Preparation method of an aqueous acrylic epoxy resin emulsion

Abstract

The present invention discloses a preparation method of an aqueous acrylic epoxy resin emulsion, comprising: reacting a nonionic surfactant with an epoxy resin to generate a nonionic surfactant containing an epoxy structure; mixing a monomer, the nonionic surfactant containing an epoxy structure, and a cosolvent to obtain a first dispersion; the monomer includes styrene and an acrylic monomer; dispersing an anionic surfactant in water to obtain a second dispersion; adding the first dispersion into the second dispersion under stirring conditions, and selectively adding water to disperse and prepare a pre-emulsion; respectively dropping the pre-emulsion and an initiator solution into a reactor under stirring conditions to carry out miniemulsion polymerization reaction of the monomer; the acrylic epoxy resin emulsion prepared by this method has good stability, and the cured electrical properties, adhesion, film state and other properties of the insulating paint prepared therefrom are all good, realizing the organic integration of acrylic resin and epoxy resin into a whole, and being able to make full use of their respective performance advantages.

Description

[0001] This invention is a divisional application of the Chinese invention patent application with application date of December 15, 2020, application number 2020114840607, and name “A water-based acrylic epoxy resin emulsion, its preparation method and application”. Technical Field

[0002] The invention belongs to the technical field of water-based surface paints, and particularly relates to a method for preparing a water-based acrylic epoxy resin emulsion. Background Art

[0003] Insulating varnish is mainly used for coils and other insulating parts of motors and electrical appliances to fill their gaps. After curing, the impregnated object becomes a dense whole, thereby improving its insulation performance, mechanical properties and weather resistance. Insulating varnish is generally divided into two types: solvent varnish and solvent-free varnish. However, the solvent varnish and solvent-free varnish currently on the market contain certain volatile harmful substances, which are harmful to people and the environment, and are flammable and explosive, and there are safety hazards in transportation and storage.

[0004] Water-based insulating paint uses water as a diluent. It has low overall cost, low toxicity, safe use and storage, excellent dielectric properties, easy use, good permeability, and high bonding strength. It is the first choice for insulating paint in the future. Epoxy resin has high strength, strong bonding force, and good electrical properties. It is an excellent insulating material, but it has poor weather resistance and is easy to age; acrylic resin has good weather resistance, but its electrical properties are average. Combining the two organically is a way to prepare insulating paint with excellent comprehensive performance. However, if the two resins are directly mixed, they will produce serious phase separation after curing, and the electrical properties will be greatly reduced. Therefore, how to organically combine the two becomes a problem that must be solved.

[0005] There are two main methods for combining the two. One is to react epoxy resin with acrylic monomer first to generate epoxy ester, and then conduct emulsion polymerization to introduce epoxy resin into acrylic polymer. However, this method destroys the epoxy group and changes the original excellent properties of epoxy resin. The other is to pre-mix epoxy resin and acrylic monomer, and then add emulsifier for emulsion polymerization. Although this method retains the characteristics of epoxy resin, the mixing amount of epoxy resin in this method is relatively low, which can only reach about 10%. If it exceeds 10%, a large amount of epoxy resin will precipitate from the emulsion, and the stability is not good. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an improved method for preparing an acrylic epoxy resin emulsion. The acrylic epoxy resin emulsion prepared by the method has good stability, and the electrical properties, adhesion and paint film state of the insulating paint prepared after curing are all good. The acrylic resin and the epoxy resin are organically integrated into a whole, and their respective performance advantages can be fully utilized.

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

[0008] A method for preparing a water-based acrylic epoxy resin emulsion, the preparation method comprising the following steps:

[0009] (1) reacting a nonionic surfactant with an epoxy resin to generate a nonionic surfactant containing an epoxy structure, wherein the nonionic surfactant is polyoxyethylene sorbitan fatty acid ester and / or castor oil polyoxyethylene ether;

[0010] (2) mixing an acrylic acid monomer, the epoxy structure-containing nonionic surfactant and a cosolvent to obtain a first dispersion;

[0011] dispersing an anionic surfactant in water to obtain a second dispersion;

[0012] adding the first dispersion to the second dispersion under stirring conditions, and optionally adding water to disperse to form a pre-emulsion;

[0013] (3) respectively dropping the pre-emulsion and the initiator solution into a reactor under stirring conditions to carry out a mini-emulsion polymerization reaction of the acrylic acid monomer; wherein the initiator solution is prepared by dispersing the initiator in water.

[0014] According to some preferred aspects of the present invention, in step (1), the mass ratio of the nonionic surfactant to the epoxy resin is 1:10-20.

[0015] According to some preferred aspects of the present invention, in step (1), the reaction is carried out at 160-220° C. Further preferably, in step (1), the reaction is carried out at 180-200° C.

[0016] According to some preferred aspects of the present invention, in step (1), the method for preparing the non-ionic surfactant containing an epoxy structure comprises the following steps: heating a portion of the epoxy resin to 160-220° C., adding the non-ionic surfactant, reacting, and then adding the remaining epoxy resin, reacting to generate the non-ionic surfactant containing an epoxy structure.

[0017] According to some preferred aspects of the present invention, in step (1), the polyoxyethylene sorbitan fatty acid ester is a combination of one or more selected from Tween-20, Tween-60 and Tween-80, and the castor oil polyoxyethylene ether is a combination of one or more selected from EL-20, EL-40, EL-60 and EL-90.

[0018] According to some preferred aspects of the present invention, in step (1), the epoxy resin is selected from bisphenol A type solid epoxy resin having an epoxy equivalent greater than or equal to 500. Further, in step (1), the bisphenol A type solid epoxy resin can be E20 bisphenol A type epoxy resin, E12 bisphenol A type epoxy resin, E06 bisphenol A type epoxy resin, E03 bisphenol A type epoxy resin, and the like.

[0019] According to some preferred aspects of the present invention, in step (1), the nonionic surfactant is composed of polyoxyethylene sorbitan fatty acid ester and castor oil polyoxyethylene ether, and the mass ratio of the two is 0.1-2:1, preferably 0.3-1.5:1.

[0020] According to some preferred aspects of the present invention, in step (2), the feed mass ratio of the epoxy structure-containing nonionic surfactant to the acrylic acid monomer is 1:0.25-4.

[0021] According to some preferred aspects of the present invention, in step (2), the mixing of the acrylic monomer, the epoxy structure-containing nonionic surfactant and the co-solvent is controlled to be carried out at a temperature below 60°C.

[0022] According to some specific and preferred aspects of the present invention, in step (2), the acrylic monomer is a combination of one or more selected from styrene, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, octalactone acrylate, hydroxypropyl acrylate, hydroxyethyl acrylate, methyl methacrylate, butyl methacrylate and hydroxypropyl methacrylate.

[0023] According to some specific and preferred aspects of the present invention, in step (2), the co-solvent is one or more selected from alcohol ester dodecaned, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, diethylene glycol propyl ether, propylene glycol butyl ether and propylene glycol methyl ether acetate.

[0024] According to some specific and preferred aspects of the present invention, in step (2), the concentration of the anionic surfactant in the second dispersion is 0.5-10%, and the anionic surfactant is a fatty alcohol / nonylphenol polyoxyethylene ether sulfate and / or a fatty alcohol / nonylphenol polyoxyethylene ether phosphate. Further, the anionic surfactant can be fatty alcohol / nonylphenol polyoxyethylene ether (3-24) sodium sulfate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) sodium phosphate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) potassium sulfate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) potassium phosphate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) ammonium sulfate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) ammonium phosphate, etc.

[0025] According to some preferred aspects of the present invention, the specific implementation method of step (3) is: adding water to the reactor, heating it to 80-85°C, then dripping the pre-emulsion and the initiator solution into the reactor respectively, and controlling the reaction temperature during the dripping process to always be 80-85°C; after the dripping is completed, heating it to 90-95°C and reacting.

[0026] According to some preferred aspects of the present invention, in a specific implementation of step (3), the dropping speeds of the pre-emulsion and the initiator solution are controlled, and the dropping time is controlled to be 2.5-3h respectively.

[0027] According to some specific aspects of the present invention, in step (3), the initiator is ammonium persulfate and / or potassium persulfate.

[0028] According to some specific aspects of the present invention, the preparation method further comprises step (4): cooling the material obtained after the reaction in step (3), filtering, and obtaining the water-based acrylic epoxy resin emulsion. Furthermore, the cooling in step (4) is cooling to below 45°C.

[0029] According to some preferred aspects of the present invention, the water used in the preparation method of the present invention is deionized water.

[0030] According to some preferred aspects of the present invention, in step (3), the initiator solution can be partially prepared in advance and then partially prepared during the dropwise addition process, and prepared in batches as much as possible, so as to maintain the activity of the initiator.

[0031] Another technical solution provided by the present invention is a water-based acrylic epoxy resin emulsion prepared by the above-mentioned preparation method.

[0032] The present invention also provides an application of the water-based acrylic epoxy resin emulsion prepared by the preparation method in water-based insulating paint.

[0033] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0034] In the preparation process of the acrylic epoxy resin emulsion of the present invention, a specific nonionic surfactant is innovatively used to carry out graft modification with the epoxy resin, thereby obtaining a nonionic surfactant containing an epoxy structure, which can be used as an epoxy resin emulsifier with surface activity, and then the emulsifier can be used as a nonionic surfactant to participate in the subsequent mini-emulsion polymerization, and at the same time, the anionic surfactant can be used to better cooperate, thereby avoiding the problem of precipitation of epoxy resin in the mini-emulsion polymerization process caused by the addition of an emulsifier in the epoxy resin with high content or high epoxy equivalent, so that the stability of the prepared acrylic epoxy resin emulsion is greatly improved, and the electrical properties, adhesion and paint film state of the prepared insulating paint after curing are all good, thereby achieving overall performance improvement. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with specific examples. It should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited by the following examples. The implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the unspecified implementation conditions are generally the conditions in routine experiments. The raw materials used in the examples are all commercially available industrial products.

[0036] In the following examples, unless otherwise specified, all raw materials are basically purchased from commercial sources or prepared by conventional methods in the art. In the following examples, E20 bisphenol A epoxy resin was purchased from Nantong Xingchen; E12 bisphenol A epoxy resin was purchased from Nantong Xingchen; E03 bisphenol A epoxy resin was purchased from Nantong Xingchen; Tween-80 was purchased from Zhejiang Huangma Chemical, Tween-20 was purchased from Zhejiang Huangma Chemical, castor oil polyoxyethylene ether EL40, 60, 80, 90 were all purchased from Jiangsu Haian Petrochemical; fatty alcohol polyoxyethylene ether (10) potassium phosphate, nonylphenol polyoxyethylene ether (10) potassium phosphate were all purchased from Jiangsu Haian Petrochemical, and acrylic acid monomers were all purchased from Beijing Anxingtai Chemical Co., Ltd.

[0037] Example 1

[0038] This example provides a water-based acrylic epoxy resin emulsion, whose raw materials include: 20 kg E12 bisphenol A epoxy resin, 30 kg E20 bisphenol A epoxy resin, 15 kg styrene, 20 kg methyl methacrylate, 10 kg butyl methacrylate, 5 kg hydroxypropyl methacrylate, 2 kg Tween-80, 2 kg castor oil polyoxyethylene ether EL-40, 4 kg fatty alcohol polyoxyethylene ether (10) potassium phosphate (active ingredient 50%), 15 kg diethylene glycol butyl ether, and 0.5 kg potassium persulfate.

[0039] The preparation method of the water-based acrylic epoxy resin emulsion comprises the following steps:

[0040] (1) Preparation of nonionic surfactants containing epoxy structures:

[0041] Heat and melt 5 kg of E12 epoxy resin and 10 kg of E20 epoxy resin, and raise the temperature to 190°C, then add 2 kg of Tween-80 and 2 kg of castor oil polyoxyethylene ether EL-40, and stir evenly; keep the system temperature at 190±5°C for 60 minutes, then add the remaining epoxy resin, and continue to react for 60 minutes to obtain a nonionic surfactant containing an epoxy structure;

[0042] (2) Preparation of pre-emulsion:

[0043] Mix all acrylic monomers: 15 kg styrene, 20 kg methyl methacrylate, 10 kg butyl methacrylate, and 5 kg hydroxypropyl methacrylate and stir evenly;

[0044] Slowly add the epoxy structure-containing nonionic surfactant to the acrylic acid monomer, control the addition speed so that the system temperature is maintained below 60° C., add 15 kg of diethylene glycol butyl ether after the addition, and stir evenly to obtain a first dispersion;

[0045] Dissolve 4 kg of fatty alcohol polyoxyethylene ether (10) potassium phosphate in 40 kg of water and stir to completely dissolve it to obtain a second dispersion;

[0046] Slowly add the first dispersion into the second dispersion, keep stirring at high speed during the addition process, continue stirring for 60 minutes after the addition is completed, and then slowly add 60 kg of water to dilute to obtain a pre-emulsion;

[0047] (3) Preparation of water-based acrylic epoxy resin emulsion:

[0048] 110 kg of deionized water is added to a reactor with a stirrer and heated to 82±2°C. The pre-emulsion and the initiator solution are dripped into the reactor with a dropping funnel, the stirring speed is controlled to be 100±10rpm / min, and the reaction temperature is controlled at 82±2°C by cooling water; the dripping speed is controlled to make the pre-emulsion and the initiator solution dripped in 3 hours respectively, and after the dripping is completed, the temperature is raised to 92±2°C and the reaction is continued for 1 hour; wherein, the initiator solution is prepared in the following manner: dispersed in water, firstly 2 kg of 5% potassium persulfate solution is prepared, and when it is almost finished, 2 kg of 5% solution is prepared, and the preparation is divided into 5 batches, and the purpose of batch preparation is to maintain the activity of the initiator;

[0049] (4) Cooling water is passed through the material to reduce the material temperature to below 45°C, and the material is filtered through a 200-mesh filter bag to obtain a water-based acrylic epoxy resin emulsion.

[0050] Example 2

[0051] This example provides a water-based acrylic epoxy resin emulsion, whose raw materials include: 10 kg E03 bisphenol A epoxy resin, 10 kg E12 bisphenol A epoxy resin, 30 kg E20 bisphenol A epoxy resin, 25 kg styrene, 10 kg methyl methacrylate, 10 kg butyl methacrylate, 4 kg hydroxypropyl methacrylate, 1 kg methacrylic acid, 2 kg Tween-20, 2 kg castor oil polyoxyethylene ether EL-80, 4 kg fatty alcohol polyoxyethylene ether (10) potassium phosphate (active ingredient 50%), 18 kg dipropylene glycol propyl ether, and 0.5 kg potassium persulfate.

[0052] The preparation method of the water-based acrylic epoxy resin emulsion comprises the following steps:

[0053] (1) Preparation of nonionic surfactants containing epoxy structures:

[0054] Heat and melt 2.5 kg of E03 epoxy resin, 2.5 kg of E12 epoxy resin and 10 kg of E20 epoxy resin, and raise the temperature to 190°C, then add 2 kg of Tween-20 and 2 kg of castor oil polyoxyethylene ether EL-80, and stir evenly; keep the system temperature at 190±5°C for 60 minutes, then add the remaining epoxy resin, and continue to react for 60 minutes to obtain a non-ionic surfactant containing an epoxy structure;

[0055] (2) Preparation of pre-emulsion:

[0056] Mix 25 kg of styrene, 10 kg of methyl methacrylate, 10 kg of butyl methacrylate, 4 kg of hydroxypropyl methacrylate and 1 kg of methacrylic acid and stir evenly;

[0057] Slowly add the epoxy structure-containing nonionic surfactant to the acrylic acid monomer, control the addition speed so that the system temperature is maintained below 60° C., add 18 kg of dipropylene glycol propyl ether after the addition is complete, and stir evenly to obtain a first dispersion;

[0058] Dissolve 4 kg of fatty alcohol polyoxyethylene ether (10) potassium phosphate in 40 kg of water and stir to completely dissolve it to obtain a second dispersion;

[0059] Slowly add the first dispersion into the second dispersion, keep stirring at high speed during the addition process, continue stirring for 60 minutes after the addition is completed, and then slowly add 60 kg of water to dilute to obtain a pre-emulsion;

[0060] (3) Preparation of water-based acrylic epoxy resin emulsion:

[0061] 110 kg of deionized water is added to a reactor with a stirrer and heated to 82±2°C. The pre-emulsion and the initiator solution are dripped into the reactor with a dropping funnel, the stirring speed is controlled to be 100±10rpm / min, and the reaction temperature is controlled at 82±2°C by cooling water; the dripping speed is controlled to make the pre-emulsion and the initiator solution dripped in 3 hours respectively, and after the dripping is completed, the temperature is raised to 92±2°C and the reaction is continued for 1 hour; wherein, the initiator solution is prepared in the following manner: dispersed in water, firstly 2 kg of 5% potassium persulfate solution is prepared, and when it is almost finished, 2 kg of 5% solution is prepared, and the preparation is divided into 5 batches, and the purpose of batch preparation is to maintain the activity of the initiator;

[0062] (4) Cooling water is passed through the material to reduce the material temperature to below 45°C, and the material is filtered through a 200-mesh filter bag to obtain a water-based acrylic epoxy resin emulsion.

[0063] Example 3

[0064] This example provides a water-based acrylic epoxy resin emulsion, whose raw materials include: 15 kg E03 bisphenol A epoxy resin, 15 kg E12 bisphenol A epoxy resin, 40 kg E20 bisphenol A epoxy resin, 10 kg styrene, 10 kg methyl methacrylate, 8 kg butyl methacrylate, 1.5 kg hydroxypropyl methacrylate, 0.5 kg methacrylic acid, 3 kg Tween-20, 4 kg castor oil polyoxyethylene ether EL-60, 2 kg fatty alcohol polyoxyethylene ether (10) potassium phosphate (active ingredient 50%), 25 kg dipropylene glycol propyl ether, and 0.5 kg potassium persulfate.

[0065] The preparation method of the water-based acrylic epoxy resin emulsion comprises the following steps:

[0066] (1) Preparation of nonionic surfactants containing epoxy structures:

[0067] Heat and melt 5 kg of E03 epoxy resin, 5 kg of E12 epoxy resin and 20 kg of E20 epoxy resin, and raise the temperature to 190°C, then add 3 kg of Tween-20 and 4 kg of castor oil polyoxyethylene ether EL-60, and stir evenly; keep the system temperature at 190±5°C for 60 minutes, then add the remaining epoxy resin and continue to react for 60 minutes to obtain a nonionic surfactant containing an epoxy structure;

[0068] (2) Preparation of pre-emulsion:

[0069] 10 kg of styrene, 10 kg of methyl methacrylate, 8 kg of butyl methacrylate, 1.5 kg of hydroxypropyl methacrylate, and 0.5 kg of methacrylic acid were mixed and stirred evenly;

[0070] Slowly add the epoxy structure-containing nonionic surfactant to the acrylic acid monomer, control the addition speed so that the system temperature is maintained below 60° C., add 25 kg of dipropylene glycol propyl ether after the addition is complete, and stir evenly to obtain a first dispersion;

[0071] Dissolve 2 kg of fatty alcohol polyoxyethylene ether (10) potassium phosphate in 60 kg of water and stir to completely dissolve it to obtain a second dispersion;

[0072] Slowly add the first dispersion into the second dispersion, keep stirring at high speed during the addition process, continue stirring for 60 minutes after the addition is completed, and then slowly add 60 kg of water to dilute to obtain a pre-emulsion;

[0073] (3) Preparation of water-based acrylic epoxy resin emulsion:

[0074] 110 kg of deionized water is added to a reactor with a stirrer and heated to 82±2°C. The pre-emulsion and the initiator solution are dripped into the reactor with a dropping funnel, the stirring speed is controlled to be 100±10rpm / min, and the reaction temperature is controlled at 82±2°C by cooling water; the dripping speed is controlled to make the pre-emulsion and the initiator solution dripped in 3 hours respectively, and after the dripping is completed, the temperature is raised to 92±2°C and the reaction is continued for 1 hour; wherein, the initiator solution is prepared in the following manner: dispersed in water, firstly 2 kg of 5% potassium persulfate solution is prepared, and when it is almost finished, 2 kg of 5% solution is prepared, and the preparation is divided into 5 batches, and the purpose of batch preparation is to maintain the activity of the initiator;

[0075] (4) Cooling water is passed through the material to reduce the material temperature to below 45°C, and the material is filtered through a 200-mesh filter bag to obtain a water-based acrylic epoxy resin emulsion.

[0076] Example 4

[0077] The present example provides a water-based acrylic epoxy resin emulsion, whose raw materials include: 5 kg E03 bisphenol A epoxy resin, 5 kg E12 bisphenol A epoxy resin, 20 kg E20 bisphenol A epoxy resin, 30 kg styrene, 20 kg methyl methacrylate, 15 kg butyl methacrylate, 4 kg hydroxypropyl methacrylate, 1 kg methacrylic acid, 1 kg Tween-80, 2 kg castor oil polyoxyethylene ether EL-80, 6 kg nonylphenol polyoxyethylene ether (10) potassium phosphate (active ingredient 50%), 10 kg dipropylene glycol propyl ether, and 0.6 kg potassium persulfate.

[0078] The preparation method of the water-based acrylic epoxy resin emulsion comprises the following steps:

[0079] (1) Preparation of nonionic surfactants containing epoxy structures:

[0080] Heat and melt 2.5 kg of E03 epoxy resin, 2.5 kg of E12 epoxy resin and 10 kg of E20 epoxy resin, and raise the temperature to 190°C, then add 3 kg of 1 kg of Tween-80 and 2 kg of castor oil polyoxyethylene ether EL-80, and stir evenly; keep the system temperature at 190±5°C for 60 minutes, then add the remaining epoxy resin and continue to react for 60 minutes to obtain a non-ionic surfactant containing an epoxy structure;

[0081] (2) Preparation of pre-emulsion:

[0082] 30 kg of styrene, 20 kg of methyl methacrylate, 15 kg of butyl methacrylate, 4 kg of hydroxypropyl methacrylate and 1 kg of methacrylic acid were mixed and stirred evenly;

[0083] Slowly add the epoxy structure-containing nonionic surfactant to the acrylic acid monomer, control the addition speed so that the system temperature is maintained below 60° C., add 10 kg of dipropylene glycol propyl ether after the addition is complete, and stir evenly to obtain a first dispersion;

[0084] Dissolve 6 kg of nonylphenol polyoxyethylene ether (10) potassium phosphate in 100 kg of water and stir to completely dissolve it to obtain a second dispersion;

[0085] Slowly add the first dispersion into the second dispersion, keep stirring at high speed during the addition process, continue stirring for 60 minutes after the addition is completed, and then slowly add 60 kg of water to dilute to obtain a pre-emulsion;

[0086] (3) Preparation of water-based acrylic epoxy resin emulsion:

[0087] 80 kg of deionized water was added to a reactor with a stirrer and heated to 82±2°C. The pre-emulsion and the initiator solution were dripped into the reactor using a dropping funnel, the stirring speed was controlled to be 100±10rpm / min, and the reaction temperature was controlled at 82±2°C by passing cooling water. The dripping speed was controlled to ensure that the pre-emulsion and the initiator solution were dripped in 3 hours respectively. After the dripping was completed, the temperature was raised to 92±2°C and the reaction was continued for 1 hour. The initiator solution was prepared as follows: 2 kg of 5% potassium persulfate solution was prepared by water dispersion, and when the solution was about to be dripped, 2 kg of 5% solution was prepared. The solution was prepared in 6 batches. The purpose of preparing the solution in batches was to maintain the activity of the initiator.

[0088] (4) Cooling water is passed through the material to reduce the material temperature to below 45°C, and the material is filtered through a 200-mesh filter bag to obtain a water-based acrylic epoxy resin emulsion.

[0089] Comparative Example

[0090] The method is basically the same as Example 1, except that "2 kg Tween-80, 2 kg castor oil polyoxyethylene ether EL-40" are replaced with 4 kg of commercially available alkylphenol polyoxyethylene ether (16) (purchased from Zhejiang Huangma Chemical, brand HMNP-16).

[0091] Performance Testing

[0092] The emulsions prepared in the above Examples 1-4 and Comparative Examples were subjected to the following performance tests. The specific results are shown in Tables 1 and 2.

[0093] Table 1 Emulsion performance test

[0094]

[0095] Description of the test method:

[0096] 1. Stable storage at room temperature: After 120 days of storage at room temperature, if there is no precipitation or stratification, or there is only a small amount of precipitation or stratification, but it can be evenly dispersed again with slight stirring, it is considered to have passed the stability test, otherwise it has failed.

[0097] 2. Storage stability at 40℃: Store in an oven at 40℃ for 30 days. If there is no precipitation or stratification at all, or there is only a small amount of precipitation or stratification, but it can be evenly dispersed again with slight stirring, it is considered to have passed the stability test, otherwise it has failed.

[0098] 3. Centrifugal stability: Centrifuge at 3000r / min for 30min. If there is no precipitation or stratification at all, or there is only a small amount of precipitation or stratification, but it can be evenly dispersed again with slight stirring, it is considered to have passed the stability test, otherwise it has failed.

[0099] 4. Calcium ion stability (GB / T 20623-2006): Add 0.5g calcium chloride to 100g distilled water, then add 25g emulsion, shake well and let stand for 24 hours. If there is no demulsification, stratification or gelation, the stability is passed.

[0100] 5. Freeze-thaw stability (GB / T 20623-2006): Freeze at -15°C for 16 hours, then thaw at room temperature for 8 hours, repeat five times, if there is no emulsion breaking, it is considered to have passed the stability test.

[0101] 6. Pigment and filler mixing stability: Grind the emulsion and common pigments and fillers in a sand mill. If the emulsion does not break, it is considered to have passed the stability test.

[0102] Table 2 Performance test after curing

[0103]

[0104] Curing method and performance index description of cured products

[0105] The curing agent is a composition of amino resin and DMP-30 (2,4,6-tris(dimethylaminomethyl)phenol), wherein the amount of amino resin is 10% of the amount of emulsion resin and the amount of DMP-30 is 20% of the amount of amino resin.

[0106] The amino resin and DPM-30 were mixed with the emulsion, and stirred evenly, and 0.1% of defoaming agent (specifically: Datian Chemical AT-720B) was added.

[0107] The copper sheet was immersed in the emulsion for 30 seconds, and then taken out and baked in an oven at 130°C for 3 hours to observe the state of the paint film, detect the volume resistance (the national test standard is GB / T 1981.2-2009), and the breakdown strength (the national test standard is GB / T1981.2-2009).

[0108] The spiral coil was immersed in the emulsion for 30 seconds, and then taken out and placed in an oven at 130°C for 3 hours to test the adhesion of the resin (the national standard for the test is GB / T1981.2-2009).

[0109] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a water-based acrylic epoxy resin emulsion, It is characterized in that The preparation method comprises the following steps: (1) reacting a nonionic surfactant with an epoxy resin at 160-220° C. to generate a nonionic surfactant containing an epoxy structure; wherein the nonionic surfactant is composed of polyoxyethylene sorbitan fatty acid ester and castor oil polyoxyethylene ether, the mass ratio of the polyoxyethylene sorbitan fatty acid ester to the castor oil polyoxyethylene ether is 0.1-2:1, the epoxy resin is a bisphenol A type solid epoxy resin with an epoxy equivalent of greater than or equal to 500, and the mass ratio of the nonionic surfactant to the epoxy resin is 1:10-20; (2) mixing the monomer, the epoxy structure-containing nonionic surfactant and the cosolvent to obtain a first dispersion; The monomer is composed of styrene and one or more selected from acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, octalactone acrylate, hydroxypropyl acrylate, hydroxyethyl acrylate, methyl methacrylate, butyl methacrylate and hydroxypropyl methacrylate; dispersing an anionic surfactant in water to obtain a second dispersion; adding the first dispersion into the second dispersion under stirring conditions, and optionally adding water to disperse and prepare a pre-emulsion; (3) respectively dropping the pre-emulsion and the initiator solution into a reactor under stirring conditions to carry out a mini-emulsion polymerization reaction of the monomer; wherein the initiator solution is prepared by dispersing the initiator in water.

2. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that In step (1), the epoxy resin is E20 bisphenol A epoxy resin, E12 bisphenol A epoxy resin, E06 bisphenol A epoxy resin or E03 bisphenol A epoxy resin, the polyoxyethylene sorbitan fatty acid ester is a combination of one or more selected from Tween-20, Tween-60 and Tween-80, and the castor oil polyoxyethylene ether is a combination of one or more selected from EL-20, EL-40, EL-60 and EL-90.

3. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that In step (1), the preparation method of the nonionic surfactant containing an epoxy structure comprises the following steps: heating a portion of the epoxy resin to 160-220° C., adding the nonionic surfactant, reacting, and then adding the remaining epoxy resin, reacting to generate the nonionic surfactant containing an epoxy structure.

4. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1 or 3, It is characterized in that In step (1), the reaction is carried out at 180-200° C., and the mass ratio of the polyoxyethylene sorbitan fatty acid ester to the castor oil polyoxyethylene ether is 0.3-1.5:

1.

5. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that In step (2), the feed mass ratio of the epoxy structure-containing nonionic surfactant to the monomer is 1:0.25-4.

6. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that In step (2), the mixing of the monomer, the nonionic surfactant containing an epoxy structure and the cosolvent is controlled to be carried out at a temperature below 60° C., and the cosolvent is one or more selected from the group consisting of alcohol ester dodecaned, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, diethylene glycol propyl ether, propylene glycol butyl ether and propylene glycol methyl ether acetate.

7. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that In step (2), the concentration of the anionic surfactant in the second dispersion is 0.5%-10%, and the anionic surfactant is fatty alcohol / nonylphenol polyoxyethylene ether sulfate and / or fatty alcohol / nonylphenol polyoxyethylene ether phosphate.

8. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 7, It is characterized in that The anionic surfactant is fatty alcohol / nonylphenol polyoxyethylene ether (3-24) sodium sulfate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) sodium phosphate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) potassium sulfate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) potassium phosphate, fatty alcohol / nonylphenol polyoxyethylene ether (3-24) ammonium sulfate or fatty alcohol / nonylphenol polyoxyethylene ether (3-24) ammonium phosphate.

9. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that The specific implementation method of the step (3) is as follows: add water to the reactor, heat it to 80-85°C, then drop the pre-emulsion and the initiator solution into the reactor respectively, and control the reaction temperature during the dropwise addition process to always be 80-85°C; after the dropwise addition is completed, heat it to 90-95°C and react; wherein the dropwise addition time of the pre-emulsion and the initiator solution is controlled to be 2.5-3h respectively.

10. The method for preparing the aqueous acrylic epoxy resin emulsion according to claim 1, It is characterized in that The water is deionized water; The initiator is potassium persulfate, and the initiator solution is prepared in batches, with a portion prepared in advance and another portion prepared during the dropwise addition process.

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