Preparation process of high-performance phenoxy resin

Abstract

The invention discloses a preparation process of high-performance phenoxy resin, and belongs to the technical field of phenoxy resin preparation. The preparation process of the phenoxy resin comprises the following steps: (1) adding an epoxy compound, a chain extender and NMP (N-Methyl Pyrrolidone) into a reaction kettle, stirring, heating, adding a catalyst under the protection of nitrogen, and heating to react to obtain a resin solution; (2) extruding the resin solution through an extruder, then drawing and pelletizing, and controlling the pelletizing temperature to be 50-80 DEG C; (3) freezing the particles by liquid nitrogen, and crushing to obtain powder; and (4) blowing the powder into a fluidized bed evaporator through high-pressure and high-temperature nitrogen, condensing and recovering NMP, collecting a high-temperature viscous material, extruding by a twin-screw extruder, and then, carrying out bracing and pelletizing to obtain phenoxy resin particles. The phenoxy resin prepared by the invention has higher molecular weight and tensile strength, has important application value, and can realize controllable synthesis of molecular weight by changing reaction time.

Description

Technical Field

[0001] The present invention relates to the technical field of phenoxy resin preparation, in particular to a preparation process of high-performance phenoxy resin. Background Art

[0002] Phenoxy resin, also known as phenoloxy resin or polyhydroxy ether, is a transparent or amorphous polymer material. It is a thermoplastic resin produced by the ring-opening polycondensation reaction of epoxy resin with phenolic or amine compounds. While its structure is essentially the same as that of conventional epoxy resin, its structure has a significantly higher degree of polymerization, resulting in a relatively high molecular weight. Due to its excellent mechanical strength, chemical resistance, and environmental friendliness, it has important applications in electronic packaging, composite materials, and environmentally friendly coatings. Traditionally, phenoxy resins have been prepared by directly reacting bisphenols (such as bisphenol A and bisphenol F) with epichlorohydrin or by reacting low-functionality epoxy resins (such as bisphenol A-type epoxy resins) with excess phenolic compounds in a solvent. However, their low molecular weight and difficult post-processing limit their application in high-strength, high-toughness applications.

[0003] Chinese invention patent publication number CN104356355A discloses a high-toughness epoxy resin, its preparation method, and application. The synthesis reaction is carried out in a solvent-free state, the synthesis reaction speed is fast, and the reaction temperature is low. The epoxy resin of the invention has the characteristics of low viscosity, and the prepared coating has a fast curing speed, but its molecular weight is relatively low. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a method for preparing phenoxy resin and a process thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A preparation process for a high-performance phenoxy resin comprises the following steps: (1) Add epoxy compound, chain extender and NMP (N-methylpyrrolidone) into the reactor and stir, heat to 120-140°C, add catalyst under nitrogen protection, heat to 130-150°C, and react for 3-5 hours to obtain resin solution; (2) The resin solution is extruded through an extruder and then pelletized. The pelletizing temperature is controlled at 50-80°C to obtain pellets with a diameter of 1-3 mm. (3) After freezing the particles in liquid nitrogen (-196°C), grinding them with a pulverizer to control the particle size to 1000-3000 mesh to obtain a powder; (4) The powder is blown into a fluidized bed evaporator by high-pressure and high-temperature nitrogen (pressure 0.5-1.0 MPa, temperature 260°C), and NMP is evaporated and condensed for recovery. The high-temperature viscous material is collected, extruded through a twin-screw extruder, and then stretched and pelletized to obtain phenoxy resin particles; The catalyst is prepared by reacting N-vinylimidazole with 4-(2-aminoethoxy)phenol to generate 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol, which is then reacted with 4-chlorophthalic anhydride to generate a diimidazolephthalic anhydride compound, and finally reacted with a boron trifluoride-ether solution.

[0006] The catalyst is prepared by the following method: S1: N-vinylimidazole reacts with 4-(2-aminoethoxy)phenol to generate 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol; the reaction structure is as follows: .

[0007] S2: 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol reacts with 4-chlorophthalic anhydride to form a diimidazolephthalic anhydride compound; the reaction structure is as follows: .

[0008] S3: A diimidazole phthalic anhydride compound reacts with a boron trifluoride-ether solution to obtain a catalyst; the reaction structure is as follows: .

[0009] The molar ratio of N-vinylimidazole to 4-(2-aminoethoxy)phenol in step S1 is (2-2.5):1.

[0010] In step S2, the molar ratio of 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol to 4-chlorophthalic anhydride is 1:(1-1.2).

[0011] The molar ratio of the diimidazole phthalic anhydride compound to the boron trifluoride-ether solution in step S3 is 1:(2-2.4).

[0012] The epoxy compound is an epoxy resin or a combination of an epoxy resin and glycidyl ether.

[0013] The epoxy resin is a mixture of one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and bisphenol H epoxy resin; the glycidyl ether is a mixture of one or more of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, hexanediol diglycidyl ether, polypropylene glycol diglycidyl ether, and 1,4-cyclohexanedimethanol diglycidyl ether.

[0014] The chain extender is a mixture of one or more of bisphenol A, 1,4-butanediol, ethylene glycol, piperazine, bisphenol S, bisphenol F, 4,4'-dihydroxybenzophenone, 4,4-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl sulfide.

[0015] The epoxy compound and the chain extender are fed according to the molar ratio of the epoxy group to the active hydrogen group of the chain extender, and the molar ratio of the epoxy group to the active hydrogen group is 1:(0.95-1.05).

[0016] The NMP accounts for 15-25 wt% of the total mass of the reaction system.

[0017] The added amount of the catalyst is 0.08-0.2 wt% of the total mass of the epoxy compound.

[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: (1) The catalyst prepared by the present invention activates hydroxyl groups through the imidazole and acid anhydride structures, thereby improving the efficiency of the chain extension reaction and achieving controlled polymerization of phenoxy resin by neutralizing the alkalinity of imidazole. The catalyst is used to prepare high molecular weight phenoxy resin with excellent tensile strength.

[0019] (2) The present invention uses NMP as a solvent, whose strong polarity promotes the uniform reaction of the epoxy resin and the chain extender; and the particles are pelletized and ground with liquid nitrogen to ensure uniform particle size; the solvent is evaporated by high-pressure and high-temperature nitrogen purge, avoiding the high residual rate of traditional vacuum distillation, and the solvent recovery rate is ≥95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a high-resolution mass spectrum of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0022] Example 1 Preparation of catalyst S1: In an ice bath, 1000 ml of methanol and 2 mol of N-vinylimidazole were added to a reaction kettle and stirred to mix. Under nitrogen, 500 ml of a methanol solution containing 1 mol of 4-(2-aminoethoxy)phenol was added dropwise over 2 h. The mixture was heated to room temperature and reacted for 10 h. The mixture was then distilled under reduced pressure at 50°C for 1 h to obtain 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol; its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d) δ 7.84 (tt, J = 1.7, 0.9 Hz, 2H), 7.38(s, 1H), 7.19 (ddt, J = 3.5, 1.7, 0.8 Hz, 2H), 7.07 (dd, J = 3.8, 1.7 Hz,2H), 6.89 - 6.76 (m, 4H), 4.10 (t, J = 5.9 Hz, 2H), 4.01 (tt, J = 4.2, 0.9Hz, 4H), 3.06 (t, J = 5.9 Hz, 2H), 2.84 (t, J = 4.2 Hz, 4H); S2: Under nitrogen protection, 800 ml of anhydrous THF, 0.6 mol of potassium carbonate, and 0.5 mol of 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol were added to a reaction kettle, stirred for 30 min, cooled to 0°C, and 400 ml of a tetrahydrofuran solution containing 0.5 mol of 4-chlorophthalic anhydride was added dropwise. The mixture was added dropwise for 1 h, and the temperature was raised to room temperature for 5 h. The mixture was filtered, and 1200 ml of n-hexane was added to the filtrate and stirred to precipitate a solid. The solid was filtered and dried in vacuo at 50°C for 8 h to obtain a diimidazolephthalic anhydride compound; its H NMR spectrum data are as follows: 1 H NMR (300 MHz, Chloroform- d ) δ 8.12 (d, J = 8.1 Hz, 1H), 7.84 (tt, J = 1.7, 0.9Hz, 2H), 7.69 (d, J = 2.7 Hz, 1H), 7.41 (dd, J = 8.0, 2.7 Hz, 1H), 7.23 -7.15 (m, 2H), 7.07 (dd, J = 3.8, 1.7 Hz, 2H), 6.97 - 6.80 (m, 4H), 4.10 (t, J= 5.9 Hz, 2H), 4.01 (tt, J = 4.2, 0.9 Hz, 4H), 3.06 (t, J = 5.9 Hz, 2H), 2.84(t, J = 4.2 Hz, 4H); S3: 1500 ml of anhydrous THF and 0.5 mol of diimidazole phthalic anhydride compound were added to a reaction kettle, stirred and mixed, and 145.8 g of boron trifluoride-ether solution (containing 1 mol of boron trifluoride) was added dropwise for 30 min. The mixture was reacted at room temperature for 4 h. The solid was filtered and washed twice with anhydrous THF (500 ml each time). The catalyst was dried under vacuum at 60°C for 6 h. Its H NMR spectrum data are as follows: 1 HNMR (300 MHz, Chloroform-d ) δ 9.71 (th, J = 1.7, 0.9 Hz, 2H), 8.12 (d, J =8.1 Hz, 1H), 7.78 (dp, J = 5.1, 1.7 Hz, 2H), 7.69 (d, J = 2.7 Hz, 1H), 7.58(ddt, J = 4.6, 3.06 (t, J= 5.9 Hz, 2H), 2.83 (t, J = 4.2 Hz, 4H); HRMS(m / z): 623.1982.

[0023] Example 2 Preparation of catalyst S1: In an ice bath, 1000 ml of methanol and 2.4 mol of N-vinylimidazole were added to a reaction kettle and stirred to mix. Under nitrogen protection, 500 ml of a methanol solution containing 1 mol of 4-(2-aminoethoxy)phenol was added dropwise over 2 h. The mixture was heated to room temperature and reacted for 12 h. The mixture was then distilled under reduced pressure at 50°C for 1 h to obtain 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol; S2: Under nitrogen protection, 800 ml of anhydrous THF, 0.6 mol of potassium carbonate, and 0.5 mol of 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol were added to a reaction kettle, stirred for 30 min, cooled to 0°C, and 400 ml of a tetrahydrofuran solution containing 0.55 mol of 4-chlorophthalic anhydride was added dropwise. The mixture was added dropwise for 1 h, and the reaction was heated to room temperature for 6 h. The mixture was filtered, and 1200 ml of n-hexane was added to the filtrate and stirred to precipitate a solid. The solid was filtered and dried in vacuo at 50°C for 8 h to obtain a diimidazolephthalic anhydride compound. S3: Add 1500 ml of anhydrous THF and 0.5 mol of diimidazole phthalic anhydride compound to a reaction kettle, stir to mix, and add 160.4 g of boron trifluoride-ether solution (containing 1.1 mol of boron trifluoride) dropwise for 30 minutes. React at room temperature for 5 hours, filter to obtain a solid, wash twice with anhydrous THF (500 ml each time), and dry in vacuo at 60°C for 6 hours to obtain the catalyst.

[0024] Example 3 Preparation of catalyst S1: In an ice bath, 1000 ml of methanol and 2.5 mol of N-vinylimidazole were added to a reaction kettle and stirred to mix. Under nitrogen protection, 500 ml of a methanol solution containing 1 mol of 4-(2-aminoethoxy)phenol was added dropwise over 2 h. The mixture was heated to room temperature and reacted for 15 h. The mixture was distilled under reduced pressure at 50°C for 1 h to obtain 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol; S2: Under nitrogen protection, 800 ml of anhydrous THF, 0.6 mol of potassium carbonate, and 0.5 mol of 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol were added to a reaction kettle, stirred for 30 min, cooled to 0°C, and 400 ml of a tetrahydrofuran solution containing 0.6 mol of 4-chlorophthalic anhydride was added dropwise. The mixture was added dropwise for 1 h, and the reaction was heated to room temperature for 8 h. The mixture was filtered, and 1200 ml of n-hexane was added to the filtrate and stirred to precipitate a solid. The solid was filtered and dried in vacuo at 50°C for 8 h to obtain a diimidazolephthalic anhydride compound. S3: Add 1500 ml of anhydrous THF and 0.5 mol of diimidazole phthalic anhydride compound to a reaction kettle, stir to mix, and add 175 g of boron trifluoride-ether solution (containing 1.2 mol of boron trifluoride) dropwise for 30 minutes. React at room temperature for 6 hours, filter to obtain a solid, wash twice with anhydrous THF (500 ml each time), and dry in vacuo at 60°C for 6 hours to obtain the catalyst.

[0025] Example 4 Preparation of phenoxy resin (1) 1000 g of bisphenol A epoxy resin (E-51, epoxy value 0.51 eq / 100 g), 500 g of ethylene glycol diglycidyl ether, 1175 g of bisphenol A, and 472 g of NMP were added to a reactor and stirred. The temperature was raised to 140°C. Under nitrogen protection, 1.2 g of catalyst (prepared in Example 1) was added. The temperature was raised to 150°C and the reaction was carried out for 3 h to obtain a resin solution. (2) The resin solution is passed through a pelletizer to be cut into strands, and the pelletizing temperature is controlled at 50°C to obtain pellets with a diameter of 1 mm; (3) The particles were frozen in liquid nitrogen (-196°C) and then ground into powder using a pulverizer to control the particle size to 1000 mesh to obtain a powder; (4) The powder was sprayed into the bottom of the fluidized bed evaporator through high-pressure and high-temperature nitrogen (pressure 0.5 MPa, temperature 260°C) to form a fluidized boiling state. The material stayed in the fluidized bed evaporator for 10 minutes. The NMP solvent evaporated in the high-temperature nitrogen and was discharged from the top with the air flow. The NMP was condensed and recovered (NMP 453 g, recovery rate 96%). The high-temperature semi-molten viscous material (solvent residue <0.1%) collected at the lower end of the fluidized bed evaporator was directly fed into a twin-screw extruder (temperature 240°C, speed 300 rpm) for extrusion and then air-cooled and pelletized to obtain phenoxy resin particles.

[0026] Example 5 Preparation of phenoxy resin (1) 800 g of bisphenol F epoxy resin (KF-8110, epoxy value 0.625 eq / 100 g), 1200 g of polyethylene glycol diglycidyl ether (epoxy value 0.28 eq / 100 g), 377 g of 1,4-butanediol, and 594 g of NMP were added to a reactor and stirred. The temperature was raised to 120 ° C. Under nitrogen protection, 3 g of catalyst (prepared in Example 2) was added. The temperature was raised to 140 ° C. and the reaction was carried out for 4 hours to obtain a resin solution.

[0027] (2) The resin solution is passed through a pelletizer to be cut into strands, and the pelletizing temperature is controlled at 70°C to obtain pellets with a diameter of 2 mm; (3) The particles were frozen in liquid nitrogen (-196°C) and then ground into powder using a pulverizer to control the particle size to 2000 mesh to obtain a powder; (4) The powder was sprayed into the bottom of the fluidized bed evaporator through high-pressure and high-temperature nitrogen (pressure 0.8 MPa, temperature 260°C) to form a fluidized boiling state. The material stayed in the fluidized bed evaporator for 20 minutes. The NMP solvent evaporated in the high-temperature nitrogen and was discharged from the top with the air flow. The NMP was condensed and recovered (NMP 576 g, recovery rate 97%). The high-temperature semi-molten viscous material (solvent residue <0.1%) collected at the bottom of the fluidized bed evaporator was directly fed into a twin-screw extruder (temperature 260°C, speed 200 rpm) for extrusion and then air-cooled and pelletized to obtain phenoxy resin particles.

[0028] Example 6

[0029] (1) 800 g of bisphenol S epoxy resin (185S, epoxy value 0.54 eq / 100 g), 1000 g of bisphenol H epoxy resin (LB101, epoxy value 0.43 eq / 100 g), 500 g of bisphenol F, 388 g of 4,4'-dihydroxybenzophenone, and 672 g of NMP were added to a reactor and stirred. The temperature was raised to 120°C. Under nitrogen protection, 3.6 g of catalyst (prepared in Example 3) was added, and the temperature was raised to 130°C for reaction for 5 h to obtain a resin solution. (2) The resin solution is passed through a pelletizer for strand pelletizing, and the pelletizing temperature is controlled at 80°C to obtain pellets with a diameter of 3 mm; (3) The particles were frozen in liquid nitrogen (-196°C) and then ground into powder using a pulverizer to control the particle size to 3000 mesh to obtain a powder; (4) The powder was sprayed into the bottom of the fluidized bed evaporator through high-pressure and high-temperature nitrogen (pressure 1 MPa, temperature 260°C) to form a fluidized boiling state. The material stayed in the fluidized bed evaporator for 30 minutes. The NMP solvent evaporated in the high-temperature nitrogen and was discharged from the top with the air flow. The NMP was condensed and recovered (652 g NMP g, recovery rate 97%). The high-temperature semi-molten viscous material (solvent residue <0.1%) collected at the lower end of the fluidized bed evaporator was directly fed into a twin-screw extruder (temperature 280°C, speed 100 rpm) for extrusion and then air-cooled and pelletized to obtain phenoxy resin particles.

[0030] Example 7

[0031] (1) 800 g of bisphenol A epoxy resin (E-44, epoxy value 0.44 eq / 100 g), 500 g of polypropylene glycol diglycidyl ether (epoxy value 0.30 eq / 100 g), 500 g of 1,4-cyclohexanedimethanol diglycidyl ether, 505 g of 4,4-dihydroxydiphenyl ether, 430 g of 4,4'-dihydroxydiphenyl sulfide, and 684 g of NMP were added to a reactor and stirred. The temperature was raised to 120° C. Under nitrogen protection, 3.6 g of catalyst (prepared in Example 3) was added, and the temperature was raised to 140° C. for reaction for 4 h to obtain a resin solution. (2) The resin solution is passed through a pelletizer for strand pelletizing, and the pelletizing temperature is controlled at 80°C to obtain pellets with a diameter of 3 mm; (3) The particles were frozen in liquid nitrogen (-196°C) and then ground into powder using a pulverizer to control the particle size to 3000 mesh to obtain a powder; (4) The powder was sprayed into the bottom of the fluidized bed evaporator through high-pressure and high-temperature nitrogen (pressure 1 MPa, temperature 260°C) to form a fluidized boiling state. The material stayed in the fluidized bed evaporator for 30 minutes. The NMP solvent evaporated in the high-temperature nitrogen and was discharged from the top with the air flow. The NMP was condensed and recovered (NMP 670 g, recovery rate 98%). The high-temperature semi-molten viscous material (solvent residue <0.1%) collected at the bottom of the fluidized bed evaporator was directly fed into a twin-screw extruder (temperature 280°C, speed 100 rpm) for extrusion and then air-cooled and pelletized to obtain phenoxy resin particles.

[0032] Example 8 Preparation of Phenoxy Resin (1) 1500 g of bisphenol A epoxy resin (E-44, epoxy value 0.44 eq / 100 g), 1500 g of hexanediol diglycidyl ether, 466 g of ethylene glycol, 241 g of piperazine, and 1236 g of NMP were added to a reactor and stirred. The temperature was raised to 120° C. Under nitrogen protection, 6 g of catalyst (prepared in Example 3) was added, and the temperature was raised to 130° C. for 3 h to obtain a resin solution. (2) The resin solution is passed through a pelletizer for strand pelletizing, and the pelletizing temperature is controlled at 80°C to obtain pellets with a diameter of 3 mm; (3) The particles were frozen in liquid nitrogen (-196°C) and then ground into powder using a pulverizer to control the particle size to 3000 mesh to obtain a powder; (4) The powder was sprayed into the bottom of the fluidized bed evaporator through high-pressure and high-temperature nitrogen (pressure 1 MPa, temperature 260°C) to form a fluidized boiling state. The material stayed in the fluidized bed evaporator for 30 minutes. The NMP solvent evaporated in the high-temperature nitrogen and was discharged from the top with the air flow. The NMP was condensed and recovered (NMP 1211 g, recovery rate 98%). The high-temperature semi-molten viscous material (solvent residue <0.1%) collected at the lower end of the fluidized bed evaporator was directly fed into a twin-screw extruder (temperature 280°C, speed 100 rpm) for extrusion and then air-cooled and pelletized to obtain phenoxy resin particles.

[0033] Example 9 Preparation of Phenoxy Resin The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 8, except that the reaction time of step (1) is 4 h.

[0034] Example 10 Preparation of phenoxy resin The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 8, except that the reaction time of step (1) is 5 h.

[0035] Comparative Example 1 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of catalyst prepared by the following method: The preparation process of the catalyst is basically the same as that of Example 3, except that the 4-chlorophthalic anhydride in step S2 is replaced by an equimolar amount of 3-(4-chlorophenyl)glutaric anhydride.

[0036] Comparative Example 2 The raw material composition and preparation method of phenoxy resin are basically the same as those in Comparative Example 1, except that the reaction time of step (1) is 5 h.

[0037] Comparative Example 3 Preparation of Phenoxy Resin The raw material composition and preparation method of the phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of a diimidazole phthalic anhydride compound (prepared in step S2 of Example 3).

[0038] Comparative Example 4 The raw material composition and preparation method of phenoxy resin are basically the same as those in Comparative Example 3, except that the reaction time of step (1) is 5 h.

[0039] Comparative Example 5 The raw material composition and preparation method of the phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of n-butyltriphenylphosphonium bromide.

[0040] Comparative Example 6 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of tetramethylammonium chloride.

[0041] Comparative Example 7 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of 2-methylimidazole.

[0042] Comparative Example 8 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of n-butyltriphenylphosphonium bromide, and the reaction time is 8 h.

[0043] Comparative Example 9 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of tetramethylammonium chloride and the reaction time is 8 h.

[0044] Comparative Example 10 The raw material composition and preparation method of phenoxy resin are basically the same as those in Example 9, except that the catalyst in step (1) is replaced by an equal weight of 2-methylimidazole, and the reaction time is 8 h.

[0045] The concentration of the boron trifluoride-diethyl ether solution used in this application is 46.5 wt %.

[0046] The phenoxy resins prepared in Examples 4-10 and Comparative Examples 1-7 were subjected to tensile strength tests according to the 5B dumbbell test required by GB / T 1040.1-2006. All specimens were uniaxially stretched at room temperature at a stretching rate of 5 mm / min. The test results are shown in Table 1.

[0047] Table 1 Performance data table

[0048] It can be seen from the data of Examples 4-10 that the phenoxy resin prepared in the present invention has a high molecular weight and excellent tensile strength, has important application value, and can achieve controllable polymerization of the phenoxy resin by changing the feed amount, reaction temperature, reaction time, etc.

[0049] The pyridinic nitrogen on the imidazole in the catalyst prepared by the present invention can first activate the anhydride group and the hydroxyl group to generate oxygen anions, which then undergo anionic polymerization with the epoxy group to simultaneously generate hydroxyl groups and oxygen anions. The oxygen anions then repeatedly undergo ring-opening reactions with the epoxy group to achieve chain growth, ultimately preparing a cured product. The nitrogen atom in the imidazole structure can donate electrons as a Lewis base, while BF3 as a Lewis acid can gain electrons. The lone pair of electrons on the nitrogen element can move to the boron element in the BF3 molecular structure, neutralizing the alkalinity of the imidazole to inhibit the reaction kinetic activity, establishing a time-dependent molecular weight control mechanism, and thus achieving controlled polymerization of the phenoxy resin molecular weight. The conjugated benzene ring system of the phthalic anhydride structure can stabilize the reaction intermediate state, reduce the reaction activation energy, and improve the reaction efficiency.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A process for preparing a high-performance phenoxy resin, characterized in that: The following steps are involved: (1) Add epoxy compound, chain extender and NMP into the reactor and stir, heat to 120-140℃, add catalyst under nitrogen protection, heat to 130-150℃, and react for 3-5h to obtain resin solution; (2) The resin solution is extruded through an extruder and then pelletized. The pelletizing temperature is controlled at 50-80°C to obtain pellets with a diameter of 1-3 mm. (3) After freezing the particles with liquid nitrogen, they are ground into powder using a pulverizer to control the particle size to 1000-3000 mesh to obtain a powder; (4) The powder is blown into a fluidized bed evaporator by high-pressure and high-temperature nitrogen gas, and NMP is evaporated and condensed for recovery. The high-temperature viscous material is collected, extruded through a twin-screw extruder, and then stretched and pelletized to obtain phenoxy resin particles; The catalyst is prepared by reacting N-vinylimidazole with 4-(2-aminoethoxy)phenol to generate 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol, which is then reacted with 4-chlorophthalic anhydride to generate a diimidazolephthalic anhydride compound, and finally reacted with a boron trifluoride-ether solution.

2. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The molar ratio of the N-vinylimidazole to 4-(2-aminoethoxy)phenol is (2-2.5):

1.

3. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The molar ratio of 4-(2-{bis[2-(1H-imidazol-1-yl)ethyl]amino}ethoxy)phenol to 4-chlorophthalic anhydride is 1:(1-1.2).

4. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The molar ratio of the diimidazole phthalic anhydride compound to the boron trifluoride-ether solution is 1:(2-2.4).

5. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The epoxy compound is an epoxy resin or a combination of an epoxy resin and glycidyl ether.

6. The process for preparing a high-performance phenoxy resin according to claim 5, characterized in that: The epoxy resin is a mixture of one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and bisphenol H epoxy resin; the glycidyl ether is a mixture of one or more of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, hexanediol diglycidyl ether, polypropylene glycol diglycidyl ether, and 1,4-cyclohexanedimethanol diglycidyl ether.

7. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The chain extender is a mixture of one or more of bisphenol A, 1,4-butanediol, ethylene glycol, piperazine, bisphenol S, bisphenol F, 4,4'-dihydroxybenzophenone, 4,4-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl sulfide.

8. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The epoxy compound and the chain extender are fed according to the molar ratio of the epoxy group to the active hydrogen group of the chain extender, and the molar ratio of the epoxy group to the active hydrogen group is 1:(0.95-1.05).

9. The process for preparing a high-performance phenoxy resin according to claim 1, wherein: The NMP accounts for 15-25 wt% of the total mass of the reaction system.

10. The process for preparing a high-performance phenoxy resin according to claim 1, characterized in that: The added amount of the catalyst is 0.08-0.2 wt% of the total mass of the epoxy compound.

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