Water-repellent structure and composition for forming water-repellent layer

Abstract

The present disclosure provides a water-repellent structure having a non-fluorine-based water-repellent layer, in which the non-fluorine-based water-repellent layer has good water repellency in an initial state, and has wear resistance in which the water repellency is reduced little even if the surface is rubbed repeatedly. A water-repellent structure (1) having a substrate (10) and a water-repellent film (20) formed on the surface of the substrate (10), in which the water-repellent film (20) contains a water-repellent layer (20) that contains siloxane bonds and one or more organic groups bonded to Si atoms but does not contain fluorine atoms, and the surface (21S) of the water-repellent layer (20) has an elastic modulus distribution. In an arbitrarily selected micron region of 1 [mu] m < 2 >, a high elastic modulus portion having an elastic modulus of 6.0 GPa or more and a low elastic modulus portion having an elastic modulus of 4.0 GPa or less are provided, and the root-mean-square slope of the surface elastic modulus of the micron region is 3.5 GPa or more.

Description

Technical Field

[0001] The present disclosure relates to a water-repellent structure and a composition for forming a water-repellent layer. Background Art

[0002] In window glass applications for transportation equipment such as automobiles, there is known a glass laminate having a water-repellent film formed on the outer surface of a glass plate in order to prevent adhesion of rain, frost, ice, snow, etc. and maintain a clear field of vision.

[0003] In this specification, a structure including a substrate such as a glass plate and a water-repellent film formed on the surface of the substrate is referred to as a "water-repellent structure".

[0004] The water-repellent film includes a water-repellent layer and may include one or more other layers as needed. The water-repellent film may have a base layer under the water-repellent layer, for example. The surface of the water-repellent layer is exposed, and the surface of the water-repellent layer is the outermost surface of the water-repellent film and is the water-repellent surface.

[0005] In the past, fluorine compounds were generally used as materials for water-repellent layers. However, in recent years, the impact of some fluorine compounds such as C6 fluorine compounds on the environment has caused concerns, and therefore, the development of non-fluorine compositions that do not contain fluorine compounds is being promoted as compositions for forming water-repellent layers.

[0006] The water-repellent layer preferably has good water repellency in the initial state and has durability to maintain good water repellency even after long-term use. One example of durability is abrasion resistance.

[0007] For example, in applications such as automobile side window glass, a glass laminate including a glass plate and a water-repellent film can be raised and lowered to open and close the window. In this application, the water-repellent film preferably has abrasion resistance such that water repellency decreases less even when the surface is repeatedly rubbed.

[0008] The applicant disclosed in Patent Document 1 a non-fluorine-based water-repellent layer-forming composition containing one or more hydrolyzable silicon compounds, and a water-repellent structure having a water-repellent film including a water-repellent layer formed using the composition (claims 1, 10, etc.).

[0009] The water-repellent layer disclosed in Patent Document 1 is excellent in water repellency and abrasion resistance.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Application Publication No. 2015-145463 Summary of the invention

[0013] Technical problem to be solved by the invention

[0014] The present inventors have conducted in-depth research on the structure of the micrometer region on the surface of the water-repellent layer using an atomic force microscope (AFM), and invented a non-fluorine-based water-repellent layer having higher abrasion resistance than the water-repellent layer disclosed in Patent Document 1 and a composition for forming the same.

[0015] An object of the present disclosure is to provide a water-repellent structure having a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little decrease in water repellency even when the surface is repeatedly rubbed.

[0016] Another object of the present disclosure is to provide a composition for forming a water-repellent layer capable of forming a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little decrease in water repellency even when the surface is repeatedly rubbed.

[0017] Technical solutions adopted to solve technical problems

[0018] The present disclosure provides the following water-repellent structure and water-repellent layer-forming composition.

[0019] [1] A water-repellent structure comprising a substrate and a water-repellent film formed on a surface of the substrate, wherein:

[0020] The water-repellent film comprises a water-repellent layer containing a siloxane bond and one or more organic groups bonded to Si atoms but containing no fluorine atoms.

[0021] The surface of the water-repellent layer is the outermost surface of the water-repellent film,

[0022] The surface of the water-repellent layer has an elastic modulus distribution, including a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region is above 3.5 GPa.

[0023] [2] The water-repellent structure according to [1], wherein the root mean square slope of the surface elastic modulus of the micrometer region is 35.0 GPa or less.

[0024] [3] The water-repellent structure according to [1] or [2], wherein the at least one organic group is selected from an alkyl group and an alkylene group.

[0025] [4] The water-repellent structure according to any one of [1] to [3], wherein the average elastic modulus of the micron region on the surface of the water-repellent layer is 2.0 to 14.0 GPa.

[0026] [5] A water-repellent structure as described in any one of [1] to [4], wherein, in the micron region on the surface of the water-repellent layer, the area ratio of the high elastic modulus region with an elastic modulus of more than 6.0 GPa is 1 to 50%, and the area ratio of the low elastic modulus region with an elastic modulus of less than 4.0 GPa is 10 to 80%.

[0027] [6] The water-repellent structure according to any one of [1] to [5], wherein the initial water contact angle of the surface of the water-repellent layer is 90° or more

[0028] [7] A water-repellent structure as described in any one of [1] to [6], wherein the water-repellent layer is a dried solid product of the following composition, the composition comprising a plurality of hydrolyzable silicon compounds and one or more organic solvents, the plurality of hydrolyzable silicon compounds comprising one or more hydrolyzable silicones having a hydrolyzable group and one or more hydrolyzable alkyl silanes having a hydrolyzable group and an alkyl group, and the same type or different types can be partially hydrolyzed and condensed, the amount of the one or more hydrolyzable alkyl silanes is 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable silicones and the one or more hydrolyzable alkyl silanes, and the one or more organic solvents have a solubility parameter (HSP) value based on the Hansen definition of 10.8 to 12.1.

[0029] [8] The water-repellent structure according to [7], wherein the hydrolyzable silicone is a compound represented by the following formula (1), and the hydrolyzable alkylsilane is a compound represented by the following formula (2).

[0030] R 13 -(SiR 12 2O) k1 -SiR 12 2-Y 1 -Si(R 11 ) 3-n1 (X 1 ) n1 ……(1)

[0031] (In the above formula, R 13 is an alkyl group having 1 to 30 carbon atoms, R 12 are independently an alkyl group having less than 3 carbon atoms, Y 1 is an alkylene group having 2 to 4 carbon atoms or an oxygen atom, R 11 are independently a monovalent hydrocarbon group, X 1 are independently hydrolyzable groups, X 1 It can be hydrolyzed to form a hydroxyl group, k1 is an integer from 10 to 300, and n1 is an integer from 1 to 3.)

[0032] R 22 -Si(R21 ) 3-n2 (X 2 ) n2 ……(2)

[0033] (In the above formula, R 22 is an alkyl group having 1 to 30 carbon atoms, R 21 are independently a monovalent hydrocarbon group, X 2 are independently hydrolyzable groups, X 2 It can be hydrolyzed to form a hydroxyl group, and n2 is an integer from 1 to 3.

[0034] [9] The water-repellent structure according to any one of [1] to [8], wherein the water-repellent film has an underlayer containing siloxane bonds but no fluorine atoms under the water-repellent layer.

[0035]

[10] The water-repellent structure as described in [9], wherein the base layer is a dried solidified product of a composition comprising one or more hydrolyzable silicon compounds selected from the compound represented by the following formula (3) and the compound represented by the following formula (4), and which can be partially hydrolyzed and condensed between the same type or different types.

[0036] Si(X 3 )4……(3)

[0037] (In the above formula, X 3 are independently hydrolyzable groups, X 3 Can be hydrolyzed to form hydroxyl groups.)

[0038] X 4 3Si-(CH2) m -SiX 4 3……(4)

[0039] (In the above formula, X 4 are independently hydrolyzable groups, X 4 It can be hydrolyzed to form a hydroxyl group, and m is an integer of 1 to 8.

[0040]

[11] The water-repellent structure according to any one of [1] to

[10] , wherein the substrate comprises a glass plate.

[0041]

[12] A composition for forming a water-repellent layer, comprising a plurality of hydrolyzable silicon compounds and one or more organic solvents, wherein the plurality of hydrolyzable silicon compounds comprise one or more hydrolyzable silicones having a hydrolyzable group and one or more hydrolyzable alkylsilanes having a hydrolyzable group and an alkyl group, and the same or different types can be partially hydrolyzed and condensed, the amount of the one or more hydrolyzable alkylsilanes is 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable silicones and the one or more hydrolyzable alkylsilanes, and the one or more organic solvents have a solubility parameter based on the Hansen definition, i.e., an HSP value of 10.8 to 12.1.

[0042]

[13] The water-repellent layer-forming composition according to

[12] , wherein the hydrolyzable silicone is a compound represented by the following formula (1), and the hydrolyzable alkylsilane is a compound represented by the following formula (2).

[0043] R 13 -(SiR 12 2O) k1 -SiR 12 2-Y 1 -Si(R 11 ) 3-n1 (X 1 ) n1 ……(1)

[0044] (In the above formula, R 13 is an alkyl group having 1 to 30 carbon atoms, R 12 are independently an alkyl group having less than 3 carbon atoms, Y 1 is an alkylene group having 2 to 4 carbon atoms or an oxygen atom, R 11 are independently a monovalent hydrocarbon group, X 1 are independently hydrolyzable groups, X 1 It can be hydrolyzed to form a hydroxyl group, k1 is an integer from 10 to 300, and n1 is an integer from 1 to 3.)

[0045] R 22 -Si(R 21 ) 3-n2 (X 2 ) n2 ……(2)

[0046] (In the above formula, R 22 is an alkyl group having 1 to 30 carbon atoms, R 21 are independently a monovalent hydrocarbon group, X 2 are independently hydrolyzable groups, X 2 It can be hydrolyzed to form a hydroxyl group, and n2 is an integer from 1 to 3.

[0047]

[14] A composition for forming a water-repellent layer as described in

[12] or

[13] , which is used to form a water-repellent layer, wherein the surface of the water-repellent layer has an elastic modulus distribution, and has a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region is above 3.5 GPa.

[0048] Effects of the Invention

[0049] The water-repellent layer included in the water-repellent structure of the present disclosure has a specific elastic modulus distribution, and can have abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed.

[0050] According to the present disclosure, it is possible to provide a water-repellent structure having a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed.

[0051] According to the present disclosure, a water-repellent layer-forming composition capable of forming a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic cross-sectional view of the water-repellent structure according to the first embodiment of the present invention.

[0053] Figure 2 It is a schematic cross-sectional view of a water-repellent structure according to a second embodiment of the present invention.

[0054] Figure 3 This is an image of the elastic modulus of the micrometer region of the water-repellent layer obtained in Example 3.

[0055] Figure 4 This is an image of the elastic modulus of the micrometer region of the water-repellent layer obtained in Example 61. DETAILED DESCRIPTION

[0056] In this specification, unless otherwise specified, the "surface" of a planar body such as a plate, a sheet, or a film refers to a main surface having a large area.

[0057] In the present specification, a compound represented by any formula (x) is also referred to as compound (x).

[0058] In the chemical formula, Me represents methyl, Et represents ethyl, n Bu represents n-butyl.

[0059] In a composition containing one or more hydrolyzable silicon compounds, one or more hydrolyzable silicon compounds may be partially hydrolyzed and condensed between the same type or between different types.

[0060] In the present specification, the hydrolysis-condensation product of one or more hydrolyzable silicon compounds refers to an oligomer (polymer) generated by hydrolysis of at least a part of the hydrolyzable groups contained in the one or more hydrolyzable silicon compounds and subsequent dehydration condensation.

[0061] In the present specification, unless otherwise specified, "to" indicating a numerical range is used to mean that the numerical values ​​described before and after it are included as the lower limit and the upper limit.

[0062] Hereinafter, embodiments of the present invention will be described.

[0063] [Water-repellent structure]

[0064] The water-repellent structure disclosed herein has a substrate and a water-repellent film formed on the surface of the substrate.

[0065] The water-repellent film includes a water-repellent layer and may include one or more other layers as necessary. In other words, the water-repellent film may have a single-layer structure consisting only of the water-repellent layer, or may have a laminated structure of the water-repellent layer and one or more other layers.

[0066] The water-repellent film may have, for example, a base layer below the water-repellent layer. The water-repellent film may have one or more intermediate layers between the water-repellent layer and the base layer.

[0067] The surface of the water-repellent layer is exposed, and the surface of the water-repellent layer is the outermost surface of the water-repellent film and is the water-repellent surface.

[0068] The water-repellent film is formed on at least a portion of the surface of the substrate.

[0069] In the water-repellent structure of the present disclosure, the water-repellent layer is a siloxane-based inorganic layer containing siloxane bonds (Si—O bonds) and one or more organic groups bonded to Si atoms, but containing no fluorine atoms. The one or more organic groups can be selected from, for example, alkyl groups and alkylene groups.

[0070] The base layer that may be included in the water-repellent structure of the present disclosure may be a siloxane-based inorganic layer containing a siloxane bond (Si—O bond) but no fluorine atom. The base layer may contain one or more organic groups bonded to Si atoms.

[0071] The water-repellent layer and / or the base layer may contain one or more organic substances.

[0072] Figure 11 is a schematic cross-sectional view of a water-repellent structure according to a first embodiment of the present invention. The water-repellent structure 1 according to the first embodiment has a plate-like substrate 10 and a water-repellent film 20 formed on one surface of the substrate 10. The water-repellent film 20 is composed only of a water-repellent layer 21, and a surface 21S exposed by the water-repellent layer 21 is the outermost surface 20S of the water-repellent film 20. The water-repellent film 20 may also be formed on both surfaces of the substrate 10.

[0073] Figure 2 Schematic cross-sectional view of a water-repellent structure of a second embodiment of the present invention. The water-repellent structure 2 of the second embodiment has a plate-like substrate 10 and a water-repellent film 30 formed on one surface of the substrate 10. The water-repellent film 30 is composed of a water-repellent layer 31 and a base layer 32 formed thereunder, and a surface 31S exposed by the water-repellent layer 31 is the outermost surface 30S of the water-repellent film 30. The water-repellent film 30 may also be formed on both surfaces of the substrate 10.

[0074] In the water-repellent structure disclosed herein, the surface of the water-repellent layer has an elastic modulus distribution including a high elastic modulus portion having an elastic modulus of 6.0 GPa or more and a low elastic modulus portion having an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square.

[0075] The root mean square slope of the surface elastic modulus of the micrometer region is above 3.5 GPa.

[0076] The upper limit of the root mean square slope of the surface elastic modulus of the micrometer region is not particularly limited, but is preferably 35.0 GPa or less, and more preferably 30.0 GPa or less.

[0077] The average elastic modulus of the micrometer region is not particularly limited, but is preferably 2.0 to 14.0 GPa.

[0078] In the micron region, the area ratio of the high elastic modulus region having an elastic modulus of 6.0 GPa or more is preferably 1 to 50%.

[0079] In the micrometer region, the area ratio of the low elastic modulus region having an elastic modulus of 4.0 GPa or less is preferably 10 to 80%.

[0080] The elastic modulus distribution measurement (also called elastic modulus mapping) can be performed, for example, by the Bimodal AFM method, for example, using an atomic force microscope manufactured by Oxford Instruments and one of its accessories, the AM-FM viscoelastic imaging mode.

[0081] Atomic force microscopy (AFM) is a scanning probe microscope that detects the forces between sample atoms and probe atoms. The probe includes a substrate, a cantilever (cantilever spring) extending from the substrate, and a probe mounted on the tip of the cantilever. By changing the distance between the sample and the probe and measuring the force (deflection) acting on the cantilever, a curve can be obtained that plots the relationship between the distance between the sample and the probe and the force (deflection) acting on the cantilever, i.e., a force curve. By analyzing this force curve, the elastic modulus distribution of the sample surface can be obtained.

[0082] Since the measured value may vary depending on the probe, laser spot position, detector, etc. used, it is preferable to keep the measurement conditions unchanged in order to ensure the reproducibility of the data.

[0083] As an atomic force microscope (AFM), an atomic force microscope that adopts photothermal excitation technology to achieve stable probe vibration is preferred. As a substrate used for calculating the optical lever sensitivity (InvOLS), a sapphire substrate whose substrate surface height is adjusted to be equal to the height of the evaluation sample surface is preferred. In order to keep the tip shape parameters unchanged, as a probe, a single crystal diamond probe with a small change in contact state caused by wear is preferred. As an elastic modulus standard used for calculating the tip shape parameters, a polystyrene standard sample (elastic modulus of 2.7 GPa) with an elastic modulus level close to that of the evaluation sample is preferred. The new probe is preferably used for elastic modulus distribution measurement after being used to a certain extent, such as performing surface shape measurements on a 10 μm square smooth glass surface for about 20 times at 1 Hz. The sample surface height of the evaluation sample is preferably within 1 mm and as close to the same height as possible.

[0084] Use AFM to observe the surface of water-repellent layer, the elastic modulus distribution of observation image can be shown with the depth of color.In the image (also referred to as elastic modulus image) showing elastic modulus distribution, the part with high elastic modulus is shown in white, and the part with low elastic modulus is shown in dark color.Use AFM to measure the area ratio of the elastic modulus in the high elastic modulus region above 6.0GPa, the area ratio of the elastic modulus in the low elastic modulus region below 4.0GPa, the root mean square slope of the surface elastic modulus and the average elastic modulus in the observation image.

[0085] In this specification, "an arbitrarily selected micrometer area of ​​1 μm square satisfies a certain specific regulation" means that among 10 arbitrarily selected AFM observation images of 1 μm square, at least 1 AFM observation image satisfies the above regulation. Among 10 arbitrarily selected AFM observation images of 1 μm square, preferably at least 5 AFM observation images satisfy the above regulation. Among 10 arbitrarily selected AFM observation images of 1 μm square, more preferably at least 8 AFM observation images satisfy the above regulation. Among 10 arbitrarily selected AFM observation images of 1 μm square, it is particularly preferred that all AFM observation images satisfy the above regulation.

[0086] "Water repellency" includes static water repellency, which is a property that water droplets are not easy to adhere to, and dynamic water repellency (also called water sliding property), which is a property that water droplets are easy to roll off. The water-repellent layer preferably has excellent static water repellency and dynamic water repellency. Static water repellency can be evaluated by water contact angle, and dynamic water repellency (water sliding property) can be evaluated by water roll-off angle.

[0087] The water-repellent layer preferably has good water repellency in the initial state and has durability to maintain good water repellency even after long-term use. One example of durability is abrasion resistance.

[0088] For example, in applications such as side window glass of an automobile, a glass laminate (water-repellent structure) composed of a glass plate and a water-repellent film can be raised and lowered to open and close the window. In this application, the water-repellent film preferably has a wear resistance that reduces water repellency even when the surface is repeatedly rubbed.

[0089] Generally, from the viewpoint of reducing the water rolling-off angle, the lower the elastic modulus of the surface of the water-repellent layer, the better, while from the viewpoint of improving the abrasion resistance, the higher the elastic modulus of the surface of the water-repellent layer, the better. If the elastic modulus of the surface of the water-repellent layer is reduced, water will roll off easily, and the dynamic water repellency can be improved, but the abrasion resistance tends to decrease. Therefore, dynamic water repellency and abrasion resistance are essentially contradictory properties.

[0090] In the water-repellent structure disclosed herein, the surface of the water-repellent layer has a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square. With this structure, the surface of the water-repellent layer can have both water roll-off and rigidity as a whole, and can improve wear resistance while having good dynamic water repellency.

[0091] In order to achieve dynamic water repellency and abrasion resistance at the same time, it is believed that it is effective to have the high elastic modulus portion and the low elastic modulus portion exist independently as regions of appropriate size. It is believed that the high elastic modulus portion existing as a region of appropriate size contributes to the improvement of abrasion resistance, and the low elastic modulus portion existing as a region of appropriate size can reduce the water roll-off angle and contribute to the improvement of dynamic water repellency.

[0092] From the viewpoint of the balance between dynamic water repellency and improvement of abrasion resistance, the root mean square slope of the surface elastic modulus in the micrometer region is 3.5 GPa or more, preferably 4.0 GPa or more, more preferably 4.5 GPa or more, particularly preferably 5.0 GPa or more.

[0093] From the viewpoint of the balance between dynamic water repellency and improvement of abrasion resistance, the root mean square slope of the surface elastic modulus in the micrometer region is preferably 35.0 GPa or less, more preferably 30.0 GPa or less, particularly preferably 25.0 GPa or less, and most preferably 20.0 GPa or less.

[0094] When the root mean square slope is within the above range, the high elastic modulus portion and the low elastic modulus portion are each independently present as a region of an appropriate size, and dynamic water repellency and abrasion resistance can be simultaneously achieved in a well-balanced manner.

[0095] For the surface of the water-repellent layer when the root mean square slope is too small, it is believed that the high elastic modulus portion and the low elastic modulus portion exist as regions independently, but the size of these regions is in a state larger than the appropriate size, or there is no clear boundary between the high elastic modulus portion and the low elastic modulus portion, and the high elastic modulus portion and the low elastic modulus portion are not in a state where they exist independently as regions. For the surface of the water-repellent layer when the root mean square slope is too large, it is believed that the high elastic modulus portion and the low elastic modulus portion exist as regions independently, but the size of these regions is in a state smaller than the appropriate size. In such a state, it is believed that it is difficult to achieve dynamic water repellency and abrasion resistance with good balance at the same time.

[0096] From the viewpoint of the balance between dynamic water repellency and improvement of abrasion resistance, the average elastic modulus of the micrometer region on the surface of the water-repellent layer is preferably 2.0 to 14.0 GPa, more preferably 2.4 to 10.0 GPa.

[0097] From the viewpoint of the balance between water repellency and improved abrasion resistance, in the micron region of the surface of the water repellent layer, the area ratio of the high elastic modulus region with an elastic modulus of 6.0 GPa or more is preferably 1 to 50%, more preferably 2 to 40%, and particularly preferably 3 to 30%. The area ratio of the low elastic modulus region with an elastic modulus of 4.0 GPa or less is preferably 10 to 80%, more preferably 20 to 78%, and particularly preferably 40 to 72%.

[0098] The initial water contact angle of the surface of the water-repellent layer is preferably 90° or more, more preferably 95° or more, and particularly preferably 100° or more. The upper limit of the initial water contact angle is not particularly limited, and is, for example, 110°.

[0099] The initial water roll-off angle of the surface of the water-repellent layer is preferably 30° or less, more preferably 26° or less, and particularly preferably 25° or less. The lower limit of the initial water roll-off angle is not particularly limited, and is, for example, 3°.

[0100] In the present specification, "initial" is defined as the period from the moment when the water-repellent film is formed on the substrate to the time when the water-repellent film is left at room temperature (20 to 25°C) for 150 hours without any special treatment or manipulation.

[0101] The “time when the water-repellent film formation is completed” means the time when the coating film formed from the water-repellent layer-forming composition is completely cured.

[0102] The initial water contact angle and the initial water roll-off angle can be measured by the method described in the section [Examples] described later.

[0103] The abrasion resistance of the surface of the water-repellent layer can be evaluated by the water contact angle after performing an abrasion test.

[0104] The abrasion test can be performed, for example, as follows.

[0105] As a testing machine, a reciprocating traverse testing machine manufactured by KNT Corporation was prepared.

[0106] As the dust liquid, a liquid prepared by dispersing eight types of test powders 1 specified in JIS Z8901 in pure water at a concentration of 2.5% by mass was prepared.

[0107] As a wear part, a Toyota Motor Corporation automobile door mold "MOULDING75720-47010" was cut into pieces with an area of ​​4.0 cm 2 Rectangular material.

[0108] On a real vehicle, 20 μL of the dust liquid was infiltrated into the part of the wear component that came into contact with the glass. The wear component was mounted on the testing machine and the surface of the water-repellent layer of the water-repellent structure was abraded 5,000 times back and forth under the conditions of a load of 350 g, a speed of 50 reciprocating / min, and a rubbing distance of 10 cm.

[0109] In the water-repellent layer of the water-repellent structure of the present disclosure, the water contact angle of the surface after the abrasion test may be 80° or more.

[0110] (Base material)

[0111] The substrate is not particularly limited as long as it is a substrate to which water repellency needs to be imparted.

[0112] As the constituent material of the substrate, glass, metal, resin, ceramic and a combination thereof can be exemplified. The water-repellent film included in the water-repellent structure of the present disclosure can be transparent. According to the technology disclosed in the present disclosure, water repellency can be imparted to transparent substrates such as glass and transparent resin while maintaining transparency.

[0113] The form of the substrate may be a planar body such as a plate, a sheet, or a film. The planar body may be flat as a whole or may be curved at least in part.

[0114] In applications such as window glass for transportation equipment, the substrate may include a glass plate. Examples of the glass plate include tempered glass, laminated glass formed by bonding multiple glass plates via an intermediate film, and organic glass. In applications such as window glass for transportation equipment, tempered glass or laminated glass is preferred.

[0115] The type of glass plate used as the material of the tempered glass and the laminated glass is not particularly limited, and examples thereof include soda-lime glass, borosilicate glass, aluminosilicate glass, lithium silicate glass, quartz glass, sapphire glass, and alkali-free glass.

[0116] The tempered glass is obtained by subjecting the above-mentioned glass plate to a tempering process by a known method such as an ion exchange method and an air-cooling tempering method. As the tempered glass, an air-cooling tempered glass is preferred.

[0117] The thickness of the tempered glass is not particularly limited and can be designed according to the application. In applications such as vehicle window glass (front window glass, side window glass, and rear window glass), the thickness is preferably 2 to 6 mm.

[0118] The thickness of the laminated glass is not particularly limited and can be designed according to the application. In applications such as vehicle window glass (front window glass, side window glass, and rear window glass), the thickness is preferably 2 to 6 mm.

[0119] In applications such as vehicle window glass, a glass plate may be processed into a shape having a curved surface.

[0120] The resin may, for example, be an acrylic resin such as polymethyl methacrylate, an aromatic polycarbonate resin such as polyphenylene carbonate, or an aromatic polyester resin such as polyethylene terephthalate (PET).

[0121] The water-repellent film is formed on at least the region on the surface of the substrate that requires water repellency. When the substrate is a planar body such as a plate, a sheet, or a film, the water-repellent film may be formed on at least one surface of the planar body.

[0122] (Water repellent layer)

[0123] The water-repellent film includes a water-repellent layer containing a siloxane bond (Si—O bond) and one or more organic groups bonded to a Si atom but containing no fluorine atom.

[0124] One or more organic groups may be selected from alkyl groups and alkylene groups.

[0125] The surface of the water-repellent layer has an elastic modulus distribution, and has a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square. The root mean square slope of the surface elastic modulus in the micron region is above 3.5 GPa. The root mean square slope of the surface elastic modulus in the micron region is preferably below 35.0 GPa, more preferably below 30.0 GPa.

[0126] The water-repellent layer can be formed, for example, by using a water-repellent layer-forming composition containing one or more hydrolyzable silicon compounds (ST) that are partially hydrolyzable and condensable between the same type or different types.

[0127] The water-repellent layer is preferably formed by using a water-repellent layer-forming composition comprising one or more hydrolyzable silicon compounds (ST) of the same type or different types that can be partially hydrolyzed and condensed and one or more organic solvents (VT).

[0128] The water-repellent layer may be a dried solid product of the water-repellent layer-forming composition.

[0129] The one or more hydrolyzable silicon compounds (ST) are preferably a plurality of hydrolyzable silicon compounds that contain one or more hydrolyzable organic silicon compounds (SC) and one or more hydrolyzable alkylsilanes (SR) and are partially hydrolyzable and condensable with each other of the same type or different types.

[0130] The solubility parameter based on Hansen's definition, that is, the HSP value (hereinafter also referred to as "HSP value") of the one or more organic solvents (VT) is preferably 10.8 to 12.1. When the organic solvent (VT) is a mixed solvent, the HSP value is the HSP value of the mixed solvent.

[0131] The water-repellent layer may include a dried solidified product of a composition of a plurality of hydrolyzable silicon compounds (ST) and one or more organic solvents (VT), wherein the plurality of hydrolyzable silicon compounds (ST) include one or more hydrolyzable organic silicon compounds (SC) and one or more hydrolyzable alkyl silanes (SR), and the same or different types may be partially hydrolyzed and condensed, the amount of the one or more hydrolyzable alkyl silanes (SR) is 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable organic silicon compounds (SC) and the one or more hydrolyzable alkyl silanes (SR), and the one or more organic solvents (VT) have a solubility parameter based on the Hansen definition, i.e., an HSP value of 10.8 to 12.1.

[0132] By using the above composition, it is easy to form a water-repellent layer having the above-mentioned specific elastic modulus distribution.

[0133] <Hydrolyzable Silicone (SC)>

[0134] As the hydrolyzable silicone (SC), a compound represented by the following formula (1) (also referred to as compound (1)) is preferred. One or more types of compound (1) may be used.

[0135] R 13 -(SiR 12 2O) k1 -SiR 12 2-Y 1 -Si(R 11 ) 3-n1 (X 1 ) n1 ……(1)

[0136] (In the above formula, R 13 is an alkyl group having 1 to 30 carbon atoms, R 12 are independently an alkyl group having less than 3 carbon atoms, Y 1 is an alkylene group having 2 to 4 carbon atoms or an oxygen atom, R 11 are independently a monovalent hydrocarbon group, X 1 are independently hydrolyzable groups, X 1 It can be hydrolyzed to form a hydroxyl group, k1 is an integer from 10 to 300, and n1 is an integer from 1 to 3.)

[0137] Compound (1) has an alkyl group (R 13 ), having a hydrolyzable group (X 1 ) of a linear polysiloxane.

[0138] The water-repellent layer obtained by using the compound (1) is considered to be X of the compound (1). 1 Or from X 1 The water-repellent layer obtained by using compound (1) can be excellent in both static water repellency and dynamic water repellency. The water-repellent layer can also be excellent in abrasion resistance.

[0139] In addition, in this specification, "underlying layer of a water-repellent layer" refers to a base material or underlayer located immediately below the water-repellent layer.

[0140] It is considered that on the surface of the water-repellent layer obtained using one or more compounds (1) and one or more hydrolyzable alkylsilanes (SR), a high elastic modulus portion of 6.0 GPa or more is easily formed due to the alkyl and / or alkylene groups derived from the compounds (1) and the hydrolyzable alkylsilane (SR), thereby effectively improving durability such as abrasion resistance.

[0141] From the viewpoint of improving the solubility of the compound (1) in the water-repellent layer-forming composition, the coating properties of the water-repellent layer-forming composition, and the abrasion resistance of the water-repellent layer, R 13 It is an alkyl group having 1 to 30 carbon atoms.

[0142] The alkyl group may, for example, be a linear alkyl group, a branched alkyl group or an alkyl group including a cyclic structure, and a linear alkyl group is preferred.

[0143] As the number of carbon atoms of the alkyl group in the compound (1) increases, the maximum elastic modulus of the surface of the water-repellent layer increases, the abrasion resistance of the water-repellent layer tends to increase, and the dynamic water repellency tends to decrease.

[0144] The lower limit of the number of carbon atoms in the alkyl group is preferably 2, more preferably 3, and particularly preferably 4. The upper limit of the number of carbon atoms in the alkyl group is preferably 20, and more preferably 10.

[0145] Can be combined with R 13 For example, R 13 The compound (1) having 4 or more carbon atoms and R 13 A compound (1) wherein the number of carbon atoms is less than 3.

[0146] R 12 Each of the R groups is independently an alkyl group having 3 or less carbon atoms, preferably a linear alkyl group having 3 or less carbon atoms, and more preferably a methyl group. 12 They may be the same or different, preferably the same.

[0147] Y 1 Y is an alkylene group having 2 to 4 carbon atoms or an oxygen atom. 1 In the case of an alkylene group, the number of carbon atoms is preferably 2-3.

[0148] Y 1 In the case of an alkylene group, compound (1) is preferably Y 1 The compound (1) is a linear alkylene group, and Y 1 A mixture of compounds (1) having a branched alkylene group. 1 In the case of an alkylene group having 2 carbon atoms, the group is represented by -C2H4-, but compound (1) may also be Y 1 The compound (1) is -CH2CH2- and Y1 A mixture of compounds (1) wherein Y 1 Among the compounds (1) where Y is an alkylene group, 1 The proportion of the compound (1) being a linear alkylene group is relatively high.

[0149] R 11 Each of R and R is independently a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, and an aryl group. 11 Preferably, it is a monovalent saturated hydrocarbon group. 11 The number of carbon atoms in R is preferably 1 to 6, more preferably 1 to 3, and particularly preferably 1 to 2. From the viewpoint of the availability of raw materials and the ease of synthesis of compound (1), R 11 An alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1 to 3 carbon atoms is more preferred, and an alkyl group having 1 to 2 carbon atoms is particularly preferred. 11 In the case of multiple R 11 They may be the same or different, but are preferably the same from the viewpoint of easy availability of the raw materials.

[0150] X 1 It is a hydrolyzable group, Si-X 1 Hydrolyze to generate Si-OH. Therefore, in the composition, X 1 It can be hydrolyzed to form a hydroxyl group. Examples of the hydrolyzable group include an alkoxy group, an acyloxy group, a ketoximate group, an alkenyloxy group, an aminooxy group, an amide group, an isocyanate group, and a halogen atom. From the viewpoint of the balance between the chemical stability of the compound (1) and the ease of hydrolysis, an alkoxy group, an isocyanate group, and a halogen atom are preferred. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferred, and a methoxy group and an ethoxy group are more preferred. As the halogen atom, a chlorine atom is preferred. As X 1 , particularly preferably methoxy, ethoxy and chlorine atoms. 1 In the case of multiple X 1 They may be the same or different, but are preferably the same from the viewpoint of easy availability of the raw materials.

[0151] k1 is 10 to 300, preferably 20 to 240, and more preferably 30 to 120. If k1 is within this range, static water repellency and dynamic water repellency can be simultaneously achieved in the water-repellent layer. In addition, compound (1) may be a mixture of a plurality of compounds (1) having different k1. In this case, k1 is represented by an average value.

[0152] n1 is an integer of 1 to 3, and is preferably 2 to 3, and particularly preferably 3, from the viewpoint of improving the adhesion between the water-repellent layer and the substrate.

[0153] Compound (1) can be produced by a known method, for example, by the method described in Patent Document 1. A commercially available product can also be used as Compound (1).

[0154] <Hydrolyzable Alkylsilane (SR)>

[0155] As the hydrolyzable alkylsilane (SR), a compound represented by the following formula (2) (also referred to as compound (2)) is preferred. One or more types of compound (2) may be used.

[0156] R 22 -Si(R 21 ) 3-n2 (X 2 ) n2 ……(2)

[0157] (In the above formula, R 22 is an alkyl group having 1 to 30 carbon atoms, R 21 are independently a monovalent hydrocarbon group, X 2 are independently hydrolyzable groups, X 2 It can be hydrolyzed to form a hydroxyl group, and n2 is an integer from 1 to 3.

[0158] Compound (2) has an alkyl group (R 22 ), having a hydrolyzable group (X 2 ) of alkylsilane.

[0159] The water-repellent layer obtained by using compound (2) is considered to be X of compound (2). 2 Or from X 2 A layer obtained by combining a group with a substrate.

[0160] The water-repellent layer obtained by using one or more hydrolyzable silicones (SC) (preferably one or more compounds (1)) and one or more hydrolyzable alkylsilanes (SR) (preferably one or more compounds (2)) is excellent in both static water repellency and dynamic water repellency and also excellent in abrasion resistance.

[0161] When a relatively large molecular weight hydrolyzable silicone (SC) and a relatively small molecular weight hydrolyzable alkylsilane (SR) are used in combination, it is considered that the relatively small molecular weight hydrolyzable alkylsilane (SR) or its reaction product fills the gaps in the layer, thereby obtaining a dense water-repellent layer having excellent abrasion resistance.

[0162] In addition, on the surface of the water-repellent layer obtained using one or more hydrolyzable alkylsilanes (SR), it is considered that a high elastic modulus portion of 6.0 GPa or more is easily formed due to the alkyl group and / or alkylene group derived from one or more hydrolyzable alkylsilanes (SR), thereby effectively improving durability such as abrasion resistance.

[0163] From the viewpoint of improving the solubility of the compound (2) in the water-repellent layer-forming composition, the coating properties of the water-repellent layer-forming composition, and the abrasion resistance of the water-repellent layer, R 22 It is an alkyl group having 1 to 30 carbon atoms.

[0164] The alkyl group may, for example, be a linear alkyl group, a branched alkyl group or an alkyl group including a cyclic structure, and a linear alkyl group is preferred.

[0165] It is considered that the root mean square slope can be adjusted to a preferred range by forming a high elastic modulus region of an appropriate size by using one or more hydrolyzable alkylsilanes (SR).

[0166] When the carbon chain length of the alkyl group of the hydrolyzable alkylsilane (SR) is too short, it may be difficult to form a high elastic modulus region, and when it is too long, the size of the high elastic modulus region may be too large. If the carbon chain length of the alkyl group of the hydrolyzable alkylsilane (SR) is within an appropriate range, it is easy to form a high elastic modulus region of an appropriate size, and it is easy to adjust the root mean square slope to a preferred range.

[0167] The lower limit of the number of carbon atoms in the alkyl group is preferably 2, more preferably 5, and particularly preferably 8. The upper limit of the number of carbon atoms in the alkyl group is preferably 25, and more preferably 20.

[0168] Can be combined with R 22 For example, R 22 Compounds having 8 or more carbon atoms (2) and R 22 A compound having less than 7 carbon atoms (2).

[0169] R 21 Each of R and R is independently a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, and an aryl group. 21 Preferably, it is a monovalent saturated hydrocarbon group. 21 The number of carbon atoms in R is preferably 1 to 6, more preferably 1 to 3, and particularly preferably 1 to 2. From the viewpoint of the availability of raw materials and the ease of synthesis of compound (2), R 21 An alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1 to 3 carbon atoms is more preferred, and an alkyl group having 1 to 2 carbon atoms is particularly preferred. 21 In the case of multiple R 21 They may be the same or different, but are preferably the same from the viewpoint of easy availability of the raw materials.

[0170] X 2 It is a hydrolyzable group, Si-X 2 Hydrolyze to generate Si-OH. Therefore, in the composition, X 2It can be hydrolyzed to form a hydroxyl group. Examples of the hydrolyzable group include an alkoxy group, an acyloxy group, a ketoximate group, an alkenyloxy group, an amino group, an aminooxy group, an amide group, an isocyanate group, and a halogen atom. From the viewpoint of the balance between the chemical stability of the compound (2) and the ease of hydrolysis, an alkoxy group, an isocyanate group, and a halogen atom are preferred. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferred, and a methoxy group and an ethoxy group are more preferred. As the halogen atom, a chlorine atom is preferred. As X 2 , particularly preferably methoxy, ethoxy and chlorine atoms. 2 In the case of multiple X 2 They may be the same or different, but are preferably the same from the viewpoint of easy availability of the raw materials.

[0171] n2 is an integer of 1 to 3, and is preferably 2 to 3, and particularly preferably 3, from the viewpoint of improving the adhesion between the water-repellent layer and the substrate.

[0172] Preferred compounds (2) include R 22 is a straight-chain alkyl group having 8 to 20 carbon atoms, X 2 The compound wherein n2 is a methoxy group, an ethoxy group or a chlorine atom and n2 is 3. Specifically, octyltrimethoxysilane, octyltrichlorosilane, octadecyltrimethoxysilane and octadecyltrichlorosilane may be mentioned.

[0173] Compound (2) can be produced by a known method, or a commercially available product can be used as Compound (2).

[0174] <Other hydrolyzable silicon compounds>

[0175] The one or more hydrolyzable silicon compounds (ST) may further contain one or more other hydrolyzable silicon compounds other than the hydrolyzable organosilicon (SC) and the hydrolyzable alkylsilane (SR).

[0176] <Mixing ratio>

[0177] In the water-repellent layer-forming composition, the amount of the at least one hydrolyzable silicone (SC) is preferably 99 to 50 parts by mass, and the amount of the at least one hydrolyzable alkyl silane (SR) is preferably 1 to 50 parts by mass, relative to 100 parts by mass of the total amount of the at least one hydrolyzable silicone (SC) and the at least one hydrolyzable alkyl silane (SR).

[0178] By designing the compounding ratio as described above, it is easy to form a water-repellent layer having the above-mentioned specific elastic modulus distribution, having good water repellency in the initial state, and having abrasion resistance with little reduction in water repellency even after repeated friction of the surface.

[0179] More preferably, the amount of the at least one hydrolyzable silicone (SC) is 97 to 75 parts by mass, and the amount of the at least one hydrolyzable alkyl silane (SR) is 3 to 25 parts by mass, relative to 100 parts by mass of the total amount of the at least one hydrolyzable silicone (SC) and the at least one hydrolyzable alkyl silane (SR).

[0180] <Organic solvent (VT)>

[0181] As the organic solvent (VT), an organic solvent capable of dissolving the solid components contained in the water-repellent layer-forming composition can be used. As the organic solvent (VT), alcohols, ethers, ketones, aromatic hydrocarbons, paraffin hydrocarbons, and acetates can be cited. More than one organic solvent (VT) can be used.

[0182] When the raw materials of the constituent components of the water-repellent layer-forming composition contain an organic solvent, the one or more organic solvents (VT) include the organic solvent in the raw materials.

[0183] The solubility parameter based on Hansen's definition, i.e., the HSP value of one or more organic solvents (VT) contained in the water-repellent layer-forming composition is preferably 10.8 to 12.1. The HSP value when the organic solvent (VT) is a mixed solvent is the HSP value of the mixed solvent. By using one or more organic solvents (VT) having an HSP value of 10.8 to 12.1, it is easy to form a water-repellent layer having the above-mentioned specific elastic modulus distribution, good water repellency in the initial state, and abrasion resistance in which the water repellency of the surface is less reduced even after repeated friction.

[0184] The content of the organic solvent (VT) in the water-repellent layer-forming composition (the total amount in the case of multiple types) is not particularly limited, but is preferably 80 to 98% by mass, more preferably 85 to 95% by mass, from the viewpoint of thickness control of the water-repellent layer, uniformity of the water-repellent layer, economy, and operability.

[0185] <Water>

[0186] The water-repellent layer-forming composition may contain water as necessary.

[0187] When the raw material of the constituent components of the water-repellent layer-forming composition contains water, the water includes water in the raw material.

[0188] In the step of forming the water-repellent layer, the hydrolysis-condensation reaction of the one or more hydrolyzable silicon compounds (ST) can proceed by utilizing the moisture in the atmosphere. Therefore, the water-repellent layer-forming composition may not contain water.

[0189] The content of water in the water-repellent layer-forming composition is not particularly limited, and is, for example, 0 to 2% by mass.

[0190] <Catalyst>

[0191] The water-repellent layer-forming composition may contain one or more catalysts as necessary.

[0192] When the raw material of the constituent components of the water-repellent layer-forming composition contains a catalyst, the one or more catalysts include the catalyst in the raw material.

[0193] As the catalyst, an acid catalyst and a base catalyst can be mentioned. As the acid catalyst, hydrochloric acid, nitric acid, acetic acid, sulfuric acid, phosphoric acid, sulfonic acid, methanesulfonic acid and p-toluenesulfonic acid can be mentioned. As the base catalyst, sodium hydroxide, potassium hydroxide and ammonia can be mentioned. As the catalyst, an acid catalyst is preferred. The catalyst can be used in the form of an aqueous solution.

[0194] The content of the catalyst in the water-repellent layer-forming composition is not particularly limited. The content of the one or more catalysts (the total amount in the case of multiple types) is preferably 0.01 to 10% by mass relative to 100% by mass of the content of the one or more hydrolyzable silicon compounds (ST) (the total amount in the case of multiple types).

[0195] When one or more hydrolyzable silicon compounds (ST) contain chlorine atoms as hydrolyzable groups, the reactivity of the compound is high, so from the viewpoint of the storage stability of the water-repellent layer-forming composition, the water-repellent layer-forming composition preferably does not substantially contain water and catalyst. Substantially free means that the content in the water-repellent layer-forming composition is less than 0.3% by mass.

[0196] <Other optional ingredients>

[0197] The water-repellent layer-forming composition may contain one or more other optional components other than the above as necessary. Examples of other optional components include additives such as metal oxide particles, coloring materials such as dyes and pigments, antifouling materials, and various resins.

[0198] <Method for forming water-repellent layer>

[0199] The method for forming the water-repellent layer may include, for example, the following steps:

[0200] A step of preparing a water-repellent layer-forming composition comprising one or more hydrolyzable silicon compounds (ST) of the same type or different types that can be partially hydrolyzed and condensed and one or more organic solvents (VT);

[0201] A step of applying the water-repellent layer-forming composition to at least a portion of the surface of a substrate and drying (partially or completely) as necessary to form an uncured water-repellent layer; and

[0202] A step of curing the uncured water-repellent layer.

[0203] Before applying the water-repellent layer-forming composition, a primer layer or an uncured primer layer may be formed on the surface of the substrate.

[0204] Examples of a method for applying the water-repellent layer-forming composition include hand coating, brush coating, flow coating, spin coating, dip coating, blade coating and spray coating.

[0205] As a method for drying the coating layer formed by the water-repellent layer forming composition, there can be mentioned a method of leaving the substrate formed with the coating layer still in any atmosphere such as air atmosphere and nitrogen atmosphere at normal temperature and pressure. The relative humidity of the atmosphere in the drying step is preferably not high, preferably less than 50%, more preferably less than 40%.

[0206] The curing conditions of the uncured water-repellent layer can be appropriately designed according to the composition and concentration of the water-repellent layer-forming composition.

[0207] The curing of the uncured water-repellent layer can be carried out in any atmosphere such as air atmosphere and nitrogen atmosphere at normal pressure. The temperature of the atmosphere is not particularly limited, but is preferably 20 to 80° C. The relative humidity of the atmosphere is not particularly limited, but is preferably 0 to 90%, more preferably 50 to 90%. If the relative humidity of the atmosphere is above 50%, the moisture in the atmosphere can be used to effectively cure the layer.

[0208] The time required for curing varies depending on the composition, concentration, curing conditions, etc. of the water-repellent layer-forming composition, but is preferably about 10 minutes to 72 hours.

[0209] The thickness of the water-repellent layer is not particularly limited as long as it can impart good water repellency and good abrasion resistance to the water-repellent film, but is preferably 50 nm or less from the viewpoint of economic efficiency. The lower limit is the thickness of a monomolecular layer.

[0210] (basal layer)

[0211] The water-repellent film may have a base layer containing siloxane bonds but no fluorine atoms under the water-repellent layer. The base layer can improve the moisture resistance and adhesion of the water-repellent film. The base layer can also function as a barrier layer to prevent components such as alkali from migrating from the substrate to the water-repellent film.

[0212] The base layer can be formed, for example, using a base layer forming composition comprising one or more hydrolyzable silicon compounds (SU) selected from a compound represented by the following formula (3) (also referred to as compound (3)) and a compound represented by the following formula (4) (also referred to as compound (4)), and which are partially hydrolyzable and condensable between the same type or different types.

[0213] Si(X 3 )4……(3)

[0214] (In the above formula, X 3 are independently hydrolyzable groups, X3 Can be hydrolyzed to form hydroxyl groups.)

[0215] X 4 3Si-(CH2) m -SiX 4 3……(4)

[0216] (In the above formula, X 4 are independently hydrolyzable groups, X 4 It can be hydrolyzed to form a hydroxyl group, and m is an integer of 1 to 8.

[0217] The base layer may be a dried solid product of the above-mentioned base layer-forming composition.

[0218] X in formula (3) 3 It is a hydrolyzable group, Si-X 3 Hydrolyze to generate Si-OH. Therefore, in the composition, X 3 It can be hydrolyzed to form a hydroxyl group. Examples of the hydrolyzable group include an alkoxy group, an acyloxy group, a ketoximate group, an alkenyloxy group, an amino group, an aminooxy group, an amide group, an isocyanate group, and a halogen atom. From the viewpoint of the balance between the chemical stability of the compound (3) and the ease of hydrolysis, an alkoxy group, an isocyanate group, and a halogen atom are preferred. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferred, and a methoxy group and an ethoxy group are more preferred. As the halogen atom, a chlorine atom is preferred. As X 3 , particularly preferably methoxy, ethoxy and chlorine atoms. 3 They may be the same or different, but are preferably the same from the viewpoint of easy availability of raw materials. 4 Same here.

[0219] In formula (4), m is an integer of 1 to 8, preferably an integer of 1 to 3. When m is within this range, the base layer has moderate hydrophobicity, the moisture resistance of the water-repellent film can be improved, and the dynamic water repellency of the obtained water-repellent film is good.

[0220] Preferred compounds (3) include Si(NCO)4, Si(OCH3)4 and Si(OC2H5)4.

[0221] Preferred compounds (4) include (CH3O)3SiCH2CH2Si(OCH3)3, (C2H5O)3SiCH2CH2Si(OC2H5)3, (OCN)3SiCH2CH2Si(NCO)3, Cl3SiCH2CH2SiCl3 and (CH3O)3SiCH2CH2CH2CH2CH2CH2Si(OCH3)3.

[0222] <Organic solvents>

[0223] The base layer forming composition may contain one or more organic solvents (VU). Examples of the organic solvents (VU) are the same as those of the water-repellent layer forming composition. The HSP value of the one or more organic solvents (VU) contained in the base layer forming composition is not particularly limited.

[0224] When the raw materials of the constituent components of the base layer forming composition contain an organic solvent, the one or more organic solvents (VU) include the organic solvent in the raw materials.

[0225] The content of the organic solvent (VU) in the base layer forming composition is not particularly limited, but is preferably 80 to 99% by mass, more preferably 90 to 98% by mass, from the viewpoints of base layer thickness control, base layer uniformity, economy, and handling properties.

[0226] <Water>

[0227] The base layer forming composition may contain water as necessary.

[0228] When the raw material of the constituent components of the base layer forming composition contains water, the water includes water in the raw material.

[0229] In the step of forming the base layer, the hydrolysis-condensation reaction of one or more hydrolyzable silicon compounds (SU) can proceed by utilizing the moisture in the atmosphere, and therefore the base layer forming composition may not contain water.

[0230] The content of water in the base layer forming composition is not particularly limited, and is, for example, 0 to 10% by mass.

[0231] <Catalyst>

[0232] The base layer forming composition may contain one or more catalysts as necessary. Examples of the catalyst are the same as those of the catalyst for the water-repellent layer forming composition.

[0233] When the raw material of the constituent components of the underlayer forming composition contains a catalyst, the one or more catalysts include the catalyst in the raw material.

[0234] The content of the catalyst in the base layer forming composition is not particularly limited. The content of the one or more catalysts (the total amount in the case of multiple types) is preferably 0.01 to 10% by mass relative to 100% by mass of the content of the one or more hydrolyzable silicon compounds (SU) (the total amount in the case of multiple types).

[0235] When one or more hydrolyzable silicon compounds (SU) contain chlorine atoms as hydrolyzable groups, the reactivity of the compound is high, so from the viewpoint of the storage stability of the composition for forming a base layer, the composition for forming a base layer preferably does not substantially contain water and catalyst. Substantially free means that the content in the composition for forming a base layer is 0.3% by mass or less.

[0236] <Other optional ingredients>

[0237] The base layer forming composition may contain one or more other optional components other than the above as necessary. Examples of other optional components include additives such as metal oxide particles, coloring materials such as dyes and pigments, antifouling materials, and various resins.

[0238] <Method for forming base layer>

[0239] The method for forming the base layer may include the following steps:

[0240] A step of preparing a base layer forming composition comprising one or more hydrolyzable silicon compounds (SU) of the same type or different types that can be partially hydrolyzed and condensed;

[0241] A step of applying the base layer forming composition to at least a portion of the surface of a substrate and drying (partially or completely) as necessary to form an uncured base layer; and

[0242] The process of curing the uncured base layer.

[0243] The curing of the uncured underlayer may be performed before applying the water-repellent layer-forming composition, or may be performed simultaneously with the curing of the uncured water-repellent layer.

[0244] The method for applying the base layer forming composition and the method for drying the coating layer formed from the base layer forming composition are the same as those for the water-repellent layer forming composition.

[0245] The curing conditions of the uncured base layer can be appropriately designed according to the composition and concentration of the base layer forming composition.

[0246] The curing of the uncured base layer can be carried out in any atmosphere such as air atmosphere and nitrogen atmosphere at normal pressure. The temperature of the atmosphere is not particularly limited, but is preferably 20 to 50° C. The relative humidity of the atmosphere is not particularly limited, but is preferably 50 to 90%. If the relative humidity of the atmosphere is above 50%, the moisture in the atmosphere can be used to effectively cure the base layer.

[0247] The time required for curing varies depending on the composition, concentration, curing conditions, etc. of the base layer forming composition, but is preferably about 1 to 72 hours.

[0248] The thickness of the base layer is not particularly limited as long as it can improve the moisture resistance and adhesion of the water-repellent film and function as a barrier layer, but is preferably 50 nm or less from the viewpoint of economic efficiency. The lower limit is the thickness of a monomolecular layer.

[0249] The surface of the water-repellent layer included in the water-repellent structure of the present disclosure can have good water repellency and be excellent in both static water repellency and dynamic water repellency.

[0250] The water-repellent layer included in the water-repellent structure of the present invention has little water droplets attached to the surface, and even if water droplets are attached, the water droplets are easy to fall naturally. When the water-repellent structure of the present invention is used as an article for transportation equipment, even if water droplets are attached to the surface of the water-repellent layer, the attached water droplets are easy to fall due to wind force when the transportation equipment is running.

[0251] The water-repellent layer included in the water-repellent structure of the present disclosure can have good water repellency in the initial state and has durability to maintain good water repellency even after long-term use. One example of durability is abrasion resistance.

[0252] The water-repellent layer included in the water-repellent structure of the present disclosure has a specific elastic modulus distribution, and can have abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed.

[0253] Since the water-repellent layer included in the water-repellent structure of the present disclosure does not contain fluorine atoms, there is no concern about the influence on the environment.

[0254] As described above, according to the present disclosure, it is possible to provide a water-repellent structure having a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed.

[0255] According to the present disclosure, a water-repellent layer-forming composition capable of forming a non-fluorine-based water-repellent layer having good water repellency in an initial state and having abrasion resistance with little reduction in water repellency even when the surface is repeatedly rubbed can be provided.

[0256] [use]

[0257] The water-repellent structure disclosed herein is suitable for use in articles for transportation equipment, etc. Examples of transportation equipment include electric cars, cars, ships, and airplanes, etc. Examples of articles include vehicle bodies, window glass (front window glass, side window glass, and rear window glass, etc.), rearview mirrors, and bumpers, etc.

[0258] The water-repellent structure of the present disclosure is suitable for use in window glass for transportation equipment, etc. When the water-repellent structure of the present disclosure is used in window glass for transportation equipment, adhesion of rain, frost, ice, snow, etc. can be effectively suppressed, the work of removing them can be reduced, and a good field of vision can be easily ensured.

[0259] Example

[0260] The present invention is described below based on examples, but the present invention is not limited thereto. Examples 1 to 6, 11 to 14, 21 to 23, and 31 are examples, and Examples 51, 52, 61, 62, 71, and 72 are comparative examples. Unless otherwise specified, the normal temperature is 20 to 25°C.

[0261] [Material]

[0262] The following materials were prepared.

[0263] <Compound (1)>

[0264] (Hydrolyzable silicone (1-1))

[0265] Into a reactor (internal volume 50 mL) equipped with a stirrer and a Dimrod cooling tube, the compound (1-m) (10.0 g) represented by the following formula, vinyltrimethoxysilane (1.47 g) and a Pt catalyst (a 2% by mass xylene solution of a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of Pt) (0.015 g) were added and stirred at room temperature for 24 hours.

[0266] [Chemical formula 1]

[0267]

[0268] The volatile components were removed from the obtained reaction crude liquid under the conditions of a temperature of 50° C. and a pressure of 1.3 kPa to obtain 10.4 g of a hydrolyzable silicone (1-1) represented by the following formula. The yield was 98%.

[0269] [Chemical formula 2]

[0270]

[0271] In the above formula, Y 1 For ethylene.

[0272] <Compound (2)>

[0273] C18(OMe): n-octadecyltrimethoxysilane (compound represented by the following formula).

[0274] [Chemical formula 3]

[0275]

[0276] C2(OMe): ethyltrimethoxysilane,

[0277] C6(OMe): n-hexyltrimethoxysilane,

[0278] C8(OMe): n-octyltrimethoxysilane,

[0279] C12(OMe): n-dodecyltrimethoxysilane.

[0280] <Compound (3)>

[0281] (TEOS) tetraethoxysilane (compound represented by the following formula).

[0282] Si(OEt)4

[0283] <Compound (4)>

[0284] (BTE) 1,2-bis(trimethoxysilyl)ethane (compound represented by the following formula).

[0285] [Chemical formula 4]

[0286]

[0287] <Organic solvent (VT)>

[0288] (MeOH) methanol,

[0289] (EtOH) ethanol,

[0290] (i-PrOH) isopropanol,

[0291] (i-BuOH)isobutanol,

[0292] (n-PenOH) n-pentanol,

[0293] (n-HexOH) n-hexanol,

[0294] (n-HepOH) n-heptanol,

[0295] (AcOBu) butyl acetate.

[0296] [Evaluation items and evaluation methods]

[0297] The surface of the water-repellent layer of the water-repellent structure obtained in each example was evaluated as follows. Before the AFM measurement, the surface of the water-repellent layer was wiped several times with a cotton swab soaked in isopropyl alcohol, and the isopropyl alcohol was immediately blown away to remove the surface dirt. Before each other measurement, the surface dirt of the water-repellent layer was removed with a wipe paper containing ethanol or butyl acetate.

[0298] (Elastic modulus distribution, area ratio of a high elastic modulus region with an elastic modulus of 6.0 GPa or more, area ratio of a low elastic modulus region with an elastic modulus of 4.0 GPa or less, root mean square slope of the surface elastic modulus, and average elastic modulus)

[0299] In the measurement of elastic modulus distribution (elastic modulus mapping), an atomic force microscope (AFM, "Cypher S" manufactured by Oxford Instruments) equipped with photothermal excitation technology that realizes stable probe vibration and one of its accessories, AM-FM viscoelastic imaging mode, are used. As a probe, a single crystal diamond probe ("AD-40" manufactured by Adama Innovation) with a small change in contact state caused by wear is used. As a substrate used for calculating the optical lever sensitivity (InvOLS), a sapphire substrate whose substrate surface height is adjusted to be equal to the height of the evaluation sample surface is used. A polystyrene standard sample (elastic modulus of 2.7 GPa) is used as an elastic modulus standard, and the tip shape parameters are adjusted. The new probe is used for elastic modulus distribution measurement after performing surface shape measurement on a 10μm square smooth glass surface for about 20 times at 1Hz. The sample surface height of the evaluation sample is within 1mm and is as close to the same height as possible.

[0300] Obtain the AFM image of the micron area of ​​1 μm square of arbitrary selection on the surface of the water-repellent layer of the water-repellent structure.The elastic modulus distribution is shown with the depth of color on the AFM image obtained.The part with high elastic modulus is shown in white, and the part with low elastic modulus is shown in dark color.The elastic modulus image obtained is analyzed to obtain the area ratio of the high elastic modulus region above 6.0GPa, the area ratio of the low elastic modulus region below 4.0GPa, the root mean square slope of the surface elastic modulus, and the average elastic modulus.

[0301] (Initial water contact angle)

[0302] A water droplet with a diameter of 1 mm was placed on the surface of the water-repellent layer of the water-repellent structure, and the water contact angle was measured using a fully automatic contact angle meter ("M-701" manufactured by Kyowa Interface Science Co., Ltd.) The water contact angle was measured at 6 different locations on the surface of the water-repellent layer, and the average value was used as data.

[0303] (Initial water rolling angle)

[0304] 50 μL of water droplets were dripped on the surface of the water-repellent layer of the water-repellent structure that was kept horizontal relative to the ground, and the inclination angle of the water-repellent structure relative to the horizontal plane was increased by 4 ° per minute. The inclination angle (rolling angle) of the water-repellent structure relative to the horizontal plane when the water droplets began to roll off was measured using a rolling angle measurement system ("SA-11" made by Kyowa Interface Science Society). The measurement was performed at 3 different positions on the surface of the water-repellent layer, and the average value was used as the data. The smaller the rolling angle, the better the dynamic water repellency (water sliding property).

[0305] (Water contact angle after abrasion test)

[0306] As a testing machine, a reciprocating traverse testing machine manufactured by KNT Corporation was prepared.

[0307] As the dust liquid, a liquid prepared by dispersing eight types of test powders 1 specified in JIS Z8901 in pure water at a concentration of 2.5% by mass was prepared.

[0308] As the wear part, a mold for automobile door "MOULDING75720-47010" manufactured by Toyota Motor Corporation was cut into pieces with an area of ​​4.8 cm 2 Rectangular material.

[0309] On the actual vehicle, 20 μL of dust liquid was infiltrated into the part of the wear part that was in contact with the glass. The wear part was mounted on the testing machine. Under the conditions of a load of 3N, a speed of 50 reciprocating / min, and a rubbing distance of 10cm, the surface of the water-repellent layer of the water-repellent structure was abraded 5000 times by the wear part. The water contact angle of the surface of the water-repellent layer after the abrasion test was obtained by the same method as (initial water contact angle).

[0310] [Example 1]

[0311] (Preparation of base layer forming composition (U1))

[0312] 8.7 g of isopropyl alcohol (i-PrOH) was added to a glass container, and 0.23 g of tetraethoxysilane (TEOS) and 0.22 g of 1,2-bis(triethoxysilyl)ethane (BTE) were added. Then, 0.84 g of a 0.463 mass % nitric acid aqueous solution was added dropwise, and the mixture was mixed and stirred at room temperature for about 3 hours to prepare a composition for forming a base layer (U1).

[0313] (Preparation of water-repellent layer-forming composition (T1))

[0314] 7.2 g of isobutyl alcohol (i-BuOH) was added to a glass container, and 1.7 g of isopropyl alcohol (i-PrOH) and 0.99 g of hydrolyzable organosilicon (1-1) were added, and the mixture was mixed and stirred at room temperature for about 1 minute. Next, 0.17 g of a 10% by mass aqueous solution of nitric acid was added by dropwise addition, and the mixture was mixed and stirred at 60° C. for 2 hours using a water bath. Then, 0.010 g of octadecyltrimethoxysilane (C18OMe) as an alkylsilane was added, and the mixture was mixed and stirred at 60° C. for 1 hour to prepare a composition (T1) for forming a water-repellent layer.

[0315] In the water-repellent layer-forming composition (T1), the amount of the hydrolyzable silicone is 99.0% by mass, and the amount of the alkylsilane is 1.0% by mass, relative to the total amount of the hydrolyzable silicone and the alkylsilane of 100% by mass. The solvent used is a mixed solvent of i-BuOH / i-PrOH (mass ratio 8 / 2), and the HSP value of the mixed solvent is 11.6. The solid content concentration of the water-repellent layer-forming composition (T1) is 10% by mass.

[0316] (Manufacture of water-repellent structure)

[0317] As a substrate, high heat ray absorbing glass ("UVFL" manufactured by AGC Corporation, 300 mm×300 mm, 3.5 mm thick) was prepared.

[0318] 0.50 g of the underlayer-forming composition (U1) was applied on one surface of the substrate by a doctor blade method and dried at room temperature for about 1 minute to form an uncured underlayer.

[0319] Next, 0.50 g of the water-repellent layer-forming composition (T1) was applied onto the surface of the uncured underlayer by a doctor blade coating method.

[0320] Then, the obtained laminate was placed in a constant temperature and humidity chamber set at 50°C and a relative humidity of 60% for about 15 minutes. The laminate was taken out from the constant temperature and humidity chamber, and the surface of the laminate was wiped with a wiping paper ("KimWipe" manufactured by Kimberly-Clark Corporation) impregnated with 1.0 mL of butyl acetate to remove excess water-repellent layer-forming composition. The laminate was placed in a constant temperature and humidity chamber set at 50°C and a relative humidity of 60% for about 47 hours.

[0321] As described above, a water-repellent structure in which a water-repellent film composed of a base layer and a water-repellent layer was formed on one surface of a glass plate was obtained.

[0322] Main production conditions and evaluation results are shown in Table 1. In the examples shown in Table 1, conditions not described in the table are common conditions.

[0323] [Examples 2~6, 11~14, 21~23, 51, 52, 61, 62, 71, 72]

[0324] In each of Examples 2 to 6, 11 to 14, 21 to 23, 51, 52, 61, 62, 71, and 72, except for changing one or more of the conditions among the type of hydrolyzable silicone, the type of alkylsilane, the mass ratio of hydrolyzable silicone to alkylsilane, and the type of solvent used, the same operation as the preparation of the water-repellent layer forming composition of Example 1 was carried out to obtain water-repellent layer forming compositions (T2) to (T6), (T11) to (T14), (T21) to (T23), (T51), (T52), (T61), (T62), (T71), and (T72).

[0325] In each of Examples 2 to 6, 11 to 14, 21 to 23, 51, 52, 61, 71, and 72, a water-repellent structure was obtained in the same manner as in Example 1 except that the obtained water-repellent layer-forming composition was used instead of the water-repellent layer-forming composition (T1).

[0326] The water-repellent layer-forming composition (T62) obtained in Example 62 had poor compatibility of materials, and phase separation occurred, resulting in failure to form a film.

[0327] Main production conditions and evaluation results are shown in Tables 1 to 6.

[0328] [Example 31]

[0329] A water-repellent structure was obtained in the same manner as in Example 3 except that the application and drying of the base layer forming composition (U1) were not performed.

[0330] Table 3 shows the main manufacturing conditions and evaluation results.

[0331] [Table 1]

[0332]

[0333] [Table 2]

[0334]

[0335] [Table 3]

[0336]

[0337] [Table 4]

[0338]

[0339] [Table 5]

[0340]

[0341] [Table 6]

[0342]

[0343] [Results Summary]

[0344] In Examples 1 to 6, 11 to 14, and 21 to 23, a composition for forming a base layer was prepared, which contained one or more hydrolyzable silicon compounds selected from compound (3) and compound (4) and which were partially hydrolyzable and condensable between the same type or different types. In these examples, a composition for forming a water-repellent layer was also prepared, which contained a plurality of hydrolyzable silicon compounds and one or more organic solvents, wherein the plurality of hydrolyzable silicon compounds contained one or more hydrolyzable organic silicon compounds having a hydrolyzable group and one or more hydrolyzable alkyl silanes having a hydrolyzable group and an alkyl group, and which were partially hydrolyzable and condensable between the same type or different types, and the amount of the one or more hydrolyzable alkyl silanes was 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable organic silicon compounds and the one or more hydrolyzable alkyl silanes, and the HSP value of the one or more organic solvents was 10.8 to 12.1. In these examples, a water-repellent film consisting of a laminated structure of a base layer and a water-repellent layer was formed using the above-mentioned composition for forming a base layer and the above-mentioned composition for forming a water-repellent layer.

[0345] In Example 31, a water-repellent layer-forming composition comprising a plurality of hydrolyzable silicon compounds and one or more organic solvents was prepared, wherein the plurality of hydrolyzable silicon compounds comprised one or more hydrolyzable organic silicon compounds having a hydrolyzable group and one or more hydrolyzable alkyl silanes having a hydrolyzable group and an alkyl group, and the same type or different types can be partially hydrolyzed and condensed, the amount of the one or more hydrolyzable alkyl silanes was 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable organic silicon compounds and the one or more hydrolyzable alkyl silanes, and the HSP value of the one or more organic solvents was 10.8 to 12.1. In this example, a water-repellent film consisting of a single-layer structure of a water-repellent layer was formed using the water-repellent layer-forming composition.

[0346] The surface of the water-repellent layer obtained in Examples 1 to 6, 11 to 14, 21 to 23, and 31 has an elastic modulus distribution, with a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region is 3.5 to 35.0 GPa. The surface of the water-repellent layer obtained in these examples has an initial water contact angle of 90° or more, an initial water roll-off angle of 30° or less, and a water contact angle of 80° or more on the surface after the abrasion test.

[0347] As a representative example, the elastic modulus image of the micrometer region of the water-repellent layer obtained in Example 3 is shown in FIG. Figure 3 .

[0348] In these examples, the AFM observation area was changed, and the elastic modulus distribution of a total of 10 micrometer areas was evaluated. In any of the 10 AFM observation images of 1 μm square randomly selected at any of these examples, all AFM observation images met the above regulations. In addition, the elastic modulus data recorded in the table are the data of the AFM observation image observed first in each example.

[0349] In Example 51, except that alkylsilane was not used, the same operation as in Examples 1 to 6 was performed to form a water-repellent film consisting of a laminated structure of a base layer and a water-repellent layer. The surface of the water-repellent layer obtained in this example did not have a high elastic modulus portion with an elastic modulus of more than 6.0 GPa in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region was less than 3.5 GPa. The water contact angle of the surface of the water-repellent layer obtained in this example was significantly reduced after the abrasion test, and the abrasion resistance was poor.

[0350] In Example 52, a water-repellent film having a laminated structure of a base layer and a water-repellent layer was formed using the same materials as in Examples 1 to 6. In this example, the amount of the one or more hydrolyzable alkyl silanes was greater than 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable silicones and the one or more hydrolyzable alkyl silanes.

[0351] The surface of the water-repellent layer obtained in this example has an elastic modulus distribution, with a high elastic modulus portion with an elastic modulus of more than 6.0 GPa and a low elastic modulus portion with an elastic modulus of less than 4.0 GPa in an arbitrarily selected micron region of 1 μm square. However, the root mean square slope of the surface elastic modulus in the micron region is less than 3.5 GPa. The initial water roll-off angle of the surface of the water-repellent layer obtained in this example is greater than 30°.

[0352] In Example 61, a water-repellent film having a laminated structure of a base layer and a water-repellent layer was formed in the same manner as in Example 3 except that the type of the mixed solvent was changed. The HSP value of the mixed solvent used was less than 10.8.

[0353] The root mean square slope of the surface elastic modulus of the micrometer region of the surface of the water-repellent layer obtained in this example was less than 3.5 GPa. The water contact angle of the surface of the water-repellent layer obtained in this example after the abrasion test was significantly reduced, and the abrasion resistance was poor.

[0354] The elastic modulus image of the micrometer region of the water-repellent layer obtained in Example 61 is shown in Figure 4 .

[0355] In Example 62, a water-repellent film having a laminated structure of a base layer and a water-repellent layer was formed in the same manner as in Example 3 except that the type of the mixed solvent was changed. The HSP value of the mixed solvent used was greater than 12.1.

[0356] In this example, the compatibility of the materials of the water-repellent layer-forming composition was poor, and the water-repellent layer could not be formed.

[0357] In Examples 71 and 72, a water-repellent film having a laminated structure of a base layer and a water-repellent layer was formed in the same manner as in Example 3 except that the type of alkylsilane was changed.

[0358] The surface of the water-repellent layer obtained in these examples has no high elastic modulus portion with an elastic modulus of 6.0 GPa or more in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus in the micron region is less than 3.5 GPa. The water contact angle of the surface of the water-repellent layer obtained in these examples after the abrasion test is significantly reduced, and the abrasion resistance is poor.

[0359] The present invention is not limited to the above-described embodiments and examples, and design changes may be appropriately made without departing from the gist of the present invention.

[0360] This application claims priority based on Japanese patent application No. 2022-118374 filed on July 26, 2022, the disclosure of which is incorporated herein in its entirety.

[0361] Explanation of symbols

[0362] 1, 2: water-repellent structure, 10: substrate, 20, 30: water-repellent film, 21, 31: water-repellent layer, 32: base layer.

Claims

1. A water-repellent structure comprising a substrate and a water-repellent film formed on a surface of the substrate, wherein: The water-repellent film comprises a water-repellent layer containing a siloxane bond and one or more organic groups bonded to Si atoms but containing no fluorine atoms. The surface of the water-repellent layer is the outermost surface of the water-repellent film, The surface of the water-repellent layer has an elastic modulus distribution, including a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region is above 3.5 GPa.

2. The water-repellent structure according to claim 1, wherein: The root mean square slope of the surface elastic modulus of the micrometer region is below 35.0 GPa.

3. The water-repellent structure according to claim 1 or 2, wherein: The one or more organic groups are selected from alkyl groups and alkylene groups.

4. The water-repellent structure according to claim 1 or 2, wherein: The average elastic modulus of the micron region on the surface of the water-repellent layer is 2.0 to 14.0 GPa.

5. The water-repellent structure according to claim 1 or 2, wherein: In the micron region on the surface of the water-repellent layer, the area ratio of the high elastic modulus region with an elastic modulus of 6.0 GPa or more is 1 to 50%, and the area ratio of the low elastic modulus region with an elastic modulus of 4.0 GPa or less is 10 to 80%.

6. The water-repellent structure according to claim 1 or 2, wherein: The initial water contact angle of the surface of the water-repellent layer is greater than 90°.

7. The water-repellent structure according to claim 1 or 2, wherein: The water-repellent layer is a dried solidified product of a composition comprising a plurality of hydrolyzable silicon compounds and one or more organic solvents, wherein the plurality of hydrolyzable silicon compounds include one or more hydrolyzable silicones having a hydrolyzable group and one or more hydrolyzable alkyl silanes having a hydrolyzable group and an alkyl group, and the same type or different types can be partially hydrolyzed and condensed, the amount of the one or more hydrolyzable alkyl silanes is 1 to 50 parts by mass relative to 100 parts by mass of the total amount of the one or more hydrolyzable silicones and the one or more hydrolyzable alkyl silanes, and the one or more organic solvents have a solubility parameter based on Hansen's definition, i.e., an HSP value of 10.8 to 12.

1.

8. The water-repellent structure according to claim 7, wherein: The hydrolyzable silicone is a compound represented by the following formula (1), and the hydrolyzable alkylsilane is a compound represented by the following formula (2): R 13 -(SiR 12 2O) k1 -SiR 12 2-Y 1 -Si(R 11 ) 3-n1 (X 1 ) n1 ……(1) In the above formula (1), R 13 is an alkyl group having 1 to 30 carbon atoms, R 12 are independently an alkyl group having less than 3 carbon atoms, Y 1 is an alkylene group having 2 to 4 carbon atoms or an oxygen atom, R 11 are independently a monovalent hydrocarbon group, X 1 are independently hydrolyzable groups, X 1 It can be hydrolyzed to form a hydroxyl group, k1 is an integer from 10 to 300, and n1 is an integer from 1 to 3. R 22 -Si(R 21 ) 3-n2 (X 2 ) n2 ……(2) In the above formula (2), R 22 is an alkyl group having 1 to 30 carbon atoms, R 21 are independently a monovalent hydrocarbon group, X 2 are independently hydrolyzable groups, X 2 It can be hydrolyzed to form a hydroxyl group, and n2 is an integer of 1 to 3.

9. The water-repellent structure according to claim 1 or 2, wherein: The water-repellent film has a base layer containing siloxane bonds but no fluorine atoms under the water-repellent layer.

10. The water-repellent structure according to claim 9, wherein: The base layer is a dried solidified product of a composition comprising one or more hydrolyzable silicon compounds selected from the group consisting of a compound represented by the following formula (3) and a compound represented by the following formula (4), and the compounds are the same type or different types and can be partially hydrolyzed and condensed. Si(X 3 )4……(3) In the above formula (3), X 3 are independently hydrolyzable groups, X 3 Can be hydrolyzed to form hydroxyl groups. X 4 3Si-(CH2) m -SiX 4 3……(4) In the above formula (4), X 4 are independently hydrolyzable groups, X 4 It can be hydrolyzed to form a hydroxyl group, and m is an integer of 1-8.

11. The water-repellent structure according to claim 1 or 2, wherein: The substrate includes a glass plate.

12. A composition for forming a water-repellent layer, comprising a plurality of hydrolyzable silicon compounds and one or more organic solvents, wherein the plurality of hydrolyzable silicon compounds comprises one or more hydrolyzable organic silicon compounds having a hydrolyzable group and one or more hydrolyzable alkyl silanes having a hydrolyzable group and an alkyl group, and the same or different types of hydrolyzable silicon compounds can be partially hydrolyzed and condensed. The amount of the one or more hydrolyzable alkylsilanes is 1 to 50 parts by mass based on 100 parts by mass of the total amount of the one or more hydrolyzable silicones and the one or more hydrolyzable alkylsilanes. The at least one organic solvent has a solubility parameter (HSP) value based on Hansen's definition of 10.8 to 12.

1.

13. The composition for forming a water-repellent layer according to claim 12, wherein The hydrolyzable silicone is a compound represented by the following formula (1), and the hydrolyzable alkylsilane is a compound represented by the following formula (2): R 13 -(SiR 12 2O) k1 -SiR 12 2-Y 1 -Si(R 11 ) 3-n1 (X 1 ) n1 ……(1) In the above formula (1), R 13 is an alkyl group having 1 to 30 carbon atoms, R 12 are independently an alkyl group having less than 3 carbon atoms, Y 1 is an alkylene group having 2 to 4 carbon atoms or an oxygen atom, R 11 are independently a monovalent hydrocarbon group, X 1 are independently hydrolyzable groups, X 1 It can be hydrolyzed to form a hydroxyl group, k1 is an integer from 10 to 300, and n1 is an integer from 1 to 3. R 22 -Si(R 21 ) 3-n2 (X 2 ) n2 ……(2) In the above formula (2), R 22 is an alkyl group having 1 to 30 carbon atoms, R 21 are independently a monovalent hydrocarbon group, X 2 are independently hydrolyzable groups, X 2 It can be hydrolyzed to form a hydroxyl group, and n2 is an integer of 1 to 3.

14. A composition for forming a water-repellent layer as described in claim 12 or 13, which is used to form a water-repellent layer, wherein the surface of the water-repellent layer has an elastic modulus distribution, and has a high elastic modulus portion with an elastic modulus of 6.0 GPa or more and a low elastic modulus portion with an elastic modulus of 4.0 GPa or less in an arbitrarily selected micron region of 1 μm square, and the root mean square slope of the surface elastic modulus of the micron region is above 3.5 GPa.

Images