JPS62153317A - Epoxy resin cured product - Google Patents

Abstract

PURPOSE:To obtain the title cured product excellent in strength and modulus without sacrificing elongation, by mixing a specified additive for epoxy resin with an epoxy resin and a curing agent (cure accelerator), curing the obtained mixture and slowly cooling the cured product from its glass transition temperature to room temperature. CONSTITUTION:A low-molecular epoxy compound of formula I [wherein R3-4 are ach H or a 1-17 C (un)saturated aliphatic, aromatic or heterocyclic group which may be substituted with a halogen, nitro, alkoxy, allyloxy or acetyl] is reacted with at least one compound selected from those of formulas II-IV (wherein R1-2, R5-6, R9-10 and R13 are each R3 or R4 X is O, S, = N-R4 and R14 is R3 or R4) at room temperature to 180 deg.C and an epoxy group to NH group ratio of 1-5/5-1 to obtain an additive (B) for epoxy resin, of formula V, VI or VII (wherein R7-8 and R11-12 are R3 or R4). 100 pts. wt. resin composi tion (A) comprising an epoxy resin and a curing agent (cure accelerator) is mixed with 2-150 pts. wt. component B, the mixture is cured and the cured product is slowly cooled from its glass transition temperature to room tempera ture at a rate of 2 deg.C/min or above.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cured epoxy resin, and more specifically,
The present invention relates to epoxy resin materials that have excellent mechanical and electrical properties and are widely used as matrix resins for composite materials, insulating materials, adhesives, etc.

[Summary of the invention]

The present invention achieves high strength without sacrificing elongation by subjecting a cured epoxy resin product obtained by curing an epoxy resin composition containing specific additives to a specific heat treatment. Moreover, it is possible to obtain a cured epoxy resin having a high elastic modulus.

[Conventional technology]

Conventionally, epoxy resins have mechanical properties in their cured products,
In particular, it is widely used in adhesives and structural materials because of its excellent strength, elongation, and heat resistance, and in insulating materials because of its excellent electrical properties. However, the demands on the performance of these epoxy resins are also becoming higher. For example, when using epoxy resins as matrix resins for composite materials, resins with high rigidity are required.
When trying to improve rigidity by reinforcing the crosslinked structure, heat resistance increases too much, which deteriorates formability and significantly reduces elongation, leading to a lower strength development rate of reinforcing materials such as carbon fiber in composite materials. was there. For this reason, the emergence of an epoxy resin with a well-balanced stiffness and elongation in its cured product has been awaited.

[Problem that the invention seeks to solve]

As a result of intensive studies in view of the problems described above, the present inventors have found that by applying a specific heating and cooling treatment to a cured epoxy resin material that has been cured by adding specific additives, it has been found that it has significantly increased elasticity without sacrificing elongation. The present invention was completed based on the discovery that a cured resin product with a high yield can be obtained.

[Means for solving problems]

The gist of the present invention is the general formula (1) to R3CCH
2N Rz −−−−・−−1−−・−・−(L
)0HR.

s RIz R13R11CC
H2N CN R+o"-" (3) 1[11 0HR,X (R1 to R11 may be the same or different, hydrogen,
It is a saturated or unsaturated aliphatic group, aromatic group or heterocyclic group having 1 to 17 carbon atoms, and these groups may be substituted with halogen, nitro group, alkoxy group, allyloxy group or acetyl group.

X is oxygen, sulfur or =N-R,, group (R84 is hydrogen,
It is an aliphatic group, aromatic group or heterocyclic group having 1 to 17 carbon atoms, and these groups may be substituted with halogen, nitro group, alkoxy group, allyloxy group or acetyl group). ] and a curing agent, or a resin composition in which a curing accelerator is blended with this resin composition, is cured, and then the cured product is gradually cooled from its glass transition temperature to a temperature around room temperature. The object of the present invention is to provide a cured epoxy resin having a high elastic modulus, high strength, and high elongation.

The additives represented by the general formulas (1) to (3) are, for example, R, 0-N-C-N H-. and R13 have the same meanings as above), and specific examples include isocyanurates such as tris(2-hydroxyethyl)isocyanurate, ethanolamine, ethanolaniline, N.

N-dimethylethanolamine, N,N-diethylethanolamine, aminoethylethanolamine, N-methyl-N,N-jetanolamine, N,N-diisopropylethanolamine, N.

Amine compounds such as N-dipylethanolamine and N-methylmethanolamine, formic acid, acetic acid, propionic acid,
Examples include organic carboxylic acids such as benzoic acid, amide compounds of their thio and dithiocarboxylic acids, and urea and thiourea.

Examples of the compound represented by the general formula (4) include epichlorohydrin, phenylglycidyl ether, cyclohexene oxide, ethylene oxide, propylene oxide, butadiene oxide, dimethyl penkune dioxide, diglycidyl ether, butanediol diglycidyl ether, and ethylene glycol diglycidyl ether. , vinylcyclohexene dioxide, limonel dioxide, bis(2,3-epoxycyclopentyl) ether, divinylbenzene dioxide, diglycidyl ether of resorcinol, 2-glycidylphenylglycidyl ether, 3
．． 4-Epoxy-6-methylcyclohexylmethylcyclohexanecarboxylate, butyl glycidyl ether, styrene oxide, p-butylphenol glycidyl ether, glycidyl methacrylate, allyl glycidyl ether, cyclohexene vinyl monoxide, dipentene monoxide, α-pinene oxide, 3-( Examples include low molecular weight epoxy compounds such as pentadecyl phenyl glycidyl ether.

-i The amines, amides, and ureas represented by formulas (5) to (7) include methylamine, ethylamine, n-propylamine, n-butylamine, isopropylamine, 2-
Ethylhexyloxypropylamine, 3-ethoxypropylamine, di-2-ethylhexylamine, dibutylaminopropylamine diisobutylamine, 3-methoxypropylamine, allylamine, 5ec-butylamine, isopropanolamine, 2-ethylhexylamine, ethylenediamine, Aliphatic amines such as hexamethylene diamine, cyclohexylamine, dicyclohexylamine, aniline, p-aminobenzoic acid, 3,4
-Aromatic amines such as xylidine, m-xylene diamine, diaminodiphenyl, dibenzylamine, benzylamine, acetaldehyde ammonia, 4-aminopyridine, N-aminopropylmorpholine, bisaminopropyl biverizine, piperazine, 2- pipeyuline, piperidine, 5-fluorouracil, N-methylpiperazine, β-alanine, glycylglycine, glutamic acid, γ
-Amino acids such as aminobutyric acid, T-aminocaproic acid, and glycine, as well as these amines, aliphatic acids such as formic acid, acetic acid, and propionic acid, aromatic acids such as benzoic acid, and their monothio and dithiocarboxylic acids. Amide,
or single or mixed asymmetric ureas or thioureas, as well as acetoguanamine, 3-amino-1,2
, 4-) lyazole, isocyanuric acid, 2,4-diamino-6-(2'-methylimidazoyl-(1')-)ethyl-s-triazine, 2,4-diamino-6-(2'
-undecylimidacillin-(1')-)ethyl-8-
triazine, 2,4-diamino-6-(2'-ethyl-
4'-Methylimidacyline-(1'))-ethyl-8-
Imidazoles such as triazine, 2-methylimidazole isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 5,5'-dimethylhydantoin, benzoguanamine 1-methylol-5,5-dimethylhydantoin, melamine, 1. 3-diphenylguanidine, di-0-triguanidine, 1-0-tribiguanide, N,N'-diphenylthiourea, 2-mercapto-2-imidacillin, N.

Examples include N'-diethylthiourea, N,N'-dipylthiourea, N,N'-dilaurylthiourea and the like.

Compounds represented by general formula (4) and general formulas (5) to (7)
The reaction with the compound shown is carried out without a solvent or with an organic solvent,
For example, in an aromatic solvent such as benzene or toluene, an aliphatic solvent such as hexane or ligroin, a halogen solvent such as carbon tetrachloride, chloroform, or an ether solvent such as dioxane or tetrahydrofuran, under stirring at a temperature from room temperature to 180°C. All you have to do is react. The ratio of epoxy groups to NH groups at this time is preferably in the range of 115 to 5/1, more preferably in the range of 1/1.5 to 1.5/1.

In addition, the method of reaction of both the compounds is not particularly limited, but
It is desirable to proceed with the reaction while adding the epoxy compound represented by the general formula (4) to the amine, amide or urea represented by the general formulas (5) to (7). The composition after the reaction may be determined by determining the amount of epoxy groups if there is an excess of amine groups, or by determining the amount of NH groups if there is an excess of epoxy groups, but it is not necessary that all the compounds react.

The additives represented by the general formulas (1) to (3) can be used in a resin composition consisting of an ordinary epoxy resin and a curing agent, or in a resin composition 100 in which a curing accelerator is blended with this resin composition.
It is preferable to add 2 to 150 parts by weight based on the weight part. Here, if it is less than 2 parts by weight, no substantial effect will be obtained, and if it exceeds 150 parts by weight, the heat resistance will be significantly lowered, which is not preferable. Also, the general formulas (1) to (3)
) It is preferable that the molecular weight of the additive is 5,000 or less; if it exceeds this value, it becomes a solid, which is disadvantageous in terms of handling or mixing and stirring, and tends to reduce its contribution to improving the rigidity of the resin. .

The epoxy resin used in the present invention may be any commonly used epoxy resin, including polyglycidyl ethers of diphenylolalkanes such as diphenylolpropane, diphenylolethane, and diphenylolmethane, novolac, and Epoxy resins produced by epoxidation of polyglycidyl ethers of polyhydric phenols such as resols, alicyclic compounds such as cyclohexane, cyclopentadiene, and dicyclopentadiene, such as (3,4-epoxy-6-methyl -cyclohexane)-methyl ester, poly(epoxyalkyl)ethers of aliphatic polyoxy compounds such as ethylene glycol and glycerin, and epoxyalkyl esters of carboxylic acids such as glycidyl ethers of aromatic and aliphatic carboxylic acids. It will be done. Also, epoxy resins are disclosed in U.S. Patent Nos. 3,390,037 and 297,098
It may be a precondensate of an epoxy resin and a curing agent as described in Nos. 3 and 3,067,170;
It may be a simple mixture. These may be used alone or in combination of two or more.

Examples of the curing agent used in the present invention include O-phenylenediamine, m-phenylenediamine, 4,4'-methylenedianiline, 4,4'-diaminodiphenylsulfone, 3.
Aromatic polyamines such as 3'-diaminodiphenylsulfone, m-xylene diamine, triethylenetetramine,
Diethylene, triamine, 1,3-diaminocyclohexane, menthanediamine, cyanoethylated diethylenetriamine, N-aminoethylpiperazine, methyliminobispropylamine, aminoethylethanolamine,
Aliphatic polyamines such as polyether diamine and polymethylene diamine, phthalic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, trimellitic anhydride, itacone anhydride acids, citraconic anhydride, dodecenylsuccinic anhydride, fluorene disocnic anhydride, maleic anhydride adduct of methylcyclopentadiene, methyltetrahydrophthalic anhydride, lyluyl acid adduct of maleic anhydride, cyclobencunetetracarboxylic anhydride, Acidic substances having polycarboxylic acid groups, polycarboxylic acid anhydride groups, or mixed groups thereof such as alkylated endoalkylene tetrahydrophthalic acid anhydride, ethylene glycol bis trimellitite, glycerin tristrimetite, isophthalic acid dihydrazide, adipic acid Examples include dihydrazide, sebacic acid dihydrazide, α-hydrazides, polyamide amines, dicyandiamide, ketimine, and the like.

Examples of the curing accelerator include boron trifluoride complexes such as boron trifluoride monoengineered tylamine complex compounds and boron trifluoride piperidine complex compounds, 2-methylimidazole, and 2-methylimidazole.
Imidazole compounds such as ethyl-4-methylimidazole, triphenylphosphite, butanetetracarboxylic acid, 1,8-diaza-bicyclo-<5.4.0 )-undecene 7, N-(3-chloro-4-methoxy phenyl)-N'.

N'-dimethylurea, N-(4-chlorophenyl')
-N', N'-dimethylurea, N-(3-chloro-4
-ethylphenyl)-N', N'-dimethylurea, N
-(3-chloro-4-methylphenyl)-N', N'-
Dimethylurea, N-(3,4-dichlorophenyl)-
N', N'-dimethylurea, N-(4-ethoxyphenyl)-N'.

Examples include urea compounds such as N'-dimethylurea, N-(4-methyl-3-nitrophenyl)-N', and N'-dimethylurea.

The above-mentioned combination and quantitative ratio of the epoxy resin and curing agent may be carried out in the generally stoichiometric range, and when a curing accelerator is used, it is preferable to use the curing agent slightly below the stoichiometric ratio. In addition, if the additives shown in the general formulas (1) to (3) above contain a functional group that can contribute to curing, the amount of curing agent used should be adjusted depending on the functional group in the additive. It is preferable to reduce it.

As described above, the first element of the present invention is to add additives represented by the general formulas (1) to (3) to an epoxy resin, and cure the resin at room temperature or by heating depending on the composition. The second factor is to further improve the rigidity by subjecting the thus obtained cured epoxy resin to the heating and cooling treatment described below. In other words, if the resulting resin is cured at a temperature higher than the expected glass transition temperature, it may be used immediately after curing, but in general, the cured resin is cooled to room temperature after curing and then heated to at least the glass transition temperature of the cured resin. It is a process of reheating and gradually cooling from this glass transition temperature to room temperature. Here, it is sufficient to carry out the heating for several minutes until the polymer chains are in a state where they can move sufficiently. In addition, cooling after heating is preferably as fast as possible from the viewpoint of productivity and economy, but cooling from the glass transition temperature to room temperature is preferably performed at a rate of 2°C/min or less, more preferably at I'C/min.
Done at a speed of less than a minute. If cooling, that is, rapid cooling, is performed at a rate higher than this, there is a tendency that no improvement in rigidity can be expected.

In addition, in the present invention, when the resin cured product is at a temperature higher than the glass transition temperature, the cooling rate from the higher temperature to the glass transition temperature is not particularly limited.

Although it is not clear why the rigidity of a resin cured by adding the additives of the present invention is improved by heating and slowly cooling it,
It is thought that the hole-filling effect of the additive and the hydroxyl group generated due to the ring opening of the epoxy group form relatively strong hydrogen bonds, and that the heating and slow cooling facilitates the formation of hydrogen bonds.

〔Example〕 The present invention will be explained below with reference to Examples.

1-15 and " 11-12 The compound of general formula (4) shown in Table 1 and the compounds of general formulas (5) to (7) also shown in Table 1 are combined into (4)/
(5) to (7)-〇 were mixed and reacted at 150°C for 3 hours with stirring to obtain the desired synthetic additive. The target compound was identified using proton NMR by confirming that the peak due to the hydrogen atom attached to the nitrogen atom had disappeared. Next, Epicoat 82B as an epoxy resin
(Shell Chemical Co., Ltd.) 100 parts by weight of synthetic additives were mixed with 30 parts by weight of the synthetic additive, and stirred at 60°C for 10 minutes to mix uniformly.Furthermore, 30 parts by weight of diaminodiphenylmethane was added as a curing agent to this system. , and mixed uniformly for 10 minutes at 60°C to obtain a resin composition (A).Resin composition (A)
) at 90°C x 1 hour + 130° by cell casting method.
It was molded into a resin plate under cx1 hour curing conditions (Tg=10
0-110°C). After cooling this resin plate, it was heated at 180"C for 20 minutes, and then left in a furnace overnight for slow cooling to obtain a cured epoxy resin. The cooling rate at this time was 0.3°C. /min.The bending strength and bending elastic modulus of the resin plate thus obtained were measured.The results are shown in Table 1.

In addition, in comparative examples, the compounds represented by the general formula (4) and the compounds represented by the general formulas (5) to (7) were added to Epicote 828, and the compounds represented by the general formulas (5) to (7) were not added at all. When heating and cooling the epoxy resin cured product obtained by cooling in the same manner as in the example and the same resin plate as in the example, instead of slowly cooling it in a furnace, after heating, it was poured into water and quenched (at this time). Cooling rate is 20'C
/minute. ) I did four different things. The results are also shown in Table 1.

Example 16 MY-720 (tetrafunctional epoxy resin, manufactured by Ciba Geigy) was used as the epoxy resin, and the slow cooling rate after curing was set at 0.
A resin plate was obtained in the same manner as in Example 1 except that the heating rate was 5°C/min (Tg=179°C). The physical properties of this resin plate were as follows.

Bending strength 25.6 (kg/12) Bending modulus 538 Ckg/u+”) Bending elongation
6.8 [%] (The following is a margin, continued on the next page.) [Effects of the invention] As seen in Table 1, the cured epoxy resin of the present invention has the same properties as conventional epoxy resin without significantly sacrificing elongation. It has significantly higher strength and elastic modulus than resins, and therefore can be widely used in adhesives, cast products, molding materials, paints, etc. In addition, this epoxy resin cured product may be made of thermosetting resins other than epoxy resins, thermoplastic resins,
Furthermore, it can contain reinforcing materials such as glass fibers and carbon fibers, and is highly expected to be applied not only to general purposes but also to the fields of aviation and space.

Claims (1)

[Claims] 1. General formulas (1) to (3) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(2) ▲ There are mathematical formulas, chemical formulas, tables, etc.▼...(3) [R_1 to R_1_3 may be the same or different,
hydrogen, a saturated or unsaturated aliphatic group having 1 to 17 carbon atoms,
It is an aromatic group or a heterocyclic group, and these groups may be substituted with halogen, nitro group, alkoxy group, allyloxy group or acetyl group. X is oxygen, sulfur or =N-R_1_4 group (R_1_4
is hydrogen, an aliphatic group, an aromatic group, or a heterocyclic group having 1 to 17 carbon atoms, and these groups may be substituted with a halogen, a nitro group, an alkoxy group, an allyloxy group, or an acetyl group). . ] After curing a resin composition consisting of at least one of the additives for epoxy resins shown in the following, an epoxy resin and a curing agent, or a resin composition in which a curing accelerator is blended with this resin composition, this cured product is cured. A cured epoxy resin product obtained by gradually cooling the glass transition temperature from its glass transition temperature to around room temperature. 2. The additives shown by general formulas (1) to (3) each have ▲ mathematical formulas, chemical formulas, tables, etc. ▼... (4) and ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼... (5), ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (6) and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (7) [ R_1 to R_6, R_9, R_1_0 and R_1_3
may be the same or different, hydrogen, carbon number 1-17
is a saturated or unsaturated aliphatic group, aromatic group or heterocyclic group, which may be substituted with halogen, nitro group, alkoxy group, allyloxy group or acetyl group. X is oxygen, sulfur or =N-R_1_4 group (R_1_4
is hydrogen, an aliphatic group having 1 to 17 carbon atoms, an aromatic group, or a heterocyclic group, and these groups may be substituted with a halogen, a nitro group, an alkoxy group, an allyloxy group, or an acetyl group) It is. ] The cured epoxy resin product according to claim 1, which is obtained by reacting with any one of the following.