Patent Application
20180220726
The invention pertains to a method for manufacturing an industrial clothing which may be used for example in various positions in a machine for manufacturing a fibrous web, such as a paper, cardboard, or tissue web, or else for manufacturing non-wovens, and to an industrial clothing which is manufacturable by a method of this type.
Clothings for large-scale industrial plants such as paper machines or machines for manufacturing non-woven products are usually manufactured from a polymer monofilament yarn from which a planar structure is generated for example by weaving or coiling. On account thereof, a carrier structure which is to correspond to specific requirements in terms of properties and functions in order to enable manufacturing of the respective paper quality is obtained. The carrier structures support the fibrous web while the latter runs through the fibrous-web machine.
A plurality of various sections which during the manufacturing process fulfill various tasks are usually present in a machine of this type for manufacturing a fibrous web. Therefore, various requirements which are reflected in various features are thus set for the clothings. Many clothings have a permeable and flexible structure, so as to enable liquid to pass through during de-watering, while the cellulose fibers of the material are simultaneously oriented and commence forming the fibrous web. Other clothings are less complicated in their construction and have higher air permeability. Drying wires convey the paper web through the dryer section and simultaneously permit dissipation of water vapor during the drying process.
Woven structures may also be manufactured such that they have a certain degree of topography or structure on that side that faces the paper. This may be in the form of a pattern of line elements which is dominant in the machine direction or in the machine cross direction, or in the form of a single pattern or motif.
The surface structure may be transferred from a clothing to the paper web during the manufacturing process, such that a permanent structure is visible in the finished product.
A significant disadvantage when using weft or warp threads in the manufacture of such topographic patterns lies in the complexity of the weaving patterns for generating a specific visual or structural effect. In terms of the manufacturing operation of the clothing, this means losses in time efficiency during manufacture, higher costs, limitations with respect to the freedom of design and the balance between functionality and aesthetic considerations in the clothing, and higher reject rates on account of the complex patterns. Moreover, line-shaped patterns are limited to the machine direction, the machine cross direction, or to a twill weave.
Patterns of this type and the methods for generating the same have been known in the prior art in a multiplicity of variations for a long time.
For some time, patters on the surface of clothings are also generated by printing, for example using a polymer which is applied to the clothing by means of various methods and fixed thereon. In this way, it is known from EP2304104B1 to use a rotary screen for generating a topographic pattern from a polymer material on an endless belt, the cylindrical sleeve face of said rotary screen having a perforated pattern which determines the topographic pattern and which, when viewed in the circumferential direction of the sleeve face, is formed by a perforated pattern portion or by a plurality of perforated pattern portions which lie in sequence and are mutually identical. In order for the pattern to be generated on a circumferential side of the endless belt, the polymer material in a liquid or pasty state is squeezed through perforations of the sleeve face of the rotary screen while the rotary screen, turning about is longitudinal axis, rolls in a continuously revolving path on the circumferential side of the endless belt.
DE 10 2005 006 738 A1 likewise discloses a method in which a topographic pattern on a paper machine clothing is generated by means of a rotary screen.
Combinations including topographic weaving patterns and patterns which are printed thereonto and superimpose the former are also known, for example from EP1242681B1. Here, a fabric which is used in a paper-making machine in order for a pattern to be formed on a tissue paper is described. The fabric comprises a load-bearing layer which defines a first plane, and forming layer which is interwoven with the load-bearing layer and defines a second plane which is spaced apart from the first plane, wherein the upper side has a background texture which is defined by the load-bearing layer and the forming layer. A polymer strand is disposed in a decorative and thread-like pattern on the upper side, the background texture appearing where the pattern formed by the polymer strand does not appear.
The methods mentioned here have various disadvantages. In the rotary screen method it is disadvantageous that no formations of comparatively great length are manufacturable if the size of the screen is to be within manageable limits. The combined fabric and polymer patterns are complex in their manufacture. The freedom of design in terms of the dimensions of the polymer application is not ensured either, but rather is limited by further limiting factors such as the screen thickness and may not be implementable in the desired manner in all fields of application. For example, it is not possible for polymer to be applied in any arbitrary thickness, or height above the screen surface, respectively, since the thickness of the material is correlated to that of the screen.
Moreover the design of the polymer application across the extent of the clothing cannot be varied when the rotary screen printing method is used, despite it being desirable in many cases, for a polymer application which in the peripheral regions is different than in the central part of the clothing to be attached, for example.
Accordingly, it is an object of the invention to mitigate or avoid the disadvantages of the prior art and to state a method for manufacturing an industrial clothing and an industrial clothing which on the one hand is manufacturable such that the fundamental physical properties such as dimensional stability and air permeability are ensured and on the other hand patterns in the desired shape and number may be readily applied to the clothing.
This object in terms of the method is achieved by the claimed method, and in terms of the industrial clothing by the claimed clothing, in each case in conjunction with the generic features.
According to the invention, it is provided that in a first method step 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 is performed. In a second method step at least one polymer material in the form of at least one group of beads is applied 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. This method step is repeated arbitrarily, wherein terminating points of the at least one group of beads are spaced apart from starting points of at least one further group of beads, on account of which regions with a void between the groups on the surface of the planar structure are generated.
On account thereof, beads which are of arbitrary length and number may be manufactured in arbitrary patterns, combinations, and shapes, on the one hand, which beads on the other hand are interrupted at arbitrary spacing and, on account thereof, define regions with a void, so as to, on account thereof, achieve space for further patterns, motifs, logos, etc., which may be readily incorporated into the regions with a void in a further method step or else simultaneously with the beads. Combinations of patterns of an arbitrary variety and having properties of the final product in terms of strength, thickness, air permeability, etc. which are adjustable in an almost unlimited manner may thus be enabled.
According to one advantageous aspect of the invention, all beads have a length which corresponds to at least double the maximum width thereof. The width of the bead may be considered to be the width on the surface of the planar structure, for example.
In one further advantageous embodiment of the method according to the invention, the application of polymer is performed by means of at least one application nozzle. By way of an application by a nozzle, beads which are short as well as of an arbitrary length may be applied without particular technical complexity. The application of polymer is preferably performed by way of a plurality of application nozzles simultaneously. An arbitrary number of application nozzles operated simultaneously are conceivable. In one particularly preferred embodiment the application of polymer is simultaneously performed by means of 5 to 100 application nozzles. The plurality of application nozzles may be disposed in the machine cross direction so as to be beside one another and so as to be fixedly spaced apart. This spacing may be identical for all application nozzles or else be variable. Advantageous spacings between the application nozzles are between 0.5 mm and 20 mm.
In one further advantageous embodiment the application nozzles are actuated individually or in sets. In this way, the application of polymer of the individual application nozzles or sets of application nozzles may be independently activated or deactivated, respectively, and/or regulated. In the context of the invention one set here comprises a plurality of application nozzles, preferably between 2 and 50 application nozzles. One application nozzle here may always be associated with at maximum only one set. The application nozzles of a set here may either be directly adjacent to one another or be mutually spaced apart in a fixed manner, such as, for example, to include every tenth or twentieth nozzle. However, it is also possible for a set to comprise a non-uniform selection of application nozzles.
Actuating the application nozzles in sets offers advantages in economy. In this way, only 10 valves are required for actuating 100 application nozzles which are grouped into 10 sets.
An industrial clothing according to the invention, 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, is an industrial clothing which has been manufactured according to one of the methods according to the invention.
According to one advantageous aspect of the invention, the beads and/or the regions with a void may be configured in the form of patterns or virtual patterns.
The beads are preferably applied along tracks. The individual tracks here run in a uniform manner and beside one another in the machine cross direction. There is a spacing here between two adjacent tracks, which spacing along the profile of the track remains substantially constant. Variations may arise here within the scope of production accuracy. In one particularly preferred embodiment, all spacings between the tracks are of identical size.
The tracks here are to be understood to be like grid lines on which the polymer beads are deposited. Many of the tracks may be completely covered with polymer. Other tracks contain one or more regions with a void between the individual beads. The potential for individual tracks being entirely without an application of polymer may also be provided.
The tracks may particularly preferably run in a straight, undulated, or zigzag manner. However, other variants of a uniform profile are also conceivable.
The tracks may preferably have the full length of the circumference of the industrial clothing. There is also the possibility for the tracks to have an even greater length, up to a multiple of the circumference of the industrial clothing. This is the case with a helically encircling profile of the tracks. In this way, a helical profile of the tracks is conceivable, for example, in that the mounting having the application nozzle or application nozzles, respectively during application is moved in the machine cross direction such that said mounting after one revolution of the industrial clothing is offset in the machine cross direction by its own width.
It is also advantageous for the pattern to be constructed from at least one digital image motif. In the context of this patent application a digital image motif is understood to be a motif which, in an analogous manner to usual digital images, is composed of a finite number of discrete color values. A digital image motif in the context of the invention here is formed by beads and regions with a void. The beads correspond to line-shaped color spots and the regions with a void correspond to white spots. If only one type of beads is used, the digital image motif corresponds to a black and white image. If different types of beads are used, the digital image motif in an analogous manner to a digital image has a plurality of gray scales.
The digital image motif has an extent in the machine running direction and the machine cross direction. Said digital image motif forms the core of the pattern. The pattern per se is created by repeating the at least one image motif. In one preferred embodiment the pattern is created by way of tessellation of the entire surface of the industrial clothing, or at least parts thereof, using the digital image motif.
The digital image motif in one preferred embodiment in the machine cross direction prior to a repeat of the motif commencing extends across at least two beads and/or regions with a void, or across at least two tracks, respectively, in one particularly preferred embodiment the digital image motif embodiment extends across at least three beads and/or regions with a void, or across at least three tracks, respectively, and in a very particularly preferred embodiment the digital image motif embodiment extends across at least five beads and/or regions with a void, or across at least five tracks, respectively.
In one further advantageous embodiment the extent of the digital image motif 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.
According to the two preferred embodiments which have just been described above, the digital image motif in the machine cross direction is thus considerably wider than one individual bead. However, in comparison with the industrial clothing, said digital image motif is still small in the sense that it may be disposed frequently, for example more than 10 times or more than 20 times, across the width of the industrial clothing.
In one further preferred embodiment at least two types of beads are applied on the industrial clothing, which types of beads differ in at least one of the parameters of material, cross-sectional shape, and cross-sectional size. These different types of beads in the fibrous web may lead to various or variously pronounced effects, respectively. This may be utilized for functional or decorative purposes. A digital image motif which is constructed from regions with a void and from two types of beads, for example, may thus be considered to be an image motif with three colors.
The polymer may advantageously be a silicone, a polyurethane, an epoxy resin, or an ester. The mentioned materials in terms of their processability and shelf life are easily manageable and available in bulk quantities.
It may be preferably provided that the polymer is linked to the surface of the clothing in a form-fitting and/or materially integral manner. On account thereof, it is ensured that the beads adhere thereto in a reliable manner, and that the clothing is capable of being used for a long time without material flaking off therefrom.
According to one advantageous aspect of the invention it may be provided that the beads are configured so as to be flush with a surface of the industrial clothing. This is advantageous in particular for forming wires for manufacturing watermarks.
However, according to one alternative variant of a design embodiment it may also be provided that the beads protrude above the surface of the industrial clothing in a direction z. On account thereof, the structuring embossed in the fibrous web becomes more visible.
The height of the beads in the direction z is preferably up to 2 mm. In other advantageous embodiments the height of the beads in the direction z may be up to 5 mm. On account thereof, it is possible for clear and sharply delineated structures which are deeply embossed in the fibrous web to be achieved.
A ratio between the height in the direction z and the width of the beads may preferably be between 0.5:1 to 2:1, preferably be 1:1. Variations therefrom may lead to instability of the beads, damage, and flaking, potentially compromising the quality of the final product.
The invention will be described in the following in an exemplary manner with reference to the figures in which:
Highly schematic exemplary embodiments of patterns 6 which are applied to an industrial clothing which is not illustrated in detail are illustrated in
The patterns 6 are created according to the invention by regularly repeating a digital image motif 5. The image motif 5 in the three figures is in each case composed of beads 1 and regions with a void 3.
The beads 1 in
The tracks 10 in
As shown in
The digital image motif 5 in
The industrial clothing here may be a forming wire, a base fabric of a press felt, a drying wire, a transfer belt, or any further arbitrary clothing. The mentioned clothings may be disposed in various positions in machines for manufacturing a paper, cardboard, or tissue web, or else in machines for manufacturing non-wovens. As has already been mentioned above, various requirements in terms of water permeability, tensile strength, resilience, open volume, etc., are set for the clothing, depending on the position thereof.
The clothings may be configured in a sufficiently known manner in the form of woven or non-woven structures. The planar textile structures which form the clothings are usually manufactured by interweaving warp and weft threads. Clothings which are entirely or partially composed of non-woven components, such as cross-laid structures, knitted fabrics or warp-knitted fabrics, are also known and suitable for application of the measures according to the invention. The planar textile structures may likewise be manufactured by coiling a tape-like material or skeins of threads. Finally, forming clothings by interconnecting helical structures by means of pintles is also known, the latter being usual in particular in the field of drying wires. The clothings may be combined in a known way with further components, such as staple-fiber layers or polymer proportions in the form of films or particles, so as to further model the profile of the properties.
The pattern 6 or else a virtual pattern, which is applied repeatedly or without a specific repeat to at least one surface of the planar textile structure, here is composed of beads 1 from a polymer material, such as silicone, polyurethane, epoxy resin, or esters, for example.
Each of the beads 1 here has a specific length L between a starting point and a terminating point of the respective bead 1. The interruptions 2 lie in each case between terminating points of one or a plurality of beads 1 and starting points of further beads 1. The regions with a void 3 may assume any arbitrary shape, depending on how the mutual spacing of the individual beads 1 is conceived. Patterns 6, virtual patterns, or arbitrary arrangements of regions with a void 3 may be generated.
In a further step of the manufacturing method these regions with a void 3 may then be provided with a further polymer pattern which may be a personalized motif or a logo, for example.
The pattern 6 here may be selected for aesthetic and/or practical considerations, the latter influencing the physical properties of the fibrous web, for example.
The topography of the beads 1 may vary depending on the respective field of application of the clothing as well as on the thickness and the grammage of the product. The beads 1 may lie in the plane of the clothing surface or protrude above the latter by a certain height in the direction z of up to 5 mm. The width of the beads 1 here depends on the height in the direction z. The ratio of height to width will typically be in a range of approx. 0.5:1.0 to 2:1. A ratio close to 1:1 is currently preferable, so as to ensure an optimal shape of the beads 1. The spacings between the individual beads 1 are preferably at least of the same size as the width of said beads 1.
The polymer adheres to the surface of the clothing by way of a combination of form-fit and material integrity. Form-fitting here is obtained by way of the threads of the planar textile structure by encasing said threads with a polymer. The material combination of clothing and polymer may optionally also form a chemical bond and, on account thereof, enable material integration. Pre-treatment of the clothing for the purpose of improving adhesion of the polymer to the clothing, for example by way of plasma activation, is likewise possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102013206278.8 | Apr 2013 | DE | national |
This application is a divisional of patent application Ser. No. 14/784,094, filed Oct. 13, 2015; which was a § 371 national stage filing of international application No. PCT/EP2014/057131, filed Apr. 9, 2014, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. DE 10 2013 206 278.8, filed Apr. 10, 2013; the prior applications are herewith incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14784094 | Oct 2015 | US |
| Child | 15948365 | US |
