Epoxy ester modified waterborne alkyd resin composition and its preparation method

Abstract

This invention provides an epoxy ester-modified waterborne alkyd resin composition and its preparation method. First, an epoxy ester intermediate A containing conjugated double bonds and an alkyd resin intermediate B containing non-conjugated double bonds are prepared. The mixture of these two intermediates is then chain-extended using polyisocyanate C. Next, hydrophilic monomer components, hydrophobic monomer components, and a mixture component are added dropwise to graft-modify the chain-extended epoxy ester intermediate A and alkyd resin intermediate B. Taking advantage of the fact that the conjugated double bonds of epoxy ester intermediate A readily copolymerize with vinyl monomers, the grafting rate of the hydrophilic vinyl monomer E onto epoxy ester intermediate A is increased. Furthermore, by introducing a functional repair monomer G, the ungrafted vinyl polymer segments in the epoxy ester-modified waterborne alkyd resin composition are ensured to participate in the crosslinking reaction during film formation, reducing the adverse effects of ungrafted components on coating performance and thus significantly improving the initial water resistance and corrosion resistance of the coating.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, and in particular, relates to an epoxy ester modified waterborne alkyd resin composition and its preparation method. Background Technology

[0002] Alkyd resins possess excellent comprehensive properties. Their raw materials are widely available, not entirely dependent on petrochemical products, and their production costs are relatively less affected by oil prices, making them widely used in industrial protection. However, waterborne alkyd resin coatings themselves have many performance defects, such as slow film drying, low hardness, poor corrosion resistance and outdoor weather resistance, and poor hydrolysis resistance due to the large number of ester bonds. To address these performance defects, chemical modification of waterborne alkyd resins is usually required. Currently, the most commonly used modification methods include two types: (1) vinyl monomer modification of waterborne alkyd resins; and (2) epoxy resin modification of waterborne alkyd resins. The process route for vinyl monomer modification of alkyd resins typically begins with esterification to prepare alkyd resin intermediates. Based on this, graft copolymerization is performed on the alkyd resin intermediates using hydrophilic vinyl monomers (such as acrylic acid) to obtain water-dispersible vinyl-modified waterborne alkyd resins. In the graft modification of epoxy esters using vinyl monomers, a portion of the vinyl monomers grafts onto the oleic acid segments of the alkyd resin, forming a vinyl polymer-alkyd resin copolymer; another significant portion of the vinyl monomers undergoes self-polymerization, forming vinyl monomer self-polymers. Therefore, the waterborne alkyd resin prepared by existing techniques is actually a mixture, primarily consisting of the vinyl polymer-alkyd resin copolymer, ungrafted alkyd resin polymer, and vinyl monomer self-polymers. Due to the low molecular weight of the vinyl monomer self-polymers and their presence of hydrophilic vinyl monomer polymer segments, they represent a weak point in the performance of the waterborne alkyd resin composition. The relative content of this component in the mixture significantly affects the water resistance and corrosion resistance of the waterborne alkyd resin. Furthermore, during the modification of waterborne alkyd resins with vinyl monomers, the copolymerization reaction leads to a loss of unsaturated alkyd resin, reducing oxygen crosslinking active sites and resulting in a low crosslinking density in the early stages of film formation in the waterborne alkyd coating, thus affecting initial water resistance. On the other hand, when using epoxy resin to modify waterborne alkyd resin, the epoxy resin is generally added to the esterification process of the alkyd resin. Since the epoxy resin contains a lot of secondary hydroxyl groups, the viscosity is difficult to control during the esterification process, and it is easy to gel, which leads to problems in product quality control. Summary of the Invention

[0003] The purpose of this invention is to provide an epoxy ester modified waterborne alkyd resin composition to solve the technical problem that the existing vinyl monomer modified waterborne alkyd resin has a high content of vinyl monomer self-polymers, and the loss of unsaturation of alkyd resin causes a reduction in oxidative crosslinking active sites, resulting in a low crosslinking density in the early stage of film formation of waterborne alkyd resin coatings, which affects the initial water resistance and anti-corrosion performance of waterborne alkyd resin coatings.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An epoxy ester modified waterborne alkyd resin composition is provided, wherein the raw material composition of the epoxy ester modified waterborne alkyd resin composition, based on a 100% percentage of the total mass of the raw materials, comprises 20.26–64.38% of a mixed monomer component, 6–22% of epoxy ester intermediate A, 31–60% of alkyd resin intermediate B, 0.8–2% of polyisocyanate C, and 2.4–4.8% of neutralizing agent D. The mixed monomer component includes a hydrophilic monomer component, a hydrophobic monomer component, and a mixture component. The hydrophilic monomer component comprises the following components in the following percentages:

[0005] Hydrophilic vinyl monomer E 2.5–4%;

[0006] Initiator F 0.01–0.08%;

[0007] The hydrophobic monomer component comprises the following components in the following percentages:

[0008] Functional repair monomer G 2.5–8.4%;

[0009] Non-hydrophilic vinyl monomer H 13-40%;

[0010] Initiator I: 0.18–1.5%;

[0011] The mixture comprises the following components in the following percentages:

[0012] Initiator J: 0.07–0.4%;

[0013] Solvent K 2-10%.

[0014] Optionally, based on a percentage of 100% of the total mass of the raw materials constituting the epoxy ester intermediate A, the epoxy ester intermediate A comprises the following components in the following percentages:

[0015]

[0016] Optionally, the molar ratio of the fatty acid M to the epoxy resin L is (1.95 to 2.05):1.

[0017] Optionally, the fatty acid M is at least one of tung oil acid and dehydrated ricinoleic acid, and the epoxy resin L is a bisphenol A type epoxy resin with an epoxy value of 0.09 to 0.14 mol / 100g.

[0018] Optionally, based on a percentage of 100% of the total mass of the raw materials constituting the alkyd resin intermediate B, the raw material composition of the alkyd resin intermediate B includes 15-22% fatty acid Q, 1.7-3.6% benzoic acid, 18-25% diacid, 5-11% diol, 12-18% polyol, 0.05-0.25% catalyst R, 3.0-8.5% dehydrating solvent S, and 25-35% diluent T.

[0019] Optionally, the functional repair monomer G is prepared by glycidyl methacrylate and linolenic acid via a ring-opening esterification reaction.

[0020] Optionally, the initiator F and / or the initiator I are at least one of tert-amyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide acetate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxidecyclohexane, 2,2-di(tert-butylperoxide)butane, and tert-butyl peroxide, and the initiator J is at least one of di-tert-butyl peroxide and di-tert-amyl peroxide.

[0021] Optionally, the hydrophilic vinyl monomer E is at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer H is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene.

[0022] Another objective of this invention is to provide a method for preparing the above-mentioned epoxy ester modified waterborne alkyd resin composition.

[0023] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for preparing an epoxy ester-modified waterborne alkyd resin composition capable of preparing any of the epoxy ester-modified waterborne alkyd resin compositions provided by the above solutions, wherein the method for preparing the epoxy ester-modified waterborne alkyd resin composition includes the following steps:

[0024] Step S01: Weigh each raw material according to the components contained in the epoxy ester modified waterborne alkyd resin composition according to any one of claims 1 to 8;

[0025] Step S02: Mix epoxy ester intermediate A and alkyd resin intermediate B, and stir evenly to obtain the first epoxy ester modified alkyd resin intermediate mixture.

[0026] Step S03: Heat the first epoxy ester modified alkyd resin intermediate mixture to 70-80°C, and add polyisocyanate C dropwise over 1-2 hours to obtain the second epoxy ester modified alkyd resin intermediate mixture.

[0027] Step S04: Heat the second epoxy ester modified alkyd resin intermediate mixture to 110-140°C, and add the mixed monomer component dropwise to the second epoxy ester modified alkyd resin intermediate mixture.

[0028] Step S05: The second epoxy ester modified alkyd resin intermediate mixture containing the mixed monomer components is kept at 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D is added to prepare the epoxy ester modified waterborne alkyd resin composition.

[0029] Optionally, in step S04, the mixed monomer component includes a hydrophilic monomer component, a hydrophobic monomer component, and a mixing agent component. During the process of adding the mixed monomer component to the second epoxy ester modified alkyd resin intermediate mixed component, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours, followed by the hydrophobic monomer component over 3 to 4 hours. Then, the temperature of the second epoxy ester modified alkyd resin intermediate mixed component is adjusted to 130 to 150°C, and the mixing agent component is added dropwise over 1 to 2 hours.

[0030] Compared with the prior art, one or more technical solutions in the embodiments of the present invention have at least one of the following beneficial effects:

[0031] The epoxy ester-modified waterborne alkyd resin composition in the embodiments of the present invention, or the epoxy ester-modified waterborne alkyd resin composition prepared by the preparation method in the embodiments of the present invention, involves chain extension of epoxy ester intermediate A and alkyd resin intermediate B via diisocyanate. This chain extension process includes three different types of reactions: between the alkyd resin intermediate and the epoxy ester intermediate, between alkyd resin intermediates themselves, and between epoxy ester intermediates. Through the above chain extension treatment of epoxy ester intermediate A and alkyd resin intermediate B, epoxy ester segments can be introduced into the alkyd resin. Simultaneously, through the polyaddition reaction of diisocyanate with hydroxyl groups, some alkyd resin intermediate B and epoxy ester intermediate A are linked together by chemical bonds, significantly improving the hardness and initial water resistance of the waterborne alkyd resin.

[0032] The preparation method of the epoxy ester modified waterborne alkyd resin composition in this invention embodiment, on the one hand, extends the alkyd resin component by diisocyanate, increasing the probability of hydrophilic groups in a single polymer chain and further ensuring the storage stability of the non-uniformly distributed waterborne polymer. On the other hand, in the stage of grafting and modifying epoxy ester intermediate A and alkyd resin intermediate B with vinyl monomers, a segmented dropwise addition method is used to add the hydrophilic monomer component and the hydrophobic monomer component separately: First, when there are many grafting sites in the epoxy ester intermediate and the alkyd resin intermediate, the hydrophilic monomer component containing the hydrophilic vinyl monomer E is added dropwise to increase the grafting rate of the hydrophilic vinyl monomer E and reduce the adverse effects of the hydrophilic chain segment on the water resistance and corrosion resistance of the coating; Second, the second step involves adding the hydrophobic monomer component containing the functional repair monomer G and the hydrophilic vinyl monomer E. By designing and introducing the functional repair monomer G to copolymerize with other vinyl monomers, the hydrophobic monomer component is added dropwise in the waterborne alkyd resin intermediate. During the film-forming process of the acid composition, the polymer that did not participate in the graft copolymerization of the epoxy ester intermediate contains linolenic acid segments. These segments can undergo oxidative crosslinking with fatty acid segments in the waterborne alkyd resin during film formation, reducing the adverse effects of the ungrafted components on the performance of the waterborne alkyd resin, thereby further improving the resin's water resistance and corrosion resistance. Furthermore, since the double bond of epoxy ester intermediate A is a conjugated fatty acid, the conjugated double bond has higher copolymerization activity with vinyl monomers. Vinyl monomers (especially the hydrophilic vinyl monomer E added in the first step) preferentially graft copolymerize with epoxy ester intermediate A, resulting in a relatively lower hydrophilic content in the waterborne alkyd resin intermediate. During the water dispersion process, the alkyd resin polymer segments with poor hydrolysis resistance coil inside the micelles. Since the water resistance, hydrolysis resistance, and corrosion resistance of the alkyd resin segments are worse than those of the epoxy ester segments, the lower hydrophilicity of these segments is beneficial to improving the water resistance, hydrolysis resistance, and corrosion resistance of the final product. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0034] This invention provides an epoxy ester-modified waterborne alkyd resin composition. The raw material composition of this epoxy ester-modified waterborne alkyd resin composition, based on 100% of the total raw material mass, includes 20.26–64.38% of a mixed monomer component, 6–22% of epoxy ester intermediate A, 31–60% of alkyd resin intermediate B, 0.8–2% of polyisocyanate C, and 2.4–4.8% of neutralizing agent D. The mixed monomer component includes hydrophilic monomer components, hydrophobic monomer components, and a mixture component. The hydrophilic monomer component includes the following components in the following percentages:

[0035] Hydrophilic vinyl monomer E 2.5–4%;

[0036] Initiator F 0.01–0.08%;

[0037] The hydrophobic monomer component comprises the following components in the following percentages:

[0038] Functional repair monomer G 2.5–8.4%;

[0039] Non-hydrophilic vinyl monomer H 13-40%;

[0040] Initiator I: 0.18–1.5%;

[0041] The mixture comprises the following components in the following percentages:

[0042] Initiator J: 0.07–0.4%;

[0043] Solvent K 2-10%.

[0044] In some embodiments, epoxy ester intermediate A comprises the following components in percentages based on 100% of the total mass of the raw materials constituting epoxy ester intermediate A:

[0045]

[0046]

[0047] The epoxy ester-modified waterborne alkyd resin composition prepared by the method provided in this invention, compared with the prior art, involves chain extension of epoxy ester intermediate A and alkyd resin intermediate B via diisocyanate. This chain extension process includes three different types of reactions: between the alkyd resin intermediate and the epoxy ester intermediate, between alkyd resin intermediates themselves, and between epoxy ester intermediates. Through the above chain extension treatment of epoxy ester intermediate A and alkyd resin intermediate B, epoxy ester segments can be introduced into the alkyd resin. Simultaneously, through the polyaddition reaction of diisocyanate with hydroxyl groups, some alkyd resin intermediate B and epoxy ester intermediate A are linked together by chemical bonds, significantly improving the hardness and initial water resistance of the waterborne alkyd resin.

[0048] It should be noted that, in some embodiments, the raw material composition of epoxy ester intermediate A includes fatty acid M, epoxy resin L, polymerization inhibitor N, catalyst O, and solvent P. The molar ratio of fatty acid M to epoxy resin L is (1.95–2.05):1, the total mass of fatty acid M and epoxy resin L accounts for 67–73% of the total mass of epoxy ester intermediate A, solvent P accounts for 28.0–32.0% of the total mass of epoxy ester intermediate A, polymerization inhibitor N accounts for 0.05–0.5% of the total mass of epoxy ester intermediate A, and catalyst O accounts for 0.2–2.0% of the total mass of epoxy ester intermediate A. Under nitrogen protection, the mixture is stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature is lowered to 90℃, and solvent P is added to obtain epoxy ester intermediate A.

[0049] It should be noted that in some embodiments, fatty acid M is at least one of tung oil acid and dehydrated ricinoleic acid, epoxy resin L is bisphenol A type epoxy resin with an epoxy value of 0.09-0.14 mol / 100g, polymerization inhibitor N is at least one of 2,6-di-tert-butyl-p-cresol and hydroquinone, catalyst O is at least one of triphenylphosphine and tetrabutylammonium bromide, and solvent P is at least one of propylene glycol methyl ether acetate, ethylene glycol butyl ether acetate, and methyl isobutyl ketone.

[0050] It should be noted that, in some embodiments, the raw material composition of alkyd resin intermediate B includes fatty acid Q, benzoic acid, diacid, diol, polyol, catalyst R, dehydrating solvent S, and diluent T. Alkyd resin intermediate B is prepared by esterification reaction of fatty acid Q, benzoic acid, diacid, diol, polyol, catalyst R, and dehydrating solvent S. Specifically, the preparation method of alkyd resin intermediate B includes the following steps: fatty acid Q, benzoic acid, diacid, diol, polyol, catalyst R, and dehydrating solvent S are added to a reaction vessel equipped with a water separator. The temperature is slowly raised to 100-130°C, and the molten powder is kept at this temperature for 1 hour. Stirring is started, and the temperature is gradually raised to 200-230°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature is lowered to 160-180°C. The dehydrating solvent S is removed by vacuuming, and the temperature is lowered to 90-100°C. Diluent T is added while stirring to obtain alkyd resin intermediate B.

[0051] It should be noted that, in some embodiments, fatty acid Q is at least one of oleic acid, linoleic acid, linolenic acid, and soybean oil; catalyst R is at least one of triphenylphosphine, dibutyltin dilaurate, and monobutyltin oxide; dehydrating solvent S is at least one of pseudotrimethylbenzene, mesitylene, C9 aromatics, methyl isobutyl ketone, and solvent oil D40; diluent T is at least one of propylene glycol methyl ether acetate, ethylene glycol butyl ether acetate, methyl isobutyl ketone, and butanone; diacid is at least one of phthalic anhydride, isophthalic acid, adipic acid, and sebacic acid; diol is at least one of neopentyl glycol, hexanediol, butanediol, and diethylene glycol; and polyol is at least one of trimethylolpropane and glycerol.

[0052] It should be noted that, in some embodiments, the specific preparation steps of alkyd resin intermediate B are as follows: fatty acid P, epoxy resin Q, catalyst R, and dehydrating solvent S are added to a reaction vessel equipped with a water separator, the temperature is slowly raised to 100-130°C, and the epoxy resin is melted by holding at this temperature for 1 hour. Stirring is started, and the temperature is raised to 200-230°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature is lowered to 160-180°C, the dehydrating solvent S is removed by vacuuming, and the temperature is lowered to 90-100°C. While stirring, diluent T is added to obtain alkyd resin intermediate B.

[0053] It should be noted that, in some embodiments, the hydrophilic vinyl monomer E is at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer H is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene.

[0054] It should be noted that, in some embodiments, the initiator F is at least one of tert-amyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide acetate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxidecyclohexane, 2,2-di(tert-butylperoxide)butane, and tert-butyl peroxide.

[0055] It should be noted that, in some embodiments, initiator I is at least one of tert-amyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide acetate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxidecyclohexane, 2,2-di(tert-butylperoxide)butane, and tert-butyl peroxide.

[0056] It should be noted that, in some embodiments, the initiator J is at least one of di-tert-butyl peroxide and di-tert-pentyl peroxide.

[0057] It should be noted that, in some embodiments, the functional repair monomer G is prepared by a ring-opening esterification reaction of glycidyl methacrylate and linolenic acid. The specific preparation steps of the functional repair monomer G include: adding 556.0 g of linolenic acid, 142.0 g of glycidyl methacrylate, 0.7 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 7.0 g of catalyst triphenylphosphine to a reactor equipped with a stirrer and thermometer. Under nitrogen protection, the mixture is stirred and heated to 140±5℃ for a ring-opening esterification reaction. After maintaining this temperature for 5 hours, the reaction temperature is lowered to 90-95℃ to prepare the functional repair monomer G.

[0058] The present invention also provides a method for preparing the epoxy ester modified waterborne alkyd resin composition of any of the above embodiments.

[0059] In some embodiments, the preparation method of the epoxy ester modified waterborne alkyd resin composition provided by the present invention includes the following steps:

[0060] Step S01: Weigh each raw material according to the components contained in the epoxy ester modified waterborne alkyd resin composition in any of the above embodiments.

[0061] Step S02: Mix epoxy ester intermediate A and alkyd resin intermediate B, and stir evenly to obtain the first epoxy ester modified alkyd resin intermediate mixture.

[0062] Step S03: Heat the first epoxy ester modified alkyd resin intermediate mixture to 70-80°C, and add polyisocyanate C dropwise over 1-2 hours to obtain the second epoxy ester modified alkyd resin intermediate mixture.

[0063] Step S04: Heat the second epoxy ester modified alkyd resin intermediate mixture to 110–140°C, and add the mixed monomer components dropwise to the second epoxy ester modified alkyd resin intermediate mixture. The mixed monomer components include hydrophilic monomer components, hydrophobic monomer components, and a mixing agent component. During the dropwise addition of the mixed monomer components to the second epoxy ester modified alkyd resin intermediate mixture, the hydrophilic monomer components are added first over 0.5–1.5 hours, followed by the hydrophobic monomer components over 3–4 hours. Then, the temperature of the second epoxy ester modified alkyd resin intermediate mixture is adjusted to 130–150°C, and the mixing agent component is added dropwise over 1–2 hours.

[0064] Step S05: The second epoxy ester modified alkyd resin intermediate mixed component containing the mixed monomer components is kept at a temperature of 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D is added to prepare the epoxy ester modified waterborne alkyd resin composition.

[0065] The preparation method of the epoxy ester modified waterborne alkyd resin composition in this invention embodiment, compared with the prior art, on the one hand, increases the probability of hydrophilic groups in a single polymer chain by extending the alkyd resin component through diisocyanate, further ensuring the storage stability of the non-uniformly distributed waterborne polymer. On the other hand, in the stage of grafting and modifying epoxy ester intermediate A and alkyd resin intermediate B with vinyl monomers, a segmented dropwise addition method is used to add the hydrophilic monomer component and the hydrophobic monomer component separately: First, when there are many grafting sites in the epoxy ester intermediate and the alkyd resin intermediate, the hydrophilic monomer component containing the hydrophilic vinyl monomer E is added dropwise to increase the grafting rate of the hydrophilic vinyl monomer E and reduce the adverse effects of the hydrophilic chain segment on the water resistance and corrosion resistance of the coating; Second, the second step involves adding the hydrophobic monomer component containing the functional repair monomer G and the hydrophilic vinyl monomer E, by designing and introducing the functional repair monomer G to copolymerize with other vinyl monomers. During the film-forming process of the waterborne alkyd composition, the polymer that did not participate in the graft copolymerization of the epoxy ester intermediate contains linoleic acid segments. These segments can undergo oxidative crosslinking with the fatty acid segments in the waterborne alkyd resin during film formation, reducing the adverse effects of the ungrafted components on the performance of the waterborne alkyd resin, thereby further improving the resin's water resistance and corrosion resistance. Furthermore, since the double bond of epoxy ester intermediate A is a conjugated fatty acid, the conjugated double bond has higher copolymerization activity with vinyl monomers. Vinyl monomers (especially the hydrophilic vinyl monomer E added in the first step) preferentially graft copolymerize with epoxy ester intermediate A, resulting in a relatively lower hydrophilic content in the waterborne alkyd resin intermediate. During the resin dispersion process, the alkyd resin polymer segments with poor hydrolysis resistance coil inside the micelles. Since the water resistance, hydrolysis resistance, and corrosion resistance of the alkyd resin segments are worse than those of the epoxy ester segments, the lower hydrophilicity of these segments is beneficial to improving the water resistance, hydrolysis resistance, and corrosion resistance of the final product.

[0066] To enable those skilled in the art to clearly understand the above-described implementation details and operations of the present invention, and to demonstrate the significant improvement in performance of the epoxy ester modified waterborne alkyd resin composition and its preparation method, the following examples illustrate the implementation of the present invention.

[0067] The raw materials involved in the following examples and comparative examples include:

[0068] NPES-904 epoxy resin, industrial grade, Nan Ya Electronic Materials (Kunshan) Co., Ltd.; Ethylene glycol butyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, industrial grade, Nanjing Gutian Chemical Co., Ltd.; Ethylene glycol tert-butyl ether, industrial grade, Maruzen, Japan; Pseudotrimethylbenzene, chemically pure, Shanghai Aladdin Biochemical Technology Co., Ltd.; Methyl isobutyl ketone, industrial grade, Shandong Baien; Monobutyltin oxide, industrial grade, Shanghai Titan Technology Co., Ltd.; 2,6-Di-tert-butyl-p-cresol, ultrapure grade, Shanghai Aladdin Biochemical Technology Co., Ltd.; Triphenylphosphine, industrial grade, Anhui Jinshan Chemical Technology Co., Ltd.; Benzoic acid, phthalic anhydride, isophthalic acid, neopentyl glycol, 1,6-hexanediol, trimethylolpropane, glycerol, soybean oil acid, oleic acid, linoleic acid, linolenic acid, acrylic acid, methacrylic acid, styrene, butyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl acrylate, industrial grade, CNOOC Changzhou Environmental Protection Coatings Co., Ltd. tert-butyl peroxide (TBPB), di-tert-amyl peroxide (DTAP), di-tert-butyl peroxide (DTBP), industrial grade, AkzoNobel; tert-amyl peroxide-2-ethylhexanoate (TAPO), industrial grade, Shandong Haijing New Material Co., Ltd.; 2,2-di(tert-butylperoxide)butane, industrial grade, Nantong Runfeng Petrochemical Co., Ltd.; N,N-dimethylethanolamine (DMEA), industrial grade, Eastman Chemical Co., Ltd.; AMP-95 Industrial grade, Dow Chemical (USA); High-efficiency composite drying agent TY-CQ-4210WD, industrial grade, Shanghai Taoyuan Cobalt Co., Ltd.; BYK-022, BYK-190, BYK-346, industrial grade, BYK Corporation; Carbon black, industrial grade, Degussa; Titanium dioxide R-902+, industrial grade, Chemours (USA); Precipitated barium sulfate, industrial grade, Nanfeng Group; Zinc phosphate, industrial grade, Guangxi Xinjing Technology Co., Ltd.; Strontium chrome yellow, industrial grade, Changzhou Deshuo Chemical; TEGO Airex 901W, industrial grade, DIGIC. 299, Industrial grade, Hemings; Unless otherwise stated, all raw materials used in the examples and comparative examples are commercially available products that can be purchased through commercial channels.

[0069] Example 1

[0070] Preparation of epoxy ester intermediate A1: In a reactor equipped with a stirrer and thermometer, 25.99 g of tung oil acid, 77.87 g of NPES-904 epoxy resin, 0.10 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 1.04 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90℃, and 45.00 g of propylene glycol methyl ether acetate was added to obtain epoxy ester intermediate A1.

[0071] Example 2

[0072] Preparation of epoxy ester intermediate A2: In a reactor equipped with a stirrer and thermometer, 25.99 g of dehydrated ricinoleic acid, 77.87 g of NPES-904 epoxy resin, 0.25 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 1.55 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90℃, and 45.00 g of methyl isobutyl ketone was added to obtain epoxy ester intermediate A2.

[0073] Example 3

[0074] Preparation of epoxy ester intermediate A3: In a reactor equipped with a stirrer and thermometer, 25.99 g of dehydrated castor oil acid, 77.87 g of NPES-904 epoxy resin, 0.28 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 1.64 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90℃, and 25.00 g of propylene glycol methyl ether acetate and 20.00 g of methyl isobutyl ketone were added to obtain epoxy ester intermediate A3.

[0075] Example 4

[0076] Preparation of alkyd resin intermediate B1: 57.57 g soybean oil acid, 38.01 g linolenic acid, 11.52 g benzoic acid, 51.81 g phthalic anhydride, 62.19 g isophthalic acid, 28.80 g neopentyl glycol, 11.52 g 1,6-hexanediol, 69.09 g trimethylolpropane, 0.48 g triphenylphosphine, and 17.28 g pseudotrimethylbenzene were added to a reaction vessel equipped with a water separator. The temperature was slowly raised to 120°C and kept at this temperature for 1 hour to melt the powder. Stirring was started, and the temperature was gradually increased to 220°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature was lowered to 180°C, and pseudotrimethylbenzene was removed by vacuum. The temperature was then lowered to 90-100°C, and 146.70 g methyl isobutyl ketone was added while stirring to obtain alkyd resin intermediate B1.

[0077] Example 5

[0078] Preparation of alkyd resin intermediate B2: 180.00 g of linoleic acid, 30.00 g of benzoic acid, 62.00 g of phthalic anhydride, 122.00 g of isophthalic acid, 45.00 g of neopentyl glycol, 135.00 g of trimethylolpropane, 2.02 g of monobutyltin oxide, and 47.00 g of pseudotrimethylolpropane were added to a reaction vessel equipped with a water separator. The temperature was slowly raised to 130°C and kept at this temperature for 1 hour to melt the powder. Stirring was started, and the temperature was gradually increased to 215°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature was lowered to 170°C, and pseudotrimethylolpropane was removed by vacuum. The temperature was then lowered to 90-100°C, and 220.00 g of propylene glycol methyl ether acetate was added while stirring to obtain alkyd resin intermediate B2.

[0079] Example 6

[0080] Preparation of alkyd resin intermediate B3: 93.00 g soybean oil acid, 87.00 g oleic acid, 20.00 g benzoic acid, 120.00 g phthalic anhydride, 95.00 g isophthalic acid, 50.00 g neopentyl glycol, 110.00 g glycerol, 0.80 g monobutyltin oxide, and 50.00 g methyl isobutyl ketone were added to a reaction vessel equipped with a water separator. The temperature was slowly raised to 120°C and kept at this temperature for 1 hour to melt the powder. Stirring was started, and the temperature was gradually increased to 230°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature was lowered to 180°C, and methyl isobutyl ketone was removed by vacuum. The temperature was then lowered to 90-100°C, and 260.00 g propylene glycol methyl ether acetate was added while stirring to obtain alkyd resin intermediate B3.

[0081] Example 7

[0082] Preparation of functional repair monomer G: In a reactor equipped with a stirrer and a thermometer, 556 g of linolenic acid, 142 g of glycidyl methacrylate, 0.7 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 7 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90-95℃ and the mixture was discharged to obtain functional repair monomer G.

[0083] Examples 8-12 and Comparative Examples 1-6 below describe the preparation of epoxy ester-modified waterborne alkyd resin compositions based on the synthesis in Examples 1-7. It should be noted that before synthesizing the epoxy ester-modified waterborne alkyd resin compositions, a mixed monomer component was prepared according to the formulation in any of the above examples. The mixed monomer component included a hydrophilic monomer component, a hydrophobic monomer component, and a mixture component. Specifically, the hydrophilic monomer component included a hydrophilic vinyl monomer E and an initiator F; the hydrophobic monomer component included a functional repair monomer G, a non-hydrophilic vinyl monomer H, and an initiator I; and the mixture component included an initiator J and a solvent K.

[0084] Example 8

[0085] The preparation method of epoxy ester modified waterborne alkyd resin composition a includes the following steps: According to the formulation in Table 1, 150 g of epoxy ester intermediate A1 and 450 g of alkyd resin intermediate B1 are mixed and stirred evenly. The mixture is then heated to 70-75°C, and polyisocyanate C is added dropwise. The addition is completed within 2 hours at 70-75°C. After the addition is completed, the temperature is raised to 115-125°C, and vinyl monomer mixed components are added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 115–125°C. After the hydrophilic monomer component is added, the hydrophobic monomer component is added dropwise over 3 to 4 hours at 115–125°C. Then, the temperature is adjusted to 130–140°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 130–140°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition a.

[0086] Example 9

[0087] The preparation method of epoxy ester modified waterborne alkyd resin composition b includes the following steps: According to the formulation in Table 1, 220 g of epoxy ester intermediate A2 and 310 g of alkyd resin intermediate B2 are mixed and stirred evenly. The mixture is then heated to 75-80°C, and polyisocyanate C is added dropwise. The addition is completed within 2 hours at 75-80°C. After the addition is completed, the temperature is raised to 110-120°C, and the vinyl monomer mixture is added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 110–120°C. After the hydrophilic monomer component is added, the hydrophobic monomer component is added dropwise over 3 to 4 hours at 110–120°C. Then, the temperature is adjusted to 145–150°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 145–150°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition b.

[0088] Example 10

[0089] The preparation method of epoxy ester modified waterborne alkyd resin composition C includes the following steps: According to the formulation in Table 1, 60 grams of epoxy ester intermediate A1 and 360 grams of alkyd resin intermediate B3 are mixed and stirred evenly. The mixture is then heated to 75-80°C, and polyisocyanate C is added dropwise. The addition is completed within 1.5 hours at 75-80°C. After the addition is completed, the temperature is raised to 125-135°C, and the vinyl monomer mixture is added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 125–135°C. After the hydrophilic monomer component is added, the hydrophobic monomer component is added dropwise over 3 to 4 hours at 125–135°C. Then, the temperature is adjusted to 140–145°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 140–145°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition c.

[0090] Example 11

[0091] The preparation method of epoxy ester modified waterborne alkyd resin composition d includes the following steps: According to the formulation in Table 1, 80 g of epoxy ester intermediate A2 and 600 g of alkyd resin intermediate B3 are mixed and stirred evenly. The mixture is then heated to 73-76°C, and polyisocyanate C is added dropwise. The addition is completed within 2 hours at 73-76°C. After the addition is completed, the temperature is raised to 125-135°C, and vinyl monomer mixed components are added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 125–135°C. After the hydrophilic monomer component is added, the hydrophobic monomer component is added dropwise over 3 to 4 hours at 125–135°C. Then, the temperature is adjusted to 130–140°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 130–140°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition d.

[0092] Example 12

[0093] The preparation method of epoxy ester modified waterborne alkyd resin composition e includes the following steps: According to the formulation in Table 1, 180 g of epoxy ester intermediate A3 and 500 g of alkyd resin intermediate B2 are mixed and stirred evenly. The mixture is then heated to 78-80°C, and polyisocyanate C is added dropwise. The addition is completed within 2 hours at 78-80°C. After the addition is completed, the temperature is raised to 130-140°C, and the vinyl monomer mixture is added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 130–140°C. After the hydrophilic monomer component is added, the hydrophobic monomer component is added dropwise over 3 to 4 hours at 130–140°C. Then, the temperature is adjusted to 140–150°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 140–150°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition e.

[0094] Comparative Example 1

[0095] Preparation of waterborne epoxy ester resin composition f: According to the formulation in Table 2, 600g of epoxy ester intermediate A1 was stirred evenly, and the temperature was raised to 70-75℃. Polyisocyanate C was then added dropwise over 2 hours at 70-75℃. After the addition was complete, the temperature was raised to 115-125℃, and the vinyl monomer mixture was added dropwise. First, the hydrophilic monomer component was added dropwise over 0.5-1.5 hours at 115-125℃. After the hydrophilic monomer component addition was complete, the hydrophobic monomer component was added dropwise over 3-4 hours at 115-125℃. Then, the temperature was adjusted to 130-140℃, and the mixture was added dropwise over 1-2 hours. During the addition of the mixed monomer components, the resin viscosity became too high, causing gelation, and the reaction was stopped, failing to prepare waterborne epoxy ester resin composition f.

[0096] Table 1. Raw material composition and formulation of the epoxy ester modified waterborne alkyd resin compositions in Examples 8 to 12

[0097]

[0098] Comparative Example 2

[0099] Preparation of waterborne alkyd resin composition h: According to the formulation in Table 2, 600 g of alkyd resin intermediate B1 was mixed and stirred evenly. The temperature was raised to 70-75°C, and polyisocyanate C was added dropwise over 2 hours at 70-75°C. After the addition was completed, the temperature was raised to 115-125°C, and the vinyl monomer mixture was added dropwise. First, the hydrophilic monomer component was added dropwise over 0.5-1.5 hours at 115-125°C. After the hydrophilic monomer component was added, the hydrophobic monomer component was added dropwise over 3-4 hours at 115-125°C. Then, the temperature was adjusted to 130-140°C, and the mixture was added dropwise over 1-2 hours. After the addition was completed, the temperature was maintained at 130-140°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D was added to prepare the waterborne alkyd resin composition h.

[0100] Comparative Example 3

[0101] Preparation of waterborne alkyd resin composition i: According to the formulation in Table 2, 600 g of alkyd resin intermediate X was stirred evenly, and the temperature was raised to 70-75°C. Polyisocyanate C was then added dropwise over 2 hours at 70-75°C. After the addition was completed, the temperature was raised to 115-125°C, and the vinyl monomer mixture was added dropwise. First, the hydrophilic monomer component was added dropwise over 0.5-1.5 hours at 115-125°C. After the hydrophilic monomer component was added, the hydrophobic monomer component was added dropwise over 3-4 hours at 115-125°C. Then, the temperature was adjusted to 130-140°C, and the mixture was added dropwise over 1-2 hours. After the addition was completed, the temperature was maintained at 130-140°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D was added to prepare epoxy ester modified waterborne alkyd resin composition i.

[0102] The preparation process of alkyd resin intermediate X is as follows: 25.99 g of tung oil acid, 57.57 g of soybean oil acid, 38.01 g of linolenic acid, 11.52 g of benzoic acid, 51.81 g of phthalic anhydride, 62.19 g of isophthalic acid, 28.80 g of neopentyl glycol, 11.52 g of 1,6-hexanediol, 69.09 g of trimethylolpropane, 77.87 g of NPES-904 epoxy resin, 1.52 g of triphenylphosphine, and 0.10 g of polymerization inhibitor 2,6-diphenylphosphine were prepared. 17.28 g of tert-butyl-p-cresol and pseudotrimethylbenzene were added to a reaction vessel equipped with a water separator. The temperature was slowly raised to 120°C and kept at this temperature for 1 hour to melt the powder. Stirring was started, and the temperature was gradually increased to 220°C at a rate of 20°C / hour. After holding at this temperature for 5 hours, the temperature was lowered to 180°C, and pseudotrimethylbenzene was removed by vacuuming. The temperature was then lowered to 90-100°C, and 45.00 g of propylene glycol methyl ether acetate and 146.70 g of methyl isobutyl ketone were added while stirring to prepare alkyd resin intermediate X.

[0103] During the preparation of alkyd resin intermediate X, the resin viscosity became too high and gelled when the temperature was gradually increased to 220°C, causing the reaction to stop and alkyd resin intermediate X to fail to be prepared. Consequently, epoxy ester modified waterborne alkyd resin composition i could not be prepared.

[0104] Comparative Example 4

[0105] Preparation of epoxy ester modified waterborne alkyd resin composition j: According to the formulation in Table 1, 150 g of epoxy ester intermediate A1 and 450 g of alkyd resin intermediate B1 were mixed and stirred evenly. The mixture was then heated to 115–125 °C, and the vinyl monomer mixture was added dropwise. First, the hydrophilic monomer component was added dropwise, and the addition was completed within 0.5–1.5 hours at 115–125 °C. After the hydrophilic monomer component was added, the hydrophobic monomer component was added dropwise at 115–125 °C, and the addition was completed within 3–4 hours. Then, the temperature was adjusted to 130–140 °C, and the mixture component was added dropwise, and the addition was completed within 1–2 hours. After the addition was completed, the temperature was maintained at 130–140 °C for 1–2 hours, and then the temperature was lowered to 90–100 °C. Neutralizing agent D was added to prepare epoxy ester modified waterborne alkyd resin composition j.

[0106] Comparative Example 5

[0107] Preparation of epoxy ester modified waterborne alkyd resin composition k: According to the formulation in Table 2, epoxy ester intermediate A1 and alkyd intermediate B1 were mixed in the specified proportions and stirred evenly. The mixture was then heated to 70-75°C, and polyisocyanate C was added dropwise over 2 hours at 70-75°C. After the addition was completed, the temperature was raised to 115-125°C, and the hydrophilic and hydrophobic monomer components were mixed and added dropwise simultaneously over 4-5 hours. Then, the temperature was adjusted to 130-140°C, and the mixed component was added dropwise over 1-2 hours. After the addition was completed, the mixture was kept at 130-140°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D was added to prepare epoxy ester modified waterborne alkyd resin composition k.

[0108] Comparative Example 6

[0109] The preparation method of epoxy ester modified waterborne alkyd resin composition 1 includes the following steps: according to the formulation in Table 2, epoxy ester intermediate A1 and alkyd intermediate B1 are mixed in a stoichiometric ratio, stirred evenly, and then heated to 70-75°C. Polyisocyanate C is then added dropwise and the addition is completed within 2 hours at 70-75°C. After the addition is completed, the temperature is raised to 115-125°C, and the vinyl monomer mixture is added dropwise. First, the hydrophilic monomer component is added dropwise over 0.5 to 1.5 hours at 115–125°C. After the hydrophilic monomer component is added, the hydrophobic monomer component without the functional repair monomer G is added dropwise over 3 to 4 hours at 115–125°C. Then, the temperature is adjusted to 130–140°C and the mixture component is added dropwise over 1 to 2 hours. After the addition is completed, the temperature is maintained at 130–140°C for 1 to 2 hours, then cooled to 90–100°C, and neutralizing agent D is added to prepare epoxy ester modified waterborne alkyd resin composition 1.

[0110] Table 2. Raw material composition and formulation of resin compositions in Comparative Examples 1 to 6

[0111]

[0112] Preparation of waterborne alkyd resin coatings and performance testing of waterborne alkyd resin coatings:

[0113] The aqueous alkyd resin compositions prepared in Examples 8-11 and Comparative Examples 2-6 above were used as film-forming resins to prepare aqueous alkyd resin coatings. The formulations of the aqueous alkyd resin coatings are shown in Table 3, and the preparation process of the aqueous alkyd resin coatings is as follows:

[0114] (1) According to the formulation in Table 3, the film-forming resin (a, b, c, d, e in the examples and h, j, k, l in the comparative examples), the drying agent (TY-CQ4210 WD), and the pH adjuster (N,N-dimethylethanolamine) are first stirred and mixed evenly at a stirring speed of 1000 rpm. Deionized water is added while stirring, and after stirring for 30 min, an aqueous resin dispersion is obtained.

[0115] (2) Add materials 5 to 12 of Table 3 to the reaction vessel in sequence, then add them to the stirring tank, mix and stir for 40 to 60 minutes, then start grinding until the fineness is <30μm;

[0116] (3) While stirring, add material 13 to adjust the viscosity, filter and discharge to obtain water-based alkyd resin coating. Filter, discharge and package. According to the different film-forming resins used, the prepared coatings are successively named Ca, Cb, Cc, Cd, Ce, and the comparative coatings Ch, Cj, Ck, Cl, Cm.

[0117] Table 3 Formulations of Waterborne Alkyd Resin Coatings

[0118]

[0119] The prepared water-based alkyd resin coating was diluted with water to adjust to an appropriate viscosity. The coating was then sprayed onto a polished cold-rolled steel plate with a film thickness of 50–60 μm. After surface drying at room temperature, the sample was placed in an oven at 80±2℃ for 30 minutes and left at room temperature for 7 days. The coating properties were then tested according to the national standard test method for coatings.

[0120] In addition, the resins prepared in the above examples and comparative examples were characterized by testing the rotational viscosity, gel content, and monomer conversion rate of the resin compositions. For waterborne alkyd resin coatings, the main tests included coating appearance, surface drying time, adhesion, water resistance, initial water resistance, and resistance to neutral salt spray.

[0121] Rotational viscosity: The rotational viscosity of the epoxy ester modified waterborne alkyd resin composition was tested using an NDJ-8S rotational viscometer.

[0122] Thermal storage stability of dispersions: abbreviated as thermal storage of dispersions. To test the storage stability of epoxy ester modified waterborne alkyd resins, a measured proportion of the waterborne resin composition was weighed, and deionized water was added while stirring to prepare an waterborne resin dispersion with a solid content of 42.5%. The dispersion was placed in a constant temperature drying oven at 50±2℃, and observed every day for phenomena such as stratification, settling, coagulation, precipitation, and agglomeration. If any of the above phenomena occurred, the storage stability was deemed poor, and the observation was continued for more than 14 days.

[0123] Gel content: The resin grafting rate is characterized by gel content. The specific test method is as follows: Weigh the aqueous resin composition, add 5 wt% of TY-CQ4210 WD drying agent to the total resin mass, stir evenly, form a film on a tetrafluoroethylene plate, bake at 80℃ for 2 hours after surface drying, and place at 25±2℃ for 7 days. Collect the solid resin and weigh it, recording the mass as M0 grams. Perform Soxhlet extraction, dry the extracted sample and weigh it, recording the weight as M1. Gel content = (M0-M1) / M0×100%.

[0124] Residual monomer content: The residual monomer content was determined using an Agilent 8890 gas chromatograph.

[0125] Initial water resistance: After spraying the sample, dry it in a standard constant temperature and humidity room at 25±2℃ for 24 hours. After edge sealing, place the sample in deionized water in a constant temperature room at 25±2℃, with about 2 / 3 of the sample immersed in water. Observe the coating condition every 2 hours within 24 hours, and observe it every 12 hours after 24 hours, until the coating blister, wrinkle or the substrate rusts. The initial water resistance is judged by the time it takes for the coating to be damaged.

[0126] Neutral salt spray resistance test: The corrosion resistance performance of the coating is determined by the neutral salt spray resistance test, in accordance with GB / T1771-2007. The test is conducted every 24 hours until the coating blisteres, rusts or peels off.

[0127] Other properties of the coating were tested in accordance with the relevant national standards, and the relevant test results are listed in Tables 4 and 5.

[0128] Table 4 shows the test results of the aqueous alkyd resin compositions in Examples 8 to 12 and Comparative Examples 1 to 6.

[0129] Test Project Rotational viscosity (mPa·s) Gel content (%) Residual monomer content (%) Dispersion-based thermal storage (days) Example 8 30550 71.05 0.62 ≥14 Example 9 39760 62.51 0.49 ≥14 Example 10 38710 59.80 0.81 ≥14 Example 11 35940 67.49 0.46 ≥14 Example 12 29680 69.10 0.52 ≥14 Comparative Example 1 gel / / / Comparative Example 2 23360 57.65 1.38 ≥14 Comparative Example 3 gel / / / Comparative Example 4 22460 64.79 0.58 Soft bottom after 7 days Comparative Example 5 28830 69.24 0.86 ≥14 Comparative Example 6 26110 62.31 0.79 ≥14

[0130] Table 5 shows the test results of the performance of the waterborne alkyd resin coatings in Examples 7 to 11 and Comparative Examples 2 to 6.

[0131]

[0132] As can be seen from the data in Table 4, the rotational viscosity of the epoxy ester modified waterborne alkyd resin compositions prepared using the embodiments of the present invention is all below 40000 mPa·s, the gel content is all above 59%, and the residual monomer content is all below 0.9%.

[0133] As shown in Table 5, the epoxy ester-modified waterborne alkyd resin composition of the present invention, used as the film-forming agent, produces waterborne alkyd resin coatings with excellent performance. The waterborne alkyd resin coatings have a smooth and even appearance, and the pencil hardness of the coatings all exceed B, meeting the requirements for industrial coating primers. It is particularly noteworthy that, through polymer segment molecular design and process innovation, the coatings prepared using the preparation method provided in the present invention achieve a neutral salt spray resistance time of 300 hours, exhibiting excellent corrosion resistance, and initial water resistance reaches 120 hours, meeting the latest requirements for initial water resistance and corrosion resistance in the automotive parts industry.

[0134] Comparing Example 8 with Comparative Example 1, since Comparative Example 1 used only epoxy ester intermediate A1 containing conjugated double bonds to prepare waterborne resin, and because the conjugated double bonds have high activity, the waterborne epoxy ester resin in Comparative Example 1 was unable to be prepared because the viscosity was too high and it gelled.

[0135] Comparing Example 8 with Comparative Example 2, where only alkyd resin intermediate B1 was used, the gel content decreased from 71.05% in Example 8 to 57.65% in Comparative Example 2. Furthermore, the initial water resistance of the coating of the epoxy ester modified waterborne alkyd resin composition h in Comparative Example 2 was reduced to 72 hours, and the neutral salt spray resistance time was reduced to 240 hours.

[0136] Comparing Example 8 with Comparative Example 3, the rotational viscosity of the epoxy ester modified waterborne alkyd resin composition a prepared in Example 8 using a mixture of epoxy ester intermediate A1 and alkyd resin intermediate B1 was 30550 mPa·s. In contrast, Comparative Example 3 used a one-step esterification method to prepare alkyd resin intermediate X to synthesize epoxy ester modified waterborne alkyd resin composition i. During the preparation of alkyd resin intermediate X, the resin viscosity was high during the high-temperature esterification stage, resulting in gelation and failure to successfully synthesize epoxy ester modified waterborne alkyd resin composition i.

[0137] Example 8 was compared with Comparative Example 4. Comparative Example 4 had a similar formulation and process to Example 8, the only difference being that polyisocyanate C was not used for chain extension in Comparative Example 4. The rotational viscosity of the epoxy ester-modified waterborne alkyd resin composition prepared in Comparative Example 4 decreased from 30550 mPa·s in Example 8 to 22460 mPa·s. However, it is noteworthy that the thermal storage stability of the epoxy ester-modified waterborne alkyd resin dispersion prepared from the synthetic resin in Comparative Example 4 decreased from more than 14 days to 7 days, corresponding to a decrease in the initial water resistance of the coating from 120 h to 72 h, and a decrease in the neutral salt spray resistance time from 300 h to 240 h.

[0138] Example 8 was compared with Comparative Example 5. Comparative Example 5 had a similar formulation and process to Example 8, the only difference being the change in the dropwise addition process. Instead of the segmented dropwise addition of the hydrophilic and hydrophobic monomer components in Example 8, the process in Comparative Example 5 involved simultaneous dropwise addition. All other process conditions were identical to Example 8. The epoxy ester-modified waterborne alkyd resin compositions prepared in Example 8 and Comparative Example 5 had similar rotational viscosity, gel content, and residual monomer content. However, it is noteworthy that the initial water resistance of the coating corresponding to Comparative Example 5 decreased from 120 h to 48 h, and the neutral salt spray resistance time decreased from 360 h to 240 h.

[0139] Example 8 was compared with Comparative Example 6. Comparative Example 6 had a similar formulation and process to Example 8, the only difference being that "functional repair monomer G" was not used in Comparative Example 6. The viscosity of the epoxy ester modified waterborne alkyd resin prepared in Comparative Example 5 was reduced to 26110 mPa·s, while the gel content was reduced to 62.31%. Correspondingly, the initial water resistance of the corresponding epoxy ester modified waterborne alkyd resin coating in Comparative Example 2 was reduced to 72 h, and the neutral salt spray resistance time was reduced to 240 h.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy ester modified waterborne alkyd resin composition, characterized in that, The raw material composition of the epoxy ester modified waterborne alkyd resin composition, based on 100% of the total raw material mass, includes 20.26–64.38% of a mixed monomer component, 6–22% of epoxy ester intermediate A, 31–60% of alkyd resin intermediate B, 0.8–2% of polyisocyanate C, and 2.4–4.8% of neutralizing agent D. The mixed monomer component includes hydrophilic monomer components, hydrophobic monomer components, and a mixture component. The hydrophilic monomer component comprises the following components in the following percentages: Hydrophilic vinyl monomer E 2.5-4%; Initiator F 0.01–0.08%; The hydrophobic monomer component comprises the following components in the following percentages: Functional repair monomers G2.5–8.4%; Non-hydrophilic vinyl monomers H13-40%; Initiator I: 0.18–1.5%; The mixture comprises the following components in the following percentages: Initiator J: 0.07–0.4%; Solvent K2~10%, The functional repair monomer G is prepared by glycidyl methacrylate and linolenic acid through a ring-opening esterification reaction. The hydrophilic vinyl monomer E is at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer H is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene. The preparation method of the epoxy ester modified waterborne alkyd resin composition includes the following steps: Step S01: Weigh each raw material according to the components contained in the epoxy ester modified waterborne alkyd resin composition; Step S02: Mix epoxy ester intermediate A and alkyd resin intermediate B, and stir evenly to obtain the first epoxy ester modified alkyd resin intermediate mixture. Step S03: Heat the first epoxy ester modified alkyd resin intermediate mixture to 70-80°C, and add polyisocyanate C dropwise over 1-2 hours to obtain the second epoxy ester modified alkyd resin intermediate mixture. Step S04: Heat the second epoxy ester modified alkyd resin intermediate mixture to 110-140°C, and add mixed monomer components dropwise to the second epoxy ester modified alkyd resin intermediate mixture. The mixed monomer components include hydrophilic monomer components, hydrophobic monomer components, and a mixture component. During the dropwise addition of the mixed monomer components to the second epoxy ester modified alkyd resin intermediate mixture, the hydrophilic monomer components are added dropwise over 0.5-1.5 hours, followed by the hydrophobic monomer components over 3-4 hours. Then, the temperature of the second epoxy ester modified alkyd resin intermediate mixture is adjusted to 130-150°C, and the mixture component is added dropwise over 1-2 hours. Step S05: The second epoxy ester modified alkyd resin intermediate mixed component containing the mixed monomer components is kept at a temperature of 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent D is added to prepare the epoxy ester modified waterborne alkyd resin composition.

2. The epoxy ester modified waterborne alkyd resin composition according to claim 1, characterized in that, Based on a percentage of 100% of the total mass of the raw materials constituting the epoxy ester intermediate A, the epoxy ester intermediate A comprises the following components in the following percentages: A mixture of fatty acid M and epoxy resin L, comprising 67-73%; Polymerization inhibitor N: 0.05%–0.5%; Catalyst O 0.2-2%; Solvent P28~32%.

3. The epoxy ester modified waterborne alkyd resin composition according to claim 2, characterized in that, The molar ratio of the fatty acid M to the epoxy resin L is (1.95~2.05):

1.

4. The epoxy ester modified waterborne alkyd resin composition according to claim 2 or 3, characterized in that, The fatty acid M is at least one of tung oil acid and dehydrated ricinoleic acid, and the epoxy resin L is a bisphenol A type epoxy resin with an epoxy value of 0.09 to 0.14 mol / 100g.

5. The epoxy ester modified waterborne alkyd resin composition according to claim 1, characterized in that, Based on a percentage of 100% of the total mass of the raw materials constituting the alkyd resin intermediate B, the raw material composition of the alkyd resin intermediate B includes 15-22% fatty acid Q, 1.7-3.6% benzoic acid, 18-25% diacid, 5-11% diol, 12-18% polyol, 0.05-0.25% catalyst R, 3.0-8.5% dehydrating solvent S, and 25-35% diluent T.

6. The epoxy ester modified waterborne alkyd resin composition according to claim 1, characterized in that, The initiator F and / or the initiator I are at least one of tert-amyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide acetate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxidecyclohexane, 2,2-di(tert-butylperoxide)butane, and tert-butyl peroxide, and the initiator J is at least one of di-tert-butyl peroxide and di-tert-amyl peroxide.

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