JP7639302B2 - Infrared absorbing composition and optical filter - Google Patents

Description

The present invention relates to an infrared absorbing composition containing a squarylium compound.

The main applications of infrared absorbing compositions include infrared absorbing films and plates that block heat rays for energy conservation, agricultural infrared absorbing films for selective use of sunlight, recording media that use the heat absorbed by infrared rays, infrared cut filters for electronic devices, infrared filters for photography, protective glasses, sunglasses, heat ray blocking films, dyes for optical recording, optical character reading and recording, anti-copying of confidential documents, electrophotographic photoreceptors, laser fusion, and sensors for biometric authentication (fingerprint authentication and vein authentication).

Typical infrared absorbing dyes used in infrared absorbing compositions include squarylium compounds, phthalocyanine compounds, cyanine compounds, and diimonium compounds. Phthalocyanine compounds include phthalocyanine compounds or naphthalocyanine compounds having a substituent, phthalocyanine compounds having an amino group, phthalocyanine compounds having an aryloxy group, and fluorine-containing phthalocyanine compounds.

Patent Document 1 discloses an infrared absorbing composition.

JP 2016-164670 A

However, conventional infrared absorbing compositions have problems with significant reduction in the thickness of the coating after development (residual film after development) when forming patterns using photolithography, and with insufficient heat resistance of the coating.

The present invention aims to provide an infrared absorbing composition that can suppress the reduction in the thickness of a coating film (residual film after development) after development in a photolithography method and suppress the deterioration of the heat resistance of the coating film.

The infrared absorbing composition of the present invention comprises a squarylium compound (A), a binder resin (B), a polymerizable compound (C) and a photopolymerization initiator (D),
The binder resin (B) includes a binder resin (B1) having a monomer unit (b1) having one or more skeletons selected from a tricyclodecane skeleton and a dicyclopentadiene skeleton in one molecule, and a carboxyl group-containing monomer unit (b2), and having no polymerizable unsaturated group.

The present invention described above can provide an infrared absorbing composition and an optical filter that can suppress the reduction in the thickness of the coating film (residual film after development) after development in a photolithography method and suppress the deterioration of the heat resistance of the coating film.

The terms used in this specification are defined below. Unless otherwise specified, the terms "(meth)acryloyl", "(meth)acrylic", "(meth)acrylic acid", "(meth)acrylate", or "(meth)acrylamide" refer to "acryloyl and/or methacryloyl", "acrylic and/or methacrylic", "acrylic acid and/or methacrylic acid", "acrylate and/or methacrylate", or "acrylamide and/or methacrylamide", respectively. "C.I." stands for Color Index (C.I.). The monomer is a compound containing a polymerizable unsaturated group. The polymerizable unsaturated group is a vinyl group, a (meth)acryloyl group, an allyl group, or the like. The glass transition temperature is a theoretical value.

The infrared absorbing composition of the present invention comprises a squarylium compound (A), a binder resin (B), a polymerizable compound (C) and a photopolymerization initiator (D),
The binder resin (B) contains a binder resin (B1) having a monomer unit (b1) having one or more skeletons selected from a tricyclodecane skeleton and a dicyclopentadiene skeleton in one molecule, and a carboxyl group-containing monomer unit (b2), and having no polymerizable unsaturated group. The infrared absorbing composition of the present invention contains a binder resin (B1) that is not photocurable, and as a result, due to the action of the monomer unit (b1) having one or more skeletons selected from a bulky tricyclodecane skeleton and a dicyclopentadiene skeleton, a reduction in the thickness of the coating film after development by a photolithography method can be suppressed, and a decrease in the heat resistance of the coating film over time can be suppressed.

<Squarylium Compound (A)>
The squarylium compound (A) is a compound having a maximum absorption wavelength between 700 and 900 nm in the range of 400 to 1000 nm. With a maximum absorption wavelength of 700 to 900 nm, for example, when used in an infrared sensor, light in the near infrared region that is detected as noise can be widely cut, even to the long wavelength side. The value of the maximum absorption wavelength of the squarylium compound (A) is a value measured by the method described in the Examples below.

When the absorbance of the squarylium compound (A) at the maximum absorption wavelength in the range of 400 to 1000 nm is (I1) and the absorbance at 650 nm is (I2), it is preferable that (I2)/(I1) is 0.5 or less.

The squarylium compound (A) is preferably at least one of the compounds represented by the following general formula (1) and general formula (2). Generally, squarylium compounds included in cyanine compounds have low heat resistance, but the compounds represented by general formula (1) and general formula (2) have high heat resistance.

General formula (1)

(X ₁ to X ₁₀ each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, an aralkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an amino group, a substituted amino group, a sulfo group, -SO ₂ NR ₁ R ₂ , -COOR ₁ , -CONR ₁ R ₂ , a nitro group, a cyano group, or a halogen atom. R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group which may have a substituent. X ₁ to X ₁₀ may be bonded to each other to form a ring.)

Examples of the "alkyl group which may have a substituent" in X ₁ to X ₁₀ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a tert-butyl group, a tert-amyl group, a 2-ethylhexyl group, a stearyl group, a chloromethyl group, a trichloromethyl group, a trifluoromethyl group, a 2-methoxyethyl group, a 2-chloroethyl group, a 2-nitroethyl group, a cyclopentyl group, a cyclohexyl group, a dimethylcyclohexyl group, etc. Among these, the methyl group, the ethyl group, and the n-propyl group are preferred from the viewpoints of imparting durability and ease of synthesis, and the methyl group is particularly preferred.

Examples of the "alkenyl group which may have a substituent" in X ₁ to X ₁₀ include a vinyl group, a 1-propenyl group, an allyl group, a 2-butenyl group, a 3-butenyl group, an isopropenyl group, an isobutenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-pentenyl group, a 1-hexenyl group, a 2-hexenyl group, a 3-hexenyl group, a 4-hexenyl group, a 5-hexenyl group, etc. Among these, a vinyl group and an allyl group are preferred from the viewpoints of imparting durability and ease of synthesis.

Examples of the "aryl group which may have a substituent" in X ₁ to X ₁₀ include a phenyl group, a naphthyl group, a 4-methylphenyl group, a 3,5-dimethylphenyl group, a pentafluorophenyl group, a 4-bromophenyl group, a 2-methoxyphenyl group, a 4-diethylaminophenyl group, a 3-nitrophenyl group, a 4-cyanophenyl group, etc. Among these, the phenyl group and the 4-methylphenyl group are preferred from the viewpoints of imparting durability and ease of synthesis.

In X ₁ to X ₁₀ , the "aralkyl group which may have a substituent" is, for example, a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group, etc. Among these, a benzyl group is preferred from the viewpoints of imparting durability and ease of synthesis.

In X ₁ to X ₁₀ , examples of the "alkoxy group even if it has a substituent" include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an n-octyloxy group, a 2-ethylhexyloxy group, a trifluoromethoxy group, a cyclohexyloxy group, a stearyloxy group, etc. Among these, a methoxy group, an ethoxy group, and a trifluoromethoxy group are preferred from the viewpoints of imparting durability and ease of synthesis.

Examples of the "aryloxy group which may have a substituent" in X ₁ to X ₁₀ include a phenoxy group, a naphthyloxy group, a 4-methylphenyloxy group, a 3,5-chlorophenyloxy group, a 4-chloro-2-methylphenyloxy group, a 4-tert-butylphenyloxy group, a 4-methoxyphenyloxy group, a 4-diethylaminophenyloxy group, a 4-nitrophenyloxy group, etc. Among these, the phenoxy group and the naphthyloxy group are preferred from the viewpoints of imparting durability and ease of synthesis.

Examples of the "substituted amino group" in X ₁ to X ₁₀ include a methylamino group, an ethylamino group, an isopropylamino group, an n-butylamino group, a cyclohexylamino group, a stearylamino group, a dimethylamino group, a diethylamino group, a dibutylamino group, an N,N-di(2-hydroxyethyl)amino group, a phenylamino group, a naphthylamino group, a 4-tert-butylphenylamino group, a diphenylamino group, an N-phenyl-N-ethylamino group, etc. Among these, the dimethylamino group and the diethylamino group are preferred from the viewpoints of imparting durability and ease of synthesis.

In X ₁ to X ₁₀ , the "halogen atom" includes, for example, fluorine, bromine, chlorine and iodine.

X ₁ to X ₁₀ may be bonded to each other to form a ring. Examples of the structure are shown below.

The "alkyl group which may have a substituent" in R ₁ and R ₂ is, for example, the same as X ₁ to X ₁₀ .

X ₁ to X ₁₀ preferably contain an unsubstituted alkyl group, more preferably at least one of X ₃ , X ₄ , X ₇ and X ₈ is an unsubstituted alkyl group, and particularly preferably X ₃ and X ₇ are unsubstituted alkyl groups. The unsubstituted alkyl group is preferably a methyl group.

(Method for producing compounds represented by general formulas (1) and (2))
The compound represented by the general formula (1) can be produced, for example, by the method described in JP-A-2019-211764. The compound represented by the general formula (2) can be produced, for example, by the method described in JP-A-2019-1983.

The squarylium compound (A) can be used alone or in combination of two or more types.

The content of the squarylium compound (A) in the non-volatile matter of the infrared absorbing composition is preferably 0.01 to 50 mass %, more preferably 0.1 to 30 mass %. By including an appropriate amount, appropriate infrared absorption can be obtained.

In this specification, the squarylium compound (A) is preferably used by dispersing it into fine particles using a dispersant. Dispersing it into fine particles makes it easier for the squarylium compound (A) to exhibit its performance, and also improves the durability of the compound itself. The dispersant is preferably a resin-type dispersant.

The average primary particle diameter of the squarylium compound (A) after dispersion is preferably 1 to 500 nm, more preferably 10 to 200 nm, and even more preferably 10 to 100 nm. By setting the average primary particle diameter to an appropriate value, the squarylium compound (A) is less likely to aggregate, and the absorption spectrum becomes sharper. The average primary particle diameter can be measured by directly measuring the size of about 100 primary particles from an electron microscope photograph using a transmission electron microscope (TEM). Specifically, the minor axis diameter and major axis diameter of each primary particle are measured, and the average value is taken as the primary particle diameter of the particle. The volume (mass) of each particle is calculated by approximating the cube of the calculated particle diameter, and the volume average particle diameter is taken as the average primary particle diameter.

<Basic Resin-Type Dispersant (E)>
The resin type dispersant used in the infrared absorbing composition is preferably a basic resin type dispersant (E). The basic resin type dispersant (E) is, for example, a resin containing a basic group such as a tertiary amino group, a quaternary ammonium base, or a nitrogen-containing heterocycle. The basic group is preferably an amino group or a quaternary ammonium base, and more preferably contains both. The basic resin type dispersant (E) preferably has an amine value of 50 to 100 mgKOH/g. In terms of resins, the basic resin type dispersant (E) may, for example, be a nitrogen atom-containing graft copolymer, a nitrogen atom-containing acrylic block copolymer, or a urethane-based polymer dispersant.

A preferred embodiment of the basic resin type dispersant (E) is a block copolymer consisting of an A block having a tertiary amino group and a quaternary ammonium salt group, and a B block which is a monomer polymer having an alkyl (meth)acrylate as a main component. The A block functions as an adsorption site for the infrared absorbing dye (A), whereas the B block functions as a steric repulsion site. The basic resin type dispersant (E) has an A block and a B block, and thus greatly improves the dispersion stability of the squarylium compound (A). Specifically, the basic resin type dispersant described in JP 2019-211764 A can be preferably used.

In addition to the basic resin-type dispersant (E), an acidic resin-type dispersant can be used in combination.

Examples of acidic resin-type dispersants include resin-type dispersants having an aromatic carboxylic acid structure. These dispersants can be synthesized by methods described in WO2008/007776, JP2008-029901A, JP2009-155406A, JP2010-185934A, JP2011-157416A, JP2009-251481A, JP2007-23195A, JP1996-143651A, etc.

The content of the resin-type dispersant is preferably 3 to 200 mass% and more preferably 5 to 100 mass% relative to 100 parts by mass of the squarylium compound (A). When an appropriate amount is contained, the dispersion stability is improved.

Resin-type dispersants can be used alone or in combination of two or more types.

<Binder Resin (B)>
The binder resin (B) is a resin having a transmittance of 80% or more in the entire wavelength range of 400 to 700 nm when a coating having a thickness of 2 μm is formed. The transmittance is preferably 95% or more. In terms of curability, the binder resin (B) may be, for example, a thermoplastic resin or an active energy ray curable resin. In terms of physical properties, the binder resin is preferably an alkali-soluble resin from the viewpoint of developability. The alkali solubility is for imparting development solubility in the alkali development step of the photolithography method, and an acidic group is required. In addition, the active energy ray curable resin may have a thermosetting group (for example, an epoxy group, an oxetane group, etc.).

<Thermoplastic resin>
Examples of thermoplastic resins include acrylic resins, butyral resins, styrene-maleic acid copolymers, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinyl acetate, polyurethane resins, polyester resins, vinyl resins, alkyd resins, polystyrene resins, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene (HDPE, LDPE), polybutadiene, and polyimide resins.
Examples of the alkali-soluble thermoplastic resin (hereinafter referred to as alkali-soluble resin) include resins having an acidic group such as a carboxyl group or a sulfonic group. Examples of the alkali-soluble resin include acrylic resins having an acidic group, α-olefin/maleic acid (anhydride) copolymers, styrene/styrene sulfonic acid copolymers, ethylene/(meth)acrylic acid copolymers, and isobutylene/maleic acid (anhydride) copolymers. Among these, acrylic resins having an acidic group and styrene/styrene sulfonic acid copolymers are preferred in terms of improving developability, heat resistance, and transparency.

<Active energy ray curable resin>
The active energy ray-curable resin is preferably a resin synthesized by, for example, the following method (i) or (ii), which further improves the crosslink density of the coating film formed from the infrared absorbing composition by light irradiation.

[Method (i)]
In the method (i), for example, a polymer of an epoxy group-containing monomer and other monomers is first synthesized, and then a carboxyl group-containing monomer is added to the epoxy group of the polymer, and the resulting hydroxyl group is reacted with a polybasic acid anhydride to obtain an alkali-soluble resin (C2).

Examples of epoxy group-containing monomers include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 2-glycidoxyethyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 3,4-epoxycyclohexyl (meth)acrylate. Among these, glycidyl (meth)acrylate is preferred from the viewpoint of reactivity.

Examples of monocarboxyl group-containing monomers include monocarboxylic acids such as (meth)acrylic acid, crotonic acid, o-, m-, and p-vinylbenzoic acid, and (meth)acrylic acid substituted with haloalkyl, alkoxyl, halogen, nitro, or cyano at the α-position.

Examples of polybasic acid anhydrides include tetrahydrophthalic anhydride, phthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, etc.

The monomers and polybasic acid anhydrides can be used alone or in combination of two or more types.

In addition, as a method similar to method (i), for example, a carboxyl group-containing monomer and other monomers are synthesized to produce a polymer. Then, an epoxy group-containing monomer is added to some of the carboxyl groups of the polymer to obtain an alkali-soluble resin (C2).

[Method (ii)]
In the method (ii), for example, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and other monomers are synthesized to prepare a polymer, and then the hydroxyl group of the polymer is reacted with an isocyanate group of an isocyanate group-containing monomer.

Examples of the hydroxyl group-containing monomer include hydroxyalkyl methacrylates such as 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 2-, 3- or 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, and cyclohexanedimethanol mono(meth)acrylate. Other examples include polyether mono(meth)acrylates obtained by addition polymerization of ethylene oxide, propylene oxide, and/or butylene oxide to hydroxyalkyl (meth)acrylates, and polyester mono(meth)acrylates obtained by addition of poly(γ-valerolactone), poly(ε-caprolactone, and/or poly(12-hydroxystearic acid). Among these, 2-hydroxyethyl methacrylate and glycerol mono(meth)acrylate are preferred, and glycerol mono(meth)acrylate is more preferred.

Examples of isocyanate group-containing monomers include 2-(meth)acryloylethyl isocyanate, 2-(meth)acryloyloxyethyl isocyanate, and 1,1-bis[methacryloyloxy]ethyl isocyanate.

Monomers that can be used other than the above monomers include the other monomers exemplified in method (i) above, as well as phosphate ester group-containing monomers, etc.

A phosphate ester group-containing monomer is, for example, a compound obtained by reacting the hydroxyl group of a hydroxyl group-containing monomer with a phosphate esterifying agent such as phosphorus pentoxide or polyphosphoric acid.

The acid value of the binder resin (B) is preferably 50 to 200 mgKOH/g, more preferably 70 to 180 mgKOH/g, and even more preferably 90 to 170 mgKOH/g. A moderate acid value allows for a high level of balance between alkali solubility, adhesion, and residue suppression.

The weight average molecular weight (Mw) of the binder resin (B) in the present invention is preferably 2,000 to 40,000, more preferably 3,000 to 30,000, and even more preferably 4,000 to 20,000. The value of Mw/Mn is preferably 10 or less. Here, Mn is the number average molecular weight. A suitable weight average molecular weight allows for a high degree of both adhesion to the substrate and developability.

Each raw material used in the synthesis of binder resin (B) can be used alone or in combination of two or more types.

The binder resin (B) can be used alone or in combination of two or more types.

The content of the binder resin (B) is preferably 20 to 400 parts by mass, and more preferably 50 to 250 parts by mass, per 100 parts by mass of the squarylium compound (A). When an appropriate amount is contained, a coating can be easily formed and good color characteristics can be easily obtained.

(Binder Resin (B1))
In the present invention, the binder resin (B) contains a monomer unit (b1) having one or more of a tricyclodecane skeleton and a dicyclopentadiene skeleton in one molecule, and a carboxyl group-containing monomer unit (b2), and contains a binder resin (B1) having no polymerizable unsaturated group. The synergistic effect of the monomer unit (b1) and the absence of a polymerizable unsaturated group can suppress the reduction in the thickness of the coating after development and the deterioration of heat resistance over time.

The glass transition temperature of the binder resin (B1) of the present invention is preferably 70 to 120° C., more preferably 80 to 100° C., as calculated by the Fox formula of the following formula (2).
Formula (2) Fox formula 1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ + . . . +W _n /Tg _n
(Wherein, _W1 to _Wn indicate the weight fractions of n types of monomers used, and _Tg1 to _Tgn indicate the glass transition temperatures (units are absolute temperature "K") of homopolymers (homopolymers of monomers).

(Monomer unit (b1))
Examples of the monomer forming the monomer unit (b1) include dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Among these, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentanyloxyethyl (meth)acrylate are preferred.

(Carboxyl Group-Containing Monomer Unit (b2))
The carboxyl group-containing monomer forming the carboxyl group-containing monomer unit (b2) may be a carboxylic acid selected from other unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, etc., used alone or in combination, or a monomer containing a hydroxy group and a carboxyl group in the same molecule such as α-(hydroxymethyl)acrylic acid. Of these, acrylic acid and methacrylic acid are preferred.

The binder resin (B1) can contain other monomer units (b3) in addition to the monomer units (b1) and the carboxyl group-containing monomer units (b2).

Examples of the monomer forming the other monomer unit (b3) include (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and ethoxypolyethylene glycol (meth)acrylate;
Examples of (meth)acrylamides include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, diacetone(meth)acrylamide, and acryloylmorpholine; styrenes such as styrene and α-methylstyrene; vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether; and fatty acid vinyls such as vinyl acetate and vinyl propionate.

Cyclohexylmaleimide, phenylmaleimide, methylmaleimide, ethylmaleimide, 1,2-bismaleimideethane 1,6-bismaleimidehexane, 3-maleimidopropionic acid, 6,7-methylenedioxy-4-methyl-3-maleimidocoumarin, 4,4'-bismaleimidediphenylmethane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, N,N'-1,3-phenylenedimaleimide, N,N'-1,4-phenylenedimaleimide, N-(1-pyrenyl)maleimide, N-(2,4,6-trichlorophenyl)maleimide, N-(4-aminophenyl)maleimide, N-(4-nitrophenyl)maleimide, N-benzylmaleimide, N-bromomethyl-2,3-dichloromaleimide, N-succinimidyl-3-maleimide N-substituted maleimides such as N-benzoate, N-succinimidyl-3-maleimidopropionate, N-succinimidyl-4-maleimidobutyrate, N-succinimidyl-6-maleimidohexanoate, N-[4-(2-benzimidazolyl)phenyl]maleimide, and 9-maleimidoacridine, EO-modified cresol acrylate, n-nonylphenoxy polyethylene glycol acrylate, phenoxyethyl acrylate, ethoxylated phenyl acrylate, ethylene oxide (EO)-modified (meth)acrylate of phenol, EO- or propylene oxide (PO)-modified (meth)acrylate of paracumylphenol, EO-modified (meth)acrylate of nonylphenol, and PO-modified (meth)acrylate of nonylphenol.

The content of the monomer unit (b1) is preferably 1 to 40 mass %, more preferably 5 to 30 mass %, of the total monomer units of the binder resin (B1). When contained in an appropriate amount, it suppresses the reduction in the thickness of the coating after development in the photolithography method, and improves heat resistance and chemical resistance.

The content of the carboxyl group-containing monomer unit (b2) is preferably 5 to 50 mass % of the total monomer units of the binder resin (B1), and more preferably 10 to 40 mass %. When an appropriate amount is contained, the developability is improved.

(Resins other than binder resin (B1))
The binder resin (B) may be used in combination with other resins other than the binder resin (B1). The other resins are preferably thermoplastic resins, which makes it easier to adjust the degree of hardening of the coating.

<Polymerizable compound (C)>
The polymerizable compound (C) is a monomer or oligomer containing a polymerizable unsaturated group. Examples of the polymerizable compound (C) include an acid group-containing monomer, a urethane bond-containing monomer, and other monomers.

Examples of the acid group of the acid group-containing monomer include a sulfonic acid group, a carboxyl group, and a phosphoric acid group.

Examples of acid group-containing monomers include esters of free hydroxyl group-containing poly(meth)acrylates of polyhydric alcohols and (meth)acrylic acid with dicarboxylic acids; esters of polycarboxylic acids with monohydroxyalkyl (meth)acrylates, etc. Specific examples include free carboxyl group-containing monoesters of monohydroxy oligoacrylates or monohydroxy oligomethacrylates, such as trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol pentamethacrylate, with dicarboxylic acids, such as malonic acid, succinic acid, glutaric acid, and phthalic acid; and free carboxyl group-containing oligoesters of tricarboxylic acids, such as propane-1,2,3-tricarboxylic acid (tricarballylic acid), butane-1,2,4-tricarboxylic acid, benzene-1,2,3-tricarboxylic acid, benzene-1,3,4-tricarboxylic acid, and benzene-1,3,5-tricarboxylic acid, with monohydroxy monoacrylates or monohydroxy monomethacrylates, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate.

(Urethane bond-containing monomer)
Examples of the urethane bond-containing monomer include polyfunctional urethane acrylates obtained by reacting a (meth)acrylate having a hydroxyl group with a polyfunctional isocyanate, and polyfunctional urethane acrylates obtained by reacting an alcohol with a polyfunctional isocyanate and further reacting the alcohol with a (meth)acrylate having a hydroxyl group.

Examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol ethylene oxide modified penta(meth)acrylate, dipentaerythritol propylene oxide modified penta(meth)acrylate, dipentaerythritol caprolactone modified penta(meth)acrylate, glycerol acrylate methacrylate, glycerol dimethacrylate, 2-hydroxy-3-acryloylpropyl methacrylate, reaction product of an epoxy group-containing compound and carboxy(meth)acrylate, and hydroxyl group-containing polyol polyacrylate.

Examples of polyfunctional isocyanates include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, isophorone diisocyanate, polyisocyanate, etc.

Other monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, β-carboxyethyl (meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, phenoxyhexaethylene glycol (meth)acrylate, trimethylolpropane PO modified tri(meth)acrylate, trimethylolpropane EO modified tri(meth)acrylate, isocyanuric acid EO modified di(meth)acrylate, isocyanuric acid EO modified tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, Examples of the acrylic acid esters and methacrylic acid esters include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 1,6-hexanediol diglycidyl ether di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol diglycidyl ether di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tricyclodecanyl(meth)acrylate, methylolated melamine (meth)acrylic acid ester, epoxy (meth)acrylate, and urethane acrylate, as well as (meth)acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-vinylformamide, and acrylonitrile.

In this specification, the photopolymerizable compound (C) preferably contains a compound having three polymerizable unsaturated groups. This improves the photocurability and further improves the heat resistance.

The polymerizable compound (C) may be used alone or in combination of two or more types.

The content of the polymerizable compound (C) is preferably 1 to 50 mass %, and more preferably 2 to 40 mass parts, based on 100 mass % of the nonvolatile content of the infrared absorbing composition. When an appropriate amount is added, the curability and developability are further improved.

<Photopolymerization initiator (D)>
Examples of the photopolymerization initiator (D) include acetophenone-based compounds such as 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-2-(phenylmethyl)-1-butanone, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone; benzoin, benzoin methyl ether, benzo benzoin compounds such as benzoin ethyl ether, benzoin isopropyl ether, or benzil dimethyl ketal; benzophenone compounds such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, or 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, or 2,4-diethylthioxanthone; 2,4,6-trichloro-s-triazine , 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxy-naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, or 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine. Examples of the compounds include triazine-based compounds such as azine, oxime ester-based compounds such as 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyloxime)], or ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, or 1-(O-acetyloxime), phosphine-based compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide or diphenyl-2,4,6-trimethylbenzoylphosphine oxide, quinone-based compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethylanthraquinone, borate-based compounds, carbazole-based compounds, imidazole-based compounds, and titanocene-based compounds. Among these, oxime ester-based compounds are preferred.

The photopolymerization initiator (D) can be used alone or in combination of two or more types.

(Oxime ester compounds)
In oxime ester compounds, the N-O bond of the oxime is cleaved by absorbing ultraviolet light, generating iminyl radicals and alkyloxy radicals. These radicals further decompose to generate highly active radicals, allowing the formation of patterns with a small amount of exposure.

Examples of oxime ester compounds include oxime ester photopolymerization initiators described in JP-A-2007-210991, JP-A-2009-179619, JP-A-2010-037223, JP-A-2010-215575, JP-A-2011-020998, etc.

The content of the photopolymerization initiator (D) is preferably 1 to 10% by mass in the non-volatile content of the infrared absorbing composition. When an appropriate amount is added, the photocurability and developability are further improved.

<Sensitizer>
The infrared absorbing composition can contain a sensitizer.
Examples of the sensitizer include polymethine dyes such as chalcone derivatives, unsaturated ketones typified by dibenzalacetone, 1,2-diketone derivatives typified by benzil and camphorquinone, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, and oxonol derivatives, acridine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indoline derivatives, azulene derivatives, azulenium derivatives, squarylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, and tetrapyrazinoporphyrazine derivatives. , phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalyloporphyrazine derivatives, naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrylium derivatives, tetraphylline derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospiropyran derivatives, metal arene complexes, organic ruthenium complexes, or Michler's ketone derivatives, α-acyloxy esters, acylphosphine oxides, methylphenyl glyoxylate, benzyl, 9,10-phenanthrenequinone, camphorquinone, ethyl anthraquinone, 4,4'-diethylisophthalophenone, 3,3' or 4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 4,4'-bis(diethylamino)benzophenone, and the like.

Among these, thioxanthone derivatives, Michler's ketone derivatives, and carbazole derivatives are preferred, and 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(ethylmethylamino)benzophenone, N-ethylcarbazole, 3-benzoyl-N-ethylcarbazole, 3,6-dibenzoyl-N-ethylcarbazole, etc. are more preferred.

Sensitizers can be used alone or in combination of two or more types.

The content of the sensitizer is preferably 3 to 60 parts by mass, and more preferably 5 to 50 parts by mass, per 100 parts by mass of the photopolymerization initiator (D). When an appropriate amount is contained, the curing property and developability are further improved.

<Thermosetting Compound>
The infrared absorbing composition may contain a thermosetting compound. When the infrared absorbing composition is used to prepare a coating, the thermosetting compound is thermally cured in the heating step to increase the crosslink density of the coating and improve the heat resistance.

The thermosetting compound may be a low molecular weight compound or a high molecular weight compound such as a resin.
Examples of the thermosetting compound include epoxy compounds, oxetane compounds, benzoguanamine compounds, rosin-modified maleic acid compounds, rosin-modified fumaric acid compounds, melamine compounds, urea compounds, and phenol compounds. Among these, epoxy compounds and oxetane compounds are preferred.

<Thiol-based chain transfer agent>
The infrared absorbing composition may contain a thiol-based chain transfer agent. By using a thiol together with a photopolymerization initiator, the thiol acts as a chain transfer agent in the radical polymerization process after irradiation with light, and generates a thiyl radical that is not easily inhibited by oxygen, so that the obtained infrared absorbing composition has high sensitivity.

The thiol chain transfer agent is preferably a multifunctional thiol having two or more thiol groups (SH groups), and more preferably four or more. As the number of functional groups increases, the coating becomes easier to photocure from the surface to the deepest part.

Polyfunctional thiols include, for example, hexanedithiol and decanedithiol. , 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris(2-hydroxyethyl)isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine, etc. are included, and preferably, ethylene glycol bisthiopropionate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate, etc. are included.

Thiol-based chain transfer agents can be used alone or in combination of two or more types.

The content of the thiol chain transfer agent is preferably 0.1 to 10 mass %, and more preferably 0.1 to 3 mass %, based on 100 mass % of the nonvolatile content of the infrared absorbing composition. When an appropriate amount is included, the photosensitivity and taper shape are improved, and wrinkles are less likely to occur on the coating surface.

<Polymerization inhibitor>
The infrared absorbing composition may contain a polymerization inhibitor, which can suppress photosensitivity due to diffracted light from a mask during exposure in a photolithography method, making it easier to obtain a pattern with a desired shape.

Polymerization inhibitors include, for example, alkyl catechol compounds such as catechol, resorcinol, 1,4-hydroquinone, 2-methylcatechol, 3-methylcatechol, 4-methylcatechol, 2-ethylcatechol, 3-ethylcatechol, 4-ethylcatechol, 2-propylcatechol, 3-propylcatechol, 4-propylcatechol, 2-n-butylcatechol, 3-n-butylcatechol, 4-n-butylcatechol, 2-tert-butylcatechol, 3-tert-butylcatechol, 4-tert-butylcatechol, and 3,5-di-tert-butylcatechol; 2-methylresorcinol, 4-methylresorcinol, 2-ethylresorcinol, 4-ethylresorcinol, 2-propylresorcinol, 4-propylresorcinol, and 2-n-butylcatechol. Examples of such compounds include alkyl resorcinol compounds such as n-butyl resorcinol, 4-n-butyl resorcinol, 2-tert-butyl resorcinol, and 4-tert-butyl resorcinol; alkyl hydroquinone compounds such as methyl hydroquinone, ethyl hydroquinone, propyl hydroquinone, tert-butyl hydroquinone, and 2,5-di-tert-butyl hydroquinone; phosphine compounds such as tributyl phosphine, trioctyl phosphine, tricyclohexyl phosphine, triphenyl phosphine, and tribenzyl phosphine; phosphine oxide compounds such as trioctyl phosphine oxide and triphenyl phosphine oxide; phosphite compounds such as triphenyl phosphite and trisnonylphenyl phosphite; pyrogallol; and phloroglucin.

The content of the polymerization inhibitor is preferably 0.01 to 0.4 parts by mass based on 100% by mass of the non-volatile content of the infrared absorbing composition. In this range, the effect of the polymerization inhibitor becomes greater, and the linearity of the taper, wrinkles in the coating film, pattern resolution, etc. become better.

<Ultraviolet absorbing agent>
The infrared absorbing composition may contain an ultraviolet absorbing agent. Examples of the ultraviolet absorbing agent include benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, salicylic acid ester-based compounds, cyanoacrylate-based compounds, and salicylate-based compounds. The ultraviolet absorbing agent may be an oligomer or a polymer.

Benzotriazole compounds include, for example, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)-2H-benzotriazole, 2-[2-hydroxy-3,5-bis(α, α-Dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 5% 2-methoxy-1-methylethyl acetate and 95% benzenepropanoic acid, 3-(2H-benzotriazol-2-yl)-(1,1-dimethylethyl)-4-hydroxy, C7-9 branched and linear alkyl ester mixture, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, methyl 3-(3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate/polyethylene glycol 300 reaction products, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-t- Butyl-4-methylphenol, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate.

Examples of triazine compounds include 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-[3-(dodecyloxy)-2-hydroxypropoxy]phenol, and the reaction product of 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and (2-ethylhexyl)-glycidic acid ester. Examples of such compounds include 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-triazine, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

Examples of benzophenone compounds include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid-3-water, 2-hydroxy-4-n-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, 2,2'dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, and 2-hydroxy-4-methoxy-2'-carboxybenzophenone.

Examples of salicylic acid ester compounds include phenyl salicylate, p-octylphenyl salicylate, and p-tert-butylphenyl salicylate.

The content of the UV absorber is preferably 5 to 70% by mass, with the total of the photopolymerization initiator and the UV absorber being 100% by mass. If an appropriate amount is included, the resolution after development will be further improved.

In addition, the total content of the photopolymerization initiator and the ultraviolet absorber is preferably 1 to 20% by mass based on 100% by mass of the nonvolatile content of the infrared absorbing composition. When an appropriate amount is contained, the adhesion between the substrate and the coating is further improved, and good resolution can be obtained.

<Antioxidants>
The infrared absorbing composition may contain an antioxidant. The antioxidant prevents the photopolymerization initiator or thermosetting compound contained in the infrared absorbing composition from oxidizing and yellowing due to a thermal process such as heat curing, and therefore can improve the transmittance of the coating film. In particular, when the colorant concentration in the composition is high, the content of the photopolymerizable compound (D) is relatively reduced, so that the coating film is likely to yellow if the amount of the photopolymerization initiator is increased or a thermosetting compound is added. Therefore, by including an antioxidant, yellowing due to oxidation during the heating process can be prevented, and the decrease in the transmittance of the coating film can be suppressed.

Examples of antioxidants include hindered phenol-based, hindered amine-based, phosphorus-based, sulfur-based, and hydroxylamine-based compounds. In this specification, the antioxidant is preferably a compound that does not contain a halogen atom.

Among these, from the viewpoint of achieving both transmittance and sensitivity of the coating film, hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants are preferred.

Antioxidants can be used alone or in combination of two or more types.

The content of the antioxidant is more preferably 0.5 to 5.0% by mass based on 100% by mass of the non-volatile content of the infrared absorbing composition, since this provides good transmittance, spectral characteristics, and sensitivity.

<Leveling Agent>
The infrared absorbing composition may contain a leveling agent. This improves the wettability of the coating to the substrate during coating formation and the drying property of the coating. Examples of the leveling agent include silicone surfactants, fluorine surfactants, nonionic surfactants, cationic surfactants, and anionic surfactants.

Leveling agents can be used alone or in combination of two or more types.

The content of the leveling agent is preferably 0.001 to 2.0 mass % of the non-volatile content of the infrared absorbing composition, and more preferably 0.005 to 1.0 mass %. Within this range, the balance between the coatability, pattern adhesion, and transmittance of the infrared absorbing composition is further improved.

<Storage stabilizer>
The infrared absorbing composition may contain a storage stabilizer to stabilize the viscosity of the composition over time. Examples of the storage stabilizer include quaternary ammonium chlorides such as benzyl trimethyl chloride and diethylhydroxyamine, organic acids such as lactic acid and oxalic acid and their methyl ethers, organic phosphines such as t-butylpyrocatechol, tetraethylphosphine and tetraphenylphosphine, and phosphites.

The content of the storage stabilizer is preferably 0.1 to 10% by mass per 100 parts by mass of the squarylium dye (A).

<Adhesion improver>
The infrared absorbing composition may contain an adhesion improver. This improves the adhesion between the coating and the substrate. It also makes it easier to form narrow patterns by photolithography. Examples of the adhesion improver include silane coupling agents.

Adhesion improvers include vinyl silanes such as vinyltrimethoxysilane and vinyltriethoxysilane, (meth)acrylic silanes such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane, epoxy silanes such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane. Examples of silane coupling agents include aminosilanes such as N-propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride; mercaptos such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; styryls such as p-styryltrimethoxysilane; ureidos such as 3-ureidopropyltriethoxysilane; sulfides such as bis(triethoxysilylpropyl)tetrasulfide; and isocyanates such as 3-isocyanatepropyltriethoxysilane.

The content of the adhesion enhancer is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of squarylium (A). When an appropriate amount is contained, the photosensitivity of the infrared absorbing composition is improved, the adhesion of the coating is further improved, and the resolution of the pattern is also further improved.

<Method for producing infrared absorbing composition>
The infrared absorbing composition is prepared by dispersing the squarylium compound (A), a solvent, and, if necessary, a dispersant, etc., to prepare a dispersion. Then, the binder resin (B), the polymerizable compound (C), and the photopolymerization initiator (D) are mixed together to prepare the composition. The timing of mixing each material is arbitrary.

The dispersion process can be carried out using a dispersion device such as a kneader, a two-roll mill, a three-roll mill, a ball mill, a horizontal sand mill, a vertical sand mill, an annular bead mill, or an attritor.

<Solvent>
The infrared absorbing composition may contain a solvent. This makes it easier to adjust the viscosity of the composition, and therefore easier to form a coating with a smooth surface. The solvent may be appropriately selected depending on the purpose of use, and an appropriate amount may be contained.

Examples of solvents include ester solvents (solvents that contain -COO- in the molecule but do not contain -O-), ether solvents (solvents that contain -O- in the molecule but do not contain -COO-), ether ester solvents (solvents that contain -COO- and -O- in the molecule), ketone solvents (solvents that contain -CO- in the molecule but do not contain -COO-), alcohol solvents (solvents that contain OH in the molecule but do not contain -O-, -CO- or -COO-), aromatic hydrocarbon solvents, amide solvents, dimethyl sulfoxide, etc.

Among these, solvents with a boiling point of 120°C or more and 180°C or less at 1 atm are preferred in terms of coatability and drying properties. For example, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether, ethyl 3-ethoxypropionate, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, 4-hydroxy-4-methyl-2-pentanone, N,N-dimethylformamide, N-methylpyrrolidone, etc. are more preferred, and propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, ethyl 3-ethoxypropionate, etc. are even more preferred.

<Removal of coarse particles>
The infrared absorbing composition is preferably subjected to removal of coarse particles of 5 μm or more, preferably coarse particles of 1 μm or more, and more preferably coarse particles of 0.5 μm or more, and mixed dust, by means of centrifugation at a gravitational acceleration of 3,000 to 25,000 G, filtration with a sintered filter or membrane filter, etc. In this way, it is preferable that the infrared absorbing composition does not substantially contain particles of 0.5 μm or more. More preferably, the particles are 0.3 μm or less.

The optical filter of the present invention preferably has a substrate and a film formed from an infrared absorbing composition.
The type of the substrate may be, for example, glass, silicon wafer, etc. The thickness of the substrate is about 0.3 to 2 mm.
The thickness of the film is about 0.2 to 5 μm.

<Method of Manufacturing Optical Filter>
The optical filter of the present invention can be prepared by forming a coating (film) on a substrate. The film can be formed into a desired pattern by, for example, a photolithography method.

For the pattern by the photolithography method, the infrared absorbing composition prepared as the solvent-developable or alkali-developable resist material is applied to a transparent substrate by a known method such as spray coating, spin coating, slit coating, or roll coating. The film, which has been dried as necessary, is exposed to ultraviolet light through a mask having a predetermined pattern that is provided in contact with or out of contact with the film. Thereafter, the uncured parts are removed by immersing the film in a solvent or alkali developer or spraying the developer with a spray or the like to form a desired pattern, and the same operation is repeated for other colors to produce a filter. Furthermore, heating can be performed as necessary to promote polymerization of the polymerizable unsaturated groups. According to the photolithography method, a filter with higher precision can be produced than by the printing method.

For development, an aqueous solution of sodium carbonate, sodium hydroxide, etc. is used as an alkaline developer, and organic alkalis such as dimethylbenzylamine, triethanolamine, etc. can also be used. Antifoaming agents and surfactants can also be added to the developer.

In addition to the above method, the optical filter of the present invention can be manufactured by a printing method, an etching method, an electrodeposition method, a transfer method, an inkjet method, etc.

<Applications of optical filters>
The optical filter of the present invention has a wide viewing angle and excellent infrared blocking ability. Therefore, it is preferable to use it as an infrared blocking filter. In addition, it has little absorption in the visible range (400 nm to 700 nm), excellent infrared absorbing ability, and excellent durability such as heat resistance and light resistance. Therefore, it is useful for visual sensitivity correction of solid-state imaging elements such as CCD and CMOS image sensors of camera modules. In particular, it is useful for digital still cameras, mobile phone cameras, digital video cameras, PC cameras, surveillance cameras, automobile cameras, televisions, car navigation systems, personal digital assistants, personal computers, video games, portable game machines, sensors for biometric authentication (fingerprint authentication and vein authentication), digital music players, etc.

For example, when capturing an image, a digital camera recognizes color by breaking down the light it receives into red, green, and blue filters and sending it to a photodiode that converts the light into an electrical signal. Photodiodes also react to infrared light and convert it into an electrical signal, so a filter is needed to block this. The optical filter of the present invention can be used as a filter to block this infrared light. Absorption in the visible range in addition to infrared light has a negative effect on color recognition, but the squarylium compound (A) is highly invisible and therefore has little negative effect on the color recognition of the photodiode.

(Biometric sensor)
The optical filter of the present invention can also be used in sensors for biometric authentication (fingerprint authentication or vein authentication), or in touch sensors or touch panels incorporating such sensors.
For example, biometric authentication functions such as fingerprint authentication and finger vein authentication are installed in smartphones, tablet PCs, bank ATMs, multimedia terminals, and the like for security purposes.
Fingerprint authentication technology, particularly for use in smartphones and tablet PCs, has been developing at a dizzying pace, and with the increase in screen size (to full screen), fingerprint authentication sensors built into displays have been developed for both organic EL displays and liquid crystal displays.
However, most fingerprint sensors built into displays use an optical system that shines various light sources inside the display onto the fingerprint and senses the reflected light, so if unauthorized external light (strong light with a wide range of wavelengths, such as sunlight or LED lighting) enters the sensor, it becomes noise when capturing an image, which makes the accuracy somewhat unreliable for outdoor use. The same is true for finger vein authentication in bank ATMs and multimedia terminals, and in stores with strong lighting or good sunlight, measures are taken to block external light, such as putting a cover over the sensor.
The optical filter of the present invention is effective in solving these problems by absorbing and preventing unauthorized external light from being incident on the sensor.
For example, when used in a smartphone or tablet computer, when it is set on the front of the panel, it is necessary to have a design that is also attractive, and the optical filter of the present invention has the advantage that it can be used suitably because it has no absorption in the visible range and is invisible, i.e., highly transparent. In addition, the optical filter of the present invention has excellent heat resistance, so it can also be used favorably in the process of manufacturing a sensor, or a touch sensor or touch panel in which the sensor is incorporated.

(display)
The optical filter of the present invention can also be incorporated into a display. Specifically, a liquid crystal display with a touch panel function such as an electronic whiteboard can be mentioned. This liquid crystal display with a touch panel function has three functions of display, writing, and storage, and the touch panel built into it also employs optical methods such as an infrared scanning method and an infrared projection method, and the noise caused by the above-mentioned external light is an issue. Liquid crystal displays with a touch panel function are often used in schools, etc., so their accuracy and good response to touch are important. By incorporating the optical filter of the present invention into a display, external light that becomes noise can be cut. In addition, the optical filter of the present invention can be preferably used as an anti-reflection film for large displays such as organic electroluminescence (OLED) televisions. By suppressing the reflection of not only visible light but also light in the infrared region, there is an advantage that the black display on the display can be made darker. The optical filter of the present invention has excellent heat resistance, so it can be preferably used for the resistance of processes required in display manufacturing.

The present invention will be described below based on manufacturing examples and examples, but the present invention is not limited thereto. In addition, "parts" means "parts by mass" and "%" means "% by mass."

(Method of Identifying Squarylium Compound (A))
The squarylium compound (A) used in the present invention was identified by MALDI TOF-MS spectrometry using a Bruker Daltonics MALDI mass spectrometer AutoflexIII, and the compound was identified based on the agreement between the molecular ion peak of the mass spectrum obtained and the mass number obtained by calculation.

(Weight average molecular weight (Mw) of basic resin-type dispersant and binder resin)
The weight average molecular weight (Mw) of the basic resin-type dispersant and the binder resin is a polystyrene-equivalent weight average molecular weight (Mw) measured using a TSKgel column (manufactured by Tosoh Corporation) and a GPC (manufactured by Tosoh Corporation, HLC-8120GPC) equipped with an RI detector, using THF as a developing solvent.

(Amine value of basic resin type dispersant)
The amine value (mgKOH/g) of the basic resin-type dispersant was measured using a 0.1N aqueous hydrochloric acid solution.
The amine value was determined by potentiometric titration and then converted into the equivalent amount of potassium hydroxide. The amine value of the basic resin-type dispersant indicates the amine value of the non-volatile content.

(Quaternary Ammonium Salt Value of Basic Resin Type Dispersant)
The quaternary ammonium salt value (mg KOH/g) of the basic resin type dispersant was determined by titration with 0.1 N silver nitrate aqueous solution using 5% potassium chromate aqueous solution as an indicator, and then converted into the potassium hydroxide equivalent. The quaternary ammonium salt value of the basic resin type dispersant indicates the quaternary ammonium salt value of the non-volatile content.

(Acid value of binder resin)
The acid value (mgKOH/g) of the binder resin was determined by potentiometric titration using a 0.1 N potassium hydroxide-ethanol solution. The acid value of the binder resin indicates the acid value of the non-volatile content.

<Method for producing squarylium compound (A)>
(Production of squarylium compound [A-1])
400 parts of toluene, 40.0 parts of 1,8-diaminonaphthalene, 25.1 parts of cyclohexanone, and 0.087 parts of p-toluenesulfonic acid monohydrate were mixed, heated and stirred in a nitrogen gas atmosphere, and refluxed for 3 hours. Water produced during the reaction was removed from the system by azeotropic distillation.
After the reaction was completed, the dark brown solid obtained by distilling toluene was extracted with acetone and purified by recrystallization from a mixed solvent of acetone and ethanol. The obtained brown solid was dissolved in a mixed solvent of 240 parts of toluene and 160 parts of n-butanol, and 13.8 parts of 3,4-dihydroxy-3-cyclobutene-1,2-dione was added, and the mixture was heated and stirred in a nitrogen gas atmosphere to cause a reflux reaction for 8 hours. Water generated during the reaction was removed from the system by azeotropic distillation.
After the reaction was completed, the solvent was distilled, and 200 parts of hexane was added to the resulting reaction mixture while stirring. The resulting black-brown precipitate was filtered off, washed successively with hexane, ethanol, and acetone, and dried under reduced pressure to obtain 61.9 parts of squarylium compound [A-1] (yield: 92%). As a result of mass analysis by TOF-MS, it was identified as squarylium compound [A-1].

Squarylium compound [A-1]

(Production of squarylium compound [A-2])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 32.2 parts of 2,6-dimethylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 71.9 parts of squarylium compound [A-2] (yield: 97%). As a result of mass analysis by TOF-MS, the squarylium compound [A-2] was identified.

Squarylium compound [A-2]

(Production of squarylium compound [A-3])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 32.2 parts of 3,5-dimethylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 72.6 parts of squarylium compound [A-3] (yield: 98%). As a result of mass analysis by TOF-MS, the squarylium compound [A-3] was identified.

Squarylium compound [A-3]

(Production of squarylium compound [A-4])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 28.6 parts of 4-methylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 67.2 parts of squarylium compound [A-4] (yield: 95%). As a result of mass analysis by TOF-MS, the squarylium compound [A-4] was identified as squarylium compound [A-4].

Squarylium compound [A-4]

(Production of squarylium compound [A-5])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 35.8 parts of 3,3,5-trimethylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 71.3 parts of squarylium compound [A-5] (yield: 92%). As a result of mass analysis by TOF-MS, the squarylium compound was identified as squarylium compound [A-5].

Squarylium compound [A-5]

(Production of squarylium compound [A-6])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 39.4 parts of 3,5-diethylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 76.9 parts of squarylium compound [A-6] (yield: 95%). As a result of mass analysis by TOF-MS, the squarylium compound was identified as squarylium compound [A-6].

Squarylium compound [A-6]

(Production of squarylium compound [A-7])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 39.4 parts of 5-isopropyl-2-methylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 76.9 parts of squarylium compound [A-7] (yield: 95%). As a result of mass analysis by TOF-MS, the squarylium compound [A-7] was identified.

Squarylium compound [A-7]

(Production of squarylium compound [A-8])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 46.0 parts of 2-cyclohexylcyclohexanone was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 79.4 parts of squarylium compound [A-8] (yield: 91%). As a result of mass analysis by TOF-MS, the squarylium compound was identified as squarylium compound [A-8].

Squarylium compound [A-8]

(Production of squarylium compound [A-9])
The same procedure as in the production of the squarylium compound [A-1] was carried out, except that 28.1 parts of 2-norbornanone was used instead of 25.1 parts of cyclohexanone used in the production of the squarylium compound [A-1], to obtain 64.6 parts of a squarylium compound [A-9] (yield: 92%). As a result of mass analysis by TOF-MS, the squarylium compound [A-9] was identified.

Squarylium compounds [A-9]

(Production of squarylium compound [A-10])
The same procedure as in the production of squarylium compound [A-1] was carried out, except that 42.5 parts of spiro[5.5]undecane-1-one was used instead of 25.1 parts of cyclohexanone used in the production of squarylium compound [A-1], to obtain 78.8 parts of squarylium compound [A-10] (yield: 94%). As a result of mass analysis by TOF-MS, the squarylium compound was identified as squarylium compound [A-10].

Squarylium compound [A-10]

(Production of squarylium compound [A-11])
400 parts of toluene were mixed with 40.0 parts of 1,8-diaminonaphthalene, 46.0 parts of 9-fluorenone, and 0.087 parts of p-toluenesulfonic acid monohydrate, and the mixture was heated and stirred in a nitrogen gas atmosphere and refluxed for 3 hours. Water generated during the reaction was removed from the system by azeotropic distillation. After the reaction was completed, the dark brown solid obtained by distilling toluene was extracted with acetone and purified by recrystallization from a mixed solvent of acetone and ethanol. The obtained brown solid was dissolved in a mixed solvent of 240 parts of toluene and 160 parts of n-butanol, 13.8 parts of 3,4-dihydroxy-3-cyclobutene-1,2-dione was added, and the mixture was heated and stirred in a nitrogen gas atmosphere and refluxed for 8 hours. Water generated during the reaction was removed from the system by azeotropic distillation. After the reaction was completed, the solvent was distilled, and 200 parts of hexane was added while stirring the resulting reaction mixture. The resulting black-brown precipitate was filtered off, washed successively with hexane, ethanol and acetone, and dried under reduced pressure to obtain 84.6 parts (yield: 97%) of squarylium compound (A-11), which was identified as squarylium compound (A-11) by mass spectrometry and elemental analysis using TOF-MS.

Squarylium compound [A-11]

(Synthesis of squarylium compound (A-12))
The same procedure as in the synthesis of squarylium compound (A-11) was carried out, except that 80.7 parts of 2,7-bis(trifluoromethyl)-9-fluorenone was used instead of 46.0 parts of 9-fluorenone used in the synthesis of squarylium compound (A-11), to obtain 109.8 parts of squarylium compound (A-12) (yield: 91%). As a result of mass spectrometry and elemental analysis by TOF-MS, the compound was identified as squarylium compound (A-12).

Squarylium compound [A-12]

(Synthesis of squarylium compound (A-13))
The same procedure as in the synthesis of squarylium compound (A-11) was carried out, except that 50.1 parts of 2-hydroxy-9-fluorenone was used instead of 46.0 parts of 9-fluorenone used in the synthesis of squarylium compound (A-11), to obtain 83.9 parts of squarylium compound (A-13) (yield: 92%). As a result of mass spectrometry and elemental analysis by TOF-MS, the squarylium compound was identified as squarylium compound (A-13).

Squarylium compounds [A-13]

<Method for producing binder resin (B) solution>
(Production Example 1: Production of binder resin (B1-1) solution)
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was charged with 160 parts of propylene glycol monomethyl ether acetate, and the atmosphere in the flask was changed from air to nitrogen. After heating to 100 ° C., a solution of 3.6 parts of azobisisobutyronitrile was added to a mixture of 96.0 parts (0.55 mol) of benzyl methacrylate (BzMA), 17.6 parts (0.21 mol) of methacrylic acid (MAA), 22.0 parts (0.10 mol) of tricyclodecane skeleton-containing methacrylate (Hitachi Chemical Co., Ltd. FA-513M) and 140 parts of propylene glycol monomethyl ether acetate was added dropwise from the dropping funnel to the flask over 2 hours, and the mixture was stirred at 100 ° C. for 5 hours to obtain a solution of an acrylic resin with an acid value of 85 mg KOH / g and a weight average molecular weight (Mw) of 8,000. After cooling to room temperature, about 2 g of the resin solution was sampled and dried by heating at 180°C for 20 minutes to measure the non-volatile content. Propylene glycol monomethyl ether acetate was added to the previously synthesized resin solution so that the non-volatile content was 20% by weight, thereby preparing a binder resin (B1-1) solution.

(Production Examples 2 to 6: Production of binder resin (B1-2 to 5, B2-1) solutions)
Binder resin (B1-2 to B1-5, B2-1) solutions were prepared in the same manner as in Production Example 1, except that the materials and amounts added were changed as shown in Table 1. The theoretical values of the glass transition temperatures (Tg) of each were also shown in Table 1. Styrene is (St), and methyl methacrylate is (MMA).

(Production Example 7: Production of binder resin (B2-2) solution)
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was charged with 160 parts of propylene glycol monomethyl ether acetate, and the atmosphere in the flask was changed from air to nitrogen. The temperature was then raised to 100°C, after which a solution of 96.0 parts (0.55 mol) of benzyl methacrylate, 17.6 parts (0.21 mol) of methacrylic acid, 22.0 parts (0.10 mol) of a tricyclodecane-based monomethacrylate (FA-513M manufactured by Hitachi Chemical Co., Ltd.) and 140 parts of propylene glycol monomethyl ether acetate to which 3.6 parts of azobisisobutyronitrile had been added was dropped into the flask from the dropping funnel over 2 hours, and the mixture was further stirred at 100°C for 5 hours. Next, the atmosphere in the flask was changed from nitrogen to air, and 21.3 parts [0.15 moles] of glycidyl methacrylate, 0.9 parts of trisdimethylaminomethylphenol and 0.145 parts of hydroquinone were added to the flask, and the reaction was continued for 6 hours at 110 ° C. to obtain a resin solution (B2-2) with a non-volatile content of 37.6% and an acid value of 67.7 mg KOH / g (non-volatile content equivalent). The weight average molecular weight of the polystyrene equivalent measured by GPC was 9,500 to obtain an acrylic resin solution. After cooling to room temperature, about 2 g of the resin solution was sampled and dried at 180 ° C. for 20 minutes to measure the non-volatile content, and propylene glycol monomethyl ether acetate was added to the resin solution synthesized earlier so that the non-volatile content was 20 wt% to prepare a binder resin (B2-2) solution.

<Method for producing resin-type dispersant (E)>
(Resin-type dispersant (E-1 to E-4) solutions)
The basic resin-type dispersant described in JP 2019-211764 A was used as shown in Table 2 below.

<Production of infrared absorbing composition>
(Infrared absorbing composition (IRP-1))
A mixture of the following composition was stirred and mixed uniformly, dispersed in an Eiger mill using zirconia beads having a diameter of 0.5 mm for 3 hours, and then filtered through a 0.5 μm filter to prepare an infrared absorbing composition.
Squarylium compound (A-1): 10.0 parts Binder resin (B1-1) solution: 35.0 parts Resin type dispersant (E-1) solution: 7.5 parts Solvent (N): 47.5 parts

(Infrared absorbing compositions (IRP-2 to 19))
Infrared absorbing compositions (IRP-2 to 22) were prepared in the same manner as infrared absorbing composition (IRP-1), except that the squarylium compound, the resin-type dispersant solution, the binder resin solution, and the solvent were changed to the compositions and amounts shown in Table 3.

Dye derivative (b0-1)

<Preparation of Photosensitive Infrared Absorbing Composition (IRR-1)>
[Example 1]
The following mixture was stirred and mixed to a uniform consistency, and then filtered through a 1.0 μm filter to obtain a photosensitive infrared absorbing composition (IRR-1).
Infrared absorbing composition (IRP-1: non-volatile content 20%): 75.0 parts Binder resin (B1-1: non-volatile content 20%) solution: 5.0 parts Thermosetting compound (BE-1): 0.5 parts Thermosetting compound (BE-2): 0.5 parts Polymerizable compound (C): 2.0 parts Photopolymerization initiator (D): 1.8 parts Sensitizer (F): 0.2 parts Thiol-based chain transfer agent (G): 0.4 parts Polymerization inhibitor (H): 0.05 parts Ultraviolet absorber (I): 0.15 parts Antioxidant (J): 0.1 parts Leveling agent (K: non-volatile content 3%): 1.0 parts Storage stabilizer (L): 0.1 parts Silane coupling agent (M): 0.2 parts Solvent (N): 13.0 parts

[Examples 2 to 24, Comparative Example 1]
Hereinafter, photosensitive infrared absorbing compositions (IRR-2 to 25) were obtained in the same manner as infrared absorbing composition (IRR-1), except that the compositions and blending amounts were changed to those shown in Table 4.

<Thermosetting compound (BE)>
Epoxy compound (BE-1)
(BE-1-1) 1,2- of 2,2'-bis(hydroxymethyl)-1-butanol
Epoxy-4-(2-oxiranyl)cyclohexane adduct
[EHPE-3150 (manufactured by Daicel)],
(BE-1-2) Glycidyl etherified epoxy compound of sorbitol
[Denacol EX611 (manufactured by Nagase Chemtex Corporation)],
(BE-1-3) Triglycidyl isocyanurate (BE-1-1) to (BE-1-3) were mixed in equal amounts to prepare an epoxy compound (BE-1).
Oxetane compound (BE-2):
3-Ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane
[Aron Oxetane OXT-221 (manufactured by Toagosei)]

<Polymerizable compound (C)>
(C-1) Trimethylolpropane triacrylate
[Aronix M309 (manufactured by Toagosei Co., Ltd.)]; trifunctional (C-2) dipentaerythritol penta- and hexaacrylate (E-2)
[Aronix M402 (manufactured by Toagosei Co., Ltd.)]; a mixture of pentafunctional and hexafunctional (C-3) polybasic acidic acrylic oligomer
[Aronix M520 (manufactured by Toagosei)]
(C-4) Caprolactone-modified dipentaerythritol hexaacrylate
[KAYARAD DPCA-30 (manufactured by Nippon Kayaku Co., Ltd.)]; 6 functional groups

(C-5) Multifunctional urethane acrylate as described below: Pentaerythritol triacrylate (432 parts) and 84 parts of hexamethylene diisocyanate were charged into a 1-liter five-necked reaction vessel and reacted at 60°C for 8 hours to obtain a product containing a multifunctional urethane acrylate (C-5) having a (meth)acryloyl group. The proportion of the multifunctional urethane acrylate (C-5) in the product was 70 mass%, with the remainder being other photopolymerizable monomers. It was confirmed by IR analysis that no isocyanate groups were present in the reaction product.

(C-6) Difunctional bisphenol A type (meth)acrylate
[ABE-300 (manufactured by Shin-Nakamura Chemical Co., Ltd.)]
(C-7) Ethoxylated isocyanuric acid triacrylate
[A-9300 (manufactured by Shin-Nakamura Chemical Co., Ltd.)]
The above (C-1) to (C-7) were mixed in equal amounts to obtain a polymerizable compound (C).

<Photopolymerization initiator (D)>
(D-1) 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one
[Irgacure 907 (manufactured by BASF Japan)]
(D-2) 2-(Dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone
[Irgacure 379 (manufactured by BASF Japan)]
(D-3) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide
[Lucirin TPO (manufactured by BASF Japan)]
(D-4) 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetraphenyl-1,2'-biimidazole
[Biimidazole (Kurokane Chemicals)]
(D-5) p-Dimethylaminoacetophenone
[DMA (manufactured by Daikifine)]
(D-6) Ethan-1-one, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl], 1-(O-acetyloxime)
[Irgacure OXE02 (manufactured by BASF Japan)]
(D-7) 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one
[Irgacure 2959 (manufactured by BASF Japan)]
(D-8) Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide
[Irgacure 819 (manufactured by BASF Japan)]
The above (D-1) to (D-8) were mixed in equal amounts to prepare a photopolymerization initiator (D).

<Sensitizer (F)>
(F-1) 2,4-diethylthioxanthone
[Kayacure DETX-S (manufactured by Nippon Kayaku)]
(F-2) 4,4'-bis(diethylamino)benzophenone
[CHEMARK DEABP (manufactured by Chemark Chemical)]
The above (F-1) and (F-2) were mixed in equal amounts to prepare sensitizer (F).

<Thiol-Based Chain Transfer Agent (G)>
(G-1) Trimethylolethane tris(3-mercaptobutyrate)
[TEMB (Showa Denko)]
(G-2) Trimethylolpropane tris(3-mercaptobutyrate)
[TPMB (Showa Denko)]
(G-3) Pentaerythritol tetrakis(3-mercaptopropionate)
[PEMP (manufactured by Sakai Chemical Industry Co., Ltd.)]
(G-4) Trimethylolpropane tris(3-mercaptopropionate)
[TMMP (manufactured by Sakai Chemical Industry Co., Ltd.)]
(G-5) Tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate
[TEMPIC (manufactured by Sakai Chemical Industry Co., Ltd.)]
The above (G-1) to (G-5) were mixed in equal amounts to prepare a thiol-based chain transfer agent (G).

<Polymerization Inhibitor (H)>
(H-1) 3-methylcatechol (H-2) methylhydroquinone (H-3) t-butylhydroquinone The above (H-1) to (H-3) were mixed in equal amounts to prepare a polymerization inhibitor (H).

<Ultraviolet absorber (I)>
(I-1) 2-[4-[(2-hydroxy-3-(dodecyl and tridecyl)oxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine
[TINUVIN 400 (manufactured by BASF Japan)]
(I-2) 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol
[TINUVIN900 (manufactured by BASF Japan)]
The above (I-1) and (I-2) were mixed in equal amounts to prepare an ultraviolet absorber (I).

<Antioxidant (J)>
(J-1) pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (J-2) dioctadecyl 3,3'-thiodipropanoate (J-3) tris[2,4-di-(t)-butylphenyl]phosphine (J-4) bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (J-5) p-octylphenyl salicylate The above (J-1) to (J-5) were mixed in equal amounts to prepare antioxidant (J).

<Leveling Agent (K)>
1 copy of BYK-330 manufactured by BYK,
1 copy of DIC "Megafac F-551"
A mixed solution of 1 part of Kao Corporation's "Emulgen 103" dissolved in 97 parts of PGMAc.

<Storage stabilizer (L)>
(L-1) 2,6-bis(1,1-dimethylethyl)-4-methylphenol ("BHT" manufactured by Honshu Chemical Industry Co., Ltd.)
(L-2) Triphenylphosphine ("TPP" manufactured by Hokko Chemical Industry Co., Ltd.)
The above (L-1) and (L-2) were mixed in equal amounts to prepare a storage stabilizer (L).

<Adhesion improver (M)>
(M-1) 3-glycidoxypropyltriethoxysilane
[Shin-Etsu Silicone Silane Coupling Agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)]
(M-2) 3-Methacryloxypropyltriethoxysilane
[Shin-Etsu Silicone Silane Coupling Agent KBE-503 (manufactured by Shin-Etsu Chemical Co., Ltd.)]
(M-3) N-2-(aminoethyl)-3-aminopropyltrimethoxysilane
[Shin-Etsu Silicone Silane Coupling Agent KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd.)]
(M-4) 3-mercaptopropyltrimethoxysilane
[Shin-Etsu Silicone Silane Coupling Agent KBM-803 (manufactured by Shin-Etsu Chemical Co., Ltd.)]
The above (M-1) to (M-4) were mixed in equal amounts to prepare a silane coupling agent (M).

<Solvent (N)>
(N-1) PGMAc 30 parts (N-2) Cyclohexanone 30 parts (N-3) Ethyl 3-ethoxypropionate 10 parts (N-4) Propylene glycol monomethyl ether 10 parts (N-5) Cyclohexanol acetate 10 parts (N-6) Dipropylene glycol methyl ether acetate 10 parts The above (N-1) to (N-6) were mixed in the above parts by mass to obtain solvent (N).

<Evaluation of infrared absorbing composition>
The photosensitive infrared absorbing compositions obtained in the Examples and Comparative Examples were tested for average primary particle size, spectral characteristics, resistance (light resistance, heat resistance), pattern peeling property, development speed, and pattern formability by the following methods. ⊚ indicates a very good level, ◯ indicates a good level, △ indicates a practical level, and × indicates a level not suitable for practical use. The results are shown in Table 5.

(Evaluation of Spectral Characteristics)
The obtained photosensitive infrared absorbing composition was spin-coated on a 1.1 mm thick glass substrate using a spin coater to a film thickness of 1.0 μm, dried at 60° C. for 5 minutes, and then heated at 230° C. for 5 minutes to prepare a substrate with a coating film. The spectrum of the obtained substrate with a coating film was measured using a spectrophotometer (U-4100, Hitachi High-Technologies Corporation) in the wavelength range of 300 to 900 nm. The average absorbance of 400 to 700 nm, when the absorbance of the maximum absorption wavelength is set to 1, was evaluated according to the following criteria. The maximum absorption wavelength of the squarylium compound (A) is in the infrared region (700 to 1000 nm). When this absorbance is set to 1, the smaller the absorbance of 400 to 700 nm, the more excellent the absorption ability in the infrared region, and the higher the coloring power and the steeper the spectrum.
◎: Less than 0.05 ○: 0.05 or more, less than 0.075 △: 0.075 or more, less than 0.1 ×: 0.1 or more

(Lightfastness test)
A substrate with a coating film was prepared using the same procedure as in the spectral characteristic evaluation, and placed in a light resistance tester (TOYOSEIKI's "SUNTEST CPS+") and left for 24 hours. The absorbance at the spectral maximum absorption wavelength of the coating film was measured, and the remaining ratio to that before light irradiation was calculated, and the light resistance was evaluated according to the following criteria. The remaining ratio was calculated using the following formula.
Residual rate = (absorbance after irradiation) ÷ (absorbance before irradiation) × 100
◎: Residual rate is 95% or more. ○: Residual rate is 90% or more, but less than 95%. ×: Residual rate is less than 90%.

(Heat resistance test)
A substrate with a coating film was prepared using the same procedure as in the spectral characteristic evaluation, and was additionally heated at 210° C. for 20 minutes as a heat resistance test. The absorbance at the spectral maximum absorption wavelength of the coating film was measured, and the remaining ratio to that before the heat resistance test was calculated, and the heat resistance was evaluated according to the following criteria. The remaining ratio was calculated using the following formula.
Residual rate = (absorbance after heat resistance test) ÷ (absorbance before heat resistance test) × 100
◎: Residual rate is 95% or more. ○: Residual rate is 90% or more, but less than 95%. ×: Residual rate is less than 90%.

(Residual film after development)
The compositions obtained in Examples 1 to 24 and Comparative Example 1 were spin-coated on a glass substrate using a spin coater so that the dry film thickness was 1.0 μm, and then dried at 70 for 3 minutes to prepare a substrate with a coating film. The obtained coating film was exposed to light at 20,000 W/5,000 J using a stepper exposure machine (ATS-4003, manufactured by Asahi Techno Solutions Co., Ltd.), and the film thickness of the exposed area was measured with a contact film thickness meter (DEKTAC8, stylus surface profiler, manufactured by ULVAC, Inc.), and the film thickness after immersion in a 2% potassium hydroxide aqueous solution for 2 minutes was then measured, and the amount of film loss after development (development remaining film rate) was evaluated based on the ratio of the measured film thicknesses.
Residual film after development (%) = film thickness after immersion in developer / film thickness before immersion in developer × 100%
The evaluation ranking is as follows:
◎: 90% or more 〇: 70% or more, less than 90% △: 50% or more, less than 70% ×: Less than 50%

Claims (7)

The present invention comprises a squarylium compound (A), a binder resin (B), a polymerizable compound (C) and a photopolymerization initiator (D),
The acid value of the binder resin (B) is 85 to 130 mgKOH/g;
The binder resin (B) includes a binder resin (B1) having a monomer unit (b1) having one or more skeletons selected from a tricyclodecane skeleton and a dicyclopentadiene skeleton in one molecule, and a carboxyl group-containing monomer unit (b2), and having no polymerizable unsaturated group;
The glass transition temperature of the binder resin (B1) is 85.9 to 109.7 ° C.;
Infrared absorbing composition. The infrared absorbing composition according to claim 1, wherein the photopolymerization initiator (D) is contained in an amount of 1 to 10 mass % in the nonvolatile content of the infrared absorbing composition. The infrared absorbing composition according to claim 1 or 2, further comprising a basic resin-type dispersant (E). The infrared absorbing composition according to claim 3, wherein the amine value of the basic resin-type dispersant (E) is 50 to 100 mg KOH/g. The infrared absorbing composition according to claim 3 or 4, wherein the basic resin-type dispersant (E) is a dispersant having an amino group and a quaternary ammonium salt group. The infrared absorbing composition according to any one of claims 1 to 5, wherein the photopolymerizable compound (C) includes a compound having three polymerizable unsaturated groups. An optical filter comprising a substrate and a film formed from the infrared absorbing composition according to any one of claims 1 to 6.