WO2022255310A1

WO2022255310A1 - Coating composition and coating film

Info

Publication number: WO2022255310A1
Application number: PCT/JP2022/021963
Authority: WO
Inventors: 奨吉田; 貴博張; ジャックドロネー，ジャン
Original assignee: 日本ペイントコーポレートソリューションズ株式会社; 国立大学法人東京大学
Priority date: 2021-05-31
Filing date: 2022-05-30
Publication date: 2022-12-08
Also published as: TW202307152A; JP2022183945A; JP7178059B1; CN117425708A

Abstract

The present disclosure addresses the problem of providing a coating composition and a coating film which can increase near-infrared detection accuracy in LiDAR technology. Furthermore, the present disclosure addresses the problem of providing a coating composition and a coating film which preferably can increase near-infrared detection accuracy in LiDAR technology while having low brightness. The coating composition according to the present disclosure is for a detection object to be sensed with near-infrared radiation, the coating composition including a coating film-forming resin (A) and a color pigment (B). The color pigment (B) includes at least one selected from the group consisting of a white color pigment having a near-infrared reflectance rate of 60% or more, a chromatic color pigment having a near-infrared reflectance rate of 50% or more, and a black color pigment having a near-infrared reflectance rate of 30% or more, where the near-infrared reflectance rate is the reflectance rate in the wavelength region from 800 to 2,500 nm.

Description

Coating composition and coating film

The present disclosure relates to coating compositions and coating films, and in particular to coating compositions and coating films for objects to be detected in sensing using near-infrared light.

One of the remote sensing technologies using light is to irradiate an object with near-infrared light, visible light and/or ultraviolet light and measure the light reflected and/or scattered by the object. , and LiDAR (Laser Imaging Detection and Ranging) that detects the distance and direction from the irradiation position to the object. Such LiDAR technology is, for example, a highly automated vehicle that detects obstacles and automatically applies the brakes, measures the speed and inter-vehicle distance of surrounding vehicles, and controls the speed and inter-vehicle distance of the own vehicle. It is an essential technology for driving systems. In order to operate the highly automated driving system normally, it is necessary to improve the detection accuracy of LiDAR.
Further, LiDAR often uses near-infrared rays as irradiation light.

The resin composition used in the LiDAR technology is a resin composition containing a transparent resin and a light absorber, and a cured body obtained by molding the resin composition to a thickness of 1 mm has a wavelength of 380 nm or more and 700 nm or less. A resin composition has been proposed that has an average light transmittance of 40% or less and a light transmittance of 70% or more at the wavelength of laser light used in LiDAR (Patent Document 1).

JP 2017-167484 A

Most of the development of LiDAR technology is centered on hardware such as sensors and light sources. The aforementioned Patent Document 1 also relates to an invention relating to a material used for a wavelength selection filter arranged in front of an element for receiving reflected light of a laser beam. On the other hand, the inventors of the present invention are not on the hard side, that is, the side that detects the signal (reflected light, scattered light), but on the side that emits the signal, that is, the detection target, which can be said to be the soft side of the hard side. Focusing on increasing the intensity of emitted signals (reflected light, scattered light). Then, in order to improve the detection accuracy, the subject of increasing the reflection and/or scattering intensity of the near-infrared rays in the detection object was conceived.

Furthermore, when the reflection intensity and / or scattering intensity of the near-infrared rays is high, the reflection intensity and / or scattering intensity tends to be high even in the visible light region, which is a wavelength region close to the near-infrared rays. also tends to be higher. On the other hand, objects to be detected by the LiDAR technology include dark-colored (also referred to as low-brightness) road structures such as pavements and sidewalks. Therefore, the paint used for detection targets in LiDAR technology is required to have low brightness for light in the visible light range and high intensity for reflecting and/or scattering light in the near-infrared range. be done.

An object of the present disclosure is to provide a coating composition and a coating film that can improve near-infrared detection accuracy in LiDAR technology. Furthermore, an object of the present disclosure is to provide a coating composition and a coating film that are preferably low in brightness and that can improve near-infrared detection accuracy in LiDAR technology.

The disclosure includes the following.
[1] A coating composition for a detection target object for sensing using near-infrared light, comprising a coating film-forming resin (A) and a coloring pigment (B),
The coloring pigment (B) is a white pigment having a near-infrared reflectance of 60% or more when the reflectance in the wavelength range of 800 to 2,500 nm is defined as a near-infrared reflectance, and a near-infrared reflectance of 50% or more. and at least one selected from the group consisting of a chromatic pigment and a black pigment having a near-infrared reflectance of 30% or more, a detection target object for sensing using near-infrared light paint composition.
[2] The near-infrared light according to [1], wherein the chromatic pigment contains at least one selected from the group consisting of red pigments, yellow pigments and blue pigments. A paint composition for sensing objects.
[3] The detection target of sensing using near-infrared light according to [1] or [2], wherein the red pigment and the yellow pigment each contain an organic pigment and / or an inorganic pigment. paint composition for objects.
[4] The coloring pigment (B) is a white pigment having a spectral reflectance of 70% or more at a wavelength of 905 nm and/or 1,550 nm,
an organic red pigment having a spectral reflectance of 50% or more at the wavelength;
an inorganic red pigment having a spectral reflectance of 20% or more at the wavelength;
an organic yellow pigment having a spectral reflectance of 60% or more at the wavelength;
an inorganic yellow pigment having a spectral reflectance of 20% or more at the wavelength;
a blue pigment having a spectral reflectance of 40% or more at the wavelength;
At least one selected from the group consisting of an organic black pigment having a spectral reflectance of 30% or more at the wavelength and an inorganic black pigment having a spectral reflectance of 15% or more at the wavelength, [1] to [3], the coating composition for a detection target object of sensing using near-infrared light.
[5] The object to be detected for sensing using near-infrared light according to any one of [1] to [4], wherein the coating film formed has a brightness of 80 or less. paint composition.
[6] A coating film for a detection target object for sensing using near-infrared light, characterized by having a near-infrared reflectance of 15% or more in a wavelength range of 800 to 2,500 nm.
[7] A coating film for an object to be detected for sensing using near-infrared light, formed from the coating composition according to any one of [1] to [5].
[8] The coating film for detecting an object for sensing using near-infrared light according to [7], characterized by having a near-infrared reflectance of 15% or more in a wavelength range of 800 to 2,500 nm.
[9] The near-infrared light according to any one of [6] to [8], characterized in that the spectral reflectance at a wavelength of 905 nm and / or 1,550 nm is 20% or more. Coating for objects to be detected in sensing.
[10] A detection target having a coating film formed using the coating composition for a detection target for sensing according to any one of [1] to [5].
[11] A running vehicle irradiates near-infrared light of a specific wavelength, reflects it on a detection target, detects the reflected light, and calculates the distance from the vehicle to the detection target based on the time it takes for the reflection. In the sensing method for measuring the distance between the vehicle and the object to be detected, the painted object is obtained by applying the paint composition according to any one of [1] to [5]. A sensing method characterized by:
[12] A running vehicle irradiates a near-infrared light of a specific wavelength, reflects it on a detection target, detects the reflected light, and uses the frequency difference between the irradiation light and the reflected light to detect the detection target from the vehicle. In the sensing method for measuring the distance between the vehicle and the object to be detected, the painted object is obtained by applying the paint composition according to any one of [1] to [5]. A sensing method, characterized in that

The coating composition and coating film of the present disclosure can increase the near-infrared detection accuracy in LiDAR technology, and preferably, while having low brightness, can increase the near-infrared detection accuracy in LiDAR technology. be.

The coating composition is for sensing objects using near-infrared light, and contains a coating film-forming resin (A) and a pigment (B). Specifically, the sensing can be a remote sensing technology, irradiating a detection target with near-infrared rays, detecting reflected light and / or scattered light from the irradiated position, It can be a technique for specifying the distance and direction to the irradiation position.

The wavelength of the near-infrared light used for sensing is preferably 800 nm or more, more preferably 900 nm or more, preferably 2,500 nm or less, more preferably 2,000 nm or less, and still more preferably 1,600 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 eliminate the influence of sunlight. The wavelengths currently used in sensing are mainly 905 nm and/or 1,550 nm.

Hereafter, the paint composition for sensing objects using near-infrared light may be simply referred to as "paint composition".

[Coating film-forming resin (A)]
The coating film-forming resin (A) is a resin capable of forming a coating film, and resins commonly used in the field of coatings can be used. Examples of the coating film-forming resin (A) include thermosetting resins such as acrylic resins, polyester resins, polyurethane resins, alkyd resins, polyether resins, fluororesins, epoxy resins, silicone resins, and urea resins; A photocurable resin etc. are mentioned. The coating film-forming resin (A) may form a coating film by itself, or may form a coating film by the action of a cross-linking agent (C) described later. can be As the coating film-forming resin (A), one type may be used, or two or more types may be used in combination.

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

Examples of the monomer having a (meth)acryloyl group include (meth)acrylic acid; (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms; (meth)acrylic (Meth)acrylic monomers having a hydroxy group such as hydroxymethyl acid, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and N-methylol (meth)acrylamide; Lactone adducts of (meth)acrylic monomers having a hydroxy group; (meth)acrylonitrile; and the like.

As the monomer having an ethylenically unsaturated group, in addition to the monomer having the (meth)acryloyl group, a monomer having a carboxy group such as crotonic acid, itaconic acid, and fumaric acid; Anhydrides of monomers; vinyl monomers such as styrene; and the like.

The polyester resin represents a polymer having a plurality of ester bonds in the main chain, a reaction product of a polyol and a polycarboxylic acid; an addition polymer of a cyclic ester; a reaction product of the polyol and a polycarboxylic acid, and a cyclic ester; can be obtained as a reaction product;

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

The number of hydroxy groups contained in the polyol is preferably 2 or more, may be 3 or more, preferably 6 or less, more preferably 4 or less, in one molecule.

As the polyol, one type may be used, or two or more types may be used in combination.

The polycarboxylic acid means a compound having two or more carboxy groups in one molecule. Examples of the polycarboxylic acid include aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid and pyromellitic acid; tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, cyclohexane-1,4 -Dicarboxylic acid, alicyclic polycarboxylic acids such as 5-norbornene-2,3-dicarboxylic acid and methyl-5-norbornene-2,3-dicarboxylic acid; Aliphatic polycarboxylic acids such as acid, sebacic acid, succinic acid, dodecenylsuccinic acid; hydroxy acids of lactose; aromatic polycarboxylic acids, alicyclic polycarboxylic acids, anhydrides of aliphatic polycarboxylic acids; is mentioned. As said polycarboxylic acid, 1 type may be used and 2 or more types may be used together.

Examples of the cyclic ester include ε-caprolactone.

The above-mentioned polyester resins also include modified products of the above-mentioned polyester resins. Modification of the resin can be carried out by reacting the terminal of the main chain constituting the resin with a modifying agent. Examples of the modifier include compounds having a reactive group such as an isocyanate group, a hydroxy group, and a carboxyl group, and a silicone skeleton. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, acrylic-modified polyester resins, and silicone-modified polyester resins.

Examples of the urethane resin include a reaction product of polyol and polyisocyanate; a reaction product of the reaction product and a chain extender used as necessary; and the like.

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

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

The polyisocyanate means a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylylene diisocyanate; tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthyl aromatic polyisocyanates such as diisocyanate and 3,3'-dimethyl-4,4'-biphenylene diisocyanate; As said polyisocyanate, 1 type may be used and 2 or more types may be used together.

The chain extender means 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, and tetraethylenepentamine; aromatic polyamines such as tolylenediamine, xylylenediamine, and diaminodiphenylmethane. ; alicyclic polyamines such as diaminocyclohexylmethane, piperazine, 2,5-dimethylpiperazine, and isophoronediamine; hydrazine compounds such as hydrazine, succinic dihydrazide, adipic dihydrazide, and phthalic dihydrazide; -aminoethyl)amino]ethanol, alkanolamines such as 3-aminopropanediol;

In one embodiment, ester-based urethane resins, ether-based urethane resins, and carbonate-based urethane resins can be used as urethane resins.

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

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

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

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

When the coating film-forming resin (A) has a cationic group, the amine value of the coating film-forming resin (A) is preferably 5 mgKOH/g or more, preferably 50 mgKOH/g or less, more preferably 30 mgKOH/g. g or less.

The coating film-forming resin (A) may have a hydroxy group. When the coating film-forming resin (A) has a hydroxyl group, the hydroxyl value of the coating film-forming resin (A) is 5 mgKOH/g or more, preferably 7 mgKOH/g or more, more preferably 10 mgKOH/g or more. Yes, 35 mgKOH/g or less, preferably 30 mgKOH/g or less, more preferably 25 mgKOH/g or less.

Both the acid value and hydroxyl value are based on solid content and can be measured in accordance with JIS K 0070:1999. The amine value is based on solid content and can be measured according to JIS K 7237.

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

The weight average molecular weight of the coating film-forming resin (A) may be, for example, 2,000 or more, 10,000 or more, 50,000 or more, or 10,000, 000 or less, 2,000,000 or less, or 500,000 or less.
In the case of the emulsion-type water-dispersible resin, the weight-average molecular weight of the coating film-forming resin (A) may be, for example, 50,000 or more, 100,000 or more, or 150,000 or more. you can Also, it may be 10,000,000 or less, 2,000,000 or less, or 500,000 or less.
In the case of a resin soluble in the aqueous medium or organic solvent, for example, it may be 2,000 or more, may be 10,000 or more, may be 50,000 or more, and may be 100,000 or less. Well, it can be 80,000 or less.
In addition, in this specification, a weight average molecular weight is the value which carried out polystyrene conversion of the measured value by a gel permeation chromatography.

The content of the coating film-forming resin (A) is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, and preferably 90% by mass in the solid content of the coating composition. % by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less.

In the present specification, the solid content of the coating composition means the portion excluding the solvent (D), which will be described later, from all the components of the coating composition.

In addition to the coating film-forming resin (A), a thermoplastic resin can also be used in the coating composition within a range that does not affect the physical properties of the coating film to be formed. Examples of the thermoplastic resin include chlorinated olefin resins such as chlorinated polyethylene and chlorinated polypropylene; homopolymers or copolymers containing vinyl chloride, vinyl acetate, vinylidene chloride, etc. as monomer components; cellulose resin; acetal Resin; alkyd resin; chlorinated rubber resin; modified polypropylene resin (acid anhydride-modified polypropylene resin, etc.); fluorine resin (e.g., vinylidene fluoride resin, vinyl fluoride resin, copolymer of fluorinated olefin and vinyl ether, fluorine copolymers of polyolefins and vinyl esters) and the like. One type of the thermoplastic resin may be used, or two or more types may be used in combination. By using a thermoplastic resin together, it becomes easy to adjust the physical properties of the formed coating film according to the purpose.

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

As used herein, near-infrared reflectance means the arithmetic mean value of spectral reflectance measured in accordance with JIS K 5602:2008 in the wavelength range of 800 to 2,500 nm. The spectral reflectance can be measured using a spectrophotometer.

As used herein, the near-infrared reflectance of a pigment can be measured by forming a coating film containing the pigment and measuring the reflectance of the coating film. Specifically, the pigments, resins, and solvents described in Measurement Example 1 of the near-infrared reflectance and spectral reflectance of the pigments described later are mixed with the pigment mass concentration (also referred to as PWC) shown in the following formula in a range of 3 to 50% by mass. After mixing to obtain a dispersion, using a disperser for 60 minutes at a rotation speed of 1,800 rpm to obtain a dispersion, black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) is used as a base, and an 8 mil doctor blade is used. was applied so that the thickness after drying was about 50 μm, and dried at 60° C. for 20 minutes to form a dry coating film. In accordance with JIS K 5602: 2008, using a spectrophotometer, the spectral reflectance of the white portion of the dry coating film is measured in the wavelength range of 800 to 2,500 nm, and the arithmetic average value is the pigment. is the near-infrared reflectance of Further, spectral reflectance at wavelengths of 905 nm and 1,550 nm, which will be described later, can also be measured according to the method for measuring spectral reflectance described above. As the spectrophotometer, for example, a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600, etc.) can be used for measurement.
Pigment mass concentration (PWC: mass%) = (pigment solid content) / (pigment solid content + resin solid content) x 100

In this specification, the solid content of the resin can be obtained by measuring the heating residue (the mass of the residue after heating at 105°C for 60 minutes) in accordance with JIS K 5601-1-2 (2008). can.

In addition, when measuring the near-infrared reflectance and spectral reflectance, the pigment mass concentration of each pigment was such that when a dry coating film was formed on the black and white opacity test paper, the white and black backgrounds could be seen through. The concentration should be higher than the concentration at which there is no state. In this specification, the pigment mass concentration of each pigment is 25% by mass for the organic red pigment, 30% by mass for the inorganic red pigment, 25% by mass for the organic yellow pigment, and 25% by mass for 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.

The pigment (B1) preferably contains a pigment selected from the group consisting of chromatic pigments and achromatic pigments. The chromatic pigments include any pigment with a color saturation exceeding 0, and examples thereof include red pigments, green pigments, blue pigments, yellow pigments, etc. Red pigments, It preferably contains one or more selected from the group consisting of blue pigments and yellow pigments, and more preferably contains one or more selected from the group consisting of red pigments, blue pigments and yellow pigments. .

Moreover, an organic pigment and/or an inorganic pigment can be used as the pigment (B1). The organic pigments tend to have high chroma and high near-infrared reflectance, while the inorganic pigments tend to have high weatherability.
The content of the organic pigment in the pigment (B1) may be 0% by mass or more, 0.5% by mass or more, or 3% by mass or more. Also, it may be 100% by mass or less, 70% by mass or less, 20% by mass or less, 10% by mass or less, or 8% by mass or less.
The content of the inorganic pigment in the pigment (B1) may be 0% by mass or more, 5% by mass or more, or 10% by mass or more. Also, it may be 100% by mass or less, 99% by mass or less, 50% by mass or less, 40% by mass or less, or 20% by mass or less.

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

An organic pigment and/or an inorganic pigment can be used as the red pigment. The content of the organic pigment may be 0% by mass, 1% by mass or more, 20% by mass or more, or 50% by mass or less in the red pigment. , the upper limit is 100% by mass.

The near-infrared reflectance of the organic red pigment is preferably 40% or higher, more preferably 45% or higher, even more preferably 50% or higher, and still more preferably 55% or higher. % or less is also acceptable.

The spectral reflectance of the organic red pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 40% or higher, more preferably 50% or higher, even more preferably 55% or higher, and still more preferably 60% or higher. , 90% or less, or even 85% or less.

The near-infrared reflectance of the inorganic red pigment is preferably 40% or more, more preferably 45% or more.

The spectral reflectance of the inorganic red pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 20% or more, more preferably 30% or more, for example, 90% or less, and is also allowed to be 85% or less. be.

Examples of red pigments as the pigment (B1) include, for example, organic red pigments such as Fastogen Super Magenta RH, Fastogen Red 7100Y, Fastogen Super Red 500RG, Fastogen Super Red ATY, Fastogen Super Blue Violet RVS, Rubicron Red 40 , Rubicron Red 500 RG (both manufactured by DIC), Cinilex DPP RED SR1C (manufactured by CINIC Chemicals), Todacolor 120 ED (manufactured by Toda Kogyo), BAYFERROX 130M (manufactured by Lanxess), etc., as inorganic red pigments. can be done.

The near-infrared reflectance of the blue pigment as the pigment (B1) is preferably 40% or higher, more preferably 45% or higher.

The spectral reflectance of the blue pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 30% or more, more preferably 35% or more, for example, 90% or less, and even 85% or less is acceptable. be done.

Examples of the blue pigment include Dipyroxide Color Blue 9453 (manufactured by Dainichiseika Kogyo Co., Ltd.), Fastogen Blue 9453, Fastogen Blue RS, Fastogen Blue 5380, Fastogen Super Blue 6070S (all manufactured by DIC), and Cyanine Blue 5240 KB. , Cyanine Blue 5050 (both manufactured by Dainichiseika Kogyo Co., Ltd.), HELIOGEN BLUE L7460 (manufactured by BASF), Dipyroxide Color Green 9310 (manufactured by Dainichiseika Kogyo Co., Ltd.), Fastogen Green 2 YK, Fastogen Green MY (both manufactured by DIC) ), Lionol Green 6YKP-N (manufactured by Toyocolor Co., Ltd.), and the like.

Near-infrared reflectance of the yellow pigment is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, still more preferably 55% or more, for example, 90% or less, further 85% It is also permissible to be

The spectral reflectance of the yellow pigment at a wavelength of 905 nm and / or 1,550 nm is preferably 15% or more, more preferably 20% or more, still more preferably 25% or more, still more preferably 30% or more. 95% or less, or even 90% or less is acceptable.

An organic pigment and/or an inorganic pigment can be used as the yellow pigment. The content of the organic pigment may be 0% by mass, 1% by mass or more, or 10% by mass or more in the yellow pigment. Moreover, it may be 50% by mass or less, and the upper limit is 100% by mass.

The near-infrared reflectance of the organic yellow pigment is preferably 40% or higher, more preferably 45% or higher, even more preferably 50% or higher, and still more preferably 55% or higher. % or less is also acceptable.

The spectral reflectance of the organic yellow pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 40% or higher, more preferably 45% or higher, even more preferably 50% or higher, and still more preferably 55% or higher. , 95% or less, or even 90% or less.

Near-infrared reflectance of the inorganic yellow pigment is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, still more preferably 55% or more, for example, 90% or less, further 85 % or less is also acceptable.

The spectral reflectance at a wavelength of 905 nm and / or 1,550 nm of the inorganic yellow pigment is preferably 20% or more, more preferably 25% or more, for example, 90% or less, even 85% or less Permissible.

Examples of the yellow pigment include, for example, Symuler Fast Yellow 4192 (manufactured by DIC), Hosta Perm Yellow H3G (manufactured by Clariant Japan), etc., as organic yellow pigments. Examples of inorganic yellow pigments include Sycopearl Yellow L-1110, Sycopearl Yellow L-1100 (both manufactured by BASF), TAROX synthetic iron oxide YM1100 (made by Titan Kogyo Co., Ltd.), and the like.

The chromatic pigment as the pigment (B1) preferably contains a red pigment, a blue pigment and a yellow pigment. For example, Symuler Fast Yellow 4192 (manufactured by DIC) as a yellow pigment, Fastogen Red 7100Y (manufactured by DIC) as a red pigment, and Lionol Blue FG7980 (manufactured by Toyocolor) as a blue pigment. Mixed things etc. can be mentioned.

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

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

The achromatic pigments include all pigments with a saturation of 0. Examples of the achromatic pigment include white pigments, gray pigments, and black pigments, including white pigments and black pigments.

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 more preferably 75% or more by mass. % or less, or even 90% or less.

Examples of the white pigment include titanium oxide TIPAQUE CR-97, TIPAQUE CR-95 (both manufactured by Ishihara Sangyo Co., Ltd.), and Taipure R-902 (manufactured by DuPont).

The spectral reflectance of the white pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 60% or more, more preferably 65% or more, still more preferably 70% or more, and still more preferably 75% by mass or more. , 99% or less, or even 90% or less.

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. Also, it may be 100% by mass or less, may be 99% by mass or less, may be 90% by mass or less, may be, for example, may be 60% by mass or less, may be 55% by mass or less, may be 50% by mass may be:

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, still more preferably 15% or more, for example 90%. Below, and further below 85% is also allowed.

The spectral reflectance of the black pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 5% or more, more preferably 8% or more, still more preferably 10% or more, and still more preferably 15% or more. 90% or less, or even 85% or less is acceptable.

An organic pigment and/or an inorganic pigment can be used as the black pigment. The content of the organic pigment in the black pigment may be 0% by mass, 1% by mass or more, 20% by mass or more, or 50% by mass or less. , the upper limit is 100% by mass.

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 more preferably 40% or more. % or less is also acceptable.

The spectral reflectance of the organic black pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 40% or more, more preferably 50% or more, still more preferably 55% or more, and still more preferably 60% or more. , 90% or less, or even 85% or less.

The near-infrared reflectance of the inorganic black pigment is preferably 30% or higher, more preferably 40% or higher.

The spectral reflectance of the inorganic black pigment at a wavelength of 905 nm and/or 1,550 nm is preferably 5% or more, more preferably 10% or more, for example, 85% or less, and is also allowed to be 80% or less. be.

Examples of the black pigment include inorganic black pigments such as Dipyroxide Color Black 9590, Dipyroxide Color Brown 9290, Dipyroxide Color Brown 9211 (all manufactured by Dainichiseika Kogyo Co., Ltd.), Black 411 (The Shepherd Color Company), Black 6350 (Asahi Kasei Kogyo), Chromofine Black A-1103 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as an organic black pigment, Fastogen Super Black MX (manufactured by DIC), Paryogen Black S0084, Pariotol Black L0080 (both manufactured by BASF), Hoster Palm Brown HFR-01 (manufactured by Clariant Japan) and the like can be mentioned.

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

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

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

As the pigment (B1), one type may be used, or two or more types may be used in combination.

In one embodiment, the pigment (B1) includes a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a near-infrared reflectance of 5% or more. At least one selected from the group consisting of black pigments. By including these pigments in the pigment (B1), it is possible to increase the detection accuracy of the near-infrared rays in the LiDAR technology of the resulting coating film. It is possible to improve the detection accuracy of

The pigment (B1) includes a white pigment having a near infrared reflectance of 60% or more, a blue pigment having a near infrared reflectance of 50% or more, a red pigment having a near infrared reflectance of 50% or more, a near It preferably contains at least one selected from the group consisting of a yellow pigment having an infrared reflectance of 50% or more and a black pigment having a near infrared reflectance of 30% or more; wavelength 905 nm and / or 1,550 nm A white pigment with a spectral reflectance of 70% or more at a wavelength of 905 nm and / or a blue pigment with a spectral reflectance of 40% or more at a wavelength of 1,550 nm, a spectral reflectance of 50 at a wavelength of 905 nm and / or 1,550 nm % or more, an inorganic red pigment having a spectral reflectance of 20% or more at a wavelength of 905 nm and/or 1,550 nm, and a spectral reflectance of 60% or more at a wavelength of 905 nm and/or 1,550 nm An organic yellow pigment, an inorganic yellow pigment having a spectral reflectance of 20% or more at a wavelength of 905 nm and/or 1,550 nm, and an organic black pigment having a spectral reflectance of 50% or more at a wavelength of 905 nm and/or 1,550 nm , inorganic black pigments having a spectral reflectance of 15% or more at a wavelength of 905 nm and/or 1,550 nm.

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

The coloring pigment (B) contains a coloring pigment (b) other than the pigment (B1) within a range that does not affect the near-infrared reflectance and spectral reflectance of the coating film obtained from the coating composition. You can As the coloring pigment (b), any compound other than the pigment (B1) can be used among the compounds classified as pigments in the Color Index. Examples of the coloring pigment (b) include organic black pigments such as carbon black. The content rate (pigment mass concentration) of the coloring pigment (b) may be 1% by mass or less, may be 0.5% by mass or less, and may be 0.1% by mass or less in the coloring pigment (B). can be

The content of the pigment (B) (pigment mass concentration) is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 15% by mass or more, based on the total of the coating film-forming resin (A) and the pigment (B). is 20% by mass or more, preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less.

The lightness (L* value) of the coating film obtained from the coating composition is preferably 80 or less, and may be 5 or more, for example. Also, for example, it may be 70 or less, or 15 or more. By using the coating composition of the present disclosure, visibility in LiDAR technology can be maintained even when the lightness (L* value) of the coating film is low. The lightness (L* value) of the coating film may change depending on the thickness (film thickness) of the coating film.

In this specification, the brightness of the coating film can be measured by the same method as the brightness 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 described later are mixed so that the pigment mass concentration is 3 to 50% by mass, and the rotation speed is After dispersing using a disperser for 60 minutes at 1,800 rpm to form a dispersion, black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) is used as a base, and the thickness after drying is about 100 μm. It is applied and dried at 60° C. for 20 minutes to form a dry film. For the resulting coating film, the brightness of the white part of the dry coating film base obtained in accordance with JIS K 5600-4-4 3.2 and JIS K 5600-4-5 was measured. can be The brightness can be measured, for example, using a color difference meter CM-600d (manufactured by Konica Minolta).

Assuming that the desired lightness of the coating film is L* ₀ , the relationship between the range of L* ₀ and the pigment mass concentration of each pigment is expressed by the following equation. That is, the pigment mass concentration of each pigment may be in a range that satisfies the following formula. In addition, L* ₀ can take values within the range described above as the lightness of the coating film.
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 Expression (1)
Here, (W) is the pigment mass concentration (% by mass) of the white pigment, (IR) is the pigment mass concentration (% by mass) of the inorganic red pigment, and (OR) is the pigment mass concentration (% by mass) of the organic red pigment. %), (IY) is the pigment mass concentration (mass%) of the inorganic yellow pigment, (OY) is the pigment mass concentration (mass%) of the organic yellow pigment, (OB) is the pigment mass concentration of the blue pigment (mass %), (IBL) is the pigment mass concentration (% by mass) of the inorganic black pigment, and (OBL) is the pigment mass concentration (% by mass) of the organic black pigment.

Assuming that the near-infrared reflectance of the target coating film is X ₀ (%), the relationship between the X ₀ (%) and the pigment mass concentration of each pigment is expressed by the following equation. That is, the pigment mass concentration of each pigment may be in a range that satisfies the following formula. In addition, X ₀ (%) can take values within the range described above as the near-infrared reflectance of the coating film.
X ₀ = 0.5 (W) - 1.4 (IR) + 0.1 (OR) - 0.6 (IY) - 1.8 (OY) - 3.1 (OB) - 0.2 (IBL) -13.2 (OBL) + 61.0 Expression (2)

The relationship between the pigment mass concentration of each pigment and the spectral reflectance of the target coating film at a wavelength of ₉₀₅ nm is represented by the following equation. That is, the pigment mass concentration of each pigment may be in a range that satisfies the following formula. Moreover, Y ₀ (%) can take values within the range described above as the spectral reflectance of the coating film at a wavelength of 905 nm.
Y ₀ = 0.6 (W) - 2.9 (IR) + 3.5 (OR) - 1.2 (IY) - 0.9 (OY) - 3.0 (OB) - 0.8 (IBL) -1.2 (OBL) + 68.0 Expression (3)

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

The brightness of the coating film may be 80 or less. The combination of each pigment mass concentration at that time is variously calculated by the formula (1). Among the combinations, the near-infrared reflectance, the spectral reflectance at a wavelength of 905 nm, and the spectral reflectance at a wavelength of 1,550 nm are set to desired values or more (for example, 15% or more) according to formulas (2) to (4). Each pigment concentration combination can be calculated.

[Crosslinking agent (C)]
The coating composition may contain a cross-linking agent (C) in addition to the coating film-forming resin (A) and the pigment (B). The cross-linking agent (C) is a compound capable of forming a cross-linked structure in the coating film-forming resin (A) by forming a chemical bond and/or a physical bond. A compound having two or more groups having an active hydrogen atom in one molecule; or a compound having two or more groups capable of reacting with the group having an active hydrogen atom in one molecule; and the like. When the coating 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 reacts with the cross-linking agent (C) to form a coating film-forming resin (A). A crosslinked structure may be formed therein.

Examples of the cross-linking agent (C) include polyisocyanate compounds; blocked polyisocyanate compounds; amino resins; phenol resins; These may be used alone or in combination of two or more.

The polyisocyanate compound means a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate and mixtures thereof, naphthylene- Aromatic polyisocyanates such as 1,5-diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate and xylylene diisocyanate; polyisocyanate; aliphatic polyisocyanate such as hexamethylene diisocyanate;

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

The blocking agent may be any compound having an active hydrogen-containing compound. Examples include phenolic compounds such as phenol, cresol and xylenol; lactam compounds such as ε-caprolactam, δ-valerolactam and γ-butyrolactam; methanol and ethanol. , n-, i- or t-butyl alcohol and other aliphatic alcohol compounds; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether and other glycol ether compounds; benzyl alcohol and other aromatic compounds Alcohol compounds; oxime compounds such as formamide oxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monoxime, benzophenone oxime, and cyclohexane oxime; active methylene compounds such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, and acetylacetone; be able to. Free isocyanate groups of the polyisocyanate compound can be blocked by mixing the polyisocyanate compound and the blocking agent.

The amino resin means a resin obtained by addition polymerization of an aldehyde to a compound having an amino group. The amino resin is preferable because it has excellent cross-linking reactivity with the coating film-forming resin (A), and is particularly excellent in cross-linking reactivity with the coating film-forming resin (A) even in the absence of a catalyst.

Examples of the amino resin include melamine resin, urea resin, etc., and melamine resin is preferable.

The melamine resin means a thermosetting resin synthesized from melamine and aldehyde. The melamine resin has a triazine nucleus and three reactive functional groups (-NX ₁ X ₂ ) per triazine nucleus. As the melamine resin, a completely alkylated type containing only -N(CH ₂ OR) ₂ [R represents an alkyl group having 1 to 8 carbon atoms, the same shall apply hereinafter] as a reactive functional group; Methylol group type including —N(CH ₂ OR) (CH ₂ OH); imino group type including —N(CH ₂ OR) (H) as a reactive functional group; —N(CH ₂ OR)(CH ₂ OH) and —N(CH ₂ OR)(H), or —N(CH ₂ OH)(H), or methylol/imino group types. As said melamine resin, 1 type may be used and 2 or more types may be used together. The melamine resin and the polyisocyanate compound may be used in combination as the cross-linking agent (C). Moreover, you may use metal catalysts, such as a tin compound and a titanium compound, as needed.

Examples of the phenol compound include glycidyl ether type resins such as a condensation reaction product of bisphenol A and epichlorohydrin, a condensation reaction product of bisphenol F and epichlorohydrin; group epoxy resins, bromine-containing epoxy resins, phenol novolak type epoxy resins, cresol novolak type epoxy resins;

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

In one embodiment, the cross-linking agent (C) is preferably one or more selected from the group consisting of polyisocyanate compounds, blocked polyisocyanate compounds and amino resins.

The content of the cross-linking agent (C) may be, for example, 3 parts by mass or more, or 10 parts by mass in a total of 100 parts by mass of the coating film-forming resin (A) and the cross-linking agent (C). or more, may be 15 parts by mass or more, or may be 20 parts by mass or more. Further, for example, it may be 50 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less.

The total content of the coating film-forming resin (A) and the crosslinking agent (C) is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass in the solid content of the coating composition. % by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 80% by mass or less.

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

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

Examples of the hydrophilic solvent include glycol-based solvents such as ethylene glycol, propylene glycol, butanediol, pentanediol, diethylene glycol, dipropylene glycol, and triethylene glycol; ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether, diethylene glycol di Glycol ether solvents such as butyl 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 a hydrophilic solvent, there is an advantage that the wettability of the obtained coating composition with the substrate is improved.

Examples of the organic solvent (D2) include ether solvents such as dioxane and tetrahydrofuran; ester solvents such as 3-methoxybutyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, and the like. and aromatic hydrocarbon solvents such as toluene, T-SOL 100, and T-SOL 150 (both manufactured by Exxon Chemicals); pentane, iso-pentane, hexane, iso-hexane, cyclohexane, etc. Hydrocarbon-based solvent; Mineral oils such as solvent naphtha and mineral spirits can be mentioned. These may be used alone or in combination of two or more.

The coating composition may be an aqueous coating composition containing mainly an aqueous medium (D1) as the solvent (D), or a solvent-based coating composition containing mainly an organic solvent (D2) as the solvent (D). It's okay. When the coating composition is a water-based 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, preferably It is 100% by mass or less. When the coating composition is a solvent-based coating composition, the content of the organic solvent (D2) is preferably 50% by mass or more, more preferably 70% by mass or more, in the solvent (D). is 100% by mass or less.

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

The coating composition may be a water-based coating, an organic solvent-based coating, or a solvent-free coating, such as a powder coating.

The coating composition may further contain other additives. Examples of the other additives include surface conditioners; extender pigments; colorants such as dyes; waxes; agents, etc.); antioxidants (phenol-based, sulfoid-based, hindered amine-based antioxidants, etc.); plasticizers; coupling agents (silane-based, titanium-based, zirconium-based coupling agents, etc.); pigment dispersants; pigment wetting agents; leveling agents; anti-separation agents; These additives may be used alone or in combination of two or more.

Examples of the bright pigment include mica, aluminum foil, tin foil, gold foil, silver foil, titanium gold foil, stainless steel foil, metal foil such as nickel and copper, and the like.

Examples of the filler _include _SiO2 , _TiO2 , _Al2O3 , _Cr2O3 _, _ZrO2 , _Al2O3.SiO2 , _3Al2O3.2SiO2 _, zirconia silicate, ceramic _beads _, and the like _. fibrous or granular fine glass; glass beads; resin beads and the like. Resins constituting the resin beads include acrylic resins, urethane resins, polyester resins, polyamide resins, polystyrene resins, polyethylene resins, melamine resins, urea resins, fluorine resins, polyacrylonitrile resins, and the like. Further, the term "particulate" means particulate, spherical, or hollow spherical. The resin beads are preferably spherical.

The average particle size of the filler may be, for example, 100 nm or more, or 500 nm or more. Moreover, it may be 500 μm or less, or may be 200 μm or less. In the present specification, the average particle size means the volume average particle size (D50), which can be measured using a laser Doppler particle size analyzer (for example, Microtrac UPA150 manufactured by Nikkiso Co., Ltd.). .

The coating composition contains the coating film-forming resin (A), the pigment (B), and the optionally used crosslinking agent (C) and other additives in the optionally used solvent (D). It can be prepared by dissolving or dispersing. In addition, the order of mixing the various materials used is not particularly limited. A coating composition may be produced by mixing with other components to be used as appropriate. The coating composition of the present specification is prepared by, for example, selecting and using a mixer such as a sand grind mill, a ball mill, a blender, a paint shaker or a disper, a disperser, a kneader, etc., and mixing each component. can do.

The coating film obtained from the coating composition may have a lightness (L* value) of 80 or less, for example, 70 or less. Also, for example, it may be 5 or more, or 15 or more.

The brightness of the coating film can be measured, for example, using a colorimeter in accordance with JIS K 5600-4-4 3.2 and JIS K 5600-4-5. As a color difference meter, for example, CM-600d (manufactured by Konica Minolta) can be used for measurement.

In this specification, the coating film used in measuring the brightness, near-infrared reflectance and spectral reflectance can be formed, for example, by the following method.
The coating composition is applied to black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) as a base so that the thickness after drying is 30 μm or more and 2,000 μm or less, and heated at 20 ° C. or more and 200 ° C. or less. temperature for 10 minutes or more and 24 hours or less to obtain a dry coating film. The part where the lightness (L* value) is measured may be the lightness of the part where the base of the obtained dry coating film is white.

Since the near-infrared wavelength range is close to the visible light range, paint compositions with high near-infrared reflectance tend to have high visible light reflectance and high brightness. In general, 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 having the above configuration can easily increase the near-infrared reflectance while reducing the brightness.

The brightness of the coating composition measured by the above method may be, for example, 90 or less, or 80 or less. Also, it may be 3 or more, or 5 or more.

The coating film obtained from the coating composition preferably has an arithmetic mean height (Sa) of 1 µm or more, or a root mean square height (Sq) of 1 µm or more. More preferably, Sa is 3 µm or more, or Sq is 5 µm or more, and more preferably Sa is 5 µm or more, or Sq is 10 µm or more. When it is within such a range, there is an advantage that LiDAR visibility is improved.

The surface roughness of the coating film can be measured according to JIS B 0601. Based on the surface roughness measurement, the arithmetic mean height and the root mean square height are calculated, respectively, and used 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 (for example, a laser microscope VK-X200 manufactured by Keyence Corporation).

The arithmetic mean height (also referred to as "Sa") is a parameter that indicates the roughness of the surface of the coating film. represents the average. 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 is more uneven. Further, the root mean square height (also referred to as “Sq”) is a parameter corresponding to the standard deviation of the distance from the average plane of the surface of the coating film.

The coating film can be formed, for example, by the following method.
The coating composition is applied to a tin plate (manufactured by TP Giken Co., Ltd.) so that the thickness after drying is 30 μm or more and 2,000 μm or less, and the heating temperature is 20° C. or more and 200° C. or less for 10 minutes or more and 24 hours. Heating is then carried out to obtain a dry coating film.

A coating film formed from the coating composition is also included in the technical scope of the present disclosure.

The near-infrared reflectance of the coating film is preferably 15% or more, more preferably 30% or more, still more preferably 35% or more, for example, 99% or less, even 90% or less is acceptable. .

The spectral reflectance of the coating film at a wavelength of 905 nm and/or 1,550 nm is preferably 20% or more, more preferably 30% or more, still more preferably 35% or more, for example, 99% or less, further 90% It is also permissible to be

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

The coating film can be formed, for example, by the following method.
The coating composition is applied to black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) as a base so that the thickness after drying is 30 μm or more and 2,000 μm or less, and the heating temperature is 20 ° C. or more and 200 ° C. or less. and heat for 10 minutes to 24 hours to obtain a dry coating film.

Examples of objects to be coated with the coating film include metal plates, members made of metal plates, plastic members, inorganic material members, wooden members, pavements such as road surfaces, and the like.

Examples of the metal sheet include galvanized steel sheet, zinc-aluminum alloy-coated steel sheet, aluminum alloy-coated steel sheet, hot-dip zinc-aluminum-magnesium alloy-coated steel sheet, stainless steel sheet, and cold-rolled steel sheet, which are produced by a fusion method or an electrolytic method. and other metal plates. In addition to these steel sheets or plated steel sheets, metal sheets such as aluminum sheets (including aluminum alloy sheets) can also be applied. The metal plate is preferably surface-treated. Specifically, the metal plate is preferably subjected to chemical conversion treatment after pretreatment such as alkaline degreasing treatment, hot water washing treatment, and water washing treatment. The chemical conversion treatment may be carried out by a known method, examples of which include chromate treatment, non-chromate treatment such as zinc phosphate treatment, and the like. The surface treatment can be appropriately selected according to the steel sheet to be used, but a treatment that does not contain heavy metals is preferable.

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

Examples of the inorganic members include ceramic building materials and glass substrates described in JIS A 5422, JIS A 5430, etc. Examples include silica calcium plates, pulp cement plates, slag gypsum plates, and magnesium carbonate plates. , asbestos perlite board, wood chip cement board, hard wood cement board, concrete board, lightweight aerated concrete board and the like.

Examples of the wooden members include sawn lumber, laminated lumber, plywood, particle board, fiber board, improved lumber, chemical-treated lumber, and floorboards.

Examples of pavements such as road surfaces include asphalt pavement, concrete pavement, and brick pavement.

Specific examples of the objects to be coated include structures and articles that may become obstacles during automatic driving of automobiles. For example, various products sold, roads, road structures (e.g., pavements, road markings, sidewalks, crosswalks, drainage facilities, grade crossing structures, bridges, earthworks, tunnels, shelters, traffic safety facilities (e.g., three-dimensional Crossing facilities, guardrails, guard poles, protective fences, lighting facilities, visual guideposts, road reflectors, etc.), traffic islands, stops, parking zones, parking lots, etc.), various building structures and their internal facilities, railway structures, Examples include various protective facilities, various vehicles and their accessories, clothing worn by pedestrians, utility poles, inner walls of various building structures, and the like.

The coating film is formed by coating the coating composition on an object to be coated to form a coating film, and drying and/or curing the coating film at normal temperature or by heating as necessary. can be done.

The coating can be carried out, for example, by a spray coating method, a bar coater coating method, an air knife coating method, a gravure coating method, a brush coating method, an air gun coating method, an air electrostatic gun coating method, a dip coating method, or the like. can.

The thickness of the coating film can be, for example, 10 to 100 μm.

When the coating film is dried and/or cured by heating, the heating temperature is, for example, preferably 70 to 180°C, more preferably 80 to 140°C. The heating time is, for example, preferably 10 to 60 minutes, more preferably 15 to 45 minutes. As a heating means, hot air heating, infrared heating, induction heating, or the like can be employed.

Furthermore, a sensing method using near-infrared light using the coating film is also included in the technical scope of the present disclosure.
For example, a moving vehicle irradiates near-infrared light with a specific wavelength, and the reflected light is reflected on the object to be detected. In the sensing method for measuring the distance between the vehicle and the painted object (time-of-flight measurement method: ToF (Time-of-Flight)), the painted object is obtained by painting the paint composition can be In addition, near-infrared rays of a specific wavelength are emitted from a running vehicle, reflected by the object to be detected, and the reflected light is detected. In the sensing method for measuring the distance between the vehicle and the painted object (frequency modulated continuous wave method: FMCW (Frequency Modulated Continuous Wave)), the paint composition is applied to the painted object to calculate the distance to can be obtained.

The coating composition and the coating film can increase the near-infrared detection accuracy in LiDAR technology, and preferably, while having low brightness, can increase the near-infrared detection accuracy in LiDAR technology. It is useful as a coating material and a coating film for sensing objects using near-infrared light.

The present disclosure will be described more specifically with the following examples, but the present disclosure is not limited to these.

<Measurement example 1 of near-infrared reflectance and spectral reflectance of pigment>
Near-infrared reflectance of inorganic red pigment, measurement example of spectral reflectance at wavelength 905 nm and / or 1,550 nm As a coating film forming resin (A-1) Alloset 5534-SB60 21 parts by weight, as a solvent (D2-1) After mixing 6 parts by mass of T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) and 22 parts by mass of Todacolor 120ED (B21-1) as an inorganic red pigment, an SG mill (medium: glass beads) was used to adjust the dispersion particle size of the pigment. It dispersed until it became 10 micrometers or less. Next, 51 parts by mass of (A-1) was added and mixed with stirring using a disper to obtain a main component.

62 parts by mass of Duranate TSA-100 (C-1) as a cross-linking agent and 38 parts by mass of T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent (D2-1) were mixed while stirring with a disper to obtain a curing agent. rice field.

The main agent and curing agent obtained above were mixed at a mass ratio of 9:1 to obtain a paint composition (pigment mass concentration: 30 mass%). The obtained coating composition was coated on black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) using an 8 mil doctor blade so that the dry film thickness was 50 μm, dried at 60 ° C. for 20 minutes, and then dried at room temperature. and allowed to stand for one day to obtain a coating film.

For the resulting coating film, the white base portion is measured using a spectrophotometer (SHIMADZU-UV3600, manufactured by Shimadzu Corporation) in accordance with JIS K-5602. was measured every 2 nm wavelength. The arithmetic average value of the reflectance at each wavelength obtained was taken as the near-infrared reflectance of the inorganic red pigment. Also, the near-infrared reflectance at 905 and 1,550 nm is the value of the spectral reflectance at each wavelength.

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

<Production Example 1>
Production Example of White Pigment Paste 22 parts by mass of (A-1) Alloset 5534-SB60 as a coating film-forming resin, 7 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent, and a white pigment After mixing 34 parts by mass of (B1-1) TIPAQUE CR-97 as (B1-1), an SG mill (medium: glass beads) was used to disperse the pigment until the dispersed particle size was 10 μm or less. Next, 37 parts by mass of (A-1) was added and mixed with stirring using a disper to obtain a white pigment paste (W-1).

<Production Examples 2 to 9>
A pigment paste of each pigment was obtained in the same manner as in Production Example 1 except that the types and amounts of the coating film-forming resin, solvent and pigment used were changed as shown in Table 2.

<Manufacturing example of clear for adjusting PWC>
83 parts by mass of (A-1) Alloset 5534-SB60 as a coating film-forming resin and 17 parts by mass of (D2-1) T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) as a solvent were mixed while stirring using a disper. , to obtain a PWC adjusting clear.

<Example 1>
126.1 parts by mass of the white pigment paste (W-1) and 23.8 parts by mass of the clear for adjusting PWC were mixed while stirring with a disper to obtain a main component (S-1).

A curing agent (K-1) was obtained by mixing 38 parts by mass of T-SOL 100 (manufactured by Exxon Chemical Co., Ltd.) with 62 parts by mass of Duranate TSA-100 (C-1) as a cross-linking agent while stirring with a disper.

<Production example 1 of coating film (test piece)>
149.9 parts by mass of the main agent (S-1) and 16.7 parts by mass of the curing agent (K-1) obtained above were mixed while stirring with a disper to obtain a coating composition 1 (pigment mass concentration: 42% by mass). The obtained coating composition 1 is applied to black and white hiding rate test paper (manufactured by Nippon Test Panel Co., Ltd.) so that the dry film thickness is 100 μm, dried at 60 ° C. for 20 minutes, and left at room temperature for 1 day. and a test piece 1 was obtained. The main agent (S-1) and the curing agent (K-1) were adjusted to a mass ratio of 9:1.

In the same manner as in Production Example 1 of the coating film (test piece) except that the types and amounts of the pigment paste, PWC adjusting clear, cross-linking agent and solvent used were changed as shown in Table 3, Each coating film (test piece) was obtained.
When the coating composition contained other materials, the other materials were mixed together with various pigment pastes and PWC-adjusting clears to prepare the main agent.

Details of each component shown in the following table used in Examples and Comparative Examples are as follows.
Coating film-forming resin (A)
(A-1) Aroset 5534-SB60 (acrylic polyol resin, manufactured by Nippon Shokubai Co., Ltd.): weight average molecular weight: 50,000, acid value: 10 mgKOH/g, hydroxyl value: 38 mgKOH/g, solid content concentration: 60% by mass
Crosslinking agent (C) (C-1) Duranate TSA-100 (HDI isocyanurate type polyisocyanate, manufactured by Asahi Kasei Corporation); NCO content: 20.6%, solid content concentration: 100% by mass
Solvent (D)
(D2-1) T-SOL 100 (aromatic hydrocarbon solvent, manufactured by Exxon Chemical Co.)
Other materials:
Filler: Gasil HP395 (amorphous silica, manufactured by PQ Corporation); Average particle size: 14.5 µm

A test piece was obtained by adjusting the main agent and curing agent in the same manner as in Example 1, except that the type and amount of each component were changed as shown in the table.

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

2) Near-infrared reflectance and spectral reflectance For the test pieces obtained in Examples and Comparative Examples, a spectrophotometer (manufactured by Shimadzu Corporation, SHIMADZU-UV3600) was used to measure 800 in accordance with JIS K-5602. The reflectance in the wavelength range of ~2,500 nm was measured at every 2 nm wavelength. The arithmetic average value of the reflectance at each wavelength obtained was taken as the near-infrared reflectance of the coating film. Also, the near-infrared reflectance at 905 and 1,550 nm is the value of the spectral reflectance at each wavelength.

3) Surface roughness The arithmetic mean height (Sa: μm) and the root mean square height (Sq: μm) of the coating surface of the test pieces obtained in Examples and Comparative Examples were measured according to JIS B 0601, It was measured using a laser microscope VK-X200 (manufactured by Keyence Corporation).

4) LiDAR visibility
The test pieces obtained in Examples and Comparative Examples were observed from a point 3 m away using LiDAR Mid-40 (manufactured by Livox, wavelength: 905 nm). The state of the test piece obtained from the imaging image was visually observed, and the reflectance was measured at 10 arbitrarily selected points from the entire test piece. The arithmetic average value was taken as the LiDAR reflectance of the test piece, and evaluated according to the following criteria. A score of 3 or more was considered as a pass.
5: The LiDAR reflectance of the test piece is 100 or more 4: The LiDAR reflectance of the test piece is 50 or more and less than 100 3: The LiDAR reflectance of the test piece is 30 or more and less than 50 2: The LiDAR reflectance of the test piece is 10 or more and less than 30 1: LiDAR reflectance of test piece is less than 10

Examples 1 to 11 are examples of the present disclosure, and the detection accuracy in the LiDAR technology was high, and the detection accuracy in the LiDAR technology was particularly high even when the lightness (L* value) was low.

In Comparative Examples 1 and 2, as pigments, a white pigment having a near-infrared reflectance of 60% or more, a chromatic pigment having a near-infrared reflectance of 50% or more, and a near-infrared reflectance of 30% or more. This is an example that does not contain any black pigment, and although it was possible to lower the brightness, the detection accuracy in the LiDAR technology was not sufficiently satisfactory.

The coating composition and coating film of the present disclosure can increase the near-infrared detection accuracy in LiDAR technology, and preferably, while having low brightness, can increase the near-infrared detection accuracy in LiDAR technology. and useful as paints and coatings for objects to be detected by LiDAR technology.

Claims

A coating composition for a detection target object for sensing using near-infrared light, comprising a coating film-forming resin (A) and a coloring pigment (B),
The coloring pigment (B) is a white pigment having a near-infrared reflectance of 60% or more when the reflectance in the wavelength range of 800 to 2,500 nm is defined as a near-infrared reflectance, and a near-infrared reflectance of 50% or more. and at least one selected from the group consisting of a chromatic pigment and a black pigment having a near-infrared reflectance of 30% or more, a detection target object for sensing using near-infrared light paint composition.
Detection of sensing using near-infrared light according to claim 1, wherein the chromatic pigment contains at least one selected from the group consisting of red pigments, yellow pigments and blue pigments. A coating composition for an object.
3. The coating composition for a detection object for sensing using near-infrared light according to claim 1 or 2, wherein the red pigment and the yellow pigment each contain an organic pigment and/or an inorganic pigment. .
The coloring pigment (B) is a white pigment having a spectral reflectance of 70% or more at a wavelength of 905 nm and/or 1,550 nm,
an organic red pigment having a spectral reflectance of 50% or more at the wavelength;
an inorganic red pigment having a spectral reflectance of 20% or more at the wavelength;
an organic yellow pigment having a spectral reflectance of 60% or more at the wavelength;
an inorganic yellow pigment having a spectral reflectance of 20% or more at the wavelength;
a blue pigment having a spectral reflectance of 40% or more at the wavelength;
At least one selected from the group consisting of an organic black pigment having a spectral reflectance of 30% or more at the wavelength and an inorganic black pigment having a spectral reflectance of 15% or more at the wavelength, A coating composition for a detection target object for sensing using near-infrared light according to any one of claims 1 to 3.
The paint composition for detection objects for sensing using near-infrared light according to any one of claims 1 to 4, characterized in that the brightness of the formed coating film is 80 or less.
A coating film for a detection object for sensing using near-infrared light, characterized by having a near-infrared reflectance of 15% or more in the wavelength range of 800 to 2,500 nm.
A coating film for an object to be detected for sensing using near-infrared light, formed from the coating composition according to any one of claims 1 to 5.
　The coating film for a detection target object for sensing using near-infrared light according to claim 7, characterized by having a near-infrared reflectance of 15% or more in a wavelength range of 800 to 2,500 nm.
The object to be detected for sensing using near-infrared light according to any one of claims 6 to 8, characterized in that the spectral reflectance at a wavelength of 905 nm and/or 1,550 nm is 20% or more. coating film.
A detection target having a coating film formed using the coating composition for sensing detection targets according to any one of claims 1 to 5.
A traveling vehicle irradiates near-infrared light of a specific wavelength, reflects it on a detection target, detects the reflected light, and calculates the distance from the vehicle to the detection target based on the time it takes for the reflection. In the sensing method for measuring the distance between a vehicle and an object to be detected, the painted object is obtained by applying the paint composition according to any one of claims 1 to 5. , sensing method.
A moving vehicle irradiates near-infrared light with a specific wavelength, which is reflected on the detection target. The reflected light is detected, and the distance from the vehicle to the detection target is determined by the frequency difference between the emitted light and the reflected light. In the sensing method for measuring the distance between the vehicle and the object to be detected, the painted object is obtained by applying the paint composition according to any one of claims 1 to 5. A sensing method, characterized by: