JPH09255756A - Cross-linkable resin composition and method for curing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cross-linkable resin compsn. which can form a resist of which the surface after cross-linking can be roughened by treating with a solvent such as an acid or an alkali and to provide a method for cross-linking the same. SOLUTION: This compsn. is prepd. by compounding 30-60 pts.wt. ehtylenically unsatd. compd. (A) having at least two (meth)acryloyloxy groups in the molecule, 30-60 pts.wt. binder polymer (B) produced from 15-30wt.% α,β-unsatd. carboxylated monomer, 5-30wt.% hydroxylated monomer, and 40-80wt.% other copolymerizable monomers and having a wt. averate mol.wt. of 50,000-200,000, 10-30 pts.wt. binder polymer (C) produced from 5-30wt.% α,β- unsatd. carboxylated monomer and 70-95wt.% other copolymerizable monomers and having a wt. average mol.wt. of 10,000-50,000, 1-20 pts.wt. blocked polyisocyanate (D), and up to 10 pts.wt. (based on 100 pts.wt. sum of ingredients A, B, C, and D) photopolymn. initiator. A method for cross-linking the compsn. is also provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crosslinkable curable resin composition useful as a protective film, a structural material, particularly a solder resist used as an interlayer insulating film of a build-up type multilayer wiring printed circuit board.

[0002]

2. Description of the Related Art Conventionally, when a multilayer wiring printed circuit board is formed by stacking wiring layers in a multilayer structure by a build-up method, in order to improve the adhesion between the interlayer insulating film and the conductive circuit and the insulating film, the surface of the insulating layer is improved. There is known a method of roughening the surface to give an anchor effect. As one example, an organic solvent solution of a photosensitive resin mixed with an inorganic filler such as hydroxide, carbonate, or sulfate, which is soluble in acid or alkali, or heat-resistant resin powder, is applied on a substrate. Then, a method of roughening the surface of the insulating layer by dissolving the filler or the resin powder with an acid or alkali solution after curing the insulating layer formed by drying the solvent by heat is known. .

[0003]

However, according to this method, it is not possible to perform tenting on a small-diameter through hole in which parts are not soldered, and it is not possible to secure a sufficient film thickness on the pattern. The problem is that the process is complicated due to the coating and drying of the solvent solution.

Therefore, in order to secure a sufficient film thickness on the pattern, a method of thermocompression bonding a dry film resist (hereinafter referred to as "DFR") under reduced pressure is conceivable. Was difficult to roughen. Further, when the above-mentioned inorganic filler or resin powder was mixed into the conventional DFR composition component, a smooth DFR could not be manufactured.

An object of the present invention is to provide a crosslinkable curable resin composition capable of roughening the resist surface by curing with a solvent such as acid or alkali after curing.

[0006]

The gist of the present invention is to provide at least one ethylenically unsaturated compound (A) having two or more (meth) acryloyloxy groups in one molecule.
60 parts by weight, at least one kind of α, β-unsaturated carboxyl group-containing monomer (b-1) 15 to 30% by weight, at least one kind of hydroxyl group-containing monomer (b-2) 5 to 3
0% by weight and other copolymerizable monomer (b-3) 40-
Weight average molecular weight of 50,000 to 20 consisting of 80% by weight
30 to 60 parts by weight of the polymer (B) for a binder of 0.00, an α, β-unsaturated carboxyl group-containing monomer (c-
Polymer for binder (C) having a weight average molecular weight of 10,000 to 50,000, comprising at least 5 to 30% by weight of 1) and 70 to 95% by weight of another copolymerizable monomer (c-2). ) 10 to 30 parts by weight, 1 to 20 parts by weight of the block type polyisocyanate compound (D), and the above (A),
A cross-linking curable resin composition comprises 0.001 to 10 parts by weight of a photopolymerization initiator (E) based on 100 parts by weight of the total of components (B), (C) and (D).

Further, the gist of the present invention resides in a method of crosslinking and curing this resin composition by using light irradiation and heat treatment in combination.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The crosslinkable curable resin composition of the present invention is conveniently used in the form of DFR. DFR
Is prepared by dissolving a cross-linking curable resin composition in an appropriate solvent to prepare a dope, coating the dope on a supporting film such as a polyester film, and drying the dope to form a resin layer. A protective film such as a polyethylene film may be laminated on the resin layer.

The ethylenically unsaturated compound (A) having two or more (meth) acryloyloxy groups in one molecule used in the crosslinkable curable resin composition of the present invention is a polyhydric alcohol (meth) acryl. An acid ester is mentioned.
For example, 1,3-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate,
Neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2-bis [4- (meth) acryloyloxypolyethoxyphenyl] propane, 2,2-bis [ 4- (meth) acryloyloxypolypropyleneoxyphenyl] propane,
Hydroxypivalic acid neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolethane di (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane di (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tris [ethoxy (meth) acrylate], trimethylolpropane tris [diethoxy (meth) acrylate],
Trimethylolpropane tris [triethoxy (meth)
Acrylate], isocyanuric acid triethylol di (meth) acrylate, isocyanuric acid triethylol tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate
Examples thereof include acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, and dipentaerythritol penta (meth) acrylate. Furthermore, epoxy (meth) acrylates, urethane (meth) acrylates, (meth) acrylamides, etc. can be used, and these can be used 1 type or in mixture of 2 or more types.

The ethylenically unsaturated compound (A) is contained in an amount of 30 to 60 parts by weight per 100 parts by weight of the resin component. 3
When the amount is less than 0 parts by weight, the crosslink density of the obtained crosslinked cured resin becomes too low, and chemical resistance, solder heat resistance, and electrical insulation under high humidity are significantly reduced. On the other hand, when the content of the ethylenically unsaturated compound (A) exceeds 60 parts by weight, cold flow is likely to occur when DFR is used, or the crosslink density of the obtained crosslinked cured resin becomes too high. However, the polymerization shrinkage strain may increase, and the adhesion to the substrate may decrease.

In the case where the cross-linking cured resin obtained by the present invention is a protective film for a solder resist such as a flexible substrate or a base material made of glass, plastic, metal, or a composite material thereof, particularly when flexibility is required. The total (meth) acryloyl group concentration of the ethylenically unsaturated compound (A) contained in the crosslinkable curable resin composition is 0.0.
It is preferably in the range of about 01 to 0.003 mol / g. If the concentration of the (meth) acryloyl group is too low, the sensitivity of the resulting cross-linkable curable resin composition to light is lowered, which is industrially undesirable. Further, the crosslink density of the crosslinked cured resin obtained by curing this resin composition may be too low, and the solder heat resistance, solvent resistance, and electrical insulation may be reduced. On the other hand, if the concentration is too high, the resulting crosslinked cured resin becomes hard and brittle, and is not suitable as a protective film for a flexible substrate or a base material requiring flexibility.

The binder polymer (B) constituting the cross-linking curable resin composition of the present invention comprises an α, β-unsaturated carboxyl group-containing monomer (b) so that it can be developed with a dilute aqueous alkaline solution such as sodium carbonate. It is necessary to copolymerize at least one of -1) as a copolymer component in an amount of 15 to 30% by weight.

Specific examples of the monomer include (meth) acrylic acid, cinnamic acid, crotonic acid, sorbic acid,
Examples thereof include itaconic acid, propionic acid, maleic acid, and fumaric acid, and their half-esters or anhydrides can also be used. The most preferred of these are acrylic acid and methacrylic acid.

The content of the monomer (b-1) in the polymer (B) for binder needs to be in the range of 15 to 30% by weight. If it is less than 15% by weight, the development cannot be performed with an alkaline aqueous solution, or the development time becomes too long and the resolution is lowered. On the other hand, when it exceeds 30% by weight, the water absorption of the cross-linked cured resin after curing becomes large, and not only it cannot withstand alkali degreasing, but also the electrical insulation property under high humidity conditions is significantly reduced.

Since the polymer (B) for binder uses the block type polyisocyanate compound (D) as a thermal crosslinking agent, at least one kind of the hydroxyl group-containing monomer (b-2) is used as a copolymer component. To use.

Specific examples of the monomer (b-2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 2-hydroxypropyl ( Hydroxyalkyl (meth) acrylates such as (meth) acrylate and 6-hydroxyhexyl (meth) acrylate can be used.

The content of the monomer (b-2) in the binder polymer (B) is required to be in the range of 5 to 30% by weight. If it is less than 5% by weight, thermal cross-linking by the block-type polyisocyanate compound (D) becomes insufficient and the alkali resistance of the cured product decreases, which is not preferable. On the other hand, when it exceeds 30% by weight, the amount of unreacted hydroxyl groups remaining after the reaction with the compound (D) is increased, and the hydrophilicity of the crosslinked cured resin may be excessively increased. It is not preferable because it may adversely affect various electrical characteristics such as volume resistance.

Copolymerizable monomers (b-) other than the above-mentioned two kinds of monomers which are constituents of the polymer (B) for binder.
3) is not particularly limited and may be arbitrarily selected according to the purpose. Specific examples include alkyl acrylate or alkyl methacrylate in which the alkyl group has 1 to 8 carbon atoms. One or more polymerizable compounds selected may be mentioned. These may be used alone or in combination of two or more. The content of the monomer (b-3) in the binder polymer (B) is in the range of 40 to 80% by weight.

Specific examples of the alkyl acrylate useful as the monomer (b-3) include methyl acrylate, ethyl acrylate, n-propyl acrylate and iso.
-Propyl acrylate, n-butyl acrylate, s
ec-butyl acrylate, t-butyl acrylate,
2-ethylhexyl acrylate etc. are mentioned.

Examples of alkyl methacrylate include methyl methacrylate, ethyl methacrylate, n
-Propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate and the like can be mentioned.

The polymer (B) for binder preferably has a weight average molecular weight of 50,000 to 200,000. If the weight average molecular weight is too small, a cold flow phenomenon is likely to occur in DFR, and if the weight average molecular weight is too large, the unexposed area has insufficient solubility in an alkaline developer, resulting in poor developability and development time. Takes too long and tends to cause a reduction in resolution.

The binder polymer (B) used in the present invention is contained in an amount of 30 to 60 parts by weight per 100 parts by weight of the resin component. The content of the polymer (B) for binder is 3
When the amount is less than 0 parts by weight, the film forming property of the photosensitive layer of the obtained DFR is impaired, sufficient film strength cannot be obtained, and cold flow is likely to occur. On the other hand, if the amount exceeds 60 parts by weight, the solvent resistance of the cured product decreases.

The binder polymer (C) constituting the cross-linking curable resin composition of the present invention contains an α, β-unsaturated carboxyl group-containing monomer (c-) so as not to impair the developability.
It is necessary to copolymerize at least one of 1) as a copolymerization component in the range of 5 to 30% by weight. Specific examples of this monomer include those similar to (b-1).

The other copolymerizable monomer (c-2) is not particularly limited and can be arbitrarily selected according to the purpose, and is a monomer in the binder polymer (C). The content of the body (c-2) is in the range of 70 to 95% by weight. Specifically, the same thing as the above-mentioned (b-3) is illustrated. Further, a hydroxyl group-containing monomer may be copolymerized in an amount of 1 to 30% by weight depending on the purpose.

The binder polymer (C) preferably has a weight average molecular weight of 10,000 to 50,000. If the weight average molecular weight is too small, alkali resistance, solvent resistance, heat resistance and the like after curing are significantly reduced, which is not preferable. If the weight average molecular weight is too large, it becomes difficult to roughen the surface of the crosslinked cured resin after curing by acid or alkali treatment.

The binder polymer (C) used in the present invention is 1 part by weight per 100 parts by weight of the crosslinking curable resin composition.
It is contained in an amount of 0 to 30 parts by weight. Binder polymer (C)
If the content is less than 10% by weight, it is not preferable because sufficient roughening cannot be achieved even after treatment with acid or alkali after curing and sufficient adhesion strength of the conductive circuit to the surface of the insulating film cannot be obtained. On the other hand, when it exceeds 30% by weight, alkali resistance, solvent resistance, heat resistance and the like after curing are significantly lowered.

The crosslinkable curable resin composition of the present invention contains a block type polyisocyanate compound (D).
The block type polyisocyanate compound is generally called a block isocyanate or a blocked polyisocyanate, and is a compound stable at room temperature obtained by reacting a polyisocyanate compound with a compound (blocking agent) having a certain active hydrogen. is there.

Examples of the block-type polyisocyanate compound used in the present invention include tolylene diisocyanate, xylylene diisocyanate, 1,6-hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, methylene bis (4-cyclohexyl isocyanate) and trimethyl. Hexamethylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate and their adducts, biurets, isocyanurates and the like pre-polymer stabilized with a blocking agent, for safety and hygiene,
It is preferable to use a prepolymer having a low vapor pressure,
Particularly preferred are isocyanurate compounds that are chemically and thermally stable.

In the resin composition of the present invention, the isocyanate group regenerated by heat reacts with the hydroxyl group or the carboxyl group contained in the binder polymer (B) to crosslink the binder polymers (B) with each other, Makes the cured resin crosslinked by light stronger.

The block type polyisocyanate compound (D) is contained in an amount of 1 to 20 parts by weight per 100 parts by weight of the resin component. If the amount is less than 1 part by weight, a high degree of alkali resistance of the cured product cannot be sufficiently obtained. If the amount exceeds 20 parts by weight, the dissociated isocyanate groups remain in the resin in an unreacted state, which may lead to deterioration of the electrical insulating property of the cured product, which is not preferable.

As the photopolymerization initiator (E) for photopolymerizing the crosslinking curable resin composition of the present invention, conventionally known ones can be used depending on the light source such as ultraviolet rays and visible rays.
Specific examples of the UV initiator include known ones such as benzophenone, Michler's ketone, 4,4-bis (diethylamino) benzophenone, t-butylanthraquinone, 2-ethylanthraquinone, thioxanthones, benzoin alkyl ethers and benzyldimethyl ketals. Can be used, and two or more of these may be used in combination.

The photopolymerization initiator (E) is contained in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the crosslinkable resin composition of the present invention. If the content of the photoinitiator is less than 0.01 parts by weight, the composition will not be sufficiently photocured, while if it exceeds 10 parts by weight, the composition will be thermally unstable.

The cross-linking curable resin composition of the present invention may contain an adhesion promoter as another component particularly when adhesion to a metal such as copper is required.

Specific examples of the adhesion promoter include benzotriazole, tolyltriazole, carboxybenzotriazole, benzimidazole, benzothiazole, rhodanine, 5-phenyl-1H-tetrazole, 1-phenyl-5-mercaptotetrazole and 1-methyl. -5
-Mercaptotetrazole, 5-mercaptotetrazole, 5-aminotetrazole and the like can be mentioned, but an adhesion promoter containing 5-aminotetrazole as a main component is preferable from the viewpoint of improving the adhesion to the substrate. Examples of the compound that can be used in combination with 5-aminotetrazole include 5-
A heterocyclic compound containing an element that easily forms a coordinate bond with a metal, such as a tetrazole derivative other than aminotetrazole, a triazole derivative, an imidazole derivative, a thiazole derivative, and a thiadiazole derivative can be used.

The amount of the adhesion promoter added is preferably 0.005 parts by weight or more from the viewpoint of adhesion to metal. From the viewpoint of solubility and cost, it is preferably 5 parts by weight or less.

If desired, various additives such as a thermal polymerization inhibitor, a dye, a flame retardant, an isocyanate reaction catalyst, a plasticizer and a filler may be added to the crosslinkable curable resin composition of the present invention.

In the present invention, in order to obtain the desired crosslinked curable resin, it is preferable to use the above specific crosslinkable curable resin composition and to proceed the curing sufficiently.

As a method for sufficiently promoting the curing,
Various methods conventionally known in the field of paints and the like can be used. Examples of the method that can be used include ultraviolet irradiation by a high-pressure mercury lamp or the like, visible light irradiation by an argon laser or the like, since the crosslinkable curable resin composition of the present invention is composed of a photocrosslinking component and a thermal crosslinking component, It is preferable to combine heat curing with these methods.

[0039] As the ultraviolet radiation energy in the case of ultraviolet irradiation, 0.5 J / cm ² is preferably used in a range of to 10 J / cm ^2, the temperature of the substrate and the solder resist by irradiation with ultraviolet rays is excessively If you go up,
It is preferable to irradiate several times.

Further, the heat treatment used in combination with the ultraviolet irradiation treatment dissociates the blocking agent of the block type polyisocyanate compound and promotes the reaction of the produced isocyanate group,
It is effective in forming a crosslinked structure. As a heating method, for example, far-infrared heating, a heating furnace, or the like can be used.
It is preferable to carry out the treatment within the range of not more than the time.

[0041]

The present invention will be described below in more detail with reference to examples. Examples 1 to 3 and Comparative Example 1 An alkali development type DFR was manufactured under the following conditions. First, an ethylenically unsaturated compound (A), a polymer for a binder (B), a polymer for a binder (C), a blocked isocyanate compound (D), benzyl dimethyl ketal and other components are mixed and crosslinked as shown in Table 1. A curable resin composition solution was obtained.

Next, this cross-linking curable resin composition solution was applied onto a polyester film having a thickness of 20 μm so that the thickness after drying would be 75 μm, the solvent was dried by heating, and further, a polyethylene having a thickness of 30 μm was applied thereon. After stacking the films, slit both ends, width 300 mm and length 50
m was wound on a roll to prepare a DFR.

A crosslinked cured resin was formed by the following method using each of the alkali developable DFRs produced by the above method, and the performance thereof was evaluated as follows.

In Examples 1 to 4, the surface of DFR was roughened, but in Comparative Example 1, it was not roughened.

[Printed Wiring Board for Test] The following printed wiring board was used for performance evaluation as a solder resist. -Substrate; glass epoxy double-sided copper-clad laminated substrate having a solid copper portion of 5 cm x 5 cm or more [Method of forming cross-linking cured resin] (1) Laminate Using a vacuum laminator HLM-V570 (manufactured by Hitachi Capacitor Co., Ltd.) A dry film resist was laminated on a printed wiring board under the following laminating conditions. Substrate preheating roller temperature 120 ° C. Heat shoe temperature 100 ° C. Laminating pressure (cylinder pressure) 5 kgf / cm ² Pressure in vacuum chamber 10 mmHg Laminating speed 0.8 m / min (2) Exposure Solder on both sides of substrate laminated with dry film resist Photo resist masks are overlaid, and a DFR exposure machine HTE-106 (manufactured by Hitec Co., Ltd.) is used.
25-step step tablet (manufactured by Mitsubishi Rayon Co., Ltd.)
Then, the exposure was performed so that the remaining 15 steps would be left.

(3) Development The supporting film was peeled off from the exposed substrate, and spray development was carried out with a 1% sodium carbonate aqueous solution at 30 ° C. using a conveyor type developing machine. The time during which the unexposed portion can be completely removed by development was defined as the "minimum development time", and the subsequent processing and evaluation used the product developed for twice the minimum development time.

(4) Washing with water and drying The substrate after development was sprayed with tap water at room temperature for 1 minute, water on the substrate was removed with an air knife, and further dried at 70 ° C for 5 minutes.

(5) Post-curing After irradiation with ultraviolet rays from a high-pressure mercury lamp at 1 J / cm ² × 3 times, heat treatment was carried out at 180 ° C. for 1 hour.

[Evaluation Method] The sample prepared by the above-mentioned forming method was roughened by the following procedure, and the surface of the sample was observed to evaluate the degree of roughening of the surface.

(1) Mackyudizer 9 heated to 70 ° C.
After immersing in 204JH (hole conditioner solution made by MacDermid Japan) for 5 to 10 minutes, it was washed with water and drained for 3 minutes.

(2) Immersion in a 7% potassium permanganate aqueous solution heated to 80 ° C. for 5 minutes, followed by washing with water for 6 minutes and draining.

[0052]

[Table 1]

[0053]

EFFECTS OF THE INVENTION The cross-linking curable resin composition of the present invention can be used as an interlayer insulating film of a multi-layer printed circuit board by a build-up method because the resist surface can be roughened by treatment with a solvent such as acid or alkali after curing. can do.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03F 7/031 G03F 7/031 7/40 501 7/40 501 H05K 3/28 H05K 3/28 D 3/38 7511-4E 3/38 D 3/46 3/46 T (72) Inventor Hiroyuki Otani 20-1 Miyukicho, Otake-shi, Hiroshima Mitsubishi Rayon Co., Ltd.

Claims (2)

[Claims] 1. At least one 30 to 60 parts by weight of an ethylenically unsaturated compound (A) having two or more (meth) acryloyloxy groups in one molecule, and an α, β-unsaturated carboxyl group-containing unit amount. At least one kind of body (b-1) 15
To 30% by weight, 5 to 30% by weight of at least one kind of the hydroxyl group-containing monomer (b-2), and 40 to 80% by weight of the other copolymerizable monomer (b-3). 30 to 60 parts by weight of the polymer (B) for binder of 50,000 to 200,000, 5 to 30% by weight of at least one kind of the α, β-unsaturated carboxyl group-containing monomer (c-1), other Copolymerizable monomer (c-2) 70 to 95% by weight, weight average molecular weight 10,000 to 50,000
10 to 30 parts by weight of the binder polymer (C), 1 to 20 parts by weight of the block-type polyisocyanate compound (D),
And a total of 1 of the components (A), (B), (C), and (D)
The photopolymerization initiator (E) is 0.001 to 100 parts by weight.
A cross-linking curable resin composition containing 10 parts by weight. 2. A method of cross-linking and curing the cross-linking curable resin composition according to claim 1 by using light irradiation and heat treatment in combination.