A temporary protective waterborne coating, coating layer, preparation method and application

Abstract

The application provides a preparation method of temporary protective water-based paint and relates to the technical field of high polymer protective coating. The method comprises the following steps: under the action of an initiator and an accelerator, water-based unsaturated polyester and acrylic monomers are subjected to a polymerization reaction in a protective atmosphere to obtain a polyester-acrylate hybrid solution; under the stirring of an environment at 45-55 DEG C, a hydrolysis catalyst is added to the polyester-acrylate hybrid solution, and the temporary protective water-based paint is prepared after cooling to room temperature; wherein the hydrolysis catalyst is used for hydrolyzing ester groups and forming carboxylic acid groups. The water-based unsaturated polyester-acrylic resin emulsion prepared by the method has small particle size, concentrated distribution, high conversion rate, excellent scratch resistance and water solubility after film formation, is suitable for temporary protection during the installation process of various materials, and can be removed by using water at 20 DEG C or above after completing the temporary protection.

Description

Technical Field

[0001] This invention relates to the field of polymer protective coating technology, and in particular to a temporary protective water-based coating, its preparation method, and its application. Background Technology

[0002] Engineering materials can be categorized into structural materials and functional materials based on their performance characteristics. Structural materials primarily possess mechanical properties such as hardness, strength, plasticity, and impact toughness, while also exhibiting certain physical and chemical properties. Functional materials, on the other hand, are functional and effect materials primarily characterized by special physical and chemical properties such as optical, electrical, acoustic, magnetic, and thermal properties. Engineering materials occupy a prominent position in the development of manufacturing and industry, and their performance and stability directly affect the safety and durability during use.

[0003] For example, in the nuclear energy industry, during the installation and operation of nuclear fuel rods in nuclear reactors, their surfaces are highly susceptible to external environmental influences and operating equipment, leading to scratches or damage. These scratches and damage not only affect the service life of the nuclear fuel rods but may also impact the overall safety of the nuclear reactor. Therefore, temporary protective measures are particularly important during the installation and operation of nuclear fuel rods. By applying temporary protective coatings to the surface of nuclear fuel rods, scratches can be effectively reduced, ensuring the integrity and safety of the nuclear fuel rods. Furthermore, many other materials also require temporary protection during manufacturing and use. For example, metal parts are susceptible to oxidation, corrosion, and mechanical damage during processing, transportation, and installation. Wood is also susceptible to moisture, insect infestation, and mechanical damage during processing and use. Applying temporary protective coatings to the surfaces of these materials can effectively improve their durability and service life. Temporary protective coatings not only need to provide good protection during use but also need to be easily removed after use, leaving no residue and avoiding permanent damage to the material surface. Therefore, developing a high-performance, easy-to-remove temporary protective water-based coating is of great significance and has broad application prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a temporary protective water-based coating, its preparation method, and its application. By grafting polymerization, acrylic monomers are used to modify unsaturated polyesters, thereby introducing ester groups. The ester groups are then hydrolyzed using a hydrolysis catalyst to form carboxylic acid groups, which can significantly improve the water solubility of the coating after it is formed.

[0005] In a first aspect, the present invention provides a method for preparing a temporary protective water-based coating, comprising the following steps: in a protective atmosphere, under the action of an initiator and a accelerator, a water-based unsaturated polyester and an acrylic monomer undergo a polymerization reaction to obtain a polyester acrylate hybrid solution; under a stirring environment at 45-55°C, a hydrolysis catalyst is added to the polyester acrylate hybrid solution, and after cooling to room temperature, a temporary protective water-based coating is obtained; wherein, the hydrolysis catalyst is used to hydrolyze ester groups to form carboxylic acid groups.

[0006] The preparation method provided by this invention enables the polyester double bond to undergo an addition reaction with the acrylic monomer double bond under the action of an initiator and an accelerator. The resulting polyester acrylate hybrid can be cured at 40-50℃ to form a coating with a hardness of 2-3H. Furthermore, by using a hydrolysis catalyst to hydrolyze the ester group in the polyester acrylate hybrid into a carboxylic acid group, the hydrophilicity of the polyester acrylate hybrid can be significantly improved, which is beneficial to improving the water solubility and ease of removing the coating.

[0007] Optionally, the process of preparing the polyester acrylate hybrid solution includes: mixing acrylic monomers with an initiator to obtain a first mixture and a second mixture; adding the first mixture to an aqueous unsaturated polyester and stirring to react, then adding the second mixture and mixing, and adding an accelerator dropwise while stirring to mix, adjusting the acid value and pH to obtain the polyester acrylate hybrid solution. This is beneficial for the polymerization reaction of acrylic monomers and aqueous unsaturated polyester.

[0008] Optionally, after mixing the acrylic monomer and the initiator to obtain the first mixture, the mass mixing ratio of the acrylic monomer and the initiator in the first mixture is (5-15):(0.025-0.45).

[0009] Optionally, during the process of adding the first mixture to the water-based unsaturated polyester and stirring, the mass mixing ratio of the acrylic monomer in the first mixture to the water-based unsaturated polyester is (5-15):(50-80).

[0010] Optionally, after mixing the acrylic monomer and the initiator to obtain the second mixture, the mass mixing ratio of the acrylic monomer and the initiator in the second mixture is (1-5):(0.01-0.1).

[0011] Optionally, after adding the accelerator and stirring, the total amount of the accelerator, the mass ratio of the acrylic monomer in the second mixture and the acrylic monomer in the first mixture is (0.01-0.05):(1-5):(5-15).

[0012] Optionally, before the waterborne unsaturated polyester and acrylic monomer undergo polymerization, the following procedure is performed:

[0013] In a non-oxidizing atmosphere at 140-160℃, diacids, diols and unsaturated anhydrides are stirred and mixed under the action of polymerization inhibitors and esterification catalysts.

[0014] A water-based unsaturated polyester was obtained by adding a polycondensation catalyst at 190-220℃ for polycondensation and then adjusting the acid value.

[0015] Preferably, the solid content is adjusted after adjusting the acid value to obtain a waterborne unsaturated polyester with a solid content of 75-85%.

[0016] Optionally, during the process of adding the hydrolysis catalyst to the polyester acrylate hybrid solution: the hydrolysis catalyst is at least one of potassium hydroxide solution and sodium hydroxide solution, preferably, the mass concentration of the potassium hydroxide solution and the sodium hydroxide solution is independently 1-10%.

[0017] Optionally, during the process of adding the hydrolysis catalyst to the polyester acrylate hybrid solution, the mass mixing ratio of the hydrolysis catalyst to the polyester acrylate hybrid solution is (8-20):(56-100).

[0018] Optionally, during the process of adding the hydrolysis catalyst to the polyester acrylate hybrid solution: the hydrolysis catalyst is added dropwise to the polyester acrylate hybrid solution in solution form.

[0019] Optionally, after cooling to room temperature, coating additives are added to the polyester acrylate hybrid solution and mixed to obtain a temporary protective water-based coating; wherein the coating additives include wetting agents, thickeners, and plasticizers; wherein: the wetting agent includes at least one of sodium dodecyl sulfate and water-soluble silicone oil; and / or, the thickener includes at least one of polyacrylic acid and sodium carboxymethyl cellulose; and / or, the plasticizer includes at least one of polyethylene glycol and glycerol. Adding a wetting agent improves the overall wettability and stability of the coating, making it easier to handle and apply, thereby improving coating efficiency and coating quality; the addition of a thickener not only controls the viscosity and flowability of the coating but also increases the mechanical stability and abrasion resistance of the coating; the addition of a plasticizer improves the flexibility of the polymer within the coating and enhances its water solubility.

[0020] Secondly, the present invention also provides a temporary protective water-based coating, comprising the following components polymerized to form: water-based unsaturated polyester, acrylic monomer, initiator, accelerator and hydrolysis catalyst; wherein the hydrolysis catalyst is a sodium hydroxide solution or a potassium hydroxide solution with a mass concentration of 1-10%.

[0021] Optionally, the polymer may be formed by polymerization of the following components in parts by mass: 50-80 parts of waterborne unsaturated polyester, 6-20 parts of acrylic monomer, 0.035-0.55 parts of initiator, 0.01-0.05 parts of accelerator and 8-12 parts of hydrolysis catalyst; and the hydrolysis catalyst is a 5% sodium hydroxide solution by mass.

[0022] Thirdly, the present invention also provides a temporary protective water-based coating, which is formed by curing any of the above-mentioned optional water-based coatings.

[0023] Fourthly, the present invention also provides the application of a temporary protective water-based coating on the surface of engineering materials, wherein the engineering materials include metal materials, glass materials and wood materials.

[0024] Optionally, the application includes the following steps: after curing the temporary protective water-based coating onto the surface of the engineering material to be protected, a temporary protective water-based coating is formed; after the temporary protection work is completed, the temporary protective water-based coating on the surface of the engineering material is rinsed with water at a temperature of 20°C. Attached Figure Description

[0025] Figure 1 A flowchart illustrating a method for preparing a temporary protective water-based coating provided by the present invention;

[0026] Figure 2 The particle size distribution diagrams of the coatings provided in Examples 1(a), 2(b), 3(c) and Comparative Example 1(d) of the present invention;

[0027] Figure 3 The water contact angle of the coatings provided in Examples 1(a), 2(b), 3(c) and Comparative Example 1(d) of this invention after curing into a coating. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0029] See Figure 1 This invention provides a method for preparing a temporary protective water-based coating, comprising the following steps:

[0030] S1. Preparation of polyester acrylate hybrid solution: Under a protective atmosphere and with the aid of an initiator and a accelerator, waterborne unsaturated polyester and acrylic monomer undergo free radical graft polymerization to obtain polyester acrylate hybrid solution.

[0031] S2. Preparation of temporary protective water-based coating: Under a stirring environment of 45-55℃, the hydrolysis catalyst is added to the polyester acrylate hybrid solution, and after cooling to room temperature, a temporary protective water-based coating is obtained.

[0032] In fact, the hydrolysis catalyst added in step S2 can hydrolyze the ester groups in the polyester acrylate hybrid to form carboxylic acid groups, thereby improving the overall water solubility of the coating and making it easier to remove water-soluble substances after the coating has cured to form a temporary coating.

[0033] In some embodiments, the hydrolysis catalyst added in step S2 can be added dropwise to the polyester acrylate hybrid solution in the form of a solution, which is beneficial for the hydrolysis catalyst to come into full contact with the polyester acrylate hybrid and to carry out full hydrolysis.

[0034] Specifically, the hydrolysis catalyst can be at least one of potassium hydroxide solution and sodium hydroxide solution. For example, when the hydrolysis catalyst is sodium hydroxide solution, the ester group in the polyester acrylate hybrid can be hydrolyzed into sodium carboxylate group, which has stronger hydrophilicity.

[0035] Specifically, the hydrolysis catalyst can be a potassium hydroxide solution and a sodium hydroxide solution with independent mass concentrations of 1-10%. For example, when the hydrolysis catalyst is a 5% sodium hydroxide solution, the mass mixing ratio of the hydrolysis catalyst to the polyester acrylate hybrid solution is (8-20):(56-100).

[0036] In fact, when the hydrolysis catalyst is a solution of any other concentration, the mass mixing ratio of the hydrolysis catalyst to the polyester acrylate hybrid solution can be adaptively adjusted as follows: "When the hydrolysis catalyst is a 5% sodium hydroxide solution, the mass mixing ratio of the hydrolysis catalyst to the polyester acrylate hybrid solution is (8-20):(56-100)".

[0037] In some embodiments, step S0, which prepares the aqueous unsaturated polyester, is performed before step S1, and includes the following sub-steps:

[0038] S0.1 In a non-oxidizing atmosphere at 140-160℃, under the action of a polymerization inhibitor and an esterification catalyst, a dicarboxylic acid, a diol and an unsaturated anhydride are stirred and mixed.

[0039] S0.2. After polycondensation at 190-220℃, a polycondensation catalyst is added to carry out polycondensation, and the acid value is adjusted to obtain waterborne unsaturated polyester.

[0040] Specifically, the non-oxidizing atmosphere used in step S0.1 can be a nitrogen atmosphere or an inert atmosphere, and the inert atmosphere can be a helium atmosphere or an argon atmosphere.

[0041] Specifically, the polymerization inhibitor used in step S0.1 includes at least one of hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, and 2,5-di-tert-butyl-p-quinone.

[0042] Specifically, the esterification catalyst used in step S0.1 includes at least one of p-toluenesulfonic acid, concentrated sulfuric acid, phosphoric acid, and tin oxide.

[0043] Specifically, the dicarboxylic acid used in step S0.1 includes at least one of isophthalic acid, phthalic acid, terephthalic acid, succinic acid, adipic acid, octanoic acid, sebacic acid, and citric acid. Preferably, the dicarboxylic acid may be citric acid and / or terephthalic acid.

[0044] Specifically, the diol used in step S0.1 includes at least one of propylene glycol, butanediol, hexanediol, neopentyl glycol, and ethylene glycol. Preferably, the diol may be neopentyl glycol.

[0045] Specifically, the unsaturated anhydride used in step S0.1 includes at least one of maleic anhydride, maleic acid, fumaric acid, and itaconic acid. Preferably, the unsaturated anhydride can be maleic anhydride.

[0046] In fact, when performing step S0.1, the diacid, diol and unsaturated anhydride are mixed and dissolved in an organic solvent, which helps to uniformly mix the diacid, diol and unsaturated anhydride, making the polymerization reaction more complete and uniform.

[0047] Specifically, the organic solvent used includes at least one of ethylene glycol butyl ether and propylene glycol butyl ether, and is preferably propylene glycol butyl ether. In some embodiments, the mass mixing ratio of the diacid, diol, unsaturated anhydride and solvent is (23.41-31.53):(35.74-47.52):(1-25.34):(10-40).

[0048] Specifically, the polycondensation catalyst used in step S0.2 includes at least one of dibutyltin dilaurate, antimony glycolate, germanium dioxide, aluminum chloride, and tetrabutyl titanate.

[0049] In some embodiments, the solid content is adjusted after adjusting the acid value in step S0.2 to obtain a waterborne unsaturated polyester with a solid content of 75-85%.

[0050] Specifically, in step S0.2, the following steps are included: maintaining the mixture from S0.1 at 140-160℃ for 0.5-1.5 hours, then raising the temperature to 190-220℃ at a rate of 10-20℃ / hour; stirring the reaction system at 1500-1800 rpm for 4-6 hours; adding the polycondensation catalyst to the reaction system and stirring; maintaining the temperature and measuring the acid value of the reaction system; when the acid value is below 10 mg KOH / g, adjusting the solid content to obtain the waterborne unsaturated polyester. In practice, when adjusting the solid content, the reaction system is cooled to 95-105℃ before adding an organic solvent to adjust the solid content.

[0051] In some embodiments, the protective atmosphere used in step S1 may be one or a mixture of nitrogen atmosphere, inert atmosphere, and specifically, the inert atmosphere may be argon atmosphere or helium atmosphere.

[0052] In some embodiments, the following sub-steps are included in the execution of step S1:

[0053] S1.1. The acrylic monomer and the initiator are mixed to prepare the first mixture and the second mixture;

[0054] S1.2. After adding the first mixture to the aqueous unsaturated polyester and stirring to react, the second mixture is added and mixed to obtain the initial polymerization solution.

[0055] S1.3. After adding the accelerator dropwise to the primary polymerization solution and stirring to mix, the acid value and pH are adjusted to obtain a polyester acrylate hybrid solution.

[0056] In some embodiments, the acrylic monomer used in step S1.1 includes at least one of acrylic acid, methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate, and styrene.

[0057] In some embodiments, the initiator used in step S1.1 includes at least one of cyclohexanone peroxide, methyl ethyl ketone peroxide, and benzoyl peroxide.

[0058] In practice, after performing step S1.1, the mass mixing ratio of acrylic monomer to initiator in the first mixture and the second mixture can be the same or different. Specifically, the mass mixing ratio of acrylic monomer to initiator in the first mixture can be (5-15):(0.025-0.45), and the mass mixing ratio of acrylic monomer to initiator in the second mixture can be (1-5):(0.01-0.1).

[0059] Specifically, in step S1.2, the mass mixing ratio of acrylic monomer to waterborne unsaturated polyester in the first mixture is (5-15):(50-80). In fact, adding the second mixture in step S1.2 further maintains the continuity and efficiency of the polymerization reaction.

[0060] Specifically, after performing step S1.3 of adding the accelerator, the mass ratio of the total amount of accelerator added, the acrylic monomer in the second mixture, and the acrylic monomer in the first mixture is (0.01-0.05):(1-5):(5-15). In fact, adding the accelerator can accelerate the polymerization reaction and optimize the molecular structure of the hybrid.

[0061] Specifically, the accelerator used in step S1.3 includes at least one of dimethylaniline, diethylaniline, and dimethyltoluidine.

[0062] Specifically, in step S1.3, when adjusting the acid value and pH, the reaction system is kept at a constant temperature for 1-3 hours until the acid value is below 10 mg KOH / g, then cooled to 38-62℃ and a pH adjuster is added to adjust the system to neutral. Specifically, the pH adjuster used can be one of ethanolamine, triethylamine, dimethylethanolamine, or ammonia.

[0063] In some embodiments, during step S2, after cooling to room temperature, coating additives are added to the polyester acrylate hybrid solution and mixed to obtain a temporary protective waterborne coating. Specifically, the room temperature is 20-30°C. In practice, the coating additives can be conventional additives permitted in the art for use in coating preparation, to impart other conventional properties to the coating.

[0064] In fact, the coating additives include wetting agents, thickeners, and plasticizers. By adding coating additives, the coating can have a wider range of properties.

[0065] Specifically, the wetting agent includes at least one of sodium dodecyl sulfate and water-soluble silicone oil, and the wetting agent is preferably sodium dodecyl sulfate; specifically, the thickener includes at least one of polyacrylic acid and sodium carboxymethyl cellulose, and the thickener is preferably polyacrylic acid; specifically, the plasticizer includes at least one of polyethylene glycol and glycerol, and the thickener is preferably polyethylene glycol.

[0066] In fact, adding polyacrylic acid as a thickener can not only improve the viscosity of the coating, control its flowability, and increase its mechanical stability and abrasion resistance, but also introduce carboxylic acid groups to further improve the water solubility of the cured coating.

[0067] Meanwhile, based on the above preparation method, the present invention also provides a temporary protective waterborne coating, comprising the following components polymerized to form: waterborne unsaturated polyester, acrylic monomer, initiator, accelerator and hydrolysis catalyst; wherein the hydrolysis catalyst is a sodium hydroxide solution or a potassium hydroxide solution with a mass concentration of 1-10%.

[0068] Specifically, the polymer comprises the following components in parts by mass: 50-80 parts of waterborne unsaturated polyester, 6-20 parts of acrylic monomer, 0.035-0.55 parts of initiator, 0.01-0.05 parts of accelerator and 8-12 parts of hydrolysis catalyst; and the hydrolysis catalyst is a 5% sodium hydroxide solution by mass.

[0069] Based on the aforementioned temporary protective water-based coating, the present invention also provides the application of water-based coatings on the surface of engineering materials, wherein the engineering materials include metal materials, glass materials and wood materials, and in specific applications, the application includes: curing the temporary protective water-based coating on the surface of the engineering material to be protected to form a temporary protective water-based coating; after the temporary protection work is completed, rinsing the temporary protective water-based coating on the surface of the engineering material with water at a temperature of 20°C.

[0070] In fact, when rinsing temporary coatings, the higher the temperature of the rinsing water, the better it is for removing the temporary coating.

[0071] Preparation Example 1

[0072] Example 1 provides a method for preparing an aqueous unsaturated polyester, comprising the following steps:

[0073] S0.1 Add 35.3g neopentyl glycol, 7.5g citric acid, 22.4g terephthalic acid, 16.6g maleic anhydride, 25g propylene glycol butyl ether, 0.009g p-hydroxyanisole, and 0.01g p-toluenesulfonic acid to a 500mL four-necked flask. Install a mechanical stirrer, a nitrogen gas supply, a water separator, and a circulating condenser on the four-necked flask. Under nitrogen protection, heat the four-necked flask to 150℃ and maintain the temperature for 1 hour.

[0074] S0.2. The four-necked flask was heated to 220°C at a rate of 20°C / min, and then stirred at 1500 rpm for 5 hours. 0.01 g of dibutyltin dilaurate was added to the four-necked flask and kept at the temperature with continuous stirring. When the acid value of the reaction system was measured to be lower than 10 mg KOH / g, the four-necked flask was cooled to 100°C and propylene glycol butyl ether was added to adjust the solid content of the system to 80%. The water-based unsaturated polyester was then discharged.

[0075] Example 1

[0076] This Example 1 provides a method for preparing a temporary protective water-based coating based on Preparation Example 1, including the following steps:

[0077] S1.1. Mix 7.0g acrylic acid, 5.5g methyl methacrylate and 0.28g benzoyl peroxide evenly to obtain the first mixture; mix 4.0g acrylic acid and 0.08g benzoyl peroxide evenly to obtain the second mixture.

[0078] S1.2. 65g of waterborne unsaturated polyester is placed into a 500mL four-necked flask, and a mechanical stirrer, a nitrogen protection device, a condenser, and a constant pressure funnel containing the first mixture are installed on the four-necked flask. Under nitrogen protection, the four-necked flask is heated to 100℃, and the first mixture is added dropwise to the waterborne unsaturated polyester while stirring, and the dropping time is controlled to be 3h. After the dropping is completed, the second mixture is added to the four-necked flask and stirred to obtain the initial polymerization solution.

[0079] S1.3 Add 0.03g of dimethylaniline to a four-necked flask, keep warm and stir continuously. After determining that the acid value of the reaction system in the four-necked flask is lower than 10mgKOH / g, cool the four-necked flask to 45℃ and adjust the pH of the system to neutral. Then discharge the material to obtain a polyester acrylate hybrid solution.

[0080] S2. Place 83g of polyester acrylate hybrid solution in a beaker and dilute with deionized water to a solid content of 55%. Heat the beaker to 50°C in a water bath and add 8.5g of 5% sodium hydroxide solution dropwise at a constant speed of 180rpm for 50min. After the addition is complete, cool the beaker to 25°C to obtain a temporary protective water-based coating.

[0081] Example 2

[0082] This embodiment 2 provides a method for preparing a temporary protective water-based coating, which differs from that of embodiment 1 in that: in step S1.1, 7.0g of acrylic acid, 10.5g of butyl acrylate and 0.34g of benzoyl peroxide are uniformly mixed to obtain a first mixture; in step S2, 12.5g of sodium hydroxide solution with a mass concentration of 5% is uniformly added dropwise to a beaker.

[0083] Example 3

[0084] This embodiment 3 provides a method for preparing a temporary protective water-based coating, which differs from that of embodiment 2 in that: in step S2, after cooling the beaker to 25°C, 0.4g of sodium dodecyl sulfate, 3.5g of polyacrylic acid, and 6.5g of polyethylene glycol are added, and the mixture is stirred to obtain a temporary protective water-based coating.

[0085] Comparative Example 1

[0086] Comparative Example 1 provides a method for preparing a temporary protective water-based coating, which differs from Example 1 in that sodium hydroxide solution is not added in step S2.

[0087] Performance testing

[0088] The temporary protective coatings prepared in Examples 1 to 3 and Comparative Example 1 were injected into sponges. A zirconium alloy nuclear fuel rod with a diameter of 10 mm, a wall thickness of 0.5 mm, and a length of 20 cm was wrapped in the sponge to ensure uniform coating. The coatings were then dried and cured in an oven at 45°C to form a film. The curing time of the coatings was calculated and is shown in Table 1 below. The protective coatings formed on the zirconium alloy surface in Examples 1 to 3 and Comparative Example 1 were subjected to the following tests, and the results are shown in Table 1.

[0089] Pencil hardness: The hardness of the coating was measured according to the national standard GB T 6739-1996 "Pencil Test Method for Coating Hardness". The results are shown in Table 1.

[0090] Scratch resistance: A coated zirconium alloy was loaded onto a positioning grid. The positioning grid scratched the coating, leaving scratches. The scratches were observed and the width of the scratches was measured using a metallographic microscope. The test was repeated 3 times and the average value was taken. The results are shown in Table 1.

[0091] Average particle size and aggregation index: The temporary protective coatings prepared in Examples 1 to 3 and Comparative Example 1 were diluted 10 times with deionized water at 25°C and then measured using a dynamic light scattering (DSL) analyzer (ZS Nano S dynamic light scattering particle size analyzer, Malvern, UK). The results are as follows: Figure 2 As shown in Table 1.

[0092] Water contact angle: The temporary protective coatings prepared in Examples 1 to 3 and Comparative Example 1 were applied to a 1cm × 1cm zirconium alloy plate, respectively. After curing into a film, the contact angle at the center of the coating was measured using a 4μL water droplet on a Theta Auto 113 (KSV NIMA). The test results are as follows: Figure 3 As shown in Table 1.

[0093] Water solubility: The coating on the surface of the nuclear fuel rods was rinsed with water at 25°C, and the presence of coating flocculent material in the rinsing water was observed. The results are shown in Table 1.

[0094] Table 1 Performance Testing

[0095]

[0096]

[0097] As can be seen from Table 1, the temporary protective water-based coating provided by the present invention has good protective performance and can protect the surface of engineering materials, such as zirconium alloy fuel rods, thereby avoiding surface scratches during installation or transportation. It also has good water solubility and can be completely washed off with water at 25°C.

[0098] Combining Example 1 and Comparative Example 1, and as can be seen from Table 1, adding a hydrolysis catalyst to the coating can not only significantly improve hydrophilicity and water solubility, but also reduce the emulsion particle size and improve particle size distribution aggregation, thereby improving the scratch resistance of the coating. In the scratch test, the scratch width of Example 1 was reduced by 58%, which shows that the coating prepared in Example 1 can play a better protective role after forming a temporary coating.

[0099] Combining Examples 1 and 2, and as can be seen from Table 1, by adding more ester groups to the coating and adaptively adding more hydrolysis catalyst, the hydrophilicity and water solubility of the resulting coating are improved compared to Example 1.

[0100] Combining Examples 2 and 3, and as can be seen from Table 1, adding sodium dodecyl sulfate, polyacrylic acid, and polyethylene glycol to the coating as coating additives can improve the scratch resistance of the coating and slightly increase its hydrophilicity.

[0101] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for preparing a temporary protective waterborne coating, characterized by, Includes the following steps: In a protective atmosphere, under the action of an initiator and a accelerator, a waterborne unsaturated polyester and an acrylic monomer undergo a polymerization reaction to obtain a polyester acrylate hybrid solution. A hydrolysis catalyst is added to the polyester acrylate hybrid solution under stirring at 45-55°C, and after cooling to room temperature, a temporary protective waterborne coating is obtained. The hydrolysis catalyst is used to hydrolyze ester groups to form carboxylic acid groups, and the hydrolysis catalyst is at least one of potassium hydroxide solution and sodium hydroxide solution. The accelerator includes at least one of dimethylaniline, diethylaniline, and dimethyltoluidine.

2. The production method according to claim 1, characterized by, The process of preparing a polyester acrylate hybrid solution includes: mixing acrylic monomers with an initiator to obtain a first mixture and a second mixture; adding the first mixture to an aqueous unsaturated polyester and stirring to react, then adding the second mixture and mixing, and adding an accelerator dropwise and stirring to mix, adjusting the acid value and pH to obtain the polyester acrylate hybrid solution.

3. The production method according to claim 2, characterized by, After mixing acrylic monomers and initiators to obtain a first mixture, the mass mixing ratio of acrylic monomers to initiators in the first mixture is (5-15):(0.025-0.45); And / or, during the process of adding the first mixture to the waterborne unsaturated polyester and stirring the reaction, the mass mixing ratio of the acrylic monomer in the first mixture to the waterborne unsaturated polyester is (5-15):(50-80); And / or, after mixing acrylic monomers with an initiator to obtain a second mixture, the mass mixing ratio of acrylic monomers to initiators in the second mixture is (1-5):(0.01-0.1); And / or, after adding the accelerator and stirring, the total amount of the accelerator added, the mass ratio of the acrylic monomer in the second mixture and the acrylic monomer in the first mixture is (0.01-0.05):(1-5):(5-15).

4. The production method according to any one of claims 1 to 3, characterized by, Before the polymerization reaction of waterborne unsaturated polyester with acrylic monomers, the following steps should be taken: In a non-oxidizing atmosphere at 140-160℃, diacids, diols and unsaturated anhydrides are stirred and mixed under the action of polymerization inhibitors and esterification catalysts. A water-based unsaturated polyester was obtained by adding a polycondensation catalyst at 190-220℃ for polycondensation and then adjusting the acid value.

5. The preparation method according to claim 4, characterized in that, After adjusting the acid value, the solid content is adjusted to obtain a waterborne unsaturated polyester with a solid content of 75-85%.

6. The method of claim 1, wherein, During the process of adding the hydrolysis catalyst to the polyester acrylate hybrid solution: The mass concentrations of the potassium hydroxide solution and the sodium hydroxide solution are independently 1-10%; And / or, the mass mixing ratio of the hydrolysis catalyst to the polyester acrylate hybrid solution is (8-20):(56-100); And / or, the hydrolysis catalyst is added dropwise to the polyester acrylate hybrid solution in solution form.

7. The preparation method according to claim 1, characterized in that, After cooling to room temperature, coating additives are added to the polyester acrylate hybrid solution and mixed to obtain a temporary protective water-based coating; wherein, the coating additives include wetting agents, thickeners and plasticizers; wherein: the wetting agent includes at least one of sodium dodecyl sulfate and water-soluble silicone oil; and / or, the thickener includes at least one of polyacrylic acid and sodium carboxymethyl cellulose; and / or, the plasticizer includes at least one of polyethylene glycol and glycerol.

8. A temporary protective water-based coating prepared by the preparation method according to any one of claims 1 to 7.

9. A temporary protective water-based coating formed by curing a temporary protective water-based coating prepared by any one of claims 1 to 7.

10. Use of a temporary protective waterborne coating prepared according to the process of any one of claims 1 to 7 on the surface of an engineered material, characterized in that, The engineering materials include metal materials, glass materials, and wood materials.

11. Use according to claim 10, characterized in that, The process includes the following steps: After curing a temporary protective water-based coating onto the surface of the engineering material to be protected, a temporary protective water-based coating is formed; After the temporary protective work is completed, the temporary protective water-based coating on the surface of the engineering material is rinsed with water at a temperature above 20°C.

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