Durable high-heat-resistance ceramic coating

Abstract

The present disclosure provides a coating composition that can be applied to a surface of a substrate to form a durable non-stick coating. The coating composition can include a silicone sol, a silicone polyester resin, and a silicone oil. The present invention relates to an organosilica sol capable of being formed by a sol-gel reaction comprising: at least two siloxane monomers; a catalyst; and optionally colloidal silica.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to International Patent Application No. PCT / CN2023 / 095496, filed on May 22, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a durable and heat-resistant coating composition for cookware or baking utensils, a method for preparing the coating composition, and a method for coating a substrate with the coating composition. Background Technology

[0004] Heat-resistant coatings are applied to substrates such as cookware, baking utensils, or other cooking appliances to provide functions such as aiding heat transfer, providing a non-stick release surface, and / or providing decorative color or aesthetic finish. Existing coating compositions have used fluoropolymers that may contain per- or polyfluoroalkyl substances (PFAS) as binders or release agents. PFAS (including fluoropolymers) as components of substances and / or mixtures are increasingly attracting regulatory attention. Summary of the Invention

[0005] This disclosure provides a method for forming a coating composition, comprising: hydrolyzing and condensing at least two different siloxane monomers with a catalyst to form an organosilica sol, the siloxane monomers having the following formula: R x Si(OR') 4-x , wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and the organosilica sol is combined with: silicone polyester resin; and silicone oil.

[0006] This disclosure further provides a coating composition comprising: a silicone polyester resin; a silicone oil; and an organosilica sol comprising at least two different siloxane monomers and catalyst hydrolysis and condensation reaction products, wherein the siloxane monomers have the following formula: R x Si(OR') 4-x , wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and liquid medium.

[0007] This disclosure further provides an article comprising a coating. The coating comprises a cured composition of a coating composition comprising: a silicone polyester resin; a silicone oil; and an organosilica sol comprising at least two different siloxane monomers as hydrolysis and condensation products of a catalyst, the siloxane monomers having the following formula: R x Si(OR') 4-x , wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and liquid medium.

[0008] Furthermore, this disclosure provides a method for coating an article with a coating composition, comprising: applying a coating composition comprising an organosilica sol, a silicone polyester resin, and a silicone oil onto a substrate, wherein the organosilica sol comprises at least two different siloxane monomers as hydrolysis and condensation reaction products with a catalyst, the siloxane monomers having the following formula: R x Si(OR') 4-x Wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and the coating composition is cured at a temperature of 100°C to 450°C. Attached Figure Description

[0009] The above and other features and advantages of this disclosure, as well as the ways in which they are obtained, will become more apparent from the following description taken in conjunction with the accompanying drawings, and the disclosure itself will be better understood. The above and other features of this disclosure can be used in any combination or arrangement.

[0010] Figure 1 An example is shown of a substrate coated with the coating composition of the present disclosure;

[0011] Figure 2 An example is shown of a substrate coated with the primer and top coat compositions of this disclosure; and

[0012] Figure 3 The diagram illustrates the thermosetting behavior of the coating compositions of this disclosure and comparative coating compositions.

[0013] In the various views, corresponding reference numerals denote corresponding parts. The examples illustrated herein illustrate this disclosure, and such examples should not be construed as limiting the scope of this disclosure in any way. Detailed Implementation

[0014] This disclosure provides a durable and heat-resistant coating composition comprising an organosilica sol, a silicone polyester resin, and a silicone oil. The coating composition can be applied to a substrate as a single layer or as a multilayer system comprising a primer and an outer coating.

[0015] I. Definition

[0016] For the purposes of the following detailed description, it should be understood that this disclosure may take various alternative variations and sequences of steps unless the contrary is explicitly stated. Furthermore, except in any operational instance, or where otherwise indicated, all figures used in the specification and claims to indicate, for example, the quantity of an ingredient, should be understood to be modified by the term "about" in all cases. For example, numerical ranges provided for the weight percentage of a component or the amount of added component should be interpreted as being modified by the term "about." Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations that can be varied according to the desired properties to be obtained through this disclosure. At least, and not in an attempt to limit the application of the equivalence principle to the scope of the claims, each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying common rounding techniques.

[0017] Although the numerical ranges and parameters described in this disclosure are approximate, the values ​​illustrated in specific examples are reported as precisely as possible. However, any numerical value inherently contains some error that is necessarily caused by the standard deviation found in its corresponding test measurement results.

[0018] Furthermore, it should be understood that any numerical range described herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges from the stated minimum value of 1 to the stated maximum value of 10 (and include both the minimum and maximum values), that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0019] Unless otherwise specified, the use of the singular includes the plural and the plural encompasses the singular. Furthermore, unless otherwise specified, the use of "or" means "and / or," even if "and / or" may be explicitly used in certain instances.

[0020] As used herein, a “wet” coating composition refers to an uncured coating composition.

[0021] As used herein, a "dry" coating composition refers to a cured coating composition.

[0022] As used herein, “substrate” and “article” refer to an object or other article having a surface on which a coating composition can be applied.

[0023] "Solids" refers to non-volatile components present in a composition of volatile and non-volatile components. As used herein, weight percentages based on "solids" refer to the amount of component based on the total weight of non-volatile components in the composition.

[0024] "Resin solids" refers to the solid components of the binder or film-forming components of the composition, as well as any optional crosslinking agents present. As used herein, a weight percentage based on "resin solids" means the amount of the component based on the total weight of the binder or film-forming components of the composition.

[0025] "Siloxane monomer" refers to a monomer containing silicon atoms having one or more Si-OR bonds (where R is an organic group), which can react with other such monomers via hydrolysis and condensation to form silicone resins with Si-O-Si bonds.

[0026] II. Organosilica sol

[0027] Organosilica sols can be prepared via a sol-gel reaction. The sol-gel reaction includes a hydrolysis step and a condensation step to form a silica matrix.

[0028] Organosilica sol may contain at least two siloxane monomers, such as organosilica alkane having the following general formula:

[0029] RxSi(OR')4-x

[0030] Where R is an aryl or alkyl organic substituent having up to 10 carbon atoms;

[0031] OR' is an alkoxy substituent having up to 5 carbon atoms (wherein the alkoxy substituent can have 1, 2, 3, 4, or 5 carbon atoms); and

[0032] x is an integer ranging from 0 to 3 (where x can be 0, 1, 2 or 3).

[0033] Siloxane monomers can be hydrolyzed and condensed in the presence of colloidal silica, water, and a catalyst.

[0034] The organosilica sol disclosed herein may have a molecular weight (Mw) of 500 g / mol, 1500 g / mol, 2500 g / mol to 3500 g / mol, 4000 g / mol, 8000 g / mol, or any range including any two of the foregoing values ​​as endpoints, as determined by GPC chromatography using polystyrene standards.

[0035] The organosilica sol disclosed herein may contain aryl groups, such as phenyl groups. The aryl groups may be present in amounts of 1 wt%, 2 wt%, 3 wt% to 4 wt%, 5 wt%, 6 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 1 wt% to 6 wt%, 2 wt% to 5 wt%, or 3 wt% to 4 wt%, wherein the weight percentages are based on the total solid weight of the organosilica sol.

[0036] Organosilica sols may contain alkyl groups, such as methyl groups. Organosilica sols may contain aryl to alkyl groups in a molar ratio of 0.1, 0.3, 0.5 to 1.5, 2.5, 3, or any range containing any two of the foregoing values ​​as endpoints, such as 0.1 to 3, 0.3 to 2.5, or 0.5 to 1.5.

[0037] The organic silica sol may contain pure inorganic silanes (according to Q unit in Table 1) without carbon atoms attached to silicon groups, such as tetraethyl orthosilicate or tetramethyl orthosilicate. The organic silica sol may contain any range of organically substituted silanes to pure inorganic silanes in the form of 0, 0.05, 0.1, 0.25, 0.5, or any two of the foregoing values ​​as endpoints, such as 0 to 0.1, 0.1 to 0.25, or 0.25 to 0.5 molar ratios (according to the ratio of Q / (M+D+T) in Table 1).

[0038] The organosilica sol disclosed herein may have a solid concentration of 20 wt%, 25 wt%, 30 wt% to 40 wt%, 50 wt%, 60 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 20 wt% to 60 wt%, 25 wt% to 50 wt%, or 30 wt% to 35 wt%.

[0039] The coating composition provided in this disclosure may contain organosilica sol in weight percentages of 10 wt%, 30 wt%, 40 wt% to 60 wt%, 70 wt%, 90 wt%, or any range including any of the foregoing values ​​as endpoints, such as 10 wt% to 90 wt%, 30 wt% to 70 wt%, or 40 wt% to 60 wt%, wherein the weight percentages are based on the total weight of the “wet” coating composition.

[0040] Organic silica may be present in the cured coating composition in amounts of 10 wt%, 30 wt%, 40 wt% to 60 wt%, 70 wt%, 90 wt%, or any range including any of the foregoing values ​​as endpoints, such as 10 wt% to 90 wt%, 30 wt% to 70 wt%, or 40 wt% to 60 wt%, where the weight percentage is based on the total weight of the “dried” coating composition.

[0041] A. Siloxane monomers

[0042] As shown in Table 1 below, siloxane monomers can be described based on the degree of oxygen substitution or functionality on the central silicone.

[0043] Table 1: Types of Siloxane Monomers

[0044]

[0045] Suitable tetrafunctional siloxane monomers used in the organosilica sols of this disclosure may include tetraisopropylortosilane, tetramethylortosilane, tetramethylortosilane, tetramethoxysilane, and tetraethoxysilane.

[0046] Suitable trifunctional siloxane monomers for use in the organosilica sols of this disclosure may include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, methyltriethoxysilane, and propyltriethoxysilane.

[0047] Suitable bifunctional siloxane monomers for use in the organosilica sols of this disclosure may include dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, dimethyldiethoxysilane, diphenyldiethoxysilane, methylphenyldiethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane.

[0048] Suitable monofunctional siloxane monomers for use in the organosilica sols of this disclosure may include trimethylmethoxysilane and trimethylethoxysilane.

[0049] Organosilica sols can be formed as reaction products of two or more different siloxane monomers (such as any of the siloxane monomers listed above). Furthermore, these monomers can be selected to provide organosilica sols with any aryl and alkyl content.

[0050] The aryl group may be a phenyl group, and the alkyl group may be a methyl group. The siloxane monomer may contain 0.1, 0.3, 0.5 to 1.5, 2.5, 3, or any range containing any two of the foregoing values ​​as endpoints, such as a molar ratio of aryl to alkyl groups of 0.1 to 3, 0.3 to 2.5, or 0.5 to 1.5.

[0051] The organosilica sol may contain 30 wt%, 45 wt%, 50 wt% to 60 wt%, 65 wt%, 100 wt%, or any range containing any two of the foregoing values ​​as endpoints, such as 30 wt% to 100 wt%, 45 wt% to 65 wt%, or 50 wt% to 60 wt% by weight percentage of siloxane monomers, wherein the weight percentage is based on the total weight of the organosilica sol.

[0052] B. Colloidal silica

[0053] Organosilica sol may optionally contain colloidal silica. Colloidal silica is a suspension of silica particles in a liquid phase.

[0054] Suitable colloidal silica can comprise nanoscale silica having a volume-based average particle size or D50 of 20 nm, 30 nm, 40 nm, 50 nm to 60 nm, 70 nm, 80 nm, 100 nm, or any range including any two of the foregoing values ​​as endpoints, such as 20 nm to 100 nm, 30 nm to 80 nm, 40 nm to 70 nm, or 50 nm to 60 nm, as determined by dynamic light scattering as measured by Mie scattering and Fraunhofer diffraction techniques in accordance with ISO 13320-1 practice.

[0055] Suitable colloidal silica can also have concentrations of 20 wt%, 25 wt%, 30 wt% to 35 wt%, 40 wt%, 50 wt%, or any range including any two of the foregoing values ​​as endpoints, such as nanoscale silica concentrations of 20 wt% to 50 wt%, 25 wt% to 40 wt%, or 30 wt% to 35 wt%, where the weight percentages are based on the total weight of the colloidal silica suspension. The colloidal silica particles can also contain surface functional groups, which may include hydroxides, aluminates, chlorides, or others. The continuous phase of the colloidal silica suspension can be an organic solvent, such as isopropanol, ethanol, xylene, toluene, methanol, methyl ethyl ketone, methyl isobutyl ketone, methoxypropyl acetate, and / or water, provided that the water is removed in subsequent reaction steps.

[0056] The organosilica sol may contain colloidal silica in weight percentages of 0 wt%, 10 wt%, 20 wt% to 40 wt%, 50 wt%, 60 wt%, or any range containing any two of the foregoing values ​​as endpoints, such as 0 wt% to 60 wt%, 10 wt% to 50 wt%, or 20 wt% to 50 wt%, wherein the weight percentages are based on the total weight of the organosilica sol.

[0057] C. Catalyst

[0058] The catalyst can be used in the coating compositions of this disclosure. The catalyst can be used to increase the shelf life of the resulting catalyst-containing mixture.

[0059] Suitable catalysts can be common organic acids or bases, such as formic acid, acetic acid, maleic acid, oxalic acid, malic acid, or primary amines or ammonium hydroxide.

[0060] The organosilica sol may contain a catalyst in weight percentages of 0.1 wt%, 0.5 wt%, 1 wt% to 1.5 wt%, 2 wt%, 2.5 wt%, or any range containing any two of the foregoing values ​​as endpoints, such as 0.1 wt% to 2.5 wt%, 0.5 wt% to 2 wt%, or 1 wt% to 1.5 wt%, wherein the weight percentage is based on the total weight of the organosilica sol.

[0061] D. Hydrolysis reactants

[0062] To complete the hydrolysis step of the sol-gel reaction, a hydrolysis reactant, such as water, can be used. The molar ratio of water to alkoxy (OR') groups in the siloxane monomer can be less than 2, less than 1.5, less than 1, less than 0.5, or any other range within the foregoing values.

[0063] During the condensation step of the sol-gel reaction, water can be removed from the mixture. Water removal can be facilitated by quenching the reaction through the absorption of water onto hygroscopic salts such as Na₂SO₄, zeolites, or silica gel materials. Other suitable chemical techniques can also be used to quench the reaction, such as azeotropic distillation and Dean-Stark apparatus.

[0064] The organosilica sol may contain less than 0.1 wt%, less than 0.5 wt%, less than 1 wt%, less than 1.5 wt%, or less than 2 wt%, or 2.5 wt% of hydrolysant, wherein the weight percentage is based on the total weight of the organosilica sol.

[0065] After condensation with the hydrolysing agent, the organosilica sol can have a water content of less than 20% by weight, less than 15% by weight, less than 10% by weight, or less than 5% by weight, or any range using any two of the foregoing values ​​as endpoints, such as 5% by weight to 20% by weight, or 10% by weight to 15% by weight.

[0066] III. Silicone Polyester Resin

[0067] Silicone polyester resins can be used to prepare high-temperature coatings, especially baking enamels for non-stick and heat-resistant coatings of cookware, stovetops, chimneys, or mufflers.

[0068] Silicone polyester resins can be copolymers prepared by polycondensation of diols and diacids, which are grafted with alkoxy or hydroxyl functional siloxane oligomers or monomers.

[0069] Silicone polyester resins can be supplied in dry form or dissolved in solvents such as, but not limited to, methoxypropyl acetate, toluene, xylene, butyl acetate, ethyl acetate, and methyl isobutyl ketone.

[0070] The silicone polyester resin may have a dry siloxane content of less than 90 wt%, less than 70 wt%, less than 50 wt%, less than 30 wt%, less than 10 wt%, or less than 5 wt% compared to the dry polyester.

[0071] The coating composition provided in this disclosure may contain a weight percentage of silicone polyester resin in the form of 10 wt%, 30 wt%, 40 wt% to 50 wt%, 60 wt%, 70 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 10 wt% to 70 wt%, 30 wt% to 60 wt%, or 40 wt% to 50 wt%, wherein the weight percentage is based on the total weight of the “wet” coating composition.

[0072] The silicone polyester resin may be present in the cured coating composition in amounts of 10 wt%, 30 wt%, 40 wt% to 50 wt%, 80 wt%, 90 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 10 wt% to 90 wt%, 30 wt% to 80 wt%, or 40 wt% to 50 wt%, where the weight percentage is based on the total weight of the “dried” coating composition.

[0073] IV. Silicone Oil

[0074] Silicone oils can be used in coating compositions to improve non-stick and cleanability properties. The coating compositions disclosed herein may contain one or more silicone oils, such as medium molecular weight silicone oils, high molecular weight silicone oils, or combinations thereof.

[0075] Suitable silicone oils can have the following structures:

[0076]

[0077] Where R is methyl or phenyl; R1 is a hydride, hydroxide or trimethylsilyl, and n is 3 to greater than 660.

[0078] Silicone oils can have variable viscosities, depending on their molecular weight and the organic substituents present along the chain. The viscosity of silicone oils can be 50 cP, 100 cP, 200 cP to 500 cP, 1000 cP, 5000 cP, or any range including any of the aforementioned values ​​as endpoints, such as 50 cP to 5000 cP, 100 cP to 1000 cP, or 200 cP to 500 cP, wherein the viscosity is measured at 25°C using a Brinell rotational viscometer according to ASTM D2983-09.

[0079] The coating composition provided in this disclosure may contain silicone oil in weight percentages of 0.1 wt%, 0.5 wt%, 1 wt% to 10 wt%, 15 wt%, 20 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 0.1 wt% to 20 wt%, 0.5 wt% to 15 wt%, or 1 wt% to 10 wt%, wherein the weight percentage is based on the total weight of the “wetting” coating composition.

[0080] The silicone oil may be present in the cured coating composition in amounts of 1 wt%, 2 wt%, 5 wt% to 10 wt%, 20 wt%, 40 wt%, or any range including any of the foregoing values ​​as endpoints, such as 1 wt% to 40 wt%, 2 wt% to 20 wt%, or 5 wt% to 10 wt%, where the weight percentage is based on the total weight of the “dried” coating composition.

[0081] V. Additives

[0082] The coating compositions formulated in this disclosure may also include additives such as fillers, pigments, wetting agents, rheology modifiers, defoamers, conductivity enhancers, smoke suppressants, dispersants, crosslinking agents, and toughening agents.

[0083] The coating composition provided in this disclosure may contain a total additive in the weight percentage of 1 wt%, 2 wt%, 5 wt% to 10 wt%, 15 wt%, 20 wt%, or any range including any two of the foregoing values ​​as endpoints, such as 1 wt% to 20 wt%, 2 wt% to 15 wt%, or 5 wt% to 10 wt%, wherein the weight percentage is based on the total weight of the “wet” coating composition.

[0084] Some additives may be present in the cured coating composition in amounts of 1 wt%, 2 wt%, 5 wt% to 10 wt%, 20 wt%, 40 wt%, or any range including any of the aforementioned values ​​as endpoints, such as 1 wt% to 40 wt%, 2 wt% to 20 wt%, or 5 wt% to 10 wt%, where the weight percentage is based on the total weight of the “dried” coating composition.

[0085] VI. Application and curing of the coating composition

[0086] The coating composition of this application can be applied to a variety of substrates and cured. The coating composition of this application can be applied as a single layer or as multiple layers. The multiple layers of the coating composition of this application can include a primer and an outer coating.

[0087] Figure 1 An example is a substrate 10 coated with a single layer. The substrate 10 coated with a single layer includes a substrate 12, an optional phosphate conversion layer 14, and a coating composition 16 of the present disclosure.

[0088] Figure 2 An example is a substrate 20 coated with multiple layers. A single-layer coated substrate 20 includes a substrate 12, an optional phosphate conversion layer 14, a base coat composition 26, and an outer coat composition 28. The outer and base coat compositions may comprise coating composition formulations disclosed herein.

[0089] A. Substrate

[0090] The coating composition can be applied to the surface of a substrate / article. Suitable substrates can include metals, ceramic materials, plastics, composites, and minerals. Suitable metals can include carbon steel, stainless steel, aluminum, and aluminized steel. Suitable ceramic materials can include glass, such as borosilicate glass, porcelain enamel, various fired clays, and other refractory materials. Suitable plastics and composites can include high-melting-point plastics and composites, such as plastics with melting points higher than the curing temperature of the coating formulation, including polyester, polypropylene, ABS, polyethylene, carbon fiber epoxy composites, and glass fiber epoxy composites. Suitable minerals can include mica, basalt, alumina, silica and wollastonite, marble, and granite.

[0091] B. Substrate Pretreatment

[0092] The coating composition can be applied to the surface after a pretreatment process. Suitable pretreatment processes include, but are not limited to, degreasing, acid or alkali washing, forming a surface conversion layer with phosphate, brushing, sandblasting, or shot peening.

[0093] like Figures 1 to 2As shown, suitable substrates for coating with the coating compositions of this disclosure can also be pretreated with an optional phosphate conversion layer. The phosphate conversion layer can be a coating on the substrate that produces a layer of iron phosphate, zinc phosphate, or manganese phosphate to increase corrosion resistance, lubricity, and acts as a primer for the substrate surface prior to the application of the coating composition.

[0094] The coating composition 16 disclosed herein can be applied to a substrate 12 having an optional phosphate conversion layer 14 without requiring mechanical roughening steps, such as sandblasting or shot peening.

[0095] C. Coating application

[0096] Due to the stability of the organosilica sol within the coating, the coating composition disclosed herein can be applied to the substrate without preheating.

[0097] The coating composition of this disclosure can be applied as a single layer (16) to the substrate 12 (e.g., by spraying or electrostatic spraying) Figure 1 (as shown) or applied in multiple layers (26, 28) (as shown) Figure 2 (As shown). For multi-layer coatings, the primer layer 26 can be sprayed onto the substrate 12 first. Without curing the primer layer 26, the outer layer 28 can be sprayed onto the substrate 12 coated with the primer layer 26.

[0098] Spraying can involve loading a coating composition into an apparatus, whereby the coating composition is then forced through a nozzle, causing the composition to be produced as a fine aerosol spray. The spray is then directed directly at the substrate to obtain a uniform coating.

[0099] Electrostatic spraying can involve loading a coating composition into an apparatus, wherein small charges are applied to the nozzle as the coating composition is forced through a nozzle and formed into a fine aerosol spray, causing the aerosol droplets to become slightly charged. The charged fine aerosol spray can adhere to the substrate better than an uncharged spray.

[0100] D.Cure

[0101] The coating composition disclosed herein can be cured at temperatures of 100°C, 200°C, 250°C to 350°C, 400°C, 450°C, or any range including any of the foregoing values ​​as endpoints, such as 100°C to 450°C, 200°C to 400°C, or 250°C to 350°C.

[0102] VII. Properties of the Coating Composition

[0103] Compared with known coating compositions, the coating compositions disclosed herein can have improved adhesion, storage stability, gloss, hardness, and release properties.

[0104] The coating disclosed herein may also be substantially free of, substantially free of, or completely free of fluorine-containing components.

[0105] Fluorinated components may include per- and polyfluoroalkyl substances (PFAS), such as fluoropolymers, fluorinated oligomers, and / or fluorinated small molecules.

[0106] "Substantially free of fluoropolymers" means that the coating composition may contain less than 5% by weight of fluoropolymers based on the total weight of the "wet" coating composition. "Substantially free of fluoropolymers" means that the coating composition may contain less than 1% by weight of fluoropolymers based on the total weight of the "wet" coating composition. "Completely free of fluoropolymers" means that the coating composition may contain less than 0.01% by weight of fluoropolymers based on the total weight of the "wet" coating composition.

[0107] A. Adhesion

[0108] Adhesion can be tested using standard techniques such as ASTM D3359 (standard test method for measuring adhesion by tape test) or ASTM D2197-16 (standard test method for measuring adhesion of organic coatings by scratch test).

[0109] The coating compositions disclosed herein exhibit excellent adhesion and pass adhesion tests.

[0110] B. Storage stability

[0111] Storage stability can be measured using a combination of techniques, such as ASTM D869-21 (standard test method for assessing the settling of paints); viscosity measurement according to ASTM D5125-10 (standard test method for measuring the viscosity of paints and related materials by means of an ISO flow cup); and the properties of the applied coating, such as gloss retention. The storage stability of the composition can be measured at 25°C and 60% relative humidity.

[0112] The coating composition disclosed herein can exhibit recoverable sedimentation after one week of storage; viscosity change of no more than 20% after one week of storage; and gloss change of no more than 20% after one week of storage.

[0113] C. Glossiness

[0114] The gloss of a coating can be measured by comparing its specular reflectance to that of a black glass standard. This is done using an instrument that projects a beam of light onto the surface at a fixed intensity and angle, and measures the amount of reflected light at equal but opposite angles.

[0115] The coating compositions disclosed herein may have a gloss of 40 GU, 45 GU, 50 GU or 55 GU, 60 GU, 65 GU, or any range using any two of the foregoing values ​​as endpoints, such as 40 GU to 65 GU, 45 GU to 60 GU, or 50 GU to 55 GU, wherein the gloss is measured at 60°C according to ASTM D523.

[0116] D. Pencil hardness / Hot pencil hardness

[0117] Pencil hardness describes the ability of a coating on a substrate to resist scratching, damage, or planing. The test uses a pencil of known hardness, applied with constant force at a 45-degree angle to the coated surface, to determine the hardest pencil that will not scratch the coating. Pencil hardness values ​​range from 6B to 9H, with 6B being the softest and 9H the hardest.

[0118] The coating composition disclosed herein may have a pencil hardness of 5H, 7H to 8H, 9H, or any range using any two of the foregoing values ​​as endpoints, such as 5H to 9H, to 7H to 8H, wherein the pencil hardness is measured at ambient temperature, for example at 23°C, according to ASTM D 3363.

[0119] Pencil hardness can also be tested at elevated temperatures to test the hardness of the coating when it is exposed to the head. The coating compositions of this disclosure can have a pencil hardness of 3H, 5H, or 7H, 9H, or in any range using any two of the foregoing values ​​as endpoints, such as 3H to 9H, or 5H to 7H, wherein the pencil hardness is measured at elevated temperatures, such as 25°C to 200°C, according to ASTM D 3363.

[0120] E. Dry RAT test

[0121] The coating compositions disclosed herein may have reciprocating abrasion resistance of 9000, 9500, 10000, 20000 to 70000, 80000, 90000, 100000, or any range using any two of the foregoing values ​​as endpoints, such as 9000 to 100000, 9500 to 90000, 10000 to 80000, or 20000 to 70000, wherein the abrasion resistance is measured in accordance with BSI specification BS 6079 / 1988.

[0122] F. Egg release / Steak release

[0123] The release test for dried eggs can be performed according to the following procedure based on the test method developed internally by PPG Industries.

[0124] Position the food preparation area on the heat source and stabilize it at 150°C; crack the whole egg into the food preparation area and cook for 2 minutes. Then flip the cooked egg and cook for another minute. Use a spatula to assess the ease of removal and give the following rating:

[0125] 5-Excellent-No residue sticking to the center or edge of the egg. The egg is removed intact.

[0126] 4-Good-Slightly sticky at the edges of the utensils, with or without a small amount of easily removable residue.

[0127] 3-Generally-Eggs stick together at the edges and center.

[0128] 2-Poor-The egg sticks to the surface and cannot be completely removed, leaving half of it stuck to the surface.

[0129] 1 - Failure - More than half of the eggs stuck to the surface

[0130] The coating composition disclosed herein can have excellent egg-releasing properties, indicating that the coating provides a good non-stick surface for the substrate to which it is applied.

[0131] The steak test quantifies the release properties of the coating when steak or other meat is cooked on the surface of a coated substrate. It is an appropriate release test for certain markets; the EN13834 performance test results are recognized throughout the European baking equipment industry.

[0132] To test the steak release of the coating, a substrate coated with the cured coating composition was subjected to multiple steak test cycles. Each test cycle involved cooking a raw steak on the coated substrate. Once the steak was cooked, it was removed from the surface, and the substrate was cleaned using a natural sponge. The test cycles were repeated until residue or stains remained on the coated substrate after the test cycles.

[0133] Release properties are measured by assessing the presence of residual residue and the level of staining after each test cycle. The use of a natural sponge is important for maintaining consistency in results. The steak release of the coated composition can be characterized by the number of test cycles performed before residue / stains appear.

[0134] The coating composition disclosed herein can be successfully subjected to steak release cycles of 5, 10, 15, 20 to 25, 30, 35, 40, or any range using any two of the foregoing values ​​as endpoints, such as 5 to 40, 10 to 35, 15 to 30, or 20 to 30, wherein the steak test is performed in accordance with Annex D of specification EN13834 (cookware-roasting equipment for conventional household ovens).

[0135] Example

[0136] The aspects of this disclosure are further illustrated by the following examples. It will be apparent to those skilled in the art that many modifications can be made to the materials and methods without departing from the scope of this disclosure.

[0137] Example 1: Synthesis of Organosilica Sol A

[0138] Organic silica sol A can be prepared using the formulations in Table 2 as follows.

[0139] Colloidal silica, acetic acid, isopropanol, and methoxypropanol were added to the reactor in the amounts shown in Table 2 and in the following order. The mixture was stirred until it became homogeneous and slightly turbid, and the acid was carefully homogenized completely before adding the solvent.

[0140] Subsequently, under vigorous stirring and reflux, methyltrimethoxysilane, phenyltrimethoxysilane, and methoxypropyl acetate were added in the amounts shown in Table 2 and in the following order.

[0141] React the mixture under vigorous stirring and reflux for 2 to 24 hours. Extend the reaction time by heating at a moderate temperature of 40°C to 80°C for up to 48 hours or at room temperature (25°C).

[0142] To slow the reaction, the pH is adjusted to the range of 2 to 3, and water is removed from the batch by introducing a desiccant salt (such as anhydrous sodium sulfate) or by other suitable industrial methods to stop the reaction. The resulting sol is then filtered and concentrated to approximately 40% solids content.

[0143] The organosilica sol A prepared by this technique is a clear, slightly turbid liquid that can be stored at room temperature for several months. It is characterized by a molecular weight (Mw) ranging from 1,000 to 5,000 Daltons, which can be measured by convenient GPC chromatography using polystyrene standards.

[0144] Table 2: Formulation of Organosilica Sol A

[0145]

[0146] Example 2: Synthesis of organosilica sol B: Alkali catalysis

[0147] To a 1 L four-necked flask equipped with a top stirrer, condenser, N2 inlet, and thermocouple, add 145.0 g of phenyltrimethoxysilane, 195.0 g of methyltrimethoxysilane, 60.0 g of tetraethoxysilane, and 80.0 g of isopropanol. Mix the contents at room temperature, and then add 3.67 g of ammonium hydroxide (28% to 30% aqueous solution). After 15 minutes, add 58.4 g of distilled water.

[0148] The temperature of the reaction mixture is raised to 70°C and maintained for 4 to 6 hours. Excess solvent is then removed by distillation, and the sol is separated into 40 to 50% by weight solutions.

[0149] The organosilica sol B prepared by this technology is a clear liquid that can be stored at room temperature for several months. It is characterized by a molecular weight Mw of 1,000 to 5,000 Daltons, as measured by a convenient GPC chromatography method using polystyrene standards.

[0150] Example 3: Synthesis of an innovative coating composition

[0151] The inventive (Inv.) coating compositions disclosed herein are prepared according to Table 3 below.

[0152] A.Inv. Coatings 1 and 2

[0153] The organosilica sol A prepared in Example 1 was blended with silicone-modified polyester, xylene, methoxypropyl acetate, butoxyethanol and isopropanol solvents in the amounts specified in Table 3 under high-speed dispersion.

[0154] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0155] After grinding, a certain amount of silicon carbide is added by high-speed dispersion and stirring. The final composition is formed by adding silicone liquid and additives to the formulation.

[0156] The composition was prepared as described above and then sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air-mixing spraying. After spraying, the composition was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform non-stick film with a dry film thickness of 20 to 40 µm.

[0157] The weight percentage of each component in the cured Inv. coatings 1 and 2 is illustrated in Table 5.

[0158] B.Inv. Coatings 3 and 4

[0159] To form Inv. coatings 3 and 4, the base coat was formulated by blending the organosilica sol A prepared in Example 1, having the components and amounts specified in Table 3, with methoxypropyl acetate solvent. The base coat composition was finally formed by adding silicone liquid, additives, and pearlescent mica pigment.

[0160] The outer coating compositions for Inv. Coating 3 and Coating 4 are prepared by mixing the components in the amounts specified in Table 4. The entire preparation of the base coat and outer coating compositions for Inv. Coating 3 and Coating 4 is performed under high-speed dispersion.

[0161] The base coat compositions of Inv.3 and 4 were sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air mixing spraying.

[0162] Subsequently, the outer coating compositions of Inv. Coating 3 and Coating 4 were applied on top of the base coat without a drying stage. After spraying, the compositions were dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform, non-stick film with a dry film thickness of 20 to 40 µm.

[0163] The weight percentage of each component in the cured Inv. and cured Inv. coatings 3 and 4 is illustrated in Tables 5 and 6.

[0164] C.Inv. Coating 5

[0165] To form Inv. 5, the organosilica sol A prepared in Example 1, having the components and amounts specified in Table 3, is mixed with methoxypropyl acetate solvent. The final base coat composition is formed by adding silicone liquid, additives, and pearlescent mica pigments.

[0166] The outer coating composition of Inv. Coating 5 was prepared by mixing the components specified in Table 4 using the organosilica sol of Example 2. The entire preparation of the primer and outer coating compositions for Example Coating 5 was performed under high-speed dispersion.

[0167] The base coat composition of Inv. Coating 5 is sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air mixing spraying.

[0168] Subsequently, the outer coating composition of Inv. Coating 5 was applied on top of the primer without a drying stage. After spraying, the composition was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform, non-stick film with a dry film thickness of 20 to 40 µm.

[0169] The weight percentage of each component in the cured Inv. coating 5 is illustrated in Tables 5 and 6.

[0170] Table 3: Formulation of Inv. Coating Compositions (wt%)

[0171]

[0172] Table 4: Outer coating compositions (wt%) for Inv. Coating 3 and Coating 4

[0173]

[0174] Table 5: Solid weight % of cured coating

[0175]

[0176] Table 6: Solid weight % of cured outer coatings used for Inv. Coating 3 and Coating 4

[0177]

[0178] Example 4: Synthesis of Organosilica Sol C

[0179] Use the formulations in Table 7 to prepare organosilica sol.

[0180] Acetic acid, methyltrimethoxysilane, and colloidal silica were mixed together in the amounts shown in Table 7 and in the following order.

[0181] Table 7: Formulation of Organosilica Sol C

[0182]

[0183] Stir the mixture until it becomes homogeneous and slightly cloudy, carefully homogenizing the acid completely before adding the colloidal silica. Allow the mixture to react at room temperature for 2 hours.

[0184] Example 5: Comparative Coating Composition Synthesis

[0185] The comparative coating compositions were prepared according to Table 8 below.

[0186] A. Comparison of coating compositions 1

[0187] The silicone-modified polyester resin was blended with xylene, methoxypropyl acetate, butoxyethanol and isopropanol solvents in the amounts specified in Table 8 by weight % under high-speed dispersion.

[0188] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0189] After grinding, a certain amount of silicon carbide is added by high-speed dispersion and stirring. A final composition is formed by adding silicone liquid and additives.

[0190] Comparative composition 1 was prepared as described above and subsequently sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air-mixing spraying. After spraying, comparative composition 1 was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform non-stick film with a dry film thickness of 20 to 40 µm.

[0191] The weight percentage of each component in the cured comparative coating 1 is shown in Table 10.

[0192] B. Comparison of coating compositions 2

[0193] The organosilica sol A prepared in Example 1 (Table 2) was blended with xylene, methoxypropyl acetate, butoxyethanol and isopropanol solvents in the amounts specified in Table 8 under high-speed dispersion.

[0194] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0195] After grinding, a certain amount of silicon carbide is added by high-speed dispersion and stirring. The final composition is formed by adding silicone liquid and additives to the formulation.

[0196] Comparative composition 2 was prepared and subsequently sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air-mixing spraying. After spraying, comparative composition 2 was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform non-stick film with a dry film thickness of 20 to 40 µm.

[0197] The weight percentage of each component in the cured comparative coating 2 is shown in Table 10.

[0198] C. Comparison of coating compositions 3

[0199] Organic silica sol C from Example 4 (Table 7) was blended with isopropanol in the amounts specified in Table 8.

[0200] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0201] After grinding, a certain amount of silicon carbide is added by stirring and high-speed dispersion. Comparative composition 3 is finally formed by adding silicone liquid and additives.

[0202] Comparative composition 3 was prepared and subsequently sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air-mixing spraying. After spraying, the composition was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform non-stick film with a dry film thickness of 20 to 40 µm.

[0203] The weight percentage of each component in the cured comparative coating 3 is shown in Table 10.

[0204] D. Comparison of coating compositions 4

[0205] The silicone-modified polyester resin was blended with xylene, methoxypropyl acetate, butyroethanol, and isopropanol solvents in the amounts specified in Table 8 under high-speed dispersion. It was then blended with a certain amount of solvent-stabilized colloidal silica (such as Evonik Nanopol C764).

[0206] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0207] After grinding, a certain amount of silicon carbide is added by stirring and high-speed dispersion. Comparative coating composition 4 is ultimately formed by adding silicone liquid and additives to the formulation.

[0208] Comparative coating composition 4 was prepared and subsequently sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer by air-mixing spraying. After spraying, the composition was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform non-stick film with a dry film thickness of 20 to 40 µm.

[0209] The weight percentage of each component in the cured comparative coating 4 is shown in Table 10.

[0210] E. Comparison of coating compositions 5

[0211] To prepare the base coating, the silicone-modified polyester resin was blended with xylene, methoxypropyl acetate, butyroethanol and isopropanol solvents in the amounts specified in Table 8 under high-speed dispersion.

[0212] Subsequently, the composition was blended with a silicone T resin (such as Silres REN168 supplied by Wacker) having a crosslinking degree of close to 75%, which is mainly composed of methyl and phenylsiloxanes.

[0213] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0214] After grinding, a certain amount of silicon carbide is added by high-speed dispersion and stirring. A base coating is ultimately formed by adding silicone solution and additives to the formulation.

[0215] To prepare the outer coating, a second composition was prepared by blending a silicone T resin (such as Silres REN168 supplied by Wacker) with a crosslinking degree of approximately 75%, primarily composed of methyl and phenylsiloxanes, with methoxypropyl acetate solvent in the amounts specified in Table 9. The outer coating was ultimately formed by adding silicone liquid and additives, as well as pearlescent mica pigment, to the formulation. All preparations were performed under high-speed dispersion.

[0216] A base coat was sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer via air-mixing spraying. Subsequently, an outer coat was sprayed on top of the base coat without a drying stage, resulting in comparative coating composition 5. After spraying, comparative coating composition 5 was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform, non-stick film with a dry film thickness of 20 to 40 µm.

[0217] The weight percentage of each component in the cured comparative coating 5 is illustrated in Tables 10 and 11.

[0218] F. Comparison of coating compositions 6

[0219] To prepare the base coating, a silicone-modified polyester resin was blended with xylene, methoxypropyl acetate, butyroethanol, and isopropanol solvents in amounts specified in Table 8 under high-speed dispersion. The composition was then blended with a silicone T resin (such as Silres REN168 supplied by Wacker) having a crosslinking degree of approximately 75%, primarily composed of methyl and phenylsiloxanes, and a certain amount of solvent-stabilized colloidal silica (such as Evonik Nanopol C764).

[0220] A quantity of carbon black and pyrolytic silica is ground in a liquid using a basket mill filled with zirconia beads, operated at 1000 to 1500 RPM for 60 to 240 minutes within a cooling container. Conditions may vary depending on batch size and viscosity.

[0221] After grinding, a certain amount of silicon carbide is added by high-speed dispersion and stirring. A base coating is ultimately formed by adding silicone solution and additives to the formulation.

[0222] To prepare the outer coating, a second composition was prepared by blending a silicone T resin (such as Silres REN168 supplied by Wacker) with a crosslinking degree of close to 75%, which is mainly composed of methyl and phenylsiloxanes, with an amount of methoxypropyl acetate solvent specified in Table 9 and a certain amount of solvent-stabilized colloidal silica (such as Evonik Nanopol C764).

[0223] The final outer coating composition is formed by adding silicone liquid and additives, as well as pearlescent mica pigments, to the formulation. All preparations are performed under high-speed dispersion.

[0224] A base coat was sprayed onto a metal substrate made of carbon steel pretreated with a phosphate conversion layer via air-mixing spraying. Subsequently, an outer coat was sprayed on top of the base coat without a drying stage, resulting in comparative coating composition 6. After spraying, comparative coating composition 6 was dried at 100°C for 5 minutes and finally cured at 290°C for 20 minutes to produce a uniform, non-stick film with a dry film thickness of 20 to 40 µm.

[0225] The weight percentage of each component in the cured comparative coating 6 is illustrated in Tables 10 and 11.

[0226] Table 8: Comparison of coating composition formulations (wt%)

[0227]

[0228] Table 9: Outer coating compositions (wt%) used for comparative coating 5 and comparative coating 6

[0229]

[0230] Table 10: Solid weight % of cured coating

[0231]

[0232] Table 11: Solid weight % of cured outer coatings for comparative coating 5 and comparative coating 6

[0233]

[0234] Example 6: Properties of coating compositions of INV.1 to 5 and COMP.1 to 6

[0235] The inventive coating compositions 1 to 5 presented in Table 3 and the comparative coating compositions 1 to 6 presented in Table 8 were applied by spraying a dry film thickness of approximately 20 to 30 µm onto a phosphate carbon steel substrate. The applied coatings were dried at 100°C for approximately 5 minutes and then baked at 290°C for 20 minutes to cure. Examples related to the two-coating system were applied wet-on-wet, without any drying step between the two coatings. The properties of each coating composition were measured and recorded, as shown in Table 12.

[0236] Inventive coating compositions 1 and 2 demonstrate synergistic properties in combination with silicone-modified polyester, such as the organosilica sol prepared in Example 1, and a certain amount of silicone liquid. Inventive coating compositions 1 and 2 exhibit different ratios of sol to silicone polyester resin. Compared to other solutions presented as a coating system, inventive coating compositions 1 and 2 exhibit good adhesion and durability.

[0237] Comparative coating composition 1 contains silicone polyester but does not contain organosilica sol. Comparative coating composition 1 is a non-durable and non-sticky soft thermoplastic.

[0238] Comparative coating composition 2 contains an organosilica sol but does not contain silicone polyester. Comparative coating composition 2 exhibits good non-stick durability and abrasion resistance, but has limited adhesion to phosphate carbon steel substrates.

[0239] Comparative coating composition 3 contains an organosilica sol prepared by conventional methods in the absence of phenyl groups and without stabilization. Comparative coating composition 3 exhibits superior abrasion resistance and thermosetting properties. However, the adhesive properties hinder proper adhesion to phosphate carbon steel substrates, making it impossible to test for other examples prepared without sandblasting. Furthermore, comparative coating composition 3 undergoes a rapid reaction, causing the material to gel within a few days.

[0240] Comparative coating composition 4 contains a silicone polyester incorporated with silica sol, but without any organic modification thereof. Comparative coating composition 4 exhibits a dull surface unsuitable for non-stick applications, but does show increased mechanical resistance compared to comparative coating composition 2. Compared to coating compositions Examples 1 and 2 of this disclosure, comparative coating composition 4 lacks an organosilicon structure to effectively shell the silica used in its preparation.

[0241] The inventive coating compositions 3 and 4 achieve the most efficient combination by blending an organosilica sol with a silicone polyester to form a base coat (where the superior adhesion of the silicone polyester is maximized) and then adding an outer coat (where the superior thermoplastic properties of the organosilica sol are utilized). The inventive coating compositions 3 and 4 exhibit two possible ratios of the main resin.

[0242] Comparative coating composition 5 demonstrates a combination of silicone polyester resin and silicone T resin, wherein the absence of colloidal silica in the resin results in softness and reduced non-stick durability. Comp.5 exhibits significantly reduced pencil hardness compared to coating compositions Ex.1 through 4.

[0243] Comparative coating composition 6 demonstrates a cold blending combination of key components of this disclosure, such as silicone polyester, silicone T resin, and silica sol. Compared to coating compositions Ex.1 to 4, Comp.6 exhibits reduced pencil hardness.

[0244] Table 12: Properties of Coating Compositions Inv.1 to 5 and Comp.1 to 6

[0245]

[0246] Example 7: Thermomechanical properties of coating compositions

[0247] Thermomechanical properties were studied using a TMA (Thermomechanical Analysis) system, in which a coated sample was placed on a stage in a furnace with a controlled temperature ramp, and a penetration probe was applied to the coating under a constant load. The softening point of the coating, if present, was measured as the inflection point in the original linear thermal expansion curve of the sample.

[0248] from Figure 3 It is evident that the coating formulated according to comparative coating composition 1 exhibits strong thermoplastic behavior, while comparative coating composition 2 prepared using organosilica sol does not. Despite the presence of silicone polyester resin in the blend, the inventive coating composition 1 of this disclosure unexpectedly inherits the thermosetting behavior of the organosilica sol.

[0249] Example 8: Coating compositions of INV.6 to 9 and COMP.7 and scratch resistance

[0250] The inventive (Inv.) coating compositions 6 to 9, as well as comparative coating compositions 7 and 8, were prepared using the amounts shown in Table 13 below.

[0251] The ratio of organosilica sol to silicone-modified polyester was varied between coating compositions to determine which ratio produced superior scratch resistance.

[0252] A clear film with a thickness of 10 to 20 µm is produced by spraying the coating composition onto a phosphate carbon steel panel and curing it at 290°C for 20 minutes.

[0253] Table 13: Coating Composition Formulations (wt%)

[0254]

[0255] The coated panels were tested using a Nanovea PB1000 scratch test analyzer equipped with a 40N load sensor, a Rockwell indenter, and a heated stage capable of reaching 400°C. The panels underwent scratch resistance testing with a 20mm run and progressive loads of up to 10N. The breakdown load (LC2) upon coating deterioration was captured and reported in Table 14.

[0256] Surprisingly, it was observed that the combination of organic silica sol with silicone polyester gave a superior critical load than in every other combination at room temperature.

[0257] The same experiment was performed at elevated temperatures. The combination of the two components exhibited better scratch resistance at 200°C than the individual components measured separately, indicating a surprising synergistic effect.

[0258] Table 14: Scratch Resistance

[0259]

[0260] Specific examples of the invention have been described above for illustrative purposes; however, those skilled in the art will understand that various modifications can be made to the details of the invention without departing from its fundamental principles. The invention is derived from the invention as defined in the appended claims. Therefore, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Furthermore, this application is intended to cover any deviations from this disclosure within known or conventional practice in the field to which this disclosure pertains, and which fall within the limitations of the appended claims.

[0261] aspect

[0262] Aspect 1 is a method for forming a coating composition, comprising: hydrolyzing and condensing at least two different siloxane monomers with a catalyst to form an organosilica sol, said siloxane monomers having the following formula:

[0263] R x Si(OR') 4-x

[0264] Wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and

[0265] The organic silica sol is combined with the following: silicone polyester resin; and silicone oil.

[0266] Aspect 2 is the method according to aspect 1, wherein the at least two different siloxane monomers are hydrolyzed and condensed with a catalyst to form the organosilica sol, which further comprises colloidal silica.

[0267] Aspect 3 is the method according to aspect 1 or aspect 2, wherein the organosilica sol comprises an aryl group, and the molar ratio of the aryl group to the alkyl group ranges from 0.1 to 3.0.

[0268] Aspect 4 is the method according to any one of Aspects 1 to 3, wherein the organosilica sol has a molecular weight (Mw) of 1,000 to 5,000 Daltons as determined by GPC chromatography using polystyrene standards.

[0269] Aspect 5 is the method according to any one of aspects 1 to 4, wherein in the hydrolysis and condensation steps, the molar ratio of water to the alkoxy (OR') group of the siloxane monomer is less than 1.

[0270] Aspect 6 is the method according to any one of aspects 1 to 5, wherein the organic silica sol has a water content of less than 10% by weight based on the total weight of the organic silica sol.

[0271] Aspect 7 is the method according to any one of aspects 1 to 6, wherein the silicone oil has the following formula:

[0272]

[0273] Wherein: R is methyl or phenyl; R1 is hydride, hydroxide or trimethylsilyl; and n is 3 to 600.

[0274] Aspect 8 is the method according to any one of Aspects 1 to 7, wherein the silicone oil has a viscosity of 50 cP to 5,000 cP as measured by a Brookfield rotational viscometer according to ASTM D2983-09.

[0275] Aspect 9 is a method according to any one of aspects 1 to 8, wherein the siloxane monomer comprises methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane.

[0276] Aspect 10 is the method according to any one of aspects 1 to 9, wherein the coating composition comprises a fluorinated component of less than 5% by weight based on the total weight of the coating composition.

[0277] Aspect 11 is a coating composition comprising: a silicone polyester resin; a silicone oil; and an organosilica sol containing at least two different siloxane monomers and hydrolysis and condensation reaction products with a catalyst, wherein the siloxane monomers have the following formula:

[0278] R x Si(OR') 4-x

[0279] Wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and liquid medium.

[0280] Aspect 12 is the coating composition according to aspect 11, wherein the organosilica sol further comprises colloidal silica.

[0281] Aspect 13 is a coating composition according to aspect 11 or aspect 12, wherein the organosilica sol comprises aryl groups, and the molar ratio of the aryl to the alkyl group ranges from 0.1 to 3.0.

[0282] Aspect 14 is a coating composition according to any one of aspects 11 to 13, wherein the organosilica sol has a water content of less than 10% by weight based on the total weight of the organosilica sol.

[0283] Aspect 15 is a coating composition according to any one of aspects 11 to 14, wherein the coating composition comprises at least one of the following: 10 to 70% by weight of a silicone polyester resin based on the total weight of the coating composition; 0.1 to 20% by weight of a silicone oil based on the total weight of the coating composition; and 10 to 90% by weight of an organosilica sol based on the total weight of the coating composition.

[0284] Aspect 16 is a coating composition according to any one of Aspects 11 to 15, wherein the siloxane monomer comprises methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane.

[0285] Aspect 17 is a coating composition according to any one of aspects 11 to 16, wherein the silicone oil has the following formula:

[0286]

[0287] Wherein: R is methyl or phenyl; R1 is hydride, hydroxide or trimethylsilyl; and n is 3 to 600.

[0288] Aspect 18 is a coating composition according to aspect 17, wherein the silicone oil has a viscosity of 50 to 5000 cP as measured by a Brookfield rotational viscometer according to ASTM D2983-09.

[0289] Aspect 19 is a coating composition according to any one of aspects 11 to 18, wherein the coating composition comprises a fluorinated component of less than 5% by weight based on the total weight of the coating composition.

[0290] Aspect 20 is a coating composition according to any one of Aspects 11 to 19, wherein the coating composition has a storage stability of 3 to 5 months as determined by ASTM D869-21.

[0291] Aspect 21 is an article comprising a coating comprising a cured composition of a coating composition according to any one of aspects 11 to 20.

[0292] Aspect 22 is the article according to aspect 21, wherein the curing composition comprises at least one of the following: 10 to 70% by weight of a silicone polyester resin based on the total weight of the coating composition; 1 to 40% by weight of a silicone oil based on the total weight of the coating composition; and 10 to 90% by weight of an organosilica sol based on the total weight of the coating composition.

[0293] Aspect 23 is an article according to aspect 21 or aspect 22, wherein the coating composition has at least one of the following: a pencil hardness of 5H to 9H at 23°C according to ASTM D 3363; and a pencil hardness of 3H to 9H at 25°C to 200°C according to ASTM D 3363.

[0294] Aspect 24 discloses a method for coating an article with a coating composition, comprising: applying a coating composition comprising an organosilica sol, a silicone polyester resin, and a silicone oil onto a substrate, wherein the organosilica sol comprises at least two different siloxane monomers as hydrolysis and condensation reaction products with a catalyst, the siloxane monomers having the following formula:

[0295] R x Si(OR') 4-x

[0296] Wherein: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and the coating composition is cured at a temperature of 100°C to 450°C.

[0297] Aspect 25 is the method according to aspect 24, wherein the hydrolysis and condensation reaction products further comprise colloidal silica.

[0298] Aspect 26 is the method according to aspect 24 or aspect 25, wherein the organosilica sol comprises an aryl group, and the molar ratio of the aryl to the alkyl group ranges from 0.1 to 3.0.

[0299] Aspect 27 is the method according to any one of aspects 24 to 26, wherein the organosilica sol has a water content of less than 10% by weight based on the total weight of the organosilica sol.

[0300] Aspect 28 is a method according to any one of aspects 24 to 27, further comprising: applying an outer coating layer onto the coating composition, the outer coating layer comprising an organosilica sol and a silicone oil.

[0301] Aspect 29 is a method according to any one of aspects 24 to 28, further comprising: applying a phosphate conversion layer onto the substrate prior to applying the coating composition onto the substrate.

[0302] Aspect 30 is the method according to any one of aspects 24 to 29, wherein the coating composition comprises a fluorinated component of less than 5% by weight based on the total weight of the coating composition.

Claims

1. A method for forming a coating composition, comprising: At least two different siloxane monomers are hydrolyzed and condensed with a catalyst to form an organosilica sol, wherein the siloxane monomers have the following formula: R x Si(OR') 4-x in: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and The organic silica sol is combined with the following: Silicone polyester resin; and Silicone oil.

2. The method of claim 1, wherein the hydrolysis and condensation of the at least two different siloxane monomers with a catalyst to form the organosilica sol further comprises colloidal silica.

3. The method according to claim 1 or claim 2, wherein the organosilica sol comprises aryl groups, and the molar ratio of the aryl to the alkyl group ranges from 0.1 to 3.

0.

4. The method according to any one of claims 1 to 3, wherein the organosilica sol has a molecular weight (Mw) of 1,000 to 5,000 Daltons as determined by GPC chromatography using polystyrene standards.

5. The method according to any one of claims 1 to 4, wherein in the hydrolysis and condensation steps, the molar ratio of water to the alkoxy (OR') group of the siloxane monomer is less than 1.

6. The method according to any one of claims 1 to 5, wherein the organosilica sol has a water content of less than 10% by weight based on the total weight of the organosilica sol.

7. The method according to any one of claims 1 to 6, wherein the silicone oil has the following formula: in: R is methyl or phenyl; R1 is a hydride, hydroxide, or trimethylsilyl group; and n ranges from 3 to 600.

8. The method according to any one of claims 1 to 7, wherein the silicone oil has a viscosity of 50 cP to 5,000 cP as measured using a Brookfield rotational viscometer according to ASTM D2983-09.

9. The method according to any one of claims 1 to 8, wherein the siloxane monomer comprises methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane.

10. The method according to any one of claims 1 to 9, wherein the coating composition comprises less than 5% by weight of a fluorinated component based on the total weight of the coating composition.

11. A coating composition comprising: Silicone polyester resin; Silicone oil; An organosilica sol comprising hydrolysis and condensation reaction products of at least two different siloxane monomers with a catalyst, wherein the siloxane monomers have the following formula: R x Si(OR') 4-x in: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and Liquid medium.

12. The coating composition of claim 11, wherein the organosilica sol further comprises colloidal silica.

13. The coating composition according to claim 11 or claim 12, wherein the organosilica sol comprises an aryl group, and the molar ratio of the aryl to the alkyl group ranges from 0.1 to 3.

0.

14. The coating composition according to any one of claims 11 to 13, wherein the organosilica sol has a water content of less than 10% by weight based on the total weight of the organosilica sol.

15. The coating composition according to any one of claims 11 to 14, wherein the coating composition comprises at least one of the following: The coating composition comprises 10 to 70% by weight of silicone polyester resin. The coating composition comprises 0.1 to 20% by weight of silicone oil; and The coating composition comprises 10 to 90% by weight of an organosilica sol.

16. The coating composition according to any one of claims 11 to 15, wherein the siloxane monomer comprises methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane.

17. The coating composition according to any one of claims 11 to 16, wherein the silicone oil has the following formula: in: R is methyl or phenyl; R1 is a hydride, hydroxide, or trimethylsilyl group; and n ranges from 3 to 600.

18. The coating composition of claim 17, wherein the silicone oil has a viscosity of 50 to 5000 cP as measured using a Brookfield rotational viscometer according to ASTM D2983-09.

19. The coating composition according to any one of claims 11 to 18, wherein the coating composition comprises less than 5% by weight of a fluorinated component based on the total weight of the coating composition.

20. The coating composition according to any one of claims 11 to 19, wherein the coating composition has a storage stability of 3 to 5 months as determined by ASTM D869-21.

21. An article comprising a coating, said coating comprising a cured composition of the coating composition according to any one of claims 11 to 20.

22. The article of claim 21, wherein the cured composition comprises at least one of the following: The total weight of the coating composition is 10 to 70% by weight of silicone polyester resin; The coating composition comprises 1 to 40% by weight of silicone oil; and The coating composition comprises 10 to 90% by weight of an organosilica sol.

23. The article of claim 21 or claim 22, wherein the coating composition has at least one of the following: According to ASTM D 3363, pencil hardness ranges from 5H to 9H at 23°C; and Pencil hardness is 3H to 9H according to ASTM D 3363 at 25°C to 200°C.

24. A method of coating an article with a coating composition, comprising: A coating composition comprising an organosilica sol, a silicone polyester resin, and a silicone oil is applied to a substrate, wherein the organosilica sol comprises at least two different siloxane monomers and catalyst hydrolysis and condensation reaction products, the siloxane monomers having the following formula: R x Si(OR') 4-x in: R is a straight-chain, branched, or cyclic alkyl or aryl group having up to 10 carbon atoms; R' is a straight-chain, branched, or cyclic alkyl group having up to 5 carbon atoms; and x is 0, 1, 2, or 3; and The coating composition is cured at a temperature of 100°C to 450°C.

25. The method of claim 24, wherein the hydrolysis and condensation reaction product further comprises colloidal silica.

26. The method according to claim 24 or claim 25, wherein the organosilica sol comprises an aryl group, and the molar ratio of the aryl group to the alkyl group ranges from 0.1 to 3.

0.

27. The method according to any one of claims 24 to 26, wherein the organosilica sol has a water content of less than 10% by weight based on the total weight of the organosilica sol.

28. The method according to any one of claims 24 to 27, further comprising: An outer coating is applied to the coating composition, the outer coating comprising an organosilica sol and a silicone oil.

29. The method according to any one of claims 24 to 28, further comprising: Before applying the coating composition to the substrate, a phosphate conversion layer is applied to the substrate.

30. The method according to any one of claims 24 to 29, wherein the coating composition comprises less than 5% by weight of a fluorinated component based on the total weight of the coating composition.

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