Title of Invention

A PROCESS FOR PRODUCING HYDROPHILIZED TEXTILE SHEETLIKE STRUCTURES

Abstract A process for producing hydrophilicized textile sheetlike structures The present invention relates to a process for producing hydrophilicized textile sheetlike structures containing synthetic fibres which have a high intitial wettability comprising the steps of: a. forming a textlie sheetlike structure by a textile sheet- forming technique in a conventional manner, b. providing a space, c. transporting the textile sheetlike structure through the space in which the barrier discharge burns, so that the textile sheet-like structure is exposed to the barrier discharge, characterized in that, the corona generator consists essentially of a first resonant circuit, a switch and a second resonant circuit which has an associated high-voltage transformer, the first resonant circuit is a series-tuned circuit which has an inductor and a capacitor which is connected via a switch, a diode and an induce to the primary winding of a high- voltage transformer, and wherein the inductance of the inductor in the flfst resonant circuit and the switching criterion, which is derived from the voltage across the capacitor, for the switch the second resonant circuit are selected such that the clock frequency of the voltage pulse (which occur in the generator) on the primary winding is less than the eigen frequency of the damped oscillation of the second resonant' circuit.
Full Text

Applicant: Carl Freudenberg KG, 69465 Weinheim
Plasma-treated textile sheetlike structures, production
thereof and use thereof
Description
The present invention relates to plasma-treated textile sheetlike structures, especially nonwoven fabrics, having a durable hydrophilicization, their production and their use as separators for electrochemical cells, especially as separators for rechargeable alkaline batteries.
Electrochemical energy stores, such as alkaline batteries or cells, have to be equipped with separators which keep the two differently charged electrodes apart in the energy store and thus prevent internal short circuiting. Separator materials have to meet a whole series of requirements, which can be summarized as follows:
1. Stability to electrolyte, 2 . Stability to oxidation,
3. High mechanical stability,
4. Low weight and thickness variability,
5. Low ion passage resistance,
6. High electron passage resistance,
7. Retainability for solid particles detached from electrodes,
8. Immediate spontaneous wettability by electrolyte (generally within times of less' than 10 s);

9, Permanent wettability by electrolyte, and
10. High storage capacity for electrolytic fluid.
Textile sheetlike structures, especially nonwoven fabrics formed from synthetic fibres, are inherently very useful as separator materials because of high stability to electrolytic fluids and also high flexibility.
However, the corresponding separator materials have various advantages and disadvantages, depending on the polymer used to produce the separator.
For instance, separators formed from polyolefins are very resistant to chemical attack due to strongly alkaline electrolytes and to oxidation in the chemical environment of the cells, but wettability by the alkaline electrolyte is poor. Polyamide, by contrast, is always sufficiently wettable, but its hydrolysis stability with regard to alkaline electrolytes is insufficient at relatively high temperatures in particular.
Nonwoven fabrics formed from a very wide range of materials have already been proposed for use as separator materials, A very wide range of treatment methods for ameliorating or avoiding disadvantages of individual separator materials are also already known.
For instance, DE-A-2,164,901, DE-A-1,142,924, DE-A-2,203,167 and DE-A-2,438,531 describe separators for alkaline batteries that are composed of polyamide and/or polyolefins.
There are in many cases serious disadvantages as a result of using hydrophobic fibres, since hydrophobic fibres do not have the requisite electrolyte take-up ability and the requisite retainability for electrolytic fluid.

Various processes have already been proposed for enhancing the wettability of polyolefin fibres.
For instance, separator materials have been rendered hydrophilic as described for example in US-A-3,947,537, DE-A-2,542,089 or DE-A-2,542,064. The danger with this approach is that the electrolytic fluid is contaminated by the customarily used wetting agents or the hydrophilic substances which are in some instances added directly to the hydrophobic polymer, and so the use life of the energy store is curtailed. Nonwoven fabrics which have been rendered hydrophilic in this way therefore have only limited usefulness as battery separators in that the sensitive system of the electrochemical energy store is disrupted by the introduction of additional chemicals.
It is therefore preferable to engineer separators only from accurately defined fibrous materials of construction and to use only such hydrophilic additives as cause no disruption in energy store operation,
Polyolefin fibres can also be rendered hydrophilic by being fluorinated, as described for example in JP-A-2/276, 154 and DE-A-195 23 231. The electrolyte take-up capacity and permanent wettability of thus treated separators with the electrolyte solution does indeed meet the stated requirements, yet these fluorinated nonwoven fabrics have only limited usefulness as battery separators because there is no spontaneous wetting with electrolyte fluid. This poor initial wettability leads to disruptions in cell production, since the electrolyte metered in is insufficiently quickly absorbed by the separator and disbursed in the interior of the cell, so that subsequently added electrolyte is forced to overflow and thus contaminate the product.

Permanent wetting with high initial wetting without decrease in hydrophilicity due to storage under ambient conditions can be achieved through wet-chemical processes. EP-A-593,612 discloses a process for surface modification of polyolefins by wet-chemical grafting with a vinyl monomer. The textile sheetlike structures treated comprise polyolefin fibres whose surface has been grafted with specific vinyl monomers and which have acquired an ion exchanger capacity as a result of this modification.
EP-A-316,916 discloses sulphonation with oleum as a way of achieving surface modification of separators formed from polyolefins. Wet-chemical surface enhancement processes involve emissions of solvent vapours and/or emissions to water and so are problematical with regard to occupational hygiene and ecological requirements. The costs of these processes are relatively high because of the high energy and time requirements of drying steps.
Similarly, plasma-based processes for hydrophilicizing textile sheetlike structures have already been proposed.
Durable hydrophilicization without use of chemicals has hitherto only been known in low-pressure plasma. Corresponding processes, which are operated at reduced pressure, are described in DE-A-3,116,738, DE-A-100 37 048 and EP-A-999,602. Nothing is known about the long-term stability of the hydrophilicity of the treated materials.
The textile industry is increasingly favouring plasma-based and atmospheric processes (such as the corona discharge process for example) since they, unlike the classic low-pressure plasma process, dispense with costly and inconvenient vacuum technology. This reduced not only capital costs but also operating costs.

JP-A-2 001/068,087, JP-A-05/295,662, JP-A-01/072,459, JP-A-08/311,7 65, JP-A-20007208,124, JP-A-2000/215,874, EP-A-937,811 and DE-A-197 31 562 describe processes for treating textile sheetlike structures or porous materials by electrical discharge under atmospheric pressure, although in each case the discharge is sparked in the presence of chemical process gas, for example SO2, NO2/ acetone, fluorinated hydrocarbon, azo compounds or peroxides.
In JP-A-11/354,093, a corona discharge precedes or follows an impregnation with a surfactant to achieve durable and fast wettability of battery separators.
JP-A-057006,760, JP-A-12 7123,814 and JP-A-117354,093 utilize a corona discharge before or after a classic wet-chemical sulphonation or after a treatment with aqueous potassium hydroxide solution to achieve durable and fast wettability of battery separators.
DE-A-4,235,766 describes the treatment of materials by means of a corona discharge.
Further processes and apparatuses for plasma treatment of substrates are known from DE-A-41 00 787, WO-A-00710,7 03, WO-A-94 72 8,568, EP-A-937,811 and DE-A-197 31 562. The latter reference describes using a barrier discharge with air as a working gas.
DE-A-100 17 680 likewise proposes treating a textile fabric web, on at least one surface thereof, with electrical charge carriers. Again, a plasma barrier discharge is utilized.
It has now been found that textile sheetlike structures treated with a plasma generated by a specific corona generator acquire a desired combination of properties,*

forming products which are particularly useful as separators.
The inventive products are notable for a high initial wettability and for durable hydrophilicity.
Taking the above-described prior art as its starting point, the present invention provides hydrophilic textile sheetlike structures which are preferably useful as separators and which are notable for a high and rapid electrolyte takeup capacity (initial wettability) and also for a high persistence of the initial wettability after storage under ambient conditions for the treated textile sheetlike structures. The inventive products also have high electrolyte retention ability.
It is a further object of the present invention to provide textile sheetlike structures which are usable as separators without their use causing extraneous materials, such as surfactants for example, to be transported into the electrolyte fluid to thereby shorten the use life of the energy store.
It is a further object of the present invention to provide textile sheetlike structures whose wetting properties change only insignificantly if at all on storage in alkaline media, such as aqueous potassium hydroxide solution.
It is a further object of the present invention to provide plasma-treated textile sheetlike structures whose wetting properties are virtually unchanged after storage for prolonged periods.
It is a further object of the present invention to provide an economical and environmentally friendly process without employment of chemicals and without emissions to water.

These objects are achieved by the treatment of a textile sheetlike structure by means of a selected plasma-supported surface modification under atmospheric pressure utilizing air as a process gas.
The present invention provides hydrophilicized textile sheetlike structures having high initial wettability and long-lasting wetting properties. These properties can be characterized by determining the height of rise of an aqueous potassium hydroxide solution.
Textile sheetlike structures having the aforementioned property profile have hitherto not been described.
The present invention relates to plasma-treated textile sheetlike structures containing manufactured fibres which have a high initial wettability (expressed by a height of rise of at least 80 mm, preferably of at least 90 mm, after 3 0 minute immersion in aqueous potassium hydroxide solution) and which after three months', preferably six months', storage at 25°C in air have a high initial wettability (expressed by a height of rise of at least 75 mm, preferably of at least 85 mm, after 30 minute immersion in an aqueous potassium hydroxide solution).
The inventive plasma-treated textile sheetlike structures preferably possess excellent stability for the wetting properties on storage in alkaline media, expressed as a height of rise of at least 20 mm and preferably of at least 35 mm after 30 minute immersion in an alkaline medium following one week's storage at 25^C in an aqueous potassium hydroxide solution. These properties are determined on a standardized textile sheetlike structure by means of the process described hereinbelow.

The inventive textile sheetlike structures can be produced in any desired manner. All sheet-forming techniques, such as weaving, laying, formed-loop knitting, drawn-loop knitting or wet or dry webbing processes can be used.
As well as textile sheetlike structures formed from staple fibres and/or from filament yarns it is also possible to use spunbondeds formed from continuous filaments.
The term "textile sheetlike structure" as used herein is to be understood as meaning wovens, drawn-loop knits, formed-loop knits, non-crimp fabrics or, in particular, porous films or nonwoven fabrics.
The inventive textile sheetlike structures contain fibres composed of synthetic polymers and have preferably been consolidated.
The inventive textile sheetlike structures can consist of any desired fibre varieties from the most diverse diameter ranges. Typical fibre diameters vary in the range from 0.01 to 200 iim and preferably from 0.05 to 5 0 (im.
As well as continuous filament fibres, these textile sheetlike structures can consist of staple fibres or contain same.
As well as homofil fibres it is also possible to use heterofil fibres or blends of the most diverse fibre varieties.
The inventive textile sheetlike structures can be produced dry or wet in any desired way known per se. Webs can be produced for example using spunbonded processes, carding processes, melt-blowing processes ^

wet-laying processes, electrostatic spinning or aerodynamic webbing processes.
Typically, the inventive textile sheetlike structures, the nonwoven fabrics in particular, have basis weights from 0.05 to 500 g/m^.
Particular preference is given to nonwoven fabrics having low basis weights in the range from 5 to 150 g/m^
A very wide range of synthetic polymers can be used, depending on the contemplated purpose.
For instance, polymers for use in batteries having acidic electrolytes are preferably polyolefins, especially polypropylene C'PP") or polyethylene ("PE"), graft or co polymers of polyolefins and a,p-unsaturated carboxylic acids or -carboxylic anhydrides, polyester, polycarbonate, polysulphone, polyphenylene sulphide, polystyrene or mixtures thereof.
Polymers for use in accumulators having basic electrolytes are preferably polyamides, polyolefins, especially polypropylene ("PP") or polyethylene ("PE"), copolymers of polyolefins and a,^-unsaturated carboxylic acids or -carboxylic anhydrides, polysulphone, polyphenylene sulphide, polystyrene or mixtures thereof.
Particular preference is given to using textile sheetlike structures formed from polyolefin fibres, especially from polypropylene fibres and/or polypropylene-polyethylene bicomponent fibres, especially core-sheath fibres having a PP core and a PE sheath. These products, as well as being low in price, are notable for high stability to chemically aggressive environments. They are preferably useful as separators for energy stores having alkaline electrolytes.

The inventive textile sheetlike structures can have been consolidated in a conventional manner, for example by mechanical or hydraulic needling or by melting of binder fibres present in the textile sheetlike structure.
It was found that the inventive products are producible by a specific plasma treatment and that similar treatment processes do not lead to products having the property profile described and especially do not lead to products having a long-lasting hydrophilicity.
According to the invention, a corona generator of the type of generators described in DE-A-42 35 766 is used for plasma treatment.
Corona generators are generators for generating voltage pulses which, applied to the primary winding of a high-voltage transformer, generate a corona discharge between a corona electrode and a counterelectrode via the secondary winding of the high-voltage transformer. The generator used according to the invention is notable in that it automatically adapts to the electrical properties of the materials to be treated and possesses a much simplified electronic circuitry.
The corona generator used according to the invention is supplied from a direct current source and consists essentially of a first resonant circuit, a switch and a second resonant circuit which has an associated high-voltage transformer. The first resonant circuit is a series-tuned resonant circuit having an inductor and a capacitor, which is connected via a switch, a diode and an inductor to the primary winding of the high-voltage transformer- The inductance of the inductor in the first resonant circuit (charging circuit) and the switching criterion of the switch in the second resonant circuit (discharging circuit), the switching

criterion being derived from the voltage across the capacitor, is selected such that the clock frequency of the voltage pulses (which occur in the generator) on the primary winding is less than the eigenfrequency of the damped oscillation of the second resonant circuit. The corona discharge path utilizes a corona electrode and an earthed counterelectrode over which the textile sheetlike structure to be treated is led. The corona electrode is provided with a dielectric sheath and is disposed at a short distance away from the counterelectrode. The discharge is consequently a barrier discharge.
The present invention thus also relates to a process for producing the above-described hydrophilicized textile sheetlike structures comprising the steps of:
a) forming a textile sheetlike structure by a textile sheet-forming technique in a conventional manner,
b) providing a space in which a barrier discharge generated with the aid of a corona generator burns,
c) transporting the textile sheetlike structure through the space in which the -barrier discharge burns, so that the textile sheetlike structure is exposed to the barrier discharge, wherein
d) the corona generator consists essentially of a first resonant circuit, a switch and a second resonant circuit which has an associated high-voltage transformer, the first resonant circuit is a series-tuned circuit which has an inductor and a capacitor which is connected via a switch, a diode and an inductor to the primary winding of a high-voltage transformer, and wherein the inductance of the inductor in the first resonant circuit and the switching criterion, which is derived from the voltage across the capacitor, for the switch in the

second resonant circuit are selected such that the clock frequency of the voltage pulses (which occur in the generator) on the primary winding is less than the eigenfrequency of the damped oscillation of the second resonant circuit.
It is particularly preferable for the textile sheetlike structure to be transported through the corona discharge at atmospheric pressure, and the corona discharge takes place in air, without addition of further gases or additives.
The plasma treatment is effected by continually passing the textile sheetlike structure through the corona discharge. Typical web speeds are 0-5-400 m/min.
The treatment is customarily carried out in air at atmospheric pressure. The treatment can be carried out in a non-oxidizing atmosphere with, for example, a noble gas, such as helium or argon, as an inert gas or with the addition of reactive gases or additives in the plasma. Typical operating pressures in the plasma range from 0.7 to 1.3 bar, preferably from 0.9 to 1.1 bar.
The inventive textile sheetlike structures can be used, especially in the form of nonwoven fabrics, in environments where chemically aggressive materials are present. Examples thereof are the use as filter materials or as separators in batteries, especially in batteries having alkaline electrolytes. These uses likewise form part of the subject-matter of the present invention.
The examples which follow describe the invention without limiting it.

General working prescription
Polyolef in nonvroven fabrics composed of core-sheath fibres having a PP core and a PE sheath were produced by the wet-laid process.
These polyolefin nonwoven fabrics were melted together at the crossing points of the fibres in a dryer.
In a second step, the polyolefin nonwoven fabrics thus produced were passed through a corona discharge produced using a corona generator as per DE-A-42 35 766.
The hydrophilicity of the resultant products immediately following corona treatment was determined by the following method:
Determination of wicking rate or height of rise of a standardized textile sheetlike structure.
The wicking rate is the rate at which an electrolyte solution (30% KOH solution) is wicked up in the nonwoven fabric by capillary forces. It is determined by measuring the rate of rise of the solution in the nonwoven fabric against the force of gravity. "What is measured is the height of rise in defined time segments.
The nonwoven fabric samples, which were 3 0 mm in width and 250 mm in length, were conditioned for 24 hours in the standard atmosphere (65% relative humidity, 20^C) before measurement. Thereafter, the nonwoven fabric samples were attached above a cloth which contained 30% KOH solution in a perpendicular position and moved downwardly until about 10 mm of the nonwoven fabric dipped into the electrolyte, At the same time, a stopwatch was started to take the time.

The KOH solution rose in the nonwoven fabric sample and was read off as height of rise in mm after a time segment of 30 minutes.
Instead of the nonwoven fabric it is also possible to use other types of the inventive textile sheetlike structures.
Immediately following the corona treatment, the products obtained were placed in 30% aqueous potassium hydroxide solution at 2 5°C for one week and thereafter the height of rise was determined as per the method described above.
Media resistance was determined by ageing in electrolyte solution as per the method described hereinbelow:
Nonwoven fabric samples 30 mm in width and 2 50 mm in length were stored in 30% aqueous potassium hydroxide solution at 7 0°C for 1 week, then washed pH-neutral with completely ion-free water and dried at 70^C in a circulating air drying cabinet. Subsequently, the wicking rate or the height of rise was determined by the method described above.
The nonwoven fabrics were also stored in air at 25°C for three or six months following the corona treatment. The hydrophilicity of the stored products was subsequently determined by the method described above.
Example 1
A polyolefin nonwoven fabric having a basis weight of 50 g/m^ was treated in an atmospheric pressure plasma at 1.2 m/min as per the above prescription.
The hydrophilicity of the nonwoven fabric thus treated was characterized as per the above-described measuring

prescription immediately after the plasma treatment and also after one week's storage in 30% aqueous KOH.
An 85 mm rise of the KOH solution was observed after 30 minutes. The height of rise was 35 mm after one week's storage of the nonwoven fabric in the KOH solution.
No change in hydrophilicity was observed after 3 or 6 months of ageing of the plasma-treated nonwoven fabric in air at 25^C. The KOH solution rose by 85 mm after 3 0 minutes.
Example 2
A polyolefin nonwoven fabric having a basis weight of 50 g/m^ was treated in an atmospheric pressure plasma at 0.6 m/min as per the above prescription.
The hydrophilicity of the nonwoven fabric thus treated was characterized as per the above-described measuring prescription immediately after the plasma treatment and also after one week's storage in 30% aqueous KOH,
A 90 mm rise of the KOH solution was observed after 3 0 minutes. The height of rise was 45 mm after one week's storage of the nonwoven fabric in KOH solution.
No change in hydrophilicity was observed after 3 or 6 months of ageing of the plasma-treated nonwoven fabric in air at 25°C. The KOH solution rose by 90 mm after 30 minutes.
Example 3
A polyolefin nonwoven fabric having a basis weight of 60 g/m^ was treated and characterized as described in Example 1.

A 90 mm rise of the KOH solution was observed after 30 minutes. The height of rise was 25 mm after one week's storage of the nonwoven fabric in the KOH solution.
No change in hydrophilicity was observed after 3 or 6 months of ageing of the plasma-treated nonwoven fabric in air at 25^C. The KOH solution rose by 90 mm after 3 0 minutes.
Example 4
A polyolefin nonwoven fabric having a basis weight of 60 g/m^ was treated and characterized as described in Example 2.
A 102 mm rise of the KOH solution was observed after 30 minutes. The height of rise was 40 mm after one week's storage of the nonwoven fabric in the KOH solution.
No change in hydrophilicity was observed after 3 or 6 months of ageing of the plasma-treated nonwoven fabric in air at 25°C. The KOH solution rose by. 102 mm after 3 0 minutes,
Example 5 (comparison)
A polyolefin nonwoven fabric having a basis weight of 50 g/m^ was treated at 1 m/min as per the above prescription but by using a commercially available generator which does not follow the above-described characteristic and characterized as described above.
A 48 mm rise of the KOH solution was observed after 30 minutes. The height of rise was 0 mm after one week's storage of the nonwoven fabric in the KOH; solution.

A 13 mm rise of the KOH solution was observed after 30 minutes following 3 months' ageing of the plasma-treated nonwoven fabric in air at 25°C.



Claims
Plasma-treated textile sheetlike structures containing manufactured fibres which have a high initial wettability (expressed by a height of rise of at least 80 mm after 30 minute immersion in aqueous potassium hydroxide solution) and which after three months' ageing at 25^C in air have a high initial wettability (expressed by a height of rise of at least 75 mm after 30 minute immersion in an aqueous potassium hydroxide solution).
Plasma-treated textile sheetlike structures according to Claim 1, characterized in that these after six months' storage at 25°C in air have a high initial wettability (expressed by a height of rise of at least 75 mm after 30 minute immersion in an aqueous potassium hydroxide solution.
Plasma-treated textile sheetlike structures according to Claim 1, characterized in that they are a nonwoven or a porous film.
Plasma-treated textile sheetlike structures according to Claim 1, characterized in that they contain polyolefin fibres.
Plasma-treated textile sheetlike structures according to Claim 3, characterized in that the polyolefin fibres are polypropylene fibres and/or bicomponent fibres formed from polypropylene and polyethylene.
Plasma-treated textile sheetlike structures according to Claim 4, characterized in that it induces a height of rise of at least 90 mm after 30 minutes' immersion in a potassium hydroxide solution and a height of rise of at least 15 mm

after one week's storage in a potassium hydroxide solution at 25^C.
Plasma-treated textile sheetlike structure according to Claim 1, characterized in that it is consolidated by melting of binder fibres.
Process for producing hydrophilicized textile sheetlike structures according to Claim 1 comprising the steps of:
a) forming a textile sheetlike structure by a textile sheet-forming technique in a conventional manner,
b) providing a space in which a barrier discharge generated with the aid of a corona generator burns,
c) transporting the textile sheetlike structure through the space in which the barrier discharge burns, so that the textile sheetlike structure is exposed to the barrier discharge, wherein
d) the corona generator consists essentially of a first resonant circuit, a switch and a second resonant circuit which has an associated high-voltage transformer, the first resonant circuit is a series-tuned circuit which has an inductor and a capacitor which is connected via a switch, a diode and an inductor to the primary winding of a high-voltage transformer, and wherein the inductance of the inductor in the first resonant circuit and the switching criterion, which is derived from the voltage across the capacitor, for the switch in the second resonant circuit are selected such that the clock frequency of the voltage pulses (which occur in the generator) on the primary
winding is less than the eigenfrequency of the damped oscillation of the second resonant circuit.

Process according to Claim 8, characterized in that the transporting of the textile sheetlike structure through the barrier discharge is effected at atmospheric pressure and in that the barrier discharge takes place in air.
Use of the plasma-treated textile sheetlike structure according to Claim 1 as a separator for electrochemical cells.
Use according to Claim 10, characterized in that the electrochemical cell is a battery or an accumulator, especially an alkaline battery or an alkaline accumulator.

A plasma treated textile sheetlike structures substantially as herein described and exemplified.


Documents:

239-che-2004-abstract.pdf

239-che-2004-claims duplicate.pdf

239-che-2004-claims original.pdf

239-che-2004-correspondnece-others.pdf

239-che-2004-correspondnece-po.pdf

239-che-2004-description(complete) duplicate.pdf

239-che-2004-description(complete) original.pdf

239-che-2004-form 1.pdf

239-che-2004-form 19.pdf

239-che-2004-form 26.pdf

239-che-2004-form 3.pdf

239-che-2004-form 5.pdf


Patent Number 203495
Indian Patent Application Number 239/CHE/2004
PG Journal Number 05/2007
Publication Date 02-Feb-2007
Grant Date 16-Nov-2006
Date of Filing 18-Mar-2004
Name of Patentee M/S. CARL FREUDENBERG KG
Applicant Address HOHNERWEG 2-4, 69469 WEINHEIM,
Inventors:
# Inventor's Name Inventor's Address
1 PETER KRITZER ELSTER 3, 67147 FORST,
2 BIRGIT SEVERICH EICHELSHEIMER STR. 50, 68163 MANNHEMI,
3 GERHARD SCHOPPING MUHLWEG 4A, 69502 HEMSBACH,
4 WOLFGANG HALLSTEIN AM HOFACKER 4, 64658 FURTH,
5 STEOHAN RUTZ GRUNDELBACHSTRASSE 34, 69469 WEINHEIM,
PCT International Classification Number D06M 10/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10319057.0-43 2003-04-25 Germany