A waterborne interpenetrating polymer network type toughening coating and a preparation method thereof

Abstract

This invention relates to the field of coating technology, specifically to a water-based interpenetrating polymeric network toughening coating and its preparation method. The coating is composed of component A and component B mixed at an epoxy-active hydrogen molar ratio of 1:0.8–1.1. The overall solution of this invention achieves comprehensive optimization in corrosion resistance, weather resistance, toughness, and workability, possessing the application value of a combined topcoat and base coat. Due to the excellent weather resistance provided by the acrylate component in the interpenetrating network, the yellowing and chalking of the epoxy component are inhibited, allowing for long-term outdoor use of the coating. The dense and continuous network structure significantly improves water resistance, acid and alkali resistance, and salt spray resistance, with salt spray protection duration far exceeding that of conventional water-based epoxy coatings. Simultaneously, the coating adhesion is significantly improved, achieving a firm bond on both metal and existing coating surfaces, allowing for single-layer film formation to meet both protective and decorative requirements during application. Due to the synergistic effect of each structural unit and functional component, an environmentally friendly coating with high toughness, high density, strong corrosion resistance, and good weather resistance is ultimately obtained.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a water-based interpenetrating polymeric network toughening coating and its preparation method. Background Technology

[0002] In recent years, environmental protection has become a hot topic in industrial development. While industrial development brings convenience to human life, its impact on nature ultimately affects humanity itself. With the emergence of natural phenomena such as climate change and declining air quality, people are paying increasing attention to environmental protection. In the coatings industry, environmentally friendly coatings are gradually gaining attention. Water-based coatings, as a type of environmentally friendly coating, are also experiencing continuous development.

[0003] Compared to solvent-based coatings, water-based coatings use less solvent and have lower VOC emissions, making them more environmentally friendly and gradually replacing solvent-based coatings. Even under harsh environmental conditions, water-based coatings can provide good corrosion protection for steel. However, the performance of water-based coatings still cannot fully match or surpass that of solvent-based coatings, which limits their development and application.

[0004] Epoxy resins, due to their high content of hydroxyl groups (-OH) and ether bonds (-COC-), exhibit strong adhesion to substrates, especially polar substrates such as metals and concrete. Simultaneously, their high content of hydrocarbon groups (-R) and ether bonds (-COC-) provides excellent chemical resistance. Furthermore, they possess good mechanical and physical properties, such as high hardness, excellent abrasion resistance, scratch resistance, and a high crosslinking density and dense structure, resulting in excellent barrier properties, such as water resistance and corrosion resistance. However, epoxy resins also have inherent disadvantages: ① The flexibility is average, and the resin is too brittle; ② It has poor weather resistance and is prone to yellowing and powdering.

[0005] Therefore, in coating design, epoxy resin coatings are often used as primers, intermediate coats, and topcoats without weather resistance.

[0006] Acrylic resins are widely used in decorative coatings such as topcoats due to their excellent weather resistance and gloss retention.

[0007] Therefore, traditional coating systems require multiple coats of different types of paint to achieve a certain level of protection and decoration. This results in increased construction time and paint consumption, increased environmental waste and pollutants, and ultimately, energy waste.

[0008] To overcome these shortcomings, the market urgently needs a coating that combines protective properties with decorative effects, not only reducing the variety and amount of coatings used and shortening the construction cycle, but also providing the same or better performance as complementary coatings. After a single application, the coating applied to the substrate can be formed into a layer with high adhesion, high density, and a certain degree of weather resistance. To meet the above requirements for coatings, construction, and environmental protection, a special epoxy coating needs to be developed. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and propose a water-based interpenetrating polymeric network toughening coating.

[0010] The specific technical solution is as follows: A water-based interpenetrating polymeric network toughening coating is composed of component A and component B mixed at an epoxy group-active hydrogen molar ratio of 1:0.8-1.1; Component A comprises the following components by mass percentage: 50%–70% interpenetrating polymeric network epoxy emulsion, 0.5%–3% wetting and dispersing agent, 0.01%–0.2% defoamer, 2%–5% functional film-forming aid, 4%–20% pigment, 5%–9% rust-inhibiting pigment, 5%–20% filler, 0.1%–1% wetting and leveling agent, 0.1%–1% rheology modifier, 0.1%–0.5% flash rust inhibitor, and 5%–20% deionized water, with the sum of the mass percentages of each component being 100%. Component B comprises the following components and their mass percentages: 30%–50% water-based modified amine epoxy curing agent and the balance being deionized water.

[0011] As a further technical solution, the interpenetrating polymer network epoxy emulsion is prepared by interpenetrating network polymerization of 30% to 60% aqueous acrylate emulsion and 40% to 70% aqueous epoxy emulsion, and the sum of the mass percentages of the two components is 100%.

[0012] As a further technical solution, the aqueous acrylic emulsion contains the following components by mass percentage: 30%–50% acrylic monomers, 0.03%–1.2% persulfate initiator, 0.2%–1% composite emulsifier, and the balance being deionized water.

[0013] As a further technical solution, the acrylic monomer is selected from at least one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, styrene, sodium styrene sulfonate, and butyl acrylate; the composite emulsifier is an anionic emulsifier and a nonionic emulsifier compounded in a 1:1 mass ratio, and is selected from at least one of BASF Disponil FES32, Solvay Gepal CO430, and Clariant LCN118.

[0014] As a further technical solution, the aqueous epoxy emulsion comprises the following components by mass percentage: 40%–70% liquid bisphenol A type epoxy resin with an epoxy equivalent of 160–200, 4%–10% polyetheramine containing EO segments, and 20%–30% deionized water, prepared by a phase inversion process.

[0015] As a further technical solution, the wetting and dispersing agent is selected from at least one of BYK-190, BYK-191, TEGO715W, TEGO757, and VXW6208 / 60; the defoamer is selected from at least one of BYK-022, BYK-024, BYK-028, TEGO902W, and TEGO901W; and the film-forming aid is selected from at least one of ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, and diethylene glycol butyl ether.

[0016] As a further technical solution, the anti-rust pigment is selected from at least one of ZPA, RZ, ZPO, ZPM, and YR-01; the filler is selected from at least one of precipitated barium sulfate, talc, and calcium sulfate; and the wetting and leveling agent is selected from at least one of BYK-333, BYK-346, BYK-378, TEGO245, and AshlandWET-400.

[0017] As a further technical solution, the rheology modifier is selected from at least one of BYK-425, BYK-428, WT105A, WT113, and WT202; the flash rust inhibitor is selected from at least one of HaloxFlash150, NubiroxFR10, and GF-140.

[0018] As a further technical solution, the B component is composed of: 30%–50% water-based modified amine epoxy curing agent and 50%–70% deionized water; the curing agent is selected from at least one of STW703, KW-8253, H12MDA, EH2162, EH613w, and Aradur38-1.

[0019] A method for preparing a waterborne interpenetrating polymeric network toughening coating includes the following steps: (1) Preparation of waterborne acrylic emulsion: Acrylic monomers, part of the composite emulsifier and deionized water are used to prepare monomer pre-emulsion; the temperature of the remaining emulsifier aqueous solution is raised to 70℃~80℃, and the initiator and monomer pre-emulsion are added dropwise simultaneously. The addition is completed in 4~5h, and the temperature is maintained for 20~30min to obtain waterborne acrylic emulsion. (2) Preparation of waterborne epoxy emulsion: Liquid bisphenol A type epoxy resin is reacted with polyetheramine at 90℃~140℃ for 2~3h to obtain modified epoxy resin, and deionized water is added dropwise to perform phase inversion to obtain waterborne epoxy emulsion. (3) Preparation of interpenetrating polymer network epoxy emulsion: Waterborne acrylate emulsion is added dropwise to waterborne epoxy emulsion at 40℃~70℃, and the addition is completed in 4~6h. The mixture is then kept warm and matured for 1~2h to form a continuous aqueous phase. (4) Preparation of component A: Wetting and dispersing agent and defoamer are added to deionized water and mixed at low speed. Pigment, anti-rust pigment and filler are added in sequence and dispersed at high speed of 800-1200 r / min for 40-60 min. Grind until fineness ≤30 μm. Add interpenetrating polymer network epoxy emulsion, film-forming aid, wetting and leveling agent, rheology modifier and anti-flash rust agent and disperse at 500-800 r / min for 20-60 min. (5) Mix component A and component B in a certain proportion to obtain the toughened coating.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes an interpenetrating polymer network structure design to enable waterborne acrylic emulsions and waterborne epoxy emulsions to interpenetrate and entangle at the nanoscale, thus solving the problem of poor compatibility in traditional blend systems from the perspective of film formation mechanism. Due to the interpenetrating network polymerization process, the acrylic and epoxy molecular chains are not simply physically mixed, but rather form a semi-interpenetrating or interpenetrating continuous phase. This significantly enhances the interfacial bonding force between the two phases and greatly refines the phase region size. This results in a more uniform coating film with fewer defects, fundamentally solving the technical problems of easy phase separation, porous film, and poor media resistance in traditional epoxy-acrylic blend coatings. Simultaneously, the waterborne epoxy emulsion, prepared through polyetheramine modification and phase inversion processes, exhibits higher water dispersion stability and better compatibility with acrylic esters, providing a stable foundation for subsequent network formation.

[0021] The functional components and preparation process of this invention form a synergistic system, resulting in a significant improvement in coating performance. The addition of specific wetting and dispersing agents and defoamers to component A ensures uniform dispersion of pigments and fillers without residual bubbles, achieving stable and compliant fineness after grinding, thus improving the smoothness and density of the paint film. The synergistic effect of anti-rust pigments and anti-flash rust agents inhibits flash rust on the substrate in the early stages of coating curing, and provides long-term protection against water, oxygen, and corrosive ion penetration, enhancing corrosion resistance. Film-forming aids lower the film-forming temperature, ensuring normal film formation at low temperatures, while rheology modifiers adjust the application viscosity, preventing sagging and uneven coating. Because these aids are used in conjunction with the interpenetrating network matrix, the crosslinking density of the cured coating is higher. The flexible segments of acrylate fill the voids in the epoxy network, while the rigid epoxy skeleton provides strength support, resulting in a balance between hardness and toughness, and a simultaneous improvement in impact resistance and crack resistance. This solves the problem of high brittleness and easy cracking in pure epoxy coatings.

[0022] This invention achieves comprehensive optimization in corrosion resistance, weather resistance, toughness, and workability, offering integrated application value for both topcoat and base coat. The acrylate component in the interpenetrating network provides excellent weather resistance, inhibiting yellowing and chalking of the epoxy component, allowing for long-term outdoor use. The dense, continuous network structure significantly improves water resistance, acid and alkali resistance, and salt spray resistance, with salt spray protection duration far exceeding that of conventional water-based epoxy coatings. Simultaneously, coating adhesion is significantly improved, firmly bonding to both metal and existing coating surfaces, allowing for single-layer film formation to meet both protective and decorative requirements. Due to the synergistic effect of each structural unit and functional component, an environmentally friendly coating with high toughness, high density, strong corrosion resistance, and good weather resistance is ultimately obtained, simplifying the construction process, reducing material consumption, and meeting the high-efficiency, environmentally friendly coating needs of engineering machinery and heavy-duty industrial corrosion protection. Attached Figure Description

[0023] Figure 1 This is a flowchart of a method for preparing a water-based interpenetrating polymeric network toughening coating. Detailed Implementation

[0024] 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, and 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.

[0025] This invention provides a water-based interpenetrating polymeric network toughening coating, composed of component A and component B mixed at an epoxy group-active hydrogen molar ratio of 1:0.8-1.1. Component A comprises an interpenetrating polymeric network epoxy emulsion, a wetting and dispersing agent, a defoamer, a functional film-forming aid, pigments, anti-rust pigments, fillers, wetting and leveling agents, rheology modifiers, flash rust inhibitors, and deionized water, with the sum of the mass percentages of all components being 100%. Component B comprises a water-based modified amine epoxy curing agent and deionized water.

[0026] Interpenetrating polymer network epoxy emulsions are prepared by interpenetrating network polymerization of aqueous acrylate emulsions and aqueous epoxy emulsions. The aqueous acrylate emulsions contain acrylic monomers, persulfate initiators, composite emulsifiers, and deionized water. The acrylic monomers are selected from at least one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, styrene, sodium styrene sulfonate, and butyl acrylate. The composite emulsifier is a 1:1 mass ratio of anionic and nonionic emulsifiers, selected from at least one of BASF Disponil FES32, Solvay Gepal CO430, and Clariant LCN118.

[0027] The aqueous epoxy emulsion comprises liquid bisphenol A type epoxy resin with an epoxy equivalent of 160-200, polyetheramine containing EO segments, and deionized water, and is prepared by a phase inversion process.

[0028] The wetting and dispersing agent is selected from at least one of BYK-190, BYK-191, TEGO715W, TEGO757, and VXW6208 / 60. The defoamer is selected from at least one of BYK-022, BYK-024, BYK-028, TEGO902W, and TEGO901W. The film-forming aid is selected from at least one of ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, and diethylene glycol butyl ether.

[0029] The rust-preventive pigment is selected from at least one of ZPA, RZ, ZPO, ZPM, and YR-01. The filler is selected from at least one of precipitated barium sulfate, talc, and calcium sulfate. The wetting and leveling agent is selected from at least one of BYK-333, BYK-346, BYK-378, TEGO245, and AshlandWET-400.

[0030] The rheology modifier is selected from at least one of BYK-425, BYK-428, WT105A, WT113, and WT202. The flash rust inhibitor is selected from at least one of HaloxFlash150, NubiroxFR10, and GF-140.

[0031] Component B contains 30%–50% by mass of water-based modified amine epoxy curing agent, with deionized water as the balance. The curing agent is selected from at least one of STW703, KW-8253, H12MDA, EH2162, EH613w, and Aradur38-1.

[0032] This invention also provides a method for preparing the above-mentioned waterborne interpenetrating polymeric network toughening coating, comprising the following steps: Preparation of waterborne acrylic emulsion: Acrylic monomers, part of the composite emulsifier and deionized water are used to prepare a monomer pre-emulsion; the temperature of the remaining emulsifier aqueous solution is raised to 70℃~80℃, and the initiator and monomer pre-emulsion are added dropwise simultaneously. The addition is completed in 4~5h, and the temperature is maintained for 20~30min to obtain waterborne acrylic emulsion.

[0033] Preparation of waterborne epoxy emulsion: Liquid bisphenol A type epoxy resin is reacted with polyetheramine at 90℃~140℃ for 2~3h to obtain modified epoxy resin. Deionized water is added dropwise to perform phase inversion and obtain waterborne epoxy emulsion.

[0034] Preparation of interpenetrating polymer network epoxy emulsion: Aqueous acrylate emulsion is added dropwise to aqueous epoxy emulsion at 40℃~70℃, and the addition is completed in 4~6h. The mixture is then kept at this temperature for 1~2h to form a continuous aqueous phase.

[0035] Preparation of Component A: Wetting and dispersing agent and defoamer are added to deionized water and mixed at low speed. Pigment, anti-rust pigment and filler are added in sequence and dispersed at high speed of 800-1200 r / min for 40-60 min. Grind until the fineness is ≤30 μm. Add interpenetrating polymeric network epoxy emulsion, film-forming aid, wetting and leveling agent, rheology modifier and anti-flash rust agent and disperse at 500-800 r / min for 20-60 min.

[0036] Component A and component B are mixed in a certain proportion to obtain a toughened coating.

[0037] Example 1: Step 1: Preparation of aqueous acrylic emulsion: 16.3% butyl acrylate, 18.3% methyl methacrylate, 14.0% styrene, and 0.7% sodium styrene sulfonate were weighed as acrylic monomers. 0.34% sodium dodecyl sulfate and 0.17% Solvay Gepal CO430 were weighed as composite emulsifiers. 0.1% potassium persulfate was weighed as an initiator, with deionized water as the remainder. The acrylic monomers, part of the composite emulsifier, and deionized water were mixed and stirred to prepare a monomer pre-emulsion. The remaining emulsifier aqueous solution was heated to 80°C, and the initiator solution and monomer pre-emulsion were added dropwise simultaneously. The addition was completed over 4 hours, and the mixture was kept at this temperature for 30 minutes to obtain an aqueous acrylic emulsion.

[0038] Step 2: Preparation of aqueous epoxy emulsion: Weigh out 66.2% liquid bisphenol A type epoxy resin with an epoxy equivalent of 180, 8.8% polyetheramine containing EO segments, and 25% deionized water. Add the liquid bisphenol A type epoxy resin and polyetheramine to a reactor, heat to 140℃, and react for 3 hours to obtain a modified epoxy resin. Maintain a stirring speed of 500 r / min, and add deionized water dropwise to the modified epoxy resin. The addition is completed in 1.5 hours, and stirring is continued for 1 hour. A waterborne epoxy emulsion is obtained through a phase inversion process.

[0039] Step 3: Preparation of interpenetrating polymeric network epoxy emulsion: Weigh out 48% of waterborne acrylic emulsion and 52% of waterborne epoxy emulsion. Heat the waterborne epoxy emulsion to 50°C, and add the waterborne acrylic emulsion dropwise over 3 hours. Then, keep the mixture at this temperature for 30 minutes to allow it to mature and form a continuous aqueous phase, thus obtaining an interpenetrating polymer network epoxy emulsion.

[0040] Step 4: Prepare component A: Weigh the following components by weight percentage: 58% interpenetrating polymeric network epoxy emulsion, 0.8% VXW6208 / 60 wetting and dispersing agent, 0.2% TEGO902W defoamer, 3% propylene glycol methyl ether film-forming aid, 20% titanium dioxide pigment, 6% ZPA anti-rust pigment, 5% precipitated barium sulfate filler, 0.4% BYK-346 wetting and leveling agent, 0.4% WT105A rheology modifier, 0.2% HaloxFlash150 anti-flash rust agent, and 6% deionized water. Add the deionized water to the paint mixing tank, add the wetting and dispersing agent and defoamer, and stir at low speed until homogeneous. While stirring, add the titanium dioxide, ZPA anti-rust pigment, and precipitated barium sulfate sequentially, disperse at 1000 rpm for 50 minutes, and grind to a fineness of 20 μm using a horizontal sand mill. Interpenetrating polymer network epoxy emulsion, propylene glycol methyl ether, BYK-346, and HaloxFlash150 were added sequentially and dispersed and stirred at 600 r / min for 45 min. Then, WT105A rheology modifier was added and stirred for 60 min to obtain component A.

[0041] Step 5: Obtain the water-based interpenetrating polymeric network toughened coating: Weigh out 45% Aradur 38-1 curing agent and 55% deionized water by mass percentage, and mix them evenly to obtain component B. Mix component A and component B at an epoxy group-active hydrogen molar ratio of 1:0.9 to obtain a water-based interpenetrating polymeric network toughening coating.

[0042] Example 2: Step 1: Preparation of aqueous acrylic emulsion: Weigh out 2% acrylic acid, 15.8% butyl acrylate, 17.8% methyl methacrylate, 13.08% styrene, and 0.64% sodium styrene sulfonate as acrylic monomers; weigh out 0.36% sodium dodecyl sulfate and 0.18% Solvay Gepal CO430 as composite emulsifiers; weigh out 0.12% potassium persulfate as initiator; and deionized water as the remainder. Mix the acrylic monomers, part of the composite emulsifier, and deionized water to prepare a monomer pre-emulsion. Heat the remaining emulsifier aqueous solution to 75°C, and simultaneously add the initiator solution and monomer pre-emulsion dropwise. The addition is completed in 4.5 hours, and the mixture is kept at this temperature for 25 minutes to obtain an aqueous acrylic emulsion.

[0043] Step 2: Preparation of aqueous epoxy emulsion: Weigh out 66.6% of liquid bisphenol A type epoxy resin with an epoxy equivalent of 170, 8.4% of polyetheramine containing EO segments, and 25% deionized water. Add the liquid bisphenol A type epoxy resin and polyetheramine to a reactor, heat to 120℃, and react for 2.5 h to obtain modified epoxy resin. Maintain a stirring speed of 500 r / min, and add deionized water dropwise to the modified epoxy resin. The addition is completed in 1.5 h, and stirring is continued for 1 h. A waterborne epoxy emulsion is obtained through a phase inversion process.

[0044] Step 3: Preparation of interpenetrating polymeric network epoxy emulsion: Weigh out 50% of waterborne acrylic emulsion and 50% of waterborne epoxy emulsion. Heat the waterborne epoxy emulsion to 60°C, and add the waterborne acrylic emulsion dropwise over 4 hours. Then, keep the emulsion at this temperature for 1.5 hours to form a continuous aqueous phase, thus obtaining an interpenetrating polymer network epoxy emulsion.

[0045] Step 4: Prepare component A: Weigh the following components by weight percentage: 62% interpenetrating polymeric network epoxy emulsion, 2.1% BYK-190 wetting and dispersing agent, 0.1% BYK-024 defoamer, 3% diethylene glycol butyl ether film-forming aid, 5% titanium dioxide pigment, 1% phthalocyanine blue pigment, 6% ZPO anti-rust pigment, 6% talc filler, 0.5% TEGO245 wetting and leveling agent, 0.3% WT202 rheology modifier, 0.1% Nubirox FR10 anti-flash rust agent, and 13% deionized water. Add the deionized water to the paint mixing tank, add the wetting and dispersing agent and defoamer, and stir at low speed until homogeneous. While stirring, add the titanium dioxide, phthalocyanine blue, ZPO anti-rust pigment, and talc in sequence, disperse at high speed of 1100 rpm for 45 min, and grind to a fineness of 20 μm using a horizontal sand mill. Interpenetrating polymer network epoxy emulsion, diethylene glycol butyl ether, TEGO245, and Nubirox FR10 were added sequentially and dispersed and stirred at 700 r / min for 50 min. Then, WT202 rheology modifier was added and stirred for 60 min to obtain component A.

[0046] Step 5: Obtain the water-based interpenetrating polymeric network toughened coating: Weigh out 45% STW703 curing agent and 55% deionized water by mass percentage, and mix them evenly to obtain component B. Mix component A and component B at an epoxy group-active hydrogen molar ratio of 1:0.9 to obtain a water-based interpenetrating polymeric network toughening coating.

[0047] Example 3: Step 1: Preparation of aqueous acrylic emulsion: Weigh out 1.1% methacrylic acid, 10.5% ethyl acrylate, 14.7% butyl methacrylate, 10.5% ethyl methacrylate, 10.5% styrene, and 0.8% sodium styrene sulfonate as acrylic monomers; weigh out 0.50% sodium dodecyl sulfate and 0.25% Solvay Gepal CO430 as composite emulsifiers; weigh out 0.15% potassium persulfate as initiator; and deionized water as the remainder. Mix the acrylic monomers, part of the composite emulsifier, and deionized water to prepare a monomer pre-emulsion. Heat the remaining emulsifier aqueous solution to 70°C, and simultaneously add the initiator solution and monomer pre-emulsion dropwise. The addition is completed in 5 hours, and the mixture is kept at this temperature for 20 minutes to obtain an aqueous acrylate emulsion.

[0048] Step 2: Preparation of aqueous epoxy emulsion: Weigh out 68.1% of liquid bisphenol A type epoxy resin with an epoxy equivalent of 160, 6.9% of polyetheramine containing EO segments, and 25% deionized water. Add the liquid bisphenol A type epoxy resin and polyetheramine to a reactor, heat to 90℃, and react for 2 hours to obtain a modified epoxy resin. Maintain a stirring speed of 500 r / min, and add deionized water dropwise to the modified epoxy resin. The addition is completed in 1.5 hours, and stirring is continued for 1 hour. A waterborne epoxy emulsion is obtained through a phase inversion process.

[0049] Step 3: Preparation of interpenetrating polymeric network epoxy emulsion: Weigh out 52% of waterborne acrylic emulsion and 48% of waterborne epoxy emulsion. Heat the waterborne epoxy emulsion to 70°C, and add the waterborne acrylic emulsion dropwise over 5 hours. Then, keep the mixture at this temperature for 2 hours to form a continuous aqueous phase, thus obtaining an interpenetrating polymer network epoxy emulsion.

[0050] Step 4: Prepare component A: Weigh the following components by weight percentage: 65% interpenetrating polymeric network epoxy emulsion, 1.5% TEGO 715W wetting and dispersing agent, 0.1% TEGO 902W defoamer, 4% dipropylene glycol methyl ether film-forming aid, 6% titanium dioxide pigment, 0.4% carbon black pigment, 6% ZPM anti-rust pigment, 10% precipitated barium sulfate filler, 0.5% Ashland WET-400 wetting and leveling agent, 0.4% WT105A rheology modifier, 0.1% Halox Flash 150 anti-flash rust agent, and 6% deionized water. Add the deionized water to the paint mixing tank, add the wetting and dispersing agent and defoamer, and stir at low speed until homogeneous. While stirring, add the titanium dioxide, carbon black, ZPM anti-rust pigment, and precipitated barium sulfate sequentially, disperse at high speed of 1200 rpm for 40 min, and grind to a fineness of 20 μm using a horizontal sand mill. Interpenetrating polymer network epoxy emulsion, dipropylene glycol methyl ether, Ashland WET-400, and Halox Flash 150 were added sequentially and dispersed and stirred at 800 r / min for 60 min. Then, WT105A rheology modifier was added and stirred for 60 min to obtain component A.

[0051] Step 5: Obtain the water-based interpenetrating polymeric network toughened coating: Weigh out 45% EH613w curing agent and 55% deionized water by mass percentage, and mix them evenly to obtain component B. Mix component A and component B at an epoxy group-active hydrogen molar ratio of 1:0.9 to obtain a water-based interpenetrating polymeric network toughening coating.

[0052] Comparative Example 1: The difference from Example 1 is that: instead of using an interpenetrating polymer network epoxy emulsion, only a pure water-based epoxy emulsion was used, while the other components, proportions, and preparation processes were the same.

[0053] Comparative Example 2: The difference from Example 1 is that no water-based acrylic emulsion was added; only water-based epoxy emulsion was used to prepare the base material. The other components, proportions, and preparation processes are the same.

[0054] Comparative Example 3: The difference from Example 1 is that: the interpenetrating network polymerization process was not used, and the waterborne acrylate emulsion and waterborne epoxy emulsion were simply physically blended, while the other components, proportions and preparation processes were the same.

[0055] Comparative Example 4: The difference from Example 1 is that no rust-inhibiting pigments and flash rust inhibitors were added, while the remaining components, proportions, and preparation processes were the same.

[0056] Experimental Section Experiment 1: Testing of Conventional Physical Properties of Coatings Experimental methods The coating was prepared on a standard tinplate sample and cured at room temperature for 7 days. The surface drying time, hard drying time, 60° gloss, pencil hardness, MEK wiping resistance, and pull-off adhesion were tested. Each sample was tested 3 times and the average value was taken.

[0057] Experimental data: Table 1 Examples 1-3 showed significantly better pencil hardness, MEK abrasion resistance, and adhesion than the comparative examples. Comparative Example 1 used a pure water-based epoxy emulsion, resulting in a brittle coating with low crosslinking density, leading to poor hardness and abrasion resistance. Comparative Example 2 lacked an acrylic emulsion, resulting in insufficient coating toughness and decreased abrasion resistance. Comparative Example 3 was only physically blended, resulting in poor compatibility between the two phases, an incomplete network structure, and lower performance than the examples. Comparative Example 4 lacked rust-inhibiting and flash rust-inhibiting components, resulting in a slight decrease in adhesion.

[0058] Experiment 2: Chemical Corrosion Resistance Test of Coating Experimental methods: A coating was prepared on a steel plate and cured at room temperature for 7 days. Then, water resistance, resistance to 5% NaOH, and resistance to 5% H2SO4 were tested. The time when the coating showed no blistering, no peeling, and no rust was recorded.

[0059] Experimental data: Table 2 Examples 1-3 exhibit high coating density and excellent chemical corrosion resistance due to their interpenetrating network structure. Comparative Example 1, with its pure epoxy coating, has numerous pores, allowing for easy media penetration and resulting in extremely poor chemical resistance. Comparative Example 2, lacking acrylate filler, shows decreased alkali and acid resistance. Comparative Example 3 shows physical phase separation, significantly reducing its resistance to media. Comparative Example 4 lacks rust-inhibiting components, making its acid and alkali resistance weaker than the examples.

[0060] Experiment 3: Salt spray and weather resistance test of the coating: Experimental methods: Salt spray resistance test: Tested according to the neutral salt spray standard, and the scratch penetration width was recorded within 1000 hours. Weathering resistance test: Accelerated aging using UVA ultraviolet light was used, and the gloss loss grade, chalking grade, and color difference grade were tested after 800 hours.

[0061] Experimental data: Table 3 Examples 1-3 exhibit excellent salt spray and weather resistance. Comparative Example 1, lacking the acrylate weather-resistant component, failed in salt spray protection. Comparative Example 2, lacking an interpenetrating network, suffered from yellowing and chalking of the epoxy resin, resulting in poor weather resistance. Comparative Example 3 exhibited an unstable phase structure, leading to rapid performance degradation after aging. Comparative Example 4, lacking anti-rust pigments, suffered severe salt spray corrosion.

[0062] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A water-based interpenetrating polymeric network toughening coating, characterized in that, It is composed of component A and component B mixed at a molar ratio of epoxy group to active hydrogen of 1:0.8 to 1.1; Component A comprises the following components by mass percentage: 50%–70% interpenetrating polymeric network epoxy emulsion, 0.5%–3% wetting and dispersing agent, 0.01%–0.2% defoamer, 2%–5% functional film-forming aid, 4%–20% pigment, 5%–9% rust-inhibiting pigment, 5%–20% filler, 0.1%–1% wetting and leveling agent, 0.1%–1% rheology modifier, 0.1%–0.5% flash rust inhibitor, and 5%–20% deionized water, with the sum of the mass percentages of each component being 100%. Component B comprises the following components and their mass percentages: 30%–50% water-based modified amine epoxy curing agent and the balance being deionized water.

2. The coating according to claim 1, characterized in that, The interpenetrating polymer network epoxy emulsion is prepared by interpenetrating network polymerization of 30%–60% aqueous acrylate emulsion and 40%–70% aqueous epoxy emulsion, with the sum of the mass percentages of the two components being 100%.

3. The coating according to claim 2, characterized in that, The aqueous acrylic emulsion comprises the following components by weight percentage: 30%–50% acrylic monomers, 0.03%–1.2% persulfate initiator, 0.2%–1% composite emulsifier, and the balance being deionized water.

4. The coating according to claim 3, characterized in that, The acrylic monomers are selected from at least one or more of acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl acrylate, styrene, sodium styrene sulfonate, and butyl acrylate; the composite emulsifier is an anionic emulsifier and a nonionic emulsifier compounded in a 1:1 mass ratio, and is selected from at least one of BASF Disponil FES32, Solvay Gepal CO430, and Clariant LCN118.

5. The coating according to claim 2, characterized in that, The aqueous epoxy emulsion comprises the following components by mass percentage: 40%–70% liquid bisphenol A type epoxy resin with an epoxy equivalent of 160–200, 4%–10% polyetheramine containing EO segments, and 20%–30% deionized water, prepared by a phase inversion process.

6. The coating according to claim 1, characterized in that, The wetting and dispersing agent is selected from at least one of BYK-190, BYK-191, TEGO715W, TEGO757, and VXW6208 / 60; the defoamer is selected from at least one of BYK-022, BYK-024, BYK-028, TEGO902W, and TEGO901W; and the film-forming aid is selected from at least one of ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, and diethylene glycol butyl ether.

7. The coating according to claim 1, characterized in that, The rust-preventive pigment is selected from at least one of ZPA, RZ, ZPO, ZPM, and YR-01; the filler is selected from at least one of precipitated barium sulfate, talc, and calcium sulfate; and the wetting and leveling agent is selected from at least one of BYK-333, BYK-346, BYK-378, TEGO245, and AshlandWET-400.

8. The coating according to claim 1, characterized in that, The rheology modifier is selected from at least one of BYK-425, BYK-428, WT105A, WT113, and WT202; the flash rust inhibitor is selected from at least one of HaloxFlash150, NubiroxFR10, and GF-140.

9. The coating according to claim 1, characterized in that, The B component is composed of: 30%–50% water-based modified amine epoxy curing agent and 50%–70% deionized water; the curing agent is selected from at least one of STW703, KW-8253, H12MDA, EH2162, EH613w, and Aradur38-1.

10. A method for preparing the waterborne interpenetrating polymeric network toughening coating according to any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Preparation of waterborne acrylic emulsion: Acrylic monomers, part of the composite emulsifier and deionized water are used to prepare monomer pre-emulsion; the temperature of the remaining emulsifier aqueous solution is raised to 70℃~80℃, and the initiator and monomer pre-emulsion are added dropwise simultaneously. The addition is completed in 4~5h, and the temperature is maintained for 20~30min to obtain waterborne acrylic emulsion. (2) Preparation of waterborne epoxy emulsion: Liquid bisphenol A type epoxy resin is reacted with polyetheramine at 90℃~140℃ for 2~3h to obtain modified epoxy resin, and deionized water is added dropwise to perform phase inversion to obtain waterborne epoxy emulsion. (3) Preparation of interpenetrating polymer network epoxy emulsion: Waterborne acrylate emulsion is added dropwise to waterborne epoxy emulsion at 40℃~70℃, and the addition is completed in 4~6h. The mixture is then kept warm and matured for 1~2h to form a continuous aqueous phase. (4) Preparation of component A: Wetting and dispersing agent and defoamer are added to deionized water and mixed at low speed. Pigment, anti-rust pigment and filler are added in sequence and dispersed at high speed of 800-1200 r / min for 40-60 min. Grind until fineness ≤30 μm. Add interpenetrating polymer network epoxy emulsion, film-forming aid, wetting and leveling agent, rheology modifier and anti-flash rust agent and disperse at 500-800 r / min for 20-60 min. (5) Mix component A and component B in a certain proportion to obtain the toughened coating.

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