JP2006206728A - Modified epoxy resin, method for producing the same, photosensitive resin composition, and photosensitive element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a modified epoxy resin capable of preparing a photosensitive resin composition which is excellent in film-forming properties and can sufficiently satisfy properties required for a permanent mask formed on a substrate in the form of film such as an FPC cover lay, and to provide a method for producing the same and a photosensitive resin composition thereof. <P>SOLUTION: The modified epoxy resin has a structural unit represented by general formula (1), wherein R<SP>1</SP>denotes a bivalent organic group which is a residue of a diglycidyl ether-type epoxy compound; R<SP>2</SP>denotes a group represented by general formula (2) (wherein R<SP>4</SP>denotes a bivalent organic group which is a diisocyanate compound residue; R<SP>5</SP>denotes a bivalent organic group which is a diacid residue; and m denotes an integer of 1 or more); and R<SP>3</SP>denotes a hydrogen atom or a group represented by general formula (3) (wherein R<SP>6</SP>denotes an acid anhydride residue). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a modified epoxy resin, a production method thereof, a photosensitive resin composition, and a photosensitive element.

  Conventionally, a film-like printed wiring board called a flexible printed circuit (hereinafter referred to as “FPC”) has been used for small devices such as cameras, magnetic heads, and mobile phones. This is because the FPC can maintain its function even when it is bent, and is optimal as a printed wiring board to be accommodated in a small device as described above. Particularly in recent years, there has been an increasing demand for further miniaturization and weight reduction of various electronic devices. By adopting FPC for wiring such devices, the size and weight of the small devices are reduced, and the product cost is reduced. Reduction, simplification of design, and the like have been realized.

  The solder resist used in this FPC is required to have developability, high resolution, insulation, solder heat resistance, etc., similar to the solder resist used in ordinary printed wiring boards. In addition, the FPC is bent. Flexibility is also required so as not to be broken.

  At present, as a solder resist provided in the FPC, a cover lay formed by punching a polyimide film with an adhesive is most often used because the above various characteristics are relatively satisfied. However, this cover lay has a high manufacturing cost because the mold used for die cutting is very expensive and the cover lay is manually aligned and bonded together. There is a problem that. Furthermore, even if the FPC is adopted to meet the demand for downsizing of electronic devices, if an FPC is provided with a solder resist using a coverlay, it becomes difficult to form a fine pattern. There is also a problem.

  In order to solve these problems, a liquid containing an unsaturated group-containing polycarboxylic acid resin obtained by reacting an addition product of a specific epoxy resin and an unsaturated monocarboxylic acid with succinic anhydride or the like. Ink compositions for FPC have been proposed (see, for example, Patent Document 1 and Patent Document 2).

  In addition, a product obtained by reacting a mixture of a novolac epoxy resin and a rubber-modified bisphenol A type epoxy resin with an ethylenically unsaturated carboxylic acid with the intention of forming a flexible solder resist, A liquid photosensitive resin composition containing a reaction product with a basic acid or the like has been proposed (see, for example, Patent Document 3).

JP-A-7-207211 JP-A-8-134390 Japanese Patent Laid-Open No. 9-5997

  However, even conventional liquid FPC ink compositions and photosensitive resin compositions including those described in Patent Documents 1 to 3 can sufficiently satisfy the flexibility required for FPC. It was not a thing.

  Furthermore, conventional liquid FPC ink compositions and photosensitive resin compositions, including those described in Patent Documents 1 to 3, have insufficient coating properties, and the coating films of these compositions. When the film is formed on an FPC or the like, the coating film becomes sticky, so that there is a problem that workability is lowered.

  Here, it is conceivable to increase the molecular weight of the modified epoxy resin in order to improve the coating property. Usually, the photosensitive resin composition is applied on a printed wiring board and partially cured, and then developed with a dilute alkaline aqueous solution to peel off and remove the uncured portion. In the case of the composition, even after development with a dilute alkaline aqueous solution after curing, if the weight average molecular weight of the modified epoxy resin is large, the uncured portion is not sufficiently peeled and removed, and sufficient resolution may not be obtained. .

  Therefore, the present invention has been made in view of the above circumstances, and has sufficiently excellent coating properties and has characteristics required as a permanent mask formed on a film-like substrate such as an FPC coverlay. It aims at providing the modified epoxy resin which can prepare the photosensitive resin composition which can fully be satisfied, its manufacturing method, and its photosensitive resin composition. It is another object of the present invention to provide a photosensitive element provided with such a photosensitive resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by incorporating a modified epoxy resin having a specific structure into the photosensitive resin composition, and the present invention has been completed. It came to do.

で表される構造単位を有することを特徴とする。ここで、式（１）中、Ｒ^１はジグリシジルエーテル型エポキシ化合物残基である二価の有機基を示し、Ｒ^２は下記一般式（２）；

（式中、Ｒ^４はジイソシアネート化合物残基である二価の有機基を示し、Ｒ^５は二塩基酸残基である二価の有機基を示し、ｍは１以上の整数を示す。）で表される基を示し、Ｒ^３は水素原子或いは下記一般式（３）；

（式中、Ｒ^６は酸無水物残基を示す。）
で表される基を示し、ｎは１以上の整数を示す。 That is, the modified epoxy resin of the present invention has the following general formula (1);

It has the structural unit represented by these. Here, in the formula (1), R ¹ represents a divalent organic group which is a diglycidyl ether type epoxy compound residue, and R ² represents the following general formula (2);

(Wherein R ⁴ represents a divalent organic group that is a diisocyanate compound residue, R ⁵ represents a divalent organic group that is a dibasic acid residue, and m represents an integer of 1 or more). R ³ represents a hydrogen atom or the following general formula (3);

(In the formula, R ⁶ represents an acid anhydride residue.)
And n represents an integer of 1 or more.

  In this specification, “modified epoxy resin” refers to a resin obtained by modifying an epoxy compound (epoxy resin). Does the “modified epoxy resin” itself have an epoxy group (glycidyl group)? Whether or not.

で表される化合物のことをいう。ここで、Ｒ^７は二価の有機基を示す。 Further, the “diglycidyl ether type epoxy compound” means the following general formula (4):

The compound represented by these. Here, R ⁷ represents a divalent organic group.

  The modified epoxy resin of the present invention comprises a preparation step of preparing a first intermediate product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid, a diglycidyl ether type epoxy compound, and a first intermediate product. It is obtained by a method for producing a modified epoxy resin comprising a first step of obtaining a second intermediate product by the polymerization reaction of and a second step of adding an acid anhydride to the second intermediate product.

  Such a modified epoxy resin has an ester-type chain bond, and since the whole molecule tends to have a chain structure, it is considered that gelation tends to be difficult. Therefore, the photosensitive element provided with the photosensitive resin composition layer formed of the photosensitive resin composition containing such a modified epoxy resin was prepared using a dilute alkaline aqueous solution when a resist film was formed using the photosensitive element. Development can be performed satisfactorily. Moreover, since the above-mentioned modified epoxy resin contains an amide group, the cured film obtained by thermally curing the photosensitive resin composition layer containing the modified epoxy resin has sufficient flexibility as a permanent mask for FPC. Can have. Further, even when a cured film is formed only on one side of the FPC, an effect that the FPC is hardly warped can be obtained. Furthermore, the effect which improves the flame retardance of FPC is also acquired.

  Since the first intermediate product is synthesized by a polymerization reaction of a diisocyanate compound and a dibasic acid, the molecular weight tends to increase and the acid value of the modified epoxy resin may decrease. Therefore, in the polymerization reaction of the first step, a dibasic acid may be further added for the purpose of adjusting the acid value of the modified epoxy resin. Thereby, the developability by dilute alkaline aqueous solution can be prepared.

  Further, among the modified epoxy resins obtained as described above, those obtained by using dicarboxylic acid as a dibasic acid, and a chain due to an ester bond formed by a reaction between a carboxyl group and a glycidyl group in the molecule. A modified epoxy resin having a shape structure is preferable because it tends to realize excellent alkali developability.

  The modified epoxy resin having such a structure preferably has a weight average molecular weight of 10,000 to 70,000. Thereby, the photosensitive resin composition containing such a modified epoxy resin can satisfy all of the coating properties and the developability with a dilute alkaline aqueous solution at a higher level. Furthermore, the effect that storage stability can be ensured more reliably is also acquired.

  Moreover, it is preferable that the modified epoxy resin has an acid value of 70 to 150 mgKOH / g. Thereby, it exists in the tendency which the electrical insulation of a cured film of the photosensitive resin composition containing this modified epoxy resin, chemical resistance, plating resistance, etc. improve further.

  Furthermore, the method for producing the modified epoxy resin of the present invention comprises a preparation step of preparing a first intermediate product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid, a diglycidyl ether type epoxy compound and a first intermediate A first step of obtaining a second intermediate product by a polymerization reaction with the product, and a second step of adding an acid anhydride to the second intermediate product are provided. The modified epoxy resin produced in this way can form a chain structure by an ester bond, a network structure by an ether bond, and a network structure by an ester bond in the molecule, so that alkali developability can be adjusted. . Moreover, since the modified epoxy resin obtained by said manufacturing method contains an amide group, the cured film obtained by thermosetting the photosensitive resin composition layer containing this modified epoxy resin is used as a permanent mask of FPC. It can have sufficient flexibility. Further, even when a cured film is formed only on one side of the FPC, an effect that the FPC is hardly warped can be obtained. Furthermore, the effect which improves the flame retardance of FPC is also acquired.

  In this case, it is preferable to use a dicarboxylic acid as the dibasic acid because the above effect tends to be further exhibited.

  In this method for producing an epoxy resin, it is preferable to use a tertiary amine having a pKa of 9.0 or less as a polymerization reaction catalyst. Thereby, the developability of the resist film formed using the resin with a dilute alkaline aqueous solution tends to be improved. “Ka” represents an acid dissociation constant, and “pKa” represents a numerical value defined by pKa = −log (Ka).

  The present invention also includes (A) the above-described modified epoxy resin, (B) a photopolymerizable compound having at least one ethylenically unsaturated group in the molecule, and (C) a photopolymerization initiator. A photosensitive resin composition is provided.

  This photosensitive resin composition is formed on a film-like substrate such as an FPC cover lay while having excellent coating properties by using the above components (A) to (C) as essential components. The properties required for permanent masks (especially photosensitivity, resolution, soldering heat resistance, and flexibility) can be fully satisfied. As a result, the characteristics of photosensitive elements are improved and high resolution and high density are achieved. Efficient production of printed wiring boards is possible.

  Moreover, the photosensitive resin composition of this invention mentioned above can be used in order to form a flexible cured resin on a film-form base material. Therefore, for example, by curing the photosensitive resin composition and using it as an FPC permanent mask, even if the FPC is bent, the permanent mask can be prevented from being destroyed.

  Furthermore, the present invention provides a photosensitive element comprising a support and a photosensitive resin composition layer made of the above-described photosensitive resin composition formed on the support. .

  When such a photosensitive element is used, it is excellent in developability, high resolution, solder heat resistance, and flexibility, and this enables efficient production of printed wiring boards with high resolution and high adhesion. It becomes possible.

  According to the present invention, a photosensitive resin composition that is sufficiently excellent in coating properties and that can sufficiently satisfy the characteristics required as a permanent mask formed on a film-like substrate such as an FPC coverlay. The modified epoxy resin which can prepare a thing, its manufacturing method, and its photosensitive resin composition can be provided. Moreover, this invention can also provide the photosensitive element provided with such a photosensitive resin composition.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding thereto, (meth) acrylate means acrylate and corresponding methacrylate, (meth) acryloyl group means acryloyl group and The methacryloyl group corresponding to it means a (meth) acryloxy group means an acryloxy group and a methacryloxy group corresponding to it.

で表される構造単位を有することを特徴とする。ここで、式（１）中、Ｒ^１はジグリシジルエーテル型エポキシ化合物残基である二価の有機基を示し、Ｒ^２は下記一般式（２）；

（式中、Ｒ^４はジイソシアネート化合物残基である二価の有機基を示し、Ｒ^５は二塩基酸残基である二価の有機基を示し、ｍは１以上の整数を示す。）で表される基を示し、Ｒ^３は水素原子或いは下記一般式（３）；

（式中、Ｒ^６は酸無水物残基を示す。）
で表される基を示し、ｎは１以上の整数を示す。 The modified epoxy resin of the present invention has the following general formula (1);

It has the structural unit represented by these. Here, in the formula (1), R ¹ represents a divalent organic group which is a diglycidyl ether type epoxy compound residue, and R ² represents the following general formula (2);

(Wherein R ⁴ represents a divalent organic group that is a diisocyanate compound residue, R ⁵ represents a divalent organic group that is a dibasic acid residue, and m represents an integer of 1 or more). R ³ represents a hydrogen atom or the following general formula (3);

(In the formula, R ⁶ represents an acid anhydride residue.)
And n represents an integer of 1 or more.

  The weight average molecular weight (Mw) of the modified epoxy resin can be measured by gel permeation chromatography (GPC) (in terms of standard polystyrene). According to this measurement method, Mw of the modified epoxy resin is preferably 10,000 to 70,000 from the viewpoint of coating properties (difficulty in stickiness) and developability with a dilute aqueous alkali solution, and is 20,000 to 50,000. More preferably it is.

In the structural formula of the modified epoxy resin represented by the general formula (1) described above, the upper limit value of n depends on the types of residues of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ . Although it changes suitably, it is preferable to set the value of n as this upper limit so that this weight average molecular weight may be 70000.

The acid value of the modified epoxy resin can be measured by the following method. First, about 1 g of the modified epoxy resin solution of the present invention is precisely weighed, 30 g of acetone is added to the resin solution, and the resin solution is uniformly dissolved. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous KOH solution. And from the titration result, the following general formula (5);
A = 10 × Vf × 56.1 / (Wp × I) (5)
To calculate the acid value. In the formula, A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of phenolphthalein, Wp represents the weight (g) of the modified epoxy resin solution, and I represents the weight of the modified epoxy resin solution. The ratio of non-volatile content (% by mass) is shown.

  According to this measurement method, the acid value of the modified epoxy resin is 70 to 150 mgKOH from the viewpoint of developability with a dilute alkaline aqueous solution and the electrical insulation, chemical resistance and plating resistance of the resulting cured film. / G, more preferably 90 to 135 mgKOH / g.

  Next, the manufacturing method of the modified epoxy resin mentioned above is demonstrated.

  The method for producing a modified epoxy resin described above includes a preparation step of preparing a first intermediate product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid, a diglycidyl ether type epoxy compound, and a first intermediate product. A first step of obtaining a second intermediate product by the polymerization reaction of and a second step of adding an acid anhydride to the second intermediate product.

(Preparation process)
Examples of the diisocyanate compound used as a raw material in the preparation step include toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diene. Aromatic diisocyanate compounds such as isocyanate, tetramethylxylylene diisocyanate, 1,4-phenylene diisocyanate; isophorone diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate Alicyclic diisocyanate compounds such as 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, , 6-hexamethylene diisocyanate, 2,2,4-trimethyl - hexamethylene-1,6-diisocyanate, and aliphatic diisocyanate compounds such as lysine diisocyanate and the like. These can be used individually by 1 type or in combination of 2 or more types. Among these diisocyanate compounds, 2,2,4-trimethyl-hexamethylene-1,6-diisocyanate is more preferable from the viewpoint of flexibility of the resulting modified epoxy resin.

  As the dibasic acid used as a raw material in the preparation step, dicarboxylic acid is preferable. Specifically, for example, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid , Methylhexahydrophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, 2,6-naphthalenedicarboxylic acid, 2, Examples include 7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like. These can be used individually by 1 type or in combination of 2 or more types. Among these dibasic acids, sebacic acid is more preferable from the viewpoint that side reactions hardly occur.

  The polymerization reaction between the diisocyanate compound and the dibasic acid can be performed by a conventional method. The compounding ratio of the diisocyanate compound and the dibasic acid is determined based on the functional group equivalent ratio (carboxyl) from the viewpoint of the molecular weight of the modified epoxy resin, the viewpoint of developability with a dilute aqueous alkali solution, the viewpoint of storage stability, and the viewpoint of coating properties. (Group / isocyanate group), it is preferably 1.18 to 1.95.

  In the polymerization reaction between the diisocyanate compound and the dibasic acid, the polymerization reaction proceeds without using a catalyst, but it is preferable to use from the viewpoint of the polymerization reaction rate and the prevention of the side reaction. Examples of the catalyst used include phosphines, alkali metal compounds, and amines. Specifically, for example, phosphines such as tributylphosphine and triphenylphosphine, alkali metal compounds such as sodium hydroxide, lithium hydroxide, and potassium hydroxide, triethanolamine, N, N′-dimethylpiperazine, triethylamine, triethylamine, Examples include amines such as -n-propylamine, hexamethylenetetramine, pyridine, tetramethylammonium bromide, dimethylaniline, diethylaniline, dimethylparatoluidine, and diethylparatoluidine. These can be used individually by 1 type or in combination of 2 or more types.

  The amount of the catalyst used is from the viewpoint of the polymerization reaction rate, and from the viewpoint of the heat resistance and galvanic insulation of the cured film obtained from the photosensitive resin composition, with respect to 100 parts by mass of the total amount of diisocyanate compound and dibasic acid 1 to 10 parts by mass is preferable.

  The reaction temperature in the polymerization reaction between the diisocyanate compound and the dibasic acid is preferably 100 to 150 ° C. from the viewpoint of the polymerization reaction rate and the prevention of the side reaction.

  In this embodiment, it is preferable that the weight average molecular weights of the 1st intermediate product obtained above are 450-3000, and it is more preferable that it is 500-2000. When the weight average molecular weight of the first intermediate product is 450 to 3000, it is possible to sufficiently increase the amide group content of the finally obtained modified epoxy resin, and the cured film has sufficient flexibility. Can have.

  Moreover, in this embodiment, it is preferable that the acid value of the 1st intermediate product obtained above is 50-200 mgKOH / g, and it is more preferable that it is 70-170 mgKOH / g. When the acid value of the first intermediate product is 50 to 200 mg KOH / g, the acid value of the modified epoxy resin finally obtained can be made sufficiently high, and development with a dilute alkaline aqueous solution is more reliably performed. it can.

(First step)
Although the diglycidyl ether type epoxy compound used as a raw material in the first step is not particularly limited, it preferably has one or more phenoxy groups in one molecule, and further has two or more phenoxy groups in one molecule. It is more preferable.

  Examples of such epoxy compounds include bisphenol A type epoxy resins such as bisphenol A diglycidyl ether, bisphenol F type epoxy resins such as bisphenol F diglycidyl ether, bisphenol S type epoxy resins such as bisphenol S diglycidyl ether, and biphenol. Biphenol type epoxy resins such as diglycidyl ether, bixylenol type epoxy resins such as bixylenol diglycidyl ether, hydrogenated bisphenol A type epoxy resins such as hydrogenated bisphenol A diglycidyl ether, and their dibasic acid-modified diglycidyl Examples include ether type epoxy resins. Among these, bisphenol A type epoxy resins are preferred because they are excellent in heat resistance and chemical resistance and do not relatively shrink due to curing. These can be used individually by 1 type or in combination of 2 or more types.

  Commercially available compounds can be used as these compounds. For example, as bisphenol A diglycidyl ether, Epicoat 828, Epicoat 1001 and Epicoat 1002 (all manufactured by Japan Epoxy Resin Co., Ltd., trade name) can be exemplified. Examples of bisphenol F diglycidyl ether include Epicoat 807 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.), and examples of bisphenol S diglycidyl ether include EBPS-200 (trade name, manufactured by Nippon Kayaku Co., Ltd.) and Epicron. EXA-1514 (manufactured by Dainippon Ink & Chemicals, Inc., trade name) and the like can be mentioned. Examples of the biphenol diglycidyl ether include YL-6121 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.), and examples of the bixylenol diglycidyl ether include YX-4000 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.). Can be mentioned. Furthermore, examples of the hydrogenated bisphenol A diglycidyl ether include ST-2004 and ST-2007 (both manufactured by Tohto Kasei Co., Ltd., trade names) and the like. As the above-mentioned dibasic acid-modified diglycidyl ether type epoxy resin, Can include ST-5100 and ST-5080 (both manufactured by Tohto Kasei Co., Ltd., trade names).

  The epoxy equivalent of these diglycidyl ether type epoxy compounds (gram weight of the compound containing 1 equivalent of an epoxy group) can be measured according to JIS K 7236 “How to determine the epoxy equivalent of an epoxy resin”. According to this measurement method, the epoxy equivalent of the epoxy compound is preferably 160 to 3300, and more preferably 180 to 980, from the viewpoint of developability with a dilute aqueous alkali solution.

  The first intermediate product used in the first step is a product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid, and the product contains an amide group-containing dibasic acid. In the present embodiment, in addition to the first intermediate product containing an amide group-containing dibasic acid, a dibasic acid other than another amide group-containing dibasic acid may be used in combination.

  As the dibasic acid other than the amide group-containing dibasic acid described above, dicarboxylic acid is preferable. Specifically, for example, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexa Hydrophthalic acid, methylhexahydrophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, 2,6-naphthalenedicarboxylic acid 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like. These can be used individually by 1 type or in combination of 2 or more types. Of these dibasic acids, tetrahydrophthalic acid is more preferred.

  The polymerization reaction in the first step can be performed by a conventional method. When the diglycidyl ether type epoxy compound and the first intermediate product are used in combination, or when a dibasic acid other than an amide group-containing dibasic acid is used in combination, the diglycidyl ether type epoxy compound and the first intermediate The blending ratio of the product and the total of dibasic acids other than the amide group-containing dibasic acid is based on the molecular weight of the modified epoxy resin, the developability from a dilute alkali aqueous solution, the storage stability, and the coating properties. From the viewpoint, it is preferably 1.03 to 1.30 in terms of functional group equivalent ratio (carboxyl group / epoxy group).

  Examples of the catalyst used for the polymerization reaction in the first step include phosphines, alkali metal compounds, and amines. Specifically, for example, phosphines such as tributylphosphine and triphenylphosphine, alkali metal compounds such as sodium hydroxide, lithium hydroxide, and potassium hydroxide, triethanolamine, N, N′-dimethylpiperazine, triethylamine, triethylamine, Examples include amines such as -n-propylamine, hexamethylenetetramine, pyridine, tetramethylammonium bromide, dimethylaniline, diethylaniline, dimethylparatoluidine, and diethylparatoluidine. These can be used individually by 1 type or in combination of 2 or more types.

  Among these, as the catalyst used for the polymerization reaction in the first step, a tertiary amine having a pKa of 9.0 or less is preferable, and a tertiary amine having a pKa of 7.3 or less is more preferable. By using such a catalyst, it is possible to selectively synthesize a modified epoxy resin having a structural unit represented by the general formula (1) described above. Of the specific catalysts described above, from the viewpoint of preventing gelation due to the bond type (ether type network bond and / or ester type network bond) in the resulting modified epoxy resin, other than phosphines and alkali metal compounds. Or a tertiary amine having a pKa of 9.0 or less is preferable.

  The second intermediate product produced by the polymerization reaction in the first step described above is a chain structure by an ester bond produced by the reaction between a carboxyl group and a glycidyl group, and a reaction between the hydroxyl group and the glycidyl group. A network structure based on the generated ether bond and a network structure based on an ester bond generated by a reaction between a hydroxyl group and a carboxyl group can be formed. When the obtained second intermediate product has a large number of network structures based on ether bonds and network structures based on ester bonds among these structures, it is considered that the resulting second intermediate product tends to form a three-dimensional structure as a whole. Accordingly, since such an intermediate product and a modified epoxy resin obtained after the second step described later tend to gel, the uncured portion of the resist film formed by using such a resin is diluted with a dilute alkaline aqueous solution or the like. It tends not to be removed even by the development used.

  On the other hand, the second intermediate product synthesized by using the above-described catalyst is subjected to a second step using the second intermediate product to start with those having the structural unit represented by the general formula (1). Since it is possible to obtain a modified epoxy resin having many chain bonds due to ester bonds in the molecule and having a chain structure as a whole, it is considered that gelation tends to be difficult. Accordingly, the uncured portion of the resist film formed by using such a modified epoxy resin is easily removed by development using a dilute alkaline aqueous solution or the like.

  The amount of the catalyst used is such that the diglycidyl ether type epoxy compound and the first intermediate product are used from the viewpoints of the polymerization reaction rate and the heat resistance and galvanic insulation of the cured film obtained from the photosensitive resin composition. 100 parts by mass of the total amount of dibasic acid other than amide group-containing dibasic acid, or dibasic acid other than amide group-containing dibasic acid, diglycidyl ether type epoxy compound, first intermediate product It is preferable that it is 1-10 mass parts with respect to 100 mass parts of total amount.

  The reaction temperature in the first step is preferably 100 to 150 ° C. from the viewpoint of the polymerization reaction rate and the prevention of the side reaction.

(Second step)
In the second step, a modified epoxy resin is produced by reacting the second intermediate product produced in the first step with an acid anhydride.

  Examples of the acid anhydride used in the second step include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, Dibasic acid anhydrides such as methylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, etc. Aromatic polyvalent carboxylic acid anhydrides and other polyvalent carboxylic acids such as 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride And acid anhydride derivatives.

  Of these, dibasic acid anhydrides are preferably used, and dicarboxylic acid anhydrides are more preferably used. These can be used individually by 1 type or in combination of 2 or more types.

  The amount of acid anhydride added is determined from the viewpoint of developability with a dilute alkaline aqueous solution, the heat resistance of the cured film finally obtained, and the viewpoint of galvanic insulation, etc. The acid anhydride group / hydroxyl group of the second intermediate product produced in the first step) is preferably 0.6 to 1.3.

  The reaction temperature in the second step is preferably 80 to 130 ° C. from the viewpoint of reaction rate and the prevention of side reactions.

  Moreover, in this modified epoxy resin production method, an appropriate amount of solvent is usually used. Specifically, for example, ketone compounds such as methyl isobutyl ketone, cyclohexanone or methylcyclohexanone, aromatic hydrocarbon compounds such as toluene, xylene or tetramethylbenzene, cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methylcarbitol, butyl Carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, glycol ether compounds such as dipropylene glycol diethyl ether or triethylene glycol monoethyl ether, ester compounds such as acetate compounds of the above glycol ether compounds, ethylene glycol or propylene glycol Alcohol compounds such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha Ku can be mentioned petroleum-based solvents such as solvent naphtha.

  The modified epoxy resin of the present invention thus obtained is used, for example, in a photosensitive resin composition. The photosensitive resin composition includes (B) a photopolymerizable compound having at least one ethylenically unsaturated group in the molecule, in addition to the above-described modified epoxy resin (referred to as component (A)), and (C) A photopolymerization initiator.

  As the photopolymerizable compound (hereinafter simply referred to as “photopolymerizable compound”) having at least one ethylenically unsaturated group in the molecule as the component (B), for example, a bisphenol A (meth) acrylate compound; Compound obtained by reacting polyhydric alcohol with α, β-unsaturated carboxylic acid; Compound obtained by reacting glycidyl group-containing compound with α, β-unsaturated carboxylic acid; (meth) acrylate compound having urethane bond In addition to these, nonylphenoxy polyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl -Β '-(meth) acryloyloxyalkyl-o-phthalate and other lids Acid compounds; (meth) acrylic acid alkyl esters, EO-modified nonylphenyl (meth) acrylate or the like can be exemplified. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexa) Decaethoxy) phenyl) propane and the like, and 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is BPE-5. 0 (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name) and 2,2-bis (4- (methacryloxypentadecaethoxy) phenyl) propane is BPE-1300 (manufactured by Shin-Nakamura Chemical Co., Ltd., (Commercial name) is commercially available. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic) Xinonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxydodecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl) propane, 2,2-bis ( 4-((meth) acryloxytetradecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl) propane and 2,2-bis (4-((meth)) And acryloxyhexadecapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups. Polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) A Examples thereof include acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These can be used individually by 1 type or in combination of 2 or more types.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. Further, “EO modified” means having a block structure of ethylene oxide units (—CH ₂ —CH ₂ —O—), and “PO modified” means propylene oxide units (—CH ₂ —CH (CH ₃ )). -O-) having a block structure.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate and 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl and the like. Examples of the α, β-unsaturated carboxylic acid include (meth) acrylic acid.

  Examples of urethane monomers include (meth) acrylic monomers having an OH group at the β-position and diisocyanate compounds such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Examples include addition reaction products, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, and EO or PO-modified urethane di (meth) acrylate.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. It is done.

  These (B) components can be used individually by 1 type or in combination of 2 or more types.

  Examples of the photopolymerization initiator that is the component (C) include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl). Aromatic ketones such as butanone-1,2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1; quinones such as alkylanthraquinones; benzoin ether compounds such as benzoin alkyl ethers; Benzoin compounds such as alkylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2,4,5-triarylimidazole dimer; 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane, etc. Acridine derivatives; N-phenylglycine, N-phenylglycine derivative ; Coumarin compounds and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the component (A) in the photosensitive resin composition is from the viewpoint of preventing exudation from the end face of the photosensitive film provided with the photosensitive resin composition layer, and from the viewpoint of solder heat resistance and photosensitivity. (A) It is preferable that it is 30-70 mass parts with respect to 100 mass parts of total amounts of a component and (B) component, and it is more preferable that it is 45-55 mass parts.

  The content of the component (B) is preferably 10 to 70 parts by mass and more preferably 35 to 55 parts by mass with respect to 100 parts by mass as the total of the components (A) and (B). . If this content is less than 10 parts by mass, the photosensitivity tends to be insufficient, and if it exceeds 70 parts by mass, the photocured product tends to be brittle.

  (C) Content of a component shall be 0.1-20 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component from a viewpoint of photosensitivity and a viewpoint of solder heat resistance. Is preferable, and it is more preferable that it is 0.2-10 mass parts.

  In addition, the photosensitive resin composition includes a thermosetting component such as a melamine resin or an isocyanate block, a dye such as malachite green, a photochromic agent such as tribromophenylsulfone or leucocrystal violet, and a thermochromic material as necessary. Inhibitors, plasticizers such as p-toluenesulfonamide, phthalocyanine-based organic pigments such as phthalocyanine green or phthalocyanine blue, azo-based organic pigments or inorganic pigments such as titanium dioxide, silica, alumina, talc, calcium carbonate or barium sulfate Filler, defoaming agent, flame retardant, stabilizer, adhesion-imparting agent, leveling agent, antioxidant, fragrance or imaging agent made of inorganic pigments, 100 mass in total of component (A) and component (B) Each part can be contained in an amount of about 0.01 to 20 parts by mass.These can be used individually by 1 type or in combination of 2 or more types. Moreover, you may use together polymer components other than (A) component, such as an acrylic copolymer and an acid-modified vinyl group containing epoxy resin.

  Furthermore, the photosensitive resin composition may be mixed with a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof as necessary. It melt | dissolves and it can apply | coat as a solution about 30-70 mass% of solid content.

  Next, the photosensitive element of the present invention will be described.

  The photosensitive element of this invention is equipped with the support body and the photosensitive resin composition layer which consists of the photosensitive resin composition of this invention formed on the support body. A protective film for covering the photosensitive resin composition layer may be further provided on the photosensitive resin composition layer.

  The photosensitive resin composition layer is obtained by dissolving the photosensitive resin composition of the present invention in the above solvent or mixed solvent to obtain a solution having a solid content of about 30 to 70% by mass, and then applying the solution onto a support. Preferably formed. Although the thickness of the photosensitive resin composition layer varies depending on the use, it is preferably 10 to 100 μm and more preferably 20 to 60 μm in thickness after drying after removing the solvent by heating and / or hot air blowing. . If the thickness is less than 10 μm, it tends to be difficult to apply industrially, and if it exceeds 100 μm, the above-described effects produced by the present invention tend to be reduced, and in particular, flexibility and resolution tend to decrease.

  Examples of the support provided in the photosensitive element include a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  The thickness of the support is preferably 5 to 100 μm, and more preferably 10 to 30 μm. If the thickness is less than 5 μm, the support tends to be broken when the support is peeled off before development, and if it exceeds 100 μm, the resolution and flexibility tend to decrease.

  The photosensitive element consisting of two layers of the support and the photosensitive resin composition layer as described above or the photosensitive element consisting of three layers of the support, the photosensitive resin composition layer and the protective film is stored, for example, as it is. Alternatively, the protective film may be interposed and wound around the core in a roll shape and stored.

  The method for forming a resist pattern using the photosensitive element of the present invention includes a removal step of removing the protective film from the photosensitive element as necessary, the photosensitive element in the order of the photosensitive resin composition layer, and the support. A laminating step for laminating on a circuit forming substrate, and an actinic ray is irradiated to a predetermined portion of the photosensitive resin composition layer through a support as necessary, and a photocured portion is formed on the photosensitive resin composition layer. It includes an exposure step to be formed and a development step for removing the photosensitive resin composition layer other than the photocured portion. The circuit-forming substrate is an insulating layer and a conductor layer (copper, copper-based alloy, iron-based alloy such as nickel, chromium, iron, stainless steel, preferably copper, copper-based alloy) formed on the insulating layer. , Made of an iron-based alloy).

  Examples of the laminating step in the laminating step after the removing step of removing the protective film as necessary include a method of laminating by pressing the photosensitive resin composition layer on the circuit forming substrate while heating. The atmosphere during the lamination is not particularly limited, but the lamination is preferably performed under reduced pressure from the viewpoint of adhesion and followability. The surface to be laminated is usually the surface of the conductor layer of the circuit forming substrate, but may be a surface other than the conductor layer. The heating temperature of the photosensitive resin composition layer is preferably 70 to 130 ° C., the pressure bonding pressure is preferably about 0.1 to 1.0 MPa, and the ambient pressure is preferably 4000 Pa or less, There are no particular restrictions on these conditions. In addition, if the photosensitive resin composition layer is heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the circuit forming substrate in advance, but in order to further improve the laminating property, Pre-heat treatment of the substrate can also be performed.

  After the lamination is completed in this manner, a photocured portion is formed by irradiating a predetermined portion of the photosensitive resin composition layer with actinic rays in the exposure step. Examples of the method for forming the photocured portion include a method of irradiating an actinic ray in an image form through a negative or positive mask pattern called an artwork. At this time, when the support present on the photosensitive resin composition layer is transparent, it can be irradiated with actinic rays as it is, but when opaque, the photosensitive resin composition is removed after removing the support. Irradiate the layer with actinic rays.

  As the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or the like that can effectively emit ultraviolet rays can be used. Moreover, what can radiate | emit visible light effectively, such as a flood bulb for photography, a solar lamp, can also be used.

  Next, after exposure, when a support is present on the photosensitive resin composition layer, after removing the support, in the development process, a photosensitive resin other than the photocured portion by wet development, dry development, or the like. The composition layer is removed and developed to form a resist pattern. In the case of wet development, a developer corresponding to the photosensitive resin composition, such as an alkaline aqueous solution, an aqueous developer, or an organic solvent, is used, for example, by a known method such as spraying, rocking immersion, brushing, or scraping. develop. As the developer, a developer that is safe and stable and has good operability is used. For example, a dilute solution (1 to 5% by mass aqueous solution) of sodium carbonate at 20 to 50 ° C. is used.

The resist pattern obtained by the above-described forming method is preferably used for forming a flexible cured resin on a film-like substrate, and is used as a permanent mask formed on the film-like substrate. It is more preferable. For example, when used as an FPC coverlay, it is preferable to perform ultraviolet irradiation or heating with a high-pressure mercury lamp for the purpose of improving solder heat resistance, chemical resistance, etc., as the FPC coverlay after the development step. . In the case of irradiating ultraviolet rays, the irradiation amount can be adjusted as necessary. For example, the irradiation can be performed at an irradiation amount of about 0.2 to 10 J / cm ² . Moreover, when heating a resist pattern, it is preferable to carry out in the range for about 15 to 90 minutes in the range of about 100-170 degreeC. Furthermore, ultraviolet irradiation and heating can be performed at the same time, and after either one is performed, the other can be performed. When performing ultraviolet irradiation and heating simultaneously, it is more preferable to heat to 60 to 150 ° C. from the viewpoint of effectively imparting solder heat resistance, chemical resistance and the like.

  This cover lay serves as a protective film for the wiring after soldering the substrate, and has excellent flexibility, insulation, etc., and thus is effective as a permanent mask for FPC.

  The substrate provided with the resist pattern (coverlay) in this manner is then mounted with a component such as an LSI (for example, soldering) and mounted on an electronic device such as a camera.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  A modified epoxy resin as component (A) was prepared by the following method.

  First, 48.8 parts by mass of sebacic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 10.0 parts by mass of cyclohexanone, 10.0 parts by mass of toluene were added to a flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube. Then, 4.0 parts by mass of dimethylparatoluidine (manufactured by Samsung Chemical Co., Ltd.) was charged and stirred while being heated to 140 ° C. while blowing nitrogen gas. Next, 36.2 parts by mass of trimethylhexamethylene diisocyanate (manufactured by Huls Japan, trade name “VESTANATM TMDI”) was added dropwise, and the mixture was kept warm for 2 hours. Furthermore, the amide group containing dibasic acid was obtained by heating to 150 degreeC and making it heat-retain for 4 hours. Subsequently, this amide group-containing dibasic acid was diluted with 60 parts by mass of cyclohexanone. The obtained amide group-containing dibasic acid had a weight average molecular weight of 760, a solid content of 52.0% by mass, and an acid value of 129 mgKOH / g.

  Next, in a flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube, bisphenol A type epoxy resin (Epicoat 1001, manufactured by Japan Epoxy Resin, epoxy equivalent 479 g / eq, trade name) 182.7 mass Part, 64.0 parts by mass of cyclohexanone and 30.0 parts by mass of toluene were added, and the mixture was stirred while being heated to 130 ° C. while blowing nitrogen gas, whereby the water contained in the epoxy resin was refluxed and dehydrated. Next, 23.4 parts by mass of the amide group-containing dibasic acid (solid content 52.0% by mass) obtained above, 32.5 parts by mass of tetrahydrophthalic acid (manufactured by Nippon Nippon Chemical Co., Ltd.), and dimethyl paratoluidine 1.8 parts by mass (manufactured by Samsung Chemical Co., Ltd.) was added, and kept at 140 ° C. for 4 hours. Then, 108.0 parts of tetrahydrophthalic anhydride (manufactured by Shin Nippon Rika Co., Ltd.) was added and kept at 120 ° C. for 3 hours to obtain a modified epoxy resin as component (A). Thereafter, the modified epoxy resin was diluted with 162.0 parts of methyl ethyl ketone. The obtained modified epoxy resin had a weight average molecular weight of 35,000, a solid content of 56.0% by mass, and an acid value of 128 mgKOH / g. Moreover, IR spectrum of the obtained modified epoxy resin is shown in FIG. The IR spectrum was measured by “FTS135” (manufactured by Digilab Japan).

The weight average molecular weight of the amide group-containing dibasic acid and the modified epoxy resin (measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve) was measured under the following conditions. .
(GPC conditions)
Pump: Hitachi L-6000 type [manufactured by Hitachi, Ltd.]
Detector: Hitachi L-4000 UV [manufactured by Hitachi, Ltd.]
Column: Gelpack GL-S300MDT-5 (2) (manufactured by Hitachi Chemical Co., Ltd., trade name)
Column size: 8mmφ × 300mm
Eluent: DMF / THF = 1/1 + 0.06M phosphoric acid + 0.06M lithium bromide
Sample concentration: 5 mg / 1 mL
Injection volume: 5 μL
Pressure: 35 kgf / cm ²
Flow rate: 1.0 mL / min

  Next, a urethane resin as a constituent material of the component (B) was prepared by the following method. First, after introducing air into a flask equipped with a stirrer, reflux condenser, thermometer, and air introduction tube, polycarbonate diol (Placcel CD205PL, manufactured by Daicel Chemical Industries, Ltd., weight average molecular weight 500, trade name) 196.8 mass Parts, dimethylol butanoic acid (manufactured by Mitsubishi Chemical Corporation) 58.3 parts by mass, diethylene glycol (manufactured by Nisso Maruzen Chemical Co., Ltd.) 37.6 parts by mass, 1,4-cyclohexanedimethanol monoacrylate (manufactured by Mitsubishi Chemical Corporation) 148. 1 part by mass, p-methoxyphenol (manufactured by Wako Pure Chemical Industries, Ltd.) 0.55 parts by mass, dibutyltin laurate (manufactured by Tokyo Fine Chemical Co., Ltd., L101) 0.55 parts by mass and methyl ethyl ketone 110.2 parts by mass The temperature was raised to 65 ° C. with stirring.

  Next, 305.9 parts by weight of trimethylhexamethylene diisocyanate (manufactured by Huls Japan, trade name “VESTANATM TMDI”) was charged into the dropping container, and the reaction was continued for 3 hours while maintaining the reaction container temperature at 65 ± 3 ° C. It was dripped uniformly into the container. After the completion of the dropping, the dropping container was washed with 76.5 parts by mass of methyl ethyl ketone, and the washing liquid was put into the reaction container as it was. The mixture was further kept warm for 2 hours with stirring, and then the reaction vessel temperature was raised to 75 ° C.

  Thereafter, stirring and heating were continued at 75 ± 3 ° C. until the disappearance of the peak of the infrared absorption spectrum indicating the isocyanate group could be confirmed using an infrared spectrophotometer. After raising the temperature to 75 ° C., the peak of the infrared absorption spectrum based on the isocyanate group disappeared in about 6 to 8 hours. After confirming the disappearance of this peak, the reaction vessel temperature was lowered to 60 ° C., 9.3 parts by mass of methanol was added, and the mixture was kept at 60 ± 3 ° C. for 30 minutes. And 56.4 mass parts of methyl ethyl ketone was added, and the transparent solution containing a urethane resin was obtained. This is designated as resin (2). The urethane resin had a solid content of 75.6%, an acid value of 22.2 mgKOH / g, and a viscosity of 1810 mPa · s.

(Examples 1 and 2, Comparative Examples 1 and 2)
First, the photosensitive resin composition solution was obtained by mixing each component shown in Table 1 by the compounding ratio (mass basis) of the solid content shown there. In the table, resin (1) is a 65% by mass carbitol acetate / solvent naphtha solution of acid-modified bisphenol A type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., trade name “ZAR-1035”). Resin (3) is bisphenol A polyoxyethylene dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “BPE-10”), and component (C) is 2-benzyl-2-dimethylamino-1- (4-Morferinophenyl) -butanone-1 (manufactured by Ciba Specialty Chemicals, trade name “I-369”), BL3175 is a methyl ethyl ketone oxime block of isocyanurate based on hexamethylene diisocyanate as a base isocyanate It is a 75 mass% methyl ethyl ketone solution (manufactured by Sumika Bayer Urethane Co., Ltd., trade name “BL3175”).

  Subsequently, these photosensitive resin composition solutions are separately and uniformly applied onto a 16 μm-thick polyethylene terephthalate film (manufactured by Teijin Ltd., trade name “G2-16”) as a support layer, thereby photosensitive resin composition. A layer was formed and dried for about 10 minutes at 100 ° C. using a hot air convection dryer. The film thickness after drying of the photosensitive resin composition layer was 25 μm.

  Subsequently, on the surface of the photosensitive resin composition layer opposite to the side in contact with the support layer, a polyethylene film (manufactured by Tamapoly Co., Ltd., trade name “NF-13”) is bonded as a protective film, and photosensitive Got the element.

  And the copper surface of the board | substrate for flexible printed wiring boards (Nikkan Kogyo company make, brand name "F30VC1") which laminated | stacked 18-micrometer-thick copper foil on the polyimide base material was grind | polished with the abrasive brush, and it dried after washing with water. Using a continuous vacuum laminator (manufactured by Hitachi Chemical Co., Ltd., trade name “HLM-V570”) on this flexible printed wiring board substrate, a heat shoe temperature of 100 ° C., a laminating speed of 0.5 m / min, and a pressure of 4000 Pa or less, Under the condition of a pressure bonding pressure of 0.3 MPa, the obtained photosensitive element was laminated while peeling the polyethylene film to obtain a laminate for evaluation.

[Evaluation of light sensitivity]
On the obtained laminate for evaluation, a photo tool having a stove 21-step tablet as a negative was brought into close contact, and an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. was used. The exposure was performed with an energy amount such that the number of steps remaining after development was 8.0. Then, after leaving still at normal temperature for 1 hour and peeling a PET film, it developed by spraying 1 mass% sodium carbonate aqueous solution of 30 degreeC for 60 second, and heated (dried) at 80 degreeC for 10 minutes. The above-mentioned energy amount was used as a numerical value for evaluating photosensitivity. The lower this value, the higher the photosensitivity. The results are shown in Table 2.

[Resolution evaluation]
A phototool having a stove 21-step tablet and a phototool having a wiring pattern with a line width / space width of 30/30 to 200/200 (unit: μm) as a negative for resolution evaluation are provided on the evaluation laminate. Using the above-described exposure apparatus, the exposure was performed with an energy amount such that the number of remaining steps after development of the stove 21-step tablet was 8.0. Then, after leaving still at normal temperature for 1 hour and peeling a PET film, it developed by spraying 1 mass% sodium carbonate aqueous solution of 30 degreeC for 60 second, and heated (dried) at 80 degreeC for 10 minutes. Here, the resolution was evaluated based on the smallest value (unit: μm) of the space width between the line widths in which a rectangular resist shape was obtained by development processing. It shows that it is excellent in the resolution, so that this value is small. The results are shown in Table 2.

[Evaluation of coating properties]
The obtained laminate for evaluation was not exposed to light, but the polyethylene terephthalate on the laminate was peeled off, the finger was lightly pressed against the surface of the coating film, and the degree of sticking to the finger was evaluated according to the following criteria. That is, “○” indicates that sticking to the finger is not or hardly recognized, and “X” indicates that sticking to the finger is recognized. The results are shown in Table 2.

Furthermore, on the obtained laminate for evaluation, a phototool having a 21-step stove tablet and a phototool having a wiring pattern as a negative for coverlay reliability evaluation are used, and the exposure machine described above is used. Then, the exposure was performed with an energy amount such that the number of remaining steps after development of the stove 21-step tablet was 8.0. Next, after standing at room temperature for 1 hour, the polyethylene terephthalate on the laminate was peeled off, spray development was performed under the same developer and development conditions as in the photosensitivity evaluation, and heating (drying) at 80 ° C. for 10 minutes. did. Subsequently, ultraviolet rays were irradiated with an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further subjected to heat treatment at 160 ° C. for 60 minutes to obtain an evaluation FPC having a cover lay. It was.

[Evaluation of solder heat resistance]
After applying a rosin flux (trade name “MH-820V”, manufactured by Tamura Kaken Co., Ltd.) to the FPC for evaluation obtained as described above, it was immersed in a solder bath at 260 ° C. for 30 seconds for soldering. Went. In this way, the crack generation state of the coverlay on the solder-plated FPC and the degree of lift and peeling of the coverlay from the substrate were visually observed and evaluated according to the following criteria. That is, the case where no cracks in the cover lay were observed and the cover lay was not lifted or peeled off was indicated as “◯”, and the case where any of them was recognized as “X”. The results are shown in Table 2.

[Evaluation of folding resistance (flexibility)]
The obtained FPC for evaluation was folded 180 ° by goblet folding, the crack generation state in the coverlay at that time was visually observed, and evaluated according to the following criteria. That is, the case where no crack was found in the coverlay was “◯”, and the case where a crack was found was “x”. The results are shown in Table 2.

  As is apparent from Table 2, it was found that the laminates using the photosensitive resin compositions of Examples 1 and 2 were sufficiently excellent in photosensitivity, resolution, and coating properties. Moreover, it was confirmed that FPC obtained using these laminated bodies is sufficiently excellent in solder heat resistance and flexibility.

FIG. 1 is a diagram showing an IR spectrum of the modified epoxy resin obtained in the examples.

Claims (13)

The following general formula (1);

[Wherein, R ¹ represents a divalent organic group which is a diglycidyl ether type epoxy compound residue, and R ² represents the following general formula (2);

(In the formula, R ⁴ represents a divalent organic group that is a diisocyanate compound residue, R ⁵ represents a divalent organic group that is a dibasic acid residue, and m represents an integer of 1 or more.)
Represents a group represented by
R ³ is a hydrogen atom or the following general formula (3);

(In the formula, R ⁶ represents an acid anhydride residue.)
The group represented by these is shown. ]
A modified epoxy resin comprising a structural unit represented by: A preparation step of preparing a first intermediate product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid;
A first step of obtaining a second intermediate product by a polymerization reaction of a diglycidyl ether type epoxy compound and the first intermediate product;
A modified epoxy resin obtained by a method for producing a modified epoxy resin comprising a second step of adding an acid anhydride to the second intermediate product. The modified epoxy resin according to claim 2, wherein a dibasic acid is further reacted in the polymerization reaction of the first step. The dibasic acid is a dicarboxylic acid;
The modified epoxy resin according to any one of claims 1 to 3, wherein the modified epoxy resin has a chain structure by an ester bond formed by a reaction between a carboxyl group and a glycidyl group in the molecule. The modified epoxy resin according to any one of claims 1 to 4, which has a weight average molecular weight of 10,000 to 70,000. The modified epoxy resin according to any one of claims 1 to 5, which has an acid value of 70 to 150 mgKOH / g. A preparation step of preparing a first intermediate product obtained by a polymerization reaction of a diisocyanate compound and a dibasic acid;
A first step of obtaining a second intermediate product by a polymerization reaction of a diglycidyl ether type epoxy compound and the first intermediate product;
And a second step of adding an acid anhydride to the second intermediate product. The method for producing a modified epoxy resin according to claim 7, wherein a dicarboxylic acid is used as the dibasic acid. The method for producing a modified epoxy resin according to claim 7 or 8, wherein, in the first step, the polymerization reaction is performed by using a tertiary amine having a pKa of 9.0 or less as a catalyst. (A) The modified epoxy resin according to any one of claims 1 to 6, (B) a photopolymerizable compound having at least one ethylenically unsaturated group in the molecule, and (C) a photopolymerization initiator. And a photosensitive resin composition characterized by comprising: The photosensitive resin composition according to claim 10, which is used for forming a flexible cured resin on a film-like substrate. It is used for permanent mask formation of a flexible printed wiring board, The photosensitive resin composition of Claim 10 or 11 characterized by the above-mentioned. A photosensitive element comprising: a support; and a photosensitive resin composition layer comprising the photosensitive resin composition according to any one of claims 10 to 12 formed on the support. .

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