JPH09316299A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition capable of exhibiting a lowered stress stress while retaining its flexural strength, toughness and heat resistance, comprising an epoxy resin, curing agent and an a-b type block copolymer composed of radical-polymerizable group-bearing polysiloxane(s) and a specific polymer segment. SOLUTION: This epoxy resin composition comprises (A) an epoxy resin (e.g. bisphenol A-type epoxy resin), (B) a curing agent (e.g. phenolic resin-based curing agent) and (C) an a-b type block copolymer composed of at least one kind of polysiloxane among those respectively bearing radical-polymerizable functional groups of formula I [(1) is an integer of 1-10; (m) is an integer of 1-30; (n) is an integer of 1-250; R1 is H or methyl; R2 is methyl, ethyl, phenyl or a group of formula II (R5 is H, phenyl or an alkyl; R6 is methyl, ethyl or phenyl; (n) is an integer of >=1); R3 is H, phenyl or an alkyl], formula III (R4 is the same kind as R6 ), etc., and a polymer segment made from a monomer of formula IV (R is H or methyl; (n) is an integer of 1-12) and another monomer bearing a group reactive with the epoxy resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive, a paint,
The present invention relates to an epoxy resin composition which is preferably used for civil engineering members, electric / electronic parts and the like. More specifically, the present invention relates to an epoxy resin composition which has a low stress, that is, an internal stress generated by curing shrinkage is relaxed, has high toughness, and has excellent mechanical properties and heat resistance.

[0002]

BACKGROUND OF THE INVENTION Epoxy resins are generally used in a wide range of fields such as adhesives, paints, civil engineering members, electric / electronic parts, etc. because of their excellent mechanical properties and heat resistance. Especially,
It is widely used as a highly reliable material for sealing and impregnating electric and electronic parts such as diodes, transistors, and integrated circuits.

However, with the recent miniaturization of electric and electronic parts, internal stress generated during curing has become a serious problem for the performance of products. For example, internal stress causes microcracks in the cured product, which damages the encapsulated product or reduces the mechanical properties or heat resistance of the product itself.

Such internal stress is usually proportional to the elastic modulus of the cured product. Therefore, a method of adding an elastomer to reduce the elastic modulus has been proposed. For example, an acrylonitrile-butadiene copolymer having good compatibility with an epoxy resin (eg, BF Goodrich “BF Goodrich”, trade name: Hiker “Hycar” CTBN) was added as a stress reducing agent. Epoxy resin compositions have been proposed [composite. Science. Technology "Comp.Sci.T
echnol. 31: 179 (1988)].

Further, in the field of semiconductor encapsulation, Japanese Patent Application Laid-Open No. 1-22
As disclosed in Japanese Patent No. 72622, attempts to blend modified silicone oil have been widely made.

[0006]

However, in the epoxy resin composition proposed in the former document, since the acrylonitrile-butadiene copolymer has too high compatibility with the epoxy resin, the characteristics of the epoxy resin itself are There is a problem of impairing certain mechanical properties and heat resistance.

Further, in the latter method disclosed in Japanese Patent Laid-Open No. 1-272622, the modified silicone oil bleeds on the surface of the molded article when the epoxy resin is cured, and the stress reducing effect is insufficient, and the mechanical strength is low. There is a problem in that the mechanical properties and heat resistance are reduced.

The present invention has been made by paying attention to the problems existing in the prior art as described above. It is an object of the invention to provide an epoxy resin composition capable of reducing stress while maintaining mechanical strength such as flexural strength and toughness and heat resistance of a cured epoxy resin. Another object is to provide an epoxy resin composition capable of suppressing bleeding of silicone oil during curing of the epoxy resin.

[0009]

In order to achieve the above object, the epoxy resin composition of the first invention comprises (A) an epoxy resin, (B) a curing agent and (C) an ab type block. (C) a-b type block copolymer comprising a polymer,
At least one of the polysiloxane having a radical-polymerizable functional group represented by the following general formula (1) and the polysiloxane having a radical-polymerizable functional group represented by the following general formula (3) and the following general formula ( 4) having a polymer moiety a formed of the monomer represented by 4) and a reactive group of the monomer represented by the general formula (4) and the epoxy resin, and having a radically polymerizable functional group. And a polymer portion b formed from the monomer contained therein.

[0010]

Embedded image[In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer from 1 to 250, R ₁Is hydrogen or a methyl group, R_TwoIs
Methyl group, ethyl group, phenyl group or the following general formula
(2),

[0011]

[Chemical 6] (In the formula, R ₅ is hydrogen, a phenyl group or C _{PH 2P + 1} , R ₆
Is a methyl group, an ethyl group or a phenyl group, n is an integer of 1 or more, and p is an integer of 1 to 10. ), R ₃ is hydrogen, a phenyl group or C _q H _{2q + 1} , R ₄ is a methyl group, an ethyl group or a phenyl group, and q is an integer of 1-10. ]

[0012]

[Chemical 7] [In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer of _{1 to} 250, R ₁ is hydrogen or a methyl group, R ₂ is a methyl group, an ethyl group, a phenyl group or the above general formula (2)].

[0013]

Embedded image (In the formula, R is hydrogen or a methyl group, and n is 1 to 12
Is an integer. The epoxy resin composition of the second invention is the epoxy resin composition of the first invention, further containing (D) a silicone oil.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. As the (A) epoxy resin,
Various types can be used, and the molecular structure, molecular weight and the like are not particularly limited as long as they have at least two epoxy bonds in the molecule. Examples of this epoxy resin include bisphenol A type epoxy resin, phenol novolac type epoxy resin, and cresol novolac type epoxy resin.

As the (B) curing agent, various types can be used, for example, phenol resin type curing agents such as phenol novolac resin and cresol novolac resin, diaminodiphenylmethane, diaminodiphenyl sulfone,
Examples thereof include amine-based curing agents such as metaphenylenediamine and acid anhydride-based curing agents such as methylcyclohexane 1,2 dicarboxylic acid anhydride, phthalic anhydride, and pyromellitic dianhydride. These are used alone or in combination of two or more. This curing agent is preferably added in a stoichiometric amount or more with respect to the epoxy groups of the epoxy resin (A).

Next, the polymer portion a of the (C) ab type block copolymer is a polysiloxane having a radical-polymerizable functional group represented by the following general formula (1) and the following general formula (3). ) And a random copolymer formed from at least one of polysiloxanes having a radically polymerizable functional group represented by the formula (4) and a monomer represented by the following general formula (4).

[0017]

Embedded image[In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer from 1 to 250, R ₁Is hydrogen or a methyl group, R_TwoIs
Methyl group, ethyl group, phenyl group or general formula (2),

[0018]

Embedded image (In the formula, R ₅ is hydrogen, a phenyl group or C _{PH 2P + 1} , R ₆
Is a methyl group, an ethyl group or a phenyl group, n is an integer of 1 or more, and p is an integer of 1 to 10. ), R ₃ is hydrogen, a phenyl group or C _q H _{2q + 1} , R ₄ is a methyl group, an ethyl group or a phenyl group, and q is an integer of 1-10. ]

[0019]

Embedded image[In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer from 1 to 250, R ₁Is hydrogen or a methyl group, R_TwoIs
Methyl group, ethyl group, phenyl group or the above general formula
(2)]

[0020]

[Chemical 12] (In the formula, R is hydrogen or a methyl group, and n is 1 to 12
Is an integer. When the polymer portion a is formed from the polysiloxane of the general formula (1) and the monomer of the general formula (4), the polysiloxane of the general formula (1) and the polysiloxane of the general formula (3) When formed from the monomer of general formula (4), it may be formed from the polysiloxane of general formula (3) and the monomer of general formula (4). Of these, the general formula (1)
The polysiloxane (1) has a double bond at both ends, and it is easy to introduce silicon into the block copolymer by polymerization. Therefore, it is preferable to contain the polysiloxane of the general formula (1).

The compound of the general formula (2) preferably has a number average molecular weight of 300 to 50,000. When the number average molecular weight is less than 300, the dispersion performance of the silicone oil is deteriorated, the silicone oil bleeds on the surface of the epoxy resin molded product, and the effect of reducing stress becomes insufficient. Further, the stress-reducing effect when the polysiloxane represented by the general formula (1) is used alone as the polysiloxane becomes insufficient. When the number average molecular weight is more than 50,000, the polysiloxane of the general formula (1) has poor polymerizability and is not suitable for practical use.

Examples of the (meth) acrylate represented by the general formula (4) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, hexyl (meth) acrylate, Examples thereof include lauryl (meth) acrylate.

Polymer portion a of ab type block copolymer
1 to 70% by weight is preferably at least one kind of the monomers represented by the general formulas (1) and (3). When the content of this monomer exceeds 70% by weight, the polymer portion a
The glass transition temperature of the epoxy resin becomes low, and the glass transition temperature of the epoxy resin after curing becomes low. In addition, when the ab type block copolymer is produced, the polymers are united with each other, and it is difficult to obtain an ab type block copolymer that can be substantially used. Further, when the content of the monomer is less than 1% by weight, the dispersion performance of the silicone oil is deteriorated, the silicone oil bleeds on the surface of the epoxy resin molded product, and the effect of reducing the stress becomes insufficient. In addition, the effect of lowering the stress becomes insufficient even when silicone oil is not used.

On the other hand, the polymer portion b of the ab type block copolymer has a radical-polymerizable functional group having a reactive group with the monomer represented by the general formula (4) and the epoxy resin. And a random copolymer formed from a monomer having

Polymer part b of ab type block copolymer
70 to 100% by weight is preferably a monomer represented by the general formula (4). When the content of the monomer represented by the general formula (4) is less than 70% by weight, the heat resistance of the epoxy resin cured product containing the ab type block copolymer is impaired.

Examples of the monomer having a radical-polymerizable functional group having a group reactive with an epoxy resin include (meth) acryl represented by the following general formula (5) or general formula (6). Examples thereof include glycidyl acid and (meth) acrylic acid.

[0027]

Embedded image

[0028]

Embedded image (In the general formula (5) or the general formula (6), R is hydrogen or a methyl group.) In the ab type block copolymer, a / b is a weight ratio of the polymer parts a and b. So 1/99 to 50/50
It is preferred that If this weight ratio is less than 1/99, the dispersion performance of the silicone oil becomes poor and the silicone oil bleeds on the surface of the epoxy resin molded product,
The effect of lowering the stress becomes insufficient. Further, the effect of lowering the stress when the block copolymer is used alone becomes insufficient. When the weight ratio exceeds 50/50, the softening temperature of the block copolymer becomes low and the polymer particles coalesce during drying or storage, which makes the handling of the polymer difficult, which is not suitable for practical use.

The weight average molecular weight (in terms of styrene, the same applies hereinafter) of the ab type block copolymer is usually 1
10,000 to 100,000 is preferable. When the weight average molecular weight is less than 10,000 or more than 100,000, the stress reducing effect is insufficient in both cases.

The ab type block copolymer is produced, for example, by a two-step polymerization method using a polymeric peroxide as a polymerization initiator. This two-stage polymerization method is disclosed in, for example, Japanese Patent Publication No. 60-3327 and Japanese Patent Publication No. 63-309.
This is the method disclosed in Japanese Patent Publication No. 56-56. In particular,
Either one of the monomers forming the polymer portion a or b is polymerized by the first stage polymerization reaction to synthesize a polymer having a peroxy bond in the molecule. Then, in the second stage polymerization reaction, the other monomer forming the polymer portion a or b is polymerized in the presence of the polymer having the peroxy bond to obtain a.
-A b-type block copolymer is produced. At this time, the polymer having a peroxy bond can be taken out as an intermediate from the reaction system and used for the second-stage polymerization reaction, or can be continuously used for the second-stage polymerization reaction without being taken out from the reaction system.

As the above-mentioned polymeric peroxide, for example, various ones represented by the following general formulas (7), (8) and (9) are used. One or more of these polymeric peroxides are used. In addition,
These polymeric peroxides are disclosed in JP-B-60-3.
It is described in Japanese Patent No. 327.

[0032]

Embedded image (In the formula, n represents an integer of 2 to 20)

[0033]

Embedded image (In the formula, n represents an integer of 2 to 20)

[0034]

Embedded image (In the formula, n represents an integer of 2 to 20) The amount of the polymeric peroxide used is 100 parts by weight of the monomer alone or the monomer mixture constituting the polymer part a or b used in the first-stage polymerization reaction. To 0.1-1
Parts by weight are preferred. When the amount is less than 0.1 part by weight, the amount of the remaining monomer is large, and when the amount is more than 1 part by weight, the molecular weight is low and the effect of reducing stress is poor. The polymerization temperature is 60 to 80 ° C., preferably 65 to 70 ° C. in the first stage polymerization reaction. When the temperature is lower than 60 ° C, the amount of residual monomers is large, and when the temperature is higher than 80 ° C, the molecular weight is low, and the effect of reducing stress is poor. The polymerization temperature in the second stage polymerization is 70 to 100 ° C, preferably 75 to 90 ° C.
It is. When the temperature is lower than 70 ° C, the polymerization rate becomes slow, and 1
When the temperature is higher than 00 ° C, it is difficult to adjust the polymerization rate. Further, the temperature of the second-stage polymerization is preferably higher than the temperature of the first-stage polymerization.

A chain transfer agent may be used for the purpose of adjusting the molecular weight during the production of the ab type block copolymer. As the chain transfer agent, various known ones are used. For example, n-dodecyl mercaptan, t-butyl mercaptan, n-butyl mercaptan, α-methyl styrene dimer [manufactured by NOF CORPORATION, trade name: NOFMER MSD] and the like can be mentioned. The amount of the chain transfer agent used is preferably 0.1 to 10% by weight based on the monomer. If it is less than 0.1% by weight, the effect of reducing the molecular weight is low, and if it exceeds 10% by weight, the polymerization time is prolonged and it is not suitable for practical use.

By the way, a homopolymer is by-produced during the production of the ab type block copolymer, but according to the two-step polymerization method,
The ratio of the net ab type block copolymer in all the polymers, that is, the block ratio is as high as 80% or more.
Therefore, when it is used as a stress reducing agent for epoxy resin, it can be used as it is without any particular purification.

As the polymerization method of the ab type block copolymer, any polymerization method such as a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method or a solution polymerization method can be adopted, but it is industrially pending. Most preferred is the turbid polymerization method.

The ab type block copolymer thus obtained is mixed with (A) an epoxy resin and (B) a curing agent and then cured. It is considered to have a so-called sea-island structure in which a block copolymer in which a polymer portion b is coordinated is dispersed around a. Moreover, the polymer portion b has good compatibility with the epoxy resin. For this reason, the internal stress caused by the curing shrinkage of the epoxy resin is absorbed and relaxed, and the effect of reducing the stress and excellent mechanical properties are obtained. Incidentally, while the solubility parameter (SP value) of the epoxy resin is about 10, the SP value of the polymer portion b is about 9.

Next, as (D) silicone oil,
Various commonly used ones are used and are not particularly limited. For example, dimethyl silicone oil, methylphenyl silicone oil, alkyl modified silicone oil, polyether epoxy modified silicone oil, RT
V silicone oil (trade name of Toray Dow Corning Silicone Co., Ltd.) and the like can be mentioned. These silicone oils are used alone or in combination of two or more and have a molecular structure,
The molecular weight is not particularly limited.

(C) ab type block copolymer and (D)
The blending amount of silicone oil is defined by the total amount of (C) and (D), and the total amount is 1 to 30 parts by weight based on 100 parts by weight of the total of (A) epoxy resin and (B) curing agent. preferable. If the total amount is less than 1 part by weight, the effect of lowering the stress is insufficient, and if it exceeds 30 parts by weight, the mechanical properties of the epoxy resin molded article deteriorate, which is not preferable. Further, the compounding ratio of the (C) a-b type block copolymer and the (D) silicone oil is (C) / (D) = 99 by weight ratio.
It is preferably / 1 to 5/95. If the compounding ratio of (C) is less than 5/95, the silicone oil bleeds and the low stress effect is insufficient, which is not preferable. (C)
Is more than 99/1, the mechanical properties of the epoxy resin molded product deteriorate, which is not preferable.

A known inorganic filler is used in the epoxy resin composition, if necessary. Examples of the inorganic filler include powders of aluminum hydroxide, crystalline silica, fused silica, calcium silicate, calcium carbonate, talc, barium sulfate, and the like, glass fibers, and the like. The compounding amount of the inorganic filler is preferably 100 to 1000 parts by weight based on 100 parts by weight of the total amount of (A) and (B). If the blending amount is less than 100 parts by weight, the moisture resistance, heat resistance, mechanical properties and moldability of the epoxy resin will be impaired, and 1000
If it exceeds the weight part, the moldability is poor and it is not suitable for practical use.

Various known additives are added to the epoxy resin composition, if necessary. Examples of the additive include waxes such as carnauba wax, release agents such as fatty acids such as stearic acid and metal salts thereof, colorants such as carbon black and red iron oxide, antimony oxide, and flame retardants such as halogenated compounds. Various additives such as a curing agent, a silane coupling agent, a curing accelerator such as benzylamine, and imidazole are appropriately mixed.

A method for molding a predetermined molded article using the epoxy resin composition is a usual casting method depending on the application,
A compression molding method, an injection molding method, a transfer molding method, an injection molding method, or the like can be used.

As described above, according to the embodiment, the following effects are exhibited. (1) In the cured product of the epoxy resin, the epoxy resin matrix has a sea-island structure in which the ab type block copolymer exists in a dispersed state, and the polymer portion b has good compatibility with the epoxy resin. Therefore, the internal stress generated due to the curing shrinkage of the epoxy resin is absorbed and relaxed, and the stress reduction can be achieved. (2) When the silicone oil is blended, the polymer portion a in the ab type block copolymer has compatibility with the silicone oil, so that the bleeding of the silicone oil during curing of the epoxy resin is effective. Can be suppressed. (3) Since the epoxy resin and the ab type block copolymer have a sea-island structure, and the polymer portion b has good compatibility with the epoxy resin, the epoxy resin cured product has excellent bending strength and toughness. The mechanical properties can be maintained. (4) Based on the sea-island structure of the epoxy resin and the ab type block copolymer and the heat resistance of the block copolymer itself,
Heat resistance can be maintained without lowering the glass transition temperature (Tg).

[0045]

EXAMPLES The present invention will be described more specifically below with reference to Synthesis Examples, Examples and Comparative Examples. In the examples, parts and% are parts by weight and% by weight, respectively, unless otherwise specified. The test method is the method described below. Abbreviations of compounds in Tables 1 and 2 represent the following compounds.

Polysiloxane-1: the general formula (1)
In the formula, l = 1, m = 1, n = 140, R ₁ = methyl group, R ₂ = R ₃ = R ₄ = methyl group monomer polysiloxane-2: In the general formula (1), 1
= 1, m = 1, n = 140, R ₁ = methyl group, R ₂ = R
₃ = R ₄ = Ethyl Group Monomer Polysiloxane-3: In the general formula (2), 1
= 1, m = 1, n = 10, R ₁ = methyl group, R ₂ = R ₃
= R ₄ = monomer polysiloxane methyl -4: In the general formula (2), l
= 1, m = 1, n = 10, R ₁ = methyl group, R ₂ = R ₃
= R ₄ = Ethyl group monomer MMA: Methyl methacrylate GMA: Glycidyl methacrylate MA: Methacrylic acid PMA: Propyl methacrylate HMA: Hexyl methacrylate Further, the test method is as follows. [Strain value] Strain gauge [Kyowa Denki Co., Ltd., product number: K
FG-5-120-C1-11L1M2R] diameter 36
It was fixed in a steel ring having a height of 5 mm and a height of 5 mm, and the inside was sealed with a silicone sealant to prepare a strain measuring device.
The device is placed in the center of a stainless steel container having a diameter of 75 mm and a height of 20 mm, and an epoxy resin composition of about 100 is placed around it.
g was cast, and the strain value after curing was measured. The larger the value, the lower the stress. [Bending Strength] and [Bending Elastic Modulus] The epoxy resin composition was cured by a casting method at 80 ° C. for 2 hours and then at 150 ° C. for 3 hours to obtain 80 mm × 10 mm × 4.
A mm cured product was prepared. Regarding this cured product, JIS
It was measured according to K6911. [Toughness value] 44mm × 10mm × 4mm
Prepare a cured product of
It was measured according to the three-point bending method based on TM E399. [Glass transition temperature (Tg)] Using a section of a cured product produced in the same manner as the above method, under an argon atmosphere, at 5 ° C /
It was measured by a differential calorimeter at a temperature rising rate of min. [Manufacture of Block Copolymer] (Synthesis Example 1) 68.8 parts of water in a stainless steel reactor equipped with a thermometer, a stirrer and a condenser, partially saponified polyvinyl alcohol [Nippon Kagaku Kogyo KK, trade name: Gohsenol] KH-17] 3 parts of 1% aqueous solution and 10% aqueous solution of tricalcium phosphate [Nippon Kagaku Kogyo KK, trade name:
3 parts of Super Tight 10] were charged as a suspension.

Next, 1 part of the polymeric peroxide represented by the general formula (7) and polysiloxane-11
0.0 parts, 10.0 parts of methyl methacrylate (MMA) and 0.1 parts of n-dodecyl mercaptan were charged into the above suspension and dispersed for about 30 minutes. Then, under nitrogen substitution,
Polymerization was carried out at 70 ° C. for 4 hours to complete the first stage polymerization.

Next, after cooling to room temperature, water 41 was added to the reactor.
2.5 parts, KH-17 17.6 parts, ST-10 1
7.6 parts, 70 parts of methyl methacrylate, 10 parts of glycidyl methacrylate (GMA) and 0.4 part of n-dodecyl mercaptan were added and impregnation operation was performed at room temperature for about 1 hour.
Then, under nitrogen substitution, the second stage polymerization was continued at 80 ° C. for 1 hour and then at 90 ° C. for 30 minutes. After cooling to room temperature to complete the polymerization operation, the obtained polymer was filtered and washed sufficiently with water. Next, it was pickled with hydrochloric acid and then sufficiently washed with water. Then, it was air-dried to obtain a white pearly a-b type block copolymer. (Synthesis Examples 2 to 10) White pearl was polymerized according to Synthesis Example 1 except that the charged amounts of polysiloxane-1, methyl methacrylate, glycidyl methacrylate and the chain transfer agent n-dodecyl mercaptan were changed as shown in Table 1. Ab
A mold block copolymer was obtained. (Synthesis Examples 11 to 13) Polymerization was performed according to Synthesis Example 1 except that polysiloxane-2, 3, and 4 were used in place of polysiloxane-1 in the first-stage polymerization, and white pearly a-
A b-type block copolymer was obtained. (Synthesis Example 14) Polysiloxane during the first-stage polymerization
Polymerization was carried out according to Synthesis Example 1 except that polysiloxanes-1 and 3 were used in combination in place of 1 to obtain a white pearly ab type block copolymer. (Synthesis Example 15) Polymerization was carried out according to Synthesis Example 1 except that propyl methacrylate was used instead of methyl methacrylate during the first-stage polymerization to obtain a white pearl-like ab type block copolymer. (Synthesis Example 16) Polymerization was performed according to Synthesis Example 1 except that hexyl methacrylate was used instead of methyl methacrylate in the second-stage polymerization to obtain a white pearly ab type block copolymer. (Synthesis Example 17) A white pearly a-b type block copolymer was obtained according to Synthesis Example 1 except that methacrylic acid was used instead of glycidyl methacrylate during the second-stage polymerization. (Synthesis Example 18) Polymerization was performed according to Synthesis Example 1 except that the type of the polymerization initiator was changed to the polymeric peroxide represented by the general formula (8) to obtain a white pearly ab type block copolymer. .

The above Synthesis Examples 1 to 9 are summarized in Table 1, and Synthesis Examples 10 to 18 are summarized in Table 2.

[0050]

[Table 1]

[0051]

[Table 2] [Production of Random Copolymer] (Synthesis Example 19) 400 parts of water in a stainless reactor equipped with a thermometer, a stirrer and a condenser, partially saponified polyvinyl alcohol [Nippon Kagaku Kogyo KK, trade name: Gohsenol KH- 20] and 15 parts of a 1% aqueous solution of tricalcium phosphate and 15 parts of a 10% aqueous solution of tricalcium phosphate (manufactured by Nippon Kagaku Kogyo Co., Ltd., trade name: Super Tight 10) were charged as a suspension.

After 0.3 part of benzoyl peroxide as a polymerization initiator was dispersed in the above suspension at room temperature for about 1 hour, 10 parts of polysiloxane-1, 80 parts of methyl methacrylate, 10 parts of glycidyl methacrylate and 0.5 part of n-dodecyl mercaptan was charged and the polymerization was continued at 80 ° C. for 4 hours and then at 90 ° C. for 30 minutes. After cooling to room temperature to complete the polymerization operation, the obtained polymer was separated by filtration.
Then, it was washed with acid, washed thoroughly with water, and air-dried to obtain a white pearl-like random copolymer. (Examples 1 to 16) Bisphenol A glycidyl ether type epoxy resin (epoxy equivalent; 190) [Yukaka Shell Epoxy Co., Ltd., trade name: Epicoat 828] 7
9.4 parts, diphenyldiaminomethane [Tokyo Kasei Co., Ltd.
Made, trade name: diphenyldiaminomethane] 20.6 parts,
Dimethyl silicone oil 16 parts, a- shown in the synthesis example
4 parts of b-type block copolymer was added, and the mixture was stirred at about 100 ° C. for 10 minutes. Then, it stirred for 30 minutes and obtained the epoxy resin composition. Using this, a cured product was prepared by the casting method, and the cured product was tested. The results are shown in Tables 3-6. (Example 17) An epoxy resin composition was obtained according to Example 1 except that the silicone oil used was changed to polyether epoxy modified silicone oil instead of dimethyl silicone oil. Using this, a cured product was prepared by the casting method described in Example 1, and the cured product was tested. Table 6 shows the results. (Examples 18 to 22) Epoxy resin compositions were obtained according to Example 1 except that the compounding amounts of the ab block copolymer and the silicone oil were changed as shown in Tables 6 and 7. Using this, a cured product was prepared by the casting method described in Example 1, and the cured product was tested. The results are shown in Tables 6 and 7. (Example 23) Bisphenol A glycidyl ether type epoxy resin (epoxy equivalent: 190) [Yukaka Shell Epoxy Co., Ltd., trade name: Epicoat 828] 55.6
Part, methylcyclohexene-1,2 dicarboxylic acid anhydride (Hitachi Chemical Co., Ltd., trade name: HN-2200) 44.4 parts,
Dimethyl silicone oil 16 parts, a- shown in the synthesis example
4 parts of b-type block copolymer was added, and the mixture was stirred at about 100 ° C. for 10 minutes. Then, it stirred for 30 minutes and obtained the epoxy resin composition. This was cured by a casting method at 100 ° C. for 2 hours and then at 150 ° C. for 16 hours to obtain a cured product.
The cured product was tested. The results are shown in Table 7. (Example 24) Phenolic novolac type epoxy resin (epoxy equivalent 220) 63.4 parts, phenol novolac resin (hydroxyl equivalent 110) 36.6 parts, triphenylphosphine 0.9 part, antimony trioxide 8.7 parts, carnauba 0.9 parts of wax, 540 parts of fused silica, 20 parts of silicone oil and 5 parts of an ab type block copolymer were added. The mixture was roll-kneaded at 70 to 100 ° C., cooled and pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was made into a tablet and a cured product was produced by a low-pressure transfer molding method. The cured product was tested. The results are shown in Table 7. (Example 25) An epoxy resin composition was obtained according to Example 23 except that aluminum hydroxide was used as the filler instead of fused silica. Using the epoxy resin composition, a cured product was produced by a low pressure transfer molding method. The cured product was tested. Table 7 shows the results.
It was shown to. (Comparative Examples 1 and 2) An epoxy resin composition was obtained according to Example 1 except that the compounding amounts of the ab block copolymer and the silicone oil were changed as shown in Table 8. Using this, a cured product was produced by the casting method described in Example 1. The cured product was tested. The results are shown in Table 8. (Comparative Example 3) An epoxy resin composition was obtained according to Example 1 except that the ab block copolymer was changed as shown in Table 8. Using this, a cured product was produced by the casting method described in Example 1. The cured product was tested. The results are shown in Table 8. (Comparative Example 4) An epoxy resin composition was obtained in the same manner as in Example 1 except that a random copolymer was used instead of the ab type block copolymer. Using this, a cured product was produced by the casting method described in Example 1. The cured product was tested. The results are shown in Table 8.

As for the types of silicone oil in Tables 3 to 8, 1 represents dimethylpolysiloxane and 2 represents polyether-epoxy-modified silicone oil.

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

[Table 5]

[0057]

[Table 6]

[0058]

[Table 7]

[0059]

[Table 8] As shown in Tables 3 to 8, in Examples 1 to 25,
Silicone oil and an ab type block copolymer are blended at a predetermined blending ratio to maintain a high strain value and reduce stress, that is, shrinkage during curing of an epoxy resin can be absorbed and relaxed. Moreover, it has excellent mechanical properties such as bending strength, bending elastic modulus, and toughness, and can maintain a high glass transition temperature (Tg) and heat resistance.

On the other hand, when the block copolymer is not blended (Comparative Examples 1 and 2) and the random copolymer is blended (Comparative Example 4), a polysiloxane having a radical-polymerizable functional group is used. When a non-block copolymer is used (Comparative Example 3), the strain value and mechanical properties such as bending strength, bending elastic modulus, toughness, and heat resistance are poor.

The technical idea understood from the above embodiment will be described below. (1) The content of the (C) ab type block copolymer is such that the total amount of the (A) epoxy resin and the (B) curing agent is 10
The epoxy resin composition according to claim 1, which is 1 to 30 parts by weight with respect to 0 parts by weight.

With this structure, it is possible to reduce stress during curing of the epoxy resin and to improve physical properties such as mechanical characteristics and heat resistance. (2) The (C) a-b type block copolymer and (D)
The total content of silicone oil is 1 to 3 relative to 100 parts by weight of the total amount of (A) epoxy resin and (B) curing agent.
The epoxy resin composition according to claim 2, which is 0 part by weight.

With this structure, it is possible to reduce the stress during curing of the epoxy resin while maintaining the physical properties such as mechanical characteristics and heat resistance. (3) The epoxy resin composition according to claim 1 or 2, wherein the proportion of the polymer portion b in the (C) a-b type block copolymer is the main component.

With this structure, physical properties such as stress reduction, mechanical properties and heat resistance can be exhibited in a well-balanced manner. (4) The polymer part a is formed from a polysiloxane having a radically polymerizable functional group represented by the general formula (1) and a monomer represented by the following general formula (4). The epoxy resin composition according to claim 1.

With such a constitution, silicon can be efficiently introduced into the block copolymer, and physical properties such as stress reduction, mechanical characteristics and heat resistance can be improved.

[0066]

As described above in detail, according to the present invention, the following excellent effects can be obtained. According to the epoxy resin composition of the first invention, it is possible to effectively reduce the stress, that is, the internal stress generated due to the curing shrinkage of the epoxy resin. Moreover, it is possible to maintain mechanical properties such as flexural strength and toughness and heat resistance of the cured epoxy resin.

According to the epoxy resin composition of the second invention, it is possible to suppress the bleeding of the silicone oil and to exert the stress reducing effect while maintaining the mechanical characteristics and the heat resistance.

Claims (2)

[Claims] 1. An epoxy resin (A), a curing agent (B), and
(C) ab type block copolymer, wherein (C) ab type block copolymer has the following general formula (1)
Polysiloxane having a radically polymerizable functional group represented by
Sun and radical-polymerizable resin represented by the following general formula (3)
At least one of polysiloxane having functional groups and
Polymer formed from the monomer represented by the general formula (4)
The reaction between the part a and the monomer and epoxy resin represented by the general formula (4)
Monomer having a reactive group and a radically polymerizable functional group
And a polymer portion b formed from
Epoxy resin composition. [Chemical 1][In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer from 1 to 250, R ₁Is hydrogen or a methyl group, R_TwoIs
Methyl group, ethyl group, phenyl group or the following general formula
(2), [Chemical formula 2](Where R_FiveIs hydrogen, a phenyl group or C_PH_{2P + 1}, R₆
Is a methyl group, an ethyl group or a phenyl group, and n is an integer of 1 or more.
The number and p are integers from 1 to 10. ), R_ThreeIs hydrogen, fe
Nyl group or C_qH_{2q + 1}And R_FourIs a methyl group, ethyl
A group or a phenyl group, and q is an integer of 1 to 10.
You. [Chemical formula 3][In the Formula, 1 is an integer of 1-10, m is an integer of 1-30, n
Is an integer from 1 to 250, R ₁Is hydrogen or a methyl group, R_TwoIs
Methyl group, ethyl group, phenyl group or the above general formula
(2)] [Chemical 4](In the formula, R is hydrogen or a methyl group, and n is 1 to 12
Is an integer. ) 2. The epoxy resin composition according to claim 1, further comprising (D) a silicone oil.