Coating composition and coating film

Abstract

The purpose of the present disclosure is to provide a coating composition which is capable of forming a display that can exhibit high retroreflective performance (especially, retroreflective performance at a high incidence angle) without being misidentified as a white line even in cases where the display is formed on a road surface.　A coating composition according to the present disclosure is for a detection object to be sensed with near-infrared light, and contains a coating film-forming resin (A), a color pigment (B) and aggregate (E). The color pigment (B) comprises at least one pigment that is selected from the group consisting of a white color pigment having a near-infrared reflectance of 60% or more, a chromatic color pigment having a near-infrared reflectance of 50% or more, and a black color pigment having a near-infrared reflectance of 30% or more, if the reflectance in the wavelength range from 800 nm to 2,500 nm is taken as the near-infrared reflectance; and the aggregate (E) contains aggregate (E1) which has a near-infrared reflectance of 5% or more.

Description

Coating composition and coating film

[0001] The present invention relates to a coating composition and a coating film, and more particularly to a coating composition and a coating film for use in sensing an object to be detected using near-infrared light.

[0002] Development of automated guided vehicle (AGV) systems is underway with the aim of automating transportation and reducing labor. AGVs are defined in JIS D 6801 as "vehicles that travel automatically within a certain area and have the function of transporting items other than people, such as cargo, and that are not to be used on roads defined by the Road Traffic Act." AGVs are classified into three types: route-guided types, in which the vehicle's position is controlled by some kind of guidance means; autonomous types, in which the vehicle itself has self-position estimation and navigation control functions; and following types, in which the vehicle moves by following a person or vehicle ahead.

[0003] Patent Document 1 describes a cooperative guidance system that includes a processor that applies paint containing a crystalline rare earth phosphor that can convert light into electromagnetic energy to a public road surface, irradiates the painted surface with light, detects the generated electromagnetic energy, and converts it into a processed signal to determine the vehicle's operating characteristics or the characteristics of the public road surface.

[0004] Furthermore, Patent Document 2 describes a pigment that reflects more than 60% of electromagnetic radiation having a wavelength of 850 nm or more and 950 nm or less.

[0005] Patent Document 3 describes an electromagnetic wave absorbing ink composition comprising electromagnetic wave absorbing fine particles, a dispersant, a resin, and a solvent.

[0006] JP-T-2019-513198 A JP-A-2019-131791 JP-A-2002-188031

[0007] In the route guidance system, the vehicle position is typically controlled using magnetism, electromagnetic induction, light reflection, or the like. Among these, a guidance system using light reflection has attracted attention because it allows for easy route setting and modification. In a guidance system using light reflection, accurate position recognition is required, requiring accurate recognition of reflected light from a specific illuminated object such as a marker. Therefore, it is desirable for such a specific illuminated object to exhibit retroreflectivity (the property of reflecting light in the same direction as the incident direction).

[0008] Furthermore, the autonomous mobile vehicle uses LiDAR (Laser Imaging Detection and Ranging) technology to estimate its own position. LiDAR is a type of optical remote sensing technology that irradiates an object, such as a road surface, with near-infrared light, visible light, and / or ultraviolet light, and measures the light reflected and / or scattered by the object to detect the distance and direction from the irradiation position to the object. LiDAR is widely used not only in AGVs, but also in autonomous driving technology for automobiles, electronic devices, and various industries. Even when applying LiDAR technology to AGVs and autonomous driving technology, it is desirable for objects, such as road surfaces, to exhibit retroreflective properties. In particular, AGVs and autonomous driving are expected to irradiate a road surface at a distance from the vehicle with laser light and detect the reflected light, so it is necessary to be able to handle cases where the angle of incidence is high. At low angles of incidence, the difference between the angle of incidence and the angle of reflection is small, so retroreflectivity can be achieved relatively easily, but at high angles of incidence, it becomes difficult to achieve retroreflectivity because it is necessary to reflect light in a direction significantly different from that of normal total reflection. The angle of incidence is the angle from the normal to the reflective surface.

[0009] One example of a method for producing retroreflectivity in markers, road surfaces, and the like is to apply paint containing glass beads. However, because glass beads also strongly reflect visible light, they may be mistaken for white lines, particularly on road surfaces, when irradiated with strong light such as sunlight or automobile headlights. On the other hand, reducing the brightness of the paint reduces LiDAR detectability. With the above-mentioned conventionally known techniques, it has been difficult to form a marking that exhibits high retroreflectivity (especially at high angles of incidence) without being mistaken for a white line.

[0010] The present disclosure has been made in consideration of the above circumstances, and aims to provide a paint composition that is capable of forming markings that, even when formed on a road surface, will not be mistaken for white lines and will exhibit high retroreflectivity (particularly retroreflectivity at high angles of incidence).

[0011] The present invention includes the following inventions: [1] A coating composition for a detection target in near-infrared light sensing, comprising a film-forming resin (A), a colored pigment (B), and an aggregate (E), wherein the colored pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance, and the aggregate (E) comprises an aggregate (E1) having a near-infrared reflectance of 5% or more. [2] The coating composition for a detection target in near-infrared light sensing according to [1], wherein the aggregate (E1) has an average particle size of 50 μm or more. [3] The coating composition for a detection target in sensing using near-infrared light according to [1] or [2], wherein the mass concentration of the aggregate (E) is 10% by mass or more and 70% by mass or less. [4] The coating composition for a detection target in sensing using near-infrared light according to any one of [1] to [3], wherein the chromatic pigment comprises at least one pigment selected from the group consisting of reddish pigments, yellowish pigments, and blueish pigments. [5] The coating composition for a detection target in sensing using near-infrared light according to any one of [1] to [4], wherein the reddish pigment and the yellowish pigment each comprise an organic pigment and / or an inorganic pigment. [6] The coating composition for a detection target in sensing using near-infrared light according to any one of [1] to [5], wherein the color pigment (B) comprises at least one selected from the group consisting of: a white pigment having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1,550 nm; an organic red pigment having a spectral reflectance of 50% or more at the wavelength; an inorganic red pigment having a spectral reflectance of 20% or more at the wavelength; an organic yellow pigment having a spectral reflectance of 60% or more at the wavelength; an inorganic yellow pigment having a spectral reflectance of 20% or more at the wavelength; a blue pigment having a spectral reflectance of 40% or more at the wavelength; an organic black pigment having a spectral reflectance of 30% or more at the wavelength; and an inorganic black pigment having a spectral reflectance of 15% or more at the wavelength.[7] A coating composition for a detection target in sensing using near-infrared light according to any one of [1] to [6], wherein the brightness of the coating film formed is 80 or less. [8] A coating film for a detection target in sensing using near-infrared light, wherein the near-infrared reflectance in the wavelength range of 800 to 2,500 nm is 15% or more, and the root-mean-square height (Sq) measured in accordance with ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured in accordance with ISO 25178 is 10 μm or more. [9] A coating film for a detection target in sensing using near-infrared light, formed from the coating composition according to any one of [1] to [7].

[10] The coating film for a detection target in sensing using near-infrared light according to [9], which has a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2,500 nm, and has a root-mean-square height (Sq) of 10 μm or more as measured in accordance with ISO 25178 and / or an arithmetic mean height (Sa) of 10 μm or more as measured in accordance with ISO 25178.

[11] The coating film for a detection target in sensing using near-infrared light according to any one of [9], which has a spectral reflectance of 20% or more at wavelengths of 905 nm and / or 1,550 nm, and has a root-mean-square height (Sq) of 10 μm or more as measured in accordance with ISO 25178 and / or an arithmetic mean height (Sa) of 10 μm or more as measured in accordance with ISO 25178.

[12] A detection object having a coating film formed using the coating composition for a detection object according to any one of [1] to [7].

[13] A sensing method for measuring the distance between a vehicle and a detection object, which comprises irradiating a traveling vehicle with near-infrared light of a specific wavelength, causing the light to be reflected by the detection object, detecting the reflected light, and calculating the distance from the vehicle to the detection object based on the time required for reflection, wherein the coated object is obtained by coating the coated object with the coating composition according to any one of claims [1] to [7].

[14] A sensing method for measuring the distance between a vehicle and an object to be detected, in which near-infrared light of a specific wavelength is irradiated from a traveling vehicle, which is reflected by the object to be detected, the reflected light is detected, and the distance from the vehicle to the object to be detected is calculated from the frequency difference between the irradiated light and the reflected light, wherein the coated object is obtained by coating the coated object with the coating composition described in any one of [1] to [7].

[15] A method for producing a coating film, comprising: applying a first coating composition onto a road surface to obtain a coating film; and drying the coating film to obtain a coating film for use as a detection target in sensing using near-infrared light, wherein the first coating composition comprises a coating film-forming resin (A), a color pigment (B), and an aggregate (E), and the color pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance, and the aggregate (E) comprises an aggregate (E1) having a near-infrared reflectance of 5% or more.

[16] A method for producing a coating film, comprising: applying a second coating composition onto a road surface to obtain a second coating film; scattering aggregate (E) onto the second coating film; and drying the second coating film to obtain a coating film for a detection target in sensing using near-infrared light, wherein the second coating composition comprises a coating film-forming resin (A) and a color pigment (B), and the color pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance, and the aggregate (E) comprises aggregate (E1) having a near-infrared reflectance of 5% or more.

[17] A method comprising: applying a third coating composition onto a road surface to obtain a third coating film; scattering aggregate (E) on the third coating film; and applying a fourth coating composition onto the third coating film onto which the aggregate (E) has been scattered to obtain a fourth coating film; and drying the third and fourth coating films to obtain a coating film for a detection target in sensing using near-infrared light, wherein the third coating composition comprises a coating film-forming resin (A) and a color pigment (B), and the fourth coating composition comprises a coating film-forming resin (A) and a color pigment (B), and the color pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance,

[18] The method for producing a coating film according to any one of

[15] to

[17] , wherein the coating film for a detection target in sensing using near-infrared light has a near-infrared reflectance of 15% or more in a wavelength range of 800 to 2,500 nm, a root-mean-square height (Sq) measured in accordance with ISO 25178 of 10 μm or more, and / or an arithmetic mean height (Sa) measured in accordance with ISO 25178 of 10 μm or more.

[19] The manufacturing method according to any one of

[15] to

[17] , wherein the coating film for a detection target in sensing using near-infrared light has a spectral reflectance of 20% or more at wavelengths of 905 nm and / or 1,550 nm, a root-mean-square height (Sq) measured in accordance with ISO 25178 of 10 μm or more, and / or an arithmetic mean height (Sa) measured in accordance with ISO 25178 of 10 μm or more.

[0012] The coating composition and coating film of the present invention, even when applied to a road surface, can realize a marking that exhibits high retroreflectivity (particularly at high incidence angles) without being mistaken for a white line. Such a marking can improve the detection accuracy of near-infrared rays in LiDAR technology, and preferably can improve the detection accuracy of near-infrared rays in LiDAR technology, particularly at incidence angles when long-distance recognition is assumed, while maintaining low brightness.

[0013] The coating composition is a coating composition for a detection target in sensing using near-infrared light, and comprises a coating film-forming resin (A), a color pigment (B), and an aggregate (E), wherein the color pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is taken as the near-infrared reflectance, and the aggregate (E) comprises an aggregate (E1) having a near-infrared reflectance of 5% or more, and is used for a detection target in sensing using near-infrared light.

[0014] The paint composition of the present disclosure can realize a marking that exhibits high retroreflectivity (particularly retroreflectivity at high angles of incidence) even when formed on a road surface, without being mistaken for a white line. Although the present disclosure should not be interpreted as being limited to a particular theory, the reason why the paint composition of the present disclosure can achieve such an effect is thought to be as follows. The paint composition of the present disclosure uses a pigment having a specific near-infrared reflectance as a coloring pigment, and therefore the resulting coating film can reflect near-infrared rays. Furthermore, the paint composition of the present disclosure further contains an aggregate having a specific near-infrared reflectance. Therefore, it is thought that even when a marking is formed on a road surface, it will be possible to exhibit retroreflectivity to near-infrared rays.

[0015] Specifically, the sensing may be a remote sensing technology, which may involve irradiating a detection target with near-infrared rays, detecting reflected light and / or scattered light from the irradiated position, and determining the distance and direction from the emitting position of the near-infrared rays to the irradiated position.

[0016] The wavelength of the near-infrared light used for the sensing is preferably 800 nm or more, more preferably 900 nm or more, and preferably 2,500 nm or less, more preferably 2,000 nm or less, and even more preferably 1,600 nm or less. The shorter the wavelength of near-infrared light, the more linear it is, and the longer the wavelength, the easier it is to eliminate the influence of sunlight. The wavelengths currently used in sensing are mainly 905 nm and / or 1,550 nm.

[0017] Hereinafter, the coating composition for detecting an object to be sensed using near-infrared light may be simply referred to as the "coating composition."

[0018] [Film-forming resin (A)] The film-forming resin (A) is a resin capable of forming a coating film, and resins commonly used in the coatings field can be used. Examples of the film-forming resin (A) include thermosetting resins, room temperature curing resins, and photocuring resins such as acrylic resins, polyester resins, polyurethane resins, alkyd resins, polyether resins, fluororesins, epoxy resins, silicone resins, and urea resins, and it is preferable to include at least one selected from acrylic resins, polyester resins, polyurethane resins, and urea resins. The film-forming resin (A) may form a coating film by itself, or may form a coating film by the action of a crosslinking agent (C) described below. The film-forming resin (A) may be used alone, or two or more types may be used in combination.

[0019] The acrylic resin represents a polymer having units derived from a monomer having a (meth)acryloyl group, and can be prepared by polymerizing a monomer mixture containing the monomer having a (meth)acryloyl group. The monomer mixture may further contain a monomer having an ethylenically unsaturated bond other than the monomer having a (meth)acryloyl group. In this specification, (meth)acrylic acid represents acrylic acid and methacrylic acid.

[0020] Examples of the monomer having a (meth)acryloyl group include (meth)acrylic acid; (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 1 to 20 carbon atoms; (meth)acrylic monomers having a hydroxy group such as hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and N-methylol (meth)acrylamide; lactone adducts of the above-mentioned (meth)acrylic monomers having a hydroxy group; and (meth)acrylonitrile.

[0021] Examples of the monomer having an ethylenically unsaturated group include, in addition to the monomer having a (meth)acryloyl group, monomers having a carboxy group such as crotonic acid, itaconic acid, and fumaric acid; anhydrides of the monomers having a carboxy group; and vinyl monomers such as styrene.

[0022] The polyester resin refers to a polymer having a plurality of ester bonds in the main chain, and can be obtained as a reaction product of a polyol and a polycarboxylic acid; an addition polymerization product of a cyclic ester; a reaction product of the reaction product of the polyol and polycarboxylic acid with a cyclic ester; etc.

[0023] The polyol is a compound having two or more hydroxy groups in one molecule, and examples thereof include aliphatic polyols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-pentanediol, neopentyl glycol, and 1,5-hexanediol; alicyclic polyols such as hydrogenated bisphenol A and 1,4-cyclohexanedimethanol; aromatic polyols such as bisphenol A and hydroxyalkylated bisphenol A; tri- or higher functional polyols such as glycerin, mannitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, and dipentaerythritol; sugar alcohols such as sorbitol; tris(hydroxyethyl)isocyanate; and N,N-bis(2-hydroxyethyl)dimethylhydantoin.

[0024] The number of hydroxy groups contained in the polyol is preferably 2 or more, or may be 3 or more, and is preferably 6 or less, more preferably 4 or less, per molecule.

[0025] The polyols may be used alone or in combination of two or more.

[0026] The polycarboxylic acid refers to a compound having two or more carboxy groups in one molecule. Examples of the polycarboxylic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclohexane-1,4-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, and methyl-5-norbornene-2,3-dicarboxylic acid; aliphatic polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, adipic acid, arachidic acid, sebacic acid, succinic acid, and dodecenylsuccinic acid; hydroxy acids of lactose; anhydrides of the aromatic polycarboxylic acids, alicyclic polycarboxylic acids, and aliphatic polycarboxylic acids; and the like. The polycarboxylic acids may be used alone or in combination of two or more.

[0027] Examples of the cyclic ester include ε-caprolactone.

[0028] The polyester resin also includes modified products of the polyester resins described above. The resin can be modified by reacting a modifying agent with the end of the main chain constituting the resin. Examples of the modifying agent include compounds having a reactive group such as an isocyanate group, a hydroxy group, or a carboxy group, or a silicone skeleton. Examples of the modified polyester resin include urethane-modified polyester resins, epoxy-modified polyester resins, acrylic-modified polyester resins, and silicone-modified polyester resins.

[0029] Examples of the urethane resin include a reaction product of a polyol and a polyisocyanate; a reaction product of the reaction product with a chain extender that is used as needed; and the like.

[0030] The polyol means a compound having two or more hydroxy groups in one molecule. Examples of the polyol include aliphatic polyols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-pentanediol, neopentyl glycol, 1,5-hexanediol, and 1,6-hexanediol; alicyclic polyols such as hydrogenated bisphenol A and 1,4-cyclohexanedimethanol; aromatic polyols such as bisphenol A and hydroxyalkylated bisphenol A (particularly, bisphenol hydroxypropyl ether); tri- or higher functional polyols such as glycerin, mannitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, and dipentaerythritol; and high molecular weight polyols (for example, polyols having a weight average molecular weight of 800 or more) such as polyether polyols, acrylic polyols, polyurethane polyols, polyester polyols, and polyesteramide polyols. The polyols may be used alone or in combination of two or more.

[0031] The number of hydroxy groups contained in the polyol is 2 or more, and may be 3 or more, but is preferably 6 or less, and more preferably 4 or less.

[0032] The polyisocyanate refers to a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, and hexamethylene diisocyanate; alicyclic polyisocyanates such as 1,3-cyclopentane diisocyanate, 1,4-dicyclohexylmethane diisocyanate, 1,2-cyclohexane diisocyanate, isophorone diisocyanate, norbornane diisocyanate methyl, and hydrogenated xylylene diisocyanate; Examples of the polyisocyanate include aromatic polyisocyanates such as 4-tolylene diisocyanate, 1,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, metaxylylene diisocyanate, naphthylene diisocyanate, and 3,3'-dimethyl-4,4'-biphenylene diisocyanate; and polymers such as biuret, isocyanurate, urethidine, and allophanate derivatives of the aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. One type of polyisocyanate may be used, or two or more types may be used in combination.

[0033] The chain extender refers to a compound having one or more active hydrogen atoms in one molecule, and may be water or an amine compound. Examples of the amine compound include aliphatic polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, and tetraethylenepentamine; aromatic polyamines such as tolylenediamine, xylylenediamine, and diaminodiphenylmethane; alicyclic polyamines such as diaminocyclohexylmethane, piperazine, 2,5-dimethylpiperazine, and isophoronediamine; hydrazine compounds such as hydrazine, succinic acid dihydrazide, adipic acid dihydrazide, and phthalic acid dihydrazide; and alkanolamines such as hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl)amino]ethanol, and 3-aminopropanediol.

[0034] In one embodiment, the urethane resin may be a polyester-based urethane resin, a polyether-based urethane resin, or a polycarbonate-based urethane resin.

[0035] Examples of the epoxy resin include epoxy resins having two or more epoxy groups in one molecule, such as glycidyl ester resins, glycidyl ether resins such as condensation products of bisphenol A and epichlorohydrin, and condensation products of bisphenol F and epichlorohydrin, as well as alicyclic epoxy resins, linear aliphatic epoxy resins, bromine-containing epoxy resins, phenol novolac epoxy resins, and cresol novolac epoxy resins.

[0036] Examples of the urea resin include a reaction product of a polyamine compound and a polyisocyanate compound. The polyamine compound and the polyisocyanate compound may be separately blended to form a two-component coating composition. The polyamine compound is a compound having two or more amino groups. The polyamine compound includes at least one selected from an aliphatic polyamine compound, an alicyclic polyamine compound, and an aromatic polyamine compound, and preferably includes at least one selected from an aliphatic polyamine compound and an alicyclic polyamine compound.

[0037] The amino group is preferably a primary or secondary amino group. In one embodiment, the amino group may be present in the molecular chain of the polyamine compound or at the molecular terminal. The polyamine compound may be, for example, a polyamine compound represented by the formula: R １２ HN-R １１ -NHR １２ (In the formula, R １ is a divalent C １－３０ represents a hydrocarbon group, and R １１ -CH contained in ２ - represents -O-, -CO- or -NR １２ - may be substituted, and R １２ is a monovalent C １－３０ represents a hydrocarbon group or a hydrogen atom. １－３０ The hydrocarbon group includes C １－３０ Aliphatic hydrocarbon group, C３－３０ Alicyclic hydrocarbon group and C ６－３０ Examples include aromatic hydrocarbon groups.

[0038] The aliphatic polyamine compound refers to a polyamine compound that does not have a ring structure in its molecular structure, and examples of such aliphatic polyamine compounds include alkylene polyamine compounds, polyalkylene polyamine compounds, and other aliphatic polyamine compounds.

[0039] Examples of alkylene polyamine compounds include methylene diamine, ethylene diamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane. Examples of polyalkylene polyamine compounds include diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, and hexamethylene tetramine. Other aliphatic polyamine compounds include tetrakis(2-aminoethylaminomethyl)methane, 1,3-bis(2'-aminoethylamino)propane, triethylene-bis(trimethylene)hexamine, bis(3-aminoethyl)amine, bishexamethylenetriamine, and aspartic acid ester amines represented by the following formula (11):

[0040] The alicyclic polyamine compound means a polyamine compound having an alicyclic structure in its molecular structure.

[0041] Examples of the alicyclic polyamine compound include 1,4-cyclohexanediamine, 4,4'-methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane (e.g., norbornadiamine), bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane (e.g., 4,4'-diaminodicyclohexylmethane), isophoronediamine, menthenediamine (MDA), 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2''-aminoethylamino)ethyl]piperazine, 1,11-diazacycloeicosane, and 1,15-diazacyclooctacosane.

[0042] The aromatic polyamine compound means a polyamine compound having an aromatic ring in the molecular structure. Examples of aromatic polyamine compounds include bis(cyanoethyl)diethylenetriamine, o-xylylenediamine, m-xylylenediamine (MXDA), p-xylylenediamine, phenylenediamine, naphthylenediamine, diaminodiphenylmethane, diaminodiethylphenylmethane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,4'-diaminobiphenyl, 2,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, bis(aminomethyl)naphthalene, bis(aminoethyl)naphthalene, and polytetramethylene oxide-di-p-aminobenzoate.

[0043] In one embodiment, the polyamine compound may include an aspartic acid ester amine represented by the following formula (I):

[0044] [In formula (I), R １ is a divalent C １－８０R represents one selected from hydrocarbon groups; ２ are, independently of each other, C １－２０ represents a hydrocarbon group.]

[0045] The polyamine compound may be used alone or in combination of two or more kinds.

[0046] The polyisocyanate refers to a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, and hexamethylene diisocyanate; alicyclic polyisocyanates such as 1,3-cyclopentane diisocyanate, 1,4-dicyclohexylmethane diisocyanate, 1,2-cyclohexane diisocyanate, isophorone diisocyanate, norbornane diisocyanate methyl, and hydrogenated xylylene diisocyanate; Examples of the polyisocyanate include aromatic polyisocyanates such as 4-tolylene diisocyanate, 1,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, metaxylylene diisocyanate, naphthylene diisocyanate, and 3,3'-dimethyl-4,4'-biphenylene diisocyanate; and polymers such as biuret, isocyanurate, urethidine, and allophanate derivatives of the aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. One type of polyisocyanate may be used, or two or more types may be used in combination.

[0047] The equivalent ratio of the isocyanate group contained in the polyisocyanate compound to the total amino group contained in the polyamine compound (hereinafter referred to as "NCO / NH ２ ") is preferably 0.5 to 2.0, more preferably 0.8 to 1.2. The amino group used in calculating the above equivalent ratio refers to the amino group that participates in the reaction with the polyisocyanate (for example, the amino group present at the molecular terminal). Having the equivalent ratio within the above range has the advantage of improving the water resistance, etc. of the coating film that is formed.

[0048] The film-forming resin (A) may have a hydrophilic group such as an anionic group, a cationic group, or a nonionic group. Examples of the anionic group include a carboxy group and a sulfonic acid group, and examples of the cationic group include an amino group and a quaternary ammonium group. Examples of the nonionic group include a polyoxyalkylene unit. The hydrophilic group can be introduced by using a compound having a hydrophilic group as a raw material for the film-forming resin (A), for example.

[0049] When the film-forming resin (A) has an anionic group, the coating composition may contain a basic compound capable of neutralizing the anionic group, and when the film-forming resin (A) has a cationic group, the coating composition may contain an acidic compound capable of neutralizing the cationic group.

[0050] When the film-forming resin (A) has an anionic group, the acid value of the film-forming resin (A) is preferably 5 mgKOH / g or more and 50 mgKOH / g or less, more preferably 5 mgKOH / g or more and 30 mgKOH / g or less.

[0051] When the film-forming resin (A) has a cationic group, the amine value of the film-forming resin (A) is preferably from 5 mgKOH / g to 50 mgKOH / g, more preferably from 5 mgKOH / g to 30 mgKOH / g.

[0052] The film-forming resin (A) may contain hydroxy groups. When the film-forming resin (A) contains hydroxy groups, the hydroxyl value of the film-forming resin (A) is preferably from 5 mg KOH / g to 35 mg KOH / g, more preferably from 7 mg KOH / g to 30 mg KOH / g, and even more preferably from 10 mg KOH / g to 25 mg KOH / g.

[0053] The acid value and hydroxyl value are both based on solid content and can be measured in accordance with JIS K 0070: 1999. The amine value is based on solid content and can be measured in accordance with JIS K 7237.

[0054] The coating film-forming resin (A) may be a resin that can be dissolved in an organic solvent, as described below, or may be an aqueous resin. Examples of the aqueous resin include water-soluble resins that can be dissolved in an aqueous medium, and water-dispersible resins that can be dispersed in an aqueous medium, such as colloidal dispersion type and emulsion type (emulsion polymerization type, forced emulsification type).

[0055] The weight average molecular weight of the film-forming resin (A) may be, for example, 2,000 to 10,000,000, 10,000 to 2,000,000, or 50,000 to 2,000,000. In the case of the emulsion-type water-dispersible resin, the weight average molecular weight of the film-forming resin (A) may be, for example, 50,000 to 10,000,000, 100,000 to 2,000,000, or 150,000 to 500,000. In the case of the resin soluble in an aqueous medium or organic solvent, the weight average molecular weight may be, for example, 2,000 to 100,000, 10,000 to 80,000, or 50,000 to 80,000. In this specification, the weight average molecular weight is a value measured by gel permeation chromatography and converted into polystyrene equivalent.

[0056] The content of the film-forming resin (A) is preferably 15% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 85% by mass or less, and even more preferably 30% by mass or more and 75% by mass or less, based on 100% by mass of the solid content of the coating composition.

[0057] In this specification, the solid content of the coating composition means the portion of all the components of the coating composition excluding the solvent (D) described below.

[0058] The coating composition may also contain a thermoplastic resin in addition to the film-forming resin (A), as long as it does not affect the physical properties of the coating film formed. Examples of the thermoplastic resin include chlorinated olefin resins such as chlorinated polyethylene and chlorinated polypropylene; homopolymers or copolymers containing vinyl chloride, vinyl acetate, vinylidene chloride, or the like as monomer components; cellulose resins; acetal resins; alkyd resins; chlorinated rubber resins; modified polypropylene resins (such as acid anhydride-modified polypropylene resins); fluororesins (such as vinylidene fluoride resins, vinyl fluoride resins, copolymers of fluorinated olefins and vinyl ethers, and copolymers of fluorinated olefins and vinyl esters). One type of thermoplastic resin may be used, or two or more types may be used in combination. By using a thermoplastic resin in combination, it becomes easier to adjust the physical properties of the coating film formed according to the purpose.

[0059] [Coloring Pigment (B)] The coloring pigment (B) is a pigment having a color such as a chromatic color or an achromatic color, and includes a pigment (B1) capable of reflecting near-infrared rays. The near-infrared reflectance of the pigment (B1) is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more, and is also acceptable to be 100% or less, 90% or less, or 80% or less. By including the pigment (B1), when near-infrared rays are irradiated, the irradiated light is reflected and / or scattered with high intensity, which can contribute to improving the detection accuracy in LiDAR technology.

[0060] In this specification, the near-infrared reflectance refers to the arithmetic mean value of the spectral reflectance measured in the wavelength range of 800 to 2,500 nm in accordance with JIS K 5602: 2008. The spectral reflectance can be measured using a spectrophotometer.

[0061] In this specification, the near-infrared reflectance of a pigment can be measured by forming a coating film containing the pigment and measuring the reflectance of the coating film. Specifically, the pigment, resin, and solvent described in Measurement Example 1 of Near-Infrared Reflectance and Spectral Reflectance of Pigments below are mixed so that the pigment mass concentration (also referred to as PWC) shown in the following formula is 3 to 50% by mass, and the mixture is dispersed using a disperser at a rotation speed of 1,800 rpm for 60 minutes to form a dispersion. The dispersion is then applied to a black-and-white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) as a base using an 8-mil doctor blade to a thickness of approximately 50 μm after drying, and dried at 60°C for 20 minutes to form a dried coating film. In accordance with JIS K 5602:2008, the spectral reflectance of the white-based portion of the dried coating film is measured in the wavelength range of 800 to 2,500 nm using a spectrophotometer, and the arithmetic average value is taken as the near-infrared reflectance of the pigment. The spectral reflectance at wavelengths of 905 nm and 1,550 nm, which will be described later, can also be measured in accordance with the method for measuring spectral reflectance described above. For example, a spectrophotometer (Shimadzu Corporation, SHIMADZU-UV3600, etc.) can be used for the measurement. Pigment mass concentration (PWC: mass %) = (pigment solid content) / (pigment solid content + resin solid content) × 100

[0062] In this specification, the solids content of the resin means the total solids content of the film-forming resin (A) and the crosslinking agent (C) used as needed, which will be described later, and can be determined by measuring the heating residue (mass of the residue after heating at 105°C for 60 minutes) in accordance with JIS K 5601-1-2 (2008).

[0063] In addition, when measuring near-infrared reflectance and spectral reflectance, the pigment mass concentration of each pigment is set to a concentration at which, when a dry coating film is formed on the black-and-white hiding power test paper, the white and black underlying layers are not visible. In this specification, the pigment mass concentrations of each pigment are set to 25% by mass for organic red pigments, 30% by mass for inorganic red pigments, 25% by mass for organic yellow pigments, 30% by mass for inorganic yellow pigments, 20% by mass for blue pigments, 45% by mass for white pigments, 3% by mass for organic black pigments, and 50% by mass for inorganic black pigments.

[0064] The pigment (B1) preferably includes a pigment selected from the group consisting of chromatic pigments and achromatic pigments. The chromatic pigments include any pigments with a color saturation greater than 0, such as reddish pigments, greenish pigments, blueish pigments, and yellowish pigments. The pigment (B1) preferably includes one or more pigments selected from the group consisting of reddish pigments, blueish pigments, and yellowish pigments, and more preferably includes one or more pigments selected from the group consisting of reddish pigments, blueish pigments, and yellowish pigments.

[0065] Furthermore, organic pigments and / or inorganic pigments can be used as the pigment (B1). The organic pigments tend to have high saturation and high near-infrared reflectance, while the inorganic pigments tend to have high weather resistance. The content of the organic pigment in a total of 100% by mass of the pigment (B1) may be 0% by mass or more and 100% by mass or less, 0.3% by mass or more and 70% by mass or less, 0.5% by mass or more and 15% by mass or less, or 0.5% by mass or more and 8% by mass or less. The content of the inorganic pigment in a total of 100% by mass of the pigment (B1) may be 0% by mass or more and 100% by mass or less, 5% by mass or more and 99% by mass or less, 10% by mass or more and 50% by mass or less, or 10% by mass or more and 20% by mass or less.

[0066] The near-infrared reflectance of the red pigment as pigment (B1) is, for example, preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more, and is acceptable to be, for example, 80% or less, or even 70% or less. The spectral reflectance of the red pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 20% or more, more preferably 25% or more, even more preferably 30% or more, and even more preferably 35% or more, and is acceptable to be, for example, 90% or less, or even 85% or less.

[0067] The red pigment may be an organic pigment and / or an inorganic pigment, and the content of the organic pigment in the red pigment may be 0% by mass, 1% by mass or more and 100% by mass or less, or 20% by mass or more and 50% by mass or less.

[0068] The near-infrared reflectance of the organic red pigment is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more. For example, it is acceptable for the reflectance to be 80% or less, or even 70% or less.

[0069] The spectral reflectance of the organic red pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 40% or more, more preferably 50% or more, even more preferably 55% or more, and still more preferably 60% or more. For example, it is acceptable for the spectral reflectance to be 90% or less, or even 85% or less.

[0070] The near-infrared reflectance of the inorganic red pigment is preferably 40% or more, more preferably 45% or more, and is acceptable to be, for example, 80% or less, and even 70% or less.

[0071] The spectral reflectance of the inorganic red pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 20% or more, more preferably 30% or more, and is acceptable to be, for example, 90% or less, and further 85% or less.

[0072] Examples of red pigments as the pigment (B1) include organic red pigments such as Fastogen Super Magenta RH, Fastogen Red 7100Y, Fastogen Super Red 500RG, Fastogen Super Red ATY, Fastogen Super Blue Violet RVS, Rubicron Red 400RG, and Rubicron Red 500RG (all manufactured by DIC Corporation), and CINILEX DPP RED SR1C (manufactured by CINIC Chemicals), and inorganic red pigments such as Todacolor 120ED (manufactured by Toda Kogyo Co., Ltd.) and BAYFERROX 130M (manufactured by Lanxess AG).

[0073] The near-infrared reflectance of the blue pigment as pigment (B1) is preferably 40% or more, more preferably 45% or more, and is acceptable to be, for example, 80% or less, or even 70% or less.

[0074] The spectral reflectance of the blue pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 30% or more, more preferably 35% or more, and is acceptable to be, for example, 90% or less, and even 85% or less.

[0075] Examples of the blue pigment include Dipyroxide Color Blue 9453 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), FastogenBlue 9453, Fastogen Blue RS, Fastogen Blue 5380, Fastogen Super Blue 6070S (all manufactured by DIC Corporation), Cyanine Blue 5240KB, Cyanine Blue 5050 (all manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), HELIOGEN BLUE L7460 (manufactured by BASF), Dipyroxide Color Green 9310 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), FastogenGreen2 YK, FastogenGreen MY (all manufactured by DIC Corporation), and Lionol Green 6YKP-N (manufactured by Toyocolor Co., Ltd.).

[0076] The near-infrared reflectance of the yellow pigment is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more. For example, it is acceptable for the reflectance to be 90% or less, or even 85% or less.

[0077] The spectral reflectance of the yellow pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 15% or more, more preferably 20% or more, even more preferably 25% or more, and still more preferably 30% or more. For example, it is acceptable for the spectral reflectance to be 95% or less, or even 90% or less.

[0078] The yellow pigment may be an organic pigment and / or an inorganic pigment. The content of the organic pigment in the yellow pigment may be 0% by mass, 1% by mass or more, or 10% by mass or more. The content may be 50% by mass or less, with the upper limit being 100% by mass.

[0079] The near-infrared reflectance of the organic yellow pigment is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more. For example, it is acceptable for the reflectance to be 90% or less, or even 85% or less.

[0080] The spectral reflectance of the organic yellow pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more. For example, it is acceptable for the spectral reflectance to be 95% or less, or even 90% or less.

[0081] The near-infrared reflectance of the inorganic yellow pigment is preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, and even more preferably 55% or more. For example, it is acceptable for the reflectance to be 90% or less, or even 85% or less.

[0082] The spectral reflectance of the inorganic yellow pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 20% or more, more preferably 25% or more, and is acceptable to be, for example, 90% or less, or even 85% or less.

[0083] Examples of the yellow pigment include organic yellow pigments such as Symuler Fast Yellow 4192 (manufactured by DIC Corporation) and HOSTAPERM YELLOW H3G (manufactured by Clariant Japan K.K.), and inorganic yellow pigments such as Sico Pearl Yellow L-1110 and Sico Pearl Yellow L-1100 (both manufactured by BASF), and TAROX Synthetic Iron Oxide YM1100 (manufactured by Titanium Industries Co., Ltd.).

[0084] The chromatic pigment as the pigment (B1) preferably includes a red pigment, a blue pigment, and a yellow pigment, such as a mixture of Symuler Fast Yellow 4192 (manufactured by DIC Corporation) as a yellow pigment, Fastogen Red 7100Y (manufactured by DIC Corporation) as a red pigment, and Lionol Blue FG7980 (manufactured by Toyocolor Co., Ltd.) as a blue pigment.

[0085] The total content of the red pigment, blue pigment, and yellow pigment in the chromatic pigment is, for example, 20% by mass or more, preferably 30% by mass or more, with the upper limit being 100% by mass.

[0086] The content of the chromatic pigment in the pigment (B1) may be, for example, 0% by mass or more, 1% by mass or more, or 5% by mass or more, and may be, for example, 100% by mass or less, 70% by mass or less, 50% by mass or less, 25% by mass or less, 20% by mass or less, or 18% by mass or less.

[0087] The achromatic pigment includes any pigment having a saturation of 0. Examples of the achromatic pigment include white pigments, gray pigments, and black pigments, and include white pigments and black pigments.

[0088] The near-infrared reflectance of the white pigment as the pigment (B1) is preferably 60% or more, more preferably 65% ​​or more, even more preferably 70% or more, and still more preferably 75% by mass or more. For example, it is acceptable for the reflectance to be 99% or less, or even 90% or less.

[0089] Examples of the white pigment include titanium oxides such as TIPAQUE CR-97 and TIPAQUE CR-95 (both manufactured by Ishihara Sangyo Kaisha), and Tipure R-902 (manufactured by DuPont).

[0090] The spectral reflectance of the white pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 60% or more, more preferably 65% ​​or more, even more preferably 70% or more, and still more preferably 75% by mass or more. For example, it is acceptable for the spectral reflectance to be 99% or less, or even 90% or less.

[0091] The content of the white pigment in the pigment (B1) may be, for example, 0% by mass or more, 1% by mass or more, or 3% by mass or more, or 100% by mass or less, 99% by mass or less, or 90% by mass or less, for example, 60% by mass or less, 55% by mass or less, or 50% by mass or less.

[0092] The near-infrared reflectance of the black pigment as the pigment (B1) is preferably 5% or more, more preferably 8% or more, even more preferably 10% or more, and still more preferably 15% or more. For example, it is acceptable for the reflectance to be 90% or less, or even 85% or less.

[0093] The spectral reflectance of the black pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 5% or more, more preferably 8% or more, even more preferably 10% or more, and even more preferably 15% or more. For example, it is acceptable for the spectral reflectance to be 90% or less, or even 85% or less.

[0094] The black pigment may be an organic pigment and / or an inorganic pigment, and the content of the organic pigment in the black pigment may be 0% by mass, 1% by mass or more, 20% by mass or more, or 50% by mass or less, with the upper limit being 100% by mass.

[0095] The near-infrared reflectance of the organic black pigment is preferably 20% or more, more preferably 30% or more, even more preferably 35% or more, and still more preferably 40% or more. For example, it is acceptable for the reflectance to be 80% or less, or even 70% or less.

[0096] The spectral reflectance of the organic black pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 40% or more, more preferably 50% or more, even more preferably 55% or more, and still more preferably 60% or more. For example, it is acceptable for the spectral reflectance to be 90% or less, or even 85% or less.

[0097] The near-infrared reflectance of the inorganic black pigment is preferably 30% or more, more preferably 40% or more, and is acceptable to be, for example, 80% or less, and even 70% or less.

[0098] The spectral reflectance of the inorganic black pigment at wavelengths of 905 nm and / or 1,550 nm is preferably 5% or more, more preferably 10% or more, and is acceptable to be, for example, 85% or less, or even 80% or less.

[0099] Examples of the black pigment include inorganic black pigments such as Dipyroxide Color Black 9590, Dipyroxide Color Brown 9290, and Dipyroxide Color Brown 9211 (all manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Black 411 (manufactured by The Shepherd Color Company), and Black 6350 (manufactured by Asahi Kasei Kogyo Co., Ltd.), and organic black pigments such as Chromofine Black A-1103 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Fastogen Super Black MX (manufactured by DIC Corporation), Paliogen Black S0084, and Paliotol Black L0080 (all manufactured by BASF), and Hoster Palm Brown HFR-01 (manufactured by Clariant Japan KK).

[0100] The content of the black pigment in the pigment (B1) may be 0% by mass or more, 1% by mass or more, or 5% by mass or more, and may be, for example, 50% by mass or less, 45% by mass or less, or 40% by mass or less.

[0101] The total content of the white pigment and the black pigment in the achromatic pigment is, for example, 50% by mass or more, preferably 60% by mass or more, with the upper limit being 100% by mass.

[0102] The content of the achromatic pigment may be 0 parts by mass or more, 10 parts by mass or more, or 50 parts by mass or more relative to 100 parts by mass of the chromatic pigment, and may be, for example, 20,000 parts by mass or less, 10,000 parts by mass or less, 5,000 parts by mass or less, or 2,500 parts by mass or less.

[0103] The pigment (B1) may be used alone or in combination of two or more kinds.

[0104] In one embodiment, the pigment (B1) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 5% or more. By including such a pigment in the pigment (B1), it is possible to improve the near-infrared detection accuracy of the resulting coating film in LiDAR technology, and preferably to improve the near-infrared detection accuracy of the LiDAR technology while maintaining low brightness.

[0105] The pigment (B1) preferably includes at least one selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a blue pigment having a near-infrared reflectance of 50% or more, a red pigment having a near-infrared reflectance of 50% or more, a yellow pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more; a white pigment having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1,550 nm, a blue pigment having a spectral reflectance of 40% or more at a wavelength of 905 nm and / or 1,550 nm, a black pigment having a spectral reflectance of 50% or more at a wavelength of 905 nm and / or 1,550 nm, a It is more preferable that the pigment contains at least one pigment selected from the group consisting of an organic red pigment having a spectral reflectance of 20% or more at wavelengths of 905 nm and / or 1,550 nm, an organic yellow pigment having a spectral reflectance of 60% or more at wavelengths of 905 nm and / or 1,550 nm, an inorganic yellow pigment having a spectral reflectance of 20% or more at wavelengths of 905 nm and / or 1,550 nm, an organic black pigment having a spectral reflectance of 50% or more at wavelengths of 905 nm and / or 1,550 nm, and an inorganic black pigment having a spectral reflectance of 15% or more at wavelengths of 905 nm and / or 1,550 nm.

[0106] The total content of the pigment (B1) in the color pigment (B) may be 20% by mass or more, 30% by mass or more, or 50% by mass or more, and may be, for example, 100% by mass or less, 98% by mass or less, or 95% by mass or less.

[0107] The color pigment (B) may contain a color pigment (b) other than the pigment (B1) to the extent that the near-infrared reflectance and spectral reflectance of the coating film obtained from the coating composition are not affected. The color pigment (b) may be any compound classified as a pigment in the Color Index other than the pigment (B1). Examples of the color pigment (b) include organic black pigments, such as carbon black. The content (pigment mass concentration) of the color pigment (b) in the color pigment (B) may be 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less.

[0108] The average primary particle diameter (D50) of the color pigment (B) can be preferably 1 nm or more and 500 nm or less, more preferably 5 nm or more and 300 nm or less. The average primary particle diameter (D50) of the color pigment (B) can be measured using a laser Doppler particle size analyzer (e.g., Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.)).

[0109] The content of the organic pigment may be 0% by mass or more and 100% by mass or less, 0.3% by mass or more and 70% by mass or less, 0.5% by mass or more and 10% by mass or less, or 3% by mass or more and 8% by mass or less, relative to 100% by mass of the total pigment (B). The content of the inorganic pigment may be 0% by mass or more and 100% by mass or less, 5% by mass or more and 99% by mass or less, 10% by mass or more and 50% by mass or less, or 10% by mass or more and 20% by mass or less, relative to 100% by mass of the total pigment (B).

[0110] The content of the pigment (B) (pigment mass concentration) is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more, relative to 100% by mass of the total solid content of the coating film-forming resin (A), the pigment (B), and the crosslinking agent (C) used as needed, which is described below, and is preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less.

[0111] The content (pigment mass concentration) of the pigment (B1) is preferably 3 mass% or more, more preferably 8 mass% or more, and even more preferably 10 mass% or more, relative to 100 mass% of the total solids content of the coating film-forming resin (A), the pigment (B), and the crosslinking agent (C) used as needed, which will be described later, and is preferably 55 mass% or less, more preferably 50 mass% or less, and even more preferably 45 mass% or less.

[0112] The lightness (L* value) of the coating film obtained by the coating composition is preferably 80 or less, and may be, for example, 5 or more. It may also be, for example, 70 or less, or 15 or more. By using the coating composition of the present invention, visibility in LiDAR technology can be maintained even when the lightness (L* value) of the coating film is low. Note that the lightness (L* value) of the coating film may vary depending on the thickness (film thickness) of the coating film.

[0113] In this specification, the brightness of a coating film can be measured in the same manner as the brightness of a coating film containing the pigment. Specifically, the pigment, resin, and solvent described in Measurement Example 1 of Pigment Near-Infrared Reflectance and Spectral Reflectance below are mixed to a pigment mass concentration of 3 to 50% by mass, and the mixture is dispersed using a disperser at a rotation speed of 1,800 rpm for 60 minutes to form a dispersion. The dispersion is then coated using a black-and-white opacity test paper (manufactured by Nippon Test Panel Co., Ltd.) as a base to a thickness of approximately 100 μm after drying, and dried at 60°C for 20 minutes to form a dried coating film. The brightness of the white-based portion of the resulting dried coating film is measured in accordance with JIS K 5600-4-4-3.2 and JIS K 5600-4-5, and this brightness can be determined. The brightness can be measured, for example, using a color difference meter CM-600d (manufactured by Konica Minolta, Inc.).

[0114] The desired brightness of the coating film is expressed as L* ０ When the above L* ０ The relationship between the range of the pigment mass concentration of each pigment and L* is expressed by the following formula: That is, the pigment mass concentration of each pigment may be in a range that satisfies the following formula: ０ L* can take the value in the range described above as the lightness of the coating film. ０= 0.7(W) - 0.6(IR) - 5.5(OR) + 0.4(IY) - 3.2(OY) - 5.7(OB) - 0.2(IBL) - 0.3(OBL) + 48.5 ... Formula (1) Here, (W) is the pigment mass concentration (mass%) of the white pigment, (IR) is the pigment mass concentration (mass%) of the inorganic red pigment, (OR) is the pigment mass concentration (mass%) of the organic red pigment, (IY) is the pigment mass concentration (mass%) of the inorganic yellow pigment, (OY) is the pigment mass concentration (mass%) of the organic yellow pigment, (OB) is the pigment mass concentration (mass%) of the blue pigment, (IBL) is the pigment mass concentration (mass%) of the inorganic black pigment, and (OBL) is the pigment mass concentration (mass%) of the organic black pigment.

[0115] The near-infrared reflectance of the desired coating film is X ０ (%), the X ０ The relationship between the mass concentration of each pigment and the mass ratio of each pigment is expressed by the following formula: In other words, the mass concentration of each pigment may be in a range that satisfies the following formula: ０ (%) can take the value in the range described above as the near-infrared reflectance of the coating film. ０ =0.5(W)-1.4(IR)+0.1(OR)-0.6(IY)-1.8(OY)-3.1(OB)-0.2(IBL)-13.2(OBL)+61.0...Formula (2)

[0116] The spectral reflectance of the target coating film at a wavelength of 905 nm is defined as Y ０ When Y is expressed as a percentage, the relationship between the pigment mass concentration of each pigment and the pigment mass concentration of each pigment is expressed by the following formula: In other words, the pigment mass concentration of each pigment may be in a range that satisfies the following formula. ０ Y (%) can take the value in the range described above as the spectral reflectance of the coating film at a wavelength of 905 nm. ０ =0.6(W)-2.9(IR)+3.5(OR)-1.2(IY)-0.9(OY)-3.0(OB)-0.8(IBL)-1.2(OBL)+68.0...Formula (3)

[0117] The spectral reflectance of the target coating film at a wavelength of 1,550 nm is Z ０ (%), the Z ０The relationship between Z (%) and the pigment mass concentration of each pigment is expressed by the following formula: In other words, the pigment mass concentration of each pigment may be in a range that satisfies the following formula: ０ Z (%) can take the value in the range described above as the spectral reflectance of the coating film at a wavelength of 905 nm. ０ =0.3(W)-0.2(IR)-2.4(OR)-0.2(IY)-1.4(OY)-2.0(OB)+0.1(IBL)-8.5(OBL)+68.0...Formula (4)

[0118] The lightness of the coating film may be 80 or less. Various combinations of pigment mass concentrations are calculated using formula (1). Among these combinations, formulas (2) to (4) can be used to calculate combinations of pigment concentrations that achieve desired values ​​or higher (e.g., 15% or higher) for the near-infrared reflectance, the spectral reflectance at a wavelength of 905 nm, and the spectral reflectance at a wavelength of 1,550 nm.

[0119] [Crosslinking Agent (C)] In addition to the film-forming resin (A) and the pigment (B), the coating composition may contain a crosslinking agent (C). The crosslinking agent (C) is a compound capable of forming a crosslinked structure in the film-forming resin (A) by forming a chemical bond and / or a physical bond. Examples of the crosslinking agent (C) include a compound having two or more groups containing active hydrogen atoms, such as hydroxy groups, carboxy groups, or amino groups, per molecule; or a compound having two or more groups reactive with the groups containing active hydrogen atoms per molecule. When the film-forming resin (A) contains a group containing an active hydrogen atom or a group reactive with the group containing an active hydrogen atom, it can react with the crosslinking agent (C) to form a crosslinked structure in the film-forming resin (A).

[0120] Examples of the crosslinking agent (C) include polyisocyanate compounds, blocked polyisocyanate compounds, amino resins, phenolic resins, polycarboxylic acids, etc. These may be used alone or in combination of two or more.

[0121] The polyisocyanate compound refers to a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and mixtures thereof, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, and mixtures thereof, naphthylene-1,5-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, and xylylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylylene diisocyanate; and aliphatic polyisocyanates such as hexamethylene diisocyanate.

[0122] The blocked polyisocyanate compound (hereinafter, sometimes referred to as "BI") means a compound in which the isocyanate group of the isocyanate compound is blocked with a blocking agent.

[0123] The blocking agent may be any compound having an active hydrogen-containing compound, and examples thereof include phenolic compounds such as phenol, cresol, and xylenol; lactam compounds such as ε-caprolactam, δ-valerolactam, and γ-butyrolactam; aliphatic alcohol compounds such as methanol, ethanol, and n-, i-, or t-butyl alcohol; glycol ether compounds such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, and propylene glycol monomethyl ether; aromatic alcohol compounds such as benzyl alcohol; oxime compounds such as formamidoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexane oxime; and active methylene compounds such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, and acetylacetone. By mixing the polyisocyanate compound with the blocking agent, free isocyanate groups of the polyisocyanate compound can be blocked.

[0124] The amino resin refers to a resin obtained by addition polymerization of an aldehyde with a compound having an amino group. The amino resin is preferred because it has excellent crosslinking reactivity with the coating film-forming resin (A), especially in the absence of a catalyst.

[0125] Examples of the amino resin include melamine resin and urea resin, with melamine resin being preferred.

[0126] The melamine resin is a thermosetting resin synthesized from melamine and aldehyde. The melamine resin has a triazine nucleus and three reactive functional groups (-NX) per triazine nucleus. １ X ２ The melamine resin has a reactive functional group of —N(CH ２ OR) ２ [R represents an alkyl group having 1 to 8 carbon atoms, the same applies hereinafter]; ２ OR) (CH ２ methylol group type containing -N(CH ２ imino group type containing -N(CH ２ OR) (CH ２ -OH) and -N(CH ２ OR)(H), or -N(CH ２ Four types of methylol / imino group type containing (OH)(H) are listed. As the melamine resin, one type may be used, or two or more types may be used in combination. As the crosslinking agent (C), the melamine resin and the polyisocyanate compound may be used in combination. Furthermore, a metal catalyst such as a tin compound or a titanium compound may be used as needed.

[0127] Examples of the phenol compound include glycidyl ether resins such as a condensation reaction product of bisphenol A and epichlorohydrin, and a condensation reaction product of bisphenol F and epichlorohydrin; alicyclic epoxy resins, linear aliphatic epoxy resins, bromine-containing epoxy resins, phenol novolac epoxy resins, and cresol novolac epoxy resins.

[0128] The polycarboxylic acid refers to a compound having two or more carboxy groups in one molecule. Examples of the polycarboxylic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclohexane-1,4-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, and methyl-5-norbornene-2,3-dicarboxylic acid; aliphatic polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, and dodecenylsuccinic acid; hydroxy acids of lactose; and anhydrides of the aromatic polycarboxylic acids, alicyclic polycarboxylic acids, and aliphatic polycarboxylic acids.

[0129] In one embodiment, the crosslinking agent (C) is preferably at least one selected from the group consisting of polyisocyanate compounds, blocked polyisocyanate compounds, and amino resins.

[0130] The content of the crosslinking agent (C) may be, for example, 3 parts by mass or more, 7 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more, per 100 parts by mass of the total of 100 parts by mass of the coating film-forming resin (A) and the crosslinking agent (C), and may be, for example, 50 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less.

[0131] The total content of the film-forming resin (A) and the crosslinking agent (C) is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, based on the solid content of the coating composition, and is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0132] [Solvent (D)] The coating composition may further contain a solvent (D). The solvent preferably contains an aqueous medium (D1) and / or an organic solvent (D2).

[0133] Examples of the aqueous medium (D1) include water, a hydrophilic solvent, and a mixture of water and a hydrophilic solvent.

[0134] Examples of the hydrophilic solvent include glycol solvents such as ethylene glycol, propylene glycol, butanediol, pentanediol, diethylene glycol, dipropylene glycol, and triethylene glycol; glycol ether solvents such as ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate; alcohol solvents such as methanol, ethanol, and isopropyl alcohol; ketone solvents such as acetone; and N-methyl-2-pyrrolidone. The use of such hydrophilic solvents has the advantage of improving the wettability of the resulting coating composition with the substrate.

[0135] Examples of the organic solvent (D2) include ether solvents such as dioxane and tetrahydrofuran; ester solvents such as 3-methoxybutyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbon solvents such as toluene, T-SOL 100, and T-SOL 150 (all manufactured by Exxon Chemical Co.); hydrocarbon solvents such as pentane, isopentane, hexane, isohexane, and cyclohexane; and mineral oils such as solvent naphtha and mineral spirits. These may be used alone or in combination of two or more.

[0136] The coating composition may be an aqueous coating composition containing an aqueous medium (D1) as the solvent (D), or a solvent-based coating composition containing an organic solvent (D2) as the solvent (D). When the coating composition is an aqueous coating composition, the content of the aqueous medium (D1) in the solvent (D) is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 100% by mass or less. When the coating composition is a solvent-based coating composition, the content of the organic solvent (D2) in the solvent (D) is preferably 50% by mass or more, more preferably 70% by mass or more, and preferably 100% by mass or less.

[0137] The content of the solvent (D) in the coating composition is preferably 0 mass% or more, more preferably 10 mass% or more, even more preferably 30 mass% or more, and is preferably 70 mass% or less, more preferably 60 mass% or less.

[0138] The coating composition may be a water-based coating, an organic solvent-based coating, or a solventless coating such as a powder coating.

[0139] [Aggregate (E)] The coating composition contains aggregate (E). In the present disclosure, aggregate (E) is an irregularly shaped granular material and contains aggregate (E1) having a near-infrared reflectance of 5% or more. However, aggregate (E) is different from pigment (B).

[0140] Examples of the material constituting the aggregate (E1) include SiO ２ , TiO ２ , Al ２ O ３ , Cr ２ O ３ , ZrO ２ , FeO, Fe ２ O ３ , CaP, CrO, Al ２ O ３ SiO ２ , 3Al ２ O ３ 2SiO ２ The fine particles may be particles of zirconia silicate, ceramic beads, or mixtures thereof. The fine particles may be particles, spheres, or hollow spheres.

[0141] The near-infrared reflectivity of the aggregate (E1) is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more, and may be, for example, 99% or less, or even 90% or less, so that near-infrared rays are reflected and scattered on the surface of the display, and good retroreflectivity can be obtained even at high incident angles.

[0142] The near-infrared reflectance of aggregate (E) can be measured by the following method. [Method for Measuring Near-Infrared Reflectance] The adhesive surface of a black adhesive sheet measuring 15 cm in length and 7 cm in width is covered with aggregate (E), the sheet is leaned against a wall, and any aggregate (E) not in contact with the adhesive surface is brushed off. This procedure is repeated until the black adhesive surface is no longer visible to the naked eye and no aggregate (E) naturally detaches from the leaning sheet. Next, the spectral reflectance of the adhesive surface covered with aggregate (E) is measured in the wavelength range of 800 to 2,500 nm using a spectrophotometer in accordance with JIS K 5602:2008, and the arithmetic average of the obtained spectral reflectances is used as the near-infrared reflectance of the aggregate (E). Spectral reflectance at wavelengths of 905 nm and 1,550 nm can also be measured in accordance with the method for measuring spectral reflectance described above. The measurement can be carried out using, for example, a spectrophotometer (Shimadzu Corporation, SHIMADZU-UV3600, etc.).

[0143] The spectral reflectance of the aggregate (E1) at wavelengths of 905 nm and / or 1,550 nm is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more. For example, it is acceptable for the spectral reflectance to be 99% or less, or even 90% or less.

[0144] The average particle size of the aggregate (E1) is preferably 50 μm or more, more preferably 50 μm or more and 3,000 μm or less, even more preferably 70 μm or more and 2,500 μm or less, still more preferably 100 μm or more and 2,000 μm or less, even more preferably 150 μm or more and 2,000 μm or less, and still more preferably 200 μm or more and 2,000 μm or less. The average particle size of the aggregate (E) means the volume average particle size (D50), and can be measured using a sieving method (for example, a JIS test sieve (manufactured by Iida Seisakusho)). As the sieve, for example, a sieve with an opening diameter of 106 μm or more and 3,360 μm or less can be used, and specifically, sieves with opening diameters of 150 μm, 180 μm, 212 μm, 250 μm, 300 μm, 425 μm, 500 μm, 710 μm, 1,000 μm, and 1,700 μm can be used.

[0145] In the present disclosure, the average particle size of the aggregate (E) means a weighted average of three or more sieves with different mesh sizes, the average particle size of the aggregate that passed through all sieves being half the mesh size of the sieve with the smallest mesh size, the average particle size of the aggregate (remaining portion) that did not pass through the sieve with the largest mesh size being the mesh size of the sieve with the largest mesh size, and the average particle size of the remainder on the other sieves being the average value of the mesh size of the sieve and the mesh size of a sieve that is one size smaller than the sieve, and the amount of the remainder on each sieve (sieve residue: mass %) is calculated.

[0146] Commercially available products may be used as the aggregate (E1), such as Cerasand HR-C, Cerasand HR-S, and Cerasand HR-B (manufactured by Bishu Kosan Co., Ltd.) and White Silica (manufactured by Yamamori Tsuchimoto Kogyosho Co., Ltd.).

[0147] The content of the aggregate (E1) contained in the aggregate (E) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on a total of 100% by mass of the aggregate (E), and is preferably 100% by mass or less.

[0148] The aggregate (E) may contain, in addition to the aggregate (E1), another aggregate (E2). Examples of the aggregate (E2) include aggregates having a near-infrared reflectance of less than 5%. Examples of materials constituting the aggregate (E2) include the same materials as those constituting the aggregate (E1).

[0149] The content of the aggregate (E) is preferably 5% by mass or more and 85% by mass or less, more preferably 10% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 60% by mass or less, based on 100% by mass of the total solid content of the film-forming resin (A), the pigment (B), the aggregate (E), and the optionally used crosslinking agent (C). In the present disclosure, the content of the aggregate (E) based on 100% by mass of the total solid content of the film-forming resin (A), the pigment (B), the aggregate (E), and the optionally used crosslinking agent (C) is also referred to as the mass concentration of the aggregate (E).

[0150] The coating composition may further contain other additives. Examples of the other additives include surface conditioners, extender pigments, colorants such as dyes, waxes, luster pigments, fillers (which may contain particulate fillers, etc., different from the aggregate (E)), ultraviolet absorbers (benzophenone-based ultraviolet absorbers, etc.), antioxidants (phenolic, sulfide, hindered amine antioxidants, etc.), plasticizers, coupling agents (silane-based, titanium, zirconium-based coupling agents, etc.), anti-sagging agents, thickeners, pigment dispersants, pigment wetting agents, leveling agents, color separation inhibitors, precipitation inhibitors, antifoaming agents, antifreeze agents, emulsifiers, preservatives, mildew inhibitors, antibacterial agents, stabilizers, etc. These additives may be used alone or in combination of two or more.

[0151] Examples of the luster pigment include mica, aluminum foil, tin foil, gold foil, silver foil, titanium gold foil, stainless steel foil, and metal foil such as nickel or copper foil.

[0152] The coating composition can be prepared by dissolving or dispersing the film-forming resin (A), the pigment (B), and the aggregate (E), as well as the optional crosslinker (C) and other additives, in the optional solvent (D). The order of mixing the various materials used is not particularly limited. For example, the pigment (B) and / or aggregate (E) may be premixed with a portion of the film-forming resin (A) to form a pigment paste, which may then be mixed with the remaining components and other optional components to produce the coating composition. The coating composition of the present specification can be prepared by mixing the components using a mixer, disperser, kneader, or the like, selected from a sand grinding mill, ball mill, blender, paint shaker, or disperser.

[0153] In the present disclosure, the technical scope of the paint composition also includes a paint film formed by preparing a preliminary paint composition using the film-forming resin (A) and pigment (B), as well as the crosslinking agent (C) and other additives used as needed, and then spraying aggregate (E) onto the paint film formed by applying the preliminary paint composition, or a paint film formed by spraying aggregate (E) onto the paint film and then applying the preliminary paint composition thereon.

[0154] A coating film formed from the coating composition is also included within the technical scope of the present disclosure.

[0155] The near-infrared reflectance of the coating film is preferably 15% or more, more preferably 30% or more, and even more preferably 35% or more, and is acceptable to be, for example, 99% or less, or even 90% or less.

[0156] The spectral reflectance of the coating film at wavelengths of 905 nm and / or 1,550 nm is preferably 20% or more, more preferably 30% or more, and even more preferably 35% or more. For example, it is acceptable for the reflectance to be 99% or less, or even 90% or less.

[0157] The near-infrared reflectance of the coating film, and the spectral reflectance at wavelengths of 950 nm and / or 1,550 nm, can be measured, for example, according to a method similar to the method described as the method for measuring the near-infrared reflectance of a coating film containing a pigment when measuring the near-infrared reflectance of a pigment.

[0158] The coating film for measuring the near-infrared reflectance can be formed, for example, by the following method: The coating composition is applied to a black-and-white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) as a base so that the thickness of the wet coating film becomes 30 μm to 2,000 μm, and the coating film is heated at a temperature of 20° C. to 200° C. for 10 minutes to 24 hours to obtain a dried coating film.

[0159] The lightness (L* value) of the coating film obtained from the coating composition may be 80 or less, for example, 70 or less. It may also be, for example, 5 or more, or 15 or more.

[0160] The lightness of the coating film can be measured using a colorimeter, for example, in accordance with JIS K 5600-4-4-3.2 and JIS K 5600-4-5. The colorimeter can be, for example, a CM-600d (manufactured by Konica Minolta).

[0161] In this specification, the coating film used to measure lightness, near-infrared reflectance, and spectral reflectance can be formed, for example, by the following method. The coating composition is applied to an asphalt felt sheet 430 (manufactured by Shizuoka Rekisei Kogyo Co., Ltd.) as a substrate so that the wet coating film has a thickness of 30 μm to 2,000 μm, and then heated at a temperature of 20°C to 200°C for 10 minutes to 24 hours to obtain a dried coating film. The portion for measuring lightness (L* value) may be the lightness of the portion of the resulting dried coating film where the substrate is white. Note that "the thickness of the wet coating film or the thickness of the wet coating film after drying (thickness of the dry coating film) is 30 μm to 2,000 μm" means that the minimum film thickness of the wet coating film or the dry coating film is 30 μm or more and the maximum film thickness is 2,000 μm or less.

[0162] Since the wavelength range of near-infrared light is close to the visible light range, a coating composition with high near-infrared reflectance tends to have high visible light reflectance and high brightness. Generally, when the brightness (L* value) falls below 80, the near-infrared reflectance tends to decrease, and LiDAR visibility tends to decrease. However, by having the above-mentioned configuration, the coating composition can easily increase the near-infrared reflectance while lowering the brightness.

[0163] The brightness of the coating film measured by the above method may be, for example, 90 or less, or 80 or less, or 3 or more, or 5 or more.

[0164] The arithmetic mean height (Sa) of the coating film is preferably 10 μm or more, more preferably 10 μm or more and 300 μm or less, even more preferably 30 μm or more and 250 μm or less, and even more preferably 60 μm or more and 200 μm or less. The root mean square height (Sq) of the coating film is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 20 μm or more and 400 μm or less, even more preferably 30 μm or more and 350 μm or less, and even more preferably 70 μm or more and 300 μm or less. Having the arithmetic mean height (Sa) or root mean square height (Sq) of the coating film within the above range can improve LiDAR visibility.

[0165] The surface roughness of the coating film can be measured in accordance with ISO 25178. Based on the surface roughness measurement, the arithmetic mean height (Sa) and the root mean square height (Sq) of the coating film are calculated. The surface roughness can be measured using, for example, a laser microscope (for example, a laser microscope VK-X200 manufactured by Keyence Corporation).

[0166] In the present disclosure, the coating film used to measure the arithmetic mean height and root mean square height can be formed, for example, by the following method: The coating composition is applied to an asphalt felt sheet 430 (manufactured by Shizuoka Rekisei Kogyo Co., Ltd.) as a base so that the wet coating film has a thickness of 30 μm to 2,000 μm, and then heated at a temperature of 20° C. to 200° C. for 10 minutes to 24 hours to obtain a dry coating film.

[0167] The arithmetic mean height (also referred to as "Sa") is a parameter indicating the roughness of the surface of the coating film, and represents the average of the absolute values ​​of the differences in height at each point relative to the average plane of the surface of the coating film. A smaller Sa means that the coating film surface is flatter, and a larger Sa means that the coating film surface is more uneven. The root mean square height (also referred to as "Sq") is a parameter equivalent to the standard deviation of the distance from the average plane of the surface of the coating film.

[0168] The thickness of the wet coating film is, for example, preferably 10 to 3,000 μm, more preferably 30 to 2,500 μm, and even more preferably 30 to 2,000 μm. The thickness of the wet coating film after drying (thickness of the dry coating film) is preferably 10 to 3,000 μm, more preferably 10 to 2,000 μm, and even more preferably 10 to 1,500 μm.

[0169] A method for forming a coating film using the coating composition of the present disclosure is also included within the technical scope of the present disclosure.

[0170] The first method for producing a coating film of the present disclosure includes: applying the coating composition to a road surface to obtain a coating film; and drying the coating film to obtain a coating film for use as a detection target for sensing using near-infrared light.

[0171] The coating film is preferably applied so that the wet coating film thickness is preferably 10 μm or more and 3,000 μm or less, more preferably 20 μm or more and 2,500 μm or less, and even more preferably 30 μm or more and 2,000 μm or less. The coating can be carried out by a coating method such as spray coating, bar coater coating, air knife coating, gravure coating, brush coating, air gun coating, air electrostatic gun coating, or dip coating.

[0172] The drying temperature for drying the coating film may be preferably 20° C. or higher and 200° C. or lower, more preferably 70° C. or higher and 180° C. or lower, and even more preferably 80 to 140° C. The drying time may be preferably 10 minutes to 24 hours, more preferably 10 to 60 minutes, and even more preferably 15 to 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. may be employed.

[0173] The method for producing a second coating film of the present disclosure comprises: applying a second paint composition onto a road surface to obtain a second coating film; scattering aggregate (E) onto the second coating film; and drying the second coating film to obtain a coating film for detection of an object to be sensed using near-infrared light; wherein the second coating composition comprises the coating film-forming resin (A) and the color pigment (B); and the color pigment (B) comprises at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance; and the aggregate (E) comprises aggregate (E1) having a near-infrared reflectance of 5% or more.

[0174] The coating composition of the present disclosure also includes a coating composition in which aggregate (E) is scattered on the second coating film.

[0175] The second coating composition contains the film-forming resin (A) and the color pigment (B), and may further contain the crosslinking agent (C), the solvent (D), and the other additives. The second coating composition may further contain an aggregate (E). The types and amounts of each of the components may be similar to the types and amounts of each component that may be contained in the coating composition of the present disclosure.

[0176] The second coating film is preferably applied so that the wet coating film thickness is preferably 10 μm or more and 3,000 μm or less, more preferably 20 μm or more and 2,500 μm or less, and even more preferably 30 μm or more and 2,000 μm or less. The coating can be carried out by a coating method such as spray coating, bar coater coating, air knife coating, gravure coating, brush coating, air gun coating, air electrostatic gun coating, or dip coating.

[0177] The drying temperature for drying the second coating film may be preferably 20° C. or higher and 200° C. or lower, more preferably 70° C. or higher and 180° C. or lower, and even more preferably 80 to 140° C. The drying time may be preferably 10 minutes to 24 hours, more preferably 10 to 60 minutes, and even more preferably 15 to 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. may be employed.

[0178] In the method for forming the second coating film, after spraying the aggregate (E), a second coating film may be further applied before drying the second coating film to form a third coating film. That is, the method for producing a third coating film of the present disclosure includes: applying a third coating composition on a road surface to obtain a third coating film; spraying aggregate (E) on the third coating film; and applying a fourth coating composition on the third coating film onto which the aggregate (E) has been sprayed to obtain a fourth coating film; drying the third coating film and the fourth coating film to obtain a coating film for a detection target in sensing using near-infrared light, wherein the third coating composition comprises the coating film-forming resin (A) and the color pigment (B), and the fourth coating composition comprises the coating film-forming resin (A) and the color pigment (B). The color pigment (B) includes at least one pigment selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more, where the reflectance in a wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance, and the aggregate (E) includes an aggregate (E1) having a near-infrared reflectance of 5% or more.

[0179] The coating composition of the present disclosure also includes a coating in which aggregate (E) is scattered on the third coating film and a fourth coating film is then formed.

[0180] The third or fourth coating composition contains the film-forming resin (A) and the color pigment (B), and may further contain the crosslinking agent (C), the solvent (D), and the other additives. The second coating composition may further contain an aggregate (E). The types and amounts of each of the components may be similar to the types and amounts of each component that may be contained in the coating composition of the present disclosure.

[0181] The third coating composition and the fourth coating composition may be the same or different. For example, the near-infrared reflectance of a coating film formed from the fourth coating composition may be higher than the near-infrared reflectance of a coating film formed from the third coating composition. Furthermore, the pigment mass concentration of the pigment (B1) in the fourth coating composition may be higher than the pigment mass concentration of the pigment (B1) in the third coating composition.

[0182] The third and fourth coating films are preferably applied so that the wet coating film thickness is preferably 10 μm or more and 3,000 μm or less, more preferably 20 μm or more and 2,500 μm or less, and even more preferably 30 μm or more and 2,000 μm or less. The coating can be carried out by a coating method such as spray coating, bar coater coating, air knife coating, gravure coating, brush coating, air gun coating, air electrostatic gun coating, or dip coating.

[0183] The drying temperature for drying the third and fourth coating films may be preferably 20° C. or higher and 200° C. or lower, more preferably 70° C. or higher and 180° C. or lower, and even more preferably 80 to 140° C. The drying time may be preferably 10 minutes to 24 hours, more preferably 10 to 60 minutes, and even more preferably 15 to 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. may be employed.

[0184] In the first to third manufacturing methods, the coating composition is applied to a road surface, but the present invention is not limited to this, and the coating composition may be applied to other substrates, such as metal plates and members made of metal plates, as well as plastic members, inorganic material members, wooden members, and pavements such as road surfaces.

[0185] Examples of the metal sheet include galvanized steel sheets, zinc-aluminum alloy-plated steel sheets, aluminum alloy-plated steel sheets, hot-dip zinc-aluminum-magnesium alloy-plated steel sheets, stainless steel sheets, and cold-rolled steel sheets, all of which are manufactured by hot-dip or electrolytic processes. In addition to these steel sheets or plated steel sheets, metal sheets such as aluminum sheets (including aluminum alloy sheets) can also be coated. The metal sheet is preferably surface-treated. Specifically, the metal sheet is preferably subjected to a pretreatment such as alkaline degreasing, hot water washing, or water washing, followed by a chemical conversion treatment. The chemical conversion treatment may be performed by a known method, and examples include non-chromate treatments such as chromate treatment and zinc phosphate treatment. The surface treatment can be appropriately selected depending on the steel sheet to be used, but a treatment that does not contain heavy metals is preferred.

[0186] Examples of the plastic member include an acrylic plate, a polyvinyl chloride plate, a polycarbonate plate, an ABS plate, a polyethylene terephthalate plate, and a polyolefin plate.

[0187] Examples of the inorganic member include ceramic building materials and glass substrates described in JIS A 5422, JIS A 5430, etc., such as calcium silicate boards, pulp cement boards, slag gypsum boards, magnesium carbonate boards, asbestos-perlite boards, wood chip cement boards, hard wood cement boards, concrete boards, and lightweight aerated concrete boards.

[0188] Examples of the wooden members include lumber, laminated lumber, plywood, particle board, fiber board, improved wood, chemically treated wood, and floorboards.

[0189] Examples of the pavement such as road surfaces include asphalt pavement, concrete pavement, and brick pavement.

[0190] Specific examples of the substrate include structures, articles, etc. that may become obstacles during automatic driving of automobiles, such as various products for sale, driving paths, road structures (e.g., pavements, road markings, sidewalks, crosswalks, drainage facilities, at-grade intersections, bridges, earthworks, tunnels, turnouts, traffic safety facilities (e.g., grade separation facilities, guardrails, guard poles, protective fences, lighting facilities, delineators, road reflectors, etc.), traffic islands, bus stops, parking lanes, parking lots, etc.), various building structures and their internal equipment, railway structures, various protective facilities, various vehicles and their accessories, pedestrian wear, utility poles, and the interior walls of various building structures.

[0191] Furthermore, a sensing method using near-infrared light and the coating film is also included within the technical scope of the present invention. For example, in a sensing method (time-of-flight: ToF) for measuring the distance between a vehicle and a painted object, in which near-infrared light of a specific wavelength is irradiated from a traveling vehicle, the light is reflected by the object, the reflected light is detected, and the distance from the vehicle to the painted object is calculated based on the time required for reflection, the coated object can be obtained by coating the coated object with the coating composition. Also, in a sensing method (frequency-modulated continuous wave: FMCW) for measuring the distance between a vehicle and a painted object, in which near-infrared light of a specific wavelength is irradiated from a traveling vehicle, the light is reflected by the object, the reflected light is detected, and the distance from the vehicle to the object is calculated based on the change in the frequency difference between the irradiated light and the reflected light, the coated object can be obtained by coating the coated object with the coating composition.

[0192] The paint composition and coating film can realize a marking that exhibits high retroreflectivity (particularly at high incidence angles) even when formed on a road surface, without being mistaken for a white line. Such a marking can improve the detection accuracy of near-infrared light in LiDAR technology, and preferably can improve the detection accuracy of near-infrared light in LiDAR technology, particularly at incidence angles when long-distance recognition is assumed, while maintaining low brightness. Therefore, the paint and coating film are useful as a paint and coating film for detecting objects using near-infrared light.

[0193] The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0194] <Measurement Example 1 of Near-Infrared Reflectance and Spectral Reflectance of Pigment> Measurement example of near-infrared reflectance of organic red pigment, and spectral reflectance at wavelengths of 905 nm and / or 1,550 nm 21 parts by mass of (A-1) Aroset 5534-SB60 as a coating resin, 12.0 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co.) as a solvent, and 17.0 parts by mass of (B21-1) CINILEX DPP RED SR1C as an organic red pigment were mixed, and then dispersed using an SG mill (medium: glass beads) until the maximum particle size of the pigment coarse particles was 10 μm or less. Next, 50 parts by mass of (A-1) was added, and the mixture was mixed while stirring using a disper to obtain a base resin.

[0195] 62 parts by mass of Duranate TSA-100 (C-1) as a crosslinking agent and 38 parts by mass of T-SOL 100 (manufactured by Exxon Chemical Co.) as a solvent (D2-1) were mixed with stirring using a disper to obtain a curing agent.

[0196] The base resin and curing agent obtained above were mixed in a mass ratio of 9:1 to obtain a coating composition (pigment mass concentration: 30 mass%). The obtained coating composition was applied to a black and white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) using an 8 mil doctor blade so that the dry film thickness was 50 μm, and after drying at 60° C. for 20 minutes, it was left to stand at room temperature for 1 day to obtain a coating film.

[0197] For the resulting coating film, the reflectance of the white-based portion was measured in 2-nm wavelength increments in the wavelength range of 800 to 2,500 nm using a spectrophotometer (Shimadzu Corporation, SHIMADZU-UV3600) according to a method in accordance with JIS K 5602. The arithmetic mean value of the reflectance at each wavelength obtained was taken as the near-infrared reflectance of the inorganic red pigment. The near-infrared reflectances at 905 and 1,550 nm are the spectral reflectance values ​​at each wavelength.

[0198] The near-infrared reflectance and spectral reflectance of each of the other pigments were measured in the same manner as in Measurement Example 1 of Near-Infrared Reflectance and Spectral Reflectance of Pigments, except that the type and mass concentration of each pigment were set to the amounts shown in Table 1.

[0199]

[0200] <Production Example 1> Example of production of a white pigment paste 22 parts by mass of (A-1) Aroset 5534-SB60 as a film-forming resin, 7 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co.) as a solvent, and 34 parts by mass of (B1-1) TIPAQUE CR-97 as a white pigment were mixed, and then dispersed using an SG mill (medium: glass beads) until the maximum particle size of the pigment coarse particles was 10 μm or less. Next, 37 parts by mass of (A-1) was added, and the mixture was mixed while stirring using a disper to obtain a white pigment paste (W-1).

[0201] <Production Examples 2 to 7> Pigment pastes of each pigment were obtained in the same manner as in Production Example 1, except that the types and amounts of the film-forming resin, solvent, and pigment used were changed as shown in Table 2.

[0202]

[0203] <Example of production of PWC adjusting clear coat> 83 parts by mass of (A-1) Aroset 5534-SB60 (manufactured by Nippon Shokubai Co., Ltd.) as a coating film forming resin and 17 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent were mixed while stirring using a disper to obtain a PWC adjusting clear coat.

[0204] Example 1 0.6 parts by mass of the yellow pigment paste (Y-1), 38.7 parts by mass of the white pigment paste (W-1), 33.7 parts by mass of the black pigment paste (BK2-1), and 89.2 parts by mass of PWC adjusting clear were mixed while stirring with a disper to obtain a main agent (S-1).

[0205] As a crosslinking agent, 62 parts by weight of Duranate TSA-100 (C-1) and 38 parts by weight of T-SOL 100 (manufactured by Exxon Chemical Co.) were mixed with stirring using a disper to obtain a curing agent (K-1).

[0206] <Coating Film (Test Piece) Production Example 1> 162.2 parts by mass of the base agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed while stirring with a disperser, and 54.1 parts by mass of filler (E1-1) was added and mixed to obtain coating composition 1 (pigment mass concentration: 14% by mass). The obtained coating composition 1 was applied to asphalt felt 430 (70 x 150 mm, manufactured by Shizuoka Rekisei Kogyo Co., Ltd.) so that the wet coating film was 2,000 μm thick, dried at 60 ° C. for 20 minutes, and then left to stand at room temperature for 1 day to obtain test piece 1. The base agent (S-1) and curing agent (K-1) were mixed in a mass ratio of 9:1.

[0207] Each coating film (test piece) was obtained in the same manner as in Coating Film (Test Piece) Production Example 1, except that the types and amounts of pigment paste, PWC adjusting clear, crosslinking agent, and solvent used were changed as shown in Table 3. When other materials were included in the coating composition, the other materials were mixed with various pigment pastes and PWC adjusting clear when producing the main agent to prepare the main agent.

[0208] Examples 2 to 12: Base resins and curing agents were prepared and test specimens were obtained in the same manner as in Example 1, except that the type and amount of each component was changed as shown in Table 4. Note that the total mass concentration of aggregate (E1) in the table should be interpreted as the amount of other aggregate (E2) when other aggregate (E2) is used. Note that the amounts of each component, pigment paste, and PWC adjusting clear coat in Table 4 are the amounts of each component, pigment paste, and PWC adjusting clear coat including volatile components such as solvents.

[0209] Example 13 162.2 parts by mass of the base agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed while stirring with a disperser to obtain a coating composition 13 (pigment mass concentration: 14% by mass). The obtained coating composition 13 was applied to asphalt felt 430 (manufactured by Shizuoka Rekisei Kogyo Co., Ltd.) so that the wet film thickness was 2,000 μm, and 54.1 parts by mass of filler (E1-5) was sprayed onto the surface so that it was visually uniform. After drying at 60 ° C. for 20 minutes, the mixture was allowed to stand at room temperature for 1 day to obtain a test piece 13. The base agent (S-1) and curing agent (K-1) were mixed in a mass ratio of 9:1.

[0210] Example 14 162.2 parts by mass of the base agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed while stirring with a disperser to obtain a coating composition 13 (pigment mass concentration: 14% by mass). The obtained coating composition 13 was applied to asphalt felt 430 (manufactured by Shizuoka Rekisei Kogyo Co., Ltd.) to a wet film thickness of 1,000 μm. 54.1 parts by mass of filler (E1-5) was sprayed onto the surface so that it was visually uniform, and then coating composition 13 was applied thereon to a wet film thickness of 1,000 μm. After drying at 60°C for 20 minutes, the coating was allowed to stand at room temperature for 1 day to obtain a test piece 14. The base agent (S-1) and curing agent (K-1) were mixed in a mass ratio of 9:1.

[0211] The details of each component shown in Table 4 below and used in the Examples and Comparative Examples are as follows: Film-forming resin (A) (A-1) Aroset 5534-SB60 (acrylic polyol resin, manufactured by Nippon Shokubai Co., Ltd.): weight average molecular weight: 50,000, acid value: 10 mgKOH / g, hydroxyl value: 38 mgKOH / g, solid content: 60 mass% Crosslinker (C) (C-1) Duranate TSA-100 (HDI isocyanurate polyisocyanate, manufactured by Asahi Kasei Corporation); NCO content: 20.6%, solid content: 100 mass% Solvent (D) (D2-1) T-SOL 100 (aromatic hydrocarbon solvent, manufactured by Exxon Chemical Co., Ltd.)

[0212] The details of the aggregate (E1) and other aggregate (E2) shown in Table 4 below, which were used in the Examples and Comparative Examples, are shown in Table 3. In Table 3, the mixed particles are SiO ２ , Al２ O ３ , Fe ２ O ３ , TiO ２ , CaO and Cr ２ O ３ It is a mixed particle of

[0213] The near-infrared reflectance, spectral reflectance at wavelengths of 905 nm and 1,550 nm, particle size distribution and average particle size measured by a sieving method of the aggregate are shown in Table 3. Sieves with openings of 180 μm, 212 μm, 300 μm, 425 μm, 500 μm and 1,000 μm were used for the sieving method.

[0214]

[0215] <Evaluation Methods> 1) Coating Film Brightness The brightness (L* value) of the coating film surface of the test pieces obtained in the Examples and Comparative Examples was measured using a color difference meter CM-500 (manufactured by Konica Minolta) in accordance with JIS K 5600-4-4-3.2 and JIS K 5600-4-5.

[0216] 2) Near-infrared reflectance and spectral reflectance For the test pieces obtained in the examples and comparative examples, the reflectance in the wavelength range of 800 to 2,500 nm was measured at wavelength intervals of 2 nm using a spectrophotometer (Shimadzu Corporation, SHIMADZU-UV3600) according to a method conforming to JIS K-5602. The arithmetic mean value of the reflectance at each wavelength obtained was taken as the near-infrared reflectance of the coating film. The near-infrared reflectance at 905 and 1,550 nm is the spectral reflectance value at each wavelength.

[0217] 3) Surface Roughness The arithmetic mean height (Sa: μm) and root mean square height (Sq: μm) of the coating film surfaces of the test pieces obtained in the Examples and Comparative Examples were measured in accordance with JIS B 0601 using a laser microscope VK-X200 (manufactured by Keyence Corporation).

[0218] 4) LiDAR visibility The test pieces obtained in the examples and comparative examples were observed from a distance of 3 m using a LiDAR Mid-40 (manufactured by Livox, wavelength: 905 nm, angle of incidence: 0° and 80°). The state of the test piece obtained in the image was visually observed, and the reflectance was measured at 10 points arbitrarily selected from the entire test piece. The arithmetic mean value was taken as the LiDAR reflectance of the test piece, and was evaluated according to the following criteria. A score of 3 or more was considered to be pass. 5: The LiDAR reflectance of the test piece was 100 or more 4: The LiDAR reflectance of the test piece was 50 or more and less than 100 3: The LiDAR reflectance of the test piece was 30 or more and less than 50 2: The LiDAR reflectance of the test piece was 10 or more and less than 30 1: The LiDAR reflectance of the test piece was less than 10

[0219] 5) Slip Resistance For the test specimens obtained in the examples and comparative examples, the slip resistance value (BPN: British Pundulm Number) was measured in accordance with "6-5 Measurement Method of Skid Resistance of Pavement Surfaces" in the "Pavement Survey and Test Method Handbook (2019 Edition)" compiled by the Japan Road Association, and slip resistance was evaluated. That is, the measurement was performed using a slip resistance tester TR-300 (portable skid resistance tester: manufactured by Freesia Macross), spraying tap water on the surface of the test specimen fixed to the horizontal ground, swinging the rubber plate at the end of the pendulum down from a certain height, bringing the test specimen surface into contact with the rubber plate, and reading the attenuation due to friction between the test specimen surface and the rubber plate (resistance value at that time) on the scale. The test was performed at 23 ° C (t). The slip resistance value (BPN value) was the average value of five measurements in which the measurement value fluctuation was within 3 BPN. The larger this value, the greater the slip resistance, meaning better slip resistance. The slip resistance value is calculated by converting the actual measured slip resistance value (C ｔ ) and the slip resistance value at 20 ° C (C ２０ ) is the value converted into C ２０ = -0.0071 x t ２ +0.9301×t-15.79+C ｔThe evaluation criteria are as follows, with 3 or more being considered pass: 5: 80 BPN or more and 100 BPN or less 4: 70 BPN or more and less than 80 BPN 3: 50 BPN or more and less than 70 BPN 2: 30 BPN or more and less than 50 BPN 1: 0 BPN or more and less than 30 BPN

[0220]

[0221]

[0222] Examples 1 to 14 are examples of the present disclosure, and the detection accuracy using LiDAR technology was high, especially when the brightness (L* value) was low.

[0223] Comparative Examples 1 and 2 are examples in which no pigment or aggregate capable of reflecting near-infrared rays was used, and the slip resistance and retroreflectivity were poor, and the LiDAR visibility was not fully satisfactory. Comparative Example 3 is an example in which no aggregate was used, and the slip resistance and retroreflectivity were poor at high angles of incidence, and the LiDAR visibility was not fully satisfactory. Comparative Examples 4 to 7 are examples in which no aggregate with a near-infrared reflectance of 5% or more was used, and the retroreflectivity (especially at high angles of incidence) was not fully satisfactory.

[0224] The paint composition and coating film can realize a marking that exhibits high retroreflectivity (particularly at high incidence angles) even when formed on a road surface, without being mistaken for a white line. Such a marking can improve the detection accuracy of near-infrared light in LiDAR technology, and preferably can improve the detection accuracy of near-infrared light in LiDAR technology, particularly at incidence angles when long-distance recognition is assumed, while maintaining low brightness. Therefore, the paint and coating film are useful as a paint and coating film for detecting objects using near-infrared light.

Claims

1. A paint composition for a detection object for near-infrared light sensing, comprising a film-forming resin (A), a coloring pigment (B), and an aggregate (E), wherein the coloring pigment (B) includes at least one selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a colored pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more when the reflectance in the wavelength range of 800 to 2,500 nm is defined as the near-infrared reflectance, and the aggregate (E) includes an aggregate (E1) having a near-infrared reflectance of 5% or more. A paint composition for a detection object for near-infrared light sensing.

2. The paint composition for a detection object for near-infrared light sensing according to Claim 1, wherein the average particle diameter of the aggregate (E1) is 50 µm or more.

3. The paint composition for a detection object for near-infrared light sensing according to Claim 1, wherein the mass concentration of the aggregate (E) is 10% by mass or more and 70% by mass or less.

4. The paint composition for a detection object for near-infrared light sensing according to Claim 1, wherein the colored pigment includes at least one selected from the group consisting of a red pigment, a yellow pigment, and a blue pigment.

5. The paint composition for a detection object for near-infrared light sensing according to Claim 1, wherein the red pigment and the yellow pigment each include an organic pigment and / or an inorganic pigment.

6. The coloring pigment (B) is a white pigment having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1,550 nm, an organic red pigment having a spectral reflectance of 50% or more at the wavelength, an inorganic red pigment having a spectral reflectance of 20% or more at the wavelength, an organic yellow pigment having a spectral reflectance of 60% or more at the wavelength, an inorganic yellow pigment having a spectral reflectance of 20% or more at the wavelength, a blue pigment having a spectral reflectance of 40% or more at the wavelength, an organic black pigment having a spectral reflectance of 30% or more at the wavelength and an inorganic black pigment having a spectral reflectance of 15% or more at the wavelength The paint composition for a detection object for near-infrared light sensing according to Claim 1, including at least one selected from the group consisting of.

7. The paint composition for a detection object for near-infrared light sensing according to Claim 1, wherein the lightness of the formed paint film is 80 or less.

8. A coating film for a detection object of sensing using near-infrared light, formed from the coating composition according to any one of claims 1 to 7.

9. The near-infrared reflectance in the wavelength range of 800 to 2,500 nm is 15% or more, The root mean square height (Sq) measured in accordance with ISO 25178 is 10 μm or more, and / or the arithmetic mean height (Sa) measured in accordance with ISO 25178 is 10 μm or more. The coating film for a detection object of sensing using near-infrared light according to claim 8.

10. The spectral reflectance at wavelengths 905 nm and / or 1,550 nm is 20% or more, The root mean square height (Sq) measured in accordance with ISO 25178 is 10 μm or more, and / or the arithmetic mean height (Sa) measured in accordance with ISO 25178 is 10 μm or more. The coating film for a detection object of sensing using near-infrared light according to claim 8.

11. A detection object having a coating film formed using the coating composition for a detection object of sensing according to any one of claims 1 to 7.

12. In a sensing method for measuring the distance between a vehicle and a detection object, wherein near-infrared light of a specific wavelength is irradiated from a traveling vehicle, reflected by the detection object, the reflected light is detected, and the distance from the vehicle to the detection object is calculated based on the time taken for the reflection. The detection object is obtained by coating with the coating composition according to any one of claims 1 to 7. A sensing method.

13. In a sensing method for measuring the distance between a vehicle and a detection object, wherein near-infrared light of a specific wavelength is irradiated from a traveling vehicle, reflected by the detection object, the reflected light is detected, and the distance from the vehicle to the detection object is calculated based on the frequency difference between the irradiated light and the reflected light. The detection object is obtained by coating with the coating composition according to any one of claims 1 to 7. A sensing method.

14. Applying a first coating composition on a road surface to obtain a coating film, and Drying the coating film to obtain a coating film for a detection object of sensing using near-infrared light, including The first coating composition is Including a film-forming resin (A), a coloring pigment (B), and an aggregate (E), When the reflectance in the wavelength range of 800 to 2,500 nm of the coloring pigment (B) is defined as the near-infrared reflectance, the coloring pigment (B) contains at least one selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a colored pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more. The method for manufacturing a coating film, wherein the aggregate (E) includes an aggregate (E1) having a near-infrared reflectance of 5% or more.

15. Applying a second coating composition onto a road surface to obtain a second coating film. Spraying an aggregate (E) onto the second coating film, and Drying the second coating film to obtain a coating film for a detection object for sensing using near-infrared light. The second coating composition Contains a coating film-forming resin (A) and a coloring pigment (B). When the reflectance in the wavelength range of 800 to 2,500 nm of the coloring pigment (B) is defined as the near-infrared reflectance, the coloring pigment (B) contains at least one selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a colored pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more. The method for manufacturing a coating film, wherein the aggregate (E) includes an aggregate (E1) having a near-infrared reflectance of 5% or more.

16. Applying a third coating composition onto a road surface to obtain a third coating film. Spraying an aggregate (E) onto the third coating film, and Applying a fourth coating composition onto the third coating film on which the aggregate (E) has been sprayed to obtain a fourth coating film. Drying the third coating film and the fourth coating film to obtain a coating film for a detection object for sensing using near-infrared light. The third coating composition Contains a coating film-forming resin (A) and a coloring pigment (B). The fourth coating composition Contains a coating film-forming resin (A) and a coloring pigment (B). When the reflectance in the wavelength range of 800 to 2,500 nm of the coloring pigment (B) is defined as the near-infrared reflectance, the coloring pigment (B) contains at least one selected from the group consisting of a white pigment having a near-infrared reflectance of 60% or more, a colored pigment having a near-infrared reflectance of 50% or more, and a black pigment having a near-infrared reflectance of 30% or more. The method for manufacturing a coating film, wherein the aggregate (E) includes an aggregate (E1) having a near-infrared reflectance of 5% or more.

17. The coating film for a detection object for sensing using near-infrared light has a near-infrared reflectance in the wavelength range of 800 to 2,500 nm of 15% or more. The root mean square height (Sq) measured in accordance with ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured in accordance with ISO 25178 is 10 μm or more, and the manufacturing method according to any one of claims 14 to 16.

18. The coating film for the detection object of the sensing using the near-infrared light has a spectral reflectance at wavelengths of 905 nm and / or 1,550 nm of 20% or more, The root mean square height (Sq) measured in accordance with ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured in accordance with ISO 25178 is 10 μm or more, and the manufacturing method according to any one of claims 14 to 16.