JP5478603B2 - Epoxy resin composition - Google Patents

Description

  The present invention relates to an epoxy resin composition having a low viscosity and excellent workability, and an epoxy resin cured product excellent in heat-resistant mechanical properties obtained by curing the epoxy resin composition.

  Epoxy resins are generally cured with various curing agents, resulting in cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc., adhesives, paints, laminates, moldings It is used in a wide range of fields such as materials and casting materials. Conventionally, bisphenol A type epoxy resin or bisphenol F type epoxy resin is mainly used as an epoxy resin in a liquid epoxy resin composition, but a reactive diluent may be added because the viscosity of the resin is relatively high. There were many. As reactive diluents, butyl glycidyl ether, allyl glycidyl ether, and phenyl glycidyl ether have been representatively used.

  When diluents such as conventional butyl glycidyl ether, allyl glycidyl ether, and phenyl glycidyl ether are added, there are problems such as a decrease in heat resistance and mechanical strength of the cured product when the addition amount is large. For this reason, as described in Patent Documents 1 and 2, a reactive diluent having a bifunctional or higher functional epoxy has been proposed. However, the reaction diluent described in Patent Document 1 has a low viscosity but has an alicyclic epoxy group. For this reason, it is a well-known fact that it is poor in reactivity as compared with conventional epichlorohydrin type epoxy compounds and can only be cured with an acid anhydride, and its application is limited. Further, Patent Document 2 proposes compounds having a cyclohexyl group, but the viscosity of these compounds is 240 cps to 3200 cps, which is higher than that of a conventional reactive diluent, and the function as a diluent is sufficient. Not.

Japanese Patent Laid-Open No. 7-9431 Japanese Patent No. 3415047

  Therefore, as a reactive diluent, the viscosity of the entire composition can be lowered, it has the same reactivity as epichlorohydrin type epoxy, and does not deteriorate the heat resistance and mechanical properties of the cured product. The appearance of agents is desired. Epoxy resins having a low chlorine concentration are desired for use in electrical and electronic parts, and the emergence of reactive diluents having a low chlorine content is awaited.

  In view of this situation, the present inventors have intensively studied for a reactive diluent having a sufficiently low viscosity and not lowering the heat resistance and mechanical properties of the cured product and having a low chlorine content. It was found that the epoxy compound represented by) satisfies these requirements, and the present invention was completed.

（式中、Ｇはエポキシ基、Ｒは水素又はアルキル基、ｎは２〜４の整数を表す） That is, the present invention includes an epoxy resin having a viscosity at 25 ° C. of 1000 mPa · s or more and an epoxy compound represented by the following formula (1), and the content of the epoxy compound is 100 parts by weight of the epoxy resin. The present invention relates to an epoxy resin composition characterized by being 1 part by weight or more and 90 parts by weight or less.

(In the formula, G represents an epoxy group, R represents hydrogen or an alkyl group, and n represents an integer of 2 to 4)

  The present invention also relates to an epoxy resin cured product obtained by blending and curing a curing agent in the above epoxy resin composition.

Hereinafter, the present invention will be described in detail.
The epoxy resin composition of this invention contains the epoxy resin whose viscosity in 25 degreeC is 1000 mPa * s or more, and the epoxy compound represented by the said Formula (1).

  As an epoxy compound represented by Formula (1), what epoxidized the corresponding vinyl compound with the peroxide can be used. The epoxy compound obtained by this method has a feature that the chlorine content is low because epichlorohydrin is not used in the synthesis. As a peroxide used for epoxidation, a normal peracid or an organic peroxide can be used.

  In the formula (1), G is an epoxy group, R is hydrogen or an alkyl group, n represents an integer of 2 to 4, n is preferably 2, and R is preferably hydrogen, a methyl group or an ethyl group. . As mentioned above, this epoxy compound can be advantageously obtained by epoxidation by oxidation of vinylbenzenes. At this time, when vinylbenzenes are a mixture, this epoxy compound is also a mixture, but there is no problem.

  The peracid is obtained, for example, by a reaction between carboxylic acid and hydrogen peroxide. As the carboxylic acid, formic acid, acetic acid, propionic acid, benzoic acid and the like can be used. In particular, formic acid and acetic acid are preferable from the viewpoint of oxidation efficiency. Hydrogen peroxide having a concentration of 25 to 75% can be used, but 50 to 70% is particularly preferable. As the peracid, an isolated one can be used, but an in-situ method in which epoxidation is carried out after the production of peracid in a reaction system for epoxidation can also be used. In this case, the epoxidation of the vinyl compound is performed by a method in which a vinyl compound and a carboxylic acid are charged and a hydrogen peroxide solution is dropped into the mixed solution to epoxidize the peroxide at the same time as the peroxide is generated.

  Although the usage-amount with respect to the vinyl compound of a peracid is not specifically limited, 0.1-5 mole times amount is preferable normally with respect to the vinyl group of a vinyl compound, and 1-2 mole times amount is more preferable. When the amount of the peracid used is less than 0.1 mol times, the yield of the epoxidized product is remarkably lowered and the amount of unreacted product increases. Moreover, even if it uses exceeding 5 mol times amount, the influence on the yield of an epoxidized substance is hardly recognized, but it exists in the tendency for economical efficiency to be impaired for collection | recovery of a residual peracid. Usually, it is carried out without a solvent, but if necessary, it is perfectly satisfactory to use an appropriate solvent. The reaction temperature is preferably 0 to 150 ° C, and preferably 20 to 100 ° C. Below 0 ° C., the reaction is slow, and above 150 ° C., the problem of peracid safety arises. Also, sulfuric acid or the like can be used as a peracid reaction accelerator.

In addition, as the organic peroxide, a compound represented by R ₁ OOH can be used. Here, R ₁ is preferably an alkyl group or an aralkyl group, and preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms.

  Specifically, t-butyl hydroperoxide, t-amyl hydroperoxide, t-hexyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxide , Diisopropylbenzene monohydroperoxide, diisopropylbenzene dihydroperoxide and the like, or a mixture of two or more thereof. Among these, preferable organic hydroperoxide is t-butyl hydroperoxide because the alcohol produced after the reaction has a low boiling point and is easy to separate and purify after the epoxidation reaction.

  These organic hydroperoxides are produced by hydrogen peroxide oxidation of olefins or tertiary alcohols, or oxygen oxidation of hydrocarbons having at least one of secondary hydrogen and tertiary hydrogen.

  The organic hydroperoxide may contain olefins, tertiary alcohols, hydrocarbons and alcohols by-produced from the organic hydroperoxide used as raw materials during production. For example, t-butyl hydroperoxide containing t-butanol and isobutane, cumene hydroperoxide containing cumyl alcohol and cumene, ethylbenzene hydroperoxide containing α-phenylethyl alcohol and ethylbenzene, and the like can be used. Further, it may be a high-purity organic hydroperoxide obtained by treating this with a known concentration method or purification method.

  Although the usage-amount with respect to the vinyl compound of organic hydroperoxide is not specifically limited, 0.8-5 mol times amount is preferable normally with respect to the vinyl group of a vinyl compound vinyl compound, and 1-2 mol times amount is more preferable. When the amount of the peracid used is less than 0.8 mole times, the yield of the epoxidized product is remarkably lowered and the amount of unreacted product increases. Moreover, even if it uses exceeding 5 mol times amount, the influence on the yield of an epoxidized substance is hardly recognized, but it exists in the tendency for economical efficiency to be impaired for collection | recovery of residual organic hydroperoxide.

  Examples of the catalyst used for epoxidation with organic hydroperoxide include molybdenum acetylacetonate, ammonium molybdate, molybdenum chloride, and molybdenum oxide as the molybdenum compound, but molybdenum acetylacetonate and ammonium molybdate as the catalyst having high reaction activity. Ammonium molybdate is more preferable from the viewpoints of catalyst separation, recovery and economy.

  The amount of the catalyst used varies depending on the charging ratio of the vinyl compound and the organic hydroperoxide, but is usually 0.1 to 70% by weight with respect to the organic hydroperoxide. If the amount is less than 0.1% by weight, the reaction is slowed down, so that the reaction is continued for a long time, the side reaction products increase, and the yield of the epoxy compound decreases. If it exceeds 70% by weight, side reactions increase and the selectivity tends to decrease.

  The epoxidation reaction can be carried out without a solvent, but an aromatic hydrocarbon solvent such as benzene or chlorobenzene; an aliphatic hydrocarbon solvent such as octane or decane; an inert solvent such as alcohols, esters or ethers. A known solvent can also be used.

  The temperature of the epoxidation reaction is usually 50 to 120 ° C, more preferably 80 to 110 ° C. Below 50 ° C, the reaction rate is slow and the reaction time becomes long. When it exceeds 120 ° C, the organic hydroperoxide itself decomposes, and the selectivity of the epoxidized product is increased by side reactions such as the ring-opening reaction of the epoxy group. It tends to decrease. Regarding the time for the epoxidation reaction, the optimum conditions vary depending on the concentration of the organic hydroperoxide, the reaction temperature, and the amount of the catalyst used, but it is usually 0.5 to 10 hours, preferably 2 to 5 hours. The reaction method is carried out by any known method such as a batch reaction or a multistage continuous reaction having a plurality of reaction kettles.

  Moreover, as the organic oxide, peroxycarboxyimidine acid represented by the following formula (2) can be used. Peroxycarboxyimidine acid is neutral or weakly alkaline and is produced by reacting nitriles with hydrogen peroxide. An epoxidized product is produced by reacting peroxycarboxyimidine acid with a vinyl compound. This is performed by adding hydrogen peroxide in the presence of a nitrile and a vinyl compound.

（式中、Ｒ_２はアルキル基を表す）

(Wherein R ₂ represents an alkyl group)

  As the nitrile, acetonitrile is generally used and is preferable. The amount of nitrile used is not particularly limited, but usually 0.8 to 20 mole times the vinyl group is preferred, and when the amount of nitrile used is less than 0.8 mole times the vinyl compound used , The yield of the epoxidized product tends to be extremely low. Moreover, even if it uses exceeding 20 mol times amount, the influence on the yield of an epoxidized substance is hardly recognized, but it exists in the tendency for economical efficiency to be impaired for collection | recovery of a nitrile.

  The amount of hydrogen peroxide used is not particularly limited, but is usually preferably 0.8 to 5 mole times the vinyl group, and the amount of hydrogen peroxide used is 0.8 mole times the vinyl compound used. If it is less than the amount, the yield of the epoxidized product tends to be remarkably lowered. Moreover, even if it uses exceeding 5 mol times amount, the influence on the yield of an epoxidized substance is hardly recognized, but it exists in the tendency for economical efficiency to be impaired.

  In the epoxidation reaction using peroxycarboxyimidine acid, alcohols are generally used as a solvent. Preferably, it is methanol.

  The temperature of the epoxidation reaction is usually 20 to 120 ° C, more preferably 30 to 60 ° C. If the reaction temperature is lower than 20 ° C, the reaction time is slow and the reaction time becomes longer. If the reaction temperature exceeds 120 ° C, decomposition of the organic peroxycarboxyimidine acid occurs, and selection of epoxidized products by side reactions such as ring-opening reaction of epoxy groups Tend to decrease. Regarding the time for the epoxidation reaction, the optimum condition varies depending on the concentration of peroxycarboxyimidine acid and the reaction temperature, but it is usually 0.5 to 10 hours, preferably 2 to 5 hours. The reaction method is carried out by any known method such as a batch reaction or a multistage continuous reaction having a plurality of reaction kettles.

  The epoxy resin having a viscosity at 25 ° C. of 1000 mPa · s or more used in the epoxy resin composition of the present invention is not particularly limited as long as the viscosity is 1000 mPa · s or more. For example, glycidyl ether type epoxy resins such as bisphenol A, bisphenol F, bisphenol AD, bromo-containing bisphenol A, phenol novolac, cresol novolac, polyphenol, straight chain aliphatic, butadiene, and urethane; Hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, aromatic, cycloaliphatic, aliphatic glycidyl ester type epoxy resin; bisphenol, ester, high molecular weight ether ester, ether ester, bromine, novolak System, methyl-substituted epoxy resin; heterocyclic epoxy resin; glycidyl amine type epoxy resin such as triglycidyl isocyanurate or tetraglycidyl diaminodiphenylmethane; epoxidized polybutadiene Or a linear aliphatic epoxy resin such as epoxy soybean oil; a viscosity of 1000 mPa · at 25 ° C. among epoxy resins such as cycloaliphatic epoxy resin, naphthalene novolac epoxy resin, diglycidyloxynaphthalene epoxy resin Among them, bisphenol A type, bisphenol F type, bisphenol AD type, and cresol novolac type glycidyl ether type epoxy resins are particularly preferable in view of performance and economy. Regarding the epoxy resin having a viscosity at 25 ° C. of less than 1000 mPa · s, the effect of reducing the viscosity by the epoxy compound of the formula (1) is low.

  The epoxy compound represented by the formula (1) used in the epoxy resin composition of the present invention has a function of reducing the viscosity of the epoxy resin composition. On the other hand, an epoxy resin having a viscosity at 25 ° C. of 1000 mPa · s or higher is a relatively general epoxy resin and has performance specific to the epoxy resin, but has a high viscosity. Hereinafter, an epoxy resin having a viscosity at 25 ° C. of 1000 mPa · s or more is also referred to as a high viscosity epoxy resin.

  As an addition amount of the epoxy compound represented by Formula (1), it is necessary to set it as the range of 1-90 weight part with respect to 100 weight part of said high-viscosity epoxy resins. Preferably it is 5-80 weight part, More preferably, it is 10-60 weight part. When the addition amount is less than 1 part by weight, the effect of reducing the viscosity is not sufficient, and when it exceeds 90 parts by weight, the physical properties of the original epoxy resin are reduced.

  In addition, the epoxy resin composition may be added with a flexible agent, a coupling agent, a flame retardant, a flame retardant aid, a colorant, a filler, etc. that are generally blended in the application field as necessary. An agent may be added within a range not impairing the performance of the present invention.

  A cured epoxy resin is obtained by adding a curing agent to the epoxy resin composition of the present invention and curing it.

  The curing agent used in the epoxy resin composition of the present invention may be a known curing agent as a general epoxy resin curing agent, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine. Primary amines such as diethylaminopropylamine, metaphenylenediamine, p, p′-diaminodiphenylmethane, diaminodiphenylsulfone; secondary amines such as diethanolamine, N-methylethanolamine, bishydroxyethyldiethylenetriamine; triethylamine, piperidine, Tertiary amines such as benzyldimethylamine 2- (dimethylaminomethyl) phenol; phthalic anhydride, hexahydrophthalic anhydride, dodecenyl succinic anhydride, trimellitic anhydride Acid, pyromellitic acid anhydride, include acid anhydrides such as HET acid, or these one or are formulated.

  As for the compounding ratio of the epoxy resin and the curing agent, it is preferable that the epoxy group and the functional group in the curing agent have an equivalent ratio of 0.8 to 1.5. Outside this range, unreacted epoxy groups or functional groups in the curing agent remain even after curing, and the physical properties of the cured product deteriorate. Here, the epoxy compound represented by Formula (1) is handled as an epoxy resin.

  Applications of the epoxy resin composition of the present invention include paints, injection materials, cast products, composite materials such as CFRP, molded products, laminates and insulating materials such as printed boards, sealing materials for electrical and electronic parts, adhesion Agents, laminates, FRP molded products, repair materials, flooring materials, road paving materials for civil engineering and the like.

  Next, in order to further clarify the characteristics of the present invention, examples will be described in detail. In the text, “parts” and “%” are all based on weight.

Synthesis example 1
A 3 L reactor was charged with 300 g of divinylbenzene (Nippon Steel Chemical's DVB-960 divinylbenzene content 97%, m-isomer / p-isomer = 62: 38) and 1200 g of ethyl acetate and stirred. Next, 1640 g of an ethyl acetate solution containing 30% peracetic acid was added dropwise over 3 hours. During the dropping, the reaction temperature was controlled to 30 ° C. After dropping, the mixture was further stirred at 30 ° C. for 3 hours. After cooling the reaction solution to room temperature, 1208 g of 20% NaOH aqueous solution was added and stirred for 1 hour, and then the aqueous layer was separated, and unreacted peracetic acid and generated acetic acid were removed. After evaporating ethyl acetate under reduced pressure using an evaporator, purification distillation (10 torr, 150 ° C.) was performed to obtain 151.6 g of diepoxyethylbenzene (DEpEB). The epoxy equivalent of the obtained diepoxyethylbenzene was 81 g / eq, the viscosity at 25 ° C. was 18 mPa · s, the purity was 97.1% (gas chromatography area%), m-isomer / p-isomer = 64: 36 (1H -NMR integration ratio). Hydrolyzable chlorine was not detected. DEpEB is an epoxy compound in which all Rs are H and n is 2 in the formula (1).

Synthesis example 2
Crude trivinylbenzene containing about 38% trivinylbenzene was obtained from 1,3,5-triethylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) by gas phase dehydrogenation reaction.
A 3 L reactor was charged with 300 g of crude trivinylbenzene and 1200 g of ethyl acetate and stirred. Next, 1640 g of an ethyl acetate solution containing 30% peracetic acid was added dropwise over 3 hours. During the dropping, the reaction temperature was controlled to 30 ° C. After dropping, the mixture was further stirred at 30 ° C. for 3 hours. After the reaction solution was cooled to room temperature, 1208 g of 20% NaOH aqueous solution was added and stirred for 1 hour, and then the aqueous layer was separated to remove unreacted peracetic acid and generated acetic acid. After evaporating ethyl acetate under reduced pressure using an evaporator, purification distillation (5 torr, 194 ° C.) was performed to obtain 90.6 g of triepoxyethylbenzene (TEpEB). The epoxy equivalent of the obtained triepoxyethylbenzene was 75 g / eq, melting point was white crystal of 38 ° C., and the purity was 98.2% (gas chromatography area%). Hydrolyzable chlorine was not detected. TEpEB is an epoxy compound in which all Rs are H and n is 3 in the formula (1).

Examples 1-3
10 parts by weight, 25 parts by weight and 50 parts by weight of DEpEB obtained in Synthesis Example 1 are added to 100 parts by weight of bisphenol A type epoxy resin (YD-128; manufactured by Tohto Kasei Co., Ltd.) and mixed to prepare an epoxy resin composition. I got a thing. The viscosity of the resin composition at 25 ° C. was measured with a B-type viscometer. To the epoxy resin composition, Rikacid MH-700 (manufactured by Shin Nippon Rika Co., Ltd.) was added so that the equivalent ratio was 0.9 and mixed uniformly, and then heated at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours. Cured to obtain a cured product. The Tg (TMA method), bending elastic modulus and bending strength of the cured product were measured. The flexural modulus and flexural strength were measured in accordance with JIS K6911 “General Thermosetting Plastic Testing Method”. The results are shown in Table 1.

Comparative Examples 1-3
10 parts by weight, 25 parts by weight and 50 parts by weight of phenylglycidyl ether (PGE; manufactured by Tokyo Chemical Industry Co., Ltd.) are added to 100 parts by weight of the bisphenol A type epoxy resin (YD-128), and mixed to form an epoxy resin composition. Got. To this epoxy resin composition, Ricacid MH-700 was added so as to have an equivalent ratio of 0.9 and mixed uniformly, and then heated and cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours to obtain a cured product. It was. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

Comparative Examples 4-6
10 parts by weight, 25 parts by weight and 50 parts by weight of butyl glycidyl ether (BGE; manufactured by Tokyo Chemical Industry Co., Ltd.) are added to 100 parts by weight of bisphenol A type epoxy resin (YD-128), and mixed to form an epoxy resin composition. Got. To this epoxy resin composition, Ricacid MH-700 was added so as to have an equivalent ratio of 0.9 and mixed uniformly, and then heated and cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours to obtain a cured product. It was. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

Example 4
50 parts by weight of DEpEB obtained in Synthesis Example 1 was added to 100 parts by weight of bisphenol F type epoxy resin (YD-170; manufactured by Tohto Kasei Co., Ltd.), and mixed to obtain an epoxy resin composition. After adding Ricacid MH-700 to the epoxy resin composition so that the equivalent ratio was 0.9 and mixing it uniformly, it was heat-cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours to obtain a cured product. . The Tg, bending elastic modulus, and bending strength of the cured product were measured.

Example 5
50 parts by weight of DEpEB obtained in Synthesis Example 1 was added to 100 parts by weight of phenol novolac type epoxy resin (YDPN-638; manufactured by Tohto Kasei Co., Ltd.) and mixed to obtain an epoxy resin composition. To this epoxy resin composition, Ricacid MH-700 was added so as to have an equivalent ratio of 0.9 and mixed uniformly, and then heated and cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours to obtain a cured product. It was. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

  Tables 1 and 2 show the viscosities measured at 25 ° C. with the blend compositions of the resin compositions of Examples 1 to 5 and Comparative Examples 1 to 6 and a B-type viscometer, and the measured physical properties of the cured products. In addition, the addition amount is a compounding amount of the epoxy compound with respect to 100 parts by weight of the epoxy resin.

Comparative Example 7
Ricacid MH-700 was added to bisphenol A type epoxy resin (YD-128) so that the equivalent ratio was 0.9 and mixed uniformly, and then heat-cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours. A cured product was obtained. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

Comparative Example 8
Ricacid MH-700 was added to bisphenol F-type epoxy resin (YD-170) so that the equivalent ratio was 0.9 and mixed uniformly, and then heat-cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours. A cured product was obtained. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

Comparative Example 9
To the phenol novolac type epoxy resin (YDPN-638), Ricacid MH-700 was added so as to have an equivalent ratio of 0.9 and mixed uniformly, and then heat-cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours. A cured product was obtained. The Tg, bending elastic modulus, and bending strength of the cured product were measured.

  Table 3 shows the viscosity of the epoxy resins used in Comparative Examples 7 to 9 at 25 ° C. and 50 ° C. and the measured physical properties of the cured products.

Examples 6-8
DEpEB obtained in Synthesis Example 1 and TEpEB obtained in Synthesis Example 2 were added to 100 parts by weight of a bisphenol A type epoxy resin (YD-128). And TEpEB = 25 parts by weight, DEpEB = 40 parts by weight, and TEpEB = 10 parts by weight, respectively, to obtain an epoxy resin composition. The viscosity of the resin composition at 25 ° C. and 50 ° C. was measured with a B-type viscometer. After adding Ricacid MH-700 to the epoxy resin composition so that the equivalent ratio was 0.9 and mixing it uniformly, it was heat-cured at 120 ° C. for 1 hour, then at 150 ° C. for 3 hours to obtain a cured product. . The Tg, bending elastic modulus, and bending strength of the cured product were measured. The results are shown in Table 4.

Reference Example Table 5 shows hydrolyzable chlorine concentrations of phenyl glycidyl ether, butyl glycidyl ether, DEpEB and TEpB.

The hydrolyzable chlorine content was analyzed by the following method. That is, about 1 g of a sample is put in a 100 mL Erlenmeyer flask and accurately weighed to a unit of 1 mg. 30 mL of dioxane was added and dissolved completely using an ultrasonic cleaner. After correctly adding 5 mL of 1N potassium hydroxide / ethanol solution and shaking well, boiling stones were added and a condenser tube was attached. The mixture was heated to about 180 ° C. and refluxed. The reflux time was correctly set to 30 minutes after boiling started. After cooling to room temperature, the cooling tube was washed with 5 mL of methanol, and the washing solution was added to the sample solution. The Erlenmeyer flask was removed from the condenser, and the sample solution was transferred to a 200 mL beaker. The inside of the flask was washed three times with 50 mL of 80% acetone water, and the washing solution was added to the sample solution. 5 mL of N / 400 sodium chloride solution was added correctly and a rotator was added. After adding 3 mL of acetic acid and stirring for 2 minutes, potentiometric titration was performed using the N / 100 silver nitrate solution under the following conditions. A blank test was performed by the same operation as above.
The hydrolyzable chlorine concentration was determined by the following formula.
Hydrolyzable chlorine (%) = F × (V−B) × 0.0355 / S
F; Factor V of N / 100 silver nitrate solution; Amount of N / 100 silver nitrate solution required for titration of sample B; Amount of N / 100 silver nitrate solution required for titration of blank test S; Amount of sample (g)

Industrial applicability

  The epoxy resin composition of the present invention has low viscosity and excellent workability, and the cured epoxy resin obtained by curing it has excellent heat resistance and mechanical properties.

Claims (2)

An epoxy resin having a viscosity at 25 ° C. of 1000 mPa · s or more and an epoxy compound represented by the following formula (1), wherein the content of the epoxy compound is 1 part by weight or more with respect to 100 parts by weight of the epoxy resin An epoxy resin composition characterized by being 90 parts by weight or less.

In the formula, G represents an epoxy group, R represents hydrogen or an alkyl group, and n represents an integer of 2 to 4.   A cured epoxy resin obtained by blending and curing a curing agent in the epoxy resin composition according to claim 1.