JPH09137109A - Ink composition for photosetting liquid solder resist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reprove photosensitivity, adherence and chemical resistance,by including a photosetting resin and specific polymer particles. SOLUTION: (A) a photosetting resin is obtained by making 1 chemical equivalent of an epoxy group of an epoxy resin having 2 or more epoxy groups per l molecule react with 0.9-1.1 chemical equivalent of a carboxyl group of an unsaturated monobasic acid in the presence of an esterification catalyst at 80-130 deg.C. A polyhydric compound such as a glycol and a monomer reactive with a acid group such as a multifunctional (meth) acrylate, an monomer having a epoxy group, a monomer having an aziridinyl group are subjected to emulsion polymerization in the presence of a polymer emulsifier such as a water-soluble or water-dispersing polymer having an acid value of not less than 200 and an alkyl end group to obtain (B) fine particles of a polymer with a Tg of not more than 20 deg.C and particle sizes of 0.1-100μm. 100 pts.wt. (A) component, 1-50 pts.wt. (B) component 0.5-30 pts.wt. (C) photopolymerization initiator, and 5-100 pts.wt. (D) diluent monomer are blended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable liquid solder resist ink composition suitable for a solder resist for producing a printed wiring board, an electroless plating resist, an insulating layer of a build-up printed wiring board and the like. More specifically, it relates to a photocurable liquid solder resist ink composition capable of forming a coating film having high photosensitivity and capable of maintaining excellent adhesion and chemical resistance even when subjected to heat history after pattern formation. It is a thing.

[0002]

2. Description of the Related Art In recent years, with the increase in the density of ICs and VLSIs,
Printed circuit boards are becoming higher density and finer patterns, and it has become necessary to reduce the circuit width and circuit spacing. With the progress of higher density and finer pattern, the mainstream of solder resist on printed wiring board is
The development-oriented resist applying the principle of the photographic method is shifting to the development-oriented resist, and a liquid-development-type resist whose coating method is not particularly limited is in the spotlight. Since the organic solvent development type is not preferred in terms of environmental measures, the alkali development type that can be developed with a dilute weak alkaline aqueous solution is mainly used, and the epoxy (meth) acrylic acid obtained by reacting an epoxy resin with (meth) acrylic acid is used. ) A carboxyl group-containing epoxy (meth) acrylate in which a carboxyl group is introduced by reacting an acid anhydride with acrylate is known as an alkali developing type photocurable resin (for example, JP-A-61-2438).
69 and JP-A-63-258975).

In the pattern forming method using a liquid developing type resist, first, a resist is applied on a printed wiring board and dried by heating to form a coating film, and then a film for pattern formation is pressure-bonded to the coating film and exposed. Then, a series of steps of developing is adopted. In addition, in the above steps or in the subsequent steps, in order to improve the chemical resistance and electrical characteristics of the coating film, the crosslinking reaction may be accelerated by further irradiating with ultraviolet rays or heating.

[0004]

However, IC, super L
The demands for high density of SI, miniaturization of printed wiring board and fine patterning are unavoidable, and studies are being made from various points regarding mounting technology or solder resist. Regarding mounting technology,
For example, surface mounting technology and multi-pin packaging technology are being put to practical use one after another. On the other hand, for solder resist, it is required that the resist film does not change even after being exposed to a high temperature for a long time, especially after forming a resist coating film, but satisfactory results have not been obtained yet. The resist coating film that has been subjected to high temperature conditions has a problem that volume shrinkage occurs due to thermal shock and progress of a crosslinking reaction, and a crack is generated in the coating film or peeled from the substrate.

In view of the above, the present invention has a high photosensitivity and excellent tack-free property and developability of the coating film, and further, even when a heating process under high temperature conditions is performed after forming the resist pattern, cracks in the resist layer are not generated. It is an object of the present invention to provide a high-performance photocurable liquid solder resist ink composition in which the adhesiveness of the resist layer is not deteriorated or peeled off due to generation or volume shrinkage.

[0006]

The present invention provides a photocurable liquid solder resist ink composition containing a photocurable resin as an essential component, in which polymer fine particles having a Tg of 20 ° C. or less are dispersed. It has a gist where.

The above polymer fine particles are 0.1-100 μm.
Having an average particle diameter of m, fine particles of (meth) acrylic acid ester polymer, and having a crosslinked structure provide a resist that does not cause defects even when exposed to high temperature conditions after forming a coating film. And each is a preferred embodiment of the present invention. Further, the photocurable resin is obtained by reacting an epoxy resin having two or more epoxy groups in one molecule with unsaturated monohydrochloric acid, and particularly three or more (meth) in one molecule. It preferably has an acryloyl group. The photocurable resin having three or more (meth) acryloyl groups in one molecule may be synthesized by using a novolac type epoxy resin as the raw material epoxy resin, and has heat resistance, chemical resistance, and electrical characteristics. A coating film satisfying various physical properties such as is formed. It is also a preferable embodiment that the photocurable resin has a high molecular weight by the reaction with the chain extender before or after the reaction between the epoxy resin and the (meth) acrylic acid.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have proposed a method for solving the above-mentioned problems by using the conventional solder resist ink composition as it is, which gives very good performance in normal use, by the action of other components. The present invention has been studied and found out.

The greatest point of the present invention is that fine polymer particles are dispersed in the ink composition. After the resist is formed through the steps of light irradiation → development and the like, even if the resist layer is exposed to high-temperature conditions and thermosetting proceeds, the presence of soft polymer particles having a Tg of 20 ° C. or less causes cracks to occur. Generation and volume shrinkage are suppressed, and a decrease in adhesiveness of the resist layer is prevented.

The photocurable liquid solder resist ink composition of the present invention comprises a photocurable resin and polymer fine particles as essential components. The polymer fine particles, which is the point of the present invention, will be described first.

In the present invention, the Tg of the polymer constituting the polymer fine particles must be 20 ° C. or less. If the Tg exceeds 20 ° C., the polymer fine particles themselves become hard, and the effect of suppressing the volume shrinkage and the generation of cracks in the resist layer after photocuring does not appear. Incidentally, the polymer fine particles referred to in the present invention refers to fine particles when the polymer is dispersed in a fine particle state in the solder resist ink composition, and islands in a sea-island structure due to phase separation in an incompatible system, so-called microscopic. Domains are also included in the “polymer fine particles” of the present invention.

The kind of polymer constituting the polymer particles is not particularly limited as long as it satisfies the above Tg condition, and natural rubber; butadiene rubber (polybutadiene, NBR, SBR, etc.), isoprene rubber (IR, butyl rubber). Etc.), synthetic rubbers such as chloroprene rubber, or vulcanized products thereof; polyorganosiloxanes; esterification products of linear or branched aliphatic or alicyclic alcohols having 1 to 18 carbon atoms and (meth) acrylic acid. Is (meta)
Examples thereof include (meth) acrylic acid ester-based polymers mainly containing acrylic acid ester [including a copolymer of (meth) acrylic acid ester and "other monomer"]. Further, a rubber modified with an acid group such as a carboxyl group, a known unsaturated carboxylic acid such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, or the like, ethyl (2-methacrylic acid) 2-sulfonate, styrenesulfonic acid Also, (meth) acrylic acid ester-based polymer fine particles obtained by copolymerizing an acid group-containing monomer such as vinyl sulfonic acid with a (meth) acrylic acid ester can be used.

Examples of the "other monomer" for constituting the (meth) acrylic acid ester-based polymer fine particles include styrene-based monomers such as styrene, vinyltoluene and α-methylstyrene, (meth) acrylamide, N-.
Such as (meth) acrylamide monomers such as monoalkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide, hydroxyalkyl (meth) acrylate, monoesters of (meth) acrylic acid with polypropylene glycol or polyethylene glycol, etc. A hydroxyl group-containing (meth) acrylic acid ester-based monomer, vinyl acetate, (meth) acrylonitrile, or the like can be used. Any of these monomers is used after being adjusted so that the Tg of the polymer constituting the fine particles is 20 ° C. or less.

The fine polymer particles of the present invention preferably have a crosslinked structure. The introduction of the crosslinked structure into the polymer fine particles is effective in facilitating the handling of the polymer fine particles easily sticking and aggregating because of their relatively low Tg, and improving the moisture resistance and chemical resistance of the resist layer. Further, it also has an effect of preventing the polymer fine particles from swelling by a photocurable diluting monomer or a diluting solvent added to the ink composition as needed.

In the case of (meth) acrylic acid ester-based polymer particles, in order to introduce a crosslinked structure, a polyfunctional (meth) ester which is an ester of a polyhydroxy compound such as glycol and two or more (meth) acrylic acids is used. Acrylic ester, allyl (meth) acrylate, divinylbenzene, and polyfunctional monomers such as diallyl phthalate are copolymerized, epoxy group-containing monomers such as glycidyl (meth) acrylate, (meth) acryloylaziridine, (meth)
Aziridinyl group-containing monomers such as acryloyloxyethylaziridine, oxazolinyl group-containing monomers such as 2-isopropenyl-2-oxazoline, and other monomers having reactivity with acid groups are copolymerized to crosslink with acid groups in polymer particles. A method of causing a reaction can be adopted.

These cross-linking structure-introducing monomers are preferably copolymerized in an amount of 10% by weight or less based on all monomer components. It is an essential requirement that the polymer fine particles of the present invention have a Tg of 20 ° C. or less.
Is more than 20 ° C., or does not show Tg substantially, and the resist layer does not exhibit crack prevention and volume shrinkage prevention effects, which is not preferable.

The method for producing polymer fine particles is not particularly limited, but an emulsion polymerization method is recommended because a fine particle polymer can be easily obtained. The emulsion polymerization method is not particularly limited, and a batch mixing polymerization method, a monomer dropping method, a pre-emulsion method, a seed polymerization method, a multi-step polymerization method (core shell), etc. can be adopted.
When the (meth) acrylic acid ester-based polymer is produced by emulsion polymerization, a known emulsifier may be used,
Polymeric emulsifiers such as those disclosed in JP-A-5-25366 can also be used. This polymer emulsifier is
Water-soluble or water-dispersible terminal alkyl group having an acid value of 200 or more, which is mainly composed of an unsaturated carboxylic acid such as (meth) acrylic acid, crotonic acid, maleic acid or fumaric acid and an alkyl mercaptan having 6 to 18 carbon atoms It is a polymer or a salt thereof. Other than unsaturated carboxylic acid and alkyl mercaptan, (meth) acrylic acid ester-based monomer, styrene-based monomer, (meth) acrylamide-based monomer, etc., which are exemplified as the monomer that can be used to form the polymer particles, can be used. From the viewpoint of emulsifying ability, it is preferable to appropriately select the amount of mercaptan so as to have a molecular weight of 300 to 7,000.

When this emulsifier is used, if a monomer having reactivity with the unsaturated carboxylic acid in the emulsifier is used as a part of the polymer fine particle-constituting monomer, adverse effects of the emulsifier (decrease in moisture resistance and resistance to resistance in the resist layer) can be obtained. The deterioration of chemical properties) can be prevented as much as possible, and as such a monomer, a monomer having reactivity with the above-mentioned acid group, that is, an epoxy group-containing monomer such as glycidyl (meth) acrylate, (meth) ) Acryloyl aziridine,
Examples thereof include aziridinyl group-containing monomers such as (meth) acryloyloxyethylaziridine and oxazolinyl group-containing monomers such as 2-isopropenyl-2-oxazoline.

The average particle size of the polymer fine particles used in the present invention is preferably 0.1 to 100 μm.
If it is smaller than 0.1 μm, the filling effect will not be exhibited and 100 μm
A large diameter exceeding m reduces the accuracy of the resist pattern and is not preferable.

The amount of the polymer fine particles in the solder resist ink composition is preferably in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the photocurable resin described below. If the amount is less than 1 part by weight, the effect of preventing cracking and volume shrinkage due to heat history after the resist layer is formed is not exhibited. If the amount is more than 50 parts by weight, the characteristics such as alkali developability, resolution, and heat resistance of the cured coating film are deteriorated, which is not preferable.

The method of blending the polymer fine particles into the solder resist ink composition is not particularly limited, but a diluent is mixed with a photo-curable resin described below or an epoxy resin which is a starting material of the photo-curable resin. It is recommended that the emulsion is directly added to the above and water is removed under normal pressure or reduced pressure. A diluent that can be azeotroped with water may be used.

Next, components other than the polymer fine particles in the solder resist ink composition will be described. The type of the photo-curable resin is not particularly limited, but a photo-radical polymerizable oligomer so-called epoxy acrylate obtained by reacting an epoxy resin having two or more epoxy groups in one molecule with an unsaturated monobasic acid Use of is recommended. Various types of epoxy acrylates are known, such as the type of epoxy resin, for example, the molecular weight and epoxy equivalent, the amount of (meth) acryloyl group determined by the amount of unsaturated monobasic acid to be reacted, and any epoxy acrylate is known in the present invention. Can also be used.

As the starting epoxy resin, bisphenol type epoxy resin; biphenyl type epoxy resin;
Alicyclic epoxy resin; polyfunctional glycidylamine resin such as tetraglycidylaminodiphenylmethane; polyfunctional glycidyl ether resin such as tetraphenylglycidyl etherethane; phenol novolac type epoxy resin and cresol novolac type epoxy resin; phenol,
Reaction products of polychlorophenol compounds and epichlorohydrin obtained by condensation reaction of phenols or naphthols such as o-cresol and m-cresol with aromatic aldehydes having phenolic hydroxyl groups; phenols and divinylbenzene or dicyclopentadiene And the like, a reaction product of a polyhydric phenol obtained by an addition reaction with a diolefin compound and epichlorohydrin; a product obtained by epoxidizing a ring-opening polymerization product of 4-vinylcyclohexene-1-oxide with a peracid; and the like. Further, a chain-extended product obtained by reacting each of these epoxy resins with a chain extender such as a polybasic acid, a polyhydric phenol compound, a polyfunctional amino compound or a polyvalent thiol can also be used.

The unsaturated monobasic acid for introducing a photopolymerizable (meth) acryloyl group into the photocurable resin by reacting with the epoxy resin is one carboxyl group and one or more (meth) ) A monobasic acid having an acryloyl group, specifically acrylic acid, methacrylic acid, and a polyfunctional (meth) acrylate having one hydroxyl group and two or more (meth) acryloyl groups in one molecule. And a carboxyl group-containing polyfunctional (meth) acrylate which is a reaction product of a dibasic acid anhydride among the polybasic acid anhydrides described below.

The reaction between the epoxy resin and the unsaturated monobasic acid is carried out according to a known method, and usually one carboxyl group in the unsaturated monobasic acid is 0.9 to 1 chemical equivalent of the epoxy group in the epoxy resin. 1.1 Raw materials are charged so as to have a chemical equivalent, and as an esterification catalyst, for example, a tertiary amine such as triethylamine, a quaternary ammonium salt such as triethylbenzylammonium chloride, an imidazole compound such as 2-ethyl-4methylimidazole, Using a phosphorus compound such as triphenylphosphine, an organic acid or an inorganic salt of a metal, a chelate compound or the like, in the presence or absence of a diluent described below, in the presence of a polymerization inhibitor such as hydroquinone or oxygen, the amount of 80 to 130 By carrying out at a temperature of ° C, an epoxy (meth) acrylate which is a photocurable resin can be obtained.

Further, by reacting the hydroxyl group in the epoxy (meth) acrylate with the polybasic acid anhydride, a photocurable resin capable of developing an alkali can be obtained. Examples of polybasic acid anhydrides include phthalic anhydride, succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride and methylendomethylene. Tetrahydrophthalic anhydride,
Examples thereof include dibasic acid anhydrides such as tetrabromophthalic anhydride and trimellitic acid, and aliphatic or aromatic tetrabasic acid dianhydrides. Of these, one kind or two or more kinds can be used.

The amount of the polybasic acid anhydride to be used is 0.1 to 1.1 chemical equivalents to 1 chemical equivalent of the hydroxyl group in the epoxy (meth) acrylate, and the reaction condition is the presence of a diluent. It is carried out at 50 to 130 ° C. in the presence or absence of a polymerization inhibitor such as hydroquinone or oxygen in the presence or absence of it. At this time, if necessary, a tertiary amine such as triethylamine, or a tertiary amine such as triethylbenzylammonium chloride
A primary ammonium salt, a chloride salt or bromide salt of a metal such as lithium, zirconium, potassium, sodium, tin, zinc or lead, or a hydrate thereof may be added as a catalyst.

By the above reaction, an alkali developing type photocurable resin having a (meth) acryloyl group and a carboxyl group is obtained. This resin itself can be used as a photocurable resin which is an essential component of the composition of the present invention, but in order to improve the tack-free property before light irradiation and the coating properties such as adhesion, a chain extender is used. It is preferable to react to obtain a photocurable resin having a higher molecular weight.

In particular, the photocurable resin of the present invention has heat resistance,
A resin having three or more (meth) acryloyl groups in one molecule is preferable from the viewpoint of forming a cured coating film having excellent physical properties such as chemical resistance and electrical properties. Such a resin is
By using a trifunctional or higher functional epoxy resin such as a novolac type epoxy resin as the starting epoxy resin or a polyfunctional (meth) acrylate having two or more (meth) acryloyl groups as the unsaturated monobasic acid. Obtainable. In addition, even with a bifunctional epoxy resin such as a bisphenol type epoxy resin, by reacting a diisocyanate compound with a hydroxyl group generated after a reaction with an unsaturated monobasic acid (chain extension), it is tetrafunctional. The above resins can be obtained. Furthermore, by using a carboxyl group introduced by the reaction of an epoxy (meth) acrylate and a polybasic acid anhydride, and reacting this with a bifunctional epoxy resin to extend the chain, 3 units in one molecule are similarly obtained. It is possible to obtain a resin having one or more (meth) acryloyl groups.

The ink composition for a solder resist of the present invention preferably contains a photopolymerization initiator and a diluent in addition to the above essential constituents. As the photopolymerization initiator, known ones can be used, and specifically, benzoin and its alkyl ethers such as benzoin, benzoin methyl ether and benzoin ethyl ether; acetophenone,
2,2-dimethoxy-2-phenylacetophenone,
Acetophenones such as 1,1-dichloroacetophenone and 4- (1-t-butyldioxy-1-methylethyl) acetophenone; 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1
-Anthraquinones such as chloroanthraquinone; 2,4
Thioxanthones such as dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, 4
Benzophenones such as-(1-t-butyldioxy-1-methylethyl) benzophenone and 3,3 ', 4,4'-tetrakis (t-butyldioxycarbonyl) benzophenone; 2-methyl-1- [4- ( Methylthio) phenyl] -2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; acylphosphine oxides, xanthones and the like.

These photopolymerization initiators are used as one kind or as a mixture of two or more kinds, and preferably 0.5 to 30 parts by weight based on 100 parts by weight of the photocurable resin. When the amount of the photopolymerization initiator is less than 0.5 parts by weight, the light irradiation time must be increased or the polymerization is difficult to occur even if the light irradiation is performed, so that an appropriate surface hardness can be obtained. Disappear. Further, even if the amount of the photopolymerization initiator exceeds 30 parts by weight, there is no merit of using a large amount.

As the diluent that can be used in the solder resist ink composition, a solvent or a diluting monomer that can participate in the photopolymerization reaction can be used alone or in combination of two or more. 5 parts by weight
It is preferable to blend ˜500 parts by weight according to the optimum viscosity of each coating method. Particularly when the diluting monomer is used alone or as a diluent, it is preferable from the viewpoint of physical properties that the diluting monomer is blended in an amount of 5 to 100 parts by weight with respect to 100 parts by weight of the photosensitive resin.

Examples of the solvent include hydrocarbons such as toluene and xylene; cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; esters such as cellosolve acetate and carbitol acetate; methyl isobutyl ketone, Examples thereof include ketones such as methyl ethyl ketone; ethers such as diethylene glycol dimethyl ether. Examples of the diluting monomer include diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate,
β-hydroxyethyl (meth) acrylate, (2-oxo-1,3-dioxolan-4-yl) -methyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth)
Examples thereof include acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acrylate of tris (hydroxyethyl) isocyanurate, and the like.

The solder resist ink composition of the present invention contains the above-described photocurable resin and polymer fine particles as essential components, and preferably contains a photopolymerization initiator and a diluent, but it is further required. Correspondingly, fillers such as talc, clay, barium sulfate, coloring pigments, defoamers,
Coupling agents, leveling agents, etc., novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, alicyclic epoxy resins, epoxy resins such as triglycidyl isocyanurate, and epoxy curing agents such as dicyandiamide, imidazole compounds Etc. can also be added.

The photocurable resin that can be used in the present invention can be alkali-developed because it can be alkali-developed because the portion not exposed to light is dissolved in the alkaline aqueous solution. Examples of the alkali that can be used for development include alkali metal compounds such as sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide; alkaline earth metal compounds such as calcium hydroxide; ammonia; monomethylamine, dimethylamine, trimethylamine, mono Ethylamine,
Diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine,
Examples thereof include water-soluble organic amines such as diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, dimethylaminoethyl methacrylate, and polyethyleneimine, and one or more of these can be used.

[0036]

The present invention will be described in more detail with reference to the following examples, but the following examples do not limit the present invention.
Modifications and alterations that do not depart from the spirit described below are all included in the technical scope of the present invention. The parts and percentages in the examples are on a weight basis.

Example 1 <(Meth) acrylic ester polymer fine particles [1]
Synthesis> In a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel was charged 180 parts of isopropyl alcohol, and the temperature was raised to 81 ° C. with nitrogen blowing, and the mixture was refluxed for 10 minutes. In this flask, 53.6 parts of acrylic acid, 16.5 parts of lauryl methacrylate, 91 parts of Bremmer PE-200 (polyethylene glycol monomethacrylate ester manufactured by NOF CORPORATION), 13.7 parts of n-dodecyl mercaptan and 2, A mixture of 0.4 parts of 2'-azobisisobutyronitrile was added dropwise over 2 hours. After completion of the dropping, aging is further carried out for 1 hour under reflux,
A solution of polymer emulsifier with a non-volatile content of 49.1% was obtained.

Next, a stirrer, a reflux condenser, a nitrogen introducing pipe,
A separate flask equipped with a thermometer and a dropping funnel was charged with 63 parts of ion-exchanged water, and the temperature was raised to 70 ° C. while blowing nitrogen gas. 85 parts of ethyl acrylate, 10 parts of methyl methacrylate, 5 parts of glycidyl methacrylate, 4.1 parts of a solution of a polymer emulsifier, 0.5 parts of 28% ammonia water, and 36 parts of ion-exchanged water were mixed well and stirred thoroughly, A pre-emulsion emulsified in was prepared and charged in the dropping funnel of the flask.

After injecting 8 parts of a 5% aqueous solution of 4,4'-azobis (4-cyanopentanoic acid) neutralized ammonium salt into the flask, the above pre-emulsion was added dropwise from the dropping funnel over 3.5 hours. The temperature was maintained at 70 to 75 ° C during the dropping. After the dropping was completed, the pre-emulsion remaining in the funnel was washed with 10 parts of ion-exchanged water, the washing solution was placed in the flask, and the stirring was continued for 2 hours to complete the polymerization. An emulsion of (meth) acrylic acid ester-based polymer fine particles [1] having a nonvolatile content of 46.0% was obtained. A part of the emulsion was sampled, water was evaporated, and the Tg of the polymer was measured by a differential scanning calorimeter to be -8 ° C.

<Production of Ink Composition for Solder Resist> Cresol novolac type epoxy resin YDCN-7
03 (Toto Kasei, epoxy equivalent 200) 100 parts,
Add 80 parts of ethyl carbitol acetate and stir 1
It was heated and dissolved at 20 ° C. After cooling to 60 ° C., 43.48 parts of the above-mentioned polymer fine particle [1] emulsion was added, and the temperature was raised to 130 ° C. with stirring to completely remove water. Then, 36.9 parts of acrylic acid, 0.14 parts of chromium (II) chloride hexahydrate and 0.11 of methylhydroquinone.
Parts were added and reacted at 110 ° C. for 3 hours. The acid value of the reaction product became 3.0, and the introduction of an acryloyl group was confirmed.
Next, 45.6 parts of tetrahydrophthalic anhydride, 29 parts of ethyl carbitol acetate and 0.14 parts of anhydrous lithium chloride were added, and the mixture was reacted at 100 ° C. for 3 hours. 65% of polymer fine particles [1] and photocurable resin having an acid value of 90
Mixed composition with ethyl carbitol acetate containing (A
-1) was obtained.

Example 2 To 100 parts of the same epoxy resin (cresol novolac type epoxy resin YDCN-703) as in Example 1 was added 80 parts of ethyl carbitol acetate, and the mixture was stirred at 120 ° C.
It was heated and dissolved in. Then, 36.9 parts of acrylic acid, 0.14 part of chromium (II) chloride hexahydrate and 0.11 part of methylhydroquinone were added, and the mixture was reacted at 110 ° C. for 3 hours. The acid value of the reaction product was 3.3, and the introduction of an acryloyl group was confirmed. After cooling to 60 ° C., an emulsion 43.48 of polymer fine particles [1] synthesized in Example 1
Parts were added and the temperature was raised to 115 ° C. with stirring to completely remove water.

Subsequently, tetrahydrophthalic anhydride 45.
6 parts, 29 parts of ethyl carbitol acetate and 0.14 parts of anhydrous lithium chloride were added, and the mixture was reacted at 100 ° C. for 3 hours. A mixed composition (A-2) of polymer fine particles [1] and ethyl carbitol acetate containing 65% of a photocurable resin having an acid value of 90 was obtained.

Example 3 To 100 parts of the same epoxy resin as in Example 1 was added 80 parts of ethyl carbitol acetate, and the mixture was heated and dissolved at 120 ° C. with stirring. Then, 36.9 parts of acrylic acid, 0.14 part of chromium (II) chloride hexahydrate and 0.11 part of methylhydroquinone were added, and the mixture was reacted at 110 ° C. for 3 hours. The acid value of the reaction product was 3.3, and the introduction of an acryloyl group was confirmed. Next, tetrahydrophthalic anhydride 45.6
Parts, 29 parts of ethyl carbitol acetate and 0.14 parts of anhydrous lithium chloride were added and reacted at 100 ° C. for 3 hours. After cooling to 60 ° C., 43.48 parts of an emulsion of polymer fine particles [1] synthesized in Example 1 was added,
The temperature was raised to 115 ° C. with stirring to completely remove water, and 65% of the polymer fine particles [1] and the photocurable resin having an acid value of 91 were added.
Mixed composition with ethyl carbitol acetate containing (A
-3) was obtained.

Example 4 <(Meth) acrylic ester type polymer fine particles [2]
Synthesis> In the process of synthesizing the polymer particles of Example 1, instead of the polymer emulsifier, Hitenol N08
Emulsion polymerization was performed in the same manner as in Example 1 except that (Daiichi Kogyo Seiyaku Co., Ltd., ammonium phenyl polyethylene oxide sulfonate) was used to obtain a nonvolatile content of 4
An emulsion of 6.5% (meth) acrylate polymer fine particles [2] was obtained. A part of the emulsion was collected, water was evaporated, and the Tg of the polymer was measured by a differential scanning calorimeter to be -10 ° C.

To 100 parts of the same epoxy resin as in Example 1,
Add 80 parts of ethyl carbitol acetate and stir 1
It was heated and dissolved at 20 ° C. After cooling to 60 ° C., 43.01 parts of the emulsion of polymer fine particles [2] was added, and the temperature was raised to 130 ° C. with stirring to completely remove water. Then, 36.9 parts of acrylic acid, 0.14 parts of chromium (II) chloride hexahydrate and 0.11 of methylhydroquinone.
Parts were added and reacted at 110 ° C. for 3 hours. The acid value of the reaction product became 3.0, and the introduction of an acryloyl group was confirmed.
Next, 45.6 parts of tetrahydrophthalic anhydride, 29 parts of ethyl carbitol acetate and 0.14 parts of anhydrous lithium chloride were added and the reaction was carried out at 100 ° C. for 3 hours. 65% of polymer fine particles [2] and a photocurable resin having an acid value of 89
Mixed composition with ethyl carbitol acetate containing (A
-4) was obtained.

Example 5 To 100 parts of bisphenol A type epoxy resin GY-250 (manufactured by Ciba-Geigy, epoxy equivalent 185), 80 parts of ethyl carbitol acetate was added, and the mixture was stirred at 60 ° C.
The temperature was raised to a uniform solution. After adding 43.48 parts of the emulsion of polymer fine particles [1] synthesized in Example 1, the temperature was raised to 130 ° C. with stirring to completely remove water. Then, 38.9 parts of acrylic acid, 0.14 part of chromium (II) chloride hexahydrate and 0.12 of methylhydroquinone.
Parts were added and reacted at 110 ° C. for 3 hours. The reaction is cooled to 100 ° C. and tetrahydrophthalic anhydride 82.
100 parts by adding 2 parts and 0.14 parts of anhydrous lithium chloride
The reaction was performed at 10 ° C. for 10 hours. Add 50 parts of epoxy resin GY-250 and react at 110 ° C. for 5 hours.
Tetrahydrophthalic anhydride (39.6 parts) and ethylcarbitol acetate (98.1 parts) were added, and the mixture was reacted at 100 ° C. for 3 hours. A mixed composition (A-5) of polymer fine particles [1] and ethyl carbitol acetate containing 65% of a photocurable resin having an acid value of 93 was obtained.

Comparative Example 1 To 100 parts of the same epoxy resin as in Example 1 (cresol novolac type epoxy resin YDCN-703) was added 80 parts of ethyl carbitol acetate, and the mixture was heated and dissolved at 120 ° C. with stirring. Next, 36.9 parts of acrylic acid, 0.14 parts of chromium (II) chloride hexahydrate and 0.11 parts of methylhydroquinone were added and reacted at 110 ° C. for 3 hours to give an acid value of the reaction product of 3.3. I confirmed that. Next, 45.6 parts of tetrahydrophthalic anhydride, 18.3 parts of ethyl carbitol acetate and 0.14 of anhydrous lithium chloride.
Parts were added and reacted at 100 ° C. for 3 hours. Mixed composition with ethyl carbitol acetate containing 65% of a photocurable resin having an acid value of 95, which does not contain polymer particles (A-6)
was gotten.

Comparative Example 2 To 100 parts of the same epoxy resin as in Example 5 (bisphenol A type epoxy resin GY-250), 80 parts of ethyl carbitol acetate was added, and the temperature was raised to 110 ° C. with stirring, and acrylic acid 38. 9 parts, 0.14 parts of chromium (II) chloride hexahydrate and 0.12 parts of methylhydroquinone were added and reacted for 3 hours. The reaction product was cooled to 100 ° C., 82.2 parts of tetrahydrophthalic anhydride and 0.14 part of anhydrous lithium chloride were added, and the reaction was carried out at 100 ° C. for 10 hours. Next, 50 parts of epoxy resin GY-250 was added and reacted at 110 ° C. for 5 hours, 33.1 parts of tetrahydrophthalic anhydride and 83.8 parts of ethylcarbitol acetate were further added, and reacted at 100 ° C. for 3 hours. Let 6 photocurable resin with acid value of 92, which does not contain polymer particles
A mixed composition (A-7) with 5% ethyl carbitol acetate was obtained.

Examples 6 to 10 and Comparative Examples 3 to 5 Table 1 shows the mixed compositions (A-1) to (A-7) obtained in Examples 1 to 5 and Comparative Examples 1 and 2. The composition was adjusted to obtain a solder resist ink composition. Table 2 shows the results evaluated by the following methods.

[Evaluation of developability] Degreased and washed thickness 1.6
An ink composition for a solder resist having a thickness of 20 to 30 μm is coated on a copper clad laminate having a thickness of 20 mm and the temperature is set to 80 ° C. for a predetermined time (30, 40, 50, 60) in a hot air circulation drying oven.
Min) dried to obtain a coating film. Next, development was carried out for 80 seconds at a pressure of 2.1 kg / cm ² at 30 ° C. using a 1% Na ₂ CO ₃ aqueous solution, and the residual resin was visually evaluated. Good: No resist remains on the copper surface Poor: A considerable amount of resist remains on the copper surface

[Evaluation of Alkali Resistance] A coating film was formed in the same manner as in the evaluation of developability, and it was treated with an ultrahigh pressure mercury lamp of 1 Kw for 50 minutes.
Irradiate with a light amount of 0 mJ / cm ² , and further 30 at 150 ° C.
Heated for a minute. Then, it was immersed in a 10% aqueous sodium hydroxide solution at 20 ° C. for 20 minutes, and the state of the coating film after the immersion was visually evaluated. ◯: There is no abnormality in the appearance of the coating film ×: The coating film swells or peels off

[Evaluation of Adhesiveness] A coating film was formed in the same manner as in the evaluation of developability, and was subjected to 5 by using an ultrahigh pressure mercury lamp of 1 Kw.
After irradiating with a light amount of 00 mJ / cm ² and then heating at 150 ° C. for 30 minutes, 100 grids of 1 mm × 1 mm were cut according to the test method of JIS D-0202. Further, the sample was heated at 175 ° C. or 200 ° C. for 30 minutes, and a peeling test using an adhesive tape was performed on each sample, and the peeled state of the coating film was visually determined. ◯: No change at 100/100 Δ: 80/100 to 99/100 ×: 0/100 to 79/100

[0053]

[Table 1]

[0054]

[Table 2]

Examples of the present invention (Examples 6 to 1) using an ink composition for a solder resist containing polymer fine particles.
0) is developability, alkali resistance after heating
It is clear that the adhesiveness is excellent. However, in the comparative example in which the polymer fine particles are not blended, there is a clear difference from the example in the adhesiveness after the heating step. It is considered that this is because in the heating step after light irradiation, fine cracks and volume shrinkage occurred in the resist layer, and the adhesiveness with the substrate was lowered, and the presence of polymer fine particles can prevent these disadvantages. Was confirmed.

[0056]

EFFECT OF THE INVENTION The ink composition for a solder resist of the present invention has excellent adhesion to a substrate even in a line in which a heating step is incorporated after pattern formation by simply dispersing polymer fine particles having a Tg of 20 ° C. or less in the composition. It was possible to form a resist layer exhibiting properties. Since there is no need to change the molecular design of the photo-curable resin between the lines with and without the heating process, it has excellent tack-free properties before light irradiation, high resolution, excellent alkali developability, and adhesion. It has become possible to provide a high-performance photocurable liquid solder resist ink composition capable of forming a cured coating film having excellent heat resistance, chemical resistance, and the like.

Claims (7)

[Claims] 1. An ink composition for a solder resist containing a photocurable resin as an essential component, wherein fine particles of polymer having a Tg of 20 ° C. or less are dispersed in the composition. Ink composition for liquid solder resist. 2. Polymer fine particles are 0.1 to 100 μm.
The ink composition according to claim 1, having an average particle diameter of. 3. The ink composition according to claim 1, wherein the polymer fine particles are (meth) acrylic acid ester-based polymer fine particles. 4. The ink composition according to claim 1, wherein the fine polymer particles have a crosslinked structure. 5. The photo-curable resin is obtained by reacting an unsaturated monobasic acid with an epoxy resin having two or more epoxy groups in one molecule. Ink composition. 6. The photocurable resin has 3 or more (meth) acryloyl groups in one molecule.
The ink composition according to any one of 5 above. 7. The ink composition according to claim 6, wherein the epoxy resin which is a raw material of the photocurable resin is a novolac type epoxy resin.