EP2984224B1 - Method for producing an industrial fabric - Google Patents

Description

The invention is based on a method for producing an industrial fabric, which can be used for example in various positions in a machine for producing a fibrous web such as a paper, board or tissue web or for the production of non-wovens, according to the preamble of claim 1.

Fabrics for large industrial installations such as paper machines or machines for the production of non-wovens products are usually made of a polymeric monofilament yarn from which, for example, by weaving or spirally winding a sheet is produced. This gives a support structure which should meet certain requirements for properties and functions in order to enable the production of the respective degree of paper. The support structures support the fibrous web as it passes through the fibrous web machine.

In such a machine for producing a fiber web, there are usually several different sections which fulfill different tasks during the manufacturing process. Different requirements are therefore placed on the clothing, which are reflected in different characteristics. Some fabrics have a permeable, flexible structure to allow liquid to pass through while draining the cellulosic fibers of the fabric and begin to form the fibrous web. Other fabrics are less complicated in construction and have a higher air permeability. Dryer screens transport the paper web through the dryer section while allowing the removal of water vapor during the drying process.

Woven structures can also be made to have some degree of topography or structure on the paper facing side. This may be in the form of a machine direction or cross machine direction dominant pattern of line fields or in the form of a single pattern or motif.

During the manufacturing process, the surface structure of a fabric can be transferred to the paper web, so that a permanent structure in the finished product is visible.

A significant disadvantage of using weft or warp yarns in making such topographical patterns is the complexity of the weave patterns to create a particular visual or structural impression. For the fabric manufacturing process, this means sacrificing manufacturing time efficiency, higher cost, design freedom and the balance between functionality and aesthetics of the fabric, as well as higher reject rates due to the complex patterns. Line-shaped patterns are also limited to machine direction, cross-machine direction or twill weave.

Such patterns as well as the methods for their production have long been known in the art from a variety of variations.

For quite some time, patterns on the surface of clothing have also been produced by printing, for example, with a polymer which is applied to the clothing by means of various processes and fixed. So it is from the EP2304104B1 For producing a topographical pattern of polymer material on an endless belt, it is known to use a rotary screen whose cylindrical surface has a perforation pattern defining the topographical pattern, which is viewed in the circumferential direction of the lateral surface by a perforation pattern section or by a plurality of successively identical perforation pattern sections. To generate the On a peripheral side of the endless belt, the polymer material is pressed in a liquid or pasty state through perforations of the peripheral surface of the rotary screen, while the rotary screen, rotating about its longitudinal axis, rolls on the peripheral side of the endless belt in a continuous circulating path.

Likewise also reveals the DE 10 2005 006 738 A1 a method in which a topographical pattern is produced by means of a rotary screen on a papermachine fabric.

WO 03/040470 discloses a screen with a textile fabric on which are applied groups of beads of a polymer material, the beads beginning at points of origin and terminating at end points remote from the starting points. This document further discloses that end points of the at least one group of beads are spaced from starting points of at least one further group of beads, whereby blank areas are created between the groups on the surface of the sheet and that the beads can be applied by extrusion. The EP 1 818 448 discloses a forming wire which is made by applying polymer material to a fabric by means of an applicator head, the applicator head having an exit opening in the form of one or more spray nozzles. The WO 00/75424 discloses a papermaking belt which is made by applying polymeric material to zipper or serpentine lines by means of two extrusion dies on a fabric, for example.

Combinations of topographical weave patterns and printed patterns that overlay the weave pattern are also known, for example from the EP1242681B1 , Herein is described a fabric used in a papermaking machine for forming a pattern on a tissue paper. The fabric comprises a load-bearing layer defining a first plane and a forming layer interwoven with the load-bearing layer defining a second plane spaced from the first plane, the upper side having a background texture defined by the load-bearing layer Layer and the mold layer is defined. A polymeric strand is disposed on the upper side in a decorative thread-like pattern with the background texture appearing where the pattern formed by the polymeric strand does not appear.

The mentioned methods have several disadvantages. Thus, it is disadvantageous in the rotary screen method that no longer polymeric structures can be produced if the size of the screen is to be moved within manageable limits. The combined fabric and polymer patterns are complicated to manufacture. Also, the freedom of design in terms of dimensioning of the polymer order is not guaranteed, but this is limited by other limiting factors such as the screen thickness and thus not feasible for all applications in a desirable manner. It is e.g. It is not possible to apply polymer of any thickness or height above the sieve surface, as the material thickness is related to that of the sieve.

In addition, it is not possible to change the design of the polymer application over the expansion of the fabric when using the screen printing process, although it would be desirable in many cases, for example, to apply in edge regions opposite to the middle part of the fabric different polymer application.

It is accordingly an object of the invention to mitigate or avoid the disadvantages of the prior art and to provide a method for producing an industrial fixture and an industrial fixture, which is on the one hand prepared so that the basic physical properties such as dimensional stability and air permeability are guaranteed and on the other hand pattern can be applied to the fabric in a simple manner in the desired shape and number.

The object is achieved with regard to the method by the features of claim 1.

According to the invention it is provided that in a first process step, the production of a sheet of yarns in the form of a fabric, Geleges, knitted fabric, knitted or made of interconnected spiralized elements. In a second method step, at least one polymer material is applied to at least one surface of the sheet in the form of at least one group of beads, wherein the polymer application starts at starting points and ends at end points remote from the starting points. This process step is repeated as often as desired, wherein end points of the at least one group of beads are spaced from starting points of at least one further group of beads, whereby blank regions between the groups on the surface of the sheet are produced.

According to the invention, it is further provided that the polymer is applied by means of several application nozzles and the application nozzles are controlled individually or in sets and thus the polymer application of the individual application nozzles or sets of application nozzles is switched on or off independently and regulated.

As a result, on the one hand arbitrarily long and any number of beads in any patterns, combinations and shapes can be made, on the other hand, are interrupted at random intervals and thereby define empty areas, thereby creating space for more patterns, motifs, logos, etc., in another Process step or can be introduced simultaneously with the beads in a simple manner in the void areas. Pattern combinations in any variety and with almost infinitely adjustable properties for the end product in terms of strength, thickness, air permeability, etc. are thereby possible. By applying a jet, both short and arbitrarily long beads can be applied without special technical effort. Because the application nozzles are controlled individually or in sets, the polymer application of the individual application nozzles or sets of application nozzles can be switched on and off independently and / or regulated.

According to an advantageous aspect of the invention, all the caterpillars have a length which corresponds to at least twice their maximum width. As the width of the bead can be taken, for example, the width of the surface of the fabric.

Preferably, the polymer is applied by several application nozzles simultaneously. Any number of simultaneously operated application nozzles can be envisaged. In a particularly preferred embodiment, the polymer is applied by means of 5 to 100 application nozzles simultaneously. The plurality of application nozzles can be arranged, for example, in the cross machine direction next to each other and have a fixed distance from each other. This distance may be the same or different for all application nozzles. Advantageous distances between the application nozzles are between 0.5mm and 20mm.

For the purposes of the invention, a set comprises several, preferably between 2 and 50 applicator nozzles. An application nozzle can always only belong to a maximum of one set. The application nozzles of a set can either be directly adjacent, have fixed distances to each other, such as every tenth or twentieth nozzle. But it is also possible that a set includes an irregular selection of application nozzles.

The control of the application nozzles in sets has economic advantages. For example, to control 100 application nozzles grouped into 10 sets, only 10 valves are needed.

According to an advantageous aspect of the invention, the beads and / or the blank areas may be formed in the form of patterns.

Preferably, the beads are applied along paths. The individual paths run uniformly and in the cross machine direction next to each other. There is a gap between two adjacent paths, which remains essentially constant along the course of the path. Fluctuations can occur within the scope of manufacturing accuracy. In a particularly preferred embodiment, all distances between the paths are the same size.

The paths are to be understood as grid lines on which the polymer beads are deposited. Some of the paths can be completely covered with polymer. Other paths contain one or more empty areas between the individual caterpillars. The possibility that individual paths remain entirely without polymer application can also be provided.

Particularly preferably, the paths may be straight, wavy or jagged. However, other variants of a uniform course are conceivable.

Preferably, the paths may be the full length of the scope of industrial equipment. There is also the possibility that the paths have an even greater length to multiple times the amount of industrial voltage. This is the case, for example, with a spiral circulation of the paths. Thus, a spiral course of the paths is conceivable, for example, in that the holder with the application nozzle or application nozzles is moved during the application in the cross-machine direction so that it is offset by one width of the industrial fabric tension in the cross-machine direction.

It is also advantageous if the pattern is constructed from at least one digital image motif. In the context of this application, a motif is to be understood as a digital image motif which, in analogy to conventional digital images, consists of a finite number of discrete color values. A digital image motif according to the invention is formed from caterpillars and empty areas. The caterpillars correspond to linear color spots and the empty areas white spots. If only one type of caterpillar is used, the digital picture will look like a black and white picture. When using different caterpillars, the digital image motif is analogous to a digital image with multiple gray levels.

The digital image has an extension in the machine direction and cross machine direction. It forms the core of the pattern. The pattern itself is created by a repetition of the at least one image motif. In a preferred embodiment, the pattern is created by tiling the entire surface of the industrial fabric, or at least portions thereof, through the digital image motif.

In a preferred embodiment, the digital image motif extends in the cross-machine direction over at least two beads and / or empty regions or over at least two paths. In a particularly preferred embodiment, the digital image motif extends over at least three beads and / or empty regions or over at least three Paths and, in a most preferred embodiment, the digital image motif extends across at least five

Caterpillars and / or empty areas or over at least five paths before a repetition of the motif begins.

In a further advantageous embodiment, the extent of the digital image motif in the cross-machine direction is at most 10%, preferably at most 5% of the width of the industrial clothing is before a repetition of the motif begins.

According to the two preferred embodiments just described, the digital image motif in the cross-machine direction is therefore significantly wider than a single bead. However, it is still small in the sense that it can often be placed across the width of the industrial fixture, for example more than 10 times or more than 20 times, compared to industrial fixturing.

In a further preferred embodiment, at least two types of beads, which differ in at least one of the parameters material, cross-sectional shape and cross-sectional size, are applied to the industrial adhesive. These different beads can lead to different or different effects in the fibrous web. It can be used for functional or decorative purposes. A digital image motif, which is constructed for example of empty areas as well as two types of caterpillars, can thus be understood as a three-color image motif.

Advantageously, the polymer may be a silicone, a polyurethane, an epoxy resin or an ester. The substances mentioned are easy to handle in their workability and their durability and are available in large quantities.

It can preferably be provided that the polymer is connected in a form-fitting and / or materially bonded manner to the surface of the fabric. This ensures that the caterpillars adhere securely and the covering can be used for a long time without chipping off material.

According to an advantageous aspect of the invention can be provided that the beads are formed flush with a surface of Industriebspannung. This is particularly advantageous for forming fabrics for the production of watermarks.

According to an alternative advantageous embodiment variant, however, it can also be provided that the beads project beyond the surface of the industrial fabric in a z-direction. As a result, the embossed structuring of the fibrous web is more clearly visible.

The height of the caterpillars in the z-direction is preferably up to 2 mm. In other advantageous embodiments, the height of the beads in the z direction can be up to 5 mm. This makes it possible to create clear and sharply demarcated, deep in the fiber web embossed structures.

A ratio between the height in the z-direction and the width of the beads may preferably be between 0.5: 1 and 2: 1, preferably 1: 1. Deviations from this can lead to instability of the caterpillars, damage and spalling, which can affect the quality of the final product.

Fig. 1 bis 3

Ausführungsbeispiele, in denen Raupen erfindungsgemäß entlang von Pfaden abgelegt sind und das Muster durch Wiederholung eines digitalen Bildmotivs gebildet wird.

The invention will now be described by way of example with reference to the figures. In the figures show:

Fig. 1 to 3

Embodiments in which beads according to the invention are stored along paths and the pattern is formed by repeating a digital image motif.

In the FIGS. 1 to 3 are highly schematic embodiments of patterns 6 shown, which are applied to a non-illustrated industrial tension. In each of the three figures, only a small section of the pattern 6 is shown, which is repeated further in the machine direction 7 as well as perpendicular to it in the cross machine direction.

According to the invention, the patterns 6 result from a regular repetition of a digital image motif 5. The image motif 5 in the three figures consists respectively of beads 1 and empty regions 3.

The caterpillars 1 are in the FIGS. 1 to 3 each filed along paths 10. In Fig. 1 and Fig. 3 the paths are straight along the machine direction 7, in Fig. 2 The paths 10 also run jagged essentially in the machine direction 7. The paths 10 can also be wavy or in other shapes. In further embodiments according to the invention, the paths 10 run at a slight angle to the machine running direction 7. Thus, it can be achieved, for example, that the paths 10 spiral around several times around the industrial clothing. On such paths 10 and caterpillars 1 can then be stored, which are longer than the scope of industrial voltage.

The paths 10 have in Fig. 1 to Fig. 3 all the same distance 4 from the respective neighboring path. The distance 4 remains in the jagged paths 10 in Fig. 2 constant over the entire length of the path 10, apart from small fluctuations due to the production technology. But there is also the possibility that the paths 10 have different distances between them.

The beads in a digital image motif 5, as shown in Fig. 1, all have the same length. The Fig. 2 and Fig. 3 However, also show embodiments of the invention in which the caterpillars 1 have different lengths. Empty areas 3 in the digital image motifs 5 arise due to interruptions 2 of the tracks 1.

In Fig. 1 and Fig. 2 For example, the digital image motif 5 has a width in the cross machine direction of eight paths. Fig. 3 shows a digital image motif 5 with a width of five paths 10, wherein on a path 10 no beads 1 are stored.

Industriebespannung can, for example, a forming fabric, a press felt base fabric, a dryer fabric, a transfer belt or any other arbitrary Be covering. The said fabrics can be arranged in machines for producing a paper, board or tissue web or in machines for producing non-wovens in various positions. As already mentioned above, depending on the position, different requirements are placed on the covering, with regard to their water permeability, tensile strength, resilience, open volume, etc.

The fabrics may be formed in a well-known manner in the form of woven or non-woven structures. Typically, the fabrics forming the fabrics are made by interweaving warp and weft yarns that intersect each other. Also, coverings that consist entirely or partially of non-woven components such as laid, knitted or knitted are known and suitable for the application of the measures according to the invention. Likewise, the fabrics may be made by spirally winding banded material or yarn sheets. Finally, the formation of clothing by the connection of spiral structures by means of plug wires is known, the latter being common especially in the field of dryer fabrics. The fabrics can be combined in a known manner with other components such as staple fiber layers or polymeric portions in the form of films or particles to further model the property profile.

The pattern 6 or quasi-pattern, which is applied repetitively or without specific repetition on at least one surface of the textile fabric, consists of beads 1 of a polymeric material such as silicone, polyurethane, epoxy resin or esters.

Each of the beads 1 has a certain length L between a starting point and an end point of the respective bead 1. The interruptions 2 are in each case between end points of one or more caterpillars 1 and starting points of further caterpillars 1. The empty regions 3 can assume any desired shapes, depending on how the spacing of the individual caterpillars 1 from each other is applied. It can Pattern 6, quasi-patterns or arbitrary arrays of void areas 3 are generated.

In a further step of the production process, these empty areas 3 can then be provided with a further polymeric pattern, which can be, for example, a personalized motif or a logo.

The pattern 6 can be selected according to aesthetic and / or useful aspects, which influence the latter, for example, the physical properties of the fiber web.

The topography of the caterpillars 1 may vary depending on the particular area of application of the clothing as well as the thickness and grammage of the product. The caterpillars 1 can lie in the plane of the clothing surface or project them by a certain height in the z-direction of up to 5 mm. The width of the beads 1 depends on the height in the z-direction. Typically, the height to width ratio will range from about 0.5: 1.0 to 2: 1. Usually, a ratio close to 1: 1 is preferred in order to ensure an optimal shape of the beads 1. The distances between the individual beads 1 are preferably at least as large as their width.

The polymer adheres to the surface of the fabric by a combination of positive engagement and material bond. The positive connection is achieved with the threads of the textile fabric by flowing around with polymer. Optionally, the material combination of fabric and polymer can also chemically connect with each other and thereby allow a material bond. A pretreatment of the fabric for the purpose of better adherence of the polymer to the fabric, for example by plasma activation is also possible.

Claims (15)

1. Method for manufacturing an industrial clothing, in particular a clothing for a machine for manufacturing a fibrous web, such as a paper, cardboard, or tissue web, or a non-woven product, the method comprising the following method steps: i) manufacturing a planar structure from yarn in the form of a woven fabric, a cross-laid structure, a knitted fabric, a warp-knitted fabric, or from interconnected helical elements; ii) applying at least one polymer material in the form of at least one group of beads (1) to at least one surface of the planar structure, the application of the polymer commencing at starting points and terminating at terminal points which are remote from the starting points; iii) repeating step ii), wherein terminating points of the at least one group of beads (1) are spaced apart from starting points of at least one further group of beads (1), on account of which regions with a void (3) between the groups on the surface of the planar structure are generated, characterized in that the application of polymer is performed by means of a plurality of application nozzles and the application nozzles are actuated individually or in sets, and the application of polymer of the individual application nozzles or of the sets of application nozzles thus is individually activated or deactivated, respectively, and regulated.
2. Method according to Claim 1, characterized in that the length of the individual beads (1) is at least double the maximum width thereof.
3. Method according to Claim 1 or 2, characterized in that the application of polymer is performed by means of 5 to 100 application nozzles.
4. Method according to one of Claims 1 to 3, characterized in that the sets comprise between 2 and 50 application nozzles.
5. Method according to one of Claims 1 to 4, characterized in that the beads (1) and/or the regions with a void (3) are applied in the form of a pattern (6).
6. Method according to one of Claims 1 to 5, characterized in that the beads (1) are applied along tracks (10) in such a way that the individual tracks (10) run in a uniform manner and in the machine cross direction in relation to the in each case mutually adjacent tracks (10) have a spacing (4), preferably the same spacing (4) for all tracks (10), which spacing remains substantially constant along the profile of the tracks.
7. Method according to Claim 6, characterized in that the tracks (10) run in a straight, undulated, or zigzag manner.
8. Method according to one of Claims 6 or 7, characterized in that the length of the tracks (10) is up to the full length of the circumference of the industrial clothing or is a multiple thereof.
9. Method according to one of Claims 5 to 8, characterized in that the pattern (6) is constructed from at least one digital image motif (5) which is formed by the combination of beads (1) and of regions with a void (3), wherein the beads (1) correspond to line-shaped color points and the regions with a void (3) correspond to white spots, and wherein the digital image motif (5) has an extent in the machine running direction (7) and the machine cross direction, and the pattern (6) is created by repeating the at least one digital image motif (5), preferably by way of tessellation of the entire surface or parts of the surface of the industrial clothing using the digital image motif (5).
10. Method according to Claim 9, characterized in that the extent of the digital image motif (5) in the machine cross direction prior to a repeat of the motif commencing is at least two, preferably at least three, particularly preferably at least five beads (1) and/or regions with a void (3) or tracks (10), respectively.
11. Method according to Claim 9 or 10, characterized in that the extent of the digital image motif (5) in the machine cross direction prior to a repeat of the motif commencing is at maximum 10%, preferably at maximum 5% of the width of the industrial clothing.
12. Method according to one of Claims 1 to 11, characterized in that at least two types of beads (1) are applied, which differ in at least one of the parameters of material, cross-sectional shape, and cross-sectional size.
13. Method according to one of Claims 1 to 12, characterized in that the polymer is a silicone, a polyurethane, an epoxy resin, or an ester.
14. Method according to one of Claims 1 to 13, characterized in that the beads (1) protrude above the surface of the industrial clothing in a direction z.
15. Method according to Claim 14, characterized in that a ratio between the height in the direction z and the width of the beads (1) is between 0.5:1 to 2:1, preferably 1:1.

Images