JPH01110526A - Epoxy resin composition for prepreg - Google Patents

Abstract

PURPOSE:To obtain the subject composition for prepreg, having long pot-life even at a high temperature and curable in a short time under heating, by compounding an epoxy resin with a specific one-pack type master batch hardener for epoxy resin at a specific ratio. CONSTITUTION:The objective composition is composed of (A) 100pts.wt. of an epoxy resin and (B) 2-60pts.wt. of a one-pack type master batch hardener composed of (i) a hardener consisting of a core composed of (a) 1-20pts.wt. of dicyandiamide and (b) a powdery amine compound containing at least one tert-amino group in one molecule, free from primary or secondary amino group, and having a bonded group absorbing infrared ray of 1,630-1,680cm<-1> wavenumber and a bonded group absorbing infrared ray of 1,680-1,725cm<-1> wavenumber at least on the surface and a shell composed of (c) a reaction product of the component (b) and an epoxy resin and (ii) 10-50,000pts.wt. (based on 100pts.wt. of the component i) of an epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an epoxy resin composition for prepreg. More specifically, the present invention relates to an epoxy resin composition for prepregs that has a relatively long pot life even at high temperatures, cures in a short time under heat curing conditions, and provides excellent heat resistance.

(Prior art and its problems) Epoxy resin has excellent properties such as mechanical properties, electrical properties, thermal properties, chemical resistance, and adhesive properties of its cured product, so it is used as an insulating material for electrical and electronic applications. Widely used in the fields of , adhesives and paints.

One typical example is a prepreg base material based on carbon fiber, glass fiber, etc. Conventionally, epoxy resin compositions for prepregs include (1), a suphenol type or novolac type epoxy resin, and a 2- 1 composition consisting of a lower alkyl group-substituted imidazole compound such as methylimidazole, (2) a bisphenol type or novolac type epoxy resin, dicyandiamide, and 2)
．． 4.6-) Compositions consisting of lis(dimethylamino)methylphenol, borosulfide trifluoride, or 3-(3,4-dichlorophenyl)-1,1-dimethylurea are known. .

However, the composition (1) described above has poor storage stability;
For example, when storing or transporting a prepreg made by impregnating glass cloth, carbon cloth, etc. with the composition at room temperature, it retains the same performance as immediately after preparation for a few days at most, and for longer than that. Over time, not only will its performance deteriorate significantly, but it may even become unusable. Therefore, during storage or transportation, it is necessary to use a cooling medium such as dry ice at a low temperature, resulting in poor workability and economic efficiency.

In addition, the composition of ratio (2) above has a slightly longer performance retention period (about a week) than the composition of ratio (1) above, but requires a high curing heating temperature of 130°C or higher during curing. Not only that, but also post-heating is required. Since such high-temperature curing is required, there is a disadvantage that the ABS resin molded product is deformed, for example, when an integrally molded product with an ABS resin molded product is obtained. For these reasons, when combining or integrating parts, it is necessary to create them separately and use adhesives to join them together, which results in poor workability.
In addition, thermal energy is required to raise the temperature, making it less economical.

On the other hand, as an epoxy resin composition with poor pot life, workability, chemical resistance, etc., for example, epoxy resin 45 to 87, which is composed of 60 to 95 parts by weight of solid epoxy resin and 40 to 5 parts by weight of liquid epoxy resin. parts by weight and 10. parts by weight of solvent. ~4
5 parts by weight, a riazine alkyl group of the general formula (wherein R1 is carbamoylalkyl, cyanoalkyl, carboxyalkyl, carbalkoxyaryl, or diamino-8-), R2 is an H atom, an alkyl or aryl group, and R3 is H an epoxy composition comprising 3 to 10 MM parts of a curing agent containing an imidazole derivative represented by an atom or an alkyl group (it is a H atom or an alkyl group) and dicyandiamide in a ratio of 9:1 to 1:9. things are being proposed. (Refer to Japanese Patent Publication No. 60-3113).

Further, in JP-A No. 62-100518, the curing agent system has the following structural formula % (where n is an integer of 10-20, R□, R21R
An epoxy resin for pregregs has been proposed, which is characterized by containing an imidazole derivative and dicyandiamide, in which s is the same or different and represents a hydrogen atom, a lower alkyl group, or an aryl group. Products also do not have sufficient storage stability at room temperature, and therefore must be used within a short time after preparation, and in order to be usable over a long period of time, they must be stored at low temperatures. Furthermore, since these compositions generally use solvents, there are major challenges in improving the working environment, solving pollution problems, and making them solvent-free for the purpose of saving resources.

(Problems to be Solved by the Invention) The present invention provides an epoxy resin composition that solves the above-mentioned problems and is particularly suitable for producing prepregs.

(Means for Solving the Problems) The present invention relates to an epoxy resin composition comprising an epoxy resin and a specific curing agent system. Specifically, the curing agent system is (1) dicyandiamide 5 with respect to 100 parts by weight of the epoxy resin. ~
25 parts by weight, and (II) at least 3 parts per molecule.
A bonding group (3) having a primary amino group but no primary or secondary amino group and absorbing infrared rays with a wave number of 1630 to 16803'' and a bonding group (3) that absorbs infrared rays with a wave number 1680 to 1725c!M-1. A curing agent (I) consisting of a powdery amine compound (4) having at least Y) on its surface as a core, and a reaction product of the amine compound and an epoxy resin as a shell, and the curing agent (I) An epoxy resin composition for prepregs comprising 2 to 60 parts by weight of a masterbatch type curing agent for liquid epoxy resins, consisting of lO to so, ooo parts by weight of epoxy resin CB per 100 parts by weight.・According to the epoxy resin composition for prepreg of the present invention, the following effects can be obtained.

(1) The resulting prepreg has no change in performance at room temperature and can be stored stably for a long period of time, so unlike conventional products, there is no need to use a cooling medium such as dry ice during storage or transportation. .

(2) Since the curing agent system is a combination of high temperature active dicyandiamide and a specific master patch type curing accelerator,
When impregnating with this composition, the viscosity can be lowered by heating without using a solvent, and since there is little change in the viscosity of the face, it is possible to manufacture prepreg under stable operating conditions, and the resulting product The quality is constant.

(3) Conventionally, this type of composition required heating temperatures of 130°C or higher during curing, and required post-heating, resulting in poor economic efficiency and workability, but the present invention The compositions can be cured at relatively low temperatures (100-110°C).

(4) The obtained cured product has good heat resistance.

The epoxy resin used in the present invention is not limited to the above, and may be any resin having an average of two or more epoxy groups per molecule. For example, bisphenol A
1. Polyglycidyl ether obtained by reacting epichlorohydrin with polyhydric phenols such as bisphenol F, cole, and resorcinol, or polyhydric alcohols such as glycerin and polyethylene glycol, or p-oxybenzoic acid and β-oxynaphthoic acid. Glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as hydroxycarboxylic acid with epichlorohydrin, or a polyglycidyl ester obtained by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin, or 4,4'-diaminodiphenylmethane. Yam
- Glycidylamine compounds obtained by reacting aminophenol etc. with epichlorohydrin, further K include epoxidized novolak resins, epoxidized cresol novolak resins, epoxidized polyolefins and other urethane-modified epoxy resins, but these are limited in scope. isn't it.

The dicyandiamide used in the present invention is preferably one having an average particle size of 50 μm or less, which can be obtained by finely pulverizing it with, for example, a "Zimat pulverizer" (manufactured by Nippon Pneumatic ■).

The particle size in the present invention refers to the Stokes diameter measured by the centrifugal sedimentation method or sedimentation method shown in Tables 4 and 4 of the Japan Powder Industry Technology Association Cotton "Agglutination Engineering" (published in 1981). It is something. Moreover, the average particle diameter refers to the mode diameter.

Below, the components that make up the one-component epoxy resin masterbatch curing agent used in the present invention will be explained in detail.

The master patch type curing agent used in the present invention is a mixture of curing agent (I) and epoxy resin at a fixed ratio. First, the curing agent (I) will be explained. The curing agent (I) is composed of a core made of a powdered amine compound (4) and a shell made of a reaction product of this amine compound (4) and the epoxy resin Q3).

The powdered amine compound (2) here is obtained by processing the powdered amine compound (a) having a tertiary amino group. Examples of the powdered amine compound (a) having a tertiary amino group include the following.

(1) A reaction product (a -X>: However, reaction products having an IC, a primary amino group, or a secondary amine group in the molecule are excluded.

(2) Imidazole compound (a-2) The raw materials for the reaction product (a-1) will be explained.

As the compound having one or more primary amine groups in one molecule, any of aliphatic primary amines, alicyclic primary amines, and aromatic primary amines may be used.

Examples of aliphatic primary amines include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine,
Examples include methanolamine, ethanolamine, propatoolamine, diethylaminoprobylamine, and the like.

Examples of the alicyclic primary amine include cyclohexylamine, isophoronediamine, and aminoethylhyherazine.

Aromatic primary amines include aniline, toluidine,
Examples include diaminodiphenylmethane and diaminodiphenyl sulfone.

As the compound having one or more secondary amino groups in one molecule, any of aliphatic secondary amines, alicyclic secondary amines, aromatic secondary amines, imidazole compounds, and imidacillin compounds may be used.

Examples of aliphatic secondary amines include dimethylagne,
diethylamine, dipropylamine, dibutylamine,
Examples include dipentylamine, diethylamine, dimethatolamine, jetanolamine, dibrobanolamine, and the like.

Examples of the alicyclic secondary amine include dicycloheyacylamine and N-methylpibe2zine.

Examples of the aromatic secondary amine include diphenylamine, phenylmethylamine, and phenylethylamine.

Imidazole compounds include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-dodecylimidazole, 2-
undecylimidazole, 2-phenylimidazole,
Mention may be made of 2-heptadecyl imidacillin, 2-ethyl-4-methylimidazole and the carboxylic acid salts of the imidazole compounds mentioned here.

Examples of the imidacilline compound include 2-methylimidacillin, 2-phenylimidacillin, 2-undecylimidacilline, 2-heptadecyl imidacilline, and the like.

Examples of other raw materials for the reaction product (a-1) will be described below.

Carboxylic acid compounds: for example, succinic acid, adipic acid, sepacic acid, phthalic acid, danomer acid, etc.

Sulfonic acid compounds: e.g. ethanesulfonic acid, P-)
Sodium luenesulfonate.

Incyanate compounds: for example, tolylene diincyanate), 4,4'-diphenylmethane diisocyanate,
such as hexamethylene diisocyanate.

Epoxy compound: Any one of a monoepoxy compound, a jepoxy compound, a polyepoxy compound, or a mixture thereof may be used.

Monoepoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, para-xyl glycidyl ether, glycidyl acetate, glycidyl butyrate,
Examples include glycidyl hexoate, glycidyl benzoate, and epoxy resin.

Examples of jepoxy compounds include bisphenol A1 bisphenol F1 catechol, divalent heptadol compounds such as resorcinato, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, 1.4-y'methaneol, and neopentyl glycol. diglycidyl compounds obtained by reacting dihydric alcohol compounds such as, hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid, dicarboxylic acids such as phthalic acid, terephthalic acid, and hexahydrophthalic acid with epichlorohydrin, 3 ,4-epoxy-6
-methylcyclohexylmethyl-3,4-epoxy-6
-Methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane)carboxylate, and other alicyclic epoxy compounds.

A preferred amine compound (a-1) is a reaction product of N-methylpiperazine or diethylaminepropylamine and an epoxy compound, and the amount of active hydrogen atoms in the secondary amine is equal to 1% mk of epoxy in the epoxy compound.
It is obtained by reaction.

The imidazole compound (a-2) includes 1-cyanoethyl-2-undecyl-imidazole-trimelitate, imidazolylsuccinic acid, 2-methylimidazolesuccinic acid, 2-ethylimidazole succinic acid, 1-cyanoethyl-2-methylimidazole, l-cyanoethyl-2
-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, and the like.

As a preferred amine compound (a), a primary or secondary amine and an epoxy-containing compound are reacted at a ratio of 0.8 to 1-2%i of the epoxy group of the epoxy compound to the active hydrogen atom 1'i+ff1- of the amine compound. Examples include products obtained by

Among these amine compounds (a), imidazole derivatives having one or more hydroxyl groups in one molecule are preferred in order to obtain those with particularly excellent curing ease and storage stability.

A more preferred amine compound to be used is a compound having at least two hydroxyl groups in the molecule, which is produced by the reaction of an imidazole compound with a compound having at least two epoxy groups in the molecule. Examples of such imidazole derivatives include addition compounds of imidazole compounds or carboxylates of imidazole compounds and compounds having one or more epoxy groups in one molecule. As the imidazole compound used,
Imidazole, 2-methylimidal, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-
Examples include isopropylimidazole, 2-undecylimidazole, 2-phenylimidazole, and their carboxylic acid salts. Examples of carboxylic acids include acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, and the like.

Compounds having one or more epoxy groups in one molecule include butyl glycidyl ether, hexyl glycidyl ether, p-xyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl Examples include monoepoxy compounds such as hexoate, glycidyl benzoate, allyl glycidyl ether, pt-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, and epoxy resins.

In order to obtain excellent curability and storage stability, 2-methylimidazole or 2-
Nine compounds selected from ethyl-4-methylimidazole or a mixture thereof are preferred, and as the epoxy compound, an epoxy resin obtained by reacting bisphenol A and epichlorohydrin is most preferred.

This adduct of imidazole compound and epoxy compound is
The reaction can be carried out by reacting 1 to 5 moles of imidazole with 1 to 5 moles of an epoxy compound by a conventionally known general method.

The average particle size of the powdered amine compound (4) having the 37th mino group is not particularly limited, but if the average particle size is too large, it may reduce the curability or deteriorate the mechanical properties of the cured product. It may cause damage. Preferably, the average particle size does not exceed 50A; if the average particle size becomes larger than this, chemical resistance and mechanical strength of the cured product will deteriorate. Optimally it should not exceed 10μ.

The compound used (in Shu, primary amino group or secondary
The purpose of excluding those having R-amino groups is to avoid the viscosity of the compounded product from becoming extremely high when compounding compounds having these groups with epoxy resins, especially liquid epoxy resins. 0 1630-1680 c in powdered amine compound (4)
The bonding groups absorbing infrared rays of 1680-1725a++-1 and 1680-1725a++-1 can be measured using an infrared spectrophotometer. It can be analyzed in detail.

Among the bonding groups having an absorption of 1630 to 1680 cm, a urea bond can be mentioned as a particularly useful one.

A bonding group (7
), which one is particularly useful? can be mentioned.

These urea bonds and billet bonds are produced by the reaction of an incyanate compound with water or an amine compound having one or more primary amino groups in one molecule.

Incyanate compounds that are used to form a urea bond, which is representative of the bonding group (3), and a billet bond, which is representative of (g), include compounds having one or more incyanate groups in one molecule. However, it is preferable to use a compound having two or more incyanate groups in one molecule. Typical incyanate compounds include aliphatic diisocyanates, cycloaliphatic diisocyanates, aromatic diisocyanates, and aliphatic triisocyanates.

Examples of aliphatic diisocyanates include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, and hexamethylene diisocyanate.

Examples of alicyclic diisocyanates include inhopone diisocyanate-F and 4aC-dicyclohexylmethane diisocyanate.

As examples of aromatic diisocyanates, mention may be made of tolylene diisocyanate, 4,4'-diphenylmethane diincyanate, xylylene diisocyanate and polymethylene polyphenyl polyisocyanate.

Examples of aliphatic triisocyanates include 1,3°6-
Mention may be made of triisocyanate methylhexane.

In addition, the above incyanate compound and 2 hydroxy acids in one molecule.
1! 7 ducts with compounds having i, for example reaction products of isocyanate compounds and α,ω-dihydroxyalkanes, reaction products of incyanate compounds and bisphenols, can also be used. Pre-reaction products of incyanate compounds and water can also be used.

One or more primary amines in one molecule to form a urea bond or biuret bond, which is representative of bonding groups (3) and (2) 2! As the amine compound having i:, aliphatic amines, alicyclic amines, and aromatic amines can be used.

Examples of aliphatic amines include alkylamines such as methylamine, ethylamine, propylamine, butylamine, alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine,
Polyalkylene polyamines such as sodium ethylene pentamine can be used.

Examples of alicyclic amines include cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, inphorondiamine, and the like.

Examples of aromatic amines include aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, diaminodiphenylsulfone, and the like.

In the powdered amine compound (4), the bonding group (1) and the bonding group (7) preferably have concentrations in the range of 1-1000 meqA and x, xooomeq/'Kg, respectively. The concentration of the bonding group (3) is 1 meq/Ky
If it is too low, the mechanical strength of compound (4) is not sufficient and the pot life of the blended product is short. Also, 1000m
When 6q,/ is higher than 9, curability deteriorates and high temperature curing is required, which is not practical. A more preferable concentration range of the bonding group (3) is 10 to a o o meq/X9
0 If the concentration of the bonding group (7) is lower than 1 meq/Ky, the mechanical strength of the compound (3) is insufficient and the pot life of the compounded product is short. Ma-1p, lo o o meq/
If the Kf is higher, the curing properties will be poor and high temperature curing will be required, making it impractical. A more preferable range of the bonding group (7) is 10 -200 meq/Kp.

In addition to the bonding group (3) and the bonding group (a), the powdery amine compound (4) is preferably one having a wave number of 1730 to 1.
755 cm-'' of a bonding group that absorbs infrared radiation.

This bonding group G! , ), particularly useful are carbonyl groups such as urethane bonds. This urethane bond is produced by a reaction between an isocyanate compound and a compound having one or more hydroxyl groups in one molecule.

Compounds having one or more hydroxyl groups in one molecule that are used to generate urethane bonds, which are a substitute for the bonding group (■), include l1fj aliphatic saturated alfur, aliphatic unsaturated alcohol, II! Alfur compounds such as heptocyclic acyclic alcohols, aromatic alcohols, and phenol compounds can be used.As the aliphatic alcohols, methyl alcohol, ethyl alcohol, propyl alcohol, methyl alcohol,
Monoalcohols such as amyl alcohol, hexyl alcohol, hexyl alcohol, octyl alcohol, nonyl alcohol, tepyl alcohol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, stearyl alcohol, eicosyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl Examples include ethylene glycol monoalkyl ethers such as ether, ethylene glycol monobutyl ether, and ethylene glycol monohexyl ether. Other dihydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene gelylcol, l,3-butanediol, neopentyl glycol, trihydric alcohols such as glycerin, trimethylolpropane, and tetrahydric alcohols such as pentaerythritol. Mention may be made of alcohols.

Aliphatic unsaturated alcohols include allyl alcohol,
Examples include crotyl alcohol and crotyl alcohol.

Examples of alicyclic alcohols include cyclopentanol and cyclohexanol.

Aromatic fulcor,! : L-'01, hensyl alcohol, cinnamyl alcohol, and other monoalcohols can be mentioned.

In these alcohols, either the primary alcohol or the secondary alcohol may be a tertiary alcohol. In addition, compounds that have one or more epoxy groups in one molecule, and compounds that have one or more epoxy groups in one molecule,
Compounds having one or more secondary hydroxyl groups in one molecule obtained by reaction with a compound having one or more hydroxyl groups, carboxyl groups, primary or secondary amino groups, or mercapto groups can also be used as alcohol compounds.

Examples of phenolic compounds include monohydric phenols such as carbolic acid, cresol, xylenol, carvacrol, thymol, and naphthol, dihydric phenols such as catechol, resorcinol, hydroquinone, bisphenol A1 and bisphenol F, and trivalent phenols such as pyrogallol and phloroglucinato. ! /-Af can be mentioned.

Preferred compounds having -co or more hydroxyl groups in the molecule are alcohol compounds or phenol compounds having divalent or more hydroxyl groups.

The preferred concentration range of the binding group (Z) in the powdered amine compound (4) is 1-200 meq/Kr. When the concentration of the bonding group (Z) is lower than 1 meq/Kf, the pot life of the compounded product is short. Moreover, if it is higher than 200 meq/Kf, the curability is poor and high temperature curing conditions are required, which is not practical. A more preferable concentration range of the bonding group (Z) is 5 to 10 meq/Kg.

Further, the concentration ratio of the bonding group (7) to the total concentration of the bonding group (3) and the bonding group (7) is preferably in the range of 0.05 to 1.0. Concentration ratio is 0.0
If it is smaller than 5, the cohesive force of compound (B) becomes strong, and the curing temperature needs to be set higher than the practical range; On the other hand, when it is larger than O, the cohesive force of compound (B) is weak, the storage stability of the compounded product is poor, and the resistance to mechanical shearing force is also reduced.

Quantification of the concentration of the bonding group and the bonding group (T) was carried out using model compounds shown in formulas (1) and (2) having the respective bonding groups, and model compounds having no bonding group and the bonding group (T), and After creating a calibration curve using a quasi-substance that has a functional group that absorbs infrared rays of a specific wavelength, the quasi-substance 8 and powdered amine compound (4) are mixed at a certain ratio, and the infrared rays of the mixture are absorption intensity, i.e. 1630-1680 c
m-" and 1680 #1725c1!1-", and the recognition can be calculated from the detected Bk line.

Examples of standard substances include 2,3-dimethyl and 2,3-dicyanobutane;
The absorption intensity based on the cyano group present at 2250 cm-'' can be utilized.

In addition, the quantification of the bond ti■) is carried out using the model compound shown in formula (3) and 2, as well as the bonding group (3) and the bonding group (7).
It can be carried out using 3-dimethyl and 2,3-dicyanobutane.

As a method for producing the masterbatch type curing agent used in the present invention, for example, a powdered compound (a) having a flc3 amino group is dispersed in an epoxy resin (B) in advance, and an incyanate compound is added thereto. , a method in which the reaction is carried out in the presence of water. This reaction allows a shell to be formed on the surface of the core. The n-degree adjustment of the bonding groups ①, (a), and (Z) in the powdered amine compound (4) that is the core is ① the amount relative to the compound (a) having the 37th mino group, ② the 37th mino group? This can be carried out by changing the amount of the incyanate compound and the type of incyanate relative to the compound (a).

In order to pre-disperse the powdered compound (a) having the 37th ζ group in the epoxy resin (1), it is preferable to mix it while applying mechanical shearing force, such as with a triple roll.

The epoxy resin (B) is selected from the epoxy resins (B) described above.

The average thickness of the shell covering the surface of the core made of the powdered amine compound (4) is preferably 50 to 100 OOA. Below 50A, the pot life is insufficient (,100A
If it exceeds OOA, the curing temperature will become too high, making it impractical. The layer thickness here is observed using a transmission electron microscope. A particularly preferable shell thickness is the average layer J
1 is lOO~100OA.

The epoxy resin (B), which is an essential component of the masterbatch type curing agent used in the present invention, is a medium for reacting a compound (a) 'x having a 37th amino group with an incyanate compound in the presence of water. Although it has a role as
Furthermore, a part of the epoxy resin (B) reacts with the powdered amine compound (4) to form a shell, thereby playing an active role in improving storage stability as a curing agent.

The weight ratio of the powdered aquine compound to the epoxy resin (B) is 110, in the range of 1 to 11,500. 110.1
If the size is too large, the powdered amine compound (4) cannot be dispersed in the epoxy resin (B).

If it is smaller than 11,500, it will not exhibit its performance as a curing agent. Preferably it is 1/1 to 115.

The masterbatch type curing agent used in the present invention is liquid or pasty at room temperature.

The epoxy resin composition of the present invention is obtained by uniformly mixing an epoxy resin, dicyandiamide, and a masterbatch type curing agent.

The mixing amount is determined from the viewpoint of curability and cured physical properties, but 1-zoii part of dicyandiamide and 2 to 6 parts of masterbatch type curing agent are mixed per 100 parts by weight of epoxy resin.
It is in the range of 0 parts by weight.

In the composition of the present invention, reactive diluents, fillers, B) materials and other additives can be used in combination depending on the purpose, and if necessary, a solvent can also be used.

Examples of base materials used to obtain the prepreg include carbon fibers, glass fibers, mica, asbestos, aromatic polyamide fibers, woven fabrics and nonwoven fabrics thereof, and even paper.

In obtaining prepreg using the festival of the present invention,
In order to speed up the impregnation rate, the viscosity of the face can be lowered by heating it to 40°C to 90°C, and either the usual method, ie, immersing the base material in the face, or applying it to the entire face of the base material and applying a predetermined amount of The composition may be applied.

After that, the fiber reinforced material impregnated with Fes was further heated to 10°C.
Is it partially heated by a hot air stove at 0 to 160℃? A hardening (B
- staging) to obtain prepreg.

(Effects of the Invention) The epoxy resin composition for prepreg of the present invention has a long pot life, as is clear from the Examples and Comparative Examples described later, and the prepreg impregnated with a fiber base material has a long pot life. , and the obtained cured product exhibits a very high Tg,
Can be used in a wide range of fields.

For example, carbon fiber reinforced plastics can be used in so-called premium sporting goods such as golf club shafts, tennis rackets, and fishing rods, in copper-clad laminates impregnated with glass or fibers, or in mica tapes and the aforementioned fiber base materials. , B-staged film adhesives, insulating materials, anti-corrosion tape for steel pipes 1? (Can be used for layered structures, etc.)

(Examples and Comparative Examples) The present invention will be explained below with reference to examples, but the scope of the present invention is not limited by these examples. Note that "parts" in the examples indicate parts by weight.

Reference Example 1 (Synthesis of compound (a) having a tertiary amino group) 3 moles of bisphenol A epoxy resin AER-330 (manufactured by Asahi Kasei Kogyo ■, epoxy weight 185) and 1.5 moles of 2-methylimidazole, After reacting in methanol and toluene at 80°C, the solvent was distilled off under reduced pressure to obtain a solid compound.

This was crushed to obtain powdered amine compound X with an average particle size of 5μ.
-1 was obtained.

Reference Example 2 (Synthesis of a compound having a bonding group, L Y * Z 'x) 0.00% per mole of diphenylmethane diisocyanate.
Polymer P was obtained by reacting 5 moles of hexamethylene diamine in advance, adding 0.75 moles of bisphenol A, and further reacting.

Reference Example 3 (Creation of a calibration curve) Using 2,3-dimethyl-2,3-dicyanobutane as a standard substance, the absorption band between 1630 and 1660 cm-” of this and the model compound (Ml) was compared with that of the model compound (Ml). A calibration curve was created that correlated the area with the area ratio of the 2220-2250 cm-'' absorption band of the standard material. The results are shown in FIG.

Similarly, the absorption band area of the model compound (M2) from 1680 to 1725 cm-'', the absorption band area of the model compound (M3) from 01730 to 1755 cm-'', and the absorption band of the standard substance from 2220 to 2250 cm-'' A calibration curve was created that correlates the area ratio of and the actual weight ratio.The results are also shown in Figure IV' (Figure IV').

In addition, for the measurement of the IR spectrum, JEOL's FT-
IR (JIR-1oo) t-use i7j.

Reference Example 4 (Synthesis of masterbatch type curing agent) The polymer PIF'ji obtained in Reference Example 2 was dissolved in a mixed solvent of 992 xylene/methanol (1/1). To this solution, 50 f'i of 1-cyanoethyl-2-phenylimidazole (2PZ-CN), which had been previously ground to an average size of 5μ, was added, and after stirring at 25°C for 5 minutes, it was immediately subjected to p-filtration. + from door to door and the cake at 50℃ for 5 to 106
Next, the mixed solvent was evaporated under reduced pressure of Hg. At that time, when the nonvolatile content in the P liquid was measured, it was found to be 0.3% by weight, and the remaining 0.7% by weight was attached to the 2PZ-CN. I took 10f and added A to this.
20 f of ER-331 (bisphenol A type epoxy resin, manufactured by Asahi Kasei ■, epoxy fi189) was added and mixed uniformly using a triple roll to obtain a masterbatch type curing agent H-13Of. The viscosity of the nine master patch type hardeners (-1) obtained was 220,000 cps (25°C).The viscosity after being left in an atmosphere at 40°C for one week was 25.
0,000 Cp8, and there was almost no change in viscosity.
31120f t-Additionally, using three rolls, 12
Mixing was carried out at a discharge rate of 0 f/min to obtain a blended product F-1.

Compound F-1 was left at 50° C. and changes in viscosity were examined.

The initial viscosity of the formulation was 190° at 25°C. The viscosity after one week at 50°C is 250 voids.
The viscosity multiple was 1.32 times 90, and when the gelation time of compound F-1 at 120°C was investigated using the stroke curing method on a hot plate, it was found that it could be cured in 210 seconds. I found out something.

Reference Example 5 (Synthesis of masterbatch type curing agent) In a 1 t separable flask equipped with a stirrer and a temperature sensor, AE
Powder amine compound X-12001 to R-33140Of
After adding 5 liters of water and mixing uniformly, tolylene di incyanate (TDI) was added to give 40 liters of water.
When the reaction was continued for 2 hours while stirring at °C, the remaining TDI was 0.1 f or less, and masterbatch type curing agent H-2 was obtained.

(Analysis of masterbatch type curing agent) Masterbatch type curing agent H-215P'f: Xylene 1
When mixed with 00f and left for one day and night, components insoluble in xylene precipitated. This precipitate was separated and a 5.6f precipitate was obtained.

After drying the xylene from the oral fluid under reduced pressure, the remaining viscous liquid was identified as υAER-331 by IR analysis and epoxy equivalent measurement using the KI-HO2 method.

Meanwhile, the precipitate was dried under reduced pressure at 40°C to obtain a sample for analysis. In this analytical sample 3.32, 2.3-dimethyl and 2.3-dicyanobutane 10179 were added as standard substances.
After adding gold and grinding and mixing in a mortar, the heated mixture was heated to 50 ml.
The mixture was crushed with K B of η, and tablets with a diameter of 8 uφ were prepared using a tablet molding machine.

Using this tablet, JIR-Zoo type F manufactured by Japan 1piko
All infrared spectra were obtained using a T-IR measuring device.

Among the obtained figures, the concentration of the bonding group ■ was determined using a calibration line prepared in advance from the spectrum diagram in the infrared wavelength region of 1500 to 180 (Iyrl-1).
ameq/Kf - powdered amine compound and 7? -016
Wavelength range from 80 to 1725 cm-” and 1730-
The absorption in the wavelength region of 1755m-' was determined in exactly the same way, and the bonding group (7) and bonding group @) were found to be 2.
s me (1/Kg, 1 s meq/Kg.

This curing agent H-230j', APR-3311001F
and Ebome) B-002 (Yuka Shell Co., Ltd. hardening agent) 4
01 was added and cured at 25°C to prepare a sample for electron microscopy. The sample was sliced, and a cross section was photographed using a transmission electron microscope, and is shown in FIG. It can be seen from FIG. 2 that a shell is formed.

Examples 1 to 8 Epoxy resin AER-331L (Asahi Kasei Kogyo (9) bisphenol A type diglycidyl ether, epoxy resin:
1 = 189), dicyandiamide with an average particle size of 8 μm and the masterbatch type curing agent H-2 obtained in Reference Example 5.
All additions shown in 1 were added and kneaded with three rolls to obtain a festival composition.

Take out a part of the festival and heat it at 60℃. ;! The viscosity was measured immediately and after 6 hours, and
was evaluated at 50°C. The viscosity was measured using a BH type viscometer.

No precipitation of dicyandiamide was observed in any composition. The gelation time was defined as the torque rise time measured by a culastometer.

The fabric was heated to 60°C, impregnated into a glass nonwoven fabric, and heated in a hot air oven at 140°C for 8 minutes to obtain a prepreg. Cut out a part of this sample and heat it at 25℃ for 1 hour.
The condition of the prepreg was evaluated by touch after being left for several months. After curing this prepreg at 140°C for 30 minutes under pressure and heat of 30 Ky/cM, the sample was cut out diagonally to the weave of the glass fiber, and heated at a heating rate of 3°C/- using a rheopipron type. Tg was determined as σIll. Conclusion! V! , are shown in Table-1.

Comparative Examples 1 to 6 In place of the master patch type curing agent 11-2 of Reference Example 5, the conventionally known dicyandiamide (1) was used.
'1 N conversion accelerator DCMU (3-(3,4-d-;
, chlor.

phenyl )-1a 1-di math)'1
urea), PMU (3-phenyl-1)
1-di methyl urea) and BDM
A (Benzyl Di methyl amino
) and a composition using dicyandiamide having an average particle size of 70 μm were evaluated in the same manner as in the examples. Further, a prepreg was obtained using this composition in the same manner as in the example. The results are shown in Table-1.

Margin below

[Brief explanation of the drawing]

Figure 1 shows the weight ratio and IR of the model compound to the standard substance.
It is a graph which shows the relationship of the area ratio of a chart. FIG. 2 is an electron micrograph showing the particle structure (new surface) of curing agent (I) obtained in Reference Example 5. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] In an epoxy resin composition consisting of an epoxy resin and its curing agent system, the curing agent system contains (i) 1 to 20 parts by weight of dicyandiamide and (
ii) has at least one tertiary amino group in one molecule, but has no primary or secondary amino groups, and has a wave number of 1630 to 1
A powdery amine compound (A) having at least on its surface a bonding group (X) that absorbs infrared rays of 680 cm^-^1 and a bonding group (Y) that absorbs infrared rays of wave number 1680 to 1725 cm^-^1 as a core. and a curing agent (
I) and 10 parts by weight of the above curing agent (I).
Masterbatch type curing agent for one-component epoxy resin consisting of ~50,000 parts by weight of epoxy resin (B) 2-60
Epoxy resin composition for prepreg characterized by parts by weight