JP6697903B2 - Bisphenol F type epoxy resin and method for producing the same - Google Patents

Description

  The present invention relates to a bisphenol F type epoxy resin having low viscosity, low crystallinity and excellent handling property, and a method for producing the same.

Epoxy resins are widely used in applications such as civil engineering/construction, adhesives and paints because they are excellent in corrosion resistance, adhesion, chemical resistance and flexibility when combined with various curing agents. Conventionally, bisphenol A type liquid epoxy resins have been generally used in these fields. The bisphenol A type liquid resin has a high viscosity of 10,000 to 15,000 mm ² /s at room temperature, and in applications used under these room temperature environments, a solvent, a reactive diluent, and a non-reactive agent are used for the purpose of decreasing the viscosity. Generally, the viscosity is reduced by using a diluting agent or the like. On the other hand, in recent years, as the bisphenol F type liquid epoxy resin, those having a viscosity of 2,000 to 5,000 mm ² /s at room temperature are commercially available, and as a solventless type, a solvent, a reactive diluent, a non-reactive diluent. In the case of using bisphenol A as well, compared with the bisphenol A type liquid epoxy resin, a small amount of the diluting effect can be obtained, and the curability and the physical properties of the cured product are less deteriorated, so that the field of use and the amount of use are increasing. However, the bisphenol F type epoxy resin has a strong crystallinity, and there is a fatal defect that crystals are deposited in winter and adversely affect use.

As a method of controlling the crystallization of the bisphenol type epoxy resin, for example, a method of increasing the hydrolyzable chlorine content of the epoxy resin, increasing the α diol content, so-called low purity and decreasing the crystallinity is used. Came. However, these methods for reducing the purity have a problem that reactivity with a curing agent and characteristics of a cured product are deteriorated.
Further, as a bisphenol F type epoxy resin having a low crystallinity, a bisphenol F having a low binuclear purity, which is epoxidized, is commercially available, but none is useful in terms of the balance between viscosity and crystallinity.
On the other hand, a bisphenol F type epoxy resin in which the crystallinity having a specific molecular weight distribution is lowered by controlling the purity and orientation of the raw material bisphenol F has been proposed, but its crystallinity is not sufficiently satisfactory. It was (Patent Document 1)

International Publication No. 2007/083715

  An object of the present invention is to provide a bisphenol F type epoxy resin having low viscosity and low crystallinity without deteriorating the purity.

  The present inventors used bisphenol F having a high content of binuclear body as a raw material, and controlled the molar ratio of epihalohydrin per 1 mol of the phenolic hydroxyl group of bisphenol F and the water content in the reaction system to obtain n =0 content, polymer content, and α-diol content can be set within a certain range, whereby high purity, low viscosity, and formation of crystals at −10° C. for 1 month or more can be achieved. It was found that a bisphenol F type epoxy resin without generation can be obtained, and the present invention has been completed.

That is, in the present invention, in the bisphenol F type epoxy resin, the content of n=0 body in the following formula (1) in gel permeation chromatography measurement is 70 to 80 area %, and the content of n=1 body or more. Is 14 to 19 area %, and the α-diol content is 3 to 8 meq. /100 g and a viscosity at 25° C. of 2,000 to 5,000 mm ² /s, which is a bisphenol F type epoxy resin.

（式中、ｎは繰り返し数を示す。）

(In the formula, n represents the number of repetitions.)

  The epoxy equivalent of the bisphenol F type epoxy resin is 165 to 185 g/eq. Is preferred, and the hydrolyzable chlorine content is preferably 1,000 ppm or less. It is preferable that even if the bisphenol F type epoxy resin is stored under the condition of -10°C, crystals are not formed for one month or more.

  Further, the present invention provides bisphenol F having a binuclear body purity of 95 area% or more by gel permeation chromatography measurement, and 2.0 to 3.0 mol of epihalohydrin per 1 mol of a hydroxyl group of the bisphenol F, A method for producing a bisphenol F-type epoxy resin, which comprises reacting in the presence of an alkali metal hydroxide while maintaining the water content in the reaction system at 1.0 to 7.0% by weight.

  Even though the bisphenol F type epoxy resin of the present invention has high purity, it has a low viscosity and does not form crystals for one month or more under an environment of -10°C. Therefore, it is excellent in handleability even in the outdoor working environment in winter. Further, even when a diluent or the like is used for the purpose of lowering the viscosity, the amount of the diluent required is small, and there is little adverse effect on the reactivity with the curing agent and the physical properties of the cured product.

  The bisphenol F type epoxy resin of the present invention is obtained by subjecting a specific bisphenol F to a specific amount of epihalohydrin and glycidyl etherification under basic conditions in a specific range of water content in the system. The manufacturing method will be described later.

  In the bisphenol F type epoxy resin of the present invention, the content of n=0 body in the formula (1) is 70 to 80 area %, preferably 71 to 79 area %. The content of n=1 or more is 14 to 19 area% or more, and preferably 15 to 18 area %. If the content of n=0 is small, the viscosity may be high, and if it is large, the crystallinity may be high. Further, if the content of n=1 or more is small, the crystallinity may be high, and if the content is large, the viscosity may be high. In formula (1), n is the number of repetitions, and the average value of n (number average) is preferably in the range of 0.1 to 1. Here, the above area% is measured by gel permeation chromatography (GPC), and the measurement conditions are the conditions described in the examples.

The α-diol content is 3 to 8 meq. /100 g, preferably 3 to 6 meq. /100 g. If the α-diol content is low, the crystallinity may be high, and if it is high, the reactivity with the curing agent may be poor and the physical properties of the obtained cured product may be deteriorated.
The α-diol has the same meaning as 1,2-glycol defined in JIS K7146, and is a compound having a group represented by —CH ₂ —CH(OH)—CH ₂ —OH in the molecule, According to JP-A-8-319336 and the like, the content of the α-diol group in the epoxy resin obtained by the one-step method is usually 10 to 20 meq. In the case of a bisphenol A type epoxy resin having an epoxy equivalent of about 500, the ratio of the bisphenol A type epoxy resin to all the terminal functional groups is about 5 to 10%.

25 ° C. definitive viscosity (measured by Ubbelohde viscometer) is 2,000~5,000mm ² / s, preferably 2,100~4,900mm ² / s, 2,200~4,800mm ² / s is more preferable. If the viscosity is low, crystallization is likely to occur, and if it is high, the handling property becomes poor.

  The epoxy equivalent (g/eq.) is preferably 165 to 185, more preferably 170 to 175. If the epoxy equivalent is low, crystallization tends to occur, and if it is high, the viscosity becomes high and the handling property becomes poor.

  The hydrolyzable chlorine content is preferably 1,000 ppm (wt) or less, more preferably 500 ppm or less. If the content of hydrolyzable chlorine is large, the reactivity of the curing agent may be deteriorated and the physical properties of the cured product obtained may be deteriorated.

  Further, the bisphenol F type epoxy resin of the present invention not only has the above-mentioned characteristics, but also does not show precipitation of crystals even if it is left in a frozen state (for example, −10° C.) for one month.

Next, the manufacturing method of the present invention will be described.
First, bisphenol F used as a raw material in the production method of the present invention will be described.
Usually, bisphenol F contains a binuclear body represented by the following formula (2) and a polynuclear body component of three or more trinuclear bodies represented by the following formula (3). The bisphenol F used in the present invention has a binuclear content in a GPC measurement of 95% by area or more. It is preferably 96 area% or more, and more preferably 97 area% or more. If the content of the binuclear compound is less than 95% by area, the viscosity of the obtained epoxy resin may increase. Here, the conditions for GPC measurement follow the conditions described in the examples.

  Further, the bisphenol F binuclear used in the present invention has isomers. In the present invention, 4,4'-methylenediphenol (4,4'-form), 2,2'-methylenediphenol (2,2'-form), 2,4'-methylenediphenol (2,4') It is important to control the ratio of the three types of isomers ('-form), and the other isomers can be ignored. The ratio of these three kinds of isomers is an area ratio measured by high performance liquid chromatography, and 40% or less of 4,4'-form is preferable and 20 to 40% is more preferable. The 2,2'-form is preferably 20% or less, and the 2,4'-form is preferably 40 to 80%. In the case of using an epoxy resin, the crystallinity may become stronger if the amount of 4,4'-form is large, and it becomes difficult to reduce the viscosity if the amount is small. When the 2,2'-form exceeds 20% and reacts with epihalohydrin, a large amount of cyclized substance of 1 mol of the 2,2'-form and 1 mol of epihalohydrin is produced, which may adversely affect the physical properties of the cured product. . Here, the conditions of the high performance liquid chromatography measurement follow the conditions described in the examples.

  The bisphenol F type epoxy resin of the present invention comprises the above bisphenol F and 2.0 to 3.0 mol of epihalohydrin per 1 mol of the hydroxyl group of bisphenol F in the reaction system in the presence of an alkali metal hydroxide. It can be obtained by maintaining the internal water content at 1.0 to 7.0% by weight and converting to glycidyl ether.

  Examples of epihalohydrin that can be used include epichlorohydrin, α-methylepichlorohydrin, γ-methylepichlorohydrin, epibromohydrin, and the like, and industrially easily available epichlorohydrin is preferable. The amount of epihalohydrin used is in the range of 2.0 to 3.0 mol, preferably 2.2 to 2.8 mol, and more preferably 2.4 to 2.7 mol, based on 1 mol of the hydroxyl group of the raw material bisphenol F. Is.

  Examples of the alkali metal hydroxide that can be used include potassium hydroxide, sodium hydroxide, lithium hydroxide and the like. These alkali metal hydroxides may be used alone or in combination of two or more. These alkali metal hydroxides are used in the form of an aqueous solution of 20 to 50% by weight, more preferably in the range of 40 to 50% by weight. The amount of the alkali metal hydroxide used is 0.7 to 1.3 mol, preferably 0.8 to 1.2 mol, and more preferably 0.9 to 1, per mol of the phenolic hydroxyl group of the raw material bisphenol F. It is in the range of 1.1 mol.

  Further, in order to accelerate the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride may be added as a catalyst. In this case, the amount of the quaternary ammonium salt used is usually 0.1 to 15 g, preferably 0.2 to 10 g, relative to 1 mol of the hydroxyl group of the raw material bisphenol F.

  This reaction can be carried out without a solvent, but it can also be carried out in the presence of a solvent which does not react with epihalohydrin. Specifically, aromatic hydrocarbons such as benzene, toluene and xylene, and acetone, methyl ethyl ketone and methyl isobutyl. Ketones, ketones such as cyclohexanone, alcohols such as n-propyl alcohol, isopropanol, n-butyl alcohol, isobutyl alcohol, ethylene glycol methyl ether, diethylene glycol methyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, etc. Examples thereof include, but are not limited to, glycol ethers, aliphatic ethers such as diethyl ether, dibutyl ether, and ethyl propyl ether, and alicyclic ethers such as dioxane and tetrahydrofuran. These solvents may be used alone or in combination of two or more. The amount of these solvents used is in the range of 10 to 200 parts by weight, preferably 50 to 100 parts by weight, based on 100 parts by weight of bisphenol F. If the amount of the solvent used is too large, the progress of the reaction is delayed, which is not preferable.

  As the reaction form, for example, bisphenol F, epihalohydrin, and if necessary, a solvent is charged into a reaction vessel and dissolved, and then an alkali metal hydroxide aqueous solution is added dropwise at 50 to 100° C. under normal pressure or reduced pressure at 0. The reaction can be performed in 5 to 4 hours. At that time, the alkali metal hydroxide aqueous solution may be dropped continuously or may be dropped in portions. Alternatively, a method in which bisphenol F is dissolved in an aqueous solution of an alkali metal hydroxide and, if necessary, a solvent, and then epihalohydrin is added dropwise, similarly, reaction is carried out under normal pressure or reduced pressure at 50 to 100° C. for 0.5 to 4 hours. It can be performed. If the reaction temperature is too low, the reaction progresses slowly, and if it is too high, epihalohydrin may flow out of the system, which is not preferable.

  It is important to maintain the water content in the reaction system at 1.0 to 7.0% by weight, preferably 1.0 to 6.0% by weight, more preferably 1.0 to 5.0% by weight. % Range. Specifically, water in the alkali metal hydroxide aqueous solution and water produced by the reaction are distilled by azeotropic distillation of epihalohydrin and water at atmospheric pressure or under reduced pressure, the epihalohydrin is returned to the system, and water is removed from the system. A method of removing it may be mentioned. When the water content in the system is low, the α-diol content is 3 meq. There is a possibility that it will fall below 100 g, and when it is large, the α-diol content is 8 meq. There is a risk of exceeding /100g.

  When the content of hydrolyzable chlorine is too high after the completion of the reaction, alkali metal hydroxide can be added and the re-ring closure reaction can be carried out preferably at a temperature of 50 to 90° C. for 10 minutes to 2 hours. Examples of the alkali metal hydroxide used in this case include potassium hydroxide, sodium hydroxide and the like, which can be added in the form of a solid or an aqueous solution, and the amount used is 1 to 20 per equivalent of hydrolyzable chlorine. A molar range is preferred. After completion of the recyclization reaction, excess alkali metal hydroxide and by-product salt are removed by a method such as neutralization and washing with water, and then the solvent is distilled off under reduced pressure to obtain a purified bisphenol F type epoxy resin of the present invention. Be done.

  The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these as long as the gist thereof is not exceeded. Unless otherwise specified, parts represent parts by weight, and% represents% by weight. The analysis method and measurement method are shown below.

  Epoxy equivalent: measured according to JIS K7236 standard, the unit is g/eq. Is.

  Hydrolyzable chlorine content: measured in accordance with ASTM D-1726 standard, and the unit is ppm in terms of chlorine atom weight conversion.

  α-diol content: measured in accordance with JIS K7146 standard. Specifically, after dissolving the sample in chloroform, an excess ammonium benzyltrimethyl periodate solution was added and reacted, and then 10% sulfuric acid solution and 20% potassium iodide solution were added to generate 1/5 of the generated iodine. It was determined by potentiometric titration with a specified sodium thiosulfate solution, and the unit was diol group meq. /100 g.

Viscosity: The viscosity is measured at 25° C. with an Ubbelohde viscometer according to JIS K2283 standard, and the unit is mm ² /s.

Content of binuclear body in bisphenol F, content of n=0 body in epoxy resin, and content of n=1 body or more: determined by gel permeation chromatography (GPC) measurement, unit is area% is there. The GPC measurement conditions are shown below.
Device: GPC-8320 system (manufactured by Tosoh Corporation)
Column: TSK-GEL (manufactured by Tosoh Corporation)
G4000 _HXL + G2500 _HXL + G2000 _HXL x 2 pieces Temperature: 40°C
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min Detector: RI
Sample concentration: 0.1g/10mL

Bisphenol F isomer ratio: Determined by high performance liquid chromatography measurement, 4,4'-form, 2,4'-form, 2,2'-form isomer ratio (4,4'-form /2,4'-body/2,2'-body) was expressed in area% ratio. The high-performance liquid chromatography measurement conditions are shown below.
Device: Agilent-1100 (manufactured by Agilent Technology)
Column: Cadernza CD-C18 (4.6 mmφ x 150 mmL)
Temperature: 40°C
Eluent: acetonitrile/water=34/66 (volume ratio)
Flow rate: 1.0 mL/min Detector: UV, 280 nm

  Storage stability: Stored in a low temperature constant temperature bath controlled at -10°C for 90 days, the presence or absence of crystals or turbidity was visually judged, and the number of days when crystals or turbidity occurred was noted. In addition, when no crystal or turbidity was generated even after storage for 90 days, it was described as "90<".

  Pencil hardness of coating film: Measurement was carried out according to JIS K5600-5-4 standard. The test piece was applied on a 150×70×0.8 mm mild steel plate so that the dry film thickness was 100 μm, and cured at 25° C. for each day to give a test piece.

  Alkali resistance of coating film: It was applied to a 150×70×0.8 mm mild steel plate so that the dry film thickness was 100 μm, and cured at 25° C. for 7 days to obtain a test piece. The test plate was immersed in a 10% aqueous sodium hydroxide solution at 25° C. for 7 days, and the state of the coating film was observed to show the number of blisters. The smaller the number of blisters, the better the alkali resistance.

  The abbreviations used in Examples and Comparative Examples are as follows.

(Bisphenol F)
BPF-1: binuclear content=97.2 area %, isomer ratio (4,4′-body/2,4′-body/2,2′-body)=36.3/49.2/ 14.5
BPF-2: binuclear content=95.3 area%, isomer ratio=35.6/47.8/16.6
BPF-3: binuclear content=99.7 area %, isomer ratio=33.0/49.5/17.5
BPF-4: binuclear content=90.5 area %, isomer ratio=33.0/49.5/17.5

Example 1
In a glass separable flask equipped with a stirrer, a nitrogen inlet tube, a reflux condenser equipped with an oil/water separator, and a decompression device, 100 parts of BPF-1 and 231.3 parts of epichlorohydrin (phenolic hydroxyl group of bisphenol F 1 A molar ratio of epichlorohydrin per mole ECH/OH=2.5) and 1.6 parts of water were charged, and the mixture was heated to 60° C. under a nitrogen atmosphere and dissolved. Next, while maintaining the temperature in the reaction system at 60°C, the pressure was gradually reduced to azeotrope epichlorohydrin and water, the water in the upper layer was removed through an oil/water separator, and the epichlorohydrin in the lower layer was returned to the system. Brought to reflux. While maintaining this state, 73.5 parts of a 49% sodium hydroxide aqueous solution (molar ratio of sodium hydroxide per mol of phenolic hydroxyl group of bisphenol F: NaOH/OH=0.9) was added dropwise over 150 minutes. During this time, the temperature in the reaction system was maintained at 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and the water content in the system was 2.6 to 3.2%. After the completion of the dropping, the refluxed epichlorohydrin was removed to the outside of the system, and the degree of pressure reduction and temperature were gradually raised to collect and remove epichlorohydrin until the temperature finally reached 150° C. and 5 mmHg to obtain a crude epoxy resin. Then, the reaction system was returned to normal pressure, and 300 parts of toluene was added to dissolve the crude epoxy resin. To this resin solution, 10 parts of a 20% aqueous sodium hydroxide solution was added, and after reacting at 80° C. for 1.5 hours, 500 parts of water was added to separate and remove by-produced salt. After that, washing was performed several times with 300 parts of water, and the washing was repeated until the washing water became neutral. Toluene was removed from this solution by heating at 150° C. under a reduced pressure of 5 mmHg to obtain a bisphenol F type liquid resin (E-1). Table 1 shows the physical properties of the obtained bisphenol F type liquid resin.

Example 2
Using the same apparatus as in Example 1, the charged amounts of BPF-1: 100 parts, epichlorohydrin: 277.5 parts (ECH/OH=3.0), water: 1.9 parts, 49% caustic soda aqueous solution: 73.5 parts. (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% caustic soda aqueous solution was added dropwise over 180 minutes to carry out a reaction to maintain the water content in the system at 2.2 to 2.6%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-2). Table 1 shows the physical properties of the obtained bisphenol F type liquid resin.

Example 3
Using the same apparatus as in Example 1, the charged amounts of BPF-1: 100 parts, epichlorohydrin: 212.8 parts (ECH/OH=2.3), water: 1.5 parts, 49% caustic soda aqueous solution: 73.5. Parts (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% aqueous sodium hydroxide solution was added dropwise over 240 minutes to maintain the water content in the system at 1.3 to 1.9%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-3). Table 1 shows the physical properties of the obtained bisphenol F type liquid resin.

Example 4
With the same device as in Example 1. Charged amount of BPF-2: 100 parts, epichlorohydrin: 277.5 parts (ECH/OH=3.0), water: 1.9 parts, 49% caustic soda aqueous solution: 73.5 parts (NaOH/OH=0.9). ). The temperature in the reaction system was 60 to 65° C., the degree of reduced pressure was 100 to 140 mmHg, and a 49% caustic soda aqueous solution was added dropwise over 90 minutes to maintain the system water content at 3.5 to 4.0%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-4). Table 1 shows the physical properties of the obtained bisphenol F type liquid resin.

Example 5
Using the same apparatus as in Example 1, the charged amounts of BPF-3: 100 parts, epichlorohydrin: 277.5 parts (ECH/OH=3.0), water: 1.9 parts, 49% caustic soda aqueous solution: 73.5. Parts (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% caustic soda aqueous solution was added dropwise over 120 minutes to maintain the water content in the system at 3.3 to 3.7%. After the dropping was completed, the same operation as in Example 1 was carried out to obtain a bisphenol F type epoxy resin (E-5). Table 1 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative Example 1
Using the same apparatus as in Example 1, the charged amounts of BPF-3: 100 parts, epichlorohydrin: 555.0 parts (ECH/OH=6.0), water: 3.9 parts, 49% caustic soda aqueous solution: 73.5. Parts (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of reduced pressure was 100 to 140 mmHg, and a 49% caustic soda aqueous solution was added dropwise over 180 minutes to maintain the water content in the system at 2.2 to 2.6%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-6). Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative example 2
Using the same apparatus as in Example 1, the charged amounts were BPF-4: 100 parts, epichlorohydrin: 370.0 parts (ECH/OH=4.0), water: 2.6 parts, 49% caustic soda aqueous solution: 73.5. Parts (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% aqueous sodium hydroxide solution was added dropwise over 210 minutes to maintain the water content in the system at 2.0 to 2.5%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-7). Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative Example 3
In the same apparatus as in Example 1, the charged amount was BPF-4: 100 parts, epichlorohydrin 231.3 parts (ECH/OH=2.5), water: 2.6 parts, 49% caustic soda aqueous solution: 73.5 parts. (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% aqueous sodium hydroxide solution was added dropwise over 120 minutes to maintain the water content in the system at 3.0 to 3.5%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-8). Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative Example 4
To the same apparatus as in Example 1, 100 parts of BPF-3, 277.5 parts of epichlorohydrin (ECH/OH=3.0) and 56 parts of methanol were added, and heated to 70° C. under a nitrogen atmosphere to dissolve. did. Next, 41 parts of 99% sodium hydroxide in the form of flakes (NaOH/OH=1.0) was added portionwise over 90 minutes while maintaining the temperature in the reaction system at 70°C. Furthermore, the reaction was carried out at 70° C. for 1 hour under a reduced pressure of 100 mmHg. During this time, the distilled epichlorohydrin and water were separated, epichlorohydrin was returned to the reaction system, and water was removed from the outside of the reaction system. The water content in the reaction system was 0.1 to 0.9%. After completion of the reaction, while removing the refluxed epichlorohydrin out of the system, the degree of vacuum was gradually raised and the temperature was gradually raised to 150° C. and 5 mmHg of epichlorohydrin was finally recovered and removed to obtain a crude epoxy resin. Then, the same operation as in Example 1 was performed. A bisphenol F type liquid resin (E-9) was obtained. Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative Example 5
Using the same apparatus as in Example 1, the charged amount was BPF-1: 100 parts, epichlorohydrin: 231.3 parts (ECH/OH=2.5), water: 3.2 parts, 49% caustic soda aqueous solution: 73.5. Parts (NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of reduced pressure was 100 to 140 mmHg, and a 49% caustic soda aqueous solution was added dropwise over 40 minutes to maintain the water content in the system at 7.2 to 7.9%. After the dropping was completed, the same operation as in Example 1 was performed to obtain a bisphenol F type epoxy resin (E-10). Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Comparative Example 6
Using the same apparatus as in Example 1, the charged amounts of BPF-1: 100 parts, epichlorohydrin: 166.5 parts (ECH/OH=1.8), water: 1.9 parts, 49% caustic soda aqueous solution: 73.5. Parts ([NaOH/OH=0.9). The temperature in the reaction system was 60 to 65° C., the degree of vacuum was 100 to 140 mmHg, and a 49% aqueous sodium hydroxide solution was added dropwise over 150 minutes to maintain the water content in the system at 2.6 to 3.2%. After the reaction, the same operation was performed to obtain a bisphenol F type epoxy resin (E-11). Table 2 shows the physical properties of the obtained bisphenol F type liquid resin.

Example 6
The resin obtained in Example 5 (E-5), Epogose _{EN (C} 12 _{~ 13} alcohol glycidyl ether, Yokkaichi synthetic, Ltd.) was diluted with a viscosity at 25 ° C. to 1,000mm ² / s I calculated the amount of Epogosei EN when it became. The result was 9.5% of the total amount.
Resin (E-5): 90.5 parts, Epogosei EN: 9.5 parts, and triethylenetetramine: 13.0 parts are uniformly mixed to obtain a coating material, which is a mild steel plate with a dry film thickness of 100 μm. Thus, the test piece was cured by curing for a predetermined number of days. The pencil hardness and alkali resistance of the coating film are shown in Table 3.

Comparative Examples 7-9
Other than using the resin (E-8) obtained in Comparative Example 3, the resin (E-10) obtained in Comparative Example 5, or the resin (E-11) obtained in Comparative Example 6 as the resin, In the same manner as in Example 6, the amount of Epogosei EN at which the viscosity at 25° C. was 1,000 mm ² /s was determined and blended. 13.0 parts of triethylene tetramine was added to 100 parts of both to prepare a paint. This was coated in the same manner as in Example 6, and the results of evaluation of the pencil hardness and alkali resistance of the coating film are shown in Table 3.
In the table, the blending amount of EN is the amount of Epogosei EN with respect to 100 parts in total of the resin and Epogosei EN.

INDUSTRIAL APPLICABILITY The bisphenol F type epoxy resin of the present invention is useful for flooring materials, adhesives, paints and the like, especially for applications used in an outdoor environment.

Claims (4)

In the bisphenol F type epoxy resin, the content of n=0 body of the following formula (1) in gel permeation chromatography measurement is 70 to 80 area %, and the content of n = 1 body or more is 14 to 19 area %. And the α-diol content is 3 to 8 meq. /100 g, and the viscosity at 25° C. is 2,000 to 5,000 mm ² /s, a bisphenol F type epoxy resin.

(In the formula, n represents the number of repetitions.)   Epoxy equivalent is 165 to 185 g/eq. The bisphenol F type epoxy resin according to claim 1, having a hydrolyzable chlorine content of 1,000 ppm or less. The bisphenol F type epoxy resin according to claim 1 or 2 , wherein crystals are not formed for 31 days or more under storage conditions of -10°C.
A bisphenol F having a binuclear purity of 95 area% or more as determined by gel permeation chromatography and 2.0 to 3.0 mol of epihalohydrin per 1 mol of a hydroxyl group of the bisphenol F are mixed with an alkali metal hydroxide. A method for producing a bisphenol F type epoxy resin, which comprises reacting while maintaining the water content in the reaction system at 1.0 to 7.0 wt% in the presence.