Rubberised textile material, rubber mixture for the production of same and drive belt

Abstract

In a first aspect, the present invention relates to a rubberised textile material (1), this being provided as a belt support for power transmission belts, the rubberisation consisting of a rubber mixture comprising at least two rubbers from a group of chloroprene rubber, vinylpyridine-styrene-butadiene rubber and chlorosulphonated polyethylene rubber. Furthermore, the present invention relates to a corresponding rubber mixture, suitable for producing said rubberised textile material, and to drive belts (10, 22) having said rubberised textile material. Finally, a method is provided for producing corresponding drive belts having a belt body and a rubberised textile material according to the invention, said rubberised textile material being present on at least one side.

Description

[0001] RUBBERIZED TEXTILE MATERIAL, RUBBER COMPOUND FOR THE PRODUCTION THEREOF AND DRIVE BELTS

[0002] In a first aspect, the present invention relates to a rubberized textile material, which is intended as a belt overlay for power transmission belts, and wherein the rubber coating consists of a rubber mixture comprising at least two rubbers from the group consisting of chloroprene rubber, vinylpyridine-styrene-butadiene rubber, and chlorosulfonated polyethylene rubber. Furthermore, the present invention relates to a corresponding rubber mixture suitable for producing this rubberized textile material, as well as drive belts comprising these rubberized textile materials. Finally, a method for producing corresponding drive belts with a belt body and a rubberized textile material according to the invention present on at least one side is provided.

[0003] State of the art

[0004] Textile coatings on power transmission belts, such as timing belts, V-belts, or ribbed belts, improve power transmission between the power transmission belt and power transmission pulleys, such as timing belt pulleys. These textile coatings on corresponding power transmission belts serve to reduce abrasion and the tendency for tearing, for example, at the tooth edges of timing belts, as well as the tendency for tear propagation in the event of damage to the outer edge of the tooth.

[0005] There are various solutions for bonding textile coatings to the belt body. For example, in polyurethane belts, these polymers are generally poured directly onto the textile overlay, allowing the polyurethane to cure, crosslink, and solidify on the overlay. It is desirable for the polyurethane to at least partially penetrate and pass through the textile. However, the polyurethane present in the textile coating can lead to high coefficients of friction, especially when the textile coating is worn away and the polyurethane comes into direct contact with the pulleys.

[0006] Alternatively, adhesion promoters are placed between the base body and the textile overlay in drive belts, e.g., as described in DE 102008 055497 A1, to prevent excessive penetration of the vulcanizate into the textile overlay and to achieve a better chemical bond to the textile. Typically, the adhesion promoter reacts chemically during vulcanization and penetrates the textile overlay, forming a cross-linking effect. A variety of solutions have already been presented for bonding the textile overlay to the belt body. This applies particularly to the frequently used EPDM compounds and semi-finished products for the belt body.

[0007] In this case, for example, EP 3 456 778 B1 proposes, to improve adhesion, applying a peroxide-curable ethylene-alphaolefin (EAO) rubber mixture to at least one side of the textile material. The goal here is to increase the finishing stack of the mixture intended as a coating or rubber coating for a textile overlay without significantly impairing the dynamic properties of the product provided with the rubberized textile layer, as well as the adhesion between the textiles, and the elastomer base bodies equipped with it.

[0008] Alternative solutions for attaching the textile overlay to the belt body include a coating made of thermoplastic material, for example, to prevent the belt material from penetrating the textile overlay. An example of this is EP 2 795 155 B1, which describes the use of corresponding layers of thermoplastic material.

[0009] The invention is based on the requirement to modify the textile overlay in such a way that, on the one hand, it adheres well to the belt body and, on the other hand, minimizes abrasion of the textile overlay, thus reducing wear and frictional resistance. In particular, it is desired to provide rubberized textile materials suitable as belt textile overlays that do not require additional adhesion promoters for bonding to the belt body. Description of the invention

[0010] The invention solves the problem by providing a rubberized textile material suitable as a belt textile covering, wherein a rubber mixture is used for the rubber coating with at least two of the three rubbers mentioned below.

[0011] That is, in a first aspect, the present invention is directed to a rubberized textile material suitable as a belt textile covering, wherein the rubberized textile material is provided on at least one side with a rubber mixture and wherein the rubber mixture comprises at least two of the following three rubbers: a) chloroprene rubber (CR); b) vinylpyridine-styrene-butadiene rubber (VP-SBR); c) chlorosulfonated polyethylene rubber (CSM).

[0012] In a further aspect, the present invention is directed to a rubber mixture of the above-mentioned type, suitable for producing a rubberized textile material.

[0013] In addition, a drive belt or power transmission belt with at least one layer of the rubberized textile material according to the invention is provided.

[0014] Finally, a method is provided for producing a drive belt, in particular a V-belt, V-ribbed belt or toothed belt, with a belt body made of elastic material and tensile carrier with tensile strands, wherein the belt body has a rubberized textile material according to the invention on at least one side, comprising the steps of providing the reactants forming the belt body and applying the rubberized textile material according to the invention to at least one side of the belt body to be formed and forming the drive belt under the action of pressure and / or temperature on the reactants and the rubberized textile material in such a way that the rubberized textile material is present in an adhesive manner on at least one surface of the belt body.

[0015] The power transmission belts according to the invention are usually designed as endless belts and are therefore suitable for rotating around pulleys as often as desired in succession, thereby allowing mechanical work to be performed from one pulley to another by means of the power transmission belt for an in principle unlimited period of time. Drive belts usually have a base body or belt body that is elastic and essentially gives the drive belt its dimensional stability and shape. On a first side of the drive belt, it has a belt back. On the second side opposite the belt back with respect to the base body, the drive belt has a power transmission zone. The power transmission zone is designed to transmit forces between the outer surface of a pulley and the drive belt.To improve power transmission, particularly to reduce abrasion of the material forming the belt body, a textile overlay is often applied to the surface of the power transmission zone in order to increase service life and improve noise and smooth running.

[0016] The transmission of the drive force or the output force between a pulley and the drive belt or power transmission belt (these two terms are used synonymously below) can occur through positive locking and / or static friction and / or sliding friction. When the force is transmitted through static friction between the power transmission zone and a casing surface of a pulley, the power transmission zone can be flat, as in the case of flat belts, with a ribbed structure that remains constant in the running direction and cross-sectional profile, as in the case of V-ribbed belts, or with a trapezoidal cross-section that remains constant in the running direction and cross-sectional profile, as in the case of V-belts. Alternatively or additionally, the force can be transmitted through a positive locking between the power transmission surface and a casing surface of a pulley.In a drive belt designed as a toothed belt, for example, the elevations are formed as beams extending transversely to the running direction, which protrude from the power transmission zone at fixed intervals along the running direction and are designed to engage with grooves in the pulleys that are provided at correspondingly equal intervals along the outer surface of a pulley. Alternatively, the power transmission zone can have recesses, to which corresponding elevations are present on a pulley, so that the elevations engage with the recesses. However, the problem arises that when adhesion promoters are used to bond the textile material to the belt body, the service life of the fabric is reduced due to the stiffening. The adhesion promoter usually does not allow for precise tooth formation.Furthermore, the use of adhesion promoters requires additional process steps, which increase production costs. However, adhesion promoters are currently necessary to ensure the necessary adhesion between the fabric and the tensile elements formed from the belt body, such as the teeth in timing belts, in order to allow the necessary abrasion resistance. These conventional adhesion promoters are known to those skilled in the art. Currently, textile materials are therefore treated, also referred to as rubberized, by dipping the fabric, for example, in an RFL (resorcinol-formaldehyde latex) polymer mixture, in order to improve the bond to the tensile element and the abrasion behavior. However, these RFL polymers also require the aforementioned adhesion promoters, with the disadvantages mentioned above.Chloroprene rubbers are currently used to rubberize the textile material, which exhibits good abrasion resistance, especially in timing belts. However, the use of adhesion promoters is necessary to increase the service life of the belts. As mentioned, adhesion promoters increase production costs and lengthen the production process. Furthermore, the use of adhesion promoters often shortens the service life of the textile material before use in corresponding drive belts.

[0017] The inventive use of blends of at least two of the aforementioned rubbers, CR, VP-SBR, and CSM, allows this problem to be overcome. In particular, the use of the three rubbers CR, VPR-SBR, and CSM leads to the provision of rubberized textile materials for belt textile overlays. When used in drive belts, these materials exhibit good adhesion to the belt body while retaining good abrasion resistance and low wear, as well as a longer service life.

[0018] In particular, it was shown that the fabric weft modulus is improved. The fabric weft modulus in the weft direction, i.e., in the direction of the weft thread, is a measure of the stiffness of the fabric. The corresponding modulus is derived from the force-elongation diagram. In the rubberized textile material according to the invention, the elongation remains at a higher level over time and decreases more slowly than in standard fabrics. This can be explained by the fact that the stiffness of the rubberized textile material according to the invention is lower than that of those in which adhesion promoters are used.

[0019] The rubbers to be used, CR, VP-SBR and CSM are common commercially available rubbers.

[0020] The rubber mixture contains the respective rubbers in an amount of at least 10 wt.%. Typically, the rubbers are present in the rubber mixture in an amount of at least 50 wt.% based on the total amount of the rubber mixture. The proportions of each of the at least two or three rubbers can vary, with any rubber present in an amount of at least 10 wt.%.

[0021] In one embodiment, the rubberized textile material according to the invention does not contain an adhesion promoter. Rather, the rubberized textile material can be brought into direct contact with the materials forming the belt body. This means that no conventional adhesion promoter is present between the rubberized textile material and the material forming the belt body.

[0022] The rubberized textile material is coated on at least one side with a rubber mixture according to the invention. As an embodiment, the rubberized textile material is formed such that the rubber mixture present on at least one side of the rubberized textile material is in direct contact with the material forming the belt body. The rubberized textile material can also be coated completely on all sides with the rubber mixture according to the invention. The application, i.e., the coating or rubberization of the textile, can be carried out using known methods. These include dipping or doctoring, but also rubberizing calendering, both as a coating (on one or both sides) and as a friction coating (on one or both sides).

[0023] The resulting rubberized or coated textiles can usually be further processed and used as belt textile coverings.

[0024] Any textile material commonly used or suitable for belt textiles can be used for the invention, i.e., can be rubberized in the manner according to the invention. Suitable textile forms are woven, knitted, or nonwoven fabrics, as known to the person skilled in the art with regard to the qualities to be used, textile materials or threads and / or fiber materials, fiber thicknesses, fabric densities, weaves, and basis weights. In one embodiment, the textile material is selected from polyamide, polyester, aramid, or polyester-cotton blends. These materials can also be used in combinations.

[0025] In one embodiment, the textile material is, in particular, a polyamide. In the textile technology sense, the fabric overlay is a textile fabric consisting of the warp and weft thread systems. The warp thread system comprises warp threads. The weft thread system comprises weft threads. The warp threads extend in the longitudinal direction of the fabric overlay. The weft threads extend perpendicular to the warp threads and thus in the transverse direction of the fabric overlay.

[0026] The textile materials are common, commercially available textile materials, with the standard fabrics used being those in which the warp thread mass fraction is always greater than the weft thread mass fraction. This means that well-known textile materials already used for drive belts, including timing belts, V-belts, and multi-ribbed belts, are suitable.

[0027] In one embodiment, the warp fiber mass fractions of the warp threads and the weft thread mass fractions of the weft threads are such that the weft thread mass fraction is greater than the warp thread mass fraction in the corresponding textile material. Reference is also made to EP 3 822 399 A1, the content of which is hereby incorporated by reference. Rubberized textile materials according to the invention can be finished as textiles, as described therein.

[0028] In a further development of the invention, the rubber mixture contains further components, in particular fillers. These include, among others, carbon black and / or at least one mineral oxide, preferably silicon dioxide. Other fillers, such as aluminum oxides, calcium oxides, mixed oxides such as aluminum silicates, etc., may also be present. The filler content is preferably 5 to 60 phr, e.g., 5 to 40 phr of the filler or filler mixture. Furthermore, in addition to the main components of this rubber mixture, other additives may also be present, in particular accelerators, retarders, anti-aging agents, UV stabilizers, processing aids, activators, dyes, and the like. Corresponding conventional additives are known to those skilled in the art.

[0029] The belt body, also referred to as the base body, is produced according to the invention from a vulcanizate. The vulcanizate comprises a vulcanized rubber mixture. The rubber mixture comprises at least one or more rubber components and one or more mixture ingredients. The rubber component or components is / are selected from the group of rubber components, which includes in particular ethylene-propylene copolymer (EPM), ethylene-propylene-diene copolymer (EPDM), (partially) hydrogenated nitrous rubber (HNBR), chloroprene rubber (CR), fluororubber (FKM), natural rubber (NR), styrene-butadiene rubber (SBR), vinyl-methyl-silicone rubber (VMQ), or butadiene rubber (BR), and variants thereof, such as the aforementioned VP-SPR, or combinations thereof.The compounding ingredients comprise one or more crosslinkers or a crosslinker system consisting of crosslinker and accelerator, each of which initiates and / or accelerates the vulcanization of the rubber components.

[0030] Further blend ingredients may include one or more fillers, one or more processing aids, and / or one or more plasticizers, and / or one or more anti-aging additives, and / or fiber material, and / or color pigments. The base body may also comprise a conventional tensile reinforcement layer with tensile reinforcements. Suitable material arrangements are known to those skilled in the art.

[0031] The power transmission zone of a drive belt comprises the rubberized textile material according to the invention as a belt textile overlay. The belt textile overlay rests on the base body. The belt textile overlay is preferably not embedded in the vulcanizate along the fabric thickness with which it rests on the base body. This means that the fabric overlay covers the vulcanizate in the area of ​​the power transmission zone with a portion of its fabric thickness that is not embedded in the vulcanizate. In the power transmission zone, the belt textile overlay thus at least partially forms the surface.In particular, the power transmission zone is designed so that, during the intended rotation of pulleys, the textile belt covering and the pulleys accomplish the actual power transmission, in particular through frictional and / or adhesive force-locking and / or positive-locking interaction between the textile belt covering of the drive belt and the outer surface of the pulley. It was shown that the rubberized textile material according to the invention not only meets the requirements for adhesion to the belt body, but also demonstrates the necessary abrasion resistance and thus a sufficient service life of the belt. In particular, the weft thread modulus of the fabric was improved.

[0032] In a further aspect, the present invention is directed to the corresponding rubber mixture itself, suitable for producing the rubberized textile material. In one embodiment, the ratio of the at least two rubbers mentioned is such that, in a mixture of at least two of the rubbers mentioned, the proportion of one rubber is at least 10 wt. The other rubber components, or if three rubbers are present in the rubber mixture, the two other rubber components are also at least 10 wt.

[0033] In a further aspect, the present invention is directed to drive belts with at least one layer of the rubberized textile material according to the invention. In one embodiment, the rubberized textile material is arranged in the drive belt according to the invention such that it is applied as a support on at least one side of the belt. Alternatively, the rubberized textile material according to the invention can partially or completely enclose the belt as a sheath.

[0034] The drive belts have the usual additional components mentioned above, in particular the corresponding base body with, if necessary, a corresponding tension member layer. The belt backing can also have a fabric layer. If necessary, additional layers can be arranged between the belt body and the belt backing.

[0035] In one embodiment, the rubber mixture of the belt body partially flows into the rubberized textile material according to the invention. In one embodiment, the rubber mixture forming the belt body does not completely flow through the rubberized textile material to avoid being present on the surface of the power transmission zone. Partial inflow of the rubber mixture of the belt body can additionally improve the mechanical and chemical adhesion of the rubberized textile material to the belt body.

[0036] In one embodiment of the invention, the drive belt is a V-belt, V-ribbed belt, or toothed belt. In one embodiment, the drive belt is a toothed belt with a rubberized textile material according to the invention on the surface of the power transmission zone, the teeth.

[0037] In one embodiment, the belt body present in the drive belt according to the invention is made of an ethyl alpha olefin (EPO) rubber mixture, an ethylene propylene diene rubber (EPM) or mixtures thereof, in particular an ethylene propylene diene terpolymer (EPDM) rubber mixture.

[0038] In one embodiment, the drive belt according to the invention has no adhesion promoter between the rubberized textile material according to the invention and the belt body. Finally, the invention provides a method for producing a drive belt according to the invention, in particular a V-belt, V-ribbed belt or toothed belt. This has a belt body made of elastic material and tension members with tensile strands, wherein the belt body has a rubberized textile material according to the invention on at least one side. The method comprises the steps of providing the reactants of the elastic material of the belt body to be formed; applying the rubberized textile material according to the invention to at least one side of the belt body to be formed and vulcanizing, i.e.Forming the drive belt under the influence of pressure and / or temperature on the corresponding composition of the belt body and the rubberized textile material such that the rubberized textile material adheres to at least one surface of the belt body. In one embodiment, the elastic material of the belt body is EPM, in particular EPDM.

[0039] Corresponding manufacturing processes are known to those skilled in the art. Typically, the manufacturing process begins with heating and / or pressurization. This causes the rubber compound of the belt body to soften and thus mold it. The vulcanization process then begins. To produce the drive belt according to the invention as an endless belt, a corresponding annular vulcanization mold can be used, with the corresponding profile areas for forming the power transmission zone being oriented radially outward or radially inward, depending on the variant.

[0040] The invention will be explained in more detail below with reference to exemplary embodiments shown schematically in the drawings.

[0041] Figures 1A to C show the application of the rubberized textile material according to the invention in standard belts. The rubberized textile material 1 covers the power transmission zone 3 of the belt substructures. Also shown is the belt-typical arrangement of strength members 4. Figure 1A shows a V-belt with complete textile sheathing. The rubberized textile material 1 completely encloses the belt. Figure 1B shows a toothed belt with transversely arranged teeth 5 and longitudinally extending strength members 4. Here, the rubberized textile material 1 according to the invention covers the entire tooth surface, including supports, tips, and flanks. Figure 1C shows a flat belt whose textile overlay made of the rubberized textile material 1 according to the invention is limited to the inner surface.

[0042] Figure 2 shows another example of a drive belt according to the invention. It shows a longitudinal section through a toothed belt with a coating arrangement according to the invention on the tooth side. The drive belt shown in Figure 2 is a toothed belt 10, the belt body of which comprises a base body 11 and a power transmission zone 12. The power transmission zone 12 has teeth 13, between which there are interdental spaces 14. Tension cords 15, which typically consist of tension members arranged horizontally next to one another, run in the base body 11 in the longitudinal direction of the toothed belt 10.

[0043] In the exemplary embodiment, the surface of the power transmission zone 12 is covered by the rubberized textile material 16 according to the invention, which increases the wear of the toothed belt 10 in the area of ​​the power transmission zone 12. The rubber mixture 12 forming the power transmission zone can, if necessary, at least partially flow into the rubberized textile material 16. However, this polymer mixture is not found on the outer surface of the power transmission zone, formed by the rubberized textile material 16.

[0044] Figure 3 shows an exemplary embodiment of a V-ribbed belt 22 according to the invention with its various functional areas. The V-belt shown essentially consists of several elastic materials, in the present case of a belt body 27 or substructure on the power transmission side. The individual V-ribs 20 are formed on this belt body 27, in this case three V-ribs. The V-belts have corresponding rib flanks, via which the force is introduced or transmitted when engaging pulleys (not shown here). On the belt side facing away from the power transmission area 21 is the belt back 26, which can be made of the same material as the belt body 27 or of a different elastomer. The belt back 26 can, if desired, be multi-layered.In the illustration, the belt back 26 is formed as a single layer, which may be the same or a different elastomer than that of the belt body. Between the belt body 27 and the belt back 26 lies the tension member layer 28 made of spirally wound tension members. In this example, the tension members are processed as special embedding layers; separate tension member embedding would also be possible. In the example, the rubberized textile material 25 according to the invention is shown with indicated warp threads and weft threads. The rubberized textile material 25 lies on top of the material or, if necessary, partially immersed in the material, forming the outer layer and thus the surface.

Claims

Patent claims: 1) A rubberized textile material suitable as a belt textile covering, wherein the rubberized textile material is provided on at least one side with a rubber mixture and wherein the rubber mixture comprises at least two of the following three rubbers: a) chloroprene rubber (CR); b) vinylpyridine-styrene-butadiene rubber (VP-SBR); c) chlorosulfonated polyethylene rubber (CSM). 2) Rubberized textile material according to claim 1, which does not contain an adhesion promoter. 3) Rubberized textile material according to claim 1 or 2, wherein the rubber mixture present on at least one side of the rubberized textile material is in direct contact with the material forming the belt body. 4) Rubberized textile material according to one of the preceding claims, characterized in that all three rubbers a) to c) are present in the rubber mixture. 5) Rubberized textile material according to one of the preceding claims, characterized in that the textile material is one selected from polyamide, polyester, aramid or polyester-cotton blend, or combinations thereof. 6) Rubberized textile material according to claim 5, wherein the textile material is a polyamide. 7) Rubberized textile material according to one of the preceding claims, wherein the rubber mixture completely encloses the textile material. 8) Rubberized textile material according to one of the preceding claims, wherein further components, in particular fillers, are present in the rubber mixture. 9) Rubber mixture suitable for producing a rubberized textile material as defined in any one of claims 1 to 8. 10) Drive belt with at least one layer of rubberized textile material according to one of claims 1 to 8. 11) Drive belt according to claim 10, wherein the rubberized textile material is applied to at least one side of the belt as a support or encloses the belt as a sheath. 12) Drive belt according to one of claims 10 or 11, wherein the rubberized textile material is present as a belt support and wherein the belt side with the belt support represents the power transmission side. 13) Drive belt according to one of claims 10 to 12, characterized in that the belt is a V-belt, V-ribbed belt or toothed belt. 14) Drive belt according to one of claims 10 to 13, wherein the belt body of the drive belt is made of a rubber mixture of a propylene copolymer (EPM) rubber mixture, in particular an ethylene-propylene-diene terpolymer (EPDM) rubber mixture. 15) Method for producing a drive belt, in particular a V-belt, V-ribbed belt or toothed belt, with a belt body made of elastic material and tension members with tension strands, wherein the belt body has on at least one side a rubberized textile material according to one of claims 1 to 8, comprising the steps of providing the reactants for forming the belt body; Applying the rubberized textile material according to one of claims 1 to 8 to at least one side of the belt body to be formed and Forming the drive belt under the action of pressure and / or temperature on the reactants and the rubberized textile material such that the rubberized textile material is adhesively present on at least one surface of the belt body. 16) Method according to claim 15, wherein the elastic material of the belt body comprises EPM, in particular EPDM.

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