JP2023142053A - Epoxy resin composition, curable composition, cured product, prepreg, and composite material - Google Patents

Abstract

To provide an epoxy resin composition which imparts excellent impact strength to a cured product.SOLUTION: The epoxy resin composition contains: a bisphenol type epoxy resin (A) which has an epoxy equivalent in the range of 180-700 and is represented by general formula (1); and a biphenol type resin (B) which has an epoxy equivalent in the range of 900-10,000 and is represented by general formula (3). The ratio (Wa)/(Wb) of the weight Wa of the bisphenol type epoxy resin (A) to the weight Wb of the biphenol type resin (B) is 70/30-90/10.SELECTED DRAWING: None

Description

The present invention relates to epoxy resin compositions, curable compositions, cured products, prepregs, and composite materials.

Epoxy resins are widely used in fields such as electrical/electronic parts and structural materials due to their workability and the excellent electrical properties, heat resistance, adhesiveness, and moisture resistance (water resistance) of their cured products (for example, patent documents 1).

Patent No. 5348740

Since epoxy resins and their cured products have the above-mentioned excellent properties, their use as materials for parts of automobiles, drones, and nursing care robots has been considered in recent years. In these applications, higher impact resistance strength is required because they are expected to be used in environments where they are subject to impact.
An object of the present invention is to provide an epoxy resin composition that imparts excellent impact strength to its cured product.

The present inventor has arrived at the present invention as a result of studies to achieve the above object.
That is, the present invention provides a bisphenol type epoxy resin (A) represented by the following general formula (1) having an epoxy equivalent in the range of 180 to 700, and a bisphenol type epoxy resin (A) represented by the following general formula (3) having an epoxy equivalent in the range of 900 to 10,000. ), and the ratio (Wa)/(Wb) of the weight Wa of the bisphenol-type epoxy resin (A) to the weight Wb of the biphenol-type resin (B) is 70/30. 90/10; a curable composition containing the epoxy resin composition and a curing agent and/or a curing accelerator; a cured product obtained by curing the curable composition; A prepreg containing a synthetic composition and reinforcing fibers; a composite material obtained by curing the prepreg.

[In the formula, R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ² is represented by the following general formulas (2-1) to (2- 7), where n is the number average number of moles of groups represented by the following general formula (2A) per molecule of bisphenol resin (A) in the epoxy resin composition. Yes, the number is from 0.1 to 10. ]

[In the formula, R ³ is each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. ]

[In the formula, R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ² is represented by the above general formulas (2-1) to (2- 7). ]

[Wherein, Q is a group represented by the following general formula (4), X is a structural moiety represented by the following general formula (5), k is a number from 1 to 5, and Y is hydrogen an atom or a glycidyl group. ]

[In the formula, R ⁴ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ⁵ is an alkylene group having 2 to 6 carbon atoms, m represents the number of moles of R ⁵ O or OR ⁵ added, each independently being a number from 1 to 7; ]

[In the formula, R ⁶ is a divalent aliphatic hydrocarbon group having 2 to 18 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. It is a hydrogen group. ]

According to the present invention, it is possible to provide an epoxy resin composition that imparts excellent impact strength to its cured product.

<Epoxy resin composition>
The epoxy resin composition of the present invention comprises a bisphenol type epoxy resin (A) represented by the general formula (1) having an epoxy equivalent of 180 to 700, and a general formula (A) having an epoxy equivalent of 900 to 10,000. 3) contains a biphenol type resin (B) represented by.
The bisphenol type epoxy resin (A) is represented by the following general formula (1). In the following, "bisphenol type epoxy resin (A)" is also referred to as "component (A)."

In the general formula (1), R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a straight-chain or branched propyl group, and a straight-chain or branched butyl group. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a straight-chain or branched propoxy group, and a straight-chain or branched butoxy group. Preferably, R ¹ is a hydrogen atom.

R ² is a structural moiety represented by any of the following general formulas (2-1) to (2-7). In general formula (2-2), each R ³ is independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms and the alkoxy group having 1 to 4 carbon atoms include the same groups as exemplified for R ¹ .
R ² is preferably a structural moiety represented by general formula (2-2), more preferably a structural moiety in which R ³ in general formula (2-2) is a methyl group.

n in the general formula (1) is the number average number of moles of the group represented by the general formula (2A) per molecule of all bisphenol resins (A) in the epoxy resin composition. n is a number from 0.1 to 10, and may be a decimal number. The group represented by general formula (2A) is the group in parentheses in general formula (1). n is preferably 0.1 to 9.0, more preferably 0.1 to 6.0. An example where n is a decimal number will be explained. For example, component (A) is a compound in which the number of groups represented by general formula (2A) in general formula (1) is 1, and a group represented by general formula (2A) in general formula (1). In the case of an embodiment containing a compound in which the number of The number of groups is 0.1.
The method of calculating n will be explained. For example, component (A) is a compound in which the number of moles of the group represented by general formula (2A) in general formula (1) is n1, and a compound represented by general formula (2A) in general formula (1). In the case of an embodiment containing a compound in which the number of moles of the group is n2 at a 1:p (mole ratio), the amount of the compound of the general formula (2A) per molecule of the bisphenol type epoxy resin (A) represented by the general formula (1) The number average mole number n of the group represented by can be calculated based on the following formula.
n=(1×n1+p×n2)/(1+p)

In the general formula (2A), R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ² is the general formula (2-1) to It is a structural site represented by any of (2-7). In formula (2A), R ¹ and R ² are the same as R ¹ and R ² in general formula (1), respectively.

The bisphenol type epoxy resin (A) represented by the general formula (1) has an epoxy equivalent in the range of 180 to 700. When the epoxy equivalent of the bisphenol-type epoxy resin (A) is within the above range, excellent impact resistance can be exhibited in the cured product and composite material of the curable composition containing the epoxy resin composition. If the epoxy equivalent is less than 180 or more than 700, the impact resistance of the cured product may be insufficient. The epoxy equivalent of the bisphenol type epoxy resin (A) is preferably 200 to 700, more preferably 250 to 600.

In the present invention, the epoxy equivalent of an epoxy resin refers to the mass of the resin containing 1 equivalent of epoxy groups, and can be measured by the method specified in JISK 7236.
When using two or more types of epoxy resins, the epoxy equivalent of a mixture containing two or more types of epoxy resins can be calculated as follows.
For example, when using W1g of epoxy resin 1 having an epoxy equivalent of EE1 and W2g of epoxy resin 2 having an epoxy equivalent of EE2, the epoxy equivalent EEm of the mixture of epoxy resin 1 and epoxy resin 2 can be calculated by the following formula (Z).
EEm=(W1+W2)/{(W1/EE1)+(W2/EE2)} (Z)

In the present invention, one type of bisphenol type epoxy resin (A) may be used alone, or two or more types may be used. When two or more types of bisphenol type epoxy resins (A) are used, the epoxy equivalent of the mixture of two or more types of bisphenol type epoxy resins may be in the range of 180 to 700, and the epoxy equivalent of the mixture is outside the above range. It may also contain a bisphenol type epoxy resin.

The bisphenol-type epoxy resin (A) can be manufactured using various bisphenol compounds, epihalohydrin, and the like. Specific production methods include, for example, a method in which a diglycidyl ether compound obtained by reacting a bisphenol compound and epihalohydrin is further reacted with a bisphenol compound (Method 1), and a method in which a bisphenol compound and epihalohydrin are reacted directly. Examples include a method (method 2) for obtaining the target epoxy resin. Method 1 is preferred because the reaction is easy to adjust and the epoxy equivalent of the resulting epoxy resin (A) is easy to adjust.

As the bisphenol compound used in method 1 or 2, for example, a compound represented by the following general formula (1a) can be used. As the epihalohydrin, epichlorohydrin or the like can be used.

In formula (1a), R ¹ and R ² are respectively the same as R ¹ and R ² in general formula (1). The compound represented by general formula (1a) can be selected depending on the type of the target bisphenol-type epoxy resin (A) [compound represented by general formula (1)].

The bisphenol type epoxy resin (A) is preferably a bisphenol A epichlorohydrin condensate. Commercially available bisphenol epoxy resins may be used. Commercially available bisphenol-type epoxy resins (A) include "jER1004", "jER1002", "jER1001", and "jER828" manufactured by Mitsubishi Chemical Corporation.

The biphenol type resin (B) is a compound represented by the following general formula (3). In the following, "biphenol type resin (B)" is also referred to as "component (B)."

In the general formula (3), Q is a group represented by the following general formula (4).

In the general formula (4), R ⁴ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a straight-chain or branched propyl group, and a straight-chain or branched butyl group. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a straight-chain or branched propoxy group, and a straight-chain or branched butoxy group. Preferably, R ⁴ is a hydrogen atom.

In the general formula (4), R ⁵ is an alkylene group having 2 to 6 carbon atoms. Examples of the alkylene group having 2 to 6 carbon atoms include a methylene group, an ethylene group, a straight-chain or branched propylene group, a straight-chain or branched butylene group, a straight-chain or branched pentylene group, and a straight-chain or branched pentylene group. Examples include hexylene groups. R ⁵ is preferably a linear or branched propylene group. When there is a plurality of R ⁵ (m is 2 or more), R ⁵ may be the same or different.

m in the general formula (4) represents the number of moles of R ⁵ O or OR ⁵ added, each independently being a number from 1 to 7. The two m's are the number of moles of R ⁵ O added and the number of moles of OR ⁵ added per molecule of the biphenol resin (B) represented by the general formula (3), respectively, and may be decimal numbers. The two m's are preferably each independently an integer of 1 to 7, and the total of the two m's is more preferably 2 to 14.

X in general formula (3) is a structural moiety represented by general formula (5) below.

In the general formula (5), R ⁶ is a divalent aliphatic hydrocarbon group having 2 to 18 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a divalent alicyclic hydrocarbon group having 6 to 18 carbon atoms. It is an aromatic hydrocarbon group.

Examples of divalent aliphatic hydrocarbon groups having 2 to 18 carbon atoms include divalent saturated aliphatic hydrocarbon groups having 2 to 18 carbon atoms that may have branches (ethylene group, n-propylene group, isopropylene group, Propylene group, n-butylene group, isobutylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, n-undecylene group, n-dodecylene group , n-tridelene group, n-tetradecylene group, n-pentadecylene group, n-hexadecylene group, n-heptadecylene group, n-octadecylene group, etc.) and a branched alkylene group having 2 to 18 carbon atoms. divalent aliphatic unsaturated hydrocarbon groups (for example, straight-chain or branched aliphatic unsaturated hydrocarbon groups such as ethenylene group, propenylene group, butenylene group, hexenylene group, decenylene group, undecenylene group, tetradecenylene group, and octadecenylene group) alkenylene group), etc.
Examples of divalent alicyclic hydrocarbon groups having 3 to 18 carbon atoms include cycloalkylene groups having 3 to 18 carbon atoms (cyclopropylene group, cyclobutylene group, cyclopentylene group, cyclohexylene group, etc.), carbon atoms Cycloalkenylene groups having 3 to 18 carbon atoms (cyclopropenylene group, cyclobutenylene group, cyclopentenylene group, cyclohexenylene group, etc.), bicyclic alkylene groups having 3 to 18 carbon atoms (decahydronaphthylene group, etc.), etc. Can be mentioned. The divalent alicyclic hydrocarbon group may be a group having a substituent (for example, an aliphatic hydrocarbon group). When the divalent alicyclic hydrocarbon group has a substituent, the total number of carbon atoms in the substituent and the cyclic portion may be 3 to 18. Examples of the substituent include saturated or unsaturated aliphatic hydrocarbon groups having 1 to 10 carbon atoms, and the substituent may be linear or branched. Substituents include alkyl groups having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, butyl group, isopropyl group, pentyl group, hexyl group, heptyl group, octyl group, etc.), alkenyl groups having 1 to 10 carbon atoms. (ethenyl group, propenyl group, butenyl group, methylbutenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, etc.).
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms include a phenylene group, a naphthylene group, and a biphenylene group. The divalent aromatic hydrocarbon group may be a group having a substituent (for example, an aliphatic hydrocarbon group, etc.). When the divalent aromatic hydrocarbon group has a substituent, the total number of carbon atoms in the substituent and the aromatic ring portion may be 6 to 18. Examples of the substituent include the same substituents as those exemplified as substituents for the alicyclic hydrocarbon group.
R ⁶ is preferably a divalent alicyclic hydrocarbon group having 5 to 18 carbon atoms, a divalent cycloalkenylene group having an aliphatic hydrocarbon group as a substituent, and a divalent cycloalkenylene group having an aliphatic hydrocarbon group as a substituent. A cyclohexynylene group which is preferably a divalent cycloalkylene group and has an alkyl group or alkenyl group having 1 to 4 carbon atoms (for example, one or more groups selected from methyl group and methylpropenyl group) as a substituent and cyclohexenylene group are more preferable.

k in general formula (3) is a number from 1 to 5. k is preferably 1-4, more preferably 1-3. Y in general formula (3) is a hydrogen atom or a glycidyl group. Y is preferably a glycidyl group.

The biphenol resin (B) represented by the general formula (3) has an epoxy equivalent weight in the range of 900 to 10,000. When the epoxy equivalent of the biphenol resin (B) is within the above range, excellent impact resistance can be exhibited in the cured product and composite material obtained by curing the epoxy resin composition. If the epoxy equivalent is less than 900 or more than 10,000, the impact resistance may be insufficient. The epoxy equivalent of the biphenol type resin (B) is preferably 950 to 9,800, more preferably 1,000 to 9,000.

In the present invention, as component (B), one type of compound represented by general formula (3) may be used alone, or two or more types may be used. When two or more compounds represented by the general formula (3) are used, the epoxy equivalent of the mixture of the two or more compounds may be in the range of 900 to 10,000, and the epoxy equivalent of the mixture is outside the above range. It may also contain a biphenol type resin.

The biphenol type resin (B) is, for example, a biphenol alkylene oxide (AO) adduct obtained by adding an alkylene oxide (AO) having 2 to 6 carbon atoms to a biphenol compound represented by the following general formula (3a). a step (step 1) of obtaining a glycidylated product of the AO adduct of biphenol by glycidyl etherification of the AO adduct of biphenol, and a step (step 2) of obtaining a glycidylated product of the AO adduct of biphenol; can be obtained by sequentially performing the steps of introducing (step 3).

R ⁴ in general formula (3a) is the same as R ⁴ in general formula (4).

In step 1, the alkylene oxide [alkylene oxide having 2 to 6 carbon atoms to be added to the compound represented by general formula (3a)] constituting the AO adduct of biphenol is ethylene oxide (hereinafter abbreviated as EO). ), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide, 1,2-pentylene oxide, and 1,2-hexylene oxide. These may be used alone or in combination of two or more. The AO is preferably an alkylene oxide having 2 to 4 carbon atoms, and more preferably PO.

In step 2, when the AO adduct of biphenol is glycidyl etherified, a glycidylated product of the AO adduct of biphenol can be obtained by reacting the AO adduct of biphenol with epichlorohydrin.

In step 3, the structure represented by general formula (5) is introduced into the molecule by a structure represented by -R ⁶ - (R ⁶ is R ⁶ in general formula (5), and a divalent (aliphatic hydrocarbon group having 2 to 18 carbon atoms, divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms, or divalent aromatic hydrocarbon group having 6 to 18 carbon atoms), etc. This can be done by Compounds having a structure represented by R ⁶ in the molecule include acid anhydrides having a divalent group represented by R ⁶ in the molecule [for example, 3,4-dimethyl-6-(2-methyl- (1-propenyl)-4-cyclohexene-1,2-dicarboxylic anhydride, 4-methylhexahydrophthalic anhydride, tetrahydromethyl phthalic anhydride, methylbutenyltetrahydrophthalic anhydride, etc.). A catalyst may be used when introducing the structure represented by general formula (5). Examples of the catalyst include trivalent aliphatic amines (eg, triethylamine, etc.).

The epoxy equivalent of the epoxy resin composition of the present invention is preferably in the range of 250 to 600, more preferably 255 to 580, from the viewpoint of excellent impact resistance.

In the epoxy resin composition of the present invention, the ratio (Wa)/(Wb) of the weight Wa of the bisphenol-type epoxy resin (A) to the weight Wb of the biphenol-type epoxy resin (B) is 70/30 to 90/10. . When the ratio (Wa)/(Wb) of the weight Wa of the bisphenol-type epoxy resin (A) to the weight Wb of the biphenol-type epoxy resin (B) is within the above range, the curable composition containing the epoxy resin composition is cured. Can exhibit excellent impact resistance in objects. When (Wa)/(Wb) is less than 70/30 or more than 90/10, the impact resistance of the cured product of the curable composition containing the epoxy resin composition may be insufficient.
The epoxy resin composition of the present invention can be used as a curable composition etc. in combination with a curing agent and/or a curing accelerator.

<Curable composition>
The curable composition of the present invention contains the epoxy resin composition of the present invention, and a curing agent and/or a curing accelerator.

Examples of the curing agent (C) and curing accelerator (D) include polyamine compounds, amide compounds, acid anhydrides, phenolic hydroxyl group-containing resins, phosphorus compounds, imidazole compounds, imidazoline compounds, urea compounds, and organic acid metal salts. , Lewis acids and amine complex salts. Hereinafter, the "curing agent (C)" may be referred to as "component (C)", and the "curing accelerator (D)" may be referred to as "component (D)". Specific examples of these include those described in Japanese Patent No. 6721855. An example is shown below.

Examples of polyamine compounds include aliphatic amine compounds (for example, trimethylene diamine, ethylene diamine, etc.), alicyclic and heterocyclic amine compounds (for example, piperidine, piperazine, menthanediamine, isophorone diamine, methylmorpholine, ethylmorpholine, etc.) , aromatic amine compounds (eg, phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, pyridine, etc.), and modified amine compounds (epoxy compound-added polyamines, etc.).
Examples of amide compounds include dicyandiamide and polyamide amines (carboxylic acid compounds such as aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid, fatty acids and dimer acids); and those obtained by reacting with polyamines having polyoxyalkylene chains, etc.).
Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples include acids.
Examples of the phenolic hydroxyl group-containing resin include phenol novolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, and dicyclopentadiene phenol addition type resin.
Examples of phosphorus compounds include alkyl phosphines such as ethylphosphine and butylphosphine, primary phosphines such as phenylphosphine; dialkylphosphines such as dimethylphosphine and dipropylphosphine; secondary phosphines such as diphenylphosphine and methylethylphosphine; trimethylphosphine, Examples include tertiary phosphines such as triethylphosphine and triphenylphosphine.
Examples of the imidazole compound include imidazole, methylimidazole, and ethylimidazole.
Examples of the imidazoline compound include 2-methylimidazoline and 2-phenylimidazoline.
Examples of urea compounds include aromatic dimethylurea compounds (p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-N,N-dimethylurea, and N-(3-chloro-4-methylphenyl)-N',N'-dimethylurea, etc.).

As the curing agent (C) and curing accelerator (D), commercially available ones may be used. Commercially available curing agents include dicyandiamide [DICY7, manufactured by Mitsubishi Chemical Corporation] and aromatic dimethylurea [U-CAT 3512T, manufactured by San-Apro Co., Ltd.].

The curing agent (C) is preferably at least one compound selected from the group consisting of aromatic amine compounds, acid anhydrides, imidazole compounds, and dicyandiamide, and more preferably contains dicyandiamide.
The curing accelerator (D) preferably contains a urea compound, more preferably aromatic dimethylurea.

When the curing agent (C) is used in the present invention, the amount used is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, based on the weight of the curable composition.
When using a curing agent having a functional group capable of reacting with an epoxy group as the curing agent (C), the epoxy resin component [(A) component, (B) component and other epoxy resin (E) ( The curing agent is preferably used so that the amount of functional groups in the curing agent is in the range of 0.4 to 1.0 mol per 1 mol of the epoxy group in the curing agent (details will be described later).

In the present invention, when the curing accelerator (D) is used, the amount used is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, based on the weight of the curable composition.

The curable composition of the present invention may use epoxy resins other than the components (A) and (B). Other epoxy resins (E) [also referred to as component (E)] include, for example, novolac type epoxy resins such as phenol novolak type, naphthol novolak type, cresol novolak type, phenol-cresol cocondensed novolak type, urethane-modified epoxy resins, and Examples include triphenylmethane type epoxy resin.

The curable composition of the present invention may contain components other than components (A) to (E). Other ingredients include organic solvents, ultraviolet absorbers, antioxidants, silicone additives, fluorine additives, flame retardants, plasticizers, silane coupling agents, organic beads, inorganic fine particles, inorganic fillers, and rheology control agents. , defoamers, antifogging agents, coloring agents, and the like. These components can be added in arbitrary amounts depending on desired performance.

The curable composition of the present invention can be prepared by mixing the (A) component, (B) component, (C) component and/or (D) component, and if necessary, the (E) component and the other components mentioned above, using a pot mill or a ball mill. , a bead mill, a roll mill, a homogenizer, a super mill, a homodisper, an all-purpose mixer, a Banbury mixer, a kneader, and the like.

<Cured product>
The cured product of the present invention is obtained by curing the curable composition of the present invention. The cured product of the present invention can be produced, for example, by placing the curable composition prepared by the method described above into a mold of a desired shape and heating it at 120 to 140° C. for 1 to 3 hours. Temperature conditions, heating time, etc. when producing a cured product can be appropriately selected in consideration of the type and amount of resin contained in the composition.

Since the cured product of the curable composition of the present invention has excellent impact resistance, it is suitable, for example, as a material for parts of products that are expected to be used in environments subject to impact. Examples of devices that are expected to be used in environments that are subject to impact include cars, drones, and nursing care robots. In addition to the above-mentioned uses, the cured product of the present invention may also be used in paints, coating agents, molding materials, insulating materials, sealants, sealants, fiber binding agents, and the like.

<Prepreg>
The prepreg of the present invention contains the curable composition of the present invention and reinforcing fibers.
The prepreg of the present invention is a prepreg made of the curable composition of the present invention as a matrix resin. The prepreg of the present invention may contain a catalyst, if necessary, in addition to the reinforcing fibers and the curable composition of the present invention.
Examples of the catalyst include known curing agents and curing accelerators for epoxy resins, such as those described in JP-A No. 2005-213337.

Examples of reinforcing fibers include fiber bundles obtained by treating fibers with a fiber sizing agent and textile products obtained by processing the fiber bundles. As the fiber sizing agent, known ones and commercially available ones can be used. Commercially available fiber sizing agents include, for example, the "Chemitylene" series manufactured by Sanyo Chemical Industries, Ltd.

Fibers to be treated with fiber sizing agents include known fibers such as glass fibers, carbon fibers, aramid fibers, ceramic fibers, metal fibers, mineral fibers, rock fibers, and slag fibers (see International Publication No. 2003/47830). etc.). From the viewpoint of the strength of the composite material, carbon fibers are preferred. One type of fiber may be used alone or two or more types may be used in combination.

Examples of methods for treating fibers include spraying methods and dipping methods. The amount (% by weight) of the fiber sizing agent attached to the fibers is preferably 0.05 to 5% by weight, more preferably 0.1 to 3.0% by weight, based on the weight of the fibers. Within this range, the composite strength is even better.

Textile products are produced by processing the aforementioned fiber bundles, and include woven fabrics, knitted fabrics, nonwoven fabrics (felt, mats, paper, etc.), chopped fibers, milled fibers, and the like.

The prepreg of the present invention can be produced by a method in which the curable composition of the present invention is impregnated into fibers by hot melting (melting temperature: 60 to 150°C), or by a method in which the curable composition of the present invention is impregnated into fibers, or by a method in which the curable composition of the present invention is impregnated into fibers (acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, and ethyl acetate). It can be produced by a method such as impregnating fibers with the curable composition of the present invention diluted with (etc.). When a method using a solvent is adopted, it is preferable to dry the prepreg to remove the solvent.

The weight ratio of the curable composition and fibers (curable composition/fiber) is preferably 10/90 to 90/10, more preferably 20/80 to 70/30, particularly Preferably it is 30/70 to 60/40. When containing a catalyst, the content (wt%) of the catalyst is preferably 0.01 to 10, more preferably 0.1 to 5, particularly preferably 0.01 to 10, based on the curable composition, from the viewpoint of molded body strength etc. is 1 to 3.

<Composite materials>
The composite material of the present invention is obtained by curing the prepreg of the present invention. The composite material can be obtained, for example, by thermoforming the prepreg of the present invention and curing it. Although curing does not have to be complete, it is preferable that the composite material be cured to an extent that it can maintain its shape. The method of thermoforming is not particularly limited, and examples include filament winding method (a method in which the material is wrapped around a rotating mandrel under tension and heat formed), press molding method (a method in which prepreg sheets are laminated and heat formed), and autoclave. (a method in which a prepreg sheet is heated and pressed against a mold by applying pressure) and a method in which chopped fibers or milled fibers are mixed with a matrix resin and injection molded.

The present invention will be further explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
<Production Example 1: Production of PO adduct (b11) of 4,4'-dihydroxybiphenyl>
In a pressure-resistant reaction vessel equipped with a stirrer, a heating/cooling device, and a dropping cylinder, 186.2 parts by weight (1 mole part) of a biphenol compound ("4,4'-dihydroxybiphenyl" [manufactured by Tokyo Chemical Industry Co., Ltd.]), 130.3 parts by weight of methyl ethyl ketone and 1 part by weight of potassium hydroxide were added, and the mixture was purged with nitrogen. The temperature was raised to 110°C, and 406 parts by weight (7 mol) of propylene oxide was added dropwise over 19 hours while adjusting the pressure to 0.5 MPa or less, and then aged at 110°C for 6 hours. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 85°C and -0.1 MPa to obtain a PO adduct of 4,4'-dihydroxybiphenyl (b11).

<Production Example 2: Production of glycidylated product (b12) of PO adduct of 4,4'-dihydroxybiphenyl>
151 parts by weight of the PO adduct of 4,4'-dihydroxybiphenyl (b11) produced in Production Example 1 and epichlorohydrin were placed in a reaction tank equipped with a stirring device, temperature control measures, and a wet grinder (attached to the outside of the reaction tank). 278 parts by weight and 30 parts by weight of cyclohexane were charged, the inside of the reaction tank was placed under a nitrogen atmosphere (oxygen concentration: 730 ppm), and 112 parts by weight of granular potassium hydroxide in a nitrogen atmosphere at 19°C was heated at 19 to 29°C for 5 hours. It was intermittently applied. Thereafter, the reaction mixture was aged at 25° C. to 29° C. for 5 hours to convert the above (b11) into glycidyl ether.
Next, after cooling the inside of the tank to 16°C, 370.4 parts by weight of water at 23°C was added in the range of 20 to 28°C, stirred for 0.5 hours, separated and left at 17°C for 0.5 hours, and then the lower layer (aqueous layer) was taken out, and 12 parts by weight of "Kyoward 600" (manufactured by Kyowa Chemical Industry Co., Ltd.; alkaline adsorbent) was added to the remaining upper layer (organic layer), and the mixture was stirred at 80° C. for 0.5 hour. After filtering using "Radiolite #700" (manufactured by Kyowa Chemical Industry Co., Ltd., diatomaceous earth filter aid), the temperature was raised to 110°C under reduced pressure (-0.1 MPa) to distill off the epichlorohydrin and cyclohexane mixture. A glycidylated product (b12) of the PO adduct of 4,4'-dihydroxybiphenyl was obtained.

<Production Example 3: Production of biphenol type resin (B-1)>
In a reaction tank equipped with a stirring device and a temperature control device, 706 parts of glycidylated product (b12) of PO adduct of 4,4'-dihydroxybiphenyl and 3,4-dimethyl-6-(2-methyl-1-propenyl) were added. )-4-Cyclohexene-1,2-dicarboxylic anhydride and 7 parts of triethylamine were charged, the inside of the reaction tank was set to a nitrogen atmosphere (oxygen concentration: 730 ppm), and the reaction was carried out at 100°C for 1 hour to form a biphenol type resin ( B-1) was obtained. The epoxy equivalent of the biphenol type resin (B-1) was measured by the method specified in JIS K7236. Resin (B-1) is a resin represented by general formula (3) {in general formula (3), k is 1, Q is a divalent group in which PO is added to the terminal of a biphenylene group [PO addition mole The number is 7 per Q (total of two m is 7)], Y is a hydrogen atom, k in general formula (3) is 1, and Q is 2 with PO added to the end of the biphenylene group. valent group [the number of moles of PO added is 7 per Q (total of two m is 7)], and a compound where Y is a glycidyl group}.

<Production Example 4: Production of biphenol type resin (B-2)>
In a reaction tank equipped with a stirring device and a temperature control device, 1412 parts of glycidylated product (b12) of PO adduct of 4,4'-dihydroxybiphenyl and 3,4-dimethyl-6-(2-methyl-1-propenyl) were added. )-4-Cyclohexene-1,2-dicarboxylic anhydride (1322 parts) and triethylamine (14 parts) were charged, the inside of the reaction tank was set to a nitrogen atmosphere (oxygen concentration: 730 ppm), and the reaction was carried out at 100°C for 1 hour to form a biphenol-type epoxy resin. (B-2) was obtained. The epoxy equivalent of the biphenol type resin (B-2) was measured by the method specified in JIS K7236. Resin (B-2) is a resin represented by general formula (3) {in general formula (3), k is 2 and Q is a bivalent group in which PO is added to the terminal of a biphenylene group [PO addition mole The number is 7 per Q (the total of two m is 7)], Y is a hydrogen atom, k in general formula (3) is 2, and Q is 2 with PO added to the end of the biphenylene group. valent group [the number of moles of PO added is 7 per Q (total of two m is 7)], and a compound where Y is a glycidyl group}.

<Production Example 5: Production of biphenol type resin (B-3)>
In a reaction tank equipped with a stirring device and a temperature control device, 4237 parts of glycidylated product (b12) of PO adduct of 4,4'-dihydroxybiphenyl and 3,4-dimethyl-6-(2-methyl-1-propenyl) were added. ) -4-Cyclohexene-1,2-dicarboxylic acid anhydride (5286 parts) and triethylamine (21 parts) were charged, the inside of the reaction tank was set to a nitrogen atmosphere (oxygen concentration: 730 ppm), and the reaction was carried out at 100°C for 1 hour to form a biphenol type epoxy resin. (B-3) was obtained. The epoxy equivalent of the biphenol type resin (B-3) was measured by the method specified in JIS K7236. Resin (B-3) is a resin represented by general formula (3) {in general formula (3), k is 3 and Q is a divalent group in which PO is added to the terminal of a biphenylene group [PO addition mole The number is 7 per Q (total of 2 m is 7)], Y is a hydrogen atom, k in general formula (3) is 7, and Q is 2 with PO added to the end of the biphenylene group. valent group [the number of moles of PO added is 7 per Q (total of two m is 7)], and a compound where Y is a glycidyl group}.

<Production Example 6: Production of biphenol type resin (B-4)>
In Production Example 4, 938 parts of tetrahydromethylphthalic anhydride was used instead of 1322 parts of 3,4-dimethyl-6-(2-methyl-1-propenyl)-4-cyclohexene-1,2-dicarboxylic anhydride. Except for the above, the same operation as in Production Example 4 was performed to obtain a biphenol type resin (B-4). The epoxy equivalent of the biphenol type resin (B-4) was measured by the method specified in JIS K7236. Resin (B-4) is a resin represented by the general formula (3) {in the general formula (3), k is 2 and Q is a divalent group in which PO is added to the terminal of a biphenylene group [PO addition mole The number is 7 per Q (the total of two m is 7)], Y is a hydrogen atom, k in general formula (3) is 2, and Q is 2 with PO added to the end of the biphenylene group. valent group [the number of moles of PO added is 7 per Q (total of two m is 7)], and a compound where Y is a glycidyl group}.

<Production Example 7: Production of biphenol type resin (B-5)>
In Production Example 4, 949 parts of 4-methylhexahydrophthalic anhydride was used instead of 1322 parts of 3,4-dimethyl-6-(2-methyl-1-propenyl)-4-cyclohexene-1,2-dicarboxylic anhydride. A biphenol type epoxy resin (B-5) was obtained by carrying out the same operation as in Production Example 4 except that . The epoxy equivalent of the biphenol type resin (B-5) was measured by the method specified in JIS K7236. Resin (B-5) is a resin represented by general formula (3) {in general formula (3), k is 2 and Q is a divalent group in which PO is added to the terminal of a biphenylene group [PO addition mole The number is 7 per Q (the total of two m is 7)], Y is a hydrogen atom, k in general formula (3) is 2, and Q is 2 with PO added to the end of the biphenylene group. valent group [the number of moles of PO added is 7 per Q (total of two m is 7)], and a compound where Y is a glycidyl group}.

<Examples 1 to 7 and Comparative Examples 1 to 2>
(Preparation of curable composition)
The types and amounts (parts by weight) of bisphenol-type epoxy resin (A), biphenol-type resin (B), curing agent (C), and curing accelerator (D) listed in Table 1 were mixed in a stirring defoaming machine (manufactured by THINKY Co., Ltd.). ARV-930TWIN) was used to mix at 1400 rpm and 100° C. for 3 minutes to obtain a curable composition.

Each component used in Examples and Comparative Examples is as follows.
The epoxy equivalents of the epoxy resins (A-1) to (A-3) were measured in the same manner as resin (B-1).
In the column "Epoxy equivalent of component (A)" and "Epoxy equivalent of component (B)" in Table 1, if one type of compound is used, enter the epoxy equivalent of the compound, and if two or more types When a compound is used, the epoxy equivalent of a mixture of two or more compounds is described. In the column "Epoxy equivalent of epoxy resin composition" in Table 1, the epoxy equivalent of the mixture of component (A), component (B), component (C), and component (D) is listed. The epoxy equivalent of the mixture was calculated using the above formula (Z).
(A-1): Bisphenol A epichlorohydrin condensate [“jER1002” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 650, n in general formula (1) is 3.0]
(A-2): Bisphenol A epichlorohydrin condensate [“jER1001” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 479, n in general formula (1) is 2.0]
(A-3): Bisphenol A epichlorohydrin condensate [“jER828” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 186, n in general formula (1) is 0.1]
(B-1): Biphenol type resin obtained in Production Example 3 (epoxy equivalent: 1029)
(B-2): Biphenol type resin obtained in Production Example 4 (epoxy equivalent: 2156)
(B-3): Biphenol type resin obtained in Production Example 5 (epoxy equivalent: 8817)
(B-4): Biphenol type resin obtained in Production Example 6 (epoxy equivalent: 2042)
(B-5): Biphenol type resin obtained in Production Example 7 (epoxy equivalent: 2046)
(C-1): Dicyandiamide [“DICY7” manufactured by Mitsubishi Chemical Corporation]
(D-1): Aromatic dimethylurea [“U-CAT 3512T” manufactured by San-Apro Co., Ltd.]

<Measurement of glass transition temperature and storage modulus of cured product>
The curable compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were placed in molds in which a silicone spacer with a thickness of 4 mm was placed between two SUS plates, and degassed at 100° C. under a reduced pressure of 10 mmHg. After that, it was heated and cured at 130° C. for 1 hour, and then processed with a diamond cutter into a test piece with a length of 30 mm, a width of 4 mm, and a thickness of 1 mm.
This test piece was subjected to tensile storage using a dynamic viscoelasticity measuring device [trade name "Rheogel-E4000", manufactured by UBM Co., Ltd.] according to the method specified in JIS-K7244-4, with 10 Hz vibration applied. The elastic modulus and tensile loss modulus were measured. The temperature at which the tensile loss coefficient calculated from the above-mentioned tensile storage modulus and tensile loss modulus is maximum was defined as the glass transition temperature, and that temperature was read.

<Evaluation of impact resistance of composite materials>
(1) Production of prepreg The curable compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were coated on release paper using a knife coater to produce a resin film. Carbon fibers treated with a sizing agent [800 tex fineness, 12,000 filaments, ``Chemitylene FS-6'' manufactured by Sanyo Chemical Industries, Ltd. is used as a sizing agent] are arranged in one direction in a sheet form. Created. Next, one sheet of the resin film was placed on each side of the carbon fiber treated with a sizing agent, and heated under pressure at a temperature of 85° C. and a pressure of 2 MPa to impregnate the thermosetting resin composition. Got prepreg.

(2) Evaluation of impact resistance The Charpy impact value of the composite material was measured by the following method.
A laminate was produced by laminating the unidirectional prepregs so that the fiber directions were in the same direction and the thickness was about 3 mm. The laminate was cured by heating and pressurizing in an autoclave at 135° C. and an internal pressure of 588 kPa for 2 hours to produce a unidirectional fiber-reinforced composite material.
A test piece with a thickness of 3±0.2 mm, a width of 10±0.2 mm, and a length of 80 mm was cut out from the fiber-reinforced composite material of each example obtained. Using the test piece, according to the method specified in JIS K7077 (1991), a Charpy impact test (no notch) was performed by applying a flatwise impact with a weight of 300 kg cm to measure the impact value (unit: kJ/m ² ). . The number of measurements was n=5 and the average value was calculated. The results are shown in Table 1. The larger the value, the better the impact resistance.

As shown in Table 1, the bisphenol type epoxy resin (A) represented by the general formula (1) has an epoxy equivalent of 180 to 700, and the general formula (3) has an epoxy equivalent of 900 to 10,000. containing a biphenol type resin (B) represented by, and the ratio (Wa)/(Wb) of the weight Wa of the bisphenol type epoxy resin (A) to the weight Wb of the biphenol type resin (B) is 70/30 ~ The cured product of the example using the 90/10 epoxy resin composition had better impact resistance than the comparative example. From these results, it was found that the present invention can provide an epoxy resin composition that imparts excellent impact resistance to a cured product.

Claims (8)

A bisphenol type epoxy resin (A) represented by the following general formula (1) having an epoxy equivalent in the range of 180 to 700, and a biphenol represented by the following general formula (3) having an epoxy equivalent in the range of 900 to 10,000. Contains a mold resin (B),
An epoxy resin composition in which the ratio (Wa)/(Wb) of the weight Wa of the bisphenol type epoxy resin (A) to the weight Wb of the biphenol type resin (B) is 70/30 to 90/10.

[In the formula, R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ² is represented by the following general formulas (2-1) to (2- 7), where n is the number average number of moles of groups represented by the following general formula (2A) per molecule of bisphenol resin (A) in the epoxy resin composition. Yes, the number is from 0.1 to 10. ]

[In the formula, R ³ is each independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. ]

[In the formula, R ¹ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ² is represented by the above general formulas (2-1) to (2- 7). ]

[Wherein, Q is a group represented by the following general formula (4), X is a structural moiety represented by the following general formula (5), k is a number from 1 to 5, and Y is hydrogen an atom or a glycidyl group. ]

[In the formula, R ⁴ is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R ⁵ is an alkylene group having 2 to 6 carbon atoms, m represents the number of moles of R ⁵ O or OR ⁵ added, each independently being a number from 1 to 7; ]

[In the formula, R ⁶ is a divalent aliphatic hydrocarbon group having 2 to 18 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. It is a hydrogen group. ] The epoxy resin composition according to claim 1, wherein the two m's in the general formula (3) are each independently an integer of 1 to 7, and the total of the two m's is 2 to 14. The epoxy resin composition according to claim 1 or 2, wherein the epoxy equivalent of the epoxy resin composition is in the range of 250 to 600. A curable composition comprising the epoxy resin composition according to any one of claims 1 to 3, and a curing agent and/or a curing accelerator. The curable composition according to claim 4, wherein the curing agent contains dicyandiamide. A cured product obtained by curing the curable composition according to claim 4 or 5. A prepreg comprising the curable composition according to claim 4 or 5 and reinforcing fibers. A composite material obtained by curing the prepreg according to claim 7.