JP4406262B2 - Photosensitive resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition useful for image formation.

  The photosensitive resin composition for image formation is capable of microfabrication by applying the principle of photolithography (photolithography) and can form an image by giving a cured product having excellent physical properties. It is widely used for various resist materials and printing plates. There are a solvent development type and an alkali development type in this photosensitive resin composition for image formation, but in recent years, an alkali development type that can be developed with a dilute weak alkaline aqueous solution has become mainstream from the viewpoint of environmental measures. Alkali-developable photosensitive resin compositions are also used in printed wiring board production, liquid crystal display board production, printing plate making and the like.

  When the photosensitive resin composition for image formation is used in a photolithography process as a resin composition for a liquid development type solder resist, for example, the resin composition is first applied on a substrate, and then dried by heating. A series of steps is employed in which after forming a coating film, a film for forming a pattern is attached to the coating film, exposed, and developed. In such a process, if adhesiveness remains in the coating film after drying by heating, a part of the resist adheres to the pattern forming film after peeling, and an accurate pattern cannot be reproduced. There was a problem that the forming film could not be peeled off. For this reason, tack-free property after coating film formation is an important required characteristic of a liquid development type resist.

  In addition, photosensitivity during exposure and developability after exposure are also important required characteristics. That is, in order to form a fine pattern with high reliability and good reproducibility, during development, a portion cured by exposure must not be eroded by the developer, and conversely, an unexposed portion can be promptly developed during development. Must be removed.

  Furthermore, for the cured part, characteristics related to long-term reliability such as heat resistance, water resistance, moisture resistance, etc. that can withstand high processing conditions (soldering process in the case of solder resist, etc.) are required. ing.

  Carboxyl group-containing epoxy (meth) acrylate in which a carboxyl group is introduced by reacting an acid anhydride with an epoxy (meth) acrylate obtained by reacting an epoxy resin with (meth) acrylic acid to satisfy the above characteristics to some extent. Is known (for example, Patent Documents 1 and 2). This carboxyl group-containing epoxy (meth) acrylate satisfies a balanced balance of tack-free properties, photosensitivity, and developability, and compares important properties such as heat resistance and water resistance required for cured products. Good. However, with the advancement of technology, higher level characteristics are demanded. For example, a photosensitive resin for image formation that can withstand processing under high temperature conditions is required.

If it is said epoxy (meth) acrylate, it is thought that heat resistance will be improved by introducing many double bonds into the resin skeleton using polyfunctional epoxy resin or (meth) acrylate and increasing the crosslinking density. It is done. However, since the cured coating film becomes brittle as the crosslink density increases, the epoxy (meth) acrylate photosensitive resin has a problem that it is difficult to balance heat resistance and brittleness reduction.
As a photosensitive resin capable of meeting high heat resistance requirements, a resin in which an N-substituted maleimide is introduced into a copolymer skeleton has been studied (Patent Document 3). However, in this system, too much emphasis on heat resistance may cause brittleness in the cured product or decrease in alkali developability. Further, the resin disclosed in this document is obtained by obtaining a N-substituted maleimide copolymer, followed by a double bond introduction reaction for about 24 hours, and then a carboxyl group introduction reaction for developing alkali developability. For about 3 hours, and it took a long time for production.

JP-A 61-243869 JP 63-258975 A Japanese Patent Laid-Open No. 10-139843 (page 5, page 9, etc.)

  Therefore, the present invention has an object to provide a photosensitive resin for image formation that can achieve both sensitivity at the time of exposure and alkali developability, and further provides a cured product that is excellent in heat resistance but does not develop brittleness. Raised.

The present invention that has solved the above-mentioned problems is a photosensitive resin composition that can form a coating film that can be alkali-developed, and includes an N-substituted maleimide component (A) and a hydroxyl group-containing monomer (B). Modified polymer (II) having a carboxyl group obtained by reacting a part or all of hydroxyl groups of polymer (I) obtained by radical polymerization as a component with polybasic acid anhydride (C) A modified polymer having a radical polymerizable double bond obtained by reacting a radical polymerizable monomer (D) having a functional group capable of reacting with a carboxyl group with at least a part of the carboxyl group of III) is included in the first gist.

Furthermore, the second and third aspects are that epoxy (meth) acrylate is contained, and that a compound having a functional group capable of reacting with two or more carboxyl groups is contained in one molecule, respectively. To do.

In addition , with respect to at least part of the hydroxyl groups of the polymer (I) obtained by radical polymerization using the N -substituted maleimide component (A) and the hydroxyl group-containing monomer (B) as essential components, A modified polymer (II) having a carboxyl group characterized by reacting a basic acid anhydride (C) is obtained, and at least one of a hydroxyl group and / or a carboxyl group of the carboxyl group-containing modified polymer (II) is obtained. A method for producing a modified polymer (III) having a radically polymerizable double bond, characterized in that a radically polymerizable monomer (D) having a functional group capable of reacting with these groups is reacted with a part, Is the fourth gist.

Examples of N-substituted maleimide components that can be used in the present invention include N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (4-methylphenyl) maleimide, and N- (2,6-diethylphenyl) maleimide. N- (2-chlorophenyl) maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmethylmaleimide, N- (2,4,6- Tribromophenyl) maleimide, N- [3- (triethoxysilyl) propyl] maleimide, N-octadecenylmaleimide, N-dodecenylmaleimide, N- (2-methoxyphenyl) maleimide, N- (2 , 4,6-Trichlorophenyl) maleimide, N- (4-hydroxyphenyl) Maleimide, include the N-(1-hydroxyphenyl) maleimide and the like, can be used singly or in combination of two or more thereof. Among these, N-phenylmaleimide, N- (2-methylphenyl) maleimide, N- (2,6-diethylphenyl) are advantageous in that the effect of improving heat resistance is great, the copolymerizability is good, and they are easily available. Maleimide, N-laurylmaleimide, N-cyclohexylmaleimide and the like are preferable, N-phenylmaleimide and N-cyclohexylmaleimide are more preferable, and N-phenylmaleimide is most preferable.
(B) Hydroxyl group-containing monomer The hydroxyl group-containing monomer introduces a hydroxyl group into the polymer and is converted into a carboxyl group by a reaction with a polybasic acid anhydride in a later step to provide alkali developability. It is an essential monomer component for imparting.

  Conventionally, as a polymer having a carboxyl group, for example, a copolymer obtained by copolymerizing an unsaturated monobasic acid such as (meth) acrylic acid, or a glycidyl group-containing skeleton as described in Patent Document 3 described above. A product obtained by reacting an unsaturated monobasic acid with a glycidyl group therein and ring-opening the glycidyl group with a polybasic acid anhydride is known.

  However, a product obtained by copolymerizing an unsaturated monobasic acid has a carboxyl group close to the main chain, and a product obtained by reacting a polybasic acid anhydride with a hydroxyl group formed by ring opening of a glycidyl group. Since the carboxyl group is bonded to the portion closer to the main chain than the introduced unsaturated group, there is room for improvement in alkali developability.

  On the other hand, in the present invention, a hydroxyl group is introduced at a position separated from the main chain by copolymerizing a hydroxyl group-containing monomer, and a polybasic acid anhydride is reacted with the hydroxyl group. A carboxyl group can be introduced at a position away from the substrate. As a result, even when a hydrophobic group such as an N-substituted maleimide group is present, good alkali developability can be exhibited, and both heat resistance and compatibility can be achieved.

  Examples of the hydroxyl group-containing monomer that can be used in the present invention include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. 4-hydroxymethyl (meth) acrylamide, pentaerythritol mono (meth) acrylate, dipentaerythritol mono (meth) acrylate, trimethylolpropane mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, glycerol mono (Meth) acrylate, hydroxyalkyl vinyl ethers such as 4-hydroxybutyl vinyl ether, allyl alcohol, p-hydroxystyrene, etc. are mentioned, and one or more of these are combined. It is possible to have. Among these, those having a primary alcoholic hydroxyl group are preferable and particularly preferable from the viewpoint that the reactivity with the polybasic acid anhydride is good and the generated carboxyl group is less susceptible to steric hindrance and efficiently develops developability. Those are 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth) acrylate.

  Further, a product obtained by adding alkylene oxide to the above hydroxyl group-containing monomer, “Placcel F” series (manufactured by Daicel Chemical Industries) which is a modified polycaprolactone of 2-hydroxyethyl (meth) acrylate, 1,18-octadecane Long-chain alcohols such as a reaction product of a long-chain dibasic acid such as dicarboxylic acid or 1,16- (6-ethylhexadecane) dicarboxylic acid and an epoxy group-containing monomer such as glycidyl methacrylate can be used for a cured coating film. Since flexibility can be imparted, it is particularly preferably used when such properties are required for the coating film.

  When the said polymer (I) consists of a 100 mol% structural unit, N-substituted maleimide component (A) has a preferable molar ratio of 5-80 mol%. When the content of the N-substituted maleimide component (A) is less than 5 mol%, sufficient heat resistance cannot be imparted to the cured coating film. On the other hand, if the content exceeds 80 mol%, the content of the hydroxyl group-containing monomer (B) decreases, and the amount of carboxyl groups introduced in the subsequent polybasic acid anhydride (C) reaction step becomes alkaline. It may be insufficient to develop developability. The more preferable lower limit of the N-substituted maleimide component (A) is 10 mol%, and the more preferable lower limit is 15 mol%. Moreover, a more preferable upper limit is 60 mol%, and a more preferable upper limit is 40 mol%.

  The hydroxyl group-containing monomer (B) preferably has a molar ratio of 20 to 95 mol% when the polymer (I) is composed of 100 mol% of structural units. When the content of the hydroxyl group-containing monomer (B) is less than 20 mol%, the number of carboxyl groups introduced in the subsequent polybasic acid anhydride (C) reaction step decreases, and the alkali developability becomes insufficient. There is. On the other hand, if the content exceeds 95 mol%, the content of the N-substituted maleimide component (A) decreases, and sufficient heat resistance cannot be obtained. The amount of (including)) is too large, and the water resistance of the cured coating film may be lowered. The more preferable lower limit of the hydroxyl group-containing monomer (B) is 30 mol%, and the more preferable lower limit is 40 mol%. Moreover, a more preferable upper limit is 85 mol%, and a more preferable upper limit is 75 mol%.

  When obtaining the polymer (I), another monomer component copolymerizable with the N-substituted maleimide component (A) and the hydroxyl group-containing monomer (B) may be used in combination. The copolymerizable monomer component is preferably 75 mol% or less in terms of molar ratio when the polymer (I) is composed of 100 mol% structural units, and more preferably has an upper limit of 60 mol%. A preferable upper limit is 45 mol%.

Specific examples of the copolymerizable monomer component include aromatic vinyl monomers such as styrene, α-methylstyrene, α-chlorostyrene, and vinyl toluene; vinyl ester monomers such as vinyl acetate and vinyl adipate. ; (Meth) acrylic monomers such as (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate; n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether , N-hexyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether and other alkyl vinyl ethers and corresponding alkyl vinyl (thio) ethers; monomers containing acid anhydride groups such as maleic anhydride or alcohols, amines, water etc A monomer obtained by ring-opening modification of an acid anhydride group with N-vinyl monomers such as N-vinylpyrrolidone and N-vinyloxazolidone.
The amounts charged in the polymerization of the N-substituted maleimide component (A), the hydroxyl group-containing monomer (B), and the monomer that may be used in combination are the properties of the target polymer, and In consideration of the conversion rate of each monomer (polymerization rate for conversion from monomer to polymer), each component in the polymer may be appropriately determined so as to fall within the preferred range.

  The method for obtaining the polymer (I) is not particularly limited, and a conventionally known polymerization method such as a solution polymerization method or a bulk polymerization method can be employed. Among these, a solution polymerization method is preferable because temperature control during the polymerization reaction is easy.

  The solvent for the solution polymerization is not particularly limited as long as it does not inhibit the polymerization or alter each component of the raw material monomer. Specific examples of usable solvents include hydrocarbons such as toluene and xylene; cellosolve acetate, carbitol acetate, (di) propylene glycol monomethyl ether acetate, glutaric acid (di) methyl, succinic acid (di) methyl, and adipine Acid (di) methyl, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc .; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; diethyl ether, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, And ethers such as methyl-t-butyl ether and (di) ethylene glycol dimethyl ether; amides such as N, N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide, and the like. Others can be used in combination of two or more.

  Examples of the initiator that can be used in the polymerization reaction include ordinary radical polymerization initiators. Specifically, 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile) ), Azo compounds such as 2,2′-azobis (2-methylisobutyronitrile); lauroyl peroxide, benzoyl peroxide, t-butylperoxyneodecanate, t-butylperoxypivalate, t- Organic peroxides such as butyl peroxy-2-ethylhexanoate, t-butyl peroxybenzoate, methyl ethyl ketone peroxide, dicumyl peroxide, etc. can be mentioned, and selected as appropriate according to desired reaction conditions Use it.

  The amount of the initiator used is preferably 0.001 to 5.0% by mass, more preferably 0.01 to 2.0%, based on the N-substituted maleimide component (A) used in the polymerization reaction. % By mass.

  The specific method for obtaining the polymer (I) is not particularly limited, but a method in which all components are charged at once in a solvent for polymerization, and the remaining components are put in a reaction vessel in which a part of the solvent and components are previously charged. A method of polymerization by continuous addition or sequential addition can be employed.

  There is no particular limitation on the pressure during the reaction, and the reaction may be performed under normal pressure or pressurized conditions. Regarding the temperature during the polymerization reaction, although it depends on the type and composition ratio of the raw material monomer used and the type of solvent used, it is usually preferably in the range of 20 to 150 ° C, more preferably 30 to 120 ° C. .

During the polymerization reaction, it is preferable to set the amount of the solvent and each monomer component so that the final solid content concentration of the polymer solution is 10 to 70% by mass. If this final solid content concentration is less than 10% by mass, productivity is lowered, which is not preferable. On the other hand, when the final solid content concentration exceeds 70% by mass, the viscosity of the polymerization solution may increase even in the case of solution polymerization, and the polymerization conversion rate may not increase. A more preferable final solid content concentration is 20 to 65% by mass, and further preferably 30 to 60% by mass.
Considering characteristics as a resin composition, alkali developability, cured coating film properties, heat resistance, etc., the weight average molecular weight Mw of the polymer (I) is a value measured by gel permeation chromatography (GPC). As a polystyrene conversion value, 1,000 to 200,000 is preferable. If Mw is less than 1,000, tack-free property during coating formation by heat drying or heat resistance of the cured coating film may be insufficient. On the other hand, when Mw exceeds 200,000, alkali developability may be deteriorated. A more preferred lower limit of Mw is 3,000, and a more preferred lower limit is 5,000. A more preferred upper limit is 100,000, and a more preferred upper limit is 50,000.

  In order to adjust the molecular weight within this range, a chain transfer agent may be used during the polymerization reaction, if necessary. Usable chain transfer agents are not particularly limited as long as they do not adversely affect each monomer component used in the polymerization, and thiol compounds are usually used. Specifically, alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan; aryl mercaptans such as thiophenol; mercapto group-containing aliphatic carboxylic acids such as mercaptopropionic acid and methyl mercaptopropionate and the like Ester etc. are mentioned as a preferable thing. The amount of chain transfer agent used is not particularly limited, and may be appropriately adjusted so as to obtain a polymer (I) having a desired molecular weight. It is used in the range of 0.001 to 1.0 (molar ratio) with respect to the number.

  After obtaining the polymer (I), subsequently, the polybasic acid anhydride (C) is subjected to addition reaction with the hydroxyl group of the polymer (I) to obtain a modified polymer (II). By this addition (modification) reaction, a carboxyl group can be introduced and alkali developability can be imparted. Therefore, a resin composition configured with a radical polymerizable compound such as epoxy (meth) acrylate described later is used for alkali development type image forming. It is useful as a photosensitive resin composition.

Examples of the polybasic acid anhydride (C) include phthalic anhydride, succinic anhydride, octenyl succinic anhydride, pentadodecenyl succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3 , 6-Endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, tetrabromophthalic anhydride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and itaconic anhydride or maleic anhydride Dibasic acid anhydride such as a reaction product with; trimellitic anhydride; biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, diphenyl ether tetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclo Pentanetetra Examples thereof include aliphatic or aromatic tetrabasic acid dianhydrides such as rubonic acid dianhydride, pyromellitic anhydride and benzophenone tetracarboxylic dianhydride, and one or more of these can be used. .
The solvent for the modification is not particularly limited, and any of the solvents described above can be used as a solvent that can be used as a polymerization solvent. Industrially, it is convenient to carry out the modification reaction by adding the polybasic acid anhydride (C) to the reaction solution following the solution polymerization.

  A catalyst may be used in the modification reaction as necessary. Specific catalysts include tertiary amines such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, imidazole compounds such as 2-ethyl-4-methylimidazole, phosphorus such as triphenylphosphine and tetraphenylphosphonium bromide. Examples thereof include a compound, a carboxylic acid metal salt such as lithium acetate, and an inorganic metal salt such as lithium carbonate.

The polybasic acid anhydride (C) is such that the acid anhydride group in the polybasic acid anhydride is 0.1 to 1.1 mol per one chemical equivalent of the hydroxyl group in the polymer (I). It is preferable to make it react, More preferably, it is 0.2-0.9 mol. In order to develop good alkali developability even with a weak alkaline aqueous solution, the acid value of the modified polymer (II) is preferably 30 mgKOH / g or more, and a more preferred lower limit is 50 mgKOH / g. Moreover, a preferable upper limit is 150 mgKOH / g, and a more preferable upper limit is 120 mgKOH / g. About reaction temperature, Preferably it is 60-150 degreeC, More preferably, it is 80-120 degreeC.
In the present invention, a resin composition constituted with a modified polymer (II) and a radical polymerizable compound such as epoxy (meth) acrylate described later can be used as an alkali developing type photosensitive resin composition for image formation. Is a radically polymerizable double bond obtained by reacting the hydroxyl group and / or carboxyl group of the modified polymer (II) with a monomer (D) having a functional group capable of reacting with these groups It is also possible to use a modified polymer (III) having

Examples of the functional group capable of reacting with a hydroxyl group and / or a carboxyl group include an isocyanate group, a vinyl ether group, an epoxy group, an oxazoline group, an aziridine group, and an oxetanyl group. Specific examples of the monomer (D) include Isocyanatoethyl (meth) acrylate, (meth) acrylic acid 2- (vinyloxyethoxy) ethyl, glycidyl (meth) acrylate, allyl glycidyl ether, 2-isopropenyl-2-oxazoline, N- (meth) acryloylaziridine and the like Of these, one or more of them can be used.
When the hydroxyl group and the monomer (D) are reacted, the reaction can be performed at any stage before or after the reaction with the polybasic acid anhydride (C). The reaction conditions between the hydroxyl group and / or carboxyl group and the monomer (D) may be determined by appropriately selecting the catalyst and reaction temperature for each functional group by a known method.
The amount of the monomer (D) used relative to the hydroxyl group and / or carboxyl group is such that the functional group capable of reacting with these in the monomer (D) is 0.9 mol or less, more preferably 0.8 mol or less. It is preferable to make it react so that.

  In addition, when the monomer (D) is reacted with the carboxyl group of the modified polymer (II), the carboxyl group is consumed, and thus the modified polymer (III) having a radical polymerizable double bond is obtained. ) Of the modified polymer (II) and the monomer (D) so that the acid value is 30 mgKOH / g or more (more preferably 50 mgKOH / g or more) and 150 mgKOH / g or less (more preferably 120 mgKOH / g or less). ) Is preferably adjusted.

The modified polymer (III) having a radical polymerizable double bond thus obtained has both a carboxyl group and a radical polymerizable double bond. It can also be used as a photosensitive resin.
In the present invention, a modified polymer (II) and / or a modified polymer (III) having a radical polymerizable double bond and a known radical polymerizable compound are mixed to obtain an alkali developing type photosensitive resin composition for image formation. Use as a product. Such radically polymerizable compounds include radically polymerizable resins and radically polymerizable monomers. As the radical polymerizable resin, unsaturated polyester, epoxy acrylate, urethane acrylate, polyester acrylate, or the like can be used. When these radical polymerizable resins are used, in order to effectively exhibit the heat resistance improving effect derived from the modified polymer (II) or (III) used as a component of the photosensitive resin composition of the present invention, When the amount (total amount of the modified polymer solid content of the present invention and the radical polymerizable resin solid content) is 100% by mass, the radical polymerizable resin is preferably used at 80% by mass or less. A more preferred upper limit is 70% by mass, and a still more preferred upper limit is 60% by mass.

  Among the above radical polymerizable resins, epoxy acrylate, in particular, has good photopolymerizability, is effective in improving the properties of the resulting cured product, and is blendable with modified polymers (II) and (III). Therefore, it can be suitably used as the photosensitive resin component of the photosensitive resin composition of the present invention. As the epoxy acrylate, a reaction product of a known epoxy resin having two or more epoxy groups in one molecule and an unsaturated monobasic acid (such as (meth) acrylic acid) can be used as it is. A preferable epoxy resin is an epoxy resin having three or more epoxy groups in one molecule, more preferably a novolac type epoxy resin, and further, when a novolac type epoxy resin having a softening point of 75 ° C. or higher is used, the resin is dried by heating. It is preferable in terms of good tack-free property during coating film formation. Moreover, it is also possible to use a carboxyl group-containing epoxy acrylate obtained by addition reaction of the above-mentioned polybasic acid anhydride (C) with the hydroxyl group of the epoxy acrylate, and provide a high level of alkali developability. Can be maintained. The reaction between the epoxy acrylate and the polybasic acid anhydride (C) can be performed in the same manner as the reaction between the polymer (I) and the polybasic acid anhydride (C). Moreover, polybasic acid anhydride (C) can be made to react with the mixture of polymer (I) and an epoxy acrylate, and a modified polymer (II) and a carboxyl group-containing epoxy acrylate can also be obtained simultaneously.

As the radical polymerizable monomer, either a monofunctional (one radical polymerizable double bond) monomer or a polyfunctional monomer (two or more radical polymerizable double bonds) can be used. The radical polymerizable monomer is involved in photopolymerization, and can improve the properties of the resulting cured product and can also adjust the viscosity of the photosensitive resin composition. The preferred amount of use in the case of using the radical polymerizable monomer is 5 to 500 parts by mass (more than 100 parts by mass of resin solids (total amount of the modified polymer solids of the present invention and the radical polymerizable resin solids). Preferably it is 10-100 mass parts).
Specific examples of the radical polymerizable monomer include an N-substituted maleimide component that is a raw material for obtaining the polymer (I), a hydroxyl group-containing monomer, and the copolymerizable monomer that may be used in combination. In addition to (monofunctional monomers), aromatic vinyl monomers such as divinylbenzene, diallyl phthalate, diallylbenzene phosphonate; (di) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane di (meth) ) (Meth) acrylic monomers such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris [2- (meth) acryloyloxyethyl] triazine; (Meta) 2- (vinyloxyethoxy) ethyl acrylate, 2- (isopropenoxyethoxyethoxy) ethyl (meth) acrylate, 2- (isopropenoxyethoxyethoxyethoxy) ethyl (meth) acrylate, 2 (meth) acrylic acid 2 -Vinyl (thio) ether compounds having radically polymerizable double bonds such as (isopropenoxyethoxyethoxyethoxyethoxy) ethyl; polyfunctional monomers having two or more radically polymerizable double bonds such as triallyl cyanurate Can be mentioned. These are suitably selected according to the use and required characteristics of the photosensitive resin composition, and can be used alone or in combination of two or more.

  From the viewpoint of workability and the like when applying the photosensitive resin composition of the present invention to a substrate, a solvent may be blended in the composition. As the solvent, a solvent that can be used when the polymer (I) is obtained by a solution polymerization method can be used here, and one or a mixture of two or more can be used. An appropriate amount may be used so as to achieve a viscosity.

  The photosensitive resin composition of the present invention can be thermally cured by using a known thermal polymerization initiator. However, for fine processing and image formation by photolithography, a photopolymerization initiator is added and photocuring is performed. It is preferable to make it.

  Known photopolymerization initiators can be used such as benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone. Acetophenones such as 4- (1-t-butyldioxy-1-methylethyl) acetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone; 2,4 -Thioxanthones such as dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; Ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; Benzophenone, 4- (1- -Benzophenones such as butyldioxy-1-methylethyl) benzophenone and 3,3 ', 4,4'-tetrakis (t-butyldioxycarbonyl) benzophenone; 2-methyl-1- [4- (methylthio) phenyl]- Examples include 2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; acylphosphine oxides and xanthones.

  These photopolymerization initiators are used as one kind or a mixture of two or more kinds, resin solids (total amount of the modified polymer solids of the present invention and radical polymerizable resin solids) and radicals that can be used as necessary. It is preferable that 0.5-30 mass parts is contained with respect to a total of 100 mass parts of polymerizable monomers. When the amount of the photopolymerization initiator is less than 0.5 parts by mass, it is necessary to increase the light irradiation time or it is difficult for polymerization to occur even if light irradiation is performed, so that an appropriate surface hardness can be obtained. Disappear. In addition, even if it mixes photopolymerization initiator exceeding 30 mass parts, there is no merit which uses it in large quantities.

  The photosensitive resin composition of the present invention may contain a compound having a functional group capable of reacting with two or more carboxyl groups in one molecule. Thus, a stronger cured coating film can be obtained by curing using light and heat in combination. When used for image formation, heat treatment after light irradiation and alkali development can increase the degree of crosslinking while consuming carboxyl groups in the cured coating film, and can improve physical properties such as durability.

  Examples of such a compound having a functional group capable of reacting with two or more carboxyl groups in one molecule include an epoxy compound, an oxazoline compound, and an oxetane compound. Specifically, examples of the epoxy compound include novolak type epoxy resin, bisphenol type epoxy resin, alicyclic epoxy resin, triglycidyl isosialate, and the like, and examples of the oxazoline compound include 1,3-phenylenebisoxazoline. The preferred amount used is 5 to 70 with respect to 100 parts by mass of the total of the resin solid content (total amount of the modified polymer solid content of the present invention and the radical polymerizable resin solid content) and the radical polymerizable monomer that can be used if necessary. A mass part and a more preferable usage-amount are 10-50 mass parts. At this time, a curing agent such as dicyandiamide or an imidazole compound may be used in combination.

  If necessary, the photosensitive resin composition of the present invention may further include a filler such as talc, clay, barium sulfate, a coloring pigment, an antifoaming agent, a coupling agent, a leveling agent, a sensitizer, and a release agent. Well-known additives such as lubricants, plasticizers, antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, thickeners, and the like may be added. Furthermore, various reinforcing fibers can be used as reinforcing fibers to form a fiber-reinforced composite material.

  When the photosensitive resin composition of the present invention is used for image formation, it is applied to a substrate, exposed to obtain a cured coating film, and then an unexposed portion is dissolved in an alkaline aqueous solution to perform alkali development. Specific examples of usable alkali 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 and dimethylamine , Trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dimethylpropylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, dimethylaminoethyl methacrylate, polyethyleneimine, etc. Emissions such may be mentioned, it is possible to use one or more of these.

  The photosensitive resin composition of the present invention can be used in the form of a dry film that is applied in advance to a film of polyethylene terephthalate or the like and dried in addition to the method of applying the photosensitive resin composition directly to a substrate in a liquid state. In this case, a dry film may be laminated on a substrate, and the film may be peeled off before or after exposure.

  In addition, the CTP (Computer To Plate) system, which is frequently used in the printing plate making field, that is, without using a pattern forming film during exposure, laser light is directly scanned and exposed on the coating film using digitized data. The drawing method can be adopted.

  The photosensitive resin composition of the present invention can have both sensitivity at the time of exposure and alkali developability, and further contains, as a resin component, a modified polymer that gives a cured product that is excellent in heat resistance but does not develop brittleness. Therefore, the physical properties of the cured product could be improved. Therefore, the photosensitive resin composition of the present invention is an alkali-developable photosensitive resin composition for image formation, such as a solder resist for printed wiring boards, an etching resist, an electroless plating resist, and a build-up method printed wiring board. It can be suitably used for various applications such as an insulating layer, liquid crystal display plate production, and printing plate making.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the present invention are within the technical scope of the present invention. Is included. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified. Moreover, the measuring method of each physical property value in the following examples is as follows.
[Weight average molecular weight]
The weight average molecular weight (Mw) was measured by GPC (gel permeation chromatography) under the following conditions. The sample solution was prepared by dissolving the polymer (I) in tetrahydrofuran (eluent) so that the solid content concentration was about 0.5%. Mw was determined from a calibration curve prepared using standard polystyrene (manufactured by Tosoh Corporation).
・ Column: One TSKgel SuperH2000, one TSKgel SuperHM-M, and one TSKgel Super2000 connected in series (all manufactured by Tosoh)
・ Eluent: Tetrahydrofuran ・ Eluent flow rate: 0.6 ml / min [conversion rate]
The conversion rate of each monomer component when obtaining the polymer (I) was determined under the following conditions using LC (liquid chromatography). The sample solution was prepared by diluting precisely weighed polymer solution (about 0.5 g) and weighed N, N-dimethylformamide (about 30 mg; used as an internal standard) to 100 ml with the following eluent. .
Column: TSK-gel ODS-80Ts (25 cm) (manufactured by Tosoh)
Eluent: 0.05% ammonium dihydrogen phosphate aqueous solution / acetonitrile = 50/50 (mass ratio)
・ Eluent flow rate: 0.5 ml / min ・ Detection wavelength: 210 nm
Calculated by
[Heat-resistant]
The heat resistance of the modified polymer (II) or (III) was evaluated by a thermogravimetric analysis (TGA) apparatus “Shimadzu DTG-50H”. The modified polymer solution (about 1 g) was added to pentane (about 30 g), the modified polymer was reprecipitated and recovered, dried under reduced pressure for 10 hours to remove volatile components, and then thermogravimetric analysis was performed. The temperature program is held at 100 ° C. for 10 minutes, then heated at 10 ° C./min, and reduced by 1.0% (temperature when the mass of the sample is reduced by 1.0%) and reduced by 5.0% The temperature (temperature when the mass of the sample was reduced by 5.0%) was determined. Since the decrease in mass is due to the thermal decomposition of the polymer, the higher the temperature, the higher the heat resistance.
[Developability]
Irgacure 907 (trade name; photopolymerization initiator manufactured by Ciba Specialty Chemicals) is added to the solid content of the mixture of the modified polymer (II) or (III) solution and the carboxyl group-containing epoxy acrylate (IIII) solution. On the other hand, 5% was added to make a uniform solution, and after coating on a copper plate so that the film thickness after drying was 50 μm, it was heated at 80 ° C. for 30 minutes. Thereafter, the film was immersed in a 1% aqueous sodium carbonate solution at 30 ° C., and the developability (alkali solubility) was evaluated by the time until the coating film was dissolved and removed.
[Photocurability]
The dried coating film obtained in the same manner as in the evaluation of developability was exposed to ² J / cm ² using an ultraviolet exposure device, and then immersed in a 1% aqueous sodium carbonate solution at 30 ° C. for 90 seconds. Photocurability was evaluated according to the degree of remaining.
[Flexibility]
For the solid content of the mixture of the modified polymer (II) or (III) solution and the carboxyl group-containing epoxy acrylate (IIII) solution, a phenol novolac type epoxy resin (trade name “YDPN-638P”; manufactured by Toto Kasei; 30% of epoxy equivalent 177), 5% of Irgacure 907 and 2% of dicyandiamide as a curing agent were added to form a uniform solution, and applied to a polyethylene terephthalate film so that the film thickness after drying was 100 μm. Heat at 30 ° C. for 30 minutes. Next, after performing exposure at ² J / cm ² using an ultraviolet exposure device, it was further heated at 160 ° C. for 1 hour. The specimen was cooled to room temperature, using a mandrel of 10 mm [phi, were evaluated bending resistance in accordance with 8.1 of JIS K 5400 ^-1990. The presence or absence of cracks was evaluated visually.
Examples 1 and 2 and Comparative Examples 1 and 2
Example 1
1) Synthesis of polymer (I-1) In a container equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen introduction tube and a dropping funnel, DBE-5 (trade name; manufactured by DuPont, dimethyl glutarate mainly) Component) 120 parts were charged, and the inside of the container was purged with nitrogen gas for 10 minutes, and then heated until the internal temperature reached 115 ° C. with stirring.

  Two dropping funnels were prepared, and one of them was charged with 20 parts of N-phenylmaleimide, 45.1 parts of 2-hydroxyethyl methacrylate and a solution (liquid A) obtained by mixing 35 parts of DBE-5 as a solvent. The inside of the dropping funnel was replaced with nitrogen gas for 5 minutes. In addition, a solution obtained by mixing 0.65 part of 1,1′-azobis (cyclohexane-1-carbonitrile) [V-40] as a polymerization initiator and 15 parts of DBE-5 as a solvent. (Liquid B) was charged, and the inside of the dropping funnel was replaced with nitrogen gas for 5 minutes.

  After nitrogen gas replacement of the container and the dropping funnel, the solution (A liquid and B liquid) in the two dropping funnels was dropped over 2 hours while maintaining the temperature in the container at 115 ° C. and continuing stirring. After completion of the dropwise addition, the mixture was further aged at 115 ° C. for 3 hours.

After the ripening, the conversion rate of each monomer was calculated. The conversion rate of N-phenylmaleimide was 99.3%, and the conversion rate of 2-hydroxyethyl methacrylate was 99.5%. From this result, the composition of the obtained polymer (I-1) is N-phenylmaleimide: 2-hydroxyethyl methacrylate = 25: 75 (molar ratio), and the polymer (solid content is 27.6%) ( I-1) A solution was obtained. Moreover, Mw of the obtained polymer (I-1) was 17000.
2) Synthesis of modified polymer (II-1) In a vessel equipped with a stirrer, thermometer and reflux condenser, 100 parts of the polymer (I-1) solution, 1,2,3,6-tetrahydroanhydrophthalic acid 14.5 parts of acid and 0.343 part of tetra-n-butylammonium chloride as a catalyst were charged and reacted at 115 ° C. for 6 hours with stirring. As a result, a modified polymer (II-1) solution having an acid value of 123 mgKOH / g and a solid content of 36.4% was obtained.
3) Synthesis of modified polymer (III-1), evaluation of heat resistance In a vessel equipped with a stirrer, thermometer, reflux condenser, 70 parts of the modified polymer (II-1) solution, 4.5 parts of glycidyl methacrylate Then, 0.018 part of 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl was charged as a polymerization inhibitor and reacted at 105 ° C. for 6 hours with stirring. As a result, a modified polymer (III-1) solution having an acid value of 51 mgKOH / g, a double bond equivalent of 1018 g / eq, and a solid content of 40.0% was obtained.

According to the TGA result of this modified polymer (III-1), the 1.0% reduction temperature was 245 ° C. and the 5.0% reduction temperature was 308 ° C.
4) Synthesis of carboxyl group-containing epoxy acrylate In a container equipped with a stirrer, thermometer, reflux condenser, and gas introduction tube, a cresol novolac type epoxy resin (trade name “YDCN-704A”; manufactured by Tohto Kasei; epoxy equivalent 205) 410 parts, 145 parts of acrylic acid, 299 parts of DBE-5, 1.7 parts of benzyltriphenylphosphonium chloride as an esterification catalyst and 0.5 parts of methylhydroquinone as a polymerization inhibitor were allowed to react at 120 ° C. for 15 hours. The acid value of the reaction product was confirmed to be 1.5 mgKOH / g. Next, 76 parts of DBE-5 and 142 parts of tetrahydrophthalic anhydride were added and reacted at 100 ° C. for 4 hours to prepare a DBE-5 solution containing 65% of carboxyl group-containing epoxy acrylate (IIII) having an acid value of 77 mgKOH / g. Obtained.
5) Preparation of photosensitive resin composition, developability, photocurability, bending resistance evaluation 10 parts of the modified polymer (III-1) solution and 6.2 parts of the carboxyl group-containing epoxy acrylate (IIII) solution Developability, photocurability, and bending resistance were evaluated by the above-described methods using a resin composition mixed with the above.
The developability was good, and the coating film was dissolved and removed by immersion for 60 seconds. The photocurability was also good, and the coated film after exposure was not changed even after being immersed in an aqueous sodium carbonate solution for 90 seconds. Even in the bending resistance evaluation, no cracks were observed.
Example 2
1) Synthesis of polymer (I-2) 40 parts of DBE-5 was charged as a solvent in a vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube and dropping funnel, and the inside of the vessel was filled with nitrogen gas for 10 minutes. After the replacement, the mixture was heated with stirring until the internal temperature reached 115 ° C.
Two dropping funnels were prepared, and one of them was obtained by mixing 20 parts of N-phenylmaleimide, 4 parts of styrene, 30 parts of 2-hydroxyethyl methacrylate and 40 parts of DBE-5 as a solvent (solution A). The inside of the dropping funnel was replaced with nitrogen gas for 5 minutes. In addition, a solution obtained by mixing 0.54 parts of 1,1′-azobis (cyclohexane-1-carbonitrile) [V-40] as a polymerization initiator and 20 parts of DBE-5 as a solvent. (Liquid B) was charged, and the inside of the dropping funnel was replaced with nitrogen gas for 5 minutes.

  After nitrogen gas replacement of the container and the dropping funnel, the solution (A liquid and B liquid) in the two dropping funnels was dropped over 2 hours while maintaining the temperature in the container at 115 ° C. and continuing stirring. After completion of the dropwise addition, the mixture was further aged at 115 ° C. for 3 hours.

After the ripening, the conversion rate of each monomer was calculated. The conversion rate of N-phenylmaleimide was 99.9%, the conversion rate of styrene was 100%, and the conversion rate of 2-hydroxyethyl methacrylate was 100%. It was. From this result, the composition of the obtained polymer (I-2) is N-phenylmaleimide: styrene: 2-hydroxyethyl methacrylate = 30: 10: 60 (molar ratio), and the solid content is 35.1%. A polymer (I-2) solution was obtained. Moreover, Mw of the obtained polymer (I-2) was 22000.
2) Synthesis of modified polymer (II-2) and evaluation of heat resistance In a vessel equipped with a stirrer, thermometer and reflux condenser, 100 parts of the polymer (I-2) solution, 1, 2, 3, 6 -14.7 parts of tetrahydrophthalic anhydride and 0.344 part of tetra-n-butylammonium chloride as a catalyst were added and reacted at 115 ° C for 6 hours with stirring. As a result, a modified polymer (II-2) solution having an acid value of 101 mgKOH / g and a solid content of 42.7% was obtained.
According to the TGA result of this modified polymer (II-2), the 1.0% reduction temperature was 220 ° C. and the 5.0% reduction temperature was 270 ° C.
3) Preparation of photosensitive resin composition, developability, photocurability, evaluation of bending resistance Carboxy group-containing epoxy acrylate (IIII) synthesized in Example 1 with 9.4 parts of the modified polymer (II-2) solution Using the resin composition obtained by mixing 6.2 parts of the above solution, the developability, photocurability and flex resistance were evaluated by the methods described above.
The developability was good, and the coating film was dissolved and removed by immersion for 60 seconds. The photocurability was also good, and the coated film after exposure was not changed even after being immersed in an aqueous sodium carbonate solution for 90 seconds. Even in the bending resistance evaluation, no cracks were observed.
Comparative Example 1
1) Synthesis of Comparative Polymer (I-3) 40 parts of DBE-5 was charged as a solvent in a container equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube and dropping funnel, and the inside of the container was maintained for 10 minutes. After replacing with nitrogen gas, the mixture was heated with stirring until the internal temperature reached 115 ° C.
Two dropping funnels are prepared, and one of them is charged with 16 parts of styrene, 30 parts of 2-hydroxyethyl methacrylate and 30 parts of DBE-5 as a solvent (solution A), and the inside of the dropping funnel is placed inside. The gas was replaced with nitrogen gas for 5 minutes. In addition, another one is obtained by mixing 0.46 part of 1,1′-azobis (cyclohexane-1-carbonitrile) [V-40] as a polymerization initiator and 20 parts of DBE-5 as a solvent. The solution (liquid B) was charged, and the inside of the dropping funnel was replaced with nitrogen gas for 5 minutes.
After nitrogen gas replacement of the container and the dropping funnel, the solution (A liquid and B liquid) in the two dropping funnels was dropped over 2 hours while maintaining the temperature in the container at 115 ° C. and continuing stirring. After completion of the dropwise addition, the mixture was further aged at 115 ° C. for 3 hours.
When the conversion rate of each monomer was calculated after completion of aging, the conversion rate of styrene was 100%, and the conversion rate of 2-hydroxyethyl methacrylate was 100%. From this result, the composition of the obtained comparative polymer (I-3) is styrene: 2-hydroxyethyl methacrylate = 40: 60 (molar ratio), and the comparative polymer having a solid content of 33.8% ( I-3) A solution was obtained. Further, Mw of the obtained comparative polymer (I-3) was 27000.
2) Synthesis of modified polymer for comparison (II-3) and evaluation of heat resistance In a container equipped with a stirrer, a thermometer and a reflux condenser, 100 parts of the above comparative polymer (I-3) solution, 1, 2 , 3,6-tetrahydrophthalic anhydride (15.3 parts) and tetra-n-butylammonium chloride (0.346 parts) as a catalyst were added and reacted at 115 ° C. for 6 hours with stirring. As a result, a comparative modified polymer (II-3) solution having an acid value of 107 mgKOH / g and a solid content of 41.9% was obtained.
According to the TGA result of this modified polymer (II-3), the 1.0% reduction temperature is 176 ° C. and the 5.0% reduction temperature is 202 ° C., confirming that the heat resistance is lower than that of the examples. did it.
3) Preparation of photosensitive resin composition, developability, photocurability, flex resistance evaluation Carboxyl group-containing epoxy acrylate synthesized in Example 1 with 9.5 parts of the comparative modified polymer (II-3) Using the resin composition obtained by mixing 6.2 parts of the solution (IIII), developability, photocurability, and flex resistance were evaluated by the above-described methods.
The developability was good, and the coating film was dissolved and removed by immersion for 60 seconds. The photocurability was also good, and the coated film after exposure was not changed even after being immersed in an aqueous sodium carbonate solution for 90 seconds. Even in the bending resistance evaluation, no cracks were observed.
Comparative Example 2
Using 12.3 parts of the carboxyl group-containing epoxy acrylate (IIII) solution synthesized in Example 1 (without using a modified polymer), developability, photocurability, and flex resistance were evaluated by the methods described above.

The developability was good, and the coating film was dissolved and removed by immersion for 60 seconds. The photocurability was also good, and the coated film after exposure was not changed even after being immersed in an aqueous sodium carbonate solution for 90 seconds. However, in the bending resistance evaluation, it was confirmed that cracks occurred and the bending resistance was inferior compared to the examples.

Claims (4)

A photosensitive resin composition capable of forming a coating film capable of alkali development,
A polybasic acid for at least part of the hydroxyl groups of the polymer (I) obtained by radical polymerization of the N-substituted maleimide component (A) and the hydroxyl group-containing monomer (B) as essential components A radical polymerizable monomer having a functional group capable of reacting with a carboxyl group with respect to at least a part of the carboxyl group of the modified polymer (II) having a carboxyl group obtained by reacting the anhydride (C) ( A photosensitive resin composition comprising a modified polymer (III) having a radical polymerizable double bond obtained by reacting D). The photosensitive resin composition of Claim 1 in which epoxy (meth) acrylate is contained. Furthermore, the photosensitive resin composition of Claim 1 or 2 in which the compound which has a functional group which can react with two or more carboxyl groups is contained in 1 molecule. A polybasic acid for at least part of the hydroxyl groups of the polymer (I) obtained by radical polymerization of the N-substituted maleimide component (A) and the hydroxyl group-containing monomer (B) as essential components A modified polymer (II) having a carboxyl group characterized by reacting an anhydride (C) is obtained, and at least a part of the hydroxyl group and / or carboxyl group of the carboxyl group-containing modified polymer (II) is obtained. On the other hand, a method for producing a modified polymer (III) having a radical polymerizable double bond, which comprises reacting a radical polymerizable monomer (D) having a functional group capable of reacting with these groups.