JP6388450B2 - Alkali development type photocurable thermosetting resin composition and printed wiring board using the same - Google Patents

Description

  The present invention relates to an alkali-developable photocurable thermosetting resin composition and a flexible printed wiring board, and in particular, it can be developed with alkali, has excellent flexibility, and is free from sagging during heat treatment after development. In particular, an alkali-developable photocurable thermosetting resin composition having good deep-part curability and excellent pattern formability and a cured product of the alkali-developable photocurable thermosetting resin composition The present invention relates to a flexible printed wiring board provided.

  In recent years, the spread of smartphones and tablet terminals and the improvement of performance are progressing rapidly. Information equipment terminals represented by these are highly demanded by consumers for downsizing and thinning, and in order to meet these demands, it is necessary to increase the density of circuit boards inside the products and save space. Therefore, the use of flexible printed wiring boards that can be folded and stored and that can increase the degree of freedom of circuit arrangement is expanding, and the reliability for flexible printed wiring boards is required to be higher than ever. Yes.

  Currently, a polyimide-based coverlay is used for the bent part (bent part) as an insulating film to ensure the insulation reliability of the flexible printed wiring board, and the mounting part (non-bent part) is photosensitive. A mixed loading process using a conductive resin composition is widely employed (see Patent Documents 1 and 2). Polyimide is excellent in mechanical properties such as heat resistance and flexibility, while the photosensitive resin composition used in the mounting part has characteristics such as excellent electrical insulation and solder heat resistance and can be finely processed. .

  Conventional polyimide-based coverlays are not suitable for fine wiring because they require processing by die punching. For this reason, an alkali-developable photosensitive resin composition (solder resist) that can be processed by photolithography is partially used together in a chip mounting portion that requires fine wiring. When partially using such a resin composition in the production of a flexible printed wiring board, two processes, a process of bonding a cover lay and a process of forming a solder resist, are performed, resulting in cost and workability. There was a problem of being inferior.

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

  So far, coverlays that do not depend on the mixed loading process have been studied. For example, application of a photosensitive resin composition for a solder resist as a coverlay for a flexible printed wiring board has been studied. However, in a resin composition for a solder resist, impact resistance, flexibility, etc. as a coverlay The reliability is insufficient. Since the resin composition for solder resist is accompanied by curing shrinkage due to acrylic photopolymerization, there is a problem in dimensional stability such as warping of a flexible wiring board.

  Accordingly, an object of the present invention is an alkali development type photocuring which is excellent in flexibility and workability, and suitable for a batch forming process of an insulating film of a flexible printed wiring board, particularly a bent portion (bent portion) and a mounting portion (non-bent portion). It is providing a heat-resistant thermosetting resin composition.

As a result of intensive studies to solve the above problems, the present inventors have found that a resin composition containing a urethane resin having a carboxyl group, a photobase generator, and a thermosetting component can solve the above problems.
That is, the photobase generator is activated by light irradiation, and the urethane resin having a carboxyl group and the thermosetting component are subjected to an addition reaction by heating using the generated base as a catalyst, whereby only the unexposed portion is removed with an alkaline solution. It has been found that this is possible. As a result, fine processing by alkali development is possible, and since a urethane resin is included, it can be expected to obtain a cured product having excellent flexibility.

However, when a composition containing a urethane resin having a carboxyl group, a thermosetting component and a photobase generator is heat-cured subsequent to development after light irradiation, the resin melts by heating, and so-called sagging occurs. It was recognized that the pattern may collapse.
Therefore, the present inventors have further studied and found that the above problems can be solved by containing a resin having a carboxyl group other than the urethane resin in addition to the above components, and have completed the present invention. Further, blending a monomer having an ethylenically unsaturated group into the composition, or using a urethane resin having a carboxyl group as the urethane resin having an ethylenically unsaturated group can further prevent the occurrence of sagging. It was also found that it is preferable because it can be expected.

  On the other hand, it has been clarified that there is room for improvement in deep curability when fine processing by alkali development is performed using an addition reaction using a base generated by light irradiation as a catalyst as described above. In particular, when the alkali-developable resin composition is used for a layer close to the substrate in the multilayer coverlay, light is absorbed by the resin or photosensitizer contained in the upper layer, and the light does not reach the depth of the resin layer sufficiently. There was a thing.

  Therefore, the present inventors have further studied and found that the above problem can be solved by adopting an oxime ester photobase generator having a specific structure as a photobase generator. In addition, in the heat curing reaction after light irradiation of the alkali development type photocurable thermosetting resin composition, the selection range of the heating temperature and the heating time can be widened, and the resin composition is more excellent in workability. It was also found.

（式中、Ｒ^１は、水素原子、無置換または炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されたフェニル基、無置換または１個以上の水酸基で置換された炭素数１〜２０のアルキル基、１個以上の酸素原子で中断された該アルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数５〜８のシクロアルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数２〜２０のアルカノイル基又はベンゾイル基を表し、
Ｒ^２は、無置換または炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されたフェニル基、無置換または１個以上の水酸基で置換された炭素数１〜２０のアルキル基、１個以上の酸素原子で中断された該アルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数５〜８のシクロアルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数２〜２０のアルカノイル基又はベンゾイル基を表す。）
［３］前記カルボキシル基を有するウレタン樹脂がエチレン性不飽和基を有するものである［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物。
［４］さらに、エチレン性不飽和基を有するモノマーを含む［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物。
［５］前記熱硬化成分が環状エーテル化合物である［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物。
［６］カバーレイ接着層用である［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物。
［７］［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物を塗布、乾燥させてなる樹脂層を有することを特徴とするドライフィルム。
［８］［１］のアルカリ現像型光硬化性熱硬化性樹脂組成物、または、［７］のドライフィルムを硬化してなることを特徴とする硬化物。
［９］［８］の硬化物を備えることを特徴とするフレキシブルプリント配線板。The present invention includes the following [1] to [9].
[1] An alkali developing photocurable thermosetting resin composition comprising a urethane resin having a carboxyl group, a resin having a carboxyl group other than the urethane resin, a photobase generator, and a thermosetting component. .
[2] The alkali development type photocurable thermosetting resin composition according to [1], wherein the photobase generator includes an oxime ester photobase generator having a group represented by the following general formula (I).

(Wherein R ¹ is a hydrogen atom, an unsubstituted or alkyl group having 1 to 6 carbon atoms, a phenyl group substituted with a phenyl group or a halogen atom, unsubstituted or substituted with one or more hydroxyl groups. -20 alkyl group, the alkyl group interrupted by one or more oxygen atoms, unsubstituted, C1-C6 alkyl group or phenyl group substituted with C5-C8 cycloalkyl group, unsubstituted Or an alkanoyl group having 2 to 20 carbon atoms or a benzoyl group substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group,
R ² represents an unsubstituted or alkyl group having 1 to 6 carbon atoms, a phenyl group substituted with a phenyl group or a halogen atom, an unsubstituted or alkyl group having 1 to 20 carbon atoms substituted with one or more hydroxyl groups, The alkyl group interrupted by one or more oxygen atoms, unsubstituted or a cycloalkyl group having 5 to 8 carbon atoms substituted by an alkyl group having 1 to 6 carbon atoms or a phenyl group, unsubstituted or having 1 to 6 carbon atoms An alkanoyl group having 2 to 20 carbon atoms or a benzoyl group substituted with an alkyl group or a phenyl group is represented. )
[3] The alkali development type photocurable thermosetting resin composition of [1], wherein the urethane resin having a carboxyl group has an ethylenically unsaturated group.
[4] The alkali development type photocurable thermosetting resin composition according to [1], further comprising a monomer having an ethylenically unsaturated group.
[5] The alkali development type photocurable thermosetting resin composition of [1], wherein the thermosetting component is a cyclic ether compound.
[6] The alkali development type photocurable thermosetting resin composition according to [1], which is used for a coverlay adhesive layer.
[7] A dry film comprising a resin layer formed by applying and drying the alkali development type photocurable thermosetting resin composition of [1].
[8] A cured product obtained by curing the alkali development type photocurable thermosetting resin composition of [1] or the dry film of [7].
[9] A flexible printed wiring board comprising the cured product of [8].

According to the present invention, it is possible to provide an alkali development type photocurable thermosetting resin composition in which the occurrence of sagging during heat curing after development is suppressed. Also, an alkali development type photo-curable thermosetting resin composition that is excellent in flexibility and suitable for a batch forming process of an insulating film of a flexible printed wiring board, particularly a bent portion (bent portion) and a mounting portion (non-bent portion), And it becomes possible to provide a printed wiring board provided with the hardened | cured material. Moreover, the alkali development type photocurable thermosetting resin composition of the present invention is easy to manage temperature and time at the time of heat curing after light irradiation, and is excellent in workability.
The alkali development type photocurable thermosetting resin composition of the present invention is suitable for a coverlay of a flexible printed wiring board. The alkali-developable photocurable thermosetting resin composition of the present invention is also suitable as a resin composition for an adhesive layer of a multilayer coverlay. Here, the adhesive layer refers to a resin layer in contact with the flexible printed board of a cover lay having a laminated structure of two or more layers.

  Further, by using an oxime ester photobase generator having a group represented by the above general formula (I) as a photobase generator, an alkali development type photocurable thermosetting resin composition excellent in deep part curability Things can be provided. Furthermore, the selection range of the temperature and time at the time of heat curing after light irradiation is widened, and the workability is excellent.

It is process drawing which shows typically an example of the manufacturing method of the flexible printed wiring board of this invention.

The alkali development type photocurable thermosetting resin composition of the present invention (hereinafter also simply referred to as “the resin composition of the present invention”) is a urethane resin having a carboxyl group, a resin having a carboxyl group other than a urethane resin, It contains a photobase generator and a thermosetting component.
The resin composition of the present invention is prepared by subjecting a urethane resin having a carboxyl group and a thermosetting component to an addition reaction by heating after exposure using a base generated from a photobase generator as a catalyst, and removing an unexposed portion with an alkaline solution. Is a resin composition that can be developed.
A resin composition containing a carboxyl group-containing urethane resin, a thermosetting component, and a photobase generator is further blended with a resin other than the urethane resin and having a carboxyl group, so that dripping at the time of heat curing after development can be achieved. Can be suppressed. Although the detailed mechanism is not clear, one possible reason is that the carboxyl group in the urethane resin having a carboxyl group has low reactivity with the thermosetting component and has a carboxyl group in a resin other than the urethane resin By blending, the addition reaction at the time of heat curing after development further proceeds, and a strong matrix can be formed.

  In addition, the resin composition of the present invention preferably contains an ethylenically unsaturated group in the system from the viewpoint of the effect of suppressing the occurrence of sagging. The ethylenically unsaturated group may be present in the urethane resin having a carboxyl group, and a monomer having an ethylenically unsaturated group to be described later may be further added to the resin composition of the present invention. Or both. It is considered that the presence of the ethylenically unsaturated group causes a radical polymerization reaction by light to form a strong matrix and suppress the occurrence of sagging during heat curing after development.

The resin composition of the present invention is suitable for a resin insulating layer of a flexible printed wiring board, for example, a coverlay or a solder resist.
When forming the resin insulation layer of a flexible printed wiring board using the resin composition of this invention, a suitable manufacturing method is as follows. That is, a step of forming a resin layer made of the resin composition of the present invention on a flexible printed wiring board, a step of irradiating the resin layer with light in a pattern, and a step of heating the resin layer (also referred to as Post Exposure Bake; PEB) And a method of forming the resin insulating layer having a pattern by alkali-developing the resin layer. If necessary, after alkali development, further light irradiation or heat curing (post-cure) is performed to completely cure the resin composition to obtain a highly reliable resin insulating layer.
As described above, the resin composition of the present invention is preferably capable of forming a negative pattern by alkali development by an addition reaction between a carboxyl group and a thermosetting component by heat treatment after selective light irradiation. It is possible.
Since the resulting cured product is excellent in heat resistance and flexibility and can be finely processed by alkali development, there is no need to partially use an alkali-developable photosensitive resin composition, and a flexible printed wiring board It can be used for both the bent part (bent part) and the mounting part (non-bent part), and is suitable for the batch formation process of the bent part (bent part) and the mounting part (non-bent part).

As described above, the carboxyl group in the urethane resin has low reactivity, and compared with the case where only other carboxyl group-containing resin is included, the heat curing reaction after exposure (during the PEB process) is performed under the same heating temperature. It is possible to lengthen the time until alkali resistance is achieved by the addition reaction. Moreover, the selection range of the heating temperature at the time of thermosetting reaction (at the time of PEB process) can be expanded. From these things, the workability | operativity and handleability of a resin composition improve. It is also possible to suppress the occurrence of so-called fogging in which the unexposed portion becomes resistant to alkali.
Hereinafter, each component will be described in detail.

[Urethane resin having carboxyl group]
As the urethane resin having a carboxyl group contained in the resin composition of the present invention, a known and commonly used urethane resin compound containing a carboxyl group in the molecule can be used. Further, as described above, a carboxyl group-containing urethane resin having an ethylenically unsaturated double bond in the molecule is preferable from the viewpoint of improving the effect of preventing the occurrence of sagging during heating. Here, sagging refers to a phenomenon in which, when the resin composition is heat-cured subsequent to development after light irradiation, the resin melts by heating and the pattern collapses. As the ethylenically unsaturated double bond, those derived from (meth) acrylic acid or (meth) acrylic acid derivatives are preferable. Specific examples of the urethane resin having a carboxyl group include the compounds listed below as (1) to (4) (any of oligomers and polymers).

(1) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates; carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.
(2) 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 ( Photosensitive carboxyl group-containing urethane resin by polyaddition reaction of (meth) acrylate or its modified partial anhydride, carboxyl group-containing dialcohol compound and diol compound.
(3) During the synthesis of the resin of the above (1) or (2), a compound having one hydroxyl group and one or more (meth) acryl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( Photosensitive carboxyl group-containing urethane resin that has been meta-acrylated.
(4) During the synthesis of the resin of the above (1) or (2), one isocyanate group and one or more (meth) acryl groups are introduced into the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. The photosensitive carboxyl group-containing urethane resin which added the compound which has and was terminally (meth) acrylated.
The urethane resin having a carboxyl group preferably has an acid value of 20 to 200 mgKOH / g, and more preferably 40 to 150 mgKOH / g. When the acid value is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.
The mass average molecular weight of the urethane resin having a carboxyl group is preferably 1,000 to 100,000, and more preferably 3,000 to 50,000. By setting the mass average molecular weight to 1,000 or more, sufficient flexibility of the cured product can be obtained. Further, when the mass average molecular weight is 100,000 or less, the alkali developability can be improved.
The compounding amount of the urethane resin having a carboxyl group is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, in a total of 100 parts by mass of the urethane resin having a carboxyl group and the resin having a carboxyl group other than the urethane resin. preferable. Flexibility becomes favorable by mix | blending 10 mass parts or more.

[Resin having a carboxyl group other than urethane resin]
The resin having a carboxyl group other than the urethane resin contained in the resin composition of the present invention is a resin other than the above urethane resin having a carboxyl group, and is a resin having a carboxyl group in the molecule. As such a resin, a known and commonly used resin compound containing a carboxyl group in the molecule can be used. Further, it may be a resin having an ethylenically unsaturated double bond in the molecule. As the ethylenically unsaturated double bond, those derived from (meth) acrylic acid or (meth) acrylic acid derivatives are preferable.
Specific examples of resins other than urethane having a carboxyl group include compounds (any of oligomers and polymers) listed below as (5) to (11).

(5) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.
(6) A photosensitive carboxyl group-containing resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.
(7) Photosensitivity in which (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Functional carboxyl group-containing resin.
(8) A carboxyl group-containing polyester resin obtained by reacting a difunctional oxetane resin with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group.
(9) Unsaturated reaction products obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing photosensitive resin obtained by partial esterification with a group-containing monocarboxylic acid and reacting the resulting reaction product with a polybasic acid anhydride.
(10) A polybasic reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and / or a cyclic carbonate compound such as ethylene carbonate or propylene carbonate. A carboxyl group-containing resin obtained by reacting an acid anhydride.
(11) A photosensitive carboxyl group-containing resin obtained by adding a compound having one epoxy group and one or more (meth) acryl groups in one molecule to the resins (5) to (10).
The resin having a carboxyl group other than the urethane resin preferably has an acid value of 20 to 200 mgKOH / g, and more preferably 40 to 150 mgKOH / g. When the acid value is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.
Moreover, 1,000-100,000 are preferable and, as for the mass mean molecular weight of resin which has carboxyl groups other than urethane resin, 3,000-50,000 are preferable. When the molecular weight is within the above range, the alkali solubility is good and patterning by alkali development becomes easy.
The blending amount of the resin having a carboxyl group other than the urethane resin is 5 parts by mass or more, preferably 20 parts by mass or more, in a total of 100 parts by mass of the urethane resin having a carboxyl group and the resin having a carboxyl group other than the urethane resin. Is preferred. By blending 5 parts by mass or more, the development resistance of the exposed part can be obtained at a low temperature or in a short time during heating after light irradiation (PEB process).

[Photobase generator]
The photobase generator used in the present invention is used as a catalyst for the addition reaction of a carboxyl group and a thermosetting component described later when the molecular structure is changed by irradiation with light such as ultraviolet rays or visible light, or when the molecule is cleaved. It is a compound that produces one or more basic substances that can function. Examples of basic substances include secondary amines and tertiary amines.
When the resin composition of the present invention has an ethylenically unsaturated group in the system, it is possible to initiate a polymerization reaction of the ethylenically unsaturated group by light irradiation. Those that also function as a photo-radical polymerization initiator that generates radicals in the above process are preferred.
Examples of photobase generators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, nitrobenzyl carbamate groups, and alkoxyoxybenzyl carbamates. And compounds having a substituent such as a group. Of these, oxime ester compounds and α-aminoacetophenone compounds are preferred. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

  Other photobase generators include WPBG-018 (trade name: 9-anthrylmethylN, N'-diethylcarbamate), WPBG-027 (trade name: (E) -1- [3- (2-hydroxyphenyl) -2-propenoyl ] piperidine), WPBG-082 (trade name: guanidinium2- (3-benzoylphenyl) propionate), WPBG-140 (trade name: 1- (anthraquinon-2-yl) ethyl imidazolecarboxylate), and the like can also be used.

  The α-aminoacetophenone compound has a benzoin ether bond in the molecule, and when irradiated with light, cleavage occurs in the molecule to produce a basic substance (amine) that exhibits a curing catalytic action. Specific examples of the α-aminoacetophenone compound include (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane (Irgacure 369, trade name, manufactured by BASF Japan Ltd.) and 4- (methylthiobenzoyl) -1-methyl. -1-morpholinoethane (Irgacure 907, trade name, manufactured by BASF Japan Ltd.), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl]- A commercially available compound such as 1-butanone (Irgacure 379, trade name, manufactured by BASF Japan Ltd.) or a solution thereof can be used.

  Any oxime ester compound can be used as long as it is a compound that generates a basic substance by light irradiation. Examples of such oxime ester compounds include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, N-1919, and NCI-831 manufactured by Adeka. Further, compounds having two oxime ester groups in the molecule described in Japanese Patent No. 4,344,400 can also be suitably used.

  In addition, JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-A-2008-509967, Specific examples include carbazole oxime ester compounds described in JP2009-040762A and JP2011-80036A.

  Such a photobase generator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photobase generator in the resin composition of the present invention is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the thermosetting component. is there. In the case of 0.1 parts by mass or more, the development resistance contrast of the light irradiated part / non-irradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

  In the present invention, among the above, it is preferable to use an oxime ester photobase generator having a structure represented by the following general formula (I). Such an oxime ester photobase generator is one or more basic substances that can function as a catalyst for the addition reaction between a carboxyl group and a thermosetting component described later, when the molecule is cleaved by light irradiation such as ultraviolet light or visible light. Is a compound that produces Examples of basic substances include primary amines, secondary amines, and tertiary amines.

When the oxime ester photobase generator having the structure represented by the general formula (I) is used as the photobase generator, the deep curability of the resin composition is higher than when other photobase generators are used. Becomes better. In addition, since the oxime ester photobase generator generates both radicals and bases by light irradiation, the resin composition system contains a radical polymerizing agent such as an ethylenically unsaturated group. However, it is not necessary to include a radical photopolymerization initiator in addition to the photobase generator. As a result, it is possible to avoid the problem that sufficient light does not reach the depth due to the inclusion of both the photo radical polymerization initiator and the photo base generator. From the above, by using an oxime ester photobase generator, it is possible to form a pattern that is sufficiently cured to a deep portion and has a good cross-sectional shape.
In addition, when an oxime ester photobase generator having a structure represented by the general formula (I) is used, the selection of the heating time at the same heating temperature during the heat curing reaction after exposure (PEB process) The width can be increased. From these things, the workability | operativity and handleability of a resin composition improve.

  By using the oxime ester photobase generator having the structure represented by the general formula (I) as the photobase generator, the deep curability is good and the time management range of PEB can be widened. In addition, by using an oxime ester photobase generator, the occurrence of so-called hot fog, in which an undesired portion is cured by an addition reaction and cannot be developed, is suppressed. Although the detailed reason is not clear, as a possible reason, the oxime ester photobase generator having the structure represented by the general formula (I) does not generate a base in the state where it is not irradiated with light, and is irradiated with light. The base is generated only after the cleavage of the molecule. Therefore, it can be mentioned that the addition reaction using a base as a catalyst does not proceed in the unexposed area. On the other hand, even if it is a photobase generator, a compound having the property that the three-dimensional structure is changed by light irradiation and the basicity becomes strong, originally has a base such as an amine in the molecule, which is unexposed. It is thought that the addition reaction is caused even in the part. In such a case, the difference in the degree of cure of the resin composition due to the addition reaction between the exposed area and the unexposed area becomes small, and a clear contrast due to alkali development cannot be obtained, or heat fogging occurs. Become.

（式中、Ｒ^１は、水素原子、無置換または炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されたフェニル基、無置換または１個以上の水酸基で置換された炭素数１〜２０のアルキル基、１個以上の酸素原子で中断された該アルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数５〜８のシクロアルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数２〜２０のアルカノイル基又はベンゾイル基を表し、
Ｒ^２は、無置換または炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されたフェニル基、無置換または１個以上の水酸基で置換された炭素数１〜２０のアルキル基、１個以上の酸素原子で中断された該アルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数５〜８のシクロアルキル基、無置換または炭素数１〜６のアルキル基もしくはフェニル基で置換された炭素数２〜２０のアルカノイル基又はベンゾイル基を表す。）

(Wherein R ¹ is a hydrogen atom, an unsubstituted or alkyl group having 1 to 6 carbon atoms, a phenyl group substituted with a phenyl group or a halogen atom, unsubstituted or substituted with one or more hydroxyl groups. -20 alkyl group, the alkyl group interrupted by one or more oxygen atoms, unsubstituted, C1-C6 alkyl group or phenyl group substituted with C5-C8 cycloalkyl group, unsubstituted Or an alkanoyl group having 2 to 20 carbon atoms or a benzoyl group substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group,
R ² represents an unsubstituted or alkyl group having 1 to 6 carbon atoms, a phenyl group substituted with a phenyl group or a halogen atom, an unsubstituted or alkyl group having 1 to 20 carbon atoms substituted with one or more hydroxyl groups, The alkyl group interrupted by one or more oxygen atoms, unsubstituted or a cycloalkyl group having 5 to 8 carbon atoms substituted by an alkyl group having 1 to 6 carbon atoms or a phenyl group, unsubstituted or having 1 to 6 carbon atoms An alkanoyl group having 2 to 20 carbon atoms or a benzoyl group substituted with an alkyl group or a phenyl group is represented. )

（式中、Ｘは、水素原子、炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、フェニル基、フェニル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基又はジアルキルアミノ基により置換されている）、ナフチル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基又はジアルキルアミノ基により置換されている）を表し、Ｙ、Ｚはそれぞれ、水素原子、炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、ハロゲン基、フェニル基、フェニル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基又はジアルキルアミノ基により置換されている）、ナフチル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基又はジアルキルアミノ基により置換されている）、アンスリル基、ピリジル基、ベンゾフリル基、ベンゾチエニル基を表し、Ａｒは、結合か、炭素数１〜１０のアルキレン、ビニレン、フェニレン、ビフェニレン、ピリジレン、ナフチレン、チオフェン、アントリレン、チエニレン、フリレン、２，５−ピロール−ジイル、４，４’−スチルベン−ジイル、４，２’−スチレン−ジイルで表し、ｎは０か１の整数である。）Examples of commercially available oxime ester photobase generators include those listed above. Moreover, the photoinitiator which has two oxime ester groups in a molecule | numerator can also be used suitably, Specifically, the oxime ester compound which has a carbazole structure represented with the following general formula is mentioned.

(In the formula, X is a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, a phenyl group (an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms). A group, an amino group, an alkylamino group having an alkyl group having 1 to 8 carbon atoms or a dialkylamino group), a naphthyl group (an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms), And Y and Z are each a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, or a carbon number 1). Alkyl group having 1 to 8 alkoxy group, halogen group, phenyl group, phenyl group (alkyl group having 1 to 17 carbon atoms, alkoxy group having 1 to 8 carbon atoms, amino group, alkyl group having 1 to 8 carbon atoms) Group or a dialkylamino group), a naphthyl group (an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group having an alkyl group having 1 to 8 carbon atoms, or Represents an anthryl group, a pyridyl group, a benzofuryl group, a benzothienyl group, and Ar is a bond or alkylene having 1 to 10 carbon atoms, vinylene, phenylene, biphenylene, pyridylene, naphthylene, thiophene , Anthrylene, thienylene, furylene, 2,5-pyrrole-diyl, 4,4′-stilbene-diyl, 4,2′-styrene-diyl, and n is an integer of 0 or 1.)

  In particular, in the above general formula, X and Y are each a methyl group or an ethyl group, Z is a methyl group or a phenyl group, n is 0, Ar is a bond, phenylene, naphthylene, thiophene, or thienylene. It is preferable that

（式中、Ｒ^１１は、炭素原子数１〜４のアルキル基、または、ニトロ基、ハロゲン原子もしくは炭素原子数１〜４のアルキル基で置換されていてもよいフェニル基を表す。
Ｒ^１２は、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基、または、炭素原子数１〜４のアルキル基もしくはアルコキシ基で置換されていてもよいフェニル基を表す。
Ｒ^１３は、酸素原子または硫黄原子で連結されていてもよく、フェニル基で置換されていてもよい炭素原子数１〜２０のアルキル基、炭素原子数１〜４のアルコキシ基で置換されていてもよいベンジル基を表す。
Ｒ^１４は、ニトロ基、または、Ｘ^１−Ｃ（＝Ｏ）−で表されるアシル基を表す。Ｘ^１は、炭素原子数１〜４のアルキル基で置換されていてもよいアリール基、チエニル基、モルホリノ基、チオフェニル基、または、下記式で示される構造を表す。）

Moreover, the compound which can be represented by the following general formula can also be mentioned as a preferable carbazole oxime ester compound.

(Wherein, R ¹¹ represents an alkyl group or a nitro group, a halogen atom or a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms having 1 to 4 carbon atoms.
R ¹² represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkyl group or alkoxy group having 1 to 4 carbon atoms.
R ¹³ may be linked with an oxygen atom or a sulfur atom, and may be substituted with an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 4 carbon atoms which may be substituted with a phenyl group. Represents a good benzyl group.
R ¹⁴ represents a nitro group or an acyl group represented by X ¹ —C (═O) —. X ¹ represents an aryl group, a thienyl group, a morpholino group, a thiophenyl group, or a structure represented by the following formula, which may be substituted with an alkyl group having 1 to 4 carbon atoms. )

  In addition, carbazole oxime ester compounds described in the above-mentioned publications can also be used.

  Such oxime ester photobase generators may be used singly or in combination of two or more. The blending amount of the photobase generator in the alkali development type photocurable thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0. 1 to 30 parts by mass. In the case of 0.1 parts by mass or more, the development resistance contrast of the light irradiated part / non-irradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

[Photo radical polymerization initiator]
In addition to the photobase generator, the resin composition of the present invention may contain a photoradical polymerization initiator as long as the effects of the present invention are not impaired. As the photoradical polymerization initiator, a known photoradical polymerization initiator that generates radicals by light irradiation can be used. For example, alkylphenone photopolymerization initiators other than α-aminoacetophenone photopolymerization initiators that can function as the above-mentioned photobase generator, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, etc. Can do.

  Examples of the alkylphenone photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl. -Propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one and the like.

  Specific examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and bis (2,6-dimethoxy). And benzoyl) -2,4,4-trimethyl-pentylphosphine oxide. Examples of commercially available products include Lucilin TPO manufactured by BASF Japan and Irgacure 819 manufactured by BASF Japan.

  The compounding amount of these alkylphenone photopolymerization initiator and acylphosphine oxide photopolymerization initiator is 0 with respect to 100 parts by mass of the total amount of the urethane resin having a carboxyl group and the resin having a carboxyl group other than the urethane resin. It is preferable that it is 0.01-15 mass parts. If it is less than 0.01 parts by mass, the photocurability may be insufficient, and the coating properties such as chemical resistance may deteriorate. On the other hand, when the amount exceeds 15 parts by mass, the effect of reducing the outgas cannot be obtained, the light absorption on the surface of the coating film becomes intense, and the deep curability tends to decrease. More preferably, it is 0.5-10 mass parts.

  Examples of titanocene photopolymerization initiators include bis (cyclopentadienyl) -diphenyl-titanium, bis (cyclopentadienyl) -dichloro-titanium, and bis (cyclopentadienyl) -bis (2,3,4). , 5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium, and the like. Examples of commercially available products include Irgacure 784 manufactured by BASF Japan.

  It is preferable that the compounding quantity of a titanocene type photoinitiator is 0.01-15 mass parts with respect to 100 mass parts of total amounts of urethane resin which has a carboxyl group, and resin which has carboxyl groups other than a urethane resin. When it is less than 0.01 parts by mass, the photocurability on copper is insufficient, the coating film peels off, and the coating properties such as chemical resistance may be deteriorated. On the other hand, if it exceeds 15 parts by mass, the light absorption amount becomes excessively high and the deep curability may be deteriorated. More preferably, it is 0.5-10 mass parts.

  In addition to the photopolymerization initiator, a photoinitiator assistant and a sensitizer can be used. Photoinitiators, photoinitiators, and sensitizers that can be suitably used for photosensitive resin compositions include benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, and tertiary amine compounds. And xanthone compounds.

  Specific examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

  Specific examples of the acetophenone compound include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and the like.

  Specific examples of the anthraquinone compound include 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, and the like.

  Specific examples of the thioxanthone compound include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.

  Specific examples of the ketal compound include acetophenone dimethyl ketal and benzyl dimethyl ketal.

  Specific examples of the benzophenone compound include benzophenone, 4-benzoyldiphenyl sulfide, 4-benzoyl-4′-methyldiphenyl sulfide, 4-benzoyl-4′-ethyldiphenyl sulfide, and 4-benzoyl-4′-propyldiphenyl. And sulfides.

  Specifically, as the tertiary amine compound, for example, an ethanolamine compound, a compound having a dialkylaminobenzene structure, such as 4,4′-dimethylaminobenzophenone (Nisso Cure MABP manufactured by Nippon Soda Co., Ltd.), 4, Dialkylaminobenzophenone such as 4′-diethylaminobenzophenone (EAB manufactured by Hodogaya Chemical Co., Ltd.), 7- (diethylamino) -4-methyl-2H-1-benzopyran-2-one (7- (diethylamino) -4-methylcoumarin), etc. Dialkylamino group-containing coumarin compounds, ethyl 4-dimethylaminobenzoate (Kayacure EPA, manufactured by Nippon Kayaku Co., Ltd.), ethyl 2-dimethylaminobenzoate (Quantacure DMB, manufactured by International Bio-Synthetics), 4-dimethylamino Nobenzoic acid (n-butoxy) ethyl (Quantacure BEA manufactured by International Bio-Synthetics), p-dimethylaminobenzoic acid isoamyl ethyl ester (Kayacure DMBI manufactured by Nippon Kayaku Co., Ltd.), 2-dimethylhexyl 4-dimethylaminobenzoic acid (Esolol 507 manufactured by Van Dyk).

  Of these, thioxanthone compounds and tertiary amine compounds are preferred. In particular, the inclusion of a thioxanthone compound is preferable from the viewpoint of deep curability. Among them, it is preferable to include a thioxanthone compound such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.

  As a compounding quantity of such a thioxanthone compound, it is preferable that it is 20 mass parts or less with respect to 100 mass parts of total amounts of the urethane resin which has the said carboxyl group, and resin which has carboxyl groups other than a urethane resin. When the blending amount of the thioxanthone compound exceeds 20 parts by mass, the thick film curability is lowered and the cost of the product is increased. More preferably, it is 10 parts by mass or less.

  As the tertiary amine compound, a compound having a dialkylaminobenzene structure is preferable, and among them, a dialkylaminobenzophenone compound, a dialkylamino group-containing coumarin compound having a maximum absorption wavelength in the range of 350 to 450 nm, and ketocoumarins are particularly preferable. .

  As the dialkylaminobenzophenone compound, 4,4'-diethylaminobenzophenone is preferable because of its low toxicity. Dialkylamino group-containing coumarin compounds have a maximum absorption wavelength in the ultraviolet region of 350 to 410 nm, so they are less colored and use a colored pigment as well as a colorless and transparent cured coating, and a colored cured coating that reflects the color of the colored pigment itself Can be provided. In particular, 7- (diethylamino) -4-methyl-2H-1-benzopyran-2-one is preferable because it exhibits an excellent sensitizing effect on laser light having a wavelength of 400 to 410 nm.

  As a compounding quantity of such a tertiary amine compound, it is 0.1-20 mass parts with respect to 100 mass parts of total amounts of urethane resin which has a carboxyl group, and resin which has carboxyl groups other than urethane resin. preferable. When the amount of the tertiary amine compound is less than 0.1 parts by mass, a sufficient sensitizing effect tends not to be obtained. On the other hand, when it exceeds 20 parts by mass, light absorption on the surface of the coating film by the tertiary amine compound becomes violent, and the deep curability tends to decrease. More preferably, it is 0.1-10 mass parts.

These radical photopolymerization initiators, photoinitiator assistants, and sensitizers may be used singly or as a mixture of two or more.
The total amount of such radical photopolymerization initiator, photoinitiator assistant, and sensitizer is 35 parts by mass with respect to 100 parts by mass of the total amount of the urethane resin having a carboxyl group and the resin having a carboxyl group other than the urethane resin. The following is preferable. When it exceeds 35 parts by mass, the deep curability tends to decrease due to light absorption.

[Thermosetting component]
The thermosetting component has a functional group capable of addition reaction with a carboxyl group by heat. As the thermosetting component, for example, a compound having a cyclic (thio) ether group is preferable, and examples thereof include an epoxy resin and a polyfunctional oxetane compound.

  The epoxy resin is a resin having an epoxy group, and any known one can be used. Examples thereof include a bifunctional epoxy resin having two epoxy groups in the molecule, and a polyfunctional epoxy resin having many epoxy groups in the molecule. In addition, a hydrogenated bifunctional epoxy compound may be used.

  Examples of the epoxy compound include bisphenol A type epoxy resin, brominated epoxy resin, novolac type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, and alicyclic type. Epoxy resin, trihydroxyphenylmethane type epoxy resin, bixylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type epoxy resin, bisphenol A novolac type epoxy resin, tetraphenylolethane type epoxy resin, heterocyclic epoxy resin , Diglycidyl phthalate resin, tetraglycidyl xylenoyl ethane resin, naphthalene group-containing epoxy resin, epoxy resin having dicyclopentadiene skeleton, glycidyl methacrylate Relate copolymerization system epoxy resins, copolymerized epoxy resins of cyclohexylmaleimide and glycidyl methacrylate, and a CTBN modified epoxy resin.

  Other liquid bifunctional epoxy resins include vinylcyclohexene diepoxide, (3 ′, 4′-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylate, and (3 ′, 4′-epoxy-6′-methyl). And alicyclic epoxy resins such as (cyclohexylmethyl) -3,4-epoxy-6-methylcyclohexanecarboxylate. These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

  In addition, you may mix | blend well-known and usual compounds, such as a maleimide compound, a block isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a cyclocarbonate compound, an episulfide resin, as a thermosetting component.

  As a compounding amount of the thermosetting component, an equivalent ratio (carboxyl group: heat-reactive group such as epoxy group) of the urethane resin having a carboxyl group and a resin having a carboxyl group other than the urethane resin is 1: 0.1. It is preferably ˜1: 10. By setting the blending ratio in such a range, development becomes favorable and a fine pattern can be easily formed. The equivalent ratio is more preferably 1: 0.2 to 1: 5.

[Photosensitive monomer]
The resin composition of the present invention can contain a monomer having an ethylenically unsaturated group (referred to as a photosensitive monomer). The photosensitive monomer is a compound having one or more ethylenically unsaturated groups in the molecule. The photosensitive monomer assists the polymerization reaction of ethylenically unsaturated groups by irradiation with active energy rays. Due to the presence of the ethylenically unsaturated group, a radical polymerization reaction due to light occurs, a strong matrix is formed, and the occurrence of dripping at the time of heat curing after development can be suppressed. As the ethylenically unsaturated group, those derived from (meth) acrylate are preferable.

  Examples of the compound used as the photosensitive monomer include conventionally known polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, epoxy (meth) acrylate, and the like. . Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; N, N-dimethylacrylamide Acrylamides such as N-methylol acrylamide and N, N-dimethylaminopropyl acrylamide; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate and N, N-dimethylaminopropyl acrylate; hexanediol, trimethylolpropane, Polyhydric alcohols such as pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or the like; Polyhydric acrylates such as lenoxide adducts, propylene oxide adducts, or ε-caprolactone adducts; polyvalent acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide or propylene oxide adducts of these phenols Acrylates; glyceryl diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyglycerides of glycidyl ether such as triglycidyl isocyanurate; not limited to the above, polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, Directly acrylated polyol such as polyester polyol, or urethane acrylate via diisocyanate Acrylates and melamine acrylates, and at least one of each methacrylate corresponding to the acrylate.

  Furthermore, you may use the epoxy acrylate resin etc. which made acrylic acid react with polyfunctional epoxy resins, such as a cresol novolak-type epoxy resin, as a photosensitive monomer. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

  The compounding amount of the compound having an ethylenically unsaturated group in the molecule used as the photosensitive monomer is preferably 100 parts by mass of the total amount of the urethane resin having a carboxyl group and the resin having a carboxyl group other than the urethane resin. 1 to 50 parts by mass, more preferably 3 to 30 parts by mass. When the blending amount is less than 1 part by mass, a sufficient sagging prevention effect may not be obtained. On the other hand, when it exceeds 50 mass parts, a cured film may become weak.

(Polymer resin)
The resin composition of the present invention can be blended with conventionally known polymer resins for the purpose of improving the flexibility and dryness of the touch of the resulting cured product. Examples of the polymer resin include cellulose, polyester, phenoxy resin, polyvinyl acetal, polyvinyl butyral, polyamide, polyamideimide binder polymer, block copolymer, elastomer and the like. The above polymer resins may be used alone or in combination of two or more.

(Inorganic filler)
An inorganic filler can be blended in the resin composition of the present invention. The inorganic filler is used for suppressing the curing shrinkage of the cured product of the resin composition and improving properties such as adhesion and hardness. Examples of the inorganic filler include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, and Neuburg Examples include rich earth. The said inorganic filler may be used individually by 1 type, and may use 2 or more types together.

(Coloring agent)
Furthermore, a coloring agent can be mix | blended with the resin composition of this invention. As the colorant, conventionally known colorants such as red, blue, green, yellow, white, and black can be used, and any of pigments, dyes, and pigments may be used.

(Organic solvent)
In the resin composition of the present invention, an organic solvent can be used for preparing the resin composition or adjusting the viscosity 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. Such an organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

(Other optional ingredients)
If necessary, the resin composition of the present invention may further contain components such as a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber. As these, those known in the field of electronic materials can be used. In addition, the above resin composition includes known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, silicone-based, fluorine-based, polymer-based antifoaming agents and / or leveling agents, Known and commonly used additives such as silane coupling agents and rust preventives can be blended.

[Dry film]
The dry film of the present invention has a resin layer made of the resin composition of the present invention. The multilayer film may be a dry film having a layer made of a resin composition other than the resin composition of the present invention.
In forming a dry film, for example, the resin composition of the present invention is diluted with an organic solvent to have an appropriate viscosity, and is applied to a carrier film with a uniform thickness by a known technique such as a comma coater. Thereafter, drying is usually performed at a temperature of 50 to 130 ° C. for 1 to 30 minutes to form a resin layer on the carrier film.

  A plastic film is used as the carrier film. Although there is no restriction | limiting in particular about the thickness of a carrier film, Generally, it selects suitably in the range of 10-150 micrometers. After forming the resin layer on the carrier film, a peelable cover film may be further laminated on the surface of the resin layer.

[Flexible printed wiring board and manufacturing method thereof]
The flexible printed wiring board of the present invention is characterized by having a cured product composed of a photosensitive thermosetting resin composition or a resin layer of a dry film.
The method for producing a flexible printed wiring board of the present invention includes a step of forming a resin layer made of a photosensitive thermosetting resin composition on a flexible printed wiring board, a step of irradiating the resin layer with light in a pattern, and a resin layer. A step of heating, and a step of alkali-developing the resin layer to form at least one of a coverlay and a solder resist.

[Resin layer forming step]
In this step, at least one resin layer made of an alkali development type photocurable thermosetting resin composition is formed on the flexible printed wiring board.
Examples of the method for forming the resin layer include a coating method and a laminating method.
In the case of the application method, the alkali development type photocurable thermosetting resin composition is applied onto the flexible printed wiring board by a method such as screen printing and dried to form a resin layer.
In the case of the laminating method, first, an alkali development type photo-curable thermosetting resin composition is diluted with an organic solvent to adjust to an appropriate viscosity, applied onto a carrier film, and dried to produce a dry film having a resin layer. To do. Next, after bonding together so that a resin layer may contact a flexible printed wiring board with a laminator etc., a carrier film is peeled.

  Moreover, another layer can be laminated | stacked on a resin layer. The other layer is preferably made of an alkali development type photosensitive resin composition. As an alkali development type photosensitive resin composition, a well-known composition can be used, For example, the well-known composition for coverlays or a soldering resist can be used. Thus, by setting it as the laminated structure including another layer, the hardened | cured material which was further excellent in impact resistance and flexibility can be obtained.

[Light irradiation process]
This step activates the photobase generator contained in the resin layer by light irradiation in a negative pattern to cure the light irradiation part. In this step, the photobase generator is destabilized by the base generated in the light irradiation part, and the base is chemically proliferated, whereby the resin layer can be sufficiently cured to the deep part.

As the light irradiator, a direct writer, a light irradiator equipped with a metal halide lamp, or the like can be used. The patterned light irradiation mask is a negative mask.
As the active energy ray used for light irradiation, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photobase generator can be activated efficiently. If a laser beam in this range is used, either a gas laser or a solid laser may be used. Moreover, although the light irradiation amount changes with film thicknesses etc., it can generally be set as 100-1500 mJ / cm < ² >.

[Heating process]
In this step, after the light irradiation, the light irradiation part is cured by heating the resin layer. By this process, it is possible to cure to a deep part by the base generated in the light irradiation process. The heating temperature is, for example, 80 to 140 ° C. The heating time is, for example, 10 to 100 minutes.
Curing of the alkali development type photo-curable thermosetting resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, and therefore, distortion and curing shrinkage compared to the case where curing proceeds by a photoradical reaction. Can be suppressed.

[Development process]
In the development step, the unirradiated portion is removed by alkali development to form a negative patterned insulating film, particularly a coverlay and a solder resist.
The developing method can be a known method such as dipping. Further, as the developing solution, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solution such as tetramethylammonium hydroxide aqueous solution (TMAH) or a mixed solution thereof should be used. Can do.
Note that the insulating film may be further irradiated with light after the development step. For example, you may heat at 150 degreeC or more.

  Next, an example of a method for producing the flexible printed wiring board of the present invention from the resin composition of the present invention will be described based on the process diagram of FIG. FIG. 1 shows a case where the resin layer has a laminated structure, but it may be composed of only one layer.

In the laminating process of FIG. 1, a laminated structure composed of the resin layer 3 and the resin layer 4 is formed on the flexible printed wiring substrate 1 on which the copper circuit 2 is formed.
The resin layer 3 is made of the alkali development type photocurable thermosetting resin composition of the present invention containing a urethane resin having a carboxyl group, a resin having a carboxyl group other than the urethane resin, and a photobase generator.
The resin layer 4 is formed on the resin layer 3 and is a photosensitive heat containing a polyimide resin having one or more imide rings and one or more carboxyl groups in one molecule, a photobase generator, and a thermosetting component. It consists of a curable resin composition.

  In the light irradiation step of FIG. 1, a mask 5 is arranged on the resin layer 4 and light irradiation is performed in a negative pattern, thereby activating the photobase generator contained in each resin layer and curing the light irradiation portion. It is a process to do. The heating process of FIG. 1 is a process (PEB process) of curing the light irradiation part by heating the resin layer after the light irradiation process. The development process in FIG. 1 is a process in which an unirradiated portion is removed by developing with an alkaline aqueous solution, and a negative pattern layer is formed.

  In addition, the 2nd light irradiation process of FIG. 1 is a process for activating the remaining photobase generator as needed, and generating a base, and a thermosetting process is a pattern layer as needed. This is a process for sufficient heat curing.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example.

[Example 1, Reference Examples 1 to 5, Comparative Examples 1 to 4]
<Preparation of resin composition>
In accordance with the formulation shown in Table 1 below, the materials described in Examples, Reference Examples and Comparative Examples were respectively blended, premixed with a stirrer, kneaded with a three roll mill, and alkali-developable photocurable thermosetting resin. A composition was prepared. The values in the table are solids (parts by mass) unless otherwise specified.

<Resin layer formation process>
A flexible printed wiring substrate in which a circuit was formed with a copper thickness of 18 μm was prepared, and pre-treatment was performed using MEC CZ-8100. Thereafter, the flexible printed wiring board subjected to the pretreatment was coated with the resin compositions of Example 1, Reference Examples 1 to 5 and Comparative Examples 1 to 4 to 20 μm after drying by a liquid coating method. It was. Then, it dried at 80 degreeC and 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer. Thereafter, the film was irradiated with a negative pattern with an exposure amount of 500 mJ / cm ² using ORC HMW680GW (metal halide lamp, scattered light).

<Developability evaluation by temperature of PEB process>
The board | substrate which has the resin layer after the exposure obtained by the formation process of said resin layer was heat-processed for 80 degreeC 60 minutes, 90 degreeC 30 minutes, and 100 degreeC 15 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C., developed for 3 minutes, evaluated for developability, and evaluated for the width (minutes) of the developable heating time. The evaluation criteria are as follows.
○: Development is possible and the state of the coating is good.
× * 1: Pattern cannot be formed because the exposed area is dissolved in the developer.
× * 2: The pattern cannot be formed because the unexposed area does not dissolve in the developer.

<Evaluation of pattern shape after curing>
The board | substrate which has the resin layer after the exposure obtained by the formation process of said resin layer performed 90 degreeC 30 minute heat processing (PEB). Thereafter, the substrate was immersed in a 1% by mass aqueous sodium carbonate solution at 30 ° C. and developed for 3 minutes. Thereafter, it was heated at 150 ° C. for 60 minutes, and it was evaluated whether the pattern shape was sag after curing. The evaluation criteria are as follows. The obtained results are shown in Table 1 below.
A: The shape of the pattern is smooth and sharp.
○: No sagging in the pattern shape.
X: The pattern shape is sagging.

＊１：酸価４７ｍｇＫＯＨ／ｇ ポリウレタンアクリレート（共栄社化学製）
＊２：酸価５０ｍｇＫＯＨ／ｇ ポリウレタン樹脂（根上工業社製）
＊３：酸価６３ｍｇＫＯＨ／ｇ 酸変性ノボラック型エポキシアクリレート樹脂（日本化薬社製）
＊４：酸価１０４ｍｇＫＯＨ／ｇ ビスフェノールＡノボラック樹脂
＊５：トリメチロールプロパンＥＯ 変性トリアクリレート(東亞合成社製)
＊６：ビスフェノールＡ型エポキシ樹脂（三菱化学社製）
＊７：α−ヒドロキシアセトフェノン系光重合開始剤（ＢＡＳＦ社製）
＊８：光塩基発生剤（和光純薬社製）
＊９：オキシム系光重合開始剤（ＢＡＳＦ社製）

* 1: Acid value 47mgKOH / g Polyurethane acrylate (manufactured by Kyoeisha Chemical)
* 2: Acid value 50 mgKOH / g Polyurethane resin (Negami Kogyo Co., Ltd.)
* 3: Acid value 63 mgKOH / g Acid-modified novolak epoxy acrylate resin (Nippon Kayaku Co., Ltd.)
* 4: Acid value 104 mg KOH / g Bisphenol A novolak resin * 5: Trimethylolpropane EO modified triacrylate (manufactured by Toagosei Co., Ltd.)
* 6: Bisphenol A type epoxy resin (Mitsubishi Chemical Corporation)
* 7: α-hydroxyacetophenone photopolymerization initiator (BASF)
* 8: Photobase generator (Wako Pure Chemical Industries, Ltd.)
* 9: Oxime-based photopolymerization initiator (BASF)

  As is apparent from the evaluation results shown in Table 1, the photosensitive thermosetting resin compositions of Example 1 and Reference Examples 1 to 5 were subjected to post-exposure heat treatment at any of 80 ° C., 90 ° C., and 100 ° C. Even so, the developability was good. Moreover, there was no drooping in the pattern shape after curing, and a sharp shape was obtained.

[Examples 2 and 3 and Reference Examples 6 to 11]
<Preparation of resin composition>
In accordance with the formulation shown in Table 2 below, the materials described in Examples and Reference Examples were respectively blended, premixed with a stirrer, kneaded with a three-roll mill, and an alkali development type photocurable thermosetting resin composition was obtained. Prepared. The values in the table are solid contents (parts by mass) unless otherwise specified.

<Resin layer formation process>
A flexible printed wiring substrate in which a circuit was formed with a copper thickness of 18 μm was prepared, and pre-treatment was performed using MEC CZ-8100. Thereafter, the pre-treated flexible printed wiring board was coated with the resin compositions of Examples 2 and 3 and Reference Examples 6 to 11 to 20 μm after drying by a liquid coating method. Then, it dried at 80 degreeC and 30 minutes with the hot-air circulation type drying furnace, and formed the resin layer.

<Developability evaluation by PEB process time>
The resin layer obtained by the above resin layer formation step was irradiated with a negative pattern at an exposure amount of 500 mJ / cm ² with ORC HMW680GW (metal halide lamp, scattered light).
The substrate having the exposed resin layer was subjected to heat treatment at 90 ° C. for 30 minutes, 60 minutes, 70 minutes, and 80 minutes. Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30 ° C., developed for 3 minutes, evaluated for developability, and evaluated for the width (minutes) of the developable heating time. The evaluation criteria are as follows.
○: Development is possible and the state of the coating is good.
X: A pattern is not formed by development because the unexposed portion also undergoes a curing reaction.

<Preparation of composition for protective layer>
A resin composition for a protective layer used in the following patternability evaluation was prepared as follows. An acid value of 86 mgKOH / g Mw: 10,000 parts by weight of polyimide having a carboxyl group of 10000, 63.5 parts by weight of jER828, and 10 parts by weight of Irgacure OXE02, and after premixing with a stirrer, 3 pieces A resin composition for the protective layer was prepared by kneading with a roll mill.

<Patternability evaluation when used as an adhesive layer>
Using the resin compositions of Examples and Reference Examples, the resin composition obtained by preparing the composition for the protective layer is liquid on the dried resin layer obtained by the above resin layer forming step. Coating was performed so as to be 10 μm after drying by a coating method, and drying was performed at 80 ° C. for 30 minutes in a hot air circulation type drying furnace to form two resin layers. Thereafter, the film was irradiated with a negative pattern with an exposure amount of 500 mJ / cm ² using ORC HMW680GW (metal halide lamp, scattered light), and subjected to heat treatment at 90 ° C. for 30 minutes. Thereafter, the substrate was immersed in a 1% by mass aqueous sodium carbonate solution at 30 ° C., developed for 3 minutes, and patterned. After patterning, the cross-sectional shape was confirmed with an optical microscope and the shape was evaluated.
○: Undercut does not occur in the lower layer.
×: Large undercut occurs in the lower layer.
The results are shown in Table 2 below.

※１１：酸価４７ｍｇＫＯＨ／ｇ カルボキシル基含有ポリウレタンアクリレート、共栄社化学社製
※１２：酸価６３ｍｇＫＯＨ／ｇ 酸変性ノボラック型エポキシアクリレート樹脂（日本化薬社製）
※１３：酸価１０４ｍｇＫＯＨ／ｇ ビスフェノールＡノボラック樹脂
※１４：ビスフェノールＡ型エポキシ樹脂、ｊＥＲ８２８（三菱化学社製）
※１５：イルガキュアＯＸＥ−０２（ＢＡＳＦ社製）
※１６：ＮＣＩ−８３１（ＡＤＥＫＡ社製）
※１７：下記構造式で表される化合物

※１８：イルガキュア１８４（ヒドロキシルアルキルフェノン系光重合開始剤、ＢＡＳＦ社製）
※１９：イルガキュア９０７（アミノアルキルフェノン系光重合開始剤、ＢＡＳＦ社製）
※２０：ＷＰＲＧ−０１８（９−アンスリルメチル Ｎ，Ｎ’−ジエチルカルバメート）（和光純薬社製）

* 11: Acid value 47 mgKOH / g carboxyl group-containing polyurethane acrylate, manufactured by Kyoeisha Chemical Co., Ltd. * 12: Acid value 63 mgKOH / g acid-modified novolak epoxy acrylate resin (manufactured by Nippon Kayaku Co., Ltd.)
* 13: Acid value 104 mgKOH / g Bisphenol A novolac resin * 14: Bisphenol A type epoxy resin, jER828 (Mitsubishi Chemical Corporation)
* 15: Irgacure OXE-02 (BASF)
* 16: NCI-831 (made by ADEKA)
* 17: Compound represented by the following structural formula

* 18: Irgacure 184 (hydroxylalkylphenone photopolymerization initiator, manufactured by BASF)
* 19: Irgacure 907 (aminoalkylphenone photopolymerization initiator, manufactured by BASF)
* 20: WPRG-018 (9-anthrylmethyl N, N′-diethylcarbamate) (Wako Pure Chemical Industries, Ltd.)

As is apparent from Table 2 above, the resin composition according to Reference Examples 6 to 10 containing the oxime ester photobase generator having the structure represented by the general formula (I) of the present invention is the heating time in the PEB step. The selection range was wide, and the handleability was excellent.
In contrast, the resin compositions according to Examples 2 and 3 and Reference Example 11 that do not contain the oxime ester photobase generator having the structure represented by the general formula (I) are heated at 90 ° C. for 70 minutes or more. Then, even if it was an unexposed part, alkali development was not possible and pattern formation was impossible.
Moreover, even if the resin composition which concerns on Reference Examples 6-10 was located in the lower layer of the two-layer structure which has a protective layer which consists of a resin composition which absorbs light as an upper layer, sufficient deep part sclerosis | hardenability was shown.

DESCRIPTION OF SYMBOLS 1 Flexible printed wiring board 2 Copper circuit 3 Resin layer 4 Resin layer 5 Mask

Claims (8)

Urethane resin having a carboxyl group,
Resin having a carboxyl group other than urethane resin,
A photobase generator, and
Thermosetting component,
Only including,
The photobase generator comprises 9-anthrylmethyl N, N′-diethylcarbamate and / or (E) -1-piperidino-3- (2-hydroxyphenyl) -2-propen-1-one ; An alkali-developable photocurable thermosetting resin composition.   The alkali development type photocurable thermosetting resin composition according to claim 1, wherein the urethane resin having a carboxyl group has an ethylenically unsaturated group.   Furthermore, the alkali development type photocurable thermosetting resin composition of Claim 1 containing the monomer which has an ethylenically unsaturated group.   The alkali-developable photocurable thermosetting resin composition according to claim 1, wherein the thermosetting component is a cyclic ether compound.   2. The alkali development type photocurable thermosetting resin composition according to claim 1, which is used for a coverlay adhesive layer.   A dry film comprising a resin layer formed by applying and drying the alkali-developable photocurable thermosetting resin composition according to claim 1. A cured product obtained by curing the alkali-developable photocurable thermosetting resin composition according to claim 1 or the dry film according to claim 6 . A flexible printed wiring board comprising the cured product according to claim 7 .

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