JP3073033B2 - Epoxy resin composition - Google Patents

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 and, more particularly, to an epoxy resin composition having excellent heat resistance and toughness suitable for various moldings such as a laminate.

[0002]

2. Description of the Related Art Epoxy resins have excellent thermal, mechanical and electrical properties and are used in various fields such as adhesives, paints, electric / electronic materials, civil engineering materials and the like.

[0003] However, as the application of epoxy resins spreads to advanced technical fields such as high-performance composite materials and electronic materials, higher-performance resins are required. In particular, improvements in heat resistance and toughness of cured resins have been required.

As a technique for improving the toughness of a cured resin, a method of adding a rubber-based modifier such as carboxy-terminated acrylonitrile-butadiene rubber (CTBN) (Journal of Materials Science, Vol. 21, 246)
2) or a method using an engineering resin such as polysulfone or polyetherketone as a reinforcing agent (Polym.Bu
ll. 13 , 201 (1985), ACS Polym Preprints. 29 (1), 363 ('8
8)) has been proposed.

[0005] However, the method of adding a rubber-based modifier can improve the toughness but has a problem that the heat resistance of the cured resin is reduced. On the other hand, a method using an engineering resin as a reinforcing agent can prevent a decrease in heat resistance, but is not satisfactory in toughness.

As a technique for improving the heat resistance of a cured resin, a method using a styrene-maleic anhydride-amino-modified N-substituted maleimide copolymer as a latent curing agent (JP-A-1-304112) is disclosed. ing. However, in this method, when the molecular weight of the copolymer used as the curing agent is increased, the storage stability of the mixture with the epoxy resin is reduced, or the curing speed is reduced, so that sufficient toughness can be imparted. Did not.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art. Accordingly, an object of the present invention is to provide an epoxy resin composition having excellent heat resistance and toughness.

[0008]

The present invention relates to an epoxy resin (A) and 10 to 90 mol% of a structural unit (a) represented by the following formula (1).
And 10 to 90 mol% of the structural unit (b) represented by Chemical formula 2
(However, the total of the structural units (a) and (b) is 100 mol%) and a copolymer (B).

[0009]

Embedded image (Wherein, R ₁ is water Motoma other is a methyl group, R ₂ is water
A hydrogen atom, an aliphatic saturated or unsaturated hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an acetyl group, a carboxylate group, an amide group, an alkoxy group or a cyano group. )

[0010]

Embedded image (Wherein, R ₃ and R ₄ are each independently hydrogen, halogen or a methyl group, R ₅ is hydrogen, halogen, alkyl, Ru Oh <br/> cycloalkyl group or an aryl group.)

[0011]

The epoxy resin (A) used in the present invention is not particularly limited. For example, Epicoat 828, Epicoat 1001 (manufactured by Yuka Shell Epoxy), AER-33
Liquid or solid bisphenol A type epoxy resin such as 1 (manufactured by Asahi Kasei Corporation), ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH-434 (manufactured by Toto Kasei Co., Ltd.), MY-720
Glycidylamine type epoxy resin such as (Ciba-Geigy), bisphenol F type epoxy resin such as Epicron 830 (Dai Nippon Ink and Chemicals), phenol such as Epicoat 152 and Epicoat 154 (Yuika Shell Epoxy). Novolak type epoxy resin,
Brominated bisphenol A type epoxy resin such as Epiclon 152 (manufactured by Dainippon Ink and Chemicals, Inc.), ESCM
-220 (manufactured by Sumitomo Chemical Co., Ltd.), cresol novolak type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin and the like.

These epoxy resins can be used alone or
It can be used as a mixture of more than one species. Considering the ease of mixing when used by mixing with the copolymer (B), a low-viscosity liquid such as Epicoat 828 or AER-
Preferred is a bisphenol A type epoxy resin such as 331.

The copolymer (B) used in the present invention has the structural unit (a) represented by the above formula (1) and the structural unit (b) represented by the following formula (2). Such a copolymer
The method for producing (B) is not particularly limited. For example, the monomer (I) which gives the structural unit (a) by polymerization and the structural unit (b)
Can be produced by radical copolymerization with the monomer (II) giving In addition, the structural unit
(b) A precursor copolymer capable of forming (b) is synthesized by radical copolymerization and then subjected to imide modification to obtain a copolymer.
The method (B) can also be adopted.

Examples of the precursor copolymer used in the latter method include a maleic anhydride group-containing copolymer such as a styrene-maleic anhydride copolymer.

[0015] As the monomer (I) used in making the copolymer (B) in the former method, for example, ethylene, propylene, 1-butene, isobutylene, cyclopentene, olefin cyclohexene, vinyl acetic acid fatty acid vinyl esters and the like; styrene, alpha-methyl styrene, vinyl toluene, aromatic vinyl compounds such as t- butyl styrene; vinyl; butadiene, isoprene emissions
Conjugated dienes such as; acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, decyl acrylate, octadecyl acrylate, and methoxyethyl acrylate; methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate; Methacrylic acid esters such as octadecyl methacrylate and methoxyethyl methacrylate; unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; acrylamide; and one or more of these can be used.

In particular, an aromatic vinyl compound is preferable because it can reduce the water absorption of the obtained cured resin and also has excellent heat resistance.

As the monomer (II), a monomer giving the structural unit (b) can be used without limitation. For example, maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-propyl maleimide, N- cyclohexyl maleimide, there are N- Feniruma <br/> Reimi de like, may be used singly or in combination.

The structural unit (b) having an imide group not only imparts heat resistance to the copolymer (B) but also has an effect of improving compatibility with the epoxy resin.

The ratio of the structural unit (a) and the structural unit (b) in the copolymer (B) is in the range of 10 to 90 mol% of the structural unit (a) and 10 to 90 mol% of the structural unit (b). is there. Copolymer
If the proportion of the structural unit (a) in (B) is less than 10 mol%, the toughness of the cured resin will be insufficient, and if it exceeds 90 mol%, the heat resistance of the cured resin will be undesirably reduced.

The average molecular weight of the copolymer (B) used in the present invention is preferably in the range of 10,000 to 1,000,000. Copolymer
If the average molecular weight of (B) is less than 10,000, the toughness of the cured resin becomes insufficient, and if it exceeds 1,000,000, mixing with the epoxy resin becomes difficult, which is not preferable.

The glass transition temperature of the copolymer (B) is 1
It is preferably at least 00 ° C. If the temperature is lower than 100 ° C., the heat resistance of the obtained cured resin is insufficient. Therefore, it is preferable to select the monomer (I) which gives the structural unit (a) so that the glass transition temperature does not become lower than 100 ° C.

In the present invention, it is necessary to contain the structural unit (a) and the structural unit (b) in a specific ratio as the structural units constituting the copolymer (B), but the effects of the present invention are impaired. A small amount of other structural units may be contained in the copolymer (B). However, a structural unit having a functional group that easily reacts with the epoxy group in the epoxy resin such as an acid anhydride group may impair the effect of increasing the toughness of the cured resin, so that care must be taken in its formulation.

The epoxy resin composition of the present invention contains an epoxy resin (A) and a copolymer (B). The mixing ratio of these components is as follows.
The proportion of the copolymer (B) is preferably 1 to 30% by weight based on the weight%. When the proportion of the copolymer (B) is less than 1% by weight, the toughness and heat resistance of the cured resin become insufficient. Also, copolymer
If the proportion of (B) is more than 30% by weight, the epoxy resin composition tends to undergo phase separation or the curing speed becomes slow, which may cause problems in curability and workability,
Further, the mechanical or electrical properties inherent to the epoxy resin are undesirably deteriorated from the cured resin.

The resin composition of the present invention comprises an epoxy resin (A)
And a copolymer (B) as an essential component, but if necessary, a known epoxy resin curing agent or curing accelerator, a filler, a flame retardant, a reinforcing agent, a surface treatment agent, a pigment, etc. are used in combination. be able to.

Known epoxy resin curing agents include amine-based curing agents such as aromatic amines such as metaxylenediamine and diaminodiphenylsulfone and aliphatic amines such as diethylenetriamine, acid anhydrides, dicyandiacid, hydrazide compounds, polyphenols, polyphenols and the like. Mercaptan and the like.

The method of mixing each component in the present invention is not particularly limited, and a preferable method can be appropriately selected depending on the properties of each component and the mixing state of the desired composition.

As an example of the mixing method, there is a method in which a homogeneous solution is obtained by using a solvent in which each component is dissolved, and the epoxy resin (A) and the copolymer (B) are heated at a relatively high temperature without using a solvent. And then a method of lowering the temperature and adding a curing agent.

The epoxy resin composition of the present invention obtained by mixing the components as described above can be made into a cured resin by a curing method similar to a conventionally known epoxy resin. For example, a method of impregnating the resin composition of the present invention into a sheet-like reinforcing material made of a fibrous base material, removing a solvent if necessary to prepare a prepreg, and heating and pressing this to form a laminated plate is adopted. be able to.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by these examples.

[0030]

Reference Example 1 200 g of N-phenylmaleimide, 100 g of styrene and 3000 g of benzene were charged into a three-necked flask equipped with a stirrer, a condenser and a thermometer, and then azobisisobutyronitrile was used as a polymerization initiator.
After adding 5 g and replacing with nitrogen, the polymerization reaction was continued at 60 ° C. for 3 hours. After completion of the reaction, the reaction solution was dissolved in N, N-dimethylformamide and then reprecipitated in methanol.
By drying under reduced pressure at 50 ° C., a copolymer (1) was obtained.

The composition of the copolymer (1) was determined by elemental analysis. As a result, it was found to be 46 mol% of styrene units and 54 mol% of N-phenylmaleimide units. The average molecular weight of copolymer (1) was 500,000 as determined by gel permeation chromatography using polystyrene as a standard.

[0032]

REFERENCE EXAMPLE 2 Except that 194 g of butyl acrylate, 82.5 g of vinylbenzyl glycidyl ether and 23.5 g of styrene were used instead of the monomers in Reference Example 1,
The procedure of Reference Example 1 was repeated to obtain a copolymer (2).

The composition of the obtained copolymer (2) was butyl acrylate / vinylbenzyl glycidyl ether / styrene = 62/22/16 (mol%), and the average molecular weight was 170,000.

[0034]

Example 1 83.7 g of an epoxy resin AER-331 (manufactured by Asahi Kasei Corporation) was heated to 140 ° C., and 9.3 g of the copolymer (1) obtained in Reference Example 1 was added thereto, followed by stirring for 80 minutes. And the copolymer (1) were dissolved in an epoxy resin to obtain an epoxy resin composition (1) of the present invention.

The obtained epoxy resin composition (1) was mixed with 120
After the temperature was adjusted to 2 ° C., 27.0 g of P, P′-diaminodiphenylsulfone (DDS) was added as a curing agent, and the mixture was stirred for 70 minutes. After the DDS is dissolved, it is poured into a silicone resin mold that has been
For 1 hour, and further heated at 180 ° C. for 5 hours to obtain a cured resin.

The obtained cured resin was molded with sandpaper, subjected to a bending test and a fracture toughness test, and the glass transition temperature was measured. Table 1 shows the obtained results. In addition, the measuring method of various physical properties is as follows.

(1) Bending test The bending test was performed at a crosshead speed of 2 mm / min using a three-point bending test piece (4 × 10 × 80 mm) in accordance with JIS K7203.

(2) Fracture Toughness Test The fracture toughness test is performed at a crosshead speed of 1 mm / min using a three-point bending test piece (6.8 × 13.6 × 83.0 mm) according to ASTEM E399. Was. The test piece was cut with a diamond cutter and dried in an oven at 60 ° C. for 3 hours. Next, the teeth of a cutter having a thickness of 0.25 mm were applied to the bottoms of the cutouts, and were hit several times with a mallet to crack.

(3) Glass transition temperature Using DSC41M manufactured by Shimadzu Corporation at a heating rate of 10
It was determined by differential scanning calorimetry at C / min.

[0040]

Example 2 An epoxy resin composition (2) of the present invention was obtained by repeating the same operation as in Example 1 except that the composition was changed as shown in Table 1. This epoxy resin composition (2)
The evaluation was carried out in the same manner as in Example 1 by using, and the results are shown in Table 1.

[0041]

Comparative Example 1 The same operation as in Example 1 was carried out except that 9.3 g of the copolymer (2) obtained in Reference Example 2 was used instead of the copolymer (1) used in Example 1. Repeat, comparative resin composition
(1) was obtained. Example 1 using this comparative resin composition (1)
The evaluation was performed in the same manner as described above, and the results are shown in Table 1.

[0042]

Comparative Example 2 A comparative resin composition (2) was obtained by repeating the same operation as in Example 1 except that the copolymer (1) in Example 1 was not added. Using this comparative resin composition (2), evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

[0043]

[Table 1]

[0044]

The epoxy resin composition of the present invention provides a cured resin having both high heat resistance and extremely high toughness which has never been obtained before, and is therefore of high industrial value for use in laminates and molding materials.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08L 35/00-35/06

Claims (3)

(57) [Claims] An epoxy resin (A) and 10 to 90 mol% of a structural unit (a) represented by the chemical formula 1 and 10 to 90 mol% of a structural unit (b) represented by the chemical formula (2) (provided that the structural unit ( a) and (b) wherein the total is 100 mol%). Embedded image (Wherein, R ₁ is water Motoma other is a methyl group, R ₂ is water
A hydrogen atom, an aliphatic saturated or unsaturated hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an acetyl group, a carboxylate group, an amide group, an alkoxy group or a cyano group. ) (Wherein, R ₃ and R ₄ are each independently hydrogen, halogen or a methyl group, R ₅ is hydrogen, halogen, alkyl, Ru Oh <br/> cycloalkyl group or an aryl group.) 2. The copolymer (B) comprises a structural unit derived from an aromatic vinyl compound as a structural unit (a) constituting the copolymer (B) and has a molecular weight in the range of 10,000 to 1,000,000. The epoxy resin composition according to claim 1, which has an average molecular weight of: 3. The epoxy resin (A) and the copolymer (B) in a ratio of 70 to 99% by weight of the epoxy resin (A) and 1 to 30% by weight of the copolymer (B). Item 7. The epoxy resin composition according to Item 1.