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

Abstract

To provide a thermosetting resin composition that yields a flexible printed circuit board with superior insulation reliability and reduced warpage.SOLUTION: A thermosetting resin composition contains (A) a resin having at least one group selected from the group consisting of acid anhydride groups and carboxy groups, (B) an ion trapping agent containing Zr, Mg, and Al, (C) an inorganic filler, and (D) an epoxy resin.SELECTED DRAWING: None

Description

[Technical field]

[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. [Background technology]

[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 wirings. The protective film can be formed using, for example, a thermosetting resin composition. The protective film is required to have excellent insulating reliability and flexibility.

[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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-275114 A Summary of the Invention [Problem to be solved by the invention]

[0005] Electronic devices are required to have higher performance, smaller size, and thinner profile. To achieve these goals, flexible printed circuit boards are also expected to have high performance, and protective films with better insulation reliability and flexibility are required.

[0006] Therefore, the present disclosure provides a thermosetting resin composition capable of producing a flexible printed circuit board having excellent insulation reliability and suppressed warping. The present disclosure also provides a set including a first agent and a second agent for producing the thermosetting resin composition, and a cured product and a film obtained using the thermosetting resin composition or the set. Furthermore, the present disclosure provides a flexible printed circuit board and an electronic component having excellent insulation reliability and suppressed warping. [Means for solving the problem]

[0007] The following are examples of the present invention, but the present invention is not limited to the following examples. One embodiment relates to a thermosetting resin composition containing (A) a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group, (B) an ion trapping agent containing Zr, Mg, and Al, (C) an inorganic filler, and (D) an epoxy resin. Another embodiment relates to a set for a thermosetting resin composition, which is used to obtain the above-mentioned thermosetting resin composition and includes a first agent containing the resin and a second agent containing the trifunctional amine-type epoxy resin. Another embodiment relates to a cured product obtained using the above-mentioned thermosetting resin composition or the above-mentioned set for a thermosetting resin composition. Another embodiment relates to a film obtained using the above-mentioned thermosetting resin composition or the above-mentioned set for a thermosetting resin composition. Another embodiment relates to a flexible printed circuit board obtained using the above-mentioned thermosetting resin composition or the above-mentioned set for a thermosetting resin composition. Another embodiment relates to an electronic component obtained using the above-mentioned thermosetting resin composition or the above-mentioned set for a thermosetting resin composition. Effect of the Invention

[0008] According to the present disclosure, a thermosetting resin composition capable of producing a flexible printed circuit board having excellent insulation reliability and suppressed warping is provided. Also, according to the present disclosure, a set including a first agent and a second agent for producing the thermosetting resin composition is provided, as well as a cured product and a film obtained by using the thermosetting resin composition or the set for the thermosetting resin composition. Furthermore, according to the present disclosure, a flexible printed circuit board and an electronic component having excellent insulation reliability and suppressed warping are provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic front view showing a test piece for evaluating insulation reliability and detergent resistance prepared in the examples. [Diagram 2] FIG. 2 is a schematic front view showing an enlarged wiring portion of the test piece shown in FIG. [Diagram 3] FIG. 3 is a schematic front view showing a state in which a test piece is brought into contact with a cleaning agent in an example. [Figure 4] FIG. 4 is a schematic perspective view showing a state in which a test piece is brought into contact with a cleaning agent in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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. A combination of multiple embodiments is 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 the 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 limit numerical value and the lower limit numerical value described in stages in this disclosure to form a stepped numerical range. The upper limit numerical value and the lower limit numerical value described in this disclosure may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple types of corresponding substances. When multiple types of 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 the present disclosure, each structure in a resin or polymer may contain multiple types of corresponding structures. When multiple types of structures corresponding to each structure exist in a resin or polymer, the content or amount of each structure means the total content or amount of the multiple types of structures present in the resin or polymer, unless otherwise specified. In the present disclosure, the particles corresponding to each component may include multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified. In the present disclosure, a "layer" includes a continuous layer and a discontinuous layer. The thickness of a "layer" may be uniform or non-uniform. The outer edge of a "layer" in the planar direction and the outer edge in the thickness direction may be clear or unclear. The same applies to a "film." When an embodiment of the present disclosure is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to the relationship shown in the drawings.

[0012] <Thermosetting resin composition> In some embodiments, the thermosetting resin composition contains (A) a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group (in the present disclosure, this may be simply referred to as "(A) resin"), (B) an ion trapping agent containing Zr, Mg, and Al (in the present disclosure, this may be simply referred to as "(B) ion trapping agent"), (C) an inorganic filler, and (D) an epoxy resin. The thermosetting resin composition may further contain any optional component.

[0013] [(A) Resin] The (A) resin is a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group (sometimes referred to as an "acid anhydride group or a carboxy group" in the present disclosure). In the present disclosure, the acid anhydride group is a carboxylic acid anhydride group. Examples of the (A) resin include phenolic resins, acrylic resins, polyurethanes, polybutadienes, water-added polybutadienes, polyesters, polycarbonates, polyethers, polysulfones, polytetrafluororesins, polysilicones, melamine resins, polyamides, polyamideimides, polyimides, and other resins having 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. The 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 insulation 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 "resistance to cleaning agents". 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. The 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 the polyisocyanate with a tricarboxylic acid compound. The polyamideimide can contain a polyurethane structure in the molecule from the viewpoint of improving flexibility. The polyol can be used alone or in combination of two or more kinds. The polyisocyanate can be used alone or in combination of two or more kinds.

[0016] (Polyol) Examples of the polyol include alicyclic diols, aliphatic diols, and diol compounds represented by the following formula (P1). The diol may include an alicyclic diol from the viewpoint of obtaining a cured product having excellent flexibility while maintaining high insulation reliability. The diol may include 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-cyclohexane diol, 1,3-cyclohexane diol, 1,4-cyclohexane diol, 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, 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] [ka]

[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 (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. 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, p The copolymerized carbonate 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. 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 that is a copolymer using 1,4-cyclohexanedimethanol and 1,6-hexanediol. A copolymeric carbonate diol having a molar ratio of 1,4-cyclohexanedimethanol and 1,6-hexanediol of 3 / 1 is commercially available from UBE as "UM-90(3 / 1)"; a copolymeric carbonate diol having a molar ratio of 1,4-cyclohexanedimethanol and 1,6-hexanediol of 1 / 1 is commercially available from UBE as "UM-90(1 / 1)"; and a copolymeric carbonate diol having a molar ratio of 1,4-cyclohexanedimethanol and 1,6-hexanediol of 1 / 3 is commercially available from UBE as "UM-90(1 / 3)".

[0025] The diol compound represented by formula (P1) is, for example, p However, it may be a carbonate diol containing a structure derived from a diol having a divalent organic group having an aliphatic hydrocarbon group. In this 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. pExamples of the diol compound in which is a divalent organic group having an aliphatic hydrocarbon group 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. 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 shown 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 resistance. From the same viewpoint, the molar ratio is, for example, 2 or less, 1 or less, or 0.6 or less.

[0029] From the viewpoint of easily imparting properties such as improved glass transition temperature and improved modulus of elasticity and obtaining excellent insulation reliability, the ratio of the structure derived from the alicyclic diol may be, for example, 0.1% by mass or more, 3% by mass or more, or 5% by mass or more based on the mass of the polyamideimide. From the viewpoint of easily suppressing the improvement of the crystallinity of the polyamideimide and easily obtaining good solubility in a solvent, the ratio of the structure derived from the alicyclic diol may be, for example, 30% by mass or less, 25% by mass or less, or 20% by mass or less based on the mass of the polyamideimide. In calculating the ratio, the "structure derived from the alicyclic diol" means the portion obtained by removing two hydroxyl groups from the alicyclic diol. For example, when the alicyclic diol is 1,4-cyclohexanedimethanol, the portion obtained by removing two hydroxyl groups from 1,4-cyclohexanedimethanol is regarded as 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, and the like.

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

[0032] (Polyisocyanate) An example of the polyisocyanate is a diisocyanate compound represented by the following formula (P3).

[0033] [ka]

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

[0035] Examples of the divalent organic group represented by X in formula (P3) include an alkylene group having 1 to 20 carbon atoms; an arylene group such as a phenylene group or a naphthylene group that 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; an organic group in which two of the arylene groups are bonded via a lower alkylene group having 1 to 5 carbon atoms, an oxy group (-O-), a carbonyl group (-CO-), or a sulfonyl group (-SO2-); and an organic group in which two of the lower alkylene groups having 1 to 5 carbon atoms are bonded via an arylene group. The number of carbon atoms in the alkylene group may be, for example, 1 to 18. 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 obtained by hydrogenating these groups.

[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 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 aromatic isocyanates such as 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, and the like, 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 between the polyol and the polyisocyanate can be carried out by heating and condensing them 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 kinds.

[0041] The non-nitrogen-containing polar solvent is selected from, for example, ether-based 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-based solvents such as γ-butyrolactone and cellosolve acetate; ketone-based solvents such as cyclohexanone and methyl ethyl ketone; and aromatic hydrocarbon-based solvents such as toluene and xylene.

[0042] A solvent capable of dissolving the resin produced 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, can efficiently carry out a 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] The reaction temperature is, for example, 70° C. or more, 75° C. or more, or 80° C. or more from the viewpoint of preventing the reaction from taking a long time. The reaction temperature is, for example, 210° C. or less, 190° C. or less, or 180° C. or less 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 employed, and the like.

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

[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, or a metal or semimetal compound such as tin, zinc, titanium or cobalt.

[0046] The mixing ratio when reacting the polyol with the polyisocyanate may be appropriately adjusted, for example, taking into consideration 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] To synthesize polyisocyanate A having an isocyanate group at its terminal, the mixing 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 contains, for example, a structure represented by the following formula (P2).

[0049] [ka]

[0050] In the formula, R prepresents 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. R in formula (P1) p and X are explained in the 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.

[0052] (Tricarboxylic acid compounds) The tricarboxylic acid compound may be a trivalent polycarboxylic acid having an acid anhydride group and 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] [ka]

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

[0055] [ka]

[0056] In formula (P5), R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a phenyl group, and Y represents -CH2-, -CO-, -SO2- 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 which is a divalent polycarboxylic acid or a derivative thereof, or a tetracarboxylic acid compound which is a tetravalent polycarboxylic acid or a derivative thereof may be used.

[0059] (Reaction method, etc.) The above-mentioned organic solvents 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 synthesizing polyamideimide well, the amount of the 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 the solvent used is, for example, 5.0 times (mass ratio) or less.

[0061] The reaction temperature is, for example, 70° C. or more, 75° C. or more, or 80° C. or more from the viewpoint of preventing the reaction from taking a long time. The reaction temperature is, for example, 210° C. or less, 190° C. or less, or 180° C. or less 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 employed, and the like.

[0062] Polyisocyanate A may be reacted with a tricarboxylic acid compound together with another polyisocyanate (sometimes referred to as "polyisocyanate B" in the present disclosure) to obtain a polyamideimide. 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 polyisocyanate having three or more valences. Each of polyisocyanate A and polyisocyanate B may be used alone or in combination of two or more kinds.

[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 the above range, good adhesion between the cured product and an adherend such as a circuit board is easily obtained.

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

[0066] In the reaction between polyisocyanate A and 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 carboxyl 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 carboxyl 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 carboxyl groups to acid anhydride groups is 1.4 or less, 1.3 or less, or 1.2 or less.

[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 a solvent and resistance to insolubilization during synthesis.

[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 a solvent and resistance to insolubilization during synthesis.

[0069] In the present disclosure, the number average molecular weight and the 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 the 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, bending 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 can be measured by neutralization titration. Details of the method for measuring the acid value are shown in the Examples.

[0071] The polyamideimide obtained by the above-mentioned 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 has a carboxy group or an acid anhydride group at the end of the molecular chain, flexibility and insulation reliability can be improved.

[0072] The (A) resin 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 a polyurethane having an acid anhydride group or a carboxy group. The polyurethane may contain an ester bond in the molecule from the viewpoint of improving flexibility. The polyurethane may contain a fluorene structure or a cardo structure. In some embodiments, the thermosetting resin composition contains a polyimide having an acid anhydride group or a carboxy group. The polyimide may contain a carbonate structure in the molecule from the viewpoint of improving flexibility. The polyimide may contain a fluorene structure or a cardo structure.

[0073] [(B) Ion trapping agent] The (B) ion trapping agent is an ion trapping agent containing Zr, Mg, and Al. The (B) ion trapping agent is only required to have a function of trapping ions, and preferably has a function of trapping cations and anions. Examples of ions to be trapped include cations such as sodium ions, potassium ions, calcium ions, magnesium ions, copper ions, tin ions, and silver ions, and anions such as chloride ions, fluorine ions, and bromine ions. By including the (B) ion trapping agent, the thermosetting resin composition can efficiently trap anions that cause corrosion of wiring and cations derived from the wiring, thereby preventing the occurrence of migration and improving the insulation reliability of the flexible printed circuit board.

[0074] The (B) ion trapping agent may have a particle shape containing Zr, Mg, and Al. The average particle diameter of the particles containing Zr, Mg, and Al is, for example, 100 to 1,000 nm, 200 to 800 nm, or 300 to 700 nm. When the content is within the above range, good insulation reliability and the effect of preventing warping are easily obtained. In particular, when the average particle diameter is 300 nm or more, the (B) ion trapping agent tends to be easily dispersed in the thermosetting resin composition. When the dispersion state is good, shrinkage due to curing of the thermosetting resin composition can be prevented, and warping of the flexible printed circuit board can be suppressed. When the average particle diameter is 1,000 nm or less, fine particles of the (B) ion trapping agent can be dispersed and present in the cured product, so that ions tend to be efficiently captured. In the present disclosure, the average particle diameter of the (B) ion trapping agent can be measured using a SEM (scanning electron microscope). For example, 50 particles are arbitrarily selected from the SEM image of the (B) ion trapping agent, and the maximum particle diameter of each particle is measured. The arithmetic mean value of the obtained measured values ​​(50 particles) is regarded as the average particle size of the ion trapping agent (B).

[0075] As the (B) ion trapping agent, for example, commercially available products such as IXEPLAS-A1 (Toagosei Co., Ltd.) and IXEPLAS-A2 (Toagosei Co., Ltd.) can be used.

[0076] The content of the (B) ion trapping agent is, for example, 1 to 60 mass%, 2 to 50 mass%, or 5 to 40 mass% based on the (A) resin. When the content is within the above range, good insulation reliability and the effect of preventing warping are easily obtained. In particular, when the content is 40 mass% or less, the cleaning agent resistance described below tends to be improved. The reason for this is presumed to be that when the content is 40 mass% or less, the curing of the thermosetting resin composition proceeds sufficiently, and good adhesion between the cured product and the adherend is easily obtained. However, the present invention is not limited by this reason. From the viewpoint of obtaining good insulation reliability, prevention of warping, and cleaning agent resistance, the content of the (B) ion trapping agent may be, for example, 5 to 30 mass%, 6 to 20 mass%, or 7 to 15 mass% based on the (A) resin.

[0077] [(C) Inorganic filler] (C) Examples of inorganic fillers include, for example, silica (SiO2), alumina (Al2O3), titania (TiO2), tantalum oxide (Ta2O5), zirconia (ZrO2), silicon nitride (Si3N4), barium titanate (BaO·TiO2), barium carbonate (BaCO3), lead titanate (PbO·TiO2), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), gallium oxide (Ga2O3), spinel (MgO·Al2O3), mullite (3Al2O3·2SiO2), Cordierite (2MgO·2Al2O3 / 5SiO2), talc (3MgO·4SiO2·H2O), aluminum titanate (TiO2-Al2O3), yttria-containing zirconia (Y2O3-ZrO2), barium silicate (BaO·8SiO2), boron nitride (BN), calcium carbonate (CaCO3), calcium sulfate (CaSO4), zinc oxide (ZnO), magnesium titanate (MgO·TiO2), barium sulfate (BaSO4), carbon (C), hydrotalcite (Mg4Al2(OH) 12 CO3·3H2O) and the like can be used, and one or more of these can be used. In the present disclosure, the inorganic filler (C) is a particle other than the "particle containing Zr, Mg, and Al."

[0078] The thermosetting resin composition containing the inorganic filler (C) tends to improve at least one of the thixotropy coefficient, film formability, weather resistance of the protective film, printability, etc. From the viewpoint of improving the strength of the cured product, the thermosetting resin composition preferably contains a silica filler. Silica fillers are easily available, and it is possible to select a filler having suitable properties such as particle size, shape, surface condition, etc. according to the purpose and apply it to the thermosetting resin composition. Furthermore, silica fillers are also preferred fillers in that they are less restricted by environmental regulations.

[0079] The average particle size of the (C) inorganic filler is, for example, 0.001 to 50 μm, 0.01 to 10 μm, or 0.1 to 1 μm. When the average particle size is 50 μm or less, a thermosetting resin composition having appropriate thixotropy according to the film-forming method is easily obtained. The maximum particle size of the (C) inorganic filler is, for example, 100 μm or less, 60 μm or less, or 40 μm or less. When the maximum particle size is 100 μm or less, a film having good appearance and adhesion is easily obtained. In the present disclosure, the average particle size of the (C) inorganic filler refers to the median diameter (D50) by a laser diffraction scattering method (volume basis).

[0080] The content of the (C) inorganic filler is, for example, 1 to 60 mass%, 2 to 50 mass%, or 5 to 20 mass% based on the (A) resin. If the content is 1 mass% or more, the viscosity and thixotropy of the thermosetting resin composition tend to be small, which prevents the thermosetting resin composition from flowing out during film formation and makes it easier to obtain a cured product with a desired film thickness. If the content is 100 mass% or less, the viscosity and thixotropy of the thermosetting resin composition tend to be large, which makes it easier to prevent voids and pinholes from occurring in the cured product, especially when the cured product is produced by printing.

[0081] When the (B) ion trapping agent is a particle containing Zr, Mg, and Al, the (B) ion trapping agent can also function as an inorganic filler. In this case, the total content of the (B) ion trapping agent and the (C) inorganic filler is, for example, 2 to 70 mass%, 4 to 60 mass%, or 10 to 50 mass% based on the (A) resin.

[0082] [(D) Epoxy resin] The thermosetting resin composition contains an epoxy resin (D). For example, the thermosetting resin composition may contain 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 having 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 having 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 having 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.

[0083] (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).

[0084] [ka] (In the formula, R 1represents a divalent organic group.

[0085] R 1 Examples of R include the groups exemplified in the description of X in the diisocyanate compound represented by the above formula (P3). 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 a phenylene group which is unsubstituted or 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.

[0086] By containing a trifunctional amine-type epoxy resin in the thermosetting resin composition, it is possible to obtain a flexible printed circuit board and an electronic component having excellent detergent resistance. The reason for this is presumed to be as follows. However, the present invention is not limited to the following. When the thermosetting resin composition contains a trifunctional amine-type epoxy resin, the adhesion between the cured product such as a protective film and the object to be protected such as a substrate with wiring is improved. In particular, when the object to be protected contains a film containing an imide bond, an amide bond, or an imide bond and an amide bond, such as a polyimide film, a polyamideimide film, or a polyamide film, the intermolecular interaction between the amine structure and the imide bond or amide bond contained in the film, which is similar to the polarity of the imide bond, is increased, and the adhesion is thought to be further improved. In addition, when the thermosetting resin composition contains a trifunctional amine-type epoxy resin, there is a tendency that a film with suppressed warping can be obtained. The more epoxy groups in one epoxy resin molecule, the denser the epoxy resin becomes as a crosslinking point, and the more likely the cured product such as a protective film is to warp. It is thought that the fewer the epoxy groups in one epoxy resin molecule, the less dense it is, the more suppressed the shrinkage, and the less warping of the cured product. On the other hand, if the amine-type epoxy resin has two or less functional groups, the network structure caused by the epoxy resin cannot be introduced into the cured product. The trifunctional amine-type epoxy resin can introduce a network structure into the cured product and can easily prevent the product from becoming dense. For these reasons, it is believed that penetration of the cleaning agent into the interface between the cured product and the object to be protected is suppressed, thereby preventing short circuits caused by the cleaning agent between wiring and short circuits due to migration caused by metal deposition.

[0087] 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, and the adhesion to the object to be protected tends to be improved. In particular, when the trifunctional amine-type epoxy resin has a monoglycidylamino group, a diglycidylamino group, or both, the effect of improving the adhesion due to the amine structure is easily obtained. When the epoxy equivalent is 70 g / eq or more, it tends to be easy to prevent the crosslinking points from becoming dense. The epoxy equivalent can be measured, for example, according to JIS K7236:2001.

[0088] 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.

[0089] The content of the trifunctional amine-type epoxy resin is, for example, 1 to 15 mass%, 2 to 12 mass%, or 3 to 10 mass% based on the mass of the (A) resin. 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 3 to 8 mass%, or 3 to 5 mass%.

[0090] (4-functional amine-type epoxy resin) The tetrafunctional amine type epoxy resin may have, for example, a monoglycidylamino group, a diglycidylamino group, or both of these. 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).

[0091] [ka] (In the formula, R 2 represents a divalent organic group.

[0092] R 2 Examples of R include the groups exemplified in the description of X in the diisocyanate compound represented by the above formula (P3). 2 may be, for example, an alkylene group having 1 to 20 carbon atoms; an arylene group such as a phenylene group or 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 an organic group in which two of the arylene groups are bonded via a lower alkylene group having 1 to 5 carbon atoms, an oxy group (-O-), a carbonyl group (-CO-), or a sulfonyl group (-SO2-). 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 may be an unsubstituted phenylene group. The organic group may be an organic group in which two phenylene groups are bonded via a lower alkylene group having 1 to 5 carbon atoms, and may be a diphenylmethanediyl group (*-Ph-CH2-Ph-* (Ph is a phenylene group)).

[0093] 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 the 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 the adhesion due to the amine structure is easily obtained. When the epoxy equivalent is 90 g / eq or more, it tends to be easy to prevent the crosslinking points from becoming dense.

[0094] 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.

[0095] 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 15 mass%, 2 to 10 mass%, 5 to 10 mass%, or 3 to 8 mass% based on the mass of the (A) resin. When the content is within the above range, better detergent resistance is likely to be obtained.

[0096] 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, 4 to 28 mass%, 5 to 20 mass%, or 6 to 13 mass% based on the mass of the (A) resin.

[0097] From the viewpoint that better cleaning agent resistance tends to be obtained, the content of the trifunctional amine-type epoxy resin in the epoxy resin is, for example, 20 to 60 mass%, 25 to 50 mass%, or 30 to 40 mass% based on the total mass of the trifunctional amine-type epoxy resin and the tetrafunctional amine-type epoxy resin.

[0098] (any 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, a non-amine-type epoxy resin, etc. Examples of bifunctional 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 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 Dow Chemical Co., Ltd.), 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 Co., Ltd.), alicyclic epoxy resins (such as "ERL4234, 4299, 4299" manufactured by UCC Co., Ltd.), and the like. 221, 4206, etc.), epoxy resins having a dicyclopentadiene skeleton (DIC Corporation's "HP-7200" and "HP-7200H"), multifunctional epoxy resins (Mitsubishi Chemical Corporation's "Epon1031S", Chiba Specialty Chemicals' "Araldite 0163", Nagase ChemteX Corporation's "Denacol EX-611, EX-614, EX-614B, EX-622, EX-512, EX-521, EX-421, EX-411, EX-321", Daicel Corporation's "PB4700", "EHPE3150", Shin-Etsu Chemical Co., Ltd.'s "KR470", Resonaq's "BATG", Mitsubishi Chemical Corporation's "jER157S70, etc.) and the like.

[0099] 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 functional non-amine type epoxy resin.

[0100] 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 mass% or 5 to 18 mass% based on the mass of the (A) resin. 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 does not contain a non-amine type epoxy resin, or the content may be less than 5 mass%, less than 3 mass%, or less than 1 mass%.

[0101] From the viewpoint that better cleaning agent resistance tends to be obtained, the content of the trifunctional amine-type epoxy resin in the epoxy resin is, for example, 20 to 60 mass%, 25 to 50 mass%, or 30 to 40 mass% based on the total mass of the epoxy resin.

[0102] The total content of the epoxy resin contained in the thermosetting resin composition is, for example, 4 to 28 mass%, 5 to 20 mass%, or 6 to 13 mass% based on the mass of the (A) resin. When the content is within the above range, a flexible printed circuit board and an electronic component having good insulation reliability, low warpage, and weather resistance are easily obtained. When a trifunctional amine-type epoxy resin is contained in the epoxy resin, the total content of the epoxy resin contained in the thermosetting resin composition tends to be reduced. This makes it possible to suppress the inclusion of impurities derived from the epoxy resin in the thermosetting resin composition, and improve the insulation reliability of the flexible printed circuit board. Examples of impurities derived from the epoxy resin include chlorine derived from chlorine compounds that are raw materials for the epoxy resin.

[0103] For example, the thermosetting resin composition contains 1 to 15 mass% of a trifunctional amine-type epoxy resin based on the mass of the (A) resin. For example, the thermosetting resin composition contains 1 to 5 mass% of a trifunctional amine-type epoxy resin based on the mass of the (A) resin, and 5 to 10 mass% of a tetrafunctional amine-type epoxy resin based on the mass of the (A) resin.

[0104] [Organic solvents] 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], dimethylsulfoxide, 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).

[0105] The organic solvent may be any of the organic solvents listed as examples of organic solvents that can be used in the reaction between polyol and polyisocyanate. The organic solvent may be, for example, the same organic solvent as that used in the reaction between polyisocyanate A and tricarboxylic acid compound. The organic solvent may be γ-butyrolactone, particularly from the viewpoint of printability such as defoaming property and leveling property, and suppression of outflow (bleed) of the thermosetting resin composition between wirings.

[0106] The content of the organic solvent can be appropriately determined depending on the application of the thermosetting resin composition. For example, when applying 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.

[0107] [Optional components] The thermosetting resin composition may further contain, as necessary, a resin other than the (A) resin; a surfactant such as an antifoaming agent or a leveling agent; an organic filler; a colorant such as a dye or a pigment; a heat stabilizer, an antioxidant, a flame retardant, a lubricant, etc.

[0108] 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 the (A) resin.

[0109] [Manufacturing method] The method for producing the thermosetting resin composition is not particularly limited. For example, a method can be applied in which (A) resin, 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 kneading or mixer mixing, which is used in the production of ordinary paints, inks, and pastes. Each component can be added in order to the mixing vessel. Alternatively, a set for the thermosetting resin composition described later can be used, and the first and second agents can be added to the mixing vessel.

[0110] <Thermosetting resin composition set> In some embodiments, the set for thermosetting resin composition is used to obtain a thermosetting resin composition, and includes a first agent containing a resin (A) and a second agent containing an epoxy resin (D). By using the set for thermosetting resin composition, each component can be stably stored. The first agent, the second agent, or both of them may contain any component such as an inorganic filler, an ion trapping agent, an organic solvent, or an antifoaming agent. The set for thermosetting resin may be a set of two agents consisting of the first agent and the second agent, or a set of three or more agents further including one or more agents containing at least one component selected from the components (A) to (D), an organic solvent, a filler, an antifoaming agent, and the like.

[0111] <Cured product of thermosetting resin composition> In some embodiments, the cured product can be obtained using the thermosetting resin composition of the embodiment or the set for the thermosetting resin composition of the embodiment. Examples of the cured product include a cured film, a film, a sheet, and the like. The cured product such as a cured film, a film, a sheet, and the like may be a protective film. The cured product can be obtained, for example, by applying the thermosetting resin composition to a substrate, obtaining a coating film, and then thermally curing the coating film. The coating film may be dried before thermal curing. The cured product can 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.

[0112] Examples of the application method include spin coating, casting, dipping, dispensing, and printing methods such as letterpress printing, intaglio printing, offset printing, lithographic printing, letterpress 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.

[0113] <Flexible printed circuit boards and electronic components> 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, 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 printed wiring board and a flexible circuit board further including 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 embodiment.

[0114] 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.

[0115] The wiring pattern may be made 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 made of a material containing Sn, Ni, or Au.

[0116] 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.

[0117] The conditions for thermal curing are, from the viewpoints of preventing oxidation of the copper wiring 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 copper wiring and obtaining low warpage and flexibility suitable for a protective film, for example, 30 to 120 minutes, or 50 to 90 minutes.

[0118] In some embodiments, the thermosetting resin composition of the above embodiment is suitably used 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), TAB (Tape Automated Bonding), and CF (Chip On Film), as well as integrated circuits, semiconductor elements such as 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.

[0119] Examples of embodiments of the present invention are given below. The present invention is not limited to the following embodiments. (1) A thermosetting resin composition comprising: (A) a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group; (B) an ion trapping agent containing Zr, Mg, and Al; (C) an inorganic filler; and (D) an epoxy resin. (2) The thermosetting resin composition according to the above (1), wherein the content of the (B) ion trapping agent is 1 to 60 mass % based on the (A) resin. (3) The thermosetting resin composition according to the above (1), wherein the total content of the (B) ion trapping agent and the (C) inorganic filler is 10 to 70 mass % based on the (A) resin. (4) The thermosetting resin composition according to the above (1), wherein the (A) resin contains a polyamideimide having at least one group selected from the group consisting of an acid anhydride group and a carboxy group. (5) The thermosetting resin composition according to the above (4), wherein the polyamideimide contains a structure derived from the polycarbonate diol represented by the above formula (P1). (6) The thermosetting resin composition according to the above (4) or (5), wherein the polyamideimide contains a structure represented by the above formula (P2). (7) The thermosetting resin composition according to any one of (1) to (6) above, 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. (8) A method for obtaining a thermosetting resin composition according to any one of (1) to (7) above, A set for a thermosetting resin composition comprising a first part containing the resin and a second part containing the trifunctional amine-type epoxy resin. (9) A cured product obtained by using the thermosetting resin composition according to any one of (1) to (7) above or the set for a thermosetting resin composition according to (8) above. (10) A film obtained by using the thermosetting resin composition according to any one of (1) to (7) above or the set for a thermosetting resin composition according to (8) above. (11) A flexible printed circuit board obtained by using the thermosetting resin composition according to any one of (1) to (7) above or the set for a thermosetting resin composition according to (8) above. (12) An electronic part obtained by using the thermosetting resin composition according to any one of (1) to (7) above or the set for a thermosetting resin composition according to (8) above. EXAMPLES

[0120] The embodiments of the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited to the following examples.

[0121] <Synthesis of resin (A)> In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 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. pcontains 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. p The structure is derived from 1,6-hexanediol, and the average value n is in the range of 21.5 to 23.5.) 76.74g (0.04mol) was added. Furthermore, 59.37g (0.24mol) of 4,4'-diphenylmethane diisocyanate, 27.56g (0.16mol) of tolylene diisocyanate mixture (1) (mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in a mass ratio of 80:20), and 206.40g 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 reacted for 4 hours to produce a polyisocyanate having a urethane bond.

[0122] Next, the temperature of the resulting reaction liquid was lowered to 70°C, 55.76g (0.29mol) of trimellitic anhydride was added and completely dissolved, and then 13.86g (0.06mol) of 4,4'-diphenylmethane diisocyanate, 6.45g (0.04mol) of tolylene diisocyanate mixture (1) and 170.51g of γ-butyrolactone were added and stirred to obtain a mixture. The mixture was heated to 120°C to dissolve all the raw materials and reacted for 1 hour.

[0123] 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. Then, 5.36g (0.06mol) of 2-butanone oxime and 142.27g of γ-butyrolactone were added to terminate the reaction. A polyamideimide-containing solution having a urethane bond (solid content: 40.5% by mass, hereinafter referred to as "varnish") was obtained.

[0124] 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.

[0125] The conditions for GPC measurement of 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: Shimadzu Corporation "LC-20AD" Autosampler: Shimadzu Corporation "SIL-20A HT" Column oven: Shimadzu Corporation "CTO-20A" UV detector: Shimadzu Corporation "SPD-M20A" Columns: 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 10mg / THF 2.5mg Injection volume: 20μL Flow rate: 1mL / min Column temperature: 40℃ Molecular weight standard: Standard polystyrene (Tosoh Corporation: PStQuick B, PStQuick C, PStQuick D)

[0126] (Acid value) 1 g of polyamideimide was precisely weighed and placed in a stoppered flask, and 100 g of N-methylpyrrolidone was added to dissolve it. 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 potassium hydroxide aqueous solution until a brown color was observed, which lasted for 30 seconds. The inflection point on the titration curve was taken as the end point. A 25 mL burette manufactured by AS ONE Corporation was used as the titration device. The acid value was calculated from the amount of 0.1 mol / L potassium hydroxide aqueous solution required for titration using the following formula. Acid value = a x F x 5.611 / amount of polyamideimide (g) a: Amount of 0.1 mol / L potassium hydroxide solution (mL) F: Potency of 0.1 mol / L potassium hydroxide solution

[0127] <Preparation of Thermosetting Resin Composition> [Example 1] The polyamideimide varnish, ion trapping agent, inorganic filler, 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.

[0128] [Examples 2 to 4 and Comparative Examples 1 to 5] A thermosetting resin composition was obtained in the same manner as in Example 1, except that the components and amounts thereof were changed as shown in Table 1.

[0129] [Table 1]

[0130] The components used in the examples and comparative examples are listed below. (A) Resin: Polyamide-imide obtained in the synthesis example (B) Ion trapping agent IXEPLAS-A1: Particles containing Zr, Mg, and Al (average particle size 500 nm, manufactured by Toagosei Co., Ltd.) IXE100: Zr-based particles (average particle size 0.2-0.5 μm, manufactured by Toagosei Co., Ltd.) HT-1-NC: Hydrotalcite powder (average particle size 0.6 μm, manufactured by Sakai Chemical Industry Co., Ltd.) (C) Inorganic filler: Silica filler (average particle size 0.3 μm, SC1500-SXJ / Admatechs Co., Ltd.) (D) Epoxy resin YH-434L: 4-functional amine-modified epoxy resin (N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, epoxy equivalent 117g / eq, manufactured by Nippon Steel Chemical & Material Co., Ltd.) EP-3950S: Trifunctional amine modified epoxy resin (N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline, epoxy equivalent 95g / eq, manufactured by ADEKA Corporation) Defoamer: Acrylic defoamer (Disparlon LF-1983 / Kusumoto Chemicals Co., Ltd.) Solvent: γ-butyrolactone

[0131] <Evaluation> A flexible copper-clad laminate was produced using the thermosetting resin composition by the following method, and the insulation reliability, low warpage property, and cleaning agent resistance were evaluated. The evaluation results are shown in Table 1.

[0132] [Insulation reliability] (Fabrication of flexible copper-clad laminates) A flexible copper-clad laminate (copper wiring width / copper wiring interval width=10.0 μm / 10.0 μm) was prepared, which had a polyimide film (thickness 38 μm), a copper foil (sputtered copper, thickness 8 μm), and a comb-shaped copper wiring (wiring pattern) having a Sn plating 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 (dry film thickness 10 μm, length 3.5 mm, width 5.0 mm). The applied thermosetting resin composition was cured by heating at 23±3° C. for 10 minutes and then at 140° C. for 30 minutes to form a protective film. The laminate on which the protective film was formed was used as a test specimen. Schematic diagrams of the test specimen are shown in FIG. 1 and FIG. 2. FIG. 2 is an enlarged view of the area within the dashed line in FIG. 1. (Printing conditions) Printing machine: "LS-34GX" manufactured by Newlong Precision Industry Co., Ltd. Mesh plate: "3D250 mesh plate" made by Murakami Co., Ltd. Printing speed: 80mm / sec

[0133] (HAST (High Accelerated Stress Test) test) A voltage of 60 V was applied to the test piece in an atmosphere of 130°C and 85% relative humidity, and the time from the start of application until a short circuit occurred between the wiring was measured. 6The point at which the resistance was less than Ω was deemed to be the point at which a short circuit occurred between the wirings. The evaluation criteria were as follows: (Evaluation Criteria) A: The time from the start of application until a short circuit occurs between the wiring is 100 hours or more. B: The time from the start of application until a short circuit occurs between the wiring is less than 100 hours.

[0134] [Low warpage] (Fabrication of flexible copper-clad laminates) A flexible copper-clad laminate (length 48 mm, width 35 mm) was prepared, which had a polyimide film (thickness 38 μm), a copper foil (sputtered copper, thickness 8 μm), and a comb-shaped copper wiring (wiring pattern) having a Sn plating 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 (dry film thickness 10 μm, length 40.2 mm, width 22.9 mm). 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 on which the protective film was formed was used as a test piece. (Printing conditions) Printing machine: "LS-34GX" manufactured by Newlong Precision Industry Co., Ltd. Mesh plate: "SUS200 mesh plate" manufactured by Murakami Co., Ltd. Printing speed: 80mm / sec

[0135] (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 platen with the protective film side facing down, and the distance (mm) from the platen to the apex of the warp of the flexible copper-clad wiring board was measured and taken as the warp height. The evaluation criteria were as follows: (Evaluation Criteria) A: Warpage height is less than 6 mm B: Warpage height is 6mm or more

[0136] [Resistance to cleaning agents] (Fabrication of flexible copper-clad laminates) A flexible copper-clad laminate (copper wiring width / copper wiring interval width=10.0 μm / 10.0 μm) was prepared, which had a polyimide film (thickness 38 μm), a copper foil (sputtered copper, thickness 8 μm), and a comb-shaped copper wiring (wiring pattern) having a Sn plating 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 (dry film thickness 10 μm, length 3.5 mm, width 5.0 mm). The applied thermosetting resin composition was cured by heating at 120° C. for 3 minutes and then at 120° C. for 1 hour to form a protective film. The laminate with the protective film formed was used as a test piece. Schematic diagrams of the test piece are shown in FIG. 1 and FIG. 2. FIG. 2 is an enlarged view of the area within the dashed line in FIG. 1. In FIG. 1 and FIG. 2, 1 is a polyimide film, 2 is a wiring pattern, 3 is a protective film, and 100 is a test piece. (Printing conditions) Printing machine: "LS-34GX" manufactured by Newlong Precision Industry Co., Ltd. Mesh plate: "3D250 mesh plate" made by Murakami Co., Ltd. Printing speed: 80mm / sec

[0137] (Evaluation of detergent resistance) A hollow cylindrical plastic (inner diameter 7 mm) was attached to the 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. 1 mL of glass cleaner (WindexSC, manufactured by Johnson, containing water, alcohol, alkanolamine, surfactant, etc.) was added inside 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 is a polyimide film, 2 is a wiring pattern, 3 is a protective film, 11 is a hollow cylindrical plastic, 12 is a glass cleaner, 13 is a cover film, and 100 is a test specimen. A voltage of 80 V was applied to the test piece in an atmosphere of 23°C and 60% relative humidity, and the time from the start of application until a short circuit occurred between the wires was measured. 6The point at which the resistance was less than Ω was deemed to be the point at which a short circuit occurred between the wirings. The evaluation criteria were as follows: (Evaluation Criteria) A: The time from the start of application until a short circuit occurs between the wiring is 40 hours or more. B: The time from the start of application until a short circuit occurs between the wiring is less than 40 hours. [Explanation of symbols]

[0138] 1 Polyimide film 2. Wiring Pattern 3 Protective film 11 Hollow cylindrical plastic 12. Glass cleaner 13 Cover film 100 test pieces

Claims

1. A thermosetting resin composition comprising: (A) a resin having at least one group selected from the group consisting of an acid anhydride group and a carboxy group; (B) an ion trapping agent containing Zr, Mg, and Al; (C) an inorganic filler; and (D) an epoxy resin.

2. The thermosetting resin composition according to claim 1, wherein the content of the ion trapping agent (B) is 1 to 60 mass % based on the resin (A).

3. The thermosetting resin composition according to claim 1, wherein a total content of the ion trapping agent (B) and the inorganic filler (C) is 10 to 70 mass% based on the resin (A).

4. 2. The thermosetting resin composition according to claim 1, wherein the resin (A) comprises a polyamideimide having at least one group selected from the group consisting of an acid anhydride group and a carboxy group.

5. The thermosetting resin composition according to claim 4, wherein the polyamideimide contains a structure derived from a polycarbonate diol represented by the following formula (P1): 【Chemistry 1】 (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.)

6. The thermosetting resin composition according to claim 4 , wherein the polyamideimide comprises a structure represented by the following formula (P2): 【Chemistry 2】 (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.)

7. 2. The thermosetting resin composition according to claim 1, 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.

8. A method for obtaining the thermosetting resin composition according to any one of claims 1 to 7, A set for a thermosetting resin composition comprising a first agent containing the resin and a second agent containing the trifunctional amine-type epoxy resin.

9. A cured product obtained by using the thermosetting resin composition according to any one of claims 1 to 7.

10. A film obtained by using the thermosetting resin composition according to any one of claims 1 to 7.

11. A flexible printed circuit board obtained by using the thermosetting resin composition according to any one of claims 1 to 7.

12. An electronic part obtained by using the thermosetting resin composition according to any one of claims 1 to 7.

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