Varnish composition and method for producing polyimide film

Abstract

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

Description

Technical Field

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

Background Art

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

[0003] In recent years, communication devices such as mobile phones have been operating at higher frequencies. Therefore, insulation parts that insulate metal wiring in communication devices are also required to cope with higher frequencies. Here, the higher the frequency, the greater the transmission loss, and when the transmission loss increases, the electrical signal attenuates. Therefore, in order to cope with higher frequencies, it is required to reduce the transmission loss. In this regard, polyimide resins exhibit a low dielectric tangent and a low dielectric constant in the high-frequency band and have excellent high-frequency characteristics. For this reason, polyimide resins have attracted attention as materials that can reduce transmission loss in various substrates and elements used in the high-frequency band.

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

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0007] Under the above circumstances, there is a demand for a polyimide resin that is soluble in an organic solvent and has photosensitivity that can be cured by the action of a photosensitive curing agent. When such a polyimide resin is used, a photosensitive varnish in which the photosensitive polyimide resin is dissolved in an organic solvent can be obtained. When using such a photosensitive varnish, after applying the varnish to a substrate or the like and then removing the organic solvent from the coating film, a polyimide resin having a fine and precise shape can be formed by a photolithography method. According to this method, a polyimide resin is formed without performing heating at a high temperature.

[0008] The present invention has been made in view of the above problems, and provides a polyimide resin that is soluble in an organic solvent, has photosensitivity that can be cured by the action of a photosensitive curing agent, and gives a cured product having excellent dielectric properties in a high-frequency band, a varnish composition containing the polyimide resin, and a method for manufacturing a polyimide film using the varnish composition.

Means for Solving the Problems

[0009] The inventors of the present invention have found that the above problems can be solved by bonding a radical polymerizable group or a cationic polymerizable group to the main chain of a polyimide resin and including a skeleton derived from bisphenols having a specific structure in the structural units constituting the main chain of the polyimide resin, and have thus completed the present invention. More specifically, the present invention provides the following.

[0010] A first aspect of the present invention is the following formula (A1a):

Chemical formula

Chemical formula

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

[0012] A third aspect of the present invention is a coating step of coating the varnish composition according to the second aspect on a substrate to form a coating film, and an organic solvent removing step of removing at least a part of the organic solvent (S) from the coating film, which is a method for producing a polyimide film.

Advantages of the Invention

[0013] According to the present invention, there can be provided a polyimide resin that is soluble in an organic solvent, has photosensitivity capable of being cured by the action of a photosensitive curing agent, and gives a cured product having excellent dielectric properties in a high-frequency band, a varnish composition containing the polyimide resin, and a method for producing a polyimide film using the varnish composition.

Embodiments for Carrying Out the Invention

[0014] ≪Polyimide Resin≫ The polyimide resin has a molecular chain containing a structural unit represented by the following formula (A1a):

Chemical Formula

[0015] In the above formula (A1a), at least one of the divalent organic group as X 1 and the tetravalent organic group as Y 1 is represented by the following formula (a1):

Chemical Formula

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

[0017] The molecular chain of the above polyimide resin contains a radical polymerizable group or a cationic polymerizable group. Therefore, the above polyimide resin can be cured by the action of an initiator such as a radical polymerization initiator or a cationic polymerization initiator and insolubilized in an organic solvent.

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

[0019] The amount of the radically polymerizable group or cationically polymerizable group in the polyimide resin is not particularly limited as long as it does not inhibit the object of the present invention. The amount of the radically polymerizable group or cationically polymerizable group in the polyimide resin is preferably, for example, 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, in terms of the number of moles of the functional group relative to the weight of the polyimide resin. The amount of the radically polymerizable group or cationically polymerizable group in the polyimide resin can typically be measured by NMR analysis.

[0020] The above-mentioned radically polymerizable group is preferably bonded to the aromatic ring in the molecular chain of the polyimide resin. Suitable examples of the radically polymerizable group bonded to the aromatic ring in the molecular chain of the polyimide resin include groups represented by the following formula (A1) or the following formula (A2) and not corresponding to a vinyloxy group-containing group. -(A 01 ) na -R 01 ···(A1) -(A 01 ) na -R 02 -A 02 -R 01 ···(A2)

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

[0022] Preferable specific examples of the radical polymerizable group bonded to the aromatic ring in the main chain include -O-R 03 , -O-CH2CH2-O-R 03 , -O-CH2CH2CH2-O-R 03 , -O-CH2CH2CH2CH2-O-R 03 , -CO-O-CH2CH2-O-R 03 , -CO-O-CH2CH2CH2-O-R 03 , -CO-O-CH2CH2CH2CH2-O-R 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-R03 , -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 exemplified. R in these groups 03 is an allyl group or a (meth)acryloyl group.

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

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

[0025] Preferred specific examples of the cation-polymerizable group bonded to the aromatic ring in the main chain include -R 07 , -O-CH2CH2-R 07 , -O-CH2CH2CH2-R 07 , -O-CH2CH2CH2CH2-R 07 , -CO-O-CH2CH2-R 07 , -CO-O-CH2CH2CH2-R 07 , -CO-O-CH2CH2CH2CH2-R07 , -NH-CH2CH2-R 07 , -NH-CH2CH2CH2-R 07 , -NH-CH2CH2CH2CH2-R 07 , -CO-NH-CH2CH2-R 07 , -CO-NH-CH2CH2CH2-R 07 , and -CO-NH-CH2CH2CH2CH2-R 07 include groups represented by the following. R in these groups 07 is a vinyloxy group, glycidyloxy group, epoxycyclopentyl group, epoxycyclohexyl group, or epoxycycloheptyl group.

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

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

[0028] In formula (a1), n1 and n2 are each independently an integer of 0 or more and 4 or less. Since it is easy to obtain the monomer compound for producing the polyamic acid which is a precursor of the polyimide resin, etc., n1 and n2 are each preferably an integer of 0 or more and 2 or less, and more preferably 0.

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

[0030] Preferable specific examples of the partial structure represented by formula (a1) include the following structures. [Chemical formula]

[0031] The molecular chain of the polyimide resin has, as a structural unit represented by formula (A1a), the following formula (A1b): [Chemical formula] (In formula (A1b), X 2 and X 3 are each independently a divalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom, Y 2 is a tetravalent organic group having no partial structure represented by formula (a1), R a1 , R a2 , R a3 , R a4, n1, and n2 are the same as these in formula (a1).) A structural unit represented by the following formula (A1c):

Chemical formula

Chemical formula

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

[0033] X 2 and X 3 The number of carbon atoms of the aromatic hydrocarbon group as X and X is not particularly limited. For example, 6 or more and 50 or less is preferred, and 6 or more and 20 or less is more preferred. Note that the number of carbon atoms of the aforementioned aromatic hydrocarbon group does not include the number of carbon atoms of the substituent. X 2 and X 3 Examples of the aromatic hydrocarbon group as X and X include phenylene groups such as an o-phenylene group, an m-phenylene group, and a p-phenylene group, naphthalenediyl groups such as a naphthalene-1,4-diyl group, a naphthalene-1,3-diyl group, a naphthalene-2,6-diyl group, and a naphthalene-2,7-diyl group, and biphenyldiyl groups such as a biphenyl-4,4'-diyl group, a biphenyl-3,4'-diyl group, and a biphenyl-3,3'-diyl group.

[0034] X 2 and X 3Examples thereof preferably include a p-phenylene group, an m-phenylene group, a naphthalene-1,4-diyl group, and a biphenyl-4,4'-diyl group; more preferably include a p-phenylene group and a biphenyl-4,4'-diyl group; and even more preferably include a p-phenylene group.

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

[0036] In formula (a1-1), A 1 is a tetravalent organic group having 6 to 50 carbon atoms and may have one or more substituents in addition to the two acid anhydride groups represented by -CO-O-CO- in formula (a1-1). Preferable examples of the substituent include a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a fluorinated alkyl group having 1 to 6 carbon atoms, and a fluorinated alkoxy group having 1 to 6 carbon atoms. Further, the compound represented by formula (a1-1) may contain a carboxy group or a carboxylic acid ester group in addition to the acid anhydride group. When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, a perfluoroalkyl group or a perfluoroalkoxy group is preferable. The same applies to the above substituents and also to one or more substituents that an aromatic group described later may have on an aromatic ring.

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

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

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

[0040] Further, A in formula (a1-1) 1 As the aliphatic group constituting the following tetravalent group represented by the formula (a2) can be employed, for example. When using such a group, there is a tendency to easily obtain a polyimide resin having excellent transparency. Note that, from the viewpoint of easy purification of the raw material compound, a in formula (a2) is preferably 5 or less, more preferably 3 or less. Further, since the chemical stability of the raw material compound giving the structural unit represented by formula (a1) is excellent, a is preferably 1 or more, more preferably 2 or more. a in formula (a2) is particularly preferably 2 or 3. [Chemical formula] (In formula (a2), R a11 , R a12 , and R a13 are each independently one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and a fluorine atom, and a is an integer of 0 or more and 12 or less.)

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

[0042] Examples of the aromatic tetracarboxylic dianhydrides may also include, for example, compounds represented by the following general formulas (a1-2) to (a1-4).

Chemical formula

[0043] In the above formulas (a1-2) and (a1-3), R a01 , R a02 and R a03 each represent 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 divalent group composed of a combination thereof. R a02 and R a03 may be the same or different. That is, R a01 , R a02 and R a03 may contain a carbon-carbon single bond, a carbon-oxygen-carbon ether bond, or a halogen element (fluorine, chlorine, bromine, iodine). Examples of the compound represented by the formula (a1-2) include 2,2-bis(3,4-dicarboxyphenoxy)propane dianhydride and 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride.

[0044] Further, in the above formula (a1-4), R a04 , R a05represents a monovalent substituent composed 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. R a04 , and R a05 may be the same or different from each other. As the compound represented by the formula (a1-4), difluoropyromellitic dianhydride, dichloropyromellitic dianhydride and the like can also be used.

[0045] In addition, the polyimide resin has a radically polymerizable group or a cationically polymerizable group on its molecular chain. Therefore, the tetravalent organic group Y 2 in the formula (A1b) may be a group represented by the following formula (A1-1) to formula (A1-3).

Chemical formula

[0046] Examples of the reaction for introducing a radically polymerizable group or a cationically polymerizable group include 1) The etherification reaction between a halogen atom bonded to an aromatic ring in a polyamic acid or a polyimide resin molecule chain and an alcohol compound having a radical polymerizable group or a cationic polymerizable group, 2) The esterification reaction between a hydroxyl group bonded to an aromatic ring in a polyamic acid or a polyimide resin molecule chain and a carboxylic acid halide having a radical polymerizable group or a cationic polymerizable group, 3) The esterification reaction between a carboxy group bonded to an aromatic ring in a polyimide resin molecule chain and an organic halide having a radical polymerizable group or a cationic polymerizable group, and 4) The N-substitution reaction between an amino group bonded to an aromatic ring in a polyamic acid or a polyimide resin molecule chain and an organic halide having a radical polymerizable group or a cationic polymerizable group, etc. are exemplified. The reactions for introducing a radical polymerizable group or a cationic polymerizable group are not limited to these reactions.

[0047] In addition, after synthesizing a polyamic acid or a polyimide resin having a hydroxyl group protected by a protecting group such as an acetyl group, a carboxylic acid ester group such as a methoxycarbonyl group, an amino group protected by a protecting group such as a tert-butoxycarbonyl group, etc. on the aromatic ring, deprotection is carried out by a well-known method to obtain a polyamic acid or a polyimide resin having a hydroxyl group, a carboxy group, or an amino group, etc. on the aromatic ring.

[0048] Y in formula (A1c) 3 and Y 4 are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. Preferable examples of the alkyl group having 1 to 4 carbon atoms, the alkoxy group having 1 to 4 carbon atoms, and the halogen atom as substituents are the same as the preferable examples of the substituents which the aromatic hydrocarbon group as X 2 and X 3 in formula (A1b) may have.

[0049] Y3 and Y 4 The number of carbon atoms of the aromatic hydrocarbon group as [group name] is not particularly limited, and for example, 6 or more and 50 or less is preferable, and 6 or more and 20 or less is more preferable. Note that the number of carbon atoms of the aforementioned aromatic hydrocarbon group does not include the number of carbon atoms of the substituent. Y 3 and Y 4 Examples of the aromatic hydrocarbon group as [group name] include benzene triyl groups such as benzene-1,2,3-triyl group and benzene-1,2,4-triyl group, naphthalene triyl groups such as naphthalene-1,2,4-triyl group, naphthalene-2,3,6-triyl group, and naphthalene-1,3,8-triyl group, and biphenyl triyl groups such as biphenyl-3,4,4'-triyl group and biphenyl-3,4,3'-triyl group.

[0050] Y 3 and Y 4 Examples of [group name] include benzene-1,2,3-triyl group, benzene-1,2,4-triyl group, biphenyl-3,4,4'-triyl group, and biphenyl-3,4,3'-triyl group, with benzene-1,2,4-triyl group and biphenyl-3,4,4'-triyl group being more preferable, and benzene-1,2,4-triyl group being even more preferable.

[0051] X in formula (A1c) 4 is a divalent organic group that does not have the partial structure represented by formula (a1). X 4 The divalent organic group as [group name] is typically a divalent organic residue derived from a diamine used as a raw material for a polyamic acid, which is a precursor of a polyimide resin. Examples of the diamine that provides the divalent organic residue include compounds represented by the following formula (a3-1). A compound represented by the following formula (a3-1) can typically be used. The diamine compound may be used alone 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 2The divalent organic group as such does not contain the partial structure represented by the formula (a1).)

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

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

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

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

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

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

[0058] As Q in Formula (24), from the viewpoint of the heat resistance of the formed polyimide resin, a 9,9'-fluorenylidene group, -O-C6H4-O-, -C(CF3)2-, -O-, -C(CH3)2-, -CH2-, or -CONH- is preferable.

[0059] When an aromatic diamine is used as the diamine compound represented by Formula (a3-1), for example, the following aromatic diamines can be preferably used. That is, as the aromatic diamine, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl methane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 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, etc. may be mentioned. Among these, from the viewpoints of price, availability, etc., p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenyl ether, and 4,4'-diaminobenzanilide are preferable.

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

Chemical formula

[0061] Also, from the viewpoint of further improving the mechanical properties of the obtained polyimide resin, as A 2 a group represented by the following formula (Si-1) can also be preferably used.

Chemical formula

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

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

[0064] Regarding R in formula (Si-1)114 , R 115 , R 116 , and R 117 As for the alkyl group having 1 to 20 carbon atoms in R, an alkyl group having 1 to 10 carbon atoms is preferable from the viewpoints of heat resistance and residual stress. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, etc. may be mentioned. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 As for the cycloalkyl group having 3 to 20 carbon atoms in R, a cycloalkyl group having 3 to 10 carbon atoms is preferable from the viewpoints of heat resistance and residual stress. Specifically, a cyclopentyl group, a cyclohexyl group, etc. may be mentioned. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 As for the aryl group having 6 to 20 carbon atoms in R, an aryl group having 6 to 12 carbon atoms is preferable from the viewpoints of heat resistance and residual stress. Specifically, a phenyl group, a tolyl group, a naphthyl group, etc. may be mentioned. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 As for the group containing an amino group having 20 or less carbon atoms in R, an amino group, a substituted amino group (for example, a bis(trialkylsilyl)amino group), etc. may be mentioned. R in formula (Si-1) 114 , R 115 , R 116 , and R 117 As for the group represented by -O-R in R 118 , a methoxy group, an ethoxy group, a propoxy group, an isopropyloxy group, a butoxy group, a phenoxy group, a tolyloxy group, a naphthyloxy group, a propenyloxy group (for example, an allyloxy group), and a cyclohexyloxy group, etc. may be mentioned. Among them, R 114 , R 115 , R 116 , and R117 Preferably, it is a methyl group, an ethyl group, a propyl group, or a phenyl group.

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

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

[0067] The organic group X having a radically polymerizable group or a cationically polymerizable group 4 Preferable specific examples of include the following groups.

Chemical formula

[0068]

Chemical formula

[0069]

Chemical formula

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

[0071] In formula (A1d), Y 5 and Y 6 are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. Y 5 and Y 6 as the trivalent aromatic hydrocarbon group is the same as the trivalent aromatic hydrocarbon group as Y 3 and Y 4 in formula (A1c).

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

[0073] As the structural unit represented by formula (A1a), the structural unit represented by formula (A1c) is preferred because the synthesis and availability of the raw materials for synthesizing the polyimide resin are easy, or the introduction of a radical polymerizable group or a cationic polymerizable group into the structural unit is easy, etc. The ratio of the mass of the structural unit represented by formula (A1c) to the mass of the structural unit represented by formula (A1a) is preferably 50% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0074] The polyimide resin may contain a structural unit represented by the following formula (A1e) as long as it does not inhibit the object of the present invention. The structural unit represented by the following formula (A1e) does not have the partial structure represented by the aforementioned formula (a1). [Chemical formula] (In formula (A1e), X 4 is the same as X in formula (A1c), 4 and Y 2 is the same as Y in formula (A1b).) 2

[0075] The method for producing the polyimide resin described above is not particularly limited. The polyimide resin described above can typically be produced by reacting a polyamic acid having a structure corresponding to the structure of the above structural unit with a tetracarboxylic dianhydride to obtain a polyamic acid, and then imidizing the polyamic acid. When producing the polyamic acid, the tetracarboxylic dianhydride and the diamine may each be used alone or in combination of two or more. As described above, the polyimide resin has a radical polymerizable group or a cationic polymerizable group. The radical polymerizable group or the cationic polymerizable group may be introduced onto the molecular chain after the synthesis of the polyamic acid or after the synthesis of the polyimide resin. When introducing a radical polymerizable group or a cationic polymerizable group onto the molecular chain of the polyamic acid or the polyimide resin (A) after the synthesis of the polyamic acid or after the synthesis of the polyimide resin (A), the introduction method is not particularly limited. Since a carboxyl group, an amide bond, and a radical polymerizable group or a cationic polymerizable group are likely to cause undesirable side reactions, it is more preferable to introduce a radical polymerizable group or a cationic polymerizable group into the polyimide resin (A) than into the polyamic acid. ​Typical examples of methods for introducing a radically polymerizable group or a cationically polymerizable group onto a molecular chain include a polyamic acid or a polyimide resin (A) having a functional group such as a hydroxyl group, an amino group, or a carboxy group, and a carboxylic acid having a radically polymerizable group, a carboxylic acid halide having a radically polymerizable group, an alcohol having a radically polymerizable group, a phenol having a radically polymerizable group, an amine having a radically polymerizable group, a halogenated compound having a radically polymerizable group, a carboxylic acid having a cationically polymerizable group, a carboxylic acid halide having a cationically polymerizable group, an alcohol having a cationically polymerizable group, a phenol having a cationically polymerizable group, an amine having a cationically polymerizable group, or a halogenated compound having a cationically polymerizable group, which are reacted by a known method such as a condensation reaction using a well-known condensing agent or a Williamson etherification reaction.

[0076] When synthesizing polyamic acid, the amounts of the tetracarboxylic dianhydride and the diamine compound used are not particularly limited, but it is preferable to use 0.50 mol or more and 1.50 mol or less of the diamine compound with respect to 1 mol of the tetracarboxylic dianhydride, more preferably 0.60 mol or more and 1.30 mol or less, and particularly preferably 0.70 mol or more and 1.20 mol or less. Also, the weight average molecular weight of the obtained polyamic acid may be appropriately set according to its 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 obtained polyamic acid is, for example, 100000 or less, preferably 80000 or less, and more preferably 75000 or less. This weight average molecular weight may be adjusted to the above values by adjusting the blending amounts of the tetracarboxylic dianhydride and the diamine compound, and the reaction conditions such as the solvent and the reaction temperature.

[0077] The reaction between a tetracarboxylic dianhydride and a diamine compound is usually carried out in an organic solvent. The organic solvent used in the reaction between a tetracarboxylic dianhydride and a diamine compound is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride and the diamine compound and does not react with the tetracarboxylic dianhydride and the diamine compound. The organic solvent can be used alone or in a mixture of two or more.

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

[0079] Among these organic solvents, nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylcaprolactam, and N,N,N',N'-tetramethylurea are preferred from the viewpoint of the solubility of the resulting polyamic acid and polyimide resin.

[0080] The temperature at which the tetracarboxylic dianhydride and the diamine compound are reacted is not particularly limited as long as the reaction proceeds well. Typically, the reaction temperature between the tetracarboxylic dianhydride and the diamine compound is preferably -5°C or higher and 150°C or lower, more preferably 0°C or higher and 120°C or lower, and particularly preferably 0°C or higher and 70°C or lower. The reaction time for reacting the tetracarboxylic dianhydride and the diamine compound varies depending on the reaction temperature, but typically, it is preferably 1 hour or longer and 50 hours or shorter, more preferably 2 hours or longer and 40 hours or shorter, and particularly preferably 5 hours or longer and 30 hours or shorter.

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

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

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

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

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

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

[0087] When the polyimide resin (A) has a radically polymerizable group, the varnish composition may contain, together with the polyimide resin (A), a monomer compound (B) that is a monomer compound having an ethylenically unsaturated double bond. Such a monomer compound may be a monofunctional monomer compound or a polyfunctional monomer compound, and a polyfunctional monomer compound is preferable.

[0088] Examples of the 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-acrylamido-2-methylpropanesulfonic acid, tert-butylacrylamidosulfonic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 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)acrylate of phthalic acid derivatives. These monofunctional photopolymerizable monomers can be used alone or in combination of two or more kinds.

[0089] Examples of the 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 - hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 2,2 - bis(4-(meth)acryloxydiethoxyphenyl)propane, 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, phthalic acid diglycidyl ester di(meth)acrylate, glycerin triacrylate, glycerin polyglycidyl ether poly(meth)acrylate, urethane (meth)acrylate (i.e., tolylene diisocyanate), reaction product of trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and 2 - hydroxyethyl (meth)acrylate, methylene bis(meth)acrylamide, (meth)acrylamide methylene ether, condensate of polyhydric alcohol and N - methylol(meth)acrylamide, and other polyfunctional monomer compounds such as triacryl formal. These polyfunctional monomer compounds can be used alone or in combination of two or more.

[0090] Among these monomer compounds having ethylenically unsaturated double bonds, polyfunctional monomer compounds having three or more functional groups are preferred, polyfunctional monomer compounds having four or more functional groups are more preferred, and polyfunctional monomer compounds having five or more functional groups are even more preferred, because they tend to enhance the adhesion of the cured product to the substrate and the strength of the cured product.

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

[0092] Preferable specific examples of the vinyl ether compound include aromatic monovinyl ether compounds such as vinyl phenyl ether, 4 - vinyloxy toluene, 3 - vinyloxy toluene, 2 - vinyloxy toluene, 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, 1 - vinyloxy - 2,6 - dimethylbenzene, 1 - vinyloxy - 3,4 - dimethylbenzene, 1 - vinyloxy - 3,5 - dimethylbenzene, 1 - vinyloxy naphthalene, 2 - vinyloxy naphthalene, 2 - vinyloxy fluorene, 3 - vinyloxy fluorene, 4 - vinyloxy - 1,1'- biphenyl, 3 - vinyloxy - 1,1'- biphenyl, 2 - vinyloxy - 1,1'- biphenyl, 6 - vinyloxy tetralin, and 5 - vinyloxy tetralin; and aromatic divinyl ether compounds such as 1,4 - divinyloxy benzene, 1,3 - divinyloxy benzene, 1,2 - divinyloxy benzene, 1,4 - divinyloxy naphthalene, 1,3 - divinyloxy naphthalene, 1,2 - divinyloxy naphthalene, 1,5 - divinyloxy naphthalene, 1,6 - divinyloxy naphthalene, 1,7 - divinyloxy naphthalene, 1,8 - divinyloxy naphthalene, 2,3 - divinyloxy naphthalene, 2,6 - divinyloxy naphthalene, 2,7 - divinyloxy naphthalene, 1,2 - divinyloxy fluorene, 3,4 - divinyloxy fluorene, 2,7 - divinyloxy fluorene, 4,4'- divinyloxy biphenyl, 3,3'- divinyloxy biphenyl, 2,2'- divinyloxy biphenyl, 3,4'- divinyloxy biphenyl, 2,3'- divinyloxy biphenyl, 2,4'- divinyloxy biphenyl, and bisphenol A divinyl ether. These vinyl ether compounds may be used in combination of two or more kinds.

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

[0094] Also, oligomer or polymer type polyfunctional epoxy compounds can also be preferably used. Typical examples of oligomer or polymer type polyfunctional epoxy compounds include phenol novolak type epoxy compounds, brominated phenol novolak type epoxy compounds, orthocresol novolak type epoxy compounds, xylenol novolak type epoxy compounds, naphthol novolak type epoxy compounds, bisphenol A novolak type epoxy compounds, bisphenol AD novolak type epoxy compounds, epoxy compounds of dicyclopentadiene type phenol resins, epoxy compounds of naphthalene type phenol resins, and the like.

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

[0096] Specific examples of the alicyclic epoxy compound include 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-metha-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, trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), di(3,4-epoxycyclohexylmethyl) ether of ethylene glycol, 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).

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

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

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

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

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

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

[0103] Examples of the alicyclic epoxy compound represented by the above formula (b01-2) include m in the above formula (b01-2) a1The compound represented by the following formula (b01-2-1), which corresponds to the compound where [a certain condition] is 0, is preferable. [Chemical formula] (In formula (b01-2-1), R b01 ~R b012 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R b02 and R b010 may be bonded to each other to form a ring.)

[0104] [Chemical formula] (In formula (b01-3), R b01 ~R b010 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R b02 and R b08 may be bonded to each other.)

[0105] [Chemical formula] (In formula (b01-4), R b01 ~R b012 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R b02 and R b010 may be bonded to each other.)

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

[0107] In formulas (b01-1) to (b01-5), R b01 ~R b018When the organic group is an organic group, the organic group is not particularly limited as long as it does not inhibit the object of the present invention, and it may be a hydrocarbon group, a group composed of a carbon atom and a halogen atom, or a group containing a hetero atom such as a halogen atom, an oxygen atom, a sulfur atom, a nitrogen atom, or a silicon atom together with a carbon atom and a hydrogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom.

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

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

[0110] Specific examples of the halogenated hydrocarbon group 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.

[0111] Specific examples of the group consisting of a carbon atom, a hydrogen atom, and an oxygen atom 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; hydroxyaryl groups such as 2-hydroxyphenyl group, 3-hydroxyphenyl group, 4-hydroxyphenyl group, 2,3-dihydroxyphenyl group, 2,4-dihydroxyphenyl group, 2,5-dihydroxyphenyl 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; chain alkoxy groups such as 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, 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; chain alkenyloxy groups such as vinyloxy group, 1-propenyloxy group, 2-n-propenyloxy group (allyloxy group), 1-n-butenyloxy group, 2-n-butenyloxy group, and 3-n-butenyloxy group; 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; alkoxyalkoxy groups such as methoxymethoxy group, ethoxymethoxy group, n - propoxymethoxy group, 2 - methoxyethoxy group, 2 - ethoxyethoxy group, 2 - n - propoxyethoxy group, 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; aliphatic acyl groups such as formyl group, acetyl group, propionyl group, butanoyl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, and decanoyl group; aromatic acyl groups such as benzoyl group, α - naphthoyl group, and β - naphthoyl group; chain - like alkyloxycarbonyl groups such as 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; aryloxycarbonyl groups such as phenoxycarbonyl group, α - naphthoxycarbonyl group, and β - naphthoxycarbonyl group; aliphatic acyloxy groups such as formyloxy group, acetyloxy group, propionyloxy group, butanoyloxy group, pentanoyloxy group, hexanoyloxy group, heptanoyloxy group, octanoyloxy group, nonanoyloxy group, and decanoyloxy group; aromatic acyloxy groups such as benzoyloxy group, α - naphthoyloxy group, and β - naphthoyloxy group.;

[0112] R b01 ~R b018 is preferably a group independently 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 having excellent mechanical properties, R b01 ~R b018 is more preferably all hydrogen atoms.

[0113] In formulas (b01-2) to (b01-5), R b01 ~R b018 is the same as R b01 ~R b018 in formula (b01-1). In formulas (b01-2) and (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-.

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

Chemical formula

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

Chemical formula

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

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

[0118] Among the alicyclic epoxy compounds represented by formula (b01-5), specific examples of suitable compounds include 1,2,5,6-diepoxycyclooctane and the like.

[0119] Furthermore, the compound represented by the following formula (b1-I) can be suitably used as the epoxy compound.

Chemical formula

[0120] As the compound represented by the above formula (b1-I), the compound represented by the following formula (b1-II) is preferable.

Chemical formula

[0121] In formula (b1-II), the groups represented by R b20 and E 1 , R b21 and E 2 , and R b22 and E 3 are preferably such that at least two of them are each a group represented by the following formula (b1-IIa), and more preferably all of them are each a group represented by the following formula (b1-IIa). The groups represented by a plurality of formula (b1-IIa) bonded to one compound are preferably the same group.) -L-C a (b1-IIa) (In formula (b1-IIa), L is a group composed of a linear, branched or cyclic alkylene group, an arylene group, -O-, -C(=O)-, -NH- and combinations thereof, and C a is an oxiranyl group (epoxy group). In formula (b1-IIa), L and C a may be bonded to form a cyclic structure.)

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

[0123] 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), the organic groups represented by the following formulas (b1-IIb) to (b1-IId) can be mentioned.

Chemical formula

[0124] Hereinafter, examples of the compound represented by formula (b1-II) are shown as examples of an epoxy compound having an oxiranyl group or an alicyclic epoxy group, but are not limited thereto.

Chemical formula

[0125]

Chemical formula

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

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

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

[0129] Among siloxane compounds, a compound having a cyclic siloxane skeleton represented by the following formula (b1-III) (hereinafter sometimes referred to as “cyclic siloxane”) is preferable. [Chemical formula]

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

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

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

Chemical formula

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

[0134] As the siloxane compound, more specifically, cyclic siloxanes having two or more glycidyl groups in the molecule represented by the following formula can be mentioned. Further, as the siloxane compound, for example, commercially available products such as trade names "X-40-2670", "X-40-2701", "X-40-2728", "X-40-2738", "X-40-2740" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

[0135] [Chemical formula]

[0136] [Chemical formula]

[0137] The content of the monomer compound (B) in the varnish composition is not particularly limited as long as it does not inhibit the object of the present invention. When the mass of the varnish composition excluding the mass of the solvent (S) described later is 100 parts by mass, the content of the monomer compound (B) in the varnish composition is preferably 0.1 part by mass or more and 50 parts by mass or less, more preferably 0.5 part 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.

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

[0139] Specific examples of the photo radical polymerization initiator (C1) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(4-dimethylaminophenyl) ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, O-acetyl-1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone oxime, (9-ethyl-6-nitro-9H-carbazol-3-yl)[4-(2-methoxy-1-methylethoxy)-2-methylphenyl]methanone O-acetoxyoxime, 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-ethylhexyl benzoate, 4-dimethylamino-2-isoamyl benzoate, benzyl-β-methoxyethyl acetal, benzyl dimethyl ketal, 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, methyl o-benzoylbenzoate, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 1-chloro-4-propoxythioxanthone, thioxanthene, 2-chlorothioxanthene, 2,4-diethylthioxanthene, 2-methylthioxanthene, 2-isopropylthioxanthene, 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-Diphenylanthraquinone, azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)-imidazolyl dimer, benzophenone, 2-chlorobenzophenone, p,p'-bisdimethylaminobenzophenone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, 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, p-tert-butyldichloroacetophenone, α,α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, pentyl-4-dimethylaminobenzoate, 9-phenylacridine, 1,7-bis-(9-acridinyl)heptane, 1,5-bis-(9-acridinyl)pentane, 1,3-bis-(9-acridinyl)propane, p-methoxy triazine, 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)-4,6-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-methoxystyryl)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxystyryl)phenyl-s-triazine and the like can be mentioned. These photoinitiators can be used alone or in combination of two or more kinds.,

[0140] Typical examples of the photo cationic polymerization initiator (C2) include onium salts. Examples of the photo cationic polymerization initiator (C2) include oxonium salts, ammonium salts, phosphonium salts, sulfonium salts, and iodonium salts. Sulfonium salts and iodonium salts are preferred, and sulfonium salts are more preferred.,

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

[0142] The varnish composition contains an organic solvent (S). The type of the organic solvent (S) is not particularly limited as long as the polyimide resin (A) and other components are well dissolved., From the viewpoint of the good solubility of the polyimide resin (A), the organic solvent (S) preferably contains at least one 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. In the organic solvent (S), the content of these preferred organic solvents is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0143] The varnish composition may contain various additives other than the components described above, if necessary. Examples of the additives include colorants, dispersants, sensitizers, adhesion promoters, antioxidants, ultraviolet absorbers, anti-aggregation agents, defoaming agents, surfactants, and the like. Further, the varnish composition may contain various fillers or reinforcing materials, if necessary. The amount of use of each additive is not particularly limited as long as it does not inhibit the object of the present invention. For example, it may be appropriately adjusted within the range of 0.001% by mass or more and 60% by mass or less, preferably 0.05% by mass or more and 5% by mass or less, based on the mass of the solid content of the varnish composition. The amount of use of the filler or reinforcing material is not particularly limited as long as it does not inhibit the object of the present invention. The amount of use of the filler or reinforcing material is typically preferably 1% by mass or more and 300% by mass or less, more preferably 5% by mass or more and 200% by mass or more, still more preferably 10% by mass or more and 100% by mass or less, based on the mass of the polyamic acid (A).

[0144] ≪Method for producing polyimide film≫ After the varnish composition described above is applied onto a desired substrate to form a coating film, at least a part of the organic solvent (S) is removed from the coating film to form a polyimide film. That is, a coating step of applying the above-described varnish composition onto a substrate to form a coating film, and an organic solvent removing step of removing at least a part of the organic solvent (S) from the coating film. A polyimide film is produced by a method including

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

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

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

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

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

[0150] When the varnish composition contains a photoinitiator (C), after forming a coating film by the above method, exposure and development are performed on the coating film to obtain a patterned polyimide film. That is, a coating step of forming a coating film by applying a varnish composition containing a photoinitiator (C) onto a substrate; an organic solvent removal step of removing at least a part of the organic solvent (S) from the coating film; a patterning step of performing exposure and development on the coating film from which at least a part of the organic solvent (S) has been removed; A patterned polyimide film is manufactured by a method including these steps.

[0151] In the above method for manufacturing a patterned polyimide film, the application of the varnish composition and the heating of the coating film for removing the organic solvent (S) are carried out according to the above method.

[0152] The conditions for exposing the varnish composition are not particularly limited as long as curing proceeds well. The exposure is performed, for example, by irradiating active energy rays such as ultraviolet rays and excimer laser light. The dose of the energy rays to be irradiated is not particularly limited, but for example, 30 mJ / cm 2 or more and 5000 mJ / cm 2 or less can be mentioned. After exposure, the exposed coating film may be baked by the same method as the heating after application.

[0153] The developing method is not particularly limited, and for example, an immersion method, a spray method, etc. can be used. Specific examples of the developer include the organic solvent (S) that the varnish composition may contain.

[0154] After development, if necessary, rinsing with pure water or the like and baking are performed on the developed coating film to obtain a patterned polyimide film. As the baking conditions after development, for example, 150°C or higher and 280°C or lower are preferable, and 180°C or higher and 230°C or lower are more preferable. The baking time after development is, for example, preferably 5 minutes or longer and 12 hours or shorter, more preferably 10 minutes or longer and 6 hours or shorter, and particularly preferably 30 minutes or longer and 1 hour or longer.

Example

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

[0156] 〔Example 1〕 Into a three-necked flask, 15.57 g of 4,4'-(4-aminophenyloxy)biphenyl (hereinafter referred to as BPAB) as a diamine component, 6.43 g of 3,5-diaminobenzoic acid (hereinafter referred to as DABA), and 250 g of NMP were added. Next, the contents of the flask were stirred to dissolve BPAB and DABA in NMP. Then, 40 g of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (hereinafter referred to as BPADA) as a tetracarboxylic dianhydride component was added to the solution in the flask, and the reaction solution in the flask was stirred at room temperature for 24 hours. Then, 0.88 g of 5-norbornene-2,3-dicarboxylic anhydride as a terminal blocking agent was added to the reaction solution, and the reaction solution was stirred at room temperature for 4 hours to obtain a polyamic acid. In addition, the numerical value at the lower right of the parentheses in the following formula is the molar ratio (mol%) of each structural unit in the resin.

[0157] <Polyamic acid formation>

Chemical formula

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

[0159] <Imidization>

Chemical formula

[0160] Into a three-necked flask, the obtained polyimide resin having a carboxy 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 then the reaction solution was stirred at room temperature for 6 hours. The reaction solution after stirring was dropped into 2 kg of methanol to form a precipitate. The formed precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of methanol and then dried under reduced pressure at 50 °C to obtain a polyimide resin having a methacryloyl group at the side chain end and consisting of the structural units in the following formula. Regarding the obtained polyimide resin 1 1H-NMR measurement was performed. Imidization was confirmed by the disappearance of the peak corresponding to the amide bond, and it was confirmed that the theoretical amount of methacryloyl groups was introduced into the polyimide resin from the integral ratio of all aromatics and the integral ratio of double bonds.

[0161] <Introduction of methacryloyl group>

Chemical formula

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

Chemical Structure

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

Chemical Structure

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

Chemical Structure

[0165]

Chem.

[0166] 〔Example 5〕 Change 15.57 g of BPAB to 30.68 g of 2,2-bis[4-(4-aminophenyloxy)phenyl]-1,1,1,3,3,3-hexafluorophenylpropane (hereinafter referred to as HF-BPAA), change the amount of DABA used to 3.86 g, change the amount of 2-hydroxyethyl methacrylate used to 4.95 g, and change the amount of WSC-HCl used to 13.62 g. Otherwise, in the same manner as in Example 1, a polyimide resin having the structure of the following formula was synthesized. Regarding the obtained polyimide resin 1 Perform 1H-NMR measurement, confirm imidization by the disappearance of the peak corresponding to the amide bond, and confirm that the theoretical amount of methacryloyl groups was introduced into the polyimide resin from the integral ratio of all aromatic groups and the integral ratio of double bonds.

Chem.

[0167]

Chem.

[0168] 〔Example 6〕 Change 40 g of BPADA to 40 g of 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride (hereinafter referred to as 6FDA), change 15.57 g of BPAB to 35.94 g of HF-BPAA, change the usage amount of DABA to 4.52 g, change the usage amount of carbodiimidazole to 28.17 g, change the usage amount of 2-hydroxyethyl methacrylate to 5.80 g, and change the usage amount of WSC-HCl to 15.95 g. Otherwise, in the same manner as in Example 1, a polyimide resin having the structure of the following formula was synthesized.

Chemical formula

[0169]

Chemical formula

[0170] 〔Example 7〕 Change 40 g of BPADA to 40 g of 3,3’,4,4’-tetracarboxydiphenyl ether dianhydride (hereinafter referred to as ODPA), change 15.57 g of BPAB to 51.47 g of HF-BPAA, change the usage amount of DABA to 6.47 g, change the usage amount of carbodiimidazole to 28.17 g, change the usage amount of 2-hydroxyethyl methacrylate to 5.80 g, and change the usage amount of WSC-HCl to 15.95 g. Otherwise, in the same manner as in Example 1, a polyimide resin having the structure of the following formula was synthesized.

Chemical formula

[0171]

Chemical formula

[0172] 〔Example 8〕 Into a three-necked flask, 24.91 g of BPAB as a diamine component, 5.89 g of 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, and 250 g of NMP were added. Then, the contents of the flask were stirred to dissolve the diamine component in NMP. Thereafter, 40 g of BPADA was added to the solution in the flask, and the reaction solution in the flask was stirred at room temperature for 24 hours to produce polyamic acid.

[0173] <Polyamic acid production>

Chemical formula

[0174] 33 g of carbodiimidazole was added to the reaction solution containing polyamic acid, and the reaction solution was stirred at room temperature for 4 hours to convert the polyamic acid into a polyimide resin. The stirred reaction solution was dropped into 5 kg of water to form a precipitate. The formed 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 phenolic hydroxyl groups and consisting of the structural units in the following formula.

[0175] <Imidization>

Chemical formula

[0176] Into the three-necked flask, the obtained polyimide resin having phenolic hydroxyl groups, 5.30 g of methacrylic acid chloride, 4.50 g of triethylamine, and 300 g of NMP were added, and the reaction solution in the flask was stirred at room temperature for 6 hours. The stirred reaction solution was dropped into 2 kg of methanol to form a precipitate. The formed precipitate was collected by filtration. The collected precipitate was washed three times with 2 kg of methanol and then dried under reduced pressure at 50°C to obtain a polyimide resin having a methacryloyl group at the side chain end and consisting of the structural units in the following formula. Regarding the obtained polyimide resin 11H-NMR measurement was carried out, and imidization was confirmed by the disappearance of the peak corresponding to the amide bond. It was confirmed that the theoretical amount of methacryloyl groups was introduced into the polyimide resin from the integral ratio of all aromatics and the integral ratio of double bonds.

[0177] <Introduction of methacryloyl group>

Chemical formula

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

[0179]

Chemical formula

[0180] 〔Comparative Example 2〕 A photosensitive polyamide resin composed of the following structural units was obtained by the same method as in Synthesis Example 1 described in International Publication No. 2018 / 003726. The following polyamide resin generates a polyimide resin by ring closure accompanied by the elimination of 2-hydroxyethyl methacrylate by heating.

Chemical formula

[0181] 〔Examples 9 to 19, Comparative Example 3, or Comparative Example 4〕 100 parts by mass of the polyimide resin or polyamide resin of the type described in Table 1 was dissolved in NMP so that the concentration became 20% by mass. To the obtained solution, 5 parts by mass of Irgacure OXE01 (manufactured by BASF Japan Ltd.), which is 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.), which is a chain transfer agent, were added to obtain the photosensitive composition of each example. To the photosensitive compositions of Examples 12 to 14, photopolymerizable monomers of the type and amount described in Table 1 were further added. The photopolymerizable monomers described in Table 1 are as follows. M1: Dimethyloltricyclodecane diacrylate M2: Dipentaerythritol hexaacrylate

[0182] Using the obtained photosensitive composition, according to the following method, evaluation of the imidization rate during film formation, photosensitivity evaluation, and evaluation of dielectric properties by measurement of dielectric properties were performed. The results of the photosensitivity evaluation and the results of the dielectric property evaluation are shown in Table 1.

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

[0184] Note that the imidization rates of the polyimide resin films obtained by the above method using the NMP solutions of the polyimide resins obtained in Examples 9 to 19 and Comparative Example 3 were all 95% or more. Regarding the photosensitive composition of Comparative Example 4 containing the photosensitive polyamide resin obtained in Comparative Example 2, an imidization rate of 95% or more could not be achieved by exposure under the above conditions and heating at 180°C for 1 hour. Further, an imidization rate of 95% or more was achieved by heating at 350°C for 1 hour. 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 and not heated at 350°C was measured. In the FT-IR spectrum of the film heated at 350°C, the height H of the peak of the imide stretching vibration at a wavenumber of 1380 cm -1 and the height H of the aromatic peak 01 were used to obtain the ratio H 02 / H 01 of the two. 02 The value was determined. Next, in the FT-IR spectrum of the film not heated at 350°C, the height H of the peak of the imide stretching vibration at a wavenumber of 1380 cm -1 and the height H of the aromatic peak 11 were used to obtain the ratio H 12 / H 11 of the two. 12 The value was determined. The value of H 01 / H 02 and the value of H 11 / H 12 were used to measure the imidization rate according to the following formula. Imidization rate (%) = (H 11 / H 12 ) / (H 01 / H 02 ) × 100

[0185] <Photosensitivity evaluation> On a copper wafer, a coating film formed by spin-coating a photosensitive composition was baked at 80°C for 300 seconds. The rotation speed during spin-coating was adjusted so that the film thickness of the coating film after baking was 10 μm. The baked coating film was exposed through a negative mask for forming holes having a substantially square opening with a size of 50 μm × 50 μm, with an exposure amount ranging from 100 mJ / cm 2 to 4000 mJ / cm 2 at a focus of 0 μm. The exposed coating film was immersed in cyclopentanone for 60 seconds for development. The developed coating film was observed with a scanning electron microscope (SEM). When holes having a substantially square opening with a size of 50 μm × 50 μm could be formed, it was judged as ○, and in cases other than the ○ judgment, it was judged as ×.

[0186] <Dielectric property measurement> Except for changing the film thickness to 10 μm, a film obtained by the same method as the above-described film formation was used as a sample. The dielectric constant (ε) and dielectric tangent (tanδ) of the sample were measured by the method described in "Study on millimeter-wave complex dielectric constant evaluation of photosensitive insulating films by cylindrical cavity resonator method" (Kouhei Takahagi (University of Tsukuba), Kazuaki Ebisawa (Tokyo Ohka Kogyo Co., Ltd.), Yoshinori Furugami (University of Tsukuba), Takashi Shimizu (University of Tsukuba)), Transactions of the Institute of Electronics, Information and Communication Engineers, vol. 118, no. 506, MW2018-158, pp. 13-18, March 2019. Using a network analyzer HP8510C (manufactured by Keysight Technologies), the measurement was performed by the cavity resonator method under the conditions of room temperature 25°C, humidity 50%, frequency 36 GHz, and sample thickness 10 μm. When the dielectric constant value was less than 3.00, it was judged as ○, and when it was 3.00 or more, it was judged as ×. When the dielectric tangent value was less than 0.01, it was judged as ○, and when it was 0.01 or more, it was judged as ×.

[0187]

Table 1

[0188] According to Examples 9 to 11, it can be seen that a polyimide resin containing a structural unit of a specific structure represented by the aforementioned formula (A1a) and having a polymerizable group such as a methacryloyl group dissolves well in an organic solvent such as NMP, exhibits good photosensitivity, and provides a polyimide resin film excellent in dielectric properties. On the other hand, according to Comparative Example 3 and Comparative Example 4, it can be seen that even if a polyimide resin has a polymerizable group but does not contain a structural unit of a specific structure represented by the aforementioned formula (A1), it provides a polyimide resin film inferior in dielectric properties.

Claims

A varnish composition comprising a polyimide resin (A) and an organic solvent (S), wherein the polyimide resin (A) has a molecular chain containing a structural unit represented by the following formula (A1a): 【Chemical 1】 (In formula (A1a), X １ is a divalent organic group, and Y １ is a tetravalent organic group. However, X １ does not include a divalent organic group having a polyorganosiloxane structure and a structure derived from a dimer diamine, and Y １ does not include a tetravalent organic group having a sulfonyl group (—SO ２ —).) and has a partial structure represented by Said X １ At least one of the divalent organic group as said, and said Y １ At least one of the tetravalent organic group as said is represented by the following formula (a1): 【Chemical 2】 (In formula (a1), R ａ１ and R ａ２ are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, n1 and n2 are each independently an integer of 0 or more and 4 or less, R ａ３ and R ａ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R ａ３ and R ａ４ may be bonded to each other to form a ring.) or or has a molecular chain containing a structural unit represented by the formula (A1a) and a molecular chain containing a structural unit represented by the following formula (A1e): [Chemical Formula 3] (In formula (A1e), X ４ is a divalent organic group having no partial structure represented by the said formula (a1), and Y ２ is a tetravalent organic group having no partial structure represented by the said formula (a1). However, X ４ does not include a divalent organic group having a polyorganosiloxane structure and a structure derived from a dimer diamine, and Y ２ does not include a tetravalent organic group having a sulfonyl group (—SO ２ —).) wherein the structural unit represented by the formula (A1e) does not have the partial structure represented by the formula (a1), and the molecular chain contains a radical polymerizable group, a varnish composition for pattern formation.

2. As the structural unit represented by the formula (A1a), the molecular chain has one or more selected from the group consisting of a structural unit represented by the following formula (A1b): a structural unit represented by the following formula (A1c): and a structural unit represented by the following formula (A1d): [Chemical Formula 4] (In formula (A1b), X ２ and X ３ are each independently a divalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom, and Y ２ is a tetravalent organic group having no partial structure represented by the said formula (a1), and R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as these in formula (a1).) The varnish composition for pattern formation according to claim 1. [Chemical Formula 5] (In formula (A1c), X ４ is a divalent organic group that does not have the partial structure represented by the said formula (a1), Y ３ and Y ４ are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom, R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as these in formula (a1).)

3. [Chemical Formula 6] (In formula (A1d), X ５ and X ６ are each independently a divalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. Y ５ and Y ６ are each independently a trivalent aromatic hydrocarbon group which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. R ａ１ , R ａ２ , R ａ３ , R ａ４ , n1, and n2 are the same as these in formula (a1).)

4. The varnish composition for pattern formation according to any one of claims 1 to 3, having a (meth)acryloyl group-containing group as the radical polymerizable group. The polyimide resin contains a structural unit represented by the formula (A1c), and the X ４ has the radically polymerizable group. The varnish composition for pattern formation according to claim 2.

5. Further comprising a monomer compound (B), The varnish composition for pattern formation according to any one of claims 1 to 4, wherein the monomer compound (B) is a monomer compound having an ethylenically unsaturated double bond.

6. The varnish composition for pattern formation according to claim 5, wherein the monomer compound (B) is a polyfunctional monomer compound.

7. The content of the monomer compound (B) is 0.1 part by mass or more and 50 parts by mass or less when the mass of the varnish composition excluding the mass of the organic solvent (S) is 100 parts by mass. The varnish composition for pattern formation according to claim 5 or 6.

8. The ratio of the mass of the polyimide resin (A) to the mass of the varnish composition is 5% by mass or more and 50% by mass or less. The varnish composition for pattern formation according to any one of claims 1 to 7.

9. At 20 ° C., 80% by mass or more of the polyimide resin (A) is dissolved in the organic solvent (S). The varnish composition for pattern formation according to any one of claims 1 to 8.

10. ​ ​ The pattern-forming varnish composition according to any one of claims 1 to 9, wherein 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.

11. The pattern-forming varnish composition according to any one of claims 1 to 10, which contains a photoinitiator (C).

12. A coating step of coating the substrate with the pattern-forming varnish composition according to any one of claims 1 to 11 to form a coating film, An organic solvent removal step of removing at least a part of the organic solvent (S) from the coating film, A method for producing a polyimide film, comprising:

13. A coating step of coating the substrate with the pattern-forming varnish composition according to claim 11 to form a coating film, An organic solvent removal step of removing at least a part of the organic solvent (S) from the coating film, A patterning step of performing exposure and development on the coating film from which at least a part of the organic solvent (S) has been removed, A method for producing a patterned polyimide film, comprising:

Images