Conveyor belts, especially spindle tapes, with ultrasonically or laser cut lateral sides

Abstract

A conveyor belt, power transmission belt, or machine tape (1) having a longitudinal length L and two open end edges (6, 7), comprising: a) two parallel transverse edges (1a, 1b) extending longitudinally and separated from each other by a transverse width W; b) a first textile layer (2); c) a first coating layer (3); and, optionally, d) one or more through holes (5) extending through the belt through its entire thickness T, each formed by a perforation edge (5a), wherein i) the first textile layer (2) comprises fibers or filaments of a thermoplastic resin and / or the first coating layer (3) comprises a thermoplastic resin or a thermoplastic elastomer; and ii) the transverse edges (1a, 1b) are ultrasonically or laser cut, and / or the optional perforation edge (5a) is laser cut. The belt or tape has edges sealed by melting, may be edgeless by conventional edge joining, and may be used in hair-generating environments such as spindle tape.

Description

[Technical field]

[0001] The present invention relates to a belt, in particular a conveyor belt, machine tape, power transmission belt or spindle tape, and to a method for the manufacture thereof. [Background technology]

[0002] Conveyor belts, power transmission belts or machine tapes are generally cut into strips from a master sheet material having a larger width. Therefore, the most common cutting method has been knife cutting or punching. Such cutting methods have the disadvantage that the edges formed have cut filament ends, which make the edges more susceptible to fraying and collecting soil and moisture.

[0003] On the other hand, ultrasonic and laser cutting of edges is known in the art of conventional textiles, and the cut edge thus formed is at least partially melted, and the textile near the edge thus formed may have a thickness greater than the bulk of the textile, i.e., the textile tends to rise near the ultrasonically or laser cut edge.

[0004] Examples of literature relating to ultrasonic cutting of conventional fabrics are given below.

[0005] EP 0143513 A2 discloses ultrasonic cutting of uncoated, unimpregnated woven fabrics and an ultrasonic cutting and sealing means for cutting unwanted selvage from the fabric and sealing its longitudinal cut edges.

[0006] CH604930A5 discloses an ultrasonic cutting device for textile articles. The textile itself is not further specified. The document points out the problem of raised edges ("surepaisseurs") with thermally cut fused edges. The solution to this problem is to mount the ultrasonic cutter and the anvil on the same support ("support commun"). The device disclosed has two sonotrodes that each act on a single ultrasonic blade when cutting longitudinally. The ultrasonic frequency is disclosed to be 20 kHz and the advance speed of the ultrasonic cutter is not disclosed.

[0007] US 4,693,771A discloses an ultrasonic cutting method for edge removal in uncoated, unimpregnated woven fabrics, where 2-4 parallel warp or weft threads near the ultrasonic cutting edge are fused into a fused mass. The ultrasonic cutting edge tapers from the bulk of the fabric to the apex of the edge, which is achieved by using a specially designed anvil. The disclosed device has two ultrasonic sonotrodes each acting on a single ultrasonic blade. The document suggests a relationship between ultrasonic frequency and the travel speed of the ultrasonic cutter to achieve a well-sealed edge.

[0008] US 5,230,761 discloses the manufacture of waistbands in which a fabric having a thermoplastic finish is subjected to ultrasonic cutting along lines substantially parallel to the warp yarns. The finish is disclosed as a fabric impregnation since it is applied or spread on the fabric or web but is required to retain the fill and warp yarns. Seven knives may be used for every 7 to 9 inch horn width, producing a cut waistband having a transverse width within the range of 25.4 mm to 32.7 mm. This ultrasonic cutting process appears to produce raised edges.

[0009] The cutting of the above-mentioned master sheet material for conveyor belts may already be realized using ultrasound: the Applicant saw an advertisement on the Internet by the French company Decoup (an affiliate of Spoolex), offering such a master sheet cutting machine with multiple 20 kHz sonotrodes, each sonotrode acting on a single ultrasonic blade.

[0010] Furthermore, ultrasonic cutting of conveyor belts (transversely) to appropriate lengths appears to be known. CN104227782 discloses an ultrasonic cutting machine, in which a belt 10 is cut transversely by an ultrasonic cutter to different end faces. Hand-held ultrasonic cutters are available on the internet (e.g., on Alibaba) for such purposes.

[0011] Laser cutting of textiles is also known. Laser cutting is advertised as being suitable for obtaining lateral profiles in which the layers are fused together. EP1394316 discloses a multi-layered compound consisting of a fabric and a bottom adhesive layer, in particular of TPU. This bottom adhesive layer is heated so as to penetrate the fabric, after which the adhesive layer and optionally the fabric are pressed and flattened to form a plane. The fabric with the adhesive layer penetrated therein is said to be well suited for laser cutting or laser drilling, but does not disclose any laser cut products prepared therefrom by itself. The above mentioned US4,693,771A teaches against laser cutting as it is not effective, since it produces "blackened edges" and "produces little sealing so as not to provide durability against washing out of the cut edges."

[0012] A technique known in the conveyor belt art for forming non-fraying lateral belt edges is to weld a thermoplastic seam to an edge previously formed by unheated knife cutting or punching. Another method involves first forming the lateral edges of the belt by unheated knife cutting or punching, applying an additional layer of thermoplastic or thermoplastic elastomer of a slightly larger width to the belt so that there is a small protrusion of the thermoplastic or thermoplastic elastomer layer on either of the two edges, and bending and fusing the extra width of thermoplastic or thermoplastic elastomer over the cut edges. Both types of belts are available on the market and are advertised as having "non-fraying edges."

[0013] The term "sonotrode" is typically used for the ultrasonically driven support that holds one or more blades.

[0014] Many known ultrasonic textile cutting devices having multiple sonotrodes, where each sonotrode acts on only one cutting blade, do not appear to allow for close enough spacing of the cutting blades in the transverse direction to directly cut the conveyor belt or machine tape by the shear transverse direction of the sonotrode itself.

[0015] On the other hand, in the field of food processing, ultrasonic cutters are known in which one sonotrode drives several cutting blades arranged close to each other in the transverse direction and configured as a single tool. The ultrasonic cutter must, however, operate at the resonant frequency of the combination of sonotrode and cutting blade. Having several cutting blades increases the mass of this combination, increasing its inertia and lowering the resonant frequency. Furthermore, the cutting resistance that the sonotrode must overcome increases linearly with the number of cutting blades attached thereto, which may lead to the ultrasonic cutter becoming non-resonant. Industrial textiles are always cut by ultrasonic cutters that have one sonotrode operating on only one blade, i.e. the numerical ratio of sonotrode to cutting blade is 1:1.

[0016] The problem is to provide a belt of the above type that has unfrayed edges, maintains a similar or identical thickness near the edges to the thickness in the bulk of the belt, and is easier to manufacture than the above-mentioned prior art commercial belts that have "unfrayed edges." Summary of the Invention

[0017] [1] The present invention provides the following: 1. A belt having a longitudinal length L and open ends, or having a circumferential length L and no ends, said belt comprising: a) two parallel lateral edges (1a, 1b) each extending in said longitudinal direction or forming said perimeter and spaced apart from each other by a transverse width W; b) a first fabric layer; and c) a first coating layer; and, optionally, d) one or more through holes (5) passing through said belt through its entire thickness T, each of said through holes being defined by a hole edge (5a); Equipped with i) the first textile layer comprises fibers or filaments of a thermoplastic resin and / or the first coating layer comprises a thermoplastic resin or a thermoplastic elastomer; ii) the lateral edges are ultrasonically or laser cut and / or selective hole edges are laser cut; 2. The belt according to [1] above, wherein said first fabric layer comprises natural fibers or natural filaments. 3. The belt according to [1] or [2] above, wherein said first textile layer comprises fibers or filaments of polyester, in particular PET. 4. A belt according to any of the preceding items, wherein the first coating layer comprises TPU. 5. A belt according to any of the preceding items, wherein the transverse width is in the range of 10 to 25 mm, preferably 10 to 20 mm. 6. A belt according to any of the preceding items, comprising one or more through holes (5), the hole edges (5a) of the through holes (5) being laser cut. 7. A belt according to any of the preceding items, wherein the two lateral edges are ultrasonically or laser cut. 8. A belt according to any of the preceding items, having no through holes, and wherein the two lateral edges are ultrasonically or laser cut. 9. A belt according to any of the preceding items, having an open end, and having two end edges separated longitudinally by said longitudinal length L, and which are ultrasonically or laser cut. 10. A process for the simultaneous manufacture of N specimens of a belt according to any of the preceding items, in open-ended form, having ultrasonically cut lateral edges, N being an integer equal to or greater than 1, the process comprising: i) providing an essentially rectangular multi-layer sheet material having a layer structure as defined in one of [1] to [4] above, a longitudinal length greater than or equal to L, and a transverse width W0 greater than N×W; ii) passing the multi-layer sheet material through an ultrasonic cutter having at least one sonotrode and N+1 blades; wherein adjacent blades are separated from each other by a distance W such that each blade cuts into the sheet material to simultaneously cut the sheet material into N belt samples; iii) selectively forming, by laser cutting, one or more through holes (5) in each of the N belt samples; has. 11. The process of

[10] above, wherein the ultrasonic cutter has M sonotrodes, each i-th sonotrode having K i Drive the blades M and K i is an integer equal to or greater than 1, TIFF0007638285000001.tif1616112. The process of

[10] or

[11] above, wherein the blade is a circular disc blade (10) having a peripheral circular cutting surface (10a), and said circular disc blade (10) rolls over said multi-layer sheet material in ultrasonically cutting said belt sample. 13. Any of the processes [9] to

[12] above, wherein the multilayer sheet material is passed through an ultrasonic cutter at a travel speed in the range of 2 to 10 m / min, preferably 3 to 8 m / min, using ultrasonic waves of 30 kHz in each sonotrode and a power of 250 to 350 W per blade attached to that sonotrode. 14. A ring rotating frame with 2, 4 or 8 spindle tape drives with spindle tape belts according to [5] above. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of a spindle tape of the present invention. [Diagram 2] At 100x magnification, two photographs of the ultrasonically cut lateral edges of two different specimens of spindle tape constructed as shown in FIG. 1 are shown, the first specimen on the left and the second specimen on the right. [Diagram 3]Shown are two photographs of cross-sections of the same two spindle tape samples as in FIG. 2 at 150x magnification, the first sample on the left and the second sample on the right. [Figure 4] Photographs are shown of both a conventionally cut spindle tape (top) and the spindle tape of the present invention shown in FIG. 1 (bottom) after two months of use in a ring rotating frame. [Diagram 5] 2 shows a photograph of the laser cut lateral edges of a spindle tape of the present invention constructed as shown in FIG. 1. [Figure 6] A photograph of a cross section of the same sample of spindle tape in FIG. 5 is shown. [Figure 7] 1 shows a cross section of a preferred ultrasonic cutting blade. [Figure 8] 1 shows a desired ultrasonic cutting blade in the form of a circular disk for use in ultrasonic cutting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The belt or tape of the present invention has at least one ultrasonically or laser cut edge. As used herein without further explanation, "edge" means, for the purposes of the present invention, one or more of the following: a) A lateral edge of the belt or tape that extends essentially or completely parallel to the direction of travel of the belt or tape, preferably both lateral edges of the belt or tape. b) a terminal edge, which is one of the edges of the two belts or tapes spaced apart from one another in the longitudinal direction L, and which, when joined together, for example by heat and pressure and optionally by commonly used hot melt adhesives, renders the belt or tape endless; these terminal edges are preferably straight or in the form of serrated so-called "finger end" edges (see below). c) The edges of trough holes cut through the entire thickness of the belt. d) A combination of two or more of the above a), b), and c). Instead, individual types of edges are named herein where necessary or appropriate, particularly along the lines of a)-c) above.

[0020] Item [1] of the Summary of the Invention and feature ii) of claim 1 provide for the provision of one or more through holes (5) having at least lateral edges (1a, 1b) which are ultrasonically or laser cut or, if none of the lateral edges are ultrasonically or laser cut, having laser cut hole edges (5a).

[0021] Any ultrasonically cut or laser cut edge has subsequent structural features observable on the edge thus formed. a) the material of the first textile layer and / or the material of the first coating layer, to the extent that any of these layers comprise or consist of a thermoplastic or thermoplastic elastomer, appears to have resolidified after at least partial softening or melting, such that, as when cut by knife or punching, any fiber ends of the first textile layer will typically protrude from the cut edge as sharp points, whereas when cut by ultrasound or laser, due to said softening or melting and resolidification, any fiber ends of the first textile layer will appear blunt and at least partially embedded in the thermoplastic or thermoplastic elastomer from the first textile layer and / or the first coating layer; b) the porosity or fluffiness of the first fabric layer itself is reduced relative to the porosity or fluffiness of the fabric visible in said longitudinal cross-section.

[0022] Additionally, ultrasonic and laser cut edges differ from each other in that the latter exhibit a small amount of yellowish, dark, or nearly black deposit produced by scorching or carbonization of organic material at the newly formed edge by the heat of the laser.

[0023] Additionally, ultrasonic or laser cutting edges differ from each other and from conventional knife cutting edges in surface roughness, particularly when the surface roughness along the first fabric layer is measured.

[0024] In the case of longitudinal or end edges, the edge roughness is measured for the purposes of the present invention as a height profile z(x) along any contained layer, in particular the first textile layer, with focus change, which is a well-known optical height profile measurement method. The edge to be analyzed is considered to extend in the x (transverse) and y (vertical) directions, and the profile height is considered to extend in the z direction. If the edge to be analyzed is a transverse edge, the x direction coincides with the longitudinal belt direction, the y direction coincides with the belt thickness direction, and the z direction coincides with the belt cross direction. The surface cross section of the edge is photographed digitally in greyscale at a specific constant distance between the lens and the belt sample, at a specific focus. The same surface cross section of the edge is photographed again digitally in greyscale, but at a different focus, at the same distance between the lens and the belt sample, and the focus is moved to a specific focus by a fine focus shifting mechanism, for example a piezoelectric element, and the picture is taken when the center of the surface is in best focus. The center of the surface cross section is the measurement point x of one of the edges. i Point x i The central best-focus condition in may be obtained by a Laplace filter L. TIFF0007638285000002.tif11161In equation (2), l(m,n) is the grayscale intensity of the image pixel indicating the center of the surface, relative to which the distance (and therefore the height in the z direction) is measured. l(m,n+1), l(m+1,n), l(m,n-1) and l(m-1,n) are the grayscale intensities of the image pixels adjacent to the center pixel, respectively above (offset by +1 in the y direction), right (offset by +1 in the x direction), below (offset by -1 in the y direction) and left (offset by -1 in the x direction) relative to the center pixel. "~0" means that L is minimum or as close as possible to 0. In equation (2), l(m,n), l(m,n+1), l(m+1,n), l(m,n-1) and l(m-1,n) may preferably be replaced with corresponding 2x2 or 3x3 adjacent calculated averages, respectively, to reduce the noise sensitivity of the Laplace filter.

[0025] The most focused condition mentioned above is that at a specific measurement point x i When the center of the surface of the object is filled as, for example, by using Gauss's law of the lens, a photographic camera and x i The absolute distance z between the center of the surface part corresponding to i is converted to TIFF0007638285000003.tif13150 where o is the unknown distance between the central plane of the lens of the photo camera and the center of the surface. d is the known distance between the central plane of the lens of the photo camera and the CCD of the digital photo camera, which can be varied by the focus mechanism and is selected to obtain the best focus condition at the center of the surface. f is the known focal length of the lens of the photo camera (a constant specific to the lens). The Gaussian lens law is solved for the unknown o to find x i z i may, for example, be directly the same as o, or may be the sum of o and a constant arbitrarily chosen scale offset.

[0026] The above photographic process and distance evaluation is repeated at other measurement points along the edge (i.e., other surface portions). Each subsequent measurement point x(x) is then measured until the height profile z(x) is completed. i+1 is the previous measurement point x i are shifted in the x direction by a further, usually constant, offset.

[0027] Commercial instruments exist for such height profiling by focus variation.

[0028] This method makes it possible to measure height profiles along the edge of an individual layer in a belt or tape swatch of the invention, for example along the edge of a first textile layer. To measure such height profile z(x) along the edge of a layer, the belt or tape swatch is clamped between two rigid rectangular blocks with flat surfaces, so that the lateral or end edge to be measured is in intimate contact with one of the lateral sides of each of the two rectangular blocks. In such a clamped state, the belt or tape swatch may be advanced in the measurement (x) direction, usually by means of a motor-driven advancement support, with the lateral or end edge to be measured facing upwards. The result of the measurement is a one-dimensional transverse height profile z(x) of the edge as a function of the variable position x along the layer under consideration. By way of example, reference is made to the article "Optical method for measuring the surface roughness of processed carbon fiber reinforced plastic composites" in Journal of Composite Materials 0(0), pages 1-14 (2016). The measurement of the height profile z(x) is typically performed at a vertical height y which is half the thickness of the layer whose roughness is being measured.

[0029] The surface roughness of the longitudinal or terminal edges along the analyzed layer obtained by the above focus variations has been characterized using the height profile z(x) with the well-known parameters of standard deviation (s), skewness (Rsk) and kurtosis (Rku). TIFF0007638285000004.tif46161, where x iis the position of the i-th measurement point in the travel direction (x) along the edge relative to the start of the travel motion. i is the position x measured by the focus change described above. i is the height measured at the i-th measurement point in . N is the corresponding height z i (x i ) is the number of measurement points along the edge being measured. The sum is over all N measurement points. TIFF0007638285000005.tif16161 where all symbols are defined in equations (4a), (4b) and (4c) and all sums are over all measurement points.

[0030] The surface roughness of knife-cut, laser-cut, and ultrasonically cut transverse or end edges, particularly as measured along the first textile layer, measured as a height profile z(x), and characterized using Rsk and Rku, differ from one another. The absolute values ​​of Rsk and Rku of knife-cut, ultrasonically cut, and laser-cut transverse or end edges depend on the belt construction and cutting process characteristics, and absolute values ​​or ranges of absolute values ​​for the belt or tape of the present invention cannot be preliminarily stated. However, this is not necessary for the purposes of the present invention.

[0031] The Rsk according to equation (4b) above is expected to be best at the laser cut edge (the height profile z(x) tails only towards the inner bulk of the belt or tape), worse at the ultrasonic cut edge, and worst or closest to zero at the knife cut edge. This is because the temperature distribution from the outside (cutting edge) of the belt towards the inside (bulk) is highest in the laser cut, lower in the ultrasonic cut, and almost non-existent in the knife cut. Thus, by knife cutting a swatch of the inventive belt or tape such that the new knife cut reference edge runs parallel to the original lateral or end edge of the belt or tape swatch, measuring / analyzing both the original lateral or end edge of the belt or tape and the newly formed knife cut reference edge, and comparing their Rsk values ​​according to equation (4b) above, one can first identify whether the original lateral or end edge of the belt or tape swatch was knife cut, laser or ultrasonic cut. In the former case, there should be no statistically significant difference between the Rsk value of the original transverse or end edge and the newly formed knife cut reference edge, and in the latter case, the original transverse or end edge should have an Rsk value that is significantly better than the Rsk value of one of the newly formed knife cut reference edges.

[0032] The standard deviation, per equation (4a) above, for a laser cut lateral or end edge is expected to be lower than the s per equation (4a) above for either an ultrasonically or knife cut lateral or end edge. The Rku, per equation (4c) above, for a laser cut lateral or end edge is expected to be higher than the Rku for either an ultrasonically or knife cut lateral or end edge. This is because, of the three methods, the laser provides the sharpest and therefore smoothest edge. Secondly, one can identify whether the original transverse or end edge of the belt or tape specimen was laser cut or ultrasonically or knife cut by performing one or more reference cuts ultrasonically on the belt or tape specimen of the present invention under ultrasonic cutting conditions that result in a cut that most closely resembles the original transverse or end edge of the belt or tape specimen in appearance, with the newly cut reference edge running parallel to the original transverse or end edge of the belt or tape specimen, measuring / analyzing both the original transverse or end edge of the belt or tape and the newly formed cut reference edge, and comparing the s value according to equation (4a) or the Rku value according to equation (4c) above. In the former case, the s value of the original transverse or end edge should be lower than the s value of the newly ultrasonically cut reference edge, and the Rku value of the original transverse or end edge should be higher than the Rku value of the newly ultrasonically cut reference edge. In the latter case, the s or Rku value, respectively, of the original lateral or end edge should not be statistically significantly different or significantly larger than the s or Rku value, respectively, of the newly ultrasonically cut reference edge.

[0033] When the belt or tape of the invention has a woven first fabric layer, the above-mentioned reference edge for the identification of the transverse edge is preferably formed at an offset in the z-direction from said transverse edge, the offset being an integer multiple of the reciprocal of the spatial frequency ξ of the woven fabric in the z-direction, i.e. n / ξ, n being an integer equal to or greater than 1. Otherwise the comparison of the surface roughness of the transverse edge and the reference edge is meaningless. The location of such a further reference cut at an offset n / ξ from the corresponding transverse belt edge is shown by a dotted line in the lower part of FIG. 1.

[0034] At each end edge in the form of a serrated so-called "finger end" edge (see below), a corresponding further reference cutting edge is formed simply as a straight extension into the interior of the belt or tape. This extended further cut of the two serrated edges is indicated by oblique dotted lines in the lower part of FIG.

[0035] Any reference knife cutting edge may be formed using a trimmer, such as, for example, an IDEAL trimmer offered by Krug & Priester of Germany.

[0036] Any further reference cuts are shown by dashed reference cut lines at the bottom of FIG. 1, and will be understood to avoid any dimple holes present in the belt.

[0037] In the case of hole edges, edge roughness cannot be directly determined by the above methods. However, if the hole edge of interest shows signs of melted and resolidified material, it should be assumed that it has been laser cut. In applicant's experience, there is no other way to cut such holes with molten edges in the belt. In particular, ultrasonic cutting is not possible, since it forces the cut to have a very low curvature or to only produce straight cuts.

[0038] The belt or tape of the present invention has as necessary components a first textile layer (usually forming the traction layer of the belt or tape) and a first coating layer, the first textile layer comprising a thermoplastic resin, or the first coating layer comprising a thermoplastic resin or a thermoplastic elastomer, or the first textile layer comprising a thermoplastic resin and at the same time the first coating layer comprising a thermoplastic resin or a thermoplastic elastomer.

[0039] In one alternative, the first textile layer may be any layer containing fibers having a sheet-like configuration. Such a sheet-like layer essentially has the shape of a rectangular parallelepiped having a geometric length, a geometric width, and a geometric thickness, each of which is significantly greater than the geometric thickness. The textile may be a woven fabric (such as a plain or twill weave), a knitted fabric, or a non-woven fabric (such as a felt, fleece, etc.).

[0040] In a second alternative, the first textile layer may have or consist of an array of non-woven reinforcing yarns that run parallel to one another.

[0041] Desirably, the first fabric layer is a woven fabric or an array of non-woven reinforcing yarns.

[0042] The first fabric layer desirably forms or is configured in the traction layer of the belt. In order to make best use of the tensile properties of the fabric, when in the form of a woven fabric, it appears desirable to cut the fabric so that the warp (=pick) filaments of the fabric run parallel to the transverse edges and the weft (=fill) filaments of the fabric run transverse to the transverse edges.

[0043] The first textile layer may be entirely composed of either thermoplastic fibers or filaments, or alternatively, the first textile layer may have thermoplastic fibers or filaments in a mixture with natural fibers or filaments. Preferred thermoplastics are thermoplastic polyolefins, polyesters, especially aromatic polyesters such as PET, aliphatic polyamides, especially nylon, or aromatic polyamides such as aramids. The natural fibers or filaments are preferably selected from the group consisting of flax, jute, hemp, wool, cotton and ramie, and most preferably the natural fiber is cotton. When the first textile layer has a combination of thermoplastic fibers or filaments and natural fibers or filaments, the ratio of natural fibers or filaments to thermoplastic fibers or filaments is preferably in the range of 2:8 to 9:1.

[0044] The first coating layer comprises or preferably consists of a thermoplastic resin or a thermoplastic elastomer. Preferred thermoplastic resins for the first coating layer are thermoplastic polyolefins (such as polyethylene or polypropylene), substantially random ethylene / C 3-12-α-olefin copolymers (examples of α-olefins are 1-propene, 1-butene, 1-pentene, 1-hexene and 1-octene), thermoplastic polyamides, ethylene-vinyl acetate copolymers and poly(vinyl acetate). Homopolymers of vinyl chloride (PVC) or copolymers of vinyl chloride and vinylidene dichloride are also technically possible, but are undesirable in view of toxic gases that may be generated during laser or ultrasonic cutting. Desirable examples of thermoplastic elastomers for the cover layer are thermoplastic elastomeric block copolymers (styrenic block copolymers, in particular styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene / butylene-styrene, styrene-ethylene / propylene-styrene block copolymers), copolymers of hard blocks of medium density polyethylene and soft blocks of ethylene / α-olefin copolymers, thermoplastic polyurethanes (such as copolymers of polyester diols or polyether diols and diisocyanates), polyether / ester block amides, and thermoplastic elastomer ionomers.

[0045] Further preferred examples of materials for the first coating layer are thermoplastic elastomers, particularly TPU. Such suitable TPUs are generally obtainable by reacting a diisocyanate-containing hard block segment with a polyester diol soft block segment. The diisocyanate-containing hard block is obtainable by reacting a diisocyanate with a diol chain extender. The diisocyanate may be a pure compound or a mixture of diisocyanates. In one preferred embodiment, the diisocyanate is an aromatic diisocyanate, more preferably one of the isomeric 2,2'-, 2,4'-, or preferably 4,4'-diphenylmethane diisocyanates. Suitable diol chain extenders include aliphatic C2-C6-diols, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-propanediol, 2-methylpropanediol, 1,3-butanediol, 2,3-butanediol, 1,3-pentanediol, 1,2-hexanediol, 3-methylpentane-1,5-diol, or glycol ethers such as diethylene glycol, dipropylene glycol, tripropylene glycol, and amino alcohols such as ethanolamine, N-methyldiethanolamine, and the like. The polyester diol soft segments used desirably have a molecular weight between 500 and 2000. They may be prepared by reacting a diol with a dicarboxylic acid, or more conveniently by reacting a diol with a dimethyl ester of a dicarboxylic acid (transesterification) and boiling down with low-boiling methanol. The diol for the polyester diol is an aliphatic linear or branched C2-C8 diol, which may optionally contain a carbocyclic saturated C5-C6 ring. Thus, examples are ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 2-methylpropanediol, 3-methylpentane-1,5-diol, 1,6-hexanediol or cyclohexanedimethanol, and mixtures of these diols.The dicarboxylic acid for the polyester diol is an aliphatic linear or branched C2-C8 dicarboxylic acid. Thus, examples are oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid, or their dimethyl esters, sebacic acid, phthalic anhydride, tetrachlorophthalic anhydride, or dimethyl terephthalate, or mixtures thereof. The TPU is produced by reacting a diisocyanate-containing hard block segment with a polyester diol soft block segment with the respective free and reactive end groups. The most preferred TPUs are Lubrizol of the Esthene® type. More preferred TPUs are Esthene® 58277, Esthene® 54600, and Esthene® 54610. The most preferred TPU is Esthene® 58277. The TPU is preferably not blended or alloyed with other types of polymers.

[0046] Suitable thermoplastics or thermoplastic elastomers for the first coating layer, particularly TPU, desirably have a Shore A hardness in the range of 60 to 100, more desirably 70 to 95, at room temperature.

[0047] The first coating layer preferably comprises at least 80% by weight, more preferably at least 90% by weight, even more preferably at least 95% by weight, and most preferably 100% by weight, of a thermoplastic or thermoplastic elastomer material, as exemplified below, with these amounts suggested being based on the total weight of the first coating layer.

[0048] The thermoplastic resin in the first textile layer and the thermoplastic resin or thermoplastic elastomer in the first coating layer may be incompatible with each other. The term "incompatible" means that the blend of the thermoplastic resin in the first textile layer and the thermoplastic resin or thermoplastic elastomer in the first coating layer shows two distinct glass transition temperatures in differential scanning calorimetry (DSC). Ultrasonic or laser cutting leads to fusion of the two layers at the formed edge even in the absence of such compatibility. A specific example of an incompatible material pair is polyester (especially PET or PBT) in the first textile layer and thermoplastic polyurethane (TPU, especially the TPU mentioned above) in the first coating layer. Such textile layers and such coating layers may be fused to each other at the transverse edges using ultrasonic or laser cutting, even in the absence of processing aids such as homopolymers of acrylic esters and copolymers of acrylic esters with styrene, olefins and / or acrylonitrile.

[0049] It is desirable for the first textile layer and the first coating layer to be directly adjacent to each other or separated from each other only by an adhesive layer, which may comprise either a hot melt adhesive or a cross-linked adhesive such as a cross-linked polyurethane.

[0050] In its ultimate application, the orientation of the belt or tape is not important: the first fabric layer may face a drive pulley, may form a conveying surface along which goods are conveyed (if the belt is used as a conveyor belt), or may constitute a drive surface for an axle or pulley (e.g., if the belt is used for power transmission).

[0051] The belt or tape of the present invention may optionally have a further textile layer and one or more top coating layers. The composition of the further textile layer may be similar to that described above for the first textile layer. Optionally, the top coating layer may provide abrasion resistance, chemical resistance, antibacterial properties, moisture resistance, antistatic properties. Such top coating layers are conventional.

[0052] The top coating layer may be provided with an embossed profile to modify the coefficient of friction. In a preferred embodiment, the top coating layer is provided with two longitudinally extending portions having similar, preferably the same, transverse width, the two portions being adjacent to each other in the transverse direction such that the two portions exhibit different static coefficients of friction (COF) against steel or cardboard.

[0053] The belt of the invention may furthermore optionally have one or more through holes perforating the belt in its thickness direction. In this case, a preferred application of such a belt is a vacuum suction belt, which allows the suction of conveyed goods by vacuum suction onto the conveying surface of the belt. In this case, the belt preferably has a plurality of through holes, more preferably the through holes are arranged in a specific pattern, the distance between adjacent through holes being equal to or less than the dimensions of the conveyed goods, preferably significantly smaller, thus ensuring the vacuum suction of each of the goods placed on the belt. An exemplary rectangular pattern of a plurality of through holes 5 is shown in the lower part of FIG. 1. As shown in the lower part of FIG. 1, these through holes preferably have a circular cross section, in which case the diameter is preferably in the range of 1 to 3 mm. In the applicant's experience, laser cutting is the only possible way to generate through holes with partially melted or sealed hole edges.

[0054] The overall geometric thickness T of the belt or tape is typically selected to correspond to the overall geometric thickness of one of the corresponding prior art belt or tape types described above. In this specification, "geometric thickness" is understood to be the thickness measured with a thickness gauge at a defined overpressure of 0.2 bar (where overpressure means a pressure higher than the atmospheric pressure, which is usually about 1 bar). Preferably, the geometric thickness T of the front waterfall is in the range of 0.5 mm to 15 mm, more preferably 0.5 mm to 5 mm, even more preferably 0.5 mm to 2.5 mm.

[0055] The belt or tape of the present invention preferably has a certain amount of trapped gas. This may be in the first fabric layer and / or in the optional further fabric layers, i.e., these fabric layers may be partially or not completely impregnated. Alternatively or additionally, the first coating layer may be in the form of an open cell foam. Such encapsulation of gas is beneficial in ultrasonic or laser cutting, because in ultrasonic or laser cutting, the gas may be vented to the surrounding environment, thus compensating the effect of any volumetric expansion (bulging) of the belt or tape close to the transverse edge being ultrasonically or laser cut. In a preferred embodiment, the gas content [vol%] of the belt or tape is preferably in the range of 5% to 20%, and G is calculated according to equation (5): TIFF0007638285000006.tif36161 Here, V GeoB is the geometric volume of the rectangular parallelepiped belt or tape to be inspected, where for a rectangular parallelepiped belt or tape sample, the volume is obtained by measuring the geometric length, the geometric width and the geometric thickness by means of a thickness gauge under an overpressure of 0.2 bar as described above. V R is the volume of a reference sample having a defined known volume. TIFF0007638285000007.tif76 is the initial pressure increase with time (dP1 / dt at t=0) when a completely empty vacuum chamber is filled with helium using a helium permeation leak standard. TIFF0007638285000008.tif76 is the initial pressure increase with time (dP2 / dt at t=0) when a completely empty vacuum chamber containing a reference sample is filled with helium using a helium permeation leak standard. TIFF0007638285000009.tif76 is the initial pressure increase with time (dP3 / dt at t=0) when a completely empty vacuum chamber containing a rectangular belt sample is filled with helium using a helium permeation leak standard. TIFF0007638285000010.tif11161 and TIFF0007638285000011.tif76 is measured in a vacuum chamber at room temperature using a spinning rotor vacuum gauge.

[0056] The above volume percent determination at different pressures is known per se, see Setina J. and Erjavec B., "Volume Determination of Vacuum Vessels by Pressure Ramp Method", presented at the XIX IMEKO World Congress "Fundamentals and Applied Measurement Technologies", Lisbon, 6-11 September 2009, and references cited therein. The "initial pressure increase with time" may be taken from a small time interval that is not infinitesimal, such as ΔP / Δt instead of dP / dt, since the initial pressure increase is linear.

[0057] In a further preferred embodiment, which may be used alone or in combination with the preferred embodiment of gas filling described above, the textile is a woven fabric having warp and weft filaments, the warp filaments essentially not perfectly coincident on the one hand and running in the longitudinal direction of the belt. In particular, in cutting the transverse edges of the belt or tape by any method (conventional or according to the invention), it is not possible to guarantee that the transverse cut edges are perfectly parallel to the warp threads. Thus, it is not possible to guarantee that the warp threads run perfectly along the longitudinal direction of the belt or tape. If the transverse edges are knife cut (as in the prior art) and the warp threads do not run perfectly parallel to the transverse edges, there is a strong tendency for unraveling to occur, since the warp threads at the transverse edges may be damaged or cut apart to form an open end. This problem is exacerbated when the warp threads are in the form of multifilaments with multiple fine fibers (as is customary to improve the bendability of the belt or tape on pulleys with small radii). Belts with woven fabric and ultrasonically or laser cut transverse edges do not show unraveling even when the warp threads of the fabric are slightly skewed with respect to the longitudinal direction of the belt, for example by an angle of 0.1 to 1°, or 0.1 to 0.5°. Here, the term "skew" may mean that the average direction of the warp threads averaged over the entire length of the belt is skewed by the indicated angle. Also, "skew" may mean that the local direction of the warp threads in, for example, a 2-5 cm longitudinal portion of the belt or tape may have such an angle with respect to the longitudinal direction of the belt or tape.

[0058] The belt or tape according to the invention may be in an open-ended configuration, having two end edges 6, 7 as shown in the lower part of FIG. 1, which may be joined to form a corresponding endless configuration (see below). In this open-ended configuration, the configuration has a longitudinal length L, whereas in the corresponding endless configuration, it has a circumferential length L. If the two end edges are straight, the belt has the shape of an elongated strip, preferably that of an elongated rectangle or parallelogram, when viewed from above. However, for the purposes of joining the ends, it is preferred that the two end edges have a regular sawtooth shape, each end edge having alternating identical teeth and identical recesses, so that, in joining the ends, each tooth of one end edge fits snugly into a corresponding recess of the other end edge and vice versa. This end joining method is generally referred to as the "finger end" joining method and is desired for the purposes of the present invention. In the case of such sawtooth end edges, the open-ended belt of the present invention has a top view similar to that shown in the lower part of FIG. 1.

[0059] The belts or tapes of the invention, whether open or without ends, have a width W that is generally constant and typical for belts for industrial applications. In power transmission belts and machine tapes, the width W may desirably range from 10 mm to 25 mm, more desirably from 10 mm to 20 mm, which are the preferred applications for machine tapes of the invention (see below). The lateral edges are desirably straight, parallel to one another, and separated from one another in the transverse (z) direction by a constant width W.

[0060] The longitudinal length L of an open-ended belt or tape according to the invention, or the perimeter L of an open-ended belt or tape according to the invention, is understood as the quotient obtained by dividing the geometric surface area of ​​the belt or tape by a certain width W. The geometric surface is determined by measuring the weight of the belt or tape and dividing this weight by, for example, 0.01 m 2For open-ended or endless belts or tapes, the longitudinal length L is generally available, with similar results within experimental error, as the length of one lateral edge (of a rectangle) or the average of the lengths of two lateral edges (of a parallelogram) for the above-described desirable open-ended belts or tapes having a stretched rectangular or parallelogram shape with straight end edges. For the above-described desirable open-ended belts or tapes having serrated "finger end" end edges, the longitudinal length L is also available, with similar results within experimental error, as the longitudinal distance from half the height of the teeth of one end edge 6 to half the height of the teeth of the other end edge 7, as shown in the lower part of FIG. 1.

[0061] In another preferred embodiment of the invention, the belt or tape has no ends. In this undone form, the belt or tape has a perimeter L that essentially corresponds to the longitudinal length L of the open-ended belt or tape from which it is formed. The perimeter L may extend along the "pitch line" or "neutral line" of the undone belt, i.e., the inner line of the undone belt that does not change length when the undone belt is in use. In this specification, the term "perimeter" refers to both the physical peripheral lateral edges of the undone belt, as in the prior art, and the length L associated with such peripheral lateral edges. End joining to render the belt or tape undone is usually performed as a final step, and is customarily performed using a hot press and optionally a hot melt adhesive.

[0062] In the above cases, the ratio of longitudinal length L (or circumference L) to width W is preferably in the range of 1:100 to 1:2000, preferably 1:150 to 1:2000, and more preferably 1:200 to 1:2000.

[0063] Any belts and tapes of the present invention are desirably in the form of so-called "flat belts", i.e., belts or tapes that do not have transversely extending teeth and associated recesses on their upper and lower surfaces and / or do not have longitudinally extending grooves and associated ridges on their upper and lower surfaces.

[0064] The belts or tapes of the present invention have knife cut edges and may be used in any application where a corresponding conventional conveyor belt, power transmission belt or machine tape with the same layer structure is employed. If all edges involved are ultrasonically or laser cut, the belts or tapes are particularly applicable in any application where particulate dust or fiber hairs may be formed in use and contaminate the edges. Such belts or tapes of the present invention, by virtue of their melt sealing, are able to withstand the accumulation of such dust or hairs at or within the edges. Due to this advantageous property, such belts or tapes of the present invention may be used in environments that generate such dust or hairs even in the absence of antistatic facilities, such as, for example, coatings with embedded antistatic particles or fabrics with antistatic filaments. A further application of the belts or tapes of the present invention with all edges ultrasonically or laser cut is in environments where solvents such as acetone contaminate the belts or tapes. It has been observed that sealing the edges by partial melting inhibits such solvents from penetrating into the belts or tapes. An example of such an application is the paint or cosmetic industry or chemical plants where such solvents are manufactured and packaged.

[0065] A further application of the belts or tapes of the present invention having all edges ultrasonically or laser cut is in environments where mold or bacteria may contaminate the belt or tape. It has been observed that sealing the edges by partial melting inhibits the ingress of bacteria into the belt or tape. An example of such an application is in the food industry.

[0066] However, a preferred application is the use of the machine tape of the invention as a spindle tape. Spindle tapes are typically used in a type of ring rotating frame in which the spindle is driven by an open-ended tape loop formed by the spindle tape. This use is one in which hairs are formed during the operation. There are variants in which 2, 4 or 8 spindles are driven by one spindle tape, and the spindle tape of the invention is suitable for all of them. It has been found that the spindle tape of the invention does not accumulate any frayed hairs at the ultrasonically or laser cut edges even after prolonged use (see the examples and related figures).

[0067] In the upper part of FIG. 1, a schematic diagram of a belt or tape 1 of the invention is shown. The belt or tape has a first textile layer 2 and a first coating layer 3. The first textile layer 2 has a woven fabric of mixed PET / cotton filaments (50:50). One of the ultrasonically cut or laser cut transverse edges is indicated by reference 1a. The first textile layer 2 and the first coating layer 3 are bonded to each other by an adhesive layer 4 with crosslinked polyurethane. Furthermore, the belt or tape has selective through holes (one of which is indicated by reference 5) that perforate it. Each through hole 5 is formed by a laser cut hole edge 5a. The lower part of FIG. 1 shows a top view of a belt or tape of the invention with a plurality of through holes (only one of which is indicated by reference 5).

[0068] The cutting of the edges of the belt or tape of the present invention is described in detail below.

[0069] The ultrasonic cutting process is used for cutting either lateral edges or end edges where one or more belts are cut from a wider multi-layer sheet material (master tape).

[0070] Generally, ultrasonic cutting is essentially adiabatic. That is, any heat introduced by the ultrasonic cutter at a particular location of the edge to be cut essentially remains at that location, at least for the time the ultrasonic cutting blade is at that location, unless it is removed by any explicit cooling means, such as air or inert gas, sprayed or otherwise applied directly to that location. Thus, when used in the process of the present invention, the ultrasonic cutter does not have, employ or require any explicit cooling means, such as ducts, pipes, hoses, nozzles or fans, that deliver cooling means, such as air or inert gas, directly to the cutting area at the surface of the belt or tape. However, it will be understood that in the case of ultrasonic cutting, the blade and / or horn and / or sonotrode may be cooled by such cooling means.

[0071] The ultrasonic waves are preferably in the frequency range of 20 kHz to 100 kHz, more preferably 20 kHz to 40 kHz, and most preferably about 30 kHz, which is related to the resonant frequency at which the sonotrode in combination with the cutting blade or blades normally operates, a constant specific to the sonotrode and cutting blade combination.

[0072] The longitudinal amplitude of the ultrasonic vibrations (in the cutting direction) is preferably in the range of 10 μm to 100 μm, more preferably in the range of 15 μm to 60 μm.

[0073] However, a certain amount of energy (Joule / m2) is required per unit surface area of ​​the side of the horizontal belt or tape. 2The ultrasonic power and blade travel speed are selected to provide a maximum cutting edge thickness of 100 nm, so that the cut edge does not significantly increase in thickness relative to the bulk thickness of the belt or tape, while there is sufficient heating for the cut edge to be sealed by the molten thermoplastic or thermoplastic elastomer material from the fabric in the traction layer or other layers coated or laminated to the traction layer. At a frequency of 30 kHz, it is desirable to use 200 to 400 watts of power per cutting blade, and more desirably 250 to 350 watts. Lower frequencies may require more power per cutting blade, for example, a reduction in frequency from 40 kHz to 20 kHz (by a factor of two) may require four times the power per cutting blade.

[0074] To achieve both sufficient edge sealing and no build-up in a given belt or tape type, for a given cutting direction (e.g. parallel to the warp yarns of the woven first fabric or parallel to the weft yarns of the woven first fabric), for a given sonotrode / blade resonant frequency, and for a given type and number of blades driven by the sonotrode, there is an optimum advance speed v [m / min] of the blade relative to the sheet material, which advance speed is approximately proportional to the nominal power P [watts] of the ultrasonic cutter employed. TIFF0007638285000012.tif16161

[0075] The constant (constant 1) in equation (6) is found by varying the advance speed v for a particular and fixed combination of sheet material, sonotrode / blade and ultrasonic frequency and observing the v at which both of the above objectives are achieved. The constant in equation (6) is found by dividing the optimum value v by the ultrasonic power P used.

[0076] Figures 2 and 3 show the effect of varying the blade advance speed while keeping other process parameters constant. The left photograph in Figure 2 and the left photograph in Figure 3 respectively show the ultrasonically cut lateral profile 1a and cross section of the spindle tape with the structure shown in Figure 1 when the blade advance speed v is slightly too large. The left photograph in Figure 2 shows sufficient lateral edge sealing. The white cloth and black TPU from the first coating layer are extensively smeared and melted together. However, the left photograph in Figure 3 shows a bulge near the lateral edge on the right side. The tape bulk has a thickness of a little more than 0.6 mm and increases to a thickness of a little more than 0.8 mm near the lateral edge. Regardless of this, the spindle tape is suitable for practical use. On the other hand, the right photograph in Figure 2 and the right photograph in Figure 3 respectively show the ultrasonically cut lateral profile 1a and cross section of the spindle tape with the structure shown in Figure 1 when the blade advance speed v is obviously too small. The right photo in Figure 2 shows poor lateral edge sealing. The white fabric and black TPU from the first coating layer are essentially not smeared and are not fused together. The right photo in Figure 3 shows that there is no protuberance on the right side and there is a small amount of reduction in thickness near the lateral ultrasonic cut edge. With poor edge sealing, this spindle tape sample is expected to perform poorly in use.

[0077] It is desirable for the cutting blade travel speed v to be below a critical travel speed at which the cutting resistance increases as the ultrasonic cutter goes off resonance, particularly detectable by a clear drop in vibration amplitude. There are ultrasonic cutters on the market that monitor vibration frequency and amplitude and automatically increase the applied power when the cutter goes off resonance. For the belt type described above, suitable optimum travel speeds v are often or typically within the range of 2 m / min to 10 m / min, preferably 3 m / min to 8 m / min, more preferably 5 m / min to 7 m / min, at 250 to 350 watts per blade.

[0078] Once the constants in equation (6) are known, for the same specific and fixed combination of sheet material, sonotrode / blade, and ultrasonic frequency, equation (6) allows one to approximately predict what travel speed v should be selected for a particular ultrasonic power.

[0079] The cutting blade preferably has Cs symmetry, the plane of symmetry being parallel to the forward movement direction of the blade relative to the belt or tape to be cut and parallel to the direction of long-acoustic vibration. In this way, an equal power flow is ensured towards both sides of the blade, thus forming two lateral edges that are ultrasonically cut in the same way. The cutting surfaces 8a, 8b of the blade 8 are preferably planar and preferably lie at 60° to 100°, preferably 70 to 80°, relative to each other, as shown in FIG. 7. More preferably, the blade has the form of a disk 10 with a circumferential circular cutting surface (as shown in FIG. 8). One of the circular circumferential cutting surfaces has the reference 10a. Such a disk-shaped blade 10 is rotatably mounted on a sonotrode 9 on an axle 11. During ultrasonic cutting at a travel speed v, such a disk-shaped blade 10 rolls simultaneously over the belt material 12 so as to cut into one or more belts or tapes. The desirable features regarding the cutting surfaces and the respective angles described above for the blade in general also apply to such a rotatable disk-shaped blade 10.

[0080] In a preferred process embodiment, multiple belt or tape samples are cut simultaneously from a sheet material (master tape) using multiple blades. In this embodiment, the sheet material is cut by an ultrasonic cutter having a width W0 preferably of 400 to 500 mm, preferably 3 to 4 sonotrodes each driving 10 to 12 blades, the ultrasonic frequency is about 30 kHz, the power of each sonotrode is preferably in the range of 300 to 400 watts, and the travel speed is preferably 3 to 5 m / min, it being understood that the above considerations regarding travel speed are taken into account.

[0081] The sonotrode 9 is preferably side slitting, i.e. preferably cutting by a sawing action rather than a punching action. In this preferred cutting direction, in at least one variant, it has a straight transverse cutting edge tapering towards the blade tip at an angle in the range of 5 to 45° to the direction of the ultrasonic vibrations. In an alternative preferred embodiment of the side slitting / sawing action, the blade may have a downwardly facing cutting edge and may have the shape of a generally circular or elliptical arc.

[0082] The direction of the ultrasonic vibrations, and therefore the direction of the blade vibration in the cut, is preferably perpendicular to the surface of the sheet material being cut into the belt when viewed in the cutting direction, and is slightly inclined to the normal to the belt surface when viewed transversely to the cutting direction. The angle of inclination to the normal to the sheet material surface is preferably 5° to 40°, more preferably 20 to 40°, and most preferably about 30°.

[0083] The ultrasonic cutting device, including the sonotrode and the blade, is a conventional device, preferably one typically used in the fields of food slicing or clothing cutting.

[0084] The laser cutting process may be used at either edge of the belt or tape. In the laser cutting process, the heat introduced by the laser cutter is desirably removed from the cut area by cooling means that delivers air or an inert gas or the like directly to the cut area. Thus, the laser cutter used in the process of the present invention desirably has and employs distinct cooling means such as ducts, pipes, hoses, nozzles, or fans that deliver cooling means such as air or an inert gas directly to the cut zone of the belt or tape surface.

[0085] In order to achieve both adequate edge sealing and no build-up in laser cutting for a given belt or tape type, for a given cutting direction (e.g., parallel to the warp yarns of the woven first fabric or parallel to the weft yarns of the woven first fabric), for a given belt or tape thickness d [m], and for a given laser type, the optimum advance speed v [m / min] of the laser relative to the sheet material is approximately proportional to the intensity of the laser beam employed. TIFF0007638285000013.tif16161

[0086] The constant (constant2) in equation (7) is found by varying the travel speed v for a fixed laser intensity and fixed cutting direction and observing which v achieves both of the above objectives. This is a one-parameter variation that is within the ability of one skilled in the art. Dividing the optimal value by the laser intensity used gives the constant in equation (7).

[0087] Similarly, if the constants in equation (7) are known, then for the same belt or tape type and cutting direction, equation (7) can roughly predict what advance speed v should be selected at a particular laser intensity.

[0088] The laser employed is preferably a CO2 (infrared) laser. More preferably, it is a "slab" CO2 laser, and even more preferably, the two reflecting mirrors are shaped to provide an unrestricted directional instability in the resonator. The resonator of the slab laser is preferably made of a ceramic selected from the group consisting of Al2O3, BeO, and AlN. The excitation electrodes are outside the ceramic resonator to allow better cooling at the electrodes. Using a ceramic resonator instead of a metal (aluminum) resonator could improve the shape of the cut edge.

[0089] A desirable power range for the laser is 100 to 200 watts.

[0090] Figures 5 and 6 show photographs of the laser cut lateral edges and cross section, respectively, of a sample spindle tape of the present invention constructed as shown at the top of Figure 1. Essentially complete bleeding of the white fabric and black TPU due to melting of the edge material is evident in Figure 5. Figure 6, on the other hand, shows no rise of the tape near the lateral edges.

[0091] The invention is illustrated by the following non-limiting examples.

[0092] (Example) Example 1: Simultaneous production of multiple spindle tapes from a master tape by ultrasonic cutting of the lateral edges

[0093] It has a layer structure similar to that shown in the applicant's commercial spindle tape D-8, and has a width of 500 mm, a thickness of 0.7 mm, and a strength of 0.7 kg / m 2 A master tape of weight per unit area was used as the initial multi-layer sheet material.

[0094] This master tape was attached to the feeding roll of a commercial multi-blade ultrasonic cutter (Fabotex, TCU400, with 4 sonotrodes and a total of 40 blades, operating at 30 kHz and a total of 1500 watts). The blades were spaced 12.7 mm apart from each other. The master tape was passed through the ultrasonic cutter at a travel speed of 3 m / min. 39 samples of the spindle tape of the invention, each with a width of 12.7 mm, were obtained simultaneously. A few millimeters of the edge from each border of the master tape were discarded.

[0095] Example 2: Field testing of conventional spindle tape (transverse edge knife cut) and the inventive spindle tape (transverse edge ultrasonic cut)

[0096] A ring rotating frame with four spindle tape drives was fitted with either a spindle tape swatch prepared according to the procedure of Example 1, or a reference spindle swatch similarly constructed, except that no further action was taken against hair contamination of the lateral edges, and the lateral edges were simply knife cut. In each case, the ring rotating frame was operated for two months, with the spindles operating at at least 18,000 rpm. After two months of service time, the spindle tapes were inspected for hair contamination. Figure 4 shows photographs of the two types of spindle tapes. The top photograph shows the condition of the reference spindle tape. The edges have a noticeable amount of white hairs protruding perpendicularly from the edge. In contrast, the spindle tape of the present invention is completely free of hairs at the edges (as shown in the bottom photograph of Figure 4).

Claims

1. A tape having two end edges (6, 7) and an open end, a longitudinal length L in a longitudinal direction, suitable for a conveyor belt (1), a power transmission belt (1) or a machine tape (1), said tape comprising: a) two parallel lateral edges (1a, 1b) each extending in said longitudinal direction and spaced apart from each other by a transverse width W; b) a first textile layer (2); and c) a first coating layer (3) made of TPU; Equipped with i) the first textile layer (2) comprises fibers or filaments of a thermoplastic resin and the first coating layer (3) comprises a thermoplastic resin or a thermoplastic elastomer; ii) A tape, wherein said lateral edges (1a, 1b) are ultrasonically or laser cut.

2. 2. The tape according to claim 1, wherein the first textile layer (2) comprises natural fibres or natural filaments.

3. 3. Tape according to claim 1 or 2, wherein the first textile layer (2) comprises fibres or filaments of polyester, in particular PET.

4. 4. A tape according to any one of claims 1 to 3, wherein the transverse width W is in the range 10 to 25 mm, preferably 10 to 20 mm.

5. Having one or more through holes (5) having hole edges (5a), 5. Tape according to any one of the preceding claims, wherein the hole edges (5a) of the through holes (5) are laser cut.

6. 6. Tape according to any one of the preceding claims, wherein the two lateral edges (1a, 1b) are ultrasonically cut.

7. No through hole, 5. Tape according to any one of claims 1 to 4, wherein the two lateral edges (1a, 1b) are ultrasonically cut.

8. 6. Tape according to any one of claims 1 to 5, wherein the two end edges (6, 7) separated from each other in the longitudinal direction by the longitudinal length L are laser cut.

9. 9. The tape of claim 1, wherein the ratio of the width W to the longitudinal length L is in the range of 1:100 to 1:2000.

10. 10. An endless conveyor belt (1) obtained by endlessing a tape according to any one of claims 1 to 9 suitable for a conveyor belt, or A power transmission belt (1) obtained by blunting a tape according to any one of claims 1 to 4 or claims 6 to 8 suitable for a power transmission belt, or A machine tape (1) obtained by blunting a tape according to any one of claims 1 to 4 or claims 6 to 8 suitable for machine tapes, A conveyor belt, power transmission belt or machine tape, the endless form being obtained by joining two of said end edges (6, 7).

11. A process for the simultaneous production of N samples of a tape with ultrasonically cut lateral edges (1a, 1b) according to any one of claims 1 to 9, comprising: N is an integer of 1 or more, The process comprises: i) a layer structure as defined in any one of claims 1 to 3, a longitudinal length equal to or greater than L, and a transverse width W greater than N×W; ０ providing an essentially rectangular multi-layer sheet material having a ii) passing said multi-layer sheet material through an ultrasonic cutter having at least one sonotrode (9) and N+1 blades (8, 10); iii) selectively forming, by laser cutting, one or more through holes (5) in each of the N specimens; having Adjacent blades are separated from each other by a distance W such that each blade (8, 10) cuts into the sheet material so as to simultaneously cut the sheet material into N specimens.

12. The ultrasonic cutter has M ultrasonic sonotrodes, each i-th sonotrode having K ｉ Drive the blades M and each K ｉ is an integer equal to or greater than 1, The process of claim 11 , wherein

13. The blade is a circular disk blade (10) having a peripheral circular cutting surface (10a), 13. The process of claim 11 or 12, wherein the circular disc blade (10) rolls over the multi-layer sheet material in ultrasonically cutting the sample.

14. The multi-layer sheet material is passed through the ultrasonic cutter at a travelling speed in the range of from 2 to 10 m / min, preferably from 3 to 8 m / min; 14. The process according to any one of claims 11 to 13, using in each sonotrode ultrasound of 30 kHz and a power of 250 to 350 W per blade attached to the sonotrode.

15. A ring rotating frame having 2, 4 or 8 spindle tape drives, having as a spindle tape an endless machine tape obtained by endlessing a tape according to any one of claims 1 to 4 or claims 6 to 8 suitable for a machine tape, The endless form is obtained by joining the two end edges (6, 7), A ring rotating frame, wherein said transverse width W is in the range of 10 to 25 mm, preferably 10 to 20 mm.

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