Conveyor belt with ultrasonic or laser cut side edges, in particular spool belt

Abstract

A conveyor, power transmission or machine belt (1) which is open ended and has two end edges (6, 7) and a longitudinal length L in a longitudinal direction, comprising: a) two parallel lateral edges (1a, 1b) each extending in the longitudinal direction and separated from each other by a transverse width (W); b) a first fabric layer (2); c) a first coating layer (3); and optionally d) one or more through holes (5) through the overall thickness (T) of the belt, each of the through holes (5) being formed by a hole edge (5a), characterized in that i) the first fabric layer (2) comprises fibers or filaments of a thermoplastic and / or the first coating layer (3) comprises a thermoplastic or a thermoplastic elastomer; and ii) the lateral edges (1a, 1b) are ultrasonic or laser cuts and / or the optional hole edges (5a) are laser cuts. The belt or band has melt sealed edges, can be made into a loop by conventional end joining, and can be used in environments where lint is produced, such as a spool belt.

Description

TECHNICAL FIELD

[0001] The present invention relates to a belt, in particular a conveyor belt, a machine belt, a power transmission belt or a spool belt, and a method for its manufacture. BACKGROUND

[0002] Conveyor belts, power transmission belts or machine belts are usually cut from a main sheet material which is wide. The most common cutting techniques are therefore knife cutting or stamping. The disadvantage of these cutting techniques is that the edges produced in this way have cut thread ends which can lead to the edges wearing easily and picking up dirt and moisture.

[0003] On the other hand, ultrasonic cutting and laser cutting of edges are known in the field of flat woven textiles. It has been observed that the cut edges produced in this way are at least partially melted and that the textile can have a greater thickness in the vicinity of the edge thus formed than at the main body of the textile, that is to say that the textile tends to swell in the vicinity of such an ultrasonic or laser cut edge.

[0004] Publications relating to ultrasonic cutting of flat woven textiles are for example:

[0005] EP 0 143 513 A2 discloses ultrasonic cutting of uncoated and unimpregnated textile fabrics and an ultrasonic cutting and sealing device for cutting off unwanted selvedges from the fabric and sealing their longitudinal cut edges.

[0006] CH 604 930 A5 discloses an ultrasonic cutting device for textile articles. The textile itself is not further specified. The publication mentions the problem of swollen edges ("surépaisseurs") with hot cutting, of melted edges. Its solution to this problem is that the ultrasonic cutter and anvil should be mounted on the same support ("common support"). The disclosed device has two welding heads, i.e. ultrasonic generators or ultrasonic welding electrodes, each acting on a single ultrasonic blade, when cutting in the longitudinal direction. The ultrasonic frequency is described as 20 kHz; the advance speed of the ultrasonic cutter is not disclosed.

[0007] US 4,693,771 A discloses an ultrasonic cutting method for removing selvedges from uncoated and unimpregnated woven textile fabrics, in which 2-4 parallel warp or weft yarns close to the ultrasonic cut edge are fused into a melt. The ultrasonic cut edge tapers from the main body of the fabric towards the apex of the edge, which is achieved by using a specially designed anvil. The disclosed device has two ultrasonic welding heads, each acting on a single ultrasonic blade. This publication implies a relationship between the ultrasonic frequency and the advance speed of the ultrasonic cutter in order to achieve a sufficiently sealed edge.

[0008] US 5,230,761 discloses the manufacture of waistbands in which a fabric having a thermoplastic surface treatment is ultrasonically cut along a line approximately parallel to the warp yarns. The surface treatment is described as being applied or coated onto the fabric or web, but is also required to hold the weft and warp yarns together, so it is disclosed as a fabric impregnation. Seven cuts can be used per 7 to 9 inch angular width, cutting out waistbands with a lateral width in the range 25.4 mm to 32.7 mm. This ultrasonic cutting process apparently results in raised edges.

[0009] The cutting of the above-mentioned master sheet material for conveyor belts can also have been done using ultrasonics. The Applicant has noticed on the internet an advertisement by the French company Decoup (a subsidiary of Spoolex) according to which they offer such master sheet cutting machines with a plurality of 20 kHz sonotrodes, each of which acts on a single ultrasonic blade.

[0010] Furthermore, it appears to be known to ultrasonically cut conveyor belts into suitable lengths (i.e. in the lateral direction). CN 104227782 discloses an ultrasonic cutter in which a belt 10 is cut transversely into different end faces with an ultrasonic cutter. Handheld ultrasonic cutters for this purpose are available on the internet (e.g. on Alibaba).

[0011] Laser cutting of textiles is also known. Laser cutting has been advertised as being suitable to obtain side edges in which the various layers are melted together. EP 1 394 316 discloses a layered compound consisting of a fabric and a bottom adhesive layer (in particular consisting of TPU). This bottom adhesive layer is heated to cause it to penetrate into the textile, whereafter the adhesive layer and optionally also the textile are pressed and flattened to form a flat surface. The fabric in which the adhesive has penetrated is said to be very suitable for laser cutting or laser perforation, but the publication itself does not disclose any laser cut products made therefrom. The above-mentioned US 4,693,771 A provides a contrary teaching to laser cutting, on the grounds that laser cutting results in "black edges" and "if any seal is present, even a small one, results in the cut edge not having wash durability".

[0012] Known techniques in the field of conveyor belts to form a wear-free lateral belt edge have welded a seam of thermoplastic material to an edge previously formed by cold knife cutting or stamping. Another such technique is to first form the lateral edge of the belt by cold knife cutting or stamping, and then to apply a further layer of thermoplastic or thermoplastic elastomer to the belt which is slightly wider, so that the layer of thermoplastic or thermoplastic elastomer has a slight overhang on either of the two edges, and the excess width of the layer of thermoplastic or thermoplastic elastomer is bent over the cut edge and fused there. Both types of belt are marketed and advertised as having "wear-free edges".

[0013] The term "horn" is generally used to keep the ultrasonic drive support of one or more cutting blades.

[0014] It appears that most known ultrasonic textile cutting devices have multiple horns, each of which acts on only one cutting blade, not allowing the cutting blades to reach a sufficiently close spacing in the transverse direction, such as to cut a conveyor belt or machine belt directly, because the transverse dimension of the horn itself is large.

[0015] On the other hand, in the food processing sector, ultrasonic cutters are known in which one horn drives multiple cutting blades arranged close to each other in the transverse direction and configured as a single tool. However, the ultrasonic cutter must operate at the resonant frequency of the combination of the horn and the cutting blades. Having multiple cutting blades increases the weight of the combination and therefore its inertia, which lowers the resonant frequency. In addition, the cutting resistance that the horn must overcome increases in a linear manner with the number of cutting blades attached to it, which can also cause the ultrasonic cutter to exit resonance. As a result, industrial textiles are always cut with ultrasonic cutters having one horn operating on only one blade, i.e. with a horn-to-cutting blade ratio of 1:1.

[0016] There is a problem of providing a belt of the aforementioned type having a wear-free edge that maintains a thickness near the edge similar to or even equal to the thickness at the body of the belt and that is easier to produce than the commercial belts with "wear-free edge" of the above-mentioned prior art. SUMMARY

[0017] The present invention provides:

[0018] 1. A belt, open-ended and having a longitudinal length L in a longitudinal direction or having a circumference L, the belt comprising:

[0019] a) two parallel lateral edges (la, lb) extending in the longitudinal direction or forming the circumference and separated from each other by a transverse width W;

[0020] b) a first fabric layer;

[0021] c) a first coating layer; and optionally

[0022] d) one or more through holes (5) through the overall thickness T of the belt, each of the through holes (5) being formed by a hole edge (5a),

[0023] characterized in that

[0024] i) the first fabric layer comprises fibers or filaments of thermoplastic and / or the first coating layer comprises a thermoplastic or a thermoplastic elastomer; and

[0025] ii) the lateral edges are ultrasonic or laser cuts, and / or the optional hole edges are laser cuts.

[0026] 2. The tape according to the preceding [1], wherein the first fabric layer comprises natural fibers or natural filaments.

[0027] 3. The tape according to the preceding [1] or [2], wherein the first fabric layer comprises fibers or filaments of polyester, in particular PET.

[0028] 4. The tape according to any of the preceding items, wherein the first coating layer consists of TPU.

[0029] 5. The tape according to any of the preceding items, wherein the transverse width is in the range of 10 mm to 25 mm, preferably 10 mm to 20 mm.

[0030] 6. The tape (1) according to any of the preceding items, comprising one or more of the through holes (5), and the hole edges (5a) of the through holes (5) are laser cuts.

[0031] 7. The tape according to any of the preceding items, wherein the two lateral edges are ultrasonic or laser cuts.

[0032] 8. The tape according to any of the preceding items, which tape is free of through holes, and wherein the two lateral edges are ultrasonic or laser cuts.

[0033] 9. The tape according to any of the preceding items, which tape is open-ended and has two end edges which are separated from each other by the longitudinal length L in the longitudinal direction and are ultrasonic or laser cuts.

[0034] 10. A method of simultaneously producing N specimens of the tape according to any of the preceding items which are open-ended and have ultrasonic cut lateral edges, wherein N is an integer > 1, the method comprising the steps of:

[0035] i) providing a layered sheet material of substantially rectangular shape having a layered structure according to any of the preceding [1] to [4], a longitudinal length of L or more, and a transverse width W0 of N x W or more;

[0036] ii) passing the layered sheet material through an ultrasonic cutter having at least one horn and N+1 blades, wherein adjacent blades are separated from each other by a distance of W, such that each of the blades cuts into the sheet material to simultaneously cut the sheet material into the N tape specimens; and

[0037] iii) optionally forming one or more through holes (5) in each of the N tape specimens by laser cutting.

[0038] 11. The method according to

[10] above, wherein the ultrasonic cutter has M horn heads, each ith horn head driving K i blades, wherein M and each K i is an integer > 1, and wherein .

[0039] 12. The method according to

[10] or

[11] above, wherein the blades are circular disc blades (10) having a circular outer peripheral cutting face (10a) and the circular disc blades (10) roll over the layered sheet during ultrasonic cutting with the sample.

[0040] 13. The method according to any one of [9] to

[12] above, wherein the layered sheet is passed through the ultrasonic cutter at a forward speed in the range of 2 m / min to 10 m / min, preferably 3 m / min to 8 m / min, in each horn using ultrasonic waves having a frequency of 30 kHz and a power of 250 W to 350 W per blade attached to the horn.

[0041] 14. A ring spinning machine having two, four or eight spindles comprising a band according to [5] above as a spindle band. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A schematic representation of the spindle band of the present invention is shown.

[0043] Figure 2 Two photographs of the ultrasonic cut lateral edges of two different spindle band samples constructed as shown in Figure 1 are shown at 100 times magnification; the first sample on the left and the second sample on the right.

[0044] Figure 3 Two photographs of the transversal cross sections of the same two spindle band samples of Figure 2 are shown at 150 times magnification; the first sample on the left and the second sample on the right.

[0045] Figure 4 A photograph of a conventional cut spindle band (top) and the spindle band of the present invention (bottom) as shown in Figure 1 after two months of use in a ring spinning machine is shown.

[0046] Figure 5 A photograph of the laser cut lateral edges of the spindle band of the present invention constructed as shown in Figure 1 is shown.

[0047] Figure 6 A photograph of the laser cut lateral edges of the spindle band of the present invention constructed as shown in Figure 5Figure showing a photograph of a transversal section of the same specimen of the ribbon shown in the middle.

[0048] Figure 7 Figure showing a cross-section of a preferred ultrasonic cutting blade.

[0049] Figure 8 Figure showing a preferred ultrasonic cutting blade in the form of a disc when used for ultrasonic cutting. DETAILED DESCRIPTION

[0050] The belt or tape (“belt” or “tape”) of the present invention has at least one ultrasonic or laser cut edge. “Edge”, as used herein without further specification, for the purposes of the present invention, means one or more of the following:

[0051] a) a lateral edge of the belt or tape, which extends substantially or even completely parallel to the direction of travel of the belt or tape; preferably, it means both lateral edges of the belt or tape;

[0052] b) a terminal edge, i.e. one of the two belt or tape edges spaced apart from each other in the longitudinal direction L, which will make the belt or tape ring-like after joining the belt or tape together, for example by heat and pressure and optionally the joint use of a hot-melt adhesive; these terminal edges are preferably straight or in the form of a zigzag (so-called “finger-end” edges) (see also below);

[0053] c) an edge of a through-hole cut through the entire thickness of the belt;

[0054] d) a combination of two or more of a), b) and c) above.

[0055] Alternatively, in the case of necessity or appropriateness, individual edge types will be specified hereinafter in a) - c) above.

[0056] Feature ii) of item [1] of the summary means that there must be at least a lateral edge (1a, 1b) which is an ultrasonic or laser cut, or if the lateral edge is neither an ultrasonic nor a laser cut, there must be one or more through-holes (5) with a hole edge (5a) which is a laser cut.

[0057] Any ultrasonic or laser cut edge has the following structural effects observable on the edge thus formed:

[0058] a) the material of the first textile layer and / or the material of the first coating layer appears to solidify again after having softened or even melted at least partially to such an extent that either of these layers comprises or consists of a thermoplastic or a thermoplastic elastomer. Any fiber end of the first textile layer which would normally protrude as a sharp tip out of the cut edge in case the cutting has been done by a knife or punch, appears to be blunted by softening or melting and solidifies again when cut by ultrasound or laser, and / or is at least partially embedded into the thermoplastic / thermoplastic elastomer material from the first textile layer and / or the first coating layer.

[0059] b) the porosity or loft of the first textile layer itself is reduced with respect to the porosity or loft of the textile as visible in a longitudinal section.

[0060] Furthermore, the ultrasound and laser cut edges differ from each other in that the latter can exhibit traces of a yellowish or dark or possibly near black deposit which originates from the charring or even carbonization of organic material at the edge which has been newly formed due to the heating by the laser.

[0061] Furthermore, the surface roughness of the ultrasound and laser cut edges differs from each other or from the surface roughness of a conventional knife cut edge, in particular when the surface roughness is measured along the first textile layer.

[0062] In case of longitudinal or end edges, the edge roughness is measured for the purpose of the present invention along either of the contained layers, in particular along the first textile layer, as a height profile z(x) using a varying focal length, which is a well-known optical height profile measurement technique. The edge to be analyzed is considered to extend along the x (horizontal) and y (vertical) directions, and the profile height is considered to extend along the z direction. If the edge to be analyzed is a lateral edge, the x direction coincides with the longitudinal tape direction, the y direction coincides with the tape thickness direction, and the z direction coincides with the lateral tape direction. At a given constant distance between the lens and the tape specimen and at a given focal length, the surface portion of the edge is digitally gray-scale photographed. Then, at the same distance between the lens and the tape specimen but at a different focal length, the same surface portion of the edge is again digitally gray-scale photographed, each focal length being shifted by a fine focus shifting mechanism, for example by a piezoelectric element, until at the given focal length a photograph is obtained in which the center of the surface is in best focus. The center of the surface portion is one measurement point x i of the edge. The criterion of best focus of the center at position x i may be given, for example, if the Laplace filter L is as follows:

[0063] (1)

[0064] wherein in formula (1)

[0065] I(m,n) is the grey level intensity of the image pixel representing the center of the surface, the distance from this center (hence the height in the z direction) should be measured;

[0066] I(m,n+1), I(m+1,n), I(m,n-1) and I(m-1,n) are respectively the grey level intensities of the image pixels adjacent to the center pixel and above the center pixel (shifted by +1 in the y direction), to the right of the center pixel (shifted by +1 in the x direction), below the center pixel (shifted by -1 in the y direction), and to the left of the center pixel (shifted by -1 in the x direction); and

[0067] "~ 0" means that L should be minimal, or as close to zero as possible.

[0068] In formula (1), the values I(m,n), I(m,n+1), I(m+1,n), I(m,n-1) and I(m-1,n) can preferably each be replaced by the respective 2x2 or 3x3 neighborhood arithmetic mean, to reduce the noise sensitivity of the Laplace filter.

[0069] The previous best focus criterion, once satisfied as the center of the surface portion of given measurement point xi, is converted into the absolute distance z i between the camera and the center of the surface portion corresponding to xi, using for example the Gaussian lens law.

[0070]

[0071] where

[0072] o is the unknown distance between the center plane of the lens of the camera and the center of the surface;

[0073] d is the known distance between the center plane of the lens of the camera and the CCD of the digital camera, and this known distance is variable by the focusing mechanism, and is chosen so that the best focus criterion of the center of the surface portion is obtained; and

[0074] f is the known focal length of the lens of the camera (constant specific to the lens);

[0075] the Gaussian lens law is solved for the unknown o; and

[0076] z i corresponding to x i may for example be directly equal to o, or can be the sum of o plus a constant, an arbitrarily chosen scaling offset.

[0077] The above photographing process and distance estimation are repeated for other measurement points along the edge (i.e. other surface portions of the edge), each next measurement point xi+1 along the x direction with respect to the previous measuring point x i offset by some further typical constant offset until the height profile z(x) is completed.

[0078] For this determination of the height profile by means of focal length variation, even commercial devices exist.

[0079] This technique allows to measure the height profile along the edge of an individual layer within the belt or band sample of the invention, such as along the edge of the first fabric layer. In order to measure such a height profile z(x) along the edge of a layer, the belt or band sample is clamped between two rigid cubic cuboid blocks with planar surfaces so that the lateral or end edge to be measured is flush with one of the side edges of each of the two cuboid blocks. In this clamped-in state, the belt or band sample with the lateral or end edge to be measured facing upwards can typically be advanced along the measuring (x-) direction using a motor-driven advancing support. The result of the measurement is a one-dimensional lateral height profile z(x) of the edge as a function of the variable position x along the layer in question. Reference is made, for example, to the article "An optical method for measuring surface roughness of machines carbonfibre reinforced plastic composites" (Journal of Composite Materials 0(0), pages 1-14 (2016)). The measurement of the height profile z(x) will typically be carried out at a vertical height y which is half the thickness of the layer whose roughness is to be measured.

[0080] The surface roughness along the longitudinal or end edge of the layer under examination (as obtained from the above focal length variation) is then characterized using the well-known standard deviation (s), skewness (Rsk), kurtosis (Rku) parameters using the height profile z(x):

[0081] (2a)

[0082] (2b)

[0083] (2c)

[0084] wherein

[0085] x i is the displacement of the i-th measuring point in the advancing (x-) direction along the edge with respect to the starting point of the advancing movement;

[0086] z i is the height profile z(x) at the displacement x ithe height measured at the i-th measurement point of the set, as explained above, is measured by the change in focal length;

[0087] N is the corresponding height z of the measured edge i (x i ) the number of measurement points;

[0088] summing over all N measurement points;

[0089] where all symbols are defined as in equations (2a), (2b) and (2c); and

[0090] summing over all measurement points.

[0091] The surface roughness of the lateral or terminal edge of a tool cut, a laser cut and an ultrasonic cut differs from each other when measured as a height profile z(x) and characterized using the Rskand Rku, especially when measured along the first fabric layer. The absolute values of Rskand Rkuof the lateral or terminal edge of a tool cut, an ultrasonic cut or a laser cut depend on the belt construction and the cutting process characteristics and cannot be expressed in absolute values or absolute value ranges for the belts or belts of the present invention in advance. However, this is not essential for the purposes of the present invention.

[0092] It is expected that Rskaccording to the above equation (2b) is most positive, i.e. the positive value is the largest, for a laser cut edge, that Rskaccording to the above equation (2b) is less positive, i.e. the positive value is smaller, for an ultrasonic cut edge, and that Rskaccording to the above equation (2b) can become least positive, i.e. the positive value is the smallest or even closest to zero, for a tool cut edge. This is because the temperature gradient from the outside of the belt (at the edge to be cut) to the inside (the body) is the highest in laser cutting, the lowest in ultrasonic cutting, and becomes almost non-existent in tool cutting. Thus, by tool cutting a sample of the belt or belt of the present invention, such that the new tool cut reference edge extends parallel to the original lateral or terminal edge of the belt or belt sample, and measuring / analyzing both the original lateral or terminal edge of the belt or belt and the newly formed tool cut reference edge, and comparing their Rskvalues according to the above equation (2b), it can be first determined whether the original lateral or terminal edge of the belt or belt sample is a tool cut on the one hand or a laser or ultrasonic cut on the other hand. In the former case, there should be no statistically significant difference between the Rskvalue of the original lateral or terminal edge and the Rskvalue of any of the newly tool cut reference edges. In the latter case, the original lateral or terminal edge should have a significantly more positive, i.e. a significantly larger positive value, Rskvalue than the Rskvalue of one of the newly tool cut reference edges.

[0093] The standard deviation *s* of the lateral or distal edge of a laser-cut incision according to formula (2a) above is expected to be less than that of the lateral or distal edge of an ultrasonic or blade-cut incision according to formula (2a) above. The expected Rku of the lateral or distal edge of a laser-cut incision according to formula (2c) above is greater than that of the lateral or distal edge of an ultrasonic or blade-cut incision. This is because lasers provide the sharpest cut of all three techniques (and therefore the smoothest edge). Therefore, by ultrasonically cutting one or more reference cuts of the belt or belt specimen under ultrasonic cutting conditions (which provide a cut that visually closely approximates the original lateral or end edge of the belt or belt specimen, and such that the newly cut reference edge extends parallel to the original lateral or end edge of the belt or belt specimen), and by measuring / analyzing both the original lateral or end edge of the belt or belt and the newly formed cut reference edge, and comparing their s values ​​according to formula (2a) above or their Rku values ​​according to formula (2c) above, it can be further determined whether the original lateral or end edge of the belt or belt specimen is a laser cut on one hand or an ultrasonic or tool cut on the other. In the former case, the s value of the original lateral or end edge should be less than the s value of one of the newly ultrasonic cut reference edges; and the Rku value of the original lateral or end edge should be greater than the Rku value of one of the newly ultrasonic cut reference edges. In the latter case, the s or Rsk value of the original lateral or distal edge should not be statistically significantly different from or significantly greater than the s or Rsk value of one of the recent ultrasonic incision reference edges, respectively.

[0094] If the belt or strap of the present invention comprises a woven first fabric layer, the aforementioned reference edge used for determining the lateral edge is preferably offset from the lateral edge in the z-direction, and this offset is the spatial frequency of the woven fabric in the z-direction. an integer multiple of the reciprocal of n, i.e., n / Where n is an integer ≥ 1. Otherwise, comparing the surface roughness of the lateral edge and the reference edge would be meaningless. At an offset n / from the corresponding lateral band edge The location of this additional reference incision is in Figure 1 The bottom part is shown as a dashed line.

[0095] For each end edge of the serrated form, the so-called "finger tip" edge (see also below), the corresponding additional reference cut edge is made only as its straight extension into the belt or band. Such additional cuts for the extensions of the two serrated edges are... Figure 1 The bottom part is again shown with a dashed diagonal line.

[0096] Any such reference cutter kerf edge can be made, for example, using a trimmer (for example, an IDEAL trimmer offered by Krug & Priester, Germany).

[0097] It is to be understood that any such further reference kerf should avoid any through holes that can be present in the belt, also as Figure 1 shown by the dashed reference kerf line in the bottom portion of Fig. 2.

[0098] In the case of a hole edge, the edge roughness cannot be determined directly by the previous method. However, if the hole edge in question shows signs of melted and resolidified material, it has to be assumed that it is a laser kerf. In the applicant's experience, no other technology is used to cut such a hole with a melted edge into a belt; in particular, ultrasonic cutting is not possible because it forces a kerf with only very low curvature, or it can even only produce a straight kerf.

[0099] The belt or the band of the present invention comprises as mandatory components a first fabric layer (which will typically form the traction layer of the belt or the band) and a first coating layer, wherein the first fabric layer comprises a thermoplastic, or the first coating layer comprises a thermoplastic or a thermoplastic elastomer; or the first fabric layer comprises a thermoplastic, while the first coating layer comprises a thermoplastic or a thermoplastic elastomer.

[0100] In an alternative, the first fabric layer can be any fiber-containing layer of sheet-like construction. Such a sheet-like layer essentially has the shape of a cuboid with a geometrical length, a geometrical width and a geometrical thickness, wherein the geometrical length and the geometrical width are each much larger than the geometrical thickness. The textile can be a woven fabric (such as a plain woven or a twill woven fabric), a knitted fabric, a non-woven fabric (such as a felt or a fleece).

[0101] In a second alternative, the first fabric layer can comprise or consist of an array of non-interlaced reinforcing cords extending parallel to each other.

[0102] Preferably, the first fabric layer is a woven fabric or an array of non-interlaced reinforcing cords.

[0103] The first fabric layer preferably forms or is comprised in the traction layer of the belt. To make the best use of the advantages of the tensile properties of the textile, it seems preferable to cut the lateral edges of the belt in such a way that, if in the form of a woven fabric, the warp filaments (i.e. the pick filaments) of the woven fabric extend parallel to said lateral edges and the weft filaments (i.e. the fill filaments) of the woven fabric extend transversely to said lateral edges.

[0104] The first fabric layer can be wholly thermoplastic fibres or filaments, or it can comprise thermoplastic fibres or filaments mixed with natural fibres or filaments. Preferred thermoplastics are thermoplastic polyolefins; polyesters, in particular aromatic polyesters such as PET; aliphatic polyamides, such as in particular nylons; or aromatic polyamides such as polyaramids. The natural fibres or filaments are preferably selected from the group consisting of flax, jute, hemp, wool, cotton and ramie, most preferably the natural fibres are cotton. If the first fabric layer comprises a combination of thermoplastic fibres or filaments and natural fibres or filaments, the weight ratio of thermoplastic fibres or filaments to natural fibres or filaments is preferably in the range 2:8 to 9:1.

[0105] The first coating layer comprises or, preferably, consists of a thermoplastic or a thermoplastic elastomer. Preferred thermoplastics for the first coating layer are thermoplastic polyolefins such as polyethylene or polypropylene, substantially atactic ethylene / C 3-12 - alpha-olefin copolymers (examples of alpha-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 chloroethylene (PVC) or copolymers of chloroethylene with partial dichloroethylene are technically feasible, but are less preferred in view of the toxic fumes that can be generated during laser or ultrasonic cutting. Preferred examples of thermoplastic elastomers for the cover layer are thermoplastic elastomer block copolymers (such as styrene block copolymers, in particular styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene / butylene-styrene and styrene-ethylene / propylene-styrene block copolymers), copolymers of hard blocks of medium density polyethylene and soft blocks of ethylene / alpha-olefin copolymers, thermoplastic polyurethanes (such as copolymers of polyester glycols or dihydroxy polyethers with diisocyanates), polyether- / ester block amides and thermoplastic elastomer ionomers.

[0106] A more preferred example of the material for the first coating layer is a thermoplastic elastomer, in particular a TPU. Suitable such TPU's are generally obtainable by reacting a diisocyanate containing hard block segment with a polyester diol soft block segment. The diisocyanate containing hard block can be obtained by reaction of a diisocyanate with a diol chain extender. The diisocyanate can be a pure compound or a mixture of diisocyanates. In a 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 and 3-methylpentane-1,5-diol, or diol ethers such as diethylene glycol, dipropylene glycol and tripropylene glycol, and amino alcohols such as ethanolamine, N-methyldiethanolamine and the like. The polyester diol soft segment used preferably has a molecular weight of 500 to 20,000. They can be prepared by reaction of a diol with a dicarboxylic acid, or more conveniently, by reaction (transesterification) of a diol with a dimethyl ester of a dicarboxylic acid and boiling off the low boiling methanol. The diol used for the polyester diol is an aliphatic straight chain or branched C2-C8diol which optionally can contain a carbocyclic saturated C5-C6ring. Examples thereof 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 of the polyester diol is an aliphatic straight chain or branched C2-C8dicarboxylic acid. Examples thereof are oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid or dimethyl esters thereof, sebacic acid, phthalic anhydride, tetrachlorophthalic anhydride or dimethyl terephthalate or mixtures thereof. The TPU is produced by reaction of the diisocyanate containing hard block with the polyester diol soft segment using the respective free and reactive end groups. The most preferred TPU is Lubrizol of the type Estane®. More preferred is 58277, 54600 and 54610; most preferred is 58277. The TPU is preferably not blended or alloyed with other types of polymers.

[0107] The thermoplastic or thermoplastic elastomer, in particular the TPU, suitable for the first coating layer preferably has a Shore A hardness in the range of 60 to 100, more preferably 70 to 95 at room temperature.

[0108] Preferably, the first coating layer comprises at least 80 wt.-%, more preferably at least 90 wt.-%, still more preferably at least 95 wt.-%, and most preferably 100 wt.-% of a thermoplastic material or a thermoplastic elastomeric material, as exemplified below. These amounts are indicated based on the total weight of the first coating layer.

[0109] The thermoplastic in the first fabric layer and the thermoplastic or thermoplastic elastomer in the first coating layer can be incompatible with each other. By "incompatible" is understood that a blend of the thermoplastic from the first fabric layer and the thermoplastic or thermoplastic elastomer from the first coating layer exhibits two discrete glass transition temperatures in differential scanning calorimetry (DSC). Even in this case of incompatibility, the ultrasonic or laser cutting will fuse these two layers together at the formed edge. A particular example of such an incompatible pair of materials is a polyester (in particular PET or PBT) of the first fabric layer and a thermoplastic polyurethane (TPU, in particular a TPU as exemplified above) of the first coating layer. Such a textile and such a coating layer can be fused together at the lateral edges with ultrasonic or laser cutting even without a processing aid such as a homopolymer of acrylate and a copolymer of acrylate with styrene, olefin and / or acrylonitrile.

[0110] Preferably, the first fabric layer and the first coating layer are immediately adjacent to each other or are separated from each other only by an adhesive layer, which can comprise a hot-melt adhesive or a cross-linked adhesive such as a cross-linked polyurethane.

[0111] However, the orientation of the belt or band during its final application is not important. That is, the first fabric layer can face the driving pulley, or it can form a conveying surface for the articles to be conveyed (if the band is used as a conveyor belt), or it can constitute a driving surface of an axle or pulley (for example, if the band is used for power transmission).

[0112] The belt or band of the present invention can optionally comprise a further fabric layer and or one or more top coating layers. The configuration of this further fabric layer can be similar as described above for the first fabric layer. The optional top coating layer can be applied with abrasion resistance, chemical resistance, antibacterial properties, moisture resistance and / or with antistatic properties. Such top coating layers are conventional per se.

[0113] The top coating layer can also be provided with an embossed profile to vary its coefficient of friction. In a preferred embodiment, there is a top coating layer having two longitudinally extending portions having a similar, preferably equal, transversal width, which are adjacent to each other in the transversal direction, and wherein these two portions exhibit different static coefficients of friction (COF) with respect to steel or paperboard.

[0114] Furthermore, the belt of the present invention can optionally comprise one or more through-holes perforated in the belt along its thickness direction. In this case, the preferred application of such a belt is as a vacuum suction belt, which allows the adhering of conveyed articles to the conveying surface of the belt by vacuum suction. In this case, the belt will preferably have a plurality of such through-holes, more preferably arranged in a specific pattern, such as a square or rectangular pattern, wherein the distance between adjacent through-holes is not greater than, preferably significantly less than, the size of the conveyed articles, to ensure vacuum suction to each such article placed on the belt. An exemplary rectangular pattern of a plurality of such through-holes 5 is shown in the bottom portion of Figure 1 . These through-holes preferably have a circular cross-section, as shown in the lower portion of Figure 1 , in which case their diameter is preferably in the range of 1 mm to 3 mm. According to the applicant's experience, laser cutting is the only feasible technology to produce such through-holes with partially melted and sealed hole edges.

[0115] The overall geometric thickness T of the belt or the belt is typically chosen such that it corresponds to the overall geometric thickness of one of the respective prior art belt or belt types mentioned in the background section. "Geometric thickness" is herein understood as the thickness measured with a thickness gauge using a defined overpressure of 0.2 bar (overpressure means a pressure higher than ambient pressure, which is typically about 1 bar). Preferably, the overall geometric thickness T of the belt or the belt is in the range of 0.5 mm to 15 mm, more preferably in the range of 0.5 mm to 5 mm, more preferably in the range of 0.5 mm to 2.5 mm.

[0116] The belt or the belt of the present invention preferably comprises an amount of entrapped gas. This can be located in the first fabric layer and / or in any of the optional further fabric layers of the belt or the belt, that is, these fabric layers are not fully impregnated or not impregnated at all. Alternatively or additionally, the first coating layer can be in the form of open-cell bubbles. Such gas entrapment is advantageous during ultrasonic or laser cutting, because during ultrasonic or laser cutting the gas can be expelled to the environment, thus compensating any volume expansion (bulging) of the belt or the belt near the lateral edges, i.e. the ultrasonic or laser cut. In this preferred embodiment, the gas content G [in vol%] of the belt or the belt is preferably in the range of 5% to 20%, wherein G is calculated according to the following formula:

[0117]

[0118] wherein

[0119] V GeoBis the geometric volume of the cuboid belt or belt sample to be tested; obtained on the cuboid belt or belt sample by geometric length and width measurements, and by geometric thickness measurement with a thickness gauge at 0.2 bar overpressure (as outlined above);

[0120] V R is the volume of the reference sample with a defined known volume;

[0121] is the initial pressure rise over time (dP1 / dt at t=0) measured in a completely evacuated vacuum chamber filled with helium using a helium permeation leak standard;

[0122] is the initial pressure rise over time (dP2 / dt at t=0) measured in the vacuum chamber when the vacuum chamber (containing the reference sample and being completely evacuated) is filled with helium using the helium permeation leak standard;

[0123] is the initial pressure rise over time (dP3 / dt at t=0) measured in the vacuum chamber when the vacuum chamber (containing the cuboid belt sample and being completely evacuated) is filled with helium using the helium permeation leak standard; and

[0124] , and are measured in the vacuum chamber at room temperature using a rotary vacuum gauge.

[0125] The determination of the volume percentage of the pressure difference rise above is known per se. See for example the publication "Volume Determination of a Vacuum Vessel by Pressure Rise Method" by Setina J. and Erjavec B. published at the 19th IMEKO World Congress "Fundamentals and Applied Metrology", Lisbon, September 6-11, 2009; and the literature cited therein. The initial pressure rise over time can also be taken from a non-infinitesimal time period, i.e. ΔP / Δt, instead of dP / dt, since the pressure rise is initially linear.

[0126] In a further preferred embodiment, which can stand alone or in combination with the above described preferred embodiments of gas entrainment, the textile is a woven fabric having warp and weft threads, wherein the warp threads extend substantially but not exactly along the longitudinal direction of the belt. That is, during cutting of the lateral edges of the belt or band by any technique (conventional or according to the present application), it cannot be guaranteed that the lateral cut edges will exactly parallel to said warp or end threads. Thus, it also cannot be guaranteed that the end threads exactly extend along the longitudinal direction of the belt or band. If the lateral edges are knife cuts (of the prior art) and the end threads do not exactly extend parallel to the lateral edges, the lateral edges can have an increased tendency to wear, because the end threads at the lateral edges can have been damaged or even cut open, thereby forming open ends. This problem is even more severe if the end threads are in the form of multifilaments consisting of a plurality of fine fibers (as is customary in order to improve the bendability of the belt or band over small radius pulleys). The band with the woven fabric and lateral edges cut by ultrasound or laser shows no wear even if the end threads of the fabric, in particular the multifilaments, are slightly inclined with respect to the longitudinal direction of the band, such as by an angle of 0.1° to 1°, or by an angle of 0.1° to 0.5°. The term "inclination" can herein refer to the average direction of the end threads (averaged over the entire length of the band) to be inclined by the specified angle. Alternatively, it can refer to the local direction of the end threads (for example in a longitudinal section of the belt or band of 2 cm to 5 cm) can have such an angle with respect to the longitudinal belt or band direction.

[0127] The belt or band according to the present application can be in an end-open form, comprising two end edges 6, 7 as shown in the bottom part of Figure 1 which are to be joined together to form the respective endless form (see below). In this end-open form, it has a longitudinal length L, while in the respective endless form, it has a circumference L. If the two end edges are straight, the band has the shape of an elongated strip when viewed in a top view, preferably in the shape of a very elongated rectangle or parallelogram. However, for end joining purposes, the two end edges are preferably shaped into a regular zigzag shape, each having the same teeth and the same recesses in an alternating form, such that upon end joining, each tooth of one end edge will fit closely into the respective recess of the other end edge, and vice versa. This end joining technique is commonly referred to as "finger end" joining technique and is preferred for the purposes of the present application. In the case of such zigzag end edges, the end-open band of the present application will look similar in a top view as shown in the bottom part of Figure 1 .

[0128] The belt or band (open-ended or endless) of the present invention has a width W which is generally constant and is a typical width for a band used in industrial applications. For power transmission belts and machine belts, the width W can preferably be in the range of 10 mm to 25 mm, more preferably in the range of 10 mm to 20 mm (which is a preferred application for the machine belts of the present invention, see below). The lateral edges are preferably straight, parallel to each other and separated from each other in the transverse (z-) direction by said constant width W.

[0129] The longitudinal length L of the open-ended belt or band of the present invention or the circumference L of the endless belt or band of the present invention is understood to be the quotient obtained by dividing the geometric surface area of the belt or band by said constant width W. The geometric surface of an open-ended or endless belt or band can generally be obtained by weighing the belt or band and comparing this weight with the weight of a planar test specimen of the same belt or band having a known geometric area (e.g. 0.01 m 2 In the preferred open-ended belt or band of the above-mentioned elongated rectangular or parallelogram shape with straight end edges, the longitudinal length L (where the result is the same within the range of experimental error) can also be obtained as the length of one of the lateral edges (rectangular) or as the average of the lengths of the two lateral edges (parallelogram). In the preferred open-ended belt or band of the above-mentioned elongated rectangular or parallelogram shape with sawtooth "finger" end edges, the longitudinal length L (where the result is the same within the range of experimental error) can also be obtained as the longitudinal distance from the half height of a tooth of one end edge 6 to the half height of a tooth of the other end edge 7, as shown in the lower part of Figure 1

[0130] In another preferred embodiment of the present invention, the belt or band is endless. In this endless form, it has an outer circumference L which substantially corresponds to the longitudinal length L of the open-ended belt or band made into it. This outer circumference L can extend along the "pitch line" or "neutral line" of the endless band (i.e. the line inside the endless band which is constant in length when the endless band is used). As is customary in the art, the term "outer circumference" shall herein refer to both the physical outer circumference lateral edges of the endless band and the associated length L of such outer circumference lateral edges. The end joining to make the belt or band endless is typically done as a last step and, as is also customary, a hot press and optionally a hot melt adhesive are used.

[0131] In the previous sense, the ratio of the width W to the longitudinal length L (or to the circumference L) is preferably in the range of 1 : 100 to 1 : 2'000, preferably in the range of 1 : 150 to 1 : 2'000, and more preferably in the range of 1 : 200 to 1 : 2'000.

[0132] ​Any belt and band of the invention is preferably in the form of a so-called "flat belt", i.e. a belt or band without transversely extending teeth and associated recesses on its top and bottom surfaces, and / or without longitudinally extending grooves and associated ridges on its top and bottom surfaces.

[0133] The belt or band of the invention can be used for any application for which a corresponding conventional conveyor belt, power transmission belt or machine belt would be used with the same layer construction but with knife cut edges. It is particularly suitable for any use in which during use particulate dust or fibre fluff can form and can contaminate the edges, if all edges contained therein are ultrasonic or laser cut. Such a belt or band of the invention withstands the accumulation of such dust or fluff at or in the edges due to its fusion sealing. In view of this advantageous property, such a belt or band of the invention can be used in such a dusty or fluff producing environment even if it is not equipped with anti-static means, such as a coating with embedded anti-static particles, or a fabric containing anti-static filaments. A further application of a belt or band of the invention for which all edges are ultrasonic or laser cut is an environment in which solvents, such as acetone, can contaminate the belt or band. It is observed that sealing the edges by partial melting prevents such solvents from penetrating into the belt or band. An example of such an application is in the paint or cosmetics industry or in a chemical plant in which such solvents are manufactured or packaged.

[0134] Yet another further application of a belt or band of the invention for which all edges are ultrasonic or laser cut is an environment in which mould or bacteria can contaminate the belt or band. It is observed that sealing the edges by partial melting prevents such micro-organisms from penetrating into the belt or band. An example of such an application is in the food industry.

[0135] However, a preferred application is the use of the machine belt of the invention as a spool belt. Spool belts are typically used in ring spinning machines of the type in which the spindles are driven by a ring-shaped belt loop which is formed by the spool belt. This is a use in which fluff is formed during operation. There are variants of ring spinning machines in which two, four or eight spindles are driven by one spool belt, and the spool belt of the invention is suitable for all of these spindles. It has proven that the spool belt of the invention does not accumulate abrasive fluff on its ultrasonic or laser cut edges at all, even after long periods of use (see example and associated drawing).

[0136] A schematic representation of a belt or band 1 of the invention is shown in Figure 1is shown in the upper part. It comprises a first fabric layer 2 and a first coating layer 3. The first fabric layer 2 consists of a woven fabric of mixed PET / cotton filaments (50:50). One of the lateral edges of the ultrasonic or laser cut is denoted by the number la. The first fabric layer 2 and the first coating layer 3 are adhered together by an adhesive layer 4 comprising cross-linked polyurethane. The belt or band further comprises optional through-holes (one through-hole is shown by reference numeral 5) which are perforated into it. Each such through-hole 5 is formed by a hole edge 5a which must be a laser cut. Figure 1 The lower part shows a top view of the belt or band of the invention with a plurality of through-holes (only one through-hole is denoted by the number 5).

[0137] The cutting of the edges of the belt or band of the invention by ultrasonic or laser will be described in detail hereinafter.

[0138] The ultrasonic cutting process is used for the lateral edges (from which one or more bands are cut out of a wider layered sheet material (master band)) or for cutting the end edges.

[0139] Generally, ultrasonic cutting is substantially adiabatic. That is, any heat introduced by the ultrasonic cutter at a given location of the edge being cut is at least retained while the ultrasonic cutting blade is located (substantially located) at that location, without being removed from that location by any explicit cooling means (such as an air or inert gas blast directly applied to that location or otherwise). Thus, the ultrasonic cutter, when used in the process of the invention, does not have, employ or require explicit cooling means (such as pipes, tubes, hoses, nozzles or fins) which can directly deliver a cooling medium (such as air or inert gas) to the cutting zone on the surface of the belt or band. It is understood, however, that in the case of ultrasonic cutting, the blade and / or horn and / or the welding head can be cooled by such cooling means.

[0140] The ultrasonic waves are preferably in the frequency range of 20 kHz to 100 kHz, more preferably 20 kHz to 40 kHz, most preferably about 30 kHz. This relates to the resonant frequency at which the horn of the one or more cutting blade combination normally works, and which is a constant specific to the combination of horn and cutting blade.

[0141] The vertical amplitude (i.e. in the direction of the cut) of the ultrasonic oscillations is preferably in the range of 10 pm to 100 pm, more preferably 15 pm to 60 pm.

[0142] However, the power of the ultrasonic waves and the advancing speed of the blade should be chosen such that a certain amount of energy (Joule / m 2) is applied so that the thickness of the cut edge is not significantly bulged relative to the main body thickness of the belt or band, but still has sufficient local heating so that the cut edge is sealed by melting the thermoplastic or thermoplastic elastomer material of the textile from the traction layer and / or other layers coated or laminated onto the traction layer. At a frequency of 30 kHz, for example, it is preferred to use a power of 200 to 400 watts per cutting blade, more preferably 250 to 350 watts. Lower frequencies can require higher power per cutting blade; for example, reducing the frequency from 40 kHz to 20 kHz (2-fold reduction to 1 / 2) can require more than 4 times the power per cutting blade.

[0143] To achieve sufficient edge sealing without bulging, for a given belt or band type, a given cutting direction (e.g., parallel to the warp threads of the first woven fabric, or parallel to the weft threads of the first woven fabric), a given resonant frequency of the horn / blade, and a given type and number of blades driven by the horn, there is an optimal forward speed v [in units of m / min] of the blade relative to the sheet that is roughly proportional to the nominal power P [in units of watts] of the ultrasonic cutter being employed:

[0144] (1)

[0145] For a given and fixed combination of sheet, horn / blade, and ultrasonic frequency, constant1 in (1) can be found by varying the forward speed v and observing the v that achieves both of the above objectives. The optimal value of v divided by the ultrasonic power P used gives the constant1 required in (1).

[0146] Figure 2 And Figure 3 shows the effect of varying the forward speed of the blade while keeping other process parameters constant. That is, Figure 2 the left photo in Figure 3 the left photo in Figure 1 show the ultrasonically cut side edge la and cross-section of a ribbon having the configuration shown in Figure 2 the left photo in Figure 3 the left photo in Figure 2 the right photo in Figure 3 show the ultrasonically cut side edge la and cross-section of a ribbon having the configuration shown inFigure 1 The ultrasonic cutting side 1a and cross section of the spindle belt shown in the figure are shown, but the advance speed v of the blade is obviously too low. Figure 2 The photo on the right shows an inadequate lateral edge seal: the white fabric and the black TPU from the first coating layer are not actually blurred and melted together. Figure 3 The photograph on the right side, shown on its right side, reveals no bulge whatsoever; instead, there is even a slight reduction in thickness near the edge of the lateral ultrasonic cut. Given this inadequate edge seal, this spindle sample may perform unsatisfactorily during use.

[0147] Preferably, the cutting blade's feed speed v is kept below a critical feed speed, at which the cutting resistance becomes too strong for the ultrasonic cutter to resonate, which can be detected in particular by a significant drop in the oscillation amplitude. Ultrasonic cutters that monitor the oscillation frequency and amplitude are available on the market, and which automatically increase the applied power in the event of resonant de-resonance. For the belt type illustrated above, a suitable optimal feed speed v will, in most cases or even typically, be in the range of 2 m / min to 10 m / min, preferably 3 m / min to 8 m / min, and more preferably 5 m / min to 7 m / min, at a power of 250 to 350 watts per blade.

[0148] Once constant1 of formula (1) is known, formula (1) allows for a rough prediction of the forward velocity v that must be selected for a given ultrasonic power for the same given and fixed combination of sheet, welding head / blade and ultrasonic frequency.

[0149] The cutting blade 8 preferably has Cs symmetry, wherein the mirror surface is parallel to the forward movement direction of the blade relative to the belt or band to be cut and parallel to the ultrasonic oscillation direction. In this way, equal power is ensured to flow to either side of the blade, thereby producing two identical ultrasonic slit sides. The cutting surfaces 8a and 8b of the blade 8 are preferably planar and preferably at an angle of 60° to 100°, preferably 70° to 80°, relative to each other, such as... Figure 7 As shown in the figure. More preferably, the blade is in the form of a disc 10, which has an outer circular cutting surface (e.g., Figure 8 (As shown). One of the circular outer circumferential cutting surfaces is indicated by the number 10a. Such a disc-shaped blade 10 can be rotatably mounted on the welding head 9 on the axle 11. During ultrasonic cutting at a forward speed V, such a disc-shaped blade 10 also rolls on the belt material 12 to cut one or more belts or strips. The same preferred features regarding the cutting surfaces and their corresponding angles as explained above for the blade also apply to such a rotatable disc-shaped blade 10.

[0150] In a preferred process embodiment, a plurality of blades are used to simultaneously cut a number of belt or tape samples from a sheet material (master tape). In this embodiment, the sheet material preferably has a width W0 of 400 mm to 500 mm; and is cut by an ultrasonic cutter having preferably 3 to 4 horn(s) (each horn preferably driving 10 to 12 blades), the ultrasonic frequency preferably being about 30 kHz, the power of each horn preferably being in the range of 300 to 400 Watts, and the advance speed preferably being in the range of 3 to 5 m / min, it being understood that this respects the previous considerations regarding the advance speed.

[0151] The horn 9 is preferably side-cutting, i.e. the horn preferably cuts by a sawing action rather than by a punching action. For this preferred cutting mode, the horn preferably has at least one variant, i.e. a straight side cutting edge that narrows towards the blade tip, such as preferably at an angle in the range of 5 to 45 degrees with respect to the direction of the ultrasonic vibrations. In an alternative preferred embodiment of the side-cutting / sawing action, the blade can have a downward cutting edge and have a shape of a substantially circular or elliptical arc.

[0152] The direction of the ultrasonic vibrations and thus the oscillation direction of the blade during cutting, when viewed along the cutting direction, is preferably perpendicular to the surface of the sheet material to be cut into a plurality of belts; but when viewed in a direction transverse to the cutting direction, it is then slightly inclined with respect to the surface normal of the belt. The angle of inclination with respect to the surface normal of the sheet material is preferably from 5° to 40°, more preferably from 20° to 40°, most preferably about 30°.

[0153] The ultrasonic cutting equipment comprising the horn and the blade is itself conventional. Preferably, it is equipment commonly used in the field of food slicing or garment cutting.

[0154] The laser cutting process can be used for any edge of the belt or tape. In the laser cutting process, the heat introduced by the laser cutter is preferably removed from the cutting zone by a cooling medium (such as air or an inert gas) that is directly blown onto the cutting zone. Thus, the laser cutter used in the process of the present invention preferably has and employs a shown cooling device (such as a pipe, tube, hose, nozzle or fin) that directly conveys a cooling medium (such as air or an inert gas) to the cutting zone on the surface of the belt or tape.

[0155] In order to achieve both sufficient edge sealing and no bulging with laser cutting, for a given belt or tape type, a given cutting direction (e.g. parallel to the warp threads of the first woven fabric, or parallel to the weft threads of the first woven fabric), a given belt or tape thickness d [in m], and a given laser type, the optimal advance speed v [in m / min] of the laser with respect to the sheet material is roughly proportional to the intensity of the laser beam employed:

[0156] (2)

[0157] For a given belt or belt type, by changing the forward speed v under a fixed laser intensity and a fixed cutting direction and observing the v that achieves the two aforementioned goals, constant2 in (2) can be found. This is also a single parameter variation within the capabilities of those skilled in the art. Dividing this optimal value by the laser intensity used yields the constant required in (2), i.e., constant2.

[0158] Similarly, once constant2 of formula (2) is known, formula (2) allows for a rough prediction of the forward speed v that must be chosen for a given laser intensity for the same belt or belt type and cutting direction.

[0159] The laser used is preferably a CO2 (infrared) laser. More preferably, it is a "slab" CO2 laser, and even more preferably, in which two mirrors are shaped to provide unstable behavior in the unrestricted dimensions of the resonator. The resonator of the slab laser is preferably composed of ceramic, for example, selected from the group consisting of Al2O3, BeO, and AlN. The excitation electrode is then located outside the ceramic resonator, which allows for better cooling of the electrode. It has been found that replacing the metal (aluminum) resonator with a ceramic resonator improves the shape of the edge (and therefore the notch).

[0160] The preferred power range for lasers is 100 watts to 200 watts.

[0161] Figure 5 and Figure 6 Show them respectively as follows Figure 1 The upper portion shows photographs of the laser-cut lateral edges and transverse sections of a sample of the ingot strip of the present invention, constructed as shown. Figure 5 It is clearly visible that the white fabric and black TPU are almost completely blurred due to the melting of the edge material. On the other hand, Figure 6 This shows that no bulges occurred near the lateral edges of the band.

[0162] The invention will now be illustrated by the following non-limiting examples.

[0163] Example

[0164] Example 1: Multiple spindles can be manufactured simultaneously by ultrasonically cutting the lateral edges of the spindle from the main belt.

[0165] The main belt has a width of 500mm, a thickness of 0.7mm, and a weight of 0.7kg / m. 2 The weight per unit area, having a layered structure similar to that found in the applicant's commercial spindle strip D-8, was used as the starting layered sheet.

[0166] This master tape was mounted on the feed roll of a commercial multi-blade ultrasonic cutter (Fabotex TCU 400 with 4 welding heads and a total of 40 blades, operating at 30 kHz and with a total power of 1500 Watt). The blades were separated from each other by 12.7 mm. The master tape was passed through the ultrasonic cutter with a forward speed of 3 m / min. 39 specimens of the spool tape of the present invention (each having a width of 12.7 mm) were simultaneously obtained, wherein the selvage of a few millimeters from each border of the master tape was discarded.

[0167] Example 2: Field test of conventional spool tape (lateral edge knife cut) versus spool tape of the present invention (lateral edge ultrasonic cut)

[0168] A ring spinning machine with four spool drives was equipped with either a spool tape specimen prepared according to the procedure of example 1 or a specimen of a reference spool of the same construction, except that the lateral edges were only knife cuts and no further measures were taken to prevent lint contamination of the lateral edges. The ring spinning machine of each case was operated for two months, wherein the spools were operated at at least 18Ό00 rpm. After 2 months of service time, the spool tapes were inspected for lint contamination. Figure 4 Photos showing both types of spool tapes are shown. The top photo shows the state of the reference spool tape. The edges have a large amount of white lint sticking vertically from the edges. In contrast, the spool tape of the present invention is completely free of lint at the edges (bottom photo according to example 1). Figure 4 ​

Claims

1. A belt, said belt being open ended and having two end edges (6, 7) and having a longitudinal length L in a longitudinal direction, said belt being adapted for a conveyor belt (1) or a power transmission belt (1), said belt comprising: a) two parallel lateral edges (la, lb) each extending in said longitudinal direction and being separated from each other by a transverse width W; b) a first fabric layer (2); and c) a first coating layer (3); characterized in that i) the first fabric layer (2) comprises fibers of thermoplastic and the first coating layer (3) comprises thermoplastic; and ii) the lateral edges (la, lb) are ultrasonic or laser cuts.

2. The belt of claim 1, wherein, said belt comprises d) one or more through holes (5) through the total thickness T of the belt, each of said through holes (5) being formed by a hole edge (5a).

3. The belt of claim 1, wherein, said belt is adapted for a cord belt.

4. The belt of claim 1, wherein, said first fabric layer (2) comprises filaments of thermoplastic.

5. The belt of claim 1, wherein, said first coating layer (3) comprises thermoplastic elastomer.

6. The belt of claim 1, wherein, the first fabric layer (2) comprises natural fibers.

7. The belt of claim 6, wherein, said first fabric layer (2) comprises natural filaments.

8. The belt of claim 1, wherein, the first fabric layer (2) comprises fibers of polyester.

9. The belt of claim 8, wherein, said first fabric layer (2) comprises filaments of polyester.

10. The belt according to claim 8 or 9, wherein said polyester is PET.

11. The tape of any one of claims 1-9, wherein, the first coating layer (3) consists of TPU.

12. The tape of any one of claims 1-9, wherein, said transverse width W is in the range of 10 mm to 25 mm.

13. The belt of claim 12, wherein, said transverse width W is in the range of 10 mm to 20 mm.

14. The belt according to any one of claims 1-9, comprising one or more of said through holes (5) and the hole edges (5a) of the through holes (5) are laser cuts.

15. The tape of any one of claims 1-9, wherein, said two lateral edges (la, lb) are ultrasonic cuts.

16. The belt according to any one of claims 1-9, said belt being free of through holes and wherein said two lateral edges (la, lb) are ultrasonic cuts.

17. The tape of any one of claims 1-9, wherein, the two end edges (6, 7) being separated from each other by the longitudinal length L in said longitudinal direction are laser cuts.

18. The tape of any one of claims 1-9, wherein, the ratio of the transverse width W to the longitudinal length L is in the range of 1:100 to 1:2000.

19. An endless conveyor belt (1) obtained by making the belt according to any one of claims 1 to 18 into a loop by joining the ends of the belt adapted to convey; wherein, a ring-like form is obtained by joining the two end edges (6, 7).

20. An endless power transmission belt (1) obtained by making endless the belt according to any one of claims 1-13 or 15-17 adapted for a power transmission belt; wherein, a ring-like form is obtained by joining the two end edges (6, 7).

21. A ring-shaped spool tape obtained by making a ring of the tape according to any one of claims 1-13 or 15-17 adapted for a spool tape; wherein, a ring-like form is obtained by joining the two end edges (6, 7).

22. A method of simultaneously producing N trials of a belt according to any one of claims 1 to 18 having ultrasonic cut lateral edges (la, lb), wherein N is an integer > 1, said method comprising the steps of: i) providing a layered sheet having a substantially rectangular shape and comprising: a) two parallel lateral edges (la, lb) each extending in said longitudinal direction and being separated from each other by a transverse width W; b) a first fabric layer (2) comprising fibers of thermoplastic; c) a first coating layer (3) comprising thermoplastic; and said layered sheet having a longitudinal length greater than or equal to L and a transverse width W0 greater than N x W; ii) passing the layered sheet through an ultrasonic cutter having at least one horn (9) and N+1 blades, wherein adjacent blades are separated from each other by a distance W, such that each of the blades cuts into the sheet to simultaneously cut the sheet into the N samples.

23. The method of claim 22, wherein, The method further comprises a step iii) forming one or more through holes (5) in each of the N samples by laser cutting.

24. The method of claim 22, wherein, The ultrasonic cutter has M ultrasonic horn heads, each ith horn head driving K i cutting blades, wherein M and each K i is an integer ≥ 1, and wherein .

25. The method of any one of claims 22-24, wherein, The blades are disc blades having a circular outer peripheral cutting face (10a) and the disc blades roll on the layered sheet during ultrasonic cutting of the samples.

26. The method of any one of claims 22-24, wherein, The layered sheet is passed through the ultrasonic cutter at a forward speed in the range of 2 m / min to 10 m / min, in each horn using ultrasonic waves having a frequency of 30 kHz and a power of 250 W to 350 W for each blade attached to the horn.

27. The method of claim 26, wherein, The layered sheet is passed through the ultrasonic cutter at a forward speed in the range of 3 m / min to 8 m / min.

28. A ring spinning machine having two, four or eight spindles, comprising a ring band according to claim 21, wherein the lateral width W is in the range of 10 mm to 25 mm.

29. The ring spinning frame of claim 28, wherein, The lateral width W is in the range of 10 mm to 20 mm.

Images