JPH10182946A - Epoxy resin composition for printed wiring board and prepreg using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for a printed wiring board which has properties as a base and prevents the plating solution from intrusion along the interface between a copper circuit and cured resin, thus making the surface-treatment film difficult to dissolve, and provides excellent acid resistance for the printed-wiring board. SOLUTION: This epoxy resin composition comprises (A) an epoxy resin that has two or more epoxy groups in a molecule, (B) a phenolic-resin curing agent which has two or more phenolic OHs in a molecule, (C) a curing accelerator, and (D) a basic compound [for example, a basic organic compound having a converted basicity of 7-10, preferably benzoguanamine, guanidine phosphate, (phenyl)diguanide, etc.], in a quantity of (D) of 0.2-3 pts.wt. based on 100 pts.wt. of A+B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition used for manufacturing a printed wiring board, and a prepreg using the same.

[0002]

2. Description of the Related Art A multilayer printed wiring board used for electric / electronic equipment is manufactured by, for example, the following method.
After impregnating a base material such as a glass cloth with a thermosetting resin composition such as an epoxy resin composition, a prepreg is prepared by heating and drying and semi-curing, and a required number of prepregs are stacked and a copper foil is formed. The copper foil-clad laminate for the inner layer material is manufactured by arranging and laminating on one side or both sides and performing molding by heating and pressing.

[0003] Next, the copper foil on the surface of the laminate is etched to form a copper circuit for the inner layer, and the copper circuit is subjected to a surface treatment to increase the adhesive strength. The copper foil for the outer layer is placed on one side or both sides and laminated, and the laminate is produced by applying heat and pressure to form a multilayer laminate.

[0004] Next, a hole is made in this multilayer laminate,
This hole is subjected to through-hole plating for conducting the inner layer and the outer layer copper foil, and then the outer layer copper foil is etched to form an outer layer circuit.Then, on the surface of a portion other than the outer layer circuit to be connected to the electronic component, It is manufactured by a method of forming a solder resist film so that solder does not adhere.

The surface treatment performed on the copper circuit for the inner layer is generally performed by a chemical oxidation treatment called a blackening treatment. This blackening treatment is a treatment that is performed on a copper circuit to form fine irregularities on the surface and improve the adhesiveness of the copper circuit, and the surface of the copper circuit is turned into black because it becomes copper oxide. It is.

On the other hand, when producing the above prepreg,
When using an epoxy resin composition as the thermosetting resin,
In order to secure the storage stability of the prepreg and the heat resistance of the laminate, it is common to use an amine-based curing agent such as dicyandiamide as the curing agent. However, with the recent increase in mounting density, laminates having better heat resistance and moisture resistance have been demanded more than before, and phenol-based phenols which are more excellent in moisture resistance and heat resistance than conventional amine-based curing agents are required. Are being studied.

However, when a multi-layer printed wiring board is manufactured using a prepreg using an epoxy resin composition containing a phenolic curing agent, the acid such as a plating solution used in a through-hole plating process may cause holes. In some cases, the surrounding treatment film is dissolved, the black color changes to pink, and a phenomenon called haloing occurs, which causes a problem in appearance. Therefore, there is a need for an epoxy resin composition that can provide a printed wiring board having excellent acid resistance, in which a surface treatment film is not easily dissolved.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an epoxy resin composition for printed wiring boards containing a phenolic curing agent. Accordingly, an object of the present invention is to provide an epoxy resin composition capable of obtaining a printed wiring board having excellent acid resistance. Another object of the present invention is to provide a prepreg capable of obtaining a printed wiring board having excellent acid resistance.

[0009]

An epoxy resin composition for a printed wiring board according to claim 1 of the present invention comprises an epoxy resin having two or more epoxy groups in a molecule and two phenolic hydroxyl groups in a molecule. It is characterized by containing a phenolic curing agent having the above, a curing accelerator, and a basic compound.

According to a second aspect of the present invention, there is provided the epoxy resin composition for a printed wiring board according to the first aspect, wherein the basic compound is a basic organic compound. Features.

The epoxy resin composition for a printed wiring board according to claim 3 of the present invention is the epoxy resin composition for a printed wiring board according to claim 1 or 2, wherein the reduced basicity of the basic compound is 7 or less. -10.

The epoxy resin composition for a printed wiring board according to claim 4 of the present invention is the epoxy resin composition for a printed wiring board according to any one of claims 1 to 3, wherein It is characterized by containing the compound of (a). (A) at least one selected from the group consisting of benzoguanamine, guanidine phosphate, diguanide and phenyldiguanide.

According to a fifth aspect of the present invention, there is provided an epoxy resin composition for a printed wiring board according to any one of the first to fourth aspects. It is characterized by containing 0.2 to 3 parts by weight of a basic compound with respect to 100 parts by weight of the total of the agent.

A prepreg according to a sixth aspect of the present invention is obtained by impregnating a substrate with the epoxy resin composition for a printed wiring board according to any one of the first to fifth aspects.

A prepreg according to a seventh aspect of the present invention is the prepreg according to the sixth aspect, wherein the base material is a glass cloth.

The reduced basicity according to the present invention means that 4 parts by weight of a compound is mixed with 100 parts by weight of pure water, and the mixture is extracted at 133 ° C. for 4 hours using a pressure cooker. After filtration, and then controlling the temperature of the filtrate at 25 ° C., the hydrogen index is measured by a pH meter.

According to the present invention, since a basic compound is contained in the epoxy resin composition, the epoxy resin composition containing a slightly acidic phenolic curing agent changes to basic, and the resin cured product of the copper circuit and the prepreg is changed. It is considered that the infiltration of the plating solution along the interface with the film is suppressed, the treatment film of the surface treatment is hardly dissolved, and the acid resistance is improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin composition for a printed wiring board according to the present invention comprises an epoxy resin having two or more epoxy groups in a molecule and a phenolic hydroxyl group in a molecule.
An epoxy resin composition containing at least one phenolic curing agent, a curing accelerator, and a basic compound.

The epoxy resin used in the present invention may be any epoxy resin having an average of two or more epoxy groups in one molecule, such as bisphenol A epoxy resin and bisphenol F epoxy resin. Phenol novolak type epoxy resin, bisphenol A novolak type epoxy resin, cresol novolak type epoxy resin, diaminodiphenylmethane type epoxy resin, trifunctional type epoxy resin and halogenating a part of hydrogen atoms in these epoxy resin structures Alone, modified products, and mixtures of epoxy resins and the like flame-retarded by the above method.

The phenolic curing agent used in the present invention comprises:
Any phenolic curing agent having two or more phenolic hydroxyl groups in one molecule may be used, and examples thereof include a phenol novolak resin, a cresol novolak resin, and a p-xylene-novolak resin. Or two or more of them may be used in combination.

The curing agents that can be contained are not limited to phenolic curing agents, but include amide-based curing agents such as dicyandiamide and aliphatic polyamides, and aliphatic amine-based curing agents such as ammonia, triethylamine, and diethylamine. A curing agent, an aromatic amine curing agent such as diaminodiphenylmethane and metaphenylenediamine, and an acid anhydride curing agent such as methylhexahydrophthalic anhydride may be used in combination. When a curing agent other than the phenolic curing agent is contained, it is preferable to contain the phenolic curing agent in a functional group ratio of 50% or more, since heat resistance and moisture resistance are particularly excellent. Incidentally, the total amount of the curing agent is usually 0.5 equivalent ratio to the epoxy resin.
It is blended in the range of ~ 1.5. If it is less than 0.5 or more than 1.5, the heat resistance of the obtained laminate may decrease.

The curing accelerator used in the present invention is not particularly limited, but includes 2-methylimidazole,
Imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole; tertiary amines such as 1,8-diaza-bicyclo [5.4.0] undecene-7, triethylenediamine and benzyldimethylamine; tributyl Examples thereof include organic phosphines such as phosphine and triphenylphosphine, and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. These may be used alone or in combination of two or more. Is also good.
Usually, the content of the curing accelerator is preferably about 1 part by weight or less based on 100 parts by weight of the solid content of the epoxy resin composition.

When the curing accelerator contains at least one selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, tributylphosphine and triphenylphosphine, The balance between the acceleration of curing and the preservability of the prepreg is excellent and is preferable.

It is important that the epoxy resin composition according to the present invention contains a basic compound. When manufacturing a multilayer printed wiring board using a prepreg using an epoxy resin composition that does not contain this basic compound,
An acid such as a plating solution used in the through-hole plating process may dissolve the treatment film around the hole, and the acid resistance may be reduced.

This is because, when a basic compound is contained in the epoxy resin composition, the epoxy resin composition containing the slightly acidic phenolic curing agent changes to basic, and the interface between the copper circuit and the cured resin of the prepreg is changed. It is considered that the infiltration of the plating solution along the surface is suppressed, the treated film of the surface treatment is hardly dissolved, and the acid resistance is improved.

The basic compound used in the present invention includes:
If it is a compound that can be mixed with the epoxy resin composition and can change the epoxy resin composition into a basic liquid,
Although not particularly limited, organic bases such as aniline, benzoguanamine, guanidine phosphate, diguanide, phenyldiguanide and the like, and inorganic bases such as sodium hydroxide and potassium hydroxide can be mentioned.

The basic compound was prepared in terms of reduced basicity (4 parts by weight of the compound was added to 100 parts by weight of pure water, and the mixture was extracted at 133 ° C. for 4 hours using a pressure cooker. Then, the filtrate is adjusted to a temperature of 25 ° C., and the hydrogen index is measured with a pH meter. When the reduced basicity is less than 7, the effect of improving acid resistance is not remarkable, and the reduced basicity is 1
If it exceeds 0, the storage stability of the obtained prepreg decreases,
The usable time of the prepreg may be shortened.

When the basic compound contains at least one selected from the group consisting of benzoguanamine, guanidine phosphate, diguanide and phenyldiguanide, the effect of improving the acid resistance and the preservability of the prepreg can be obtained. Is excellent and the balance is preferable. In particular, when benzoguanamine is contained, the effect of improving the acid resistance is large, which is preferable.

The content of the basic compound is 0.2 parts by weight based on 100 parts by weight of the total of the epoxy resin and the phenolic curing agent.
It is preferable that the content be 3 to 3 parts by weight. When the amount is less than 0.2 part by weight, the effect of improving the acid resistance is not remarkable, and when it exceeds 3 parts by weight, the storage stability of the obtained prepreg may decrease.

The epoxy resin composition of the present invention may contain a solvent, an inorganic filler and the like, if necessary.
The solvent that can be contained is not particularly limited as long as it can obtain a uniform solution of the resin composition, but acetone, ketones such as methyl ethyl ketone, and ethers such as ethylene glycol monomethyl ether. , Aromatic hydrocarbons such as benzene and toluene, methoxypropanol and the like. Examples of the inorganic filler that can be contained include inorganic powder fillers such as silica, calcium carbonate, aluminum hydroxide, and talc, and fibrous fillers such as glass fiber, pulp fiber, synthetic fiber, and ceramic fiber. Can be These solvents and inorganic fillers may be used alone or in combination of two or more.

The epoxy resin composition obtained in the present invention is impregnated into a substrate and dried by heating to produce a prepreg. The substrate is not particularly limited, and cloth or nonwoven fabric using fibers such as glass fiber, aramid fiber, polyester fiber, and nylon fiber, or paper such as kraft paper and linter paper can be used. In addition, inorganic fibers such as glass cloth are preferable because they have excellent heat resistance and moisture resistance.

The amount of the prepreg resin is preferably 40 to 80 parts by weight based on 100 parts by weight of the prepreg. If the amount is less than 40 parts by weight, air bubbles may remain in the laminated plate manufactured using the prepreg, or a plate thickness defect may occur. Also, when the amount exceeds 80 parts by weight, a sheet thickness defect may occur.

[0033]

【Example】

(Examples 1 to 7, Comparative Examples 1 and 2) The following two types of epoxy resins, phenolic curing agents, two types of curing accelerators, two types of basic compounds, and two types of epoxy resin compositions Solvent was used. The converted basicity of the basic compound was determined by mixing 4 parts by weight of each of the following basic compounds with 100 parts by weight of pure water and using a pressure cooker at 133 ° C.
After performing extraction for a time, the extract was filtered, then the filtrate was adjusted to 25 ° C., and the hydrogen index was measured with a pH meter to obtain the value. Epoxy resin 1: Tetrabromobisphenol A type epoxy resin having an epoxy equivalent of 500 [DER511, manufactured by Dow Chemical Co., Ltd.] Epoxy resin 2: Cresol novolac type epoxy resin having an epoxy equivalent of 200 [Toto Kasei ( Co., Ltd., trade name: YDCN702] Phenolic curing agent: phenolic hydroxyl equivalent 105
Phenol novolak resin [Arakawa Chemical Industry Co., Ltd.
Trade name Tamanol 752] Curing accelerator 1: 2-ethyl-4-methylimidazole [reagent] Curing accelerator 2: triphenylphosphine [reagent] Basic compound 1: benzoguanamine having a reduced basicity of 7.8 [Reagent] Basic compound 2: Organic compound having a reduced basicity of 9.5 [Adeka Stab ZS-2 manufactured by Asahi Denka Kako Co., Ltd.]
7]-Solvent 1: methyl ethyl ketone [reagent]-Solvent 2: propylene cellosolve [reagent].

Each of the above raw materials was blended at the ratio shown in Table 1,
After mixing and dissolving, a varnish-like epoxy resin composition was obtained.
Next, the obtained epoxy resin composition was impregnated into a glass cloth [trade name: 216L, manufactured by Asahi Schwebel Co., Ltd.], and then dried at 150 ° C. to have a thickness of 0.1 mm and a resin content of about 50% by weight. A prepreg was prepared.

[0035]

[Table 1]

(Evaluation) The acid resistance, storage stability, glass transition temperature and moisture absorption of the obtained prepreg were measured by the following measuring methods.

Acid resistance: FR-4 type, thickness 0.7m
m double-sided copper-clad laminate [Matsushita Electric Works, Ltd., product number R176
6] A copper foil (thickness: 70 μm) whose surface is treated with copper oxide is used as an inner layer substrate, three prepregs obtained above are arranged on both sides thereof, and a 18 μm thick copper foil is arranged on both outer sides. Then, the laminate was sandwiched between metal plates, and heated and pressed under the conditions of a temperature of 170 ° C., a pressure of 3.9 MPa, and a time of 90 minutes to produce a multilayer laminate.

Next, at the position where the copper foil treated with copper oxide is present in the inner layer, a drill having a diameter of 0.4 mm [trade name: UC30, manufactured by Union Tool Co., Ltd.] was used. 50 holes were drilled at a feed rate of 6.6 m / min, and then added to a 17.5% by weight aqueous hydrochloric acid solution at 20 ° C.
After immersion for 60 minutes, rinse immediately with water,
The outer layer copper foil and the insulating layer where the prepreg is hardened are partly removed to expose the inner layer copper foil. Measured with a mirror.

The above copper foil surface is treated with copper oxide by buffing the copper foil surface, immersing it in a copper chloride solution for 25 seconds, washing with water, then immersing it in a hydrochloric acid solution for 60 seconds, washing with water, and then washing with 95% water.
This was performed by immersing in an aqueous solution containing sodium chlorite, sodium phosphate and sodium hydroxide at 2 ° C. for 2 minutes, washing with water, and drying.

The storability was determined by storing each of the prepregs obtained above in a constant temperature / humidity bath at 20 ° C. and 50% for 2 weeks and 4 weeks. Are laminated, and then the laminate is sandwiched between metal plates at a temperature of 170 ° C. and a pressure of 3.9.
A test piece was prepared by heating and pressing under the conditions of MPa and a time of 90 minutes. Then, after etching the copper foil on the surface layer of the test piece, the external appearance was visually judged, and the case where air bubbles were present in the test piece was evaluated as x, and the case where no air bubbles were present in the test piece was evaluated as ○.

The glass transition temperature was determined by laminating three prepregs each other, arranging release sheets on both outer sides of the prepregs, and then laminating the laminate with a metal plate. After heating and pressurizing under a condition of 0.9 MPa and a time of 90 minutes, a laminate obtained by peeling the release sheet was used as a test piece. Then, the temperature dispersion of the dynamic viscoelasticity of the test piece was measured, and the glass transition temperature was determined from the obtained tan δ peak temperature.

The moisture absorption was determined by preparing a test piece in the same manner as the test piece for which the glass transition temperature was measured, except that the obtained prepregs were stacked on each of the eight prepregs, and then stored in a thermo-hygrostat at 85 ° C. and 85%. The moisture absorption treatment was performed for 7 days. Then, from the measured value of the weight of the test piece before and after the moisture absorption treatment, the moisture absorption rate by the moisture absorption treatment was calculated and obtained.

(Results) As shown in Table 1, the glass transition temperature and the moisture absorption of each example were almost the same as those of the comparative examples, but it was confirmed that the acid resistance was good.
Further, Examples 1, 2, 4 to 7 containing 0.2 to 3 parts by weight of the basic compound with respect to 100 parts by weight of the total of the epoxy resin and the phenolic curing agent had better storage stability than Example 3. It was confirmed that there was.

[0044]

Since the epoxy resin composition according to any one of claims 1 to 5 of the present invention contains a basic compound, it has excellent acid resistance even if it contains a phenolic curing agent as a curing agent. A wiring board can be obtained.

The epoxy resin composition according to the fifth aspect of the present invention makes it possible to obtain a prepreg having good preservability in addition to the above effects.

Since the prepreg according to claims 6 and 7 of the present invention uses an epoxy resin composition containing a basic compound, it is possible to obtain a printed wiring board having excellent acid resistance.

Claims (7)

[Claims] An epoxy resin having two or more epoxy groups in a molecule, a phenolic curing agent having two or more phenolic hydroxyl groups in a molecule, a curing accelerator, and a basic compound. Characterized by an epoxy resin composition for printed wiring boards. 2. The epoxy resin composition for a printed wiring board according to claim 1, wherein the basic compound is a basic organic compound. 3. The reduced basicity of the basic compound is from 7 to 10.
The epoxy resin composition for a printed wiring board according to claim 1 or 2, wherein 4. The epoxy resin composition for a printed wiring board according to claim 1, further comprising a compound represented by the following (a) as the basic compound. (A) at least one selected from the group consisting of benzoguanamine, guanidine phosphate, diguanide and phenyldiguanide. 5. The method according to claim 1, wherein the basic compound is contained in an amount of 0.2 to 3 parts by weight based on 100 parts by weight of the total of the epoxy resin and the phenolic curing agent. Epoxy resin composition for printed wiring boards. 6. A prepreg, wherein a base material is impregnated with the epoxy resin composition for a printed wiring board according to any one of claims 1 to 5. 7. The prepreg according to claim 6, wherein the substrate is a glass cloth.