JP5739609B2 - Photosensitive resin composition, solder resist composition and printed wiring board - Google Patents

Description

  This invention was formed from the photosensitive resin composition used suitably for formation of the soldering resist layer of a printed wiring board, the composition for soldering resist containing this photosensitive resin composition, and this composition for soldering resist The present invention relates to a printed wiring board provided with a solder resist layer.

  In recent years, as a resist pattern forming method for various printed circuit boards for consumer use and industrial use, it has excellent resolution and dimensional accuracy in place of the screen printing method in order to cope with the higher wiring density of printed wiring boards. A method using a dry film or a liquid developable photosensitive resin composition has occupied a large position.

  In recent years, optical elements such as light emitting diodes used in backlights for liquid crystal displays such as portable terminals, personal computers, and televisions, and light sources for lighting fixtures have been directly mounted on printed wiring boards coated with a solder resist layer. Things to do are increasing.

  In a printed wiring board on which such an optical element is mounted, there is a problem that the solder resist layer is deteriorated by light and discoloration occurs. In particular, when the light is emitted from the light emitting diode or the like in order to efficiently reflect the light in the solder resist layer, the solder resist layer is whitened by containing titanium oxide in the solder resist layer. There is a problem that yellowing easily occurs and the light reflection performance of the solder resist layer is lowered.

  Therefore, Patent Document 1 proposes to suppress yellowing of the solder resist layer by forming a solder resist layer using a carboxyl group-containing resin having no aromatic ring as a matrix resin.

  However, if the matrix resin is limited to a resin that does not have an aromatic ring as described above, the selection range of the matrix resin is narrowed, and the acid resistance, alkali resistance, and developability required for the solder resist layer are reduced. In some cases, it may be difficult to sufficiently exhibit performance such as adhesion to the substrate, plating resistance, solder heat resistance, and electric corrosion resistance.

JP 2007-322546 A

  The present invention has been made in view of the above points, and is suitably used for forming a solder resist layer. While using a resin prepared from an aromatic ring-containing epoxy resin as a matrix resin, deterioration of a cured film by light A photosensitive resin composition capable of suppressing the above, a solder resist composition comprising the photosensitive resin, and a printed wiring board having a cured film formed from the solder resist composition as a solder resist layer With the goal.

The photosensitive resin composition according to the present invention, characterized by containing the following components A1, B1, C and D, the aromatic ring-containing epoxy resin in the following components A1 is, containing cresol novolac type epoxy resin or a naphthalene type epoxy resin And

A1 a photosensitive resin obtained from a hydrogenated epoxy resin obtained by hydrogenating an aromatic ring-containing epoxy resin and having at least two ethylenically unsaturated groups in one molecule
B1 an epoxy compound having at least two epoxy groups in one molecule,
C photopolymerization initiator,
D Diluent.

  The “aromatic ring” refers to an aromatic ring composed of a hydrocarbon, and does not include, for example, a heterocyclic ring.

  For this reason, while using a resin prepared from an aromatic ring-containing epoxy resin as a matrix resin, hydrogenation of this aromatic ring-containing epoxy resin suppresses deterioration of the cured product of the photosensitive resin composition due to light, so Yellowing of the cured film formed from the conductive resin composition can be suppressed.

  In the present invention, the hydrogenation rate of the aromatic ring of the hydrogenated epoxy resin in Component A1 is preferably 50% or more.

  In this case, deterioration of the cured product of the photosensitive resin composition by light can be sufficiently suppressed, and yellowing of the cured film formed from the photosensitive resin composition can be further suppressed.

When the aromatic ring-containing epoxy resin in Component A1 contains a cresol novolac type epoxy resin or a naphthalene type epoxy resin , the acid resistance of the cured film is suppressed while suppressing deterioration of the cured film formed from the photosensitive resin composition, Alkali resistance, developability, adhesion to the substrate, plating resistance, and solder heat resistance can be improved.

  Moreover, it is preferable that the photosensitive resin composition contains the following component E further.

E White colorant In this case, the color of the cured film formed from the photosensitive resin composition can be made white, which is particularly suitable for forming a highly reflective solder resist layer.

  The composition for solder resists according to the present invention is characterized by comprising the above photosensitive resin composition.

  Therefore, the solder resist composition can be prepared from the aromatic ring-containing epoxy resin, and the light of the solder resist layer formed from the solder resist composition by hydrogenating the aromatic ring-containing epoxy resin. It is possible to suppress deterioration due to, and to suppress yellowing of the solder resist layer.

  The printed wiring board which concerns on this invention is equipped with the permanent film formed from the said composition for soldering resists, It is characterized by the above-mentioned.

  Therefore, a solder resist composition can be prepared from an aromatic ring-containing epoxy resin, and the hydrogen of the aromatic ring-containing epoxy resin can be used to light the solder resist layer formed from the solder resist composition. Deterioration can be suppressed and yellowing of the solder resist layer can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, deterioration by the light of the cured film formed from this photosensitive resin composition can be suppressed, using what was prepared from the aromatic ring containing epoxy resin as matrix resin.

  By forming a solder resist layer of a printed wiring board with a solder resist composition comprising this photosensitive resin composition, the solder resist layer is deteriorated by light without limiting the matrix resin to a resin having no aromatic ring. Can be suppressed.

  Embodiments of the present invention will be described below.

  The photosensitive resin composition according to the present invention contains the following photosensitive resin A1, epoxy compound B1, photopolymerization initiator C, and diluent D. Alternatively, the photosensitive resin composition according to the present invention comprises at least one of the following photosensitive resin A1 and photosensitive resin A2, hydrogenated epoxy compound B2, photopolymerization initiator C, and diluent D. contains. In particular, the photosensitive resin composition preferably contains a photosensitive resin A1, a hydrogenated epoxy compound B2, a photopolymerization initiator C, and a diluent D. The photosensitive resin A1, the photosensitive resin A2, the epoxy compound B1, and the hydrogenated epoxy compound B2 serve as a matrix resin when a cured product is formed from the photosensitive resin composition. Hereinafter, each component will be described in detail.

[Photosensitive resin A1]
The photosensitive resin A1 is synthesized from a hydrogenated epoxy resin a1 obtained by hydrogenating an aromatic ring-containing epoxy resin, and has at least two ethylenically unsaturated groups in one molecule. This photosensitive resin A1 is obtained by adding an ethylenically unsaturated compound b having a carboxyl group to a hydrogenated epoxy resin a1 obtained by hydrogenating an aromatic ring-containing epoxy resin having at least two epoxy groups in one molecule. It can be synthesized by reacting with a saturated or unsaturated acid anhydride c. In this case, photosensitive resin A1 will have a carboxyl group, and can provide the photosensitive resin composition with peelability by an alkaline solution.

  Although this photosensitive resin A1 is prepared from an aromatic ring-containing epoxy resin, since the aromatic ring is hydrogenated, a cured product of the photosensitive resin composition containing this photosensitive resin A1 as a matrix resin. Deterioration of is suppressed.

  The hydrogenated epoxy resin a1 is particularly preferably a novolak type epoxy resin that has been hydrogenated. The novolac type epoxy resin can be obtained by reacting various phenol novolac resins obtained by reacting various phenols with formaldehyde in the presence of a basic catalyst with epihalohydrin. Examples of phenols include phenol, cresol, resorcin, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, bisphenol AD, biphenol compounds, dihydroxynaphthalene, and the like. Particularly preferred novolak type epoxy resins include phenol novolak type epoxy resins, cresol novolak type epoxy resins, and bisphenol A-novolak type epoxy resins.

  Alternatively, the hydrogenated epoxy resin a1 can be obtained by hydrogenating a polycyclic aromatic epoxy resin other than the novolac epoxy resin. Examples of the polycyclic aromatic type epoxy resin include naphthalene type epoxy resin and biphenyl type epoxy resin.

  The hydrogenation of the epoxy resin can be performed, for example, by hydrogenating the epoxy resin with hydrogen under pressure in the presence of a hydrogenation catalyst such as ruthenium or rhodium.

  As the ethylenically unsaturated compound b having a carboxyl group, an appropriate polymer or prepolymer is used. For example, acrylic acid, 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-carboxy Ethoxy) -3-oxypropyl ester, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2- Such as Tak Leroy oxyethyl hexahydrophthalic acid, a compound having only one ethylenically unsaturated group. The ethylenically unsaturated compound b has a hydroxyl group such as pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate and the like. A compound having a plurality of ethylenically unsaturated groups such as those obtained by reacting a polyfunctional acrylate or polyfunctional methacrylate with a dibasic acid anhydride can also be used. These compounds can be used alone or in combination of two or more. In addition, since the ethylenically unsaturated group introduced into the photosensitive resin composition by acrylic acid and methacrylic acid is particularly excellent in photoreactivity, the ethylenically unsaturated compound b having a carboxyl group is selected from acrylic acid and methacrylic acid. It is preferable to contain at least one.

  The amount of the ethylenically unsaturated compound b used is such that the carboxyl group of the ethylenically unsaturated compound b is in the range of 0.7 to 1.2 mol with respect to 1 mol of the epoxy group of the hydrogenated epoxy resin a1. It is particularly preferable that the amount of the carboxyl group be in the range of 0.9 to 1.1 mol. In this case, the residual amount of epoxy groups in the photosensitive resin A1 is particularly reduced, and the photosensitive resin A1 undergoes a thermosetting reaction when the photosensitive resin composition is subjected to weak heat drying conditions such as preliminary drying. Occurrence can be suppressed, and deterioration of developability after exposure of the photosensitive resin composition can be prevented. Moreover, it can also suppress that the ethylenically unsaturated compound b which has an unreacted carboxyl group remains in the photosensitive resin composition.

  Examples of the saturated or unsaturated acid anhydride c include, for example, succinic anhydride, methyl succinic anhydride, maleic anhydride, citraconic anhydride, glutaric anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydroanhydride. Dibasic acid anhydrides such as phthalic acid, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride And acid anhydrides of tribasic acids or higher. These compounds can be used alone or in combination of two or more.

  The acid anhydride c is used mainly for the purpose of giving an acid value to the photosensitive resin A1 and imparting re-dispersion and re-solubility to the photosensitive resin composition with a dilute aqueous alkali solution. The amount of the acid anhydride c used is preferably selected so that the acid value of the photosensitive resin A1 is in the range of 25 to 150 mgKOH / g. If the acid value of the photosensitive resin A1 is 25 mgKOH / g or more, good developability can be imparted to the photosensitive resin composition, and if it is 150 mgKOH / g or less, the photosensitive resin A1 is formed from the photosensitive resin A1. Residual carboxyl groups in the cured film can be reduced, and good electrical characteristics, corrosion resistance, water resistance, and the like of the cured film can be maintained. In particular, the optimum effect can be obtained when the acid value of the photosensitive resin A1 is 40 to 100 mgKOH / g.

  The addition reaction of the hydrogenated epoxy resin a1 with the ethylenically unsaturated compound b having a carboxyl group and the saturated or unsaturated acid anhydride c can be performed by a known method. For example, in the addition reaction between the hydrogenated epoxy resin a1 and the ethylenically unsaturated compound b having a carboxyl group, the ethylenically unsaturated compound b having a carboxyl group is added to the solvent solution of the hydrogenated epoxy resin a1, and further if necessary. Then, a thermal polymerization inhibitor and a catalyst are added and stirred and mixed, and the reaction is carried out by a conventional method, preferably at a reaction temperature of 60 to 150 ° C., particularly preferably 80 to 120 ° C. Examples of the thermal polymerization inhibitor include hydroquinone or hydroquinone monomethyl ether. Examples of the catalyst include tertiary amines such as benzyldimethylamine and triethylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride and methyltriethylammonium chloride, and triphenylstibine.

  In addition, in the addition reaction between the hydrogenated epoxy resin a1 and the ethylenically unsaturated compound b having a carboxyl group and the saturated or unsaturated polybasic acid anhydride c, a solvent solution of the addition reaction product is used. Saturated or unsaturated polybasic acid anhydride c is added to the mixture, and if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed by stirring, followed by a conventional method. The reaction conditions can be the same as in the addition reaction between the hydrogenated epoxy resin a1 and the ethylenically unsaturated compound b. The thermal polymerization inhibitor and the catalyst are the hydrogenated epoxy resin a1 and the ethylenically unsaturated compound b. Those used in the addition reaction with can be used as they are.

  The weight average molecular weight of the photosensitive resin A1 is not particularly limited, but a preferable range is 3000 to 400,000. In this range, particularly excellent sensitivity and resolution are imparted to the photosensitive resin composition.

  The blending amount of the photosensitive resin A1 in the photosensitive resin composition is not particularly limited, but is 10 to 80% by mass in the total amount of the components of the photosensitive resin composition excluding the organic solvent in the diluent D blended at the same time. A range is desirable. In this case, it is possible to sufficiently ensure good sensitivity and work characteristics of the photosensitive resin composition and good physical properties of the cured film.

[Photosensitive resin A2]
Photosensitive resin A2 is synthesized from epoxy compound a2 having no aromatic ring, and has at least two ethylenically unsaturated groups in one molecule.

  Since this photosensitive resin A2 is prepared from the epoxy compound a2 having no aromatic ring, deterioration of the cured product of the photosensitive resin composition containing this photosensitive resin A2 as a matrix resin is suppressed.

  Examples of the photosensitive resin A2 include the following photosensitive resins A21, A22, and A23.

  Polymer obtained by using ethylenically unsaturated compound a21 having an epoxy group as epoxy compound a2 and polymerizing this ethylenically unsaturated compound a21 and other ethylenically unsaturated compound d used as necessary A photosensitive resin A21 obtained by reacting an ethylenically unsaturated compound b having a carboxyl group with a saturated or unsaturated acid anhydride c.

  An epoxy compound a22 having two or more epoxy groups in one molecule is used as the epoxy compound a2, and the epoxy compound a22 is reacted with an ethylenically unsaturated compound b having a carboxyl group and a saturated or unsaturated acid anhydride c. A photosensitive resin A22 obtained by heating.

  A compound obtained by polymerizing an ethylenically unsaturated compound b having a carboxyl group and another ethylenically unsaturated compound d used as necessary, using an ethylenically unsaturated compound a21 having an epoxy group, Photosensitive resin A23 obtained by reacting the ethylenically unsaturated compound a21 having the epoxy group.

  As the ethylenically unsaturated compound a21 having an epoxy group, a suitable polymer or prepolymer having no aromatic ring is used. For example, epoxycyclohexyl derivatives of acrylic acid or methacrylic acid; alicyclic epoxy derivatives of acrylate or methacrylate ; Β-methyl glycidyl acrylate, β-methyl glycidyl methacrylate and the like. These compounds can be used alone or in combination of two or more. In particular, it is preferable to use glycidyl (meth) acrylate which is widely used and easily available.

  As the epoxy compound a22 having two or more epoxy groups in one molecule, an appropriate epoxy resin having no aromatic ring, a polymerized epoxy compound, or the like can be used alone or in combination. In particular, triglycidyl isocyanurate, alicyclic epoxy resin fat, and the like are preferable, and these epoxy compounds can be used alone or in combination of two or more.

  The ethylenically unsaturated compound b having a carboxyl group and the saturated or unsaturated acid anhydride c are the same as the ethylenically unsaturated compound b and acid anhydride c used in the preparation of the photosensitive resin A1. Can be used.

  As the ethylenically unsaturated compound d, an appropriate polymer or prepolymer is used. In the photosensitive resin A21, ethylene that can be copolymerized with the ethylenically unsaturated compound a21 and A23 with the ethylenically unsaturated compound b, respectively. Any unsaturated unsaturated monomer may be used. The ethylenically unsaturated compound d is used as necessary for adjusting the photocurability of the photosensitive resin and adjusting the physical properties of the cured film. Examples of the ethylenically unsaturated compound d include linear or branched aliphatic, aromatic, or alicyclic (however, the ring may have a partially unsaturated bond) acrylic ester or methacrylic ester. Examples include acid esters, hydroxyalkyl acrylates or hydroxyalkyl methacrylates, alkoxyalkyl acrylates or alkoxyalkyl methacrylates, benzyl acrylates or benzyl methacrylates, N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, and styrene. In addition to these, if necessary, one molecule such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, etc. A compound having two or more ethylenically unsaturated groups can also be used. These can be used alone or in combination of two or more. These ethylenically unsaturated compounds d are particularly suitable in that the hardness and oiliness of the cured film can be easily adjusted.

  In the production of the photosensitive resin A21, the amount of the ethylenically unsaturated compound a21 having an epoxy group is preferably in the range of 40 to 95 mol% in the total amount of the polymerizable compound components used in the production of the copolymer. . When this is 40 mol% or more, sufficient photocurability is obtained, good sensitivity and resolution are obtained in the pattern formation process, and solder heat resistance of the finally formed solder resist is further improved. can do. A particularly preferable range is 50 to 95 mol%, and in this range, the formed solder resist exhibits particularly excellent solder heat resistance and electric corrosion resistance.

  In the production of the photosensitive resin A21, the reaction between the ethylenically unsaturated compound a21 and the ethylenically unsaturated compound d is performed by a known polymerization method such as solution polymerization or emulsion polymerization. As a solution polymerization method, a mixture of the ethylenically unsaturated compound a21 and the ethylenically unsaturated compound d is heated in a suitable organic solvent in a nitrogen atmosphere in the presence of a polymerization initiator. Examples thereof include a stirring method and an azeotropic polymerization method.

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

  Examples of the polymerization initiator for the polymerization include hydroperoxides such as diisopropylbenzene hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane. Such as dialkyl peroxides such as isobutyryl peroxide, ketone peroxides such as methyl ethyl ketone peroxide, alkyl peresters such as t-butyl peroxybivalate, perisopropyl such as diisopropyl peroxydicarbonate Examples include azo compounds such as oxydicarbonates and azobisisobutyronitrile. These can be used alone or in combination of two or more. A redox initiator may be used as the polymerization initiator.

  Further, in the production of the photosensitive resin A21 and the photosensitive resin A22, the amount of the ethylenically unsaturated compound b having a carboxyl group is used per 1 mol of the epoxy group of the copolymer in the production of the photosensitive resin A21. Alternatively, the amount is preferably such that the carboxyl group of the ethylenically unsaturated compound b is in the range of 0.7 to 1.2 mol per mol of the epoxy group of the epoxy compound a22 in the production of the photosensitive resin A22. The amount is preferably such that the carboxyl group is in the range of 0.9 to 1.1 mol. In this case, the residual amount of epoxy groups in the photosensitive resin is particularly reduced, and the photosensitive resin undergoes a thermosetting reaction when the photosensitive resin composition is subjected to weak thermal drying conditions such as preliminary drying. Can be suppressed, and a decrease in developability after exposure of the photosensitive resin composition can be prevented. Moreover, it can also suppress that the ethylenically unsaturated compound b which has an unreacted carboxyl group remains in the photosensitive resin composition.

  In the production of the photosensitive resin A21 and the photosensitive resin A22, the acid anhydride c mainly imparts an acid value to the photosensitive resin and imparts re-dispersion and re-solubility to the photosensitive resin composition with a dilute aqueous alkali solution. Used as a purpose. The amount of acid anhydride c used is preferably selected so that the acid value of the photosensitive resin is in the range of 25 to 150 mgKOH / g. If the acid value of this photosensitive resin is 25 mgKOH / g or more, good developability can be imparted to the photosensitive resin composition, and if it is 150 mgKOH / g or less, a cured film formed from the photosensitive resin. Residual carboxyl groups can be reduced, and good electrical properties, corrosion resistance, water resistance, etc. of the cured film can be maintained. In particular, when the acid value of the photosensitive resin is 40 to 100 mgKOH / g, the optimum effect is obtained.

  In the production of the photosensitive resin A21 and the photosensitive resin A22, the addition reaction of the ethylenically unsaturated compound b having a carboxyl group and the saturated or unsaturated acid anhydride c can be performed using a known method. Specifically, it is carried out by the same method as the addition reaction between the hydrogenated epoxy resin a1 during the production of the photosensitive resin A1, the ethylenically unsaturated compound b having a carboxyl group and the saturated or unsaturated acid anhydride c. be able to.

  In the production of A23, a copolymer obtained by reacting the ethylenically unsaturated compound b and the ethylenically unsaturated compound d is obtained by a known polymerization method, for example, the same method as used for the production of A21. be able to. In addition, a known method can be used for the reaction of adding an ethylenically unsaturated compound a21 having an epoxy group to the copolymer. For example, the ethylenically unsaturated compound in the production of the photosensitive resin A21 and the photosensitive resin A22 can be used. A method similar to the addition reaction of b or acid anhydride c can be employed. In the production of the photosensitive resin A23, the amount of the ethylenically unsaturated compound a21 having an epoxy group is such that the carboxyl group remains in the produced photosensitive resin A23 and the photosensitive resin A23 has a sufficient acid value. It is preferable that it is the quantity which comes to have.

[Epoxy compound B1]
The epoxy compound B1 has at least two epoxy groups in one molecule. The epoxy compound B1 may be a solvent-poorly soluble epoxy compound or a general-purpose solvent-soluble epoxy compound. The type of the epoxy compound B is not particularly limited, but triglycidyl isocyanurate, YX4000 (manufactured by Japan Epoxy Resin Co., Ltd.), phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A type epoxy resin and bisphenol A novolak type. Epoxy resin is desirable. Of these, when triglycidyl isocyanurate is used, this triglycidyl isocyanurate is a β-form having a structure in which three epoxy groups are bonded in the same direction to the S-triazine ring skeleton, or the β-form. And an α-isomer having a structure in which one epoxy group is bonded to the S-triazine ring skeleton surface in a different direction from the other two epoxy groups.

  When this epoxy compound B1 does not have an aromatic ring, deterioration of the cured product of the photosensitive resin composition containing this epoxy compound B1 as a matrix resin is further suppressed.

  The blending amount of the epoxy compound B1 in the photosensitive resin composition is not particularly limited, but is 0.1% by mass or more in the total amount of the components of the photosensitive resin composition excluding the organic solvent in the diluent D blended at the same time. In this case, it is possible to further improve the solder resistance, plating resistance, etc. of the cured film. Moreover, the developability of the photosensitive resin composition can be further improved by adjusting the blending amount to 50% by weight or less.

[Hydrogenated epoxy compound B2]
The hydrogenated epoxy compound B2 is obtained by hydrogenating an aromatic ring-containing epoxy resin, and has at least two epoxy groups in one molecule. As this hydrogenated epoxy compound B2, the same one as the hydrogenated epoxy resin a1 used for the preparation of the photosensitive resin A1 can be used.

  The hydrogenated epoxy compound B2 is particularly preferably a novolak type epoxy resin that is hydrogenated. Further, the hydrogenated epoxy compound B2 can also be obtained by hydrogenating a polycyclic aromatic epoxy resin other than the novolac epoxy resin.

  This hydrogenated epoxy compound B2 is prepared from an aromatic ring-containing epoxy resin, but since the aromatic ring is hydrogenated, a photosensitive resin composition containing this hydrogenated epoxy compound B2 as a matrix resin is used. Deterioration of the cured product will be suppressed.

  The blending amount of the hydrogenated epoxy compound B2 in the photosensitive resin composition is not particularly limited, but is 0.1% by mass in the total amount of the components of the photosensitive resin composition excluding the organic solvent in the diluent D blended at the same time. The above is preferable, and in this case, the solder resistance and plating resistance of the cured film can be further improved. Moreover, the developability of the photosensitive resin composition can be further improved by adjusting the blending amount to 50% by weight or less.

[Photopolymerization initiator C]
Examples of the photopolymerization initiator C include benzoin and its alkyl ethers, acetophenones such as acetophenone and benzyldimethyl ketal, anthraquinones such as 2-methylanthraquinone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, Thioxanthones such as 2-isopropylthioxanthone, 4-isopropylthioxanthone and 2,4-diisopropylthioxanthone; benzophenones such as benzophenone and 4-benzoyl-4′-methyldiphenyl sulfide; and xanthones such as 2,4-diisopropylxanthone; Α-hydroxy ketones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, etc. Those containing nitrogen atom, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, and the like. Along with these photopolymerization initiators C, known photopolymerization accelerators and sensitizers such as tertiary amines such as p-dimethylbenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, 2-dimethylaminoethylbenzoate, etc. An agent or the like may be used in combination. Photopolymerization initiators for exposure to visible light, near infrared light, etc. can also be used. These photopolymerization initiators C can be used alone or in combination of two or more. Moreover, coumarin derivatives such as 7-diethylamino-4-methylcoumarin, other carbocyanine dyes, xanthene dyes, and the like can be used in combination as sensitizers for laser exposure.

  The blending amount of the photopolymerization initiator C in the photosensitive resin composition can achieve a good balance between the photocurability of the photosensitive resin composition and the physical properties of the cured film formed from the photosensitive resin composition. It is preferable to set it appropriately so that it is preferably in the range of 0.1 to 30% by mass in the total amount of the components of the photosensitive resin composition excluding the organic solvent in the diluent D blended at the same time.

[Diluent D]
As the diluent D, at least one of a photopolymerizable compound and an organic solvent can be used.

  The photopolymerizable compound is prepared by diluting the photosensitive resin composition so that it can be easily applied, adjusting the acid value of the entire photosensitive resin composition, or improving the photopolymerizability of the photosensitive resin composition. Can be used to An appropriate polymer or prepolymer can be used as the photopolymerizable compound. Specific examples of the photopolymerizable compound include monofunctional acrylates such as 2-hydroxyethyl acrylate; diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri ( Examples thereof include polyfunctional (meth) acrylates such as (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. Such photopolymerizable compounds can be used alone or in combination of two or more.

  When using a photopolymerizable compound, it is preferable that content of the photopolymerizable compound in the photosensitive resin composition is 0.05-40 mass%. In addition, the blending amount is desirably 50% by weight or less in the total amount of the photosensitive resin composition excluding the organic solvent, thereby suppressing the surface adhesiveness of the dry film from becoming too strong. When the negative mask on which the pattern is drawn is directly applied to the surface of the dried coating film for exposure, the negative mask can be prevented from being stained.

  The organic solvent should be used to dissolve the photosensitive resin A, etc., dilute the photosensitive resin composition and make it coatable as a liquid, or improve the film-forming property by drying the photosensitive resin composition. Can do. Specific examples of the organic solvent include linear, branched, secondary or polyhydric alcohols such as ethanol, propyl alcohol, isopropyl alcohol, hexanol and ethylene glycol; ketones such as methyl ethyl ketone and cyclohexanone; aroma such as toluene and xylene. Group hydrocarbons; petroleum-based aromatic mixed solvents such as Swazol series (manufactured by Maruzen Petrochemical Co., Ltd.) and Solvesso series (manufactured by Exxon Chemical Co.); cellosolves such as cellosolve and butylcellosolve; carbitol, butylcarbitol Carbitols such as; propylene glycol alkyl ethers such as propylene glycol methyl ether; polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether; ethyl acetate, butyl acetate, cellosolve acetate Acetic esters; dialkyl glycol ethers and the like. These organic solvents can be used alone or in combination of two or more.

  It is preferable that the content of the organic solvent is appropriately selected so that it is volatilized quickly during temporary drying and does not remain in the dry film. This content is particularly preferably in the range of 5 to 99.5% by weight in the total amount of the components of the composition, and in this case, good coatability of the photosensitive resin composition can be maintained. In addition, since the suitable compounding quantity of an organic solvent changes with application methods, it is preferable to adjust suitably according to the application method.

[White colorant E]
The photosensitive resin composition may be colored white by containing the white colorant E. In this case, the color of the cured film formed from the photosensitive resin composition can be made white, which is particularly suitable for forming a highly reflective solder resist layer. Examples of the white colorant E include titanium oxide, barium sulfate, and magnesium oxide.

  Although the usage-amount of the white coloring agent E is set suitably, Preferably it is the range of 5-80 mass%, More preferably, you may be the range of 15-50 mass%. When the amount used is 5% by mass or more, the cured film formed from the photosensitive resin composition can exhibit high concealability and whiteness, and the amount used is 80% by mass or less. By doing so, the physical properties required for the resist such as the heat resistance and pencil hardness of the cured film can be maintained high.

[Other ingredients]
In the photosensitive resin composition, in addition to the above components, for example, tolylene diisocyanate blocked with caprolactam, oxime, malonate, etc., morpholine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate blocked isocyanate, and melamine Thermosetting components such as amino resins such as n-butylated melamine resin, isobutylated melamine resin, butylated urea resin, butylated melamine urea cocondensation resin, benzoguanamine-based cocondensation resin; UV curable epoxy (meth) acrylate; Bisphenol A type, phenol novolac type, cresol novolak type, alicyclic epoxy resin, etc. with (meth) acrylic acid added; diallyl phthalate resin, phenoxy resin, melamine resin, urethane resin, fluorine resin And polymeric compounds such as may be added as appropriate.

  Moreover, you may mix | blend photosensitive resin other than the said photosensitive resin A1, A2 in the photosensitive resin composition in the range which is not contrary to the objective of this invention.

  Further, for the photosensitive resin composition, if necessary, adhesion of epoxy resin curing agent; curing accelerator; colorant other than white; copolymer such as silicone and acrylate; leveling agent; silane coupling agent, etc. An agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; an antioxidant surfactant;

[Preparation of photosensitive resin composition]
The above photosensitive resin A1, epoxy compound B1, photopolymerization initiator C and diluent D are blended, or at least one of photosensitive resin A1 and photosensitive resin A2, hydrogenated epoxy compound B2, photopolymerization initiator. A photosensitive resin composition is obtained by blending C and diluent D, further blending other components as necessary, and kneading by a known kneading method using, for example, a three-roll, ball mill, sand mill or the like. be able to. In that case, a part of each of the above components, for example, a part of the D component and the B1, B2 components are mixed and dispersed in advance, and separately the remaining components are mixed and dispersed in advance. The photosensitive resin composition may be prepared by mixing both at the time of use.

[Formation of solder resist layer on printed wiring board]
Using the photosensitive resin composition as a solder resist composition, a solder resist layer can be formed on a printed wiring board, and a printed wiring board having a solder resist layer can be produced. The method for forming the solder resist layer is not particularly limited, but the most general method is exemplified as follows.

  After applying the solder resist composition to the printed wiring board by an appropriate method such as dipping, spraying, spin coating, roll coating, curtain coating, screen printing, etc., the organic solvent in the solder resist composition is volatilized. For example, preliminary drying is performed at 60 to 120 ° C. to form a dry film.

  A negative mask on which a pattern is drawn is applied directly or indirectly to the surface of the dry film and irradiated with active energy rays, whereby the dry film is exposed through the negative mask. As a negative mask, a photo tool such as a mask film or a dry plate in which the pattern shape of the solder resist layer is drawn as an exposed portion that transmits active energy rays and other portions are formed as non-exposed portions that shield active energy rays Etc. are used. Examples of the active energy rays include appropriate active energy rays such as ultraviolet rays, visible light, and near infrared rays depending on the composition of the solder resist composition. For example, ultraviolet rays are irradiated from a light source such as a chemical lamp, 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.

  The exposure method is not limited to the method using a negative mask as described above, and an appropriate method can be employed. For example, a direct drawing method using laser exposure or the like can be employed.

  The negative mask is removed from the printed wiring board after exposure and developed to remove the non-exposed portion of the dry film, and a solder resist layer is formed on the exposed portion of the remaining dry film.

  In the development process, an appropriate developer according to the type of the solder resist composition forming the photosensitive resin layer can be used. Specific examples of the developer include, for example, sodium carbonate aqueous solution, potassium carbonate aqueous solution, ammonium carbonate aqueous solution, sodium hydrogen carbonate aqueous solution, potassium hydrogen carbonate aqueous solution, ammonium hydrogen carbonate aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonium hydroxide aqueous solution, An alkaline solution such as a lithium hydroxide aqueous solution can be exemplified. In addition to the alkaline solution, organic amines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine can be used, and these can be used alone or in combination. it can. As the solvent of the alkaline solution, not only water alone but also a mixture of water and a hydrophilic organic solvent such as lower alcohols can be used.

  Furthermore, if necessary, the solder resist layer is heat-treated at 120 to 180 ° C. for about 30 to 90 minutes to thermally cure the epoxy compounds B1 and B2, and the film strength, hardness, and resistance of the solder resist layer are cured. Improve chemical properties.

  Hereinafter, the present invention will be described in more detail by presenting specific examples of the present invention.

[Synthesis Example 1]
In 200 parts of carbitol acetate, 265 parts of a hydrogenated cresol novolac type epoxy resin (nuclear hydrogenation rate 95%, epoxy equivalent 265) are dissolved, and while stirring this, 74 parts of acrylic acid, 0.1 part of hydroquinone and dimethylbenzyl are added. 0.7 parts of amine was added and reacted at 90-100 ° C. for 24 hours by a conventional method.

  To the solution thus obtained, 76 parts of tetrahydrophthalic anhydride and 215 parts of carbitol acetate were added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (A-1) of a photosensitive resin.

[Synthesis Example 2]
Add 200 parts of hydrogenated cresol novolac type epoxy resin (nuclear hydrogenation rate 88%, epoxy equivalent 230) to 200 parts of carbitol acetate and dissolve it, stirring 74 parts of acrylic acid, 0.1 part of hydroquinone and dimethyl 0.7 part of benzylamine was added and reacted at 90-100 ° C. for 24 hours by a conventional method.

  To the solution thus obtained, 76 parts of tetrahydrophthalic anhydride and 180 parts of carbitol acetate were added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (A-2) of a photosensitive resin.

[Synthesis Example 3]
In 200 parts of carbitol acetate, 206 parts of hydrogenated cresol novolac type epoxy resin (nuclear hydrogenation rate 76%, epoxy equivalent 206) is added and dissolved, and 74 parts of acrylic acid, 0.1 part of hydroquinone and dimethyl are stirred with stirring. 0.7 part of benzylamine was added and reacted at 90-100 ° C. for 24 hours by a conventional method.

  To the solution thus obtained, 76 parts of tetrahydrophthalic anhydride and 156 parts of carbitol acetate were added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (A-3) of a photosensitive resin.

[Synthesis Example 4]
To 200 parts of carbitol acetate, 215 parts of hydrogenated naphthalene type epoxy resin (nuclear hydrogenation rate 90%, epoxy equivalent 215) was added and dissolved. While stirring this, 74 parts of acrylic acid, 0.1 part of hydroquinone and dimethyl were added. 0.7 part of benzylamine was added and reacted at 90-100 ° C. for 24 hours by a conventional method.

  To the solution thus obtained, 76 parts of tetrahydrophthalic anhydride and 165 parts of carbitol acetate were added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (A-4) of a photosensitive resin.

[Synthesis Example 5]
To 200 parts of carbitol acetate, 230 parts of hydrogenated bisphenol A type epoxy resin (epoxy equivalent 230, manufactured by Tohto Kasei Co., Ltd., product number ST-3000) was added and dissolved, and 74 parts of acrylic acid, 0. 1 part and 0.7 part of dimethylbenzylamine were added, and it was made to react at 90-100 degreeC by a conventional method for 24 hours.

  To the solution thus obtained, 76 parts of tetrahydrophthalic anhydride and 180 parts of carbitol acetate were added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (A-5) of a photosensitive resin.

[Synthesis Example 6]
A four-necked flask equipped with a reflux condenser, a thermometer, a glass tube for nitrogen substitution, and a stirrer, 30 parts of methacrylic acid, 50 parts of methyl methacrylate, 20 parts of butyl methacrylate, 100 parts of carbitol acetate, 0.5 parts of lauryl mercaptan And 4 parts of azobisisobutyronitrile were added, heated under a nitrogen stream, and polymerized at 75 ° C. for 5 hours to obtain a 50% copolymer solution.

  To this 50% copolymer solution, 0.05 part of hydroquinone, 28.4 parts of glycidyl methacrylate and 2.0 parts of dimethylbenzylamine were added and subjected to an addition reaction at 80 ° C. for 24 hours, and then 13 parts of carbitol acetate was added. By adding, the 50% solution (A-6) of photosensitive resin was obtained.

[Synthesis Example 7]
In a four-necked flask equipped with a thermometer, a nitrogen replacement glass tube and a stirrer in a reflux condenser, 70 parts of glycidyl methacrylate, 30 parts of methyl methacrylate, 100 parts of carbitol acetate, 0.2 part of lauryl mercaptan, azobisiso 3 parts of butyronitrile was added and polymerization was carried out at 80 ° C. for 5 hours while heating and stirring under a nitrogen stream to obtain a 50% copolymer solution.

  To this 50% copolymer solution, 0.05 part of hydroquinone, 37 parts of acrylic acid and 0.2 part of dimethylbenzylamine were added, followed by addition reaction at 100 ° C. for 24 hours, followed by 45 parts of tetrahydrophthalic anhydride. 79 parts of carbitol acetate was added and reacted at 100 ° C. for 3 hours to obtain a 50% solution (B-1) of a photosensitive resin.

[Synthesis Example 8]
To 60 parts of carbitol acetate, 214 parts of Epicron N-680 (Cresol novolak type resin, epoxy equivalent 214, manufactured by Dainippon Ink and Chemicals, Inc.) were added and dissolved, and 74 parts of acrylic acid, 0. 1 part and 0.7 part of dimethylbenzylamine were added, and it was made to react at 90-100 degreeC by a conventional method for 24 hours.

  95 parts of carbitol acetate was added to the resulting solution and stirred to obtain an epoxy acrylate solution.

  Subsequently, 76 parts of tetrahydrophthalic anhydride and 87 parts of carbitol acetate were added to this solution and reacted at 100 ° C. for 3 hours to obtain a 50% solution (B-2) of a photosensitive resin.

[Examples 1 to 10 and Comparative Examples 1 to 3]
The ingredients of each composition shown in Table 1 were added to the photosensitive resin solution produced in each of the above synthesis examples, and this was kneaded with three rolls. Photosensitivity of Examples 1 to 10 and Comparative Examples 1 to 4 A functional resin composition was obtained.

  “Lucirin TPO” in Table 1 is diphenyl (2,4,6-trimethoxybenzoyl) phosphine oxide as a photopolymerization initiator, “DPHA” is dipentaerythritol hexaacrylate, and “silicone” is Shin-Etsu Silicone Co., Ltd. Each manufactured product number KS-66 is shown.

  “C-1” in Table 1 is a 70% carbitol acetate solution of hydrogenated cresol novolak epoxy resin (nuclear hydrogenation rate 95%, epoxy equivalent 265), and “C-2” is hydrogenated bisphenol A. 70% carbitol acetate solution of type epoxy resin (epoxy equivalent 230), “C-3” is 70% carbitol of Epicron N-680 (Cresol novolak type resin made by Dainippon Ink and Chemicals, epoxy equivalent 214) A tall acetate solution, “C-4” indicates triglycidyl isocyanurate (TEPIC-SP) manufactured by Nissan Chemical Co., Ltd.

  The performance of each photosensitive resin composition and the printed wiring board finally formed with the solder resist was evaluated by the following test methods. The results are shown in Table 1.

(Tackiness)
In the exposure process, the negative mask is directly applied to the surface of the dry film, and after irradiating the optimum exposure amount of ultraviolet rays in each solder resist composition, the adhesive state when removing the negative mask and the finger touch of the dry film are as follows. The evaluation criteria were evaluated.
A: When the negative mask was removed, no peeling resistance was felt and there was no sticking mark. Also, no stickiness was felt by touching the finger.
○: Adhesion was not felt when the negative mask was removed, but a slight sticking mark of the mask was observed on the dry film. Also, it felt faintly even when touched by a finger.
Δ: Slight peeling resistance was felt when removing the negative mask, and mask marks were observed on the dried film. In addition, a slight adhesion was felt by finger touch.
X: It was difficult to remove the negative mask, and the mask pattern was damaged when it was forcibly removed. A noticeable adhesion was felt even by finger touch.

(Acid resistance)
After immersing the test piece in 10% hydrochloric acid for 1 hour at room temperature, the appearance of the solder resist layer was observed and evaluated. The evaluation method is as follows.
A: No abnormality occurs.
○: A slight change is observed.
Δ: A slight change is observed.
X: A big change such as peeling on the coating film is observed.

(Alkali resistance and developability)
In the exposure process, a pattern shape of the formed solder resist layer was observed using a negative mask on which a concentric solder resist layer having a line width and a line spacing of 40 μm was formed, and evaluated as follows.
A: A sharp concentric pattern was formed.
○: Concentric patterns were formed, but there was slight unevenness in the line spacing and line width uniformity.
(Triangle | delta): Although the concentric pattern was formed, there was a resin residue or a missing part in a part.

(Adhesion)
According to the test method of JIS D0202, cross-cuts were made in a grid pattern on the solder resist layer of the test piece, and then the state of peeling after the peeling test with a cellophane adhesive tape was visually determined according to the following criteria.
A: No change is observed in all of the 100 crosscut portions.
◯: Slightly raised at one place out of 100 crosscut parts.
Δ: Peeling occurred at 2 to 10 of 100 cross cut portions.
X: Peeling occurred at 11 to 100 of 100 cross cut portions.

(PCT characteristics)
After leaving the test piece in saturated steam at a temperature of 121 ° C. for 50 hours, the appearance of the solder resist layer of this test piece was observed, and the result was judged according to the following criteria.
A: No change such as blistering, peeling or discoloration is observed.
○: Slight changes such as blistering, peeling, and discoloration are observed.
Δ: Slight changes such as blistering, peeling, and discoloration are observed.
X: Changes such as blistering, peeling, and discoloration are recognized.

(Plating resistance)
The test piece was plated using a commercially available electroless nickel plating bath and electroless gold plating bath, and the state of plating was observed. Moreover, the adhesion state of the soldering resist layer after plating was observed by performing the cellophane adhesive tape peeling test with respect to the soldering resist layer. The evaluation method is as follows.
A: There was no change in appearance, peeling at the time of tape peeling, or any penetration of plating.
○: No change in appearance, and no peeling occurred when the tape was peeled off. A very small amount of plating was found in the end portion of the resist.
Δ: Appearance is not changed, but some peeling is observed at the time of tape peeling.
X: The solder resist layer is lifted and peeling is observed when the tape is peeled off.

(Solder heat resistance)
LONCO 3355-11 (water-soluble flux manufactured by London Chemical Co., Ltd.) was used as a flux. First, the flux was applied to the test piece, and then immersed in a molten solder bath at 260 ° C. for 15 seconds, and then washed with water. The degree of surface whitening after performing this cycle three times was observed.

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

(UV yellowing resistance)
The exposure light amount in the exposure process was set to 100 J / cm ² , the appearance of the dried film before and after the exposure was compared, the degree of yellowing was confirmed, and the following evaluation was performed.
A: No change in appearance.
○: Almost no change in appearance.
Δ: Some yellowing is observed.
X: Significant yellowing is observed.

(Heat-resistant yellowing)
The substrate immediately after application of the solder resist composition was compared with that stored at 150 ° C. for 100 hours, and the degree of yellowing of the coating film was evaluated as follows.
A: No change in appearance.
○: Almost no change in appearance.
Δ: Some yellowing is observed.
X: Significant yellowing is observed.

(Pencil hardness)
The pencil hardness of the solder resist layer was measured and evaluated according to JIS K5400 using Mitsubishi High Uni (manufactured by Mitsubishi Pencil Co., Ltd.).

Claims (5)

It contains the following components A1, B1, C and D, the aromatic ring-containing epoxy resin in the following components A1 is, a photosensitive resin composition which comprises a cresol novolak type epoxy resin or a naphthalene type epoxy resin;
A1 a photosensitive resin obtained from a hydrogenated epoxy resin obtained by hydrogenating an aromatic ring-containing epoxy resin and having at least two ethylenically unsaturated groups in one molecule
B1 an epoxy compound having at least two epoxy groups in one molecule,
C photopolymerization initiator,
D Diluent.   The photosensitive resin composition according to claim 1, wherein the hydrogenation rate of the aromatic ring of the hydrogenated epoxy resin in the component A1 is 50% or more. The photosensitive resin composition of Claim 1 or 2 containing the following component E.
E White colorant   A composition for solder resist, comprising the photosensitive resin composition according to any one of claims 1 to 3.   A printed wiring board comprising a solder resist layer formed from the solder resist composition according to claim 4.