JP2012015367A - Flexible printed board with integrated reinforcing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible printed board with an integrated reinforcing plate in which defects such as swelling do not occur even if a reinforcing plate is stuck onto a photosensitive resin composition.SOLUTION: The flexible printed board with an integrated reinforcing plate comprises: (A) a reinforcing plate; (B) a photosensitive resin composition; and (C) a flexible printed board constituted in this order. The photosensitive resin composition (B) contains a reactive surface conditioner (D).

Description

  The present invention relates to a flexible printed board integrated with a reinforcing plate, wherein even if a reinforcing plate is attached on a photosensitive resin composition, defects such as swelling do not occur during reflow mounting.

  In general, various printed circuit board protection means have been used in the production of printed wiring boards. For example, a resist is used in the etching process, and a solder resist is used in the soldering process. Also, in manufacturing a film-like printed wiring board (hereinafter abbreviated as a flexible printed circuit board) to be mounted on a small device or the like, wiring unrelated to the process is protected in a soldering process for mounting components. For this purpose, a solder resist is used. In such substrate protection means such as resist or solder resist, specifically, a cover lay in which a polyimide film is punched into a predetermined mold and laminated on a flexible printed circuit board, or an ink composed of a heat resistant material A cover coat for printing on a flexible printed circuit board has been used. Since the coverlay and covercoat also serve as a protective film for wiring after soldering, in addition to the flame resistance specified in the UL standard, there are bleed-out resistance, flexibility, adhesion, and cracks caused by bending during board assembly. No folding resistance and flexibility, heat resistance during soldering, moisture resistance, and insulation are required.

  A coverlay formed on a flexible printed circuit board by punching a polyimide film satisfies these required characteristics and is currently most widely used, but it requires an expensive mold for punching and is stamped. Since the film is manually aligned and bonded, there are problems in that the manufacturing cost of the substrate is high and it is difficult to form a fine pattern.

  On the other hand, since the cover coat requires a drying process for screen printing, there is a problem that the manufacturing cost of the substrate becomes high and the workability is poor.

  As a method for solving these problems, there has been proposed a method in which a photosensitive resin composition is applied in a liquid form or attached in a film form on a substrate. According to this method, since a film of the photosensitive resin composition is formed on a substrate and then a fine pattern can be easily formed by exposure, development, and heating by photographic technology. Various photosensitive resin compositions have been developed.

  For example, in a molecule that is halogen-free and has a high level of flame retardancy, has low warpage after curing, and can form a film with excellent plasticity, resolution, solder heat resistance, chemical resistance, etc. Resin component having acryloyl group and carboxyl group, soluble in dilute alkali solution, epoxy compound having two or more epoxy groups in one molecule, photopolymerization initiator, organophosphorus compound, diluent And an alkali development type photosensitive thermosetting resin composition (Patent Document 1) containing a polyimide resin having a predetermined structure, sufficiently satisfying flexibility, flame retardancy and heat press resistance A polymer having a carboxyl group with sufficiently excellent properties, a photopolymerizable compound having an ethylenically unsaturated bond and containing no halogen atom, a photopolymerization initiator, a phenoxyphosphazene compound, a phosphate ester Compound, and a photosensitive thermosetting resin composition containing a halogen-based flame retardant (Patent Document 2) are proposed.

  On the other hand, since the flexible printed circuit board is a wiring board having a thickness of several tens to several hundreds of micrometers, when mounting a component, 0.5 to 2.0 mm reinforcement is required to ensure the support of the mounting part. A board is partially affixed on the base material surface of a flexible printed circuit board.

JP 2010-032743 A JP 2007-304543 A

On the other hand, there is a case where a reinforcing plate is attached on the protective film surface for the purpose of supporting the mounting portion of the flexible printed circuit board. In this case, in Patent Document 1, in the reflow mounting process for component mounting performed after attaching the reinforcing plate, the reflow mounting is insufficient because the adhesion between the reinforcing plate or the thermosetting adhesive and the photosensitive resin composition is insufficient. Problems such as swelling in the process (hereinafter referred to as reflow heat resistance) occur.
Similarly in Patent Document 2, there is a concern that sufficient reflow resistance cannot be obtained although it has heat press resistance.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention have, as a result, (A) a reinforcing plate, (B) a photosensitive resin composition, and (C) a flexible printed board integrated with a reinforcing plate. And (B) the photosensitive resin composition contains (D) a reactive surface conditioner, and has a configuration of a reinforcing plate-integrated flexible printed circuit board. It was found that the reflow heat resistance was secured even when a reinforcing plate was affixed on the object.

  That is, the reinforcing plate integrated flexible printed circuit board according to the present invention is a reinforcing plate integrated flexible printed circuit board configured in the order of (A) reinforcing plate, (B) photosensitive resin composition, and (C) flexible printed circuit board. The (B) photosensitive resin composition is characterized by containing (D) a reactive surface conditioner. Moreover, it is preferable that (B) the photosensitive resin composition contains (F) a carboxyl group-containing polymer, (G) an unsaturated double bond-containing resin, and (H) a photopolymerization initiator. When the total amount of the component (F), the component (G), and the component (H) is 100 parts by weight, (D) the reactive surface conditioner is 0.01 to 5 parts by weight. It is more preferable to contain.

  Moreover, it is preferable that (E) thermosetting adhesive exists between said (A) reinforcement board and (B) photosensitive resin composition.

  As described above, the present invention is a reinforcing plate-integrated flexible printed circuit board composed of (A) a reinforcing plate, (B) a photosensitive resin composition, and (C) a flexible printed circuit board in this order. Since the photosensitive resin composition contains (D) a reactive surface conditioner, even if a reinforcing plate is attached on the photosensitive resin composition, there is no effect such as occurrence of blistering during the reflow mounting process. It plays.

It is a figure which shows an example of a reinforcement board integrated flexible printed circuit board. It is the schematic diagram which has measured the curvature amount of the film.

  The present invention will be described in detail below.

  The reinforcing plate integrated flexible printed circuit board of the present invention is a reinforcing plate integrated flexible printed circuit board configured in the order of (A) reinforcing plate, (B) photosensitive resin composition, (C) flexible printed circuit board, The (B) photosensitive resin composition is a reinforcing plate-integrated flexible printed board containing (D) a reactive surface conditioner.

  Conventional reinforcement technology for flexible printed circuit boards for the purpose of reinforcement during component mounting was generally to attach a reinforcing plate on the base material surface or coverlay film material surface of the flexible printed circuit board. Thus, a technique for attaching a reinforcing plate on the surface of the photosensitive resin composition has also come out. In the case of the latter technique, since the adhesion between the reinforcing plate or the thermosetting adhesive and the photosensitive resin composition is insufficient, a decrease in reflow heat resistance was confirmed in the reflow mounting process.

  Here, it has been found that the reinforcing printed circuit board integrated flexible printed circuit board of the present invention does not cause defects such as swelling during reflow mounting even though the reinforcing plate is attached on the photosensitive resin composition. This is presumed to be due to the following reasons. That is, (D) the reactive surface conditioner reacts with any of the components of (B) the photosensitive resin composition at the time of UV irradiation or heat curing, so that the bleedout of the surface conditioner component on the surface of the cured film is caused. It is speculated that formation of a layer that is suppressed and inhibits reflow heat resistance can be suppressed, and reflow heat resistance is improved.

  Hereinafter, the reinforcing plate integrated flexible printed circuit board of the present invention will be described. In addition, (A) a reinforcing plate, (B) a photosensitive resin composition, (C) a flexible printed board, and other components will be described.

[Reinforcing plate integrated flexible printed circuit board]
The configuration of the flexible printed board integrated with a reinforcing plate of the present invention is shown in FIG. 1, but is not limited thereto. (B) A photosensitive resin composition (4) is applied onto a (C) flexible printed circuit board (1) comprising a base substrate (2) and a conductor circuit (3), and is exposed, developed and cured (B ) A cured film of the photosensitive resin composition is prepared. Thereafter, (A) the reinforcing plate (6) is bonded to the surface of the (B) photosensitive resin composition (4), and the reinforcing plate-integrated flexible printed circuit board is produced by heating and pressing. At this time, when (E) thermosetting adhesive (5) is used, first, (E) thermosetting adhesive (5) is temporarily pressure-bonded onto the surface of (B) photosensitive resin composition (4). At this time, the (E) thermosetting adhesive (5) is in a semi-cured state. Thereafter, (E) the reinforcing plate (6) is bonded to the surface of the (E) thermosetting adhesive (5), and heat-press molding is performed to produce a reinforcing plate-integrated flexible printed board. In this step, (E) the thermosetting adhesive (5) is completely cured to ensure sufficient adhesion. By adopting the above configuration, the flexible printed circuit board can be reinforced at the time of component mounting, and a decrease in reflow heat resistance during the reflow mounting process can be prevented. Here, (E) Temporary pressure-bonding conditions for the thermosetting adhesive can be selected as appropriate. For example, the heating temperature is preferably 80 ° C. to 180 ° C. and the pressure is preferably 0.1 MPa to 10 MPa. Is more preferably 100 ° C. to 150 ° C. and the pressure is 0.1 MPa to 1.0 MPa. When the temporary pressure bonding condition falls below the above range, there may be a problem that sufficient adhesion between (E) the thermosetting adhesive and (B) the photosensitive resin composition cannot be obtained. On the other hand, when the temporary pressure bonding conditions exceed the above range, (E) the thermosetting of the thermosetting adhesive proceeds and (A) sufficient adhesiveness cannot be ensured at the time of heat-press molding with the reinforcing plate There is. Further, (A) The heating and pressing molding conditions for bonding the reinforcing plates can be appropriately selected. For example, the heating temperature condition is preferably 100 ° C. to 200 ° C. and the pressing condition is preferably 0.5 MPa to 10 MPa. More preferably, the heating condition is 150 ° C. to 180 ° C., and the pressing condition is 0.5 MPa to 1 MPa. When the pressure molding condition falls below the above range, there may be a problem that sufficient adhesion cannot be obtained or heat-press molding takes time. On the other hand, when the heating and pressing molding conditions exceed the above range, there is a concern that the warping of the reinforcing plate-integrated flexible printed circuit board after the heating molding becomes large.

[(A) Reinforcing plate]
The (A) reinforcing plate in the present invention is not limited as long as it is a material used for the purpose of reinforcing the flexible printed circuit board. However, it may be used properly depending on the application. For example, as a thick reinforcing plate material, there are paper phenol, glass / epoxy plate, as a thin reinforcing plate material, polyimide film, polyester film, etc., and as a thin reinforcing plate material, a metal plate (copper plate, Aluminum plate). Moreover, the reinforcement board integrated wiring board excellent in heat resistance and a softness | flexibility can be obtained by using a polyimide film for a reinforcement board. Although it can select suitably as a polyimide film, thickness 75micrometer to 225micrometer is preferable, for example, Kaneka Co., Ltd. brand name Apical 125NPI (thickness 125micrometer) is mentioned. When the thickness of the said polyimide film is smaller than 75 micrometers, the supportability required in order to support the (C) flexible printed circuit board may not be acquired. On the other hand, when the thickness is larger than 225 μm, the overall thickness of the reinforcing plate-integrated flexible printed board becomes too large, and there is a concern that it is contrary to the trend toward miniaturization and weight reduction.

  On the other hand, when (A) the reinforcing plate is bonded to (B) the photosensitive resin composition, (E) a thermosetting adhesive may be used. As said (E) thermosetting adhesive, if it is a general thermosetting adhesive, it can select suitably, For example, an epoxy-type or acrylic type thermosetting adhesive is mentioned. Moreover, you may use either a sheet form and a solution form. When the thermosetting adhesive is in the form of a solution, (B) it may be applied to the surface of the cured film of the photosensitive resin composition or (A) it may be applied to the reinforcing plate, but it can be appropriately selected.

[(B) Photosensitive resin composition]
The photosensitive resin composition (B) in the present invention contains (D) a reactive surface conditioner, can draw a wiring pattern by development and exposure, and can fulfill a function required as an insulating protective film. Even if (A) the reinforcing plate is pasted on the photosensitive resin composition (B), it is not limited as long as no defect such as swelling occurs during reflow mounting. Here, the required functions include fine processing, development with a dilute alkaline aqueous solution, curing at a low temperature (200 ° C. or less), and a cured film obtained with high flexibility and electrical insulation. It is excellent in reliability, solder heat resistance, organic solvent resistance and flame retardancy, and the warpage of the substrate after curing is small.

  Examples of the material capable of fulfilling the required functions include (A) a photosensitive resin composition, (D) a reactive surface conditioner, (F) a carboxyl group-containing polymer, and (G) an unsaturated double bond-containing resin. And (H) a photopolymerization initiator. Hereinafter, (D) a reactive surface conditioner, (F) a carboxyl group-containing polymer, (G) an unsaturated double bond-containing resin, and (H) a photopolymerization initiator will be described.

<(D) Reactive surface conditioner>
The (D) reactive surface conditioner in the present invention is at least a bubble-breaking action, a foam-suppressing action with respect to bubbles generated when the photosensitive resin composition (B) in the present invention is applied on a substrate. It is a compound characterized by exhibiting any deaeration action and capable of reacting with any of (F) to (H) of the photosensitive resin composition. The bubble breaking action, foam suppressing action, and deaeration action in the present invention have the following meanings. Defoaming action means that the defoamer component with low surface tension penetrates into the foam film, and the surface tension of that part decreases locally, and this part is pulled from the surrounding foam film with high surface tension, and the foam is destroyed. It is an action to do. The antifoaming action means that the antifoam component, which has a small surface tension and is insoluble in the foaming liquid, is scattered on the surface of the foaming liquid that tries to form foam, so that foam with a uniform surface tension cannot be formed and foaming is suppressed. It is an action. Degassing action means that the defoamer component acts as an adhesive that bonds the bubbles inside the foamed liquid, and the joined internal bubbles become one large bubble that rises to the liquid surface due to its buoyancy, resulting in small bubbles. It is considered that bubbles larger than this state rise faster to the liquid surface, and the bubbles that emerge on the surface of the liquid are the action of breaking bubbles by the two interactions described above.

  The (D) reactive surface conditioner can be appropriately selected, but a polymer having at least one epoxy group at the side chain or terminal in the structure can be preferably used. For example, (meth) acrylic acid ester And an epoxy group-containing (meth) acrylic acid ester. As acrylic esters, (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2 -Methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-octoxyethyl (meth) acrylate, 2-lauroxyethyl (meth) acrylate, 2-phenoxyethyl (Meth) acrylate, 3-methoxybutyl (meth) acrylate, 4-methoxybutyl (meth) acrylate may be mentioned. There are many other types of monomers, but the number and types of monomers used are not limited as long as they are polymerizable and do not impair the physical properties of the surface conditioner. Examples of the epoxy group-containing (meth) acrylic acid ester include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 4-hydroxybutyl glycidyl ether acrylate. There are many other types of monomers, but the number and types of monomers used are not limited as long as they are polymerizable and do not impair the physical properties of the surface conditioner. The (D) reactive surface conditioner may be used alone or in combination of two or more.

  The preferable content of the component (D) in the present invention is preferably 0.01 to 5 parts by weight when the total amount of the component (F), the component (G), and the component (H) is 100 parts by weight. More preferably, it is 0.01 to 1 part by weight, and particularly preferably 0.01 to 0.5 part by weight.

  By adjusting the amount of the component (D) within the above range, the effect of removing bubbles generated when the photosensitive resin composition (B) is applied to the substrate can be sufficiently exerted and further cured. Since the reflow heat resistance of the cured film obtained by this can be improved, it is preferable. When the component (D) is less than the above range, a sufficient defoaming effect cannot be exhibited, and the production efficiency may deteriorate due to poor appearance of the coated surface. In addition, when the component (D) is larger than the above range, an unreacted (D) reactive antifoaming agent is present even after UV irradiation or at the time of thermosetting, so an adhesion inhibiting layer is formed and reflow heat resistance May lead to a decline in sex. Therefore, in order to maintain the appearance and production efficiency during coating and reflow heat resistance, it is preferable to adjust within the above range.

<(F) Carboxyl group-containing polymer>
The (F) carboxyl group-containing polymer in the present invention is a polymer having at least one carboxyl group in the molecule and having a weight average molecular weight of 3,000 to 300,000 in terms of polyethylene glycol. Here, the molecular weight of the (F) carboxyl group-containing polymer can be measured, for example, by the following method.
Equipment used: Tosoh HLC-8220GPC equivalent column: Tosoh TSK gel Super AWM-H (6.0 mm ID x 15 cm) x 2 guard columns: Tosoh TSK guard column Super AW-H
Eluent: 30 mM LiBr + 20 mM H3PO4 in DMF
Flow rate: 0.6 mL / min
Column temperature: 40 ° C
Detection conditions: RI: Polarity (+), Response (0.5 sec)
Sample concentration: about 5 mg / mL
Standard product: PEG (polyethylene glycol)

  By controlling the weight average molecular weight within the above range, (B) the alkali developability of the photosensitive resin composition, the flexibility of the resulting cured film, and the chemical resistance are preferable. When the weight average molecular weight is 3,000 or less, flexibility and chemical resistance may be lowered. When the weight average molecular weight is 300,000 or more, alkali developability is lowered. (B) Photosensitive resin composition The viscosity of the product may increase.

  The acid value of the (F) carboxyl group-containing polymer in the present invention can be measured, for example, by the method defined in JIS K5601-2-1, preferably 50 to 200 mgKOH / g, and preferably 50 to 150 mgKOH / g. More preferably, g is used. When the acid value is less than 50 mgKOH / g, the alkali developability of the photosensitive resin composition (B) may be reduced. When the acid value is more than 200 mgKOH / g, the hygroscopic property of the cured film increases and the electrical insulation reliability decreases. There is a case.

  More specifically, the carboxyl group-containing polymer (F) in the present invention is not particularly limited. For example, a carboxyl group-containing (meth) acrylic copolymer, a carboxyl group-containing vinyl copolymer, and an acid-modified polymer. Examples include polyurethane, acid-modified polyester, acid-modified polycarbonate, acid-modified polyamide, and acid-modified polyimide, and these can be used alone or in combination of two or more.

  The (F) carboxyl group-containing polymer in the present invention is not particularly limited as long as it has the structure described above, but more preferably, at least (meth) acrylic acid and alkyl (meth) acrylate. What copolymerized ester is used. By adopting such a structure, a photosensitive resin composition having excellent photosensitivity and excellent cured film flexibility and chemical resistance is preferable.

  The (meth) acrylic acid alkyl ester is a compound having an alkyl group having 1 to 20 carbon atoms in the ester chain of the (meth) acrylic acid ester, for example, methyl (meth) acrylate, ethyl (meth) acrylate. , (Meth) butyl acrylate, (Meth) acrylate isobutyl, (Meth) acrylate tertiary butyl, (Meth) acrylate hexyl, (Meth) acrylate 2-ethylhexyl, (Meth) octyl acrylate, (Meth) Nonyl acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like can be used, and these can be used alone or in combination of two or more. Among these (meth) acrylic acid alkyl esters, the use of methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate is particularly flexible for the cured film of the photosensitive resin composition (B). From the viewpoints of safety and chemical resistance.

  The above-mentioned reaction for copolymerizing at least (meth) acrylic acid and (meth) acrylic acid alkyl ester can proceed, for example, by generating radicals with a radical polymerization initiator. Examples of the radical polymerization initiator include azo compounds such as azobisisobutyronitrile, azobis (2-methylbutyronitrile), 2,2′-azobis-2,4-dimethylvaleronitrile, t-butylhydro Organic peroxides such as peroxide, cumene hydroperoxide, benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, peracid number Hydrogen etc. are mentioned, These can be used individually or in combination of 2 or more types.

  The amount of the radical polymerization initiator used is preferably 0.001 to 5 parts by weight and more preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the monomer used. When the amount is less than 0.001 part by weight, the reaction hardly proceeds, and when the amount is more than 5 parts by weight, the molecular weight may be lowered.

  The above reaction can be carried out in the absence of a solvent, but in order to control the reaction, it is desirable to carry out the reaction in a solvent system. For example, as the solvent, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N -Formamide solvents such as dimethylformamide and N, N-diethylformamide; Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide; N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone And pyrrolidone solvents such as hexamethylphosphoramide and γ-butyrolactone. Further, if necessary, these organic polar solvents can be used in combination with an aromatic hydrocarbon such as xylene or toluene.

  Furthermore, for example, methyl monoglyme (1,2-dimethoxyethane), methyldiglyme (bis (2-methoxyether) ether), methyltriglyme (1,2-bis (2-methoxyethoxy) ethane), methyltetraglyme (Bis [2- (2-methoxyethoxyethyl)] ether), ethyl monoglyme (1,2-diethoxyethane), ethyldiglyme (bis (2-ethoxyethyl) ether), butyldiglyme (bis (2 Symmetric glycol diethers such as -butoxyethyl) ether), 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 Cetate (aka carbitol acetate, 2- (2-butoxyethoxy) ethyl acetate)), diethylene glycol monobutyl ether acetate, 3-methoxybutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether Acetates such as acetate, propylene glycol diacetate, 1,3-butylene glycol diacetate, dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripylene glycol n Propyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, 1,3-dioxolane, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, a solvent may be used ethers such as ethyl ether also ethylene glycol. Of these, symmetrical glycol diethers are preferably used because side reactions are unlikely to occur.

  The amount of solvent used in the reaction is preferably such that the solute weight concentration in the reaction solution, that is, the solution concentration is 5% to 90% by weight, and is 20% to 70% by weight. It is more preferable. When the solution concentration is less than 5%, the polymerization reaction is difficult to occur and the reaction rate is lowered, and a desired structural substance may not be obtained. When the solution concentration is more than 90% by weight, the reaction solution has a high viscosity. And the reaction may be non-uniform.

  The reaction temperature is preferably 20 to 120 ° C, and more preferably 50 to 100 ° C. When the temperature is lower than 20 ° C., the reaction time becomes too long, and when it exceeds 120 ° C., gelation due to rapid progress of reaction or three-dimensional crosslinking accompanying side reaction may be caused. The reaction time can be appropriately selected depending on the scale of the batch and the reaction conditions employed.

<(G) Unsaturated double bond-containing resin>
The (G) unsaturated double bond-containing resin in the present invention is a resin in which a chemical bond is formed by (H) a photopolymerization initiator. Furthermore, the unsaturated double bond is an acryl group (CH ₂ ═CH— group), a methacryloyl group (CH═C (CH ₃ ) — group) or a vinyl group (—CH═CH— group). Is preferred. Examples of (G) unsaturated double bond-containing resins used in the present invention 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 hexaa Lilate, 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, 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-methacryloxypropane, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, methoxydipropylene glycol methacrylate, Toxitriethylene glycol acrylate, nonyl phenoxy polyethylene glycol acrylate, nonyl phenoxy polypropylene glycol acrylate, 1-acryloyloxypropyl-2-phthalate, isostearyl acrylate, polyoxyethylene alkyl ether acrylate, nonyl phenoxy ethylene 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 dimethacrylate, 1,4-cyclohexanedimethanol dimethacrylate, dipropylene glycol Cole 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 tetra Acrylate, propoxylated pentathritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol polyacrylate, triallyl isocyanurate, glycidyl methacrylate Rate, glycidyl allyl ether, 1,3,5-triacryloylhexahydro-s-triazine, triallyl 1,3,5-benzenecarboxylate, triallylamine, triallyl citrate, triallyl phosphate, arborbital, diallylamine, diallyl Dimethylsilane, 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′-isopropylidenediphenol diacrylate and the like are preferable, but 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, (B) 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, (B) stress hardly remains in the cured film obtained by curing the photosensitive resin composition, and (C) curling of the flexible printed circuit board can be suppressed when laminated on the flexible printed circuit board. Has characteristics.

  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 (1)

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

(Wherein 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)

(Wherein a + b + c = 3.6), a compound represented by the following formula (6)

A compound represented by the following general formula (7)

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

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

  In addition, any (G) unsaturated double bond-containing 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, as the (G) unsaturated double bond-containing resin, it is possible to use one kind, but using two or more kinds in combination improves the heat resistance of the cured film after photocuring. preferable.

  The (G) unsaturated double bond-containing resin in the present invention is blended so as to be 10 to 200 parts by weight with respect to 100 parts by weight of the component (F). This is preferable in terms of improving the photosensitivity.

  When the component (G) is less than the above range, (B) the alkali resistance of the cured film after photocuring the photosensitive resin composition is lowered, and the contrast when exposed and developed is difficult to attach. There is. Moreover, when there are more (G) components than the said range, since the stickiness of the coating film obtained by apply | coating the solution of the (B) photosensitive resin composition on a base material and drying a solvent becomes large. If the productivity is lowered and the crosslinking density is too high, the cured film may be brittle and easily cracked. By making it within the above range, the resolution at the time of exposure / development can be set to an optimum range.

<(H) Photopolymerization initiator>
The (H) photopolymerization initiator in the present invention is a compound that is activated by energy such as UV and initiates and accelerates the reaction of the (G) unsaturated double bond-containing resin. Examples of the (H) 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, benzyldimethyl Ketal, 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-methylcyclohexanone, 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-hydroxyethoxy)- Enyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -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-cyclopentadiene -1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium, 1,2- Kutandione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], iodium, (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) etc. are mentioned. The (H) photopolymerization initiator is preferably selected as appropriate, and is preferably used by mixing one or more.

  The (H) photopolymerization initiator in the present invention is preferably blended in an amount of 0.1 to 50 parts by weight with respect to a total of 100 parts by weight of the (F) component and the (G) component.

  Since the photosensitivity of the (B) photosensitive resin composition improves by making it the said mixture ratio, it is preferable.

  When the component (H) is less than the above range, the reaction of the radical polymerizable group at the time of light irradiation hardly occurs and the curing is often insufficient. Moreover, when there are more (H) components than the said range, adjustment of light irradiation amount becomes difficult and it may be in an overexposed state. Therefore, in order to advance the photocuring reaction efficiently, it is preferable to adjust within the above range.

<Other ingredients>
In the photosensitive resin composition (B) in the present invention, additives such as a thermosetting resin, a flame retardant, a colorant, an adhesion imparting agent, a polymerization inhibitor, and a solvent can be used as necessary. .

  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, unsaturated polyester resin; allyl on the side chain or terminal of 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. What is necessary is just to use combining the said thermosetting component 1 type (s) or 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 the cured film obtained by curing the photosensitive resin composition (B), and adhesion to a conductor such as a metal foil or a circuit board can be imparted. Can do. 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, DIC manufactured by Nippon Kayaku Co., Ltd. Product names Epicron 830 and Epicron 835 manufactured by 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. As Epiklon EXA-1514 and hydrogenated bisphenol A type epoxy resin, trade names jERYX8000, jERYX8034, jERYL7170, and ADEKA RESIN EP-408 manufactured by ADEKA Corporation are available. E, DIC Corporation trade name Epicron EXA-7015, Toto Kasei Co., Ltd. trade name Epototo YD-3000, Epototo YD-4000D, biphenyl type epoxy resin, Japan Epoxy Resin Corporation trade name jERYX4000, jERYL6121H, jERYL6640, jERYL6667, Nippon Kayaku Co., Ltd. trade name NC-3000, NC-3000H, phenoxy type epoxy resin, Japan Epoxy Resin Co., Ltd. trade name jER1256, jER4250, jER4275, naphthalene type epoxy resin Are DIC Corporation trade names Epicron HP-4032, Epicron HP-4700, Epicron HP-4200, Nippon Kayaku Co., Ltd. trade names NC-7000L, Phenol As the borak type epoxy resin, trade names jER152 and jER154 manufactured by Japan Epoxy Resin Co., Ltd., trade names EPPN-201-L manufactured by Nippon Kayaku Co., Ltd., trade names Epicron N-740 manufactured by DIC Corporation, and Epicron N- 770, product names Epototo YDPN-638 manufactured by Tohto Kasei Co., Ltd., and cresol novolak type epoxy resins include product names EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, DIC shares manufactured by Nippon Kayaku Co., Ltd. Brand names EPIKRON N-660, Epicron N-670, Epicron N-680, Epicron N-695, and trisphenol methane type epoxy resins manufactured by the company include trade names EPPN-501H and EPPN-501HY manufactured by Nippon Kayaku Co., Ltd. EPPN-502H, As the cyclopentadiene type epoxy resin, trade name XD-1000 manufactured by Nippon Kayaku Co., Ltd., the product name Epicron HP-7200 manufactured by DIC Co., Ltd., and as the amine type epoxy resin, trade name Epototo YH- of Toto Kasei Co., Ltd. 434, Epototo YH-434L, as flexible epoxy resin, trade names jER871, jER872, jERYL7175, jERYL7217, manufactured by Japan Epoxy Resin Co., Ltd., trade name Epicron EXA-4850, manufactured by DIC Corporation, and urethane-modified epoxy resin Adeka Resin EPU-6, Adeka Resin EPU-73, Adeka Resin EPU-78-11, Adeka Resin EPR-4023, Adeka Resin EPR-4023, Adeka Resin Resin EPR-4026, Adeka Resin EPR-1309, as a chelate-modified epoxy resin, ADEKA Corporation under the trade name Adeka Resin EP-49-10, and the like Adecaresin EP-49-20.

  The curing agent of the thermosetting resin in the present invention is not particularly limited, and examples thereof include phenol resins such as phenol novolac resin, cresol novolac resin, naphthalene type phenol resin, amino resin, urea resin, melamine, dicyandiamide, and the like. 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 present invention is preferably 0.5 to 100 parts by weight, more preferably 1 to 100 parts by weight of the total of the (F) component, the (G) component, and the (H) component. -50 parts by weight, particularly preferably 5-20 parts by weight. By adjusting the amount of the thermosetting resin component within the above range, (B) improving the heat resistance, chemical resistance and electrical insulation reliability of the cured film obtained by curing the photosensitive resin composition. Is preferable.
When there are few thermosetting resin components than the said range, the heat resistance of a cured film obtained by hardening the (B) photosensitive resin composition, and electrical insulation reliability may be inferior. Further, when the thermosetting resin component is larger than the above range, the cured film obtained by curing the photosensitive resin composition (B) becomes brittle and inferior in flexibility, and the warpage of the cured film also increases. There is.

The flame retardant in this invention is a compound used in order to make the (B) photosensitive resin composition flame-retardant. For example, a phosphoric ester compound, a halogen-containing compound, a metal hydroxide, an organic phosphorus compound, a silicone, or the like can be used, and the method of use can be used as an additive flame retardant or a reactive flame retardant. . Moreover, you may use a flame retardant suitably combining 1 type (s) or 2 or more types.
Among these, as the flame retardant, it is more preferable to use a non-halogen compound from the viewpoint of environmental pollution, and a phosphorus flame retardant is particularly preferable.

  The flame retardant component in the photosensitive resin composition (B) of the present invention is formulated so as to be 1 to 100 parts by weight with respect to a total of 100 parts by weight of the component (F), the component (G), and the component (H). It is preferable that

  The blending ratio is preferable because flame retardancy is improved without impairing the developability and photosensitivity of the photosensitive resin composition (B) and the bending resistance of the resulting cured film.

When there are few flame retardant components than the said range, the flame retardance of the cured film of (B) photosensitive resin composition may become inadequate. Moreover, when there are more flame retardant components than the said range, the developability and photosensitivity of (B) photosensitive resin composition may fall.
As colorants in the present invention, phthalocyanine compounds, azo compounds, carbon black, titanium oxide, adhesion imparting agents, silane coupling agents, triazole compounds, tetrazole compounds, triazine compounds, polymerization inhibitors These include hydroquinone, hydroquinone monomethyl ether and the like, and these can be used alone or in combination of two or more. Moreover, an inorganic filler can be used in the photosensitive resin composition (B) of the present invention 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.

  The solvent in the present invention may be any solvent that can dissolve (F) to (H). For example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, methyl monoglyme (1,2-dimethoxyethane), methyl diglyme (bis (2-methoxyether) ether), methyl triglyme (1,2-bis (2) -Methoxyethoxy) ethane), methyltetraglyme (bis [2- (2-methoxyethoxyethyl)] ether), ethyl monoglyme (1,2-diethoxyethane), ethyldiglyme (bis (2-ethoxyethyl)) Ether), symmetric glycol diethers such as butyl diglyme (bis (2-butoxyethyl) ether), γ-butyrolactone, methyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate , Et 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, ethylene glycol monomethyl ether acetate, ethylene glycol Acetates such as 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, Dipropylene glycol n-propyl ether, propylene glycol n -Butyl ether, dipropylene glycol n-butyl ether, tripylene glycol n-propyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, 1,3-dioxolane, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol Examples include ethers such as monoethyl ether, and these can be used alone or in combination of two or more.

  The solvent in the present invention is 10 to 400 parts by weight, more preferably 20 to 200 parts by weight, particularly preferably 100 parts by weight of (F) component, (G) component, and (H) component. 40 to 100 parts by weight.

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

  When the solvent is less than the above range, the viscosity of the photosensitive resin composition (B) becomes very high, making coating difficult, and inferior foam entrainment and leveling at the time of coating may occur. Moreover, when there are more solvents than the said range, the viscosity of (B) photosensitive resin composition will become very low, coating will become difficult and circuit coverage may be inferior.

  The photosensitive resin composition (B) in the present invention is obtained by uniformly mixing the components (F) to (H), the component (D) and other 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 (B) photosensitive resin composition in this invention can form a pattern as follows. First, the photosensitive resin composition is applied onto a substrate and dried to remove the 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 less, 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. Next, the pattern can be obtained by washing the unexposed portion with a developing solution using various methods such as shower, paddle, dipping or ultrasonic waves. 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, trii Propylamine 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 (B) in the present invention is preferably 0.01 to 10% by weight, particularly preferably 0.05 to 5% by weight. It is preferable to do. The temperature of the developer depends on the composition of the photosensitive resin composition (B) and 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 at a temperature of 0 ° C or lower.

  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.

  The pattern comprising a cured film formed from the photosensitive resin composition (B) in the present invention is excellent in heat resistance, flame retardancy, electrical and mechanical properties, and 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 printed circuit board. 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.

<(F) Carboxyl group-containing polymer>
[Synthesis Example 1]
A reaction vessel equipped with a stirrer, thermometer, dropping funnel, and nitrogen introduction tube was charged with 100.0 g of methyltriglyme (= 1,2-bis (2-methoxyethoxy) ethane) as a solvent for polymerization, under a nitrogen stream. The temperature was raised to 80 ° C. with stirring. To this, 12.0 g (0.14 mol) of methacrylic acid, 28.0 g (0.16 mol) of benzyl methacrylate, 60.0 g (0.42 mol) of butyl methacrylate, previously mixed at room temperature, As a radical polymerization initiator, 0.5 g of azobisisobutyronitrile was added dropwise from a dropping funnel over 3 hours while keeping the temperature at 80 ° C. After completion of the dropwise addition, the reaction solution was heated to 90 ° C. while stirring, and further stirred for 2 hours while maintaining the temperature of the reaction solution at 90 ° C. to obtain a carboxyl group-containing polymer solution of the present invention (F-1). The resulting carboxyl group-containing resin solution had a solid content concentration of 48%, a weight average molecular weight of 48,000, and an acid value of 78 mgKOH / g. The solid content concentration, weight average molecular weight, and acid value were measured by the following methods.

<Concentration of solid content>
The measurement was performed according to JIS K 5601-1-2. The drying conditions were 150 ° C. × 1 hour.

<Weight average molecular weight>
The weight average molecular weight of the synthesized (F) carboxyl group-containing polymer was measured under the following conditions.
Equipment used: Tosoh HLC-8220GPC equivalent column: Tosoh TSK gel Super AWM-H (6.0 mm ID x 15 cm) x 2 guard columns: Tosoh TSK guard column Super AW-H
Eluent: 30 mM LiBr + 20 mM H3PO4 in DMF
Flow rate: 0.6 mL / min
Column temperature: 40 ° C
Detection conditions: RI: Polarity (+), Response (0.5 sec)
Sample concentration: about 5 mg / mL
Standard product: PEG (polyethylene glycol)

<Acid value>
The acid value of the synthesized (F) carboxyl group-containing polymer was measured in accordance with JIS K 5601-2-1.

<(D) Synthesis of Reactive Surface Conditioner>
[Synthesis Example 2]
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introducing tube was charged with 80.0 g of xylene and heated to 105 ° C. while stirring under a nitrogen stream. Then, a mixed solution of 170.0 g of lauryl methacrylate, 115.0 g of 2-ethylhexyl acrylate, 15.0 g of 3,4-epoxycyclohexylmethyl (meth) acrylate, and 4.0 g of tert-butylperoxy 2-ethylhexite was added to the dropping funnel. Was added dropwise at a constant rate in 2 hours. After completion of the dropwise addition, the mixture was reacted at 105 for 1 hour, heated to 115 ° C., and reacted for 4 hours to obtain a polymer (D-1). The weight average molecular weight of this polymer was 30,000. The weight average molecular weight was measured by the apparatus and method described above.

[Synthesis Example 3]
Except that the mixed solution was changed to 170.0 g of lauryl methacrylate, 115.0 g of 2-ethylhexyl acrylate, 15.0 g of 4-hydroxybutyl glycidyl ether acrylate, and 4.0 g of tert-butylperoxy 2-ethylhexite [Synthesis Example 2], a polymer was obtained by the same synthesis method (D-2). The weight average molecular weight of this polymer was 35,000.

(Examples 1 and 2)
<Preparation of photosensitive resin composition>
(F) carboxyl group-containing polymer obtained in Synthesis Example 1, (G) photosensitive resin, (H) photopolymerization initiator, (D) reactive surface conditioner obtained in Synthesis Examples 2 and 3, and others These components were added to prepare a photosensitive resin composition. 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 resin solution synthesized in Synthesis Example 1 above. The following evaluation was carried out by completely defoaming the foam in the solution with a defoaming device.

<1> Product name NK ester A-9300 (ethoxylated isocyanuric acid triacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd.
<2> Product name NK ester BPE-1300 (bisphenol A EO-modified diacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. Molecular weight: 1684
<3> Product name of photopolymerization initiator manufactured by Ciba Specialty Chemicals <4> Product name of cresol novolac type polyfunctional epoxy resin manufactured by DIC Corporation <5> Product of flame retardant (phosphinic acid salt) manufactured by Clariant Name Average particle size: 2-3 μm Thermal decomposition start temperature: 300 ° C. or higher <6> Product name of silica particles manufactured by Nippon Aerosil Co., Ltd. <7> Antifoaming agent manufactured by Kyoeisha Chemical Co., Ltd.

<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 having 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 for exposure. 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 sufficiently washed with pure water, and then cured by heating in an oven at 160 ° C. for 90 minutes to prepare a cured film of the photosensitive resin composition.

<Evaluation of coating film>
The following items were evaluated for the coating film of the photosensitive resin composition. The evaluation results are shown in Table 2.

(I) Screen printability The screen printability of the photosensitive resin composition was evaluated by the following evaluation method.
Equipment used: Screen printer (Minomat 5575 manufactured by Mino Group)
Base material: Polyimide film (manufactured by Kaneka Corporation, Apical 25 NPI, thickness 25 μm)
Coating thickness: 30 μm
Screen mesh: Polyester 100 mesh Squeegee: Flat type, hardness 70 °
Printing speed: 100mm / sec
After screen printing under the above screen printing conditions to form a coating film, the coating film was observed after being left for 1 minute for determination.
○: The coating film does not contain bubbles ×: The coating film contains bubbles

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

(Ii) 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. Things Δ: A clear line width / space width = 100/100 μm photosensitive pattern is drawn on the surface of the polyimide film, and there is a fluctuation of the line due to peeling in the line portion, but there is a dissolution residue in the space portion. None x: Clear line width / space width = 100/100 μm photosensitive pattern is not drawn on the polyimide film surface, the line portion is peeled off, and dissolution residue is generated in the space portion thing

(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.
○: No abnormality in coating film ×: Abnormality such as swelling or peeling occurs in 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 10 times at 180 ° at 15 mm, and the coating film was visually confirmed to check for cracks.
○: The cured film has no cracks Δ: The cured film has some cracks ×: 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) Solder heat resistance By the same method as the above item <Preparation of coating film on polyimide film>, 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). 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%

(Vii) Warpage In the same manner as the above item <Preparation of coating film on polyimide film>, 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). 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.

(Viii) Flame retardancy In accordance with flame retardancy test standard UL94 for plastic materials, a flame retardance test was performed as follows. A cured film laminated film of a photosensitive resin composition was prepared on both sides 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>. 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 10 seconds to ignite. After 10 seconds, move away 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: Some samples do not extinguish within 10 seconds, or flame rises to the top of the sample and burns

(Ix) 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 an oily substance, 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

(X) Reflow heat resistance Etch out one-sided copper foil of flexible printed circuit board with copper foil on the entire surface with 12μm electrolytic copper foil overlapped on both sides in the same manner as the above item <Preparation of coating film on polyimide film> A cured film laminated film of the photosensitive resin composition was prepared on the surface of the copper foil on which the test piece remained. Further, a thermosetting adhesive (Du Pont Pyrrax LF0100) is temporarily pressure-bonded on a polyimide film (Kaneka 125NPI) with a hot roll laminating at 185 ° C. to produce a laminate 1. Thereafter, the photosensitive resin composition surface of the cured film laminated film of the photosensitive resin composition prepared above and the thermosetting adhesive surface of the laminated body 1 were pressure-bonded at 165 ° C./90 min by a hot press, and the laminated body 2 is produced. The appearance of the laminate after the reflow treatment of the produced laminate 2 under reflow conditions of 260 ° C.:peak top 260 ° C. × 20 sec is observed.
○: No change in appearance before and after the test ×: Swelling occurs at any laminate interface of the laminate after the test

(Comparative Example 1)
Photosensitive by adding (F) carboxyl group-containing polymer obtained in Synthesis Example 1, (G) component unsaturated double bond-containing resin, (H) component photopolymerization initiator, and other components. A 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. The foam in the solution was completely defoamed with the defoaming apparatus, and the physical properties of this composition were evaluated in the same manner as in Examples 1-2. The results are listed in Table 2.

(Comparative Example 2)
Kayrad ZFR1122 (trade name, manufactured by Nippon Kayaku Co., Ltd.) as an epoxy acrylate compound, 80 parts by mass, Kayrad DPHA (trade name, manufactured by Nippon Kayaku Co., Ltd.) as a diluent, 20 parts by mass, photopolymerization started 7 parts by mass of Irgacure 369 (Ciba Geigy, trade name; photopolymerization initiator 1) and 3 parts by mass of Kayacure DETXS (trade name; photopolymerization initiator 2), thermosetting component As an epoxy resin (content rate: 2.0%, epoxy equivalent: 300) 20 parts by mass, as a curing agent imidazole-based polymerization catalyst (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: 2E4MZ) 2 parts by mass and melamine 2 parts by mass, Barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: B-30) 10 parts by mass, 2 parts by mass of phthalocyanine blue, finely divided silica Nippon Aerosil Co., Ltd., trade name: Aerosil R972) 5 parts by mass, 5 parts by mass of phenoxyphosphazene oligomer (melting point: 110 ° C.) and 10 parts by mass of polyimide resin are mixed and kneaded by a three-roll mill. A mold resin composition was prepared. The foam in the solution was completely defoamed with the defoaming apparatus, and the physical properties of this composition were evaluated in the same manner as in Examples 1-2. The results are listed in Table 2. The polyimide resin used here was synthesized by the following synthesis method. Moreover, the epoxy resin obtained by the synthesis | combining method described after that was also used for the epoxy resin as a thermosetting component.

(Synthesis of polyimide resin)
In a 20-liter flask equipped with a stirrer, thermometer and condenser, 4951 g of diethylene glycol monoethyl ether acetate (hereinafter referred to as EDGA) and a polyisocyanate having an isocyanurate ring derived from isophorone diisocyanate (manufactured by Daicel-Hulus) , Trade name: T1890 / 100; isocyanate group content 18.2%, isocyanurate ring-containing triisocyanate content 85%, hereinafter referred to as IPDI-N.) 2760 g (12 mol as isocyanate group) and polytail HA ( Product name: Hydrogenated liquid polybutadiene having hydroxyl groups at both ends (having a linear hydrocarbon structure with a number average molecular weight of 2100), hydroxyl value 51.2 mgKOH / g) 2191 g (2 mol as hydroxyl group) Were charged, the temperature was increased to note that 80 ° C. to heating while stirring, reaction was conducted for 3 hours. Next, 1536 g of EDGA and 1536 g (8 mol) of trimellitic anhydride (hereinafter referred to as TMA) were charged, and the temperature was raised to 160 ° C., followed by reaction for 4 hours. The reaction proceeded with foaming. The system became a light brown clear liquid, and a polyimide resin solution was obtained.

(Synthesis of epoxy resin)
481.7 parts by mass of YDPN-638 (trade name; phenol novolac type epoxy resin, epoxy equivalent: 180.7) as non-halogen epoxy resin, HCA (manufactured by Sanko Co., Ltd.) as a phosphorus-containing compound , Phosphorus content 14.4%) 518.3 parts by mass, triphenylphosphine (manufactured by Hokuko Chemical Co., Ltd.) 1.04 parts by mass as a catalyst, stirrer, thermometer, cooling pipe, nitrogen gas introduction device Was added to a four-necked glass separable flask equipped with a reaction pressure of 160 to 190 ° C. and stirred for 8 hours at normal pressure, with an epoxy equivalent of 300, a softening point of 130 ° C., and a phosphorus content of 2.0. % 993 parts by mass of a phosphorus-containing solid epoxy resin was obtained.

DESCRIPTION OF SYMBOLS 1 (C) Flexible printed circuit board 2 Base base material 3 Conductor circuit 4 (B) Photosensitive resin composition 5 (E) Thermosetting adhesive 6 (A) Reinforcement board 7 Polyimide film which laminated the photosensitive resin composition 8 Warping amount 9 Smooth base

Claims (4)

  (A) Reinforcing plate, (B) photosensitive resin composition, (C) Reinforcing plate-integrated flexible printed circuit board configured in this order, wherein (B) the photosensitive resin composition is (D ) A reinforcing plate-integrated flexible printed board comprising a reactive surface conditioner.   (A) Reinforcing plate, (E) Thermosetting adhesive, (B) Photosensitive resin composition, (C) Reinforcing plate-integrated flexible printed circuit board constituted in this order, ) A flexible printed board integrated with a reinforcing plate, wherein the photosensitive resin composition contains (D) a reactive surface conditioner.   The (B) photosensitive resin composition comprises (F) a carboxyl group-containing polymer, (G) an unsaturated double bond-containing resin, and (H) a photopolymerization initiator. The reinforcing plate-integrated flexible printed circuit board according to any one of the above.   When (B) the photosensitive resin composition is 100 parts by weight of the total amount of the component (F), the component (G), and the component (H), the (D) reactive surface conditioner. The reinforcing plate-integrated flexible printed board according to claim 3, wherein 0.01 to 5 parts by weight is contained.

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