JPH0990628A - Photopolymerizable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photopolymerizable resin compsn. suitable for a dry film photoresist having superior performance. SOLUTION: This photopolymerizable compsn. contains 20-90wt.% resin (a) for a binder, 5-60wt.% photopolymerizable unsatd. compd. (b) and 0.01-30wt.% photopolymn. initiator (c) as essential components. The resin (a) is a linear copolymer (A) having a carboxyl group content of 100-600 (expressed in terms of the equiv. of an acid) and a wt. average mol.wt. of 100,000-500,000 or a mixture prepd. by mixing the copolymer (A) with a linear copolymer (B) having a carboxyl group content of 100-600 (expressed in terms of the equiv. of an acid), a wt. average mol.wt. of 30,000-90,000 and using a vinyl compd. having a phenyl group as one of the copolymerized components so as to regulate the wt. ratio of A:B to 90:10 to 10:90.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a photopolymerizable composition and a photopolymerizable laminate, and more particularly to an alkali-developable photopolymerizable composition and a photopolymerizable laminate suitable for producing a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, a so-called dry film resist (hereinafter referred to as DFR) composed of a support layer and a photopolymerizable layer has been used as a resist for producing a printed circuit. DF
R is generally prepared by laminating a photopolymerizable composition on a supporting film, and in many cases, laminating a protective film on the composition. Such a photopolymerizable layer is generally of an alkali developing type using a weak alkaline aqueous solution as a developing solution.

In order to produce a printed circuit board using DFR, the protective film is first peeled off, and then the DFR is laminated on a substrate for producing a permanent circuit such as a copper clad laminate using a laminator or the like to form a wiring pattern mask film. And the like to expose. Next, if necessary, the supporting film is peeled off, and the photopolymerizable composition in the unexposed portion is dissolved or dispersed by a developing solution to form a cured resist image on the substrate. Using the formed resist image as a mask, the metal surface of the substrate is subjected to etching or plating, and then the resist image is peeled off using an alkaline aqueous solution stronger than the developing solution to form a printed wiring board or the like. Especially recently, the through-holes (through-holes) are covered with a cured film because of the simplicity of the process.
A so-called tenting method of etching thereafter is often used. Cupric chloride, ferric chloride, copper ammonia complex solution, etc. are used for etching, but when the cured film is broken by the pressure of spray etc. in the process of development and etching, the internal conductor is removed and the wire breaks. Will lead to defects. Therefore, the cured film is required to have strong film strength and flexibility. On the other hand, since the DFR is stored in a roll having a three-layer structure, the photopolymerizable layer protrudes from the end surface during storage,
A so-called cold flow phenomenon may occur, but this phenomenon is not preferable in terms of handling.

Further, if the unexposed photopolymerizable layer in the DFR is hard, the adhesion is poor when it is laminated on the substrate, and the photopolymerizable layer can fill the irregularities on the irregular substrate surface. There may be a space between the photopolymerizable layer and the substrate. When such a space is created, the etching liquid permeates the substrate, resulting in defects such as disconnection and chipping.

The photopolymerizable layer of DFR, which is widely used at present, has (1) an unsaturated compound having at least one ethylenic group and capable of forming a polymer by a photopolymerization initiator,
It is composed of a composition comprising (2) a thermoplastic organic polymer binder, (3) a photopolymerization initiator, and (4) other additives. (Japanese Patent Publication No. 50-9177, Japanese Patent Publication No. 5)
7-21697). As the unsaturated compound, acrylic acid and methacrylic acid esters of aliphatic polyhydric alcohols are most common, and at least two unsaturated compounds such as trimethylolpropane triacrylate pentaerythritol triacrylate and polyethylene glycol diacrylate. Those having a group are known.

[0006]

In order to improve the cold flow, it suffices to relatively increase the blending ratio of the binder in the photopolymerizable layer, and then the followability of the photopolymerizable layer to the substrate. Of the tenting film, and the flexibility and strength of the tenting film are decreased. Further, in order to improve the tenting film strength and the followability of the photopolymerizable layer to the substrate, the compounding ratio of the binder in the photopolymerizable layer may be relatively decreased, which causes deterioration of cold flow, There is a problem that the peeling time increases. Therefore, a photopolymerizable composition that satisfies these properties at the same time has been desired.

[0007]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, a cured resist was obtained when the photopolymerizable composition using the linear polymer of the following (a) was used for DFR. It was found that such properties as good flexibility, good tent film strength, good cold flow property and good followability of the photopolymerizable layer to the substrate, and storage at room temperature for 6 months or more can be obtained. The present invention has been completed.

That is, according to the present invention, (a) a binder resin comprising a linear copolymer A having a carboxyl group content of 100 to 600 in acid equivalent and a weight average molecular weight of 100,000 to 500,000, 20 to 90% by weight, (b) a photopolymerizable unsaturated compound, 5 to 60% by weight, (c) a photopolymerization initiator, and 0.01 to 30% by weight. Provide things.

The present invention also provides (a) a linear copolymer A having a carboxyl group content of 100 to 600 in acid equivalent and a weight average molecular weight of 100,000 to 500,000, and a carboxyl group content. Is a linear copolymer B having an acid equivalent of 100 to 600 and a vinyl compound having a phenyl group with a weight average molecular weight of 30,000 to 90,000 as one of the copolymerization components.
20 to 90% by weight of a binder resin in which A / B is mixed in a weight ratio of 90/10 to 10/90.
(B) a photopolymerizable unsaturated compound, 5 to 60% by weight,
(C) A photopolymerization composition containing a photopolymerization initiator in an amount of 0.01 to 30% by weight is also provided.

The amount of carboxyl groups contained in the linear copolymer A constituting the binder resin (a) used in the present invention must be 100 to 600 in terms of acid equivalent, and 300 to 4
00 is preferable. The molecular weight of the linear copolymer A is 10 to
It is necessary to be 500,000, and more preferably 200,000 to 400,000. If the molecular weight of the linear copolymer A exceeds 500,000, the developability will decrease, and if it is less than 100,000, the tenting film strength and the followability of the photopolymerizable layer to the substrate will deteriorate.

Here, the acid equivalent means the weight of the polymer having 1 equivalent of a carboxyl group therein. The measurement of the acid equivalent is performed by a potentiometric titration method. The molecular weight is determined as a weight average molecular weight (converted to polystyrene) by gel permeation chromatography (GPC). Further, the carboxyl group in the linear copolymer is necessary for giving the DFR developability and releasability to an aqueous alkaline solution. If the acid equivalent is less than 100, the compatibility with the coating solvent or other composition, for example, the monomer is lowered, and 60
When it exceeds 0, the developability and the peeling property are deteriorated.

The linear copolymer A can be obtained by copolymerizing one or more of the following two types of monomers. The first monomer is a carboxylic acid or acid anhydride having one polymerizable unsaturated group in the molecule.
For example, (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester and the like. The second monomer is non-acidic, has one polymerizable unsaturated group in the molecule, and has various properties such as developability of the photopolymerizable layer, resistance in etching and plating steps, and flexibility of the cured film. Selected to retain properties. For example, methyl (meth) acrylate, ethyl (meth) acrylate,
There are alkyl (meth) acrylates such as butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. Also, a vinyl compound having a phenyl group (for example, styrene) can be used.

The linear copolymer A, even if used alone, has a following property,
Although the adhesiveness is good, the combined use with the linear copolymer B enables a more rapid development process. When used in combination, A / B (weight ratio) is 90/10 to 10/90.
It is. The amount of the carboxyl group contained in the linear copolymer B used in the present invention needs to be 100 to 600 in terms of acid equivalent, and preferably 300 to 400. In addition, linear copolymer B
The molecular weight of is required to be 30,000 to 90,000. Linear copolymer B
If the molecular weight exceeds 90,000, the developability will decrease, and if it is less than 30,000, the tenting film strength and cold flow properties will deteriorate.

Here, the acid equivalent means the weight of a polymer having 1 equivalent of a carboxyl group therein. The measurement of the acid equivalent is performed by a potentiometric titration method. The molecular weight is determined as a weight average molecular weight (converted to polystyrene) by gel permeation chromatography (GPC). Further, the carboxyl group in the linear copolymer is necessary for giving the DFR developability and releasability to an aqueous alkaline solution. If the acid equivalent is less than 100, the compatibility with the coating solvent or other composition, for example, the monomer is lowered, and 60
When it exceeds 0, the developability and the peeling property are deteriorated.

The linear copolymer B, like A, can be obtained by copolymerizing a monomer selected from the above monomers.
A vinyl compound having a phenyl group is an essential component. Styrene is preferred as the vinyl compound. The amount of the binder resin (a) contained in the photopolymerizable composition of the present invention is in the range of 20 to 90% by weight, preferably 30 to 70%.
% By weight. When the amount of the binder resin (a) is less than 20% by weight or more than 90% by weight, the cured image formed by exposure has sufficient resist characteristics, for example, sufficient resistance in tenting, etching and various plating steps. I don't have it.

Examples of the photopolymerization initiator (c) that can be used in the present invention include known photopolymerization initiators that are activated by various actinic rays such as ultraviolet rays to initiate polymerization. Examples of such a photopolymerization initiator include 2
-Ethylanthraquinone, octaethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 1 Quinones such as 4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl 1,4-naphthoquinone, 2,3-dimethylanthraquinone, 3-chloro-2-methylanthraquinone, benzophenone, Michler's ketone [4,4'-bis (dimethylamino ) Benzophenone], 4,4′-bis (diethylamino) benzophenone and other aromatic ketones, benzoin, benzoin ethyl ether, benzoin phenyl ether, methylbenzoin, ethylbenzo Benzoin ethers such as down, benzyl dimethyl ketal, benzyl diethyl ketal, 2-(o over-chlorophenyl) over 4,5 over diphenyl imidazolylmethyl dimers such biimidazole compounds of the combination of thioxanthones and alkylamino benzoic acid,
For example, a combination of ethylthioxanthone and ethyl dimethylaminobenzoate, 2-chlorothioxanthone and ethyl dimethylaminobenzoate, a combination of isopropylthioxanthone and ethyl dimethylaminobenzoate, and 2- (ο
-Chlorophenyl) -4,5-diphenylimidazolyl dimer in combination with Michler's ketone, acridines such as 9-phenylacridine, 1-phenyl-1,2
There are oxime esters such as -propanedione-2-o-benzoyl oxime, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime and the like. Preferred examples of these photopolymerization initiators include thioxanthones such as diethylthioxanthone and chlorothioxanthone, dialkylaminobenzoic acid esters such as ethyl dimethylaminobenzoate, benzophenone, and 4,
4'-bis (dimethylamino) benzophenone, 4,
Mention may be made of 4′-bis (diethylamino) benzophenone, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, and combinations thereof.

As the photopolymerizable unsaturated compound (b) constituting the photopolymerizable composition of the present invention, a photopolymerizable monomer having at least two terminal ethylene groups is preferably used. Examples thereof include 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polyoxyethylene poly. Polyoxyalkylene glycol di (meth) acrylates such as oxypropylene glycol di (meth) acrylate, 2-di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate , Polyoxypropyltrimethylolpropane tri (meth) acrylate, polyoxyethyltrimethylolpropane triacrylate, dipentaerythritol penta (meth) acrylate, Trimethylolpropane triglycidyl ether tri (meth) acrylate,
Examples include bisphenol A diglycidyl ether di (meth) acrylate, 2,2-bis (4-methacryloxypentaethoxyphenyl) propane, and a polyfunctional (meth) acrylate containing a urethane group.

Preferred examples include those represented by the following general formulas (I) and (II). These may be used alone or in combination with other polyfunctional monomers or monofunctional monomers. A system in which the monomers of the general formulas (I) and (II) are used in combination is also desirable, and by using these monomers, the tenting film which is flexible and has good followability to the substrate of the photopolymerizable layer Is obtained.

[0019]

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[0020]

Embedded image

The compound represented by the general formula (I) includes
For example, a diisocyanate compound such as hexamethylene diisocyanate, tolylene diisocyanate or 2,2,4-trimethylhexamethylene diisocyanate, and a compound having a hydroxyl group and a (meth) acryl group in one molecule (for example, 2-hydroxypropyl acrylate) , Oligopropylene glycol monomethacrylate and the like). These can be synthesized by a known method.

In the compound represented by the general formula (II), when n3, n4 and n5 are smaller than 3, the boiling point of the compound is lowered, the odor of the resist becomes strong and the use becomes extremely difficult. Further, when n3, n4 and n5 exceed 20, the concentration of photoactive sites per unit weight becomes low, so that practical sensitivity cannot be obtained. The compound represented by the general formula (II) can be synthesized by a method in which a product obtained by reacting propylene oxide and ethylene oxide is esterified with acrylic acid or methacrylic acid in the presence of a suitable acid catalyst. .

These monomers may be used alone or in combination of two or more. The amount used is selected from the range of 5 to 60% by weight. When it is less than 5% by weight, the sensitivity and film strength are not sufficient, and when it exceeds 60% by weight, the photopolymerizable layer during storage when used for DFR. This is not preferable, because the protrusion of the notch becomes remarkable. The amount of the photopolymerization initiator contained in the photopolymerizable composition of the present invention is 0.01% by weight to 30% by weight, preferably 0.05% by weight to 10% by weight. If the amount of the photopolymerization initiator exceeds 30% by weight, the active absorption rate of the photopolymerizable composition becomes high, and when used as a photopolymerizable laminate, curing due to polymerization of the bottom portion of the photopolymerizable layer becomes insufficient. . If the amount of the photopolymerization initiator is less than 0.01% by weight, sufficient sensitivity cannot be obtained.

In order to improve the thermal stability and storage stability of the photopolymerizable composition of the present invention, it is preferable to add a radical polymerization inhibitor to the photopolymerizable composition. Examples of such a radical polymerization inhibitor include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol,
2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), nitrosophenylhydroxyamine aluminum salt, diphenylnitrosamine and the like.

The photopolymerizable composition of the present invention may contain coloring substances such as dyes and pigments. Examples of such coloring substances include fuchsin, phthalocyanine green, auramine base, chalcoxide green S, paramagenta, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, diamond green and the like. To be

Further, a color-forming dye which develops color upon irradiation with light may be contained in the photopolymerizable composition of the present invention. Examples of the color forming dye include a combination of a leuco dye or a fluorane dye and a halogen compound. Examples of the leuco dye include tris (4-dimethylamino-2-methylphenyl) methane [leuco crystal violet], tris (4-dimethylamino-2-methylphenyl) methane [leucomalachite green], and the like. On the other hand, as the halogen compound, amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl sulfone, carbon bromide, tris (2,3,3). -Dibromopropyl) phosphate, trichloroacetamide, amyl iodide, isobutyl iodide,
1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane, hexachloroethane, triazine compounds and the like can be mentioned.

Examples of the triazine compound include 2,4,6-tris (trichloromethyl) -s-triazine and 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine. Further, among such color-forming dyes, a combination of tribromomethylphenyl sulfone and a leuco dye or a combination of a triazine compound and a leuco dye is useful.

Further, a small amount of a glycidyl ether compound may be added to the photopolymerizable resin composition of the present invention as a thermal color-developing agent. Specific examples of such a thermal color development inhibitor include polypropylene glycol diglycidyl ether,
Glycerin diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol A-PO2 mol addition diglycidyl ether and the like can be mentioned.

If desired, the photopolymerizable composition of the present invention may contain additives such as a plasticizer. Examples of such additives include phthalic esters such as diethyl phthalate. In the case of a photopolymerizable resin laminate for DFR, a support layer supporting the photopolymerizable layer is laminated on the photopolymerizable layer containing the photopolymerizable resin composition. As the support layer, a transparent layer that transmits active light is desirable. As the support layer that transmits active light, a polyethylene terephthalate film, a polyvinyl alcohol film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyvinylidene chloride film, a vinylidene chloride copolymer film, a polymethyl methacrylate copolymer film , Polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films, cellulose derivative films, and the like. Moreover, these films can be stretched and used as needed. A thinner film is more advantageous in terms of image forming property and economical efficiency, but it is generally 10 to 30 μm in order to maintain strength.

If necessary, a protective layer is laminated on the surface opposite to the photopolymerizable layer laminated with the support layer. An important characteristic of the protective layer is that the protective layer has a sufficiently small adhesive force with the photopolymerizable layer and can be easily peeled off more easily than the supporting layer. Examples of such a protective layer include a polyethylene film and a polypropylene film. Further, as the protective layer, a film having excellent releasability disclosed in JP-A-59-202457 can be used.

Although the thickness of the photopolymerizable layer varies depending on the use, it is 5 to 100 μm, preferably 5 to 90 μm for making a printed circuit board, and the thinner the photopolymerizable layer, the higher the resolution. Further, as the photopolymerizable layer is thicker, the film strength is improved. The process of producing a printed circuit board using this photopolymerizable resin laminate can be performed by a known technique, but it will be briefly described below.

When there is a protective layer, the protective layer is first peeled off, and then the photopolymerizable layer is laminated on the metal surface of the printed circuit board substrate by thermocompression bonding using a laminator. The heating temperature at this time is generally 40 to 160 ° C. Next, if necessary, the support layer is peeled off, and image exposure is performed with actinic light through a mask film. Next, if there is a support film on the photopolymerizable layer, it is removed if necessary, and subsequently, the unexposed portion of the photopolymerizable layer is removed by development using an alkaline aqueous solution. As the alkaline aqueous solution, an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or the like is used. These alkaline aqueous solutions are selected according to the characteristics of the photopolymerizable layer, but generally 0.5% to 3% sodium carbonate aqueous solution is used. Next, a metal image pattern is formed by performing a known etching method or a plating method on the metal surface exposed by the development.
After that, the cured resist image is peeled off with an alkaline aqueous solution which is generally stronger than the alkaline aqueous solution used in the development. The alkaline aqueous solution for stripping is also not particularly limited, but an aqueous solution of 1% to 5% sodium hydroxide or potassium hydroxide is generally used. It is also possible to add a small amount of a water-soluble organic solvent to a developer or a stripper.

[0033]

【Example】

[0034]

Example 1 A compound having the composition shown in Table 1 (column of Example 1) was uniformly dissolved. Next, add this mixed solution to a thickness of 25 μm.
m polyethylene terephthalate film was uniformly applied using a bar coater and dried in a dryer at 95 ° C. for 4 minutes. At this time, the thickness of the photopolymerizable layer was 40 μm. A 35 μm polyethylene film was laminated on the surface of the photopolymerizable layer on which no polyethylene terephthalate film was laminated to obtain a laminated film. On the other hand, 35μ
m Wet buff roll polishing of the surface of a copper clad laminate laminated with rolled copper foil (manufactured by 3M, trade name Scotch Bright # 60)
Then, the photopolymerizable layer was laminated at 105 ° C. by using a hot roll laminator while peeling off the polyethylene film of the laminated film.

This laminate was irradiated with an ultrahigh pressure mercury lamp (HMW-201KB manufactured by Oak Co., Ltd.) through a mask film to expose the photopolymerizable layer at 80 mJ / cm ² . Then, after peeling off the polyethylene terephthalate support film, a 1% sodium carbonate aqueous solution at 30 ° C. was sprayed for about 90 seconds to dissolve and remove the unexposed portion, whereby a good cured image was obtained.

Further, the following evaluations were carried out on the laminates using the photopolymerizable composition of the present invention. (1) Cold Flow Property Test The laminate obtained in Example 1 was cut into 2.5 cm square pieces, sandwiched between iron plates having a diameter of 10 cm, and 40 ° C. for 5 minutes, 1
A load of 00 Kg was applied. The sample was taken out, and the width of the photopolymerizable layer that protruded was measured. The following rankings were used for evaluation.

◯: less than 300 μm, 23 in roll state
Can be stored at ℃ for 6 months or more without cold flow. Δ: 300 μm or more and less than 600 μm, can be stored under the same conditions for 1 month or more and less than 6 months without cold flow. ×: 600 μm or more and less than 1 month Can be stored without cold flow. (2) Measurement of minimum development time The photopolymerizable layer was removed by a hot roll laminator at 105 ° C. while peeling off the polyethylene film of the dry film resist from the copper clad laminate laminated with 35 μm rolled copper foil.
It was laminated with. Then, after peeling off the polyethylene terephthalate support film of this laminated body, 1 degreeC of 30 degreeC was carried out.
% Aqueous solution of sodium carbonate was sprayed, and the minimum time required for the unexposed photopolymerizable layer to dissolve was measured, and this time was defined as the minimum development time. The actual development was carried out for 1.5 times the minimum development time. (3) Follow-up evaluation test Laminate exposure-development-etching resist peeling was previously performed on a copper-clad laminate laminated with 70 μm rolled copper foil using a commercially available dry film resist to obtain a line width of 100, 110, 120. , 130, 140, 15
A 0 μm linear groove was formed. The depth of the groove was about 10 μm.

Using the grooved substrate thus prepared, the above laminate was laminated in the same manner as above. An image pattern was obtained by exposing and developing a line pattern (line width; 125 μm) that was perpendicular to the groove of the substrate through the laminate with a mask film. Furthermore, 5
A cupric chloride solution at 0 ° C. was sprayed for 120 seconds to etch the copper in the resist-free area. Finally 3 at 50 ℃
% Aqueous sodium hydroxide solution was sprayed for about 90 seconds to remove the cured resist. On the copper line thus produced, the number of locations where the grooved portion was not broken was counted, and the number was defined as x. On the other hand, the number of locations where etching was caused and disconnection was counted, the number was defined as y, the disconnection rate (%) was calculated by the following calculation formula, and ranked by the following method.

Breakage rate (%) = 100x / (x + y) ○; Breakage rate is less than 30% △; Breakage rate is 30% or more and less than 50% ×; Breakage rate is 50% or more (4) Flexibility and film strength test A copper-clad laminate having through holes with a diameter of 5 mm was laminated on both sides by the method described in Example 1, exposed and developed without using a pattern mask. Then, the cured film on one surface was removed, a piercing bar was set in a jig of a tensile tester, and the central portion of the film of the through hole was pressed at a speed of 10 mm / min with a load of 5 kg. As a result, the elongation of the cured film until the film was broken and the strength at that time were measured.

[0040]

Examples 2 to 6 and Comparative Examples 1 and 2 By the same method as in Example 1, photopolymerizable resin laminates having the compositions shown in Tables 1 and 2 were obtained, and cold flow test, followability test, and flexibility were obtained. And the film strength test was conducted. The results are shown in Tables 1 and 2. <Description of symbols> P-1: 70% by weight of methyl methacrylate,
Methyl ethyl ketone solution of terpolymer of 23% by weight methacrylic acid and 7% by weight butyl acrylate (solid content 3
2%, weight average molecular weight 85,000) P-2: 70% by weight of methyl methacrylate, 23% by weight of methacrylic acid, 7% by weight of butyl acrylate, methyl ethyl ketone solution of a terpolymer (solid concentration 24%, Weight average molecular weight 300,000) P-3: Methyl tylketone solution of terpolymer of methyl methacrylate 47% by weight, methacrylic acid 23% by weight, and styrene 30% by weight (solid content concentration 32%, weight average molecular weight 4. 50,000) P-4: Methyl tylketone solution of a terpolymer of methyl methacrylate 47% by weight, methacrylic acid 23% by weight, and styrene 30% by weight (solid content concentration 32%, weight average molecular weight 85,000). M-1: trimethylolpropane triacrylate M-2: hexamethylene diisocyanate and oligopropylene glycol monomethacrylate (NOF Corporation)
Reaction product with Blemmer PP1000) M-3: Dimethacrylate of glycol obtained by adding 3 mol of ethylene oxide on both ends on average to polypropylene glycol to which 8 mol of propylene oxide is added on average 3-4: Tetrapropylene glycol dimethacrylate M -5: Tetraethylene glycol diacrylate A-1: Benzophenone A-2: 4, 4'-bis (dimethylamino) benzophenone A-3: 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer B- 1: Malachite Green B-2: Leuco Crystal Violet B-3: Tribromomethylphenylsulfone

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

EFFECT OF THE INVENTION D using the photopolymerizable resin composition of the present invention
FR has a particularly low cold flow property during storage, good followability when laminated on a substrate, and further exhibits excellent performance in flexibility and film strength of a cured film after exposure,
It is useful as a DFR for making an alkali development type circuit board.

Claims (2)

[Claims] 1. (a) A binder resin comprising a linear copolymer A having a carboxyl group content of 100 to 600 in acid equivalent and a weight average molecular weight of 100,000 to 500,000.
20 to 90% by weight, (b) a photopolymerizable unsaturated compound,
5 to 60% by weight, (c) photopolymerization initiator, 0.01 to 30
A photopolymerizable composition, characterized in that the photopolymerizable composition comprises a weight percentage. 2. A linear copolymer A having a carboxyl group content of 100 to 600 in acid equivalent and a weight average molecular weight of 100,000 to 500,000, and a carboxyl group content in acid equivalent of (a). A linear copolymer B having a weight average molecular weight of 100 to 600 and a vinyl compound having a phenyl group having a weight average molecular weight of 30,000 to 90,000 as one of the copolymerization components has a weight ratio of A /
Resin for binder mixed so that B becomes 90/10 to 10/90, 20 to 90% by weight, (b) photopolymerizable unsaturated compound, 5 to 60% by weight, (c) photopolymerization initiator,
A photopolymerizable composition comprising 0.01 to 30% by weight.