FI78510C - Process for coating a substrate with ultrasonic welded wires and machine for carrying out the method - Google Patents

Description

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A method of coating a substrate with ultrasonically welded wires and a machine for performing this method. For example, a substrate with an ultrafiltration precipitate is also used for genomics.

This invention relates to a method of coating a substrate with ultrasonically welded yarns, the yarns and the substrate being at least in part a thermoplastic material, and to a machine for carrying out this method.

CH Patent No. 580,496 has already proposed a method of making a fur fabric, according to which a layer of parallel yarns is successively formed as rows of loops which are then attached to the surface of a substrate by locally melting the material from which the yarns and the substrate are made by pinching them. between the support surface and the sonotrode, the frequency and amplitude of the acoustic vibration of the device being suitable for melting the thermoplastic material. According to this method, the wire layer is folded by a reciprocating mechanism having a speed higher than the speed of the substrate. This mechanism comprises a matrix provided with a plurality of wire guide tubes lined up transversely to the advance of the substrate and mounted to reciprocate in a plane perpendicular to the plane of transition between the welding sonotrode and the welding support surface to form successive parallel strands to the surface of the substrate from areas adjacent to this substrate.

One of the main disadvantages of this solution is that the rows of loops are in a straight line on the substrate, which is not 2 78510 desirable in the case of carpet, as it gives the substrate less opacity and makes joints more difficult, because if the rows are not exactly aligned, is very clear. It is an object of the present invention to provide at least a partial improvement over the above-mentioned disadvantages.

Therefore, the present invention relates, firstly, to a method of coating a substrate with ultrasonically welded wires, said wires and substrate being at least partially thermoplastic material, the method comprising placing said substrate at a welding sonotrode, contacting portions of said wires with a sonotrode portion of this substrate; the contacting parts are pressed against a sonotrode connected to a pulse source to transmit varying ultrasonic compressions which cause local melting between them, and this compression is relaxed to move the substrate and weld another wire portion to another part of the substrate surface, and so on until the substrate is coated. This method is characterized in that said sonotrode is fitted adjacent to the substrate reverse side, each of said yarn passed through the guide tube having the outlet is sonotrode into the adjoining support surface, these guide tubes are moved back and forth in a direction substantially against the transmission surface perpendicular to the sonotrode vibrations, and that the supporting surface nat-applied intermittently to the elastic contact with the substrate on the front of the point, which moves the sonotrode värähtelynlähetyspinnalla mainitul Ia, the respective ends of this portion of the substrate and each of said tubes of said pressing against said finish portion of the wire sonotrode.

The present invention also relates to a machine for carrying out this method, comprising means for a substrate

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3 78510, the wire guide tube matrix, this wire guide tube matrix being arranged transversely to the direction of travel of said substrate and connected to guide members controlling the displacement of this matrix and the actuating members a welding station comprising a sonotrode and support members arranged on both sides of said part of the substrate and pulse devices for this eono-trode to cause it to oscillate at a sound frequency which heats the thermoplastic material to its melting temperature when pressed between this sonotrode and these support members that the displacement control devices are directed perpendicular to the surface of action of the sound vibrations of the sonotrode and that said support members consist of support surfaces located in the immediate vicinity of the outlet ends of said respective control tubes; which tubes are mounted on said matrix by means of elastic suspension means which act at least in the direction of the trajectory of the matrix, bringing said support surfaces against the transmission surface of the vibrations of the sonotrode.

The advantage of the present invention is that it makes it possible to individually select the welding areas of each wire from the substrate, which is not possible with the known method of obtaining only loops aligned in a transverse direction with respect to the substrate. Thus, the method according to the invention makes it possible to produce a product which has a particularly pleasant appearance and which does not differ in any way from a conventional plush mat, but which, compared with a conventional plush mat, offers considerable raw material savings which can be estimated at about 20% of yarn. The method is not limited to mock-type travel. The yarns can be used to coat substrates for wall coverings and all kinds of other applications, for example in the field of geotextiles. As used herein, the term "yarns" is not limited to yarn obtained by spinning staple fibers, but equally refers to nozzle spun and textured filament yarns, fibrous yarns, or multi-filament yarns of large diameter, e.g., about a millimeter thick.

The accompanying drawing shows very schematically and by way of example an embodiment and variations of the machines for carrying out the method according to the invention, as well as various finished products.

Figure 1 is a perspective view of this embodiment.

Figure 2 is a plan view of a detail of Figure 1.

Fig. 3 is a sectional view taken along line III-III in Fig. 2. Figure 4 is a side elevational view of a variation of Figure 1.

Figure 5 is a perspective view of a variation of Figure 1. Figure 6 is a partial vertical sectional view of another variation.

Figure 7 is a partial vertical sectional view of another variation.

Figures 8 and 9 are plan views of products made with a variation of Figure 5.

Figure 10 is a partial perspective view of another variation.

Figure 11 is an enlarged perspective view from another angle seen in detail from Figure 10.

The machine shown in Fig. 1 comprises a sonotrode 1 connected to an oscillation generator 2 comprising a non-transducer, the fixed support 3 supporting this assembly. The matrix 4 containing the tubes 5 is mounted to slide between two parallel sliders 6, the longitudinal axes of the tubes being parallel to the sliders 6 78510 and perpendicular to the substrate formed by the substrate 7, which is generally a nonwoven or woven fabric at least partly of thermoplastic material, on which the loops are to be welded to make a mocha-type mat. connected to a drive motor 9 of the receiving roll 8 transfers the substrate 7 of the sonotrode 1 and the pipe between the outlet of arrow F direction. At the inlet ends of these tubes 5 come corresponding wires 10 which are to form loops 11 on the surface of the base 7. These yarns 10 are at least partially of a thermoplastic material and come from feed sides (not shown). As shown in Fig. 3, each tube 5 has a neck ring 5a arranged inside the matrix 4, and a spring 16 resting against this neck ring 5a and the top wall of the matrix 4 presses the elastic tubes 5 towards the base 7. These springs 16 are dimensioned so that the compression is applied evenly to all the wires 10 welded simultaneously.

The tube matrix 4 is connected to the drive motor 12 by a rotary shaft, Gella 13, one end of which is connected to the center of the matrix 4 and the other end to an eccentric 14 fixed to the traction wheel 15, which is wedged in the output shaft of the motor 12. Preferably, the tubes are attached to the matrix 4 so that they are not all aligned in the same axis perpendicular to the direction of travel of the substrate 7, as seen in particular in Figure 2. Because welding of the respective wires occurs when these wires are pressed between the outlet end edge of each tube the base, in turn, is pressed against the sonotrode 1, which transmits its vibrations to it, with the result that the loops 11 are laterally offset exactly depending on how the tubes 5 are placed in the matrix 4. The arrangement shown in Figure 2 is of course not limiting and other arrangements can be chosen .

The cycle of forming and fixing the row of loops 11 comprises raising the matrix 4 of the tubes 5 by means of a rotating rod 13.

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As a result, the tubes 5 slide on the substrate 7 relative to the respective wires welded above. The matrix 4 of tubes 5 then returns towards this substrate 7, which has advanced one step corresponding to the distance between the ends of the loops 11 connected to the substrate, and elastically presses the exit ends of these tubes 5, the matrix 4 being slightly larger than the distance separating the tube ends from the substrate 7. , the difference is absorbed by the springs 16 connected to the tubes 6. This allows contact between the wires 10 to be welded, the part of the substrate 7 to which the wire 10 is welded and the sonotrode 1 from a fraction of a second to about one tenth of a second sufficient for welding the substrate 7 and the wire 11 by ultrasonic vibration . This time, which can vary from a few hundredths of a second to a few tenths of a second, and the compression can be adjusted by adjusting the compression of the spring and the trajectory of the tubes 5, this mainly depending on the roughness of the wires or filaments and the quality of the substrate.

The variation shown in Fig. 4 has a tube matrix 17 to which each tube 18 is connected by an elastic arm 19 having a stop portion 20 projecting perpendicular to the longitudinal axis of the elastic arm 19 parallel to the sliding direction of the matrix 17. The rotary selection member 21, provided with a series of radial pallets 22 of different lengths, is connected to the drive mechanism of the machine (not shown), whereby it moves forward one step with each revolution of the traction wheel of the matrix 17. Such a traction wheel corresponds to the wheel 15 of Figure 1.

The fan 23 is arranged at the point of the track formed by the wire 10 between the outlet of the pipes 18 and the base 7. This fan ensures that the wire loops 11 always form in the same direction during the downward movement of the tubes 18. During the ascending period of the reciprocating motion of the matrix 17, the stops 20 meet the radial pallets 22, limiting the trajectory of the respective tubes 18 and 7 78510 as a result of the sliding distance between the tubes 18 and the respective yarns 10. As a result, when the tubes 18 are led in the direction of the base 7 to form the loops 11, the value of the slip between these tubes and the wires 10 determines the height of the loops 11. By appropriately programming each tube 18 separately, it is thus possible to provide embossing on the surface of the substrate 7. This is an additional advantage of the machine according to the invention, since the embossed mocket has a considerable share of the market. The rather simple simplicity of the operating devices should also be emphasized, despite the fact that the machine according to the invention represents a considerable improvement over the prior art. Of course, it is possible to use devices commonly used in plush machines to form loops of different heights, such as mechanisms equipped with photoelectric readers.

The variation shown in Fig. 5 relates to a mechanism in which the matrix 4 of tubes 5 makes not only a vertical reciprocating movement as in the case of Fig. 1, but also a reciprocating reciprocating movement with respect to the substrate 7. To this end, a circular cam 24 is mounted for rotation about an axis parallel to the longitudinal axis of the base 7. The sensor 25 presses against this cam 24 by the action of the spring 26. This sensor is connected to the slider 6 and its cam-side end is guided horizontally on a rail 27 transverse to the base 7. The circular cam body 24 is synchronized by means of transmission parts (not shown) with the connecting rod 13 (shown in Fig. 1) so as to move transversely slider 6 back and forth between successive welds of the same wire.

Arranged transversely to the base 7 is a jaw 28 with teeth 28a formed of vertical plates, the distance between which corresponds to the distance between the tubes 5 of the matrix 4. These teeth 28a are at the center of the transverse trajectory of each tube, whereby the welding of the same wire 8 78510 takes place alternately on different sides of the same tooth 28a. With this variation, different models can be implemented depending on the placement of the tubes 5, the extent of their transverse movement and the relative speed of the substrate. Two examples of such patterns are shown in Figures 8 and 9. These figures show in bold the two-row arrangement of the tubes 5 in the matrix at the time of departure and in solid lines, dashed lines, respectively, the wires from the tubes of each row. The jaw shown in Fig. 5 can, of course, also be used in connection with the mechanism according to Fig. 1, in which case the teeth of the jaw then prevent the loops of one longitudinal row from penetrating the adjacent rows.

It should also be noted that the described method, in particular the variant according to Figure 5, can also be used to fasten the yarns to the substrate without forming loops, holding the yarns continuously against the substrate. For this, it is sufficient to omit the teeth 28a of the jaw 28 and to adjust the extent of the reciprocating movement of the matrix 4 to coincide with the advancement of the base, whereby the wires are pulled parallel to the surface. For example, wall coverings can be prepared by this method.

Figure 6 shows another variation of Figure 5. This variant further comprises a slider 6, tubes 5, a jaw 28 with teeth 28a, a base 7 and a sonotrode 1. The jaw 28 has rings 29 guiding wires 30 which are passed longitudinally through loops formed on both sides of the teeth 28a by reciprocating movement of the tubes 5.

Fig. 7 shows a variation in which loops are formed over the teeth 28a of the jaw 28, as in the case of Fig. 5. Each tooth 28 of this jaw has a blade 31 connected to the return spring 32. Each time the matrix 4 of the tubes 5 descends to bring the wire into contact with the base 7 and the sonotrode 1, the blade 31 descends and cuts the wire tooth 28a over the newly formed loop.

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Experiments performed with the method according to the invention have shown that different thermoplastic materials can be welded together. For example, a substrate of polypropylene for a yarn of polypropylene, a substrate of polyamide-6 for a yarn of polyamide-6, a substrate of polyamide-6 for a yarn of polypropylene. Of course, the quality of the material immediately subject to welding is important. However, this does not preclude the use of bicomponent filaments having a polyamide-6 coating and a polyester core, such filaments are commercially available. Likewise, one surface of a non-thermoplastic material, for example a jute fabric, can be coated with a coating of thermoplastic material suitable for the wire to be welded to its surface. The substrate of a thermoplastic material can also be coated with a thermoplastic material of the same or different type which is well suited for the wire to be welded. Thus, for example, a powdery substance may be incorporated into a nonwoven substrate, for example to thicken this substrate.

Although Figures 8 and 9 show patterns obtained with matrices in which the tubes are divided into two parallel rows transverse to the substrate to cross the wires, it is of course also possible to implement patterns obtained with one or more separate matrices with a single row of tubes. , which move back and forth in a direction transverse to the direction of travel of the substrate, forming dashed lines.

When welding wires consisting of many filaments pressed through a spinning nozzle with several nozzles, these filaments may more or less spread at the welding points because they are not bonded to each other like in spinning wires. It has been found that welds of multifilament wires made with the machines shown in Figures 1 to 7 have a good tensile strength of about 6 mN, but that they, on the other hand, behave much worse in the "fluff test", after which it is stated that a considerable number of filaments have come off. Such a defect makes the product virtually unsuitable for use in floor coverings.

Various experiments have been performed to remedy this disadvantage. Thus, for example, the longitudinal axis of the tubes is inclined with respect to the sonotrode 1. When this inclination was chosen because the part of the edge of the tube along which the protruding wire passes would be brought into contact with the substrate first, it was found that the tensile strength of the weld increased but the "fluffing phenomenon" remained unchanged. When the tube was tilted symmetrically with respect to the vertical, the tensile strength decreased and the "fluff phenomenon" remained noticeable.

Examination of the welding under a microscope shows that by using the edge of the tubes 5 as a support surface for pressing the wires against the substrate 7 and the sonotrode 1, the annular shape of this support surface prevents wire filaments which are more or less detached only when the wire is curled together. the spread. When the wire comes from the tube resting on a concave surface and when the support surface during welding is formed by an annular portion of the tube end bounded by this particular concave surface, this shape causes the filaments to focus on the support surface. This concentration of filaments causes the wire, which can be compared to a broken cylinder, to have more filaments in the center of the annular sector dominating the weld than at its edges. Thus, the thickness of the material is greater at the center of this annular sector than at its edges. The compression is then uneven and the filaments at the edges of this sector in particular weld less to the substrate, resulting in a significant "fluffing effect", despite the good strength of the weld itself, which was tested by a tensile test on the whole wire.

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In particular, this deficiency is proposed to be remedied by the variations shown in Figures 10 and 11. This variant further comprises a matrix 34 provided with a series of wire guides 35 arranged alternately in two rows transverse to the longitudinal axis of the base 7. These wire guides 35 have the same function as the tubes 5 of the previous embodiments. In this case, the wire 10 simply does not pass through the arm 36, but through a tube 37 which passes through a parallelepiped-shaped body 38 attached to the lower end of the guide arm 36. Each parallelepiped-shaped body 38 is fitted between the two teeth 28a of the above-mentioned jaw. The lower surface of each parallelepiped-shaped body 38 has a rectilinear protrusion 39 arranged transversely to the direction of travel F of the base 7 substantially laterally to the edge of the outlet 40 in the lower surface of the parallelepiped-shaped body 38 and after the outlet 40 of this tube 37 to the front of the base 7. This protrusion 39 preferably consists of a half-ellipse with a major axis parallel to the lower surface of the body 38. It is equally possible to use a flat-faced embossment flanked in the longitudinal direction by two circular arcs.

This straight-forward embossment 39 forms a support base for the wire 10 when this wire is welded to the base 7 by pressing the parts of the wire and the base to be welded against the sonotrode 1. As seen in Fig. 11, the multifilament yarn 10 coming from the tube 37 resting against a concave surface formed by one sector of the outlet 40 immediately passes along a rectilinear protrusion 39 which bends the yarn 10 convex. Furthermore, when this embossment 39 is rectilinear, the filaments of the yarn 10, which are somewhat detached from each other because they are not twisted, can spread to this rectilinear embossment 39. The filaments are well distributed on the embossment 39, which forms the support surface of the yarn 10 on the substrate 7 when welding, the welding is made smoother and thus the “lapping phenomenon” can be considerably reduced.This variant is therefore particularly advantageous when producing mocha-type mats whose wear is mainly due to this “lapping phenomenon.” In addition, this variant has all the other advantages of the invention mentioned above.

Claims (11)

A method of coating a substrate with trees welded by ultrasound, the trees and the substrate being at least part of a thermoplastic material, according to which the substrate (7) is placed adjacent to a welding sonogram (1), portions of said trees being brought in contact with the part of the substrate which is adjacent to the sonotrode, these in contact with each other standing parts of the substrate and trees are pressed against the sonotrode (1), which is connected to an impulse source (2), so that varying ultrasonic pressure can be conveyed to these. between them, local melting occurs, and this pressure is reduced to move the substrate (1) and to weld another tree section (10) to another part of the surface of the substrate and so on until the substrate has been coated, characterized of said sonotrode (1) being arranged adjacent the back side of the substrate (7), that each of said trees (10) is passed through a guide tube (5, 18, 37), the exit opening of which is adjacent a a dead surface at the location of the sonotrode (1), that these guide tubes (5, 18, 37) are moved back and forth in a direction substantially perpendicular to the transmission surface of the sonotrode's oscillations, and that these support surfaces are intermittently brought into elastic contact with the the portion of the front face of the substrate moving along said surface where the sonotrode (1) emits oscillations, to oppose the sonotrode (1) pressing this portion of the substrate (7) and any such tree portion (10) coming from the corresponding tube end (5) , 18, 37). i7 7 8 51 0 A method according to claim 1, characterized in that said guide tube (5) is transversely moved in a direction with a distance which separates from each other the two surfaces of the deca supporting surfaces with the opposite side of the substrate (7) moving on the sonotrode (1), and then these guide tubes (5) are then transversely moved in a second direction, spaced apart from each other, the following contacts between these support surfaces and the detached side of the substrate (7) moving on the sonotrode (1) . Method according to claim 2, characterized in that each tree (10) is always caused to run across two successive contacts with the substrate (7) over a guide (28a), the height of which corresponds to the desired height of the tree loop. 4. A method according to claim 1, characterized in that said guide tubes (5, 18, 37) are made to produce and eat yawning movement, the extent of which is greater than the movement distance of the substrate (7) between the two successive contact surfaces of said support surfaces and which depends on the desired height of the loop, and to form an air flow which is of the same direction as the direction of movement of the substrate (7), and which is directed towards the tree portions which are between the substrate and the exit ports of the guide tubes. 5. A method according to claim 3, characterized in that trees are fed longitudinally relative to the substrate under the loops formed along each guide (28a). Method according to Claim 3, characterized in that the loops formed on the guide (28a) are cut as they leave this guide. 18 7851 0 A machine for applying the method according to claim 1, which comprises means (8, 9) for moving the substrate (7), a tree guide matrix (4, 34) arranged transversely in the direction of movement of said substrate (7). and connected to the control means (6) which determine the movement of this matrix (4, 34), and to the driving means (12, 13, 14, 15) which provide a forward and eaten movement in relation to the control means and which cause the exit ports of the guide tubes (5, 18, 37) one after another adjacent to a portion of the substrate (7), and a welding station comprising a sonotrod (1) and support means arranged on each side of said part of the substrate (7), and for this sonotrode (1) impulse means (2) to cause it to vibrate at a sound frequency that heats the thermoplastic material to its melting temperature as the material is pressed between the sonotrode and said support means, characterized in that the control means (16) for movement angled perpendicular to the impact surface of the sonotrode (1) sound oscillations, and said support means consists of support surfaces located in the immediate vicinity of respective guide tubes (5, 18, 37), which tubes are mounted in said matrix (4, 34). ) by means of elastic suspension means which act at least in the direction of the path of movement of the matrix and which bring said support surfaces towards the transmission surface for the oscillations of the sonotrode (1). 8. Machine according to claim 7, characterized in that the support surfaces are distributed on the matrix (4, 34) alternating along at least two parallel axes, which are directed transversely to the path of movement of said support. 9. Machine according to claim 7, characterized in that the suspension means (19) act in each direction of the movement path and under the influence of the select means (22) to limit the return movement path of the respective control tubes (18) to a predetermined value, which depends on the desired loop. length.