JPH06298904A - Epoxy resin composition, epoxy resin mixture and its cured material - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition useful as a laminated material, etc., having excellent workability, heat resistance, toughness and water resistance, comprising a mixture of epoxy resins having specific structure and molecular weight distribution. CONSTITUTION:The composition comprises a mixture of epoxy resins of the formula n is integer not negative; R is H or bromine; X is H or glycidyl) wherein the average value of n of the mixture is >=0.3, the content of a component of n >=6 is <30wt.% and 10-95% of X in the mixture is glycidyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-viscosity epoxy resin composition capable of obtaining a cured product excellent in heat resistance, toughness and water resistance, an epoxy resin composition containing the same, and a cured product thereof. The composition of the present invention is extremely useful for a wide range of applications such as molding materials, casting materials, laminating materials, composite materials, paints, adhesives and resists.

[0002]

2. Description of the Related Art Epoxy resins, when cured with various curing agents, generally become cured products having excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc. It is used in a wide range of fields such as laminates, molding materials, and casting materials. Conventionally, the most industrially used epoxy resins include liquid and solid bisphenol A type epoxy resins obtained by reacting bisphenol A with epichlorohydrin. In addition, a flame-retardant solid epoxy resin obtained by reacting liquid bisphenol A type epoxy resin with Tetrabum bisphenol A is industrially used as a general-purpose epoxy resin.

[0003]

However, the general-purpose epoxy resin as described above increases in viscosity as the molecular weight increases, and the toughness of the cured product obtained by using it increases, but the heat resistance is It has the drawback of decreasing. Further, although a cured product obtained by mixing a polyfunctional epoxy resin such as cresol novolac epoxy resin in order to compensate for the decrease in heat resistance has high heat resistance,
The toughness is low and the water absorption is high. On the other hand, with the recent remarkable development of the electronic industry, etc., the heat resistance required for the electrical insulating materials used for these,
The toughness and water resistance are becoming more and more severe, and the advent of epoxy resins excellent in these properties is highly desired.

[0004]

In view of these circumstances, the inventors of the present invention have a low viscosity, and a cured product thereof has heat resistance,
As a result of intensive research for an epoxy resin composition having excellent toughness and water resistance, an epoxy resin composition having a specific structure and having a molecular weight distribution in a specific range has a low viscosity and excellent workability, The inventors have found that it imparts excellent heat resistance, toughness and water resistance to a cured product, and have completed the present invention.

That is, the present invention is based on the equation (1) (1)

[0006]

[Chemical 2]

(In the formula, n represents an integer of 0 or more. Each R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other. Further, each X is hydrogen. Which represents an atom or a glycidyl group, and each X may be the same or different from each other.), And the average value of n of the mixture is 0.3 or more. , And the content of the component in which n is 6 or more is less than 30% by weight, and the content of X in the mixture is 10 to 95.
% Is an glycidyl group, an epoxy resin composition,

(2) In an epoxy resin composition containing an epoxy resin and a curing agent, and optionally a curing accelerator,
An epoxy resin composition comprising the epoxy resin composition according to the above item (1) as the epoxy resin component, and (3) an epoxy resin for a laminate, comprising the epoxy resin composition according to the above item (2). Compound, (4) Above (2)
Alternatively, it relates to a cured product of the epoxy resin composition according to the item (3).

According to the present invention, the epoxy resin composition is
It is possible to obtain a cured product having extremely low viscosity and excellent heat resistance, toughness and water resistance. The epoxy resin composition of the present invention has, for example, the formula (2)

[0010]

[Chemical 3]

A mixture of epoxy resins represented by the formula (wherein R and n have the same meanings as described above), the average value of n in the mixture is 0.3 or more, and n is 6 or more. It can be obtained by reacting the alcoholic hydroxyl group of the mixture raw material in which the content of the component is less than 30% by weight with epihalohydrin.

This mixture raw material has, for example, the formula (3):

[0013]

[Chemical 4]

(Wherein R represents the same meaning as described above), and an epoxy compound represented by the formula (4)

[0015]

[Chemical 5]

The compound represented by the formula (wherein R has the same meaning as described above) at a specific ratio in the presence or absence of a solvent, triphenylphosphine, a quaternary ammonium salt, and NaOH. , And using a basic catalyst such as imidazoles, preferably at a temperature of 20 to 100 ° C.

In order to obtain the above mixture raw material in which the content of the component in which n is 6 or more is less than 30% by weight, the formula (3) is used.
It is necessary to adjust the use ratio of the epoxy compound of formula (4) and the compound of formula (4), and the epoxy compound 1 represented by formula (3)
The amount of the compound represented by the formula (4) is 0.05 to
It is preferable to use it in a range of 0.48 mol, particularly 0.1
It is preferably used in the range of 0.45 mol.

The method of epoxidizing the alcoholic hydroxyl group of the mixture raw material thus obtained is carried out by reacting the alcoholic hydroxyl group and epihalohydrin with dimethyl sulfoxide or a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinium. It can be carried out in the coexistence of non-alkali metal hydroxide.

According to the study of the present inventors, the alcoholic hydroxyl group of the mixture raw material is more reactive than general alcohols, and for example, dimethyl sulfoxide or quaternary ammonium salt or 1,3-dimethyl- Surprisingly, by allowing 2-imidazolidinone and an alkali metal hydroxide to coexist, the reaction between the alcoholic hydroxyl group and the epihalohydrin can be selectively carried out, and further the amount of the alkali metal hydroxide can be adjusted. According to the ability to epoxidize the alcoholic hydroxyl group of the mixture raw material to a desired ratio,
It was also found that the epoxidized product has a molecular weight distribution in a specific range, has an extremely low viscosity, and imparts excellent properties to the cured product.

The reaction between the alcoholic hydroxyl group of the mixture raw material and epihalohydrin can be carried out in the presence of dimethyl sulfoxide or a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone and an alkali metal hydroxide. it can. At that time, alcohols, aromatic hydrocarbons, ketones, cyclic compounds and ether compounds may be used in combination as the solvent. Dimethyl sulfoxide, quaternary ammonium salt, and 1,3-dimethyl-2-imidazolidinone may be used alone or in combination.

The amount of dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone used is preferably 5% by weight to 300% by weight with respect to the mixture raw material. If it is less than 5% by weight, the reaction between the hydroxyl group of the mixture raw material and epihalohydrin will be delayed, which requires a long reaction time, which is not preferable. On the other hand, if it exceeds 300% by weight, the effect of increasing the amount is almost eliminated and the volume efficiency is deteriorated, which is not preferable.

Examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride, etc. The amount of the quaternary ammonium salt is 0.3 to 1 equivalent of the hydroxyl group to be epoxidized in the raw material of the mixture. 50 g is preferred. 0.3 for 1 equivalent of hydroxyl group to be epoxidized
If it is less than g, the reaction between the hydroxyl group and the epihalohydrin is delayed, which requires a long reaction time, which is not preferable.
If it exceeds 0 g, the effect of increasing the amount is almost eliminated, but the cost becomes high, which is not preferable.

Examples of epihalohydrin include epichlorohydrin and epibromohydrin. The amount of epihalohydrin used is preferably 1 equivalent or more per 1 equivalent of the hydroxyl group to be epoxidized in the mixture raw material. However, if the amount exceeds 20 equivalents relative to 1 equivalent of the hydroxyl group to be epoxidized, the effect of increasing the amount will almost disappear and the volume efficiency will deteriorate, which is not preferable.

Alkali metal hydroxides include caustic soda.
Although caustic soda, caustic potash, lithium hydroxide, calcium hydroxide and the like can be used, caustic soda is preferred. The amount of the alkali metal hydroxide used is preferably 1 to 2.0 equivalents relative to 1 equivalent of the hydroxyl group to be epoxidized in the mixture raw material. The alkali metal hydroxide may be solid or aqueous solution. When an aqueous solution is used, the reaction can be carried out during the reaction while distilling the water in the reaction system out of the reaction system under normal pressure or reduced pressure.

The reaction temperature is preferably 20 to 100 ° C. If the reaction temperature is lower than 20 ° C, the reaction becomes slow and a long-time reaction is required. When the reaction temperature exceeds 100 ° C., many side reactions occur, which is not preferable.

In the epoxy resin composition of the present invention, n
Has an average value of 0.3 or more, preferably 0.4 to 2
And particularly preferably 0.5 to 1.7. Also n
The content of the component having a ratio of 6 or more is less than 30% by weight, preferably 28% by weight or less, and particularly preferably 26% by weight.
It is less than or equal to weight%.

In the epoxy resin composition of the present invention, X
10 to 95% are glycidyl groups, but 15 to 9 of X
5% is preferably a glycidyl group, especially 20 to
It is preferable that 95% is a glycidyl group. The epoxy resin composition of the present invention has a bromine content of 0 to 25% by weight.
Is preferable, and 0 to 20% by weight is particularly preferable.

The epoxy resin composition of the present invention will be described below. The epoxy resin composition of the present invention may be used alone or in combination with other known epoxy resins. The curing agent that can be used in the present invention includes various compounds such as amine compounds, acid anhydride compounds, amide compounds and phenol compounds, and is not particularly limited.
Specific examples include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromyl anhydride. Mellitic acid, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
Examples thereof include methyl nadic acid anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac, and modified products thereof, imidazole, BF ₃ -amine complex, guanidine derivative and the like. These curing agents may be used alone or in combination of two or more.

The amount of these curing agents used is preferably 0.7 to 1.2 equivalents relative to 1 equivalent of epoxy groups in the epoxy resin component. If the amount is less than 0.7 equivalent or more than 1.2 equivalent to 1 equivalent of epoxy group, curing may be incomplete and good cured physical properties may not be obtained.

When using the above-mentioned curing agent, a curing accelerator may be used in combination. Examples of the curing accelerator include imidazoles, tertiary amines, phenols, metal compounds and the like. The amount of these curing accelerators used is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the epoxy resin component. The epoxy resin composition of the present invention may further contain various compounding agents such as an inorganic or organic filler, if necessary.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the components. The epoxy resin composition of the present invention, a curing agent and, if necessary, a curing accelerator are mixed, the epoxy resin composition of the present invention can be easily cured by the same method as a conventionally known method to easily obtain a cured product of the epoxy resin composition. Can be obtained. For example, the epoxy resin composition of the present invention, a curing agent, and, if necessary, a filler and other additives are added, if necessary, in an extruder, a kneader, a roll, or the like.
To obtain an epoxy resin composition, which is sufficiently mixed with a resin or the like until melted, and the epoxy resin composition is melted and then molded using a casting machine or a transfer molding machine and further at 80 to 200 ° C. A cured product can be obtained by heating for ~ 6 hours. Further, the epoxy resin composition of the present invention is dissolved in a solvent, impregnated into a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. and heated and dried to obtain a prepreg by hot press molding. It is also possible to obtain a cured product.

[0032]

EXAMPLES The present invention will now be described in more detail with reference to Examples and Comparative Examples. In the following, all parts are parts by weight unless otherwise specified. The content of the component having n of 6 or more was measured by using standard gel permeation chromatography (GPC). The glass transition point, breaking energy and water absorption were measured according to JIS K-6911.

Examples 1-2 and Comparative Example 1 A bisphenol A type in which all R are hydrogen atoms as an epoxy compound represented by the formula (3) is placed in a round bottom flask equipped with a stirrer, a condenser and a thermometer. 372 parts of an epoxy compound (epoxy equivalent 186 g / eq), and bisphenol A (phenolic hydroxyl equivalent 114 g / eq) 9 in which all R are hydrogen atoms as the compound represented by the formula (4) 9
After 1 part was charged and heated to 140 ° C. for complete melt mixing, 0.37 part of triphenylphosphine as a catalyst was added and reacted at 140 ° C. for 60 minutes. The epoxy equivalent of the obtained resin composition (31) (raw material for the mixture) was 386 g.
It was / eq. The average value of n of the obtained resin composition (31) was 1.52 when calculated from the epoxy equivalent.
Further, the obtained resin composition (31) was dissolved in 1011 parts of epichlorohydrin, then 4.6 parts of tetramethylammonium chloride was added, and 98.5% NaOH 4 was added.
8.1 parts were added over 90 minutes. After reacting at 40 ° C. for 30 minutes, 150 parts of water was added and washed twice with water.
After the oil / water separation, epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain 514 parts of an epoxy resin composition (1) having an epoxy equivalent of 270 g / eq. The average value of n of the obtained epoxy resin composition was 1.5 when calculated from the epoxy equivalent.
2 and 71% of X is a glycidyl group, the content of the component having n of 6 or more is 25.2% by weight, the softening point is 58.8 ° C., and the melt viscosity at 150 ° C. is 1.7 ps. there were.

In the same manner, the amount of 98.5% NaOH used was adjusted to 37.0 parts to obtain 502 parts of an epoxy resin composition (2) having an epoxy equivalent of 290 g / eq. The obtained epoxy resin composition has an average value of n of 1.52 calculated from the epoxy equivalent, 54% of X is a glycidyl group, and the content of the component in which n is 6 or more is 24.7 wt. %, The softening point was 59.5 ° C., and the melt viscosity was 1.8 ps.

The obtained epoxy resin composition (1)-
(2) Using as a comparison the resin composition (31), phenol novolac as the curing agent, and triphenylphosphine (TPP) as the curing accelerator, compounded in the composition shown in Table 1, and kneading with a roll at 70 ° C. for 15 minutes. And 150 ° C, 180
After transfer molding for 2 seconds, the test piece was prepared by curing at 160 ° C. for 2 hours and then at 180 ° C. for 8 hours, and the glass transition point, breaking energy and water absorption were measured. The results are shown in Table 1. In addition, in the table, the numerical value in the column of formulation indicates part by weight.

[0036]

[Table 1] Table 1 Actual Examples Comparative Examples 1 2 1 Epoxy resin composition (1) 100 Epoxy resin composition (2) 100 Resin composition (31) 100 Epoxy equivalent (g / eq) 270 290 386 Epoxidation rate (%) (A) 71 54 0 Content of ingredients with n of 6 or more (%) 25.5 24.7 23.1 Melt viscosity (ps, 150 ° C) 1.7 1.8 2.1 Softening point (° C) 58.5 59.5 61.2 Phenol novolac 39 37 27 TPP 1 1 1 Glass transition point (℃) 158 149 104 Fracture energy (25 ℃, Kg / mm) 105 101 93 Water absorption rate (%) 1.35 1.41 2.30 (a) Indicates the ratio of X to a glycidyl group.

Examples 3 to 4 and Comparative Example 2 A bisphenol A type epoxy compound (wherein all R are hydrogen atoms) as the epoxy compound represented by the formula (3) in the round bottom flask used in Examples 1 and 2 ( Epoxy equivalent 186g
/ Eq) 372 parts, R as the compound represented by the formula (4)
All of which are bromine atoms, tetrabromobisphenol A
(Phenolic hydroxyl group equivalent 272 g / eq) 144 parts were charged, heated to 140 ° C. and completely melt-mixed, and then triphenylphosphine 0.37 part was added as a catalyst.
The reaction was carried out at 0 ° C for 60 minutes. Obtained resin composition (32)
The epoxy equivalent of (raw material of the mixture) was 351 g / eq. Further, the obtained resin composition (32) was dissolved in 946 parts of epichlorohydrin, 4.4 parts of tetramethylammonium chloride was added, and 98.5% NaO was added.
31.1 parts H3 was added over 90 minutes. 3 at 40 ° C
After reacting for 0 minutes, 80 parts of water was added and washed twice with water. After separating the oil and water, epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain 523 parts of an epoxy resin composition (3) having an epoxy equivalent of 286 g / eq. The average value of n of the obtained epoxy resin composition was 0.87 when calculated from the epoxy equivalent, 65% of X was a glycidyl group, and the content of the component in which n was 6 or more was 24.2% by weight. %,
The bromine content was 15.7% by weight and the softening point was 60.2 ° C.

In the same manner, the amount of 98.5% NaOH used was changed to 23.3 parts to obtain 517 parts of an epoxy resin composition (4) having an epoxy equivalent of 300 g / eq. The obtained epoxy resin composition has an average value of n of 0.87 calculated from the epoxy equivalent, 48% of X is a glycidyl group, and the content of the component in which n is 6 or more is 23.9 wt. %, Bromine content 15.9% by weight, softening point 62.2 ° C.
Met.

The obtained epoxy resin composition (3)-
(4) As a comparison, the resin composition (32) was dissolved in methyl ethyl ketone to prepare a solution having a resin concentration of 80% by weight. These resin composition solutions were mixed with dicyandiamide as a curing agent, 2MZ (2-methylimidazole) as a curing accelerator, methylcellosolve as a solvent, and dimethylformamide in a composition shown in Table 2 to form a varnish-like epoxy resin composition. Prepared. A glass cloth (WE-18K-BZ2, manufactured by Nitto Boseki Co., Ltd.) was impregnated with this composition and heated at 110 ° C. for 30 minutes to obtain a B-staged prepreg. This prepreg was stacked for 9 plies at 170 ° C.
Thickness of 1.5 under molding conditions of 40 Kgf / cm ² and 45 minutes
mm glass cloth laminated plate is made and JIS C-64
The glass transition point was measured in accordance with No. 81, and the measling resistance was also measured. The results are shown in Table 2. In addition, in the table, the numerical value in the column of formulation indicates part by weight.

[0040]

[Table 2] Table 2 Actual Examples Comparative Example 3 4 2 Epoxy resin composition (3) 80 Epoxy resin composition (4) 80 Resin composition (32) 80 Epoxy equivalent (g / eq) 286 300 351 Epoxidation rate (%) (B) 58 82 0 Content of components with n of 6 or more (%) 24.2 23.9 21.0 Softening point (° C) 60.2 62.2 71.0 Melt viscosity (ps, 150 ° C) 1.9 2.1 2.8 Dicyandiamide 3.4 3.4 3.4 2MZ 0.08 0.08 0.08 Methyl ethyl ketone 20 20 20 Methyl cellosolve 21 21 21 Dimethylformamide 21 21 21 Glass transition point (° C) 173 164 131 Measling resistance * ○ ○ × (b) Indicates the proportion of X being a glycidyl group. * Abnormal appearance after boiling in water for 1 hour and immersion in solder at 260 ° C for 20 seconds ○ ・ ・ ・ ・ No abnormality × ・ ・ ・ ・ Abnormality

[0041]

The epoxy resin composition of the present invention has a low viscosity and is excellent in workability, and a cured product obtained by using the composition has excellent heat resistance, toughness and water resistance. That is, the epoxy resin composition of the present invention can provide a cured product having excellent heat resistance, toughness, and water resistance, and can be used as a molding material, casting material, laminating material, paint, adhesive,
It is extremely useful for a wide range of applications such as resists.

Claims (4)

[Claims] 1. A formula (1): (In the formula, n represents an integer of 0 or more. Each R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other. Further, each X is a hydrogen atom or glycidyl. Group, each X may be the same or different from each other), and the average value of n in the mixture is 0.3 or more, and n The content of the component whose content is 6 or more is 30% by weight
And an epoxy resin composition characterized in that 10 to 95% of X in the mixture is a glycidyl group. 2. An epoxy resin composition containing an epoxy resin, a curing agent, and optionally a curing accelerator, wherein the epoxy resin composition according to claim 1 is contained as the epoxy resin component. object. 3. An epoxy resin composition for laminates comprising the epoxy resin composition according to claim 2. 4. A cured product of the epoxy resin composition according to claim 2.