Water-based coating composition and coating and product formed by water-based coating composition

Abstract

The invention relates to an aqueous coating composition and a coating and an article formed therefrom. Specifically, the aqueous coating composition comprises: a component A comprising a film-forming resin composition, starch, an optional aqueous carrier and an additional additive, the starch being present in an amount of 2-20 wt%, preferably 4-10 wt%, with respect to the total weight of the component A, and the optional aqueous carrier being present in an amount of 2-20 wt%, preferably 4-10 wt%, with respect to the total weight of the component A; and wherein the coating formed by the aqueous coating composition has a 60 DEG gloss of not more than 5 DEG. The invention also relates to a coating and a product formed by the water-based coating composition, wherein the coating and the product have a tactile effect.

Description

[0001] This application is a divisional application of the invention patent application filed on January 27, 2021, with application number 202110116101.5 and invention title "A water-based coating composition and a coating and article formed therefrom". Technical Field

[0002] This invention relates to a water-based coating composition, and more particularly to a water-based coating composition capable of creating a tactile effect, as well as coatings and articles made therefrom. Background Technology

[0003] As people's living standards gradually improve, coatings are increasingly evolving towards greater comfort, style, and personalization. People's demands for product appearance are also rising, requiring not only vibrant colors but also a superior tactile experience. These demands are significantly increasing across various application areas, including consumer electronics (such as laptop and mobile phone cases), wooden furniture, home appliances (such as ovens and coffee machines), automotive interiors (such as panels, brackets, and armrests), clothing (such as athletic shoes), packaging (such as cosmetic bottles / caps and bags), and textured films for in-mold decoration / in-mold labeling (IMD / IML). In this context, ordinary coating compositions are insufficient to meet these high-end requirements.

[0004] Currently, besides attractive visual design, the focus of tactile coatings is also on the tactile experience of the final product. After applying a tactile coating, the resulting surface can achieve a variety of tactile sensations, including but not limited to a soft, sandpaper-like effect, a smooth, silky, or sticky effect, or a rough, sandpaper-like effect. Moreover, depending on the need, this tactile coating can be combined with appealing colors such as metallic, color-changing, or thermochromic finishes, as well as controllable matte or glossy surfaces, allowing for a high degree of design freedom. Therefore, the demand for tactile coatings in the coating industry is strong.

[0005] Currently, the number of coating compositions capable of forming tactile coatings on the market is very limited, far from meeting market demand. Therefore, there is an urgent need to develop a new type of coating composition capable of creating tactile effects to meet the aforementioned application requirements. Summary of the Invention

[0006] On one hand, the present invention provides an aqueous coating composition comprising: component A, including a film-forming resin composition, starch, optionally an aqueous carrier, and additional additives; wherein the starch is present in an amount of 2-20% by weight, preferably 4-10% by weight, relative to the total weight of component A, and wherein the coating formed by the aqueous coating composition has a gloss of 60° not exceeding 5°. In one embodiment of the invention, the aqueous coating composition is a one-component aqueous coating composition. In another embodiment of the invention, the aqueous coating composition further includes component B, making it a two-component aqueous coating composition.

[0007] On the other hand, the present invention provides a coating formed from the above-mentioned water-based coating composition, wherein the coating has a tactile effect.

[0008] On the other hand, the present invention also provides an article comprising: a substrate having at least one main surface; and at least one coating layer formed by directly or indirectly applying the above-described aqueous coating composition to the main surface. Preferably, the substrate comprises wood, metal, plastic, leather, fabric, ceramic, cement board, or any combination thereof.

[0009] The inventors of this invention were surprised to discover that by incorporating a certain amount of unmodified starch in powder form into conventional emulsions, particularly aqueous dispersions of polyurethane and / or aqueous dispersions of polyurethane-acrylic resins, a waterborne coating composition capable of achieving a tactile effect can be obtained. This greatly simplifies the preparation process of tactile coatings and expands the operational scope. The resulting waterborne coating composition not only preserves the original properties of the paint film but also improves the tactile effect and scratch resistance of the paint film, which was unforeseen before this application. In one embodiment of the invention, the coating formed by the coating composition according to the invention not only maintains excellent transparency and superior durability but also possesses a delicate, soft, and smooth tactile feel close to that of skin and / or an ultra-matte gloss (e.g., a gloss of 2-5° at 60°), as well as excellent hardness and / or scratch resistance.

[0010] 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.

[0011] definition 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.

[0012] 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.

[0013] When used in this specification and claims, the terms “comprising,” “including,” “containing,” and variations thereof are not restrictive.

[0014] In this article, "coating" and "paint film" have the same meaning, both referring to the formation of a water-based coating composition after it has been applied and dried.

[0015] In the context of this application, the term "tactile coating" refers to a coating that enables human skin to produce a certain tactile sensation (also simply referred to as tactile sensation). Tactile sensation is caused by the slight mechanical stimulation of receptors on the surface of human skin. Considering that these receptors vary from person to person, and that each person interprets tactile characteristics differently, the range of tactile sensations is generally quite broad, including but not limited to, smooth / soft effects, silky effects, rubbery and sticky effects, soft sandpaper-like effects, and rough sandpaper-like effects, etc.

[0016] When used in relation to "waterborne coating composition", the phrase "the coating formed by the waterborne coating composition has a gloss of not more than 5° at a 60-degree angle" means that the coating formed by the waterborne coating composition has a very low gloss effect, exhibiting ultra-matte performance.

[0017] When referring to "starch," the term "acidity" is a parameter used to measure the composition of starch products. Generally, the lower the acidity, the fewer impurities in the starch product and the better its quality.

[0018] When referring to "starch," the term "fineness" is a parameter used to measure the particle size of starch products. Generally, the higher the fineness, the less particle agglomeration and the narrower the particle distribution of the starch product.

[0019] In the context of this application, the term "amylose" refers to a starch that dissolves only slightly in hot water, does not readily form a paste, and whose solution redefines starch crystals upon standing. In contrast, the term "amylose" refers to a starch that readily dissolves in water, forms a stable paste, and whose solution does not precipitate upon standing. In one embodiment of the invention, the starch used is a mixture of amylose and amylopectin.

[0020] In the context of this invention, the term "feel agent" includes silicone feel agents, fluff powder, and wax emulsion feel agents. When used with respect to "waterborne coating compositions," the term "substantially free of feel agents" means that the components of the waterborne coating composition, and the coating composition formulated therein, do not contain any additional added feel agents as described above, preferably none known in the art. When the phrase "substantially free of" is used herein, such a phrase is not intended to exclude the presence of trace amounts of relevant feel agents that may be present as environmental contaminants or due to environmental pollution.

[0021] In the context of this invention, the term "matting agent" includes silica matting agents, synthetic wax matting agents, and stearate matting agents. In some embodiments of this invention, the waterborne coating composition is substantially free of matting agents. In this embodiment, the phrase "the waterborne coating composition is substantially free of matting agents" means that the components of the waterborne coating composition and the coating composition formed therefrom do not contain any additional added matting agents described above, preferably none known in the art. When the phrase "substantially free" is used herein, such a phrase is not intended to exclude the presence of trace amounts of matting agents that may be present as environmental contaminants or due to environmental pollution. In other embodiments of this invention, the waterborne coating composition may also contain matting agents.

[0022] When used in relation to "waterborne coating composition", the term "substantially free of" a certain component means that the waterborne coating composition of the present invention contains no more than 0.1% by weight, preferably no more than 0.05% by weight, and more preferably no more than 0.01% by weight of the component relative to the total weight of the waterborne coating composition.

[0023] In the context of this application, the term "one-component waterborne coating composition" refers to a waterborne coating composition that, on its own, can dry and cure to form a coating with desired mechanical properties (e.g., hardness) without the assistance of an additional curing agent.

[0024] In the context of this application, the term "two-component waterborne coating composition" refers to a waterborne coating composition consisting of two or more separately stored components that are mixed together upon use and can be dried and cured within an acceptable time period to form a coating with desired mechanical properties (e.g., hardness).

[0025] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an unspecified range.

[0026] 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.

[0027] 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. Detailed Implementation

[0028] According to an embodiment of the present invention, a waterborne coating composition is provided, comprising: component A, including a film-forming resin composition, starch, optionally a waterborne carrier, and additional additives; wherein, relative to the total weight of component A, the starch is present in an amount of 2-20% by weight, preferably 4-10% by weight, and wherein the coating formed by the waterborne coating composition has a gloss of 60° not exceeding 5°. In an embodiment of the present invention, component A of the waterborne coating composition contains a certain amount of starch. The inventors of the present invention have surprisingly discovered that a certain amount of unmodified starch in powder form can be incorporated into a conventional emulsion to form a waterborne coating composition, thereby obtaining a waterborne coating composition that not only preserves the original properties of the paint film but also improves the tactile effect and scratch resistance of the paint film, which was difficult to foresee before this application. Not bound by any theory, the inventors speculate that during the film-forming process, the starch in the waterborne coating composition formed above is uniformly distributed on the surface of the paint film along with the flow of the emulsion, forming an extremely thin, soft starch coating, thus resulting in a coating that exhibits a tactile effect.

[0029] As is well known, determining the tactile properties of coatings has always been a challenging task. Tactile sensation is caused by the slight mechanical stimulation of receptors on the surface of human skin. Considering that receptors vary from person to person, each individual interprets tactile characteristics differently, resulting in a wide range of tactile sensations. These tactile effects include, but are not limited to, smooth / soft, silky, rubbery and sticky, soft sandpaper-like, and rough sandpaper-like effects, etc. When determining the tactile properties of a coating, it is important that the determination be performed by trained observers who have typically touched coatings with recognized tactile effects. In some embodiments of the invention, the tactile properties of coatings formed from the waterborne coating composition according to the invention are determined by the tactile performance testing method described in the Examples section, and are graded from 1 to 5, with higher grades indicating more easily perceived tactile effects. In one embodiment of the invention, the coating formed from the waterborne coating composition according to the invention has a tactile effect of grade 4 or higher. Preferably, the coating formed from the waterborne coating composition according to the invention has a tactile effect of grade 4.5 or higher. More preferably, the coating formed from the waterborne coating composition according to the invention has a tactile effect of grade 5.

[0030] The coating formed by the water-based coating composition according to the present invention, in addition to the above-mentioned tactile effects, also has a 60-degree gloss angle of no more than 5°, exhibiting an ultra-matte effect. Preferably, the paint film formed by the water-based coating composition according to the present invention preferably has a 60-degree gloss angle of no more than 4.5°, more preferably has a 60-degree gloss angle of no more than 4°, even more preferably has a 60-degree gloss angle of no more than 3.5°, and even more preferably has a 60-degree gloss angle of no more than 3°. In contrast, conventional coatings with ultra-matte properties on the market do not simultaneously possess both an ultra-matte effect and a tactile effect.

[0031] The ultra-matte effect of the coating produced by the water-based coating composition according to the present invention is surprising. In the coating industry, it is usually necessary to add a certain amount of matting agent to the coating composition to obtain a coating with ultra-matte properties. However, the inventors of the present invention have discovered that the water-based coating composition according to the present invention, due to the presence of a certain amount of starch, can achieve an ultra-matte effect with virtually no matting agent, that is, the coating formed by the water-based coating composition can have a gloss of 60° not exceeding 5°. Coatings with a gloss of 60° not exceeding 5° are also referred to as coatings with ultra-matte properties and are a type of product urgently needed in the coating industry. GB1157040 discloses a coating composition for wallpaper, wherein the coating formed by the coating composition has a gloss of less than 16%, preferably less than 11%, at a 45-degree angle. However, in the coating industry, achieving a gloss of ≤5% at a 60-degree angle is much more difficult than achieving a gloss of <11% at a 45-degree angle, which is determined by the optical geometry measured at different angles. When measured at a 45-degree angle, the incident light is relatively perpendicular, limiting the ability to capture surface micro-undulations. Therefore, it has some reference value when evaluating "semi-gloss" or "medium gloss," but its sensitivity is extremely poor in the very low gloss (matte) range. The 60-degree angle test is considered a "general standard angle for medium / low gloss." Due to the longer incident light path, the interaction volume between the light and the coating surface is larger. When measured at 60 degrees, any minute fluctuations in surface smoothness or inconsistencies in refractive index will be amplified. According to ISO 2813 and ASTM D523, 60° is the general reference angle for evaluating coating gloss. Especially for matte surfaces, 60° is the dividing line between "low gloss" and "deep matte." As the incident angle increases (from 45° to 60°), the light more easily captures extremely subtle surface imperfections. Therefore, coatings with less than 11% gloss at 45° will have their minute specular reflections amplified when measured at 60°, as the light path is closer to the surface. The coating formed by the water-based coating composition according to the present invention achieves a gloss level of <5% even at a more "demanding" angle of 60°, demonstrating the excellent performance of the coating. For those skilled in the art of coatings, a gloss level of ≤5% at a 60° angle is not merely a simple numerical optimization of <11% at a 45° angle, but a qualitative leap in performance. Therefore, in some embodiments of the present invention, the water-based coating composition is substantially free of matting agents; preferably, the water-based coating composition is free of matting agents, and the coating formed by the water-based coating composition has a gloss level of 60° within the range of 3° to 5°.

[0032] Furthermore, the inventors of this invention have surprisingly discovered that adding a certain amount of matting agent to the waterborne coating composition according to the invention can further reduce the gloss of the coating formed therefrom. Therefore, in some embodiments of the invention, the waterborne coating composition contains a matting agent, preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and more preferably 1 wt% or more, relative to the total weight of the waterborne coating composition, such that the coating formed by the waterborne coating composition has a gloss of 60° with a gloss level not exceeding 3°.

[0033] In an embodiment of the invention, the starch is present in an amount of 2-20% by weight, preferably 4-10% by weight, relative to the total weight of component A. The amount of starch within the above range is appropriate. If the amount of starch is too high, the resulting waterborne coating composition will have excessive viscosity and will not easily form a film; if the amount of starch is too low, the resulting waterborne coating composition will not exhibit sufficient tactile effect. In some embodiments of the invention, the starch is present in an amount of 2-18 wt%, 2-15 wt%, 2-12 wt%, 2-10 wt%, 2-9 wt%, 2-8 wt%, 2-7 wt%, 2-6 wt%, 2-5 wt%, 3-10 wt%, 3-9 wt%, 3-8 wt%, 3-7 wt%, 3-6 wt%, 3-5 wt%, 4-10 wt%, 4-9 wt%, 4-8 wt%, 4-7 wt%, 4-6 wt%, 4-5 wt%, 5-10 wt%, 5-9 wt%, 5-8 wt%, 5-7 wt%, 5-6 wt%, or in an amount within any of the values ​​described above.

[0034] In some embodiments of the invention, the starch has a low acidity, for example, less than or equal to 2.0, where acidity refers to the number of milliliters of a 0.1 mol / L sodium hydroxide aqueous solution consumed to neutralize 10 grams of anhydrous starch. As mentioned above, acidity is a parameter used to measure the composition of a starch product. The acidity is tested by titration according to GB / T8885-2008. The inventors of the present invention have found that the acidity of starch can have a certain impact on the tactile effect of the coating formed by the water-based coating composition. Starch with low acidity is preferred. More preferably, the acidity of the starch is 1.5 or less, for example, 1.49 or less, 1.48 or less, or 1.47 or less.

[0035] In some embodiments of the invention, the starch has a small particle size, for example, a fineness of 99.5% or higher that passes through a 100-mesh sieve. As mentioned above, fineness is a parameter used to measure the particle size of a starch product. The fineness is determined according to GB / T8885-2005 as the percentage of starch product passing through a sieve of a specific mesh size. The inventors of the present invention have found that incorporating a starch product with a high fineness into an aqueous coating composition is advantageous for forming a coating with a tactile effect. Therefore, in a preferred embodiment of the invention, the starch has a fineness of 99.7% that passes through a 100-mesh sieve, more preferably 99.9%.

[0036] In some embodiments of the invention, the starch comprises amylose, amylopectin, or a combination thereof. Preferably, the starch comprises a mixture of amylose and amylopectin. In a preferred embodiment, the starch comprises amylose in a content ranging from 20% to 40% by weight relative to the total weight of the starch, and amylopectin in a content ranging from 60% to 80% by weight. The inventors of the present invention have found that incorporating starch formed from the above-mentioned proportions of amylose and amylopectin into an aqueous coating composition is advantageous for forming a coating with a tactile effect. If the content of amylose is too high, the starch has low solubility in the aqueous coating composition and is prone to sedimentation, which is not conducive to forming a stable aqueous coating composition; if the content of amylose is too low, the starch is difficult to crystallize during the film-forming process of the aqueous coating composition to form a stable starch layer, which is not conducive to obtaining a coating with a tactile effect. Therefore, in a preferred embodiment of the invention, starch having the above-mentioned composition is preferred. In a particularly preferred embodiment of the invention, the starch comprises amylose in a content ranging from 25% to 32% by weight relative to the total weight of the starch, and amylopectin in a content ranging from 68% to 75% by weight.

[0037] In some embodiments of the present invention, the starch is selected from one or more of corn starch, potato starch, wheat starch, rice starch, cassava starch, oat starch, and sorghum starch, preferably from one or more of corn starch, cassava starch, or potato starch, and more preferably from corn starch.

[0038] In embodiments of the invention, component A is the composition constituting the main body of the coating formed by the aqueous coating composition, which can be dried, crosslinked, or otherwise hardened on its own or as needed with a suitable curing agent, thereby forming a non-sticky continuous film on the substrate. In addition to the starch described above, component A also includes a film-forming resin composition, optional aqueous carrier, and additional additives.

[0039] In some embodiments of the invention, the film-forming resin composition is present as an aqueous dispersion of polymer particles. When used herein, the term "aqueous dispersion of polymer particles" refers to a stable dispersion of a synthetic resin (i.e., a polymer) in particulate form in an aqueous liquid medium, optionally with the aid of a suitable dispersing agent such as a surfactant. Therefore, in this application, when referring to a polymer, the terms "aqueous latex" and "aqueous dispersion" may be used interchangeably unless otherwise stated. Methods for preparing aqueous latex are known in the art, for example, they can be carried out using emulsion polymerization processes known to those skilled in the art. Such emulsion polymerization processes typically include the steps of dispersing polymerizable monomers into an emulsion in water, optionally with the action of a suitable emulsifier and / or dispersant stabilizer and by means of stirring, and initiating the polymerization of the monomers, for example, by adding an initiator.

[0040] It is known that polymer particles in aqueous latex can be modified to obtain aqueous latex with desired properties. In one embodiment of the invention, the polymer particles are modified by active hydrogen functional groups. On one hand, active hydrogen can be provided by functional groups such as -COOH, -OH, -SH, secondary amino, and primary amino groups. Furthermore, some functional groups, such as ester groups (especially carboxylic acid ester groups), thioether groups, or anhydride groups (especially carboxylic acid anhydride groups), can be converted, for example, by hydrolysis into functional groups capable of providing active hydrogen. Therefore, in the present invention, polymer particles having one or more active hydrogen functional groups refer to any polymer particles that inherently contain functional groups capable of providing active hydrogen and / or any polymer particles that can be converted into functional groups capable of providing active hydrogen during system preparation and / or application.

[0041] In embodiments of the invention, the aqueous dispersion of polymer particles is considered as a film-forming resin composition in an aqueous coating composition. On one hand, this resin composition acts as a binder, providing adhesion between the coating film and the substrate, and holding the components (such as fillers) in the aqueous coating composition together and imparting a certain cohesive strength to the coating film. On the other hand, these polymer particles can react with a suitable curing agent as needed to achieve cross-linking of the polymer chains, thereby achieving a coating with high mechanical strength.

[0042] In some embodiments of the present invention, the polymer particles in the aqueous latex may have one or more active hydrogen functional groups selected from -COOH, -OH, -SH, secondary amino and primary amino groups.

[0043] In some preferred embodiments of the present invention, the aqueous dispersion of the polymer particles includes one or more of the following: aqueous dispersions of acrylic resins, aqueous dispersions of polystyrene-acrylic resins, aqueous dispersions of polyurethanes, aqueous dispersions of polyurethanes-acrylic resins, aqueous dispersions of epoxy resins, aqueous dispersions of polyesters, aqueous dispersions of polyvinyl acetate, and aqueous dispersions of polysiloxanes. Preferably, it includes one or two of the following: aqueous dispersions of acrylic resins, aqueous dispersions of polystyrene-acrylic resins, aqueous dispersions of polyurethanes, and aqueous dispersions of polyurethanes-acrylic resins. More preferably, it includes one or two of the following: aqueous dispersions of polyurethanes and aqueous dispersions of polyurethanes-acrylic resins.

[0044] In embodiments of the invention, the polymer particles in the aqueous dispersion have a range of particle sizes, which can be measured using Z-average particle size, a term known in the art, referring to the particle size measured using dynamic light scattering methods, such as a Marvlen Zetasizer 3000HS microparticle size analyzer. Preferably, the polymer particles in the aqueous dispersion can have a particle size in the range of 50 nm to 200 nm. The inventors of the invention have surprisingly discovered that aqueous dispersions of polymer particles having the above-mentioned particle size range are particularly suitable for formulating aqueous coating compositions, which exhibit suitable rheological properties and coatability.

[0045] In embodiments of the present invention, the aqueous dispersion of the polymer particles has a solid content of 30-50%. From an industrial perspective, an aqueous dispersion of polymer particles with the above-mentioned solid content is the most readily available. The above-mentioned aqueous dispersion of polymer particles can be prepared in-house or is a commercially available product. As an example, commercially available aqueous dispersions of Dow 3311 acrylates, Allnex 6716 acrylates, DSM E129 polyurethane polyacrylate, DSM R2180 polyurethane, or Alberdingk U9900 polyurethane can be used.

[0046] According to embodiments of the present invention, the amount of the aqueous dispersion of polymer particles can vary over a wide range, and its total amount relative to the total weight of component A can range from about 60 wt% to about 85 wt%. In some embodiments, the amount of the aqueous dispersion of polymer particles can range from 75 wt% to 85 wt%.

[0047] In some embodiments according to this application, the waterborne coating composition is a one-component coating composition containing only component A as described above, said component A comprising a film-forming resin composition, starch, optional waterborne carrier, and additional additives. In these embodiments, component A can be cured into a film by, for example, self-crosslinking or latex entanglement.

[0048] In some other embodiments according to this application, the waterborne coating composition is a two-component coating composition comprising component A and component B as described above. Component A includes a film-forming resin composition, starch, optional waterborne carrier, and additional additives, and component B includes a curing agent. Before application, component A and component B are mixed, and then the coating is applied. The type of curing agent depends on the nature of the resin composition. Coating compositions containing amino and / or hydroxyl functional resins preferably use isocyanates and isocyanurates as curing agents. Suitable isocyanate curing agents are aliphatic, alicyclic, and aromatic polyisocyanates, such as trimethylene diisocyanate, 1,2-propylene diisocyanate, tetramethylene diisocyanate, 2,3-butylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, etc. 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′-tetramethyl-o-, 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 isocyanates and their adducts may be present in the form of end-capped or latent isocyanates.

[0049] In the two-component waterborne coating composition according to this application, the amount of curing agent as component B can be adjusted based on the amount of component A, particularly the amount of film-forming resin composition in component A, according to the experience of those skilled in the art. In some embodiments of this application, the weight ratio of component A to component B as curing agent is in the range of 100:5 to 100:20, for example, 100:15, 100:23, or other commonly used ratios of component A to component B in the art.

[0050] In embodiments of this application, an aqueous carrier is optional in the formulation of the aqueous coating composition. As an example, aqueous carriers include, but are not limited to, water, alcohol solvents (e.g., methanol, isopropanol, isobutanol, n-propanol, n-butanol, 2-butanol, pentanol, tert-pentanol, neopentanol, n-hexanol, ethylene glycol, etc.), ketone solvents (e.g., acetone, methyl ethyl ketone, methyl n-pentyl ketone, etc.), ether solvents (e.g., ethylene glycol butyl ether, etc.), etc. In some embodiments of this application, the aqueous coating composition may not contain an additional aqueous carrier. In some embodiments of the invention, the aqueous coating composition may further contain a certain amount of aqueous carrier to obtain a suitable coating viscosity.

[0051] According to embodiments of the present invention, the amount of the aqueous carrier can vary over a wide range, and its total amount relative to the total weight of component A can range from about 10 wt% to about 25 wt%. In some embodiments, the amount of the aqueous carrier can range from 15 wt% to 20 wt%.

[0052] According to some embodiments of the invention, the waterborne coating composition may further comprise pigments and fillers, as needed, to impart the desired color and / or strength to the resulting paint film or coating. The term "pigment and filler" as used herein refers to any volume-increasing agent suitable for coatings, which may be organic or inorganic, for example, in particulate form. There are no particular limitations on the shape of the particles, which may have any suitable shape. The average particle size can vary over a wide range, for example, from about 10 nanometers to about 50 micrometers. Some particulate materials, in addition to acting as volume-increasing agents in the coating, impart one or more desired properties to the composition and / or the coating formed from the composition. For example, some particulate materials can impart a desired color to the composition and the coating obtained from the composition. In this case, such particulate materials are also referred to as "pigments". Some particulate materials can improve chemical and / or physical properties, particularly the mechanical properties of the coating obtained from the composition. In this case, such particulate materials are also referred to as "fillers".

[0053] In embodiments of the present invention, suitable exemplary pigments and fillers include, for example, kaolin, titanium dioxide, calcium carbonate, diatomaceous earth, talc, barium sulfate, magnesium aluminum silicate, silicon dioxide, and any combination thereof. In a preferred embodiment, the filler may include titanium dioxide, kaolin, calcium carbonate, diatomaceous earth, or a combination thereof.

[0054] According to the invention, the total amount of pigments and fillers can vary over a wide range, for example, from about 0% to about 10% by weight relative to the total weight of component A, preferably from about 0.1% to about 8% by weight, more preferably from about 0.5% to about 5% by weight. In some preferred embodiments of the invention, the waterborne coating composition contains no pigments or fillers and is present in the form of a clear varnish. According to embodiments of the invention, the waterborne coating composition may optionally further include other additional additives commonly used in waterborne coating compositions, which do not adversely affect the coating composition or the cured coating obtained therefrom. Suitable additives include, for example, those agents that improve the processing or manufacturing properties of the composition, enhance the aesthetics of the composition, or improve specific functional properties or characteristics (such as adhesion to the substrate) of the coating composition or the cured composition obtained therefrom. Additional additives that may be included include, for example, cosolvents, defoamers, leveling agents, thickeners, lubricants, anti-migration agents, fungicides, preservatives, wetting agents, antifungal and bactericidal agents, rust inhibitors, antioxidants, dispersants, adhesion promoters, UV stabilizers, pH adjusters, film-forming aids, or combinations thereof. The amounts of each optional component are sufficient to achieve the intended purpose, but preferably, such amounts will not adversely affect the waterborne coating composition or the resulting paint film. In some embodiments of the invention, the waterborne coating composition may further comprise one or more of a cosolvent, defoamer, leveling agent, thickener, surfactant, and bactericide. In one embodiment of the invention, the waterborne coating composition may further comprise one or more of a cosolvent (including but not limited to dipropylene glycol monomethyl ether (DPM) and dipropylene glycol monobutyl ether (DPnB)), leveling agent, and thickener.

[0055] According to the present invention, the total amount of the additional additives can vary within an appropriate range, for example, the total amount of which is about 0% to about 15% by weight relative to the total weight of component A, preferably about 0.1% to about 12% by weight, more preferably about 1% to about 12% by weight.

[0056] In one specific embodiment of the present invention, component A of the water-based coating composition comprises, relative to the total weight of component A, 55-80% by weight of film-forming resin composition; 2-5% by weight of starch; 10-25% by weight of aqueous carrier; and Additional additives: 0-15% by weight.

[0057] The preparation of the waterborne coating composition according to the present invention can be achieved by any suitable mixing method known to those skilled in the art. For example, the waterborne coating composition can be prepared by adding a film-forming resin composition, starch, an aqueous carrier (if any), and additional additives (if any) to a container, and then stirring the resulting mixture until homogeneous to form component A. The curing agent, as component B, can be present as a single component or, if desired, can be mixed with the components other than the film-forming resin composition to form a mixture.

[0058] The waterborne coating composition of the present invention can be applied by conventional methods known to those skilled in the art, such as by scraping, spraying, rolling or other conventional coating methods known to those skilled in the art.

[0059] The inventors of this application were surprised to find that the water-based coating composition prepared as described above can achieve excellent tactile effects when used as a topcoat. Therefore, in another aspect, the present invention provides a coating formed from the water-based coating composition according to the present invention, exhibiting tactile effects.

[0060] In one embodiment of the invention, after the water-based coating composition was applied to a test panel with a wet film thickness of 150 micrometers and air-dried for 7 days, the resulting coating film exhibited a delicate and soft feel close to that of skin when tested using the tactile performance test method described in the Examples section.

[0061] In another aspect, the present invention also provides an article comprising: a substrate having at least one main surface; and at least one coating layer, said coating film being formed by an aqueous coating composition according to an embodiment of the present invention, applied directly or indirectly to said main surface.

[0062] In embodiments of the articles of the present invention, the substrate may be any suitable substrate, including but not limited to: wood, metal, plastic, leather, fabric, ceramic or any combination thereof.

[0063] According to this application, the article can be prepared, for example, by the following steps: (1) providing a substrate; (2) using a coating and curing process to sequentially coat and form one or more layers of an aqueous coating composition according to this application on the substrate to provide a tactile effect to the substrate.

[0064] According to this application, the articles obtained therefrom can be used in a variety of end applications, including, but not limited to: consumer electronics (e.g., laptops, mobile phone cases), wooden furniture, home appliances (e.g., ovens, coffee machines), automotive interiors (e.g., panels, brackets, armrests), clothing (sports shoes), packaging (e.g., cosmetic bottles / caps, bags), and textured films for in-mold decoration / in-mold labeling (IMD / IML).

[0065] Example 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.

[0066] Tactile performance: A water-based coating composition was applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days. Samples thus formed were distributed to five trained observers, three samples per observer. The five observers touched each sample by hand to assess the tactile properties of the surface. A sample was deemed to have a tactile effect if the observer perceived at least one of the following effects: smooth / soft, silky, rubbery and sticky, soft sandpaper-like, and rough sandpaper-like; otherwise, the sample was deemed not to have a tactile effect. Furthermore, the tactile effect could be further subdivided into five levels: 1 for "very weak tactile effect"; 2 for "slight tactile effect"; 3 for "moderate tactile effect"; 4 for "obvious tactile effect"; and 5 for "significant tactile effect". The tactile effect of each sample was then obtained by averaging the above tactile effect levels.

[0067] Glossiness: A water-based coating composition was applied to an aged polyurethane panel at a wet film thickness of 150 micrometers and air-dried for 7 days. The gloss of the sample was then tested using a BYK4565 micrometer gloss meter. o Glossiness.

[0068] Scratch resistance: The scratch resistance of the samples was tested according to GB / T9279-2007 after the water-based coating composition was applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days.

[0069] transparency:The water-based coating composition was applied to a glass panel with a wet film thickness of 150 micrometers and air-dried for 7 days. After visual comparison testing, the results were scored, with 5 points being the best and 1 point being the worst.

[0070] Chemical resistance The water-based coating composition was applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days. The chemical resistance of the water-based coating composition was tested according to the test standards GB / T 3324-2008 and GB / T 23999-2009 and scored. A grade of 5 indicates the best chemical resistance and 0 indicates the worst chemical resistance.

[0071] Raw materials: Aqueous polyurethane dispersion: TT-340 ALBERDINGK Polyurethane-polyacrylate aqueous dispersion E-129 The corn starch has an acidity of 1.47, a fineness of 99.9%, and contains 26.5% to 30.26% amylose; it was purchased from Hebei Yufeng Starch and Sugar Industry Group. Tapioca starch, with an acidity of 1.48 and a fineness of 99.8%, containing 15% to 19% amylose; purchased commercially from Xinxiang Xinliang Grain and Oil Processing Co., Ltd. Potato starch with an acidity of 1.48 and a fineness of 99.7%, containing 17% to 23% amylose; purchased commercially from Xinxiang Xinliang Grain and Oil Processing Co., Ltd. Cosolvents DPM DOW, DPNB DOW Other additives: Defoamer BYK-024 / BYK-028 BYK, Leveling agent TWIN 4100 TEGO, Thickener PUR44 / PUR80 TAFIGEL Commercially available skin-feel paint: Carpoly water-based skin-feel paint.

[0072] Commercially available ultra-matte paint: Jiadebaoman full matte topcoat.

[0073] Waterborne coating composition As shown in Table 1, the components in the indicated amounts were mixed to form the waterborne coating compositions according to Examples 1-3 and Comparative Example 1 of this application, wherein Examples 1-3 are waterborne coating compositions containing corn starch, tapioca starch and potato starch, respectively; Comparative Example 1 does not contain any starch; Comparative Example 2 is substantially the same as Example 3, except that it uses AVEBE Solvicol (a potato starch derivative commercially available from the Dutch company AVEBE ba) with an acidity of 2.6; Comparative Example 1 is a commercially available skin-feel paint: Carpoly waterborne skin-feel paint; Comparative Example 2 is a commercially available ultra-matte paint: Jiadebaoman full matte paint.

[0074] Table 1: Composition and Dosage of Waterborne Coating Compositions Coating performance The water-based coating compositions obtained in Examples 1-3, Comparative Example 1, and Comparative Examples 1-2 were sprayed onto the surface of a support substrate with a wet coating thickness of 150 micrometers and air-dried for 7 days. The tactile effect, gloss, transparency, scratch resistance, and chemical resistance of the samples were then measured according to the methods described in the aforementioned test section. The results are summarized in Table 2 below.

[0075] Table 2: Coating Performance As shown in Table 2, incorporating a certain amount of low-acidity starch into conventional emulsions, particularly a mixture of aqueous dispersions of polyurethane and polyurethane-acrylic resins, yielded an aqueous coating composition with a delicate and soft tactile feel similar to that of skin and an ultra-matte finish. Its tactile feel is comparable to that of currently commercially available tactile coatings, and its gloss is comparable to, or even better than, that of commercially available ultra-matte coatings. Furthermore, the coating formed by the aqueous coating composition according to the present invention exhibits significantly superior scratch resistance compared to coatings formed by commercially available tactile coating compositions.

[0076] Compared to coating compositions formulated with low-acidity starch, the incorporation of high-acidity starch leads to decreased film-forming stability. During film formation, an acidity greater than 2.0 causes uncontrolled degradation of starch molecular chains during the drying stage, resulting in uneven stress within the film layer and a high susceptibility to microcracks. Consequently, the resulting coating exhibits not only reduced scratch resistance and chemical resistance but also matte finish failure. The presumed reason is that acidic groups cause excessive degradation of starch chains during drying, resulting in a microscopically irregular, non-ordered diffuse reflection structure in the film. Its micro-roughness cannot be precisely controlled within the matte finish range, leading to enhanced local specular reflection and preventing the gloss level from falling below 5% at 60°. Therefore, modification by incorporating low-acidity starch fundamentally alters the performance of the coating composition.

[0077] Although the present invention has been described with reference to numerous embodiments and examples, it will be readily apparent to those skilled in the art that modifications can be made to the invention without departing from the principles disclosed in the foregoing description. For example, combining multiple features or preferred embodiments described herein without departing from the principles disclosed in the foregoing description should be understood as part of the scope of this description. Such modifications are considered to be included in the following claims unless expressly specified otherwise. Accordingly, the embodiments detailed herein are merely exemplary and not intended to limit the scope of the invention, which is the full scope of the appended claims and any and all equivalents.

Claims

1. A water-based coating composition comprising: Component A comprises a film-forming resin composition, starch, optional aqueous carrier, and additional additives; wherein, The starch is present in an amount of 2-20% by weight relative to the total weight of component A, preferably in an amount of 4-10% by weight, and The coating formed by the water-based coating composition has a gloss level of 60° with a gloss level not exceeding 5°.

2. The water-based coating composition according to claim 1, wherein, The starch has an acidity of less than or equal to 2.0, more preferably less than 1.5, wherein the acidity refers to the number of milliliters of a 0.1 mol / L sodium hydroxide aqueous solution consumed to neutralize 10 grams of anhydrous starch.

3. The water-based coating composition according to claim 1, wherein, The starch has a fineness of 99.5% or higher that can pass through a 100-mesh sieve, preferably 99.7% or higher, and more preferably 99.9% or higher.

4. The water-based coating composition of claim 1, wherein the starch comprises amylose, amylopectin, or a mixture thereof.

5. The waterborne coating composition of claim 4, wherein the starch comprises amylose in a content ranging from 20% to 40% by weight.

6. The water-based coating composition of claim 1, wherein the starch is selected from one or more of corn starch, potato starch, wheat starch, rice starch, cassava starch, oat starch and sorghum starch, preferably selected from one or more of corn starch, cassava starch and potato starch.

7. The waterborne coating composition according to any one of claims 1 to 6, wherein, The film-forming resin composition comprises one or more of the following: aqueous dispersions of acrylic resins, aqueous dispersions of polystyrene-acrylic resins, aqueous dispersions of polyurethanes, aqueous dispersions of polyurethanes-acrylic resins, aqueous dispersions of epoxy resins, aqueous dispersions of polyesters, aqueous dispersions of polyvinyl acetate, and aqueous dispersions of polysiloxanes. Preferably, it is selected from one or more of the following: aqueous dispersions of acrylic resins, aqueous dispersions of polystyrene-acrylic resins, aqueous dispersions of polyurethanes, and aqueous dispersions of polyurethanes-acrylic resins. More preferably, it is selected from one or two of the following: aqueous dispersions of polyurethanes and aqueous dispersions of polyurethanes-acrylic resins.

8. The waterborne coating composition according to any one of claims 1 to 6, wherein, Relative to the total weight of component A, component A comprises, 55-80% by weight of film-forming resin composition; 2-10% by weight of starch; 10-25% by weight of aqueous carrier; and Additional additives: 0-15% by weight.

9. The waterborne coating composition according to any one of claims 1 to 6, wherein, The water-based coating composition is substantially free of feel-enhancing agents.

10. The waterborne coating composition according to any one of claims 1 to 6, wherein, The water-based coating composition is substantially free of matting agents, and the coating formed by the water-based coating composition has a gloss of 60° in the range of 3° to 5°.

11. The waterborne coating composition according to any one of claims 1 to 6, wherein, The water-based coating composition contains a matting agent, and the coating formed by the water-based coating composition has a gloss level of 60° with a gloss level not exceeding 3°.

12. The waterborne coating composition according to any one of claims 1 to 6, further comprising component B, said component B comprising a curing agent.

13. A coating formed from the water-based coating composition according to any one of claims 1-12, wherein, The coating has a tactile effect.

14. An article comprising Substrate, having at least one main surface; and At least one coating layer, said coating layer being formed by applying directly or indirectly to the main surface the aqueous coating composition of any one of claims 1-12.

15. The article of claim 14, wherein, The substrate includes wood, metal, plastic, leather, fabric, ceramic, or any combination thereof.

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