WO2025216964A1 - Aqueous coating composition containing a hydroxyl – functional aminosiloxane ester copolymer, method for preparation thereof, and use for leather treatment - Google Patents

Abstract

An aqueous coating composition includes a hydroxyl – functional aminosiloxane ester copolymer, a polyurethane binder, a surfactant, and water. The aqueous coating composition can be prepared by mixing an aqueous emulsion comprising the hydroxyl – functional aminosiloxane ester copolymer, the surfactant and water with an aqueous polyurethane emulsion or dispersion. The aqueous coating composition is useful for leather treatment. The aqueous coating composition may optionally be combined with a crosslinker. The aqueous coating composition may be applied to a leather substrate and dried to remove water, thereby providing a coating with a low coefficient of friction on the leather substrate.

Description

AQUEOUS COATING COMPOSITION CONTAINING A HYDROXYL - FUNCTIONAL AMINOSILOXANE ESTER COPOLYMER, METHOD FOR PREPARATION THEREOF, AND USE FOR LEATHER TREATMENT

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/632,615 filed on April 11, 2024, under 35 U.S.C. §119 (e). U.S. Provisional Patent Application Serial No. 63/632,615 is hereby incorporated by reference.

FIELD

[0002] An aqueous coating composition and methods for its preparation and use for treating leather is provided. More particularly, the aqueous coating composition includes a hydroxyl - functional aminosiloxane ester copolymer and an organic binder.

INTRODUCTION

[0003] Leather is often finished with one or more coatings in order to improve its overall performance, e.g., wear resistance, flexibility, etc. Such coatings are most commonly dispersions of polyurethane. Representative examples are described in: US Patents 3930921, 6353051, 6794445, 8591999, 9200404, and 10100377; and US Patent Application Publications 20050222368 and 20100310882. Silicones are often included in the aqueous coating composition to improve one or more of haptic properties (“hand”), appearance, water repellency, abrasion resistance and breathability as described in US Patent 11518905.

Representative silicone additives are commercially available as formulated blends, dispersions, suspensions, emulsions and fluids. Commercial examples include DOWSIL™ FBL-3289 and DOWSIL™ 5-7299 Dispersion (both high molecular weight silicone systems dispersed in water), DOWSIL™ CF-7256 LF Emulsion (an aqueous silicone emulsion, which is designed to be added to water based polyurethane dispersions, including water based polyurethane leather top coatings), and XIAMETER™ OFX-0531 fluid (aminomethoxy-functional polydimethylsiloxane), all available from The Dow Chemical Company of Midland, Michigan, USA.

[0004] There continues to be a need for improved aqueous leather coating compositions that offer improved performance attributes including low coefficient of friction.

SUMMARY

[0005] An aqueous coating composition comprises (A) a hydroxyl - functional aminosiloxane ester copolymer, (B) an organic polymeric binder, (C) a surfactant, and (D) water. The aqueous coating composition may be prepared by a method comprising mixing an aqueous copolymer emulsion and an aqueous binder emulsion. The aqueous coating composition is useful for forming coatings on substrates where low coefficient of friction is desired, such as leather substrates.

DETAILED DESCRIPTION

[0006] The aqueous coating composition introduced above comprises (A) the hydroxyl - functional aminosiloxane ester copolymer, (B) the organic polymeric binder, (C) the surfactant, and (D) water. The aqueous coating composition may optionally further comprise an additional starting material, which may be selected from the group consisting of: (E) a biocide, (F) a pH modifier, (G ) a pigment, (H) a thickener, (I) a rheology modifier, (J) a matting agent or duller (e.g., silica), (K) an antifoam, (L) a water repellent additive, (M) an antiblocking additive, (N) an abrasion resistance additive, (O) an antioxidant, (P) a UV absorber, (Q) a photo-stabilizer, (R) an antistatic agent, (S) a preservative (other than the biocide described above), (T) a plasticizer, (U) a flame retardant, (V) a wetting agent (other than the surfactant described above), (W) an opacifier, (X) an extender, (Y) a plasticizer, and a combination of two or more thereof.

(A) Hydroxyl - functional Aminosiloxane Ester Copolymer

[0007] Starting material (A) in the aqueous coating composition is the hydroxyl - functional aminosiloxane ester copolymer introduced above. The hydroxyl - functional aminosiloxane ester copolymer comprises formula (Al): wherein each R¹ is an independently selected monovalent hydrocarbon group of 1 to 12 carbon atoms, each R^E is an independently selected amino-functional group of formula R³2N-R^A-, wherein each R³ is independently selected from the group consisting of H and a hydroxyl- functional group of formula , wherein R⁴ is H or OH, and R⁵ is OH or H, with the provisos that when R⁴ is H, then R⁵ is OH; and when R⁴ is OH, then R⁵ is H; and

> 10 mol % to < 95 mol % of all instances of R³, per molecule, are the hydroxyl-functional group; each R^A is an independently divalent hydrocarbon group of 1 to 12 carbon atoms; each R² is independently selected from the group consisting of hydrogen and methyl; each R^D is an independently selected divalent hydrocarbon group of 2 to 20 carbon atoms; each subscript a independently has a value such that 0 < a < 150; and subscript b has a value such that 1 < b < 100.

[0008] In the formula above, suitable monovalent hydrocarbon groups for R¹ include alkyl, alkenyl, aryl, and combinations thereof (e.g., aralkyl and aralkenyl). For example, suitable alkyl groups include methyl, ethyl, propyl (including iso-propyl and n-propyl), butyl (including isobutyl, n-butyl, sec-butyl, and tert-butyl), pentyl (including linear pentyl and/or cyclopentyl) and branched alkyl groups with 5 carbon atoms, hexyl (including linear hexyl and/or cyclohexyl) and branched alkyl groups with 6 carbon atoms), octyl (including linear octyl and/or cyclooctyl), branched alkyl groups with 8 carbon atoms), decyl (including linear decyl and/or cyclodecyl) and branched alkyl groups with 10 carbon atoms, and dodecyl (including linear dodecyl and/or cyclododecyl) and branched alkyl groups with 12 carbon atoms. Alternatively, the alkyl group for R¹ may be selected from the group consisting of methyl and ethyl, alternatively methyl. Suitable alkenyl groups for R¹ include vinyl, allyl and hexenyl; alternatively vinyl or allyl; and alternatively vinyl. Suitable aryl groups for R¹ may include cyclopentadienyl, phenyl, naphthyl, and anthracenyl. Suitable aralkyl groups for R¹ include tolyl, xylyl, benzyl, 1 -phenylethyl, and 2-phenylethyl. Alternatively, the aryl group for R¹ may be phenyl. Aralkyl groups such as benzyl, 1 -phenylethyl, and 2-phenylethyl, and aralkenyl groups such as styryl, may also be used for R¹. Alternatively, each R¹ may be selected from the group consisting of methyl and phenyl. Alternatively, each R¹ may be methyl.

[0009] Each R² is independently selected from the group consisting of hydrogen and methyl. Alternatively, each R² may be hydrogen.

[0010] Each R^D is an independently selected divalent hydrocarbon group of 2 to 20 carbon atoms, alternatively 2 to 12 carbon atoms, alternatively 3 to 12 carbon atoms, alternatively 4 to 12 carbon atoms, alternatively 4 to 10 carbon atoms, alternatively 4 to 8 carbon atoms, and alternatively 6 carbon atoms. The divalent hydrocarbon groups for R^D may be linear, branched, cyclic, or combinations thereof. Suitable divalent hydrocarbon groups for R^D include alkylene groups, arylene groups, and combinations thereof. Alternatively, each R^D may be an alkylene group such as propylene, butylene, hexylene, octylene, decylene, or dodecylene; alternatively each R^D may be butylene, hexylene, or decylene. Alternatively, R^D may be a branched alkylene group. The arylene group for R^D may be arylene group such as phenylene. Alternatively, R^D may be a dialkylarylene group such as: is independently 1 to 6, alternatively 1 to 2.

[0011] Each R^E is an independently selected amino-functional group of formula R³zN-R^A-, where R^A is a divalent hydrocarbon group. Each R^A is an independently selected divalent hydrocarbon group of 1 to 12 carbon atoms, alternatively 2 to 12 carbon atoms, alternatively 2 to 6 carbon atoms, and alternatively 2 to 3 carbon atoms. The divalent hydrocarbon groups for R^A may be linear, branched, or cyclic, or combinations thereof. Suitable divalent hydrocarbon groups for R^A include alkylene groups, arylene groups, and combinations thereof (e.g., dialkylarylene groups). The alkylene group is exemplified by ethylene, propylene, or butylene. The arylene group for R^A may be arylene group such as phenylene. Alternatively, R^A may be a dialkylarylene group such as: subscript u is as described above. Alternatively, each R^A may be an alkylene group such as ethylene, propylene, butylene, or hexylene; alternatively ethylene. Alternatively, each R^E may be a secondary amino-functional group (i.e., in each amino-functional group of formula R³rN-R^A-, one R³ is H and the other is the hydroxyl- functional group). Alternatively, each R^E may be a tertiary amino-functional group (i.e., in each amino-functional group of formula R³2N-R^A-, each R³ is the hydroxyl-functional group).

[0012] In the formula for the hydroxyl - functional aminosiloxane ester copolymer > 10 mol % to < 95 mol %, alternatively 50 mol % to 90 mol %, alternatively 55 mol % to 90 mol %, alternatively 60 mol % to 85 mol %, alternatively 65 mol % to 85 mol %, alternatively 70 mol % to 80 mol %, and alternatively 75 mol % of all instances of R³ per molecule are the hydroxyl- functional group. [0013] Subscript a has a value such that 0 < a < 150. Alternatively, subscript a may have a value of at least 14, alternatively at least 16, alternatively at least 40, alternatively at least 42, alternatively at least 44, and alternatively at least 80; while at the same time, subscript a may have a value up to 143, alternatively up to 142, alternatively up to 140, alternatively up to 100, alternatively up to 90, and alternatively up to 86. Alternatively, subscript a may have a value of 2 to < 150, alternatively 2 to 145, alternatively 2 to 143, alternatively 2 to 142, alternatively 14 to 86, alternatively 16 to 84, alternatively 14 to 143, alternatively 42 to 143, alternatively 43 to 143, alternatively 44 to 143, alternatively 80 to 143, alternatively, 84 to 140, and alternatively 80 to 86.

[0014] Subscript b has a value such that 1 < b < 100. Alternatively, subscript b may have a value of 2 to 20, and alternatively 2 to 10.

[0015] The hydroxyl - functional aminosiloxane ester copolymer described above may have a number average molecular weight (Mn) of > 769 g/mol, alternatively 769 g/mol to 250,000 g/mol, and alternatively > 1,000 g/mole to 250,000 g/mole measured by GPC according to the test method described hereinbelow. Alternatively, the hydroxyl - functional aminosiloxane ester copolymer may have a Mn of > 1,244 g/mol, alternatively 4,000 g/mole to 250,000 g/mole, alternatively 4,000 g/mole to 100,000 g/mole, measured by GPC.

[0016] Alternatively, the hydroxyl - functional aminosiloxane ester copolymer described above may have a Mw of 2,000 g/mol to 400,000 g/mol. Alternatively, Mw may be 10,000 g/mol to 390,000 g/mol; alternatively 12,000 g/mol to 200,000 g/mol; alternatively 15,000 g/mol to 185,000 g/mol; alternatively 19,000 g/mol to 175,000 g/mol; alternatively 20,000 g/mol to 100,000 g/mol; alternatively 21,000 g/mol to 80,000 g/mol; alternatively 22,000 g/mol to 75,000 g/mol; alternatively 25,000 g/mol to 65,000 g/mol; alternatively 30,000 g/mol to 60,000 g/mol; alternatively 35,000 g/mol to 55,000 g/mol; and alternatively 40,000 g/mol to 50,000 g/mol. [0017] The hydroxyl - functional aminosiloxane ester copolymer described above may be prepared by a process comprising: 1) combining, under conditions to effect reaction, starting materials comprising: (i) an aminosiloxane ester copolymer terminated with primary aminofunctional groups, (ii) glycidol, and optionally (iii) a solvent. The aminosiloxane ester copolymer terminated with primary amino-functional groups is known in the art and may be prepared, e.g., by a process comprising combining a terminal primary amino-functional polyorganosiloxane and a bis-acryloyloxy-alkane as described in PCT Patent Application Publication WO2023278918 to Rekken, et al. The aminosiloxane ester copolymer terminated with primary amino-functional groups comprises formula (il): wherein each R¹ is the independently selected monovalent hydrocarbon group of 1 to 12 carbon atoms, each R^A is the independently divalent hydrocarbon group of 1 to 12 carbon atoms, each R² is independently selected from the group consisting of hydrogen and methyl, each R^D is the independently selected divalent hydrocarbon group of 2 to 20 carbon atoms, each subscript a independently has the value such that 0 < a < 150; and subscript b has the value such that 1 < b < 100, each as described above, and each R^E is independently a group of formula H2N-R^A-, where R^A is as described above.

[0018] The process for preparing the copolymer described herein comprises: 7 ) combining starting materials comprising (i) the aminosiloxane ester copolymer with terminal primary amino-functional groups, (ii) glycidol, and optionally (iii) a solvent. Glycidol has general formula which is commercially available from various sources such as Millipore Sigma of St. Louis, Missouri, USA.

[0019] Starting material (i) the aminosiloxane ester copolymer terminated with primary aminofunctional groups, and starting material (ii) the glycidol, are added in amounts to provide a molar ratio of NH/ epoxy groups, where N-H content is calculated as moles N-H on the terminal primary amino-functional polyorganosiloxane minus the moles of acrylate functional groups on the bis-acryloyloxy-alkane used for preparing the aminosiloxane ester copolymer terminated with primary amino-functional groups (i.e., N-H/Epoxy mol ratio) >1/1, alternatively > 1/1, alternatively at least 1.05/1; alternatively at least 1.2/1; and alternatively at least 1.3/1; while at the same time N-H/Epoxy mol ratio may be up to 2/1, alternatively up to 1.5/1, and alternatively up to 1.3/1. The reactants may be heated at a temperature of at least 40 °C, alternatively 50 °C to 100 °C, alternatively 60 °C to 70 °C.

[0020] Alternatively, the starting materials may be mixed and/or heated during step ). The method may optionally further comprise adding starting material (iii), a solvent. The solvent may optionally be added, e.g., with mixing and before heating, to facilitate mixing of (i) the aminosiloxane ester copolymer terminated with primary amino-functional groups and (ii) the glycidol. The process may further comprise mixing the aminosiloxane ester copolymer and/or the glycidol with (iii) the solvent, e.g., for a time sufficient to dissolve the aminosiloxane ester copolymer terminated with primary amino-functional groups and/or the glycidol in the solvent before heating. The solvent may be a monohydric alcohol, e.g., methanol, ethanol, propanol including isopropanol, and/or butanol; or a polyhydric alcohol such as diethylene glycol butyl ether (butyl carbitol). Optionally, a co-solvent may be used with the solvent. The co-solvent may comprise isododecane (IDD), dipropylene glycol dimethyl ether, or a combination thereof. The method may optionally further comprise: 2/ recovering the hydroxyl - functional aminosiloxane ester copolymer prepared herein, by any convenient means, such as stripping and/or distillation to remove unreacted starting materials, side products, and/or solvent, when used.

[0021] The hydroxyl - functional aminosiloxane ester copolymer may be provided in an aqueous copolymer emulsion. Said emulsion may comprise: (I) a liquid continuous phase comprising water, and (II) a discontinuous phase dispersed in the liquid continuous phase, where the discontinuous phase comprises the hydroxyl - functional aminosiloxane ester copolymer described above. The amount of the hydroxyl - functional aminosiloxane ester copolymer added to the aqueous copolymer emulsion can vary and is not limited. However, the amount typically may range from a weight ratio of copolymer/emulsion of 1 to 70%, alternatively 2 to 60%. Water (and additional starting materials, if present) may constitute the balance of the aqueous copolymer emulsion to 100%.

Water

[0022] The water is not generally limited, and may be utilized neat (i.e., absent any carrier vehicles/sol vents), and/or pure (i.e., free from or substantially free from minerals and/or other impurities). For example, the water may be processed or unprocessed prior to making the aqueous copolymer emulsion described herein. Examples of processes that may be used for purifying the water include distilling, filtering, deionizing, and combinations of two or more thereof, such that the water may be deionized, distilled, and/or filtered. Alternatively, the water may be unprocessed (e.g. may be tap water, i.e., provided by a municipal water system or well water, used without further purification). Alternatively, the water may be purified before use to make the aqueous copolymer emulsion. The water is used in addition to the hydroxyl-functional aminosiloxane ester copolymer (and additional starting materials, if any) to a balance of 100 % of the aqueous copolymer emulsion.

Additional Starting Materials

[0023] The aqueous copolymer emulsion described above may further comprise an additional starting material selected from the group consisting of a surfactant, an acid compound, an acid anhydride, a thickener, a stabilizer, a preservative, and a combination of two or more thereof. [0024] The hydroxyl - functional aminosiloxane ester copolymer described above may be self-emulsifying (i.e., a separate surfactant is optional). However, when used, the surfactant may be anionic, cationic, nonionic, or amphoteric, or a combination of two or more thereof. The amount of surfactant may be 2 % to 25%, alternatively 2% to 20%, based on combined weights of all starting materials in the aqueous copolymer emulsion.

Surfactant

[0025] The aqueous copolymer emulsion comprising (A) the hydroxyl - functional aminosiloxane ester copolymer may further comprise a surfactant. The surfactant may be anionic, cationic, nonionic, amphoteric, or a combination thereof. The anionic surfactant may selected from alkali metal sulfosuccinates, sulfonated glyceryl esters of fatty acids, salts of sulfonated monovalent alcohol esters, amides of amino sulfonic acids, sulfonated products of fatty acids nitriles, sulfonated aromatic hydrocarbons, condensation products of naphthalene sulfonic acids with formaldehyde, sodium octahydroanthracene sulfonate, sodium lauryl sulfate, alkali metal alkyl sulfates, alkyl ether sulfates having at least 8 carbon atoms, alkyl aryl ether sulfates, alkylarylsulfonates having at least 8 carbon atoms, alkylbenzenesulfonic acids, salts of alkylbenzenesulfonic acids, sulfuric esters of polyoxyethylene alkyl ether, amine salts or sodium salts or potassium salts of alkylnaphthylsulfonic acid, and combinations thereof. Suitable anionic surfactants are commercially available from various sources including sodium lauryl sulfate, which is available from Pilot under the tradename CALIMULSE™ SLS. Other anionic surfactants commercially available from The Dow Chemical Company, include alkyldiphenyloxide disulfonate salts, which are available under the tradename DOWFAX™; dioctyl sulfosuccinates, which are available under the tradename TRITON™ GR; phosphate esters, which are available under the tradename TRITON™ H-55, H-65, QS-44, OR XQS-20; sulfates and sulfonates, which are available under the tradename TRITON™ QS-15 and TRITON™ XN-45S.

[0026] The cationic surfactant may be selected from dodecylamine acetate, octadecylamine acetate, acetates of the amines of tallow fatty acids, homologues of aromatic amines having fatty acids, fatty amides derived from aliphatic diamines, fatty amides derived from aliphatic diamines, fatty amides derived from disubstituted amines, derivatives of ethylene diamine, quaternary ammonium compounds, salts of quaternary ammonium compounds, alkyl trimethylammonium hydroxides, dialkyldimethylammonium hydroxides, coconut oil, methylpolyoxyethylene cocoammonium chloride, dipalmitoylethyl hydroxyethylammonium methosulfate, amide derivatives of amino alcohols, amine salts of long chain fatty acids, and combinations thereof. Cationic surfactants are commercially available from various sources including dialkylmethyl quaternary ammonium compounds (e.g., cetrimonium chloride) under the tradename ARQUAD™ from Akzo Nobel; ADOGEN™ cationic surfactants from Evonik; TOMAH™ cationic surfactants from Tomah Products, Inc. of Milton, Wisconsin, USA; and VARIQUAT™ cationic surfactants from Sea-Land Chemical Company of Westlake, Ohio, USA.

[0027] The nonionic surfactant may be selected from alkylphenol alkoxylates, ethoxylated and propoxylated fatty alcohols, alkyl polyglucosides and hydroxyalky] polyglucosides, sorbitan derivatives, N- alkylglucamides, alkylene oxide block copolymers, such as block copolymers of ethylene oxide, propylene oxide and/or butylene oxide, fatty alcohol polyglycolethers, polyhydroxy and polyalkoxy fatty acid derivatives, amine oxides, silicone polyethers, various polymeric surfactants. Nonionic surfactants are commercially available, for example, alkylphenol alkoxylates are available under the tradename ECOSURF™ EH; secondary alcohol ethoxylates, nonylphenol ethoxylates, and ethylene oxide/propylene oxide copolymers are commercially available under the tradename TERGITOL™; and specialty alkoxylates such as amine ethoxylates and octylphenol ethoxylates are available under the tradename TRITON ™, all from The Dow Chemical Company. Alternatively, the nonionic surfactant may be, e.g., trideceth-6 or trideceth-12, which are available under the tradename SYNPERONIC™ from Croda or LUTENSOL™ from BASF. Alternatively, the nonionic surfactant may be e.g., a fatty alcohol polyglycol ether such as GENAPOL™ UD 050, and GENAPOL™ UDI 10, which are commercially available from Clariant of Frankfurt, Germany.

[0028] Alternatively, the nonionic surfactant may comprise, or may be, a silicone polyether (SPE). The silicone polyether as an emulsifier may have a rake type structure wherein the polyoxyethylene or polyoxyethylene-polyoxypropylene copolymeric units are grafted onto the siloxane backbone, or the SPE can have an ABA block copolymeric structure wherein A represents the polyether portion and B the siloxane portion of an ABA structure. Suitable silicone polyethers include DOWSIL™ OFX-5329 Fluid from The Dow Chemical Company. Alternatively, the nonionic surfactant may be selected from polyoxyalkylene-substituted silicones, silicone alkanolamides, silicone esters and silicone glycosides. Such silicone-based surfactants are known in the art, and have been described, for example, in U.S. Patent 4,122,029 to Gee et al., U.S. Patent 5,387,417 to Rentsch, and U.S. Patent 5,811,487 to Schulz et al.

[0029] Suitable amphoteric surfactants include betaines such as alkyl(C12-14)betaine, cocoamidopropylbetaine, cocoamidopropyldimethyl-hydroxysulphobetaine, dodecylbetaine, hexadecylbetaine, and tetradecylbetaine; sultaines such as cocamidopropylhydroxysultaine; lecithin; hydrogenated lecithin; cocoamphodiacetates; cocoiminodipropionate; and dodecyliminodipropionate.

[0030] Alternatively, the surfactant in the aqueous copolymer emulsion may be a nonionic surfactant. Alternatively, the surfactant may be an organic surfactant. Alternatively, the surfactant may be both organic and nonionic.

[0031] The aqueous copolymer emulsion may be formed as a water-in-oil emulsion (w/o), which contains a water-in-oil surfactant, (which may subsequently inverted by addition of more water). The water-in-oil surfactant may be nonionic and may be selected from polyoxyalkylenesubstituted silicones, silicone alkanolamides, silicone esters and silicone glycosides, as described above. Alternatively, when the aqueous copolymer emulsion is an oil-in-water (o/w) emulsion, it may include nonionic surfactants known in the art to prepare o/w emulsions. Suitable nonionic surfactants for this embodiment are exemplified by the polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene lauryl ethers, polyoxyethylene sorbitan monooleates, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters, polyethylene glycol, polypropylene glycol, diethylene glycol, ethoxylated trimethylnonanols, and polyoxyalkylene glycol modified polysiloxane surfactants, as described above.

Acid Compound

[0032] The acid compound may optionally be added to the aqueous copolymer emulsion for adjusting pH. Suitable acids include acetic acid, formic acid, propionic acid, and combinations thereof. Suitable acids for adjusting pH are disclosed, for example, in US Patent 6180117 to Berthiaume et al.

[0033] The solvent used in the emulsion, when present, may be a solvent as described above used in the method of making the hydroxyl - functional aminosiloxane ester copolymer. The solvent may be present in the emulsion due to its presence with the hydroxyl - functional aminosiloxane ester copolymer during manufacture of said copolymer. Alternatively, the solvent may be added to the emulsion (after formation of the hydroxyl - functional aminosiloxane ester copolymer). Alternatively, the solvent in the emulsion may comprise butyl carbitol. The amount of solvent in the emulsion may be up to 10%, alternatively 1% to 5%, alternatively up to 3% based on combined weights of all starting materials in the aqueous copolymer emulsion. The solvent may be selected (type and amount) so that it does not detrimentally impact stability of the emulsion.

Method for Making the Aqueous Copolymer Emulsion

[0034] Emulsions may be prepared in a batch, semi-continuous, or continuous process using conventional equipment. For example, mixing the starting materials to form the emulsion may occur, for example using, batch equipment with high-shear and high-speed dispersers include those made by Charles Ross & Sons (NY), Hockmeyer Equipment Corp. (NJ); batch mixing equipment such as those sold under the tradename Speedmixer™; batch equipment with high shear actions include Banbury-type (CW Brabender Instruments Inc., NJ) and Henschel type (Henschel mixers America, TX). Illustrative examples of continuous mixers/compounders include extruders, such as single-screw, twin-screw, and multi-screw extruders, co-rotating extruders, such as those manufactured by Krupp Werner & Pfleiderer Corp (Ramsey, NJ), and Leistritz (NJ); twin-screw counterrotating extruders, two-stage extruders, twin-rotor continuous mixers, dynamic or static mixers or combinations of these equipment.

[0035] The starting materials described above may be combined under any suitable conditions for forming an emulsion. For example, to simplify the mixing process and keep the emulsion viscosity low while handling, any acid compound may be added at the end of the method, i.e., once the desired dilution level is reached.

[0036] The aqueous copolymer emulsion may be used in an amount sufficient to provide 0.1% to 50%, alternatively 0.1% to 10%, alternatively 0.5% to 10%, alternatively 0.5% to 10%, alternatively 1% to 5%, alternatively 0.1% to 4%, alternatively 0.1% to 3%, alternatively 0.25% to 2.75%, alternatively 0.25% to 2.5%, alternatively 0.5% to 2%, alternatively 0.5% to 1.5%, alternatively 0.75% to 1.25%, and alternatively 1%, of (A) the hydroxyl - functional aminosiloxane ester copolymer based on combined weights of all the starting materials in the aqueous coating composition described herein.

(B) Organic Polymeric Binder

[0037] Starting material (B) in the aqueous coating composition described herein is a polymeric binder (dry polymer). The polymeric binder may be (Bl) a polyurethane or (B2) an acrylic polymer. The polyurethane may be delivered in an aqueous dispersion. The aqueous polyurethane dispersion used herein to prepare the aqueous coating composition can be an externally stabilized polyurethane dispersion or an internally stabilized polyurethane dispersion. “Internally stabilized polyurethane dispersion” herein refers to a polyurethane dispersion that is stabilized through the incorporation of ionically or nonionically hydrophilic pendant groups within the polyurethane particles dispersed in the liquid medium. Examples of nonionic internally stabilized polyurethane dispersions are described in US Patents 3905929 and 3920598. Ionic internally stabilized polyurethane dispersions are known and are described in US Patent 6231926. Typically, dihydroxyalkylcarboxylic acids such as described in US Patent 3412054 are used to make anionic internally stabilized polyurethane dispersions. A common monomer used to make an anionic internally stabilized polyurethane dispersion is dimethylolpropionic acid (DMPA).

[0038] The polyurethane may be prepared by polymerization of monomers selected from polyisocyanates having 2 or more isocyanate functionalities and having 4 to 40 carbon atoms, polyols such as diols, monomers bearing at least one isocyanate group or at least one isocyanate reactive group and which in addition bear at least one hydrophilic group or potentially hydrophilic group, and optionally one or more compounds having reactive groups comprising alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups.

[0039] Suitable polyisocyanates include conventional aliphatic, cycloaliphatic, araliphatic and aromatic isocyanates. The polyisocyanate may be selected from the group of diphenylmethane diisocyanates (“MDI”), polymeric diphenylmethane diisocyanates (“pMDI”), toluene diisocyanates (“TDI”), hexamethylene diisocyanates (“HDI”), dicyclohexylmethane diisocyanates (“HMDI”), isophorone diisocyanates (“IPDI”), cyclohexyl diisocyanates (“CHDI”), naphthalene diisocyanate (“NDI”), phenyl diisocyanate (“PDI”), tetramethylene diisocyanate (“TMDI”), and combinations thereof. The polyisocyanate may have formula OCN — R — NCO, wherein R is an alkyl moiety, an aryl moiety, or an arylalkyl moiety. Alternatively, the polyisocyanate can include any number of carbon atoms described above, alternatively from 4 to 20 carbon atoms.

[0040] Specific examples of suitable poly isocyanates include: alkylene diisocyanates with 4 to 12 carbons in the alkylene radical such as 1,12-dodecane diisocyanate, 2-ethyl-l,4- tetramethylene diisocyanate, 2-methyl-l,5-pentamethylene diisocyanate, 1,4- tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as 1,3- and 1 ,4-cyclohexane diisocyanate as well as any mixtures of these isomers, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 2,4- and 2,6-hexahydrotoluene diisocyanate as well as the corresponding isomeric mixtures, 4,4'- 2,2'-, and 2,4'-dicyclohexylmethane diisocyanate as well as the corresponding isomeric mixtures, and aromatic diisocyanates and polyisocyanates such as 2,4- and 2,6-toluene diisocyanate and the corresponding isomeric mixtures, 4,4'-, 2,4'-, and 2,2'-diphenylmethane diisocyanate and the corresponding isomeric mixtures, mixtures of 4,4'-, 2,4'-, and 2,2-diphenylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates, as well as mixtures of MDI and toluene diisocyanate (TDI). Alternatively, the polyisocyanate may comprise IPDI. Alternatively, the polyurethane may be made from one or more diisocyanates, such as IPDI or TMDI and one or more polyols, such as a polyether polyol, polycarbonate polyol, or polyester polyol, e.g., having a molecular weight (Mw) of 5,000 or less, or of 2,000 or less. Such polyols may be linear and may have two hydroxyl groups, one at each end.

[0041] Suitable polyols include polyester polyols, which are reactive with the isocyanate described above include, but are not limited to, hydroxyl-functional reaction products of polyhydric alcohols, such as ethylene glycol, propylene glycol, diethylene glycol, 1,4- butanediol, neopentylglycol, 1,6-hexanediol, cyclohexane dimethanol, glycerol, trimethylolpropane, pentaerythritol, sucrose, or polyether polyols or mixtures of such polyhydric alcohols, and polycarboxylic acids, particularly dicarboxylic acids or their ester-forming derivatives, for example succinic, glutaric and adipic acids or their dimethyl esters, sebacic acid, phthalic anhydride, tetrachlorophthalic anhydride, dimethyl terephthalate or mixtures thereof. Polyester polyols obtained by the polymerization of lactones, e.g. caprolactone, in conjunction with a polyol, or of hydroxy carboxylic acids, e.g. hydroxy caproic acid, may also be used. In certain embodiments, the polyol comprises a mixture of polyester and polyether polyols. “Externally stabilized polyurethane dispersion” herein refers to a polyurethane dispersion that fails to have an ionic or nonionic hydrophilic pendant groups and thus requires the addition of a surfactant to stabilize the polyurethane dispersion. The surfactant can be those described in the copolymer emulsion above. Examples of externally stabilized polyurethane dispersions are described in US Patents 2968575, 5539021, 5688842, and 5959027.

[0042] Alternatively, the polyurethane dispersion may be an internally stabilized polyurethane dispersion. Alternatively, the polyurethane dispersion may comprise an aqueous polyurethane dispersion based on isophorone diisocyanate and polyester polyol, stabilized by carboxylate groups in the polyurethane backbone. The polyurethane may have glass transition temperature of -44 °C. Suitable polyurethane dispersions for use in preparing the aqueous coating composition are known in the art and are commercially available, for example, BAYDERM™ polyurethane dispersions such as BAYDERM™ 9fUD, which is available from The Dow Chemical Company of Midland, Michigan, USA. Alternatively, the polyurethane dispersion may be as described in US Patent 11518905 to Lenoble et al.

[0043] Other representative examples of applicable commercial polyurethane dispersion products include: PERMUTEX™ from Stahl Polymer, HAUTHANE™ L-3121 from C. L. Hauthaway & Sons Corp, and PRIMAL™ BINDER available from The Dow Chemical Company and polyurethanes from Ableridingk Boley, Inc. Other polyurethane dispersions can be prepared by methods conventional in the art. See, for example, the methods described in P. Pieterich, Aqueous Emulsion, Dispersion and Solutions of Polyurethanes; Synthesis and Properties in Progress in Organic Coatings 9 (1981) 281-340. See also: US7232859, US20040167252 and US20110112245. Such polyurethanes are commonly prepared by reacting an organic polyisocyanate with an organic compound containing isocyanate-reactive groups, particularly a polyol. The reaction may be carried out in the presence of a catalyst such as organic tin compounds and/or tertiary amines. The polyurethanes are made into aqueous dispersion by conventional means and may be anionic salt functional, non-ionic or anionic polyurethane dispersions. In one embodiment, the polyurethane dispersion may be an anionic polyurethane dispersion prepared by reacting one or more polyol with an organic compound having at least one acid group and at least two active hydrogen functionalities and a polyisocyanate. Suitable organic compounds having at least one acid group and at least two active hydrogen functionalities include, for example, 2,2-dimethylolacetic acid and 2,2- dimethylolpropionic acid. Examples of acid groups suitable for the organic compound include, carboxylic acid, sulfonic acid, phosphoric, and phosphonic acid.

[0044] Alternatively, the aqueous coating composition may comprise (B2) an acrylic polymer as (B) the polymeric binder. The acrylic polymer can be a copolymer including at least one copolymerized ethylenically unsaturated monomer and 0.4 % to 10 %, alternatively 0.4 % to 4 %, of copolymerized acetoacetate or acetoacetamide monomer, where % is relative to the total weight of monomers. Suitable ethylenically unsaturated monomers include for example a (meth)acrylic ester monomer including methyl acrylate, ethyl acrylate, butyl acrylate, 2- ethylhexyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, aminoalkyl (meth)acrylates; styrene or substituted styrenes; butadiene; vinyl acetate or other vinyl esters; vinyl monomers such as vinyl chloride, vinylidene chloride, N- vinyl pyrollidone; and acrylonitrile or methacrylonitrile. Alternatively, the copolymerized monomers may be free of functional group(s) capable of chemical reaction with acetoacetate or acetamide groups, for example, aldehyde and amine groups. Alternatively, the acrylic polymer may comprise 25% to 65% copolymerized ethyl acrylate, based on acrylic polymer weight.

[0045] The acrylic polymer useful herein may be available in the form of an aqueous emulsion. The acrylic polymer emulsion may have a solid content of 25% to 40%, or alternatively 30% to 35%. In addition to the acrylic polymer described above, the aqueous emulsion of the acrylic polymer further comprises water and a surfactant, as described above for the emulsion of the copolymer for starting material (A). Suitable commercially available acrylic polymer emulsions useful in the present invention may include, for example, HYDRHOLAC™ Cl- 1 emulsion (HYDRHOLAC is a trademark of ROHM and HAAS Company) available from The Dow Chemical Company.

[0046] The emulsion or dispersion of the polymeric binder described above may be used in an amount sufficient to provide 15% to 70%, alternatively 30% to 70%, alternatively 30 % to 60%, alternatively 30% to 40%, and alternatively 40% to 60% of (B) the polymeric binder based on combined weights of all the starting materials in the aqueous coating composition described herein.

(C) Surfactant

[0047] Starting material (C) in the aqueous coating composition is a surfactant. The surfactant may be introduced into the aqueous coating composition with starting material (A) the hydroxyl - functional aminosiloxane ester copolymer and (B) the polymeric binder, both of which may be delivered in aqueous emulsions or dispersions, as described above, and/or the surfactant may be added separately, or both. Alternatively, the surfactant in the aqueous coating composition may comprise an organic surfactant. Alternatively, the surfactant in the aqueous coating composition may be a nonionic surfactant. Alternatively, the surfactant in the aqueous coating composition may be an organic, nonionic surfactant. Said organic, nonionic surfactant may have a relatively high hydrophobic - lipophobic balance (HLB) value. For example, organic, nonionic surfactants are as described above in the emulsion for starting material (A), the aminosiloxane ester copolymer, and include those which are commercially available such as (i) 2, 6, 8 -trimethyl -4- nonyloxy polyethylene oxyethanols (6EO) and (10EO) sold under the names TERGITOL™ TMN-6 and TERGITOL™ TMN-10; (ii) the Cn-15 secondary alkyl polyoxyethylene ethers (e.g., Cn-15 secondary alcohol ethoxylates 7EO, 9EO, and 15EO sold under the names TERGITOL™ 15-S-7, TERGITOL™ 15-S-9, and TERGITOL™ 15-S-15, which has HL value 15.4), other Cn- 15 secondary alcohol ethoxylates sold under the tradenames ECOSURF™ EH-40 and TERGITOL™ 15-S-12, TERGITOL™ 15-S-3O, and TERGITOL™ 15-S-40, by the Dow Chemical Company, of Midland, Michigan, USA; octylphenyl polyoxyethylene (40) ether sold under the name TRITON™ X405 by the Dow Chemical Company; (iii) nonylphenyl polyoxyethylene (10) ether sold under the name MAKON™ 10 by the Stepan Company; (iv) ethoxylated alcohols sold under the name Trycol 5953 by Henkel Corp. /Emery Group, of Cincinnati, Ohio, USA; (v) ethoxylated alcohols sold under the name BRIJ™ L23 (with HLB value of 16.9) and BRIJ™ L4 (with HLB value of 9.7) by Croda Inc. of Edison, New Jersey, USA, (vi) polyoxyethylene 23 lauryl ether (Laureth-23) sold commercially under the trademark BRIJ™ 23; and RENEX™ 30, a polyoxyethylene ether alcohol; (vii) alkyl-oxo alcohol poly glycol ethers such as GENAPOL™ UD 050 (with HLB value of 11.4), and GENAPOL™ UD 110 (with HLB value of 14.4), (viii) alkyl polyethylene glycol ether based on ClO-Guerbet alcohol and ethylene oxide such as LUTENSOL™ XP 79, and (ix) alkyl poly glycosides, such as those sold under the trade name Glucopon™ by BASF, and alkyl glucosides such as decyl glucoside, lauryl glucoside, and coco-glucoside, which are sold under the trade name EcoSense™ by The Dow Chemical Company of Midland, Michigan, USA. Other commercially available nonionic surfactants include TERGITOL™ 15-S-5, also from The Dow Chemical Company, which has an HLB value of 10.5; LUTENSOL™ XP 50 with an HLB value of 10, LUTENSOL™ XP 79 (an alcohol ethoxylate), LUTENSOL™ XP 100 (an alcohol ethoxylate), and LUTENSOL™ XP 140 with an HLB value of 16, each of which is available from BASF. The amount of surfactant in the aqueous coating composition may be, for example, 0.03% to 25%, alternatively 0.03% to 4% based on combined weights of all the starting materials in the aqueous coating composition described herein.

(D) Water [0048] Starting material (D) in the aqueous coating composition is water. All or a portion of the water may be introduced into the aqueous coating composition with starting material (A) the hydroxyl - functional aminosiloxane ester copolymer and (B) the organic polymeric binder, both of which are typically delivered in aqueous emulsions or dispersions, as described above. The water is not specifically restricted and may be as described above in the emulsion of starting material (A) the hydroxyl - functional aminosiloxane ester copolymer. The amount of water in the aqueous coating composition is not specifically restricted. The amount of water may be > 0 to 70%, alternatively > 0 to 65%, alternatively 40% to 70%, based on combined weights of all the starting materials in the aqueous coating composition described herein.

[0049] One or more other optional additional starting materials may be included in the aqueous coating composition, as long as properties of the aqueous coating composition and performance of the coating made from the composition are not compromised. Suitable other optional starting materials include (E) a biocide, (F) a pH modifier, (G) a pigment, (H) a thickener, (I) a rheology modifier, (J) a matting agent or duller (e.g., silica), (K) an antifoam, (L) a water repellent additive, (M) an antiblocking additive, (N) an abrasion resistance additive, (O) an antioxidant, (P) a UV absorber, (Q) a photo-stabilizer, (R) an antistatic agent, (S) a preservative (other than the biocide described above), (T) a plasticizer, (U) a flame retardant, (V) a wetting agent (other than the surfactant described above), (W) an opacifier, (X) an extender, (Y) a plasticizer, and a combination of two or more thereof.

(E) Biocide

[0050] Starting material (E) is a biocide. The biocide is optional and may be added to the aqueous coating composition to ensure that the coating prepared from the aqueous coating composition provides protection against microbial attack during storage and transportation. The biocide is exemplified by a fungicide, an herbicide, a pesticide, an antimicrobial agent, or a combination thereof. Alternatively, the aqueous coating composition may comprise a fungicide, an antimicrobial agent, or a combination thereof. The amount of biocide will vary depending on factors including the type of biocide selected and the benefit desired. However, the amount of biocide may range from greater than 0 % to 5 %, alternatively from 1 ppm to 1500 ppm, each based on the weight of all starting materials in the aqueous coating composition. Biocides are known in the art and are commercially available. For example, PREVENTOL™ C40-L, which is a preservative based on p-chloro-m-cresol (PCMC); BIOBAN™ O 45 Antimicrobial;

Preventol™ BIT 20 N; Preventol™ BM 5; Preventol™ CMK 40; and Preventol™ D 7 are biocides suitable for leather treatment that are commercially available from Lanxess of Pittsburgh, Pennsylvania, USA.

(F) pH modifier [0051] Starting material (F) is a pH modifier. The pH modifier is optional and may be added to change pH of the aqueous coating composition. Without wishing to be bound by theory, it is thought that the pH modifier may be used to reduce particle size of the aqueous coating composition (which is in the form of an emulsion) as compared to a composition that does not contain the pH modifier. The pH modifier may be an acid as described above for the aqueous copolymer emulsion to deliver (A) the hydroxy] - functional aminosiloxane ester copolymer. Alternatively, the pH modifier may be a buffer such as sodium carbonate, sodium bicarbonate, and a combination thereof. The amount of the pH modifier depends on various factors such as the type of rheology modifier present, if any, however the amount of pH modifier may be 0 to 5%, alternatively > 0 to 5%, based on combined weights of all starting materials in the aqueous coating composition.

(G) Pigment

[0052] Starting material (G) is a pigment. The pigment is optional and may be added to the aqueous coating composition to impart a desired color to a coating prepared from the aqueous coating composition. Suitable pigments are known in the art and are commercially available. Pigments include carbon black and titanium dioxide. The amount of pigment may be > 0% based on based on combined weights of all the starting materials combined to prepare the aqueous coating composition described herein.

[0053] When selecting starting materials to make the aqueous coating composition described above, there may be overlap between types because certain starting materials described herein may have more than one function. For example, certain particulates may be useful as pigments and as flame retardants, e.g., carbon black. When adding additional starting materials to the aqueous coating composition, the additional starting materials are distinct from one another and from starting materials (A), (B), (C) and (D) described above. Examples of suitable optional additional starting materials and their amounts may be found for example, in US Patents 9200404, 10100377, and 11518905.

Method of Making the Aqueous Coating Composition

[0054] The aqueous coating composition may be prepared by any convenient means using any convenient equipment. The aqueous coating composition may be prepared by a method comprising:

1) mixing starting materials comprising a) an aqueous copolymer emulsion comprising

(I) a liquid continuous phase comprising water, and

(II) a discontinuous phase dispersed in the liquid continuous phase, where the discontinuous phase comprises (A) the hydroxyl - functional aminosiloxane ester copolymer, where the aqueous copolymer emulsion further comprises a surfactant, and water; b) an aqueous binder emulsion comprising (B) the organic polymeric binder and water. The method may optionally further comprise one or more additional steps before step 1), e.g., dispersing a starting material comprising a pigment in water before step 1), thereby preparing an aqueous pigment dispersion, and mixing the aqueous pigment dispersion with the starting materials in step 1). The method may optionally further comprise one or more additional steps after step 1), e.g. the method may further comprise removing agglomerated particles after step 1) and/or the method may further comprise 2) adding an additional starting material selected from starting materials (E), (F), (G), (H), (I), (J), (K), (L), (M), (N), (O), (P), (Q), (R), (S), (T), (U), (V), (W), (X), (Y), or a combination of two or more thereof, as described above. In addition, the method may optionally further comprise adding additional water for dilution, for example, for use at remote site to reduce the total solids of the aqueous coating composition to a desired range. Accordingly, the aqueous coating composition may be shipped in any stable concentrated form.

[0055] Mixing the starting materials in step 1 ) (and any optional additional steps) may be performed by any convenient means, such as mixing optionally under shear, using the equipment and methods described above for making the aqueous copolymer emulsion (described above and comprising (A) the hydroxyl - functional aminosiloxane ester copolymer). Alternatively, simple mixing may be performed to mix the starting materials in step 1), e.g., shear is not required. The aqueous coating composition prepared described above may be used to treat substrates comprising leather. Alternatively, the aqueous coating composition described above may be combined with a crosslinker and then used to treat substrates comprising leather.

Optional Crosslinker

[0056] When a crosslinker is used, the crosslinker and the aqueous coating composition are combined shortly before use (e.g., shortly before applying the aqueous coating composition to leather). For example, when a crosslinker is used, the aqueous coating composition described herein may be provided in a multiple-part system comprising a base part and a curing agent part. The base part comprises the aqueous coating composition comprising starting materials (A), (B), (C), and (D), and optionally one or more additional starting materials (E) to (Y), as described above. The curing agent part comprises the crosslinker. Suitable crosslinkers for polymeric binders such as polyurethanes are known in the art and include melamine resins, polyaziridine resins, aminoplast resins, amide- and amine-formaldehyde resins, and polyisocyanates (which may be blocked or unblocked polyisocyanates). Polyisocyanates may contain free isocyanate groups based on aliphatic, cycloaliphatic, araliphatic and/or aromatic isocyanates. The crosslinker may be water dispersible. Alternatively, the crosslinker may comprise a polyisocyanate, alternatively an aliphatic polymeric isocyanate. The crosslinking agent may be used in an amount of 0.1% or more, and up to 20%, for example, from 1% to 10%, based on combined weights of base part and curing agent part. Suitable crosslinkers are commercially available and include BINDER LS-3486-HS Crosslinker, which is supplied as a solution with viscosity < 50 cP (measured by a Brookfield LVT at 60 rpm) containing a reactive aliphatic polyisocyanate resin (50-52%); and BINDER LS-3492 Crosslinker, which is supplied as a solution with viscosity < 50 cP (measured by a Brookfield LVT at 60 rpm) containing a reactive aliphatic polyisocyanate resin (49%-51%) supplied in ethyl 3-ethoxypropionate (49%-51 %), both of which are commercially available from The Dow Chemical Company. Other commercially available crosslinkers include PZ-28 Polyfunctional Aziridine from Poly Aziridine LLC; polymeric carbodiimides from Angus Chemical Company such as Zoldine XL-29SE; such as Picassian brand or Permutex brand such as the Permutex XR 5508 from Stahl; and NeoAdd™ PAX from DSM. The system may be provided in a kit, where the kit further comprises instructions for combining the base part and the curing agent part and optionally for using the resulting crosslinkable aqueous coating composition for treating substrates comprising leather, as follows. The crosslinker is optional and may be included when desired. For example, the crosslinker may be used when the polymeric binder comprises (Bl) the polyurethane described above. Alternatively, the crosslinker may be omitted when the polymeric binder is (B2) an acrylic polymer, as described above.

Method for Treating Leather

[0057] The aqueous coating composition prepared as described above may be used to treat substrates comprising leather (i.e., natural or synthetic leather). For example, a method for treating a substrate comprises: optionally combining the base part comprising the aqueous coating composition and the curing agent part comprising the crosslinker, described above; i) applying the aqueous coating composition to a substrate comprising leather; and ii) drying the aqueous coating composition to remove water, thereby forming a coating on the substrate. When a crosslinker is used, the base part and the curing agent part may be combined by any convenient means, such as simple mixing, e.g., when the crosslinker is supplied in water. The aqueous coating composition may be applied to the substrate by any convenient method. For example, the aqueous coating composition may be applied on the substrate by a method selected from the group consisting of spraying, knife coating, roll coating, casting, drum coating, dipping, gravure coating, bar coating, screen coating, curtain coating, bmsh coating, and combinations thereof. The amount of the aqueous coating composition applied on the substrate is not specifically restricted, and may have a wet coating thickness of 10 pm to 100 pm, which may correspond to a dry coating thickness of 2 pm to 70 pm. Drying may be performed by any convenient method, such as air drying or heat drying the coated substrate. The conditions for heat drying depend on various factors including the substrate selected. For example, when the substrate comprises natural leather, the heat drying temperature may be < 120 °C. Alternatively, for synthetic leather substrates, the heat drying temperature may be < 180 °C, alternatively < 150 °C for a time sufficient to remove most or all of the water. Alternatively, the temperature may be > 100 °C to facilitate removal of the water. The method may optionally further comprise iii) repeating steps i) and ii) one or more times to increase the thickness of the coating on the substrate. The thickness of the coating to be formed on the substrate is not specifically restricted.

[0058] The aqueous coating composition and method for treating a substrate described herein may be used to provide coatings on leather, which includes both natural and synthetic leathers, such as the leather in: automotive components (e.g., on armrests, dashboards, seating, and other interior components found in vehicles); clothing such as coats, pants, flight jackets, motorcycle clothing, shoes, and gloves; luggage or handbags; accessories such as belts, wallets, and datebooks; furniture; or saddles (e.g., for bicycles or motorcycles).

EXAMPLES

[0059] The following examples are intended to illustrate the invention and are not to be construed as limiting to the scope of the invention set forth in the claims. Certain starting materials used in the Examples are described in Table 1 below, followed by characterization and evaluation procedures also used in the Examples.

Table 1 - Starting Materials

[0060] In this Reference Example 1 , hydroxyl - functional aminosiloxane ester copolymer samples were prepared as follows. A terminal primary amino-functional polyorganosiloxane (TAS) and 1 ,6-hexanediol diacrylate (HDD A) were combined at a mole ratio of 1/1 to 2/1 in the presence of a solvent. The mixture was stirred at ambient temperature for 30 minutes and then heated for a time (under temperature and time conditions shown as Heat 1 and Time 1, respectively, in Table 2, below) to give a mixture comprising an aminosiloxane ester copolymer. [0061] After heating, the mixture was allowed to cool and stir at ambient temperature overnight. Glycidol was then added at a mole ratio equal to or less than the number of moles of NH on TAS minus the number of moles of acrylate from the HDDA. The mixture was stirred at ambient temperature for 30 minutes and then heated for a time (under temperature and time conditions shown as Heat 2 and Time 2 in Table 3) to give a mixture including the dihydroxypropyl-substituted aminosiloxane ester copolymer. After the hold, the mixture was heated to 70 °C for 2 hours. Isopropyl alcohol was removed using vacuum stripping, heating to 50 °C. *H, ¹³C, and ²⁹Si NMR was used to verify the consumption of the glycidol, formation of the new dihydroxypropyl-functional aminosiloxane ester copolymer, and the removal of isopropanol. The new dihydroxypropyl-functional aminosiloxane ester copolymers made according to this procedure are summarized below in Table 2, samples la to Ih.

[0062] In this Reference Example 2, synthesis of a dihydroxypropyl-functional aminosiloxane ester copolymer was performed as follows. An aminosiloxane ester copolymer, made from the combination of an aminopropyl-terminated polydimethylsiloxane with DP = 44 and 1,6- hexanediol diacrylate at a mole ratio of 1.3/1 to 1/1 by the process described in Reference Example 1 was added to a reaction flask. Glycidol, equal to ca. 75% of the moles of NH on the aminosiloxane ester copolymer, and isopropanol, equal to 11% of the total mass, were added to the reaction flask. The mixture was stirred at ambient temperature for 30 minutes to produce a clear solution and subsequently slowly heated to 70 °C and held for 6 hours to give the dihydroxypropyl-substituted aminosiloxane ester copolymer. ¹ H, ¹³C, and ²⁹Si NMR were used to verify the consumption of the glycidol and the formation of the new dihydroxypropyl- substituted aminosiloxane ester copolymer, which is summarized below in Table 2, sample 2i. Table 2 - Preparation of AEC Copolymers according to Reference Examples 1 and 2

[0063] In Table 2, * denotes that the mixture was stirred at ambient temperature over 3 days after heating; and ** denotes that the mixture was not heated to 70 °C for two hours. The copolymers prepared as described in Reference Examples 1 and 2 were emulsified using the starting materials shown below in Table 3 and the procedure in Reference Example 3.

Table 3 - Starting Materials for Emulsions

[0064] In this Reference Example 3, the aminosiloxane ester copolymer or a hydroxyl - functional aminosiloxane ester copolymer prepared as described above were added to a speed mixer cup. Surfactant, and water in step 1 were added to the speed mixer cup and mixed at 3500 RPM for 30 seconds in a FlackTek DAC 330-100 SE SpeedMixer. At this point, a microemulsion was formed. Additional dilution water was added to the microemulsion in a stepwise manner (steps 2 and 3) with 30-second mixing at 3500 RPM in between each dilution step to lower the emulsion viscosity. Dilute acetic acid was added in step 4 to reduce the emulsion pH and further tune the emulsion clarity.

[0065] Next, aqueous coating compositions for treating leather substrates were prepared and evaluated as follows. Starting materials used in the aqueous coating compositions are shown below in Table 4.

Table 4 - Starting Materials For Aqueous Emulsions

[0066] In this Reference Example 4, aqueous coating compositions were prepared using the starting materials referenced above in Table 4, as follows: The emulsion of a hydroxyl - functional aminosiloxane ester copolymer prepared as described above was mixed with Binder 1 for 1 minute at 2700 rpm with a dental mixer. Crosslinker was added, and the resulting mixture was mixed again for w minute at 2700 rpm. The samples of aqueous coating compositions with amounts of each starting material are shown below in Table 5.

Table 5 - Aqueous Coating Compositions

[0067] Note: Comparative Example 2 (CE2) used the Comparative Silicone Emulsion in Table 4 instead of an emulsion of a hydroxyl-functional aminosiloxane ester copolymer.

[0068] In this Reference Example 5, the aqueous coating compositions in Table 5 were coated on substrates and cured, after aging at 5 days at RT plus 2 hours at 80 °C. The resulting aqueous coating compositions were applied as 2 x 34 micrometer coating on black leather and heated at 80 °C for 2 minutes. The coefficient of friction and anti-squeak performance were measured by felt (spring) against coated sample (carriage) on a Ziegler Instruments SSP-04 stick-slip tester with a normal force of F = 2.0 N and a velocity of v = 6.0 mm/s. The test was run over 10 cycles and data analysis was performed with the Ziegler Instruments software. The results are shown below in Tables 6 and 7. For leather coatings, low coefficients of friction and low values for total acceleration are desirable. Table 6 - Coefficient of Friction Results

Table 7 - Anti-squeak Performance Results

[0069] The above examples show that the working examples of this invention (IE2 to IE7) all provided better anti-squeak performance than the comparative examples (i.e., the control in comparative example 1, CE1, with no additive and with the commercially available Dowsil™ CF-7256 LF in comparative example 2, CE2). Furthermore, all working examples provided lower coefficients of friction than commercially available Dowsil™ CF-7256 LF (CE2). And, samples IE4 to IE7 had lower coefficients of friction than both comparative examples.

[0070] In this Reference Example 6, Comparative Examples 3 and 4 (CE3 and CE4) were prepared using the same method as CE1 in Reference Example 4 except that Binder 2 was used instead of Binder 1. The samples were tested as described in Reference Example 5, and the results are shown below in Tables 8 and 9. Sample IE9 was prepared using the same procedure as IE4 as described in Reference Example 4, except that Binder 2 was used instead of Binder 1. Sample IE10 was prepared using the same procedure as IE8 as described in Reference Example 4, except that Binder 2 was used instead of Binder 1. Sample IE11 was prepared the same way as sample IE9, except that the crosslinker was omitted. Sample IE12 was prepared the same way as sample IE10, except the crosslinker was omitted. Table 8 - Coefficients of Friction In Samples with Acrylic Binder and No Crosslinker

Table 9 - Coefficients of Friction In Samples with Acrylic Binder and With Crosslinker

INDUSTRIAL APPLICABILITY

[0071] Using a hydroxyl - functional aminosiloxane ester copolymer as additive at a low loading in an aqueous coating composition including a polyurethane water-based binder provided beneficial properties in the coatings prepared therewith, e.g., a combination of good anti-squeak properties and low coefficients of friction. Without wishing to be bound by theory, it is thought that using the hydroxyl - functional aminosiloxane ester copolymer may further provide one or more of the following benefits to the coating: high contact angle with water, low stick slip performance, and low leaching. To improve compatibility with the polyurethane binder, the hydroxyl - functional aminosiloxane ester copolymer may be delivered as an emulsion using a nonionic surfactant. Furthermore, the hydroxyl - functional aminosiloxane ester copolymer may provide one or more benefits over other silicone leather treatment composition active ingredients.

[0072] Without wishing to be bound by theory, it is thought that using a hydroxyl - functional aminosiloxane ester copolymer in which in formula (Al) above subscript a is at least 14, alternatively at least 42, and alternatively at least 84, alternatively up to 142, and alternatively up to 86, may provide improved static and/or dynamic coefficient of friction to a coating prepared as described herein as compared to a coating prepared from a comparative composition excluding the hydroxyl - functional aminosiloxane ester copolymer or containing a commercially available aminofunctional siloxane.

DEFINITIONS AND USAGE OF TERMS

[0073] All amounts, ratios, and percentages herein are by weight, unless otherwise indicated by the context of the specification. The articles ‘a’, ‘an’, and ‘the’ each refer to one or more, unless otherwise indicated by the context of specification. The singular includes the plural unless otherwise indicated by the context of the specification. The SUMMARY and ABSTRACT are hereby incorporated by reference. The amounts of all starting materials in a composition total 100%. The transitional phrases “comprising”, “consisting essentially of’, and “consisting of” are used as described in the Manual of Patent Examining Procedure Ninth Edition, Revision 08.2017, Last Revised January 2018 at section §2111.03 I., IL, and III. Synthetic leather is a material intended to substitute for leather where a leather-like finish is desired but the actual material is cost prohibitive or unsuitable. Synthetic leather is known under many names, including artificial leather, leatherette, imitation leather, faux leather, vegan leather, polyurethane or PU leather, and pleather. For purposes of this application, all of these are included in the substrates that can be coated with the aqueous coating composition described herein. Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. The abbreviations used herein have the definitions in Table 8.

Table 8 - Abbreviations

EMBODIMENTS OF THE INVENTION

[0074] In a first embodiment, a method for treating a substrate comprising leather, wherein the method comprises: i) applying an aqueous coating composition to a substrate comprising leather; and ii) drying the coating composition, thereby forming a coating on the leather; wherein the aqueous coating composition comprises

(A) a hydroxyl - functional aminosiloxane ester copolymer comprising formula wherein each R¹ is an independently selected monovalent hydrocarbon group of 1 to 12 carbon atoms, each R^E is an independently selected amino-functional group of formula R³2N- R^A-, wherein each R³ is independently selected from the group consisting of H and a

R⁵ hydroxyl-functional group of formula R⁴ , wherein

R⁴ is H or OH, and R⁵ is OH or H, with the provisos that when R⁴ is H, then R⁵ is OH; and when R⁴ is OH, then R⁵ is H; and per molecule, at least one with the proviso that > 10 mol % to < 95 mol % of all instances of R³ per molecule are the hydroxyl-functional group; each R^A is an independently divalent hydrocarbon group of 1 to 12 carbon atoms, each R² is independently selected from the group consisting of hydrogen and methyl, each R^D is an independently selected divalent hydrocarbon group of 2 to 20 carbon atoms, each subscript a independently has a value such that 0 < a < 150, and subscript has a value such that 1 < b < 100,

(B) an organic polymeric binder;

(C) a surfactant; and

(D) water.

[0075] In a second embodiment, in the method of the first embodiment, in the aqueous coating composition, (A) the hydroxyl - functional aminosiloxane ester copolymer has each R¹ is selected from the group consisting of methyl and phenyl; each R² is hydrogen; each R^D is propylene, butylene, hexylene, octylene, decylene, or dodecylene; each R^A is an alkylene group of 2 to 6 carbon atoms; 50 mol % to 90 mol %, of all instances of R³ per molecule are the hydroxyl-functional groups; subscript a is 80 to 140; and subscript b is 2 to 20.

[0076] In a third embodiment, in the method of the first embodiment or the second embodiment, in the aqueous coating composition, (B) the organic polymeric binder comprises a polyurethane.

[0077] In a fourth embodiment, in the method of the third embodiment, the polyurethane is based on isophorone diisocyanate and a polyester polyol, stabilized by a carboxylate group existing in the polyurethane backbone.

[0078] In a fifth embodiment, in the method of the first embodiment or the second embodiment, in the aqueous coating composition, (B) the organic polymeric binder comprises an acrylic polymer.

[0079] In a sixth embodiment, in the method of any one of the first to fifth embodiments, the aqueous coating composition further comprises an additional starting material selected from the group consisting of a biocide; a pH modifier; a pigment, a thickener, a rheology modifier, a matting agent or duller, an antifoam, a water repellent additive, an antiblocking additive, an abrasion resistance additive, an antioxidant, a UV absorber, a photo- stabilizer, an antistatic agent, a preservative, a plasticizer, a flame retardant, a wetting agent, an opacifier, an extender, a plasticizer, and a combination of two or more thereof.

[0080] In a seventh embodiment, in the method of the sixth embodiment, the aqueous coating composition further comprises: 1 ppm to 1500 ppm, by weight, based on combined weights of all starting materials in the composition, of the biocide, > 0 to 5 weight % of the pH modifier, and > 0 to 1 weight % of the rheology modifier.

[0081] In an eighth embodiment, in the method of any one of the first to seventh embodiments, the aqueous coating composition comprises: 0.1 weight% to 5 weight% of (A) the hydroxyl - functional aminosiloxane ester copolymer, 30 weight% to 70 weight% of (B) the polymeric binder, 0.03 weight % to 25 weight % of (C) the surfactant, and > 0 to 70 weight % of (D) the water.

[0082] In a ninth embodiment, the method of any one of the first to fourth embodiments further comprises adding a crosslinker to the aqueous coating composition before step i).

[0083] In a tenth embodiment, the method of any one of the first to sixth embodiments further comprises: iii) repeating steps i) and ii) one or more times to increase thickness of the coating. [0084] In an eleventh embodiment, in the method of any one of the first to tenth embodiments, the leather is selected from the group consisting of natural leather and synthetic leather.

[0085] In a twelfth embodiment, the method of any one of the first to eleventh embodiments is used to provide a coating on leather in an article selected from the group consisting of: i) an automotive component; ii) an article of clothing; iii) a piece of luggage; iv) a handbag; v) an accessory; vi) a piece of furniture; and vii) a saddle.

Claims

CLAIMS:

1. An aqueous coating composition comprises:

(A) a hydroxyl - functional aminosiloxane ester copolymer comprising formula wherein each R¹ is an independently selected monovalent hydrocarbon group of 1 to 12 carbon atoms, each R^E is an independently selected amino-functional group of formula R³IN- R^A-, wherein each R³ is independently selected from the group consisting of H and a hydroxyl-functional group of formula , wherein

R⁴ is H or OH, and

R⁵ is OH or H, with the provisos that when R⁴ is H, then R⁵ is OH; and when R⁴ is OH, then R⁵ is H; and per molecule, at least one with the proviso that > 10 mol % to < 95 mol % of all instances of R³ per molecule are the hydroxyl -functional group; each R^A is an independently divalent hydrocarbon group of 1 to 12 carbon atoms, each R² is independently selected from the group consisting of hydrogen and methyl, each R^D is an independently selected divalent hydrocarbon group of 2 to 20 carbon atoms, each subscript a independently has a value such that 0 < a < 150, and subscript has a value such that 1 < b < 100,

(B) an organic polymeric binder;

(C) a surfactant; and

(D) water.

2. The aqueous coating composition of claim 1, wherein starting material (A) has each R¹ is selected from the group consisting of methyl and phenyl; each R² is hydrogen; each R^D is propylene, butylene, hexylene, octylene, decylene, or dodecylene; each R^A is an alkylene group of 2 to 6 carbon atoms;

50 mol % to 90 mol %, of all instances of R³ per molecule are the hydroxyl-functional groups; subscript a is 80 to 140; and subscript b is 2 to 20.

3. The aqueous coating composition of claim 1 or claim 2, wherein (B) the organic polymeric binder comprises a polyurethane.

4. The aqueous coating composition of claim 3, wherein the polyurethane is based on isophorone diisocyanate and a polyester polyol, stabilized by a carboxylate group existing in the polyurethane backbone.

5. The aqueous coating composition of any one of claims 1 to 4, further comprising an additional starting material selected from the group consisting of a biocide; a pH modifier; a pigment, a thickener, a rheology modifier, a matting agent or duller, an antifoam, a water repellent additive, an antiblocking additive, an abrasion resistance additive, an antioxidant, a UV absorber, a photo-stabilizer, an antistatic agent, a preservative, a plasticizer, a flame retardant, a wetting agent, an opacifier, an extender, a plasticizer, and a combination of two or more thereof.

6. The aqueous coating composition of any one of claims 1 to 5, where the aqueous coating composition comprises:

0.1 weight% to 5 weight% of (A) the hydroxyl - functional aminosiloxane ester copolymer,

30 weight% to 70 weight% of (B) the polymeric binder, 0.03 weight % to 25 weight % of (C) the surfactant, and

> 0 to 70 weight % of (D) the water.

7. The aqueous coating composition of any one of claims 1 to 6, further comprising:

1 ppm to 1500 ppm, by weight, based on combined weights of all starting materials in the composition, of a biocide,

> 0 to 5 weight % of a pH modifier, and

> 0 to 1 weight % of a rheology modifier.

8. A crosslinkable coating composition comprising the aqueous coating composition of any one of claims 1 to 7 and a crosslinker.

9. A method for preparing the aqueous coating composition of any one of claims 1 to 7, where the method comprises:

1) mixing starting materials comprising a) an aqueous copolymer emulsion comprising

(I) a liquid continuous phase comprising water, and

(II) a discontinuous phase dispersed in the liquid continuous phase, where the discontinuous phase comprises (A) the hydroxyl - functional aminosiloxane ester copolymer, where the aqueous emulsion further comprises the surfactant, the water, the biocide, and the pH modifier; b) an aqueous binder emulsion comprising (B) the organic polymeric binder and water.

10. The method of claim 9, where the method further comprises dispersing a starting material comprising (G) a pigment in (D) water before step 1), thereby preparing an aqueous pigment dispersion, and mixing the aqueous pigment dispersion with the starting materials in step 1).

11. The method of claim 9 or claim 10, further comprising removing agglomerated particles after step 1).

12. The method of any one of claims 9 to 11, further comprising: 2) adding an additional starting material selected from the group consisting of a biocide; a pH modifier; a pigment, a thickener, a rheology modifier, a matting agent or duller, an antifoam, a water repellent additive, an antiblocking additive, an abrasion resistance additive, an antioxidant, a UV absorber, a photostabilizer, an antistatic agent, a preservative, a plasticizer, a flame retardant, a wetting agent, an opacifier, an extender, a plasticizer, and a combination of two or more thereof.

13. The method of any one of claims 9 to 12, further comprising: 3) combining the aqueous coating composition and a crosslinker.

14. A method for treating a substrate comprising leather, wherein the method comprises: i) applying the aqueous coating composition of any one of claims 1 to 7 or the crosslinkable composition of claim 8 to the leather; and ii) drying the coating composition, thereby forming a coating on the leather.

15. The method of claim 14, further comprising: iii) repeating steps i) and ii) one or more times to increase thickness of the coating.