JP7365940B2 - Varnish composition and method for producing polyimide resin - Google Patents

Description

The present invention relates to a varnish composition and a method for producing a polyimide resin using the varnish composition.

Polyimide resin has properties such as excellent heat resistance, mechanical strength, insulation, and low dielectric constant, so it is used as an insulator in electrical and electronic components such as various elements and electronic boards such as multilayer wiring boards. It is widely used as wood and protection material. Generally, a polyimide resin is formed by heat-treating a solution of polyamic acid obtained by polymerizing a tetracarboxylic dianhydride component and a diamine component at a high temperature.

As a varnish composition for forming a polyimide resin that is a solution of polyamic acid, for example, a varnish composition in which polyamic acid is dissolved in a solvent mixture containing dimethyl sulfoxide, triethyl phosphate, and gamma-butyrolactone is known. (See Patent Document 1).
Polyamic acids are often difficult to dissolve in common organic solvents. However, a solvent mixture containing dimethyl sulfoxide, triethyl phosphate, and gamma-butyrolactone is a good solvent for polyamic acid.

Japanese Patent Application Publication No. 2016-138255

However, the varnish composition containing polyamic acid described in Patent Document 1 has a problem in that it tends to generate odor when storing the varnish composition or when forming a polyimide resin using the varnish composition.

The present invention has been made in view of the above-mentioned problems, and is capable of dissolving polyamic acid well and eliminating odor when storing a varnish composition or forming a polyimide resin using the varnish composition. It is an object of the present invention to provide a varnish composition that is less likely to generate varnish, and a method for producing a polyimide resin using the varnish composition.

In a varnish composition for forming a polyimide resin containing polyamic acid, the present inventors used a nitrogen-containing organic solvent (S-I) and a sulfur-containing organic solvent (S-I), each having a specific structure, as the solvent (S). -II) It was discovered that the above-mentioned problem could be solved, and the present invention was completed. More specifically, the present invention provides the following.

（式（Ｓ１）中、Ｒ^Ｓ１及びＲ^Ｓ２は、それぞれ独立に炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３は、水素原子、又は下記式（Ｓ１－１）若しくは下記式（Ｓ１－２）：

で表される基であり、Ｒ^Ｓ４は、水素原子又は水酸基であり、Ｒ^Ｓ５及びＲ^Ｓ６は、それぞれ独立に、水素原子、炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ７及びＲ^Ｓ８は、それぞれ独立に水素原子、又は炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３が式（Ｓ１－１）で表される基である場合、Ｒ^Ｓ２及びＲ^Ｓ３は、互いに結合して環を形成してもよい。）
で表される含窒素化合物であり、
含硫黄有機溶媒（Ｓ－ＩＩ）が、下記式（Ｓ２）：
Ｒ^Ｓ９－Ｓ（＝Ｏ）_２－Ｒ^Ｓ１０・・・（Ｓ２）
（式（Ｓ２）中、Ｒ^Ｓ９及びＲ^Ｓ１０は、それぞれ独立に、酸素原子、窒素原子、及びハロゲン原子からなる群より選択される１種以上のヘテロ原子を含んでいてもよい有機基であり、Ｒ^Ｓ９及びＲ^Ｓ１０は、互いに結合して環を形成してもよい。）
で表される含硫黄化合物である、ワニス組成物である。 The first aspect of the present invention is
A varnish composition for forming a polyimide resin, comprising a polyamic acid (A) and a solvent (S),
The solvent (S) includes a nitrogen-containing organic solvent (S-I) and a sulfur-containing organic solvent (S-II),
The nitrogen-containing organic solvent (SI) has the following formula (S1):

(In formula (S1), R ^S1 and R ^S2 are each independently an alkyl group having 1 to 3 carbon atoms, and R ^S3 is a hydrogen atom, or the following formula (S1-1) or the following formula (S1 -2):

R ^S4 is a hydrogen atom or a hydroxyl group, R ^S5 and R ^S6 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ^S7 and R ^S8 is each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when R ^S3 is a group represented by formula (S1-1), R ^S2 and R ^S3 are bonded to each other. may be used to form a ring. )
It is a nitrogen-containing compound represented by
The sulfur-containing organic solvent (S-II) has the following formula (S2):
R ^S9 -S(=O) ₂ -R ^S10 ...(S2)
(In formula (S2), R ^S9 and R ^S10 are each independently an organic group that may contain one or more hetero atoms selected from the group consisting of an oxygen atom, a nitrogen atom, and a halogen atom. , R ^S9 and R ^S10 may be combined with each other to form a ring.)
This is a varnish composition that is a sulfur-containing compound represented by:

A second aspect of the present invention includes a molding step of molding the varnish composition according to the first aspect;
This is a method for producing a polyimide resin, including an imidization step of heating and imidizing a molded varnish composition.

According to the present invention, there is provided a varnish composition in which polyamic acid is well dissolved and in which odor does not easily occur during storage of the varnish composition or when forming a polyimide resin using the varnish composition, and the varnish composition. A method for producing a polyimide resin using a polyimide resin can be provided.

≪Varnish composition≫
The varnish composition includes a polyamic acid (A) and a solvent (S). The varnish composition is used to form a polyimide resin.

（式（Ｓ１）中、Ｒ^Ｓ１及びＲ^Ｓ２は、それぞれ独立に炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３は、水素原子、又は下記式（Ｓ１－１）若しくは下記式（Ｓ１－２）：

で表される基であり、Ｒ^Ｓ４は、水素原子又は水酸基であり、Ｒ^Ｓ５及びＲ^Ｓ６は、それぞれ独立に、水素原子、炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ７及びＲ^Ｓ８は、それぞれ独立に水素原子、又は炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３が式（Ｓ１－１）で表される基である場合、Ｒ^Ｓ２及びＲ^Ｓ３は、互いに結合して環を形成してもよい。）
で表される含窒素化合物である。
含硫黄有機溶媒（Ｓ－ＩＩ）は、下記式（Ｓ２）：
Ｒ^Ｓ９－Ｓ（＝Ｏ）_２－Ｒ^Ｓ１０・・・（Ｓ２）
（式（Ｓ２）中、Ｒ^Ｓ９及びＲ^Ｓ１０は、それぞれ独立に、酸素原子、窒素原子、及びハロゲン原子からなる群より選択される１種以上のヘテロ原子を含んでいてもよい有機基であり、Ｒ^Ｓ９及びＲ^Ｓ１０は、互いに結合して環を形成してもよい。）
で表される含硫黄化合物である。 The solvent (S) includes a nitrogen-containing organic solvent (S-I) and a sulfur-containing organic solvent (S-II).
The nitrogen-containing organic solvent (SI) has the following formula (S1):

(In formula (S1), R ^S1 and R ^S2 are each independently an alkyl group having 1 to 3 carbon atoms, and R ^S3 is a hydrogen atom, or the following formula (S1-1) or the following formula (S1 -2):

R ^S4 is a hydrogen atom or a hydroxyl group, R ^S5 and R ^S6 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ^S7 and R ^S8 is each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when R ^S3 is a group represented by formula (S1-1), R ^S2 and R ^S3 are bonded to each other. may be used to form a ring. )
It is a nitrogen-containing compound represented by
The sulfur-containing organic solvent (S-II) has the following formula (S2):
R ^S9 -S(=O) ₂ -R ^S10 ...(S2)
(In formula (S2), R ^S9 and R ^S10 are each independently an organic group that may contain one or more hetero atoms selected from the group consisting of an oxygen atom, a nitrogen atom, and a halogen atom. , R ^S9 and R ^S10 may be combined with each other to form a ring.)
It is a sulfur-containing compound represented by

By containing the above nitrogen-containing organic solvent (S-I) and sulfur-containing organic solvent (S-II) in combination, the varnish composition can reduce odor during storage and during polyimide resin production. Occurrence is suppressed.

In particular, since the solvent (S) contains the sulfur-containing compound represented by the above formula (S2), odor-causing substances can be removed during storage of the varnish composition or when producing polyimide resin using the varnish composition. As a result, the generation of odor in the varnish composition during storage and during polyimide resin production is suppressed.

The essential or optional components of the varnish composition will be explained below.

<Polyamic acid (A)>
The varnish composition contains polyamic acid (A). Polyamic acid (A) is a precursor polymer of polyimide resin produced when the varnish composition is cured. The polyamic acid (A) is not particularly limited as long as it is a resin conventionally used as a precursor polymer for producing polyimide resins.

（式（ａ１）中、Ａ^１は炭素原子数６以上５０以下の４価の有機基であり、Ａ^２は２価の有機基である。） Polyamic acid (A) can usually be obtained by condensing a monomer component consisting of a tetracarboxylic dianhydride and a diamine compound.
The polyamic acid may have a structural unit represented by the following formula (a1).

(In formula (a1), A ¹ is a tetravalent organic group having 6 to 50 carbon atoms, and A ² is a divalent organic group.)

Hereinafter, the tetracarboxylic dianhydride, the diamine compound, and the method for producing polyamic acid (A), which are used for producing polyamic acid (A), will be described below.

（式（ａ１－１）中、Ａ^１は炭素原子数６以上５０以下の４価の有機基である。） [Tetracarboxylic dianhydride]
The tetracarboxylic dianhydride that produces the structural unit represented by formula (a1) is represented by the following formula (a1-1).
The tetracarboxylic dianhydride represented by formula (a1-1) reacts with a diamine compound described below to give a polyamic acid (A) having a structural unit represented by formula (a1). Such tetracarboxylic dianhydrides may be used alone or in combination of two or more.

(In formula (a1-1), A ¹ is a tetravalent organic group having 6 to 50 carbon atoms.)

In formula (a1-1), A ¹ is a tetravalent organic group having 6 to 50 carbon atoms, and is an acid represented by two -CO-O-CO- in formula (a1-1). In addition to the anhydride group, it may have one or more substituents.
Suitable examples of the substituent include a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a fluorinated alkyl group having 1 to 6 carbon atoms, and a fluorinated alkyl group having 1 to 6 carbon atoms. A fluorinated alkoxy group of 1 or more and 6 or less is preferred. Further, the compound represented by formula (a1-1) may contain a carboxy group or a carboxylic acid ester group in addition to the acid anhydride group.
When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferably a perfluoroalkyl group or a perfluoroalkoxy group.
Regarding the above substituents, the same can be said of one or more substituents that the aromatic group described below may have on the aromatic ring.

In formula (a1-1), A ¹ is a tetravalent organic group, and the lower limit of the number of carbon atoms is 6 and the upper limit is 50.
The number of carbon atoms constituting A ¹ is more preferably 8 or more, and even more preferably 12 or more. Further, the number of carbon atoms constituting A ¹ is more preferably 40 or less, and even more preferably 30 or less. A ¹ may be an aliphatic group, an aromatic group, or a combination of these structures. A ¹ may contain a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom in addition to a carbon atom and a hydrogen atom. When A ¹ contains an oxygen atom, nitrogen atom, or sulfur atom, the oxygen atom, nitrogen atom, or sulfur atom is a nitrogen-containing heterocyclic group, -CONH-, -NH-, -N=N-, -CH= A ¹ may include a group selected from N-, -COO-, -O-, -CO-, -SO-, -SO ₂ -, -S-, and -S-S-, It is more preferable that A ¹ includes a group selected from -O-, -CO-, -SO-, -SO ₂ -, -S-, and -SS-.

The tetracarboxylic dianhydride can be appropriately selected from tetracarboxylic dianhydrides that have been conventionally used as raw materials for synthesizing polyamic acids. The tetracarboxylic dianhydride may be an aliphatic tetracarboxylic dianhydride or an aromatic tetracarboxylic dianhydride.

Examples of the aliphatic tetracarboxylic dianhydride include 2,2-bis(3,4-dicarboxy)propane dianhydride, bis(3,4-dicarboxy)methane dianhydride, and the like. Moreover, the aliphatic tetracarboxylic dianhydride may contain an alicyclic structure. The alicyclic structure may be polycyclic. Examples of the polycyclic alicyclic structure include bridged alicyclic structures such as bicyclo[2.2.1]heptane. For example, a bridged alicyclic structure may be fused with another bridged alicyclic structure and/or a non-bridged alicyclic structure, or a bridged alicyclic structure may be fused with another bridged alicyclic structure and/or a non-bridged alicyclic structure. It may be connected to a formula structure and/or a non-bridged alicyclic structure by a spiro bond. When an aliphatic tetracarboxylic dianhydride is used, a cured product with excellent transparency tends to be easily obtained using the composition.

（式（ａ２）中、Ｒ^ａ１１、Ｒ^ａ１２、及びＲ^ａ１３は、それぞれ独立に、水素原子、炭素原子数１以上５以下のアルキル基及びフッ素原子からなる群より選択される１種であり、ａは０以上１２以下の整数である。） Further, as the aliphatic group constituting A ¹ in formula (a1-1), for example, a tetravalent group represented by the following formula (a2) can be employed. When such a group is used, there is a tendency to easily obtain a polyimide resin having excellent transparency.
In addition, from the viewpoint of easy purification of the raw material compound, a in formula (a2) is preferably 5 or less, more preferably 3 or less. Moreover, since the chemical stability of the raw material compound providing the structural unit represented by formula (a1) is excellent, a is preferably 1 or more, and more preferably 2 or more.
In formula (a2), a is particularly preferably 2 or 3.

(In formula (a2), R ^a11 , R ^a12 , and R ^a13 are each independently one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a fluorine atom, a is an integer between 0 and 12.)

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

The aromatic tetracarboxylic dianhydride may also be, for example, a compound represented by the following general formulas (a1-2) to (a1-4).

In formulas (a1-2) and (a1-3) above, R ^a1 , R ^a2 and R ^a3 each represent an aliphatic group optionally substituted with halogen, an oxygen atom, a sulfur atom, one or more It is either an aromatic group via a divalent element, or a divalent group constituted by a combination thereof. R ^a2 and R ^a3 may be the same or different.
That is, R ^a1 , R ^a2 and R ^a3 may contain a carbon-carbon single bond, a carbon-oxygen-carbon ether bond, or a halogen element (fluorine, chlorine, bromine, iodine). Examples of the compound represented by formula (a1-2) include 2,2-bis(3,4-dicarboxyphenoxy)propane dianhydride and 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride. Examples include anhydrides.

Furthermore, in the above formula (a1-4), R ^a4 and R ^a5 are either an aliphatic group which may be substituted with halogen, an aromatic group via one or more divalent elements, or a halogen. , or a combination thereof. R ^a4 and R ^a5 may be the same or different. As the compound represented by formula (a1-4), difluoropyromellitic dianhydride, dichloropyromellitic dianhydride, etc. can also be used.

Examples of the tetracarboxylic dianhydride for obtaining a fluorine-containing polyimide containing fluorine in its molecular structure include (trifluoromethyl)pyromellitic dianhydride and di(trifluoromethyl)pyromellitic dianhydride. , di(heptafluoropropyl)pyromellitic dianhydride, pentafluoroethylpyromellitic dianhydride, bis{3,5-di(trifluoromethyl)phenoxy}pyromellitic dianhydride, 2,2-bis (3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 2,2', 5,5'-tetrakis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4' -Tetracarboxydiphenyl ether dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybenzophenone dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}benzene dianhydride anhydride, bis{(trifluoromethyl)dicarboxyphenoxy}(trifluoromethyl)benzene dianhydride, bis(dicarboxyphenoxy)(trifluoromethyl)benzene dianhydride, bis(dicarboxyphenoxy)bis(trifluoro methyl)benzene dianhydride, bis(dicarboxyphenoxy)tetrakis(trifluoromethyl)benzene dianhydride, 2,2-bis{4-(3,4-dicarboxyphenoxy)phenyl}hexafluoropropane dianhydride, Bis{(trifluoromethyl)dicarboxyphenoxy}biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}bis(trifluoromethyl)biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}diphenyl ether Dianhydride, bis(dicarboxyphenoxy)bis(trifluoromethyl)biphenyl dianhydride, difluoropyromellitic dianhydride, 1,4-bis(3,4-dicarboxytrifluorophenoxy)tetrafluorobenzene dianhydride and 1,4-bis(3,4-dicarboxytrifluorophenoxy)octafluorobiphenyl dianhydride.

As the tetracarboxylic dianhydride, it is preferable to use an alicyclic tetracarboxylic dianhydride in consideration of the heat resistance, transparency, etc. of the resulting polyimide resin.
Note that acid chlorides, esters, and the like of tetracarboxylic acids having the same basic skeleton as these can also be used.

Tetracarboxylic dianhydride may be used in combination with dicarboxylic anhydride. When these carboxylic acid anhydrides are used in combination, the properties of the resulting imide ring-containing polymer such as polyimide resin may become even better. Examples of dicarboxylic anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, and methyltetrahydrophthalic anhydride. Examples include phthalic anhydride, glutaric anhydride, cis-4-cyclohexene-1,2-dicarboxylic anhydride, and the like.

[Diamine compound]
As the diamine compound, a compound represented by the following formula (a3-1) can typically be used. One type of diamine compound may be used alone, or two or more types may be used in combination.
_H2NA2 - ^NH2 _... (a3-1)
(In formula (a3-1), A ² represents a divalent organic group.)

In formula (a3-1), A ² is a divalent organic group, and may have one or more substituents in addition to the two amino groups in formula (a3-1).
Suitable examples of the substituent include a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a fluorinated alkyl group having 1 to 6 carbon atoms, and a fluorinated alkyl group having 1 to 6 carbon atoms. A fluorinated alkoxy group or hydroxyl group of 1 or more and 6 or less is preferred.
When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferably a perfluoroalkyl group or a perfluoroalkoxy group.

In formula (a3-1), the lower limit of the number of carbon atoms in the organic group as A ² is preferably 2, more preferably 6, and the upper limit is preferably 50, more preferably 30.
Although A ² may be an aliphatic group, it is preferably an organic group containing one or more aromatic rings.

When A ² is an organic group containing one or more aromatic rings, the organic group may be the aromatic group 1 itself, and the two or more aromatic groups may be an aliphatic hydrocarbon group or a halogenated aliphatic group. It may be a group bonded via a bond containing a group hydrocarbon group or a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Bonds containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms contained in ^A2 include -CONH-, -NH-, -N=N-, -CH=N-, -COO-, - Examples include O-, -CO-, -SO-, -SO ₂ -, -S-, and -S-S-, and -O-, -CO-, -SO-, -SO ₂ -, -S -, and -SS- are preferred.

The aromatic ring bonded to the amino group in A ² is preferably a benzene ring. When the ring bonded to the amino group in A ² is a condensed ring containing two or more rings, the ring bonded to the amino group in the condensed ring is preferably a benzene ring.
Further, the aromatic ring contained in A ² may be an aromatic heterocycle.

（式（２１）～（２４）中、Ｒ^１１１は、水素原子、フッ素原子、水酸基、炭素原子数１以上４以下のアルキル基、及び炭素原子数１以上４以下のハロゲン化アルキル基よりなる群から選択される１種を示す。式（２４）中、Ｑは、９，９’－フルオレニリデン基、又は、式：－Ｃ_６Ｈ_４－、－ＣＯＮＨ－Ｃ_６Ｈ_４－ＮＨＣＯ－、－ＮＨＣＯ－Ｃ_６Ｈ_４－ＣＯＮＨ－、－Ｏ－Ｃ_６Ｈ_４－ＣＯ－Ｃ_６Ｈ_４－Ｏ－、－ＯＣＯ－Ｃ_６Ｈ_４－ＣＯＯ－、－ＯＣＯ－Ｃ_６Ｈ_４－Ｃ_６Ｈ_４－ＣＯＯ－、－ＯＣＯ－、－Ｏ－、－Ｓ－、－ＣＯ－、－ＣＯＮＨ－、－ＳＯ_２－、－Ｃ（ＣＦ_３）_２－、－Ｃ（ＣＨ_３）_２－、－ＣＨ_２－、－Ｏ－Ｃ_６Ｈ_４－Ｃ（ＣＨ_３）_２－Ｃ_６Ｈ_４－Ｏ－、－Ｏ－Ｃ_６Ｈ_４－Ｃ（ＣＦ_３）_２－Ｃ_６Ｈ_４－Ｏ－、－Ｏ－Ｃ_６Ｈ_４－ＳＯ_２－Ｃ_６Ｈ_４－Ｏ－、－Ｃ（ＣＨ_３）_２－Ｃ_６Ｈ_４－Ｃ（ＣＨ_３）_２－、－Ｏ－Ｃ_１０Ｈ_６－Ｏ－、－Ｏ－Ｃ_６Ｈ_４－Ｃ_６Ｈ_４－Ｏ－、及び－Ｏ－Ｃ_６Ｈ_４－Ｏ－で表される基よりなる群から選択される１種を示す。
Ｑの例示における、－Ｃ_６Ｈ_４－はフェニレン基であり、ｍ－フェニレン基、及びｐ－フェニレン基が好ましく、ｐ－フェニレン基がより好ましい。また、－Ｃ_１０Ｈ_６－は、ナフタレンジイル基であり、ナフタレン－１，２－ジイル基、ナフタレン－１，４－ジイル基、ナフタレン－２，３－ジイル基、ナフタレン－２，６－ジイル基、及びナフタレン－２，７－ジイル基が好ましく、ナフタレン－１，４－ジイル基、及びナフタレン－２，６－ジイル基がより好ましい。） When A ² is an organic group containing an aromatic ring, from the viewpoint of heat resistance of the cured product formed using the resin composition, the organic group is a group represented by the following formulas (21) to (24). It is preferable that at least one of the above is used.

(In formulas (21) to (24), R ¹¹¹ is a group consisting of a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, and a halogenated alkyl group having 1 to 4 carbon atoms. In the formula (24), Q is a 9,9'-fluorenylidene group, or the formula: -C ₆ H ₄ -, -CONH-C ₆ H ₄ -NHCO-, -NHCO -C ₆ H ₄ -CONH-, -O-C ₆ H ₄ -CO-C ₆ H ₄ -O-, -OCO-C ₆ H ₄ -COO-, -OCO-C ₆ H ₄ -C ₆ H ₄ -COO-, -OCO-, -O-, -S-, -CO-, -CONH-, -SO ₂ -, -C(CF ₃ ) ₂ -, -C(CH ₃ ) ₂ -, -CH ₂ -, -O-C ₆ H ₄ -C(CH ₃ ) ₂ -C ₆ H ₄ -O-, -O-C ₆ H ₄ -C(CF ₃ ) ₂ -C ₆ H ₄ -O-, -O -C ₆ H ₄ -SO ₂ -C ₆ H ₄ -O-, -C(CH ₃ ) ₂ -C ₆ H ₄ -C(CH ₃ ) ₂ -, -O-C ₁₀ H ₆ -O-, - It represents one selected from the group consisting of groups represented by O-C ₆ H ₄ -C ₆ H ₄ -O- and -O-C ₆ H ₄ -O-.
In the example of Q, -C ₆ H ₄ - is a phenylene group, preferably m-phenylene group and p-phenylene group, more preferably p-phenylene group. In addition, -C ₁₀ H ₆ - is a naphthalene diyl group, and naphthalene-1,2-diyl group, naphthalene-1,4-diyl group, naphthalene-2,3-diyl group, naphthalene-2,6-diyl group and a naphthalene-2,7-diyl group are preferred, and a naphthalene-1,4-diyl group and a naphthalene-2,6-diyl group are more preferred. )

From the viewpoint of heat resistance of the polyimide resin formed, R ¹¹¹ in formulas (21) to (24) is more preferably a hydrogen atom, a hydroxyl group, a fluorine atom, a methyl group, an ethyl group, or a trifluoromethyl group, A hydrogen atom, a hydroxyl group, or a trifluoromethyl group is particularly preferred.

Q in formula (24) is 9,9'-fluorenylidene group, -O-C ₆ H ₄ -O-, -C(CF ₃ ) ₂ -, from the viewpoint of heat resistance of the polyimide resin formed. -O-, -C(CH ₃ ) ₂ -, -CH ₂ -, or -O-C ₆ H ₄ -C(CH ₃ ) ₂ -C ₆ H ₄ -O-, -CONH- are preferred, and -O -C ₆ H ₄ -O-, -C(CF ₃ ) ₂ - or -O- is particularly preferred.

When using an aromatic diamine as the diamine compound represented by formula (a3-1), for example, the aromatic diamines shown below can be suitably used.
That is, aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl ) biphenyl, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4' -diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4 -aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4 -(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9 ,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, and 4,4'-[1,4-phenylenebis(1-methylethane-1,1 -diyl)] dianiline and the like. Among these, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenyl ether, and 4,4'-diaminobenzanilide are preferred in terms of price, availability, and the like.

Further, as A ² , a silicon atom-containing group which may have a chain aliphatic group and/or an aromatic ring can be employed. As such a silicon atom-containing group, the groups shown below can typically be used.

（式（Ｓｉ－１）中、Ｒ^１１２及びＲ^１１３は、それぞれ独立に、単結合又はメチレン基、炭素原子数２以上２０以下のアルキレン基、炭素原子数３以上２０以下のシクロアルキレン基、又は炭素原子数６以上２０以下のアリーレン基等であり、Ｒ^１１４、Ｒ^１１５、Ｒ^１１６、及びＲ^１１７は、それぞれ独立に、炭素原子数１以上２０以下のアルキル基、炭素原子数３以上２０以下のシクロアルキル基、炭素原子数６以上２０以下のアリール基、炭素原子数２０以下のアミノ基を含む基、－Ｏ－Ｒ^１１８で表される基（Ｒ^１１８は炭素原子数１以上２０以下の炭化水素基）、炭素原子数２以上２０以下の１以上のエポキシ基を含む有機基であり、ｌは、３以上５０以下の整数である。） Furthermore, from the viewpoint of further improving the mechanical properties of the resulting polyimide resin, a group represented by the following formula (Si-1) can also be preferably used as A ² .

(In formula (Si-1), R ¹¹² and R ¹¹³ are each independently a single bond or a methylene group, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or An arylene group having 6 to 20 carbon atoms, etc., and R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ are each independently an alkyl group having 1 to 20 carbon atoms, and 3 to 20 carbon atoms. A group containing a cycloalkyl group having 6 to 20 carbon atoms, an amino group having 20 or less carbon atoms, a group represented by -O-R ¹¹⁸ (R ¹¹⁸ is a group containing 1 to 20 carbon atoms) (hydrocarbon group), an organic group containing one or more epoxy groups having 2 or more and 20 or less carbon atoms, and l is an integer of 3 or more and 50 or less.)

The alkylene group having 2 to 20 carbon atoms in R ¹¹² and R ¹¹³ in formula (Si-1) is preferably an alkylene group having 2 to 10 carbon atoms from the viewpoint of heat resistance and residual stress, and dimethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, etc.

The cycloalkylene group having 3 to 20 carbon atoms in R ¹¹² and R ¹¹³ in formula (Si-1) is preferably a cycloalkylene group having 3 to 10 carbon atoms from the viewpoint of heat resistance and residual stress. , cyclobutylene group, cyclopentylene group, cyclohexylene group, cycloheptylene group, etc.
The arylene group having 6 to 20 carbon atoms in R ¹¹² and R ¹¹³ in formula (Si-1) is preferably an aromatic group having 6 to 20 carbon atoms from the viewpoint of heat resistance and residual stress. Examples include phenylene group and naphthylene group.

The alkyl group having 1 to 20 carbon atoms in R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ in formula (Si-1) is an alkyl group having 1 to 20 carbon atoms, from the viewpoint of heat resistance and residual stress. Alkyl groups are preferred, and specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl groups.
The cycloalkyl group having 3 to 20 carbon atoms in R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ in formula (Si-1) has 3 to 10 carbon atoms from the viewpoint of heat resistance and residual stress. A cycloalkyl group is preferred, and specific examples include a cyclopentyl group and a cyclohexyl group.
The aryl group having 6 to 20 carbon atoms in R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ in formula (Si-1) is an aryl group having 6 to 12 carbon atoms from the viewpoint of heat resistance and residual stress. Aryl groups are preferred, and specific examples include phenyl, tolyl, and naphthyl groups.
Examples of the group containing an amino group having 20 or less carbon atoms in R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ in formula (Si-1) include an amino group, a substituted amino group (for example, bis(trialkylsilyl) ) amino group), etc.
The group represented by -OR ¹¹⁸ in R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ in formula (Si-1) includes a methoxy group, an ethoxy group, a propoxy group, an isopropyloxy group, a butoxy group, Examples include phenoxy group, tolyloxy group, naphthyloxy group, propenyloxy group (eg, allyloxy group), and cyclohexyloxy group.
Among them, R ¹¹⁴ , R ¹¹⁵ , R ¹¹⁶ , and R ¹¹⁷ are preferably a methyl group, an ethyl group, a propyl group, or a phenyl group.

The group represented by formula (Si-1) can be derived by allowing a silicon-containing compound having amino groups at both ends to act on an acid anhydride. Specific examples of such silicon-containing compounds include both terminally amino-modified methylphenyl silicones (for example, X-22-1660B-3 (number average molecular weight approximately 4,400) and X-22-9409 (manufactured by Shin-Etsu Chemical Co., Ltd.)). (number average molecular weight approximately 1,300)), dimethyl silicone modified with amino at both ends (for example, Shin-Etsu Chemical Co., Ltd., X-22-161A (number average molecular weight approximately 1,600), X-22-161B (number average molecular weight 3, 000) and KF8012 (number average molecular weight of approximately 4,400); BY16-835U manufactured by Dow Corning Toray (number average molecular weight of approximately 900); and Silaplane FM3311 manufactured by JNC (number average molecular weight of approximately 1000). It will be done.

[Method for producing polyamic acid (A)]
The polyamic acid (A) having the structural unit represented by the formula (a1) typically comprises a tetracarboxylic dianhydride represented by the above formula (a1-1) and the above formula (a3- A polymer obtained by reacting a diamine compound represented by 1) in a solvent, and a polymer obtained by using one or more types of diamine compound and/or tetracarboxylic dianhydride, respectively. Good too. For example, it may be a polymer obtained by polycondensing a diamine compound and a mixture containing two or more types of tetracarboxylic dianhydrides. Moreover, polyamic acid (A) can be used individually or in mixture of 2 or more types.

The amount of the tetracarboxylic dianhydride and diamine compound to be used when synthesizing polyamic acid (A) is not particularly limited, but the amount of the diamine compound used is 0.50 mol or more per 1 mol of the tetracarboxylic dianhydride. It is preferable to use 0.50 mol or less, more preferably 0.60 mol or more and 1.30 mol or less, particularly preferably 0.70 mol or more and 1.20 mol or less.
Further, the weight average molecular weight of the obtained polyamic acid (A) may be appropriately set according to its use, but is, for example, 5,000 or more, preferably 7,500 or more, and more preferably 10,000 or more. On the other hand, the weight average molecular weight of the obtained polyamic acid (A) is, for example, 100,000 or less, preferably 80,000 or less, and more preferably 75,000 or less.
This weight average molecular weight may be set to the above-mentioned value by adjusting the blending amounts of the tetracarboxylic dianhydride and diamine compound, and reaction conditions such as the solvent and reaction temperature.

The reaction between a tetracarboxylic dianhydride and a diamine compound is usually carried out in an organic solvent. The organic solvent used in the reaction between the tetracarboxylic dianhydride and the diamine compound is an organic solvent that can dissolve the tetracarboxylic dianhydride and the diamine compound and does not react with the tetracarboxylic dianhydride and the diamine compound. There are no particular limitations as long as it is a solvent. Organic solvents can be used alone or in combination of two or more.

Examples of organic solvents used for the reaction between tetracarboxylic dianhydride and diamine compound include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, Nitrogen-containing polar solvents such as N,N-diethylformamide, N-methylcaprolactam, and N,N,N',N'-tetramethylurea; dimethyl sulfoxide; acetonitrile; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, and tetrahydrofuran, etc. Examples include ethers.

Among these organic solvents, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N , N-diethylformamide, N-methylcaprolactam, and N,N,N',N'-tetramethylurea are preferred.

The temperature at which the tetracarboxylic dianhydride and the diamine compound are reacted is not particularly limited as long as the reaction proceeds well. Typically, the reaction temperature between the tetracarboxylic dianhydride and the diamine compound is preferably -5°C or higher and 150°C or lower, more preferably 0°C or higher and 120°C or lower, particularly preferably 0°C or higher and 70°C or lower. . The time for reacting the tetracarboxylic dianhydride and the diamine compound varies depending on the reaction temperature, but typically, it is preferably 1 hour or more and 50 hours or less, more preferably 2 hours or more and 40 hours or less, and 5 hours. The time period of 30 hours or less is particularly preferable.

By the method explained above, a solution containing polyamic acid (A) can be obtained.
The solution containing the polyamic acid (A) obtained as described above can be used as it is for preparing a varnish composition, or the solution containing the polyamic acid (A) can be used as it is to prepare a varnish composition. A paste or solid of polyamic acid obtained by removing at least a portion of the solvent from a solution of acid (A) can also be used for preparing the varnish composition.

The content of the polyamic acid (A) in the varnish composition is appropriately determined by taking into consideration the coatability of the varnish composition, the solubility of the polyamic acid (A) in the solvent (S), and the like. Typically, the content of polyamic acid (A) in the varnish composition is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 20% by mass or less, based on the mass of the varnish composition. , more preferably 13% by mass or more and 17% by mass or less.

<Solvent (S)>
The solvent (S) includes a nitrogen-containing organic solvent (S-I) and a sulfur-containing organic solvent (S-II).
As mentioned above, the varnish composition contains a combination of the nitrogen-containing organic solvent (S-I) and the sulfur-containing organic solvent (S-II), so that the polyamic acid (A) is contained in the varnish composition. It dissolves well and suppresses odor generation during storage and polyimide resin production.

（式（Ｓ１）中、Ｒ^Ｓ１及びＲ^Ｓ２は、それぞれ独立に炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３は、水素原子、又は下記式（Ｓ１－１）若しくは下記式（Ｓ１－２）：

で表される基であり、Ｒ^Ｓ４は、水素原子又は水酸基であり、Ｒ^Ｓ５及びＲ^Ｓ６は、それぞれ独立に、水素原子、炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ７及びＲ^Ｓ８は、それぞれ独立に水素原子、又は炭素原子数１以上３以下のアルキル基であり、Ｒ^Ｓ３が式（Ｓ１－１）で表される基である場合、Ｒ^Ｓ２及びＲ^Ｓ３は、互いに結合して環を形成してもよい。）
で表される含窒素化合物である。 (Nitrogen-containing organic solvent (SI))
The nitrogen-containing organic solvent (SI) has the following formula (S1):

(In formula (S1), R ^S1 and R ^S2 are each independently an alkyl group having 1 to 3 carbon atoms, and R ^S3 is a hydrogen atom, or the following formula (S1-1) or the following formula (S1 -2):

R ^S4 is a hydrogen atom or a hydroxyl group, R ^S5 and R ^S6 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ^S7 and R ^S8 is each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when R ^S3 is a group represented by formula (S1-1), R ^S2 and R ^S3 are bonded to each other. may be used to form a ring. )
It is a nitrogen-containing compound represented by

Among the nitrogen-containing compounds represented by formula (S1), specific examples when R ^S3 is a hydrogen atom or a group represented by formula (S1-1) include N,N-dimethylformamide, N , N-dimethylacetamide, N,N,2-trimethylpropionamide, N-ethyl,N,2-dimethylpropionamide, N,N-diethyl-2-methylpropionamide, N,N,2-trimethyl-2- Examples include hydroxypropionamide, N-ethyl-N,2-dimethyl-2-hydroxypropionamide, and N,N-diethyl-2-hydroxy-2-methylpropionamide.

In the nitrogen-containing compound represented by formula (S1), when R ^S3 is a group represented by formula (S1-1) and R ^S2 and R ^S3 are bonded to each other to form a ring, Specific examples include N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone.

Among the nitrogen-containing compounds represented by formula (S1), specific examples when R ^S3 is a group represented by formula (S1-2) include N,N,N',N'-tetramethylurea. , N,N,N',N'-tetraethylurea and the like.

Among the above examples of nitrogen-containing compounds represented by formula (S1), particularly preferred compounds include N,N-dimethylformamide, N,N-dimethylacetamide, N,N,2-trimethylpropionamide, and N. , N,N',N'-tetramethylurea. Among these, N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea are preferred. The boiling point of N,N,2-trimethylpropionamide under atmospheric pressure is 175°C, and the boiling point of N,N,N',N'-tetramethylurea is 177°C under atmospheric pressure. Thus, N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea have relatively low boiling points among organic solvents (SI).
Therefore, when using a varnish composition containing a solvent (S) containing at least one selected from N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea, When forming a polyimide resin, the solvent (S) is unlikely to remain in the polyimide resin produced by heating, and the mechanical properties of the resulting polyimide resin are unlikely to deteriorate.

Furthermore, N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea are classified as SVHC (substances of concern for toxicity) under the REACH regulation in the EU (European Union). It is also useful in that it is a substance with low toxicity, as it is not designated as a substance of very high concern.

(Sulfur-containing organic solvent (S-II))
The sulfur-containing organic solvent (S-II) has the following formula (S2):
R ^S9 -S(=O) ₂ -R ^S10 ...(S2)
(In formula (S2), R ^S9 and R ^S10 are each independently an organic group that may contain one or more hetero atoms selected from the group consisting of an oxygen atom, a nitrogen atom, and a halogen atom. , R ^S9 and R ^S10 may be combined with each other to form a ring.)
It is a sulfur-containing compound represented by By dissolving the sulfur-containing organic solvent (S-II) in the solvent (S), it is easy to form a polyimide resin with a highly smooth surface while suppressing the generation of odor in the varnish composition.

The organic groups as R ^S9 and R ^S10 may contain one or more types of hetero atoms selected from the group consisting of oxygen atoms, nitrogen atoms, and halogen atoms. It is preferable that the carbon atom in such an organic group and the sulfur atom in -S(=O) ₂ - bond.

R ^S9 and R ^S10 may be combined with each other to form a ring. R ^S9 and R ^S10 are preferably bonded to each other to form a ring, since it is easier to suppress the generation of odor in the varnish.

Suitable examples of organic groups as R ^S9 and R ^S10 include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, aliphatic hydrocarbon groups substituted with alkoxy groups, and aromatic hydrocarbon groups substituted with alkoxy groups. group, a halogenated aliphatic hydrocarbon group, a halogenated aromatic hydrocarbon group, and the like.
The number of carbon atoms in the organic group as R ^S9 and R ^S10 is preferably 1 or more and 10 or less, more preferably 1 or more and 6 or less, and even more preferably 1 or more and 4 or less.
Specific examples of organic groups as R ^S9 and R ^S10 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group. group, n-hexyl group, methoxymethyl group, ethoxymethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 3-methoxypropyl group, 3-ethoxypropyl group, chloromethyl group, dichloromethyl group, trichloromethyl group , bromomethyl group, sub-bromomethyl group, tribromomethyl group, phenyl group, naphthalen-1-yl group, naphthalen-2-yl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 2- Examples include chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2-bromophenyl group, 3-bromophenyl group, and 4-bromophenyl group.
As the organic group as R ^S9 and R ^S10 , an alkyl group having 1 or more and 6 or less carbon atoms is preferable.

Specific examples of the sulfur-containing compound represented by formula (S2) include dimethylsulfone, diethylsulfone, methylethylsulfone, methylisopropylsulfone, ethylisopropylsulfone, divinylsulfone, sulfolane, 3-methylsulfolane, and 1,4- Examples include butane sultone. Among these, sulfolane and 3-methylsulfolane are preferred because they easily suppress the generation of odor in the varnish.

(Other solvents (S-III))
The varnish composition may contain other solvents (S-III) other than the above-mentioned nitrogen-containing organic solvent (S-I) and sulfur-containing organic solvent (S-II) as long as the object of the present invention is not impaired. You can stay there.
However, from the viewpoint of odor control, the varnish composition preferably does not substantially contain a mercapto compound, a sulfide compound, or a solvent that can generate a mercapto compound or a sulfide compound by decomposition as other solvent (S-III). . "Substantially free" means that the content in the solvent (S) is 0.1% by mass or less. The content of the solvent, which is unfavorable in terms of odor suppression, is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, based on the mass of the solvent (S).

Examples of solvents that can generate mercapto compounds and sulfide compounds include sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide.

Preferred specific examples of other solvents (S-III) include water; alcoholic solvents such as polyethylene glycol, ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; acetonitrile; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, and ethers such as tetrahydrofuran.

The content of the nitrogen-containing organic solvent (S-I) and the sulfur-containing organic solvent (S-II) in the solvent (S) is preferably 80% by mass or more, and 90% by mass or more in terms of the solubility of the polyamic acid (A). It is more preferably at least 95% by mass, even more preferably at least 95% by mass, and most preferably 100% by mass.
The ratio of the mass of the sulfur-containing organic solvent (S-II) to the mass of the solvent (S) because it is easy to achieve both the solubility of the polyamic acid (A) and the suppression of odor generation in the varnish composition at a high level. is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 15% by mass or less.

<Thermal base generator (B)>
In order to facilitate the production of polyamide resin from polyamic acid (A) by firing, the varnish composition preferably contains a thermal base generator (B) that generates a basic nitrogen-containing heterocyclic compound by heating.

The basic nitrogen-containing heterocyclic compound generated by the thermal base generator (B) may be an aliphatic cyclic compound or an aromatic compound. When the basic nitrogen-containing heterocyclic compound is a compound in which two or more monocycles are condensed, the two or more monocycles may consist of only an aliphatic ring, or only an aromatic ring. It may consist of a combination of a group ring and an aromatic ring.

Examples of the basic nitrogen-containing heterocyclic compound generated by the thermal base generator (B) include pyrrolidine, pyrazolidine, imidazolidine, triazolidine, tetrazolidine, pyrroline, pyrazoline, imidazoline, triazoline, tetrazoline, pyrrole, pyrazole, imidazole, and triazole. Nitrogen-containing 5-membered ring compounds such as Examples include compounds condensed with cyclopentane, cyclohexane, benzene, etc.
When the basic nitrogen-containing heterocyclic compound has a substituent on the nitrogen-containing heterocycle, the substituent includes the same groups as R ¹ , R ² , and R ³ in formula (B1) described below. Can be mentioned.

（式（Ｂ１）中、Ｒ^１、Ｒ^２、及びＲ^３は、それぞれ独立に水素原子、ハロゲン原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホナト基、又は有機基である。）
で表されるイミダゾール化合物が好ましい。 The basic nitrogen-containing heterocyclic compound generated by the thermal base generator (B) component has the following formula (B1):

(In formula (B1), R ¹ , R ² , and R ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, (phosphonato group or organic group)
An imidazole compound represented by is preferred.

Examples of the organic group for R ¹ , R ² , and R ³ include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, an aralkyl group, and the like. This organic group may contain a bond or substituent other than a hydrocarbon group such as a hetero atom. Further, this organic group may be linear, branched, or cyclic. This organic group is usually monovalent, but when forming a cyclic structure, it can be a divalent or higher organic group.

R ¹ and R ² may be combined to form a cyclic structure, and may further include a heteroatom bond. Examples of the cyclic structure include a heterocycloalkyl group and a heteroaryl group, and may be a fused ring.

The bonds contained in the organic groups of R ¹ , R ² and R ³ are not particularly limited as long as the effects of the present invention are not impaired. The organic group may include a bond containing a heteroatom such as an oxygen atom, a nitrogen atom, or a silicon atom. Specific examples of bonds containing heteroatoms include ether bonds, carbonyl bonds, thiocarbonyl bonds, ester bonds, amide bonds, urethane bonds, and imino bonds (-N=C(-R)-, -C(=NR)- :R represents a hydrogen atom or an organic group), a carbonate bond, a sulfonyl bond, an azo bond, etc.

From the viewpoint of heat resistance of the imidazole compound, examples of the bond containing a heteroatom that the organic groups of R ¹ , R ² , and R ³ may include include an ether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, and an amide bond. , urethane bond, imino bond (-N=C(-R)-, -C(=NR)-: R represents a hydrogen atom or a monovalent organic group), carbonate bond, and sulfonyl bond.

When the organic groups of R ¹ , R ² , and R ³ are substituents other than hydrocarbon groups, R ¹ , R ² , and R ³ are not particularly limited as long as the effects of the present invention are not impaired. As mentioned above, specific examples of R ¹ , R ² and R ³ are a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, and a phosphonato group. The hydrogen atom included in the above substituent may be substituted with a hydrocarbon group. Moreover, the hydrocarbon group contained in the above-mentioned substituent may be linear, branched, or cyclic.

R ¹ , R ² , and R ³ include a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and a halogen. An atom is preferable, and a hydrogen atom is more preferable.

The thermal base generator (B) is not particularly limited as long as it is a compound that can generate a basic nitrogen-containing heterocyclic compound by heating. Regarding compounds that generate amines under the action of heat (thermal base generators), which have been conventionally blended into various compositions, it is possible to convert the skeleton derived from the amines generated during heating into the desired basic nitrogen-containing heterocyclic compound. By substituting the derived skeleton, a compound used as a thermal base generator (B) can be obtained.

（式（Ｂ２）中、Ｒ^１、Ｒ^２、及びＲ^３は、式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ１及びＲ^ｂ２は、それぞれ独立に水素原子、ハロゲン原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、又は有機基を示し、Ｒ^ｂ３、Ｒ^ｂ４、Ｒ^ｂ５、Ｒ^ｂ６、及びＲ^ｂ７は、それぞれ独立に水素原子、ハロゲン原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基を示し、Ｒ^ｂ３、Ｒ^ｂ４、Ｒ^ｂ５、Ｒ^ｂ６、及びＲ^ｂ７は、それらの２つ以上が結合して環状構造を形成していてもよく、ヘテロ原子の結合を含んでいてもよい。）
で表される化合物が挙げられる。 A suitable thermal base generator (B) has the following formula (B2):

(In formula (B2), R ¹ , R ² , and R ³ are the same as those in formula (B1), and R ^b1 and R ^b2 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, Represents a silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonato group, phosphino group, phosphinyl group, phosphono group, phosphonato group, or organic group, R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 is each independently a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, It represents an ammonio group or an organic group, and two or more of R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 may combine to form a cyclic structure, and a heteroatom bond may be formed. may be included.)
Examples include compounds represented by:

In formula (B2), R ¹ , R ² , and R ³ are the same as those described for formula (B1).

In formula (B2), R ^b1 and R ^b2 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group. , represents a phosphono group, a phosphonato group, or an organic group.

Examples of the organic group for R ^b1 and R ^b2 include the groups exemplified for R ¹ , R ² , and R ³ . This organic group may contain a heteroatom therein, as in the case of R ¹ , R ² , and R ³ . Further, this organic group may be linear, branched, or cyclic.

Among the above, R ^b1 and R ^b2 each independently include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 4 to 13 carbon atoms, and a cycloalkyl group having 4 to 13 carbon atoms. Alkenyl group, aryloxyalkyl group having 7 to 16 carbon atoms, aralkyl group having 7 to 20 carbon atoms, alkyl group having cyano group and having 2 to 11 carbon atoms, 1 or more carbon atoms having hydroxyl group Alkyl group having 10 or less carbon atoms, alkoxy group having 1 to 10 carbon atoms, amide group having 2 to 11 carbon atoms, acyl group having 1 to 10 carbon atoms, ester group having 2 to 11 carbon atoms ( -COOR, -OCOR: R represents a hydrocarbon group), an aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms substituted with an electron-donating group and/or an electron-withdrawing group , a benzyl group or a cyano group substituted with an electron-donating group and/or an electron-withdrawing group are preferable. More preferably, both R ^b1 and R ^b2 are hydrogen atoms, or R ^b1 is a methyl group and R ^b2 is a hydrogen atom.

In formula (B2), R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group. group, sulfino group, sulfo group, sulfonato group, phosphino group, phosphinyl group, phosphono group, phosphonato group, amino group, ammonio group, or organic group.

Examples of the organic groups for R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 include the groups exemplified for R ¹ , R ² , and R ³ . This organic group may contain a bond or substituent other than the hydrocarbon group, such as a hetero atom, in the organic group, as in the case of R ¹ , R ² , and R ³ . Further, this organic group may be linear, branched, or cyclic.

Two or more of R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 may be combined to form a cyclic structure. R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 may each contain a bond containing a hetero atom. Examples of the cyclic structure include a heterocycloalkyl group and a heteroaryl group, and may be a fused ring. For example, R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 are bonded together, and R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 are bonded to benzene. Ring atoms may be shared to form a condensed ring such as naphthalene, anthracene, phenanthrene, indene, etc. When a fused ring is formed, it is preferable because the absorption wavelength becomes longer.

Among the above, R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 each independently include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a cycloalkyl group having 4 to 13 carbon atoms. , a cycloalkenyl group having 4 to 13 carbon atoms, an aryloxyalkyl group having 7 to 16 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkyl group having 2 to 11 carbon atoms and having a cyano group. group, an alkyl group having 1 to 10 carbon atoms and having a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an amide group having 2 to 11 carbon atoms, an acyl group having 1 to 10 carbon atoms, carbon Ester group having 2 to 11 atoms, aryl group having 6 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms substituted with an electron donating group and/or electron withdrawing group, electron donating group And/or the electron-withdrawing group is preferably a substituted benzyl group, cyano group, or nitro group.

（式（Ｂ３）中、Ｒ^１、Ｒ^２、及びＲ^３は、式（Ｂ１）及び（Ｂ２）と同義である。Ｒ^ｂ１～Ｒ^ｂ６は式（Ｂ２）と同義である。Ｒ^ｂ８は、水素原子又は有機基を示す。Ｒ^ｂ３及びＲ^ｂ４が水酸基となることはない。Ｒ^ｂ３、Ｒ^ｂ４、Ｒ^ｂ５、及びＲ^ｂ６は、それらの２つ以上が結合して環状構造を形成していてもよく、ヘテロ原子の結合を含んでいてもよい。）
で表される化合物が好ましい。 Among the compounds represented by the above formula (B2), the following formula (B3):

(In formula (B3), R ¹ , R ² , and R ³ have the same meanings as formulas (B1) and (B2). R ^b1 to R ^b6 have the same meanings as formula (B2). ^{R b8} is Represents a hydrogen atom or an organic group. R ^b3 and R ^b4 cannot be a hydroxyl group. R ^b3 , R ^b4 , R ^b5 , and R ^b6 are two or more of them that are combined to form a cyclic structure. (It may contain a heteroatom bond.)
Compounds represented by are preferred.

Since the compound represented by formula (B3) has the substituent -O-R ^b8 , it has excellent solubility in the solvent (S).

In formula (B3), R ^b8 is a hydrogen atom or an organic group. When R ^b8 is an organic group, examples of the organic group include the groups exemplified for R ¹ , R ² , and R ³ . This organic group may contain a heteroatom within the organic group. Further, this organic group may be linear, branched, or cyclic. R ^b8 is preferably a hydrogen atom or an alkyl group having 1 or more and 12 or less carbon atoms, and more preferably a methyl group.

Specific examples of compounds particularly suitable as the thermal base generator (B) among the compounds represented by formula (B1) are shown below.

（式（Ｂ４）中、Ｒ^１、Ｒ^２、及びＲ^３は、式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ９は、水素原子又は１価の有機基を表し、Ｒ^ｂ１０は置換基を有してもよい芳香族基を表し、Ｒ^ｂ９は他方のＲ^ｂ９又はＲ^ｂ１０と結合して環状構造を形成してもよい。） Further, an imidazole compound represented by the following formula (B4) is also suitable as the thermal base generator (B).

(In formula (B4), R ¹ , R ² , and R ³ are the same as those in formula (B1), R ^b9 represents a hydrogen atom or a monovalent organic group, and R ^b10 represents a substituent. represents an optional aromatic group, and R ^b9 may combine with the other R ^b9 or R ^b10 to form a cyclic structure.)

In formula (B4), R ^b9 is a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, and may be, for example, an alkyl group that may have a substituent, an aromatic group that may have a substituent, or the like. When R ^b9 is an alkyl group, the alkyl group may have an ester bond or the like in the chain.

The alkyl group may be the same as, for example, R ^b11 in formula (B4a) described below. The number of carbon atoms in the alkyl group is preferably 1 or more and 40 or less, more preferably 1 or more and 30 or less, particularly preferably 1 or more and 20 or less, and most preferably 1 or more and 10 or less.
The substituent that the alkyl group may have may be the same as the substituent that the alkylene group that is R ^b11 in formula (B4a) described below may have, for example.

The aromatic group which may have a substituent is the same as R ^b10 in formula (B4a) described below, preferably an aryl group, and more preferably a phenyl group. The aromatic group which may have a substituent as R ^b9 may be the same as or different from R ^b10 .
In formula (B4), one R ^b9 is preferably a hydrogen atom, one R ^b9 is a hydrogen atom, and the other R ^b9 has an alkyl group that may have a substituent or a substituent. More preferably, it is an aromatic group.
In formula (B4), R ^b9 may combine with the other R ^b9 or R ^b10 to form a cyclic structure. For example, when at least one R ^b9 is an alkyl group that may have a substituent, R ^b9 may be combined with the other R ^b9 or R ^b10 to form a cyclic structure.

The imidazole compound represented by the formula (B4) may be a compound represented by the following formula (B4a).

（式（Ｂ４ａ）中、Ｒ^１、Ｒ^２、及びＲ^３は式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ１１は水素原子又はアルキル基であり、Ｒ^ｂ１０は置換基を有してもよい芳香族基であり、Ｒ^ｂ１２は置換基を有してもよいアルキレン基であり、Ｒ^ｂ１２はＲ^ｂ１０と結合して環状構造を形成してもよい。）

(In formula (B4a), R ¹ , R ² , and R ³ are the same as those in formula (B1), R ^b11 is a hydrogen atom or an alkyl group, and R ^b10 may have a substituent. It is an aromatic group, R ^b12 is an alkylene group which may have a substituent, and R ^b12 may be combined with R ^b10 to form a cyclic structure.)

In formula (B4a), R ^b11 is a hydrogen atom or an alkyl group. When R ^b11 is an alkyl group, the alkyl group may be a straight chain alkyl group or a branched chain alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less.

Specific examples of alkyl groups suitable as R ^b11 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, Isopentyl group, tert-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethyl-n-hexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, and n-icosyl group.

In formula (B4a), R ^b10 is an aromatic group that may have a substituent. The aromatic group which may have a substituent may be an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent.

The type of aromatic hydrocarbon group is not particularly limited as long as it does not impede the purpose of the present invention. The aromatic hydrocarbon group may be a monocyclic aromatic group, or may be a group formed by condensing two or more aromatic hydrocarbon groups, and may be a group formed by condensing two or more aromatic hydrocarbon groups. may be a group formed by bonding through a single bond. As the aromatic hydrocarbon group, a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a phenanthrenyl group are preferable.

The type of aromatic heterocyclic group is not particularly limited as long as it does not impede the purpose of the present invention. The aromatic heterocyclic group may be a monocyclic group or a polycyclic group. Preferred examples of the aromatic heterocyclic group include a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, an isoxazolyl group, an isothiazolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzimidazolyl group.

Examples of substituents that a phenyl group, a polycyclic aromatic hydrocarbon group, or an aromatic heterocyclic group may have include a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, and a sulfo group. , a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, and an organic group. When a phenyl group, a polycyclic aromatic hydrocarbon group, or an aromatic heterocyclic group has a plurality of substituents, the plurality of substituents may be the same or different.

When the substituent of the aromatic group is an organic group, examples of the organic group include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, an aralkyl group, and the like. This organic group may contain a bond or substituent other than a hydrocarbon group such as a hetero atom. Further, this organic group may be linear, branched, cyclic, or a combination of these structures. This organic group is usually monovalent, but when forming a cyclic structure, it can be a divalent or higher organic group.

When an aromatic group has substituents on adjacent carbon atoms, the two substituents bonded on adjacent carbon atoms may be bonded together to form a cyclic structure. Examples of the cyclic structure include aliphatic hydrocarbon rings and aliphatic rings containing heteroatoms.

When the substituent of the aromatic group is an organic group, the bonds contained in the organic group are not particularly limited as long as the effects of the present invention are not impaired, and the organic group may include oxygen atoms, nitrogen atoms, silicon atoms, etc. may contain a bond containing a heteroatom. Specific examples of bonds containing heteroatoms include ether bonds, carbonyl bonds, thiocarbonyl bonds, ester bonds, amide bonds, urethane bonds, and imino bonds (-N=C(-R)-, -C(=NR)- :R represents a hydrogen atom or an organic group), a carbonate bond, a sulfonyl bond, an azo bond, etc.

From the viewpoint of heat resistance of the imidazole compound represented by formula (B4) or formula (B4a), examples of the bond containing a heteroatom that the organic group may have include an ether bond, a carbonyl bond, a thiocarbonyl bond, and an ester bond. , amide bond, amino bond (-NR-: R represents a hydrogen atom or monovalent organic group) urethane bond, imino bond (-N=C(-R)-, -C(=NR)-: R is (representing a hydrogen atom or a monovalent organic group), a carbonate bond, and a sulfonyl bond are preferable.

When the organic group is a substituent other than a hydrocarbon group, the type of the substituent other than the hydrocarbon group is not particularly limited as long as it does not impede the object of the present invention. Specific examples of substituents other than hydrocarbon groups include halogen atoms, hydroxyl groups, mercapto groups, sulfide groups, cyano groups, isocyano groups, cyanato groups, isocyanato groups, thiocyanato groups, isothiocyanato groups, silyl groups, silanol groups, and alkoxy groups. , alkoxycarbonyl group, amino group, monoalkylamino group, dialkylaluminum group, monoarylamino group, diarylamino group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxylate group, acyl group, acyloxy group, sulfino group group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonato group, an alkyl ether group, an alkenyl ether group, an aryl ether group, and the like. The hydrogen atom included in the above substituent may be substituted with a hydrocarbon group. Moreover, the hydrocarbon group contained in the above-mentioned substituent may be linear, branched, or cyclic.

The substituents of the phenyl group, polycyclic aromatic hydrocarbon group, or aromatic heterocyclic group include an alkyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, and 1 carbon atom. Preferred are an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, an arylamino group having 1 to 12 carbon atoms, and a halogen atom.

As R ^b10 , an imidazole compound represented by formula (B4) or formula (B4a) can be synthesized cheaply and easily, and imidazole compounds have good solubility in water and organic solvents, so R b10 has a substituent, respectively. A phenyl group, a furyl group, and a thienyl group are preferred.

In formula (B4a), R ^b12 is an alkylene group that may have a substituent. The substituent that the alkylene group may have is not particularly limited as long as it does not impede the object of the present invention. Specific examples of substituents that the alkylene group may have include a hydroxyl group, an alkoxy group, an amino group, a cyano group, and a halogen atom. The alkylene group may be a straight chain alkylene group or a branched chain alkylene group, and a straight chain alkylene group is preferred. The number of carbon atoms in the alkylene group is not particularly limited, and is preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, and particularly preferably 1 or more and 5 or less. Note that the number of carbon atoms in the alkylene group does not include carbon atoms in substituents bonded to the alkylene group.

The alkoxy group as a substituent bonded to the alkylene group may be a straight chain alkoxy group or a branched chain alkoxy group. The number of carbon atoms in the alkoxy group as a substituent is not particularly limited, and is preferably 1 or more and 10 or less, more preferably 1 or more and 6 or less, and particularly preferably 1 or more and 3 or less.

The amino group as a substituent bonded to the alkylene group may be a monoalkylamino group or a dialkylamino group. The alkyl group contained in the monoalkylamino group or dialkylamino group may be a straight-chain alkyl group or a branched-chain alkyl group. The number of carbon atoms in the alkyl group contained in the monoalkylamino group or dialkylamino group is not particularly limited, and is preferably 1 or more and 10 or less, more preferably 1 or more and 6 or less, and particularly preferably 1 or more and 3 or less.

Specific examples of alkylene groups suitable as R ^b12 include methylene group, ethane-1,2-diyl group, n-propane-1,3-diyl group, n-propane-2,2-diyl group, n-butane group. -1,4-diyl group, n-pentane-1,5-diyl group, n-hexane-1,6-diyl group, n-heptane-1,7-diyl group, n-octane-1,8-diyl group group, n-nonane-1,9-diyl group, n-decane-1,10-diyl group, n-undecane-1,11-diyl group, n-dodecane-1,12-diyl group, n-tridecane- 1,13-diyl group, n-tetradecane-1,14-diyl group, n-pentadecane-1,15-diyl group, n-hexadecane-1,16-diyl group, n-heptadecane-1,17-diyl group , n-octadecane-1,18-diyl group, n-nonadecane-1,19-diyl group, and n-icosane-1,20-diyl group.

Among the imidazole compounds represented by the above formula (B4), the compound represented by the following formula (B4-1a) is preferred because it can be synthesized inexpensively and easily.

（式（Ｂ４－１ａ）中、Ｒ^１、Ｒ^２、及び^Ｒ３は、式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ９は、式（Ｂ４）と同様であり、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７は、それぞれ独立に、水素原子、ハロゲン原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基である。Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７のうち少なくとも２つが結合して環状構造を形成してもよい。Ｒ^ｂ９はＲ^ｂ１５と結合して環状構造を形成してもよい。）
なお、式（Ｂ４－１ａ）において、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７は、全て水素原子であってもよい。また、式（Ｂ４－１）で表される化合物の溶媒（Ｓ）への溶解性の点で、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７のうちの少なくとも１つが水素原子以外の基であるのが好ましい。

(In formula (B4-1a), R ¹ , R ² , and ^R3 are the same as those in formula (B1), R ^b9 is the same as in formula (B4), and R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, and a phosphono group. group, phosphonato group, amino group, ammonio group, or organic group.At least two of R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 may be bonded to form a cyclic structure. R ^b9 may combine with R ^b15 to form a cyclic structure.)
Note that in formula (B4-1a), R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 may all be hydrogen atoms. In addition, in terms of the solubility of the compound represented by formula (B4-1) in the solvent (S), at least one of R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 is other than a hydrogen atom. It is preferable that it is a group of

R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 are the same as those in formula (B4-1) described below. In formula (B4-1a), R ^b9 may combine with R ^b15 to form a cyclic structure. For example, when R ^b9 is an alkyl group that may have a substituent, R ^b9 may be combined with R ^b15 to form a cyclic structure.

Among the imidazole compounds represented by the above formula (B4a) or formula (B4-1a), the following formula (B4-1) is inexpensive and easily synthesized, and has excellent solubility in water and organic solvents. A compound represented by formula (B4-1) is preferred, and a compound represented by formula (B4-1) in which R ^b12 is a methylene group is more preferred.

（式（Ｂ４－１）中、Ｒ^１、Ｒ^２、及び^Ｒ３は式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ１１、及びＲ^ｂ１２は、式（Ｂ４ａ）におけるこれらと同様であり、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７は、それぞれ独立に、水素原子、ハロゲン原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基である。Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７のうち少なくとも２つが結合して環状構造を形成してもよい。Ｒ^ｂ１２はＲ^ｂ１５と結合して環状構造を形成してもよい。）
なお、式（Ｂ４－１）において、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７は、全て水素原子であってもよい。また、式（Ｂ４－１）で表される化合物の溶媒（Ｓ）への溶解性の点で、Ｒ^ｂ１３、Ｒ^ｂ１４、Ｒ^ｂ１５、Ｒ^ｂ１６、及びＲ^ｂ１７のうちの少なくとも１つが水素原子以外の基であるのが好ましい。

(In formula (B4-1), R ¹ , R ² , and ^R3 are the same as those in formula (B1), R ^b11 and R ^b12 are the same as these in formula (B4a), and R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, and a phosphino group. , a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, or an organic group.At least two of R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 are bonded to form a cyclic structure. (R ^b12 may combine with R ^b15 to form a cyclic structure.)
Note that in formula (B4-1), R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 may all be hydrogen atoms. In addition, in terms of the solubility of the compound represented by formula (B4-1) in the solvent (S), at least one of R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 is other than a hydrogen atom. It is preferable that it is a group of

When R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 are organic groups, the organic group is the same as the organic group that R ^b10 in formula (B4a) has as a substituent. R ^b13 , R ^b14 , R ^b15 , and R ^b16 are preferably hydrogen atoms from the viewpoint of solubility of the imidazole compound in the solvent (S).

Among them, at least one of R ^b13 , R ^b14 , R ^b15 , R ^b16 , and R ^b17 is preferably the following substituent, and it is particularly preferable that R ^b17 is the following substituent. When R ^b17 is the following substituent, R ^b13 , R ^b14 , R ^b15 , and R ^b16 are preferably hydrogen atoms.
-OR ^b18
(R ^b18 is a hydrogen atom or an organic group.)

When R ^b18 is an organic group, the organic group is the same as the organic group that R ^b10 in formula (B4a) has as a substituent. R ^b18 is preferably an alkyl group, more preferably an alkyl group having 1 to 8 carbon atoms, particularly preferably an alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

（式（Ｂ４－１－１）において、Ｒ^１、Ｒ^２、及び^Ｒ３は式（Ｂ１）におけるこれらと同様であり、Ｒ^ｂ１１は、式（Ｂ４ａ）と同様であり、Ｒ^ｂ１９、Ｒ^ｂ２０、Ｒ^ｂ２１、Ｒ^ｂ２２、及びＲ^ｂ２３は、それぞれ独立に、水素原子、水酸基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基である。ただし、Ｒ^ｂ１９、Ｒ^ｂ２０、Ｒ^ｂ２１、Ｒ^ｂ２２、及びＲ^ｂ２３のうち少なくとも１つは水素原子以外の基である。） Among the compounds represented by the above formula (B4-1), the compounds represented by the following formula (B4-1-1) are preferred.

(In formula (B4-1-1), R ¹ , R ² , and ^R3 are the same as those in formula (B1), R ^b11 is the same as in formula (B4a), and R ^b19 , R ^b20 , R ^b21 , R ^b22 , and R ^b23 each independently represent a hydrogen atom, a hydroxyl group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, A phosphonato group, an amino group, an ammonio group, or an organic group.However, at least one of R ^b19 , R ^b20 , R ^b21 , R ^b22 , and R ^b23 is a group other than a hydrogen atom.)

Among the compounds represented by formula (B4-1-1), at least one of R ^b19 , R ^b20 , R ^b21 , R ^b22 , and R ^b23 is a group represented by the above-mentioned -O-R ^b18 . It is preferable that R ^b23 be a group represented by -O-R ^b18 . When R ^b23 is a group represented by -O-R ^b18 , R ^b19 , R ^b20 , R ^b21 and R ^b22 are preferably hydrogen atoms.

Preferred specific examples of the imidazole compound represented by formula (B4) or formula (B4a) include the following compounds.

The content of the thermal base generator (B) in the varnish composition is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, based on the mass of the varnish composition. By using the thermal base generator (B) in an amount within this range, the polyamide resin from the polyamic acid (A) can be produced without excessive volatilization or sublimation of the thermal decomposition products of the thermal base generator (B). production can be effectively promoted.

<Other ingredients>
The varnish composition may contain various additives as necessary. Examples of additives include colorants, dispersants, sensitizers, adhesion promoters, antioxidants, ultraviolet absorbers, anti-aggregation agents, antifoaming agents, surfactants, and the like. Further, the varnish composition may contain various fillers or reinforcing materials as necessary.
The amounts of various additives used are not particularly limited as long as they do not impede the purpose of the present invention. For example, it may be adjusted as appropriate within the range of 0.001% by mass or more and 60% by mass or less, preferably 0.05% by mass or more and 5% by mass or less, based on the mass of the solid content of the varnish composition.
The amount of filler or reinforcing material used is not particularly limited as long as it does not impede the purpose of the present invention. Typically, the amount of the filler or reinforcing material used is preferably 1% by mass or more and 300% by mass or less, more preferably 5% by mass or more and 200% by mass or more, and 10% by mass or more, based on the mass of the polyamic acid (A). More preferably, the content is from % by mass to 100% by mass.

As mentioned above, according to the above varnish composition, the generation of odor can be suppressed during storage of the varnish composition or during production of polyimide resin using the varnish composition.
Specifically, mass spectrometry was performed at a holding temperature of 300°C on the gas generated when a sample of the varnish composition was heated from 30°C to 550°C at a heating rate of 10°C/min in a helium atmosphere. In this case, the ratio of the peak area of the fragment derived from the organic sulfide compound to TICC, which is the sum of all intensities from the start m/z to the end m/z of the obtained spectrum, is 0.45 area%. It is preferably less than 0.40 area %, more preferably 0.30 area % or less, and even more preferably 0.30 area % or less.
The organic sulfide compound that may be generated when the varnish composition is heated can be determined from the compound contained in the solvent (S) and the chemical structure of the polyamic acid.
Further, the holding temperature is the temperature of the gas flow path from the place where gas is generated from the sample by heating to the analysis section of the mass spectrometer.
Note that the holding temperature may be a set value in the mass spectrometer, and the holding temperature is not strictly required to be 300°C. For example, the holding temperature may vary within a range of about 280°C to 320°C.

≪Production method of polyimide resin≫
A molding step of molding the varnish composition described above,
A polyimide resin can be manufactured by a method including an imidization step of heating and imidizing a molded varnish composition.

When molding the varnish composition, the shape of the molded varnish composition is not particularly limited. The method of molding the varnish composition is not particularly limited. Examples include a method of injecting the varnish composition into a mold of a desired shape, a method of filling the varnish composition into a mold using a squeegee, and a method of applying the varnish composition onto a base material. It will be done.
Among these methods, there is a method of applying a varnish composition onto a substrate because there is a large demand for polyimide resin films and it is easy to remove the solvent (S) from the varnish composition during polyimide resin production. is preferred.

The temperature at which the varnish composition is heated is not particularly limited as long as a polyimide resin with desired performance can be obtained. The temperature at which the polyamic acid is heated is preferably 120°C or more and 350°C or less, more preferably 150°C or more and 350°C or less. By heating the varnish composition at a temperature in such a range, it is possible to remove the solvent (S) and generate the polyimide resin while suppressing thermal deterioration and thermal decomposition of the polyimide resin to be generated.

According to the method for producing polyimide resin described above, polyimide resin can be produced satisfactorily while suppressing the generation of odor.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited to these Examples.

[Example 1, Example 2, and Comparative Example 1]
Polyamic acid is dissolved in a mixed solvent consisting of 90% by mass of the nitrogen-containing organic solvent listed in Table 1 below and 10% by mass of the sulfur-containing organic solvent listed in Table 1 below so that the solid content concentration is 15% by mass. In this way, varnish compositions of Example 1, Example 2, and Comparative Example 1 were obtained.
As the polyamic acid, aromatic diamine (4,4'-diaminobenzanilide (DABAN)) and tetracarboxylic dianhydride of the following formula are combined with N,N,N',N'-tetramethylurea (TMU ) in a nitrogen atmosphere at room temperature (25° C.) for 12 hours and a polyamic acid obtained was used. DABAN was used in an approximately equal molar amount to the tetracarboxylic dianhydride of the following formula.

A sample of the obtained varnish composition was subjected to differential thermal spectrometry-mass spectrometry (TG-DSC-MS). Specifically, after the varnish composition was placed on a sample holder in an analyzer, the sample was heated from 30°C to 550°C at a heating rate of 10°C/min in a helium atmosphere. The gas generated at that time was subjected to mass spectrometry at a holding temperature of 300°C to obtain an MS spectrum. The ratio of the peak area of the fragment derived from the organic sulfide compound, which is the odor-causing substance, to the TICC, which is the sum of all intensities from the start m/z to the end m/z of the obtained spectrum, was determined. Table 1 shows the calculated peak area ratios of fragments derived from organic sulfide compounds.

According to Table 1, the varnish composition of Example 1 and the varnish composition of Example 2, which contain sulfolane corresponding to the compound represented by formula (S2) or 3-methylsulfolane as a sulfur-containing organic solvent. It can be seen that the peak area ratio of fragments derived from organic sulfide compounds is small when differential thermal balance-mass spectrometry (TG-DSC-MS) is performed, and it is difficult to generate odor-causing substances even when heated.
On the other hand, the varnish composition of Comparative Example 1 containing dimethyl sulfoxide, which does not correspond to the compound represented by formula (S2), showed that the organic sulfide compound was It can be seen that the peak area ratio of the derived fragments is large, indicating that odor-causing substances are easily generated by heating.

Claims (8)

A varnish composition for forming a polyimide resin, comprising a polyamic acid (A) and a solvent (S),
The solvent (S) includes a nitrogen-containing organic solvent (S-I) and a sulfur-containing organic solvent (S-II),
The nitrogen-containing organic solvent (SI) has the following formula (S1):

(In formula (S1), R ^S1 and R ^S2 are each independently an alkyl group having 1 to 3 carbon atoms, and R ^S3 is a hydrogen atom, or the following formula (S1-1) or the following formula (S1 -2):

R ^S4 is a hydrogen atom or a hydroxyl group, R ^S5 and R ^S6 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ^S7 and R ^S8 is each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when R ^S3 is a group represented by formula (S1-1), R ^S2 and R ^S3 are bonded to each other. may be used to form a ring. )
It is a nitrogen-containing compound represented by
The sulfur-containing organic solvent (S-II) has the following formula (S2):
R ^S9 -S(=O) ₂ -R ^S10 ...(S2)
(In formula (S2), R ^S9 and R ^S10 are each independently an organic group that may contain one or more hetero atoms selected from the group consisting of an oxygen atom, a nitrogen atom, and a halogen atom. , R ^S9 and R ^S10 may be combined with each other to form a ring.)
A varnish composition that is a sulfur-containing compound represented by: The varnish composition according to claim 1, wherein the ratio of the mass of the sulfur-containing organic solvent (S-II) to the mass of the solvent (S) is 1% by mass or more and 30% by mass or less. The varnish composition according to claim 1 or 2, comprising a thermal base generator (B) that generates a basic nitrogen-containing heterocyclic compound by heating. The basic nitrogen-containing heterocyclic compound has the following formula (B1):

(In formula (B1), R ¹ , R ² , and R ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, (phosphino group, phosphinyl group, phosphonato group, or organic group)
The varnish composition according to claim 3, which is a compound represented by: The thermal base generator (B) has the following formula (B2):

(In formula (B2), R ¹ , R ² , and R ³ are the same as those in formula (B1) above, and R ^b1 and R ^b2 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, and a mercapto group. , a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, or an organic group, R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, and a phosphino group. , a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, or an organic group, and R ^b3 , R ^b4 , R ^b5 , R ^b6 , and R ^b7 are two or more of them bonded together to form a cyclic structure. or may contain a heteroatom bond.)
A compound represented by and the following formula (B4):

(In formula (B4), R ¹ , R ² , and R ³ are the same as those in formula (B1) above, R ^b9 represents a hydrogen atom or a monovalent organic group, and R ^b10 represents a substituent represents an aromatic group which may have the following, and the R ^b9 may be bonded to the other R ^b9 or R ^b10 to form a cyclic structure.)
The varnish composition according to claim 4, wherein the varnish composition is one or more selected from the compounds represented by the following. The varnish composition according to any one of claims 1 to 5, wherein the sulfur-containing organic solvent (S-II) is at least one selected from sulfolane and 3-methylsulfolane. When mass spectrometry was performed at a holding temperature of 300°C on the gas generated when the sample of the varnish composition was heated from 30°C to 550°C at a heating rate of 10°C/min in a helium atmosphere, The ratio of the peak area of the fragment derived from the organic sulfide compound to TICC, which is the sum of all intensities from the start m/z to the end m/z of the obtained spectrum, is less than 0.45 area %. The varnish composition according to any one of claims 1 to 6. A molding step of molding the varnish composition according to any one of claims 1 to 7,
A method for producing a polyimide resin, including an imidization step of heating and imidizing the molded varnish composition.