A waterborne epoxy resin curing agent and its preparation method and application

Abstract

The present invention relates to a waterborne epoxy resin curing agent and a preparation method and application thereof. The waterborne epoxy resin curing agent is prepared from the following raw materials: a) hydrophobic amine and its derivatives; b) epoxy group-containing compounds; c) epoxy group-containing polyether compounds; d) polyether and epoxy resin grafted compounds. The waterborne epoxy resin curing agent has a good acid resistance effect and can be applied to the fields of waterborne floor and waterborne steel structure anticorrosive coatings, and has obvious application value.

Description

Technical Field

[0001] The invention belongs to the field of polymer chemistry, and specifically relates to a water-based epoxy resin curing agent and a preparation method and application thereof. Background Art

[0002] In recent years, driven by national policies and people's increasing awareness of environmental protection, the pace of epoxy resin coatings changing from "oil" to "water" has been accelerating, and the application of water-based epoxy resin coatings has become more and more extensive, with more and more types. However, the difference in performance between water-based epoxy coatings and oil-based epoxy coatings limits the application of water-based epoxy coatings in many aspects. The reason is that most of the current water-based epoxy curing agents are made of hydrophilic fatty amines. Because of the hydrophilic characteristics, fatty amines are easier to prepare water-based curing agents. However, the overly hydrophilic characteristics of fatty amines often lead to slower water volatilization during the curing process, which in turn leads to a decrease in the water resistance and corrosion resistance of water-based coatings.

[0003] In this case, we propose to introduce hydrophobic polyamines into water-based curing agents to replace the original hydrophilic polyamines to prepare water-based curing agents, thereby reducing the hydrophilic segments in the system, which can enhance the mechanical properties and water resistance of water-based epoxy coatings and expand the application areas of water-based epoxy coatings.

[0004] At present, there is no relevant patent or literature recording the method of using hydrophobic amine to prepare water-based curing agent. Therefore, it is of great significance to study the use of hydrophobic amine to prepare water-based epoxy resin curing agent. Summary of the invention

[0005] The purpose of the present invention is to provide a waterborne epoxy resin curing agent and a preparation method thereof. The waterborne epoxy resin curing agent is mainly prepared with hydrophobic amines, and the hydrophilic segments of the curing agent components are reduced to reduce the hydrophilic properties.

[0006] The waterborne epoxy resin curing agent of the present invention can be used to prepare waterborne coatings. The obtained waterborne coatings fully rely on the cross-linking of hydrophobic amines and epoxy resins to improve the water resistance, acid and alkali resistance and salt spray corrosion resistance of the waterborne coatings.

[0007] In order to achieve the above invention object, the present invention is implemented by the following technical solutions:

[0008] In a first aspect, the present invention provides a waterborne epoxy resin curing agent, which is prepared from the following raw materials:

[0009] a) Hydrophobic amines and their derivatives;

[0010] b) Compounds containing epoxy groups;

[0011] c) polyether compounds containing epoxy groups;

[0012] d) Polyether and epoxy resin grafted compounds.

[0013] In the present invention, the molar ratio of component a) to component b) is 1: (0.1-1), preferably 1: (0.2-0.7); the molar ratio of component a) to component c) is 1: (0.1-1), preferably 1: (0.2-0.7); the mass ratio of component d) to the sum of component a), component b) and component c) is 1: (2-9), preferably 1: (3-5).

[0014] In the present invention, the component a) is selected from one or more of diaminodicyclohexylmethane, tricyclic derivatives of diaminodicyclohexylmethane (such as Wanamine 2300 of Wanhua Chemical Polyurethane Co., Ltd.), dimethyldiaminodicyclohexylmethane and polycyclic derivatives of diaminodicyclohexylmethane (such as Wanamine 2400 of Wanhua Chemical Polyurethane Co., Ltd.), and secondary amine derivatives of diaminodicyclohexylmethane.

[0015] In the present invention, the component b) is selected from one or more combinations of epoxy resin E51, epoxy resin E44, epoxy resin E20, benzyl glycidyl ether, phenyl glycidyl ether, C12-C14 glycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, and 1,2-ethylene glycol diglycidyl ether; preferably epoxy resin E51.

[0016] In the present invention, the component c) is at least one selected from polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether.

[0017] In the present invention, the component d) is selected from polyethylene glycol with a weight average molecular weight of 1000 to 10000 or polypropylene glycol with a weight average molecular weight of 1000 to 10000 and an epoxy resin with a weight average molecular weight of 300 to 1000, and is synthesized in a molar ratio of 1:0.8 to 2.5 at 70 to 100° C. for 1 to 4 hours under the catalysis of a catalyst, preferably boron trifluoride etherate, aluminum trichloride, etc. (the amount of the catalyst is 5‰ to 2% of the mass of the reactants).

[0018] According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned waterborne epoxy resin curing agent, the method comprising reacting the following raw materials to prepare the above-mentioned waterborne epoxy resin curing agent:

[0019] a) hydrophobic amines and their derivatives;

[0020] b) Compounds containing epoxy groups;

[0021] c) polyether compounds containing epoxy groups;

[0022] d) polyether and epoxy resin grafted compounds;

[0023] Furthermore, the method for preparing the above-mentioned water-based epoxy resin curing agent comprises the following steps.

[0024] (1) adding selected masses of component a) and component b) into a reaction vessel, heating (e.g., heating to 70-100° C.) and stirring to react (e.g., reacting for 1-2 hours) to prepare an intermediate product;

[0025] (2) adding a selected mass of component c) to the reaction vessel, heating (e.g., reaction temperature of 70 to 100° C.) and stirring to react (e.g., react for 1 to 2 hours) to prepare an intermediate product;

[0026] (3) adding a selected mass of component d) into the reaction vessel, heating (e.g., reaction temperature is 70-100° C.) and stirring to react (e.g., react for 1-2 hours) to prepare a final product;

[0027] (4) Cooling the curing agent product to 50-70° C., adding deionized water at 50-70° C., and stirring and dispersing the mixture at 1000-3000 rpm to obtain a water-based epoxy resin curing agent.

[0028] Preferably, in the above preparation method, the component a) is selected from at least one of diaminodicyclohexylmethane, dimethyldiaminodicyclohexylmethane, tricyclic derivatives of diaminodicyclohexylmethane and modified derivatives of diaminodicyclohexylmethane, preferably diaminodicyclohexylmethane. The component b) is selected from at least one of epoxy resin E51, epoxy resin E44, epoxy resin E20, benzyl glycidyl ether, phenyl glycidyl ether, C12-C14 glycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,2-ethylene glycol diglycidyl ether and other glycidyl ethers, preferably epoxy resin E51. The component c) is selected from at least one of polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, preferably polyethylene glycol diglycidyl ether. The component d) is selected from polyethylene glycol with a weight average molecular weight of 1000 to 10000 or polypropylene glycol with a weight average molecular weight of 1000 to 10000 and epoxy resin with a weight average molecular weight of 300 to 1000, catalyzed by boron trifluoride etherate, aluminum trichloride, etc., in a molar ratio of 1:0.8 to 2.5, through a one-step synthesis or a multi-step synthesis through an intermediate, preferably a segmented polymer obtained by reacting polyethylene glycol with a molecular weight of 2000 with epoxy resin E20 under the catalysis of boron trifluoride etherate.

[0029] Preferably, in the above preparation method, the molar ratio of component a) to component b) is 1:(0.1-1), preferably 1:(0.2-0.7); the molar ratio of component a) to component c) is 1:(0.1-1), preferably 1:(0.2-0.7); the mass ratio of component d) to the sum of component a), component b) and component c) is 1:(2-9), preferably 1:(3-5).

[0030] In a third aspect, the present invention also provides the use of the above-mentioned water-based epoxy resin curing agent or the water-based epoxy resin curing agent prepared by the above-mentioned preparation method as a curing agent in the preparation of water-based coatings.

[0031] In a fourth aspect, the present invention provides a water-based coating, as shown in the following table, prepared using the above-mentioned water-based epoxy resin curing agent or the water-based epoxy resin curing agent prepared by the above-mentioned preparation method as a curing agent. In the early water resistance test of the water-based coating prepared by using the water-based epoxy resin curing agent prepared in the present invention according to the composition in the following table, the paint film did not show corrosion, and the salt spray resistance time could exceed 600h, meeting the actual use requirements.

[0032]

[0033] The dispersant may be BYK190, BYK180, TEGO-760w, the leveling wetting agent may be BYK-346, TEGO-4100, TEGO-270, the defoamer may be BYK019, TEGO-810, etc. The epoxy emulsion is a water-based epoxy emulsion prepared from a solid epoxy resin, such as wantipro0901 or wantipro0903 of Wanhua Chemical Group Co., Ltd., and WB6001 water-based epoxy emulsion of Dow Chemical, preferably wantipro0901.

[0034] Methods for preparing waterborne coatings from waterborne epoxy resin curing agents are well known in the art.

[0035] Preparation method of water-based paint: weigh a certain amount of deionized water, dispersant, leveling wetting agent and defoamer into a grinder, stir and disperse them evenly at 500-800rpm, and then weigh and add barium sulfate, titanium dioxide and zinc phosphate in turn and stir and mix them evenly. Then adjust the grinding speed to 2000-2500rpm. When the slurry fineness is below 40μm, reduce the speed to 500-800rpm. Then weigh and add epoxy emulsion and stir evenly to obtain component A of water-based paint. Then stir and mix component A and component B evenly according to the ratio to obtain water-based paint.

[0036] The technical solution of the present invention has the following advantages:

[0037] (1) The present invention creatively selects hydrophobic amines and their derivatives to replace hydrophilic amines, and prepares a water-based curing agent through a certain process. The water-based curing agent has fewer hydrophilic segments, and the entire system is closer to an oily system. When preparing water-based coatings, the water resistance and mechanical properties of the water-based paint film can be enhanced during the cross-linking process with epoxy resin. The water-based epoxy resin curing agent has a good acid resistance effect and can be applied to the fields of water-based flooring and water-based steel structure anti-corrosion coatings, and has obvious application value.

[0038] (2) The present invention can select different hydrophobic amines or hydrophobic amine derivatives, and can prepare water-based epoxy resin curing agents with different segment lengths, different systems, different mechanical strengths, and different properties by using epoxy group-containing compounds of different structures, thereby meeting various application requirements.

[0039] (3) The water-based epoxy resin curing agent of the present invention can be used alone or in combination with other epoxy resin curing agents, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0041] Figure 1 IR graph of the waterborne epoxy resin curing agent of Example 1 of the present invention;

[0042] Figure 2 IR graph of the waterborne epoxy resin curing agent of Example 2 of the present invention;

[0043] Figure 3 IR graph of the waterborne epoxy resin curing agent of Example 3 of the present invention;

[0044] Figure 4 This is the IR graph of the waterborne epoxy resin curing agent of Example 4 of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described by means of specific embodiments. The embodiments of the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0046] The names, abbreviations and sources of the main chemicals used in the examples of the present invention are shown in the following table. Unless otherwise specified, all reagents used were of chemical analytical grade.

[0047] Table 1

[0048]

[0049] Example 1

[0050] The preparation method of the water-based epoxy resin curing agent of this embodiment comprises the following steps: (1) adding 21 g (0.1 mol) of HMDA and 7.6 g (0.02 mol) of epoxy resin E51 into a three-necked reaction container, stirring evenly, heating to 80° C., and reacting for 2 h to obtain an intermediate product; (2) adding 8 g (0.02 mol) of polyethylene glycol diglycidyl ether into the three-necked reaction container in step (1), stirring at 80° C. and reacting for 2 h to obtain a curing agent product; (3) 7.3 g of the polyether and epoxy graft compound synthesized by reacting polyethylene glycol 1000 and epoxy resin E51 at a molar ratio of 1:1 under the catalysis of aluminum chloride (the amount of catalyst is 5‰ of the amount of the reactants) at 70°C for 4 hours was added to a three-necked reaction container, and reacted at 80°C for 2 hours to prepare a curing agent product; (4) the curing agent product was cooled to 50°C, 44 g of 50°C deionized water was added, and the mixture was stirred and dispersed uniformly at 1200 rpm to obtain a water-based epoxy resin curing agent. IR graph is shown in FIG. Figure 1 shown.

[0051] Example 2

[0052] The preparation method of the water-based epoxy resin curing agent of this embodiment comprises the following steps: (1) adding 23.8 g (0.1 mol) of 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and 16.4 g (0.1 mol) of benzyl glycidyl ether to a three-necked reaction container, stirring evenly, heating to 100° C., and reacting for 2 h to obtain an intermediate product; (2) adding 54 g (0.1 mol) of polypropylene glycol diglycidyl ether to the three-necked reaction container in step (1), stirring at 100° C. and reacting for 2 h to obtain a curing agent. (3) 31.4 g of polyethylene glycol 10000 and epoxy resin E20 were prepared in a molar ratio of 1:2.2 under the catalysis of boron trifluoride ether (the amount of catalyst was 5‰ of the mass of the reactants), and the synthesized polyether and epoxy grafted compound were added to a three-necked reaction vessel for 3 hours, and stirred at 100 ° C for 2 hours to prepare a curing agent product; (4) The above curing agent product was cooled to 55 ° C, 125.6 g of 55 ° C deionized water was added, and the mixture was stirred and dispersed evenly at 1200 rpm to obtain a water-based epoxy resin curing agent. IR graph is shown in the figure Figure 2 shown.

[0053] Example 3

[0054] The preparation method of the water-based epoxy resin curing agent of this embodiment comprises the following steps: (1) adding 38 g (0.1 mol) of Wanamine 2300 and 7.5 g (0.05 mol) of phenyl glycidyl ether to a three-necked reaction container, stirring evenly, heating to 70° C., and reacting for 2 h to obtain an intermediate product; (2) adding 20 g (0.05 mol) of polyethylene glycol diglycidyl ether to the three-necked reaction container in step (1), stirring at 70° C. and reacting for 2 h to obtain a curing agent product. ; (3) 16.3 g of polyether and epoxy grafted compound synthesized by reacting polypropylene glycol 5000 and epoxy resin E20 at a molar ratio of 1:1.5 under the catalysis of aluminum chloride (the amount of catalyst is 5‰ of the mass of the reactants) at 75°C for 4 hours were added to a three-necked reaction container, and reacted at 70°C for 2 hours to prepare a curing agent product; (4) The above curing agent product was cooled to 50°C, 82 g of 50°C deionized water was added, and stirred and dispersed evenly at 1200 rpm to obtain a water-based epoxy resin curing agent. IR graph is as follows Figure 3 shown.

[0055] Example 4

[0056] The preparation method of the water-based epoxy resin curing agent of this embodiment comprises the following steps: (1) adding 40 g (0.1 mol) of Wanamine 2400 and 19 g (0.05 mol) of epoxy resin E51 into a three-necked reaction container, stirring evenly, heating to 80° C., and reacting for 2 h to obtain an intermediate product; (2) adding 20 g (0.05 mol) of polyethylene glycol diglycidyl ether into the three-necked reaction container in step (1), stirring at 80° C. and reacting for 2 h to obtain a curing agent product. ; (3) 20g of the polyether and epoxy grafted compound synthesized by reacting polyethylene glycol 5000 and epoxy resin E20 in a molar ratio of 1:2 under the catalysis of aluminum chloride (the amount of catalyst is 5‰ of the mass of the reactants) at 80°C for 4h are added into a three-necked reaction container, and reacted at 80°C for 2h under stirring to prepare a curing agent product; (4) The above curing agent product is cooled to 50°C, 100g of 50°C deionized water is added, and stirred and dispersed evenly at 1200rpm to obtain a water-based epoxy resin curing agent. IR graph is as follows Figure 4 shown.

[0057] The waterborne epoxy resin curing agent prepared in Examples 1-4, the commercially available waterborne epoxy resin curing agent NX-8101 (Cardolite) and the component A prepared according to Table 2 and the following preparation method were mixed evenly in a certain ratio, and then the paint film sample was scraped and the acid resistance test was carried out. The test method was Method C in "GB / T9274-1988 Determination of Liquid Medium Resistance of Paints and Varnishes". The specific test results are shown in Table 3.

[0058] Table 2

[0059]

[0060]

[0061] The specific preparation method is: weigh deionized water, dispersant, leveling wetting agent and defoamer according to the mass in Table 2 into a grinder, stir and disperse them evenly at 600rpm, and then weigh barium sulfate, titanium dioxide and zinc phosphate according to Table 2 and stir and mix them evenly. Then adjust the grinding speed to 2200rpm, and when the slurry fineness is below 40μm, reduce the speed to 600rpm. Then weigh and add 42 parts of epoxy emulsion wanpro0901, stir evenly, and obtain component A of the water-based coating. Then weigh 20 parts of component B, stir and mix component A and component B evenly, and obtain the water-based coating.

[0062] Table 3

[0063] serial number Pencil hardness <![CDATA[Resistant to 10% H2SO4 (d)]]> Neutral salt spray resistance (d) Example 1 4H 2 25 Example 2 5H 2 20 Example 3 4H 2 25 Example 4 4H 2 17 Commercially available curing agent 2H 1 15

[0064] It can be seen from the test results in Table 3 that the epoxy resin cured paint films prepared by the water-based epoxy resin curing agents of Examples 1-4 of the present invention have good acid resistance, can meet the application requirements of epoxy resin floor materials, and have certain application fields.

[0065] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A water-based epoxy resin curing agent, characterized in that It is prepared from the following raw materials: a) hydrophobic amines and their derivatives; b) Compounds containing epoxy groups; c) polyether compounds containing epoxy groups; d) polyether and epoxy resin grafted compounds; Wherein, the component a) is selected from one or more of diaminodicyclohexylmethane, tricyclic derivatives of diaminodicyclohexylmethane, dimethyldiaminodicyclohexylmethane, polycyclic derivatives of diaminodicyclohexylmethane, and secondary amine derivatives of diaminodicyclohexylmethane; the component b) is selected from one or more of epoxy resin E51, epoxy resin E44, epoxy resin E20, benzyl glycidyl ether, phenyl glycidyl ether, C12-C14 glycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, and 1,2-ethylene glycol diglycidyl ether; the component c) is selected from at least one of polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; the molar ratio of the component d) polyether to the epoxy resin is 1:0.8-2.5; The preparation method of the water-based epoxy resin curing agent comprises: (1) adding selected mass of component a) and component b) into a reaction container, reacting under heating and stirring to prepare an intermediate product; adding selected mass of component c) into the reaction container, reacting under heating and stirring to prepare an intermediate product; (3) adding selected mass of component d) into the reaction container, reacting under heating and stirring to prepare a final product; (4) cooling the curing agent product to 50-70° C., adding deionized water of 50-70° C., and stirring and dispersing uniformly at 1000-3000 rpm to obtain a water-based epoxy resin curing agent, wherein the molar ratio of component a) to component b) is 1:(0.1-1), the molar ratio of component a) to component c) is 1:(0.1-1), and the mass ratio of component d) to the sum of component a), component b) and component c) is 1:(2-9).

2. The waterborne epoxy resin curing agent according to claim 1, characterized in that: The molar ratio of component a) to component b) is 1:(0.2-0.7); the molar ratio of component a) to component c) is 1:(0.2-0.7); the mass ratio of component d) to the sum of component a), component b) and component c) is 1:(3-5).

3. The waterborne epoxy resin curing agent according to claim 1, characterized in that: The component b) is selected from epoxy resin E51.

4. The waterborne epoxy resin curing agent according to any one of claims 1 to 3, characterized in that: The component d) is selected from polyethylene glycol with a weight average molecular weight of 1000-10000 or polypropylene glycol with a weight average molecular weight of 1000-10000 and epoxy resin with a weight average molecular weight of 300-1000 under the catalysis of a catalyst, in a molar ratio of 1:0.8-2.5, and is obtained by one step or multiple steps through intermediates.

5. The waterborne epoxy resin curing agent according to claim 4, characterized in that: The catalyst is boron trifluoride etherate or aluminum trichloride.

6. The method for preparing a waterborne epoxy resin curing agent according to any one of claims 1 to 5, characterized in that: The method includes: (1) adding component a) and component b) into a reaction vessel, heating to 70-100° C. and reacting for 1-2 hours under stirring to prepare an intermediate product; (2) adding component c) into the reaction vessel, heating to 70-100° C. and reacting for 1-2 hours under stirring to obtain an intermediate product; (3) adding component d) into the reaction vessel, heating to 70-100° C. and reacting for 1-2 hours under stirring to obtain a curing agent product; (4) Cooling the curing agent product to 50-70° C., adding deionized water at 50-70° C., and stirring and dispersing the mixture at 1000-3000 rpm to obtain a water-based epoxy resin curing agent.

7. Use of the waterborne epoxy resin curing agent according to any one of claims 1 to 5 or the waterborne epoxy resin curing agent prepared by the method described in claim 6 in the preparation of waterborne coatings.

8. A water-based paint, characterized in that: The waterborne epoxy resin curing agent according to any one of claims 1 to 5 or the waterborne epoxy resin curing agent prepared by the method according to any one of claims 6 to 7 is used as a curing agent for reaction and is prepared, and the formula is as follows: Component A contains 16-19 parts of water, 0.5-1 parts of dispersant, 8-16 parts of barium sulfate, 8-16 parts of titanium dioxide, 8-16 parts of zinc phosphate, 1-2 parts of leveling wetting agent, 1-2 parts of defoaming agent, and 40-45 parts of epoxy emulsion; Component B contains 15-25 parts of curing agent; wherein each component in A and B is calculated by mass.

9. The water-based paint according to claim 8, characterized in that: The epoxy emulsion is a water-based epoxy emulsion prepared from solid epoxy resin.

10. The water-based paint according to claim 9, characterized in that: The epoxy emulsion is wantipro0901 or wantipro0903 produced by Wanhua Chemical Group Co., Ltd. or WB6001 water-based epoxy emulsion produced by Dow Chemical.

11. The water-based paint according to claim 10, characterized in that: The epoxy emulsion is wantipro0901 produced by Wanhua Chemical Group Co., Ltd.

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