Aqueous emulsion of ultra-high molecular weight polyorganosiloxane and methods for the preparation and use thereof

Abstract

An ultra-high molecular weight polyorganosiloxane, and an aqueous emulsion thereof, are provided. Preparation methods for the ultra-high molecular weight polyorganosiloxane and the aqueous emulsion are also provided. The aqueous emulsion of the ultra-high molecular weight polyorganosiloxane is useful as an additive in aqueous coating formulations.

Description

AQUEOUS EMULSION OF ULTRA-HIGH MOLECULAR WEIGHT POLYORGANOSILOXANE AND METHODS FOR THE PREPARATION AND USE THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 696,886 filed on 20 September 2024 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application Serial No. 63 / 696,886 is hereby incorporated by reference.FIELD

[0002] This invention relates to an emulsion with a discontinuous phase comprising an ultra- high molecular weight polyorganosiloxane dispersed in a continuous phase comprising water. This aqueous UHMW polyorganosiloxane emulsion is useful as an additive in water-based coating compositions.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] Slip additives reduce the coefficient of friction between an object and the surface of a coating made from the coating composition. A lower coefficient of friction between an object sliding over the surface of a coating desirably enable the object to slide more freely over the surface resulting in less undesirable effects such as marring and blocking (which results in squeaking as the object slides). One type of slip additive is a dispersion of a silicone gum in a carrier fluid. Such slip additives desirably are stable in aqueous coating formulations, and moredesirably are also stable in the presence of organic solvents such as coalescing aids that are often present in coating formulations. As used herein, “silicone gum” and “siloxane gum” each refer to a polyorganosiloxane, typically comprising linear chains of polydimethylsiloxane, having kinetic viscosity (r|*) of 20,000 Pa-s at 25 °C corresponding to storage modulus (G’) of 300-400 Pa measured at an angular velocity of 0.1 radian / second at 25 °C and a loss modulus (G”) of 2,000 Pa measured at an angular velocity of 0.1 radian / second at 25 °C (as shown by Crawford, et al., in “Viscosity of siloxane gum and silicone rubbers,” Asia-Pac. J. Chem. Eng. 2010; 5: 882-894, Figure 3).

[0005] “Stable” refers to an emulsion in which the dispersed (discontinuous) phase does not readily phase separate from the carrier (continuous) phase and keeps its droplet size distribution. If a slip additive is not stable in a coating formulation, phase separation occurs, causing loss of formulation homogeneity and creates coating defaults like fish-eyes, craters etc. Homogeneity is necessary for an attractive coating. Emulsions of silicone gums are useful as slip additives and anti-mar additives for both aqueous and non-aqueous coatings.

[0006] There is a movement to reduce the amount of aromatic solvents in coating formulations. Aromatic solvents such as benzene, ethyl benzene, toluene and xylene are often used in synthesizing organic and silicone compounds and are carried over to resulting coating formulations with those compounds as impurities in the coating components. During the synthesis of the organic and silicone compounds, aromatic solvents are desirable to enhance solubility of components and drive out water under a solvent reflux condition to enhance efficiency of the reaction. Aromatic solvents are also useful during drying of a coating and to induce coalescence of coating components. However, there is an industry need to reduce the use of aromatic solvents for environmental reasons. Removing aromatic solvents from slip additive compositions once they are present is not easy. Therefore, reducing the amount of aromatic solvent in a slip additive requires identifying how to form the slip additive with little or no aromatic solvent.

[0007] A slip additive that is stable in an aqueous coating formulation and in the presence of organic solvents while at the same time contains less than one weight part aromatic solvent per million weight parts slip additive would be desirable to the coating industry.SUMMARY

[0008] An aqueous ultra-high molecular weight polyorganosiloxane emulsion comprises: (A) an ultra-high molecular weight polyorganosiloxane; (B) an emulsifier comprising an ethylene oxide / propylene oxide / ethylene oxide triblock copolymer; and (C) water. A process for preparing the aqueous ultra-high molecular weight polyorganosiloxane emulsion is alsoprovided. The aqueous ultra-high molecular weight polyorganosiloxane emulsion is useful in aqueous coating compositions, which are suitable for use in treating leather.DETAILED DESCRIPTION

[0009] The aqueous ultra-high molecular weight (UHMW) polyorganosiloxane emulsion, introduced above, comprises: (A) the UHMW polyorganosiloxane having a storage modulus (G’) > 1,500 Pa and a loss modulus (G”) > 2,000 Pa measured at an angular velocity of 0.1 radian / second and 25 °C; (B) the emulsifier comprising the ethylene oxide / propylene oxide / ethylene oxide (EO-PO-EO) triblock copolymer; and (C) the water. The aqueous UHMW polyorganosiloxane emulsion may be free of filler i.e., may contain 0 to < 10 % of a filler (e.g., a metal oxide such as silica), alternatively 0 to < 1 % of a filler, and alternatively 0 to < 0.1 % of a filler. The aqueous UHMW polyorganosiloxane emulsion may be free of polyorganosiloxane resin, i.e., may contain 0 to < 10 % of a polyorganosiloxane resin, alternatively may contain 0 to < 1 % of a polyorganosiloxane resin, and alternatively 0 to < 0.1 % of a polyorganosiloxane resin. However, the aqueous UHMW polyorganosiloxane emulsion may optionally further comprise an additional starting material, as described further below.

[0010] Starting material (A) in the aqueous UHMW polyorganosiloxane emulsion is the UHMW polyorganosiloxane. The UHMW polyorganosiloxane is characterized by having a storage modulus (G’) > 1,500 Pa measured at an angular velocity of 0.1 radian / second and 25 °C according to the test method described below. Alternatively, the UHMW polyorganosiloxane may have G’ of at least 3,000 Pa, alternatively at least 5,000 Pa, alternatively at least 8,000 Pa, alternatively at least 9,000 Pa, and alternatively at least 10,000 Pa, while at the same time, G’ may be up to 50,000 Pa, alternatively up to 30,000 Pa, alternatively up to 25,000 Pa, and alternatively up to 20,000 Pa, under the same conditions. Alternatively, G’ may be 1,680 Pa to 25,214 Pa; alternatively 3,157 Pa to 25,000 Pa; alternatively 3,417 Pa to 19,524 Pa; alternatively 3,672 Pa to 16,453 Pa; alternatively 8,605 Pa to 16,362 Pa; alternatively 9,765 Pa to 16,292 Pa; alternatively 10,185 Pa to 16,147 Pa; alternatively 10,274 Pa to 14,340 Pa; and alternatively 12,090 to 13,189 Pa.

[0011] The UHMW polyorganosiloxane may have a loss modulus (G”) > 2,000 Pa measured at an angular velocity of 0.1 radian / second and 25 °C according to the test method described below. Alternatively, G” may be at least 3,000 Pa, alternatively at least 6,000 Pa, alternatively at least 7,000 Pa, alternatively at least 9,000 Pa, alternatively at least 10,000 Pa, alternatively at least 12,000 Pa, alternatively at least 15,000 Pa, and alternatively at least 17,000 Pa; while a the same time G” may be up to 20,000 Pa, alternatively up to 19,000 Pa, alternatively up to 18,000 Pa, alternatively up to 17,000 Pa, and alternatively up to 15,000 Pa, under the same conditions.Alternatively, G” may be 3,478 Pa to 18,053 Pa; alternatively 4,173 Pa to 18,035 Pa; alternatively 6,331 Pa to 16,571 Pa; alternatively 6,342 Pa to 16,147 Pa; alternatively 7,116 Pa to 13,975 Pa; alternatively 9,503 Pa to 13,965 Pa; alternatively 10,233 Pa to 12,269 Pa, and alternatively 10,274 Pa to 10,753 Pa.

[0012] The UHMW polyorganosiloxane may comprise unit formula: (R1R2R3SiOi / 2)2(R2R3SiO2 / 2)u(R2R3SiD2 / 2)v. In this unit formula, each R1is independently selected from the group consisting of H and an alkenyl group of 2 to 12 carbon atoms; and each R2and each R3are independently selected from the group consisting of alkyl groups of 1 to 12 carbon atoms and aryl groups of 6 to 12 carbon atoms. Each D is an independently selected divalent hydrocarbyl group of 2 to 12 carbon atoms. Subscripts u and v each indicate average numbers of each siloxane unit per molecule, and subscripts u and v have values sufficient to give the polyorganosiloxane the storage modulus and loss modulus described above.

[0013] Suitable alkenyl groups for R1have 2 to 12 carbon atoms and may have terminal alkenyl functionality, e.g., R1may have formula -(Cqf bqJ-CH^Cf b, wherein subscript q is 0 to 10, alternatively 0 to 6. Alternatively, each the alkenyl group may be independently selected from the group consisting of vinyl, allyl, and hexenyl. Alternatively, each R1may be independently selected from the group consisting of vinyl and allyl. Alternatively, each R1may be vinyl. Alternatively, each R1may be allyl.

[0014] Suitable alkyl groups for R2and R3are exemplified by methyl, ethyl, propyl (including n-propyl and isopropyl), butyl (including n-butyl, isobutyl, tert-butyl and sec-butyl), and linear and branched alkyl groups of 5 to 12 carbon atoms. Alternatively, the alkyl group may be selected from the group consisting of methyl, ethyl, propyl and butyl; alternatively methyl, ethyl, and propyl; alternatively methyl and ethyl. Alternatively, the alkyl group may be methyl. Suitable aryl groups for R2and R3are exemplified by monocyclic aryl groups such as phenyl, tolyl, xylyl, styryl, and benzyl; and polycyclic aryl groups such as naphthyl and anthracenyl. Alternatively, the aryl group may be monocyclic, alternatively phenyl. Alternatively, each R2may be an alkyl group, such as methyl. Alternatively, each R3may be selected from the group consisting of methyl and phenyl.

[0015] In the unit formula above, D is the divalent hydrocarbyl group of 2 to 12 carbon atoms. This divalent hydrocarbyl group forms via hydrosilylation reaction, as described below. D may be free of aliphatic unsaturation, and D may be linear or branched. Examples of divalent hydrocarbyl groups for D include alkane-diyl groups of empirical formula -CrH2r-, where subscript r is 2 to 12, alternatively 2 to 8. The alkane-diyl group may be a linear alkane-diyl, e.g., -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-CH2-CH2-, or -CH2-CH2-CH2-CH2-CH2-CH2-, or abranched alkane-diyl,. Alternatively, each D may be an alkane-diyl group of 2 to 6 carbon atoms; alternatively of 2, 3, or 6 carbon atoms.

[0016] Alternatively, (A) the ultra-high molecular weight polyorganosiloxane may have formula:and D are as described above; each R4is an alkenyl group as described above for R1; and subscripts x, y, and z have values sufficient to give the ultra-high molecular weight polyorganosiloxane the storage modulus and loss modulus described above. Alternatively, each subscript x may have an average value of 10 to 25. Alternatively, each subscript y may have an average value of 900 to 1,000. Alternatively, subscript z may be > 4,000. The UHMW polyorganosiloxane forms in situ via hydrosilylation reaction, as described further herein.

[0017] Starting material (B) in the aqueous UHMW polyorganosiloxane emulsion is the EO- PO-EO triblock copolymer. EO-PO-EO triblock copolymers are also commonly known as Poloxamers. They are non-ionic triblock copolymers composed of a central hydrophobic chain of poly oxypropylene (poly (propylene oxide)) flanked by two hydrophilic chains of polyoxyethylene (poly(ethylene oxide)). The EO-PO-EO triblock copolymer may have formula:value of 30 to 90, subscript b has an average value 25 to 75, and subscript c has an average value of 75 to 110. Alternatively, subscript a may have an average value of 39 to 82, subscript b mayhave an average value of 31 to 67, and subscript c may have an average value of 82 to 99. Alternatively, subscript a may be 34 to 44; subscript b may be 62 to 72; and subscript c may be 94 to 104. Alternatively, subscript a may be 77 to 87; subscript b may be 26 to 36; and subscript c may be 77 to 87. Suitable EO-PO-EO triblock copolymers are commercially available from various sources including Sigma- Aldrich, Inc. of St. Louis, Missouri, USA; BASF of Florham Park, New Jersey, USA; and others. For example, EO-PO-EO triblock copolymers are commercially available under the tradename PLURONIC™, such as PLURONIC™ L61, L62, L64, L81, P84F-127 and PE6800. Alternatively, starting material (B) may be selected from the group consisting of PLURONIC™ F-127 and PLURONIC™ PE6800.

[0018] Starting material (C) in the aqueous UHMW polyorganosiloxane emulsion is water. The water is not generally limited, and may be utilized neat (z.e., absent any carrier vehicles / solvents), and / or pure (z'.<?., 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 UHMW polyorganosiloxane emulsion described herein. Examples of processes that may be used for purifying the water include reverse osmosis, alternatively, 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 UHMW polyorganosiloxane emulsion. The water is used in addition to (A) the UHMW polyorganosiloxane, (B) the EO-PO-EO triblock copolymer emulsifier, and additional starting materials, if any, to a balance of 100 % of the aqueous UHMW polyorganosiloxane emulsion. For example, the aqueous UHMW polyorganosiloxane emulsion may comprise 56 weight % to 62 weight % of (A) the ultra-high molecular weight polyorganosiloxane; 2.9 weight % to 8 weight % of (B) EO-PO-EO triblock copolymer emulsifier, and a balance to 100 weight % of (C) the water.

[0019] The aqueous UHMW polyorganosiloxane emulsion has a discontinuous (internal) phase dispersed in a continuous phase. The discontinuous phase comprises (A) the ultra-high molecular weight polyorganosiloxane described above. The discontinuous phase may optionally further comprise one or more additional materials, such as an unreacted starting material, a catalyst, a plasticizer, or a combination of two or more thereof, as described below. The discontinuous phase has an average droplet size Dv50 < 8 pm measured as described in the Test Methods, below. Alternatively, discontinuous phase may have Dv50 such that 0.25 m < Dv50 < 8 pm; alternatively 0.5 pm < Dv50 < 8 pm; alternatively 1 pm < Dv50 < 8 pm; alternatively1.5 pm < Dv50 < 8 m; alternatively 2 m < Dv50 < 8 pm; and alternatively 2 pm < Dv50 < 8 pm.

[0020] Starting material (A), the UHMW polyorganosiloxane, forms in situ, e.g., via hydrosilylation reaction of starting materials comprising: (Al) a bis-alkenyl-terminated polydiorganosiloxane, and (A2) a bis-hydrido-terminated polydiorganosiloxane in the presence of (A3) a hydrosilylation reaction catalyst composition, and optionally (A4) a plasticizer. The method for making the UHMW polyorganosiloxane emulsion comprises: emulsifying, under conditions to effect hydrosilylation reaction, a reaction mixture comprising: (Al) the bis- alkenyl-terminated polydiorganosiloxane, (A2) the bis-hydrido-terminated polydiorganosiloxane, (A3) the hydrosilylation reaction catalyst composition, and the starting materials to make the emulsion further comprise (B) the emulsifier, and (C) the water; thereby forming the aqueous ultra-high molecular weight polyorganosiloxane emulsion. When present, (A4) the plasticizer may be emulsified with the other starting materials. The amounts of each starting material are sufficient to produce the UHMW polyorganosiloxane and the aqueous UHMW polyorganosiloxane emulsion.

[0021] A process for preparing the aqueous UHMW polyorganosiloxane emulsion described herein may comprise: 1) emulsifying, under conditions to effect hydrosilylation reaction, starting materials comprising 54 % to 60 %, based on combined weights of starting materials (Al), (A2), (A3) and (A4), of (Al) the bis-alkenyl-terminated polydiorganosiloxane, 1.10 % to 1.30 %, based on combined weights of starting materials (Al), (A2), (A3), and (A4) of (A2) the bis- hydrido-terminated polydiorganosiloxane, 0.5 % to 1.5 %, based on combined weights of starting materials (Al), (A2), (A3) and (A4), of (A3) the hydrosilylation reaction catalyst composition, and 0 to 5 %, based on combined weights of starting materials (Al), (A2), (A3), and (A4) of (A4) the plasticizer; (B) the emulsifier; and (C) the water; thereby preparing aqueous UHMW polyorganosiloxane emulsion comprising the ultra-high molecular weight polyorganosiloxane in the discontinuous phase. The method may further comprise mixing (Al) the bis-alkenyl-terminated polydiorganosiloxane and (A2) the bis-hydrido-terminated polydiorganosiloxane, and when present (A4) the plasticizer, before combining the resulting mixture with the other starting materials. This mixture may be combined with (B) the EO-PO- EO triblock copolymer emulsifier and a portion of (C) the water (inversion water) and mixed under shear until an emulsion forms. The particle size may be checked, and mixing under shear may be repeated until the discontinuous phase has a Dv50 < 8 pm. Thereafter, the remaining water (dilution water) may be added with mixing to dilute the aqueous emulsion to a desired concentration. Starting material (A3) the hydrosilylation reaction catalyst composition may beadded after one or more of the aliquots of water.

[0022] The aqueous UHMW polyorganosiloxane emulsion may be prepared in a batch, semi- continuous, or continuous process using conventional equipment. For example, emulsifying 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 an internal mixer (Brabender brand from Anton Paar GmbH) and Henschel type (Henschel mixers America, TX). Illustrative examples of continuous mixers / compounders include rotor-stator mixers, 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.

[0023] Starting material (Al) is the bis-alkenyl-terminated polydiorganosiloxane, which may have formula:, wherein R2, R3, R4, and subscript y are as described above. Methods of preparing linear alkenyl-functional polydiorganosiloxanes described above for starting material (Al), such as hydrolysis and condensation of the corresponding organohalosilanes and oligomers or equilibration of cyclic polydiorganosiloxanes, are known in the art, see for example US Patents 3284406; 4772515; 5169920; 5317072; and 6956087, which disclose preparing linear polydiorganosiloxanes with terminal alkenyl groups. Examples of linear polydiorganosiloxanes having terminal alkenyl groups are commercially available from various sources including, e.g., Gelest Inc. of Morrisville, Pennsylvania, USA under the tradename DMS-V.

[0024] Starting material (A2) is the bis-hydrido-terminated polydiorganosiloxane, which may have formula:, wherein R2, R3, R4, and subscript x, are as described above. Bis-hydrido-terminated polydiorganosiloxanes are also commercially available, e.g., from Sigma- Aldrich, Inc. of St. Louis, Missouri, USA. Methods of preparing bis-hydrido-terminated polydiorganosiloxanes are known in the art, see for example, US Patent 2823218 to Speier, et al. Starting materials (Al) and (A2) are added in amounts sufficient to prepare the UHMW polyorganosiloxane.

[0025] The alkenyl content of alkenyl containing siloxanes described herein, e.g., starting material (Al), may be calculated by calculating the total molecular weight of the siloxane, calculating the molecular weights of each unit containing an alkenyl group, and dividing the combined molecular weights of each unit containing an alkenyl group by the total molecular weight. For example, in the unit formula: (R2R3R4SiOi / 2)2(R2R3SiO2 / 2)(yi), when R2and R3are each methyl and R4is vinyl, and subscript y = 1000 then this unit formula represents a bis- dimethylvinylsiloxy-terminated polydimethylsiloxane ( P bDgw) with number average molecular weight (Mn) and alkenyl (vinyl) content calculated as follows:• Number average molecular weight of the copolymer is 74,762 g / mol,If Mw of MV1= 93.20 g / mol and Mw of D = 74.15 g / mol then Mn of MViD999MVi= 2*93.2 + 999*74.15 = 74,262 g / mol• The vinyl content = 0.07 %If Mw of MV1= 93.20 g / mol, Mw of D = 74. 15 g / mol, and Vinyl of Mw = 27 are, then Mn of MViD999MVi= (2*27) / (2*93.2 + 999*74.15) * 100 % = 0.0727 %

[0026] The silicon-bonded hydrogen (SiH) content of the bis-hydrido-terminated polydiorganosiloxane described herein can be determined using quantitative infra-red analysis in accordance with ASTM El 68.

[0027] The silicon-bonded hydrogen to alkenyl (e.g., vinyl) molar ratio (i.e., SiH / Vi ratio) is important when relying on a hydrosilylation reaction process. Generally, this is determined by calculating the total weight % of alkenyl groups in the starting materials to be reacted, e.g., vinyl [V] and the total weight % of silicon bonded hydrogen [H] in the starting materials to be reacted and given the molecular weight of hydrogen is 1 and of vinyl is 27 the molar ratio of silicon bonded hydrogen to vinyl is 27[H] / [V]. Amounts of starting materials (Al) and (A2), described above, may be selected so as to provide an SiH / Vi ratio of at least 0.95, alternatively > 0.95 to 1.1, alternatively 0.955 to 1.087, and alternatively 0.955 to 1.000. Alternatively, it may be desirable to have an SiH / Vi ratio < 1 to 1 to minimize unreacted silicon bonded hydrogen in the aqueous UHMW polyorganosiloxane emulsion.

[0028] Starting material (A3) comprises a hydrosilylation reaction catalyst. This catalyst will promote a reaction between the alkenyl groups in starting material (Al) and the silicon bonded hydrogen atoms in starting material (A2). Said catalyst comprises a platinum group metal. The platinum group metal may be selected from the group consisting of platinum, rhodium,ruthenium, palladium, osmium, and iridium. For example, starting material (A3) may be (A3-1) the platinum group metal, described above; (A3-2) a compound of such a metal, for example, chlorotris(triphenylphosphine)rhodium(I) (Wilkinson’s Catalyst), a rhodium diphosphine chelate such as [l,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2- bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid (Speier’s Catalyst), chloroplatinic acid hexahydrate, platinum dichloride, and (A3-3) a complex of a compound, (A3-2), with an alkenyl-functional organopolysiloxane, or (A3-4) a platinum group metal compound microencapsulated in a matrix or coreshell type structure. Complexes of platinum with low molecular weight organopolysiloxanes include 1, 3-diethenyl-l, 1,3,3- tetramethyldisiloxane complexes with platinum (Karstedt’ s Catalyst) and Pt(O) complex in tetramethyltetravinylcyclotetrasiloxane (Ashby’s Catalyst). Specific examples of suitable platinum-containing catalysts for (A3) include chloroplatinic acid, either in hexahydrate form or anhydrous form, or a platinum-containing catalyst which is obtained by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound such as divinyltetramethyldisiloxane, or alkene-platinum-silyl complexes. Alternatively, the platinum group metal may be platinum. Alternatively, to facilitate emulsification of hydrosilylation reaction catalyst with starting materials (Al) and (A2) described above, starting material (A3) may comprise an aqueous non-ionic emulsion of a hydrosilylation reaction catalyst, e.g. , an aqueous non-ionic emulsion of Karstedt’ s catalyst.

[0029] Suitable hydrosilylation reaction catalysts are known in the art and are commercially available. For example, SYL-OFF™ 4000 Catalyst is commercially available from The Dow Chemical Company of Midland, Michigan, USA.

[0030] The UHMW polyorganosiloxane prepared as described above is in the discontinuous phase of the aqueous UHMW polyorganosiloxane emulsion. Alternatively, the discontinuous phase may optionally further comprise one or more additional materials, such as an unreacted starting material, a catalyst, and / or a plasticizer, as described further, below.

[0031] Starting material (A4) is an optional plasticizer. The plasticizer is a non-reactivewherein each R5is independently selected from the group consisting of alkyl groups of 1 to 12 carbon atoms and aryl groups of 6 to 12 carbon atoms, as described above for R2and R3, and subscript w has a value sufficient to give the plasticizer a viscosity of at least 1,000,000 mPa-smeasured at 25 °C, alternatively 1,000,000 mPa- s to 10,000,000 mPa- s. Alternatively, each R5may be the alkyl group, and alternatively each Rsmay be methyl. Suitable plasticizers are exemplified by bis-trimethylsiloxy-terminated polydimethylsiloxanes with the viscosity above. Viscosity of the plasticizer may be measured at 25 °C using a Brookfield™ rotational viscometer with spindle LV-4 for viscosities over 15,000 mPa-s (Spindle LV-4 designed for viscosities in the range of 1 ,000-2,000,000 mPa- s) at an appropriate rpm. Plasticizers are known in the art and are commercially available. For example, X1AMETER™ PMX-200 Silicone Fluid with viscosity of 1,000,000 mPa-s is commercially available from The Dow Chemical Company of Midland, Michigan, USA.

[0032] The amount and selection of plasticizer depends on various factors including the G’ and G” of the UHMW polyorganosiloxane and the viscosity of the plasticizer itself, as well as the desired organic polymeric binder and other starting materials used to prepare the aqueous coating composition described below. The amount and selection of plasticizer are such that the storage modulus and the loss modulus of the discontinuous phase of the aqueous UHMW polyorganosiloxane emulsion are as described above for starting material (A), i.e., storage modulus (G’) > 1,500 Pa and loss modulus (G”) > 2,000 Pa. However, the amount of plasticizer may be 0 to 5 %, alternatively 0.5 % to 5 %, based on combined weights of starting materials (Al), (A2), (A3) and (A4).

[0033] The UHMW polyorganosiloxane described above may be used as an additive in an aqueous coating composition. The aqueous coating composition may comprise 0.5% to 10%, alternatively 1% to 5% of the UHMW polyorganosiloxane and 15 % to 99 %, alternatively 20 % to 60 %, alternatively 30 % to 40 % of an organic polymeric binder. The balance of the aqueous coating composition to 100 % comprises the EO-PO-EO triblock copolymer emulsifier and the water, and optionally an additional starting material, as described further below.

[0034] The aqueous coating composition may be prepared by a process comprising: 1) mixing starting materials comprising: (I) the aqueous ultra-high molecular weight polyorganosiloxane emulsion described above, and (II) an aqueous organic polymeric binder composition. The aqueous organic binder composition comprises (C) water (as described above) and (D) an organic polymeric binder (and optionally an emulsifier such as the EO-PO-EO triblock copolymer described herein as starting material (B) and / or a surfactant, such as the co-surfactant described herein as starting material (Z)). The aqueous coating composition may be prepared by mixing 0.1 % to 20 % of (I) the aqueous ultra-high molecular weight polyorganosiloxane emulsion and 80 % to 99.9 % of the aqueous organic polymeric binder composition.Alternatively 2% to 5% of (I) the aqueous ultra -high molecular weight polyorganosiloxaneemulsion and 95 % to 98 % of the aqueous organic polymeric binder composition. The aqueous coating composition may be prepared by any convenient means using any convenient equipment. At a commercial scale, a batch kettle with mixing means (e.g., an agitator and / or baffles). 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 UHMW polyorganosiloxane emulsion (described above). 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.

[0035] 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, as described herein. 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.

[0036] Starting material (D) in the aqueous coating composition described herein is a polymeric binder (dry polymer). The polymeric binder may be (DI) a polyurethane or (D2) 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 dimethylolpropionicacid (DMPA).

[0037] 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.

[0038] Suitable polyisocyanates include conventional aliphatic, cycloaliphatic, araliphatic and aromatic isocyanates. The polyisocyanate may be selected from the group of diphenylmethane diisocyanates (“MDI”), polymeric diphenylmethane diisocyanate (“pMDI”), toluene diisocyanate (“TDI”), hexamethylene diisocyanate (“HDI”), dicyclohexylmethane diisocyanate (“HMDI”), isophorone diisocyanate (“IPDI”), cyclohexyl diisocyanate (“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.

[0039] Specific examples of suitable polyisocyanates 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 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as 1,3- and 1 ,4-cyclohexane diisocyanate as well as any mixtures of these isomers, l-isocyanato-3,3,5- trimethyl-5-isocyanatomethylcyclohexane, 2,4- and 2, 6-hexahydro toluene 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 poly isocyanates 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 alternatively, of 2,000 or less. Such polyols may be linear and may have two hydroxyl groups, one at each end.

[0040] Suitable polyols include polyester polyols, which are reactive with the isocyanatedescribed 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. Alternatively, the polyol may comprise a mixture of polyester and polyether polyols.

[0041] “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 an EO-PO-EO triblock copolymer emulsifier described in the aqueous UHMW polyorganosiloxane emulsion above or a different surfactant exemplified by (Z) the co-surfactant described below. 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™ 91UD, 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: US Patent 7232859, US Patent Application Publication 20040167252 and US Patent Application Publication20110112245. 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. Alternatively, 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 (D2) an acrylic polymer as (D) 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 pyrrolidone; 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, which may be an EO- PO-EO triblock copolymer emulsifier as described above for starting material (B) or a different surfactant exemplified by those described below as starting material (Z). Suitable commercially available acrylic polymer emulsions useful in the present invention may include, for example, OPT-MATT™ AB-2, and HYDRHOLAC™ Cl-1 emulsion (where OPT-MATT™ &HYDRHOLAC are trademarks of ROHM and HAAS Company) available from The Dow Chemical Company.

[0046] The aqueous composition including 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 (D) the polymeric binder based on combined weights of all the starting materials in the aqueous coating composition described herein.

[0047] The aqueous UHMW polyorganosiloxane emulsion, and / or the aqueous coating composition, each as described herein, 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, (K) an antifoam, (L) a water repellent additive, (M) an antiblocking additive, (N) an abrasion resistance additive (other than the UHMW polyorganosiloxane described above), (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 coalescing solvent, (W) an opacifier, (X) an extender, (Y) a plasticizer, (Z) a co-surfactant and a combination of two or more thereof. Examples of suitable additional starting materials and their amounts are disclosed, for example, in US Patents 9200404, 10100377, and 11518905. Alternatively, the aqueous coating composition may comprise starting materials (A), (B), (C), and (D), described above, and one or both of (V) the coalescing solvent and (Z) the co-surfactant.

[0048] The coalescing solvent may optionally be used in the aqueous coating composition to facilitate formation of a coating after the aqueous coating composition is coated on a substrate, e.g., during drying. The coalescing solvent is exemplified by a monohydric alcohol (such as isopropanol), a glycol ether, a glycol ester, and a glycol ether ester. Suitable coalescing solvents are commercially available under the tradenames DOWANOL™, DALPAD™, CARBITOL™ and CELLOSOLVE™, from The Dow Chemical Company. Alternatively, the coalescing solvent may comprise butyl carbitol. The amount of coalescing solvent in the aqueous coating composition (emulsion) may be up to 10%, alternatively 1% to 5%, alternatively up to 3%, alternatively up to 1%, and alternatively up to 0.1%, based on combined weights of all starting materials in the aqueous coating composition. The coalescing solvent may be selected (type and amount) so that it does not detrimentally impact stability of the emulsion.

[0049] The non-ionic co-surfactant may optionally be included in the aqueous coating composition and / or the aqueous UHMW polyorganosiloxane emulsion. For example, a nonionic co-surfactant may be introduced when the aqueous organic polymeric binder contains asurfactant. The non-ionic co-surfactant be selected from alkylphenol alkoxylates, ethoxylated and propoxylated fatty alcohols, alkyl polyglucosides and hydroxyalkyl polyglucosides, sorbitan derivatives, N- alkylglucamides, fatty alcohol polyglycolethers, polyhydroxy and polyalkoxy fatty acid derivatives, amine oxides, silicone polyethers, and branched alcohol ethoxylates. Nonionic co-surfactants are commercially available, for example, alkylphenol alkoxylates are available under the tradename ECOSURF™ EH; secondary alcohol ethoxylates, nonylphenol ethoxylates, ethylene oxide / propylene oxide copolymers, and branched alcohol ethoxylates are commercially available under the tradename TERGITOL™, e.g., TERGITOL™ TMN-10; and specialty alkoxylates such as amine ethoxylates and octylphenol ethoxylates are available under the tradename TRITON ™, all from The Dow Chemical Company. Alternatively, the non-ionic co-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 non-ionic cosurfactant may be e.g., a fatty alcohol poly glycol ether such as GENAPOL™ UD 050, and GENAPOL™ UDI 10, which are commercially available from Clariant of Frankfurt, Germany.

[0050] Alternatively, the non-ionic co-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 non-ionic co-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 US Patent 4122029 to Gee et al., US Patent 5387417 to Rentsch, and US Patent 5811487 to Schulz et al.

[0051] Alternatively, the non-ionic co-surfactant may be exemplified by the branched secondary alcohol ethoxylates, such as TERGITOL™ TMN-10, described above. However, the non-ionic co-surfactant may be free of alkylene oxide block copolymers, such as diblock copolymers of ethylene oxide, propylene oxide and / or butylene oxide, such as EO-PO diblock copolymers. Without wishing to be bound by theory, it is thought that an alkylene oxide block copolymers, other than (B) the EO-PO-EO triblock copolymer described above, may compete with the EO-PO-EO triblock copolymer at the interface between the internal phase and the carrier, thereby rendering the aqueous UHMW polyorganosiloxane emulsion less stable than it would be without an alkylene oxide block copolymer other than starting material (B). Therefore, the aqueous UHMW polyorganosiloxane emulsion and the aqueous coating compositiondescribed herein may be free of alkylene oxide block copolymers other than starting material(B).

[0052] When selecting starting materials to make the aqueous UHMW polyorganosiloxane emulsion and the aqueous coating composition described herein, 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.

[0053] 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 (Z), 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 viscometer at 60 rpm at RT) 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 viscometer at 60 rpm at RT) 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, wherethe 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 (DI) the polyurethane described above. Alternatively, the crosslinker may be omitted when the polymeric binder is (D2) an acrylic polymer, as described above.

[0054] The aqueous coating composition prepared as described above may be used to treat substrates comprising 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, when the crosslinker is used; 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 substrate may be unfinished or basecoat finished leather. The aqueous coating composition can be applied directly onto the substrate or indirectly coated over a primer layer. The coating made from the aqueous coating composition of the present invention may include basecoats, color coats and topcoats comprising any of clear-coats, stains or translucent coatings, pigmented color coats.

[0055] 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 methods such as air-atomized spray, airassisted spray, airless spray, high volume low pressure spray, and air-assisted airless spray, knife coating, roll coating, casting, drum coating, dipping, gravure coating, bar coating, screen coating, curtain coating, brush coating, and combinations thereof. Typical application rates of the aqueous leather treatment composition are in the range of 2.0 to 100 grams dry weight per square meter (g / m2).

[0056] 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 the water. Alternatively, the temperature maybe > 100 °C to facilitate removal of the water. Alternatively, the coating composition applied to the substrate may be allowed to dry at a temperature range of 20 °C to 100 °C, alternatively 85 °C to 1000C to provide a coated leather substrate having a dried coating of the aqueous coating composition on at least one surface of the leather substrate. The drying and curing method can vary depending on, for example, the specific starting materials used to prepare the aqueous coating composition, the amount, and the type of leather. Examples of the drying method include air drying at room temperature, hot air drying at for example 85 °C, and infrared heating. 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.

[0057] The aqueous coating composition and method for treating a substrate described herein may be used to provide coatings on leather, which includes natural leathers, and leather-like substances such as artificial leathers, synthetic leathers, and vinyl leathers. Examples of the leather-like substances include polyurethanes, polyvinyl chlorides, polyolefins, and polyamides. Likewise, the aqueous coating composition described herein can be applied to natural leather that originated from, for example a cow, a sheep, a goat, a pig, a horse, a kangaroo, a deer, an alligator, or a snake. The aqueous coating composition can be applied to leather such as mineral- tanned or vegetable-tanned leather including full-grain leather, buffed or corrected-grain leather, and split leather, with or without a prior treatment with an impregnating resin mixture and with or without the application of subsequent coatings. The leather can receive a smooth or hair cell embossing prior to coating with the aqueous leather treatment composition to provide a flat surface for coating or to reduce the porosity of buffed or split leather.

[0058] The resulting coated leather article is exemplified by automotive components (e.g., 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 provided to illustrate the invention to one of ordinary skill in the art and are not to be construed so as to limit the scope of the invention in the claims. Starting materials used in these examples are summarized below in Table 1.Table 1 - Starting Materials

[0060] In this Reference Example 1, emulsion samples were made using the starting materials from Table 1 in the amounts shown below in Table 2. The Chain Extender and Vi Reactant were mixed with the dental mixer. This blend was mixed for 30 second @ 2000 rpm. Theemulsifier and a portion of the water (inversion water) were added to dental mixer. This blend was mixed for 30 second @ 3500 rpm. If necessary several passes using the dental mixer were performed to obtain inversion of emulsion and good particle size. The particle size was checked with a granulometer. When the particle size was reached, progressive dilution of the resulting thick phase emulsion was performed with additional water. The Catalyst emulsion was added at the end of the process.

[0061] Particle size, loss modulus and storage modulus were tested as described in the Test Methods, below, and the results are shown in Table 2.Table 2 - Emulsion Samples with Different Emulsifiers and with Plasticizer instead of UHMWPolyorganosiloxane

[0062] In the three emulsion samples labelled Cl, C2 and Inv 1, the internal phase and the final emulsion droplet sizes were targeted to be the same. The differences among the samples were the surfactants used. Comparative 1 (Cl) used the polyether polyol TERGITOL™ L-64 Surfactant. Comparative 2 (C2) used a mix of ethoxylated alcohols. Working example 1 (Inv 1) used an EO-PO-EO triblock copolymer, PLURONIC™ F-127. The emulsion samples C3 and Inv 2 were provided to show the impact of internal phase Mw. Comparative 3 (C3) had molecular weight, as shown by the G’ and G” values, that were far lower than the UHMW polydiorganosiloxanes prepared via hydrosilylation of the Vi Reactant and SiH Chain Extender in the internal phase of the emulsion in Inv 1.

[0063] In this Reference Example 3, the emulsion samples were evaluated for compatibility in polyurethane coating compositions. An emulsion sample as described above in an amount of 2.5weight % (1.67 g) was mixed with an amount of 97.5 weight % (20 g) of one of the PU dispersions described in Table 1, thereby forming a polyurethane coating composition. The typical wet coating thickness was fixed at 60 pm and the wet application to black Leneta card opacity form 5C (from Leneta Company, Inc. Mahwah, NJ, USA) was air dried after drawdown using 3.0 mil (76.2 pm) bird blade / drawdown bar. This was a subjective test providing a general impression about the quality of the coating. The results are expressed using Fail, Medium, or Pass. The results are shown below in Table 3.

[0064] The polyurethane coating compositions prepared as described above were used to form coatings on leather and evaluated for Abrasion resistance according to ASTM D7255- 22el Standard Test Method for Abrasion Resistance of Leather (Rotary Platform, Abraser Method). The results are shown below in Table 3.Table 3 - Results of PU Dispersions with Aqueous Polyorganosiloxane Emulsions

[0065] The data for samples Cl, C2, and Inv 1 in Table 3 show that using an EO-PO-EO triblock copolymer as an emulsifier significantly improved compatibility in all PU dispersions under the conditions tested. The data for samples C3 and Inv 1 show that higher viscosity of the polyorganosiloxane (as shown by higher values for G’ and G”) in the internal phase of the emulsion improved the compatibility of the aqueous UHMW polyorganosiloxane emulsion in the three PU dispersions tested.

[0066] In this Reference Example 4, additional emulsion samples were prepared according to the method of Reference Example 1, using the starting materials from Table 1 in the amounts shown below in Table 4.Table 4 - Emulsions with Varying Particle Sizes.

[0067] The data in Table 4 above show different particle sizes for the emulsion samples.

[0068] In this Reference Example 5, the emulsion samples in Table 4 were evaluated in polyurethane coating compositions as described above in Reference Example 3. The results are shown below in Table 5.Table 5 - Results of PU Dispersions with Emulsions from Table 4

[0069] The data in Tables 4 and 5 show that under the conditions tested, large particle size (e.g., Dv50 =18 pm) was detrimental to compatibility in PU dispersions, as shown by Comparative 4 (C4). However, smaller droplet sizes (e.g., Dv50 = 1.5 pm to 7.64 pm) provided aqueous UHMW polyorganosiloxane emulsions that were compatible with the PU dispersions. Without wishing to be bound by theory, it is thought that particle size, Dv50 of > 0 pm to 8 pm, alternatively 2 pm to 8 pm may provide good compatibility with PU dispersions for the aqueous UHMW polyorganosiloxane emulsions described herein.

[0070] In this Reference Example 6, additional emulsion samples were prepared according to the method of Reference Example 1, using the starting materials from Table 1 in the amounts shown below in Table 6.Table 6 - Study of Comparative Emulsifiers

[0071] In this Reference Example 7, the emulsion samples from Table 6 were mixed with polyurethane dispersions and evaluated as described in Example 3. The results are shown below in Table 7.Table 7 - Results of PU Dispersions with Emulsion Samples from Table 6

[0072] The data in Table 7 show that emulsions prepared with surfactants not according to this invention negatively impacted coating performance. Without wishing to be bound by theory, it is thought that the EO-PO diblock copolymer, DOWFAX™ 100N50, competed with the EO- PO-EO triblock copolymer, PLURONIC™ PE6800, to occupy the siloxane / water interface such that the EO-PO diblock copolymer having smaller Mw and therefore more mobility, went first, upon emulsification, to the interface but stabilized the interface less efficiently than EO-PO-EO triblock copolymer. Therefore, the aqueous UHMW polyorganosiloxane emulsion herein may be free of EO-PO diblock copolymer surfactants, such as DOWFAX™ 100N50.

[0073] In this Reference Example 8, additional emulsion samples were prepared according to the method of Reference Example 1, using the starting materials from Table 1 in the amounts shown below in Table 8.Table 8 - Additional Samples with Co-surfactant and with Plasticizer

[0074] In this Reference Example 9, the emulsion samples from Table 8 were combined with polyurethane dispersions and evaluated as described in Reference Example 3. The results are shown below in Table 9.Table 9 - Results of PU Dispersions with Aqueous Polyorganosiloxane Emulsions from Table 8

[0075] The data in Table 9 with Inv 8 suggest that a small amount of co-surfactant may be used with the EO-PO-EO triblock copolymer and still maintain compatibility and abrasion resistance performance. Sample Cl 1 (comparative 11) showed that using a plasticizer instead forming the UHMW polyorganosiloxane in the emulsion herein was detrimental to compatibility with all PU dispersions tested.

[0076] In this Reference Example 10, additional emulsion samples were prepared according to the method of Reference Example 1, using the starting materials from Table 1 in the amounts shown below in Table 10.Table 10 - Study of Different EO-PO-EO Emulsifiers

[0077] The data in Table 10 showed that different EO-PO-EO triblock copolymers could be used to prepare emulsions with particle size < 8 pm. Sample C12 (comparative 12) showed that when the amount of chain extender was low (as shown by the SiH / Vi ratio < 0.9), molecularweight and viscosity of the polyorganosiloxane formed via emulsion polymerization were low, as shown by the low G’ and G” values.

[0078] In this Reference Example 11, the emulsion samples from Table 10 were added polyurethane dispersions and evaluated as described in Reference Example 3. The results are shown below in Table 11.Table 11 - Results of PU Dispersions with Emulsions from Table 10

[0079] Without wishing to be bound by theory, it is thought that sample C12 had lower molecular weight and lower viscosity (as shown by the low G’ and G” values) due to insufficient amount of Chain Extender (low SiH / Vi ratio), and may have failed compatibility due to the relatively low molecular weight and low viscosity of the polyorganosiloxane (as shown by G’ < 400 Pa and G” < 2,000). The data in Table 10 show that different EO-PO-EO emulsifiers can be used in the present invention.

[0080] In this Reference Example 12, additional emulsion samples were prepared using the starting materials from Table 1 in the amounts shown below in Table 12. Different mixers were used to prepare the samples. A small dental mixer (100 g capacity) was used to prepare sample Inv 15. A large dental mixer (400 g capacity) was used to prepare samples Cl 3 and Cl 4.Table 12 - Study of Mixing Equipment

[0081] In this Reference Example 13, the emulsion samples from Table 12 were combined with polyurethane dispersions and evaluated as described in Reference Example 3. The results are shown below in Table 13.Table 13 - Results of PU Dispersions with Aqueous Polyorganosiloxane Emulsions Samples from table 12

[0082] The samples prepared on the larger dental mixer were not mixed sufficiently. Portions of the samples were not emulsified, and without wishing to be bound by theory, it is thought that this is the reason for these failing compatibility in PU 1 and PU 2.

[0083] In this Reference Example 14, additional emulsion samples were prepared using the starting materials from Table 1 in the amounts shown below in Table 14. Different amounts of Plasticizer were added to some of the samples when mixing the Vi Reactant and the ChainExtender.Table 14 - Plasticizer Study

[0084] In this Reference Example 15, the emulsion samples from Table 14 were combined with polyurethane dispersions and evaluated as described in Reference Example 3. The results are shown below in Table 15.Table 15 - Results of PU Dispersions with Aqueous Polyorganosiloxane Emulsions SamplesContaining Plasticizer

[0085] One skilled in the art would recognize that the presence of the plasticizer will impact the storage modulus and loss modulus of the discontinuous phase of the aqueous emulsion. Without wishing to be bound by theory, it is thought that a small amount of plasticizer (e.g. , 0 to 5%) may be used in preparation of the aqueous UHMW polyorganosiloxane emulsion described herein. Sample C15 (comparative 15) showed that when the amount of plasticizer was too high, G’ and G” values dropped and compatibility was not as good as in working examples 16-18.

[0086] Particle size was measured as follows: The average droplet size (or average particle size) of the emulsion was measured by laser diffraction. Suitable laser diffraction techniques are well known in the art. The average particle size is obtained from a particle size distribution (PSD). The PSD can be determined on a volume, surface, length basis. The volume particle size is equal to the diameter of the sphere that has the same volume as a given particle. The term Dv represents the average volume particle size of the discontinuous (internal) phase. Dv 0.5 (or Dv50) is the particle size measured in volume corresponding to 50% of the cumulative particle population. In other words if Dv50 = 10 pm, 50% of the particle have an average volume particle size below 10 pm and 50% of the particle have a volume average particle size above 10 pm. Unless indicated otherwise, all average volume particle sizes are calculated using Dv50. Average particle size was measured using a Maslersizer™ 3000 laser diffraction particle size analyzer from Malvern Instruments (granulometer).

[0087] Loss Modulus and Storage Modulus were measured as follows: First, UHMW polyorganosiloxane extraction was performed as follows: Mix same quantity of emulsion with IPA (isopropyl alcohol) to break emulsion in a bottle. Keep solely the UHMW polyorganosiloxane in the bottle and repeat the operation twice. Put in a cup the UHMW polyorganosiloxane extract in an oven at 120 °C for 30 minutes to dry the UHMW polyorganosiloxane. Next, the viscoelastic properties of the UHMW polyorganosiloxane were measured in oscillation mode with a rheometer (an Anton Paar Physica MC 301). Measuring conditions: temperature: 25°C; Frequency sweep: From 100 to 0.1 rad / s; Spindle: 25PP; Gap: 1mm; Shear strain: 0,1%; G' and G" values were taken at 0.1 rad / s.

[0088] Viscosity: Viscosity of the Vi Reactant and Chain Extender was measured by rotational viscometry using a Brookfield viscometer with LV, Spindle 4 @ 6 RPM at 25 °C.

[0089] Problems to be Addressed: An aqueous polyorganosiloxane emulsion that is stable in an aqueous coating composition and stable in the presence of organic solvents, while at the sametime contains less than one weight part aromatic solvent per million weight parts and less than 0.1% cyclic polyorganosiloxanes is desirable to the coating industry. Thus, there exists an industry need to identify processes to prepare emulsions of ultra-high molecular weight polyorganosiloxanes that do not require specialized surfactants containing aromatic solvents, nor require expensive emulsification equipment. In addition, the aqueous polyorganosiloxane emulsion needs to be compatible with polyurethane coating compositions to produce coatings with no or minimal fisheyes and coating appearance defaults associated with the instability of ultra-high molecular weight polyorganosiloxane emulsions in water-based coating compositions. There is also a need in the coatings industry for more efficient abrasion resistance additives.

[0090] Solution; The inventors surprisingly found that the use of an ethylene oxide / propylene oxide triblock copolymer as emulsifier for making aqueous UHMW polyorganosiloxane emulsions having Dv 50 of < 8 pm, alternatively 2 pm to 8 pm, show improved stability when formulated in water-based coating compositions and produced coatings with good abrasion resistance.

[0091] Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. 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 or emulsion 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., IT, and III.

[0092] As used herein, ultra-high molecular weight (UHMW) polyorganosiloxane, means a linear, or substantially linear, polyorganosiloxane with storage modulus and loss modulus, which are each greater than those of a conventional silicone gum when measured according to the test method described above. The UHMW polyorganosiloxane also has a Mw and corresponding viscosity greater than those of the conventional silicone gum.

[0093] The abbreviations used herein have the definitions in Table A.Table A - Abbreviations

Claims

CLAIMS:

1. An aqueous ultra-high molecular weight polyorganosiloxane emulsion comprising:(A) an ultra-high molecular weight polyorganosiloxane having a storage modulus > 1,500 Pa and a loss modulus > 2,000 Pa, each measured at an angular velocity of 0.1 radian / second and 25 °C;(B) an emulsifier comprising an ethylene oxide / propylene oxide / ethylene oxide triblock copolymer; and(C) water; and with the provisos that the emulsion has a discontinuous phase dispersed in a continuous phase, the discontinuous phase comprises (A) the ultra-high molecular weight polyorganosiloxane, and the discontinuous phase has an average droplet size Dv50 < 8 pm; the continuous phase comprises (C) the water.

2. The emulsion of claim 1, wherein (A) the ultra-high molecular weight polyorganosiloxane comprises unit formula: (R1R2R3SiOi / 2)2(R2R3SiO2 / 2)u(R2R3SiD2 / 2)v, wherein each R1is independently selected from the group consisting of H and an alkenyl group of 2 to 12 carbon atoms; each R2and each R3are independently selected from the group consisting of alkyl groups of 1 to 12 carbon atoms and aryl groups of 6 to 12 carbon atoms; each D is an independently selected divalent hydrocarbyl group of 2 to 12 carbon atoms; subscripts u and v have values sufficient to give the polyorganosiloxane storage modulus of 3,000 Pa to 30,000 Pa and loss modulus 3,000 Pa to 20,000 Pa.

3. The emulsion of claim 2, wherein (A) the ultra-high molecular weight polyorganosiloxane has formulaeach R4is independently selected from the group consisting of vinyl, allyl, and hexenyl; each R2and each R3are independently selected from the group consisting of methyl and phenyl; each D has empirical formula -CwH2w-, wherein each subscript w is independently 2, 3 or 6; each subscript x independently has a value of 10 to 25,each subscript y independently has a value of 900 to 1000, subscript z > 4,000, and subscripts x, y, and z have values sufficient to give the ultra-high molecular weight polyorganosiloxane storage modulus of 5,000 Pa to 25,000 Pa and loss modulus 4,000 Pa to 19,000 Pa.

4. The emulsion of any one of claims 1 to 3, wherein the ethylene oxide / propylene oxide / ethylene oxide triblock copolymer has formula:subscript a has an average value of 30 to 90, subscript b has an average value 25 to 75, and subscript c has an average value of 75 to 110.

5. The emulsion of claim 4, wherein the ethylene oxide / propylene oxide / ethylene oxide triblock copolymer formula has: subscript a has an average value of 39 to 82, subscript b has an average value of 31 to 67, and subscript c has an average value of 82 to 99.

6. The emulsion of any one of claims 1 to 5, wherein the emulsion has56 weight % to 62 weight % of (A) the ultra -high molecular weight polyorganosiloxane, 0 to 5 weight % of (A4) a plasticizer,2.9 weight % to 8 weight % of (B) the surfactant, and a balance to 100 weight % of (C) the water.

7. The emulsion of any one of claims 1 to 6, wherein the emulsion has average droplet size 2 pm < Dv50 < 8 pm.

8. A process for preparing the emulsion of any one of claims 1 to 7, said process comprising:1) emulsifying, under conditions to effect hydrosilylation reaction, starting materials comprising54 weight % to 60 weight %, based on combined weights of starting materials (Al), (A2), (A3), and (A4), of (Al) a bis-alkenyl-terminated polydiorganosiloxane,1.10 weight % to 1.30 weight %, based on combined weights of starting materials (Al), (A2), (A3), and (A4), of (A2) a bis-hydrido-terminated polydiorganosiloxane,0.5 weight % to 1 weight %, based on combined weights of starting materials(Al), (A2), (A3), and (A4), of (A3) a hydrosilylation reaction catalyst composition,0 to 5 weight %, based on combined weights of starting materials (Al), (A2), (A3), and (A4), of (A4) a plasticizer;(B) the emulsifier; and(C) the water, with the proviso that starting materials (A2) and (Al) are provided in amounts sufficient to provide a molar ratio of silicon bonded hydrogen atoms to silicon bonded alkenyl groups of at least 0.95.

9. The process of claim 8, wherein (Al) the bis-alkenyl-terminated polydiorganosiloxane has formula:, wherein each R4is independently selected from the group consisting of vinyl, allyl, and hexenyl; each R2and each R3are independently selected from the group consisting of methyl and phenyl; and subscript y has an average value of 900 to 1 ,000.

10. The process of claim 8 or claim 9, wherein (A2) the bis-hydrido-terminated polydiorganosiloxane has formula:, wherein each R2and each R3are independently selected from the group consisting of methyl and phenyl; and subscript x has an average value of 10 to 25.

11. The process of any one of claims 8 to 10, wherein (A3) comprises an aqueous non-ionic emulsion of Karstedt’s catalyst.

12. An aqueous coating composition prepared by mixing starting materials comprising:0.1 weight % to 20 weight % of (1) the aqueous ultra-high molecular weight polyorganosiloxane emulsion of any one of claims 1 to 7, and80 weight % to 99.9 weight % of (II) an aqueous composition comprising water and an organic polymeric binder.

13. The aqueous coating composition of claim 12, wherein the polymeric binder is selectedfrom the group consisting of a urethane binder, an acrylic binder, and a combination thereof.

14. The aqueous coating composition of claim 12 or claim 13, further comprising an additional starting material 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, (K) an antifoam, (L) a water repellent additive, (M) an antiblocking additive, (N) an abrasion resistance additive (other than the UHMW polyorganosiloxane), (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 coalescing solvent, (W) an opacifier, (X) an extender, (Y) a plasticizer, (Z) a co-surfactant and a combination of two or more thereof.

15. A method for treating leather comprising: i) applying the aqueous coating composition of any one of claims 12 to 14 on a surface of a leather article, and ii) drying the aqueous coating composition to form a coating on the surface of the leather article.

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