JP7809259B2 - Faucet - Google Patents

Description

The present invention relates to a faucet with a water-repellent layer on its surface, and more specifically to a faucet in which the water-repellent layer is applied to a portion that will be in contact with water for an extended period of time.

Domestic water, including tap water, contains silicon and calcium, which are the causes of limescale. For wet area components that come into contact with domestic water, there is a need to prevent limescale buildup or to make it easy to remove any limescale that does buildup. To prevent limescale and other contaminants from adhering to the surface of wet area components or to improve the removability of such contaminants, there are known techniques for modifying the surface of the components, such as by coating them with a protective layer.

However, it has been observed that the application of a protective layer can result in discoloration, and damage or peeling of the protective layer can mar the appearance of the component. Meanwhile, since it is difficult to prevent dirt from adhering to the surface of wet-area components, the dirt is removed by cleaning. When cleaning hard-to-remove dirt such as limescale, methods such as polishing with special detergents are used, which is a burdensome task to perform on a daily basis. Therefore, there is a demand for a method that can remove dirt with simple cleaning.

Anti-fouling technology using a monomolecular film that is directly chemically bonded to the substrate as a protective layer is known. For example, Japanese Patent Application Laid-Open No. 2004-217950 (Patent Document 1) describes how coating the surface of a faucet with a fluoroalkylphosphonic acid can facilitate the removal of limescale. The monomolecular film is an invisible thin layer, and its application is unlikely to impair the appearance of the component while still providing the functionality of a monomolecular film. Furthermore, by forming a dense monomolecular film using phosphonic acid, the majority of the hydroxyl groups on the substrate surface are shielded, preventing the adhesion of dirt to the substrate surface and making it easy to remove. For example, Japanese Patent Application Laid-Open No. 2000-265526 (Patent Document 2) describes how applying an anti-fouling layer that shields hydroxyl groups on the surface of ceramics can inhibit the adhesion of silica scale dirt. This stain-resistant layer is disclosed as being made by coating and drying a mixture of hydroxyl groups on the ceramic surface, an organosilicon compound containing a fluoroalkyl group, a methylpolysiloxane compound containing a hydrolyzable group, and an organopolysiloxane compound.

Regarding the surface properties of sanitary equipment components, Japanese Patent Application Laid-Open No. 2018-165394 (Patent Document 3) describes how smoothing the stainless steel surface (arithmetic mean roughness Ra of 0.05 μm or less, maximum valley depth Pv of 2.0 μm or less) improves the ease of wiping off oil stains, and US Patent Application Laid-Open No. 2015/0239023 (Patent Document 4) describes how providing a surface anti-fouling layer with a fine uneven structure with a surface roughness Sa of 1 nm or more and 1 mm or less on the material surface diffuses fingerprints through capillary action and reduces their visibility.

Japanese Patent Application Laid-Open No. 2004-217950 Japanese Patent Application Laid-Open No. 2000-265526 Japanese Patent Application Laid-Open No. 2018-165394 US2015/0239023 publication

Dirt such as limescale accumulates as the dirt adheres and dries repeatedly during daily use, posing the problem of requiring stronger wiping force or more frequent wiping to remove the dirt. Dirt tends to accumulate particularly easily on areas that come into contact with water for extended periods during daily use, such as the periphery of a faucet spout or the base of a countertop faucet, making it difficult to remove even when a surface layer (e.g., a monolayer) is formed.

The inventors have discovered that by providing a water-repellent surface layer with a micrometer-order uneven structure on the surface of a faucet, accumulated stains such as limescale can be removed with less force or fewer wipes than when a smooth surface layer is provided. The present invention is based on this finding.

The faucet according to the present invention comprises:
a substrate and a surface layer on the substrate,
The surface of the portion having the surface layer has a root mean square height (Sq) defined in JIS B 0681-2 (2018) of 0.04 μm or more and 1 μm or less,
The uneven structure has a contour curved surface distortion (Ssk) of -1 or more and 5 or less, and an autocorrelation length (Sal) of 10 μm or more and 50 μm or less,
The surface layer is water-repellent, and is characterized in that the end point of the surface layer is a point at which, in a profile obtained by XPS depth direction analysis, the absolute value of the difference between the carbon atom concentration at a certain measurement point and the carbon atom concentration at the immediately preceding measurement point becomes 1.0 at% or less, and the sputtering time from the start of sputtering to the end point is 5 minutes or less.

The present invention provides a faucet that can remove accumulated dirt such as limescale with less force or fewer wipes.

1 is a schematic diagram showing the basic configuration of a member according to the present invention. 1 is a perspective view of a faucet, which is an example of an article to which a member according to the present invention is applied, showing the areas (bottom and back) of the faucet to which the surface of a member according to the present invention is preferably applied.

Component according to the present invention As shown in Figure 1, the faucet 1 according to the present invention comprises a substrate 10 and a surface layer 40 on the substrate 10. The component 1 may further include an intermediate layer 30 and/or a colored layer 20 between the substrate 10 and the surface layer 40.

The surface of the faucet 1, typically the surface of the surface layer 40, is shaped as specified in JIS B 0681-2 (2018).
The root mean square height (Sq) is 0.04 μm or more and 1 μm or less,
The uneven structure is characterized in that the distortion (Ssk) of the contour curved surface is -1 or more and 5 or less, and the autocorrelation length (Sal) is 10 μm or more and 50 μm or less.

By having a water-repellent surface shape with such a micrometer-order uneven structure, accumulated dirt such as limescale can be removed with less force or fewer wiping operations than when a surface has a smooth shape. The reason why the water-repellent surface layer with the above-mentioned uneven structure has such good limescale removal properties will be explained below through the mechanism of action. The surface shape of the component can be obtained by measuring the shape of the surface layer 40.
The relief structure is preferably as follows:
The root mean square height (Sq) is 0.10 μm or more and 1 μm or less,
The distortion (Ssk) of the contour curved surface is -1 or more and 0 or less, and the autocorrelation length (Sal) is 20 μm or more and 50 μm or less.
The material and properties (water repellency) of the surface layer 40 will be described later.

The mechanism by which limescale is removed from the surface of a component will be explained based on the properties and surface shape of the component. However, the following explanation is hypothetical and is not intended to limit the present invention in any way.
Since water stains on the surface of water-repellent materials do not spread by wetting, they form small, thick scales. When wiping to remove this scale, if it is not chemically bonded to the water-repellent surface, peeling occurs at the interface with the water-repellent surface, making it easier to remove than scale on hydrophilic surfaces, which is removed by abrasion. For this reason, water-repellent materials are easier to remove scale from than hydrophilic materials.
Furthermore, even if a single scale is formed on a hydrophilic material, it takes on a wet, spread shape and is harder than scale formed on a water-repellent material, and is strongly bonded to the substrate. Therefore, whether the substrate is smooth or wavy, it is removed by abrasion when wiping.
When water stains are deposited on a water-repellent material multiple times, the thickness of the stains increases significantly on the surface of the material. If the water-repellent surface is smooth, the stains will not peel off when wiped off, but will be removed by abrasion, which increases the burden of wiping.
On the other hand, if the surface of a water-repellent material has an appropriate undulation, the load on the wiper is significantly reduced. This is because on a undulating surface, the Cassie-Baxter mode increases the contact angle of the water droplets and weakens the pinning effect, so the area of the accumulated water stains is smaller than on a smooth surface, and the bonding strength with the substrate is weaker, making it easier to remove by peeling.
However, even if the surface of the water-repellent material is not smooth, it is difficult to remove accumulated scale when Ssk and Sal are low. Such a surface has many steep valleys, and scale forms inside the valleys, creating an anchor effect that firmly bonds the scale to the substrate.

Measurement of Surface Profile Measurement of the surface profile of a member is performed, for example, as follows.
Before measurement, the components were lightly scrubbed with a urethane sponge using alkaline detergent, and then thoroughly rinsed with ultrapure water. The surface roughness of the components was measured using a laser microscope OLS4500 (Olympus). The measurement area was 645 μm square, and during measurement, the focus was adjusted to the sample surface and height information was acquired in high-precision mode. The upper and lower limits of the measurement height range were set to the height at which the focus was lost and the screen went dark.
The configuration of a laser microscope that can be used to measure the surface shape is, for example, as follows.
Equipment: OLS4500
Product version: 1.1.8
Application version: 1.1.8.3
Light source: 405 nm semiconductor laser Detection system: photomultiplier Objective lens: OLYMPUS MPlan APO N 20X/0.60 LEXT
Measurement range: 645 μm x 645 μm

Calculation of Surface Shape Parameters The measured image is subjected to filtering after tilt correction. For tilt correction, the curved surface correction (automatic) of the analysis software is used. For filtering, an S-filter is used, which removes small lateral components from the surface and results in a first-order surface. The cutoff value of the S-filter is 5 μm.
Details of the analysis software that can be used to calculate the surface shape parameters are as follows:
OLS4500 application (version: 1.1.8.3)
Image processing: Image correction, surface correction, and curved surface correction (automatic) are performed on the software to remove inclinations and other imperfections resulting from the large shape of the substrate (profile cross-sectional area: 0, processing direction: XY directions). Then, a Gaussian filter (S-filter: cutoff value 5 μm) is used.
The surface (three-dimensional) properties of the member are determined using the root mean square height: Sq, the distortion (skewness) of the contour curved surface: Ssk, and the autocorrelation length: Sal as indicators defined in JIS B 0681-2 (2018).

Surface Layer The surface layer 40 of the present invention is a water-repellent layer containing organic molecules, and is transparent and thin enough not to impair the color of the substrate below the surface layer 40. Because the surface layer is a water-repellent layer, the adhesion of limescale is suppressed in faucets that come into contact with tap water containing silicon and calcium (substances that cause limescale), and any limescale that does adhere can be easily removed.

Surface Layer Material In the present invention, the surface layer 40 may be a polymer layer, a low molecular weight layer, or a monolayer.

Monolayer In the present invention, the surface layer 40 is a layer containing a hydrophobic group R and a functional group X that has a coordinating property with a metal element, and the surface layer 40 is preferably a monolayer formed of a single layer, and more preferably a self-assembled monolayer (SAM) consisting of R-X. A self-assembled monolayer is a layer in which molecules are densely assembled, and therefore has excellent water repellency.
The thickness of the SAM is approximately the same as the length of one constituent molecule. Here, "thickness" refers to the length of the SAM along the Z direction. Here, in FIG. 1, the direction from the substrate 10 toward the surface layer 40 is the Z direction. The thickness of the SAM is 10 nm or less, preferably 5 nm or less, and more preferably 3 nm or less. The thickness of the SAM is 0.5 nm or more, preferably 1 nm or more. By using constituent molecules that result in a SAM thickness within this range, the substrate can be efficiently coated, and a faucet with excellent ease of removal of contaminants such as limescale can be obtained.

In a preferred embodiment of the present invention, a SAM is a molecular aggregate formed on a solid surface during the process of organic molecules adsorbing to the solid surface, and the constituent molecules of the aggregate are densely assembled due to interactions between the molecules. The SAM contains hydrocarbon groups. This allows hydrophobic interactions between the molecules, allowing the molecules to densely aggregate, resulting in a faucet with excellent stain removal properties.

In the present invention, the non-polymeric organic ligand R-X comprises a hydrophobic group R and a functional group X that has coordination properties for a metal element. The non-polymeric organic ligand R-X bonds to the underlying surface via the functional group X. Here, "non-polymeric" refers to a compound that does not fall under definition 1.1 in the Glossary of Fundamental Terms in Polymer Science (Japanese translation) by the International Union of Pure and Applied Chemistry (IUPAC) Commission on Macromolecular Nomenclature (i.e., a molecule with a large relative molecular mass that has a structure composed of multiple repeats of units derived, substantially or conceptually, from molecules with a small relative molecular mass. See http://main.spsj.or.jp/c19/iupac/Recommendations/glossary36.html). A SAM is a layer formed using such a non-polymeric organic ligand R-X.

Non-polymeric organic ligand R-X
In a preferred embodiment of the present invention, the surface layer 40 is a layer formed using a non-polymeric organic ligand R-X. The hydrophobic group R is preferably a hydrocarbon group consisting of C and H. Atoms other than carbon may be substituted at one or two positions within the skeleton of the hydrocarbon group of R. Examples of substituted atoms include oxygen, nitrogen, and sulfur. Preferably, one end of R (the end not bonded to X) is a methyl group. This makes the surface of the faucet water-repellent, making it easier to remove dirt.

Specific examples of R (alkyl)
In the present invention, the hydrophobic group R is preferably a hydrocarbon group consisting of C and H. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Furthermore, it may be a chain hydrocarbon or may contain a cyclic hydrocarbon such as an aromatic ring. R is preferably a chain saturated hydrocarbon group, and more preferably a straight-chain saturated hydrocarbon group. Since a chain saturated hydrocarbon group has a flexible molecular chain, it can cover the intermediate layer without gaps and improve water resistance. When R is a chain hydrocarbon group, it is preferably an alkyl group having 6 to 25 carbon atoms. R is more preferably an alkyl group having 10 to 18 carbon atoms. When the number of carbon atoms is large, the interaction between molecules is strong, the molecular spacing of the SAM can be narrowed, and water resistance can be further improved.

Specific examples of R (fluorine)
In the present invention, the hydrophobic group R may contain a halogen atom, such as a fluorine atom. By using a fluorine-containing compound, a highly water-repellent surface can be obtained. However, in order to obtain high water stain removal properties, a surface layer that does not contain halogen atoms is preferred.

Specific Examples of X In the present invention, the functional group X is preferably at least one selected from a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a carboxyl group, a silanol group (or a silanol precursor such as an alkoxysilyl group), a β-diol group, an amino group, a hydroxyl group, a hydroxyamide group, and an α- or β-hydroxycarboxylic acid group.

Carboxyl groups, β-diol groups, amino groups, hydroxyl groups, hydroxyamide groups, and α- or β-hydroxycarboxylic acid groups do not polymerize with each other, but rather coordinate (adsorb) to the metal elements contained in the intermediate layer, forming a dense surface layer.

In a preferred embodiment of the present invention, X is at least one phosphorus-atom-containing functional group selected from the group consisting of a phosphonic acid group, a phosphoric acid group, and a phosphinic acid group, and is more preferably a phosphonic acid group. This makes it possible to efficiently obtain a component that has high water resistance and excellent ease of removing contaminants.

Specific Examples of R-X in Monolayer The organic phosphonic acid compound represented by the general formula R-X is preferably octadecylphosphonic acid, hexadecylphosphonic acid, dodecylphosphonic acid, decylphosphonic acid, octylphosphonic acid, or hexylphosphonic acid, more preferably octadecylphosphonic acid, hexadecylphosphonic acid, dodecylphosphonic acid, or decylphosphonic acid, and even more preferably octadecylphosphonic acid.

In R-X, phosphonic acid may be used as a molecule having a phosphonic acid group; (organic) phosphoric acid as a molecule having a phosphoric acid group; phosphinic acid as a molecule having a phosphinic acid group; carboxylic acid as a molecule having a carboxyl group; protocatechuic acid, gallic acid, dopa, or a catechol (orthohydroxyphenyl) group as a molecule having a β-diol group; amino acid as a molecule having an amino group; alcohol as a molecule having a hydroxyl group; hydroxamic acid as a molecule having a hydroxyamide group; and salicylic acid and quinic acid as molecules having an α- or β-hydroxycarboxylic acid group.

In the present invention, the surface layer 40 may be formed from two or more types of R-X. A surface layer formed from two or more types of R-X means a surface layer formed from a mixture of multiple types of the above-mentioned compounds. Also, in the present invention, the surface layer 40 may contain trace amounts of organic molecules other than R-X, as long as the ease of removing limescale is not impaired.

Intermediate Layer According to a preferred embodiment of the present invention, an intermediate layer 30 may be provided between the surface layer 40 and the substrate 10, or between the surface layer 40 and the colored layer 20. The intermediate layer 30 can provide good adhesion between the surface layer 40 and the substrate 10. A preferred example of the intermediate layer 30 is a layer containing metal atoms and oxygen atoms. In the intermediate layer 30, the metal atoms are bonded to oxygen atoms. In other words, the intermediate layer 30 contains the metal element in an oxidized state. In the present invention, the intermediate layer 30 is preferably at least one selected from the group consisting of Cr, Zr, and Si. Furthermore, the intermediate layer 30 is preferably of a thickness similar to or less than that of the surface layer 40 so as not to impair the color of the base.

Colored Layer In the present invention, the colored layer is a layer that exhibits a color such that the absolute value of at least one of ΔL*, Δa*, and Δb* of the surface of a member having the colored layer exceeds 0, as compared to the surface of a member not having the colored layer. In the present invention, the colored layer is preferably a layer containing Zr or C. In the present invention, it is more preferable that the colored layer is an inorganic layer containing Zr or C, in terms of excellent durability of the member.

Substrate In the present invention, the material of the substrate is not particularly limited, and for example, a material that is generally used as a substrate for a faucet can be used.

Region 10a of substrate 10
The substrate 10 includes a support material 10a. The material of the support material 10a may be metal, resin, ceramic, earthenware, or glass.

Region 10b of substrate 10
The substrate 10 may also be provided with a region 10b. The region 10b may be, for example, a metal-containing layer or a layer of an inorganic compound primarily containing carbon, formed by metal plating or physical vapor deposition (PVD). The region 10b may be composed solely of metal elements, or may be contained in the form of a metal nitride (e.g., TiN, TiAlN, etc.), a metal carbide (e.g., CrC, etc.), a metal carbonitride (e.g., TiCN, CrCN, ZrCN, ZrGaCN, etc.), or the like. The region 10b may be formed directly on the support material 10a, or a different layer may be included between the region 10b and the support material 10a. Examples of substrates 10 provided with the region 10b include metal-plated products in which the region 10b is provided by metal plating on a support material 10a made of brass or resin. On the other hand, examples of substrates 10 not provided with the region 10b include metal molded products such as stainless steel (SUS). The surface texture of the substrate 10 is not particularly limited, but preferably has a three-dimensional shape.

When the surface layer is made of an organic phosphonic acid compound, region 10b preferably includes a layer containing oxygen atoms and one or more metal atoms selected from Ti, Zr, Cr, and Al.

When the surface layer is made of an organic phosphonic acid compound, region 10b preferably includes a layer containing oxygen atoms and one or more metal atoms selected from Ti, Zr, Cr, and Al.

Identification of Component Structure In the present invention, the component structure is identified by first identifying the elements constituting the surface layer 40 using XPS measurement, and confirming the presence of the hydrophobic group R and the functional group X using mass spectrometry. The thicknesses of the surface layer 40 and the intermediate layer 30 are confirmed by sputtering while measuring the abundance ratio of the elements using XPS measurement. Next, the colored layer 20 and the substrate 10 are identified by observing the cross section using an SEM to identify their presence and boundaries. Prior to the above measurements, a pretreatment is performed to remove any dirt adhering to the surface.

Pretreatment: In the present invention, the surface of the faucet is cleaned before measurement to thoroughly remove any dirt adhering to the surface. For example, after wiping with ethanol and cleaning with a sponge using a neutral detergent, the surface is thoroughly rinsed with ultrapure water. Furthermore, for faucets with high surface roughness, such as those with hairline or shot blasting treatments, the measurement site should be selected to be as smooth as possible. A highly smooth area is one where the light is diffused more than a rough area, and thus where the L* value measured by the SCE method is less than 5, and does not include the specular reflection component when measuring color difference.

Identification of surface layer Identification of R and X of surface layer

In the present invention, the surface layer is examined in detail using the following procedure. First, surface elemental analysis is performed using XPS analysis to identify the elements contained in the surface layer. Next, mass spectrometry is used to identify the molecular structure from the mass-to-charge ratio (m/z) derived from the molecules of the components present on the surface. Mass spectrometry can be performed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) or high-resolution mass spectrometry (HR-MS). Here, high-resolution mass spectrometry refers to a method that can measure mass resolution with an accuracy of 0.0001 u (u: unified atomic mass units) or less than 0.0001 Da, and can estimate elemental composition from the exact mass. Examples of HR-MS include double-focusing mass spectrometry, time-of-flight tandem mass spectrometry (Q-TOF-MS), Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), and orbitrap mass spectrometry. In the present invention, time-of-flight tandem mass spectrometry (Q-TOF-MS) is used. For mass spectrometry, HR-MS is preferably used if sufficient amounts of R and X can be recovered from the component. On the other hand, if sufficient amounts of R and X cannot be recovered from the component due to reasons such as the component's small size, TOF-SIMS is preferably used. When using mass spectrometry, the presence of R and X can be confirmed by detecting the ion intensity of the m/z corresponding to the ionized R and X. Here, the ion intensity is considered to have been detected when the signal is at least three times the average value of the signal in the range 50 Da around the lowest m/z value within the range for which ion intensity is calculated within the measurement range.

TOF-SIMS Measurement Conditions for Identifying R and X in the Surface Layer A time-of-flight secondary ion mass spectrometry (TOF-SIMS) device, such as a TOF-SIMS5 (manufactured by ION-TOF, Inc.), is used. The measurement conditions are as follows: irradiated primary ions: 209Bi3++, primary ion acceleration voltage: 25 kV, pulse width: 10.5 or 7.8 ns, bunching present, no charge neutralization, post-acceleration: 9.5 kV, measurement range (area): approximately 500 x 500 μm2, detected secondary ions: positive, negative, cycle time: 110 μs, number of scans: 16. As a measurement result, a secondary ion mass spectrum (m/z) derived from R and X is obtained. The secondary ion mass spectrum is expressed as the mass-to-charge ratio (m/z) on the horizontal axis and the intensity (count) of the detected ions on the vertical axis.

HR/MS Measurement Conditions for Identifying R and X in the Surface Layer A time-of-flight tandem mass spectrometer (Q-TOF-MS), for example, a Triple TOF 4600 (manufactured by SCIEX) is used as the high-resolution mass spectrometer. For example, the cut-out substrate is immersed in ethanol, the components (R and X) used to form the surface layer are extracted, and the unnecessary components are filtered and then transferred to a vial (approximately 1 mL) before measurement. The measurement conditions are, for example, ion source: ESI/Duo Spray Ion Source, ion mode (positive/negative), IS voltage (-4500 V), source temperature (600 ° C), DP (100 V), CE (40 V), and MS/MS measurement is performed. As a measurement result, an MS/MS spectrum is obtained. The MS/MS spectrum is expressed as the mass-to-charge ratio (m/z) on the horizontal axis and the intensity (count) of detected ions on the vertical axis.

Measurement of each atomic concentration The composition of the surface layer of each sample is determined by X-ray photoelectron spectroscopy (XPS). Before measurement, the sample is scrubbed with a sponge using a neutral detergent and then thoroughly rinsed with ultrapure water. A PHI Qantera II (manufactured by ULVAC-PHI) is preferably used as the XPS device. A spectrum is obtained by measuring each element under the following "XPS element fraction measurement conditions" and "XPS sputter analysis condition 1."
The concentration of the detected atoms is calculated from the obtained spectrum using data analysis software PHI MultiPuk (manufactured by ULVAC-PHI). The obtained spectrum is subjected to background removal using the Shirely method for peaks based on the electron orbitals of each measured atom, and then the peak area intensity is calculated and corrected by dividing it by a sensitivity coefficient specific to the device that is preset in the data analysis software. The ratio of the corrected peak area of a given element to the total corrected peak area intensity of all measured element species is defined as the atomic concentration of the target, and is calculated in at.%.

Conditions for measuring element fraction by XPS X-ray conditions: monochromatic AlKα ray, 25 W, 15 kV
Analysis area: 100μmφ
Neutralization gun conditions: 1.0 V, 10 μA
Photoelectron take-off angle: 45°
Time Per Step: 50ms
Sweep: 5 times Pass energy: 112eV
Analyzed elements (energy range): Zr3d (177-187 eV), C1s (281-296 eV), N1s (394-406 eV), O1s (524-540 eV), Cr2p3 (572-582 eV), Ti2p (452-463 eV), Si2p (98-108 eV)

Condition 1 for XPS sputtering analysis (hereinafter referred to as "sputtering condition 1")
Inert gas species: Ar
Sputtering voltage: 500 V
Sputtering area: 2 mm x 2 mm
Sputtering interval: 10 seconds. The sputtering voltage refers to the voltage applied to the Ar ion gun, the sputtering range refers to the surface area removed by sputtering, and the sputtering cycle refers to the time during which Ar gas is continuously irradiated for each measurement in the depth direction, and the total sputtering cycle is the sputtering time.

The surface layer is characterized in that the end point of the surface layer is the point where the absolute value of the difference between the carbon atom concentration at a certain measurement point and the carbon atom concentration at the previous measurement point becomes 1.0 at% or less in XPS measurement under sputtering condition 1, and the sputtering time from the start to the end point is 5 minutes or less, preferably 3 minutes or less. This time is an index of the thickness of the surface layer.

Preferred Carbon Atom Concentration of Surface Layer 40 In the present invention, the carbon atom concentration of the surface layer 40 is preferably 35 at% or more, more preferably 40 at% or more, even more preferably 43 at% or more, and most preferably 45 at% or more. Furthermore, the carbon atom concentration is preferably less than 70 at%, more preferably 65 at% or less, and even more preferably 60 at% or less. A suitable range of the carbon atom concentration can be achieved by appropriately combining these upper and lower limit values. By setting the carbon atom concentration within this range, the ease of removing scale can be improved.

Preferred Phosphorus Atom Concentration of Surface Layer 40 In the present invention, the phosphorus atom concentration of the surface layer 40 is preferably 1.0 at% or more and less than 10 at%. By setting the phosphorus atom concentration in this range, the surface layer 40 is shown to be dense. This makes it possible to obtain a faucet that has sufficient water resistance and excellent limescale removability. More preferably, the phosphorus atom concentration is 1.5 at% or more and less than 10 at%. This further improves water resistance and limescale removability.

water repellency

The faucet of the present invention preferably has a water droplet contact angle on its surface of 90° or more, and more preferably 100° or more. The water droplet contact angle refers to a static contact angle, and is determined by dropping a 2 μl water droplet onto a substrate and photographing the droplet from the side of the substrate after 1 second. A contact angle meter (model number: SDMs-401, manufactured by Kyowa Interface Science Co., Ltd.), for example, can be used as a measuring device.

Identifying an Intermediate Layer In the present invention, the presence of an intermediate layer can be confirmed by XPS depth profile analysis. First, XPS measurement is performed for 10 minutes under (sputtering condition 1), and at the point where the difference in carbon atom detection from the previous measurement point is 1.0 at% or less, metal elements detected at 10 at% or more are confirmed. If the concentration of the element is 3.0 at% or less after 10 minutes of sputtering, the range in which the element exists can be confirmed as an intermediate layer. If the concentration of the element does not decrease to 3.0 at% or less after 5 minutes of sputtering, the component is deemed not to have an intermediate layer.

Identification of Colored Layer and Substrate: The substrate, which may include a colored layer, is cut in the cross-sectional direction and cross-sectional milled using an ion milling device to obtain a smooth cross-section. The cross-section is observed using a scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX) to identify the colored layer and the substrate. An SEM image is taken of the observation area so that the colored layer and the substrate are included. EDX mapping analysis of the SEM image allows visual confirmation of the elemental distribution of the colored layer and the substrate. The boundary surface where the elemental distribution differs is identified as the boundary surface between the colored layer and the substrate.

The faucet of the present invention is manufactured by the following steps:
(a) The surface has a root mean square height (Sq) of 0.04 μm or more and 1 μm or less as defined in JIS B 0681-2 (2018),
a step of preparing a substrate having a concave-convex structure characterized in that the distortion (Ssk) of the contour curved surface is -1 or more and 5 or less, and the autocorrelation length (Sal) is 10 μm or more and 50 μm or less, or a substrate provided with a colored layer having the concave-convex structure;
(b) forming a surface layer on the surface of the substrate having a concave-convex structure or the colored layer having a concave-convex structure.
The uneven structure on the substrate surface is on the order of micrometers, and the thickness of the surface layer is on the order of nanometers, so the above-described manufacturing method makes it possible to form the surface layer without impairing the water repellency.

The method may further include a step of plating the surface of the substrate having the uneven structure between steps (a) and (b).

In the present invention, preferably, the step (a) comprises:
(a1) providing a support material;
(a2) the surface of the support material has a root mean square height (Sq) of 0.04 μm or more and 1 μm or less as defined in JIS B 0681-2 (2018);
and forming a concave-convex structure having a contour curved surface distortion (Ssk) of -1 or more and 5 or less and an autocorrelation length (Sal) of 10 μm or more, thereby producing the substrate.

In the present invention, preferably, a step of plating the surface of the support material to produce a support material having a plated layer on its surface is further included between steps (a1) and (a2).

Use Environment of Faucet The faucet of the present invention is used in an environment where water (for example, domestic water or industrial water) splashes on its surface.

In the present invention, environments subject to water splashes are places where water is used, such as homes and public facilities such as parks, commercial facilities, and offices. Such places preferably include bathrooms, toilet spaces, restrooms, washrooms, and kitchens.

The faucet of the present invention preferably has a surface layer formed in areas of the faucet that are in contact with water for a relatively long period of time. In such areas, the formation of limescale is promoted at the interface between the surface of the faucet, water, and air. Therefore, by applying the surface of the present invention to such areas, the effects of the present invention are maximized, and accumulated limescale and other dirt can be removed with less force or fewer wipes.

Areas where the present invention is particularly effective include, for example, the periphery of the spout, as indicated by the arrow in Figure 2, and the base of a countertop faucet (for example, the part or component that comes into contact with the washbasin). These areas are harder to reach and harder to apply force to when cleaning than the front or top surface of the faucet, so limescale tends to accumulate and become noticeable. By providing these areas with the textured shape shown in the present invention, limescale can be removed with fewer wipes, preserving the appearance of the component.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

Fabrication of Members (Example 1)
After nickel plating the brass plate, a roughened surface was formed on the surface using a dry blasting machine (product name: Pneumatic Blaster SGF-4(B), manufactured by Fuji Manufacturing Co., Ltd.), and then chrome plating was performed to prepare a substrate.
The blasting conditions were as follows: a round blast gun with a diameter of 12 mm was used, the air pressure was 0.20 MPa, the projection distance was 200 mm, the processing time was 1 s/cm2, and the abrasive used was FZB120 (manufactured by Fuji Manufacturing Co., Ltd.).
Next, a surface layer having hydrocarbon groups was formed by the following procedure.
First, to remove dirt from the surface of the substrate, the substrate was subjected to ultrasonic cleaning with an aqueous solution containing alkaline detergent, and then the surface of the substrate was subjected to running water to remove the detergent.Furthermore, the substrate was immersed in ion-exchanged water, rinsed with ultrasonic cleaning, and then the water was removed with an air duster.
Next, the substrate was immersed in a 2.5 M aqueous solution of sodium hydroxide at 50° C. for 5 minutes, and then thoroughly rinsed with ion-exchanged water.
The treatment agent used to form the surface layer was a solution of octadecylphosphonic acid (ODPA) (product code: O0371, manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in ethanol (Wako Pure Chemical Industries, Ltd., Fujifilm). The substrate was immersed in the treatment agent for at least one minute and then washed with ethanol. The substrate was then dried in a dryer at 120°C for 10 minutes to form an organic layer on the surface of the substrate. In this way, the member of Example 1 was produced.

Example 2
A brass plate was rubbed in one direction with sandpaper (product name: FRCC-SDS180, manufactured by Nihon Kenshi) about 20 times to form streaky irregularities on the surface, and then nickel-chrome plated to prepare a substrate.
Next, an organic layer was formed on the surface of this substrate in the same manner as in Example 1. In this way, a member of Example 2 was produced.

( Comparative Example 7 )
A member of Comparative Example 7 was produced in the same manner as in Example 2, except that the sandpaper used was changed to a different one (product name: FRCC-SDS600, manufactured by Nihon Kenshi).

Example 4
A brass plate was rubbed in one direction with sandpaper (product name: FRCC-SDS180, manufactured by Nihon Kenshi) about 20 times to form streaky irregularities on the surface, and then nickel-chrome plated to prepare a substrate.
Next, a surface layer having fluorocarbon groups was formed by the following procedure.
First, to remove dirt from the surface of the substrate, the substrate was subjected to ultrasonic cleaning with an aqueous solution containing alkaline detergent, and then the surface of the substrate was subjected to running water to remove the detergent.Furthermore, the substrate was immersed in ion-exchanged water, rinsed with ultrasonic cleaning, and then the water was removed with an air duster.
Next, the substrate was irradiated with ultraviolet light (wavelength: 254 nm, irradiation intensity: approximately 15 mW/cm 2 ) for 10 minutes.
Thereafter, a solution of a silicone primer (product name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) dissolved in isopropyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was impregnated into a nonwoven fabric (product name: Bemcot M3-II, manufactured by Asahi Kasei Co., Ltd.), spread over the entire substrate, and then allowed to air dry for 10 minutes to form an intermediate layer.
A coating agent containing a fluorinated alkyl group (product name: SURECO2101S, manufactured by AGC) was used as the treatment agent for forming the surface layer. This treatment agent was impregnated into a nonwoven fabric (product name: BEMCOT M3-II, manufactured by Asahi Kasei), spread over the entire substrate, and then dried in a dryer at 120°C for 30 minutes.
In this way, the member of Example 4 was produced.

( Comparative Example 8 )
A member of Comparative Example 8 was produced in the same manner as in Example 4, except that the sandpaper used was changed to a different one (product name: FRCC-SDS600, manufactured by Nihon Kenshi).

Example 6
A surface irregularity and an organic layer were formed on the underside of the wall-mounted single-lever faucet (product number: TKS05315J, manufactured by TOTO) shown in FIG. 2 in the same manner as in Example 2, to produce a member of Example 6.

(Comparative Example 1)
The brass plate was nickel-chrome plated and then the surface was buffed using an automatic polishing machine (manufactured by Buhler Co., Ltd.) to prepare a substrate. Alumina particles with an average particle size of 0.05 μm were used as abrasive particles.
Next, a surface layer was formed on the surface of this substrate in the same manner as in Example 1, to prepare a member of Comparative Example 1.

(Comparative Example 2)
The substrate used in Comparative Example 1 was used, and a surface layer was formed on the surface of this substrate in the same manner as in Example 4 to prepare a member of Comparative Example 2.

(Comparative Example 3)
A brass plate was nickel-plated, the surface was hairline-finished, and then chrome-plated to prepare a substrate.
Next, a surface layer was formed on the surface of this substrate in the same manner as in Example 1, to prepare a member of Comparative Example 3.

(Comparative Example 4)
The substrate used in Comparative Example 1 was used, and a surface layer was formed on the surface of this substrate in the same manner as in Example 4, to prepare a member of Comparative Example 4.

(Comparative Example 5)
A member of Comparative Example 5 was produced by carrying out the same treatment as in Example 1, except that the air pressure of the dry blasting device was set to 0.25 MPa.

(Comparative Example 6)
A member of Comparative Example 6 was produced by carrying out the same treatment as in Example 1, except that the air pressure of the dry blasting device was set to 0.30 MPa.

Performance Tests The members prepared as described above were used as samples to carry out the following tests.

Limescale Removal Test 200 μl of tap water was dropped onto the surface of each sample heated to 50°C in a drying oven, and the sample was left to stand until the liquid dried. This operation constituted one cycle. The same operation was repeated, i.e., tap water was further dropped onto the limescale formed after one cycle, and the sample was allowed to dry, forming limescale for two cycles. The same operation was then repeated to create limescale for three and five cycles. The samples on which limescale had formed were evaluated according to the following procedure.

(i) A dry cloth was used to apply a light load (80 gf/cm 2 ) to the surface of the sample, and the cloth was then slid back and forth five times.
(ii) If the removal of the scale was confirmed, the test was terminated. If the scale remained, (i) was repeated.
The removal of water stains was determined by rinsing the surface of the sample with running water, removing the water with an air duster, and then visually checking whether water stains remained on the surface of the sample.

Based on the number of sliding movements required to remove the scale by steps (i) and (ii), the scale removal performance was evaluated as follows.
When it was possible to remove it after 5 tries, it received 3 points. When it was possible to remove it after 10 tries, it received 2 points. When it was possible to remove it after 15 tries, it received 1 point. When it was not possible to remove it after 15 tries, it received 0 points. The evaluation results are shown in Table 1.

Measurement of Properties Each of the members prepared as described above was used as a sample to carry out the following measurements.

Measurement of Surface Profile Before measurement, each sample was lightly scrubbed with a urethane sponge using alkaline detergent, and then thoroughly rinsed with ultrapure water. The surface roughness of each sample was measured using a laser microscope OLS4500 (Olympus). The measurement area was 645 μm square. During measurement, the focus was adjusted to the sample surface, and height information was acquired in high-precision mode. The upper and lower limits of the measurement height range were set to the height at which the image became out of focus and went dark.
The laser microscope used had the following configuration:
Equipment: OLS4500
Product version: 1.1.8
Application version: 1.1.8.3
Light source: 405 nm semiconductor laser Detection system: photomultiplier Objective lens: OLYMPUS MPlan APO N 20X/0.60 LEXT
Measurement range: 645 μm x 645 μm

Calculation of surface shape parameters The measured images were subjected to filtering after tilt correction. For tilt correction, the curved surface correction (automatic) function of the analysis software was used. For filtering, an S-filter was used to remove small lateral components from the surface and obtain a first-order surface. The cutoff value of the S-filter was 5 μm.
Details of the analysis software used are as follows:
OLS4500 application (version: 1.1.8.3)
Image processing: Image correction, surface correction, and curved surface correction (automatic) were performed on the software to remove inclinations and other imperfections resulting from the large shape of the substrate (profile cross-sectional area: 0, processing direction: XY directions). Then, a Gaussian filter (S-filter: cutoff value 5 μm) was used.
The surface (three-dimensional) properties of each sample were determined using the root mean square height (Sq), contour curve distortion (Ssk), and autocorrelation length (Sal) as indices defined in JIS B 0681-2 (2018). The measured values of Sq, Ssk, and Sal are listed in Table 1.

Measurement of each atomic concentration In the XPS measurement under the above (sputtering condition 1), the point at which the difference in the detected carbon atoms from the previous measurement point became 1.0 at % or less was defined as the end point of the surface layer, and the sputtering time up to that point was shown in Table 1.

10: Substrate; 10a: One region of the substrate; 10b: Another region of the substrate; 20: Colored layer; 30: Intermediate layer; 40: Surface layer

Claims (4)

A faucet comprising a substrate and a surface layer on the substrate,
the substrate comprises a metal;
The surface of the portion of the faucet that has the surface layer has a root mean square height (Sq) defined in JIS B 0681-2 (2018) of 0.10 μm or more and 1 μm or less,
The uneven structure has a contour curved surface distortion (Ssk) of -1 or more and 0 or less, and an autocorrelation length (Sal) of 20 μm or more and 50 μm or less,
The surface layer is a water-repellent polymer layer, a low-molecular-weight layer, or a monomolecular-weight layer , and in a profile obtained by XPS depth direction analysis measured under the conditions described below in "Conditions for measuring element fraction by XPS" and "Sputtering condition 1," the endpoint of the surface layer is the point where the absolute value of the difference between the carbon atom concentration at a certain measurement point and the carbon atom concentration at the measurement point immediately preceding that point becomes 1.0 at% or less, and the sputtering time from the start of sputtering to the endpoint is 5 minutes or less.

XPS element fraction measurement conditions
X-ray conditions: monochromatic AlKα radiation, 25 W, 15 kV
Analysis area: 100μmφ
Neutralization gun conditions: 1.0 V, 10 μA
Photoelectron take-off angle: 45°
Time Per Step: 50ms
Sweep: 5 times
Pass energy: 112eV
Analyzed elements (energy range): Zr3d (177-187 eV), C1s (281-296 eV), N1s (394-406 eV), O1s (524-540 eV), Cr2p3 (572-582 eV), Ti2p (452-463 eV), Si2p (98-108 eV)

Sputtering condition 1
Inert gas species: Ar
Sputtering voltage: 500 V
Sputtering area: 2 mm x 2 mm
Sputtering interval: 10 seconds
The faucet of claim 1, wherein the end point of the surface layer is determined as the point where the absolute value of the difference between the carbon atom concentration at a certain measurement point and the carbon atom concentration at the previous measurement point in the profile obtained by the XPS depth direction analysis of the surface layer is 1.0 at% or less, and the sputtering time from the start of sputtering to the end point is 3 minutes or less. The faucet according to claim 1 or 2, further comprising an intermediate layer between the surface layer and the base material. A tap according to any one of claims 1 to 3, the surface of which is applied as the underside or backside of the tap .