Toothed belt with low porosity canvas layer

Abstract

A toothed belt incorporating a canvas layer with low porosity, and a method for manufacturing a toothed belt. The canvas layer has a low porosity of 25% or less. The low porosity canvas layer reduces belt elongation, improves wear resistance, and consequently extends the belt's operating life.

Description

Technical Field

[0001] Reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 500,492, filed May 5, 2023, "Toothed Belt with Low-Porosity Canvas Layer", the entire content of which is incorporated herein by reference.

[0002] This application relates to a flexible belt for use with sprockets, and more particularly, to a toothed flexible belt having a canvas reinforcement layer.

Background Art

[0003] Power transmission belts generally operate in conjunction with toothed gears or sprockets, which engage the toothed belt and cause the belt to travel in response to the rotation of the gear or sprocket. If the belt / tooth stiffness is insufficient, it may stretch under load, and as a result, the teeth of the belt may become disengaged from the teeth of the gear or sprocket, which is called tooth skipping. Therefore, there is a need for a belt with limited elongation (stretch or elongation) under load.

Summary of the Invention

[0004] This summary is provided to introduce a simplified form of some concepts that will be further described in the following detailed description. This summary and the foregoing background art are not intended to identify the key aspects or essential aspects described in the claims. Further, this summary is not intended to be used as an aid in determining the scope of the subject matter described in the claims.

[0005] This disclosure relates to toothed belts used in other personal mobility systems, such as e-bikes, standard bicycles, wheelchairs, scooters including electric scooters, motorcycles, and other systems that use belts to transmit power for giving movement to the system. Toothed belts can also be used in drive systems, such as those including the mobility systems described above, which conventionally use chains and sprockets or gears to transmit power to a belt. Toothed belts can also be used in industrial drive systems and automotive applications.

[0006] This disclosure provides a toothed belt incorporating a canvas layer having low porosity, and a method for manufacturing a toothed belt. The low-porosity canvas layer reduces belt elongation, improves wear resistance, and consequently extends the belt's operating life.

[0007] In a particular embodiment, the disclosure describes a reinforced belt comprising a flexible body having a back and a front, a plurality of alternating teeth and lands defining the front, and an injected canvas layer adjacent to the front having a porosity of 20% or less. The canvas layer comprises a plurality of threads and an injected composition.

[0008] In another specific embodiment, the disclosure provides a method for manufacturing a reinforced belt. This method includes the steps of: injecting an injection composition into a base canvas to obtain a reinforced canvas having a porosity of 20% or less; and forming a toothed belt using the reinforced canvas embedded in the belt composition.

[0009] These and other aspects of the technology described herein will become apparent after considering the detailed description and drawings herein. However, it should be understood that the scope of subject matter described in the claims is determined by the claims themselves and not by whether or not they address some or all of the problems described in the background of the invention, or whether or not they include the features or aspects described in the abstract. [Brief explanation of the drawing]

[0010] Examples of the disclosed technology, including preferred embodiments, are described with reference to the following figures, and unless otherwise specified, the same reference numerals refer to the same components in different figures.

[0011] Figure 1 is a perspective view showing a section of a toothed belt that has been cut.

[0012] Figure 2 is an enlarged side view of the injected canvas showing its porosity.

[0013] Figure 3 is an enlarged side view of an injected multilayer canvas showing its porosity.

[0014] Figures 4A and 4B are graphs showing the belt thickness as a function of load.

[0015] Figure 5 is a step-by-step flowchart showing the process of forming the belt. [Modes for carrying out the invention]

[0016] As described above, this disclosure provides a toothed belt having a low-porosity reinforcing canvas layer incorporated near the tooth surface, and a method for manufacturing the same. In some embodiments, the canvas layer is exposed at the tooth surface.

[0017] The following description refers to the accompanying drawings, which constitute part of this specification and illustrate at least one specific embodiment. The following description also provides additional specific embodiments. These embodiments are disclosed in sufficient detail so that those skilled in the art can carry out the invention. It should be understood that other embodiments are conceivable and implementable without departing from the scope or spirit of this disclosure. Therefore, the following detailed description should not be construed as restrictive. This disclosure is not limited, but various aspects of this disclosure will be understood through the description of embodiments, including the following drawings. In some examples, reference numbers may have associated sublabels in lowercase to indicate one of several similar components. When a reference number is referred to without specifying a sublabel, the reference is intended to indicate all such several similar components.

[0018] Referring to the drawings, Figure 1 shows a portion of the belt 100. The belt 100 includes an elastomer body 102 having a back surface 104 and a front surface 106, the front surface 106 also called the sheave contact surface. This special front surface 106 has several alternately arranged transverse teeth 108 and lands 110, which are designed to mesh with grooved pulleys, gears, or sprockets when the belt 100 is in use. Although not shown in Figure 1, the belt 100 is typically an endless belt with a loop shape that has no start and end.

[0019] An internal reinforcing layer 112 is positioned within the body 102 to support and reinforce the belt 100. In the illustrated embodiment, the reinforcing layer 112 consists of a plurality of load-bearing cords 114 aligned longitudinally along the length of the body 102. These cords 114 may be in contact with each other or spaced apart. It should be understood that any type of reinforcing layer 112 known in the art can be used. The belt body 102 may include a reinforcing layer such as chopped fiber segments in addition to the load-bearing cords 114, but other reinforcing materials such as elongated segments, fibers, or nanotubes can also be used. The reinforcing material may be chopped, segmented, or elongated fibers as load-bearing cords 114, and may be, for example, aramid, polyester (PET), cotton, nylon, glass, carbon fiber cord, hybrid cord, metal, ceramic, or other plastic. The reinforcing material can be made from organic materials, synthetic materials, or mixtures of organic and synthetic materials. The reinforcing material can be treated with elastomer materials, such as polybutadiene elastomer. A size coating (e.g., epoxy, urethane) can also be applied before applying the treatment material.

[0020] In addition to the internal reinforcing layer 112 located within the main body 102, the belt 100 includes a reinforcing canvas 116 that is adjacent to or forms the front surface 106 of the belt 100. The reinforcing canvas 116 adheres closely to the alternately arranged teeth 108 and land portions 110, forming a surface cover or tooth cover for the sheave contact area. Some of the material forming the main body 102 may be present on the reinforcing canvas 116, but for the most part, the canvas 116 is present on the front surface 106 and forms the outer surfaces of the teeth 108 and land portions 110, following the shape of the teeth 108 and land portions 110.

[0021] The canvas 116 can be any desired configuration, for example, a conventional woven fabric consisting of warp and weft threads at any angle, or warp threads bundled by space pick cord, or a knitted or braided fabric, nonwoven fabric, etc. Multiple plies or layers of fabric may be used, including combinations of different types of fabrics. If necessary, the canvas 116 may be cut diagonally so that the strands form an angle (other than parallel or perpendicular) with respect to the direction of travel of the belt 100.

[0022] Conventional fabrics such as cotton, polyester, polyamide, acrylic, rayon, viscose, polyamide, polypropylene, polyethylene, polyketone, hemp, jute, glass fiber, and various other natural fibers, as well as synthetic fibers including blends or combinations thereof, can be used as the canvas 116. In some embodiments, the canvas 116 may include ceramic fibers, carbon fibers, or metal fibers. In one embodiment, the canvas 116 is a stretchable, abrasion-resistant canvas made of nylon in at least one of the warp or weft threads. In another embodiment, the canvas 116 is made from nylon 66 stretchable fabric and has an elastomer-free (e.g., polyurethane / urea-free) surface, which may be a coating or polymer film laminated to the canvas.

[0023] The porosity of the canvas 116 is less than 20% or 20% or less, less than 15% or 15% or less in some embodiments, less than 10% or 10% or less in other embodiments, and less than 5% or 5% or less in yet other embodiments. To achieve this porosity, the base canvas is injected, impregnated, permeated, or coated with a composition that reduces the porosity of the canvas 116 by volume to less than 20% or 20% or less, less than 15% or 15% or less in some embodiments, less than 10% or 10% or less in other embodiments, and less than 5% or 5% or less in yet other embodiments. The injected composition at least partially covers the yarns of the canvas and fills at least some of the spaces between the yarns of the canvas.

[0024] By making the porosity of the canvas 116 less than 20%, and in some embodiments even less, the wear resistance of the belt is improved, and thus the belt life is also improved. The wear, and thus the life, of the belt is improved by the increased wear resistance resulting from the low porosity. By reducing the porosity of the canvas 116, the exposed area of the threads of the canvas is reduced, reducing the possibility of physical wear and damage to the threads due to engagement with sprockets, gears, or wheels, and also reducing the possibility of environmental degradation of the threads due to exposure to fluids (such as oil, lubricants, etc.) and particulate contaminants in the air.

[0025] The belt life is also improved by the reduction in the elongation of the belt due to the low porosity, so that as a result, the physical strain applied to the teeth 108 when the teeth engage with a sprocket, gear, or wheel is reduced. It has been found that at least part of the reduction in the elongation of the belt is due to the reduction in the thickness of the canvas when tension is applied, i.e., the collapse of the porosity within the canvas and the resulting internal movement. By reducing the porosity of the canvas 116, the canvas 116 is more stable even under tension. The improved stability causes the teeth 108 to be more stabilized and less flexible. Further, the reduction in the compression of the canvas 116, and thus the belt 100, under load results in a reduction in elongation, and thus an improvement in the belt life. The reduction in compression occurs because the compressible canvas 116 has a low porosity.

[0026] Generally, the reduction in elongation suppresses "tooth skipping" that occurs when a toothed belt elongates under load and slips relative to a gear, i.e., "jumps". When tooth skipping occurs, the teeth do not engage with the drive mechanism, i.e., do not mesh correctly. Generally, a belt having an elongation rate of less than 0.25% for an incremental load of 1500 N provides desirable operating performance. In some embodiments, the belt has an elongation rate of less than 0.22% for an incremental load of 1500 N.

[0027] Reducing elongation and compression optimizes the belt's fit to the gear or sprocket, improving its ability to maximize the interaction between the belt surface and the gear or sprocket surface. Optimized fit means that the system's calculated performance falls within criteria supported by experimental and simulation data, such as stress analysis using finite element models. Specific criteria include the tension required to wrap (fit) the belt around the wheel (also known as pitch equalization tension (PET)), the maximum load transmitted between a single belt tooth and a wheel groove (also known as maximum tooth load (MTL)), and the absence of loads that hinder efficient power transmission between the belt and wheel (known as negative tooth load). These criteria can be adjusted to specific optimization goals; for example, noise, vibration, and / or harness (NVH) adjustments may focus on a narrower range or subset of the endurance range. Adjustments may also be made to improve NVH using a subset of the criteria, and in some embodiments, the NVH criteria are predetermined.

[0028] These criteria can not only determine the optimal fit but also determine how far the fit of the system deviates from the optimum and whether it is within the tolerance range. Specifically, the pitch colliding tension is maintained between a minimum value and a maximum value, which can be determined by experimental results and is supported by contour maps that identify the optimal and non-optimal regions based on, for example, stress and wear indices by finite element analysis (FEA). The ideal maximum tooth load is based on the theoretical minimum load (where all loads are evenly distributed between the meshing teeth), and the ratio of the maximum tooth load to the theoretical minimum load is considered based on the recognition that the durability of the belt decreases as the maximum tooth load increases. In summary, a non-optimal fit is any of the cases where the pitch colliding tension is below the minimum criterion, the pitch colliding tension exceeds the maximum criterion value, or there is a negative tooth load. The tooth load considered independently of bending and other fatigue factors is exponentially affected by the tooth load, so optimization is considered when the maximum load is less than the load obtained with a "matching" fit. As the elongation of the belt decreases, it becomes easier to obtain a matching fit.

[0029] Figure 2 shows an example of canvas 200 in which a composition has been injected to achieve a porosity of 20% by volume or less, 15% or less in some embodiments, 10% or less in other embodiments, and 5% or less in yet other embodiments, where the porosity is calculated based on the volume occupied by the canvas, the injected composition, and the pores. The canvas 200 in Figure 2 is a single-layer woven fabric consisting of woven warp threads 202 and weft threads 204, formed from, for example, nylon. The canvas 200 has three-dimensional properties due to the weaving of the threads 202 and 204 and the non-planarity of the individual threads 202 and 204. The composition 210 is present on the threads 202 and 204, coating and enclosing at least a portion of the surface of the threads 202 and 204. Generally, 100% of the volume between the threads 202 and 204 is not coated with composition 210, but rather a certain amount of pores 206 remain between the coated threads 202 and 204. In other words, a certain amount of air remains within the canvas 200. This amount of air, i.e., the porosity, is 20% or less of the volume of the canvas 200. In some embodiments, the pores 206 are the volume near the intersection of threads 202 and 204. The pores 206 may have different shapes and / or sizes within the canvas 200. Furthermore, the coating of composition 210 may be thicker or thinner.

[0030] Figure 3 shows another example of fabric 300 having a porosity of 20% or less by volume, having a porosity of 15% or less in some embodiments, 10% or less in other embodiments, and 5% or less in yet other embodiments. Fabric 300 is a multilayer fabric consisting of layers of interwoven warp threads 302 and weft threads 304. Fabric 300 has three-dimensional properties due to the weaving of the threads 302 and 304 and the non-plane nature of the individual threads 302 and 304 within each layer. Composition 310 is present on the threads 302 and 304, coating and enveloping at least a portion of the surface of the threads 302 and 304. Generally, rather than 100% of the volume between the threads 302 and 304 being coated with the composition, pores 306 remain between the coated threads 302 and 304. These pores 306 may have different shapes and / or sizes within the canvas 300.

[0031] In this canvas 300, the holes 306 are internal holes and are not uniformly distributed throughout the canvas 300, but are mainly located inside the canvas 300, i.e., in two layers of warp threads 302 and weft threads 304, and the outer surfaces of the outer threads 302 and 304 are substantially completely coated. In other embodiments, the outer surfaces of the threads 302 and 304 may be coated more or less. Furthermore, the coating of composition 310 may be thicker or thinner.

[0032] Note that while both canvas 200 and 300 shown in the illustration are woven fabrics with warp and weft threads, other woven fabrics such as knits, braids, nonwovens, and felt can also be used. Similar to canvas 200 and 300, voids or porosity remain in the vicinity of where fibers or threads intersect, particularly within the fabric.

[0033] Regardless of whether the porosity of canvas 200, 300 is uniformly distributed throughout the canvas, injected, permeated, coated, or impregnated canvas 200, 300 has a compression value that correlates with the amount of porosity of canvas 200, 300. The compression of canvas 200, 300 is determined by the change in the thickness of canvas 200, 300 under load (when the belt is mounted on two wheels, gears, or sprockets and a load is applied) when incorporated into a belt.

[0034] Compression of canvas occurs not only due to the breakdown of porosity within the canvas, but also due to the elongation of the belt caused by the stretching of the reinforcing layer within the belt (for example, reinforcing layer 112, such as code 114 in Figure 1), and this is a function of Young's modulus. By knowing the compression of the canvas due to the stretching of the reinforcing layer, it is possible to calculate the compression of the canvas due to porosity.

[0035] Figures 4A and 4B show examples where the compression of canvas was reduced by injecting a composition that reduces porosity into the canvas.

[0036] Figure 4A shows Graph 400, which illustrates the compression difference between canvas and injected canvas. In Graph 400, line 402 shows a belt made from standard base canvas under various loads, and line 404 shows a belt made from the same canvas that has been injected under various loads. As shown in Figure 4A, the belt using injected canvas has higher compression resistance than the belt using original canvas, and the compression difference increases as the load increases. The slope of line 404 is significantly smaller than the slope of line 402.

[0037] Figure 4B shows Graph 410, which tests belts incorporating both base canvas and injected canvas under loads of 250 N and 2,000 N. As shown in Figure 4B, belts using injected canvas exhibit significantly less thickness reduction and, consequently, less compression than belts using base canvas.

[0038] For example, original canvas with a thickness of approximately 400 micrometers is compressed by about 25 micrometers, but the same canvas, when injected, is compressed by about 6 micrometers under the same load.

[0039] The amount of compression measured along the thickness of canvas 200, 300 is 5% or less of the uncompressed thickness of canvas 200, 300, and in other embodiments, 4% or less, and even 3% or less. The correlation between the amount of compression and the applied load depends on the physical properties of the canvas and the injection composition, and may be linear, exponential, quadratic, or undefined, for example.

[0040] Injection compositions most commonly contain polymer materials as their base component, but other materials such as metals and ceramics can also be used as the base component. Suitable polymer materials include latex, polyurethane, vinyl, ethylene, acetate, and rubber, but other materials can also be used. In addition to the base material, injection compositions may contain various additives such as activators, fillers, curing agents, reinforcing agents, degradation inhibitors (e.g., antioxidants, UV stabilizers), plasticizers, antistatic agents, colorants, processing aids, homogenizers, copolymerizers, and catalysts. Various additional functional components can be added to this composition, and any composition, to modify, for example, the coefficient of friction, resistance to environmental exposure, and toughness of the material.

[0041] The injection composition may have a solid content of, for example, about 10-50%, and in some embodiments, about 20-30%, for example, 25%. The injection composition may have a viscosity of, for example, about 25 cps. The lower the solid content and / or viscosity, the more thoroughly and uniformly the composition can be injected into the fabric, especially in multilayer fabrics.

[0042] In one particular embodiment, the canvas impregnation composition comprises hydrogenated nitrile butadiene rubber (HNBR), silica (for example, used as a filler and for structural improvement), and suitable curing agents and reaction accelerators. Various additional functional components can be added to this composition, and to any other composition, to modify the coefficient of friction and the toughness of the material.

[0043] The components constituting the injection composition can be mixed by conventional mixing methods. In some embodiments, mixing is generally performed using an industrial mixer such as a Banbury mixer to mix all the components, but other mixing techniques and methods can also be used. In some embodiments, the individual components are added to the mixer in a specific order to ensure thorough mixing and dispersion of the components. In some implementations, certain raw materials can be mixed together before being added to the mixture in sequence.

[0044] The resulting impregnation composition can be applied to the canvas by conventional coating methods such as dipping, spraying, or knife coating. In some embodiments, the amount of impregnation composition on and within the canvas is 5–25 vol% and in some embodiments, it is about 8–20 vol%. The impregnation, infiltration, coating, or impregnation process can be carried out by atmospheric pressure, high pressure to push the composition into the canvas, or by creating a vacuum in the canvas to draw the composition into the canvas.

[0045] The injection compositions described herein are formulated to be compatible with canvas (e.g., nylon and any coating) and belt compositions comprising rubber, milled pre-urethane (MPU) and thermoplastic polyurethane (TPU), and ethylene elastomer (EE). Bonding of the injection composition to the belt composition (e.g., including crosslinking) may occur by hydrogen bonding, electrostatic / ionic bonding, dipole interactions, van der Waals interactions, and / or covalent bonding. The curing process may be initiated or accelerated by peroxide or sulfur radicals, or photoinitiated radicals (e.g., derived from UV, visible light, or IR photoinitiators).

[0046] Returning to Figure 1, the material of the body 102 of the belt 100 is not generally limited, and any suitable material can be used. Many examples of suitable materials / components for the body 102 of the belt 100 are described below. Typically, the base material used for the belt body 102 and teeth 108 is a natural or synthetic rubber material, a polymer material such as polyurethane, but other suitable materials can also be used. The material of the belt body and / or teeth may also include various fillers to further enhance the structural stability of the belt, although in other embodiments the belt may be free of fillers or substantially free of fillers. The belt 100 shown in Figure 1 may also include additional features not shown in Figure 1. For example, a cover layer (e.g., a coating) may be provided on the outer surface of the teeth 108, or a fibrous or polymer backing layer may be provided on the back surface 104 of the body 102 opposite the front surface 106 having the teeth 108 and land portion 110.

[0047] The belt body 102 is made of a moldable, flexible material, such as rubber, polyurethane, or polyethylene. Suitable materials include, for example, polyurethane elastomers (including polyurethane / urea elastomers and so-called mirabile gums) (PU), polychloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), hydrogenated NBR (HNBR), styrene-butadiene rubber (SBR), alkylated chlorosulfonated polyethylene (ACSM), polyepichlorohydrin, polybutadiene rubber (BR), natural rubber (NR), and ethylene alpha-olefin elastomers such as ethylene propylene copolymer (EPM), ethylene propylene dienterpolymer (EPDM), ethylene octene copolymer (EOM), ethylene butene copolymer (EBM), ethylene octene terpolymer (EODM), ethylene butene terpolymer (EBDM), ethylene vinyl acetate elastomer (EVM), ethylene methyl acrylate (EAM), silicone rubber, or combinations of two or more of these.

[0048] The raw materials that form the belt body are often in the form of solid powder, pellets, bales, or blocks, but may be liquid or semi-liquid depending on the embodiment.

[0049] The belt composition may contain peroxides or other accelerators to accelerate the curing of the composition. Various types of organic peroxides can be used, which decompose at specific temperatures, generating radicals that initiate crosslinking reactions in the compound. A specific example of an organic peroxide used in polyethylene is α,α-bis(t-butylperoxy)diisopropylbenzene.

[0050] Polymer compositions cured with organic peroxides exhibit higher heat resistance due to the formation of CC crosslinks between polymer chains. In contrast, sulfur-cured polymers form CSC or C-(S)xC bonds. The formation of monosulfide bonds (i.e., CS) or polysulfide bonds (i.e., SS) reduces the heat resistance of the polymer. Sulfur crosslinking can lead to reduced oxidation resistance. The CC bond energy (346 kJ / mol) is higher than the CS bond energy (272 kJ / mol) and SS bond energy (226 kJ / mol), which is reflected in the higher heat resistance of peroxide-cured vulcanized products.

[0051] The belt composition may contain various additives such as activators, fillers, curing agents, strengthening agents, degradation inhibitors (e.g., antioxidants, UV stabilizers), plasticizers, antistatic agents, colorants, processing aids, homogenizers, co-curing agents, and catalysts. Generally, the total weight percentage of such additives is less than 75% by weight of the total raw materials of the composition, and in some embodiments, it is less than 65% by weight or less than 50% by weight.

[0052] Examples of activators include stearic acid and zinc oxide.

[0053] Any suitable curing agent or material can be used, as these agents accelerate or assist the curing process. Examples of suitable curing agents include sulfur and peroxides.

[0054] Silica may be added to the belt composition to increase its tensile strength, modulus of elasticity, compression set, and wear resistance. Silica is usually in the form of a solid, such as a powder, and may be treated or untreated. Treated silica materials have low hygroscopicity and significantly reduce the generation of volatile matter during mixing and processing.

[0055] Carbon black and / or graphite can be used as fillers in rubber compounds. Other fillers include metal oxides such as aluminum oxide, magnesium oxide, and zinc oxide, as well as clay, montrillonite clay, pulp, and mica.

[0056] Generally, polymers degrade when exposed to various environmental factors such as oxygen, heat / temperature, ultraviolet light, weathering, catalytic degradation by heavy metal ions, and dynamic fatigue. Damage observed in rubber compounds due to environmental degradation includes a decrease in elastic and tensile strength, the formation of cracked surfaces, and the occurrence of cracks. The presence of unsaturated groups in the polymer may increase the tendency for damage due to thermal aging due to the allyl-CH bonds in the unsaturated chemical structure. The bond energy of allyl-CH is the weakest of the different types (primary, secondary, and tertiary) of CH bonds. This factor promotes the formation of free radicals and peroxyl radicals in the presence of oxygen and heat, causing chain severance and crosslinking. It should be noted that excessive crosslinking can cause embrittlement. When the polymer backbone degrades or is severed, the compound begins to lose physical and mechanical strength, and its physical properties also begin to deteriorate. Antioxidants act as radical traps, capturing radicals to prevent polymer chain severance, stabilizing properties, and improving the service life of the product.

[0057] Antioxidants that can be used in belt compositions include polymerized quinoline derivatives and 1,2-dihydro-2,2,4-trimethylquinoline. Other antioxidants include condensates of alkylated imidazole with diarylamine or ketone, and condensates of mercaptobenzimidal with diphenylamine / acetone. These are potent, non-contaminating antioxidants for natural and synthetic rubber, providing excellent heat resistance and flexural resistance even at high temperatures.

[0058] Plasticizers can be added to belt compositions for various reasons, including increasing flexibility and pliability, lowering the glass transition temperature, suppressing crystallization, increasing dispersibility, and reducing the cost of the composition. Common plasticizers include mineral oil and esters such as phthalates, sebacates, and adipices.

[0059] Dialkyl esters and dioctyl adipates (DOA) are highly efficient plasticizers that can be used to impart excellent low-temperature flexibility and impact resistance to belt compositions. In addition to their high efficiency and contribution to low-temperature properties, they are chemically stable and resistant to discoloration even under prolonged exposure to high temperatures and ultraviolet light. The combination of low viscosity and efficiency results in excellent dry-blending and processing properties.

[0060] Microcrystalline wax can be added as a physical ozone degradation inhibitor. Polymer chains containing double bonds are susceptible to ozonolysis and chain severance in the presence of ozone. Microcrystalline wax forms a shielding layer or barrier on the composition, protecting it from degradation due to chain severance.

[0061] Modified resorcinol, which is a resorcinol-formaldehyde homopolymer resin modified with a selected group, can be used as a pre-condensed dry adhesive and is chemically a resorcinol-formaldehyde homopolymer resin modified with a selected group. Modified resorcinol can promote adhesion of belt compositions to elastomer adhesive compositions.

[0062] Metallic acrylates, such as zinc dimethacrylate, can be used to improve the physical and mechanical properties of belts, acting as co-agents. In the presence of organic peroxides, metal co-agents form ionic bonds, improving the tear strength, modulus of elasticity, and flexural resistance of the composition.

[0063] Modified polybutadiene (e.g., maleic anhydride) can be used as an adhesion promoter for peroxide-cured vulcanized products. Chemically, it is a low molecular weight, low vinyl-content butadiene into which maleic anhydride functional groups have been introduced. These anhydride functional groups react with epoxy groups, amine groups, and hydroxyl groups, enabling the manufacture of unique adhesives, sealants, encapsulants, and coatings. It also improves compatibility with non-polar elastomers such as EPDM, enhancing the adhesion of peroxide-cured elastomers to polyester, aramid, or metal substrates.

[0064] Substituted phenol derivatives can be used as scorch inhibitors in peroxide curing systems. Substituted phenol derivatives initially form adducts to capture radicals from the peroxide, affecting processability and flow time into the composition.

[0065] Polymers and other components can be mixed using conventional rubber mixing methods. In some implementations, mixing is generally done using industrial mixers such as Banbury mixers to combine all the raw materials, but other mixing techniques and methods can also be used. For example, roll mills and closed mixers can be used. In some implementations, individual raw materials are added to the mixer in a specific order to ensure thorough mixing and dispersion of the raw materials. In some implementations, certain raw materials can be mixed before being added to the mixture in sequence.

[0066] Any of the above materials can be used, for example, to form a belt having a low-porosity woven reinforcement layer for power transmission, which will have a longer lifespan compared to a similar belt having, for example, a high-porosity woven layer. Figure 5 shows a general method for manufacturing a belt having cords coated with an injection composition.

[0067] Figure 5 shows an exemplary method 500 for forming a toothed belt as described herein. In the first step 502, a composition such as a polymer composition is injected into a canvas material. This composition is cured to obtain a low-porosity canvas having a porosity of 20% or less, and in some embodiments even lower. In the second step 504, the components are mixed to prepare the belt composition. In step 506, the belt is formed by placing the belt composition and the injected canvas material in a mold, which forms multiple teeth and lands on one side of the belt. The formed material is cured as needed, and the belt is removed from the mold.

[0068] In addition, the steps in method 400 may be carried out in an order other than that described above. For example, the belt composition may be prepared before being injected into the canvas material.

[0069] From the above, it will be understood that while specific embodiments of the present invention are described herein for illustrative purposes, various modifications are possible without departing from the scope of the invention. Features or elements of one embodiment may be used in combination with or replaced with features or elements of another embodiment. Accordingly, the present invention is limited only by the appended claims.

[0070] While this technology is described using terminology specific to certain structures and materials, it should be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Rather, certain embodiments are described as forms of carrying out the claimed invention. Many embodiments of the present invention can be carried out without departing from the spirit and scope of the invention, and the present invention is described in the appended claims.

[0071] Unless otherwise specified, all numerical values ​​or expressions used herein (excluding the claims) that describe size, physical properties, etc., are understood to be modified in all instances by the term "approximately." At a minimum, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter described in the specification or claims that is modified by the term "approximately" should be interpreted by taking into account the number of significant figures stated and by applying rounding techniques. Furthermore, all ranges described herein should be understood to encompass and support the claims describing all subranges or all individual numerical values ​​contained therein. For example, a range described as 1 to 10 should be considered to encompass and support the claims describing all subranges or individual numerical values ​​between and / or including a minimum value of 1 and a maximum value of 10. That is, all subranges starting with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, etc.) or 1 to 10 (e.g., 3, 5.8, 9.9994, etc.).

Claims

1. It comprises a flexible body having a back and a front, the body having a plurality of teeth and lands defining the front, The reinforcing canvas layer is provided near the aforementioned front surface, and the reinforcing canvas has a porosity of 20% or less. Reinforced belt.

2. The reinforced belt according to claim 1, further comprising an internal reinforcing layer between the back surface inside the main body and the reinforcing canvas layer.

3. The reinforced belt according to claim 2, wherein the internal reinforcing layer comprises a plurality of cords extending longitudinally along the length of the belt.

4. The reinforced belt according to claim 1, wherein the porosity of the reinforcing canvas is less than 15%.

5. The reinforced belt according to claim 1, wherein the porosity of the reinforcing canvas is less than 10%.

6. The reinforced belt according to claim 1, wherein the porosity of the reinforcing canvas is less than 5%.

7. The reinforced belt according to claim 1, wherein the reinforcing canvas comprises nylon threads.

8. The reinforced belt according to claim 7, wherein the reinforcing canvas further comprises hydrogenated nitrile butadiene rubber (HNBR) and silica.

9. A flexible body having a back and a front, with a plurality of alternating teeth and lands defining the front, A reinforced belt comprising an injected canvas layer adjacent to the front surface and having a porosity of 20% or less, wherein the canvas layer comprises a plurality of threads and an injected composition.

10. The reinforced belt according to claim 9, wherein the canvas layer is made of a woven fabric.

11. The reinforced belt according to claim 10, wherein the woven material has a plurality of woven layers.

12. The reinforced belt according to claim 11, wherein the porosity is mainly located inside the canvas layer.

13. The reinforced belt according to claim 9, wherein the porosity is evenly distributed across the canvas layer.

14. The reinforced belt according to claim 9, wherein the yarn contains nylon, and the injection composition comprises hydrogenated nitrile butadiene rubber (HNBR) and silica.

15. The objective is to obtain reinforced canvas with a porosity of 20% or less by injecting an injection composition into base canvas, Forming a toothed belt in which the aforementioned reinforced canvas is embedded in the belt composition. Equipped with A method for manufacturing reinforced belts.

16. A reinforced canvas layer for a flexible belt comprising a plurality of threads, each thread being nylon coated with an injection composition comprising rubber and particulate filler, wherein the porosity of the canvas layer is 10% or less.

17. The canvas layer according to claim 16, wherein the rubber comprises hydrogenated nitrile butadiene rubber (HNBR) and the particulate filler contains silica.

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