A method for synthesizing a low total chlorine type epoxy resin

Abstract

The present application relates to a kind of low total chlorine type epoxy resin synthesis method, belong to epoxy resin preparation technical field.The present application provides a kind of low total chlorine type epoxy resin synthesis method, comprising the following steps: binary phenolic compound and epichlorohydrin are carried out ring-opening reaction in the mixed organic solvent under the action of alkali metal hydroxide;The mixed organic solvent is composed of ketone solvent and ether solvent, the ketone solvent is diisobutyl ketone, the ether solvent is butyl ether and / or branched ether compound;Then the system after ring-opening reaction and alkali metal hydroxide solution are mixed to react, to make ring-opening reaction product carry out ring-closing reaction;Finally, the system after ring-closing reaction is purified, and low total chlorine type epoxy resin is obtained.

Description

Technical Field

[0001] This invention relates to a method for synthesizing low-total-chlorine epoxy resin, belonging to the field of epoxy resin preparation technology. Background Technology

[0002] Epoxy resin has excellent physical, mechanical, and electrical insulation properties, good adhesion to various materials, and flexibility in its application processes; therefore, it can be applied to industries such as coatings, composite materials, electronic packaging, casting materials, adhesives, molding materials, and injection molding materials, and is widely used in various sectors of the national economy.

[0003] In industries such as electronic and electrical packaging, excessive chlorine content in epoxy resin can affect the electrical properties, corrosion resistance, and heat resistance of the cured resin, leading to a decrease in the reliability of electronic components.

[0004] The total chlorine in epoxy resin includes inorganic chlorine and organic chlorine, with inorganic chlorine mainly composed of Cl. - Inorganic chlorine exists in the resin, and its content can be reduced by washing with water. Organic chlorine, however, exists as functional groups within organic molecules. Organic chlorine includes both active and inactive chlorine. Active chlorine content can be reduced by alkali purification, while inactive chlorine content cannot be reduced by alkali purification because it mainly exists in byproducts generated during the reaction. Therefore, reducing total chlorine content primarily involves reducing inactive chlorine content, which is only present in byproducts. Reducing byproducts during the reaction effectively controls the total chlorine content. Taking bisphenol A type epoxy resin as an example, the structure of the bisphenol A type epoxy resin monomer is as follows... Figure 1 As shown, the active and non-active chlorine produced in the synthesis of bisphenol A type epoxy resin are as follows: Figure 2 As shown.

[0005] However, the total chlorine content in currently prepared epoxy resins is relatively high, typically around 1600 ppm, requiring rigorous impurity removal and purification processes to prepare low-total-chlorine epoxy resins. Therefore, it is necessary to provide a method for synthesizing low-total-chlorine epoxy resins. Summary of the Invention

[0006] The purpose of this invention is to provide a method for synthesizing low-total-chlorine epoxy resin, in order to solve the problem that the currently prepared bisphenol A type epoxy resin has a high total chlorine content due to excessive by-products.

[0007] This invention provides a method for synthesizing low-total-chlorine epoxy resin, comprising the following steps:

[0008] (1) the binary phenolic compound and the epichlorohydrin are subjected to ring-opening reaction in the presence of alkali metal hydroxide in mixed organic solvent; the mixed organic solvent is composed of ketone solvent and ether solvent with a mass ratio of 0.5-1:0.5-1, the ketone solvent is diisobutyl ketone, and the ether solvent is butyl ether or is composed of butyl ether and branched ether compound with a mass ratio of 1:0.15-0.3, and the chemical structure of the branched ether compound is as follows:

[0009] ;

[0010] (2) the ring-opening reaction product is subjected to ring-closing reaction by mixing the ring-opening reaction system with alkali metal hydroxide solution;

[0011] (3) the ring-closing reaction system is subjected to impurity removal and purification to obtain low total chlorine type epoxy resin.

[0012] Preferably, the mass ratio of diisobutyl ketone and epichlorohydrin is 0.2-0.4:1.

[0013] Preferably, the molar ratio of the binary phenolic compound and the epichlorohydrin is 1:4-9.

[0014] Preferably, in step (1), the molar ratio of the binary phenolic compound and the alkali metal hydroxide is 1:0.005-0.10; the ring-opening reaction temperature is 40-80℃, and the reaction time is 1-6h.

[0015] Preferably, the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the binary phenolic compound is 1-2.5:1.

[0016] Preferably, the mixing reaction of the ring-opening reaction system and the alkali metal hydroxide solution is carried out under a vacuum degree of 5-30kpa.

[0017] Preferably, the binary phenolic compound is bisphenol A, and the alkali metal hydroxide is sodium hydroxide.

[0018] Preferably, the method for removing impurities and purifying the ring-closing reaction system is as follows: the ring-closing reaction system is subjected to vacuum distillation to remove epichlorohydrin and mixed organic solvent to obtain crude product, and then the crude product is subjected to hydrolysis chlorine removal to obtain low total chlorine type epoxy resin.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] The present application adds a mixed solvent composed of a ketone solvent and an ether solvent in the process of synthesizing a conventional epoxy resin. When a dihydric phenolic compound and an epichlorohydrin are subjected to an opening ring reaction in the mixed solvent, the mixed solvent can effectively reduce the occurrence of side reactions and improve the reaction selectivity. When the opening ring reaction product is subjected to a closing ring reaction in the mixed solvent, the mixed solvent is slightly soluble in water, which can play a transition role between the oil phase (the opening ring reaction product) and the water phase (an alkali metal hydroxide solution), thereby promoting the chemical reaction between the two phases, reducing the generation of by-products and lowering the total chlorine content. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A chemical structure diagram of a bisphenol A type epoxy resin monomer;

[0022] Figure 2 A chemical structure diagram of active chlorine and inactive chlorine generated in the synthesis of a bisphenol A type epoxy resin;

[0023] Figure 3 A nuclear magnetic hydrogen spectrum diagram of the branched ether compound prepared in the present application. DETAILED DESCRIPTION

[0024] The following examples are intended to further illustrate the present application, but not to limit the scope of protection of the present application.

[0025] The preparation method of the branched ether compound in Examples 3-6 of the present application is as follows: a toluene solution of sodium tert-pentoxide with a mass fraction of 45% is added to a reaction kettle, dry nitrogen is then introduced into the reaction kettle, 1-bromo-2-methylpropane (the molar ratio of 1-bromo-2-methylpropane to sodium tert-pentoxide is 1.1:1) is then added to the reaction kettle, heated to 85°C, stirred for 2h, cooled to room temperature, filtered, the filtrate is rotary evaporated to remove toluene and unreacted 1-bromo-2-methylpropane, and a crude product is obtained, the crude product is subjected to column chromatography purification with a mixed solvent of n-hexane and dichloromethane in a volume ratio of 3:1 to obtain a branched ether compound, the nuclear magnetic hydrogen spectrum diagram of the branched ether compound is shown in Figure 3 , and the chemical structure is as follows: .

[0026] Example 1

[0027] The synthesis method of the low total chlorine type epoxy resin of the present example comprises the following steps:

[0028] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 92.5 g of diisobutyl ketone and 92.5 g of butyl ether into a reaction kettle, stir and heat to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then heat the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0029] (2) After the etherification reaction stage is completed, heat the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, heat the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0030] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time heat the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone and butyl ether, to obtain a crude epoxy resin product.

[0031] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand and separate, then wash the organic phase obtained by the separation with deionized water twice, with 80 g of deionized water used for each washing, and finally heat the washed organic phase to 150°C under a vacuum of 10 kPa to evaporate and recover the toluene until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0032] Example 2

[0033] The low total chlorine type epoxy resin synthesis method of this example includes the following steps:

[0034] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 115.6 g of diisobutyl ketone and 115.6 g of butyl ether into a reaction kettle, stir to warm up to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then warm up the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0035] (2) After the etherification reaction stage is completed, warm up the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, warm up the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under the action of vacuum.

[0036] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time warm up the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone and butyl ether, to obtain a crude epoxy resin product.

[0037] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir to react, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand to separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing, and finally evaporate and recover the toluene from the washed organic phase by heating to 150°C under a vacuum of 10 kPa until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0038] Example 3

[0039] The low total chlorine type epoxy resin synthesis method of this example comprises the following steps:

[0040] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 92.5 g of diisobutyl ketone, 69.5 g of butyl ether and 23 g of branched ether compound into a reaction kettle, stir and heat to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then heat the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0041] (2) After the etherification reaction stage is completed, heat the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, heat the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0042] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time heat the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone, butyl ether and branched ether compound, to obtain a crude epoxy resin product.

[0043] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand and separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing, and finally heat the washed organic phase to 150°C under a vacuum of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0044] Example 4

[0045] The low total chlorine type epoxy resin synthesis method of the present example comprises the following steps:

[0046] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 92.5 g of diisobutyl ketone, 79.5 g of butyl ether and 13 g of branched ether compound into a reaction kettle, stir and heat to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then heat the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0047] (2) After the etherification reaction stage is completed, heat the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, heat the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0048] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time heat the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone, butyl ether and branched ether compound, to obtain a crude epoxy resin product.

[0049] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand and separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing, and finally heat the washed organic phase to 150°C under a vacuum of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0050] Example 5

[0051] The low total chlorine type epoxy resin synthesis method of this example includes the following steps:

[0052] (1) Add 228g of bisphenol A, 462.5g of epichlorohydrin, 115.6g of diisobutyl ketone, 86.7g of butyl ether and 28.9g of branched ether compounds to a reaction vessel, stir and heat to 50°C until bisphenol A is fully dissolved, then add 2g of sodium hydroxide to the reaction vessel, and then heat the material in the reaction vessel to 60°C and stir for 1.5h. The reaction in this step is the etherification reaction stage, that is, the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to generate a chlorohydrin intermediate.

[0053] (2) After the etherification reaction stage is completed, the temperature of the material in the reactor is raised to 65°C, and 155g of 50% sodium hydroxide solution is added dropwise to the reactor for 3.5h. After the addition is completed, the temperature of the material in the reactor is raised to 70°C, and the vacuum degree in the reactor is adjusted to 10kPa. The reaction is stirred under vacuum for 0.5h. The reaction in this step is a closed-loop reaction, i.e. the epoxidation stage. During the reaction, the chlorohydrin intermediate is dehydrated under the catalysis of sodium hydroxide to form a new epoxy group. HCl and sodium hydroxide react to generate sodium chloride and water. Part of the water and part of the excess epichlorohydrin generated in the reaction are removed under vacuum.

[0054] (3) After the closed-loop reaction is completed, the vacuum degree in the reactor is maintained at 10 kPa, and the temperature of the material in the reactor is raised to 150°C to remove excess epichlorohydrin, diisobutyl ketone, butyl ether and branched ether compounds to obtain crude epoxy resin.

[0055] (4) Add 200g of toluene to the reactor to fully dissolve the crude epoxy resin product. Then add 14.1g of 50% sodium hydroxide solution to the reactor and heat to 65°C for stirring reaction. At the same time, measure the hydrolytic chlorine content of the epoxy resin in the reactor every 0.5h until the hydrolytic chlorine content reaches 50ppm. After the reaction is completed, add 30% phosphoric acid solution to the reactor until the pH of the material in the reactor is 7. Then add 250g of deionized water to the reactor and stir for 10min. Let stand and separate the liquid. Wash the organic phase obtained by separation with deionized water twice. The mass of deionized water used for each wash is 80g. Finally, heat the washed organic phase to 150°C under a vacuum of 10kpa to evaporate and recover toluene until the toluene content in the product reaches 100ppm to obtain the low total chlorine epoxy resin product.

[0056] Example 6

[0057] The method for synthesizing low-total-chlorine epoxy resin in this embodiment includes the following steps:

[0058] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 115.6 g of diisobutyl ketone, 99.1 g of butyl ether and 16.5 g of branched ether compound into a reaction kettle, stir and heat to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then heat the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, that is, the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0059] (2) After the etherification reaction stage is completed, heat the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution to the reaction kettle dropwise, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, heat the material in the reaction kettle to 70°C, and at the same time, adjust the vacuum in the reaction kettle to 10 kPa. Stir under vacuum for 0.5 h. In this step, the reaction is a ring closure reaction, that is, an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0060] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time, heat the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone, butyl ether and branched ether compound, to obtain a crude epoxy resin product.

[0061] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir, and at the same time, measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7. Then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand and separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing. Finally, evaporate and recover the toluene from the washed organic phase by heating to 150°C under a vacuum of 10 kPa until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0062] Comparative Example 1

[0063] The synthesis method of the low total chlorine type epoxy resin of the present comparative example comprises the following steps:

[0064] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 23.1 g of diisobutyl ketone and 23.1 g of butyl ether into a reaction kettle, stir to warm up to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then warm up the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0065] (2) After the etherification reaction stage is completed, warm up the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, warm up the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0066] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time warm up the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone and butyl ether, to obtain a crude epoxy resin product.

[0067] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir to react, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand to separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing, and finally evaporate and recover the toluene from the washed organic phase by heating to 150°C under a vacuum of 10 kPa until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0068] Comparative Example 2

[0069] The synthesis method of the low total chlorine type epoxy resin of the present comparative example comprises the following steps:

[0070] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 69.4 g of diisobutyl ketone and 69.4 g of butyl ether into a reaction kettle, stir to warm up to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then warm up the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0071] (2) After the etherification reaction stage is completed, warm up the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, with a dropwise addition time of 3.5 h. After the dropwise addition is completed, warm up the material in the reaction kettle to 70°C, and at the same time adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group. HCl and sodium hydroxide react to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under the action of vacuum.

[0072] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time warm up the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone and butyl ether, to obtain a crude epoxy resin product.

[0073] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir to react, and at the same time measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand to separate, then wash the organic phase obtained by separation with deionized water twice, with 80 g of deionized water used for each washing, and finally evaporate and recover the toluene from the washed organic phase by heating to 150°C under a vacuum of 10 kPa until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0074] Comparative Example 3

[0075] The synthesis method of the low total chlorine type epoxy resin of the present comparative example comprises the following steps:

[0076] (1) Put 228 g of bisphenol A, 462.5 g of epichlorohydrin, 231.3 g of diisobutyl ketone and 231.3 g of butyl ether into a reaction kettle, stir and heat to 50°C until the bisphenol A is fully dissolved, then add 2 g of sodium hydroxide to the reaction kettle, and then heat the material in the reaction kettle to 60°C, and stir for 1.5 h. In this step, the reaction is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0077] (2) After the etherification reaction stage is completed, heat the material in the reaction kettle to 65°C, then add 155 g of a 50% by mass sodium hydroxide solution dropwise into the reaction kettle, the dropwise addition time is 3.5 h, after the dropwise addition is completed, heat the material in the reaction kettle to 70°C, and at the same time, adjust the vacuum in the reaction kettle to 10 kPa, and stir for 0.5 h under vacuum. In this step, the reaction is a ring closure reaction, i.e. an epoxidation stage. During the reaction, the chlorohydrin intermediate is catalyzed by sodium hydroxide to remove HCl to form a new epoxy group, and HCl reacts with sodium hydroxide to form sodium chloride and water. Part of the water produced by the reaction and part of the excess epichlorohydrin are removed under vacuum.

[0078] (3) After the ring closure reaction is completed, continue to maintain the vacuum in the reaction kettle at 10 kPa, and at the same time, heat the material in the reaction kettle to 150°C to remove the remaining excess epichlorohydrin, diisobutyl ketone and butyl ether, to obtain a crude epoxy resin product.

[0079] (4) Add 200 g of toluene to the reaction kettle to fully dissolve the crude epoxy resin product, then add 14.1 g of a 50% by mass sodium hydroxide solution to the reaction kettle, heat to 65°C and stir, and at the same time, measure the hydrolytic chlorine content of the epoxy resin in the reaction kettle every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, and then the reaction is completed. Add a 30% by mass phosphoric acid solution to the reaction kettle until the pH of the material in the reaction kettle is 7, then add 250 g of deionized water to the reaction kettle, stir and mix for 10 min, stand and separate, then wash the organic phase obtained by separation with deionized water twice, each time using 80 g of deionized water, and finally heat the washed organic phase to 150°C under a vacuum of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0080] Comparative Example 4

[0081] The difference between the low total chlorine type epoxy resin synthesis method of this comparative example and the low total chlorine type epoxy resin synthesis method of Example 3 is that in step (1) of the low total chlorine type epoxy resin synthesis method of this comparative example, diisobutyl ketone is replaced by methyl isobutyl ketone.

[0082] Comparative Example 5

[0083] The low total chlorine type epoxy resin synthesis method of the present comparative example is only different from the low total chlorine type epoxy resin synthesis method of Example 3 in that the diisobutyl ketone is replaced by diisopropyl ketone in step (1) of the low total chlorine type epoxy resin synthesis method of the present comparative example.

[0084] Comparative Example 6

[0085] The low total chlorine type epoxy resin synthesis method of the present comparative example is only different from the low total chlorine type epoxy resin synthesis method of Example 3 in that the diisobutyl ketone is replaced by dipentyl ketone in step (1) of the low total chlorine type epoxy resin synthesis method of the present comparative example.

[0086] Comparative Example 7

[0087] The low total chlorine type epoxy resin synthesis method of the present comparative example is only different from the low total chlorine type epoxy resin synthesis method of Example 3 in that the butyl ether is replaced by propyl ether in step (1) of the low total chlorine type epoxy resin synthesis method of the present comparative example.

[0088] Comparative Example 8

[0089] The low total chlorine type epoxy resin synthesis method of the present comparative example is only different from the low total chlorine type epoxy resin synthesis method of Example 3 in that the butyl ether is replaced by amyl ether in step (1) of the low total chlorine type epoxy resin synthesis method of the present comparative example.

[0090] Comparative Example 9

[0091] The low total chlorine type epoxy resin synthesis method of the present comparative example is only different from the low total chlorine type epoxy resin synthesis method of Example 3 in that the branched ether compound in step (1) of the low total chlorine type epoxy resin synthesis method of the present comparative example is isobutyl tert-butyl ether, and the chemical structure of isobutyl tert-butyl ether is as follows: .

[0092] Comparative Example 10

[0093] The low total chlorine type epoxy resin synthesis method of the present comparative example comprises the following steps:

[0094] (1) 228 g of bisphenol A, 462.5 g of epichlorohydrin and 185 g of diisobutyl ketone are added into a reaction kettle, and the temperature is stirred to 50°C until the bisphenol A is fully dissolved, then 2 g of sodium hydroxide is added into the reaction kettle, and the temperature of the material in the reaction kettle is raised to 60°C, and the reaction is stirred for 1.5 h. In this step, the reaction is the etherification reaction stage, that is, the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0095] (2) After the etherification reaction stage is completed, the temperature of the material in the reaction kettle is raised to 65°C, and 155 g of a 50% by mass sodium hydroxide solution is added dropwise into the reaction kettle, the dropwise addition time being 3.5 h, after the dropwise addition is completed, the temperature of the material in the reaction kettle is raised to 70°C, and at the same time, the vacuum degree in the reaction kettle is adjusted to 10 kPa, the reaction is stirred under vacuum for 0.5 h, the reaction in this step is a ring closure reaction, i.e. the epoxidation stage, in the reaction process, the chlorohydrin intermediate is removed from HCl to form a new epoxy group under the catalysis of sodium hydroxide, HCl and sodium hydroxide react to form sodium chloride and water, and part of the generated water and part of the excess epichlorohydrin are removed under the action of vacuum.

[0096] (3) After the ring closure reaction is completed, the vacuum degree in the reaction kettle is continuously maintained at 10 kPa, and at the same time, the temperature of the material in the reaction kettle is raised to 150°C, to remove the remaining excess epichlorohydrin and diisobutyl ketone, to obtain the crude epoxy resin product.

[0097] (4) 200 g of toluene is added to the reaction kettle, the crude epoxy resin product is fully dissolved, then 14.1 g of a 50% by mass sodium hydroxide solution is added to the reaction kettle, heated to 65°C for stirring reaction, and at the same time, the hydrolytic chlorine content of the epoxy resin in the reaction kettle is measured every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, the reaction is completed, a 30% by mass phosphoric acid solution is added to the reaction kettle until the pH of the material in the reaction kettle is 7, then 250 g of deionized water is added to the reaction kettle, stirred and mixed for 10 min, and then allowed to stand and separate, the organic phase obtained by separation is washed with deionized water for 2 times, the mass of deionized water used for each washing being 80 g, and finally the washed organic phase is heated to 150°C under a vacuum degree of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, to obtain the low total chlorine type epoxy resin finished product.

[0098] Comparative Example 11

[0099] The synthesis method of the low total chlorine type epoxy resin of the present comparative example comprises the following steps:

[0100] (1) 228 g of bisphenol A, 462.5 g of epichlorohydrin and 185 g of butyl ether are added to the reaction kettle, the temperature is raised to 50°C under stirring until the bisphenol A is fully dissolved, then 2 g of sodium hydroxide is added to the reaction kettle, and the temperature of the material in the reaction kettle is raised to 60°C, and stirred for 1.5 h, the reaction in this step is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0101] (2) After the etherification reaction stage is completed, the temperature of the material in the reaction kettle is raised to 65°C, and 155 g of a 50% by mass sodium hydroxide solution is added dropwise into the reaction kettle, the dropwise addition time being 3.5 h, after the dropwise addition is completed, the temperature of the material in the reaction kettle is raised to 70°C, and at the same time, the vacuum degree in the reaction kettle is adjusted to 10 kPa, the reaction is stirred for 0.5 h under vacuum, the reaction in this step is a ring closure reaction, i.e. an epoxidation stage, in the reaction process, the chlorohydrin intermediate is removed to form a new epoxy group under the catalysis of sodium hydroxide, HCl and sodium hydroxide react to form sodium chloride and water, and part of the generated water and part of the excess epichlorohydrin are removed under the action of vacuum.

[0102] (3) After the ring closure reaction is completed, the vacuum degree in the reaction kettle is continuously maintained at 10 kPa, and at the same time, the temperature of the material in the reaction kettle is raised to 150°C, to remove the remaining excess epichlorohydrin and butyl ether, to obtain a crude epoxy resin product.

[0103] (4) 200 g of toluene is added to the reaction kettle, the crude epoxy resin product is fully dissolved, then 14.1 g of a 50% by mass sodium hydroxide solution is added to the reaction kettle, heated to 65°C and stirred, at the same time, the hydrolytic chlorine content of the epoxy resin in the reaction kettle is measured every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, the reaction is completed, a 30% by mass phosphoric acid solution is added to the reaction kettle until the pH of the material in the reaction kettle is 7, then 250 g of deionized water is added to the reaction kettle, stirred and mixed for 10 min, allowed to stand and separate, the organic phase obtained by the separation is washed with deionized water for 2 times, the mass of deionized water used for each washing being 80 g, finally, the washed organic phase is heated to 150°C under a vacuum degree of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, to obtain a low total chlorine type epoxy resin finished product.

[0104] Comparative Example 12

[0105] The synthesis method of the low total chlorine type epoxy resin of the present comparative example comprises the following steps:

[0106] (1) 228 g of bisphenol A and 462.5 g of epichlorohydrin are added to the reaction kettle, the temperature is raised to 50°C to fully dissolve the bisphenol A, then 2 g of sodium hydroxide is added to the reaction kettle, and the temperature of the material in the reaction kettle is raised to 60°C, and stirred for 1.5 h, the reaction in this step is an etherification reaction stage, i.e. the phenolic hydroxyl group of bisphenol A reacts with the epoxy group of epichlorohydrin to form a chlorohydrin intermediate.

[0107] (2) After the etherification reaction stage is completed, the temperature of the material in the reaction kettle is raised to 65°C, and 155 g of a 50% by mass sodium hydroxide solution is added dropwise into the reaction kettle, the dropwise addition time being 3.5 h, after the dropwise addition is completed, the temperature of the material in the reaction kettle is raised to 70°C, and at the same time, the vacuum degree in the reaction kettle is adjusted to 10 kPa, the reaction is stirred for 0.5 h under vacuum, the reaction in this step is a ring closure reaction, i.e. an epoxidation stage, in the reaction process, the chlorohydrin intermediate is removed of HCl to form a new epoxy group under the catalysis of sodium hydroxide, HCl and sodium hydroxide react to form sodium chloride and water, and part of the generated water and part of the excess epichlorohydrin are removed under the action of vacuum.

[0108] (3) After the ring closure reaction is completed, the vacuum degree in the reaction kettle is continuously maintained at 10 kPa, and at the same time, the temperature of the material in the reaction kettle is raised to 150°C, the remaining excess epichlorohydrin is removed, and a crude epoxy resin product is obtained.

[0109] (4) 200 g of toluene is added into the reaction kettle, the crude epoxy resin product is fully dissolved, then 14.1 g of a 50% by mass sodium hydroxide solution is added into the reaction kettle, heated to 65°C and stirred, at the same time, the hydrolytic chlorine content of the epoxy resin in the reaction kettle is determined once every 0.5 h until the hydrolytic chlorine content reaches 50 ppm, the reaction is completed, a 30% by mass phosphoric acid solution is added into the reaction kettle until the pH of the material in the reaction kettle is 7, then 250 g of deionized water is added into the reaction kettle, stirred and mixed for 10 min, and then allowed to stand and separate, the organic phase obtained by the separation is washed with deionized water for 2 times, the deionized water used for each washing is 80 g in mass, finally, the washed organic phase is heated to 150°C under a vacuum degree of 10 kPa to evaporate and recover toluene until the toluene content in the product reaches 100 ppm, and a low total chlorine type epoxy resin finished product is obtained.

[0110] Experimental Example

[0111] In order to evaluate the total chlorine content difference of the epoxy resins synthesized by the low total chlorine type epoxy resin synthesis methods of the examples and the comparative examples, the total chlorine content of the epoxy resins is respectively tested according to the method in the standard GB / T 12007.3-1989 "Determination method of total chlorine content of epoxy resin", and the results are shown in Table 1.

[0112] Table 1 Total chlorine content of the epoxy resins synthesized by the examples and the comparative examples

[0113] Synthesis method Total chlorine content (ppm) Synthesis method Total chlorine content (ppm) Example 1 887 Comparative Example 4 1028 Example 2 742 Comparative Example 5 1107 Example 3 116 Comparative Example 6 1011 Example 4 109 Comparative Example 7 1056 Example 5 113 Comparative Example 8 1130 Example 6 118 Comparative Example 9 995 Comparative Example 1 1353 Comparative Example 10 1253 Comparative Example 2 1124 Comparative Example 11 1186 Comparative Example 3 1064 Comparative Example 12 1572

[0114] As shown in Table 1, the total chlorine content of the epoxy resins prepared by the examples 1-6 of the present application is less than 1000 ppm, which indicates that the epoxy resin synthesis method of the present application can effectively reduce the by-products in the reaction process, and improve the purity and quality of the epoxy resin.

[0115] From Examples 1-2 and Comparative Examples 1-3, it can be seen that as the amount of diisobutyl ketone and butyl ether in the system increases, the total chlorine content of the epoxy resin shows a trend of first decreasing and then increasing, indicating that when the mass ratio of diisobutyl ketone to epichlorohydrin in the system is greater than or equal to 0.2:1 and less than 0.5:1, the total chlorine content of the synthesized epoxy resin is low, and when the mass ratio of diisobutyl ketone to epichlorohydrin is less than 0.2:1 or greater than 0.5:1, the total chlorine content of the synthesized epoxy resin increases. This may be because when the amount of diisobutyl ketone and butyl ether is too low or too high, it will affect the transition role of the mixed solvent in the water phase and the oil phase, and thus cannot effectively promote the chemical reaction between the two phases during the reaction process, resulting in the generation of by-products and an increase in the total chlorine content.

[0116] From Examples 1 and 3-6, it can be seen that when branched ether compounds are added to the system, the total chlorine content of the synthesized epoxy resin is further reduced, indicating that branched ether compounds can further promote the transition role of the mixed solvent in the water phase and the oil phase, and thus promote the chemical reaction between the two phases, reduce the generation of by-products, and reduce the total chlorine content.

[0117] From Examples 3 and Comparative Examples 4-9, it can be seen that when the structure of the ketone solvent, the structure of the ether solvent, or the structure of the branched ether compound in the mixed solvent is changed, the total chlorine content of the synthesized epoxy resin increases, indicating that the structure of the ketone solvent, the ether solvent, and the branched ether compound in the mixed solvent has an important influence on the reduction of by-products during the synthesis of the epoxy resin, which may be due to the polarity, lipophilicity, density, and steric hindrance of the solvent.

[0118] From Examples 1 and Comparative Examples 10-11, it can be seen that when only diisobutyl ketone or butyl ether is used, the total chlorine content of the synthesized epoxy resin increases, indicating that diisobutyl ketone and butyl ether both play a role in reducing by-products during the synthesis of the epoxy resin, and neither can be omitted.

[0119] From Examples 1 and Comparative Example 12, it can be seen that when no diisobutyl ketone and butyl ether mixed solvent is added to the system, the total chlorine content of the synthesized epoxy resin reaches 1572 ppm, again proving that the mixed solvent can reduce by-products during the synthesis of the epoxy resin, and thus reduce the total chlorine content.

Claims

1. A method for synthesizing a low total chlorine type epoxy resin, characterized by, The method comprises the following steps: (1) the ring-opening reaction of a binary phenolic compound and epichlorohydrin in a mixed organic solvent under the action of an alkali metal hydroxide; the mixed organic solvent is composed of a ketone solvent and an ether solvent in a mass ratio of 0.5-1:0.5-1, the ketone solvent is diisobutyl ketone, the ether solvent is butyl ether or is composed of butyl ether and a branched ether compound in a mass ratio of 1:0.15-0.3, the mass ratio of the diisobutyl ketone and the epichlorohydrin is 0.2-0.4:1, and the branched ether compound has the following chemical structure: ; (2) mixing the system after the ring-opening reaction with an alkali metal hydroxide solution to perform a ring-closing reaction on the ring-opening reaction product; (3) purifying the system after the ring-closing reaction to obtain the low-total-chlorine epoxy resin.

2. The method of synthesizing a low total chlorine type epoxy resin according to claim 1, wherein The molar ratio of the diphenolic compound to the epichlorohydrin is 1:4-9.

3. The method of claim 1 or 2, wherein the total chlorine type epoxy resin is a low total chlorine type epoxy resin. In step (1), the molar ratio of the diphenolic compound to the alkali metal hydroxide is 1:0.005-0.10; the ring-opening reaction is performed at a temperature of 40-80°C for 1-6 hours.

4. The method of claim 1 or 2, wherein the total chlorine type epoxy resin is a low total chlorine type epoxy resin. In step (2), the molar ratio of the alkali metal hydroxide in the alkali metal hydroxide solution to the diphenolic compound is 1-2.5:

1.

5. The method of synthesizing a low total chlorine type epoxy resin according to claim 1 or 2, wherein The mixing reaction of the system after the ring-opening reaction with the alkali metal hydroxide solution is performed under a vacuum degree of 5-30 kPa.

6. The method of synthesizing a low total chlorine type epoxy resin according to claim 1 or 2, wherein The diphenolic compound is bisphenol A, and the alkali metal hydroxide is sodium hydroxide.

7. The method of synthesizing a low total chlorine type epoxy resin according to claim 1 or 2, wherein The method for purifying the system after the ring-closing reaction is as follows: the system after the ring-closing reaction is distilled under reduced pressure to remove the epichlorohydrin and the mixed organic solvent, and a crude product is obtained; then the crude product is subjected to hydrolysis chlorine removal to obtain the low-total-chlorine epoxy resin.

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