JPH11152354A - Production of prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prepreg which can stably give a laminate excellent in humidity resistance and heat resistance by mixing a bisphenol S epoxy resin in a state heated to a specified temperature with a bisphenol A epoxy resin and a curing agent and impregnating a base with the obtained resin composition. SOLUTION: The bisphenol S epoxy resin desirably having an epoxy equivalent of about 100-600 and being in a state heated to 70-90 deg.C is mixed with the bisphenol A epoxy resin desirably having an epoxy equivalent of about 100-800 and a curing agent being desirably dicyandiamide, and a base (e.g. glass cloth) is impregnated with the obtained resin composition, It is desirable that the bisphenol S epoxy resin is used in an amount of 5-15 pts.wt. (in terms of the solid matter), per 100 pts.wt. solids of the epoxy resin composition. As a result, it seldom occurs that the curing agent crystallizes and precipitates during the storage of the epoxy resin composition, and the obtained laminate resists to deterioration in humidity resistance and heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a prepreg used for producing a laminate used for electric / electronic equipment.

[0002]

2. Description of the Related Art A laminated board used for manufacturing a printed wiring board is prepared by impregnating a base material such as a glass cloth with an epoxy resin composition containing an epoxy resin and a curing agent and then heating the B-stage. The prepreg is manufactured by forming (semi-curing) the required number of prepregs, stacking a required number of such prepregs, and arranging metal foils such as copper foils on one side or both sides as necessary, and then heating and pressurizing to manufacture. ing.

[0003] In order to obtain a viscosity suitable for impregnating the inside of the substrate, the above-mentioned epoxy resin composition is generally mixed with a bisphenol A type epoxy resin as an epoxy resin. However, when an epoxy resin composition containing only a bisphenol A-type epoxy resin is used as the epoxy resin, there are problems in the adhesive strength, heat resistance to moisture absorption and the like of the obtained laminate.

For this reason, for example, Japanese Patent Application Laid-Open No. 61-23514
As described in No. 5, a method using an epoxy resin composition in which a bisphenol A type epoxy resin and a bisphenol S type epoxy resin are blended has been proposed. However, even when a prepreg is manufactured using an epoxy resin composition containing this bisphenol S-type epoxy resin, there is a problem that the moisture absorption heat resistance of the obtained laminate may be reduced.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a bisphenol A type epoxy resin, a bisphenol S type epoxy resin, and a curing agent. A method for producing a prepreg produced by impregnating a base material with an epoxy resin composition containing the same, and a method for producing a prepreg capable of stably obtaining a laminated board having excellent heat resistance to moisture absorption. .

[0006]

According to a first aspect of the present invention, there is provided a method for producing a prepreg, comprising: an epoxy resin composition containing a bisphenol A type epoxy resin, a bisphenol S type epoxy resin, and a curing agent; A method for producing a prepreg by impregnating a material with bisphenol A
The method of mixing the epoxy resin, the bisphenol S epoxy resin, and the curing agent is a method of mixing the bisphenol S epoxy resin with other components while heating the bisphenol S epoxy resin to 70 to 90 ° C. I do.

According to a second aspect of the present invention, there is provided a method for producing a prepreg according to the first aspect, wherein the bisphenol S-type epoxy resin is mixed with the solid content of 100 parts by weight of the epoxy resin composition. 5-15
It is characterized by being blended by weight.

According to a third aspect of the present invention, there is provided a method for producing a prepreg according to the first or second aspect, wherein dicyandiamide is blended as a curing agent.

According to the present invention, when a bisphenol S type epoxy resin is heated to 70 to 90 ° C. and mixed with other components, a hardener which is hardly soluble in epoxy resin such as dicyandiamide is used as a hardener. Even in this case, the hardening agent hardly crystallizes and precipitates during storage of the epoxy resin composition. For this reason, the heat resistance to moisture absorption of the obtained laminate is less likely to decrease, and a laminate excellent in heat resistance to moisture absorption can be stably obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a prepreg according to the present invention comprises impregnating a base material with an epoxy resin composition containing at least a bisphenol A type epoxy resin, a bisphenol S type epoxy resin and a curing agent. This is a method for producing a prepreg.

The bisphenol A type epoxy resin used in the present invention is not particularly limited, but preferably has an epoxy equivalent of about 100 to 800. In the bisphenol A type epoxy resin of the present invention, a part of hydrogen atoms in a bisphenol A type epoxy resin structure such as a brominated bisphenol A type epoxy resin and a chlorinated bisphenol A type epoxy resin may be halogenated. It also includes resins that have become flame-retardant.

The bisphenol S used in the present invention
The type epoxy resin is not particularly limited, but those having an epoxy equivalent of about 100 to 600 are preferable. The bisphenol S type epoxy resin is preferably blended in an amount of 5 to 15 parts by weight on a solid basis with respect to 100 parts by weight of the solids of the epoxy resin composition. When the amount is less than 5 parts by weight, the effect of blending the bisphenol S type epoxy resin is small, so that the moisture absorption heat resistance may be reduced. When the amount exceeds 15 parts by weight, when the curing agent used is a curing agent that is hardly soluble in epoxy resin such as dicyandiamide, the solubility decreases, and the curing agent becomes crystalline while the epoxy resin composition is stored. This causes a problem that the heat resistance to moisture absorption of the obtained laminate decreases.

The epoxy resin contained in the epoxy resin composition is not limited to bisphenol A-type epoxy resin and bisphenol S-type epoxy resin, but may include other epoxy resins having two epoxy groups in the molecule. An epoxy resin having three or more epoxy groups in the molecule may also be contained. Examples of the epoxy resin that can be contained include bisphenol F type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin, novolak type epoxy resin and epoxy obtained by halogenating these resins. Resins and the like may be used, and two or more kinds may be used in combination.

The curing agent used in the present invention includes:
There is no particular limitation as long as it cures by reacting with an epoxy resin. Curing agent, bisphenol A, bisphenol F, phenol novolak resin, cresol novolak resin, p-xylene-
Examples include phenolic curing agents such as novolak resins, acid anhydrides, and the like, and two or more kinds may be used in combination. When dicyandiamide is blended, the obtained prepreg has excellent storage stability and is preferable.

[0015] It is practical to add a curing accelerator to the epoxy resin composition in order to accelerate the curing reaction. As the curing accelerator that can be contained, for example, 2-
Imidazoles such as methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole,
1,8-diaza-bicyclo [5.4.0] undecene-
7, tertiary amines such as triethylenediamine and benzyldimethylamine; organic phosphines such as tributylphosphine and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. Two or more types may be used in combination.

The epoxy resin composition may contain an inorganic filler, a solvent, and the like, if necessary. As an inorganic filler that can be contained, silica powder,
Examples thereof include glass fiber and talc, and two or more kinds may be used in combination. Further, as a solvent that can be contained,
Organic solvents such as toluene, xylene, benzene, ketone, and alcohols are exemplified.

Then, an epoxy resin composition is produced by blending and mixing a bisphenol A type epoxy resin, a bisphenol S type epoxy resin, a curing agent and the like.
At this time, the bisphenol S-type epoxy resin was
It is important to mix with other components while heating to ~ 90 ° C. 70 ℃ of bisphenol S type epoxy resin
If less than, when using a hardening agent hardly soluble in an epoxy resin such as dicyandiamide as a hardening agent, the hardening agent is easily crystallized and stored during storage of the epoxy resin composition, so that it is obtained. The moisture absorption heat resistance of the laminate is reduced, which is problematic. When the temperature of the bisphenol S-type epoxy resin exceeds 90 ° C., the temperature of the epoxy resin composition obtained by mixing increases, and the reaction between the epoxy resin and the curing agent proceeds, which is problematic.

Next, the obtained epoxy resin composition is
After impregnating the base material, the prepreg is manufactured by heating as needed to advance the curing. The method is not particularly limited. For example, after a substrate is immersed in an epoxy resin composition to be impregnated, the solvent is removed by heating and the epoxy resin composition is semi-cured (B-staged). A prepreg is produced by a method or a method in which a solid epoxy resin composition is heated and melted at room temperature, then applied to one surface of a substrate and impregnated, and then cooled. The amount of the resin impregnated in the base material is not particularly limited, but it is preferable to impregnate the resin so that the resin content after removing the solvent is 30 to 70% by weight based on the weight of the prepreg. 3
When the amount is less than 0% by weight, air bubbles may remain in the obtained laminate, and the electrical reliability may decrease. When the amount exceeds 70% by weight, the thickness of the obtained laminate may vary. May be larger.

The substrate used in the present invention is not particularly limited, but cloth or nonwoven fabric using fibers such as glass fiber, aramid fiber, polyester fiber, nylon fiber, etc., or paper such as kraft paper, linter paper, etc. Can be used. In addition, inorganic fibers such as glass cloth are preferable because they have excellent heat resistance and moisture resistance.

Then, a required number of the prepregs are stacked, and a metal foil such as a copper foil is arranged on one or both sides of the prepreg and laminated, and heated and pressed to form a laminate. In addition, a laminate obtained by forming a copper circuit on the surface (the one manufactured using the prepreg according to the present invention or the one manufactured using another prepreg) may be obtained on both sides or one side thereof. A prepreg is provided, a metal foil is further provided on the outside of the prepreg, and the prepreg is laminated. Then, the laminate is formed by applying heat and pressure to obtain a laminate having a circuit in an inner layer.

In general, when an epoxy resin containing a sulfur atom in a molecule, such as a bisphenol S type epoxy resin, is used, the obtained laminate is hardened and the amount of wear of a drill is likely to increase. It is preferable that the thickness of the plate is 0.6 mm or less.

[0022]

EXAMPLES (Example 1) The following three types of epoxy resins, curing agents, curing accelerators and two types of solvents were used as raw materials for epoxy resin compositions. -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 novolak type epoxy resin having an epoxy equivalent of 220 [Toto Kasei Co., Ltd.
Epoxy resin 3: a bisphenol S-type epoxy resin having an epoxy equivalent of 300 [EPICLON EXA-1514, manufactured by Dainippon Ink and Chemicals, Inc.]
・ Curing agent: dicyandiamide [reagent] ・ Curing accelerator: 2-ethyl-4-methylimidazole [manufactured by Shikoku Chemicals Co., Ltd.] ・ Solvent 1: dimethylformamide (DMF) [reagent]
Solvent 2: methyl ethyl ketone (MEK) [reagent].

The bisphenol S type epoxy resin is heated to 80 ° C. and mixed with other components by blending the above-mentioned raw materials in the weight ratios shown in Table 1 and mixing. A resin composition was obtained. The weight of each epoxy resin in the table represents the weight of the solid content. This epoxy resin composition, bisphenol S-type epoxy resin, 100 parts by weight of the solid content of the epoxy resin composition,
It is an epoxy resin composition containing 10 parts by weight in solid content.

[0024]

[Table 1]

Next, the obtained epoxy resin composition is
After impregnating a glass cloth of 0.06 mm thickness, 150
The resin was semi-cured by heating at 9 ° C. for 9 minutes, and the solvent was removed.
8% by weight of prepreg was obtained.

Next, an inner layer substrate having a conductor circuit formed on both surfaces is prepared by etching a copper foil (thickness 0.018 mm) of a copper-clad laminate having a thickness of 0.06 mm [trade name: R1766, manufactured by Matsushita Electric Works, Ltd.] And on the front and back of the inner layer substrate,
Each of the obtained prepregs was laminated three by three, and a copper foil having a thickness of 18 μm was further laminated on the outside thereof. The laminate was sandwiched between metal plates, and heated and pressed at a maximum temperature of 170 ° C. and a pressure of 3 MPa for 70 minutes. Thus, a four-layer laminate having a thickness of about 0.5 mm was obtained.

Example 2 The same procedure as in Example 1 was repeated except that the obtained prepregs were laminated one by one on the front and back surfaces of the inner layer substrate, and a copper foil having a thickness of 18 μm was further laminated on the outside thereof. A four-layer laminate of 0.3 mm was obtained.

Comparative Example 1 An epoxy resin composition obtained by mixing a bisphenol S type epoxy resin at room temperature with other components was used in the same manner as in Example 1 except that an epoxy resin composition having a thickness of about 0.5 mm was used. A four-layer laminate was obtained.

(Comparative Example 2) As shown in Table 1, except that a liquid epoxy resin composition containing no bisphenol S type epoxy resin was used, the same procedure as in Example 1 was repeated except that a liquid epoxy resin composition having a thickness of about 0.5 mm was used. A four-layer laminate was obtained.

(Evaluation and Results) The heat resistance to moisture absorption and the abrasion resistance of the drills of the four-layer laminates obtained in each of the examples and comparative examples were measured. The method for measuring the moisture absorption heat resistance is as follows: after removing the copper foil on the surface, cutting it into 50 × 50 mm, then boiling it in ion-exchanged water for 60 minutes, immersing it in 260 ° C. solder for 20 seconds, Among the samples, the number of samples in which abnormalities such as blistering and measling were not observed was counted.

The drill abrasion was measured by measuring the area ratio of the worn blade edge by performing 4,500 hits of a hole having a diameter of 0.4 mm on four obtained four-layer laminates. .

The results are shown in Table 1. It was confirmed that the four-layer laminate obtained in each of the examples had better moisture absorption and heat resistance than the four-layer laminate obtained in each of the comparative examples. . Also,
It was confirmed that the four-layer laminate obtained in each example had substantially the same drill wear rate as the four-layer laminate obtained in Comparative Example 2 which did not contain the bisphenol S-type epoxy resin.

[0033]

The method for producing a prepreg according to the present invention comprises:
A bisphenol S-type epoxy resin is heated to 70 to 90 ° C., and an epoxy resin composition mixed with other components is impregnated into a base material to manufacture the laminate. It is possible to obtain.

Claims (3)

[Claims] 1. A method for producing a prepreg, comprising impregnating a base material with an epoxy resin composition containing a bisphenol A type epoxy resin, a bisphenol S type epoxy resin, and a curing agent, the method comprising the steps of: And a method of mixing a bisphenol S-type epoxy resin and a curing agent, wherein the bisphenol S-type epoxy resin is heated to 70 to 90 ° C. and mixed with other components. Production method. 2. The prepreg according to claim 1, wherein the bisphenol S type epoxy resin is blended in an amount of 5 to 15 parts by weight on a solid basis with respect to 100 parts by weight of a solids on the epoxy resin composition. Method. 3. The method for producing a prepreg according to claim 1, wherein dicyandiamide is blended as a curing agent.