Perylene black pigments with enhanced near-infrared-transparency properties

Abstract

The present invention relates to perylene pigments having an increased near-infrared (NIR) transparency, wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission Electron Microscopy (TEM).

Description

[0001] Perylene Black Pigments with Enhanced Near-Infrared-Transparency Properties

[0002] BACKGROUND OF THE INVENTION

[0003] Description of the State of the Art

[0004] For many plastic applications such as window framings, automotive interiors, and automotive exteriors, dark colors (black for example) are particularly desirable for aesthetic purposes. This is also true for many coating applications such as automotive coatings, aerospace coatings, industrial coatings, and architectural coatings.

[0005] Traditional black pigments such as carbon black, for example PBk 6 or PBk7, or inorganic black pigments like PBk 11 have been conventionally used for these applications. However, dark-colored plastics and coatings have historically been susceptible to the additional absorption of near-infrared radiation because they often rely on the use of pigments, such as carbon black, that absorb near-infrared radiation in addition to visible light.

[0006] Near-infrared (NIR) radiation, i.e., electromagnetic radiation having a wavelength of from 700 to 2500 nanometers, constitutes over 50 % of the solar energy that reaches the earth's surface. Heat is a direct consequence of the absorption of near-infrared (NIR) radiation. As a result, dark-colored plastics and coatings have historically been susceptible to substantially increased temperatures, particularly on sunny days and when exposed to sunlight, which is often undesirable for many reasons.

[0007] Additionally, recent advances have been made in technologies utilizing NIR, related to selfdriving ("autonomous") vehicles and other objects in a vehicle's surroundings including markings that are detectable by a sensor mounted on the autonomous vehicle. Traditional carbon black pigments strongly absorb near-infrared (NIR) Light Detection and Ranging (LiDAR) signals used by autonomous vehicles for navigation. Low LiDAR signal return erodes the object detection capability particularly for darker colored objects that contain higher levels of carbon black. Automotive coatings or automotive plastic exterior formulations using NIR-transparent or -reflective functional black pigments deliver superior signal response thereby improving object detection. Commonly, 905 nm and 1550 nm wavelengths of radiation are used for LiDAR detection.

[0008] Furthermore, laser-welding of plastic materials relies on the transparency and absorption of the pigments at the applied wavelength of the laser light. Commonly, 940 nm and 980 nm wavelengths of light from diode lasers are used for laser- welding. Therefore, the top-layer plastic needs to be transparent for the respective wavelengths. While this can be readily achieved for many light-colored plastics (e.g., green, red, blue, yellow), dark colors (e.g., black) pose a challenge as commonly used black pigments, such as PBk 6 or PBk 7, show strong absorption for NIR radiation making them unsuitable for the coloration of the top- layer plastics.

[0009] Also, mulch and protection films for agricultural applications, optical filters, and NIR- transparent components in security ink systems benefit from organic perylene black pigments with high NIR-transparency.

[0010] Another application field are automatized recycling processes for plastics. NIR spectroscopy can be used to quickly determine which types of plastic are present and offers many possible applications. However, one of the main problems is that it can be difficult to get accurate results if the plastic sample contains carbon black because carbon black absorbs NIR radiation. This can be overcome by using high-performance organic black perylene pigments instead of carbon black.

[0011] Many applications within the plastics or coatings industry require coloration with pigments that are transparent in the near-infrared (NIR) part of the electromagnetic spectrum to reduce the heat uptake upon exposure to sunlight, increase visibility for LiDAR systems, or enable laser-welding using lasers with NIR emission. This poses problems for black colors, as conventionally used pigments such as carbon black (for example, PBk 6 or PBk 7) strongly absorb NIR radiation. For such demanding industrial & commercial applications, modem organic pigments like high-performance organic black perylene pigments, e.g., PBk 31, PBk 32, Spectrasense Black K 0087 (Sun Chemical), and / or Spectrasense Black K 0088 (Sun Chemical), which are largely transparent to NIR radiation, may generally be used; however, without specific compositions and often additional processing steps, these supposedly high-performance pigments, and others, fail to exhibit the improved NIR transmittance properties of the present invention.

[0012] For example, WO 2005 / 078023 A2 refers to the synthesis and finish of selected perylene black pigments with the focus on black color in several application systems. While the pigments mentioned may be inherently NIR-transparent to some degree, the reference fails to teach perylene black pigments that achieve high levels of NIR transparency and / or methods of producing such pigments.

[0013] US 9,765,446 B2 refers to the use of NIR-transparent perylene black pigments in polyester to reduce the increase in temperature upon exposure to NIR-radiation, but it fails to teach perylene black pigments that achieve high levels of NIR transparency and / or methods of producing such pigments.

[0014] WO 2022 / 136308 Al and WO 2022 / 136310 Al both refer to solid solutions of NIR- transparent black perylene pigments and the production process thereof, but, again, neither document mentions the particle size distributions, which are necessary for highest levels of NIR transparency.

[0015] EP 2 883 919 Bl refers to a coating composition comprising two visibly absorbing and infrared transparent pigments, wherein the particle size of one of the pigments in the coating composition has a particle size under 100 nm while the other has a particle size of 200 nm or over. It does not mention particle size distributions, which are necessary for high levels of NIR transparency.

[0016] WO 2023 / 004855 Al refers to a black color paste based on black perylene pigments and polymers, and a preparation method thereof. This neither teaches the highly NIR transparent perylene black pigment compositions nor the methods required for creating them.

[0017] However, while the molecular makeup of these perylene black pigments allows for inherent transparency of NIR radiation, the observed NIR transparency for these pigments, and those referred to in the references above, is limited by their physical form obtained through conventional ways of finish, such as acid pasting or recrystallization in an organic solvent or mixture of water and an organic solvent after appropriate amorphization through, e.g., ball-milling, which processes lead to broad particle size distributions. The observed NIR transparency for these pigments is not satisfactory for all applications.

[0018] The object underlying the present invention is to provide perylene black pigments having a significant near-infrared (NIR) transmittance increase, preferably of at least 3.5 %, at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm in comparison with prior art perylene black pigments, as determined by optical spectroscopy (NIR transmittance)

[0019] According to the present invention, it was found that the NIR transparency of (high- performance) perylene black pigments can be notably improved over the current state-of- the-art pigments by adjusting and confining the particle size and particle size distribution to within specific ranges through means of comminution, comminution and recrystallization, or dissolution and precipitation. Surprisingly, this method is more effective for perylene black pigments of certain compositions.

[0020] The present invention demonstrates that by comminution, dissolution and precipitation, or comminution and recrystallization through, e.g., solvent- salt-kneading, wet-milling, or saltmilling the primary particle size can be adjusted to Dn(90) = 2 to 50 nm and the primary particle size distribution to span = 0.01 to 1.0; this was found to be a prerequisite for high transparency in the NIR part of the electromagnetic spectrum.

[0021] Comminution is the reduction of solid materials, in this case pigments, from one average particle size to a smaller average particle size. Methods of comminution comprise wet milling, ball milling, bead milling, vibration milling, planetary milling, jet milling, salt milling and attritor milling.

[0022] Comminution and recrystallization describes the reduction of solid materials, in this case pigments, from one average particle size to a smaller average particle size and a consecutive or simultaneous recrystallization of the particles in a suitable solvent or solvent mixture at temperatures between 0 °C and 300 °C. Modified pressure conditions above and below atmospheric (101.3 kPa) may be used for recrystallization, e.g., between 0.1 kPa to 3000 kPa, preferred 10 kPa to 2000 kPa, most preferred 100 kPa to 1000 kPa. Methods of comminution comprise wet milling, ball milling, bead milling, vibration milling, planetary milling and attritor milling and can be followed by a consecutive recrystallization (regrowth) of the particles in a suitable solvent. Methods in which comminution and recrystallization (regrowth) is performed simultaneously comprise solvent-salt-kneading.

[0023] Dissolution and precipitation describes the dissolution of the pigment or mixture of pigments in a suitable solvent followed by the dilution with a non-dissolving solvent leading to the precipitation of the pigment. Methods in which dissolution and precipitation is performed comprise acid pasting, high-turbulence drowning and nozzle -precipitation. High-turbulence drowning and nozzle -precipitation describe the method of dissolving the pigment or mixture of pigments in a suitable solvent such as sulfuric acid and spontaneously diluting the solution into a bath of water leading to precipitation of the pigment.

[0024] According to the present invention, it is preferred that the mechanical treatment (comminution) comprises one or more of kneading and milling, wherein kneading comprises a coextrusion, salt kneading, solvent- salt-kneading, single-shaft kneading and double-shaft kneading and wherein milling comprises wet milling, ball milling, bead milling, jet milling, vibration milling, planetary milling and attritor milling.

[0025] The perylene black pigments of the current invention with increased NIR transparency over current state-of-the-art perylene black pigments can, therefore, improve LiDAR detectability, reduce heat generation through NIR absorption, and enable laser-welding applications.

[0026] Citation or identification of any document in this application is not an admission that such represents prior art to the present invention.

[0027] DETAILED DESCRIPTION

[0028] The present invention is based on the finding that for select perylene black pigments, small particle sizes (e.g., Dn(90) = 2 to 50 nm) and narrow particle size distribution (e.g., span = 0.01 to 1.0) are responsible for or prerequisites to achieving notably improved near-infrared (NIR) transparency as compared to perylene black pigments not treated according to the present invention. Surprisingly, this method is more effective for certain perylene black pigment compositions.

[0029] A notable or significant increase of the near-infrared (NIR) transparency is preferably defined as a near- infrared (NIR) transmittance increase of at least 3.5 % transmittance, preferably 4 % transmittance, or more preferably 5 % transmittance, preferably for a sample prepared according to Reference Example 2 and analyzed according to Reference Example 3 over that of its Relevant Comparative Examples and / or perylene black pigments of a similar composition having a primary particle size outside the range of Dn(90) = 2 to 50 nm and / or outside the particle size distribution span = 0.01 to 1.0 (as determined by Transmission electron microscopy (TEM), preferably according to Reference Example 1) at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm.

[0030] Alternatively, a notable or significant increase of the near-infrared (NIR) transparency may be defined via % change, as calculated according to Reference Example 4, wherein the % change is at least 5 %, preferably 10 %, or more preferably 20 %, for a sample prepared according to Reference Example 2 and analyzed according to Reference Example 3 over that of its Relevant Comparative Examples and / or perylene black pigments of a similar composition having a primary particle size outside the range of Dn(90) = 2 to 50 nm and / or outside the particle size distribution span = 0.01 to 1.0 (as determined by Transmission electron microscopy (TEM), preferably according to Reference Example 1) at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm.

[0031] The present invention relates to a perylene black pigment, comprising or consisting of at least one compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, preferably comprising or consisting of at least one mixture and / or solid solution of one or more compounds of formula (I) and one or more compounds of formula (II);

[0032] wherein Ri and R2 are 4-methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl- C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halogen; wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission

[0033] Electron Microscopy (TEM). The invention also relates to a method of increasing the near-infrared (NIR) transparency of pigments described by the same formulae and to a process for preparing same by subjecting the compound, mixture and / or solid solution to a comminution, comminution and recrystallization, or dissolution and reprecipitation process; wherein after the comminution, comminution and recrystallization, or dissolution and reprecipitation process, the so obtained pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy (TEM).

[0034] Ri and R2 are 4-methoxybenzyl. R3 and R4 are, independently of one another, selected from phenylene, Cl-C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and / or naphthalenediyl. In another embodiment, R3 and R4 are, independently from one another, selected from the group consisting of phenylene, naphthalenediyl, and / or 3,4-Pyridinediyl. Xi to Xs are, independently from one another, selected from hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halide. In another embodiment, Xi to Xs are hydrogen (H). Preferably, R3 and R4 are attached to the remainder of formula (I) and / or (II) in such a way, that the 2 nitrogen atoms bound to R3 according to formulas (I) and (II) form a 5-membered or a 6- membered heterocycle with 2 atoms or 3 atoms of the heterocycle contributed by R3, preferably a (hetero) aromatic ring of R3, and the 2 nitrogen atoms bound to R4 according to formulas (I) and (II) form a 5-membered or a 6-membered heterocycle with 2 atoms or 3 atoms of the heterocycle contributed by R4, preferably a (hetero)aromatic ring of R4. In another embodiment, the 2 nitrogen atoms bound to R3 and / or R4 according to formulas (I) and (II) form a 5-membered heterocycle with 2 atoms of an aromatic ring of R3 and / or R4.

[0035] Solid solutions may be defined as a crystalline material, which consists of a host compound and one or more guest compounds that are incorporated in the crystal lattice of the host. Therefore, the solid solution is characterized by the crystal lattice of the host. Furthermore, for the purpose of the present application, mixed crystals may be defined as a crystalline material, which consists of two or more compounds and exhibits a crystal lattice that is different from the crystal lattices of the individual components (High Performance Pigments, ed. Hugh M. Smith, p. 296, Wiley-VCH Verlag-GmbH, 2002, ISBN 3-527- 30204-2). In the present application, a mixed crystal can be viewed as a type of solid solution.

[0036] The compounds of formula (I) and (II) are the product of the reaction of perylene-3,4:9,10- tetra-carboxylic acid dianhydride with aromatic diamines. Perylene-3,4:9,10-tetra- carboxylic acid dianhydride may be substituted in any of the 1-, 2-, 5-, 6-, 7-, 8-, 11- and 12-positions (Xi to Xs) with hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halide, independently from one another. Formula (I) and formula (II) are the cis- and transisomer with respect to each other. Conventionally, both isomers, formula (I) and formula (II), are formed in the manufacturing process.

[0037] The compound of formula (X) is the product of the reaction of perylene-3,4:9,10-tetra- carboxylic acid dianhydride with primary or secondary amines or aromatic monoamines.

[0038] The increased transparency in the near-infrared (NIR) part of the electromagnetic spectrum is achieved through adjustment or confinement of the primary particle size to Dn(90) = 2 to 50 nm and primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy, preferably according to Reference Example 1. In further embodiments, the primary particle size Dn(90) preferably is 2 to 45 nm, more preferably 2 to 40 nm, even more preferably 5 to 40 nm, or most preferably 10 to 40 nm and the primary particle size distribution span preferably is 0.05 to 1.0, more preferably 0.10 to 1.0, even more preferably 0.10 to 0.95, or most preferably 0.15 to 0.90 as determined by transmission electron microscopy, preferably according to Reference Example 1.

[0039] In further embodiments of the invention, the perylene black pigment of the present invention can be used for one or more of the following applications: coloring plastic articles which are used for laser penetration welding; as charge-generating material for electrophotography and as constituent of the black matrix in LCD displays, OLED displays, or any other type of display that requires black matrix; for preparing water-, polymer- or polyolefin wax based pigment preparations; and for coloring leather and leather-like materials. Comminution and recrystallization can be achieved, for example, by solvent-salt-kneading. Solvent- salt-kneading is carried out with an organic solvent wherein the at least one solvent is preferably one or more ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerine, triethylene glycol, dipropylene glycol, propylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water and dimethyl sulfoxide. The at least one solvent is more preferably one or more of diethylene glycol, diacetone alcohol, dimethylformamide, xylene, butanol, water and / or glycerine; or even more preferably one or more of diacetone alcohol, diethylene glycol and / or glycerine. Solvent- salt-kneading uses an inorganic salt as a grinding medium, one or more of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, any alkali metal halide, any alkaline earth metal halide, any alkali metal sulfate and any alkaline earth metal sulfate, preferably sodium chloride wherein, in one embodiment, the pigment to salt ratio (weight-% ratio) is between 1:2 and 1:18, preferably between 1:4 and 1:12, most preferably between 1:4 and 1:8. Alternatively, in another embodiment the weight ratio of one or more of sodium chloride, sodium sulfate and / or anhydrous aluminum sulfate relative to the mixture of pigments, synergists and / or additives, may be in the range 20:1 to 1:1, in another embodiment 15:1 to 2:1, in another embodiment 10:1 to 2:1, in another embodiment 8:1 to 2:1, in another embodiment 6:1 to 2:1, and in another embodiment 4:1 to 2:1. Solvent- salt-kneading is performed at temperatures between 25 °C and 120 °C, preferably between 40 °C and 100 °C, most preferably between 60 °C and 90 °C. Solvent- salt-kneading is carried out for 4 hours to 48 hours, preferably for 6 hours to 24 hours, most preferably for 8 hours to 18 hours. Solvent salt kneading can be carried out in the absence or presence of inorganic bases such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides or alkaline earth metal carbonates.

[0040] In one embodiment, the present invention includes the addition of one or more perylene synergists, for example, sulfonic acid derivatives and / or salts thereof; one or more quinacridone synergists, for example, sulfonic acid derivatives and / or salts thereof; one or more formaldehyde reaction products, for example, with 5,12-dihydroquino[2,3-b]acridine- 7, 14-dione and 3,5-dimethyl-lH-pyrazole; one or more formaldehyde reaction products, for example, with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and 3,5-dimethyl-lH-pyrazole sulfonated; one or more formaldehyde reaction products, for example, with 5,12- dihydroquino[2,3-b]acridine-7, 14-dione and phthalimide; one or more indanthrone (Pigment Blue 60) synergist, for example, sulfonic acid derivatives and / or salts thereof; one or more quinophthalone (Pigment Yellow 138) synergists, for example, sulfonic acid derivatives and / or salts thereof; one or more diketopyrrolopyrrole synergists; one or more natural or synthetic resins comprising esters and salts of abietic acid; one or more hydrogenated, partially hydrogenated, or dimerized rosins; one or more polysorbate-type nonionic surfactants comprising an ester or a mixture of esters formed from fatty acids, such as lauric or sebacic acid; and one or more polyols, such as sorbitic monolaureate or dibutylsebacate. The synergists, natural or synthetic resins, rosins, and other additives may be added either before and / or during and / or after kneading. The synergists, natural or synthetic resins, rosins, and other additives can be added in (total) amounts ranging from 0 to 20 weight- % relative to the pigment, preferably from 0 to 15 weight- % relative to the pigment, or more preferably from 0 to 10 weight- % relative to the pigment, which is 100 weight-%. If added, the minimum (total) amount of synergists, natural or synthetic resins, rosins, and other additives is 0.1 weight-%, preferably from 0.5 weight-%, more preferably 1.0 weight-% relative to the pigment, which is 100 weight-%.

[0041] After solvent- salt-kneading at appropriate conditions, the particles according to the invention have a primary particle size of Dn(90) = 2 to 50 nm and primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy, preferably according to Reference Example 1. According to the present invention, this leads to notably increased transparency in the NIR part of the electromagnetic spectrum over traditional pigments. This is exemplified by Inventive Example Al, Inventive Example A2 and Inventive Example A3 when compared to the Comparative Example A4, all of which are described by identical chemical formulae. Furthermore, this is exemplified by Inventive Example B 1 when compared to Comparative Example B2, which are both described by identical chemical formulae. Furthermore, this is exemplified by Inventive Example Cl when compared to Comparative Example C2, which are both described by identical chemical formulae. Furthermore, this is exemplified by Inventive Example DI when compared to Comparative Example D2, which are both described by identical chemical formulae. Furthermore, this is exemplified by Inventive Example El when compared to Comparative Example E2 which are both described by identical chemical formulae. It is noted that surprisingly only select compositions of perylene pigments are significantly affected by the comminution, comminution & recrystallization, and / or dissolution and reprecipitation processes presented herein; hence, only a minor increase of the transparency in the NIR part of the electromagnetic spectrum is achieved for other perylene black pigments as shown when Comparative Example Fl and Comparative Example F2 are compared to Comparative Example F3.

[0042] The present invention is further described by the following set of numbered embodiments and paragraphs and combinations of numbered embodiments and paragraphs resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of numbered embodiments or paragraphs is mentioned, for example in the context of a term such as "The method of one of numbered paragraphs 1 to 5", every numbered embodiment or paragraph in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to " The method of one of numbered embodiments or paragraphs 1, 2, 3, 4 and 5". Further, it is explicitly noted that the following set of numbered embodiments and paragraphs is not the set of claims determining the extent of protection but represents a suitably structured part of the description directed to general and specific aspects of the present invention. The features contained in the embodiments and paragraphs can be freely combined with each other without leaving the scope of the invention.

[0043] Embodiments

[0044] 1. A perylene black pigment, comprising or consisting of at least one compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, preferably comprising or consisting of at least one mixture and / or solid solution of one or more compounds of formula (I) and one or more compounds of formula (II); wherein Ri and R2 are 4-methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl- C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halogen; wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission Electron Microscopy (TEM).

[0045] 2. The perylene black pigment of embodiment 1, having a primary particle size Dn(90) = 2 to 45 nm, preferably Dn(90) = 2 to 40 nm, more preferably Dn(90) = 5 to 40 nm, most preferably Dn(90) = 10 to 40 nm.

[0046] 3. The perylene black pigment of embodiment 1 or 2, having a primary particle size distribution span = 0.05 to 1.0, preferably from 0.10 to 1.0, more preferably from 0.10 to 0.95, most preferably from 0.15 to 0.90. 4. The perylene black pigment of one of embodiments 1 to 3, wherein R3 and R4 are, independently from one another, selected from the group consisting of phenylene, naphthalenediyl, and 3,4-pyridinediyl.

[0047] 5. The perylene black pigment of one of embodiments 1 to 4, wherein Xi to Xs are hydrogen.

[0048] 6. The perylene black pigment of one of embodiments 1 to 5, further comprising one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, further additives, or combinations thereof.

[0049] 7. The perylene black pigment of embodiment 6, wherein the one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, further additives, or combinations thereof are present individually or in combination in amounts ranging from 0 to 20 weight- % relative to the pigment, preferably from 0 to 15 weight- % relative to the pigment, or most preferably from 0 to 10 weight-% relative to the pigment which is 100 weight- %.

[0050] 8. The perylene black pigment of embodiment 6 or 7, wherein the one or more synergists are selected from the group consisting of perylene synergists, quinacridone synergists, indanthrone (Pigment Blue 60) synergists, quinophthalone (Pigment Yellow 138) synergists, diketopyrrolopyrrole synergists, and combinations thereof.

[0051] 9. The perylene black pigment of one of embodiments 6 to 8, wherein the one or more resins are selected from the group consisting of natural resins, synthetic resins, and combinations thereof.

[0052] 10. The perylene black pigment of one of embodiments 6 to 9, wherein the one or more rosins are selected from the group consisting of hydrogenated rosins, partially hydrogenated rosins, dimerized rosins, and combinations thereof. 11. The perylene black pigment of one of embodiments 6 to 10, wherein the one or more surfactants are polysorbate-type nonionic surfactants comprising an ester or a mixture of esters formed from fatty acids.

[0053] 12. The perylene black pigment of embodiment 11, wherein the fatty acids are selected from the group consisting of lauric acid, sebacic acid, and combinations thereof.

[0054] 13. The perylene black pigment of one of embodiments 6 to 12, wherein the one or more polyols are selected from the group consisting of sorbitic monolaureate, dibutylsebacate, and combinations thereof.

[0055] 14. The perylene black pigment of one of embodiments 8 to 13, wherein the one or more perylene synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and combinations thereof.

[0056] 15. The perylene black pigment of one of embodiments 8 to 14, wherein the one or more quinacridone synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

[0057] 16. The perylene black pigment of one of embodiments 8 to 15, wherein the one or more formaldehyde reaction products are selected from the group consisting of: formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and 3,5-dimethyl-lH- pyrazole; formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14- dione and 3,5-dimethyl-lH-pyrazole sulfonated; and formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and phthalimide.

[0058] 17. The perylene black pigment of one of embodiments 8 to 16, wherein the one or more indanthrone (Pigment Blue 60) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

[0059] 18. The perylene black pigment of one of embodiments 8 to 17, wherein the one or more quinophthalone (Pigment Yellow 138) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof. 19. The perylene black pigment of one of embodiments 1 to 18, having a near- infrared (NIR) transmittance increase of at least 3.5 %, preferably at least 4 %, more preferably at least 5 %, most preferably at least 10%, specifically at least 20 %at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm in comparison with perylene black pigments having a primary particle size outside the range of Dn(90) = 2 to 50nm and / or outside the particle size distribution span = 0.01 to 1.0, as determined by Transmission Electron Microscopy (TEM).

[0060] 20. A process of preparing the perylene black pigment of one of embodiments 1 to 19, the process comprising: providing of at least one compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, preferably comprising or consisting of at least one mixture and / or solid solution of one or more compounds of formula (I) and one or more compounds of formula (II); a compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, wherein Ri and R2 are 4-methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl-C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halogen; wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission Electron Microscopy (TEM).

[0061] Subjecting the compound to a comminution, comminution and recrystallization, or dissolution and reprecipitation process; wherein after the comminution, comminution and recrystallization, or dissolution and reprecipitation process, the so obtained pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy (TEM).

[0062] 21. The process of embodiment 20, wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation processes involve the use of an organic solvent selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, glycerine, dimethylformamide, glycerine, triethylene glycol, dipropylene glycol, propylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, and dimethyl sulfoxide 22. The process of embodiment 20 or 21, wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation process is selected from the group consisting of solvent-salt-kneading, high turbulence drowning (nozzle precipitation), salt milling, wet milling, and ball milling.

[0063] 23. The process of one of embodiment 22 wherein the solvent- salt-kneading involves the use of an inorganic salt as a grinding medium.

[0064] 24. The process of embodiment 23, which is operated at a pigment:salt ratio between 1:2 and 1:18, preferably between 1:4 and 1:12, more preferably between 1:4 and 1:8.

[0065] 25. The process of one of embodiments 21 to 24, wherein the solvent-salt-kneading is performed at a temperature between 25 °C and 120 °C, preferably between 40 °C and 100 °C, more preferably between 60 °C and 90 °C.

[0066] 26. The process of one of embodiments 22 to 25, wherein the solvent-salt-kneading is carried out for 4 hours to 48 hours, preferably for 6 hours to 24 hours, more preferably for 8 hours to 18 hours.

[0067] 27. A coating, an ink, or a paint, comprising the perylene black pigment of one of embodiments 1 to 19 and / or a perylene black pigment, obtainable or obtained by the process according to one of embodiments 20 to 26.

[0068] 28. An article comprising the coating, the ink, or the paint of embodiment 27, wherein the coating, ink, or paint can be applied to one or more of plastics, glasses, silicatic layer systems, and organic -inorganic composites.

[0069] 29. The article of embodiment 28, which is a plastics article and / or an automotive coating.

[0070] 30. The use of the perylene black pigment of one of embodiments 1 to 19 and / or a perylene black pigment, obtainable or obtained by the process according to one of embodiments 20 to 26, in automotive coatings. 31. A method of increasing the near- infrared (NIR) transparency of perylene black pigments by employing the perylene black pigments of one of embodiments 1 to 19 and / or by preparing a perylene black pigment by the process according to one of embodiments 20 to 26 and / or subjecting the compound, mixture and / or solid solution of the perylene black pigment to a comminution, comminution and recrystallization, or dissolution and reprecipitation process.

[0071] Paragraphs

[0072] 1. A Perylene black pigment comprising: a compound of formula (X), formula (I), formula (II), or a mixture of formulas (I) and (II); wherein Ri and R2 are 4-Methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl-C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halide; wherein the perylene black pigment further comprises a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission electron microscopy (TEM) according to Reference Example

[0073] 1.

[0074] 2. The perylene black pigment of numbered paragraph 1 wherein the primary particle size Dn(90) = 2 to 45 nm, preferably Dn(90) = 2 to 40 nm, more preferably Dn(90) = 5 to 40 nm, or most preferably Dn(90) = 10 to 40 nm.

[0075] 3. The perylene black pigment of any preceding numbered paragraph wherein the primary particle size distribution span = 0.05 to 1.0, preferably from 0.10 to 1.0, more preferably from 0.10 to 0.95, or most preferably from 0.15 to 0.90.

[0076] 4. The perylene black pigment of any preceding numbered paragraph wherein R3 and R4 are, independently from one another, selected from the group consisting of Phenylene, Naphthalenediyl, and 3,4-Pyridinediyl.

[0077] 5. The perylene black pigment of any preceding numbered paragraph wherein Xi to Xs are H (hydrogen).

[0078] 6. The perylene black pigment of any preceding numbered paragraph further comprising one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, additives, and / or combinations thereof. 7. The perylene black pigment of numbered paragraph 6 wherein the one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, additives, and / or combinations thereof are present individually or in combination in amounts ranging from 0 to 20 weight- % relative to the pigment, preferably from 0 to 15 weight- % relative to the pigment, or most preferably from 0 to 10 weight-% relative to the pigment.

[0079] 8. The perylene black pigment of numbered paragraphs 6 or 7 wherein the one or more synergists are selected from the group consisting of perylene synergists, quinacridone synergists, indanthrone (Pigment Blue 60) synergists, quinophthalone (Pigment Yellow 138) synergists, diketopyrrolopyrrole synergists, and combinations thereof.

[0080] 9. The perylene black pigment of one of numbered paragraphs 6 to 8 wherein the one or more resins are selected from the group consisting of natural resins, synthetic resins, and / or combinations thereof.

[0081] 10. The perylene black pigment of one of numbered paragraphs 6 to 9 wherein the one or more rosins are selected from the group consisting of hydrogenated rosins, partially hydrogenated rosins, or dimerized rosins, and / or combinations thereof.

[0082] 11. The perylene black pigment of one of numbered paragraphs 6 to 10 wherein the one or more surfactants are polysorbate-type nonionic surfactants comprising an ester or a mixture of esters formed from fatty acids.

[0083] 12. The perylene black pigment of numbered paragraph 11 wherein the fatty acids are selected from the group consisting of lauric acid, sebacic acid, and / or combinations thereof.

[0084] 13. The perylene black pigment of one of numbered paragraphs 6 to 12 wherein the one or more polyols are selected from the group consisting of sorbitic monolaureate, dibutylsebacate, and / or combinations thereof.

[0085] 14. The perylene black pigment of one of numbered paragraphs 8 to 13 wherein the one or more perylene synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof. 15. The perylene black pigment of one of numbered paragraphs 8 to 14 wherein the one or more quinacridone synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

[0086] 16. The perylene black pigment of one of numbered paragraphs 8 to 15 wherein the one or more formaldehyde reaction products are selected from the group consisting of: formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and 3,5- dimethyl-lH-pyrazole; formaldehyde reaction products with 5,12-dihydroquino[2,3- b]acridine-7, 14-dione and 3,5-dimethyl-lH-pyrazole sulfonated; or formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and phthalimide.

[0087] 17. The perylene black pigment of one of numbered paragraphs 8 to 16 wherein the one or more indanthrone (Pigment Blue 60) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

[0088] 18. The perylene black pigment of one of numbered paragraphs 8 to 17 wherein the one or more quinophthalone (Pigment Yellow 138) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

[0089] 19. The perylene black pigment of any preceding numbered paragraph further comprising a near-infrared (NIR) transmittance increase of at least 3.5 %, preferably 4 %, or more preferably 5 %, for a sample prepared according to Reference Example 2 and analyzed according to Reference Example 3 over that of perylene black pigments having a primary particle size outside the range of Dn(90) = 2 to 50 nm and / or outside the particle size distribution span = 0.01 to 1.0 as determined by Transmission electron microscopy (TEM) according to Reference Example 1, at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm.

[0090] 20. The perylene black pigment of one of numbered paragraphs 1 to 18 further comprising a % Change of at least 5 %, preferably 10 %, or more preferably 20 %, as defined according to Reference Example 4, for a Sample prepared according to Reference Example 2 and analyzed according to Reference Example 3 over that of perylene black pigments having a primary particle size outside the range of Dn(90) = 2 to 50 nm and / or outside the particle size distribution span = 0.01 to 1.0 as determined by Transmission electron microscopy (TEM) according to Reference Example 1, at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm.

[0091] 21. A process of making a perylene black pigment, preferably of making the perylene black pigment of any preceding numbered paragraph, the process comprising: providing a pigment with a compound of formula (X), formula (I), formula (II), or a mixture of formulas (I) and (II); wherein Ri and R2 are 4-Methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl-C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halide; subjecting the pigment to a comminution, comminution and recrystallization, or dissolution and reprecipitation process; wherein after the comminution, comminution and recrystallization, or dissolution and reprecipitation process, the pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy (TEM) according to Reference Example 1.

[0092] 22. The process of numbered paragraph 21 wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation processes further comprises an organic solvent selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, glycerine, dimethylformamide, glycerine, triethylene glycol, dipropylene glycol, propylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, and dimethyl sulfoxide

[0093] 23. The process of numbered paragraph 21 or 22 wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation process is selected from the group consisting of solvent-salt-kneading, high turbulence drowning (nozzle precipitation), salt milling, wet milling, and ball milling.

[0094] 24. The process of one of numbered paragraphs 21 to 23 wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation process is solvent- salt-kneading further comprising an inorganic salt as a grinding medium.

[0095] 25. The process of numbered paragraph 24 further comprising a pigment: salt ratio between 1:2 and 1:18, preferably between 1:4 and 1:12, or more preferably between 1:4 and 1:8. 26. The process of one of numbered paragraphs 23 to 25 wherein the solvent- salt-kneading is performed at temperatures between 25 °C and 120 °C, preferably between 40 °C and 100 °C, or more preferably between 60 °C and 90 °C.

[0096] 27. The process of one of numbered paragraphs 23 to 26 wherein the solvent- salt-kneading is carried out for 4 hours to 48 hours, preferably for 6 hours to 24 hours, more preferably for 8 hours to 18 hours.

[0097] 28. A coating, ink, or paint comprising the perylene black pigment of one of numbered paragraphs 1 to 20.

[0098] 29. An article comprising the coating, ink, or paint of numbered paragraph 28 wherein the coating, ink, or paint may optionally be applied to plastics, glasses, silicatic layer systems, or organic -inorganic composites.

[0099] 30. A plastics article comprising the perylene black pigment of one of numbered paragraphs 1 to 20.

[0100] 31. A use of the perylene black pigment of one of numbered paragraphs 1 to 20 in automotive coatings.

[0101] The present invention has been described in detail, including various embodiments thereof. However, it will be appreciated that those skilled in the art, upon consideration of the present disclosure, may make modifications and / or improvements on this invention that fall within the scope and spirit of the invention.

[0102] EXAMPLES

[0103] The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended, nor should they be interpreted to, limit the scope of the invention. Compounds Used in Examples:

[0104] Compound 1 - (Spectrasense Black S 0084) as referred to in FR 2343012 Al, Example 1.

[0105] Compound 2 - (Spectrasense Black L 0086) as referred to in US 4,450,273, Example 1.

[0106] Compound 3 - (Spectrasense Black K 0087) as referred to in US 2010 / 0184983 Al, Example 1.

[0107] Compound 4 - (Spectrasense Black K 0088) as referred to in US 2010 / 0184983 Al, Example 6.

[0108] Compounds 1 and 2 correspond to the compound of formula (X).

[0109] Compounds 3 and 4 correspond to the compound of formula (I), the compound of formula (II), or a mixture of the compounds of formulas (I) and (II). Table 1. Compounds 1 to 4 and substituents Rl, R2, R3, R4, and XI to X8 as used in the Examples denoted by letters A, B, C, D, E, and F.

[0110] *Examples denoted by D and E comprise mixtures of Compound 3 and Compound 4 in different ratios; Examples denoted by D comprise a 50 / 50 ratio by weight of Compound 3 to Compound 4 while Examples denoted by E comprise a 75 / 25 ratio by weight of Compound 3 to Compound 4.

[0111] Table 1 describes the chemical structure of compounds 1 to 4 based on formulae (X), (I), and (II) as well as the corresponding substituents of Ri, R2, R3, R4, and Xi to Xs as used in the Inventive and Comparative Examples. See below for more details.

[0112] The following are descriptions of Inventive Examples and Comparative Examples. The consecutive naming A, B, C, D, E, and F indicates similar compositions of the respective Inventive Example and Comparative Example (see Table 1). Inventive Examples exhibit notably improved transmittance properties of at least 3.5 % transmittance or greater over their relevant Comparative Example at one or more of the wavelengths 905 nm, 940 nm, 980 nm, and 1550 nm when prepared according to Reference Example 2 and analyzed according to Reference Example 3 (e.g., A1-A3, Bl, Cl, DI, and El; data shown in Table 2). Comparative Examples were either products of similar compositions as the relevant Examples with the same letter (e.g., A, B, C, etc.) which did not undergo any comminution, comminution and recrystallization, and / or dissolution and reprecipitation processes presented herein (e.g., A4, B2, C2, D2, E2, and F3; data shown in Table 2); OR they underwent such processes and were not of the suitable perylene composition to be significantly affected by such processes, and, thus, they did not exhibit a notable transmittance increase of at least 3.5 % over their Relevant Comparative Example at one or more of the wavelengths 905 nm, 940 nm, 980 nm, and 1550 nm when prepared according to Reference Example 2 and analyzed according to Reference Example 3 (e.g., Fl and F2; data shown in Table 2). Inventive Example Al:

[0113] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 46.8 g of Compound 4 and 5.2g of Staybelite Resin-E. Then 208 g sodium chloride and 80 g of diacetone alcohol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet fdter cake was dried in a vacuum oven at 50 °C and 80 mbar for 24 h. The yield of the obtained black pigment was 47,0 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0114] Inventive Example A2:

[0115] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 46.8 g of Compound 4 and 5.2 g of Staybelite Resin-E. Then 208 g sodium chloride and 60 g of diethylene glycol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 70 °C. After 8 hours of kneading at 70°C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet filter cake was dried in a vacuum oven at 50 °C and 80 mbar for 24 h. The yield of the obtained black pigment was 48.0 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0116] Inventive Example A3:

[0117] A ball mill with a capacity of 0.9 litre was charged with 9.0 g of Compound 4, 0.35 g of dodecanol and 36.0 g of sodium chloride. Then 1.5 kg of steel balls (2.5 cm diameter) were added and the material was milled at 70 °C for 24 hours. Afterwards, the steel balls were removed and the material was dispersed in NaOH (aq) at pH=12. Then 0.9 g of rosin dissolved in NaOH (aq) were added and the mixture was stirred at 80 °C for 30 minutes. Next, 18 mL of 20 % HC1 (aq) were added and stirring was continued at 90 °C for 2 h. After cooling to room temperature, the mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet fdter cake was dried in a vacuum oven at 60 °C and 80 mbar for 24 h. The yield of the obtained black pigment was 9.9 g. The dry pigment was deagglomerated with an ultracentrifugal mill. Comparative Example A4:

[0118] Spectrasense Black K 0088 (Sun Chemical)

[0119] Inventive Example Bl:

[0120] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 46.8 g of Compound 3 and 5.2 g of Staybelite Resin-E. Then 208 g sodium chloride and 60 g of diacetone alcohol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet fdter cake was dried in a fluidized bed dryer at 80 °C for 3 h. The yield of the obtained black pigment was 42.0 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0121] Comparative Example B2:

[0122] Spectrasense Black K 0087 (Sun Chemical)

[0123] Inventive Example Cl:

[0124] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 28.9 g of Compound 2. Then 231 g sodium chloride and 90 g of diacetone alcohol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet fdter cake was dried in an oven at 80 °C for 24 h. The yield of the obtained black pigment was 50.6 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0125] Comparative Example C2:

[0126] Spectrasense Black L 0086 (Sun Chemical) Inventive Example DI:

[0127] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 23.4 g of Compound 3, 23.4 g of Compound 4 and 5.2 g of Staybelite Resin-E. Then 208 g sodium chloride and 60 g of diacetone alcohol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet filter cake was dried in a vacuum box dryer at 60 °C and 80 mbar for 24 h. The yield of the obtained black pigment was 48.5 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0128] Comparative Example D2:

[0129] 25 g of Spectrasense Black K 0087 (Sun Chemical) and 25 g of Spectrasense Black K 0088 were added to a plastic container and blended in a 3D shaker mixer for 30 minutes until a homogeneous mixture was obtained.

[0130] Inventive Example El:

[0131] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 35.1 g of Compound 3, 11.7 g of Compound 4 and 5.2 g of Staybelite Resin-E. Then 208 g sodium chloride and 60 g of diacetone alcohol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet filter cake was dried in a vacuum box dryer at 60 °C and 80 mbar for 24 h. The yield of the obtained black pigment was 48.0 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0132] Comparative Example E2:

[0133] 37.5 g of Spectrasense Black K 0087 (Sun Chemical) and 12.5 g of Spectrasense Black K 0088 were added to a plastic container and blended in a 3D shaker mixer for 30 minutes until a homogeneous mixture was obtained. Comparative Example Fl:

[0134] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 52.0 g of Compound 1. Then 208 g sodium chloride and 51 g of diethylene glycol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet filter cake was dried in an oven at 80 °C for 24 h. The yield of the obtained black pigment was 51.0 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0135] Comparative Example F2:

[0136] A kneading apparatus (Z-blade kneader) with capacity of 1.1 litre was charged with 37.1 g of Compound 1. Then 222 g sodium chloride and 50 g of diethylene glycol were added to the kneader and the rotary speed was set at 100 rpm. The walls of the apparatus were thermostated at 80 °C. After 8 hours of kneading at 80 °C the kneading was stopped. The kneading mass was added to 1500 g water and the mixture was stirred for 3 h. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was below 100 pS / cm. The wet fdter cake was dried in an oven at 80 °C for 24 h. The yield of the obtained black pigment was 50.8 g. The dry pigment was deagglomerated with an ultracentrifugal mill.

[0137] Comparative Example F3:

[0138] Spectrasense Black S 0084 (Sun Chemical)

[0139] Table 2. NIR transmittance in PVC at 0.5 % pigment concentration at selected wavelengths of 905 nm, 940 nm, 980 nm, and 1550 nm. Samples were prepared according to Reference Example 2 and analyzed according to Reference Example 3.

[0140] Table 2 shows that Inventive Examples Al, A2, A3, Bl, Cl, DI, and El display notably improved Near-infrared (NIR) radiation transparency of at least 3.5% transmittance or greater over their relevant comparative example of the same composition at one or more of the wavelengths 905 nm, 940 nm, 980 nm, and 1550 nm when applied in a PVC film (Reference Example 2) for transmittance testing (Reference Example 3). This can be seen by comparing % Transmittance at the individual wavelengths tested for: Inventive Examples Al, A2 and A3 with Comparative Example A4; Inventive Example Bl with Comparative Example B2; Inventive Example Cl with Comparative Example C2; Inventive Example DI with Comparative Example D2; and Inventive Example El with Comparative Example E2. For illustration, both Inventive Examples Al and A2 exhibit notably higher transparency at wavelengths 940nm, 980nm, and 1550 nm over Comparative Example A4, which is an indicator of improved properties (only required to have notably increased % Transmittance at one of the listed wavelengths in Table 2). It is noted that surprisingly only select compositions of perylene pigments are significantly affected by the comminution, comminution & recrystallization, and / or dissolution and reprecipitation processes presented herein; hence, Comparative Examples F1-F3 have been presented to demonstrate this point.

[0141] Table 3. % Change of Samples over Relevant Comparative Examples as calculated according to Reference Example 4.

[0142] Table 3 displays the relative % Change between the Samples over their Relevant Comparative Examples, as determined according to Reference Example 4. With this method, all Inventive Examples displayed a % Change value of at least 5 % or greater over their Relevant Comparative Example at one or more of the wavelengths 905 nm, 940 nm, 980 nm, and 1550 nm.

[0143] Table 4. Particle size distribution and distribution of inventive and comparative examples as analyzed according to Reference Example 1.

[0144] Table 4 shows that by application of the described finishing techniques, the particle size distributions of the Inventive Examples are significantly narrower (smaller span value as determined according to Reference Example 1) than their respective Comparative Examples, which did not undergo the comminution, comminution & recrystallization, and / or dissolution and reprecipitation processes presented herein. From the particle size data, even though the minimum particle size Dn(10) values display only a minor size shift, the larger particles denoted by the maximum particle size Dn(90) display a reduction by at least 20 % resulting in a much narrower particle size distribution denoted by the Span values.

[0145] TEST METHODS

[0146] Particle size distribution (according to the invention and according to Reference Example 1):

[0147] The particle size and particle size distribution has been determined using transmission electron microscopy (TEM). To determine the number-based particle size distribution, a small amount of the pigment samples was dispersed in ethanol and transferred to carbon- coated transmission electron microscopy grids. For example, a very small amount of the sample powder was transferred from the tip of a microspatula to a glass slide. It was wetted with 5 drops of ethanol and rubbed between another glass slide in order to distribute the pigment homogeneously. A carbon coated TEM grid (SF 162) was flat-dipped on the coated slide. After short drying in air the sample was then examined in a Zeiss Libra 120 transmission electron microscope, which is equipped with an omega filter operated at 120 kV in elastic lightfield mode at various magnifications at representative positions. Transmission electron microscopy images were obtained with the Zeiss LIBRA 120 transmission electron microscope with the aforementioned settings. The number-based particle size distribution was analyzed using the manual ImageJ NanoDefine ParticleSizer software. The guidelines described in DOI: 10.1039 / c8na00175h and DOI: 10.3390 / mal2142274 as well as DOI: 10.1787 / af5f9bda-en were applied. The span is defined as:

[0148] Sample preparation of a 0.5 weight- % Pigment Masstone in a polyvinyl chloride (PVC) film (Reference Example 2):

[0149] A polyvinyl chloride (PVC) film with a thickness of ~0.5 mm is produced on a twin-roll mill containing 0.5 weight-% of the pigment in a full shade application. The PVC material used is SorVyl DB 2105 transparent from Polymer-Chemie DE. A two roll mill type Collin 150 (Collin Lab & Pilot Solutions) was used at 150 °C applying a total milling time of ca. 10 min with a roll speed of 26 rpm and a friction of 20 %.

[0150] NIR transmission data (Reference Example 3):

[0151] NIR transmission data have been obtained using a spectrophotometer that measures the transmission characteristics of a sample across the UV, visible, and NIR parts of the electromagnetic spectrum. UV-Vis-NIR data has been determined using a Perkin Elmer Lambda 1050 spectrophotometer equipped with an 8 ° integrating sphere geometry. Data was collected across the wavelength range 300 to 2500 nm at 5 nm intervals. NIR transmission values at specific wavelengths relevant to industrial applications in the NIR wavelength range (905 nm, 940 nm, 980 nm, and 1550 nm) were chosen from this data. % Change Calculation (Reference Example 4):

[0152] The % Change data were calculated according to the following formula: where ° / oTFinalcorresponds to the % Transmittance value of a Sample prepared according to Reference Example 2 and analyzed according to Reference Example 3 at a given wavelength selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm, andQ / oTg rig ; na zcorresponds to % Transmittance value at the same wavelength of a

[0153] Relevant Comparative Example and / or perylene black pigments having a primary particle size outside the range of Dn(90) = 2 to 50 nm and / or outside the particle size distribution span = 0.01 to 1.0 (as determined by Transmission electron microscopy (TEM) according to Reference Example 1). %Transmittance data from Table 2 were used to generate the % Change data in Table 3. For example, to calculate the value shown in Table 3 for Inventive Example Al at 905 nm, values from Table 2 were used and the following calculation was performed:

[0154] Inventive Example

Claims

CLAIMS1. A perylene black pigment, comprising or consisting of at least one compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, preferably comprising or consisting of at least one mixture and / or solid solution of one or more compounds of formula (I) and one or more compounds of formula (II);wherein Ri and R2 are 4-methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl- C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl;wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halogen; wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission Electron Microscopy (TEM).

2. The perylene black pigment of claim 1, having a primary particle size Dn(90) = 2 to 45 nm, preferably Dn(90) = 2 to 40 nm, more preferably Dn(90) = 5 to 40 nm, most preferably Dn(90) = 10 to 40 nm.

3. The perylene black pigment of claim 1 or 2, having a primary particle size distribution span = 0.05 to 1.0, preferably from 0.10 to 1.0, more preferably from 0.10 to 0.95, most preferably from 0.15 to 0.90.

4. The perylene black pigment of one of claims 1 to 3, wherein R3 and R4 are, independently from one another, selected from the group consisting of phenylene, naphthalenediyl, and 3,4-pyridinediyl.

5. The perylene black pigment of one of claims 1 to 4, wherein Xi to Xs are hydrogen.

6. The perylene black pigment of one of claims 1 to 5, further comprising one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, further additives, or combinations thereof.

7. The perylene black pigment of claim 6, wherein the one or more synergists, resins, rosins, surfactants, polyols, formaldehyde reaction products, further additives, or combinations thereof are present individually or in combination in amounts ranging from 0 to 20 weight- % relative to the pigment, preferably from 0 to 15 weight- % relative to the pigment, or most preferably from 0 to 10 weight-% relative to the pigment which is 100 weight- %.

8. The perylene black pigment of claim 6 or 7, wherein the one or more synergists are selected from the group consisting of perylene synergists, quinacridone synergists,indanthrone (Pigment Blue 60) synergists, quinophthalone (Pigment Yellow 138) synergists, diketopyrrolopyrrole synergists, and combinations thereof.

9. The perylene black pigment of one of claims 6 to 8, wherein the one or more resins are selected from the group consisting of natural resins, synthetic resins, and combinations thereof.

10. The perylene black pigment of one of claims 6 to 9, wherein the one or more rosins are selected from the group consisting of hydrogenated rosins, partially hydrogenated rosins, dimerized rosins, and combinations thereof.

11. The perylene black pigment of one of claims 6 to 10, wherein the one or more surfactants are polysorbate-type nonionic surfactants comprising an ester or a mixture of esters formed from fatty acids.

12. The perylene black pigment of claim 11, wherein the fatty acids are selected from the group consisting of lauric acid, sebacic acid, and combinations thereof.

13. The perylene black pigment of one of claims 6 to 12, wherein the one or more polyols are selected from the group consisting of sorbitic monolaureate, dibutylsebacate, and combinations thereof.

14. The perylene black pigment of one of claims 8 to 13, wherein the one or more perylene synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and combinations thereof.

15. The perylene black pigment of one of claims 8 to 14, wherein the one or more quinacridone synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

16. The perylene black pigment of one of claims 8 to 15, wherein the one or more formaldehyde reaction products are selected from the group consisting of: formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and 3,5-dimethyl-lH-pyrazole; formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14- dione and 3,5-dimethyl-lH-pyrazole sulfonated; and formaldehyde reaction products with 5, 12-dihydroquino[2,3-b]acridine-7, 14-dione and phthalimide.

17. The perylene black pigment of one of claims 8 to 16, wherein the one or more indanthrone (Pigment Blue 60) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

18. The perylene black pigment of one of claims 8 to 17, wherein the one or more quinophthalone (Pigment Yellow 138) synergists are selected from the group consisting of sulfonic acid derivatives, salts thereof, and / or combinations thereof.

19. The perylene black pigment of one of claims 1 to 18, having a near-infrared (NIR) transmittance increase of at least 3.5 %, preferably at least 4 %, more preferably at least 5 %, most preferably at least 10%, specifically at least 20 %at one or more wavelengths selected from the group consisting of 905 nm, 940 nm, 980 nm, and 1550 nm in comparison with perylene black pigments having a primary particle size outside the range of Dn(90) = 2 to 50nm and / or outside the particle size distribution span = 0.01 to 1.0, as determined by Transmission Electron Microscopy (TEM).

20. A process of preparing the perylene black pigment of one of claims 1 to 19, the process comprising: providing of at least one compound of formula (X), formula (I), formula (II), or a mixture of two or more thereof, preferably comprising or consisting of at least one mixture and / or solid solution of one or more compounds of formula (I) and one or more compounds of formula (II);wherein Ri and R2 are 4-methoxybenzyl; wherein R3 and R4 are independently selected from the group consisting of phenylene, Cl- C5-alkylphenylene, Cl-C5-alkoxyphenylene, hydroxyphenylene, halogenated phenylene, pyridinediyl, Cl-C5-alkylpyridinediyl, Cl-C5-alkoxy-pyridinediyl, halogenated pyridinediyl, anthraquinonediyl, and naphthalenediyl; wherein Xi to Xs are independently selected from the group consisting of hydrogen, C1-C5 alkyl, C1-C5 alkoxy, hydroxy, phenyl, or halogen; wherein the perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by Transmission Electron Microscopy (TEM). subjecting the compound, mixture and / or solid solution to a comminution, comminution and recrystallization, or dissolution and reprecipitation process; wherein after the comminution, comminution and recrystallization, or dissolution and reprecipitation process, the so obtained perylene black pigment has a primary particle size Dn(90) = 2 to 50 nm and a primary particle size distribution span = 0.01 to 1.0 as determined by transmission electron microscopy (TEM).

21. The process of claim 20, wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation processes involve the use of an organic solvent selectedfrom the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, glycerine, dimethylformamide, glycerine, triethylene glycol, dipropylene glycol, propylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, and dimethyl sulfoxide.

22. The process of claim 20 or 21, wherein the comminution, comminution and recrystallization, or dissolution and reprecipitation process is selected from the group consisting of solvent-salt-kneading, high turbulence drowning (nozzle precipitation), salt milling, wet milling, and ball milling.

23. The process of one of claim 22 wherein the solvent- salt-kneading involves the use of an inorganic salt as a grinding medium.

24. The process of claim 23, which is operated at a pigment:salt weight ratio between 1:2 and 1:18, preferably between 1:4 and 1:12, more preferably between 1:4 and 1:8.

25. The process of one of claims 21 to 24, wherein the solvent- salt-kneading is performed at a temperature between 25 °C and 120 °C, preferably between 40 °C and 100 °C, more preferably between 60 °C and 90 °C.

26. The process of one of claims 22 to 25, wherein the solvent- salt-kneading is carried out for 4 hours to 48 hours, preferably for 6 hours to 24 hours, more preferably for 8 hours to 18 hours.

27. A coating, an ink, or a paint, comprising the perylene black pigment of one of claims 1 to 19 and / or a perylene black pigment, obtainable or obtained by the process according to one of claims 20 to 26.

28. An article comprising the coating, the ink, or the paint of claim 27, wherein the coating, ink, or paint can be applied to one or more of plastics, glasses, silicatic layer systems, and organic -inorganic composites.

29. The article of claim 28, which is a plastics article and / or an automotive coating.

30. The use of the perylene black pigment of one of claims 1 to 19 and / or a perylene black pigment, obtainable or obtained by the process according to one of claims 20 to 26, in automotive coatings.

31. A method of increasing the near- infrared (NIR) transparency of perylene black pigments by employing the perylene black pigments of one of claims 1 to 19 and / or by preparing a perylene black pigment by the process according to one of claims 20 to 26 and / or subjecting the compound, mixture and / or solid solution of the perylene black pigment to a comminution, comminution and recrystallization, or dissolution and reprecipitation process.

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