ES2976781T3 - Procedure and device for manufacturing a non-woven fabric from fibers - Google Patents

Abstract

Method for producing a nonwoven fabric from fibers. The continuous filaments of thermoplastic material are produced by at least one meltblown spinneret. In addition, the short pulp fibers are produced by at least one defibration device. In the defibration device, at least one short fiber air stream is generated from the short pulp fibers, which is guided through and exits an outlet channel and flows with an initial volumetric flow V1 and a flow direction S1 in the direction of an air. - Permeable depositing screen belt. The continuous filaments flow from at least one meltblown spinneret as a filament air stream with an initial volumetric flow V2 in the direction of the short fiber air stream. The filament air stream and the short-fibre air stream meet above the depositing screen belt in a contact zone and are deposited as a mixture of continuous filament short fibres in a deposit area on the depositing screen belt to form the nonwoven fabric or nonwoven web. In the deposit zone of the fibres or the continuous mixture of filaments and short fibres, air or process air is drawn in from below through the depositing screen belt at a volume flow rate V4. The volume flow rate V4 is greater than the sum of the volume flow rates V1 and V2. (Automatic translation with Google Translate, not legally binding)

Description

DESCRIPTION

Procedure and device for manufacturing a non-woven fabric from fibers

The invention relates to a method for producing a nonwoven material from fibres, wherein endless filaments of thermoplastic plastic are produced by means of at least one meltblown spinning nozzle, preferably by means of at least two meltblown spinning nozzles, wherein short pulp fibres are further produced by means of at least one defibre-making device, wherein at least one air stream and short fibres are produced from the short pulp fibres in the defibre-making device, wherein the endless filaments flow from the at least one meltblown spinning nozzle as an air stream and filaments, and wherein the endless filaments and the short pulp fibres are deposited in a depositing area on a depositing screen belt converted into nonwoven material or nonwoven tape. The invention also relates to a device for producing a nonwoven fabric from fibres. Within the scope of the invention, the term fibres refers to both endless filaments and short fibres. Endless filaments differ from short fibres by their almost infinite length, the latter having considerably shorter lengths of, for example, 0.1 mm to 60 mm. Using the method according to the invention or the device according to the invention, a nonwoven material can be produced which contains at least endless filaments or meltblown endless filaments and short fibres or short pulp fibres.

Methods and devices of the type mentioned at the outset are basically known from practice and from the prior art in various embodiments. US 2012/0053547 A1 describes a method and device for producing a nonwoven fabric from fibers. The nonwoven material may comprise short pulp fibers. US 2006/0004336 A1 also discloses a method and device for producing a nonwoven fabric from polymer fibers, the nonwoven material may additionally contain cellulose fibers.

Nonwovens containing short pulp fibres are characterised by a very high liquid absorption capacity. These nonwovens based on short pulp fibres are used, for example, for liquid absorption cloths such as rags or cleaning cloths. The liquid can in particular be water or aqueous liquids. However, in the production of nonwovens containing short pulp fibres, it has been shown that there is a conflict of objectives between a high liquid absorption capacity and a sufficient stability or strength of the nonwoven fabric. In order to mechanically stabilise or stabilise nonwoven fabrics, the use of mixtures of endless filaments and short pulp fibres for the nonwoven fabrics is known. In this respect, the endless filaments are essentially responsible for the strength or stability of the nonwoven fabric, while the short pulp fibres ensure the liquid absorption capacity of the resulting product. However, there is still a need for improvement in these nonwovens made from endless filaments and short pulp fibres with regard to an optimum balance between liquid absorption capacity and mechanical strength. Furthermore, it has been shown that, with the procedures known from practice, the uniformity of the distribution of the endless filaments and short pulp fibres in the end product leaves much to be desired. There is also a need for improvement in this respect, since, with a very uniform distribution of endless filaments and short pulp fibres, a satisfactory balance between mechanical strength and liquid absorption capacity of the nonwoven material could be achieved even with a relatively small proportion of endless filaments.

In accordance with the above, the invention is based on the technical problem of indicating a process of the type mentioned at the beginning with which a nonwoven fabric can be produced from endless filaments or meltblown endless filaments and short fibers or short pulp fibers, which is characterized by an optimal balance between strength or stability and liquid absorption capacity and, in particular, has a high uniformity in the distribution of endless filaments and short pulp fibers. Furthermore, the invention is based on the technical problem of indicating a device for producing such a nonwoven material.

In order to solve this technical problem, the invention teaches a process for producing a nonwoven material from fibres, wherein endless filaments of thermoplastic plastic are produced by means of at least one meltblown spinning nozzle, preferably by means of at least two meltblown spinning nozzles, wherein short pulp fibres are further produced by means of at least one defibre separator, wherein at least one flow of air and short fibres is produced in the defibre separator from the short pulp fibres, which flows out of an outlet channel and flows with an initial volume flow rate V1 and a flow direction S1 in the direction of an air-permeable depositing screen belt,

the endless filaments flowing from the at least one meltblown spinning nozzle as a flow of air and filaments with an initial volumetric flow rate V2 in the direction of the flow of air and short fibers,

the air and filament stream and the air and short fiber stream being grouped above the depositing screen belt in a contact zone and being deposited as a mixture of endless filaments and short fibers in a deposit zone on the depositing screen belt as nonwoven or nonwoven belt,

air or process air is drawn into the depositing area of the fibres or the mixture of short fibres and endless filaments from below through the depositing sieve belt at a volumetric flow rate V4, the volumetric flow rate V4 being greater than the sum of the volumetric flow rates V1 and V2.

In the process according to the invention, molten plastic filaments are produced by the meltblown spinning nozzle or the meltblown spinning nozzles and extruded into a fast blowing air flow. The blown air advantageously also exits the meltblown spinning nozzle and is preferably warm or hot blown air. From the at least one meltblown spinning nozzle or the meltblown spinning nozzles, filament streams of the produced endless filaments and the blown air flow into the air flow and short fibers. The design of the meltblown spinning nozzle or the meltblown spinning nozzles, in particular with regard to the outlet of the molten plastic filaments and the blown air, will be explained in more detail below.

In accordance with the invention, endless filaments are produced from thermoplastic plastic. In the context of the process according to the invention, it is preferred that endless filaments are produced from at least one polyolefin. It is recommended that at least one polyolefin is polypropylene and/or polyethylene, preferably polypropylene. In principle, the endless filaments can also be produced from other thermoplastic plastics such as polyesters, for example polyethylene terephthalate or polyamide, and from mixtures of the abovementioned thermoplastic plastics. It is recommended that the endless filaments or meltblown endless filaments have an average filament diameter in the range of 0.2 to 15 µm, preferably 0.5 to 12 µm, preferably 0.5 to 10 µm.

In the context of the invention, the term "pulp" means in particular a fibrous material based on pulp or cellulose. In the process according to the invention, solid pulp is expediently used. The term "solid pulp" is understood in particular to mean a dry material based on pulp or cellulose. In the context of the invention, a solid pulp web is particularly preferably used and is defibered into short pulp fibers by means of at least one defibering device. The pulp used in the process according to the invention is preferably conditioned. The short pulp fibers produced in at least one defibering device expediently have a length or average length of 0.05 to 5 mm, preferably 0.1 to 4 mm, particularly preferably 0.1 to 3 mm.

In a preferred embodiment of the invention, the defibering plant is a sawmill. According to the invention, a flow of air and short fibers is generated in the defibering plant from the short pulp fibers, which is guided through an outlet channel and leaves it with an initial volume flow rate V1 and flows in a flow direction S1 in the direction of an air-permeable depositing screen belt. The outlet channel is expediently part of the defibering plant or is connected to the defibering plant. In the context of the invention, the initial volume flow rate V1 is understood to mean the volume flow rate of the mixture of short fibers and air directly or immediately after leaving the outlet channel.

According to a preferred embodiment of the invention, the air-permeable deposit screen belt is a continuously moving, air-permeable deposit screen belt, in particular an endlessly circulating deposit screen belt.

According to the invention, the endless filaments produced flow from the at least one meltblown spinning nozzle as a flow of air and filaments with an initial volume flow rate V2 in the direction of the flow of air and short fibers. In this respect, the initial volume flow rate V2 is understood in particular to mean the volume flow rate of the air and filament flow which is located directly or immediately below the meltblown spinning nozzle after the endless filaments have been stressed by the blown air.

According to the invention, air or process air is drawn in through the depositing sieve belt at least in the depositing area of the fibres or the mixture of endless filaments and short fibres. For this purpose, at least one suction device or a suction fan is conveniently arranged below the depositing sieve belt, in particular below the depositing area. According to the invention, the volume flow rate V4 drawn in through the depositing sieve belt is greater than the sum of the volume flow rates V1 and V2, so that the following applies: V4 > (V1 V2). According to a particularly preferred embodiment of the method according to the invention, the volume flow rate V4 corresponds to between 1.05 and 30 times, preferably between 5 and 25 times, preferably between 10 and 20 times the sum of the volume flow rates V1 and V2.

In a particularly preferred embodiment of the invention, at least two meltblown spinning nozzles, in particular two meltblown spinning nozzles, are present. Particularly preferably, the endless filaments flow from the second meltblown spinning nozzle as a second air and filament flow with an initial volume flow rate V3 into the air and short fiber flow. The initial volume flow rate V3 is understood in particular to mean the volume flow rate of the air and filament flow which is located directly or immediately below the meltblown spinning nozzle or the second meltblown spinning nozzle after the endless filaments have been stressed by the blown air. It is particularly preferred that the volume flow rate V4 is thus greater than the sum of the volume flow rates V1, V2 and V3, so that in particular the following applies: V4 > (V1 V2 V3). According to a particularly preferred embodiment of the process according to the invention, the volumetric flow rate V4 corresponds to between 1.05 and 30 times, preferably between 5 and 25 times, preferably between 10 and 20 times the sum of the volumetric flow rates V1, V2 and V3.

It has been proven effective for the air and filament flow to flow in the transport direction F of the depositing screen belt before the air and short fiber flow and for the second air and filament flow to flow preferentially in the transport direction F of the depositing screen belt behind the air and short fiber flow.

The invention provides that the air and filament stream flows at least in regions or sections at an angle a1 to the flow direction S1 of the air and short fiber stream with respect to its flow direction S3. The second air and filament stream flows advantageously at least in regions or sections at an angle a2 to the flow direction S1 of the air and short fiber stream with respect to its flow direction S3. A particularly preferred embodiment of the invention is characterized in that the angle a1 and/or the angle a2 is greater than 10°, particularly preferably greater than 20° and very particularly preferably greater than 25°. Within the scope of the invention, both air and filament streams thus flow towards the air and short fiber stream. The fact that the air-filament flow or the air-filament flows flow with respect to their flow direction S2 or S3 at an angle a i or a2 to the flow direction S i of the air-filament flow means in particular for the purposes of the invention that the flow vector of the air-filament flows runs at least in regions or sections at an angle a i or a2 to the flow direction S i or to the flow vector of the air-filament flow. For the purposes of the invention, the terms flow direction and flow vector refer in particular to the mean flow directions or flow vectors of the respective flows.

In the context of the invention, it is particularly preferred that the at least one air stream and filaments, in particular the air streams and filaments, flow with respect to their flow direction S2 or S3, at least in the contact zone or shortly before it at the angle a i or a2 with respect to the flow direction S i of the air stream and short fibers. Thus, the angles a i and a2 relate in particular to the inclination angles at which the air streams and filaments in the contact zone meet the air stream and short fibers. In a preferred embodiment of the invention, the at least one air and filament stream, in particular both air and filament streams, flow relative to their flow direction over the entire flow path - in particular in a straight line or substantially in a straight line - from the respective meltblown spinning nozzle to the contact zone at the angle a i or a2 to the flow direction Si of the air and short fiber stream. In this regard, it is particularly preferred that the at least one air and filament stream or the air and filament streams and/or the air and short fiber stream flow from the meltblown spinning nozzles or from the outlet channel to the contact zone without the need for guiding agents.

It has already been stated above that the angle ai and/or the angle a2 is greater than i0°, particularly preferably greater than 20°. It has proven effective for the angle ai and/or the angle a2 to be greater than 25°, preferably greater than 30°, preferably greater than 35°, for example greater than 40°. It is recommended that the angle ai and/or the angle a2 have a value in the range between i0° and 75°, preferably between 20° and 70°, particularly preferably between 25° and 65° and most preferably between 30° and 65°, for example between 35° and 60°. It is within the scope of the invention that the angles a i and a2 have the same value, so that the two filament air flows meet symmetrically in the contact zone, in particular on both sides, with the air flow and short fibres or with the central air flow and short fibres. However, it is also possible in principle for the angles a i and a2 to have different values.

In a preferred embodiment of the method according to the invention, the air and short fiber flow flows from the outlet channel or from an outlet channel end perpendicularly or substantially perpendicularly to the sieve belt surface of the deposit sieve belt with respect to its flow direction S i. The flow direction S i of the air and short fiber flow is thus directed in particular perpendicularly or substantially perpendicularly to the sieve belt surface of the air-permeable deposit sieve belt. In the context of the invention, this means in particular that the flow vector of the air and short fiber flow runs perpendicularly or substantially perpendicularly to the planar extent of the sieve belt surface.

Within the scope of the invention, it is also contemplated that secondary air is drawn into the intermediate space between the short-fibre air flow and the filament air flow and/or into the intermediate space between the short-fibre air flow and the second filament air flow. In this case, the secondary air is drawn in in particular at a volume flow rate V, whereby V is advantageously the total volume flow rate of the drawn-in secondary air. Preferably, the following applies: V > (V i V2 V) and/or V > (V i V2 V3 V). It is recommended that V is between i and 30 times, preferably between 5 and 25 times, preferably between i0 and 20 times the sum of the volume flow rates V i, V2, V and/or the sum of the volume flow rates V i, V2, V and. In the context of the invention, secondary air is understood to mean in particular air that is additionally drawn in by the flow motion of the air and filament streams and/or the air and short fiber stream, which is neither the air blown out of the meltblown spinning nozzles nor the air exiting the outlet channel with the short pulp fibers. In particular, the air blown out of the meltblown spinning nozzles and the air exiting the outlet channel with the short pulp fibers are referred to as primary air in the context of the invention. In the context of the invention, the term air also includes gas mixtures or fluids similar to air.

The flow of air and short fibers is advantageously accelerated in the outlet channel, in particular by a fan of the defibering equipment. In a preferred embodiment, the defibering equipment therefore has a fan which supplies air to the defibering equipment. It is within the scope of the invention that the air flow for generating the flow of air and short fibers in the defibering equipment is generated by the defibration operation and/or by the blower. In a preferred embodiment of the invention, the defibering equipment is a sawmill. Thus, the air flow for generating the flow of air and short fibers is preferably generated by the grinding operation in the sawmill and/or by the fan of the sawmill. The air flow and short fibers accelerated in the outlet channel, in accordance with the preferred embodiment, leaves the outlet channel with the initial volume flow rate V1.

In a particularly preferred embodiment of the invention, the at least one meltblown spinning nozzle has a plurality of nozzle openings arranged in a row and preferably two air inlet gaps running parallel to the row of nozzle openings on both sides and inclined in the direction of the nozzle openings through which the blown air exits. At least two, in particular both, meltblown spinning nozzles are advantageously designed in this way. The fact that the meltblown spinning nozzle or the meltblown spinning nozzles have a plurality of nozzle openings arranged in a row means, in the context of the invention in particular, that the meltblown spinning nozzle has only a single row of nozzle openings. Such meltblown spinning nozzles are also referred to as single-row nozzles. The meltblown spinning nozzle or the meltblown spinning nozzles each advantageously have at least two, in particular two, air inlet gaps running parallel to the nozzle opening row on both sides. In the context of the invention, the parallel course of the air inlet gap on both sides means in particular that the longitudinal extent of the air inlet gaps runs parallel to the longitudinal extent of the nozzle opening row. Furthermore, it is recommended that the air inlet gaps be inclined towards the nozzle openings or the nozzle opening row. In this way, it is ensured in particular that the blown air exiting the air inlet gaps or the flat air flow exiting the air inlet gaps acts at an angle of attack on the curtain of endless filaments extruded from one side or from opposite sides. The angle of attack of the blown air relative to the flow direction of the produced endless filaments is preferably less than 30°, preferably less than 20°. It is preferred that the endless filaments in the two air inlet gaps of the meltblown spinning nozzle or the meltblown spinning nozzles are subjected to uniform or symmetrical blown air. In principle, however, it is also possible for the endless filaments to be subjected to uneven or asymmetrical stress with respect to the temperature and/or the volume flow rate of the air blown through the two air inlet gaps of the meltblown spinning nozzle.

In another preferred embodiment of the invention, the at least one meltblown spinning nozzle has a plurality of nozzle openings arranged in several rows, with each nozzle opening preferably being associated with an air inlet opening or a separate air inlet opening from which blown air is discharged. Such a meltblown spinning nozzle, which has nozzle openings arranged in several rows for the discharge of the molten plastic filaments, is also referred to as a multi-row nozzle. It is within the scope of the invention that the at least two, in particular both, meltblown spinning nozzles are designed in this way. The fact that each nozzle opening of the meltblown spinning nozzle has an air inlet opening or a separate air inlet opening means in particular within the scope of the invention that the corresponding air inlet opening is assigned or can be directly assigned to the nozzle opening. It is within the scope of the invention that the air inlet openings of the meltblown spinning nozzle surround the respective nozzle opening and, in particular, are arranged coaxially with it. Thus, advantageously, blown air flows coaxially parallel to the plastic melt or the molten plastic filaments from the air inlet opening associated with the nozzle opening and advantageously surrounds the filament produced in the form of a jacket.

In another preferred embodiment of the invention, the at least one meltblown spinning nozzle has a plurality of outlet openings arranged in several rows in the form of nozzle openings and air inlet openings, the outlet openings or the nozzle openings and the air inlet openings preferably being arranged at a distance from one another in a regular and/or irregular pattern and preferably at least 90% of the air inlet openings, in particular each air inlet opening, being assigned at least two nozzle openings and/or preferably at least 90% of the nozzle openings, in particular each nozzle opening, at least two air inlet openings. It is within the scope of the invention that the at least two, in particular both, meltblown spinning nozzles are designed in this way. This embodiment of the invention is characterized in that no separate air inlet opening is directly associated with the respective nozzle openings from which the molten plastic or molten plastic filaments emerge. Rather, at least two air inlet openings are preferably associated with each nozzle opening. In this embodiment, the blown air emerges from the air inlet openings. It is preferred that the nozzle openings are designed such that only the polymer melt emerges from them and that the polymer melt emerges from the nozzle opening, in particular without a blown air flow that is directly associated with the respective nozzle opening or that exits coaxially to the nozzle opening. Advantageously, only the blown air emerges from the air inlet openings. In this preferred embodiment, a portion of the outlet openings of the meltblown spinning nozzle are configured as nozzle openings and one or the other portion of the outlet openings are configured as air inlet openings. In this embodiment, it is recommended that the distances between directly adjacent outlet openings of the meltblown spinning nozzle in at least one nozzle direction be equal or substantially equal over the entire nozzle. It is further preferred that the proportion of nozzle openings in the total number of outlet openings is between 10% and 50%, preferably between 12% and 45%, preferably between 15% and 40%.

If, according to a preferred embodiment of the invention, at least two, in particular two, meltblown spinning nozzles are provided, it is preferred that both meltblown spinning nozzles or all meltblown spinning nozzles are identically designed with regard to the nozzle openings and the air inlet openings or the air inlet gaps. However, in principle, at least two different meltblown spinning nozzles can also be combined within the scope of the method according to the invention. It is also preferred that the outlet openings, in particular the nozzle openings and/or the air inlet openings, of the meltblown spinning nozzles are round or circular.

The invention has recognized that, due to the special flow conditions according to the invention and, in particular, due to the ratio of the sum of the initial volumetric flow rates of the air and short fiber flow and the air and filament flow or the air and filament flows to the volumetric flow rate drawn through the depositing screen belt, a process can be provided with which a nonwoven fabric can be manufactured from endless filaments and short pulp fibers, which is characterized by a very high uniformity of distribution of endless filaments and short pulp fibers and, in particular, by an optimum balance between stability or strength and liquid absorption capacity of the nonwoven material. Particularly advantageous results can be achieved in this respect if the air and filament flow or the air and filament flows (in each case) flow(s) at an angle to the flow direction of the air and short fibre flow and in particular if two air and filament flows flow at an angle on either side to form a central air and short fibre flow, particularly preferably symmetrically. The mixture of endless filaments and short fibres deposited on the depositing screen belt is conveniently a matrix of endless filaments in which the short pulp fibres are embedded.

In a preferred embodiment of the method according to the invention, the endless filaments of the at least one air and filament stream, preferably of the air and filament streams, are sprayed with water between the meltblown spinning nozzle and the deposition screen belt, in particular on the side of the air and filament stream facing away from the air and short fiber stream. For spraying the endless filaments with water, preferably one or in each case one water nozzle is provided, which is arranged in particular on the side of the respective air and filament stream facing away from the air and short fiber stream. The at least one water nozzle or the water nozzles are expediently located on the outside of the air and filament stream or the air and filament streams. It is within the scope of the invention that the water nozzle is associated with the respective meltblown spinning nozzle and preferably arranged below, in particular directly below, the meltblown spinning nozzle in the direction of filament flow. The endless filaments are thus sprayed with water after, in particular immediately after, leaving the meltblown spinning nozzle. In this way, a targeted cooling of the generated endless filaments can be achieved.

It is preferred that the air and short fibre flow leaves the outlet channel with a proportion of 0.0138 to 0.0833 kg, preferably 0.0222 to 0.0694 kg, preferably 0.0277 to 0.05 kg of short pulp fibres per kg of air. It is recommended that the air and short fibre flow leaves the outlet channel with a proportion of short pulp fibres of more than 0.0138 kg, preferably more than 0.0222 kg, preferably more than 0.0277 kg per kg of air. The proportion of short pulp fibres per kg of air can be conveniently controlled and/or regulated by the speed of the defibrating equipment, in particular by the inlet speed of the defibrating equipment.

Furthermore, it is preferred that the at least one air stream and filaments, or the air streams and filaments, exit the meltblown spinning nozzle in a ratio of 0.002 kg to 0.5 kg, preferably 0.01 kg to 0.25, preferably 0.015 kg to 0.12 kg, particularly preferably 0.018 kg to 0.1 kg of endless filaments per kg of air. It is recommended that the at least one air stream and filaments, preferably the air streams and filaments (in each case), exit the meltblown spinning nozzle in a ratio of more than 0.002 kg, preferably more than 0.01 kg, preferably more than 0.015 kg, particularly preferably more than 0.018 kg of endless filaments per kg of air. It is also within the scope of the invention that the air and filament streams, in particular both air and filament streams, exit the meltblown spinning nozzles with the same proportion of endless filaments per kg of air. In an alternative embodiment of the method according to the invention, the air and filament streams, in particular both air and filament streams, exit the meltblown spinning nozzles with a different proportion of endless filaments per kg of air. In a recommended embodiment of the invention, the proportion of endless filaments with which the air and filament streams exit the meltblown spinning nozzles per kg of air can be determined by controlling and/or regulating the mass flow of the thermoplastic plastic and/or the blown air exiting the air inlet gaps or air inlet openings of the meltblown spinning nozzles. According to a particularly preferred embodiment of the invention, the proportion of endless filaments in the deposited nonwoven material is between 10 and 35% by weight, preferably between 15 and 30% by weight, preferably between 20 and 28% by weight.

It has already been explained above that, according to an advantageous embodiment of the invention, the flow of air and short fibres is accelerated in the outlet channel by a fan of the defibration equipment. In this context, it is preferred to condition the air drawn in by the fan of the defibration equipment. Particularly preferably, the conditioned air drawn in by the fan has a relative humidity of more than 65 % at 28 °C.

It is within the scope of the invention that the outlet channel is height-adjustable relative to the sieve belt surface of the deposit sieve belt. The distance a between the outlet channel end and the sieve belt surface is advantageously between 200 and 1000 mm, preferably between 300 and 750 mm, preferably between 400 and 600 mm and particularly preferably between 460 and 530 mm. In these regions, the outlet channel or the outlet channel end can therefore be height-adjustable relative to the sieve belt surface of the deposit sieve belt. Very particularly preferably, the amount of secondary air drawn in can be controlled and/or regulated by adjusting the height of the outlet channel relative to the sieve belt surface of the deposit sieve belt. In the context of the method according to the invention, it is recommended to adjust the height of the outlet channel such that the following is true: V4 > (V1 V2 Vsec) and/or V4 > (V1 V2 V3 Vsec). In this case, the quantity of secondary air drawn in is understood to mean in particular the secondary air or the quantity of secondary air drawn in between the air flow and short fibres and at least one, preferably two, air flow and filaments. In the context of the invention, the term outlet channel end is understood to mean in particular the outlet channel end facing the deposit screen belt. The walls of the outlet channel in the region of the outlet channel end are preferably designed such that the outlet channel end is formed in the internal cross section either constantly or diverging or converging. In this way, the subsequent mixing of the endless filaments and the short pulp fibres in the contact zone can be influenced in particular. The distance a between the outlet channel end and the sieve belt surface is measured in particular perpendicular to the sieve belt surface within the scope of the invention. The ability to control and/or regulate the amount of secondary air drawn in makes it possible to influence the flow conditions, in particular with regard to the supply of secondary air, in a functionally reliable manner. By means of the height adjustment or height adjustment capability of the outlet channel or the outlet channel end, the position of the contact zone can also be adjusted or regulated within the scope of the invention, in particular in combination with the angles a l and/or a2. This makes it possible to advantageously influence the mixing of the endless filaments and the short pulp fibres, in particular in combination with the design of the outlet channel walls in the area of the outlet channel end and preferably by means of a design of the outlet channel walls in the area of the outlet channel end that is constant in internal cross section.

According to the invention, the air and filament stream, preferably both air and filament streams and the air and short fiber stream are brought together in a contact zone above the depositing screen belt. It is recommended that the air and filament streams and the air and short fiber streams are mixed in this contact zone. According to a preferred embodiment of the invention, the mixture of endless filaments and short fibers flows from the contact zone to the depositing screen belt as a homogeneous or substantially homogeneous mixture. By grouping the air and short fiber flow and the air and filament flows under the flow conditions according to the invention and the preferably provided angles, an optimal mixing and distribution of the short pulp fibers and the endless filaments can take place within the scope of the invention, so that, following the contact zone, a homogeneous or substantially homogeneous mixture of endless filaments and short fibers flows onto the depositing screen belt and is deposited as nonwoven material or nonwoven belt. It is advantageous if the mixture of endless filaments and short fibers flows from the contact zone onto the depositing screen belt or into the depositing zone with respect to its flow direction perpendicularly or substantially perpendicularly to the screen belt surface.

It is within the scope of the invention that the air and short fiber flow should convey or transport at least 50 (kg/h)/m, in particular at least 75 (kg/h)/m, preferably at least 100 (kg/h)/m, particularly preferably at least 200 (kg/h)/m of short pulp fibers, relative to the width of the depositing screen belt. The width of the depositing screen belt is understood within the scope of the invention to mean in particular the largest width of the depositing screen belt transversely, in particular perpendicularly, to the longitudinal extent or to the conveying direction of the depositing screen belt. Within the scope of the invention it is possible to arrange at least two, in particular at least three, preferably at least four defibering units, preferably with corresponding blowers and/or outlet channels, along the width of the depositing screen belt. In this way, a particularly uniform supply of the short pulp fibres or the air flow and short fibres can be achieved over the entire width of the depositing screen belt, even with depositing screen belts with a width of at least 1 m, in particular at least 2 m, preferably at least 3 m, preferably at least 4 m.

A particularly preferred embodiment of the process according to the invention is characterized in that the nonwoven material or the nonwoven tape is solidified by means of at least one calender, preferably an embossing pattern being introduced into the nonwoven material or the nonwoven tape via the at least one calender. It is recommended that the solidification is carried out "in-line" using the at least one calender. In the context of the invention this means in particular that the solidification is carried out by the at least one calender after the deposition of the mixture of endless filaments and short fibers as nonwoven material or nonwoven tape. According to a preferred and alternative embodiment of the process according to the invention, the solidification of the nonwoven material or the nonwoven tape is carried out "off-line" by means of at least one calender. In the context of the invention, this means in particular that the nonwoven material or the nonwoven web is removed from the depositing screen belt after it has been deposited on the depositing screen belt and is wound up and unwound again later, and fed to the at least one calender.

It is recommended that the at least one calender has at least one pair of calender rolls through which the nonwoven material or nonwoven web preferably passes under a nip. One of the calender rolls of the calender is advantageously a smooth roll with a smooth outer surface and/or one of the calender rolls of the calender has an embossed pattern on its outer surface. In a preferred embodiment of the invention, the calender or the pair of calender rolls are heated. In the context of the invention, the temperature of the calender rolls is preferably below the melting point of the thermoplastic material of the endless filaments. The calender roll temperature in the context of the method according to the invention is preferably between 50 °C and 150 °C. Furthermore, within the scope of the invention, the line pressure of the calendering roller(s) is in the range between 10 and 120 daN/cm.

It is particularly preferred that the embossing pattern is seamless and that the basic pattern geometry of the embossing pattern has a pressure area in the range of 20 to 50 mm2, preferably 25 to 45 mm2, preferably 30 to 40 mm2, and particularly preferably 32.5 to 37.5 mm2. In the context of the invention, the basic pattern geometry is understood to mean in particular the geometry underlying a repeat element of the embossing pattern. In this context, it is understood that the basic pattern geometry or the repeat element is preferably in each case of the same or substantially the same size, so that the resulting embossing pattern is a regular embossing pattern. In the context of the invention, the seamless embossing pattern is a honeycomb structure, the basic pattern geometry or its repeat element of which is expediently a hexagon or a regular hexagon. The embossing pattern thus preferably consists of a plurality of regular hexagons of the same size, adjacent to each other, the inner surface of the hexagon preferably forming the non-pressed part of the embossing pattern.

In another preferred embodiment of the invention, the embossing pattern is interrupted and consists in particular of a plurality of elements not connected to one another, preferably of dots and/or lines, the elements preferably each having a pressure area of less than 2 mm2, preferably less than 1.5 mm2, preferably less than 1.1 mm2, particularly preferably less than 0.55 mm2. Within the scope of the invention, it is also possible to combine an embossing pattern without interruptions with an embossing pattern having interruptions.

It is advantageous if the height of the basic pattern geometry or the elements of the embossed pattern is in the range between 0.3 and 2.0 mm, preferably between 0.4 and 1.8 mm, preferably between 0.5 and 1.6 mm. The height of the basic pattern geometry relates in this respect to the height difference or the average height difference between the pressing surface and the non-pressed areas of the embossed pattern. Within the scope of the invention, the proportion of the pressing surface of the embossed pattern to the total surface area of the nonwoven material or nonwoven tape is between 2.5% and 25%, preferably between 5% and 15%, preferably between 5.25% and 12.5%.

With regard to the design of the embossing pattern described above, it is also understood that the corresponding roller of the pair of calendering rollers having the embossing pattern has a complementary embossing pattern on its outer surface. The calender or the calendering roller has in particular a proportion of pressing surface or a pressing surface of 2.5% to 25%, preferably 5% to 15% and preferably 5.25% to 12.5%.

In order to solve the technical problem, the invention further teaches a device for producing a nonwoven material from fibers, in particular by a method described above, the device having at least one meltblown spinning nozzle, preferably at least two meltblown spinning nozzles for producing endless filaments made of thermoplastic plastic,

there being also at least one defibering equipment for producing short pulp fibers and an outlet channel for guiding the short pulp fibers or a flow of air and short fibers,

the device comprising at least one air-permeable depositing screen belt for depositing the short pulp fibres and the endless filaments as a mixture of endless filaments and short fibres on a nonwoven fabric or a nonwoven belt and having at least one suction device with which air or process air can be sucked in with a volume flow rate V4 from below through the depositing screen belt into the depositing zone of the fibres or the mixture of endless filaments and short fibres,

the device being configured with the directive that the flow of air and short fibers (5) exits the outlet channel (6) and flows with an initial volumetric flow rate V1 and a flow direction S1 in the direction of the air-permeable deposit screen belt (8) and that the endless filaments of the at least one meltblown spinning nozzle (2) flow as a flow of air and filaments (9) with an initial volumetric flow rate V2 in the direction of the flow of air and short fibers (5) and that the volumetric flow rate V4 is greater than the sum of the volumetric flow rates V1 and V2.

In a preferred embodiment, the device has at least two, in particular two, meltblown spinning nozzles. It is preferred that a first meltblown spinning nozzle is arranged in front of the outlet channel in the conveying direction of the depositing screen belt and a second meltblown spinning nozzle is arranged downstream of the outlet channel in the conveying direction of the depositing screen belt. Within the scope of the invention, the at least one meltblown spinning nozzle, preferably the at least two or both meltblown spinning nozzles are arranged at an angle of inclination to the outlet channel. The angle of inclination between the meltblown spinning nozzles and the outlet channel is expediently (in each case) at least 10°, preferably at least 20° and preferably at least 25°. It is further preferred that the angle of inclination between the meltblown spinning nozzles and the outlet channel (in each case) is at least 30°, particularly preferably at least 35°, for example at least 40°. It is recommended that at least the angle of inclination between one meltblown spinning nozzle and the outlet channel, preferably between the two meltblown spinning nozzles and the outlet channel (in each case) is between 10° and 75°, preferably between 20° and 70°, particularly preferably between 25° and 65° and very particularly preferably between 30° and 65°, for example between 35° and 60°. In this way, air and filament streams can flow from the meltblown spinning nozzles into the depositing screen belt at an angle a l or a2 to the flow direction S1 of the air and short fiber stream and into the air and short fiber stream. It is recommended that the angle of inclination between the meltblown spinning nozzles and the outlet channel be adjustable or regulated.

It is preferred that the outlet channel is designed so that it can be adjusted in height relative to the sieve belt surface of the deposit sieve belt. It has proven effective that the distance a between the end of the outlet channel and the sieve belt surface can be adjusted in a range of between 200 and 1000 mm, preferably between 300 and 750 mm, preferably between 400 and 600 mm, particularly preferably between 460 and 530 mm.

In a preferred embodiment of the device according to the invention, the defibrating equipment has at least one fan for accelerating the short pulp fibres or the flow of air and short fibres in the outlet channel.

The nonwoven material produced by the method according to the invention and/or by the device according to the invention preferably has a thickness in the range from 0.1 to 3 mm, preferably from 0.2 to 2 mm and preferably from 0.3 to 1.5 mm. For the purposes of the invention, the thickness of the nonwoven material is understood in particular to mean the greatest thickness of the nonwoven material transversely, in particular perpendicularly or substantially perpendicularly to its plane extent and in particular after a preferably provided solidification or calendering step.

The invention is based on the recognition that, by means of the process according to the invention, a nonwoven fabric can be produced from endless filaments and short pulp fibres which fulfils all requirements both in terms of stability or strength and in terms of liquid absorption capacity. The measures according to the invention allow in this respect an optimum balance between the strength of the nonwoven material and the liquid absorption capacity. The flow conditions according to the invention and the preferably provided arrangement of the meltblown spinneret or spinnerets and the outlet channel for the short pulp fibres allow in particular an optimum mixing of the endless filaments and the short pulp fibres, so that a nonwoven material with a very uniform distribution of the endless filaments and the short pulp fibres is obtained. In this way, a nonwoven material which fulfils all requirements can be provided with a relatively small proportion of endless filaments. It should also be emphasised that the measures according to the invention are not very laborious and the method according to the invention is therefore characterised by high cost-effectiveness. This also applies to the device according to the invention.

The invention will be explained in more detail below by means of a drawing which represents only one exemplary embodiment. In a schematic representation, the following are shown:

Figure 1 a vertical section of a device according to the invention for carrying out the method according to the invention,

Figure 2 a bottom view of a meltblown spinning nozzle according to the invention in a first embodiment,

Figure 3 a vertical section of the object according to Figure 2,

Figure 4 a bottom view of a meltblown spinning nozzle according to the invention in a second embodiment,

Figure 5 a bottom view of a meltblown spinning nozzle according to the invention in a third embodiment,

Figure 6A a top view of a fragment of a nonwoven material according to the invention with an embossed pattern,

Figure 6B a cross section along A-A according to Figure 6A.

1 shows a device according to the invention for producing a nonwoven material 1 from fibres. Two meltblown spinning nozzles 2, 3 produce endless filaments of thermoplastic plastic. Within the scope of the invention and in the exemplary embodiment, the thermoplastic plastic can be polypropylene. 1 shows that the short pulp fibres are produced from pulp, preferably and in the exemplary embodiment from solid pulp 19, by means of at least one defibration system 4. The defibration system 4 is conveniently and in the exemplary embodiment a sawmill. According to the invention, at least one air and short fiber flow 5 is generated from the short pulp fibers in the defibering equipment 4. The air and short fiber flow 5 is preferably and in the exemplary embodiment accelerated in the outlet channel 6 by a fan 7 of the defibering equipment 4. The blower 7 conveniently and in the exemplary embodiment supplies air to the defibering equipment 4. The air flow for generating the air and short fiber flow 5 is generated within the scope of the invention and in the exemplary embodiment from the grinding process in the defibering equipment 4 or in the sawmill and by the blower 7.

According to the invention, the accelerated air and short fiber stream 5 leaves the outlet channel 6 with an initial volume flow rate V1. In the context of the invention, initial volume flow rate V1 is understood in particular to mean the volume flow rate of the air and short fiber stream 5 immediately after leaving the outlet channel 6. The short fiber air stream 5 flows towards the deposit screen belt 8 in a flow direction S1 which, preferably and in the exemplary embodiment, is perpendicular or substantially perpendicular to the screen belt surface of an air-permeable deposit screen belt 8. In the exemplary embodiment, the air-permeable deposit screen belt 8 is advantageously designed as an endlessly circulating deposit screen belt 8.

The endless filaments produced by the meltblown spinning nozzles 2, 3 advantageously flow as air and filament streams 9, 10 with an initial volume flow rate V2 or V3 in the exemplary embodiment from the meltblown spinning nozzles 2, 3 into the air and short fiber stream 5. The initial volume flow rate V2 or V3 is understood in particular to mean the volume flow rate of the air and filament streams 9, 10 which is located directly or immediately below the meltblown spinning nozzles 2, 3 after the endless filaments have been subjected to blown air.

In the context of the invention and in the exemplary embodiment, a first air and filament flow 9 flows upstream of the short fiber air flow 5 in the conveying direction F of the depositing screen belt 8. The air and filament flow 9 flows at an angle a1 relative to its flow direction S2 to the flow direction S1 of the short fiber air flow 5. The second air and filament flow 10 flows downstream of the short fiber air flow 5 in the conveying direction F of the depositing screen belt 8. This second air and filament flow 10 flows at an angle a2 relative to its flow direction S3 to the flow direction S1 of the short fiber air flow 5. The air and filament flows 9, 10 thus preferably and in the exemplary embodiment flow into the short fiber air flow 5 from both sides of the central air and short fiber flow 5 at angles a1 and a2. a2. Within the scope of the invention, the angles a1 and a2 are preferably greater than 20°, particularly preferably greater than 25°. In the exemplary embodiment according to the figures, the angles a1 and a2 can each be approximately 30°. Preferably and within the scope of the exemplary embodiment, the angles a1 and a2 have the same value or substantially the same value.

Conveniently and in the exemplary embodiment, the air and filament streams 9, 10 and the air and short fibre stream 5 are collected above the depositing screen belt 8 in a contact zone 11 and are deposited as a mixture of endless filaments and short fibres 12 in a deposit zone 13 on the depositing screen belt 8 to form the nonwoven material 1 or the nonwoven belt. Preferably and in the exemplary embodiment, the air and filament streams 9, 10 flow in the region or shortly before the contact region 11 with respect to their flow direction S2 or S3 at the angle a1 or a2 to the flow direction S1 of the air and short fiber stream 5. Within the scope of the invention and in the exemplary embodiment, the angles a1 and a2 relate in particular to the angles of inclination at which the air and filament streams 9, 10 meet the air and short fiber stream 5 in the contact region 11. Preferably and in the exemplary embodiment, the two filament air streams 9, 10 flow along the entire flow path from the respective meltblown spinning nozzle 2, 3 to the contact region 11 with respect to their flow direction S2 or S3 at the angle a1 or a2 to the flow direction S1. of the air and short fiber flow 5. It is advisable and in the exemplary embodiment that the air and filament flows 9, 10 flow in a straight line or substantially in a straight line. Preferably and in the exemplary embodiment according to FIG. 1, the air and filament flows 9, 10 also flow symmetrically towards the air and short fiber flow 5 and impinge symmetrically on the air and short fiber flow 5 in the contact zone 11. The two air and filament flows 9, 10 and the air and short fiber flow 5 preferably and in the exemplary embodiment flow without guide agents from the meltblown spinning nozzles 2, 3 or from the outlet channel 6 into the contact zone 11.

In the preferred embodiment, secondary air is drawn into the intermediate spaces between the filament air flows 9, 10 and the short fiber air flow 5. In particular, the secondary air is drawn in at a volume flow rate V, where V is advantageously the total volume flow rate of the drawn in secondary air. In addition, according to the invention, air or process air is drawn in from below through the depositing screen belt 8 into or at least into the depositing area 13 of the fibers or the mixture of endless filaments and short fibers 12 at a volume flow rate V. For this purpose, within the scope of the invention and in the preferred embodiment, a suction device 16 or a suction fan is provided below the depositing screen belt 8, in particular below the depositing area 13. The volume flow rate V is preferably greater than the sum of the volume flow rates V, V and V. More preferably, the volumetric flow rate V4 is greater than or equal to the sum of the volumetric flow rates V1, V2, V3 and Vsec.

In a preferred embodiment of the invention, the meltblown spinning nozzles 2, 3 each have a plurality of nozzle openings 17 arranged in a row, from which the molten plastic filaments are preferably extruded in the context of the method according to the invention. Preferably, two air inlet gaps 18 each extend parallel to and on either side of the row of nozzle openings 17. This can be seen in FIGS. 2 and 3. Preferably, the blown air exits the air inlet gaps 18. The plastic filaments extruded from the nozzle openings 17 are advantageously extruded into the blown air flow. Within the scope of the invention and in the exemplary embodiment according to Figures 2 and 3, the meltblown spinning nozzles 2, 3 have only one row of nozzle openings 17 and are therefore designed as single-row nozzles. The fact that the air inlet gaps 18 run parallel to the row of nozzle openings 17 on both sides means, within the scope of the invention, in particular, that the longitudinal extent of the air inlet gap 18 runs parallel to the longitudinal extent of the row of nozzle openings 17 (Figure 2). The air inlet gaps 18 are preferably inclined towards the nozzle openings 17 or towards the nozzle opening row 17 within the scope of the embodiment according to FIGS. 2 and 3. The blown air exiting the air inlet gaps 18 or the flat flow of blown air thus acts laterally at an angle of attack on the extruded endless filaments (FIG. 3).

4 shows a bottom view of a further preferred embodiment of the meltblown spinning nozzles 2, 3. In the preferred embodiment of the meltblown spinning nozzles 2, 3 according to FIG. 4, a plurality of nozzle openings 17 arranged in multiple rows are provided, with each nozzle opening 17 being associated with an air inlet opening 21 or a separate air inlet opening 21 from which blown air is discharged. Such a meltblown spinning nozzle, which has nozzle openings 17 arranged in multiple rows for the discharge of the molten plastic filaments, is also referred to as a multi-row nozzle. Preferably, in the exemplary embodiment according to FIG. 4, each air inlet opening 21 is directly associated with a specific nozzle opening 17. In the exemplary embodiment according to Figure 4, the air inlet openings 21 preferably surround the respective nozzle opening 17 coaxially. The blown air thus flows coaxially parallel to the plastic melt or the molten plastic filaments from the air inlet opening 21 associated with the respective nozzle opening 17.

Another preferred embodiment of the meltblown spinning nozzles 2, 3 is shown in Fig. 5. According to this preferred embodiment, the meltblown spinning nozzle 2 or the meltblown spinning nozzles 2, 3 have a plurality of outlet openings arranged in several rows in the form of nozzle openings 17 (shown as open circles in Fig. 5) and air inlet openings 21 (shown as filled circles in Fig. 5). Conveniently and in the exemplary embodiment, the outlet openings or nozzle openings 17 and the air inlet openings 21 are arranged at a distance from each other in a regular pattern. At least two air inlet openings 21 are associated with each nozzle opening 17. This means in particular that at least two air inlet openings 21 are arranged directly adjacent to each nozzle opening 17. Preferably and in the exemplary embodiment, at least two nozzle openings 17 are also arranged directly adjacent to each air inlet opening 21. In the context of the preferred embodiment according to FIG. 5, only blown air emerges from the air inlet openings 21. It is preferred that the nozzle openings 17 are designed such that only the polymer melt exits them and that the polymer melt exits the nozzle opening 17, in particular without a blown air flow which is directly associated with the respective nozzle opening 17 or which exits coaxially to the nozzle opening 17. Suitably and in the exemplary embodiment according to FIG. 5, a portion of the outlet openings of the meltblown spinning nozzle 2 or of the meltblown spinning nozzles 2, 3 are designed in the form of nozzle openings 17 and one or the other portion of the outlet openings are designed in the form of air inlet openings 21. Within the scope of this embodiment and in the exemplary embodiment, the distances between the directly adjacent outlet openings of the meltblown spinning nozzle in the longitudinal and transverse directions of the spinning nozzle meltblown 2, 3 are equal or essentially equal to each other throughout the nozzle. 2, 3.

In the context of the invention and in the exemplary embodiment, the air and filament streams 9, 10 are sprayed with water between the meltblown spinning nozzle 2, 3 and the deposit screen belt 8 on the side of the air and filament stream 9, 10 opposite the air and short fiber stream 5. For this purpose, a water nozzle 20 is provided in each case, which in the exemplary embodiment is expediently arranged on the side of the respective air and filament stream 9, 10 facing away from the air and short fiber stream 5. The water nozzles 20 are therefore preferably and in the exemplary embodiment located on the outside of the air and filament streams 9, 10 and are particularly preferably arranged in the filament flow direction below or directly below the meltblown spinning nozzles 2, 3.

The amount of secondary air drawn in can be controlled and/or regulated within the scope of the method according to the invention or with the device according to the invention, preferably by adjusting the height of the outlet channel 6 or the outlet channel end 14 in relation to the sieve belt surface of the deposit sieve belt 8. It is recommended that the height of the outlet channel 6 be set such that the following applies: V4 > (V1 V2 Vsec) and/or V4 > (V1 V2 V3 Vsec). The outlet channel 6 is preferably configured to be height-adjustable relative to the sieve belt surface of the deposit sieve belt 8. The distance a between an outlet channel end 14 and the sieve belt surface is expediently between 200 and 1000 mm, preferably between 300 and 750 mm. In the context of the invention, the distance a is measured between the outlet channel end 14 and the sieve belt surface perpendicular to the sieve belt surface. The walls of the outlet channel 6 in the region of the outlet channel end 14 are preferably and in the exemplary embodiment designed such that the outlet channel end 14 is configured divergently in the internal cross section. Due to the height adjustability or height adjustment of the outlet channel 6 and the design of the walls of the outlet channel 6 or the outlet channel end 14, the position of the contact zone 11 can be adjusted or regulated within the context of the invention, in particular in combination with the choice of the angles a 1 and a2. This also makes it possible to advantageously influence the mixing of the endless filaments and the short pulp fibers.

It is preferred that the mixture of endless filaments and short fibers 12 flows from the contact zone 11 to the depositing screen belt 8 as a homogeneous or substantially homogeneous mixture. The homogeneous mixture of short fibers and endless filaments 12 is then advantageously deposited in the deposit zone 13 on the depositing screen belt 8 to form the nonwoven material 1 or the nonwoven belt. It is advisable and in the exemplary embodiment according to FIG. 1 , the mixture of endless filaments and short fibers 12 flows from the contact zone 11 to the depositing screen belt 8 or to the deposit zone 13 with respect to its flow direction perpendicularly or substantially perpendicularly to the screen belt surface.

The nonwoven 1 is solidified "in-line" by means of at least one calender 15 according to a preferred embodiment of the method according to the invention and in the exemplary embodiment. In the exemplary embodiment, the at least one calender 15 has at least one pair of calendering rollers through which the nonwoven 1 is preferably guided under pressure. It is also preferred that an embossing pattern is introduced into the nonwoven 1 or the nonwoven web by means of the at least one calender 15. For this purpose, at least one of the calendering rollers of the calender 15 can have an embossing pattern on its outer surface.

Figure 6A shows a top view of a fragment of a nonwoven material according to the invention with an embossing pattern. Figure 6B shows a cross section of the object according to Figure 6A along AA. Preferably and in the exemplary embodiment according to Figure 6A, the embossing pattern is configured uninterruptedly. The basic pattern geometry or the repeating element of the embossing pattern is preferably a regular hexagon, so that the embossing pattern preferably and in the exemplary embodiment consists of a plurality of adjacent and equally sized regular hexagons and is therefore configured in particular as a honeycomb-shaped embossing pattern. In Figure 6B it can be seen that the hexagonal inner surface expediently forms the non-pressed part of the embossing pattern.

It is recommended that the height h of the basic pattern geometry or the elements of the embossing pattern be between 0.3 and 2.0 mm. In the exemplary embodiment according to FIGS. 6A and 6B, the height of the basic pattern geometry or the regular hexagons may be approximately 1.5 mm. The height h of the basic pattern geometry is the height difference or the average height difference between the pressing surface and the non-pressed areas of the embossing pattern. In the context of the invention, the proportion of the pressing surface of the embossing pattern to the total surface of the nonwoven material is also between 2.5% and 25%, preferably between 5% and 15%. It is also understood that the corresponding roller of the pair of calendering rollers having the embossing pattern has a complementary embossing pattern on the outer surface.

Claims (19)

1. A method for producing a nonwoven material (1) from fibres, wherein endless filaments of thermoplastic plastic are produced by means of at least one meltblown spinning nozzle (2), preferably by means of at least two meltblown spinning nozzles (2, 3), and wherein short pulp fibres are also produced by means of at least one defibre separator (4), wherein at least one flow of air and short fibres (5) is produced from the short pulp fibres in the defibre separator (4), which flows out of the defibre separator (4) at an initial volume flow rate V1 and a flow direction S1 towards an air-permeable depositing screen belt (8), the endless filaments flowing from the at least one meltblown spinning nozzle (2) as a flow of air and filaments (9) with an initial volumetric flow rate V2 in the direction of the flow of air and short fibers (5), the air and filament flow (9) and the air and short fibre flow (5) being grouped above the depositing screen belt (8) in a contact zone (11) and being deposited as a mixture of endless filaments and short fibres (12) in a deposit zone (13) on the depositing screen belt as nonwoven (1) or nonwoven belt, air or process air being drawn into the deposit zone (13) of the fibres or the mixture of short fibres and endless filaments (12) via the depositing screen belt (8) with a volume flow rate V4, the volume flow rate V4 being greater than the sum of the volume flow rates V1 and V2. 2. Method according to claim 1, wherein at least two meltblown spinning nozzles (2, 3) are present, the endless filaments being discharged from the second meltblown spinning nozzle (3) as a second flow of air and filaments (10) with an initial volume flow V3 in the direction of the flow of air and short fibres (5), the volume flow V4 being preferably greater than the sum of the volume flows V1, V2 and V3, the flow of air and filaments (9) particularly preferably flowing in the conveying direction (F) of the depositing screen belt (8) before the flow of air and short fibres (5) and the second flow of air and filaments (10) flowing in the conveying direction (F) of the depositing screen belt (8) behind the flow of air and short fibres (5). 3. Method according to one of claims 1 or 2, wherein the air and filament flow (9) flows at least in zones or sections at an angle a1 to the flow direction S1 of the air and short fibre flow (5) relative to its flow direction S3 and preferably the second air and filament flow (10) flows at least in zones or sections at an angle a2 to the flow direction S1 of the air and short fibre flow (5), wherein the angle a1 and/or the angle a2 is preferably greater than 10°, particularly preferably greater than 20°, very particularly preferably greater than 25°. 4. Method according to one of claims 1 to 3, the flow of air and short fibres (5) flowing from the outlet channel (6) or an outlet channel end (14) perpendicularly or substantially perpendicularly to the sieve belt surface of the deposit sieve belt (8) with respect to its flow direction S1. 5. Method according to one of claims 1 to 4, wherein secondary air is drawn into the intermediate space between the air flow and short fibers (5) and the air flow and filaments (9) and/or into the intermediate space between the air flow and short fibers (5) and the second air flow and filaments (10). 6. Method according to one of claims 1 to 5, the flow of air and short fibres (5) being accelerated in the outlet channel (6), in particular by means of a fan (7) of the defibration equipment (4). 7. Method according to one of claims 1 to 6, the at least one meltblown spinning nozzle (2, 3) having a plurality of nozzle openings (17) arranged in a row and preferably two air inlet gaps (18) running on both sides parallel to the row of nozzle openings (17) inclined in the direction of the nozzle openings (17) and from which blown air emerges. 8. Method according to one of claims 1 to 6, the at least one meltblown spinning nozzle (2, 3) having a plurality of nozzle openings (17) arranged in several rows, each nozzle opening (17) preferably being associated with an air inlet opening (21) or a separate air inlet opening (21) through which the blown air exits. 9. Method according to one of claims 1 to 6, the at least one meltblown spinning nozzle (2, 3) having a plurality of outlet openings arranged in several rows in the form of nozzle openings (17) and air inlet openings (21), the outlet openings or the nozzle openings (17) and the air inlet openings (21) preferably being arranged at a distance from one another in a regular and/or irregular pattern and preferably at least two nozzle openings (17) and/or at least two air inlet openings (21) being associated with each air inlet opening (21). 10. Method according to one of claims 1 to 9, wherein the endless filaments of the at least one air and filament flow (9), preferably the air and filament flows (9, 10), are sprayed with water between the meltblown spinning nozzle (2, 3) and the depositing screen belt (8), in particular on the side facing away from the air and filament flow (9, 10) oriented in the opposite direction to the air and short fibre flow (5). 11. Method according to one of claims 1 to 10, the flow of air and short fibres (5) exiting the outlet channel (6) in a proportion of 0.0138 to 0.0833 kg, preferably 0.0222 to 0.0694 kg, preferably 0.0277 to 0.05 kg of short pulp fibres per kg of air. 12. Method according to one of claims 1 to 11, wherein the at least one air and filament stream (9) or the air and filament streams (9, 10) exit the meltblown spinning nozzles (2, 3) in a ratio of 0.002 kg to 0.5 kg, preferably 0.01 kg to 0.25, preferably 0.015 kg to 0.12 kg, particularly preferably 0.018 kg to 0.1 kg of endless filaments per kg of air. 13. Method according to one of claims 1 to 12, wherein the outlet channel (6) is height-adjustable relative to the sieve belt surface of the deposit sieve belt (8) and the distance (a) between the end of the outlet channel (14) and the sieve belt surface is in particular between 200 and 1000 mm, preferably between 300 and 750 mm, preferably between 400 and 600 mm, particularly preferably between 460 and 530 mm, wherein the amount of secondary air drawn in can be conveniently controlled and/or regulated by adjusting the height of the outlet channel (6) relative to the sieve belt surface of the deposit sieve belt (8). 14. Method according to one of claims 1 to 13, wherein the flow of air and short fibres (5) relative to the width (b) of the depositing sieve belt (8) is at least 50 (kg/h)/m, in particular at least 75 (kg/h)/m, preferably at least 100 (kg/h)/m and particularly preferably at least 200 (kg/h)/m of the short pulp fibres. 15. Method according to one of claims 1 to 14, wherein the nonwoven (1) or the nonwoven tape is solidified by means of at least one calender (15), preferably an embossing pattern being applied to the nonwoven material (1) or the nonwoven tape by means of the at least one calender (15). 16. Method according to claim 15, wherein the embossing pattern is designed without interruptions and the basic pattern geometry of the embossing pattern has a pressure area in the range of 20 to 50 mm2, preferably 25 to 45 mm2, preferably 30 to 40 mm2, particularly preferably 32.5 to 37.5 mm2. 17. Method according to one of claims 15 or 16, the embossing pattern having interruptions and in particular consisting of a plurality of elements not connected to one another, preferably points and/or lines, the elements expediently each having a pressure area of less than 2 mm2, preferably less than 1.5 mm2, preferably less than 1.1 mm2, particularly preferably less than 0.55 mm2. 18. Device for producing a nonwoven fabric from fibres by a process according to one of claims 1 to 17, the device comprising at least one meltblown spinning nozzle (2), preferably at least two meltblown spinning nozzles (2, 3), for producing endless filaments of thermoplastic plastic, there being also at least one defibration equipment (4) to produce short pulp fibers and an outlet channel (6) to guide the short pulp fibers or a flow of air and short fibers (5), the device presenting at least one air-permeable depositing screen belt (8) for depositing the short pulp fibers and the endless filaments as a mixture of endless filaments and short fibers (12) on a nonwoven fabric (1) or a nonwoven belt and there being at least one suction device (16) with which air or process air can be sucked with a volume flow rate V4 from below through the depositing sieve belt (8) into the depositing area (13) of the fibers or the mixture of endless filaments and short fibers (12), the device being configured with the directive that the flow of air and short fibers (5) exits the outlet channel (6) and flows with an initial volumetric flow rate V1 and a flow direction S1 in the direction of the air-permeable deposit screen belt (8) and that the endless filaments of the at least one meltblown spinning nozzle (2) flow as a flow of air and filaments (9) with an initial volumetric flow rate V2 in the direction of the flow of air and short fibers (5) and that the volumetric flow rate V4 is greater than the sum of the volumetric flow rates V1 and V2. 19. Device according to claim 18, the device comprising at least two meltblown spinning nozzles (2, 3), a first meltblown spinning nozzle (2) being arranged in front of the outlet channel (6) in the transport direction of the deposit screen belt (8) and a second meltblown spinning nozzle (3) being arranged behind the outlet channel (6) in the transport direction of the deposit screen belt (8).