Polyimide varnish, method for producing a polyimide film, and method for producing a patterned polyimide film

Abstract

To provide a polyimide varnish in which a polyimide resin is dissolved in an organic solvent, thereby providing a polyimide film with excellent dielectric properties in the high-frequency band; a method for producing a polyimide film using the aforementioned polyimide varnish; and a method for producing a patterned polyimide film using the aforementioned polyimide varnish. [Solution] We have found that a polyimide resin having a biphenyl skeleton of a specific structure in the main chain is readily soluble in organic solvents. The inventors prepare a polyimide varnish by dissolving such a polyimide resin in an organic solvent.

Description

[Technical Field]

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

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

[0003] Furthermore, in recent years, communication devices such as mobile phones have been increasingly using higher frequencies. Therefore, the insulating parts that insulate the metal wiring in communication devices also need to be able to handle these higher frequencies. Here, transmission loss increases with increasing frequency, and increased transmission loss leads to attenuation of the electrical signal. Therefore, reducing transmission loss is required to cope with higher frequencies. In this respect, polyimide resin exhibits low dielectric loss tangent and low dielectric constant in the high-frequency band, resulting in excellent high-frequency characteristics. For this reason, polyimide resin is attracting attention as a material that can reduce transmission loss in various substrates and devices used in the high-frequency band.

[0004] As a polyimide resin exhibiting such excellent high-frequency properties, a polyimide resin has been proposed that is obtained by reacting an aromatic tetracarboxylic dianhydride of a specific structure with diaminoquaternium to produce a polyamic acid, which is then imidized at high temperature (Patent Document 1). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-080315 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, as described above, in Patent Document 1, a varnish containing polyamic acid, which is a precursor, is applied, and then the applied film is heated at a high temperature to form the polyimide resin. Therefore, when manufacturing substrates or devices containing polyimide resin, there are significant limitations in the selection of materials used together with the polyimide resin from the viewpoint of heat resistance.

[0007] For the reasons described above, there is a demand for polyimide varnish, which is obtained by dissolving polyimide resin in an organic solvent. Using such a polyimide varnish, a polyimide film can be formed by applying the varnish to a substrate or the like, and then removing the organic solvent from the applied film. This method allows for the formation of a polyimide film without high-temperature heating.

[0008] The present invention has been made in view of the above problems, and aims to provide a polyimide varnish in which a polyimide resin is dissolved in an organic solvent and which gives a polyimide film with excellent dielectric properties in the high frequency band, a method for producing a polyimide film using the above-mentioned polyimide varnish, and a method for producing a patterned polyimide film using the above-mentioned polyimide varnish. [Means for solving the problem]

[0009] The inventors have discovered that polyimide resins having a biphenyl skeleton of a specific structure in the main chain are readily soluble in organic solvents. The inventors have found that the above problems can be solved by dissolving such polyimide resins in organic solvents to prepare polyimide varnish, and have completed the present invention. More specifically, the present invention provides the following:

[0010] A first aspect of the present invention is a polyimide varnish comprising a polyimide resin (A) containing a structural unit represented by the following formula (A1) in its molecular chain, and an organic solvent (S). [ka] (In formula (A1), X 1 and X 2 These are, independently, divalent organic groups, Y 1 R is a tetravalent organic group, a1 and R a2 Each of these is independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n1 and n2 are independently integers between 0 and 4.

[0011] A second aspect of the present invention is a coating step of applying a polyimide varnish according to the first aspect onto a substrate to form a coating film, An organic solvent removal step, which removes at least a portion of the organic solvent (S) from the coated film, This is a method for producing a polyimide film, which includes [the specified ingredient].

[0012] A third aspect of the present invention is a coating step of forming a coating film by applying a polyimide varnish according to the first aspect onto a substrate, comprising a polyimide resin (A) having radical polymerizable groups or cationic polymerizable groups on its molecular chain and a photoinitiator (C), An organic solvent removal step, which removes at least a portion of the organic solvent (S) from the coated film, A patterning step involves exposing and developing a coated film from which at least a portion of the organic solvent (S) has been removed. This is a method for producing a patterned polyimide film, which includes [the specified element]. [Effects of the Invention]

[0013] According to the present invention, there can be provided a polyimide varnish in which a polyimide resin is dissolved in an organic solvent and which provides a polyimide film excellent in dielectric properties in a high frequency band, a method for producing a polyimide film using the aforementioned polyimide varnish, and a method for producing a patterned polyimide film using the aforementioned polyimide varnish. MODE FOR CARRYING OUT THE INVENTION

[0014] <<Polyimide Varnish>> The polyimide varnish contains a polyimide resin (A) having a specific structure described later and an organic solvent (S). The polyimide resin (A) described later has excellent solubility in the organic solvent (S). Therefore, the polyimide varnish can be easily prepared as a solution of the polyimide resin (A) in the organic solvent (S). The essential and optional components that may be contained in the polyimide varnish are described below.

[0015] <Polyimide Resin (A)> The polyimide resin (A) includes a structural unit represented by the following formula (A1) in a molecular chain thereof. Chemical formula (In formula (A1), X 1 and X 2 are each independently a divalent organic group, Y 1 is a tetravalent organic group, 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, and n1 and n2 are each independently an integer of 0 to 4.)

[0016] The amount of the structural unit represented by formula (A1) in the polyimide resin (A) is not particularly limited as long as the polyimide resin (A) can form a polyimide varnish uniformly dissolved in the organic solvent (S). The content of the constituent unit represented by formula (A1) in the polyimide resin (A) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the mass of the polyimide resin (A).

[0017] In formula (A1), R a1 and R a2 Examples of alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups. Among these alkyl groups, methyl and ethyl groups are preferred, with methyl being more preferred. In formula (A1), R a1 and R a2 Examples of alkoxy groups having 1 to 4 carbon atoms include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, and tert-butyloxy groups. Among these alkoxy groups, methoxy and ethoxy groups are preferred, with methoxy groups being more preferred. In formula (A1), R a1 and R a2 Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Among these halogen atoms, chlorine and bromine are preferred.

[0018] In formula (A1), n1 and n2 are each an independent integer between 0 and 4. Because monomer compounds for producing polyamic acid, a precursor of polyimide resin (A), are readily available, n1 and n2 are each preferably integers between 0 and 2, and more preferably 0.

[0019] X in equation (A1) 1 and X 2 The divalent organic group as is is not particularly limited as long as it does not hinder the objectives of the present invention. 1 and X 2The divalent organic group may contain heteroatoms such as O, N, S, P, B, Si, and halogen atoms. The number of carbon atoms in the divalent organic group is preferably 1 to 50, and more preferably 1 to 20. The divalent organic group may be an aliphatic group, a group consisting of an aromatic group and an aliphatic group or heteroatom, or an aromatic group.

[0020] As a constituent unit represented by formula (A1), the constituent unit represented by the following formula (A1-a) is preferred because it allows for easy preparation of the polyimide resin (A) and the polyimide resin (A) has good solubility in organic solvents (S).

[0021] [ka] (In formula (A1-a), Y 1 , R a1 , R a2 n1 and n2 are the same as those in equation (A1), and X 3 and X 4 Each of these is an aromatic hydrocarbon group that may be independently substituted with one or more groups selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, and halogen atoms.

[0022] X in equation (A1-a) 3 and X 4 Each of these is a divalent aromatic hydrocarbon group that may be independently substituted with one or more groups selected from the group consisting of alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, and halogen atoms. Examples of alkyl groups having 1 to 4 carbon atoms as substituents include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups. Among these alkyl groups, methyl and ethyl groups are preferred, with methyl groups being more preferred. Examples of alkoxy groups having 1 to 4 carbon atoms as substituents include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, and tert-butyloxy groups. Among these alkoxy groups, methoxy and ethoxy groups are preferred, with methoxy groups being more preferred. Examples of halogen atoms used as substituents include fluorine, chlorine, bromine, and iodine. Among these halogen atoms, chlorine and bromine are preferred.

[0023] X 3 and X 4 The number of carbon atoms in the aromatic hydrocarbon group is not particularly limited; for example, 6 to 50 is preferred, and 6 to 20 is more preferred. Note that the number of carbon atoms in the aromatic hydrocarbon group mentioned above does not include the number of carbon atoms in substituents. X 3 and X 4 Preferred aromatic hydrocarbon groups include phenylene groups such as o-phenylene, m-phenylene, and p-phenylene groups; naphthalenediyl groups such as naphthalene-1,4-diyl, naphthalene-1,3-diyl, naphthalene-2,6-diyl, and naphthalene-2,7-diyl groups; and biphenyldiyl groups such as biphenyl-4,4'-diyl, biphenyl-3,4'-diyl, and biphenyl-3,3'-diyl groups.

[0024] X 3 and X 4 The preferred groups are p-phenylene, m-phenylene, naphthalene-1,4-diyl, and biphenyl-4,4'-diyl, more preferably p-phenylene and biphenyl-4,4'-diyl, and even more preferably p-phenylene.

[0025] Y in equation (A1) 1 Y is a tetravalent organic group. 1The tetravalent organic group is typically a tetravalent organic residue derived from a tetracarboxylic dianhydride, which is used as a raw material for polyamic acid, a precursor of polyimide resin (A). Examples of tetracarboxylic dianhydrides that give the tetravalent organic residue include compounds represented by the following formula (a1-1). Tetracarboxylic dianhydrides may be used individually or in combination of two or more. [ka] (In formula (a1-1), A 1 (This refers to a tetravalent organic group with 6 to 50 carbon atoms.)

[0026] In formula (a1-1), A 1 This is a tetravalent organic group having 6 to 50 carbon atoms, and may have one or more substituents in addition to the two -CO-O-CO- acid anhydride groups represented by formula (a1-1). Preferred examples of substituents include fluorine atoms, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, fluorinated alkyl groups having 1 to 6 carbon atoms, and fluorinated alkoxy groups having 1 to 6 carbon atoms. In addition, the compound represented by formula (a1-1) may contain a carboxyl 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 preferable that it be a perfluoroalkyl group or a perfluoroalkoxy group. The same applies to the substituents described above, as well as to the one or more substituents that the aromatic group may have on its aromatic ring, as described later.

[0027] A 1 The number of carbon atoms constituting the compound is more preferably 8 or more, and even more preferably 12 or more. Also, A 1 The number of carbon atoms constituting the compound is more preferably 40 or less, and even more preferably 30 or less. 1 This can be an aliphatic group, an aromatic group, or a group that combines these structures. 1In addition to carbon atoms and hydrogen atoms, it may also contain halogen atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. 1 If it contains an oxygen atom, a nitrogen atom, or a sulfur atom, the oxygen atom, nitrogen atom, or sulfur atom is a group selected from a nitrogen-containing heterocyclic group, -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO2-, -S-, and -SS-, A 1 It may be included as a group selected from -O-, -CO-, -SO-, -SO2-, -S-, and -SS-, A 1 It is preferable to give birth to them.

[0028] The tetracarboxylic dianhydride represented by formula (a1-1) can be appropriately selected from tetracarboxylic dianhydrides that have been conventionally used as raw materials for the synthesis of polyamic acids, provided that the aforementioned predetermined conditions are met. The tetracarboxylic dianhydride may be an aliphatic tetracarboxylic dianhydride or an aromatic tetracarboxylic dianhydride.

[0029] Examples of aliphatic tetracarboxylic dianhydrides include 2,2-bis(3,4-dicarboxy)propane dianhydride and bis(3,4-dicarboxy)methane dianhydride. Furthermore, aliphatic tetracarboxylic dianhydrides may contain alicyclic structures. These alicyclic structures may be polycyclic. Examples of polycyclic alicyclic structures include cross-linked alicyclic structures such as bicyclo[2.2.1]heptane. For example, a cross-linked alicyclic structure may be condensed with other cross-linked alicyclic structures and / or non-cross-linked alicyclic structures, or a cross-linked alicyclic structure may be linked with other cross-linked alicyclic structures and / or non-cross-linked alicyclic structures by spirobonds. When using aliphatic tetracarboxylic dianhydrides, there is a tendency to obtain cured products with excellent transparency using the composition.

[0030] Also, in equation (a1-1) A 1As the aliphatic group constituting the material, for example, a tetravalent group represented by the following formula (a2) can be used. When such a group is used, it tends to be easier to obtain a polyimide resin (A) with excellent transparency. Furthermore, since the raw material compounds are easy to purify, a in formula (a2) is preferably 5 or less, and more preferably 3 or less. Also, since the raw material compounds that give the structural units represented by formula (a1) have excellent chemical stability, a is preferably 1 or more, and more preferably 2 or more. In formula (a2), a is preferably 2 or 3. [ka] (In formula (a2), R a11 , R a12 , and R a13 Each of these is independently 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 between 0 and 12.

[0031] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 3,3',4,4'-oxybisphthalic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride.

[0032] Aromatic tetracarboxylic dianhydrides may also be compounds represented by the following general formulas (a1-2) to (a1-4). [ka]

[0033] In the above equations (a1-2) and (a1-3), R a01 , R a02 and R a03Each of these represents a divalent group consisting of an aliphatic group which may be substituted with a halogen, an oxygen atom, a sulfur atom, an aromatic group via one or more divalent elements, or a combination thereof. a02 and R a03 They may be the same or different. That is, R a01 , R a02 and R a03 This may include a carbon-carbon single bond, a carbon-oxygen-carbon ether bond, or a halogen element (fluorine, chlorine, bromine, iodine). Examples of compounds represented by formula (a1-2) include 2,2-bis(3,4-dicarboxyphenoxy)propane dianhydride and 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride.

[0034] Furthermore, in the above formula (a1-4), R a04 , R a05 R represents a monovalent substituent consisting of an aliphatic group which may be substituted with a halogen, an aromatic group via one or more divalent elements, a halogen, or a combination thereof. a04 , and R a05 These may be the same or different. As compounds represented by formula (a1-4), difluoropyromellitic dianhydride and dichloropyromellitic dianhydride can also be used.

[0035] Furthermore, it is preferable that the polyimide resin (A) has radical polymerizable groups or cationic polymerizable groups on its molecular chain. A polyimide resin (A) having radical polymerizable groups or cationic polymerizable groups can be cured by the action of an initiator such as a radical polymerization initiator or a cationic polymerization initiator, and become insoluble in organic solvents. Therefore, when a photolithography method including regioselective exposure and development with a developer is applied to a film formation process using a polyimide varnish containing a polyimide resin (A) having radical polymerizable groups or cationic polymerizable groups, a patterned polyimide film can be formed.

[0036] The bonding positions of radical polymerizable groups or cationic polymerizable groups in the molecular chain of polyimide resin (A) are not particularly limited. Typical radical polymerizable groups include groups containing an ethylenically unsaturated double bond. Preferred ethylenically unsaturated double bond-containing groups include vinyl groups and alkenyl groups such as allyl groups, with (meth)acryloyl group-containing groups being more preferred. Typical cationic polymerizable groups include epoxy group-containing groups, oxetanyl group-containing groups, and vinyloxy group-containing groups. Among these, epoxy group-containing groups and vinyloxy group-containing groups are preferred. As for epoxy group-containing groups, alicyclic epoxy group-containing groups and glycidyl groups are preferred. An alicyclic epoxy group is an aliphatic cyclic group in which two adjacent carbon atoms constituting the ring are bonded via an oxygen atom. In other words, an alicyclic epoxy group has an epoxy group on an aliphatic ring that contains a three-membered ring consisting of two carbon atoms and one oxygen atom.

[0037] The amount of radical polymerizable groups or cationic polymerizable groups in the polyimide resin (A) is not particularly limited as long as it does not hinder the objectives of the present invention. The amount of radical polymerizable groups or cationic polymerizable groups in the polyimide resin (A) is 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, as moles of functional groups relative to the weight of the polyimide resin. The amount of radical polymerizable groups or cationic polymerizable groups in the polyimide resin (A) can typically be measured by NMR analysis.

[0038] The above-mentioned radical polymerizable group is preferably bonded to the aromatic ring in the molecular chain of the polyimide resin (A). A suitable example of a radical polymerizable group bonded to the aromatic ring in the molecular chain of the polyimide resin (A) is a group represented by the following formula (AI) or formula (A-II) that does not belong to a vinyloxy group-containing group. -( A 01 ) na-R 01 ...(AI) -( A 01 ) na -R 02 -A 02 -R 01 ...(A-II)

[0039] In equations (AI) and (A-II), R 01 R is an alkenyl group having 2 to 10 carbon atoms. 02 This is an alkylene group having 1 to 10 carbon atoms. A 01 These are -O-, -CO-, -CO-O-, -O-CO-, -CO-NH-, -NH-CO-, or -NH-. A 02 These are -O-, -CO-, -CO-O-, -O-CO-, -CO-NH-, -NH-CO-, or -NH-. na is either 0 or 1.

[0040] Suitable specific examples of radical polymerizable groups bonded to aromatic rings 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-O-R 03 , -NH-CH2CH2CH2-O-R 03 , -NH-CH2CH2CH2CH2-O-R 03 , -CO-NH-CH2CH2-O-R 03 , -CO-NH-CH2CH2CH2-O-R 03 , -CO-NH-CH2CH2CH2CH2-O-R 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 groups represented by are included. R in these groups 03 is an allyl group or a (meth)acryloyl group.

[0041] The cationically polymerizable group is preferably bonded to an aromatic ring in the molecular chain of the polyimide resin (A). Preferable examples of the cationically polymerizable group bonded to an aromatic ring in the molecular chain of the polyimide resin (A) include a vinyloxy group and groups represented by the following formulas (A3) to (A8). -(A 01 ) na -R 04 ···(A3) -(A 01 ) na -R02 -R 05 ...(A4) -( A 01 ) na -R 02 -(CO) nb -A 03 -R 04 ...(A5) -( A 01 ) na -R 02 -(CO) nb -A 03 -R 07 -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)

[0042] In equations (A3) to (A8), R 02 R is an alkylene group having 1 to 10 carbon atoms. 04 This is an epoxy alkyl 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 R is a vinyl group. 07 This is an alkylene group having 1 to 10 carbon atoms. A 01 These are -O-, -CO-, -CO-O-, -O-CO-, -CO-NH-, -NH-CO-, or -NH-. A 03 It is -O- or -NH-. nb is either 0 or 1.

[0043] Suitable specific examples of cationic polymerizable groups 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-R 07 , -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 The groups represented by these groups are shown. 07 This group is a vinyloxy group, a glycidyloxy group, an epoxycyclopentyl group, an epoxycyclohexyl group, or an epoxycycloheptyl group.

[0044] As described above, the polyimide resin (A) preferably has a radical polymerizable group or a cationic polymerizable group on the aromatic ring in the molecular chain. For this reason, the tetravalent organic group Y in formula (A1) 1 The base may be represented by the following formulas (A1-1) to (A1-3). [ka] In equations (A1-1) to (A1-3), R a01 , R a02 , and R a03 In the aforementioned equations (a1-1), (a1-2), and (a1-3), R a01 Ra 02 , and R a03 It is similar to that. In equations (A1-1), (A1-2), and (A1-3), Ra 06 These are radical polymerizable groups or cationic polymerizable groups. Examples of radical polymerizable groups and cationic polymerizable groups include the groups mentioned above, respectively. Tetracarboxylic dianhydrides themselves are highly reactive. For example, epoxy groups readily react with carboxylic acid anhydride groups. Therefore, Y 1 However, if the group is represented by formula (A1-1), formula (A1-2), or formula (A1-3), it is preferable to introduce a radical polymerizable group or a cationic polymerizable group onto the molecular chain of the polyamic acid or polyimide resin (A) after the polyamic acid or polyimide resin (A) has been synthesized.

[0045] Reactions for introducing radical polymerizable groups or cationic polymerizable groups include, for example, 1) An etherification reaction between a halogen atom bonded to an aromatic ring in the molecular chain of polyamic acid or polyimide resin (A) and an alcohol compound having a radical polymerizable group or a cationic polymerizable group. 2) Esterification reaction between a hydroxyl group bonded to an aromatic ring in the molecular chain of polyamic acid or polyimide resin (A) and a carboxylic acid halide having a radical polymerizable group or a cationic polymerizable group. 3) Esterification reaction between a carboxyl group bonded to an aromatic ring in the molecular chain of polyimide resin (A) and an organic halide having a radical polymerizable group or a cationic polymerizable group, and 4) Examples include N-substitution reactions between an amino group bonded to an aromatic ring in the molecular chain of a polyamic acid or polyimide resin (A) and an organic halide having a radical polymerizable group or a cationic polymerizable group. Reactions for introducing a radical polymerizable group or a cationic polymerizable group are not limited to these reactions.

[0046] Furthermore, after synthesizing a polyamic acid or polyimide resin (A) 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 the aromatic ring, deprotection can be performed by a well-known method to obtain a polyamic acid or polyimide resin (A) having a hydroxyl group, a carboxyl group, or an amino group on the aromatic ring.

[0047] The polyimide resin (A) preferably contains a structural unit represented by the following formula (A2) in its molecular chain. The structural unit represented by formula (A2) is X 5 The divalent organic group contains a divalent organic group having a radical polymerizable group or a cationic polymerizable group. [ka] (In formula (A2), Y 1 This is Y in equation (A1). 1 It is similar to X 5 (This refers to a divalent organic group having a radical polymerizable group or a cationic polymerizable group.)

[0048] X in equation (A2) 5 The divalent organic group as such is not particularly limited as long as it has a radical polymerizable group or a cationic polymerizable group, as long as it does not hinder the objectives of the present invention. 5 The divalent organic group may contain heteroatoms such as O, N, S, P, B, Si, and halogen atoms. The number of carbon atoms in the divalent organic group is preferably 1 to 50, and more preferably 1 to 20. The divalent organic group may be an aliphatic group, a group consisting of an aromatic group and an aliphatic group or a heteroatom, or an aromatic group. It is preferable that the divalent organic group is an aromatic group, or a group consisting of an aromatic group and an aliphatic group or a heteroatom. 5 In the divalent organic group, it is preferable that a radical polymerizable group or a cationic polymerizable group is bonded to the aromatic group.

[0049] The divalent organic group X in formula (A2)5 Preferably, this is a group in which a radical polymerizable group or a cationic polymerizable group is further bonded to the aromatic ring of an aromatic group represented by formulas (21) to (24) described later.

[0050] Organic group X having a radical polymerizable group or a cationic polymerizable group 5 The following are some suitable examples of this. [ka]

[0051] [ka]

[0052] [ka]

[0053] Furthermore, the polyimide resin (A) may contain a constituent unit represented by the following formula (A3) in its molecular chain. [ka] (In formula (A3), Y 1 This is Y in equation (A1). 1 It is similar to X 6 X is a divalent organic group that does not have a radical polymerizable group or a cationic polymerizable group. 6 This is a group that does not fall under the group represented by the following formula (A1-i). [ka] (In equation (A1-i), Y 1 , R a1 , R a2 n1 and n2 are the same as those in equation (A1).

[0054] X in equation (A3) 6It is typically a divalent organic residue derived from a diamine used as a raw material for polyamic acid, which is a precursor of polyimide resin (A). Examples of diamines that yield the divalent organic residue include compounds represented by the following formula (a3-1). Compounds represented by the following formula (a3-1) can typically be used. Diamine compounds may be used individually or in combination of two or more. H2N-A 2 -NH2···(a3-1) (In formula (a3-1), A 2 represents a divalent organic group. However, A 2 The divalent organic group does not contain the substructure represented by formula (a1).

[0055] In formula (a3-1), A 2 This is a divalent organic group, and in addition to the two amino groups in formula (a3-1), it may have one or more substituents. Preferred examples of substituents include fluorine atoms, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, fluorinated alkyl groups having 1 to 6 carbon atoms, fluorinated alkoxy groups having 1 to 6 carbon atoms, or hydroxyl groups. When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferable that it be a perfluoroalkyl group or a perfluoroalkoxy group.

[0056] 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 This may be an aliphatic group, but it is preferably an organic group containing one or more aromatic rings.

[0057] A 2If the organic group contains one or more aromatic rings, the organic group may be one aromatic group itself, or it may be a group in which two or more aromatic groups are bonded via bonds containing aliphatic hydrocarbon groups and halogenated aliphatic hydrocarbon groups, or heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 2 Examples of heteroatom-containing bonds, such as oxygen atoms, sulfur atoms, and nitrogen atoms, include -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO2-, -S-, and -SS-, with -O-, -CO-, -SO-, -SO2-, -S-, and -SS- being preferred.

[0058] A 2 The aromatic ring bonded to the amino group inside is preferably a benzene ring. 2 If the ring bonded to the amino group is a condensed ring containing two or more rings, it is preferable that the ring bonded to the amino group in the condensed ring is a benzene ring. Also, A 2 The aromatic ring contained therein may be an aromatic heterocycle.

[0059] A 2 If the organic group contains an aromatic ring, it is preferable that the organic group is at least one of the groups represented by the following formulas (21) to (24) from the viewpoint of the heat resistance of the cured product formed using the resin composition. [ka] (In formulas (21) to (24), R 111Q represents one selected from the group consisting of a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, and a halogenated alkyl group having 1 to 4 carbon atoms. In formula (24), Q is a 9,9'-fluorenylidene group, or formula: -C6H4-, -CONH-C6H4-NHCO-, -NHCO-C6H4-CONH-, -O-C6H4-CO-C6H4-O-, -OCO-C6H4-COO-, -OCO-C6H4-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 This indicates one selected from the group consisting of H6-O- and -O-C6H4-O- groups. In the example of Q, -C6H4- is a phenylene group, and m-phenylene groups and p-phenylene groups are preferred, with p-phenylene groups being more preferred. Also, -C 10 H6- is a naphthalene diyl group, preferably naphthalene-1,2-diyl, naphthalene-1,4-diyl, naphthalene-2,3-diyl, naphthalene-2,6-diyl, and naphthalene-2,7-diyl, and more preferably naphthalene-1,4-diyl and naphthalene-2,6-diyl.

[0060] R in equations (21) to (24) 111 From the viewpoint of the heat resistance of the formed polyimide resin (A), hydrogen atoms, hydroxyl groups, fluorine atoms, methyl groups, ethyl groups, or trifluoromethyl groups are more preferred, and hydrogen atoms, hydroxyl groups, or trifluoromethyl groups are particularly preferred.

[0061] In formula (24), Q is preferably a 9,9'-fluorenylidene group, -O-C6H4-O-, -C(CF3)2-, -O-, -C(CH3)2-, -CH2-, or -CONH-, from the viewpoint of the heat resistance of the formed polyimide resin (A).

[0062] When using an aromatic diamine as the diamine compound represented by formula (a3-1), for example, the aromatic diamines shown below can be suitably used. In other words, aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 4,4'-diaminobenz Examples include anilides, 3,3'-diaminobenzanilide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 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 due to their price, availability, etc.

[0063] Also, A 2 As such, silicon atom-containing groups that may have a chain-like aliphatic group and / or an aromatic ring can be employed. Typical silicon atom-containing groups that can be used are those shown below. [ka]

[0064] Furthermore, from the viewpoint of further improving the mechanical properties of the resulting polyimide resin (A), 2In addition, a group represented by the following formula (Si-1) can also be preferably used. [ka] (In formula (Si-1), R 112 and R 113 Each of these is independently a single bond or a methylene group, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 114 , R 115 , R 116 , and R 117 Each of these independently includes an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an amino group having 20 carbon atoms, and -OR 118 The group represented by (R 118 (where l is an integer between 3 and 50.)

[0065] R in equation (Si-1) 112 and R 113 In this context, 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 include dimethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, etc.

[0066] R in equation (Si-1) 112 and R 113 In this context, 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 include cyclobutylene group, cyclopentylene group, cyclohexylene group, cycloheptylene group, etc. R in equation (Si-1) 112 and R 113In this context, 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, such as a phenylene group or a naphthylene group.

[0067] R in equation (Si-1) 114 , R 115 , R 116 , and R 117 As for the alkyl group having 1 to 20 carbon atoms, alkyl groups having 1 to 10 carbon atoms are preferred from the viewpoint of heat resistance and residual stress, and specifically include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, etc. R in equation (Si-1) 114 , R 115 , R 116 , and R 117 In this context, cycloalkyl groups having 3 to 20 carbon atoms are preferred from the viewpoint of heat resistance and residual stress, and specific examples include cyclopentyl groups and cyclohexyl groups. R in equation (Si-1) 114 , R 115 , R 116 , and R 117 In this context, the aryl group having 6 to 20 carbon atoms is preferred from the viewpoint of heat resistance and residual stress, and specific examples include the phenyl group, tolyl group, naphthyl group, etc. R in equation (Si-1) 114 , R 115 , R 116 , and R 117 Examples of amino groups containing 20 or fewer carbon atoms include amino groups and substituted amino groups (e.g., bis(trialkylsilyl)amino groups). R in equation (Si-1) 114 , R 115 , R 116 , and R 117 -OR in 118Examples of groups represented by include methoxy, ethoxy, propoxy, isopropyloxy, butoxy, phenoxy, tolyloxy, naphthyloxy, propenyloxy (e.g., allyloxy), and cyclohexyloxy groups. Among them, R 114 , R 115 , R 116 , and R 117 Preferably, these are methyl groups, ethyl groups, propyl groups, and phenyl groups.

[0068] 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 with amino groups at both ends (e.g., X-22-1660B-3 (number average molecular weight approximately 4,400) and X-22-9409 (number average molecular weight approximately 1,300) from Shin-Etsu Chemical Co., Ltd.), and dimethyl silicones with amino groups at both ends (e.g., X-22-161A (number average molecular weight approximately 1,600), X-22-161B (number average molecular weight approximately 3,000), and KF8012 (number average molecular weight approximately 4,400) from Shin-Etsu Chemical Co., Ltd.; BY16-835U from Toray Dow Corning (number average molecular weight approximately 900); and Cyraplane FM3311 from JNC Corporation (number average molecular weight approximately 1,000)).

[0069] The method for producing the polyimide resin (A) described above is not particularly limited. Typically, the polyimide resin (A) described above can be produced by reacting a polyamic acid having a structure corresponding to the structure of the above-mentioned constituent units with a tetracarboxylic dianhydride to obtain a polyamic acid, and then imidizing the polyamic acid. When producing polyamic acid, tetracarboxylic dianhydride and diamine may be used individually or in combination of two or more types. As described above, the polyimide resin (A) may have radical polymerizable groups or cationic polymerizable groups. The radical polymerizable groups or cationic polymerizable groups may be introduced onto the molecular chain after the synthesis of the polyamic acid or after the synthesis of the polyimide resin (A). When introducing radical polymerizable groups or cationic polymerizable groups onto the molecular chains of polyamic acid or polyimide resin (A) after the synthesis of polyamic acid or polyimide resin (A), the method of introduction is not particularly limited. Since carboxyl groups and amide bonds are prone to undesirable side reactions with radical polymerizable groups or cationic polymerizable groups, it is preferable to introduce radical polymerizable groups or cationic polymerizable groups into polyimide resin (A) rather than into polyamic acid. Typical examples of methods for introducing radical polymerizable groups or cationic polymerizable groups onto molecular chains include reacting a polyamic acid or polyimide resin (A) having functional groups such as hydroxyl groups, amino groups, or carboxyl groups with a carboxylic acid having a radical polymerizable group, a carboxylic acid halide having a radical polymerizable group, an alcohol having a radical polymerizable group, a phenol having a radical polymerizable group, an amine having a radical polymerizable group, a halogenated compound having a radical polymerizable group, a carboxylic acid having a cationic polymerizable group, a carboxylic acid halide having a cationic polymerizable group, an alcohol having a cationic polymerizable group, a phenol having a cationic polymerizable group, an amine having a cationic polymerizable group, or a halogenated compound having a cationic polymerizable group by known methods such as a condensation reaction using a well-known condensing agent or Williamson's etherification reaction.

[0070] The amounts of tetracarboxylic dianhydride and diamine compound used when synthesizing polyamic acid are not particularly limited, but it is preferable to use 0.50 moles to 1.50 moles of diamine compound per mole of tetracarboxylic dianhydride, more preferably 0.60 moles to 1.30 moles, and particularly preferably 0.70 moles to 1.20 moles. Furthermore, the weight-average molecular weight of the resulting polyamic acid can be appropriately set according to its intended use. The weight-average molecular weight of the polyamic acid is, for example, 5000 or more, preferably 7500 or more, and more preferably 10000 or more. On the other hand, the weight-average molecular weight of the resulting polyamic acid is, for example, 100000 or less, preferably 80000 or less, and more preferably 75000 or less. This weight-average molecular weight can be obtained by adjusting the proportions of tetracarboxylic dianhydride and diamine compound, as well as reaction conditions such as the solvent and reaction temperature, to arrive at the value mentioned above.

[0071] The reaction between tetracarboxylic dianhydride and diamine compounds is usually carried out in an organic solvent. The organic solvent used in the reaction between tetracarboxylic dianhydride and diamine compounds is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride and the diamine compound and does not react with them. The organic solvent can be used alone or in a mixture of two or more.

[0072] Examples of organic solvents used in the reaction between tetracarboxylic dianhydrides and diamine compounds 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.

[0073] 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 due to their solubility of the resulting polyamic acid and polyimide resin (A).

[0074] The temperature at which the tetracarboxylic dianhydride reacts with the diamine compound is not particularly limited, as long as the reaction proceeds well. Typically, the reaction temperature between the tetracarboxylic dianhydride and the diamine compound is preferably -5°C to 150°C, more preferably 0°C to 120°C, and particularly preferably 0°C to 70°C. The reaction time between the tetracarboxylic dianhydride and the diamine compound varies depending on the reaction temperature, but is typically preferably 1 hour to 50 hours, more preferably 2 hours to 40 hours, and particularly preferably 5 hours to 30 hours.

[0075] A solution containing polyamic acid can be obtained by the method described above. The obtained polyamic acid is ring-closed and imidized to produce polyimide resin (A). The method of imidation is not particularly limited. Imidation may be carried out by heating or by using an imidating agent.

[0076] When imidization is performed by heating, the heating may be carried out in a solution or suspension of polyamic acid, or in solid polyamic acid. Since the above polyimide resin (A) exhibits excellent solubility in organic solvents, it is preferable to carry out the heating for imidization in a solution of polyamic acid. When performing imidization by heating a polyamic acid solution, it is preferable to remove the water produced as a by-product during imidization while heating. The heating conditions for imidization are not particularly limited, as long as the polyamic acid or polyimide resin (A) does not decompose and the imidization proceeds well. When heating a polyamic acid solution, the heating temperature is typically preferably 150°C to 280°C, more preferably 160°C to 250°C, and particularly preferably 170°C to 230°C. When heating a solid polyamic acid, the heating temperature is typically preferably 180°C to 400°C, and more preferably 200°C to 350°C. The heating time depends on the heating temperature, but is typically preferably between 1 hour and 24 hours, and more preferably between 2 hours and 12 hours.

[0077] When imidizing polyamic acids with an imidating agent, the imidating agent is usually added to a solution or suspension of the polyamic acid to carry out the imidating. For example, the same organic solvents used in the preparation of polyamic acids can be used as the organic solvent for imidating with an imidating agent. When imidation is performed using an imidizing agent, the concentration of polyamic acid in the solution or suspension of polyamic acid is not particularly limited. Typically, the concentration of polyamic acid in the solution or suspension of polyamic acid 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 imidizing agent used is not particularly limited. The amount of imidizing agent used is selected according to the type of imidizing agent so that the polyamic acid is imidized to the desired extent. The reaction temperature when imidation is carried out with an imidizing agent is not particularly limited. The reaction temperature is preferably, for example, 0°C to 100°C, and more preferably 5°C to 50°C. The duration of the imidation reaction when using an imidizing agent is not particularly limited. Depending on the type of imidizing agent, the imidation reaction is preferably carried out for, for example, 30 minutes to 24 hours, more preferably for 1 hour to 12 hours, and even more preferably for 2 hours to 6 hours or more.

[0078] Examples of imidizing agents include acetic anhydride, propionic anhydride, benzoic anhydride, trifluoroacetic anhydride, acetyl chloride, tosyl chloride, mesyl chloride, ethyl chlorformate, triphenylphosphine and dibenzimidazolyl disulfide, dicyclohexylcarbodiimide, carbodiimidazole, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, and N,N'-disuccinimidyl oxalate as dehydrating agents, as well as 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.

[0079] The ratio of the mass of polyimide resin (A) to the mass of polyimide varnish is determined appropriately, taking into account the viscosity of the polyimide varnish, as well as the application method and the thickness of the applied film. Typically, the ratio of the mass of polyimide resin (A) to the mass of polyimide varnish is 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.

[0080] <Monomer compound (B)> If the polyimide resin (A) has radical polymerizable groups, the polyimide varnish may contain, together with the polyimide resin (A), a monomer compound (B) having an ethylenically unsaturated double bond. Such a monomer compound may be a monofunctional monomer compound or a polyfunctional monomer compound, with polyfunctional monomer compounds being preferred.

[0081] Examples of monofunctional monomer compounds 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-acrylamide-2-methylpropanesulfonic acid, tert-butylacrylamidesulfonic acid, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, Examples 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 individually or in combination of two or more.

[0082] 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, dimethylol tricyclodecane 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, and 2,2-bis(4-(meth)acryloxydiethoxypheny Examples include polyfunctional monomer compounds such as (I)propane, 2,2-bis(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, diglycidyl phthalate di(meth)acrylate, glycerin triacrylate, glycerin polyglycidyl ether poly(meth)acrylate, urethane (meth)acrylate (i.e., tolylene diisocyanate), reaction products of trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and 2-hydroxyethyl (meth)acrylate, methylenebis(meth)acrylamide, (meth)acrylamide methylene ether, condensates of polyhydric alcohols and N-methylol(meth)acrylamide, and triacrylic formal. These polyfunctional monomer compounds can be used individually or in combination of two or more.

[0083] Among these monomer compounds having ethylenically unsaturated double bonds, polyfunctional monomer compounds with three or more functions are preferred, polyfunctional monomer compounds with four or more functions are more preferred, and polyfunctional monomer compounds with five or more functions 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.

[0084] If the polyimide resin (A) has a vinyloxy group-containing group as a cationic polymerizable group, the polyimide varnish may contain a vinyl ether compound as a monomer compound (B) together with the polyimide resin (A). Such a vinyl ether compound may be a monofunctional compound or a polyfunctional compound.

[0085] Suitable specific examples of vinyl ether compounds include vinylphenyl 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-Divinyl Examples include roxynaphthalene, 1,2-divinyloxyfluorene, 3,4-divinyloxyfluorene, 2,7-divinyloxyfluorene, 4,4'-divinyloxybiphenyl, 3,3'-divinyloxybiphenyl, 2,2'-divinyloxybiphenyl, 3,4'-divinyloxybiphenyl, 2,3'-divinyloxybiphenyl, 2,4'-divinyloxybiphenyl, and aromatic divinyl ether compounds such as bisphenol A divinyl ether. These vinyl ether compounds may be used in combination of two or more types.

[0086] If the polyimide resin (A) has an epoxy group-containing group as a cationic polymerizable group, the polyimide varnish 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; cyclic aliphatic epoxy resins such as epoxidized dicyclopentadiene type phenol resins; aromatic epoxy resins such as epoxidized naphthalene type phenol resins; glycidyl ester type epoxy resins such as dimer acid glycidyl esters and triglycidyl esters; glycidylamine type epoxy resins such as tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, tetraglycidylmetaxylylenediamine, and tetraglycidylbisaminomethylcyclohexane; triglyc Heterocyclic epoxy resins such as cidylicisocyanurates; phloroglycinol 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 tetrahydroxyphenylethanetetraglycidyl ether, tetraglycidylbenzophenone, bisresorcinol tetraglycidyl ether, and tetraglycidoxybiphenyl; and 1,2-epoxy-4-(2-oxyranyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol.The 1,2-epoxy-4-(2-oxyranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol is commercially available as EHPE-3150 (manufactured by Daicel Corporation).

[0087] Furthermore, oligomer or polymer-type polyfunctional epoxy compounds can also be preferably used. Typical examples of oligomeric 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, epoxidized naphthalene type phenol resins, and the like.

[0088] Other suitable examples of epoxy compounds include polyfunctional alicyclic epoxy compounds having alicyclic epoxy groups.

[0089] Specific examples of alicyclic epoxy compounds include 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meth-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'-epoxy Examples include epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), ethylene glycol di(3,4-epoxycyclohexylmethyl) ether, ethylenebis(3,4-epoxycyclohexanecarboxylate), 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).

[0090] Among these specific examples of alicyclic epoxy compounds, alicyclic epoxy compounds represented by the following formulas (b01-1) to (b01-5) are preferred because they yield cured products with high hardness.

[0091] [ka] (In formula (b01-1), Z 01 R indicates a single bond or a linking group (a divalent group having one or more atoms). b01 ~R b018 Each of these groups is independently selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups.

[0092] Linking group Z 01Examples include divalent hydrocarbon groups, -O-, -O-CO-, -S-, -SO-, -SO2-, -CBr2-, -C(CBr3)2-, -C(CF3)2-, and -R b019 Examples include divalent groups selected from the group consisting of -O-CO- and groups formed by the bonding of multiple such groups.

[0093] Linking group Z 01 Examples of divalent hydrocarbon groups include linear or branched alkylene groups with 1 to 18 carbon atoms, and divalent alicyclic hydrocarbon groups. Examples of linear or branched alkylene groups with 1 to 18 carbon atoms include methylene groups, methylmethylene groups, dimethylmethylene groups, dimethylmethylene groups, trimethylene groups, and so on. Examples of the above-mentioned divalent alicyclic hydrocarbon groups include cycloalkylene groups (including cycloalkylidene groups) such as 1,2-cyclopentylene groups, 1,3-cyclopentylene groups, cyclopentylidene groups, 1,2-cyclohexylene groups, 1,3-cyclohexylene groups, 1,4-cyclohexylene groups, and cyclohexylidene groups.

[0094] R b019 This is an alkylene group having 1 to 8 carbon atoms, and is preferably a methylene group or an ethylene group.

[0095] [ka] (In formula (b01-2), R b01 ~R b018 R is a group selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups. b02 and R b010 These may be joined together. b013 and R b016 They may be joined to each other to form a ring. a1 (This is either 0 or 1.)

[0096] As an alicyclic epoxy compound represented by the above formula (b01-2), the m in the above formula (b01-2) is a1Compounds that correspond to compounds where is 0, and are represented by the following formula (b01-2-1), are preferred. [ka] (In formula (b01-2-1), R b01 ~R b012 R is a group selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups. b02 and R b010 They may be joined to each other to form a ring.

[0097] [ka] (In formula (b01-3), R b01 ~R b010 R is a group selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups. b02 and R b08 They may be joined together.

[0098] [ka] (In formula (b01-4), R b01 ~R b012 R is a group selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups. b02 and R b010 They may be joined together.

[0099] [ka] (In formula (b01-5), R b01 ~R b012 (This group is selected from the group consisting of hydrogen atoms, halogen atoms, and organic groups.)

[0100] In formulas (b01-1) to (b01-5), R b01 ~R b018If the group is an organic group, the organic group is not particularly limited as long as it does not hinder the objectives of the present invention, and may be a hydrocarbon group, a group consisting of a carbon atom and a halogen atom, or a group that includes a halogen atom, an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, and other heteroatoms along with the carbon atom and hydrogen atom. Examples of halogen atoms include chlorine atoms, bromine atoms, iodine atoms, and fluorine atoms.

[0101] Preferred organic groups include hydrocarbon groups, groups consisting of carbon atoms, hydrogen atoms, and oxygen atoms, halogenated hydrocarbon groups, groups consisting of carbon atoms, oxygen atoms, and halogen atoms, and groups consisting of carbon atoms, hydrogen atoms, oxygen atoms, and halogen atoms. When the organic group is a hydrocarbon group, it may be an aromatic hydrocarbon group, an aliphatic hydrocarbon group, or a group containing both an aromatic 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.

[0102] Specific examples of hydrocarbon groups 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 groups. Examples include linear alkenyl groups such as 2-n-butenyl and 3-n-butenyl groups; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl groups; 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 groups; and aralkyl groups such as benzyl, phenethyl, α-naphthylmethyl, β-naphthylmethyl, α-naphthylethyl, and β-naphthylethyl groups.

[0103] Specific examples of halogenated hydrocarbon groups include halogenated chain alkyl groups such as chloromethyl group, dichloromethyl group, trichloromethyl group, bromomethyl group, dibromomethyl group, tribromomethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, heptafluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group, perfluorooctyl group, perfluorononyl group, and perfluorodecyl group; halogenated cycloalkyl groups such as 2-chlorocyclohexyl group, 3-chlorocyclohexyl group, 4-chlorocyclohexyl group, 2,4-dichlorocyclohexyl group, 2-bromocyclohexyl group, 3-bromocyclohexyl group, and 4-bromocyclohexyl group; halogenated aryl groups such as 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 2,6-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 2-bromophenyl group, 3-bromophenyl group, 4-bromophenyl group, 2-fluorophenyl group, 3-fluorophenyl group, and 4-fluorophenyl group; and halogenated aralkyl groups such as 2-chlorophenylmethyl group, 3-chlorophenylmethyl group, 4-chlorophenylmethyl group, 2-bromophenylmethyl group, 3-bromophenylmethyl group, 4-bromophenylmethyl group, 2-fluorophenylmethyl group, 3-fluorophenylmethyl group, and 4-fluorophenylmethyl group.

[0104] Specific examples of groups consisting of carbon atoms, hydrogen atoms, and oxygen atoms include hydroxy-chain alkyl groups such as hydroxymethyl group, 2-hydroxyethyl group, 3-hydroxy-n-propyl group, and 4-hydroxy-n-butyl group; halogenated cycloalkyl groups such as 2-hydroxycyclohexyl group, 3-hydroxycyclohexyl group, and 4-hydroxycyclohexyl group; 2-hydroxyphenyl group, 3-hydroxyphenyl group, 4-hydroxyphenyl group, 2,3-dihydroxyphenyl group, 2,4-dihydroxyphenyl group, and 2,5-dihydroxyphenyl group. Hydroxyaryl groups such as phenyl group, 2,6-dihydroxyphenyl group, 3,4-dihydroxyphenyl group, and 3,5-dihydroxyphenyl group; hydroxyaralkyl groups such as 2-hydroxyphenylmethyl group, 3-hydroxyphenylmethyl group, and 4-hydroxyphenylmethyl group; methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butyloxy group, isobutyloxy group, sec-butyloxy group, tert-butyloxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group Chain-like alkoxy groups such as ruoxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-tridecyloxy group, n-tetradecyloxy group, n-pentadecyloxy group, n-hexadecyloxy group, n-heptadecyloxy group, n-octadecyloxy group, n-nonadecyloxy group, and n-icosyloxy group; vinyloxy group, 1-propenyloxy group, 2-n-propenyloxy group (allyloxy group), 1-n-butenyloxy group, 2-n-butenyloxy group, and 3-n-butenyl Chain-like alkenyloxy groups such as oxy groups; aryloxy groups such as phenoxy group, o-tolyloxy group, m-tolyloxy group, p-tolyloxy group, α-naphthyloxy group, β-naphthyloxy group, biphenyl-4-yloxy group, biphenyl-3-yloxy group, biphenyl-2-yloxy group, anthryloxy group, and phenanthryloxy group; aralkyloxy groups such as benzyloxy group, phenethyloxy group, α-naphthylmethyloxy group, β-naphthylmethyloxy group, α-naphthylethyloxy group, and β-naphthylethyloxy group;Alkoxyalkyl groups such as methoxymethyl group, ethoxymethyl group, n-propoxymethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-n-propoxyethyl group, 3-methoxy-n-propyl group, 3-ethoxy-n-propyl group, 3-n-propoxy-n-propyl group, 4-methoxy-n-butyl group, 4-ethoxy-n-butyl group, and 4-n-propoxy-n-butyl group; methoxymethoxy group, ethoxymethoxy group, n-propoxymethoxy group, 2-methoxyethoxy group, 2-ethoxyethoxy group, 2-n-propoxyethoxy group Alkoxyalkoxy groups such as 3-methoxy-n-propoxy group, 3-ethoxy-n-propoxy group, 3-n-propoxy-n-propoxy group, 4-methoxy-n-butyloxy group, 4-ethoxy-n-butyloxy group, and 4-n-propoxy-n-butyloxy group; Alkoxyaryl groups such as 2-methoxyphenyl group, 3-methoxyphenyl group, and 4-methoxyphenyl group; Alkoxyaryloxy groups such as 2-methoxyphenoxy group, 3-methoxyphenoxy group, and 4-methoxyphenoxy group; Formyl group, acetyl group, propionyl Aliphatic acyl groups such as benzoyl group, butanoyl group, pentanoyl group, hexanoyl group, heptanyl group, octanoyl group, nonanoyl group, and decanoyl group; aromatic acyl groups such as benzoyl group, α-naphthoyl group, and β-naphthoyl group; methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, n-butyloxycarbonyl group, n-pentyloxycarbonyl group, n-hexylcarbonyl group, n-heptyloxycarbonyl group, n-octyloxycarbonyl group, n-nonyloxycarbonyl group, and n-decyloxycarbonyl group These include linear alkyloxycarbonyl groups such as the yl group; aryloxycarbonyl groups such as the phenoxycarbonyl group, α-naphthoxycarbonyl group, and β-naphthoxycarbonyl group; aliphatic acyloxy groups such as the formyloxy group, acetyloxy group, propionyloxy group, butanoyloxy group, pentanoyloxy group, hexanoyloxy group, heptanoyloxy group, octanoyloxy group, nonanoyloxy group, and decanoyloxy group; and aromatic acyloxy groups such as the benzoyloxy group, α-naphthoyloxy group, and β-naphthoyloxy group.

[0105] 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, since it is easy to form a cured film excellent in mechanical properties, R b01 ~R b018 is more preferably all hydrogen atoms.

[0106] In formulas (b01-2) to (b01-5), R b01 ~R b018 are the same as R b01 ~R b018 in formula (b01-1). In formula (b01-2) and formula (b01-4), when R b02 and R b010 are bonded to each other, in formula (b01-2), when R b013 and R b016 are bonded to each other, and in formula (b01-3), when R b02 and R b08 are bonded to each other, examples of the divalent group formed include -CH2- and -C(CH3)2-.

[0107] 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), and 2,2-bis(3,4-epoxycyclohexan-1-yl)propane [=2,2-bis(3,4-epoxycyclohexyl)propane].

Chemical formula

[0108] Among the alicyclic epoxy compounds represented by formula (b01-2), specific examples of suitable compounds include alicyclic epoxy compounds represented by the following formula (b01-2a) and the following formula (b01-2b).

Chemical formula

[0109] Among the alicyclic epoxy compounds represented by formula (b01-3), a specific example of a suitable compound is S-spiro[3-oxatricyclo[3.2.1.0 2,4 Examples include octane-6,2'-oxirane.

[0110] Specific examples of suitable alicyclic epoxy compounds represented by formula (b01-4) include 4-vinylcyclohexene dioxide, dipentene dioxide, limonene dioxide, and 1-methyl-4-(3-methyloxiran-2-yl)-7-oxabicyclo[4.1.0]heptane.

[0111] Among the alicyclic epoxy compounds represented by formula (b01-5), suitable specific examples include 1,2,5,6-diepoxycyclooctane.

[0112] Furthermore, compounds represented by the following formula (b1-I) can be suitably used as epoxy compounds. [ka] (In formula (b1-I), X b1 , X b2 , and X b3 Each of these is an organic group that may independently contain a hydrogen atom or an epoxy group, and X b1 , X b2 , and X b3 The total number of epoxy groups it possesses is two or more.

[0113] As the compound represented by the above formula (b1-I), the compound represented by the following formula (b1-II) is preferred. [ka] (In formula (b1-II), R b20 ~R b22These are linear, branched, or cyclic alkylene groups, arylene groups, -O-, -C(=O)-, -NH-, and combinations thereof, and may be the same or different. 1 ~E 3 is at least one substituent or hydrogen atom selected from the group consisting of epoxy groups, oxetanyl groups, ethylenically unsaturated groups, alkoxysilyl groups, isocyanate groups, blocked isocyanate groups, thiol groups, carboxyl groups, hydroxyl groups, and succinic anhydride groups. However, E 1 , E 2 , and E 3 The total number of epoxy groups it possesses is two or more.

[0114] In formula (b1-II), R b20 and E 1 , R b21 and E 2 , and R b22 and E 3 The groups represented by are preferably, for example, at least two of which are groups represented by the following formula (b1-IIa), and more preferably, all of them are groups represented by the following formula (b1-IIa). It is preferable that multiple groups represented by formula (b1-IIa) attached to a single compound are the same group. -LC a (b1-IIa) (In formula (b1-IIa), L is a linear, branched, or cyclic alkylene group, an arylene group, -O-, -C(=O)-, -NH-, and a group consisting of combinations thereof, C a is an oxyranyl group (epoxy group). In formula (b1-IIa), L and C a (They may be joined together to form a ring structure.)

[0115] In formula (b1-IIa), as the linear, branched or cyclic alkylene group for L, an alkylene group having 1 to 10 carbon atoms is preferable, and as the arylene group for L, an arylene group having 5 to 10 carbon atoms is preferable. In formula (b1-IIa), L is preferably a group consisting of a linear alkylene group having 1 to 3 carbon atoms, a phenylene group, -O-, -C(=O)-, -NH- and a combination thereof, and at least one of a linear alkylene group having 1 to 3 carbon atoms such as a methylene group and a phenylene group, or a group consisting of a combination of any of the foregoing and at least one of -O-, -C(=O)- and -NH- is preferable.

[0116] In formula (b1-IIa), when L and C a are bonded to form a cyclic structure, for example, when a branched alkylene group and an epoxy group are bonded to form a cyclic structure (a structure having an epoxy group of an alicyclic structure), examples include organic groups represented by the following formulas (b1-IIb) to (b1-IId).

Chemical Formula

[0117] Hereinafter, examples of epoxy compounds having an oxiranyl group or an alicyclic epoxy group will be shown as examples of the compound represented by formula (b1-II), but the compound is not limited to these.

Chemical Formula

[0118]

Chemical Formula

[0119] Further, a siloxane compound having two or more glycidyl groups in the molecule (hereinafter sometimes simply referred to as "siloxane compound") can be suitably used as the epoxy compound.

[0120] Siloxane compounds are compounds that have a siloxane skeleton composed of siloxane bonds (Si-O-Si) and two or more glycidyl groups within their molecule.

[0121] Examples of siloxane skeletons in siloxane compounds include cyclic siloxane skeletons and cage-type and ladder-type polysilsesquioxane skeletons.

[0122] Among 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]

[0123] In formula (b1-III), R b24 , and R b25 This represents a monovalent group or alkyl group containing an epoxy group. However, in the compound represented by formula (b1-III), x1 R b24 and x1 R b25 Of these, at least two are monovalent groups containing epoxy groups. Also, x1 in formula (b1-III) represents an integer of 3 or greater. Note that R in the compound represented by formula (b1-III) b24 , R b25 They may be the same or they may be different. Also, multiple R b24 They may be the same or they may be different. Multiple R b25 They may be the same or they may be different. Examples of the alkyl groups mentioned above include linear or branched alkyl groups having 1 to 18 carbon atoms (preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms), such as methyl, ethyl, propyl, and isopropyl groups.

[0124] In formula (b1-III), x1 represents an integer of 3 or more, and among these, an integer between 3 and 6 is preferred in that it exhibits excellent crosslinking reactivity when forming a cured film. The siloxane compound has two or more epoxy groups in its molecule, preferably two to six, and particularly preferably two to four, from the viewpoint of excellent crosslinking reactivity when forming a cured film.

[0125] The monovalent groups containing the above epoxy group include alicyclic epoxy groups and -D A -OR b26 A glycidyl ether group represented by [D A R indicates an alkylene group, b26 [where 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. Above D A Examples of (alkylene groups) include linear or branched alkylene groups having 1 to 18 carbon atoms, such as methylene groups, methylmethylene groups, dimethylmethylene groups, dimethylmethylene groups, dimethylene groups, and trimethylene groups. [ka] (In the above formulas (b1-IIIa) and (b1-IIIb), D 1 and D 2 Each of these independently represents an alkylene group, and ms represents an integer between 0 and 2 (inclusive).

[0126] In addition to the siloxane compound represented by formula (b1-III), the polyimide varnish may also contain compounds having a siloxane skeleton, such as alicyclic epoxy group-containing cyclic siloxanes, alicyclic epoxy group-containing silicone resins described in Japanese Patent Publication No. 2008-248169, and organopolysilsesquioxane resins having at least two epoxy functional groups in one molecule, as described in Japanese Patent Publication No. 2008-19422.

[0127] More specifically, examples of siloxane compounds include cyclic siloxanes having two or more glycidyl groups in the molecule, as represented by the following formula. Alternatively, commercially available siloxane compounds 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.) can be used.

[0128] [ka]

[0129] [ka]

[0130] The content of monomer compound (B) in the polyimide varnish is not particularly limited as long as it does not hinder the objectives of the present invention. The content of monomer compound (B) in the polyimide varnish is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 0.5 parts by mass or more and 40 parts by mass or less, and particularly preferably 1 part by mass or more and 25 parts by mass or less, when the mass of the polyimide varnish excluding the mass of solvent (S) described later is 100 parts by mass.

[0131] <Photoinitiator (C)> The polyimide varnish preferably contains a photoinitiator (C). If the polyimide resin (A) has radical polymerizable groups, a photoradical polymerization initiator (C1) may be used as the photoinitiator (C). If the polyimide resin (A) has cationic polymerizable groups, a photocationic polymerization initiator (C2) may be used as the photoinitiator (C). The photoinitiator (C) is not particularly limited, and conventionally known photopolymerization initiators can be used.

[0132] Specifically, the photoradical polymerization initiator (C1) is 1-hydroxycyclohexylphenyl 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-diphenylethane-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-carbazole-3-yl]ethanone oxime, (9-ethyl-6-nitro-9H-carbazole-3-yl)[4-(2-methoxy-1-methylethoxy)-2-methylphenyl]methanone O-acetyloxime, 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, benzyldimethyl Ketal, 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, o-methyl 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-methoxy Benzophenone, benzyl, 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 n, p-tert-butyldichloroacetophenone, α,α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosverone, pentyl-4-dimethylaminobenzoate, 9-phenylacridin, 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 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 individually or in combination of two or more.

[0133] Typical photocationic polymerization initiators (C2) include onium salts. Examples of photocationic polymerization initiators (C2) include 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.

[0134] The content of the photoinitiator (C) in the polyimide varnish is not particularly limited as long as the polyimide varnish has the desired photolithography properties. Typically, the content of the photoinitiator (C) in the polyimide varnish is 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, based on 100 parts by mass of the total mass of the polyimide resin (A) and the monomer compound (B).

[0135] Polyimide varnish contains an organic solvent (S). The type of organic solvent (S) is not particularly limited as long as it does not dissolve the polyimide resin (A) or other components well. From the standpoint of good solubility of the polyimide resin (A), it is preferable that the organic solvent (S) 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 preferred 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.

[0136] <Other ingredients> Polyimide varnish may contain various additives other than those described above, as needed. Examples of additives include colorants, dispersants, sensitizers, adhesion promoters, antioxidants, UV absorbers, anti-fouling agents, defoamers, and surfactants. Furthermore, polyimide varnish may contain various fillers or reinforcing materials, as needed. The amount of various additives used is not particularly limited as long as it does not hinder the objective of the present invention. It can be appropriately adjusted within a range of, for example, 0.001% by mass or more and 60% by mass or less relative to the mass of the solid content of the polyimide varnish, and preferably 0.05% by mass or more and 5% by mass or less. The amount of filler or reinforcing material used is not particularly limited as long as it does not hinder the objective of the present invention. Typically, the amount of filler or reinforcing material used is preferably 1% to 300% by mass, more preferably 5% to 200% by mass, and even more preferably 10% to 100% by mass, relative to the mass of polyamic acid (A).

[0137] ≪Method for producing polyimide films≫ After applying the polyimide varnish described above onto a desired substrate to form a coating film, a polyimide film is formed by removing at least a portion of the organic solvent (S) from the coating film. In other words, the coating process involves applying the aforementioned polyimide varnish onto the substrate to form a coating film, An organic solvent removal step, which removes at least a portion of the organic solvent (S) from the coated film, A polyimide film is manufactured by a method that includes [a specific component].

[0138] The method for applying polyimide varnish to a substrate is not particularly limited. For example, a coating film can be formed by applying polyimide varnish to a substrate to a desired thickness using contact transfer type coating equipment such as a roll coater, reverse coater, bar coater, or slit coater, or non-contact type coating equipment such as a spinner (rotary coating device) or curtain flow coater.

[0139] After forming a coating film made of polyimide varnish by the method described above, the coating film is baked to remove the organic solvent (S) and form a polyimide film. The baking temperature is determined appropriately considering the boiling point of the organic solvent (S) and the heat resistance of the polyimide resin (A). The baking may be carried out at a low temperature under reduced pressure.

[0140] The baking method is not particularly limited and may include any of the following: (i) 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 a period of 60 seconds to 500 seconds; (ii) leaving it at room temperature for a period of several hours to several days; or (iii) removing the organic solvent (S) by placing the substrate in a hot air heater or infrared heater for a period of several tens of minutes to several hours.

[0141] The coating film formed as described above may be post-baked after the removal of the organic solvent (S). For post-baking, the upper temperature limit is preferably 300°C or less, and more preferably 280°C or less. The lower temperature limit is preferably 120°C or higher, and more preferably 130°C or higher.

[0142] The thickness of the polyimide film formed as described above is not particularly limited and can be determined appropriately depending on the application. Typically, the thickness of the polyimide film is preferably 2 μm to 500 μm, and more preferably 5 μm to 50 μm.

[0143] If the polyimide varnish contains a photoinitiator (C), a patterned polyimide film can be obtained by forming a coated film using the method described above, followed by exposure and development of the coated film. In other words, the process involves a coating step in which a polyimide varnish containing a photoinitiator (C) is applied to a substrate to form a coated film, An organic solvent removal step, which removes at least a portion of the organic solvent (S) from the coated film, A patterning step involves exposing and developing a coated film from which at least a portion of the organic solvent (S) has been removed. A patterned polyimide film is manufactured by a method that includes [the specified method].

[0144] In the method for producing the patterned polyimide film described above, the application of polyimide varnish and the heating of the coated film to remove the organic solvent (S) are carried out according to the method described above.

[0145] The conditions for exposing polyimide varnish are not particularly limited as long as the curing proceeds well. Exposure is performed, for example, by irradiating with active energy rays such as ultraviolet light or excimer laser light. There are no particular restrictions on the amount of energy irradiated, but for example, 30 mJ / cm² is acceptable. 2 More than 5000mJ / cm 2 The following are examples: After exposure, the exposed coating film may be baked using the same method as the heating method after coating.

[0146] The development method is not particularly limited, and methods such as immersion or spraying can be used. A specific example of a developer is an organic solvent (S) that may be contained in the polyimide varnish.

[0147] After development, if necessary, the developed coating film can be rinsed with pure water or baked to obtain a patterned polyimide film. The baking conditions after development are preferably between 150°C and 280°C, and more preferably between 180°C and 230°C. The baking time after development is preferably between 5 minutes and 12 hours, more preferably between 10 minutes and 6 hours, and particularly preferably between 30 minutes and 1 hour. [Examples]

[0148] The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0149] [Example 1] 31.15 g of 4,4'-(4-aminophenyloxy)biphenyl (BPAB) as the diamine component and 294 g of N-methyl-2-pyrrolidone (NMP) were added to a three-necked flask equipped with a Dean-Stark trap. The contents of the flask were stirred at 40°C to dissolve BPAB in NMP. To the resulting solution, 40 g of 2,2-bis[4-(3,4-dicarboxyphenyloxy)phenyl]propane dianhydride (BPADA) as the tetracarboxylic dianhydride component was gradually added, ensuring that the liquid temperature did not exceed 50°C. After the addition of BPADA was complete, the reaction mixture was stirred at 40°C for 2 hours. Next, 30 g of toluene was added to the reaction mixture. Then, the reaction mixture was stirred at 180°C for 6 hours, while removing the generated water using a Dean-Stark trap. After 6 hours, toluene was removed from the reaction mixture by distillation. Next, the reaction mixture was cooled to room temperature to obtain an NMP solution of polyimide resin containing a polyimide resin formed by the ring closure of a polyamic acid obtained by the condensation of BPADA and BPAB. Furthermore, the disappearance of the amide bond 1 Imidization was confirmed by H-NMR. [ka]

[0150] [Example 2] An NMP solution of polyimide resin was obtained in the same manner as in Example 1, except that 40 g of BPADA was replaced with 34.14 g of 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride (see below 6FDA). The solution contained a polyimide resin formed by the cyclization of a polyamic acid obtained by the condensation of 6FDA and BPAB. [ka]

[0151] [Comparative Example 1] Polyimide resin was synthesized in the same manner as in Example 1, except that BPAB was replaced with 4,4'-diamidiphenyl ether (ODA below) in an equimolar amount with BPAB, and BPADA was replaced with pyromellitic dianhydride (PMDA below) in an equimolar amount with BPADA. However, gelation occurred during the reaction, and precipitation occurred. As a result, a solution of polyimide resin could not be obtained. [ka]

[0152] Since a polyimide resin solution could not be obtained using the above method, a polyamic acid solution formed by the condensation of ODA and PMA was prepared by the following method in order to form a polyimide resin film for evaluation.

[0153] 40.39 g of ODA and 490 g of N-methyl-2-pyrrolidone (NMP) were added to a three-necked flask. The contents of the flask were stirred at 40°C to dissolve the ODA in the NMP. 40 g of PMDA, as the tetracarboxylic dianhydride component, was gradually added to the resulting solution, ensuring that the liquid temperature did not exceed 50°C. After the addition of PMDA was complete, the reaction mixture was stirred at 40°C for 6 hours. The reaction mixture was then cooled to room temperature to obtain an NMP solution of polyamic acid formed by the condensation of PMDA and ODA.

[0154] [Comparative Example 2] An NMP solution of polyimide resin was obtained in the same manner as in Example 1, except that BPAB 31.15 g was replaced with 4,4'-diamidiphenylsulfone (DSA below) 20.9 g. The solution contained a polyimide resin formed by the cyclization of a polyamic acid obtained by the condensation of BPADA and DSA. [ka]

[0155] Using the NMP solutions of polyimide resin or polyamic acid obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2, polyimide resin films were formed by the following method. Tensile tests and dielectric property measurements were performed on the formed polyimide resin films according to the following method. These evaluation results are shown in Table 1.

[0156] <Filmization> In Examples 1 and 2, and Comparative Example 2, an NMP solution of polyimide resin was applied to a silicon wafer using a spin coater, and the applied film was heated at 180°C for 1 hour to form a polyimide resin film. The formed polyimide resin film was peeled 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. Furthermore, the imidization rate of the polyimide resin films obtained by the above method using the NMP solutions of the polyimide resins obtained in Example 1, Example 2, and Comparative Example 2 was 95% or higher in all cases. The imidization rate 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. In the FT-IR spectrum of a film heated at 350°C, at wavenumber 1380 cm⁻¹... -1 Peak height H of imide stretching vibration 01 And, the height of the aromatic peak H 02Therefore, the ratio of the two is H 01 / H 02 The value of was calculated. Next, in the FT-IR spectrum of the film not heated at 350°C, wavenumber 1380 cm⁻¹ -1 Peak height H of imide stretching vibration 11 And, the height of the aromatic peak H 12 Therefore, the ratio of the two is H 11 / H 12 The value of was calculated. H 01 / H 02 The value and H 11 / H 12 The imidization rate was measured from the values ​​according to the following formula. Imidization rate (%) = (H 11 / H 12 ) / (H 01 / H 02 ) × 100

[0157] In Comparative Example 1, a polyamic acid NMP solution was applied to a silicon wafer using a spin coater, and the applied film was heated at 350°C for 4 hours to form a polyimide resin film. The formed polyimide resin film was peeled 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.

[0158] <Tensile Test> From the obtained polyimide resin film, strip-shaped test pieces measuring 1 cm in width and 5 cm in length were cut. Tensile tests were performed on the obtained test pieces using a tensile testing machine (EZ-test, manufactured by Shimadzu Corporation) under the conditions of a chuck distance of 2 cm and a tensile speed of 1 mm / min, and the tensile elongation and tensile strength were measured. The tensile elongation was calculated according to the following formula. Tensile elongation (%) = (Distance between chucks at break (cm) / 2 (cm) - 1) × 100 For tensile elongation, values ​​of 10% or more were judged as ○, values ​​between 8% and 10% were judged as △, and values ​​below 8% were judged as ×. For tensile strength, values ​​of 90 MPa or higher were judged as "○" and values ​​below 90 MPa were judged as "×".

[0159] <Measurement of dielectric properties> The dielectric constant (ε) and dielectric loss tangent (tanδ) of the obtained samples were measured using the method described in "Study on Millimeter-Wave Complex Dielectric Constant Evaluation of Photosensitive Insulating Films by Cylindrical Cavity Resonator Method" (Kohei Takahagi (Utsunomiya University), Kazuaki Ebisawa (Tokyo Ohka Kogyo Co., Ltd.), Yoshinori Furukami (Utsunomiya University), Takashi Shimizu (Utsunomiya University)), IEICE Technical Report vol. 118, no. 506, MW2018-158, pp. 13-18, March 2019. A network analyzer HP8510C (Keysight Corporation) was used to measure the values ​​using the cavity resonator method under the conditions of room temperature 25°C, humidity 50%, frequency 36GHz, and sample thickness 10μm. A value of less than 3.00 was judged as ○, and a value of 3.00 or greater was judged as ×. A dielectric loss tangent value of less than 0.01 was judged as "○" (correct), and a value of 0.01 or greater was judged as "×" (incorrect).

[0160] [Table 1]

[0161] Examples 1 and 2 show that a polyimide resin containing the specific structural unit represented by formula (A1) above dissolves well in organic solvents such as NMP, and provides a polyimide resin film with excellent mechanical properties and dielectric properties in the high-frequency band. Furthermore, when using a varnish containing polyamic acid, as in Comparative Example 1, heating at a high temperature of 350°C is required to form the polyimide resin film. However, when using a varnish in which the polyimide resin is dissolved, as in Examples 1 and 2, the polyimide resin film can be manufactured simply by heating at a low temperature of around 150-200°C to remove the organic solvent.

[0162] [Example 3] In a three-necked flask, 15.57 g of BPAB as the diamine component, 6.43 g of 3,5-diaminobenzoic acid (DABA below), and 250 g of NMP were added. The contents of the flask were then stirred to dissolve BPAB and DABA in NMP. Subsequently, 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. Then, 0.88 g of 5-norbornene-2,3-dicarboxylic acid anhydride was added to the reaction mixture as a terminal encapsulant, and the reaction mixture was stirred at room temperature for 4 hours to obtain polyamic acid. The numbers in parentheses in the following formulas represent the molar ratio (mol%) of each constituent unit in the resin. <Polyamic acid production> [ka]

[0163] 33 g of carbodiimidazole was added to a reaction solution containing polyamic acid, and the reaction solution was stirred at room temperature for 4 hours to convert the polyamic acid into polyimide resin. The reaction solution, after stirring, was added dropwise to 5 kg of water to generate a precipitate. The resulting 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 carboxyl groups, consisting of the constituent units shown in the following formula. <Imidization> [ka]

[0164] In a three-necked flask, the obtained polyimide resin having a carboxyl group, 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, and the reaction mixture was stirred at room temperature for 6 hours. The reaction solution, after stirring, was added dropwise to 2 kg of methanol to generate a precipitate. The resulting 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 methacryloyl groups at the end of the side chains, consisting of the constituent units shown in the following formula. Regarding the obtained polyimide resin 1 ¹H-NMR measurements were performed, and imidization was confirmed by the disappearance of the peak corresponding to the amide bond. Based on the integral ratio of the total aromatics and the integral ratio of the double bond, it was confirmed that a theoretical amount of methacryloyl groups had been introduced into the polyimide resin.

[0165] <Introduction of methacryloyl group> [ka]

[0166] [Example 4] A polyimide resin with the structure shown in the following formula was synthesized in the same manner as in Example 3, 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 ¹H-NMR measurements were performed, and imidization was confirmed by the disappearance of the peak corresponding to the amide bond. Based on the integral ratio of the total aromatics and the integral ratio of the double bond, it was confirmed that a theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0167] [Example 5] A polyimide resin with the structure shown in the following formula was synthesized in the same manner as in Example 3, 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 1¹H-NMR measurements were performed, and imidization was confirmed by the disappearance of the peak corresponding to the amide bond. Based on the integral ratio of the total aromatics and the integral ratio of the double bond, it was confirmed that a theoretical amount of methacryloyl groups had been introduced into the polyimide resin. [ka]

[0168] [Examples 6-11] 100 parts by mass of the polyimide resin of the type listed in Table 2 was dissolved in NMP to a concentration of 20% by mass. To the resulting solution, 5 parts by mass of Irgacure OXE01 (manufactured by BASF Japan), an oxime ester-based 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 obtain the photosensitive compositions of each example. The photosensitive compositions of Examples 9 to 11 were further supplemented with the types and amounts of photopolymerizable monomers listed in Table 2. The photopolymerizable monomers listed in Table 2 are as follows: M1: Dimethylol tricyclodecanediaacrylate M2: Dipentaerythritol hexaacrylate

[0169] The obtained photosensitive composition was used to form a film according to the following method. The imidization rate of the obtained film was confirmed using the same method as in Example 1. After applying the photosensitive composition onto a silicon wafer using a spin coater, the formed coating film was exposed to a high-pressure mercury lamp at an exposure dose of 2000 mJ / cm². 2 The material was exposed to light. After exposure, the coated film was heated at 180°C for 1 hour to form a polyimide resin film. Using a 1% by mass aqueous solution of hydrofluoric acid, the formed polyimide resin film was peeled from the silicon wafer to obtain a polyimide resin film. The thickness of the obtained polyimide resin film was 20 μm. The imidization rates of the polyimide resin films obtained using the photosensitive compositions of Examples 6 to 11 were all 95% or higher.

[0170] Furthermore, except for changing the film thickness to 10 μm, the film obtained using the same method as described above was used as a sample, and dielectric properties were measured in the same manner as in Example 1. The evaluation results of the dielectric properties based on the dielectric properties measurement results are shown in Table 2.

[0171] Furthermore, the photosensitivity of the obtained photosensitive compositions was evaluated according to the following method. First, a photosensitive composition was spin-coated onto a copper wafer to form a coated film, which was then baked at 80°C for 300 seconds. The spin rate during spin-coating was adjusted so that the film thickness after baking was 10 μm. The baked coating film is exposed to an exposure dose of 100 mJ / cm² through a negative mask for hole formation, which has a roughly square opening of 50 μm × 50 μm in size. 2 From 4000 mJ / cm 2 Exposure was performed with a focus of 0 μm until the image was fully exposed. The exposed coating film was developed by immersing it in cyclopentanone for 60 seconds. The developed coating film was observed using a scanning electron microscope (SEM). A result of ○ was given if a hole with a roughly square opening of 50 μm × 50 μm size was formed, and a result of × was given if any other result was not ○.

[0172] [Table 2]

[0173] Examples 6 to 11 show that a polyimide resin containing the specific structural unit represented by formula (A1) and having polymerizable groups such as methacryloyl groups dissolves well in organic solvents such as NMP, exhibits good photosensitivity, and provides a polyimide resin film with excellent dielectric properties.

Claims

[Claim 1] A polyimide varnish comprising a polyimide resin (A) containing a structural unit represented by the following formula (A1) in its molecular chain, and an organic solvent (S). 【Chemistry 1】 (In formula (A1), X １ and X ２ Each of these is independently a divalent organic group, Y １ R is a tetravalent organic group, ａ１ and R ａ２ Each of these is independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n1 and n2 are independently integers between 0 and 4.

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