Aliphatic amine waterborne epoxy curing agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of chemical coatings, and provides an aliphatic amine waterborne epoxy curing agent as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing aliphatic amine and bisphenol A epoxy resin for addition reaction to obtain a first reaction solution; carrying out reduced pressure distillation on the first reaction liquid to remove fatty amine which does not participate in the reaction, so as to obtain a second reaction liquid; mixing the second reaction liquid with polyether alcohol diglycidyl ether, and carrying out chain extension reaction to obtain a third reaction liquid; and mixing the third reaction liquid with a monoepoxy compound to carry out an end capping reaction, and mixing with water after the end capping reaction is completed to obtain the aliphatic amine waterborne epoxy curing agent. According to the method, the length of a molecular chain can be more effectively controlled, the influence of free amine in a system on various properties is eliminated, the water resistance, corrosion resistance, compression resistance and fracture resistance of the aliphatic amine waterborne epoxy curing agent are improved, the application range is wider, and the application requirements in the fields of heavy corrosion prevention and building materials can be met.

Description

Technical Field

[0001] The invention relates to the technical field of chemical coatings, and in particular to a fatty amine waterborne epoxy curing agent and a preparation method and application thereof. Background Art

[0002] As people's environmental awareness increases, the call for environmental protection is growing. Especially in recent years, the international requirements for VOC emissions have become increasingly stringent, and the development direction of modern coatings has gradually tended to be low-pollution and pollution-free. Water-based coating systems have significantly reduced the volatility of solvents during the construction process. Compared with traditional solvent-based coatings, water-based coating systems are not only lower in cost but also more environmentally friendly. They have become the main trend of future coating development.

[0003] As early as the 1960s, waterborne epoxy coatings were widely used in the construction field and industrial light corrosion protection field. After entering the 21st century, waterborne epoxy coatings have gradually developed towards heavy corrosion protection and are widely used in the fields of containers, ships and cement mortar. However, waterborne epoxy coatings still have defects in anti-rust ability, metal adhesion ability, and flexural and compressive strength in mortar. The most important reason affecting these properties is the matching problem of waterborne epoxy resin and waterborne epoxy curing agent. Therefore, it is urgent to develop a waterborne epoxy curing agent that can meet the application needs of heavy corrosion protection and building materials.

[0004] There are many types of waterborne epoxy curing agents, and the synthesis routes are different. Among them, the modified polyamine synthesis method is often achieved by addition or chain extension of epoxy resin. However, the waterborne epoxy curing agents obtained by different synthesis process routes have significant differences in performance, especially in terms of anti-corrosion effect and application performance in cement mortar. Products prepared by existing methods often cannot meet high standards.

[0005] Therefore, it is of great significance to develop a water-based epoxy curing agent with strong water resistance, high corrosion resistance, and high compressive and flexural strength. Summary of the invention

[0006] In view of this, the present invention provides a fatty amine waterborne epoxy curing agent and a preparation method and application thereof, so as to solve the problems that the waterborne epoxy curing agent prepared by the existing method has low water resistance, poor corrosion resistance and low compressive and flexural strength.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides a method for preparing a fatty amine waterborne epoxy curing agent, comprising the following steps:

[0009] 1) mixing a fatty amine and a bisphenol A epoxy resin for addition reaction to obtain a first reaction solution;

[0010] 2) performing reduced pressure distillation on the first reaction liquid in step 1) to remove the fatty amine that has not participated in the reaction, to obtain a second reaction liquid;

[0011] 3) mixing the second reaction liquid with polyether alcohol diglycidyl ether to carry out a chain extension reaction to obtain a third reaction liquid;

[0012] 4) The third reaction liquid is mixed with a monoepoxy compound to perform an end-capping reaction, and after the end-capping reaction is completed, the mixture is mixed with water to obtain a fatty amine water-based epoxy curing agent.

[0013] Preferably, in step 1), the molar ratio of the fatty amine to the bisphenol A epoxy resin is 6 to 10:1; the fatty amine includes one or more of ethylenediamine, diethylenetriamine and triethylenetetramine; the bisphenol A epoxy resin includes one or more of E51 bisphenol A epoxy resin, E44 bisphenol A epoxy resin and E20 bisphenol A epoxy resin.

[0014] Preferably, the temperature of the addition reaction in step 1) is 55-75° C. and the time is 3-5 hours.

[0015] Preferably, the temperature of the reduced pressure distillation in step 2) is 160-200° C., the vacuum degree is 40-100 Pa, and the time is 1.5-3.5 h.

[0016] Preferably, the molar ratio of the bisphenol A epoxy resin to the polyether alcohol diglycidyl ether in step 3) is 1:0.3-0.5; the polyether alcohol diglycidyl ether in step 3) includes one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and polyhexylene glycol diglycidyl ether.

[0017] Preferably, the temperature of the chain extension reaction in step 3) is 60-65° C. and the time is 3-5 h.

[0018] Preferably, the molar ratio of the bisphenol A epoxy resin and the polyether alcohol diglycidyl ether to the monoepoxy compound in step 4) is 0.9-1.5:1; the monoepoxy compound in step 4) includes one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether.

[0019] Preferably, the temperature of the end-capping reaction in step 4) is 65-70° C. and the time is 3-5 h.

[0020] The present invention also provides a fatty amine waterborne epoxy curing agent prepared by the preparation method of the fatty amine waterborne epoxy curing agent, wherein the solid content of the fatty amine waterborne epoxy curing agent is 50-60%.

[0021] The present invention also provides an application of the aliphatic amine waterborne epoxy curing agent in the field of heavy corrosion protection and in building materials.

[0022] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0023] The preparation method of the present invention can more effectively control the length of the molecular chain and eliminate the influence of free amine in the system on various properties by distilling off excess amine after the addition reaction of the fatty amine and the epoxy resin. Compared with the water-based epoxy curing agent prepared by the existing preparation process, the water-based epoxy curing agent prepared by the method of the present invention shows more excellent properties in terms of water resistance, corrosion resistance, and compressive and flexural strength, greatly improving the coating surface performance, weather resistance and physical and mechanical properties of the water-based epoxy resin, and has a wider range of applications, which can meet the application needs in the fields of heavy corrosion protection and building materials. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing a fatty amine waterborne epoxy curing agent, comprising the following steps:

[0025] 1) mixing a fatty amine and a bisphenol A epoxy resin for addition reaction to obtain a first reaction solution;

[0026] 2) performing reduced pressure distillation on the first reaction liquid in step 1) to remove the fatty amine that has not participated in the reaction, to obtain a second reaction liquid;

[0027] 3) mixing the second reaction liquid with polyether alcohol diglycidyl ether to carry out a chain extension reaction to obtain a third reaction liquid;

[0028] 4) The third reaction liquid is mixed with a monoepoxy compound to perform an end-capping reaction, and after the end-capping reaction is completed, the mixture is mixed with water to obtain a fatty amine water-based epoxy curing agent.

[0029] In the present invention, the molar ratio of the fatty amine to the bisphenol A epoxy resin in step 1) is 6 to 10:1, preferably 7 to 8:1; the fatty amine includes one or more of ethylenediamine, diethylenetriamine and triethylenetetramine; the bisphenol A epoxy resin includes one or more of E51 bisphenol A epoxy resin, E44 bisphenol A epoxy resin and E20 bisphenol A epoxy resin, preferably E51 bisphenol A epoxy resin and / or E20 bisphenol A epoxy resin.

[0030] In the present invention, the temperature of the addition reaction in step 1) is 55-75°C, preferably 60-70°C, more preferably 65°C; the time of the addition reaction is 3-5h, preferably 3.5-4.5h, more preferably 4h.

[0031] In the present invention, the mixing step in step 1) is preferably: firstly heating the fatty amine to the reaction temperature, then dropping the bisphenol A epoxy resin, and after the dropping is completed, keeping the temperature to carry out the addition reaction; the dropping time is preferably 1.2 to 2.8 hours, more preferably 1.5 to 2.5 hours, and more preferably 2 hours.

[0032] In the present invention, the temperature of the reduced pressure distillation in step 2) is 160-200°C, preferably 170-190°C, and more preferably 175-180°C; the vacuum degree of the reduced pressure distillation is 40-100 Pa, preferably 50-80 Pa, and more preferably 60-70 Pa; the time of the reduced pressure distillation is 1.5-3.5 h, preferably 2.0-3.0 h, and more preferably 2.5 h.

[0033] In the present invention, the reduced pressure distillation in step 2) can evaporate excess fatty amine, which can more effectively control the length of the molecular chain and eliminate the influence of free amine in the system on various properties.

[0034] In the present invention, the molar ratio of the bisphenol A type epoxy resin to the polyether alcohol diglycidyl ether in step 3) is 1:0.3-0.5, preferably 1:0.35-0.45; the polyether alcohol diglycidyl ether in step 3) includes one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and polyhexylene glycol diglycidyl ether, preferably polyethylene glycol diglycidyl ether and / or polypropylene glycol diglycidyl ether.

[0035] In the present invention, the temperature of the chain extension reaction in step 3) is 60-65° C., preferably 63° C.; the time of the chain extension reaction is 3-5 h, preferably 4 h.

[0036] In the present invention, the mixing step in step 3) is preferably: firstly cooling the second reaction liquid to the reaction temperature, then dropping polyether alcohol diglycidyl ether, and after the dropping is completed, keeping the temperature to carry out the chain extension reaction; the dropping time is preferably 1.2 to 2.8 hours, more preferably 1.5 to 2.5 hours, and more preferably 2 hours.

[0037] In the present invention, the molar ratio of the bisphenol A epoxy resin and the polyether alcohol diglycidyl ether to the monoepoxy compound in step 4) is 0.9-1.5:1, preferably 1.0-1.4:1, and more preferably 1.15-1.35:1; the monoepoxy compound in step 4) includes one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether, preferably phenyl glycidyl ether and / or benzyl glycidyl ether.

[0038] In the present invention, the temperature of the end-capping reaction in step 4) is 65-70° C., preferably 68° C.; the time of the end-capping reaction is 3-5 h, preferably 4 h.

[0039] In the present invention, the mixing step in step 4) is preferably: firstly heating the third reaction liquid to the reaction temperature, then dropping the monoepoxy compound, and after the dropping is completed, keeping the temperature to carry out the end-capping reaction; the dropping time is preferably 1.2 to 2.8 hours, more preferably 1.5 to 2.5 hours, and more preferably 2 hours.

[0040] The present invention also provides a fatty amine waterborne epoxy curing agent prepared by the preparation method of the above-mentioned fatty amine waterborne epoxy curing agent, wherein the solid content of the fatty amine waterborne epoxy curing agent is 50-60%, preferably 52-58%, and more preferably 55%.

[0041] The present invention also provides an application of the aliphatic amine waterborne epoxy curing agent in the field of heavy corrosion protection and in building materials.

[0042] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Example 1

[0044] Add 0.7 mol of triethylenetetramine to a 500 ml four-necked flask, heat it to 65°C, and after the temperature is constant, drop 0.1 mol of E51 bisphenol A epoxy resin to carry out addition reaction, control the dropping time for 2 hours, and keep the temperature for 4 hours after the dropping is completed to obtain the first reaction liquid; then heat it to 200°C and control the vacuum degree at 65 Pa, carry out reduced pressure distillation for 2.5 hours, evaporate the unreacted triethylenetetramine, and obtain 0.5 mol of triethylenetetramine and the second reaction liquid, remove the vacuum, and cool to 63°C and add 0.04 mol of polyethylene glycol diglycidyl ether to the second reaction liquid for chain extension reaction, control the dropping time for 2 hours, and keep warm for 3 hours after the dropping is completed to obtain a third reaction liquid; then increase the temperature, add 0.12 mol of benzyl glycidyl ether to the third reaction liquid at 68°C within 2 hours, and keep warm for 3 hours after the dropping is completed to carry out end-capping reaction; after the end-capping reaction is completed, add 95.6 g of water and stir thoroughly for 2 hours to obtain a fatty amine water-based epoxy curing agent with a solid content of 55%.

[0045] Example 2

[0046] Add 0.7 mol of triethylenetetramine to a 500 ml four-necked flask, heat it to 60°C, and after the temperature is constant, drop 0.1 mol of E51 bisphenol A epoxy resin to carry out addition reaction, control the drop time to 2h, and keep the temperature for 4h after the drop addition is completed to obtain the first reaction liquid; then heat it to 190°C and control the vacuum degree at 50pa, carry out reduced pressure distillation for 2.5h, evaporate the unreacted triethylenetetramine, and obtain 0.5 mol of triethylenetetramine and the second reaction liquid, remove the vacuum, and cool to 6 0℃ and add 0.045 mol of polyethylene glycol diglycidyl ether to the second reaction liquid for chain extension reaction, control the dropping time for 2h, and keep warm for chain extension reaction for 3h after the dropping is completed to obtain a third reaction liquid; then increase the temperature, add 0.11 mol of benzyl glycidyl ether to the third reaction liquid at 65℃ within 2h, and keep warm for end-capping reaction for 3h after the dropping is completed; after the end-capping reaction is completed, add 96.1g of water and stir thoroughly for 2h to obtain a fatty amine water-based epoxy curing agent with a solid content of 55%.

[0047] Example 3

[0048] Add 0.7 mol of diethylenetriamine to a 500 ml four-necked flask, heat it to 65 ° C, and after the temperature is constant, add 0.1 mol of E51 bisphenol A epoxy resin for addition reaction, control the dropwise addition time for 2 hours, and keep the temperature for addition reaction for 4 hours after the dropwise addition is completed to obtain the first reaction liquid; then heat it to 180 ° C and control the vacuum degree at 90 Pa, perform reduced pressure distillation for 2.3 hours, evaporate the unreacted diethylenetriamine, and obtain 0.5 mol of diethylenetriamine and the second reaction liquid, remove the vacuum, and cool down The temperature was raised to 65°C and 0.04 mol of polyethylene glycol diglycidyl ether was dripped into the second reaction liquid for chain extension reaction, the dripping time was controlled for 2 hours, and after the dripping was completed, the chain extension reaction was kept warm for 3 hours to obtain a third reaction liquid; the temperature was then raised, and 0.12 mol of benzyl glycidyl ether was dripped into the third reaction liquid at 70°C within 2 hours, and after the dripping was completed, the end-capping reaction was kept warm for 3 hours; after the end-capping reaction was completed, 88 g of water was dripped and the mixture was fully stirred for 2 hours to obtain a fatty amine water-based epoxy curing agent with a solid content of 55%.

[0049] Comparative Example 1

[0050] 0.33 mol of triethylenetetramine was added to a 500 ml four-necked flask, and the temperature was raised to 65° C. After the temperature was constant, 0.1 mol of E51 bisphenol A epoxy resin was added dropwise for addition reaction, and the addition time was controlled to 2 h. After the addition was completed, the addition reaction was carried out by keeping the temperature for 4 h to obtain a first reaction liquid; then 0.043 mol of polyethylene glycol diglycidyl ether was added dropwise to the first reaction liquid within 2 h for chain extension reaction, and the chain extension reaction was carried out by keeping the temperature for 3 h after the addition was completed; then the temperature was raised to 200° C. and the vacuum degree was controlled at 65 Pa, and reduced pressure distillation was carried out for 2.5 h to evaporate the unreacted triethylenetetramine, and then the vacuum was removed, the temperature was lowered to 68° C. and 0.174 mol of benzyl glycidyl ether was added dropwise within 2 h. After the addition was completed, the temperature was kept for end-capping reaction for 3 h; after the end-capping reaction was completed, 109.6 g of water was added dropwise, and the mixture was fully stirred for 2 h to obtain a fatty amine water-based epoxy curing agent with a solid content of 55%.

[0051] Comparative Example 2

[0052] 0.33 mol of diethylenetriamine was added to a 500 ml four-necked flask, and the temperature was raised to 60° C. After the temperature was constant, 0.1 mol of E51 bisphenol A epoxy resin was added dropwise for addition reaction, and the addition time was controlled to 2 hours. After the addition was completed, the addition reaction was carried out by keeping the temperature for 4 hours to obtain a first reaction liquid; then 0.043 mol of polyethylene glycol diglycidyl ether was added dropwise to the first reaction liquid within 2 hours for chain extension reaction, and the chain extension reaction was carried out by keeping the temperature for 3 hours after the addition was completed; then the temperature was raised to 190° C. and the vacuum degree was controlled at 50 Pa, and reduced pressure distillation was carried out for 2.3 hours to evaporate the unreacted diethylenetriamine, and then the vacuum was removed, the temperature was lowered to 65° C. and 0.174 mol of benzyl glycidyl ether was added dropwise within 2 hours, and the end-capping reaction was carried out by keeping the temperature for 3 hours after the addition was completed; after the end-capping reaction was completed, 101.5 g of water was added dropwise, and the mixture was fully stirred for 2 hours to obtain a fatty amine water-based epoxy curing agent with a solid content of 55%.

[0053] Application Example 1

[0054] The fatty amine waterborne epoxy curing agent obtained in the above Examples 1 to 3 and Comparative Examples 1 to 2 was applied to a waterborne epoxy primer, and the performance of the waterborne epoxy primer was tested in parallel comparative experiments, wherein the waterborne epoxy primer was mixed with component A and component B (the mass ratio of component A to component B was 3:1), the formula of component A was shown in Table 1, and component B was the fatty amine waterborne epoxy curing agent prepared by the present invention.

[0055] Table 1 Component A of waterborne epoxy primer

[0056] raw materials Content w / % Deionized water 13.4 Dispersant 6208 0.8 Defoamer BYK024 0.3 Titanium dioxide R706 13.5 Carbon Black MA-100 0.2 Zinc phosphate 5 Aluminum tripolyphosphate 5 Sericite 4 Precipitated barium sulfate 6 White Carbon Black 0.2 Bentonite 0.2 Waterborne epoxy emulsion 384 50 Substrate wetting agent TEGO4100 0.4 Rheological additive 299 0.2 Anti-flash rust additive 179 0.8

[0057] The fatty amine waterborne epoxy curing agents obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were respectively mixed with the A component formula in Table 1 to obtain five waterborne epoxy primers, and the performance of the five waterborne epoxy primers was tested, and the test results are shown in Table 2. Among them, the surface drying time and the actual drying time were tested according to the test standard of GB / T1728-1979; the adhesion was tested according to the test standard of GB / T9286-1998; the hardness was tested according to the test standard of GB / T 6739-2002; the water resistance was tested according to the test standard of GB / T1733-1993; the salt spray resistance was tested according to the test standard of GB / T 1771-2007; and the flexural and compressive strength were tested according to the test standard of GB / T 17671-2021.

[0058] Table 2 Performance test results of waterborne epoxy primer

[0059]

[0060] From the comparison in Table 2, it is found that compared with Comparative Examples 1 to 2, Examples 1 to 3 of the present invention adopt the method of first distilling off the excess amine after the addition reaction of aliphatic amine and E51 epoxy resin, which can more effectively control the length of the molecular chain and eliminate the influence of free amine in the system on various properties. The obtained aliphatic amine waterborne epoxy curing agent has a qualitative improvement in water resistance, corrosion resistance and 7-day compressive and flexural strength compared with Comparative Examples 1 to 2, showing more excellent properties. At the same time, the aliphatic amine waterborne epoxy curing agent obtained in Examples 1 to 3 of the present invention also has good effects in terms of adhesion, pencil hardness, surface drying time and actual drying time, and can meet the application requirements in the field of heavy corrosion protection and building materials.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a fatty amine waterborne epoxy curing agent, characterized in that: The steps include: 1) mixing a fatty amine and a bisphenol A epoxy resin for addition reaction to obtain a first reaction solution; 2) performing reduced pressure distillation on the first reaction liquid in step 1) to remove the fatty amine that has not participated in the reaction, to obtain a second reaction liquid; 3) mixing the second reaction liquid with polyether alcohol diglycidyl ether to carry out a chain extension reaction to obtain a third reaction liquid; 4) The third reaction liquid is mixed with a monoepoxy compound to perform an end-capping reaction, and after the end-capping reaction is completed, the mixture is mixed with water to obtain a fatty amine water-based epoxy curing agent.

2. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 1, characterized in that: The molar ratio of the fatty amine to the bisphenol A epoxy resin in step 1) is 6 to 10:1; The fatty amine includes one or more of ethylenediamine, diethylenetriamine and triethylenetetramine; The bisphenol A epoxy resin includes one or more of E51 bisphenol A epoxy resin, E44 bisphenol A epoxy resin and E20 bisphenol A epoxy resin.

3. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 2, characterized in that: The temperature of the addition reaction in step 1) is 55-75° C. and the time is 3-5 hours.

4. The method for preparing a fatty amine waterborne epoxy curing agent according to any one of claims 1 to 3, characterized in that: The temperature of the reduced pressure distillation in step 2) is 160-200° C., the vacuum degree is 40-100 Pa, and the time is 1.5-3.5 h.

5. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 4, characterized in that: The molar ratio of the bisphenol A epoxy resin to the polyether alcohol diglycidyl ether in step 3) is 1:0.3-0.5; The polyether alcohol diglycidyl ether in step 3) includes one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and polyhexylene glycol diglycidyl ether.

6. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 5, characterized in that: The temperature of the chain extension reaction in step 3) is 60-65° C. and the time is 3-5 hours.

7. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 6, characterized in that: The molar ratio of the bisphenol A epoxy resin and the polyether alcohol diglycidyl ether to the monoepoxy compound in step 4) is 0.9 to 1.5:1; The monoepoxy compound in step 4) includes one or more of C12-C14 alkyl glycidyl ether, n-butyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether and benzyl glycidyl ether.

8. The method for preparing a fatty amine waterborne epoxy curing agent according to claim 7, characterized in that: The temperature of the end-capping reaction in step 4) is 65-70° C. and the time is 3-5 hours.

9. The fatty amine waterborne epoxy curing agent prepared by the method for preparing a fatty amine waterborne epoxy curing agent according to any one of claims 1 to 8, characterized in that: The solid content of the fatty amine waterborne epoxy curing agent is 50-60%.

10. Use of the fatty amine waterborne epoxy curing agent according to claim 9 in the field of heavy corrosion protection and building materials.

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