Cloth, and method for manufacturing a cloth

Abstract

A cloth comprising a woven wire cloth covering an extended cloth area wherein said wire cloth has a uniform, low-reflective surface in that it consists of oxidized filaments, and a method for manufacturing a cloth.

Description

The present invention relates to a low-reflective cloth and a method for manufacturing such a cloth. Low-reflective cloth types have been known in the prior art where wire cloth is treated by electroplating to suitably manipulate and configure the surface. A galvanic coating may be applied so as to reduce the reflectivity characteristics of the cloth.

One drawback of such electroplated cloths is that the galvanic coating is applied only in open, accessible places. The contact points of warp and weft wires will not be plated.

It is therefore the object of the invention to provide another cloth and another method for manufacturing a cloth which has overall a substantially uniform and low-reflective surface.

This object is achieved according to the invention by a cloth having the features of claim 1. The inventive method is the subject matter of claim 17. Preferred specific embodiments and configurations are the objects of the subclaims.

The cloth according to the invention comprises a woven wire cloth covering an extended cloth area. The wire cloth has a uniform, low-reflective surface in that at least part of it consists of oxidized filaments.

The invention has numerous advantages. It is a great advantage that the cloth filaments are oxidized since this allows a uniform, low-reflective surface. Surface conditions are equal on the filament surfaces as well as at and near the individual contact points of the warp with the weft filaments. This will make the reflection characteristics of the wire cloth generally homogeneous and uniform. Other structures may show locally different characteristics in the vicinity of the individual filament contact points.

It is another very great advantage that the cloth is not limited to specific dimensions. For example for a cloth being surface-coated by electroplating the cloth section sizes are limited by the size of the electroplating tanks. The invention, however, employs surface-treated filaments for manufacturing the cloth such that the material can be manufactured in rolls.

It is another advantage of the invention that contamination of or damage to the material during the electroplating process is prevented. The electroplating process requires special electroplating tanks. Since for reasons of cost-effectiveness most electroplating tanks are used for electroplating a variety of objects, there is the risk that fine wire cloths are contaminated through particles present in the electroplating solution. This requires extensive cloth cleaning after electroplating. Contamination may even make a cloth entirely useless. These conceivable drawbacks are avoided by the invention.

The wire cloth filaments consist substantially of metal and they are preferably wires. Preferably said filaments or wires are monofilaments. Specific embodiments may provide that at least some filaments consist at least partly of multifilaments. Said multifilaments may comprise twisted yarns and/or metal fiber yarns and/or strings and/or strands or be configured as such.

More specific embodiments of the invention provide for all of the filaments to consist in particular at least partially and preferably substantially of steel, in particular stainless steel. The filaments preferably consist of stainless steel, so-called high-quality steel. The filaments may preferably consist of acid-resisting and/or alkali-resisting steel.

High-quality steel filaments are very advantageous since they withstand high stresses and allow permanent use even in difficult conditions and with aggressive media.

In preferred specific embodiments at least some, in particular substantially all of the wire cloth filaments have a diameter of typically smaller than 100 μm. The typical diameters of the warp filaments and/or the weft filaments are in particular smaller than 100 μm. It is conceivable to use warp filaments and weft filaments of different diameters.

Preferred more specific embodiments provide in particular for the cloth to be employed as a screen printing cloth. In preferred specific embodiments of the invention the typical cloth wire filament diameter is in particular smaller than 60 μm. The typical diameter may be smaller than 50 μm, thus being approximately 30 μm or 25 μm or even as small as 18 μm. In particular with screen printing cloths this will allow very fine screen textures. This is often desired for printing electrical circuits since fine or minuscule conductors must be manufactured.

For configurations with fine filaments it is preferred to weave a high number of meshes per length unit. Thus these weaves show a number of meshes per inch of length, or within 25.4 mm, of at least 100. It is particularly preferred to have a number of meshes within one inch of cloth length of 150 or 200 or higher. For example with screen printing cloths the number of meshes may be 300 or higher.

Other embodiments provide a number of meshes per inch of length at least in one direction greater than or equal to 40.

It is preferred to employ or configure such a cloth as a protecting cloth. The number of meshes per inch of length in such applications is in particular smaller than 150 and in particular smaller than 100. Preferred number of meshes for protecting cloths per inch of cloth are approx. 40 to approx. 80.

In other embodiments at least some of the wire cloth filaments have a diameter of typically larger than 500 μm. A typical diameter may in particular be in the range of 1 or 2 millimeters or larger.

In these cases the mesh number or the number of meshes within one inch of length is preferably at least in one direction smaller than 5 and it may be equal to or smaller than 1.

In such embodiments the cloth according to the invention may in particular be employed as a wire cloth for architecture. The dull effect of the cloth can also be obtained in processing the wires in that for drawing some or all of the wires a dry drawing agent is used so as to obtain a low-reflective surface.

In all of the embodiments and more specific embodiments of the invention, filaments having a dark surface are preferred. The color brown is in particular preferred. Other colors are also conceivable such as blue or red or golden hues. This depends on the manufacturing and treatment conditions.

In preferred embodiments at least some of the filaments are synthetic. The cloth can then entirely be a hybrid cloth of synthetic and metal threads. The synthetic fibers may consist of monofilaments or multifilaments.

The synthetic fibers may be woven into the cloth in addition to the metal threads. They then serve in particular for strengthening or reinforcing the cloth. The synthetic fibers may be arranged to be evenly distributed over the cloth surface or over individual cloth areas.

It is also conceivable to provide an overall or in particular locally uneven distribution of the synthetic fibers over the cloth surface. For example—for cloth or sections to be used for example as screen printing cloth—strengthening may occur by framing the print area with synthetic fibers.

The wire cloth is in particular configured and structured so as to be suitable to be clamped in with a clamping force of at least 20 N per cm cloth edge. The wire cloth is in particular configured to be used at clamping forces of 25 N/cm or 30 N/cm or higher. With screen printing cloths in particular the wire cloth is mounted on a frame and then tensioned at the desired clamping force. Wire cloth furnishes among other things the advantage of higher stressability than woven synthetic fibers. Moreover, wire cloth does not require re-tensioning but permanently retains the fixed clamping force.

This is an advantage in particular for screen printing cloths since the substantially stable clamping force allows fine screen printing where the printing precision does not deteriorate with increasing age of the screen printing cloth. Therefore such a screen printing cloth is in particular suited for printing circuits.

In this respect the invention also relates to screen printing cloth and to using a cloth as a screen printing cloth. The screen printing cloth according to the invention comprises a woven wire cloth covering an extended cloth area having a substantially uniform and low-reflective surface. This is achieved in that the cloth consists of oxidized filaments at least in part.

The invention also relates to protecting cloth and to using a cloth as a protecting cloth. The protecting cloth according to the invention comprises a woven wire cloth covering an extended cloth area having a substantially uniform and low-reflective surface. This is achieved in that the cloth consists of oxidized filaments at least in part.

The protecting cloth serves to shield from radiation emitting in particular from electrical devices. The protecting cloth may be configured in accordance with one of the embodiments described above. The protecting cloth is in particular provided to be employed with electrical or electronic devices or X-ray apparatus or other apparatus emitting harmful or interfering radiation.

With medical electrical apparatus for example it must be guaranteed that the electromagnetic radiation generated will not affect other medical equipment as stray radiation. For this purpose one may employ a protecting cloth applied inside the apparatus and possibly mounted in front of visible areas. The mounted protecting cloth must not hinder the user's view and therefore a low-reflective cloth is used. The cloth according to the invention is suitable for this purpose of reliably protecting from radiation while affecting the visual impression to a minimal extent.

Furthermore the invention also relates to wire cloth for architecture and to using a cloth as a wire cloth for architecture. The wire cloth for architecture according to the invention in turn comprises a woven wire cloth covering an extended cloth area having a substantially uniform and low-reflective surface. This is achieved in that the cloth consists of oxidized filaments at least in part.

The invention also relates to a method for manufacturing a cloth with a woven wire cloth covering an extended cloth area wherein first at least part of the filaments or wires for manufacturing said wire cloth are purposely oxidized and only thereafter woven.

The inventive method also offers considerable advantages. Pretreatment of the filaments or wires of the wire cloth allows to manufacture a uniform, low-reflective cloth. The cloth sizes are not limited to specific tank dimensions but they can be chosen as desired since the cloth can be manufactured as a continuous material.

The treatment of the wires allows a homogeneous surface configuration of the individual filaments so as to guarantee a uniform, low-reflective wire cloth surface even in tight wire cloth areas.

Preferred more specific embodiments of the method according to the invention provide for the filaments or wires to be annealed. The wires are in particular conveyed through a furnace for heating the filaments. To this end, a volume flow of a gas mixture is supplied in the furnace or at or in front of the furnace.

The gas mixture preferably consists at least of at least one inert gas and furthermore comprises gaseous water. The gaseous water serves in particular as an oxidizer for the wire surfaces.

In order to enrich the inert gas, which may include a number of inert gas components, with water vapor, at least part of the volume flow of the inert gas is preferably passed through a container with a water reservoir. Within said container, vaporous water is added to the volume flow. This process may be enhanced by atomizing liquid water. Or else the inert gas may be passed through a water bath where it absorbs water vapor.

The preferred inert gas employed is nitrogen. Argon or another inert gas may also be used.

Inside the furnace a measure for the humidity of the gas mixture is preferably determined by means of a humidity measuring means. Preferably the humidity, i.e. the water vapor content, of the gas mixture is controlled. This occurs preferably by using the humidity measuring means signal and in dependence thereon adjusting the water vapor supply.

The water vapor content may in particular be influenced through the liquid water temperature in the water reservoir. The temperature in the water reservoir is therefore preferably controlled.

It is furthermore advantageous to control the temperature and/or the volume flow and/or the ambient pressure of the inert gas or the gas mixture.

It is furthermore preferred to control the conveying speed of the wires through the furnace.

Furthermore the furnace temperature is preferably controlled. Preferred embodiments may provide a furnace temperature of 1100° C. In a preferred embodiment the wires may for example be heated to values of approx. 600° C., 800° C. or 1000° C. or higher.

After heat treatment the wires or filaments are preferably coated with an agent to allow better handling during weaving. After weaving the cloth is preferably cleaned. This is for removing, among other things, any remaining coating agent residue.

Further features, properties and advantages of the present invention will be understood from the following description of embodiments in conjunction with the attached drawing.

It shows in:

FIG. 1 a schematic view of a cloth according to the invention.

FIG. 1 is a highly schematic illustration of a first embodiment of an inventive cloth.

The cloth 1 according to the invention comprises a wire cloth 2. The cloth can be mounted on a—not shown—frame. FIG. 1 illustrates exemplarily a number of warp wires 11 to 18 and a number of weft wires 21 to 26 of the wire cloth 2. These filaments or wires 11 to 18 and 21 to 26 are high-quality steel.

The cloth 1 represented in FIG. 1 is a plain weave. In other embodiments, other types of weave may be used. Aside from twilled or satin twilled weave, any other types of weave may be used in the cloth according to the invention. In particular for use as a wire cloth for architecture for covering building facades, inner and outer walls, or open air passages or other structures, the cloth according to the invention may have other types of weave to exhibit the desired strength properties and to achieve an attractive optical effect.

The surface 3 of the wires was oxidized by the method according to the invention before weaving. This occurs by annealing the wires in a furnace. The conveying speed of the wires is adjusted such that the wires reach the required temperature. To manufacture low-reflective wires from the bright high-quality steel wires, an inert gas containing a defined proportion of water is introduced into the furnace.

The volume flow of the gas mixture is adjusted at a defined value.

With the high temperatures of up to 1100° C. or higher present in the furnace the water vapor acts as an oxidizer, scaling the wire surfaces which thus lose their shine and change their color.

The furnace temperature may be employed to influence the surface quality of the wires leaving the furnace. The wires reach temperatures of e.g. approx. 980° C. to 1000° C. The temperatures may be lower and in particular considerably lower. The adjusted temperature depends on the desired results, e.g. the surface color is thus related to the temperature. The color hue may be set in dependence on a number of parameters to obtain e.g. blue, brown, golden or red hues.

The temperature and the other conditions will result in a corresponding structure of the surface 3 of the wires.

For low-reflective screen printing cloth, a brown color will as a rule be set. The same applies to protecting cloth, the so-called shielding cloth, for shielding radiation.

The water vapor is only allowed to enter in low concentrations; the water vapor molecule concentration may thus be a few ppm (parts per million) or a few tens of ppm. The inert gas employed may e.g. be nitrogen enriched with water vapor. Enriching may for example occur in normal ambient temperatures such that only a little water vapor is absorbed. A small portion of water vapor is already sufficient to reliably and reproducibly effect scaling.

The water proportion is controllable. A humidity sensor may be provided in the supply line for the gas mixture in front of the furnace or even in the gas mixing device and dependent on the result the inert gas temperature or pressure can be adjusted.

Since the wires—in particular for screen printing cloth—may be extremely fine, at diameters 5 in the region of e.g. approx. 100 μm down to approx. 20 μm, supplying pure oxygen would oxidize the entire wire. The wire could no longer be woven then. It is therefore imperative to treat only the surface 3 of the wires to guarantee further processability and the function. The physical properties essential for weaving are substantially not affected in the negative.

A number of meshes 6 per length unit is selected depending on the application. As a rule, the number of meshes is indicated per inch of length (mesh count). For screen printing cloth for printing circuits the mesh count can be increased up to 250 and even above 300. With a mesh count of 254, there are as many as 10 wires per millimeter. If the wires are not intended to be tightly packed, given a mesh count of 254 the wire diameter should be smaller than 100 μm. A typical wire diameter is e.g. 30 μm.

The free areas 7 between the wires serve to apply material to the ground in a screen printing process.

The wire clearance 4 between the wires may be in the range of the wire diameter 5 or it may be a multiple thereof.

With protecting or shielding cloth for shielding radiation e.g. of monitors, the mesh count will as a rule be smaller, being between approx. 40 and 80.

Claims

1. A cloth, comprising a woven wire cloth covering an extended cloth area, said wire cloth including oxidized filaments to provide a uniform, low-reflective surface.

2. The cloth of claim 1, wherein the filaments are made of high-quality steel.

3. The cloth of claim 1, wherein at least some of the filaments have a diameter of smaller than 100 μm.

4. The cloth of claim 1, wherein the wire cloth has a number of meshes per one inch of length of greater than or equal to 40 at least in one direction.

5. The cloth of claim 4, wherein the number of meshes per one inch of length is greater than 100.

6. The cloth of claim 1, wherein at least some of the filaments have a diameter of larger than 500 μm.

7. The cloth of claim 1, wherein the wire cloth has a number of meshes per one inch of length of smaller than 5 at least in one direction.

8. The cloth of claim 1, wherein the filaments have a dark surface.

9. The cloth of claim 1, wherein the wire cloth is configured for clamping at a clamping force of at least 20 N per cm of cloth edge.

10. The cloth of claim 1, wherein at least some of the filaments are synthetic.

11. The cloth of claim 10, wherein the synthetic filaments are evenly distributed in the wire cloth.

12. The cloth of claim 10, wherein the synthetic filaments are unevenly distributed in the wire cloth.

13. The cloth of claim 1, for use as a screen printing cloth.

14. The cloth of claim 13, for printing circuits.

15. The cloth of claim 1, for use as a protecting cloth.

16. The cloth of claim 1, for use as a wire cloth for architecture.

17. A method for manufacturing a cloth with a woven wire cloth covering an extended cloth area, comprising the following sequence of steps:

oxidizing a desired number of wires of a plurality of wires and

weaving the plurality of wires to produce a wire cloth.

18. The method of claim 17, wherein the oxidizing step includes the step of subjecting the wires to an annealing process by passing the wires through a furnace in the presence of a volume flow of a gas mixture.

19. The method claim 18 wherein the gas mixture includes inert gas and gaseous water.

20. The method of claim 18, wherein at least part of the volume flow is passed through a water reservoir.

21. The method of claim 18, further comprising the step of measuring a humidity of the gas mixture.

22. The method of claim 18, further comprising the step of controlling at least one parameter selected from the group consisting of temperature, volume flow, and ambient pressure of the gas mixture.

23. The method of claim 20, further comprising the step of controlling a temperature of the water reservoir.

24. The method of claim 17, wherein the oxidizing step includes the step of controlling a conveying speed of the wires.