JP5513965B2 - Solder resist composition and printed wiring board - Google Patents

Description

  The present invention relates to a solder resist composition capable of forming a solder resist layer having high light reflectivity, and a printed wiring board including a solder resist layer formed from the solder resist composition.

  In recent years, as a resist pattern forming method for various printed wiring boards for consumer and industrial use, in order to cope with higher wiring density, instead of screen printing method, a dry film or liquid that has excellent resolution and dimensional accuracy, etc. A method using a developable solder resist composition has been occupied.

  In recent years, optical elements such as light emitting diodes used for backlights of liquid crystal displays such as portable terminals, personal computers, and televisions, and light sources of lighting fixtures have been directly mounted on printed wiring boards having a solder resist layer. Is increasing. In this case, by adding a white pigment such as titanium oxide to the solder resist layer, the light reflectivity of the solder resist layer is improved and the amount of light emitted from the device is increased. Such a solder resist layer is formed from, for example, a solder resist composition containing a photosensitive resin and titanium oxide. A solder resist layer having light reflectivity is formed by applying such a solder resist composition onto a printed wiring board, and then exposing and developing (see Patent Document 1).

JP 2007-322546 A

  However, white pigments such as titanium oxide have a large absorption in the ultraviolet region with a wavelength of 400 nm or less. For this reason, when titanium oxide is contained in the solder resist composition, the titanium oxide absorbs ultraviolet rays when the solder resist composition is exposed to ultraviolet rays, and the cumulative amount of irradiation light required for the exposure of the solder resist composition increases. Resulting in. On the other hand, in order to avoid absorption of irradiation light by the white pigment, a photopolymerization initiator that reacts with light having a wavelength of 400 nm or more is contained in the solder resist composition, and light having a wavelength of 400 nm is irradiated when the solder resist composition is exposed. It is also possible. However, since the white pigment reflects light having a wavelength of 400 nm or more well, the cumulative amount of irradiation light required for the exposure of the solder resist composition also increases. For this reason, productivity, such as a printed wiring board provided with a soldering resist layer, was bad.

  In addition, devices equipped with light emitting diodes are required to increase the amount of light emitted more and more, and therefore, further improvement in the light reflectivity of the solder resist layer is required.

  The present invention has been made in view of the above circumstances, and a solder resist composition capable of forming a solder resist layer having a high light reflectivity while containing a white pigment, suppressing the amount of light required for exposure, and the solder. It aims at providing a printed wiring board provided with the soldering resist layer formed from the resist composition.

  The solder resist composition according to the present invention contains a photosensitive resin, a white pigment, a photopolymerization initiator that is activated by light having a wavelength of 400 nm or more, and a fluorescent dye.

  The solder resist composition according to the present invention may contain an acylphosphine oxide photopolymerization initiator as the photopolymerization initiator.

  The solder resist composition according to the present invention may further contain α-hydroxyacetophenone as the photopolymerization initiator.

  In the solder resist composition according to the present invention, the content of the fluorescent dye may be in the range of 0.0001 to 80% by mass with respect to the content of the photopolymerization initiator.

  The solder resist composition according to the present invention is an ethylenically unsaturated compound having an epoxy group, which is obtained by polymerizing an ethylenically unsaturated compound containing an ethylenically unsaturated compound having a carboxyl group as the photosensitive resin. You may contain the photosensitive resin obtained by making this react.

  The solder resist composition according to the present invention may further contain an epoxy compound having at least two epoxy groups in one molecule.

  The solder resist composition according to the present invention may further contain a photopolymerizable compound selected from a photopolymerizable monomer and a prepolymer.

  In the solder resist composition according to the present invention, the ratio of the aromatic ring to the entire resin component in the solder resist composition may be in the range of 0.1 to 50% by mass.

  The printed wiring board concerning this invention is equipped with the soldering resist layer formed from the said soldering resist composition.

  ADVANTAGE OF THE INVENTION According to this invention, while containing a white pigment, the light quantity required for exposure is suppressed and the soldering resist composition which can form the soldering resist layer which has high light reflectivity is obtained.

  Moreover, according to this invention, while containing a white pigment, the light quantity required for exposure is suppressed and a printed wiring board provided with the soldering resist layer which has high light reflectivity is obtained.

  The solder resist composition contains a photosensitive resin, a white pigment, a photopolymerization initiator that is activated by light having a wavelength of 400 nm or more, and a fluorescent dye. First, each component contained in the solder resist composition will be described.

[Photosensitive resin]
The photosensitive resin has at least two ethylenically unsaturated groups in one molecule. The weight average molecular weight of the photosensitive resin is not particularly limited, but a preferable range is 3000 to 400,000. In this range, particularly excellent photosensitivity and resolution are imparted to the solder resist composition.

  The acid value of the photosensitive resin is preferably in the range of 25 to 150 mgKOH / g. If this acid value is 25 mgKOH / g or more, good developability is imparted to the solder resist composition. If the acid value is 150 mgKOH / g or less, the residual amount of carboxyl groups in the solder resist layer formed from the solder resist composition is reduced, and the solder resist layer has good electrical properties, electric corrosion resistance, water resistance, etc. Is maintained. In particular, when the acid value of the photosensitive resin is 40 to 100 mgKOH / g, the optimum effect is obtained.

  The ratio of the total amount of the photosensitive resin in the solder resist composition is not particularly limited, but is sensitive to the total amount of the components of the solder resist composition (excluding this organic solvent when the solder resist composition contains an organic solvent). The ratio of the total amount of the resin is desirably in the range of 10 to 80% by mass. In this case, good sensitivity and working characteristics of the solder resist composition and good physical properties of the solder resist layer are sufficiently ensured. The solder resist composition may contain only one type of photosensitive resin, or may contain two or more types.

  The solder resist composition may contain a photosensitive resin having an aromatic ring. In this case, the solder resist composition may include only a photosensitive resin having an aromatic ring, or may include a photosensitive resin having an aromatic ring and a photosensitive resin not having an aromatic ring.

  The solder resist composition may contain, for example, at least one of the following photosensitive resin (A1) and photosensitive resin (A2) as the photosensitive resin.

(Photosensitive resin (A1))
The photosensitive resin (A1) comprises an epoxy compound (a) having two or more epoxy groups in one molecule, an ethylenically unsaturated compound (b) having a carboxyl group, a saturated or unsaturated acid anhydride ( It is produced by reacting with c). In particular, if at least one of the epoxy compound (a), the ethylenically unsaturated compound (b) having a carboxyl group, and the acid anhydride (c) is a compound having an aromatic ring, a photosensitive resin having an aromatic ring ( A1) is generated. Since this photosensitive resin (A1) has a carboxyl group derived from the acid anhydride (c), when the solder resist composition contains the photosensitive resin (A1), the solder resist composition has developability with an alkaline solution. Demonstrate.

  When the epoxy compound (a) is an epoxy resin having an aromatic ring, the photosensitive resin (A1) has an aromatic ring derived from the epoxy compound (a). Examples of the epoxy resin having an aromatic ring include novolac type epoxy resins. A novolak-type epoxy resin is produced by reacting various phenol novolak resins produced 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.

  Examples of the epoxy resin having an aromatic ring include naphthalene type epoxy resins and biphenyl type epoxy resins.

  The epoxy compound (a) may be an epoxy resin having no aromatic ring. Examples of such epoxy resins include triglycidyl isocyanurate and alicyclic epoxy resins.

  In the epoxy compound (a), an ethylenically unsaturated compound (d1) having an epoxy group and an ethylenically unsaturated compound (d2) other than the ethylenically unsaturated compound (d1) used as necessary are polymerized. The epoxy compound produced | generated by this may be sufficient. In this case, in particular, if at least one of the ethylenically unsaturated compound (d1) and the ethylenically unsaturated compound (d2) has an aromatic ring, the epoxy compound (a) has an aromatic ring. A photosensitive resin (A1) having an aromatic ring can be obtained from the compound (a).

  When the ethylenically unsaturated compound (d1) and the ethylenically unsaturated compound (d2) are used in combination, and only one of them (for example, only the ethylenically unsaturated compound (d2)) has an aromatic ring, By adjusting the blending ratio of the ethylenically unsaturated compound (d1) and the ethylenically unsaturated compound (d2), the amount of the aromatic ring of the photosensitive resin (A1) is easily adjusted, and as a result, in the solder resist composition The amount of the aromatic ring of the resin component is easily adjusted.

  As the ethylenically unsaturated compound (d1) having an epoxy group, an appropriate polymer or prepolymer may be mentioned. Specific examples of the ethylenically unsaturated compound (d1) include epoxy cyclohexyl 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 are used individually by 1 type, or multiple types are used together. In particular, glycidyl (meth) acrylate which is widely used and easily available is preferable.

  The ethylenically unsaturated compound (d2) may be any ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated compound (d1). Specific examples of the ethylenically unsaturated compound (d2) having an aromatic ring include 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) ) Acryloyloxypropyl phthalate, benzyl (meth) acrylate, neopentyl glycol benzoate (meth) acrylate, paracumylphenoxyethylene glycol (meth) acrylate, EO-modified cresol (meth) acrylate, ethoxylated phenyl (meth) acrylate, nonylphenoxy Polyethylene glycol (meth) acrylate (n = 2-17), ECH modified phenoxy (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy Xylhexaethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, PO-modified bisphenol A Di (meth) acrylate, modified bisphenol A di (meth) acrylate, EO modified bisphenol F di (meth) acrylate, ECH modified phthalic acid di (meth) acrylate, trimethylolpropane benzoate (meth) acrylate, EO modified phthalic acid (meta ) Acrylate, EO, PO modified phthalic acid (meth) acrylate, vinyl carbazole, styrene, N-phenylmaleimide, N-benzylmaleimide, 3-maleimidobenzoic acid N Succinimidyl, and the like.

  Specific examples of the ethylenically unsaturated compound (d2) having no aromatic ring include linear or branched aliphatic or alicyclic (however, the ring may partially have an unsaturated bond). (Meth) acrylic acid esters, hydroxyalkyl (meth) acrylates, alkoxyalkyl (meth) acrylates and the like; N-substituted maleimides such as N-cyclohexylmaleimide and the like. Along with these compounds, if necessary, ethylene in 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 polymerizable unsaturated groups may be used in combination. These compounds are used individually by 1 type, or multiple types are used together. These compounds are preferable in that the hardness and oiliness of the solder resist layer can be easily adjusted.

  The ethylenically unsaturated compound (d1) and the ethylenically unsaturated compound (d2) used as necessary react by a known polymerization method such as solution polymerization or emulsion polymerization. As a solution polymerization method, a mixture of the ethylenically unsaturated compound (d1) and the ethylenically unsaturated compound (d2) is mixed with nitrogen in an appropriate organic solvent in the presence of a polymerization initiator. Examples thereof include a method of heating and stirring in an atmosphere 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, and propylene glycol monomethyl ether acetate. And the like, and the like, and dialkyl glycol ethers. These may be used alone or in combination.

  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 may be used alone or in combination. In addition, a redox initiator may be used as the polymerization initiator.

  As the ethylenically unsaturated compound (b) having a carboxyl group, an appropriate polymer or prepolymer may be mentioned. Specific examples of the ethylenically unsaturated compound (b) include 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-carboxyethoxy) -3-oxypropyl ester, 2 -Ethylene such as acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, etc. Compounds having sex unsaturated group only one can be cited. This ethylenically unsaturated compound (b) has a hydroxyl group such as pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, etc. Examples also include compounds having a plurality of ethylenically unsaturated groups, such as compounds obtained by reacting dibasic acid anhydrides with polyfunctional acrylates or polyfunctional methacrylates. These compounds are used individually by 1 type, or multiple types are used together. In particular, the ethylenically unsaturated compound (b) preferably contains at least one of acrylic acid and methacrylic acid. In this case, since the ethylenically unsaturated group introduced into the photosensitive resin (A1) by acrylic acid and methacrylic acid is particularly excellent in photoreactivity, the photoreactivity of the photosensitive resin (A1) is increased.

  The amount of the ethylenically unsaturated compound (b) used at the time of synthesizing the photosensitive resin (A1) is such that the carboxyl group of the ethylenically unsaturated compound (b) is 0.1 per mol of the epoxy group of the epoxy compound (a). The amount is preferably in the range of 7 to 1.2 mol, and particularly preferably in the range of 0.9 to 1.1 mol of the carboxyl group. In this case, the residual amount of epoxy groups in the photosensitive resin (A1) is particularly reduced, and the photosensitive resin (A1) in the case where the solder resist composition is placed under weak heat drying conditions such as predrying. The thermosetting reaction is suppressed, and a decrease in developability after exposure of the solder resist composition is suppressed. Moreover, the residue of the ethylenically unsaturated compound (b) having an unreacted carboxyl group in the solder resist composition is suppressed.

  Specific examples of the saturated or unsaturated acid anhydride (c) include compounds having an aromatic ring such as phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methyl Examples thereof include dibasic acid anhydrides such as hexahydrophthalic anhydride, and acid anhydrides of three or more basic acids such as trimellitic anhydride, pyromellitic anhydride, and benzophenone tetracarboxylic anhydride. In addition, as compounds having no aromatic ring, dibasic acid anhydrides such as succinic anhydride, methyl succinic anhydride, maleic anhydride, citraconic anhydride, glutaric anhydride, itaconic anhydride, and methylcyclohexene tetracarboxylic anhydride, etc. And acid anhydrides of tribasic acids or more. These compounds are used individually by 1 type, or multiple types are used together.

  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 solder resist composition with a dilute aqueous alkali solution. The amount of the acid anhydride (c) used is such that the acid value of the photosensitive resin (A1) is preferably in the range of 25 to 150 mgKOH / g, particularly preferably in the range of 40 to 100 mgKOH / g.

  In advancing the addition reaction between the epoxy compound (a), the ethylenically unsaturated compound (b) having a carboxyl group, and the saturated or unsaturated acid anhydride (c), a known method can be employed. For example, in the addition reaction between the epoxy compound (a) 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 epoxy compound (a), Furthermore, if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed by stirring. By an ordinary method, the reaction is preferably carried out at a reaction temperature of preferably 60 to 150 ° C., particularly preferably 80 to 120 ° C. Can be obtained. 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, when the addition reaction between the addition reaction product and the saturated or unsaturated polybasic acid anhydride (c) is allowed to proceed, a saturated or unsaturated polybasic acid anhydride (c) is added to the solvent solution of the addition reaction product. ), And if necessary, a thermal polymerization inhibitor and a catalyst are added and mixed with stirring, and the reaction can be carried out by a conventional method. The reaction conditions can be the same as in the addition reaction of the epoxy compound (a) and the ethylenically unsaturated compound (b), and the thermal polymerization inhibitor and catalyst are the same as the epoxy compound (a) and the ethylenically unsaturated compound. The thermal polymerization inhibitor and catalyst used for the addition reaction with the saturated compound (b) can be used as they are.

(Photosensitive resin (A2))
The photosensitive resin (A2) is composed of an ethylenically unsaturated compound (an ethylenically unsaturated compound (b) having a carboxyl group) and an ethylene used as necessary. It can be obtained by reacting an ethylenically unsaturated compound (d1) having an epoxy group with a compound obtained by polymerizing the polymerizable unsaturated compound (d2)). In this case, if at least one of the ethylenically unsaturated compound (b), the ethylenically unsaturated compound (d2), and the ethylenically unsaturated compound (d1) is a compound having an aromatic ring, the photosensitivity having an aromatic ring. Resin (A2) is obtained. In particular, when the ethylenically unsaturated compound (b) and the ethylenically unsaturated compound (d2) are used in combination, and only one of them (for example, only the ethylenically unsaturated compound (d2)) has an aromatic ring, The amount of the aromatic ring of the photosensitive resin (A2) is easily adjusted by adjusting the blending ratio of the photosensitive unsaturated compound (b) and the ethylenically unsaturated compound (d2), and as a result, in the solder resist composition The amount of the aromatic ring of the resin component is easily adjusted.

  Moreover, since this photosensitive resin (A2) has a residual carboxyl group derived from the ethylenically unsaturated compound (b), when the photosensitive resin (A2) is blended in the solder resist composition, this solder resist composition The developability with an alkaline solution is imparted to.

  Specific examples of the ethylenically unsaturated compound (b), the ethylenically unsaturated compound (d2) and the ethylenically unsaturated compound (d1) used in the synthesis of the photosensitive resin (A2) include the photosensitive resin ( Examples include ethylenically unsaturated compounds (b), ethylenically unsaturated compounds (d2) and ethylenically unsaturated compounds (d1) used in the synthesis of A1).

  The ethylenically unsaturated compound (b) and the ethylenically unsaturated compound (d2) used as necessary are known polymerization methods, for example, an ethylenically unsaturated compound applied during the synthesis of the photosensitive resin (A1). The reaction (polymerization reaction) can be carried out in the same manner as in the case of the reaction between (d1) and the ethylenically unsaturated compound (d2).

  In addition, the compound obtained by this reaction and the ethylenically unsaturated compound (d1) are known methods, for example, the ethylenically unsaturated compound (b) or acid anhydride applied during the synthesis of the photosensitive resin (A1). It can be made to react by the same method as the addition reaction of (c).

  The amount of the ethylenically unsaturated compound (d1) having an epoxy group is such that the unreacted carboxyl group remains in the photosensitive resin (A2), and the photosensitive resin (A2) has a sufficient acid value. An amount is preferred. In this case, the acid value of the photosensitive resin (A2) is preferably in the range of 25 to 150 mgKOH / g, particularly preferably in the range of 40 to 100 mgKOH / g.

[White pigment]
When the solder resist composition contains a white pigment, the solder resist layer exhibits high light reflectivity. Examples of white pigments include titanium oxide, barium sulfate, magnesium oxide, and calcium carbonate. The titanium oxide may be a titanium oxide having any structure of rutile type, anatase type, and ramsdellite type. The ramsdellite-type titanium oxide can be obtained by subjecting ramsdellite-type Li _0.5 TiO ₂ to a lithium desorption treatment by chemical oxidation. The solder resist composition may contain only one type of white pigment, or may contain two or more types.

  The proportion of the white pigment in the solder resist composition is preferably 5 to 80% by mass with respect to the total amount of components in the solder resist composition (excluding the organic solvent when the solder resist composition contains an organic solvent). More preferably, it is the range of 15-50 mass%. If this proportion is 5% by mass or more, the solder resist layer exhibits high concealability and whiteness, and if this proportion is 80% by mass or less, it is required for resists such as heat resistance and pencil hardness of the solder resist layer. The physical properties are maintained at a high level.

(Photopolymerization initiator)
The photopolymerization initiator is preferably a compound that is activated by absorbing light having a wavelength longer than 400 nm. In this case, the light in the wavelength region longer than 400 nm is not easily absorbed by the white pigment such as titanium oxide, so that the exposure efficiency of the solder resist composition is improved. Furthermore, the photopolymerization initiator is preferably a compound that hardly undergoes discoloration due to ultraviolet rays or heat.

  The photopolymerization initiator is particularly preferably an acylphosphine oxide photopolymerization initiator. Specific examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (DAROCUR TPO), 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate ( SPEEDCURE TPO-L), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (IRGACURE 819), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide ( CGI 403).

  As the photopolymerization initiator, α-hydroxyacetophenone may be used together with the acylphosphine oxide photopolymerization initiator. α-Hydroxyacetophenone is less susceptible to oxygen damage than acylphosphine oxide photopolymerization initiators and is less likely to discolor due to heat. For this reason, when (alpha) -hydroxy acetophenone is used, the sclerosis | hardenability of the surface layer at the time of exposure of a soldering resist composition becomes high especially. Specific examples of α-hydroxyacetophenone include 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (DAROCUR 1173), 1- [4 -(2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (IRGACURE 2959) and the like.

  When the solder resist composition contains an acylphosphine oxide photopolymerization initiator and α-hydroxyacetophenone, the content of the acylphosphine oxide photopolymerization initiator is in the range of 0.1 to 20% by mass, α- The content of hydroxyacetophenone is preferably in the range of 0.1 to 20% by mass. In this case, the photocurability of the solder resist composition is sufficiently maintained, the hardness of the solder resist layer is further improved, and the developer resistance of the solder resist layer is improved. For this reason, in particular, the resistance to electroless Ni plating of the solder resist layer is improved.

  The blending amount of the photopolymerization initiator in the solder resist composition is appropriately set in consideration of the balance between the photocurability of the solder resist composition and the physical properties of the solder resist layer formed from the solder resist composition. In particular, the total amount of the components of the solder resist composition (excluding the organic solvent when the solder resist composition contains an organic solvent) is preferably in the range of 0.1 to 30% by mass.

[Fluorescent dye]
The fluorescent dye (fluorescent whitening agent) absorbs light having a wavelength of 200 to 400 nm and emits light having a wavelength of 400 to 500 nm. Such fluorescent dyes include benzoxazoyl derivatives with naphthalene as substituents, benzoxazoyl derivatives with thiophene as substituents, benzoxazoyl derivatives with stilbene as substituents, coumarin derivatives, styrene biphenyl derivatives, pyrazolone derivatives, bis (triazinylamino) And stilbene disulfonic acid derivatives.

  When the solder resist composition contains the fluorescent dye as described above and an acylphosphine oxide photopolymerization initiator having absorption in a wavelength region longer than 400 nm, the fluorescent dye functions as a sensitizer for the photopolymerization initiator. In this embodiment, since the solder resist composition contains a white pigment and the white pigment reflects light at the time of exposure, the effect as a sensitizer of a fluorescent dye is great.

  Further, since the fluorescent dye absorbs light in the ultraviolet wavelength region and emits light in the blue wavelength region, when the solder resist composition contains the fluorescent dye, the reflectance of the blue wavelength region of the solder resist layer is improved.

  The amount of the fluorescent dye in the solder resist composition is preferably in the range of 0.0001 to 80% by mass with respect to the amount of the photopolymerizable initiator in the solder resist composition. The amount of the fluorescent dye is preferably in the range of 1 to 30% by mass with respect to the amount of the photopolymerizable initiator, and in the range of 0.04-2% with respect to the total amount of the solder resist composition. Preferably there is.

[Epoxy compound]
The solder resist composition may contain an epoxy compound having at least two epoxy groups in one molecule. This epoxy compound may be a poorly solvent-soluble epoxy compound or a general-purpose solvent-soluble epoxy compound. The type of the epoxy compound 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, bisphenol A-novolac type epoxy Resins are desirable. The triglycidyl isocyanurate is preferably a β-form having a structure in which three epoxy groups are bonded in the same direction with respect to the S-triazine ring skeleton plane, or 1 for the β-form and the S-triazine ring skeleton plane. A mixture with an α-isomer having a structure in which one epoxy group is bonded to a different direction from the other two epoxy groups is preferable.

  The ratio of the epoxy compound in the solder resist composition is not particularly limited, but the total amount of the epoxy compound relative to the total amount of the components of the solder resist composition (excluding this organic solvent when the solder resist composition contains an organic solvent). The ratio is preferably 0.1% by mass or more. In this case, the solder resistance, plating resistance, etc. of the solder resist layer are further improved. Moreover, if this ratio is 50 weight% or less, the developability of the solder resist composition is further improved.

[Photopolymerizable compound]
The solder resist composition may contain a photopolymerizable compound other than the photosensitive resin. The photopolymerizable compound is selected from monomers and prepolymers having photopolymerizability. For example, the photopolymerizable compound may be prepared by diluting the solder resist composition so as to be easily applied, adjusting the acid value of the entire solder resist composition, or improving the photopolymerizability of the solder resist composition. Used for the purpose. Examples of the photopolymerizable compound include appropriate monomers or prepolymers having photopolymerizability. Specific examples of this photopolymerizable compound include monofunctional acrylates such as 2-hydroxyethyl acrylate; diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tris. Examples thereof include polyfunctional (meth) acrylates such as (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. Such a compound is used individually by 1 type, or multiple types are used together.

  When using a photopolymerizable compound, the compounding amount of the photopolymerizable compound in the solder resist composition is the total amount of the components of the solder resist composition (in the case where the solder resist composition contains an organic solvent, this organic solvent is included). ) Is preferably in the range of 0.05 to 40% by mass. Further, when the solder resist composition contains an organic solvent, the blending amount is preferably 50% by mass or less in the total amount of the components of the solder resist composition excluding the organic solvent. In this case, the surface adhesiveness of the dry film formed from the solder resist composition is suppressed, and the negative mask is prevented from being damaged when the negative mask on which the pattern is drawn and the dry film are exposed in direct contact with each other. Is done.

〔Organic solvent〕
The solder resist composition may contain an organic solvent as necessary. When the resin component is dissolved by the organic solvent or the solder resist composition is diluted, the solder resist composition becomes liquid and its viscosity is adjusted, thereby improving the coatability of the solder resist composition. The organic solvent is also used for improving the film forming property when the solder resist composition is dried.

  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 are used individually by 1 type, or multiple types are used together.

  The blending amount of the organic solvent in the solder resist composition is appropriately set. This blending amount is preferably adjusted so that the organic solvent is volatilized quickly when the coating film formed from the solder resist composition is temporarily dried, that is, the organic solvent does not remain in the dried film. The blending amount of the organic solvent is preferably in the range of 5 to 99.5% by weight in the total amount of the components of the solder resist composition, and in this case, good coatability of the solder resist composition is maintained. In addition, since the suitable compounding quantity of an organic solvent changes with coating methods, it is preferable that a compounding quantity is adjusted suitably according to the coating method.

[Other ingredients]
In addition to the above-described components, the solder resist composition includes, for example, tolylene diisocyanate, morpholine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate blocked isocyanate, melamine, n- Thermosetting components such as amino resins such as butylated melamine resin, isobutylated melamine resin, butylated urea resin, butylated melamine urea cocondensation resin, benzoguanamine cocondensation resin; UV curable epoxy (meth) acrylate; bisphenol A type (Meth) acrylic acid adducts such as phenol novolac type, cresol novolak type, alicyclic epoxy resin; diallyl phthalate resin, phenoxy resin, melamine resin, urethane resin, fluorine resin, etc. Molecular compound etc. may be contained as appropriate.

  Further, the solder resist composition is optionally a curing agent that cures the epoxy resin; a curing accelerator; a colorant other than white; a copolymer such as silicone or acrylate; a leveling agent; an adhesive property such as a silane coupling agent. An imparting agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; an antioxidant surfactant;

[Preparation of solder resist composition]
The raw material components as described above are blended, and the solder resist composition is prepared by kneading by a known kneading method using, for example, a three-roll, ball mill, sand mill or the like. A part of the raw material components, for example, a photopolymerizable compound, a part of the organic solvent, and an epoxy compound are mixed in advance, the remaining raw material components are mixed in advance, and both are further mixed at the time of use, so that the solder resist A composition may be prepared.

  The ratio of the aromatic ring in the resin component to the entire polymerization reactive compound (hereinafter referred to as the resin component) in the solder resist composition is preferably in the range of 0.1 to 50% by mass. Examples of the resin component include a photosensitive resin, an epoxy compound, and a photopolymerizable compound. In particular, this ratio is preferably in the range of 1 to 35% by mass. The amount of the aromatic ring is a value based on the entire resin component, and a component having an aromatic ring and a component having no aromatic ring may be mixed in the resin component. “Aromatic ring” refers to an aromatic ring composed of hydrocarbons, particularly a benzene ring (including a benzene ring constituting a condensed ring). Heterocycles are not included in aromatic rings.

  In this case, by containing a resin component having an aromatic ring, good characteristics of the solder resist layer formed from the solder resist composition are maintained, and the amount of the aromatic ring in the resin component is within the specific range. Thus, deterioration of the solder resist layer due to light is suppressed, and yellowing of the solder resist layer is suppressed.

[Formation of solder resist layer on printed wiring board]
A solder resist layer is formed by coating and forming a solder resist composition. When the solder resist layer is formed on the printed wiring board, a printed wiring board provided with the solder resist layer is obtained.

  The method for forming the solder resist layer is not particularly limited. An example of the most common method for forming a solder resist layer is shown below.

  After the solder resist composition is applied to the printed wiring board by an appropriate method such as dipping, spraying, spin coating, roll coating, curtain coating, screen printing, etc., it is heated at 60 to 120 ° C. and preliminarily dried. The organic solvent in the solder resist composition is volatilized. Thereby, a dry film (preliminary dry film) is formed.

  The negative mask on which the pattern is drawn is disposed so as to contact the dry film, or is spaced from the dry film. Examples of the negative mask include photo tools such as a mask film and a dry plate. The dry film is exposed by irradiating the dry film with ultraviolet rays through the negative mask. Ultraviolet rays are irradiated from an ultraviolet 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 may be adopted, for example, a direct drawing method using laser exposure or the like may be adopted.

  When the dried film of the solder resist composition is exposed in this manner, the cured reaction of the photosensitive resin proceeds in the exposed portion, and this portion is cured. At this time, the white pigment in the solder resist composition absorbs an ultraviolet region having a wavelength of 400 nm or less, but since the fluorescent dye in the solder resist composition also absorbs ultraviolet rays, the amount of ultraviolet rays absorbed by the white pigment is reduced. The fluorescent paint that has absorbed ultraviolet rays emits light having a wavelength of 400 to 500 nm, and the photopolymerization initiator is activated by absorbing the light by the photopolymerization initiator. That is, the fluorescent dye acts as a sensitizer. Thereby, the curing reaction of the photosensitive resin proceeds.

  Thus, even if ultraviolet rays are used for the exposure of the solder resist composition, the amount of ultraviolet rays absorbed by the white pigment is reduced and further absorbed by the fluorescent dye absorbing the ultraviolet rays in the solder resist composition. The curing reaction of the photosensitive resin proceeds efficiently by the sensitizing action of the fluorescent dye. For this reason, exposure efficiency becomes high.

  By subjecting the exposed dry film to development processing, the unexposed portion of the dry film is removed, and the exposed portion of the dry film remaining on the printed wiring board becomes a solder resist layer. .

  In the development process, an appropriate developer corresponding to the composition of the solder resist composition is used. Specific examples of the developer include 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, water An alkaline solution such as an aqueous lithium oxide solution may be mentioned. In addition to the alkaline solution, organic amines such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine may be used. These developers are used alone or in combination. The solvent of the alkaline solution is not limited to water alone, but may be a mixture of water and a hydrophilic organic solvent such as lower alcohols.

  When the solder resist composition contains an epoxy compound, the solder resist layer may be subjected to heat treatment at 120 to 180 ° C. for about 30 to 90 minutes as necessary. In this case, the thermosetting reaction of the epoxy compound proceeds, and the film strength, hardness, chemical resistance, etc. of the solder resist layer are improved.

  Since the solder resist layer thus formed contains a white pigment, it has high light reflectivity. For this reason, when a light-emitting element such as a light-emitting diode is mounted on a printed wiring board provided with a solder resist layer, the light emitted from the light-emitting element is reflected by the solder resist layer with high efficiency, and light is emitted from a device including the light-emitting diode. The amount of light increases. Furthermore, in this embodiment, since the fluorescent dye is contained in the solder resist layer, the solder resist layer emits visible light when irradiated with ultraviolet rays. For this reason, especially when the light emitted from the light emitting diode contains ultraviolet light, the amount of visible light emitted from the device equipped with the light emitting diode is greatly improved.

[Synthesis Example 1]
A four-necked flask equipped with a reflux condenser, a thermometer, a glass tube for nitrogen substitution, and a stirrer, 42 parts by mass of methacrylic acid, 43 parts by mass of methyl methacrylate, 35 parts by mass of styrene, 35 parts by mass of benzyl acrylate, carbitol acetate 100 parts by mass, 0.5 parts by mass of lauryl mercaptan, and 4 parts by mass of azobisisobutyronitrile were added. The liquid in the four-necked flask was heated at 75 ° C. for 5 hours under a nitrogen stream to advance the polymerization reaction, thereby obtaining a copolymer solution having a concentration of 50% by mass.

  To this copolymer solution, 0.05 part by weight of hydroquinone, 23 parts by weight of glycidyl methacrylate and 2.0 parts by weight of dimethylbenzylamine were added, and after 24 hours of addition reaction at 80 ° C., 35 parts by weight of carbitol acetate was added. By adding, the solution (photosensitive resin solution A) of the photosensitive resin with a density | concentration of 50 mass% was obtained.

[Synthesis Example 2]
In a four-necked flask equipped with a reflux condenser, a thermometer, a glass tube for nitrogen substitution and a stirrer, 120 parts by mass of glycidyl methacrylate, 25 parts by mass of methyl methacrylate, 20 parts by mass of t-butyl acrylate, 35 parts by mass of t-butyl methacrylate Part, 200 parts by weight of carbitol acetate, and 18.4 parts by weight of azobisisobutyronitrile were added. The liquid in the four-necked flask was heated at 95 ° C. for 8 hours under a nitrogen stream to advance the polymerization reaction, thereby obtaining a copolymer solution having a concentration of 50% by mass.

  To this copolymer solution, 0.2 part by mass of hydroquinone, 73.9 parts by mass of acrylic acid, and 2.0 parts by mass of dimethylbenzylamine were added and heated at 110 ° C. for 10 hours to proceed the addition reaction. By adding 60.8 parts by mass of phthalic anhydride and 16.5 parts by mass of carbitol acetate and heating at 81 ° C. for 3 hours to proceed the reaction, a solution of photosensitive resin having a concentration of 60% by mass (photosensitive resin) Solution B) was obtained.

[Examples 1 to 10 and Comparative Examples 1 and 2]
To the solution of the photosensitive resin produced in each of the above synthesis examples, the blending components of each blending composition shown in Table 1 were added and kneaded with three rolls to obtain a solder resist composition.

  In Examples 1 to 10 and Comparative Example 1, the amount of aromatic rings relative to the total amount of resin components is 23.2% by mass, and in Comparative Example 2, the amount of aromatic rings relative to the total amount of resin components is 0% by mass.

Details of the raw material components shown in Table 1 are as follows.
Epoxy compound: triglycidyl isocyanurate (β-form having a structure in which three epoxy groups are bonded to the S-triazine ring skeleton surface in the same direction).
DPHA: dipentaerystol hexaacrylate.
-Titanium oxide: manufactured by Ishihara Sangyo Co., Ltd., product number CR-90.
-Lucillin TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide manufactured by BASF
IRGACURE 184: manufactured by Ciba Specialty Chemicals, 1-hydroxy-cyclohexyl-phenyl-ketone melamine resin: manufactured by Nissan Chemical Industries, Ltd., fine melamine.
Silicone: Shin-Etsu Silicone Co., Ltd., product number KS-66.
TINOPAL OB: manufactured by Ciba Japan, 2,5-thiophenediylbis (5-tert-butyl-1,3-benzoxazole.
-Hostalux KCB: manufactured by Clariant Japan Co., Ltd., naphthalene benzoxazoyl derivative.

〔Evaluation test〕
Each solder resist composition was coated by screen printing on the entire surface of a glass epoxy base copper-clad laminate having a 35 μm thick copper foil and a printed wiring board that had been previously etched to form a pattern. A wet paint film was formed on.

  This wet coating film was preliminarily dried by heating at 80 ° C. for 20 minutes to obtain a dry coating film having a thickness of 20 μm.

A negative mask was directly applied to the surface of the dried coating film, and ultraviolet rays were irradiated under conditions of an irradiation energy density of 350 mJ / cm ² to selectively expose the dried coating film on the substrate surface.

The dried coating film after exposure was developed with an aqueous sodium carbonate solution to leave the exposed and cured portion of the dried coating film on the substrate. The exposed and cured portion of the dried coating film was heated at 150 ° C. for 60 minutes for thermal curing. By doing so, a solder resist layer was formed, and a test piece provided with the solder resist layer was obtained.

(Sensitivity (ST))
At the time of preparing the test piece, an exposure test mask “Step Tablet PHOTEC 21-stage” manufactured by Hitachi Chemical Co., Ltd. was directly applied to the pre-dried coating film and adhered under reduced pressure. Using a reduced pressure contact type double-side exposure machine “ORC HMW680GW” manufactured by Oak Seisakusho, the pre-dried coating film was irradiated with ultraviolet rays under the condition of an irradiation energy density of 350 mJ / cm ² through an exposure test mask. Subsequently, development was performed using a developer (a sodium carbonate aqueous solution having a concentration of 1% by mass). The remaining step level in this case was determined.

(Dam remaining)
A wet coating film is formed on the wiring board by applying a solder resist composition to a wiring board having a copper conductor wiring having a line width / line spacing of 0.2 mm / 0.3 mm and a thickness of 40 μm by a screen printing method. Formed.

  This wet coating film was preliminarily dried by heating at 80 ° C. for 20 minutes to form a dry coating film having a thickness of 20 μm.

A mask pattern that forms solder dams with a width of 25 μm, 50 μm, 75 μm, and 100 μm is applied to the dried coating film, and ultraviolet rays are irradiated under the condition of an irradiation energy density of 350 mJ / cm ² to form a dried coating film on the wiring board. Selective exposure.

  The exposed dried coating film was developed with an aqueous sodium carbonate solution to leave the exposed and cured portion of the dried coating film on the wiring board.

  The exposed cured portion of the dried coating film was heated and cured at 150 ° C. for 60 minutes, thereby forming a solder resist layer including a solder dam having a thickness of 60 μm on the wiring board.

  A cellophane adhesive tape peeling test was performed on the solder dam on the wiring board, and the width of the solder dam remaining without peeling was evaluated. When all the solder dams were peeled off, it was evaluated as x.

(Exposure light intensity evaluation)
In the dam remainder of the test, the irradiation energy density at the time of exposure of the dry film, is changed in 50 mJ / cm ² increments in the range of 200 to 600 mJ / cm ^2, minimum required in order to dam the remaining evaluation is 75μm We investigated the irradiation energy density. In this test, when the evaluation of the remaining dam was not 75 μm, it was evaluated as x.

(Tackiness)
When the negative mask was removed at the time of exposure, the adhesion state of the dry coating film and the finger touch adhesion of the dry coating film were evaluated according to the following evaluation criteria.
A: No peeling resistance is felt when the negative mask is removed, and there is no sticking mark. It doesn't feel sticky even by finger touch.
◯: Adhesion is not felt when the negative mask is removed, but a slight sticking mark of the mask is observed on the dry film. Adhesion is also felt slightly by touch.
Δ: Slight peeling resistance is felt when removing the negative mask, and mask marks are observed on the dry film. Slight adhesion is also felt by finger touch.
X: It is difficult to remove the negative mask, and the mask pattern is damaged when it is forcibly removed. A noticeable adhesion is also felt by finger touch.

(Acid resistance)
After immersing the test piece in hydrochloric acid having a concentration of 10% by mass at room temperature for 1 hour, 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)
Using a negative mask in which a concentric solder resist layer having a line width and a line spacing of 40 μm was formed in the exposure process, the pattern shape of the solder resist layer formed to a thickness of 20 μm was observed and evaluated as follows. .
A: A sharp concentric pattern is formed.
○: Concentric patterns are formed, but there is slight unevenness in the uniformity of the line spacing and line width.
Δ: A concentric pattern is formed, but there is a slight resin residue or missing in a part thereof.

(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 floating is observed at one place out of 100 crosscut portions.
(Triangle | delta): Peeling is recognized by 2-10 places among 100 crosscut parts.
X: Peeling is observed at 11 to 100 places out of 100 crosscut portions.

(PCT characteristics)
After leaving the test piece in saturated steam at a temperature of 121 ° C. for 50 hours, the appearance of the test piece solder resist layer 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: No change in appearance, peeling at the time of tape peeling, or penetration of plating is observed.
◯: No change in appearance was observed, and no peeling of the solder resist layer at the time of peeling of the tape was observed, but a slight penetration of plating was observed at the end portion of the resist.
Δ: No change in appearance is observed, but part of the solder resist layer is peeled off when the tape is peeled off.
X: Floating is observed in the solder resist layer, and peeling of the solder resist layer is observed during tape peeling.

(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 is observed.
○: Slight whitening is observed.
Δ: Whitening is observed.
X: Remarkable whitening is recognized.

(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.).

(Light resistance)
A solder resist layer was formed on the IPC B-25 comb-type electrode B coupon under the same conditions as in the case of the test piece, and a printed wiring board for evaluation was obtained. While applying a bias voltage of DC 100 V to the comb electrode of this printed wiring board for production evaluation, 40 ° C., 90% R.D. H. For 500 hours. The presence or absence of migration in the printed wiring board for evaluation after this test was confirmed and evaluated.

The evaluation method of the electric corrosion resistance is as follows.
A: Migration is not confirmed at all.
○: A slight migration is confirmed.
Δ: Some migration is confirmed.
X: Migration has occurred.

(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.

(Reflectance)
The reflectance of light having a wavelength of 450 nm of the solder resist layer in the test piece was measured with a spectrocolorimeter (model number CM-600d) manufactured by Konica Minolta Sensing Co., Ltd.

(Test results)
The results of the above evaluation tests are shown in Table 1 below.

Claims (9)

  A solder resist composition containing a photosensitive resin, a white pigment, a photopolymerization initiator activated by light having a wavelength of 400 nm or more, and a fluorescent dye.   The solder resist composition according to claim 1, comprising an acylphosphine oxide photopolymerization initiator as the photopolymerization initiator.   The solder resist composition according to claim 2, further comprising α-hydroxyacetophenone as the photopolymerization initiator.   The solder resist composition according to any one of claims 1 to 3, wherein a content of the fluorescent dye is in a range of 0.0001 to 80% by mass with respect to a content of the photopolymerization initiator.   A photosensitive resin obtained by reacting an ethylenically unsaturated compound having an epoxy group with a compound obtained by polymerizing an ethylenically unsaturated compound containing an ethylenically unsaturated compound having a carboxyl group as the photosensitive resin. The solder resist composition as described in any one of Claims 1 thru | or 4 containing.   Furthermore, the soldering resist composition as described in any one of Claims 1 thru | or 5 containing the epoxy compound which has an at least 2 epoxy group in 1 molecule.   Furthermore, the soldering resist composition as described in any one of the Claims 1 thru | or 6 containing the photopolymerizable compound selected from the monomer and prepolymer which have photopolymerizability.   The ratio of the aromatic ring with respect to the whole resin component is the range of 0.1-50 mass%, The soldering resist composition as described in any one of Claims 1 thru | or 7.   A printed wiring board provided with the soldering resist layer formed from the soldering resist composition as described in any one of Claims 1 thru | or 8.