JP2003005365A - Ultraviolet-curable resin composition and dry film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a UV-curable resin composition excellent in heat resistance of a cured body and capable of improving resistance to the heat of soldering when used as photo-soldering resist ink particularly for the production of a printed wiring board. SOLUTION: The UV-curable resin composition contains (A) a UV-curable resin having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, (B) an epoxy compound having two or more epoxy groups in one molecule, (C) a finely powdered polyimide resin, (D) a photopolymerization initiator and (E) a diluent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet curable resin composition which is developable with a dilute alkaline aqueous solution having ultraviolet curability and thermosetting property, and a dry film formed from the ultraviolet curable resin composition. In particular, the present invention relates to those having excellent solder heat resistance and being preferably used as a photo solder resist for manufacturing a printed wiring board.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high density of conductor patterns of various printed wiring boards for consumer use and industrial use, solder resist formation is required to have higher resolution and dimensional accuracy. It was Therefore, today, a method using a liquid photo solder resist ink is used instead of the screen printing method. These photo solder resists are generally disclosed in JP-A-61-243869.
JP-A-2-173747, JP-A-7-72624
As disclosed in Japanese Patent Application Laid-Open No. 9-235348 and Japanese Patent Application Laid-Open No. 9-235348, an ultraviolet curable resin composition prepared by adding an unsaturated bond group and a carboxyl group to a novolac type epoxy resin or an acrylic copolymer was used. It is a thing.

[0003]

Generally, a photosolder resist ink using the above-mentioned UV-curable resin composition is applied onto a printed board and then cured at a necessary portion by UV rays or the like. Unnecessary parts are removed by development. Then, the mounting component is mounted by a solder reflow method or the like.

However, with the recent progress of countermeasures against environmental problems, use of lead-free solder has come to be desired for mounting components, and as a result, the mounting temperature rises, which is higher in the photo solder resist ink. Solder heat resistance has been required.

The present invention has been made in view of the above points, and has excellent heat resistance of a cured product, and particularly improves solder heat resistance when used as a photo solder resist ink for producing a printed wiring board. It is an object of the present invention to provide an ultraviolet curable resin composition that can be used and a dry film comprising the ultraviolet curable resin composition.

[0006]

The ultraviolet curable resin composition according to claim 1 of the present invention comprises: An ultraviolet curable resin having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, B. An epoxy compound having two or more epoxy groups in one molecule, C.I. Finely powdered polyimide resin, D. A photopolymerization initiator and E.I. It is characterized in that it comprises a diluent.

According to a second aspect of the present invention, in the first aspect, the finely powdered polyimide resin C has a particle size of 0.1 to 50 μm.
It is characterized by being in the range of.

[0008] The invention of claim 3 is 0.5 to 40 in the total amount of the components of the ultraviolet curable resin composition of claim 1 or 2, wherein the finely powdered polyimide resin C excludes the organic solvent in the diluent E. It is characterized in that it is contained by weight%.

A dry film according to a fourth aspect of the present invention has a coating film obtained by drying the ultraviolet curable resin composition according to any one of the first to third aspects, on the surface of a support. It is characterized by being formed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

The ultraviolet curable resin composition of the present invention comprises an ultraviolet curable resin A having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, and two or more epoxy groups in one molecule. The epoxy compound B, the finely powdered polyimide resin C, the photopolymerization initiator D, and the diluent E which are essential components are contained. In particular, by containing the finely powdered polyimide resin C, the cured film has excellent heat resistance. It has excellent solder heat resistance when used for forming a solder resist for producing a printed wiring board.

As the fine powdery polyimide resin C, any fine powder of solid polyimide resin having an imide bond in the main chain can be used without any particular limitation. The smaller the particle size of the fine powdery polyimide resin C, the more it contributes to the improvement of heat resistance, and the particle size of 50 μm or less is preferably used. Further, if the particle size of 10 μm or less is used, particularly excellent performance is exhibited. The lower limit of the particle size is not particularly limited, but it is difficult to prepare a particle size smaller than 0.1 μm.
m is the practical lower limit.

The finely powdered polyimide may be finely powdered before it is incorporated into the ultraviolet curable resin composition, and is dispersed in the ultraviolet curable resin composition in the finely powdered state. Alternatively, it may be dissolved in the ultraviolet curable resin composition.

As the finely powdered polyimide resin, "AURUM" (registered trademark) is commercially available from Mitsui Chemicals, Inc., among which the grade "P" is especially preferred.
D400 ”,“ PD450 ”and“ PD500 ”have a particle size in the range of 20 to 30 μm and are preferably used. Further, preferably, these fine powdery polyimide resins are prepared to have a particle diameter of 10 μm or less by applying a well-known fine powdering method. In the case of pulverizing the polyimide resin, particularly if freeze-pulverization is performed, pulverization is easy, and a pulverized polyimide resin having a uniform particle size can be obtained.

Further, as such a fine powdery polyimide resin, one prepared by a precipitation polymerization method can be used.

The precipitation polymerization method is a method in which a polyamic acid solution is refluxed to cause an imidization reaction to proceed to precipitate a fine powdery polyimide resin.

Polyamic acid can be produced, for example, by dissolving an acid anhydride such as tetracarboxylic acid anhydride and a diamine in an aprotic polar solvent and holding the mixture at room temperature while stirring in an inert atmosphere. it can. At this time, as tetracarboxylic acid, for example, anhydrous 3,3 ′, 4,4 ′
-Benzophenone tetracarboxylic acid can be used. As the diamine, 4,4'-diaminodiphenyl ether (DPE), 4,4'-bis (4-aminophenoxy) biphenyl (BAPB), 1,4-bis (4-aminophenoxy) benzene (TPE-Q) ,
1,3-bis (4-aminophenoxy) benzene (TP
ER) or the like can be used. Further, as an aprotic polar solvent, N-methyl-2-pyrrolidone (NM
P), N, N-dimethylacetamide (DMAc), dimethylformamide (DMF) and the like can be used.

For the reflux of the polyamic acid solution, a reaction vessel equipped with a test tube between a separable flask and a reflux condenser was used, and the polyamic acid solution obtained as described above was placed in the separable flask. Toluene is added to and heated with stirring. At this time, water by-produced by the imidization reaction is trapped in a test tube outside the reaction system by azeotropic distillation with toluene, and toluene is returned to the flask due to overflow.

When such reflux is performed, the fine powdery polyimide resin is precipitated. The finely powdered polyimide resin thus obtained has high crystallinity and very excellent thermal characteristics.

The amount of the finely powdered polyimide resin C is preferably 0.5% by weight or more based on the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent in the diluent E. In this case, Has particularly excellent heat resistance. Further, the blending amount is preferably 40% by weight or less, and in this case, a resist layer obtained from the ultraviolet curable resin composition can obtain excellent surface gloss. It is particularly preferably 0.5 to 20% by weight, and optimum results are obtained in this range.

There is no particular limitation on the UV curable resin having a carboxyl group and two or more ethylenically unsaturated groups in one molecule which is the component A of the present invention, but the UV curable resin before exposure is not limited. The resin A is provided with solubility, dispersion or swellability in a dilute alkaline aqueous solution, and the exposed portion of the coating film of the composition of the present invention has sufficient solubility, dispersion or swellability in a dilute alkaline aqueous solution before and after exposure. In order to cause a change, it must have both a carboxyl group and two or more ethylenically unsaturated groups in the molecule as described above. The acid value derived from the carboxyl group in the UV curable resin A is 25 to 250 mg
KOH / g is preferable, and 25 is particularly preferable.
~ 150 mg KOH / g. The ethylenically unsaturated group is a backbone polymer in which two or a large number of photopolymerizable ethylenically unsaturated groups or groups having a photopolymerizable ethylenically unsaturated bond are introduced at the molecular ends or side chains. Good.

As such an ultraviolet curable resin A,
For example, a compound obtained by copolymerizing an ethylenically unsaturated monomer (a) having an epoxy group with another ethylenically unsaturated monomer (b) is added to an ethylenically unsaturated compound (d) having a carboxyl group. ) And a saturated or unsaturated acid anhydride (e) are reacted to obtain an ultraviolet-curable resin (A-1), and a carboxyl group in an epoxy compound (c) having two or more epoxy groups in one molecule. Of an ultraviolet curable resin (A-2), an acid anhydride copolymer (f) and an ethylenic compound, which are obtained by reacting an ethylenically unsaturated compound (d) having a hydroxyl group with a saturated or unsaturated acid anhydride (e) An ultraviolet curable resin (A-3) obtained by reacting with an alcohol (g) having an unsaturated group, and an ethylenically unsaturated compound (d) having a carboxyl group and an ethylenically unsaturated copolymerizable therewith Unit quantity (B) and the compound obtained by copolymerizing, ethylenically unsaturated monomer (a) is reacted obtained ultraviolet-curable resin having an epoxy group (A
-4) and the like can be mentioned, and these can be used alone or in combination.

Among the UV curable resins A having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, the component (a) used in (A-1) and (A-4) Examples of the ethylenically unsaturated monomer having an epoxy group include epoxycyclohexyl derivatives of acrylic acid or methacrylic acid, alicyclic epoxy derivatives of acrylate or methacrylate, and β-methylglycidyl acrylate or β-methylglycidyl methacrylate. These may be used alone or in combination. In particular, it is preferable to use glycidyl acrylate or glycidyl methacrylate that is widely used and easily available. As the ethylenically unsaturated monomer which is the component (b) used in (A-1) and (A-4), the component (a) and the component (A-) in the above (A-1) are also used.
In 4), any ethylenically unsaturated monomer copolymerizable with component (d) may be used, and it may be used in combination as necessary for adjusting photocurability and physical properties of the cured film.
Particularly, straight-chain or branched aliphatic, aromatic, or alicyclic (provided that a part of the rings may have an unsaturated bond) acrylic acid ester or methacrylic acid ester, hydroxyalkyl acrylate, or hydroxyalkyl methacrylate. , Alkoxyalkyl acrylates or alkoxyalkyl methacrylates, benzyl acrylates or benzyl methacrylates, and N-substituted maleimides such as N-phenylmaleimide, N-cyclohexylmaleimide and the like, which can be used alone or in combination. . These components (b) are particularly preferable in that it is easy to control the film hardness and oiliness of the ultraviolet curable resin, and the hardness of the resist finally formed.

As the epoxy compound having two or more epoxy groups in one molecule which is the component (c) used in (A-2), an appropriate epoxy resin or a polymerized epoxy compound is used alone or in combination. Can be used. In particular, triglycidyl isocyanurate, YX4000
(Made by Yuka Shell Epoxy Co., Ltd.), phenol novolac type epoxy resin, cresol novolac type epoxy resin,
Bisphenol A type epoxy resin and bisphenol A
-Novolak type epoxy resins and the like are desirable, and these can be used alone or in combination.

Examples of the ethylenically unsaturated monomer having a carboxyl group which is the component (d) used in (A-1), (A-2) and (A-4) include acrylic acid and methacrylic acid. , Crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2
-Methacryloyloxyethyl phthalic acid, β-carboxyethyl acrylate, acryloyloxyethyl succinate, methacryloyloxyethyl succinate,
2-propenoic acid, 3- (2-carboxyethoxy) -3-oxypropyl ester, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, Those having only one ethylenically unsaturated group such as 2-methacryloyloxyethylhexahydrophthalic acid, pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol penta Reaction of dibasic acid anhydride with polyfunctional acrylates and polyfunctional methacrylates having hydroxyl groups such as acrylate and dipentaerythritol pentamethacrylate. Is allowed, such as those obtained, there may be mentioned those having a plurality of ethylenically unsaturated groups, these can be used alone respectively, or in combination. Among these, those having only one carboxyl group are preferable, and particularly when acrylic acid or methacrylic acid is used alone or in combination, it is preferable to use acrylic acid or methacrylic acid or a mixture thereof as a main component. That is,
Since the ethylenically unsaturated group introduced by acrylic acid or methacrylic acid is excellent in photoreactivity, it is preferable to use acrylic acid or methacrylic acid as the ethylenically unsaturated monomer (d) having a carboxyl group. .

Examples of the saturated or unsaturated acid anhydride which is the component (e) used in (A-1) and (A-2) include succinic anhydride, methylsuccinic anhydride, maleic anhydride and citracone anhydride. Dibasic acid anhydrides such as acid, glutaric anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic acid anhydride, hexahydrophthalic anhydride and methylhexahydrophthalic anhydride, and Tribasic acid or more acid anhydrides such as trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, and methylcyclohexene tetracarboxylic acid anhydride can be used, and these can be used alone or in combination.

In the production of (A-1), the content of the epoxy group-containing ethylenically unsaturated monomer (a) is 40 in the total amount of the polymerizable monomer components used in the production of the copolymer.
It is preferably in the range of ˜95 mol%. This is 40
When the content is at least mol%, sufficient photocurability can be obtained, good sensitivity and resolution can be obtained in the pattern formation process, and the solder heat resistance of the finally formed solder resist can be further improved. You can A particularly preferred range is 50 to 95 mol%, and the solder resist formed in this range exhibits particularly excellent solder heat resistance and electrolytic corrosion resistance.

In the production of (A-1), the copolymer obtained by reacting the above (a) and (b) can be obtained by a known polymerization method such as solution polymerization or emulsion polymerization. Taking solution polymerization as an example, a mixture of the ethylenically unsaturated monomer consisting of the above-mentioned component (a) and component (b) is added to a polymerization initiator in a suitable organic solvent, and the mixture is added under a nitrogen atmosphere. Polymerization is carried out by a method of heating and stirring, an azeotropic polymerization method, or the like.

Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; and ethyl acetate.
Examples thereof include butyl acetate, cellosolve acetate, butyl cellosolve acetate, butyl carbitol acetate, acetic acid esters such as propylene glycol monomethyl ether acetate, and dialkyl glycol ethers. These can be used alone or in combination.

Examples of the polymerization initiator for the above-mentioned polymerization include hydroperoxides such as diisopropylbenzene hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy). ) -Dialkyl peroxides such as hexane,
Diacyl peroxides such as isobutyryl peroxide, ketone peroxides such as methylethylketone peroxide, alkyl peresters such as t-butylperoxyvibrate, peroxydicarbonates such as diisopropylperoxydicarbonate, azobis Azo compounds such as isobutyronitrile are mentioned, and these can be used alone or in combination. Further, a redox type initiator may be used as the polymerization initiator.

Further, in the production of (A-1) and (A-2), the compounding amount of the ethylenically unsaturated monomer (d) having a carboxyl group is (A-1) in the above copolymer. In the case of (A-2), the epoxy compound (c) is preferably in such an amount that the carboxyl group present in the component (d) is 0.7 to 1.2 mol per 1 mol of the epoxy group present. , Particularly preferably 0.9-1.
The range is 1 mol. In this range, it is possible to particularly reduce the residual amount of epoxy groups in the ultraviolet curable resin, suppress the thermosetting reaction under a heat drying condition such as preliminary drying, and prevent the deterioration of the developability after exposure. At the same time, the unreacted ethylenically unsaturated monomer (d) having a carboxyl group can be prevented from remaining.

Further, in the production of (A-1) and (A-2), the component (e) imparts an acid value to the UV-curable resin so that it can be redispersed and redissolved by a dilute alkaline aqueous solution. Used as the main purpose. The usage is
The acid value of the ultraviolet curable resin obtained by adding the acid anhydride is 2
It is preferable to select it in the range of 5-150 mgKOH / g. When the acid value is 25 mgKOH / g or more, good developability can be obtained.
When the amount is 0 mgKOH / g or less, residual carboxyl groups in the resist after thermosetting can be reduced, and good electrical characteristics, electrolytic corrosion resistance, water resistance, etc. of the solder resist can be maintained.
The optimum effect is obtained especially when the acid value is 40 to 100 mgKOH / g.

In addition, in the production of (A-1) and (A-2), the addition reaction of the ethylenically unsaturated monomer (d) having a carboxyl group and the saturated or unsaturated acid anhydride (e) is , Can be performed using a known method. For example,
Ethylenically unsaturated monomer having a carboxyl group (d)
The addition reaction is carried out by adding hydroquinone or hydroquinone monomethyl ether as a thermal polymerization inhibitor to the solvent solution of the copolymer and benzyldimethylamine as a catalyst,
Tertiary amines such as triethylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride, methyltriethylammonium chloride, triphenylstibine, etc. are added and mixed by stirring, and by a conventional method, preferably 60 to 150 ° C., particularly preferably 80 ~
The reaction is carried out at a reaction temperature of 120 ° C. The addition reaction of the saturated or unsaturated polybasic acid anhydride (e) can also be carried out by the same method as described above.

The acid anhydride copolymer (f) used in the production of (A-3) is, for example, a copolymer of maleic anhydride and an ethylenically unsaturated monomer, for example, styrene-malein. Acid copolymer (for example, SMA manufactured by Atchem Co., Ltd.
Series, etc.), methyl vinyl ether-maleic anhydride copolymer (for example, Gauntlet AN series manufactured by ISP, etc.), (meth) acrylic acid ester-maleic anhydride copolymer, alpha-olefin-maleic anhydride copolymer, anhydrous Examples thereof include a maleic acid-itaconic anhydride-other unsaturated monomer copolymer, and a maleic anhydride-other unsaturated monomer copolymer, and these may be used alone or in combination. In the present specification, when (meth) acrylic acid is used, acrylic acid and methacrylic acid are collectively referred to, and when (meth) acrylic is used, acryl is used.
And methacrylic are generic terms.

Examples of the alcohol (g) having an ethylenically unsaturated group which is reacted with the component (f) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include pentaerythritol di (meth) acrylate, trimethylolethane di (meth) acrylate, trimethylolpropane di (meth) acrylate, glycerin-1,3-di (meth) acrylate, trimethylolmethane di (meth) acrylate, and the like. , And these are used alone or in combination. The ratio of (g) reacted with the component (f) can be in any range. Moreover, you may use the alcohol which does not have an unsaturated group together with these. It is generated (A-
It is desirable that no carboxylic acid anhydride remains in 3). For example, it is possible to prevent the carboxylic acid anhydride from remaining by adjusting the amount of the alcohols or the like used. As the reaction method of the above (f) and (g), for example, it can be obtained by heating in a suitable solvent such as ethers and aromatic hydrocarbons. When carrying out this reaction, the above-mentioned catalyst and polymerization inhibitor may be used.

The copolymer obtained by reacting the above (b) and (d) in the production of (A-4) is the same as that used in the known polymerization method, for example, the production of (A-1). It can be obtained using a similar method. In addition, in this copolymer,
A known method can also be used for the reaction of adding the ethylenically unsaturated monomer having an epoxy group (a), for example, the component (d) or (e) in the production of (A-1) and (A-2). ) The method used for the addition reaction of the component can be adopted. In the production of (A-4), the amount of the epoxy group-containing ethylenically unsaturated monomer (a) used is such that the carboxyl group remains in the produced (A-4) and a sufficient acid value is obtained. Must remain.

The ultraviolet curable resin A (for example, (A-1) to (A-4)) used in the present invention can be used alone or in combination, but the compounding amount thereof is the same as that of the ultraviolet curable resin composition. In order to ensure good sensitivity and working characteristics and good physical properties of the finally formed resist,
It is desirable that the amount is 10 to 80% by weight in the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent in the diluent E that is mixed at the same time.

Examples of the epoxy compound B having two or more epoxy groups in one molecule include a sparingly solvent-soluble epoxy compound and a general-purpose solvent-soluble epoxy compound, which can be used alone or in combination. In particular, triglycidyl isocyanurate, YX4000
(Made by Yuka Shell Epoxy Co., Ltd.), phenol novolac type epoxy resin, cresol novolac type epoxy resin,
Bisphenol A type epoxy resin and bisphenol A
-Novolac type epoxy resin or the like is desirable. The blending amount of the component B in the ultraviolet curable resin composition is 0.1 to 50% by weight based on the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent in the diluent E to be blended at the same time. Is desirable, and by setting it to 0.1% by weight or more, the solder resistance, plating resistance, etc. of the cured coating film can be further improved,
Further, when the amount is 50% by weight or more, the developability can be further improved.

As the photopolymerization initiator D, for example, benzoin and its alkyl ethers, acetophenone, 2,
Acetophenones such as 2-dimethoxy-2-phenylacetophenone, anthraquinones such as 2-methylanthraquinone, thioxanthones such as 2,4-dimethylthioxanthone, ketals such as acetophenone dimethyl ketal, benzophenone, 4-benzoyl-4′- Benzophenones or xanthones such as methyldiphenyl sulfide, those containing a nitrogen atom such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, and 2,4,6- Trimethylbenzoyldiphenylphosphine oxide and the like are listed, and these are known as benzoic acid-based compounds or tertiary amine-based compounds such as p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester and 2-dimethylaminoethylbenzoate. The photopolymerization accelerator and the sensitizer may be used in combination. These photopolymerization initiators are blended individually or in combination with each other as appropriate.

For example, as a sensitizer for the laser exposure method, 7
Coumarin derivatives such as diethylamino-4-methylcoumarin, other carbocyanine dyes, xanthene dyes and the like can be appropriately selected, and the UV curable resin composition of the present invention can be cured with visible light or near infrared rays. However, as long as it has ultraviolet curability, those using these are also included.

The blending amount of the photopolymerization initiator D in the ultraviolet curable resin composition is such that the organic solvent in the diluent E is blended at the same time in order to obtain a good balance between the photocurability and the physical properties of the obtained solder resist. It is preferably 0.1 to 30% by weight in the total amount of the components of the ultraviolet composition excluding the solvent.

As the diluent E, a photopolymerizable monomer or an organic solvent can be used alone or in combination. Examples of the photopolymerizable monomer include various acrylate monomers such as 2-hydroxyethyl (meth) acrylate and methacrylate monomers. The photopolymerizable monomers can be used alone or in combination with each other.

Examples of the organic solvent include linear, branched, secondary or polyhydric alcohols such as ethanol, propyl alcohol, isopropyl alcohol, hexanol and ethylene glycol, and ketones such as methyl ethyl ketone and cyclohexanone, and the like. Aromatic hydrocarbons such as toluene and xylene, petrochemical aromatic mixed solvents such as Swazol series (manufactured by Maruzen Petrochemical Co., Ltd.), Solvesso series (manufactured by Exxon Chemical Co.) and cellosolves, cellosolves such as butyl cellosolve, And carbitols such as carbitol and butyl carbitol,
And propylene glycol alkyl ethers such as propylene glycol methyl ether, and polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether, and acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, and dialkyl glycol ethers. These may be used alone or in combination with each other as appropriate.

The above-mentioned photopolymerizable monomer imparts photopolymerizability by diluting the ultraviolet curable resin A or the like to make it easy to apply and adjusting the acid value. In addition, the organic solvent dissolves and dilutes the ultraviolet curable resin A and the like so that the liquid can be applied as a liquid and is dried to form a film.

The component having photopolymerizability such as a photopolymerizable monomer as the above-mentioned diluent E does not necessarily have to be added to the ultraviolet curable resin composition, but when the component is added, the total amount thereof is diluted. It is desirable that the content is 50% by weight or less based on the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent that is similarly compounded as the agent E, which causes the surface tackiness of the dry coating film to be too strong. It is possible to prevent stains and the like of the negative mask when the negative mask on which the pattern is drawn is directly applied to the surface of the dried coating film for exposure.

On the other hand, the organic solvent used as the diluent E, like the above-mentioned photopolymerizable monomer, is an essential component of the ultraviolet curable resin composition of the present invention which can be developed with a dilute aqueous alkali solution, and can be rapidly dried during temporary drying. It must be selected so that it will not volatilize and remain in the dried coating film. The blending amount of the organic solvent in the ultraviolet curable resin composition is not particularly limited, but it is desirable to blend 5 to 99.5% by weight based on the total amount of the components of the composition. Good coatability of the product can be maintained. In addition, since the suitable blending amount varies depending on the coating method, it is necessary to appropriately adjust it according to the coating method.

In addition to the above-mentioned components, the ultraviolet-curable resin composition of the present invention comprises, for example, tolylene diisocyanate, morpholine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate-based compounds blocked with caprolactam, oxime, malonic acid ester and the like. Blocked isocyanate, thermosetting components such as melamine, amino resins such as n-butylated melamine resin, isobutylated melamine resin, butylated urea resin, butylated melamine urea co-condensation resin, benzoguanamine co-condensation resin, and UV curing. Epoxy acrylate or UV curable epoxy methacrylate, eg bisphenol A type,
Phenol novolac type, cresol novolac type, alicyclic epoxy resin with acrylic acid or methacrylic acid added, diallyl phthalate resin, phenoxy resin,
A polymer compound such as a melamine resin, a urethane resin, or a fluororesin can be appropriately added.

If necessary, the above ultraviolet curable resin composition contains epoxy resin curing agents and curing accelerators, fillers and colorants, silicone and acrylate copolymers,
Leveling agents, and adhesion-imparting agents such as silane coupling agents, thixotropic agents, polymerization inhibitors, antihalation agents, flame retardants, defoaming agents, various additives such as antioxidants and the like for improving dispersion stability. Several parts by weight of a surfactant, a polymer dispersant, etc. may be added.

The ultraviolet-curable resin composition of the present invention is prepared, for example, by a known kneading method using a triple roll, a ball mill, a sand mill or the like for the respective components and additives. In that case, a part of the components A to E, for example, a part of the E component and the B component are previously mixed and dispersed, and separately from this, a part of the A, D, E and C components. It is also possible to employ a method of mixing and dispersing in advance and mixing and preparing so as to have a blending composition of the ultraviolet curable resin composition of the present invention at the time of use. The method of forming a resist pattern on a substrate using the ultraviolet curable resin composition as a resist ink is not particularly limited. The most common method among them is as follows.

For example, in order to volatilize the organic solvent as a diluent after applying the ultraviolet curable resin composition (resist ink) on the substrate by a dipping method, spray, spin coater, roll coater, curtain coater or screen printing. For example, preliminary drying is performed at 60 to 120 ° C.
Next, apply a negative mask with a pattern directly or indirectly to the surface of the dried coating, and use a chemical lamp, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, xenon lamp, or metal halide lamp to irradiate ultraviolet rays. After irradiation, a pattern is formed by development, and the epoxy compound is cured by heating at 120 to 180 ° C. for about 30 to 90 minutes, for example, to improve the film strength, hardness and chemical resistance of the resist.

The alkaline solution used in the developing step is an aqueous sodium carbonate solution, an aqueous potassium carbonate solution,
Ammonium carbonate aqueous solution, sodium hydrogen carbonate aqueous solution, potassium hydrogen carbonate aqueous solution, ammonium hydrogen carbonate aqueous solution,
Examples thereof include sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonium hydroxide aqueous solution, and lithium hydroxide aqueous solution. In addition to the above alkalis, organic amines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine can be used, and these can be used alone or in combination. . As the solvent of the alkaline solution, not only water but also a mixture of water and a hydrophilic organic solvent such as lower alcohols can be used.

It is also possible to form a dry film comprising a support and a dry film resist by forming a film of the ultraviolet curable resin composition of the present invention on the surface of a support to form a so-called dry film resist. In this case, the thickness of the film is preferably 10 to 100 μm, and the support is preferably a film of polyethylene terephthalate or the like having a thickness of 5 to 100 μm. The coating film of the ultraviolet curable resin composition is preferably formed by coating the support film with the ultraviolet curable resin composition and drying.

[0053]

EXAMPLES The present invention will be described below based on examples, but the present invention is not limited thereto. In addition, all "parts" and "%" shown below are based on weight.

[Preparation of UV-curable resin solution] Glycidyl methacrylate 70 was placed in a four-necked flask equipped with a reflux condenser, a thermometer, a glass tube for nitrogen substitution and a stirrer.
Parts, 30 parts of methyl methacrylate, 100 parts of carbitol acetate, 0.2 parts of lauryl mercaptan, 3 parts of azobisisobutyronitrile, and heated under a nitrogen stream,
Polymerization was carried out at 80 ° C. for 5 hours with stirring to obtain a 50% copolymer solution. Next, in the above 50% copolymer solution,
Hydroquinone (0.05 parts), acrylic acid (37 parts), and dimethylbenzylamine (0.2 parts) were added to carry out an addition reaction at 100 ° C. for 24 hours, and subsequently, tetrahydrophthalic anhydride (45 parts) and carbitol acetate (79 parts) were added, 100
5 hours corresponding to the above-mentioned component (A-1)
A 0% UV curable resin solution was obtained.

[Fine powder polyimide resin A] Grade “PD” of “AURUM” (registered trademark) manufactured by Mitsui Chemicals, Inc.
400 ”was used.

When a SEM photograph of this fine powdery polyimide resin A was taken, the particle size was 20 to 30 μm.

[Fine Powder Polyimide Resin B] A fine powder polyimide A was further pulverized by freeze pulverization and used.

When the SEM photograph of this fine powdery polyimide resin B was taken, the particle size was 10 μm or less.

[Fine powder polyimide resin C] anhydrous 3,
3 ', 4,4'-benzophenone tetracarboxylic acid 0.
10 mol and 0.10 mol of 4,4'-diaminodiphenyl ether were added to N-methyl-2-pyrrolidone 50
A polyamic acid solution was obtained by stirring in 0 mL at room temperature for 24 hours under nitrogen gas.

To 500 mL of this polyamic acid solution was added 100 mL of toluene, and the mixture was refluxed for 4 hours while stirring at 360 rpm in a reaction vessel equipped with a test tube between a separable flask and a reflux condenser to give a finely powdered polyimide. Resin C was allowed to settle.

The precipitated fine powdery polyimide resin C was separated by filtration and purified by washing with a reaction solvent, methanol and acetone.

When an SEM photograph of this fine powdery polyimide resin C was taken, the particle size was 50 to 60 μm.

[Fine Powder Polyimide Resin D] N, N-dimethylacetamide was used in place of N-methyl-2-pyrrolidone as a solvent when preparing a polyamic acid solution, and other than the case of fine powder polyimide resin C. Similarly, a finely powdered polyimide resin D was obtained.

When the SEM photograph of this fine powdery polyimide resin D was taken, the particle size was 20 to 30 μm.

[Fine powder polyimide resin E] 1,4-bis (4-aminophenoxy) benzene was used in place of 4,4′-diaminodiphenyl ether as a diamine when preparing a polyamic acid solution, and N-methyl was used as a solvent. -2
-Using dimethylformamide instead of pyrrolidone, and otherwise doing the same as in the case of finely powdered polyimide resin C,
Finely powdered polyimide resin E was obtained.

When a SEM photograph of this fine powdery polyimide resin E was taken, the particle size was 4 to 5 μm.

[Examples 1 to 11 and Comparative Example 1] The UV-curable resin solution produced in the above-mentioned synthesis example was kneaded with the compounding ingredients of the respective compositional compositions shown in Table 1 by a three-roll mill,
To 11 and Comparative Example 1 were obtained liquid ultraviolet curable resin compositions developable with a dilute aqueous alkali solution. The following test methods evaluated the respective performances of the respective ultraviolet curable resin compositions and the printed wiring boards on which the solder resist was finally formed.

[0068]

[Table 1]

(Note 1) Epoxy compound with an epoxy equivalent of 195 Epoxy compound manufactured by Epoxy Co., Ltd. (Note 2) Triglycidyl isocyanurate (Note 3) manufactured by Nissan Chemical Industries, Ltd. with an epoxy equivalent of 100 Dainippon Ink Chemicals with an epoxy equivalent of 214 Industrial cresol novolac type resin (* 4) Ciba Geigy photopolymerization initiator (* 5) Monsanto leveling agent (* 6) Maruzen Sekiyu's aromatic solvent UV curable resin composition In order to confirm the performance of the printed wiring board manufactured by, a test piece was created by sequentially performing the following steps (I) to (V).

(I) <Coating Step> A copper clad laminate made of a glass epoxy base material of a copper foil having a thickness of 35 μm and a printed wiring having a pattern formed by previously etching the ultraviolet curable resin composition. The entire surface of the substrate was applied by screen printing to form a resist ink layer on the surface of the substrate.

(II) <Preliminary Drying Step> After the coating step, preliminary drying was carried out for 20 minutes at 80 ° C. in order to volatilize the solvent in the resist ink layer on the surface of the substrate to obtain a dried coating film having a thickness of 20 μm. .

(III) <Exposure Step> Thereafter, a mask having a pattern is directly applied to the surface of the dried coating film, and the ultraviolet rays of the optimum exposure amount in each ultraviolet curable resin composition are irradiated to dry the surface of the substrate. The coating was selectively exposed.

(IV) <Developing Step> In the dry coating film after the exposing step, the selectively unexposed portion is removed by developing with a sodium carbonate aqueous solution as a developing solution, and the substrate is exposed and cured. The resulting dry coating pattern was formed.

(V) <Post-baking step> The substrate on which the pattern of the dried and hardened coating film obtained in the development step is formed is heated at 150 ° C. for 30 minutes to cure the dried coating film. I got a test piece.

The following evaluations were performed on the test pieces obtained in the above steps. The results are shown in Tables 6 and 7.

-Resolution- The state of formation of a resist pattern formed by a mask pattern composed of concentric circles having a line width and a line spacing of 40 μm was observed.

The evaluation method of resolution is as follows. X: No pattern was formed. Δ: The pattern was formed, but a part of the pattern had a slight resin residue or lack. ◯: A pattern was formed, but there was a slight unevenness in the uniformity between the lines and the line width. A: A sharp pattern could be obtained.

-Solder Heat Resistance-LONCO 3355-11 (water-soluble flux manufactured by London Chemical Co.) was used as a flux, the test piece was first coated with the flux, and then this was applied at 280 ° C.
It was immersed for 15 seconds in the molten solder bath and then washed with water. After performing this cycle once or three times, the degree of surface whitening was observed. In addition, a cellophane adhesive tape peeling test by cross-cut was performed in accordance with JIS D 0202, and a change in adhesion state was observed.

The evaluation method of surface whitening is as follows. X: Remarkably whitened. Δ: Whitening was observed. ◯: Slight whitening was observed. A: No abnormality occurred.

The method of evaluating the adhesion is as follows. X: Blistering or peeling of the resist occurred without performing a cross-cut test. Δ: Peeling occurred in the cross-cut portion during tape peeling. ◯: Slight peeling occurred in the cross-cut portion when the tape was peeled off. ⊚: No peeling of the cross-cut portion occurred.

-Pencil Hardness- The pencil hardness is measured by using Mitsubishi High Uni (manufactured by Mitsubishi Pencil Co., Ltd.).
It was measured and evaluated according to JIS K 5400.

-Surface Gloss- The surface gloss was evaluated by visually observing the resist surface. The evaluation criteria are as follows. X: The surface had no gloss at all. (Triangle | delta): Both the surface gloss and the color development of the coloring pigment were in the permissible range, but they were not particularly excellent. ◯: The surface exhibited sufficient gloss and the coloring of the coloring pigment was excellent, but there was slight unevenness in color. ⊚: The surface exhibited sufficient gloss, and the coloring pigment contained therein was excellent in color development and had no color unevenness.

-Solvent resistance- 2-propanol and 1,1,1 at room temperature for 1 hour
-Dipped in trichloroethane, the substrate was observed and evaluated.

The solvent resistance evaluation method is as follows. ○: Those that do not cause abnormalities. Δ: A slight change is seen. X: Peeling is seen in the coating film.

-Acid Resistance- It was immersed in 10% hydrochloric acid for 1 hour at room temperature, and the substrate was observed and evaluated.

The evaluation method of acid resistance is as follows. ○: Those that do not cause abnormalities. Δ: A slight change is seen. X: Peeling is seen in the coating film.

-Gold Plating Resistance- Using commercially available electroless nickel plating baths and electroless gold plating baths, test pieces were plated and the adhesion state of the coating film was observed.

The evaluation method of gold plating resistance is as follows. ○: No change at all. Δ: There is no change in appearance, but some peeling is observed when the tape is peeled off. X: The coating film was found to be floating, and peeling was observed when the tape was peeled off.

-Electrical Corrosion Resistance- Instead of the test piece, an IPC B-25 comb-shaped electrode B coupon was used to fabricate an evaluation substrate under the above conditions, and a bias voltage of DC 100 V was applied to the comb electrode.
C, 90% R.C. H. Under the conditions, the presence or absence of migration after 500 hours was confirmed and evaluated.

The evaluation method of electrolytic corrosion resistance is as follows. ◯: Migration cannot be confirmed at all. Δ: Only slight migration can be confirmed. ×: Migration has occurred.

[0091]

[Table 2]

As can be seen from Table 2, the ultraviolet curable resin compositions of Examples 1 to 11 were more than those of Comparative Example 1.
Improved solder heat resistance.

The smaller the particle size of the finely powdered polyimide resin, the more improved the soldering heat resistance. Further, the compounding amount of the finely powdered polyimide resin is the ultraviolet curable resin composition excluding the organic solvent in the diluent E. 0.5 of all ingredients
By setting the content to -40% by weight, a resist layer having excellent solder heat resistance and surface gloss was obtained.

[0094]

As described above, the ultraviolet curable resin composition according to claim 1 of the present invention is An ultraviolet curable resin having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, B. An epoxy compound having two or more epoxy groups in one molecule, C.I. Fine powder polyimide resin, D.I. A photopolymerization initiator and E.I. Since it contains a diluent, the cured product has excellent heat resistance, and can improve solder heat resistance particularly when used as a photo solder resist ink for printed wiring board production. sex,
It also has good performances required for resists such as high level, surface gloss, adhesion, solvent resistance, gold plating resistance, and electrical decoration resistance.

According to a second aspect of the present invention, in the first aspect, the finely powdered polyimide resin C has a particle size of 0.1 to 50 μm.
Since it is within the range, the heat resistance of the cured product can be further improved.

The invention of claim 3 is the same as in claim 1 or 2, wherein the finely powdered polyimide resin C is 0.5 to 40 in the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent in the diluent E. Since it is contained by weight%, the heat resistance of the cured product can be further improved and the glossiness can be improved.

The dry film according to claim 4 of the present invention is for forming a coating film obtained by drying the ultraviolet curable resin composition according to any one of claims 1 to 3 on the surface of a support. , The cured product has excellent heat resistance,
When used as a photo solder resist ink for producing a printed wiring board, it is possible to improve solder heat resistance.

Continued front page    F term (reference) 2H025 AA04 AA10 AB11 AC01 AD01                       BC13 BC42 BC82 BC83 BC85                       BD03 BD23 CA00 CB25 CC03                       EA08 FA17                 4J036 AA01 FB01 FB14 HA02 JA10                 5E314 AA27 AA29 AA32 AA36 CC07                       CC15 DD07 FF05 FF19 GG10                       GG11 GG14

Claims (4)

[Claims] 1. A. An ultraviolet curable resin having a carboxyl group and two or more ethylenically unsaturated groups in one molecule, B. An epoxy compound having two or more epoxy groups in one molecule, C.I. Finely powdered polyimide resin, D. A photopolymerization initiator and E.I. An ultraviolet-curable resin composition comprising a diluent. 2. The particle size of the finely powdered polyimide resin C is 0.1.
The ultraviolet curable resin composition according to claim 1, wherein the ultraviolet curable resin composition is in the range of 50 μm. 3. A fine powder polyimide resin C is contained in an amount of 0.5 to 40% by weight based on the total amount of the components of the ultraviolet curable resin composition excluding the organic solvent in the diluent E. The ultraviolet curable resin composition according to 1 or 2. 4. A dry film, characterized in that a film obtained by drying the ultraviolet curable resin composition according to any one of claims 1 to 3 is formed on the surface of a support.