JP7248682B2 - Curable resin composition, dry film, cured product, and printed wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curable resin composition, a dry film, a cured product, and a printed wiring board.

In recent years, the spread of smartphones and tablet terminals and the improvement in their performance are progressing rapidly. Consumer demands for miniaturization and thinning of information equipment terminals represented by these are high, and in order to meet such demands, it is necessary to increase the density and space saving of the circuit board inside the product. Therefore, the use of flexible printed wiring boards, which can be folded and stored and can increase the degree of freedom in circuit layout, is expanding, and flexible printed wiring boards with higher reliability than ever before are in demand. there is
Printed wiring board manufacturing processes include protecting the wiring (circuit) patterns formed on the board by methods such as screen printing from the external environment, and the soldering process used when electronic components are surface-mounted on the printed wiring board. In order to prevent solder from adhering to unnecessary portions, a protective layer called a coverlay or solder resist is coated on the printed wiring board. Conventionally, epoxy-based carboxyl group-containing photosensitive resins are mainly used in curable resin compositions for solder resists used for such applications.

For example, in JP-A-10-282665, the carboxyl group of a resin having a radically polymerizable unsaturated acyl group and a carboxyl group, one epoxy group and one or more radically polymerizable unsaturated groups in one molecule. A solder photoresist ink composition using an ultraviolet curable resin obtained by reacting a combined compound has been proposed.
Japanese Patent No. 5556990 discloses that a saturated or unsaturated polybasic acid anhydride is added to a reaction product of a polyfunctional epoxy resin and an unsaturated monocarboxylic acid ester compound or a saturated or unsaturated polybasic acid ester compound. A photosensitive prepolymer obtained by further adding a compound having one glycidyl group and at least one ethylenically unsaturated group in one molecule after the reaction, and having at least one ethylenically unsaturated group in the molecule. A photosensitive resin composition containing a photopolymerizable monomer, a photopolymerization initiator, a blocked isocyanate and a bismaleimide compound has been proposed.

However, the cured film obtained from the resin composition using the carboxyl group-containing photosensitive resin as described above has good solder heat resistance, but has problems such as low bending property and large warpage. There was room for

An object of the present invention is to provide a curable resin composition that gives a cured product having not only solder heat resistance but also excellent bendability and low warpage, and a dry film, a cured product, and a printed wiring board using the same. That's what it is.

As a result of intensive research by the present inventors, a curable resin composition containing a specific carboxyl group-containing photosensitive resin contains at least two ethylenically unsaturated groups having 5 or more alkylene oxide skeletons. By blending the compound, the present inventors succeeded in obtaining a curable resin composition that gives a cured product having not only solder heat resistance but also excellent bendability and low warpage, thereby completing the present invention.

（式（１）中、Ｘは、炭素数７以上の脂環式骨格または芳香族骨格を表し、ｎは０以上の数を表す。）
［項６］
前記（Ｄ）成分として、一般式（１）中のＸがジシクロペンタジエン骨格であるエポキシ樹脂を含むことを特徴とする項５に記載の硬化性樹脂組成物。
［項７］
フレキシブルプリント配線板の製造に用いられることを特徴とする項１～６のいずれか１項に記載の硬化性樹脂組成物。
［項８］
項１～７のいずれか１項に記載の硬化性樹脂組成物から得られる樹脂層を有することを特徴とするドライフィルム。
［項９］
項１～７のいずれか１項に記載の硬化性樹脂組成物または項８に記載のドライフィルムの樹脂層を硬化して得られることを特徴とする硬化物。
［項１０］
項９に記載の硬化物を有することを特徴とするプリント配線板。 That is, the present invention is as follows.
[Section 1]
(A) a carboxyl group-containing resin;
(B) a photoinitiator;
(C) a resin composition containing an ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons,
As the component (A), epoxy resin (A1) is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. Including a carboxyl group-containing photosensitive resin obtained by adding a compound having a saturated group,
A curable resin composition comprising at least two ethylenically unsaturated group-containing compounds as the component (C).
[Section 2]
Item 2. The curable resin composition according to Item 1, wherein the component (C) has 5 to 30 alkylene oxide skeletons.
[Section 3]
Further, as the component (A), a carboxyl group-containing photosensitive resin obtained by reacting (A2) a bisphenol type epoxy resin with a carboxylic acid having an ethylenically unsaturated group and reacting the resulting hydroxyl group with an acid anhydride, and ( A3) The curable resin composition according to Item 1 or 2, which contains at least one of carboxyl group-containing resins having a urethane skeleton.
[Section 4]
Item 4. The curable resin composition according to any one of Items 1 to 3, wherein the content of component (A1) is 10 to 30 parts by weight with respect to 100 parts by weight of component (A).
[Section 5]
Item 5. The curable resin composition according to any one of items 1 to 4, further comprising (D) an epoxy resin having a structure represented by the following general formula (1).

(In formula (1), X represents an alicyclic skeleton or aromatic skeleton having 7 or more carbon atoms, and n represents a number of 0 or more.)
[Section 6]
Item 6. The curable resin composition according to item 5, wherein the component (D) contains an epoxy resin in which X in the general formula (1) is a dicyclopentadiene skeleton.
[Section 7]
Item 7. The curable resin composition according to any one of Items 1 to 6, which is used for manufacturing a flexible printed wiring board.
[Item 8]
Item 8. A dry film comprising a resin layer obtained from the curable resin composition according to any one of Items 1 to 7.
[Item 9]
A cured product obtained by curing the resin layer of the curable resin composition according to any one of Items 1 to 7 or the dry film according to Item 8.
[Item 10]
Item 10. A printed wiring board comprising the cured product according to item 9.

According to the present invention, there is provided a curable resin composition that gives a cured product having not only solder heat resistance but also excellent bendability and low warpage, and a dry film, a cured product, and a printed wiring board using the same. be able to.

The present invention is a resin composition comprising (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, and (C) an ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons. As the component (A), the epoxy resin (A1) is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. a carboxyl group-containing photosensitive resin (also simply referred to as component (A1)) to which a compound having a polyunsaturated group is added, and at least two ethylenically unsaturated group-containing compounds as the component (C). It is a curable resin composition characterized by

Each component of the curable resin composition of the present invention will be described below. (Meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions below.

(A) Carboxyl group-containing resin The composition of the present invention is reacted with a carboxylic acid having an ethylenically unsaturated group as (A) a carboxyl group-containing resin, (A1) an epoxy resin, and acid anhydride is added to the generated hydroxyl group. A carboxyl group-containing photosensitive resin obtained by adding a compound having a glycidyl group and an ethylenically unsaturated group to a carboxyl group-containing resin obtained by reacting a substance is included as an essential component.

As the carboxylic acid having an ethylenically unsaturated group, (meth)acrylic acid is preferably used.
Typical examples of the acid anhydride include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, endomethylene tetrahydro dibasic acid anhydrides such as phthalic acid, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, and methyltetrahydrophthalic anhydride; aromatics such as trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride Polyvalent carboxylic anhydrides; other polyvalent carboxylic anhydrides associated therewith such as, for example, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride dibasic acid anhydrides are preferred.

As the epoxy resin, any known epoxy resin having an epoxy group can be used. Examples include bifunctional epoxy resins having two epoxy groups in the molecule and polyfunctional epoxy resins having many epoxy groups in the molecule.
Examples of epoxy resins used as raw materials for component (A1) include bisphenol A type epoxy resins, brominated epoxy resins, novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, Hydantoin-type epoxy resin, alicyclic epoxy resin, trihydroxyphenylmethane-type epoxy resin, bixylenol-type or biphenol-type epoxy resin, or a mixture thereof; bisphenol S-type epoxy resin, bisphenol A novolak-type epoxy resin, tetraphenylolethane-type epoxy resin Epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidyl xylenoyl ethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, and the like. Among them, bisphenol type epoxy resins such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin and biphenol type epoxy resin are preferable.
Compounds having one glycidyl group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate and α-methylglycidyl (meth)acrylate, as the compound having a glycidyl group and an ethylenically unsaturated group. etc.

As a component (A1), the following resins (1) to (2) are further added with one glycidyl group and one or more (meth)acrylates in the molecule such as glycidyl (meth)acrylate and α-methylglycidyl (meth)acrylate ) A carboxyl group-containing photosensitive resin obtained by adding a compound having an acryloyl group is more preferable.

(1) A carboxyl group-containing photosensitive resin obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin having a functionality of two or more, and adding a dibasic acid anhydride to the hydroxyl group present in the side chain.
(2) A carboxyl group-containing photosensitizer obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a bifunctional epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the resulting hydroxyl groups. synthetic resin.

The composition of the present invention is reacted with (A) a carboxyl group-containing resin, and (A2) a bisphenol type epoxy resin is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. and (A3) a carboxyl group-containing resin having a urethane skeleton, from the viewpoint of solder heat resistance, bendability, and warpage resistance.
As the component (A2), a carboxyl group-containing photosensitive resin obtained by reacting a bisphenol type epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl group present in the side chain is more preferable.

Examples of (A3) a carboxyl group-containing resin having a urethane skeleton include the following resins (3) to (6).
(3) A carboxyl group-containing urethane resin produced by a polyaddition reaction between a diisocyanate and a carboxyl group-containing dialcohol compound.
(4) dialcohol compounds containing diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, and carboxyl groups such as dimethylolpropionic acid and dimethylolbutanoic acid; polycarbonate-based polyols; Carboxyl group-containing by polyaddition reaction of diol compounds such as polyether-based polyols, polyester-based polyols, polyolefin-based polyols, acrylic-based polyols, bisphenol A-based alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups Photosensitive urethane resin.
(5) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin obtained by a polyaddition reaction of a meth)acrylate or its partial acid anhydride-modified product and a carboxyl group-containing dialcohol compound.
(6) During the synthesis of the resin of (4) or (5) above, a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as hydroxyalkyl (meth)acrylate is added, and the terminal (Meth)acrylated carboxyl group-containing photosensitive urethane resin.
(7) One isocyanate group and one or more (meth)acryloyl groups in the molecule, such as equimolar reactants of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resins of (5) or (6) above A carboxyl group-containing photosensitive urethane resin terminally (meth)acrylated by adding a compound having
When the component (A2) is included, the flexibility of the cured product is improved and the bending property of the cured product is excellent, and when the component (A3) is included, the bending property and heat resistance of the cured product can be improved. .

In the carboxyl group-containing resin (A), the content of component (A1) is not particularly limited. However, if the content of the component (A1) is too low, the heat resistance improving effect of the component (A1) may be insufficient, and if it is too high, the bendability may be poor and warping may increase. From the viewpoint of the balance between heat resistance, bendability, and low warpage, the content of component (A1) is preferably 10 to 30 parts by weight, more preferably 10 to 30 parts by weight, per 100 parts by weight of component (A). 20 parts by weight.
(B) photoinitiator
In the present invention, the photopolymerization initiator used as the component (B) is not particularly limited as long as it is commonly used in curable resin compositions.

For example, benzophenone, N,N′-tetraalkyl-4,4′-diaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-1-[4 -(methylthio)phenyl]-2-morpholino-propanone-1 and other aromatic ketones, 4,4'-bis(dimethylamino)benzophenone (miheler ketone), 4,4'-bis(diethylamino)benzophenone, 4-methoxy- Aromatic ketones such as 4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(morpholinophenone)-butanone-1,2-ethylanthraquinone, phenanthrenequinone, benzoin methyl ether, benzoin ethyl ether, benzoinphenyl Benzoin ethers such as ethers, benzoins such as methylbenzoin and ethylbenzoin, benzyl derivatives such as benzyldimethylketal, 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4 ,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer 2,4,5-dimer such as 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer, etc. -Triarylimidazole dimer, 9-phenylacridine, acridine derivatives such as 1,7-bis(9,9'-acridinyl)heptane, N-phenylglycine, N-phenylglycine derivatives, coumarin compounds, etc. be done.
These can be used singly or in combination of two or more.

Component (B) includes an oxime ester photopolymerization initiator having an oxime ester group, an alkylphenone photopolymerization initiator, an α-aminoacetophenone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, and a titanocene photopolymerization initiator. One or more photopolymerization initiators selected from the group consisting of polymerization initiators can be suitably used.
Examples of the oxime ester-based photopolymerization initiator include commercially available products such as CGI-325, Irgacure OXE01 and Irgacure OXE02 manufactured by BASF Japan, N-1919 and NCI-831 manufactured by Adeka. A photopolymerization initiator having two oxime ester groups in the molecule can also be preferably used. As the oxime ester photopolymerization initiator, an oxime ester compound having a carbazole structure is preferred.
Commercially available alkylphenone-based photopolymerization initiators include α-hydroxyalkylphenone types such as Irgacure 184, Darocure 1173, Irgacure 2959 and Irgacure 127 manufactured by BASF Japan.
As the α-aminoacetophenone-based photopolymerization initiator, specifically, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N , N-dimethylaminoacetophenone, and the like. Commercially available products include Irgacure 907, Irgacure 369, and Irgacure 379 manufactured by BASF Japan.
Specific examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxy benzoyl)-2,4,4-trimethyl-pentylphosphine oxide and the like. Commercially available products include Lucirin TPO manufactured by BASF and Irgacure 819 manufactured by BASF Japan.
Titanocene-based photopolymerization initiators such as Irgacure 389 and Irgacure 784 manufactured by BASF Japan can also be suitably used as the photopolymerization initiator.
The amount of the photopolymerization initiator (B) is preferably 0.1 to 25 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the carboxyl group-containing resin (A). . By using 0.1 to 25 parts by mass, a cured film having excellent photocurability and resolution, improved adhesion and PCT resistance, and excellent chemical resistance such as electroless gold plating resistance can be obtained. be able to. In particular, when the content is 25 parts by mass or less, the effect of reducing outgassing can be obtained, and furthermore, the light absorption on the coating film surface becomes intense, and it is possible to suppress the deterioration of the deep-part curability.

(C) Ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons In the present invention, if component (C) has 5 or more alkylene oxide skeletons and contains an ethylenically unsaturated group , is not particularly limited. Compounds having 5 or more EO or PO in the molecule and 2 or more ethylenically unsaturated groups are preferred. Also, the component (C) preferably contains a structure having a (meth)acryloyl group at the terminal of the alkylene oxide skeleton. The number of ethylenically unsaturated groups is more preferably 2 or more and 4 or less, and most preferably 2 or more and 3 or less.
In addition, "EO" refers to "ethylene oxide", and "PO" refers to "propylene oxide". Further, hereinafter, “EO-modified” means having a block structure of ethylene oxide units (—CH ₂ —CH ₂ —O—), and “PO-modified” means having a block structure of propylene oxide units (—CH ₂ —CH ₂ It means having a block structure of —CH ₂ —O—, —CH(CH ₃ )—CH ₂ —O—, —CH ₂ —CH(CH ₃ )—O—).

（式中、ｌ＋ｍ＋ｎの合計が変性数を表し、ｌ＋ｍ＋ｎ≧５である。）

（式中、ｎが変性数を表し、ｎ≧５である。） As the component (C), a compound represented by the following general formula (1) or (2) is more preferable, for example, an EO-modified polyvalent acrylate.

(Wherein, the sum of l + m + n represents the degeneration number, and l + m + n ≥ 5.)

(Wherein, n represents the number of modifications, n≧5.)

"Having 5 or more alkylene oxide skeletons" means having 5 or more alkylene oxide skeletons of all kinds in total when two or more kinds of alkylene oxide skeletons are contained. If the number is less than 5, the excellent bendability and low warpage of the present invention cannot be achieved.
From the viewpoint of balance with other performances, the component (C) preferably has 5 to 30 alkylene oxide skeletons, more preferably 5 to 20 alkylene oxide skeletons. When the number of alkylene oxide skeletons is 30 or less, the thickness of the cured film can be easily secured without adjusting the viscosity of the composition.
In the present invention, at least two ethylenically unsaturated group-containing compounds must be included as component (C). If the component (C) is only one ethylenically unsaturated group-containing compound, the cured product of the present invention cannot be warped, and the bendability and soldering heat resistance may be lowered.

The total amount of component (C) is preferably 1 to 40 parts by mass, more preferably 10 to 35 parts by mass, more preferably 15 to 30 parts by mass, relative to 100 parts by mass of the carboxyl group-containing resin (A). Parts by mass are more preferred.

（式（１）中、Ｘは、炭素数７以上の脂環式骨格または芳香族骨格を表し、ｎは０以上の数を表す。）
前記一般式（１）中のＸがジシクロペンタジエン骨格であることが、本発明の効果を著しく発揮するので好ましい。
なお、本発明においては、（Ｄ）成分以外のエポキシ樹脂、例えば上記のビスフェノールＡ型エポキシ樹脂等を含んでいてもよい。 Other Components In addition to the above components (A) to (C), the present invention may further contain (D) an epoxy resin having the structure of the following general formula (1).

(In formula (1), X represents an alicyclic skeleton or aromatic skeleton having 7 or more carbon atoms, and n represents a number of 0 or more.)
It is preferable that X in the general formula (1) is a dicyclopentadiene skeleton because the effects of the present invention are exhibited remarkably.
In addition, in the present invention, an epoxy resin other than the component (D), such as the bisphenol A type epoxy resin described above, may be included.

In the present invention, in addition to the above components (A) to (C), (E) a diamine having an ether skeleton may also be included. Examples of component (E) include JEFFAMINE D-230 and JEFFAMINE D-2000 (manufactured by Huntsman).
From the viewpoint of the developability and pot life of the curable resin composition of the present invention, the component (E) preferably contains a polyetheramine (also referred to as polyetherdiamine) having 15 or more ether skeletons, and more From the viewpoint of pot life and heat resistance, it is preferable to include both a diamine having 1 to 10 ether skeletons and a polyetheramine having 20 to 40 ether skeletons. The content of the diamine having 1 to 10 ether skeletons is preferably 1 to 40 parts by weight per 100 parts by weight of the total weight of the component (E), and the poly The ether amine content is preferably 60 to 99 parts by weight per 100 parts by weight of the total weight of component (E).

In addition, the curable resin composition of the present invention contains (F) a trifunctional or higher ethylenically unsaturated group-containing compound (excluding component (C)) for improving the crosslink density, as long as it does not interfere with the effects of the present invention. may contain. Examples of the component (F) include trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO/PO-modified trimethylolpropane tri(meth)acrylate, ) acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate and the like.
Furthermore, the curable resin composition of the present invention may contain known and commonly used materials such as barium sulfate, silicon oxide, talc, clay, calcium carbonate, silica, bentonite, kaolin, glass fiber, carbon fiber, and mica, depending on the desired physical properties. fillers, known and commonly used dyes and coloring pigments such as phthalocyanine blue, phthalocyanine green, titanium oxide, carbon black, various additives such as antifoaming agents, flame retardants, adhesion imparting agents or leveling agents, or hydroquinone, hydroquinone Known and commonly used polymerization inhibitors such as monomethyl ether, pyrogallol, t-butylcatechol and phenothiazine may be added.
Furthermore, the curable resin composition of the present invention may contain an organic solvent used for preparing the composition and adjusting the viscosity. Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol; Glycol ethers such as monomethyl ether, dipropylene glycol monomethyl ether (DPM), dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbi Esters such as tall acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. can do. These organic solvents can be used alone or in combination of two or more.
According to the curable resin composition of the present invention, a cured product having not only solder heat resistance but also excellent bending property and low warpage property can be obtained, so that it is preferably used for the production of flexible printed wiring boards.

Another aspect of the present invention provides a dry film having a resin layer obtained from the above curable resin composition.
The dry film of the present invention can be obtained by coating on a carrier film (support) and drying. When forming a dry film, the composition of the present invention is diluted with the above organic solvent as necessary to adjust the viscosity to an appropriate value, and is coated with a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, It is coated on a carrier film with a uniform thickness using a transfer roll coater, gravure coater, spray coater, etc., and usually dried at a temperature of 50 to 130° C. for 1 to 30 minutes to form a resin layer as a dry coating film. can be done. Although the thickness of the resin layer is not particularly limited, it is generally selected appropriately within the range of 0.1 to 100 μm, preferably 0.5 to 50 μm, in terms of film thickness after drying.

As the carrier film, a plastic film is used, and it is preferable to use a plastic film such as a polyester film such as polyethylene terephthalate, a polyimide film, a polyamideimide film, a polypropylene film and a polystyrene film. The thickness of the carrier film is not particularly limited, but is generally selected appropriately within the range of 0.1 to 150 μm.
In this case, after forming the resin layer on the carrier film, it is preferable to further laminate a peelable cover film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, or the like can be used. is smaller than the adhesive force between the resin layer and the carrier film.

Another form of the present invention provides a cured product obtained from the above curable resin composition.
The curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method as necessary, and is applied to a printed wiring board having a circuit formed thereon by, for example, a screen printing method, a curtain coating method, a spray coating method, or a roll coating method. A tack-free coating film can be formed by applying the composition according to a method such as a method of the present invention, and optionally drying the organic solvent contained in the composition at a temperature of 60 to 100° C., for example. After that, the obtained coating film or the resin layer of the dry film is selectively exposed by irradiation with active energy rays through a photomask having a predetermined exposure pattern, and the unexposed area is developed with a developer to form a resist pattern. Further, for example, by heating to a temperature of 140 to 180° C. for thermal curing, a cured product excellent in soldering heat resistance, bending property and low warpage property can be obtained as a resist film.

The volatilization drying performed after applying the composition of the present invention is performed using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, or the like, which is equipped with a steam air heating type heat source, and directs the hot air in the dryer. It can be carried out using a method of flowing contact and a method of spraying the support from a nozzle.

The exposure device used for active energy ray irradiation may be any device equipped with a high-pressure mercury lamp, an extra-high pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and irradiating ultraviolet rays in the range of 350 to 450 nm. A direct drawing device (for example, a direct imaging device that draws an image by directly irradiating active energy rays according to CAD data from a computer) can also be used. As the light source of the direct drawing machine, any light having a maximum wavelength in the range of 350 to 410 nm may be used. The amount of exposure for image formation varies depending on the film thickness and the like, but can generally be in the range of 20-1000 mJ/cm ² , preferably in the range of 20-800 mJ/cm ² .
Examples of the developing method include a dipping method, a shower method, a spray method, and a brush method. Examples of the developing solution include potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate Dilute alkaline aqueous solutions such as ammonia and amines can be used.

Moreover, this invention provides the printed wiring board which has said hardened|cured material.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but it goes without saying that the present invention is not limited to the following examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

A curable resin composition was obtained by mixing each component shown in Table 1 at the solid content mixing ratio (mass basis) shown therein.
[(A1) Component Synthesis Example 1]
To 700 g of diethylene glycol monoethyl ether acetate, add 1070 g of ortho-cresol novolac type epoxy resin (manufactured by DIC, EPICLON N-695, softening point 95° C., epoxy equivalent weight 214, average functional group number 7.6) (number of glycidyl groups (total number of aromatic rings) ): 5.0 mol), 360 g (5.0 mol) of acrylic acid, and 1.5 g of hydroquinone were charged, heated to 100° C. with stirring, and uniformly dissolved.
Then, 4.3 g of triphenylphosphine was charged, heated to 110° C. and reacted for 2 hours, then 1.6 g of triphenylphosphine was added, the temperature was raised to 120° C. and the reaction was further carried out for 12 hours. 562 g of aromatic hydrocarbon (Solvesso 150) and 684 g (4.5 mol) of tetrahydrophthalic anhydride were added to the obtained reaction liquid, and the reaction was carried out at 110° C. for 4 hours. Further, 142.0 g (1.0 mol) of glycidyl methacrylate was added to the resulting reaction solution and reacted at 115° C. for 4 hours to obtain a carboxyl group-containing photosensitive resin solution as component (A1). The resin solution thus obtained had a solid content of 65% and an acid value of the solid content of 87 mgKOH/g.

[Synthesis example of component (A2)]
925 parts of epichlorohydrin and 462.5 parts of dimethyl sulfoxide are dissolved in 400 parts of bisphenol F solid epoxy resin having an epoxy equivalent of 800 and a softening point of 79°C, and then 81.2 parts of 98.5% NaOH is added to 100 parts at 70°C while stirring. added in portions. After the addition, the reaction was further carried out at 70°C for 3 hours.
Next, most of the excess unreacted epichlorohydrin and dimethyl sulfoxide were distilled off under reduced pressure, the reaction product containing the by-product salt and dimethyl sulfoxide was dissolved in 750 parts of methyl isobutyl ketone, and 10 parts of 30% NaOH was further added and the temperature was kept at 70°C. was reacted for 1 hour. After completion of the reaction, it was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was recovered from the oil layer by distillation to obtain 370 parts of epoxy resin (a-1) having an epoxy equivalent of 290 and a softening point of 62°C.
Epoxy resin (a-1) obtained 2900 parts (10 equivalents (10 mol with epoxy group)), 720 parts of acrylic acid (10 equivalents (10 mol with carboxyl group)), 2.8 parts of methyl hydroquinone, carbitol acetate 1950 parts were charged, heated to 90° C. and stirred to dissolve the reaction mixture. Then, the reaction solution was cooled to 60°C, charged with 16.7 parts of triphenylphosphine, heated to 100°C, and reacted for about 32 hours to obtain a reactant having an acid value of 1.0 mgKOH/g. Next, 786 parts of maleic anhydride (7.86 mol in terms of acid anhydride structure) and 423 parts of carbitol acetate were added thereto, heated to 95° C., and reacted for about 6 hours to obtain a photosensitive carboxyl group-containing resin. A solution was obtained.
The solid content of the resin solution thus obtained was 65%, and the acid value of the solid content was 100 mgKOH/g.

[Synthesis example of component (A3)]
A polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (T5650J manufactured by Asahi Kasei Chemicals Co., Ltd.) was placed in a reaction vessel equipped with a stirrer, a thermometer, and a condenser as a compound having multiple alcoholic hydroxyl groups. , 3600 g (4.5 mol) of number average molecular weight 800), 814 g (5.5 mol) of dimethylolbutanoic acid, and 118 g (1.6 mol) of n-butanol as a molecular weight modifier (reaction terminator). bottom. Next, 2009 g (10.8 mol) of trimethylhexamethylene diisocyanate was added as an isocyanate compound having no aromatic ring, heated to 60° C. with stirring, and stopped. The mixture was heated again and stirred at 80° C. After confirming that the absorption spectrum (2280 cm −1 ) of the isocyanate group disappeared in the infrared absorption spectrum, the reaction was terminated. Then, carbitol acetate was added so that the solid content was 60 wt % to obtain a viscous liquid carboxyl group-containing resin containing a diluent. The acid value of the solid content of the carboxyl group-containing resin having a urethane skeleton (A3) was 49.8 mgKOH/g.

As commercially available materials, BASF Japan Irgacure 784, Irgacure 369, 4,4'-bis (diethylamino) benzophenone (EAB) is used as a photopolymerization initiator, and as a dicyclopentadiene type solid epoxy, Nippon Kayaku Using XD-1000 manufactured by Co., Ltd., using NC-3000 manufactured by Nippon Kayaku Co., Ltd. as biphenyl novolak type epoxy, and using A-600 and A-400 manufactured by Shin-Nakamura Chemical Co., Ltd. as EO-modified acrylic monomers. , A-GLY-20E was used. In addition, DPHA (dipentaerythritol triacrylate, manufactured by Nippon Kayaku Co., Ltd.), JEFFAMINE D-230, JEFFAMINE D-2000 (manufactured by Huntsman).

Each composition of Examples 1 to 8 and Comparative Examples 1 to 3 was screen-printed on a polyimide substrate having a copper circuit (thickness of polyimide film: 25 μm, copper circuit: 1/3 oz) to a thickness of 10 μm after drying. and dried at 160 ° C. for 30 minutes in a hot air circulation drying oven to form a dry coating film, then exposed with an exposure amount that gives a sensitivity of 7 steps with an exposure machine equipped with a metal halide lamp manufactured by Oak Manufacturing Co., Ltd. bottom. After that, it was developed with a 1 wt% Na ₂ CO ₃ aqueous solution at a spray pressure of 0.1 MPa for 1 minute, and then heat-cured at 150°C for 60 minutes using a hot air circulating drying oven to obtain a thickness of 10 µm on the polyimide substrate. A cured coating film was produced.

Table 1 shows the evaluation results of the cured coating films of the obtained curable resin compositions. The evaluation method and evaluation criteria are as follows.
(Cured product-Low warpage evaluation)
A polyimide substrate having a cured coating film was cut into a size of 5 cm×5 cm to prepare an evaluation sample. With the surface of the cured coating film facing upward, the warpage at each corner was measured with a ruler, and the average value of the four points was evaluated.
○: Average value of each corner warp 2 mm or less △: Average value of each corner warp 3 mm or less ×: Average value of each corner warp 4 mm or less (bending property)
A polyimide substrate having a cured coating film was cut into a size of 10 mm in width×70 mm in length to prepare an evaluation sample. The surface of the cured coating film was folded into a mountain, and a weight of 1 kg was placed on it. Then, the weight was again put on the bent portion for 10 seconds, which was regarded as one time. The bent portion was observed with a microscope, and the number of times until the copper was visible was evaluated.
○: Number of times of bending -2 times △: Number of times of bending -1 time ×: Number of times of bending -0 times (solder heat resistance test)
A polyimide substrate having a cured coating film was cut into a size of 20 mm long×20 mm wide to prepare an evaluation sample. The temperature of the solder bath was set to 320° C., and the sample substrate was placed in the bath. After 10 seconds, the substrate was taken out, and swelling of the cured coating film on the substrate surface was confirmed, and the number of times until swelling appeared was evaluated.
○: 320°C x 10 seconds 3 times or more △: 320°C x 10 seconds twice x: 320°C x 10 seconds once

As is clear from Table 1, any of Examples 1 to 8 in which the component (A1) was used and two ethylenically unsaturated group-containing compounds having 5 or more alkylene oxide skeletons were used in combination, the cured product Excellent results were obtained in the evaluation of low warpage, bendability, and solder heat resistance. On the other hand, Comparative Examples 1 and 2 using only one ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons, and Comparative Example 3 containing no component (A1) have insufficient performance. rice field. Specifically, in Comparative Example 1, all of the low warpage property, bendability, and solder heat resistance of the cured product were slightly poor. In Comparative Example 2, the low warpage property of the cured product was slightly poor. In Comparative Example 3, the cured product was slightly inferior in low warpage property and bending property, and poor in solder heat resistance.
From these results, it was found that the curable resin composition of the present invention can form a cured product that is excellent not only in soldering heat resistance but also in bendability and low warpage. Due to its excellent bendability and low warpage, it is also suitable for use in flexible printed wiring boards.

Claims (9)

(A) a carboxyl group-containing resin;
(B) a photoinitiator;
(C) a resin composition containing an ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons,
As the component (A), epoxy resin (A1) is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. Including a carboxyl group-containing photosensitive resin obtained by adding a compound having a saturated group,
At least two ethylenically unsaturated group-containing compounds are included as the component (C),
Further, as the component (A), a carboxyl group-containing photosensitive resin obtained by reacting (A2) a bisphenol type epoxy resin with a carboxylic acid having an ethylenically unsaturated group and reacting the resulting hydroxyl group with an acid anhydride, and ( A3) A curable resin composition comprising at least one carboxyl group-containing resin having a urethane skeleton. (A) a carboxyl group-containing resin;
(B) a photoinitiator;
(C) a resin composition containing an ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons,
As the component (A), epoxy resin (A1) is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. Including a carboxyl group-containing photosensitive resin obtained by adding a compound having a saturated group,
At least two ethylenically unsaturated group-containing compounds are included as the component (C),
A curable resin composition characterized in that the content of component (A1) is 10 to 30 parts by weight per 100 parts by weight of component (A). (A) a carboxyl group-containing resin;
(B) a photoinitiator;
(C) a resin composition containing an ethylenically unsaturated group-containing compound having 5 or more alkylene oxide skeletons,
As the component (A), epoxy resin (A1) is reacted with a carboxylic acid having an ethylenically unsaturated group, and the resulting hydroxyl group is reacted with an acid anhydride. Including a carboxyl group-containing photosensitive resin obtained by adding a compound having a saturated group,
At least two ethylenically unsaturated group-containing compounds are included as the component (C),
A curable resin composition further comprising (D) an epoxy resin having a structure represented by the following general formula (1).

(In formula (1), X represents an alicyclic skeleton or aromatic skeleton having 7 or more carbon atoms, and n represents a number of 0 or more.) 4. The curable resin composition according to any one of claims 1 to 3, wherein the component (C) has 5 to 30 alkylene oxide skeletons. 4. The curable resin composition according to claim 3, wherein the component (D) contains an epoxy resin in which X in the general formula (1) is a dicyclopentadiene skeleton. 6. The curable resin composition according to any one of claims 1 to 5, which is used for manufacturing a flexible printed wiring board. A dry film comprising a resin layer obtained from the curable resin composition according to any one of claims 1 to 6. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 6 or the resin layer of the dry film according to claim 7. A printed wiring board comprising the cured product according to claim 8 .