JP2016069563A - Method for producing epoxy resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain: an epoxy resin excellent in low melt viscosity and solvent solubility; an epoxy resin composition excellent in heat resistance and fracture toughness; a prepreg; and a fiber reinforced composite material having sufficient heat resistance and strength.SOLUTION: There is provided a method for producing an oxazolidone ring-containing epoxy resin (A), which comprises: a step 1 of mixing a glycidyl compound (α) represented by a specific formula (1) and a catalyst in a reactor to obtain a mixture; and a step 2 of adding an isocyanate compound (β) represented by a specific formula (2) to the mixture obtained in the step 1 over 100 to 240 minutes while controlling the temperature in the reactor in the range of 145°C to 175°C.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an epoxy resin having a specific structure, an epoxy resin obtained by a specific method, an epoxy resin composition using the same, a prepreg, and a fiber-reinforced composite material.

  Epoxy resins have excellent performance in terms of mechanical properties, electrical properties, thermal properties, chemical resistance, adhesion, etc., so that epoxy resins can be used in paints, electrical and electronic insulating materials, and adhesives. It is used for a wide range of applications. In recent years, as electronic devices have advanced functions and miniaturization, high-density mounting has progressed. As a result, the epoxy resin used has excellent heat resistance, electrical characteristics, flame resistance, and chemical resistance. It is highly desirable to have

  Patent Document 1 discloses an oxazolidone ring-containing epoxy resin as an epoxy resin having heat resistance and chemical resistance.

Japanese National Patent Publication No. 4-506678

  However, the epoxy resin described in Patent Document 1 increases the amount of isocyanate in order to obtain heat resistance, and at the same time, increases the viscosity and lowers the solvent solubility, making it difficult to achieve both heat resistance and handleability. It becomes.

  In order to solve the above problems, the present inventors have conducted extensive research on production methods, and as a result, according to the production method including a specific step, the occurrence of high molecular weight components in the reaction between isocyanate groups and epoxy groups is remarkable. Epoxy resin composition, prepreg, and sufficient heat resistance with excellent heat resistance and fracture toughness by using the epoxy resin. The present inventors have found that a fiber-reinforced composite material having high strength can be obtained.

  That is, the present invention is as follows.

[1]
Step 1 of mixing a glycidyl compound (α) represented by the following formula (1) and a catalyst in a reactor to obtain a mixture;
While controlling the temperature in the reactor in the range of 145 ° C. to 175 ° C., the isocyanate compound (β) represented by the following formula (2) is added to the mixture obtained in the step 1 over 100 minutes to 240 minutes. Step 2 to be introduced and
The manufacturing method of an oxazolidone ring containing epoxy resin (A) which has these.
(In formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents an n-valent organic group, and n represents an integer of 1 to 3)
(In formula (2), R ³ is an m-valent organic group, and m represents an integer of 1 to 5.)
[2]
The manufacturing method of the oxazolidone ring containing epoxy resin (A) as described in [1] which performs the said process 1 in the range of 40 to 150 degreeC.
[3]
The isocyanate compound (β) represented by the following formula (2) is added to the mixture of the glycidyl compound (α) represented by the following formula (1) and the catalyst at 145 ° C. to 175 ° C. over 100 to 240 minutes. An oxazolidone ring-containing epoxy resin (A) obtained by
(In formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents an n-valent organic group, and n represents an integer of 1 to 3)
(In formula (2), R ³ is an m-valent organic group, and m represents an integer of 1 to 5.)
[4]
The oxazolidone ring-containing epoxy resin (A) according to [3], wherein the mixture is obtained by mixing the glycidyl compound (α) and a catalyst at 40 ° C to 150 ° C.
[5]
The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) obtained by gel permeation chromatography (GPC) measurement is 2.0 to 3.5, and the weight average molecular weight Mw is 4000 or less, [3] or The oxazolidone ring-containing epoxy resin (A) according to [4].
[6]
The oxazolidone ring-containing epoxy resin (A) according to any one of [3] to [5], which has an epoxy equivalent of 250 to 500 g / eq.
[7]
An epoxy resin composition comprising the epoxy resin (A) according to any one of [3] to [6], an epoxy resin (B) and / or a curing agent (C) different from the epoxy resin (A).
[8]
The epoxy resin composition according to [7], further containing a plasticizer (D).
[9]
The epoxy resin composition according to [7] or [8], further containing a filler (E).
[10]
A prepreg obtained by impregnating a fiber base material with the epoxy resin composition according to any one of [7] to [9] by coating and / or dipping.
[11]
A fiber-reinforced composite material obtained using the prepreg according to [10].

  According to the present inventor, the production method including a specific step can remarkably suppress the generation of a high molecular weight component in the reaction between an isocyanate group and an epoxy group, and can produce an epoxy resin having a low melt viscosity and excellent solvent solubility. Furthermore, by using the epoxy resin, it is possible to produce an epoxy resin composition excellent in heat resistance and fracture toughness, a prepreg, and a fiber-reinforced composite material having sufficient heat resistance and strength.

1 is an IR chart of epoxy resin 1 obtained in Example 1. FIG. 1 is a diagram showing a GPC chart of an epoxy resin 1 obtained in Example 1. FIG. It is a figure which shows the GPC chart of the epoxy resin 2 obtained in Example 2. FIG. It is a figure which shows the GPC chart of the epoxy resin 6 obtained by the comparative example 1. FIG. It is a figure which shows IR chart of the halfway sampling of the epoxy resin 7 obtained by the comparative example 2. FIG. It is a figure which shows the GPC chart of the epoxy resin 7 obtained by the comparative example 2. FIG.

  Hereinafter, a mode for carrying out the present invention (hereinafter abbreviated as “this embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Production Method of Epoxy Resin (A)]
The production method of the oxazolidone ring-containing epoxy resin (A) of the present embodiment (hereinafter also simply referred to as “epoxy resin (A)”) is as follows:
Step 1 in which a mixture is obtained by mixing a glycidyl compound (α) represented by the following formula (1) (hereinafter, also simply referred to as “glycidyl compound (α)”) and a catalyst in a reactor;
While controlling the temperature in the reactor in the range of 145 ° C. to 175 ° C., the mixture obtained in Step 1 was added to the isocyanate compound (β) (hereinafter simply referred to as “isocyanate compound” represented by the following formula (2). (Also referred to as (β) ”) for 2 to 100 minutes to 240 minutes,
Have
(In formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents an n-valent organic group, and n represents an integer of 1 to 3)
(In formula (2), R ³ is an m-valent organic group, and m represents an integer of 1 to 5.)

  Moreover, it is preferable that the manufacturing method of the epoxy resin (A) of this embodiment has the process of carrying out further aging (post reaction).

Moreover, the oxazolidone ring-containing epoxy resin (A) of this embodiment is
It is obtained by adding the isocyanate compound (β) to the mixture of the glycidyl compound (α) and the catalyst at 145 ° C. to 175 ° C. over 100 to 240 minutes. Furthermore, the epoxy resin (A) of this embodiment is preferably obtained by aging after the charging.

  In this embodiment, the temperature at which the glycidyl compound (α) and the catalyst are mixed is preferably 20 ° C to 150 ° C, more preferably 40 ° C to 150 ° C, and 40 ° C to 145 ° C. Is more preferable, it is more preferable that it is 60 to 120 degreeC, and it is especially preferable that it is 70 to 110 degreeC. When the temperature at which the glycidyl compound (α) and the catalyst are mixed is not more than the above upper limit value, the self-polymerization reaction of the epoxy resin by the catalyst can be suppressed, and the high molecular weight body in the resulting epoxy resin (A) tends to decrease. is there. Further, the deactivation of the catalyst can be suppressed, the self-polymerization of the isocyanate compound (β) can be suppressed in the subsequent steps, and the high molecular weight body in the resulting epoxy resin (A) tends to be reduced. On the other hand, when the temperature at which the glycidyl compound (α) and the catalyst are mixed is equal to or higher than the lower limit, the resulting epoxy resin (A) has a low viscosity, so that the catalyst is easily dissolved and dispersed.

  The time for mixing the glycidyl compound (α) and the catalyst is not particularly limited, but is preferably in the range of 5 minutes or more and more preferably in the range of 15 minutes or more from the viewpoint of dissolving the catalyst and mixing it uniformly.

  The temperature in the reactor when the isocyanate compound (β) is added to the mixture obtained in the step 1 is controlled in the range of 145 ° C. to 175 ° C., and can be controlled in the range of 150 ° C. to 170 ° C. Preferably, it is more preferably controlled in the range of 155 ° C to 165 ° C. By setting the temperature in the reactor at the time of introducing the isocyanate compound (β) to 175 ° C. or less, performance deterioration such as increase in viscosity due to condensation reaction between epoxy resins of the obtained epoxy resin (A) is suppressed, In addition, generation of an isocyanurate ring due to catalyst deactivation at a high temperature can be suppressed. On the other hand, when the temperature in the reactor at the time of adding the isocyanate compound (β) is 145 ° C. or higher, the generation of the oxazolidone ring is accelerated, and the generation of the isocyanurate ring can be suppressed. As a result, in the resulting epoxy resin (A), the formation of a high molecular weight product due to the generation of an isocyanurate ring is suppressed, and an increase in viscosity or the like is suppressed.

  When the resulting epoxy resin (A) has a large number of isocyanurate rings, the viscosity increases during storage, and the stability over a long period of time may be deteriorated.

  Further, the resulting epoxy resin (A) is gradually decomposed when a large amount of isocyanurate rings are present in the ripening reaction, and may have a high viscosity due to the production of a high molecular weight product due to a side reaction with an epoxy group or the like. Therefore, by controlling the temperature in the reactor when the isocyanate compound (β) is added to the range of 145 ° C. to 175 ° C., the resulting epoxy resin (A) suppresses the formation of high molecular weight products and the increase in viscosity. It is possible to suppress a decrease in water resistance of the cured product and deterioration during storage.

  The charging time of the isocyanate compound (β) into the mixture of the glycidyl compound (α) and the catalyst is in the range of 100 minutes to 240 minutes, preferably in the range of 110 minutes to 180 minutes, and more preferably in the range of 120 minutes to 140 minutes. The range of minutes. By setting the charging time to 100 minutes or more, the heat generation of the isocyanate compound (β) is divided, the temperature rise in the reactor is controlled, and the generation of a high molecular weight product due to side reactions and the increase in viscosity are suppressed. Can do. When the isocyanate compound (β) is added in a short time of less than 100 minutes, the isocyanate compound (β) generates a large amount of heat, making it difficult to control the temperature in the reactor to 175 ° C. or less, and a large amount of high molecular weight is produced. There is a risk of increasing the viscosity. If it is attempted to control by lowering the jacket temperature, a temperature gradient is generated between the inside of the reactor and the vicinity of the jacket, and it becomes difficult to control the temperature above 145 ° C., particularly in the vicinity of the jacket. There is a fear. The more industrially large reactors are used, the more difficult it is to control the temperature in the reactor.

  Therefore, when the time period for adding the isocyanate compound (β) to the mixture of the glycidyl compound (α) and the catalyst is in the range of 100 minutes to 240 minutes, the resulting epoxy resin (A) has a high molecular weight product and has a high viscosity. Can be suppressed.

  The temperature of the aging step is preferably 145 ° C to 180 ° C, more preferably 150 ° C to 175 ° C, and further preferably 155 ° C to 175 ° C. By setting the temperature of the aging step to 180 ° C. or lower, the reaction between epoxy groups and free hydroxyl groups in the epoxy compound is suppressed, and the increase in viscosity of the epoxy resin (A) due to the formation of a high molecular weight is suppressed. be able to. By setting the temperature of the aging step to 150 ° C. or higher, generation of a triisocyanate ring by the remaining isocyanate compound can be suppressed, and increase in the viscosity of the epoxy resin (A) can be suppressed.

  The time for the aging step is preferably 3 hours to 10 hours, more preferably 3 hours to 8 hours, and further preferably 3 hours to 6 hours.

  The epoxy resin (A) of this embodiment preferably has a nurate ratio represented by the following formula (4) of 0.2 or less from the viewpoint of resin storage stability.

Nurate ratio = absorbance A / absorbance B (4)
(Absorbance A: Absorbance at wave number 1710 cm ⁻¹ derived from isocyanurate ring, Absorbance B: Absorbance at wave number 1750 cm ⁻¹ derived from oxazolidone ring)

In the present embodiment, the absorbances A and B are measured by infrared spectrophotometry (“FT / IR-6100” (trademark), manufactured by JASCO Corporation) with a wave number of 1710 cm ⁻¹ derived from the isocyanurate ring of the epoxy resin. The absorbance A and the absorbance B at a wave number of 1750 cm ⁻¹ derived from the oxazolidone ring were measured.

  The closer the value of the nurate ratio is to 0, the smaller the nurate ring ratio is, and the more the oxazolidone ring is the epoxy resin.

  The epoxy resin (A) of the present embodiment preferably has a Mw (weight average molecular weight) measured by the following analysis in the range of 4000 or less from the viewpoints of suppression of high viscosity, retention of solvent solubility, and toughness. The range is more preferably 1000 to 4000, still more preferably 1500 to 3500, and still more preferably 2000 to 3000. An epoxy resin having an Mw (weight average molecular weight) in the above range can be obtained, for example, by a production method having the steps 1 and 2 described above. The epoxy resin (A) can suppress increase in viscosity and decrease in solvent solubility by controlling large molecules with Mw of 4000 or less. Moreover, epoxy resin (A) can give toughness to hardened | cured material by having Mw 1000 or more and having a certain large molecule | numerator.

  In addition, the epoxy resin (A) of the present embodiment preferably has a molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) obtained by the following GPC measurement of 2.0 to 3.5, and is preferably 2.0 to 3.5. 3.3 is more preferable, and 2.0 to 3.2 is even more preferable. When the molecular weight distribution (Mw / Mn) is within the above range, the epoxy resin (A) of this embodiment tends to be an epoxy resin excellent in low melt viscosity, solvent solubility, and fracture toughness. An epoxy resin having a molecular weight distribution (Mw / Mn) in the above range can be obtained, for example, by a production method having the steps 1 and 2 described above.

  Mn, Mw, and Mw / Mn of the epoxy resin are measured by dissolving the epoxy resin in tetrahydrofuran (THF) and using gel permeation chromatography (GPC: manufactured by Tosoh Corporation; product name HLC8320GPC).

  A calibration curve for calculating Mn, Mw and Mw / Mn is prepared using polystyrene (TSKstandardPOLYSTYRENE).

  The epoxy resin (A) of the present embodiment preferably has an epoxy equivalent measured in the following analysis in the range of 250 to 500 g / eq from the viewpoints of suppression of high viscosity, retention of solvent solubility, and toughness. More preferably, it is 280-450 g / eq, More preferably, it is the range of 300-420 g / eq. The epoxy resin (A) of this embodiment can suppress an increase in viscosity and a decrease in solvent solubility by controlling large molecules with an epoxy equivalent of 500 or less. Moreover, the epoxy resin (A) of this embodiment can give toughness to hardened | cured material by having an epoxy equivalent 250 or more and having a certain large molecule | numerator. An epoxy resin having an epoxy equivalent in the above range can be obtained, for example, by a production method having the above-described steps 1 and 2.

  The epoxy equivalent of the epoxy resin is measured using a potentiometric titration method (manufactured by Mitsubishi Chemical Analytech; product name GT-200) based on JIS K-7236.

  In the epoxy resin (A) of the present embodiment, the modification rate defined by the following formula is 0.2 from the viewpoint of suppression of high viscosity, retention of solvent solubility, toughness, adhesion to metal, and electrical characteristics. It is preferable that it is the range of -0.6, More preferably, it is the range of 0.25-0.45, More preferably, it is the range of 0.27-0.43. The epoxy resin (A) of the present embodiment has a modification rate of 0.6 or less, thereby suppressing generation of large molecules and suppressing a decrease in high viscosity and solvent solubility. In addition, since the epoxy resin (A) of the present embodiment has a modification rate of 0.2 or more, the number of oxazolidone rings that are rigid and have high molecular interaction increases, so the heat resistance of the cured product is improved, Since there are many nitrogen atoms having a large interaction, the adhesiveness is improved, and the number of free hydroxyl groups generated during curing is reduced, so that the electrical characteristics tend to be improved.

Modification rate = (isocyanate group mol) / (epoxy group mol)

<Glycidyl compound (α)>
The glycidyl compound (α) used in the present embodiment is represented by the following formula (1).

In the above formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² is an n-valent organic group, n represents an integer of 1-3.

The structure of R ^{2 in} the above formula (1) preferably has a rigid skeleton or a skeleton in which molecules easily interact with each other. When R ² has such a structure, the epoxy resin (A) of the present embodiment tends to obtain a cured product having higher heat resistance (high Tg).

Here, the “skeleton in which molecules easily interact” is not particularly limited, but for example, an aromatic skeleton having a π-π interaction such as benzene, naphthalene, anthracene, biphenyl; amide, urea, urethane, sulfonyl group, etc. And a highly polar skeleton. When R ² has an aromatic skeleton, the epoxy resin (A) of the present embodiment tends to have more excellent heat resistance of the cured product.

  Here, the rigid structure means that each atom is difficult to move when the relative position of each element constituting the structural unit is changed. Examples of the rigid structure include structures having a high content ratio of a cyclic structure such as a benzene ring structure, a spiro ring structure, a nurate ring, and a cycloaliphatic structure.

R ^{2 in the} above formula (1) preferably has a chain aliphatic or alicyclic (cycloaliphatic) skeleton, and among these, an alicyclic is more preferable. When R ² has an alicyclic skeleton, the epoxy resin (A) of the present embodiment tends to have better moisture resistance of the obtained cured product.

N represents an integer of 1 to 3, and the number of n is the valence of R ² . n is appropriately selected depending on the use depending on R ² , but is preferably 2 or more. When the number of n is 2 or more, the resulting cured product tends to have more excellent heat resistance.

  N is preferably 2 or 3. When n is within the above range, the toughness (hardness of cracking of the cured product) of the obtained cured product tends to be superior.

  Although it does not specifically limit as a glycidyl compound ((alpha)), For example, any of a monoepoxy compound and a polyhydric epoxy compound, those mixtures, etc. are mentioned.

  Although it does not specifically limit as a monoepoxy compound, For example, butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, p-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxylyl glycidyl ether, glycidyl Examples include acetate, glycidyl butyrate, glycidyl hexoate, and glycidyl benzoate.

  Although it does not specifically limit as a polyhydric epoxy compound, For example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol AD, tetramethyl bisphenol S, tetrabromo bisphenol A Bisphenol type epoxy resin obtained by glycidylation of bisphenols such as tetrachlorobisphenol A and tetrafluorobisphenol A; glycidyl other dihydric phenols such as biphenol, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene 1,1,1-tris (4-hydroxyphenyl) methane, 4,4- (1- (4- (1- (4-hydroxyphenyl) -1- Epoxy resin obtained by glycidylation of trisphenols such as tilethyl) phenyl) ethylidene) bisphenol; epoxy resin obtained by glycidylation of tetrakisphenols such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane; phenol novolac , Cresol novolaks, bisphenol A novolaks, brominated phenol novolaks, novolak type epoxy resins obtained by glycidylating novolaks such as brominated bisphenol A novolaks, etc .; Aliphatic ether type epoxy resin obtained by glycidylation of monohydric alcohol; ether ester type epoxy resin obtained by glycidylation of hydroxycarboxylic acid such as p-oxybenzoic acid and β-oxynaphthoic acid Xy resin; ester type epoxy resin obtained by glycidylation of polycarboxylic acid such as phthalic acid or terephthalic acid; amine type such as glycidated product of amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol, and triglycidyl isocyanurate Examples thereof include glycidyl type epoxy resins such as epoxy resins and alicyclic epoxy compounds such as 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate.

<Isocyanate compound (β)>
The isocyanate compound (β) used in the present embodiment is represented by the following formula (2).

The isocyanate compound (β) represented by the above formula (2) has an m-valent organic group R ³ . The isocyanate compound (β) represented by the above formula (2) preferably has a skeleton in which R ³ is more rigid or a skeleton in which molecules are likely to interact with each other. When R ³ has such a structure, the epoxy resin (A) of this embodiment tends to obtain a cured product having higher heat resistance (high Tg).

Here, the “skeleton in which molecules easily interact” is not particularly limited, but for example, an aromatic skeleton having a π-π interaction such as benzene, naphthalene, anthracene, biphenyl; amide, urea, urethane, sulfonyl group, etc. And a highly polar skeleton. When R ³ has an aromatic skeleton, the epoxy resin (A) of the present embodiment tends to have more excellent heat resistance of the cured product.

  Here, the rigid structure means that each atom is difficult to move when the relative position of each element constituting the structural unit is changed. Examples of the rigid structure include structures having a high content ratio of a cyclic structure such as a benzene ring structure, a spiro ring structure, a nurate ring, and a cycloaliphatic structure.

On the other hand, the more the structure of the organic group R ³ of the isocyanate compound (β) represented by the above formula (2) has a flexible skeleton in which a molecule such as a linear aliphatic can freely rotate, the resulting oxazolidone ring is contained. The cured product of the epoxy resin (A) tends to have a high elasticity and a low toughness.

  Moreover, the larger the m of the isocyanate compound (β) represented by the above formula (2), the greater the number of oxazolidone ring skeletons in the molecule of the resulting oxazolidone ring-containing epoxy resin (A), and the Tg of the cured product. Tends to increase, and the adhesive strength to metal tends to improve. m is preferably an integer of 1 to 5, more preferably an integer of 2 to 5, and still more preferably an integer of 2 to 3. When m is 2 or more, the obtained cured product tends to have more excellent heat resistance, and when m is 5 or less, more preferably 3 or less, the resulting epoxy resin (A) It tends to be possible to suppress the increase in viscosity and the increase in softening point.

  Examples of the isocyanate compound (β) are not particularly limited. For example, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1 , 6-hexamethylene diisocyanate, lysine diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, isocyanurate modification Polyisocyanate, biuret modified polyisocyanate, urethane-modified polyisocyanates or diisocyanates, triisocyanates, and the like.

[catalyst]
The catalyst used in the present embodiment is not particularly limited as long as it is used for oxazolidone ring formation. For example, in the reaction of a glycidyl compound (α) and an isocyanate compound (β), an oxazolidone ring is selectively used. It is preferable that the catalyst is formed in the following manner.

  Specific examples of the catalyst for generating such an oxazolidone ring include, for example, lithium compounds such as lithium chloride and butoxylithium, complex salts such as boron fluoride, tetramethylammonium chloride, tetramethylammonium bromide, and tetramethylammonium iodide. Quaternary ammonium salts such as tetrabutylammonium bromide; tertiary amines such as dimethylaminoethanol, triethylamine, tributylamine, benzyldimethylamine, N-methylmorpholine; phosphines such as triphenylphosphine, allyltriphenylphosphonium bromide, diallyl Diphenylphosphonium bromide, ethyltriphenylphosphonium chloride, ethyltriphenylphosphonium iodide, tetrabutylphosphonium acetate Phosphonium compounds such as triacetic acid complexes, tetrabutylphosphonium acetate, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium iodide; combinations of triphenylantimony and iodine; imidazoles such as 2-phenylimidazole and 2-methylimidazole And the like. In addition, it is not specifically limited to these. Moreover, these catalysts can be used individually by 1 type or in combination of 2 or more types. The amount of the oxazolidone ring-forming catalyst is not particularly limited, and is preferably in the range of about 5 ppm to 2% by mass with respect to the total amount of the glycidyl compound (α) and the isocyanate compound (β) that are usually raw materials. Used, more preferably in the range of 10 ppm to 1% by weight, more preferably 20 to 5000 ppm, and still more preferably 20 to 1000 ppm. By making the amount of use of the catalyst 2% by mass or less, it becomes possible to suppress a decrease in moisture resistance of the epoxy resin (A), while on the other hand, by making the amount of use of the catalyst 5 ppm or more, the epoxy resin It becomes possible to improve the production efficiency of (A).

[Epoxy resin composition]
The epoxy resin composition of this embodiment contains the epoxy resin (A), another epoxy resin (B) different from the epoxy resin (A), and / or a curing agent (C).

[Epoxy resin (B)]
The epoxy resin (B) is not particularly limited as long as it is different from the epoxy resin (A), and various known ones can be appropriately selected and used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hindered-in type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol Novolak type epoxy resin, naphthol novolak type epoxy resin, bis A novolak type epoxy resin, dicyclopentadiene / phenol epoxy resin, alicyclic amine epoxy resin, aliphatic amine epoxy resin, and epoxy resins halogenated from these Can be mentioned. These can be used alone or in combination of two or more.

  An epoxy resin (B) is 5 mass parts-90 masses with respect to a total of 100 mass parts of an epoxy resin (A) and an epoxy resin (B) from a viewpoint of workability improvement, provision of a flame retardance, and a heat resistant improvement. Parts, preferably 10 parts by weight to 70 parts by weight.

[Curing agent (C)]
The curing agent (C) is not particularly limited, and various known materials can be appropriately selected and used. From the viewpoint of the reaction rate at the time of curing, a guanidine derivative, an aromatic amine compound, and a novolak type. It is preferably at least one selected from the group consisting of phenol resins. These guanidine derivatives, aromatic amine compounds and novolac type phenol resins can be used alone or in combination of two or more.

  Specific examples of guanidine derivatives include dicyandiamide derivatives such as dicyandiamide, dicyandiamide-aniline adduct, dicyandiamide-methylaniline adduct, dicyandiamide-diaminodiphenylmethane adduct, dicyandiamide-diaminodiphenyl ether adduct, guanidine nitrate, guanidine carbonate, phosphorus Guanidine salts such as guanidine acid, guanidine sulfamate, aminoguanidine bicarbonate, acetylguanidine, diacetylguanidine, propionylguanidine, dipropionylguanidine, cyanoacetylguanidine, guanidine succinate, diethylcyanoacetylguanidine, dicyandiamidine, N-oxymethyl -N'-cyanoguanidine, N, N'-dicarboethoxyguanidine, etc. It is not particularly limited to these.

  Specific examples of the aromatic amine compound include, for example, metaphenylene diamine, paraphenylene diamine, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl methane, 4, 4 ′. -Diamino diphenyl ether etc. are mentioned, However, It does not specifically limit to these.

  Specific examples of the novolak type phenol resin include, but are not limited to, phenol novolak, bisphenol A novolak, cresol novolak, naphthol novolak, and the like.

  The blending amount of the curing agent (C) is not particularly limited and is appropriately set according to the desired design. When the curing agent (C) is a guanidine derivative, the total amount of the epoxy resin (A) is It is preferable that it is 1-9 mass%, and when a hardening | curing agent (C) is an aromatic amine compound, it is preferable that it is 10-50 mass% with respect to the total amount of an epoxy resin (A), and a hardening | curing agent (C When the component is a novolak type phenol resin, it is preferably 20 to 60% by mass based on the total amount of the epoxy resin (A). Setting the blending amount of the curing agent (C) within these ranges is preferable from the viewpoint of suppressing the decrease in the crosslinking density and the decrease in Tg of the cured product and ensuring the moisture resistance of the cured product.

[Plasticizer (D)]
The epoxy resin composition of the present embodiment may further contain a plasticizer (D). Although it does not specifically limit as a plasticizer (D), For example, a thermoplastic elastomer and crosslinked rubber are mentioned.

  Examples of the thermoplastic elastomer include polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and the like. The latter is preferable because the physical properties such as compression strength and interlayer shear strength of the fiber-reinforced composite material are excellent.

  Examples of the crosslinked rubber include acrylonitrile-butadiene copolymer and styrene-butadiene copolymer, and the former is preferable from the viewpoint of compatibility with the epoxy resin.

  Moreover, as a plasticizer (D), polyether sulfone is preferable from a viewpoint of an electrical property improvement.

  Content of a plasticizer (D) becomes like this. Preferably it is 1-30 mass% with respect to the whole epoxy resin composition, More preferably, it is 2-20 mass%. Setting the content of the plasticizer (D) to 30% by mass or less is preferable from the viewpoint of preventing the resin viscosity from increasing and impairing the resin into the prepreg. On the other hand, setting the content of the plasticizer (D) to 1% by mass or more is preferable from the viewpoint of maintaining the prepreg tackiness well and suppressing molding defects.

[Filler (E)]
The epoxy resin composition of the present embodiment may further contain a filler (E). The filler (E) is preferable because of rheology control, that is, thickening and thixotropy imparting effects.

  The filler (E) is not particularly limited, and examples thereof include talc, aluminum silicate, finely divided silica, calcium carbonate, mica, alumina hydrate, zinc powder, carbon black, silicon carbide, etc., and impart thixotropic properties. From the standpoint of effect, finely divided silica is preferred.

  Content of a filler (E) becomes like this. Preferably it is 1-10 mass% with respect to the whole epoxy resin composition, More preferably, it is 1-5 mass%. Setting the filler (E) content to 10% by mass or less is preferable from the viewpoint of preventing the resin viscosity from being too high and impregnating the resin into the prepreg and preventing the adhesive strength between the prepregs from decreasing. It is. On the other hand, setting the filler (E) content to 1% by mass or more is preferable from the viewpoint of suppressing the occurrence of resin fading on the surface of the molded product.

[Epoxy resin varnish]
The above epoxy resin composition is preferably used as an epoxy resin varnish uniformly dissolved or dispersed in a solvent. The solvent used here is not particularly limited as long as it can dissolve or disperse the above epoxy resin composition. For example, acetone, methyl ethyl ketone, methyl cellosolve, methyl isobutyl ketone, dimethylformamide, propylene glycol monomethyl ether , Toluene, xylene and the like, and mixed solvents thereof.

[Curing accelerator]
It is also possible to adjust the curing rate of the epoxy resin composition by further blending the epoxy resin composition with a curing accelerator. As the curing accelerator, various known ones can be used without particular limitation, and examples thereof include urea compounds, imidazoles, tertiary amines, phosphines or aminotriazoles, and the above epoxy resin. A known combination with (A) can be used.

[Prepreg]
The prepreg of the present embodiment is obtained by impregnating the above epoxy resin composition onto a fiber base material by applying and / or dipping. The prepreg of the present embodiment can also be obtained by adding organic and / or inorganic short fibers to the epoxy resin composition.

  It is preferable that the prepreg of the present embodiment can be obtained by drying in addition to the step of impregnating the fiber base material with the epoxy resin composition by the above step or the step of adding short fibers to the epoxy resin composition.

  By using the above-mentioned epoxy resin composition, a prepreg having excellent stability in which mechanical strength is increased and dimensional stability is increased is produced.

  As the fiber base material used in the present embodiment, various known materials can be appropriately selected and used. Although not particularly limited, for example, various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat, asbestos Cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloth; woven or non-woven fabric obtained from synthetic fibers such as polyvinyl alcohol fiber, polyester fiber, acrylic fiber, wholly aromatic polyamide fiber, polytetrafluoroethylene fiber; Natural fiber cloth such as cotton cloth, linen cloth, felt, etc .; carbon fiber cloth; natural cellulosic cloth such as kraft paper, cotton paper, paper-glass mixed paper, etc., among others, low specific gravity, specific strength, specific elastic modulus A carbon fiber cloth having excellent resistance is preferred.

  Moreover, these fiber base materials can be used individually by 1 type or in combination of 2 or more types.

  The thickness of the fiber substrate may be appropriately set according to the thickness of the prepreg, desired mechanical strength and dimensional stability, and is usually about 0.05 to 0.30 mm, but is particularly limited. It is not a thing.

  The proportion of the fiber base material in the prepreg is appropriately set according to the desired performance of the prepreg, and is not particularly limited, and is preferably 30 to 90% by mass with respect to the total amount of the prepreg, and 40 to 80 More preferably, it is 50 mass%, and it is further more preferable that it is 50-70 mass%. Setting the fiber substrate to 30% by mass or more is preferable from the viewpoint of obtaining a cured product that is more excellent in dimensional stability and strength. On the other hand, setting the fiber substrate to 90% by mass or less is preferable from the viewpoint of obtaining a cured product that is more excellent in adhesion. In addition, in this embodiment, when it becomes 30-90 mass% with respect to the total amount of a prepreg, it is called favorable impregnation property.

  Examples of the method for producing the prepreg of the present embodiment include a method including a step of drying the fiber base material after impregnating the above epoxy resin composition and other components as necessary. Impregnation of the epoxy resin composition into the fiber base material is performed by, for example, applying the epoxy resin composition to the base material or immersing (dipping) the fiber base material in the epoxy resin composition. it can. This impregnation treatment can be repeated a plurality of times as necessary, and the impregnation is repeatedly performed using a plurality of epoxy resin compositions having different compositions and concentrations at that time to obtain a desired resin composition and resin. It is also possible to adjust the amount.

  Furthermore, when the prepreg is dried, it is preferable to adjust the degree of heating to a semi-cured state of the epoxy resin composition, that is, a so-called B-stage state. The drying conditions of the prepreg are appropriately set according to the desired material and thickness of the prepreg, and it is usually preferable that the drying temperature is 100 to 200 ° C. and the drying time is about 1 to 30 minutes.

  In the production of the prepreg of the present embodiment, an epoxy resin composition to which a coupling agent is added can be used as needed for the purpose of improving the adhesiveness at the interface between the epoxy resin composition and the fiber substrate. As a coupling agent used here, various well-known things can be selected suitably and can be used, for example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a zirco aluminate coupling agent is mentioned. However, it is not particularly limited to these.

[Fiber-reinforced composite materials]
The fiber-reinforced composite material of the present embodiment is obtained using the above prepreg. The fiber reinforced composite material of the present embodiment is preferably a carbon fiber reinforced composite material.

  Specifically, the fiber-reinforced composite material of the present embodiment can be obtained, for example, by laminating the above-described prepreg and heating and pressing.

  The heating and pressing may be performed according to a conventional method, for example, a temperature of 80 to 300 ° C., a pressure of 0.01 to 100 MPa, and a time of 1 minute to 10 hours, more preferably a temperature of 120 to 250 ° C. and a pressure. It can be carried out under conditions of 0.1 to 10 MPa and a time of 1 minute to 5 hours. By setting the temperature, pressure, and time within the above ranges, resin decomposition does not occur, adhesion between prepregs is good, and molding accuracy is good, which is preferable.

  The present embodiment will be described in more detail with reference to the following examples, but the present embodiment is not limited to the following examples. In the examples and comparative examples, the following measuring methods and reagents were used.

(1) Method for Measuring Epoxy Equivalent The epoxy equivalent of the epoxy resin obtained in the examples is measured using potentiometric titration (Mitsubishi Chemical Analytech Co., Ltd .; product name GT-200) based on JIS K-7236. did.

(2) IR measurement IR of the obtained epoxy resin was measured using infrared spectrophotometry (measuring device: “FT / IR-6100” (trademark) manufactured by JASCO Corporation).

(3) Measuring method of molecular weight distribution (Mn, Mw, Mw / Mn) Mn, Mw, and Mw / Mn of epoxy resin are obtained by dissolving epoxy resin in THF and gel permeation chromatography (GPC: manufactured by Tosoh Corporation; product) No. HLC8320GPC).
A calibration curve was prepared using polystyrene (TSKstandardPOLYSTYRENE).

(4) Softening point The softening point was calculated | required by the ring-and-ball method (Meihosha Seisakusho make, "MEIHOSHA SOFTNING POINT TETSTER" model ASP-M2SP) based on JISK-7234.

(5) Epoxy resin melt viscosity (120 ° C)
About epoxy resin, viscosity measurement device RS600 (manufactured by Eihiro Seiki Co., Ltd.) is used, and about 0.5 g of each epoxy resin sample is placed on the disk plate, and the interval between the rotor and the plate is rotated to 0.1 mm to measure the atmosphere The viscosity at which the temperature became stable at 120 ° C. (120 ° C. melt viscosity) was measured.

(6) Solvent solubility 3 g of epoxy resin and 3 g of each solvent were weighed into a glass screw tube and dissolved using a shaker at room temperature. Those that were dissolved after 2 hours were marked with ◯, those that were dissolved after 24 hours were marked with Δ, and those that were not dissolved were marked with ×. As the solvent, methyl ethyl ketone (MEK) and acetone were used.

(7) Glass transition temperature The glass transition temperature (Tg) of the cured product of the epoxy resin composition is 20 mm long × 4 mm wide × thick using a dynamic viscoelasticity measuring device DDV-25FP (manufactured by Orientec Co., Ltd.). A test piece having a thickness of 2 mm was heated at a rate of 2 ° C./min to obtain a temperature at which tan δ was maximized.

(8) Fracture toughness (K1C)
The fracture toughness (K1C) of the cured product of the epoxy resin composition was measured in accordance with an elastoplastic fracture toughness test method (JSMES 001-1981). Specifically, a test piece of length 20 mm × width 4 mm × thickness 2 mm with a crack of about 2.5 mm in the center of the test piece was measured at an indenter moving speed of 0.5 mm / min and a fulcrum distance of 17.6 mm. Measurement was performed by a three-point bending test.

(9) Compressive strength measurement The laminate obtained by impregnating carbon fiber cloth is measured for compressive strength using Autograph AGS-H (manufactured by Shimadzu Corporation) in accordance with SACMA-SRM-2R-94. did.

(10) 90 degreeC peel strength 90 degreeC peel strength was measured based on JISC6484 using autograph AGS-H (made by Shimadzu Corporation).

[Example 1]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium bromide (trade name: tetra-n-butylammonium bromide, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 150 ° C., tolylene diisocyanate (trade name: Cosmonate T-80 (trademark), 1.18 kg (manufactured by Nippon Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is maintained at 170 ° C., the reaction solution is stirred for 5 hours and aged (post-reaction), whereby the oxazolidone ring-containing epoxy resin 1 is added to 7. 09 kg was obtained. The epoxy equivalent of the obtained epoxy resin 1 was 402 g / eq. Formation of an oxazolidone ring was confirmed from the IR chart of epoxy resin 1 (see FIG. 1). Moreover, the GPC chart of the epoxy resin 1 is shown in FIG.

  The bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Corporation, epoxy equivalent 189 g / eq) used as the glycidyl compound (α) has a structure represented by the following formula (1-1). It was.

(In formula (1-1), r represents an integer of 0 or more.)

[Example 2]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium chloride (trade name: tetrabutylammonium chloride, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 160 ° C., tolylene diisocyanate (trade name: Coronate T-80 (trademark), Japan 0.97 kg of Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is kept at 170 ° C., the reaction solution is stirred for 5 hours and aged (post-reaction), whereby the oxazolidone ring-containing epoxy resin 2 is obtained. 89 kg was obtained. The epoxy equivalent of the obtained epoxy resin 2 was 343 g / eq. A GPC chart of the resulting epoxy resin 2 is shown in FIG.

[Example 3]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium iodide (trade name: tetrabutylammonium iodide, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 150 ° C., tolylene diisocyanate (trade name: Coronate T-100 (trademark), Japan 0.75 kg of Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is kept at 170 ° C., the reaction solution is stirred for 5 hours and aged (post-reaction), whereby the oxazolidone ring-containing epoxy resin 3 is obtained. 89 kg was obtained. The epoxy equivalent of the obtained epoxy resin 3 was 292 g / eq.

[Example 4]
Into the reactor, 6.0 kg of tetramethylbiphenol type epoxy resin (trade name: YX4000, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 185 g / eq) as glycidyl compound (α) is charged and heated to 110 ° C. After dissolution, 0.004 kg of tetrabutylammonium iodide (trade name: tetrabutylammonium iodide, manufactured by Wako Pure Chemical Industries, Ltd.) was added at 110 ° C. and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 160 ° C., tolylene diisocyanate (trade name: Coronate T-80 (trademark), Japan 0.71 kg of Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction liquid is raised to 170 ° C., the reaction temperature is maintained at 170 ° C., the reaction liquid is stirred for 5 hours, and aged (post-reaction) to obtain oxazolidone ring-containing epoxy resin 4. 54 kg was obtained. The epoxy equivalent of the obtained epoxy resin 4 was 279 g / eq.

  The tetramethylbiphenol type epoxy resin (trade name: YX4000, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 185 g / eq) used as the glycidyl compound (α) has a structure represented by the following formula (1-2). Had.

(In formula (1-2), s represents an integer of 0 or more.)

[Example 5]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α), and heated and stirred. -0.004 kg of methylimidazole (trade name: 2-methylimidazole, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 150 ° C., the mixture was mixed with naphthalene diisocyanate (trade name: Desmodur 15 (trademark), Sumika Bayer). 1.00 kg of Urethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is kept at 170 ° C., the reaction solution is stirred for 5 hours, and aged (post-reaction), whereby the oxazolidone ring-containing epoxy resin 5 is 6. 89 kg was obtained. The epoxy equivalent of the obtained epoxy resin 5 was 300 g / eq.

[Comparative Example 1]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium bromide (trade name: tetra-n-butylammonium bromide, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 170 ° C, tolylene diisocyanate (trade name: Cosmonate T-80 (trademark), 1.18 kg (manufactured by Nippon Polyurethane Co., Ltd.) was added over 300 minutes. Thereafter, the reaction temperature was kept at 180 ° C., and the resulting reaction solution was stirred for 5 hours and aged (post-reaction) to obtain 6.85 kg of an oxazolidone ring-containing epoxy resin 6. The epoxy equivalent of the obtained epoxy resin 6 was 392 g / eq. A GPC chart of the resulting epoxy resin 6 is shown in FIG.

[Comparative Example 2]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium chloride (trade name: tetrabutylammonium chloride, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 130 ° C, tolylene diisocyanate (trade name: Coronate T-80 (trademark), Japan 0.97 kg of Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution was raised to 170 ° C., the reaction temperature was kept at 170 ° C., the reaction solution was stirred for 1 hour, sampled, and its IR was measured. In the IR chart, a peak of an isocyanurate ring was observed at 1709 cm ⁻¹ (see FIG. 5). Furthermore, 6.76 kg of oxazolidone ring-containing epoxy resins 7 were obtained by stirring the obtained reaction liquid at 170 ° C. for 4 hours and aging (post-reaction). The epoxy equivalent of the obtained epoxy resin 7 was 333 g / eq. A GPC chart of the resulting epoxy resin 7 is shown in FIG.

[Comparative Example 3]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α) and heated and stirred. 0.004 kg of butylammonium iodide (trade name: tetrabutylammonium iodide, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 150 ° C., tolylene diisocyanate (trade name: Coronate T-100 (trademark), Japan 0.75 kg of Polyurethane Co., Ltd.) was added over 30 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is maintained at 170 ° C., the reaction solution is stirred for 5 hours, and aged (post-reaction) to obtain oxazolidone ring-containing epoxy resin 8. 46 kg was obtained. The epoxy equivalent of the obtained epoxy resin 8 was 281 g / eq.

[Comparative Example 4]
Into the reactor, 6.0 kg of tetramethylbiphenol type epoxy resin (trade name: YX4000, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 185 g / eq) as glycidyl compound (α) is charged and heated to 110 ° C. After dissolution, 0.004 kg of tetrabutylammonium iodide (trade name: tetrabutylammonium iodide, manufactured by Wako Pure Chemical Industries, Ltd.) was added at 110 ° C. and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 185 ° C., tolylene diisocyanate (trade name: Coronate T-80 (trademark), Japan 0.71 kg of Polyurethane Co., Ltd.) was added over 150 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is kept at 170 ° C., the reaction solution is stirred for 5 hours and aged (post-reaction), thereby bringing the oxazolidone ring-containing epoxy resin 9 to 6. 32 kg was obtained. The epoxy equivalent of the obtained epoxy resin 9 was 260 g / eq.

[Comparative Example 5]
Into the reactor, 6.0 kg of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Co., Ltd., epoxy equivalent 189 g / eq) is added as a glycidyl compound (α), and heated and stirred. -0.004 kg of methylimidazole (trade name: 2-methylimidazole, manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred for 10 minutes to obtain a mixture. Thereafter, the obtained mixture was further heated and heated, and after the temperature in the reactor (internal temperature) reached 150 ° C., the mixture was mixed with naphthalene diisocyanate (trade name: Desmodur 15 (trademark), Sumika Bayer). 1.00 kg of Urethane Co., Ltd.) was added over 40 minutes. Thereafter, the temperature of the obtained reaction solution is raised to 170 ° C., the reaction temperature is kept at 170 ° C., the reaction solution is stirred for 5 hours and aged (post-reaction), thereby bringing the oxazolidone ring-containing epoxy resin 10 to 6. 65 kg was obtained. The epoxy equivalent of the obtained epoxy resin 10 was 279 g / eq.

[Application Example 1]
As the epoxy resin (A), 100 g of the above epoxy resin 1 and 50 g of methyl ethyl ketone are dissolved. To the resulting solution, 3.1 g of dicyandiamide as a curing agent and 0.1 g of 2-methylimidazole as a curing accelerator are added. A resin composition was obtained.

  A glass cloth (trade name: AS2117, manufactured by Asahi Schavel Co., Ltd.) was immersed for 5 minutes in the resulting epoxy resin composition, and the epoxy resin composition was impregnated into the glass cloth. Thereafter, the glass cloth was heated in an oven at 170 ° C. for 2 minutes to obtain a prepreg.

The obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a fiber-reinforced composite material. The glass transition temperature Tg was measured from the obtained fiber reinforced composite material.

In addition, the obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and a copper foil JTCP-70 μ (manufactured by JX Nippon Mining Co., Ltd.) was further stacked, and 40 kgf / cm ² at 180 ° C. with a hot plate press. Pressing was performed for 60 minutes to obtain a copper-clad laminate. From the obtained copper clad laminate, the copper foil was peeled off at a width of 1 cm, and the 90 ° C. peel strength was measured.

After collecting the B-stage composition powder from the prepreg base material and removing the fibers with a sieve, it is put in a mold and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a cured product. Got. K1c was measured from the obtained cured product.

  A fiber-reinforced composite material was obtained in the same manner as described above except that a carbon fiber cloth (trade name: Torayca cloth CO6343, manufactured by Toray Industries, Inc.) was used instead of the glass cloth. The compressive strength was measured from the obtained fiber reinforced composite material.

[Application Example 2]
As epoxy resin (A), 100 g of the above epoxy resin 1 is dissolved in 50 g of methyl ethyl ketone, 3.1 g of dicyandiamide as a curing agent, 0.1 g of 2-methylimidazole as a curing accelerator, and polyethersulfone as a plasticizer (Sumitomo Chemical) 2.0 g of Sumika Excel, 5003P) was added to obtain an epoxy resin composition.

  A glass cloth (trade name: AS2117, manufactured by Asahi Schavel Co., Ltd.) was immersed for 5 minutes in the resulting epoxy resin composition, and the epoxy resin composition was impregnated into the glass cloth. Thereafter, the glass cloth was heated in an oven at 170 ° C. for 2 minutes to obtain a prepreg.

The obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a fiber-reinforced composite material. The glass transition temperature Tg was measured from the obtained fiber reinforced composite material.

In addition, the obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and a copper foil JTCP-70 μ (manufactured by JX Nippon Mining Co., Ltd.) was further stacked, and 40 kgf / cm ² at 180 ° C. with a hot plate press. Pressing was performed for 60 minutes to obtain a copper-clad laminate. From the obtained copper clad laminate, the copper foil was peeled off at a width of 1 cm, and the 90 ° C. peel strength was measured.

After collecting the B-stage composition powder from the prepreg base material and removing the fibers with a sieve, it is put in a mold and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a cured product. Got. K1c was measured from the obtained cured product.

  A fiber-reinforced composite material was obtained in the same manner as described above except that a carbon fiber cloth (trade name: Torayca cloth CO6343, manufactured by Toray Industries, Inc.) was used instead of the glass cloth. The compressive strength was measured from the obtained fiber reinforced composite material.

[Application Example 3]
As the epoxy resin (A), 100 g of the above epoxy resin 1 is dissolved in 50 g of methyl ethyl ketone, 3.1 g of dicyandiamide as a curing agent, 0.1 g of 2-methylimidazole as a curing accelerator, and fine particle silica as a filler (trade name: Aerosil) 2.0 g of RY200 (manufactured by Nippon Aerosil Co., Ltd.) was added to obtain an epoxy resin composition.

  A glass cloth (trade name: AS2117, manufactured by Asahi Schavel Co., Ltd.) was immersed for 5 minutes in the resulting epoxy resin composition, and the epoxy resin composition was impregnated into the glass cloth. Thereafter, the glass cloth was heated in an oven at 170 ° C. for 2 minutes to obtain a prepreg.

The obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a fiber-reinforced composite material. The glass transition temperature Tg was measured from the obtained fiber reinforced composite material.

In addition, the obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and a copper foil JTCP-70 μ (manufactured by JX Nippon Mining Co., Ltd.) was further stacked, and 40 kgf / cm ² at 180 ° C. with a hot plate press. Pressing was performed for 60 minutes to obtain a copper-clad laminate. From the obtained copper clad laminate, the copper foil was peeled off at a width of 1 cm, and the 90 ° C. peel strength was measured.

After collecting the B-stage composition powder from the prepreg base material and removing the fibers with a sieve, it is put in a mold and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a cured product. Got. K1c was measured from the obtained cured product.

  A fiber-reinforced composite material was obtained in the same manner as described above except that a carbon fiber cloth (trade name: Torayca cloth CO6343, manufactured by Toray Industries, Inc.) was used instead of the glass cloth. The compressive strength was measured from the obtained fiber reinforced composite material.

[Application Comparative Example 1]
As epoxy resin (A), 100 g of bisphenol A type epoxy resin (trade name: AER260, manufactured by Asahi Kasei Chemicals Corporation, epoxy equivalent 189 g / eq) is dissolved in 50 g of methyl ethyl ketone, 6.7 g of dicyandiamide as a curing agent, and curing accelerator As an example, 0.1 g of 2-methylimidazole was added to obtain an epoxy resin composition.

  A glass cloth (trade name: AS2117, manufactured by Asahi Schavel Co., Ltd.) was immersed for 5 minutes in the resulting epoxy resin composition, and the epoxy resin composition was impregnated into the glass cloth. Thereafter, the glass cloth was heated in an oven at 170 ° C. for 2 minutes to obtain a prepreg.

The obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a fiber-reinforced composite material. The glass transition temperature Tg was measured from the obtained fiber reinforced composite material.

In addition, the obtained prepreg was cut into 10 cm squares, 7 sheets were stacked, and a copper foil JTCP-70 μ (manufactured by JX Nippon Mining Co., Ltd.) was further stacked, and 40 kgf / cm ² at 180 ° C. with a hot plate press. Pressing was performed for 60 minutes to obtain a copper-clad laminate. From the obtained copper clad laminate, the copper foil was peeled off at a width of 1 cm, and the 90 ° C. peel strength was measured.

After collecting the B-stage composition powder from the prepreg base material and removing the fibers with a sieve, it is put in a mold and pressed with a hot plate press at 40 kgf / cm ² and 180 ° C. for 60 minutes to obtain a cured product. Got. K1c was measured from the obtained cured product.

  A fiber-reinforced composite material was obtained in the same manner as described above except that a carbon fiber cloth (trade name: Torayca cloth CO6343, manufactured by Toray Industries, Inc.) was used instead of the glass cloth. The compressive strength was measured from the obtained fiber reinforced composite material.

Claims (11)

Step 1 of mixing a glycidyl compound (α) represented by the following formula (1) and a catalyst in a reactor to obtain a mixture;
While controlling the temperature in the reactor in the range of 145 ° C. to 175 ° C., the isocyanate compound (β) represented by the following formula (2) is added to the mixture obtained in the step 1 over 100 minutes to 240 minutes. Step 2 to be introduced and
The manufacturing method of an oxazolidone ring containing epoxy resin (A) which has these.
(In formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents an n-valent organic group, and n represents an integer of 1 to 3)
(In formula (2), R ³ is an m-valent organic group, and m represents an integer of 1 to 5.)   The manufacturing method of the oxazolidone ring containing epoxy resin (A) of Claim 1 which performs the said process 1 in the range of 40 to 150 degreeC. The isocyanate compound (β) represented by the following formula (2) is added to the mixture of the glycidyl compound (α) represented by the following formula (1) and the catalyst at 145 ° C. to 175 ° C. over 100 to 240 minutes. An oxazolidone ring-containing epoxy resin (A) obtained by
(In formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ² represents an n-valent organic group, and n represents an integer of 1 to 3)
(In formula (2), R ³ is an m-valent organic group, and m represents an integer of 1 to 5.)   The oxazolidone ring-containing epoxy resin (A) according to claim 3, wherein the mixture is obtained by mixing the glycidyl compound (α) and a catalyst at 40 ° C to 150 ° C.   The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) obtained by gel permeation chromatography (GPC) measurement is 2.0 to 3.5, and the weight average molecular weight Mw is 4000 or less. 4. The oxazolidone ring-containing epoxy resin (A) according to 4.   The oxazolidone ring-containing epoxy resin (A) according to any one of claims 3 to 5, wherein an epoxy equivalent is 250 to 500 g / eq.   An epoxy resin composition comprising the epoxy resin (A) according to any one of claims 3 to 6, an epoxy resin (B) and / or a curing agent (C) different from the epoxy resin (A).   The epoxy resin composition according to claim 7, further comprising a plasticizer (D).   The epoxy resin composition according to claim 7 or 8, further comprising a filler (E).   A prepreg obtained by impregnating a fiber base material with the epoxy resin composition according to any one of claims 7 to 9 by application and / or immersion.   A fiber-reinforced composite material obtained using the prepreg according to claim 10.