JPH0597972A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition capable of providing cured products, having high heat resistance and low hygroscopicity and excellent in low stress properties by blending a specific bisphenol type epoxy resin with a novolak type naphthol-based resin. CONSTITUTION:An epoxy resin composition is obtained by blending (A) a bisphenol type epoxy resin expressed by formula I [R<1> is 1-10C alkyl, phenyl or halogen; (m)is 0-4; (n) is 0-5 as the average value] with (B) a novolak type naphthol-based resin obtained by reacting naphthols expressed by formula II [R<2> is 1-10C alkyl, phenyl or halogen; (p) is 0-6; (q) is 1-3] with aldehydes or ketones. The amount of the component (A) in the whole epoxy resin is preferably >=50wt.%.

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 which gives a cured product having high heat resistance, low hygroscopicity and low stress.

[0002]

2. Description of the Related Art Epoxy resin compositions are used in various fields such as lamination, painting, adhesion, sealing and molding. In recent years, as the usage conditions of polymer materials have become severe,
The various properties required for polymer materials have become strict, and the epoxy resin compositions that are currently in general use cannot satisfy the required properties sufficiently.

For example, a curable epoxy resin composition using a phenol resin as a curing agent is used for encapsulating a semiconductor, but the required performance is becoming severe in this field as well. That is, as the degree of integration of semiconductor devices has increased, the size of semiconductor elements has increased significantly, and the packages themselves have become smaller and thinner.

Further, the mounting of semiconductors is also shifting to surface mounting. In surface mounting, when the semiconductor device is directly immersed in a solder bath and exposed to a high temperature, a large stress is applied to the entire package due to the expansion of moisture that has been absorbed, and a crack occurs in the sealing material. Therefore, a sealing material having good solder crack resistance is required to have high heat resistance, excellent low moisture absorption, and excellent stress resistance. And
The epoxy resin encapsulant mainly composed of cresol novolak type epoxy resin and phenol novolak type curing agent, which has been mainly used at present, has become insufficient in heat resistance, low hygroscopicity and stress resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to provide an epoxy resin composition capable of giving a cured product having high heat resistance, low hygroscopicity and low stress. is there.

[0006]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, use a biphenol type epoxy resin as an epoxy resin and contain a naphthol skeleton as a curing agent. The purpose could be achieved by blending a specific novolak type naphthol resin.

That is, the epoxy resin composition of the present invention comprises (a) the general formula

[Chemical 3]

(In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms, a phenyl group or a halogen atom, and m is 0 or 1
Is an integer of 4 to 4, each R ¹ and each m may be the same or different, and n is a number of 0 to 5 on average. ) A biphenol type epoxy resin represented by

[0009]

[Chemical 4]

(In the formula, R ² is an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a halogen atom, each R ² may be the same or different, and p is 0 or 1
Is an integer of 6 and q is an integer of 1 to 3. ) Is a composition comprising a novolak type naphthol resin obtained by reacting a naphthol represented by the formula (4) with an aldehyde or a ketone as an essential component.

The biphenol type epoxy resin represented by the general formula (a) used in the epoxy resin composition of the present invention is obtained by subjecting various biphenols and epihalohydrin to a condensation reaction in the presence of an alkali.

Examples of the biphenols as raw materials for producing the biphenol type epoxy resin include 4,4 '.
-Biphenol, 2,4'-Biphenol, 2,2'-
Biphenol, 3,3'-dimethyl-4,4'-biphenol, 3,5-dimethyl-4,4'-biphenol,
3,3'-dibutyl-4,4'-biphenol, 3,5
-Dibutyl-4,4'-biphenol, 3,3'-dibromo-4,4'-biphenol, 3,3 ', 5,5'-
Tetramethyl-4,4'-biphenol, 3,3'-dimethyl-5,5'-dibutyl-4,4'-biphenol, 3,3 ', 5,5'-tetrabutyl-4,4'-biphenol Can be given.

By reacting one or a mixture of two or more of these biphenols with epihalohydrin, the (a) biphenol type epoxy resin used in the present invention can be obtained. A typical embodiment of the production reaction will be described below.

First, biphenols are dissolved in an amount of 2 to 20 mol of epihalohydrin per mol of the phenolic hydroxyl group to form a uniform solution. Next, while stirring the solution, an alkali metal hydroxide in an amount of 1 to 2 mol per mol of the phenolic hydroxyl group is added as a solid or an aqueous solution and reacted.

This reaction can be carried out under normal pressure or under reduced pressure, and the reaction temperature is usually about 60 to 105 ° C. for the reaction under normal pressure and about 50 for the reaction under reduced pressure. ~ 80 ° C. The reaction is carried out by azeotroping the reaction solution while keeping a predetermined temperature as necessary, cooling the vaporized vapor, separating the resulting condensate into oil and water, and removing the water content into the reaction system. Dehydration is carried out from the reaction system depending on the returning method.
The addition of the alkali metal hydroxide is intermittently or continuously added little by little over 1 to 8 hours in order to suppress a rapid reaction. The total reaction time is usually about 1 to 10 hours.

After completion of the reaction, the insoluble by-product salt is removed by filtration or washed with water, and the unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy resin.

As epihalohydrin in this production reaction, epichlorohydrin or epibromohydrin is usually used, and as alkali metal hydroxide,
Usually NaOH or KOH is used.

In this production reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6- (trisdimethylaminomethyl) phenol. Catalysts such as imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; phosphines such as triphenylphosphine may be used.

Further, in this reaction, alcohols such as ethanol and isopropanol; acetone,
Ketones such as methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; inert organic solvents such as aprotic polar solvents such as dimethyl sulfoxide and dimethylformamide may be used.

Next, the (b) novolak type naphthol resin used as a curing agent in the epoxy resin composition of the present invention comprises an naphthol represented by the above general formula and an aldehyde or a ketone as an acidic catalyst. It is a novolak-type naphthol-based resin that has been subjected to a condensation reaction in the presence.

Examples of the naphthol represented by the above general formula as a raw material for producing the novolak type naphthol resin include 1-naphthol, 2-naphthol,
1-Bromo-2-naphthol, 6-chloro-2-naphthol, 4-methyl-1-naphthol, 3,5-dimethyl-2-naphthol, 1,6-dibromo-2-naphthol, 1,2-dihydroxynaphthalene , 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene,
1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,
7-dihydroxynaphthalene, 1,6-dihydroxy-
Examples thereof include 2-methylnaphthalene, 1-bromo-2,7-dihydroxynaphthalene, 1,3,6-trihydroxynaphthalene and the like.

Aldehydes and ketones to be condensed with these naphthols to obtain the novolak type naphthol resin used in the present invention include, for example, formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, glyoxal, croton. Examples thereof include aldehyde, terephthalaldehyde, acetone and cyclohexanone.

In the condensation reaction, one kind of naphthol may be used, or two or more kinds thereof may be used in combination.
Further, in some cases, other phenols may be used in combination for the reaction. The amount of the other phenols used in combination is preferably 50% by weight or less with respect to the entire mixture of the naphthols and the phenols. If the combined amount of other phenols is too large, the effect of the resin composition of the present invention cannot be sufficiently exhibited.

In the condensation reaction, the higher the ratio of the aldehydes or ketones to the naphthols used, the higher the molecular weight of the obtained novolak type naphthol resin, and the higher the heat resistance of the cured product of the resin composition. The resin composition has a high viscosity, and the handleability at the time of molding becomes poor. Therefore, depending on the intended use of the resin composition,
It is necessary to adjust the amount of aldehydes or ketones, but usually, the amount of aldehydes or ketones is 0.1 to 1.0 mol, preferably 0.2 per mol of naphthols.
~ 0.8 mol.

The condensation reaction is carried out in the presence of an acidic catalyst for 20
The reaction is carried out at a temperature of ~ 200 ° C for 1 to 20 hours. Examples of the acidic catalyst include mineral acids such as hydrochloric acid and sulfuric acid; oxalic acid,
Organic acids such as toluene sulfonic acid; other organic acid salts exhibiting acidity, and other acidic catalysts used for the production of ordinary novolak resin can be mentioned. The amount of the acidic catalyst used is 0.1 to 5 parts by weight based on 100 parts by weight of naphthols.

In the condensation reaction, an inert solvent such as aromatic hydrocarbons, alcohols and ethers can be used, and a ketone solvent can also be used depending on the selection of condensation reaction conditions. ..

Next, the epoxy resin composition of the present invention is a composition comprising the above-mentioned (a) biphenol type epoxy resin as an essential component of the epoxy resin.
Other epoxy resins can be used in combination with this epoxy resin. Other epoxy resins which can be used in combination include, for example, bisphenol A, bisphenol F, resorcin, hydroquinone, biphenol, tetramethylbiphenol, dihydroxynaphthalene, phenol novolak resin, cresol novolak resin, bisphenol A novolak. Obtained by condensation reaction of various phenols such as resin, dicyclopentadienephenol resin, terpenephenol resin, naphtholnovolak resin or various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde and glyoxal. Epoxy resin produced from various phenolic compounds such as polyvalent phenolic resin and epihalohydrin, and further diaminodiphenylmethane, aminophenol, and phenol Epoxy resins produced from a variety of amine compounds with an epihalohydrin, such as diamines.

The proportion of the (a) biphenol type epoxy resin in the total epoxy resin in the epoxy resin composition of the present invention is preferably 50% by weight or more. If the proportion of the (a) biphenol type epoxy resin is too small, the effects of the present invention (effects of giving a cured product having high heat resistance, low hygroscopicity and excellent stress resistance) cannot be sufficiently exerted.

The epoxy resin composition of the present invention is a composition prepared by blending the above-mentioned (b) novolak type naphthol resin as a curing agent. Can be used together.
Examples of other epoxy resin curing agents that can be used in combination include various phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, dicyclopentadiene phenol resin, and terpene phenol resin, or Various phenolic resins such as polyhydric phenolic resins obtained by condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal; tetrahydrophthalic anhydride, acid anhydride such as pyromellitic anhydride Substances; amines such as diaminodiphenylmethane, diaminodiphenylsulfone and the like can be mentioned. The amount of the other curing agent that can be used in combination is preferably 50% by weight or less based on the total amount of the curing agent. If the amount of the other curing agent used is too large, the effects of the present invention cannot be sufficiently exhibited.

In the epoxy resin composition of the present invention, if necessary, a curing accelerator, a filler, a coupling agent, a flame retardant,
A plasticizer, a solvent, a reactive diluent, a pigment and the like can be appropriately added.

Examples of the curing accelerator include imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole; amines such as 2,4,6-tris (dimethylaminomethyl) phenol and benzyldimethylamine. An organic phosphorus compound such as tributylphosphine, tris (dimethoxyphenyl) phosphine, triphenylphosphine, and the like.

Examples of the filler include fused silica, crystalline silica, glass powder, alumina and zircon. Further, examples of the flame retardant include antimony trioxide, phosphoric acid, and the like, and the flame retardancy can also be achieved by using a part of the epoxy resin used as a brominated epoxy resin.

Since the epoxy resin composition of the present invention gives a cured product having high heat resistance, low hygroscopicity and low stress as compared with the conventional epoxy resin composition, sealing,
It can be advantageously used in fields such as lamination and painting.

[0034]

[Examples] Hereinafter, a biphenol type epoxy resin production example, a novolak type naphthol resin production example, an example, and a comparative example will be described in more detail.

Production Example 1 of Biphenol-type Epoxy Resin Content of 3000 ml equipped with a thermometer, stirrer and cooling pipe
In a three-necked flask of No. 3, 242 g of 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol, 1295 g of epichlorohydrin, and 504 g of isopropyl alcohol.
Was charged, and the temperature was raised to 35 ° C. to dissolve uniformly, and then 4
190 g of 8.5 wt% sodium hydroxide aqueous solution was added dropwise over 1 hour. During that time, the temperature was gradually raised so that the temperature inside the system became 65 ° C. at the end of the dropping. Then, the reaction was carried out by holding at 65 ° C. for 30 minutes. After that reaction,
It was washed with water to remove the by-product salt and excess sodium hydroxide. Then, excess epichlorohydrin and isopropyl alcohol were distilled off from the product under reduced pressure to obtain a crude epoxy resin.

This crude epoxy resin was dissolved in 500 g of methyl isobutyl ketone, 6 g of a 48.5% by weight sodium hydroxide aqueous solution was added, and the mixture was reacted at a temperature of 65 ° C. for 1 hour. After the reaction was completed, sodium phosphate monobasic was added to neutralize excess sodium hydroxide, and the product was washed with water to remove by-product salts. Then, methyl isobutyl ketone was completely removed under reduced pressure to obtain a tetramethylbiphenol type epoxy resin.

This epoxy resin has an epoxy equivalent of 185
g / eq. , A yellow solid having a melting point of 108 ° C., and the value of n in the above general formula was 0.09.

Production Example 2 of Biphenol Epoxy Resin 3,3 ', 5,5'-Tetramethyl-used in Production Example 1
Instead of 242 g of 4,4'-biphenol, 4,4'-
186 g of biphenol were reacted with epichlorohydrin in the same manner as in Preparation Example 1 and post-treated to give an epoxy equivalent of 160 g / eq. A biphenol type epoxy resin having a melting point of 151 ° C. was produced. The value of n in the above general formula of this epoxy resin was 0.15.

Novolac-type naphthol resin production example 1 Internal volume of 3000 ml equipped with thermometer, stirrer and cooling pipe
1152 g of α-naphthol, 600 g of methyl isobutyl ketone, and 20 g of p-toluenesulfonic acid were charged into the three-necked flask described in (1), and the temperature was raised to 80 ° C. to uniformly dissolve them. Next, 400g of 36% aqueous formaldehyde solution
Was added dropwise over 1 hour while maintaining the internal temperature of the solution at 80 ° C. Then, the mixture was kept at 100 ° C. for 3 hours for reaction. Then, after washing with water to remove p-toluenesulfonic acid, water, methyl isobutyl ketone, and unreacted α-naphthol were distilled off while gradually raising the temperature, and finally 1
Water, methyl isobutyl ketone, and unreacted α-naphthol were completely removed by keeping at 60 ° C. under reduced pressure of 1 mmHg for 3 hours to obtain α-naphthol novolak resin. This naphthol novolac resin has a hydroxyl equivalent of 152 g / e.
q. The softening point was 108 ° C.

Production Example 2 of Novolac-type naphthol resin In place of 1152 g of α-naphthol used in Production Example 1,
Using 1440 g of 1,6-dihydroxynaphthalene,
Otherwise, react with formaldehyde in the same manner as in Production Example 1, and carry out the same post-treatment to give a hydroxyl equivalent of 87 g /
eq. A dihydroxynaphthalene novolak resin having a softening point of 114 ° C. was obtained.

Novolac-type naphthol-based resin Production Example 3 400% 36% aqueous formaldehyde solution used in Production Example 1
Instead of g, salicylaldehyde 488 g was used, otherwise the reaction was carried out with α-naphthol in the same manner as in Production Example 1, and the same post-treatment was carried out to give a hydroxyl equivalent of 133 g /
eq. Thus, α-naphthol salicylaldehyde novolak resin having a softening point of 135 ° C. was obtained.

Examples 1 to 4 Comparative Examples 1 to 3 As shown in Tables 1 and 2, each of the biphenol type epoxy resins obtained in Production Examples 1 and 2 of biphenol type epoxy resin as an epoxy resin, or orthocresol novo Each of the rack type epoxy resins is used, and each of the novolak type naphthol resins obtained in Production Examples 1 to 3 of the novolak type naphthol resin as a curing agent, or each of the phenol novolak resins is used as a curing agent, and a brominated epoxy resin is used as a flame retardant. Each of the epoxy resin compositions was formulated by using antimony trioxide, triphenylphosphine as a curing accelerator, silica powder as a filler, epoxysilane as a surface treatment agent, and carnauba wax as a release agent.

Next, each of the obtained blends was melt-mixed for 5 minutes at a temperature of 80 to 130 ° C. using a mixing roll. Each of the obtained molten mixtures was taken out as a sheet and pulverized to obtain each molding material.

Using each of these molding materials, molding was carried out by a low pressure transfer molding machine at a mold temperature of 180 ° C. for a molding time of 180 seconds to obtain a glass transition temperature measuring test piece, a moisture absorption measuring test piece, and a simulated element. To obtain 44-pin FPP (flat plastic package) sealed at 180 ° C.
I was allowed to post cure for 8 hours.

The glass transition temperature after the post cure,
The results of testing the moisture absorption rate and the solder heat resistance are as shown in Table 1 and Table 2, respectively. Each of the molding materials of Examples 1 to 4 gives a cured product having a high glass transition temperature, a low moisture absorption rate and excellent solder heat resistance as compared with the molding materials of Comparative Examples 1 to 3. In particular, the excellent heat resistance of the solder is considered to be due to the effect of giving a cured product excellent in low hygroscopicity, high glass transition temperature and low stress,
This shows that it is suitable for semiconductor encapsulation.

[0046]

[Table 1]

[0047]

[Table 2]

Note to Tables 1 and 2: * 1 ... Yukaka Shell Epoxy Co., Ltd. trade name Epicoat 180H65, epoxy equivalent 201, softening point 67 ° C. * 2 ... Yuka Shell Cepoxy Co. trade name Epicoat 5050 , Epoxy equivalent 385, bromine content 49% by weight * 3 ... Gunei Chemical Co., Ltd., softening point 85 ° C. * 4 ... Tatsumori company trade name RD-8 * 5 ... Shin-Etsu Chemical Co., Ltd. product Name KBM-403 * 6 ... Determined from the transition point of the thermal expansion curve using TMA * 7 ... Moisture absorption rate after 168 hours of moisture absorption in air at 85 ° C. and 85% RH * 8 ... After absorbing 16 pieces of 44-pin FPP in air at 85 ° C. and 85% RH for 168 hours, the pieces were immersed in a solder bath at 260 ° C. for 10 seconds to determine the number of cracks.

[0049]

The epoxy resin composition of the present invention can give a cured product having excellent balance of heat resistance, low hygroscopicity and low stress.

Claims (1)

[Claims] 1. (a) General formula: (In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms, a phenyl group or a halogen atom, m is 0 or an integer of 1 to 4, each R ¹ and each m are the same as each other, May be different, and n is an average value of a number from 0 to 5), and (b) a general formula (In the formula, R ² is an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a halogen atom, each R ² may be the same or different, and p is 0 or an integer of 1 to 6. And q is an integer of 1 to 3.) An epoxy resin composition obtained by blending a novolak type naphthol resin obtained by reacting a naphthol represented by the formula (1) with an aldehyde or a ketone as an essential component. ..