CN114644858A

CN114644858A - Pigment dispersion liquid, coloring composition, and method for dispersing pigment

Info

Publication number: CN114644858A
Application number: CN202111265466.0A
Authority: CN
Inventors: 野田国宏; 千坂博树; 盐田大
Original assignee: Tokyo Ohka Kogyo Co Ltd
Current assignee: Tokyo Ohka Kogyo Co Ltd
Priority date: 2020-12-18
Filing date: 2021-10-28
Publication date: 2022-06-21
Also published as: KR20220088334A; TW202229474A; JP2022097131A

Abstract

The present invention relates to a pigment dispersion liquid, a coloring composition, and a method for dispersing a pigment. The present invention provides a pigment dispersion liquid which contains a well-dispersed pigment and provides a coloring composition capable of forming a colored molded body with excellent heat resistance. Further, it is an object to provide a colored composition which provides a colored molded article having excellent heat resistance. Further, an object of the present invention is to provide a pigment dispersion method capable of dispersing a pigment well and stably in a short time and capable of producing a pigment dispersion liquid that provides a colored composition capable of forming a colored molded article having excellent heat resistance. In the pigment dispersion liquid, a pigment is dispersed in an aprotic polar solvent using a polyamic acid containing at least one of a partial skeleton derived from an aromatic diamine having a specific structure and a partial skeleton derived from an alicyclic tetracarboxylic dianhydride having a specific structure.

Description

Pigment dispersion liquid, coloring composition, and method for dispersing pigment

Technical Field

The present invention relates to a pigment dispersion liquid, a coloring composition containing the pigment dispersion liquid, and a method for dispersing a pigment.

Background

Conventionally, pigment dispersions containing various pigments have been used for coloring liquid compositions such as inks and various resin compositions. As a representative pigment, for example, carbon black can be cited. The composition colored by using the carbon black dispersion is used not only for printing and coating applications but also as a material for forming a light-shielding material such as a black matrix or a black column spacer in various display panels.

A pigment dispersion such as a carbon black dispersion is often produced by dispersing a pigment in a solvent such as an organic solvent using a dispersant. As a method for producing such a pigment dispersion, for example, the following methods are known as a method for producing a carbon black dispersion: carbon black is dispersed in an organic solvent such as an alcohol, a glycol-based solvent, a ketone, or an aprotic polar organic solvent using a low-molecular-weight compound such as an organic dye derivative or a triazine derivative as a dispersant (patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-213405

Disclosure of Invention

Problems to be solved by the invention

However, the method described in patent document 1 has the following problems due to the combination of the dispersant and the organic solvent: the pigment is not well and stably dispersed; alternatively, a very long time is required for the pigment to be well dispersed. Further, when the carbon black obtained by the method described in patent document 1 is used for coloring various compositions, there is a problem that the heat resistance of the black composition obtained by using a dispersant having poor heat resistance is also poor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pigment dispersion liquid containing a pigment dispersed well and stably and capable of providing a colored composition capable of forming a colored molded article having excellent heat resistance. Further, an object of the present invention is to provide a pigment composition which provides a colored molded article having excellent heat resistance. Further, an object of the present invention is to provide a pigment dispersion method capable of dispersing a pigment well and stably in a short time and capable of producing a pigment dispersion liquid that provides a colored composition capable of forming a colored molded article having excellent heat resistance.

Means for solving the problems

The present inventors have found that the above problems can be solved by dispersing a pigment in an aprotic polar solvent using a polyamic acid containing at least one of a partial skeleton derived from an aromatic diamine having a specific structure and a partial skeleton derived from an alicyclic tetracarboxylic dianhydride having a specific structure in a pigment dispersion liquid, and have completed the present invention.

The invention according to claim 1 is a pigment dispersion liquid containing a pigment, a polyamic acid, and an aprotic polar organic solvent,

the content of the pigment in the solid content is 40 to 99 mass%,

the polyamic acid includes a structural unit represented by the following formula (a1),

[ chemical formula 1]

(in the formula (a1), A¹Is a tetravalent organic radical, A²Is a divalent organic group. )

Wherein A is¹Is a group represented by the following formula (a2),

[ chemical formula 2]

(in the formula (a2), R^a11、R^a12And R^a13Each independently represents 1 selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and a fluorine atom, and a is an integer of 0 to 12. )

Or, A²Is a group represented by the following formula (a3),

-Ar¹-X-Ar²-···(a3)

(in the formula (a3), Ar¹And Ar²Each independently is phenylene which may have a substituent orNaphthylene, X is-CO-NH-. ).

The invention of claim 2 is a coloring composition comprising a base component and the pigment dispersion liquid according to claim 1,

the content of the pigment in the solid content is 0.1 mass% or more and less than 50 mass%.

The 3 rd embodiment of the present invention is a method for dispersing a pigment, comprising the steps of:

mixing a pigment and a polyamic acid in a dispersion medium containing an aprotic polar organic solvent so that the content of the pigment in the solid content is 40 to 99 mass%, and then dispersing the pigment in the dispersion medium,

[ chemical formula 3]

Wherein A is¹Is a group represented by the following formula (a2),

[ chemical formula 4]

Or, A²Is a group represented by the following formula (a3),

-Ar¹-X-Ar²-···(a3)

(in the formula (a3), Ar¹And Ar²Each independently is phenylene or naphthylene which may have a substituent, and X is-CO-NH-. ).

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a pigment dispersion liquid containing a pigment dispersed well and stably and a colored composition capable of forming a colored molded article having excellent heat resistance can be provided. Further, according to the present invention, a colored composition which provides a colored molded article having excellent heat resistance can be provided. Further, according to the present invention, a pigment dispersion method capable of well and stably dispersing a pigment in a short time and capable of producing a pigment dispersion liquid that provides a colored composition capable of forming a colored molded article having excellent heat resistance can be provided.

Detailed Description

Pigment Dispersion

The pigment dispersion liquid contains a pigment, a polyamic acid, and an aprotic polar organic solvent. The content of the pigment in the solid content of the pigment dispersion is 40 mass% or more and 99 mass% or less, preferably 40 mass% or more and 90 mass% or less, and more preferably 40 mass% or more and 80 mass% or less. The components essential to or optionally contained in the pigment dispersion liquid will be described in order below.

[ pigment ]

The pigment is not particularly limited, and various pigments can be used. The pigment may be an inorganic pigment or an organic pigment.

The Pigment is not particularly limited, and for example, a compound classified as a Pigment (Pigment) in a color index (C.I.; issued by The Society of Dyers and Colourists company), specifically, a compound to which a color index (C.I.) number described below is attached, is preferably used.

Examples of a yellow pigment that can be preferably used include c.i. pigment yellow 1 (hereinafter, simply referred to as "c.i. pigment yellow"), 3, 11, 12, 13, 14, 15, 16, 17, 20, 24, 31, 53, 55, 60, 61, 65, 71, 73, 74, 81, 83, 86, 93, 95, 97, 98, 99, 100, 101, 104, 106, 108, 109, 110, 113, 114, 116, 117, 119, 120, 125, 126, 127, 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 156, 166, 167, 168, 175, 180, and 185.

Examples of orange pigments that can be preferably used include c.i. pigment orange 1 (hereinafter, also referred to as "c.i. pigment orange" simply as a reference), 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 55, 59, 61, 63, 64, 71, and 73.

Examples of the violet pigment that can be preferably used include c.i. pigment violet 1 (hereinafter, also referred to as "c.i. pigment violet", and only the reference numeral), 19, 23, 29, 30, 32, 36, 37, 38, 39, 40, and 50.

Examples of red pigments that can be preferably used include c.i. pigment red 1 (hereinafter, also referred to as "c.i. pigment red" simply by reference numeral) 2,3, 4, 5, 6, 7, 8, 9,10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48: 1. 48: 2. 48: 3. 48: 4. 49: 1. 49: 2. 50: 1. 52: 1. 53: 1. 57 and 57: 1. 57: 2. 58: 2. 58: 4. 60: 1. 63: 1. 63: 2. 64: 1. 81: 1. 83, 88, 90: 1. 97, 101, 102, 104, 105, 106, 108, 112, 113, 114, 122, 123, 144, 146, 149, 150, 151, 155, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 180, 185, 187, 188, 190, 192, 193, 194, 202, 206, 207, 208, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 242, 243, 245, 254, 255, 264, and 265.

Examples of blue pigments that can be preferably used include c.i. pigment blue 1 (hereinafter, also referred to as "c.i. pigment blue" and simply referred to as "c.i. pigment blue"), 2, 15, and 15: 3. 15: 4. 15: 6. 16, 22, 28, 60, 64, and 66 are exemplified.

Examples of pigments having a hue other than those described above which can be preferably used include green pigments such as c.i. pigment green 7, c.i. pigment green 36 and c.i. pigment green 37, brown pigments such as c.i. pigment brown 23, c.i. pigment brown 25, c.i. pigment brown 26 and c.i. pigment brown 28, white pigments such as c.i. pigment white 4, c.i. pigment white 5, c.i. pigment white 6 and c.i. pigment white 7, and black pigments such as c.i. pigment black 1 and c.i. pigment black 7.

In addition, the pigment may be a light-screening agent exhibiting a black color or a hue close to black. A pigment dispersion liquid containing a light-shading agent can be suitably used for the preparation of a coloring composition for the formation of a black matrix or a black columnar spacer in a liquid crystal display panel, the formation of a bank for the division of a light-emitting layer in an organic EL element.

As the light-shading agent for the pigment, a black pigment or a violet pigment is preferably used. As the black pigment or the violet pigment, various pigments (both organic and inorganic) can be used. Examples of the black pigment and the violet pigment include carbon black, perylene pigments, lactam pigments, titanium blacks such as titanium oxynitride and titanium nitride, metal oxides, composite oxides, metal sulfides, metal sulfates, and metal carbonates. Examples of the metal constituting the metal oxide, metal composite oxide, metal sulfide, metal sulfate, or metal carbonate include copper, iron, manganese, cobalt, tungsten, chromium, nickel, zinc, calcium, and silver.

Among the above light-shading agents, carbon black is preferred in view of easy availability and excellent light-shading properties. As the carbon black, known carbon blacks such as channel black, furnace black, thermal black, and lamp black can be used. In addition, carbon black coated with a resin may also be used.

Carbon black subjected to treatment for introducing an acidic group is also preferable. The acidic group introduced into the carbon black is a functional group showing acidity based on the definition of bronsted. Specific examples of the acidic group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group. The acidic group introduced into the carbon black may form a salt. The cation forming a salt with an acidic group is not particularly limited within a range not interfering with the object of the present invention. Examples of the cation include various metal ions, cations of nitrogen-containing compounds, ammonium ions, and the like, and preferably alkali metal ions such as sodium ions, potassium ions, and lithium ions, and ammonium ions.

Among the carbon blacks subjected to the treatment of introducing an acidic group described above, carbon blacks having 1 or more functional groups selected from the group consisting of a carboxylic acid group, a carboxylate group, a sulfonic acid group, and a sulfonate group are preferable from the viewpoint of achieving high electrical resistance of the light-shielding cured film formed using the coloring composition.

The method for introducing an acidic group into carbon black is not particularly limited. Examples of the method for introducing an acidic group include the following methods.

Method 1): sulfonic acid groups are introduced into carbon black by a direct substitution method (which uses concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid, etc.) or an indirect substitution method (which uses sulfite, bisulfite, etc.).

Method 2): an organic compound having an amino group and an acidic group is subjected to diazo coupling with carbon black.

Method 3): an organic compound having a halogen atom and an acidic group is reacted with carbon black having a hydroxyl group by Williamson etherification.

Method 4): an organic compound having a halocarbonyl group and an acidic group protected by a protecting group is reacted with carbon black having a hydroxyl group.

Method 5): an organic compound having a halocarbonyl group and an acid group protected by a protecting group is used to perform a Friedel-crafts reaction on carbon black, followed by deprotection.

Among the above methods, method 2) is preferred in view of ease of treatment for introducing an acidic group and safety. As the organic compound having an amino group and an acidic group used in the method 2), a compound in which an amino group and an acidic group are bonded to an aromatic group is preferable. Examples of such a compound include aminobenzenesulfonic acid such as sulfanilic acid and aminobenzoic acid such as 4-aminobenzoic acid.

The number of moles of the acidic groups introduced into the carbon black is not particularly limited within a range not interfering with the object of the present invention. The number of moles of the acidic groups introduced into the carbon black is preferably 1mmol to 200mmol, more preferably 5mmol to 100mmol, per 100g of the carbon black.

The carbon black may be coated with a resin. The coating treatment with the resin may be performed on carbon black into which an acidic group has been introduced. When a coloring composition containing a colorant dispersion liquid containing resin-coated carbon black is used, a colored molded article having excellent light-shielding properties and insulating properties and low surface reflectance can be easily formed.

The coating treatment with the resin does not particularly adversely affect the dielectric constant of a light-shielding colored molded article formed using the colored composition. Examples of resins that can be used for coating carbon black include: thermosetting resins such as phenol resins, melamine resins, xylene resins, diallyl phthalate resins, glyphosate (glyphosate) resins, epoxy resins, and alkylbenzene resins; thermoplastic resins such as polystyrene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, modified polyphenylene ether, polysulfone, poly (p-phenylene terephthalamide), polyamideimide, polyimide, polyaminobismaleimide, polyether sulfone, polyphenylene sulfone, polyarylate, and polyether ether ketone. The amount of resin coating on the carbon black is preferably 1 mass% to 30 mass% with respect to the total of the mass of the carbon black and the mass of the resin.

The carbon black may be treated with a silane coupling agent for the purpose of improving adhesion between a colored molded article formed using a colored composition containing carbon black and various substrates. The treatment with the silane coupling agent may be performed before or after the treatment of introducing an acidic group into the carbon black, or may be performed before or after the dispersion treatment using a polyamic acid as a dispersant.

The silane coupling agent used for the treatment of carbon black can be appropriately selected from conventionally known silane coupling agents. The silane coupling agent used for the treatment of carbon black is preferably a silane coupling agent represented by the following formula (I).

R^A1 _aR^A2 _(3-a)Si-R^A3-NH-C(O)-Y-R^A4-X···(I)

(in the formula (I), R^A1Is alkoxy, R^A2Is alkyl, a is an integer of 1 to 3, R^A3Is alkylene, Y is-NH-, -O-, or-S-, R^A4Is a single bond or alkylene, X is a monocyclic or polycyclic nitrogen-containing heteroaryl group which may have a substituent, and-Y-R in X^A4-the bonded ring is a nitrogen-containing 6-membered aromatic ring, -Y-R^A4-to a carbon atom of the above nitrogen-containing 6-membered aromatic ring. )

In the formula (I), R^A1Is an alkoxy group. With respect to R^A1The number of carbon atoms of the alkoxy group is preferably 1 to 6, more preferably 1 to 4, and particularly preferably 1 or 2 from the viewpoint of reactivity of the silane coupling agent. As R^A1Preferable specific examples thereof include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group and n-hexoxy group. Among these alkoxy groups, methoxy and ethoxy are preferable.

R as alkoxy^A1The silanol group formed by hydrolysis reacts with a functional group containing an active hydrogen atom, such as a hydroxyl group or a carboxyl group, present on the surface of the carbon black, whereby the silane coupling agent is bonded to the surface of the carbon black. Therefore, a is preferably 3 from the viewpoint of facilitating bonding of the silane coupling agent to the surface of the carbon black.

In the formula (I), R^A2Is an alkyl group. With respect to R^A2The number of carbon atoms of the alkyl group is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 or 2 from the viewpoint of reactivity of the silane coupling agent. As R^A2Preferable specific examples of (a) include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl.

In the formula (I), R^A3Is an alkylene group. With respect to R^A3The number of carbon atoms of the alkylene group is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 2 to 4. As R^A3Preferable specific examples thereof include methylene, 1, 2-ethylene, 1-ethylene, propane-1, 3-diyl, propane-1, 2-diyl, propane-1, 1-diyl, propane-2, 2-diyl, butane-1, 4-diyl, butane-1, 3-diyl and butane-1,2-diyl, butane-1, 1-diyl, butane-2, 2-diyl, butane-2, 3-diyl, pentane-1, 5-diyl, pentane-1, 4-diyl, and hexane-1, 6-diyl, heptane-1, 7-diyl, octane-1, 8-diyl, nonane-1, 9-diyl, decane-1, 10-diyl, undecane-1, 11-diyl, and dodecane-1, 12-diyl. Of these alkylene groups, 1, 2-ethylene, propane-1, 3-diyl and butane-1, 4-diyl are preferable.

Y is-NH-, -O-, or-S-, preferably-NH-. The reason for this is that the bond represented by-CO-NH-is less susceptible to hydrolysis than the bond represented by-CO-O-or-CO-S-. In the carbon black obtained by treating a compound in which Y is — NH "as a silane coupling agent, the structure of the silane coupling agent is not easily changed by the action of an acid, a base, or the like, and thus a desired effect by the use of the silane coupling agent can be easily obtained.

R^A4Is a single bond or an alkylene group, preferably a single bond. R is^A4Preferred examples of alkylene radicals and R^A3The same is true.

X is a monocyclic or polycyclic nitrogen-containing heteroaryl group which may have a substituent, and-Y-R in X^A4-the bonded ring is a nitrogen-containing 6-membered aromatic ring, -Y-R^A4-to a carbon atom in the nitrogen-containing 6-membered aromatic ring. The reason is not clear, and when a colored composition containing a compound having such X as a silane coupling agent is used, a colored molded article having excellent adhesion to a base material, water resistance, and solvent resistance can be formed.

When X is a polycyclic heteroaryl group, the heteroaryl group may be a group in which a plurality of monocyclic rings are condensed or a group in which a plurality of monocyclic rings are bonded to each other through a single bond. When X is a polycyclic heteroaryl group, the number of rings included in the polycyclic heteroaryl group is preferably 1 to 3. When X is a polycyclic heteroaryl group, the ring fused or bonded to the nitrogen-containing 6-membered aromatic ring in X may or may not contain a heteroatom, and may or may not be an aromatic ring.

Examples of the substituent that X of the nitrogen-containing heteroaryl group may have include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aliphatic acyl group having 2 to 6 carbon atoms, a benzoyl group, a nitro group, a nitroso group, an amino group, a hydroxyl group, a mercapto group, a nitrile group, a sulfonic acid group, a carboxyl group, a halogen atom, and the like. The number of the substituents which X has is not particularly limited within a range not interfering with the object of the present invention. The number of substituents of X is preferably 5 or less, more preferably 3 or less. When X has a plurality of substituents, the plurality of substituents may be the same or different.

Preferred examples of X include groups represented by the following formulae.

[ chemical formula 5]

Among the above groups, a group of the following formula is more preferable as X.

[ chemical formula 6]

Preferred specific examples of the compound represented by the formula (I) described above include the following compounds 1 to 8.

[ chemical formula 7]

The method of treating the carbon black with the silane coupling agent is not particularly limited, and the treatment with the silane coupling agent is carried out according to a known method. Typically, the following methods are preferred: the carbon black is reacted with a silane coupling agent in the presence of water in an organic solvent in which the silane coupling agent is soluble.

The amount of the silane coupling agent used is not particularly limited as long as the desired effect can be obtained. The amount of the silane coupling agent used is preferably 0.5 parts by mass or more and 15 parts by mass or less, and more preferably 3 parts by mass or more and 7 parts by mass or less, with respect to 100 parts by mass of carbon black.

The treatment of carbon black with a silane coupling agent is carried out in the presence of water. Water may be added to the treatment liquid containing the carbon black and the silane coupling agent, but it is not necessary to add water to the treatment liquid. When the treatment with the silane coupling agent is performed in an air atmosphere containing sufficient moisture, the alkoxy group of the silane coupling agent is hydrolyzed by the moisture in the air to form a silanol group.

The temperature at which the carbon black is treated with the silane coupling agent is not particularly limited as long as the reaction between the silane coupling agent and the carbon black is favorably performed. The treatment of carbon black with the silane coupling agent is typically carried out at a temperature of 25 ℃ to 100 ℃.

In addition, perylene pigments are also preferred as pigments. Specific examples of the perylene pigment include a perylene pigment represented by the following formula (A-1), a perylene pigment represented by the following formula (A-2), and a perylene pigment represented by the following formula (A-3). Of commercially available products, perylene pigments such as K0084 and K0086, pigment Black 21, 30, 31, 32, 33 and 34 manufactured by BASF corporation are preferably used.

[ chemical formula 8]

In the formula (A-1), R^A11And R^A12Each independently represents an alkylene group having 1 to 3 carbon atoms, R^A13And R^A14Each independently represents a hydrogen atom, a hydroxyl group, a methoxy group, or an acetyl group.

[ chemical formula 9]

In the formula (A-2), R^A15And R^A16Each independently represents an alkylene group having 1 to 7 carbon atoms.

[ chemical formula 10]

In the formula (A-3), R^A17And R^A18Each independently represents a hydrogen atom or an alkyl group having 1 to 22 carbon atoms, and may contain a heteroatom such as N, O, S or P. R^A17And R^A18In the case of an alkyl group, the alkyl group may be linear or branched.

The compound represented by the above formula (A-1), the compound represented by the formula (A-2) and the compound represented by the formula (A-3) can be synthesized, for example, by the methods described in Japanese patent laid-open Nos. 62-1753 and 63-26784. Namely, perylene-3, 5,9, 10-tetracarboxylic acid or dianhydride thereof and amine are used as raw materials, and the reaction is carried out in water or an organic solvent by heating. Then, the obtained crude product is reprecipitated in sulfuric acid, or recrystallized in water, an organic solvent, or a mixed solvent thereof, to obtain a target product.

In order to disperse the perylene pigment in the colorant dispersion liquid well, the average particle diameter of the perylene pigment is preferably 10nm or more and 1000nm or less.

The light-shading agent may contain a lactam pigment. Examples of the lactam-based pigment include compounds represented by the following formula (A-4).

[ chemical formula 11]

In the formula (A-4), X^A1Represents a double bond, as a geometric isomer, each independently is an E or Z isomer, R^A19Each independently represents a hydrogen atom, a methyl group, a nitro group, a methoxy group, a bromine atom, a chlorine atom, a fluorine atom, a carboxyl group, or a sulfo group, R^A20Each independently represents a hydrogen atom, a methyl group, or a phenyl group, R^A21Each independently represents a hydrogen atom, a methyl group, or a chlorine atom.

The compounds represented by the formula (A-4) may be used alone or in combination of two or more.

Is expressed by the formula (A-4) which is easy to manufactureAspect of the Compound, R^A19Preferably to the 6-position of the indoline ring, R^A21Preferably to the 4-position of the indoline ring. From the same viewpoint, R^A19、R^A20And R^A21Preferably a hydrogen atom.

The compound represented by the formula (a-4) may have EE, ZZ, and EZ isomers as geometric isomers, and may be a single compound of any of these isomers or a mixture of these geometric isomers.

The compound represented by the formula (A-4) can be produced, for example, by the method described in International publication No. 2000/24736 or International publication No. 2010/081624.

In order to disperse the lactam-based pigment in the colorant dispersion liquid well, the average particle diameter of the lactam-based pigment is preferably 10nm or more and 1000nm or less.

In addition, as the pigment, metal particles may also be used.

Such metal particles are preferably particles formed of a metal or particles formed of a metal and a metal compound, and particularly preferably particles formed of a metal.

The metal particles may contain 2 or more kinds of metals or metal compounds in combination.

In particular, the metal particles preferably contain a metal selected from the group consisting of periods 4, 5, and 6 of the long form periodic table (IUPAC 1991) as a main component. The metal particles preferably contain a metal selected from the group consisting of groups 2 to 14 as a main component, and more preferably contain a metal selected from the group consisting of groups 2, 8, 9,10, 11, 12, 13, and 14 as a main component. The metal particles are preferably particles of a metal of group 2, group 10, group 11, group 12 or group 14 of the 4 th, 5 th or 6 th cycle.

Preferable examples of the metal contained in the metal particles include at least 1 selected from the group consisting of copper, silver, gold, platinum, palladium, nickel, tin, cobalt, rhodium, iridium, iron, calcium, ruthenium, osmium, manganese, molybdenum, tungsten, niobium, tantalum, titanium, bismuth, antimony, lead, and alloys thereof. Among these, preferred metals are copper, silver, gold, platinum, palladium, nickel, tin, cobalt, rhodium, calcium, iridium, and alloys thereof, more preferred metals are at least 1 selected from copper, silver, gold, platinum, palladium, tin, calcium, and alloys thereof, and particularly preferred metals are at least 1 selected from copper, silver, gold, platinum, tin, and alloys thereof.

Such metal particles may have a core-shell structure.

Among the above-listed metal particles, an inorganic pigment composed of fine particles mainly composed of a silver-tin (AgSn) alloy (hereinafter, referred to as "AgSn alloy fine particles") is also preferably used as the light-screening agent. The fine AgSn alloy particles may contain an AgSn alloy as a main component, and may contain, for example, Ni, Pd, Au, or the like as another metal component.

The average particle diameter of the AgSn alloy fine particles is preferably 1nm to 300 nm.

When the AgSn alloy is represented by the chemical formula AgxSn, the range of x for obtaining the AgSn alloy with stable chemical properties is more than or equal to 1 and less than or equal to 10, and the range of x for simultaneously obtaining the chemical stability and the blackness is more than or equal to 3 and less than or equal to 4.

Here, in the above-mentioned range of x, the mass ratio of Ag in the AgSn alloy is determined, and as a result,

when x is 1, Ag/AgSn is 0.4762

When x is 3, 3. Ag/Ag3Sn is 0.7317

When x is 4, 4. Ag/Ag4Sn is 0.7843

When x is 10, 10. Ag/Ag10Sn is 0.9008

Therefore, the chemical stability of the AgSn alloy is stable when the Ag content is 47.6-90 mass%, and the chemical stability and blackness can be effectively obtained according to the Ag content when the Ag content is 73.17-78.43 mass%.

The AgSn alloy fine particles can be produced by a general fine particle synthesis method. Examples of the fine particle synthesis method include a gas phase reaction method, a spray pyrolysis method, an atomization method, a liquid phase reaction method, a freeze drying method, a hydrothermal synthesis method, and the like.

Although the insulation property of the AgSn alloy fine particles is high, the surface may be coated with an insulating film in order to further improve the insulation property depending on the use of the coloring composition prepared using the pigment dispersion liquid. As a material of such an insulating film, a metal oxide or an organic polymer compound is preferable.

As the metal oxide, an insulating metal oxide such as silicon oxide (silica), aluminum oxide (alumina), zirconium oxide (zirconia), yttrium oxide (yttria), titanium oxide (titania) or the like can be preferably used.

As the organic polymer compound, resins having insulating properties, such as polyimide, polyether, polyacrylate, polyamine compounds, and the like, can be preferably used.

When the insulating film is formed using a colored composition described later, the film thickness of the insulating film is preferably 1nm to 100nm, more preferably 5nm to 50nm, in order to sufficiently improve the insulation property of the surface of the AgSn alloy fine particles.

The insulating film can be easily formed using a surface modification technique or a surface coating technique. In particular, it is preferable to use an alkoxide such as tetraethoxysilane or triethanolammonium, since an insulating film having a uniform film thickness can be formed at a relatively low temperature.

As the light-shading agent, the perylene pigment, the lactam pigment, and the AgSn alloy fine particles described above may be used alone or in combination.

For the purpose of adjusting the color tone, the light-shading agent may contain not only the above-mentioned black pigment and violet pigment but also pigments having color tones of red, blue, green, yellow, and the like. The color tone of the pigment other than the black pigment and the violet pigment can be selected from known pigments. For example, as a pigment having a color tone other than a black pigment and a violet pigment, the above-mentioned various pigments can be used. The amount of the pigment of a color tone other than the black pigment and the violet pigment is preferably 15% by mass or less, and more preferably 10% by mass or less, based on the total mass of the light-shading agent.

When the inorganic pigment and the organic pigment are used alone or in combination of 2 or more, the organic pigment is preferably used in an amount of 10 parts by mass or more and 80 parts by mass or less, more preferably 20 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of the total amount of the inorganic pigment and the organic pigment.

The pigment described above is mixed with the polyamic acid described later and the dispersion medium containing the aprotic polar organic solvent so that the content of the pigment in the solid component becomes 40 mass% to 99 mass%, thereby forming a pigment dispersion liquid.

The pigment is dispersed in a dispersion medium containing an aprotic polar organic solvent in the presence of a polyamic acid having a specific structure described later, whereby the pigment is stably dispersed in a pigment dispersion liquid for a short time without aggregation of the pigment. The smaller the dispersion particle diameter is, the less the pigment is aggregated and the better the dispersibility is, and for example, the pigment is dispersed so that the dispersion particle diameter becomes 90nm or less.

[ Polyamic acid ]

Polyamic acid is used as a dispersant for dispersing the pigment. It is considered that the molecular chain of the polyamic acid is bonded to the surface of the primary particle of the pigment in the form of a dot by an interaction such as a hydrogen bond or an intermolecular force with the surface of the pigment. Therefore, it is considered that the molecular chain of the polyamic acid acts as a spacer (spacer) on the surface of the primary particle of the pigment, and the dispersion of the pigment is promoted and stabilized. The polyamic acid having a specific structure described later to be mixed in the pigment dispersion liquid is particularly excellent in the dispersion accelerating effect and the dispersion stabilizing effect.

The pigment dispersion liquid preferably does not contain a resin component other than the polyamic acid. When the pigment dispersion liquid contains a resin component other than polyamic acid, the following may be present: since the aggregates of the primary particles of the pigment are coated with the resin, the aggregates are less likely to disintegrate, or adsorption of the molecules of the polyamic acid to the surface of the primary particles of the pigment is inhibited, which makes the pigment less likely to disperse.

The molecular weight of the polyamic acid is preferably 5,000 to 30,000, more preferably 10,000 to 20,000. When the molecular weight of the polyamic acid is within the above range, the pigment can be dispersed well and stably by using the polyamic acid in an amount of a degree that does not largely affect the characteristics of each composition in which the pigment dispersion liquid is blended.

The amount of the polyamic acid used is not particularly limited as long as the content of the pigment in the solid component of the pigment dispersion is 40 mass% or more and 99 mass% or less. In view of ease of dispersion of the pigment, the polyamic acid is preferably used in an amount of 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, based on 100 parts by mass of the pigment.

As the polyamic acid, a polyamic acid including a structural unit represented by the following formula (a1) can be used.

[ chemical formula 12]

A¹Is a group represented by the following formula (a2),

[ chemical formula 13]

Or, A²Is a group represented by the following formula (a3),

-Ar¹-X-Ar²-···(a3)

(in the formula (a3), Ar¹And Ar²Each independently is phenylene or naphthylene which may have a substituent, and X is-CO-NH-. )

In the formula (a1), A¹The carbon number of the tetravalent organic group is preferably 2 to 50, more preferably 2 to 30. A. the¹May be an aliphatic group or an aromatic group, or may be a mixture thereofGroups formed by combining the structures.

In general, A¹The residue obtained by removing 2 acid anhydride groups from tetracarboxylic dianhydride used for producing polyamic acid.

Wherein, in the formula (a1), A²A in the formula (a1) is a group other than the group represented by the formula (a3)¹Is necessarily a group represented by the formula (a 2).

A¹In addition to carbon atoms and hydrogen atoms, halogen atoms, oxygen atoms, and sulfur atoms may be contained. A. the¹When an oxygen atom, a nitrogen atom or a sulfur atom is contained, the oxygen atom, the nitrogen atom or the sulfur atom may be selected from the group consisting of a nitrogen-containing heterocyclic group, -CONH-, -NH-, -N-, -CH-N-, -COO-, -O-, -CO-, -SO-and₂forms of the radicals-S, -S-and-S-are contained in A¹Among them, more preferably selected from-O-, -CO-, -SO-, -SO₂Forms of the radicals-S, -S-and-S-are contained in A¹In (1).

The component A in the formula (a1) is excellent in dispersion stability of the pigment in the pigment dispersion liquid and heat resistance of a colored molded article formed from the colored composition prepared from the pigment dispersion liquid¹The group represented by the formula (a2) is preferable.

As R in the formula (a2)^a11The optional alkyl group is an alkyl group having 1 to 5 carbon atoms. By making as R^a11The carbon number of the alkyl group (b) is in the above range, and a colored molded article having excellent heat resistance can be easily formed using a colored composition containing the pigment dispersion liquid. The number of carbon atoms of the alkyl group is more preferably 1 to 4, and particularly preferably 1 to 3.

R^a11In the case of an alkyl group, the alkyl group may be linear or branched.

As R in formula (a2)^a11From the viewpoint of easy acquisition and purification of the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2), a hydrogen atom, a methyl group, an ethyl group, an n-propyl group or an isopropyl group is more preferable, and a hydrogen atom or a methyl group is particularly preferable.

From providing a tetravalent organic group represented by formula (a2)In terms of ease of purification of tetracarboxylic dianhydride, a plurality of R in the formula (a2)^a11Preferably the same groups.

In the formula (a2), a represents an integer of 0 to 12 inclusive. When the value of a exceeds 12, purification of the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2) is difficult.

From the viewpoint of ease of purification of the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2), the upper limit of a is preferably 5, more preferably 3.

From the viewpoint of chemical stability of the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2), the lower limit of a is preferably 1, more preferably 2.

A in the formula (a2) is particularly preferably 2 or 3.

Can be selected as R in the formula (a2)^a12And R^a13And an alkyl group having 1 to 5 carbon atoms and optionally R^a11The same applies to the alkyl group having 1 to 5 carbon atoms.

R is R from the viewpoint of easiness of purification of tetracarboxylic dianhydride providing a tetravalent organic group represented by the formula (a2)^a12And R^a13A hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is particularly preferable.

Examples of the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2) include norbornane-2-spiro- α -cyclopentanone- α ' -spiro-2 ″ -norbornane-5, 5 ″,6,6 ″ -tetracarboxylic dianhydride (otherwise known as "norbornane-2-spiro-2 ' -cyclopentanone-5 ' -spiro-2 ″ -norbornane-5, 5 ″,6,6 ″ -tetracarboxylic dianhydride"), methylnorbornane-2-spiro- α -cyclopentanone- α ' -spiro-2 ″ - (methylnorbornane) -5,5 ″,6,6 ″ -tetracarboxylic dianhydride, norbornane-2-spiro- α -cyclohexanone- α ' -spiro-2 ″ -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride (distinguished by the name "norbornane-2-spiro-2 ' -cyclohexanone-6 ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride"), methylnorbornane-2-spiro-alpha-cyclohexanone-alpha ' -spiro-2 ' - (methylnorbornane) -5,5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclopropanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclobutanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cycloheptanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclooctanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclononanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclodecanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cycloundecanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclododecanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclotridecanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6,6 ' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclotetradecanone-alpha ' -spiro-2 ' -norbornane-5, 5 ', 6, 6' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha-cyclopentadecanone-alpha '-spiro-2' -norbornane-5, 5 ', 6, 6' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha- (methylcyclopentanone) -alpha '-spiro-2' -norbornane-5, 5 ', 6, 6' -tetracarboxylic dianhydride, norbornane-2-spiro-alpha- (methylcyclohexanone) -alpha '-spiro-2' -norbornane-5, 5 ', 6, 6' -tetracarboxylic dianhydride, and the like.

Further, as the tetracarboxylic dianhydride providing the tetravalent organic group represented by formula (a2), it is preferable that at least 1 of compound (A2-1) represented by formula (a2-1) and compound (A2-2) represented by formula (a2-2) is contained and the total amount of compound (A2-1) and compound (A2-2) is 30 mol% or more, in view of the good thermal properties, mechanical properties, optical properties, and electrical properties of the polyimide resin from which the polyamic acid is purified.

[ chemical formula 14]

(in the formula (a2-1), R^a11、R^a12、R^a13A and R in the formula (a2)^a11、R^a12、R^a13And a have the same meaning. )

[ chemical formula 15]

(in the formula (a2-2), R^a11、R^a12、R^a13A and R in the formula (a2)^a11、R^a12、R^a13And a have the same meaning. ).

The compound (A2-1) represented by the formula (a2-1) is: 2 norbornyl groups are arranged in trans, and the carbonyl group of the cycloalkanone is each an isomer of tetracarboxylic dianhydride (which provides a tetravalent organic group represented by formula (a 2)) having an endo (endo) stereo configuration with respect to the 2 norbornyl groups.

The compound (A2-2) represented by the formula (a2-2) is: 2 norbornyl groups are arranged in cis and the carbonyl group of the cycloalkanone is each an isomer of tetracarboxylic dianhydride (which provides a tetravalent organic group represented by formula (a 2)) having an internal stereoconfiguration with respect to the 2 norbornyl groups.

The method for producing a tetracarboxylic dianhydride containing such an isomer in the above ratio is also not particularly limited, and a known method, for example, the method described in international publication No. 2014/034760, can be suitably used.

As the tetracarboxylic dianhydride providing a1 as a tetravalent organic group, aromatic tetracarboxylic dianhydrides are also preferred.

Examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic dianhydride, 1, 4-bis (3, 4-dicarboxyphenoxy) benzene dianhydride, 3,3 ', 4, 4' -oxydiphthalic dianhydride, 3,3 ', 4, 4' -biphenyltetracarboxylic acid dianhydride, 2,3,3 ', 4' -biphenyltetracarboxylic acid dianhydride, 3,3 ', 4, 4' -benzophenonetetracarboxylic acid dianhydride, and 3,3 ', 4, 4' -diphenylsulfonetetracarboxylic acid dianhydride.

The aromatic tetracarboxylic dianhydride may be, for example, a compound represented by the following general formulae (a2a) to (a2 c).

[ chemical formula 16]

In the above formulae (a2a) and (a2b), R^a1、R^a2And R^a3Each represents a divalent group composed of any one of an aliphatic group which may be substituted with halogen, an oxygen atom, a sulfur atom, an aromatic group with one or more divalent elements interposed therebetween, or a combination thereof. R^a2And R^a3May be the same or different.

Namely, R^a1、R^a2And R^a3May contain a carbon-carbon single bond, a carbon-oxygen-carbon ether bond or a halogen element (fluorine, chlorine, bromine, iodine). Examples of the compound represented by formula (a2a) include 2, 2-bis (3, 4-dicarboxyphenoxy) propane dianhydride, and 1, 4-bis (3, 4-dicarboxyphenoxy) benzene dianhydride.

In the formula (a2c), R is^a4、R^a5Represents a monovalent substituent comprising an aliphatic group which may be substituted with halogen, an aromatic group with one or more divalent elements interposed therebetween, or halogen, or a combination thereof. R^a4And R^a5Each may be the same or different. As the compound represented by formula (a2c), difluoropyromellitic dianhydride, dichloropyromellitic dianhydride, or the like can be used.

Examples of the tetracarboxylic dianhydride containing fluorine in the molecule include (trifluoromethyl) pyromellitic dianhydride, bis (heptafluoropropyl) pyromellitic dianhydride, pentafluoroethyl pyromellitic dianhydride, bis {3, 5-bis (trifluoromethyl) phenoxy } pyromellitic dianhydride, 2-bis (3, 4-dicarboxyphenyl) hexafluoropropane dianhydride, 5,5 '-bis (trifluoromethyl) -3, 3', 4,4 '-tetracarboxybiphenyl dianhydride, 2', 5,5 '-tetrakis (trifluoromethyl) -3, 3', 4,4 '-tetracarboxybiphenyl dianhydride, 5, 5' -bis (trifluoromethyl) -3,3 ', 4, 4' -tetracarboxylic benzophenone dianhydride, bis { (trifluoromethyl) dicarboxyphenoxy } benzene dianhydride, bis { (trifluoromethyl) dicarboxyphenoxy } (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) bis (trifluoromethyl) benzene dianhydride, bis (dicarboxyphenoxy) tetrakis (trifluoromethyl) benzene dianhydride, 2-bis {4- (3, 4-dicarboxyphenoxy) phenyl } hexafluoropropane dianhydride, bis { (trifluoromethyl) dicarboxyphenoxy } biphenyl dianhydride, bis { (trifluoromethyl) dicarboxyphenoxy } bis (trifluoromethyl) biphenyl dianhydride, bis { (trifluoromethyl) dicarboxyphenoxy } diphenyl ether dianhydride, bis (dicarboxyphenoxy) bis (trifluoromethyl) biphenyl dianhydride, difluoropyromellitic dianhydride, 1, 4-bis (3, 4-dicarboxy-trifluorophenoxy) tetrafluorobenzene dianhydride, 1, 4-bis (3, 4-dicarboxy-trifluorophenoxy) octafluorobiphenyl dianhydride, and the like.

In the formula (a1), A²The divalent organic group preferably has 2 to 50 carbon atoms, more preferably 6 to 30 carbon atoms. A. the²The group may be an aliphatic group, an aromatic group, or a combination of these structures.

In general, A²The residue was obtained by removing 2 amino groups from the diamine used for the production of the polyamic acid.

However, in the formula (a1), A¹A in the formula (a1) is a group other than the group represented by the formula (a2)²Is necessarily a group represented by the formula (a 3).

The component A in the formula (a1) is excellent in dispersion stability of the pigment in the pigment dispersion liquid and heat resistance of a colored molded article formed from the colored composition prepared from the pigment dispersion liquid²A group represented by the following formula (a3) is preferred.

-Ar¹-X-Ar²-···(a3)

Ar¹And Ar²Each independently a phenylene group or a naphthylene group which may have a substituent. The substituent is not particularly limited. Preferred examples of the substituent which the phenylene group and the naphthylene group may have include an alkyl group having not less than 1 and not more than 4 carbon atoms, a haloalkyl group having not less than 1 and not more than 4 carbon atoms, an alkoxy group having not less than 1 and not more than 4 carbon atoms, a haloalkoxy group having not less than 1 and not more than 4 carbon atoms, an acyl group having not less than 2 and not more than 4 carbon atoms, and an acyloxy group having not less than 2 and not more than 4 carbon atomsHalogen atoms, and nitrile groups.

As Ar¹And Ar²The number of substituents which the phenylene group or naphthylene group of (1) may have is not particularly limited within a range not interfering with the object of the present invention. The number of the substituents is preferably 0 to 4, more preferably 0 to 2, and further preferably 0 or 1.

As Ar¹And Ar²The phenylene group which may have a substituent(s) of (a) may be any of an o-phenylene group, an m-phenylene group and a p-phenylene group, preferably an m-phenylene group and a p-phenylene group, and more preferably a p-phenylene group.

As Ar¹And Ar²The position of the 2 bonding sites of the naphthylene group which may have a substituent(s) is not particularly limited within the range not interfering with the object of the present invention. As the naphthylene group, naphthalene-1, 4-diyl, naphthalene-1, 3-diyl, naphthalene-1, 2-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl and naphthalene-2, 7-diyl are preferable, and naphthalene-1, 4-diyl, naphthalene-2, 6-diyl and naphthalene-2, 7-diyl are more preferable.

As the group represented by the formula (a3), Ar is preferred¹And Ar²Each independently a group of p-phenylene, m-phenylene, naphthalene-1, 4-diyl, naphthalene-2, 6-diyl, or naphthalene-2, 7-diyl, more preferably Ar¹And Ar²Each independently a p-phenylene group or a m-phenylene group, particularly preferably Ar¹And Ar²Are each a group of p-phenylene.

That is, the unit represented by the formula (a3) is preferably a residue obtained by removing 2 amino groups from 4,4 '-diaminobenzanilide, 3, 4' -diaminobenzanilide, or 4,3 '-diaminobenzanilide, and more preferably a residue obtained by removing 2 amino groups from 4, 4' -diaminobenzanilide.

A²In the case of an organic group containing 1 or more aromatic rings, the organic group may be 1 aromatic group per se, or 2 or more aromatic groups may be bonded to each other via a bond containing an aliphatic hydrocarbon group, a halogenated aliphatic hydrocarbon group, or a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As A²Containing oxygen atom, sulfur atom, and nitrogen atomExamples of the bond of a heteroatom such as-CONH-, -NH-, -N-, -CH N-, -COO-, -O-, -CO-, -SO-and the like₂-, -S-, and-S-S-, etc., preferably-O-, -CO-, -SO-, -SO₂-, -S-, and-S-S-.

A²The aromatic ring bonded to the amino group in (1) is preferably a benzene ring. A. the²When the ring bonded to the amino group in (b) is a condensed ring including 2 or more rings, the ring bonded to the amino group in the condensed ring is preferably a benzene ring.

In addition, A²The aromatic ring contained in (1) may be an aromatic heterocyclic ring.

A²In the case of an organic group containing an aromatic ring, the organic group is preferably at least 1 of the groups represented by the following formulae (21) to (24) from the viewpoint of heat resistance of a colored molded article formed using the colored composition.

[ chemical formula 17]

(in formulas (21) to (24), R¹¹¹Represents 1 kind selected from the group consisting of hydrogen atom, fluorine atom, hydroxyl group, alkyl group having 1 to 4 carbon atoms, and halogenated alkyl group having 1 to 4 carbon atoms. In the formula (24), Q represents a group selected from 9, 9' -fluorenylidene, or the formula: -C₆H₄-、-CONH-C₆H₄-NHCO-、-NHCO-C₆H₄-CONH-、-O-C₆H₄-CO-C₆H₄-O-、-OCO-C₆H₄-COO-、-OCO-C₆H₄-C₆H₄-COO-、-OCO-、-O-、-S-、-CO-、-SO₂-、-C(CF₃)₂-、-C(CH₃)₂-、-CH₂-、-O-C₆H₄-SO₂-C₆H₄-O-、-C(CH₃)₂-C₆H₄-C(CH₃)₂-、-O-C₁₀H₆-O-, and-O-C₆H₄1 member of the group consisting of-O-.

Examples of Q are, -C₆H₄Is phenylene, preferably m-phenylene and p-phenylene, more preferably p-phenylene. In addition, -C₁₀H₆Is naphthalene diyl, preferably naphthalene-1, 2-diyl, naphthalene-1, 4-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl and naphthalene-2, 7-diyl, more preferably naphthalene-1, 4-diyl and naphthalene-2, 6-diyl. )

R in the formulae (21) to (24)¹¹¹From the viewpoint of the heat resistance of the polyamic acid and the heat resistance of the polyimide resin provided from the polyamic acid, a hydrogen atom, a hydroxyl group, a fluorine atom, a methyl group, an ethyl group, or a trifluoromethyl group is more preferable, and a hydrogen atom, a hydroxyl group, or a trifluoromethyl group is particularly preferable.

Q in the formula (24) is preferably 9, 9' -fluorenylidene, -O-C, from the viewpoint of heat resistance of the polyimide resin to be formed₆H₄-O-、-C(CF₃)₂-、-O-、-C(CH₃)₂-, or-CH₂-。

Using an aromatic diamine as A other than the group represented by the formula (a3)²In the case of the diamine compound (b), for example, aromatic diamines shown below can be preferably used.

That is, examples of the aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2, 4-diaminotoluene, 4 ' -diaminobiphenyl, 4 ' -diamino-2, 2 ' -bis (trifluoromethyl) biphenyl, 3 ' -diaminodiphenyl sulfone, 4 ' -diaminodiphenyl sulfide, 4 ' -diaminodiphenylmethane, 4 ' -diaminodiphenyl ether, 3 ' -diaminodiphenyl ether, 4 ' -diaminobenzanilide, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (3-aminophenoxy) benzene, m-phenylenediamine, 2, 4-diaminotoluene, 4 ' -diaminodiphenyl sulfone, 4 ' -diaminodiphenyl sulfide, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (3-aminophenoxy) benzene, m, Bis [4- (4-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) phenyl ] sulfone, 9-bis (4-aminophenyl) fluorene, 9-bis (4-amino-3-methylphenyl) fluorene, and 4, 4' - [1, 4-phenylenebis (1-methylethane-1, 1-diyl) ] diphenylamine, and the like. Among these, p-phenylenediamine, m-phenylenediamine, 2, 4-diaminotoluene, 4 '-diaminodiphenyl ether, and 4, 4' -diaminobenzanilide are preferable from the viewpoint of cost, availability, and the like.

In addition, as A²A chain aliphatic group and/or a silicon atom-containing group having an aromatic ring may be used. As such a silicon atom-containing group, typically, the following groups can be used.

[ chemical formula 18]

In addition, as A²A group represented by the following formula (Si-1) can also be preferably used.

[ chemical formula 19]

(in the formula (Si-1), R¹¹²And R¹¹³Each independently a single bond or methylene group, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, or the like, R¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷Each independently an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an amino group-containing group having 20 carbon atoms, -O-R¹¹⁸A group of (R)¹¹⁸A hydrocarbon group having 1 to 20 carbon atoms), an organic group having 1 to 20 carbon atoms and containing 1 or more epoxy groups, wherein l is an integer of 3 to 50. )

As R in the formula (Si-1)¹¹²And R¹¹³Among them, the alkylene group having 2 to 20 carbon atoms is preferably an alkylene group having 2 to 10 carbon atoms from the viewpoint of heat resistance, and examples thereof include a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.

As R in the formula (Si-1)¹¹²And R¹¹³Medium, carbonThe cycloalkylene group having 3 to 20 carbon atoms is preferably a cycloalkylene group having 3 to 10 carbon atoms from the viewpoint of heat resistance, and examples thereof include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptylene group.

As R in the formula (Si-1)¹¹²And R¹¹³Among them, the arylene group having 6 to 20 carbon atoms is preferably an aromatic group having 6 to 20 carbon atoms from the viewpoint of heat resistance, and examples thereof include a phenylene group and a naphthylene group.

As R in the formula (Si-1)¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷The alkyl group having 1 to 20 carbon atoms in (b) is preferably an alkyl group having 1 to 10 carbon atoms from the viewpoint of heat resistance, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group.

As R in the formula (Si-1)¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷The cycloalkyl group having 3 to 20 carbon atoms in (b) is preferably a cycloalkyl group having 3 to 10 carbon atoms from the viewpoint of heat resistance, and specific examples thereof include a cyclopentyl group, a cyclohexyl group and the like.

As R in the formula (Si-1)¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷The aryl group having 6 to 20 carbon atoms in (b) is preferably an aryl group having 6 to 12 carbon atoms from the viewpoint of heat resistance, and specific examples thereof include a phenyl group, a tolyl group, a naphthyl group and the like.

As R in the formula (Si-1)¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷Examples of the amino group-containing group having not more than 20 carbon atoms in (b) include an amino group, a substituted amino group (e.g., a bis (trialkylsilyl) amino group), and the like.

As R in the formula (Si-1)¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷In (1) -O-R¹¹⁸Examples of the group include methoxy, ethoxy, propoxy, isopropoxy, butoxy, phenoxy, tolyloxy, naphthyloxy, propenyloxy (e.g., allyloxy), and cyclohexyloxy.

Wherein, as R¹¹⁴、R¹¹⁵、R¹¹⁶And R¹¹⁷Methyl, ethyl, propyl, phenyl are preferred.

The group represented by the formula (Si-1) may be introduced in the following manner: a silicon-containing compound having amino groups at both ends is allowed to act on an acid anhydride. Specific examples of such a silicon-containing compound include amino-modified methylphenylsilicone at both ends (for example, X-22-1660B-3 (number average molecular weight: about 4,400) and X-22-9409 (number average molecular weight: about 1,300) manufactured BY shin-Etsu chemical Co., Ltd.), amino-modified dimethylsilicone at both ends (for example, X-22-161A (number average molecular weight: about 1,600), X-22-161B (number average molecular weight: about 3,000) and KF8012 (number average molecular weight: about 4,400) manufactured BY shin-Ether chemical Co., Ltd.), BY16-835U (number average molecular weight: about 900) manufactured BY Toray Dow Corning, and Silaplane FM3311 (number average molecular weight: about 1000) manufactured BY JNC Co., Ltd.), and the like.

The polyamic acid may include a structural unit represented by the following formula (a 4).

[ chemical formula 20]

(in the formula (a4), A³Is a tetravalent organic group other than the group represented by the formula (a2), A⁴Is a divalent organic group other than the group represented by the formula (a 3). )

As A³A tetravalent organic group other than the group represented by formula (a2) described for formula (a1) may be suitably used. As A⁴A divalent organic group other than the group represented by the formula (a3) described for the formula (a1) can be suitably used.

The ratio of the structural unit represented by the formula (a1) in the polyamic acid is preferably 30 mol% or more, more preferably 50 mol% or more, further preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 100 mol% based on the molar amount of the whole structural units.

(method for producing Polyamic acid)

The polyamic acid is generally prepared by reacting a tetracarboxylic dianhydride component with a diamine component.

Typically, a polyamic acid is obtained by reacting a tetracarboxylic dianhydride component and a diamine component in a solvent capable of dissolving both components. The amount of the tetracarboxylic dianhydride component and the diamine component used in the synthesis of the polyamic acid is not particularly limited, but is preferably 0.50 mol or more and 1.50 mol or less, more preferably 0.60 mol or more and 1.30 mol or less, and particularly preferably 0.70 mol or more and 1.20 mol or less, based on 1 mol of the tetracarboxylic dianhydride component.

Examples of the solvent that can be used for the synthesis of the polyamic acid include aprotic polar organic solvents such as N, N' -tetramethylurea, N-methyl-2-pyrrolidone, N-dimethylformamide, N-dimethylacetamide, hexamethylphosphoramide, 1, 3-dimethyl-2-imidazolidinone, and γ -butyrolactone, and glycol ethers such as diethylene glycol dialkyl ether, ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, and propylene glycol monoalkyl ether propionate. These solvents may be used in combination of 2 or more. Among these, N' -tetramethylurea is preferably used.

The amount of the solvent used in the synthesis of the polyamic acid is not particularly limited as long as the polyamic acid having a desired molecular weight can be synthesized. Typically, the amount of the solvent used is preferably 100 parts by mass or more and 4000 parts by mass or less, and more preferably 150 parts by mass or more and 2000 parts by mass or less, relative to 100 parts by mass of the total of the amount of the tetracarboxylic dianhydride component and the amount of the diamine component.

The temperature at which the tetracarboxylic dianhydride component and the diamine component react with each other is not particularly limited as long as the reaction proceeds well. Typically, the reaction temperature of the tetracarboxylic dianhydride component and the diamine component is preferably from-5 ℃ to 150 ℃, more preferably from 0 ℃ to 120 ℃, and particularly preferably from 0 ℃ to 70 ℃. The reaction time of the tetracarboxylic dianhydride component and the diamine component varies depending on the reaction temperature, and is typically preferably 1 hour to 50 hours, more preferably 2 hours to 40 hours, and particularly preferably 5 hours to 30 hours.

[ aprotic polar organic solvent ]

The pigment dispersion liquid contains an aprotic polar organic solvent. By dispersing the pigment in a dispersion medium containing an aprotic polar organic solvent using the polyamic acid described above, the pigment is easily dispersed to a desired degree.

The content of the aprotic polar organic solvent in the dispersion medium is not particularly limited insofar as the dispersed state of the pigment is favorably maintained. Typically, the content of the aprotic polar organic solvent in the dispersion medium is preferably 50% by mass or more, more preferably 70% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

The kind of the aprotic polar organic solvent is not particularly limited within a range not interfering with the object of the present invention. Examples of the preferred aprotic polar organic solvent include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone (NMP), N-dimethylacetamide (DMAc), N-dimethyl isobutyramide, N-diethylacetamide, N-Dimethylformamide (DMF), N-diethylformamide, N-methylcaprolactam, 1, 3-dimethyl-2-imidazolidinone (DMI), pyridine, and N, N' -Tetramethylurea (TMU); lactone-based polar solvents such as β -propiolactone, γ -butyrolactone, γ -valerolactone, δ -valerolactone, γ -caprolactone and e-caprolactone; dimethyl sulfoxide; hexamethylphosphoric triamide; acetonitrile; fatty acid esters such as ethyl lactate and butyl lactate; ketones such as cyclopentanone and cyclohexanone.

The aprotic polar solvent is preferably a nitrogen-containing polar organic solvent represented by the following formula (S1) in view of good solubility of the polyamic acid and easy dispersion of the pigment in a good and stable manner.

[ chemical formula 21]

(in the formula (S1), R^S1And R^S2Each independently of each otherIndependently an alkyl group having 1 to 3 carbon atoms, R^S3Is a group represented by the following formula (S1-1) or the following formula (S1-2).

[ chemical formula 22]

In the formula (S1-1), R^S4Is a hydrogen atom or a hydroxyl group, R^S5And R^S6Each independently an alkyl group having 1 to 3 carbon atoms. In the formula (S1-2), R^S7And R^S8Each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. )

R in the nitrogen-containing polar organic solvent represented by the formula (S1)^S3Specific examples of the group represented by the formula (S1-1) include N, N, 2-trimethylpropanamide, N-ethyl-N, 2-dimethylpropanamide, N-diethyl-2-methylpropanamide, N, 2-trimethyl-2-hydroxypropanamide, N-ethyl-N, 2-dimethyl-2-hydroxypropanamide, and N, N-diethyl-2-hydroxy-2-methylpropanamide.

R in the nitrogen-containing polar organic solvent represented by the formula (S1)^S3Specific examples of the group represented by the formula (S1-2) include N, N, N ', N' -tetramethylurea, N, N, N ', N' -tetraethylurea and the like.

In the nitrogen-containing polar organic solvent represented by the above-described formula (S1), N ' -tetramethylurea and N, N ' -tetraethylurea are preferable, and N, N ' -tetramethylurea is particularly preferable, from the viewpoint of good solubility of polyamic acid and easy dispersion of the pigment in a good and stable manner.

When the dispersion medium contains a dispersion medium other than the aprotic polar organic solvent, such as an aprotic polar organic solvent or an nonpolar solvent, preferable examples of the other solvent include: water; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1, 3-propanediol, isopropylene glycol, polypropylene glycol, pentamethylene glycol, trimethylene glycol, butylene glycol, isobutylene glycol, thiodiethylene glycol, 1, 2-hexanediol, 1, 6-hexanediol, 2-ethyl-1, 3-hexanediol, 1, 2-pentanediol, 1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 7-heptanediol, 1, 8-octanediol, 2-butene-1, 4-diol, and glycerin; and polyhydric alcohol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-t-butyl ether, ethylene glycol monopropyl ether, ethylene glycol mono-isopropyl ether, ethylene glycol monophenyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol mono-t-butyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol monoisopropyl ether.

The amount of the dispersion medium in the pigment dispersion liquid is not particularly limited as long as the dispersion state of the pigment is maintained well. The pigment dispersion liquid contains a dispersion medium in an amount such that the solid content concentration of the pigment dispersion liquid is usually 5 mass% or more and 60 mass% or less, preferably 20 mass% or more and 40 mass% or less.

[ other Components ]

The pigment dispersion liquid may contain various additives conventionally blended in the pigment dispersion liquid. Examples of such additives include viscosity modifiers, surfactants, antioxidants, ultraviolet absorbers, pH modifiers, and antifoaming agents. These additives are used in the same amount as that of the conventional additives to be blended in the pigment dispersion liquid within a range not adversely affecting the properties of the pigment dispersion liquid.

The pigment dispersion liquid described above contains a pigment dispersed well and stably, and provides a colored composition capable of forming a colored molded article having excellent heat resistance. Therefore, the pigment dispersion liquid can be suitably used for coloring various compositions such as a liquid composition like an ink and a colored resin composition. The pigment dispersion liquid described above provides a coloring composition capable of forming a colored molded article excellent in heat resistance, and therefore can be suitably used for coloring a thermosetting composition in particular.

Method for dispersing pigment

The pigment and the polyamic acid are mixed in a dispersion medium containing an aprotic polar organic solvent so that the content of the pigment is 40 to 99 mass%, and then the pigment is dispersed in the dispersion medium.

As a dispersing device used for the dispersion treatment of the pigment, various dispersing devices conventionally used for the dispersion of pigments can be used. Specific examples of suitable dispersing apparatuses include kneaders, salt mill processing kneaders, roll mills, planetary mixers, paint mixers, ball mills, sand mills, attritors, bead mills, annular gap ball mills, homomixers, homogenizers, wet jet mills, high-pressure homogenizers, and ultrasonic homogenizers. When a medium is used as the dispersion device, glass beads, zirconia beads, alumina beads, magnetic beads, styrene beads, or the like can be used as the medium.

When the dispersion treatment is carried out by an ultrasonic homogenizer, it is preferable to use a pigment preliminarily dispersed by the above-mentioned kneader, salt milling treatment kneader, roll mill, planetary mixer, homomixer, homogenizer, wet jet mill, high pressure homogenizer, bead mill, or the like.

When the pigment is dispersed, the pigment, the polyamic acid, and the dispersion medium containing the aprotic polar organic solvent are used in the respective amounts within the above ranges.

By dispersing the pigment by the above-described method, the pigment can be dispersed well and stably in a short time, and a carbon black dispersion liquid that provides a coloring composition that provides a coating film and a molded article having excellent heat resistance can be prepared.

Coloring composition

The coloring composition contains a base component and the pigment dispersion liquid. The content of the pigment in the solid content of the coloring composition is 0.1 mass% or more and less than 50 mass%, preferably 0.1 mass% or more and less than 40 mass%, and more preferably 0.1 mass% or more and less than 30 mass%.

The base component is a component that imparts a coloring composition with an excipient that enables the coloring composition to be molded into a film shape or various three-dimensional shapes. The base component is not particularly limited as long as it is a material capable of imparting a desired excipient property to the coloring composition. As the base component, typically, a resin material formed of a polymer compound, and a reactive low-molecular compound which is crosslinked by heating to generate a polymer compound can be used.

As the base material component contained in the coloring composition, a precursor used for forming a cured product of various thermosetting resins can be used. By heating a coloring composition containing a precursor of a cured product of the thermosetting resin and the pigment dispersion liquid, a colored cured product is formed as a colored molded article. Specific examples of the precursor of the cured product of the thermosetting resin which can be blended in the coloring composition include precursors of thermosetting resins such as epoxy resins, phenol resins, polyimide resins, urea resins, melamine resins, alkyd resins, and urethane resins. The precursor used for forming a cured product is blended with a curing agent, a crosslinking agent, a curing catalyst, and the like, as necessary, in the coloring composition. The curing agent may be a heat-sensitive curing agent or a photosensitive curing agent. When a heat-sensitive curing agent is used, a coating film formed from the coloring composition is heated to form a colored film. In the case of using a photosensitive curing agent, a coating film formed from the coloring composition is exposed to light to form a colored film.

For example, when the cured product is an epoxy resin, an epoxy compound as a base component and a curing agent are blended in the colored composition. When the cured product is a phenol resin, phenols such as phenol and cresol as base components, aldehydes such as formaldehyde as a crosslinking agent, hexamethylenetetramine and the like are blended in the coloring composition. When the cured product is a polyimide resin, a polyamic acid is blended in the colored composition as a base component.

The colored composition preferably contains an epoxy compound or polyamic acid as a base component in view of mechanical properties, solvent resistance, chemical resistance, and the like of the formed colored molded article. Further, from the viewpoint of dispersibility of the pigment in the colored molded article, a colored composition containing a polyamic acid as a base material component is more preferable. The polyamic acid used as the base component may be the same as the polyamic acid blended in the pigment dispersion liquid.

When the base material component contained in the coloring composition is a thermosetting material, the coloring composition is heated to a temperature corresponding to the kind of the base material component, and a colored molded article obtained by heat curing is provided. When the coloring composition is a composition for providing a polyimide resin containing a polyamic acid as a base component, the coloring composition is heated to, for example, 120 ℃ to 350 ℃ inclusive, preferably 150 ℃ to 350 ℃ inclusive.

Examples of the resin material AS the base material component include a polyacetal resin, a polyamide resin, a polycarbonate resin, a polyester resin (e.g., polybutylene terephthalate, polyethylene terephthalate, or polyarylate), an FR-AS resin, an FR-ABS resin, an AS resin, an ABS resin, a polyphenylene ether resin, a polyphenylene sulfide resin, a polysulfone resin, a polyether sulfone resin, a polyether ether ketone resin, a fluorine-based resin, a polyimide resin, a polyamideimide resin, a polyetherimide resin, a polybenzoxazole resin, a polybenzothiazole resin, a polybenzimidazole resin, a silicone resin, a BT resin, polymethylpentene, an ultrahigh molecular weight polyethylene, FR-polypropylene, a (meth) acrylic resin (e.g., polymethyl methacrylate), and polystyrene.

Since the coloring composition described above contains the pigment dispersion liquid, a colored molded article formed using the coloring composition is not easily discolored even when heated to a high temperature, for example, 120 ℃ to 350 ℃. In addition, since the pigment is dispersed in the pigment dispersion liquid well and stably, the colored molded article formed using the above-described coloring composition is colored to a desired concentration.

Examples

[ preparation example 1: production of carbon Black into which acid group has been introduced ]

550g of untreated carbon black (P1, Regal 250R, manufactured by Cabot corporation), 31.5g of sulfanilic acid, and 1000g of ion-exchanged water were charged into a reaction vessel equipped with a jacket and a stirring device, whose jacket temperature was set to 60 ℃. After a solution of 12.6g of sodium nitrite dissolved in 100g of deionized water was charged into a Boron mixer (Braun mixer), the mixture in the mixer was stirred at 60 ℃ for 2 hours at 50 rpm to conduct a diazo coupling reaction. After stirring, the contents of the mixer were cooled to room temperature. Next, the carbon black contained in the contents of the mixer was purified by percolation using deionized water. It was found that benzenesulfonic acids derived from sulfanilic acid were not detected in the washing water, and that benzenesulfonic acid groups were introduced into carbon black by the diazo coupling reaction. The purified carbon black was dried at 75 ℃ overnight and then pulverized to obtain a carbon black having a benzenesulfonic acid group introduced therein (P2).

[ preparation example 2: preparation of carbon Black treated with silane coupling agent ]

50g of untreated carbon black (P1) was mixed with 200g of an isopropanol solution of a silane coupling agent having a concentration of 1.25% by mass, and stirred at 60 ℃ for 3 hours. The stirred suspension containing carbon black was heated to 100 ℃ to volatilize isopropanol and methanol produced as a by-product, thereby obtaining a powder of carbon black (P3) treated with a silane coupling agent. As the silane coupling agent, a silane coupling agent SC-A having the following structure was used.

[ chemical formula 23]

[ examples 1 to 24 and comparative examples 1 to 4]

In examples and comparative examples, the following P1 to P14 were used as pigments.

P1: untreated carbon Black used in preparation example 1

P2: carbon Black having acid group introduced thereinto obtained in production example 1

P3: preparation example 2-treated carbon Black with silane coupling agent

P4: titanium nitride (titanium black)

P5: tungsten (IV) oxide (WO)₂)

P6: copper (II) oxide (CuO)

P7: manganese dioxide (MnO)₂)

P8: iron oxide (Fe)₃O₄)

P9: perylene pigments

P10: lactam pigments

P11: titanium white (titanium oxide (TiO)₂))

P12: cobalt blue (CoAl)₂O₄)

P13: iron oxide red (Fe)₂O₃)

P14: c.i. pigment white 7(ZnS)

In examples and comparative examples, polyamic acids PAA1 to PAA4 each comprising the following structural units and D1(DISPERBYK-167(BYK-Chemie Japan K.K.) each comprising a commercially available dispersant were used as the dispersants. PAA1 and PAA2 belong to polyamic acids having a structural unit represented by the formula (a 1). PAA3 and PAA4 belong to polyamic acids that do not have the structural unit represented by the formula (a 1).

The mass average molecular weight of PAA1 was 12000 in terms of polystyrene. The mass average molecular weight of PAA2 was 11000 in terms of polystyrene. The mass average molecular weight of PAA3 was 12000 in terms of polystyrene. The mass average molecular weight of PAA4 was 11000 in terms of polystyrene.

[ chemical formula 24]

In examples and comparative examples, N' -Tetramethylurea (TMU) or N-methyl-2-pyrrolidone (NMP) was used as an aprotic polar organic solvent.

In examples 1 to 16 and comparative examples 1 to 4, 15g of the pigment of the type shown in Table 1, 7.5g of the dispersant of the type shown in Table 1, and 50g of the dispersion medium of the type shown in Table 1 were mixed to obtain a mixed solution having a pigment content of 67 mass% in the solid content. In comparative example 4, no dispersant was used. Next, the obtained mixed solution was stirred to disperse the pigment. The obtained high-concentration pigment dispersion was diluted to a solid content concentration of 30 mass% using the dispersion medium of the type described in table 1 to obtain a pigment dispersion.

In examples 17 to 20, a pigment dispersion was obtained in the same manner as described above except that the pigment content in the solid content was changed to 80%.

In examples 21 to 24, pigment dispersions were obtained in the same manner as described above except that the pigment content in the solid content was 50%.

Using the obtained pigment dispersion liquid, the dispersion stability of the pigment was evaluated in the following manner. The evaluation results of dispersibility are shown in table 1.

< evaluation of Dispersion stability >

After the pigment dispersion liquid was prepared, the pigment dispersion liquid was allowed to stand at room temperature for 1 week. The case where no sedimentation of the pigment was observed after 1 week of standing was judged as "O", and the case where the sedimentation was confirmed was judged as "X".

[ Table 1]

Examples 1 to 24 show that when a pigment is dispersed in an aprotic polar organic solvent using a polyamic acid containing a structural unit represented by the formula (a1), a pigment dispersion liquid having good dispersion stability can be prepared regardless of the type of the pigment.

As is clear from comparative examples 1,2, and 4, even when the pigment is dispersed in the aprotic polar organic solvent using the polyamic acid as the dispersant, it is difficult to prepare a pigment dispersion liquid having good dispersion stability when the polyamic acid does not contain the structural unit represented by the formula (a 1).

[ examples 25 to 42 and comparative examples 5 to 8]

A coloring composition was obtained by uniformly mixing 10g of the carbon black dispersion obtained in the examples or comparative examples described in the column of the type of dispersion in Table 2, 9g of the polyamic acid of the type described in Table 2, and 100g of the solvent of the type described in Table 2.

The heat resistance of the cured product of the obtained colored composition was evaluated by the following method. The evaluation results are set forth in table 2.

< evaluation of Heat resistance >

The coloring composition was applied onto the wafer substrate by using a spin coater (manufactured by Mikasa, 1H-360S). The coating film on the wafer substrate was heated at 300 ℃ for 1 hour to form a cured film having a thickness of about 1.0. mu.m. From the cured film formed by heating to 300 ℃, 5. mu.g of each sample for heat resistance evaluation was cut. The samples for heat resistance evaluation were measured by a differential thermal/thermogravimetric apparatus (TG/DTA-6200, manufactured by Seiko Instruments Inc.) in an air stream at a temperature increase rate of 10 ℃ per minute to obtain a TG curve. The 5% weight loss temperature of the sample was determined from the obtained TG curve. The good is judged when the 5% weight loss temperature is more than 400 ℃, and the good is judged when the 5% weight loss temperature is not more than 400 ℃.

[ Table 2]

It is seen from examples 25 to 42 that a colored composition obtained by adding a polyamic acid as a base material component to a pigment dispersion liquid obtained by dispersing a pigment in an aprotic polar organic solvent using a polyamic acid containing a structural unit represented by the formula (a1) provides a cured product having excellent heat resistance.

On the other hand, as is clear from comparative examples 3 and 7, when a commercially available dispersant (which is not a polyamic acid) is used as the dispersant, even if the pigment can be stably dispersed, it is difficult to prepare a pigment dispersion liquid that can provide a coloring composition that provides a cured product having excellent heat resistance.

Claims

1. A pigment dispersion liquid containing a pigment, a polyamic acid, and an aprotic polar organic solvent,

the content of the pigment in the solid content is 40-99% by mass,

in the formula (a1), A¹Is a tetravalent organic radical, A²Is a divalent organic group, and is a divalent organic group,

wherein, A is¹Is a group represented by the following formula (a2),

in the formula (a2), R^a11、R^a12And R^a13Each independently represents 1 selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a fluorine atom, and a is an integer of 0 to 12 inclusive;

or, the A is²Is a group represented by the following formula (a3),

-Ar¹-X-Ar²-···(a3)

in the formula (a3), Ar¹And Ar²Each independently is phenyl or naphthyl which may have a substituent, and X is-CO-NH-.

2. The pigment dispersion liquid according to claim 1, wherein the ratio of the structural unit represented by the formula (a1) in the polyamic acid to the total structural units of the polyamic acid is 30 mol% or more.

3. The pigment dispersion liquid according to claim 1 or 2, wherein the aprotic polar organic solvent is a nitrogen-containing polar organic solvent represented by the following formula (S1),

in the formula (S1), R^S1And R^S2Each independently an alkyl group having 1 to 3 carbon atoms, R^S3Is a hydrogen atom or a group represented by the following formula (S1-1) or the following formula (S1-2),

R^S4is a hydrogen atom or a hydroxyl group, R^S5And R^S6Each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, R^S7And R^S8Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R^S3In the case of a group represented by the formula (S1-1), R^S2And R^S3May be bonded to each other to form a ring.

4. The pigment dispersion liquid according to claim 3, wherein the nitrogen-containing polar organic solvent is N, N, N ', N' -tetramethylurea.

5. A coloring composition comprising a base component and the pigment dispersion liquid according to any one of claims 1 to 4,

the pigment content in the solid component is 0.1 mass% or more and less than 50 mass%.

6. A method of dispersing a pigment comprising the steps of:

mixing a pigment and a polyamic acid in a dispersion medium containing an aprotic polar organic solvent so that the content of the pigment in the solid content is 40 to 99 mass%, and then dispersing the pigment in the aprotic polar organic solvent,

wherein, A is¹Is a group represented by the following formula (a2),

in the formula (a2), R^a11、R^a12And R^a13Each independently represents 1 selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and a fluorine atom, a is an integer of 0 to 12 inclusive,

or, the A is²Is a group represented by the following formula (a3),

-Ar¹-X-Ar²-···(a3)

in the formula (a3), Ar¹And Ar²Each independently is phenylene or naphthylene which may have a substituent, and X is-CO-NH-.