Varnish composition, and method for producing polyimide film

Abstract

To provide a polyimide resin capable of yielding a cured product that is soluble in an organic solvent, has photosensitivity such that it can be cured by action of a photosensitive curing agent, and is excellent in dielectric characteristics in a high-frequency band, a varnish composition containing the polyimide resin, and a method for producing a polyimide film using the varnish composition.SOLUTION: A polyimide resin has a radical-polymerizable group or a cation-polymerizable group coupled to its main chain, and has a skeleton derived from bisphenols having specific structures contained in a structural unit constituting the main chain of the polyimide resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyimide resin, a varnish composition containing the polyimide resin, and a method for producing a polyimide resin film using the varnish composition. [Background technology]

[0002] Polyimide resins have excellent properties such as excellent heat resistance, mechanical strength, insulating properties, and low dielectric constant, and are therefore widely used as insulating and protective materials in electrical and electronic components such as various elements and electronic substrates such as multilayer wiring boards. Generally, polyimide resins are formed by heat-treating at high temperatures a solution of polyamic acid obtained by polymerizing a tetracarboxylic dianhydride component and a diamine component.

[0003] Furthermore, in recent years, communication devices such as mobile phones have become increasingly higher in frequency, which has led to a demand for insulating parts that insulate metal wiring in communication devices to be able to handle higher frequencies. Here, the higher the frequency, the greater the transmission loss, which in turn attenuates the electrical signal. Therefore, in order to accommodate higher frequencies, it is necessary to reduce transmission loss. In this regard, polyimide resins have excellent high-frequency characteristics, exhibiting low dielectric loss tangents and low dielectric constants in the high-frequency band, and are therefore attracting attention as materials that can reduce transmission loss in various substrates and elements used in the high-frequency band.

[0004] As a polyimide resin having such excellent high-frequency characteristics, a polyimide resin has been proposed which is obtained by imidizing at high temperature a polyamic acid obtained by reacting an aromatic tetracarboxylic dianhydride having a specific structure with diaminoquatphenyl (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-080315 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polyimide resin described in Patent Document 1 is formed by applying a varnish containing a polyamic acid precursor and then heating the applied film at a high temperature, as described above. Therefore, when manufacturing a substrate or element containing a polyimide resin, there are significant limitations on the selection of materials to be used together with the polyimide resin from the viewpoint of heat resistance. Furthermore, depending on the design of the substrate or element, it may be required to form the polyimide resin only in a minute area.

[0007] In view of the above circumstances, there is a demand for a photosensitive polyimide resin that is soluble in an organic solvent and can be cured by the action of a photosensitive curing agent. Using such a polyimide resin, a photosensitive varnish can be obtained in which the photosensitive polyimide resin is dissolved in an organic solvent. By using such a photosensitive varnish, the varnish can be applied to a substrate or the like, and then, after removing the organic solvent from the coating, a polyimide resin having a fine and precise shape can be formed by a photolithography method. This method allows the polyimide resin to be formed without heating at a high temperature.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a polyimide resin that is soluble in an organic solvent, has photosensitivity that allows it to be cured by the action of a photosensitive curing agent, and gives a cured product that has excellent dielectric properties in the high frequency band, a varnish composition containing the polyimide resin, and a method for producing a polyimide film using the varnish composition. [Means for solving the problem]

[0009] The present inventors have found that the above-mentioned problems can be solved by bonding a radically polymerizable group or a cationically polymerizable group to the main chain of a polyimide resin and by incorporating a skeleton derived from a bisphenol having a specific structure into the structural units constituting the main chain of the polyimide resin, and have thus completed the present invention. More specifically, the present invention provides the following.

[0010] A first aspect of the present invention is Formula (A1a): [ka] (In formula (A1a), X 1 is a divalent organic residue derived from a diamine, and Y 2 is a tetravalent organic residue derived from a tetracarboxylic dianhydride. and a molecular chain containing a structural unit represented by X 1 as organic residues, and Y 1 At least one of the organic residues as the group represented by the formula (a1): [ka] (In formula (a1), R a1 and R a2 are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; n1 and n2 are each independently an integer of 0 to 4; R a3 and R a4 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a phenyl group; R a3 and R a4 may be bonded to each other to form a ring. It has a partial structure represented by The polyimide resin has a molecular chain containing a radically polymerizable group or a cationically polymerizable group.

[0011] A second aspect of the present invention is a varnish composition comprising the polyimide resin (A) according to the first aspect and an organic solvent (S).

[0012] A third aspect of the present invention is a coating step of applying the varnish composition according to the second aspect onto a substrate to form a coating film; an organic solvent removal step of removing at least a portion of the organic solvent (S) from the coating film; The method for producing a polyimide film includes the steps of: [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a polyimide resin that is soluble in an organic solvent, has photosensitivity that allows it to be cured by the action of a photosensitive curing agent, and gives a cured product that has excellent dielectric properties in the high frequency band, a varnish composition containing the polyimide resin, and a method for producing a polyimide film using the varnish composition. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Polyimide resin> The polyimide resin has the following formula (A1a): [ka] (In formula (A1a), X 1 is a divalent organic group, and Y 1 is a tetravalent organic group. The molecular chain contains a structural unit represented by the formula:

[0015] In the above formula (A1a), X 1 a divalent organic group as 1 At least one of the tetravalent organic groups as the tetravalent organic group is represented by the following formula (a1): [ka] (In formula (a1), R a1 and R a2are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; n1 and n2 are each independently an integer of 0 to 4; R a3 and R a4 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a phenyl group; R a3 and R a4 may be bonded to each other to form a ring. It has a partial structure represented by the following formula:

[0016] Since the polyimide resin has the structural unit represented by the above formula (A1a), the polyimide resin is soluble in various organic solvents. The content of the structural unit represented by the formula (A1a) in the polyimide resin is not particularly limited as long as it does not impair the object of the present invention. The content of the structural unit represented by the formula (A1a) in the polyimide resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the mass of the polyimide resin.

[0017] The molecular chains of the polyimide resin contain radically polymerizable groups or cationically polymerizable groups, and therefore the polyimide resin can be cured by the action of an initiator such as a radical polymerization initiator or a cation polymerization initiator, and can be made insoluble in organic solvents.

[0018] The bonding position of the radical polymerizable group or cationically polymerizable group in the molecular chain of the polyimide resin is not particularly limited. The radical polymerizable group typically includes a group containing an ethylenically unsaturated double bond. As the ethylenically unsaturated double bond-containing group, a vinyl group or an alkenyl group-containing group such as an allyl group is preferred, and a (meth)acryloyl group-containing group is more preferred. Typical examples of the cationically polymerizable group include an epoxy group-containing group, an oxetanyl group-containing group, and a vinyloxy group-containing group. Among these, an epoxy group-containing group and a vinyloxy group-containing group are preferred. As the epoxy group-containing group, an alicyclic epoxy group-containing group or a glycidyl group is preferred. Note that an alicyclic epoxy group is an aliphatic cyclic group in which two adjacent carbon atoms as ring constituent atoms in the aliphatic cyclic group are bonded via an oxygen atom. In other words, an alicyclic epoxy group has an epoxy group containing a three-membered ring consisting of two carbon atoms and one oxygen atom on an aliphatic ring.

[0019] The amount of radically polymerizable groups or cationically polymerizable groups in the polyimide resin is not particularly limited as long as it does not impair the object of the present invention. The amount of radically polymerizable groups or cationically polymerizable groups in the polyimide resin is, for example, preferably 0.0001 mol / g or more and 0.0500 mol / g or less, more preferably 0.0002 mol / g or more and 0.0100 mol / g or less, and even more preferably 0.0005 mol / g or more and 0.0020 mol / g or less, in terms of the number of moles of functional groups relative to the weight of the polyimide resin. The amount of radically polymerizable groups or cationically polymerizable groups in the polyimide resin can typically be measured by NMR analysis.

[0020] The radical polymerizable group is preferably bonded to an aromatic ring in the molecular chain of the polyimide resin. Suitable examples of the radical polymerizable group bonded to an aromatic ring in the molecular chain of the polyimide resin include groups represented by the following formula (A1) or (A2), which do not fall under the category of vinyloxy group-containing groups. -(A 01 ) na -R 01 ···(A1) -(A 01 ) na -R 02 -A 02 -R 01 (A2)

[0021] In formula (A1) and formula (A2), R 01 is an alkenyl group having 2 to 10 carbon atoms. 02is an alkylene group having from 1 to 10 carbon atoms. A 01 is —O—, —CO—, —CO—O—, —O—CO—, —CO—NH—, —NH—CO—, or —NH—. A 02 is —O—, —CO—, —CO—O—, —O—CO—, —CO—NH—, —NH—CO—, or —NH—. na is 0 or 1.

[0022] Specific preferred examples of the radical polymerizable group bonded to the aromatic ring in the main chain include: -OR 03 , -O-CH2CH2-OR 03 , -O-CH2CH2CH2-OR 03 , -O-CH2CH2CH2CH2-OR 03 , -CO-O-CH2CH2-OR 03 , -CO-O-CH2CH2CH2-OR 03 , -CO-O-CH2CH2CH2CH2-OR 03 , -O-CH2CH2-NH-R 03 , -O-CH2CH2CH2-NH-R 03 , -O-CH2CH2CH2CH2-NH-R 03 , -CO-O-CH2CH2-NH-R 03 , -CO-O-CH2CH2CH2-NH-R 03 , -CO-O-CH2CH2CH2CH2-R 03 , -NH-R 03 , -NH-CH2CH2-OR 03 , -NH-CH2CH2CH2-OR 03 , -NH-CH2CH2CH2CH2-OR03 , -CO-NH-CH2CH2-OR 03 , -CO-NH-CH2CH2CH2-OR 03 , -CO-NH-CH2CH2CH2CH2-OR 03 , -NH-CH2CH2-NH-R 03 , -NH-CH2CH2CH2-NH-R 03 , -NH-CH2CH2CH2CH2-NH-R 03 , -CO-NH-CH2CH2-NH-R 03 , -CO-NH-CH2CH2CH2-NH-R 03 , and -CO-NH-CH2CH2CH2CH2-NH-R 03 In these groups, R 03 is an allyl group or a (meth)acryloyl group.

[0023] The cationically polymerizable group is preferably bonded to an aromatic ring in the molecular chain of the polyimide resin. Suitable examples of the cationically polymerizable group bonded to an aromatic ring in the molecular chain of the polyimide resin include a vinyloxy group and groups represented by the following formulae (A3) to (A8). -(A 01 ) na -R 04 ···(A3) -(A 01 ) na -R 02 -R 05 ···(A4) -(A 01 ) na -R 02 -(CO) nb -A 03 -R 04 ···(A5) -(A 01 ) na -R 02 -(CO) nb -A 03 -R07 -R 05 ···(A6) -(A 01 ) na -R 02 -OR 06 (A7) -(A 01 ) na -R 02 -(CO) nb -A 03 -R 07 -OR 06 ···(A8)

[0024] In formulas (A3) to (A8), R 02 is an alkylene group having 1 to 10 carbon atoms. 04 R is an epoxyalkyl group having 2 to 20 carbon atoms, or an alicyclic epoxy group having 3 to 20 carbon atoms. 05 R is an alicyclic epoxy group having 3 to 20 carbon atoms. 06 is a vinyl group. 07 is an alkylene group having from 1 to 10 carbon atoms. A 01 is —O—, —CO—, —CO—O—, —O—CO—, —CO—NH—, —NH—CO—, or —NH—. A 03 is —O— or —NH—. nb is 0 or 1.

[0025] Specific preferred examples of the cationically polymerizable group bonded to the aromatic ring in the main chain include: -R 07 , -O-CH2CH2-R 07 , -O-CH2CH2CH2-R 07 , -O-CH2CH2CH2CH2-R 07 , -CO-O-CH2CH2-R 07 , -CO-O-CH2CH2CH2-R 07 , -CO-O-CH2CH2CH2CH2-R07 , -NH-CH2CH2-R 07 , -NH-CH2CH2CH2-R 07 , -NH-CH2CH2CH2CH2-R 07 , -CO-NH-CH2CH2-R 07 , -CO-NH-CH2CH2CH2-R 07 , and -CO-NH-CH2CH2CH2CH2-R 07 In these groups, R 07 is a vinyloxy group, a glycidyloxy group, an epoxycyclopentyl group, an epoxycyclohexyl group, or an epoxycycloheptyl group.

[0026] In the above formula (A1a), X 1 is a divalent organic group. The divalent organic group is not particularly limited as long as it does not impair the object of the present invention. The divalent organic group is typically a divalent organic residue derived from a diamine used as a raw material for polyamic acid, which is a precursor of a polyimide resin. In the above formula (A1a), Y 1 is a tetravalent organic group. The tetravalent organic group is not particularly limited as long as it does not impair the object of the present invention. The tetravalent organic group is typically an organic residue of 4 derived from a tetracarboxylic dianhydride used as a raw material for polyamic acid, which is a precursor of a polyimide resin. As mentioned above, X 1 and Y 1 At least one of the organic groups has a partial structure represented by the above formula (a1).

[0027] In formula (a1), R a1 and R a2Examples of the alkyl group having 1 to 4 carbon atoms as the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Among these alkyl groups, a methyl group and an ethyl group are preferred, and a methyl group is more preferred. In formula (a1), R a1 and R a2 Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, and a tert-butyloxy group. Among these alkoxy groups, a methoxy group and an ethoxy group are preferred, and a methoxy group is more preferred. In formula (a1), R a1 and R a2 Examples of the halogen atom as the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these halogen atoms, a chlorine atom and a bromine atom are preferred.

[0028] In formula (a1), n1 and n2 each independently represent an integer of 0 or more and 4 or less. Because of the ease of availability of a monomer compound for producing polyamic acid, which is a precursor of a polyimide resin, n1 and n2 each preferably represent an integer of 0 or more and 2 or less, and more preferably 0.

[0029] In formula (a1), R a3 and R a4 Examples of the alkyl group having 1 to 4 carbon atoms as the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. In formula (a1), R a3 and R a4Examples of the alkyl group having 1 to 4 carbon atoms as the alkyl group include a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, and a 1,1,2,2,2-pentafluoroethyl group. R in formula (a1) a3 and R a4 As the alkyl group, a hydrogen atom, a methyl group, an ethyl group, a trifluoromethyl group, and a phenyl group are preferred because the polyimide resin has good solubility in organic solvents and the monomer compounds for producing polyamic acid, which is a precursor of the polyimide resin, are easily available. Also, R a3 and R a4 and preferably combine with each other to form a cycloalkylidene group having 5 to 8 carbon atoms, such as a cyclopentylidene group, a cyclohexylidene group, a cycloheptylidene group, or a cyclooctylidene group.

[0030] Specific preferred examples of the partial structure represented by formula (a1) include the following structures: [ka]

[0031] The molecular chain of the polyimide resin contains the structural unit represented by formula (A1a) and the structural unit represented by formula (A1b): [ka] (In formula (A1b), X 2 and X 3 each independently represents a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; Y 2 is a tetravalent organic group that does not have a partial structure represented by formula (a1), and R a1 , R a2 , R a3 , R a4, n1, and n2 are the same as those in formula (a1). A structural unit represented by the following formula (A1c): [ka] (In formula (A1c), X 4 is a divalent organic group that does not have a partial structure represented by formula (a1), and Y 3 and Y 4 are each independently a trivalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; R a1 , R a2 , R a3 , R a4 , n1, and n2 are the same as those in formula (a1). and structural units represented by the following formula (A1d): [ka] (In formula (A1d), X 5 and X 6 each independently represents a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; Y 5 and Y 6 are each independently a trivalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; R a1 , R a2 , R a3 , R a4 , n1, and n2 are the same as those in formula (a1). It is preferable that the polymer contains one or more structural units selected from the group consisting of structural units represented by the following formula:

[0032] X in formula (A1b) 2 and X 3are each independently a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom. Examples of the alkyl group having 1 to 4 carbon atoms as a substituent include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Among these alkyl groups, a methyl group and an ethyl group are preferred, and a methyl group is more preferred. Examples of the alkoxy group having 1 to 4 carbon atoms as a substituent include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, and a tert-butyloxy group. Among these alkoxy groups, a methoxy group and an ethoxy group are preferred, and a methoxy group is more preferred. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these halogen atoms, a chlorine atom and a bromine atom are preferred.

[0033] X 2 and X 3 The number of carbon atoms in the aromatic hydrocarbon group as the aryl group is not particularly limited, and is, for example, preferably from 6 to 50, and more preferably from 6 to 20. The number of carbon atoms in the aromatic hydrocarbon group does not include the number of carbon atoms in the substituent. X 2 and X 3 Preferred aromatic hydrocarbon groups as the aromatic hydrocarbon group include phenylene groups such as o-phenylene, m-phenylene, and p-phenylene; naphthalenediyl groups such as naphthalene-1,4-diyl, naphthalene-1,3-diyl, naphthalene-2,6-diyl, and naphthalene-2,7-diyl; and biphenyldiyl groups such as biphenyl-4,4'-diyl, biphenyl-3,4'-diyl, and biphenyl-3,3'-diyl.

[0034] X 2 and X 3As the alkyl group, a p-phenylene group, an m-phenylene group, a naphthalene-1,4-diyl group, and a biphenyl-4,4'-diyl group are preferred, a p-phenylene group and a biphenyl-4,4'-diyl group are more preferred, and a p-phenylene group is even more preferred.

[0035] Y in formula (A1b) 2 Y is a tetravalent organic group that does not have the partial structure represented by formula (a1). 2 The tetravalent organic group as is typically a tetravalent organic residue derived from a tetracarboxylic dianhydride used as a raw material for polyamic acid, which is a precursor of a polyimide resin. Examples of tetracarboxylic dianhydrides that provide the tetravalent organic residue include compounds represented by the following formula (a1-1). One type of tetracarboxylic dianhydride may be used alone, or two or more types may be used in combination. [ka] (In formula (a1-1), A 1 is a tetravalent organic group having 6 to 50 carbon atoms. 1 The tetravalent organic group as the formula (a1) does not include a partial structure represented by the formula (a1).

[0036] In formula (a1-1), A 1 is a tetravalent organic group having 6 to 50 carbon atoms, which may have one or more substituents in addition to the two acid anhydride groups represented by —CO—O—CO— in formula (a1-1). Preferred examples of the substituent include a fluorine atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a fluorinated alkyl group having from 1 to 6 carbon atoms, and a fluorinated alkoxy group having from 1 to 6 carbon atoms. 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. The same applies to the above-mentioned substituents and to one or more substituents that the aromatic group described below may have on the aromatic ring.

[0037] A 1 The number of carbon atoms constituting A is more preferably 8 or more, and even more preferably 12 or more. 1 The number of carbon atoms constituting A is more preferably 40 or less, and even more preferably 30 or less. 1 A may be an aliphatic group, an aromatic group, or a group that combines these structures. 1 A may contain, in addition to carbon and hydrogen atoms, halogen atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. 1 When A contains an oxygen atom, a nitrogen atom, or a sulfur atom, the oxygen atom, the nitrogen atom, or the sulfur atom is preferably a group selected from a nitrogen-containing heterocyclic group, -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO2-, -S-, and -SS-, 1 A may be included as a group selected from -O-, -CO-, -SO-, -SO2-, -S-, and -SS-. 1 It is more preferred that the .alpha.-.beta.

[0038] The tetracarboxylic dianhydride represented by formula (a1-1) can be appropriately selected from tetracarboxylic dianhydrides that have conventionally been used as raw materials for synthesizing polyamic acids, as long as it satisfies the above-mentioned predetermined conditions. The tetracarboxylic dianhydride may be an aliphatic tetracarboxylic dianhydride or an aromatic tetracarboxylic dianhydride.

[0039] Examples of aliphatic tetracarboxylic dianhydrides include 2,2-bis(3,4-dicarboxy)propane dianhydride and bis(3,4-dicarboxy)methane dianhydride. The aliphatic tetracarboxylic dianhydride may also contain an alicyclic structure. The alicyclic structure may be polycyclic. Examples of polycyclic alicyclic structures include bridged alicyclic structures such as bicyclo[2.2.1]heptane. For example, a bridged alicyclic structure may be condensed with another bridged alicyclic structure and / or a non-bridged alicyclic structure, or a bridged alicyclic structure may be connected to another bridged alicyclic structure and / or a non-bridged alicyclic structure via a spiro bond. When an aliphatic tetracarboxylic dianhydride is used, a cured product having excellent transparency tends to be obtained using the composition.

[0040] In addition, A in formula (a1-1) 1 As the aliphatic group constituting the formula (a1), for example, a tetravalent group represented by the following formula (a2) can be used: When such a group is used, a polyimide resin with excellent transparency tends to be obtained. In order to facilitate purification of the raw material compound, a in formula (a2) is preferably 5 or less, and more preferably 3 or less. In order to provide excellent chemical stability to the raw material compound that provides the structural unit represented by formula (a1), a is preferably 1 or more, and more preferably 2 or more. In formula (a2), a is particularly preferably 2 or 3. [ka] (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, and a is an integer of 0 to 12.

[0041] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 3,3',4,4'-oxybisphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride.

[0042] The aromatic tetracarboxylic dianhydride may also be, for example, a compound represented by the following general formulas (a1-2) to (a1-4). [ka]

[0043] In the above formula (a1-2) and formula (a1-3), R a01 , R a02 and R a03 R represents a divalent group that is an aliphatic group optionally substituted with halogen, an oxygen atom, a sulfur atom, an aromatic group connected via one or more divalent elements, or a combination thereof. a02 and R a03 may be the same or different. That is, R a01 , R a02 and R a03 may contain a carbon-carbon single bond, a carbon-oxygen-carbon ether bond, or a halogen atom (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.

[0044] In addition, in the above formula (a1-4), R a04 , R a05R represents a monovalent substituent that is an aliphatic group optionally substituted with halogen, an aromatic group substituted with one or more divalent elements, or a halogen, or a combination thereof. a04 , and R a05 may be the same or different. As the compound represented by formula (a1-4), difluoropyromellitic dianhydride, dichloropyromellitic dianhydride, and the like can also be used.

[0045] Furthermore, the polyimide resin has radically polymerizable groups or cationically polymerizable groups on its molecular chain. Therefore, the tetravalent organic group Y in formula (A1b) 2 may be a group represented by the following formulae (A1-1) to (A1-3). [ka] R in formulas (A1-1) to (A1-3) a01 , Ra 02 , and R a03 represents R in the above formulas (a1-1), (a1-2), and (a1-3). a01 , Ra 02 , and R a03 is the same as: In formula (A1-1), formula (A1-2), and formula (A1-3), Ra 06 is a radical polymerizable group or a cationically polymerizable group. Examples of the radical polymerizable group or the cationically polymerizable group include the groups described above. Tetracarboxylic dianhydrides themselves are highly reactive. For example, epoxy groups react easily with carboxylic anhydride groups. 2 is a group represented by formula (A1-1), formula (A1-2), or formula (A1-3), it is preferable to introduce a radically polymerizable group or a cationically polymerizable group into the molecular chain of the polyamic acid or polyimide resin after synthesizing the polyamic acid or polyimide resin.

[0046] Examples of reactions for introducing a radical polymerizable group or a cation polymerizable group include: 1) an etherification reaction between a halogen atom bonded to an aromatic ring in the molecular chain of a polyamic acid or polyimide resin and an alcohol compound having a radical polymerizable group or a cation polymerizable group; 2) an esterification reaction between a hydroxyl group bonded to an aromatic ring in the molecular chain of a polyamic acid or polyimide resin and a carboxylic acid halide having a radical polymerizable group or a cation polymerizable group; 3) an esterification reaction between a carboxyl group bonded to an aromatic ring in the molecular chain of a polyimide resin and an organic halide having a radical polymerizable group or a cationically polymerizable group; and 4) N-substitution reaction between an amino group bonded to an aromatic ring in the molecular chain of a polyamic acid or polyimide resin and an organic halide having a radical polymerizable group or a cationically polymerizable group. The reaction for introducing a radical polymerizable group or a cationically polymerizable group is not limited to these reactions.

[0047] For example, a polyamic acid or polyimide resin having a hydroxyl group protected by a protecting group such as an acetyl group, a carboxylic acid ester group such as a methoxycarbonyl group, or an amino group protected by a protecting group such as a tert-butoxycarbonyl group on an aromatic ring can be synthesized, and then deprotected by a well-known method to obtain a polyamic acid or polyimide resin having a hydroxyl group, carboxyl group, amino group, or the like on an aromatic ring.

[0048] Y in formula (A1c) 3 and Y 4 are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom. Suitable examples of the alkyl group having 1 to 4 carbon atoms, the alkoxy group having 1 to 4 carbon atoms, and the halogen atom as the substituent include X 2 and X 3 These are the same as the preferred examples of the substituent that the aromatic hydrocarbon group may have.

[0049] Y3 and Y 4 The number of carbon atoms in the aromatic hydrocarbon group as the aryl group is not particularly limited, and is, for example, preferably from 6 to 50, and more preferably from 6 to 20. The number of carbon atoms in the aromatic hydrocarbon group does not include the number of carbon atoms in the substituent. Y 3 and Y 4 Examples of the aromatic hydrocarbon group as the aromatic hydrocarbon group include benzenetriyl groups such as a benzene-1,2,3-triyl group and a benzene-1,2,4-triyl group, naphthalenetriyl groups such as a naphthalene-1,2,4-triyl group, a naphthalene-2,3,6-triyl group and a naphthalene-1,3,8-triyl group, and biphenyltriyl groups such as a biphenyl-3,4,4'-triyl group and a biphenyl-3,4,3'-triyl group.

[0050] Y 3 and Y 4 As the alkyl group, a benzene-1,2,3-triyl group, a benzene-1,2,4-triyl group, a biphenyl-3,4,4'-triyl group, and a biphenyl-3,4,3'-triyl group are preferred, a benzene-1,2,4-triyl group and a biphenyl-3,4,4'-triyl group are more preferred, and a benzene-1,2,4-triyl group is even more preferred.

[0051] X in formula (A1c) 4 is a divalent organic group that does not have the partial structure represented by formula (a1). 4 The divalent organic group as is typically a divalent organic residue derived from a diamine used as a raw material for polyamic acid, which is a precursor of a polyimide resin. Examples of diamines that provide the divalent organic residue include compounds represented by the following formula (a3-1): A compound represented by the following formula (a3-1) can be typically used: The diamine compounds may be used singly or in combination of two or more. H2N-A 2 -NH2···(a3-1) (In formula (a3-1), A 2 represents a divalent organic group. 2The divalent organic group as the formula (a1) does not include a partial structure represented by the formula (a1).

[0052] In formula (a3-1), A 2 is a divalent organic group, which may have one or more substituents in addition to the two amino groups in formula (a3-1). Preferred examples of the substituent are a fluorine atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a fluorinated alkyl group having from 1 to 6 carbon atoms, a fluorinated alkoxy group having from 1 to 6 carbon atoms, or a hydroxyl group. When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferably a perfluoroalkyl group or a perfluoroalkoxy group.

[0053] In formula (a3-1), A 2 The lower limit of the number of carbon atoms in the organic group is preferably 2, more preferably 6, and the upper limit is preferably 50, more preferably 30. A 2 Although may be an aliphatic group, it is preferably an organic group containing one or more aromatic rings.

[0054] A 2 When A is an organic group containing one or more aromatic rings, the organic group may be one aromatic group itself, or may be a group in which two or more aromatic groups are bonded via a bond containing an aliphatic hydrocarbon group, a halogenated aliphatic hydrocarbon group, or a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. 2 Examples of bonds containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom included in the formula (I) include -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO2-, -S-, and -SS-, and -O-, -CO-, -SO-, -SO2-, -S-, and -SS- are preferred.

[0055] A 2 The aromatic ring bonded to the amino group in A is preferably a benzene ring. 2When the ring bonded to the amino group in the fused ring is a fused ring containing two or more rings, the ring bonded to the amino group in the fused ring is preferably a benzene ring. Also, A 2 The aromatic ring contained in may be an aromatic heterocycle.

[0056] A 2 When is an organic group containing an aromatic ring, from the viewpoint of the heat resistance of a cured product formed using the resin composition, the organic group is preferably at least one of groups represented by the following formulas (21) to (24). [ka] (In formulas (21) to (24), R 111 represents one selected from the group consisting of a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group having from 1 to 4 carbon atoms, and a halogenated alkyl group having from 1 to 4 carbon atoms. In formula (24), Q represents a 9,9'-fluorenylidene group, or a group represented by the formula: -C6H4-, -CONH-C6H4-NHCO-, -NHCO-C6H4-CONH-, -O-C6H4-CO-C6H4-O-, -OCO-C6H4-COO-, -OCO-, -O-, -S-, -CO-, -CONH-, -SO2-, -C(CF3)2-, -C(CH3)2-, -CH2-, -O-C6H4-SO2-C6H4-O-, -C(CH3)2-C6H4-C(CH3)2-, -OC 10 It represents one kind selected from the group consisting of groups represented by -H6-O-, -O-C6H4-C6H4-O-, and -O-C6H4-O-. In the examples of Q, -C6H4- is a phenylene group, preferably an m-phenylene group or a p-phenylene group, more preferably a p-phenylene group. 10 H6- is a naphthalenediyl group, preferably a naphthalene-1,2-diyl group, a naphthalene-1,4-diyl group, a naphthalene-2,3-diyl group, a naphthalene-2,6-diyl group, or a naphthalene-2,7-diyl group, more preferably a naphthalene-1,4-diyl group or a naphthalene-2,6-diyl group.

[0057] R in equations (21) to (24) 111 From the viewpoint of the heat resistance of the polyimide resin to be formed, a hydrogen atom, a hydroxyl group, a fluorine atom, a methyl group, an ethyl group, or a trifluoromethyl group is more preferred, and a hydrogen atom, a hydroxyl group, or a trifluoromethyl group is particularly preferred.

[0058] In terms of the heat resistance of the polyimide resin to be formed, Q in formula (24) is preferably a 9,9'-fluorenylidene group, -O-C6H4-O-, -C(CF3)2-, -O-, -C(CH3)2-, -CH2-, or -CONH-.

[0059] When an aromatic diamine is used as the diamine compound represented by formula (a3-1), for example, the aromatic diamines shown below can be suitably used. That is, examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzanilide ... Examples of suitable diaminobenzanilide include 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, 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. 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.

[0060] Also, A 2 As the silicon atom-containing group, a silicon atom-containing group which may have a chain aliphatic group and / or an aromatic ring can be used. As such a silicon atom-containing group, the following groups can typically be used: [ka]

[0061] In addition, from the viewpoint of further improving the mechanical properties of the resulting polyimide resin, A 2 As the alkyl group, a group represented by the following formula (Si-1) can also be preferably used. [ka] (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, an arylene group having 6 to 20 carbon atoms, or the like; R 114 , R 115 , R 116 , and R 117 each independently represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a group containing an amino group having 20 or less carbon atoms, -OR 118 A group represented by (R 118 is a hydrocarbon group having 1 to 20 carbon atoms, an organic group having 2 to 20 carbon atoms and containing one or more epoxy groups, and l is an integer of 3 to 50.

[0062] R in formula (Si-1) 112 and R 113 In the above, the alkylene group having 2 to 20 carbon atoms is preferably an alkylene group having 2 to 10 carbon atoms from the viewpoint of heat resistance and residual stress, and examples thereof include a dimethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.

[0063] R in formula (Si-1) 112 and R 113 In the above, the cycloalkylene group having 3 to 20 carbon atoms is preferably a cycloalkylene group having 3 to 10 carbon atoms from the viewpoint of heat resistance and residual stress, and examples thereof include a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, and a cycloheptylene group. R in formula (Si-1) 112 and R 113 In the above, the arylene group having 6 to 20 carbon atoms is preferably an aromatic group having 6 to 20 carbon atoms from the viewpoint of heat resistance and residual stress, and examples thereof include a phenylene group and a naphthylene group.

[0064] R in formula (Si-1)114 , R 115 , R 116 , and R 117 In terms of heat resistance and residual stress, the alkyl group having 1 to 20 carbon atoms in the formula (I) is preferably an alkyl group having 1 to 10 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 In terms of heat resistance and residual stress, the cycloalkyl group having 3 to 20 carbon atoms is preferably a cycloalkyl group having 3 to 10 carbon atoms, and specific examples include a cyclopentyl group and a cyclohexyl group. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 In terms of heat resistance and residual stress, the aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 12 carbon atoms, and specific examples thereof include a phenyl group, a tolyl group, and a naphthyl group. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 Examples of the amino group-containing group having 20 or less carbon atoms in the formula include an amino group and a substituted amino group (for example, a bis(trialkylsilyl)amino group). R in formula (Si-1) 114 , R 115 , R 116 , and R 117 -OR in 118 Examples of the group represented by the formula (I) include a methoxy group, an ethoxy group, a propoxy group, an isopropyloxy group, a butoxy group, a phenoxy group, a tolyloxy group, a naphthyloxy group, a propenyloxy group (for example, an allyloxy group), and a cyclohexyloxy group. Among them, R 114 , R 115 , R 116 , and R117 is preferably a methyl group, an ethyl group, a propyl group, or a phenyl group.

[0065] The group represented by formula (Si-1) can be derived by reacting a silicon-containing compound having amino groups at both ends with an acid anhydride. Specific examples of such silicon-containing compounds include methylphenyl silicones modified with amino groups at both ends (for example, X-22-1660B-3 (number average molecular weight about 4,400) and X-22-9409 (number average molecular weight about 1,300) manufactured by Shin-Etsu Chemical Co., Ltd.), dimethyl silicones modified with amino groups at both ends (for example, X-22-161A (number average molecular weight about 1,600), X-22-161B (number average molecular weight about 3,000) and KF8012 (number average molecular weight about 4,400) manufactured by Shin-Etsu Chemical Co., Ltd.; BY16-835U (number average molecular weight about 900) manufactured by Toray Dow Corning; and Silaplane FM3311 (number average molecular weight about 1000) manufactured by JNC Corporation).

[0066] The polyimide resin has radically polymerizable groups or cationically polymerizable groups on its molecular chain. Therefore, the divalent organic group X in formula (A1c) 4 may be, for example, an aromatic group represented by any one of the above formulas (21) to (24) to which a radical polymerizable group or a cation polymerizable group is further bonded on the aromatic ring.

[0067] Organic group X having a radical polymerizable group or a cationic polymerizable group 4 Specific preferred examples of the group include the following groups: [ka]

[0068] [ka]

[0069] [ka]

[0070] In formula (A1d), X 5 and X 6 are each independently a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom. X 5 and X 6 The divalent aromatic hydrocarbon group as X in formula (A1b) is 2 and X 3 The same applies to the divalent aromatic hydrocarbon group as

[0071] In formula (A1d), Y 5 and Y 6 are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom. Y 5 and Y 6 The trivalent aromatic hydrocarbon group as Y 3 and Y 4 The same applies to the trivalent aromatic hydrocarbon group as

[0072] In formula (A1d), R a1 , R a2 , R a3 , R a4 , n1, and n2 are the same as those in formula (a1).

[0073] As the structural unit represented by formula (A1a), a structural unit represented by formula (A1c) is preferred, for reasons such as the ease of synthesis and availability of raw materials for synthesizing the polyimide resin, and the ease of introducing a radically polymerizable group or a cationically polymerizable group into the structural unit. The ratio of the mass of the structural unit represented by formula (A1c) to the mass of the structural unit represented by formula (A1a) is preferably 50 mass% or more, more preferably 80 mass% or more, even more preferably 90 mass% or more, and particularly preferably 100 mass%.

[0074] The polyimide resin may contain a structural unit represented by the following formula (A1e) to the extent that the object of the present invention is not impaired. The structural unit represented by the following formula (A1e) does not have the partial structure represented by the above formula (a1). [ka] (In formula (A1e), X 4 is X in formula (A1c) 4 and Y 2 is Y in formula (A1b) 2 is the same as

[0075] The method for producing the polyimide resin described above is not particularly limited. The polyimide resin described above can typically be produced by reacting a polyamic acid having a structure corresponding to the structure of the structural unit described above with a tetracarboxylic dianhydride to obtain a polyamic acid, and then imidizing the polyamic acid. When producing the polyamic acid, one type of tetracarboxylic dianhydride and one type of diamine may be used alone, or two or more types may be used in combination. As described above, the polyimide resin has a radical polymerizable group or a cationically polymerizable group, which may be introduced into the molecular chain after synthesis of the polyamic acid or the polyimide resin. When a radically polymerizable group or a cationically polymerizable group is introduced onto the molecular chain of the polyamic acid or polyimide resin (A) after synthesis of the polyamic acid or polyimide resin (A), the method for the introduction is not particularly limited. Since an undesired side reaction is likely to occur between a carboxyl group or an amide bond and a radically polymerizable group or a cationically polymerizable group, it is preferable to introduce a radically polymerizable group or a cationically polymerizable group into the polyimide resin (A) rather than into the polyamic acid. A typical example of a method for introducing a radically polymerizable group or a cationically polymerizable group onto a molecular chain includes a method of reacting a polyamic acid or polyimide resin (A) having a functional group such as a hydroxyl group, an amino group, or a carboxyl group with a carboxylic acid having a radically polymerizable group, a carboxylic acid halide having a radically polymerizable group, an alcohol having a radically polymerizable group, a phenol having a radically polymerizable group, an amine having a radically polymerizable group, a halogenated compound having a radically polymerizable group, a carboxylic acid having a cationically polymerizable group, a carboxylic acid halide having a cationically polymerizable group, an alcohol having a cationically polymerizable group, a phenol having a cationically polymerizable group, an amine having a cationically polymerizable group, or a halogenated compound having a cationically polymerizable group by a known method such as a condensation reaction using a known condensing agent or Williamson's etherification reaction.

[0076] The amounts of the tetracarboxylic dianhydride and the diamine compound used when synthesizing the polyamic acid are not particularly limited, but the amount of the diamine compound used is preferably 0.50 mol or more and 1.50 mol or less, more preferably 0.60 mol or more and 1.30 mol or less, and particularly preferably 0.70 mol or more and 1.20 mol or less, per 1 mol of the tetracarboxylic dianhydride. The weight-average molecular weight of the resulting polyamic acid may be appropriately set depending on its intended use. The weight-average molecular weight of the polyamic acid 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 resulting polyamic acid is, for example, 100,000 or less, preferably 80,000 or less, and more preferably 75,000 or less. The weight average molecular weight can be adjusted to the above value by adjusting the amounts of the tetracarboxylic dianhydride and the diamine compound blended, and reaction conditions such as the solvent and reaction temperature.

[0077] 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 a tetracarboxylic dianhydride and a diamine compound is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride and the diamine compound and does not react with the tetracarboxylic dianhydride and the diamine compound. The organic solvent can be used alone or in combination of two or more kinds.

[0078] Examples of the organic solvent used in the reaction of the tetracarboxylic dianhydride with the diamine compound include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylcaprolactam, and N,N,N',N'-tetramethylurea; dimethyl sulfoxide; acetonitrile; and ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, and tetrahydrofuran.

[0079] Among these organic solvents, nitrogen-containing polar solvents such as 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 in terms of the solubility of the resulting polyamic acid and polyimide resin.

[0080] The temperature at which the tetracarboxylic dianhydride and the diamine compound are reacted is not particularly limited as long as the reaction proceeds smoothly. 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, and particularly preferably 0° C. or higher and 70° C. or lower. The reaction time between the tetracarboxylic dianhydride and the diamine compound varies depending on the reaction temperature, but is typically preferably 1 hour or higher and 50 hours or lower, more preferably 2 hours or higher and 40 hours or lower, and particularly preferably 5 hours or higher and 30 hours or lower.

[0081] By the method described above, a solution containing polyamic acid is obtained. The resulting polyamic acid is imidized by ring closure to produce polyimide resin (A). The method of imidization is not particularly limited, and the imidization may be carried out by heating or using an imidizing agent.

[0082] When imidization is carried out by heating, the heating may be carried out on a solution or suspension of the polyamic acid, or on a solid polyamic acid. Since the polyimide resin (A) exhibits excellent solubility in organic solvents, the heating for imidization is preferably carried out on a solution of the polyamic acid. When the polyamic acid solution is heated to effect imidization, it is preferable to carry out the heating while removing water produced as a by-product during the imidization. The heating conditions for imidization are not particularly limited as long as the polyamic acid or polyimide resin (A) is not decomposed and the imidization proceeds satisfactorily. When a polyamic acid solution is heated, the heating temperature is typically preferably 150° C. or higher and 280° C. or lower, more preferably 160° C. or higher and 250° C. or lower, and particularly preferably 170° C. or higher and 230° C. When a solid polyamic acid is heated, the heating temperature is typically preferably 180° C. or higher and 400° C. or lower, and more preferably 200° C. or higher and 350° C. or lower. The heating time varies depending on the heating temperature, but is typically preferably from 1 hour to 24 hours, more preferably from 2 hours to 12 hours.

[0083] When imidizing a polyamic acid with an imidizing agent, the imidization is usually carried out by adding the imidizing agent to a solution or suspension of the polyamic acid. Examples of organic solvents that can be used when imidizing with an imidizing agent include the same organic solvents that can be used in preparing polyamic acid. When imidization is performed using an imidizing agent, the concentration of polyamic acid in the polyamic acid solution or suspension is not particularly limited. Typically, the concentration of polyamic acid in the polyamic acid solution or suspension is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 30% by mass or less. The amount of the imidizing agent used is not particularly limited, and is selected depending on the type of the imidizing agent so that the polyamic acid is imidized to a desired degree. The reaction temperature when imidization is carried out using an imidizing agent is not particularly limited, and is, for example, preferably 0°C or higher and 100°C or lower, more preferably 5°C or higher and 50°C or lower. The time for the imidization reaction when an imidizing agent is used is not particularly limited. Depending on the type of imidizing agent, the imidization reaction is preferably carried out for about 30 minutes to 24 hours, more preferably 1 hour to 12 hours, and even more preferably 2 hours to 6 hours.

[0084] Examples of the imidizing agent include dehydrating agents such as acetic anhydride, propionic anhydride, benzoic anhydride, trifluoroacetic anhydride, acetyl chloride, tosyl chloride, mesyl chloride, ethyl chloroformate, triphenylphosphine and dibenzimidazolyl disulfide, dicyclohexylcarbodiimide, carbodiimidazole, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, and oxalic acid N,N'-disuccinimidyl ester; and basic compounds such as pyridine, picoline, 2,6-lutidine, collidine, triethylamine, N-methylmorpholine, 4-N,N'-dimethylaminopyridine, isoquinoline, triethylamine, 1,4-diazabicyclo[2.2.2]octane, and 1,8-diazabicyclo[5.4.0]-7-undecene.

[0085] <Varnish composition> The varnish composition contains the aforementioned polyimide resin as polyimide resin (A) in an organic solvent (S). As described above, the polyimide resin (A) is soluble in the organic solvent (S). Therefore, in the varnish composition, at least a portion of the polyimide resin (A) is dissolved in the organic solvent (S). In the varnish composition, at 20°C, preferably 80 mass % or more of the polyimide resin (A) is dissolved in the organic solvent (S), more preferably 90 mass % or more of the polyimide resin (A) is dissolved in the organic solvent (S), and particularly preferably 100 mass % or more of the polyimide resin (A) is dissolved in the organic solvent (S). That is, the varnish composition is preferably a solution in which the polyimide resin (A) is completely dissolved in the organic solvent (S).

[0086] The mass ratio of the polyimide resin (A) to the mass of the varnish composition is determined appropriately taking into consideration the viscosity of the varnish composition, the coating method, and the thickness of the coating film. The mass ratio of the polyimide resin (A) to the mass of the varnish composition is typically preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0087] When the polyimide resin (A) has a radical polymerizable group, the varnish composition may contain, in addition to the polyimide resin (A), a monomer compound having an ethylenically unsaturated double bond as the monomer compound (B). Such a monomer compound may be a monofunctional monomer compound or a polyfunctional monomer compound, and a polyfunctional monomer compound is preferred.

[0088] Examples of the monofunctional monomer compound include (meth)acrylamide, methylol (meth)acrylamide, methoxymethyl (meth)acrylamide, ethoxymethyl (meth)acrylamide, propoxymethyl (meth)acrylamide, butoxymethoxymethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, crotonic acid, 2-acrylamido-2-methylpropanesulfonic acid, tert-butylacrylamidosulfonic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, Examples of the photopolymerizable monomer include 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-(meth)acryloyloxy-2-hydroxypropyl phthalate, glycerin mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylamino (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, and half (meth)acrylates of phthalic acid derivatives. These monofunctional photopolymerizable monomers can be used alone or in combination of two or more.

[0089] Examples of polyfunctional monomer compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane ... Examples of suitable polyfunctional monomer compounds include (4-(meth)acryloxypolyethoxyphenyl)propane, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid diglycidyl ester di(meth)acrylate, glycerin triacrylate, glycerin polyglycidyl ether poly(meth)acrylate, urethane (meth)acrylate (i.e., tolylene diisocyanate), a reaction product of trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and 2-hydroxyethyl (meth)acrylate, methylene bis(meth)acrylamide, (meth)acrylamido methylene ether, and a condensation product of a polyhydric alcohol and N-methylol (meth)acrylamide, as well as triacryl formal. These polyfunctional monomer compounds can be used alone or in combination of two or more.

[0090] Among these monomer compounds having an ethylenically unsaturated double bond, polyfunctional monomer compounds having three or more functionalities are preferred, polyfunctional monomer compounds having four or more functionalities are more preferred, and polyfunctional monomer compounds having five or more functionalities are even more preferred, as they tend to improve the adhesion of the cured product to the substrate and the strength of the cured product.

[0091] When the polyimide resin (A) has a vinyloxy group-containing group as a cationically polymerizable group, the varnish composition may contain a vinyl ether compound as the monomer compound (B) together with the polyimide resin (A). Such a vinyl ether compound may be a monofunctional compound or a polyfunctional compound.

[0092] Specific preferred examples of the vinyl ether compound include vinyl phenyl ether, 4-vinyloxytoluene, 3-vinyloxytoluene, 2-vinyloxytoluene, 1-vinyloxy-4-chlorobenzene, 1-vinyloxy-3-chlorobenzene, 1-vinyloxy-2-chlorobenzene, 1-vinyloxy-2,3-dimethylbenzene, 1-vinyloxy-2,4-dimethylbenzene, 1-vinyloxy-2,5-dimethylbenzene, and 1-vinyloxy-2,6-dimethylbenzene. Aromatic monovinyl ethers such as methylbenzene, 1-vinyloxy-3,4-dimethylbenzene, 1-vinyloxy-3,5-dimethylbenzene, 1-vinyloxynaphthalene, 2-vinyloxynaphthalene, 2-vinyloxyfluorene, 3-vinyloxyfluorene, 4-vinyloxy-1,1'-biphenyl, 3-vinyloxy-1,1'-biphenyl, 2-vinyloxy-1,1'-biphenyl, 6-vinyloxytetralin, and 5-vinyloxytetralin Compounds: 1,4-divinyloxybenzene, 1,3-divinyloxybenzene, 1,2-divinyloxybenzene, 1,4-divinyloxynaphthalene, 1,3-divinyloxynaphthalene, 1,2-divinyloxynaphthalene, 1,5-divinyloxynaphthalene, 1,6-divinyloxynaphthalene, 1,7-divinyloxynaphthalene, 1,8-divinyloxynaphthalene, 2,3-divinyloxynaphthalene, 2,6-divinyloxynaphthalene, 2,7-divinyloxy and aromatic divinyl ether compounds such as bisphenol A divinyl ether. These vinyl ether compounds may be used in combination of two or more kinds.

[0093] When the polyimide resin (A) has an epoxy group-containing group as the cationically polymerizable group, the varnish composition may contain various epoxy compounds as the monomer compound (B). Examples of epoxy compounds include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, naphthalene type epoxy resin, and biphenyl type epoxy resin; novolac epoxy resins such as phenol novolac type epoxy resin, brominated phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, and bisphenol AD ​​novolac type epoxy resin; cycloaliphatic epoxy resins such as epoxidized products of dicyclopentadiene type phenolic resin; aromatic epoxy resins such as epoxidized products of naphthalene type phenolic resin; glycidyl ester type epoxy resins such as dimer acid glycidyl ester and triglycidyl ester; glycidyl amine type epoxy resins such as tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, tetraglycidyl metaxylylenediamine, and tetraglycidyl bisaminomethylcyclohexane; triglycidyl heterocyclic epoxy resins such as phenylmethyl isocyanurate; phloroglucinol triglycidyl ether, trihydroxybiphenyl triglycidyl ether, trihydroxyphenylmethane triglycidyl ether, glycerin triglycidyl ether, 2-[4-(2,3-epoxypropoxy)phenyl]-2-[4-[1,1-bis[4-(2,3-epoxypropoxy)phenyl]ethyl]phenyl]propane, and 1,3-bis[4-[1-[4-(2,3-epoxypropoxy)phenyl]-1-[4- Examples include trifunctional epoxy resins such as [1-[4-(2,3-epoxypropoxy)phenyl]-1-methylethyl]phenyl]ethyl]phenoxy]-2-propanol; tetrafunctional epoxy resins such as tetrahydroxyphenylethane tetraglycidyl ether, tetraglycidylbenzophenone, bisresorcinol tetraglycidyl ether, and tetraglycidoxybiphenyl; and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol.The 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol is commercially available as EHPE-3150 (manufactured by Daicel Corporation).

[0094] Furthermore, oligomeric or polymeric polyfunctional epoxy compounds can also be preferably used. Typical examples of oligomer or polymer type polyfunctional epoxy compounds include phenol novolac type epoxy compounds, brominated phenol novolac type epoxy compounds, orthocresol novolac type epoxy compounds, xylenol novolac type epoxy compounds, naphthol novolac type epoxy compounds, bisphenol A novolac type epoxy compounds, bisphenol AD ​​novolac type epoxy compounds, epoxidized dicyclopentadiene type phenol resins, and epoxidized naphthalene type phenol resins.

[0095] Other examples of suitable epoxy compounds include polyfunctional alicyclic epoxy compounds having alicyclic epoxy groups.

[0096] Specific examples of the alicyclic epoxy compound include 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, and trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate. epoxycyclohexane carboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), di(3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis(3,4-epoxycyclohexane carboxylate), dioctyl epoxycyclohexahydrophthalate, and di-2-ethylhexyl epoxycyclohexahydrophthalate, epoxy resins having a tricyclodecene oxide group, and compounds represented by the following formulas (b01-1) to (b01-5).

[0097] Among these specific examples of alicyclic epoxy compounds, alicyclic epoxy compounds represented by the following formulae (b01-1) to (b01-5) are preferred because they give cured products with high hardness.

[0098] [ka] (In formula (b01-1), Z 01 R represents a single bond or a linking group (a divalent group having one or more atoms). b01 ~R b018 are each independently a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group.

[0099] Linking group Z 01Examples of the alkyl group include divalent hydrocarbon groups, -O-, -O-CO-, -S-, -SO-, -SO2-, -CBr2-, -C(CBr3)2-, -C(CF3)2-, and -R b019 Examples include a divalent group selected from the group consisting of -O-CO- and a group in which a plurality of such groups are bonded together.

[0100] Linking group Z 01 Examples of the divalent hydrocarbon group include a linear or branched alkylene group having from 1 to 18 carbon atoms and a divalent alicyclic hydrocarbon group. Examples of the linear or branched alkylene group having from 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, a dimethylene group, and a trimethylene group. Examples of the divalent alicyclic hydrocarbon group include a cycloalkylene group (including a cycloalkylidene group) such as a 1,2-cyclopentylene group, a 1,3-cyclopentylene group, a cyclopentylidene group, a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, a 1,4-cyclohexylene group, and a cyclohexylidene group.

[0101] R b019 is an alkylene group having 1 to 8 carbon atoms, and is preferably a methylene group or an ethylene group.

[0102] [ka] (In formula (b01-2), R b01 ~R b018 R is a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. b02 and R b010 may be bonded to each other. b013 and R b016 may be bonded to each other to form a ring. a1 is either 0 or 1.)

[0103] The alicyclic epoxy compound represented by the formula (b01-2) includes m a1is 0, and is preferably a compound represented by the following formula (b01-2-1). [ka] (In formula (b01-2-1), R b01 ~R b012 R is a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. b02 and R b010 may be bonded to each other to form a ring.

[0104] [ka] (In formula (b01-3), R b01 ~R b010 R is a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. b02 and R b08 may be combined with each other.)

[0105] [ka] (In formula (b01-4), R b01 ~R b012 R is a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. b02 and R b010 may be combined with each other.)

[0106] [ka] (In formula (b01-5), R b01 ~R b012 is a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group.

[0107] In formulas (b01-1) to (b01-5), R b01 ~R b018is an organic group, the organic group is not particularly limited as long as it does not impair the object of the present invention, and may be a hydrocarbon group, a group consisting of carbon atoms and halogen atoms, or a group containing heteroatoms such as halogen atoms, oxygen atoms, sulfur atoms, nitrogen atoms, and silicon atoms in addition to carbon atoms and hydrogen atoms. Examples of halogen atoms include chlorine atoms, bromine atoms, iodine atoms, and fluorine atoms.

[0108] The organic group is preferably a hydrocarbon group, a group consisting of carbon atoms, hydrogen atoms, and oxygen atoms, a halogenated hydrocarbon group, a group consisting of carbon atoms, oxygen atoms, and halogen atoms, or a group consisting of carbon atoms, hydrogen atoms, oxygen atoms, and halogen atoms. When the organic group is a hydrocarbon group, the hydrocarbon group may be an aromatic hydrocarbon group, an aliphatic hydrocarbon group, or a group containing an aromatic skeleton and an aliphatic skeleton. The number of carbon atoms in the organic group is preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 5.

[0109] Specific examples of the hydrocarbon group include chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-icosyl; vinyl, 1-propenyl, 2-n-propenyl (allyl), and 1-n-butenyl. chain alkenyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, o-tolyl, m-tolyl, p-tolyl, α-naphthyl, β-naphthyl, biphenyl-4-yl, biphenyl-3-yl, biphenyl-2-yl, anthryl, and phenanthryl; and aralkyl groups such as benzyl, phenethyl, α-naphthylmethyl, β-naphthylmethyl, α-naphthylethyl, and β-naphthylethyl.

[0110] Specific examples of the halogenated hydrocarbon group include halogenated chain alkyl groups such as a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, a perfluorooctyl group, a perfluorononyl group, and a perfluorodecyl group; halogenated cyclohexyl groups such as a 2-chlorocyclohexyl group, a 3-chlorocyclohexyl group, a 4-chlorocyclohexyl group, a 2,4-dichlorocyclohexyl group, a 2-bromocyclohexyl group, a 3-bromocyclohexyl group, and a 4-bromocyclohexyl group; chloroalkyl groups; halogenated aryl groups such as a 2-chlorophenyl group, a 3-chlorophenyl group, a 4-chlorophenyl group, a 2,3-dichlorophenyl group, a 2,4-dichlorophenyl group, a 2,5-dichlorophenyl group, a 2,6-dichlorophenyl group, a 3,4-dichlorophenyl group, a 3,5-dichlorophenyl group, a 2-bromophenyl group, a 3-bromophenyl group, a 4-bromophenyl group, a 2-fluorophenyl group, a 3-fluorophenyl group, and a 4-fluorophenyl group; halogenated aralkyl groups such as a 2-chlorophenylmethyl group, a 3-chlorophenylmethyl group, a 4-chlorophenylmethyl group, a 2-bromophenylmethyl group, a 3-bromophenylmethyl group, a 4-bromophenylmethyl group, a 2-fluorophenylmethyl group, a 3-fluorophenylmethyl group, and a 4-fluorophenylmethyl group.

[0111] Specific examples of the group consisting of carbon atoms, hydrogen atoms, and oxygen atoms include chain hydroxy alkyl groups such as a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxy-n-propyl group, and a 4-hydroxy-n-butyl group; halogenated cycloalkyl groups such as a 2-hydroxycyclohexyl group, a 3-hydroxycyclohexyl group, and a 4-hydroxycyclohexyl group; a 2-hydroxyphenyl group, a 3-hydroxyphenyl group, a 4-hydroxyphenyl group, a 2,3-dihydroxyphenyl group, a 2,4-dihydroxyphenyl group, a 2,5-dihydroxyphenyl group, and a 2,5-dihydroxyphenyl group. hydroxyaryl groups such as phenyl, 2,6-dihydroxyphenyl, 3,4-dihydroxyphenyl, and 3,5-dihydroxyphenyl; hydroxyaralkyl groups such as 2-hydroxyphenylmethyl, 3-hydroxyphenylmethyl, and 4-hydroxyphenylmethyl; methoxy, ethoxy, n-propoxy, isopropoxy, n-butyloxy, isobutyloxy, sec-butyloxy, tert-butyloxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, and the like. chain alkoxy groups such as n-methyl-n-methyloxy, n-ethyl ... chain alkenyloxy groups such as an oxy group; aryloxy groups such as a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, an α-naphthyloxy group, a β-naphthyloxy group, a biphenyl-4-yloxy group, a biphenyl-3-yloxy group, a biphenyl-2-yloxy group, an anthryloxy group, and a phenanthryloxy group; aralkyloxy groups such as a benzyloxy group, a phenethyloxy group, an α-naphthylmethyloxy group, a β-naphthylmethyloxy group, an α-naphthylethyloxy group, and a β-naphthylethyloxy group;Alkoxyalkyl groups such as a methoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, a 2-methoxyethyl group, a 2-ethoxyethyl group, a 2-n-propoxyethyl group, a 3-methoxy-n-propyl group, a 3-ethoxy-n-propyl group, a 3-n-propoxy-n-propyl group, a 4-methoxy-n-butyl group, a 4-ethoxy-n-butyl group, and a 4-n-propoxy-n-butyl group; a methoxymethoxy group, an ethoxymethoxy group, an n-propoxymethoxy group, a 2-methoxyethoxy group, a 2-ethoxyethoxy group, and a 2-n-propoxyethoxy group. alkoxyalkoxy groups such as a 3-methoxy-n-propoxy group, a 3-ethoxy-n-propoxy group, a 3-n-propoxy-n-propoxy group, a 4-methoxy-n-butyloxy group, a 4-ethoxy-n-butyloxy group, and a 4-n-propoxy-n-butyloxy group; alkoxyaryl groups such as a 2-methoxyphenyl group, a 3-methoxyphenyl group, and a 4-methoxyphenyl group; alkoxyaryloxy groups such as a 2-methoxyphenoxy group, a 3-methoxyphenoxy group, and a 4-methoxyphenoxy group; a formyl group, an acetyl group, a propionyl group, aliphatic acyl groups such as benzoyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, and decanoyl groups; aromatic acyl groups such as benzoyl, α-naphthoyl, and β-naphthoyl groups; methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butyloxycarbonyl, n-pentyloxycarbonyl, n-hexylcarbonyl, n-heptyloxycarbonyl, n-octyloxycarbonyl, n-nonyloxycarbonyl, and n-decyloxycarbonyl groups; chain alkyloxycarbonyl groups such as an alkyloxy group; aryloxycarbonyl groups such as a phenoxycarbonyl group, an α-naphthoxycarbonyl group, and a β-naphthoxycarbonyl group; aliphatic acyloxy groups such as a formyloxy group, an acetyloxy group, a propionyloxy group, a butanoyloxy group, a pentanoyloxy group, a hexanoyloxy group, a heptanoyloxy group, an octanoyloxy group, a nonanoyloxy group, and a decanoyloxy group; aromatic acyloxy groups such as a benzoyloxy group, an α-naphthoyloxy group, and a β-naphthoyloxy group;

[0112] R b01 ~R b018 are each independently preferably a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. In particular, R b01 ~R b018 More preferably, all of are hydrogen atoms.

[0113] In formulas (b01-2) to (b01-5), R b01 ~R b018 is R in formula (b01-1) b01 ~R b018 In formula (b01-2) and formula (b01-4), R b02 and R b010 When these are bonded to each other, in formula (b01-2), R b013 and R b016 are bonded to each other, and in formula (b01-3), R b02 and R b08 Examples of the divalent group formed when these groups bond to each other include -CH2- and -C(CH3)2-.

[0114] Among the alicyclic epoxy compounds represented by formula (b01-1), specific examples of suitable compounds include alicyclic epoxy compounds represented by the following formulas (b01-1a), (b01-1b), and (b01-1c), 2,2-bis(3,4-epoxycyclohexane-1-yl)propane [=2,2-bis(3,4-epoxycyclohexyl)propane], etc. [ka]

[0115] Among the alicyclic epoxy compounds represented by formula (b01-2), specific examples of suitable compounds include alicyclic epoxy compounds represented by the following formulas (b01-2a) and (b01-2b): [ka]

[0116] Among the alicyclic epoxy compounds represented by formula (b01-3), specific examples of suitable compounds include S-spiro[3-oxatricyclo[3.2.1.0 2,4 ]octane-6,2'-oxirane] and the like.

[0117] Among the alicyclic epoxy compounds represented by formula (b01-4), specific examples of suitable compounds include 4-vinylcyclohexene dioxide, dipentene dioxide, limonene dioxide, 1-methyl-4-(3-methyloxiran-2-yl)-7-oxabicyclo[4.1.0]heptane, etc.

[0118] Among the alicyclic epoxy compounds represented by formula (b01-5), a specific example of a suitable compound is 1,2,5,6-diepoxycyclooctane.

[0119] Furthermore, a compound represented by the following formula (b1-I) can be suitably used as the epoxy compound. [ka] (In formula (b1-I), X b1 , X b2 , and X b3 are each independently a hydrogen atom or an organic group which may contain an epoxy group, and X b1 , X b2 , and X b3 The total number of epoxy groups contained in

[0120] The compound represented by the above formula (b1-I) is preferably a compound represented by the following formula (b1-II): [ka] (In formula (b1-II), R b20 ~R b22represents a linear, branched, or cyclic alkylene group, an arylene group, -O-, -C(=O)-, -NH-, or a group consisting of a combination thereof, and may be the same or different. 1 ~E 3 is at least one substituent selected from the group consisting of an epoxy group, an oxetanyl group, an ethylenically unsaturated group, an alkoxysilyl group, an isocyanate group, a blocked isocyanate group, a thiol group, a carboxy group, a hydroxyl group, and a succinic anhydride group, or a hydrogen atom, provided that E 1 , E 2 , and E 3 The total number of epoxy groups contained in

[0121] In formula (b1-II), R b20 and E 1 , R b21 and E 2 , and R b22 and E 3 Preferably, at least two of the groups represented by the formula (b1-IIa) are each a group represented by the following formula (b1-IIa), and more preferably, all of the groups are each a group represented by the following formula (b1-IIa). Preferably, multiple groups represented by formula (b1-IIa) bonded to one compound are the same group. -LC a (b1-IIa) In formula (b1-IIa), L represents a linear, branched, or cyclic alkylene group, an arylene group, —O—, —C(═O)—, —NH—, or a group formed by a combination thereof; a is an oxiranyl group (epoxy group). In formula (b1-IIa), L and C a may be bonded to form a cyclic structure.)

[0122] In formula (b1-IIa), the linear, branched, or cyclic alkylene group represented by L is preferably an alkylene group having from 1 to 10 carbon atoms, and the arylene group represented by L is preferably an arylene group having from 5 to 10 carbon atoms. In formula (b1-IIa), L is preferably a linear alkylene group having from 1 to 3 carbon atoms, a phenylene group, -O-, -C(=O)-, -NH-, or a group formed by a combination thereof, and is preferably at least one of a linear alkylene group having from 1 to 3 carbon atoms, such as a methylene group, and a phenylene group, or a group formed by a combination of any of these with at least one of -O-, -C(=O)-, and NH-.

[0123] In formula (b1-IIa), L and C a Examples of the case where a branched alkylene group and an epoxy group are bonded to form a cyclic structure (a structure having an epoxy group with an alicyclic structure) include organic groups represented by the following formulas (b1-IIb) to (b1-IId). [ka] (In formula (b1-IIb), R b23 is a hydrogen atom or a methyl group.

[0124] Examples of the compound represented by formula (b1-II) include, but are not limited to, epoxy compounds having an oxiranyl group or an alicyclic epoxy group. [ka]

[0125] [ka]

[0126] Furthermore, a siloxane compound having two or more glycidyl groups in the molecule (hereinafter also referred to simply as "siloxane compound") can be suitably used as the epoxy compound.

[0127] The siloxane compound is a compound having a siloxane skeleton composed of siloxane bonds (Si—O—Si) and two or more glycidyl groups in the molecule.

[0128] Examples of the siloxane skeleton in the siloxane compound include a cyclic siloxane skeleton and a cage-type or ladder-type polysilsesquioxane skeleton.

[0129] Of the siloxane compounds, compounds having a cyclic siloxane skeleton represented by the following formula (b1-III) (hereinafter, sometimes referred to as "cyclic siloxane") are preferred. [ka]

[0130] In formula (b1-III), R b24 , and R b25 represents a monovalent group or alkyl group containing an epoxy group, provided that x1 R in the compound represented by formula (b1-III) b24 and x1 R b25 At least two of the x1 groups are monovalent groups containing an epoxy group. In addition, x1 in formula (b1-III) represents an integer of 3 or more. In addition, in the compound represented by formula (b1-III), b24 , R b25 may be the same or different. b24 may be the same or different. b25 may be the same or different. Examples of the alkyl group include linear or branched alkyl groups having 1 to 18 carbon atoms (preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0131] In formula (b1-III), x1 represents an integer of 3 or more, and preferably an integer of 3 or more and 6 or less in terms of excellent crosslinking reactivity when forming a cured film. The number of epoxy groups contained in the siloxane compound molecule is 2 or more, and from the viewpoint of excellent crosslinking reactivity when forming a cured film, 2 to 6 is preferred, and 2 to 4 is particularly preferred.

[0132] The monovalent group containing an epoxy group includes an alicyclic epoxy group and -D A -OR b26 A glycidyl ether group [D A represents an alkylene group, and R b26 represents a glycidyl group] is preferred, an alicyclic epoxy group is more preferred, and an alicyclic epoxy group represented by the following formula (b1-IIIa) or the following formula (b1-IIIb) is even more preferred. A Examples of the (alkylene group) include linear or branched alkylene groups having 1 to 18 carbon atoms, such as methylene, methylmethylene, dimethylmethylene, dimethylene, and trimethylene. [ka] (In the above formula (b1-IIIa) and formula (b1-IIIb), D 1 and D 2 each independently represents an alkylene group, and ms represents an integer of 0 or more and 2 or less.

[0133] In addition to the siloxane compound represented by formula (b1-III), the varnish composition may contain, as the epoxy compound, a compound having a siloxane skeleton, such as an alicyclic epoxy group-containing cyclic siloxane, an alicyclic epoxy group-containing silicone resin described in JP-A-2008-248169, and an organopolysilsesquioxane resin having at least two epoxy functional groups per molecule described in JP-A-2008-19422.

[0134] More specifically, the siloxane compound may be a cyclic siloxane having two or more glycidyl groups in the molecule, as represented by the following formula: Furthermore, as the siloxane compound, for example, commercially available products such as "X-40-2670," "X-40-2701," "X-40-2728," "X-40-2738," and "X-40-2740" (all manufactured by Shin-Etsu Chemical Co., Ltd.) may be used.

[0135] [ka]

[0136] [ka]

[0137] The content of the monomer compound (B) in the varnish composition is not particularly limited as long as it does not impair the object of the present invention. The content of the monomer compound (B) in the varnish composition is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 40 parts by mass, and particularly preferably 1 to 25 parts by mass, based on 100 parts by mass of the varnish composition excluding the mass of the solvent (S) described below.

[0138] The varnish composition preferably contains a photoinitiator (C). When the polyimide resin (A) has a radical polymerizable group, a photoradical polymerization initiator (C1) may be used as the photoinitiator (C). When the polyimide resin (A) has a cationically polymerizable group, a photocationic polymerization initiator (C2) may be used as the photoinitiator (C). The photoinitiator (C) is not particularly limited, and any conventionally known photopolymerization initiator can be used.

[0139] Specific examples of the photoradical polymerization initiator (C1) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis( 4-Dimethylaminophenyl) ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, O-acetyl-1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone oxime, (9-ethyl-6-nitro-9H-carbazol-3-yl)[4-(2-methoxy-1-methylethoxy)-2-methylphenyl]methanone O-acetyl oxime, 2- (Benzoyloxyimino)-1-[4-(phenylthio)phenyl]-1-octanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-benzoyl-4'-methyldimethyl sulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 4-dimethylamino-2-ethylhexylbenzoic acid, 4-dimethylamino-2-isoamylbenzoic acid, benzyl-β-methoxyethyl acetal, benzyl dimethyl Ketal, 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, methyl o-benzoylbenzoate, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 1-chloro-4-propoxythioxanthone, thioxanthene, 2-chlorothioxanthene, 2,4-diethylthioxanthene, 2-methylthioxanthene, 2-isopropylthioxanthene, 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-Diphenylanthraquinone, azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)-imidazolyl dimer, benzophenone, 2-chlorobenzophenone, p,p'-bisdimethylaminobenzophenone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone Benzophenone, benzil, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone acetophenone, p-tert-butyldichloroacetophenone, α,α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, pentyl-4-dimethylaminobenzoate, 9-phenylacridine, 1,7-bis-(9-acridinyl)heptane, 1,5-bis-(9-acridinyl)pentane, 1,3-bis-(9-acridinyl)propane, p-methoxytriazine, 2,4,6-tris(trichloromethyl)-s-triazine, 2-methyl-4,6- Bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(furan-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-diethylamino-2-methylphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxyphenyl)-4,Examples of photopolymerization initiators include 6-bis(trichloromethyl)-s-triazine, 2-(4-ethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-n-butoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine, and 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine. These photopolymerization initiators can be used alone or in combination of two or more.

[0140] The cationic photopolymerization initiator (C2) typically includes onium salts, such as oxonium salts, ammonium salts, phosphonium salts, sulfonium salts, and iodonium salts, with sulfonium salts and iodonium salts being preferred, and sulfonium salts being more preferred.

[0141] The content of the photoinitiator (C) in the varnish composition is not particularly limited as long as the varnish composition has the desired photolithography properties. The content of the photoinitiator (C) in the varnish composition is typically preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the total of the mass of the polyimide resin (A) and the mass of the monomer compound (B).

[0142] The varnish composition contains an organic solvent (S). The type of organic solvent (S) is not particularly limited as long as it dissolves the polyimide resin (A) and other components well. In terms of good solubility of the polyimide resin (A), the organic solvent (S) preferably contains one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylcaprolactam, N,N,N',N'-tetramethylurea, cyclopentanone, and cyclohexanone. The content of these preferable organic solvents in the organic solvent (S) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0143] The varnish composition may contain various additives other than the components described above, as needed. Examples of additives include colorants, dispersants, sensitizers, adhesion promoters, antioxidants, UV absorbers, anti-aggregation agents, antifoaming agents, surfactants, etc. The varnish composition may also contain various fillers or reinforcing materials, as needed. The amount of each additive used is not particularly limited as long as it does not impair the object of the present invention, and may be appropriately adjusted within a range of, for example, 0.001% by mass to 60% by mass, preferably 0.05% by mass to 5% by mass, based on the mass of the solid content of the varnish composition. The amount of the filler or reinforcing material used is not particularly limited as long as it does not impair the object of the present invention. The amount of the filler or reinforcing material used is typically 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 even more preferably 10% by mass or more and 100% by mass or less, based on the mass of the polyamic acid (A).

[0144] <Polyimide film manufacturing method> The varnish composition described above is applied to a desired substrate to form a coating film, and then at least a portion of the organic solvent (S) is removed from the coating film to form a polyimide film. That is, a coating step of applying the varnish composition to a substrate to form a coating film; an organic solvent removing step of removing at least a portion of the organic solvent (S) from the coating film; The polyimide film is produced by a method comprising:

[0145] The method for applying the varnish composition to a substrate is not particularly limited. For example, the varnish composition can be applied to a substrate to a desired thickness using a contact transfer type coating device such as a roll coater, reverse coater, bar coater, or slit coater, or a non-contact type coating device such as a spinner (rotary coating device) or curtain flow coater, to form a coating film.

[0146] After forming a coating film of the varnish composition by the above method, the coating film is baked to remove the organic solvent (S), thereby forming a polyimide film. The baking temperature is appropriately determined taking into consideration the boiling point of the organic solvent (S), the heat resistance of the polyimide resin, etc. Baking may be performed at a low temperature under reduced pressure.

[0147] The baking method is not particularly limited, and may be, for example, any of (i) a method of drying using a hot plate at a temperature of 80°C to 120°C (preferably 85°C to 100°C, more preferably 85°C to 95°C) for 60 seconds to 500 seconds, (ii) a method of leaving the substrate at room temperature for several hours to several days, or (iii) a method of placing the substrate in a hot air heater or an infrared heater for several tens of minutes to several hours to remove the organic solvent (S).

[0148] The coating film formed as described above may be post-baked after removing the organic solvent (S). The upper limit of the temperature for post-baking is, for example, preferably 300° C. or lower, more preferably 280° C. or lower. The lower limit of the temperature is preferably 120° C. or higher, more preferably 130° C. or higher.

[0149] The thickness of the polyimide film formed as described above is not particularly limited and is determined appropriately depending on the application. The thickness of the polyimide film is typically preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0150] When the varnish composition contains a photoinitiator (C), a patterned polyimide film can be obtained by forming a coating film by the above-mentioned method, and then exposing and developing the coating film. That is, a coating step of applying a varnish composition containing a photoinitiator (C) onto a substrate to form a coating film; an organic solvent removing step of removing at least a portion of the organic solvent (S) from the coating film; a patterning step of exposing and developing the coating film from which at least a portion of the organic solvent (S) has been removed; A patterned polyimide film is produced by a method comprising:

[0151] In the above-mentioned method for producing a patterned polyimide film, the application of the varnish composition and the heating of the applied film to remove the organic solvent (S) are carried out according to the above-mentioned method.

[0152] The conditions for exposing the varnish composition to light are not particularly limited as long as the curing proceeds satisfactorily. The exposure is carried out by irradiating the varnish composition with active energy rays such as ultraviolet light or excimer laser light. The amount of energy radiation to be irradiated is not particularly limited, but is preferably 30 mJ / cm. 2 More than 5000mJ / cm 2 After exposure, the exposed coating film may be baked in the same manner as in the heating after coating.

[0153] The developing method is not particularly limited, and may be, for example, a dipping method, a spray method, etc. Specific examples of the developing solution include the organic solvent (S) that may be contained in the varnish composition.

[0154] After development, the developed coating film is optionally rinsed with pure water or baked to obtain a patterned polyimide film. The baking conditions after development are, for example, preferably 150° C. or higher and 280° C. or lower, and more preferably 180° C. or higher and 230° C. or lower. The baking time after development is, for example, preferably 5 minutes or higher and 12 hours or lower, more preferably 10 minutes or higher and 6 hours or lower, and particularly preferably 30 minutes or higher and 1 hour or higher. [Example]

[0155] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0156] Example 1 A three-neck flask was charged with 15.57 g of 4,4'-(4-aminophenyloxy)biphenyl (hereinafter referred to as BPAB) as a diamine component, 6.43 g of 3,5-diaminobenzoic acid (hereinafter referred to as DABA), and 250 g of NMP. The contents of the flask were then stirred to dissolve the BPAB and DABA in the NMP. 40 g of 2,2-bis[4-(3,4-dicarboxyphenyloxy)phenyl]propane dianhydride (hereinafter referred to as BPADA) as a tetracarboxylic dianhydride component was then added to the solution in the flask, and the reaction solution in the flask was stirred at room temperature for 24 hours. 0.88 g of 5-norbornene-2,3-dicarboxylic anhydride as an end-capping agent was then added to the reaction solution, and the reaction solution was stirred at room temperature for 4 hours to obtain a polyamic acid. The numerical values ​​in the brackets to the right of the formula below indicate the molar ratio (mol %) of each structural unit in the resin.

[0157] <Polyamic acid generation> [ka]

[0158] 33 g of carbodiimidazole was added to the reaction solution containing the polyamic acid, and the reaction solution was stirred at room temperature for 4 hours to convert the polyamic acid into a polyimide resin. The stirred reaction solution was dropped into 5 kg of water to form a precipitate. The precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of water and then dried under reduced pressure at 50°C to obtain a polyimide resin having a carboxy group, which is composed of the structural unit shown in the following formula:

[0159] <Imidization> [ka]

[0160] The obtained polyimide resin having carboxy groups, 8.25 g of 2-hydroxyethyl methacrylate, 25.0 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (WSC-HCl), and 5.15 g of 4-dimethylaminopyridine (DMAP) were added to 250 g of NMP in a three-neck flask, and the reaction solution was stirred at room temperature for 6 hours. The stirred reaction solution was added dropwise to 2 kg of methanol to form a precipitate. The precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of methanol and then dried under reduced pressure at 50°C to obtain a polyimide resin having a methacryloyl group at the side chain end, which is composed of the structural unit shown in the following formula: Regarding the obtained polyimide resin 1 H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin.

[0161] <Methacryloyl group introduction> [ka]

[0162] Example 2 A polyimide resin having the following formula structure was synthesized in the same manner as in Example 1, except that the amount of BPAB used was changed to 21.80 g, the amount of DABA used was changed to 3.86 g, and the amount of 2-hydroxyethyl methacrylate used was changed to 4.95 g. Regarding the obtained polyimide resin 1 H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0163] Example 3 A polyimide resin having the following formula structure was synthesized in the same manner as in Example 1, except that the amount of BPAB used was changed to 24.19 g, the amount of DABA used was changed to 2.57 g, and the amount of 2-hydroxyethyl methacrylate used was changed to 3.30 g. Regarding the obtained polyimide resin 1 H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0164] Example 4 A polyimide resin having the following structure was synthesized in the same manner as in Example 1, except that 15.57 g of BPAB was changed to 19.18 g of 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl (TFDB below), the amount of DABA used was changed to 3.86 g, the amount of 2-hydroxyethyl methacrylate used was changed to 4.95 g, and the amount of WSC-HCl used was changed to 13.62 g. Regarding the obtained polyimide resin 1 H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0165] [ka]

[0166] Example 5 A polyimide resin having the structure shown below was synthesized in the same manner as in Example 1, except that 15.57 g of BPAB was changed to 30.68 g of 2,2-bis[4-(4-aminophenyloxy)phenyl]-1,1,1,3,3,3-hexafluorophenylpropane (hereinafter referred to as HF-BPAA), the amount of DABA used was changed to 3.86 g, the amount of 2-hydroxyethyl methacrylate used was changed to 4.95 g, and the amount of WSC-HCl used was changed to 13.62 g. Regarding the obtained polyimide resin 1 H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0167] [ka]

[0168] Example 6 A polyimide resin having the structure shown below was synthesized in the same manner as in Example 1, except that 40 g of BPADA was changed to 40 g of 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride (hereinafter referred to as 6FDA), 15.57 g of BPAB was changed to 35.94 g of HF-BPAA, the amount of DABA used was changed to 4.52 g, the amount of carbodiimidazole used was changed to 28.17 g, the amount of 2-hydroxyethyl methacrylate used was changed to 5.80 g, and the amount of WSC-HCl used was changed to 15.95 g. [ka]

[0169] [ka]

[0170] Example 7 A polyimide resin having the structure shown below was synthesized in the same manner as in Example 1, except that 40 g of BPADA was changed to 40 g of 3,3',4,4'-tetracarboxydiphenyl ether dianhydride (hereinafter referred to as ODPA), 15.57 g of BPAB was changed to 51.47 g of HF-BPAA, the amount of DABA used was changed to 6.47 g, the amount of carbodiimidazole used was changed to 28.17 g, the amount of 2-hydroxyethyl methacrylate used was changed to 5.80 g, and the amount of WSC-HCl used was changed to 15.95 g. [ka]

[0171] [ka]

[0172] Example 8 A three-neck flask was charged with 24.91 g of BPAB (diamine component), 5.89 g of 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, and 250 g of NMP. The contents of the flask were then stirred to dissolve the diamine component in the NMP. Then, 40 g of BPADA was added to the solution in the flask, and the reaction mixture in the flask was stirred at room temperature for 24 hours to produce polyamic acid.

[0173] <Polyamic acid generation> [ka]

[0174] 33 g of carbodiimidazole was added to the reaction solution containing the polyamic acid, and the reaction solution was stirred at room temperature for 4 hours to convert the polyamic acid into a polyimide resin. The stirred reaction solution was dropped into 5 kg of water to form a precipitate. The precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of water and then dried under reduced pressure at 50°C to obtain a polyimide resin having a phenolic hydroxyl group, which is composed of the structural unit shown in the following formula:

[0175] <Imidization> [ka]

[0176] The obtained polyimide resin having a phenolic hydroxyl group, 5.30 g of methacrylic acid chloride, 4.50 g of triethylamine, and 300 g of NMP were added to a three-necked flask, and the reaction solution in the flask was stirred at room temperature for 6 hours. The stirred reaction solution was added dropwise to 2 kg of methanol to form a precipitate. The precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of methanol and then dried under reduced pressure at 50°C to obtain a polyimide resin having a methacryloyl group at the side chain end, which is composed of the structural unit shown in the following formula: Regarding the obtained polyimide resin 1H-NMR measurement confirmed imidization by the disappearance of the peak corresponding to the amide bond, and the integral ratio of the total aromatics and the integral ratio of the double bonds confirmed that the theoretical amount of methacryloyl groups had been introduced into the polyimide resin.

[0177] <Methacryloyl group introduction> [ka]

[0178] Comparative Example 1 A polyimide resin having the following structure was synthesized in the same manner as in Example 1, except that 40 g of BPADA was changed to 40 g of 6FDA, 15.57 g of BPAB was changed to 22.48 g of TFDB, the amount of DABA used was changed to 4.52 g, the amount of carbodiimidazole used was changed to 28.17 g, the amount of 2-hydroxyethyl methacrylate used was changed to 5.80 g, and the amount of WSC-HCl used was changed to 15.95 g.

[0179] [ka]

[0180] Comparative Example 2 A photosensitive polyamide resin consisting of the following structural units was obtained by the same method as in Synthesis Example 1 described in WO 2018 / 003726. The following polyamide resin generates a polyimide resin by ring closure accompanied by elimination of 2-hydroxyethyl methacrylate upon heating. [ka]

[0181] [Examples 9 to 19, Comparative Example 3, or Comparative Example 4] 100 parts by mass of a polyimide resin or polyamide resin of the type shown in Table 1 was dissolved in NMP to a concentration of 20% by mass. 5 parts by mass of Irgacure OXE01 (manufactured by BASF Japan Ltd.), an oxime ester photopolymerization initiator, and 0.5 parts by mass of pentaerythritol tetrakis(3-mercaptobutyrate) (Karenz MT PE1 (manufactured by Showa Denko K.K.)), a chain transfer agent, were added to the resulting solution to obtain a photosensitive composition for each example. The photosensitive compositions of Examples 12 to 14 further contained photopolymerizable monomers of the types and amounts shown in Table 1. The photopolymerizable monomers shown in Table 1 are as follows. M1: Dimethyloltricyclodecane diacrylate M2: Dipentaerythritol hexaacrylate

[0182] The obtained photosensitive composition was used to evaluate the imidization rate when formed into a film, the photosensitivity, and the dielectric properties by measuring the dielectric properties according to the following methods. The results of the photosensitivity evaluation and the dielectric properties evaluation are shown in Table 1.

[0183] <Film formation and imidization rate evaluation> In Examples 9 to 19 and Comparative Example 3, the photosensitive composition was applied to a silicon wafer using a spin coater, and the resulting coating film was then exposed to a high-pressure mercury lamp at an exposure dose of 2000 mJ / cm 2 . 2 The exposed coating film was heated at 180°C for 1 hour to form a polyimide resin film. The formed polyimide resin film was peeled off from the silicon wafer using a 1% by mass aqueous solution of hydrofluoric acid to obtain a polyimide resin film. The thickness of the obtained polyimide resin film was 20 μm.

[0184] The imidization rates of the polyimide resin films obtained by the above method using the NMP solutions of the polyimide resins obtained in Examples 9 to 19 and Comparative Example 3 were all 95% or higher. For the photosensitive composition of Comparative Example 4 containing the photosensitive polyamide resin obtained in Comparative Example 2, exposure under the above conditions and heating at 180°C for 1 hour did not achieve an imidization rate of 95% or more, but further heating at 350°C for 1 hour achieved an imidization rate of 95% or more. The imidization ratio was measured by the following method. First, the film obtained by the above method was heated at 350°C for 4 hours, and then the FT-IR spectrum of the heated film was measured. Next, the FT-IR spectrum of the film obtained by the above method but not heated at 350°C was measured. Wavenumber 1380 cm in the FT-IR spectrum of the film heated at 350 °C -1 The height H of the imide stretching vibration peak at 01 and the height of the aromatic peak H 02 From this, the ratio of the two, H 01 / H 02 The value of was calculated. Next, in the FT-IR spectrum of the film not heated at 350 °C, the wave number 1380 cm -1 The height H of the imide stretching vibration peak at 11 and the height of the aromatic peak H 12 From this, the ratio of the two, H 11 / H 12 The value of was calculated. H 01 / H 02 and the value of H 11 / H 12 The imidization rate was determined from the value of 1 / (2) and 1 / (3) according to the following formula. Imidization rate (%) = (H 11 / H 12 ) / (H 01 / H 02 ) x 100

[0185] <Photosensitivity evaluation> The photosensitive composition was spin-coated on a copper wafer to form a coating film, which was then baked for 300 seconds at 80° C. The rotation speed during spin-coating was adjusted so that the coating film after baking had a thickness of 10 μm. The baked coating film was exposed to light at a dose of 100 mJ / cm through a negative mask for hole formation having approximately square openings of 50 μm × 50 μm. 2 to 4000mJ / cm 2 The exposure was performed at a focus of 0 μm. The exposed coating film was developed by immersing it in cyclopentanone for 60 seconds. The coating film after development was observed using a scanning electron microscope (SEM). If a hole with an approximately square opening measuring 50 μm × 50 μm was formed, it was judged as ◯, and if not, it was judged as ×.

[0186] <Dielectric property measurement> The dielectric constant (ε) and dielectric loss tangent (tanδ) of the sample were measured using the same method as described above, except that the film thickness was changed to 10 μm. The dielectric constant (ε) and dielectric loss tangent (tanδ) of the sample were measured using the method described in "Study on Evaluation of Millimeter-Wave Complex Permittivity of Photosensitive Insulating Films Using a Cylindrical Cavity Resonator Method" (Kohei Takahagi (Utsunomiya University), Kazuaki Ebisawa (Tokyo Ohka Kogyo Co., Ltd.), Yoshinori Kogami (Utsunomiya University), and Takashi Shimizu (Utsunomiya University) in the Technical Report of the Institute of Electronics, Information and Communication Engineers, Vol. 118, No. 506, MW2018-158, pp. 13-18, March 2019). Measurements were performed using a network analyzer HP8510C (Keysight Corporation) using the cavity resonator method at room temperature of 25°C, humidity of 50%, a frequency of 36 GHz, and a sample thickness of 10 μm. The dielectric constant value was judged as ◯ when it was less than 3.00, and as x when it was 3.00 or more. A dielectric loss tangent value of less than 0.01 was judged as ◯, and a dielectric loss tangent value of 0.01 or more was judged as x.

[0187] [Table 1]

[0188] According to Examples 9 to 11, it can be seen that polyimide resins containing a structural unit of the specific structure represented by the above-mentioned formula (A1a) and having a polymerizable group such as a methacryloyl group dissolve well in organic solvents such as NMP, exhibit good photosensitivity, and give polyimide resin films with excellent dielectric properties. On the other hand, according to Comparative Examples 3 and 4, it is found that a polyimide resin having a polymerizable group but not containing a structural unit having the specific structure represented by the above formula (A1) gives a polyimide resin film having poor dielectric properties.

Claims

1. A varnish composition comprising a polyimide resin (A) and an organic solvent (S), The polyimide resin (A) is The following formula (A1a): 【Chemical 1】 (In formula (A1a), X １ is a divalent organic group, and Y １ is a tetravalent organic group. １ does not contain a divalent organic group having a polyorganosiloxane structure or a structure derived from dimer diamine, and Y １ is a sulfonyl group (-SO ２ -) does not contain a tetravalent organic group. It is a polyimide resin consisting only of molecular chains containing structural units represented by The X １ and the divalent organic group as Y １ At least one of the tetravalent organic groups represented by the formula (a1): 【Chemistry 2】 (In formula (a1), R ａ１ and R ａ２ are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; n1 and n2 are each independently an integer of 0 to 4; R ａ３ and R ａ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a phenyl group; R ａ３ and R ａ４ may be bonded to each other to form a ring.) or a polyimide resin having a partial structure represented by or a molecular chain including a structural unit represented by formula (A1a); The following formula (A1e): 【Chemistry 3】 (In formula (A1e), X ４ is a divalent organic group that does not have the partial structure represented by formula (a1), and Y ２ is a tetravalent organic group that does not have the partial structure represented by formula (a1). ４ does not contain a divalent organic group having a polyorganosiloxane structure or a structure derived from dimer diamine, and Y ２ is a sulfonyl group (-SO ２ -) does not contain a tetravalent organic group. A molecular chain containing a constitutional unit represented by A polyimide resin comprising A varnish composition for pattern formation, wherein the structural unit represented by formula (A1e) does not have a partial structure represented by formula (a1), and the molecular chain contains a radically polymerizable group.

2. A varnish composition comprising a polyimide resin (A) and an organic solvent (S), The polyimide resin (A) is The following formula (A1a): 【Chemistry 4】 (In formula (A1a), X １ is a divalent organic group, and Y １ is a tetravalent organic group. １ does not contain a divalent organic group having a polyorganosiloxane structure or a structure derived from dimer diamine, and Y １ is a sulfonyl group (-SO ２ -) does not contain a tetravalent organic group. It consists only of molecular chains containing structural units represented by The X １ and the divalent organic group as Y １ At least one of the tetravalent organic groups represented by the formula (a1): 【Chemistry 5】 (In formula (a1), R ａ１ and R ａ２ are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; n1 and n2 are each independently an integer of 0 to 4; R ａ３ and R ａ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a phenyl group; R ａ３ and R ａ４ may be bonded to each other to form a ring.) It has a partial structure represented by the main chain terminals of the molecular chains are blocked; or a molecular chain including a structural unit represented by formula (A1a); The following formula (A1e): 【Chemistry 6】 (In formula (A1e), X ４ represents a divalent organic group that does not have the partial structure represented by formula (a1). and Y ２ is a tetravalent organic group that does not have the partial structure represented by formula (a1). But, X ４ The compound has a polyorganosiloxane structure and a structure derived from dimer diamine. does not contain a divalent organic group having Y ２ is a sulfonyl group (-SO ２ -) a tetravalent organic group Not included.) A molecular chain containing a constitutional unit represented by Including, the main chain terminal of the molecular chain is blocked, A varnish composition for pattern formation, wherein the structural unit represented by formula (A1e) does not have a partial structure represented by formula (a1), and the molecular chain contains a radically polymerizable group.

3. 2. The varnish composition for pattern formation according to claim 1, wherein the molecular chains are capped with an end-capping agent.

4. The molecular chain contains, as the structural unit represented by formula (A1a), the structural unit represented by formula (A1b): 【Chemistry 7】 (In formula (A1b), X ２ and X ３ each independently represents a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; Y ２ is a tetravalent organic group that does not have the partial structure represented by formula (a1), and R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as those in formula (a1). a structural unit represented by the following formula (A1c): 【Chemistry 8】 (In formula (A1c), X ４ is a divalent organic group that does not have the partial structure represented by formula (a1), and Y ３ and Y ４ are each independently a trivalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as those in formula (a1). 【Chemistry 9】 (In formula (A1d), X ５ and X ６ each independently represents a divalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; Y ５ and Y ６ are each independently a trivalent aromatic hydrocarbon group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, and a halogen atom; R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as those in formula (a1).

5. The polyimide resin contains a structural unit represented by the formula (A1c), and the X ４ The pattern-forming varnish composition according to claim 4, wherein

6. 6. The pattern-forming varnish composition according to claim 1, wherein the radical polymerizable group contains a (meth)acryloyl group.

7. 7. The pattern-forming varnish composition according to claim 1, further comprising a monomer compound (B), wherein the monomer compound (B) is a monomer compound having an ethylenically unsaturated double bond.

8. The pattern-forming varnish composition according to claim 7, wherein the monomer compound (B) is a polyfunctional monomer compound.

9. 9. The pattern-forming varnish composition according to claim 7, wherein the content of the monomer compound (B) is 0.1 parts by mass or more and 50 parts by mass or less, when the mass of the varnish composition excluding the mass of the organic solvent (S) is 100 parts by mass.

10. 10. The pattern-forming varnish composition according to claim 1, wherein the ratio of the mass of the polyimide resin (A) to the mass of the varnish composition is 5 mass% or more and 50 mass% or less.

11. 11. The varnish composition for pattern formation according to claim 1, wherein 80% by mass or more of the polyimide resin (A) is dissolved in the organic solvent (S) at 20°C.

12. The pattern-forming varnish composition according to any one of claims 1 to 11, wherein the organic solvent (S) comprises one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylcaprolactam, N,N,N',N'-tetramethylurea, cyclopentanone, and cyclohexanone.

13. The pattern-forming varnish composition according to any one of claims 1 to 12, which contains a photoinitiator (C).

14. a coating step of applying the varnish composition for pattern formation according to any one of claims 1 to 13 onto a substrate to form a coating film; an organic solvent removing step of removing at least a portion of the organic solvent (S) from the coating film.

15. a coating step of applying the pattern-forming varnish composition according to claim 13 onto a substrate to form a coating film; an organic solvent removing step of removing at least a portion of the organic solvent (S) from the coating film; a patterning step of exposing and developing the coating film from which at least a portion of the organic solvent (S) has been removed; A method for producing a patterned polyimide film, comprising:

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