JPH06239963A - Epoxy resin composition for laminate - Google Patents

Abstract

PURPOSE:To obtain the subject composition prepared by using an epoxy resin synthesized according to a specified method, excellent in ability for impregnating glass cloth, etc., and capable of forming a cured material excellent in heat resistance, blister resistance, etc., and suitable for a copper-clad epoxy laminate. CONSTITUTION:This resin composition is obtained by reacting a mixture of (A) a bisphenol (preferably bisphenol A) and (B) novolak resin with (C) a (methyl)epihalohydrin (preferably epichlorohydrin, etc.) and subsequently further reacting the resultant glycidyl etherified epoxy resin with (D) a halogenated bisphenol (preferably tetrabromobisphenol A, etc.). In addition, the reaction of the components (A) and (B) with the component (C) is carried out preferably by allowing an etherification reaction and a dehydrohalogenation reaction to take place in order. The etherification reaction is carried out generally in an inert atmosphere at 60 to 110 deg.C and the dehydrohalogenation reaction is carried out at 60 to 90 deg.C under 100 to 300mmHg for 1 to 6 hr in general.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can provide a cured product having particularly good impregnating ability for glass cloth and the like and excellent heat resistance and blister resistance. Therefore, it can be used for printed wiring boards and multilayer printed wiring. The present invention relates to an epoxy resin composition preferably used for producing a copper-clad epoxy resin plate for a plate.

[0002]

2. Description of the Related Art In recent years, the variety of electronic devices has expanded greatly, and not only computer-related devices but also automatic control devices,
The use of multilayer printed wiring boards has come to increase due to improvements in functions and miniaturization of communication equipment, office equipment, game equipment and the like.

On the other hand, in the computer field, there is a change in the system configuration, which is called downsizing,
Distributed systems centering on workstations are emerging. The printed wiring boards used for these devices are mainly oriented to 4 to 10 layers, not in the direction of increasing the number of layers. The printed wiring board used in this case is being studied for thinning in addition to the phi pattern in order to achieve high-density mounting. In order to meet the demands on these printed wiring boards, further improvement in heat resistance and blister resistance of the base material used for the wiring boards is desired.

In order to improve the heat resistance of a cured epoxy resin product, it has been practiced to add a polyfunctional epoxy resin such as a phenol novolac type epoxy resin to the epoxy resin to be used, but these polyfunctional epoxy resins are added. Just by doing, the heat resistance was no longer sufficient. In order to improve heat resistance, when the amount of polyfunctional epoxy resin added is increased, the resulting composition becomes hard and brittle, so if the laminate obtained using these is treated by soldering after boiling, blister Delamination, which is referred to as, often occurs.

[0005]

The present invention is suitable for the production of printed wiring boards, particularly copper-clad epoxy resin laminates used for multilayer boards, and has good impregnability into glass cloth and heat resistance, It is intended to provide an epoxy resin composition which gives a cured product having excellent blister resistance and adhesion to a copper foil.

[0006]

The inventors of the present invention have conducted various studies to solve the above-mentioned problems and found that a composition using a specific epoxy resin can achieve its purpose. That is, the epoxy resin composition of the present invention is a composition comprising an epoxy resin, a curing agent, a curing accelerator and a solvent, wherein the epoxy resin is a mixture of a bisphenol (I) and a novolak resin (II) with epihalohydrin or methylepihalohydrin. An epoxy resin composition obtained by reacting an epoxy resin obtained by addition reaction and ring-closing reaction to form a glycidyl ether with halogenated bisphenols (III) with an onium salt or a base catalyst.

The bisphenols (I) used as the raw material of the epoxy resin in the present invention are bisphenols represented by the following general formula, and include bisphenol A, bisphenol F and bisphenol AD.

[Chemical 1] R ': a hydrocarbon group or hydrogen atom having 1 to 5 carbon atoms n: an integer of 0 to 4

It is preferable to use bisphenol A in which R is an isopropylidene group and R'is a hydrogen atom.

Novolak resin (II) used in the present invention
Is a condensate of formaldehyde and the above-mentioned bisphenols or phenols represented by the following general formula.
The softening point of the novolak resin of the present invention is preferably 110 ° C. or lower. More preferably, it is in the range of 30 ° C to 100 ° C. If the softening point is less than 30 ° C, the heat resistance of the cured product is insufficient, and if it exceeds 110 ° C, the high molecular weight increases,
In the reaction with halogenated bisphenols (III), a polymerizing reaction occurs and the impregnability into glass cloth deteriorates. The number average molecular weight is preferably 1000 to
300, more preferably 600 to 300, further preferably 600 to 350, preferably 2 or less, and more preferably 1.1 to 1.8. Here, the dispersity is the weight average molecular weight / number average molecular weight (Mw / Mn)
Means

[Chemical 2]

R ¹ and R ² are hydrogen atoms or have 1 to 1 carbon atoms.
It is a hydrocarbon group of 0 or less. The phenols condensed with formaldehyde are preferably phenol, O-cresol, para-t-octylphenol and P-cresol.

Bisphenols, which are likewise condensed with formaldehyde, have been mentioned above in the general formula. in this case,
Bisphenol A and bisphenol AD are preferred.

The number of functional groups in the novolak resin (II) is 2
The proportion of the above polynuclear component in the total phenolic components before the glycidylation reaction is preferably 3 to 50% by weight, more preferably 5 to 40% by weight. When the content of the polynuclear body is less than 3% by weight, the effect of increasing the glass transition temperature of the cured product of the epoxy resin composition is deteriorated.
If it exceeds 0% by weight, halogenated bisphenols (I
In the reaction with II), a polymerizing reaction occurs and the impregnation property into the glass cloth deteriorates.

(Glycidylation Step) Components (I), (I
The reaction of I) with epihalohydrin or methylepihalohydrin can be carried out by various methods following the conventionally known reaction. However, it is preferable to sequentially perform the etherification step and the dehydrohalogenation step because a stable glycidyl etherified epoxy resin (B) can be obtained. As epihalohydrin or methyl epihalohydrin, epichlorohydrin or 2
-Methylepichlorohydrin is preferred.

The etherification step is carried out by adding 0.1 to 1 equivalent of the phenolic hydroxyl group in the mixture of the components (I) and (II).
To 5 mol% of an etherification catalyst, for example, tertiary amines such as trimethylamine and triethylamine, tertiary phosphines such as triphenylphosphine and tributylphosphine, tetramethylammonium chloride, tetraethylbenzylammonium chloride, tetramethylammonium bromide, choline chloride and the like. The reaction is carried out in the presence of a quaternary ammonium salt, a quaternary phosphonium salt such as tetramethylphosphonium bromide and tetraphenylphosphonium bromide, and an inorganic base such as sodium hydroxide and potassium hydroxide.

In this etherification step, the reaction is carried out until at least about 50 mol%, preferably 70 mol% or more of the phenolic hydroxyl group is etherified. This reaction is generally carried out at a temperature of 60 to 110 ° C. under an inert atmosphere for 1 to 12 hours. The water content in the system at this time was 3.
It is preferably 0 wt% or less.

In the dehydrohalogenation step, dehydrochlorination is carried out under reduced pressure while azeotropically boiling the reaction mixture.
It is carried out under a reduced pressure of 100 mmHg to 500 mmHg in the range of ˜90 ° C. for about 1 to 6 hours. Usually, the reaction is terminated when the amount of residual hydrolyzable chlorine is 0.5 to 2.0 wt%. The weight ratio of bisphenols and novolac resin is
1-95 / 99-5, preferably 5-95 / 95-5,
More preferably, it is 10 to 90/90 to 10. When the amount of the novolac component is too large, a high molecular weight product is remarkably produced, impregnating ability of the cloth with the prepreg is deteriorated, and thermal shock resistance is deteriorated when the laminated plate is formed. If the novolac component is small, sufficient heat resistance cannot be obtained.

The glycidyl etherified epoxy resin (B) obtained by the above reaction has a softening point of 50 ° C. or lower, an epoxy equivalent of 170 to 220 and a halide content of 0.1% by weight.
It is the following.

The polyaddition reaction between the obtained glycidyl etherified epoxy resin (B) and the halogenated bisphenol (III) is carried out at 120 ° C. to 170 ° C. for 4 to 15 hours.
It is performed under an inert atmosphere. When using a catalyst, a quaternary ammonium salt, a quaternary sulfonium salt, or the like is used. The catalyst amount is preferably 10 to 300 ppm. When a solvent is used, toluene, xylene, cyclohexanone or the like is used. The solid content at that time is preferably 30% by weight or less.

The halogenated bisphenols (III) used in this polyaddition reaction are preferably brominated bisphenols, particularly tetrabromobisphenol A, tetrabromobisphenol F, 1,1-bis (3,5-dibromo-4). -Hydroxyphenyl) ethane is preferred.

Glycidyl etherified epoxy resin (B)
And the ratio of halogenated bisphenols are 74: 2
It is advisable to react at a ratio of 6 to 55:45. When the amount of halogenated bisphenols is large, the formation of high molecular weight compounds is remarkable,
Impregnating ability of the cloth when making the prepreg deteriorates. When the amount of halogenated bisphenols is small, it becomes impossible to have sufficient flame retardancy.

In the polyaddition reaction, in addition to the above essential components,
A general-purpose epoxy resin and / or an epoxy compound of a halogenated bisphenol may coexist. The epoxidized halogenated bisphenols can be obtained by glycidyl etherification of the aforementioned halogenated bisphenols (III) with epihalohydrin or methylepihalohydrin. When coexisting with the halogenated bisphenols (III), 0 to 15% by weight based on the total amount is obtained. When used at a ratio of 1, the coloring of the laminate by heating does not occur.

The epoxy resin composition of the present invention obtained by polyaddition reaction of the glycidyl etherified epoxy resin (B) with halogenated bisphenols as described above (hereinafter sometimes referred to as polyaddition reaction resin) is , Epoxy equivalent 350 to 500, Mn 500 to 1000, Mw / Mn
The ratio is 1.7 to 3.0, the amount of halide is 15 to 25, and the polyfunctional compound is 3 to 40%. Both the low molecular weight component and the high molecular weight component are small, and a viscous substance having a narrow molecular weight distribution is obtained.

Further, these compositions are treated with dicyandiamide,
A cured product obtained by curing with a curing agent such as a phenol type novolac resin has a Tg of 2 as compared with a cured product of a conventional composition obtained by blending these components without using a specific epoxy resin (B) or polyaddition reaction. It has a high -10 ° C and excellent blister resistance, and also has an excellent impregnation property of an uncured material into glass cloth.

In the epoxy resin composition of the present invention,
The specific glycidyl etherified epoxy resin is used, but this epoxy resin may be used alone as an epoxy resin, or other epoxy resin having two or more epoxy groups in one molecule. It is also possible to use together. Examples of other epoxy resins that can be used in combination include glycidyl ether type epoxy resins such as bisphenol A type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins, glycidyl ester epoxy resins, glycidyl amine type epoxy resins, and linear fats. Examples thereof include various polyfunctional epoxy resins such as group epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins and the like.
The amount of these other epoxy resins used in combination should be 50 parts by weight or less based on the total amount of the epoxy resin, that is, 100 parts by weight of the total amount of the epoxy resin and the other epoxy resin used in combination. If the amount of the other epoxy resin used in combination is too large, the properties of the composition of the present invention are impaired.

The curing agent used in the epoxy resin composition of the present invention is, for example, aromatic polyamine, dicyandiamide,
Examples thereof include acid anhydrides and various phenol type novolac resins.

Various curing accelerators can be used in the epoxy resin composition of the present invention. Examples thereof include benzyldimethylamine, amines such as various imidazole compounds, and tertiary phosphines such as triphenylphosphine.

Various solvents can be used as the solvent for the epoxy resin composition of the present invention. For example, acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N, N-dimethylformamide,
Examples thereof include N, N-dimethylacetamide, methanol and ethanol, and these solvents can be appropriately used as a mixed solvent of two or more kinds.

The epoxy resin composition of the present invention may further contain various other additives such as flame retardants and fillers, if necessary.

Production of a copper-clad epoxy resin laminate, for example, using the epoxy resin composition of the present invention can be carried out by a conventional method. For example, this epoxy resin composition is dissolved in a solvent to form a varnish, which is impregnated and applied to a reinforcing material such as glass cloth, and then dried by heating to remove the solvent to form a prepreg, and one or more prepregs are laminated. Layer copper foil on one or both sides of the object,
Then, heating and pressurization are carried out according to a conventional method to form a laminate.

[0030]

EXAMPLES Examples of the present invention will be described below. Synthesis Example of Novolac Resin Synthesis Example 1 A 1 L separable flask equipped with a cooler, a thermometer, a stirrer, and a dropping container was charged with 456 g of bisphenol A and 335 g of toluene, and the temperature was raised with stirring. When the temperature in the flask reached 70 ° C., 2.52 g of oxalic acid dihydrate as a catalyst was added. 37% formalin aqueous solution at 90 ℃ 1
30 g was added dropwise over 2 hours. The stirring was continued for another hour under reflux. Water and toluene were removed from the system while raising the temperature. After reaching 150 ° C., the mixture was concentrated at atmospheric pressure for 1 hour, then decompressed and concentrated at 20 mmHg and 150 ° C. for 1 hour to obtain a novolak resin (1). The softening point of the obtained resin was measured by an automatic softening point measuring device manufactured by METTLER CORPORATION, and the residual bisphenol A monomer and the molecular weight contained in the resin were measured by gel permeation chromatography (GPC). The separation column at this time was such that the amount of residual bisphenol monomer was 2 for Shim-pack-HSG10, 15,
20 (manufactured by Shimadzu Corporation), each with a molecular weight of HSG-2
0, 40, 50 and 60 were connected in series, and tetrahydrofuran was used as an eluent. Further, the novolac resins (2) to (4) were synthesized in the same manner as in Synthesis Example 1 with the charged amounts shown in Table 1.

[0031]

Synthetic Example of Glycidyl Etherified Epoxy Resin (Coglycidylation) Synthetic Example 5 A 2 L round bottom flask equipped with a thermometer, a stirrer, a separator, a cooler and a dropping container was used to synthesize the novolak resin (1 )
200 g and 1206 g of epichlorohydrin,
The temperature was raised to 90 ° C. with stirring. 30 g of water and 3 g of tetramethylammonium chloride were added at 90 ° C., and the mixture was stirred for 4 hours. Lower the temperature to 70 ° C and reduce the pressure to 500 mm
While maintaining Hg, 137 g of 48% sodium hydroxide solution was added from a dropping container over 3 hours. During this period, water was separated by a separator and removed outside the system. After dropping sodium hydroxide,
After dehydration for another 30 minutes, reduce the pressure to 20 mm.
Concentrated at 120 ° C. for 1 hour at Hg. After releasing the decompression, water 3
After adding 50 g and 250 g of toluene, the mixture was stirred at 90 ° C. for 30 minutes. After separating by standing to remove the water layer,
The mixture was concentrated at 0 mmHg and 150 ° C. for 1 hour to obtain 264 g of glycidyl etherified epoxy resin (5). The epoxy equivalent of the obtained resin was measured by the hydrochloric acid-dioxane method, the softening point was measured by an automatic softening point measuring device manufactured by METTLER CORPORATION, and the component ratio was measured by GPC as in the above novolak resin. Further, the epoxy resins (6) to (14) were synthesized in the same manner as in Synthesis Example 5 except that the charged amount was changed as shown in Table 2.

[0033]

[Table 1]

Synthesis Example of Polyaddition Reaction Resin Synthesis Example 15 Bisphenol A type epoxy resin (epoxy equivalent: 18) was placed in a 1 L separable flask equipped with a stirrer and a thermometer.
8) 171 g, glycidylated epoxy resin 5 of Synthesis Example 5
29.4 g, tetrabromobusphenol A 94.3
g was charged and the temperature was raised with stirring. When the temperature reached 100 ° C, 0.2% tetraethylammonium chloride was added.
g, and react at 160 ° C. for 5 hours to give a polyaddition reaction resin (1
5) was obtained. The epoxy equivalent of the obtained resin was the same as that described above, and the molecular weight was GPC (column: Simipac
k-HSG 20, 40, 50, 60 were connected in series). Further, the polyaddition reaction resins (16) to (24) are
Synthesis was carried out in the same manner as in Synthesis Example 15 with the charged amounts shown in Table 3. Further, polyaddition reaction resins (25), (26)
Was prepared in the same manner as in Synthesis Example 15 with the charged amounts shown in Table 3.

[0035]

[Table 2]

Table 3 Note * Bisphenol A type epoxy resin: Epoxy equivalent 18
8 g / eq ** Tetrabrom Bisphenol A Epoxy resin manufactured by Dainippon Ink and Chemicals, Inc. EPICLON 152-S Softening point 62 ° C Epoxy equivalent 364 g / eq Brom content 47.6 wt%

Examples 1 to 8 (Example 1) 25 g of 100 g of polyaddition reaction resin (19)
Example 2 was prepared by adding 2.5 g of dicyandiamide dissolved in 20 g of ethylene glycol monomethyl ether and 0.15 g of 2-ethyl-4 methylimidazole to a solution dissolved in 20 g of methyl ethyl ketone to prepare a varnish of an epoxy resin composition. A glass cloth (WEA-18W105F, manufactured by Nitto Boseki Co., Ltd.) was impregnated with this varnish and then dried in a drying oven at 140 ° C. for 6 minutes to prepare a prepreg, which was referred to as Example 1. The resin composition content of this prepreg was 49% by weight. The appearance of this prepreg was visually determined and set as Example 1. Further, the resin was kneaded from the prepreg, put in a mold with a thickness of 1 mm, and heat-cured at 170 ° C. for 1 hour to form a sheet, and the glass transition temperature Tg was measured with a Toyobo Co., Ltd. Rheorosolid at a heating rate of 2 ° C./min. . Further, four prepregs were laminated and press-molded at 170 ° C. for 1 hour under a pressure of 20 kg / cm ² to obtain a laminated plate. This laminate was allowed to stand in a ² kg / cm ² water bath at 121 ° C. for a certain period of time and then placed in a solder bath at 260 ° C. for 20 minutes.
After immersing for sec, the solder heat resistance after PCT was observed (○ plate has no swelling or peeling at all, Δ is slightly present, × is present). The following results are shown in Table 4. Further, instead of the polyaddition reaction resin (19), the polyaddition reaction resin (20) shown in Table 5 is used.
~ (26) in the same manner as in Example 1 to Example 2
8 varnish and prepreg. The same measurements as in Example 1 were carried out using the varnishes of Examples 2 to 8 and the prepreg, and the results are shown in Table 4.

[0038]

[Table 3]

Comparative Examples 1 to 7 Using the epoxy resins (5) to (8) shown in Table 2 and the polyaddition reaction resins (15) to (18) shown in Table 3 with the composition shown in Table 5, Example 1 Create an epoxy resin composition in the same manner as
As in Example 1, the varnishes of Comparative Examples 1 to 7 were used as the prepregs of Comparative Examples 1 to 7, respectively. Comparative Examples 1-7
The same measurements as in Example 1 were carried out using the varnish and the prepreg, and the results are shown in Table 5.

[0040]

[Table 4]

[0041]

The epoxy resin composition for laminates obtained by the polyaddition reaction using the specific co-glycidyl etherified epoxy resin of the present invention has good impregnability into glass cloth and the like, and heat resistance, It gives a cured product with excellent blister resistance and adhesion to copper foil.

Claims (7)

[Claims] 1. An epoxy resin (B) obtained by glycidyl etherification with epihalohydrin or methylepihalohydrin in the presence of a bisphenol (I) and a novolak resin (II) is further reacted with a halogenated bisphenol (III). An epoxy resin composition for laminated boards, which is obtained. 2. The reaction according to claim 1, further comprising (A)
The epoxy resin composition for laminates according to claim 1, wherein an epoxy resin and / or (D) an epoxidized product of a halogenated bisphenol are coexistent. 3. The novolak resin (II) has a softening point of 1
The epoxy resin composition for a laminate according to claim 1 or 2, which has a temperature of 10 ° C or lower, a number average molecular weight of 1,000 to 300, and a dispersity of 2 or lower. 4. The epoxy resin composition for laminates according to claim 1, wherein the weight ratio of the bisphenols to the novolac resin is 1 to 95:99 to 5. 5. The epoxy resin composition for a laminate according to claim 2, wherein the epoxidized halogenated bisphenol is 0 to 15% by weight. 6. A varnish containing the epoxy resin composition for laminates according to claim 1 and a solvent as main components. 7. A laminated plate obtained by impregnating a reinforcing material with the varnish according to claim 6.