JP2012098470A - Novel photosensitive resin composition and utilization of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in storage stability without decrease in the photosensitivity after long-term storage, excellent in microprocessing properties, developability, low-temperature curability, electric insulation reliability of a cured film, heat resistance against soldering, resistance against organic solvents, flame retardancy and the like.SOLUTION: The photosensitive resin composition comprises at least: an agent (A) containing (a1) a compound having a carboxyl group and no photosensitive group; and an agent (B) containing (b1) an epoxy resin and (b2) an oxime ester photopolymerization initiator. The (b1) epoxy resin is present in a solid state in the agent (B) at room temperature (25°C).

Description

  The present invention relates to a photosensitive resin composition, a resin film obtained therefrom, an insulating film, and a printed wiring board with an insulating film.

  Conventionally, in the printed wiring board manufacturing industry, a coverlay film obtained by applying an adhesive to a molded body such as a polyimide film has been used as a surface protective material for a flexible circuit board. When bonding this coverlay film on a flexible circuit board, there is a method in which an opening is provided in advance by a method such as punching in a terminal portion of a circuit or a joint portion with a component, and after aligning, a method of thermocompression bonding by a hot press or the like is used. It is common. Further, the cover lay film is required to have excellent characteristics such as heat resistance, chemical resistance, flame retardancy, adhesion, and electrical insulation reliability. Regarding flame retardancy, good flame retardancy can be obtained by using a halogen-based flame retardant, but from the viewpoint of environmental impact, a flame-retarding technique that does not contain a halogen-based flame retardant is required.

  The cover lay film having the above configuration is difficult to provide a high-precision opening, and the positioning at the time of pasting is often performed manually, so that the positional accuracy is poor and the pasting workability is also poor. Therefore, a solder resist having a photosensitive function may be used, and it is excellent in fine workability. As this photosensitive solder resist, a photosensitive resin composition mainly composed of an epoxy resin or the like is used. This photosensitive solder resist is excellent in electrical insulation reliability as an insulating material, but has mechanical properties such as flexibility. However, since the curing shrinkage is large, when it is laminated on a thin and flexible circuit board such as a flexible circuit board, the warpage of the board becomes large and it is difficult to use it for a flexible circuit board. Further, the flame retardancy is poor, and when a flame retardant is added for the purpose of imparting flame retardancy, there are problems such as deterioration in physical properties and contact failure due to bleeding out from the cured film and process contamination.

  In recent years, various proposals have been made that can exhibit flame retardancy as the photosensitive solder resist.

  For example, Patent Document 1 proposes a flame-retardant photocurable resin composition containing a phosphazene compound, a carboxyl group-containing resin, and a photopolymerization initiator that are liquid at room temperature. Patent Document 2 proposes a flame retardant photocurable resin composition containing a carboxyl group-containing resin, a soluble phosphazene compound that is soluble in a carboxyl group-containing resin by 5 wt% or more, and a photopolymerization initiator.

JP 2010-39389 A JP 2010-113245 A

  In the above patent document, various methods for solving the problem of the coverlay are proposed. However, the resin compositions described in Patent Documents 1 and 2 can form a coverlay that has a non-halogen composition and has a low environmental load and excellent flame retardancy, but the epoxy resin is dissolved in the curing agent. It may affect the decomposition of the photopolymerization initiator, and further causes a decrease in tackiness of the resulting coating film. Moreover, the viewpoint in the long-term storage stability of the photosensitivity which is the effect of this invention is not described, and the essence is different from the invention of this application.

  As a result of diligent research to solve the above problems, the present inventors have at least (a1) an agent A containing a compound having a carboxyl group and a photosensitive group, (b1) an epoxy resin, and (b2) an oxime ester-based light. A photosensitive resin composition comprising a B agent containing a polymerization initiator, wherein the (b1) epoxy resin is present in a solid at room temperature (25 ° C.) in the B agent. The photosensitive resin composition characterized by the above can be finely processed because it has photosensitivity, can be developed with a dilute alkaline aqueous solution, can be cured at a low temperature (200 ° C. or less), and is photosensitive after long-term storage. Based on these findings, we have obtained knowledge that there is no deterioration and excellent storage stability, and that a cured resin film can be obtained with a photosensitive resin composition excellent in electrical insulation reliability, solder heat resistance, organic solvent resistance, and flame resistance. In the present invention One in which the.

  The present invention can solve the above problems by the following novel photosensitive resin composition.

  That is, the present invention comprises at least (a1) an agent A containing a compound having a carboxyl group and a photosensitive group, and (b1) an epoxy resin and (b2) an agent B containing an oxime ester photopolymerization initiator. A photosensitive resin composition characterized in that the (b1) epoxy resin is present in solid form at room temperature (25 ° C.) in the agent B. is there.

  Moreover, it is preferable that the photosensitive resin composition concerning this invention contains the compound which does not have a carboxyl group in (A1) agent and / or B agent, and has a photosensitive group.

  The compound (a1) having a carboxyl group and a photosensitive group may be a compound having at least one carboxyl group and a photosensitive group selected from the group consisting of epoxy acrylate, urethane acrylate and acrylated acrylate. preferable.

  Moreover, the resin film concerning this invention is obtained by drying, after apply | coating the said photosensitive resin composition to the base-material surface.

  The insulating film according to the present invention is obtained by curing the resin film.

  The printed wiring board with an insulating film according to the present invention is obtained by covering the printed wiring board with the insulating film.

  Since the photosensitive resin composition of the present invention has photosensitivity, it can be finely processed, can be developed with a dilute alkali aqueous solution, can be cured at a low temperature (200 ° C. or less), and has a reduced photosensitivity after long-term storage. No storage stability. Further, the cured film obtained from the photosensitive resin composition is excellent in electrical insulation reliability, solder heat resistance, organic solvent resistance and flame retardancy, and has good physical properties. Therefore, the photosensitive resin composition of the present invention can be used for protective films of various circuit boards and exhibits excellent effects.

  Hereinafter, the present invention will be described in detail in the order of (I) the photosensitive resin composition and (II) the method of using the photosensitive resin composition.

(I) Photosensitive resin composition The photosensitive resin composition of the present invention comprises at least (a1) an agent A containing a compound having a carboxyl group and a photosensitive group, (b1) an epoxy resin, and (b2) an oxime ester. A photosensitive resin composition comprising a B agent containing a photopolymerization initiator, wherein the (b1) epoxy resin is present in solid form at room temperature (25 ° C.) in the B agent do it.

Here, since the productivity is generally excellent, the photopolymerization initiator is often used as a component of the agent A. However, when the (b2) oxime ester-based photopolymerization initiator used in the present invention is used as the composition of the agent A, the storage stability is greatly reduced, so that it cannot be used in a general composition. Surprisingly, however, the photosensitive resin composition of the present invention has high storage stability and excellent properties in spite of the use of the (b2) oxime ester photopolymerization initiator. They found out. This is presumed to be due to the following reasons. In other words,
The photosensitive resin composition of the present invention contains at least (a1) a compound having a carboxyl group and a photosensitive group. By having a carboxyl group, it becomes soluble in a developer typified by a dilute alkaline aqueous solution, and fine processing becomes possible by exposure and development. In addition, (a1) A agent containing a compound having a carboxyl group and a photosensitive group and (b1) an epoxy resin, (b2) B agent containing an oxime ester photopolymerization initiator are used for long-term storage. There is no subsequent photosensitivity reduction and excellent storage stability. The reason why the storage stability of the photosensitivity is excellent is that when a compound having a carboxyl group and an epoxy resin coexist, the reaction between the carboxyl group and the epoxy group gradually proceeds at room temperature (25 ° C.). When a compound having a group and an oxime ester photopolymerization initiator coexist, an acidic atmosphere in which a carboxyl group exists acts as a catalyst, hydrolysis of the oxime ester occurs, and, further, an epoxy resin is used at room temperature (25 ° C. ), When it does not exist as a solid, the decomposition reaction of the oxime ester photopolymerization initiator is likely to occur due to the interaction with the oxime ester photopolymerization initiator mixed in the B agent, and a plurality of factors causing a decrease in stability. Is presumed to be due to the elimination of

  Hereinafter, the present invention will be described in detail with respect to the photosensitive resin composition. (Meth) acrylic acid in the present invention means acrylic acid and / or methacrylic acid, and (meth) acrylate has the same meaning.

<(A1) Compound having carboxyl group and photosensitive group>
The compound having (a1) carboxyl group and photosensitive group in the present invention is not particularly limited as long as it is a compound having at least one carboxyl group and photosensitive group. In particular, epoxy acrylate, urethane acrylate, and acrylated acrylate are preferable because of excellent balance of various properties of the cured film. The epoxy acrylate is a compound obtained by adding a saturated or unsaturated polyvalent carboxylic acid anhydride to an ester obtained by reacting an epoxy compound with an unsaturated monocarboxylic acid. Examples of the saturated or unsaturated polycarboxylic acid anhydride include anhydrides such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, and trimellitic acid. The urethane acrylate is a diol compound having a carboxyl group, a diisocyanate compound, a diol compound having an ethylenically unsaturated group and / or an isocyanate compound having an ethylenically unsaturated group and / or ethylenic. It is a compound obtained by reacting an epoxy compound having an unsaturated group. The above acrylated acrylate is obtained by obtaining a copolymer with (meth) acrylic acid and (meth) acrylic ester having a carboxyl group and a copolymerizable double bond, and glycidyl methacrylate with a part of the side chain carboxyl group. It is a compound obtained by reacting with an epoxy group of a compound having a (meth) acryl group and an epoxy group.

  Examples of such epoxy acrylates include ZFR series, ZAR series, ZCR series, CCR series, and PCR series manufactured by Nippon Kayaku Co., Ltd., and urethane acrylates include, for example, UXE series manufactured by Nippon Kayaku Co., Ltd. Examples of the acrylated acrylate include Cyclomer ACA series manufactured by Daicel Cytec.

<(B1) Epoxy resin>
The (b1) epoxy resin used in the present invention is classified as the B agent separately from the A agent containing the compound (a1) having a carboxyl group and a photosensitive group. By setting it as the said structure, the photosensitive resin composition which does not have the photosensitivity fall after long-term storage, and is excellent in storage stability is obtained. The (b1) epoxy resin is a compound containing at least one epoxy group in the molecule, and further exists in the agent B as a solid at room temperature (25 ° C.). (B1) When the epoxy resin is present in the B agent as a solid at room temperature (25 ° C.), the deterioration of the (b2) oxime ester photopolymerization initiator mixed in the B agent is small, and after long-term storage, The photosensitive resin composition is not deteriorated in photosensitivity and is excellent in storage stability. Furthermore, there is an effect that the coating film after drying is excellent in tackiness. The above-mentioned (b1) epoxy resin is preferable because it is crystalline and easily exists as a solid at room temperature (25 ° C.) in the agent B. For example, trade names jERYX4000, jERYX4000K, jERYX4000H manufactured by Japan Epoxy Resins Co., Ltd. , JERYX4000HK, jERYX8800, trade names TEPIC-G, TEPIC-P, TEPIC-S, TEPIC-SP manufactured by Nissan Chemical Industries, Ltd., GTR-1800 manufactured by Nippon Kayaku Co., Ltd., and the like.

  Here, (b1) that the epoxy resin exists as a solid in the B agent at room temperature (25 ° C.) means that the epoxy resin that is solid at room temperature (25 ° C.) is completely dissolved in the B agent. It means that the whole or part of the epoxy resin is present as a solid. The presence of the epoxy resin as a solid in the B agent at room temperature (25 ° C.) means that, for example, the particle diameter is measured by a method using a gauge specified in JIS K 5600-2-5, and the presence or absence of particles Can be confirmed. Moreover, it can also confirm by isolate | separating solid content by filtration etc. and performing qualitative analysis with various analysis methods.

<(B2) Oxime ester photopolymerization initiator>
The (b2) oxime ester photopolymerization initiator in the present invention is a compound having an oxime ester structure, activated by energy such as UV, and initiating / promoting a reaction of a radical polymerizable group. The (b2) oxime ester photopolymerization initiator needs to be separated from the (a1) agent A containing a compound having a carboxyl group and a photosensitive group. Although it will not specifically limit if it is divided with A agent, Since it is excellent in productivity and operativity, it is preferable to set it as the composition of B agent similarly to the said (b1) epoxy resin. By setting it as the said structure, the photosensitive resin composition which does not have the photosensitivity fall after long-term storage, and is excellent in storage stability is obtained. Examples of the (b2) oxime ester photopolymerization initiator include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9. -Ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxyome) and the like.

<(C1) Compound having no carboxyl group and having a photosensitive group>
The compound (c1) having no carboxyl group and having a photosensitive group in the present invention contains a radically polymerizable group that has substantially no carboxyl group and undergoes a polymerization reaction by a radical polymerization initiator in the molecule. Any of the above-mentioned A agent and B agent compositions may be used. Among these, a resin having at least one unsaturated double bond in the molecule is preferable. Furthermore, the unsaturated double bond is preferably a (meth) acryloyl group or a vinyl group.

  Examples of the compound (c1) having no carboxyl group and having a photosensitive group 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 = 2-50) 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-hexanediol diacrylate, neopentyl glycol diacrylate, ethylene glycol diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol Hexaacrylate, tetramethylolpropane tetraacrylate, tetraethylene glycol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, ethylene glycol dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol Trimethacrylate, dipentaerythritol hexamethacrylate, tetramethylolpropane tetramethacrylate, tetraethylene glycol dimethacrylate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, β-methacryloyloxyethyl hydrogen phthalate, β-methacryloyloxyethyl hydrogen Succinate, 3-chloro-2-hydroxypropyl methacrylate, stearyl methacrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxypolyethylene 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-dimethacrylate Roxypropane, 2, 2 -Bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane, polyethylene glycol Diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2-bis [4- (acryloxy-diethoxy) phenyl] propane, 2,2-bis [4- (acryloxy-polyethoxy) phenyl] propane, 2- Hydroxy-1-acryloxy-3-methacryloxypropane, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, methoxydipropylene glycol Chryrate, methoxytriethylene glycol acrylate, nonylphenoxypolyethylene glycol acrylate, nonylphenoxy polypropylene glycol acrylate, 1-acryloyloxypropyl-2-phthalate, isostearyl acrylate, polyoxyethylene alkyl ether acrylate, nonylphenoxyethylene glycol acrylate, polypropylene glycol di Methacrylate, 1,4-butanediol dimethacrylate, 3-methyl-1,5-pentanediol dimethacrylate, 1,6-mexanediol dimethacrylate, 1,9-nonanediol methacrylate, 2,4-diethyl-1, 5-pentanediol dimethacrylate, 1,4-cyclohexanedimethanol dimethacrylate, di Propylene glycol diacrylate, tricyclodecane dimethanol diacrylate, 2,2-hydrogenated bis [4- (acryloxypolyethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolypropoxy) 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, propoxylated pentathritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol polyacrylate, triallyl isocyanurate, glycerin Sidyl methacrylate, glycidyl allyl ether, 1,3,5-triacryloylhexahydro-s-triazine, triallyl 1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, triallyl phosphate, alloverbital, 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′-isopropylidene diphenol diacrylate, etc. are preferred, but not limited thereto. In particular, the repeating unit of EO (ethylene oxide) contained in one molecule of diacrylate or dimethacrylate 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 increase the photosensitivity by using the EO-modified diacrylate or dimethacrylate together with a compound having three or more acryloyl groups or methacryloyl groups. For example, ethoxylated isocyanuric acid EO-modified triacrylate, ethoxy Isocyanuric acid EO-modified trimethacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate Ethoxylated pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrime Rollpropane tetraacrylate, 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 (1)

(Where a + b = 6 and n = 12.)
A compound represented by the following general formula (2)

(Where a + b = 4 and n = 4)
A compound represented by the following formula (3)

A compound represented by the following general formula (4)

(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 (5)

(Where a + b + c = 3.6)
A compound represented by the following formula (6)

A compound represented by the following general formula (7)

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

  The compound (c1) having no carboxyl group and having a photosensitive group in the photosensitive resin composition of the present invention is blended so as to be 10 to 200 parts by weight per 100 parts by weight of the component (a1). Is preferable in terms of improving the photosensitivity of the photosensitive resin composition.

  When the amount of the component (c1) is less than the above range, the alkali resistance of the cured film after photocuring the photosensitive resin composition may be lowered, and contrast may not be easily obtained when exposed and developed. In addition, when the component (c1) is larger than the above range, the coating film obtained by applying the photosensitive resin composition on the substrate and drying the solvent becomes more sticky, resulting in a decrease in productivity. Moreover, when the crosslinking density becomes too high, the cured film may be brittle and easily cracked. For this reason, it is possible to set the resolution at the time of exposure / development to an optimal range by setting the value within the above range.

<Other ingredients>
Various additives such as a flame retardant, a filler, an adhesion assistant, an antifoaming agent, a leveling agent, a colorant, and a polymerization inhibitor can be added to the photosensitive resin composition of the present invention as necessary. As said flame retardant, a phosphate ester type compound, a halogen-containing compound, a metal hydroxide, an organic phosphorus type compound, etc. can be contained, for example. The above various additives can be used alone or in combination of two or more. Moreover, it is desirable to select each content suitably. Further, as the filler, a fine inorganic filler such as silica, mica, talc, barium sulfate, wollastonite, calcium carbonate, or a fine organic polymer filler may be contained. Moreover, as said antifoamer, a silicon type compound, an acryl-type compound, etc. can be contained, for example. Moreover, as said leveling agent, a silicon type compound, an acryl-type compound, etc. can be contained, for example. Moreover, as said coloring agent, a phthalocyanine type compound, an azo type compound, carbon black, a titanium oxide etc. can be contained, for example. Moreover, as said adhesion assistant (it is also called adhesiveness imparting agent), a silane coupling agent, a triazole type compound, a tetrazole type compound, a triazine type compound, etc. can be contained. Moreover, as said polymerization inhibitor, hydroquinone, hydroquinone monomethyl ether, etc. can be contained, for example.

(II) Method of using photosensitive resin composition The photosensitive resin composition of the present invention is composed of at least two agents, A agent and B agent. A cured film or a relief pattern can be formed as follows using the mixture obtained by mixing two agents directly or after preparing a mixture solution. First, the photosensitive resin composition or the photosensitive resin composition solution is applied to a substrate and dried to remove the organic solvent. Application to the substrate can be performed by screen printing, curtain roll, reverse roll, spray coating, spin coating using a spinner, or the like. The coating film (preferably thickness: 5 to 100 μm, particularly preferably 10 to 100 μm) is dried at 120 ° C. or less, preferably 40 to 100 ° C.

  Next, 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. Next, the relief 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 spraying pressure and flow rate of the developing device and the temperature of the etching solution, it is desirable 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, and 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, triiso Etc. can be mentioned Ropiruamin, aqueous solution with compounds of other long as it exhibits basicity can also be naturally 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 20% by weight, particularly preferably 0.02 to 10% by weight. Further, the temperature of the developer depends on the composition of the photosensitive resin composition and the composition of the alkali developer, and is generally 0 ° C. or higher and 80 ° C. or lower, more generally 10 ° C. or higher and 60 ° C. or lower. Is preferably used.

  The relief pattern formed by the development process is rinsed to remove unnecessary residues. Examples of the rinsing liquid include water and acidic aqueous solutions.

  Next, heat treatment of the relief pattern obtained above is performed. By carrying out heat treatment to react the reactive groups remaining in the molecular structure, a cured film having high heat resistance can be obtained. The thickness of the cured film is determined in consideration of the wiring thickness and the like, but is preferably about 2 to 50 μm. The final curing temperature at this time is desired to be able 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 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 180 ° C. or lower. If the final heating temperature is high, the wiring is oxidatively deteriorated, which is not desirable.

  The cured film formed from the photosensitive resin composition of the present invention is excellent in flame retardancy, heat resistance, chemical resistance, electrical and mechanical properties.

  In addition, for example, the insulating film obtained from the photosensitive resin composition preferably has a thickness of about 2 to 50 μm and a resolution of at least 10 μm after photocuring, particularly a resolution of about 10 to 1000 μm. For this reason, the insulating film obtained from the photosensitive resin composition is particularly suitable as an insulating material for a high-density flexible substrate. Furthermore, it is used for various photo-curing wiring coating protective agents, photosensitive heat-resistant adhesives, electric wire / cable insulation coatings, and the like.

  In addition, this invention can provide the same insulating material even if it uses the resin film obtained by apply | coating the said photosensitive resin composition or the photosensitive resin composition solution to the base-material surface, and drying.

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

(Examples 1-3)
(A1) a compound having a carboxyl group and a photosensitive group, (b1) an epoxy resin, (b2) an oxime ester-based photopolymerization initiator, (c1) a compound having no carboxyl group and having a photosensitive group, other components, In addition, 1,2-bis (2-methoxyethoxy) ethane, which is an organic solvent, was added to prepare a photosensitive resin composition composed of agent A and agent B. Table 1 shows the blending amount of each constituent raw material in the resin solid content and the kind of the raw material. At this time, each of the A agent and the B agent was mixed and dispersed by performing two passes with three rolls. The obtained B agent was confirmed according to the method described in JIS K 5600-2-5, using a Yasuda Seiki Seisakusho grindometer with a groove depth of 0 μm to 50 μm. It was confirmed that it was present as a solid in the agent. The mixing ratio of the A agent and the B agent is a ratio as shown in the table. For example, in Example 1, 90.0 g of the A agent and 21.0 g of the B agent were mixed in terms of solid content.

<1> Product name of carboxyl group-containing epoxy acrylate manufactured by Nippon Kayaku Co., Ltd. Solid content 65%
<2> Product name of carboxyl group-containing urethane acrylate manufactured by Nippon Kayaku Co., Ltd. Solid content 65%
<3> Product name of powder epoxy resin manufactured by Japan Epoxy Resin Co., Ltd. <4> Product name of oxime ester photopolymerization initiator manufactured by BASF Japan <5> Product of phosphazene compound (phosphorous flame retardant) manufactured by Otsuka Chemical Co., Ltd. Name <6> Product name of Nippon Kayaku Co., Ltd. crystalline epoxy resin <7> Product name of Hitachi Chemical Co., Ltd. bisphenol A dimethacrylate <8> Product name of Japan Epoxy Resin liquid epoxy resin

<Preparation of coating film on polyimide film>
The photosensitive resin composition consisting of the above-mentioned agent A and agent B is mixed, and using a baker type applicator, 100 mm so that the final dry thickness is 20 μm on a 25 μm polyimide film (manufactured by Kaneka Corporation: trade name 25 NPI). The film was cast and applied to an area of × 100 mm and dried at 80 ° C. for 20 minutes. After placing a negative photomask as required, exposure was performed by irradiating with an ultraviolet ray having an accumulated exposure amount of 300 mJ / cm ² . Next, 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 thoroughly 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 on the polyimide film.

<Evaluation>
A coating film was prepared by the above method using the photosensitive resin composition, and the following items were evaluated. The evaluation results are shown in Table 2.

(I) Photosensitive Storage Stability Photosensitive resin having a thickness of 20 μm 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>. A cured film laminated film of the composition was prepared. During the exposure, a 21-step tablet photomask (T2115 manufactured by Stouffer) was used. The step tablet step number of the cured film was used as a reference value.
Furthermore, the A agent and B agent before mixing were stored at 40 ° C., and the same evaluation was performed after each elapsed day. Thereafter, a determination was made based on the following criteria.
○: After 300 days, the number of steps of the step tablet is in the range of ± 1 with respect to the reference value.
Δ: After 50 days, the number of steps of the step tablet is in the range of ± 1 with respect to the reference value.
×: After 50 days, the step tablet plate number is not in the range of ± 1 with respect to the reference value.

(Ii) Flame retardancy In accordance with the UL94VTM method of plastic material flammability test, the flammability test was conducted as follows. A cured film of photosensitive resin composition having a thickness of 20 μm on both sides of a polyimide film having a thickness of 25 μm (manufactured by Kaneka Corporation: trade name Apical 12.5 NPI) in the same manner as the above item <Preparation of coating film on polyimide film> A laminated film was produced. Cut out the sample prepared above into dimensions: 50 mm width x 200 mm length x 75 μm thickness (including the thickness of the polyimide film), put a marked line in the 125 mm part, round it into a cylinder with a diameter of about 13 mm, and above the marked line PI tape was affixed so that there was no gap in the overlapping part (75 mm location) 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 3 seconds to ignite. After 3 seconds, move the burner flame away and measure how many seconds after the sample flame or burning disappears.
○: For each condition ((1), (2)), the flame and combustion stopped within 10 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 However, it has not burned to the rating line.
×: Even one sample does not extinguish within 10 seconds, or the flame rises above the rating line and burns.

(Iii) Tackiness 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 the above item <Preparation of a coating film on a polyimide film> and dried. A coating film having a thickness of 20 μm after drying was obtained. The obtained film surface was bent and lightly overlapped, and a determination was made based on the following criteria.
○: The surfaces do not stick to each other.
X: The surfaces stick to each other.

(Iv) Solder heat resistance By a method similar to the above item <Preparation of coating film on polyimide film>, the surface of a 75 μm-thick polyimide film (Apical 75NPI manufactured by Kaneka Corporation) has a 20 μm-thick photosensitive resin composition. A cured film laminated film was produced.
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 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.

(V) 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.

(Vi) Electrical insulation reliability Line width / space width on a flexible copper-laminated laminate (thickness of electrolytic copper foil 12 μm, polyimide film is Apical 25 NPI manufactured by Kaneka Co., Ltd., copper foil is bonded with polyimide adhesive) = 100 μm / 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. Thereafter, a cured film of a photosensitive resin composition having a thickness of 20 μm was prepared on the comb pattern by the same method as the above <Preparation of coating film on polyimide film>, 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 or dendrite.
X: Migration, dendrite, etc. occurred in 1000 hours after the start of the test.

(Comparative Examples 1-3)
As in the examples, a photosensitive resin composition composed of agent A and agent B 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. As in the Examples, the particle size was confirmed, and it was confirmed that only the component (b1) in Comparative Example 1 was present in the B agent as a solid. Evaluation was performed in the same manner as in the Examples using the obtained photosensitive resin composition. The evaluation results are shown in Table 2.

(Comparative Example 4)
As the agent A, 30 g of a liquid phenoxyphosphazene derivative (FP-390 manufactured by Fushimi Pharmaceutical Co., Ltd.), 150 g of a carboxyl group-containing resin (P7M50, solid content 50% manufactured by Kyoeisha), a carboxyl group-containing resin (ZCR manufactured by Nippon Kayaku Co., Ltd.) -1601H solid content 65%) 38 g, dipentaerythritol lactone-modified hexaacrylate (DPCA60, Nippon Kayaku Co., Ltd.) 20 g, phosphorus-containing compound-modified acrylate (Showa Polymer Co., Ltd. HFA-6065E) 23 g, melamine 5 g, silica (Admatechs Co., Ltd. Admafine SO-E2) 40 g, dipropylene glycol monomethyl ether 5 g, silicone-based antifoaming agent 3 g, pigment 1.1 g, B agent, photopolymerization initiator (Ciba Japan IRUGACURE907) 10 g , Photopolymerization open Agent (CGI-325 manufactured by Ciba Japan Co., Ltd.), 0.5 g of photopolymerization initiator (IRUGACURE OXE02 manufactured by Ciba Japan Co., Ltd.), biphenol novolac type epoxy resin (NC-3000H manufactured by Nippon Kayaku Co., Ltd. 70% solid content) The photosensitive resin composition which mix | blended 60g and consists of A agent and B agent was produced. Similar to the Examples, the particle size was confirmed, and it was confirmed that the biphenol novolac type epoxy resin as the component (b1) was not present in the B agent as a solid. Evaluation was performed in the same manner as in the Examples using the photosensitive resin composition obtained by mixing 315.1 g of Agent A and 71 g of Agent B. The evaluation results are shown in Table 2.

Claims (6)

  It comprises at least (A1) an agent A containing a compound having a carboxyl group and a photosensitive group, and (b1) an epoxy resin and (b2) an agent B containing an oxime ester photopolymerization initiator. A photosensitive resin composition, wherein the (b1) epoxy resin is present as a solid in a B agent at room temperature (25 ° C.).   The photosensitive resin composition according to claim 1, further comprising (c1) a compound having a photosensitive group and having no carboxyl group in the agent A and / or the agent B.   The (a1) compound having a carboxyl group and a photosensitive group is a compound having at least one carboxyl group and a photosensitive group selected from the group consisting of epoxy acrylate, urethane acrylate and acrylated acrylate. The photosensitive resin composition according to claim 1 or 2.   The resin film obtained by apply | coating the photosensitive resin composition of any one of Claims 1-3 to the base-material surface, and drying.   An insulating film obtained by curing the resin film according to claim 4.   The printed wiring board with an insulating film which coat | covered the insulating film of Claim 5 on the printed wiring board.