JP6709020B2 - Photocurable thermosetting resin composition, cured product thereof, and printed wiring board - Google Patents

Description

The present invention relates to a photocurable thermosetting resin composition, a cured product thereof, and a printed wiring board. More specifically, it relates to a photocurable thermosetting resin composition which is excellent in developability, surface curability, resolution and solder heat resistance and can be alkali-developed by a solventless non-contact exposure method, a cured product thereof, and a printed wiring board. ..

At present, liquid photosensitive resin compositions are widely used as resist materials used for permanent coatings in the production of printed wiring boards. In consideration of environmental issues, the development is mainly of the alkaline development type using an aqueous alkaline solution. As an alkali development type resist material using such an alkaline aqueous solution, for example, in Patent Document 1, a photosensitive resin obtained by adding an acid anhydride to an addition product of a novolac type epoxy compound and an unsaturated monobasic acid, a photopolymerization A liquid resin composition comprising an initiator, a diluent and an epoxy compound is disclosed.

JP-A-61-243869

Almost all of the alkali development type photoresist materials currently used in the production of printed wiring boards are of the contact exposure type, in which a negative film is brought into contact with a tack-free coating film obtained by drying after coating. It is a liquid resin composition. However, in such a contact exposure type liquid resin composition, since an organic solvent is used as a diluent, a drying step of about 30 minutes at a temperature of about 80° C. is required, and a large amount of organic solvent is used during drying. Since it is released into the atmosphere, there is a problem that productivity and workability are deteriorated and work environment and global environment are deteriorated.

On the other hand, as a method capable of solving such a problem, there is a non-contact exposure type liquid resin composition using a liquid photopolymerizable monomer without using an organic solvent as a diluent. However, the conventional non-contact exposure type liquid resin composition has a problem that the surface curability of the resist is lowered due to the reaction inhibition by oxygen in the photoreaction.
Further, in the non-contact exposure type liquid resin composition as described above, no solvent is used when synthesizing a photosensitive resin in which an acid anhydride is added to an adduct of a novolac type epoxy compound and an unsaturated monobasic acid. The addition reaction is slow because it is necessary, and as a result of the unreacted acid anhydride remaining in the synthesized resin varnish, the unreacted acid anhydride remaining in the resin varnish is added later, such as an epoxy resin. However, there is a problem that the developing property is deteriorated by causing a thermosetting reaction with.

Therefore, the object of the present invention was made to solve the problems of the non-contact exposure type liquid resin composition as described above, and its main purpose is to provide a non-contact exposure type liquid resin composition. Even if it exists, it exists in providing the photocurable thermosetting resin composition which can develop alkali, which can exhibit more excellent developability, surface curability, and resolution.
Another object of the present invention is to provide a printed wiring board having a cured product excellent in various properties such as solder heat resistance and a coating film made of the cured product.

As a result of intensive research aimed at achieving the above-mentioned object, the inventor has found that the above-mentioned problems can be solved by the following constitution, and has completed the present invention.

That is, the photocurable thermosetting resin composition of the present invention comprises (A) a reaction product of (a) a novolac type epoxy compound and (b) an unsaturated monocarboxylic acid, and (c) a saturated or unsaturated polybasic compound. The unreacted (c) saturated or unsaturated polybasic by reacting with an acid anhydride to react an unreacted (c) saturated or unsaturated polybasic acid anhydride with (d) a hydroxyl group-containing monomer. An active energy ray-curable resin varnish obtained by eliminating an acid anhydride, (B) a photopolymerization initiator, or a mixture of a photopolymerization initiator and a sensitizer, and (C) a thermosetting component. It is characterized by that.

In the photocurable thermosetting resin composition of the present invention, the sensitizer as the component (B) preferably contains at least one selected from thioxanthone compounds and amine compounds.

In the photocurable thermosetting resin composition of the present invention, the (C) thermosetting component is preferably a compound having a cyclic (thio)ether group.

The cured product of the present invention is characterized by being obtained by photocuring and then thermosetting any of the above photocurable thermosetting resin compositions.

The printed wiring board of the present invention is characterized by having a coating film made of the above cured product.

According to the present invention, the unreacted saturated or unsaturated polybasic acid anhydride is eliminated by using the hydroxyl group-containing monomer, so that even in the case of a non-contact exposure type liquid resin composition, more excellent development is achieved. It is possible to provide an alkali-developable photocurable thermosetting resin composition capable of exhibiting the properties, surface curability and resolution. As a result, by using the photocurable thermosetting resin composition of the present invention, it is possible to provide a printed wiring board having a cured product excellent in various properties such as solder heat resistance and a coating film comprising the cured product. Becomes

3 is a graph showing the relationship between the absorption peak and the wave number showing the change with time of the reaction of the phenol novolac type epoxy resin and acrylic acid in Synthesis Example 1. 5 is a graph showing the relationship between the absorption peak and the wave number showing the change over time in the reaction between the hydroxyl group and tetrahydrophthalic anhydride in Synthesis Example 1. 5 is a graph showing the relationship between the wave number and the absorption peak after the introduction of HEA (2-hydroxyethyl acrylate) in Synthesis Example 1.

Hereinafter, the photocurable thermosetting resin composition of the present invention will be specifically described.
The photocurable thermosetting resin composition according to the present invention (hereinafter, also referred to as “resin composition”) is a reaction product of (A) (a) a novolac type epoxy compound and (b) an unsaturated monocarboxylic acid. By reacting (c) saturated or unsaturated polybasic acid anhydride with unreacted (c) saturated or unsaturated polybasic acid anhydride and (d) hydroxyl group-containing monomer. It includes an active energy ray-curable resin varnish (hereinafter also referred to as “(A) resin varnish”) obtained by eliminating (c) saturated or unsaturated polybasic acid anhydride in the reaction.

When a non-contact exposure type liquid resin composition is used, it is necessary to remove the solvent from the step of synthesizing the resin varnish (A). However, if no solvent is used from the synthesis stage of the resin varnish (A), the reaction product of (a) the novolac type epoxy compound and (b) the unsaturated monocarboxylic acid, and (c) the saturated or unsaturated polybasic acid anhydride The progress of the reaction with is slowed, and as a result, a part of the saturated or unsaturated polybasic acid anhydride (c) remains in the resin varnish (A) in an unreacted state. When the resin varnish (A) is used as a component of the resin composition while the unreacted (c) saturated or unsaturated polybasic acid anhydride remains, the epoxy compound blended in the composition together with the resin varnish (A). And the like, and the unreacted (c) saturated or unsaturated polybasic acid anhydride undergoes a curing reaction, thereby deteriorating the developability of the resin composition.
In this respect, the photocurable thermosetting resin composition of the present invention is prepared by synthesizing an unreacted (c) saturated or unsaturated polybasic acid anhydride in the resin varnish (A) so that the unreacted resin does not remain after the resin synthesis. The (c) saturated or unsaturated polybasic acid anhydride of the reaction is reacted with the (d) hydroxyl group-containing monomer. As a result, the unreacted (c) saturated or unsaturated polybasic acid anhydride does not remain in the (A) resin varnish, and thus the resin obtained without reacting with the epoxy compound or the like incorporated in the composition The composition may exhibit better developability, surface curability and resolution. As a result, the photocurable thermosetting resin composition of the present invention is effective as a composition suitable for a non-contact exposure type liquid resin composition.

Here, in the present invention, instead of reacting the (c) saturated or unsaturated polybasic acid anhydride with the (d) hydroxyl group-containing monomer in the resin synthesis process in the (A) resin varnish, the (A) resin is used. After the resin in the varnish is synthesized, (c) saturated or unsaturated polybasic acid anhydride is reacted with (d) a hydroxyl group-containing monomer, and (c) saturated or unsaturated polybasic residue remains during the resin synthesis. It is preferable to eliminate unreacted acid anhydride. This is because when the (d) hydroxyl group-containing monomer is added during the resin synthesis process in the (A) resin varnish, the (d) hydroxyl group-containing monomer first reacts with the (c) saturated or unsaturated polybasic acid anhydride. And (a) the reaction product of the novolac type epoxy compound and (b) the unsaturated monocarboxylic acid, and (c) the saturated or unsaturated polybasic acid anhydride become insufficient, and this (A) resin This is because the developability of the resin composition using the varnish is reduced.

That is, in the photocurable thermosetting resin composition of the present invention, the unreacted (c) saturated or unreacted by blending the (d) hydroxyl group-containing monomer after the resin synthesis, not in the resin synthesis process in the (A) resin varnish. Since it is reacted with the unsaturated polybasic acid anhydride, it is possible to obtain a non-contact exposure type resin composition which is more excellent in developability than ever.

The photocurable thermosetting resin composition of the present invention contains (B) a photopolymerization initiator or a mixture of a photopolymerization initiator and a sensitizer.

In the present invention, even when the photopolymerization initiator is used alone, the inside is sufficiently cured, but in order to further improve the surface curability, it is preferable to use a sensitizer in combination with the photopolymerization initiator.
Examples of the sensitizer include thioxanthone compounds and amine compounds. Thioxanthone compounds are preferable from the viewpoint of deep-part curability. Further, amine compounds are preferable because they capture oxygen, which is a factor that inhibits the radical reaction, and have excellent surface curability.
When a thioxanthone compound or an amine compound is used as the sensitizer, a photopolymerization initiator other than the thioxanthone compound and the amine compound is used, and the photopolymerization initiator is not particularly limited.

<(A) Resin varnish>
The photocurable thermosetting resin composition of the present invention comprises (a) a reaction product of a novolac type epoxy compound and (b) an unsaturated monocarboxylic acid, and (c) a saturated or unsaturated polybasic acid anhydride. The unreacted (c) saturated or unsaturated polybasic acid anhydride is eliminated by reacting the unreacted (c) saturated or unsaturated polybasic acid anhydride with (d) hydroxyl group-containing monomer. The active energy ray curable resin varnish (A) is used.

The above-mentioned (A) resin varnish is one in which a saturated or unsaturated polybasic acid anhydride is further reacted with a hydroxyl group generated by an esterification reaction of an epoxy group of a polyfunctional novolac type epoxy compound and a carboxyl group of an unsaturated monocarboxylic acid. And, since the large number of free carboxyl groups are added to the side chain of the backbone polymer produced by the former esterification reaction by the latter reaction, development with an alkaline aqueous solution becomes possible, and at the same time, after development, When the coating film is post-heated, a thermosetting reaction is caused between the epoxy compound having two or more epoxy groups in one molecule added as a thermosetting compounding component and the free carboxyl group of the side chain. Then, a solder resist film having excellent properties such as heat resistance, solvent resistance, acid resistance, plating resistance, adhesiveness, electrical characteristics, hardness of the coating film can be obtained.
Moreover, the suitable range of the acid value of the said (A) resin varnish is 40-160 mgKOH/g, More preferably, it is 50-140 mgKOH/g. When the acid value is 40 mgKOH/g or more, the alkali solubility becomes better. Further, when the acid value is 160 mgKOH/g or less, the characteristics as a resist such as the alkali resistance of the cured film and the electric characteristics are favorable, which is preferable.

The (A) resin varnish is a reaction product of a novolac type epoxy compound and an unsaturated monocarboxylic acid described later, a dibasic acid anhydride such as phthalic anhydride, or an aroma such as trimellitic anhydride or pyromellitic anhydride. It is obtained by reacting with a group polycarboxylic acid anhydride. In this case, a resin varnish obtained by reacting 0.15 mol or more of the acid anhydride per one hydroxyl group contained in the reaction product of the novolac type epoxy compound and the unsaturated monocarboxylic acid is suitable.
When the number of ethylenically unsaturated bonds present in one molecule of the epoxy compound is small, the photocuring reaction is slow, so it is desirable to use a novolac type epoxy compound as a raw material, but bisphenol is used for the purpose of reducing the viscosity of the resin composition. An A type epoxy compound can also be used.

Typical examples of the above novolac type epoxy compound include phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, etc. A compound as obtained can be used. Examples of the unsaturated monocarboxylic acid include a reaction product of acrylic acid, methacrylic acid, cinnamic acid, a saturated or unsaturated dibasic acid anhydride, and (meth)acrylates having one hydroxyl group in one molecule. These can be used alone or in combination of two or more, but from the viewpoint of photocurability, acrylic acid or methacrylic acid is preferable, and acrylic acid is more preferable.
In addition, in this specification, (meth)acrylate is a general term for acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

Further, as the above polybasic acid anhydrides, typical examples are maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride. , Dibasic acid anhydrides such as endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, methyltetrahydrophthalic anhydride; trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride Aromatic polyvalent carboxylic acid anhydrides such as compounds; and other incidental compounds such as 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride A polycarboxylic acid anhydride derivative or the like can be used.

Typical examples of the hydroxyl group-containing monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, N-methyl acrylamide, and water-soluble monomers such as methacrylates corresponding to the acrylate; and diethylene glycol monoacrylate. , Triethylene glycol monoacrylate, propylene glycol monoacrylate, dipropylene glycol monoacrylate, tripropylene glycol monoacrylate, polypropylene glycol monoacrylate, trimethylolpropane diacrylate, glycerin diglycidyl ether diacrylate, glycerin triglycidyl ether triacrylate, penta Erythritol triacrylate, or each methacrylate corresponding to the above-mentioned acrylate is mentioned. In particular, it is preferable to use 2-hydroxyethyl acrylate (HEA) from the viewpoint of dilutability and curability.

The hydroxyl group-containing monomer as described above is used alone or as a mixture of two or more kinds. A suitable range of the amount used is 5 to 100 parts by mass, preferably 10 to 30 parts by mass with respect to 100 parts by mass of the (A) resin varnish.

Here, the hydroxyl group-containing monomer is a compound that dilutes the resin varnish (A) so that it can be easily applied and imparts photopolymerizability. Among the water-soluble monomer and the water-insoluble monomer, the water-soluble monomer is blended. If the ratio is large, the solubility in the alkaline aqueous solution will be good, but if it is used extremely excessively, the water resistance will be lost in the completely cured resist material, so the combined use of water-insoluble monomers is an effective means. Further, if the amount of the water-insoluble monomer used in combination is too large, the water-insoluble monomer becomes hardly soluble in the alkaline aqueous solution. Therefore, the content of the water-insoluble monomer is preferably 100% by mass or less of the resin varnish (A). Above all, the heavy use of water-soluble monomers is effective without lowering the subsequent characteristics.

<(B) Photopolymerization initiator or mixture of photopolymerization initiator and sensitizer>
The photocurable thermosetting resin composition of the present invention uses (B) a photopolymerization initiator or a mixture of a photopolymerization initiator and a sensitizer. As the photopolymerization initiator, one or more photopolymerization initiators selected from the following groups can be used. Further, as an example of a mixture of a photopolymerization initiator and a sensitizer, one or more photopolymerization initiators selected from the following group and one or more sensitizers selected from the following group: Mixtures of combinations of can be used.

Examples of the photopolymerization initiator include benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2 ,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1[4-(methylthio)phenyl]-2 -Acetophenones such as morpholinopropan-1-one; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and other anthraquinones; acetophenone dimethyl ketal, benzyldimethyl Ketals such as ketals; benzophenones such as benzophenone or xanthones. The preferable range of the amount of the photopolymerization initiator used is 0.2 to 30 parts by mass, preferably 2 to 20 parts by mass with respect to 100 parts by mass of the resin varnish (A).

Examples of the sensitizer include thioxanthone compounds and amine compounds.

Specific examples of the thioxanthone compound include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone. The thioxanthone-based compound is preferable not only in terms of the above-mentioned deep-curing property, but also because it has an absorption wavelength on the long wavelength side, from the viewpoint of compatibility with the colorant.

The compounding amount of such a thioxanthone compound is preferably 5 parts by mass or less with respect to 100 parts by mass of the resin varnish (A). When the compounding amount of the thioxanthone compound is 5 parts by mass or less, the thick film curability is further improved and the cost of the product is reduced. It is more preferably 2 parts by mass or less.

Specific examples of the amine compound include an ethanolamine compound and a compound having a dialkylaminobenzene structure. For example, commercially available products are 4,4′-dimethylaminobenzophenone (Nissocure MABP manufactured by Nippon Soda Co., Ltd.), 4 , 4'-diethylaminobenzophenone (EAB manufactured by Hodogaya Chemical Co., Ltd.) and the like, 7-(diethylamino)-4-methyl-2H-1-benzopyran-2-one (7-(diethylamino)-4- Dialkylamino group-containing coumarin compounds such as methylcoumarin), ethyl 4-dimethylaminobenzoate (Kayacure EPA manufactured by Nippon Kayaku Co., Ltd.), ethyl 2-dimethylaminobenzoate (Quantacure DMB manufactured by International Bio-Synthetics). , 4-dimethylaminobenzoic acid (n-butoxy)ethyl (International Bio-Synthetics, Quantacure BEA), p-dimethylaminobenzoic acid isoamyl ethyl ester (Kayakyu DMBI manufactured by Nippon Kayaku Co., Ltd.), 4-dimethyl 2-Ethylhexyl aminobenzoate (Esolol 507 manufactured by Van Dyk) and the like can be mentioned.

The compounding amount of such an amine compound is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin varnish (A). When the compounding amount of the amine compound is 0.1 part by mass or more, the surface curability is further improved. Further, when the amount is 5 parts by mass or less, it is possible to obtain the sensitizing effect including the internal curability and at the same time suppress the deterioration of the physical properties of the coating film. It is more preferably 0.1 to 2 parts by mass.

The total amount of the photopolymerization initiator and the sensitizer is preferably 20 parts by mass or less with respect to 100 parts by mass of the resin varnish (A). When it is 20 parts by mass or less, it is possible to suppress deep-part curability and deterioration of physical properties due to the photopolymerization initiator remaining in the coating film.

Since these photopolymerization initiators and sensitizers absorb a specific wavelength, the sensitivity may be lowered in some cases, and they may act as an ultraviolet absorber. However, these are not only used for the purpose of improving the sensitivity of the resin composition. If necessary, it absorbs light of a specific wavelength to improve the photoreactivity of the surface, and changes the resist line shape and opening to vertical, tapered, or inversely tapered, and the processing accuracy of line width and opening diameter. Can be improved.

<(C) Thermosetting component>
The photocurable thermosetting resin composition of the present invention contains (C) a thermosetting component in order to impart heat resistance. Examples of the thermosetting component used in the present invention include melamine resins, amine resins such as benzoguanamine resins, blocked isocyanate compounds, cyclocarbonate compounds, polyfunctional epoxy compounds, polyfunctional oxetane compounds, episulfide resins, melamine derivatives, bismaleimide, and oxazine. Known and commonly used thermosetting resins such as compounds, oxazoline compounds and carbodiimide resins can be used. Particularly preferred is the (C) thermosetting component having two or more cyclic ether groups and/or cyclic thioether groups (hereinafter abbreviated as cyclic (thio)ether groups) in the molecule.
The thermosetting component (C) of the present invention can be used alone or in combination of two or more.

The thermosetting component having a plurality of cyclic (thio)ether groups in the molecule is a compound having a plurality of 3-, 4-, or 5-membered ring cyclic (thio)ether groups in the molecule. Examples thereof include compounds having a plurality of epoxy groups, that is, polyfunctional epoxy compounds, compounds having a plurality of oxetanyl groups in the molecule, ie, polyfunctional oxetane compounds, compounds having a plurality of thioether groups in the molecule, that is, episulfide resins.
Examples of the compound having a plurality of epoxy groups in the molecule include dicyclopentadiene (DCPD) type epoxy resin, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin. Examples thereof include resins, cresol novolac type epoxy resins, N-glycidyl type epoxy resins, alicyclic epoxy resins, and other epoxy compounds having two or more epoxy groups in one molecule. Alternatively, a small amount of a known epoxy curing accelerator may be used in combination therewith to accelerate the reaction. The photocurable thermosetting resin composition containing such a thermosetting component (C) is applied, exposed, and developed, and then the coating film is post-heated to accelerate the polymerization of the photocurable resin component and the above. (C) Through copolymerization with a thermosetting component, various properties such as heat resistance, solvent resistance, acid resistance, plating resistance, adhesion, electrical characteristics and hardness of the resulting resist film can be improved, It is particularly useful as a solder resist. The above-mentioned (C) thermosetting component may be mixed with the above-mentioned photocurable resin composition in advance (one-component type), but since it easily thickens, it is used before application to a circuit board blank. At this time, it is desirable to use a mixture of both (two-component type). In the present invention, in particular, by using a dicyclopentadiene (DCPD) type epoxy resin, it is possible to reduce the viscosity of the resin composition without using a solvent and to realize high density of the printed wiring board by thinning the film. preferable. When a dicyclopentadiene (DCPD) type epoxy resin is used, the viscosity of the resin composition can be lowered, so that the leveling is improved and the surface gloss is improved.
The blending amount of the thermosetting component (C) is 5 to 100 parts by mass, preferably 10 to 40 parts by mass with respect to 100 parts by mass of the resin varnish (A).

The photocurable thermosetting resin composition of the present invention further comprises, if necessary, known fillers such as barium sulfate, silicon oxide, talc, clay and calcium carbonate, phthalocyanine blue, phthalocyanine green and titanium oxide. , Known additives such as carbon black and other commonly used colorants, defoaming agents, adhesion promoters or leveling agents, or known and commonly used polymerizations of hydroquinone, hydroquinone monomethyl ether, pyrogallol, tertiary butyl catechol, phenothiazine, etc. Inhibitors may be added.

The photocurable thermosetting resin composition of the present invention, for example, is applied to the entire surface by a screen printing method, a roll coater method, or a curtain coater method on a printed wiring board substrate, and an active energy ray is applied through a resist pattern film. After irradiating and curing the necessary portion, the unexposed portion is melted with an alkaline aqueous solution and then cured by heating, whereby a desired solder resist film can be formed.

As the alkaline aqueous solution used for the development, an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, or the like can be used. A low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp or a metal halide lamp is suitable as an irradiation light source for photo-curing. In addition, a laser beam or the like can also be used as an actinic ray for exposure.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following, "parts" and "%" are based on mass unless otherwise specified.

[Synthesis Example 1 (Synthesis of Resin Varnish 1)]
116.7 g of phenol novolac type epoxy resin (DEN 431 manufactured by Dow Chemical Co., Ltd.) was weighed in a 500 cc three-neck separable flask, and 52.8 g (1.1 equivalent) of acrylic acid and 0.07 g of phenothiazine were added thereto. Tetramethylammonium chloride (0.2 g) was added, and the mixture was stirred at 105°C under a reflux condition while blowing air at 0.5 L/min.
At 105° C. for 4 hours, the peak of the carboxyl group of acrylic acid in the vicinity of 1710 cm ⁻¹ disappeared and after 6 hours there was no significant change (see FIG. 1), so the reaction was almost completed under these conditions.
Next, 60.8 g of tetrahydrophthalic anhydride (0.6 equivalent to the hydroxyl group) was added, and after stirring and reaction at 100° C. for 6 hours, HEA (2-hydroxyethyl acrylate) 86.7 g was added as a diluent. A resin varnish 1 which was liquid at room temperature was synthesized. Wherein the reaction between a hydroxyl group and tetrahydrophthalic anhydride confirms the reaction the disappearance of the peak in the vicinity of anhydride specific 1780 cm ^-1 and near 1830,1860cm ^-1, 100 ℃, acid anhydride unreacted 6 hours Things were confirmed (see FIG. 2). However, it was confirmed that the unreacted acid anhydride had completely disappeared after the addition of HEA (see FIG. 3). The acid value of the resin varnish 1 obtained by synthesis was 91 mKOH/g.

[Synthesis Example 2 (Synthesis of Resin Varnish 2)]
In a 500 cc three-neck separable flask, 116.7 g of phenol novolac type epoxy resin (DEN 431 by Dow Chemical Co.) and polyethylene glycol #200 diacrylate (A-200 by Shin Nakamura Chemical Co., Ltd.) 33. 3 g and phenoxyethyl acrylate (Kyoeisha Chemical Co., Ltd. light ester PO) 33.3 g were weighed out, and 52.8 g (1.1 equivalent) of acrylic acid, 0.07 g of phenothiazine, and 0.2 g of tetramethylammonium chloride were placed therein. In addition, under reflux conditions, stirring was performed at 105° C. while blowing air at 0.5 L/min. Next, a resin varnish 2 was synthesized by the same method as in Synthesis Example 1 except that HEA was finally added.

<Preparation of Photocurable Thermosetting Resin Compositions of Examples 1 to 4 and Comparative Examples 1 and 2>
The components shown in Table 1 below were mixed in the proportions (parts by mass) described in the table to prepare a photocurable thermosetting resin composition.
In order to avoid shortening the pot life due to the reaction between the resin varnishes 1 and 2 synthesized above and the epoxy resin, it is divided into a composition on the photocurable component side and a composition on the thermosetting component side ( Each composition was dispersed by a three-roll mill manufactured by Inoue Seisakusho.

<Preparation of cured coating>
Next, the prepared composition on the side of the photocurable component and the composition on the side of the thermosetting component are mixed, and the composition is applied by screen printing onto a copper-clad laminate having a pattern-etched 35 μm copper foil in advance and dried. Without using the projection exposure apparatus UFX-2223B (lamp 2Kw) manufactured by USHIO INC., a predetermined amount of light was irradiated.
After that, development was performed using a 1% by mass sodium carbonate solution at 30° C. under a spray pressure of 0.2 MPa/cm ² for 60 seconds, circulating water washing for 20 seconds, and running water for 20 seconds, and a hot air circulation type drying furnace at 150° C. 60 A cured coating film was obtained by post-curing for minutes. The characteristics were evaluated using the cured coating film of the obtained photocurable thermosetting resin composition.

*1: 19.5 parts by mass of 2-hydroxyethyl acrylate is contained in the resin varnish 1.
*2: Photopolymerization initiator, 2,2-dimethoxy-1,2-diphenylethan-1-one (manufactured by BASF)
*3: Thioxanthone sensitizer, 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd.)
*4: Amine sensitizer, 4,4'-diethylaminobenzophenone (Hodogaya Chemical Co., Ltd.)
*5: Barium sulfate, B-30 (manufactured by Sakai Chemical Industry Co., Ltd.)
*6: FASTOGEN Blue FA5380 (manufactured by DIC Corporation)
*7: Cromophytal Yellow AGR (Pigment Yellow 147) (manufactured by BASF)
*8: Defoaming/leveling agent (Kyoeisha Chemical Co., Ltd.)
*9: Dicyclopentadiene type epoxy resin (made by ADEKA Corporation)
*10: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation)
*11: Bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation)
*12: Polyfunctional acrylate (manufactured by Nippon Kayaku Co., Ltd.)

(Evaluation methods)
<Developability>
The photocurable thermosetting resin compositions of Examples and Comparative Examples were screen-printed on a patterned copper foil substrate, dried at 80° C. for 30 minutes, and a 1% by mass carbonic acid solution at 30° C. The time until the solder resist was completely dissolved by using a sodium aqueous solution at a spray pressure of 0.2 MPa/cm ² was measured. The obtained results are shown in Table 2 below.
◯: Less than 10 seconds △: 10 seconds or more, less than 20 seconds ×: 20 seconds or more

<Surface hardening>
The photocurable thermosetting resin compositions of the examples and comparative examples were screen-printed on a patterned copper foil substrate, and the substrate was exposed using a high-pressure mercury lamp (short arc lamp) exposure device. exposing the solder resist pattern by a predetermined exposure amount ^{(500mJ / cm 2, 750mJ /} cm 2, 1000mJ / cm 2), after exposure, wipe the resist surface with cloth, rag is determined by whether colored. The obtained results are shown in Table 2 below.
◯: The waste is not stained Δ: A slight green color is transferred ×: The resist surface is not cured and the waste is soiled with a liquid component

<Resolution on copper>
The photocurable thermosetting resin compositions of Examples and Comparative Examples were applied on the entire surface of a copper foil of a copper-clad laminate by screen printing, and as an exposure pattern, the line/space was 30/30 to 100/100 μm in length and width. Using a negative for drawing a line, a predetermined amount of light (500 mJ/cm ² , 1000 mJ/cm ² ) was irradiated using an exposure device equipped with a high pressure mercury lamp (short arc lamp). After the exposure, a 1% by mass Na ₂ CO ₃ aqueous solution at 30° C. was developed for 60 seconds under a spray pressure of 0.2 MPa/cm ² and heat-cured at 150° C. for 60 minutes to obtain a cured coating film. .. The minimum residual line of the cured coating film of the obtained photocurable thermosetting resin composition was determined using an optical microscope adjusted to 200 times, and this was defined as the resolution on copper. The obtained results are shown in Table 2 below.

<Resolution on substrate>
The photocurable thermosetting resin compositions of Examples and Comparative Examples were screen-printed on a glass epoxy base material from which the copper foil of the copper-clad laminate was removed by etching, and an exposure pattern of 30 lines/spaces was applied. Using a negative for drawing vertical/horizontal lines of /30 to 100/100 μm, a light amount of 1000 mJ/cm ² was irradiated using an exposure device equipped with a high pressure mercury lamp (short arc lamp). After the exposure, a 1% by mass Na ₂ CO ₃ aqueous solution at 30° C. was developed for 60 seconds under a spray pressure of 0.2 MPa/cm ² and heat-cured at 150° C. for 60 minutes to obtain a cured coating film. .. The minimum residual line of the cured coating film of the obtained photocurable thermosetting resin composition was determined using an optical microscope adjusted to 200 times, and this was defined as the resolution on the substrate. The obtained results are shown in Table 2 below.

<Solder heat resistance>
According to the test method of JIS C 60068-2-58, the evaluation board coated with the rosin-based flux was immersed in a solder bath set to 260° C. for 30 seconds in advance, the flux was washed with denatured alcohol, and then the resist layer was visually observed. Blistering/peeling The swelling and peeling of the resist were visually confirmed. The obtained results are shown in Table 2 below.
◯: No swelling or peeling △: Slight swelling or peeling occurred ×: Swelling or peeling occurred

Claims (5)

(A ) ( a) A reaction product of a novolac type epoxy compound and (b) an unsaturated monocarboxylic acid, (c) a reaction product of a saturated or unsaturated polybasic acid anhydride, and an unreacted (c) saturated product . or unsaturated polybasic acid anhydride, (d) and a reaction product of a hydroxyl group-containing monomer, prior Symbol unreacted (c) does not include a saturated or unsaturated polybasic acid anhydride, active energy solventless Wire curable resin varnish,
A photocurable thermosetting resin composition comprising (B) a photopolymerization initiator, or a mixture of a photopolymerization initiator and a sensitizer, and (C) a thermosetting component. The photocurable thermosetting resin composition according to claim 1, wherein the sensitizer as the component (B) contains at least one selected from thioxanthone compounds and amine compounds. The photocurable thermosetting resin composition according to claim 1, wherein the thermosetting component (C) is a compound having a cyclic (thio)ether group. A cured product obtained by subjecting the photocurable thermosetting resin composition according to claim 1 to photocuring and then heat curing. A printed wiring board having a coating film made of the cured product according to claim 4.