JP5390455B2 - Flame retardant epoxy resin composition and cured product thereof - Google Patents

Description

  The present invention relates to a flame retardant epoxy resin composition useful in applications requiring flame retardancy in electrical / electronic materials, composite materials, paints, etc., and an epoxy resin composition excellent in flame retardancy and cured product properties, and It relates to the cured product.

  Epoxy resins have excellent adhesiveness, electrical properties, chemical resistance, heat resistance, and moldability, and are therefore used in a wide range of applications as casting materials, laminate materials, sealing materials, and coating materials. Among these applications, circuit materials, laminates, encapsulants, enclosures, etc. used in electronic parts and electrical equipment, in particular, are indispensable for flame retardance from the viewpoint of safety such as fire prevention and delayed firing. Have been used halogenated flame retardants typified by brominated epoxy resins. However, harmful halogenated gases are generated during combustion, and the use of brominated epoxy resins has become a problem in terms of environmental safety.

  Alternative materials for halogenated flame retardants include inorganic flame retardants such as aluminum hydroxide, phosphorus-containing compounds, nitrogen-containing compounds, etc. In recent years, many flame retardant formulations of epoxy resins with phosphorus compounds have been studied in particular. Yes. For example, a prescription has been proposed in which a bisphenol A type epoxy resin and a phenol novolac type epoxy resin are blended with a novolac type phenol resin as a curing agent, and phosphoric acid esters and condensed phosphoric acid esters as flame retardants (Patent Document 1). However, the bisphenol A type epoxy resin is disadvantageous in flame retardancy because it has a methyl group in the molecular skeleton. Moreover, since the viscosity was high, there existed a fault that it was inferior to a moldability as a resin composition.

  As a method for improving the flame retardancy and moldability of these flame retardant epoxy resin compositions, resin compositions using bisphenol F type epoxy resins instead of bisphenol A type epoxy resins have been proposed. Is not fully satisfied. Patent Document 2 proposes to specify the isomer structure ratio of the raw material bisphenol F in order to improve the flame retardancy of the flame retardant bisphenol F type epoxy resin composition. In Patent Document 3, the crystallinity of the epoxy resin is increased depending on the isomerism contrast of bisphenol F, and there is a report for difficult crystallization.

JP 2006-1967 A Japanese Patent No. 3471395 Specification Republished Patent 083715

  The present invention relates to a flame retardant epoxy resin composition excellent in flame retardancy, which can reduce the blending amount of a flame retardant and a flame retardant aid and obtain excellent moldability and mechanical strength for a bisphenol F type epoxy resin. The purpose is to provide.

As a result of intensive studies on a method for improving the flame retardancy of bisphenol F-type epoxy resin, the present inventors have described the content of specific components by-produced when synthesizing bisphenol F-type epoxy resin from general-purpose bisphenol F and epichlorohydrin. It has been found that an epoxy resin composition comprising a bisphenol F type epoxy resin, a curing agent and a flame retardant as essential components, having excellent flame retardancy and good molded product characteristics.
That is, the present invention provides a bisphenol F-type diglycidyl ether component in which the content of the cyclic monomer component represented by the chemical formula (2) contained in the bisphenol F-type epoxy resin represented by the general formula (1) is represented by the general formula (1). On the other hand, it is a flame retardant epoxy resin composition containing bisphenol F type epoxy resin (A), a curing agent and a flame retardant, which are 1.0% by mass or less as measured by high performance liquid chromatography.

ｎは０以上の整数である。

n is an integer of 0 or more.

  In the flame retardant epoxy resin composition, the bisphenol F type epoxy resin (A) represented by the general formula (1) has an epoxy equivalent of 165 to 1400 g / eq, and a weight in gel permeation chromatography measurement. Those having an average molecular weight of 10,000 or less are preferred. Moreover, this invention is a flame retardant epoxy resin hardened | cured material formed by hardening | curing said flame retardant epoxy resin composition.

  The flame-retardant resin composition comprising the bisphenol F-type epoxy resin of the present invention has excellent flame retardancy and is useful as a molding material for electrical and electronic materials that require flame retardancy. In addition, it is possible to reduce the amount of flame retardant in order to obtain the same flame retardancy as before, and to obtain a molding material excellent in chemical resistance, adhesion, and mechanical properties, which is a characteristic of cured epoxy resin. it can.

It is LC-MC spectrum of a cyclic monomer reference material (A-3). It is a GPC chart of an epoxy resin (A-1). It is a GPC chart of an epoxy resin (A-2). It is a HPLC chart of a cyclic monomer reference sample (sample solution concentration 473 ppm, peak area 1595). It is a HPLC chart of epoxy resin (A-1) (sample liquid concentration 1.01%, peak area 551). It is a HPLC chart of epoxy resin (A-2) (sample liquid concentration 1.00%, peak area 177).

  Bisphenol F, which is a raw material for bisphenol F-type epoxy resin, is obtained by polycondensation reaction of phenol and formaldehyde in the presence of an acidic catalyst. It is known that a compound having three types of bonding modes of an ortho-orthomethylene bond, an ortho-paramethylene bond, and a para-paramethylene bond is formed in a binuclear body having a structure.

  When a bisphenol F type epoxy resin is synthesized with an ortho-ortho bond component and epichlorohydrin, a compound of the chemical formula (2) is generated. When used in a flame retardant molding material, it does not contribute to the curing reaction and exhibits mechanical properties. In addition, it is easy to vaporize during combustion, and flame retardancy is significantly reduced.

  The synthesis of the bisphenol F type epoxy resin of the general formula (1) can be performed according to a known synthesis method. That is, the molar ratio of bisphenol F and epichlorohydrin is preferably in the range of 1: 1.0 to 4.0. When the molar ratio is less than 1: 1.0, the weight average molecular weight of the produced epoxy resin becomes too high, which is not suitable for a molding material.

  In the reaction of bisphenol F and epichlorohydrin, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide can be used, and these are used alone or as a mixture. These are used in the form of a solid or an aqueous solution, and an aqueous solution that is usually commercially available is preferred. The amount of alkali metal hydroxide used is preferably 0.9 to 1.3 mol per mol of epichlorohydrin.

This reaction can be carried out without a solvent, but can also be carried out in a solvent that does not react with an epoxy group. Specifically, aromatic hydrocarbons such as toluene, xylene, and benzene, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, acetone Ketones such as propanol, butanols such as propanol, glycol ethers such as diethylene glycol methyl ether, propylene glycol methyl ether and dipropylene glycol methyl ether, aliphatic ethers such as diethyl ether, dibutyl ether and ethylpropyl ether, dioxane And alicyclic ethers such as tetrahydrofuran, and the like can be used alone or in admixture of two or more. These solvents are in the range of 10 to 200 parts by weight, more preferably 50 to 100 parts by weight with respect to 100 parts by weight of bisphenol F. The amount of 200 parts by weight or more is not preferable because the progress of the reaction is delayed.

  The reaction can be carried out by dissolving bisphenol F in epichlorohydrin and, if necessary, a solvent, and dropping an aqueous solution of an alkali metal hydroxide at 70 to 100 ° C. for 30 minutes to 4 hours at normal pressure. At that time, the alkali metal hydroxide aqueous solution may be dropped in a lump, intermittently or continuously. Alternatively, bisphenol F may be dissolved in an alkali metal hydroxide aqueous solution and, if necessary, in a solvent, and then epichlorohydrin may be added dropwise. Similarly, the reaction can be performed at 70 to 100 ° C. under normal pressure for 30 minutes to 4 hours. If the reaction temperature is less than 70 ° C., the reaction is difficult to proceed and the reaction time becomes longer, which is not preferable. On the other hand, if the reaction temperature exceeds 100 ° C., epichlorohydrin flows out of the reaction system, which causes a shift in the molar ratio of bisphenol F and epichlorohydrin, which makes it difficult to obtain the target epoxy equivalent, which is not preferable.

  The produced bisphenol F type epoxy resin contains the cyclic monomer component of the chemical formula (2) produced by the side reaction of the ortho-ortho bond component of the raw material bisphenol F and epichlorohydrin, and therefore the bisphenol F type epoxy resin of the present invention. To obtain the cyclic monomer component must be removed.

  The method for removing the cyclic monomer component is not particularly specified, but it can be removed using a continuous thin film evaporator such as a disk type. The resin temperature is 150 ° C. to 260 ° C., preferably 180 ° C. to 230 ° C., and the pressure is preferably 1000 Pa to 0.1 Pa.

Moreover, as another removal method, it is also possible to remove using the solubility of a solvent. A solvent that does not react with the epoxy group is used alone or in combination of two or more. After the bisphenol F type epoxy resin is dissolved by heating, the resin solution is separated into two layers by standing at room temperature, and the upper layer liquid is removed. By distilling off the solvent, a bisphenol F-type epoxy resin from which the cyclic monomer component has been removed can be obtained. Solvents include hexane, heptane, octane, dimethylbutane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene and other hydrocarbons, methanol, ethanol, propanol, butanol and other alcohols, ethyl ether, isopropyl ether, Ethers such as butyl ether, diisoamyl ether, dioxane, methyl furan, tetrahydrofuran, etc., ketones such as acetone, methyl acetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, diethyl ketone, ethyl butyl ketone, cyclohexanone, methyl cellosolve, methyl Cellosolve acetate, ethyl cellosolve, water and the like can be used, but are not limited thereto.

  As the properties of the bisphenol F type epoxy resin thus obtained, the content of the cyclic monomer component represented by the chemical formula (2) is 1% by mass or less, more preferably 0.5% by mass or less, and an epoxy equivalent of 165 The range of ˜1400 g / eq, more preferably 250 to 1000 g / eq is preferable. When the epoxy equivalent is 1500 g / eq or more, the molecular weight increases and the moldability decreases. Moreover, in the bisphenol F type epoxy resin whose epoxy equivalent is less than 165 g / eq, the yield of the epoxy resin obtained by the operation of removing the cyclic monomer component is remarkably lowered.

  Examples of the epoxy resin curing agent used in the flame retardant resin composition of the present invention include organic acid dihydrazides such as succinic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, phthalic anhydride, succinic anhydride, and anhydrous Acidic anhydrides such as nadic acid, trimellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, acid functional group-terminated polyester resins, phenol formaldehyde resins , Cresol formaldehyde resin, bisphenol A formaldehyde resin, phenol resins such as bisphenol-terminated epoxy resin, amines such as diaminodiphenylmethane, imidazole, 2-methylimidazole, 2-dodecylimi Imidazoles such as sol, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole and 2-heptadecylimidazole, imidazolines such as 2-methylimidazoline and 2-ethyl-4-methylimidazoline, Examples include triazine salts of imidazole compounds, cyanoethyl salts, various salts such as cyanoethyl trimellitic acid, metal compounds such as zinc acetate and sodium acetate, amide compounds, organophosphorus compounds such as triphenylphosphine, and dicyandiamide. it can. These may be used alone or in combination of two or more.

  There is no designation | designated as a flame retardant which can be used by this invention composition, A well-known flame retardant can be used. Examples include phosphorus flame retardants, nitrogen flame retardants such as melamine derivatives, inorganic flame retardants, phosphazene flame retardants and silicon flame retardants, and halogen flame retardants and antimony flame retardants.

  In particular, phosphorus-based flame retardants include red phosphorus, surface-coated red phosphorus, triphenyl phosphate, trixylenyl phosphate, resorcinol bis (diphenyl phosphate), 4,4′-biphenol bis (diphenyl phosphate), tris (2, Examples include aromatic phosphate esters such as 4-dibromophenyl) phosphate, phosphate amine salts such as melamine phosphate, and melamine phosphate piperazine. In addition, examples of inorganic inorganic materials include aluminum hydroxide, magnesium hydroxide, zinc borate and the like, and organic acid metal salt flame retardants such as diphenylsulfone-disulfonic acid metal salts can also be used.

  In the flame-retardant resin composition of the present invention, a conventional epoxy resin can be used in combination within the range not impairing the effects of the present invention, if necessary. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, orthocresol novolak type epoxy resin, phosphorus compound You may use together 1 type (s) or 2 or more types, such as a modified | denatured epoxy resin, a bisphenol A novolak type epoxy resin, a bisphenol AD novolak type epoxy resin, a dicyclopentadiene type epoxy resin, and an alicyclic epoxy resin.

  The flame retardant resin composition of the present invention may contain one or more auxiliary materials as required. Examples of extender pigments include barium sulfate, talc, calcium carbonate, barium carbonate, silica, alumina, and mica. As the coloring pigment, titanium oxide, iron oxide, bengara, carbon black, phthalocyanine green, phthalocyanine blue, quinacridone red, and the like can be blended. Also, thermoplastic resins such as polycarbonate, polybutyral resin, polyamide resin, and polybutadiene resin can be blended. Although the usage-amount of these auxiliary materials is not specifically limited, The range of 1-200 mass% is preferable in a flame-retardant resin composition.

  In addition, the flame retardant resin composition of the present invention can be blended with an additive modifier such as a curing accelerator, a thixotropic agent, an antifoaming agent, various stabilizers, a spreading agent, and the like, if necessary.

  The flame retardant resin composition of the present invention can be blended by a usual method using the above materials. For example, an epoxy resin, a curing agent, flame retardancy and other materials are dissolved in a solvent, or heated and melted and applied to a fibrous base material to be used as a laminated molding material, or mixed with a planetary mixer and cast molding It can be melt-kneaded with a material or with a kneader, pulverized and classified, and used as a powder coating material.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto. Unless otherwise specified, “part” means mass part and “%” means mass%.

In the present invention, analysis methods and measurement methods are as follows.
(1) Epoxy equivalent: Measured according to JIS K 7236.
(2) Quantification of cyclic monomer component: The cyclic monomer component represented by the chemical formula (2) contained in the bisphenol F type epoxy resin was quantified by high performance liquid chromatography (HPLC) analysis.
Measuring instrument: Agilent 1100 series (manufactured by Agilent Technologies)
Separation column: Cadenza CD-C18 150 × 2 mm (manufactured by Intact)
Column chamber temperature: 40 ° C
Detector: Absorbance detector (wavelength 280 nm)
Eluent: (a) Water, (b) 1: 1 (vol: vol) mixture of acetonitrile and tetrahydrofuran Flow rate: 1 mL / min, Sample solution concentration: 1.0 mass / vol%, Sample solution injection amount: 5 μL
Analysis was performed under the gradient conditions shown in Table 1 below.

It was calculated from the ratio of the peak area of the cyclic monomer reference sample having a known concentration and the area of the cyclic monomer component in the sample resin.
(3) Weight average molecular weight: It was determined using a standard polystyrene calibration curve by gel permeation chromatography (GPC) method.
Measuring device: HLC-8220 (manufactured by Tosoh Corporation)
Separation columns: TSK-GEL 2000HXL, TSK-GEL 2000HXL, TSK-GEL 1000HXL in series (Tosoh Corp.) Column temperature: 40 ° C
Detector: RI detector Eluent: Tetrahydrofuran Flow rate: 1 mL / min
(4) Mass spectrometry: Determined using high performance liquid chromatography mass spectrometry (LC-MS).
Measuring machine: Agilent 1100 series (LC manufactured by Agilent Technologies)
JMS-LCmateMS-MP30 (MS made by JEOL Ltd.)
Ion source: ESI positive
Sample concentration: 100 mg / 10 ml
Injection volume: 1.0 μL
Column: Cadenza CD-C18 100 × 2 mm (manufactured by Intact)
Column temperature: 40 ° C
Eluent: acetonitrile / water (10 mM ammonium acetate)
Flow rate: 1.0 mL / min
Detector: DAD (λ = 280 nm) (LC)
TOF mass spectrometer (Positive mode) (MS)
(5) Flammability test: The test was conducted according to UL-94.

Synthesis example 1
A separable flask equipped with a stirrer, a nitrogen introducing tube, a resistance temperature detector, a dropping device, and a cooling condenser was charged with 110.6 parts of a 49% aqueous sodium hydroxide solution and 399 parts of water, and the atmosphere inside the system was replaced with nitrogen while stirring. Next, 200 parts of bisphenol-F (Bisphenol F manufactured by Honshu Chemical Industry Co., Ltd.) was added, and the system temperature was controlled at 50 ° C. to dissolve with stirring. Subsequently, 111.0 parts of epichlorohydrin was simultaneously charged from the dropping device. After the addition, the temperature in the system was controlled at 92 ° C. and the reaction was performed for 2 hours. After completion of the reaction, 327 parts of methyl isobutyl ketone was added, stirred for 15 minutes and allowed to stand, and the lower layer water was removed. Next, neutralization with phosphoric acid and washing with water were performed, the aqueous layer was removed, and after filtration, methyl isobutyl ketone was distilled off to obtain a bisphenol F type solid epoxy resin (A-1). The resin properties are shown in Table 1.

  In a separable flask, 260 parts of bisphenol F-type solid epoxy resin (A-1) and 160 parts of methyl isobutyl ketone were charged and dissolved while stirring at 80 ° C. Then, 400 parts of methanol was added and stirred at 60 ° C. for 30 minutes. The solution was transferred to a separatory funnel and allowed to stand at room temperature for 3 hours to separate the solution into two layers. The lower layer liquid was taken out and the solvent was distilled off to obtain a bisphenol F type solid epoxy resin (A-2). The resin properties are shown in Table 1.

  Further, 300 parts of methanol was added to 100 parts of the upper layer liquid, mixed, and allowed to stand at room temperature for 3 hours. After removing the lower layer separation liquid, the solvent was distilled off from the upper layer liquid, and then 100 parts of toluene was added to the dried product and 100 parts of the dried product in a beaker and dissolved. Next, 100 parts of n-hexane was added and mixed at room temperature for 30 minutes. This solution was stored in a low temperature bath at −5 ° C. for 3 weeks, and the produced crystallized product was taken out and dried at 80 ° C. to obtain a cyclic monomer reference material (A-3). This reference material (A-3) was subjected to LC-MS analysis. As a result, m / z was 274 (M + NH4), and it was a compound with a molecular weight of 256.

Synthesis example 2
As in Synthesis Example 1, a separable flask equipped with a stirrer, a nitrogen introducing tube, a resistance temperature detector, a dropping device, and a cooling condenser was charged with 110.6 parts of a 49% aqueous sodium hydroxide solution and 399 parts of water, and the system was stirred. The inner atmosphere was replaced with nitrogen. Next, 200 parts of bisphenol-F (Bisphenol F manufactured by Honshu Chemical Industry Co., Ltd.) was added, the system temperature was controlled at 50 ° C. and dissolved with stirring, and then 166.5 parts of epichlorohydrin was simultaneously added from the dropping device. After the addition, the temperature in the system was controlled at 92 ° C. and the reaction was performed for 2 hours. After completion of the reaction, 381 parts of methyl isobutyl ketone was added and the mixture was stirred for 15 minutes and allowed to stand to remove the lower layer water. Next, neutralization with phosphoric acid and washing with water were performed, the aqueous layer was removed, and after filtration, methyl isobutyl ketone was distilled off to obtain a bisphenol F-type solid epoxy resin (B-1). The resin properties are shown in Table 1.

  In a separable flask, 260 parts of bisphenol F-type solid epoxy resin (B-1) and 160 parts of methyl isobutyl ketone were charged and dissolved while stirring at 80 ° C. Then, 240 parts of methanol was added and stirred at 60 ° C. for 30 minutes. The solution was transferred to a separatory funnel and allowed to stand at room temperature for 3 hours to separate the solution into two layers. The lower layer solution was taken out and the solvent was distilled off to obtain a bisphenol F type solid epoxy resin (B-2). The resin properties are shown in Table 2.

実施例１

Example 1

  975 parts of the bisphenol F type solid epoxy resin (A-2) obtained in Synthesis Example 1 and 25 parts of YDF-170 (Bisphenol F type liquid epoxy resin manufactured by Tohto Kasei Co., Ltd .: epoxy equivalent 171 g / eq) are dissolved in 100 parts of methyl ethyl ketone. 30% of 2 parts 8% methyl cellosolve solution of DICY (Dicyandiamide manufactured by PTI Japan) as a curing agent and 2 parts of 2E4MZ (2-ethyl-4-methylimidazole manufactured by Shikoku Chemicals) as a curing agent A mixed solution was prepared by mixing 480 parts of a methanol solution and 480 parts of 50% methyl ethyl ketone solution as a flame retardant, PX-200 (Daihachi Chemical Co., Ltd. aromatic condensed phosphate ester: phosphorus content 9.3%). The prepared solution was impregnated in WEA116E106S136 (Nittobo Glass Cloth) and dried in a hot air circulation oven at 150 ° C. for 6 minutes to obtain a prepreg. Eight prepregs obtained were laminated and a laminated cured product was obtained by a vacuum heating press. The molding conditions were that after preheating at 130 ° C. for 15 minutes under vacuum, curing was performed at 170 ° C. and a molding pressure of 2 MPa for 70 minutes.

Example 2
978 parts of the bisphenol F-type solid epoxy resin (B-2) obtained in Synthesis Example 2 was mixed with 22 parts of the aforementioned YDF-170 and BRG-555 as a curing agent (phenol novolak resin manufactured by Showa Polymer Co., Ltd .: hydroxyl group equivalent: 103 g / eq) After 214 parts are melt-mixed at 110 ° C., 578 parts of the above-mentioned PX-200 is added as a flame retardant, melt-mixed again, and then 2 parts of 2E4MZ are mixed and degassed under reduced pressure to form a 1 mm thick mold. A cast cast cured product was prepared. The curing conditions were 100 ° C. for 2 hours and then curing at 150 ° C. for 3 hours.

Example 3
800 parts of bisphenol F type solid epoxy resin (B-2) obtained in Synthesis Example 2 and 200 parts of YDF-8170 (Bisphenol F type liquid epoxy resin manufactured by Tohto Kasei Co., Ltd .: epoxy equivalent 159 g / eq) and a flame retardant 430 parts of the above-mentioned PX-200 and 470 parts of Hijilite H-42M (aluminum hydroxide manufactured by Showa Denko KK) were melted and mixed under reduced pressure in a planetary mixer at 80 ° C., and then HN-2200R (Hitachi Chemical Industries) as a curing agent. 447 parts of methyltetrahydrophthalic anhydride (hydroxyl equivalent: 165 g / eq), 2 parts of 2E4MZ was added as an accelerator, mixed, degassed under reduced pressure, poured into a mold, and a 1 mm thick compression molded cured product was prepared. Curing conditions were 120 ° C. and 0.1 MPa for 2 hours, followed by curing at 150 ° C. for 5 hours.

Comparative Example 1
Similar to Example 1, 1 mm thick laminate using a blended solution prepared with bisphenol F type solid epoxy resin (A-1): 1000 parts, DICY: 12 parts, 2E4MZ: 2 parts, PX-200: 480 parts A cured product was created.

Comparative Example 2
As in Example 2, bisphenol F-type solid epoxy resin (B-1): 1000 parts, BRG-555: 214 parts, 2E4MZ: 2 parts, PX-200: 578 parts were melt-mixed, and 1 mm thick A mold cured product was prepared.

Comparative Example 3
As in Example 3, bisphenol F type solid epoxy resin (B-1): 816 parts, YDF-8170: 184, PX-200: 430 parts, Heidilite H-42M: 470 parts and HN-2200R: 447 parts 2E4MZ: 2 parts were mixed to produce a 1 mm thick compression molded cured product.

Table 3 shows the properties of the bisphenol F-type epoxy resins used in the examples and the flame retardancy of the blended parts and cured products, and Table 4 shows the properties of the bisphenol F-type epoxy resins used in the comparative examples and the difficulties of the blended parts and cured products. Showed flammability.

The LC-MC spectrum of the cyclic monomer reference substance (A-3) is shown in FIG. 1, and the GPC chart of the epoxy resin (A-1) and the GPC chart of the epoxy resin (A-2) are shown in FIG. It was shown in 3. In addition, FIGS. 4, 5 and 6 show the HPLC charts of the samples obtained in Synthesis Example 1. FIG. That is, FIG. 4 shows a cyclic monomer reference sample (sample solution concentration 473 ppm, peak area 1595), FIG. 5 shows an epoxy resin (A-1) (sample solution concentration 1.01%, peak area 551), and FIG. A-2) (sample solution concentration 1.00%, peak area 177). The details of each peak are as follows.
Peak A: Compound represented by Chemical Formula 2.
Peak B: Bisphenol F type epoxy resin which is a para-paramethylene bond.
Peak C: Bisphenol F type epoxy resin which is an ortho-paramethylene bond.
Peak D: Bisphenol F type epoxy resin which is an ortho-orthomethylene bond.

Claims (3)

The content of the cyclic monomer component represented by the chemical formula (2) contained in the bisphenol F type epoxy resin represented by the general formula (1) is higher than that of the bisphenol F type diglycidyl ether component represented by the general formula (1). A flame retardant epoxy resin composition comprising a bisphenol F type epoxy resin (A) and a curing agent and a flame retardant, which are 1.0% by mass or less, as an essential component by graphic measurement.

  The epoxy equivalent of the bisphenol F type epoxy resin (A) represented by the general formula (1) according to claim 1 is 165 to 1400 g / eq, and the weight average molecular weight in gel permeation chromatography is 10,000 or less. Item 2. A flame retardant epoxy resin composition according to Item 1.   A flame retardant epoxy resin cured product obtained by curing the flame retardant epoxy resin composition according to claim 1.

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