JP7570169B2 - Curable Composition - Google Patents

Description

The present invention relates to a curable composition.

Video cameras, digital cameras, mobile phones with camera functions, and the like are equipped with solid-state imaging elements, which are optical sensors. Specific examples of solid-state imaging elements that are widely used include CCD (Charge-Coupled Device) image sensors and CMOS (Complementary MOS) image sensors. The sensitivity of the photodiodes in these solid-state imaging elements ranges from the ultraviolet region close to visible light to the infrared region. For this reason, solid-state imaging elements are provided with optical filters to block ultraviolet and infrared rays close to the visible light region. These optical filters can correct the sensitivity of the solid-state imaging element to approach the visual sensitivity of humans. In addition to solid-state imaging elements, optical filters that block ultraviolet rays and the like are used for various purposes.

To form an optical filter, for example, a composition containing components such as a dye for blocking light of a specific wavelength, a polymerizable compound, and a polymerization initiator is used (see Patent Document 1). Such a composition is applied and cured to form an optical filter.

JP 2013-228433 A

In optical filters for blocking light rays in the ultraviolet region, optical filters with higher ultraviolet blocking properties are desired. However, conventional optical filters can have defects such as foreign matter. Defects in optical filters can affect visible light transmittance, blocking properties, etc. Furthermore, optical filters may also be required to be heat resistant, for example, so that their transmittance and blocking properties do not decrease even when used at high temperatures.

The present invention was made based on the above circumstances, and its purpose is to provide a curable composition that can form an optical filter that has good blocking properties for ultraviolet rays close to the visible light region, good transmittance and heat resistance for visible light, and few defects such as foreign matter.

（式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して、炭素数１～３０の１価の有機基である。Ｒ^４及びＲ^５は、それぞれ独立して、炭素数１～３０の１価の有機基又はハロゲン原子である。ａ及びｂは、それぞれ独立して、０～３の整数である。ａが２以上の場合、複数のＲ^４は、同一でも異なっていてもよい。ｂが２以上の場合、複数のＲ^５は、同一でも異なっていてもよい。）

（式（２）中、Ａは、１又は複数の五員環又は六員環から構成される環構造である。Ｒ^６は、ハロゲン原子、ヒドロキシ基、ニトロ基又は炭素数１～４０の１価の有機基である。Ｒ^７は、＊－ＣＯ－、＊－ＣＯＯ－、＊－ＳＣＯ－、＊－ＣＯＳ－、＊－Ｓ－ＣＯＯ－、＊－ＣＯＮＨ－、＊－ＮＨＣＯ－、又は＊－ＮＨＣＯＯ－（＊は、酸素原子との結合位置を示す。）である。Ｒ^８は、炭素数１～２０の１価の有機基である。ｃは、０～４の整数である。ｄは、１～３の整数である。ｅは、１～１０の整数である。ｅが１の場合、Ｘは１価の有機基であり、ｅが２以上の場合、Ｘはｅ価の連結基である。Ｒ^６、Ｒ^７又はＲ^８が複数である場合、複数のＲ^６、複数のＲ^７又は複数のＲ^８は、同一でも異なっていてもよい。） The invention made to solve the above problems is a curable composition containing a first compound represented by the following formula (1), a second compound represented by the following formula (2), a binder containing a compound having a polymerizable group, and a solvent.

(In formula (1), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 30 carbon atoms. R ⁴ and R ⁵ are each independently a monovalent organic group having 1 to 30 carbon atoms or a halogen atom. a and b are each independently an integer of 0 to 3. When a is 2 or more, multiple R ^4s may be the same or different. When b is 2 or more, multiple R ^5s may be the same or different.)

(In formula (2), A is a ring structure composed of one or more five-membered or six-membered rings. R ⁶ is a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 40 carbon atoms. ^{R 7} is *-CO-, *-COO-, *-SCO-, *-COS-, *-S-COO-, *-CONH-, *-NHCO-, or *-NHCOO- (* indicates the bonding position with the oxygen atom). ^{R 8} is a monovalent organic group having 1 to 20 carbon atoms. c is an integer of 0 to 4. d is an integer of 1 to 3. e is an integer of 1 to 10. When e is 1, X is a monovalent organic group, and when e is 2 or more, X is an e-valent linking group. When there are multiple R ⁶ , R ⁷ , or R ⁸ , the multiple R ⁶ , multiple R ⁷ , or multiple R ⁸ may be the same or different.)

The present invention provides a curable composition that can be used to form an optical filter that has good ultraviolet ray shielding properties close to the visible light region, good visible light transmittance and heat resistance, and few defects such as foreign matter.

[Curable composition]
A curable composition according to one embodiment of the present invention contains (A) a first compound represented by formula (1) (hereinafter also referred to as "(A) compound"), (B) a second compound represented by formula (2) (hereinafter also referred to as "(B) compound"), (C) a binder, and (D) a solvent. The (C) binder contains a compound having a polymerizable group.

The curable composition has good ultraviolet shielding properties close to the visible light region, good visible light transmittance and good heat resistance, and can form an optical filter with few defects such as foreign matter. The product formed from the curable composition may be a cured product, a cured film, a shielding film, or the like. The reason why the curable composition produces the above-mentioned effect is unclear, but the following reasons are presumed. The (A) compound is an oxime-based polymerization initiator in which a nitro group is bonded to a carbazole skeleton. It is presumed that after the (A) compound functions as a polymerization initiator, a compound having a carbazole skeleton to which a nitro group is bonded tends to remain as a residue in the cured product (optical filter). This residue, by having a carbazole skeleton to which a nitro group is bonded, can sufficiently absorb ultraviolet rays close to the visible light region (for example, ultraviolet rays with a wavelength of 350 to 395 nm) while having sufficient transmittance to visible light in the cured product. On the other hand, the residue is likely to cause defects, and specifically, it is presumed that defects such as foreign matter occur due to the generation of radicals derived from the residue in the cured product. In contrast, the (B) compound has a structure in which the protective group (-R ⁷ -R ⁸ ) is eliminated at high temperatures, and the function of scavenging radicals is only expressed after the elimination. Therefore, the (B) compound does not capture radicals generated from the (A) compound, which is a polymerization initiator, during heating for curing, and can sufficiently capture radicals derived from residues generated in the cured product (optical filter) after curing. From this, it is presumed that the curable composition containing the (A) compound and the (B) compound can form an optical filter that has good ultraviolet shielding properties close to the visible light region and good visible light transmittance, and has few defects such as foreign matter. In addition, the heat resistance of the formed optical filter is also improved by using the (A) compound as a polymerization initiator.

[(A) Compound]
The compound (A) is a compound represented by the following formula (1): As described above, the compound (A) functions well as a polymerization initiator, while remaining in the obtained optical filter and absorbing ultraviolet light close to the visible light region.

In formula (1), R ¹ , R ² and R ³ are each independently a monovalent organic group having 1 to 30 carbon atoms. ^{R 4} and R ⁵ are each independently a monovalent organic group having 1 to 30 carbon atoms or a halogen atom. a and b are each independently an integer of 0 to 3. When a is 2 or more, multiple R ^4s may be the same or different. When b is 2 or more, multiple R ^5s may be the same or different.

Here, "organic group" refers to a group containing at least one carbon atom.

Examples of the monovalent organic group having 1 to 30 carbon atoms and represented by R ¹ to R ⁵ include monovalent hydrocarbon groups, groups containing a divalent heteroatom-containing group at the carbon-carbon bond or at the bond-side terminal of the hydrocarbon group, and groups in which some or all of the hydrogen atoms in the hydrocarbon group and the group containing the heteroatom-containing group have been substituted with monovalent heteroatom-containing groups.

Examples of monovalent hydrocarbon groups include linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups.

Examples of the chain hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group;
alkenyl groups such as ethenyl, propenyl, butenyl, and pentenyl;
Examples of the alkynyl group include an ethynyl group, a propynyl group, a butynyl group, and a pentynyl group.

Examples of the alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group;
Polycyclic cycloalkyl groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group, and a tetracyclododecyl group;
monocyclic cycloalkenyl groups such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, or a cyclohexenyl group;
Examples of the alkyl group include polycyclic cycloalkenyl groups such as norbornenyl and tricyclodecenyl.
The alicyclic hydrocarbon group may be a hydrocarbon group having a combination of a chain structure and an alicyclic structure, such as a cycloalkylalkyl group such as a 2-cyclopentylethyl group or a 2-cyclohexylethyl group.

Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group;
Examples of the aryl group include aralkyl groups such as a benzyl group, a phenethyl group, a naphthylmethyl group, and an anthrylmethyl group.

Examples of heteroatoms contained in the monovalent or divalent heteroatom-containing group include an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, and a phosphorus atom. Among these, an oxygen atom, a sulfur atom, and a nitrogen atom are preferred, and an oxygen atom is more preferred.

Examples of divalent heteroatom-containing groups include -O-, -CO-, -CS-, -NR'-, and combinations of these. R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of monovalent heteroatom-containing groups include hydroxyl groups, carboxyl groups, sulfanyl groups (-SH), amino groups, and cyano groups.

Examples of the halogen atom represented by R ⁴ and R ⁵ include a fluorine atom, a chlorine atom, and a bromine atom.

^R1 is preferably a substituted or unsubstituted hydrocarbon group, more preferably a substituted hydrocarbon group.As the above-mentioned hydrocarbon group, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group and an aryl group are preferred.When ^R1 is a substituted or unsubstituted aryl group, the obtained optical filter tends to have a higher ultraviolet shielding property close to the visible light region.On the other hand, when ^R1 is a substituted or unsubstituted alkyl group, a cycloalkyl group or a cycloalkylalkyl group, the obtained optical filter tends to have a higher visible light transmittance.

Examples of the substituent that the hydrocarbon group represented by ^R1 may have include alkoxy groups which may be substituted or unsubstituted. The alkoxy group refers to a group in which a hydrocarbon group is bonded to an oxygen atom. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a phenyloxy group. Examples of the substituent that the alkoxy group may have include an alkoxy group and a heterocyclic group. Examples of the heterocyclic group include 5- to 7-membered heterocycles such as a pyridyl group, a pyrimidyl group, a furyl group, a thienyl group, a tetrahydrofuryl group, a dioxolanyl group, a benzoxazol-2-yl group, a tetrahydropyranyl group, a pyrrolidyl group, an imidazolidyl group, a pyrazolidyl group, a thiazolidyl group, an isothiazolidyl group, an oxazolidyl group, an isoxazolidyl group, a piperidyl group, a piperazyl group, and a morpholinyl group. These heterocyclic groups may further have a substituent such as an alkyl group. The heterocyclic group is preferably a group composed of carbon atoms, hydrogen atoms, and oxygen atoms. The substituent that the hydrocarbon group represented by ^R1 may have is preferably a group composed of carbon atoms, hydrogen atoms, and oxygen atoms.

R ¹ is also preferably a hydrocarbon group or a group composed of carbon atoms, hydrogen atoms and oxygen atoms, more preferably a group composed of carbon atoms, hydrogen atoms and oxygen atoms. When R ¹ contains an oxygen atom, this oxygen atom is preferably an oxygen atom that forms an ether bond. In other words, R ¹ is preferably a hydrocarbon group or a group containing an oxygen atom between the carbon-carbon of the hydrocarbon group.

The upper limit of the carbon number of ^R1 is preferably 20, more preferably 15, and in some cases even more preferably 10. When the carbon number of ^R1 is equal to or less than the above upper limit, the visible light transmittance of the obtained optical filter tends to be increased. The lower limit of the carbon number of ^R1 may be preferably 3, 5, or 9. When the carbon number of ^R1 is equal to or more than the above lower limit, the blocking ability of the obtained optical filter for ultraviolet rays close to the visible light region tends to be increased.

^R2 is preferably a hydrocarbon group, more preferably an alkyl group or an aryl group, and even more preferably an alkyl group. The upper limit of the carbon number of ^R2 is preferably 10, more preferably 6, and even more preferably 3. ^R2 is particularly preferably a methyl group or an ethyl group, and most preferably a methyl group.

^R3 is preferably a hydrocarbon group, more preferably an alkyl group. The upper limit of the carbon number of ^R3 is preferably 10, more preferably 6, and still more preferably 3. ^R3 is particularly preferably a methyl group, an ethyl group, or a propyl group, and most preferably an ethyl group.

R ⁴ and R ⁵ are each preferably a hydrocarbon group, more preferably an alkyl group. The upper limit of the carbon number of R ⁴ and R ⁵ is preferably 10, more preferably 6, and further preferably 3, respectively.

a is preferably 0. b is preferably 0.

In the compound (A), the nitro group (—NO ₂ ) is preferably bonded to the 3-position of the carbazole skeleton.

Specific examples of the (A) compound include the compounds described in paragraph [0037] of International Publication No. 2017/010575. The (A) compound may be used alone or in combination of two or more.

The lower limit of the content of the (A) compound in the total solid content (components other than the (D) solvent) in the curable composition is preferably 0.1% by mass, and more preferably 0.3% by mass. When the content of the (A) compound is equal to or greater than the above lower limit, the resulting optical filter is more effective at blocking ultraviolet rays close to the visible light range, and also exhibits good curability, heat resistance, and the like. On the other hand, the upper limit of this content is preferably 30% by mass, more preferably 10% by mass, and in some cases even more preferably 5% by mass or 2% by mass. When the content of the (A) compound is equal to or less than the above upper limit, defects such as foreign matter in the resulting optical filter are further reduced, and the visible light transmittance is also improved.

[Compound (A')]
The curable composition may further contain a compound (A') which is a polymerization initiator other than the compound (A). As the compound (A'), a conventionally known polymerization initiator can be used. As the compound (A'), for example, O-acyloxime compounds other than the compound (A), thioxanthone compounds, acetophenone compounds, biimidazole compounds, triazine compounds, onium salt compounds, benzoin compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, diazo compounds, imide sulfonate compounds, onium salt compounds, etc. can be mentioned. Among these, O-acyloxime compounds are preferred.

As the (A') compound, a compound having a phenylthio skeleton and an oxime ester structure is more preferable. By using such a compound in combination with the (A') compound, the visible light transmittance of the obtained optical filter tends to be improved.

As a compound having a phenylthio skeleton and an oxime ester structure, a compound represented by the following formula (5) is preferred.

In formula (5), R ⁹ and R ¹⁰ are each independently a monovalent organic group having 1 to 30 carbon atoms. ^{R 11} is a hydrogen atom, a benzoyl group, a hydroxy group, a carboxy group, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. R ¹² and R ¹³ are each independently a monovalent organic group having 1 to 30 carbon atoms or a halogen atom. f and g are each independently an integer of 0 to 4. When f is 2 or more, multiple R ¹² may be the same or different. When g is 2 or more, multiple R ¹³ may be the same or different.

The monovalent organic groups having 1 to 30 carbon atoms represented by R ⁹ , R ¹⁰ , R ¹² and R ¹³ are the same as the monovalent organic groups having 1 to 30 carbon atoms represented by R ¹ and the like.

^R9 is preferably a substituted or unsubstituted hydrocarbon group, more preferably an unsubstituted hydrocarbon group. The hydrocarbon group is preferably an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, or an aryl group, more preferably an alkyl group. Examples of the substituent that may be possessed by the hydrocarbon group represented by ^R9 include the same groups as the substituent that may be possessed by the hydrocarbon group represented by ^R1 .

The upper limit of the number of carbon atoms in R ⁹ is preferably 20, more preferably 10, and still more preferably 6. The lower limit of the number of carbon atoms in R ⁹ is 1.

R ¹⁰ is preferably a hydrocarbon group, more preferably an alkyl group or an aryl group. The upper limit of the carbon number of R ¹⁰ is preferably 10, more preferably 6. R ¹⁰ is particularly preferably a methyl group, an ethyl group, a propyl group or a phenyl group.

Examples of the substituent that the alkoxy group represented by R ¹¹ may have include a hydroxy group, a carboxy group, an alkoxy group, etc., and the hydroxy group is preferred.

R ¹¹ is preferably a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, and more preferably a hydrogen atom or a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. Among the substituted or unsubstituted alkoxy groups having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms and having a hydroxy group as a substituent is preferred, and an alkoxy group having 1 to 4 carbon atoms and having a hydroxy group as a substituent is more preferred.

R ¹² and R ¹³ are each preferably a hydrocarbon group, more preferably an alkyl group. The upper limit of the carbon number of R ¹² and R ¹³ is preferably 10, more preferably 6, and further preferably 3, respectively.

g is preferably 0. f is preferably 0.

The (A') compound may be used alone or in a mixture of two or more.

When the curable composition contains the (A') compound, the lower limit of the content of the (A') compound in the total solid content of the curable composition is preferably 1 mass %, more preferably 2 mass %. On the other hand, the upper limit of this content is preferably 20 mass %, more preferably 10 mass %.

The lower limit of the total content of the (A) compound and the (A') compound in the total solid content of the curable composition is preferably 1% by mass, and more preferably 3% by mass. When the total content is equal to or greater than the lower limit, the resulting optical filter is more effective at blocking ultraviolet rays close to the visible light range, and the heat resistance can also be improved. On the other hand, the upper limit of this content is preferably 30% by mass, and more preferably 10% by mass. When the total content is equal to or less than the upper limit, defects such as foreign matter in the resulting optical filter are further reduced, and the visible light transmittance is also improved.

When the curable composition uses the compound (A) in combination with a compound having a phenylthio skeleton and an oxime ester structure, the content ratio (mass ratio) of these is preferably 1:20 to 20:1, and more preferably 1:15 to 15:1. By using the compound (A) in combination with a compound having a phenylthio skeleton and an oxime ester structure in such a ratio, the shielding ability of ultraviolet rays close to the visible light region, the visible light transmittance, etc. of the obtained optical filter are further improved.

[(B) Compound]
The compound (B) is a compound represented by the following formula (2). As described above, the compound (B) is a latent radical scavenger that exhibits radical scavenging ability only after heating. By containing the compound (B) in the curable composition, defects in the obtained optical filter are reduced, and as a result, good visible light transmittance is exhibited.

In formula (2), A is a ring structure composed of one or more five-membered or six-membered rings. R ⁶ is a halogen atom, a hydroxyl group, a nitro group, or a monovalent organic group having 1 to 40 carbon atoms. ^{R 7} is *-CO-, *-COO-, *-SCO-, *-COS-, *-S-COO-, *-CONH-, *-NHCO-, or *-NHCOO- (* indicates the bonding position with the oxygen atom). ^{R 8} is a monovalent organic group having 1 to 20 carbon atoms. c is an integer of 0 to 4. d is an integer of 1 to 3. e is an integer of 1 to 10. When e is 1, X is a monovalent organic group, and when e is 2 or more, X is an e-valent linking group. When there are a plurality of R ⁶ , R ⁷ or R ⁸ , the plurality of R ⁶ , R ⁷ or R ⁸ may be the same or different.

Examples of the ring structure represented by A include carbocyclic rings and heterocyclic rings. Examples of the carbocyclic rings include alicyclic rings such as a cyclopentane ring, a cyclohexane ring, a cyclopentene ring, and a cyclohexene ring, and aromatic rings such as a benzene ring and a naphthalene ring. Examples of the heterocyclic rings include a furan ring, a thiophene ring, a pyrrole ring, a pyrrolidine ring, a pyrazolidine ring, a pyrazole ring, an imidazole ring, an imidazolidine ring, an oxazole ring, an isoxazole ring, an isoxazolidine ring, a thiazole ring, an isothiazole ring, an isothiazolidine ring, a piperidine ring, a piperazine ring, a morpholine ring, a thiomorpholine ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring. The heterocyclic ring may be an aromatic ring or a non-aromatic ring.

The number of carbon atoms in the ring structure represented by A is preferably 5 or more and 12 or less, more preferably 5 or 6, and even more preferably 6. The ring structure represented by A is preferably a carbon ring, and more preferably a benzene ring.

Examples of the monovalent organic group having 1 to 40 carbon atoms represented by ^R6 include those exemplified as the monovalent organic group having 1 to 30 carbon atoms represented by R1, ^etc.

^R6 is preferably a hydrocarbon group, more preferably an alkyl group, and further preferably a tertiary alkyl group such as a t-butyl group. The upper limit of the number of carbon atoms in ^R6 is preferably 10, more preferably 6. The lower limit of the number of carbon atoms in ^R6 is preferably 2, more preferably 4.

R ⁷ is preferably *-COO-, *-COS-, or *-CONH-, and more preferably *-COO-. When R ⁷ is such a linking group, dissociation accompanying heating during curing occurs more effectively, and defects in the obtained optical filter are more sufficiently reduced.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by ^R8 include those having 1 to 20 carbon atoms among those exemplified as the monovalent organic group having 1 to 30 carbon atoms represented by ^R1, etc.

R ⁸ is preferably a hydrocarbon group, more preferably an alkyl group, and even more preferably a tertiary alkyl group such as a t-butyl group. The upper limit of the number of carbon atoms in R ⁸ is preferably 16, more preferably 8, and even more preferably 2. When ^{R 8} is such a group, defects in the obtained optical filter tend to be more sufficiently reduced.

c is preferably 2 or more, and more preferably 2.

d is preferably 1.

The lower limit of e is preferably 2, more preferably 3, and even more preferably 4. When e is equal to or greater than the above lower limit, defects in the resulting optical filter tend to be more sufficiently reduced. The upper limit of e may be 8, 6, or 4.

When c is 2 and d is 1, it is preferred that a group represented by ^R6 is bonded to each of the atoms on both sides of the atom of the ring structure A to which the group represented by -O-R ⁷ -R ⁸ is bonded. Specific examples of such compounds (B) include compounds represented by the following formula (6).

In formula (6), R ⁶ to R ⁸ , X and e have the same meanings as R ⁶ to R ⁸ , X and e in formula (2).

Examples of the monovalent organic group represented by X when e is 1 include those exemplified as the monovalent organic group having 1 to 30 carbon atoms represented by R1, ^etc.

When e is 2 or more, examples of the e-valent linking group represented by X include e-valent organic groups, as well as -O- and -NR'- (R' is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms). Examples of the e-valent organic group include groups in which (e-1) hydrogen atoms have been further removed from the above-mentioned monovalent organic groups.

X is preferably an e-valent organic group. This organic group is preferably a hydrocarbon group, or a group containing -O-, -CO- or -COO- between the carbon atoms of the hydrocarbon group, and more preferably a hydrocarbon group, or a group containing -COO- between the carbon atoms of the hydrocarbon group. The organic group represented by X may contain multiple types of -O-, -CO- and -COO-, or may contain multiple -O-, multiple -CO- or multiple -COO-.

The upper limit of the carbon number of X is preferably 40, more preferably 30, and even more preferably 24. The lower limit of this carbon number is preferably 1, more preferably 4, more preferably 8, and even more preferably 12.

When A is a benzene ring, X is preferably bonded at the para position to the group represented by --O-- ^R.sup.7 -- ^R.sup.8 .

Specific examples of the (B) compound include the compounds described in paragraphs [0061] to [0082] of WO 2014/021023. The (B) compound can be used alone or in a mixture of two or more. The (B) compound can be obtained, for example, by reacting a phenolic compound with an acid anhydride, an acid chloride, a Boc reagent, an alkyl halide compound, a silyl chloride compound, an allyl ether compound, or the like.

The lower limit of the content of the (B) compound in the total solid content of the curable composition is preferably 0.1% by mass, more preferably 0.2% by mass, and even more preferably 0.3% by mass. When the content of the (B) compound is equal to or greater than the above lower limit, sufficient radical scavenging ability is exhibited in the obtained optical filter, and defects can be further reduced. On the other hand, the upper limit of this content is preferably 10% by mass, more preferably 5% by mass, and even more preferably 2% by mass.

[(B') Compound]
The curable composition preferably further comprises a compound (B') which is an antioxidant that is not protected by a protective group. The curable composition further comprises a compound (B'), which can sufficiently capture radicals that may be generated in the curable composition before curing, thereby improving storage stability and reducing defects in the optical filter obtained by using the curable composition after long-term storage, for example.

Examples of the (B') compound include conventionally known antioxidants such as 2,2-thiobis(4-methyl-6-t-butylphenol), 2,6-di-t-butylphenol, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3,9-bis[2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxa-spiro[5.5]undecane, and thiodiethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].

As the (B') compound, a compound represented by the following formula (4) is preferred.

In formula (4), A' is a ring structure composed of one or more five-membered or six-membered rings. R ⁶ ' is a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 40 carbon atoms. c' is an integer from 0 to 4. d' is an integer from 1 to 3. e' is an integer from 1 to 10. When e' is 1, X' is a monovalent organic group, and when e' is 2 or more, X' is an e'-valent linking group. When there are multiple R ⁶ 's, the multiple R ⁶ 's may be the same or different.

Examples of ring structures represented by A' and consisting of one or more five- or six-membered rings include those exemplified as ring structures represented by A and consisting of one or more five- or six-membered rings.

The number of carbon atoms in the ring structure represented by A' is preferably 5 or more and 12 or less, more preferably 5 or 6, and even more preferably 6. The ring structure represented by A' is preferably a carbon ring, and more preferably a benzene ring.

Examples of the monovalent organic group having 1 to 40 carbon atoms represented by R ⁶ ' include those exemplified as the monovalent organic group having 1 to 30 carbon atoms represented by R ¹ and the like.

R ⁶ ' is preferably a hydrocarbon group, more preferably an alkyl group, and further preferably a tertiary alkyl group such as a t-butyl group. The upper limit of the number of carbon atoms of R ⁶ ' is preferably 10, more preferably 6. The lower limit of the number of carbon atoms of R ⁶ ' is preferably 2, more preferably 4.

c' is preferably 2 or more, and more preferably 2.

d' is preferably 1.

The lower limit of e' is preferably 2, more preferably 3, and even more preferably 4. When e' is equal to or greater than the above lower limit, defects in the resulting optical filter tend to be more sufficiently reduced. The upper limit of e' may be 8, 6, or 4.

When c' is 2 and d' is 1, it is preferred that a group represented by R ⁶ ' is bonded to each of the atoms on both sides of the atom in the ring structure (A') to which the hydroxy group (-OH) is bonded.

Examples of the monovalent organic group represented by X' and the e'-valent linking group include those exemplified as the monovalent organic group represented by X and the e-valent linking group.

X' is preferably an organic group with a valence of e'. This organic group is preferably a hydrocarbon group, or a group containing -O-, -CO- or -COO- between the carbon atoms of the hydrocarbon group, and more preferably a hydrocarbon group, or a group containing -COO- between the carbon atoms of the hydrocarbon group. The organic group represented by X' may contain multiple types of -O-, -CO- and -COO-, or may contain multiple -O-, multiple -CO- or multiple -COO-.

The upper limit of the carbon number of X' is preferably 40, more preferably 30, and even more preferably 24. The lower limit of this carbon number is preferably 1, more preferably 4, more preferably 8, and even more preferably 12.

When A' is a benzene ring, X' is preferably bonded in the para position to the hydroxyl group (-OH).

The (B') compound may be used alone or in a mixture of two or more.

When the curable composition contains the (B') compound, the lower limit of the content of the (B') compound in the total solid content of the curable composition is preferably 0.1 mass%, more preferably 0.2 mass%, and even more preferably 0.3 mass%. When the content of the (B') compound is equal to or greater than the above lower limit, storage stability is sufficiently improved and defects can be further reduced. On the other hand, the upper limit of this content is preferably 5 mass%, and more preferably 2 mass%.

The lower limit of the total content of the (B) compound and the (B') compound in the total solid content of the curable composition is preferably 0.1 mass%, more preferably 0.3 mass%, and even more preferably 0.5 mass%. When the total content is equal to or greater than the lower limit, defects in the resulting optical filter can be further reduced. On the other hand, the upper limit of this content is preferably 10 mass%, more preferably 5 mass%, and even more preferably 2 mass%. When the total content is equal to or less than the upper limit, visible light transmittance and the like tend to be improved.

When the (B) compound and the (B') compound are used in combination in the curable composition, the content ratio (mass ratio) of these is preferably 1:9 to 9:1, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4. By using the (B) compound and the (B') compound in combination in such a ratio, undesirable radicals that may be generated before and after curing can be effectively captured, and defects in the obtained optical filter are further reduced.

[(C) Binder]
The binder (C) is usually a component that becomes a base material in the resulting cured product such as an optical filter, a shielding film, etc. The binder (C) may be used alone or in combination of two or more kinds.

The binder (C) contains a compound having a polymerizable group. By containing a compound having a polymerizable group, the curable composition can exhibit good curability and good heat resistance of the obtained optical filter. The compound having a polymerizable group may have one or more polymerizable groups, but is preferably a compound having two or more polymerizable groups. Examples of the polymerizable group include a (meth)acryloyl group, a vinyl group, an oxiranyl group, an oxetanyl group, an N-alkoxymethylamino group, and an alkoxysilyl group. The compound having a polymerizable group may be a monomer (non-polymer) or a polymer.

[(C-1) Polymerizable compound]
The binder (C) preferably contains a polymerizable compound (C-1) which is a monomer as a compound having a polymerizable group. The polymerizable compound (C-1) is preferably a compound having two or more (meth)alkyl groups. (C-1) A compound having an acryloyl group and a compound having two or more N-alkoxymethylamino groups are preferred, and a compound having two or more (meth)acryloyl groups is more preferred. They can be used alone or in combination of two or more.

Examples of compounds having two or more (meth)acryloyl groups include polyfunctional (meth)acrylates, which are reaction products between aliphatic polyhydroxy compounds and (meth)acrylic acid, caprolactone-modified polyfunctional (meth)acrylates, alkylene oxide-modified polyfunctional (meth)acrylates, polyfunctional urethane (meth)acrylates, which are reaction products between hydroxyl-containing (meth)acrylates and polyfunctional isocyanates, and polyfunctional (meth)acrylates having carboxyl groups, which are reaction products between hydroxyl-containing (meth)acrylates and acid anhydrides.

Here, examples of the aliphatic polyhydroxy compounds include divalent aliphatic polyhydroxy compounds such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol, and trivalent or higher aliphatic polyhydroxy compounds such as glycerin, trimethylolpropane, pentaerythritol, and dipentaerythritol. Examples of the (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and glycerol dimethacrylate. Examples of the polyfunctional isocyanates include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, and isophorone diisocyanate. Examples of the acid anhydride include dibasic acid anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, itaconic anhydride, phthalic anhydride, and hexahydrophthalic anhydride, and tetrabasic acid dianhydrides such as pyromellitic anhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride.

Specific examples of compounds having two or more (meth)acryloyl groups include, for example, ω-carboxypolycaprolactone mono(meth)acrylate, ethylene glycol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, bisphenoxyethanol fluorene di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxy Examples of such compounds include propyl methacrylate, 2-(2'-vinyloxyethoxy)ethyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tri(2-(meth)acryloyloxyethyl)phosphate, ethylene oxide modified dipentaerythritol hexaacrylate, succinic acid modified pentaerythritol triacrylate, and urethane (meth)acrylate compounds.

Among compounds having two or more (meth)acryloyl groups, polyfunctional (meth)acrylates are preferred, and polyfunctional (meth)acrylates having 3 to 10 (meth)acryloyl groups are more preferred. Specifically, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate are preferred.

Examples of compounds having two or more N-alkoxymethylamino groups include compounds having a melamine structure, a benzoguanamine structure, and a urea structure. Specific examples of compounds having two or more N-alkoxymethylamino groups include N,N,N',N',N'',N''-hexa(alkoxymethyl)melamine, N,N,N',N'-tetra(alkoxymethyl)benzoguanamine, and N,N,N',N'-tetra(alkoxymethyl)glycoluril.

The lower limit of the content of the polymerizable compound (C-1) in the total solid content of the curable composition is preferably 5% by mass, more preferably 10% by mass, and even more preferably 20% by mass. On the other hand, the upper limit of this content is preferably 60% by mass, more preferably 50% by mass, and even more preferably 40%.

[(C-2) Polymer]
The binder (C) preferably contains a polymer (C-2). A part or all of the polymer (C-2) may be a polymer used as a dispersant. C-2) The polymer preferably has a polymerizable group in order to improve strength, sensitivity, heat resistance, etc., and more preferably has a structural unit containing a polymerizable group. is preferably a (meth)acryloyl group, an oxiranyl group, an oxetanyl group, an alkoxysilyl group, or a combination thereof, and more preferably a (meth)acryloyl group.

Examples of monomers that provide structural units containing a polymerizable group include glycidyl (meth)acrylate, 3-(meth)acryloyloxymethyl-3-ethyloxetane, 3,4-epoxycyclohexylmethyl (meth)acrylate, 2,3-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxytricyclo[5.2.1.0 ^2.6 ]decyl (meth)acrylate, and 3-methacryloxypropyltriethoxysilane.

For example, a structural unit containing a polymerizable group can also be introduced by reacting a resin having a structural unit containing a carboxy group with a compound having a group that reacts with the carboxy group (such as an oxiranyl group or an oxetanyl group) and a polymerizable group such as a (meth)acryloyl group.

The lower limit of the content of structural units having a polymerizable group in the (C-2) polymer is preferably 5% by mass, more preferably 10% by mass, even more preferably 15% by mass, and even more preferably 30% by mass, 50% by mass, or 75% by mass, relative to 100% by mass of the (C-2) polymer. On the other hand, the upper limit of this content is preferably 95% by mass, more preferably 90% by mass, and even more preferably 85% by mass.

The polymer (C-2) preferably has a ring structure in the main chain to improve heat resistance. The number of ring members in this ring structure may be, for example, 3 to 12, but 5 to 8 is preferred.

Examples of monomers that provide structural units containing a ring structure in the main chain include N-substituted maleimide monomers and cycloolefins.

An N-substituted maleimide monomer is a compound in which the hydrogen atom bonded to the nitrogen atom in maleimide is replaced with a substituent. The substituent is preferably a hydrocarbon group, more preferably a hydrocarbon group having a ring structure, and more preferably an aromatic hydrocarbon group. Examples of N-substituted maleimide monomers include N-phenylmaleimide, N-naphthylmaleimide, N-cyclohexylmaleimide, N-cyclooctylmaleimide, and N-methylmaleimide.

Examples of cycloolefins include norbornene-based olefins, tetracyclododecene-based olefins, and dicyclopentadiene-based olefins.

Other examples of the polymer (C-2) that has a ring structure in the main chain include phenolic resins.

The content of structural units containing a ring structure in the main chain in the (C-2) polymer is preferably 1% by mass to 50% by mass, and more preferably 5% by mass to 30% by mass, relative to 100% by mass of the (C-2) polymer.

The (C-2) polymer preferably has an acidic group. Examples of the acidic group include a carboxy group, an acid anhydride group, a phenolic hydroxyl group, and a sulfo group. Among the above, the acidic group is preferably a carboxy group. The (C-2) polymer is preferably a resin containing a structural unit having one or more acidic groups. When the (C-2) polymer has an acidic group, it can exhibit good alkali solubility. When the (C-2) polymer is alkali soluble, it can be developed in an alkali and an optical filter having a desired pattern shape can be formed.

Examples of monomers that provide structural units containing an acidic group include monomers having a carboxy group, such as unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, α-chloroacrylic acid, and cinnamic acid; unsaturated dicarboxylic acids or anhydrides thereof such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, and mesaconic acid; mono[(meth)acryloyloxyalkyl] esters of divalent or higher polyvalent carboxylic acids such as mono[2-(meth)acryloyloxyethyl] succinate and mono[2-(meth)acryloyloxyethyl] phthalate; and mono(meth)acrylates of polymers having a carboxy group and a hydroxyl group at both ends, such as ω-carboxypolycaprolactone mono(meth)acrylate.

Examples of monomers having a phenolic hydroxyl group include 4-vinylphenol, 4-isopropenylphenol, and 4-hydroxyphenyl (meth)acrylate.

The content of the structural unit containing an acidic group in the (C-2) polymer is preferably 1% by mass to 50% by mass, and more preferably 3% by mass to 30% by mass, based on 100% by mass of the (C-2) polymer.

The polymer (C-2) may further contain other structural units. Examples of monomers which provide other structural units include aromatic vinyl compounds such as styrene, α-methylstyrene, p-hydroxystyrene, p-hydroxy-α-methylstyrene, p-vinylbenzyl glycidyl ether, and acenaphthylene;
Methyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, allyl (meth)acrylate, benzyl (meth)acrylate, polyethylene glycol (degree of polymerization 2-10) methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization 2-10) methyl ether (meth)acrylate, polyethylene glycol (degree of polymerization 2-10) mono(meth)acrylate, polypropylene glycol (degree of polymerization 2-10) mono(meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclo[5.2.1.0 ^2,6 ] (meth)acrylic acid esters such as decan-8-yl (meth)acrylate, dicyclopentenyl (meth)acrylate, glycerol mono(meth)acrylate, 4-hydroxyphenyl (meth)acrylate, ethylene oxide-modified (meth)acrylate of para-cumylphenol, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3-[(meth)acryloyloxymethyl]oxetane, and 3-[(meth)acryloyloxymethyl]-3-ethyloxetane;
Vinyl ethers such as cyclohexyl vinyl ether, isobornyl vinyl ether, tricyclo[5.2.1.0 ^2,6 ]decan-8-yl vinyl ether, pentacyclopentadecanyl vinyl ether, and 3-(vinyloxymethyl)-3-ethyloxetane;
Examples of the polymer include macromonomers having a mono(meth)acryloyl group at the end of the polymer molecular chain, such as polystyrene, polymethyl(meth)acrylate, poly-n-butyl(meth)acrylate, and polysiloxane.

The (C-2) polymer can be obtained by polymerizing the above-mentioned monomers by a known method. The (C-2) polymer may be used alone or in combination of two or more types.

The polystyrene-equivalent weight average molecular weight (Mw) of the polymer (C-2) is preferably 2,000 to 500,000, more preferably 3,000 to 100,000, and even more preferably 4,000 to 30,000, as measured by gel permeation chromatography (GPC). When the Mw is within the above range, the polymer (C-2) has excellent solubility in solvents and developers and sufficient mechanical properties.

The lower limit of the content of the (C-2) polymer in the total solid content of the curable composition is preferably 10% by mass, more preferably 20% by mass, and even more preferably 30% by mass. On the other hand, the upper limit of this content is preferably 60% by mass, more preferably 50% by mass, and even more preferably 45% by mass. By setting the content of the (C-2) polymer within the above range, the properties of the obtained optical filter regarding ultraviolet shielding, visible light transmittance, heat resistance, etc. can be more fully exhibited.

The lower limit of the content of the binder (C) in the total solid content of the curable composition is preferably 30% by mass, more preferably 40% by mass, and even more preferably 50% by mass. On the other hand, the upper limit of this content is preferably 90% by mass, and more preferably 80% by mass. By setting the content of the binder (C) within the above range, the properties of the obtained optical filter regarding ultraviolet shielding, visible light transmittance, heat resistance, etc. can be more fully exhibited.

The average polymerizable double bond equivalent of the binder (C) in the curable composition is preferably 600 or less, more preferably 400 or less, and even more preferably 200 or less. Here, the average polymerizable double bond equivalent is an index showing how many polymerizable double bond groups, such as (meth)acryloyl groups and alkenyl groups, that can react with radicals generated from the component (A) are present in the binder (C). By setting the average polymerizable double bond equivalent within the above range, the solvent durability of the obtained optical filter is more fully exhibited. The lower limit of the average polymerizable double bond equivalent is, for example, 30, and may be 50 or 80.

The average polymerizable double bond equivalent is the mass (g) of the binder (C) per 1 mol of polymerizable double bonds contained in the binder (C), and is calculated by the following formula.
Average polymerizable double bond equivalent (g/mol)
= (C) total mass of binder (g) / (C) amount of all polymerizable double bonds contained in binder (mol)
In other words, the average polymerizable double bond equivalent of the binder (C) is the molecular weight of the binder (C) per one polymerizable double bond contained in the binder (C).

[(D) Solvent]
The (D) solvent is a component that dissolves or disperses the other components. As the (D) solvent, any solvent that disperses or dissolves the other components, does not react with these components, and has appropriate volatility can be appropriately selected and used. One or more (D) solvents can be used.

(D) Examples of solvents include (poly)alkylene glycol monoalkyl ethers, alkyl lactate esters, (cyclo)alkyl alcohols, keto alcohols, (poly)alkylene glycol monoalkyl ether acetates, ethers, ketones, diacetates, alkoxycarboxylic acid esters, esters, aromatic hydrocarbons, amides, and lactams.

(D) The solvent preferably contains a compound having a cyclic structure. By using a compound having a cyclic structure as a solvent, the solubility and dispersibility are improved. The cyclic structure may be a carbon ring or a heterocycle. The cyclic structure may be a polycycle or a monocycle. The cyclic structure may be an aromatic ring or an aliphatic ring.

Preferred solvents that are compounds having a cyclic structure include cyclic ketones, cyclic ethers, lactones (γ-butyrolactone, ε-caprolactone, etc.), lactams, aromatic hydrocarbons (toluene, etc.), and combinations thereof. Among these, preferred are cyclic ketones, lactones, and aromatic hydrocarbons, more preferred are cyclic ketones and lactones, and even more preferred are cyclic ketones.

Examples of cyclic ketones include cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, and cyclooctanone. Among these, cyclopentanone, cyclohexanone, and cycloheptanone are preferred, and cyclopentanone and cyclohexanone are more preferred.

Examples of cyclic ethers include tetrahydrofuran and tetrahydropyran.

Examples of lactones include γ-butyrolactone and ε-caprolactone, with γ-butyrolactone being preferred.

Examples of lactams include pentano-4-lactam, 5-methyl-2-pyrrolidinone, hexano-6-lactam, and 6-hexanelactam.

The lower limit of the content of the compound having a cyclic structure in the (D) solvent is preferably 30% by mass, more preferably 50% by mass, even more preferably 70% by mass, and even more preferably 75% by mass. The (D) solvent may be substantially composed of only the compound having a cyclic structure. By setting the content of the compound having a cyclic structure in the (D) solvent to the above lower limit or more, the dispersibility and solubility of other components are increased, and the effects of the present invention are more fully achieved.

The lower limit of the solids concentration in the curable composition (total concentration of each component excluding the (D) solvent) is preferably 5% by mass, more preferably 10% by mass, and even more preferably 20% by mass. On the other hand, the upper limit of this solids concentration is preferably 60% by mass, more preferably 50% by mass, and even more preferably 40% by mass. By setting the solids concentration in the above range, dispersibility, storage stability, coatability, etc. are improved.

[(E) Dye]
The curable composition preferably contains a dye having a maximum absorption wavelength in the wavelength region of 650 nm or more and 2,000 nm or less. When the curable composition further contains such a dye (E), the obtained optical filter can exhibit infrared shielding properties close to the visible light region. That is, when the curable composition further contains the dye (E), the obtained optical filter can effectively block ultraviolet and infrared rays close to the visible light region, and is suitable as an optical filter for a solid-state imaging device. The dye (E) may be a dye or a pigment. The dye (E) may be an organic or inorganic substance. One or more types of dye (E) can be used.

The (E) dye preferably contains at least one of a first dye (hereinafter also referred to as "(E-1) dye") having a maximum absorption wavelength in the wavelength region of 650 nm or more and 900 nm or less, and a second dye (hereinafter also referred to as "(E-2) dye") having a maximum absorption wavelength in the wavelength region of more than 900 nm and 2,000 nm or less, and more preferably contains both. By using such dyes, the ability to block infrared rays close to the visible light region is further improved, making the resulting optical filter more useful in applications such as solid-state imaging devices.

[(E-1) Dye]
The dye (E-1) preferably contains a phthalocyanine dye, a cyanine dye, a pyrrolopyrrole dye, a naphthalocyanine dye, a diimonium dye, an azo dye, a squarylium dye, or a combination thereof, and more preferably contains a phthalocyanine dye. It is also preferable to use two or more types of dye (E-1) in combination. These dyes can be conventionally known.

The lower limit of the maximum absorption wavelength of the (E-1) dye is preferably 680 nm, more preferably 700 nm, and even more preferably 720 nm. On the other hand, the upper limit of this maximum absorption wavelength is preferably 1,000 nm, more preferably 900 nm, more preferably 800 nm, and even more preferably 750 nm.

The (E-1) dye preferably contains a compound represented by the following formula (3), which is a phthalocyanine dye. This phthalocyanine compound has high transmittance in the visible light region (e.g., a wavelength region of 430 nm or more and 580 nm or less), while having high shielding properties in the near-infrared region (e.g., a wavelength region of 700 nm or more and 800 nm or less). In addition, this phthalocyanine compound has excellent compatibility with other components. Therefore, when the curable composition contains such a phthalocyanine compound, an optical filter can be formed that has fewer defects such as foreign matter and has better properties regarding visible light transmittance and infrared shielding properties.

In formula (3), each of the multiple R ^a's is independently a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Each of the multiple R ^b's is independently a hydrogen atom, a halogen atom, or an alkyl group. Each of the multiple R ^b's may be bonded to each other to form an aromatic ring together with the carbon chain to which they are bonded. M is two hydrogen atoms, a divalent metal atom, or a derivative of a trivalent or tetravalent metal atom. Each of the multiple n's is independently an integer of 3 to 6.

Examples of the alkyl group represented by R ^a include linear or branched alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group. The upper limit of the number of carbon atoms in this alkyl group is preferably 12, more preferably 8, and even more preferably 4.

Examples of the aryl group represented by R ^a include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, an anthracenyl group, etc. As the aryl group, a group constituted only of an aromatic ring is preferable, and a phenyl group or a naphthyl group is more preferable.

From the standpoint of the heat resistance of the resulting optical filter, R ^a is preferably a substituted or unsubstituted aryl group.

The alkyl group and aryl group represented by each of the multiple R ^a may or may not have a substituent, but preferably have a substituent. That is, each of the multiple R ^a is preferably an alkyl group having a substituent or an aryl group having a substituent. In this way, by having multiple R ^a with a substituent, the compatibility of the phthalocyanine compound is further improved, the defects such as foreign matter of the obtained optical filter are further suppressed, and the properties related to visible light transmittance and infrared shielding are also improved. Furthermore, by having multiple R ^a with a substituent, the heat resistance of the obtained optical filter is also improved.

The substituent that the alkyl group and aryl group represented by each of the multiple R ^a can have may be a hydrocarbon group such as an alkenyl group or an alkynyl group, but is preferably a group having a heteroatom. The heteroatom refers to an atom other than a hydrogen atom and a carbon atom. The alkyl group and aryl group represented by each of the multiple R ^a have a substituent having a heteroatom, so that the compatibility and the like are further improved, defects such as foreign matter in the obtained optical filter are further suppressed, and the properties related to visible light transmittance and infrared shielding are also improved. Furthermore, the multiple R ^a have a substituent having a heteroatom, so that the heat resistance of the obtained optical filter is also improved. As the heteroatom, a halogen atom, an oxygen atom, and a sulfur atom are preferable, and a halogen atom and an oxygen atom are more preferable.

Examples of substituents having a heteroatom include a halogen atom, an alkoxy group, an alkylthio group, a cyano group, a nitro group, a carboxy group, a hydroxy group, a thiol group, and an amino group.

As the halogen atom, a fluorine atom is preferred. As the alkoxy group, a methoxy group and an ethoxy group are preferred, and a methoxy group is more preferred.

Examples of the alkylthio group include a methylthio group (CH ₃ --S--), an ethylthio group (C ₂ H ₅ --S--), and a propylthio group (C ₃ H ₇ --S--), with the methylthio group and the ethylthio group being more preferred.

Among the substituents having heteroatoms, halogen atoms, alkoxy groups, and alkylthio groups are preferred, and halogen atoms and alkoxy groups are more preferred. Also preferred are halogen atoms, methoxy groups, ethoxy groups, methylthio groups, ethylthio groups, or combinations thereof. The number of carbon atoms in the substituents having heteroatoms may be 0 to 10, and preferably 1 to 4.

A plurality of R ^a may be the same or different, but is preferably the same.

A plurality of ^Rb may be bonded to each other. Usually, among a plurality of ^Rb , two ^Rb bonded to the same benzene ring are bonded to each other to form an aromatic ring together with the carbon chain to which they are bonded. Examples of the aromatic ring formed include a benzene ring, a naphthalene ring, and an anthracene ring. The hydrogen atoms of these aromatic rings may be substituted with a hydrocarbon group or other substituents.

R ^b is preferably a hydrogen atom. In addition, multiple R ^b may be the same or different, but are preferably the same.

Examples of divalent metal atoms represented by M include Pd, Cu, Zn, Pt, Ni, Co, Fe, Mn, Sn, In, Ru, Rh, and Pb. A divalent metal atom is a metal atom that can become a divalent cation.

Here, the derivative of a metal atom refers to an atomic group containing a metal atom. A trivalent metal atom refers to a metal atom that can become a trivalent cation. Examples of trivalent metal atoms include Al and In. A tetravalent metal atom refers to a metal atom that can become a tetravalent cation. Examples of tetravalent metal atoms include Si, Ge, and Sn. In addition, metal atoms also include semimetal atoms. Examples of derivatives of trivalent or tetravalent metal atoms represented by M include AlCl, AlBr, AlI, AlOH, InCl, InBr, InI, InOH, SiCl ₂ , SiBr ₂ , SiI ₂ , Si(OH) ₂ , GeCl ₂ , GeBr ₂ , GeI ₂ , SnCl ₂ , SnBr ₂ , SnI ₂ , Sn(OH) ₂ , VO, TiO, etc.

As M, _H2 (two hydrogen atoms), Pd, Cu, Zn, Pt, Ni, Co, Fe, Mn, Sn, In, _SnCl2 , AlCl, VO and TiO are preferred, and VO is more preferred.

The lower limit of n is preferably 4. The upper limit of n is preferably 5, and more preferably 4. Multiple n's may be the same or different, but are preferably the same.

The lower limit of the maximum absorption wavelength of the phthalocyanine compound represented by formula (3) is preferably 680 nm, more preferably 700 nm, and even more preferably 720 nm. On the other hand, the upper limit of this maximum absorption wavelength is preferably 1,000 nm, more preferably 900 nm, even more preferably 800 nm, and even more preferably 750 nm. By having the maximum absorption wavelength of the phthalocyanine compound represented by formula (3) in the above range, an optical filter having better properties in terms of visible light transmittance and infrared shielding properties can be formed.

The method for synthesizing the phthalocyanine compound represented by formula (3) is not particularly limited, and it can be synthesized by combining known methods. For example, it can be synthesized by reacting a phthalonitrile compound represented by the following formula (i) or a 1,3-diiminoisoindoline compound represented by formula (ii) with a metal or a metal derivative.

In formulae (i) and (ii), R ^a , R ^b and n have the same meanings as in formula (3).

Metals or metal derivatives include Al, Si, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ge, Ru, Rh, Pd, In, Sn, Pt, Pb, and their halides, carboxylates, sulfates, nitrates, carbonyl compounds, oxides, complexes, etc. Among these, metal halides and carboxylates are particularly preferred. Examples of these include copper chloride, copper bromide, copper iodide, nickel chloride, nickel bromide, nickel acetate, cobalt chloride, iron chloride, zinc chloride, zinc bromide, zinc iodide, zinc acetate, vanadium chloride, vanadium oxychloride, palladium chloride, palladium acetate, aluminum chloride, manganese chloride, lead chloride, lead acetate, indium chloride, titanium chloride, tin chloride, etc.

The reaction temperature is, for example, 60 to 300°C, preferably 100 to 220°C. The reaction time is, for example, 30 minutes to 72 hours, preferably 1 hour to 48 hours. It is preferable to use a solvent in the reaction. The solvent used in the reaction is preferably an organic solvent with a boiling point of 60°C or higher, more preferably an organic solvent with a boiling point of 80°C or higher.

Examples of organic solvents that can be used include alcohol solvents such as methanol, ethanol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-dodecanol, benzyl alcohol, ethylene glycol, propylene glycol, ethoxyethanol, propoxyethanol, butoxyethanol, dimethylethanol, and diethylethanol, and high-boiling point solvents such as dichlorobenzene, trichlorobenzene, chloronaphthalene, sulfolane, nitrobenzene, quinoline, DMI (1,3-dimethyl-2-imidazolidinone), and urea.

The reaction is carried out in the presence or absence of a catalyst, but is preferably carried out in the presence of a catalyst. The catalyst can be an inorganic catalyst such as ammonium molybdate, or a basic organic catalyst such as DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) or DBN (1,5-diazabicyclo[4.3.0]non-5-ene).

In the case of a phthalocyanine compound in which M in formula (3) is two hydrogen atoms, the compound can be produced by reacting a phthalonitrile compound represented by formula (i) or a 1,3-diiminoisoindoline compound represented by formula (ii) with metallic sodium or metallic potassium under the above reaction conditions, and then removing the central metal, sodium or potassium, with hydrochloric acid, sulfuric acid, or the like.

After the reaction is complete, the solvent is distilled off or the reaction solution is poured into a poor solvent for the phthalocyanine compound to precipitate the target product, and the precipitate is filtered to obtain the phthalocyanine compound represented by formula (3). If necessary, the target product can be obtained with a higher purity by further purifying the product using a known purification method such as recrystallization or column chromatography.

The phthalonitrile compound represented by formula (i) and the 1,3-diiminoisoindoline compound represented by formula (ii) can be synthesized by referring to known methods. For example, they can be synthesized by referring to the method described in JP-A-2003-516421.

As the (E-1) dye, it is preferable to use a phthalocyanine compound represented by formula (3) in combination with another phthalocyanine compound. The lower limit of the maximum absorption wavelength of the other phthalocyanine compound is preferably 600 nm, more preferably 650 nm. On the other hand, the upper limit of the maximum absorption wavelength of the other phthalocyanine compound is preferably 900 nm, more preferably 850 nm, more preferably 800 nm, and even more preferably 750 nm. The lower limit of the difference between the maximum absorption wavelength of the phthalocyanine compound represented by formula (3) and the maximum absorption wavelength of the other phthalocyanine compound is preferably 10 nm, more preferably 30 nm. On the other hand, the upper limit of this difference is preferably 100 nm, more preferably 80 nm, and even more preferably 60 nm. Examples of the other phthalocyanine compound include various phthalocyanine compounds known in the art.

The lower limit of the content of the phthalocyanine compound represented by formula (3) in the (E-1) dye is preferably 50% by mass, more preferably 60% by mass, even more preferably 70% by mass, and even more preferably 80% by mass. On the other hand, the upper limit of the content may be 100% by mass, 99% by mass, 90% by mass, or 80% by mass.

The lower limit of the content of the other phthalocyanine compounds in the (E-1) dye is preferably 1% by mass, more preferably 10% by mass, and even more preferably 20% by mass. On the other hand, the upper limit of the content is preferably 50% by mass, and more preferably 40% by mass.

The lower limit of the content of the dye (E-1) in the total solid content of the curable composition is preferably 1 mass%, more preferably 2 mass%, even more preferably 3 mass%, and even more preferably 4 mass%. On the other hand, the upper limit of this content is preferably 20 mass%, more preferably 15 mass%, even more preferably 10 mass%, and even more preferably 8 mass%. By setting the content of the dye (E-1) in the above range, the properties of the obtained optical filter regarding visible light transmittance and infrared shielding property become better.

[(E-2) Dye]
The dye (E-2) may be an inorganic pigment. The dye (E-2), which is an inorganic pigment, is usually in the form of particles and is present in the curable composition in a dispersed state.

The (E-2) dye is preferably an oxide of a metal or semimetal (such as silicon). Specifically, the (E-2) dye is preferably cesium tungsten oxide, quartz, magnetite, alumina, titania, zirconia, spinel, tin-doped indium oxide, antimony-doped tin oxide, or a combination thereof. These inorganic compounds can be used alone or in combination of two or more.

Among these, cesium tungsten oxide is preferred as the (E-2) dye. Cesium tungsten oxide is an infrared shielding agent that has high absorption (i.e., high infrared shielding properties) for infrared rays (especially infrared rays with wavelengths longer than 900 nm and shorter than 2,000 nm) and low absorption for visible light. Therefore, by using cesium tungsten oxide, it is possible to improve the infrared shielding properties while maintaining good visible light transmittance of the resulting optical filter.

Cesium tungsten oxide can be represented, for example, by the following formula (a).
Cs _x WO _y ...(a)
In formula (a), 0.001≦x≦1.1, and 2.2≦y≦3.0.

When x in the above formula (a) is 0.001 or more, infrared rays can be sufficiently shielded. The lower limit of x is preferably 0.01, and more preferably 0.1. On the other hand, when x is 1.1 or less, it is possible to more reliably prevent the generation of an impurity phase in cesium tungsten oxide. The upper limit of x is preferably 1, and more preferably 0.5.

When y in the above formula (a) is 2.2 or more, the chemical stability of the material can be further improved. The lower limit of y is preferably 2.5. On the other hand, when y is 3.0 or less, infrared rays can be sufficiently shielded.

A specific example of the cesium tungsten oxide represented by the above formula ₍ a) is _Cs0.33WO3 .

The (E-2) dye is preferably a fine particle. The upper limit of the average particle size (D50) of the (E-2) dye is preferably 500 nm, more preferably 200 nm, even more preferably 50 nm, even more preferably 30 nm, and even more preferably 20 nm. By having the average particle size be equal to or less than the above upper limit, the generation of aggregated foreign matter can be suppressed and visible light transmittance can be further improved. On the other hand, for reasons such as ease of handling during production, the average particle size of the (E-2) dye is usually 1 nm or more, and may be 10 nm or more. Note that this average particle size (D50) is the secondary particle size in the curable composition.

The (E-2) dye can be synthesized by known methods, but is also available as a commercial product. For example, cesium tungsten oxide is also available as a dispersion of cesium tungsten oxide fine particles such as "YMF-02" from Sumitomo Metal Mining Co., Ltd.

The lower limit of the content of the dye (E-2) in the total solid content of the curable composition is preferably 1 mass%, more preferably 5 mass%, and even more preferably 10 mass%. On the other hand, the upper limit of this content is preferably 50 mass%, more preferably 40 mass%, more preferably 30 mass%, and even more preferably 20 mass%. By setting the content of the dye (E-2) in the above range, the properties of the obtained optical filter regarding visible light transmittance and infrared shielding property are improved.

The lower limit of the mass ratio ([E-2]/[E-1]) of the content of the (E-2) dye to the content of the (E-1) dye is preferably 1, and more preferably 2. On the other hand, the upper limit of this mass ratio ([E-2]/[E-1]) is preferably 40, more preferably 20, and even more preferably 10. By setting the content ratio of the (E-1) dye to the (E-2) dye within the above range, the visible light transmittance and infrared shielding properties of the obtained optical filter are improved.

[Additives]
The curable composition may contain various additives, if necessary, in addition to the above-mentioned components (A) to (E).

Additives include, for example, surfactants, adhesion promoters, UV absorbers, aggregation inhibitors, residue improvers, developability improvers, and reaction regulators.

Examples of surfactants include fluorosurfactants and silicone surfactants.

Examples of adhesion promoters include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

Examples of ultraviolet absorbers include 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole and alkoxybenzophenones.

An example of an anti-aggregation agent is sodium polyacrylate.

Examples of residue improvers include malonic acid, adipic acid, itaconic acid, citraconic acid, fumaric acid, mesaconic acid, 2-aminoethanol, 3-amino-1-propanol, 5-amino-1-pentanol, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, and 4-amino-1,2-butanediol.

Examples of developability improvers include mono[2-(meth)acryloyloxyethyl] succinate, mono[2-(meth)acryloyloxyethyl] phthalate, ω-carboxypolycaprolactone mono(meth)acrylate, and the like.

Examples of reaction regulators include multifunctional thiols.

The lower limit of the content of the components other than the above-mentioned components (A) to (E) in the total solid content of the curable composition is preferably 0.1 mass %, more preferably 1 mass %. On the other hand, the upper limit of this content is preferably 10 mass %, more preferably 5 mass %.

[Preparation method]
The method for preparing the curable composition is not particularly limited, and the curable composition can be prepared by mixing the components. For example, when the curable composition contains the dye (E-2), a method can be adopted in which a dispersion containing the dye (E-2) is first prepared, and other components are added to the dispersion and mixed. The dispersion or the curable composition can be filtered as necessary to remove aggregates.

[Optical filter]
The curable composition is suitable for use in optical filters. That is, the curable composition can be suitably used as a material for forming an optical filter or a shielding film provided in an optical filter. The curable composition can suitably form a shielding film in an optical filter. The optical filter obtained by using the curable composition has good shielding properties for ultraviolet rays close to the visible light region, good transmittance and heat resistance for visible light, and has few defects such as foreign matter. Furthermore, when the curable composition contains a dye (E), the obtained optical filter can exhibit good infrared shielding properties.

The optical filter can be formed, for example, by the following method. First, the curable composition is applied onto a support, and then pre-baked to evaporate the solvent and form a coating film. Next, the coating film is exposed to light and developed using a developer to dissolve and remove the non-exposed parts of the coating film. Then, post-baking is performed to obtain an optical filter having a shielding film patterned into a predetermined shape. Note that the development process does not have to be performed, and in this case, a non-patterned shielding film can be formed.

The support on which the curable composition is applied corresponds to the transparent substrate, microlens, color filter, etc. The application can be performed by any suitable application method such as spraying, roll coating, rotary coating (spin coating), slit die coating (slit coating), bar coating, etc.

The conditions for heating and drying during pre-baking are, for example, 70°C to 110°C and 1 minute to 10 minutes.

Examples of the radiation source used for exposing the coating film include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, medium pressure mercury lamps, and low pressure mercury lamps, and laser light sources such as argon ion lasers, YAG lasers, XeCl excimer lasers, and nitrogen lasers. Ultraviolet LEDs can also be used as the exposure light source. The wavelength of the radiation is preferably in the range of 190 nm to 450 nm. The radiation exposure amount is generally about 10 J/ ^m2 to 50,000 J/ ^m2 .

The developer is generally an alkaline developer. Preferred alkaline developers are aqueous solutions of, for example, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo-[4.3.0]-5-nonene, etc. Appropriate amounts of water-soluble organic solvents, such as methanol and ethanol, and surfactants, etc., can also be added to the alkaline developer. After development, the film is usually washed with water.

The development process can be performed using a shower development method, a spray development method, a dip (immersion) development method, a puddle (liquid puddle) development method, etc. The development conditions are 5 seconds or more and 300 seconds or less at room temperature.

The heating temperature in the post-baking is, for example, from 120° C. to 280° C., and preferably from 180° C. to 250° C. By carrying out such a post-baking (heat treatment), the curing proceeds and the protective group (-R ⁷ -R ⁸ ) of the compound (B) is eliminated. Therefore, the compound (B) can exhibit good radical scavenging ability in the obtained shielding film. The heating time in the post-baking is, for example, from about 1 minute to about 60 minutes.

The lower limit of the average thickness of the shielding film thus formed is usually 0.5 μm, preferably 1 μm. On the other hand, the upper limit of this average thickness is usually 10 μm, preferably 5 μm. By having the average thickness of the shielding film within the above range, a good balance between the shielding properties for ultraviolet and infrared rays and the transmittance of visible light is achieved.

The optical filter may consist of only the shielding film, or may consist of the shielding film and other components. For example, the optical filter may be a laminate having the shielding film and other layers.

It is preferable that the shielding film is incorporated as one component in an optical sensor such as a solid-state imaging element. In this case, the shielding film functions as an optical filter by itself. By incorporating the shielding film in the optical sensor, it is possible to obtain a large process margin, which is preferable. When the shielding film is incorporated in a solid-state imaging element, the shielding film can be disposed, for example, on the outer surface side of the microlens of the solid-state imaging element, between the microlens and the color filter, or between the color filter and the photodiode. It is preferable that the shielding film is laminated between the microlens and the color filter or between the color filter and the photodiode.

The optical filter may be formed by laminating the infrared shielding film on the surface of a transparent substrate. The transparent substrate may be made of glass or a transparent resin. Examples of the transparent resin include polycarbonate, polyester, aromatic polyamide, polyamideimide, and polyimide. Such an optical filter is also suitable for use as an infrared cut filter in a solid-state imaging device.

Optical sensors such as solid-state imaging devices equipped with the above optical filters are useful in digital still cameras, mobile phone cameras, digital video cameras, PC cameras, surveillance cameras, automotive cameras, personal digital assistants, personal computers, video games, medical equipment, etc.

[Optical sensor]
The optical filter is used in optical sensors such as solid-state imaging devices. The optical filter has few defects such as foreign matter and has good properties in terms of visible light transmittance, ultraviolet shielding property, and infrared shielding property, so that optical sensors such as solid-state imaging devices having the optical filter have high sensitivity, color reproducibility, and other properties, and are excellent in practical use.

Below, a solid-state imaging element will be described as an example of an optical sensor. The solid-state imaging element generally has a structure in which a layer in which multiple photodiodes are arranged, a color filter, and a microlens are stacked in this order. A planarizing layer may be provided between these layers. In the solid-state imaging element, light is incident from the microlens side. The incident light passes through the microlens and the color filter to reach the photodiode. Note that the color filters are configured such that only light in a specific wavelength range passes through each of the R (red), G (green), and B (blue) filters, for example.

In the solid-state imaging device, the optical filter (shielding film) can be provided on the outer surface side of the microlens, between the microlens and the color filter, between the color filter and the layer in which the multiple photodiodes are arranged, etc. The optical filter is preferably laminated between the microlens and the color filter or between the color filter and the photodiode. Note that another layer (such as a planarizing layer) may be provided between the optical filter and the microlens, color filter, photodiode, etc.

Specific examples of such solid-state imaging elements include CCDs and CMOSs used as camera modules. Such solid-state imaging elements are useful in digital still cameras, mobile phone cameras, digital video cameras, PC cameras, surveillance cameras, automotive cameras, personal digital assistants, personal computers, video games, medical equipment, etc.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Synthesis Example 1 Synthesis of Dye (E-1-1) 32.9 g of 4,7-bis(4-(2,6-dimethoxyphenoxy)butyl)-1,3-diiminobenzoisoindoline, 4.76 g of vanadium trichloride, and 13.74 g of DBU were stirred in 100 mL of 1-pentanol at an internal temperature of 125° C. for 24 hours. Then, 600 mL of methanol was added, and the precipitate was collected by filtration and dried. The mixture was purified by column chromatography (silica gel/toluene) to obtain 11.2 g of a green powder. The obtained compound was confirmed to be the desired phthalocyanine compound represented by the following formula (E-1-1) from the following analytical results.
・MS: (EI) m/z 2245M+
Elemental analysis: Measured value (C: 68.44%, H: 6.44%, N: 4.99%);
Theoretical value (C: 68.47%, H: 6.46%, N: 4.99%)
The toluene solution of the compound thus obtained showed maximum absorption at 734.5 nm and a gram absorption coefficient of 6.75×10 ⁴ mL/g·cm.

なお、上記式中、「＊」は、結合手を示す（以下の化学式においても同様）。

In the above formula, "*" indicates a bond (the same applies to the following chemical formulas).

Synthesis Example 2: Synthesis of dye (E-1-2) 14.5 g of a green powder was obtained in the same manner as in Synthesis Example 1, except that 18.6 g of 4,7-bis(4-methoxybutyl)-1,3-diiminobenzoisoindoline was used instead of 32.9 g of 4,7-bis(4-(2,6-dimethoxyphenoxy)butyl)-1,3-diiminobenzoisoindoline in Synthesis Example 1. The obtained compound was confirmed to be the target phthalocyanine compound represented by the following formula (E-1-2) from the following analytical results.
・MS: (EI) m/z 1267M+
Elemental analysis: Measured value (C: 68.20%, H: 7.66%, N: 8.82%);
Theoretical value (C: 68.17%, H: 7.63%, N: 8.83%)
The toluene solution of the compound thus obtained showed maximum absorption at 734.0 nm and a gram absorption coefficient of 1.21×10 ⁵ mL/g·cm.

Synthesis Example 3 Synthesis of Cesium Tungsten Oxide (E-2-1) Powder Cesium tungsten oxide (Cs _0.33 WO ₃ ) powder was synthesized using the method described in paragraph [0113] of Japanese Patent No. 4,096,205.

Synthesis Example 4: Synthesis of polymer (C-2-1) In a reaction vessel, 14 parts by mass of benzyl methacrylate, 10 parts by mass of styrene, 12 parts by mass of N-phenylmaleimide, 15 parts by mass of 2-hydroxyethyl methacrylate, 29 parts by mass of 2-ethylhexyl methacrylate, and 20 parts by mass of methacrylic acid were dissolved in 200 parts by mass of propylene glycol monomethyl ether acetate, and 3 parts by mass of 2,2'-azoisobutyronitrile and 5 parts by mass of α-methylstyrene dimer were further added. After purging the reaction vessel with nitrogen, the mixture was heated at 80°C for 5 hours while stirring and bubbling with nitrogen to obtain a solution containing polymer (C-2-1) (polymer solution [C-2-1]: solid content concentration 35% by mass). The molecular weight of the obtained polymer (C-2-1) was measured in terms of polystyrene using a Showa Denko gel permeation chromatography (GPC) apparatus (GPC-104 type, column: three Showa Denko LF-604 columns and KF-602 combined, developing solvent: tetrahydrofuran), and the weight average molecular weight (Mw) was 9,700, the number average molecular weight (Mn) was 5,700, and Mw/Mn was 1.70. In this synthesis example, the charge ratio (mass ratio) of each monomer and the content ratio (mass ratio) of the structural units derived from each monomer in the obtained polymer as a binder can be considered to be substantially the same (the same applies to the following synthesis examples).

Synthesis Example 5: Synthesis of polymer (C-2-2) 200 parts by mass of propylene glycol monomethyl ether was charged into a flask equipped with a cooling tube and a stirrer, and the temperature was raised to 80°C. At the same temperature, a mixed solution of 100 parts by mass of propylene glycol monomethyl ether, 100 parts by mass of methacrylic acid, and 5 parts by mass of 2,2'-azoisobutyronitrile was dropped over 3 hours, and the temperature was maintained after the dropwise addition to polymerize for 3 hours. Thereafter, the temperature of the reaction solution was raised to 100-120°C, and the reaction was carried out for another 2 hours. After cooling, 25 parts by mass of propylene glycol monomethyl ether, 116 parts by mass of 3,4-epoxycyclohexylmethyl acrylate, and a catalytic amount of dimethylbenzylamine were added, and the temperature was raised to 110°C and the reaction was carried out for 9 hours, to obtain a solution containing polymer (C-2-2) (polymer solution [C-2-2]: solid content concentration 40% by mass). The molecular weight of the resulting polymer (C-2-2) was measured in the same manner as in Synthesis Example 4, and it was found that the weight average molecular weight (Mw) was 15,100, the number average molecular weight (Mn) was 7,000, and Mw/Mn was 2.16.

Synthesis Example 6: Synthesis of polymer (C-2-3) 200 parts by mass of propylene glycol monomethyl ether was charged into a flask equipped with a cooling tube and a stirrer, and the temperature was raised to 80°C. At the same temperature, a mixed solution of 200 parts by mass of propylene glycol monomethyl ether, 67 parts by mass of methacrylic acid, 33 parts by mass of N-cyclohexylmaleimide, and 5 parts by mass of 2,2'-azoisobutyronitrile was dropped over 3 hours, and the temperature was maintained after the dropwise addition to polymerize for 3 hours. Thereafter, the temperature of the reaction solution was raised to 100-120°C, and the reaction was carried out for another 3 hours. After cooling, 28 parts by mass of propylene glycol monomethyl ether, 119 parts by mass of 3,4-epoxycyclohexylmethyl acrylate, and a catalytic amount of dimethylbenzylamine were added, and the temperature was raised to 110°C and the reaction was carried out for 30 hours, to obtain a solution containing polymer (C-2-3) (polymer solution [C-2-3]: solid content concentration 40% by mass). The molecular weight of the resulting polymer (C-2-3) was measured in the same manner as in Synthesis Example 4, and it was found that the weight average molecular weight (Mw) was 17,000, the number average molecular weight (Mn) was 7,700, and Mw/Mn was 2.21.

Synthesis Example 7 Synthesis of Polymer (C-2-4) In a flask equipped with a cooling tube and a stirrer, 5 parts by mass of 2,2-azobisisobutyronitrile, 140 parts by mass of methyl 3-methoxypropionate, and 60 parts by mass of propylene glycol monomethyl ether were charged, and 32 parts by mass of glycidyl methacrylate, 40 parts by mass of 3-methacryloxypropyltriethoxysilane, 11 parts by mass of benzyl methacrylate, 3 parts by mass of n-butyl methacrylate, and 14 parts by mass of methacrylic acid were charged and substituted with nitrogen. The temperature of the solution was then raised to 80° C. while gently stirring. The solution was maintained at this temperature for 5 hours to polymerize, thereby obtaining a solution containing polymer (C-2-4) (polymer solution [C-2-4] solids concentration 35% by mass). The molecular weight of the resulting polymer as a binder was measured in the same manner as in Synthesis Example 4, and it was found that the weight average molecular weight (Mw) was 9,500, the number average molecular weight (Mn) was 5,800, and Mw/Mn was 1.64.

Synthesis Example 8: Synthesis of polymer (C-2-5) 600 parts by mass of propylene glycol monomethyl ether and 20 parts by mass of propylene glycol methyl ethyl acetate were charged into a flask equipped with a cooling tube and a stirrer, and the temperature was raised to 80°C. At the same temperature, a mixed solution of 100 parts by mass of propylene glycol monomethyl ether, 60 parts by mass of propylene glycol methyl ethyl acetate, 41 parts by mass of methacrylic acid, 8 parts by mass of benzyl methacrylate, 8 parts by mass of styrene, 21 parts by mass of N-phenylmaleimide, 17 parts by mass of 2-hydroxyethyl methacrylate, 4 parts by mass of 2-ethylhexyl methacrylate, and 8 parts by mass of 2,2'-azoisobutyronitrile was dropped over 3 hours, and the temperature was maintained after the dropwise addition to polymerize for 3 hours. Thereafter, the temperature of the reaction solution was raised to 100 to 120°C, and the reaction was further carried out for 1 hour. After cooling, 20 parts by mass of propylene glycol monomethyl ether, 41 parts by mass of 3,4-epoxycyclohexylmethyl acrylate, and a catalytic amount of dimethylbenzylamine were added, and the mixture was heated to 110° C. and reacted for 12 hours to obtain a solution containing a polymer (C-2-5) (polymer solution [C-2-5]: solid content concentration 35% by mass). The molecular weight of the obtained polymer (C-2-5) was measured in the same manner as in Synthesis Example 4, and the weight average molecular weight (Mw) was 16,000, the number average molecular weight (Mn) was 5,800, and Mw/Mn was 2.76.

Synthesis Example 9: Synthesis of dispersant (β) According to the method described in the literature (Macromolecules 1992, 25, p5907-5913), 45 parts by mass of dimethylaminoethyl methacrylate, 20 parts by mass of 2-ethylhexyl methacrylate, 5 parts by mass of n-butyl methacrylate, and 30 parts by mass of PME-200 (methoxypolyethylene glycol monomethacrylate, and a compound represented by CH ₂ ═C(CH ₃ )COO(C ₂ H ₄ O) _n -CH ₃ (n≒4)) were polymerized in one batch to obtain a reaction solution containing a random copolymer. Subsequently, the reaction solution was quenched using methanol, and the resulting reaction solution was washed with a 7% by mass aqueous solution of sodium bicarbonate and then with water. Thereafter, the solvent was replaced with propylene glycol monomethyl ether acetate (PGMEA), and a dispersant solution [β] containing dispersant (β) was obtained in a yield of 80% by mass. The amine value of the obtained dispersant (β) was 160 mgKOH/g, Mw was 9,500, Mw/Mn was 1.21, and the solid content of the dispersant solution [β] was 39.6 mass%.

The components used are shown below.
Compound (A-1)
A compound represented by the following formula, which is described as Compound No. 1 in paragraph [0037] of International Publication No. 2017/169819:

Compound (A-2)
A compound represented by the following formula, which is described as Compound No. 2 in paragraph [0037] of International Publication No. 2017/169819:

Compound (A-3)
A compound represented by the following formula, which is described as Compound No. 8 in paragraph [0037] of International Publication No. 2017/169819:

Compound (A'-1)
A compound represented by the following formula, which is described as Compound No. 26 in paragraph [0035] of Japanese Patent No. 4818458:

Compound (A'-2)
A compound represented by the following formula: "Irgacure OXE01" (manufactured by BASF)

Compound (A'-3)
A compound represented by the following formula, which is described as Compound No. 5 in paragraph [0017] of JP2014-227533A:

Compound (B-1)
A compound represented by the following formula described in the bottom left section of paragraph [0076] of International Publication No. 2014/021023:

Compound (B-2)
A compound represented by the following formula described in the bottom right corner of paragraph [0076] of International Publication No. 2014/021023:

Compound (B-3)
A compound represented by the following formula described in the top paragraph of paragraph [0077] of International Publication No. 2014/021023:

Compound (B'-1)
A compound represented by the following formula: "Irganox 1010" (manufactured by BASF)

・Polymerizable compound (C-1-1)
Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (C-1-1) "KAYARAD DPHA" (manufactured by Nippon Kayaku Co., Ltd.)

・Polymer (C-2-1) to (C-2-5)
Polymers (C-2-1) to (C-2-5) obtained in Synthesis Examples 4 to 8 above

Solvent (D-1)
Cyclopentanone (CPN)

Solvent (D-2)
Propylene glycol monomethyl ether acetate (PGMEA)

Dyes (E-1-1) to (E-1-2)
Phthalocyanine dyes (E-1-1) to (E-1-2) obtained in Synthesis Examples 1 and 2 above

Dye (E-1-3)
Phthalocyanine dye (E-1-3) described in Example 1 of JP-A-05-25177 (maximum absorption wavelength: 692 nm)

Dye (E-2-1)
Cesium tungsten oxide (E-2-1) obtained in Synthesis Example 3 above

Dispersant solution [α]
"BYK-LPN6919" manufactured by BYK Chemie (solid content concentration 60% by mass, amine value 120 mgKOH/g)

Dispersant solution [β]
Dispersant solution [β] obtained in Synthesis Example 9

Additive (F-1)
Fluorosurfactant "FTX-218D" (manufactured by Neos Co., Ltd.)

Additive (F-2)
A multifunctional thiol called Karenz MT PEI (manufactured by Showa Denko Co., Ltd.) is used as a reaction regulator.

All ingredients not listed in the above synthesis examples and ingredients without trade names are either commercially available products or compounds synthesized by known methods.

[Preparation Example 1] Preparation of pigment dispersion (dispersion [E-2-1]) 25.00 parts by mass of cesium tungsten oxide (E-2-1), 13.30 parts by mass of dispersant solution [α], and 61.70 parts by mass of CPN as a solvent (dispersion medium) were prepared. These were filled into a container together with 2,000 parts by mass of zirconia beads having a diameter of 0.1 mm, and dispersed with a paint shaker to obtain a dispersion [E-2-1] having an average particle diameter (D50) of 19 nm. The average particle diameter was measured by the DLS method using a light scattering measuring device (ALV-5000 from ALV, Germany).

[Preparation Example 2] Preparation of pigment dispersion (dispersion [E-2-2]) A dispersion [E-2-2] having an average particle size of 19 nm was obtained in the same manner as in Preparation Example 1, except that the dispersant solution was changed to 20.20 parts by mass of dispersant solution [β] and the solvent was changed to 54.80 parts by mass of CPN.

[Preparation Example 3] Preparation of dye solution (solution [E-1-1], etc.) 7.00 parts by mass of dye (E-1-1) and 93.00 parts by mass of CPN as a solvent were weighed into a container and mixed with a stirrer. The obtained solution was filtered under a constant pressure condition of 0.05 MPa using a 0.2 μm PTFE filter to obtain a solution [E-1-1] containing dye (E-1-1).
Furthermore, solutions [E-1-2] and [E-1-3] were obtained in the same manner except that dye (E-1-1) was replaced with dye (E-1-2) or dye (E-1-3).

Preparation Example 4 Preparation of Surfactant Solution (Solution [F-1]) 5.00 parts by mass of additive (F-1) as a surfactant and 95.00 parts by mass of CPN as a solvent were weighed into a container and mixed with a stirrer to obtain a solution [F-1] containing a surfactant.

[Preparation Example 5] Preparation of reaction adjuster solution (solution [F-2]) 5.00 parts by mass of additive (F-2) as a reaction adjuster and 95.00 parts by mass of CPN as a solvent were weighed into a container and mixed with a stirrer to obtain a solution [F-2] containing a reaction adjuster.

Preparation Example 6 Preparation of Antioxidant Solution (Solution [B-1], etc.) 5.00 parts by mass of compound (B-1) and 95.00 parts by mass of CPN as a solvent were weighed into a container and mixed with a stirrer to obtain solution [B-1] containing compound (B-1).
In addition, solutions [B-2], [B-3] and [B'-1] were obtained in the same manner except that compound (B-2), compound (B-3) or compound (B'-1) was used instead of compound (B-1).

[Example 1]
1.6 parts by mass of compound (A-1),
Solution [B-1] 4.3 parts by mass,
8 parts by mass of polymerizable compound (C-1-1),
22.9 parts by mass of solution [C-2-1],
Solvent (D-1) 17.5 parts by mass Solution [E-1-1] 21.1 parts by mass
Dispersion liquid [E-2-1] 16.6 parts by mass,
1.6 parts by mass of solution [F-1] and 6.4 parts by mass of solution [F-2] were weighed into a container and mixed with a stirrer. Approximately 100 mL of this mixture was filtered under a constant pressure of 0.05 MPa using a 0.5 μm PTFE (polytetrafluoroethylene) filter to obtain the curable composition of Example 1.

[Examples 2 to 17, Comparative Examples 1 to 4]
The curable compositions of Examples 2 to 17 and Comparative Examples 1 to 4 were obtained in the same manner as in Example 1, except that the types and amounts of each component blended were as shown in Tables 1 and 2. Components other than (A), (A'), (C-1), and (D) were blended in the state of a solution or dispersion, and Tables 1 and 2 show the blending amounts of the solution or dispersion. In Tables 1 and 2, components blended as a solution or dispersion are shown in square brackets [ ]. In addition, for the curable compositions of Examples 1, 11, 14, 15, and 20 and Comparative Example 1, the average polymerizable double bond equivalent of the binder is also shown.

[evaluation]
The following evaluations were carried out using each of the obtained curable compositions. The evaluation results are shown in Tables 1 and 2.

Each curable composition was applied to a glass substrate by spin coating to a predetermined thickness. The coating was then heated at 100°C for 120 seconds and exposed to 500 mJ/ ^cm2 with an i-line stepper. The coating was then heated at 220°C for 300 seconds to prepare a shielding film having an average thickness of 3.0 μm on the glass substrate. The film thickness was measured with a stylus stepper (Yamato Scientific Co., Ltd.'s "Alpha Step IQ"). Next, the transmittance in each wavelength region of the shielding film prepared on the glass substrate was measured relative to the glass substrate using a spectrophotometer (JASCO Corporation's "V-7300"). Evaluation was performed based on the obtained spectrum according to the following evaluation criteria.

(Ultraviolet light shielding property)
The average transmittance from 350 to 395 nm was calculated. When the average transmittance is less than 30%, it is estimated that the filter has high noise shielding function and is highly practical when used as an optical filter. The average transmittance was evaluated according to the following criteria.
A: Less than 25% B: 25% to less than 30% C: 30% or more

(Visible light transmittance)
The average transmittance from 430 to 600 nm was calculated. If the average transmittance is less than 80%, the sensitivity decreases when used as an optical filter. The average transmittance was evaluated according to the following criteria.
A: 85% or more B: 80% or more but less than 85% C: Less than 80%

(Infrared shielding property 1)
The range in which the transmittance in the range of 700-900 nm was continuously 20% or less was determined. When the range in which the transmittance was continuously 20% or less was 40 nm or more, it was estimated that the filter had high noise shielding function and was highly practical when used as an optical filter. The infrared shielding range was also evaluated according to the following criteria.
A: 55 nm or more B: 40 nm or more but less than 55 nm C: Less than 40 nm

(Infrared shielding property 2)
The average transmittance from 900 to 1200 nm was calculated. When the average transmittance is less than 45%, it is estimated that the filter has high noise shielding function and is therefore highly practical when used as an optical filter. The average transmittance was evaluated according to the following criteria.
A: Less than 32% B: 32% to less than 45% C: 45% or more

(Heat resistance up to 260℃)
The shielding film prepared on the glass substrate was heated at 260° C. for 300 seconds using a hot plate, and the transmittance in each wavelength region before and after heating was measured relative to the glass substrate using a spectrophotometer (JASCO Corporation's "V-7300"). At this time, the absorbance at the wavelength at which the transmittance of the prepared infrared shielding film is the lowest in the range of 700-800 nm is (α1), the absorbance at the same wavelength after heating at 260° C. is (α2), and the absorbance retention rate=100×(α1)/(α2) was used to evaluate the heat resistance at 260° C. according to the following criteria. When the retention rate is 80% or more, it is possible to maintain high heat resistance by using it in combination with a protective film or the like when used as a shielding film, and it is presumed to be highly practical.
A: Retention rate is 90% or more. B: Retention rate is 80% or more but less than 90%. C: Retention rate is less than 80%.

(Defect suppression 1)
Each curable composition was applied to a silicon substrate by spin coating, and the coating was cured to form a cured film (shielding film) with a thickness of about 1 μm. The defect density of the cured film was measured using a defect/foreign matter inspection device (KLA-Tencor's "KLA 2351"). It can be determined that the smaller the defect density value, the higher the defect suppression ability. Note that a defect refers to a detection point with a size of 1 μm or more. Based on the defect density, the defect suppression ability was evaluated according to the following criteria.
A: 10/cm ² or less B: 10/cm ² more than 50/cm ² or less C: 50/cm ² or less

(Defect suppression 2)
Each curable composition was stored at 5°C for one month, and then coated on a silicon substrate by spin coating, and the coating was cured to form a cured film (shielding film) having a thickness of about 1 μm. The defect density of the cured film was measured using a defect/foreign matter inspection device (KLA-Tencor's "KLA 2351"). It can be determined that the smaller the defect density value, the higher the defect suppression ability. Note that a defect refers to a detection point having a size of 1 μm or more. Based on the defect density, the defect suppression ability was evaluated according to the following criteria.
A: 10/cm ² or less B: 10/cm ² more than 50/cm ² or less C: 50/cm ² or less

(Solvent resistance)
The transmittance in each wavelength region of the shielding films prepared on the glass substrates using the curable compositions of Examples 1, 11, 14, 15, 20, and Comparative Example 1 before and after immersion in an acetone solution was measured relative to the glass substrate using a spectrophotometer (JASCO Corporation's "V-7300"). At this time, the transmittance at the wavelength at which the transmittance of the prepared shielding films is the lowest in the range of 700-800 nm is (T1), the absorbance at the same wavelength after immersion in acetone is (T2), and the change in transmittance = |(T1)-(T2)| was defined as follows, and the solvent resistance was evaluated according to the following criteria. It is estimated that the smaller the change in transmittance, the higher the practicality when used as a shielding film.
A: The change in transmittance is 1% or less. B: The change in transmittance is more than 1% and less than 5%. C: The change in transmittance is more than 5%.

As shown in Tables 1 and 2, the curable compositions of Examples 1 to 17 can be used to form optical filters that have good ultraviolet shielding properties close to the visible light range, good visible light transmittance, and good heat resistance, and that have few defects such as foreign matter. In addition, the optical filters formed from the curable compositions of Examples 1 to 17 also have good infrared shielding properties.

On the other hand, the optical filters formed from the curable compositions of Comparative Examples 1 to 4 were inferior in at least one of ultraviolet shielding, heat resistance, and defect suppression. Specifically, in Comparative Examples 1 and 2, in which the compound (A'-1) not having a carbazole skeleton to which a nitro group is bonded was used instead of the component (A) represented by formula (1), ultraviolet shielding and the like were poor. In Comparative Example 3, in which the compound (A'-3) was used instead of the component (A) represented by formula (1), heat resistance was poor. The compound (A'-3) has a carbazole skeleton to which a nitro group is bonded, but does not have an oxime ester structure. It is believed that the ultraviolet shielding and heat resistance of the optical filter formed are exhibited by using the compound represented by formula (1). In Comparative Example 4, which contains the component (A) but does not contain the component (B) represented by formula (2), defect suppression was poor.

The curable composition of the present invention can be suitably used as a material for forming an optical filter of an optical sensor such as a solid-state imaging device.

Claims (8)

A first compound represented by the following formula (1):
A second compound represented by the following formula (2):
A binder comprising a compound having a polymerizable group;
solvent,
The present invention comprises a first dye having a maximum absorption wavelength in a wavelength region of 650 nm or more and 900 nm or less, and a second dye having a maximum absorption wavelength in a wavelength region of more than 900 nm and 2,000 nm or less,
The first dye contains a compound represented by the following formula (3):
The binder comprises (C-1) a polymerizable compound and (C-2) a polymer,
the polymerizable compound (C-1) is at least one monomer selected from the group consisting of compounds having two or more (meth)acryloyl groups and compounds having two or more N-alkoxymethylamino groups,
The curable composition , wherein the polymer (C-2) is a polymer having at least one kind of polymerizable group and a ring structure in the main chain .

(In formula (1), R ¹ is a substituted or unsubstituted aryl group having 1 to 30 carbon atoms. R ² and R ³ are each independently a monovalent organic group having 1 to 30 carbon atoms. R ⁴ and R ⁵ are each independently a monovalent organic group having 1 to 30 carbon atoms or a halogen atom. a and b are each independently an integer of 0 to 3. When a is 2 or more, multiple R ^4s may be the same or different. When b is 2 or more, multiple R ^5s may be the same or different.)

(In formula (2), A is a ring structure composed of one or more five-membered or six-membered rings. R ⁶ is a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 40 carbon atoms. ^{R 7} is *-CO-, *-COO-, *-SCO-, *-COS-, *-S-COO-, *-CONH-, *-NHCO-, or *-NHCOO- (* indicates the bonding position with the oxygen atom). ^{R 8} is an alkyl group having 1 to 8 carbon atoms. c is an integer of 0 to 4. d is an integer of 1 to 3. e is an integer of 1 to 10. When e is 1, X is a monovalent organic group, and when e is 2 or more, X is an e-valent linking group. When there are multiple R ⁶ , R ⁷ , or R ⁸ , the multiple R ⁶ , multiple R ⁷ , or multiple R ⁸ may be the same or different.)

(In formula (3), a plurality of R ^a's are each independently an aryl group having a substituent. A plurality of R ^b's are each independently a hydrogen atom, a halogen atom, or an alkyl group. A plurality of R ^b's may be bonded to each other to form an aromatic ring together with the carbon chain to which they are bonded. M is two hydrogen atoms, a divalent metal atom, or a derivative of a trivalent or tetravalent metal atom. A plurality of n's are each independently an integer of 3 to 6.) The curable composition according to claim 1, which is for use in an optical filter. The curable composition according to claim 1 or 2, wherein the substituent in R ^a in the formula (3) is a group having a hetero atom. The curable composition according to claim 3, wherein the group having a heteroatom is a halogen atom, an alkoxy group, or an alkylthio group. The curable composition according to any one of claims 1 to 4, wherein R ⁷ in formula ( 2 ) in the second compound is *-COO-, *-COS-, or *-CONH- (* indicates a bonding position with an oxygen atom). The curable composition according to claim 1 , wherein the solvent comprises a compound having a cyclic structure. The curable composition according to claim 1 , further comprising: a compound having a phenylthio skeleton and an oxime ester structure. The curable composition according to claim 1 , further comprising a compound represented by the following formula (4):

(In formula (4), A' is a ring structure composed of one or more five-membered or six-membered rings. R ⁶ ' is a halogen atom, a hydroxy group, a nitro group, or a monovalent organic group having 1 to 40 carbon atoms. c' is an integer from 0 to 4. d' is an integer from 1 to 3. e' is an integer from 1 to 10. When e' is 1, X' is a monovalent organic group, and when e' is 2 or more, X' is an e'-valent linking group. When there are multiple R ⁶ 's, the multiple R ⁶ 's may be the same or different.)