Wear resistant and lubricious coating composition for flexible substrates

Abstract

The present disclosure provides a coating composition for a flexible substrate 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. The coating composition is wear resistant and substantially free of fluoropolymers.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] 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 herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a wear-resistant, lubricating coating composition for coating flexible substrates, such as drive belts. Background Art

[0004] Drive belts within mechanical transmission systems may be subject to a variety of forces that can cause wear and tear. Coatings can be applied to drive belts to increase resistance, prevent premature failure, and suppress noise. Known drive belt coatings typically contain fluoropolymers that may potentially contain small amounts of per / polyfluoroalkyl substances (PFAS). Fluoropolymer regulatory environments are increasingly concerned about PFAS as a component of substances and / or mixtures, and therefore, there is a need to provide a coating composition for flexible substrates (e.g., drive belts) that is substantially free of PFAS. Summary of the Invention

[0005] The present disclosure provides a coating composition for a flexible substrate, the coating composition 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 is wear-resistant and substantially free of fluoropolymers.

[0006] In one form thereof, the present disclosure provides a coating composition for a flexible substrate, the coating composition 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 polyethylene having a melting point of 80°C to 150°C, as determined by ASTM D87.

[0007] In another form of the present disclosure, the present disclosure also provides a coated flexible substrate comprising: a flexible substrate; and a discontinuous cured coating impregnated in the flexible substrate, the discontinuous cured coating comprising: a binder resin; a lubricating component comprising at least one of the following: a hydrocarbon wax having a melting point of 80°C to 150°C, as determined by ASTM D87; and polyethylene having a melting point of 80°C to 150°C, as determined by ASTM D87. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] By referring to the following description in conjunction with the accompanying drawings, the above and other features and advantages of the present disclosure and the manner in which they are obtained will become more apparent, and the present disclosure itself will be better understood. The above and other features of the present disclosure may be used in any combination or arrangement.

[0009] Figure 1 is a cross-sectional view of a power transmission belt including a toothed elastomeric body with a coated fabric substrate adhered to the toothed surface;

[0010] Figure 2a Shown are fabric substrates coated with coating compositions within the range of Examples 1-10 described in this disclosure;

[0011] Figure 2b showing a fabric substrate coated with a known coating composition similar to Comparative Coatings 1-11 described in this disclosure; and

[0012] Figure 3 is a cross-sectional view of a portion of a coated textile substrate according to Example 7.

[0013] Corresponding reference characters indicate corresponding parts throughout the several views.The examples set out herein illustrate the disclosure, and such examples should not be construed as limiting the scope of the disclosure in any way. DETAILED DESCRIPTION

[0014] The present disclosure provides a coating composition that can be applied to a flexible structure (eg, a transmission belt). In addition, the present disclosure also provides a lubricating coating composition that does not contain a fluoropolymer.

[0015] I. Definition

[0016] For the purpose of the following detailed description, it should be understood that the present disclosure can take various alternative changes and step orders, unless expressly indicated to the contrary. In addition, except in any operating examples, or where otherwise indicated, all numbers used in the specification and claims to represent, for example, the quantity of ingredients should be understood to be modified by the term "about" in all cases. For example, the numerical range provided for the weight percentage of a component or the amount of an added component should be interpreted as being modified by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that can vary according to the desired properties to be obtained by the present disclosure. At least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in accordance with the number of reported significant figures and by applying ordinary rounding techniques.

[0017] 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 deviation found in their respective testing measurements.

[0018] Furthermore, it should be understood that any numerical range recited herein is intended to encompass all subranges therein. For example, a range of "1 to 10" is intended to include all subranges from the recited minimum value of 1 to the recited maximum value of 10 (and including both the minimum and maximum values), i.e., having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

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

[0020] "Wax" is used herein to describe materials formed from mixtures of alkanes of various chain lengths and / or modified alkanes that also include other functional groups in the chain, such as esters and / or amines, and that can exhibit phase change properties, wherein waxes tend to be solid at room temperature (20°C), have melting points above about 40°C, and are able to absorb heat while experiencing little change in volume during melting.

[0021] "PFAS" is used herein to describe perfluorinated and polyfluorinated substances, including synthetic organofluorine compounds with multiple fluorine atoms attached to an alkyl chain, for example, perfluorinated monomers and oligomers, such as perfluorooctanoic acid.

[0022] A "wet" coating composition is used herein to describe a liquid coating composition prior to curing.

[0023] "Dry" coating composition is used herein to describe the coating composition after curing.

[0024] The terms "drive belt" or "timing belt" are used herein to describe a mechanical element that includes a loop of flexible material used to mechanically connect multiple rotating shafts.

[0025] "Flexible" as used in connection with substrates that can be coated means capable of bending or tending to yield.

[0026] "Discontinuous" as used in connection with a coating means that the coating is not necessarily a continuous film, but that interruptions, voids, or gaps may exist therein.

[0027] II. Coating composition

[0028] The present disclosure provides a PFAS-free coating for a transmission belt. The coating composition can improve the wear resistance and lubricity of the coated transmission belt. The coating composition can include a binder resin, a lubricating component, and a solvent.

[0029] A. Binder resin

[0030] The binder resin provides adhesion to the substrate and improves mechanical properties (such as elongation) and can be self-curing or cured with the help of a curing agent. The binder resin allows the coating to follow the elongation of the coated belt during operation without cracking or peeling or suffering from thermomechanical fatigue. The binder resin is interchangeably referred to herein as 'binder', 'resin binder' or 'binder resin', 'base' or 'binder system', and depending on the amount of lubricating component required, when applied to the substrate, the binder resin can provide the bulk of the coating of the present invention.

[0031] The binder resin of the present disclosure can be a polymer binder comprising a hydroxyl-functional polyester reacted with an isocyanate and a polyurethane reacted with a carbodiimide. Water-based polycarbonate PUD cross-linked with carbodiimide can produce a coating film having a melting point higher than that of the water-based polyester, which has a melting point closer to that of the solvent-based polyurethane. The binder of the present disclosure can be supplied in the form of a solvent-based or water-based system. Among the polymers suitable for use as binders in the coating of the present disclosure, solvent-free aliphatic polyester polyurethane dispersions, aliphatic polycarbonate waterborne polyurethane dispersions, polycarbonate polyurethane dispersions, hydroxyl-containing polyesters, acrylic polyols, aliphatic polyisocyanate resins, aliphatic polyisocyanates, VOC-free polycarbodiimides, and water-dilutable activated multifunctional polycarbodiimides can be used.

[0032] The coating compositions provided by the present disclosure can include a binder resin in an amount of, 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.%, wherein the weight percentages are based on the total weight of the "wet" coating composition.

[0033] The binder resin can be present in the cured coating composition in an amount of 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.%, where the weight percentages are based on the total weight of the "dry" coating composition.

[0034] B. Lubricating components

[0035] Another component of the coating composition is a lubricating component. The lubricating component is used to reduce the friction between the surface of the coated substrate (such as a coated drive belt) and another surface (such as a mechanical gear).

[0036] The coating composition of the present disclosure may include a lubricating component that is an organic polymer produced in the absence of fluorine-carbon bonds.

[0037] 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, such as 80°C to 150°C, 90°C to 140°C, 100°C to 130°C, or 110°C to 120°C.

[0038] Such waxes as described may be hydrocarbon waxes, ethylene bisstearamide (EBS), alkane waxes, amide waxes, polyethylene waxes, carnauba waxes, and any combination thereof.

[0039] Carnauba wax is a natural wax that comes from the leaves of the carnauba palm tree, a tree native to northeastern Brazil. Carnauba wax contains fatty esters, diesters, 4-hydroxycinnamic acid, w-hydroxycarboxylic acids, and fatty alcohols.

[0040] The carnauba wax may comprise particles having a median diameter or 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 measured by Mie scattering and Fraunhofer diffraction techniques according to ISO 13320-1 practice.

[0041] The lubricating component may comprise small particles having a median diameter or 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, as determined by dynamic light scattering measured by Mie scattering and Fraunhofer diffraction techniques in accordance with ISO 13320-1 practice.

[0042] The coating compositions provided by the present disclosure can include a lubricating component in a weight percentage of, for example, 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 percentages are based on the total weight of the "wet" coating composition.

[0043] The weight ratio of the lubricating component to the total amount of the dry binder resin and the dry lubricant in the coating composition of the present disclosure can 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, such as 0.1 to 0.9, 0.25 to 0.66, or 0.3 to 0.5.

[0044] The lubricating component can be present in the cured coating composition in an amount of 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.%, where the weight percentages are based on the total weight of the "dry" coating composition.

[0045] C. solvent

[0046] The coating composition may include one or more solvents. Exemplary solvents include water, alcohols (such as C1-C8 alcohols, including methanol, ethanol, isopropyl alcohol and tert-butyl alcohol), C2-C8 ketones (including acetone), C2-C20 ethers (including dipropylene glycol methyl ether) and other protic or aprotic solvents, such as dimethyl sulfoxide or N-methylpyrrolidone.

[0047] The solvent can be present in the composition in an amount of 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.%, where the weight percentages are based on the total weight of the "wet" coating composition.

[0048] After the coating is applied and cured, the total coating composition can be substantially free of solvent. In other words, the solvent can be present in the composition in an amount of 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.%), where the weight percentages are based on the total weight of the "dry" coating composition.

[0049] D. additive

[0050] In addition to the above components, additives may also be present in the coating compositions of the present invention. These additives may include components for improving stability, applicability, and aesthetics. Additives that may be included in the coating compositions of the present invention may include defoamers, thickeners, surface wetting agents or surfactants, coloring pastes, and pigments.

[0051] The total amount of such additives can be 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.%, based on the "wet" weight of the coating composition prior to subsequent curing on the substrate, where the weight percentages are based on the total weight of the "wet" coating composition.

[0052] After the coating is applied and cured, the additives can 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.%, where the weight percentages are based on the total weight of the "dry" coating composition.

[0053] III. Method for coating flexible substrates

[0054] The coating compositions of the present disclosure can be applied to a substrate, such as a woven polymeric fabric material. Suitable substrates can be fabrics such as polyester, polyamide, aramid, cotton or other polymeric materials.

[0055] A. Imposition

[0056] To apply the coating composition of the present disclosure, the coating composition can be deposited onto the fabric substrate by a variety of methods. Application methods may include coating by dipping, spraying, air knife, and knife-and-roll. Once applied, the coating composition impregnates the fabric substrate, such that the coating composition is within the fabric substrate. Based on the thickness of the fabric substrate, the coating composition may penetrate at least 20-30% into the weave of the fabric substrate, as determined by any imaging method, such as using a scanning electron microscope, as described in Example 3 below.

[0057] i. Dip coating

[0058] To coat a fabric substrate using a dip coating process, the fabric substrate is dipped into a reservoir of the coating composition so that the fabric substrate is impregnated with the coating composition. The coated substrate is then removed from the reservoir and set aside to cure.

[0059] ii. spraying

[0060] Spraying is another application method that can be used to apply the coating composition of the present application. Spraying involves depositing the coating composition onto a substrate using a spray of particles or droplets of the coating composition. The substrate can be passed under the spray or otherwise exposed to the spray of the coating composition for a predetermined amount of time to deposit the desired amount of the coating composition.

[0061] iii. Air Knife

[0062] Air knife 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 coating composition may be deposited onto the substrate. To remove excess coating, the coated substrate is passed under an air jet that blows off excess coating from the substrate. The angle at which the air jet is positioned relative to the substrate and the air velocity are calculated so that the predetermined amount of coating composition remains on the substrate. The coating composition of the present disclosure can be applied to a textile substrate using an air knife application method.

[0063] iv. knife roller

[0064] Another process for applying the coating compositions of the present disclosure to textile substrates is knife-and-roll or gap coating. This process involves placing the substrate on a series of rollers that pass beneath a mechanism that deposits the coating composition, similar to the air knife process described above. The amount of coating composition deposited may exceed the amount required to coat the substrate. To remove the excess coating, the coated substrate is passed through a gap created between the substrate and a scraper positioned above the substrate. The scraper is positioned to remove the excess coating and leave only the desired amount of coating on the substrate as it passes through the gap.

[0065] B. Curing

[0066] Once the textile substrate has been coated with the coating composition, the coating is cured or dried at a temperature of 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 can be cured at the aforementioned temperatures for 2 minutes, 6 minutes, 10 minutes, 14 minutes, 18 minutes, 20 minutes, or any other range combination using these endpoints, such as 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 cure, but rather fully cure during the vulcanization process.

[0067] C. Vulcanization process

[0068] Once the fabric substrate has been coated, the fabric substrate 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, high pressure and high temperature (such as 170°C / 20 minutes) are used to laminate the coated fabric substrate to the elastomeric body. The high temperature and high pressure may not soften the coating composition. The resulting product is a fabric substrate adhered to the elastomeric body, wherein the outer layer of the fabric substrate includes an adhesive resin and a lubricant that penetrate the fabric substrate, making the entire structure more durable against wear from the pulley than a similar structure without the coating composition.

[0069] like Figure 1 As shown, the drive belt 10 includes a fabric substrate 30 adhered to the surface of the elastomeric body 15 at 20. The coating composition can be impregnated into the fabric substrate 30, wherein the impregnation depth shown at 32 can be greater than 35%, greater than 50%, greater than 65%, greater than 75%, or greater than 90% of the total thickness of the fabric substrate 30.

[0070] IV. Coating characteristics

[0071] The coating compositions of the present disclosure exhibit various properties, including a high melting point, low melt flow viscosity, and the absence of fluoropolymers.

[0072] A. wear resistance

[0073] During operation of a gear or pulley, a belt or other elastomeric body vulcanized to a fabric substrate may experience wear and tear due to friction between the belt and the gear / pulley. The coating compositions described in this disclosure improve the durability and wear resistance of belts having a coated fabric substrate. This increased durability can increase the life and use of the belt and reduce the risk of failure.

[0074] B. melt viscosity

[0075] The melt viscosity of a polymer at a given temperature is a measure of the rate at which the chains can move relative to each other, such as how easily they can rotate about the polymer's backbone bonds. Polymers with less flexible chains are more viscous within their melting range than polymers with less flexible chains.

[0076] According to ASTM D2196, a plate with a 60 mm plate-to-plate geometry, a 1 mm gap and a flow rate of 5 s was used. -1 The coating composition of the present invention may have a melt flow viscosity at 150° C. of 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 greater than 10 cP, or any range including any two of these values ​​as endpoints.

[0077] D. Does not contain fluoropolymers

[0078] With the increasing regulation of PFAS (including fluoropolymers), there has been interest in coating compositions that are PFAS-free. The present coating composition can lack a fluoropolymer, wherein the coating composition is fluoropolymer-free. Per- and polyfluoroalkyl substances (PFAS) are fluorinated compounds, including perfluoroalkyl acids (PFAAs), such as perfluorooctanoic acid (PFOA) and / or perfluorooctane sulfonate (PFOS). The coating compositions of the present disclosure can be substantially, essentially, or completely free of PFAS.

[0079] Substantially free of PFAS means that the coating composition of the present disclosure comprises a total amount of 1 wt.% or less of perfluorinated and polyfluorinated alkyl compounds, based on the total weight of the coating composition, and / or the total content of PFAS in the coating composition of the present disclosure is less than 1 ppm, based on the total weight of the coating. Essentially free of PFAS means that the coating composition of the present disclosure comprises a total amount of 0.1 wt.% or less of perfluorinated and polyfluorinated alkyl compounds, based on the total weight of the coating composition, and / or the total content of PFAS in the coating composition of the present disclosure is less than 0.1 ppm, based on the total weight of the coating. Completely free of PFAS means that the coating composition of the present disclosure comprises a total amount of 0.01 wt.% or less of perfluorinated and polyfluorinated alkyl compounds, based on the total weight of the coating, and / or the total content of PFAS in the coating composition of the present disclosure is less than 0.01 ppm, based on the total weight of the coating.

[0080] Examples

[0081] 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, can be made without departing from the scope of the present disclosure.

[0082] The coating compositions according to the present disclosure were formulated as follows: The coating compositions were applied to textile substrates and the properties of the impregnated coatings were tested to obtain the following results.

[0083] Example 1

[0084] Exemplary coating compositions

[0085] Referring to Table 1, Comparatives (Comp.) 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.

[0086] Table 1 lists the compositions of Comparative Compositions 1-2 and Exemplary Compositions 1-4 as described below.

[0087] Table 1: Comparative and exemplary coating compositions

[0088]

[0089] Example 2

[0090] Testing of Exemplary Coating Compositions

[0091] Comparative compositions 1-11 and exemplary compositions 1-5 were prepared by mixing the liquid ingredients and stirring the powders in a grinder or processing the powders through a grinder until properly dispersed and until a uniform coating free of noticeable aggregates and lumps was obtained; they were then applied to a textile substrate by an air knife method and tested to determine the coefficient of friction of the textile substrates coated with the coating compositions.

[0092] Table A shows the test parameters for each of the following tests.

[0093] Table A: Test parameters

[0094] Time(s) load RPM Disk radius Linear speed (m / s) 72,000 20 600 20 1.256

[0095] Damage scores were measured for Exemplary Compositions 1-4 and Comparatives 1-11. Damage scores are measured by comparison to an image standard in a calibrated ruler and are an indicator of actual coating survival after tribological testing according to ASTM G99. Table 2 shows examples of coated substrates exhibiting different damage scores after exposure to tribological testing.

[0096] Table 2: Injury Scores

[0097]

[0098]

[0099] Table 3 shows the coefficient of friction (CoF) of Exemplary Compositions 1-4 and Comparatives 1-11 as measured by a tribometer according to ASTM G99. As shown in the table below, Exemplary Compositions 1-4 generally exhibit lower CoF than Comparatives 1-11, thereby reducing the amount of wear on a fabric substrate adhered to an elastomeric body (such as a belt).

[0100] Table 3: Properties of Comparative and Exemplary Coating Compositions

[0101]

[0102] Figure 2a and 2b Related to the results in Table 2. Table 2 and Figure 2a and 2b Both indicate that the fabric substrates coated with the coating composition of the present disclosure exhibit better abrasion resistance than the fabric substrates coated with known coating compositions (such as the comparatives).

[0103] Figure 2a Depicted is a fabric substrate 100a coated with a coating composition within the range of coating formulations of Examples 1-10 described in this disclosure. Figure 2bDepicted is a fabric substrate 100b coated with a known coating composition similar to the comparative coatings disclosed herein. Figure 2a and 2b Each coated fabric substrate in was 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 substrate will be subjected to when rubbing against a pulley or gear after being coupled to an elastomeric body, such as a belt.

[0104] After 500 reciprocating abrasions, the fabric substrate 100a coated with a coating composition similar to the exemplary coating composition of the present disclosure did not leave any visible traces, as shown in FIG. Figure 2a As shown. The fabric substrate 100b coated with the comparative known coating composition exhibits significant wear 140, as shown. Figure 2b The values ​​in Table 2 support this result. The average coefficient of friction for Examples 1-4 ranged from 0.183 to 0.248, while the average coefficient of friction for Comparatives 1-11 ranged from 0.230 to 0.609. Due to the lower CoF, the fabric substrates coated with the coating composition of the present disclosure had increased abrasion resistance and showed no visible damage on the surface of the substrate.

[0105] Example 3

[0106] Cross section of a fabric substrate coated with a coating composition

[0107] Figure 3 Shown is a cross-sectional image 200 of an elastomeric body 210 with a fabric substrate 220 coated with a coating composition 230 of the present disclosure. The image 200 was obtained using a scanning electron microscope with electron acceleration of 5 to 20 kV, a working distance between 10 and 20 mm, and a backscattered electron detector magnification of 50x.

[0108] The coating composition 230 includes FeO as a marker. Figure 3 20. The coated fabric substrate 220 is shown as small black dots and was formulated using the formulation of Example 7 described below. The coated fabric substrate 220 is adhered to the elastomeric body 210, forming the fiberglass tensile thread layer 215. The concentration and degree of penetration of the coating composition 230 into the fabric substrate 220 can be observed using the markers. The depth of penetration 232 exceeds 50% of the total thickness of the fabric substrate 220.

[0109] Example 4

[0110] Exemplary coating compositions

[0111] Table 4 shows the composition of Comparative 1 and exemplary compositions 5-9. The filling factor is a measure of the percentage of the weight of the lubricant to the total weight of the binder and lubricant. When the filling factor of the lubricant to the total weight of the binder and lubricant exceeds 10%, all tribological properties are significantly improved, resulting in better damage scores and lower CoF. (See Table 4)

[0112] Table 4: Range of wax lubricant concentrations identified

[0113]

[0114] Example 5

[0115] Characteristics of Exemplary Coating Compositions

[0116] Table 5 shows the amount of lubricant, binder resin, and the percentage of lubricant to binder for Comparative 1 and Examples 5-11. The CoF of each of Comparative 1 and Examples 5-11 was tested using ASTM G99. Examples 5-11 showed a lower CoF than the Comparative, which may provide better wear resistance of the fabric substrate vulcanized on the elastomeric body against pulley or gear use.

[0117] Table 5: Measured tribological properties of a series of wax lubricated coatings

[0118]

[0119] As shown in Examples 1-5, exemplary compositions 1-9 exhibited improved abrasion resistance when applied to fabric substrates compared to known comparative coating compositions. Due to the enhanced abrasion resistance, the coating compositions of the present disclosure can extend the life of coated fabric substrates adhered to elastomeric bodies used in drive belt assemblies.

[0120] Wherein specific examples of the present invention have been described above for the purpose of illustration, it will be apparent to those skilled in the art that many detailed changes can be made to the present invention without departing from the present invention as defined in the appended claims. Therefore, this application is intended to cover any variation, use or adaptation of the present disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure within known or customary practices in the field to which the present disclosure belongs, and fall within the limitations of the appended claims.

[0121] Example 6

[0122] Exemplary Coating Composition - Carnauba Wax

[0123] Referring to Table 6, exemplary compositions 11 and 12 of the present disclosure were formulated using the following compositions.

[0124] Table 6: Formulation of Exemplary Coating Compositions 11 and 12

[0125]

[0126]

[0127] Table 7 shows the properties of Example 11 and Example 12 tested using the test parameters previously described in Table A. Damage scores were measured for Example compositions 11 and 12. The damage score was measured by comparison with an image standard in a calibrated ruler (Table 2) and is an indicator of the actual coating survival rate after tribological testing according to ASTM G99. Table 7 shows examples of coated substrates that exhibited different damage scores after exposure to tribological testing.

[0128] Table 7 further shows the coefficient of friction (CoF) of exemplary compositions 11 and 12 as measured by a tribometer according to ASTM G99. As shown in the table below, exemplary compositions 11 and 12 generally exhibit lower CoF than comparative compositions 1-11, thereby reducing the amount of wear on a fabric substrate adhered to an elastomeric body, such as a belt.

[0129] Table 7: Properties of Exemplary Coating Compositions 11 and 12

[0130]

Claims

1. A coating composition for a flexible substrate, comprising: 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 determined by ASTM D87; Polyethylene having a melting point of 80°C to 150°C as determined by ASTM D87; and solvent. 2 . The coating composition according to claim 1 , comprising a fluoropolymer in a total amount of 0.1 wt. % or less based on the total weight of the coating composition. 3 . The coating composition according to claim 1 , comprising the wax, and wherein the wax is at least one of carnauba wax and hydrocarbon wax.

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

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

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

7. The coating composition according to any one of claims 1 to 6, wherein the binder resin comprises at least one of: hydroxyl-functional polyesters reacted with isocyanates; and Polyurethanes reacted with carbodiimides.

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

9. The coating composition according to any one of claims 1 to 8, wherein a 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 . The coating composition according to claim 9 , wherein the weight ratio of the lubricating component to the binder resin is 0.25 to 0.66 based on the total weight of the lubricating component and the binder resin. 11 . The coating composition according to claim 10 , wherein the weight ratio of the lubricating component to the binder resin is 0.3 to 0.5 based on the total weight of the lubricating component and the binder resin.

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

13. A coated flexible substrate comprising: Flexible substrates; as well as A non-continuous cured coating impregnated within the flexible substrate, the non-continuous cured coating comprising: Binder resin; as well as A lubricating component comprising at least one of: a wax having a melting point of 80°C to 150°C as determined by ASTM D87; and Polyethylene having a melting point of 80°C to 150°C as determined by ASTM D87.

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

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

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

17. The coated flexible substrate according to any one of claims 13 to 16, wherein the binder resin comprises at least one of: hydroxyl-functional polyesters reacted with isocyanates; and Polyurethanes reacted with carbodiimides.

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

19. The coated flexible substrate according to any one of claims 13 to 18, 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.

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

21. The coated flexible substrate of claim 20, wherein the weight ratio of the lubricating component to the binder resin is from 0.3 to 0.5 based on the total weight of the lubricating component and the 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 of any one of claims 13 to 22, wherein the textile material is fused to an endless polymeric belt.

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 being configured to be permanently coupled to an elastomeric body, and the second side being 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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