Coating composition and coating film

Abstract

The purpose of the present disclosure is to provide a coating composition which, even when formed on a road surface, can form a mark that can exhibit high retroreflectivity (particularly retroreflectivity at a high incidence angle) without being mistakenly considered as a white line. This coating composition for an object to be detected, which uses near-infrared light sensing, contains (A) a coating film-forming resin, (B) a coloring pigment, and (E) an aggregate, and the coloring pigment (B) contains at least one component selected from the group consisting of: a first component selected from the group consisting of: a second component selected from the group consisting of: a first component selected from the group consisting of: a first component selected from the group consisting of: a first component selected from the group consisting of a first component and a second component selected from the group consisting of a second component and a third component; the aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more, 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, and the aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

Description

Technical Field

[0001] The present invention relates to a coating composition and a coating film, and particularly to a coating composition and a coating film for a detection object using near-infrared light sensing. Background Art

[0002] For the purpose of automating or labor-saving handling, the development of an automated guided vehicle (AGV) system is being promoted. An AGV is defined in JIS D 6801 as "a vehicle that has the function of automatically traveling and handling goods and other objects other than people in a certain area and is not used on the roads specified by the Road Traffic Law." According to the automatic driving method, AGVs are classified into three types: path-guided type in which the position of the vehicle is controlled by a certain guiding means, autonomous mobile type in which the vehicle itself has a self-position estimation function or a driving control function, and following type in which the vehicle moves in the form of following a preceding person or vehicle.

[0003] Patent Document 1 describes a coordination guidance system that includes a processor. In this system, a coating containing a crystalline rare-earth phosphor capable of converting light into electromagnetic energy is applied to a road surface, light is irradiated onto the coated surface, the generated electromagnetic energy is sensed, and converted into a processing signal, thereby determining the motion characteristics of the vehicle or the characteristics of the road surface.

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

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

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-513198;

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-131791;

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2002-188031. Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] In the path guidance type, position control of the vehicle is typically performed using magnetism, electromagnetic induction, light reflection, or the like. Among them, a guidance method using light reflection, in which the path can be easily set and changed, has attracted attention. In the guidance method using light reflection, in order to perform accurate position recognition, it is required to accurately recognize the reflected light from a specific irradiation object such as a marker. Therefore, it is desirable that such a specific irradiation object exhibits retroreflectivity (the property of reflecting light in the same direction as the incident direction).

[0013] In addition, in the autonomous mobile type, in order to estimate its own position, LiDAR (Laser Imaging Detection and Ranging) technology is used. LiDAR is one of the remote sensing technologies using light, and is a technology for irradiating an object such as a road surface with near-infrared light, visible light, and / or ultraviolet light, and detecting the distance and azimuth from the irradiation position to the object by measuring the light reflected and / or scattered by the object. LiDAR is widely used not only in AGVs but also in automotive autonomous driving technology, electronic devices, and various industries. Even when applying LiDAR technology to AGVs or autonomous driving technology, it is desirable that objects such as road surfaces exhibit retroreflectivity. In particular, in AGVs or autonomous driving, since it is assumed that laser light is irradiated onto a road surface at a long distance from the vehicle and its reflected light is detected, it is also necessary to be able to handle cases where the incident angle is a high angle. In the case of a low incident angle, since the difference between the incident angle and its reflection angle is small, it is relatively easy to exhibit retroreflectivity; however, in the case of a high incident angle, since light reflection needs to be performed in a direction significantly different from that of normal total reflection, it becomes difficult to exhibit retroreflectivity. It should be noted that the incident angle is the angle measured from the normal line erected on the reflecting surface.

[0014] As a means for exhibiting retroreflectivity on a marker or a road surface, for example, a method of applying a paint containing glass beads can be cited. However, since glass beads also strongly reflect visible light, especially on a road surface, in the case of irradiating strong light such as sunlight or the headlights of a car, it may be mistaken for a white line. On the other hand, if the brightness of the paint is reduced, the LiDAR detectability is reduced. In the above-mentioned technologies known in the past, it has been difficult to form a marking that can exhibit high retroreflectivity (especially retroreflectivity at a high incident angle) without being mistaken for a white line.

[0015] The present disclosure has been made in view of such circumstances, and an object thereof is to provide a coating composition that can form a marking that can exhibit high retroreflectivity (especially retroreflectivity at a high incident angle) without being mistaken for a white line even when formed on a road surface.

[0016] Means for Solving the Problem

[0017] The present invention includes the following inventions.

[0018] [1] A coating composition for a detection object using near-infrared light sensing, the coating composition for a detection object using near-infrared light sensing contains a film-forming resin (A), a coloring pigment (B), and an aggregate (E), wherein,

[0019] The coloring pigment (B) contains at least one selected from the following: when the reflectance in the wavelength range of 800 to 2500 nm is defined as the near-infrared reflectance, 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,

[0020] The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

[0021] [2][1] The coating composition for a detection object using near-infrared light sensing according to [1], wherein the average particle size of the aggregate (E1) is 50 μm or more.

[0022] [3][1] or [2] The coating composition for a detection object using near-infrared light sensing 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.

[0023] [4][1] to [3] The coating composition for a detection object using near-infrared light sensing according to any one of [1] to [3], wherein the colored pigment contains at least one selected from red pigments, yellow pigments, and blue pigments.

[0024] [5][1] to [4] The coating composition for a detection object using near-infrared light sensing according to any one of [1] to [4], wherein the red pigment and the yellow pigment each contain an organic pigment and / or an inorganic pigment.

[0025] [6][1] to [5] The coating composition for a detection object using near-infrared light sensing according to any one of [1] to [5], wherein the coloring pigment (B) contains at least one selected from the following:

[0026] A white pigment having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1550 nm,

[0027] An organic red pigment having a spectral reflectance of 50% or more at the said wavelength,

[0028] An inorganic red pigment having a spectral reflectance of 20% or more at the said wavelength,

[0029] An organic yellow pigment having a spectral reflectance of 60% or more at the said wavelength,

[0030] An inorganic yellow pigment having a spectral reflectance of 20% or more at the said wavelength,

[0031] A blue pigment having a spectral reflectance of 40% or more at the said wavelength,

[0032] An organic black pigment having a spectral reflectance of 30% or more at the said wavelength, and

[0033] An inorganic black pigment having a spectral reflectance of 15% or more at the said wavelength.

[0034] The coating composition for a detection object using near-infrared light sensing according to [7][1] to [6], wherein the lightness of the formed coating film is 80 or less.

[0035] [8] A coating film for a detection object using near-infrared light sensing, having a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm,

[0036] The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

[0037] [9] A coating film for a detection object using near-infrared light sensing, formed from the coating composition according to any one of [1] to [7].

[0038]

[10] The coating film for a detection object using near-infrared light sensing according to [9], having a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm,

[0039] The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

[0040]

[11] The coating film for a detection object using near-infrared light sensing according to any one of [9], having a spectral reflectance of 20% or more at a wavelength of 905 nm and / or 1550 nm,

[0041] The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

[0042]

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

[0043]

[13] A sensing method for measuring the distance between a vehicle and a detection object. In this sensing method, near-infrared light of a specific wavelength is irradiated from a moving vehicle, the near-infrared light is 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 required for the reflection.

[0044] Wherein, the coating is obtained by coating the coating composition according to any one of [1] to [7].

[0045]

[14] A sensing method for measuring the distance between a vehicle and a detection object. In this sensing method, near-infrared light of a specific wavelength is irradiated from a moving vehicle, the near-infrared light is 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.

[0046] Wherein, the coating is obtained by coating the coating composition according to any one of [1] to [7].

[0047]

[15] A coating film manufacturing method, including:

[0048] Coating a first coating composition on a road surface to obtain a coating film, and

[0049] Drying the coating film to obtain a coating film for a detection object for sensing using near-infrared light.

[0050] The first coating composition contains a film-forming resin (A), a coloring pigment (B), and an aggregate (E).

[0051] The coloring pigment (B) contains at least one selected from the following: when the reflectance in the wavelength range of 800 to 2500 nm is set as the near-infrared reflectance, a white pigment with a near-infrared reflectance of 60% or more, a colored pigment with a near-infrared reflectance of 50% or more, and a black pigment with a near-infrared reflectance of 30% or more.

[0052] The aggregate (E) contains an aggregate (E1) with a near-infrared reflectance of 5% or more.

[0053]

[16] A coating film manufacturing method, including:

[0054] Coating a second coating composition on a road surface to obtain a second coating film,

[0055] Scattering the aggregate (E) on the second coating film, and

[0056] Drying the second coating film to obtain a coating film for a detection object for sensing using near-infrared light.

[0057] The second coating composition contains a film-forming resin (A) and a coloring pigment (B).

[0058] The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance.

[0059] The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

[0060]

[17] A method for manufacturing a coating film, comprising:

[0061] Coating a third coating composition on a road surface to obtain a third coating film,

[0062] Spreading the aggregate (E) on the third coating film, and

[0063] Coating a fourth coating composition on the third coating film on which the aggregate (E) has been spread to obtain a fourth coating film,

[0064] Drying the third coating film and the fourth coating film to obtain a coating film for a detection object using near-infrared light sensing,

[0065] The third coating composition contains a film-forming resin (A) and a coloring pigment (B),

[0066] The fourth coating composition contains a film-forming resin (A) and a coloring pigment (B),

[0067] The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance.

[0068] The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

[0069]

[18] The manufacturing method according to any one of

[15] to

[17] , wherein the coating film for a detection object using near-infrared light sensing has a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm,

[0070] The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

[0071] The production method according to any one of

[19] and

[15] to

[17] , wherein the spectral reflectance of the coating film for the detection object for sensing using near-infrared light is 20% or more at a wavelength of 905 nm and / or 1550 nm,

[0072] The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

[0073] Advantages of the Invention

[0074] The coating composition and the coating film of the present invention can achieve a marking that exhibits high retroreflectivity (especially retroreflectivity at a high incident angle) without being misrecognized as a white line even when formed on a road surface. According to such a marking, the detection accuracy of near-infrared rays in LiDAR technology can be improved, and preferably, the detection accuracy of near-infrared rays in LiDAR technology can be improved even at low lightness, especially the detection accuracy at the incident angle assumed for long-distance recognition. Detailed Embodiments

[0075] The coating composition is a coating composition for a detection object for sensing using near-infrared light, which contains a film-forming resin (A), a coloring pigment (B), and an aggregate (E), wherein,

[0076] The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance,

[0077] The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more,

[0078] For a detection object for sensing using near-infrared light.

[0079] According to the coating composition of the present disclosure, even when formed on a road surface, a marking that exhibits high retroreflectivity (especially retroreflectivity at a high incident angle) without being misrecognized as a white line can be achieved. The present disclosure should not be limited to being explained by a specific theory, but it is considered that the reason why the coating composition of the present disclosure can exhibit such an effect is as follows. The coating composition of the present disclosure uses a pigment having a specific near-infrared reflectance as the coloring pigment, so that the obtained coating film can reflect near-infrared rays. Moreover, the coating composition of the present disclosure also includes an aggregate having a specific near-infrared reflectance. Therefore, it is considered that even when a marking is formed on a road surface, retroreflectivity to near-infrared rays can be exhibited.

[0080] Specifically, the sensing may be remote sensing technology, which may irradiate near-infrared light on the detection object, and detect the reflected light and / or scattered light from the irradiation position, so as to determine the distance or azimuth from the near-infrared light emission position to the irradiation position.

[0081] The wavelength of the near-infrared light used for the sensing is preferably 800 nm or more, more preferably 900 nm or more, preferably 2500 nm or less, more preferably 2000 nm or less, and further preferably 1600 nm or less. The shorter the wavelength of the near-infrared light, the higher the straightness, and the longer the wavelength, the easier it is to exclude the influence of sunlight. Currently, the wavelengths mainly used in sensing are 905 nm and / or 1550 nm.

[0082] Hereinafter, the detection object of the sensing using near-infrared light may sometimes be simply referred to as "coating composition" with the coating composition.

[0083] [Coating-forming resin (A)]

[0084] The coating-forming resin (A) is a resin capable of forming a coating film, and resins commonly used in the coating field can be used. As the coating-forming resin (A), thermosetting resins, room-temperature curable resins, or photocurable resins such as acrylic resins, polyester resins, polyurethane resins, alkyd resins, polyether resins, fluororesins, epoxy resins, silicone resins, or urea resins can be cited, and it is preferably to contain one or more selected from acrylic resins, polyester resins, polyurethane resins, and urea resins. In addition, for the coating-forming resin (A), a coating film can be formed by the coating-forming resin (A) alone, or a coating film can be formed by the action of the crosslinking agent (C) described later. As the coating-forming resin (A), one kind can be used, or two or more kinds can be used in combination.

[0085] The acrylic resin represents a polymer having a unit 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 include monomers 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.

[0086] As the monomer having a (meth)acryloyl group, (meth)acrylic acid; (meth)acrylic acid alkyl esters having a linear or branched alkyl group with 1 to 20 carbon atoms; (meth)acrylic acid hydroxyalkyl esters such as (meth)acrylic acid hydroxyethyl ester, (meth)acrylic acid hydroxypropyl ester, (meth)acrylic acid hydroxybutyl ester, N-hydroxymethyl(meth)acrylamide, etc.; lactone adducts of the (meth)acrylic acid monomers having a hydroxyl group; (meth)acrylonitrile, etc. can be cited.

[0087] As monomers having ethylenically unsaturated groups, in addition to the monomers having (meth)acryloyl groups, there are also monomers having carboxyl groups such as crotonic acid, itaconic acid, fumaric acid, etc.; acid anhydrides of the monomers having carboxyl groups; vinyl monomers such as styrene, etc.

[0088] 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 polymer of a cyclic ester, a reaction product of the reaction product of the polyol and the polycarboxylic acid and a cyclic ester, etc.

[0089] The polyol is a compound having two or more hydroxyl groups in one molecule. For example, 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, etc.; alicyclic polyols such as hydrogenated bisphenol A, 1,4-cyclohexanedimethanol, etc.; aromatic polyols such as bisphenol A, hydroxyalkylated bisphenol A, etc.; polyols having 3 or more functional groups such as glycerin, mannitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, dipentaerythritol, etc.; sugar alcohols such as sorbitol, etc.; tris(hydroxyethyl) isocyanate; N,N-bis(2-hydroxyethyl) dimethylhydantoin, etc.

[0090] The number of hydroxyl groups contained in the polyol is preferably two or more in one molecule, may be three or more, preferably six or less, and more preferably four or less.

[0091] As the polyol, one kind can be used, or two or more kinds can be used in combination.

[0092] The polycarboxylic acid refers to a compound having two or more carboxyl groups in one molecule. As the polycarboxylic acid, aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.; alicyclic polycarboxylic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclohexane-1,4-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, methyl-5-norbornene-2,3-dicarboxylic acid, etc.; aliphatic polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, dodecenyl succinic acid, etc.; hydroxy acids of lactose; acid anhydrides of the aromatic polycarboxylic acids, the alicyclic polycarboxylic acids, the aliphatic polycarboxylic acids, etc. As the polycarboxylic acid, one kind can be used, or two or more kinds can be used in combination.

[0093] As the cyclic ester, ε-caprolactone, etc. can be cited.

[0094] The polyester resin further includes a modified product of the polyester resin. Modification of the resin can be carried out by reacting a modifier with the ends of the main chain constituting the resin. As the modifier, compounds having reactive groups such as isocyanate groups, hydroxyl groups, carboxyl groups, or having a silicone skeleton, etc. can be cited. As the modified product of the polyester resin, urethane-modified polyester resin, epoxy-modified polyester resin, acrylic-modified polyester resin, silicone-modified polyester resin, etc. can be cited.

[0095] The urethane resin is a reaction product of a polyol and a polyisocyanate, a reaction product of such a reaction product and a chain extender used as required, etc.

[0096] The polyol refers to a compound having two or more hydroxyl groups in one molecule. As the polyol, 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, 1,6-hexanediol, etc. can be cited; alicyclic polyols such as hydrogenated bisphenol A, 1,4-cyclohexanedimethanol, etc.; aromatic polyols such as bisphenol A, hydroxyalkylated bisphenol A (especially bisphenol hydroxypropyl ether), etc.; polyols having three or more functional groups such as glycerin, mannitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, dipentaerythritol, etc.; high molecular weight polyols such as polyether polyol, acrylic polyol, polyurethane polyol, polyester polyol, polyester amide polyol, etc. (for example, polyols having a weight average molecular weight of 800 or more). As the polyol, one kind can be used, or two or more kinds can be used in combination.

[0097] The number of hydroxyl groups contained in the polyol is two or more, and can also be three or more, preferably six or less, and more preferably four or less.

[0098] 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, hexamethylene diisocyanate; alicyclic polyisocyanates such as 1,3-cyclopentane diisocyanate, 1,4-dicyclohexylmethane diisocyanate, 1,2-cyclohexane diisocyanate, isophorone diisocyanate, norbornane diisocyanate methyl, hydrogenated xylylene diisocyanate; aromatic polyisocyanates such as 1,4-toluene diisocyanate, 1,6-toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, m-xylylene diisocyanate, naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate; and polymers such as biuret bodies, isocyanurate bodies, uretdione bodies, urethane bodies of the aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate. As the polyisocyanate, one kind can be used, or two or more kinds can be used in combination.

[0099] The chain extender refers to a compound having one or more active hydrogen atoms in one molecule, and water or an amine compound can be used. Examples of the amine compound include aliphatic polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine; aromatic polyamines such as toluenediamine, xylylenediamine, diaminodiphenylmethane; alicyclic polyamines such as diaminocyclohexylmethane, piperazine, 2,5-dimethylpiperazine, isophoronediamine; hydrazine compounds such as hydrazine, succinic dihydrazide, adipic dihydrazide, phthalic dihydrazide; and alkanolamines such as hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl)amino]ethanol, 3-aminopropanediol.

[0100] In one embodiment, as the urethane resin, a polyester-based urethane resin, a polyether-based urethane resin, and a polycarbonate-based urethane resin can be used.

[0101] Examples of the epoxy resin include an epoxy resin having two or more epoxy groups in one molecule. Specifically, glycidyl ester resins; glycidyl ether type resins such as condensation products of bisphenol A and epichlorohydrin, condensation products of bisphenol F and epichlorohydrin; and alicyclic epoxy resins, linear aliphatic epoxy resins, bromine-containing epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, etc.

[0102] Examples of the urea resin include reaction products of polyamine compounds and polyisocyanate compounds. For the polyamine compound and the polyisocyanate compound, a two-component coating composition in which they are separately blended can also be prepared.

[0103] The polyamine compound is a compound having two or more amino groups and contains at least one selected from aliphatic polyamine compounds, alicyclic polyamine compounds and aromatic polyamine compounds, and preferably contains at least one selected from aliphatic polyamine compounds and alicyclic polyamine compounds.

[0104] The amino group is preferably a primary amino group or a secondary amino group. In one embodiment, the amino group may be present in the molecular chain of the polyamine compound or at the molecular end. The polyamine compound may be, for example, R 12 HN-R 11 -NHR 12 (Among them, R 1 Indicates 2-valent C 1-30 Hydrocarbon, R 11 The -CH2- contained in it can be replaced by -O-, -CO- or -NR 12 -, R 12 Indicates 1 price C 1-30 As the C 1-30 Hydrocarbon groups include C 1-30 Aliphatic hydrocarbon group, C 3-30 Alicyclic hydrocarbon group and C 6-30 Aromatic hydrocarbon group.

[0105] The aliphatic polyamine compound is a polyamine compound that does not have a ring structure in its molecular structure. Examples of such aliphatic polyamine compounds include alkylene polyamine compounds, polyalkylene polyamine compounds, and other aliphatic polyamine compounds.

[0106] Examples of the alkylene polyamine compound include methylenediamine, ethylenediamine, 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.

[0107] Examples of the polyalkylene polyamine compound include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexamethylenetetramine.

[0108] Examples of 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 esteramine represented by the following formula (11).

[0109] The alicyclic polyamine compound refers to a polyamine compound having an alicyclic structure in its molecular structure.

[0110] As the alicyclic polyamine compound, for example, 1,4-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), 4,4'-isopropylidenebis(cyclohexylamine), 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane (e.g., norbornanediamine), bis(aminomethyl)cyclohexane, diaminodicyclohexylmethane (e.g., 4,4'-diaminodicyclohexylmethane, etc.), isophoronediamine, menthanediamine (MDA), 1,4-bis-(8-aminopropyl)-piperazine, piperazine-1,4-diazacycloheptane, 1-(2'-aminoethylpiperazine), 1-[2'-(2”-aminoethylamino)ethyl]piperazine, 1,11-diazacycloeicosane, 1,15-diazacyclooctadecane, etc. can be cited.

[0111] The aromatic polyamine compound refers to a polyamine compound having an aromatic ring in its molecular structure. As the aromatic polyamine compound, for example, bis(cyanoethyl)diethylenetriamine, o-phenylenediamine, m-phenylenediamine (MXDA), p-phenylenediamine, phenylenediamine, naphthalenediamine, 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, polytetramethylene oxide-di-p-aminobenzoate (polytetramethylene glycol bis-p-aminobenzoate), etc. can be cited.

[0112] In one embodiment, the polyamine compound may include an aspartic acid ester amine represented by the following formula (I).

[0113]

[0114] In formula (I),

[0115] R 1 represents one selected from divalent C 1-80 hydrocarbon groups,

[0116] R 2 independently represent C 1-20 hydrocarbon groups.

[0117] As the polyamine compound, one kind can be used alone, or two or more kinds can be used in combination.

[0118] 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; aromatic polyisocyanates such as 1,4-toluene diisocyanate, 1,6-toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, m-xylylene diisocyanate, naphthalene diisocyanate, and 3,3'-dimethyl-4,4'-biphenyl diisocyanate; and polymers such as biuret bodies, isocyanurate bodies, uretdione bodies, and urethane-formate bodies of the aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate. As the polyisocyanate, one kind can be used, or two or more kinds can be used in combination.

[0119] The total equivalent ratio of the isocyanate groups of the polyisocyanate compound to the amino groups of the polyamine compound (hereinafter referred to as "NCO / NH2") is preferably 0.5 to 2.0, more preferably 0.8 to 1.2. It should be noted that the amino group used for calculating the above equivalent ratio refers to the amino group participating in the reaction with the polyisocyanate (for example, the amino group present at the molecular end). By setting the equivalent ratio within the above range, the formed coating film has advantages such as good water resistance.

[0120] The film-forming resin (A) may have hydrophilic groups such as anionic groups, cationic groups, and nonionic groups. Examples of the anionic group include a carboxyl 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 of the film-forming resin (A).

[0121] 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.

[0122] 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.

[0123] When the film-forming resin (A) has a cationic group, the amine 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.

[0124] The film-forming resin (A) may also have a hydroxyl group. When the film-forming resin (A) has a hydroxyl group, the hydroxyl value of the film-forming resin (A) is preferably 5 mgKOH / g or more and 35 mgKOH / g or less, more preferably 7 mgKOH / g or more and 30 mgKOH / g or less, and further preferably 10 mgKOH / g or more and 25 mgKOH / g or less.

[0125] Both the acid value and the hydroxyl value are based on the solid content and can be measured according to JIS K0070:1999. In addition, the amine value is based on the solid content and can be measured according to JIS K 7237.

[0126] The film-forming resin (A) may be a resin that can be dissolved in the organic solvents described later, or a water-based resin. Examples of the water-based resin include a water-soluble resin that can be dissolved in an aqueous medium; a water-dispersible resin such as a colloidal dispersion type or an emulsion type (emulsion polymerization type, forced emulsification type) that can be dispersed in an aqueous medium.

[0127] The weight-average molecular weight of the film-forming resin (A) can be, for example, 2000 or more and 10000000 or less, 10000 or more and 2000000 or less, or 50000 or more and 2000000 or less.

[0128] Regarding the weight-average molecular weight of the film-forming resin (A), in the case of the emulsion type water-dispersible resin, it can be, for example, 50000 or more and 10000000 or less, 100000 or more and 2000000 or less, or 150000 or more and 500000 or less.

[0129] In the case of a resin that can be dissolved in an aqueous medium or an organic solvent, it can be, for example, 2000 or more and 100000 or less, 10000 or more and 80000 or less, or 50000 or more and 80000 or less.

[0130] It should be noted that in this specification, the weight-average molecular weight is a value obtained by converting the measured value based on gel permeation chromatography to polystyrene.

[0131] In 100% by mass of the solid components of the coating composition, 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 still more preferably 30% by mass or more and 75% by mass or less.

[0132] In this specification, the solid components of the coating composition refer to the part obtained by removing the solvent (D) described below from all the components of the coating composition.

[0133] In the coating composition, within the range that does not affect the physical properties of the formed coating film, in addition to the film-forming resin (A), a thermoplastic resin can also be used. Examples of the thermoplastic resin include chlorinated olefin resins such as chlorinated polyethylene and chlorinated polypropylene; homopolymers or copolymers having monomer components such as vinyl chloride, vinyl acetate, and vinylidene chloride; cellulose resins; acetal resins; alkyd resins; chlorinated rubber resins; modified polypropylene resins (such as acid anhydride-modified polypropylene resins); fluororesins (for example, vinylidene fluoride resins, vinyl fluoride resins, copolymers of fluorinated olefins and vinyl ethers, copolymers of fluorinated olefins and vinyl esters), etc. The thermoplastic resin can be used singly or two or more kinds can be used in combination. By using the thermoplastic resin in combination, it is easy to adjust the physical properties of the formed coating film according to the purpose.

[0134] [Coloring Pigment (B)]

[0135] The coloring pigment (B) is a pigment having colors such as chromatic colors and achromatic colors, 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, still more preferably 20% or more, and may also 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.

[0136] In this specification, the near-infrared reflectance refers to the arithmetic mean of the spectral reflectance measured according to JIS K 5602:2008 in the wavelength range of 800 - 2500 nm. The spectral reflectance can be measured using a spectrophotometer.

[0137] In this specification, regarding the near-infrared reflectance of a pigment, a coating film containing the pigment can be formed and measured as the reflectance of the coating film. Specifically, the pigment, resin, and solvent described in Measurement Example 1 of the near-infrared reflectance and spectral reflectance of the pigment to be described later are mixed so that the pigment mass concentration (also referred to as PWC) represented by the following formula is 3 to 50% by mass. After dispersing for 60 minutes at a rotation speed of 1800 rpm using a disperser to prepare a dispersion, a black-and-white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) is used as the substrate, and an 8-mil doctor blade is used to coat it so that the thickness after drying is approximately 50 μm, and then dried at 60°C for 20 minutes to form a dried coating film. According to JIS K 5602:2008, using a spectrophotometer, the spectral reflectance of the white part of the substrate of the dried coating film is measured in the wavelength range of 800 to 2500 nm, and the arithmetic mean value thereof is used as the near-infrared reflectance of the pigment. In addition, the spectral reflectances at wavelengths 905 nm and 1550 nm to be described later can also be measured according to the method for measuring the spectral reflectance. As the spectrophotometer, for example, a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600, etc.) can be used for measurement.

[0138] Pigment mass concentration (PWC: mass%) = (solid content of pigment) / (solid content of pigment + solid content of resin) × 100

[0139] In this specification, the solid content of the resin refers to the total solid content of the film-forming resin (A) and the crosslinking agent (C) to be described later used as required, and can be determined by measuring the heating residue (the mass of the residue after heating at 105°C for 60 minutes) according to JIS K5601-1-2 (2008).

[0140] In addition, when measuring the near-infrared reflectance and spectral reflectance, the pigment mass concentration of each pigment is: above the concentration at which the white and black of the substrate become non-transmissive when forming a dried coating film on the black-and-white hiding power test paper. In this specification, regarding the pigment mass concentration of each pigment, the organic red pigment is 25% by mass, the inorganic red pigment is 30% by mass, the organic yellow pigment is 25% by mass, the inorganic yellow pigment is 30% by mass, the blue pigment is 20% by mass, the white pigment is 45% by mass, the organic black pigment is 3% by mass, and the inorganic black pigment is 50% by mass.

[0141] The pigment (B1) preferably contains pigments selected from colored pigments and achromatic pigments. Among the colored pigments, pigments with a chroma exceeding 0 are all included. For example, red-based pigments, green-based pigments, blue-based pigments, yellow-based pigments, etc. can be cited. It preferably contains one or more selected from red-based pigments, blue-based pigments, and yellow-based pigments, and more preferably contains one or more selected from red-based pigments, blue-based pigments, and yellow-based pigments.

[0142] In addition, as the pigment (B1), organic pigments and / or inorganic pigments can be used. The organic pigments tend to have high chroma or high near-infrared reflectance, and the inorganic pigments tend to have high weather resistance.

[0143] In the total 100% by mass of the pigment (B1), the content rate of the organic pigment can be 0% by mass or more and 100% by mass or less, can be 0.3% by mass or more and 70% by mass or less, can be 0.5% by mass or more and 15% by mass or less, can be 0.5% by mass or more and 8% by mass or less.

[0144] In the total 100% by mass of the pigment (B1), the content rate of the inorganic pigment can be 0% by mass or more and 100% by mass or less, can be 5% by mass or more and 99% by mass or less, can be 10% by mass or more and 50% by mass or less, can be 10% by mass or more and 20% by mass or less.

[0145] The near-infrared reflectance of the red-based pigment as the pigment (B1) is preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and still further preferably 55% or more. For example, it is also allowed to be 80% or less, and further 70% or less.

[0146] The spectral reflectance of the red-based pigment at a wavelength of 905 nm and / or 1550 nm is preferably 20% or more, more preferably 25% or more, further preferably 30% or more, and still further preferably 35% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0147] As the red-based pigment, organic pigments and / or inorganic pigments can be used. The content rate of the organic pigment in the red-based pigment can be 0% by mass, can be 1% by mass or more and 100% by mass or less, can be 20% by mass or more and 50% by mass or less.

[0148] The near-infrared reflectance of the organic red-based pigment is preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and still further preferably 55% or more. For example, it is also allowed to be 80% or less, and further 70% or less.

[0149] The spectral reflectance of the organic red pigment at a wavelength of 905 nm and / or 1550 nm is preferably 40% or more, more preferably 50% or more, further preferably 55% or more, and still further preferably 60% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0150] The near-infrared reflectance of the inorganic red pigment is preferably 40% or more, more preferably 45% or more. For example, it is also allowed to be 80% or less, and further 70% or less.

[0151] The spectral reflectance of the inorganic red pigment at a wavelength of 905 nm and / or 1550 nm is preferably 20% or more, more preferably 30% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0152] As the red pigment of the pigment (B1), for example, as the organic red pigment, Fastogen Super Magenta RH, Fastogen Red 7100Y, Fastogen Super Red 500RG, Fastogen Super Red ATY, Fastogen Super Blue Violet RVS, Rubicron Red 400RG, Rubicron Red 500RG (all manufactured by DIC Corporation), CINILEX DPP RED SR1C (manufactured by CINIC Chemicals) can be cited. As the inorganic red pigment, Toda Color 120ED (manufactured by Toda Kogyo Corporation), BAYFERROX 130M (manufactured by LANXESS Corporation), etc. can be cited.

[0153] The near-infrared reflectance of the blue pigment of the pigment (B1) is preferably 40% or more, more preferably 45% or more. For example, it is also allowed to be 80% or less, and further 70% or less.

[0154] The spectral reflectance of the blue pigment at a wavelength of 905 nm and / or 1550 nm is preferably 30% or more, more preferably 35% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0155] As the blue pigment, for example, DAIPYROXIDE color blue9453 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Fastogen Blue 9453, Fastogen Blue RS, Fastogen Blue 5380, FastogenSuper Blue 6070S (all manufactured by DIC Corporation), phthalocyanine blue 5240KB, phthalocyanine blue 5050 (both manufactured by Dainichi Seika Kogyo Co., Ltd.), HELIOGEN BLUE L7460 (manufactured by BASF Corporation), DAIPYROXIDE color green 9310 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Fastogen Green 2YK, Fastogen Green MY (both manufactured by DIC Corporation), Lionol Green6YKP-N (manufactured by TOYOCOLOR Co., Ltd.), etc. can be cited.

[0156] The near-infrared reflectance of the yellow pigment is preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and still further preferably 55% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0157] The spectral reflectance of the yellow pigment at a wavelength of 905 nm and / or 1550 nm is preferably 15% or more, more preferably 20% or more, further preferably 25% or more, and still further preferably 30% or more. For example, it is also allowed to be 95% or less, and further 90% or less.

[0158] As the yellow pigment, an organic pigment and / or an inorganic pigment can be used. The content rate of the organic pigment in the yellow pigment can be 0% by mass, can be 1% by mass or more, and can be 10% by mass or more. Additionally, it can be 50% by mass or less, and the upper limit is 100% by mass.

[0159] The near-infrared reflectance of the organic yellow pigment is preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and still further preferably 55% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0160] The spectral reflectance of the organic yellow pigment at a wavelength of 905 nm and / or 1550 nm is preferably 40% or more, more preferably 45% or more, further preferably 50% or more, and still further preferably 550 nm or more. For example, it is also allowed to be 95% or less, and further 90% or less.

[0161] The near-infrared reflectance of the inorganic yellow pigment is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, and even more preferably 55% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0162] The spectral reflectance of the inorganic yellow pigment at a wavelength of 905 nm and / or 1550 nm is preferably 20% or more, more preferably 25% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0163] Examples of the yellow pigment include, as organic yellow pigments, Symuler Fast Yellow 4192 (manufactured by DIC Corporation), HOSTAPERM YELLOW H3G (manufactured by Clariant Japan), etc. Examples of inorganic yellow pigments include Sicopal Yellow L-1110, Sicopal Yellow L-1100 (both manufactured by BASF), TAROX synthetic iron oxide YM1100 (manufactured by Titan Kogyo, Ltd.), etc.

[0164] The colored pigment of the pigment (B1) preferably contains a red pigment, a blue pigment, and a yellow pigment. Examples include pigments obtained by mixing Symuler Fast Yellow 4192 (manufactured by DIC Corporation) as the yellow pigment, Fastogen Red 7100Y (manufactured by DIC Corporation) as the red pigment, and Lionol Blue FG7980 (manufactured by TOYOCOLOR) as the blue pigment.

[0165] The total content rate of the red pigment, blue pigment, and yellow pigment is, for example, 20% by mass or more, preferably 30% by mass or more in the colored pigment, and the upper limit is 100% by mass.

[0166] The content rate of the colored pigment in the pigment (B1) can be, for example, 0% by mass or more, 1% by mass or more, 5% by mass or more. Additionally, for example, it can be 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, 18% by mass or less.

[0167] In the achromatic pigment, pigments with a chroma of 0 are all included. Examples of the achromatic pigment include white pigments, gray pigments, and black pigments, including white pigments and black pigments.

[0168] The near-infrared reflectance of the white pigment as the pigment (B1) is preferably 60% or more, more preferably 65% or more, still more preferably 70% or more, and still further preferably 75% by mass or more. For example, it may also be 99% or less, and further 90% or less.

[0169] Examples of the white pigment include TIPAQUE CR-97, TIPAQUE CR-95 (both manufactured by Ishihara Sangyo Co., Ltd.), Ti-Pure R-902 (manufactured by DuPont) and the like, which are titanium oxides.

[0170] The spectral reflectance of the white pigment at a wavelength of 905 nm and / or 1550 nm is preferably 60% or more, more preferably 65% or more, still more preferably 70% or more, and still further preferably 75% by mass or more. For example, it may also be 99% or less, and further 90% or less.

[0171] 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. In addition, it is 100% by mass or less, may be 99% by mass or less, or 90% by mass or less. For example, it may be 60% by mass or less, 55% by mass or less, or 50% by mass or less.

[0172] The near-infrared reflectance of the black pigment as the pigment (B1) is preferably 5% or more, more preferably 8% or more, still more preferably 10% or more, and still further preferably 15% or more. For example, it may also be 90% or less, and further 85% or less.

[0173] The spectral reflectance of the black pigment at a wavelength of 905 nm and / or 1550 nm is preferably 5% or more, more preferably 8% or more, still more preferably 10% or more, and still further preferably 15% or more. For example, it may also be 90% or less, and further 85% or less.

[0174] As the black pigment, an organic pigment and / or an inorganic pigment can be used. The content of the organic pigment in the black pigment may be 0% by mass, 1% by mass or more, or 20% by mass or more. In addition, it may be 50% by mass or less, and the upper limit is 100% by mass.

[0175] The near-infrared reflectance of the organic black pigment is preferably 20% or more, more preferably 30% or more, still more preferably 35% or more, and still further preferably 40% or more. For example, it may also be 80% or less, and further 70% or less.

[0176] The spectral reflectance of the organic black pigment at a wavelength of 905 nm and / or 1550 nm is preferably 40% or more, more preferably 50% or more, still more preferably 55% or more, and even more preferably 60% or more. For example, it is also allowed to be 90% or less, and further 85% or less.

[0177] The near-infrared reflectance of the inorganic black pigment is preferably 30% or more, more preferably 40% or more. For example, it is also allowed to be 80% or less, and further 70% or less.

[0178] The spectral reflectance of the inorganic black pigment at a wavelength of 905 nm and / or 1550 nm is preferably 5% or more, more preferably 10% or more. For example, it is also allowed to be 85% or less, and further 80% or less.

[0179] As the black pigment, for example, as the inorganic black pigment, DAIPYROXIDE colorblack 9590, DAIPYROXIDE color brown 9290, DAIPYROXIDE color brown 9211 (all manufactured by Dainichi Seika Kogyo Co., Ltd.), Black 411 (manufactured by The Shepherd Color Company), Black 6350 (Asahi Kasei Corporation) can be cited. As the organic black pigment, CHROMOFINE Black A-1103 (manufactured by Dainichi Seika Kogyo Co., Ltd.), Fastogen Super Black MX (manufactured by DIC Corporation), PALIOGEN BLACK S0084, PALIOTOL BLACK L0080 (all manufactured by BASF), Hostaperm Brown HFR-01 (manufactured by Clariant Japan) etc. can be cited.

[0180] The content rate of the black pigment in the pigment (B1) can be 0 mass% or more, can be 1 mass% or more, and can be 5 mass% or more. In addition, for example, it can be 50 mass% or less, can be 45 mass% or less, and can be 40 mass% or less.

[0181] The total content rate of the white pigment and the black pigment in the achromatic pigment is, for example, 50 mass% or more, preferably 60 mass% or more, and the upper limit is 100 mass%.

[0182] With respect to 100 parts by mass of the colored pigment, the content of the achromatic pigment may be 0 parts by mass or more, may be 10 parts by mass or more, and may be 50 parts by mass or more. Further, for example, it may be 20,000 parts by mass or less, may be 10,000 parts by mass or less, may be 5,000 parts by mass or less, and may be 2,500 parts by mass or less.

[0183] As the pigment (B1), 1 type may be used, or 2 or more types may be used in combination.

[0184] In one embodiment, the pigment (B1) contains at least 1 type selected from white pigments having a near-infrared reflectance of 60% or more, colored pigments having a near-infrared reflectance of 50% or more, and black pigments having a near-infrared reflectance of 5% or more. By containing these pigments in the pigment (B1), the detection accuracy of near-infrared rays in the LiDAR technology of the obtained coating film can be improved. Preferably, even when the lightness is low, the detection accuracy of near-infrared rays in the LiDAR technology can be improved.

[0185] The pigment (B1) preferably contains at least 1 type selected from white pigments having a near-infrared reflectance of 60% or more, blue pigments having a near-infrared reflectance of 50% or more, red pigments having a near-infrared reflectance of 50% or more, yellow pigments having a near-infrared reflectance of 50% or more, and black pigments having a near-infrared reflectance of 30% or more; more preferably, it contains at least 1 type selected from white pigments having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1550 nm, blue pigments having a spectral reflectance of 40% or more at a wavelength of 905 nm and / or 1550 nm, organic red pigments having a spectral reflectance of 50% or more at a wavelength of 905 nm and / or 1550 nm, inorganic red pigments having a spectral reflectance of 20% or more at a wavelength of 905 nm and / or 1550 nm, organic yellow pigments having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1550 nm, inorganic yellow pigments having a spectral reflectance of 20% or more at a wavelength of 905 nm and / or 1550 nm, organic black pigments having a spectral reflectance of 50% or more at a wavelength of 905 nm and / or 1550 nm, and inorganic black pigments having a spectral reflectance of 15% or more at a wavelength of 905 nm and / or 1550 nm.

[0186] The total content ratio of the pigment (B1) in the coloring pigment (B) may be 20% by mass or more, may be 30% by mass or more, and may be 50% by mass or more. Further, for example, it may be 100% by mass or less, may be 98% by mass or less, and may be 95% by mass or less.

[0187] In the coloring pigment (B), a coloring pigment (b) other than the pigment (B1) may be contained within a range that does not affect the near-infrared reflectance and spectral reflectance of the coating film obtained from the coating composition. Among the compounds classified as pigments by the Color Index, compounds other than the pigment (B1) can be used as the coloring pigment (b). As the coloring pigment (b), for example, organic black pigments etc. can be cited, and for example, carbon black etc. can be cited. The content rate (pigment mass concentration) of the coloring pigment (b) in the coloring pigment (B) can be 1% by mass or less, can be 0.5% by mass or less, and can be 0.1% by mass or less.

[0188] The average primary particle diameter (D50) of the coloring pigment (B) can preferably be 1 nm or more and 500 nm or less, and more preferably be 5 nm or more and 300 nm or less. The average primary particle diameter (D50) of the coloring pigment (B) can be measured using a laser Doppler particle size analyzer (for example, Microtrac UPA 150 (manufactured by Nikkiso Co., Ltd.) etc.).

[0189] The content rate of the organic pigment in the total 100% by mass of the pigment (B) can be 0% by mass or more and 100% by mass or less, can be 0.3% by mass or more and 70% by mass or less, can be 0.5% by mass or more and 10% by mass or less, and can be 3% by mass or more and 8% by mass or less.

[0190] In addition, the content rate of the inorganic pigment in the total 100% by mass of the pigment (B) can be 0% by mass or more and 100% by mass or less, can be 5% by mass or more and 99% by mass or less, can be 10% by mass or more and 50% by mass or less, and can be 10% by mass or more and 20% by mass or less.

[0191] The content rate (pigment mass concentration) of the pigment (B), in the total 100% by mass of the solid components of the film-forming resin (A), the pigment (B), and the crosslinking agent (C) used as needed described later, is preferably 5% by mass or more, more preferably 8% by mass or more, further preferably 10% by mass or more, preferably 55% by mass or less, more preferably 50% by mass or less, and further preferably 45% by mass or less.

[0192] The content rate (pigment mass concentration) of the pigment (B1), in the total 100% by mass of the solid components of the film-forming resin (A), the pigment (B), and the crosslinking agent (C) used as needed described later, is preferably 3% by mass or more, more preferably 8% by mass or more, further preferably 10% by mass or more, preferably 55% by mass or less, more preferably 50% by mass or less, and further preferably 45% by mass or less.

[0193] The lightness (L* value) of the coating film obtained from the coating composition is preferably 80 or less, and can be, for example, 5 or more. Additionally, for example, it can be 70 or less, or can be 15 or more. By using the coating composition of the present invention, even when the lightness (L* value) of the coating film is low, the visibility in LiDAR technology can be maintained. It should be noted that the lightness (L* value) of the coating film may vary depending on the thickness (film thickness) of the coating film.

[0194] In this specification, the lightness of the coating film can be measured by the same method as that of the coating film containing the pigment. Specifically, the pigment, resin, and solvent described in Measurement Example 1 of the near-infrared reflectance and spectral reflectance of the pigment to be described later are mixed so that the pigment mass concentration is 3 to 50% by mass, and after being dispersed for 60 minutes at a rotation speed of 1800 rpm using a disperser to form a dispersion, a black and white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) is used as the substrate, and it is coated so that the thickness after drying is about 100 μm, and dried at 60 °C for 20 minutes to form a dried coating film. For the obtained coating film, the lightness of the white part of the substrate of the obtained dried coating film can be measured according to 3.2 of JIS K 5600-4-4 and JIS K 5600-4-5 as the lightness. The lightness can be measured, for example, using a color difference meter CM-600d (manufactured by Konica Minolta Inc.).

[0195] When the lightness of the target coating film is denoted as L*0, the relationship between L*0 and the range of the pigment mass concentration of each pigment is represented by the following formula. That is, the pigment mass concentration of each pigment can be in the range that satisfies the following formula. Additionally, L*0 can take values within the above range as the lightness of the coating film.

[0196] L*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)

[0197] Among them, (W) is the pigment mass concentration (% by mass) of the white pigment system, (IR) is the pigment mass concentration (% by mass) of the inorganic red pigment system, (OR) is the pigment mass concentration (% by mass) of the organic red pigment system, (IY) is the pigment mass concentration (% by mass) of the inorganic yellow pigment system, (OY) is the pigment mass concentration (% by mass) of the organic yellow pigment system, (OB) is the pigment mass concentration (% by mass) of the blue pigment system, (IBL) is the pigment mass concentration (% by mass) of the inorganic black pigment system, and (OBL) is the pigment mass concentration (% by mass) of the organic black pigment system.

[0198] When the near-infrared reflectance of the target coating film is denoted as X0 (%), the relationship between X0 (%) and the pigment mass concentration of each pigment is expressed by the following formula. That is, the pigment mass concentration of each pigment can be in the range that satisfies the following formula. In addition, X0 (%) can take values within the above range as the near-infrared reflectance of the coating film.

[0199] X0 = 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)

[0200] When the spectral reflectance of the target coating film at a wavelength of 905 nm is denoted as Y0 (%), the relationship with the pigment mass concentration of each pigment is expressed by the following formula. That is, the pigment mass concentration of each pigment can be in the range that satisfies the following formula. In addition, Y0 (%) can take values within the above range as the spectral reflectance of the coating film at a wavelength of 905 nm.

[0201] Y0 = 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)

[0202] When the spectral reflectance of the target coating film at a wavelength of 1550 nm is denoted as Z0 (%), the relationship between Z0 (%) and the pigment mass concentration of each pigment is expressed by the following formula. That is, the pigment mass concentration of each pigment can be in the range that satisfies the following formula. In addition, Z0 (%) can take values within the above range as the spectral reflectance of the coating film at a wavelength of 905 nm.

[0203] Z0 = 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)

[0204] The lightness of the coating film can be 80 or less. The combination of the pigment mass concentrations at this time is calculated variously by Formula (1). In this combination, through Formulas (2) to (4), the combination of the pigment concentrations that make the near-infrared reflectance, the spectral reflectance at a wavelength of 905 nm, and the spectral reflectance at a wavelength of 1550 nm above the expected value (for example, 15% or more) can be calculated.

[0205] [Crosslinking agent (C)]

[0206] In the said coating composition, in addition to the film-forming resin (A) and the pigment (B), a crosslinking agent (C) may also be contained. The crosslinking agent (C) is a compound capable of forming a crosslinked structure in the film-forming resin (A) by forming a chemical bond (chemical bonding) and / or a physical bond (physical bonding), and examples thereof include compounds having two or more groups having active hydrogen atoms such as hydroxyl groups, carboxyl groups, and amino groups in one molecule; or compounds having two or more groups capable of reacting with the groups having active hydrogen atoms in one molecule, etc. When the film-forming resin (A) has a group having an active hydrogen atom or a group capable of reacting with the group having an active hydrogen atom, it can react with the crosslinking agent (C) to form a crosslinked structure in the film-forming resin (A).

[0207] As the crosslinking agent (C), polyisocyanate compounds; blocked polyisocyanate compounds; amino resins; phenolic resins; polycarboxylic acids, etc. can be cited. One of them can be used, or two or more thereof can be used in combination.

[0208] 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-toluene diisocyanate, 2,6-toluene diisocyanate and their mixtures, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate and their mixtures, naphthalene-1,5-diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, xylylene diisocyanate, etc.; alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, etc.; aliphatic polyisocyanates such as hexamethylene diisocyanate, etc.

[0209] The blocked polyisocyanate compound (hereinafter sometimes also referred to as "BI") refers to a compound obtained by blocking the isocyanate group of the isocyanate compound with a blocking agent.

[0210] The blocking agent only needs to be a compound having a compound containing an active hydrogen compound. For example, phenolic compounds such as phenol, cresol, and xylenol can be used; lactam compounds such as ε-caprolactam, δ-valerolactam, and γ-butyrolactam; aliphatic alcohol compounds such as methanol, ethanol, n-butanol, isobutanol, or tert-butanol; 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, acetaldehyde oxime, acetone oxime, methyl ethyl ketoxime, diacetyl monoxime, benzophenone oxime, and cyclohexanone oxime; active methylene compounds such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, and acetylacetone, etc. By mixing the polyisocyanate compound and the blocking agent, the free isocyanate group of the polyisocyanate compound can be blocked.

[0211] The amino resin refers to a resin obtained by addition polymerization of an aldehyde to a compound having an amino group. The amino resin has excellent crosslinking reactivity with the film-forming resin (A), and particularly has excellent crosslinking reactivity with the film-forming resin (A) even without a catalyst, and thus is preferred.

[0212] Examples of the amino resin include melamine resin, urea resin, etc., and melamine resin is preferred.

[0213] The melamine resin refers to a thermosetting resin synthesized from melamine and an aldehyde. In the melamine resin, there are a triazine nucleus and three reactive functional groups (-NX1X2) per one triazine nucleus. Examples of the melamine resin include a fully alkylated type containing only -N(CH2OR)2 [R represents an alkyl group having 1 or more and 8 or less carbon atoms, the same applies hereinafter] as a reactive functional group; a hydroxymethyl type containing -N(CH2OR)(CH2OH) as a reactive functional group; an imino type containing -N(CH2OR)(H) as a reactive functional group; and a hydroxymethyl / imino type containing -N(CH2OR)(CH2OH) and -N(CH2OR)(H) or containing -N(CH2OH)(H) as a reactive functional group. As the melamine resin, one type can be used, or two or more types can be used in combination. As the crosslinking agent (C), the melamine resin and the polyisocyanate compound can be used in combination. In addition, if necessary, a metal catalyst such as a tin compound or a titanium compound can also be used.

[0214] Examples of the phenolic compound include glycidyl ether type resins such as condensation products of bisphenol A and epichlorohydrin, and condensation products of bisphenol F and epichlorohydrin; alicyclic epoxy resins, linear aliphatic epoxy resins, bromine-containing epoxy resins, phenol novolak type epoxy resins, cresol novolak type epoxy resins, etc.

[0215] The polycarboxylic acid refers to a compound having two or more carboxyl groups in one molecule. Examples of the polycarboxylic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclohexane-1,4-dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid, 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, dodecenyl succinic acid; hydroxy acids of lactose; acid anhydrides of the aromatic polycarboxylic acids, the alicyclic polycarboxylic acids, and the aliphatic polycarboxylic acids.

[0216] In one embodiment, the crosslinking agent (C) is preferably selected from one or more of polyisocyanate compounds, blocked polyisocyanate compounds, and amino resins.

[0217] The content of the crosslinking agent (C) can be, for example, 3 parts by mass or more, 7 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more in a total of 100 parts by mass of the film-forming resin (A) and the crosslinking agent (C). Additionally, for example, it can be 50 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, 30 parts by mass or less.

[0218] The total content ratio of the film-forming resin (A) and the crosslinking agent (C) in the solid components of the coating composition is preferably 30% by mass or more, more preferably 40% by mass or more, further preferably 45% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, and further preferably 85% by mass or less.

[0219] [Solvent (D)]

[0220] The coating composition may further contain a solvent (D). The solvent preferably contains an aqueous medium (D1) and / or an organic solvent (D2).

[0221] Examples of the aqueous medium (D1) include water, hydrophilic solvents, and mixtures of water and hydrophilic solvents.

[0222] Examples of the hydrophilic solvent include glycol solvents such as ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, 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. By using such hydrophilic solvents, the coating composition obtained has the advantage of good wettability with the substrate.

[0223] Examples of the organic solvent (D2) include ether solvents such as dibutyl ether 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., Ltd.); hydrocarbon solvents such as pentane, isopentane, hexane, isohexane, and cyclohexane; solvent naphtha and mineral spirits. They can be used singly or in combination of two or more.

[0224] The coating composition may be an aqueous coating composition mainly containing an aqueous medium (D1) as a solvent (D), or a solvent-based coating composition mainly containing an organic solvent (D2) as a 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.

[0225] The content of the solvent (D) in the coating composition is preferably 0% by mass or more, more preferably 10% by mass or more, further preferably 30% by mass or more, preferably 70% by mass or less, and more preferably 60% by mass or less.

[0226] The coating composition may be an aqueous coating, an organic solvent-based coating, or a solvent-free coating such as a powder coating.

[0227] [Aggregate (E)]

[0228] The coating composition includes an aggregate (E). In the present disclosure, the aggregate (E) is an amorphous granular material, and includes an aggregate (E1) having a near-infrared reflectance of 5% or more. However, the aggregate (E) is different from the pigment (B).

[0229] Examples of the material constituting the aggregate (E1) include fine particles such as SiO2, TiO2, Al2O3, Cr2O3, ZrO2, FeO, Fe2O3, CaP, CrO, Al2O3·SiO2, 3Al2O3·2SiO2, zirconium silicate, ceramic beads, and mixtures thereof. In addition, the term "fine particle" means a particle, a sphere, or a hollow sphere.

[0230] The near-infrared reflectance of the aggregate (E1) is preferably 5% or more, more preferably 10% or more, further preferably 20% or more, and may be, for example, 99% or less, and further 90% or less. Thus, even when reflected and scattered on the surface where near-infrared rays are obtained, good retroreflectivity can be obtained when the incident angle is a high angle.

[0231] The near-infrared reflectance of the aggregate (E) can be measured by the following method.

[0232] [Method for Measuring Near-Infrared Reflectance]

[0233] Cover the adhesive surface of a black adhesive sheet that is 15 cm long and 7 cm wide with the aggregate (E). Stand the sheet against a wall and repeatedly perform the operation of brushing off the aggregate (E) that does not come into contact with the adhesive surface until the black adhesive surface cannot be visually confirmed and the aggregate that naturally falls off from the standing sheet disappears. Next, for the adhesive surface covered with the aggregate (E), use a spectrophotometer to measure the spectral reflectance in the wavelength range of 800 to 2500 nm according to JIS K5602:2008, and take the value obtained by arithmetically averaging the obtained spectral reflectances as the near-infrared reflectance of the aggregate (E). In addition, the spectral reflectances at wavelengths of 905 nm and 1550 nm can also be measured according to the method for measuring the spectral reflectance. As the spectrophotometer, for example, a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600, etc.) can be used for measurement.

[0234] The spectral reflectance of the aggregate (E1) at wavelengths of 905 nm and / or 1550 nm is preferably 5% or more, more preferably 10% or more, and further preferably 20% or more. For example, it is also allowed to be 99% or less, and further 90% or less.

[0235] The average particle size of the aggregate (E1) can preferably be 50 μm or more, more preferably 50 μm or more and 3000 μm or less, further preferably 70 μm or more and 2500 μm or less, further preferably 100 μm or more and 2000 μm or less, further preferably 150 μm or more and 2000 μm or less, and even more preferably 200 μm or more and 2000 μm or less.

[0236] It should be noted that the average particle size of the aggregate (E) refers to the volume average particle size (D50), and it can be measured using a sieving method (such as JIS test sieves (manufactured by Iida Seisakusho), etc.). As the sieve, for example, a sieve with a pore size of 106 μm or more and 3360 μm or less can be used. Specifically, sieves with pore sizes of 150 μm, 180 μm, 212 μm, 250 μm, 300 μm, 425 μm, 500 μm, 710 μm, 1000 μm, and 1700 μm can be used.

[0237] It should be noted that in the present disclosure, the average particle size of the aggregate (E) means: using three or more sieves with different pore sizes, setting the average particle size of the aggregate that has passed through all the sieves to half of the pore size of the sieve with the smallest pore size, setting the average particle size of the aggregate (residual part) that has not passed through the sieve with the largest pore size to the pore size of the sieve with the largest pore size, setting the average particle size of the residual part on the other sieves to the average of the pore size of the sieve and the pore size of the sieve one level smaller than the pore size of the sieve, and taking the weighted average value of the average value and the amount (sieve residue: mass%) of the residual part on each sieve.

[0238] As the aggregate (E1), commercially available products can also be used. Examples of such commercially available products include Cerasan HR-C, Cerasan HR-S, Cerasan HR-B (manufactured by American Kogyo Co., Ltd.), White Silica (manufactured by Yamamori Tsuchimoto Mining Co., Ltd.), etc.

[0239] The content ratio of the aggregate (E1) contained in the aggregate (E) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and preferably 100% by mass or less in 100% by mass in total of the aggregate (E).

[0240] In the aggregate (E), in addition to the aggregate (E1), other aggregates (E2) may be contained. Examples of such aggregate (E2) include aggregates with a near-infrared reflectance of less than 5%. Examples of the material constituting the aggregate (E2) are the same as the material constituting the aggregate (E1).

[0241] The content ratio 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, still more preferably 30% by mass or more and 60% by mass or less in 100% by mass in total of the solid components of the film-forming resin (A), the pigment (B), the aggregate (E), and the crosslinking agent (C) used as needed. In the present invention, the content ratio of the aggregate (E) in 100% by mass in total of the solid components of the film-forming resin (A), the pigment (B), the aggregate (E), and the crosslinking agent (C) used as needed is also referred to as the mass concentration of the aggregate (E).

[0242] The coating composition may further contain other additives. Examples of such other additives include surface modifiers; extender pigments; colorants such as dyes; waxes; brightening pigments; fillers (different from the aggregate (E), particularly including particulate fillers, etc.); ultraviolet absorbers (benzophenone-based ultraviolet absorbers, etc.); antioxidants (phenolic, thioether-based, hindered amine-based antioxidants, etc.); plasticizers; coupling agents (silane-based, titanium-based, zirconium-based coupling agents, etc.); anti-sagging agents; thickeners; pigment dispersants; pigment wetting agents; leveling agents; anti-segregation agents; anti-settling agents; defoamers; antifreezing agents; emulsifiers; preservatives; mildew-proof agents; antibacterial agents; stabilizers, etc. These additives may be used singly or in combination of two or more.

[0243] Examples of such brightening pigments include mica, aluminum foil, tin foil, gold foil, silver foil, titanium gold foil, stainless steel foil, metal foils such as nickel / copper, etc.

[0244] The coating composition can be prepared by dissolving or dispersing the film-forming resin (A), the pigment (B), the aggregate (E), and, if necessary, the crosslinking agent (C) and other additives in the solvent (D) used as needed. In addition, the mixing order of the various materials used is not particularly limited. For example, the pigment (B) and / or the aggregate (E) and a part of the film-forming resin (A) can be premixed to form a pigment paste, and then mixed with the remaining components and other components used as needed to produce the coating composition. The coating composition of the present specification can be prepared by mixing the respective components, for example, by selecting a mixer, a disperser, a kneader, etc., such as a sand mill, a ball mill, a stirrer, a paint shaker, or a dispenser.

[0245] In the present disclosure, products in a state where the aggregate (E) is scattered on a coating film coated with a preliminary coating composition prepared using the film-forming resin (A), the pigment (B), and, if necessary, the crosslinking agent (C) and other additives, or products in a state where the aggregate (E) is scattered on the coating film and the preliminary coating composition is further coated thereon are also included within the technical scope of the coating composition.

[0246] The coating film formed from the coating composition is also included within the technical scope of the present disclosure.

[0247] The near-infrared reflectance of the coating film is preferably 15% or more, more preferably 30% or more, and still more preferably 35% or more. For example, it is also allowed to be 99% or less, and further 90% or less.

[0248] The spectral reflectance of the coating film at a wavelength of 905 nm and / or 1550 nm is preferably 20% or more, more preferably 30% or more, and still more preferably 35% or more. For example, it is also allowed to be 99% or less, and further 90% or less.

[0249] The near-infrared reflectance of the coating film and the spectral reflectance at a wavelength of 950 nm and / or 1550 nm can be measured, for example, by the same method as the method described for measuring the near-infrared reflectance of a coating film containing a pigment when measuring the near-infrared reflectance of the pigment.

[0250] The coating film for measuring the near-infrared reflectance can be formed, for example, by the following method.

[0251] The coating composition is coated on a black-and-white hiding power test paper (manufactured by Nippon Test Panel Co., Ltd.) as a substrate so that the thickness of the wet coating film is 30 μm or more and 2000 μm or less, and heated at a heating temperature of 20°C or more and 200°C or less for 10 minutes or more and 24 hours or less to obtain a dry coating film.

[0252] In the coating film obtained from the coating composition, the lightness (L* value) can be 80 or less, for example, 70 or less. Additionally, for example, it can be 5 or more, or 15 or more.

[0253] The lightness of the coating film can be measured using a color difference meter according to 3.2 of JIS K 5600-4-4 and JIS K 5600-4-5, for example. As the color difference meter, for example, CM-600d (manufactured by Konica Minolta Inc.) can be used for measurement.

[0254] In this specification, the coating film for measuring lightness, near-infrared reflectance, and spectral reflectance can be formed by the following method, for example.

[0255] The coating composition is applied onto an asphalt felt sheet 430 (manufactured by Shizuoka Asphalt Industry Co., Ltd.) as a substrate, such that the thickness of the wet coating film is 30 μm or more and 2000 μm or less, and it is heated at a heating temperature of 20°C or more and 200°C or less for 10 minutes or more and 24 hours or less to obtain a dry coating film. The part for measuring the lightness (L* value) can be the lightness of the white part of the substrate of the obtained dry coating film. It should be noted that "the thickness of the wet coating film or the thickness after drying of the wet coating film (thickness of the dry coating film) is 30 μm or more and 2000 μm or less" means that in the wet coating film or the dry coating film, the minimum value of the film thickness is 30 μm or more, and the maximum value of the film thickness is 2000 μm or less.

[0256] Since the wavelength range of near-infrared light is close to the visible light region, a coating composition with a high near-infrared reflectance tends to have a high reflectance of visible light and an increased lightness. Generally, when the lightness (L* value) is less than 80, the near-infrared reflectance tends to decrease, and the LiDAR visibility tends to decrease. However, the coating composition, by having the above-described configuration, can easily increase the near-infrared reflectance while reducing the lightness.

[0257] The lightness of the coating film measured by the above method can be 90 or less, for example, or 80 or less. Additionally, it can be 3 or more, or 5 or more.

[0258] 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, further preferably 30 μm or more and 250 μm or less, and still further preferably 60 μm or more and 200 μm or less. In addition, the root mean square height (Sq) of the coating film is preferably 10 μm or more, more preferably 20 μm or more, further preferably 20 μm or more and 400 μm or less, then preferably 30 μm or more and 350 μm or less, and still more preferably 70 μm or more and 300 μm or less. Since the arithmetic mean height (Sa) or the root mean square height (Sq) of the coating is within the above range, the LiDAR visibility can be good.

[0259] The surface roughness of the coating film can be measured according to ISO 25178. Based on the surface roughness measurement, the arithmetic mean height and the root mean square height are calculated respectively as the arithmetic mean height (Sa) and the root mean square height (Sq) of the coating film. The surface roughness can be measured, for example, using a laser microscope (such as the laser microscope VK-X200 manufactured by KEYENCE Corporation).

[0260] In the present disclosure, the coating film for measuring the arithmetic mean height and the root mean square height can be formed, for example, by the following method.

[0261] The coating composition is applied onto an asphalt felt sheet 430 (manufactured by Shizuoka Asphalt Industry Co., Ltd.) as a substrate so that the thickness of the wet coating film is 30 μm or more and 2000 μm or less, and heated at a heating temperature of 20°C or more and 200°C or less for 10 minutes or more and 24 hours or less to obtain a dried coating film.

[0262] It should be noted that the arithmetic mean height (also referred to as "Sa") is a parameter indicating the surface roughness of the coating film, representing the average of the absolute values of the height differences of each point with respect to the average plane of the coating film surface. When Sa is small, it means that the coating film surface is flatter, and when Sa is large, it means that the coating film surface has larger irregularities. In addition, 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 coating film surface.

[0263] The thickness of the wet coating film can be preferably 10 to 3000 μm, more preferably 30 to 2500 μm, and further preferably 30 to 2000 μm. In addition, the thickness after drying of the wet coating film (the thickness of the dry coating film) is preferably 10 to 3000 μm, more preferably 10 to 2000 μm, and further preferably 10 to 1500 μm.

[0264] The method of forming a coating film using the coating composition of the present disclosure is also included within the technical scope of the present disclosure.

[0265] The first coating film manufacturing method of the present disclosure includes:

[0266] Coating the coating composition on a road surface to obtain a coated film, and

[0267] Drying the coated film to obtain a coating film for a detection object using near-infrared light sensing.

[0268] The coated film is preferably coated in such a manner that the thickness of the wet coated film is preferably 10 μm or more and 3000 μm or less, more preferably 20 μm or more and 2500 μm or less, and still more preferably 30 μm or more and 2000 μm or less.

[0269] The coating can be carried out by coating methods such as spray coating method, bar coater coating method, air knife coating method, gravure coating method, brush coating method, air gun coating method, air electrostatic gun coating method, dip coating method, etc.

[0270] In addition, the drying temperature when drying the coated film can be preferably 20°C or more and 200°C or less, more preferably 70°C or more and 180°C or less, and still more preferably 80 - 140°C, and the drying time can be preferably 10 minutes or more and 24 hours or less, more preferably 10 - 60 minutes, and still more preferably 15 - 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. can be adopted.

[0271] The second coating film manufacturing method of the present disclosure includes:

[0272] Coating a second coating composition on a road surface to obtain a second coated film,

[0273] Spreading aggregate (E) on the second coated film, and

[0274] Drying the second coated film to obtain a coating film for a detection object using near-infrared light sensing,

[0275] The second coating composition contains the film-forming resin (A) and the coloring pigment (B),

[0276] The coloring pigment (B) contains at least one selected from the following: when the reflectance in the wavelength range of 800 - 2500 nm is set as the near-infrared reflectance, a white pigment with a near-infrared reflectance of 60% or more, a colored pigment with a near-infrared reflectance of 50% or more, and a black pigment with a near-infrared reflectance of 30% or more,

[0277] The aggregate (E) contains aggregate (E1) with a near-infrared reflectance of 5% or more.

[0278] The product in the state of spreading aggregate (E) on the second coated film is also included in the coating composition of the present disclosure.

[0279] The second coating composition contains the film-forming resin (A) and the coloring pigment (B), and may further contain the crosslinking agent (C), the solvent (D), and the other additives. Additionally, the second coating composition may also contain the aggregate (E). The types and amounts of the respective components may be based on the types and amounts of the components that can be contained in the coating composition of the present disclosure described above.

[0280] The second coating film is preferably applied in such a manner that the thickness of the wet coating film is preferably 10 μm or more and 3000 μm or less, more preferably 20 μm or more and 2500 μm or less, and further preferably 30 μm or more and 2000 μm or less.

[0281] The coating can be carried out, for example, by coating methods such as spray coating method, bar coater coating method, air knife coating method, gravure coating method, brush coating method, air gun coating method, air electrostatic gun coating method, dip coating method, etc.

[0282] In addition, the drying temperature when drying the second coating film can be preferably 20°C or more and 200°C or less, more preferably 70°C or more and 180°C or less, and further preferably 80 to 140°C, and the drying time can be preferably 10 minutes or more and 24 hours or less, more preferably 10 to 60 minutes, and further preferably 15 to 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. can be adopted.

[0283] In the second film-forming method, after scattering the aggregate (E) and before drying the second coating film, the second coating film can be further coated to form a third coating film. That is, the third film manufacturing method of the present disclosure includes:

[0284] Coating a third coating composition on the road surface to obtain a third coating film,

[0285] Scattering the aggregate (E) on the third coating film, and

[0286] Coating a fourth coating composition on the third coating film on which the aggregate (E) is scattered to obtain a fourth coating film,

[0287] Drying the third coating film and the fourth coating film to obtain a coating film for a detection object using near-infrared light sensing,

[0288] The third coating composition contains the film-forming resin (A) and the coloring pigment (B),

[0289] The fourth coating composition contains the film-forming resin (A) and the coloring pigment (B),

[0290] The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance.

[0291] The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

[0292] A product in a state where the aggregate (E) is scattered on the third coating film and then the fourth coating film is formed is also included in the coating composition of the present disclosure.

[0293] The third or fourth coating composition contains the film-forming resin (A) and the coloring pigment (B), and may further contain the crosslinking agent (C), the solvent (D), and the other additives. In addition, the second coating composition may further contain the aggregate (E). The types and amounts of the respective components may be based on the types and amounts of the respective components that can be contained in the coating composition of the present disclosure described above.

[0294] The third coating composition and the fourth coating composition may be the same or different. For example, the near-infrared reflectance of the coating film formed by the fourth coating composition may also be higher than that of the coating film formed by the third coating composition. In addition, the pigment mass concentration of the pigment (B1) in the fourth coating composition may also be higher than the pigment mass concentration of the pigment (B1) in the third coating composition.

[0295] The third and fourth coating films are preferably applied in such a manner that the thickness of the wet coating film is preferably 10 μm or more and 3000 μm or less, more preferably 20 μm or more and 2500 μm or less, and further preferably 30 μm or more and 2000 μm or less.

[0296] The coating can be carried out, for example, by coating methods such as spray coating method, bar coater coating method, air knife coating method, gravure coating method, brush coating method, air gun coating method, air electrostatic gun coating method, dipping coating method, etc.

[0297] In addition, the drying temperature when drying the third and fourth coating films can be preferably 20°C or more and 200°C or less, more preferably 70°C or more and 180°C or less, and further preferably 80 to 140°C, and the drying time can be preferably 10 minutes or more and 24 hours or less, more preferably 10 to 60 minutes, and further preferably 15 to 45 minutes. As the heating means, hot air heating, infrared heating, induction heating, etc. can be adopted.

[0298] In the first to third manufacturing methods, the coating composition is applied to the road surface, but it is not limited thereto, and other objects to be coated can also be coated. Examples of the objects to be coated with the coating film include metal plates, members composed of metal plates, plastic members, inorganic material members, wooden members, and paving bodies such as road surfaces.

[0299] Examples of the metal plate include galvanized steel plates, galvanized-aluminum alloy steel plates, aluminum alloy-coated steel plates, molten zinc-aluminum-magnesium alloy-coated steel plates, stainless steel plates, cold-rolled steel plates, etc. manufactured by melting methods or electrolytic methods. In addition, metal plates such as aluminum plates (including aluminum alloy plates) can also be coating objects in addition to these steel plates or coated steel plates. The metal plate is preferably surface-treated. Specifically, it is preferred that the metal plate is subjected to chemical conversion treatment after pretreatment such as alkali degreasing treatment, hot water washing treatment, and water washing treatment. The chemical conversion treatment can be carried out by a known method, and examples thereof include non-chromate treatments such as chromate treatment and zinc phosphate treatment. As the surface treatment, it can be appropriately selected according to the steel plate used, but a treatment without heavy metals is preferred.

[0300] Examples of the plastic member include acrylic plates, polyvinyl chloride plates, polycarbonate plates, ABS plates, polyethylene terephthalate plates, polyolefin plates, etc.

[0301] Examples of the inorganic material member include ceramic building materials and glass substrates described in JIS A 5422, JIS A 5430, etc., and examples thereof include 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, lightweight aerated concrete boards, etc.

[0302] Examples of the wooden member include sawn timber, glued laminated timber, plywood, particle board, fiber board, modified wood, chemically treated wood, floors, etc.

[0303] Examples of the paving body such as the road surface include asphalt paving, concrete paving, brick paving, etc.

[0304] Specific examples of the object to be coated include structures and articles that can become obstacles during the automatic driving of automobiles. For example, various sold commodities, driving roads, road structures (such as paving, road markings, sidewalks, crosswalks, drainage facilities, flat intersection structures, bridges, civil engineering works, tunnels, shelters, traffic safety facilities (such as overpasses, guardrails, guard posts, fences, lighting facilities, sight guide signs, road mirrors, etc.), traffic islands, stations, parking bays, parking lots, etc.), various building structures and their internal equipment, railway structures, various protective facilities, various vehicles and their accessories, pedestrian clothing, utility poles, inner walls of each building, etc.

[0305] In addition, a sensing method using near-infrared light using the coating film is also included within the technical scope of the present invention.

[0306] For example, near-infrared rays of a specific wavelength are irradiated from a moving vehicle, reflected on a detection object, the reflected light is detected, and the distance from the vehicle to the painted object as the detection object is calculated based on the time required for reflection, thereby measuring the distance between the vehicle and the painted object. In such a sensing method (time-of-flight measurement method: ToF (Time-of-Fright)), the painted object can be a product obtained by painting the coating composition. In addition, near-infrared rays of a specific wavelength are irradiated from a moving vehicle, reflected on a detection object, the reflected light is detected, and the distance from the vehicle to the detection object is calculated based on the change in the frequency difference between the irradiated light and the reflected light, thereby measuring the distance between the vehicle and the painted object. In such a sensing method (frequency modulation continuous wave method: FMCW (Frequency Modulated Continuous Wave)), the painted object can be a product obtained by painting the coating composition.

[0307] Even when the coating composition and the coating film are formed on a road surface, a sign can be realized that can exhibit high retroreflectivity (especially retroreflectivity at a high incident angle) without being mistaken for a white line. According to such a sign, the detection accuracy of near-infrared light in LiDAR technology can be improved, preferably the detection accuracy of near-infrared light in LiDAR technology can be improved even at low brightness, especially the detection accuracy of the incident angle during long-distance recognition is envisioned, and it is useful as a coating and a coating film for a detection object for sensing using near-infrared light.

[0308] Examples

[0309] The present invention will be described more specifically by the following examples, but the present invention is not limited to these.

[0310] <Example 1 for Measuring the Near-Infrared Reflectance and Spectral Reflectance of Pigments>

[0311] Example for measuring the near-infrared reflectance of an organic red pigment and the spectral reflectance at wavelengths of 905 nm and / or 1550 nm

[0312] 21 parts by mass of (A-1) Aroset 5534-SB60 as a film-forming resin, 12.0 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent, and 17.0 parts by mass of (B21-1) CINILEX DPP RED SR1C as an organic red pigment were mixed and dispersed using an SG mill (medium: glass beads) until the maximum particle size of the coarse pigment particles was 10 μm or less. Then, 50 parts by mass of (A-1) was added and mixed using a dispenser (disper, disperser) while stirring to obtain a main agent.

[0313] 62 parts by mass of (C-1) Duranate TSA-100 as a crosslinking agent and 38 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent were mixed using a dispenser while stirring to obtain a curing agent.

[0314] The main agent and the curing agent obtained above were mixed at a mass ratio of 9:1 to obtain a coating composition (pigment mass concentration: 30 mass%). Using an 8-mil doctor blade, the obtained coating composition was applied onto a black-and-white hiding power test paper (manufactured by Nippon TestPanel Co., Ltd.) so that the dry film thickness was 50 μm, dried at 60°C for 20 minutes, and then allowed to stand at room temperature for 1 day to obtain a coating film.

[0315] For the obtained coating film, for the white base part, using a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600), the reflectance in the wavelength range of 800 to 2500 nm was measured at 2-nm wavelength intervals according to the method of JIS K5602. The arithmetic mean of the reflectances at each obtained wavelength was taken as the near-infrared reflectance of the inorganic red pigment. In addition, the near-infrared reflectances at 905 and 1550 nm were the values of the spectral reflectances at each wavelength.

[0316] For the near-infrared reflectances of other pigments, except that the type and pigment mass concentration of each pigment were set to the amounts described in Table 1, the near-infrared reflectances and spectral reflectances of each pigment were measured in the same manner as in Measurement Example 1 of the near-infrared reflectance and spectral reflectance of the said pigment.

[0317] [Table 1]

[0318]

[0319]

[0320] <Production Example 1>

[0321] Production Example of White Pigment Paste

[0322] 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., Ltd.) 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 grinder (medium: glass beads) until the maximum particle size of the coarse pigment particles was 10 μm or less. Subsequently, 37 parts by mass of (A-1) was added and mixed with stirring using a dispenser to obtain a white pigment paste (W-1).

[0323] <Production Examples 2 to 7>

[0324] The types and amounts of the film-forming resin, solvent, and pigment used were changed as described in Table 2, and apart from this, the pigment pastes of each pigment were obtained in the same manner as in Production Example 1 above.

[0325] [Table 2]

[0326]

[0327]

[0328] <Production Example of Clear Coat for PWC Adjustment>

[0329] 83 parts by mass of (A-1) Aroset 5534-SB60 (manufactured by Nippon Shokubai Co., Ltd.) as a 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 with stirring using a dispenser to obtain a clear coat for PWC adjustment (clear).

[0330] <Example 1>

[0331] 0.6 part 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 the clear coat for PWC adjustment were mixed with stirring using a dispenser to obtain a main agent (S-1).

[0332] 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., Ltd.) were mixed with stirring using a dispenser to obtain a curing agent (K-1).

[0333] <Production Example 1 of Coating Film (Test Piece)>

[0334] 162.2 parts by mass of the main agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed with a disperser while stirring, and then 54.1 parts by mass of the filler (E1-1) was added and mixed to obtain Coating Composition 1 (pigment mass concentration: 14 mass%). The obtained Coating Composition 1 was applied onto an asphalt felt 430 (70×150 mm, manufactured by Shizuoka Asphalt Industry Co., Ltd.) such that the thickness of the wet coating film was 2000 μm, dried at 60°C for 20 minutes, and then left standing at room temperature for 1 day to obtain Test Piece 1. It should be noted that the mass ratio of the main agent (S-1) to the curing agent (K-1) was 9:1.

[0335] The types and amounts of the pigment paste, PWC adjustment varnish, crosslinking agent, and solvent used were changed as described in Table 3, and other than that, each coating film (test piece) was obtained in the same manner as in Production Example 1 of the coating film (test piece).

[0336] In addition, when other materials are contained in the coating composition, the other materials are mixed with various pigment pastes and PWC adjustment varnishes when preparing the main agent, thereby preparing the main agent.

[0337] <Examples 2 to 12>

[0338] Except that the types and amounts of the respective components were changed as described in Table 4, the main agent and the curing agent were prepared in the same manner as in Example 1 to obtain test pieces. It should be noted that the total mass concentration of the aggregate (E1) in the table was replaced with the amount of the other aggregate (E2) when using the other aggregate (E2). It should be noted that in Table 4, the amounts of the respective components, pigment paste, and PWC adjustment varnish are the amounts of the respective components, pigment paste, and PWC adjustment varnish including volatile components such as solvents.

[0339] <Example 13>

[0340] 162.2 parts by mass of the main agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed with a disperser while stirring to obtain Coating Composition 13 (pigment mass concentration: 14 mass%). The obtained Coating Composition 13 was applied onto an asphalt felt 430 (manufactured by Shizuoka Asphalt Industry Co., Ltd.) to a wet film thickness of 2000 μm, and 54.1 parts by mass of the filler (E1-5) was evenly scattered on its surface visually, dried at 60°C for 20 minutes, and then left standing at room temperature for 1 day to obtain Test Piece 13. It should be noted that the mass ratio of the main agent (S-1) to the curing agent (K-1) was 9:1.

[0341] <Example 14>

[0342] 162.2 parts by mass of the main agent (S-1) and 18.2 parts by mass of the curing agent (K-1) obtained above were mixed with stirring using a disperser to obtain a coating composition 13 (pigment mass concentration: 14 mass%). The obtained coating composition 13 was applied onto an asphalt felt 430 (manufactured by Shizuoka Asphalt Industry Co., Ltd.) to a wet film thickness of 1000 μm. On its surface, 54.1 parts by mass of a filler (E1-5) was scattered in a visually uniform manner, and then the coating composition 13 was applied thereon to a wet film thickness of 1000 μm. After drying at 60°C for 20 minutes and then standing at room temperature for 1 day, a test piece 14 was obtained. It should be noted that the mass ratio of the main agent (S-1) to the curing agent (K-1) was 9:1.

[0343] Details of each component shown in Table 4 below used in the examples and comparative examples are as follows.

[0344] Coating film-forming resin (A)

[0345] (A-1) Aroset 5534-SB60 (acrylic polyol resin, manufactured by Nippon Shokubai Co., Ltd.): weight average molecular weight: 50000, acid value: 10 mgKOH / g, hydroxyl value: 38 mgKOH / g, solid content concentration: 60 mass%

[0346] Crosslinking agent (C)

[0347] (C-1) Duranate TSA-100 (HDI isocyanurate type polyisocyanate, manufactured by Asahi Kasei Corporation); NCO content: 20.6%, solid content concentration: 100 mass%

[0348] Solvent (D)

[0349] (D2-1) T-SOL 100 (aromatic hydrocarbon solvent, manufactured by Exxon Chemical Company)

[0350] Details of the aggregate (E1) and other aggregates (E2) shown in Table 4 below used in the examples and comparative examples are shown in Table 3.

[0351] In Table 3, the mixed particles are mixed particles of SiO2, Al2O3, Fe2O3, TiO2, CaO, and Cr2O3.

[0352] The near-infrared reflectance, spectral reflectance at wavelengths 905 nm and 1550 nm, particle size distribution, and average particle size of the aggregate measured by the sieving method are shown in Table 3. Sieves with pore diameters of 180 μm, 212 μm, 300 μm, 425 μm, 500 μm, and 1000 μm were used in the sieving method.

[0353] [Table 3]

[0354]

[0355] <Evaluation method>

[0356] 1) Coating film lightness

[0357] According to 3.2 of JIS K 5600-4-4 and JIS K 5600-4-5, use a color difference meter CM-500 (manufactured by Konica Minolta) to measure the lightness (L* value) of the coating film surface of the test pieces obtained in the examples and comparative examples.

[0358] 2) Near-infrared reflectance and spectral reflectance

[0359] For the test pieces obtained in the examples and comparative examples, use a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600) to measure the reflectance in the wavelength range of 800 to 2500 nm at intervals of 2 nm wavelengths according to the method of JIS K-5602. Take the arithmetic mean of the reflectances obtained at each wavelength as the near-infrared reflectance of the coating film. In addition, the near-infrared reflectances at 905 and 1550 nm are the values of the spectral reflectances at each wavelength.

[0360] 3) Surface roughness

[0361] According to JIS B 0601, use a laser microscope VK-X200 (manufactured by KEYENCE Corporation) to measure the arithmetic mean height (Sa: μm) and root mean square height (Sq: μm) of the coating film surface of the test pieces obtained in the examples and comparative examples.

[0362] 4) LiDAR visibility

[0363] Use LiDAR Mid-40 (manufactured by Livox, wavelength: 905 nm, incident angles: 0° and 80°) to observe the test pieces obtained in the examples and comparative examples from a location 3 m away. Visually observe the state of the test pieces obtained from the imaging images, and measure the reflectances at 10 randomly selected locations from the entire test piece. Take the arithmetic mean of them as the LiDAR reflectance of the test piece, and evaluate it according to the following criteria. A score of 3 or more is considered qualified.

[0364] 5: The LiDAR reflectance of the test piece is 100 or more

[0365] 4: The LiDAR reflectance of the test piece is 50 or more and less than 100

[0366] 3: The LiDAR reflectance of the test piece is 30 or more and less than 50

[0367] 2: The LiDAR reflectance of the test piece is 10 or more and less than 30

[0368] 1: The LiDAR reflectivity of the test piece is less than 10

[0369] 5) Skid resistance

[0370] Regarding the test pieces obtained in the examples and comparative examples, according to the "6-5 Method for Measuring the Skid Resistance of Paved Surfaces" in the "Handbook of Pavement Survey and Test Methods (2019 Edition)" edited by the Japan Road Association, the skid resistance value (BPN: British Pendulum Number) was measured to evaluate the skid resistance.

[0371] That is, the measurement was carried out as follows: Using a skid resistance value testing machine TR-300 (portable skid resistance tester, manufactured by Freesia Macross Co., Ltd.), tap water was sprinkled on the surface of the test piece fixed on the horizontal ground, and the rubber plate at the front end of the oscillator was dropped from a certain height to make the surface of the test piece contact with the rubber plate, and the attenuation (the resistance value at this time) caused by the friction between the surface of the test piece and the rubber plate was read with a scale. The test was carried out at 23 °C (t). In addition, the skid resistance value (BPN value) was set as the average value of 5 measurements with the variation of the measured value within 3 BPN. The larger this value is, the greater the skid resistance, which means better skid resistance. It should be noted that the skid resistance value is obtained by converting the actually measured skid resistance value (C t ) at the test temperature of 23 °C (t) into the skid resistance value (C 20 ) at 20 °C according to the following conversion formula.

[0372] C 20 =-0.0071×t 2 +0.9301×t - 15.79 + Ct

[0373] The evaluation criteria are as follows, with 3 or more being considered qualified.

[0374] 5: 80 BPN or more and 100 BPN or less

[0375] 4: 70 BPN or more and 80 BPN or less

[0376] 3: 50 BPN or more and 70 BPN or less

[0377] 2: 30 BPN or more and 50 BPN or less

[0378] 1: 0 BPN or more and 30 BPN or less

[0379] [Table 4]

[0380]

[0381] [Table 5]

[0382]

[0383] Examples 1 to 14 are examples of the present disclosure. The detection accuracy in LiDAR technology is high. In particular, even when the lightness (L* value) is low, the detection accuracy in LiDAR technology is still high.

[0384] Comparative Examples 1 and 2 are examples where pigments and aggregates capable of reflecting near-infrared light are not used. The skid resistance is poor, and the retroreflectivity is also poor, and the LiDAR visibility cannot be fully satisfied.

[0385] Comparative Example 3 is an example where aggregates are not used. The anti-slip property is poor, and at high incident angles, the retroreflectivity is poor, and the LiDAR visibility cannot be fully satisfied.

[0386] Comparative Examples 4 to 7 are examples where aggregates with a near-infrared reflectance of 5% or more are not used, and the retroreflectivity (especially the retroreflectivity at high incident angles) cannot be fully satisfied.

[0387] Industrial applicability

[0388] Even when the coating composition and the coating film are formed on a road surface, a marking can be achieved that can exhibit high retroreflectivity (especially the retroreflectivity at high incident angles) without being mistaken for a white line. According to such a marking, the detection accuracy of near-infrared rays in LiDAR technology can be improved. Preferably, even at low lightness, the detection accuracy of near-infrared rays in LiDAR technology can be improved. In particular, the detection accuracy of the incident angle during long-distance recognition is envisaged, and it is useful as a coating and a coating film for a detection object using near-infrared light sensing.

Claims

1. A coating composition for detecting an object by near-infrared light sensing, the coating composition for detecting an object by near-infrared light sensing comprising a film-forming resin (A), a coloring pigment (B), and an aggregate (E), wherein, The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance. The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

2. The coating composition for detecting an object by near-infrared light sensing according to claim 1, wherein, The average particle size of the aggregate (E1) is 50 μm or more.

3. The coating composition for detecting an object by 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 coating composition for detecting an object by near-infrared light sensing according to claim 1, wherein, The colored pigment contains at least one selected from a red pigment, a yellow pigment, and a blue pigment.

5. The coating composition for detecting an object by near-infrared light sensing according to claim 1, wherein, The red pigment and the yellow pigment each contain an organic pigment and / or an inorganic pigment.

6. The coating composition for detecting an object by near-infrared light sensing according to claim 1, wherein, The coloring pigment (B) contains at least one selected from the following: a white pigment having a spectral reflectance of 60% or more at a wavelength of 905 nm and / or 1550 nm, an organic red pigment having a spectral reflectance of 50% or more at the above wavelength, an inorganic red pigment having a spectral reflectance of 20% or more at the above wavelength, an organic yellow pigment having a spectral reflectance of 60% or more at the above wavelength, an inorganic yellow pigment having a spectral reflectance of 20% or more at the above wavelength, a blue pigment having a spectral reflectance of 40% or more at the above wavelength, an organic black pigment having a spectral reflectance of 30% or more at the above wavelength, and an inorganic black pigment having a spectral reflectance of 15% or more at the above wavelength.

7. The coating composition for detecting an object by near-infrared light sensing according to claim 1, wherein the lightness of the formed film is 80 or less.

8. A coating film for detecting an object by near-infrared light sensing, having a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm, The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

9. A coating film for detecting an object by near-infrared light sensing, formed from the coating composition according to any one of claims 1 to 7.

10. The coating film for detecting an object by near-infrared light sensing according to claim 9, having a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm, The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

11. The coating film for a detection object for sensing using near-infrared light according to any one of claims 9, having a spectral reflectance of 20% or more at a wavelength of 905 nm and / or 1550 nm, The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

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

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

14. A sensing method for measuring the distance between a vehicle and a detection object, in which near-infrared light of a specific wavelength is irradiated from a traveling vehicle, the near-infrared light is reflected on 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, wherein, The coated article is obtained by coating the coating composition according to any one of claims 1 to 7.

15. A method for manufacturing a coating film, comprising: Coating 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 using near-infrared light sensing, The first coating composition contains a film-forming resin (A), a coloring pigment (B), and an aggregate (E), The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance. The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

16. A method for manufacturing a coating film, comprising: Coating a second coating composition on a road surface to obtain a second coating film, Scattering the aggregate (E) on the second coating film, and Drying the second coating film to obtain a coating film for a detection object using near-infrared light sensing, The second coating composition contains a film-forming resin (A) and a coloring pigment (B), The coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance. The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

17. A method for manufacturing a coating film, comprising: A third coating composition is applied to a road surface to obtain a third coating film, the aggregate (E) is scattered on the third coating film, and a fourth coating composition is applied to the third coating film on which the aggregate (E) has been scattered to obtain a fourth coating film, the third coating film and the fourth coating film are dried to obtain a coating film for a detection object for sensing using near-infrared light, the third coating composition contains a film-forming resin (A) and a coloring pigment (B), the fourth coating composition contains a film-forming resin (A) and a coloring pigment (B), the coloring pigment (B) contains at least one selected from the following: 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 2500 nm is defined as the near-infrared reflectance, The aggregate (E) contains an aggregate (E1) having a near-infrared reflectance of 5% or more.

18. The manufacturing method according to any one of claims 15 to 17, wherein, The coating film for a detection object for sensing using near-infrared light has a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2500 nm, The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

19. The manufacturing method according to any one of claims 15 to 17, wherein, The spectral reflectance of the coating film for a detection object for sensing using near-infrared light at a wavelength of 905 nm and / or 1550 nm is 20% or more, The root mean square height (Sq) measured according to ISO 25178 is 10 μm or more and / or the arithmetic mean height (Sa) measured according to ISO 25178 is 10 μm or more.

Images