KR20180111607A - Curable resin composition, laminate structure, cured product thereof, and electronic component - Google Patents

Abstract

Provided is 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 with less bending after heated. In addition, provided is 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). To this end, the curable resin composition contains an alkali soluble polyimide resin, an alkali soluble resin other than the polyimide resin, and a curable compound.

Description

TECHNICAL FIELD [0001] The present invention relates to a curable resin composition, a laminated structure, a cured product thereof, and an electronic component thereof (CURABLE RESIN COMPOSITION, LAMINATE STRUCTURE, CURED PRODUCT THEREOF, AND ELECTRONIC COMPONENT)

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

2. Description of the Related Art In recent years, miniaturization of electronic devices due to the spread of smart phones and tablet terminals has made it necessary to make electronic parts such as circuit boards small in size. Therefore, the flexible printed wiring board that can be folded and housed is being used more widely, and a flexible printed wiring board is required to have higher reliability than ever.

On the other hand, a coverlay based on polyimide excellent in mechanical properties such as heat resistance and bending property is used as the insulating film for securing the insulation reliability of the flexible printed wiring board at the bent portion (bent portion) (for example, (See Patent Documents 1 and 2), and a mixed process using a photosensitive resin composition which is excellent in electric insulation property, solder heat resistance and the like and can be micromachined is widely adopted in the mounting portion (non-curved portion).

That is, the coverlay based on polyimide is not suitable for fine wiring because it requires machining by die punching. For this reason, it is necessary to partially use an alkali development type photosensitive resin composition (solder resist) which can be processed by photolithography, in the chip mounting portion where fine wiring is required.

Japanese Patent Application Laid-Open No. 62-263692 Japanese Patent Application Laid-Open No. 63-110224

As described above, in the manufacturing process of the conventional flexible printed wiring board, there is a problem in that cost and operability are deteriorated because it is necessary to adopt a mixed process of the step of aligning the coverlay and the step of forming the solder resist.

On the contrary, in the past, it has been studied to apply an insulating film as a solder resist or an insulating film as a coverlay as a solder resist and a coverlay of a flexible printed wiring board. However, Has not yet been put to practical use.

The solder resist and the coverlay are required to have various properties such as excellent developability (alkali solubility), heat resistance (soldering heat resistance), low rebound characteristics (spring returnability) and small warpage after heating do. However, when an alkali soluble resin having a large molecular weight is used to improve low rebound properties and warping properties after heating while ensuring heat resistance, there arises a problem that development can not be performed. Further, the imide resin has heat resistance, but has a difficulty in that warpage after curing is large, and the urethane resin has a problem that it is low in rebound and low in bending but poor in heat resistance. Therefore, all of the conventionally proposed compositions using various resins can not satisfy all requirements that the developability is not impaired, the heat resistance and the low repulsion are excellent, and the warp after heating is small.

SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide a curable resin composition that satisfies the required performance of both solder resist and coverlay and is excellent in heat resistance and low rebound properties without deteriorating developability and having small warpage after heating .

Another object of the present invention is to provide a curable resin composition, a laminated structure, a cured product thereof, and a cured product thereof, which are suitable for a process for collectively forming an insulating film such as a flexible printed wiring board, particularly a bending part (bending part) and a mounting part For example, a flexible printed wiring board having a protective layer such as a coverlay or a solder resist.

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have completed the present invention with the following content.

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, it is preferable that the alkali soluble resin other than the polyimide resin is a polyamideimide resin, and the polyamideimide resin has a structure represented by the following general formula (1) 2). ≪ / RTI >

(X ₁ is a residue of an aliphatic diamine (a) 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, and Y is each independently a cyclohexane ring or an aromatic ring)

Further, the curable resin composition of the present invention preferably further contains core-shell rubber particles. Further, in the curable resin composition of the present invention, the polyimide resin preferably has a carboxyl group, and more preferably has a carboxyl group and a phenolic hydroxyl group.

In the curable resin composition of the present invention, it is preferable that the curable compound is an epoxy resin.

The laminated structure of the present invention is a laminated structure body having a resin layer (A) and a resin layer (B) laminated on the substrate via the resin layer (A)

Characterized in that the resin layer (B) comprises the curable resin composition, and the resin layer (A) comprises an alkali-soluble resin composition comprising an alkali-soluble resin and a heat-reactive compound.

Further, the cured product of the present invention is characterized by including the curable resin composition or the laminated structure.

Further, the electronic component of the present invention is characterized by having an insulating film containing the cured product.

Examples of the electronic component of the present invention include those having an insulating film formed by forming a layer of the above-described laminated structure on a flexible printed wiring board, patterning it by light irradiation, and collectively forming patterns with a developing solution. It is also possible to form the resin layer (A) and the resin layer (B) sequentially on the flexible printed wiring board without using the laminated structure, patterning the resin layer (B) by light irradiation, It may have an insulating film. In the present invention, the term " pattern " means a patterned cured product, that is, an insulating film.

According to the present invention, it is possible to provide a curable resin composition which satisfies the required performance of both the solder resist and the coverlay, is excellent in heat resistance and low repulsion, and has small warpage after heating without deteriorating developability. In addition, a curable resin composition, a laminated structure, a cured product thereof, and a cured product thereof suitable for a process for collectively forming an insulating film of an electronic component such as a flexible printed wiring board, particularly a bending part (bending part) and a mounting part , A flexible printed wiring board having a protective film such as a coverlay or a solder resist, or the like can be realized.

Fig. 1 is a process diagram schematically showing a manufacturing method of a flexible printed wiring board showing an example of an electronic component of the present invention.
Fig. 2 is a process diagram schematically showing another example of a manufacturing method of a flexible printed wiring board showing an example of an electronic component of the present 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 resin, and a curable compound.

By containing the alkali soluble polyimide resin, the other alkali soluble resin and the curable compound, it is possible to realize a curable resin composition that satisfies the required performance of both the solder resist and the coverlay, and is excellent in developability and heat resistance.

(Alkali soluble polyimide resin)

As the alkali-soluble polyimide resin, any one that contains at least one functional group in the phenolic hydroxyl group and the carboxyl group and can be developed into an alkali solution is used, and a known one is used.

According to this polyimide resin, properties such as flex resistance and heat resistance are more excellent.

Such an alkali-soluble polyimide resin is, for example, a resin 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. The imidization may be performed by thermal imidization, chemical imidization, or both.

Examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride and tricarboxylic acid anhydride. However, the acid anhydride is not limited to these acid anhydrides, and if it is a compound having an acid anhydride group and a carboxyl group which react with an amino group or an isocyanate group, Derivatives thereof. These carboxylic acid anhydride components may be used alone or in combination.

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

Examples of the isocyanate component include diisocyanates such as aromatic diisocyanates, isomers and isomers thereof, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general diisocyanates. However, the diisocyanates are not limited to these isocyanates no. These isocyanate components may be used alone or in combination.

In the synthesis of such an alkali-soluble polyimide resin, a known organic solvent may be used. Such an organic solvent is not particularly limited as long as it is a solvent which does not react with carboxylic anhydrides, amines and isocyanates and also dissolves these raw materials. Particularly, from the viewpoint of high solubility of the starting materials, non-protonic substances such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl- Solvents are preferred.

From the viewpoint of improving the balance between the alkali solubility (developability) of the polyimide resin and other characteristics such as the mechanical properties of the cured product of the resin composition comprising the polyimide resin, the alkali soluble polyimide resin The acid value (solid acid value) is preferably 20 to 200 mgKOH / g, more preferably 60 to 150 mgKOH / g. Concretely, when the acid value is 20 mgKOH / g or more, the alkali solubility, that is, the developability is improved, the cross-linking density with the thermosetting component after irradiation is increased, and sufficient development contrast can be obtained. Further, by setting the acid value to 200 mgKOH / g or less, so-called thermal fogging in the post exposure bake (PEB) process after light irradiation described later can be suppressed, and the process margin is increased.

The molecular weight of such an alkali soluble polyimide resin is preferably 100,000 or less, more preferably 1,000 to 100,000, and even more preferably 2,000 to 50,000, in view of development and cured coating film characteristics. When the molecular weight is 100,000 or less, the alkali solubility of the unexposed portion increases, and the developability is improved. On the other hand, if the molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained in the exposed portion after the exposure / PEB process.

(Alkali soluble resin other than polyimide resin)

Such an alkali-soluble resin may be any as long as it can contain at least one functional group of a phenolic hydroxyl group and a carboxyl group and can be developed into an alkali solution, and a known one is used. For example, a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin conventionally used in a solder resist can be used.

In particular, an alkali soluble polyamideimide resin can be suitably used from the viewpoint of obtaining a resin composition having excellent properties such as flex resistance and heat resistance without deteriorating developability.

By using such an alkali soluble polyamideimide resin in combination with the alkali soluble polyimide resin described above, it is possible to provide a curable resin composition which is excellent in heat resistance and low rebound, low in dielectric strength and low in warpage after heating, without deteriorating developability .

The mixing ratio of the alkali-soluble polyamide-imide resin to the alkali-soluble polyimide resin is preferably from 98: 2 to 50:50 in mass ratio, more preferably from 90:10 to 50:50 .

(Alkali soluble polyamideimide resin)

In the curable resin composition of the present invention, the alkali soluble polyamideimide resin may be any of those which contain at least one functional group in the phenolic hydroxyl group and the carboxyl group and can be developed into an alkali solution, and those known in the art are used.

Such an alkali soluble polyamideimide resin includes, for example, a resin obtained by reacting a carboxylic acid anhydride component and an amine component to obtain an imide compound, and then reacting the obtained imide compound with an isocyanate component. Here, the alkali-soluble group is introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. The imidization may be performed by thermal imidization, chemical imidization, or both.

Examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride and tricarboxylic acid anhydride. However, the acid anhydride is not limited to these acid anhydrides, and if it is a compound having an acid anhydride group and a carboxyl group which react with an amino group or an isocyanate group, Derivatives thereof. These carboxylic acid anhydride components may be used alone or in combination.

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

Examples of the isocyanate component include diisocyanates such as aromatic diisocyanates, isomers and isomers thereof, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general diisocyanates. However, the diisocyanates are not limited to these isocyanates no. These isocyanate components may be used alone or in combination.

The alkali-soluble polyamide-imide resin as described above has a good balance between the alkali solubility (developability) of the polyamide-imide resin and other characteristics such as the mechanical properties of the cured product of the resin composition including the polyamide- , The acid value (solid acid value) thereof is preferably 30 mgKOH / g or more, more preferably 30 mgKOH / g to 150 mgKOH / g, and particularly preferably 50 mgKOH / g to 120 mgKOH / g. Concretely, when the acid value is 30 mgKOH / g or more, the alkali solubility, that is, the developability is improved, the cross-link density with the thermosetting component after light irradiation is high, and sufficient development contrast can be obtained. Further, by setting the acid value to 150 mgKOH / g or less, so-called thermal blur in the post exposure bake (PEB) process after light irradiation described later can be suppressed, and the process margin is increased.

The molecular weight of the alkali-soluble polyamideimide resin is preferably 20,000 or less, more preferably 1,000 to 15,000, and even more preferably 2,000 to 10,000, in view of the developability and the cured coating film characteristics. When the molecular weight is 20,000 or less, the alkali solubility of the unexposed portion increases and the developability is improved. On the other hand, if the molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained in the exposed portion after the exposure / PEB process.

Particularly in the present invention, it is more preferable to use a polyamide-imide resin having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) from the viewpoint of further improving developability.

Here, X < ₁ > is a residue of an aliphatic diamine (a) derived from a dimer acid having a carbon number of 24 to 48 (also referred to as " dimer diamine (a) " X ₂ is a residue of an aromatic diamine (b) having a carboxyl group (also referred to herein as a "carboxyl group-containing diamine (b)"). Each Y is 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), even when a mild alkaline solution such as 1.0% by mass aqueous sodium carbonate solution is used, excellent alkali solubility And a polyamideimide resin. In addition, the cured product of the resin composition comprising such a polyamideimide resin may have excellent dielectric properties.

The 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. Namely, dimer diamine (a), which is an aliphatic diamine derived from dimer acid, is obtained by polymerizing unsaturated fatty acids such as oleic acid and linoleic acid into a dimer acid, reducing it, and then aminating it. As such an aliphatic diamine, for example, a commercially available product such as PRIAMINE 1073, 1074, 1075 (trade name, manufactured by Kuroda Japan Co., Ltd.), which is a diamine having a skeleton of 36 carbon atoms, can be used. The dimer diamine (a) is preferably derived from a dimer acid having a carbon number of 28 to 44, and more preferably a dimer acid derived from a dimer acid having a carbon number of 32 to 40.

Specific examples of the carboxyl group-containing diamine (b) include 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, 5,5'-methylenebis (anthranilic acid), benzidine-3,3'-dicarboxylic acid . The carboxyl group-containing diamine (b) may be composed of one kind of compound or plural kinds of compounds. From the viewpoint of raw material availability, it is preferable that the carboxyl group-containing diamine (b) contains 3,5-diaminobenzoic acid and 5,5'-methylenebis (anthranilic acid).

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) in the polyamideimide resin is not limited. The content (unit: mass%) of the dimer diamine (a) is preferably in the range of from 0.1 to 5 parts by mass, more preferably from 2 to 30 parts by mass, from the viewpoint of improving the balance between the alkali solubility of the polyamideimide resin and the other properties such as the mechanical properties of the cured product of the resin composition comprising the polyamideimide resin Is preferably from 20 to 60 mass%, more preferably from 30 to 50 mass%. In the present specification, the "content of the dimer diamine (a)" means the amount of the dimer diamine (a) placed as one of the raw materials in the production of the polyamideimide resin with respect to the mass of the polyamide- Ratio. Here, the " mass of the polyamideimide resin produced " means that the amount of water (H ₂ O) generated in the imidization and the carbon dioxide gas generated in the amidation (CO ₂ ) ≪ / RTI >

From the viewpoint of enhancing the alkali solubility of the polyamide-imide resin, the moiety represented by Y in the general formula (1) and the general formula (2) preferably has a cyclohexane ring. From the viewpoint of improving the balance between the alkali solubility of the polyamide-imide resin and the other properties such as the mechanical properties of the cured product of the resin composition including the polyamide-imide resin, the amount of the aromatic ring and the cyclohexane ring The relationship is preferably a molar ratio of the content of cyclohexane rings to the content of aromatic rings of 85/15 to 100/0, more preferably 90/10 to 99/1, and more preferably 90/10 to 98/2 desirable.

The polyamideimide resin may further have a partial structure represented by the following general formula (i).

Herein, X ₃ is a residue of a diamine (f) other than the diamine diamine (a) and the carboxyl group-containing diamine (b) (also referred to herein as "other diamine (f)") 1) and the above-mentioned general formula (2) are each independently an aromatic ring or a cyclohexane ring. The other diamine (f) may be composed of one kind of compound or a plurality of kinds of compounds.

Specific examples of other diamines (f) include bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (Aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, bis [4- Bis (4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ketone, (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'-sulfonyl- Diamine, 3,3'-dihydroxybiphenyl-4,4'-diamine, (4,4'-diamino) diphenyl ether, (4,4'-diamino) diphenylsulfone, (Diamino) benzophenone, (3,3'-diamino) benzophenone, (4,4'-diamino) diphenylmethane, (4,4'-diamino) '- Dia And aromatic diamines such as hexamethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, octadecamethylenediamine, 4,4'-methylenebis (cyclohexylamine), iso Aliphatic diamines such as phthalic anhydride, peronediamine, 1,4-cyclohexanediamine and norbornenediamine.

The polyamideimide resin may have a structure represented by the following general formula (ii).

Where Z may be an aliphatic or aromatic containing moiety. When it is an aliphatic group, it may contain an alicyclic group such as a cyclohexane ring. According to the production method described later, Z is a residue of the diisocyanate compound (e).

The method for producing the polyamide-imide resin is not limited, and can be prepared by an imidization process and an amidimidation process using a known process.

In the imidization step, the diamine diamine (a), the carboxyl group-containing diamine (b), and the cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) and the trimellitic anhydride Is reacted to obtain an imide.

The amount of the dimer diamine (a) is preferably such that the content of the dimer diamine (a) is 20 to 60 mass%, and the content of the dimer diamine (a) is preferably 30 to 50 mass%. The definition of the content of the dimer diamine (a) is as described above.

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

From the viewpoint of increasing the alkali solubility of the polyamide-imide resin, it is preferable to use cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) in the imidation step. The molar ratio of the amount of the cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) to the amount of the anhydrous trimellitic acid (d) used is preferably 85/15 to 100/0 , More preferably 90/10 to 99/1, and even more preferably 90/10 to 98/2.

Means diamine compound (B) (specifically, dimer diamine (a) and carboxyl group-containing diamine (b) used for obtaining imide cargo (A) and other diamine (f) (C) (specifically, one kind selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) and trimellitic anhydride Or two species) is not limited. The amount of the acid anhydride (C) to be used is preferably such that the molar ratio with respect to the amount of the diamine compound (B) is 2.0 or more and 2.4 or less, more preferably 2.0 or more and 2.2 or less.

In the amidimidation step, a diisocyanate compound (e) is reacted with the imide (A) obtained by the imidation process to form a polyamideimide resin (B) containing a substance having a structure represented by the following general formula .

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

Specific examples of the diisocyanate compound (e) include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o- Aromatic diisocyanates such as randy isocyanate, m-xylylene diisocyanate and 2,4-tolylene dimer; And aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and norbornene diisocyanate. From the viewpoint that both the alkali solubility of the polyamide-imide resin and the light transmittance of the polyamide-imide resin are both good, the diisocyanate compound (e) preferably contains an aliphatic isocyanate and the diisocyanate compound (e) is an aliphatic isocyanate More preferable.

The amount of the diisocyanate compound (e) used in the amideimidation step is not limited. The amount of the diisocyanate compound (e) to be used is preferably from 0.3 to 1.0 (molar ratio) to the amount of the diamine compound (B) used for obtaining the imide compound (A) from the viewpoint of imparting suitable alkali solubility to the polyamide- Or less, more preferably 0.4 or more and 0.95 or less, and particularly preferably 0.50 or more and 0.90 or less.

The polyamide-imide resin thus produced contains 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 residue of the diisocyanate compound (e). n is a natural number.

(Curable compound)

The curable resin composition of the present invention further comprises a curable compound. As the curable compound, a known compound having a functional group capable of curing reaction by heat or light is used. For example, a photo-curable compound having a functional group capable of curing by light such as a thermosetting compound having a functional group capable of curing reaction by heat such as a cyclic (thio) ether group or an ethylenically unsaturated double bond group, It is preferable to use a thermosetting compound, particularly an epoxy resin.

Examples of the epoxy resin include bisphenol A type epoxy resin, brominated epoxy resin, novolak type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, Hidantoin type epoxy resin, alicyclic epoxy Resin, trihydroxyphenylmethane type epoxy resin, biquileneol type or biphenol type epoxy resin, or a mixture thereof; Bisphenol S type epoxy resin, bisphenol A novolak type epoxy resin, heterocyclic epoxy resin, biphenyl novolak type epoxy resin, naphthalene group containing epoxy resin, and epoxy resin having dicyclopentadiene skeleton.

Particularly, when a thermosetting compound is used, the thermosetting compound has an equivalent ratio (alkali soluble group such as carboxyl group: thermosetting group such as epoxy group) with an alkali soluble resin (polyimide resin, polyamideimide resin, etc.) : ≪ / RTI > 10. When the blend ratio is set at such a ratio, the developability becomes good, and a fine pattern can be easily formed. The above-mentioned equivalent ratio is more preferably 1: 0.2 to 1: 5.

(Core shell rubber particles)

The curable resin composition of the present invention preferably further contains core-shell rubber particles. Thus, it is possible to provide a curable resin composition which is excellent in developability and heat resistance, suitable for use as an insulating film for electronic components such as flexible printed wiring boards, and satisfies required performance of both solder resists and coverlay, for example .

The core-shell rubber particles constituting the curable resin composition of the present invention have a function of improving the flexibility by the core-shell rubber particles without deteriorating the adhesion.

The core shell rubber particles refer to a rubber material having a multi-layer structure composed of a core layer having a different composition and at least one shell layer covering the core layer. The core shell rubber particles can be obtained by forming the core layer with a material having excellent flexibility and the shell layer with a material having excellent affinity for other components as described later, The dispersibility becomes good.

According to the characteristic combination configuration of the present invention in which such core-shell rubber particles are compounded, it is possible to provide a cured product having excellent flexibility free from occurrence of cracks or the like in an excessive bending test even under heat treatment such as reflow A specific effect which is not present in the conventional art can be exhibited.

As the constituent material of the core layer, a material excellent in flexibility is used. Specific examples include silicone-based elastomers, butadiene-based elastomers, styrene-based elastomers, acrylic elastomers, polyolefin-based elastomers, and silicone / acrylic composite-based elastomers.

On the other hand, as the constituent material of the shell layer, a material having excellent affinity for other components is 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 an epoxy resin. More preferably, it is an acrylic resin or an epoxy resin.

Such core-shell rubber particles preferably have a curing reactive group on the surface from the viewpoint of storage stability, and such a curable reactive group contributes to the thermosetting reaction and contributes to the photo-curable reaction. In addition, the core shell rubber particles may have two or more curable reactors.

Examples of the thermosetting reactor include a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group and an oxazoline group. More preferably an epoxy group.

Examples of the photocurable reactors include a vinyl group, a styryl group, a methacrylic group, and an acrylic group. Even when the content of the filler is large, it is preferable that the methacrylic group and the acrylic group are included because the reactivity becomes appropriate.

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

Commercially available products of core-shell rubber particles include Paraloid ELX 2655 manufactured by Rohm and Haas, and XER-91 manufactured by Nippon Gosei Rubber Co., Ltd.

In the curable resin composition of the present invention, the core-shell rubber particles preferably have an average particle diameter of 2 탆 or less from the viewpoint of excellent crack resistance. More preferably 0.01 to 1 mu m. In the present specification, the average particle diameter is a value of D50 measured by a microtrack 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 based on the organic component in the solid content in the composition. If it is 1% by mass or more, it is preferable from the viewpoint of excellent crack resistance. On the other hand, if it is 30% by mass or less, it is preferable from the standpoint of excellent printability and developability. And more preferably 3 to 20 mass%. The curable resin composition of the present invention may contain core shell rubber particles having a curable reactor and core shell rubber particles not having a curable reactor. Here, the organic component means a solid whole component other than an inorganic component such as a filler.

(Photopolymerization initiator)

When the curable resin composition of the present invention is made of a photosensitive resin composition, it preferably contains a photopolymerization initiator. As the photopolymerization initiator, a known photopolymerization initiator can be used. In particular, when the curable resin composition of the present invention is applied to a PEB process after light irradiation described later, it is preferable to use a photopolymerization initiator having a function as a photobase generator . In this PEB step, a photopolymerization initiator and a photobase generator may be used in combination.

A photopolymerization initiator having a function as a photobase generator is a photopolymerization initiator which is capable of functioning as a catalyst for polymerization reaction of a thermosetting compound which is a curing compound by changing the molecular structure by irradiation of light such as ultraviolet rays or visible light, Or more basic substance. As the basic substance, for example, secondary amine and tertiary amine can be mentioned.

Examples of the photopolymerization initiator having a function as a photobase generator include, for example, an? -Aminoacetophenone compound, an oxime ester compound, an acyloxyimino group, an N-formylated aromatic amino group, a N-acylated aromatic amino group, And a compound having a substituent such as a methoxy group, a methoxy group or an alkoxybenzyl carbamate group. Of these, oxime ester compounds and? -Amino acetophenone compounds are preferable, and oxime ester compounds are more preferable. As the? -amino acetophenone compound, those having at least two nitrogen atoms are particularly preferred.

The? -amino acetophenone compound may be any one that has a benzoin ether bond in its molecule and undergoes cleavage in the molecule upon irradiation with light to generate a basic substance (amine) exhibiting a curing catalytic action.

As the oxime ester compound, any compound capable of generating a basic substance by light irradiation can be used.

One such photopolymerization initiator may be used alone, or two or more photopolymerization initiators may be used in combination. The blending amount of the photopolymerization initiator in the resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.3 to 15 parts by mass based on 100 parts by mass of the total amount of the alkali soluble resin. When the amount is not less than 0.1 part by mass, the contrast of the developability of the light irradiation portion / the non-irradiation portion can be satisfactorily obtained. When the amount is 40 parts by mass or less, the properties of the cured product are improved.

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

(Polymer resin)

The curable resin composition of the present invention can be blended with a publicly known polymer resin for the purpose of improving flexibility and tack dryness of the obtained cured product. Examples of such a polymer resin include cellulose-based, polyester-based, and phenoxy resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based, polyamideimide-based binder polymers and elastomers. These polymer resins may be used alone or in combination of two or more.

(Inorganic filler)

The curable resin composition of the present invention may contain an inorganic filler in order to suppress curing shrinkage of the cured product and to improve properties such as adhesion and hardness. Examples of the inorganic filler include inorganic fillers such as barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, .

(coloring agent)

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

(Organic solvent)

The curable resin composition of the present invention can be blended with an organic solvent for the production of a resin composition or for viscosity adjustment for application to a substrate or a carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents and the like. These organic solvents may be used singly or as a mixture of two or more kinds.

(Other components)

If necessary, the curable resin composition of the present invention can further contain components such as a mercapto compound, an adhesion promoter, a thermosetting catalyst, an antioxidant, and an ultraviolet absorber. These can be used for known purposes.

It is also possible to add known additives such as thickening agents for known additives such as fine silica, hydrotalcite, organic bentonite and montmorillonite, antifoaming agents such as silicone, fluorine and high molecular weight and / or leveling agents, silane coupling agents and rust preventive agents .

The curable resin composition of the present invention including the above-described constitution is characterized in that it comprises a resin layer (A) to be described later and a laminate structure having a resin layer (B) to be laminated on the flexible printed wiring board via the resin layer The resin layer (B) can be suitably used.

(Laminated structure)

The laminated structure of the present invention has a resin layer (A) and a resin layer (B) laminated on a substrate such as a flexible printed wiring board via a resin layer (A).

Here, in the laminated structure of the present invention, each of the resin layer (A) and the resin layer (B) functions substantially as an adhesive layer and a protective layer. The laminated structure of the present invention is characterized in that the resin layer (B) comprises the above-mentioned curable resin composition and the resin layer (A) comprises an alkali-developable resin composition comprising an alkali-soluble resin and a thermoreactive compound Respectively.

In the present invention, by providing the resin layer (B) on the upper layer side of the laminated structure in which two resin layers are laminated, the excellent heat resistance can be realized without deteriorating developability . Further, by using a polyamide-imide resin as an alkali-soluble resin other than the polyimide resin, it is possible to provide excellent heat resistance and low repulsion without deteriorating developability, and to reduce warp after heating. By containing 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 and heat resistance, and particularly excellent flexibility after solder reflow. When the core-shell rubber particles are contained in the resin layer (A) on the lower layer side of the laminated structure, there is a fear that the adhesiveness is lowered. However, the resin layer (B) It is possible to obtain the effect of improving flexibility by the core-shell rubber particles without deteriorating the adhesion. Therefore, in the present invention, it is preferable that no core shell rubber particles are contained in the resin layer (A).

[Resin Layer (A)]

(Alkali developing type resin composition)

The alkali-developable resin composition constituting the resin layer (A) may be an alkali-soluble resin and a resin composition which can be developed into an alkali solution containing a heat-reactive compound. Preferable examples of the alkali-soluble resin include a resin composition containing a compound having a phenolic hydroxyl group, a compound having a carboxyl group, a compound having a phenolic hydroxyl group and a carboxyl group, and a known one is used.

For example, a resin composition containing a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin, a compound having an ethylenic unsaturated bond, and a heat-reactive compound, which have been conventionally used as a solder resist composition, can be mentioned.

Here, as the compound having a carboxyl group-containing resin or a carboxyl group-containing photosensitive resin and a compound having an ethylenically unsaturated bond, a known compound is used, and as the heat-reactive compound, a functional group capable of curing reaction by heat such as a cyclic (thio) ≪ / RTI > is used.

The resin layer (A) may or may not contain a photopolymerization initiator. Examples of the photopolymerization initiator used when the photopolymerization initiator includes the photopolymerization initiator include the same ones as the photopolymerization initiator used in the above-mentioned curable resin composition .

The resin layer (A) may contain other components similar to the above-mentioned curable resin composition, such as a polymer resin, an inorganic filler, a colorant, and an organic solvent.

[Resin Layer (B)]

The resin layer (B) is formed of a curable resin composition containing the aforementioned alkali soluble polyimide resin, other alkali soluble resin and a curable compound, and the other points are not particularly limited .

As the alkali soluble polyimide resin, other alkali soluble resins, and curable compounds, resins and compounds similar to those constituting the curable resin composition of the present invention can be used.

The curable resin composition constituting the resin layer (B) is preferably an alkali-soluble resin other than the polyimide resin, more preferably a polyamideimide resin, more preferably a polyamideimide resin represented by the general formula (1) And a polyamide-imide resin having a structure represented by the general formula (2). By such a constitution, it is possible to obtain a resin composition having excellent properties such as flex resistance and heat resistance without deteriorating developability.

The laminated structure of the present invention can be used for at least one of the bent portion and the non-bent portion of an electronic component such as a flexible printed wiring board because of its excellent flexibility. For example, the cover layer of a flexible printed wiring board, And can be used as at least one of the materials.

The laminated structure of the present invention having the above-described constitution is preferably used as a dry film in which at least one side thereof is supported or protected by a film.

(Dry film)

The dry film can be produced, for example, as follows.

That is, first, the curable resin composition constituting the resin layer (B) and the alkali developing resin composition constituting the resin layer (A) are each diluted with an organic solvent on a carrier film (support film) And the coating is sequentially applied by a known method such as a comma coater according to a conventional method. Thereafter, it is usually dried at a temperature of 50 to 130 ° C for 1 to 30 minutes to prepare a dry film on which a coating film of the resin layer (B) and the resin layer (A) is formed on the carrier film. On the dry film, a peelable cover film (protective film) can be laminated for the purpose of preventing dust from adhering to the surface of the coated film. As the carrier film and the cover film, a conventionally known plastic film can be suitably used, and it is preferable that the cover film is smaller than the adhesive force between the resin layer and the carrier film when the cover film is peeled off. The thickness of the carrier film and the cover film is not particularly limited, but is generally appropriately selected in the range of 10 to 150 mu m.

(Hard goods)

The cured product of the present invention is obtained by curing the above-mentioned curable resin composition of the present invention or the above-described laminated structure of the present invention.

(Electronic parts)

INDUSTRIAL APPLICABILITY 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, a flexible printed wiring board or the like having a cured product of an insulating film formed by forming a layer of a curable resin composition or a laminated structure of the present invention on a flexible printed wiring substrate, patterning the layer by light irradiation, .

Hereinafter, as an example of an electronic component, a manufacturing method of a flexible printed wiring board will be described in detail.

(Manufacturing Method of Flexible Printed Circuit Board)

The production of the flexible printed wiring board using the laminated structure of the present invention can be performed, for example, according to the procedure shown in the process chart of Fig. That is, a step (laminating step) of forming a layer of the laminated structure of the present invention on a flexible printed wiring board on which a conductor circuit is formed, a step (an exposure step) of irradiating the layer of this laminated structure with a pattern of active energy rays, And a step of developing the layer of the laminated structure by alkali to form a layer of the patterned laminated structure (developing step). If necessary, after the alkali development, further photo-curing or thermosetting (post-curing step) is carried out to completely cure the layer of the laminated structure, whereby a highly reliable flexible printed wiring board can be obtained.

The production of the flexible printed wiring board using the laminated structure of the present invention can also be carried out, for example, according to the procedure shown in the process chart of Fig. That is, a step (laminating step) of forming a layer of the laminated structure of the present invention on a flexible printed wiring board on which a conductor circuit is formed, a step (an exposure step) of irradiating the layer of this laminated structure with a pattern of active energy rays, A step of heating the layer of the laminated structure (a heating (PEB) step), and a step of developing the layers of the laminated structure by alkali to form a layer of the patterned laminated structure (developing step). If necessary, after the alkali development, further photo-curing or thermosetting (post-curing step) is carried out to completely cure the layer of the laminated structure, whereby a highly reliable flexible printed wiring board can be obtained.

Hereinafter, each step in FIG. 1 or FIG. 2 will be described in more detail.

[Lamination step]

In this step, a resin layer 3 (resin layer (A)) of an alkali developing resin composition including an alkali soluble resin or the like and a resin layer 3 (a resin layer) are formed on a flexible printed wiring board 1 on which a conductor circuit 2 is formed. (Resin layer (B)) of the curable resin composition of the present invention on a substrate (not shown). Here, each of the resin layers constituting the laminated structure is formed by, for example, applying resin compositions constituting the resin layers 3 and 4 to the wiring substrate 1 sequentially and drying the resin layers 3 and 4 Alternatively, the resin composition constituting the resin layers 3 and 4 may be formed in the form of a dry film of a two-layer structure by a method of laminating the wiring substrate 1.

The method of applying the resin composition to the wiring substrate may be a known method such as a blade coater, a lip coater, a comma coater, and a film coater. The drying method includes a method in which warm air in a dryer is countercurrently contacted by using a hot-air circulating drying furnace, an IR, a hot plate, a convection oven, or the like, Or a known method such as a spraying method.

[Exposure step]

In this step, the photopolymerization initiator contained in the resin layer 4 is activated in a negative pattern by irradiation of an active energy ray to cure the exposed portion. In the case of a composition using a PEB process, which will be described later, a photopolymerization initiator having a function as a photobase generator or a photobase generator is activated in a negative pattern to generate a base.

The exposure apparatus used in this process may be a direct imaging apparatus, an exposure apparatus equipped with a metal halide lamp, or the like. The pattern-like exposure mask is a negative type mask.

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

[PEB process]

In this step, after exposure, the resin layer is heated to cure the exposed portion. By this step, a photopolymerization initiator having a function as a photopolymerization initiator can be used, or a base generated in the exposure step of the resin layer (B) including a composition comprising a photopolymerization initiator and a photo- B) to the core. The heating temperature is, for example, 70 to 150 ° C. The heating time is, for example, 1 to 120 minutes. Since the resin composition in the present invention is a ring-opening reaction of an epoxy resin by, for example, a thermal reaction, deformation and curing shrinkage can be suppressed as compared with the case where curing proceeds in a photo radical reaction.

[Development process]

In this step, the unexposed portion is removed by alkali development to form a negative patterned insulating film, for example, a coverlay and a solder resist. As a developing method, a known method such as dipping can be used. As the developer, an aqueous alkali solution such as sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, aqueous solution of tetramethylammonium hydroxide (TMAH), or a mixture thereof may be used.

[Post-curing process]

Further, after the development step, the insulating film may be further irradiated with light or may be heated, for example, at 150 DEG C or higher.

<Examples>

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

(Synthesis Example 1)

28.61 g (0.052 mol) of an aliphatic diamine (product name: PRIAMINE1075, manufactured by Kuroda Japan Co., Ltd.) derived from dimer acid having a carbon number of 36 as a dimer diamine (a), 0.5 g of a carboxyl group (0.028 mol) of 3,5-diaminobenzoic acid as a diamine (b) and 85.8 g of? -Butyrolactone were dissolved and dissolved at room temperature.

Subsequently, 30.12 g (0.152 mol) of cyclohexane-1,2,4-tricarboxylic acid anhydride (c) and 3.07 g (0.016 mol) of anhydrous trimellitic acid (d) were added and kept at room temperature for 30 minutes. Further, 30 g of toluene was charged, and the temperature was raised to 160 ° C to remove water generated with toluene, and then the mixture was kept for 3 hours and cooled to room temperature to obtain a solution containing imide.

14.30 g (0.068 mol) of trimethylhexamethylene diisocyanate as the diisocyanate compound (e) was added to a solution containing the obtained imide compound, and the mixture was kept at 160 ° C. for 32 hours and diluted with 21.4 g of cyclohexanone Thereby obtaining a solution (A-1) containing a polyamide-imide resin. The mass average molecular weight Mw of the obtained polyamide-imide resin was 5250, the solid content was 41.5% by mass, the acid value was 63 mgKOH / g, and the content of the dimer diamine (a) was 40.0% by mass.

(Synthesis Example 2)

29.49 g (0.054 mol) of an aliphatic diamine (product name: PRIAMINE1075, manufactured by Kuroda Japan Co., Ltd.) derived from dimer acid having a carbon number of 36 as a dimer diamine (a) was added to four 300 mL flasks equipped with a nitrogen gas introducing tube, a thermometer and a stirrer, 4.02 g (0.026 mol) of 3,5-diaminobenzoic acid as the diamine (b) and 73.5 g of? -Butyrolactone were dissolved and dissolved at room temperature.

Subsequently, 31.71 g (0.160 mol) of cyclohexane-1,2,4-tricarboxylic acid anhydride (c) and 1.54 g (0.008 mol) of anhydrous trimellitic acid (d) were added and kept at room temperature for 30 minutes. Further, 30 g of toluene was charged, and the temperature was raised to 160 ° C to remove the water produced with toluene, and then the mixture was kept for 3 hours and cooled to room temperature to obtain a solution containing the imide.

6.90 g (0.033 mol) of trimethylhexamethylene diisocyanate and 8.61 g (0.033 mol) of dicyclohexylmethane diisocyanate as a diisocyanate compound (e) were fed into a solution containing the obtained imide cargo, For 32 hours, and diluted with 36.8 g of cyclohexanone to obtain a solution (A-2) containing the polyamideimide resin. The mass average molecular weight Mw of the obtained polyamide-imide resin was 5840, the solid content was 40.4% by mass, the acid value was 62 mgKOH / g, and the content of the dimer diamine (a) was 40.1% by mass.

(Synthesis Example 3)

To a four-necked 300 mL flask equipped with a nitrogen gas introducing tube, a thermometer and a stirrer were added 6.98 g of 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 3.80 g of 3,5-diaminobenzoic acid, 8.21 g of diamine (manufactured by Huntsman, product name: Elastamine RT1000, molecular weight 1025.64) and 86.49 g of? -Butyrolactone were dissolved at room temperature.

Subsequently, 17.84 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and 2.88 g of trimellitic anhydride were added and kept at room temperature for 30 minutes. Further, 30 g of toluene was charged, the temperature was raised to 160 캜, water produced together with toluene was removed, and the mixture was kept for 3 hours and cooled to room temperature to obtain an imide freed solution.

9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were added to the resulting imide cargo solution, and the mixture was kept at 160 ° C for 32 hours. Thus, a polyamide-imide 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)

In a separable three-necked flask equipped with a stirrer, a nitrogen introducing tube, a separating ring and a cooling ring, 22.4 g of 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone, 8.2 g of 4- (4-aminophenoxy) phenyl] propane, 30 g of NMP, 30 g of? -Butyrolactone, 27.9 g of 4,4'-oxydiphthalic anhydride and 3.8 g of trimellitic anhydride, , And the mixture was stirred at room temperature and 100 rpm for 4 hours. Subsequently, 20 g of toluene was added, and the mixture was stirred for 4 hours while distilling toluene and water at a silicon bath temperature of 180 ° C and 150 rpm to obtain a polyimide resin solution (PI-1) having a phenolic hydroxyl group and a carboxyl group.

The obtained resin (solid content) had an acid value of 18 mgKOH, an Mw of 10,000 and a hydroxyl group equivalent of 390.

(Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2)

The materials described in Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 were mixed in accordance with the composition shown in Table 1, premixed in an agitator, kneaded in a three-roll mill, To prepare respective resin compositions for forming a resin layer. The values in the table are parts by mass of solid content, unless otherwise specified.

* 1-1) Polyamideimide resin-containing solutions (A-1) to (A-3): Synthesis Examples 1 to 3

* 1-2) Alkali-soluble resin (PI-1): Synthesis Example 4

* 1-3) Photopolymerization initiator: Oxime photopolymerization initiator IRGACURE OXE02 (BASF)

* 1-4) Epoxy resin: bisphenol A type epoxy resin E828, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

&Lt; Formation of resin layer >

A flexible printed wiring board on which a circuit with a copper thickness of 18 mu m was formed was prepared, and preprocessing was carried out using MacCax CZ-8100. Thereafter, the respective resin compositions obtained in Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 were applied to the pretreated flexible printed wiring board so that the film thickness after drying was 30 占 퐉. Thereafter, the resultant was dried in a hot-air circulating type drying oven at 90 DEG C for 30 minutes to form an uncured resin layer.

<Developability (Alkali Solubility)>

(HMW-680-GW20) equipped with a metal halide lamp was used for the uncured resin layer on each of the flexible printed wiring boards on which the resin layer was formed as described above, Cm &lt; 2 &gt; to form an opening having a diameter of 200 mu m. The substrate having the resin layer after exposure was subjected to heat treatment at 90 占 폚 for 30 minutes. Subsequently, the substrate was immersed in an aqueous 1% by mass aqueous solution of sodium carbonate at 30 ° C and developed for 1 minute, and the state of pattern formation was observed to evaluate developability (alkali solubility). The evaluation criteria are as follows.

?: Developability in the exposed portion, developability in the unexposed portion, good pattern formation

X: The unexposed area shows developability, but the resolution pattern formation is poor (insufficient resolution)

&Lt; Heat resistance (solder heat resistance) >

(Preparation of Evaluation Substrate)

(HMW-680-GW20) equipped with a metal halide lamp was used for the uncured resin layer on each of the flexible printed wiring boards on which the resin layer was formed as described above, Cm &lt; 2 &gt; to form an opening having a diameter of 200 mu m. Then, after performing PEB for 30 minutes at 90 ℃ process, the developer is performed (30 ℃, 0.2MPa, 1 wt% Na ₂ CO ₃ aqueous solution) is 60 seconds, number of cured by heat-curing to 150 ℃ × 60 minutes, and resin layer A flexible printed wiring board (evaluation board) was produced.

(Assessment Methods)

The rosin-based flux was applied to the evaluation substrate prepared as described above, and the roughened flux was immersed in a solder bath set at 260 캜 for 20 seconds (10 seconds × 2 times) to expand and peel the cured coating film (resin layer) And the heat resistance (solder heat resistance) was evaluated by observation. The evaluation criteria are as follows.

○: No swelling or peeling occurred even after 10 seconds × 2 times of immersion

X: Expansion / peeling occurred when the substrate was submerged for 10 seconds × 1 time

&Lt; Chemical resistance (gold plating resistance) >

Using the same evaluation board as that for evaluating the heat resistance, evaluation was made by the following method.

The evaluation substrate was plated with nickel of 5 탆 and gold of 0.05 탆 at 80 to 90 캜 using commercially available electroless nickel plating baths and electroless gold plating baths and the substrate and resin layers were observed to determine the chemical resistance (Gold plating resistance). The evaluation criteria are as follows.

○: There is no seepage between the substrate and the coating film (resin layer)

?: Seepage between the substrate and the coating film (resin layer) is confirmed

X: Peeling occurred in a part of the coating film (resin layer)

<Resilience (Spring People)>

(Preparation of test piece)

The respective resin compositions obtained in Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 were coated on a polyimide film so that the film thickness after drying was 30 占 퐉, and in the hot air circulation type drying furnace, 90 Lt; 0 &gt; C for 30 minutes to form an uncured resin layer. Thereafter, using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, exposure was performed at 300 mJ / cm 2 without interposing a mask. Then, after subjected to PEB process at 90 ℃ 30 minutes, and developing (30 ℃, 0.2MPa, 1 wt% Na ₂ CO ₃ solution) is performed by the 60 seconds, the curing heat to 150 ℃ × 60 minutes, not be cured A polyimide film test piece having a stratified layer was prepared.

(Assessment Methods)

The polyimide film test piece prepared as described above was cut into 2 cm x 7 cm, both ends of the long side were aligned to be a band-like ring, and the both ends of the polyimide film test piece were fixed to the electronic balance with a tape. The repulsive force (springiness) was measured by measuring the load when the ring was pressed with a glass plate so that the distance between the upper and lower portions of the ring was 3 mm in the warped state, as the repulsive force (g). The evaluation criteria are as follows.

○: less than 30 g

?: 30 g or more and less than 45 g

×: 45 g or more

&Lt; Flexure after curing >

Using the same test piece as that of the rebound test, the evaluation was made by the following method.

The specimens were cut into 5 cm × 5 cm, and then the substrate was placed on a horizontal test stand with the side up. Then, the distance from the test point to each of the four vertices was measured to 1 mm square. , And the flexural strength after curing was evaluated. The evaluation criteria are as follows.

○: deflection less than 3 mm

?: Deflection 3mm or more and less than 6mm

X: deflection 6mm or more

The evaluation results are shown in Table 2.

(Examples 1-10 to 1-12)

The materials described in Examples 1-10 to 1-12 were each compounded according to the composition shown in Table 3, preliminarily mixed in a stirrer, and kneaded with a three-roll mill to prepare an angle for forming the resin layer (A) Each resin composition for forming the resin composition and the resin layer (B) was prepared. The values in the table are parts by mass of solid content, unless otherwise specified.

* 1-1) Polyamideimide resin-containing solutions (A-1) to (A-3): Synthesis Examples 1 to 3

* 1-2) Alkali-soluble resin (PI-1): Synthesis Example 4

* 1-3) Photopolymerization initiator: Oxime photopolymerization initiator IRGACURE OXE02 (BASF)

* 1-4) Epoxy resin: bisphenol A type epoxy resin E828, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

* 1-5) Alkali-soluble resin: P7-532: Polyurethane acrylate, acid value 47 mgKOH / g (manufactured by Kyoeisha Chemical Co., Ltd.)

* 1-6) Photopolymerizable monomer: BPE-500: ethoxylated bisphenol A dimethacrylate (manufactured by Shin Nakamura Kagaku Co., Ltd.)

&Lt; Formation of Resin Layer (A) >

A flexible printed wiring board on which a circuit with a copper thickness of 18 mu m was formed was prepared, and preprocessing was carried out using MacCax CZ-8100. Thereafter, the respective resin compositions for forming the resin layer (A) obtained in Examples 1-10 to 1-12 were coated on the flexible printed wiring board subjected to the pretreatment so as to have a thickness after drying of 20 m. Thereafter, the resultant was dried in a hot air circulating type drying oven at 90 DEG C for 30 minutes to form a resin layer.

&Lt; Formation of resin layer (B) >

Resin compositions for forming the resin layer (B) obtained in each of Examples 1-10 to 1-12 were coated on the resin layer (A) formed above in such a manner that the film thickness after drying was 10 mu m. Thereafter, the resultant was dried in a hot air circulating type drying oven at 90 DEG C for 30 minutes to form a resin layer (B).

Thus, a non-cured laminated structure including the resin layer (A) and the resin layer (B) described in Examples 1-10 to 1-12 was formed on the flexible printed wiring board.

The uncured laminated structure formed as described above was evaluated for the uncured resin layers in Examples 1-1 to 1-9 and Comparative Examples 1-1 and 1-2 by the same method .

The evaluation results are shown in Table 4.

As is clear from the evaluation results shown in Tables 2 and 4, it was confirmed that the resin composition of each of the Examples had excellent developability, heat resistance, low rebound, and low warpability after heating.

(Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2-2)

The materials described in Examples 2-1 to 2-5 and Comparative Examples 2-1 and 2-2 were each compounded according to the composition shown in Table 5, premixed in an agitator, kneaded in a three-roll mill, A resin composition for forming each resin layer was prepared. The values in the table are parts by mass of solid content, unless otherwise specified.

* 2-1) Alkali-soluble resin 1 (PI-1): Synthesis Example 4

* 2-2) Alkali-soluble resin 2: carboxyl group-containing epoxy acrylate ZAR-1035 (acid value: 98 mgKOH / g, manufactured by Nippon Kayaku Co., Ltd.)

* 2-3) Solution containing polyamideimide (A-1): Synthesis Example 1

* 2-4 Oxime photopolymerization initiator: IRGACURE OXE02 (BASF)

* 2-5) Epoxy resin: Bisphenol A type epoxy resin E828, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

* 2-6) Core shell polymer 1: Paraloid EXL-2655 (manufactured by Rohm and Haas)

* 2-7) Core shell polymer 2: Staphyloid AC-3355 (manufactured by Kanto Chemical Industry Co., Ltd.)

* 2 - 8) Master batch 1 comprising core shell polymer 1: ("ARALITE (registered trademark)" MY721: 75 mass% / core shell polymer particle A (volume average particle diameter: 100 nm, core part: butadiene / styrene 25% by mass of a master batch), and core shell polymer particles A were prepared according to Japanese Patent Laid-Open Publication No. 2005 -248109. &Lt; tb &gt; &lt; TABLE &gt; However, the ratio of butadiene / styrene was 50% by mass / 50% by mass. After the butadiene-styrene rubber latex was prepared, 5% by mass / 5% by mass / 5% by mass of methyl methacrylate / glycidyl methacrylate / styrene relative to 100% by mass of the butadiene- And graft polymerization was carried out.

* 2-9) Acrylate resin: ethoxylated bisphenol A dimethacrylate BPE-900 (manufactured by Shin Nakamura Kagaku Co., Ltd.)

&Lt; Formation of Resin Layer (A) >

A flexible printed wiring board on which a circuit with a copper thickness of 18 mu m was formed was prepared, and preprocessing was carried out using MacCax CZ-8100. Thereafter, the resin compositions constituting each of the resin layers (A) obtained in Examples 2-1 to 2-4 and Comparative Examples 2-1 and 2-2 were applied to the prepreg-processed flexible printed wiring substrate, Was 25 mu m. Thereafter, the resultant was dried in a hot air circulating type drying oven at 90 DEG C for 30 minutes to form a resin layer (A).

&Lt; Formation of resin layer (B) >

The resin compositions constituting each of the resin layers (B) obtained in Examples 2-1 to 2-4 and Comparative Examples 2-1 and 2-2 were formed on the resin layer (A) Mu] m. Thereafter, the resultant was dried in a hot air circulating type drying oven at 90 DEG C for 30 minutes to form a resin layer (B).

Thus, the uncured laminated structure including 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 was formed on the flexible printed wiring board Respectively.

<Developability (Alkali Solubility)>

First, an uncured laminated structure on each flexible printed wiring substrate on which a laminated structure was formed was exposed to light at 500 mJ / cm 2 through a negative mask using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp first, Cm &lt; 2 &gt; to form an opening having a diameter of 200 mu m. The substrate having the uncured laminated structure after exposure was subjected to heat treatment at 90 占 폚 for 30 minutes. Subsequently, the substrate was immersed in a 1% by mass aqueous solution of sodium carbonate at 30 ° C and developed for 1 minute to evaluate whether or not an opening of 200 μm pattern was formed. The evaluation criteria are as follows.

?: Developability in the exposed portion, developability in the unexposed portion, good pattern formation

?: The unexposed area shows developability, but the developing property of the exposed area is insufficient, and the pattern can not be formed

X: Pattern can not be formed because the unexposed portion is not dissolved in the developing solution

<Heat resistance>

First, an uncured laminated structure on each flexible printed wiring substrate on which a laminated structure was formed was exposed to light at 500 mJ / cm 2 through a negative mask using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp, Cm &lt; 2 &gt; to form an opening having a diameter of 200 mu m. Then, after performing PEB for 30 minutes at 90 ℃ step, developing (30 ℃, 0.2MPa, 1 wt% Na ₂ CO ₃ solution) is performed by the 60 seconds, the curing heat to 150 ℃ × 60 minutes, the cured laminate structure A flexible printed wiring board (evaluation board) was produced. The rosin-based flux was applied to the evaluation substrate and immersed in a solder bath set at 260 占 폚 for 20 seconds (10 seconds 占 2 times) to evaluate expansion / exfoliation of the cured coating film. The evaluation criteria are as follows.

○: No swelling or peeling occurred even after 10 seconds × 2 times of immersion

X: Expansion / peeling occurred when the substrate was submerged for 10 seconds × once, and the adhesion was insufficient

&Lt; Flexibility (Bending test after 260 占 폚 solder reflow)

The evaluation board was passed through a reflow furnace set at a maximum temperature of 260 占 폚 three times in advance, and the bending property was evaluated by the following test method.

The test piece was folded at 180 ° so as to be outside of the cured coating film, folded and loaded by a load G (standard weight of 1 kg) sandwiched between two flat plates for 10 seconds and then folded using a light microscope, The operation of confirming whether or not a crack occurred in the portion was set as one cycle, and the number of times before cracking was recorded. The evaluation criteria are as follows.

◎: Bending more than 20 times

○: Bending 10 times or more and less than 20 times

B: Bending more than 5 times and less than 10 times

X: Less than 5 times bending

The evaluation results are shown in Table 6.

As is clear from the evaluation results shown in the above table, it was confirmed that in the laminated structure of each example, good flexibility was obtained even after solder reflow, in addition to excellent developability and heat resistance.

Subsequently, the resin composition constituting the resin layer (B) of Example 2-5 was coated on the flexible printed wiring board on which a circuit with a copper thickness of 18 mu m was formed in the same manner as the formation of the resin layer (B) . The obtained coating film was evaluated for the above-mentioned resolution, heat resistance, and flexibility. The evaluation results are shown in Table 7.

1: Flexible printed wiring board
2: conductor circuit
3: Resin layer
4: Resin layer
5: Mask

Claims (10)

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 polyamideimide resin. The curable resin composition according to claim 2, wherein the polyamideimide resin is a polyamideimide resin having a structure represented by the following formula (1) and a structure represented by the following formula (2).

(X ₁ is a residue of an aliphatic diamine (a) 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, and Y is each independently a cyclohexane ring or an 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 polyimide 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 having a resin layer (A) and a resin layer (B) laminated on the substrate via the resin layer (A)
Wherein the resin layer (B) comprises the curable resin composition according to any one of claims 1 to 7, and the resin layer (A) is an alkali developing type resin containing an alkali soluble resin and a thermoreactive compound A laminated structure comprising a resin composition. A cured product comprising the curable resin composition according to any one of claims 1 to 7 or the laminated structure according to claim 8. An electronic part having an insulating film containing the cured product according to claim 9.

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