Water-based self-emulsifying epoxy resin, preparation method, and aqueous dispersion containing the same

Abstract

The present invention relates to the technical field of waterborne epoxy resins, and discloses a waterborne self-emulsifying epoxy resin and a dispersion thereof. The components are measured by weight, including 40-55 parts of epoxy resin, 4-8 parts of mixed monomers, 0.02-0.1 parts of catalysts, and 0-60 parts of solvents; the components of the mixed monomers are measured by molar ratio, trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol=1:1-1.5:1-4:1-5:0.5-2.5; and a preparation method thereof is disclosed at the same time. The waterborne self-emulsifying epoxy dispersion prepared by the present application has a particle size of 0.3-0.5um, excellent storage stability, and VOC can be as low as zero. It is made into a two-component waterborne epoxy coating with excellent impact resistance, water resistance, salt spray resistance and corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of waterborne epoxy, in particular to a waterborne self-emulsifying epoxy resin, a preparation method and a water dispersion containing the same. Background Art

[0002] According to statistics, 40% of the coatings used worldwide each year are prepared with epoxy resin as the base resin. However, most of them are solvent-based coatings. With the gradual increase of people's awareness of environmental protection, and in order to eliminate the harm caused by organic solvents, many countries have formulated corresponding environmental protection laws and regulations to limit the emission of VOC (volatile organic compounds) and HAPs (hazardous air pollutants) in coatings, so that the coating industry will develop in the direction of low, high-efficiency, energy-saving, and eco-friendly greening.

[0003] Waterborne epoxy resin coating can not only be used as an energy-saving and environmentally friendly material, but its related physical and chemical properties, mechanical properties and process properties have reached a level comparable to those of solvent-based coatings. It also has the advantages of water-based systems such as being non-toxic and odorless, easy to construct, easy to clean, and safe to store and transport.

[0004] Water-based epoxy resin: generally divided into self-emulsification method and external emulsifier method.

[0005] The external emulsifier method, that is, obtaining an oil-in-water epoxy emulsion by adding an external emulsifier, has good emulsification effect and low dosage of special reactive emulsifiers; it improves the water resistance, chemical resistance and gloss of the coating. However, the curing agents used in the room temperature curing system are all water-soluble or water-dispersible amines or acrylic resins, which are all or partially hydrophilic. In order to obtain a coating with excellent performance, the curing agent and resin must have good compatibility, just like solvent-based coatings. Although the resin emulsion can be stabilized in water, it is still hydrophobic after all, which is very different from the hydrophilic curing agent in terms of physical properties, which naturally makes it difficult to ensure good coating performance.

[0006] The self-emulsifying method refers to the introduction of strong hydrophilic groups on the main chain of epoxy resin, so that the epoxy resin can be dispersed in water without the addition of emulsifiers. Self-emulsifying resin has the following advantages over the external emulsifier method: generally better stability (average particle size is smaller, generally 0.1-0.8um); improved compatibility between curing agent and resin; better quick drying; can be ground into color paste together with pigments and fillers, and can be made into lower or zero VOC products. However, most of the current self-emulsifying epoxy emulsions also have some problems: (1) The hardness of the cured film cannot be balanced with impact resistance and flexibility; (2) The water resistance and salt spray resistance are average and cannot reach the solvent type, which limits the use. Summary of the invention

[0007] <Technical Problems Solved by the Invention>

[0008] It is used to solve the technical problems in the prior art of epoxy emulsions where the hardness of the cured film and the impact resistance and flexibility cannot be balanced, and the water and salt spray resistance are far behind those of solvent-based epoxy emulsions.

[0009] <Technical solution adopted by the present invention>

[0010] In view of the above technical problems, the object of the present invention is to provide a water-based self-emulsifying epoxy resin, a preparation method, and a dispersion containing the same.

[0011] The specific contents are as follows:

[0012] First, the present invention provides a water-based self-emulsifying epoxy resin, wherein the components, by weight, include 40-55 parts of epoxy resin, 4-8 parts of mixed monomers, 0.02-0.1 parts of catalysts, and 0-60 parts of solvents; the components of the mixed monomers, by molar ratio,

[0013] Trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol = 1:1-1.5:1-4:1-5:0.5-2.5.

[0014] Second, the present invention provides a method for preparing the aforementioned water-based self-emulsifying epoxy resin, comprising the following steps:

[0015] S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer;

[0016] S2 reacts the epoxy resin, the hydrophilic polymer and the catalyst, and after the heat preservation is completed, adds an organic solvent for high-speed dispersion to obtain a water-based self-emulsifying epoxy resin with a solid content of 60-75%.

[0017] Third, the present invention provides a method for preparing an aqueous self-emulsifying epoxy dispersion, comprising the following steps:

[0018] S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer;

[0019] S2 reacts the epoxy resin, the hydrophilic polymer and the catalyst. After the heat preservation is completed, deionized water is added for high-speed dispersion, and a phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0020] <Technical mechanism and beneficial effects of the present invention>

[0021] (1) The present application uses polyethylene glycol / propylene glycol and polyethylene glycol monomethyl ether to provide hydrophilicity, trimethylolpropane triglycidyl ether and polyethylene glycol / propylene glycol diglycidyl ether to act as chain extenders to synthesize long-chain polyoxyethylene ethers with larger molecular weights, so that the resulting hydrophilic polymer has better hydrophilicity.

[0022] The ring structure of isosorbide can provide sufficient rigidity, improve the glass transition temperature and mechanical properties of the polymer, and can balance the hardness, impact resistance and flexibility of the cured film when combined with long-chain polyoxyethylene ether. Isosorbide has a low melting point (60-63°C) and can catalyze reactions at lower temperatures (<100°C), reduce side reactions, and have a uniform molecular weight distribution. It is much less toxic than bisphenol A and has higher environmental protection and safety.

[0023] (2) The use of isosorbide and polyoxyethylene ether to hydrophilically modify epoxy resin can make the modified epoxy resin self-emulsify into a uniform and stable emulsion without adding a co-solvent, with excellent storage stability and zero VOC emissions.

[0024] The self-emulsifying epoxy resin emulsion has a low particle size (0.3-0.5um) and good stability. It can be ground together with pigments and fillers. It has good compatibility with amine curing agents. The prepared two-component epoxy coating has excellent drying properties and water and salt spray resistance. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0026] First, the present invention provides a water-based self-emulsifying epoxy resin, wherein the components, by weight, include 40-55 parts of epoxy resin, 4-8 parts of mixed monomers, 0.02-0.1 parts of catalysts, and 0-60 parts of solvents; the components of the mixed monomers, by molar ratio,

[0027] Trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol = 1:1-1.5:1-4:1-5:0.5-2.5.

[0028] Furthermore, the components of the mixed monomer are measured by molar ratio,

[0029] Trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol = 1:1-1:1-3:1-3:0.5-2.

[0030] In the present invention, the organic solvent includes at least one of ethylene glycol tert-butyl ether, ethylene glycol butyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate and propylene glycol methyl ether.

[0031] In the present invention, the catalyst comprises at least one of boron trifluoride ethyl ether and triphenylphosphine.

[0032] In the present invention, the polyethylene glycol / propylene glycol diglycidyl ether has an average molecular weight of 400-1000;

[0033] Polyethylene glycol monomethyl ether has an average molecular weight of 500-2000;

[0034] The average molecular weight of polyethylene glycol / propylene glycol is 1000-8000.

[0035] In the present invention, the epoxy resin is bisphenol A or bisphenol F epoxy resin, and the epoxy equivalent is 0.2-0.51.

[0036] Second, the present invention provides a method for preparing the aforementioned water-based self-emulsifying epoxy resin, comprising the following steps:

[0037] S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer;

[0038] S2 reacts the epoxy resin, the hydrophilic polymer and the catalyst, and after the heat preservation is completed, adds an organic solvent for high-speed dispersion to obtain a water-based self-emulsifying epoxy resin with a solid content of 60-75%.

[0039] Third, the present invention provides a method for preparing the aforementioned aqueous self-emulsifying epoxy dispersion, comprising the following steps:

[0040] S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer;

[0041] S2 reacts the epoxy resin, the hydrophilic polymer and the catalyst. After the heat preservation is completed, deionized water is added for high-speed dispersion, and a phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0042] In the present invention, in S1, the reaction temperature is 80-100° C. and the temperature is kept for 0.5-4 h.

[0043] In the present invention, in S2, the temperature is raised to 80-120°C and kept warm for 2-4 hours.

[0044] <Example>

[0045] Example 1

[0046] A method for preparing an aqueous self-emulsifying epoxy dispersion comprises the following steps:

[0047] S1 0.22 parts of trimethylolpropane triglycidyl ether, 1.44 parts of polyethylene glycol monomethyl ether (M=2000) and 0.01 parts of boron trifluoride etherate, react at 85-95°C, keep warm for 0.5h, add 0.21 parts of isosorbide, 0.36 parts of polyethylene glycol / propylene glycol diglycidyl ether (M=500), 5.78 parts of polyethylene glycol / propylene glycol (M=8000) and 0.01 parts of boron trifluoride etherate, react at 85-95°C, keep warm for 4h to obtain a hydrophilic polymer;

[0048] S2: 31.5 parts of bisphenol A epoxy resin E44, 13.5 parts of bisphenol A epoxy resin E20, 8 parts of hydrophilic polymer and 0.05 parts of triphenylphosphine are reacted at 110-120°C, kept warm for 3 hours, 47 parts of deionized water are added for high-speed dispersion, and phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0049] Example 2

[0050] A method for preparing an aqueous self-emulsifying epoxy dispersion comprises the following steps:

[0051] S1 0.18 parts of trimethylolpropane triglycidyl ether, 0.43 parts of polyethylene glycol monomethyl ether (M=500) and 0.01 parts of boron trifluoride etherate, react at 80-90°C, keep warm for 0.5h, add 0.22 parts of isosorbide, 0.61 parts of polyethylene glycol / propylene glycol diglycidyl ether (M=500), 4.86 parts of polyethylene glycol / propylene glycol (M=8000) and 0.013 parts of boron trifluoride etherate, react at 80-90°C, keep warm for 2h to obtain a hydrophilic polymer;

[0052] S2: 36 parts of bisphenol A epoxy resin E44, 9 parts of bisphenol A epoxy resin E20, 6.3 parts of hydrophilic polymer and 0.05 parts of triphenylphosphine are reacted at 110-120°C, kept warm for 2 hours, 8 parts of ethylene glycol tert-butyl ether and 40.6 parts of deionized water are added and dispersed at high speed, and phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0053] Example 3

[0054] A method for preparing an aqueous self-emulsifying epoxy dispersion comprises the following steps:

[0055] S1 0.28 parts of trimethylolpropane triglycidyl ether, 0.93 parts of polyethylene glycol monomethyl ether (M=1000) and 0.01 parts of boron trifluoride ether were reacted at 80-90°C, and kept warm for 0.5h, and then 0.27 parts of isosorbide, 0.46 parts of polyethylene glycol / propylene glycol diglycidyl ether (M=500), 5.56 parts of polyethylene glycol / propylene glycol (M=6000) and 0.013 parts of boron trifluoride ether were added, and the mixture was reacted at 80-90°C and kept warm for 2h to obtain a hydrophilic polymer;

[0056] S2: 24 parts of bisphenol A epoxy resin E51, 24 parts of bisphenol A epoxy resin E20, 7.5 parts of hydrophilic polymer and 0.02 parts of triphenylphosphine are reacted at 110-120°C, kept warm for 3 hours, 5 parts of propylene glycol methyl ether and 39.5 parts of deionized water are added and dispersed at high speed, and phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0057] Example 4

[0058] A method for preparing an aqueous self-emulsifying epoxy dispersion comprises the following steps:

[0059] S1 0.15 parts of trimethylolpropane triglycidyl ether, 0.48 parts of polyethylene glycol monomethyl ether (M=1000) and 0.01 parts of boron trifluoride ether were reacted at 80-90°C, and kept warm for 1 hour, and then 0.21 parts of isosorbide, 1.92 parts of polyethylene glycol / propylene glycol diglycidyl ether (M=1000), 3.84 parts of polyethylene glycol / propylene glycol (M=4000) and 0.006 parts of boron trifluoride ether were added, and the mixture was reacted at 80-90°C and kept warm for 4 hours to obtain a hydrophilic polymer;

[0060] S2: 33 parts of bisphenol A epoxy resin E44, 11 parts of bisphenol A epoxy resin E20, 6.6 parts of hydrophilic polymer and 0.015 parts of boron trifluoride etherate are reacted at 80-90°C, kept warm for 4 hours, 49.5 parts of deionized water are added for high-speed dispersion, and phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

[0061] <Comparative Example>

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 3 is that isosorbide is not added, and the amount of isosorbide is replaced by polyethylene glycol (M=1000) in an equimolar manner.

[0064] Comparative Example 2

[0065] This comparative example is basically the same as Example 2, except that the amount of the hydrophilic polymer added is 60% of the original amount.

[0066] <Test example>

[0067] Examples 1-4 and comparative examples 1-2 are used as samples, wherein the example is represented by E and the comparative example is represented by C.

[0068] (1) The samples were tested for their indexes. The results are shown in Table 1.

[0069] Table 1 Various indicators of water-based self-emulsifying epoxy dispersion

[0070] index E1 E2 E3 E4 C1 C2 Solid content / % 53 51 55 50 55 51 Appearance White emulsion White emulsion White emulsion White emulsion White emulsion White emulsion Storage stability (d) ＞90 ＞90 ＞90 ＞90 ＞90 ＝6d

[0071] (2) Add the sample to the paint and measure the paint film properties.

[0072] Component A

[0073] The preparation method comprises the following steps: grinding 22 parts of deionized water, 11 parts of dispersants Tego-755w and Troysperse-ZWD, 0.1 parts of defoaming agent Tego-902w, 0.1 parts of defoaming agent Tego-822, 0.3 parts of wetting agent Tego-41000, 0.2 parts of bentonite, 0.3 parts of gas silica, 4 parts of titanium dioxide, 19 parts of barium sulfate, 3 parts of zinc phosphate, 3 parts of mica powder, 4 parts of zinc strontium phosphate and 40-42 parts of aqueous self-emulsifying epoxy dispersion at 1500 r / min for 1 hour, dispersing to less than 30 μm, and obtaining a first mixture; adding 1 part of propylene glycol butyl ether, 1 part of dipropylene glycol butyl ether, 1 part of adhesion promoter MP200 (Maitu), appropriate amounts of polyurethane thickener and color paste to the first mixture, stirring at 800 r / min for 10 minutes, and obtaining a coating.

[0074] Component B

[0075] The preparation method is as follows: 70 parts of Fuqisen water-based polyamine adduct 3128 (solid content 50%, active hydrogen equivalent 195), 3 parts of anti-flash rust agent CK45 (Qingdao Enze), 17 parts of propylene glycol methyl ether, and 10 parts of water.

[0076] Component A: component B = 10:1.

[0077] The performance of the coating prepared above was measured in the test environment, the temperature was greater than 20°C, the humidity was less than 65%, the substrate was tinplate, and the dry film thickness was 100±10um (two sprayings, 24h interval). The measurement results are shown in Table 2.

[0078] Table 2 Paint film performance determination

[0079]

[0080]

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A water-based self-emulsifying epoxy resin, characterized in that The components are calculated by weight, including 40-55 parts of epoxy resin, 4-8 parts of mixed monomers, 0.02-0.1 parts of catalysts, and 0-60 parts of organic solvents; the components of the mixed monomers are calculated by molar ratio, Trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol = 1:1-1.5:1-4:1-5:0.5-2.5; The preparation method of water-based self-emulsifying epoxy resin comprises the following steps: S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer; S2 The epoxy resin, the hydrophilic polymer and the catalyst are reacted, and after the heat preservation is completed, an organic solvent is added and dispersed at a high speed to obtain a water-based self-emulsifying epoxy resin with a solid content of 60-75%.

2. The water-based self-emulsifying epoxy resin according to claim 1, characterized in that The solvent includes at least one of ethylene glycol tert-butyl ether, ethylene glycol butyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, and propylene glycol methyl ether.

3. The water-based self-emulsifying epoxy resin according to claim 1, characterized in that: The catalyst includes at least one of boron trifluoride ethyl ether and triphenylphosphine.

4. The water-based self-emulsifying epoxy resin according to any one of claims 1 to 3, characterized in that The average molecular weight of polyethylene glycol / propylene glycol diglycidyl ether is 400-1000; The average molecular weight of polyethylene glycol monomethyl ether is 500-2000; The average molecular weight of polyethylene glycol / propylene glycol is 1000-8000.

5. The water-based self-emulsifying epoxy resin according to any one of claims 1 to 3, characterized in that The epoxy resin is bisphenol A or bisphenol F epoxy resin, and the epoxy equivalent is 0.2-0.

51.

6. A method for preparing an aqueous self-emulsifying epoxy dispersion, characterized in that: The steps include: The components of the aqueous self-emulsifying epoxy dispersion are calculated by weight, including 40-55 parts of epoxy resin, 4-8 parts of mixed monomers, 0.02-0.1 parts of catalysts, and 0 parts of organic solvents; when the organic solvent is 0 parts, deionized water is added; The components of the mixed monomer are measured by molar ratio, Trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether, polyethylene glycol / propylene glycol = 1:1-1.5:1-4:1-5:0.5-2.5; S1 trimethylolpropane triglycidyl ether, polyethylene glycol monomethyl ether and a part of the catalyst are reacted, and after the heat preservation is completed, isosorbide, polyethylene glycol / propylene glycol diglycidyl ether are added, and polyethylene glycol / propylene glycol and the catalyst are continued to react to obtain a hydrophilic polymer; S2: The epoxy resin, the hydrophilic polymer and the catalyst are reacted. After the heat preservation is completed, deionized water is added for high-speed dispersion, and a phase inversion is performed to obtain an aqueous self-emulsifying epoxy dispersion.

7. The method for preparing an aqueous self-emulsifying epoxy dispersion according to claim 6, characterized in that: In S1, the reaction temperature is 80~100°C and the temperature is kept for 0.5~4h.

8. The method for preparing an aqueous self-emulsifying epoxy dispersion according to claim 6 or 7, characterized in that: In S2, raise the temperature to 80~120℃ and keep it warm for 2~4h.

Images