EP4655350A1 - Wear resistant and lubricating coating composition for flexible substrates - Google Patents

Abstract

A coating composition for flexible substrates, including a binder resin, a lubricating component in the form of lubricating filler particles of a carnauba wax, hydrocarbon wax and/or polyethylene, and a solvent. The coating composition is wear resistant and is substantially free of fluoropolymers.

Description

WEAR RESISTANT AND LUBRICATING COATING COMPOSITION FOR FLEXIBLE SUBSTRATES CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No.63/481,704 filed on January 26, 2023 which is incorporated by reference in its entirety. FIELD [0002] The present disclosure relates to a wear resistant, lubricating coating composition for coating flexible substrates, for example, power transmission belts. BACKGROUND [0003] Transmission belts within mechanical drive systems can experience a variety of forces that can cause wear and tear. Coatings may be applied to transmission belts to add resistance, prevent premature failure, and suppress noise. Known transmission belt coatings typically contain fluoropolymers, which may potentially include minor amounts of per/polyfluoroalkyl substances (PFAS). The fluoropolymer regulatory landscape has become increasingly concerned about PFAS as a constituent of substances and/or mixtures, so it would be desirable to provide a coating composition for flexible substrates, for example, power transmission belts, which are substantially free of PFAS. SUMMARY [0004] A coating composition for flexible substrates, including a binder resin, a lubricating component in the form of lubricating filler particles of a hydrocarbon wax and/or polyethylene, and a solvent. The coating composition is wear resistant and is substantially free of fluoropolymers. [0005] In one form thereof, the present disclosure provides a coating composition for flexible substrates, comprising: a binder resin, a solvent, and a lubricating component comprising at least one of: lubricating filler particles comprising a hydrocarbon wax having a melting point from 80^oC to 150^oC, as determined by ASTM D87; polyethylene having a melting point from 80^oC to 150^oC, as determined by ASTM D87. [0006] In another form thereof, the present disclosure also provides a coated flexible substrate, comprising: a flexible substrate; and a non-continuous coating impregnated within the flexible substrate, comprising: a binder resin; a lubricating component comprising at least one of: a hydrocarbon wax having a melting point from 80^oC to 150^oC, as determined by ASTM D87; polyethylene having a melting point from 80^oC to 150^oC, as determined by ASTM D87. BRIEF DESCRIPTION OF THE DRAWINGS [0007] The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description taken in conjunction with the accompanying drawings. These above-mentioned and other features of the disclosure may be used in any combination or permutation. [0008] FIG. 1 is a sectional view of a power transmission belt including a toothed elastomeric body with a coated fabric substrate adhered to the toothed surface; [0009] FIG. 2a illustrates a fabric substrate coated with the coating composition within the scope of examples 1-10 described in the present disclosure; [0010] FIG. 2b illustrates a fabric substrate coated with a known coating composition similar to comparative coatings 1-11 described in the present disclosure; and [0011] FIG. 3 is a sectional view of a portion of a coated fabric substrate according to Example 7. [0012] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate the disclosure, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner. DETAILED DESCRIPTION [0013] The present disclosure proves a coating composition that may be applied to flexible structures, such as transmission belts. Further, the present disclosure provides a fluoropolymer-free lubricating coating composition. [0014] I. Definitions [0015] For purposes of the following detailed description, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about." For example, numerical ranges provided for weight percentages of components or amounts of components added should be construed as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. [0016] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements. [0017] Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges from (and including) the recited minimum value of 1 to the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. [0018] The use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, the use of "or" means "and/or" unless specifically stated otherwise, even though "and/or" may be explicitly used in certain instances. [0019] “Wax” is used herein to describe a material formed of a mixture of alkanes of various chain lengths and/or a modified alkane which also includes other functional groups such as esters and/or amines in the chains, and which may demonstrate phase change characteristics, wherein the waxes tend to be solid at room temperature (20^oC), have a melting point above about 40^oC, and are able to absorb heat while showing little volume change during melting. [0020] “PFAS” is used herein to describe per- and polyfluorinated substances, including synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain, for example perfluorinated monomers and oligomers such as perfluorooctanoic acid. [0021] “Wet” coating composition is used herein to describe a liquid coating composition before it is cured. [0022] “Dry” coating composition is used herein to describe a coating composition after it is cured. [0023] “Transmission belt” or “timing belt” is used herein to describe a mechanical element comprising a loop of flexible materials used to mechanically connect several rotating shafts. [0024] “Flexible” as used in connection a substrate which may be coated, means capable of being bent or disposed to yielding. [0025] “Non-continuous” as used in connection with a coating, means that the coating is not necessarily a continuous film, but may have interruptions, voids, or gaps therein. [0026] II. Composition of Coating [0027] The present disclosure provides a PFAS free coating for power transmission belts. The coating composition increases wear resistance and lubrication of a coated transmission belt. The coating composition may comprise of a binder resin, a lubricating component, and a solvent. [0028] A. Binder Resin [0029] Binder resins provide adhesion to a substrate and improve the mechanical properties, such as elongation, and may be self-curable or cure with the aid of a curing agent. The binder resin may allow the coating to follow the elongation of a coated belt during operation without cracking or disbanding or suffering thermo-mechanical fatigue. A binder resin is referred to herein interchangeably as a ‘binder’, ‘resin binder’ or ‘binder resin’, ‘base’, or ‘binder system’ and, depending on the amount of lubricating component desired, may provide the bulk of the present coatings when applied to a substrate. [0030] The binder resin of the present disclosure may be a polymer binder that includes hydroxyl functional polyester reactive with an isocyanate and polyurethane reactive with a carbodiimide. Water-based polycarbonate PUDs cross-linked with carbodiimide may produce a coating film with a higher melting point than water-based polyester that is closer to the melting point of solvent-based polyurethane. Binders of the present disclosure may be supplied as solvent borne or water borne systems. Among the polymers suitable for use as binders in coatings of the present disclosure, solvent-free aliphatic polyester polyurethane dispersions, aliphatic polycarbonate waterborne polyurethane dispersions, polycarbonate ester polyurethane dispersions, hydroxyl-bearing polyesters, acrylic polyols, aliphatic polyisocyanate resins, aliphatic polyisocyanates, VOC-free polycarbodiimides, and water dilutable, activated, multi-functional poly carbodiimides may be used. [0031] The coating composition provided by the present disclosure can comprise a weight percentage of binder resin, for example, from 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. % to 40 wt. %, 45 wt. %, 50 wt. %, 60 wt. %, or any range including any two of these values as endpoints, such as 20 wt. % to 60 wt. %, 25 wt. % to 50 wt. %, 30 wt. % to 45 wt. %, or 35 wt. % to 40 wt. %, wherein the weight percent is based on the total weight of the “wet” coating composition. [0032] Binder resin may be present in the cured coating composition, in an amount from 30 wt.%, 35 wt.%, 40 wt.%, 50 wt.% to 60 wt.%, 70 wt.%, 80 wt.%, 90 wt. %, or any range including any two of these values as endpoints, such as 30 wt.% to 90 wt.%, 35 wt.% to 80 wt.%, 40 wt.% to 70 wt.%, or 50 wt.% to 60 wt.%, wherein the weight percent is based on the total weight of the “dry” coating composition. [0033] B. Lubricating Component [0034] Another component of the coating composition is a lubricating component. The lubricating component acts to reduce friction between the surface of a coated substrate, such as a coated transmission belt, and another surface, such as a mechanical gear. [0035] The coating composition of the present disclosure may comprise a lubricating component that is an organic polymer made in the absence of fluorine-carbon bonds. [0036] The lubricating component may be a wax which is solid at room temperature (20^oC) and has a melting point at temperatures from 80°C , 90°C, 100°C, 110°C to 120°C, 130°C, 140°C, 150°C, or any range including any two of these values as endpoints, such as 80°C to 150°C, 90°C to 140°C, 100°C to 130°C, or 110°C to 120°C. [0037] Such a wax as described may be a hydrocarbon wax, ethylene bis stearamide (EBS), alkane waxes, amide waxes, polyethylene waxes, carnauba waxes, and any combination thereof. [0038] Carnauba wax is a natural wax that comes from the leaves of the carnauba palm, a plate native to northeastern Brazil. Carnauba wax comprises of aliphatic esters, diesters, 4-hydroxycinnamic acid, w-hydroxycarboxylic acids, and fatty alcohols. [0039] Carnauba wax may comprise particles having a median diameter, or D50, less than 15 µm, less than 12 µm, less than 8 µm, less than 6 µm, less than 4 µm, less than 2 µm, less than 1 µm, less than 0.5 µm, or less than 0.1 µm, as determined by dynamic light scattering measured through Mie scattering and Fraunhofer diffraction technique as per ISO 13320-1 practice. [0040] The lubricating component may comprise small particles having a median diameter, or D50, from 0.1 µm, 1 µm, 5 µm, 10 µm, to 20 µm, 30 µm, 40 µm, 50 µm, or any range including any two of these values as endpoints, such as 0.1 µm to 50 µm, 1 µm to 40 µm, 5 µm to 30 µm, or 10 µm to 20 µm as determined by dynamic light scattering measured through Mie scattering and Fraunhofer diffraction technique as per ISO 13320-1 practice. [0041] The coating composition provided by the present disclosure may comprise a weight percentage of lubricating component, for example, from 1 wt. %, 2 wt. %, 5 wt. % to 10 wt. %, 15 wt. %, 20 wt. %, or any range including any two of these values as endpoints, such as 1 wt. % to 20 wt. %, 2 wt. % to 15 wt. %, or 5 wt. % to 10 wt. %, wherein the weight percent is based on the total weight of the “wet” coating composition. [0042] The coating composition of the present disclosure may have a weight ratio of lubricating component to the total of dry binder resin and dry lubricant from 0.1, 0.25, 0.3, to 0.5, 0.66, 0.9 or any range including any two of these values as endpoints, such as 0.1 to 0.9, 0.25 to 0.66. or 0.3 to 0.5. [0043] Lubricating component may be present in the cured coating composition, in an amount from 10 wt.%, 20 wt.%, 30 wt.% to 40 wt.%, 50 wt.%, 60 wt. %, or any range including any two of these values as endpoints, such as 10 wt.% to 60 wt.%, 20 wt.% to 50 wt.%, or 30 wt.% to 40 wt.%, wherein the weight percent is based on the total weight of the “dry” coating composition. [0044] C. Solvent [0045] The coating composition may include one or more solvents. Exemplary solvents include water, alcohols such as C1-C8 alcohols including methanol, ethanol, isopropanol, and t-butanol, C2-C8 ketones including acetone, C2-C20 ethers including dipropylene glycol methyl ether and other protic or non-protic solvents like dimethylsulfoxide or N-methylpyrrolidone. [0046] The solvent may be present in the composition in an amount from 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. % to 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, or any value encompassed by these endpoints, such as 15 wt. % to 50 wt. %, 20 wt. % to 45 wt. %, 25 wt. % to 40 wt. %, or 30 wt. % to 35 wt. %, wherein the weight percent is based on the total weight of the “wet” coating composition. [0047] After the coating has been applied and cured, the total coating composition may be substantially free of solvent. In other words, the solvent may be present in the composition in an amount from 0 wt.%, 0.1 wt.% or 0.15 wt.% , 0.2 wt.% or any value encompassed by these endpoints, such as 0 wt. % to 0.2 wt. %, or 0.1 to 0.15 wt. %, wherein the weight percent is based on the total weight of the “dry” coating composition. [0048] D. Additives [0049] Additives may be present in the coating composition of the present disclosure in addition to the components described above. These additives may comprise components to improve stability, applicability and aesthetics. Additives that may be included in the present coating composition may include defoamers, thickeners, surface wetting agents or surfactants, tinting paste, and pigments. [0050] The total amount of such additives, based on the “wet” weight of the coating composition prior to a substrate followed by curing, may comprise from 0 wt. %, 5 wt. %, 10 wt. % to 20 wt. %, 30 wt. %, 40 wt. %, or any other range combination using these endpoints, such as 0 wt.% to 40 wt.%, 5 wt. % to 30 wt. %, or 10 wt. % to 20 wt. %, wherein the weight percentage is based on the total weight of the “wet” coating composition. [0051] After the coating is applied and cured, the additives may be present in the coating composition in a total amount ranging from 0 wt. %, 2 wt.%, 4 wt.% to 6 wt.%, 8 wt.%, 10 wt. %, 15 wt.%, or any range including any two of these values as endpoints, such as 0 wt.% to 10 wt.%, 2 wt.% to 8 wt.%, or 4 wt.% to 6 wt.%, wherein the weight percent is based on the total weight of the “dry” coating composition. [0052] III. Method of Coating a Flexible Substrate [0053] The coating composition of the present disclosure may be applied to a substrate such as a woven polymeric fabric material. Suitable substrates may fabrics such as polyester, polyamide, aramide, cotton, or other polymeric materials. [0054] A. Application [0055] To apply the coating composition of the present disclosure, the coating composition may be deposited onto the fabric substrate via a variety of methods. Methods of application may include coating by dipping, spraying, knife-on-air, and knife-over-roller. Once applied, the coating composition impregnates the fabric substrate such that the coating composition is within the fabric substrate. The coating composition may penetrate at least 20- 30% into the weave of the fabric substrate, based on the thickness of the fabric substrate, which may be determined by any imaging method, such as using a scanning electron microscope as in Example 3 below. [0056] i. Dipping [0057] To coat the fabric substrate using a dipping process, the fabric substrate is dipped into a reservoir of the coating composition such that the fabric substrate become impregnated with the coating composition. The coated substrate is then removed from the reservoir and set out to cure. [0058] ii. Spraying [0059] Spraying is another form of application that may be used to apply the coating composition of the present application. Spraying comprises using a spray of coating composition particles or droplets to deposit the coating composition onto a substrate. The substrate may be passed under a spray or otherwise exposed to a spray of the coating composition for a predetermined amount of time to deposit a desired amount of coating composition. [0060] iii. Knife-on-air [0061] Knife-on-air or air knife coating is a process that applies a predetermined amount of coating composition to a substrate. The process comprises placing the substrate on a series of rollers that move the substrate under a mechanism that deposits the coating composition, such as a reservoir that drips the coating composition onto the substrate. An excess amount of coating composition may be deposited onto the substrate. To remove the excess coating, the coated substrate is passed under an air jet that blows the excess coating off of the substrate. The positioned angle of the air jet to the substrate and the velocity of the air are calculated such that a predetermined amount of coating composition remains on the substrate. The coating composition of the present disclosure may be applied to the fabric substrate using the knife-on-air method of application. [0062] iv. Knife-over-roller [0063] Another process to apply the coating composition of the present disclosure to the fabric substrate is knife-over-roller or gap coating. This process comprises placing the substrate on a series of rollers that pass under a mechanism that deposits a coating composition, similar to the knife-on-air process described above. The amount of coating composition that is deposited may be more than necessary to coat the substrate. To remove the excess coating, the substrate covered in coating is passed through a gap created between the substrate and a knife positioned above the substrate. The positioning of the knife is predetermined to scrape off coating in excess and leave only a desired amount of coating on the substrate as it passes through the gap. [0064] B. Curing [0065] Once the fabric substrate has been coated with the coating composition, the coating is cured or dried at temperatures from 130°C, 140°C, 145°C, to 150°C 160°C, 170°C, or any other range combination using these endpoints, such as 130°C to 170°C, 140°C to 160°C, or 145°C to 150°C. The coating composition may be cured at the temperatures previously listed from 2 min, 6 min, 10 min, 14 min, 18 min, 20 min, or any other range combination using these endpoints, such as 2 min to 20 min, 6 min to 18 min, or 10 min to 14 min. If the coating composition contains solvent, the coating composition may not be cured but instead fully cure during the vulcanization process. [0066] C. Vulcanization Process [0067] Once the fabric substrate has been coated, the fabric substrate may be applied to an elastomeric body, such as an endless polymeric belt, and permanently bonded to the elastomeric body through vulcanization. During the vulcanization process, the coated fabric substrate is laminated onto the elastomeric body using high pressures and high temperatures, such as 170°C/20min. The high temperatures and pressures may not soften the coating composition. The resulting product is the fabric substrate adhered to the elastomeric body, with the outer layer of the fabric substrate comprising the binder resin and lubricant that permeates the fabric substrate such that the entire structure possesses greater durability towards wear against pulleys than similar structures without the coating composition. [0068] As seen in FIG.1, a power transmission belt 10 includes a fabric substrate 30 adhered to the surface of an elastomeric 15 body at 20. The coating composition may be impregnated into fabric substrate 30, wherein the depth of impregnation shown at 32 may more than 35%, more than 50%, more than 65%, more than 75% or more than 90% of the total thickness of the fabric substrate 30. [0069] IV. Properties of Coating [0070] The coating composition of the present disclosure exhibits a variety of properties including a high melting point, a low melt flow viscosity, and being fluoropolymer free. [0071] A. Resistance to Wear [0072] During the operation of a gear or pulley, a belt or other elastomeric body vulcanized to a fabric substrate may experience wear and tear due to the friction between the belt and gear/pulley. The coating composition described in the present disclosure increase the durability and wear resistance of a belt with a coated fabric substrate. This increased durability may increase the lifetime and use of the belt and reduce the risk of failure. [0073] B. Melt Viscosity [0074] The melt viscosity of a polymer at a given temperature is a measure of the rate at which chains can move relative to each other, such as the ease of rotation about the backbone bonds of the polymer. Polymers with less flexible chains are more viscous in their melting range than polymers with flexible chains. [0075] The coating composition of the present disclosure may have a melt flow viscosity at 150^oC from less than 1000 cP, less than 800 cP, less than 600 cP, to less than 400 cP, less than 200cP, less than 100 cP, or greater that 10 cp, or any range including any two of these values as endpoints, using a rotational rheometer with 60 mm plate-plate geometry, 1mm gap, and shear rate equal to 5 s^-1, according to ASTM D2196. [0076] D. Fluoropolymer Free [0077] With mounting regulation of PFAS, including fluoropolymers, there is a draw to have PFAS free coating compositions. The present coating compositions may lack fluoropolymers, wherein the coating composition is fluoropolymer-free. Per- and polyfluoroalkyl substances (PFAS) are fluorine-containing chemical compounds including perfluoroalkyl acids (PFAAs) such as perfluorooctanoic acid (PFOA), and/or perfluorooctane sulfonate (PFOS). The coating compositions of the present disclosure may be essentially, substantially, or completely free of PFAS. [0078] By essentially PFAS-free it is meant that the coating compositions of the present disclosure comprises a total amount of perfluorinated and polyfluorinated alkyl compounds of 1 wt.% or less, based on a total weight of the coating composition and/or have a total content of PFAS less than 1 ppm, based on a total weight of the coating. By substantially PFAS-free it is meant that the coating compositions of the present disclosure comprises a total amount of perfluorinated and polyfluorinated alkyl compounds of 0.1 wt.% or less, based on a total weight of the coating composition and/or have a total content of PFAS less than 0.1 ppm, based on a total weight of the coating. By completely PFAS-free it is meant that the coating compositions of the present disclosure comprises a total amount of perfluorinated and polyfluorinated alkyl compounds of 0.01 wt.% or less, based on a total weight of the coating composition and/or have a total content of PFAS less than less than 0.01 ppm, based on a total weight of the coating. EXAMPLES [0079] Aspects of the present disclosure are further illustrated by reference to the following examples. It will be apparent to those skilled in the art that many modifications, both to materials, and methods, may be practiced without departing from the scope of the disclosure. [0080] Compositions were formulated as described below according to the coating compositions of the present disclosure. The coating compositions were applied to a fabric substrate and the properties of the impregnated coatings were tested to yield the following results. Example 1 Exemplary Coating Compositions [0081] Referring to table 1, comparatives (Comp.) 1-11 were prepared using the following known coating compositions. Additionally, example compositions 1-4 of the present disclosure were formulated using the following compositions. [0082] Table 1 sets forth the compositions of comparative 1-2 and example compositions 1-4, as described below. Table 1: Comparative and Example Coating Compositions Component Function Comp.1 Comp.2 Ex.1 Ex.2 Ex.3 Ex.4 Component Function Comp.1 Comp.2 Ex.1 Ex.2 Ex.3 Ex.4 Additional Additives 21.27 17.05 19.33 19.79 19.79 19.79 xamp e Testing of Exemplary Coating Compositions [0083] Comparative compositions 1-11 and example compositions 1-5 were prepared by mixing the liquid ingredients and stirring in or processing through the mill the powders until properly dispersed, and until a homogeneous paint was obtained free of obvious aggregates and lumps; they were subsequently applied to a fabric substrate by knife-on-air method and tested to determine the coefficient of friction of a fabric substrate coated with the coating compositions. [0084] Table A illustrates the testing parameters for each of the following tests. Table A: Test Parameters Time (s) Load RPM Disc Radius Linear sp (m/s) [0085] The damage score was measured for example compositions 1-4 and comparatives 1-11. Damage score is measured by comparison with image standards in a calibrated scale and is an indicator of actual coating survival after tribological test according to ASTM G99. Table 2 illustrates examples of coated substrates after exposed to tribological testing that exhibits various damage scores.

Table 2: Damage Scores Coating Damage Image Damage Score Description

Coating Damage Image Damage Score Description [0086] Table 3 illustrates the coefficient of friction (CoF) measured through the tribometer as per ASTM G99 for example compositions 1-4 and comparatives 1-11. As seen in the table below, example compositions 1-4 generally display a lower CoF than comparatives 1-11, reducing the amount of wear on the fabric substrate adhered on an elastomeric body (such as a belt). Table 3: Comparative and Example Coating Composition Properties Sample Lubricant Type Average Initial Final Delta Z Damage Sample Lubricant Type Average Initial Final Delta Z Damage CoF CoF CoF CoF value Score [0087] FIGS.2a and 2b correlate to the results of table 2. Both table 2 and FIGS. 2a and 2b demonstrate that a fabric substrate coated with the coating composition of the present disclosure exhibits better wear resistance than a fabric substrate coated with a known coating composition, such as the comparatives. [0088] FIG. 2a depicts a fabric substrate coated in a coating composition within the scope of the coating formulations of examples 1-10 described in the present disclosure 100a. FIG. 2b depicts a fabric substrate coated in a known coating composition 100b similar to the comparative coatings disclosed herein. Each coated fabric substrate in FIGS.2a and 2b were subjected to linear reciprocating abrasion at a constant temperature of 170°C. The reciprocating abrasion at 170°C is meant to simulate the conditions that the coated fabric substrates would be subjected to once coupled to an elastomeric body, such as a belt, that rubs up against a pulley or gear. [0089] After 500 stroke of the reciprocating abrasion, the fabric substrate coated with the coating composition similar to the example coating compositions of the present disclosure 100a had no visible marks, as seen in FIG.2a. The fabric substrate coated with the comparative known coating composition 100b suffered noticeable wear 140, as seen in FIG. 2b. This result is supported by the values of table 2. Examples 1-4 have an average coefficient of friction from 0.183 to 0.248, while comparatives 1-11 have an average coefficient of friction from .230 to 0.609. Due to the lower CoF, a fabric substrate coated with the coating composition of the present disclosure has increased wear resistance and does not show visible damage on the surface of the substrate. Example 3 Cross-section of Fabric Substrate Coated with Coating Composition [0090] FIG. 3 illustrates a cross-section image 200 of an elastomeric body 210 with a fabric substrate 220 coated with the coating composition 230 of the present disclosure. Image 200 was obtained using a scanning electron microscope with electron acceleration of 5 to 20 kV, working distance between 10 and 20 mm, and backscattered electrons detector at 50x magnification. [0091] The coating composition 230 included FeO as a marker, which appear in Fig. 3 as small black dots, and was formulated using the formulation of example 7 described below. The coated fabric substrate 220 is adhered onto elastomeric body 210 forming a fiberglass tensile cord layer 215. The concentration and extent of penetration of the coating composition 230 into the fabric substrate 220 may be seen via the marker. The depth of impregnation 232 is more than 50% of the total thickness of the fabric substrate 220. Example 4 Exemplary Coating Compositions [0092] Table 4 illustrates the compositions for comparative 1 and example compositions 5-9. The filling factor is a measure of the percent weight of lubricant of the total weight of the binder and lubricant. There is a significant increase in all the tribological properties when the filling factor exceeds 10% of weight of lubricant on the total weight of the binder and lubricant, resulting in a better damage score and lower CoF. (See Table 4) Table 4: Range of Identified Wax Lubricant Concentration Component Component Comp.1 Ex. 5 Ex.6 Ex.7 Ex.8 Ex. 9 Ex.10 Function 8 0 8 4 Example 5 Properties of Exemplary Coating Compositions [0093] Table 5 illustrates the amount of lubricant, binder resin, and percent lubricant on binder for comparative 1 and examples 5-11. The CoF for comparative 1 and each of examples 5-11 were tested using ASTM G99. Examples 5-11 were shown to have a lower CoF than the comparative, which results in better resistance to wear from use of the fabric substrate vulcanized on an elastomeric body against a pulley or gear. Table 5: Measured Tribological Properties for a Range of Wax Lubricated Paints Lubricant Binder Lubricant % Average Initial Final Z Damage Delta CoF 6 8 8 4 Lubricant Binder Lubricant % Average Initial Final Z Damage Delta CoF Solids Resin on Binder CoF CoF CoF Value Score 1 7 [0094] As shown in Examples 1-5, example compositions 1-9 show increased wear resistance over known comparative coating compositions, when applied to a fabric substrate. Due to the increased wear resistance, the coating compositions of the present disclosure may increase the lifetime of a coated fabric substrate adhered to an elastomeric body used in a transmission belt assembly. [0095] Wherein particular examples of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims. Example 6 Exemplary Coating Compositions – Carnauba Wax [0096] Referring to Table 6, example compositions 11 and 12 of the present disclosure were formulated using the following compositions. Table 6: Example Coating Compositions 11 and 12 Formulation Component Component Ex.11 Ex. 12 Component Component Ex.11 Ex. 12 Function (wt. %) (wt. %) 9 [0097] Table 7 illustrates the properties tested for Ex.11 and Ex.12 using the testing parameters previously described in Table A. The damage score was measured for example compositions 11 and 12. Damage score is measured by comparison with image standards (Table 2) in a calibrated scale and is an indicator of actual coating survival after tribological test according to ASTM G99. Table 7 illustrates examples of coated substrates after exposed to tribological testing that exhibits various damage scores. [0098] Table 7 additionally illustrates the coefficient of friction (CoF) measured through a tribometer as per ASTM G99 for example compositions 11 and 12. As seen in the table below, example compositions 11 and 12 generally display a lower CoF than comparatives 1-11, reducing the amount of wear on the fabric substrate adhered on an elastomeric body (such as a belt). Table 7: Example Coating Compositions 11 and 12 Properties Sample Average Initial Final z Damage CoF CoF CoF value Score

Claims

CLAIMS What is claimed is: 1. A coating composition for flexible substrates, comprising: a binder resin; a lubricating component comprising at least one of: lubricating filler particles comprising a wax having a melting point from 80^oC to 150^oC, as determined by ASTM D87; polyethylene having a melting point from 80^oC to 150^oC, as determined by ASTM D87; and a solvent.

2. The coating composition of claim 1, comprising a total amount of fluoropolymers of 0.1 wt.% or less, based on a total weight of the coating composition.

3. The coating composition of any one of claims 1-2, comprising the wax, and wherein the wax is at least one of a carnauba wax and a hydrocarbon wax.

4. The coating composition of any one of claims 1-3, comprising the polyethylene, and wherein the polyethylene has a melt viscosity less than 1,000 cp at 150 ^oC, as determined by ASTM D2196.

5. The coating composition of any one of claims 1-4, comprising the wax, and wherein the wax has a melt viscosity less than 300 cp at 150 ^oC, as determined by ASTM D2196.

6. The coating composition of any one of claims 1-5, comprising the polyethylene, and wherein the polyethylene has a melt viscosity less than 300 cp at 150 ^oC, as determined by ASTM D2196.

7. The coating composition of any one of claims 1-6, wherein the binder resin comprises at least one of: a hydroxyl functional polyester reactive with an isocyanate; and a polyurethane reactive with a carbodiimide.

8. The coating composition of any one of claims 1-7, wherein the lubricating component comprises from 1 to 20 wt.% of the coating composition, based on a total weight of the coating composition. 9. The coating composition of any one of claims 1-8, wherein a weight ratio of lubricating component to binder resin is from 0.1 to 0.

9, based on a total weight of lubricating component and binder resin.

10. The coating composition of claim 9, wherein the weight ratio of lubricating component to binder resin is from 0.25 to 0.66, based on the total weight of lubricating component and binder resin.

11. The coating composition of claim 10, wherein the weight ratio of lubricating component to binder resin is from 0.3 to 0.5, based on the total weight of lubricating component and binder resin.

12. The coating composition of any one of claims 1-11, wherein the lubricating component has an average particle size (D50) of 1 microns to 20 microns, as determined by dynamic light scattering ISO 13320-1.

13. A coated flexible substrate, comprising: a flexible substrate; and a non-continuous cured coating impregnated within the flexible substrate, comprising: a binder resin; and a lubricating component comprising at least one of: a wax having a melting point from 80^oC to 150^oC, as determined by ASTM D87; and polyethylene having a melting point from 80^oC to 150^oC, as determined by ASTM D87.

14. The coated flexible substrate of claim 13, wherein the coating comprises a total amount of fluoropolymers of 0.1 wt.% or less, based on a total weight of the coating.

15. The coated flexible substrate of any one of claims 13-14, comprising the wax, and wherein the wax is at least one of a carnauba wax and a hydrocarbon wax.

16. The coated flexible substrate of any one of claims 13-15, comprising the polyethylene, and wherein the polyethylene has a melt viscosity less than 1,000 cp at 150 ^oC, as determined by ASTM D2196.

17. The coated flexible substrate of any one of claims 13-16, wherein the binder resin comprises at least one of: a hydroxyl functional polyester reactive with an isocyanate; and a polyurethane reactive with a carbodiimide.

18. The coated flexible substrate of any one of claims 13-17, wherein the lubricating component comprises from 10 wt.% 60 wt. % of the cured coating, based on a total dry weight of the coating.

19. The coated flexible substrate of any one of claims 13-18, wherein a weight ratio of lubricating component to binder resin is from 0.1 to 0.9, based on a total weight of lubricating component and binder resin.

20. The coated flexible substrate of claim 19, wherein a weight ratio of lubricating component to binder resin is from 0.25 to 0.66, based on a total weight of lubricating component and binder resin.

21. The coated flexible substrate of claim 20, wherein the weight ratio of lubricating component to binder resin is from 0.3 to 0.5, based on a total weight of lubricating component and binder resin.

22. The coated flexible substrate of any of claims 13-21, wherein the substrate is a woven polymeric fabric material.

23. The coated flexible substrate of any one of claims 13-22, wherein the fabric material is fused to an endless polymeric belt.

24. The coated flexible substrate of any one of claims 13-23, wherein the flexible substrate has a first side and a second side, the first side configured to be permanently coupled to an elastomeric body and the second side configured to be impregnated with the coating composition such that the coating composition permeates less than 80% of the flexible substrate.