Patent Application
20160053436
The invention proceeds from a clothing for a machine for manufacturing a web material, such as, for example, paper, cardboard, tissue, film, a non-woven product, or a composite product, according to the preamble of claim 1.
A clothing of this type which may be employed as a forming wire in a paper machine, for example, is known from EP 1 690 981 A1. In this known paper machine clothing, a pattern from polymer material is applied in a rotary printing method by means of a rotary screen to a carrier structure which is configured as a woven fabric, for example. The pattern in substantially any arbitrary design may be applied to the woven carrier fabric, so as to generate on one side of the paper machine clothing thus manufactured a surface structure which during paper manufacturing is reproduced having a corresponding topography in the manufactured paper.
A method for applying a pattern to a paper machine clothing in which a polymer material in an extrusion operation is dispensed from an extrusion head and thus applied to the surface of a carrier structure which may be of a woven-fabric type, for example, is known from EP 1 690 982 A1. The extrusion head may be moved arbitrarily above the surface of the carrier structure.
Furthermore, a clothing for a paper machine, in which a basic structure is printed multiple times with a polymer structure, wherein a first polymer layer has a grid-type structure and a second polymer layer largely occupies the clearances in the grid-type first layer and thereby partially superimposes the first layer, is known from US2008/0991701A, for example. The manufacture of structures of this type here is achieved by applying a polymer to the entire area of the surface of the basic structure, masking, radiating with light of a specific wavelength, and, on account thereof, curing the parts which are not masked, and subsequently removing the non-cured polymer proportions.
A woven paper machine fabric for perfused air drying, which has a three-dimensional woven pattern which has a structure which has height differences in the Z-direction of 0.2 mm or more, is known from U.S. Pat. No. 7,624,765B. The clothing has decorative elements which are surrounded by accentuation areas, the decorative elements being surrounded by the three-dimensional woven pattern of the clothing and having a height lesser than the structure of the woven pattern. The woven pattern represents a structured background surface which is the prevailing contact area of the clothing with the paper web.
It is disadvantageous in the known clothings that the patterns which are generatable in this manner indeed may be fit for their decorative purpose, for example by offering an aesthetic impression in the finished product, for example, but that the physical properties of the clothing and of the product are incapable of being sufficiently influenced by only one pattern component. It is thus desirable for variously shaped patterns to be manufactured, for example, which fulfill different functions. In many cases, combinations of patterns may indeed be generated by way of the above-mentioned methods, the patterns however being all manufactured in the same way and the applied patterns thus having identical cross-sectional shapes in all components, on account of the application method which is always identical. It is thus impossible for individual pattern components having different cross sections to be configured, such that it is likewise impossible for different pattern components for various tasks to be selectively configured in the clothing.
If and when various patterns are generated as a result of a specific design of the basic structure by way of a woven pattern and subsequent printing using a polymer, the method is characterized by high complexity and thus also high costs.
It is thus an object of the present invention to state clothing which is readily manufacturable and which has pattern components that permit the physical and aesthetic properties of the clothing to be selectively influenced.
The object is achieved by the characterizing features of claim 1 in combination with the generic features.
It is provided here according to the invention that a cross-sectional shape of a first pattern component and a cross-sectional shape of at least one further pattern component are different from one another. On account thereof, aesthetic motifs, for example, may be highlighted in an intense and sharp manner and may be surrounded by a background which has been drawn so as to be softer and which is less prominent. Coarse patterns for physically modeling de-watering parameters may be combined with fine patterns for designing a visually and haptically appealing surface of the final product. The physical and aesthetic properties of the individual pattern components may thus be selectively modified and adjusted in a mutually independent manner, so as to emboss patterns of variable intensity in the finished product and so as to thus also model the physical and aesthetic properties of the finished product. It is furthermore possible for the properties of the clothing in terms of their behavior during manufacturing of the fibrous web to be modeled and on account thereof for dynamic processes to be supported.
Further advantageous aspects and refinements of the invention are derived from the dependent claims.
According to one preferred embodiment of the invention it may be provided that the cross-sectional shape of the pattern components is angular, in particular rectangular or square, or rounded, in particular at least segment-shaped or oval. On account thereof, structures which are optionally less or more intensely prominent and which facilitate in influencing the aesthetic and physical properties may be generated in the fibrous web.
An overall shape of the pattern components may be selected from drops, beads, lines, grid structures, contiguous or non-contiguous elements.
It may be advantageously provided that the pattern components are in mutual contact, mutually intersect, or are mutually isolated, depending on the requirement profile.
It may be advantageously provided that the first pattern component is composed of a first material, and the at least one second pattern component is composed of a second material, wherein the first and the second material may be identical or different from one another. If and when various requirements are set for the pattern components, it may be advantageous for one of the materials to be harder or softer, more resistant to abrasion, smoother or coarser than the other material.
The material of the pattern components may preferably contain or be composed of: amide, ester, silicone, urethane.
According to preferred aspects of the invention, sizing of the pattern components may be at a height of 0 to 10 mm above the basic structure, at a width of 0.1 to 10 mm, and at a length of 0.1 mm to indefinite.
Sizing of the pattern components may be particularly preferably identical or variable. There are thus no limits applicable to the diversity of patterns and the precise adjustment of the desired physical parameters, in particular the desired dynamic parameters, of the clothing and to the arbitrary design of the final product.
Application of the pattern components to the basic structure may be performed unilaterally or bilaterally, depending on intended use. A combination with further components may likewise be performed, for example in order to manufacture a pressing felt once printing of the basic structure has been completed.
Application of the pattern components may be readily performed by application methods which are known per se, such as extruding, roller coating, spraying, squeegee coating, or screen printing.
According to advantageous design embodiments of the invention, the basic structure may be present as a woven fabric, a cross-laid structure, a warp-knitted fabric, a helical screen, a helically coiled structure, or as films, as a joinable planar structure, or as an endless belt.
The invention will be described in more detail in the following, by way of example, with reference to the figures and without limiting the general scope thereof. In the figures:
A plan view of a clothing 1, which is in particular suitable for use in a machine for manufacturing a fibrous web, such as a paper, cardboard, tissue, or film machine, and in a machine for manufacturing a non-woven product or a composite product, is shown in a very schematic view in
A plurality of clothings 1 which depending on their position fulfill various tasks are currently provided in such a machine. For instance, a clothing 1 in the forming section serves as a forming wire and thus for initially de-watering the fibrous suspension which has been sprayed onto the forming wire or has been injected between two forming wires in a double-wire former, and for orienting the fibers in the nascent fibrous web. Clothings 1 are provided as pressing felts for further de-watering in the downstream pressing section, which clothings 1 should have a high absorptive capacity for water, good resilience, smooth contact surfaces to the fibrous web, and a low tendency toward rewetting. The clothing 1 in the drying section is often configured as a drying wire in the shape of a helical structure and, on account thereof, is distinguished by a high resistance to temperature at high permeability to air.
Clothings 1 also often serve for incorporating a decorative pattern in the fibrous web, this representing the current standard in the field of hygiene tissues in particular. The patterns here have both aesthetic features as well as features which influence the properties of the paper web, such as the grip of the surface, the thickness of the layers, etc.
The individual features here are often conceived such that a decorative and often also personalized pattern is desirable, but that the latter is not able to fulfill the requirements which are set for the physical properties of the fibrous web. It has thus been necessary to date for the clothing 1 to be subjected to at least two separate operational steps in order for at least two patterns to be manufactured in or on the respective clothing. For example, as mentioned at the outset, is possible for a three-dimensional structure to be generated when manufacturing a basic structure 2 of the clothing 1, and for this structure to be then superimposed by a pattern which is printed on at least one surface of the clothing 1, for example. The structure of the basic structure 2 here may be manufactured by established weaving patterns, while the printed pattern is applied by a rotary screen printing method, for example. Weaving of such basic structures 2 is in particular a very complex process which moreover is very limited in terms of its diversity of patterns. Due to the nature of weaving, in each case only the machine direction, the machine cross direction, and diagonals may be incorporated in the pattern; an arbitrary selection of patterns and a selective intervention in the property profile of the clothing 1 are thus not possible.
Therefore, it is proposed according to the invention to provide the basic structure 2 with at least two pattern components 3, 4, which have different cross-sectional shapes and thus generate different effects in terms of the aesthetic appearance and the physical property profile of both the clothing 1 as well as of the finished product.
Arbitrary planar structures, such as woven fabrics, cross-laid fabrics, warp-knitted fabrics, helical wires, helically coiled structures, and also films are employable here as the basic structure 2. The basic structure 2 may be present in a flat form, having the potential for joining, or as an endless belt. Permeability to liquids and gasses is to be selected with a view to the application purpose of the clothing 1. The basic structure 2 may subsequently be combined with additional components which are not illustrated in more detail in the figures, such as layers of staple fibers, films, non-woven reinforcement structures, or coatings on one or both sides, as well as other components, for example impregnations, which adapt the clothing 2 to the prevailing conditions.
A plurality of at least two pattern components 3, 4 are applied to the basic structure 2 by arbitrary application methods such as extruding (in the form of drops, lines, films, etc.), coating (by rollers, spraying, or squeegee coating), or screen printing. Application here may be performed on one or on both sides of the basic structure 2.
The pattern components 3, 4 here may be composed of an identical material or of different materials. Individual types of polymers or else a plurality of specifically selected groups/classes of polymers may be provided. The selection of the materials may be performed both microscopically as well as macroscopically, depending on the requirements in terms of stability, sizing, smoothness, coefficient of friction, elasticity, open surface, open volume, permeability to gas and liquid, or conveyability of gas and liquid, respectively, etc., of the individual pattern components 3, 4.
Examples of suitable materials here include amides, esters, silicones, and urethanes, and arbitrary combinations thereof.
As can be seen from
Generating these variously shaped pattern components 3, 4 may be performed, for example, by extruding a comparatively hard and rapidly curing polymer out of a suitably shaped nozzle for the first pattern component 3, and by applying a rather liquid polymer which thus bleeds more intensely in a drop-wise manner out of a differently shaped nozzle for the second pattern component 4.
In the exemplary embodiment illustrated, a fine and richly detailed background structure in the finished product is generated by the second pattern component 4 by means of a low height above the basic structure and soft and rounded shapes. The background structure of the product here is generated by mechanical influences, such as hydraulic pressure and the distribution of the fibers in the fibrous suspension, and later in the finished product.
By contrast, the first pattern component 3 stands proud of the basic structure 2 to a greater height and, on account thereof, may impart a higher topography associated with higher functionality. Advantages derived therefrom may be seen in particular in optimizing the drainage of liquid or the conveyance of liquid, respectively, during the dynamic formation of the final product. This higher and coarser structure may conversely serve as a reinforcement of the basic structure 2. The basic structure 2 thus supports the pattern component 3, while the latter makes available to the clothing 1 a higher volume for liquid absorption. The latter is an important parameter when judging the dynamic properties of the clothing 1. Throughput rates for masses and gasses are good examples of the dynamic state which is capable of being influenced here, such as can be seen in the drying process by way of migration of liquid or evaporation, for example.
Further advantages of the more intense topography of the first pattern component 3 are to be seen in the product having the ability to be three-dimensional. Depending on the specific application of the clothing 1, in particular on the point in time at which embossing into the fibrous web takes place during the manufacturing thereof, the ability to be three-dimensional may be semi-permanent (similar to an embossing) or durable and thus be a feature of the finished fibrous web. The latter may be performed in particular during the final finishing steps, such as drying or curing of the final product.
A further advantageous aspect of the high topography of the first pattern component 3 is to be seen in facilitating drawing-in of the clothing 1 into the fibrous web machine. On account of there being fewer bearing points present, and on account of the coefficient of friction of the bearing points being able to be reduced due to suitable selection of the material which forms the pattern component 3, it is easier and safer for the personnel to draw-in the clothing 1 and to dismount the latter.
With reference to the dimensions of the pattern components 3, 4, reference is made to current orders of magnitude which may be in the range of 0 to 10 mm in terms of height above the clothing 1, of 0.1 to 10 mm in width and of arbitrary length for the first pattern component 3 in the illustrated exemplary embodiment.
The rotund shapes of the second pattern component 4 in the exemplary embodiment may have similar dimensions with an identical or similar extent in all spatial directions.
It is conceivable and possible for further pattern components which are not illustrated in more detail and have further cross-sectional shapes which are identical or different from one another and are from the same or different polymers, having the same or different sizes, to be added to the two pattern components 3, 4 which are illustrated in the exemplary embodiment.
The invention is not limited to the illustrated exemplary embodiments. Combinations of the features are particularly possible and conceivable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 206 265.6 | Apr 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/057130 | 4/9/2014 | WO | 00 |
