condensation polymers of alkoxysilanes having a perfluoropolyether structure.
[7] The member according to the above [6], wherein the condensation polymer of the alkoxysilane having a perfluoropolyether structure is a condensation polymer of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane.
[8] The member according to any one of the above [4] to [7], wherein the main component of the island portion of the sea-island structure is a perfluoropolyether structural site.
[9] A touch panel comprising the member according to any one of the above [1] to [8].
[10] An image display device comprising the touch panel according to the above [9].

  ADVANTAGE OF THE INVENTION According to this invention, the member excellent in antifouling property, the touch panel provided with this member, and the image display apparatus provided with this touch panel can be provided, maintaining the optical physical property and physical property which it has originally.

It is an AFM observation image of the antifouling layer surface of a member obtained in Example 3. It is a height distribution curve of the antifouling layer surface of Example 3.

First, the members of the present invention will be described.
<Members>
The member of the present invention is obtained by forming an antifouling layer comprising a perfluoropolyether structure and a siloxane structure on a substrate, and the three-dimensional skewness SRsk of the surface of the antifouling layer satisfies a specific condition.

[Antifouling layer]
The antifouling layer used in the member of the present invention is an antifouling layer, and the three-dimensional skewness SRsk of the surface of the antifouling layer satisfies the following condition (1).
0 <SRsk (1)

The three-dimensional skewness SRsk of the antifouling layer surface is an index that represents the symmetry of the surface shape curved surface with the average surface as the center, and indicates the deviation of the surface height distribution. When SRsk = 0, it indicates that the height distribution of the surface asperities is symmetrical with respect to the mean line. Further, when SRsk <0, it indicates that the height distribution is biased to the upper side with respect to the average surface, and when SRsk> 0, it indicates that the height distribution is biased to the lower side with respect to the average surface.
Since the surface of the antifouling layer has SRsk> 0, it indicates that a thin-shaped protrusion is appropriately present on the surface of the antifouling layer. The protrusions are considered to be those in which the perfluoropolyether structural site rises in the vicinity of the surface of the antifouling layer.
Further, the upper limit value of the three-dimensional skewness SRsk of the surface of the antifouling layer is not particularly limited, but from the viewpoint of the presence of a protrusion having a suitable height, it is preferably 3 or less, more preferably 2.6 or less, still more preferably It is less than 2.0.

In the present invention, SRsk is a three-dimensional extension of the skewness Rsk of the roughness curve of the two-dimensional roughness parameter described in JIS B0601: 1994, and orthogonal coordinate axes X and Y are placed on the reference surface, Assuming that the measured surface shape curve is z = f (x, y) and the size of the reference surface is Lx and Ly, the following equation (a) is calculated.

Here, Sq is the root mean square deviation of the surface height distribution defined by the following equation (b).

In the present invention, the value of SRsk is measured at an area of Lx = 10 μm and Ly = 10 μm at 20 points in the above measurement area, and is calculated by averaging the measured 20 points.
Similarly, regarding the values of SRa and SRz described later, 20 points are measured in the measurement area, and the average is used to calculate.

It is preferable from the viewpoint of further exhibiting the effect of the present invention that the three-dimensional arithmetic average roughness SRa of the surface of the antifouling layer satisfies the following condition (2).
0.3 nm ≦ SRa ≦ 3.0 nm (2)
The above-mentioned SRa can be used as an index of flatness, and indicates that the smaller the SRa on the surface of the antifouling layer, the higher the flatness.
The three-dimensional arithmetic mean roughness SRa of the antifouling layer surface is preferably 0.3 nm or more and 3.0 nm or less, more preferably 0.5 nm or more and 2.5 nm or less, more preferably 0.6 nm or more and 2.0 nm The thickness is more preferably 0.6 nm or more and 1.5 nm or less. The condition that SRa satisfies the condition (2) indicates that the protrusion is present in an appropriate amount in the vicinity of the surface of the antifouling layer, and that the non-projecting portion has a gentle wave shape. For this reason, when SRa satisfies condition (2), the effect of the present invention can be more easily exhibited.

In the present invention, SRa is a three-dimensional extension of the arithmetic mean roughness Ra of the two-dimensional roughness parameter described in JIS B0601: 1994. Assuming that a curved surface is Z (x, y), the following equation (c) is calculated.

(Wherein, A = Lx × Ly)

It is preferable from the viewpoint of further exhibiting the effect of the present invention that the three-dimensional ten-point average roughness SRz of the surface of the antifouling layer satisfies the following condition (3).
SRz ≦ 20.0 nm (3)
Here, in the present invention, SRz is a three-dimensional extension of the ten-point average roughness Rz of the two-dimensional roughness parameter described in JIS B0601: 1994.
The three-dimensional ten-point average roughness SRz of the antifouling layer surface is preferably 20.0 nm or less, more preferably 5.0 nm or more and 16.0 nm or less, and still more preferably 6.0 nm or more and 13.0 nm or less.

  In addition, it is preferable to measure a three-dimensional roughness curved surface using an interference microscope from simplicity. Examples of such an interference microscope include “New View” series manufactured by Zygo.

The antifouling layer is preferably formed of a sea-island structure from the viewpoint of exhibiting the effects of the present invention. By forming the antifouling layer into a sea-island structure, it is possible to ensure the wiping aptitude for dirt while securing free energy.
Actually, when an AFM observation image was analyzed on the antifouling layer surface of the member of the present invention, as shown in FIG. 1, the antifouling layer surface has a gentle wave shape (sea portion), and the wave shape (sea portion) ) Has a sea-island structure in which discontinuous protrusions (islands) having a diameter of about 200 to 1000 nm and a height of about 10 to 30 nm are present.

It is preferable from the viewpoint of exhibiting the effect of the present invention that the ratio of the island portion of the sea-island structure is 25 to 90%, more preferably 30 to 85%, and still more preferably 40 to 80%. .
The proportion of islands in the sea-island structure is determined by measuring the shape of the surface of the antifouling layer with an atomic force microscope (AFM) and calculating the average value of the height data of the surface of the antifouling layer [average value or more The number of measurement points having a height of 100 × 100 / the number of all measurements] can be calculated by measuring 20 points and calculating the average of the measured 20 points.

FIG. 2 is a height distribution curve of the surface of the antifouling layer of Example 3. In FIG. 2, “w” represents the height indicating the peak value (frequency 100) of the height distribution curve and the height on the lower side of the height indicating the half (frequency 50) of the peak value. The difference (hereinafter, the difference is referred to as “half-width on the sea side”) is expressed. The half width at half maximum (w) on the sea side is preferably 0.5 to 3.0 nm, more preferably 0.7 to 2.8 nm, still more preferably 0.8 to 0.5, from the viewpoint of facilitating the effects of the present invention. It is 2.5 nm.
While satisfying the above three-dimensional skewness range, the half width at half maximum (w) on the sea side being the above range means that the sea part in the sea-island structure on the surface of the antifouling layer is uniform and shallow It indicates that there are many islands with constant elevation. Therefore, when the three-dimensional skewness and the half width at the sea side satisfy the above ranges, the effects of the present invention can be easily exhibited.

  The height distribution curve is an approximate curve obtained by linear interpolation of the values of each section of the height distribution histogram. Further, the value (frequency) of each section is assigned to the peak center of each section of the histogram. For example, when a certain section of the histogram is X nm to Y nm, the value (frequency) of the section is assigned to the position of (X + Y) / 2 nm. Further, in order to accurately reflect the height distribution of the sea-island structure on the surface of the antifouling layer, it is preferable that the histogram which is the basis of the height distribution curve be sufficiently narrow in width. If the width of the section is 0.2 nm or less, the height distribution can be accurately reflected. On the other hand, if the width of the section is too narrow, the influence of noise will increase. Therefore, the width of the section is preferably 0.05 to 0.2 nm. For example, the width of the section is 0.098 nm in Examples 1 to 5 described later.

Moreover, it is preferable from a viewpoint which exhibits the effect of this invention that the main component of the island part of the said sea island structure is a perfluoropolyether structure site | part.
Here, the main component of the island portion means a component that occupies 80% by mass or more of the island portion. The proportion of the perfluoropolyether structural moiety occupying the island part is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more.

  The average thickness of the antifouling layer is not particularly limited, but is preferably 1 to 30 nm (estimated value), more preferably 1 to 20 nm (estimated value) from the viewpoint of antifouling property and durability.

The antifouling layer contains a perfluoropolyether structure and a siloxane structure. When the antifouling layer contains a perfluoropolyether structure, the surface free energy of the antifouling layer can be reduced to make it difficult to stain.
The perfluoropolyether structure and the siloxane structure are not particularly limited as long as the antifouling layer contains a perfluoropolyether structure and a siloxane structure, but a condensation polymer of alkoxysilane having a perfluoropolyether structure (hereinafter referred to as It is preferred that it is simply referred to as "polycondensate". Here, in the present invention, "having a perfluoropolyether structure" means having a group containing a perfluoropolyether bond.
The polycondensation product is a polycondensation product of an alkoxysilane having a perfluoropolyether structure and a compound having a functional group that reacts with the alkoxy group of the alkoxysilane having a perfluoropolyether structure.
The compound having a functional group reactive with an alkoxy group can be used without particular limitation as long as it has a functional group reactive with an alkoxy group, and examples thereof include an alkoxy group, a carboxyl group, a hydroxyl group and an amino group The compound which has a sulfonic acid group etc. is mentioned. Among them, alkoxysilanes are preferable, and tetraalkoxysilanes are particularly preferable, from the viewpoint of improving the reactivity and the antifouling property.
Hereinafter, a tetraalkoxysilane is illustrated and demonstrated as a compound which has a functional group which reacts with an alkoxy group.

It is preferable from the viewpoint of antifouling property improvement that the condensation product of the alkoxysilane having a perfluoropolyether structure is a condensation product of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane.
When the polycondensation product is a structure in which an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane are polycondensed, an interval between adjacent perfluoropolyether structural sites becomes wide and sparse, and the perfluoropolyether By making the structure site easy to move and flexible, it is possible to improve the slip-off property, to make it even less likely to be soiled, and to make it easy to wipe off the attached soil. Moreover, the island part of the above-mentioned sea-island structure can be made easy to form.
The proportion of the condensation-polymerized material occupying the antifouling layer is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and still more preferably 80 to 100% by mass. .

(Alkoxysilane having a perfluoropolyether structure)
The alkoxysilane which has a perfluoropolyether structure used as a raw material of the said condensation-polymerization thing reduces the surface free energy of an antifouling layer, and makes it hard to attach by having a perfluoropolyether structure. Furthermore, the spacing between adjacent perfluoropolyether structural sites is wide and sparse, and the perfluoropolyether structural sites are easy to move and have flexibility, thereby further reducing the possibility of soiling and wiping off the attached soil. make it easier.
Examples of the alkoxysilane having a perfluoropolyether structure include compounds represented by the following general formulas (2) to (5), and from the viewpoint of antifouling property, it is represented by the following general formula (2) Compounds are preferred.

(Wherein, R ² is an alkyl group having 1 to 6 carbon atoms. However, plural R ^{2 s} may be the same or different. R ^{3 to} R ¹⁰ each independently have 1 to 12 carbon atoms Z ¹ is a 1 to 10 valent organopolysiloxane group having a siloxane bond, Z ² is a 2 to 10 valent organopolysiloxane group having a siloxane bond, and Q is a peroxy group. Rf is a linear or branched perfluoroalkyl group, n is an integer of 1 to 200, and m is an integer of 1 to 10.

As a C1-C6 alkyl group of said R < ² >, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, isopentyl group is mentioned, for example Groups, neopentyl group, n-hexyl group, isohexyl group and the like are mentioned, and in view of antifouling property and reactivity, methyl group and ethyl group are preferable, and methyl group is more preferable.
R ^{3 to} R ¹⁰ each independently represent a divalent organic group having 1 to 12 carbon atoms, preferably 3 to 8 carbon atoms, and specifically, a methylene group, an ethylene group, a propylene group (trimethylene group , Methyl ethylene group), butylene group (tetramethylene group, methyl propylene group), alkylene group such as hexamethylene group, octamethylene group, arylene group such as phenylene group, or a combination of two or more of these groups. Be Also, these groups may contain an ether bond, an amide bond, an ester bond, and a vinyl bond, and may further contain an oxygen atom, a nitrogen atom and a fluorine atom.

The 2-10 divalent organopolysiloxane group having a siloxane bond in the ^{Z 2,} for example, groups represented by the following general formula (6-1) to (6-12).

  Among the groups represented by the above general formulas (6-1) to (6-12), from the viewpoint of obtaining the antifouling property which is the effect of the present invention, general formulas (6-1), (6-2), Groups represented by (6-3), (6-4) and (6-7) are preferred.

The group containing a perfluoropolyether bond of the Q, for _{example, -CF 2 O -, - CF} 2 CF 2 O -, - CF 2 CF 2 CF 2 O -, - CF (CF 3) CF 2 O- _{, -OCF 2 OCF 2 CF 2 -} , - CF 2 CF 2 CF 2 CF 2 O -, - CF 2 CF (CF 3) CF 2 O -, - CF 2 CF 2 CF 2 CF 2 CF 2 CF 2 O- , -C _{(CF 3)} 2 O- and the like.
Among them, from the viewpoint of antifouling _{property, -CF 2 CF 2 O -,} - CF 2 CF 2 CF 2 O -, - CF (CF 3) CF 2 O -, - OCF 2 OCF 2 CF 2 -, - CF 2 _{CF (CF} 3) CF 2 O- are preferred. These may include only one type or two or more types.

Rf is a linear or branched perfluoroalkyl group, and from the viewpoint of obtaining the effects of the present invention, a linear perfluoroalkyl group is preferable.
Examples of the linear perfluoroalkyl group include trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, nonafluorobutyl group, undecafluoropentyl group, tridecafluorohexyl group, etc. As the perfluoroalkyl group of the structure, 1- (trifluoromethyl) -1,2,2,2-tetrafluoroethyl group, 1,1-di (trifluoromethyl) -2,2,2-trifluoroethyl And 2- (trifluoromethyl) -1,1,3,3,3-pentafluoropropyl and the like.

The above n is an integer of 1 to 200, and preferably 2 to 100, more preferably 3 to 60 from the viewpoint of antifouling properties. By setting n to 1 or more, the substrate surface can be sufficiently coated, the surface free energy of the surface of the antifouling layer is reduced, and the antifouling property can be improved. By setting n to 200 or less, the reactivity of the alkoxysilyl group (—Si (OR ² ) ₃ ) can be enhanced.

  The above m is an integer of 1 to 10, and preferably 1 to 7 and more preferably 1 to 5 from the viewpoint of antifouling properties. By setting m to 1 or more, slipperiness is improved, and higher stain resistance can be obtained. By setting m to 10 or less, an increase in surface free energy can be suppressed and a decrease in antifouling property can be suppressed.

The alkoxysilane having a perfluoropolyether structure is preferably trimethoxysilane having a perfluoropolyether structure from the viewpoint of antifouling property and reactivity.
Moreover, as an alkoxysilane which has the said perfluoropolyether structure, Shin-Etsu Chemical Co., Ltd. product "X-71-195", "KY-178", "KY-164", "KY-108", "KP- “911”, Daikin Industries, Ltd. “Optool DSX”, “Optool DSX-E”, etc. are commercially available, and “X-71-195” is preferable from the viewpoint of productivity and antifouling property.

(Tetraalkoxysilane)
Since tetraalkoxysilane has four alkoxy groups, it has high reactivity with the alkoxysilane having the above-mentioned perfluoropolyether structure. As the above tetraalkoxysilane, for example, a compound represented by the following general formula (1) is preferably used.

(Wherein, R ¹ is an alkyl group having 1 to 6 carbon atoms. However, plural R ^{1 s} may be the same or different)

The alkyl group having 1 to 6 carbon atoms of the ^{R 1,} for example, a methyl group, an ethyl group, n- propyl group, an isopropyl group, n- butyl group, an isobutyl group, t- butyl group, n- pentyl group, isopentyl Groups, neopentyl group, n-hexyl group, isohexyl group and the like. Among them, a methyl group and an ethyl group are preferable from the viewpoint of antifouling property and reactivity, and specifically, at least one selected from tetramethoxysilane and tetraethoxysilane is preferable.

[Base material]
As a base material used for the member of the present invention, for example, various inorganic materials such as glass plate, aluminum oxide plate, spin-on-glass (SOG) material, thermoplastic resin, thermosetting resin, ionizing radiation curable resin And various organic resin materials, organic-inorganic composite materials, and the like. Among them, from the viewpoint of reactivity with silane, those having a hydroxyl group on the surface are preferable, and from the viewpoint of the processability of the material, the mechanical strength of the member obtained, and the easiness of formation of the antifouling layer, etc. Glass plates or organic-inorganic composite materials are preferred, and glass plates are more preferred. The glass plate may be chemically strengthened in order to improve the strength. Examples of SOG materials include alkyl siloxane-based materials such as methyl siloxane, hydroxysilsesquioxane-based materials, silazane-based materials, silsesquioxane-based materials, etc. From the viewpoint of durability, etc., silsesquioxane-based materials Is preferred.
As a commercially available SOG material, for example, a coating material “HSG” (trade name, manufactured by Hitachi Chemical Co., Ltd.), an OCN series manufactured by Tokyo Ohka Kogyo Co., Ltd., etc. may be mentioned. Moreover, as organic-inorganic composite material of a commercial item, organic-inorganic composite material (brand name "NH-1000G", Nippon Soda Co., Ltd. product) etc. in which the outermost surface spontaneously mineralizes by UV irradiation are mentioned.
In addition, the shape of the said base material may be planar structure, and may be three-dimensional structure.

The thickness of the glass plate used as the substrate is not particularly limited, but is preferably 0.01 to 100 mm, more preferably 0.02 to 10 mm from the viewpoint of optical properties and durability. The thickness of the resin film used as the substrate is preferably 1 to 500 μm, more preferably 3 to 300 μm, from the viewpoint of strength and optical properties.
A low reflection layer may be formed on the surface of the substrate to improve the optical properties. The low reflective layer can be formed by laminating a plurality of inorganic compounds by sputtering or the like. In addition, on the surface of the base material or the low reflection layer, coating as an anchor agent or a primer is applied, or as an adhesive layer, in order to improve adhesion and improve long-term reliability in the use environment. The inorganic layer may be formed in advance. As the inorganic layer, a silicon compound is preferable, and SiO ₂ and SiO x are more preferable from the viewpoint of adhesiveness and durability. The adhesion layer can be formed by a method such as a vapor deposition method, a sputtering method, an ion plating method, or a chemical vapor deposition method. Further, regardless of the formation of these layers, physical treatments such as corona discharge treatment, oxidation treatment, plasma treatment and the like may be performed in order to improve adhesion.
In addition, from the viewpoint of using as a display or the like, the total light transmittance of the base material is preferably 85% or more, and more preferably 90% or more. The transmittance of the substrate can be measured by a method in accordance with JIS K 7361-1 (Plastic-Test method of total light transmittance of transparent material).

[Method of manufacturing member]
Next, the manufacturing method of the member mentioned above is demonstrated.
The method for producing a member of the present invention is a condensation product obtained by hydrolysis and condensation polymerization of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane in a mixed solvent of an organic solvent, water and an acid And a step (2) of applying the composition to the substrate to form an antifouling layer.

(Step (1))
In this step, for example, an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane are mixed and stirred in a mixed solvent of an organic solvent, water and an acid, and the alkoxysilane having the above-mentioned perfluoropolyether structure is stirred. Hydrolysis of tetraalkoxysilane and subsequent condensation polymerization give a condensation product.
Specifically, after the alkoxy group of the alkoxysilane having the above-mentioned perfluoropolyether structure and the alkoxy group of the above-mentioned tetraalkoxysilane respectively hydrolyze to form a silanol group, the above-mentioned polycondensate can be said perfluoropoly It is obtained by condensation polymerization of a silanol group possessed by an alkoxysilane having an ether structure and a silanol group possessed by the tetraalkoxysilane.

  The hydrolysis and condensation reactions are preferably carried out under a constant atmosphere in which these reactions take place properly. Specifically, it is preferably performed in the range of −25 to 120 ° C. for about 0.1 to 200 hours, more preferably at about −10 to 100 ° C., for about 0.5 to 150 hours, 0 to 70 ° C. It is further preferable to carry out for about 1 to 120 hours. By carrying out the reaction temperature and the reaction time within the above range, the above-mentioned sea-island structure is easily formed, and the above-mentioned conditions (1) to (3) are easily satisfied.

As the alkoxysilane having a perfluoropolyether structure and the tetraalkoxysilane, those described above can be used.
Moreover, the weight average molecular weight of the alkoxysilane which has the said perfluoropolyether structure can be calculated | required by GPC measurement.
The weight ratio of the alkoxysilane having the perfluoropolyether structure to the tetraalkoxysilane is preferably 1: 0.1 to 10.0, more preferably 1: 0.15 to 8.0, still more preferably 1: 0.2 to 6.0. By setting it in the said range, antifouling property can be improved. Moreover, it is easy to form the above-mentioned sea-island structure, and it is easy to satisfy above-mentioned conditions (1)-(3).

From the viewpoint of dissolving the alkoxysilane having the above-mentioned perfluoropolyether structure, a fluorine-based solvent is preferably used as the organic solvent. From the viewpoint of solubility in water, a mixed organic solvent of a fluorine-based solvent and an amphiphilic solvent is preferable.
As the amphiphilic solvent, for example, water-soluble organic solvents such as alcohols and ketones are suitably used. As said alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl- 1-propanol, tertiary butyl alcohol etc. are mentioned, for example. Examples of the ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone and the like. As another water-soluble organic solvent, tetrahydrofuran, dioxane, acetonitrile, ethyl acetate or the like is used. These can be used singly or in combination of two or more.

  The compounding amount of the organic solvent in the composition is preferably 90.000 to 99.999% by mass, more preferably 92.00 to 99.99% by mass, still more preferably 95.0 to 99.9% by mass. . By setting the content to 90.000% by mass or more, the reaction in the mixed solvent can be uniformly progressed, and the antifouling layer formed from the composition can be uniformly transparent, and 99.999% by mass or less By setting it as above, a sufficient antifouling layer can be formed on the substrate surface.

  Examples of water include ion-exchanged water and distilled water. Moreover, the compounding quantity of water contained in the said mixed solvent will not be specifically limited if it is 0.001 mass% or more, Preferably 0.001-1.000 mass%, More preferably, it is 0.005- It mix | blends in the ratio of 0.500 mass%. By setting it as 0.001 mass% or more, the said hydrolysis is accelerated | stimulated and precipitation of the alkoxysilane which has a perfluoropolyether structure can be suppressed by setting it as 1.000 mass% or less.

  The acid is not particularly limited as long as it has the above-mentioned action of promoting hydrolysis, and hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid, succinic acid, acetic acid, formic acid, oxalic acid, citric acid, benzoic acid and the like Hydrochloric acid is preferred from the viewpoint of reactivity and removal from the antifouling layer at the time of drying. Moreover, the compounding quantity of the acid contained in the said mixed solvent becomes like this. Preferably it is 0.000001-10.000000 mass%, More preferably 0.00001-5.00000 mass%, from a viewpoint of promoting the said hydrolysis. More preferably, it is 0.0001 to 1.0000 mass%.

In the above composition, in addition to the above components, a photoacid generator, a photobase generator and the like generally compounded in this type of composition may be added as needed, as long as the effects of the present invention are not impaired. can do. By incorporating the photoacid generator or the photobase generator, a stronger antifouling layer can be formed.
Moreover, solid content concentration of the said composition becomes like this. Preferably it is 0.01-15.00 mass%, More preferably, it is 0.05-10.00 mass%, More preferably, it is 0.1-5.0 mass% . By setting the content to 0.01% by mass or more, the curing of the antifouling layer can be promoted, and by setting the content to 15.00% by mass or less, the coloring of the antifouling layer and the reduction of the antifouling property can be suppressed. it can.

(Step (2))
The composition prepared in the above step (1) is applied onto a substrate, dried and cured to form an antifouling layer.
The method of applying the composition may be any method as long as it can uniformly apply a desired thickness, and may be appropriately selected from conventionally known methods. For example, a gravure coating method, a knife coating method, a dip coating method, a spray coating method, an air knife coating method, a spin coating method, a roll coating method, a curtain coating method, a die coating method, a casting method, a bar coating method, an extrusion coating method, etc. Can be mentioned.

  Although the setting conditions of the drying process of the film formed by applying the composition described above vary depending on the raw material, the solvent, and the temperature and humidity of the atmosphere, they are controlled under a constant atmosphere suitable for obtaining the effects of the present invention It is preferable to do in the situation. For example, it is usually preferable to carry out at room temperature (25 ° C.) to 300 ° C. for about 0.1 to 48 hours, and more preferable at 25 to 250 ° C. for about 0.2 to 24 hours. These treatments may be completed under one atmosphere, or may be treated stepwise under two or more atmospheres.

[Evaluation of members]
In the antifouling layer, in order to make it difficult to be soiled, it has been studied to increase the contact angle between water and fat and oil. On the other hand, in the present invention, by increasing the contact angle between water and fat and reducing the sliding angle between the two, high sliding property is obtained, so that it is difficult to get dirty and dirt that has been attached. It is easy to wipe off.
The sliding property can be evaluated by measuring the sliding angle of pure water and n-hexadecane, and the smaller the sliding angle, the better the sliding property. For the sliding angle, 10 μL of pure water and 3 μL of n-hexadecane are dropped in a horizontal state on the antifouling layer surface of the member to be measured, and the member is gradually inclined to make the droplet start to slip It is determined by measuring (slip angle). As a measuring device, for example, a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd. can be used. The sliding angle can be measured specifically by the method described in the examples.

The member of the present invention preferably has a contact angle of pure water on the surface of the antifouling layer of 95 ° or more, more preferably 112 ° or more, and still more preferably 114 ° or more. The sliding angle of pure water on the surface of the antifouling layer is preferably 30 ° or less, more preferably 15 ° or less, and still more preferably less than 8 °.
When the contact angle is 95 ° or more, it is indicated that the antifouling layer has low surface free energy, and it is possible to make the soiling difficult. In addition, when the sliding angle is 30 ° or less, the sliding property of the surface of the antifouling layer is improved, and it is possible to make it difficult to stain and to easily wipe off the attached stain.
In the present invention, the reason why the contact angle can be 95 ° or more is considered to be due to the fact that the above-mentioned condensation-polymerized product has a perfluoropolyether structural site. Further, the sliding angle can be set to 30 ° or less because the condensation polymer is a structure in which an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane are condensation-polymerized. It is believed that the space between the polyether structural sites is wide and sparse, and the perfluoropolyether structural sites are easy to move and have flexibility.
The contact angle is measured by the θ / 2 method with respect to pure water and n-hexadecane using a contact angle measurement device (for example, contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd.). It is determined by The contact angle can be measured specifically by the method described in the examples.

  In the member of the present invention, the contact angle of n-hexadecane on the surface of the antifouling layer is preferably 50 ° or more, more preferably 55 ° or more, and still more preferably 60 ° or more. The sliding angle of n-hexadecane on the surface of the antifouling layer is preferably 15 ° or less, more preferably 10 ° or less, and still more preferably 6 ° or less.

The inventors of the present invention found that the antifouling layer contains a condensation polymer of alkoxysilane having a perfluoropolyether structure and tetraalkoxysilane, so that the coefficient of friction between the surface of the antifouling layer and the cloth used for fingers and wiping etc. Was found to be smaller and to improve the slipperiness. The member of the present invention reduces the surface free energy of the antifouling layer by increasing the contact angle between water and fat and oil, and in addition to the fact that high slipping property is obtained by reducing the sliding angle between water and fat and oil. By obtaining high slipperiness, it is more difficult for the surface of the antifouling layer to be soiled (with less fingerprint adhesion) and easier to wipe off the soiled with it (fingerprint wiping performance is good). it can.
As described above, the member of the present invention has extremely excellent antifouling property which can not be obtained by the conventional antifouling member, because the interval between adjacent perfluoropolyether structural sites possessed by the above-mentioned polycondensation product is wide and sparse. It is believed that this results from the fact that the perfluoropolyether structural moiety is flexible and flexible.
In particular, in order to obtain the antifouling property of the surface used by sliding with a finger such as a touch panel, the improvement of the above-mentioned slipperiness is important.
In the present invention, “slip” is an index representing the smoothness of the surface of the antifouling layer of a member. The slipperiness can be evaluated specifically by the method described in the examples.

  The member of the present invention is excellent in anti-staining property, and therefore, when it is touched by hand, stains such as fingerprints, sebum and sweat are easily attached to the surface, for example, liquid crystal display, plasma display, organic / inorganic EL display, electronic Paper, image display devices such as VFDs and EPDs, touch panels, portable electronic devices such as mobile phones and music players, optical recording media such as CDs, DVDs and Blu-ray discs, window glass such as cars, trains and aircrafts, building materials for outer walls It is suitably used as an inner wall of wallpaper, etc., as a surface material of home appliances, car panels and the like.

<Touch panel / image display device>
The touch panel of the present invention is provided with the above-mentioned member.
Examples of the touch panel include a capacitive touch panel, a resistive touch panel, an optical touch panel, an ultrasonic touch panel, and an electromagnetic induction touch panel. The touch panel may be on-cell or in-cell.
The touch panel of the present invention can be used, for example, in various image display devices provided with the member of the present invention as a surface material. In addition, the said member can be used suitably as an antifouling film used for the image display part surface of various image display apparatuses.

Hereinafter, the present invention will be specifically described by way of examples and comparative examples. In addition, this invention is not limited to the form as described in an Example.
Evaluation of the member of an Example and a comparative example was performed as follows.

(1) Shape of antifouling layer surface <SRa, SRsk, SRz>
The measurement and analysis of the shape of the antifouling layer surface of each member obtained in Examples and Comparative Examples were performed using a white interference microscope (New View 7300, manufactured by Zygo). The results are shown in Table 1.
In addition, Microscope Application of Metro Pro Version 9.0.10 64-bit was used for measurement and analysis software.
(Measurement condition)
Objective lens: 100 × Zoom: 2 × Measurement area: 50 μm × 50 μm
Resolution (spacing per point): 0.57 μm
(Analysis conditions)
Removed: Plane
Filter: OFF
FilterType: OFF
Low wavelength: OFF
High wavelength: OFF
Remove spikes: OFF
Spike Height (xRMS): OFF
<Half width half width>
Soft: Atomic force microscope (AFM) SPM-9600 manufactured by Shimadzu Corporation Soft: Shape of the surface of the antifouling layer of each member obtained in the example in the on-line (measurement) mode in the SPM manager Were measured to obtain histogram data of height distribution. After that, inclination correction processing was performed using the off-line (analysis) mode to obtain a gray scale image when height: 0 nm is black and height: 25 nm or more is white (vertical: 512 × horizontal: 512 = 262144 pixels). The image was subjected to image analysis using Photoshop (registered trademark). Histogram data of height distribution was obtained when the density of each pixel of each image was 256 tones (black: 0, white: 255), and the half width half width (w) was calculated. The results are shown in Table 1. FIG. 2 is histogram data of the height distribution of the third embodiment.
(AFM measurement conditions)
Measurement mode: Phase scanning range: 10 μm × 10 μm,
Scanning speed: 0.8 to 1 Hz
Number of pixels: 512 × 512
Used cantilever: Nano World NCHR (resonance frequency: 320 kHz, spring constant 42 N / m)
(AFM analysis conditions)
Inclination correction: line fit <proportion of island part in sea-island structure>
The ratio of islands in the sea-island structure is as follows: After calculating the average value of height data of the surface of the antifouling layer by measuring the shape of the surface of the antifouling layer by AFM, [the number of measurement points having a height greater than the average Calculated by × 100 / number of all measurements], 20 points were measured, and the average of the measured 20 points was calculated. The results are shown in Table 1.
(2) Measurement of Contact Angle The contact angle of pure water and n-hexadecane was measured using a contact angle meter “DM 500” manufactured by Kyowa Interface Science Co., Ltd. 1.5 μL of pure water is dropped on the surface of the antifouling layer of the member, and one second after droplet deposition, the contact angle from the angle to the solid surface of the straight line connecting the left and right end points of the dropped droplet and the vertex according to the θ / 2 method Was calculated. The average value measured five times was taken as the value of the contact angle. The results are shown in Table 2.
(3) Surface Free Energy From the measurement results of the contact angle, the surface free energy was evaluated according to the following criteria. The larger the contact angle, the lower the surface free energy, and the better. The results are shown in Table 2.
:: pure water 110 ° or more and n-hexadecane 60 ° or more ○: pure water 110 ° to 95 ° or more and n-hexadecane 60 ° to 50 ° or more x: pure water 95 ° or n-hexadecane 50 ° (4) Measurement of sliding angle The sliding angle of pure water and n-hexadecane was measured using a contact angle meter "DM 500" manufactured by Kyowa Interface Science Co., Ltd. The member is placed horizontally, 10 μL of pure water and 3 μL of n-hexadecane are dropped respectively on the antifouling layer surface of the member, the member is gradually inclined, and the inclination angle at which the droplet starts to slip (slip angle) Was measured. The average value measured five times was taken as the value of the sliding angle. The results are shown in Table 2.
(5) Sliding property From the measurement result of the said sliding angle, sliding property was evaluated by the following references | standards. The smaller the sliding angle, the better the sliding property. The results are shown in Table 2.
:: less than 15 ° of pure water and less than 10 ° of n-hexadecane ○: more than 15 ° to 30 ° of pure water, or 10 ° to 15 ° of n-hexadecane x: more than 30 ° for pure water or more than 15 ° of n-hexadecane (6) Evaluation of slipperiness Ten test subjects have their fingers in contact with the antifouling layer surface of each member prepared in Examples 1 to 5 and Comparative Example 1, and the fingers are in the lateral direction parallel to the antifouling layer surface. Reciprocated (moving like sliding on a smartphone). The tactile sensation due to the friction between the finger and the antifouling layer surface at that time was judged according to the following evaluation criteria, and the average value of 10 subjects was determined. This average value was judged according to the following judgment standard. The results are shown in Table 2.
<Evaluation criteria>
5 points: always smooth 3 points: smooth 0 points: bad <criteria>
○: 4.4 points or more Δ: 2.1 points or more and less than 4.4 points ×: 2.1 points or less (7) Fingerprint attachment Artificial fingerprint liquid (Isehisa (stock) on a silicone resin plate (10 mmφ × 30 mm column shape) Made to adhere to JIS C9606 Annex 4) pressed onto the surface of the antifouling layer of the member to adhere a fingerprint. The adhesion state of the fingerprint was visually observed and evaluated according to the following criteria. The results are shown in Table 2.
:: Strongly repels fingerprints and has a very small amount of adhesion ○: Repels fingerprints and has a small amount of adhesion Δ: Repel fingerprints but adheres x: Fingerprints are widely attached (8) Fingerprint wipeability A fingerprint obtained by attaching an artificial fingerprint liquid (made by Isehisa Co., Ltd., JIS C9606 Annex 4) to a silicone resin plate (10 mmφ × 30 mm column shape) is pressed against the surface of the antifouling layer of the member The The attached fingerprints were wiped off with Ben Cotton, manufactured by Asahi Kasei Co., Ltd., and the remaining traces of the fingerprints were visually observed and evaluated according to the following criteria. The results are shown in Table 2.
:: up to 3 times of wiping, fingerprint adhesion mark not completely visible ○: 4 to 7 times wiping, fingerprint adhesion mark not completely visible Δ: 8 to 10 times wiping , The fingerprint marks are not completely visible. ×: The fingerprint marks are clearly visible after 10 wipes.

Example 1
(Preparation of composition)
20.2 g of a fluorine-based organic solvent (3M, trade name: Novec 7300), 3.5 g of an amphiphilic solvent (Kanto Chemical Co., Ltd., trade name: 2-propanol), and a perfluoropolyether structure Alkoxysilane solution (Shin-Etsu Chemical Co., Ltd. product name, "X-71-195", solid content 20%) 0.75 g and tetraalkoxysilane (Tokyo Chemical Industry Co., Ltd. product name, trade name: orthosilic acid In a mixed solution of 0.051 g of tetramethyl), 3.8 mg of water and 22.4 mg of 1 M hydrochloric acid are added, and the mixture is stirred at 25 ° C. for 3 hours, and an alkoxysilane having a perfluoropolyether structure and tetra Composition 1 containing a condensation polymer with an alkoxysilane was obtained.
(Manufacturing of members)
The composition 1 is coated on a glass substrate (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA-10G, thickness 700 μm) using a spin coater at a rotational speed of 3000 rpm, and a coating is applied. It formed. The coated film was dried at room temperature (25 ° C.) for 12 hours, the solvent was removed, and the coating was cured to obtain a member having an average film thickness of 10 nm (estimated value).

Example 2
28.1 g of a fluorine-based organic solvent (3M, trade name: Novec 7300), 4.8 g of an amphiphilic solvent (Kanto Chemical Co., Ltd., trade name: 2-propanol), having a perfluoropolyether structure 0.15 g of an alkoxysilane solution (Shin-Etsu Chemical Co., Ltd., trade name “X-71-195, solid content 20%), tetraalkoxysilane (Tokyo Chemical Industry Co., Ltd., trade name: orthosilicic acid) A member was obtained in the same manner as Example 1, except that 0.076 g of tetramethyl), 5.9 mg of water and 31.1 mg of 1 M hydrochloric acid were used, and the stirring time of the obtained mixed solution was changed to 1.5 hours.

Example 3
A member was obtained in the same manner as Example 2, except that the stirring time of the mixed solution was changed to 3 hours.
An AFM observation image of the surface of the antifouling layer of the obtained member is shown in FIG. When the AFM observation image was analyzed, the shape of the surface of the antifouling layer was a sea-island structure in which a discontinuous projection-like structure having a diameter of about 250 to 500 nm and a height of about 10 to 20 nm was observed.

Example 4
A member was obtained in the same manner as Example 2, except that the stirring time of the mixed solution was changed to 24 hours.

Example 5
A member was obtained in the same manner as Example 2, except that the stirring time of the mixed solution was changed to 72 hours.

Comparative Example 1
23.0 g of a fluorine-based organic solvent (3M, trade name: Novec 7300), 3.9 g of an amphiphilic solvent (Kanto Chemical Co., Ltd., trade name: 2-propanol), tetraalkoxysilane (Tokyo Kasei Kogyo Co., Ltd.) 5.0 mg of water and 25.4 mg of 1 M hydrochloric acid are added to a mixed solution of 0.063 g of trade name: tetramethyl orthosilicate, and stirred at room temperature (25 ° C.) for 3 hours did. The obtained solution is spin-coated on a glass substrate (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA-10G, thickness 700 μm), and allowed to stand at room temperature (25 ° C.) for 1 day to obtain an average film thickness of 10 nm. A member of (estimated value) was obtained.

(Summary of results)
As shown in Table 2, in Examples 1 to 5 in which the antifouling layer contains a perfluoropolyether structure and a siloxane structure, and in which the three-dimensional skewness SRsk of the antifouling layer surface satisfies a specific condition, pure water contacts The angle was 112 to 116 °, and the contact angle of n-hexadecane was 66 to 67 °, both of which had excellent surface free energy low. Further, the sliding angle of pure water is 3 to 20 °, and the sliding angle of n-hexadecane is 2 to 6 °, and the sliding property is good in all cases, and the evaluation of the sliding property is also high. From these results, it was found that the members of Examples 1 to 5 were all difficult to attach a fingerprint, and were excellent in the wipeability of the fingerprint.
On the other hand, in Comparative Example 1 in which the antifouling layer does not contain a perfluoropolyether structure, the three-dimensional skewness SRsk of the antifouling layer surface is -0.325 and does not satisfy the specific conditions of the present invention, and the surface free energy is high. The evaluations of slipperiness and slipperiness were poor, and the evaluations of fingerprint adhesion and fingerprint wiping were inferior as compared with the examples.

  Since the member of the present invention is excellent in antifouling property, it can be suitably used particularly for a portable electronic device having a touch panel display.

Claims (11)

A member having an antifouling layer formed on a substrate, wherein the antifouling layer comprises a perfluoropolyether structure and a siloxane structure, and the three-dimensional skewness SRsk of the surface of the antifouling layer is as described below A member satisfying the condition (1).
0 <SRsk (1) The member according to claim 1, wherein the three-dimensional arithmetic mean roughness SRa of the antifouling layer surface satisfies the following condition (2).
0.3 nm ≦ SRa ≦ 3.0 nm (2) The member according to claim 1 or 2, wherein the three-dimensional ten-point average roughness SRz of the antifouling layer surface satisfies the following condition (3).
SRz ≦ 20.0 nm (3)   The member according to any one of claims 1 to 3, wherein the antifouling layer is formed by a sea-island structure.   The member according to claim 4, wherein the proportion of island portions in the sea-island structure is 25 to 90%.   The member according to any one of claims 1 to 5, wherein the perfluoropolyether structure and the siloxane structure are condensation polymers of alkoxysilanes having a perfluoropolyether structure.   The member according to claim 6, wherein the condensation product of the alkoxysilane having a perfluoropolyether structure is a condensation product of an alkoxysilane having a perfluoropolyether structure and a tetraalkoxysilane. The member according to claim 7, wherein a weight ratio of the alkoxysilane having a perfluoropolyether structure to the tetraalkoxysilane is 1: 0.1 to 10.0. The member according to any one of claims 4 to 8 , wherein the main component of the island portion of the sea-island structure is a perfluoropolyether structural site. A touch panel comprising the member according to any one of claims 1 to 9 . The image display apparatus provided with the touch panel of Claim 10 .