Solvent based acid curable coating compositions and articles formed therefrom

Abstract

The invention relates to a solvent based acid curable coating composition and an article formed therefrom. The solvent type acid curing coating composition comprises at least one hydroxyl functional resin, at least one amino resin, at least one acid catalyst, at least one matting powder and an additional additive, and the at least one matting powder comprises at least one non-silica-based matting powder; the at least one non-silica-based matting powder has a core-shell structure with titanium dioxide as a core and silicon dioxide as a shell, and has a Dv50 particle size of 4-8 microns, and the particle size is determined by laser diffraction according to ISO 13320-1. The article includes a substrate having at least one major surface; the present invention relates to a solvent-based acid-curable coating composition comprising a substrate, and a base coat directly or indirectly coated on at least part of the main surface of the substrate, and a top coat directly or indirectly coated on the base coat, the top coat being formed from the solvent-based acid-curable coating composition according to the present invention.

Description

Technical Field

[0001] This invention relates to a solvent-based acid-curing coating composition. More specifically, this invention relates to a solvent-based acid-curing coating composition exhibiting excellent corrosion resistance, particularly excellent acid and alkali resistance, in complex chemical environments, and articles formed therefrom, which are particularly suitable for livestock applications. Background Technology

[0002] Pre-coated coil materials are organic / metal composite sheets produced by coating rolled metal sheets with paint, either in rolls or single sheets. Unlike general industrial coatings, coil coatings utilize a pre-coating and post-processing manufacturing process. Therefore, the coating must not only have high hardness to prevent scratches and abrasions during processing and use, but also prevent cracking during processing. This necessitates coil coatings possessing excellent overall performance. As one of the earliest coatings used in pre-coated coil materials, acid-curing (AC) coatings utilize acidic catalysts to accelerate the cross-linking and curing of amino and hydroxyl functional resins. AC coatings offer advantages such as a hard and wear-resistant film; high heat, water, and cold resistance; good transparency; good resistance to yellowing; and, compared to solvent-based two-component (2K) polyurethane (PU) coatings, are isocyanate-free. Therefore, acid-curing coating compositions have wide applications in various scenarios.

[0003] With the rapid development of industries such as animal husbandry, agriculture, healthcare, sanitation, chemicals, and papermaking, the domestic construction sector has placed higher demands on the acid and alkali resistance of coil coatings. Taking animal husbandry as an example, the accumulation and decomposition of animal excrement and the application of highly oxidizing disinfectants inevitably fill livestock sheds with various corrosive chemicals, significantly shortening the service life of livestock buildings. The other industries mentioned above also face similar challenges in dealing with complex chemical environments.

[0004] Therefore, the coatings industry urgently needs coating compositions with better resistance to strong corrosion in order to meet the application requirements in various complex chemical environments. Summary of the Invention

[0005] The present invention provides a solvent-based acid-curing coating composition comprising at least one hydroxyl-functional resin, at least one amino resin, at least one acidic catalyst, at least one matting agent, and additional additives, wherein the at least one matting agent comprises at least one non-silica-based matting agent; and wherein the at least one non-silica-based matting agent has a core-shell structure with titanium dioxide as the core and silicon dioxide as the shell, and has a Dv50 particle size of 4-8 micrometers, the particle size being determined by laser diffraction according to ISO 13320-1.

[0006] The present invention also provides an article comprising a substrate having at least one main surface; and a base coating applied directly or indirectly to at least a portion of the main surface of the substrate, and a top coating applied directly or indirectly to the base coating, wherein the top coating is formed by a solvent-based acid-curing coating composition according to the present invention. Preferably, the substrate is selected from metal substrates, and preferably includes stainless steel, iron, aluminum, aluminum alloys, or any combination thereof.

[0007] The inventors of this application disclose for the first time that, in the formulation of solvent-based acid-curing coating compositions, particularly in the formulation of acid-curing coating compositions containing at least one hydroxyl-functional resin, at least one amino compound, and at least one acidic catalyst, conventional silica-based matting agents can adversely affect the acid and alkali resistance of the coating. Based on the above findings, the inventors of this application, in the formulation of acid-curing coating compositions containing at least one hydroxyl-functional resin, at least one amino compound, and at least one acidic catalyst, obtained solvent-based acid-curing coating compositions with significantly improved acid and alkali resistance by adding specific matting agents (i.e., non-silica-based matting agents). The inventors of this application also surprisingly discovered that, in the formulation of acid-curing coating compositions containing at least one hydroxyl-functional resin, at least one amino compound, and at least one acidic catalyst, by adding such non-silica-based matting agents with specific structures and sizes, the resulting solvent-based acid-curing coating compositions can form coatings with significantly higher whiteness and matte effects. Moreover, this method can also achieve matting of high-solids coating compositions, which was unforeseen before this application.

[0008] Details of one or more embodiments of the present invention are set forth in the following description. Other features, objects, and advantages of the invention will become clear from the description and claims.

[0009] definition

[0010] In this document, unless otherwise stated, the terms "a," "this," "at least one," and "one or more," as well as instances where no quantifier is used, are used interchangeably. Thus, for example, a coating composition containing "a" additive can be interpreted as meaning that the coating composition contains "one or more" additives. Unless otherwise stated herein, the use of the singular form is also intended to include the plural form.

[0011] When a composition is described as including or comprising specific components, it is anticipated that optional components not covered by the present invention are not excluded from the composition, and that the composition may be constituted or composed of the components involved. Similarly, when a method is described as including or comprising specific process steps, it is anticipated that optional process steps not covered by the present invention are not excluded from the method, and that the method may be constituted or composed of the process steps involved.

[0012] In this invention, the numerical range defined by the endpoints includes all values ​​within that range. For example, the range of 1 to 5 encompasses the values ​​1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc. Moreover, the disclosed numerical range includes all subsets of the wider range. For example, the range of 1 to 5 includes subranges 1 to 4, 1.5 to 4.5, 1 to 2, etc.

[0013] For simplicity, this document only explicitly discloses some numerical ranges. However, it should be understood that any range formed by combining any lower limit with any upper limit is included in the scope explicitly disclosed in this invention; similarly, any range formed by combining any lower limit with other lower limits is also included in the scope explicitly disclosed in this invention, and similarly, any range formed by combining any upper limit with other upper limits is also included in the scope explicitly disclosed in this invention. Furthermore, unless otherwise stated, each point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can be used as a lower limit or upper limit combined with any other point or individual value, or combined with other lower limits or upper limits, to obtain a range that is included in the scope explicitly disclosed in this invention.

[0014] When used in relation to "solvent-based acid-curing coating compositions", the term "non-silica-based matting agent" refers to a matting agent that is not based on silica (i.e., silicon dioxide), but may still contain a certain amount (e.g., not more than 30% by weight) of silica that will not adversely affect the properties of the solvent-based acid-curing coating composition formulated therefrom, particularly its acid and alkali resistance.

[0015] In this document, the term "amino resin" refers to the product formed by the polycondensation reaction of an amino compound, i.e. a compound containing at least one primary amine (NH2) functional group and / or an amide (-CO-NH2) functional group, with an aldehyde compound, the product being optionally partially or completely etherified by an aliphatic monohydric alcohol.

[0016] When referring to the use of "hydroxyl-functionalized resins," the term "hydroxyl value" refers to the number of milligrams of potassium hydroxide equivalent to the hydroxyl content per gram of hydroxyl-functionalized resin. The hydroxyl value can be determined using methods known in the art. For example, the hydroxyl value is determined according to standard GB / T 12008.3-2009.

[0017] In the context of this invention, the term "high solids coating composition" refers to a coating composition with a solids content of not less than 65 wt%.

[0018] When referring to coatings formed from solvent-based acid-curing paint compositions, the term "whiteness" is a visually perceived parameter used to measure the surface properties of a coating, describing its ability to reflect light in the visible spectrum (especially the blue region). Typically, coating whiteness is graded from 1 to 5, with 5 being the best and 1 the worst.

[0019] When referring to coatings formed from solvent-based acid-curing paint compositions, the term "gloss" is a visually perceived parameter used to measure the surface performance of a coating. It refers to the ratio or intensity of light reflected from the coating surface under a given illuminance and angle of incident light. The higher the ratio or intensity of light reflected by the coating, the higher its gloss.

[0020] In this article, "coating" and "coating film" have the same meaning, both referring to the coating formed by the application and curing of a solvent-based acid-curing paint composition.

[0021] When used herein, the term "primer" refers to a coating composition that can be applied to a substrate and dried, crosslinked, or otherwise hardened to form a non-sticky, continuous film with adequate adhesion to the substrate surface.

[0022] When used herein, the term "topcoat" refers to a coating composition that can be applied over a primer and dried, crosslinked, or otherwise hardened to form a decorative or protective outermost coating layer. Furthermore, such topcoats are capable of withstanding prolonged outdoor exposure without exhibiting visible, undesirable degradation.

[0023] The terms "preferred" and "ideally" refer to embodiments of the invention that provide certain benefits in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of the invention. Attached Figure Description

[0024] Figure 1 A schematic diagram is shown of the aggregation state of the non-silica-based matting agent during the formation of a coating by the solvent-based acid-curing coating composition of Example 1 of this application, wherein 100 represents an aggregate of multiple non-silica-based matting powders; 101 represents the outer shell of the non-silica-based matting powder particles; and 102 represents the core of the non-silica-based matting powder particles. Detailed Implementation

[0025] This application provides a solvent-based acid-curing coating composition comprising at least one hydroxyl-functional resin, at least one amino resin, at least one acidic catalyst, at least one matting agent, and additional additives, wherein the at least one matting agent comprises at least one non-silica-based matting agent; and wherein the at least one non-silica-based matting agent has a core-shell structure with titanium dioxide as the core and silicon dioxide as the shell, and has a Dv50 particle size of 4-8 micrometers, the particle size being determined by laser diffraction according to ISO 13320-1.

[0026] It is well known that in application scenarios involving complex chemical environments, especially in livestock sheds, the accumulation and decomposition of animal excrement and the application of highly oxidizing disinfectants inevitably lead to the accumulation of various corrosive (acidic and alkaline) chemicals, resulting in a significant reduction in the service life of the sheds. To address this issue, coating formulation technicians typically improve the primer in the coating system used in livestock shed construction materials. For example, in the formulation of coating compositions used as primers, one or more techniques are employed to improve the corrosion resistance, particularly acid and alkali resistance, of coating systems used in livestock sheds. However, this solution has limited effectiveness, and the problem of poor acid and alkali resistance in the coating still exists.

[0027] As the most common matting agents in the coatings industry, silica-based matting agents such as TS100 and Syloid C807 provided by Degussa are widely recognized for their excellent chemical and acid / alkali resistance, making them the most popular matting agents in the formulation of matte coating compositions. However, through extensive experimental research, the inventors of this application have revealed for the first time that in the formulation of solvent-based acid-curing coating compositions, especially in the formulation of acid-curing coating compositions containing at least one hydroxyl-functionalized resin, at least one amino compound, and at least one acidic catalyst, conventional silica-based matting agents, and even silica matting agents such as TS100 and Syloid C807, can adversely affect the acid and alkali resistance of the coating, which was unforeseen before this application.

[0028] Based on the above findings, the inventors of this application obtained a solvent-based acid-curing coating composition with significantly improved acid and alkali resistance by adding a specific matting agent (i.e., a non-silica-based matting agent) to the formulation of an acid-curing coating composition containing at least one hydroxyl-functional resin, at least one amino compound and at least one acid catalyst.

[0029] Therefore, in embodiments of the invention, the solvent-based acid-curing coating composition contains at least one non-silica-based matting agent as a matting agent. As described above, "non-silica-based matting agent" refers to a matting agent that is not based on silica (i.e., silicon dioxide), but may still contain a certain amount (e.g., not exceeding 30% by weight) of silica that will not adversely affect the performance, particularly the acid and alkali resistance, of the solvent-based acid-curing coating composition formulated therefrom. In some embodiments of the invention, the non-silica-based matting agent is a matting agent with titanium dioxide as the main component and containing a certain amount of silica, wherein the titanium dioxide is present in an amount of 70% by weight or higher relative to the total weight of the non-silica-based matting agent, preferably in an amount of 71% by weight or higher relative to the total weight of the non-silica-based matting agent, more preferably in an amount of 72% by weight or higher relative to the total weight of the non-silica-based matting agent, and even more preferably in an amount of 73% by weight or higher relative to the total weight of the non-silica-based matting agent. Accordingly, in this embodiment of the invention, silica is present in an amount of 30% by weight or less relative to the total weight of the non-silica-based matting agent, preferably in an amount of 29% by weight or less relative to the total weight of the non-silica-based matting agent, more preferably in an amount of 28% by weight or less relative to the total weight of the non-silica-based matting agent, and even more preferably in an amount of 27% by weight or less relative to the total weight of the non-silica-based matting agent. The non-silica-based matting agent having the above-mentioned components, when involved in the formulation of solvent-based acid-curing coating compositions, particularly in the formulation of acid-curing coating compositions comprising at least one hydroxyl-functional resin, at least one amino compound, and at least one acidic catalyst, does not adversely affect the acid and alkali resistance of the coating formed by the resulting coating composition.

[0030] Moreover, the inventors of this application have surprisingly discovered that, in the formulation of an acid-curing coating composition containing at least one hydroxyl-functional resin, at least one amino compound, and at least one acidic catalyst, by adding this non-silica-based matting powder with a specific structure and size, the resulting solvent-based acid-curing coating composition forms a coating that simultaneously has significantly higher whiteness and excellent matte effect. Furthermore, this method can also achieve matte finish on high-solids coating compositions, which was unforeseen before this application.

[0031] Therefore, in an embodiment of the invention, the at least one non-silica-based matting powder has a core-shell structure with titanium dioxide as the core and silicon dioxide as the shell, and has a Dv50 particle size of 4-8 micrometers, which is determined by laser diffraction according to ISO 13320-1.

[0032] As described above, in the solvent-based acid-curing coating composition according to the present invention, the non-silica-based matting powder has a core-shell structure with titanium dioxide as the core and silica as the shell. By using a non-silica-based matting powder with this specific structure, the amount of conventional silica can be significantly reduced, thereby improving the acid and alkali resistance of the coating. Moreover, in embodiments according to the present invention, the non-silica-based matting powder has a core-shell structure with titanium dioxide as the core and silica as the shell. During the coating formation process from the solvent-based acid-curing coating composition, the non-silica-based matting powder with this structure aggregates in a grape-like pattern, such as... Figure 1 As shown. The inventors of this application have surprisingly discovered that the whiteness and gloss of the coating are related to the aggregation mode of the white matting powder incorporated into the solvent-based acid-curing coating used to form the coating. Therefore, in the formulation of the solvent-based acid-curing coating composition according to the present invention, incorporating a non-silica-based matting powder having such a core-shell structure can significantly improve the whiteness of the coating formed by the resulting solvent-based acid-curing coating composition, and can ensure that the resulting coating has a suitable matte effect.

[0033] In some embodiments of the present invention, after the solvent-based acid-curing coating composition is applied to a substrate and cured, the resulting coating has a whiteness of 4.5 or higher, the whiteness being measured using a colorimeter. Thus, the coating formed by the obtained solvent-based acid-curing coating composition has significantly higher whiteness.

[0034] In some embodiments of the present invention, after the solvent-based acid-curing coating composition is applied to a substrate and cured, the resulting coating has a gloss level of 60° not exceeding 45, the gloss level being determined by GB / T 1743-1989. Thus, the coating formed by the obtained solvent-based acid-curing coating composition has a matte finish.

[0035] Furthermore, the inventors of this application were even more surprised to discover that precisely because non-silica-based matting powders with this core-shell structure exhibit a grape-bundle-like aggregate structure during the coating formation process of the solvent-based acid-cured coating composition, the matting powder according to the present invention can still achieve matting of high-solids coating compositions even with a significantly smaller particle size (e.g., 4-8 micrometers Dv50), which is contrary to conventional knowledge in the art. It is well known that for matting high-solids coatings, coarse silica is required, and in relatively high quantities. For matting high-solids coatings, an average particle size of up to 11 micrometers, a highly porous solvent (1.8-2.0 mL / g), and micron-sized synthetic silica aerogels are commercially available. In embodiments according to the present invention, the at least one non-silica-based matting powder has a Dv50 particle size of 4-8 micrometers, preferably 4-6 micrometers, which is determined by laser diffraction according to ISO 13320-1. This particle size of matting agent can achieve good matting when used to formulate solvent-based acid-curing coating compositions with a solid content of up to 65% or higher.

[0036] Therefore, in a preferred embodiment of the invention, the at least one non-silica-based matting powder exhibits a grape-like aggregate structure in the coating formed by the solvent-based acid-curing coating composition.

[0037] The solvent-based acid-curing coating composition according to embodiments of this application comprises a non-silica-based matting agent as the main component of the matting agent. Therefore, in one embodiment of the invention, the at least one non-silica-based matting agent is present in an amount of 10-25 wt% relative to the total weight of the solvent-based acid-curing coating composition. The non-silica-based matting agent can be any suitable non-silica-based matting agent known to those skilled in the art, such as PFR410 commercially available from Ishihara Sangyo Co., Ltd.

[0038] In addition to non-silica-based matting agents, the solvent-based acid-curing coating compositions according to embodiments of the present invention may also contain a certain amount of at least one silica-based matting agent, provided that such an amount of silica-based matting agent does not adversely affect the performance, particularly the acid and alkali resistance, of the solvent-based acid-curing coating composition formulated therefrom. Therefore, in one embodiment of the present invention, the at least one silica-based matting agent is present in an amount not exceeding 3 wt% of the total weight of the solvent-based acid-curing coating composition, preferably not exceeding 1 wt%. The non-silica-based matting agent can be any suitable silica-based matting agent well known to those skilled in the art, such as matting agent with the brand name Syloid C807.

[0039] In embodiments of the present invention, the solvent-based acid-curing coating composition, in addition to the aforementioned matting agent, also comprises a film-forming resin. Hereinafter, the film-forming resin refers to a resin composition constituting the main body of the coating formed by the acid-curing coating composition, which comprises hydroxyl-functionalized resins and amino resins. In embodiments of the present invention, the hydroxyl-functionalized resins and amino resins, as resin components or part of resin components, constitute the main body of the coating formed by the solvent-based acid-curing coating composition of the present invention, thereby providing sufficient mechanical strength to the formed coating.

[0040] In some embodiments according to this application, the hydroxyl-functional resin may, for example, include at least one hydroxyl-functional epoxy, at least one hydroxyl-functional polyurethane, at least one hydroxyl-functional polyester, at least one hydroxyl-functional polyether, at least one hydroxyl-functional alkyd resin, at least one hydroxyl-functional acrylic resin, or combinations thereof. In the presently preferred embodiments, the hydroxyl-functional resin may include at least one hydroxyl-functional polyester.

[0041] In some embodiments of the present invention, the hydroxyl-functionalized polyester resin comprises at least one first hydroxyl-functionalized polyester resin having a hydroxyl value in the range of 50-70 mg KOH / g, said hydroxyl value being determined according to GB12009.3-2009, and is therefore also referred to as a medium hydroxyl-value polyester resin. Preferably, the hydroxyl value of the first hydroxyl-functionalized polyester resin can be at least 50 mg KOH / g, such as at least 55 mg KOH / g, such as at least 60 mg KOH / g, and the hydroxyl value of the first hydroxyl-functionalized polyester resin can be at most 70 mg KOH / g, such as at most 68 mg KOH / g, such as at most 65 mg KOH / g. In one embodiment, the hydroxyl value of the first hydroxyl-functionalized polyester resin is in the range of 50-70 mg KOH / g, 55-70 mg KOH / g, 60-70 mg KOH / g, 65-70 mg KOH / g, 50-68 mg KOH / g, 55-68 mg KOH / g, 60-68 mg KOH / g, 65-68 mg KOH / g, 60-70 mg KOH / g, 60-68 mg KOH / g, 65-65 mg KOH / g, with the most preferred value being 65 mg KOH / g.

[0042] In some embodiments of the present invention, the hydroxyl-functionalized polyester resin comprises at least one second hydroxyl-functionalized polyester resin having a hydroxyl value in the range of 90-100 mg KOH / g, said hydroxyl value being determined according to GB12009.3-2009, and is therefore also referred to as a high hydroxyl-value polyester resin. Preferably, the hydroxyl value of the second hydroxyl-functionalized polyester resin can be at least 90 mg KOH / g, such as at least 91 mg KOH / g, such as at least 92 mg KOH / g, and the hydroxyl value of the second hydroxyl-functionalized polyester resin can be at most 100 mg KOH / g, such as at most 99 mg KOH / g, such as at most 98 mg KOH / g. In one embodiment, the hydroxyl value of the second hydroxyl-functionalized polyester resin is in the range of 90-100 mg KOH / g, 91-100 mg KOH / g, 92-100 mg KOH / g, 90-99 mg KOH / g, 91-99 mg KOH / g, 92-99 mg KOH / g, 90-98 mg KOH / g, 91-98 mg KOH / g, and 92-98 mg KOH / g.

[0043] The above-mentioned medium-hydroxyl-value polyester resin and high-hydroxyl-value polyester resin can be compounded to improve the crosslinking density of the paint film while ensuring that the paint film has a certain degree of flexibility.

[0044] The molecular weights of the first and second hydroxyl-functionalized polyester resins described above can vary depending on the material selection and the desired end application. Optionally, the first and second hydroxyl-functionalized polyester resins can have any suitable number-average molecular weight (Mn), which is determined according to ASTM D6579-11. For example, the Mn of the first and second hydroxyl-functionalized polyester resins can be at least 3000 Daltons (Da = g / mol), such as at least 3,500 Da. The Mn of the first and second hydroxyl-functionalized polyester resins can be up to 20,000 Da, such as up to 18,000 Da, such as up to 15,000 Da, such as up to 13,000 Da, or even up to 12,000 Da. The Mn of the first and second hydroxyl-functionalized polyester resins can be from 3000 Da to 20,000 Da, or from 3000 Da to 18,000 Da, or from 3000 Da to 15,000 Da, or from 3000 Da to 13,000 Da, or from 3000 Da to 12,000 Da, or from 3000 Da to 10,000 Da, or from 3000 Da to 9,000 Da, or from 3000 Da to 8,000 Da, or from 3000 Da to 7,000 Da, or from 3000 Da to 6,000 Da, or from 3000 Da to 5,000 Da, or from 3000 Da to 4,000 Da. In some preferred embodiments of the invention, the first hydroxyl-functionalized polyester resin and the second hydroxyl-functionalized polyester resin each independently have a number-average molecular weight in the range of 3000-5000 g / mol. In this paper, Mn was determined using the polystyrene standard by gel permeation chromatography according to ASTM D6579-11. All Mn values ​​reported herein were measured in this manner. If the molecular weight of the first and second hydroxyl-functionalized polyester resins is too high, the coating compositions formulated therefrom are difficult to apply evenly and are unsuitable for application; if the molecular weight of the first and second hydroxyl-functionalized polyester resins is too low, the coating compositions formulated therefrom form a film with limited strength after curing. Therefore, in some embodiments according to this application, the molecular weights of the first and second hydroxyl-functionalized polyester resins are appropriate within the aforementioned ranges.

[0045] In some embodiments according to this application, the first hydroxyl-functionalized polyester resin has a significant impact on the acid and alkali resistance of the coating, and is present in an amount of at least 15% by weight relative to the total weight of the solvent-based acid-curing coating composition. For example, the first hydroxyl-functionalized polyester resin may be present in an amount of at least 15% by weight, at least 20% by weight, and at most 50% by weight, at most 45% by weight, and at most 40% by weight relative to the total weight of the solvent-based coating composition. In a preferred embodiment according to this application, the amount of the first hydroxyl-functionalized polyester resin, relative to the total weight of the solvent-based coating composition, is in the range of 25 to 45% by weight, preferably in the range of 25 to 40% by weight, and more preferably in the range of 25 to 35% by weight. If the amount of the first hydroxyl-functionalized polyester resin is too low, the acid and alkali resistance of the coating cannot be achieved; if the amount of the first hydroxyl-functionalized polyester resin is too high, the strength of the coating will be insufficient, and the surface of the resulting product will be easily damaged during subsequent processing, failing to meet application requirements. Therefore, in some embodiments according to this application, the amount of the first hydroxyl-functionalized polyester resin is appropriate within the above-mentioned range, which makes the coating composition formulated therefrom have excellent acid and alkali resistance and mechanical properties.

[0046] In some embodiments of this application, the second hydroxyl-functionalized polyester resin can be present in the solvent-based acid-curing coating composition in any suitable amount as needed. In one embodiment of this application, the amount of the second hydroxyl-functionalized polyester resin, relative to the total weight of the solvent-based acid-curing coating composition, is no more than 20 wt%, preferably in the range of 5 to 20 wt%, and more preferably in the range of 5 to 15 wt%. If the amount of the second hydroxyl-functionalized polyester resin is too high, it will adversely affect the flexibility of the coating, and the resulting article is prone to cracking during subsequent necking treatment, failing to meet application requirements. Therefore, in some embodiments of this application, the amount of the second hydroxyl-functionalized polyester resin within the above-mentioned range is appropriate, which makes the coating composition formulated therefrom have excellent mechanical properties.

[0047] Furthermore, to ensure the coating performance of the solvent-based coating composition according to the present invention, the ratio of the first hydroxyl-functionalized polyester resin to the second hydroxyl-functionalized polyester resin is also a factor that needs to be considered. The inventors of this application have discovered that controlling the mass ratio of the first hydroxyl-functionalized polyester resin to the second hydroxyl-functionalized polyester resin within a certain range is beneficial for the application of the obtained coating composition in high-speed coating production lines for packaging products, resulting in a coating that not only has excellent acid and alkali resistance but also exhibits favorable flexural strength. In some embodiments according to the present invention, the mass ratio of the first hydroxyl-functionalized polyester resin to the second hydroxyl-functionalized polyester resin is in the range of 1.5 to 3:1, preferably in the range of 1.5 to 2:1, and more preferably in the range of 1.5 to 1.8:1.

[0048] As described above, in a preferred embodiment of the invention, a hydroxyl-functionalized polyester resin is used as the hydroxyl-functionalized resin. The term "polyester resin" herein refers to a liquid alkyd resin prepared by condensation polymerization of a polyol, a polyacid, or anhydride together. Representative polyols include glycerol, pentaerythritol, sorbitol, trimethylolpropane, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and other polyols known to those skilled in the art as being suitable for preparing polyester resins. Representative polyacids or anhydrides include diacids or anhydrides such as phthalic acid and its anhydrides, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, etc.; tricarboxylic acids such as trimellitic acid; and other polyacids or anhydrides known to those skilled in the art as being suitable for preparing polyester resins. Polyester resins can be prepared using appropriate preparation methods known to those skilled in the art, or can be obtained from any suitable commercially available product, such as ESC-2233B from Dongsheng, or Dynapol EP 112N from Evonik.

[0049] In one embodiment of this application, the amount of hydroxyl-functionalized resin can vary over a wide range. For example, relative to the total weight of the solvent-based acid-curing coating composition, the amount of hydroxyl-functionalized resin can be no more than 69 wt%, no more than 65 wt%, and at least 20 wt%, at least 25 wt%. In a preferred embodiment of this application, the amount of hydroxyl-functionalized resin, relative to the total weight of the solvent-based acid-curing coating composition, is in the range of 25 to 65 wt%. Generally, the desired amount of hydroxyl-functionalized resin can be empirically selected based on the film-forming properties of the coating film.

[0050] In some embodiments of this application, the solvent-based acid-curing coating composition contains, in addition to the hydroxyl-functionalized resin described above, an amino resin as a film-forming resin.

[0051] As mentioned above, amino resins refer to the condensation products of aldehydes (such as formaldehyde, acetaldehyde, crotonaldehyde, and benzaldehyde) and amino compounds containing amino or amide groups (such as urea, melamine, benzomelamine, or methylmelamine). Other condensation products of amines and amides, such as triazine, diazine, triazole, guanidine, guanidineamine, and aldehyde condensates of alkyl-substituted and aryl-substituted melamines, can also be used. Some examples of such compounds are N,N'-dimethylurea, benzourea, dicyandiamide, methylguanidine, ethylguanidine, glycourea, cyanuric acid diamide, 2-chloro-4,6-diamino-1,3,5-triazine, 6-methyl-2,4-diamino-1,3,5-triazine, 3,5-diaminotriazole, triaminopyrimidine, 2-mercapto-4,6-diaminopyrimidine, 3,4,6-tris(ethylamino)-1,3,5-triazine, etc. Although formaldehyde is typically used, other aldehydes such as acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, glyoxal, and mixtures thereof can also be used. In the presently preferred embodiment of the invention, melamine-formaldehyde, benzomelamine-formaldehyde, glycyrrhizin-formaldehyde, methylmelamine-formaldehyde, or combinations thereof are used as the amino resin.

[0052] In some preferred embodiments of the invention, the amino resin may optionally be partially alkylated. In some embodiments, the amino resin is a n-butanol-etherified amino resin, an isobutyl-etherified amino resin, a methanol-etherified amino resin, or any combination thereof. Particularly preferred, the amino resin according to some embodiments of the invention comprises an incompletely etherified amino resin.

[0053] Amino resins are commercially available, and non-limiting examples of suitable commercially available amino resins include Cymel 303LF, Cymel 1123, Cymel 1170, etc. from Cytec.

[0054] The amount of amino resin may depend on various factors, including, for example, the type of amino resin, baking time and temperature, the molecular weight of the hydroxyl-functionalized resin, and the desired coating properties. Based on the total weight of the film-forming composition, the amino resin is typically present in an amount of up to 30 wt%, preferably up to 25 wt%, more preferably up to 20 wt%, and in an amount of at least 2 wt%, at least 3 wt%, and at least 5 wt%. In a preferred embodiment according to this application, the amount of amino resin, relative to the total weight of the solvent-based acid-curing coating composition, is in the range of 2 to 30 wt%, preferably in the range of 5 to 30 wt%, more preferably in the range of 5 to 20 wt%. Generally, the desired amount of amino resin can be empirically selected based on the film-forming properties of the coating. Furthermore, in embodiments according to the invention, the acid-curing coating composition may also contain at least one acidic catalyst. Examples of acidic catalysts include, but are not limited to, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, dodecylbenzenesulfonic acid, oxalic acid, maleic acid, phthalic acid, acrylic acid, mono(di)alkyl phosphate, phosphoric acid, mono(di)alkyl pyrophosphate, or combinations thereof.

[0055] In the solvent-based acid-curing coating compositions according to this application, the amount of acidic catalyst can be adjusted as needed, particularly based on the amount of hydroxyl-functionalized resin and / or amino resin, according to the experience of those skilled in the art. In some embodiments of this application, the acidic catalyst is present in amounts of up to 15 wt%, up to 10 wt%, up to 8 wt%, up to 5 wt%, and up to 2 wt%, and at least 0.01 wt%, at least 0.05 wt%, and at least 0.1 wt%. In some preferred embodiments of the invention, the amount of acidic catalyst is in the range of 0.1-10 wt%, preferably in the range of 0.1-5 wt%, and more preferably in the range of 0.1-1 wt%. These weight percentages are determined based on the total weight of the solvent-based acid-curing coating composition.

[0056] In embodiments of this application, and in some embodiments thereof, the solvent-based acid-curing coating composition may contain an organic solvent to further adjust the viscosity of the coating composition. The addition of an organic solvent can increase the evaporation rate of the coating composition and accelerate film formation. In some embodiments of this application, the organic solvent includes ketones (e.g., acetone, methyl isopropyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), aromatic hydrocarbons (toluene, xylene, etc.), aliphatic hydrocarbons (cyclopentane, cyclohexane, etc.), or any combination thereof.

[0057] In a preferred embodiment of the present application, if present, the solvent may comprise, for example, at least 0.1 wt%, at least 1 wt%, at least 3 wt%, at least about 5 wt%, at least about 6 wt%, at least about 7 wt%, at least about 8 wt%, at least about 9 wt%, or at least about 10 wt% of the total weight of the solvent-based acid-curing coating composition. In a preferred embodiment of the present application, if present, the solvent may comprise, for example, at most 30 wt%, at most 25 wt%, at most about 20 wt%, at most about 19 wt%, at most about 18 wt%, or at most about 17 wt% of the total weight of the solvent-based acid-curing coating composition. Generally, the desired amount of solvent is empirically selected based on the film-forming properties of the coating.

[0058] In some embodiments of the invention, the solvent-based acid-curing coating composition may further comprise optional additional additives, which may be those commonly used in coating compositions. These additives do not adversely affect the coating composition or the cured coating obtained therefrom. Suitable additives include, for example, those agents that improve the processability or manufacturing properties of the composition, enhance the aesthetics of the composition, or improve specific functional properties or characteristics (such as adhesion to a substrate) of the coating composition or the cured composition obtained therefrom. Additives that may be included in the film-forming composition, depending on specific needs, include, but are not limited to, anti-skinning agents, driers, film-forming aids, coupling agents, pigments, fillers, anti-settling agents, anti-migration aids, antibacterial agents, antifungal agents, lubricants, wetting agents, biocides, plasticizers, defoamers, colorants, waxes, antioxidants, corrosion inhibitors, rheology modifiers, dispersants, adhesion promoters, UV stabilizers, leveling agents, or combinations thereof. The amounts of each optional component are sufficient to achieve their intended purpose, but preferably, such amounts do not adversely affect the coating composition or the cured coating obtained therefrom. Preferably, the additional additives include pigments, fillers, thickeners, antisettling agents, dispersants, wetting agents, film-forming aids, coupling agents, bactericides, fungicides, or any combination thereof.

[0059] In some embodiments of the invention, the total amount of the additional additives is in the range of about 0 wt% to about 30 wt% relative to the total weight of the solvent-based acid-curing coating composition, preferably in the range of about 0.1 wt% to about 30 wt%.

[0060] In one specific embodiment of this application, the film-forming composition of the solvent-based acid-curing coating composition comprises, relative to the total weight of the solvent-based acid-curing coating composition,

[0061] 25-65 wt% of the at least one hydroxyl-functionalized resin;

[0062] 5-15 wt% of the at least one amino resin;

[0063] 10-30 wt% of the at least one matting agent;

[0064] 0.1-1 wt% of the at least one acidic catalyst;

[0065] At least one solvent, 0.1-25 wt%; and

[0066] 0-30 wt% of additional additives, said additional additives including at least one pigment, at least one filler, at least one thickener, at least one dispersant, at least one wetting agent, at least one film-forming aid, at least one coupling agent, at least one bactericide, at least one fungicide, or any combination thereof.

[0067] The solvent-based acid-curing coating composition of this application can be prepared by any suitable mixing method known to those skilled in the art. For example, the coating composition can be prepared by adding a hydroxyl-functionalized resin, an amino resin, a matting agent, an acid catalyst, a solvent, and additional additives (if any) to a container, and then stirring the resulting mixture until homogeneous, thereby forming a solvent-based acid-curing coating composition.

[0068] In some embodiments of the invention, the solvent-based acid-curing coating composition thus formed has a solid content of 65% or higher.

[0069] In some embodiments of the invention, the solvent-based acid-curing coating composition thus formed, after being applied to a substrate and cured, results in a coating with a whiteness of 4.5 or higher, the whiteness being measured using a colorimeter.

[0070] In some embodiments of the invention, the solvent-based acid-curing coating composition thus formed, after being applied to a substrate and cured, forms a coating with a gloss of 60° not exceeding 45, said gloss being determined by GB / T1743-1989.

[0071] In a preferred embodiment of the invention, the solvent-based acid-curing coating composition thus formed, after being applied to a substrate and cured, produces a coating with excellent acid and alkali resistance, which is determined by the cup method according to GB / T1766-2008.

[0072] Therefore, the solvent-based acid-curing coating composition according to embodiments of the present invention is suitable for applications with complex chemical environments and has extremely high promotional value in industries such as animal husbandry, planting, medical care, hygiene, chemical industry, and papermaking.

[0073] According to a second aspect of the invention, an article is provided comprising: a substrate having at least one main surface; a base coating applied directly or indirectly to at least a portion of the main surface of the substrate; and a top coating applied directly or indirectly to at least a portion of the main surface of the substrate, wherein the top coating is formed from the solvent-based acid-curing coating composition described above.

[0074] As the substrate for manufacturing the articles of this application, any suitable metal substrate known in the art can be used. As an example, the metal substrate is selected from one or more of steel, iron, aluminum, zinc, copper, and alloys.

[0075] As a primer coating for manufacturing the articles of this application, any suitable primer coating known in the art can be used. As an example, the primer coating can be formed from a primer coating composition comprising a film-forming resin, a crosslinking agent, and an adhesion promoter.

[0076] In a presently preferred embodiment, the primer composition may comprise one or more of epoxy resin, polyester resin, and acrylic resin as a film-forming resin. In a presently more preferred embodiment, the film-forming resin may be selected from epoxy resin.

[0077] In a preferred embodiment according to this application, the resin component is an epoxy resin. The term "epoxy resin" refers to a polymer or oligomer containing two or more epoxy groups per molecule. Preferably, each molecule of an epoxy resin may contain up to four epoxy groups. Preferably, each molecule of an epoxy resin may contain two or three epoxy groups. According to certain embodiments of this application, the epoxy resin may have an epoxy equivalent that varies over a wide range, where epoxy equivalent refers to the mass of epoxy resin containing 1 mol of epoxy groups. Hereinafter, high epoxy equivalent epoxy resins with an epoxy equivalent between 1800-2200 g / eq may be used.

[0078] Suitable epoxy resins include, for example, diglycidyl ethers of polyphenols, such as diglycidyl ethers of resorcinol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, and tetramethylbisphenol; diglycidyl ethers of polyols, such as diglycidyl ethers of aliphatic glycols and polyether glycols, for example, C... 2-24Diglycidyl ethers of alkylene glycols, diglycidyl ethers of poly(ethylene oxide) glycols, or diglycidyl ethers of poly(propylene oxide) glycols; polyglycidyl ethers of phenolic resins, such as polyglycidyl ethers of phenol-formaldehyde resins, polyglycidyl ethers of alkyl-substituted phenol-formaldehyde resins, polyglycidyl ethers of phenol-hydroxybenzaldehyde resins, or polyglycidyl ethers of cresol-hydroxybenzaldehyde resins; or combinations thereof.

[0079] According to certain embodiments of this application, the epoxy resin is a diglycidyl ether of a polyphenol, and is particularly preferably having the following structural formula (I):

[0080]

[0081] Wherein, D represents -S-, -SS-, -SO-, -SO2-, -CO2-, -CO-, -O- or a divalent alkyl group having 1 to 10, preferably 1 to 5, more preferably 1 to 3 carbon atoms, such as -CH2- or -C(CH3)2-;

[0082] Each Y is independently a halogen, such as F, Cl, Br, or I, or optionally a monovalent C1-C that is substituted. 10 Hydrocarbon groups, such as optionally substituted methyl, ethyl, vinyl, propyl, allyl, or butyl groups;

[0083] Each m is independently 0, 1, 2, 3, or 4; and

[0084] n is an integer from 0 to 4, such as 0, 1, 2, 3, or 4.

[0085] More preferably, the epoxy resin is a bisphenol A type epoxy resin, a bisphenol S type epoxy resin or a bisphenol F type epoxy resin having the structural formula (I), wherein D represents -C(CH3)2-, -SO2- or -CH2- respectively, m represents 0, and n is an integer from 0 to 4.

[0086] Most preferably, the epoxy resin is a bisphenol A type epoxy resin having structural formula (I), wherein D represents -C(CH3)2-, m represents 0, and n is an integer from 0 to 4.

[0087] The epoxy resins disclosed above can be manufactured, for example, using epichlorohydrin technology well known to those skilled in the art. As examples of epoxy resins, any conventional epoxy resin can be used, such as E12, E14, E06, and E20, available from Shanghai Kaiping Resin Co., Ltd.

[0088] In some embodiments of the invention, the total amount of epoxy resin is in the range of about 50 wt% to about 70 wt% relative to the total weight of the primer coating composition, preferably in the range of about 55 wt% to about 70 wt%.

[0089] In the present preferred embodiment, the primer coating composition may contain one or more of amino resins and polyisocyanates as crosslinking agents, wherein the amino resin may be an amino resin commonly used in the art to formulate coating compositions, as described above, and the polyisocyanate may be a polyisocyanate commonly used in the art to formulate coating compositions. As an example, suitable isocyanate crosslinking agents are aliphatic, alicyclic, and aromatic polyisocyanates, such as trimethylene diisocyanate, 1,2-propylidene diisocyanate, tetramethylene diisocyanate, 2,3-butylidene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecamethyl diisocyanate, 1,3-cyclopentylene diisocyanate, 1,2-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4-methyl-1,3-cyclohexylene diisocyanate, m- and p-phenylene diisocyanate, 1 3- and 1,4-bis(isocyanate methyl)benzene, 1,5-dimethyl-2,4-bis(isocyanate methyl)benzene, 1,3,5-triisocyanate benzene, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,4,6-toluene triisocyanate, α,α,α′,α′-tetramethylo-, m- and p-xylene diisocyanate, 4,4′-diphenylene diisocyanate methane, 4,4′-diphenylene diisocyanate, 3,3′-dichloro-4,4′-diphenylene diisocyanate, naphthalene-1,5-diisocyanate, isophorone diisocyanate, trans-ethylenediisocyanate, and mixtures thereof. Adducts of the above polyisocyanates are also suitable, such as biuret, isocyanurate, allophonate, uretdione, and mixtures thereof. Depending on the application, the above-mentioned isocyanates and their adducts may exist in the form of capped or potential isocyanates.

[0090] In some embodiments of the invention, the total amount of amino resin is in the range of about 5 wt% to about 7 wt% relative to the total weight of the primer composition; the total amount of polyisocyanate is in the range of about 1 wt% to about 3 wt% relative to the total weight of the primer composition.

[0091] In a currently preferred embodiment, the primer coating composition may further contain an adhesion promoter. As an example, the adhesion promoter may be selected from one or more of phosphoric acid and epoxy phosphate. In some embodiments of the invention, the total amount of adhesion promoter relative to the total weight of the primer coating composition is in the range of about 0.1 wt% to about 5 wt%, preferably in the range of 0.1 wt% to about 4 wt%.

[0092] According to this application, the article can be prepared, for example, by the following steps: (1) providing a polished metal substrate; (2) applying and forming a base coating and a top coating on the metal substrate in sequence using a coating and curing process to provide corrosion protection for the metal substrate.

[0093] According to this application, the resulting metal articles can be used in the following end applications, including, but not limited to: refrigerated and non-refrigerated transport containers (e.g., dry cargo containers) derived from suppliers or manufacturers including China International Marine Containers (CIMC), Graaff Transportsysteme GmbH, Maersk Line, and other suppliers or manufacturers well known to those skilled in the art; chassis, trailers (including semi-trailers), rail vehicles, truck bodies, ships, bridges, building frames, and prefabricated or on-site metal components requiring temporary indoor or outdoor corrosion protection during manufacturing. Additional uses include metal corners, passageways, beams (e.g., I-beams), pipes, tubes, plates, or other components that can be welded into these or other metal components.

[0094] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations within the scope of the disclosure of this application will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available and ready for use without further processing.

[0095] Example

[0096] The disclosure of this invention is described in more detail through the examples below. These examples are merely illustrative and are not limited to these specific examples. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available and ready for use without further processing.

[0097] Test methods

[0098] Unless otherwise stated, the following test methods are used in this document.

[0099] Hydroxyl value

[0100] This test is used to measure the activity of hydroxyl-functionalized resins. The hydroxyl value of hydroxyl-functionalized resins is determined according to GB12009.3-2009.

[0101] Acid and alkali resistance

[0102] After mixing the components of the solvent-based acid-curing coating composition according to this application, the resulting mixture is applied to a support test plate at room temperature with a wet film thickness of 100-150 micrometers and cured at room temperature for 24 hours to form the test sample.

[0103] According to GB / T 1766-2008, the acid and alkali resistance of the test sample is determined using the cup method. Specifically, the test plate is sealed to one end of a glass tube with glue and left for 5 hours. Then, reagent (e.g., 10% hydrochloric acid aqueous solution or sodium hydroxide aqueous solution) is added to approximately half the volume of the glass tube, and the other end is sealed with a plate. The duration of no change on the paint film surface is then recorded.

[0104] Whiteness

[0105] This test is used to measure the whiteness of the cured coating. The components of the solvent-based acid-curing coating composition according to this application are mixed, and the resulting mixture is applied to a support test plate at room temperature with a wet film thickness of 100-150 micrometers, and cured at room temperature for 24 hours. Then, the L value of the coating is tested using a colorimeter to determine the whiteness, where the whiteness of the coating can be divided into 1-5 grades, with grade 5 being the best and grade 1 being the worst.

[0106] gloss

[0107] This test is used to measure the gloss of the cured coating. The components of the solvent-based acid-curing coating composition according to this application are mixed, and the resulting mixture is applied to a support test plate at room temperature with a wet film thickness of 100-150 micrometers, and cured at room temperature for 24 hours. Then, the 60° gloss is evaluated according to GB / T1743-1989.

[0108] Raw materials:

[0109] Primer coating:

[0110] Epoxy resin: 1001-42 purchased from Yatu, with an epoxy equivalent between 1800 and 2200;

[0111] Amino resin: 5265 purchased from Jiangsu Sanmu Group Co., Ltd.

[0112] HDI: BL3175CN purchased commercially from Covestro

[0113] Adhesion promoter A: Phosphoric acid, commercially available

[0114] Adhesion promoter B: Epoxy phosphate, commercially available

[0115] Topcoat:

[0116] Medium-hydroxyl polyester resin: ESC-2233B purchased from Dongsheng, with a hydroxyl value between 50-70 mgKOH / g;

[0117] High hydroxyl polyester resin: DYNAPOL EP 112N, commercially available from Evonik, with a hydroxyl value between 90-100 mg KOH / g;

[0118] Amino resin: Amino resin with the brand name CYMEL 303LF;

[0119] Acidic catalyst: brand name is 6051 catalyst;

[0120] Non-silica-based matting agent: matting agent with the grade PFR410, with a particle size of 4-6 micrometers, is a core-shell structure matting agent with titanium dioxide as the core and silica as the shell, and the titanium dioxide content is 73%.

[0121] Other non-silica matting agents: brand name is M5 is a urea-formaldehyde condensate, a non-core-shell matting powder with a particle size of 3.5-6.0 micrometers;

[0122] Silica-based matting agent: Silica matting agent with the grade SYLOID C807;

[0123] Silica-based matting agent: Silica matting agent with grade T100;

[0124] Filler: Titanium dioxide of grade TIPURE R-960;

[0125] Solvent: General industrial products;

[0126] Comparison topcoat: Sherwin-Williams High Gloss Topcoat SWNA2106-705 / A

[0127]

[0128]

[0129] As shown in Table 1, in the formulation of acid-curing coating compositions containing hydroxyl-functional resins, amino compounds, and acidic catalysts, the addition of non-silica-based matting agents resulted in coatings with excellent acid and alkali corrosion resistance. Furthermore, due to the specific structure and dimensions of the non-silica-based matting agents, such as… Figure 1As shown, during the coating formation process of the solvent-based acid-curing coating composition, this non-silica-based matting powder aggregates in a grape-like pattern, where 100 represents an aggregate of multiple non-silica-based matting powder particles; 101 represents the outer shell of the non-silica-based matting powder particles; and 102 represents the core of the non-silica-based matting powder particles. It is precisely because of this specific aggregate structure that the coating formed by the solvent-based acid-curing coating composition according to the present invention exhibits significantly higher whiteness and a matte finish, and can also achieve matting for high-solids coating compositions.

[0130] Although this application has been described with reference to numerous embodiments and examples, those skilled in the art will recognize from the disclosure of this application that other embodiments can be designed without departing from the protection scope of this application.

Claims

1. A solvent-based acid-curing coating composition, comprising: The mixture comprises at least one hydroxyl-functionalized resin, at least one amino resin, at least one acidic catalyst, at least one matting agent, and additional additives. in, The at least one matting agent comprises at least one non-silica-based matting agent; and The at least one non-silica-based matting powder has a core-shell structure with titanium dioxide as the core and silicon dioxide as the shell, and has a Dv50 particle size of 4-8 micrometers, which is determined by laser diffraction according to ISO 13320-1.

2. The solvent-based acid-curing coating composition according to claim 1, wherein, The at least one non-silica-based matting agent has a Dv50 particle size of 4-6 micrometers, which is determined by laser diffraction according to ISO 13320-1.

3. The solvent-based acid-curing coating composition according to claim 1, wherein, The at least one non-silica-based matting agent has a titanium dioxide or barium sulfate content of 70% or more relative to the total weight of the at least one non-silica-based matting agent.

4. The solvent-based acid-curing coating composition according to claim 1, wherein, The at least one non-silica-based matting agent exhibits a grape-bundle-like aggregate structure in the coating formed by the solvent-based acid-curing coating composition.

5. The solvent-based acid-curing coating composition according to claim 1, wherein, The at least one non-silica-based matting agent is present in an amount of 10-25 wt% relative to the total weight of the solvent-based acid-curing coating composition.

6. The solvent-based acid-curing coating composition according to any one of claims 1 to 5, wherein, The at least one matting agent further comprises at least one silica-based matting agent, wherein the at least one silica-based matting agent is present in an amount not exceeding 3 wt% of the total weight of the solvent-based acid-curing coating composition, preferably not exceeding 1 wt%.

7. The solvent-based acid-curing coating composition according to any one of claims 1 to 5, wherein, The at least one hydroxyl-functionalized resin comprises at least one medium-hydroxyl polyester resin with a hydroxyl value in the range of 50 to 70 mg KOH / g, the hydroxyl value being determined according to GB12009.3-2009.

8. The solvent-based acid-curing coating composition according to claim 7, wherein, The polyester resin with a medium hydroxyl value has a number average molecular weight of 3500-4000, which is determined according to ASTM D6579-11.

9. The solvent-based acid-curing coating composition as described in claim 7 or 8, wherein, The at least one medium-hydroxyl polyester resin is present in an amount of 25-45 wt% relative to the total weight of the solvent-based acid-curing coating composition.

10. The solvent-based acid-curing coating composition according to any one of claims 1 to 9, wherein, The at least one hydroxyl-functionalized resin further comprises at least one high hydroxyl-value polyester resin in the range of 90 to 100 mg KOH / g, wherein the hydroxyl value is determined according to GB12009.3-2009, and preferably, the high hydroxyl-value polyester resin is present in an amount not exceeding 20 wt% relative to the total weight of the solvent-based acid-curing coating composition.

11. The solvent-based acid-curing coating composition according to any one of claims 1 to 5, wherein, The at least one amino resin is a reaction product of at least one aldehyde and at least one amino compound, wherein the at least one amino compound includes melamine, urea, benzomelamine, methylmelamine, or a combination thereof.

12. The solvent-based acid-curing coating composition according to claim 11, wherein, The at least one amino resin is etherified, preferably by etherification with n-butanol, isobutanol, methanol, or a combination thereof.

13. The solvent-based acid-curing coating composition according to any one of claims 1 to 5, wherein the at least one acid catalyst is selected from the group consisting of p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, dodecylbenzenesulfonic acid, oxalic acid, maleic acid, phthalic acid, acrylic acid, mono(di)alkyl phosphate, phosphoric acid, mono(di)alkyl pyrophosphate, or combinations thereof.

14. The solvent-based acid-curing coating composition according to any one of claims 1 to 13, wherein, The solvent-based acid-curing coating composition comprises, relative to the total weight of the solvent-based acid-curing coating composition. 25-65 wt% of the at least one hydroxyl-functionalized resin; 5-15 wt% of the at least one amino resin; 10-30 wt% of the at least one matting agent; 0.1-1 wt% of the at least one acidic catalyst; At least one solvent, 0.1-20 wt%; and 0-30 wt% of additional additives, said additional additives including at least one pigment, at least one filler, at least one anti-settling agent, at least one thickener, at least one dispersant, at least one wetting agent, at least one film-forming aid, at least one coupling agent, at least one bactericide, at least one fungicide, or any combination thereof.

15. The solvent-based acid-curing coating composition according to any one of claims 1 to 14, wherein, The solvent-based acid-curing coating composition has a solid content of 65% or higher.

16. The solvent-based acid-curing coating composition according to any one of claims 1 to 15, wherein, After the solvent-based acid-curing coating composition is applied to a substrate and cured, the resulting coating has a whiteness of 4.5 or higher, which is measured using a colorimeter.

17. The solvent-based acid-curing coating composition according to any one of claims 1 to 15, wherein, After the solvent-based acid-curing coating composition is applied to a substrate and cured, the resulting coating has a gloss of 60° not exceeding 45, which is determined by GB / T 1743-1989.

18. An article of manufacture comprising... Substrate, having at least one main surface; and A base coating applied directly or indirectly to at least a portion of the main surface of the substrate. A topcoat applied directly or indirectly onto the base coating. in, The topcoat is formed from the solvent-based acid-curing coating composition according to any one of claims 1-17.

19. The article of claim 18, wherein the substrate is selected from metal substrates, preferably including stainless steel, iron, aluminum, aluminum alloys or any combination thereof.

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