Solvent-free waterborne epoxy film forming matter as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water-based paint, and particularly discloses a solvent-free water-based epoxy film forming matter and a preparation method and application thereof. Epoxy resin and bisphenol compounds are subjected to a catalytic reaction, and solvent-free epoxy resin is obtained; then mixing with a water-based epoxy emulsifier to react, and then carrying out water-phase inversion emulsification treatment to obtain the solvent-free water-based epoxy film forming matter. Compared with the current mainstream solvent-free water-based epoxy resin, the solvent-free water-based epoxy film forming material prepared by the invention does not need to add any epoxy reactive diluent and dimer acid modifier, so that the production cost is greatly saved, the market demand of pursuing low VOC emission at present is met, and the mechanical property and the corrosion resistance of the product are not reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based paint, in particular to a solvent-free water-based epoxy film former and its preparation method and application. BACKGROUND

[0002] Water-based epoxy paint uses water-based epoxy resin and curing agent as film former, and the coating has excellent medium resistance and environmental protection properties, and is widely used in the field of metal and concrete protection. In the preparation process of water-based epoxy resin, alcohol ether type cosolvent is often added to promote the dissolution of epoxy resin and improve the stability of the emulsion. However, these cosolvents will volatilize during paint application and drying, forming VOC (volatile organic compounds) which can harm the environment and workers. Therefore, the research and development of solvent-free water-based epoxy resin has positive practical significance.

[0003] Most of the solvent-free water-based epoxy resins on the market are emulsions of liquid epoxy resins, such as Chinese patent application CN118725255A discloses a self-emulsifying solvent-free water-based epoxy resin. However, the epoxy resins used in this application are all low molecular weight bisphenol A, bisphenol F and phenolic liquid epoxy resins. The application of this type of epoxy emulsion is mostly concentrated in the field of concrete protection, and its application in water-based epoxy anticorrosive paint is less.

[0004] Water-based epoxy anticorrosive paint is mostly used for the protection of metal substrates, and mainly uses emulsions of bisphenol A type solid epoxy resins with high molecular weight as the main film former. Because of the high viscosity of bisphenol A type solid epoxy resin, alcohol ether type solvent needs to be added to successfully prepare water-based epoxy resin. Existing research mainly replaces the solvent by adding epoxy active diluents in the system, such as Zhu Jiedong et al. (Zhu Jiedong, Yang Tingxiu, Zhang Tingting. Synthesis of zero VOC water-based epoxy emulsion and its paint film performance research [J]. Shanghai coatings, 2021, 59(06): 1-4.) by adding cashew phenol type active diluent, tertiary carbonic acid glycidyl ester, 1,6-hexanediol diglycidyl ether, and dimer acid diglycidyl ether, an epoxy emulsion with an epoxy equivalent weight of 500 was prepared by using external emulsification process. However, the results show that most of the active diluents will affect the salt spray resistance of the coating, and increase the cost of emulsion preparation.

[0005] Another way is to introduce dimer acid to react with bisphenol A epoxy resin, reduce the viscosity of the system to facilitate phase inversion emulsification. As Mu Di et al. (Mu Di, Yao Weiliang, He Shuqian, et al. Preparation of low VOC epoxy emulsion and its corrosion resistance research [J]. Coatings Industry, 2025, 55 (05): 46-52.) by introducing 12-14% dimer acid into the system, chain extension with E51 epoxy resin and bisphenol A, preparation of water-based epoxy resin containing a small amount of dioxane solvent. Research found that only the amount of dimer acid is 12-14%, the water-based epoxy resin with stable performance can be prepared. The modified formula has a narrow application range.

[0006] Therefore, the method of using active diluent and dimer acid instead of solvent to prepare solvent-free water-based epoxy resin has obvious shortcomings and limitations. SUMMARY

[0007] Therefore, the present application provides a solvent-free water-based epoxy film-forming material and its preparation method and application, which discards the scheme of using active diluent and dimer acid instead of solvent, improves the salt spray resistance of the final coating and the application range, and reduces the preparation cost.

[0008] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0009] A preparation method of a solvent-free water-based epoxy film-forming material, comprising the following steps:

[0010] 1) catalytic reaction of epoxy resin and bisphenol compound to obtain solvent-free epoxy resin;

[0011] 2) mixing and reacting the solvent-free epoxy resin with water-based epoxy emulsifier, and then performing water phase reverse emulsification treatment to obtain the solvent-free water-based epoxy film-forming material.

[0012] Preferably, the epoxy resin in step 1) includes bisphenol F type epoxy resin and / or tyrosine dipeptide based epoxy resin.

[0013] The bisphenol compound includes one or more of bisphenol F, tyrosine dipeptide and hydroquinone.

[0014] Preferably, the molar ratio of epoxy groups in the epoxy resin to phenolic hydroxyl groups in the bisphenol compound in step 1) is 2.2-2.45:1.

[0015] Preferably, the temperature of the catalytic reaction in step 1) is 100-130℃, and the time is 2-3h.

[0016] The catalyst for the catalytic reaction includes one or more of guanidine, quaternary ammonium salt, quaternary ammonium base compound, triphenylphosphine compound and its derivatives.

[0017] The amount of the catalyst in the catalytic reaction is 0.01-0.3% of the total mass of the epoxy resin and the bisphenol compound.

[0018] Preferably, the preparation method of the water-based epoxy emulsifier in step 2) comprises: carrying out a first reaction of polyethylene glycol diglycidyl ether and a difunctional polyether amine, adding a monofunctional polyether amine to carry out a second reaction after the first reaction, obtaining a modified polyether amine compound, and then carrying out a third reaction of the modified polyether amine compound and an epoxy resin to obtain the water-based epoxy emulsifier.

[0019] The molar ratio of the polyethylene glycol diglycidyl ether to the difunctional polyether amine is 2:1.

[0020] The amount ratio of the polyethylene glycol diglycidyl ether to the monofunctional polyether amine is 2:1.

[0021] The molar ratio of the polyethylene glycol diglycidyl ether to the epoxy resin is 1:4.

[0022] The temperature of the first reaction is 60-80℃, and the time of the first reaction is 2-4h.

[0023] The temperature of the second reaction is 100-120℃, and the time of the second reaction is 2-4h.

[0024] The temperature of the third reaction is 100-120℃, and the time of the third reaction is 2-4h.

[0025] Preferably, the mass ratio of the solvent-free epoxy resin to the water-based epoxy emulsifier in step 2) is 85-93:7-15.

[0026] Preferably, the temperature of the reaction in step 2) is 100-130℃, and the time is 10-30min.

[0027] Preferably, the aqueous phase reverse emulsification treatment in step 2) is to add water dropwise to the solution after the reaction of the solvent-free epoxy resin and the water-based epoxy emulsifier, and then carry out shearing treatment.

[0028] The mass ratio of the total mass of the solvent-free epoxy resin and the water-based epoxy emulsifier to the mass of water is 1.1-1.4:1, the temperature of the aqueous phase reverse emulsification treatment is 50-70℃, the dropwise adding speed of water is 2-5 drops / s, and the shearing speed is 2000-4000r / min.

[0029] Another object of the present application is to provide a solvent-free water-based epoxy film-forming material prepared by the preparation method.

[0030] Still another object of the present application is to provide an application of the solvent-free water-based epoxy film-forming material in a two-component water-based epoxy anticorrosive coating and an adhesive.

[0031] Via the technical solution, compared with the prior art, the present application has the following beneficial effects:

[0032] 1、The preparation process of the solvent-free waterborne epoxy resin does not add any solvent, which meets the current market demand for low VOC emission.

[0033] 2、The solvent-free waterborne epoxy resin prepared by the present application does not need to add any epoxy active diluent and dimer acid modifier compared with the current mainstream solvent-free waterborne epoxy resin, which greatly saves the production cost.

[0034] 3、The solvent-free waterborne epoxy resin prepared by the present application does not reduce the glass transition temperature, and does not reduce the mechanical properties and corrosion resistance while realizing solvent-free. DETAILED DESCRIPTION

[0035] The present application provides a preparation method of a solvent-free waterborne epoxy film-forming material, comprising the following steps:

[0036] 1) catalyzing the epoxy resin and the bisphenol compound to obtain a solvent-free epoxy resin;

[0037] 2) mixing the solvent-free epoxy resin and the waterborne epoxy emulsifier to react, and then performing water phase reverse emulsification treatment to obtain a solvent-free waterborne epoxy film-forming material.

[0038] In the present application, the epoxy resin in step 1) includes a bisphenol F type epoxy resin and / or a tyrosine dipeptide-based epoxy resin.

[0039] In the present application, the epoxy equivalent weight of the bisphenol F type epoxy resin is 160-180 g / eq, and specifically can be 162 g / eq, 165 g / eq, 168 g / eq, 170 g / eq, 172 g / eq, 175 g / eq, 178 g / eq; the epoxy equivalent weight of the tyrosine dipeptide-based epoxy resin is 140-160 g / eq, and specifically can be 142 g / eq, 145 g / eq, 148 g / eq, 150 g / eq, 152 g / eq, 155 g / eq, 158 g / eq.

[0040] In the present application, when the epoxy resin contains both the bisphenol F type epoxy resin and the tyrosine dipeptide-based epoxy resin, the molar ratio of the bisphenol F type epoxy resin to the tyrosine dipeptide-based epoxy resin is preferably 1-5:0-5 (not 0), further preferably 2-4:1-4, and still further preferably 3:2-3.

[0041] In the present application, the structure of the tyrosine dipeptide-based epoxy resin includes:

[0042]

[0043] In the present application, the bisphenol compound includes one or more of bisphenol F, tyrosine dipeptide and hydroquinone.

[0044] In the present application, the molar content of bisphenol F in the bisphenol compound is preferably ≥ 50%, and can be 50%, 55%, 60%, 65%, 70%, 75%, 80% in particular.

[0045] In the present application, the structure of the tyrosine dipeptide is:

[0046] In the present application, the molar ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the bisphenol compound in step 1) is 2.2-2.45:1, preferably 2.25-2.4:1, and further preferably 2.3-2.35:1.

[0047] In the present application, the temperature of the catalytic reaction in step 1) is 100-130℃, and can be 102℃, 105℃, 108℃, 110℃, 112℃, 115℃, 118℃, 120℃, 125℃, 128℃ in particular; the time is 2-3h, and can be 2.2h, 2.4h, 2.5h, 2.6h, 2.8h in particular.

[0048] In the present application, the catalyst of the catalytic reaction includes one or more of guanidine, quaternary ammonium salt, quaternary ammonium base compound, triphenylphosphine compound and its derivatives.

[0049] In the present application, the amount of catalyst used in the catalytic reaction is 0.01-0.3% of the sum of the mass of the epoxy resin and the bisphenol compound, and can be 0.02%, 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25% in particular.

[0050] In the present application, the prepared solvent-free epoxy resin has an epoxy equivalent weight of 375-750g / eq, 400g / eq, 450g / eq, 500g / eq, 550g / eq, 600g / eq, 650g / eq, 700g / eq, and is in a solid state at room temperature.

[0051] In the present application, the preparation method of the water-based epoxy emulsifier in step 2) includes: first reacting polyethylene glycol diglycidyl ether with a di-functional polyether amine, after the reaction is completed, adding a mono-functional polyether amine for a second reaction to obtain a modified polyether amine compound, and then performing a third reaction of the modified polyether amine compound with an epoxy resin to obtain a water-based epoxy emulsifier.

[0052] In the present application, the average molecular weight of the polyethylene glycol diglycidyl ether is 400-1000, and can be 500, 600, 700, 800, 900 in particular; the average molecular weight of the difunctional polyether amine is 600-3050, and can be 800, 1000, 1500, 2000, 2500, 3000 in particular; the difunctional polyether amine specifically includes commercially available product trade marks: ED-900, ED-1500, ED-2003, ED-3050; the average molecular weight of the monofunctional polyether amine is 600-2100, and can be 800, 1000, 1500, 2000 in particular; the monofunctional polyether amine specifically includes commercially available product trade marks: ZM-160, ZM-1100, ZM-1207, M1000, M2070.

[0053] In the present application, the average molecular weight of the modified polyether amine compound prepared is 3000-8000.

[0054] In the present application, the ratio of the polyethylene glycol diglycidyl ether to the difunctional polyether amine is 2:1; the ratio of the polyethylene glycol diglycidyl ether to the monofunctional polyether amine is 2:1; and the molar ratio of the polyethylene glycol diglycidyl ether to the epoxy resin is 1:4.

[0055] In the present application, the temperature of the first reaction is 60-80℃, and can be 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃ in particular; the time of the first reaction is 2-4h, and can be 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h, 3.8h in particular; the temperature of the second reaction is 100-120℃, and can be 102℃, 105℃, 108℃, 110℃, 112℃, 115℃, 118℃ in particular; the time of the second reaction is 2-4h, and can be 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h, 3.8h in particular; the temperature of the third reaction is 100-120℃, and can be 102℃, 105℃, 108℃, 110℃, 112℃, 115℃, 118℃ in particular; the time of the third reaction is 2-4h, and can be 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h, 3.8h in particular.

[0056] In the present application, the mass ratio of the solvent-free epoxy resin to the water-based epoxy emulsifier in step 2) is 85-93:7-15, preferably 86-92:8-14, and further preferably 88-90:10-12.

[0057] In the present application, the temperature of the reaction in step 2) is 100-130℃, and specifically can be 102℃, 105℃, 108℃, 110℃, 112℃, 115℃, 118℃, 120℃, 125℃, 128℃; the time is 10-30min, and specifically can be 12min, 15min, 18min, 20min, 22min, 25min, 28min.

[0058] In the present application, the water-phase reverse emulsification treatment in step 2) is to add water dropwise to the solution after the solvent-free epoxy resin and the water-based epoxy emulsifier are reacted, and then perform shearing treatment.

[0059] In the present application, the ratio of the sum of the mass of the solvent-free epoxy resin and the mass of the water-based epoxy emulsifier to the mass of water is 1.1-1.4:1, preferably 1.2-1.35:1, and further preferably 1.22:1; the temperature of the water-phase reverse emulsification treatment is 50-70℃, and specifically can be 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃; the dropwise adding rate of water is 2-5 drops / s, and specifically can be 2 drops / s, 3 drops / s, 4 drops / s, 5 drops / s; the shearing treatment rate is 2000-4000r / min, and specifically can be 2200r / min, 2500r / min, 2800r / min, 3000r / min, 3200r / min, 3500r / min, 3800r / min.

[0060] The present application also provides a solvent-free water-based epoxy film-forming material prepared by the above preparation method.

[0061] The present application also provides an application of the above solvent-free water-based epoxy film-forming material in a two-component water-based epoxy anticorrosive coating and an adhesive.

[0062] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0063] Embodiment 1

[0064] Example 1 187.79 g of epoxy resin NPEF-170 (Nanya Epoxy Resin Co., Ltd., molecular weight 340) and 48 g of bisphenol F (molecular weight 200.24) were added to a 250 ml reaction vessel equipped with a stirring device and a thermometer (molar ratio of epoxy groups of the epoxy resin to phenolic hydroxyl groups of the bisphenol compound was 2.3:1), and after complete dissolution into a solution by heating to 110°C, 0.59 g of triphenylphosphine (molecular weight 262.29) was added, and heating was performed to 115°C for 2 h to obtain a solvent-free epoxy resin (epoxy equivalent weight was 400 g / eq).

[0065] Example 2 100 g of polyethylene glycol diglycidyl ether (average molecular weight 500) and 300 g of polyether amine ED-3050 (average molecular weight 3000) were added to a 1 L reaction vessel equipped with a stirring device and a thermometer, and heating was performed to 80°C for 2 h, and then 100 g of monofunctional polyether amine M1000 (average molecular weight 1000) was added, and heating was performed to 120°C for 3 h, and then 302.4 g of epoxy resin E51 (molecular weight 378) was added, and heating was performed to 100°C for 3 h to obtain an aqueous epoxy emulsifier.

[0066] Example 3 30.65 g of the aqueous epoxy emulsifier was mixed with 236.61 g of the solvent-free epoxy resin prepared above, and shearing emulsification was performed at 120°C for 10 min by slowly adding 201.62 g of deionized water at a rate of 2 drops / s (temperature was 65°C, and shearing rate was 3000 r / min) to obtain a solvent-free aqueous epoxy film former, which had a solid content of 57%, an average particle size of 320 nm, a fineness of 20 μm, and a milky white blue light-emitting emulsion.

[0067] Example 2

[0068] Example 4 187.79 g of epoxy resin NPEF-170 (Nanya Epoxy Resin Co., Ltd., molecular weight 340) and 35 g of tyrosine dipeptide (molecular weight 326) and 24 g of bisphenol F were added to a 300 ml reaction vessel equipped with a stirring device and a thermometer (molar ratio of epoxy groups of the epoxy resin to phenolic hydroxyl groups of the bisphenol compound was 2.43:1), and after complete dissolution into a solution by heating to 110°C, 0.62 g of triphenylphosphine (molecular weight 135.21) was added, and heating was performed to 130°C for 2 h to obtain a solvent-free epoxy resin (epoxy equivalent weight was 420 g / eq).

[0069] Take 32.08 g of water-based epoxy emulsifier (same as Example 1) and add it to the above prepared 246.79 g of solvent-free epoxy resin, mix, and react at 110°C for 30 min. After cooling to 60°C, emulsify slowly under high-speed stirring (3000 rpm) at a rate of 2 drops / S by adding 210.37 g of deionized water to obtain a solvent-free water-based epoxy film-forming material with a solid content of 57%, an average particle size of 350 nm, a fineness of 20 μm, and a milky white blue light emulsion.

[0070] Example 3

[0071] Put 32.6 g of tyrosine dipeptide (molecular weight 200.22), 92.52 g of epoxy chloropropane (molecular weight 92.52), and 27.6 g of potassium carbonate (molecular weight 138.21) into a 200 ml reaction kettle, stir and mix, and heat to 110°C for 3 h. The product after the reaction is a tyrosine dipeptide-based epoxy resin (molecular weight 308). Put 93.9 g of epoxy resin NPEF-170 and 84.51 g of tyrosine dipeptide-based epoxy resin and 48 g of bisphenol F into a 250 ml reaction kettle equipped with a stirring device and a thermometer, (the molar ratio of epoxy groups of the epoxy resin to phenolic hydroxyl groups of the bisphenol compound is 2.29:1), heat to 110°C to completely dissolve into a solution, then add 0.45 g of 4-methylammonium bromide (molecular weight 154.05) and heat to 115°C for 2.5 h to obtain a solvent-free epoxy resin (epoxy equivalent weight 400 g / eq).

[0072] Take 29.43 g of water-based epoxy emulsifier (same as Example 1) and add it to the above prepared 226.41 g of solvent-free epoxy resin, mix, and react at 100°C for 30 min. After cooling to 60°C, emulsify slowly under high-speed stirring (3000 rpm) at a rate of 2 drops / S by adding 209.32 g of deionized water to obtain a solvent-free water-based epoxy film-forming material with a solid content of 55%, an average particle size of 400 nm, a fineness of 30 μm, and a milky white emulsion.

[0073] The structural formula of the tyrosine dipeptide-based epoxy resin in this example is

[0074] Example 4

[0075] To a 250ml reaction kettle equipped with a stirrer and a thermometer, 93.9g of epoxy resin NPEF-170 and 84.51g of a tyrosine dipeptide-based epoxy resin (same as in Example 3) and 35g of tyrosine dipeptide and 24g of bisphenol F were added, and the mixture was dissolved into a solution at 110°C. After 0.51g of triphenylphosphine (molecular weight 262.29) was added, the temperature was raised to 130°C and maintained for 2 hours to obtain a solvent-free epoxy resin.

[0076] To 237.41g of the solvent-free epoxy resin prepared above, 30.86g of the water-based epoxy emulsifier (same as in Example 1) was added and mixed. The mixture was reacted at 120°C for 30 minutes. After the temperature was lowered to 60°C, 219.49g of deionized water was slowly added at a rate of 2 drops / s under high-speed stirring (3000rpm) to emulsify the mixture, thereby obtaining a solvent-free water-based epoxy film-forming material having a solid content of 55%, an average particle size of 420nm, a fineness of 35μm, and a milky white emulsion.

[0077] Comparative Example 1

[0078] To a 250ml reaction kettle equipped with a stirrer and a thermometer, 187.79g of epoxy resin E51 (molecular weight 378) and 32.8g of bisphenol A (molecular weight 228.29) were added, and the mixture was dissolved into a solution at 110°C. After 22.06g of dimer acid (molecular weight 500) was added, 0.52g of triphenylphosphine (molecular weight 262.29) was added, and the temperature was raised to 130°C and maintained for 2 hours to obtain a solvent-free epoxy resin.

[0079] To 242.65g of the solvent-free epoxy resin prepared above, 31.93g of the water-based epoxy emulsifier (same as in Example 1) was added and mixed. The mixture was reacted at 120°C for 30 minutes. After the temperature was lowered to 65°C, 210.13g of deionized water was slowly added at a rate of 2 drops / s under high-speed stirring (3000rpm) to emulsify the mixture, thereby obtaining a solvent-free water-based epoxy film-forming material having a solid content of 57%, an average particle size of 320nm, a fineness of 30μm, and a milky white emulsion with a blue tint.

[0080] Comparative Example 2

[0081] To a 250ml reaction kettle equipped with a stirrer and a thermometer, 187.79g of epoxy resin E51 (molecular weight 378) and 52g of bisphenol A (molecular weight 228.29) were added, and the mixture was dissolved into a solution at 110°C. After 0.54g of triphenylphosphine (molecular weight 262.29) was added, the temperature was raised to 130°C and maintained for 2 hours to obtain a solvent-free epoxy resin.

[0082] Take 31.17 g of water-based epoxy emulsifier (same as Example 1) and the above prepared 239.79 g of solvent-free epoxy resin, add 11.74 g of C12-14 alkyl glycidyl ether (molecular weight 300) and mix, react at 110°C for 30 min. After cooling to 60°C, emulsify under high speed stirring (3000 rpm) at a speed of 2 drops / S, add 227.35 g of deionized water slowly to obtain a solvent-free water-based epoxy film forming material, the solid content is 52%, the average particle size is 365.5 nm, the fineness is 30 μm, and the emulsion is milky white.

[0083] Experimental Example 1

[0084] The solvent-free water-based epoxy film forming materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested for related properties, and the test results are shown in Table 1.

[0085] Test method:

[0086] The content of the modifier in the emulsion: calculated theoretically;

[0087] Solid content: according to GB / 1725—1979, cut a tin foil paper of appropriate size, take about 1 g (accurate to 0.0001 g) of sample, place it in a 125°C oven and bake for 2 h, weigh after cooling, calculate the difference between the mass of the dried sample and the initial mass, and then obtain the solid content;

[0088] Viscosity: according to GB / 2314—2008, adjust the temperature of the emulsion to about 25°C, then test the prepared emulsion with NDJ-1 type rotary viscometer;

[0089] Fineness: measure the fineness of the emulsion according to GB / T 1724—1979, and test the prepared familiar epoxy resin using a fineness plate, test each sample in triplicate;

[0090] Particle size: use PSS laser particle size analyzer with water as the dispersion phase to measure the average particle size of the water-based epoxy resin;

[0091] Thermal storage stability: take an appropriate amount of water-based epoxy resin in a 100 ml thermal storage bottle and place it in a 50°C oven. Observe and record whether the water-based epoxy resin has water separation, softening, coarsening, emulsion breaking, viscosity increasing, etc. every two days. If there is no abnormality for 30 days, it is considered to pass.

[0092] Table 1 Test results of solvent-free water-based epoxy film forming materials

[0093]

[0094] As can be seen from Table 1, it can be found by Examples 1-4 that the base resin in the emulsion is mainly bisphenol F type epoxy resin, and the tyrosine dipeptide epoxy resin can be used in combination with the bisphenol F type epoxy resin. It can achieve complete 0 VOC, and has good viscosity and particle size, and the thermal storage is also relatively stable. If a conventional bisphenol A type epoxy resin system is used to prepare a waterborne epoxy resin similar to the present application, as can be found from Comparative Examples 1-2, a modifier (dimer acid and epoxy active diluent) must be used to modify the epoxy resin. Although similar emulsion parameters can be obtained as in the examples, the production cost is increased.

[0095] Experimental Example 2

[0096] The solvent-free waterborne epoxy film-forming materials prepared in Examples 1-4 and Comparative Examples 1-2 were respectively prepared into waterborne epoxy coating A component according to Table 2, and then mixed with AQUAC-3126 epoxy curing agent (Jiangsu Fuchisun) diluted with propylene glycol methyl ether and water at a ratio of 1:1 to prepare a paint with a molar ratio of epoxy to amine hydrogen of 1:0.8. The waterborne epoxy coating was then sprayed on a polished tinplate and cold-rolled steel plate to prepare a paint film. The paint film after construction was placed in a 80℃ oven for curing for 2h after leveling for 30min. The performance test was carried out after 24h, and the test results are shown in Table 3.

[0097] Table 2 A component formula composition

[0098]

[0099] Table 3 Test results of waterborne epoxy coating

[0100]

[0101] The above test results refer to the following test methods or standards: adhesion: the adhesion was determined by the grid method, GB / T 9286-1998; hardness: the pencil hardness of the paint film was determined, GB / T 6739-1996; flexibility: the flexibility of the paint film was determined, GB / T 1731-1993; impact resistance: the impact resistance of the paint film was determined, GB / T 1973-1993; the particle size of the epoxy resin was tested using a PSS particle size analyzer; 40℃ water resistance: GB / T 1733-1993; neutral salt spray resistance: GB / T 1771-2007.

[0102] As can be seen from the comparison results, by selecting low viscosity liquid epoxy resins: bisphenol F epoxy resin and tyrosine dipeptide epoxy resin as base resins, and using bisphenol F, tyrosine dipeptide and hydroquinone to increase the molecular weight of the epoxy resin, the solvent-free solid epoxy resin prepared by the present application has the following advantages compared with the prior art:

[0103] 1、The waterborne epoxy resin solid prepared by the present application is solid at room temperature, and does not contain any solvent, epoxy active diluent and dimer acid and other long carbon chain-containing flexible modifiers during the preparation process.

[0104] 2、The single functional diluent used in the prior art can reduce the crosslinking density of the coating, and further reduce the medium resistance of the coating, in addition, when the dimer acid is used to modify the preparation of the low solvent content bisphenol A type waterborne epoxy resin, the compatibility of the dimer acid and the bisphenol A type epoxy resin and the influence of the content of the waterborne epoxy resin on the thermal storage stability and medium resistance need to be considered, and the use amount of the dimer acid needs to be strictly screened, which leads to low tolerance of the resin formula. The above problems are effectively solved by the present application. Because the present application does not use a single functionality diluent, and there is no big difference in the compatibility between the reactants, the waterborne epoxy resin prepared by the present application has high 50℃ storage stability, and has higher formula design tolerance.

[0105] 3、It can be found from Comparative Examples 1-2 that the use of dimer acid and epoxy active diluent to modify the epoxy resin can obtain similar physical performance parameters to the examples, but the mechanical properties, water resistance and neutral salt spray resistance are far inferior to the examples of the present application.

[0106] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

[0107] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process for the preparation of a solvent-free waterborne epoxy film former, characterized in that, The preparation method comprises the following steps: 1) catalyzing the reaction of epoxy resin and bisphenol compound to obtain solvent-free epoxy resin; 2) mixing the solvent-free epoxy resin with water-based epoxy emulsifier to react, and then performing water phase reverse emulsification treatment to obtain solvent-free water-based epoxy film-forming material.

2. The method for preparing a solvent-free aqueous epoxy film-forming material according to claim 1, characterized in that, The epoxy resin in step 1) comprises bisphenol F type epoxy resin and / or tyrosine dipeptide based epoxy resin; The bisphenol compound comprises one or more of bisphenol F, tyrosine dipeptide and hydroquinone.

3. The method for preparing a solvent-free aqueous epoxy film-forming material according to claim 2, characterized in that, The molar ratio of epoxy group in the epoxy resin to phenolic hydroxyl group in the bisphenol compound in step 1) is 2.2-2.45:

1.

4. The method for preparing a solvent-free aqueous epoxy film-forming material according to claim 3, characterized in that, The temperature of the catalytic reaction in step 1) is 100-130℃, and the time is 2-3h; The catalyst of the catalytic reaction comprises one or more of guanidine, quaternary ammonium salt, quaternary ammonium base compound, triphenylphosphine compound and derivatives thereof; The amount of the catalyst in the catalytic reaction is 0.01-0.3% of the sum of the mass of the epoxy resin and the bisphenol compound.

5. The method according to any one of claims 1 to 4, characterized in that, The preparation method of the water-based epoxy emulsifier in step 2) comprises the following steps: first reaction of polyethylene glycol diglycidyl ether and difunctional polyether amine, second reaction of monofunctional polyether amine after the first reaction, to obtain modified polyether amine compound, and third reaction of the modified polyether amine compound and epoxy resin to obtain the water-based epoxy emulsifier; The molar ratio of the polyethylene glycol diglycidyl ether to the difunctional polyether amine is 2:1; The amount ratio of the polyethylene glycol diglycidyl ether to the monofunctional polyether amine is 2:1; The molar ratio of the polyethylene glycol diglycidyl ether to the epoxy resin is 1:4; The temperature of the first reaction is 60-80℃, and the time of the first reaction is 2-4h; The temperature of the second reaction is 100-120℃, and the time of the second reaction is 2-4h; The temperature of the third reaction is 100-120℃, and the time of the third reaction is 2-4h.

6. The method for preparing a solvent-free aqueous epoxy film-forming material according to claim 5, characterized in that, The mass ratio of the solvent-free epoxy resin to the water-based epoxy emulsifier in step 2) is 85-93:7-15.

7. The method for preparing a solvent-free aqueous epoxy film-forming material according to claim 6, characterized in that, The temperature of the reaction in step 2) is 100-130℃, and the time is 10-30min.

8. A method for preparing a solvent-free aqueous epoxy film-forming material according to claim 6 or 7, characterized in that, The water phase reverse emulsification treatment in step 2) is to add water dropwise into the solution after the reaction of the solvent-free epoxy resin and the water-based epoxy emulsifier, and perform shearing treatment; The mass ratio of the sum of the solvent-free epoxy resin and the water-based epoxy emulsifier to the mass of water is 1.1-1.4:1, the temperature of the water phase reverse emulsification treatment is 50-70℃, the dropwise adding speed of water is 2-5 drops / s, and the shearing speed is 2000-4000r / min.

9. The solvent-free water-based epoxy film-forming material prepared by the preparation method in any one of claims 1-8.

10. The application of the solvent-free water-based epoxy film-forming material in claim 9 in two-component water-based epoxy anticorrosive coating and adhesive.

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