JP4461037B2 - Photosensitive resin composition and photosensitive resin laminate using the same - Google Patents

Description

  The present invention relates to a liquid solder resist used for a printed wiring board or the like, or a photosensitive resin composition used for a dry film type solder resist and a photosensitive resin laminate using the same, and more specifically, a flexible printed wiring board. Useful as a solder mask resist, conductive circuit followability, flexibility, developability, resolution, solder heat resistance, solvent resistance, alkali resistance, electrical insulation, and flame resistance The present invention relates to a resin composition and a photosensitive resin laminate using the same.

  In recent years, the use of so-called flexible printed wiring boards (FPC), in which printed wiring boards are folded and incorporated, has been increasing mainly in small electronic devices such as mobile phones and digital cameras.

  Like the conventional rigid type printed wiring board, the FPC also goes through a process of component mounting by soldering. At this time, the FPC circuit portion is protected and has permanent characteristics such as insulation. A cover layer having a function as a protective film is used. Examples of such a cover layer forming material include a cover lay film made of a polyimide resin provided with an adhesive layer, a cover coat ink for printing a liquid material having heat resistance, insulation, and the like. Since these cover layer forming materials are used for FPC, they are required to have flexibility to withstand bending mounting.

  However, when the cover lay film is used, it has to go through a process of punching out the soldered portion with a mold, which has a problem that it is complicated and expensive. On the other hand, in the case of cover coat ink, since it goes through the printing process, it is difficult to control the environmental load due to the solvent and the film thickness. Further, since the through hole cannot be tented, a development residue that must be embedded in advance is generated. It has problems such as easy.

  From such a point, recently, it has been proposed to use a photosensitive resin laminated body corresponding to a solder mask having performance as a cover coat. As the photosensitive resin laminate, for example, a photosensitive film in which a layer made of a photosensitive resin composition is formed on a support surface is used.

As such a photosensitive resin composition, light containing a specific acrylate functional urethane oligomer, a specific epoxy acrylate oligomer, and an acrylate functional oligomer in a binder polymer including a main chain formed from styrene and maleic anhydride. A photoimageable composition containing an imageable compound, aminoblast, and a photoinitiator has been proposed (see Patent Document 1).
JP 2000-47381 A

  However, the above composition does not satisfy all of the characteristics such as flexibility, followability to a conductor circuit, developability, solder heat resistance, and the like, and it is required to satisfy a higher level. It is the actual situation.

  The present invention has been made in view of such circumstances, and is excellent in all of flexibility, followability to a conductor circuit, developability, solder heat resistance, and further, resolution, solvent resistance, alkali resistance, It is an object of the present invention to provide a photosensitive resin composition exhibiting excellent electrical insulation properties and a photosensitive resin laminate using the same.

In order to achieve the above object, the present invention has a first gist of a photosensitive resin composition containing the following (A) to (D).
(A1) A carboxyl group-containing (meth) acrylic polymer having a weight average molecular weight of 100,000 to 250,000 and an acid value of 50 to 250 mgKOH / g.
(A2) A carboxyl group having a weight average molecular weight of 5,000 to 50,000, an acid value of 40 to 160 mgKOH / g, and containing 0.3 to 3.5 mmol / g of ethylenically unsaturated groups in the side chain Containing (meth) acrylic functional polymer.
(B) A (meth) acrylic monomer component having an ethylenically unsaturated group.
(C) Photopolymerization initiator.
(D) Amino resin.

  The present invention is also a photosensitive resin laminate in which a support film is laminated on one side of the photosensitive resin composition layer and a protective film is laminated on the other side of the photosensitive resin composition layer, The photosensitive resin laminated body in which the photosensitive resin composition layer is formed using the said photosensitive resin composition is made into the 2nd summary.

  That is, the present inventors are satisfied under higher conditions in all of flexibility, followability to a conductor circuit, developability, solder heat resistance, and further resolution, solvent resistance, alkali resistance, and electrical insulation. In order to obtain a light-sensitive photosensitive resin laminate, intensive research was repeated focusing on the photosensitive resin composition as the layer forming material. As a result, a polymer comprising a specific carboxyl group-containing (meth) acrylic polymer (A1) having a high molecular weight and a specific carboxyl group-containing (meth) acrylic functional polymer (A2) having a medium to low molecular weight. When component (A) is used, high moldability and flexibility are imparted by A1, and high followability to a conductive circuit and developability are imparted by A2, and A2 has a specific amount in the side chain. Thus, the present inventors have found that further solid cross-linking is formed and the solder heat resistance, solvent resistance, and alkali resistance are improved. More specifically, when only the above A1 is used as a polymer, it is good for obtaining high moldability and flexibility, but it is difficult to obtain compatibility with other components, and the developability tends to deteriorate. However, there is a problem that it is necessary to cope with the increase in temperature or the time as a lamination condition for following the conductor circuit. On the other hand, when only the above A2 is used, the followability to the conductive circuit and the developability are improved, and the solder heat resistance, solvent resistance, and alkali resistance tend to be improved. There is a problem that it is difficult to withstand the strength. Further, when laminated on a conductor circuit at a relatively high temperature, the resist film thickness on the conductor circuit becomes thin, and the solder heat resistance, solvent resistance, and alkali resistance may be inferior. Thus, in the present invention, by using the specific polymers of A1 and A2 in combination, the disadvantages can be compensated while taking advantage of both, and a desired effect can be obtained.

  Thus, the photosensitive resin composition of the present invention has a polymer component (A) mainly composed of a specific high molecular weight polymer (A1) and a specific medium to low molecular weight polymer (A2), and an ethylenically unsaturated group. Since it contains (meth) acrylic monomer component (B), photopolymerization initiator (C) and amino resin (D), it has flexibility, followability to conductor circuits, developability, resolution, solder Excellent heat resistance, solvent resistance, alkali resistance, and electrical insulation. Therefore, this photosensitive resin composition is useful as a photosensitive resin composition for solder resist. And the photosensitive resin laminated body in which the photosensitive resin composition layer which consists of this special photosensitive resin composition is formed between a support body film and a protective film is naturally excellent flexibility, This photosensitive resin laminate is useful as a solder resist laminate because it achieves followability to conductor circuits, developability, resolution, solder heat resistance, solvent resistance, alkali resistance, and electrical insulation. is there.

  When the urethane (meth) acrylate compound (B1) represented by the general formula (1) is contained as the (meth) acrylic monomer component (B) having the ethylenically unsaturated group, the flexibility is further improved. become.

  Moreover, when content of the said polymer component (A) is set to the specific range of the whole photosensitive resin composition except a solvent, the followable | trackability with respect to a conductor circuit improves especially.

  Furthermore, in addition to the above (A) to (D), when a specific phosphorus compound (E) is contained, excellent flame retardancy is imparted without using a halogen compound and an antimony compound, which are conventional flame retardants. It becomes like this.

  And even when the surface average roughness (Ra) on the photosensitive resin composition layer lamination surface side of the protective film of the photosensitive resin laminate of the present invention is 1.0 or more, air escape during lamination is good. The followability to the conductor circuit is further improved.

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

  The photosensitive resin composition of the present invention comprises a polymer component (A) mainly composed of two kinds of specific polymers, a (meth) acrylic monomer component (B) having an ethylenically unsaturated group, and photopolymerization initiation. It can be obtained using the agent (C) and the amino resin (D). The present invention is most characterized in that two types of polymers having different molecular weights are used as the polymer compound (A). In the present invention, (meth) acryl means both acryl and methacryl, and these are collectively referred to as “(meth) acryl”.

  The polymer component (A) is mainly composed of two types of specific polymers (A1, A2) having different molecular weights. In the present invention, the main component includes the case where the polymer component (A) is composed of only two kinds of specific polymers (A1, A2) having different molecular weights.

  Among the two specific polymers (A1, A2) having different molecular weights, one contains a carboxyl group having a weight average molecular weight (Mw) of 100,000 to 250,000 and an acid value of 50 to 250 mgKOH / g By using this carboxyl group-containing (meth) acrylic polymer (A1), which is a (meth) acrylic polymer (A1), high moldability and excellent flexibility can be imparted. The other has a weight average molecular weight (Mw) of 10,000 to 80,000, an acid value of 50 to 250 mgKOH / g, and an ethylenically unsaturated group in the side chain of 0.3 to 3. A carboxyl group-containing (meth) acrylic functional polymer (A2) containing 5 mmol / g, improved compatibility of each component, excellent followability to the conductor circuit, high developability and after embedding in the conductor circuit It is possible to impart an improvement in surface smoothness. And since it has the said ethylenically unsaturated group, it becomes possible to form a much stronger bridge | crosslinking structure, and also more excellent solder heat resistance, solvent resistance, alkali resistance, etc. are obtained.

  Examples of the high molecular weight carboxyl group-containing (meth) acrylic polymer (A1) having a weight average molecular weight (Mw) in the range of 100,000 to 250,000 include (meth) acrylic acid and (meth) acrylic acid. An ester copolymer is exemplified, and a copolymer of (meth) acrylic acid, (meth) acrylic ester and styrene is more preferred.

  Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Examples include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Among the above copolymers, (meth) acrylic acid ester having a homopolymer (homopolymer) having a glass transition temperature (Tg) of 20 ° C. or less in terms of flexibility and followability to a conductor circuit From the viewpoints of transparency and developability, a copolymer containing methyl methacrylate and methacrylic acid, preferably a copolymer further containing styrene is preferable. Examples of monomers having a glass transition temperature (Tg) of 20 ° C. or lower include methyl acrylate, ethyl acrylate, n-butyl (meth) acrylate, i-butyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, hydroxyethyl Examples thereof include acrylate and hydroxypropyl acrylate.

  Further, as described above, the weight average molecular weight (Mw) of the carboxyl group-containing (meth) acrylic polymer (A1) must be in the range of 100,000 to 250,000, particularly preferably 120. , 000-200,000. That is, when the weight average molecular weight (Mw) is less than 100,000, flexibility tends to be inferior. Conversely, when the weight average molecular weight (Mw) is more than 250,000, developability is deteriorated and resolution is deteriorated, or a residue is generated after development. This is because it tends to be easier.

  The carboxyl group-containing (meth) acrylic polymer (A1) must have an acid value of 50 to 250 mgKOH / g, particularly preferably an acid value of 120 to 240 mgKOH / g, as described above. . That is, when the acid value is less than 50 mgKOH / g, the resist developability tends to be insufficient, and when it exceeds 250 mgKOH / g, the fine line adhesion of the resist pattern tends to deteriorate.

  Next, a medium and low molecular weight carboxyl group-containing (meta) having a weight average molecular weight (Mw) in the range of 5,000 to 50,000, which is used together with the high molecular weight carboxyl group-containing (meth) acrylic polymer (A1). ) The acrylic functional polymer (A2) is characterized by containing 0.3 to 3.5 mmol / g of ethylenically unsaturated groups in the side chain. As such a carboxyl group-containing (meth) acrylic functional polymer (A2), a compound having an ethylenically unsaturated group is allowed to react with the carboxyl group-containing (meth) acrylic polymer, and the functional polymer (A2) The polymer prepared so that the amount of ethylenically unsaturated groups may be 0.3 to 3.5 mmol / g. The amount of the ethylenically unsaturated group is preferably 1.0 to 3.2 mmol / g, particularly preferably 1.5 to 3.2 mmol / g. That is, when the amount of the ethylenically unsaturated group is less than 0.3 mmol / g, the fine line adhesion of the resist pattern is inferior, and when it exceeds 3.5 mmol / g, the compatibility with other resist components is inferior or the flexibility is inferior. Because.

  As such a carboxyl group-containing (meth) acrylic functional polymer (A2), for example, a copolymer of (meth) acrylic acid and (meth) acrylic acid ester, (meth) acrylic acid ester and styrene, ) It can be obtained by reacting an acrylic acid copolymer or the like with a compound having an ethylenically unsaturated group.

  As said (meth) acrylic acid ester, as described above, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2- Examples include ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Among these, from the viewpoint of heat resistance and chemical resistance, a copolymer of methyl methacrylate / n-butyl methacrylate / methacrylic acid and methyl methacrylate / 2-hydroxyethyl methacrylate / methacrylic acid are preferable.

Examples of the compound having an ethylenically unsaturated group include an alicyclic epoxy group-containing unsaturated compound, an isocyanate group-containing unsaturated compound, a diisocyanate compound such as isophorone diisocyanate, and a hydroxyl group-containing unsaturated compound such as diethylene glycol monomethacrylate. And reactants. As said alicyclic epoxy group containing unsaturated compound, what is necessary is just a compound which has one radical polymerizable unsaturated group and alicyclic epoxy group in 1 molecule, for example, following General formula (2) The compound represented by-(13) and glycidyl (meth) acrylate are mentioned. In these general formulas, R ₁ represents hydrogen or a methyl group, R ₂ represents — [(CO) x CHX ₁ (CHX ₂ ) y O] z — (where x is 0 or 1, y is 0 to 9) An integer, z represents an integer of 1 to 10, and X ₁ and X ₂ represent hydrogen or a methyl group. Of the compounds represented by the general formulas (2) to (13), it is preferable to use the compound represented by the general formula (2) or glycidyl methacrylate from the viewpoint of production and stability during reaction.

  The carboxyl group-containing (meth) acrylic functional polymer (A2) is produced, for example, as follows. That is, a carboxyl group-containing (meth) acrylic polymer is dissolved in a solvent such as methyl ethyl ketone, toluene, xylene, ethyl acetate, isopropanol, propylene glycol monomethyl ether, and naphthenic acid, lauric acid, stearic acid, octoenoic acid is used as a catalyst. Using a metal salt of a carboxylic acid such as a lithium salt, chromium salt, zirconium salt, potassium salt, sodium salt, tin salt, and the like, and a carboxyl group in the carboxyl group-containing (meth) acrylic polymer and the alicyclic epoxy group What is necessary is just to make the epoxy group of a contained unsaturated compound react on the conditions for 1 to 20 hours at 30-80 degreeC, and the ratio of the reaction at that time is 40-80 mol% of a carboxyl group, Furthermore, 50-70 mol% What is necessary is just to set to about.

  The weight average molecular weight (Mw) of the carboxyl group-containing (meth) acrylic functional polymer (A2) must be in the range of 5,000 to 50,000, as described above. Preferably it is 8,000-40,000. That is, when the weight average molecular weight (Mw) is less than 5,000, flexibility tends to be inferior, and conversely, when it exceeds 50,000, the followability to the conductor circuit is inferior, and the carboxyl group-containing (meta) This is because the compatibility with the acrylic polymer (A1) is inferior and the smoothness of the resist pattern tends to be inferior, or the surface smoothness after embedding in a conductor circuit tends to be inferior.

  The carboxyl group-containing (meth) acrylic functional polymer (A2) must have an acid value of 40 to 160 mgKOH / g, particularly preferably an acid value of 45 to 145 mgKOH / g, as described above. It is. That is, when the acid value is less than 40 mg KOH / g, the resist peelability tends to be inferior, and when it exceeds 160 mg KOH / g, the compatibility with the carboxyl group-containing (meth) acrylic polymer (A1) is deteriorated, and the resist pattern is smooth. This is because the tendency to be inferior is seen.

  The combined ratio of the high molecular weight carboxyl group-containing (meth) acrylic polymer (A1) and the medium to low molecular weight carboxyl group-containing (meth) acrylic functional polymer (A2) is A1 / A2 = 30 by weight. It is preferable to set in the range of / 70 to 75/25, particularly preferably in the range of A1 / A2 = 40/60 to 70/30.

  In the present invention, the polymer component (A) includes the high molecular weight carboxyl group-containing (meth) acrylic polymer (A1) and the medium and low molecular weight carboxyl group-containing (meth) acrylic functional polymer (A2). When two types of (meth) acrylic polymers are used, the combination is not limited to one type of each, but may be a combination of one or more types of A1 and one or more types of A2.

  The content of the polymer component (A) is preferably set in the range of 25 to 45% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably 30 to 40 from the viewpoint of followability to the conductor circuit. % By weight. That is, if it is less than 25% by weight, the embedding property of the photosensitive resin composition between conductor circuits tends to be good, but when a laminate is produced using the photosensitive resin composition, the photosensitive resin The stickiness of the layer becomes too large, making it easier for air to enter when laminating to the conductor circuit, and when storing the photosensitive resin laminate in roll form, it tends to be wrinkled, or the photosensitive resin composition from the end face Due to easy exudation of material layers, storage stability is poor, there is a tendency to break without securing sufficient strength for tenting through holes, or the resist is too soft to be laminated on conductor circuits Occasionally, the resist flows and it is difficult to sufficiently form the insulating layer on the wiring, and the solder heat resistance, solvent resistance, alkali resistance, etc. tend to be reduced. On the contrary, if it exceeds 45% by weight, it becomes easy to form a space between the substrate and the photosensitive resin composition, and it becomes difficult to ensure sufficient insulation, or due to this space, This is because the photosensitive resin layer tends to peel off from the substrate.

  The (meth) acrylic monomer component (B) having an ethylenically unsaturated group used together with the polymer component (A) is not particularly limited, and is a (meth) acrylic monomer having an ethylenically unsaturated group. I just need it. And it is preferable to use 2 or more types of such monomer components. This is because by using a plurality of types in this manner, solder heat resistance, flexibility, chemical resistance and the like can be imparted in a balanced manner.

  As the (meth) acrylic monomer component (B) having an ethylenically unsaturated group, a urethane (meth) acrylate compound (B1) can be used. The (meth) acrylic monomer component (B) having an ethylenically unsaturated group is important for imparting curability by the action of the photopolymerization initiator (C) described later. ) It is preferable to use an acrylate compound (B1) because an excellent product in terms of flexibility can be obtained. Specific examples of the urethane (meth) acrylate compound (B1) include urethane (meth) acrylate compounds represented by the following general formula (1). By using the urethane (meth) acrylate compound represented by the general formula (1), good developability is imparted in addition to excellent flexibility.

In the general formula (1), R is preferably a methyl group, X is preferably —CH ₂ CH ₂ O—, and Y is preferably —CH ₂ CH (CH ₃ ) O—.

In the general formula (1), examples of the divalent hydrocarbon group having 2 to 20 carbon atoms represented by Z include the followings in addition to — (CH ₂ ) ₆ —. Of these, — (CH ₂ ) ₆ — is preferable.

  In the general formula (1), k is preferably an integer of 10 to 20, m is preferably an integer of 3 to 6, and n is preferably an integer of 3 to 6.

  The weight average molecular weight (Mw) of the urethane (meth) acrylate compound (B1) represented by the general formula (1) is preferably in the range of 1900 to 3500, particularly preferably 2400 to 3000.

And among the urethane (meth) acrylate compounds (B2) represented by the general formula (1), R = —CH ₃ , X = —CH ₂ CH ₂ O—, Y = —CH ₂ CH (CH ₃ ) O—, Z = — (CH ₂ ) ₆ —, k = 15, m = 6, n = 4 are particularly preferred.

  The content in the case of using the urethane (meth) acrylate compound (B1) is preferably set in the range of 1 to 20% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably to the conductor circuit. From the point of followability, it is 1.5 to 10% by weight. That is, if it is less than 1% by weight, the effect of imparting flexibility after curing the resist is poor, and if it exceeds 20% by weight, the solder heat resistance and chemical resistance tend to be inferior.

  Further, as the (meth) acrylic monomer component (B) having an ethylenically unsaturated group, a compound other than the urethane (meth) acrylate compound (B1) may be used, taking into consideration heat resistance and chemical resistance. Then, a bifunctional or higher functional compound may be used in combination with the urethane (meth) acrylate compound (B1). As the bifunctional or higher compound, for example, an epoxy (meth) acrylate compound containing at least two OH groups in one molecule can be used. By using the epoxy (meth) acrylate compound, as a result of the high temperature reaction (heat curing), it is possible to impart a high degree of cross-linking, and excellent heat resistance and solvent resistance can be obtained. And among the said epoxy (meth) acrylate compounds, it is preferable from a heat resistant point to use the bisphenol A modified | denatured type epoxy acrylate. Specific examples of such bisphenol A-modified epoxy acrylates include Shinbetsu UCB's “Ebecryl” series 600 series 645,648, 3412,3500, 3700 series 3701, etc. EA-1020,1025,1026,1028 etc. made from an industrial company are mention | raise | lifted. These compounds may be used alone or in combination of two or more.

  The content in the case of using the epoxy (meth) acrylate compound is preferably set in the range of 3 to 40% by weight of the entire photosensitive resin composition excluding the solvent, and particularly preferably the followability to the conductor circuit. From the point, it is 7.5 to 30% by weight. That is, if it is less than 3% by weight, the solder heat resistance tends to be inferior, and if it exceeds 40% by weight, the flexibility tends to decrease.

  Furthermore, in the present invention, as the (meth) acrylic monomer component (B) having an ethylenically unsaturated group, in addition to the urethane (meth) acrylate compound (B1) and the epoxy (meth) acrylate compound, another ethylene A (meth) acrylic monomer component having a polymerizable unsaturated group may be used. The (meth) acrylic monomer component having another ethylenically unsaturated group is not particularly limited, but in view of heat resistance and chemical resistance, it is preferable to use a bifunctional or higher polyfunctional compound. . Specifically, ethylene oxide-modified bisphenol A diacrylate, trimethylolpropane tripropoxy tri (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexane glycol di (meth) acrylate , Glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) a Relate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid modified neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, 1,6-hexa Methyl diglycidyl ether di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerin polyglycidyl ether poly (meth) acrylate, pentaerythritol tetra ( (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2,2'-bis (4- (meth) acryloxydiethoxyphenyl) Propane, 2,2'-bis (4- (meth) acryloxypentaethoxyphenyl) propane, 2,2'-bis (4- (meth) acryloxypolyethoxyphenyl) propane, 2-hydroxy-3- (meta And polyfunctional monomers such as acryloyloxypropyl acrylate and trimethylolpropane triglycidyl ether tri (meth) acrylate. In addition, an appropriate amount of a monofunctional monomer can be used in combination with the polyfunctional monomer. Examples of such a monofunctional monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerin mono ( Examples include meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, phthalic acid derivative half (meth) acrylate, and N-methylol (meth) acrylamide. These may be used alone or in combination of two or more.

  The total content of the (meth) acrylic monomer component (B) having the ethylenically unsaturated group is preferably set in the range of 40 to 60% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably. Is 42 to 58% by weight. That is, if it is less than 40% by weight, there is a tendency that solder heat resistance and chemical resistance after curing are inferior. On the contrary, if it exceeds 60% by weight, the stickiness of the photosensitive resin composition layer becomes too large, and it becomes easy for air to enter when laminating to a conductor circuit, or it is easy to be wrinkled when stored in a roll form. This is because there is a tendency that problems such as becoming easier to occur.

  The photopolymerization initiator (C) used together with the polymer component (A) and the (meth) acrylic monomer component (B) having an ethylenically unsaturated group is not particularly limited and conventionally known ones are used. . For example, benzoin ether, benzyl ketals, acetophenones, benzophenones, thioxanthones (2-isopropylthioxanthone, 2-ethylthioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, etc.), quinones, 2-methyl-1 -[4- (methylthio) phenyl] -2-morifornopropan-1-one, 9-phenylacridine and the like. These may be used alone or in combination of two or more. Among these, 2-methyl-1- [4- (methylthio) phenyl] -2-morifornopropan-1-one, 9-phenylacridine, 2,4-diethylthioxanthone, benzyldimethyl ketal, 2,4- Diethylthioxanthone is preferred, particularly 2-methyl-1- [4- (methylthio) phenyl] -2-morfornopropan-1-one, 9-phenylacridine and 2,4-diethylthioxanthone, The combined use of methyl-1- [4- (methylthio) phenyl] -2-morifornopropan-1-one, benzyldimethyl ketal and 2,4-diethylthioxanthone is preferred.

  The content of the photopolymerization initiator (C) is preferably set in the range of 1.5 to 15% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably 2.5 to 10% by weight. is there. That is, when the amount is less than 1.5% by weight, the sensitivity becomes insufficient and the (meth) acrylic monomer component (B) having the ethylenically unsaturated group tends not to be cured sufficiently. This is because when the amount exceeds wt%, defects such as inferior resolution are observed.

  The amino resin (D) used together with the polymer component (A), the (meth) acrylic monomer component (B) having an ethylenically unsaturated group and the photopolymerization initiator (C) has a high temperature (eg, 135 ° C. or higher). It is an important component for exerting an effect as a thermal crosslinking agent and imparting heat resistance, solvent resistance and the like. The amino resin (D) is not particularly limited as long as it is an amino group-containing compound, but a melamine resin compound is preferably used. Specific examples include the “Resimene” series manufactured by UCB, the “Cymel” series manufactured by CYTEC, and the like.

  The content of the amino resin (D) is preferably set in the range of 1 to 15% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably 2.5 to 10% by weight. That is, if the amount is less than 1% by weight, the solder heat resistance and the solvent resistance tend to be inferior. On the other hand, if the amount exceeds 15% by weight, the flexibility is lowered, and the odor tends to be a problem during use. This is because of

  In the present invention, in addition to the polymer component (A), the (meth) acrylic monomer component (B) having an ethylenically unsaturated group, the photopolymerization initiator (C) and the amino resin (D), A phosphorus compound (E) containing at least four phenoxy groups can be used. By using this phosphorus compound (E), high flame retardancy can be imparted. The phenoxy group here is a structure in which an oxygen atom is attached to the benzene ring, and there may be a substituent on the benzene ring. Examples of such phosphorus compounds (E) include phosphate ester compounds and phosphazene compounds.

  As the phosphate compound, aromatic condensed phosphates are preferably used.

  Examples of the phosphazene compound include diphenoxyphosphazene having a 3- to 7-membered ring structure, polydiphenoxyphosphazene, and the like.

  These phosphate ester compounds and phosphazene compounds are used alone or in combination of two or more.

  The content of the phosphorus compound (E) is preferably set in the range of 1 to 40% by weight of the entire photosensitive resin composition excluding the solvent, particularly preferably 1.5 to 1.5 in consideration of the balance of physical properties. 20% by weight.

  Furthermore, the photosensitive resin composition of the present invention includes the polymer component (A), a (meth) acrylic monomer component (B) having an ethylenically unsaturated group, a photopolymerization initiator (C), an amino resin (D ), And in addition to the phosphorus compound (E), pigments, dyes, antioxidants, adhesion promoters, light absorbers, leveling agents, flame retardants other than the phosphorus compound (E), fillers, antifoaming Other additives such as an agent can be appropriately blended as necessary. The content of such other additives is preferably set in a range of about 0.01 to 20% by weight of the entire photosensitive resin composition excluding the solvent.

  The photosensitive resin composition of the present invention comprises the polymer component (A), a (meth) acrylic monomer component (B) having an ethylenically unsaturated group, a photopolymerization initiator (C), an amino resin (D), and It can prepare by mix | blending and mixing a phosphorus compound (E) and another additive as needed. And at the time of use at the time of preparation of the below-mentioned photosensitive resin laminated body, it mixes and prepares so that it may become a predetermined density | concentration using an organic solvent, and is used.

Examples of the organic solvent include, but are not limited to, acetone, methyl ethyl ketone, methanol, isopropyl alcohol, propylene glycol monoethyl ether, ethyl acetate, butyl acetate, and the like. These may be used alone or in combination of two or more. Used. And as the density | concentration, although suitably set according to the construction method applied at the time of preparation of the below-mentioned photosensitive resin laminated body, and a viscosity, it is the range of 35 to 60 weight% of solid content normally.

  In this invention, the photosensitive resin laminated body which uses the said photosensitive resin composition is mention | raise | lifted. As the photosensitive resin laminate, a support film (carrier film) is laminated and formed on one side of a photosensitive resin composition layer obtained using the photosensitive resin composition. A photosensitive resin laminate having a three-layer structure in which a protective film (cover film) is laminated is formed on the surface.

  The support film is not particularly limited as long as it is transparent and flexible, and examples thereof include a polyester film such as a polyethylene terephthalate (PET) film, an oriented polypropylene (OPP) film, and the like. A PET film is preferred.

  The protective film is used for the purpose of preventing transfer of the photosensitive resin composition layer having adhesiveness to the support film when the photosensitive film which is a photosensitive resin laminate is used in a roll shape. For example, a polyethylene (PE) film, a PET film, a polypropylene film (OPP), a polytetrafluoroethylene (PTFE) film, a polyvinyl alcohol film, a nylon film and the like can be mentioned, and a PE film is preferable. Furthermore, it is preferable to use a protective film having an average roughness (Ra) of 1.0 or more on the photosensitive resin composition layer lamination surface side. Usually, the upper limit is Ra = 3.0. That is, by using a material having such a surface average roughness (Ra), the uneven surface as the roughness surface is transferred to the photosensitive resin composition layer (resist). When laminating the resin laminate, the protective film is peeled off, the transferred uneven surface is brought into contact with the conductor circuit surface, and lamination is performed using a vacuum laminator. This is preferable because the following ability is good. When the surface average roughness (Ra) is less than 1.0, there is a tendency that transfer of the uneven surface to the resist becomes insufficient. In addition, the said surface average roughness (Ra) is an average height which remove | divided the area of the roughness curve by the measurement length, as shown by JIS-B-0601.

  The photosensitive resin laminate of the present invention can be produced, for example, as follows. That is, the photosensitive resin composition layer is formed by uniformly coating the photosensitive resin composition of the present invention on one surface of the support film and then drying. Next, a support film is laminated on the other side of the photosensitive resin composition layer by pressurizing and laminating a protective film on one side of the photosensitive resin composition layer, and a protective film on the other side of the photosensitive resin composition layer. A photosensitive resin laminate having a three-layer structure in which each is laminated can be produced.

  In the photosensitive resin laminate of the present invention, the thickness of the photosensitive resin composition layer varies depending on the thickness of the copper wiring, but is preferably 80 μm or less, particularly preferably 20 to 60 μm. That is, if the thickness of the photosensitive resin composition layer exceeds 80 μm, the curability of the lower part of the resist is poor during pattern exposure, resulting in poor adhesion or difficulty in obtaining sufficient resolution.

  The thickness of the support film is preferably 15 to 21 μm. That is, if it is less than 15 μm, the resistance of the photosensitive resin laminate itself is inferior and tends to be easily broken when the support film is peeled off. Conversely, if it exceeds 21 μm, the support film becomes hard, This is because the photosensitive resin composition layer tends to be inferior in followability to the circuit, which is not preferable. And the thickness of the said protective film is 10-50 micrometers normally, Preferably it is 18-35 micrometers.

  The photosensitive resin laminate of the present invention is useful as, for example, a flexible printed wiring board (FPC) as well as a wiring board cover lay and solder resist using a rigid substrate. Etc. Moreover, it can also be used as an ink applied directly on a circuit etc. without using a photosensitive resin laminate.

  The manufacturing method of the flexible printed wiring board using the photosensitive resin laminated body of this invention is demonstrated below.

〔laminate〕
In order to form an image with the photosensitive laminate, the protective film is peeled off from the photosensitive resin composition layer, and then the surface of the photosensitive resin composition layer is formed on the wiring surface of the substrate on which a conductor circuit such as FPC is formed. Laminate together. At this time, if a vacuum laminator is used, the followability to the conductor circuit becomes very high.

〔exposure〕
Next, the pattern mask is directly contacted (adhered) on the support film on the opposite side of the photosensitive resin composition layer and exposed. In the case of proximity exposure and projection exposure, the pattern mask is exposed in a non-contact state. Furthermore, direct imaging (direct exposure) using a laser may be performed without using a pattern mask. The exposure is usually performed by ultraviolet (UV) irradiation, and as a light source at that time, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, an argon laser, or the like is used.

〔developing〕
After the exposure, the support film on the photosensitive resin composition layer is peeled off, and the unexposed portion (uncured portion) is dissolved and dispersed by development. When the photosensitive resin composition is a dilute alkali development type, a dilute aqueous solution having an alkali concentration of about 0.3 to 2% by weight such as sodium carbonate or potassium carbonate is used as the developer. In the development, a method of spraying at a uniform pressure is preferable from the viewpoint of resolution and adhesion stability. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed. And after development, it is sufficiently washed with water and dried.

[UV (ultraviolet) cure]
In order to enhance properties such as surface curability, solder heat resistance, and chemical resistance, it is effective to perform UV curing (post-exposure) after sufficiently drying after development. UV cure is usually used at 0.5 to ¹⁰ J / cm ² . Thereby, the reaction of the remaining (meth) acrylic monomer component (B) having the ethylenically unsaturated group and the deactivation of the photopolymerization initiator (C) are performed.

[Heat cure]
In order to further enhance characteristics such as surface curability, solder heat resistance, and chemical resistance, a further crosslinking reaction step is performed. In the cross-linking reaction step that becomes the thermal cure, holding at 135 to 175 ° C. for 20 to 120 minutes is usually performed.

  The FPC in which the coverlay is formed in this manner is then mounted on various small electronic devices such as a mobile phone and a digital camera after components are mounted by soldering or the like.

  Next, examples will be described together with comparative examples.

  First, the following materials were prepared.

[Carboxyl group-containing polymer (A1)]
(A1-a)
Carboxyl group-containing polymer polymerized at a ratio of methyl methacrylate / n-butyl methacrylate / styrene / methacrylic acid = 45/15/15/25 (weight ratio) (weight average molecular weight Mw = 168,000, acid value 163 mgKOH / g ). The weight average molecular weight Mw is a value obtained by measuring a THF (tetrahydrofuran) solution of a dry polymer on a polystyrene basis using a GPC (gel permeation chromatography) apparatus.

[Carboxyl group-containing functional polymer (A2)]
(A2-a)
45% of carboxyl group-containing polymer (weight average molecular weight Mw = 16,800, acid value 345 mgKOH / g) obtained by polymerization at a ratio of methyl methacrylate / n-butyl methacrylate / methacrylic acid = 20/27/53 (weight ratio) In the propylene glycol monomethyl ether solution, an alicyclic epoxy group-containing unsaturated compound represented by the following general formula (2) [In the formula (2), R ₁ is hydrogen and R ₂ is —CH ₂ O—. ] Is reacted with 68 mol% of the carboxyl group in the carboxyl group-containing polymer (carboxyl group-containing functional polymer (weight average molecular weight Mw = 28,000, acid value 63 mgKOH / g, ethylenically unsaturated group). Amount 2.4 mmol / g).

(A2-b)
Isophorone diisocyanate and a compound represented by the following structural formula (b) [In the formula (b), R ₁ is hydrogen, R ₂ is —CH ₂ CH ₂ O—, and R ₃ is —CH ₂ CH ₂ O—. is there. ] 560 parts by weight (molecular weight 697) (hereinafter abbreviated as “parts”) of methyl methacrylate / n-butyl methacrylate / styrene / 2-hydroxyethyl methacrylate / methacrylic acid = 25/20/10/20 / 880 parts of a methyl ethyl ketone solution (solid content 50%) of a carboxyl group-containing polymer (weight average molecular weight Mw = 12,000, acid value 163 mg KOH / g) copolymerized at a ratio of 25 (weight ratio) was mixed with dibutyl. Carboxyl group-containing functional polymer obtained by adding 0.2 part of tin laurate and 0.2 part of hydroquinone monomethyl ether (weight average molecular weight Mw = 27,000, acid value 64 mgKOH / g, Saturated group amount 2.4 mmol / g).

(A2-c)
Carboxyl group-containing polymer (weight) obtained by copolymerizing 690 parts of equimolar reaction product of isophorone diisocyanate and diethylene glycol monomethacrylate with a ratio of methyl methacrylate / 2-hydroxyethyl methacrylate / methacrylic acid = 50/70/25 (weight ratio). 620 parts of methyl ethyl ketone solution (solid content 50%) having an average molecular weight Mw = 10,000 and an acid value of 163 mg KOH / g) was mixed, and 0.2 part of dibutyltin laurate and 0.2 part of hydroquinone monomethyl ether were added. Carboxyl group-containing functional polymer obtained by reaction (weight average molecular weight Mw = 32,000, acid value 46 mgKOH / g, ethylenically unsaturated group amount 1.8 mmol / g).

[(Meth) acrylic monomer (B)]
(B1-a)
Urethane methacrylate compound represented by the general formula (1) [in the formula (1), R = —CH ₃ , X = —CH ₂ CH ₂ O—, Y = —CH ₂ CH (CH ₃ ) O—, Z =-(CH ₂ ) _6- , k = 15, m = 6, n = 4]

(B2-a)
Epoxy (meth) acrylate containing 2 or more OH groups in one molecule ("Ebecryl 648" manufactured by Daicel UCB)

(B-3)
Ethylene oxide modified bisphenol A diacrylate (ethoxy group number 10)

(B-4)
Trimethylolpropane tripropoxytriacrylate

[Photopolymerization initiator (C)]
(C-1)
2-Methyl-1- [4- (methylthio) phenyl] -2-morifornopropan-1-one (Ciba, “Irgacure907”)

(C-2)
9-phenylacridine

(C-3)
2,4-diethylthioxanthone

[Amino resin (D)
"Resimene 735" made by UCB

[Phosphorus compound (E)]
(E-1)
Bisphenol A bis (dicresyl phosphate)

(E-2)
Three-membered ring composition of diphenoxyphosphazene

[Other additives]
(F-1)
Phthalocyanine blue pigment (F-2)
"Modaflow" manufactured by Surface Specialties
(F-3)
Fumed silica

[Examples 1 to 9, Comparative Examples 1 to 4]
The components shown in Tables 1 and 2 below were dissolved in a solvent (methyl ethyl ketone: isopropanol = 75: 25 [weight ratio]) in the proportions shown in the same table to prepare a photosensitive resin composition solution having a concentration of 55% by weight. did. Next, this photosensitive resin composition solution was uniformly coated on a 19 μm-thick PET film (support film) using an applicator, allowed to stand at room temperature for 1 minute and 30 seconds, and then in an oven at 130 ° C. for 3 minutes. It dried and formed the photosensitive resin composition layer of thickness 40 micrometers. Next, a PE film having a satin pattern formed with a thickness of 30 μm and a surface average roughness Ra = 1.51 [Ra is 10.0 mm long in the transverse direction (TD) direction of the film roll, and the tip of the contact is 2 μm R, measured. The value when measured at a load of 0.07 gf] was laminated at 30 ° C. and 0.2 MPa so that the photosensitive resin composition layer and the satin pattern forming surface were in contact with each other, and the thickness was 40 μm. A photosensitive resin laminate having a resin composition layer was produced.

  Using the photosensitive resin laminates of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following evaluation method. These results are shown in Tables 3 to 4 below.

〔sensitivity〕
The protective film (polyethylene film) of the photosensitive resin laminate is peeled off, and this is a copper foil of a copper-clad polyimide film for FPC (size 150 mm × 150 mm) obtained by laminating a 18 μm thick copper foil to a 25 μm thick polyimide film. The photosensitive resin composition layer of the photosensitive resin laminate is placed on the surface so as to be opposed to each other, and is temporarily attached to a vacuum using a diaphragm type vacuum laminator (Nichigo Morton, “V-130”). Lamination was performed under the conditions of a time of 30 seconds, a platen temperature of 55 ° C., a vacuum degree of 95 Pa, and a slap down of 8 seconds. This laminated product was allowed to stand at 20 ° C. for 2 hours, and a 21-step tablet made by Stouffer was in close contact with the PET film, exposed to a 2 kW mercury short arc lamp (parallel light), and then heated to 30 ° C. Spray development (spray pressure 0.15 MPa) was performed for 2 times the minimum development time with a 1 wt% Na ₂ CO ₃ aqueous solution, and the mixture was washed with water and dried. And the exposure amount when the numerical value of the step tablet in which the metal part has come out is 9 (9 steps) was displayed as sensitivity.

[Resolution]
In place of the 21-step tablet made by Stouffer when used in the above sensitivity measurement, the same operation was performed except that a pattern mask (silver salt-PET film) of line / space = 20 μm / 20 μm to 120 μm / 120 μm was used. Then, the above-described 2 kW ultra-high pressure mercury short arc lamp (parallel light) was irradiated with an exposure amount equivalent to 9 steps of a 21-step tablet made by Stouffer and developed. At this time, the value of the minimum line width indicating the resolution (the value of the minimum width between the cured lines formed by development) was displayed as the resolution.

[Developability]
A copper substrate (FR-4, thickness 1.6 mm) was prepared, the copper foil surface was buffed (after # 600, # 1000), washed with water, and then washed with 10% sulfuric acid at room temperature (25 ° C.). It was immersed for a minute, washed with water, dried, and left at room temperature for 24 hours. In the same manner as in the sensitivity measurement, the photosensitive resin composition layer having a thickness of 40 μm was formed on the copper substrate under the same conditions using a diaphragm vacuum laminator (Nichigo Morton, “V-130”). The photosensitive resin laminated body which has was laminated | stacked. The photosensitive resin laminate having the photosensitive resin composition layer having a thickness of 40 μm used here was 100 mm × 100 mm in size. After being left unexposed at 20 ° C. for 20 minutes, it was spray-developed with a 1 wt% Na 2 CO 3 aqueous solution at 30 ° C. for twice the minimum development time (spray pressure 0.15 MPa), washed with water and dried. After that, it is immersed again in water at 25 ° C., leaned on the rack at an angle of about 85 °, and the degree of water repelling on the surface of the substrate leaning on the rack is measured with a stopwatch. Was evaluated. That is, the degree of development residue (organic residue) on the copper substrate was determined by the water repellency test as follows.
A: Does not repel water for 15 seconds or longer (good developability).
○ ... Repels water in 10 seconds or more and less than 15 seconds.
X: Water is repelled in less than 10 seconds (there is an organic residue).

[Flexibility]
As in the case of the above sensitivity measurement, a photosensitive vacuum resin composition having a thickness of 40 μm on both sides of a polyimide film having a thickness of 25 mm under the same conditions using a diaphragm-type vacuum laminator (manufactured by Nichigo-Morton, “V-130”). A photosensitive resin laminate having layers was bonded and laminated. Then, the above 2 kW ultra-high pressure mercury short arc lamp (parallel light) was irradiated on both sides with an exposure amount equivalent to 9 steps of a 21-step tablet made by Stouffer, and UV cure 3 J / cm ² (made by International Light, “IL -Measurement value at −390A ”, followed by heat curing at 150 ° C. for 60 minutes to prepare a cured film. And the same location of this cured film was operated as a mountain fold to a valley fold to a mountain fold (folding radius 0 °), and the flexibility was evaluated as follows. The bending was performed in a room at 23 ° C. × 50% RH.
A: No cracking was observed even after 10 or more operations.
○: Cracked in 6 to 9 operations.
Δ: Cracked in 2 to 5 operations.
X: Cracked in one operation.

[Solder heat resistance]
Using a copper-clad polyimide film having a copper thickness of 18 μm and forming a copper wiring of IPC-B-25A (IPC standard), a photosensitive resin laminate having the photosensitive resin composition layer having a thickness of 40 μm, In the same manner as in the sensitivity measurement, a diaphragm-type vacuum laminating machine (manufactured by Nichigo-Morton, “V-130”) was used and bonded and laminated under the same conditions. Next, using a pattern mask to which the D pattern terminals of this circuit can be soldered, the above 2 kW ultra-high pressure mercury short arc lamp (parallel light) is irradiated with an exposure amount equivalent to 9 steps of a 21-step tablet made by Stouffer. Then, development and drying were performed in the same manner as the sensitivity measurement. Subsequently, 3J / cm ² UV curing was performed using a transport UV exposure machine “model UVCS 923” (measured with IL-390A, manufactured by International Light). The substrate temperature at this time was 120 ° C. Then, the flexible printed wiring board (FPC) in which the coverlay was formed was produced by heat-curing for 60 minutes at 150 degreeC.

Next, flux ULF-500VS manufactured by Tamura Kaken Co., Ltd. was applied to the surface of the FPC, followed by drying at 100 ° C. for 1 minute, and soldering at 260 ° C. for 10 seconds. When this flux application to soldering operation is repeated a total of three times, the coverlay cracking state, the D pattern solder flaking state, and the swollenness state are visually observed and combined to ensure solder heat resistance. Evaluation was performed as follows.
◎ ... No cracks, solder flaking, or blistering was observed in all three times.
○: There was no problem in both cases, but some solder peeling was confirmed in the third time.
Δ: Slight soldering was confirmed at the second time, and swelling occurred at the third time.
X: The soldering operation could not be already performed in the first time.

[Solvent resistance]
FPC obtained by going through the same process as the solder heat resistance was put into an isopropyl alcohol boiling solution and immersed for 2 minutes. Then, the occurrence of floating and peeling from the substrate was visually observed, and the solvent resistance was evaluated as follows.
A: Neither floating nor peeling occurred.
X: Floating or peeling occurred.

[Alkali resistance]
FPC obtained by going through the same process as the solder heat resistance was put into a 10% NaOH aqueous solution at 40 ° C. and stirred for 10 minutes. Then, the state of occurrence of floating and peeling from the substrate was visually observed, and the alkali resistance was evaluated as follows.
◎ ・ ・ ・ Neither floating nor peeling occurred, and the surface was glossy.
○: No floating or peeling occurred, but the surface was not very glossy.
X: Floating or peeling occurred.

[Electrical insulation]
An IPC-SM-840C3.9.1 (IPC standard) electrical migration test was performed using the FPC obtained through the same process as the solder heat resistance. That is, using the D pattern, the resistance after 168 hours was examined at 85 ° C. × 90% RH for 168 hours, 10 VDC bias potential, and 45-100 VDC test potential, and the electrical insulation was evaluated as follows. According to the standard, 2 MΩ or more is accepted.
◎ ... exceeded 200 MΩ.
O: 2 to 200 MΩ.
X: Less than 2 MΩ.

[Trackability to circuit]
A base material on which a copper wiring of IPC-B-25A (IPC standard) was formed using a copper-clad polyimide film having a copper thickness of 35 μm was prepared in advance. The copper wiring side is temporarily attached using a photosensitive resin laminate having a thickness of 25 μm (a support film having a thickness of 19 μm and a photosensitive resin composition layer having a thickness of 25 μm), and the temperature during vacuum lamination is changed (50 ° C., Except for 55 degreeC and 65 degreeC, the photosensitive resin laminated body of 25 micrometers in thickness was bonded and laminated | stacked using the vacuum laminating machine (the Nichigo-Morton company make, V-130) similarly to the time of the said sensitivity measurement. And it exposed at 150 mJ / cm < ² >, the substrate surface was observed with the microscope, and the followability to a circuit was evaluated as follows.
A: Following completely at 50 ° C., there was no space between the photosensitive resin composition layer and the circuit.

○: Although it did not follow completely at 50 ° C., it followed completely at 55 ° C. and there was no space between the photosensitive resin composition layer and the circuit.
Δ: Although it did not follow completely at 55 ° C., it followed completely at 65 ° C., and there was no space between the photosensitive resin composition layer and the circuit.
X: It did not follow completely even at 65 ° C.

〔Flame retardance〕
FR-4 [0.3 mm thick copper clad laminate (CEL475SD manufactured by Shin-Kobe Electric Machinery Co., Ltd.) was etched in advance) as a base material. Next, instead of the photosensitive resin composition layer having a thickness of 40 μm, a photosensitive resin laminate in which a photosensitive resin composition layer having a thickness of 55 μm is formed is temporarily attached to both surfaces of the substrate, and a diaphragm type vacuum laminating machine ( Using “V-130” manufactured by Nichigo-Morton Co., Ltd., lamination was performed under the conditions of a decompression time of 30 seconds, a platen temperature of 55 ° C., a vacuum degree of 95 Pa, and a slap down of 8 seconds. Next, both surfaces were exposed at 150 mJ / cm ² (ORC UV-351 integrating light meter). Thereafter, the inside of the developing tank of 1 wt% Na ₂ CO ₃ aqueous solution at 30 ° C. was passed through at a pass time of 0.15 MPa for 45 seconds, and sufficiently washed and dried. Thereafter, using model UVCS923, double-sided UV curing was performed at 3 J / cm ² (measured with “IL-390A” manufactured by International Light), and then heat curing (150 ° C. × 60 minutes) was performed. A sample product was prepared.

  The above sample product was cut into a length of 125 ± 5 mm and a width of 13.0 mm ± 0.5 mm, and conformed to UL-94, a flame retardant test standard for polymer materials of Underwriters Laboratories Inc. (hereinafter referred to as “UL”) in the United States. Therefore, a vertical flammability test was performed. In accordance with this standard, the flame retardancy evaluation was expressed as V-0, V-1, V-2, and NOT-V from those having good flame retardancy.

  From the above results, the example products have high sensitivity and high resolution, and all of developability, flexibility, solder heat resistance, solvent resistance, alkali resistance, electrical insulation, and followability to conductor circuits. Excellent results were obtained. Furthermore, since the phosphorus compound (E) is contained, it is understood that the flame retardancy is also excellent.

On the other hand, the product of Comparative Example 1 does not use the carboxyl group-containing functional polymer (A2), and therefore the evaluation results are inferior in resolution, poor in developability, and insufficient in the followability to the conductor circuit. It was. Moreover, since the product of Comparative Example 2 did not use the carboxyl group-containing polymer (A1), the evaluation results were insufficient with respect to flexibility, solder heat resistance, solvent resistance, and alkali resistance. And since the product of Comparative Example 3 did not use the (meth) acrylic monomer (B), it was inferior in sensitivity and resolution, and inferior in solder heat resistance, solvent resistance and alkali resistance. Furthermore, since the product of Comparative Example 4 did not use the amino resin (D), it was inferior in solder heat resistance and solvent resistance, and further in alkali resistance.

Claims (8)

A photosensitive resin composition comprising the following (A) to (D):
(A) A polymer component mainly composed of the following (A1) and (A2).
(A1) A carboxyl group-containing (meth) acrylic polymer having a weight average molecular weight of 100,000 to 250,000 and an acid value of 50 to 250 mgKOH / g.
(A2) A carboxyl group having a weight average molecular weight of 5,000 to 50,000, an acid value of 40 to 160 mgKOH / g, and containing 0.3 to 3.5 mmol / g of ethylenically unsaturated groups in the side chain Containing (meth) acrylic functional polymer.
(B) A (meth) acrylic monomer component having an ethylenically unsaturated group.
(C) Photopolymerization initiator.
(D) Amino resin. The photosensitive resin according to claim 1, wherein the (meth) acrylic monomer component (B) having an ethylenically unsaturated group contains a urethane (meth) acrylate compound (B1) represented by the following general formula (1). Composition.

  The photosensitive resin composition of Claim 1 or 2 with which content of a polymer component (A) is set to the range of 25 to 45 weight% of the whole photosensitive resin composition except a solvent. The photosensitive resin composition as described in any one of Claims 1-3 which contains the following (E) in addition to (A)-(D).
(E) A phosphorus compound containing at least four phenoxy groups in one molecule.   The photosensitive resin composition according to any one of claims 1 to 4, wherein the photosensitive resin composition is a photosensitive resin composition for a solder resist.   A photosensitive resin laminate in which a support film is laminated on one side of a photosensitive resin composition layer, and a protective film is laminated on the other side of the photosensitive resin composition layer, the photosensitive resin composition layer Is formed using the photosensitive resin composition as described in any one of Claims 1-5, The photosensitive resin laminated body characterized by the above-mentioned.   The photosensitive resin laminate according to claim 6, wherein the surface average roughness (Ra) of the protective film on the photosensitive resin composition layer lamination surface side is 1.0 or more. The photosensitive resin laminate according to claim 6 or 7, wherein the photosensitive resin laminate is a solder resist laminate.