JP2011116849A - New reactive flame retardant and utilization thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition and typical utilization thereof, the photosensitive resin composition being obtained without using a halogen-based flame retardant but by using a reactive flame retardant of simultaneously achieving various physical properties, such as heat resistance, hydrolysis resistance, processability (including solvent solubility), and adhesion; and photosensitivity; flame retardancy; pliability; flexibility; and sufficient mechanical strength, and sufficiently dealable with downsizing and weight reduction of electronic parts in electronic equipment. <P>SOLUTION: The reactive flame retardant containing (a) phosphazene structure, (b) a photosensitive group, and (c) a urethane bond in a molecule is used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel reactive flame retardant and use thereof. More specifically, for example, a phosphazene compound having a secondary hydroxyl group obtained by reacting a phenolic hydroxyl group of a phosphazene compound having a phenolic hydroxyl group with an epoxy compound containing an unsaturated double bond is further converted to an isocyanate compound. It is related with the novel reactive flame retardant obtained by making it react with, the photosensitive resin composition excellent in the various characteristics after hardening, and its utilization.

  In recent years, as electronic devices have higher functionality, higher performance, smaller size, and lighter weight, high reliability is required for electronic components used in these electronic devices. Flame resistance is required.

  As a general method for realizing flame retardancy, there is a method of mixing a halogen-containing compound. For example, there is a photosensitive dry film resist produced by curing a photosensitive resin composition containing a brominated flame retardant (see, for example, Patent Document 1). However, the photosensitive dry film resist described in Patent Document 1 contains a brominated flame retardant, and the flame retardant containing halogen may adversely affect the environment. In addition, flame retardants containing halogen have a large environmental impact, and therefore, efforts to make them non-halogen (halogen-free) have become a global trend. For this reason, examination of a halogen-free flame retardant is advanced instead of a brominated flame retardant (for example, refer to patent documents 2). Known halogen-free flame retardants include nitrogen-based, phosphorus-based, inorganic compounds, and hydrates of phosphate esters, red phosphorus, and metal oxides.

  In recent years, a flame retardant using a resin to which a silicone compound is added has been studied (for example, see Patent Document 3). In addition, phosphazene compounds have been studied as flame retardants and are known to exhibit a high flame retardancy imparting effect. Among these, in order to impart flame retardancy to the resin, it is known to add a phosphazene compound to the resin (see, for example, Patent Document 4). Patent Document 4 discloses a photosensitive resin composition in which a phosphazene compound is blended with a polycarbonate resin or the like. The phosphazene compound is excellent in the effect of improving the flame retardancy, and has the advantage that the load on the environment is small because it is a halogen-free flame retardant.

  In addition, a reactive flame retardant that can efficiently form a cured film having sufficient flame retardancy with high resolution has been studied (for example, see Patent Document 5). Reactive flame retardant has the advantage that flame retardant bleed-out on the surface of the cured film can be suppressed by the reaction of the reactive group of the flame retardant with the photosensitive resin, and the flame retardancy can be improved. Yes.

JP 2001-335619 A JP 2002-235001 A JP 2001-40219 A JP-A-11-181268 JP-A-2005-513241

  However, when nitrogen-based, phosphorus-based, or inorganic compounds are used as halogen-free flame retardants, nitrogen-based compounds generally have an effect on resin curability, and phosphorus-based compounds have effects such as reduced moisture resistance. Is a difficult situation.

  In addition, phosphoric acid esters and red phosphorus may be hydrolyzed to generate phosphoric acid, which tends to cause a decrease in electrical insulation. Metal oxides tend to exhibit a decrease in flexibility of the resin composition, and are difficult to use as photosensitive resins because they scatter and absorb light.

  Moreover, even if it is a case where resin which added the silicone compound is used as a flame retardant, the kind of resin which can exhibit a flame-retardant effect is very limited. Furthermore, very few flame retardants with a silicone compound added alone have a large flame retardant effect, and even if they are relatively effective, a large amount of silicone compound is added to meet strict flame retardant standards. There is a need to. As a result, other necessary characteristics of the resin are adversely affected and disadvantageous in terms of cost, which is not practical.

  Even when a phosphazene compound is used as a flame retardant, when a resin mixed with the conventional phosphazene compound is used in a photosensitive resin composition or the like, the phosphazene compound is precipitated on the surface (bleeding). (Or juicing), and the physical properties of the resin are lowered. For example, conventional propoxylated phosphazenes and the like are in a liquid state, and thus there is a problem that the adhesiveness of the photosensitive resin composition cured after being processed at a high temperature is significantly lowered.

  In addition, when a cured film formed from the photosensitive resin composition described in Patent Document 5 is used as a surface protective film for a flexible circuit board, the photosensitive resin composition contains a polyimide resin or a polyimide precursor. Compared with the case where the cured film formed from the above is used, the cured film becomes fragile and lacks flexibility, and the cured film has a large shrinkage in curing, and the flexible circuit board may be greatly warped.

  The present invention has been made in view of the above problems, and its purpose is to use various properties such as heat resistance, hydrolysis resistance, processability (including solvent solubility), and adhesiveness without using a halogen-based flame retardant. It is possible to achieve both physical properties, photosensitivity, flame retardancy, flexibility, flexibility, and sufficient mechanical strength, and it can react well to miniaturization and weight reduction of electronic components in electronic devices. The object is to provide a flame retardant, a photosensitive resin composition using the reactive flame retardant, and a typical use thereof.

  As a result of diligent research to solve the above problems, the inventors of the present application, for example, a phosphazene compound having a secondary hydroxyl group obtained by reacting a phenoxyphosphazene compound with an epoxy compound containing an unsaturated double bond, Furthermore, it is a phosphazene compound obtained by reacting with an isocyanate compound, and a phosphazene compound containing (a) a phosphazene structure, (b) a photosensitive group, and (c) a urethane bond in the molecule as a reactive flame retardant. In particular, when the phosphazene compound is used as a flame retardant for a photosensitive resin composition, the balance of flame retardancy, flexibility, flexibility, photosensitivity, and other physical properties can be made excellent. The headline and the present invention have been completed.

  That is, this invention is a reactive flame retardant characterized by containing (a) a phosphazene structure, (b) a photosensitive group, and (c) a urethane bond in the molecule.

  The reactive flame retardant is characterized in that (b) the photosensitive group is a non-conjugated group.

  The reactive flame retardant is characterized in that (b) at least one photosensitive group is selected from a vinyl group, an acryloyl group, and a methacryloyl group.

  In addition, the reactive flame retardant is represented by the following general formula (1)

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₃ represent a divalent organic group, R 2 represents a phenyl group or a hydroxyphenyl group, and R ₄ represents a monovalent organic group.)
And a cyclic phenoxyphosphazene having a secondary hydroxyl group represented by the following general formula (2)

(In the formula, n represents an integer of 3 to 25, R ₆ and R ₈ represent a divalent organic group, R ₇ represents a phenyl group or a hydroxyphenyl group, and R ₉ represents a monovalent organic group.)
At least one hydroxyl group of the chain phenoxyphosphazene compound having a secondary hydroxyl group represented by the following general formula (3):

(In the formula, R ₅ represents a divalent organic group.)
It is obtained by making the diisocyanate compound shown by react, It is a reactive flame retardant characterized by the above-mentioned.

  The cyclic phenoxyphosphazene compound having a secondary hydroxyl group and / or the chain phenoxyphosphazene compound having a secondary hydroxyl group is represented by the following general formula (4).

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₂ represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
A cyclic phenoxyphosphazene compound represented by the following general formula (5):

(In the formula, n represents an integer of 3 to 25, R ₆ and R ₇ represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
And the phenolic hydroxyl group of the chain phenoxyphosphazene compound represented by the following general formula (6)

(In the formula, R ₁₀ represents a divalent organic group, and R ₄ represents a monovalent organic group.)
A reactive flame retardant obtained by reaction with an epoxy compound having an unsaturated double bond represented by formula (1).

  Another invention of the present invention is a photosensitive resin composition comprising at least the reactive flame retardant, (A) a photosensitive resin, and (B) a photopolymerization initiator.

  Another invention of the present invention is a photosensitive resin composition solution obtained by dissolving the above photosensitive resin composition in an organic solvent.

  Another invention of the present invention is a resin film obtained by applying the photosensitive resin composition solution to a substrate surface and then drying.

  Another invention of the present invention is a cured film obtained by curing the resin film.

  Another invention of the present invention is a printed wiring board with a cured film in which the cured film is coated on a printed wiring board.

  The reactive flame retardant in the present invention contains (a) a phosphazene structure, (b) a photosensitive group, and (c) a urethane bond in the molecule, so that it has photosensitivity, flame retardancy, flexibility, heat resistance, good It is possible to achieve both flexibility and sufficient mechanical strength, and express characteristics that it can sufficiently cope with downsizing and weight reduction of electronic components in electronic devices. In addition, since the photosensitive resin composition in the present invention has a structure containing a reactive flame retardant, the resulting cured film is rich in flexibility, electrical insulation reliability, solder heat resistance, organic solvent resistance, difficulty Excellent flame retardancy, good physical properties, small warpage after curing, excellent adhesion to sealant, and no bleed out of flame retardant component from cured film. Therefore, the photosensitive resin composition of the present invention can be used for protective films of various circuit boards and exhibits excellent effects.

Schematic diagram measuring the amount of warping of the film

  Hereinafter, the present invention will be described in detail.

<Reactive flame retardant>
The reactive flame retardant in the present invention has a reactive group capable of reacting with at least one other compound in the substance, and when added to a flammable substance such as plastic, wood, fiber, etc., the substance is difficult. It is a substance that can impart flammability.

  In particular, when the reactive flame retardant is a phosphorus compound having a phosphorus atom in the molecule, no harmful gas is generated during combustion.

  Examples of the reactive group include a thermosetting group such as a hydroxyl group, an epoxy group, a carboxyl group, an amino group, and an isocyanate group, a photosensitive group such as a vinyl group and a (meth) acryloyl group, and the like. Among them, when the reactive flame retardant has a photosensitive group as a reactive group, a part of the photosensitive resin composition containing the reactive flame retardant is irradiated with energy such as UV and photocured. Since the photosensitive group in the flame retardant reacts with the components in the photosensitive resin composition to form a three-dimensional network structure, the heat resistance, chemical resistance, and electrical insulation reliability of the resulting cured film are improved.

  Here, the reactive flame retardant of the present invention is characterized by containing (a) a phosphazene structure, (b) a photosensitive group, and (c) a urethane bond, and the present inventors are excellent in various properties. I have guessed that this may be due to the following reasons. That is, (a) the phosphazene structure is excellent in compatibility with the photosensitive resin described later, and further, a cured film obtained by curing the photosensitive resin composition containing the reactive flame retardant. High flame retardancy can be imparted without impairing heat resistance.

  In addition, (b) the photosensitive group reacts with the components in the photosensitive resin composition to form a three-dimensional network structure, so that the bleed-out of the flame retardant component from the cured film can be suppressed, and the flame retardancy Can be further improved. In addition, the heat resistance, chemical resistance, and electrical insulation reliability of the resulting cured film are improved.

  Moreover, the heat resistance, water resistance, and mechanical strength of the obtained cured film can be improved by (c) urethane bond. Furthermore, it is speculated that the flexibility and flexibility of the resulting cured film can be improved by reducing the crystallinity of the reactive flame retardant.

  The following (a) phosphazene structure, (b) photosensitive group, (c) urethane bond, method for synthesizing reactive flame retardant, (A) photosensitive resin, (B) photopolymerization initiator, other components, and reaction A method for mixing the flame retardant, (A) and (B) will be described.

<(A) Phosphazene structure>
The (a) phosphazene structure in the present invention is a structure having phosphorus and nitrogen as constituent elements and a double bond. Among them, the above (a) phosphazene structure has the following general formula (7).

(In the formula, R and R ′ represent a monovalent or higher-valent organic group.)
It is preferable in that it can improve the compatibility with a photosensitive resin or the like described later, and the phenoxyphosphazene structure is improved in compatibility with a photosensitive resin or the like described later. It is particularly preferable in that high flame retardancy can be imparted without impairing the heat resistance of the resulting cured film.

  Although the manufacturing method of a phenoxyphosphazene structure is not specifically limited, For example, following formula (8)

As a raw material phosphazene compound, a linear or chain dichlorophosphazene compound represented by the following general formula (9)

(In the formula, M represents an alkali metal.)
And / or the following general formula (10)

(In the formula, M represents an alkali metal.)
It can manufacture by making the alkali metal phenolate shown by react. In the alkali metal phenolate represented by the general formula (10), the position of the alkyloxy group (methoxy group) is not particularly limited.

  By the above reaction, a phenyl group and / or a methoxyphenyl group can be introduced into the structure represented by the formula (8).

  The details of the reaction conditions are not particularly limited. For example, the compound obtained by the above reaction can be reacted with pyridine hydrohalide or boron tribromide to give a methoxyphenyl group. Can be deprotected and converted to a hydroxyl group.

<(B) Photosensitive group>
The (b) photosensitive group in the present invention is a reactive group that causes a chemical reaction when irradiated with light energy. Among these, it is preferable to have at least one unsaturated double bond in the molecule. Furthermore, the unsaturated double bond includes a vinyl group (CH ₂ ═CH— group), an acryloyl group (CH ₂ ═CHCO—O— group), or a methacryloyl group (CH ₂ ═C (CH ₃ ) CO— O-group), which can be used alone or in combination of two or more. In particular, in the reactive group in the present invention, when the photosensitive group is a (meth) acryloyl group and is contained in the molecule, the photosensitivity of the reactive flame retardant is improved, and the photosensitive resin composition is reduced in energy. It is preferable because it can be cured by the above method. The compatibility with the photosensitive resin can be remarkably improved by this photosensitive group. Furthermore, some of the photosensitive groups in the flame retardant react with the components in the photosensitive resin composition to form a three-dimensional network structure, so that the resulting cured film has heat resistance, chemical resistance, and electrical insulation reliability. Is preferable. Moreover, in the cured film obtained, the flame retardant can be made difficult to precipitate (bleed out) on the surface, and the flame retardancy can be further improved.

<(C) Urethane bond>
The (c) urethane bond in the present invention is the following general formula (11).

It is a structure shown by. Although the manufacturing method of a urethane bond is not specifically limited, For example, it synthesize | combines by reaction of an isocyanate group containing compound and a hydroxyl group containing compound. By this urethane bond, the heat resistance and water resistance of the obtained cured film can be improved. Furthermore, when the crystallinity of the reactive flame retardant is lowered, the flexibility and flexibility of the obtained cured film can be improved.

<Method for synthesizing reactive flame retardant>
Although the manufacturing method of the reactive flame retardant in this invention is not specifically limited, For example, it can manufacture with the following method.

  First, the following general formula (4)

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₂ represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
A cyclic phenoxyphosphazene compound represented by the following general formula (5):

(In the formula, n represents an integer of 3 to 25, R ₆ and R ₇ represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
And the phenolic hydroxyl group of the chain phenoxyphosphazene compound represented by the following general formula (6)

(In the formula, R ₁₀ represents a divalent organic group, and R ₄ represents a monovalent organic group.)
By reacting with an epoxy compound having an unsaturated double bond represented by the following general formula (1)

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₃ represent a divalent organic group, R ₂ represents a phenyl group or a hydroxyphenyl group, and R ₄ represents a monovalent organic group.)
And a cyclic phenoxyphosphazene having a secondary hydroxyl group represented by the following general formula (2)

(In the formula, n represents an integer of 3 to 25, R ₆ and R ₈ represent a divalent organic group, R ₇ represents a phenyl group or a hydroxyphenyl group, and R ₉ represents a monovalent organic group.)
A chain phenoxyphosphazene having a secondary hydroxyl group represented by

  By using the above cyclic phenoxyphosphazene compound and / or chain-like phenoxyphosphazene compound, flame resistance and high solder heat resistance are imparted to the obtained cured film without using a halogen compound, and at the same time excellent electrical insulation Is also particularly preferable.

  The epoxy compound having an unsaturated double bond used in the present invention is not particularly limited as long as it is a compound having an epoxy group and an unsaturated double bond in the molecule. Specifically, for example, for example, glycidyl Examples include compounds represented by methacrylate, glycidyl acrylate, allyl glycidyl ether, and glycidyl vinyl ether. These compounds may be used alone or in combination of two or more.

  The reaction of the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound with an epoxy compound having an unsaturated double bond is not particularly limited, and can be performed, for example, as follows.

  First, the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound and an epoxy compound having an unsaturated double bond are dissolved in an organic solvent. As the organic solvent, preferably, aromatics such as benzene, toluene and xylene; ethers such as ether, tetrahydrofuran and dioxane; N-substituted amides such as N, N-dimethylformamide; and the like can be used. These organic solvents may be used alone or in combination of two or more. In addition, when the said cyclic | annular phenoxyphosphazene compound and / or the said chain | strand-shaped phenoxyphosphazene compound melt | dissolve at reaction temperature, it can carry out without a solvent.

  A solution in which the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound and the epoxy compound having an unsaturated double bond are dissolved is used in a temperature range from room temperature to the reflux temperature of the solvent, such as pyridine and triethylamine. The reaction is carried out in the presence of a tertiary amine for 1 to 20 hours. In the case of no solvent, the molten cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound and an epoxy compound having an unsaturated double bond are dissolved, and the solution is heated to room temperature or higher at the cyclic phenoxyphosphazene compound. And / or the reaction is carried out in the temperature range below the reflux temperature of the chain phenoxyphosphazene compound. In this reaction, a known stabilizer can be added.

  In the reaction, the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound and the epoxy compound having an unsaturated double bond are adjusted to adjust the reaction amount. All phenolic hydroxyl groups of the phenoxyphosphazene compound may be reacted with an epoxy compound having an unsaturated double bond.

  The amount of the epoxy compound having an unsaturated double bond is preferably 3 times mol or less with respect to the phenolic hydroxyl group of the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound. More preferably, it is less than or equal to 2 mol. Further, the lower limit of the amount of the epoxy compound having an unsaturated double bond may be determined by the amount of the unsaturated double bond introduced into the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound. The amount of unsaturated double bonds introduced into the phosphazene compound is preferably at least one per molecule of the phosphazene compound, and more preferably 1.2 or more. Therefore, it is preferable to add 1 mol or more of an epoxy compound having an unsaturated double bond, and more preferably 1.2 mol or more, per 1 mol of the cyclic phenoxyphosphazene compound and / or the chain phenoxyphosphazene compound.

  Subsequently, at least one hydroxyl group of the obtained cyclic phenoxyphosphazene having a secondary hydroxyl group and / or a chain phenoxyphosphazene compound having a secondary hydroxyl group, and the following general formula (3)

(In the formula, R ₅ represents a divalent organic group.)
The diisocyanate compound shown by is made to react.

  Examples of such diisocyanate compounds include diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3. '-Or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5, 2'- or 5,3'- or 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4 , 3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3 , 3'-Diisocyanate Diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2 , 6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4 '-[2,2-bis (4-phenoxyphenyl) propane] diisocyanate Compound, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, etc., hexamethylene diisocyanate , Trimethylhexamethylene diisocyanate, aliphatic diisocyanate compounds and the like such as lysine diisocyanate, and these may be used alone or in combinations of two or more. Use of these is preferable for increasing the heat resistance of the resulting cured film.

  Examples of the diisocyanate compound include diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, and norbornene diisocyanate. It is particularly preferable to use Thereby, it is preferable at the point which can improve the heat resistance of the cured film obtained, and water resistance further.

  Moreover, in order to improve the developability of the photosensitive resin composition, tolylene-2,6-diisocyanate, tolylene-2,4-diisocyanate and 1,6-hexamethylene diisocyanate are preferably used as the diisocyanate compound. .

  Moreover, it is also preferable to use the terminal isocyanate compound obtained by making a diisocyanate compound and a diol compound react at the point which can further improve the softness | flexibility of an obtained cured film, flexibility, and mechanical strength.

  The method for reacting the cyclic phenoxyphosphazene having a secondary hydroxyl group and / or the chain phenoxyphosphazene having a secondary hydroxyl group with a diisocyanate compound is not particularly limited. For example, the reaction can be performed by the following method.

  First, the cyclic phosphazene having the secondary hydroxyl group and / or the chain phosphazene compound having the secondary hydroxyl group and the diisocyanate compound are dissolved in an organic solvent. As the organic solvent, preferably, aromatics such as benzene, toluene and xylene; ethers such as ether, tetrahydrofuran and dioxane; N-substituted amides such as N, N-dimethylformamide; and the like can be used. These organic solvents may be used alone or in combination of two or more. In addition, when the cyclic phosphazene having the secondary hydroxyl group and / or the chain phosphazene compound having the secondary hydroxyl group melt at the reaction temperature, the reaction can be carried out without solvent.

  A solution in which the cyclic phosphazene having the secondary hydroxyl group and / or the chain phosphazene compound having the secondary hydroxyl group and the diisocyanate compound are dissolved in a temperature range from room temperature to the reflux temperature of the solvent in pyridine triethylamine. In the presence of a tertiary amine such as 1 to 20 hours. In the absence of a solvent, the molten cyclic phosphazene having the secondary hydroxyl group and / or the chain phosphazene compound having the secondary hydroxyl group and the diisocyanate compound are dissolved, and the solution is heated to room temperature or higher at the reflux temperature. The reaction is carried out in the following temperature range. Thereby, the reactive flame retardant in this invention can be obtained. In this reaction, a known stabilizer can be added.

  In the above reaction, by adjusting the reaction amount of the cyclic phosphazene having the secondary hydroxyl group and / or the chain phosphazene compound having the secondary hydroxyl group and the diisocyanate, all the secondary hydroxyl groups are converted to isocyanate groups. You may make it react.

  The amount of the diisocyanate compound is preferably 2 mol or less with respect to the cyclic phosphazene having the secondary hydroxyl group and / or the hydroxyl group of the chain phosphazene compound having the secondary hydroxyl group. More preferably, it is less than or equal to 2 mol.

<(A) Photosensitive resin>
The (A) photosensitive resin used in the present invention is a resin in which a chemical bond is formed by (B) a photopolymerization initiator. Among these, a resin having at least one unsaturated double bond in the molecule is preferable. Furthermore, the unsaturated double bond includes a vinyl group (CH ₂ ═CH— group), a vinylene group (—CH═CH—), a vinylidene group (CH ₂ ═C <), an acryloyl group (CH ₂ ═CHCO—). O-group) or a methacryloyl group (CH ₂ ═C (CH ₃ ) CO—O— group) is preferable.

  Examples of the photosensitive resin (A) include bisphenol F EO modified (n = 2 to 50) diacrylate, bisphenol A EO modified (n = 2 to 50) diacrylate, and bisphenol S EO modified (n = 2 to 50). Diacrylate, bisphenol F EO modified (n = 2-50) dimethacrylate, bisphenol A EO modified (n = 2-50) dimethacrylate, bisphenol S EO modified (n = 2-50) dimethacrylate, 1,6-hexane Diol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, tetramethyl Propane tetraacrylate, tetraethylene glycol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, dipenta Erythritol hexamethacrylate, tetramethylolpropane tetramethacrylate, tetraethylene glycol dimethacrylate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, β-methacryloyloxyethyl hydrogen phthalate, β-methacryloyloxyethyl hydrogen succinate, 3-chloro-2- Hide Xylpropyl methacrylate, stearyl methacrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxy polyethylene glycol acrylate, β-acryloyloxyethyl hydrogen succinate, lauryl acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis [4- (Methacryloxyethoxy ) Phenyl] propane, 2,2-bis [4- (methacryloxy diethoxy) phenyl] propane, 2,2-bis [4- (methacryloxy polyethoxy) phenyl] propane, polyethylene glycol diacrylate, tripropylene glycol diacrylate, Polypropylene glycol diacrylate, 2,2-bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, 2-hydroxy-1-acryloxy-3-methacryl Roxypropane, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, methoxydipropylene glycol methacrylate, methoxytriethylene group Cole acrylate, nonylphenoxy polyethylene glycol acrylate, nonyl phenoxy polypropylene glycol acrylate, 1-acryloyloxypropyl-2-phthalate, isostearyl acrylate, polyoxyethylene alkyl ether acrylate, nonylphenoxyethylene glycol acrylate, polypropylene glycol dimethacrylate, 1,4 -Butanediol dimethacrylate, 3-methyl-1,5-pentanediol dimethacrylate, 1,6-mexanediol dimethacrylate, 1,9-nonanediol methacrylate, 2,4-diethyl-1,5-pentanediol di Methacrylate, 1,4-cyclohexanedimethanol dimethacrylate, dipropylene glycol diacrylate, Tricyclodecane dimethanol diacrylate, 2,2-hydrogenated bis [4- (acryloxy polyethoxy) phenyl] propane, 2,2-bis [4- (acryloxy polypropoxy) phenyl] propane, 2,4-diethyl -1,5-pentanediol diacrylate, ethoxylated tomethylolpropane triacrylate, propoxylated tomethylolpropane triacrylate, isocyanuric acid tri (ethane acrylate), pentathritol tetraacrylate, ethoxylated pentathritol tetraacrylate, propoxylation Pentathritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol polyacrylate, triallyl isocyanurate, glycidyl methacrylate, glycidyl ali Ether, 1,3,5-triacryloylhexahydro-s-triazine, triallyl1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, triallyl phosphate, arborbital, diallylamine, diallyldimethylsilane, diallyl Disulfide, diallyl ether, zalyl sialate, diallyl isophthalate, diallyl terephthalate, 1,3-dialyloxy-2-propanol, diallyl sulfide diallyl maleate, 4,4′-isopropylidene diphenol dimethacrylate, 4,4′-isopropyl Redene diphenol diacrylate and the like are preferable, but are not limited thereto. In particular, the repeating unit of EO (ethylene oxide) contained in one molecule of diacrylate or methacrylate is preferably in the range of 2-50, more preferably 2-40. By using an EO repeating unit in the range of 2 to 50, the solubility of the photosensitive resin composition in an aqueous developer typified by an alkaline aqueous solution is improved, and the development time is shortened. Furthermore, it is difficult for stress to remain in the cured film obtained by curing the photosensitive resin composition. For example, among the printed wiring boards, when laminated on a flexible printed wiring board based on a polyimide resin, curling of the printed wiring board is prevented. Features such as being able to be suppressed.

  In particular, it is particularly preferable to use the EO-modified diacrylate or dimethacrylate together with an acrylic resin having 3 or more acrylic groups or methacrylic groups in order to improve developability. For example, ethoxylated isocyanuric acid EO-modified triacrylate, Ethoxylated isocyanuric acid EO modified trimethacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol tri Acrylate, ethoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethyl Propanetetraacrylate, ditrimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, 2,2,2-trisacryloyloxymethyl ethyl succinic acid, 2,2, 2-trisacryloyloxymethylethylphthalic acid, propoxylated ditrimethylolpropane tetraacrylate, propoxylated dipentaerythritol hexaacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone modified tris- (2-acryloxyethyl) isocyanurate, Caprolactone-modified ditrimethylolpropane tetraacrylate, the following general formula (12)

(Where a + b = 6 and n = 12.)
A compound represented by the following general formula (13)

(Where a + b = 4 and n = 4)
A compound represented by formula (14):

A compound represented by the following general formula (15)

(Where m = 1, a = 2, b = 4, or m = 1, a = 3, b = 3, or m = 1, a = 6, b = 0, or m = 2, a = 6 B = 0.)
A compound represented by the following general formula (16)

(Where a + b + c = 3.6)
A compound represented by formula (17):

A compound represented by the following general formula (18)

(Where m · a = 3, a + b = 3, where “m · a” is the product of m and a)
An acrylic resin such as a compound represented by the formula is preferably used.

  In addition, hydroxyl groups, carbonyls in the molecular structure such as 2-hydroxy-3-phenoxypropyl acrylate, phthalic acid monohydroxyethyl acrylate, ω-carboxy-polycaprolactone monoacrylate, acrylic acid dimer, pentaerythritol tri and tetraacrylate Those having a group are also preferably used.

  In addition, any photosensitive resin such as an epoxy-modified acrylic (methacrylic) resin, a urethane-modified acrylic (methacrylic) resin, or a polyester-modified acrylic (methacrylic) resin may be used.

  In addition, although it is also possible to use 1 type as a photosensitive resin, using 2 or more types together is preferable when improving the heat resistance of the cured film after photocuring.

<(B) Photopolymerization initiator>
The (B) photopolymerization initiator in the present invention is a compound that is activated by energy such as UV and initiates / promotes the reaction of the photosensitive resin.

  Examples of the (B) photopolymerization initiator include Mihiras ketone, 4,4′-bis (diethylamino) benzophenone, 4,4 ′, 4 ″ -tris (dimethylamino) triphenylmethane, and 2,2 ′. -Bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-diimidazole, acetophenone, benzoin, 2-methylbenzoin, benzoin methyl ether, benzoin ethyl ether, Benzoin isopropyl ether, benzoin isobutyl ether, 2-t-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, methylanthraquinone, thioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 1- Hydroxycyclohexyl phenyl ketone, diacetylbenzyl, ben Zyldimethylketal, benzyldiethylketal, 2 (2′-furylethylidene) -4,6-bis (trichloromethyl) -S-triazine, 2 [2 ′ (5 ″ -methylfuryl) ethylidene]- 4,6-bis (trichloromethyl) -S-triazine, 2 (p-methoxyphenyl) -4,6-bis (trichloromethyl) -S-triazine, 2,6-di (p-azidobenzal) -4-methyl Cyclohexanone, 4,4′-diazidochalcone, di (tetraalkylammonium) -4,4′-diazidostilbene-2,2′-disulfonate, 2,2-dimethoxy-1,2-diphenylethane-1 -One, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2- Loxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-mol phorinopropan-1-one, 2 -Benzyl-2-dimethylamino-1- (4-molforinophenyl) -butane-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- 2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propane-1-ketone, bis (n5- 2,4-Cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -pheny ) Titanium, 1,2-octanonedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], iododium, (4-methylphenyl) [4- (2-methylpropyl) Phenyl] -hexafluorophosphate (1-), ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H- Carbazol-3-yl]-, 1- (O-acetyloxyome) and the like. The photopolymerization initiator is desirably selected as appropriate, and it is desirable to use a mixture of one or more.

<Organic solvent>
Examples of the organic solvent for dissolving the photosensitive resin composition in the present invention include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, methyl monoglyme (1,2-dimethoxyethane), methyl diglyme (bis (2-methoxy). Ether), methyltriglyme (1,2-bis (2-methoxyethoxy) ethane), methyltetraglyme (bis [2- (2-methoxyethoxyethyl)] ether), ethyl monoglyme (1,2- Symmetric glycol diethers such as diethoxyethane), ethyl diglyme (bis (2-ethoxyethyl) ether), butyl diglyme (bis (2-butoxyethyl) ether), γ-butyrolactone, methyl acetate, ethyl acetate, Isopropyl acetate, n-propyl acetate, butyl acetate , Propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate (also known as carbitol acetate, 2- (2-butoxyethoxy) ethyl acetate), diethylene glycol monobutyl ether acetate, 3-methoxybutyl acetate , Acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate, 1,3-butylene glycol diacetate, dipropylene glycol methyl ether, tripropylene glycol methyl Ether, propylene glycol n-propyl ether, dip Lopylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripyrene glycol n-propyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, 1,3-dioxolane, ethylene glycol monobutyl ether, diethylene glycol Examples include ethers such as monoethyl ether, diethylene glycol monobutyl ether, and ethylene glycol monoethyl ether, and these can be used alone or in combination of two or more. Among them, symmetric glycol diethers are particularly preferable because the solubility of the photosensitive resin composition is high.

  The organic solvent component in the photosensitive resin composition of the present invention is preferably 10 to 400 weights with respect to 100 parts by weight of the total of the reactive flame retardant component, (A) component, and (B) component of the present invention. Parts, more preferably 20 to 200 parts by weight, particularly preferably 40 to 100 parts by weight.

  It is preferable to adjust the amount of the organic solvent component within the above range because the viscosity and viscosity of the photosensitive resin composition can be adjusted within a range suitable for coating such as screen printing.

  When the organic solvent component is less than the above range, the viscosity of the photosensitive resin composition becomes very high, coating becomes difficult, and foam entrainment during coating and leveling properties may be inferior. Moreover, when there are more organic solvent components than the said range, the viscosity of the photosensitive resin composition will become very low, application | coating will become difficult and the circuit coverage may be inferior.

  The photosensitive resin composition of the present invention can further use a thermosetting resin as necessary.

<Thermosetting resin>
The thermosetting resin in the present invention is a compound that generates a crosslinked structure by heating and functions as a thermosetting agent. For example, thermosetting resins such as epoxy resin, bismaleimide resin, bisallyl nadiimide resin, acrylic resin, methacrylic resin, hydrosilyl cured resin, allyl cured resin, and unsaturated polyester resin; allyl on the side chain or terminal of the polymer chain A side chain reactive group type thermosetting polymer having a reactive group such as a group, a vinyl group, an alkoxysilyl group, and a hydrosilyl group can be used. The said thermosetting component, ie, a thermosetting resin, should just be used 1 type or in combination of 2 or more types as appropriate.

  Among these, it is more preferable to use an epoxy resin as the thermosetting resin. By containing an epoxy resin component, heat resistance can be imparted to a cured film obtained by curing the photosensitive resin composition, and adhesion to a conductor such as a metal foil or a circuit board can be imparted.

  The epoxy resin is a compound containing at least two epoxy groups in the molecule. For example, as a bisphenol A type epoxy resin, product names jER828, jER1001, jER1002, and ADEKA manufactured by Japan Epoxy Resin Co., Ltd. Trade names of Adeka Resin EP-4100E, Adeka Resin EP-4300E, trade names RE-310S and RE-410S manufactured by Nippon Kayaku Co., Ltd., trade names Epicron 840S, Epicron 850S, Epicron 1050 and Epicron 7050 manufactured by Dainippon Ink, Inc. The product names Epototo YD-115, Epototo YD-127, Epototo YD-128, and bisphenol F type epoxy resins manufactured by Toto Kasei Co., Ltd. are trade names jER806 and jER8 manufactured by Japan Epoxy Resin Co., Ltd. 7. Trade names Adeka Resin EP-4901E, Adeka Resin EP-4930, Adeka Resin EP-4950, manufactured by Adeka Co., Ltd., trade names RE-303S, RE-304S, RE-403S, RE-404S, manufactured by Nippon Kayaku Co., Ltd. Product names Epicron 830 and Epicron 835 manufactured by Nippon Ink Co., Ltd. Product names Epototo YDF-170, Epototo YDF-175S, Epototo YDF-2001, and Bisphenol S type epoxy resin manufactured by Toto Kasei Co., Ltd. Trade name Epiklon EXA-1514 manufactured by Japan, Hydrogenated bisphenol A type epoxy resin includes Japan Epoxy Resin Co., Ltd. trade names jERYX8000, jERYX8034, jERYL7170, ADEKA Co., Ltd. trade names Adeka Resin P-4080E, Dainippon Ink Co., Ltd. trade name Epicron EXA-7015, Toto Kasei Co., Ltd. trade name Epototo YD-3000, Epototo YD-4000D, biphenyl type epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd. Trade names jERYX4000, jERYL6121H, jERYL6640, jERYL6677, trade names NC-3000 and NC-3000H manufactured by Nippon Kayaku Co., Ltd., and phenoxy type epoxy resins include trade names jER1256, jER4250, jER4275, and naphthalene manufactured by Japan Epoxy Resins Co., Ltd. As the type epoxy resin, trade names “Epicron HP-4032”, “Epicron HP-4700”, “Epicron HP-4200” manufactured by Dainippon Ink Co., Ltd., “NC-” manufactured by Nippon Kayaku Co., Ltd. As 7000L, phenol novolac type epoxy resin, trade names jER152 and jER154 manufactured by Japan Epoxy Resin Co., Ltd., trade name EPPN-201-L manufactured by Nippon Kayaku Co., Ltd., trade name Epicron N- manufactured by Dainippon Ink Co., Ltd. 740, Epicron N-770, Toto Kasei Co., Ltd. trade name Epototo YDPN-638, Cresol novolac type epoxy resin, Nippon Kayaku Co., Ltd. trade names EOCN-1020, EOCN-102S, EOCN-103S, EOCN -104S, trade names manufactured by Dainippon Ink Co., Ltd. Epicron N-660, Epicron N-670, Epicron N-680, Epicron N-695, and Trisphenolmethane type epoxy resin are trade names of Nippon Kayaku Co., Ltd. EPPN-501H, EPP -501HY, EPPN-502H, dicyclopentadiene type epoxy resin, Nippon Kayaku Co., Ltd. trade name XD-1000, Dainippon Ink Co., Ltd. trade name Epicron HP-7200, amine type epoxy resin, Product names of Toto Kasei Co., Ltd. Epototo YH-434, Epototo YH-434L, and flexible epoxy resins include trade names jER871, jER872, jERYL7175, jERYL7217, manufactured by Dainippon Ink, Inc. As the name Epicron EXA-4850, urethane-modified epoxy resin, trade names of Adeka Resin EPU-6, Adeka Resin EPU-73, Adeka Resin EPU-78-11 manufactured by ADEKA Corporation, and ADE Co., Ltd. as ADE Co., Ltd. Trade name of A Adeka Resin EPR-4023, Adeka Resin EPR-4026, ADEKA RESIN EPR1309, Chelating-modified epoxy resin, ADEKA Corporation under the trade name Adeka Resin EP-49-10, and the like Adecaresin EP-49-20.

  Although it does not specifically limit as a hardening | curing agent of the said thermosetting resin in the photosensitive resin composition of this invention, For example, phenol resins, such as a phenol novolak resin, a cresol novolak resin, a naphthalene type phenol resin, an amino resin, and a urea resin , Melamine, dicyandiamide and the like, and these can be used alone or in combination of two or more.

  Further, the curing accelerator is not particularly limited, but for example, phosphine compounds such as triphenylphosphine; amine compounds such as tertiary amine, trimethanolamine, triethanolamine and tetraethanolamine; 1,8- Borate compounds such as diaza-bicyclo [5,4,0] -7-undecenium tetraphenylborate, imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-un Imidazoles such as decylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole; 2-methylimidazoline, 2- Ethyl imidazoline, 2 Imidazolines such as isopropylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline; 2,4-diamino-6- [2′-methylimidazolyl- ( 1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2 ′ Examples include azine-based imidazoles such as -ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, and these can be used alone or in combination of two or more.

  The thermosetting resin component in the photosensitive resin composition of the present invention is preferably 0.1 parts by weight based on 100 parts by weight of the total of the reactive flame retardant component, the (A) component, and the (B) component of the present invention. 5 to 100 parts by weight, more preferably 1 to 50 parts by weight, and particularly preferably 5 to 20 parts by weight.

  By adjusting the amount of the thermosetting resin component within the above range, the heat resistance, chemical resistance, and electrical insulation reliability of the cured film obtained by curing the photosensitive resin composition can be improved. preferable.

  When there are few thermosetting resin components than the said range, the heat resistance of the cured film obtained by hardening the photosensitive resin composition and electrical insulation reliability may be inferior. Moreover, when there are more thermosetting resin components than the said range, the cured film obtained by hardening the photosensitive resin composition becomes weak, it is inferior to a softness | flexibility, and the curvature of a cured film may also become large.

  In the photosensitive resin composition of the present invention, an inorganic filler can be used for the purpose of improving the adhesion and the hardness of the cured film. The inorganic filler is not particularly limited, and examples thereof include barium sulfate, barium titanate, talc, ultrafine anhydrous silica, synthetic silica, natural silica, calcium carbonate, magnesium carbonate, and aluminum oxide. It can be used alone or in combination of two or more.

  In the photosensitive resin composition of the present invention, additives such as an antifoaming agent, a leveling agent, a colorant, an adhesion imparting agent, and a polymerization inhibitor can be used as necessary. These additives are not particularly limited. For example, as an antifoaming agent, a silicon compound, an acrylic compound, as a leveling agent, a silicon compound, an acrylic compound, and as a colorant, a phthalocyanine compound, Examples of the azo compound, carbon black, titanium oxide, and adhesion imparting agent include silane coupling agents, triazole compounds, tetrazole compounds, triazine compounds, and polymerization inhibitors include hydroquinone and hydroquinone monomethyl ether. These can be used alone or in combination of two or more.

  The photosensitive resin composition of the present invention is obtained by uniformly mixing the above components. As a method of uniformly mixing, for example, a general kneading apparatus such as a three roll or bead mill apparatus may be used for mixing. Moreover, when the viscosity of a solution is low, you may mix using a general stirring apparatus.

  The photosensitive resin composition of the present invention can form a pattern as follows. First, the photosensitive resin composition is applied onto a substrate and dried to remove the organic solvent. The substrate can be applied by screen printing, roller coating, curtain coating, spray coating, spin coating using a spinner, or the like. The coating film (preferably having a thickness of 5 to 100 μm) is dried at 120 ° C. or lower, preferably 40 to 100 ° C. After drying, a negative photomask is placed on the dried coating film and irradiated with actinic rays such as ultraviolet rays, visible rays, and electron beams. Subsequently, the pattern can be obtained by washing out the unexposed portion with a developer using various methods such as shower, paddle, immersion, or ultrasonic wave. Since the time until the pattern is exposed varies depending on the spray pressure and flow velocity of the developing device and the temperature of the developer, it is preferable to find the optimum device conditions as appropriate.

  As the developer, an aqueous alkali solution is preferably used. The developer is water-soluble such as methanol, ethanol, n-propanol, isopropanol, N-methyl-2-pyrrolidone and the like. An organic solvent may be contained. Examples of the alkaline compound that gives the alkaline aqueous solution include hydroxides, carbonates, hydrogen carbonates, amine compounds, and the like of alkali metals, alkaline earth metals, or ammonium ions, specifically sodium hydroxide. , Potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisopropylammonium Hydroxide, N-methyldiethanolamine, N-ethyldiethanolamine, N, N-dimethylethanolamine, triethanolamine, triisopropanolamine, triisopropyl Piruamin and the like, aqueous solution compound other than this as long as it exhibits basicity can also be used.

  The concentration of the alkaline compound that can be suitably used in the development step of the photosensitive resin composition of the present invention is preferably 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight. Further, the temperature of the developer depends on the composition of the photosensitive resin composition and the composition of the developer, and is generally 0 ° C. or higher and 80 ° C. or lower, more generally 20 ° C. or higher and 50 ° C. or lower. It is preferable to use it.

  The pattern formed by the development step is rinsed to remove unnecessary developer residue. Examples of the rinsing liquid include water and acidic aqueous solutions.

  Next, a cured film rich in heat resistance and flexibility can be obtained by performing heat curing treatment. Although a cured film is determined in consideration of wiring thickness etc., it is preferable that thickness is about 2-50 micrometers. The final curing temperature at this time is desired to be cured by heating at a low temperature for the purpose of preventing oxidation of the wiring and the like and not reducing the adhesion between the wiring and the substrate. The heat curing temperature at this time is preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 200 ° C. or lower, and particularly preferably 130 ° C. or higher and 190 ° C. or lower. When the final heating temperature becomes high, the wiring may be oxidized and deteriorated.

  A pattern comprising a cured film formed from the photosensitive resin composition of the present invention is excellent in heat resistance, flame retardancy, electrical and mechanical properties, and is particularly excellent in flexibility. For example, the insulating film of the present invention preferably has a thickness of about 2 to 50 μm and a resolution of at least 10 μm after photocuring, and particularly a resolution of about 10 to 1000 μm. For this reason, the insulating film of the present invention is particularly suitable as an insulating material for a high-density flexible substrate. Furthermore, it is used for various photo-curing type wiring coating protective agents, photosensitive heat-resistant adhesives, electric wire / cable insulation coatings, and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[Synthesis Example 1: Synthesis of raw material phosphazene compound]
Into a 5 L flask equipped with a reflux condenser, thermometer, stirrer, phosphoric acid trichloride dropper and chlorine gas blowing tube, 2.5 L of chlorobenzene, 182.5 g (3.4 mol) of ammonium chloride and 2.5 g of zinc chloride were added. The mixed liquid separation was obtained. The dispersion was heated and dropped at a temperature of 130 ° C., and 425.5 g of phosphorus trichloride was added dropwise at a rate of 9 g / min over 48 minutes, and at the same time, 227 g of chlorine gas was supplied at a rate of 5 g / min over 46 minutes. After supplying phosphorus trichloride and chlorine gas, the reaction was completed by further refluxing (131 ° C.) for 150 minutes. Subsequently, unreacted ammonium chloride was removed by suction filtration, and chlorobenzene was removed at 30 to 50 ° C. under reduced pressure of 1.0 to 3.0 hPa to obtain 352 g of a reaction product. The yield of the reaction product based on phosphorus trichloride was 98.1%.

  The obtained reaction product was redissolved in chlorobenzene, and a mixture of hexachlorocyclotriphosphazene and octachlorocyclotetraphosphazene (226 g, hexachlorocyclotriphosphazene: 76%, octachlorocyclotetraphosphazene: 24%) was obtained by recrystallization. Obtained.

  The chlorobenzene solution remaining after recrystallization was concentrated to obtain 125 g of a cyclic and chain phosphazene compound of chlorophosphazene. In addition, 155 g of hexachlorocyclotriphosphazene having a purity of 99.9% was obtained by recrystallizing the mixture of hexachlorocyclotriphosphazene and octachlorocyclotetraphosphazene obtained previously three times using hexane.

[Synthesis Example 2: Synthesis of phenoxyphosphazene compound]
In a 2 L four-necked flask equipped with a reflux condenser, thermometer, stirrer, and dropping funnel, 58 g of hexachlorocyclotriphosphazene of 99.9% purity synthesized in Synthesis Example 1 (0.5 unit mol, 1 NPCl ₂₎ Unit) and 100 mL of THF was charged to obtain a solution. Next, while stirring separately prepared THF solution of 4-methoxyphenol Na salt (4-methoxyphenol 68.3 g (0.55 mol), sodium 11.1 g (0.44 g-atom), THF 200 mL), The solution was added dropwise to the THF solution of hexachlorocyclotriphosphazene over time. Since the reaction was intensely exothermic, the reaction was performed with appropriate cooling so that the reaction temperature did not exceed 30 ° C. After completion of the dropwise addition, the stirring reaction was continued at 60 ° C. for 6 hours. The residual chlorine content of the partially substituted product obtained by this reaction was 15.78%, and the estimated structure was N ₃ P ₃ Cl _3.36 (OC ₆ H ₄ OCH ₃ ) _2.63 .

  Next, a separately prepared THF solution of sodium phenolate (phenol 61.2 g (0.65 mol), sodium 13.8 g (0.6 g-atom), THF 200 mL) was cooled so that the reaction temperature was 30 ° C. or lower. Controlled and dripped over 1 hour. The reaction was then completed at room temperature for 5 hours and at reflux temperature for 3 hours to complete the reaction. After completion of the reaction, the solvent THF was distilled off under reduced pressure, and then 500 mL of toluene was added to redissolve the product. The organic layer was washed once with 5 wt% aqueous sodium hydroxide and once with 2 wt% aqueous sodium hydroxide, then washed once with (1 + 9) aqueous hydrochloric acid and once with 5 wt% aqueous sodium bicarbonate. Washed and then washed twice with water to make the aqueous layer neutral. Next, the organic layer was separated, dehydrated with anhydrous magnesium sulfate, and toluene was distilled off to obtain 122.6 g (yield 95%) of a pale yellow oily product. The amount of residual chlorine was 0.01% or less.

Cyclotriphosphazene 116.2 g (0.45 unit mol) in which 4-methoxyphenoxy group and phenoxy group obtained by the above method were mixed and 583.6 g (5.05 mol) of pyridine hydrochloride were mixed with 2 L of 4 ports. The flask was charged, the temperature was gradually raised, and the reaction was carried out at 205 to 210 ° C. for 1 hour. Subsequent operations were performed in the same manner as in Synthesis Example 2 to obtain 90.5 g (yield 81.8%) of a yellow solid. The residual chlorine content was 0.01% or less, and the hydroxyl group content was 6.1% (theoretical value 6.1%, composition formula N ₃ P ₃ (OPh) _3.36 (OC ₆ H ₄ OH) _2.63 , Hydroxyl equivalent weight 279).

[Synthesis Example 3: Synthesis of unsaturated double bond phosphazene compound having secondary hydroxyl group]
To a three-flask equipped with a reflux tube, 23.4 g of a phenoxyphosphazene compound having a hydroxyl group equivalent of 279 synthesized in Synthesis Example 2 (containing 84.0 mmol of hydroxyl group) and 40.0 g of tetrahydrofuran were completely dissolved. Further, 13.1 g (92.4 mmol) of glycidyl methacrylate and 0.4 g (4.2 mmol) of triethylamine were added under stirring in a nitrogen atmosphere, and the mixture was heated to 70 ° C. and stirred for 8 hours. The reaction solution was concentrated and then poured into hexane and decanted to separate the product (unreacted glycidyl methacrylate was removed by this operation). By vacuum drying overnight, 27.9 g of a phosphazene compound having an unsaturated double bond (methacryloyl group) (light brown highly viscous product) was obtained.

  As a result of measuring the 1H-NMR spectrum of the product, the integration of two signals (5.7 and 6.0 ppm) of the alkene derived from the methacryloyl group and the aromatic signal (6.6 to 7.2 ppm) derived from the phosphazene compound was obtained. From the comparison of values, it was confirmed that the reaction rate (introduction of methacryloyl group into the hydroxyl group of the phenoxyphosphazene compound) was about 50%.

[Synthesis Example 4: Synthesis of Reactive Flame Retardant 1]
40.0 g of tetrahydrofuran is completely dissolved in 27.9 g of an unsaturated double bond phosphazene compound having a secondary hydroxyl group synthesized in Synthesis Example 3 (containing 42 mmol of the secondary hydroxyl group) in a three-flask equipped with a reflux tube. I let you. Furthermore, 4.3 g (21 mmol) of norbornene diisocyanate and 0.1 g of dibutyltin dilaurate were added, and the mixture was heated to 80 ° C. and stirred for 6 hours in a nitrogen atmosphere. The reaction solution was concentrated and then poured into hexane, followed by decantation to separate the product (unreacted norbornene diisocyanate was removed by this operation). By vacuum drying overnight, 31.0 g of a reactive flame retardant (light brown high-viscosity) was obtained.

As a result of measuring the IR spectrum of the product, a signal (1680 cm ⁻¹ ) derived from a urethane carbonyl group was measured, and a urethane bond was confirmed.

[Synthesis Example 5: Synthesis of Reactive Flame Retardant 2]
40.0 g of tetrahydrofuran is completely dissolved in 27.9 g of an unsaturated double bond phosphazene compound having a secondary hydroxyl group synthesized in Synthesis Example 3 (containing 42 mmol of the secondary hydroxyl group) in a three-flask equipped with a reflux tube. I let you. Further, 4.3 g (42 mmol) of norbornene diisocyanate, 10.5 g (21 mmol) of polycarbonate diol (manufactured by Daicel Chemical Industries, Plaxel CD205PL, average molecular weight 500), and 0.1 g of dibutyltin dilaurate were added to 80 ° C. The mixture was heated and stirred for 6 hours under a nitrogen atmosphere. The reaction solution was concentrated and then poured into hexane, followed by decantation to separate the product (unreacted norbornene diisocyanate was removed by this operation). By vacuum drying overnight, 54.0 g of a reactive flame retardant (light brown highly viscous product) was obtained.

As a result of measuring the IR spectrum of the product, a signal (1680 cm ⁻¹ ) derived from a urethane carbonyl group was measured, and a urethane bond was confirmed.

(Examples 1-2) and (Reference Examples 1-2)
A photosensitive resin, a photopolymerization initiator, a thermosetting resin, and an organic solvent are added to the phosphazene compound obtained in Synthesis Examples 2-3 and the reactive flame retardant obtained in Synthesis Examples 4-5, and the photosensitive resin is added. A composition was prepared. Table 1 shows the blending amount of each constituent raw material in the resin solid content and the kind of the raw material. In addition, 1,2-bis (2-methoxyethoxy) ethane, which is a solvent in the table, is the total amount of solvent including the solvent and the like contained in the photosensitive resin composition solution.

  The photosensitive resin composition was first mixed with a typical stirring device with a stirring blade, and the solution was passed twice with a three-roll mill to obtain a uniform solution. When the particle diameter was measured with a grindometer, all were 10 μm or less. The following evaluation was carried out by completely defoaming the foam in the solution with a defoaming device. The evaluation results are shown in Table 2.

(Comparative Example 1)
Reactive flame retardant (MR-260 manufactured by Daihachi Chemical Industry Co., Ltd. (diphenyl- (2-methacryloyloxyethyl) phosphate)), photosensitive resin, photopolymerization initiator, thermosetting resin, and organic solvent are added for photosensitivity. A functional resin composition was prepared. Table 1 shows the blending amount of each constituent raw material in the resin solid content and the kind of the raw material. In addition, 1,2-bis (2-methoxyethoxy) ethane, which is a solvent in the table, is the total amount of solvent including the solvent and the like contained in the photosensitive resin composition solution.

  In the same manner as in Examples 1 and 2, the photosensitive resin composition was first mixed with a general stirring device with a stirring blade, and the solution was passed twice with a three-roll mill to obtain a uniform solution. When the particle diameter was measured with a grindometer, all were 10 μm or less. The following evaluation was carried out by completely defoaming the foam in the solution with a defoaming device. The evaluation results are shown in Table 2.

<1> Product name MR-260 (diphenyl- (2-methacryloyloxyethyl) phosphate) manufactured by Daihachi Chemical Industry Co., Ltd.
<2> Nippon Kayaku Co., Ltd. product name KayaradZFR1401H (acid-modified epoxy acrylate resin)
<3> Product name NK ester A-9300 (ethoxylated isocyanuric acid triacrylate) manufactured by Nakamura Chemical Co., Ltd.
<4> Product name NK ester BPE-1300 (bisphenol AEO modified diacrylate) manufactured by Nakamura Chemist
<5> Product name Irgacure 369 (2-benzyl-2-dimethylamino-4-morpholino notyrophenone) manufactured by Ciba Specialty Chemicals
<6> Nippon Kayaku Co., Ltd. product name RE-303S (bisphenol A type epoxy resin).

<Preparation of coating film on polyimide film>
The above photosensitive resin composition was cast and applied to an area of 100 mm × 100 mm on a 75 μm polyimide film (manufactured by Kaneka Corporation: trade name 75 NPI) using a Baker type applicator so that the final dry thickness was 25 μm. After drying at 80 ° C. for 20 minutes, a negative photomask with a line width / space width of 50 mm × 50 mm = 100 μm / 100 μm was placed and irradiated with ultraviolet rays with an integrated exposure amount of 300 mJ / cm ² to be exposed. Subsequently, spray development was performed for 60 seconds at a discharge pressure of 1.0 kgf / mm ² using a solution obtained by heating a 1.0 wt% sodium carbonate aqueous solution to 30 ° C. After development, the film was sufficiently washed with pure water, and then cured by heating in an oven at 150 ° C. for 60 minutes to prepare a cured film of the photosensitive resin composition.

<Evaluation of cured film>
The obtained cured film was evaluated for the following items. The evaluation results are shown in Table 2.

(I) Photosensitivity evaluation The photosensitivity evaluation of the photosensitive resin composition was determined by observing the surface of the cured film obtained in the above item <Preparation of coating film on polyimide film>.
◯: A clear photosensitive pattern with a line width / space width = 100/100 μm is drawn on the polyimide film surface, the line does not shake due to the peeling of the line portion, and there is no residual residue in the space portion. thing.
Δ: A clear line width / space width = 100/100 μm photosensitive pattern is drawn on the polyimide film surface, and the line portion is shaken due to peeling, but there is no undissolved residue in the space portion. thing.
×: A clear line width / space width = 100/100 μm photosensitive pattern was not drawn on the polyimide film surface, and the exposed portion was partially or entirely dissolved.

(Ii) Adhesiveness of cured film The adhesive strength of the cured film obtained in the above item <Preparation of coating film on polyimide film> was evaluated by a cross-cut tape method according to JIS K5400.
○: No peeling by cross-cut tape method Δ: 95% or more of the squares remain ×: The residual quantity of the squares is less than 80%.

(Iii) Solvent resistance The solvent resistance of the cured film obtained in the above item <Preparation of coating film on polyimide film> was evaluated. In the evaluation method, the film was dipped in methyl ethyl ketone at 25 ° C. for 15 minutes and then air-dried, and the state of the film surface was observed.
○: There is no abnormality in the coating film.
X: Abnormality such as swelling or peeling occurs in the coating film.

(Iv) Flexibility A cured film laminated film of a photosensitive resin composition on the surface of a polyimide film having a thickness of 25 μm (Apical 25NPI manufactured by Kaneka Corporation) in the same manner as in the above item <Preparation of coating film on polyimide film>. Was made. The cured film laminated film was cut into a 30 mm × 10 mm strip, bent at 180 ° 10 times at 180 °, and visually checked for cracks in the coating film.
○: The cured film has no cracks Δ: The cured film has some cracks x: The cured film has cracks

(V) Insulation reliability Line width / space width = 100 μm on flexible copper-clad laminate (copper foil thickness 12 μm, polyimide film is Apical 25 NPI manufactured by Kaneka Co., Ltd., and copper foil is bonded with polyimide adhesive) A / 100 μm comb-shaped pattern was prepared, immersed in a 10% by volume sulfuric acid aqueous solution for 1 minute, washed with pure water, and subjected to a copper foil surface treatment. Then, the cured film of the photosensitive resin composition was produced on the comb pattern by the method similar to the above-mentioned <Preparation of the coating film on a polyimide film> method, and the test piece was adjusted. A 100 V direct current was applied to both terminals of the test piece in an environmental test machine at 85 ° C. and 85% RH, and changes in the insulation resistance value and occurrence of migration were observed.
◯: A resistance value of 10 8 or more in 1000 hours after the start of the test and no occurrence of migration, dendrite, etc. ×: An occurrence of migration, dendrite, etc. in 1000 hours after the start of the test.

(Vi) Wettability The wettability of the cured film obtained in the above item <Preparation of coating film on polyimide film> was evaluated according to JIS K6768.

(Vii) Solder heat resistance A cured film of a photosensitive resin composition is laminated on the surface of a 75 μm-thick polyimide film (Apical 75NPI manufactured by Kaneka Corporation) in the same manner as in the above item <Preparation of coating film on polyimide film>. A film was prepared.

The coated film was floated so that the surface coated with the cured film of the photosensitive resin composition was in contact with a solder bath completely dissolved at 260 ° C., and then pulled up 10 seconds later. The operation was performed three times, and the adhesive strength of the cured film was evaluated by a cross-cut tape method according to JIS K5400.
○: No peeling by cross-cut tape method Δ: 95% or more of the squares remain ×: The residual quantity of the squares is less than 80%.

(Viii) Warpage A cured film laminated film of a photosensitive resin composition is applied to the surface of a 25 μm-thick polyimide film (Apical 25NPI manufactured by Kaneka Corporation) in the same manner as in the above item <Preparation of coating film on polyimide film>. Produced.

  The cured film was cut into a film having an area of 50 mm × 50 mm and placed on a smooth table so that the coating film was on the upper surface, and the warp height of the film edge was measured. A schematic diagram of the measurement site is shown in FIG. The smaller the amount of warpage on the polyimide film surface, the smaller the stress on the surface of the printed wiring board and the lower the amount of warping of the printed wiring board. The warp amount is preferably 5 mm or less.

(Ix) Flame retardancy In accordance with the flame retardancy test standard UL94 for plastic materials, a flame retardancy test was performed as follows. A cured film laminated film of a photosensitive resin composition is applied to one side of a polyimide film having a thickness of 12.5 μm (Apical 12.5AH manufactured by Kaneka Corporation) in the same manner as the above item <Preparation of coating film on polyimide film>. Produced. The prepared sample was cut into dimensions: 50 mm width × 200 mm length × 27.5 μm thickness (including the thickness of the polyimide film), a marked line was put in the 125 mm portion, and the diameter was about 13 mm so that the coated surface would be the outside of the roll. The PI tape was affixed so that there were no gaps in the overlapping portion (75 mm) above the marked line and the upper part, and 20 flame retardant test tubes were prepared. Of these, 10 were treated at (1) 23 ° C./50% relative humidity / 48 hours, and the remaining 10 were treated at (2) 70 ° C. for 168 hours and then cooled in a desiccator containing anhydrous calcium chloride for 4 hours or more. The upper part of these samples is clamped and fixed vertically, and a burner flame is brought close to the lower part of the sample for 10 seconds to ignite. After 10 seconds, remove the burner flame and measure how many seconds after the flame or burning of the sample has disappeared.
○: For each condition ((1), (2)), the flame and combustion stopped within 5 seconds on average (average of 10) after the flame of the burner was moved away from the sample, and self-extinguishment within 10 seconds at maximum X: One sample that does not extinguish within 10 seconds, or the flame rises to the clamp at the top of the sample and burns.

(X) Bleed-out The test piece after the above insulation reliability test was observed to observe a minute bulge on the surface of the test piece, a bulge on the copper wiring, a seepage of oily substances, and the like.
○: Swelled on the surface of the test piece and the copper wiring in 1000 hours after starting the test, and no abnormality such as oozing out was observed. ×: Swelled and oozed out on the surface of the test piece and the copper wiring in 1000 hours after starting the test. Any abnormalities such as

DESCRIPTION OF SYMBOLS 1 Polyimide film which laminated the photosensitive resin composition 2 Warpage amount 3 Smooth stand

Claims (9)

  A reactive flame retardant comprising (a) a phosphazene structure, (b) a photosensitive group, and (c) a urethane bond in a molecule.   The reactive flame retardant according to claim 1, wherein the photosensitive group (b) is selected from at least one of a vinyl group, an acryloyl group, and a methacryloyl group. The reactive flame retardant is represented by the following general formula (1)

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₃ represent a divalent organic group, R ₂ represents a phenyl group or a hydroxyphenyl group, and R ₄ represents a monovalent organic group.)
And a cyclic phenoxyphosphazene having a secondary hydroxyl group represented by the following general formula (2)

(In the formula, n represents an integer of 3 to 25, R ₆ and R ₈ represent a divalent organic group, R ₇ represents a phenyl group or a hydroxyphenyl group, and R ₉ represents a monovalent organic group.)
At least one hydroxyl group of the chain phenoxyphosphazene compound having a secondary hydroxyl group represented by the following general formula (3):

(In the formula, R ₅ represents a divalent organic group.)
The reactive flame retardant according to claim 1, which is obtained by reacting a diisocyanate compound represented by the formula: The cyclic phenoxyphosphazene compound having a secondary hydroxyl group and / or the chain phenoxyphosphazene compound having a secondary hydroxyl group is represented by the following general formula (4).

(In the formula, m represents an integer of 3 to 25, R ₁ and R ₂ represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
A cyclic phenoxyphosphazene compound represented by the following general formula (5):

(In the formula, n represents an integer of 3 to 25, R ₆ and R 7 represent a phenyl group or a hydroxyphenyl group, and one molecule contains at least one hydroxyphenyl group.)
And the phenolic hydroxyl group of the chain phenoxyphosphazene compound represented by the following general formula (6)

(In the formula, R ₁₀ represents a divalent organic group, and R ₄ represents a monovalent organic group.)
The reactive flame retardant according to claim 3, which is obtained by a reaction with an epoxy compound having an unsaturated double bond represented by:   A photosensitive resin composition comprising at least the reactive flame retardant according to any one of claims 1 to 4, (A) a photosensitive resin, and (B) a photopolymerization initiator.   A photosensitive resin composition solution obtained by dissolving the photosensitive resin composition according to claim 5 in an organic solvent.   The resin film obtained by apply | coating the photosensitive resin composition solution of Claim 6 to the base-material surface, and drying.   A cured film obtained by curing the resin film according to claim 7.   The printed wiring board with a cured film which coat | covered the cured film of Claim 8 on the printed wiring board.

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