Two-component coating composition, process for preparing the two-component coating composition, and coated article.

Description

34 Two-component coating composition, process for preparing the two-component coating composition, and coated article. Cross-reference to related filing applications.

[001] This application is an international patent application claiming priority to Chinese Patent Application No. 202310334627. X, filed March 30, 2023, which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[002] The application relates to the technical field of anti-corrosion of metallic surfaces or substrates. In particular, the present application relates to a two-component coating composition, a process for preparing the same and a coated article. BACKGROUND

[003] With the rapid development of the economy, coatings on metallic surfaces or substrates are facing more and more problems, and performance requirements are becoming more stringent and demanding.

[004] For example, in most existing anti-corrosion coating systems, a primer, an intermediate paint, a topcoat, or a composite anti-corrosion coating system of primer and topcoat is adopted. Due to the complex application processes, such systems have several disadvantages, including long construction periods and high cost.

[005] In addition, a large amount of organic solvents is used in most traditional anti-corrosion coating systems. As environmental issues attract increasing attention, laws and regulations for environmental protection in various countries and regions are being enacted. Petition 870250088113, dated 09 / 29 / 2025, page 12 / 50 / 34, making them more stringent, therefore it is increasingly important to reduce the amount of organic solvents in coating systems. Water-based anticorrosive systems proposed by some researchers involve a modified hydrophilic curing agent. However, this modified hydrophilic curing agent usually involves complex synthesis processes and raw materials, which greatly increases the cost of coatings and affects the popularization and application of water-based coatings. Furthermore, the coating layers formed from existing water-based anticorrosive coatings generally show relatively unsatisfactory coating performance properties, such as reduced gloss, insufficient resistance to salt spray, etc. SUMMARY

[006] In view of this, there is a need for an anti-corrosion coating system that not only has good workability and satisfactory environmental protection performance, but can also provide excellent coating performance. More specifically, there is a need for a coating system that is simple to apply, sustainable and environmentally friendly, and capable of providing an anti-corrosion coating with excellent salt spray resistance, weather resistance, mechanical properties, adhesion and chemical resistance.

[007] The above objective can be achieved using the two-component coating composition described herein.

[008] A first aspect of the present application provides a two-component coating composition comprising: a component A comprising at least one hydroxy-functional polyurethane dispersion and an anti-rust pigment, and a component B comprising a non-hydrophilic isocyanate curing agent, and component A has a rate of change in grinding fineness after 14 days at 40 °C of 10% or less relative to the initial fineness of component A, and the Petition 870250088113, dated 09 / 29 / 2025, page 13 / 50 / 34 fineness is measured with a fineness plate according to standard GB / T 17242019.

[009] A second aspect of the present application provides a process for preparing a two-component coating composition comprising mixing a component A and a component B, characterized in that component A comprises at least a hydroxy-functional polyurethane dispersion and an anti-rust pigment, component B comprises a non-hydrophilic isocyanate curing agent and component A has a rate of change in grinding fineness after 14 days at 40 °C of 10% or less relative to an initial fineness of component A and the fineness is measured with a fineness plate in accordance with GB / T 1724-2019.

[0010] A third aspect of the present application provides a coated article, characterized in that the coated article comprises: a metallic substrate having at least one principal surface; and the two-component coating composition as described herein or a cured coating formed therefrom, applied to at least one principal surface of the metallic substrate.

[0011] The inventors have surprisingly discovered that the two-component coating composition described in the present application has the following advantages, including simple construction, sustainable and environmental protection, and the ability to provide an anti-corrosion coating with excellent performance (such as salt spray resistance, weather resistance, mechanical properties, adhesion, and chemical resistance). In particular, the coating or cured coating film of the present application has one or more of the following properties: absence of bubble formation at 35 °C for at least 1000 hours in the neutral salt spray test on aluminum plate, phosphate plate, or both; absence of bubble formation at 20 °C for at least 120 hours in sulfuric acid solution. Petition 870250088113, dated 09 / 29 / 2025, page 14 / 50 / 34 5%, absence of bubble formation at 20 °C for at least 120 hours in a 5% sodium hydroxide solution, Δε of 1.0 or lower, and light retention at 60 °C greater than 80% after exposure to a xenon lamp for 1000 hours.

[0012] Furthermore, the two-component coating and coating composition of the present application have advantages including low VOC (the amount of organic solvent being 15% or less in relation to the total weight of the composition, or even no solvent) and low cost, therefore they are healthy and environmentally friendly products and are easier to be accepted and popularized by consumers.

[0013] The summary above of this application is not intended to describe every embodiment disclosed or every implementation in this application. Illustrative embodiments are exemplified in more detail in the detailed description that follows. DETAILED DESCRIPTION Selected definitions

[0014] As used herein, the terms a, an, such, at least one, and one or more may be employed interchangeably unless otherwise indicated. Thus, for example, a coating composition comprising an additive may be interpreted as indicating that the coating composition comprises one or more additives. Unless otherwise indicated herein, the use of singular forms herein is intended to include plural forms.

[0015] Unless expressly stated otherwise, the use of the terms comprising, including, containing and having, and variations thereof, should generally be interpreted as open-ended and not limiting. For example, when a composition is described as comprising, including, containing or having certain components, it is intended that the composition may include other optional components besides those listed above. Petition 870250088113, dated 09 / 29 / 2025, page 15 / 50 / 34 specific components expressly listed and that the composition may consist of or be composed of the specific components; when a method is described as comprising, including, containing or having certain steps, it is intended that the method may include other optional steps in addition to the specific steps expressly shown and that the method may consist of or be composed of the specific steps.

[0016] For the sake of brevity, only a few numerical ranges are explicitly revealed here. However, any lower limit can be combined with any upper limit to form a range that is not explicitly described; and any lower limit can be combined with another lower limit to form an unspecified range; and any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, although not explicitly specified, each unique point or value between the endpoints of a range is included in the range. Thus, each unique point or value can be combined with any other unique point or value or combined with other lower or upper limits to form a range that is not explicitly specified.

[0017] Unless otherwise indicated, the term consists substantially of means that the object in question (e.g., a composition, method, or structure) may include additional elements (e.g., components, steps, and / or portions) in addition to the elements described, provided that the additional elements (e.g., components, steps, and / or portions) do not substantially alter the essential and new characteristics of the object in question (e.g., a composition, method, or structure). Thus, depending on the particular case, the term consists substantially of preferably means that the vast majority (e.g., 90% or more, such as 95% or more, particularly 99% or more, and even more particularly 99.5% or more) of the object in question is composed of Petition 870250088113, dated 09 / 29 / 2025, page 16 / 50 / 34 elements described, including entirely (i.e., 100%) consisting of the elements described.

[0018] Unless otherwise indicated, each individual point or value between the endpoints of a range is included in the range. For example, a range from 1 to 5 includes the values ​​1, 1.5, 2, 2.75, 3, 3.80, 4, 5, and so on. Furthermore, the disclosure of a range includes the disclosure of all sub-ranges included within the broader range. For example, a range from 1 to 5 includes the sub-ranges 1 to 4, 1.5 to 4.5, 1 to 2, etc. Thus, each individual point or value can serve as a lower or upper limit to match any other individual point or value or any other lower or upper limit, and the resulting range is explicitly disclosed in this application.

[0019] As used here, the term "or" is inclusive. That is, the sentence "A or B" means A, B, or both of A and B, which can also be abbreviated as A and / or B. More specifically, any of the following conditions satisfies the "A or B" condition: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist). In contrast, the exclusive "or" is represented here, for example, by the terms "either A or B" and "one of A or B".

[0020] When used in the context of a coating applied over a surface or substrate, the term "over" includes coatings that are applied directly or indirectly to the surface or substrate. Therefore, for example, a coating applied over a primer coating on a substrate constitutes a coating applied over the substrate.

[0021] The term anticorrosive coating composition refers to a coating composition that, when applied to a metallic substrate in one or more layers, a coating formed from the coating composition can be exposed to corrosive conditions (e.g., salt spray exposure for three, five or more weeks) for a Petition 870250088113, dated 09 / 29 / 2025, p. 17 / 50 / 34 considerable period of time without deterioration or corrosion or unsightly visible expansion.

[0022] As used herein, the term hydroxy-functional means the presence of at least one unreacted hydroxyl functional group.

[0023] As used herein, the meanings of the terms hydrophilic curing agent and non-hydrophilic curing agent are well known in the art. Generally, non-hydrophilic curing agents (also called hydrophobic curing agents or oily curing agents) are difficult to mix uniformly with water or aqueous components and are prone to phase separation. For example, non-hydrophilic curing agents include most unmodified polyisocyanates. The hydrophilic curing agent is generally obtained by hydrophilic modification of the curing agent. The hydrophilic curing agent may be, for example, modified non-ionic hydrophilic (e.g., Bayhydur series available from Covestro), modified ionic, non-ionic, and modified ionic composite.

[0024] The terms preferred and preferred and any other variations thereof are used to refer to embodiments of the present application that may provide certain advantages under certain circumstances. Under the same or other circumstances, however, other embodiments may be preferred. Furthermore, the description of one or more preferred embodiments does not in any way indicate that other embodiments should be unusable, and is not intended to exclude other embodiments from the scope of the invention.

[0025] Unless otherwise indicated, the methods or processes described herein are carried out under standard environmental conditions well known in the art. For example, they can be carried out at 25 °C, 101,325 Pa and a relative humidity (RH) of 40% to 80% (e.g., 50% or 60%). Two-component coating composition

[0026] Two-component coating composition according to Petition 870250088113, dated 29 / 09 / 2025, page 18 / 50 / 34, with the first aspect of the present application comprising a component A comprising at least one hydroxy-functional polyurethane dispersion and an anti-rust pigment, and a component B comprising a non-hydrophilic isocyanate curing agent, and component A has a fineness change rate after 14 days at 40 °C of 10% or less relative to an initial fineness of component A, and the fineness is measured with a fineness plate in accordance with standard GB / T 1724-2019.

[0027] After thorough study and screening, the inventors surprisingly discovered that the rate of change of fineness of component A comprising an anti-rust pigment has a significant effect on the performance of the coating composition. In this revelation, by measuring the rate of change of fineness using suitable conditions, the measurement conditions described herein can not only accurately characterize the rate of change of fineness, but also ensure no excessive time consumption while keeping the coating system substantially stable, so that the measurement process can be conveniently and easily performed in practical industrial applications. The ionic stability of anti-rust pigments can be determined by the rate of change of fineness after 14 days at 40 °C relative to the initial fineness. A relatively low rate of change of fineness is desirable.In some embodiments, the rate of change of fineness may be about 9% or less, preferably about 8% or less, more preferably about 7% or less, and even more preferably about 6% or less. For example, the rate of change of fineness may be about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less.

[0028] Hydro-functional polyurethane dispersions preferably have a higher hydroxyl value. In some embodiments, the hydroxy-functional polyurethane dispersion may have a hydroxyl value of Petition 870250088113, dated 09 / 29 / 2025, p. 19 / 50 / 34 approximately 40 to approximately 200 mg of KOH / g, preferably approximately 60 to approximately 150 mg of KOH / g, more preferably approximately 80 to approximately 120 mg of KOH / g. For example, a hydro-functional polyurethane dispersion may have a hydroxyl value of approximately 60 mg KOH / g, approximately 70 mg KOH / g, approximately 80 mg KOH / g, approximately 90 mg KOH / g, approximately 100 mg KOH / g, approximately 110 mg KOH / g, approximately 120 mg KOH / g, approximately 130 mg KOH / g, approximately 140 mg KOH / g, approximately 150 mg KOH / g, or approximately 180 mg KOH / g.

[0029] The hydroxy-functional polyurethane dispersion has a minimum film-forming temperature preferably greater than or equal to 16 °C, more preferably from 18 to 60 °C, and even more preferably from 25 to 50 °C. For example, the hydroxy-functional polyurethane dispersion has a minimum film-forming temperature of about 20 °C, about 30 °C, about 35 °C, about 40 °C, or about 45 °C.

[0030] In some embodiments, the hydroxyfunctional polyurethane dispersion has a Brookfield viscosity at 25 °C of 500 to 5,000 mPa^s. Preferably, the hydroxyfunctional polyurethane dispersion has a Brookfield viscosity at 25 °C of 800 mPa^s or higher, or 4800 mPa^s or lower. For example, the hydroxyfunctional polyurethane dispersion may have a Brookfield viscosity at 25 °C of 1000 mPa^s, 1500 mPa^s, 2000 mPa^s, 2500 mPa^s, 3000 mPa^s, 3500 mPa^s, 4000 mPa^s, or 4500 mPa^s. The Brookfield viscosity can be measured by a method known in the art using known instruments. For example, Brookfield viscosity can be measured at 25°C using Brookfield LV, 61# at 30 rpm according to GB / T2794-2013 or DIN 53019.

[0031] In some embodiments, the hydroxyfunctional polyurethane dispersion has an average particle size of 10 to 80 nm. Preferably, the hydroxyfunctional polyurethane dispersion has an average particle size of about 20 nm to 70 nm, more preferably about 25 nm. Petition 870250088113, dated 09 / 29 / 2025, p. 20 / 50 / 34 to 60 nm. For example, hydroxy-functional polyurethane dispersion has an average particle size of about 20 nm, about 30 nm, about 40 nm, about 50 nm, about 60 nm, or about 70 nm. The average particle size can be measured by a method known in the art using known instruments. For example, laser correlation spectroscopy (LKS) can be used to determine the average particle size.

[0032] In some embodiments, the hydroxyfunctional polyurethane dispersion used to formulate component A has a non-volatile content of about 20 to 60%, preferably about 30 to 50%. For example, the hydroxyfunctional polyurethane dispersion used to formulate component A may have a non-volatile content of about 25%, 30%, 35%, 40%, 45% or 50%.

[0033] In some embodiments, based on the total weight of component A, the hydroxy-functional polyurethane dispersion is present in an amount of 40% by weight to 80% by weight, preferably 45% by weight to 75% by weight, more preferably 50% by weight to 70% by weight. For example, based on the total weight of component A, the hydroxy-functional polyurethane dispersion may be present in an amount of 50% by weight, 55% by weight, 60% by weight, 65% by weight or 70% by weight.

[0034] Preferably, the hydroxy-functional polyurethane dispersion in the present application is obtained by reacting a compound having a hydroxyl functional group with a compound having an NCO functional group. Suitable hydroxy-functional polyurethane resins that can be used are prepared, for example, by reacting isocyanate-reactive compounds with polyisocyanates having at least 2 free isocyanate groups per molecule. High molecular weight polyols can be used as isocyanate-reactive compounds. Examples of polyols may include polyester polyols, polyether polyols, polycarbonate polyols, and polyols of Petition 870250088113, dated 09 / 29 / 2025, page 21 / 50 / 34 polyurethane. Preferably, polyester polyols, polyether polyols, polycarbonate polyols, or any combination thereof having a molecular weight of, for example, 500 g / mol to 6000 g / mol are used. Examples of useful polyisocyanates include terapenyl diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. In the reaction mixture, the molar equivalent ratio of NCO / OH functional groups can be from 0.2:1 to 5:1.

[0035] Preferably, the hydroxy-functional polyurethane dispersion in the present application has a relatively narrow molecular weight distribution. In some embodiments, the hydroxy-functional polyurethane dispersion may have an average particle size of about 10 nm to 80 nm, preferably about 15 nm to 70 nm, and more preferably 20 nm to 50 nm. For example, the hydroxy-functional polyurethane dispersion may have an average particle size of about 25 nm, 30 nm, 35 nm, 40 nm or 45 nm.

[0036] For ease of understanding only, some of the preferred hydroxy-functional polyurethane dispersions in this application may be briefly represented by formula (a) below. As can be seen from formula (a), in these preferred hydroxy-functional polyurethane dispersions, the hydroxyl groups are substantially located at the end of the segment. This is different from other hydroxy-functional resins in the art in which some hydroxyl groups are located on the side chains of the segments (e.g., represented by the following formula (b)). Petition 870250088113, dated 09 / 29 / 2025, page 22 / 50 12 / 34 Soft monomer - - in Segment Segment Hard group Soft group Hydroxyl Monomer Hard hydroxyl monomer Formula (a) Formula (b)

[0037] Furthermore, in the hydroxy-functional polyurethane dispersions described herein, the hydroxyl groups preferably comprise primary hydroxyl groups and, more preferably, consist substantially of primary hydroxyl groups. In some exemplary embodiments, 90% or more of the hydroxyl groups in the hydroxy-functional polyurethane dispersion are primary hydroxyl groups.

[0038] The inventors have discovered that aqueous hydroxyl-terminated polyurethane dispersions have advantages including, for example, adjustable ratio of soft and hard segments, easy molecular structure design, good compatibility with non-hydrophilic isocyanate curing agents, and excellent appearance and mechanical properties of the coating film. In particular, the inventors have discovered that by combining the aqueous hydroxyl-terminated polyurethane dispersion described herein with an anti-rust pigment (in particular the anti-rust pigments described herein), the resulting component A has a very low rate of fineness change. The inventors have also surprisingly discovered that the component A with the very low rate of fineness change described herein allows the resulting cured coating to have improved salt spray resistance, weather resistance, and chemical resistance, while maintaining excellent mechanical properties and adhesion.

[0039] In some embodiments, the hydroxyfunctional polyurethane dispersion may be a polyester-type polyurethane dispersion. Examples Petition 870250088113, dated 09 / 29 / 2025, p. 23 / 50 / 34 of a hydroxy-functional polyurethane dispersion includes, but is not limited to, Bayhydrol U XP 2755 next to Covestro. The hydroxy-functional polyester polyurethane dispersion described herein has enhanced hydrolysis resistance, good mechanical properties and placement stability, and can be applied in complex outdoor environments (humidity, high temperature, salt spray, etc.).

[0040] In some embodiments, based on the total weight of component A, the rust inhibitor is present in an amount of 2% by weight to 20% by weight, preferably 5% by weight to 15% by weight, more preferably 5% by weight to 10% by weight. For example, based on the total weight of component A, the rust inhibitor is present in an amount of 3% by weight, 4% by weight, 6% by weight, 8% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight or 20% by weight.

[0041] In some embodiments, the rust-preventing pigment is or contains silica subjected to calcium ion exchange. The rust-preventing pigment may have a calcium content of 0.5% by weight to 15% by weight, preferably 1% by weight to 12% by weight, and more preferably 3% by weight to 10% by weight, on a dry basis. For example, the calcium content in the rust-preventing pigment is 2% by weight, 4% by weight, 6% by weight or 8% by weight, on a dry basis.

[0042] In some embodiments, the anti-rust pigment itself (preferably silica itself subjected to calcium ion exchange) releases little or no Zn during acid washing or water washing for 1 hour. No Zn element can be detected by ICP-OES in the liquid obtained after acid washing or water washing with anti-rust pigment for 1 hour. For example, after acid washing and / or water washing with anti-rust pigment for 1 hour, the Zn concentration in the liquid obtained does not exceed 10.0 mg / kg. Preferably, after washing with Petition 870250088113, dated 09 / 29 / 2025, page 24 / 50 / 34 water of the anti-rust pigment for 1 hour, no Zn element is detected by ICP-OES in the liquid obtained. Preferably, after acid washing of the anti-rust pigment for 1 hour, no Zn element is detected by ICP-OES in the liquid obtained.

[0043] In some embodiments, after washing the anti-rust pigment itself (preferably the silica itself subjected to calcium ion exchange) with water for 1 hour, the resulting liquid has a Ca concentration not greater than about 1600 mg / kg, more preferably not greater than about 1000 mg / kg, and even more preferably not greater than about 800 mg / kg. Preferably, after washing the anti-rust pigment itself (preferably the silica itself subjected to calcium ion exchange) with water for 1 hour, the resulting liquid has a Ca concentration of about 50 mg / kg to 700 mg / kg.For example, after washing the anti-rust pigment itself (preferably silica subjected to calcium ion exchange) with water for 1 hour, the resulting liquid has a Ca concentration of approximately 700 mg / kg, approximately 600 mg / kg, approximately 500 mg / kg, approximately 400 mg / kg, approximately 300 mg / kg, approximately 200 mg / kg, approximately 100 mg / kg, or approximately 50 mg / kg.

[0044] Reference can be made to standard GB / T 23991-2009, Determination of the content of soluble harmful elements in coatings, wherein the sample is extracted with a solution of 0.07 mol / L hydrochloric acid and DI water (deionized water) for 1 hour in a constant temperature oscillating water bath at 37 °C and then a clear solution is obtained after filtration and the elements (such as Zn and Ca) in the clear solution are analyzed by ICP-OES.

[0045] In some embodiments, the rust-resistant pigment (preferably silica itself subjected to calcium ion exchange) has an oil absorption value of 20 g / 100 g 100 g / 100 g. Preferably, the Petition 870250088113, dated 29 / 09 / 2025, page 25 / 50 / 34: The anti-rust pigment has an oil absorption value of 90 g / 100 g or less, more preferably 80 g / 100 g or less. For example, the anti-rust pigment (preferably silica itself subjected to calcium ion exchange) has an oil absorption value of 20 g / 100 g, 30 g / 100 g, 40 g / 100 g, 50 g / 100 g, 60 g / 100 g, 70 g / 100 g, 80 g / 100 g or 90 g / 100 g. The oil absorption value of the anti-rust pigment can be determined by methods known in the art, for example, according to DIN ISO 787-5.

[0046] In some embodiments, the rust-preferably silica itself subjected to calcium ion exchange) has a particle size of 1.8 μm to 20 μm. Preferably 2.5 to 6 gm, and more preferably 2.7 to 5 gm. For example, the rust-preferably pigment has a particle size of about 2.3 gm, 2.6 gm, 3.0 gm, 3.5 gm, 4 gm or 4.5 gm.The particle size of the anti-rust pigment can be measured using the Malvern 3000E laser particle size analyzer.

[0047] In some embodiments, the rust-preferably silica itself subjected to calcium ion exchange) has a pH of 7 to 10, preferably 8.0 to 10, more preferably 8.5 to 10.0. For example, the rust-preferably pigment has a pH of about 8.5, 8.8, 9, 9.3, 9.5 or 9.8. The pH of the rust-preferably pigment can be determined in a 10% by weight aqueous suspension. The pH of the rust-preferential pigment can be determined by methods known in the art, for example, according to DIN EN ISO 787-9.

[0048] The inventors discovered that traditional anti-rust pigments often involve highly toxic substances (such as red lead, lead powder, chromate, etc.), which not only pollute the environment but also harm human health. Some anti-rust products use zinc-rich primer, phosphate-based anti-rust pigment, chromate-based anti-rust pigment, borate-based anti-rust pigment, etc. However, zinc-rich primer generally has high Petition 870250088113, dated 09 / 29 / 2025, page 26 / 50 / 34 quantity of zinc powder, which can be up to 85% or 95%. As a result, when the zinc-rich primer paint film is undergoing electric welding and oxy-fuel cutting operations, a large amount of zinc will be released and overflow, and the generated vapor will cause serious health damage to operators who can easily develop a disease called metal fume fever. Most phosphate, chromate, and borate-based anti-rust pigments are insoluble and have poor dispersion in water-based coatings, leading to poor anti-rust performance when these anti-rust pigments are used alone. The inventors found that silica subjected to calcium ion exchange presents advantages, including absence of heavy metals, absence of toxicity, absence of pollution, good stability, among others.Without delving too deeply into theory, silica subjected to calcium ion exchange can promote the formation of insoluble silicates with stable chemical properties in coating systems, and these insoluble silicates can migrate to the metal surface to form a passivation layer, thus preventing the electrochemical reaction on the metal surface and inhibiting the corrosion process of the metals.

[0049] In addition to silica subjected to calcium ion exchange, component A may further comprise other anti-rust pigments. In some embodiments, component A comprises one or more of wollastonite, strontium phosphate, zinc phosphate, and zinc oxide. The inventors have surprisingly discovered that the salt spray resistance, acid resistance, and weather resistance of the coating can be significantly improved by employing a combination of specific anti-rust pigments. The combination of one or more of wollastonite, strontium phosphate, zinc phosphate, and zinc oxide with silica subjected to calcium ion exchange produces a synergistic effect, and the resulting coating performance is apparently much better than using a certain anti-rust pigment alone. Unintentionally Petition 870250088113, dated 09 / 29 / 2025, page 27 / 50 / 34, adhering to the theory, silica subjected to calcium ion exchange can not only promote the formation of insoluble silicate with stable chemical properties, but can also combine with the metal oxide film to form a composite protective layer, which can quickly solve the problem related to salt spray, prevent foam formation, have high weather resistance, and improve the hardness of the coating film. In particular, the inventors found that combining wolastonite with silica subjected to calcium ion exchange can significantly increase the synergistic effect. In some preferred embodiments, component A comprises from 2% to 20% by weight of silica subjected to calcium ion exchange and from 3% to 20% by weight of wolastonite.More preferably, component A comprises from 4% by weight to 10% by weight of silica subjected to calcium ion exchange and from 4% by weight to 8% by weight of wollastonite.

[0050] The two-component coating composition, preferably component A, may further comprise a silane coupling agent. In some embodiments, the coupling agent comprises a silane compound having Formula I: Xi X1---Si—Y1Xi Formula (I) where each X1 is independently selected from a group consisting of -Cl, -OCH3, -OCH2CH3, -OC2H4OCH3, -OSi (CH3)3 and OCOCH3; and

[0051] Y1 is an alkyl group terminated by -Cl, -NH2, -SH, -OH, epoxy group, -N3Y-methacryloxypropyl or isocyanate.

[0052] In some embodiments, the silane coupling agent has a molecular weight of 100 Dalton to 800 Dalton, preferably 200 Dalton to 400 Dalton, for example, about 150 Dalton, about 250 Dalton, Petition 870250088113, dated 09 / 29 / 2025, page 28 / 50 / 34 300 Daltons.

[0053] Preferably, the silane coupling agent is an epoxy silane coupling agent. For example, in Formula I, Yi is an alkyl group terminated by the epoxy group.

[0054] The inventors discovered that, on the one hand, the silane coupling agent has the active group that can react with metal oxide on the metal surface or water on the surface to form hydrogen bonds, which improves the adhesion of the coating to the metal substrate; on the other hand, the silane coupling agent can further promote the function of the anti-rust pigment in the coating composition and improve the salt spray resistance and acid resistance of the coating. Especially when an epoxy silane coupling agent is used, the benefits of these two aspects are more prominent.

[0055] Most importantly, in some embodiments, the beneficial effects described above can be observed by adding a smaller amount of the silane coupling agent. Based on the total weight of component A, the silane coupling agent is present in an amount of 0.2% by weight to 2% by weight, preferably 0.3% by weight to 1.8% by weight, more preferably 0.5% by weight to 1.5% by weight. For example, the amount of the silane coupling agent may be about 0.4% by weight, about 0.5% by weight, about 0.6% by weight, about 0.8% by weight, about 1.0% by weight, or about 1.2% by weight.

[0056] In the two-component coating composition according to the present application, component A may additionally comprise an additive. These additives do not adversely affect the two-component coating composition or the cured coating obtained therefrom. Suitable additives include, for example, those that improve the processability or manufacturing properties of the composition, enhance the aesthetic feel of the composition, improve the Petition 870250088113, dated 09 / 29 / 2025, page 29 / 50 / 34 specific functional properties or characteristics (such as adhesion to the substrate) of the coating composition or the cured composition obtained from it, or reduce the cost. Additives that may be included are, for example, pigments, lubricants, film-forming aids, wetting agents, plasticizers, defoamers, colorants, antioxidants, flow control agents, thixotropic agents, matting powders, dispersants, adhesion promoters, thickeners, pH regulators, light stabilizers, flash rust inhibitors, cure promoters, or combinations thereof. The quantity of each optional ingredient is sufficient for the intended purpose, but preferably, this quantity does not negatively affect the two-component coating composition or the cured coating obtained from it.In some preferred embodiments, component A may comprise conventional additives such as a foam eliminator, a dispersant, a leveling agent, a light stabilizer, an instant rust inhibitor, a thickener, or any combination thereof. According to the present application, the total quantity of conventional additives is from 0.3% by weight to 20% by weight, preferably from 0.5% by weight to 18% by weight, for example, about 10% by weight, relative to the total weight of component A. In some embodiments, the quantity of dispersant may be from 0.1% by weight to 2% by weight, the quantity of defoamer may be from 0.1% by weight to 0.8% by weight, the quantity of leveling agent may be from 0.1% by weight to 2% by weight, the quantity of light stabilizer may be from 0.5% by weight to 3% by weight and / or the quantity of instant rust inhibitor may be from 0.1% by weight to 1% by weight.

[0057] Examples of light stabilizers may include, but are not limited to, hindered amine compounds, hindered phenolic compounds; CHIMAS0RB 944, TINUVIN 144, TINUVIN 292, TINUVIN 770, Petition 870250088113, dated 09 / 29 / 2025, p. 30 / 50 / 34 IRGANOX 1010, IRGANOX 1098 (trade names, available from Ciba Specialty Chemicals KK respectively) etc.

[0058] In some embodiments, component A may additionally comprise pigments other than the rust-preventing pigments described above. The pigments may be spherical, fibrous, flaky, or otherwise regular or irregular in shape with sizes ranging from microns to nanometers. Examples of pigments include metal oxides such as titanium dioxide, iron oxide, zirconia, alumina; hybrid metal oxides of two or more metals, including manganese, nickel, titanium, chromium, antimony, magnesium, cobalt, iron, or aluminum; oxymetallic compounds such as bismuth vanadate, cobalt aluminate, cobalt zincate; pigments with metallic effects such as aluminum sheets, copper, and copper-zinc alloys; pearlescent pigments such as lead carbonate and bismuth oxychloride; talc; and any combination thereof. Preferably, the pigment is titanium dioxide and / or iron oxide.

[0059] Based on the total weight of component A, the total quantity of pigments other than the rust inhibitor pigment as described above can be from 0% by weight to 40% by weight, as from 1% by weight to 35% by weight, from 2% by weight to 30% by weight, from 3% by weight to 25% by weight, from 4% by weight to 20% by weight, or from 5% by weight to 15% by weight. More preferably, based on the total weight of component A, the quantity of each pigment is independently from 0% by weight to 40% by weight, from 1% by weight to 30% by weight, from 2% by weight to 20% by weight, from 3% by weight to 15% by weight, or from 4% by weight to 10% by weight.

[0060] In some embodiments, the dispersion medium (solvent or carrier fluid) in component A comprises fundamentally or mainly water. For example, in some embodiments, the dispersion medium in component A comprises at least about 50% by weight, preferably at least about 60% by weight, more preferably by Petition 870250088113, dated 09 / 29 / 2025, page 31 / 50 / 34 less than 70% by weight and at most about 99% by weight, at most about 100% by weight of water, based on the total weight of the dispersion medium. For example, based on the total weight of the dispersion medium, the dispersion medium contains about 80% by weight, about 85% by weight or about 95% by weight of water.

[0061] The two-component coating compositions of the present application may have relatively fewer volatile components. In some embodiments, based on the total weight of component A, component A comprises from 0% by weight to 15% by weight, preferably from 0% by weight to 12% by weight of a solvent (in particular an organic solvent). For example, based on the total weight of component A, component A comprises about 2% by weight, 5% by weight, 7% by weight, 10% by weight of a solvent (in particular an organic solvent).Examples of organic solvents include monohydric or polyhydric alcohols, such as propanol, butanol, hexanol, benzyl alcohol; diol ethers or esters, such as diethylene glycol dialkyl ethers, dipropylene glycol dialkyl ethers, ethoxypropanol, and butyl ethylene glycol, each having a C1-C6 alkyl group; diols, such as ethylene glycol and propylene glycol; and ketones, such as methyl ethyl ketone, acetone, cyclohexanone; N-methylpyrrolidone, methylpyrrolidone; aromatic or aliphatic hydrocarbons, such as toluene, xylene, or linear or branched C6-C12 aliphatic hydrocarbons. In some embodiments, the organic solvent comprises dipropylene glycol butyl ether, propylene glycol diacetate, propylene glycol methyl ether acetate, or any combination thereof.

[0062] In some modalities, based on the total weight of component A, component A comprises: 40% to 80% by weight of hydroxy-functional polyurethane dispersion, 2% to 20% by weight of anti-rust pigment, Petition 870250088113, dated 09 / 29 / 2025, page 32 / 50 / 34 of 0.2% by weight to 2% by weight of silane coupling agent, 0.3% by weight to 20% by weight of an additive, 0% by weight to 15% by weight of a solvent.

[0063] In the two-component coating composition described herein, component B comprises a non-hydrophilic isocyanate curing agent. In some embodiments, the non-hydrophilic isocyanate curing agent comprises aliphatic diisocyanate, aromatic diisocyanate, cycloaliphatic diisocyanate, or any combination thereof. Preferably, the non-hydrophilic isocyanate curing agent comprises aliphatic diisocyanate.

[0064] Preferably, the non-hydrophilic isocyanate curing agent has an NCO content in the range of 10% by weight to 30% by weight. Preferably, the NCO content is in the range of 15% by weight to 25% by weight. For example, the NCO content may be 18% by weight, 21% by weight, 22% by weight, 23% by weight or 24% by weight. The NCO content may be determined in accordance with DIN EN ISO 11909.

[0065] Preferably, a non-hydrophilic isocyanate curing agent with low viscosity is used. For example, the non-hydrophilic isocyanate curing agent has a viscosity at 23 °C of less than 4000 mPa^s. More preferably, the non-hydrophilic isocyanate curing agent has a viscosity at 23 °C of less than 3800 mPa^s. For example, a non-hydrophilic isocyanate curing agent may have a viscosity at 23 °C of 730 mPa^s, 1000 mPa^s, 1500 mPa^s, 2000 mPa^s, or 3000 mPa^s. The viscosity as described above can be measured according to DIN EN ISO 3219 / A.3.

[0066] The non-hydrophilic isocyanate curing agent may be in the form of an oligomer or homopolymer. The oligomer or homopolymer may contain 2 to 8 units Petition 870250088113, dated 09 / 29 / 2025, page 33 / 50 / 34 monomeric. For example, the non-hydrophilic isocyanate curing agent may be a trimer.

[0067] Examples of the non-hydrophilic isocyanate curing agent include isocyanate curing agents based on hexamethylene diisocyanate (HDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), xylylene diisocyanate (XDI) or tetramethyl m-xylylene diisocyanate (TMXDI).

[0068] In some preferred embodiments, the aliphatic diisocyanate is an aliphatic diisocyanate based on hexamethylene diisocyanate (HDI), particularly preferably an HDI trimer. Preferably, the aliphatic diisocyanate may comprise one or more of an asymmetric trimer, a symmetric trimer, and a homopolymer that are based on HDI. Commercially available isocyanate curing agents, such as DESMODUR N 3300, 3600, and 3900, may be used.

[0069] The non-hydrophilic isocyanate curing agent may be used alone or in combination. In some embodiments, the non-hydrophilic isocyanate curing agent may further comprise a combination of two or more of the curing agents described above. For example, in an exemplary embodiment, DESMODUR N 3300, 3600 and 3900 may be used in a weight ratio of 1:1:1 as non-hydrophilic isocyanate curing agents.

[0070] Component B may or may not contain a hydrophilic isocyanate curing agent.

[0071] In some embodiments, component B comprises a hydrophilic isocyanate curing agent. The hydrophilic isocyanate curing agent may be prepared by modification in a manner known in the art. Examples of hydrophilic isocyanate include, but are not limited to, isophorone diisocyanate (IPDI)-based hydrophilic isocyanates and HDI-type isocyanates.

[0072] In some modalities, the weight ratio between the agent of Petition 870250088113, dated 09 / 29 / 2025, page 34 / 50 / 34 The ratio of non-hydrophilic isocyanate curing agent to hydrophilic isocyanate curing agent is in the range of 99:1 to 5:95. Preferably, the weight ratio between the non-hydrophilic isocyanate curing agent and the hydrophilic isocyanate curing agent is in the range of 90:10 to 10:90, more preferably 80:20 to 20:80. For example, the weight ratio between the non-hydrophilic isocyanate curing agent and the hydrophilic isocyanate curing agent is 90:10, 70:30, 50:50, 30:70 or 10:90.

[0073] In the two-component polyurethane coating composition described herein, component B comprises a diluent. The diluent may comprise at least one solvent with a low boiling point. In this context, boiling point has a general meaning as understood by those skilled in the art. Boiling point is understood to be the temperature at which a liquid boils at atmospheric pressure (i.e., 1 bar), that is, the temperature at which the saturated vapor pressure of the liquid equals the external pressure. The boiling point value of the compounds can be obtained from scientific and technological literature or reference books.

[0074] Preferably, the low-boiling-point solvent has a boiling point of 160 °C or less. For example, the low-boiling-point solvent includes one or more of the following: propylene glycol monomethyl ether acetate (PMA), dipropylene glycol dimethyl ether (DMM), methyl ethyl ketone (MEK), acetone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, trimethylbenzene, naphtha solvent 100#, 2-methylpropanol acetate (MPA), and n-butyl acetate (BAC). More preferably, the low-boiling-point solvent is PMA, MEK, or a combination of both.

[0075] In some preferred embodiments, the weight ratio between the diluent and the non-hydrophilic curing agent is 30:70 to 90:10. More preferably, the weight ratio between the diluent and the non-hydrophilic curing agent is 40:60 to 85:15. For example, the weight ratio between the diluent Petition 870250088113, dated 09 / 29 / 2025, page 35 / 50 / 34 and the non-hydrophilic curing agent can be 45:65, 50:50, 55:45, 60:40, 70:30 or 80:20.

[0076] In the two-component polyurethane coating composition described herein, the relative amounts of component A and component B can be adjusted as desired. In some embodiments, the mass ratio between component A and component B is 1:1 to 10:1, preferably 1:1 to 10:1, more preferably 2:1 to 8:1, such as 3:1, 4:1, 5:1, 6:1, 7:1.

[0077] According to the present application, a two-component coating composition can be prepared simply by mixing component A and component B in a predetermined ratio in a mixing device before application. The resulting coating composition can be applied using a variety of methods familiar to those skilled in the art, including spraying (e.g., air-assisted, airless, or electrostatic spraying), brush coating, roller coating, overflow coating, and impregnation. In one embodiment of the present application, the mixed coating composition is applied by spraying. The coating composition can be applied in various wet film thicknesses. In embodiments of the present application, the wet film thickness preferably provides a dry film thickness of about 40 μm to about 260 μm and, more preferably, of about 50 μm to about 150 μm.The applied coating can be cured by air drying or by accelerating the cure using various drying devices (e.g., ovens) familiar to those skilled in the art. Process for preparing a two-component coating composition

[0078] A second aspect of the present application provides a process for preparing a two-component coating composition comprising mixing a component A and a component B, Petition 870250088113, dated 29 / 09 / 2025, page 36 / 50 / 34 characterized by component A comprising at least one hydroxy-functional polyurethane dispersion and an anti-rust pigment, by component B comprising a non-hydrophilic isocyanate curing agent and by component A having a fineness change rate after 14 days at 40 °C of 10% or less relative to an initial fineness of component A and the fineness being measured with a fineness plate in accordance with standard GB / T 17242019.

[0079] The content described in the context of a two-component coating composition also applies to a process for preparing a two-component coating composition. Coated article

[0080] A third aspect of the present application provides a coated article, characterized in that the coated article comprises: a metallic substrate having at least one principal surface; and the two-component coating composition as described herein or a cured coating formed therefrom, applied to at least one principal surface of the metallic substrate.

[0081] The two-component coating composition of the present application can be applied directly onto a substrate or as a topcoat. In some embodiments, the two-component coating composition of the present application can be used in conjunction with a primer. In this case, the article of the present application includes a substrate, a primer coating, and a coating formed from the two-component coating composition of the present application. In other embodiments of the present application, the two-component coating composition of the present application can be applied without a primer and applied directly onto a primary surface of a substrate. Preferably, the two-component coating composition of the present application has the two-in-one advantage of primer and topcoat, and can greatly reduce the Petition 870250088113, dated 09 / 29 / 2025, p. 37 / 50 / 34 complexity of construction, reduce investment in equipment and personnel and also has excellent coating properties (including salt spray resistance, acid resistance, adhesion, etc.).

[0082] Any suitable metallic substrate known in the art may be used as a metallic substrate for the manufacture of the article of this application. By way of example, the metallic substrate may include one or more of an iron substrate, an aluminum substrate, a copper substrate, a carbon steel, a stainless steel, an aluminum-zinc alloy, a zinc-coated steel substrate, a tin-coated steel substrate, and a phosphate plate.

[0083] Advantageously, the cured coating on the coated article described herein has one or more of the following properties: absence of bubble formation at 35 °C for at least 500 hours in the neutral salt spray test on aluminum plate, phosphate plate or both, absence of bubble formation at 20 °C for at least 120 hours in 5% sulfuric acid solution, absence of bubble formation at 20 °C for at least 120 hours in 5% sodium hydroxide solution, has a Δε of 1.0 or lower and a light retention at 60 °C greater than 80% after exposure to a xenon lamp for 1000 hours.In particular, the cured coating in the coated article described herein has a very excellent combination of properties, such as two or more properties: absence of bubble formation at 35 °C for at least 1000 hours in the neutral salt spray test on aluminum plate, phosphate plate or both; absence of bubble formation at 20 °C for at least 120 hours in 5% sulfuric acid solution; absence of bubble formation at 20 °C for at least 120 hours in 5% sodium hydroxide solution; has a ΔE of 1.0 or less; and light retention at 60 °C greater than 80% after exposure to a xenon lamp for 1000 hours. Preferably, the cured coating in the coated article described herein does not generate bubbles at 35 °C for at least... Petition 870250088113, dated 09 / 29 / 2025, p. 38 / 50 / 34 1000 hours in the neutral salt spray test on an aluminum plate, phosphate plate, or both; does not generate bubbles at 20 °C for at least 120 hours in a 5% sulfuric acid solution; does not generate bubbles at 20 °C for at least 120 hours in a 5% sodium hydroxide solution; has a Δε of 1.0 or less and light retention at 60 °C greater than 80% after exposure to a xenon lamp for 1000 hours. More preferably, the cured coating in the coated article described herein does not generate bubbles at 35 °C for at least 1000 hours, or even more preferably, at least 1100 hours, in a neutral salt spray test on an aluminum plate, a phosphate plate, or both. For example, the cured coating on the coated article described herein does not generate bubbles at 35 °C for at least 1200 hours in a neutral salt spray test on an aluminum plate, a phosphate plate, or both.The inventors believe that such an excellent combination of performance, as described herein, could not have been achieved prior to the present application and goes beyond the knowledge and ability of those skilled in the art.

[0084] According to the present application, the coated article can be prepared, for example, by the following steps: (1) providing a polished metallic substrate; (2) employing an application process, sequentially applying and forming one or more layers of the coating composition described herein on the metallic substrate and curing to obtain a cured coating.

[0085] The metal articles of this application may be used for the following end applications, including but not limited to, refrigerated containers and non-refrigerated shipping containers (e.g., dry cargo containers) from suppliers or manufacturers including China International Marine Containers (CIMC), Graaff Transportsystem GmbH, Maersk Line and other suppliers or manufacturers well known to those skilled in the art; chassis, trailers (including semi-trailers), vehicles Petition 870250088113, dated 09 / 29 / 2025, page 39 / 50 / 34 railways, truck bodies, ships, bridges, petrochemical tank walls, building skeletons and prefabricated or existing metal parts that require temporary internal or external corrosion protection during manufacturing. Additional uses include metal corners, passageways, beams (e.g., I-beams), conduits, pipes, plates or other components that can be welded to these or other metal parts. Examples

[0086] The following examples are intended to describe the present application more specifically, merely for illustrative purposes. Various modifications and variations within the scope of the present application are evident to those skilled in the related art. Unless otherwise indicated, all portions, percentages, and ratios reported in the following examples are based on weight. In addition, all reagents used in the examples are commercially available and can be used directly without further treatment. Testing methods

[0087] Gloss: The 60° gloss was evaluated according to ASTM D523 using a Sheen Hole Gloss Meter.

[0088] Rate of change of grinding fineness: The initial fineness before storage and the fineness after storage were measured after 14 days of storage at 40 °C. The rate of change of fineness after 14 days at 40 °C relative to the initial fineness was calculated. Fineness was measured using a fineness plate according to GB / T 1724-2019.

[0089] Pencil Scratch Hardness: Pencil scratch hardness was evaluated according to ASTM D3363 standard. Data were reported as pencil scratch hardness for the last successful test before coating breakage. Thus, for example, if the coating does not break when tested with a 2H pencil, but breaks when tested with a 3H pencil, the coating is reported as having a pencil scratch hardness of 2H. Petition 870250088113, dated 09 / 29 / 2025, pages 40 / 50 / 34

[0090] Impact resistance: The impact resistance of the coating film was determined in accordance with standard GB / T 1732-2020.

[0091] Adhesion: Adhesion was measured according to GB / T3324-2017 (grid method). Ten (10) groups of cross-grids were drawn with a spacing of approximately 2 mm using a notching knife, then transparent tape was used to stick to the notch surface, compacted and peeled off. Pigment exfoliation in grids was evaluated on a scale of 0 to 5 degrees. Degree 0 represented the best and degree 5 represented the worst.

[0092] Moisture and heat resistance: The moisture and heat resistance of the coating films was measured in accordance with GB / T 1740-2007.

[0093] Salt spray resistance: The salt spray resistance of the coating film was determined according to GB / T 17712007. A peel width of less than 2.5 mm was required.

[0094] Chemical resistance: The sample was immersed in 5% sulfuric acid, 5% sodium hydroxide, gasoline or light oil according to GB 9274-1988 at 20±1 °C, then observed for blistering, cracking, peeling, and other unsatisfactory states. The last time no adverse states were observed was recorded.

[0095] Weather resistance: measured using an artificial aging machine with a xenon lamp for 1000 h, with light loss and color difference within grade 1, see national standard GB / T 1865-2009 Paints and varnishes - Artificial weathering and exposure to artificial radiation. Exposure to filtered xenon arc radiation.

[0096] Concentration of elements in the clear solution after washing with water or washing pigments with acid: measured in accordance with standard GB / T 23991-2009 Determination of the content of harmful soluble elements in coatings by extracting a sample with an acid solution Petition 870250088113, dated 09 / 29 / 2025, page 41 / 50 / 34 hydrochloric acid 0.07 mol / L and DI water (deionized water), respectively, for 1 hour in a constant temperature oscillating water bath tank at 37 °C and then filtering to obtain a clear solution, followed by elemental analysis (such as Zn and Ca) in the clear solution by ICP-OES. Examples 1 to 8

[0097] The two-component coating compositions of Examples 1 to 8 and Comparative Examples 1 were prepared. Unless otherwise indicated, Bayhydrol U XP 2755 available from Covestro was used as an aqueous dispersion of hydroxyl polyurethane and Bayhydrol A 2770 was used as an aqueous dispersion of hydroxyl polyacrylate.

[0098] The calcium ion exchange silica used did not release Zn during acid washing (or water washing) for 1 hour (no Zn element detected using ICP-OES). After water washing of the calcium ion exchange silica used for 1 hour, the clear liquid obtained had a Ca element concentration of approximately 565 mg / kg. Furthermore, the calcium ion exchange silica used had an oil absorption value of approximately 80 g / 100 g, an average particle size of approximately 3 ± 0.5 μm, and a pH of 9.3 ± 0.5 in an aqueous suspension (10% by weight).

[0099] Component A and component B were prepared separately according to the components and quantities shown in Table 1 below and mixed to obtain the two-component coating compositions.

[00100] The coating compositions obtained were applied to an aluminum plate and then cured. The properties of the coating compositions and the coatings were tested and the results are shown in Table 2 below. Petition 870250088113, dated 09 / 29 / 2025, pages 42 / 50 / 34 Table 1 Comparative example 1 1 9 ι / γ 1 ¢0 1 To oo 30 IO -f- oo ooo 30 -f- 1 TO o oo o 1 TO OI oo Example 8 30 ι / γ ι / γ O 1 το oo 30 O oooo 30 O -f- ooo oo o 1 το 04 oo Example 7 oo OO ι / γ O 1 το ι / γ O r- -f- oo o OO OO -f- oo oo o | FO 04 oo Example 6 oo OO ι / γ O 1 το ι / γ O r- -f- oo o oo o O -f- ooo oo o | FO 04 oo Example 5 oo OO ι / γ O 1 το ι / γ -f- o -f- oo o oo o O -f- ooo oo o | FO 04 oo Example 4 oo OO ι / γ O 1 το ι / γ -f- r- -f- oo o oo o O -f- ooo oo o | FO 04 oo Example 3 oo oo ι / γ O 1 το oo -f- r- -f- 30 o oo o O -f- ooooo | FO 04 oo Example 2 30 ι / γ ι / γ O 1 To oo 30 o -f- oo oo 30 o -f- ooo oo o 1 το 04 oo Example 1 30 ι / γ ι / γ O 1 το oo 30 o -f- oo oo 30 o -f- ooo oo o 1 το 04 oo Raw materials Deionized water Dispersant Foam eliminator Leveling agent Black iron oxide Silica subjected to ion exchange of calcium ions Strontium phosphate Wolastonite Zinc phosphate Zinc oxide Aqueous dispersion of hydroxyl polyurethane Aqueous dispersion ofHydroxyl acrylate Solvent 3-glycidyloxypropyltrimethoxysilane Light stabilizer Instant rust inhibitor Thickener DESMODUR 3900 Propylene glycol methyl ether acetate Component A Component B Comparative Example 1 14.5% | CO O o 30 o O 04 O 500 | 168 1 500 | 500 | 168 1 Example 8 5.0% | is CO O o OOO 500 500 0001 0001 168 Example 7 9.5% O | 617 o O CO O 500 260 0001 0001 1168 Example 6 8.5% o 30 | Z9 o O o O 500 280 0001 0001 1168 Example 5 8.0% OO OOO o O o O 500 O 30 CO oooo 168 Example 4 6.0% 30 O CO 30 | Example 3 6.0% cn O 30 | o O o O 500 550 1200 1200 168 Example 2 5.5% OO 30 O o O o O 500 009 1400 1400 1168 Example 1 5.0% | zs CO O o O o O 500 009 1400 1400 1168 Test Item | Component A Fineness Change Rate | Film Thickness | 60 Degree Brightness / Incident Angle | Hardness | Impact Resistance | Adhesion | Embedding Test | Moist Heat Resistance / h On Sanded Steel Sheet On Phosphated Plate On Aluminum Plate | Gasoline Resistance / h Neutral Salt Spray Resistance / h 13, of 29 / 09 / 2025, page 43 / 50 / 34 Comparative Example 1 168 | oo Ό Example 8 168 oo Ό Example 7 1168 oo Ό Example 6 1168 oo Ό Example 5 168 oo Ό Example 4 168 oo Ό Example 3 168 oo Ό Example 2 1168 oo Ό Example 1 1168 oo Test Item | Light Oil Resistance / h | Alkaline Resistance / h O. o 89% | 168 oo o 85% O 2 oo o 185% 1168 o χ© OO 168 oo o 88% 168 o 82% 168 o %68 1168 Ch o 188% 1168 oo o 185% | Acid resistance / hw < Light retention / 60° Weather resistance (xenon lamp 1000 h) Petition 870250088113, dated 09 / 29 / 2025, pages 44 / 50 / 34

[00101] Based on the experimental results, it can be observed that the two-component coating composition of this application can provide a coating with excellent salt spray resistance, weather resistance, mechanical properties, adhesion, and chemical resistance. Furthermore, the two-component coating composition of the patent application has the characteristics of a two-in-one primer and topcoat, simple construction, and environmental protection.

[00102] Although the present application is described with reference to numerous embodiments and examples, one skilled in the art would recognize from the disclosure of the present application that other embodiments may be devised. It will be readily apparent to those skilled in the art that modifications may be made to the embodiments of the present patent application without departing from the principles disclosed in the preceding descriptive report. For example, without departing from the principles disclosed in the previous description, the technical solutions obtained by combining multiple features or preferred implementations described herein should be understood as belonging to the contents described herein. Such modifications should be considered as included in the claims, unless expressly stated otherwise in the claims.Consequently, the embodiments described herein in detail are merely illustrative and are not intended to limit the scope of this patent application, the full scope of which is defined by the appended claims and any and all of their equivalents. Petition 870250088113, dated 09 / 29 / 2025, pp. 45 / 50

Claims

1 / 4 CLAIMS 1. Two-component coating composition, characterized in that it comprises: a component A comprising at least one hydroxy-functional polyurethane dispersion and an anti-rust pigment, and a component B comprising a non-hydrophilic isocyanate curing agent, wherein component A has a rate of change in grinding fineness after 14 days at 40 °C of 10% or less relative to an initial fineness of component A, and the fineness is measured with a fineness plate in accordance with GB / T 1724-2019.

2. Two-component coating composition according to claim 1, characterized in that the hydroxy-functional polyurethane dispersion has a hydroxyl value of 40 mg KOH / g 200 mg KOH / g.

3. Two-component coating composition according to claim 1 or 2, characterized in that the hydroxy-functional polyurethane dispersion has an average particle size of 10 nm to 80 nm.

4. Two-component coating composition according to any one of claims 1 to 3, characterized in that, based on the total weight of component A, the anti-rust pigment is present in an amount of 2% by weight to 20% by weight and the hydroxy-functional polyurethane dispersion is present in an amount of 40% by weight to 80% by weight.

5. Two-component coating composition according to any one of claims 1 to 4, characterized in that the anti-rust pigment comprises silica subjected to ion exchange of calcium ions and in that the anti-rust pigment has a calcium content of 0.5% by weight to 15% by weight, on a dry basis.

6. Two-component coating composition according to any one of claims 1 to 5, characterized in that the anti-rust pigment has an oil absorption value of 20 g / 100 g 100 g / 100 g.

7. Two-component coating composition according to any one of claims 1 to 6, characterized in that the anti-rust pigment has a particle size of 1.8 μm to 20 μm.

8. Two-component coating composition according to any one of claims 1 to 7, characterized in that the anti-rust pigment has a pH value of 7 to 10.

9. Two-component coating composition according to any one of claims 1 to 8, characterized in that component A comprises one or more of wolastonite, strontium phosphate, zinc phosphate and zinc oxide.

10. Two-component coating composition according to any one of claims 1 to 9, characterized in that component A comprises a silane coupling agent and, preferably, the silane coupling agent is an epoxy silane coupling agent.

11. Two-component coating composition according to any one of claims 1 to 10, characterized in that the weight ratio between component A and component B is in a range of 1:1 to 10:

1.

12. Two-component coating composition according to any one of claims 1 to 11, characterized in that, based on the total weight of component A, component A comprises: Petition 870250088113, dated 09 / 29 / 2025, page 47 / 50 3 / 4 of 40% by weight to 80% by weight of hydroxy-functional polyurethane dispersion, 2% by weight to 20% by weight of anti-rust pigment, 0.2% by weight to 2% by weight of silane coupling agent, 0.3% by weight to 20% by weight of an additive, 0% by weight to 15% by weight of a solvent.

13. Process for preparing a two-component coating composition, as defined in any one of claims 1 to 12, characterized in that it comprises: mixing component A and component B, wherein component A comprises at least one hydroxy-functional polyurethane dispersion and an anti-rust pigment, and component B comprises a non-hydrophilic isocyanate curing agent, and component A has a rate of change in grinding fineness after 14 days at 40 °C of 10% or less relative to an initial fineness of component A, and the fineness is measured with a fineness plate in accordance with GB / T 1724-2019.

14. Coated article, characterized in that it comprises: a metallic substrate having at least one principal surface; and a two-component coating composition, as defined in any one of claims 1 to 12, or a cured coating formed therefrom, applied to at least one principal surface of the metallic substrate.

15. Coated article according to claim 14, characterized in that the metallic substrate comprises one or more of an iron substrate, an aluminum substrate, a copper substrate, a carbon steel, a stainless steel, an aluminum-zinc alloy, a zinc-coated steel substrate, a tin-coated steel substrate and a phosphated plate.

16. Coated article according to claim 14 or 15, characterized in that the coated article has a cured coating that does not generate bubbles at 35 °C for at least 1000 hours in the neutral salt spray test, does not generate bubbles at 20 °C for at least 120 hours in a 5% sulfuric acid solution, does not generate bubbles at 20 °C for at least 120 hours in a 5% sodium hydroxide solution, has a Δε of 1.0 or less and a light retention at 60 °C greater than 80% after exposure to a xenon lamp for 1000 hours. Petition 870250088113, dated 09 / 29 / 2025, p. 49 / 50