Abrasion-resistant and lubricious coating compositions for flexible substrates

Abstract

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

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 63 / 481,704, filed January 26, 2023, which provisional application incorporates by reference in its entirety.

[0002] SUMMARY OF THE DISCLOSURE The present disclosure relates to abrasion-resistant and lubricious coating compositions applied to flexible substrates such as power transmission belts. [Background technology]

[0003] Transmission belts in mechanical drive systems can experience a variety of forces that can cause wear. Coatings on transmission belts can increase resistance, prevent premature failure, and reduce noise. Traditional coatings for power transmission belts typically contain fluoropolymers, which may contain trace amounts of perfluoroalkyl substances (PFAS) and polyfluoroalkyl substances (PFAS). As fluoropolymer regulations raise increasing concerns about PFAS as components of substances and / or mixtures, it is desirable to provide coating compositions for flexible substrates, such as power transmission belts, that are substantially free of PFAS. Summary of the Invention

[0004] A coating composition for flexible substrates comprising a binder resin, a lubricating component in the form of lubricating filler particles of hydrocarbon wax and / or polyethylene, and a solvent, the coating composition being abrasion resistant and substantially free of fluoropolymers.

[0005] In one form thereof, the present disclosure provides a coating composition for a flexible substrate 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 of 80°C to 150°C as determined by ASTM D87, and a polyethylene having a melting point of 80°C to 150°C as determined by ASTM D87.

[0006] In another aspect, the present disclosure also provides a coated flexible substrate, the coated flexible substrate including a flexible substrate and a discontinuous coating impregnated into the flexible substrate, the coating including a binder resin and a lubricating component including at least one of a hydrocarbon wax having a melting point of 80°C to 150°C as measured by ASTM D87 and a polyethylene having a melting point of 80°C to 150°C as measured by ASTM D87.

[0007] These and other features and advantages of the present disclosure, as well as the manner in which they are achieved, will become more apparent, and the disclosure itself will be better understood, by reference to the following description of embodiments of the disclosure taken in conjunction with the accompanying drawings. These above-mentioned and other features of the present disclosure can be used in any combination or permutation. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a power transmission belt including a toothed elastomeric body having a coated fabric substrate adhered to a toothed surface. [Figure 2a] indicates a fabric substrate coated with a coating composition within Examples 1-10 described in this disclosure. [Figure 2b] indicates a fabric substrate coated with a known coating composition similar to Comparative Coatings 1-11 described in this disclosure. [Figure 3] FIG. 1 is a cross-sectional view of a portion of a coated fabric substrate according to Example 7.

[0009] Corresponding reference characters indicate corresponding parts throughout the several views. The illustrations presented herein illustrate exemplary embodiments of the present disclosure, and such illustrations should not be construed as limiting the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure demonstrates coating compositions that can be applied to flexible structures such as transmission belts. Additionally, the present disclosure provides lubricating coating compositions that are fluoropolymer-free.

[0011] I. Definition For purposes of the following detailed description, it will be understood that the present invention may assume various alternative variations and step sequences unless expressly specified to the contrary. Furthermore, except in any operating examples or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims should be understood in all instances to be modified by the term "about." For example, numerical ranges provided for ingredient weight percentages or amounts of ingredients added should be interpreted as modified by the term "about." Accordingly, unless indicated otherwise, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present disclosure. At the very least, the application of the doctrine of equivalents is not intended to limit the scope of the claims, and each numerical parameter should be construed at least in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0012] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible, however, any numerical value inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.

[0013] It should also be understood that any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, i.e., minimum values ​​of 1 or greater and maximum values ​​of 10 or less.

[0014] In this application, the use of the singular includes the plural and the use of the plural includes the singular unless otherwise stated. Additionally, the use of "or" means "or / and" unless otherwise stated, even though "and / or" may be expressly used in specific instances.

[0015] "Wax" is used herein to describe materials formed from mixtures of alkanes of various chain lengths and / or modified alkanes containing other functional groups such as esters and / or amines in the chain, which may exhibit phase change properties; waxes tend to be solid at room temperature (20°C), have melting points above about 40°C, and are able to absorb heat while exhibiting little volume change during melting.

[0016] "PFAS" is used herein to describe per- and polyfluorinated materials, including synthetic organofluorine compounds having multiple fluorine atoms attached to alkyl chains, e.g., perfluorinated monomers and oligomers such as perfluorooctanoic acid.

[0017] A "wet" coating composition is used herein to describe a liquid coating composition before it is cured.

[0018] A "dry" coating composition is used herein to describe the coating composition after it has cured.

[0019] "Transmission belt" or "timing belt" is used herein to describe a mechanical element comprising a loop of flexible material used to mechanically connect several rotating shafts.

[0020] "Flexible" as used in reference to a substrate that can be coated means capable of being bent or placed to yield.

[0021] "Discontinuous" as used in reference to a coating means that the coating is not necessarily a continuous film, but may have interruptions, voids, or gaps therein.

[0022] II. Coating Composition The present disclosure provides a PFAS-free coating for power transmission belts. The coating composition enhances the wear resistance and lubricity of the coated transmission belt. The coating composition may include a binder resin, a lubricating component, and a solvent.

[0023] A. Binder resin The binder resin provides adhesion to the substrate, improves mechanical properties such as elongation, and may be self-curing or cured with the aid of a curing agent. The binder resin may allow the coating to conform to the elongation of the coated belt during operation without cracking or disintegrating, or suffering from thermomechanical fatigue. The binder resin, referred to herein interchangeably as "binder," "resin binder," "binder resin," "base," or "binder system," may provide the majority of the coating of the present invention when applied to a substrate, depending on the amount of lubricating component desired.

[0024] The binder resin of the present disclosure may be a polymer binder containing a hydroxyl-functional polyester reacted with an isocyanate and a polyurethane reacted with a carbodiimide. Aqueous polycarbonate PUDs crosslinked with carbodiimides can produce coating films with higher melting points than aqueous polyesters, closer to the melting points of solvent-based polyurethanes. The binders of the present disclosure can be supplied as solvent- or water-based systems. Among the polymers suitable for use as binders in the coatings of the present disclosure, solvent-free aliphatic polyester polyurethane dispersions, aliphatic polycarbonate aqueous polyurethane dispersions, polycarbonate ester polyurethane dispersions, hydroxyl-bearing polyesters, acrylic polyols, aliphatic polyisocyanate resins, aliphatic polyisocyanates, VOC-free polycarbodiimides, and water-reducible activated multifunctional polycarbodiimides may be used.

[0025] The coating compositions provided by the present disclosure can contain, for example, 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%, where wt% is based on the total weight of the coating composition in a "wet" state.

[0026] The cured coating composition may contain 30 wt%, 35 wt%, 40 wt%, 50-60 wt%, 70 wt%, 80 wt%, 90 wt%, or any range including any two of these endpoints, such as 30-90 wt%, 35-80 wt%, 40-70 wt%, or 50-60 wt%, where wt% is based on the total weight of the coating composition in the "dry" state.

[0027] B. Lubricating ingredients Another component of the coating composition is a lubricating component, which acts to reduce friction between the surface of the coated substrate, such as a coated transmission belt, and another surface, such as a mechanical gear.

[0028] The coating compositions of the present disclosure may include a lubricating component that is an organic polymer made in the absence of fluorine-carbon bonds.

[0029] The lubricating component may be a wax that is solid at room temperature (20°C) and has a melting point of 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, for example, 80°C to 150°C, 90°C to 140°C, 100°C to 130°C, or 110°C to 120°C.

[0030] Such waxes include hydrocarbon waxes, ethylene bisstearylamide (EBS), alkane waxes, amide waxes, polyethylene waxes, carnauba wax, and any combination thereof.

[0031] Carnauba wax is a natural wax obtained from the leaves of the carnauba palm, native to northeastern Brazil. It contains aliphatic esters, diesters, 4-hydroxycinnamic acid, w-hydroxycarboxylic acids, and higher alcohols.

[0032] The carnauba wax may comprise particles having a median particle diameter (D50) of 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 measurements using Mie scattering and Fraunhofer diffraction methods as specified in ISO 13320-1.

[0033] The lubricating component may contain fine particles having a median diameter (D50) of 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. The median diameter is measured by dynamic light scattering using Mie scattering and Fraunhofer diffraction methods in accordance with ISO 13320-1.

[0034] The coating composition according to the present disclosure may contain the lubricating component in an amount of, for example, 1% by weight, 2% by weight, 5% to 10% by weight, 15% by weight, 20% by weight, or any range including any two of these values ​​as endpoints, such as 1% to 20% by weight, 2% to 15% by weight, or 5% to 10% by weight, where % by weight is the percentage of the total coating composition in a "wet" state.

[0035] In the coating composition according to the present disclosure, the mass ratio of the lubricating component to the sum of the binder resin in a dry state and the lubricating component in a dry state may be 0.1, 0.25, 0.3 to 0.5, 0.66, 0.9, or any range including any two of these values ​​as endpoints, for example, 0.1 to 0.9, 0.25 to 0.66, or 0.3 to 0.5.

[0036] The lubricating component may be contained in the cured coating composition in an amount of, for example, 10% by mass, 20% by mass, 30% to 40% by mass, 50% by mass, 60% by mass, or any range including any two of these values ​​as endpoints, such as 10% to 60% by mass, 20% to 50% by mass, or 30% to 40% by mass. Here, % by mass is the proportion relative to the total coating composition in the "dry state."

[0037] C. Solvent The coating composition may include one or more solvents. Exemplary solvents include water, alcohols (e.g., C1-C8 alcohols, such as methanol, ethanol, isopropanol, and t-butanol), C2-C8 ketones (e.g., acetone), C2-C20 ethers (e.g., dipropylene glycol methyl ether), and protic or aprotic solvents such as dimethyl sulfoxide and N-methylpyrrolidone.

[0038] The solvent may comprise 15%, 20%, 25%, 30% to 35%, 40%, 45%, 50% by weight, or any value encompassed by these endpoints, for example, 15% to 50%, 20% to 45%, 25% to 40%, or 30% to 35% by weight, based on the total weight of the "wet" coating composition.

[0039] After the coating is applied and cured, the overall coating composition may be substantially free of solvent, that is, the solvent may comprise 0%, 0.1%, 0.15%, 0.2%, or any value encompassed by these endpoints, such as 0% to 0.2%, or 0.1% to 0.15%, by weight of the total weight of the "dry" coating composition.

[0040] D. Additives In addition to the above-mentioned components, additives may be present in the coating composition of the present disclosure. These additives may include components for improving stability, application, and aesthetics. Additives that may be included in the coating composition of the present invention include defoamers, thickeners, surface wetting agents or surfactants, color pastes, and pigments.

[0041] The total amount of such additives may be 0%, 5%, 10% to 20%, 30%, 40% by weight, or any other combination of ranges using these endpoints, e.g., 0% to 40%, 5% to 30%, or 10% to 20% by weight, based on the total weight of the coating composition "wet" before coating on a substrate and subsequent curing.

[0042] After coating and curing, the additives may be present in an amount of 0%, 2%, 4% to 6%, 8%, 10%, 15% by weight, or any range including any two of these values ​​as endpoints, based on the total weight of the coating composition in the "dry state", for example, 0% to 10%, 2% to 8%, or 4% to 6% by weight.

[0043] III. Methods for Coating Flexible Substrates The coating compositions of the present disclosure can be applied to substrates such as woven polymeric fabric materials. Suitable substrates may be woven fabrics such as polyester, polyamide, aramid, cotton, or other polymeric materials.

[0044] A. Applications To apply the coating composition of the present disclosure, the coating composition may be deposited onto a textile substrate via a variety of methods. Application methods may include dipping, spraying, knife-on-air, and knife-over-roll coating. Once applied, the coating composition impregnates the textile substrate so that the coating composition is within the textile substrate. The coating composition may penetrate at least 20-30% into the weave of the textile substrate, based on the thickness of the textile substrate, which may be determined by any imaging method, such as using a scanning electron microscope as in Example 3 below.

[0045] i.Immersion To coat a textile substrate using the dipping process, the textile substrate is dipped into a reservoir of the coating composition such that the textile substrate is impregnated with the coating composition, and the coated substrate is then removed from the reservoir and placed for curing.

[0046] ii. Spraying Spraying is another form of application that can be used to apply the coating compositions of the present application. Spraying involves using an atomized spray of coating composition particles or droplets to deposit the coating composition onto a substrate. The substrate may be passed under the spray or otherwise exposed to the coating composition spray for a predetermined time to deposit a desired amount of coating composition.

[0047] iii. Knife on Air Knife-on-air or air knife coating is a process for applying a predetermined amount of coating composition to a substrate. The process involves placing the substrate on a series of rollers that move the substrate under a mechanism for depositing the coating composition, such as a reservoir that drips the coating composition onto the substrate. Excessive amounts of coating composition may be deposited on the substrate. To remove excess coating, the coated substrate is passed under an air jet that blows the excess coating off the substrate. The angle of the air jet relative to the substrate and the air velocity are calculated to leave a predetermined amount of coating composition on the substrate. The coating composition of the present disclosure can be applied to a fabric substrate using the knife-on-air method of application.

[0048] iv. Knife over roller Another process for applying the coating composition of the present disclosure to a fabric substrate is knife-over-roller or gap coating. Similar to the knife-on-air process described above, this process involves placing the substrate on a series of rollers that pass under a mechanism that deposits the coating composition. The amount of coating composition deposited may be more than necessary to coat the substrate. To remove excess coating, the coated substrate passes through a gap created between the substrate and a knife positioned above the substrate. The knife's positioning is predetermined to scrape off excess coating and leave only the desired amount of coating on the substrate as it passes through the gap.

[0049] B. Hardening Once the textile substrate is coated with the coating composition, the coating is cured or dried at temperatures of 130°C, 140°C, 145°C to 150°C, 160°C, 170°C, or any other combination of ranges using these endpoints, e.g., 130°C to 170°C, 140°C to 160°C, or 145°C to 150°C. The coating composition may be cured at the aforementioned temperatures for 2 minutes, 6 minutes, 10 minutes, 14 minutes, 18 minutes, 20 minutes, or any other combination of ranges using these endpoints, e.g., 2 minutes to 20 minutes, 6 minutes to 18 minutes, or 10 minutes to 14 minutes. If the coating composition contains a solvent, the coating composition may not be cured and instead may be fully cured during the vulcanization process.

[0050] C. Vulcanization process Once the textile substrate is coated, it can be applied to an elastomeric body, such as an endless polymer belt, and permanently bonded to the elastomeric body by vulcanization. During the vulcanization process, the coated textile substrate is laminated onto the elastomeric body using high pressure and temperature, such as 170°C / 20 minutes. The high temperature and pressure may not soften the coating composition. The resulting product is a textile substrate bonded to an elastomeric body, with the outer layer of the textile substrate containing a binder resin and a lubricant that permeates the textile substrate, providing greater overall resistance to pulley wear than a similar structure without the coating composition.

[0051] As seen in FIG. 1 , the power transmission belt 10 includes a fabric substrate 30 adhered at 20 to the surface of an elastomeric body 15. The coating composition may be impregnated into the fabric substrate 30, and the depth of impregnation (shown at 32) may be 35% or more, 50% or more, 65% or more, 75% or more, or 90% or more of the total thickness of the fabric substrate 30.

[0052] IV. Coating Properties The coating compositions of the present disclosure exhibit a variety of properties, including high melting points, low melt flow viscosities, and being fluoropolymer-free.

[0053] A. Abrasion resistance During gear or pulley operation, belts or other elastomeric bodies vulcanized onto a textile substrate can experience wear and tear due to friction between the belt and the gear / pulley. The coating compositions described herein improve the durability and abrasion resistance of belts with coated textile substrates. This improved durability can extend the life and use of the belt and reduce the risk of failure.

[0054] B. Melt viscosity The melt viscosity of a polymer at a given temperature is a measure of the rate at which chains can move relative to one another, such as the ease of rotation about the polymer's backbone bonds. Polymers with less flexible chains are more viscous in the melting range than polymers with more flexible chains.

[0055] The coating composition according to the present disclosure was measured in accordance with ASTM D2196 using a rotational rheometer (60 mm plate-plate configuration, 1 mm gap, shear rate 5 s -1 The melt flow viscosity at 150°C measured using a fluororesin (FRP) may be less than 1000 cP, less than 800 cP, less than 600 cP to less than 400 cP, less than 200 cP, less than 100 cP, or more than 10 cP, or may be any range including any two of these values ​​as endpoints.

[0056] D. Fluoropolymer-free Due to the imposition of PFAS-containing fluoropolymers, there is a concern about having a PFAS-free coating composition. The coating composition of the present invention may lack fluoropolymers, or the coating composition may be free of fluoropolymers. Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are fluorine-containing compounds, including perfluoroalkyl acids (PFAA), such as perfluorooctanoic acid (PFOA) and / or perfluorooctane sulfonate (PFOS). The coating composition of the present disclosure may be essentially, substantially, or completely free of PFAS.

[0057] Essentially PFAS-free means that the coating compositions of the present disclosure contain no more than 1 wt% of per- and polyfluorinated alkyl compounds based on the total weight of the coating composition and / or have a total PFAS content of less than 1 ppm based on the total weight of the coating. Substantially PFAS-free means that the coating compositions of the present disclosure contain no more than 0.1 wt% of per- and polyfluorinated alkyl compounds based on the total weight of the coating composition and / or have a total PFAS content of less than 0.1 ppm based on the total weight of the coating. Completely PFAS-free means that the coating compositions of the present disclosure contain no more than 0.01 wt% of per- and polyfluorinated alkyl compounds based on the total weight of the coating composition and / or have a total PFAS content of less than 0.01 ppm based on the total weight of the coating. [Example]

[0058] Aspects of the present disclosure are further illustrated with 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.

[0059] Compositions were formulated as described below in accordance with the coating compositions of the present disclosure. The coating compositions were applied to textile substrates and tested for impregnating coating properties, with the following results:

[0060] Example 1 Exemplary Coating Compositions Referring to Table 1, Comparative Examples 1-11 were prepared using the following known coating compositions: Additionally, exemplary compositions 1-4 of the present disclosure were formulated using the following compositions:

[0061] Table 1 shows the compositions of Comparative Examples 1-2 and Example Compositions 1-4, as described below. [Table 1]

[0062] Example 2 Testing of Exemplary Coating Compositions Comparative Compositions 1-11 and Exemplary Compositions 1-5 were prepared by mixing the liquid ingredients and stirring or processing in a mill until the powders were properly dispersed and a homogeneous coating was formed without obvious aggregates or lumps, then applied to a textile substrate by the knife-on-air method and tested to determine the coefficient of friction of the textile substrate coated with the coating composition.

[0063] Table A shows the test parameters for each of the following tests: [Table 2]

[0064] Damage scores were measured, for example, for Compositions 1-4 and Comparative Examples 1-11. Damage scores are measured relative to an image standard on a calibrated scale and are an indication of actual coating survival after tribological testing according to ASTM G99. Table 2 shows examples of coated substrates after exposure to tribological testing exhibiting various damage scores. [Table 3-1] [Table 3-2]

[0065] Table 3, for example, shows the coefficient of friction (CoF) measured via a tribometer according to ASTM G99 for Compositions 1-4 and Comparative Examples 1-11. As can be seen in the table below, exemplary Compositions 1-4 generally exhibit a lower CoF than Comparative Examples 1-11, reducing the amount of wear on a fabric substrate adhered to an elastomeric body (such as a belt). [Table 4]

[0066] Figures 2a and 2b correlate with the results in Table 2. Table 2 and Figures 2a and 2b demonstrate that textile substrates coated with coating compositions of the present disclosure exhibit superior abrasion resistance than textile substrates coated with known coating compositions, such as the comparative examples.

[0067] Figure 2a shows a textile substrate coated with a coating composition within the range of coating formulations of Examples 1-10 described in the present disclosure 100a. Figure 2b shows a textile substrate coated with a known coating composition 100b, as well as a comparative coating disclosed herein. Each coated textile substrate shown in Figures 2a and 2b was subjected to a linear reciprocating abrasion test at a constant temperature of 170°C. The reciprocating abrasion at 170°C simulates the service conditions the coated textile substrate would experience when combined with an elastic body, such as a belt, sliding against a pulley or gear.

[0068] After 500 strokes of reciprocating abrasion, as seen in Figure 2a, the fabric substrate coated with a coating composition similar to the exemplary coating composition of the present disclosure 100a had no visible marks. As seen in Figure 2b, the fabric substrate coated with the comparative coating composition 100b underwent significant abrasion 140. This result is supported by the values ​​in Table 2. The average coefficients of friction for Examples 1-4 ranged from 0.183 to 0.248, while the average coefficients of friction for Comparative Examples 1-11 ranged from 0.230 to 0.609. Due to the lower CoF, the fabric substrate coated with the coating composition of the present disclosure exhibited improved abrasion resistance and no visible damage to the substrate surface.

[0069] Example 3 Cross section of a fabric substrate coated with a coating composition 3 shows a cross-sectional image 200 of an elastomeric body 210 having a textile substrate 220 coated with a coating composition 230 of the present disclosure. The image 200 was obtained using a scanning electron microscope with an electron acceleration of 5-20 kV, a working distance of between 10-20 mm, and a backscattered electron detector at 50x magnification.

[0070] The coating composition 230, which includes FeO as a marker and appears as small black dots in Figure 3, was formulated using the formulation of Example 7 described below. The coated textile substrate 220 is adhered to the elastomeric body 210, which forms the fiberglass tensile cord layer 215. The concentration and extent of penetration of the coating composition 230 into the textile substrate 220 can be seen through the marker. The depth of impregnation 232 is greater than 50% of the total thickness of the textile substrate 220.

[0071] Example 4 Exemplary Coating Compositions Table 4 shows the compositions of Comparative Example 1 and Examples 5-9. The fill factor is a measure of the weight percent of lubricant in the total weight of binder and lubricant. When the fill factor exceeds 10% of the weight of lubricant relative to the total weight of binder and lubricant, all tribological properties increase significantly, resulting in better damage scores and lower CoF (see Table 4). [Table 5]

[0072] Example 5 Exemplary Coating Composition Properties Table 5 shows the amount of lubricant, binder resin, and percent lubricant on the binder for Comparative Example 1 and Examples 5-11. The CoF of each of Comparative Example 1 and Examples 5-11 was tested using ASTM G99. Examples 5-11 were shown to have a lower CoF than the Comparative Example, which improves wear resistance from the use of a fabric substrate vulcanized on an elastomeric body against a pulley or gear. [Table 6]

[0073] As shown in Examples 1-5, exemplary compositions 1-9, when applied to fabric substrates, exhibit improved abrasion resistance over known comparative coating compositions. Due to the improved abrasion resistance, the coating compositions of the present disclosure may extend the life of coated fabric substrates adhered to elastomeric bodies used in transmission belt assemblies.

[0074] While particular embodiments of the present invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that many changes in the details of the invention can 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 present 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 the disclosure pertains and which fall within the scope of the appended claims.

[0075] Example 6 Exemplary Coating Composition - Carnauba Wax Referring to Table 6, exemplary compositions 11 and 12 of the present disclosure were formulated using the following compositions: [Table 7]

[0076] Table 7 shows the properties tested for Examples 11 and 12 using the test conditions previously set forth in Table A. Damage scores were measured for Example Compositions 11 and 12. The damage score was measured on a calibrated scale by comparison with image standards (Table 2) and is an indication of actual coating survival after tribological testing according to ASTM G99. Table 7 shows examples of coated substrates after exposure to tribological testing showing various damage scores.

[0077] Table 7 further shows the coefficient of friction (CoF) measured via a tribometer according to ASTM G99, for example, compositions 11 and 12. As can be seen in the table below, exemplary compositions 11 and 12 generally exhibit a lower CoF than comparative examples 1-11, reducing the amount of wear on a fabric substrate adhered to an elastomeric body (such as a belt). [Table 8]

Claims

1. 1. A coating composition for a flexible substrate, comprising: A binder resin, a lubricating component comprising at least one of lubricating filler particles comprising a wax having a melting point of 80°C to 150°C as measured by ASTM D87 and a polyethylene having a melting point of 80°C to 150°C as measured by ASTM D87; Solvent and 1. A coating composition comprising:

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

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

4. 4. The coating composition of any one of claims 1 to 3, comprising the polyethylene, the polyethylene having a melt viscosity of less than 1,000 cp at 150°C as measured by ASTM D2196.

5. 5. The coating composition of any one of claims 1 to 4, comprising said wax, said wax having a melt viscosity of less than 300 cp at 150°C as measured by ASTM D2196.

6. 6. The coating composition of any one of claims 1 to 5, comprising said polyethylene, said polyethylene having a melt viscosity of less than 300 cp at 150°C as measured by ASTM D2196.

7. The binder resin is The coating composition of any one of claims 1 to 6, comprising at least one of an isocyanate-reactive hydroxyl-functional polyester and a carbodiimide-reactive polyurethane.

8. The coating composition of any one of claims 1 to 7, wherein the lubricating component comprises 1 to 20 wt% of the coating composition, based on the total weight of the coating composition.

9. 9. The coating composition according to claim 1, wherein the weight ratio of the lubricating component to the binder resin is 0.1 to 0.9, based on the total weight of the lubricating component and the binder resin.

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

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

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

13. A coated flexible substrate, comprising: a flexible substrate; a discontinuous cured coating infiltrated within said flexible substrate, A binder resin, a lubricating component comprising at least one of a wax having a melting point of 80°C to 150°C as measured by ASTM D87 and a polyethylene having a melting point of 80°C to 150°C as measured by ASTM D87; a discontinuous cured coating comprising: A coated flexible substrate comprising:

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

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

16. 16. The coated flexible substrate of any one of claims 13 to 15, comprising polyethylene, wherein the polyethylene has a melt viscosity of less than 1,000 cp at 150°C as measured by ASTM D2196.

17. The binder resin is The coated flexible substrate of any one of claims 13 to 16, comprising at least one of an isocyanate-reactive hydroxyl-functional polyester and a carbodiimide-reactive polyurethane.

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

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

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

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

22. The coated flexible substrate of any one of claims 13 to 21, wherein the substrate is a woven polymeric textile material.

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

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

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