TW201843050A - Curable resin composition, laminate structure, cured product thereof, and electronic component capable of satisfying required performance of both solder resist and coverlay, and ensuring excellent heat resistance and low rebound properties - Google Patents

Abstract

The object of the present invention is to provide a curable resin composition which satisfies required performance of both solder resist and coverlay, ensures excellent heat resistance and low rebound properties without deteriorating developability, and has less bending after heated. In addition, the present invention further provides a curable resin composition which satisfies required performance of both solder resist and coverlay and ensures excellent developability (alkali solubility) and heat resistance (solder heat resistance). The solution of the present invention is a curable resin composition which contains an alkali soluble polyimide resin, an alkali soluble resin other than the polyimide resin, and a curable compound.

Description

Curable resin composition, laminated structure, cured product thereof, and electronic component

The present invention relates to a curable resin composition (hereinafter also simply referred to as a "composition"), a laminated structure, a cured product thereof, and an electronic component that are useful as an insulating film for electronic parts such as flexible printed wiring boards.

In recent years, as electronic devices have become smaller and thinner due to the spread of smartphones and tablet terminals, there has been a demand for smaller electronic components such as circuit boards. Therefore, the use of a flexible printed wiring board that can be folded and stored is expanding, and even for a flexible printed wiring board, it is required to have a higher reliability than before.

For this reason, as an insulating film for ensuring the insulation reliability of a flexible printed wiring board, a bent portion (curved portion) is currently used as a polymer film having excellent mechanical properties such as heat resistance and bendability. The imide is used as a base cover film (for example, refer to Patent Documents 1 and 2), and the mounting portion (non-bent portion) is a mixing process using a photosensitive resin composition that is excellent in electrical insulation or solder heat resistance and can be finely processed. .

That is, a cover film using polyimide as a base is not suitable for fine wiring because it needs to be processed by die cutting. Therefore, it is necessary to partially use an alkali-developing photosensitive resin composition (solder resist) that can be processed by photolithography for a wafer mounting portion that requires fine wiring. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 62-263692 [Patent Document 2] Japanese Patent Laid-Open No. 63-110224

[Problems to be Solved by the Invention]

As such, in the conventional manufacturing steps of flexible printed wiring boards, a mixed process of a step of attaching a cover film and a step of forming a solder resist has to be adopted, and there are problems such as poor cost and workability. .

In this regard, research has hitherto been conducted to apply an insulating film as a solder resist or an insulating film as a cover film to a solder resist and a cover film for a flexible printed wiring board. However, the requirements for reducing the space of a circuit board can be fully satisfied. Materials that require performance for both solder resist and cover film have not yet been put into practical use.

In addition, the solder resist or the cover film is required to be excellent in developability (alkali solubility) or heat resistance (solder heat resistance), low resilience (rebound resilience), and warpage after heating (warpage after hardening) is relatively low. Small and other characteristics. However, in order to ensure heat resistance and to improve low resilience or warpage after heating, when an alkali-soluble resin having a large molecular weight is used, problems such as failure to develop may occur. In addition, although fluorene-based resins have heat resistance, they have disadvantages such as large warpage after curing. Urethane-based resins have low resilience and low warpage resins. However, there are problems such as poor heat resistance. Therefore, the use of various resin compositions proposed in the past cannot satisfy all requirements such that the developability is not impaired, the heat resistance and the low resilience are excellent, and the warpage after heating is small.

Therefore, the main object of the present invention is to provide a curable resin composition that satisfies the required performance of both a solder resist and a cover film, does not impair the developability, is excellent in heat resistance or low resilience, and has less warpage after heating. . Another object of the present invention is to provide a curable resin suitable for an insulating film such as a flexible printed wiring board (especially, a one-time forming process of a bent portion (curved portion) and a mounting portion (non-curved portion)). A composition, a laminated structure, a cured product thereof, and an electronic component such as a flexible printed wiring board having the cured product as a protective layer such as a cover film or a solder resist. [Means for solving problems]

As a result of intensive research in order to solve the above-mentioned problems, the present inventors have further completed the present invention having the following contents as the gist. That is, the curable resin composition of the present invention is characterized by containing an alkali-soluble polyimide resin, an alkali-soluble resin other than the polyimide resin, and a curable compound.

In the curable resin composition of the present invention, the alkali-soluble resin other than the polyimide resin is preferably a polyimide resin, and the polyimide resin is as follows The polyamidamine / imide resin having the structure represented by the general formula (1) and the structure represented by the following general formula (2) is preferable. (X ₁ is a residue of an aliphatic diamine (a) derived from a dimer acid having 24 to 48 carbons, X ₂ is a residue of an aromatic diamine (b) having a carboxyl group, and Y is independently a ring Hexane ring or aromatic ring).

The curable resin composition of the present invention preferably further contains core-shell rubber particles. Furthermore, in the curable resin composition of the present invention, the polyfluorene imine resin is preferably one having a carboxyl group, and more preferably one having a carboxyl group and a phenolic hydroxyl group.

Furthermore, in the curable resin composition of the present invention, the curable compound is preferably an epoxy resin.

The laminated structure of the present invention includes a resin layer (A) and a resin layer (B) laminated on a substrate through the resin layer (A), wherein the resin layer (B ) Is made of the curable resin composition, and the resin layer (A) is made of an alkali-developing resin composition containing an alkali-soluble resin and a heat-reactive compound.

Moreover, the hardened | cured material of this invention is characterized by the said curable resin composition or the said laminated structure.

Furthermore, the electronic component of the present invention is characterized by having an insulating film made of the hardened material.

Here, as the electronic component of the present invention, for example, a layer having the above-mentioned laminated structure formed on a flexible printed wiring board, patterning by light irradiation, and a pattern using a developing solution at a time can be cited. The formed insulating film. Alternatively, a resin layer (A) and a resin layer (B) may be sequentially formed on a flexible printed wiring board without using the above-mentioned laminated structure, and then patterned by light irradiation and used. The developer is an insulating film in which the pattern is formed at one time. In the present invention, the "pattern" means a pattern-shaped hardened material, that is, an insulating film. [Effect of the invention]

According to the present invention, it is possible to provide a curable resin composition that satisfies the required performance of both a solder resist and a cover film, does not impair the developability, is excellent in heat resistance or low resilience, and has less warpage after heating. In addition, a hardening resin composition capable of realizing an insulating film suitable for electronic parts such as flexible printed wiring boards (in particular, a one-time forming process of a bent portion (curved portion) and a mounted portion (non-curved portion)) Materials, laminated structures, hardened materials thereof, and electronic components such as flexible printed wiring boards having the hardened materials as a protective film such as a cover film or a solder resist.

[Best Mode for Implementing Invention]

Hereinafter, embodiments of the present invention will be described in detail. (Curable resin composition) The curable resin composition of the present invention contains an alkali-soluble polyimide resin, other alkali-soluble resins, and a curable compound. By containing an alkali-soluble polyimide resin, other alkali-soluble resins, and hardening compounds, it can meet the required performance of both solder resists and cover films, and achieve developability or heat resistance. It is an excellent curable resin composition.

(Alkali-soluble polyfluorene imine resin) As the alkali-soluble polyfluorene imide resin, as long as it contains one or more functional groups of a phenolic hydroxyl group and a carboxyl group and can be developed using an alkaline solution, it can be used. Known idiomatic.

With this polyfluorene imide resin, characteristics such as bending resistance and heat resistance become more excellent.

Examples of such alkali-soluble polyfluorene imine resins include resins obtained by reacting a carboxylic acid anhydride component with an amine component and / or an isocyanate component. Here, the alkali-soluble group is introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. In addition, the fluorene imidization system can be performed by thermal hydration, chemical fluorene imidization, or a combination of these.

Examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride, tricarboxylic acid anhydride, and the like, but are not limited to these acid anhydrides, as long as they are compounds having an acid anhydride group and a carboxyl group that react with an amine group or an isocyanate group, they may include the same Derivatives to use. These carboxylic anhydride components can be used alone or in combination.

Examples of the amine component include diamines such as aliphatic diamines and aromatic diamines, polyamines such as aliphatic polyetheramines, diamines having a carboxyl group, and diamines having a phenolic hydroxyl group. The amine component is not limited to such an amine, but it must be an amine using a functional group capable of introducing at least one of a phenolic hydroxyl group and a carboxyl group. These amine components may be used alone or in combination.

As the isocyanate component, aromatic diisocyanate and its isomers or polymers, aliphatic diisocyanates, alicyclic diisocyanates and its isomers, or other widely used diisocyanates, may be used. It is not limited to these isocyanates. These isocyanate components can be used alone or in combination.

For the synthesis of such an alkali-soluble polyfluorene imide resin, a well-known organic solvent can be used. As such an organic solvent, there is no problem as long as it is a solvent which does not react with carboxylic anhydrides, amines, and isocyanates of the raw materials, and which can dissolve these raw materials, and the structure is not particularly limited. In particular, since the solubility of the raw materials is high, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylimide Aprotic solvents such as osmium and γ-butyrolactone are preferred.

As described above, the alkali-soluble polyimide resin balances the alkali solubility (developing properties) of the polyimide resin with the mechanical properties of the cured product of the polyimide resin-containing resin composition. From the viewpoint of other characteristics, the acid value (solid acid value) is preferably 20 to 200 mgKOH / g, and more suitably 60 to 150 mgKOH / g. Specifically, since the acid value is 20 mgKOH / g or more, alkali solubility (that is, developability) becomes good, and further, the crosslinking density with the thermosetting component after light irradiation becomes high, so A sufficient development contrast value can be obtained. In addition, by setting the acid value to 200 mgKOH / g or less, the so-called thermal atomization in the PEB (POST EXPOSURE BAKE) step after light irradiation described below can be suppressed, thereby increasing the process margin.

In addition, when considering the molecular weight of such an alkali-soluble polyimide resin, considering the developability and the characteristics of the cured coating film, the mass average molecular weight Mw is preferably 100,000 or less, more preferably 1,000 to 100,000, and 2,000 ~ 50,000 is better. When the molecular weight is 100,000 or less, the alkali solubility of the unexposed portion is increased, and the developability is improved. On the other hand, when the molecular weight is 1,000 or more, sufficient exposure resistance and hardened properties can be obtained in the exposed portion after the exposure and PEB steps.

(Alkali-soluble resins other than polyimide resins) As such an alkali-soluble resin, any resin that contains one or more functional groups of a phenolic hydroxyl group and a carboxyl group and can be developed using an alkali solution, Well-known accustomers can be used. For example, a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin that has been conventionally used in solder resists can be used.

In particular, an alkali-soluble polyamidamine / imide resin can be suitably used from the viewpoint of obtaining a resin composition which does not impair the developability and which has more excellent properties such as bending resistance and heat resistance. By using such an alkali-soluble polyamidoimide resin in combination with the aforementioned alkali-soluble polyamidoimide resin, it is possible to provide excellent heat resistance or low resilience without sacrificing developability and low Curable resin composition having a small dielectric and warpage after heating.

Here, as a blending ratio of the alkali-soluble polyamidoimine resin and the aforementioned alkali-soluble polyamidoimide resin, the mass ratio can be set to 98: 2 to 50:50, and 90:10. ~ 50: 50 is better.

(Alkali-soluble polyamidoamine imine resin) 物 中 In the curable resin composition of the present invention, as the alkali-soluble polyamidoamine imine resin, as long as it contains one or more functional groups of a phenolic hydroxyl group and a carboxyl group It can be developed by using an alkali solution, and a well-known person can be used. Such an alkali-soluble polyamidofluorene imine resin may be, for example, a resin obtained by reacting a carboxylic acid anhydride component with an amine component to obtain a fluorimidate, and then reacting the obtained fluorimidate with an isocyanate component. Wait. Here, the alkali-soluble group is introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. In addition, the fluorene imidization system can be performed by thermal hydration, chemical fluorene imidization, or a combination of these.

Examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride, tricarboxylic acid anhydride, and the like, but are not limited to these acid anhydrides, as long as they are compounds having an acid anhydride group and a carboxyl group that react with an amine group or an isocyanate group, they may include the Derivatives to use. These carboxylic anhydride components can be used alone or in combination.

Examples of the amine component include diamines such as aliphatic diamines and aromatic diamines, polyamines such as aliphatic polyetheramines, diamines having a carboxyl group, and diamines having a phenolic hydroxyl group. The amine component is not limited to such an amine, but it must be an amine using a functional group capable of introducing at least one of a phenolic hydroxyl group and a carboxyl group. These amine components may be used alone or in combination.

As the isocyanate component, aromatic diisocyanate and its isomers or polymers, aliphatic diisocyanates, alicyclic diisocyanates and its isomers, or other widely used diisocyanates, may be used. It is not limited to these isocyanates. These isocyanate components can be used alone or in combination.

As described above, the alkali-soluble polyamidoimide resin has a good balance between the alkali solubility (developing properties) of the polyamidoimide resin and the resin composition containing the polyamidoimide resin. From the viewpoint of other characteristics such as mechanical properties of the hardened material, the acid value (solid acid value) is preferably 30 mgKOH / g or more, and more preferably 30 mgKOH / g to 150 mgKOH / g. It is particularly preferable to set it to 50 mgKOH / g to 120 mgKOH / g. Specifically, since the acid value is 30 mgKOH / g or more, alkali solubility (that is, developability) becomes good, and further, the crosslinking density with the thermosetting component after light irradiation becomes high, so A sufficient development contrast value can be obtained. In addition, by setting the acid value to 150 mgKOH / g or less, the so-called thermal atomization in the PEB (POST EXPOSURE BAKE) step after light irradiation described below can be suppressed, thereby increasing the process margin.

The molecular weight of the alkali-soluble polyamidamine / imine resin is preferably 20,000 or less, more preferably 1,000 to 15,000, and more preferably 2,000 to 10,000 when considering the developability and the characteristics of the cured coating film. For the better. When the molecular weight is 20,000 or less, the alkali solubility of the unexposed portion is increased, and the developability is improved. On the other hand, when the molecular weight is 1,000 or more, sufficient exposure resistance and hardened properties can be obtained in the exposed portion after the exposure and PEB steps.

In particular, in the present invention, in order to further improve the developability, a polyamidamine / imine resin having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) is used. Is better.

Here, X ₁ is a residue of an aliphatic diamine (a) (also referred to as "dimerdiamine (a)" in this specification) derived from a dimer acid having 24 to 48 carbon atoms. . X ₂ is a residue of an aromatic diamine (b) having a carboxyl group (also referred to as a "carboxyl-containing diamine (b)" in the present specification). The Y systems are each independently a cyclohexane ring or an aromatic ring.

By including the structure represented by the general formula (1) and the structure represented by the general formula (2), it is possible to dissolve an alkali that can be dissolved even by using a mild alkali solution such as a 1.0% by mass sodium carbonate aqueous solution. Polyimide resin is excellent in properties. Moreover, the hardened | cured material of the resin composition containing such a polyamidoamine imine resin can have the outstanding dielectric characteristic.

Dimer diamine (a) can be obtained by reductive amination of a carboxyl group in a dimer of an aliphatic unsaturated carboxylic acid having 12 to 24 carbon atoms. That is, the dimer diamine (a) of an aliphatic diamine derived from a dimer acid can be polymerized with, for example, an unsaturated fatty acid such as oleic acid and linoleic acid to form a dimer acid. After reduction, it is obtained by amination. As such an aliphatic diamine, commercially available products, such as PRIAMINE 1073, 1074, and 1075 (made by Croda Japan Co., Ltd.), which have a diamine of 36 carbon skeletons, can be used. The dimer diamine (a) is preferably a dimer acid derived from a carbon number of 28 to 44, and a dimer acid derived from a carbon number of 32 to 40 is more preferable.

Specific examples of the carboxyl group-containing diamine (b) include 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, and 5,5'-methylenebis (anthranilide). ), Benzidine-3,3'-dicarboxylic acid, etc. The carboxyl group-containing diamine (b) may be composed of one type of compound or a plurality of types of compounds. From the viewpoint of raw material availability, the diamine (b) containing a carboxyl group is preferably a compound containing 3,5-diaminobenzoic acid and 5,5'-methylenebis (anthranilic acid).

In the polyamidamine / imine resin, the relationship between the content of the structure represented by the general formula (1) and the content of the structure represented by the general formula (2) is not limited. The dimer diamine (from the viewpoint of a good balance between the alkali solubility of the polyamidoimide resin and the other characteristics such as the mechanical properties of the cured product of the resin composition containing the polyamidoimide resin) The content of a) (unit: mass%) is preferably 20 to 60 mass%, and more preferably 30 to 50 mass%. In the present specification, the "content of the dimer diamine (a)" means that the content of the diamine diimide resin relative to the quality of the polyimide diimide resin produced is positioned as the content of the polyimide diimide resin. Ratio of the feed amount of the dimer diamine (a), which is one of the raw materials. Here, "the quality of the polyimide resin produced" means that the amount of the polyimide resin produced by the polyimide resin is subtracted from the feed amount of all the raw materials used to produce the polyimide resin. Value after theoretical amount of water (H ₂ O) and carbonic acid gas (CO ₂ ) generated by amidation.

From the viewpoint of improving the alkali solubility of the polyamidofluorine imine resin, it is preferable that the portion represented by Y in the general formula (1) and the general formula (2) has a cyclohexane ring. From the viewpoint of a good balance between the alkali solubility of the polyamide-imide resin and other characteristics such as the mechanical properties of the cured product of the resin composition containing the polyamide-imide resin, Y is represented by the above-mentioned Y. The relationship between the amount of aromatic rings and the amount of cyclohexane rings in the part is preferably 85/15 to 100/0, and 90/10 is the molar ratio of the content of aromatic rings to the content of cyclohexane rings. ~ 99/1 is more preferred, and 90/10 ~ 98/2 is more preferred.

The polyamidamine / imide resin may further have a partial structure represented by the following general formula (i). Here, X ₃ is a residue of a diamine (f) other than the dimer diamine (a) and the carboxyl group-containing diamine (b) (also referred to as "other diamine (f)" in this specification). ; Y is independently an aromatic ring or a cyclohexane ring, as in the general formula (1) and the general formula (2). The other diamine (f) system may be composed of one type of compound, or may be composed of a plurality of types of compounds.

Specific examples of the other diamine (f) include 2,2-bis [4- (4-aminophenoxy) phenyl] propane, and bis [4- (3-aminophenoxy) Phenyl] fluorene, bis [4- (4-aminophenoxy) phenyl] fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4 -(4-aminophenoxy) phenyl] methane, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether , Bis [4- (4-aminophenoxy) phenyl] ketone, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene , 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-bis (trifluoromethyl) biphenyl-4,4'-diamine, 2,6,2 ', 6'-tetramethyl-4,4'-diamine, 5,5'-dimethyl-2,2'-sulfofluorenyl-biphenyl-4,4'-diamine, 3,3'-diamine Hydroxybiphenyl-4,4'-diamine, (4,4'-diamino) diphenyl ether, (4,4'-diamino) diphenylphosphonium, (4,4'-diamine) Group) benzophenone, (3,3'-diamino) benzophenone, (4,4'-diamino) diphenylmethane, (4,4'-diamino) diphenyl Examples of aromatic diamines such as ethers and (3,3'-diamino) diphenyl ethers include hexamethylenediamine, octamethylenediamine, decamethylenediamine, and dodecamidine A Fatty substances such as methylenediamine, stearylmethylenediamine, 4,4'-methylenebis (cyclohexylamine), isophoronediamine, 1,4-cyclohexanediamine, norbornenediamine Group of diamines.

The polyamidamine / imine resin system may have a structure represented by the following general formula (ii).

Here, Z may be an aliphatic group or an aromatic group. In the case of an aliphatic group, an alicyclic group such as a cyclohexane ring may be included. According to the manufacturing method mentioned later, Z system becomes a residue of a diisocyanate compound (e).

The method for producing the polyamidofluorene imine resin is not limited, and it can be produced through a polyamidoimidization step and a polyamidoamine imidization step using a well-known and commonly used method.

醯 In the imidization step, a dimer diamine (a), a carboxyl group-containing diamine (b), and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) By reacting with one or two selected from the group consisting of trimellitic anhydride (d), a sulfonium imide is obtained.

The feed amount of the dimer diamine (a) is preferably an amount in which the content of the dimer diamine (a) is 20 to 60% by mass, and the content of the dimer diamine (a) is 30 to An amount of 50% by mass is more preferable. The content of the dimer diamine (a) is defined as described above.

If necessary, other diamines (f) may be used simultaneously with the dimer diamine (a) and the carboxyl group-containing diamine (b).

From the viewpoint of improving the alkali solubility of the polyamidofluorine imine resin, the use of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) in the fluorene imidization step is preferred. good. The amount of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) is preferably 85/15 to 100 / in terms of molar ratios relative to the amount of trimellitic anhydride (d) used. 0, more preferably 90/10 ~ 99/1, more preferably 90/10 ~ 98/2.

The diamine compound (B) used to obtain the amidine imide (A) (specifically, it means a dimer diamine (a) and a carboxyl group-containing diamine (b), and others used as required The amount of diamine (f)) and acid anhydride (C) (specifically, it means that cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) and trimellitic anhydride (d) There is no limitation on the relationship between the amount of one or two selected from the group. The amount of the acid anhydride (C) used is preferably 2.0 or more and 2.4 or less based on the molar ratio of the diamine compound (B), and the amount of 2.0 or more and 2.2 or less based on the molar ratio good.

In the fluorenimidine imidization step, the fluorenimide (A) obtained in the fluorenimidization step described above is reacted with a diisocyanate compound (e) to obtain a compound having the following general formula ( 3) Polyamidamine / imine resin having a structure represented by the above.

The specific type of the diisocyanate compound (e) is not limited. The diisocyanate compound (e) may be composed of one type of compound, or may be composed of a plurality of types of compounds.

Specific examples of the diisocyanate compound (e) include 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and naphthalene-1,5-diisocyanate. , O-xylene diisocyanate, m-xylene diisocyanate, 2,4-toluene dimer and other aromatic diisocyanates; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexyl Aliphatic diisocyanates such as methane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and the like. The diisocyanate compound (e) preferably contains an aliphatic isocyanate from the viewpoint that both the alkali solubility of the polyamidoimine resin and the light transmittance of the polyamidoimide resin are good. The diisocyanate compound (e) is preferably an aliphatic isocyanate.

The amount of the diisocyanate compound (e) used in the amidation process is not limited. From the viewpoint of imparting a moderate alkali solubility to the polyamidofluorine imine resin, the amount of the diisocyanate compound (e) used is larger than that of the diamine compound (e) used to obtain the polyimide compound (A) ( The amount of B) is more preferably 0.3 or more and 1.0 or less in terms of mole ratios, more preferably 0.4 or more and 0.95 or less, and particularly preferably 0.50 or more and 0.90 or less.

The polyamidamine / imide resin produced in this manner includes a substance having a structure represented by the following general formula (3).

In the general formula (3), X is independently a diamine residue (residue of the diamine compound (B)), Y is independently an aromatic ring or a cyclohexane ring, and Z is a diisocyanate compound (e). Residues. n is a natural number.

(Sclerosing Compound) The curable resin composition of the present invention further contains a curing compound. As the curable compound, a conventionally known compound having a functional group capable of undergoing a curing reaction by heat or light can be used. Examples include thermosetting compounds having a functional group capable of performing a hardening reaction by heat, such as a cyclic (thio) ether group, and those having a functional group capable of undergoing a hardening reaction by light, such as an ethylenically unsaturated double bond group. Among the photocurable compounds having a functional group, a thermosetting compound is particularly preferred, and an epoxy resin is preferably used. Examples of the epoxy resin include bisphenol A epoxy resin, brominated epoxy resin, novolac epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and glycidylamine. Type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenyl type epoxy resin or a mixture thereof; double Phenolic S type epoxy resin, bisphenol A novolac type epoxy resin, heterocyclic epoxy resin, biphenol novolac type epoxy resin, naphthyl group-containing epoxy resin, epoxy resin having a dicyclopentadiene skeleton Resin, etc.

When using a thermosetting compound in particular, the equivalent ratio of such a thermosetting compound to an alkali-soluble resin (polyimide resin, polyimide resin, etc.) (alkali solubility of a carboxyl group, etc.) Group: a thermosetting group such as an epoxy group) is preferably prepared at a ratio of 1: 0.1 to 1:10. By setting such a blending ratio, the developability is good, and a fine pattern can be easily formed. The above equivalent ratio is preferably 1: 0.2 to 1: 5.

(Core-shell rubber particles) 硬化 The curable resin composition of the present invention preferably further contains core-shell rubber particles. Accordingly, it is possible to provide a curable resin composition which is excellent in developability or heat resistance and is suitable for use as an insulating film of electronic parts such as flexible printed wiring boards. For example, it can satisfy solder resists and coatings. Both of the films require performance.

The core-shell rubber particles constituting the curable resin composition of the present invention have the following functions: the core-shell rubber particles are used to improve flexibility without reducing adhesion. The core-shell rubber particles refer to a rubber material having a multilayer structure composed of a core layer having a different composition from each other, and one or more shell layers covering the core layer. As will be described later, the core-shell rubber particles are composed of a core layer made of a material having excellent flexibility, and a shell layer made of a material having excellent affinity with other components. At the same time, the lower the elastic modulus, the dispersibility is also good. With the combination of the features of the present invention in which such core-shell rubber particles are blended, it is possible to provide excellent performance without cracks and the like during excessive bending tests even in a heat treatment such as reflow. In this way, the flexible hardened material can exhibit a unique effect which is not provided by the conventional technology.

As a constituent material of the core layer, a material having excellent flexibility can be used. Specific examples thereof include a silicone elastomer, a butadiene elastomer, a styrene elastomer, an acrylic elastomer, a polyolefin elastomer, a silicone / acrylic composite elastomer, and the like.

On the other hand, as a constituent material of the shell layer, a material having excellent affinity for other components can be used. For example, when the curable resin composition contains an epoxy resin, it is preferable to use core-shell rubber particles having a shell layer made of a material having excellent affinity for epoxy resin. Also preferred are acrylic resins and epoxy resins.

From the viewpoint of storage stability, it is preferable that such core-shell rubber particles have a hardening reactive group on the surface. As such a hardening reactive group, it may be a thermosetting reactive group or a photohardening group. Sex reactive group. The core-shell rubber particles may have two or more types of curable reactive groups.

Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an imine group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, and an ethoxymethyl group. Group, ethoxyethyl, oxazoline and the like. It is also preferably an epoxy group.

Examples of the photocurable reactive group include a vinyl group, a styryl group, a methacryl group, and acryl group. Even in the case where the filler content is large, since the reactivity is appropriate, methacrylfluorenyl and acrylfluorenyl are preferable.

Here, the method of introducing a hardenable reactive group into the surface of the core-shell rubber particles is not particularly limited, and a well-known and commonly used method can be used. For example, when a shell layer is formed around the core layer, the constituent material of the shell layer can be introduced by polymerizing a material having a hardenable reactive group different from a functional group used for the polymerization reaction with the core layer. To the core layer.

Examples of commercially available core-shell rubber particles include Paraloid ELX2655 manufactured by Rohm and Haas Corporation, XER-91 manufactured by Japan Synthetic Rubber Corporation, and the like.

In the curable resin composition of the present invention, since the crack resistance is excellent, the average particle diameter of the core-shell rubber particles is preferably 2 μm or less. It is more preferably 0.01 to 1 μm. In this specification, the average particle diameter refers to a value of D 50 measured using a Microtrac particle size analyzer manufactured by Nikkiso Co., Ltd.

In the curable resin composition of the present invention, the content of the core-shell rubber particles is preferably 1 to 30% by mass per unit organic component in the solid content of the composition. When it is 1% by mass or more, it is preferable that the crack resistance is excellent. On the other hand, when it is 30% by mass or less, it is preferable in terms of excellent printability and developability. It is more preferably 3 to 20% by mass. The curable resin composition of the present invention may contain core-shell rubber particles having a curable reactive group and non-core-shell rubber particles. Note that the organic component referred to herein means all solid components other than inorganic components such as fillers.

(Photopolymerization initiator) 若 In the case of the photosensitive resin composition of the curable resin composition of the present invention, it is preferable to further include a photopolymerization initiator. As the photopolymerization initiator, a well-known user can be used. In particular, when the curable resin composition of the present invention is applied to a PEB step after light irradiation described later, a photopolymerization agent is also used. Functional photopolymerization initiators are suitable. In this PEB step, a photopolymerization initiator and a photobase generator can be used together.

A photopolymerization initiator that also has a function as a photobase generator is to change the molecular structure by irradiation with light such as ultraviolet rays or visible light, or to break down the molecules to produce a hardening compound (that is, heat). A compound of one or more basic substances that function as a catalyst for the polymerization reaction of the curable compound). Examples of the basic substance include a secondary amine and a tertiary amine. Examples of such a photopolymerization initiator that also has a function of a photobase generator include, for example, an α-aminoacetophenone compound, an oxime ester compound, or an alkoxyimine group and an N-formamylated aromatic compound. Compounds of substituents such as a family amine group, an N-fluorinated aromatic amine group, a nitrobenzylcarbamate group, an alkoxybenzylcarbamate group, and the like. Among these, an oxime ester compound and an α-aminoacetophenone compound are preferred, and an oxime ester compound is further preferred. The α-aminoacetophenone compound is particularly preferably one having two or more nitrogen atoms.

As long as the α-aminoacetophenone compound has a benzoin ether bond in the molecule, and when it is irradiated with light, it will cause cleavage in the molecule to generate a basic substance (amine) that functions as a hardening catalyst.

The oxime ester compound may be any compound as long as it generates a basic substance upon irradiation with light.

Such a photopolymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photopolymerization initiator in the resin composition is preferably 0.1 to 40 parts by mass, and more preferably 0.3 to 15 parts by mass with respect to 100 parts by mass of the total amount of the alkali-soluble resin. When it is 0.1 mass parts or more, the contrast value of the development resistance of a light irradiation part / non-irradiation part can be obtained favorably. Moreover, when it is 40 mass parts or less, hardened | cured material characteristics will improve.

In the curable resin composition of the present invention, the following components can be further blended as necessary.

(Polymer resin) 硬化 The curable resin composition of the present invention can be blended with a well-known polymer resin for the purpose of improving the flexibility and touch-dryness of the obtained cured product. Examples of such polymer resins include cellulose-based, polyester-based, phenoxy resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamine-based, and polyamine.醯 imine-based adhesive polymers, elastomers, etc. Such polymer resins can be used alone or in combination of two or more.

(Inorganic Filler) 硬化 The curable resin composition of the present invention may contain an inorganic filler in order to suppress the hardening shrinkage of the cured product and improve properties such as adhesion and hardness. Examples of such an inorganic filler include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and nitride. Silicon, aluminum nitride, boron nitride, Neuberger diatomaceous earth, etc.

(Colorant) 硬化 The curable resin composition of the present invention can be blended with well-known and conventional colorants such as red, orange, blue, green, yellow, white, and black. As such a coloring agent, any of pigments, dyes, and pigments may be used.

(Organic Solvent) The hardening resin composition of the present invention may be equipped with an organic solvent for the preparation of the resin composition or for adjusting the viscosity for coating on a substrate or a carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. Such organic solvents may be used singly or in a mixture of two or more.

(Other components) 硬化 The curable resin composition of the present invention may further contain components such as a mercapto compound, an adhesion promoter, a thermosetting catalyst, an antioxidant, an ultraviolet absorber, and the like, as necessary. These systems may use well known ones. In addition, well-known thickeners such as micronized silicon dioxide, hydrotalcite, organic bentonite, and microcrystalline kaolinite can be blended, and defoamers and / or leveling agents such as silicone, fluorine, and polymer systems can be blended. Well-known additives such as silane coupling agents, rust inhibitors and the like.

The curable resin composition of the present invention having the structure described above can be suitably used to form a resin layer (B) in a laminated structure described later, which has a resin layer (A) And a resin layer (B) laminated on the flexible printed wiring board through the resin layer (A).

(Laminated Structure) The laminated structure of the present invention includes a resin layer (A) and a resin layer (B) laminated on a substrate such as a flexible printed wiring board through the resin layer (A). In view of this, in the laminated structure of the present invention, the resin layer (A) and the resin layer (B) substantially function as an adhesive layer and a protective layer, respectively. The resin layer (B) is formed of the above-mentioned curable resin composition, and the resin layer (A) is formed of an alkali-developing resin composition containing an alkali-soluble resin and a heat-reactive compound, and this point is the present invention The characteristics of the laminated structure.

In the present invention, in the laminated structure obtained by laminating two resin layers, the resin layer (B) on the upper side of the laminated structure is made of the curable resin composition of the present invention. Therefore, excellent heat resistance can be achieved without impairing the developability. In addition, the use of polyimide resins as alkali-soluble resins other than polyimide resins can provide excellent heat resistance or low resilience without compromising developability, and can be used after heating. The warpage becomes smaller. Furthermore, by including the core-shell rubber particles in the curable resin composition of the present invention, it is possible to obtain a laminated structure having excellent developability or heat resistance, and particularly softness after solder reflow. body. When the core-shell rubber particles are contained in the lower-layer resin layer (A) in the laminated structure, the adhesion may be reduced. However, the core-shell rubber particles are made of the above-mentioned curable resin composition containing the core-shell rubber particles. In the resin layer (B) on the upper layer side, the effect of improving the flexibility by the core-shell rubber particles can be obtained without lowering the adhesion. Therefore, in the present invention, it is preferable that the core-shell rubber particles are not contained in the resin layer (A).

[Resin layer (A)] (Alkali-developing resin composition) As the alkali-developing resin composition constituting the resin layer (A), as long as it is an alkali-soluble resin containing an alkali-soluble resin and a thermally reactive compound, development can be performed using an alkali solution. Resin composition is sufficient. As a preferable alkali-soluble resin, the resin composition containing the compound which has a phenolic hydroxyl group, the compound which has a carboxyl group, and the compound which has a phenolic hydroxyl group and a carboxyl group is mentioned, A well-known person can be used.

Examples of the resin composition that has been conventionally used as a solder resist composition include a resin containing a carboxyl group or a photosensitive resin containing a carboxyl group, a compound having an ethylenically unsaturated bond, and a thermally reactive compound.

Here, as the carboxyl group-containing resin or the carboxyl group-containing photosensitive resin, and the compound having an ethylenically unsaturated bond, a commonly-known compound can be used, and as the thermally reactive compound, a cyclic (thio) ether can be used. A well-known conventionally used functional group such as a functional group that can undergo a curing reaction by heat.

Although such a resin layer (A) may or may not contain a photopolymerization initiator, examples of the photopolymerization initiator used when the photopolymerization initiator is included include those described above with respect to the curable resin composition. The photopolymerization initiator used is the same.

The resin layer (A) may contain other components, such as a polymer resin, an inorganic filler, a colorant, and an organic solvent, which are the same as those of the curable resin composition.

[Resin layer (B)] The resin layer (B) is formed by the aforementioned hardening resin composition containing an alkali-soluble polyfluorene imine resin, other alkali-soluble resins, and a hardening compound. There are no particular restrictions on other points.

Here, as the above-mentioned alkali-soluble polyfluorene imine resin, other alkali-soluble resins, curable compounds, and the like, the same resins and compounds as those constituting the curable resin composition of the present invention can be used. The curable resin composition constituting the resin layer (B) preferably contains an alkali-soluble resin other than a polyimide resin, more preferably a polyimide resin, and more preferably a polyimide resin. The polyamidamine / imide resin having the structure represented by the general formula (1) and the structure represented by the general formula (2). By having such a structure, it is possible to obtain a resin composition which does not impair the developability and has more excellent properties such as bending resistance and heat resistance.

Since the laminated structure of the present invention is excellent in flexibility, at least one of a bent portion and a non-bent portion of an electronic component such as a flexible printed wiring board can be used as a flexible printed wiring, for example. At least any one of a cover film, a solder resist, and an interlayer insulating material of a board.

The laminated structure of the present invention configured as described above is preferably used as a dry film which is supported or protected by a film on at least one side.

(Dry film) The dry film system can be produced in the following manner, for example. That is, first, the hardening resin composition constituting the resin layer (B) and the alkali-developing resin composition constituting the resin layer (A) are first diluted with an organic solvent and adjusted to an appropriate viscosity. According to a conventional method, a doctor blade type is used. A known method such as coating is sequentially applied to a carrier film (support film). After that, it is usually dried at a temperature of 50 to 130 ° C. for 1 to 30 minutes, so that a dry film in which a coating film of the resin layer (B) and the resin layer (A) is formed on the carrier film can be produced. A peelable cover film (protective film) may be further laminated on the dry film for the purpose of preventing dust or the like from being deposited on the surface of the coating film. As the carrier film and the cover film, a conventionally known plastic film can be suitably used. When the cover film is peeled off, the adhesive force between the resin layer and the carrier film is preferably smaller. There is no particular limitation on the thickness of the carrier film and the cover film, but it is usually selected within a range of 10 to 150 μm.

(Hardened product) 硬化 The cured product of the present invention is obtained by curing the aforementioned curable resin composition of the present invention or the aforementioned laminated structure of the present invention.

(Electronic component) The curable resin composition and the laminated structure of the present invention as described above can be effectively used for electronic components such as flexible printed wiring boards. Specifically, the flexible printed wiring substrate has a layer on which a curable resin composition or a laminated structure of the present invention is formed, and is patterned by light irradiation and patterned by a developer. A flexible printed wiring board or the like formed of a cured product of an insulating film. Hereinafter, as an example of the electronic component, a method for manufacturing a flexible printed wiring board will be specifically described.

(Manufacturing method of flexible printed wiring board) (1) The manufacturing of the flexible printed wiring board using the laminated structure of this invention can be performed according to the procedure shown in the step diagram of FIG. 1, for example. That is, the manufacturing method includes the steps of forming a layer of the layered structure of the present invention on a flexible printed wiring substrate on which a conductor circuit has been formed (layering step); and forming the layered structure. A step of irradiating an active energy ray with a pattern in a pattern (exposure step); and a step of subjecting the layer of the laminated structure to alkali development to form a patterned layer of the laminated structure (development step) ). In addition, if necessary, further light curing or thermal curing (post-curing step) is performed after the alkali development to completely cure the layers of the laminated structure, thereby obtaining a flexible printed wiring board with high reliability.

Moreover, the manufacture of the flexible printed wiring board using the laminated structure of this invention can also be performed according to the procedure shown in the step diagram of FIG. 2, for example. That is, the manufacturing method includes the steps of forming a layer of the layered structure of the present invention on a flexible printed wiring substrate on which a conductor circuit has been formed (layering step); and forming the layered structure. The step of irradiating the active energy rays with a pattern (exposure step); the step of heating the layer of the laminated structure (heating (PEB) step); and subjecting the layer of the laminated structure to alkali development, Thereby, a step of forming a patterned layered structure (development step). In addition, if necessary, further light curing or thermal curing (post-curing step) is performed after the alkali development to completely cure the layers of the laminated structure, thereby obtaining a flexible printed wiring board with high reliability.

Hereinafter, each step in FIG. 1 or FIG. 2 will be described in more detail. [Lamination Step] 中 In this step, a laminated structure is formed on the flexible printed wiring substrate 1 on which the conductor circuit 2 has been formed. The laminated structure system is composed of the following layers: containing alkali dissolution A resin layer 3 (resin layer (A)) made of an alkali-developing resin composition such as a flexible resin and a resin layer 4 (resin layer (B) made of the curable resin composition of the present invention above the resin layer 3 )). Here, each resin layer constituting the laminated structure can be formed by, for example, coating and drying the resin composition constituting the resin layers 3 and 4 on the wiring substrate 1 in order to form the resin layer 3. , Or a method of forming the resin composition constituting the resin layers 3 and 4 into a dry film having a two-layer structure and laminating it on the wiring substrate 1.

As a method for applying the resin composition to the wiring substrate, a known method such as doctor blade coating, lip and mouth coating, doctor blade coating, and film coating machine can be used. In addition, the drying method may be a method using a hot air circulation type drying furnace, an IR furnace, a heating plate, a convection constant temperature oven, and the like, which are provided with a heating source using a steam heating method, to contact the hot air in the dryer by convection, and a nozzle A well-known method, such as the method of blowing to a support body.

[Exposure Step] (1) In this step, the photopolymerization initiator contained in the resin layer 4 is activated to a negative pattern by irradiation with active energy rays, thereby curing the exposed portion. In the case of using the composition of the PEB step described later, a photopolymerization initiator or a photobase generator having a function as a photobase generator is activated to form a negative pattern to generate a base. As an exposure machine used in this step, a direct drawing device, an exposure machine equipped with a metal halide lamp, or the like can be used. The pattern-shaped exposure mask is a negative mask.

As the active energy ray for exposure, it is preferable to use laser light or scattered light having a maximum wavelength in a range of 350 to 450 nm. By setting the maximum wavelength within this range, the photopolymerization initiator can be effectively activated. The exposure amount varies depending on the film thickness and the like, but it can be set to, for example, 50 to 1500 mJ / cm ² .

[PEB step] In this step, the exposed portion is hardened by heating the resin layer after exposure. In this step, an exposure step using a photopolymerization initiator having a function as a photobase generator or a resin layer (B) formed by using a combination of a photopolymerization initiator and a photobase generator in combination is used. The generated alkali can harden the resin layer (B) to a deep part. The heating temperature is, for example, 70 to 150 ° C. The heating time is, for example, 1 to 120 minutes. Since the hardening of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, strain or hardening shrinkage can be suppressed more than when the hardening is performed by a photoradical reaction.

[Developing step] (1) In this step, the unexposed portions are removed by alkali development to form a negative patterned insulating film (for example, a cover film) and a solder resist. As a development method, a well-known method, such as immersion, can be used. As the developing solution, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkali aqueous solutions such as tetramethylammonium hydroxide aqueous solution (TMAH), or the like can be used. Mixed liquid.

[Post-curing step] After the developing step, the insulating film may be further irradiated with light, or it may be heated at 150 ° C. or higher, for example. [Example]

Hereinafter, the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited by these examples and comparative examples.

(Synthesis Example 1) 对于 A dimer diamine (a) -derived dimer acid-derived fat of 36 carbon atoms was fed to a four-necked 300 mL flask equipped with a nitrogen introduction tube, a thermometer, and a stirrer at room temperature. Group diamine (Croda Japan Corporation, product name PRIAMINE 1075) 28.61 g (0.052 mol), 4.26 g (0.028 mol) of 3,5-diaminobenzoic acid as a diamine (b) containing a carboxyl group, γ-butane 85.8 g of the ester were dissolved.

Next, 30.12 g (0.152 mol) of cyclohexane-1,2,4-tricarboxylic anhydride (c) and 3.07 g (0.016 mol) of trimellitic anhydride (d) were fed and kept at room temperature for 30 minutes. 30 g of toluene was further fed, and the temperature was raised to 160 ° C. After removing water generated simultaneously with toluene, the solution was kept at room temperature for 3 hours and then cooled to room temperature to obtain a solution containing sulfonium imide.

14.30 g (0.068 mol) of trimethylhexamethylene diisocyanate as the diisocyanate compound (e) was fed to the obtained sulfonium imide-containing solution, and the temperature was maintained at 160 ° C for 32 hours. And diluted with 21.4 g of cyclohexanone to obtain a solution (A-1) containing a polyamidofluorine imine resin. The mass average molecular weight Mw of the obtained polyamidoamine imine resin was 5250, the solid content was 41.5% by mass, the acid value was 63mgKOH / g, and the content of the dimer diamine (a) was 40.0% by mass.

(Synthesis example 2) A dimer diamine (a) -derived dimer acid-derived fat of 36 carbon atoms was fed to a four-necked 300 mL flask equipped with a nitrogen introduction tube, a thermometer, and a stirrer at room temperature. Group diamine (Croda Japan Corporation, product name PRIAMINE 1075) 29.49 g (0.054 mol), 4.02 g (0.026 mol) of 3,5-diaminobenzoic acid as a diamine (b) containing a carboxyl group, γ-butane 73.5 g of the ester were dissolved.

Next, 31.71 g (0.160 mol) of cyclohexane-1,2,4-tricarboxylic anhydride (c) and 1.54 g (0.008 mol) of trimellitic anhydride (d) were fed and kept at room temperature for 30 minutes. 30 g of toluene was further fed, and the temperature was raised to 160 ° C. After removing water generated simultaneously with toluene, the solution was kept at room temperature for 3 hours and then cooled to room temperature to obtain a solution containing sulfonium imide.

To the obtained sulfonium imide-containing solution, 6.90 g (0.033 mol) of trimethylhexamethylene diisocyanate and 8.61 g (0.033 mol of dicyclohexylmethane diisocyanate) as the diisocyanate compound (e) were fed. ), And kept at 160 ° C. for 32 hours, and diluted with 36.8 g of cyclohexanone to obtain a solution (A-2) containing a polyamidofluorene imine resin. The obtained polyamidofluorene imine resin had a mass average molecular weight Mw of 5840, a solid content of 40.4% by mass, an acid value of 62mgKOH / g, and a dimer diamine (a) content of 40.1% by mass.

(Synthesis example 3) At room temperature, a four-necked 300 mL flask equipped with a nitrogen introduction tube, a thermometer, and a stirrer was fed with 2,2'-bis [4- (4-aminophenoxy) phenyl] propane 6.98 g, 3.80 g of 3,5-diaminobenzoic acid, 8.21 g of polyetherdiamine (manufactured by Huntsman, product name ELASTAMINE RT1000, molecular weight 1025.64), and 86.49 g of γ-butyrolactone were dissolved.

Next, 17.84 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and 2.88 g of trimellitic anhydride were fed and kept at room temperature for 30 minutes. 30 g of toluene was further fed, and the temperature was raised to 160 ° C. After removing water generated simultaneously with toluene, the solution was kept at room temperature for 3 hours and then cooled to room temperature to obtain a sulfonium imide solution.

To the obtained amidine imide solution, 9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were fed, and the temperature was maintained at 160 ° C. for 32 hours. In this manner, a polyamidoamine imine resin solution (A-3) containing a carboxyl group was obtained. The solid content was 40.1% by mass, and the acid value was 83 mgKOH / g.

(Synthesis Example 4) 22.4 g of 3,3'-diamino-4,4'-dihydroxydiphenylphosphonium was added to a liquid-separated 3-necked flask equipped with a stirrer, a nitrogen introduction tube, a fractionation ring, and a cooling ring. 8.2g of 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 30g of NMP, 30g of γ-butyrolactone, 27.9g of 4,4'-oxydiphthalic anhydride And 3.8 g of trimellitic anhydride, and stirred at 100 rpm for 4 hours under a nitrogen environment at room temperature. Next, 20 g of toluene was added, and toluene and water were distilled off at a silicon bath temperature of 180 ° C. and 150 rpm, and stirred for 4 hours to obtain a polyfluorene imine resin solution (PI-1) having a phenolic hydroxyl group and a carboxyl group. The acid value of the obtained resin (solid content) was 18 mgKOH, Mw was 10,000, and hydroxyl equivalent was 390.

(Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2) According to the component composition described in Table 1, Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1- The material described in 2 was pre-mixed with a blender and kneaded with a three-roll mill to prepare each resin composition for forming a resin layer. Unless otherwise specified, the values in the table are mass parts of solid content.

<Formation of Resin Layer> (1) A flexible printed wiring substrate having a circuit having a copper thickness of 18 μm was prepared, and pre-treatment was performed using MEC CZ-8100. After that, on the flexible printed wiring substrate subjected to the pretreatment, the coatings of Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 were applied so that the film thickness after drying became 30 μm, respectively. Each obtained resin composition. After that, it was dried at 90 ° C. for 30 minutes in a hot-air circulation drying furnace to form an unhardened resin layer.

<Developability (Alkali solubility)> The resin layer is formed as described above. For the uncured resin layer on each flexible printed wiring substrate, an exposure device (HMW-680- GW20), and pattern exposure was performed through a negative mask so that an opening having a diameter of 200 μm was formed at 300 mJ / cm ² . The substrate having the exposed resin layer was heat-treated at 90 ° C for 30 minutes. After that, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 1 minute, and the state of pattern formation was observed and developability (alkali solubility) was evaluated. The evaluation criteria are as follows. ：: The exposed portion exhibits developing resistance, and the unexposed portion exhibits developability, so the pattern formation is good. ×: Although the unexposed portion exhibits developability, the resolution pattern is formed to be poor (resolution is insufficient).

<Heat resistance (solder heat resistance)> (Production of evaluation substrate) A resin layer is formed as described above, and for the uncured resin layer on each flexible printed wiring substrate, exposure using a metal halide lamp is first used. The device (HMW-680-GW20) performs pattern exposure through a negative mask so that an opening with a diameter of 200 μm is formed at 300 mJ / cm ² . Then, after performing a PEB step at 90 ° C for 30 minutes, development (30 ° C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution) was performed for 60 seconds, and heat curing was performed at 150 ° C × 60 minutes to form a film. Flexible printed wiring board (evaluation board) with a cured resin layer. (Evaluation method) The rosin-based flux was applied to the evaluation substrate prepared as described above, and immersed in a solder bath set at 260 ° C for 20 seconds (10 seconds x 2 times) to observe the cured coating film ( Resin layer) to expand and peel and evaluate heat resistance (solder heat resistance). The evaluation criteria are as follows. ○: No swelling or peeling even after immersing for 10 seconds x 2 times. ×: When immersed for 10 seconds × 1 time, swelling and peeling occurred.

<Chemical resistance (gold-plating resistance)> The evaluation board was evaluated by the following method using the same evaluation substrate as the aforementioned evaluation of heat resistance. For the evaluation substrate, a commercially available electroless nickel plating bath and an electroless gold plating bath were used, and plating of 5 μm of nickel and 0.05 μm of gold was performed at 80 to 90 ° C., and the substrate and the resin layer were observed to evaluate chemical resistance. Resistance (gold resistance). The evaluation criteria are as follows. ○: There is no infiltration between the substrate and the coating film (resin layer). △: Infiltration was confirmed between the substrate and the coating film (resin layer). ×: Part of the coating film (resin layer) was peeled.

<Resilience (spring resilience / spring back)> (Production of test piece) Examples 1-1 to 1-9 and Comparative Examples were coated on a polyimide film so that the film thickness after drying became 30 μm. Each of the resin compositions obtained in 1-1 and 1-2 was dried in a hot-air circulation-type drying oven at 90 ° C. for 30 minutes to form an unhardened resin layer. Thereafter, an exposure device (HMW-680-GW20) equipped with a metal halide lamp was used to perform exposure at 300 mJ / cm ² without passing through a mask. Then, after performing the PEB step at 90 ° C for 30 minutes, development (30 ° C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution) was performed for 60 seconds, and heat curing was performed at 150 ° C × 60 minutes to thereby A test piece of a polyimide film with a cured resin layer formed. (Evaluation method) The polyimide film test piece prepared as described above was cut into 2 cm × 7 cm, and the two ends on the long side were brought together to form a band ring. Partially fixed on the electronic balance. When the ring was loosened, the glass was pressed against the ring and the measurement was performed so that the vertical distance between the rings was 3 mm. The load was used as the resilience (g) to evaluate the resilience (resilience). The evaluation criteria are as follows. ○: Less than 30 g. △: 30 g or more and less than 45 g. ×: 45 g or more.

<Warpage amount after hardening> 评估 Using the same test piece as the above-mentioned evaluation of resilience, it was evaluated by the following method. After cutting the test piece into 5cm × 5cm, place the substrate on a horizontal test bench with the warped surface facing upward, and use a ruler to measure 4 parts from the test bench to the respective vertices in 1mm units. The distance at which the maximum value of the four parts was set as the amount of warpage, and the amount of warpage after hardening was evaluated. The evaluation criteria are as follows. ○: The amount of warpage is less than 3 mm. △: The warpage amount is 3 mm or more and less than 6 mm. ×: 6mm or more

The results of these evaluations are shown in Table 2.

(Examples 1-10 to 1-12) According to the component composition described in Table 3, the materials described in Examples 1-10 to 1-12 were respectively prepared, premixed with a mixer, and then kneaded with a three-roll mill. Thus, each resin composition for forming the resin layer (A) and each resin composition for forming the resin layer (B) are prepared. Unless otherwise specified, the values in the table are mass parts of solid content.

<Formation of Resin Layer (A)> A flexible printed wiring substrate on which a circuit having a copper thickness of 18 μm is formed is prepared and pretreated using MEC CZ-8100. Thereafter, on the flexible printed wiring substrate subjected to the pretreatment, the resin layers (A) obtained in Examples 1-10 to 1-12 were applied so that the film thickness after drying became 20 μm, respectively. Of each resin composition. After that, it was dried at 90 ° C. for 30 minutes in a hot-air circulation drying furnace to form a resin layer.

<Formation of Resin Layer (B)> The resins obtained in Examples 1-10 to 1-12 were applied on top of the resin layer (A) formed above so that the film thickness after drying became 10 μm. Each resin composition of the layer (B). Thereafter, the resin layer (B) was formed by drying in a hot-air circulation-type drying furnace at 90 ° C for 30 minutes.

In this manner, an unhardened laminated structure formed of the resin layer (A) and the resin layer (B) described in Examples 1-10 to 1-12 was formed on a flexible printed wiring substrate. .

For the uncured laminated structure formed as described above, the uncured resins in Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 were implemented by the same method. The evaluations performed by the layers.结果 The results of these evaluations are shown in Table 4.

From the evaluation results shown in Tables 2 and 4, it was confirmed and understood that the resin composition system of each example can obtain excellent developability or heat resistance, low resilience, and low warpage after heating.

(Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2-2) According to the component composition described in Table 5, Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2- were prepared, respectively. The material described in 2 is premixed with a blender and kneaded with a three-roll mill to prepare a resin composition for forming each resin layer. Unless otherwise specified, the values in the table are mass parts of solid content.

<Formation of Resin Layer (A)> A flexible printed wiring substrate on which a circuit having a copper thickness of 18 μm is formed is prepared and pretreated using MEC CZ-8100. After that, the flexible printed wiring substrates subjected to the pretreatment were coated in a manner such that the film thickness after drying became 25 μm to constitute Examples 2-1 to 2-4 and Comparative Examples 2-1 and 2-2. The resin composition of each obtained resin layer (A). Thereafter, the resin layer (A) was formed by drying in a hot-air circulation-type drying oven at 90 ° C for 30 minutes.

<Formation of Resin Layer (B)> 涂布 On the resin layer (A) formed as described above, coating was performed so that the film thickness after drying became 10 μm to constitute Examples 2-1 to 2-4 and Comparative Example 2-1. , 2-2 Resin composition of each resin layer (B) obtained. Thereafter, the resin layer (B) was formed by drying in a hot-air circulation-type drying furnace at 90 ° C for 30 minutes.

In this manner, the resin layer (A) and the resin layer (B) described in Examples 2-1 to 2-4 and Comparative Examples 2-1 and 2-2 were formed on a flexible printed wiring substrate. Unhardened laminated structure.

<Developability (alkali solubility)> A laminated structure is formed as described above, and an unhardened laminated structure on each flexible printed wiring substrate is firstly exposed using a metal halide lamp ( HMW-680-GW20), pattern exposure was performed through a negative mask so that an opening with a diameter of 200 μm was formed at 500 mJ / cm ² . The substrate having the uncured laminated structure after exposure was heat-treated at 90 ° C for 30 minutes. After that, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C. and developed for 1 minute to evaluate whether a 200 μm opening pattern can be formed. The evaluation criteria are as follows. ：: The exposed portion exhibits developing resistance, and the unexposed portion exhibits developability, so the pattern formation is good. Δ: Although the unexposed portion exhibits developability, the developed portion has insufficient development resistance, so that a pattern cannot be formed. ×: Since the unexposed part cannot be dissolved in the developing solution, the pattern cannot be formed.

<Heat resistance> The laminated structure is formed as described above. For an unhardened laminated structure on each flexible printed wiring substrate, an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp is first used. ), Pattern exposure was performed through a negative mask in such a manner that an opening having a diameter of 200 μm was formed at 500 mJ / cm ² . Then, after performing a PEB step at 90 ° C for 30 minutes, development (30 ° C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution) was performed for 60 seconds, and heat curing was performed at 150 ° C × 60 minutes to produce A flexible printed wiring board (evaluation substrate) on which a cured laminated structure is formed. A rosin-based flux was applied to the evaluation substrate, and immersed in a solder bath set at 260 ° C for 20 seconds (10 seconds x 2 times), and the swelling and peeling of the cured coating film were evaluated. The evaluation criteria are as follows. ○: No swelling or peeling even after immersing for 10 seconds x 2 times. ×: When immersed for 10 seconds × 1 time, swelling and peeling occurred, so the adhesion was insufficient.

<Flexibility (bending test after solder reflow at 260 ° C)> The above evaluation substrate was passed through a reflow furnace set to a maximum of 260 ° C three times to obtain a test piece, and the test piece was subjected to bending by the following test method. Evaluation of discounts. The test piece was sandwiched between two flat plates, and the hardened coating film was bent outward to show a state of 180 °, and a load G (1 kg standard weight) was applied for 10 seconds to perform sheet metal bending. Thereafter, it was confirmed whether cracks were generated in the hardened coating film portion of the bent portion using an optical microscope, and the operation so far was set to 1 cycle, and the number of times until the cracks were generated was recorded. The evaluation criteria are as follows. ◎: Bend 20 times or more. ○: Bend 10 times or more and less than 20 times. △: Bend 5 times or more and less than 10 times. ×: Less than 5 times of bending.

The results of these evaluations are shown in Table 6.

From the evaluation results shown in the above table, it can be confirmed and known that, in addition to the excellent developability and heat resistance, the laminated structure of each example can obtain good flexibility even after solder reflow.

Next, for the resin composition constituting the resin layer (B) of Example 2-5, a flexible printed wiring substrate on which a circuit having a copper thickness of 18 μm was formed, the above-mentioned resin layer (B) was used and formed as follows: The coating film was formed in the same manner. About the obtained coating film, the said resolution, heat resistance, and flexibility were evaluated. The evaluation results are shown in Table 7.

1‧‧‧ Flexible printed wiring substrate

2‧‧‧ conductor circuit

3‧‧‧ resin layer

4‧‧‧ resin layer

5‧‧‧Mask

[Fig. 1] Fig. 1 is a process chart simulating and showing a method for manufacturing a flexible printed wiring board as an example of an electronic component of the present invention. [FIG. 2] A process chart simulating another example of a method for manufacturing a flexible printed wiring board shown as an example of an electronic component of the present invention.

Claims (10)

A curable resin composition comprising an alkali-soluble polyimide resin, an alkali-soluble resin other than the polyimide resin, and a curable compound. The curable resin composition according to claim 1, wherein the alkali-soluble resin other than the polyimide resin is a polyimide resin. The curable resin composition according to claim 2, wherein the polyamidoamine imine resin is a polyamidoamine having a structure represented by the following general formula (1) and a structure represented by the following general formula (2)醯 imine resin, (X ₁ is a residue of an aliphatic diamine (a) derived from a dimer acid having 24 to 48 carbons, X ₂ is a residue of an aromatic diamine (b) having a carboxyl group, and Y is independently a ring Hexane ring or aromatic ring). The curable resin composition according to any one of claims 1 to 3, further comprising core-shell rubber particles. The curable resin composition according to any one of claims 1 to 4, wherein the polyfluorene imine resin has a carboxyl group. The curable resin composition according to claim 5, wherein the polyimide resin has a carboxyl group and a phenolic hydroxyl group. The curable resin composition according to any one of claims 1 to 6, wherein the curable compound is an epoxy resin. A laminated structure comprising a resin layer (A) and a resin layer (B) laminated on a substrate through the resin layer (A), wherein the resin layer (B) is composed of The hardening resin composition according to any one of claims 1 to 7, and the resin layer (A) is made of an alkali-developing resin composition containing an alkali-soluble resin and a heat-reactive compound. A hardened product characterized by being made of a hardenable resin composition according to any one of claims 1 to 7 or a laminated structure according to claim 8. An electronic part characterized by having an insulating film made of a hardened material as claimed in claim 9.