Article, in particular drive belt, with a textile covering

Abstract

The invention relates to an article comprising an elastomeric main body on the basis of at least one rubber compound with a surface of the article that is susceptible to noise and wear and is provided with a textile covering. The textile covering of the elastomeric article contains Lyocell fibres or completely consists of Lyocell fibres.

Description

[0001] Description

[0002] Articles, in particular drive belts, with a textile covering

[0003] The invention relates to an article having an elastomeric base body based on at least one rubber mixture with a noise- and wear-prone article surface provided with a textile overlay.

[0004] An article exposed to dynamic loads and thus to wear and noise generation includes, for example, a belt, strap, hose, air bellows, compensator, or multi-layer fabric. The belt, in the form of a drive belt, is particularly important. The elastomeric base of the drive belt comprises a cover layer as the belt backing and a substructure with a power transmission zone.

[0005] Products with an elastic base body are coated with a textile overlay on the surface to adjust the product properties. In addition to wear resistance and noise reduction, in the case of drive belts, this also includes improved power transmission. This poses problems when these products are intended or required to be used in humid environments. In such cases, it is currently no longer possible to meet the requirements for all required physical properties to the same extent.

[0006] The object of the present invention is to provide an article with an elastomeric base body, which has at least one textile overlay on at least one surface of the article and whose physical properties remain at a good level even in moisture or in a humid environment. Advantageously, the material for the textile overlay is also based entirely or partially on sustainable and / or renewable raw materials. This object is achieved by the textile overlay of the elastomeric article containing lyocell fibers or consisting entirely of lyocell fibers.

[0007] The terms “elastomeric article” and “article with an elastomeric base body” are used synonymously in this document.

[0008] Good properties in wet or humid environments are already known for naturally occurring cellulose-based fibers, such as cotton. However, these properties essentially result from the special surface structure of the natural fibers. Previous experiments with imitations of this fiber type in the form of other regenerated fibers, such as viscose, showed, however, that significant losses in wet properties occurred. Therefore, it has been very surprisingly shown that the use of lyocell fibers as a textile overlay in elastomeric articles has a beneficial effect on use in humid or wet environments.

[0009] At the same time, the use of Lyocell makes an important contribution to sustainability.

[0010] Lyocell (CLY) is a cellulose fiber made from regenerated cellulose, produced using the lyocell process (direct solvent process). The solvent used in the manufacturing process can be almost completely recycled. This results in a drastic reduction in environmentally harmful waste compared to conventional cellulosic chemical fibers (such as viscose). It is primarily made from wood from sustainable forestry and is biodegradable.

[0011] The structure of lyocell fibers differs from that of viscose. Specific characteristics include long crystallites, reduced cluster formation, and elongated voids. There are also differences in the fiber structure. Lyocell fibers consist of fibrils of equal thickness distributed across the cross-section.

[0012] The lyocell fibers can be in the form of staple fibers or filament fibers. In an advantageous embodiment, the textile overlay consists entirely of lyocell fibers, i.e., the proportion of lyocell fibers is 100% by weight.

[0013] It is also possible for the textile overlay to contain lyocell fibres, preferably in amounts of 20 to 95% by weight.

[0014] Preferably, the textile overlay, which consists of or contains lyocell fibers, is formed as a knitted fabric. If the textile overlay consists of lyocell fibers, the basis weight is preferably between 70 g / m 2 and 350 g / m 2 and most preferably between 100 g / m 2 and 250 g / m 2 .

[0015] If the textile covering contains lyocell fibres, at least one other material may be included in quantities of 5% to 80% by weight.

[0016] If the lyocell fibers are used in combination with at least one other material, this is referred to as a hybrid system or hybrid fiber construction.

[0017] As materials for the at least one further material of the textile overlay, all of the textile materials known to those skilled in the art and suitable can be used, which are preferably selected from the group consisting of: polyethylene (PE), such as UHMWPE, LDPE, LLDPE, or polyamide (PA), e.g. PA5.6, PA4.10, PA6, PA6.6, PA11, PA12, PA6.10, PA6.12, or copolyamides or polyester (PES) or rayon or polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) or

[0018] Polybutylene ephthalate (PBT) or polycarbonate (PC) or unsaturated polyester resin (UP) or poly(1,4-cyclohexanedimethylene terephthalate) (PCDT) or natural fibers such as wool, linen, hemp, cotton, or polyvinyl alcohol (PVAL) or polyoxybenzonaphtoate or polyvinyl acetal (PVA) or polyketone (POK) or polyetheretherketone (PEEK) or polyethylene 2,6-naphthalate (PEN) or polyphenylene or polyphenylene oxide (PPO) or polyphenylene sulfide (PPS) or polyphenylene ether or polybenzoxazole (PBO) or polyoxadiazole (POD) or polyetherimide (PEI) or m-aramid or p-aramid or polypropylene or melamine or highly crystalline polymer fibers or polyurethane (TPU). The materials mentioned can also be used in recycled form, i.e. as recovered material. The textile covering can be made of felt, fleece, fabric, braid, knitted or crocheted fabric or scrim.If the elastomeric article is a drive belt, the textile covering is preferably made of woven or knitted fabric.

[0019] Any rubber known to a person skilled in the art can be used as the rubber compound for the base body, either individually or in combination. Rubbers are often also referred to as elastomers, so both terms are used synonymously in this document.

[0020] Preferably, the rubber is selected from the group consisting of ethylene-propylene copolymer (EPM) and / or ethylene-propylene-diene copolymer (EPDM) and / or nitrile rubber (NBR) and / or (partially) hydrogenated nitrile rubber (HNBR) and / or fluororubber (FKM) and / or chloroprene rubber (CR) and / or natural rubber (NR) and / or styrene-butadiene rubber (SBR) and / or isoprene rubber (IR) and / or butyl rubber (IIR) and / or bromobutyl rubber (BIIR) and / or chlorobutyl rubber (CIIR) and / or butadiene rubber (BR) and / or chlorinated polyethylene (CM) and / or polyepichlorohydrin (ECO) and / or ethylene-vinyl acetate rubber (EVA) and / or acrylate rubber (ACM) and / or ethylene acrylate rubber (AEM) and / or silicone rubber (MQ, VMQ, PVMQ,FVMQ) and / or fluorinated methyl silicone rubber (MFQ) and / or perfluorinated propylene rubber (FFPM) and / or perfluorocarbon rubber (FFKM) and / or elastomeric polyurethane (PU).

[0021] If the article is a drive belt in particular, EPDM, EPM, NBR and HNBR are preferably used alone or in combination.

[0022] However, it is also possible for the rubber mixture to contain at least one thermoplastic elastomer and / or at least one thermoplastic, such as polyvinyl chloride (PVC), in amounts of 0 to 50 phr, preferably in amounts of 1 to 50 phr. Other mixture ingredients usually include crosslinking agents, such as sulfur, sulfur donors, or peroxides, fillers, such as carbon black and / or silica, processing aids, plasticizers, anti-aging agents, and optionally other additives (e.g., color pigments). In this regard, reference is made to the general state of rubber mixture technology.

[0023] In an advantageous embodiment, the elastomeric article can contain at least one additional embedded reinforcement. Embedded means that the reinforcement is not located on the surface. The embedded reinforcement can be in the form of a cord, felt, nonwoven, woven, braided, warp-knitted, or non-woven fabric.

[0024] If the elastomeric article is a drive belt, the embedded strength member is preferably in the form of cord, i.e. it is designed in a so-called cord construction.

[0025] The invention will now be explained in more detail with reference to comparative and exemplary embodiments, which are summarized in Tables 1 to 4.

[0026] A drive belt was manufactured for each belt and fitted with a corresponding textile overlay. The textile overlays are made of the material specified in the respective table.

[0027] The physical properties particularly important for a textile overlay on a drive belt that transmits torque through frictional engagement include, among other things, the degree of slippage occurring during power transmission and the coefficient of friction of the surface covered with the textile overlay. These also include parameters such as the misalignment of individual strands or the load bearing capacity of a drive pulley, which can be used to determine the occurrence of undesirable noise caused by the contact surface of the belt and the pulley. Since the objective of the present invention is to improve the wet properties of a product, the results of the physical tests under conditions of high ambient humidity are presented.

[0028] The physical tests include the determination of the coefficient of friction (CoF) under moisture according to SAE standard J2432, and measurements to evaluate noise and slip behavior.

[0029] The noise behavior is measured in three stages. What they have in common is that a belt is driven by a drive pulley at a speed n that exhibits a rotational irregularity of 10%.

[0030] In a dry measurement, a pulley A is shifted continuously relative to a pulley B by a maximum of 5 mm (corresponding to a 2.86° misalignment of the strand between A and B), and the angle is determined at which specific misalignment-related noises occur at the inlet to pulley B. In this measurement, no power transmission is present in the belt drive.

[0031] A wet measurement is performed under power output from a generator, which is adjusted based on the delivered current in steps of 10 A between a minimum of 30 A and a maximum of 120 A. At the beginning of each step, 20 ml / min of water is injected into the strand in front of the generator disc for 2 seconds in variant 1 and 300 ml / min for 10 seconds in variant 2.

[0032] In the slip-power measurement, the power transmitted by a frictional belt is determined via the resulting belt slip.

[0033] In the measurement underlying the test results, the described relationship is determined on a V-ribbed belt pulley with pulley diameters typical for generators in auxiliary units of passenger car engines and 120° wrap with continuous water injection. Table 1

[0034] The inventive textile overlay made of a lyocell knit demonstrates a visible improvement in the coefficient of friction (determined at 100% slip) under humid ambient conditions compared to a cotton and viscose knit of identical construction and similar basis weight. A higher coefficient of friction in this case means greater power transmission capacity. Table 2 Table 3

[0035] An improvement in the noise behavior of a lyocell textile overlay when wet during the drive is also evident (Tables 2 and 3). This advantage becomes particularly pronounced with a reduction in the basis weight of the textile (Table 3), which allows identical wet properties to be achieved with less material than with comparable cellulose-based cotton textiles. This further conserves resources.

[0036] Table 4 Table 5

[0037] Tables 4 and 5 show that a product obtained with the inventive

[0038] A V-ribbed belt with a textile cover can transmit significantly more power with the same slip than a belt of comparable construction with a textile cover made of viscose or cotton.

Claims

Patent claims 1. An article comprising an elastomeric base body based on at least one rubber mixture with a noise- and wear-resistant article surface provided with a textile overlay, characterized in that the textile overlay of the elastomeric article contains Lyocell fibers or consists entirely of Lyocell fibers.

2. Article according to claim 1, characterized in that the textile overlay has an average surface weight of between 70 g / m 2 and 350 g / m 2 owns.

3. Article according to claim 1 or 2, characterized in that the textile covering is a knitted fabric.

4. Article according to one of claims 1 to 3, characterized in that it also contains at least one embedded strength member.

5. Article according to one of claims 1 to 4, characterized in that it is a band, belt, strap, hose, air bellows, compensator or a multi-layer fabric.

6. Article according to claim 5, characterized in that the belt is a drive belt.

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