Water-borne epoxy resin emulsion and preparation method thereof, paint and coating product

Abstract

The invention relates to a water-borne epoxy resin emulsion, a preparation method thereof, a coating and a coating product. The waterborne epoxy resin emulsion comprises the following raw materials in parts by mass: 60-70 parts of epoxy resin, 2-10 parts of a crosslinking monomer, 8-15 parts of an emulsifier, 15-30 parts of a chain extender, 10-30 parts of an organic solvent and 60-100 parts of water, the crosslinking monomer comprises amine-containing silane, and the chain extender comprises a bisphenol compound. Self-crosslinking can be realized by combining a specific type of crosslinking monomer and a specific type of chain extender with epoxy resin, an emulsifier, an organic solvent and water; amino groups in specific types of cross-linking monomers react with epoxy to enable the cross-linking monomers to be grafted to the main structure of the epoxy resin, phenolic hydroxyl groups in specific types of chain extenders react with epoxy, and the molecular weight of the epoxy resin is effectively increased; silane in the crosslinking monomer is condensed and crosslinked to form a three-dimensional network structure; hydroxyl groups formed after silane is hydrolyzed can enhance the adhesive force between a coating formed by the waterborne epoxy resin emulsion and a metal base material.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a water-based epoxy resin emulsion and a preparation method thereof, a coating and a coating product. Background Art

[0002] As the restrictions on the content of volatile organic compounds (VOC) in coatings become increasingly stringent, the coatings industry is developing in the direction of low pollution and energy saving. Water-based coatings use water as a dispersion medium, which is non-toxic and non-flammable, which is both environmentally friendly and reduces production costs. Epoxy resins have excellent bonding properties and can adhere to metals and non-metallic materials well. They also have a low curing shrinkage rate, generally only 1~2%. Compared with solvent-based and solvent-free polyester resins and alkyd resins, epoxy resins have less VOC volatilization during curing, good product dimensional stability, high hardness after curing, and stable chemical resistance.

[0003] Waterborne epoxy coatings can be divided into two systems: one-component and two-component. Two-component coatings with curing agents can be used in heavy-duty anti-corrosion fields. Compared with two-component epoxy coatings, one-component epoxy coatings have the following advantages: easy construction and application, no construction activation period, no service life, and can greatly expand the application of waterborne epoxy. However, no self-crosslinking waterborne epoxy coatings have been found.

[0004] Therefore, it is necessary to improve the traditional technology. Summary of the invention

[0005] Based on this, the present application provides a self-crosslinkable water-based epoxy resin emulsion and a preparation method thereof, a coating and a coating product.

[0006] The technical solution of this application to solve the above technical problems is as follows.

[0007] The first aspect of the present application provides a water-based epoxy resin emulsion, wherein the raw materials of the water-based epoxy resin emulsion include, by weight:

[0008] 60-70 parts of epoxy resin, 2-10 parts of cross-linking monomer, 8-15 parts of emulsifier, 15-30 parts of chain extender, 10-30 parts of organic solvent and 60-100 parts of water, wherein the cross-linking monomer comprises amine-containing silane, and the chain extender comprises a bisphenol compound.

[0009] In some embodiments, in the waterborne epoxy resin emulsion, the raw materials of the waterborne epoxy resin emulsion include, by weight:

[0010] 60-70 parts of epoxy resin, 3-5 parts of crosslinking monomer, 11-15 parts of emulsifier, 20-28 parts of chain extender, 10-20 parts of organic solvent and 70-90 parts of water.

[0011] In some of the embodiments, in the waterborne epoxy resin emulsion, the amine-containing silane includes at least one of 3-aminopropyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0012] In some of the embodiments, in the waterborne epoxy resin emulsion, the bisphenol compound includes at least one of 4,4'-dihydroxydiphenylmethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 4,4'-(α-methylbenzylidene)bisphenol and 4,4'-dibenzylidenebisphenol.

[0013] In some embodiments, in the waterborne epoxy resin emulsion, the epoxy value of the epoxy resin is 0.50 Eq. / 100g~0.65 Eq. / 100g, and the functionality is 2.0~3.0; and / or

[0014] The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

[0015] In some of the embodiments, in the water-based epoxy resin emulsion, the emulsifier is a water-based epoxy emulsifier; optionally, the emulsifier includes at least one of Reactsurf 0092 and X-405.

[0016] In some of the embodiments, in the aqueous epoxy resin emulsion, the organic solvent includes at least one of an alcohol solvent and an alcohol ether solvent; optionally, the organic solvent includes at least one of ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol phenyl ether, dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol, n-butanol and benzyl alcohol.

[0017] In some of the embodiments, in the water-based epoxy resin emulsion, the raw materials of the water-based epoxy resin emulsion further include 0.05 to 2 parts of a catalyst by mass; optionally, the catalyst is at least one of triphenylphosphine, triphenylethylphosphine bromide, sodium hydroxide, potassium hydroxide, dioctylmethylamine, trioctylamine and octadecyldimethyl tertiary amine.

[0018] In some embodiments, in the waterborne epoxy resin emulsion, the waterborne epoxy resin emulsion satisfies at least one of the following characteristics:

[0019] (1) The solid content of the waterborne epoxy resin emulsion is 40% to 55%;

[0020] (2) The epoxy value of the waterborne epoxy resin emulsion after curing is 0.02 Eq. / 100g~0.2 Eq. / 100g;

[0021] (3) The viscosity of the waterborne epoxy resin emulsion is 500 mPa.s to 8000 mPa.s.

[0022] The second aspect of the present application provides a method for preparing the above-mentioned water-based epoxy resin emulsion, comprising the following steps:

[0023] Mixing the epoxy resin and the cross-linking monomer to perform a first reaction to obtain a first reaction solution;

[0024] Mixing the chain extender with the first reaction solution to perform a second reaction to obtain a second reaction solution;

[0025] An emulsifier, an organic solvent and water are mixed with the second reaction liquid to perform an emulsification treatment.

[0026] In some embodiments, in the method for preparing the waterborne epoxy resin emulsion, the preparation method satisfies at least one of the following characteristics:

[0027] (1) The temperature of the first reaction is 60°C to 80°C, and the reaction time is 2 h to 3 h;

[0028] (2) The temperature of the second reaction is 160°C to 170°C, and the reaction time is 2 h to 3 h;

[0029] (3) The epoxy value of the second reaction liquid is 0.02 Eq. / 100g~0.2 Eq. / 100g.

[0030] The third aspect of the present application provides a coating comprising the above-mentioned water-based epoxy resin emulsion.

[0031] A fourth aspect of the present application provides a coated product, comprising a coating obtained by curing the above-mentioned coating.

[0032] Compared with the prior art, the aqueous epoxy resin emulsion of the present application has the following beneficial effects:

[0033] The water-based epoxy resin emulsion of the present application can achieve self-crosslinking by combining a specific type of cross-linking monomer, a specific type of chain extender with epoxy resin, an emulsifier, an organic solvent and water; the amino group in the specific type of cross-linking monomer reacts with epoxy to graft the cross-linking monomer onto the main structure of the epoxy resin, and the phenolic hydroxyl group in the specific type of chain extender reacts with epoxy to effectively increase the molecular weight of the epoxy resin; the silane in the cross-linking monomer will condense and cross-link itself to form a three-dimensional network structure; the hydroxyl group formed after the hydrolysis of the silane can enhance the adhesion of the coating formed by the water-based epoxy resin emulsion to the metal substrate; the interaction of the components can effectively improve the corrosion resistance of the water-based epoxy resin emulsion, while meeting the requirements of salt spray resistance, water resistance and solvent resistance of the water-based epoxy coating. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below in conjunction with the embodiments and examples. It should be understood that these embodiments and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the understanding of the disclosure of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms, and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present application, and the equivalent form obtained also falls within the protection scope of the present application. For example, the features described or described as part of an embodiment can be combined in another embodiment in a suitable manner to produce a new embodiment. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present application, and it should be understood that the present application can be implemented without one or more of these details.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing implementation modes and embodiments and are not intended to limit this application.

[0036] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0037] In the present application, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a quantity greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0038] As used herein, "combination thereof", "any combination thereof", "any combination thereof" etc. include all suitable combinations of any two or more of the listed items.

[0039] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0040] Herein, "preferred", "better", "more preferred", and "suitable" are only used to describe implementation methods or examples with better effects, and it should be understood that they do not constitute a limitation on the scope of protection of this application. If multiple "preferred" items appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "preferred" item is independent.

[0041] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0042] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0043] In the present application, the terms "first", "second", "third", "fourth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0044] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0045] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0046] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0047] In this application, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0048] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0049] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the invention purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0050] The mass or weight of the relevant components mentioned in the specification of the embodiments of the present application may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the specification of the embodiments of the present application, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass or weight described in the specification of the embodiments of the present application may be units known in the chemical industry such as μg, mg, g, and kg.

[0051] An embodiment of the present application provides a water-based epoxy resin emulsion. The raw materials of the water-based epoxy resin emulsion include, by weight:

[0052] 60-70 parts of epoxy resin, 2-10 parts of cross-linking monomer, 8-15 parts of emulsifier, 15-30 parts of chain extender, 10-30 parts of organic solvent and 60-100 parts of water, the cross-linking monomer includes amine-containing silane, and the chain extender includes bisphenol compound.

[0053] The water-based epoxy resin emulsion of the present application can achieve self-crosslinking by combining a specific type of cross-linking monomer, a specific type of chain extender with epoxy resin, an emulsifier, an organic solvent and water; the amino group in the specific type of cross-linking monomer reacts with epoxy to graft the cross-linking monomer onto the main structure of the epoxy resin, and the phenolic hydroxyl group in the specific type of chain extender reacts with epoxy to effectively increase the molecular weight of the epoxy resin; the silane in the cross-linking monomer will condense and cross-link itself to form a three-dimensional network structure; the hydroxyl group formed after the hydrolysis of the silane can enhance the adhesion of the coating formed by the water-based epoxy resin emulsion to the metal substrate; the interaction of the components can effectively improve the corrosion resistance of the water-based epoxy resin emulsion, while meeting the requirements of salt spray resistance, water resistance and solvent resistance of the water-based epoxy coating.

[0054] It can be understood that, by weight, epoxy resins include but are not limited to 60 parts, 62 parts, 65 parts, 68 parts, and 70 parts; cross-linking monomers include but are not limited to 2 parts, 3 parts, 5 parts, 8 parts, and 10 parts; emulsifiers include but are not limited to 8 parts, 10 parts, 11 parts, 12 parts, and 15 parts; chain extenders include but are not limited to 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, and 30 parts; organic solvents include but are not limited to 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, and 30 parts; water includes but is not limited to 60 parts, 70 parts, 80 parts, 90 parts, and 100 parts; in some examples, any two of these point values ​​can be within the range formed by the end values, the same below.

[0055] In some of the examples, in the waterborne epoxy resin emulsion, the raw materials of the waterborne epoxy resin emulsion include, by weight:

[0056] 60-70 parts of epoxy resin, 3-5 parts of crosslinking monomer, 11-15 parts of emulsifier, 20-28 parts of chain extender, 10-20 parts of organic solvent and 70-90 parts of water.

[0057] It is understood that amine-containing silanes are silanes containing (substituted) amino groups.

[0058] In some of the examples, in the waterborne epoxy resin emulsion, the amine-containing silane includes at least one of 3-aminopropyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0059] In some of the examples, in the waterborne epoxy resin emulsion, the bisphenol compound includes at least one of 4,4'-dihydroxydiphenylmethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 4,4'-(α-methylbenzylidene)bisphenol and 4,4'-dibenzylidenebisphenol.

[0060] In some of these examples, in the waterborne epoxy resin emulsion, the epoxy value of the epoxy resin is 0.50 Eq. / 100g~0.65 Eq. / 100g and the functionality is 2.0~3.0.

[0061] In some of the examples, in the waterborne epoxy resin emulsion, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

[0062] In some of these examples, in the waterborne epoxy resin emulsion, the emulsifier is a waterborne epoxy emulsifier.

[0063] In some of the examples, in the waterborne epoxy resin emulsion, the emulsifier includes at least one of Reactsurf 0092 and X-405.

[0064] In some of the examples, in the waterborne epoxy resin emulsion, the organic solvent includes at least one of an alcohol solvent and an alcohol ether solvent.

[0065] In some of the examples, in the waterborne epoxy resin emulsion, the organic solvent includes at least one of ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol phenyl ether, dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol, n-butanol and benzyl alcohol.

[0066] In some of the examples, in the water-based epoxy resin emulsion, the raw materials of the water-based epoxy resin emulsion also include 0.05 to 2 parts of a catalyst by weight.

[0067] In some of the examples, in the waterborne epoxy resin emulsion, the catalyst is at least one of triphenylphosphine, triphenylethylphosphine bromide, sodium hydroxide, potassium hydroxide, dioctylmethylamine, trioctylamine and octadecyldimethyl tertiary amine.

[0068] In some of these examples, the solid content of the waterborne epoxy resin emulsion is 40%~55%.

[0069] In some of the examples, in the waterborne epoxy resin emulsion, the viscosity of the waterborne epoxy resin emulsion is 500 mPa.s~8000 mPa.s.

[0070] In some of these examples, in the waterborne epoxy resin emulsion, the epoxy value of the waterborne epoxy resin emulsion after curing is 0.02 Eq. / 100g~0.2 Eq. / 100g.

[0071] It will be appreciated that 100 g refers to the mass of the solid.

[0072] In some of the examples, in the waterborne epoxy resin emulsion, the viscosity of the solid after drying of the waterborne epoxy resin emulsion at a temperature of 120°C is 5000 mPa.s~10000 mPa.s.

[0073] An embodiment of the present application provides a method for preparing the above-mentioned water-based epoxy resin emulsion, comprising the following steps:

[0074] The epoxy resin and the cross-linking monomer are mixed to perform a first reaction to obtain a first reaction solution; the cross-linking monomer includes an amine-containing silane;

[0075] Mixing the chain extender with the first reaction liquid for a second reaction to obtain a second reaction liquid; the chain extender includes a bisphenol compound;

[0076] An emulsifier, an organic solvent and water are mixed with the second reaction liquid to perform an emulsification treatment.

[0077] It can be understood that in the first reaction process, the amino groups of the epoxy resin and the cross-linking monomer react; in the second reaction, the phenolic hydroxyl group in the chain extender reacts with the epoxy resin; and in the subsequent curing process of the waterborne epoxy resin emulsion, the silane in the cross-linking monomer will self-condense and cross-link.

[0078] In some of the examples, in the method for preparing the waterborne epoxy resin emulsion, the temperature of the first reaction is 60°C~80°C, and the reaction time is 2 h~3 h.

[0079] In some of the examples, in the method for preparing the waterborne epoxy resin emulsion, the temperature of the second reaction is 160° C. to 170° C., and the reaction time is 2 h to 3 h.

[0080] In some of the examples, in the method for preparing the aqueous epoxy resin emulsion, the epoxy value of the second reaction liquid is 0.02 Eq. / 100g~0.2 Eq. / 100g.

[0081] In some of the examples, in the method for preparing the waterborne epoxy resin emulsion, the second reaction step further includes a step of adding a catalyst.

[0082] In some of the examples, in the preparation method of the water-based epoxy resin emulsion, in the emulsification treatment step, the emulsifier, the organic solvent and the second reaction liquid are first mixed at 110°C~130°C and stirred for 20 min~40 min, then cooled to 70°C~90°C, and water is added dropwise for emulsification.

[0083] In some of these examples, the method for preparing the waterborne epoxy resin emulsion includes the following steps:

[0084] Add epoxy resin into the reactor and heat it to 60℃~80℃, add cross-linking monomer dropwise, react at 60℃~80℃ for 2h~3h, heat it to 160℃~170℃, add chain extender and catalyst, react at 160℃~170℃ for 2h~3h, wait until the epoxy value drops to 0.02 Eq. / 100g~0.2 Eq. / 100g, cool it to 110℃~130℃, add emulsifier and organic solvent, stir at 110℃~130℃ for 20 min~40 min, cool it to 70℃~90℃, add water dropwise for emulsification, keep the temperature at 70℃~90℃, stir for 20 min~40 min after the addition is complete, cool it and discharge the material.

[0085] One embodiment of the present application provides the use of a water-based epoxy resin emulsion in preparing a coating.

[0086] One embodiment of the present application provides a coating, including the above-mentioned water-based epoxy resin emulsion.

[0087] The coating of the present application includes the water-based epoxy resin emulsion provided by the present application, and thus has at least the same advantages as the above-mentioned water-based epoxy resin emulsion.

[0088] One embodiment of the present application provides a coated product, including a coating obtained by curing the above-mentioned coating.

[0089] The coating product provided in this application has good corrosion resistance.

[0090] The present application is further described in detail below in conjunction with specific implementation methods, but the implementation methods of the present application are not limited thereto.

[0091] Example 1

[0092] Add 650 g of E51 epoxy resin to the reactor, heat to 60-80°C, add 50 g of 3-(phenylamino)propyltrimethoxysilane dropwise, react at 60-80°C for 2-3 hours, heat to 160°C, add 200 g of chain extender 4,4'-dihydroxydiphenylmethane and 1 g of triphenylphosphine, react at 160-170°C for 2-3 hours, wait until the epoxy value drops to 0.1-0.3 Eq. / 100 g, cool to 120°C, add 110 g of Reactsurf 0092 and 165 g of propylene glycol methyl ether, stir at 120°C for 30 minutes, cool to 70-90°C, add 820 g of deionized water dropwise for emulsification, add dropwise for 2 hours, keep the temperature at 70-90°C, stir for 30 minutes after the addition is complete, cool and discharge to obtain a waterborne epoxy resin emulsion.

[0093] Example 2

[0094] Add 600g of phenolic epoxy resin 8240 to the reactor, heat to 60-80°C, drop 50g of 3-(phenylamino)propyltrimethoxysilane, react at 60-80°C for 2-3 hours, heat to 160°C, add 260g of chain extender 4,4'-(α-methylbenzylidene)bisphenol and 1g of 0.1mol / L NaOH aqueous solution, react at 160-170°C for 2-3 hours, wait until the epoxy value drops to 0.1-0.2Eq. / 100g, cool to 120°C, add 110g of Reactsurf 0092 and 165g of propylene glycol methyl ether, stir at 120°C for 30 minutes, cool to 70-90°C, add 820g of deionized water for emulsification, add for 2 hours, keep the temperature at 70-90°C, stir for 30 minutes after the addition is completed, cool and discharge to obtain a water-based epoxy resin emulsion.

[0095] Example 3

[0096] Add 700g of bisphenol F E51 epoxy resin to the reactor, heat to 60-80°C, drop 40g of 3-(phenylamino)propyltrimethoxysilane and 15g of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane mixture, react at 60-80°C for 2-3 hours, heat to 160°C, add 280g of chain extender 4,4'-(α-methylbenzylidene)bisphenol and 1g of 0.1mol / L octadecyldimethyl tertiary amine, react at 160-170°C for 2-3 hours, wait until the epoxy value drops to 0.1-0.2Eq. / 100g, cool to 120°C, add 130g of Dow X 405 and 180g of propylene glycol methyl ether, stir at 120°C for 30 minutes, cool to 70-90°C, add 880g of deionized water for emulsification, add for 2 hours, keep the temperature at 70-90°C, stir for 30 minutes after the addition is completed, cool and discharge to obtain a water-based epoxy resin emulsion.

[0097] Comparative Example 1

[0098] The method is substantially the same as Example 1, except that the step of adding the chain extender 4,4'-dihydroxydiphenylmethane is omitted.

[0099] Comparative Example 2

[0100] The method is substantially the same as Example 1, except that the chain extender 4,4'-dihydroxydiphenylmethane is replaced with an equal mass of n-butylamine.

[0101] Comparative Example 3

[0102] The method is substantially the same as Example 1, except that the crosslinking monomer 3-(phenylamino)propyltrimethoxysilane is replaced with an equal amount of 3-glycidyloxypropyltriethoxysilane.

[0103] The epoxy value is measured in accordance with the provisions of GB / T1677-2008; the emulsion viscosity is measured in accordance with the provisions of GB / T21059-2007; the emulsion solid content test is measured in accordance with the provisions of GB / T1725-2007. 3.00g of emulsion is weighed and placed in an aluminum foil tray with a diameter of about 5 cm, which is placed in a forced ventilation oven and baked at 120℃ for several hours until the weight change before and after is less than 0.01g. The solid content of the emulsion is calculated. The results are shown in Table 1.

[0104] Table 1

[0105]

[0106] The waterborne epoxy resin emulsions prepared in Examples 1 to 3 can all achieve self-crosslinking, have good adhesion to metal substrates, have good anti-corrosion properties, and meet the requirements of waterborne epoxy coatings for salt spray resistance, water resistance, and solvent resistance. However, the waterborne epoxy resin emulsions prepared in Comparative Examples 1 to 3 cannot achieve self-crosslinking.

[0107] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A water-based epoxy resin emulsion, characterized in that: The raw materials of the waterborne epoxy resin emulsion include, by mass: 60-70 parts of epoxy resin, 2-10 parts of cross-linking monomer, 8-15 parts of emulsifier, 15-30 parts of chain extender, 10-30 parts of organic solvent and 60-100 parts of water, wherein the cross-linking monomer comprises amine-containing silane, and the chain extender comprises a bisphenol compound.

2. The aqueous epoxy resin emulsion according to claim 1, characterized in that The raw materials of the waterborne epoxy resin emulsion include, by mass: 60-70 parts of epoxy resin, 3-5 parts of crosslinking monomer, 11-15 parts of emulsifier, 20-28 parts of chain extender, 10-20 parts of organic solvent and 70-90 parts of water.

3. The aqueous epoxy resin emulsion according to claim 1, characterized in that The amine-containing silane includes at least one of 3-aminopropyltriethoxysilane, 3-(phenylamino)propyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

4. The aqueous epoxy resin emulsion according to claim 1, characterized in that The bisphenol compound includes at least one of 4,4'-dihydroxydiphenylmethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 4,4'-(α-methylbenzylidene)bisphenol and 4,4'-dibenzylidenebisphenol.

5. The aqueous epoxy resin emulsion according to any one of claims 1 to 4, characterized in that The epoxy resin has an epoxy value of 0.50 Eq. / 100g to 0.65 Eq. / 100g and a functionality of 2.0 to 3.0; and / or The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

6. The aqueous epoxy resin emulsion according to any one of claims 1 to 4, characterized in that The emulsifier is a water-based epoxy emulsifier; optionally, the emulsifier includes at least one of Reactsurf 0092 and X-405.

7. The aqueous epoxy resin emulsion according to any one of claims 1 to 4, characterized in that The organic solvent includes at least one of an alcohol solvent and an alcohol ether solvent; optionally, the organic solvent includes at least one of ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol phenyl ether, dipropylene glycol methyl ether, dipropylene glycol butyl ether, propylene glycol, n-butanol and benzyl alcohol.

8. The aqueous epoxy resin emulsion according to any one of claims 1 to 4, characterized in that The raw materials of the waterborne epoxy resin emulsion also include 0.05 to 2 parts of a catalyst by mass; optionally, the catalyst is at least one of triphenylphosphine, triphenylethylphosphine bromide, sodium hydroxide, potassium hydroxide, dioctylmethylamine, trioctylamine and octadecyldimethyl tertiary amine.

9. The aqueous epoxy resin emulsion according to any one of claims 1 to 4, characterized in that The aqueous epoxy resin emulsion meets at least one of the following characteristics: (1) The solid content of the waterborne epoxy resin emulsion is 40% to 55%; (2) The epoxy value of the waterborne epoxy resin emulsion after curing is 0.02 Eq. / 100g~0.2 Eq. / 100g; (3) The viscosity of the waterborne epoxy resin emulsion is 500 mPa.s to 8000 mPa.s.

10. A method for preparing the aqueous epoxy resin emulsion according to any one of claims 1 to 9, characterized in that: The following steps are involved: Mixing the epoxy resin and the cross-linking monomer to perform a first reaction to obtain a first reaction solution; Mixing the chain extender with the first reaction solution to perform a second reaction to obtain a second reaction solution; An emulsifier, an organic solvent and water are mixed with the second reaction liquid to perform an emulsification treatment.

11. The method for preparing the aqueous epoxy resin emulsion according to claim 10, characterized in that: The preparation method meets at least one of the following characteristics: (1) The temperature of the first reaction is 60°C to 80°C, and the reaction time is 2 h to 3 h; (2) The temperature of the second reaction is 160°C to 170°C, and the reaction time is 2 h to 3 h; (3) The epoxy value of the second reaction liquid is 0.02 Eq. / 100g~0.2 Eq. / 100g.

12. A coating, characterized in that: It comprises the aqueous epoxy resin emulsion as described in any one of claims 1 to 9.

13. A coated product, characterized in that: The invention comprises a coating obtained by curing the coating material as claimed in claim 12.

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