A high-performance water-based epoxy resin emulsion and its preparation method and application

Abstract

The invention discloses a high-performance water-based epoxy resin emulsion and a preparation method and application thereof. The water-based epoxy resin emulsion comprises the following raw materials in parts by weight: 40-60 parts of epoxy resin, 2-2.5 parts of emulsifier, 0.5-4 parts of solvent and 40-60 parts of water; the emulsifier comprises the following raw materials in parts by weight: 100-600 parts of alkanol, 20-250 parts of glycidyl ether epoxy resin, 5-30 parts of alcohol ether and 0.1-3 parts of catalyst; the emulsifier further comprises polyethylene polyamine, wherein the weight ratio of the polyethylene polyamine to the glycidyl ether epoxy resin is 1-2:100. The water-based epoxy resin emulsion prepared by the invention has excellent mechanical stability and storage stability. Compared with the prior art, the water-based epoxy resin emulsion can be ground together with a pigment without demulsification, thereby avoiding the problem of inaccurate coloring caused by grinding an active pigment with a curing agent together, and the formed paint film also has excellent water and salt spray resistance.

Description

Technical Field

[0001] The invention belongs to the field of epoxy resin coatings, and in particular relates to a high-performance water-based epoxy resin emulsion and a preparation method and application thereof. Background Art

[0002] The benzene ring groups contained in the chemical structure of epoxy resin emulsion have good chemical resistance, corrosion resistance and mechanical properties. The hydroxyl groups it contains have excellent adhesion to metal substrates. After reacting with a curing agent, it can form a dense three-dimensional network polymer film. It is widely used in anti-corrosion coatings, adhesives, industrial flooring and other fields.

[0003] Traditional solvent-based two-component epoxy coatings contain a large amount of volatile organic compounds, which are extremely harmful to the environment and human body. Therefore, most of the existing two-component epoxy resin coatings are water-based epoxy resins, which have the advantages of low VOC and less environmental pollution, and are gradually becoming the future development trend of environmentally friendly industrial anti-corrosion coatings.

[0004] Most two-component epoxy resin coatings include two components: a water-based epoxy resin emulsion and a curing agent. When used, the two components are first mixed and then applied. A paint film is formed after curing. The two-component design of epoxy resin emulsion and curing agent mostly requires the pigment to be ground and toned before mixing. The existing grinding and toning operations are generally carried out by mixing with the curing agent, and the curing agent sometimes affects the color presentation of the pigment (especially the active pigment). However, the grinding and toning operations cannot be transferred to mixing with the epoxy resin emulsion, because if the conventional epoxy resin emulsion is ground together with the pigment, it will cause demulsification, the epoxy resin emulsion system will be destroyed, and then the performance of the paint film after curing will be affected.

[0005] In summary, the present invention aims to provide a high-performance water-based epoxy resin emulsion, which can be ground and toned together with a pigment without demulsification and thus affecting the performance of the paint film, and the paint film also has excellent water and salt spray resistance. Summary of the invention

[0006] In view of the problems in the related art, the present invention proposes a structural design of an emulsifier, and designs a specific emulsion formula and ratio for the emulsifier, that is, provides a high-performance water-based epoxy resin emulsion. The present invention also discloses a preparation method and application of the water-based epoxy resin emulsion to overcome the above-mentioned technical problems existing in the existing related art.

[0007] The technical solution of the present invention is achieved in this way:

[0008] A high-performance water-based epoxy resin emulsion comprises the following raw materials in parts by weight: 40-60 parts of epoxy resin, 2-2.5 parts of emulsifier, 0.5-4 parts of solvent, and 40-60 parts of water;

[0009] The emulsifier comprises the following raw materials in parts by weight: 100-600 parts of alkanol, 20-250 parts of glycidyl ether epoxy resin, 5-30 parts of alcohol ether and 0.1-3 parts of catalyst;

[0010] The emulsifier further comprises polyethylene polyamine, and the weight ratio of the polyethylene polyamine to the glycidyl ether epoxy resin is 1-2:100.

[0011] The alkanol takes polyethylene glycol as an example, and the synthesis reaction is as shown in the following figure:

[0012]

[0013] The above-mentioned amphiphilic emulsifier small molecules already have basic emulsifying ability, but in order to obtain a high-efficiency emulsifier with a low addition amount in the present invention, a certain proportion of polyethylene polyamine needs to be specifically designed to graft multiple emulsifier small molecules, thereby extending the chain to form a larger molecular emulsifier.

[0014] The polyethylene polyamine is described by taking diethylenetriamine as an example, and the further synthesis reaction is as shown in the following figure:

[0015]

[0016] The waterborne epoxy resin emulsion prepared by the invention has excellent mechanical stability and storage stability. Compared with the prior art, it can be ground together with the pigment without demulsification, thus avoiding the problem of inaccurate coloring caused by grinding the active pigment and the curing agent together. At the same time, the formed paint film also has excellent water and salt spray resistance.

[0017] Preferably, the average particle size of the waterborne epoxy resin emulsion is 250nm-450nm, and the D100 particle size is <800nm. The particle size is small, and aggregation between emulsion molecules is not easy to occur, so that the waterborne epoxy resin emulsion prepared by the present invention is not easy to delaminate and the subsequently cured paint film has good water and salt spray resistance.

[0018] The emulsifier specifically developed by the present invention can be applied to most of the epoxy resins available on the market, such as bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, etc. However, the inventors have found through experiments that the emulsifier is particularly suitable for bisphenol A epoxy resin. The prepared emulsion can maintain an emulsion system with a small particle size under high-speed shearing of 2000-3000rpm, and there is no coarseness or demulsification when ground together with the pigment. Preferably, the epoxy resin is bisphenol A epoxy resin; more preferably, the bisphenol A epoxy resin is one of E51, E44, E20, E06 or a mixture of any proportion of more than one.

[0019] Preferably, the solvent is one of propylene glycol methyl ether and ethylene glycol monobutyl ether, or a mixture of the two in any proportion.

[0020] Preferably, the polyethylene polyamine is one or more of diethylene triamine, triethylene tetramine, and tetraethylene pentamine mixed in any proportion. The polyethylene polyamine is used to connect multiple small emulsifier molecules to form a larger molecular emulsifier, and at the same time, it is necessary to ensure that the active hydrogen is completely reacted. If the number of functional groups of the polyethylene polyamine is too large, the small emulsifier molecules grafted first form steric hindrance, which will make it difficult for some active hydrogen to undergo grafting reaction, which is not conducive to the subsequent preparation of a stable epoxy resin emulsion.

[0021] In addition, compared with other grafted materials, the polyethylene polyamine selected in the present invention can effectively complete the reaction and avoid excessive cross-linking because the functional groups are appropriately spaced and fully exposed. At the same time, it does not require an excessively high reaction temperature when designing the preparation process, which can save production costs and improve production efficiency to a certain extent.

[0022] Preferably, the alkanol is one of polyethylene glycol and polypropylene glycol or a mixture of the two in any proportion. If the selected alkanol has too many methyl groups in the repeating unit, it will have an adverse effect on the hydrophilicity of the emulsifier of the present invention; if the selected alkanol has too many hydroxyl groups in the repeating unit, the hydrophilicity is too strong, affecting the emulsification ability and the performance of the paint film after curing; in addition, polyethylene glycol and polypropylene glycol are low in price, which is conducive to controlling production costs.

[0023] Preferably, the molecular weight of the polyethylene glycol is 1000-10000, and the molecular weight of the polypropylene glycol is 1000-5000. More preferably, the molecular weight of the polyethylene glycol is 2000-6000, and the molecular weight of the polypropylene glycol is 2000-3000. The use of an alkanol with a molecular weight that is too large will cause the emulsifier prepared by the present invention to be too hydrophilic, destroying the balance between hydrophilicity and hydrophobicity, and affecting the emulsification ability of the present invention. The use of an alkanol with a molecular weight that is too small will cause the hydrophilic chain in the emulsifying molecule to be too short.

[0024] The epoxy resin and the glycidyl ether epoxy resin can be solid, semi-solid or liquid. Compared with alkanol, alcohol ether has a better solubility for the glycidyl ether epoxy resin. Therefore, a certain number of alcohol ethers are set to make the glycidyl ether epoxy resin fully dissolved in the reaction system. Preferably, the alcohol ether is one or more of propylene glycol methyl ether and ethylene glycol monobutyl ether mixed in any proportion. Both have a low boiling point and saturated vapor pressure, which is convenient for subsequent removal. Even if there is a trace amount of residue, it can be volatilized when the paint film is made.

[0025] Preferably, the catalyst is HBF4 aqueous solution, triphenylphosphine, or triphenylphosphine and HBF4 aqueous solution added successively. More preferably, the catalyst is triphenylphosphine and HBF4 aqueous solution added successively in a weight ratio of 1:0.5-1, and the mass concentration of the HBF4 aqueous solution is 50-55%. The inventors found in the research and development process that it is difficult to achieve complete reaction using a single catalyst, and adding two catalysts successively can better solve this problem.

[0026] Preferably, the glycidyl ether epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, and novolac epoxy resin mixed in any proportion. More preferably, the glycidyl ether epoxy resin is bisphenol A epoxy resin, and the bisphenol A epoxy resin is one or more of E51, E44, E20, and E06 mixed in any proportion.

[0027] The method for preparing the above-mentioned high-performance water-based epoxy resin emulsion comprises the following steps:

[0028] (1) Adding a preset weight amount of epoxy resin and solvent into a reaction stirring device, adjusting the temperature to 75-95° C., and then stirring at a constant temperature until all dissolved, that is, the mixed material is transparent, and the rotation speed is 50-80 rpm;

[0029] (2) adjusting the temperature to 85-95° C., maintaining a constant temperature, adding a preset amount of emulsifier by weight, rotating at 200-500 rpm, and stirring for at least 20 minutes;

[0030] (3) adjusting the rotation speed to 1800-2200 rpm, slowly adding a preset amount of water by weight to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing the high-performance water-based epoxy resin emulsion.

[0031] Preferably, the preparation method of the emulsifier comprises the following steps:

[0032] (1) adding a preset weight amount of alkanol and alcohol ether to a stirring reaction device. Since alkanol is unstable at high temperature, premixing of alkanol and alcohol ether can make the alkanol molecules evenly heated during the heating process and accelerate the melting process. At the same time, an inert gas is introduced to protect the alkanol. The temperature is raised to 90-130° C. and kept constant for at least 1 hour to ensure complete melting. During the reaction process, the moisture in the system will be taken away by the inert gas flow that is continuously introduced, so as to prevent the moisture in the system from affecting the subsequent reaction;

[0033] (2) maintaining the temperature, adding a predetermined amount of catalyst by weight, and stirring at 180-220 rpm for at least 5 minutes;

[0034] (3) maintaining the temperature, adding a preset weight portion of glycidyl ether epoxy resin, stirring at 180-220 rpm for at least 5 hours, until the conversion rate is ≥95%;

[0035] (4) removing alcohol ethers;

[0036] (5) Setting the temperature to 100°C, stirring at 180-220 rpm, adding polyethylene polyamine in a dropwise manner at a rate of 2-3 g / min, raising the temperature to 120°C after the addition is complete, and reacting for at least 3 hours until the reaction is complete;

[0037] (6) Cooling down to ≤90°C, the finished product obtained in step (5) and water are prepared in a weight ratio of 1:0.8-1.2, and water is slowly added to the finished product obtained in step (5) to obtain the emulsifier. If water is added quickly, it will cause excessive water in the local area, which will directly promote the self-emulsification of the emulsifier. If no water is added, the emulsifier will be solid after cooling, which is not convenient for the subsequent mixing preparation of the epoxy resin emulsion. Deionized water is preferably used.

[0038] The preparation process of the present invention is coherent and streamlined. The prepared emulsifier product contains broadly distributed emulsifier molecules, that is, emulsifiers with different molecular weights do not need to be produced separately and then mixed. At the same time, specific preparation steps and parameters are designed for the emulsifier. The streamlined process makes the corresponding production equipment assembly line design more concise, which saves the production cost of the enterprise and improves the production efficiency.

[0039] Preferably, in step (2) of preparing the emulsifier, the specific operation of adding the catalyst is: first add a preset weight portion of triphenylphosphine, stir at 100°C for at least 5 minutes, then add a preset weight portion of HBF4 aqueous solution with a mass concentration of 50%, and stir for at least 5 minutes.

[0040] Preferably, in step (4) of preparing the emulsifier, the temperature is set to 120-150° C., and the alcohol ether is removed by distillation under reduced pressure.

[0041] The application of the above high-performance water-based epoxy resin emulsion is that the water-based epoxy resin emulsion and the amine curing agent are mixed in a weight ratio of 1:0.1-0.3. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The test results of the water resistance test of Example 1;

[0043] Figure 2 The test results of the salt spray resistance test of Example 1 are shown. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Unless otherwise specified, the raw materials used in this example are all commercially available conventional raw materials.

[0046] Example 1

[0047] A. Preparation of emulsifier

[0048] (1) Add 400 g of polyethylene glycol 4000 and 20 g of propylene glycol methyl ether into a 1 L glass reactor, introduce inert gas, raise the temperature to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0049] (2) Maintaining temperature, 2 g HBF4 aqueous solution (50 wt%), stirring at 200 rpm for 5 minutes;

[0050] (3) Maintaining the temperature, add 52 g of glycidyl ether epoxy resin (bisphenol A type E51), and stir at 200 rpm for 5 hours;

[0051] (4) heating to 120° C. and performing reduced pressure distillation to remove propylene glycol methyl ether;

[0052] (5) The temperature was then set to 100°C, the mixture was stirred at 200 rpm, 1.0 g of diethylenetriamine was added at a rate of 2 g / min, and the temperature was raised to 120°C after the addition was complete, and the reaction was continued for 3 hours;

[0053] (6) The temperature was lowered to 90° C., and 450 g of deionized water was slowly added to the finished product obtained in step (5) to obtain an emulsifier.

[0054] B. Preparation of high-performance waterborne epoxy resin emulsion

[0055] (1) Add 450 g of E20 solid epoxy resin and 30 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 95° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0056] (2) Adjust the temperature to 85°C, keep the temperature constant, add 20 g of emulsifier, rotate at 300 rpm, and stir for 20 minutes;

[0057] (3) Adjust the rotation speed to 2000 rpm, slowly add 400 g of deionized water to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing a high-performance water-based epoxy resin emulsion.

[0058] Example 2

[0059] A. Preparation of emulsifier

[0060] (1) Add 400 g of polyethylene glycol 8000 and 25 g of ethylene glycol monobutyl ether into a 1 L glass reactor, introduce inert gas, raise the temperature to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0061] (2) Maintaining the temperature, add 1 g of triphenylphosphine, stir for 5 minutes, then add 0.8 g of HBF4 aqueous solution (50 wt%), and stir at 200 rpm for 5 minutes;

[0062] (3) Maintaining the temperature, add 28 g of glycidyl ether epoxy resin (bisphenol A type E51), and stir at 200 rpm for 5 hours;

[0063] (4) heating to 145° C. and performing vacuum distillation to remove ethylene glycol monobutyl ether;

[0064] (5) The temperature was then set to 100°C, the mixture was stirred at 200 rpm, 0.5 g of diethylenetriamine was added at a rate of 2.5 g / min, and the temperature was raised to 120°C after the addition was complete, and the reaction was continued for 3 hours;

[0065] (6) The temperature was then lowered to 90° C., and 420 g of deionized water was slowly added to the finished product obtained in step (5) to obtain an emulsifier.

[0066] B. Preparation of high-performance waterborne epoxy resin emulsion

[0067] (1) Add 450 g of E44 liquid epoxy resin and 10 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 75° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0068] (2) Adjust the temperature to 85°C, keep the temperature constant, add 20 g of emulsifier, rotate at 300 rpm, and stir for 20 minutes;

[0069] (3) Adjust the rotation speed to 2000 rpm, slowly add 400 g of deionized water to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing a high-performance water-based epoxy resin emulsion.

[0070] Example 3

[0071] A. Preparation of emulsifier

[0072] (1) Add 400 g of polyethylene glycol 2000, 100 g of polypropylene glycol 2000 and 25 g of ethylene glycol monobutyl ether into a 1 L glass reactor, introduce inert gas, heat to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0073] (2) Maintaining the temperature, add 1 g of triphenylphosphine, stir for 5 minutes, then add 0.8 g of HBF4 aqueous solution (50 wt%), and stir at 200 rpm for 5 minutes;

[0074] (3) Maintaining the temperature, add 211 g of glycidyl ether epoxy resin (bisphenol A type E44), and stir at 200 rpm for 5 hours;

[0075] (4) heating to 120° C. and performing vacuum distillation to remove ethylene glycol monobutyl ether;

[0076] (5) The temperature was then set to 100°C, the mixture was stirred at 200 rpm, 3.7 g of diethylenetriamine was added at a rate of 3 g / min, and the temperature was raised to 120°C after the addition was complete, and the reaction was continued for 3 hours;

[0077] (6) The temperature was then lowered to 90° C., and 720 g of deionized water was slowly added to the finished product obtained in step (5) to obtain an emulsifier.

[0078] B. Preparation of high-performance waterborne epoxy resin emulsion

[0079] (1) Add 450 g of E20 liquid epoxy resin and 10 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 75° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0080] (2) Adjust the temperature to 85°C, keep the temperature constant, add 20 g of emulsifier, rotate at 300 rpm, and stir for 20 minutes;

[0081] (3) Adjust the rotation speed to 2000 rpm, slowly add 400 g of deionized water to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing a high-performance water-based epoxy resin emulsion.

[0082] Comparative Example 1

[0083] A. Preparation of emulsifier

[0084] (1) Add 400 g of polyethylene glycol 4000 and 20 g of propylene glycol methyl ether into a 1 L glass reactor, introduce inert gas, raise the temperature to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0085] (2) Maintaining temperature, 2 g HBF4 aqueous solution (50 wt%), stirring at 200 rpm for 5 minutes;

[0086] (3) Maintaining the temperature, add 52 g of bisphenol A epoxy resin (E51) and stir at 200 rpm for 5 hours;

[0087] (4) Raising the temperature to 120° C. and performing reduced pressure distillation to remove propylene glycol methyl ether to obtain an emulsifier.

[0088] B. Preparation of waterborne epoxy resin emulsion

[0089] (1) Add 450 g of E20 solid epoxy resin and 30 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 95° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0090] (2) Adjust the temperature to 85°C, keep the temperature constant, add 20 g of emulsifier, rotate at 300 rpm, and stir for 20 minutes;

[0091] (3) The rotation speed was adjusted to 2000 rpm, and 400 g of deionized water was slowly added to form a phase inversion, and the mixed material turned into a uniform milky white color, thus preparing this comparative example.

[0092] Comparative Example 2

[0093] A. Preparation of emulsifier

[0094] (1) Add 400 g of polyethylene glycol 4000 and 40 g of propylene glycol methyl ether into a 1 L glass reactor, introduce inert gas, raise the temperature to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0095] (2) Maintaining temperature, 2 g HBF4 aqueous solution (50 wt%), stirring at 200 rpm for 5 minutes;

[0096] (3) Maintaining the temperature, add 52 g of bisphenol A epoxy resin (E51) and stir at 200 rpm for 5 hours;

[0097] (4) heating to 120° C. and performing reduced pressure distillation to remove propylene glycol methyl ether;

[0098] (5) The temperature was then set to 100°C, the mixture was stirred at 200 rpm, and 1.3 g of diethylenetriamine was added at a rate of 2 g / min. After the addition was complete, the temperature was raised to 120°C and the mixture was reacted for 3 hours.

[0099] (6) The temperature was lowered to 90° C., and 450 g of deionized water was slowly added to the finished product obtained in step (5) to obtain an emulsifier.

[0100] B. Preparation of waterborne epoxy resin emulsion

[0101] (1) Add 450 g of E20 solid epoxy resin and 30 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 95° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0102] (2) Adjust the temperature to 85°C, keep the temperature constant, add 20 g of emulsifier, rotate at 300 rpm, and stir for 20 minutes;

[0103] (3) The rotation speed was adjusted to 2000 rpm, and 400 g of deionized water was slowly added to form a phase inversion, and the mixed material turned into a uniform milky white color, thus preparing this comparative example.

[0104] Comparative Example 3

[0105] A. Preparation of emulsifier

[0106] (1) Add 400 g of polyethylene glycol 4000 and 20 g of propylene glycol methyl ether into a 1 L glass reactor, introduce inert gas, raise the temperature to 100 ° C and keep the temperature constant for 1 hour to fully dissolve;

[0107] (2) Maintaining temperature, 2 g HBF4 aqueous solution (50 wt%), stirring at 200 rpm for 5 minutes;

[0108] (3) Maintaining the temperature, add 52 g of glycidyl ether epoxy resin (bisphenol A type E51), and stir at 200 rpm for 5 hours;

[0109] (4) heating to 120° C. and performing reduced pressure distillation to remove propylene glycol methyl ether;

[0110] (5) The temperature was then set to 100°C, the mixture was stirred at 200 rpm, 1.0 g of diethylenetriamine was added at a rate of 2 g / min, and the temperature was raised to 120°C after the addition was complete, and the reaction was continued for 3 hours;

[0111] (6) The temperature was lowered to 90° C., and 450 g of deionized water was slowly added to the finished product obtained in step (5) to obtain an emulsifier.

[0112] B. Preparation of high-performance waterborne epoxy resin emulsion

[0113] (1) Add 450 g of E20 solid epoxy resin and 30 g of propylene glycol methyl ether to a 1 L glass reactor, adjust the temperature to 95° C., and then stir at a constant temperature until all dissolved, that is, the mixture is transparent, and rotate at 60 rpm;

[0114] (2) Adjust the temperature to 100°C, keep the temperature constant, add 20 g of emulsifier, rotate at 500 rpm, and stir for 20 minutes;

[0115] (3) Adjust the rotation speed to 2000 rpm, slowly add 400 g of deionized water to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing a high-performance water-based epoxy resin emulsion.

[0116] 1. Determination of epoxy equivalent

[0117] Epoxy equivalent refers to the mass of epoxy resin corresponding to 1 mol of epoxy group, and the unit is g / mol. The present invention adopts the hydrochloric acid acetone method to measure the epoxy equivalent of step (3) and step (5) of "A. Preparation of emulsifier" in Example 1-3 and Comparative Example 1-2, respectively.

[0118]

[0119] 2. Determination of particle size distribution

[0120] The particle sizes of Examples 1-3 and Comparative Examples 1-3 were measured by a laser particle size analyzer.

[0121] Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Average particle size / nm 256 612 353 926 622 736 D100 / nm 687 1128 810 2054 1189 1073

[0122] 3. Test the water solubility of the emulsifier and the storage stability, dilution stability and mechanical stability of the emulsion

[0123] (1) The emulsions prepared in Examples 1-3 and Comparative Examples 1-3 were packaged in equal amounts and placed at 50° C. for 2 months.

[0124] (2) Take equal amounts of the emulsions prepared in Examples 1-3 and Comparative Examples 1-3, dilute them by 2 times, and store them at room temperature for 2 months.

[0125] (3) Take equal amounts of the emulsions prepared in Examples 1-3 and Comparative Examples 1-3 and subject them to high-speed shearing at 2500 rpm for 3 hours.

[0126] (4) Take an equal amount of the emulsions prepared in Examples 1-3 and Comparative Examples 1-3 and grind them together with the powder in a horizontal sand mill at 2500 rpm for 6 times.

[0127]

[0128] The emulsions prepared in Examples 1-3 and Comparative Examples 1-3 were mixed with an amine curing agent at a weight ratio of 1:0.2. The basic parameters of the curing agent were solid content 40.5%, viscosity 35000 cP, and equivalent weight 350. They were applied to a tinplate substrate and cured into a paint film with a film thickness of 50 μm. The following tests were performed.

[0129] 4. Water and salt spray resistance test

[0130] (1) Immerse in a constant temperature water bath (40°C) for 1 month.

[0131] (2) Neutral salt spray for 600 hours.

[0132]

[0133] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A high-performance water-based epoxy resin emulsion, characterized in that: The method comprises the following raw materials in parts by weight: 40-60 parts of epoxy resin, 2-2.5 parts of emulsifier, 0.5-4 parts of solvent, and 40-60 parts of water; The emulsifier comprises the following raw materials in parts by weight: 100-600 parts of alkanol, 20-250 parts of glycidyl ether epoxy resin, 5-30 parts of alcohol ether and 0.1-3 parts of catalyst; The emulsifier further comprises polyethylene polyamine, and the weight ratio of the polyethylene polyamine to the glycidyl ether epoxy resin is 1-2:100; The preparation method of the emulsifier comprises the following steps: (1) Adding a predetermined amount of alkanol and alcohol ether by weight into a stirring reaction device, introducing an inert gas, raising the temperature to 90-130° C. and maintaining the temperature for at least 1 hour; (2) Maintaining the temperature, adding a predetermined amount of catalyst by weight, and stirring at 180-220 rpm for at least 5 minutes; (3) maintaining the temperature, adding a preset weight portion of glycidyl ether epoxy resin, and stirring at 180-220 rpm for at least 5 hours; (4) Removal of alcohol ethers; (5) Set the temperature to 100°C, stir at 180-220 rpm, add polyethylene polyamine dropwise at a rate of 2-3 g / min, raise the temperature to 120°C after the addition is complete, and react for at least 3 hours; (6) Cooling the mixture to a temperature of ≤90° C., mixing the finished product obtained in step (5) with water in a weight ratio of 1:0.8-1.2, and slowly adding water to the finished product obtained in step (5) to obtain the emulsifier.

2. The aqueous epoxy resin emulsion according to claim 1, characterized in that The average particle size of the waterborne epoxy resin emulsion is 250nm-450nm, and the D100 particle size is less than 800nm.

3. The aqueous epoxy resin emulsion according to claim 1, characterized in that The epoxy resin is bisphenol A epoxy resin.

4. The aqueous epoxy resin emulsion according to claim 3, characterized in that The bisphenol A epoxy resin is one of E51, E44, E20 and E06 or a mixture of more than one of them in any proportion.

5. The aqueous epoxy resin emulsion according to claim 1, characterized in that: The polyethylene polyamine is one of diethylenetriamine, triethylenetetramine and tetraethylenepentamine or a mixture of more than one of them in any proportion.

6. The aqueous epoxy resin emulsion according to claim 1, characterized in that: The catalyst is HBF4 aqueous solution, triphenylphosphine or triphenylphosphine and HBF4 aqueous solution added successively.

7. The method for preparing the waterborne epoxy resin emulsion according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Add the preset weight proportions of epoxy resin and solvent into a reaction stirring device, adjust the temperature to 75-95°C, and then stir at a constant temperature until all dissolved, that is, the mixed material is transparent, and the rotation speed is 50-80 rpm; (2) Adjust the temperature to 85-95°C, keep the temperature constant, add the preset amount of emulsifier by weight, rotate at 200-500 rpm, and stir for at least 20 minutes; (3) adjusting the rotation speed to 1800-2200 rpm, slowly adding a preset amount of water by weight to form a phase inversion, and the mixed material turns into a uniform milky white color, thus preparing the high-performance water-based epoxy resin emulsion.

8. The preparation method according to claim 7, characterized in that: The preparation method of the emulsifier comprises the following steps: (1) Adding a predetermined amount of alkanol and alcohol ether by weight into a stirring reaction device, introducing an inert gas, raising the temperature to 90-130° C. and maintaining the temperature for at least 1 hour; (2) Maintaining the temperature, adding a predetermined amount of catalyst by weight, and stirring at 180-220 rpm for at least 5 minutes; (3) maintaining the temperature, adding a preset weight portion of glycidyl ether epoxy resin, and stirring at 180-220 rpm for at least 5 hours; (4) Removal of alcohol ethers; (5) Set the temperature to 100°C, stir at 180-220 rpm, add polyethylene polyamine dropwise at a rate of 2-3 g / min, raise the temperature to 120°C after the addition is complete, and react for at least 3 hours; (6) Cooling the mixture to a temperature of ≤90° C., mixing the finished product obtained in step (5) with water in a weight ratio of 1:0.8-1.2, and slowly adding water to the finished product obtained in step (5) to obtain the emulsifier.

9. The preparation method according to claim 8, characterized in that: In step (2) of preparing the emulsifier, the specific operation of adding the catalyst is: first add a preset weight portion of triphenylphosphine, stir at 100° C. for at least 5 minutes, then add a preset weight portion of HBF4 aqueous solution, and stir for at least 5 minutes.

10. An application of a high-performance water-based epoxy resin emulsion, characterized in that: The waterborne epoxy resin emulsion according to any one of claims 1 to 6 and the amine curing agent are mixed in a weight ratio of 1:0.1-0.3.

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