Preparation method of bisphenol F epoxy resin

Abstract

The invention belongs to the technical field of bisphenol F epoxy resin, and particularly relates to a preparation method of bisphenol F epoxy resin. The preparation method comprises the following steps: mixing bisphenol F, epoxy chloropropane and an inorganic strong alkali aqueous solution in a protective gas atmosphere, and carrying out etherification reaction to obtain a reaction solution containing chlorohydrin ether; under the condition of negative pressure, dropwise adding an inorganic strong alkali aqueous solution into the reaction solution containing the chlorohydrin ether for ring-closure reaction to obtain bisphenol F epoxy resin; the step of dropwise adding comprises first-stage dropwise adding, second-stage dropwise adding and third-stage dropwise adding in sequence. By adopting a two-step method, a solvent or an auxiliary agent does not need to be added in a pre-reaction stage, and the dropwise adding procedure of liquid caustic soda is controlled in a main reaction stage, so that the alkali utilization rate is effectively improved, the raw material consumption is reduced, the side reaction is reduced, the quality of bisphenol F epoxy resin is improved, the product epoxy value is high, the hydrolyzable chlorine content is low, and the safe and green production level is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resins, and particularly relates to a method for preparing bisphenol F epoxy resin. Background Art

[0002] The -CH2- group in the molecular structure of bisphenol F epoxy resin has greater rotation than the CH3-C-CH3 group in the molecular structure of bisphenol A epoxy resin. The room temperature viscosity is only 1 / 4 to 1 / 7 of that of bisphenol A epoxy resin. Bisphenol F epoxy resin reduces the viscosity and rigidity of bisphenol A epoxy resin and increases flexibility and fluidity. Therefore, bisphenol F epoxy resin has better application performance.

[0003] At present, bisphenol F epoxy resin has excellent strength-to-weight ratio, high temperature resistance and corrosion resistance, and is widely used in wind turbine blades, structural parts of aircraft, satellites and spacecraft, and solid rocket engine casings. Therefore, it is of great significance to study the process development of bisphenol F epoxy resin.

[0004] The synthesis technique of traditional bisphenol F epoxy resin is to add quaternary ammonium salt as catalyst promoter or add organic solvent as promoter in the initial stage of reaction, such as adding benzyltrimethylammonium chloride, tetramethylammonium chloride or adding solvent methanol, secondary alcohol, isopropanol, isobutyl alcohol etc., by the above-mentioned catalyst promoter or promoter auxiliary alkali ring-opening reaction, thus generate chloroether alcohol.But the synthesis process of above-mentioned traditional bisphenol F epoxy resin is cumbersome, needs to use catalyst promoter or organic solvent, causes solvent usage high, energy consumption is high, needs to add equipment additionally to separate and recover solvent and catalyst promoter, can increase three waste treatment amount simultaneously, causes the production cost of bisphenol F epoxy resin to be higher. Summary of the invention

[0005] The object of the present invention is to provide a preparation method of bisphenol F epoxy resin. The method provided by the present invention does not need to add organic solvent or auxiliary agent in the reaction stage, and at the same time improves the utilization rate of alkali, reduces the consumption of raw materials, reduces side reactions, improves the quality of bisphenol F epoxy resin, realizes high epoxy value and low hydrolyzable chlorine of the product, reaches a safe and green production level, effectively reduces the production cost of bisphenol F epoxy resin, and is suitable for industrial production.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing bisphenol F epoxy resin, comprising the following steps:

[0008] In a protective gas atmosphere, bisphenol F, epichlorohydrin and a first inorganic strong base aqueous solution are mixed to carry out an etherification reaction to obtain a reaction solution containing chlorohydrin ether;

[0009] Under negative pressure, a second inorganic strong alkali aqueous solution is added dropwise to the reaction solution containing the chlorohydrin ether to carry out a ring-closing reaction to obtain a bisphenol F epoxy resin; the dropping includes sequentially performing a first stage dropping, a second stage dropping and a third stage dropping, the first stage dropping time, the second stage dropping time and the third stage dropping time respectively account for 1 / 3 of the total dropping time, the mass of the second inorganic strong alkali aqueous solution added dropwise in the first stage accounts for 25-30% of the total mass of the second inorganic strong alkali aqueous solution, the mass of the second inorganic strong alkali aqueous solution added dropwise in the second stage accounts for 30-32% of the total mass of the second inorganic strong alkali aqueous solution, and the mass of the second inorganic strong alkali aqueous solution added dropwise in the third stage accounts for 38-45% of the total mass of the second inorganic strong alkali aqueous solution; during the ring-closing reaction, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

[0010] Preferably, after the second inorganic strong alkali aqueous solution is added dropwise, a closed-loop reaction liquid is obtained; and then epichlorohydrin is removed from the closed-loop reaction liquid to obtain a crude reaction liquid of bisphenol F epoxy resin;

[0011] The bisphenol F epoxy resin crude reaction liquid and the first organic solvent are mixed to obtain a mixed solution; a third inorganic strong alkali aqueous solution is added dropwise to the mixed solution for a refining reaction to obtain a refined reaction liquid;

[0012] The refined reaction liquid and the extraction solvent are mixed and then allowed to stand for stratification to obtain an oil phase product; the extraction solvent is the second organic solvent, or the second organic solvent and water;

[0013] The oil phase product is sequentially neutralized, washed with water and desolventized to obtain a refined product of bisphenol F epoxy resin.

[0014] Preferably, the inorganic strong base in the first inorganic strong base aqueous solution comprises sodium hydroxide and / or potassium hydroxide;

[0015] The mass percentage of the inorganic strong base in the first inorganic strong base aqueous solution is 32-50%;

[0016] The molar ratio of the inorganic strong alkali in the first inorganic strong alkali aqueous solution to the bisphenol F is 0.15-0.16:1.

[0017] Preferably, the molar ratio of the bisphenol F to the epichlorohydrin is 0.5:(2.5-4);

[0018] The protective gas is nitrogen, and the flow rate of the protective gas is 15 to 20 L / h.

[0019] Preferably, the conversion rate of bisphenol F in the etherification reaction is 87-94%.

[0020] Preferably, the temperature of the etherification reaction is 50-55° C. and the time is 2 hours.

[0021] Preferably, the temperature of the ring-closing reaction is 60 to 63° C.; the negative pressure condition of the ring-closing reaction is -78 to 80 kPa.

[0022] Preferably, the inorganic strong base in the second inorganic strong base aqueous solution comprises sodium hydroxide and / or potassium hydroxide;

[0023] The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is 45-50%;

[0024] The total time for adding the second inorganic strong base aqueous solution is 3 hours;

[0025] The molar ratio of the bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is 0.5:(0.9-1).

[0026] Preferably, the first organic solvent and the second organic solvent include toluene or methyl isobutyl ketone;

[0027] The inorganic strong alkali in the third inorganic strong alkali aqueous solution includes sodium hydroxide and / or potassium hydroxide;

[0028] The mass percentage of the inorganic strong base in the third inorganic strong base aqueous solution is 30-32%;

[0029] The molar ratio of the inorganic strong base to the bisphenol F in the third inorganic strong base aqueous solution is (0.14-0.15):0.5.

[0030] Preferably, the temperature of the refining reaction is 80-90° C., the dripping time of the third inorganic strong alkali aqueous solution is 20-30 min, and the heat preservation reaction is carried out after the dripping is completed. The heat preservation reaction time of the refining reaction is 1-1.5 h.

[0031] The invention provides a preparation method of bisphenol F epoxy resin, comprising the following steps: in a protective gas atmosphere, mixing bisphenol F, epichlorohydrin and a first inorganic strong alkali aqueous solution for etherification reaction to obtain a reaction liquid containing chlorohydrin ether; under negative pressure, dripping a second inorganic strong alkali aqueous solution into the reaction liquid containing chlorohydrin ether for ring-closing reaction to obtain the bisphenol F epoxy resin; the dripping comprises sequentially performing first-stage dripping, second-stage dripping and third-stage dripping, wherein the first-stage dripping time, the second-stage dripping time and the third-stage dripping time respectively account for 1 / 3 of the total dripping time, and the first-stage dripping time is 1 / 3 of the total dripping time. The mass of the second inorganic strong alkali aqueous solution added in the first stage accounts for 25-30% of the total mass of the second inorganic strong alkali aqueous solution, the mass of the second inorganic strong alkali aqueous solution added in the second stage accounts for 30-32% of the total mass of the second inorganic strong alkali aqueous solution, and the mass of the second inorganic strong alkali aqueous solution added in the third stage accounts for 38-45% of the total mass of the second inorganic strong alkali aqueous solution; during the ring-closing reaction, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction. The raw materials for preparing bisphenol F epoxy resin of the present invention are bisphenol F, epichlorohydrin and inorganic strong alkali aqueous solution, and the raw materials for preparing bisphenol F epoxy resin of the present invention do not contain organic solvents and catalyst aids. The invention adopts a two-step preparation method. First, a base-catalyzed ring opening is performed to cause an etherification reaction (pre-reaction) to generate chloroether alcohol. The etherification reaction does not require additional additives or solvents, thereby reducing the operation and energy consumption of separating the solvent in the later stage. The reaction liquid (pre-reaction liquid) containing chlorohydrin ether obtained by the etherification reaction continues to undergo a ring-closing reaction (main reaction) under negative pressure conditions. During the main reaction, a negative pressure segmented liquid alkali (a second inorganic strong alkali aqueous solution) is added dropwise, thereby reducing side reactions during the main reaction and improving the quality of the bisphenol F epoxy resin product. Specifically, the invention controls the second inorganic strong alkali aqueous solution to reduce the side reactions during the main reaction. The dripping speed is slow at first and then fast, so as to control the water output of the closed-loop reaction process, and the water generated by the reaction is separated from the closed-loop reaction system in time, reducing the occurrence of hydrolysis side reactions; the speed of dripping liquid alkali (the second inorganic strong alkali aqueous solution) in the early stage of the closed-loop reaction is too fast, and the bisphenol F chlorohydrin body is not fully dehydrochlorinated during the reaction process, and the closed loop is not completely completed. The substance is easily hydrolyzed by trace water to generate bisphenol F chloroglycerol ether, and the continued hydrolysis of the substance will generate bisphenol F glycerol ether, resulting in aggravation of the condensation side reaction, thereby increasing the molecular weight of the bisphenol F epoxy resin, decreasing the epoxy value, and increasing the viscosity. The speed of dripping liquid alkali in the early stage of the closed-loop reaction is too slow. Under the condition that the total alkali amount and the total dripping time remain unchanged, the alkali addition speed in the later stage will inevitably accelerate, resulting in the reaction not being able to proceed smoothly, and promoting the occurrence of by-products, and the insufficient amount of alkali added in the early stage is not completely closed, resulting in a high hydrolysis chlorine in the bisphenol F epoxy resin product.In summary, the present invention adopts a two-step method, and no solvent or auxiliary agent is required in the pre-reaction stage and the main reaction stage. The dripping procedure of liquid alkali is controlled in the main reaction stage, which effectively improves the alkali utilization rate, reduces raw material consumption, reduces side reactions, improves the quality of bisphenol F epoxy resin, achieves a high epoxy value and low hydrolyzable chlorine in the product, and reaches a safe and green production level.

[0032] Further, in the present invention, after the dropwise addition is completed, a closed-loop reaction liquid is obtained; after obtaining the closed-loop reaction liquid, the method further includes: removing epichlorohydrin from the closed-loop reaction liquid to obtain a crude reaction liquid of bisphenol F epoxy resin; mixing the crude reaction liquid of bisphenol F epoxy resin with a first organic solvent and then dropping a third inorganic strong alkali aqueous solution for a refining reaction to obtain a refined reaction liquid; mixing the refined reaction liquid, the second organic solvent and water and then standing to separate to obtain an oil phase product; neutralizing, washing and desolvating the oil phase product in sequence to obtain a refined product of bisphenol F epoxy resin. The present invention removes epichlorohydrin (ECH) and then performs a refining reaction, which can make the reaction more complete, and the hydrolyzed chlorine content in the resin product is reduced again, so as to obtain a bisphenol F epoxy resin product that meets industrial quality standards.

[0033] Further, in the present invention, the inorganic strong base in the first inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; the mass percentage of the inorganic strong base in the first inorganic strong base aqueous solution is 32-50%; the molar ratio of the inorganic strong base in the first inorganic strong base aqueous solution to the bisphenol F is 0.15-0.16:1. The present invention controls the conversion rate of bisphenol F to 87-94% by optimizing the amount of inorganic strong base (the inorganic strong base in the first inorganic strong base aqueous solution, i.e., the catalyst) in the pre-reaction stage. There will be a small amount of closed-loop reaction in the pre-reaction, and the reactions in the pre-reaction and main reaction stages are difficult to be completely separated. There will also be an etherification reaction (ring-opening reaction) in the main reaction stage. The present invention controls the conversion rate of bisphenol F in the pre-reaction stage to 87-94%, reducing side reactions. When the amount of alkali in the pre-reaction stage is too small, the conversion rate of bisphenol F is low and the reaction yield is low; when the amount of alkali in the pre-reaction stage is too large, a large amount of ECH in the system will undergo hydrolysis reaction with water in the early stage of the reaction, increasing the consumption of raw materials and the generation of by-products.

[0034] Further, in the present invention, the temperature of the ring-closing reaction is 60-63° C. In the present invention, the ring-closing reaction is an endothermic reaction. When the temperature is too low, the ring-closing reaction effect is poor; when the temperature is too high, side reactions increase, such as hydrolysis reaction of epoxy groups, branching reaction, abnormal addition reaction of phenolic hydroxyl groups with epoxy groups, molecular chain growth side reaction, etc., which ultimately lead to a large average molecular weight, high epoxy equivalent, and high viscosity of the bisphenol F epoxy resin product.

[0035] Further, in the present invention, the mass percentage of the inorganic strong base in the first inorganic strong base aqueous solution is preferably 32-50%. The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is preferably 45-50%. The present invention controls the water content in the ring-opening reaction and ring-closing reaction system by controlling the mass concentration of the inorganic strong base aqueous solution used in the ring-opening reaction and the ring-closing reaction. Too much water in the reaction system will promote the hydrolysis reaction of epichlorohydrin under alkaline conditions to generate glycerol, which further reacts with the generated epoxy resin, thereby deteriorating the product quality.

[0036] In summary, the present invention provides a method for preparing bisphenol F epoxy resin which is efficient, easy to operate and control, and has mild conditions. Inorganic strong alkali is used in the reaction process, and no auxiliary agents such as quaternary ammonium salts are contained. The wastewater (aqueous phase obtained by static stratification of the refined reaction liquid) can be treated and then electrolyzed to achieve a circular economy, green emission reduction and low carbon. The main reaction adopts a negative pressure segmented liquid alkali process, which effectively improves the alkali utilization rate, reduces raw material consumption, reduces side reactions, and improves the product performance of the epoxy resin. The method is suitable for industrial production. DETAILED DESCRIPTION

[0037] The present invention provides a method for preparing bisphenol F epoxy resin, comprising the following steps:

[0038] In a protective gas atmosphere, bisphenol F, epichlorohydrin and a first inorganic strong base aqueous solution are mixed to carry out an etherification reaction to obtain a reaction solution containing chlorohydrin ether;

[0039] Under negative pressure, a second inorganic strong alkali aqueous solution is added dropwise to the reaction solution containing the chlorohydrin ether to carry out a ring-closing reaction to obtain a bisphenol F epoxy resin; the dropping includes sequentially performing a first stage dropping, a second stage dropping and a third stage dropping, the first stage dropping time, the second stage dropping time and the third stage dropping time respectively account for 1 / 3 of the total dropping time, the mass of the second inorganic strong alkali aqueous solution added dropwise in the first stage accounts for 25-30% of the total mass of the second inorganic strong alkali aqueous solution, the mass of the second inorganic strong alkali aqueous solution added dropwise in the second stage accounts for 30-32% of the total mass of the second inorganic strong alkali aqueous solution, and the mass of the second inorganic strong alkali aqueous solution added dropwise in the third stage accounts for 38-45% of the total mass of the second inorganic strong alkali aqueous solution; during the ring-closing reaction, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

[0040] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0041] The raw materials used in the preparation method provided by the present invention do not contain auxiliary agents and organic solvents.

[0042] In the present invention, bisphenol F, epichlorohydrin and a first inorganic strong alkali aqueous solution are mixed in a protective gas atmosphere for etherification reaction to obtain a reaction solution containing chlorohydrin ether. In the present invention, the purity of the bisphenol F is preferably ≥90%. The purity of the epichlorohydrin is preferably ≥99.9%. The inorganic strong base in the first inorganic strong alkali aqueous solution preferably includes sodium hydroxide and / or potassium hydroxide, and specifically sodium hydroxide in the embodiment. The mass percentage of the inorganic strong base in the first inorganic strong alkali aqueous solution is preferably 32-50%. The molar ratio of the inorganic strong base in the first inorganic strong alkali aqueous solution to the bisphenol F is preferably 0.15-0.16:1, and specifically preferably 0.16:1 and 0.15:1. The molar ratio of the bisphenol F to the epichlorohydrin is preferably 0.5:(2.5-4), and specifically preferably 0.5:4 and 0.5:2.5. The protective gas is preferably nitrogen, and the flow rate of the protective gas is preferably 15 to 20 L / h, and more preferably 15 L / h or 20 L / h. The temperature of the etherification reaction is preferably 50 to 55° C., and more preferably 50° C. or 55° C., and the time of the etherification reaction is preferably 2 hours. The etherification reaction generates chlorohydrin ether, and the conversion rate of bisphenol F in the etherification reaction is preferably 87 to 94%.

[0043] In the present invention, after obtaining the reaction solution containing the chlorohydrin ether, it is preferred to turn off the protective gas and perform the ring-closing reaction described below.

[0044] After obtaining a reaction liquid containing chlorohydrin ether, the present invention drips a second inorganic strong alkali aqueous solution into the reaction liquid containing chlorohydrin ether under negative pressure to carry out a ring-closing reaction to obtain a bisphenol F epoxy resin; the dripping comprises sequentially performing a first-stage dripping, a second-stage dripping and a third-stage dripping, the first-stage dripping time, the second-stage dripping time and the third-stage dripping time respectively account for 1 / 3 of the total dripping time, the mass of the second inorganic strong alkali aqueous solution dripped in the first stage accounts for 25-30% of the total mass of the second inorganic strong alkali aqueous solution, the mass of the second inorganic strong alkali aqueous solution dripped in the second stage accounts for 30-32% of the total mass of the second inorganic strong alkali aqueous solution, and the mass of the second inorganic strong alkali aqueous solution dripped in the third stage accounts for 38-45% of the total mass of the second inorganic strong alkali aqueous solution; in the ring-closing reaction process, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

[0045] In the present invention, the inorganic strong base in the second inorganic strong base aqueous solution preferably includes sodium hydroxide and / or potassium hydroxide, and in the embodiment, specifically sodium hydroxide. The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is preferably 45-50%. The molar ratio of the bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is preferably 0.5:(0.9-1).

[0046] In the present invention, the temperature of the ring-closing reaction is preferably 60 to 63° C. The negative pressure condition of the ring-closing reaction is preferably -78 to 80 kPa.

[0047] In the present invention, the dripping includes sequentially performing the first stage dripping, the second stage dripping and the third stage dripping, and the total time of dripping the second inorganic strong alkali aqueous solution is specifically 3h. The time of the first stage dripping, the time of the second stage dripping and the time of the third stage dripping are preferably 1h respectively. The mass percentage of the second inorganic strong alkali aqueous solution dripped in the first stage to the total mass of the second inorganic strong alkali aqueous solution is preferably 25-30%, more preferably 29%, 25%, 28% or 30%; the mass percentage of the second inorganic strong alkali aqueous solution dripped in the second stage to the total mass of the second inorganic strong alkali aqueous solution is preferably 30-32%, more preferably 32% or 30%; the mass percentage of the second inorganic strong alkali aqueous solution dripped in the third stage to the total mass of the second inorganic strong alkali aqueous solution is preferably 38-45%, more preferably 39%, 45%, 40% or 38%. Preferably, the mass of the second inorganic strong alkali aqueous solution dripped in the first stage is less than the mass of the second inorganic strong alkali aqueous solution dripped in the second stage and less than the mass of the second inorganic strong alkali aqueous solution dripped in the third stage.

[0048] In the present invention, during the ring-closing reaction, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction. The separated water is preferably separated by layers using a water separator. The ring-closing reaction ends when the dropwise addition is completed.

[0049] In the present invention, after the second inorganic strong alkali aqueous solution is added dropwise, a closed-loop reaction liquid is obtained; after the closed-loop reaction liquid is obtained, the present invention preferably further comprises: removing epichlorohydrin from the closed-loop reaction liquid to obtain a crude reaction liquid of bisphenol F epoxy resin;

[0050] The bisphenol F epoxy resin crude reaction liquid and the first organic solvent are mixed to obtain a mixed solution; a third inorganic strong alkali aqueous solution is added dropwise to the mixed solution for a refining reaction to obtain a refined reaction liquid;

[0051] The refined reaction liquid and the extraction solvent are mixed and then allowed to stand for stratification to obtain an oil phase product; the extraction solvent is the second organic solvent, or the second organic solvent and water;

[0052] The oil phase product is sequentially neutralized, washed with water and desolventized to obtain a refined product of bisphenol F epoxy resin.

[0053] The present invention removes epichlorohydrin from the closed-loop reaction liquid to obtain a crude reaction liquid of bisphenol F epoxy resin. In the present invention, the specific implementation of removing epichlorohydrin is preferably vacuum distillation, the temperature of removing epichlorohydrin is preferably 105°C, and the vacuum degree is preferably -98kPa. When the closed-loop reaction liquid is free of epichlorohydrin, the temperature is lowered to obtain a crude reaction liquid of bisphenol F epoxy resin.

[0054] After obtaining the crude reaction liquid of bisphenol F epoxy resin, the present invention mixes the crude reaction liquid of bisphenol F epoxy resin with the first organic solvent to obtain a mixed solution; and drips a third inorganic strong alkali aqueous solution into the mixed solution for a refining reaction to obtain a refined reaction liquid. In the present invention, the first organic solvent preferably includes toluene or methyl isobutyl ketone (MIBK). The inorganic strong alkali in the third inorganic strong alkali aqueous solution preferably includes sodium hydroxide and / or potassium hydroxide, and the mass percentage of the inorganic strong alkali in the third inorganic strong alkali aqueous solution used in the refining reaction is preferably 30-32%. The molar ratio of the inorganic strong alkali to the bisphenol F in the third inorganic strong alkali aqueous solution used in the refining reaction is preferably (0.14-0.15): 0.5. The temperature of the refining reaction is preferably 80-90°C, and the dripping time of the third inorganic strong alkali aqueous solution during the refining reaction is preferably 20-30min. After the dripping is completed, the heat preservation reaction is carried out, and the heat preservation reaction time of the refining reaction is preferably 1-1.5h. The heat preservation reaction time of the purification reaction is preferably calculated from the completion of the dropwise addition of the third inorganic strong alkali aqueous solution. The heat preservation reaction of the purification reaction is carried out under stirring.

[0055] After obtaining the refined reaction liquid, the present invention mixes the refined reaction liquid and the extraction solvent and then stands for stratification to obtain an oil phase product; the extraction solvent is a second organic solvent, or a second organic solvent and water. In the present invention, the second organic solvent preferably includes toluene or methyl isobutyl ketone (MIBK). When the extraction solvent is preferably a second organic solvent, the second organic solvent is preferably MIBK. When the extraction solvent is a second organic solvent and water, the second organic solvent is preferably toluene. The mass ratio of toluene to water is preferably 13:21. In the present invention, the standing for stratification obtains an aqueous phase, an oil-water transition layer and an oil layer. After obtaining the oil-water transition layer, the present invention preferably further includes filtering the oil-water transition layer to remove aged resin. The present invention preferably separates and removes aged resin from the oil-water transition layer by filtration, and then combines the oil phase obtained after filtration with the oil phase product obtained by standing for stratification.

[0056] After the oil phase product is obtained by layering, the oil phase product is sequentially neutralized, washed with water and desolventized to obtain a refined product of bisphenol F epoxy resin. The reagent used for the neutralization is preferably a sodium dihydrogen phosphate aqueous solution, and the mass percentage of sodium dihydrogen phosphate in the sodium dihydrogen phosphate aqueous solution is preferably 0.5-1%. The neutralized oil phase product obtained after the neutralization is washed with water, and the specific implementation of the desolventization is preferably negative pressure distillation.

[0057] The bisphenol F epoxy resin prepared by the invention is a linear epoxy resin with an epoxy end group.

[0058] In summary, the present invention can control the side reactions to a minimum by controlling the above two reaction stages, thereby obtaining a linear epoxy resin with a predetermined relative molecular mass and an epoxy end group.

[0059] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0060] Example 1

[0061] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this embodiment is as follows:

[0062] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) were added into the reaction bottle. During the process, nitrogen protection was used with a nitrogen flow rate of 15 L / h. The temperature was raised to 50°C with stirring, and 6.4 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.08 mol) was added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether, and the conversion rate of bisphenol F was 92.4%.

[0063] (2) Ring-closing reaction: After the insulation is completed, the nitrogen is turned off, the temperature is raised to 60°C, with a slight negative pressure of -80kPa, and 73g of sodium hydroxide aqueous solution (50wt%, NaOH 0.91mol) is added dropwise at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (21.2g is added dropwise in the first 1h, 23.4g is added dropwise in the middle 1h, and 28.4g is added dropwise in the last 1h). During the reaction, epichlorohydrin and water are kept for azeotropic distillation. After stratification by the water separator, the water is separated and the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, the temperature is slowly raised to 105°C, and the vacuum degree is adjusted to -98kPa to remove ECH. When there is basically no material, the temperature is lowered.

[0064] ⑶ Refining: add 104g of the first organic solvent toluene to the above-mentioned kettle material, stir and heat to 80°C, start to drip 19g of sodium hydroxide aqueous solution (32wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g of the second organic solvent toluene and 210g of water and stir, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and the oil phase obtained by standing and merging, then neutralize the oil layer with 0.5wt% sodium dihydrogen phosphate aqueous solution, wash the oil layer with 100g of water after stratification, and finally remove the solvent toluene from the oil layer under negative pressure to obtain a bisphenol F epoxy resin product.

[0065] Example 2

[0066] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this embodiment is as follows:

[0067] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 231.5 g (2.5 mol) were added into the reaction bottle. During the process, nitrogen protection was used at a flow rate of 20 L / h. The temperature was raised to 50°C with stirring. 6.4 g of aqueous sodium hydroxide solution (50 wt%, NaOH 0.08 mol) was added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 87.5%.

[0068] (2) Ring-closing reaction: After the insulation is completed, the nitrogen is turned off, the temperature is raised to 60°C, with a slight negative pressure of -80kPa, and 81g of sodium hydroxide aqueous solution (45wt%, NaOH 0.91mol) is added dropwise at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (20.2g is added dropwise in the first 1h, 24.3g is added dropwise in the middle 1h, and 36.5g is added dropwise in the last 1h). During the reaction, epichlorohydrin and water are kept for azeotropic distillation. After stratification by the water separator, the water is separated and the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, the temperature is slowly raised to 105°C, and the vacuum degree is adjusted to -98kPa to remove ECH. When there is basically no material, the temperature is lowered.

[0069] ⑶ Refining: add 104g toluene, a first organic solvent, to the above-mentioned kettle material, stir and heat to 80°C, start to drip 19g of sodium hydroxide aqueous solution (32wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g toluene, a second organic solvent, and stir with 210g water, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and the oil phase obtained by standing to combine, then neutralize the oil layer with 1% sodium dihydrogen phosphate aqueous solution, wash the oil layer with 100g water after stratification, and finally remove the solvent toluene from the oil layer under negative pressure to obtain a bisphenol F epoxy resin product.

[0070] Example 3

[0071] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this embodiment is as follows:

[0072] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) were added into the reaction flask. During the process, nitrogen protection was used at a flow rate of 15 L / h. The temperature was raised to 55°C with stirring. 10 g of sodium hydroxide aqueous solution (32 wt%, NaOH 0.08 mol) was added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 93.1%.

[0073] (2) Closed-loop reaction: After the insulation is completed, turn off the nitrogen, raise the temperature to 60°C, with a slight negative pressure of -80kPa, and add 73g of sodium hydroxide aqueous solution (50wt%, NaOH 0.91mol) at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (20.4g is added in the first 1h, 23.4g is added in the middle 1h, and 29.2g is added in the last 1h). During the reaction, the epichlorohydrin and water are kept azeotropically distilled, and the water is separated after stratification by the water separator. At the same time, the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, slowly raise the temperature to 105°C, adjust the vacuum degree to -98kPa to remove ECH, and cool down when there is basically no material.

[0074] (3) Refining: add 100g MIBK, a first organic solvent, to the above-mentioned kettle material, stir and heat to 80°C, start to drip 18.1g sodium hydroxide aqueous solution (32wt%, NaOH 0.14mol), take 30min, complete the dripping, keep warm and stir for 1h, add 120g MIBK, a second organic solvent, stir, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin, and combine the oil phase obtained by standing, then neutralize the oil layer with 0.5% sodium dihydrogen phosphate aqueous solution, wash the oil layer with 100g water after stratification, and finally remove the solvent MIBK from the oil layer under negative pressure to obtain the bisphenol F epoxy resin product.

[0075] Example 4

[0076] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this embodiment is as follows:

[0077] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) were added into the reaction bottle. During the process, nitrogen protection was used at a flow rate of 15 L / h. The temperature was raised to 50°C with stirring. 6.0 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.075 mol) was added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 92.7%.

[0078] (2) Closed-loop reaction: After the insulation is completed, turn off the nitrogen, raise the temperature to 63°C, with a slight negative pressure of -78kPa, and add 73g of sodium hydroxide aqueous solution (50wt%, NaOH 0.91mol) at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (21.9g is added in the first 1h, 23.4g is added in the middle 1h, and 27.7g is added in the last 1h). During the reaction, the epichlorohydrin and water are kept azeotropically distilled, and the water is separated after stratification by the water separator. At the same time, the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, slowly heat up to 105°C, adjust the vacuum degree to -98kPa to remove ECH, and cool down when there is basically no material.

[0079] ⑶ Refining: add 104g toluene, a first organic solvent, to the above-mentioned kettle material, stir and heat to 90°C, start to drip 20g sodium hydroxide aqueous solution (30wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g toluene, a second organic solvent, and stir with 210g water, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and combine the oil phase obtained by standing, then neutralize the oil layer with 0.5% sodium dihydrogen phosphate aqueous solution, wash the oil layer with 100g water after stratification, and finally remove the solvent toluene from the oil layer under negative pressure to obtain a bisphenol F epoxy resin product.

[0080] Comparative Example 1

[0081] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this comparative example is:

[0082] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin (4 mol) were added into the reaction flask. During the process, nitrogen protection was used at a flow rate of 15 L / h. The temperature was raised to 50°C with stirring. 9.4 g of aqueous sodium hydroxide solution (32 wt%, NaOH 0.08 mol) was added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 92.6%.

[0083] (2) Ring-closing reaction: After the insulation is completed, the nitrogen is turned off, the temperature is raised to 60°C, with a slight negative pressure of -80kPa, and 114g of sodium hydroxide aqueous solution (32wt%, NaOH 0.91mol) is added dropwise at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (33.2g is added dropwise in the first 1h, 36.5g is added dropwise in the middle 1h, and 44.3g is added dropwise in the last 1h). During the reaction, epichlorohydrin and water are kept for azeotropic distillation. After stratification by the water separator, the water is separated and the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, the temperature is slowly raised to 105°C, and the vacuum degree is adjusted to -98kPa to remove ECH. When there is basically no material, the temperature is lowered.

[0084] ⑶ Refining: add 104g toluene, a first organic solvent, to the above-mentioned kettle material, stir and heat to 80°C, start to drip 19g sodium hydroxide aqueous solution (32wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g toluene, a second organic solvent, and stir with 210g water, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and the oil phase obtained by standing to combine, then neutralize the oil layer with 0.5% sodium dihydrogen phosphate aqueous solution, add 100g water to wash the oil layer after stratification, and finally remove the solvent toluene from the oil layer to obtain a bisphenol F epoxy resin product.

[0085] Comparative Example 2

[0086] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this comparative example is:

[0087] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) were added into the reaction bottle. During the process, nitrogen protection was used at a flow rate of 15 L / h. The temperature was raised to 50°C with stirring. 1.76 g of benzyltrimethylammonium chloride and 6.4 g of sodium hydroxide aqueous solution (50 wt%, NaOH 0.08 mol) were added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 89.3%.

[0088] (2) Ring-closing reaction: After the insulation is completed, the nitrogen is turned off, the temperature is raised to 60°C, with a slight negative pressure of -80kPa, and 73g of sodium hydroxide aqueous solution (50wt%, NaOH 0.91mol) is added dropwise at this temperature. The dropping speed is controlled during the process, and the dropping time is 3h (21.2g is added dropwise in the first 1h, 23.4g is added dropwise in the middle 1h, and 28.4g is added dropwise in the last 1h). During the reaction, epichlorohydrin and water are kept for azeotropic distillation. After stratification by the water separator, the water is separated and the epichlorohydrin is returned to the reactor to continue to participate in the reaction. After the dropwise addition is completed, the temperature is slowly raised to 102°C, and the vacuum degree is adjusted to -98kPa to remove ECH. When there is basically no material, the temperature is lowered.

[0089] ⑶ Refining: add 104g toluene, a first organic solvent, to the above-mentioned kettle material, stir and heat to 80°C, start to drip 19g sodium hydroxide aqueous solution (32wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g toluene, a second organic solvent, and stir with 210g water, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and the oil phase obtained by standing to combine, then neutralize the oil layer with 1% sodium dihydrogen phosphate aqueous solution, add 100g water to wash the oil layer after stratification, and finally remove the solvent toluene from the oil layer to obtain the bisphenol F epoxy resin product.

[0090] Comparative Example 3

[0091] The difference from Example 1 is that the time for adding the base during the ring-closing reaction is 3 hours (adding at a constant speed during the process), and the other operations are exactly the same as in Example 1.

[0092] Comparative Example 4

[0093] The difference from Example 1 is that the time for adding alkali in the closed-loop reaction is 3 h (the amount of alkali added in the first stage is 50% of the total alkali amount in the closed-loop reaction, the amount of alkali added in the second stage is 30% of the total alkali amount in the closed-loop reaction, and the amount of alkali added in the third stage is 20% of the total alkali amount in the closed-loop reaction), and the rest of the operations are exactly the same as in Example 1.

[0094] Comparative Example 5

[0095] The difference from Example 1 is that the time for adding alkali in the closed-loop reaction is 3 h (the amount of alkali added in the first stage is 30% of the total alkali amount in the closed-loop reaction, the amount of alkali added in the second stage is 50% of the total alkali amount in the closed-loop reaction, and the amount of alkali added in the third stage is 20% of the total alkali amount in the closed-loop reaction), and the rest of the operations are exactly the same as in Example 1.

[0096] Comparative Example 6

[0097] The difference from Example 1 is that the time for adding alkali in the closed-loop reaction is 3 h (the amount of alkali added in the first stage is 20% of the total alkali amount in the closed-loop reaction, the amount of alkali added in the second stage is 30% of the total alkali amount in the closed-loop reaction, and the amount of alkali added in the third stage is 50% of the total alkali amount in the closed-loop reaction), and the remaining operations are exactly the same as in Example 1.

[0098] Comparative Example 7

[0099] The specific operation process of the preparation method of bisphenol F epoxy resin provided in this comparative example is:

[0100] (1) Ring-opening reaction: 110.8 g of 90.4% bisphenol F (0.5 mol) and 99.9% epichlorohydrin 370.4 g (4 mol) were added into the reaction bottle. During the process, nitrogen protection was used at a flow rate of 15 L / h. The temperature was raised to 50°C with stirring. 170 g of isobutyl alcohol and 6.4 g of aqueous sodium hydroxide solution (50 wt%, NaOH 0.08 mol) were added for pre-reaction. The reaction was kept at this temperature for 2 h to open the ring to generate chlorohydrin ether. The conversion rate of bisphenol F was 88.3%.

[0101] (2) Closed-loop reaction: After the insulation is completed, turn off the nitrogen, raise the temperature to 60°C, with a slight negative pressure of -80kPa, and add 73g of sodium hydroxide aqueous solution (50wt%, NaOH 0.91mol) at this temperature. Control the dropping speed during the process, and the dropping time is about 3h (21.2g is added in the first 1h, 23.4g is added in the middle 1h, and 28.4g is added in the last 1h). During the reaction, keep epichlorohydrin and water azeotropic distillation, separate the water after stratification by the water separator, and return epichlorohydrin to the reactor to continue to participate in the reaction. After the addition is completed, slowly raise the temperature to 102°C, adjust the vacuum degree to -98kPa to remove isobutanol and ECH, and cool down when there is basically no material.

[0102] ⑶ Refining: add 104g toluene, a first organic solvent, to the above-mentioned kettle material, stir and heat to 80°C, start to drip 19g sodium hydroxide aqueous solution (32wt%, NaOH 0.15mol), take 30min, complete the dripping, keep warm and stir for 1h, add 130g toluene, a second organic solvent, and stir with 210g water, let stand to separate the water layer after dissolution, filter and separate the oil-water transition layer to remove the aged resin and the oil phase obtained by standing to combine, then neutralize the oil layer with 1% sodium dihydrogen phosphate aqueous solution, add 100g water to wash the oil layer after stratification, and finally remove the solvent toluene from the oil layer to obtain the bisphenol F epoxy resin product.

[0103] Test Case

[0104] Analysis results test:

[0105] The epoxy equivalent, total chlorine, hydrolyzed chlorine, viscosity and inorganic chlorine of the products prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were tested. The specific results are shown in Table 1.

[0106] Table 1 Performance test results of products prepared in Examples 1 to 4 and Comparative Examples 1 to 7

[0107]

[0108] As shown in Table 1, compared with Example 1, the molar amount of sodium hydroxide in the sodium hydroxide aqueous solution used in step (1) and step (2) in Comparative Example 1 remains unchanged, but the mass of water therein increases, that is, the molar concentration of the strong sodium hydroxide aqueous solution used in step (1) and step (2) in Comparative Example 1 decreases. Excessive water in the reaction process promotes the hydrolysis reaction of epichlorohydrin under alkaline conditions to generate glycerol, which further reacts with the generated epoxy resin, thereby deteriorating the product quality, and ultimately resulting in an increase in the hydrolysis chlorine content, viscosity and inorganic chlorine content of the obtained bisphenol F epoxy resin product.

[0109] Compared with Example 1, in Comparative Example 2, 1.76 g of benzyltrimethylammonium chloride was added to step (1) of Comparative Example 2, resulting in an increase in the hydrolysis chlorine content, viscosity, inorganic chlorine content and moisture content of the obtained bisphenol F epoxy resin product. In addition, the addition of additives increases the wastewater treatment process, making the production cost higher.

[0110] Comparative Example 3 is compared with Example 1. In Comparative Example 3, in step (2), sodium hydroxide aqueous solution is added dropwise at a uniform rate, resulting in increased hydrolysis chlorine content, viscosity, inorganic chlorine content and moisture content of the obtained bisphenol F epoxy resin product.

[0111] Compared with Example 1, the droplet addition rate of step (2) in Comparative Examples 4 to 6 changes, resulting in an increase in the hydrolysis chlorine content, viscosity, inorganic chlorine content and water content of the obtained bisphenol F epoxy resin product.

[0112] Compared with Example 1, in Comparative Example 7, 170 g of isobutyl alcohol is further added in step (1) of Comparative Example 7. The quality of the obtained bisphenol F epoxy resin product is not much different from that of Example 1. However, the addition of solvent requires additional equipment for separating and recovering the solvent, and at the same time increases energy consumption, making the production cost of the bisphenol F epoxy resin higher.

[0113] In summary, the present invention adopts a two-step process, and the reaction does not require the addition of an auxiliary agent or solvent, thereby reducing the operation and energy consumption of separating the solvent in the later stage. By optimizing the amount of pre-reaction catalyst, the conversion rate is controlled, the hydrolysis chlorine of the crude resin is reduced, and the side reaction is reduced. In the main reaction process, a negative pressure segmented liquid alkali process is adopted, and the product quality is improved by controlling the dripping speed of the alkali and the water output.

[0114] It can be seen from the above embodiments that the present invention provides a process that is efficient, easy to operate and control, and has mild conditions. In the reaction process, an inorganic strong base (sodium hydroxide) is used as a catalyst, and no auxiliary agents such as quaternary ammonium salts need to be added. The refined separation wastewater can be treated and then electrolyzed to achieve a circular economy, green emission reduction and low carbon. The main reaction adopts a negative pressure segmented liquid alkali process, which effectively improves the alkali utilization rate, reduces raw material consumption, reduces side reactions, and improves the product performance of the epoxy resin, which is suitable for industrial production.

[0115] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing bisphenol F epoxy resin, characterized in that: The following steps are involved: In a protective gas atmosphere, bisphenol F, epichlorohydrin and a first inorganic strong base aqueous solution are mixed to carry out an etherification reaction to obtain a reaction solution containing chlorohydrin ether; Under negative pressure, a second inorganic strong alkali aqueous solution is added dropwise to the reaction solution containing the chlorohydrin ether to carry out a ring-closing reaction to obtain a bisphenol F epoxy resin; the dropping includes sequentially performing a first stage dropping, a second stage dropping and a third stage dropping, the first stage dropping time, the second stage dropping time and the third stage dropping time respectively account for 1 / 3 of the total dropping time, the mass of the second inorganic strong alkali aqueous solution added dropwise in the first stage accounts for 25-30% of the total mass of the second inorganic strong alkali aqueous solution, the mass of the second inorganic strong alkali aqueous solution added dropwise in the second stage accounts for 30-32% of the total mass of the second inorganic strong alkali aqueous solution, and the mass of the second inorganic strong alkali aqueous solution added dropwise in the third stage accounts for 38-45% of the total mass of the second inorganic strong alkali aqueous solution; during the ring-closing reaction, epichlorohydrin and water are subjected to azeotropic distillation to obtain an azeotropic distillation product; the epichlorohydrin obtained after separating water from the azeotropic distillation product is refluxed to continue the ring-closing reaction.

2. The preparation method according to claim 1, characterized in that: After the second inorganic strong alkali aqueous solution is added dropwise, a closed-loop reaction liquid is obtained, and then epichlorohydrin is removed from the closed-loop reaction liquid to obtain a crude reaction liquid of bisphenol F epoxy resin; The bisphenol F epoxy resin crude reaction liquid and the first organic solvent are mixed to obtain a mixed solution; a third inorganic strong alkali aqueous solution is added dropwise to the mixed solution for a refining reaction to obtain a refined reaction liquid; The refined reaction liquid and the extraction solvent are mixed and then allowed to stand for stratification to obtain an oil phase product; the extraction solvent is the second organic solvent, or the second organic solvent and water; The oil phase product is sequentially neutralized, washed with water and desolventized to obtain a refined product of bisphenol F epoxy resin.

3. The preparation method according to claim 1, characterized in that: The inorganic strong alkali in the first inorganic strong alkali aqueous solution includes sodium hydroxide and / or potassium hydroxide; The mass percentage of the inorganic strong base in the first inorganic strong base aqueous solution is 32-50%; The molar ratio of the inorganic strong alkali in the first inorganic strong alkali aqueous solution to the bisphenol F is 0.15-0.16:

1.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the bisphenol F to the epichlorohydrin is 0.5:(2.5-4); The protective gas is nitrogen, and the flow rate of the protective gas is 15 to 20 L / h.

5. The preparation method according to claim 1 or 3, characterized in that: The conversion rate of bisphenol F in the etherification reaction is 87-94%.

6. The preparation method according to claim 1, 3 or 4, characterized in that: The temperature of the etherification reaction is 50-55° C. and the time is 2 hours.

7. The preparation method according to claim 1, characterized in that: The temperature of the ring-closing reaction is 60-63° C.; the negative pressure condition of the ring-closing reaction is -78-80 kPa.

8. The preparation method according to claim 1 or 7, characterized in that: The inorganic strong base in the second inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; The mass percentage of the inorganic strong base in the second inorganic strong base aqueous solution is 45-50%; The total time for adding the second inorganic strong base aqueous solution is 3 hours; The molar ratio of the bisphenol F to the inorganic strong base in the second inorganic strong base aqueous solution is 0.5:(0.9-1).

9. The preparation method according to claim 2, characterized in that: The first organic solvent and the second organic solvent include toluene or methyl isobutyl ketone; The inorganic strong base in the third inorganic strong base aqueous solution includes sodium hydroxide and / or potassium hydroxide; The mass percentage of the inorganic strong base in the third inorganic strong base aqueous solution is 30-32%; The molar ratio of the inorganic strong base to the bisphenol F in the third inorganic strong base aqueous solution is (0.14-0.15):0.

5.

10. The preparation method according to claim 2 or 9, characterized in that: The temperature of the refining reaction is 80-90° C., the dripping time of the third inorganic strong alkali aqueous solution is 20-30 minutes, and the heat preservation reaction is carried out after the dripping is completed. The heat preservation reaction time of the refining reaction is 1-1.5 hours.

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