JPH0241313A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing a specific bisphenol A-based epoxy resin and epoxy resin curing agent, excellent in heat resistance, elastic modulus, hardness, toughness, flexibility, etc., and useful as civil engineering and building materials, coatings lining materials, adhesives, etc. CONSTITUTION:The objective composition containing (A) a bisphenol A-based epoxy resin, having 450-650 number-average molecular weight and 1.3-3.0 ratio of the number-average molecular weight to the weight-average molecular weight (weight-average molecular weight/number-average molecular weight) and (B) an epoxy resin curing agent (e.g., diethylenetriamine).

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention generally relates to an epoxy resin composition, and more specifically, it has excellent elastic modulus, hardness, and heat resistance, and in particular, excellent toughness. Epoxy resin compositions such as civil engineering and construction materials, paints, lining materials, adhesives, electrical equipment molding materials, mechanical parts, jigs and tools, matrix resins for fiber reinforced composite materials (hereinafter abbreviated as FRP), etc. can be obtained. This invention relates to an excellent epoxy resin composition.

[Conventional technology]

Epoxy resins are excellent in heat resistance, elastic modulus, hardness, and chemical resistance, and are particularly widely used in composite materials made of reinforcing fibers such as aramid fibers, glass fibers, and carbon fibers and matrix resins. However, conventional epoxy resins have various problems depending on the purpose and method of use.

In particular, when used as a matrix resin for FRP, there is a problem with the mechanical strength of FRP, especially its toughness, which affects impact resistance, fatigue properties, etc. Therefore, when using an epoxy resin as a matrix resin, the matrix resin,
In other words, in order to impart flexibility to a cured epoxy resin product and provide a cured epoxy resin product with excellent mechanical strength, particularly toughness, various methods such as selecting a curing agent or adding a flexibility imparting agent, etc. methods are being considered.

With such conventional methods, the flexibility of the cured epoxy resin product can be improved to some extent, but the elastic modulus is an original feature of the cured epoxy resin product.

A significant decrease in physical properties such as hardness and heat resistance was observed, and FR
Not only is it impossible to achieve a significant improvement in the toughness of P.

A problem arises in that chemical resistance, weather resistance, water resistance, etc. are also reduced.

On the other hand, JP-A-62-127317 discloses an epoxy resin composition for prepregs comprising at least two polyepoxy compounds, a high molecular weight epoxy resin, dicyandiamide, and/or a curing accelerator in the molecule. There is.

[Problem to be solved by the invention]

However, when such epoxy resin compositions are used as prepreg epoxy resin compositions, there are problems with tackiness, drape properties, resin flow properties, workability, storage stability, etc., and improvements are desired. was.

In order to improve this point, the inventors of the present invention previously proposed that ``contains a bisphenol A-based epoxy resin and an epoxy resin curing agent, and the bisphenol A-based epoxy resin has an epoxy equivalent of 190 or less and 40 parts by weight or less. "an epoxy resin composition characterized by having a total number average molecular weight of 600 to 1300" (Japanese Patent Application No. 63-773)
No. 25).

This epoxy resin composition has excellent tackiness, drapeability, workability, and storage stability when used as a prepreg resin, but according to subsequent studies by the present inventors, this epoxy resin has Because it has a high number average molecular weight and high melt viscosity.

The tack and drape properties are not necessarily good at room temperature or lower temperatures, and furthermore, the tack and drape properties change depending on the environmental temperature, and the properties are not stable over a wide temperature range. There was found.

The present invention was made in view of the above circumstances, and its purpose is to exhibit excellent tack and drape properties not only at high temperatures but also at room temperature or lower temperatures, and which also exhibits excellent tack and drape properties over a wide temperature range. The object of the present invention is to provide an epoxy resin composition that remains stable over a long period of time and provides a molded article with excellent mechanical properties such as toughness and flexibility.

[Means to solve the problem]

According to studies by the present inventors, it has been found that the above object can be achieved by using an epoxy resin having a number average molecular weight within a specific range and a specific molecular weight distribution.

That is, the epoxy resin composition of the present invention contains a bisphenol A-based epoxy resin and an epoxy resin curing agent,
The bisphenol A-based epoxy resin has a number average molecular weight of 450-700, and a ratio of weight average molecular weight to number average molecular weight (weight average molecular weight/number average molecular weight) of 1.
It is characterized by being 3 to 3.0.

The first characteristic of the epoxy resin used in the present invention is that its number average molecular weight is in the range of 450 to 700, preferably 500 to 650. If the number average molecular weight is less than 450, there will be too many low molecular weight components, the resulting prepreg will have poor tack and drape properties, resin flow will increase during curing, and the physical properties of the cured product, especially toughness, will deteriorate. However, the intended purpose of the present invention cannot be achieved. In addition, when the number average molecular weight exceeds 700, good physical properties of the cured product including toughness can be obtained, but the tackiness and drape properties at room temperature decrease due to the lack of low molecular weight components, and at lower temperatures. The tag properties and drape properties are further deteriorated, and it becomes impossible to handle it as a prepreg.

The second characteristic of the epoxy resin used in the present invention is that the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight l number average molecular weight) is 1.3 to 3.0. Preferably it is in the range of 1.5 to 2.7.

Ratio of weight average molecular weight to number average molecular weight (weight average molecular weight/
When the number average molecular weight is less than 1.3, the amount of low molecular weight components becomes too large, resulting in the same drawbacks as when the number average molecular weight is less than 450. Moreover, when the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight/number average molecular weight) exceeds 3.0, the high molecular weight component becomes too large.

If the number average molecular weight exceeds 700, the same results will occur, which is not preferable.

The bisphenol A-based epoxy resin used in the present invention is, for example, Epicoat 1001°1004 manufactured by Yuka Shell ■,
It can be prepared by appropriately combining 1007.1009.1010 (trade name) and the like.

In the present invention, as the epoxy resin curing agent, one or more kinds of arbitrary commercially available epoxy resin curing agents can be selected and used. As such a hardening agent, 1
For example, amines: aliphatic primary amines [polyamines (diethylenetriamine (DETA), triethylenetetramine (TTA), tetraethylenepentamine (TEPA)
), dipropylene triamine (DPTA), polymethylene diamine (trimethylhexamethylene diamine (TM)
D), polyether diamine, diethylaminopropylamine (DEAPA)), alicyclic polyamine (mencendiamine (MDA)), aliphatic amine containing an aromatic ring (meta-xylene diamine (MXDA)), aromatic primary amine [ metaphenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), aromatic diamine eutectic mixture], 3,9-
Bis(3-aminopropyl)-2,4,8,10-tetraspiro(5,5)undecane (ATU), modified amines (amine adducts, cyanoethylated polyamines), secondary and tertiary amines [linear diamines, linear tertiary amine,
Tetramethylguanidine, piperidine.

Pyridine, picoline, benzyldimethylamine, 2-(
dimethylaminomethyl)phenol (DMP-10))
, polyamide resin (condensate of dimer acid and polyamine)
; Acid anhydrides: aromatic acid anhydrides [(phthalic anhydride (PA)
), trimellitic anhydride (TMA), ethylene glycol bis(anhydrotrimellitate) (TME)
.

Glycerol tris (anhydrotrimellitate) (T
MG), pyromellitic anhydride (PMOA), 3,3'
, 4,4'-benzophenonetetracarboxylic anhydride (
BTDA)), cyclic aliphatic acid anhydrides [(maleic anhydride (MA), succinic anhydride (SA), tetrahydrophthalic anhydride (THPA).

Methyltetrahydrophthalic anhydride (Me-THPA),
Methylnadic anhydride (NMA), alkenylsuccinic anhydride, hexahydrophthalic anhydride (HHPA), methylhexahydrophthalic anhydride (Me-HHPA), methylcyclohexenetetracarboxylic anhydride (MCTC)
), aliphatic acid anhydride, polycarboxylic anhydride, halogenated acid anhydride, clodic anhydride (CA); polyamide resin (N,N'-bis(6-aminohexyl)adipamide), imidazoles [2 -Methylimidazole (2M
Z), 2-ethyl-4methylimidazo-# (2E4MZ
), 2-undecylimidazole (CIIZ), 2-heptadecyl imidazole (C17Z), 2-phenylimidazole (2PZ), 1-benzyl-2-methylimidazole (IB2MZ), ■-cyanoethyl-2-methylimidazole (2MZCM).

1-cyanoethyl-2-undecylimidazolium trimellitate (cuzcNs), 2,4-diamino-6
-[2-methylimidazolyl-(1)]-]ethyl-s
-triazine 2MZAZAZINE), quaternary salt (1-dodecyl-2-methyl-3-benzylimidazolium chloride), incyanurate (2-phenylimidazolium isocyanurate (2PZ-OK)), hydroxymethyl form (2-phenyl -4-Methyl-5-hydroxymethylimidazole (2P4M)lZ)), boron trifluoride-amine complex.

Dicyandiamide (DICY) and its derivatives, (0-
tolylbiguanide, α-2,5-dimethylbiguanide)
, organic acid hydrazide [succinic acid hydrazide (SaAD
ll).

Adipic acid hydrazide (AADH)), diaminomaleonite IJ/L/ (DAMN) derivative (DAMN)
BZ), melamine and its derivatives (diallylmelamine)
, amine imide (AI), polyamine salts, oligomers: synthetic resin initial charge (novolak phenol resin,
novolak cresol resin), polyvinylphenol (
(poly P-vinylphenol).

Such a curing agent is added in a stoichiometric amount to the bisphenol A-based epoxy resin.

In particular, when preparing an epoxy resin composition for carbon fiber reinforced prepreg, it is preferable to use dicyandiamide (DICY), diaminodiphenylmethane (DDM) and diaminodiphenylsulfone (DDS) as curing agents. As a result, an epoxy resin composition for prepregs having excellent tackiness, drapeability, resin flow, workability, and storage stability can be obtained.

Furthermore, when preparing an epoxy resin composition for use in mechanical parts, etc., acid anhydrides, diaminodiphenylmethane (DON), diaminodiphenylsulfone (DDS), and dicyandiamide (DICY) should be used in stoichiometric amounts as curing agents. is preferable, and can improve toughness, heat resistance, and machinability.

Furthermore, additives such as fillers and diluents can be used within the range that does not impair the properties described above.

According to another aspect of the present invention, when it is desired to improve heat resistance etc. even at the expense of some toughness, another epoxy resin different from the bisphenol A-based epoxy resin may be used as the epoxy resin component. It can be contained in an amount of 50 parts by weight or less per 100 parts by weight of the epoxy resin. In this case, if the content of other epoxy resins exceeds 50 parts by weight, the toughness will be significantly reduced, which is not preferable.

As the other epoxy resin, one or more kinds of epoxy resins that are usually reprinted can be selected and used,
For example, glycidyl ether-based epoxy resins (bisphenol A, F, S-based epoxy resins, novolac-based epoxy resins, brominated bisphenol A-based epoxy resins), cycloaliphatic epoxy resins.

Examples include glycidyl ester epoxy resins, glycidyl amine epoxy resins, and heterocyclic epoxy resins. In this case, the various curing agents mentioned above can be used as the curing agent, and are added in stoichiometric amounts.

Of course, additives such as fillers and diluents can be used to the extent that desired properties are not lost.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 5 In this example, as bisphenol A-based epoxy resins, Epicote 828 (epoxy equivalent weight 184 to 194, number average molecular weight 380), 1001 (epoxy equivalent weight 450 to
500, number average molecular weight 900), 1004 (epoxy equivalent weight 875-975° number average molecular weight 1600), 100
7 (epoxy equivalent 1750-2200, number average molecular weight 2900), 1009 (epoxy equivalent 2400-33
00, number average molecular weight 3750) and 1010 (epoxy equivalent weight 3000-5000, number average molecular weight 5500) (
A matrix resin for a prepreg was prepared by preparing Yuka Shell (trade name) using dicyandiamide (DICY) as a curing agent in the proportions shown in Table 1-1.

In Example 5, Epikote 152 (epoxy equivalent: 172 to 179, average molecular weight: 37
0) (manufactured by Yuka Shell ■, trade name) was added in an amount of 20 parts by weight.

To explain further, in each Example, the epoxy resin components shown in Table 1 were mixed under heating at 150°C. This mixture was cooled to 80° C., and dicyandiamide (DICY) was added in a stoichiometric amount to prepare an epoxy resin composition exhibiting high toughness at room temperature.

This was poured into a mold consisting of two glass plates and a Teflon spacer, heated at 100°C for 2 hours, then further heated to 200°C.
It was heated in an oven for 2 hours to cure.

The epoxy resin cured product thus obtained was 30c+
*A test piece was cut out from a resin casting plate measuring 30 cm x 3 mm, and its impact strength (IZOD) was measured. The results are shown in Table-1. Moreover, this epoxy resin had tackiness, drapeability, resin flowability, handlingability, and storage stability suitable for use in prepregs, and was particularly excellent in toughness.

In addition, carbon fibers (strength 350 kg/+am", elastic modulus 3
2t/am") to obtain a prepreg. This prepreg has excellent tackiness, and the tackiness does not change even in the temperature range of 15 to 30°C, indicating that there is no temperature dependence of tackiness. It was.

Next, 12 layers of this prepreg were laminated and heated under the above-mentioned curing conditions to obtain a molded body. Table 1 shows the results of measuring the compressive strength after impact (CAI) of this molded body. Example 1
．． 2.3.4 and 5 compositions have good workability during production,
Moreover, the above-mentioned properties as a prepreg were also good.

Comparative Examples 1-5 Epoxy resin compositions, prepregs, etc. were prepared and tested in the same manner as described in Example 1-5 above using the composition ratios shown in Table-1.8 The results are shown in Table-1. show.

When compared to the present invention, it can be seen that tackiness, tack stability (temperature dependence of tackiness), storage stability, toughness, etc. are poor.

The drawings show data on the temperature dependence of the tackiness of prepregs using the epoxy resin composition of Example 3, the epoxy resin composition of Comparative Example 2, and the epoxy resin composition of Comparative Example 5 as matrix resins.

From the drawings, even if the number average molecular weight of the epoxy resin is 534 as in Comparative Example 2, the tack value decreases as the temperature rises when the ratio of the weight average molecular weight to the number average molecular weight is less than 1.3. It can be seen that the operability is poor because the tackiness changes drastically. In addition, when the number average molecular weight of the epoxy resin exceeds 700 as in Comparative Example 5, even if the weight average molecular weight and number average molecular weight are within the range of 1.3 to 3.0, the prepreg deteriorates as the temperature rises. It is understood that handling of the prepreg becomes difficult if it becomes too hard.

In contrast, the tack value of the prepreg using the epoxy resin matrix of the present invention (Example 2) remains within the appropriate level of 200 to 300 g even when the temperature changes, and its storage stability and workability are It can be seen that the results are good.

The tack value is 30. Cut the coated sample into a 1cI1 width strip,
This tack measuring device (Pikmatack manufactured by Toyo Seiki)
The sample was fixed to two sample holders, upper and lower, and after being pressed for a few seconds, it was peeled off at a constant speed (20 mm/min), and the stress at that time was taken as the tack value of the sample.

〔Effect of the invention〕

The epoxy resin composition according to the present invention configured as described above has a cured epoxy resin product obtained from the composition that has excellent heat resistance, elastic modulus, hardness, and chemical resistance, as well as toughness and flexibility. It has excellent flexibility and impact strength, as well as breaking strength, crack resistance against thermal shock, adhesion, and adhesion. Prepreg containing this material exhibits excellent tack and drape properties not only at high temperatures but also at room temperature or lower temperatures, and these properties remain stable over a wide temperature range, resulting in improved workability and Storage stability increases several times.

[Brief explanation of the drawing]

The drawing is a graph comparing the tack value and tack stability (temperature dependence of tack value) of prepregs using the epoxy resin composition according to the present invention and the epoxy resin composition according to a comparative example as matrix resins. Patent applicant Toa Fuel Industries Co., Ltd.

Claims (1)

[Claims] (1) Contains a bisphenol A-based epoxy resin and an epoxy resin curing agent, and the bisphenol A-based epoxy resin has a number average molecular weight of 450 to 700, and the ratio of the weight average molecular weight to the number average molecular weight (weight average Molecular weight/
An epoxy resin composition having a number average molecular weight of 1.3 to 3.0.