Thermosetting resin composition, cured product, and flexible printed substrate

Abstract

One embodiment of the present invention pertains to a thermosetting resin composition containing: a resin having at least one group selected from the group consisting of acid anhydride groups and a carboxy group; and a trifunctional amine-type epoxy resin.

Description

Thermosetting resin composition, cured product, and flexible printed circuit board

[0001] The present disclosure relates to a thermosetting resin composition, a set for a thermosetting resin composition, a cured product, a film, a flexible printed circuit board, and an electronic component.

[0002] Flexible printed circuit boards are widely used in electronic devices such as various displays and smartphones. Flexible printed circuit boards generally have a protective film for ensuring electrical insulation between wirings and preventing corrosion of the wiring. The protective film can be formed using, for example, a thermosetting resin composition. The protective film is required to have properties suitable for its intended use.

[0003] For example, Patent Document 1 describes a thermosetting resin composition containing (A) a resin having at least one acid anhydride group and / or a carboxy group, (B) an inorganic filler containing hydrotalcite and silica, and (C) an epoxy resin.

[0004] JP 2009-275114 A

[0005] Depending on the environment in which electronic devices such as TV (television) panels and PC (personal computer) displays are used, dirt may adhere to the surfaces, and end users may use cleaning agents to remove the dirt. If the cleaning agent accidentally seeps into the display and reaches the flexible printed circuit board, the cleaning agent may cause a short circuit between the wiring if the protective film on the wiring does not provide sufficient protection.

[0006] Therefore, the present disclosure provides a thermosetting resin composition that can produce flexible printed circuit boards and electronic components that have excellent resistance to cleaning agents. The present disclosure also provides a set including a first part and a second part for producing the thermosetting resin composition, as well as a cured product and a film obtained using the thermosetting resin composition or the set. The present disclosure also provides a flexible printed circuit board and electronic components that have excellent resistance to cleaning agents.

[0007] Embodiments of the present invention are listed below. The present invention is not limited to the following embodiments. One embodiment relates to a thermosetting resin composition containing a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group, and a trifunctional amine-type epoxy resin. Another embodiment relates to a set for a thermosetting resin composition, which is used to obtain the thermosetting resin composition and includes a first part containing the resin and a second part containing the trifunctional amine-type epoxy resin. Another embodiment relates to a cured product obtained using the thermosetting resin composition or the set for a thermosetting resin composition. Another embodiment relates to a film obtained using the thermosetting resin composition or the set for a thermosetting resin composition. Another embodiment relates to a flexible printed circuit board obtained using the thermosetting resin composition or the set for a thermosetting resin composition. Another embodiment relates to an electronic component obtained using the thermosetting resin composition or the set for a thermosetting resin composition.

[0008] According to the present disclosure, there is provided a thermosetting resin composition that can provide flexible printed circuit boards and electronic components having excellent resistance to cleaning agents. The present disclosure also provides a set including a first part and a second part for obtaining the thermosetting resin composition, as well as a cured product and a film obtained using the thermosetting resin composition or the set. Furthermore, the present disclosure also provides flexible printed circuit boards and electronic components having excellent resistance to cleaning agents.

[0009] Fig. 1 is a schematic front view of a test piece for evaluating detergent resistance prepared in the examples. Fig. 2 is a schematic front view showing an enlarged view of the wiring portion of the test piece shown in Fig. 1. Fig. 3 is a schematic front view showing the test piece in contact with a detergent in the examples. Fig. 4 is a schematic perspective view showing the test piece in contact with a detergent in the examples.

[0010] The following describes embodiments of the present invention. The present invention is not limited to the following embodiments. The following embodiments can be implemented alone or in combination. Combinations of multiple embodiments are also included in the present invention.

[0011] In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range. The upper or lower limit value of a numerical range described in this disclosure may be replaced with a value shown in the examples. A numerical value may be selected from the upper and lower limit values ​​described in stages in this disclosure to form a staged numerical range. The upper and lower limit values ​​described in this disclosure may be replaced with values ​​shown in the examples. In this disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In this disclosure, each structure in a resin or polymer may contain multiple corresponding structures. When multiple structures corresponding to each structure are present in the resin or polymer, the content or amount of each structure means the total content or amount of the multiple structures present in the resin or polymer, unless otherwise specified. In the present disclosure, the term "layer" includes continuous and discontinuous layers. The thickness of a "layer" may be uniform or non-uniform. The outer edges of a "layer" in the planar direction and the outer edges in the thickness direction may be clear or unclear. The same applies to a "film." When embodiments are described in the present disclosure with reference to drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of components in each drawing are conceptual, and the relative size relationships between components are not limited to the relationships shown in the drawings.

[0012] <Thermosetting Resin Composition> In some embodiments, the thermosetting resin composition contains a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group, and a trifunctional amine-type epoxy resin. In the present disclosure, the resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group may be referred to as "resin A," and the at least one group selected from the group consisting of an acid anhydride group and a carboxy group may be referred to as "acid anhydride group or carboxy group." In the present disclosure, the acid anhydride group may be a carboxylic acid anhydride group. The thermosetting resin composition may further contain optional components such as a tetrafunctional amine-type epoxy resin, an epoxy resin other than the amine-type epoxy resin, an organic solvent, and additives.

[0013] [Resin Having Acid Anhydride Group or Carboxy Group] Examples of resins having an acid anhydride group or a carboxy group include phenolic resins, acrylic resins, polyurethanes, polybutadienes, hydrated polybutadienes, polyesters, polycarbonates, polyethers, polysulfones, polytetrafluororesins, polysilicones, melamine resins, polyamides, polyamideimides, polyimides, and the like, which have an acid anhydride group or a carboxy group in the main chain, side chain, or both the main chain and the side chain. The thermosetting resin composition may contain one type of resin having an acid anhydride group or a carboxy group alone, or two or more types in combination.

[0014] In some embodiments, the thermosetting resin composition contains a polyamideimide having an acid anhydride group or a carboxy group. Polyamideimide is a resin containing an amide bond (amide group) and an imide bond (imide group). When the thermosetting resin composition contains a polyamideimide having an acid anhydride group or a carboxy group, a cured product having excellent insulating properties and heat resistance and excellent resistance to cleaning agents can be obtained. In the present disclosure, resistance to cleaning agents may be referred to as "detergent resistance." The polyamideimide may have an acid anhydride group or a carboxy group at the end of the molecular chain.

[0015] In some embodiments, the polyamideimide may contain a urethane bond. A polyamideimide containing a urethane bond can be synthesized, for example, by reacting a polyol with a polyisocyanate to obtain a polyisocyanate having a urethane bond (sometimes referred to as "polyisocyanate A" in the present disclosure), and then reacting this with a tricarboxylic acid compound. The polyamideimide may contain a polyurethane structure in its molecule to improve flexibility. The polyol may be used alone or in combination of two or more. The polyisocyanate may be used alone or in combination of two or more.

[0016] (Polyol) Examples of polyols include alicyclic diols, aliphatic diols, and diol compounds represented by the following formula (P1). The diol may contain an alicyclic diol from the viewpoint of obtaining a cured product having excellent flexibility while maintaining high insulation reliability. The diol may contain an aliphatic diol from the viewpoint of obtaining a cured product in which warpage is sufficiently suppressed and which has excellent flexibility. In the present disclosure, the property of suppressing warpage may be referred to as "low warpage."

[0017] The alicyclic diol is a diol having a divalent organic group having an alicyclic hydrocarbon group, and the number of carbon atoms in the alicyclic hydrocarbon group is, for example, 5 to 10. Examples of the alicyclic diol include 5-membered ring diols such as 1,2-cyclopentane dimethanol, 1,3-cyclopentane dimethanol, and bis(hydroxymethyl)tricyclo[5.2.1.0]decane; and 6-membered ring diols such as 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 2,2-bis(4-hydroxycyclohexyl)-propane.

[0018] The aliphatic diol is a diol having a divalent organic group having an aliphatic hydrocarbon group (however, the divalent organic group does not have an alicyclic hydrocarbon group), and the number of carbon atoms in the aliphatic hydrocarbon group is, for example, 1 to 18. The aliphatic hydrocarbon group may be linear or branched. Examples of the aliphatic diol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, and 1,6-hexane glycol.

[0019] The diol may be, for example, a diol compound represented by the following formula (P1).

[0020]

[0021] In the formula, R ｐ represents a divalent organic group having an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or a divalent organic group having an aliphatic hydrocarbon group having 1 to 18 carbon atoms (however, the divalent organic group does not have an alicyclic hydrocarbon group), and n represents a number from 1 to 30. ｐ may be the same or different. The divalent organic group having an aliphatic hydrocarbon group is, for example, a linear or branched alkylene group. n is the average number of units.

[0022] The diol compound represented by formula (P1) is, for example, R ｐ The diol may be a copolymerized carbonate diol containing a structure derived from a diol having a divalent organic group having an alicyclic hydrocarbon group and a structure derived from a diol having a divalent organic group having an aliphatic hydrocarbon group.

[0023] In this copolymerized carbonate diol, the molar ratio of the structure derived from a diol having a divalent organic group having an aliphatic hydrocarbon group to the structure derived from a diol having a divalent organic group having an alicyclic hydrocarbon group is, for example, 0.1 or more, 0.3 or more, or 0.5 or more, from the viewpoint of obtaining excellent insulation reliability and folding endurance. From the same viewpoint, the molar ratio is, for example, 2 or less, 1 or less, or 0.5 or less. The molar ratio is, for example, 0.1 to 2, 0.3 to 1, 0.1 to 0.5, or 0.5 to 1. n is, for example, 10 to 30, 15 to 28, or 20 to 25.

[0024] For example, the diol having a divalent organic group having an alicyclic hydrocarbon group may be 1,4-cyclohexanedimethanol, and the diol having a divalent organic group having an aliphatic hydrocarbon group may be 1,6-hexanediol. In other words, the diol compound represented by formula (P1) may be a copolymerized carbonate diol, which is a copolymer using 1,4-cyclohexanedimethanol and 1,6-hexanediol. A copolymeric carbonate diol in which the molar ratio of 1,4-cyclohexanedimethanol to 1,6-hexanediol is 3 / 1 is commercially available from UBE Corporation as "UM-90 (3 / 1)"; a copolymeric carbonate diol in which the molar ratio of 1,4-cyclohexanedimethanol to 1,6-hexanediol is 1 / 1 is commercially available from UBE Corporation as "UM-90 (1 / 1)"; and a copolymeric carbonate diol in which the molar ratio of 1,4-cyclohexanedimethanol to 1,6-hexanediol is 1 / 3 is commercially available from UBE Corporation as "UM-90 (1 / 3)".

[0025] The diol compound represented by formula (P1) is, for example, R ｐ In the carbonate diol, n is, for example, 2 to 10, 3 to 8, or 4 to 6.

[0026] For example, the diol having a divalent organic group having an aliphatic hydrocarbon group may be 1,6-hexanediol. In other words, the diol compound represented by formula (P1) may be a carbonate diol, which is a polymer using 1,6-hexanediol. ｐis a divalent organic group having an aliphatic hydrocarbon group, examples of the diol compound include α,ω-poly(hexamethylene carbonate)diol and α,ω-poly(3-methyl-pentamethylene carbonate)diol. Commercially available products include PLACCEL CD-205, 205PL, 205HL, 210, 210PL, 210HL, 220, 220PL, and 220HL manufactured by Daicel Corporation; PCDL T-5651, T-5652, T-6001, T-6002, G-3452, and PCDX-55 manufactured by Asahi Kasei Corporation; and UH-50, 100, 200, 300, UHC-50-100, and 200 manufactured by UBE Corporation.

[0027] The number average molecular weight of the diol compound represented by formula (P1) is, for example, 300 or more, 500 or more, or 700 or more. The number average molecular weight is, for example, 4,000 or less, 3,000 or less, or 2,000 or less. The number average molecular weight is, for example, 300 to 4,000, 500 to 3,000, or 700 to 2,000. In the present disclosure, the number average molecular weight is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene. Details of the method for measuring the number average molecular weight are provided in the Examples.

[0028] In the polyamideimide, the molar ratio of the structure derived from a diol having a divalent organic group having an aliphatic hydrocarbon group to the structure derived from a diol having a divalent organic group having an alicyclic hydrocarbon group is, for example, 0.1 or more, 0.3 or more, or 0.4 or more, from the viewpoint of obtaining excellent insulation reliability and folding endurance. From the same viewpoint, the molar ratio is, for example, 2 or less, 1 or less, or 0.6 or less. The molar ratio is, for example, 0.1 to 2, 0.3 to 1, or 0.4 to 0.6.

[0029] From the viewpoint of easily imparting properties such as an improved glass transition temperature and an improved elastic modulus and thus obtaining excellent insulation reliability, the ratio of the structure derived from the alicyclic diol may be, for example, 0.1 mass% or more, 3 mass% or more, or 5 mass% or more, based on the mass of the polyamideimide. From the viewpoint of easily suppressing improvement in the crystallinity of the polyamideimide and easily obtaining good solubility in solvents, the ratio of the structure derived from the alicyclic diol may be, for example, 30 mass% or less, 25 mass% or less, or 20 mass% or less, based on the mass of the polyamideimide. The ratio of the structure derived from the alicyclic diol may be, for example, 0.1 to 30 mass%, 3 to 25 mass%, or 5 to 20 mass%, based on the mass of the polyamideimide. In calculating the ratio, the "structure derived from the alicyclic diol" refers to the portion remaining after removing two hydroxy groups from the alicyclic diol. For example, when the alicyclic diol is 1,4-cyclohexanedimethanol, the portion obtained by removing the two hydroxy groups from 1,4-cyclohexanedimethanol is considered to be the "structure derived from the alicyclic diol" and the ratio is calculated.

[0030] The diol may be, for example, a polyether diol, a polyester diol, a polycaprolactone diol, a silicone diol, or the like.

[0031] As the polyol, a triol having three hydroxy groups can be used in combination with a diol, such as 1,2,3-propanetriol (glycerin) or 1,2,4-butanetriol.

[0032] (Polyisocyanate) Examples of polyisocyanates include diisocyanate compounds represented by the following formula (P3).

[0033]

[0034] In the formula, X represents a divalent organic group.

[0035] Examples of the divalent organic group represented by X in formula (P3) include alkylene groups having 1 to 20 carbon atoms; arylene groups such as phenylene groups and naphthylene groups which are unsubstituted or substituted with a lower alkyl group having 1 to 5 carbon atoms such as a methyl group, or a lower alkoxy group having 1 to 5 carbon atoms such as a methoxy group; lower alkylene groups having 1 to 5 carbon atoms, oxy groups (—O—), carbonyl groups (—CO—), or sulfonyl groups (—SO ２ and an organic group formed by bonding two of the arylene groups via a carbon atom (-) and two lower alkylene groups having 1 to 5 carbon atoms via the arylene group. The alkylene group may have, for example, 1 to 18 carbon atoms. The divalent organic group represented by X is selected from groups having an aromatic ring, such as a phenylene group, a xylylene group, a naphthylene group, a diphenylmethane-4,4'-diyl group, and a diphenylsulfone-4,4'-diyl group, and groups formed by hydrogenating any of these.

[0036] Examples of the diisocyanate compound represented by formula (P3) include diphenylmethane-2,4'-diisocyanate, "3,2'-, 3,3'-, 4,2'-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate," "3,2'-, 3,3'-, 4,2'-, 4,3'-, 5 , 2'-, 5,3'-, 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate," "3,2'-, 3,3'-, 4,2'-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate," diphenylmethane-4,4'-diisocyanate, diphenyl Examples of the aromatic isocyanates include diphenylmethane diisocyanate compounds such as diphenylmethane-3,3'-diisocyanate and diphenylmethane-3,4'-diisocyanate; diphenylether-4,4'-diisocyanate; benzophenone-4,4'-diisocyanate; diphenylsulfone-4,4'-diisocyanate; tolylene-2,4-diisocyanate (2,4-tolylene diisocyanate); tolylene-2,6-diisocyanate (2,6-tolylene diisocyanate); m-xylylene diisocyanate; p-xylylene diisocyanate; 1,5-naphthalene diisocyanate; and 4,4'-[2,2-bis(4-phenoxyphenyl)propane]diisocyanate.

[0037] Examples of the diisocyanate compound represented by formula (P3) include aliphatic or alicyclic isocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, lysine diisocyanate, and hydrogenated aromatic isocyanates.

[0038] In the diisocyanate compound represented by formula (P3), the isocyanate group may be stabilized with a blocking agent to prevent deterioration over time. Examples of the blocking agent include, but are not limited to, hydroxyacrylate, alcohols such as methanol, phenols, and oximes.

[0039] As the polyisocyanate, a tri- or higher functional polyisocyanate may be used together with the diisocyanate compound represented by formula (P3).

[0040] (Reaction Method, etc.) The reaction of the polyol with the polyisocyanate can be carried out by heat condensation in the presence of an organic solvent, such as a nitrogen-free polar solvent. The organic solvent can be used alone or in combination of two or more.

[0041] The non-nitrogen-containing polar solvent is selected from, for example, ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether; sulfur-containing solvents such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, and sulfolane; ester solvents such as γ-butyrolactone and cellosolve acetate; ketone solvents such as cyclohexanone and methyl ethyl ketone; and aromatic hydrocarbon solvents such as toluene and xylene.

[0042] A solvent capable of dissolving the resulting resin can be selected and used. After synthesis, a solvent suitable for the thermosetting resin composition can be selected and used as is. The solvent may be γ-butyrolactone, which has a high boiling point, allows efficient reaction in a homogeneous system, and is suitable for printing operations when forming a protective film on a flexible wiring board or the like.

[0043] From the viewpoint of suppressing an increase in viscosity during the reaction and satisfactorily synthesizing polyisocyanate A, the amount of solvent used is, for example, 0.8 times (mass ratio) or more based on the total mass of the raw materials used in the synthesis of polyisocyanate A. From the viewpoint of suppressing a decrease in the reaction rate, the amount of solvent used is, for example, 5.0 times (mass ratio) or less.

[0044] The reaction temperature is, for example, 70° C. or higher, 75° C. or higher, or 80° C. or higher, from the viewpoint of preventing the reaction from taking a long time. The reaction temperature is, for example, 210° C. or lower, 190° C. or lower, or 180° C. or lower, from the viewpoint of preventing gelation during the reaction. The reaction time can be appropriately selected depending on the capacity of the reaction vessel, the reaction conditions to be adopted, etc.

[0045] If necessary, the reaction may be carried out in the presence of a catalyst such as a tertiary amine, an alkali metal, an alkaline earth metal, tin, zinc, titanium, cobalt, or other metal or semimetal compound.

[0046] The mixing ratio when reacting the polyol and the polyisocyanate may be adjusted as appropriate, taking into consideration, for example, the number average molecular weight of the polyisocyanate A to be produced and the fact that the polyisocyanate A to be produced has an isocyanate group at its terminal.

[0047] In order to synthesize polyisocyanate A having an isocyanate group at its terminal, the blending ratio of polyol and polyisocyanate can be adjusted so that the ratio of the number of isocyanate groups to the number of hydroxyl groups (number of isocyanate groups / number of hydroxyl groups) is, for example, 1.01 or more and 2.0 or less.

[0048] Polyisocyanate A is a compound containing a urethane bond, and includes, for example, a structure represented by the following formula (P2).

[0049]

[0050] In the formula, R ｐ represents a divalent organic group having an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or a divalent organic group having an aliphatic hydrocarbon group having 1 to 18 carbon atoms (provided that the divalent organic group does not have an alicyclic hydrocarbon group), X represents a divalent organic group, and n represents a number from 1 to 30. ｐ may be the same or different. * indicates the bonding position to other structures. ｐ and X are explained as R in formula (P2) ｐ and X.

[0051] The number average molecular weight of polyisocyanate A is, for example, 500 or more, 1,000 or more, or 1,500 or more. The number average molecular weight of polyisocyanate A is, for example, 30,000 or less, 25,000 or less, or 20,000 or less. The number average molecular weight of polyisocyanate A is, for example, 500 to 30,000, 1,000 to 25,000, or 1,500 to 20,000.

[0052] (Tricarboxylic acid compound) The tricarboxylic acid compound may be a trivalent polycarboxylic acid having an acid anhydride group or a derivative thereof. The derivative is, for example, an ester. Examples of the tricarboxylic acid compound include compounds represented by the following formula (P4) or (P5).

[0053]

[0054] In formula (P4), R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group.

[0055]

[0056] In formula (P5), R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group; Y represents —CH ２ -, -CO-, -SO ２ It represents - or -O-.

[0057] Specific examples of the tricarboxylic acid compound include trimellitic anhydride, benzenetricarboxylic anhydride, naphthalenetricarboxylic anhydride, 3,4,4'-benzophenonetricarboxylic anhydride, 3,4,4'-biphenylethertricarboxylic anhydride, 3,4,4'-biphenyltricarboxylic anhydride, 2,3,2'-biphenyltricarboxylic anhydride, 3,4,4'-biphenylmethanetricarboxylic anhydride, and 3,4,4'-biphenylsulfonetricarboxylic anhydride.

[0058] In addition to the tricarboxylic acid compound, a dicarboxylic acid compound such as a divalent polycarboxylic acid or a derivative thereof, or a tetracarboxylic acid compound such as a tetravalent polycarboxylic acid or a derivative thereof may be used.

[0059] (Reaction Method, etc.) The above-mentioned organic solvent can be used for the reaction between the polyisocyanate A and the tricarboxylic acid compound. The solvent used for the reaction may be, for example, the same organic solvent as that used for the reaction between the polyol and the polyisocyanate.

[0060] From the viewpoint of suppressing an increase in viscosity during the solvent reaction and smoothly synthesizing polyamideimide, the amount of solvent used is, for example, 0.8 times (mass ratio) or more based on the total mass of the raw materials used in the synthesis of polyamideimide. From the viewpoint of suppressing a decrease in the reaction rate, the amount of solvent used is, for example, 5.0 times (mass ratio) or less.

[0061] The reaction temperature is, for example, 70° C. or higher, 75° C. or higher, or 80° C. or higher, from the viewpoint of preventing the reaction from taking a long time. The reaction temperature is, for example, 210° C. or lower, 190° C. or lower, or 180° C. or lower, from the viewpoint of preventing gelation during the reaction. The reaction time can be appropriately selected depending on the capacity of the reaction vessel, the reaction conditions to be adopted, etc.

[0062] Polyamideimide may be obtained by reacting polyisocyanate A with a tricarboxylic acid compound together with another polyisocyanate (sometimes referred to as "polyisocyanate B" in the present disclosure). The polyisocyanate B is not particularly limited as long as it is an isocyanate other than polyisocyanate A, and examples thereof include a diisocyanate compound represented by formula (P3) and a trivalent or higher polyisocyanate. Polyisocyanate A and polyisocyanate B may each be used alone or in combination of two or more.

[0063] When polyisocyanate B is used in combination, the aromatic polyisocyanate may account for 50 to 100% by mass based on the total mass of polyisocyanate B. From the viewpoint of a balance between solubility, mechanical properties, cost, and the like, the aromatic polyisocyanate includes, for example, at least one selected from 4,4'-diphenylmethane diisocyanate and tolylene diisocyanate.

[0064] When polyisocyanate B is used in combination, the molar ratio of polyisocyanate A / polyisocyanate B is, for example, 0.1 / 0.9 to 0.9 / 0.1, 0.2 / 0.8 to 0.8 / 0.2, or 0.3 / 0.7 to 0.7 / 0.3. When the molar ratio is within this range, good adhesion between the cured product and an adherend such as a wired substrate is likely to be obtained.

[0065] An amine compound can also be used in combination with polyisocyanate A. Examples of the amine compound include a compound in which the isocyanate group in the diisocyanate compound represented by formula (P3) is converted into an amino group. The conversion of the isocyanate group into the amino group can be carried out by a known method.

[0066] In the reaction of polyisocyanate A with a tricarboxylic acid compound, from the viewpoint of increasing the number average molecular weight of the polyamideimide, the ratio of the total number of acid anhydride groups and carboxy groups in the acid anhydride or carboxylic acid used to the total number of isocyanate groups in the isocyanate used (total number of acid anhydride groups and carboxy groups / total number of isocyanate groups) is, for example, 0.6 or more, 0.7 or more, or 0.8 or more. From the same viewpoint, the ratio of the total number of carboxy groups to acid anhydride groups is, for example, 1.4 or less, 1.3 or less, or 1.2 or less. The ratio of the total number of carboxy groups to acid anhydride groups is, for example, 0.6 to 1.4, 0.7 to 1.3, or 0.8 to 1.2.

[0067] The number average molecular weight of the polyamideimide is, for example, 5,000 or more, 6,000 or more, or 7,000 or more from the viewpoint of preventing a decrease in weather resistance or detergent resistance. The number average molecular weight is, for example, 65,000 or less, 60,000 or less, 50,000 or less, or 25,000 or less from the viewpoint of good solubility in solvents and resistance to insolubilization during synthesis. The number average molecular weight of the polyamideimide is, for example, 5,000 to 60,000, 6,000 to 50,000, or 7,000 to 25,000.

[0068] The weight-average molecular weight of the polyamideimide is, for example, 10,000 or more, 20,000 or more, or 30,000 or more from the viewpoint of preventing a decrease in weather resistance or solvent resistance. The number-average molecular weight is, for example, 65,000 or less, 60,000 or less, or 50,000 or less from the viewpoint of good solubility in solvents and resistance to insolubilization during synthesis. The weight-average molecular weight of the polyamideimide is, for example, 10,000 to 65,000, 20,000 to 60,000, or 30,000 to 50,000.

[0069] In the present disclosure, the number average molecular weight and weight average molecular weight are values ​​measured by gel permeation chromatography (GPC) and converted using a calibration curve of standard polystyrene. Details of the method for measuring the number average molecular weight and weight average molecular weight are shown in the Examples.

[0070] The acid value of the polyamideimide is, for example, 5 mgKOH / g or more, 7 mgKOH / g or more, or 10 mgKOH / g or more from the viewpoint of sufficient curing and obtaining good weather resistance, flex resistance, etc. The acid value of the polyamideimide is, for example, 30 mgKOH / g or less, 20 mgKOH / g or less, or 15 mgKOH / g or less from the viewpoint of obtaining good low warpage properties, thermosetting properties, and insulation reliability. The acid value of the polyamideimide is, for example, 5 to 30 mgKOH / g, 7 to 20 mgKOH / g, or 10 to 15 mgKOH / g. The acid value can be measured by neutralization titration. Details of the acid value measurement method are shown in the Examples.

[0071] The polyamideimide obtained by the above production method can have, for example, a carboxy group or an acid anhydride group at the end of the molecular chain. When the polyamideimide has a urethane bond and a carboxy group or an acid anhydride group at the end of the molecular chain, flexibility and insulation reliability can be improved.

[0072] Resin A contained in the thermosetting resin composition is not limited to polyamideimide having an acid anhydride group or a carboxy group. In some embodiments, the thermosetting resin composition contains polyurethane having an acid anhydride group or a carboxy group. The polyurethane may contain an ester bond in the molecule in order to improve flexibility. The polyurethane may contain a fluorene structure or a cardo structure. In some embodiments, the thermosetting resin composition contains polyimide having an acid anhydride group or a carboxy group. The polyimide may contain a carbonate structure in the molecule in order to improve flexibility. The polyimide may contain a fluorene structure or a cardo structure.

[0073] [Epoxy Resin] The thermosetting resin composition contains a trifunctional amine-type epoxy resin. The thermosetting resin composition may further contain a tetrafunctional amine-type epoxy resin. The thermosetting resin composition may further contain an epoxy resin other than the amine-type epoxy resin (sometimes referred to as a "non-amine-type epoxy resin" in the present disclosure). In the present disclosure, the trifunctional amine-type epoxy resin is a compound containing a secondary amine structure, a tertiary amine structure, or both in the molecule and having three epoxy groups, and the tetrafunctional amine-type epoxy resin is a compound containing a secondary amine structure, a tertiary amine structure, or both in the molecule and having four epoxy groups. The non-amine-type epoxy resin is a compound containing neither a secondary amine structure nor a tertiary amine structure in the molecule and having one or more epoxy groups. The trifunctional amine-type epoxy resin, the tetrafunctional amine-type epoxy resin, and the non-amine-type epoxy resin may each be contained alone or in combination of two or more in the thermosetting resin composition.

[0074] (Trifunctional amine-type epoxy resin) The trifunctional amine-type epoxy resin may have, for example, a monoglycidylamino group, a diglycidylamino group, or both of them. The trifunctional amine-type epoxy resin may further have a glycidyloxy group. The trifunctional amine-type epoxy resin includes, for example, an epoxy resin represented by the following formula (E1).

[0075] (In the formula, R １ represents a divalent organic group.

[0076] R １ Examples of R include the groups exemplified in the description of X in the diisocyanate compound represented by formula (P3) above. １ may be, for example, an arylene group such as a phenylene group or a naphthylene group which is unsubstituted or substituted with a lower alkyl group having 1 to 5 carbon atoms such as a methyl group or a lower alkoxy group having 1 to 5 carbon atoms such as a methoxy group; may be an unsubstituted phenylene group or a phenylene group which is substituted with a lower alkyl group having 1 to 5 carbon atoms such as a methyl group; or may be an unsubstituted phenylene group or a methylphenylene group.

[0077] By including a trifunctional amine-type epoxy resin in a thermosetting resin composition, flexible printed circuit boards and electronic components with excellent detergent resistance can be obtained. The reason for this is presumed to be, for example, as follows. However, the present invention is not limited to the following. When a thermosetting resin composition includes a trifunctional amine-type epoxy resin, adhesion between a cured product such as a protective film and a protected object such as a wired substrate is improved. In particular, when the protected object includes a film containing an imide bond, an amide bond, or both an imide bond and an amide bond, such as a polyimide film, a polyamideimide film, or a polyamide film, it is believed that intermolecular interactions between similar moieties with high polarity between the amine structure and the imide or amide bond contained in the film are enhanced, further improving adhesion. Furthermore, by including a trifunctional amine-type epoxy resin in a thermosetting resin composition, it is likely that a film with reduced warping can be obtained. The greater the number of epoxy groups per epoxy resin molecule, the greater the density of the epoxy resin as a crosslinking point, making the cured product such as a protective film more likely to warp. It is believed that a smaller number of epoxy groups per epoxy resin molecule leads to less density, suppresses shrinkage, and reduces warping of the cured product. On the other hand, if the amine-type epoxy resin has two or fewer functional groups, it is impossible to introduce a network structure due to the epoxy resin into the cured product. Trifunctional amine-type epoxy resins can introduce a network structure into the cured product and easily prevent it from becoming dense. For these reasons, it is believed that penetration of the cleaner into the interface between the cured product and the object to be protected is suppressed, preventing short circuits caused by the cleaner between wiring and short circuits caused by migration due to metal deposition.

[0078] The epoxy equivalent of the trifunctional amine-type epoxy resin is, for example, 70 to 120 g / eq, 80 to 115 g / eq, or 90 to 110 g / eq. When the epoxy equivalent is 120 g / eq or less, the number of epoxy groups per mass is sufficient, tending to improve adhesion to the object to be protected. In particular, when the trifunctional amine-type epoxy resin has a monoglycidylamino group, a diglycidylamino group, or both, the effect of improving adhesion due to the amine structure is also likely to be obtained. When the epoxy equivalent is 70 g / eq or more, it tends to be easier to prevent crosslinking points from becoming dense. The epoxy equivalent can be measured, for example, according to JIS K7236:2001.

[0079] Commercially available trifunctional amine-type epoxy resins include, for example, "EP-3950E," "EP-3950S," and "EP-3950L" manufactured by ADEKA Corporation; "SUMIEPOXY ELM-100" and "SUMIEPOXY ELM-100H" manufactured by Sumitomo Chemical Co., Ltd.; and "jER630" and "jER630LSD" manufactured by Mitsubishi Chemical Corporation.

[0080] The content of the trifunctional amine-type epoxy resin is, for example, 1 to 16 mass%, 2 to 14 mass%, 3 to 12 mass%, or 3 to 10 mass%, based on the mass of Resin A. When the content is within the above range, better detergent resistance is likely to be obtained. From the viewpoint of obtaining particularly excellent detergent resistance, the content of the trifunctional amine-type epoxy resin may be 5 to 16 mass%, 7 to 12 mass%, or 8 to 10 mass%.

[0081] (Tetrafunctional amine-type epoxy resin) The tetrafunctional amine-type epoxy resin may have, for example, a monoglycidylamino group, a diglycidylamino group, or both. The tetrafunctional amine-type epoxy resin may further have a glycidyloxy group. The tetrafunctional amine-type epoxy resin includes, for example, an epoxy resin represented by the following formula (E2).

[0082] (In the formula, R ２ represents a divalent organic group.

[0083] R ２Examples of R include the groups exemplified in the description of X in the diisocyanate compound represented by formula (P3) above. ２ is, for example, an alkylene group having 1 to 20 carbon atoms; an arylene group such as a phenylene group or a naphthylene group which is unsubstituted or substituted with a lower alkyl group having 1 to 5 carbon atoms such as a methyl group, or a lower alkoxy group having 1 to 5 carbon atoms such as a methoxy group; or a lower alkylene group having 1 to 5 carbon atoms, an oxy group (—O—), a carbonyl group (—CO—), or a sulfonyl group (—SO ２ The alkylene group having 1 to 20 carbon atoms may be a linear, branched, or cyclic alkylene group, may be a cyclic alkylene group, or may be a cyclohexylene group. The arylene group may be an unsubstituted arylene group or an unsubstituted phenylene group. The organic group may be an organic group having two phenylene groups bonded via a lower alkylene group having 1 to 5 carbon atoms, and may be a diphenylmethanediyl group (*-Ph-CH ２ -Ph-* (Ph is a phenylene group).

[0084] The epoxy equivalent of the tetrafunctional amine-type epoxy resin is, for example, 90 to 140 g / eq, 100 to 135 g / eq, or 110 to 130 g / eq. When the epoxy equivalent is 140 g / eq or less, the number of epoxy groups per mass is sufficient, and adhesion to the object to be protected tends to be improved. In particular, when the tetrafunctional amine-type epoxy resin has a monoglycidylamino group, a diglycidylamino group, or both, the effect of improving adhesion due to the amine structure is also likely to be obtained. When the epoxy equivalent is 90 g / eq or more, it tends to be easier to prevent crosslinking points from becoming dense.

[0085] Commercially available tetrafunctional amine-type epoxy resins include, for example, "YH-434" and "YH-434L" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "Sumiepoxy ELM-434", "Sumiepoxy ELM-434L", and "Sumiepoxy ELM-434VL" manufactured by Sumitomo Chemical Co., Ltd.; "jER604" manufactured by Mitsubishi Chemical Corporation; "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi Gas Chemical Company, Inc.; and "TG3DAS" manufactured by Konishi Chemical Industry Co., Ltd.

[0086] When the thermosetting resin composition further contains a tetrafunctional amine-type epoxy resin, the content of the tetrafunctional amine-type epoxy resin is, for example, 1 to 16 mass%, 2 to 10 mass%, 3 to 10 mass%, or 5 to 8 mass%, based on the mass of resin A. When the content is within the above range, better detergent resistance is likely to be obtained. According to another embodiment, the thermosetting resin composition does not contain a tetrafunctional amine-type epoxy resin, or the content of the tetrafunctional amine-type epoxy resin may be less than 3 mass%, less than 2 mass%, or less than 1 mass%, based on the mass of resin A.

[0087] When the thermosetting resin composition contains a tetrafunctional amine-type epoxy resin, the total content of the trifunctional amine-type epoxy resin and the tetrafunctional amine-type epoxy resin is, for example, 3 to 28 mass%, 4 to 20 mass%, 6 to 16 mass%, or 8 to 10 mass%, based on the mass of resin A.

[0088] The higher the content of the trifunctional amine-type epoxy resin in the total of the trifunctional amine-type epoxy resin and the tetrafunctional amine-type epoxy resin, the better the detergent resistance may be obtained. The content of the trifunctional amine-type epoxy resin is, for example, 30% by mass or more, 50% by mass or more, 80% by mass or more, or 90% by mass or more based on the total mass of the trifunctional amine-type epoxy resin and the tetrafunctional amine-type epoxy resin. The upper limit may be 100% by mass.

[0089] (Optional Epoxy Resin) The thermosetting resin composition may further contain an epoxy resin such as a mono-, di-, penta- or higher functional amine-type epoxy resin or a non-amine-type epoxy resin. Examples of difunctional amine-type epoxy resins include "GAN" and "GOT" manufactured by Nippon Kayaku Co., Ltd. and "EP-3980" manufactured by ADEKA Corporation. Examples of non-amine type epoxy resins include bisphenol A type epoxy resins (such as "Epikote 828" manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins (such as "YDF-170" manufactured by Nippon Steel Chemical & Material Co., Ltd.), phenol novolac type epoxy resins (such as "Epikote 152, 154" manufactured by Mitsubishi Chemical Corporation; "EPPN-201" manufactured by Nippon Kayaku Co., Ltd.; and "DEN-438" manufactured by The Dow Chemical Company), o-cresol novolac type epoxy resins (such as "EOCN-125S, 103S, 104S" manufactured by Nippon Kayaku Co., Ltd.), heterocycle-containing epoxy resins (such as "Araldite PT810" manufactured by Chiba Specialty Chemicals Inc.), and alicyclic epoxy resins (such as "ERL4234, 429" manufactured by UCC). 9, 4221, 4206, etc.), epoxy resins having a dicyclopentadiene skeleton ("HP-7200" and "HP-7200H" manufactured by DIC Corporation), multifunctional epoxy resins ("Epon1031S" manufactured by Mitsubishi Chemical Corporation; "Araldite 0163" manufactured by Chiba Specialty Chemicals Co., Ltd.; "Denacol EX-611, EX-614, EX-614B, EX-622, EX-512, EX-521, EX-421, EX-411, EX-321" manufactured by Nagase ChemteX Corporation; "PB4700" and "EHPE3150" manufactured by Daicel Corporation; "KR470" manufactured by Shin-Etsu Chemical Co., Ltd.; "BATG" manufactured by Resonac Inc.; "jER157S70" manufactured by Mitsubishi Chemical Corporation, etc.).

[0090] The thermosetting resin composition may contain, as an optional epoxy resin, for example, a polyfunctional epoxy resin, a trifunctional non-amine type epoxy resin, or a tetrafunctional or higher non-amine type epoxy resin.

[0091] When the thermosetting resin composition further contains a non-amine-type epoxy resin, the content of the non-amine-type epoxy resin is, for example, 1 to 20% by mass, or 5 to 18% by mass, based on the mass of Resin A. When the content is within the above range, better cleaning agent resistance is likely to be obtained. According to another embodiment, the thermosetting resin composition may not contain a non-amine-type epoxy resin, or the content may be less than 5% by mass, less than 3% by mass, or less than 1% by mass. It is presumed that in a cured film obtained from a thermosetting resin composition containing a non-amine-type epoxy resin and a trifunctional amine-type epoxy resin, a concentration gradient occurs between the substrate side and the surface side within the cured film due to the difference in polarity, and the concentration of the trifunctional amine-type epoxy resin is higher on the substrate side.

[0092] The higher the content of the trifunctional amine-type epoxy resin in the epoxy resin, the more excellent the detergent resistance tends to be. The content of the trifunctional amine-type epoxy resin in the epoxy resin is, for example, 10 mass% or more, 30 mass% or more, 50 mass% or more, or 80 mass% or more based on the total mass of the epoxy resin. The upper limit may be 100 mass%.

[0093] The total content of epoxy resins contained in the thermosetting resin composition is, for example, 4 to 28% by mass, 5 to 20% by mass, 6 to 16% by mass, or 8 to 10% by mass, based on the mass of resin A. When the content is within the above range, flexible printed circuit boards and electronic components with good insulation reliability, low warpage, and weather resistance are easily obtained. When the content of trifunctional amine-type epoxy resins in the epoxy resin is high, good cleaning agent resistance tends to be obtained even when the total content of epoxy resins contained in the thermosetting resin composition is low. The lower the total content of epoxy resins, the more likely it is that impurities derived from the epoxy resins will be reduced from being mixed into the thermosetting resin composition, improving the insulation reliability of the flexible printed circuit board. Examples of impurities derived from epoxy resins include chlorine derived from epichlorohydrin, a raw material for epoxy resins.

[0094] For example, the thermosetting resin composition contains 1 to 16% by mass of a trifunctional amine-type epoxy resin based on the mass of resin A. For example, the thermosetting resin composition contains 1 to 5% by mass of a trifunctional amine-type epoxy resin based on the mass of resin A, and 3 to 10% by mass of a tetrafunctional amine-type epoxy resin based on the mass of resin A. For example, the thermosetting resin composition contains 1 to 5% by mass of a trifunctional amine-type epoxy resin based on the mass of resin A, 3 to 10% by mass of a tetrafunctional amine-type epoxy resin based on the mass of resin A, and 6 to 20% by mass of a non-amine-type epoxy resin based on the mass of resin A. The non-amine-type epoxy resin may be a tetrafunctional or higher epoxy resin having four or more epoxy groups.

[0095] [Organic Solvent] The thermosetting resin composition may further contain an organic solvent. Examples of the organic solvent include polar solvents such as N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), 3-methoxy-N,N-dimethylpropanamide (MPA), N,N'-dimethylformamide, N,N'-dimethylpropyleneurea [1,3-dimethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one], dimethyl sulfoxide, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and sulfolane; aromatic hydrocarbon solvents such as xylene and toluene; and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone. The organic solvent preferably contains at least one selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), and 3-methoxy-N,N-dimethylpropanamide (MPA), and more preferably contains at least one selected from the group consisting of N-ethyl-2-pyrrolidone (NEP), γ-butyrolactone (GBL), and 3-methoxy-N,N-dimethylpropanamide (MPA).

[0096] The organic solvent may be any of the organic solvents listed as examples of organic solvents that can be used in the reaction between a polyol and a polyisocyanate. The organic solvent may be, for example, the same organic solvent as that used in the reaction between polyisocyanate A and a tricarboxylic acid compound. The organic solvent may be γ-butyrolactone, particularly from the viewpoints of printability such as defoaming properties and leveling properties, and suppressing outflow (bleeding) of the thermosetting resin composition between wirings.

[0097] The content of the organic solvent can be determined appropriately depending on the application of the thermosetting resin composition. For example, when the composition is applied by screen printing, the content is, for example, 20 to 100 mass %, 30 to 90 mass %, or 40 to 80 mass % based on the total mass of the thermosetting resin composition.

[0098] [Optional Components] The thermosetting resin composition may further contain, as necessary, a resin other than a resin having an acid anhydride group or a carboxy group; a filler; a surfactant such as an antifoaming agent or a leveling agent; a colorant such as a dye or a pigment; a heat stabilizer, an antioxidant, a flame retardant, a lubricant, or the like.

[0099] When the thermosetting resin composition contains a filler, there is a tendency for at least one of the following to be improved: an improvement in the thixotropy coefficient, film formability, weather resistance of the protective film, printability, etc. Examples of the filler include inorganic fillers (inorganic fillers) and organic fillers (organic fillers). The fillers can be used alone or in combination of two or more.

[0100] Examples of inorganic fillers include silica (SiO ２ ), alumina (Al ２ O ３ ), titania (TiO ２ ), tantalum oxide (Ta ２ O ５ ), zirconia (ZrO ２ ), silicon nitride (Si ３ N ４ ), barium titanate (BaO.TiO ２ ), barium carbonate (BaCO ３ ), lead titanate (PbO.TiO ２), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), gallium oxide (Ga ２ O ３ ), spinel (MgO.Al ２ O ３ ), mullite (3Al ２ O ３ 2SiO ２ ), cordierite (2MgO 2Al ２ O ３ / 5SiO ２ ), talc (3MgO.4SiO ２ ・H ２ O), aluminum titanate (TiO ２ -Al ２ O ３ ), yttria-containing zirconia (Y ２ O ３ -ZrO ２ ), barium silicate (BaO.8SiO ２ ), boron nitride (BN), calcium carbonate (CaCO ３ ), calcium sulfate (CaSO ４ ), zinc oxide (ZnO), magnesium titanate (MgO.TiO ２ ), barium sulfate (BaSO ４ ), carbon (C), hydrotalcite (Mg ４ Al ２ (OH) １２ CO ３ ・3H ２ O) and the like.

[0101] Examples of organic fillers include fine particles of resins having amide bonds, imide bonds, ester bonds, or ether bonds, from the viewpoint of heat resistance and mechanical properties. For example, fine particles of polyimide resins or precursors thereof, polyamideimide resins or precursors thereof, or polyamide resins can be used as the organic filler.

[0102] The content of the filler is, for example, 1 to 100% by mass, 3 to 50% by mass, or 5 to 30% by mass, based on the mass of resin A. When the content is 1% by mass or more, tackiness after curing is suppressed, and it is easy to prevent the film from sticking to a substrate, etc. When the content is 100% by mass or less, it is easy to prevent warping of the cured film of the thermosetting resin composition.

[0103] When the thermosetting resin composition contains a surfactant such as an antifoaming agent or a leveling agent, the workability during film formation and the film properties before and after curing tend to be improved. The content of the surfactant is, for example, 0.1 to 5 mass % or 0.5 to 3 mass % based on the mass of resin A.

[0104] [Production Method] The method for producing the thermosetting resin composition is not particularly limited. For example, a method can be applied in which resin A, a trifunctional amine-type epoxy resin, and optional components such as an organic solvent and an antifoaming agent, if necessary, are mixed by a mixing method such as roll mixing or mixer mixing, which is used in the production of ordinary paints, inks, and pastes. Each component can be added sequentially to a mixing container. Alternatively, a set for a thermosetting resin composition described below can be used, and the first and second parts can be added to the mixing container.

[0105] <Set for Thermosetting Resin Composition> In some embodiments, the set for thermosetting resin composition is used to obtain a thermosetting resin composition and includes a first part containing a resin having an acid anhydride group or a carboxy group and a second part containing a trifunctional amine-type epoxy resin. Use of the set for thermosetting resin composition allows for stable storage of each component. When used to obtain a thermosetting resin composition further containing an optional epoxy resin, such as a tetrafunctional amine-type epoxy resin, the second part may contain the optional epoxy resin. The first part, the second part, or both may contain optional components, such as an organic solvent, a filler, an antifoaming agent, etc. The set for thermosetting resin composition may be a two-part set consisting of the first part and the second part, or may be a three-part or more-part set further including one or more parts containing at least one component selected from resin A, other resins, trifunctional amine-type epoxy resins, other epoxy resins, organic solvents, fillers, antifoaming agents, etc.

[0106] <Cured Product of Thermosetting Resin Composition> In some embodiments, a cured product can be obtained using the thermosetting resin composition of the above embodiment or the set for a thermosetting resin composition of the above embodiment. Examples of the cured product include a cured film, a film, a sheet, etc. A cured product such as a cured film, a film, or a sheet may be a protective film. The cured product can be obtained, for example, by applying the thermosetting resin composition to a substrate, obtaining a coated film, and then thermally curing the coated film. The coated film may be dried before thermal curing. The cured product may be, for example, a protective film for a flexible printed circuit board; it may be a protective film for a flexible printed circuit board having a copper foil and a polyimide substrate in contact with the copper foil.

[0107] Examples of application methods include spin coating, casting, dipping, dispensing, and printing methods such as relief printing, intaglio printing, offset printing, lithographic printing, relief reverse offset printing, screen printing, and gravure printing. The heating temperature during thermal curing is, for example, 60 to 200° C., 80 to 180° C., or 100 to 150° C. The heating time is, for example, 10 to 150 minutes, or 30 to 120 minutes.

[0108] <Flexible Printed Circuit Board and Electronic Component> In some embodiments, the flexible printed circuit board may be a flexible printed wiring board, and the flexible printed wiring board may include, for example, at least a substrate on which a wiring pattern is formed, a protective film covering at least a portion of the wiring pattern, and a plating layer covering at least a portion of the wiring pattern. In some embodiments, the flexible printed circuit board may be a flexible circuit board further including a flexible printed wiring board and an electronic component such as a semiconductor device. The flexible printed circuit board has excellent cleaning agent resistance because the protective film is the cured product of the above embodiment.

[0109] Examples of the substrate include a polyimide film, a polyimide film with an epoxy adhesive layer, etc. The thickness of the substrate is, for example, 10 to 200 μm, or 20 to 100 μm.

[0110] The wiring pattern may be formed of a material containing copper. The wiring pattern has a wiring width of, for example, 5 to 200 μm or 10 to 100 μm. The plating layer may be formed of a material containing Sn, Ni, or Au.

[0111] A method for manufacturing a flexible printed wiring board includes, for example, preparing a substrate on which a wiring pattern is formed, printing the thermosetting resin composition of the embodiment so as to cover at least a portion of the wiring pattern, curing the printed thermosetting resin composition to form a protective film, and forming a plating layer so as to cover at least a portion of the wiring pattern.

[0112] The conditions for thermal curing are, from the viewpoints of preventing oxidation of the wiring such as copper and obtaining low warpage and flexibility suitable for a protective film, for example, 80 to 180° C., 90 to 160° C., or 120 to 150° C. The heating time is, from the viewpoints of preventing oxidation of the wiring and obtaining low warpage and flexibility suitable for a protective film, for example, 30 to 120 minutes, or 50 to 90 minutes.

[0113] In some embodiments, the thermosetting resin composition of the above embodiment is suitable for use as a material for forming an overcoat material for electronic components, a liquid encapsulant, an interlayer insulating film, a surface protective film, a solder resist layer, an adhesive layer, etc. Examples of electronic components include flexible printed circuit boards such as COF (Chip On Film) and TAB (Tape Automated Bonding), as well as semiconductor elements such as integrated circuits, transistors, and diodes, semiconductor devices including semiconductor elements and semiconductor packages, modules, rigid printed circuit boards, and displays such as liquid crystal displays and organic EL displays.

[0114] Examples of embodiments of the present invention are listed below. The present invention is not limited to the following embodiments. (1) A thermosetting resin composition containing a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group, and a trifunctional amine-type epoxy resin. (2) The thermosetting resin composition according to (1) above, in which the trifunctional amine-type epoxy resin comprises an epoxy resin represented by the above formula (E1). (3) The thermosetting resin composition according to (1) or (2) above, in which the content of the trifunctional amine-type epoxy resin is 1 to 16 mass% based on the mass of the resin. (4) The thermosetting resin composition according to any one of (1) to (3) above, further containing a tetrafunctional amine-type epoxy resin. (5) The thermosetting resin composition according to (4) above, in which the tetrafunctional amine-type epoxy resin comprises an epoxy resin represented by the above formula (E2). (6) The thermosetting resin composition according to (4) or (5) above, wherein the content of the tetrafunctional amine-type epoxy resin is 1 to 16 mass% based on the mass of the resin. (7) The thermosetting resin composition according to any one of (1) to (6) above, further comprising an epoxy resin other than the amine-type epoxy resin. (8) The thermosetting resin composition according to any one of (1) to (7) above, wherein the total content of epoxy resins is 4 to 28 mass% based on the mass of the resin. (9) The thermosetting resin composition according to any one of (1) to (8) above, wherein the resin comprises a polyamideimide having at least one group selected from the group consisting of an acid anhydride group and a carboxy group. (10) The thermosetting resin composition according to any one of (1) to (9) above, wherein the resin comprises a polyamideimide having at least one group selected from the group consisting of an acid anhydride group and a carboxy group and a urethane bond. (11) The thermosetting resin composition according to (9) or (10) above, wherein the polyamideimide contains a structure derived from a polycarbonate diol represented by the above formula (P1). (12) The thermosetting resin composition according to any one of (9) to (11) above, wherein the polyamideimide contains a structure represented by the above formula (P2). (13) The thermosetting resin composition according to any one of (1) to (12) above, which is used for a protective film of a flexible printed circuit board having a polyimide substrate and a copper foil in contact with the polyimide substrate.(14) A set for thermosetting resin compositions, which is used to obtain the thermosetting resin composition according to any one of (1) to (13) above, and which comprises a first part containing the resin and a second part containing the trifunctional amine-type epoxy resin. (15) A cured product obtained using the thermosetting resin composition according to any one of (1) to (13) above or the set for thermosetting resin compositions according to (14) above. (16) A film obtained using the thermosetting resin composition according to any one of (1) to (13) above or the set for thermosetting resin compositions according to (14) above. (17) A flexible printed circuit board obtained using the thermosetting resin composition according to any one of (1) to (13) above or the set for thermosetting resin compositions according to (14) above. (18) An electronic component obtained using the thermosetting resin composition according to any one of (1) to (13) above or the set for thermosetting resin compositions according to (14) above. The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-116179, filed on July 14, 2023, the entire disclosure of which is incorporated herein by reference.

[0115] The embodiments of the present invention will be described in more detail with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0116] <Synthesis of Resin A> A reaction vessel equipped with a stirrer, a thermometer, and a condenser was charged with polycarbonate diol (1) (R ｐ contains a structure derived from 1,4-cyclohexanedimethanol and a structure derived from 1,6-hexanediol in a molar ratio of 1:1, and the average value n is in the range of 4 to 6. ｐ contains a structure derived from 1,4-cyclohexanedimethanol and a structure derived from 1,6-hexanediol in a molar ratio of 3:1, and the average value n is in the range of 4 to 6. ｐThe structure is derived from 1,6-hexanediol, and the average value n is in the range of 21.5 to 23.5. 76.74 g (0.04 mol) of 4,4'-diphenylmethane diisocyanate was added. Furthermore, 59.37 g (0.24 mol) of 4,4'-diphenylmethane diisocyanate, 27.56 g (0.16 mol) of tolylene diisocyanate mixture (1) (a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in a mass ratio of 80:20), and 206.40 g of γ-butyrolactone were added to the reaction vessel and stirred to obtain a mixture. The mixture was heated to 150°C to dissolve all the raw materials, and the mixture was allowed to react for 4 hours to produce a polyisocyanate having urethane bonds.

[0117] Next, the temperature of the resulting reaction liquid was lowered to 70°C, and 55.76 g (0.29 mol) of trimellitic anhydride was added and completely dissolved, after which 13.86 g (0.06 mol) of 4,4'-diphenylmethane diisocyanate, 6.45 g (0.04 mol) of the tolylene diisocyanate mixture (1), and 170.51 g of γ-butyrolactone were added and stirred to obtain a mixture. The mixture was then heated to 120°C to dissolve all of the raw materials, and the reaction was carried out for 1 hour.

[0118] The temperature of the resulting reaction solution was adjusted to react at 160°C for 5 hours, at 135°C for 1 hour, and at 120°C for 1 hour. Subsequently, 5.36 g (0.06 mol) of 2-butanone oxime and 142.27 g of γ-butyrolactone were added to terminate the reaction. A polyamideimide-containing solution having urethane bonds (solid content: 40.5% by mass, hereinafter referred to as "varnish") was obtained.

[0119] The polyamideimide had a number average molecular weight (Mn) of 6,900, a weight average molecular weight (Mw) of 46,500, a polydispersity (Mw / Mn) of 6.72, and an acid value of 11 mgKOH / g.

[0120] The GPC measurement conditions for the number average molecular weight and weight average molecular weight of polyamideimide, and the method for measuring the acid value are shown below. (Number average molecular weight, weight average molecular weight) Liquid delivery pump: "LC-20AD" manufactured by Shimadzu Corporation Autosampler: "SIL-20A HT" manufactured by Shimadzu Corporation Column oven: "CTO-20A" manufactured by Shimadzu Corporation UV detector: "SPD-M20A" manufactured by Shimadzu Corporation Column: Gelpack "GL-A160-S" and "GL-A150-S" manufactured by Hitachi High-Tech Corporation were connected in series. Column size: inner diameter 7.8 mm, length 300 mm (GL-A160-S, GL-A150-S) Eluent: tetrahydrofuran (THF) Sample concentration: resin 10 mg / THF 2.5 mg Injection volume: 20 μL Flow rate: 1 mL / min Column temperature: 40°C Molecular weight standard: standard polystyrene (Tosoh Corporation, "PStQuick B, PStQuick C, PStQuick D")

[0121] (Acid Value) 1 g of polyamideimide was precisely weighed into a stoppered flask, and 100 g of N-methylpyrrolidone was added and dissolved. A few drops of thymol blue test solution were added to the resulting solution as an indicator, and the solution was titrated with 0.1 mol / L aqueous potassium hydroxide solution until a brown color appeared, which persisted for 30 seconds. The inflection point on the titration curve was taken as the endpoint. A 25 mL burette manufactured by AS ONE Corporation was used as the titrator. The acid value was calculated from the volume of 0.1 mol / L aqueous potassium hydroxide solution required for titration using the following formula: Acid value = a × F × 5.611 / amount of polyamideimide (g), where a: volume of 0.1 mol / L aqueous potassium hydroxide solution (mL), and F: titer of 0.1 mol / L aqueous potassium hydroxide solution.

[0122] <Preparation of Thermosetting Resin Composition> [Example 1] Polyamideimide varnish, epoxy resin, antifoaming agent, and solvent were added to a planetary mixer (AR-250 manufactured by Thinky Corporation). The mixture was kneaded at a rotation speed of 2,000 rpm for a rotation time of 3 minutes to obtain a thermosetting resin composition. Table 1 shows the content (parts by mass) of each component. The polyamideimide content in Table 1 is the solid content.

[0123] [Examples 1 to 10 and Comparative Examples 1 to 7] Thermosetting resin compositions were obtained in the same manner as in Example 1, except that the epoxy resin and the like were changed to the components and contents shown in Tables 1 and 2. The polyamideimide contents in Tables 1 and 2 are solid content.

[0124]

[0125]

[0126] The components used in the examples and comparative examples are listed below. Polyamideimide: Polyamideimide obtained in Synthesis Example Epoxy Resin A: Trifunctional amine-modified epoxy resin (N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline, epoxy equivalent 95 g / eq, EP-3950S / manufactured by ADEKA Corporation) B: Tetrafunctional amine-modified epoxy resin (N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, epoxy equivalent 117 g / eq, YH-434L / manufactured by Nippon Steel Chemical & Material Co., Ltd.) C: Multifunctional butadiene-based epoxy resin (epoxy equivalent 165 g / eq, PB4700 / manufactured by Daicel Corporation) D: Tetrafunctional siloxane-based epoxy resin (epoxy equivalent 200 g / eq, KR470 / manufactured by Shin-Etsu Chemical Co., Ltd.) E: tetrafunctional bisphenol A type epoxy resin (epoxy equivalent 124 g / eq, BATG / manufactured by Resonac Co., Ltd.) F: multifunctional cyclohexane type epoxy resin (epoxy equivalent 180 g / eq, EHPE3150 / manufactured by Daicel Corporation) G: multifunctional bisphenol A type epoxy resin (epoxy equivalent 207 g / eq, jER157S70 / manufactured by Mitsubishi Chemical Corporation) Defoamer: acrylic defoamer (Disparlon LF-1983, manufactured by Kusumoto Chemical Co., Ltd.) Solvent: γ-butyrolactone

[0127] <Evaluation> Flexible copper-clad laminates were produced using the thermosetting resin compositions by the following methods, and the cleaning agent resistance and warpage resistance were evaluated. The evaluation results are shown in Tables 1 and 2.

[0128] [Cleaning Agent Resistance] (Preparation of Flexible Copper-Clad Laminate) A flexible copper-clad laminate (20 mm long, 27 mm wide) was prepared, comprising a polyimide film (38 μm thick), a copper foil (sputtered copper, 8 μm thick), and a comb-shaped copper wiring (wiring pattern, copper wiring width / copper wiring spacing=10.0 μm / 10.0 μm, number of copper wirings: 17) with a Sn-plated layer (thickness: 0.2-0.3 μm) formed on the copper foil. A thermosetting resin composition was applied to this laminate by screen printing under the following conditions (4 mm long, 17 mm wide, dry film thickness: 10 μm). The applied thermosetting resin composition was cured by heating at 80°C for 3 minutes and then at 140°C for 30 minutes to form a protective film. The laminate with the protective film formed was used as a test specimen. Schematic diagrams of the test specimen are shown in FIGS. 1 and 2. FIG. 2 is an enlarged view of the area within the dashed line in FIG. 1. 1 and 2, 1 is a polyimide film, 2 is a wiring pattern, 3 is a protective film, and 100 is a test piece. (Printing conditions) Printer: "LS-34GX" manufactured by Newlong Precision Industry Co., Ltd. Mesh plate: "3D250 mesh plate" manufactured by Murakami Co., Ltd. Printing speed: 80 mm / sec

[0129] (Evaluation of Detergent Resistance) A hollow cylindrical plastic (inner diameter 7 mm) was attached to a test specimen using a silicone adhesive (Cemedine Super X2 manufactured by Cemedine Co., Ltd.) so that one end of the cylindrical side surface was in contact with the surface of the protective film. Glass cleaner (Windex SC manufactured by Johnson (containing water, alcohol, alkanolamine, surfactant, etc.)) was added to the inside of the hollow cylindrical plastic, and a cover film (PET film) was attached to the other end of the cylindrical side surface using a silicone adhesive. Figures 3 and 4 show schematic diagrams of the test specimen in contact with the glass cleaner. Figure 3 is a plan view, and Figure 4 is a perspective view. In Figures 3 and 4, 1 represents a polyimide film, 2 represents a wiring pattern, 3 represents a protective film, 11 represents the hollow cylindrical plastic, 12 represents the glass cleaner, 13 represents the cover film, and 100 represents the test specimen. A voltage of 20 V was applied to the test piece in an atmosphere of a temperature of 23° C. and a relative humidity of 60%, and the time (h) from the start of application until a short circuit occurred between the wirings was measured. ６ The point at which the resistance became less than Ω was determined to be the point at which a short circuit occurred between the wires.

[0130] [Low Warpage] (Preparation of Flexible Copper-Clad Laminate) A flexible copper-clad laminate (length 48 mm, width 35 mm) was prepared, which included a polyimide film (thickness 38 μm), copper foil (sputtered copper, thickness 8 μm), and copper wiring (wiring pattern) having a Sn-plated layer (thickness 0.2 to 0.3 μm) formed on the copper foil. A thermosetting resin composition was applied to this laminate by screen printing under the following conditions (length 48 mm, width 35 mm, dry film thickness 10 μm). The applied thermosetting resin composition was cured by heating at 80°C for 3 minutes and then at 140°C for 30 minutes to form a protective film. The laminate with the protective film formed was used as a test specimen. (Printing Conditions) Printer: "LS-34GX" manufactured by Newlong Precision Industry Co., Ltd. Mesh plate: "SUS200 mesh plate" manufactured by Murakami Co., Ltd. Printing speed: 80 mm / sec

[0131] (Evaluation of Low Warpage) After curing, the test piece was left to stand at room temperature (25° C.) for 24 hours. The test piece was placed on a surface plate with the protective film side facing downward, and the distance (mm) from the surface plate to the apex of the warpage of the flexible copper-clad wiring board was measured.

[0132] REFERENCE SIGNS LIST 1 Polyimide film 2 Wiring pattern 3 Protective film 11 Hollow cylindrical plastic 12 Glass cleaner 13 Cover film 100 Test piece

Claims

1. A thermosetting resin composition comprising a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group, and a trifunctional amine-type epoxy resin.

2. The thermosetting resin composition according to claim 1, wherein the trifunctional amine-type epoxy resin comprises an epoxy resin represented by the following formula (E1): (In the formula, R １ represents a divalent organic group.

3. The thermosetting resin composition according to claim 1 or 2, wherein the content of the trifunctional amine-type epoxy resin is 1 to 16 mass % based on the mass of the resin.

4. The thermosetting resin composition according to any one of claims 1 to 3, further comprising a tetrafunctional amine-type epoxy resin.

5. The thermosetting resin composition according to claim 4, wherein the tetrafunctional amine-type epoxy resin comprises an epoxy resin represented by the following formula (E2): (In the formula, R ２ represents a divalent organic group.

6. The thermosetting resin composition according to claim 4 or 5, wherein the content of the tetrafunctional amine-type epoxy resin is 1 to 16 mass % based on the mass of the resin.

7. The thermosetting resin composition according to any one of claims 1 to 6, further comprising an epoxy resin other than the amine-type epoxy resin.

8. The thermosetting resin composition according to any one of claims 1 to 7, wherein the total content of the epoxy resins is 4 to 28 mass % based on the mass of the resin.

9. The thermosetting resin composition according to any one of claims 1 to 8, wherein the resin comprises a polyamideimide having at least one group selected from the group consisting of an acid anhydride group and a carboxy group.

10. The thermosetting resin composition according to any one of claims 1 to 9, wherein the resin comprises a polyamideimide having a urethane bond and at least one group selected from the group consisting of an acid anhydride group and a carboxy group.

11. The thermosetting resin composition according to claim 9 or 10, wherein the polyamideimide contains a structure derived from a polycarbonate diol represented by the following formula (P1): (In the formula, R ｐ represents a divalent organic group having an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or a divalent organic group having an aliphatic hydrocarbon group having 1 to 18 carbon atoms (provided that the divalent organic group does not have an alicyclic hydrocarbon group), and n represents a number from 1 to 30. ｐ may be the same or different.) 12. The thermosetting resin composition according to any one of claims 9 to 11, wherein the polyamideimide contains a structure represented by the following formula (P2): (In the formula, R ｐ represents a divalent organic group having an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or a divalent organic group having an aliphatic hydrocarbon group having 1 to 18 carbon atoms (provided that the divalent organic group does not have an alicyclic hydrocarbon group), X represents a divalent organic group, and n represents a number from 1 to 30. ｐ may be the same or different. * indicates the bonding position with other structures.) 13. The thermosetting resin composition according to any one of claims 1 to 12, which is used as a protective film for a flexible printed circuit board having a polyimide substrate and a copper foil in contact with the polyimide substrate.

14. A set for a thermosetting resin composition, which is used to obtain the thermosetting resin composition according to any one of claims 1 to 13, and which comprises a first agent containing the resin and a second agent containing the trifunctional amine-type epoxy resin.

15. A cured product obtained by using the thermosetting resin composition according to any one of claims 1 to 13 or the set for a thermosetting resin composition according to claim 14.

16. A film obtained by using the thermosetting resin composition according to any one of claims 1 to 13 or the set for a thermosetting resin composition according to claim 14.

17. A flexible printed circuit board obtained by using the thermosetting resin composition according to any one of claims 1 to 13 or the set for a thermosetting resin composition according to claim 14.

18. An electronic part obtained by using the thermosetting resin composition according to any one of claims 1 to 13 or the set for a thermosetting resin composition according to claim 14.

Images