Amino polyarylether epoxy curing agent and method for preparing the same

Abstract

The application relates to an amino polyaromatic ether epoxy curing agent and a preparation method thereof, and belongs to the technical field of high polymer materials. The amino polyaromatic ether epoxy curing agent is prepared by the following steps: under the protection of high-purity nitrogen, reaction raw materials, a salting agent and a water-carrying agent are added into an organic solvent, the mixture is heated to reflux after being dissolved by being heated to remove the water-carrying agent, then the mixture is heated to react, a viscous solution is obtained after being cooled, the solution is discharged into ice water to obtain a white product, the product is crushed, then the crushed product is washed with distilled water and anhydrous ethanol under the protection of nitrogen, and the amino polyaromatic ether epoxy curing agent powder is obtained after being vacuum dried. Compared with a traditional curing agent, the amino polyaromatic ether epoxy curing agent has a larger molecular weight, the amino content of a molecular chain is controlled by adjusting a feeding ratio, the amine group density in the molecule is controlled, the crosslinking density after curing is controlled, the hardness, strength and durability of different materials are improved, and the service life is prolonged; according to the chemical structure of the curing agent and the curing conditions, a crosslinking network system with the properties of high toughness, chemical corrosion resistance, high strength and hardness, high bonding strength and high heat resistance can be obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to an amino polyarylether epoxy curing agent and a preparation method thereof. BACKGROUND

[0002] Epoxy resin is a kind of high polymer material with wide application and excellent performance. In order to meet different performance requirements in different application fields, the type, structure and performance of the epoxy resin curing agent are generally changed to achieve the purpose. In order to convert the epoxy resin into a hard and non-viscous thermosetting network, an epoxy resin curing agent must be used. Curing can be carried out through homopolymerization initiated by a catalytic curing agent or copolymerization with a multifunctional curing agent. However, the ordinary epoxy resin curing agent has poor temperature resistance and chemical resistance after curing, which greatly limits its application and promotion. In addition, due to the high crosslinking density of the epoxy resin, microcracks and holes may appear in the crosslinked network. Therefore, the research on the structure design, synthesis and application of the new epoxy resin curing agent undoubtedly has important practical significance.

[0003] The epoxy resin curing agent has a wide range of applications due to its various types, easy-to-obtain raw materials, simple curing process and good reaction safety, and mainly includes aliphatic amines and their derivatives, alicyclic polyamines and their derivatives, and aromatic polyamines and their derivatives. Among them, the basicity of aromatic amines is lower than that of aliphatic or alicyclic polyamines, and the reaction with epoxy resin is slow. Under normal circumstances, they have a long service life, and the best performance can be obtained through high-temperature curing in use, and are considered to be one of the curing agents with the most promising development. The amino polyarylether curing agent described in the application can maintain high mechanical properties and good thermal stability when operating at high temperatures, and the crosslinking density can also be adjusted by adjusting the amino content, which is conducive to improving the heat resistance and mechanical properties compared with the commercial small molecule aromatic curing agent. SUMMARY

[0004] The purpose of the application is to provide an amino polyarylether epoxy curing agent and a preparation method thereof, so that the molecular weight of the curing agent is larger than that of the traditional curing agent, the amino content of the molecular chain is controlled by adjusting the feeding ratio, and the crosslinking density after curing is adjusted by adjusting the amine group density in the molecule, so as to improve the hardness, strength and durability of different materials, thereby prolonging the service life (the performance data are shown in Table 2). According to the chemical structure of the curing agent and the curing conditions, a crosslinked network system with high toughness, chemical corrosion resistance, high strength and hardness, high adhesive strength, high heat resistance and the like can be obtained.

[0005] The preparation method of the amino polyarylether epoxy curing agent described in the application comprises the following steps:

[0006] (1) under the protection of high-purity nitrogen, the reaction raw materials and the salifying agent and the water-carrying agent are added into the organic solvent, and the temperature is raised to 70-90°C for stirring and dissolving for 1-3 hours, then heated to reflux and continue to stir for 3-6 hours, and the water-carrying agent is removed; then the temperature is raised to 160-200°C for reaction for 5-10 hours, and the temperature is lowered to 100-110°C to obtain a viscous solution, and the white product is obtained by discharging into ice water;

[0007] (2) the white product obtained in step (1) is crushed, then stirred and washed with distilled water and anhydrous ethanol at 80-100°C for 5-8 times under the protection of nitrogen, and the amino polyarylether epoxy curing agent powder of the present application is obtained after drying in a vacuum oven at 90-110°C, and the structural formula is as follows:

[0008]

[0009] M, N are positive integers, representing the number of polymerization units; M:N is determined according to the feeding ratio of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and dihydroxy aromatic monomer, and the molar ratio of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and dihydroxy aromatic monomer is 0.3-3:1, i.e. M:N=0.3-3:1.

[0010] Ar is

[0011]

[0012] one or more of the following:

[0013] The reaction raw materials used in step (1) are one of 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, 4,4-difluorobenzophenone monomer and 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane, dihydroxy aromatic monomer mixture;

[0014] The structural formula of 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, 4,4-difluorobenzophenone is shown as follows:

[0015]

[0016] The structural formula of dihydroxy aromatic monomer is shown as one of the following,

[0017]

[0018] The structural formula of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane is shown as follows:

[0019]

[0020] The organic solvent used in step (1) is one or more of acetone, sulfolane (TMS), N-methyl pyrrolidone (NMP) or N,N-dimethylacetamide (DMAC); the total solid content of the reaction raw materials in the solvent is 10-20% (mass percent);

[0021] The salt forming agent used in step (1) is anhydrous potassium carbonate (K2CO3).

[0022] The water-carrying agent used in step (1) is toluene.

[0023] The reflux temperature in step (1) is 130-150°C.

[0024] The molar ratio of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the molar amount of the dihydroxy aromatic monomer and the molar amount of 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone or 4,4-difluorobenzophenone monomer in step (1) is 0.9-1:1; the molar ratio of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the dihydroxy aromatic monomer is 0.3-3:1.

[0025] The molar ratio of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the salt forming agent is 1:1.1.

[0026] The volume ratio of the water-carrying agent to the solvent is 2:3. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 TGA curve of the amino polyarylether epoxy curing agent prepared in Example 1; it shows that the amino polyarylether prepared in Example 1 has good heat resistance;

[0028] Figure 2 NMR spectrum of the amino polyarylether epoxy curing agent prepared in Example 1. It shows that the amino polyarylether prepared in Example 1 is successfully synthesized;

[0029] Figure 3 Four DSC curves at different heating rates of the curing agent prepared in Example 1 mixed with epoxy resin and then cured;

[0030] The curing is carried out by uniformly mixing the epoxy resin and the amino polyarylether curing agent of the present application in a solvent, the solvent being one or more of N-methylpyrrolidone, N,N-dimethylacetamide, ethanol, and acetone; the amount of the amino polyarylether curing agent being 30-40 wt% of the total amount of the amino polyarylether curing agent and the epoxy resin, and the stirring speed being 500-1000 r / min, and the stirring time being 20-40 min. The four curves obtained have a heating rate of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min, respectively. As the heating rate increases, the exothermic peak temperature of each DSC curve increases accordingly. As the heating rate increases, the heat effect generated per unit time increases, and the temperature difference also increases, and the exothermic peak of the curing reaction moves in the direction of high temperature, and the curing reaction accelerates.

[0031] The exothermic peak starting position reaction temperature (Ti), the peak top temperature (Tp), and the termination temperature (Tf) move to the high temperature zone as the heating rate increases. In order to accurately determine the curing temperature of the curing agent, the Ti, Tf, and Tf at different rates are listed in Table 1.

[0032] Table 1: Temperature and heat flow curve (DSC) data of the amino polyarylether curing agent curing E12 resin at different heating rates

[0033]

[0034] The Ti, Tf, and Tf at different rates are subjected to linear regression to determine the optimal curing conditions of the system as 135℃, 146℃, and 157℃ for 2h each.

[0035] Figure 4 Electrochemical bode plots of the coatings cured by the curing agent of the present application and the E12 epoxy resin, and the curing agent of the present application and the E12 epoxy resin, respectively;

[0036] After the coating is immersed in 3.5% salt water for 30 days, the resistance value of the amino polyarylether epoxy curing system of the present application (solid line) at low frequency is about 10 11 , indicating that the coating still has good shielding effect and corrosion resistance; while the resistance value of the commercial small molecule curing agent system (dashed line) at low frequency decreases to about 10 8 , indicating that the salt water has entered the coating, but has not reached the substrate. The performance data of the coating are shown in Table 2, and it can be seen that the hardness and impact resistance of the coating cured by the amino polyarylether curing agent and the E12 epoxy resin are obviously higher than those of the coating cured by the DDS and the E12 epoxy resin.

[0037] The structural formula of the commercial small molecule curing agent used, diamino diphenyl sulfone (DDS), is shown below,

[0038]

[0039] Table 2: Coating performance data after curing of DDS with E12 epoxy resin and after curing of the amino polyarylether curing agent of the present application with E12 epoxy resin

[0040] adhesion hardness impact resistance (Kd-cm) thickness pm amino polyarylether + E12 0 grade 4H 50 55-60 DDS + E12 1 grade 3H 40 55-60

[0041] 1. The adhesion of the sample coating was tested according to GB / T 1720-1979 "Determination of adhesion of paint film".

[0042] 2. The thickness of the sample coating was tested according to GB / T 1764-1979 "Determination of thickness of paint film".

[0043] 3. The hardness of the sample coating was tested according to GB / T 6739-2006 "Determination of pencil hardness of paint film".

[0044] 4. The impact resistance of the sample coating was tested according to GB / T 20624.1-2006 "Determination of impact resistance of paint film". DETAILED DESCRIPTION

[0045] The specific embodiments of the present application will be described in detail below. It should be understood that the specific embodiments described herein are merely exemplary and illustrative of the present application and are not intended to limit the present application.

[0046] Therefore, the configuration of the embodiments described in the present specification is only the most preferred one of the embodiments of the present application, and does not represent all the technical ideas of the present application, and it should be understood that there can be various equivalents and modifications that can replace these embodiments at the time of filing the present application.

[0047] In the present specification, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, it should be understood that the terms "comprise", "have" or "include" are intended to specify the presence of the stated feature, number, step, constituent element or combination thereof, and do not preclude the presence or addition of one or more other features, numbers, steps, constituent elements or combinations thereof.

[0048] In the present specification, in the case where a quantity, concentration or other value or parameter is given as a range, a preferred range or a range of preferred upper and lower values, it should be understood that all ranges formed by any pair of an upper value or a preferred value as the upper limit and any lower value or a preferred value as the lower limit are specifically disclosed, whether the range is explicitly disclosed or not.

[0049] Where a range of values is recited in this specification, unless otherwise stated, the range is intended to include both endpoints and all integers and fractions within the range. The scope of the application is not intended to be limited to the specific values recited when defining the range.

[0050] Example 1

[0051] The present application provides an amino polyarylene ether epoxy curing agent and a preparation method thereof, which comprises the following steps:

[0052] (1) Under high-purity nitrogen atmosphere, 5.085 g of 4,4'-difluorodiphenyl sulfone, 5.1276 g of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane, 1.2133 g of 4,4'-dihydroxydiphenyl ether, and 3.0406 g of anhydrous potassium carbonate were added into a three-necked flask equipped with a mechanical stirring device, a thermometer, a water trap, a condenser tube, and a nitrogen protection device, 64 mL of N-methyl pyrrolidone (NMP) was used as a reaction solvent, the solid content of the reaction raw material was 15% (mass percentage), and 42 mL of toluene was added as a water-carrying agent.

[0053] (2) The temperature was raised to 80°C and stirred for 2 hours, then the temperature of the system was raised to 140°C and stirred for 4 hours, toluene was evaporated, the temperature was raised to 170°C and reacted for 6 hours, then the temperature was lowered to 100°C to obtain a viscous solution, and the product was discharged into ice water to obtain a white fibrous crude product.

[0054] (3) The obtained crude product was crushed by a pulverizer, then washed with distilled water and anhydrous ethanol at 90°C for 6 times under nitrogen protection, and dried in a vacuum oven at 100°C to obtain 8.25 g of an amino polyarylene ether epoxy curing agent powder, and the structural formula thereof is as shown below,

[0055]

[0056] In this example, M:N=7:3, and the amine equivalent (molecular mass of the curing agent / number of active hydrogen) is 190.

[0057] Example 2

[0058] (1) Under high-purity nitrogen atmosphere, 5.085 g of 4,4'-difluorodiphenyl sulfone, 5.1276 g of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane, 1.2133 g of 4,4'-dihydroxydiphenyl ether, and 3.0406 g of anhydrous potassium carbonate were added into a three-necked flask equipped with a mechanical stirring device, a thermometer, a water trap, a condenser tube, and a nitrogen protection device, 64 mL of N-methyl pyrrolidone (NMP) was used as a reaction solvent, the solid content of the reaction raw material was 15% (mass percentage), and 42 mL of toluene was added as a water-carrying agent.

[0059] (2) The temperature was raised to 80°C and stirred for 2 hours, the temperature of the system was raised to 130°C and refluxed for 4 hours, the toluene was evaporated, the temperature was raised to 170°C and reacted for 6 hours, then the temperature was lowered to 100°C to obtain a viscous solution, and the crude product was obtained in the form of white fibers in ice water.

[0060] (3) The obtained crude product was crushed by a pulverizer, and then washed with distilled water and anhydrous ethanol at 90°C for 6 times under nitrogen protection. After vacuum drying, the amino polyarylether epoxy curing agent powder was obtained, and its structural formula is shown below,

[0061]

[0062] In this embodiment, M:N = 7:3, and the amine equivalent (molecular weight of the curing agent / number of active hydrogen) is 190.

[0063] Example 3

[0064] (1) In a three-necked flask equipped with a mechanical stirring device, a thermometer, a water trap, a condenser tube, and a nitrogen protection device, 5.085 g of 4,4'-difluorodiphenyl sulfone, 5.1276 g of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane, 1.7658 g of 4,4'-(1,4-phenylene bis(oxy))diphenol, 3.0406 g of anhydrous potassium carbonate, 64 mL of N-methyl pyrrolidone (NMP) as a reaction solvent, and 42 mL of toluene as a water-carrying agent were added, and the solid content of the reaction raw materials was 18% (mass percentage).

[0065] (2) The temperature was raised to 80°C and stirred for 2 hours, the temperature of the system was raised to 130°C and refluxed for 4 hours, the toluene was evaporated, the temperature was raised to 170°C and reacted for 6 hours, then the temperature was lowered to 100°C to obtain a viscous solution, and the crude product was obtained in the form of white fibers in ice water.

[0066] (3) The obtained crude product was crushed by a pulverizer, and then washed with distilled water and anhydrous ethanol at 90°C for 6 times under nitrogen protection. After vacuum drying, the amino polyarylether epoxy curing agent powder was obtained, and its structural formula is shown below,

[0067]

[0068] In this embodiment, M:N = 7:3, and the amine equivalent (molecular weight of the curing agent / number of active hydrogen) is 190.

[0069] Example 4

[0070] (1) In a three-necked flask equipped with a mechanical stirrer, thermometer, water trap, condenser and nitrogen protection device, 5.085 g of 4,4'-difluorodiphenyl sulfone, 3.6626 g of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane, 2.0221 g of 4,4'-dihydroxy diphenyl ether and 3.0406 g of anhydrous potassium carbonate were added under a high-purity nitrogen atmosphere, 42 mL of N-methyl pyrrolidone (NMP) was used as the reaction solvent, the solid content of the reaction raw materials was 20% (mass percentage), and 28 mL of toluene was added as a water-carrying agent.

[0071] (2) The temperature was raised to 80°C and stirred for 2 hours, then the temperature of the system was raised to 150°C and stirred for 4 hours, the toluene was evaporated, the temperature was raised to 190°C and reacted for 8 hours, then the temperature was lowered to 100°C to obtain a viscous solution, and the crude product was obtained in the form of white fibers in ice water.

[0072] (3) The obtained crude product was crushed by a pulverizer, then washed with distilled water and anhydrous ethanol at 90°C for 6 times under nitrogen protection, and then dried in a vacuum oven at 100°C to obtain 6.77 g of amino polyarylether epoxy curing agent powder, and its structural formula is as shown below,

[0073]

[0074] In this embodiment, M:N = 1:1, and the amine equivalent (molecular weight of the curing agent / number of active hydrogens) is 250.

Claims

1. An aminopolyarylether epoxy curing agent characterized by: The structural formula is shown as follows, M, N are positive integers, representing the number of polymerization units; and M: N = 0.3-3:1; Ar is one or more of the following:

2. The preparation method of the amino polyarylether epoxy curing agent according to claim 1, comprising the following steps: (1) under the protection of high-purity nitrogen, the reaction raw materials, a salifying agent and a water-carrying agent are added into an organic solvent, and then the mixture is stirred and dissolved at 70-90 DEG C for 1-3 hours, heated to reflux and continuously stirred for 3-6 hours, and then the water-carrying agent is removed; then the mixture is heated to 160-200 DEG C for 5-10 hours, cooled to 100-110 DEG C to obtain a viscous solution, and then the solution is discharged into ice water to obtain a white product; the molar ratio of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane to the dihydroxy aromatic monomer and to 4, 4'-difluorodiphenyl sulfone or 4, 4'-dichlorodiphenyl sulfone is 0.9-1:1; the molar ratio of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane to the dihydroxy aromatic monomer is 0.3-3:1; the molar ratio of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane to the salifying agent is 1:1.1, and the volume ratio of the water-carrying agent to the solvent is 2:3; (2) the white product obtained in step (1) is crushed, and then the crushed product is stirred and washed with distilled water and anhydrous ethanol at 80-100 DEG C under the protection of nitrogen for 5-8 times, respectively, and then dried under vacuum at 90-110 DEG C to obtain an amino polyarylether epoxy curing agent powder; The reaction raw materials used in step (1) are a mixture of one of 4, 4'-difluorodiphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone, 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and a dihydroxy aromatic monomer; The structural formula of 4, 4'-difluorodiphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone is shown as follows, The structural formula of the dihydroxy aromatic monomer is shown as one of the following, 3. The preparation method of the amino polyarylene ether epoxy curing agent as described in claim 2, characterized in that: The organic solvent used in step (1) is one or more of acetone, sulfolane, N-methyl pyrrolidone and N, N-dimethylacetamide, and the total solid content of the reaction raw materials in the solvent is 10-20% by mass.

4. The preparation method of the amino polyarylene ether epoxy curing agent as described in claim 2, characterized in that: The salifying agent used in step (1) is anhydrous potassium carbonate.

5. The preparation method of the amino polyarylene ether epoxy curing agent as described in claim 2, characterized in that: The water-carrying agent used in step (1) is toluene.

6. The preparation method of the amino polyarylene ether epoxy curing agent according to claim 2, characterized in that: The reflux temperature in step (1) is 130-150 DEG C.

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