EP3560301B1 - Nozzle arrangement and device for generating an atmospheric plasma jet - Google Patents

Description

The invention relates to a nozzle arrangement for a device for generating an atmospheric plasma jet with an inlet through which an atmospheric plasma jet can be introduced into the nozzle arrangement, and with a channel which is connected to the inlet so that a through the inlet into the nozzle arrangement introduced plasma jet is passed through the channel. The invention also relates to a device for generating an atmospheric plasma jet.

The invention also relates to a method for plasma treatment of a material or a plastic film and a plasma-treated nonwoven material.

In the manufacture of diapers, bandages or pads (so-called hospital pads), layers of non-woven fabric, especially so-called absorption layers and distribution layers, are used with which liquid is to be quickly guided from the skin surface into an absorbent material, typically into a layer with so-called superabsorbents (superabsorbent polymers) . In practice, the distribution layers are also often referred to as AQL (Acquisition Layer) or ADL (Acquisition Distribution Layer).

These nonwoven layers, especially ADLs / AQLs, are available in different qualities. The quality of the nonwoven layer results from the so-called liquid strike-through time, determined in accordance with ISO 9073-13: 2006, which is a measure of the speed with which the liquid is absorbed and passed on by the nonwoven layer becomes. The lower the The penetration time, the better the function of the nonwoven layer in the diaper, sanitary napkin or pad.

Since the nonwoven layers, especially the ADLs / AQLs, make up a significant proportion of the material costs of the diaper, bandage or pad, low-quality nonwoven layers with long penetration times are often used for inexpensive products, which impairs the function of the diaper, bandage or pad. For higher quality products, nonwoven layers of higher quality are used. However, on the one hand these are more expensive and on the other hand they have a higher weight per unit area, which also results in a higher material consumption and a higher weight of the diaper, sanitary napkin or pad.

There is a need to improve the penetration times of thin or inexpensive nonwoven layers or ADLs / AQLs in order to be able to produce good quality diapers, sanitary napkins or pads more cheaply in this way.

The object of the present invention is therefore to provide a device and a method with which, in particular, the penetration time of nonwoven layers, in particular of ADLs / AQLs, can be improved.

According to a first teaching, this object is achieved in a nozzle arrangement for a device for generating an atmospheric plasma jet with an inlet through which an atmospheric plasma jet can be introduced into the nozzle arrangement, and with a channel which is connected to the inlet so that a through the inlet plasma jet introduced into the nozzle arrangement is passed through the channel, solved according to the invention in that several nozzle openings are provided in the channel wall along the channel through which a plasma jet directed through the channel can exit the nozzle arrangement.

Furthermore, the object is given to a device for generating an atmospheric plasma jet with a discharge space, the device is set up to generate an atmospheric plasma jet in the discharge space, achieved according to the invention in that a nozzle arrangement of the type described above is connected to the discharge space in such a way that a plasma jet generated in the discharge space is introduced into the inlet of the nozzle arrangement.

It has been found that the penetration time of nonwovens can be improved by treating the nonwoven with an atmospheric plasma jet. However, it turned out that plasma nozzles known from the prior art for generating an atmospheric plasma jet are poorly suited for this purpose, since the thin nonwovens used for diapers, sanitary towels and covers are very temperature-sensitive and quickly damaged when exposed to an atmospheric plasma jet especially crack or melt. Corona treatment or treatment with dielectrically impeded discharge is not a sensible alternative either, as this leads to holes in the nonwovens due to the streamers and discharge filaments associated with it, and in contrast to a plasma jet only has a very superficial effect and only causes a slight reduction in the penetration time . A gentler treatment would indeed be possible with low-pressure plasma, but such systems are expensive and are difficult to integrate into production lines, in particular not with the typically required production throughput.

In contrast, with the nozzle arrangement described above and the device described above, a plasma jet can be generated whose intensity is sufficient on the one hand to treat the nonwovens in such a way that their penetration time is reduced, and on the other hand is not too strong so that the nonwovens are not damaged. In a similar way, the nozzle arrangement and device described have also proven to be well suited for treating other sensitive substances, thin plastic films or thin metal foils with plasma, which would be damaged by a plasma jet from a conventional plasma nozzle. The The nozzle arrangement or the device is preferably used for the plasma treatment of substances or foils, in particular plastic foils or metal foils. The nozzle arrangement is provided for a device for generating an atmospheric plasma jet. The nozzle arrangement can, for example, be formed integrally with such a device. Alternatively, the nozzle arrangement can also be designed as a separate component, which can, for example, be detachably connected to the rest of the device, for example in a device for generating an atmospheric plasma jet with an exchangeable nozzle head or an exchangeable nozzle arrangement.

The nozzle assembly has an inlet. If the nozzle arrangement is designed, for example, as an integral part of a device for generating an atmospheric plasma jet, the inlet can also be an imaginary transition from the rest of the device to the nozzle arrangement, without there having to be a physical interruption between the rest of the device and the nozzle arrangement.

An atmospheric plasma jet can be introduced into the nozzle arrangement through the inlet. For this purpose, the nozzle arrangement is preferably connected or can be connected to a device for generating an atmospheric plasma jet in such a way that the plasma jet passes through the inlet into the nozzle arrangement during operation. The nozzle arrangement preferably has corresponding coupling means in the region of the inlet, for example a thread, in order to connect the nozzle arrangement to a device for generating an atmospheric plasma jet.

The nozzle arrangement has a channel which is connected to the inlet in such a way that a plasma jet introduced into the nozzle arrangement through the inlet is guided through the channel. The channel can have a circular or semicircular cross-section, for example.

Several nozzle openings are provided in the channel wall along the channel. For this purpose, the channel preferably has an essentially straight channel section in which the nozzle openings are arranged one behind the other. The number of nozzle openings can be selected as required, whereby the intensity of the individual partial jets can be reduced by increasing the number of nozzle openings. Preferably, however, at least five, more preferably at least ten nozzle openings are provided in the channel in order to achieve a weakening of the partial jet intensities suitable for the treatment of sensitive materials, preferably sensitive substances and foils, in particular plastic foils or metal foils. The nozzle openings can, for example, be circular, oval, slot-like or have a different geometry.

A plasma jet guided through the channel can exit the nozzle arrangement through the nozzle opening. The nozzle openings lead out of the channel to the outside. The plasma jet guided through the channel then penetrates outward through the nozzle openings so that it emerges from the nozzle arrangement in the form of several partial jets. This division of the plasma beam into several partial beams achieves on the one hand that the plasma beam can act over a greater width. On the other hand, it is achieved that the intensity of the individual partial beams can be reduced in such a way that sensitive substances, in particular nonwovens, or thin plastic or metal foils are not damaged by the partial beams, but can nevertheless be effectively plasma-treated.

The device for generating an atmospheric plasma jet has a discharge space and is designed to generate an atmospheric plasma jet in the discharge space. Such devices are known in principle from the prior art, for example from DE 195 32 412 C2 .

WO2016 / 083539 A1 discloses another apparatus for generating multiple cold plasma jets at atmospheric pressure.

In particular, the device has a housing, for example a tubular housing, in which the discharge space is provided.

The atmospheric plasma jet is generated in the discharge space preferably by means of an electrical discharge in a working gas flow. The electrical discharge excites and partially ionizes the working gas, so that a plasma is formed that emerges from the discharge space as a plasma jet as a result of the working gas flow.

For this purpose, the discharge space has, in particular, a gas inlet through which the working gas flow can pass into the discharge space. For the electrical discharge, an internal electrode is preferably arranged in the discharge space. Furthermore, an outer electrode is preferably provided which can be formed, for example, by the housing itself, for example by a metal tube used as the housing.

The nozzle arrangement described above is connected to the discharge space. For this purpose, the housing and the nozzle arrangement can have corresponding connecting means, for example threads, with which the nozzle arrangement can be connected to the discharge space in such a way that a plasma jet generated in the discharge space is guided through the inlet of the nozzle arrangement.

According to a second teaching, the above-mentioned object is further achieved according to the invention by using the device described above for plasma treatment of a material, in particular a substance or a film, in particular a plastic film or a metal film. The fabric can in particular be a nonwoven fabric.

Furthermore, the above-mentioned object is achieved according to the invention by a method for plasma treatment of a substance or a film, in particular a plastic film or metal film, using the device described above, in which an atmospheric plasma jet is generated with the device so that the plasma jet emerges in the form of several partial jets from the nozzle openings in the duct wall, and in which a surface of a substance or a film, in particular a plastic film or metal foil, is exposed to the partial jets of the plasma jet.

By dividing the plasma jet into individual partial jets, on the one hand a wider area of the substance or the film, in particular the plastic film or the metal film, can be treated at the same time, so that higher throughputs can be achieved in the plasma treatment. On the other hand, an intensity of the individual partial beams can be achieved so that the substance or the film, in particular the plastic film or the metal film, can be effectively plasma-treated without damaging it. In particular, it can be achieved that the temperature of the substance or the film is consistently below 100 ° C or even below 50 ° C during the plasma treatment.

For example, air, hydrogen-nitrogen mixtures, nitrogen or noble gases can be used as the working gas to generate the plasma jet. Nitrogen (N ₂ ) or noble gases, in particular argon, are preferably used as the working gas, possibly also in combination, since in this way the service life of the plasma species in the plasma jet is extended so that the plasma still has a sufficiently high activity even after passing through the channel having. When nitrogen is used as the working gas, the nitrogen concentration in the working gas is preferably at least 98% by weight, in particular at least 99.5% by weight.

The material to be treated, in particular the substance or the film to be treated, is preferably provided in the form of a web, for example from a roll or in a production line, and guided past the nozzle arrangement so that the partial jets exiting the nozzle openings onto the material, in particular onto the substance or the foil.

The fabric is preferably a nonwoven fabric, which can in particular consist essentially of synthetic fibers, for example polypropylene or polyethylene fibers, of natural fibers, for example cotton or viscose fibers, and / or of inorganic fibers, for example glass fibers. It has been found that the plasma treatment of a nonwoven fabric with the method described above causes functional groups to form on the individual fibers of the nonwoven fabric, which increase the hydrophilicity of the fibers so that the fabric can absorb liquid better.

Furthermore, it has been shown that the plasma treatment with the described method leads to the thickness of the nonwoven fabric increasing with a corresponding reduction in density. In tests, increases in thickness by a factor of five were observed. It has been found that this leads to a shorter penetration time of the nonwoven fabric. This can be explained by the fact that with the increase in thickness and decrease in density, capillaries are increasingly formed essentially perpendicular to the direction of the fabric, so that liquid can be transported through the nonwoven fabric more quickly. These effects result in a shorter penetration time of the nonwoven fabric.

In tests, a reduction to half or even to a third of the original penetration time of the untreated nonwoven was achieved with the plasma treatment. For example, the plasma treatment with a thin, inexpensive nonwoven fabric with a weight per unit area of 30 g / m ^{2 achieved} penetration times that correspond to those of a high quality nonwoven fabric with a weight of 90 g / m ² . This means that the process can be used to produce light, inexpensive nonwovens with a good penetration time.

Accordingly, the weight per unit area of the nonwoven, in particular of the ADL or AQL, is preferably less than 90 g / m ² , in particular less than 50 g / m ² . The described plasma treatment of thin nonwovens increases the thickness of the nonwovens and improves their penetration time, in particular to values that were previously only could be achieved by nonwovens with a higher basis weight. The thickness of the nonwoven fabric is preferably less than 5 mm before the plasma treatment.

Tests have also shown that the increase in thickness of the nonwoven fabric caused by the plasma treatment is very stable and is maintained over time and under high pressure. In tests, the thicknesses of the plasma-treated nonwovens were retained even under pressures of 50,000 to 300,000 Pa, which corresponds to the typical pressures in a diaper packaging, since the diapers are strongly compressed during packaging. After the pressure was released, the nonwovens essentially returned to their previous thickness after the plasma treatment.

Furthermore, it was found that the properties of the nonwovens plasma-treated with the described method are retained over a long period of time, in particular because the plasma jet penetrates deep into the nonwoven, while superficial corona treatment only leads to short-term effects.

Correspondingly, the above-mentioned object is also achieved according to the invention by a plasma-treated nonwoven fabric, in particular ADL or AQL, produced by a method with the following steps: providing a nonwoven fabric and plasma treating the nonwoven fabric with the method described above. Furthermore, the above-mentioned object is achieved according to the invention by a hygiene article for absorbing liquids, in particular a bandage, diaper or pad, having a layer made of the plasma-treated nonwoven fabric described above. Due to the improved penetration time, such hygiene articles are of higher quality and at the same time have low production costs.

A nonwoven fabric plasma-treated with the described method can be separated from untreated nonwovens of the same type, in particular due to the lower density caused by the plasma treatment and the hydrophilization caused by the plasma treatment by the functional Distinguish groups on the fibers. For example, if an ADL / AQL material normally has a density of 90 kg / m ³ , the density of the plasma-treated material is in particular less than 45 kg / m ³ . The hydrophilization can be proven by measuring the contact angle of water on the fibers. In the case of plasma-treated nonwovens, this is in particular less than 40 ° (measured directly on the fibers of the nonwoven), while it is higher in the case of untreated nonwovens. The functional groups on the fibers can also be detected directly, for example by means of X-ray photoelectron spectroscopy (XPS).

The method is also suitable for the plasma treatment of foils, in particular plastic foils or metal foils. By plasma treatment of foils, they can be prepared for a subsequent printing process or for gluing the foils. The method achieves good hydrophilization of the film surface without damaging the film. In contrast, earlier attempts to treat foils with dielectrically impeded discharges only led to minor improvements in hydrophilization (to a maximum of 40 to 55 mN / m). The use of conventional plasma nozzles often resulted in damage to the foils due to the high thermal load. The method is particularly suitable for thin foils with a thickness of preferably less than 0.1 mm, more preferably less than 0.05 mm, in particular less than 0.02 mm.

In the following, various embodiments of the nozzle arrangement, the device, the use, the method, the plasma-treated nonwoven fabric and the hygiene article for absorbing liquids are described, the individual embodiments in each case correspondingly for the nozzle arrangement, the device, the use, the method, the plasma-treated non-woven fabric and the hygiene article for absorbing liquids can be used. Furthermore, the individual embodiments can also be combined with one another.

In one embodiment, the channel has a straight section and the nozzle openings are arranged in the channel wall in the direction of extent of the channel. In this way, a curtain can be produced from partial beams arranged next to one another, so that a nonwoven fabric or a film can be treated simultaneously over a large width.

The nozzle openings are preferably arranged over a length of the channel of at least 50 mm, preferably at least 80 mm, in order to generate a wide plasma curtain and to distribute the intensity of the plasma jet over a larger area, so that the thermal load on the treated material is reduced.

In a further embodiment, the channel is connected to the inlet on both sides, so that a plasma jet introduced through the inlet into the nozzle arrangement is guided into the channel from both sides. In particular, the channel has a first and a second end which are each connected to the inlet. For this purpose, a distribution channel is preferably provided between the inlet and the channel, through which the plasma jet is directed to both ends of the channel. The introduction of the plasma jet into the channel on both sides results in a more even distribution of the plasma jet intensity among the individual partial jets. In particular, the intensity is prevented from decreasing continuously from one end to the other end of the channel. This enables a more uniform plasma treatment to be achieved.

In a further embodiment, a gas feed is provided in order to conduct a gas, preferably nitrogen, separately from the plasma jet into the channel. For this purpose, the channel preferably has an additional gas inlet to which a gas supply can be connected. In a corresponding embodiment of the method, a gas, preferably nitrogen, is introduced separately into the channel in addition to the plasma jet. In this way, an additional cooling of the plasma jet is achieved, so that with the out of the nozzle openings of the nozzle arrangement exiting partial beams an even gentler treatment, especially of sensitive nonwovens, is possible.

In a further embodiment, the diameter of the nozzle openings in the duct wall corresponds at most to a quarter of the duct diameter. In this way, an excessive pressure drop in the channel is prevented, so that the partial beams have a more uniform intensity.

In a further embodiment, the cross-section of the channel widens with increasing distance from the inlet. It was recognized that this measure can counteract a pressure drop in the duct, so that partial beams of more uniform intensity are achieved.

In a further embodiment, the nozzle arrangement is constructed in several parts with a nozzle element that includes the channel with the nozzle openings, and with a distributor element that includes a distributor channel through which a plasma jet introduced through the inlet is guided to the channel on one or both sides. In this way, the nozzle arrangement can be manufactured more easily. For example, the nozzle element can have a groove made in a surface which, in the assembled state, forms the channel with the other parts of the nozzle arrangement. As a result, the duct running inside the nozzle arrangement can be produced more easily. The distributor element can, for example, have two parts, each of which has a groove on the surface, with the distributor channel resulting from the grooves in the assembled state. The nozzle arrangement can also be produced more easily in this way.

The distributor channel of the distributor element preferably has an inlet and two outlets connected to the inlet in order to guide the plasma jet from the one inlet to both ends of the channel.

In a further embodiment, the nozzle arrangement has a heat sink, in particular a heat sink with cooling fins for air cooling. In this way, the heat introduced into the nozzle arrangement with the plasma jet can be better released to the outside, so that the nozzle arrangement does not heat up too much. Furthermore, the temperature of the partial jets of the plasma jet can also be reduced in this way.

In a further embodiment, the cross section of the channel in the area of a nozzle opening is shaped in such a way that a fictitious central plane, which is located in the middle between a fictitious first tangent plane of the cross section through the nozzle opening and a fictitious second tangent plane of the cross section opposite and parallel to the first tangent plane runs, divides the cross-section into a first cross-sectional area at the nozzle opening and a second cross-sectional area opposite the nozzle opening, the cross-sectional area of the first cross-sectional area differing from the cross-sectional area of the second cross-sectional area, preferably by at least 5%, in particular by at least 10%.

It was found that such an asymmetry of the channel cross-section allows a more uniform distribution of the plasma beam intensity to the individual partial beams. With the asymmetry described, the channel cross-section has a different cross-sectional area in the area from a nozzle opening up to half its height above the nozzle opening than in the remaining area of the channel cross-section.

The embodiment defines the cross section of the channel in the area of a nozzle opening. However, the channel preferably has a corresponding cross-section in the area of several nozzle openings, preferably along its course from the first to the last nozzle opening.

The duct cross-section is divided by a fictitious central plane. This fictitious central plane does not actually exist but only serves to define the first and second cross-sectional areas, the cross-sectional areas of which are compared with one another.

The fictitious central plane runs in the middle between a fictitious first tangent plane of the cross section through the nozzle opening and a fictitious second tangent plane of the cross section that is opposite this and parallel to the first tangent plane. The middle between two planes is understood to mean that the middle plane is at the same distance from the first and the fictitious second tangent plane. A tangent plane of the cross section is understood to mean a plane which touches the cross section of the channel, but does not intersect. The first tangent plane of the cross section runs through the nozzle opening, i.e. through the point where the nozzle opening meets the channel. The second tangent plane is opposite the first tangent plane. The cross section of the channel is accordingly located between the first and the second tangent plane. Like the middle plane, the first and second tangent plane are also fictitious and serve to define the fictitious middle plane.

In one embodiment, the cross section of the channel has two opposite circular segments with different radii. Such a cross section can be easily produced, for example, by means of two offset, parallel bores with different boring diameters. As a result, the manufacturing costs can be kept low.

In a further embodiment, the cross-sectional area of the second cross-sectional area is larger than the cross-sectional area of the first cross-sectional area. In this way it was possible to achieve a particularly even distribution of the plasma beam intensity among the individual partial beams. If the cross-section of the channel has, for example, two opposite circular segments with different radii, the nozzle opening is preferably in the area of the Circle segment arranged with the smaller radius, in particular in its apex.

In a further embodiment, the nozzle arrangement is designed in several parts with a first part, in the surface of which a first recess is made, and with a second part, in the surface of which a second recess is made, wherein the first and the second part abut one another in such a way that the first and second indentations face each other and form the channel. In this way, the first recess forms a first part of the channel cross section and the second recess forms a second part of the channel cross section. If the two depressions are arranged opposite one another, the entire cross-section of the channel results.

This embodiment allows a particularly simple production of the channel. This is particularly advantageous if the channel has an asymmetrical cross-section, for example in accordance with one of the previously described embodiments with a first and second cross-sectional area having different cross-sectional areas, or if the channel has a cross-section that changes, for example, tapering along its direction of extension. In addition to the first and second parts, the nozzle arrangement can also have further parts.

The first part of the nozzle arrangement can be, for example, a nozzle element which comprises the nozzle openings. The nozzle openings then preferably emanate from the first recess.

The second part of the nozzle arrangement can be, for example, a distributor element which comprises a distributor channel through which a plasma jet introduced through the inlet is guided to the channel on one or both sides.

In one embodiment, the first part of the nozzle arrangement has a recess with a circular segment-shaped cross section with a first radius and the second Part of the nozzle arrangement has a recess with a circular segment-shaped cross section with a second radius which differs from the first radius. The first and second depressions placed next to one another then result in a cross section made up of two opposing circular segments of different radii. The second radius is preferably smaller than the first radius.

In a further embodiment, the device is set up to generate an atmospheric plasma jet by means of an arc-like discharge in a working gas, the arc-like discharge being able to be generated by applying a high-frequency high voltage between electrodes. In a corresponding embodiment of the method, the atmospheric plasma jet is generated by means of an arc-like discharge in a working gas, the arc-like discharge being produced by applying a high-frequency high voltage between electrodes.

The working gas used is preferably nitrogen (N ₂ ) or a noble gas such as argon (Ar) or helium (He) or a nitrogen-noble gas mixture.

A high-frequency high voltage is typically a voltage of 1 to 100 kV, in particular 1 to 50 kV, preferably 2 to 20 kV, at a frequency of 1 to 300 kHz, in particular 1 to 100 kHz, preferably 10 to 100 kHz, more preferably 10 - 50 kHz understood. In this way, a reactive plasma jet can be generated which enables effective plasma treatment, in particular of nonwovens, so that their penetration time is reduced. At the same time, a plasma jet generated in this way has a relatively low temperature. Due to the additional division of the plasma beam into several partial beams, an intensity of the partial beams is achieved that avoids damage to sensitive materials such as fabrics and plastic films.

In a further embodiment, the device has an internal electrode arranged within the discharge space. Between the inner electrode and In particular, a high-frequency high voltage can be applied to the housing in order to generate an arc-like discharge in a working gas flowing through the discharge space, so that a plasma jet is formed. Devices with such an internal electrode enable the generation of a stable discharge and therefore a stable plasma jet.

In a further embodiment, the device is used for the plasma treatment of a nonwoven fabric, in particular for or during the production of diapers, sanitary towels or covers. It has been shown that the device is particularly suitable for the plasma treatment of thin nonwovens, such as those used in the production of diapers, sanitary towels or covers, in particular ADL or AQL, since these sensitive materials can be effectively plasma treated in this way without to damage or destroy them.

In a further embodiment, the material, in particular the substance or the film, in particular the plastic film or metal film, is in the form of a web and is transported past the nozzle openings of the device. In this way, the device or the method can be easily integrated into a process line, for example into a process line for the production of nonwovens for hygiene articles or in a process line for the production of hygiene articles themselves. The juxtaposed nozzle openings are preferably at right angles to the transport direction, so that the fabric or the plastic film can be treated over a corresponding width. In this way, the substance or the plastic film can be plasma-treated with a high throughput. In laboratory tests, a reduction in the penetration time of the nonwoven by more than 25% was achieved using a single device and a throughput of 60 m of nonwoven web per minute. By using several devices, for example four devices with correspondingly four nozzle arrangements, the throughput can be increased to 240 m / min, for example. increase, so that the typical production throughputs in the manufacture of nonwovens for hygiene articles can be achieved.

It is also conceivable to use the device or the method to post-treat hygiene articles that have in principle been completely manufactured, such as bandages, diapers or covers, in order to achieve the desired improvement in the quality of the hygiene articles.

The material, in particular the substance or the film, in particular the plastic film or metal film, can be plasma-treated over the entire width. Alternatively, the material, in particular the substance or the film, in particular plastic film or metal film, can also be plasma-treated only over a partial area of the width. This is particularly advantageous in the case of nonwovens for the production of hygiene articles for absorbing liquids. If, for example, only an area in the middle of the nonwoven is plasma-treated, while strips remain untreated on the side, this nonwoven can be used to produce an absorption and distribution layer for a diaper or sanitary napkin, which is highly hydrophilic in the middle so that it absorbs liquids quickly can, but is less hydrophilic on the sides, so that no liquid can escape from the edge of the diaper or sanitary napkin. The method described accordingly also allows a targeted plasma treatment of individual areas of a nonwoven or, in general, of a material or a plastic film.

According to the method, a region of the fabric, in particular nonwoven fabric, is preferably plasma-treated, which in the case of the hygiene article to be manufactured with fabric for receiving and / or distributing liquid, in particular for guiding a liquid to a layer arranged below the region of the fabric, in particular a Superabsorbent layer, is provided. In a corresponding embodiment of the hygiene article, the layer of plasma-treated nonwoven fabric is plasma-treated in an area which is provided for receiving and / or distributing liquid, in particular for guiding a liquid to a layer arranged below this area, in particular a superabsorbent layer, for example a Area in the middle a diaper or a napkin, which is arranged, for example, between hydrophobic or liquid-impermeable areas.

In a further embodiment, the material or the film, in particular plastic film or metal film, is transported over two rollers at the same rotational speed, the device being arranged between the two rollers. Additionally or alternatively, the substance or the film, in particular the plastic film or metal film, is guided over a treatment table, such as an aluminum plate, in the area of the plasma treatment. The aforementioned measures can minimize tensile forces on the fabric or the foil, in particular the plastic foil or metal foil, during the treatment, thereby avoiding damage to the fabric or the foil, in particular the plastic foil or metal foil, during the plasma treatment. In the transport direction behind the area of the plasma treatment, an extraction system can be provided in order to extract nitrogen oxides or ozone that arise during the generation of the plasma jet. For example, the suction can be integrated into the treatment table.

In a further embodiment, the device comprises a rotary drive which is designed to rotate the nozzle arrangement about an axis of rotation during operation. In this way, the area of action of the partial jets of the plasma jet emerging from the nozzle openings can be enlarged. The axis of rotation can for example be oriented essentially perpendicular to the direction of extent of the channel or parallel to the partial jets emerging from the nozzle openings, so that the partial jets sweep over an essentially circular area when the nozzle arrangement rotates.

Alternatively, the axis of rotation can also be oriented essentially parallel to the direction of extent of the channel. This also enables, for example, an internal treatment of a pipe surface.

In a further embodiment, the material, in particular the substance or the film, is exposed to the partial jets of the plasma jet in the atmospheric pressure range. It was recognized that the partial jets emerging from the nozzle arrangement can also be used to treat sensitive materials such as, for example, fabrics, in particular nonwovens, or foils, in particular plastic or metal foils, without damage in the atmospheric pressure range. As a result, it is possible in particular to dispense with an arrangement of the material to be acted upon and / or the nozzle arrangement in a vacuum chamber.

In contrast, in other plasma treatment methods from the prior art, sensitive materials were arranged in a vacuum chamber in order to achieve sufficient attenuation of the plasma for the damage-free treatment of sensitive materials. In addition to the additional costs for the vacuum chamber, due to the necessary inward and outward transfer processes of the material to be treated into the negative pressure chamber, this also increases the outlay for performing the plasma treatment.

Since the above-described device or the described nozzle arrangement also enables the treatment of sensitive materials in atmospheric pressure, a negative pressure or vacuum chamber for the material to be treated can be dispensed with, so that the method can be carried out simply and inexpensively. In particular, the process can be carried out inline, i.e. within a continuously operated process section, since no entry and exit processes into a negative pressure or vacuum chamber that interrupt continuous operation are required.

1. 1. Düsenanordnung für eine Vorrichtung zur Erzeugung eines atmosphärischen Plasmastrahls mit einem Einlass, durch den ein atmosphärischer Plasmastrahl in die Düsenanordnung eingeleitet werden kann, und mit einem Kanal, der so mit dem Einlass verbunden ist, dass ein durch den Einlass in die Düsenanordnung eingeleiteter Plasmastrahl durch den Kanal geleitet wird, wobei entlang des Kanals mehrere Düsenöffnungen in der Kanalwand vorgesehen sind, durch die ein durch den Kanal geleiteter Plasmastrahl aus der Düsenanordnung austreten kann.
2. 2. Düsenanordnung nach Ausführungsform 1, wobei der Kanal einen geraden Abschnitt aufweist, und die Düsenöffnungen in Erstreckungsrichtung des Kanals in der Kanalwand angeordnet sind.
3. 3. Düsenanordnung nach Ausführungsform 1 oder 2, wobei der Kanal beidseitig mit dem Einlass verbunden ist, so dass ein durch den Einlass in die Düsenanordnung eingeleiteter Plasmastrahl von beiden Seiten in den Kanal geleitet wird.
4. 4. Düsenanordnung nach einer der Ausführungsformen 1 bis 3, wobei der Durchmesser der Düsenöffnungen in der Kanalwandung höchsten einem Viertel des Kanaldurchmessers entspricht.
5. 5. Düsenanordnung nach einer der Ausführungsformen 1 bis 4, wobei der Querschnitt des Kanals sich mit zunehmendem Abstand vom Einlass aufweitet.
6. 6. Düsenanordnung nach einer der Ausführungsformen 1 bis 5, wobei die Düsenanordnung mehrteilig ausgebildet ist mit einem Düsenelement, das den Kanal mit den Düsenöffnungen umfasst, und mit einem Verteilerelement, das einen Verteilerkanal umfasst, durch den ein durch den Einlass eingeleiteter Plasmastrahl ein- oder beidseitig zum Kanal geleitet wird.
7. 7. Düsenanordnung nach einer der Ausführungsformen 1 bis 6, wobei der Querschnitt des Kanals im Bereich einer Düsenöffnung derart geformt ist, dass eine fiktive Mittelebene, die in der Mitte zwischen einer fiktiven ersten Tangentenebene des Querschnitts durch die Düsenöffnung und einer dieser gegenüberliegenden und zu der ersten Tangentenebene parallelen fiktiven zweiten Tangentenebene des Querschnitts verläuft, den Querschnitt in einen ersten Querschnittsbereich an der Düsenöffnung und einen zweiten Querschnittsbereich gegenüber der Düsenöffnung teilt, und wobei sich die Querschnittsfläche des ersten Querschnittsbereichs von der Querschnittsfläche des zweiten Querschnittsbereichs unterscheidet, vorzugsweise um mindestens 5%, insbesondere um mindestens 10 %.
8. 8. Düsenanordnung nach Ausführungsform 7, wobei die Querschnittsfläche des zweiten Querschnittbereichs größer ist als die Querschnittsfläche des ersten Querschnittbereichs.
9. 9. Düsenanordnung nach einer der Ausführungsformen 1 bis 8, wobei die Düsenanordnung mehrteilig ausgebildet ist mit einem ersten Teil, in dessen Oberfläche eine erste Vertiefung eingebracht ist, und mit einem zweiten Teil, in dessen Oberfläche eine zweite Vertiefung eingebracht ist, wobei der erste und der zweite Teil derart aneinander anliegen, dass die erste und die zweite Vertiefung einander gegenüberliegen und den Kanal bilden.
10. 10. Vorrichtung zur Erzeugung eines atmosphärischen Plasmastrahls mit einem Entladungsraum, wobei die Vorrichtung dazu eingerichtet ist, in dem Entladungsraum einen atmosphärischen Plasmastrahl zu erzeugen, und wobei eine Düsenanordnung nach einer der Ausführungsformen 1 bis 9 derart an den Entladungsraum angeschlossen ist, dass ein im Entladungsraum erzeugter Plasmastrahl in den Einlass der Düsenanordnung eingeleitet wird.
11. 11. Vorrichtung nach Ausführungsform 10, wobei die Vorrichtung dazu eingerichtet ist, einen atmosphärischen Plasmastrahl mittels einer bogenartigen Entladung in einem Arbeitsgas zu erzeugen, wobei die bogenartige Entladung durch Anlegen einer hochfrequenten Hochspannung zwischen Elektroden erzeugbar ist.
12. 12. Verwendung einer Vorrichtung nach Ausführungsform 10 oder 11 zur Plasmabehandlung eines Materials, vorzugsweise eines Stoffs oder einer Folie, insbesondere einer Kunststofffolie oder einer Metallfolie.
13. 13. Verwendung nach Ausführungsform 12, wobei die Vorrichtung zur Plasmabehandlung eines Vliesstoffs verwendet wird, insbesondere für die oder bei der Herstellung von Windeln, Binden oder Auflagen.
14. 14. Verfahren zur Plasmabehandlung eines Materials, vorzugsweise eines Stoffs, insbesondere eines Vliesstoffs, oder einer Folie, insbesondere einer Kunststofffolie oder einer Metallfolie, unter Verwendung einer Vorrichtung nach Ausführungsform 10 oder 11, bei dem mit der Vorrichtung ein atmosphärischer Plasmastrahl erzeugt wird, so dass der Plasmastrahl in Form mehrerer Teilstrahlen aus den Düsenöffnungen in der Kanalwandung austritt, und bei dem eine Oberfläche eines Materials, vorzugsweise eines Stoffs oder einer Folie, insbesondere einer Kunststofffolie oder einer Metallfolie, mit den Teilstrahlen des Plasmastrahls beaufschlagt wird.
15. 15. Verfahren nach Ausführungsform 14, wobei das Material, insbesondere der Stoff oder die Folie, bahnförmig ist und an den Düsenöffnungen der Vorrichtung vorbei transportiert wird.
16. 16. Verfahren nach Ausführungsform 14 oder 15, wobei das Material, insbesondere der Stoff oder die Folie, im Atmosphärendruckbereich mit den Teilstrahlen des Plasmastrahls beaufschlagt wird.
17. 17. Plasmabehandelter Vliesstoff, insbesondere ADL, hergestellt durch ein Verfahren mit folgenden Schritten:
    • Bereitstellen eines Vliesstoffs,
    • Plasmabehandeln des Vliesstoffs mit einem Verfahren nach einer der Ausführungsformen 14 bis 16.
18. 18. Hygieneartikel zur Aufnahme von Flüssigkeiten, insbesondere Binde oder Windel, aufweisend eine Lage aus plasmabehandeltem Vliesstoff nach Ausführungsform 17.

Further embodiments 1 to 9 of the nozzle arrangement, embodiments 10 and 11 of the device, embodiments 12 and 13 of the use, embodiments 14 to 16 of the method, embodiment 17 of the plasma-treated nonwoven and embodiment 18 of the hygiene article are described below.

1. 1. Nozzle arrangement for a device for generating an atmospheric plasma jet with an inlet through which an atmospheric plasma jet can be introduced into the nozzle arrangement, and with a channel which is connected to the inlet so that a plasma jet introduced through the inlet into the nozzle arrangement is passed through the channel, wherein a plurality of nozzle openings are provided in the channel wall along the channel, through which a plasma jet guided through the channel can exit the nozzle arrangement.
2. 2. The nozzle arrangement according to embodiment 1, wherein the channel has a straight section, and the nozzle openings are arranged in the channel wall in the direction of extension of the channel.
3. 3. Nozzle arrangement according to embodiment 1 or 2, the channel being connected to the inlet on both sides, so that a plasma jet introduced into the nozzle arrangement through the inlet is guided into the channel from both sides.
4. 4. Nozzle arrangement according to one of the embodiments 1 to 3, the diameter of the nozzle openings in the duct wall corresponding to a maximum of a quarter of the duct diameter.
5. 5. Nozzle arrangement according to one of the embodiments 1 to 4, wherein the cross section of the channel widens with increasing distance from the inlet.
6. 6. Nozzle arrangement according to one of the embodiments 1 to 5, wherein the nozzle arrangement is formed in several parts with a nozzle element that includes the channel with the nozzle openings, and with a distributor element that includes a distributor channel through which a plasma jet introduced through the inlet is introduced or is directed to the canal on both sides.
7. 7. Nozzle arrangement according to one of embodiments 1 to 6, wherein the cross section of the channel in the region of a nozzle opening is shaped in such a way that a fictitious central plane, which is in the middle between a fictitious first tangent plane of the cross section through the nozzle opening and one of these opposite and to the fictitious second tangent plane of the cross-section runs parallel to the first tangent plane, divides the cross-section into a first cross-sectional area at the nozzle opening and a second cross-sectional area opposite the nozzle opening, and wherein the cross-sectional area of the first cross-sectional area differs from the cross-sectional area of the second cross-sectional area, preferably by at least 5%, in particular by at least 10%.
8. 8. The nozzle arrangement according to embodiment 7, wherein the cross-sectional area of the second cross-sectional area is greater than the cross-sectional area of the first cross-sectional area.
9. 9. Nozzle arrangement according to one of embodiments 1 to 8, wherein the nozzle arrangement is designed in several parts with a first part, in the surface of which a first recess is made, and with a second part, in the surface of which a second recess is made, the first and the second part abut against one another in such a way that the first and second indentations are opposite one another and form the channel.
10. 10. A device for generating an atmospheric plasma jet with a discharge space, the device being designed to generate an atmospheric plasma jet in the discharge space, and wherein a nozzle arrangement according to one of the embodiments 1 to 9 is connected to the discharge space in such a way that one in the discharge space generated plasma jet is introduced into the inlet of the nozzle arrangement.
11. 11. The device according to embodiment 10, wherein the device is set up to generate an atmospheric plasma jet by means of an arc-like discharge in a working gas, the arc-like discharge being able to be generated by applying a high-frequency high voltage between electrodes.
12. 12. Use of a device according to embodiment 10 or 11 for the plasma treatment of a material, preferably a substance or a film, in particular a plastic film or a metal film.
13. 13. Use according to embodiment 12, wherein the device is used for plasma treatment of a nonwoven fabric, in particular for or during the production of diapers, sanitary towels or covers.
14. 14. A method for plasma treatment of a material, preferably a substance, in particular a nonwoven fabric, or a film, in particular a plastic film or a metal foil, using a device according to embodiment 10 or 11, in which an atmospheric plasma jet is generated with the device so that the plasma jet emerges in the form of several partial jets from the nozzle openings in the duct wall, and in which a surface of a material, preferably a substance or a film, in particular a plastic film or a metal foil, is exposed to the partial jets of the plasma jet.
15. 15. The method according to embodiment 14, wherein the material, in particular the fabric or the film, is web-shaped and is transported past the nozzle openings of the device.
16. 16. The method according to embodiment 14 or 15, wherein the material, in particular the substance or the film, is exposed to the partial jets of the plasma jet in the atmospheric pressure range.
17. 17. Plasma-treated non-woven fabric, in particular ADL, produced by a process with the following steps:
    • Providing a nonwoven fabric,
    • Plasma treatment of the nonwoven fabric using a method according to one of embodiments 14 to 16.
18. 18. Hygiene article for absorbing liquids, in particular a bandage or diaper, having a layer of plasma-treated nonwoven according to embodiment 17.

Further features and advantages of the nozzle arrangement, the device, the use, the method, the nonwoven fabric and the hygiene article emerge from the following description of various exemplary embodiments, reference being made to the accompanying drawings.

Fig. 1

eine Vorrichtung zur Erzeugung eines atmosphärischen Plasmastrahls,

Fig. 2

ein Ausführungsbeispiel der erfindungsgemäßen Düsenanordnung sowie ein Ausführungsbeispiel der erfindungsgemäßen Vorrichtung zur Erzeugung eines atmosphärischen Plasmastrahls in Explosionsdarstellung,

Fig. 3

das Ausführungsbeispiel der Düsenanordnung und das Ausführungsbeispiel der Vorrichtung aus Fig. 2 in Schnittdarstellung,

Fig. 4

ein alternatives Ausführungsbeispiel der Düsenanordnung und der Vorrichtung in Schnittdarstellung,

Fig. 5

ein weiteres alternatives Ausführungsbeispiel der Düsenanordnung und der Vorrichtung in Schnittdarstellung,

Fig. 6

ein Ausführungsbeispiel der erfindungsgemäßen Verwendung und des erfindungsgemäßen Verfahrens,

Fig. 7

eine Fotografie eines unbehandelten Vliesstoffes,

Fig. 8

eine Fotografie eines plasmabehandelten Vliesstoffes als Ausführungsbeispiel des erfindungsgemäßen plasmabehandelten Vliesstoffs,

Fig. 9a-b

ein Ausführungsbeispiel des erfindungsgemäßen Hygieneartikels,

Fig. 10

ein weiteres Ausführungsbeispiel der erfindungsgemäßen Düsenanordnung und der erfindungsgemäßen Vorrichtung,

Fig. 11

ein weiteres Ausführungsbeispiel der erfindungsgemäßen Düsenanordnung und der erfindungsgemäßen Vorrichtung,

Fig. 12

ein weiteres Ausführungsbeispiel der erfindungsgemäßen Düsenanordnung und der erfindungsgemäßen Vorrichtung,

Fig. 13a-c

Kanalquerschnitte weiterer Ausführungsbeispiele der erfindungsgemäßen Düsenanordnung,

Fig. 14a-c

Fotografien von Versuchen an verschiedenen Düsenanordnungen und

Fig. 15a-c

Kanalquerschnitte der Düsenanordnungen aus den Versuchen.

Show in the drawing

Fig. 1

a device for generating an atmospheric plasma jet,

Fig. 2

an embodiment of the nozzle arrangement according to the invention and an embodiment of the device according to the invention for generating an atmospheric plasma jet in an exploded view,

Fig. 3

the embodiment of the nozzle arrangement and the embodiment of the device Fig. 2 in sectional view,

Fig. 4

an alternative embodiment of the nozzle arrangement and the device in a sectional view,

Fig. 5

a further alternative embodiment of the nozzle arrangement and the device in a sectional view,

Fig. 6

an embodiment of the use according to the invention and the method according to the invention,

Fig. 7

a photograph of an untreated nonwoven fabric,

Fig. 8

a photograph of a plasma-treated nonwoven fabric as an embodiment of the plasma-treated nonwoven fabric according to the invention,

Figures 9a-b

an embodiment of the hygiene article according to the invention,

Fig. 10

another embodiment of the nozzle arrangement according to the invention and the device according to the invention,

Fig. 11

another embodiment of the nozzle arrangement according to the invention and the device according to the invention,

Fig. 12

another embodiment of the nozzle arrangement according to the invention and the device according to the invention,

Figures 13a-c

Channel cross-sections of further exemplary embodiments of the nozzle arrangement according to the invention,

Figures 14a-c

Photographs of experiments on different nozzle arrangements and

Figures 15a-c

Channel cross-sections of the nozzle arrangements from the experiments.

In the following, the structure and the mode of operation of a device for generating an atmospheric plasma jet are first described.

The device 2 has a tubular housing 4 in the form of a nozzle tube made of metal. The nozzle tube 4 has at one end a conical taper 6 on which an exchangeable nozzle head 8 is mounted, the outlet of which forms a nozzle opening 10 from which the plasma jet 12 emerges during operation.

At the end opposite the nozzle opening 10, the nozzle tube 4 is connected to a working gas feed line 14. The working gas supply line 14 is connected to a pressurized working gas source (not shown) with a variable throughput. During operation, a working gas 16 is introduced from the working gas source through the working gas feed line 14 into the nozzle tube 4.

In the nozzle tube 4, a swirl device 18 with a ring of bores 20 inclined in the circumferential direction is also provided, through which the working gas 16 introduced into the nozzle tube 4 during operation is swirled.

The downstream part of the nozzle pipe 4 is therefore traversed by the working gas 16 in the form of a vortex 22, the core of which runs on the longitudinal axis of the nozzle pipe 4.

In the nozzle tube 4, an inner electrode 24 is also arranged in the center, which extends in the nozzle tube 4 coaxially in the direction of the nozzle opening 10. The inner electrode 24 is electrically connected to the swirl device 18. The swirl device 18 is electrically insulated from the nozzle tube 4 by a ceramic tube 26. A high-frequency high voltage, which is generated by a transformer 30, is applied to the inner electrode 24 via a high-frequency line 28. The nozzle pipe 4 is grounded via a grounding line 32. The applied voltage causes a high-frequency discharge in the form of an arc 34 between the Inner electrode 24 and the nozzle tube 4 generated. This area in the nozzle tube 4 thus represents a discharge space 36 of the device 2.

The terms "arc", "arc discharge" and "arc-like discharge" are used herein as phenomenological descriptions of the discharge, since the discharge occurs in the form of an arc. The term “arc” is also used elsewhere as a form of discharge in the case of direct voltage discharges with essentially constant voltage values. In the present case, however, it is a high-frequency discharge in the form of an arc, that is to say a high-frequency arc-like discharge.

Due to the swirling flow of the working gas, this arc 34 is channeled in the vortex core in the area of the axis of the nozzle tube 4, so that it only branches in the area of the taper 6 to the wall of the nozzle tube 4.

The working gas 16, which rotates in the area of the vortex core and thus in the immediate vicinity of the arc 34 at high flow speed, comes into intimate contact with the arc 34 and is thereby partially converted into the plasma state, so that an atmospheric plasma jet 12 passes through the nozzle opening 10 exits from device 2.

Fig. 2 now shows an embodiment of the nozzle arrangement according to the invention and an embodiment of the device according to the invention for generating an atmospheric plasma jet in an exploded view. Fig. 3 shows the nozzle head and the device in sectional view.

The device 40 comprises the nozzle arrangement 42 and the device 2 Fig. 1 , whereby instead of the exchangeable nozzle head 8, a connection piece 44 of the nozzle arrangement 42 is connected to the nozzle tube 4. The connection piece 44 has a conically tapering inner channel 46 which forms the lower part of the discharge space 36 of the device 2. In operation comes from the lower Opening 48 of the connection piece 44, the plasma jet 12 from and into the other components of the nozzle arrangement 42. The lower opening 48 can accordingly be viewed as the inlet of the nozzle arrangement 42.

The nozzle arrangement 42 furthermore comprises a distributor element 50 composed of two parts 50a-b and a nozzle element 52. A groove 54 is made in the nozzle element 52, which when the nozzle arrangement 42 is assembled, as in FIG Fig. 3 shown forms a channel 56 having a first end 58 and a second end 60. A plurality of nozzle openings 62 are introduced next to one another along the channel in the channel wall of the channel 56.

The parts 50a-b of the distributor element 50 have respective grooves 64a-b which, in the assembled state, form a distributor channel 66. The distribution channel has a branch 68 and connects the inlet 48 to both the first end 58 and the second end 60 of the channel 56.

If a plasma jet 12 is generated during operation with the device 2, it passes through the inlet 48 on the connection piece 44 into the distribution channel 66 and is in this way guided to both ends 58, 60 of the channel 56 and through the channel 56, so that it emerges in the form of several partial jets 70 from the nozzle openings 62 from the nozzle arrangement 42. In this way, a curtain is created from several juxtaposed partial beams 70, the individual partial beams 70 having a reduced intensity compared to the plasma beam 12, with which, for example, a nonwoven material 72 guided past the nozzle openings 62 can be plasma treated without damaging it.

Because the plasma jet 12 is introduced into the channel 56 on both sides via the distributor channel 66, it is achieved that the individual partial jets 70 have a relatively similar intensity. Optionally, the intensity of the individual partial beams 70 can additionally be evened out further in that the channel has a cross section that widens slightly from both ends 58, 60 towards the center of the channel is formed, whereby an excessive pressure drop at greater distances from the inlet 48 is counteracted.

The nozzle arrangement 42 also has a cooling body 74 made of aluminum with cooling ribs 76 surrounding the remaining components, through which the heat load introduced into the nozzle arrangement 42 by the plasma jet 12 can be dissipated.

Fig. 4 shows an alternative embodiment of the nozzle arrangement and the device in a sectional illustration. The device 40 'and the nozzle arrangement 42' are essentially identical in construction to the device 40 and the nozzle arrangement 42. Identical parts are each provided with the same reference numerals.

The nozzle arrangement 42 ′ differs from the nozzle arrangement 42 only in that the channel 56 is connected to the inlet 48 in such a way that the plasma jet is guided into the channel 56 from one side. To this end, the manifold element 50 'and the nozzle element 52' are as in FIG Fig. 4 shown trained.

In order to counteract an excessive pressure drop in the channel 56 and to even out the intensities of the partial jets 70, the cross-section of the channel 56 can increase with increasing distance from the inlet 48 (ie in Fig. 4 from left to right) optionally widen slightly.

Fig. 5 shows an alternative embodiment of the nozzle arrangement and the device in a sectional illustration. The device 40 "and the nozzle arrangement 42" are essentially identical in construction to the device 40 'and the nozzle arrangement 42'. The same parts are provided with the same reference numerals.

The nozzle arrangement 42 ″ differs from the nozzle arrangement 42 ′ only in that an additional gas feed 57 is provided through which a gas 59 can be introduced into the channel 56 separately from the plasma jet. For this purpose the groove 54 ″ runs as in FIG Fig. 5 shown up to the edge of the nozzle element 52 ″ and in the heat sink 74 ″ an opening for introducing the gas 59 into the channel 56 is provided. By introducing the gas 59, in particular nitrogen, the plasma jet in the channel 56 can be additionally cooled, so that the partial jets 70 emerging from the nozzle openings 62 allow a very gentle treatment of nonwovens.

Fig. 6 shows an embodiment of the use according to the invention and the method according to the invention. The device 40 can in particular be used to treat sensitive nonwovens with plasma.

For this purpose, the web-shaped non-woven fabric 72 can be used as in FIG Fig. 3 - 5 shown past the nozzle openings of the device 40 (or alternatively also 40 'or 40 ") in order to treat the nonwoven fabric 72 over its entire length. The nozzle openings are as in FIG Fig. 4 illustrated is preferably arranged transversely to the transport direction of the nonwoven web 72, so that the nonwoven 72 can be treated with the device 40 over a certain width, optionally over the entire width or part of the width of the nonwoven web 72.

In order to further reduce the load on the nonwoven web 72 during the plasma treatment, the nonwoven web 72 is guided in front of and behind the treatment area 77 with the device 40 in each case over a roller 78a-b, which rotate at the same speed. In this way, tensile forces on the nonwoven web 72 in the treatment area 77 are reduced. To further reduce the tensile forces, a treatment table 79 in the form of an aluminum plate is provided, over which the nonwoven web 72 is guided in the treatment area 77. In the direction of transport behind the treatment area 77, suction openings 80 are provided in the treatment table 79, through which ozone or nitrogen oxides can be sucked off, which arise when nitrogen is preferably used as the working gas for the device 2 or 40.

Since the device 40 enables sensitive fabrics such as the nonwoven web 72 to be treated without damage even under atmospheric pressure, the device can be used as in FIG Fig. 6 shown to be operated without a vacuum chamber. In particular, inline operation, in particular within a continuous process section, is possible, since no inward and outward transfer processes are required.

Fig. 7 shows a photograph of an untreated nonwoven from the side. The nonwoven fabric consists of individual fibers intertwined with one another, in particular plastic fibers, which result in a relatively compact fabric. The nonwoven fabric shown has a thickness of approx. 1 mm.

Fig. 8 shows a photograph of the nonwoven from FIG Fig. 7 after dealing with the in Fig. 3 device 40 shown was plasma treated. Fig. 8 shows an embodiment of the plasma-treated nonwoven fabric according to the invention. After the plasma treatment, the nonwoven has a greatly increased thickness of approx. 5 mm and a correspondingly less compact structure with a lower density. It has been shown that this leads to an improvement in the capillarity of the nonwoven fabric, so that liquids are better guided through the fabric. Furthermore, the plasma treatment made the fibers hydrophilic so that the material can absorb liquids more quickly.

The Figures 9a-b now show an embodiment of a hygiene article according to the invention for holding liquids in plan view ( Figure 9a ) and on average ( Figure 9b ) along the in Figure 9a with "IXb" designated cutting plane. In the present case, the hygiene article 82 is a sanitary napkin, but a corresponding structure is also possible in the case of a diaper or pad.

The hygiene article 82 has a shaping outer layer 83, a superabsorbent layer 84 (so-called absorbent core), a distribution layer (ADL / AQL) 86 made of plasma-treated non-woven fabric, for example made of non-woven fabric 72 Fig. 4 , a receiving layer 88 made of nonwoven fabric which has been plasma-treated in sections and a Cotton layer 90 as a cover layer. The superabsorbent layer 84 can comprise, for example, liquid-absorbing powder, in particular made of superabsorbent polymers.

When used as intended, the cotton layer is in contact with the surface of the skin and makes the skin feel pleasant. The receiving fleece 88 arranged underneath is only plasma-treated in the middle 92, while the edges 94 are untreated. In this way, the receiving fleece 88 has hydrophilic properties in the middle 92, so that liquid is well guided into the distribution layer 86 located below. On the other hand, the absorbent fleece 88 has hydrophobic properties at the edges 94, which prevents liquid from escaping at the edges of the hygiene article 82. The targeted plasma treatment in the center 92 of the receiving fleece 88 can in particular replace the hydrophilization by applying surfactants used in the prior art and which is more complex in terms of process technology.

The distribution layer 86 arranged under the receiving fleece 88 distributes the liquid in the area, so that the liquid then reaches the absorbent core 84, which is distributed over a larger area. As a result of the plasma treatment of the absorbent fleece 88, the liquid can be taken up by the distributor layer 86 more quickly.

By using the plasma-treated nonwoven fabric 72 for the receiving nonwoven 88 and / or the distribution layer 86, the manufacturing costs of the hygiene article 82 can be reduced, since receiving or distribution layers with a short penetration time can also be achieved with cheaper nonwovens 72.

The Figures 10 and 11 show further exemplary embodiments and possible uses of the device described above.

In the Fig. 10 The device 100 shown has a structure similar to that of the device 40 Fig. 2 wherein the device 2 and the connection piece 44 are, however, positioned in the center of the nozzle arrangement 42 and the distributor element 50 of the nozzle arrangement 42 has a correspondingly adapted course of the distributor channel 66. Alternatively, the device 100 can also be similar to the device 40 ' Fig. 4 or like device 40 ″ Fig. 5 be trained.

The nozzle arrangement 42 can be rotated by means of a rotary drive 102 about an axis perpendicular to the direction of extension of the channel 56. In this way, the partial jets 70 emerging from the nozzle openings 62 can be swept over a larger surface area, so that the device 100 can be used for large-area plasma treatment 100. In particular, the device 100 can be used for the plasma treatment of a material, in particular a nonwoven material, or a plastic film.

Fig. 11 FIG. 11 shows an alternative device 110, which again has a similar structure to device 40 from FIG Fig. 2 The device 2 and the connection piece 44, however, are positioned laterally on the nozzle arrangement 42 and the distributor element 50 of the nozzle arrangement 42 has a correspondingly adapted course of the distributor channel 66. Alternatively, the device 110 can also be similar to the device 40 ′ Fig. 4 or like device 40 ″ Fig. 5 be trained.

The nozzle arrangement 42 can be rotated by means of a rotary drive 112 about an axis parallel to the direction of extent of the channel 56. The device 110 can also be used for the plasma treatment of a material, in particular a nonwoven material, or a plastic film.

Furthermore, the device 110 can also be used for other purposes. In particular, the partial jets 70 exiting from the nozzle openings 62 a tubular component can be exposed to plasma from the inside, for example in order to treat an inner wall of the tube with plasma.

Fig. 12 shows a further embodiment of the nozzle arrangement according to the invention and the device according to the invention. The device 40 ′ ″ and the nozzle arrangement 42 ′ ″ are essentially identical in construction to the device 40 ′ and the nozzle arrangement 42 ′ Fig. 4 . The same parts are provided with the same reference numerals.

The nozzle arrangement 42 '"differs from the nozzle arrangement 42' in that the nozzle element 52 '" has a first channel-shaped recess 120 and the distributor element 50' "has a second channel-shaped recess 122, the distributor element 50 '" and the nozzle element 52' " abut one another in such a way that the first and the second channel-shaped recesses 120 and 122 lie opposite one another and form the channel 56 '' '. This construction allows various cross-sectional shapes of the channel 56 ′ ″ to be produced in a simple manner by correspondingly shaping the depressions 120 and 122. The nozzle openings 62 extend from the first depression 120.

The first and second channel-shaped recesses 120, 122 can each have a semicircular cross-section with the same radius, for example, so that the channel 56 '' 'has a circular cross-section. The radius of the two semicircular cross-sections of the first and second recesses 120, 122 can, for example, decrease continuously in the direction of extent of the channel 56 '", so that a channel 56'" with a decreasing cross-section results. Such a cross-section of the channel 56 "'can be produced much more cheaply and easily than with the two recesses 120, 122 a channel in the solid material.

The Figures 13a-c show three further possible cross-sections 124 ', 124 "and 124'" of the channel 56 '"for further exemplary embodiments of the nozzle arrangement according to the invention. For the sake of clarity, the figures each show only the Section plane with no representation of the edges behind it. The nozzle arrangements each correspond to the nozzle arrangement 42 '"from Fig. 12 , wherein the first recess and the second recess and the channel 56 '"formed thereby each have one of the in the Figures 13a-c illustrated cross-sections 124 ', 124 "and 124'". The schematic cross-sectional representations in Figures 13a-c correspond to the in Fig. 12 with "XIII" designated section plane.

Figure 13a shows a first recess 120 'in the nozzle element 52'"and a second recess 122 'in the distributor element 50'" each with a semicircular cross section, the semicircle diameter of the second recess 122 'being greater than the semicircle diameter of the first recess 120'. This results in a cross section 124 'of the channel from two opposing semicircular disks.

Figure 13a also shows the fictitious first tangent plane 130 of the cross section 124 'through the nozzle opening 62 and the fictitious second tangent plane 132 opposite this and running parallel to it. The first tangent plane 132 runs through the mouth of the nozzle opening 62 into the channel and tangential to the recess 124 and to the Cross section 124 '. Tangential here means that the first tangent plane 124 touches the channel cross section 124 ', but does not intersect it.

In the middle between the fictitious first and second tangent planes 130 and 132, the fictitious center plane 134 is drawn, which divides the cross section 124 'into a first cross-sectional area 126' at the nozzle opening 62 and into a second cross-sectional area 128 'opposite the nozzle opening 62. Due to the different semicircular radii of the two depressions 120 'and 122', the cross-sectional area in the second cross-sectional area 128 'is larger than the cross-sectional area in the first cross-sectional area 126'.

Figure 13b also shows a first recess 120 ″ in the nozzle element 52 ′ ″ and a second recess 122 ″ in the distributor element 50 ″ ′, each with a semicircular cross-section, although in this exemplary embodiment the semicircle diameter of the first recess 120 "is larger than the semicircular diameter of the second recess 122". Furthermore, in Figure 13b the fictitious first and second tangent planes 130 and 132 as well as the fictitious central plane 134, which divides the cross-section 124 "into a first cross-sectional area 126" at the nozzle opening 62 and into a second cross-sectional area 128 "opposite the nozzle opening 62, are also drawn in. The different semicircular radii of the In both depressions 120 "and 122", the cross-sectional area in the second cross-sectional area 128 "is smaller than the cross-sectional area in the first cross-sectional area 128".

Figure 13c shows a first recess 120 '"in the nozzle element 52"' with a triangular cross-section and a second recess 122 '"in the distributor element 50'" with a semicircular cross-section, so that the in Figure 13c shown cross section 124 '"results. Furthermore, in Figure 13c the fictitious first and second tangent plane 130 and 123 as well as the fictitious central plane 134 are also drawn in, which divides the cross-section 124 '"into a first cross-sectional area 126'" at the nozzle opening 62 and into a second cross-sectional area 128 '"opposite the nozzle opening 62 Cross-section 124 '", the cross-sectional area of the second cross-sectional area 126'" is greater than the cross-sectional area in the first cross-sectional area 128 "'.

The position of the fictitious central plane 134 is fundamentally independent of the contact surface between nozzle element 52 '"and distributor element 50"'. The center plane 134 can thus coincide with the contact surface (cf. Figure 13c ), but does not have to be (cf. Figures 13a-b ).

Tests have shown that an asymmetrical cross section of the channel 56 ''', as for example in the Figures 13a-c shown, a more even distribution of the plasma power to the partial jets emerging from the individual nozzle openings 62 can be achieved. Particularly good results were achieved when the cross-sectional area of the second cross-sectional area with respect to the nozzle opening 62 was larger than the cross-sectional area of the first cross-sectional area. That means they are in the Figures 13a and 13c Embodiments shown are particularly preferred.

Tests have been carried out showing the advantages of an asymmetrical channel cross-section. For this purpose a device corresponding to the device 40 '"was selected Fig. 12 operated with different cross-sections of the channel 56 '" Figures 14a-c show photographs of the partial jets emerging from the nozzle openings 62 of the respective nozzle arrangement. Figures 15a-c shows the associated channel cross-sections 140, 142, 144 of the nozzle arrangements used in each case for the tests.

The nozzle arrangements are in the Figures 14a-c each arranged at the top; the direction of flow of the partial jets therefore runs from top to bottom. The position of the plasma nozzle is as in Fig. 12 on the left. The photographs have been inverted for better visibility. Figures 14a-c actually show the photographic negatives, so that the actually glowing partial rays are shown dark and the dark surroundings are shown light.

Figure 14a shows the photograph of the partial jets from a nozzle arrangement with a round channel cross section 140 accordingly Figure 15a . The first and the second recess each have a semicircular shape with a semicircle radius r ₁ , r ₂ of 2 mm each.

Figure 14b shows the photograph of the partial jets from a nozzle arrangement with an asymmetrical channel cross-section 142, accordingly Figure 15b . The first and second indentations each have semicircular shapes, but with a different semicircle radius, where r ₁ = 1.5 mm and r ₂ = 2.55 mm.

Figure 14c shows the photograph of the partial jets from a nozzle arrangement with an asymmetrical channel cross section 144 accordingly Figure 15c . The first and second indentations each have semicircular shapes, where r ₁ = 2.55 mm and r ₂ = 2 mm.

A comparison of the photographs in Figures 14a-c shows that the intensity of the plasma jet for the asymmetrical channel cross-sections 142 and 144 (cf. Figures 14b-c ) is better distributed over the partial jets emerging from the nozzle openings 62 than in the case of the symmetrical channel cross section 140 (cf. Figure 14a ). This is particularly evident in the lengths of the visibly luminous areas of the partial beams (in Figures 14a-c dark) in Figure 14a is quite different. The visible areas of the partial beams are in Figure 14a significantly shorter on the left (ie near the nozzle) than on the right.

A particularly even distribution of the plasma jet among the partial jets was achieved with the channel cross section 142 (cf. Figure 14b ) achieved in which the second cross-sectional area has a larger cross-sectional area than the first cross-sectional area.

Claims (17)

1. Nozzle assembly (42, 42', 42", 42"') for a device (40, 40', 40", 40"', 100, 110) for generating an atmospheric plasma jet (12),

   - comprising an inlet (48) through which an atmospheric plasma jet (12) can be introduced into the nozzle assembly (42, 42', 42", 42'"), and

   - comprising a channel (56, 56"') which is connected to the inlet (48) such that a plasma jet (12) introduced into the nozzle assembly (42, 42', 42" 42"') through the inlet (48) is conducted through the channel (56, 56'"),

   - wherein multiple nozzle openings (62) are provided in the channel wall along the channel (56, 56"'), through which a plasma jet (12) which is conducted through the channel (56, 56'") can exit the nozzle assembly (42, 42', 42", 42"'), characterised in that

   - the cross section (124', 124", 124"', 140, 142, 144) of the channel (56, 56'") in the region of a nozzle opening (62) is shaped in such a way that a virtual medial plane (134), which runs in the middle between a virtual first tangent plane (130) of the cross section through the nozzle opening (62) and a virtual second tangent plane (132) of the cross section opposite thereto and parallel to the first tangent plane (130), divides the cross section into a first cross-sectional area (126', 126", 126"') at the nozzle opening (62) and a second cross-sectional area (128', 128", 128"') opposite to the nozzle opening (62), and

   - in that the cross-sectional surface of the first cross-sectional area (126', 126", 126"') differs from the cross-sectional surface of the second cross-sectional area (128', 128", 128"'), preferably by at least 5%, in particular by at least 10%.
2. Nozzle assembly according to claim 1,
   characterised in that the channel (56, 56'") has a straight section, and the nozzle openings (62) are arranged in the channel wall in the extension direction of the channel (56, 56"').
3. Nozzle assembly according to claim 1 or 2,
   characterised in that the channel (56, 56"') is connected on both sides to the inlet (48), such that a plasma jet (12) introduced into the nozzle assembly (42) through the inlet (48) is conducted into the channel (56, 56"') from both sides.
4. Nozzle assembly according to any one of claims 1 to 3,
   characterised in that the diameter of the nozzle openings (62) in the channel walling is at most a quarter of the channel diameter.
5. Nozzle assembly according to any one of claims 1 to 4,
   characterised in that the cross section of the channel (56, 56"') widens as the distance from the inlet (48) increases.
6. Nozzle assembly according to any one of claims 1 to 5,
   characterised in that the nozzle assembly (42, 42', 42", 42'") is formed in several parts with a nozzle element (52, 52', 52", 52"'), which comprises the channel (56, 56'") with the nozzle openings (62), and with a distributor element (50, 50', 50"'), which comprises a distribution channel (66) through which a plasma jet (12) introduced through the inlet (48) is conducted to the channel (56, 56'") on one or both sides.
7. Nozzle assembly according to any one of claims 1 to 6,
   characterised in that the cross-sectional surface of the second cross-sectional area (128', 128", 128'") is greater than the cross-sectional surface of the first cross-sectional area (126', 126", 126'").
8. Nozzle assembly according to any one of claims 1 to 7,
   characterised in that the nozzle assembly (42, 42', 42", 42'") is formed in several parts with a first part (52, 52', 52", 52"'), in the surface of which a first recess (120', 120", 120"') is introduced, and with a second part (50, 50', 50'"), in the surface of which a second recess (122', 122", 122'") is introduced, wherein the first and the second part adjoin each other such that the first and second recess face each other and form the channel (56, 56', 56", 56"').
9. Device (40, 40', 40", 40'", 100, 110) for generating an atmospheric plasma jet (12),

   - comprising a discharge space (36),

   - wherein the device (40, 40', 40", 40"', 100, 110) is configured to generate an atmospheric plasma jet (12) in the discharge space (36),
   characterised in that

   - a nozzle assembly (42,42', 42", 42'") according to any one of claims 1 to 8 is connected to the discharge space (36) in such a way that a plasma jet (12) generated in the discharge space (36) is introduced into the inlet (48) of the nozzle assembly (42, 42', 42", 42"').
10. Device according to claim 9,
    characterised in that the device (40, 40', 40", 40'", 100,110) is configured to generate an atmospheric plasma jet (12) by means of an arc-like discharge (34) in a working gas (16), wherein the arc-like discharge (34) can be generated by applying a high-frequency high voltage between electrodes (24, 4).
11. Use of a device (40, 40', 40", 40'", 100, 110) according to claim 9 or 10 for the plasma treatment of a material, in particular a fabric (72) or a film, in particular a plastic film or a metal film.
12. Use according to claim 11,
    characterised in that the device (40, 40', 40", 40"', 100, 110) is used for the plasma treatment of a nonwoven fabric (72), in particular for or in the manufacture of diapers, sanitary napkins or pads.
13. Method for the plasma treatment of a material, preferably a fabric, in particular a nonwoven fabric (72), or a film, in particular a plastic film or a metal film, using a device (40, 40', 40", 40"', 100, 110) according to claim 9 or 10,

    - in which an atmospheric plasma jet (12) is produced with the device (40, 40', 40", 40"', 100, 110) so that the plasma jet (12) emerges from the nozzle openings (62) in the channel walling in the form of a plurality of partial jets (70), and

    - in which a surface of a material, preferably a fabric (72) or a film, in particular a plastic film or a metal film, is impinged with the partial jets (70) of the plasma jet (12).
14. Method according to claim 13,
    characterised in that the material, in particular the fabric (72) or the film, is a web-type material and is transported past the nozzle openings (62) of the device (40, 40', 40", 40'", 100, 110).
15. Method according to claim 13 or 14,
    characterised in that the material, in particular the fabric (72) or the film, is impinged with the partial jets (70) of the plasma jet (12) under atmospheric pressure.
16. Plasma-treated nonwoven fabric (72), in particular ADL, produced by a method comprising the following steps:

    - providing a nonwoven fabric (72),

    - plasma treating the nonwoven fabric (72) by a method according to any one of claims 13 to 15.
17. Sanitary product (82) for absorbing liquids, in particular a sanitary napkin or diaper, comprising a layer (86, 88) of plasma-treated nonwoven fabric (72) according to claim 16.

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