EP4058263A1

EP4058263A1 - Nozzle device and manufacturing method for a nozzle device

Info

Publication number: EP4058263A1
Application number: EP20801199.9A
Authority: EP
Inventors: Martin Hoss; Lothar Rufeis
Original assignee: Deutsche Institute fuer Textil und Faserforschung Stuttgart; Deutsche Institute fuer Textil und Faserforschung Denkendorf DITF
Current assignee: Deutsche Institute fuer Textil und Faserforschung Stuttgart; Deutsche Institute fuer Textil und Faserforschung Denkendorf DITF
Priority date: 2019-11-13
Filing date: 2020-11-02
Publication date: 2022-09-21
Also published as: DE102019130565A1; WO2021094122A1; JP2023502212A; US20220389617A1; CA3161331A1

Abstract

A nozzle device (14) according to the invention for producing a random-laid fiber product (34) comprises a melt nozzle (15) having an arrangement (38, 39, 40) of a plurality of melt channels (22). The nozzle device (14) comprises a gas channel (17, 18) having an opening (31, 32) which is associated with a plurality of melt channels (22) of the arrangement (38, 39, 40), wherein the gas channel (17, 18) is designed to produce a gas emission which the melt emitted from the melt channels (22) collects. According to the invention, the melt nozzle (15) comprises an arrangement of capillary tubes (36) in order to form the melt channels (22). A method (100) according to the invention for producing a nozzle device (14) comprises the providing (101) of a nozzle body (15) having one or more receiving channels (35) and the arranging (102) and fastening (103) of capillary tubes (36) in the one or more receiving channels (35).

Description

NOZZLE DEVICE AND METHOD OF MANUFACTURING A NOZZLE DEVICE

The invention relates to a nozzle device for producing a random fiber product.

[0002] From WO 92/07121 a meltblow nozzle device is known which has a melt nozzle with a dispensing tip which has two surfaces which enclose an angle and which meet in a strip-shaped surface section. The strip-shaped surface section has a plurality of openings which form the mouths of melt channels which extend through the dispensing tip. A polymer in a flowable state can be applied to the melt channels in order to expel the polymer from the openings. Plates are attached to the melt nozzle which, with the discharge tip of the melt nozzle, form slot-shaped air discharge channels which are associated with the melt channels to discharge air to either side of the series of openings essentially in the form of converging air blades or blades. This type of meltblow nozzle (also called the Exxon principle) is relatively easy to manufacture. However, melt channels can only be drilled with a length-to-diameter ratio (L / D) of a maximum of 20, usually <15, so that the formation of the finest fibers is limited.

From US 6833 104 B2 a nozzle device is known by means of which very fine polymer fibers can be produced. The nozzle is made by connecting thin plates into which the melt channels are introduced by etching. This manufacturing technique allows a very long time Melt channels and the nozzle can withstand high pressures. However, the manufacturing process is very expensive. In addition, due to the design, such nozzles cannot be used in existing standard spinning heads.

US 2005/0056956 A1 discloses a nozzle device with a nozzle plate which delimits a cavity for being hit with gas. Melt nozzles, which can be fed with polymer melt, extend through the cavity. The melt nozzles extend through a gas distribution plate, an opening in a spacer and through receiving openings in an end plate. The receiving openings form gas ejection openings, one gas ejection opening being assigned to each melt nozzle. The melt nozzle is arranged in the gas ejection opening such that gas can be ejected around the melt nozzle between the melt nozzle and the edge of the gas ejection opening, so that the gas surrounds the end of the melt nozzle and the polymer melt ejected from the melt nozzle. The size of the individual melt nozzles with their associated gas outlet openings requires the melt nozzles to be arranged over a relatively large area in order to achieve a sufficient number of nozzles. This in turn makes the homogeneous melt distribution and gas distribution more difficult in comparison to meltblow nozzle devices with melt nozzles arranged on a line.

In addition to the melt throughput rate, the number of melt channels is the decisive factor with regard to productivity and thus very important for the economic viability of a meltblow system. Nozzles used in industry include capillary bores ranging in number from 30 to 50 holes per inch (HPI). The nozzles must be made of a high-alloy tool steel, which can withstand strong temperature changes over a long period of time Withstands period. The melt throughput rate depends on the pressure with which the melt is applied in order to force it out of the nozzle. Depending on the material and construction, there are limits here.

The object of the present invention is to provide an improved concept for a meltblow nozzle device.

This object is achieved with a nozzle device according to claim 1 and a method for producing a nozzle device according to claim 11:

The nozzle device according to the invention for producing a random fiber product or meltblow nozzle device has a melt nozzle with an arrangement of several melt channels and a gas channel with an orifice which is assigned to several melt channels of the arrangement. The nozzle device can have several gas channels, the mouths of which are each assigned to several melt channels of the arrangement. The gas channel is set up to generate a gas ejection which detects the melt ejected from the mouths of the melt channels. The melt nozzle according to the invention has an arrangement of capillary tubes to form the melt channels. In particular, the mouths of the melt channels can each be formed by a capillary tube. The gas channel or channels are preferably gap-shaped. The mouth or mouths of the gas channel (s) preferably extend along the arrangement of capillary tubes, which can in particular be a row or several (at least two) rows of capillary tubes. A mouth can be assigned to at least a number of melt channels.

If, as according to the invention, the melt channels are formed by capillary tubes, melt channels can be formed det, which have a large length-to-diameter ratio. In this way, with a given diameter of the melt channels, the nozzle device can be designed with a relatively large wall thickness adjacent to the melt channels. In particular, the receiving channel in the melt nozzle for receiving one or more capillary tubes can have a great length, which allows the melt nozzle to be very stable. This in turn allows the melt channels to be subjected to a relatively high melt pressure, which in turn leads to a high melt throughput rate. Overall, the economy and productivity can be increased compared to known nozzle devices in which an arrangement of several melt channels is assigned to a gas channel. The invention also enables extremely fine fibers to be produced. So far, the fineness has been limited by the fact that the bores that form the melt discharge channels could not have a correspondingly fine diameter due to the manufacturing process. Because of the maximum length-to-diameter ratios that can be generated by means of bores, an even finer bore diameter would have led to a correspondingly even shorter length of the melt channels and, as a result, to a smaller wall thickness around the melt ejection openings. This in turn might have made it necessary to reduce the pressure with which the melt channels are acted upon. With the invention, long-existing technical limits can be overcome. With the long melt ejection channels possible according to the invention, very fine fibers can be produced with high reproducibility and high productivity.

[0010] Further advantageous optional features and embodiments emerge from the following description.

The nozzle device is preferably for a Pressurization for dispensing the melt of 60 bar or more, preferably even 100 bar or more, is designed. In particular, the wall thickness of the melt nozzle at the melt channels is preferably so great that they can be subjected to a corresponding pressure.

The capillary tubes can be arranged in one or more receiving channels. The one or more receiving channels are preferably closed around the capillary tube or tubes which the receiving channel contains. The one or more receiving channels can be closed, for example, around the capillary tube or tubes which the receiving channel contains, in that the receiving channel around the capillary tube or tubes is filled with solder.

It is possible, for example, that a separate receiving channel is provided for each capillary tube.

In the sense of a particularly high stability of the melt nozzle, the receiving channel or channels can each have a length which is at least half as large as the length of each of the capillary tubes of the nozzle device manufactured.

In terms of a high density of melt channels, it is considered advantageous if several capillary tubes are arranged in a receiving channel. The recording channel can be gap-shaped. The capillary tubes are arranged in the receiving channel at a small distance from one another, but preferably capillary tube wall to capillary tube wall.

The capillary tubes can be arranged in the receiving channel in one or more (at least two) rows. With several rows, a high line density of melt channels can be achieved, with the combined number of, for example, being used to determine the line density Melt channels along and on an imaginary straight line can never be determined, the line being perpendicular to the direction of flow through a melt channel. The capillary tubes of a row can be arranged offset to the capillary tubes of an adjacent row and a portion of each capillary tube of a row can be arranged between successive Ka pillarrohre in the adjacent row, so that the capillary tubes are arranged closely together in the sense of a high density of mouths .

The inner diameter of the capillary tubes can, for example, be less than or equal to 500 micrometers, less than or equal to 400 micrometers, less than or equal to 300 micrometers or less than or equal to 200 micrometers, in particular less than or equal to 100 micrometers, for example 50 micrometers .

The use of capillary tubes makes it possible for the melt channels in embodiments to have a length-to-diameter ratio of greater than or equal to 20. The melt channels can in particular have a length-to-diameter ratio of greater than or equal to 35, greater than or equal to 50 or greater than or equal to 60.

The nozzle device can in principle be designed according to the Exxon principle. In particular, the melt nozzle can be a melt nozzle for a nozzle device according to the Exxon principle, but instead of holes Ka pillar pipes are used.

The nozzle device can be set up so that the one or more gas ejection openings result in a sheet-shaped or blade-shaped gas ejection, namely under an angle greater than 0 ° to the ejection direction of the melt. Gas ejection openings can in particular generate converging, for example sheet-shaped or blade-shaped, gas ejections.

The gas blowing, in particular air blowing, through the at least one gas channel is preferably carried out at an angle to the flow direction of the melt channel through its mouth, which is different from zero degrees. The angle can, for example, from 25 ° up to and including 35 °, in particular about 30 °, betra conditions. If the melt, which passes through the arrangement of the capillary tubes, is exposed to air from two sides through two air ducts, the angle is in where the air is blown in to the flow direction of the melt channel, preferably the same from both sides, for example 30 ° in each case.

The walls of the melt nozzle can, for example, converge or have converging wall surfaces which meet one another in the output section or on the output side of the nozzle body at the tip thereof. The wall surfaces can, for example, enclose an angle of two times about 30 °, i.e. about 60 °.

The method according to the invention for producing a nozzle device, as described herein, has at least the provision of a nozzle body with one or more receiving channels and the arrangement of capillary tubes in the one or more receiving channels. The receiving channels are preferably closed around the capillary tubes. For fastening the capillary tubes in the receiving channels, the following can be considered in particular: press fit, welding, gluing, soldering. The soldering type of fastening is particularly advantageous because it allows the formation of long connections and thus large-area connections between allow the capillary tubes and the walls of the receiving channel or channels.

The known method of diffusion soldering has proven to be particularly advantageous for fastening the capillary tubes in the one or more receiving channels. This leads to an intermetallic phase with a melting temperature of the connection which is higher than that of the solder. This makes cleaning by bakeout possible even at very high temperatures, or the temperature during the cleaning process does not have to be controlled as precisely.

Before soldering, the capillary tubes are preferably closed at least on one side, preferably closed on both sides. The capillary tubes can be closed for example se by welding, in particular laser welding. This means that solder cannot run into the capillary tubes during soldering. The capillary tubes are preferably filled in order to prevent the entry of impurities into the capillary tubes when the capillary tubes, which are closed at least on one or both sides, are reopened.

[0026] Further features and embodiments emerge from the subclaims, the following description and the figures. It shows by way of example:

Figure 1 - a meltblow device in a schematic, partially sectioned view,

Figure 2 - an enlarged view of a section of the representation of the nozzle device according to Figure 1 in the area of the mouths of the melt and gas channels,

FIG. 3 - an even further enlarged view of a section of the representation of the nozzle device according to FIG. 2, Figure 4 - a melt nozzle in a plan view of the output side,

FIG. 5 - a view largely corresponding to FIG. 3 of a nozzle device according to the invention with capillary tubes in the melt nozzle which form melt channels,

Figure 6 - a plan view of an output side of a melt nozzle with several capillary tubes in each one receiving channel,

Figure 7 - a plan view of an output side of a melt nozzle with several capillary tubes in a gap-like receiving channel,

Figure 8 - a plan view of an output side of a melt nozzle with several rows of capillary tubes in a gap-like receiving channel,

FIG. 9a - an embodiment with melt channels in the flanks of a melt nozzle in a sectional view,

FIG. 9b - a highly schematic plan view of a section of the melt nozzle according to FIG. 9a,

FIG. 10 - a flow chart of a method according to the invention,

Figure 11 - a partial sectional view through a capillary tube with a closed end and a filler in the interior,

FIG. 12 shows a sectional view through a melt nozzle with a capillary tube arranged therein, closed at both ends, and filler contained therein, and FIG FIG. 13 - a sectional view through the melting nozzle according to FIG. 12 after the closure of the ends of the capillary tube has been removed.

Figure 1 shows an example of a meltblow device 10. The meltblow device 10 has a tray 11, an extruder 12 for melting a plastic, usually a plastic granulate, and a connected spinning pump 13 for supplying the melt ze to a nozzle device 14. The nozzle device 14 can, for example, have a melt distributor, melt filter and various temperature and pressure sensors, without these being shown in detail. The nozzle device 14 also has a melt nozzle 15 and a device 16 with at least one, preferably at least two, channels 17, 18 for applying air to the expelled melt. The melt nozzle 15 can form a section of one or more channels of the device 16 for the application of air. In other embodiments, the channels 17, 18 are to be acted upon

Air is arranged in one or more bodies, which are separate bodies from the melt nozzle 15, which all things can be attached to the melt nozzle 15.

The nozzle device 14 shown in Figure 1 belongs to a type of nozzle device 14 that go back to an invention by Exxon. This type of Düsenein devices 14 is therefore often described as operating on the Exxon principle.

FIG. 2 shows a detail (see box with dashed lines in FIG. 1) of the view according to FIG. 1. FIG. 3 shows a detail of the view according to FIG. 2. As FIG. 2 shows, the melt nozzle 15 is approximately prismatic in cross section . The melt nozzle 15 has two walls 19, 20 on. Between the walls 19, 20 there is usually a melt distribution channel 21, from which melt channels 22 have an opening on an output side of the melt nozzle

22 go out. The walls 19, 20 have outer surfaces 24, 25 which meet in the approximately strip-shaped output side 26 of the melt nozzle 15. The walls 19, 20 form a discharge point 27 of the melt nozzle 15 due to the tapering position of the walls 19, 20.

In known melt nozzles 15, melt channels 22 can be formed by capillary bores. The Kapil larbohrungen, melt channels 22 or openings or Mündun gene 23 in the output side 26 are usually arranged in a row one behind the other. The melt channels 22 usually have internal diameters in the range of 0.2-0.4 mm and have a length-to-diameter ratio L / d of 5-15. The capillary bores have a constant diameter or cross section.

The meltblow device 10 has a device 16 for applying an air stream to the melt emerging from the mouths 23 of the melt channels 22. This device 16 has two devices referred to as air cutting. These are formed by at least two air channels 17, 18, which can be hit with air beauf. The air ducts 17, 18 are on either side of the arrangement 30, for example one or more rows, of mouths

23 of the melt channels 22 are arranged. The air channels 17, 18 are each assigned to the arrangement 30 of mouths through which the melt emerges from the melt nozzle 15. Each air duct 17, 18 has an elongated mouth 31, 32 which extends along the arrangement 30.

The melt nozzle 15 can be set back slightly with respect to the mouths 31, 32 of the air cutting edges (offset V). The narrowest cross-section of the construction for the exiting primary air thus forms the exit gap 33 at the end of the dispensing tip 27. In the exit gap 33, the primary air has the maximum flow velocity. According to the Exxon principle, the melt expelled from the melt channels is blown at an angle of approx. 60 ° (2 x 30 °). In particular, an angle in the range from 50 ° (2 x 25 °) up to and including 70 ° (2 x 35 °) inclusive is possible. The angle a (e.g. 60 °) is enclosed by imaginary center lines 47, which are imagined lying in the cross-sectional plane of the melt nozzle 15, each in the middle between the wall surface 24, 25 of the wall 19, 20 of the melt nozzle 15 and the opposite further surface which bounds the air duct 17, 18 with the wall surface 24, 25. The center lines 47 are given symmetrically to the center line 41.

In the meltblow process, the plastic granulate is melted in the extruder 12 and continuously fed to the nozzle device 14 via the spinning pump 13. The polymer melt extruded from the melt nozzle 15 is released from the air ducts 17, 18 immediately after it emerges from a converging, tempered air stream

- the so-called primary air - which mixes with the ambient air - the so-called secondary air - immediately after the nozzle exits. The fibers that form from the melt cool on the way to the tray 11 and are caught as intertwined fibers in the form of a nonwoven fabric 34. The filing takes place mostly on an air-permeable structure 11, such as on a From position belt 11 or on a sieve drum 11, which is also provided with a vacuum. This serves to keep the fibers on the shelf 11 and to remove excess primary air.

The capillary bore density and the melt penetration rate are decisive factors for the economic operation of a meltblow device 10.

Capillary bores with diameters in the range of d = 0.2-0.4 mm can generally only be made up to a length of a maximum of twenty times, i.e. 20 d, the diameter. As a rule, melt nozzles with a length-to-diameter ratio of 8 to a maximum of 15 are produced. A larger ratio of length to diameter than 20 cannot be produced with the necessary precision by drilling with such fine diameters. A small melt channel diameter leads to a necessarily slim design of the walls 19, 20 or legs of the melt nozzle 15, since the melt channel cannot be manufactured with any length. This is associated with a thin design of the walls 19, 20 at their most sensitive point. As a result, an Exxon nozzle with drilled melt channels 22 can be subjected to a maximum pressure of 30-50 bar. The polymer throughput (g / h / min = grams / hole / minute) generates a corresponding internal pressure. For the finest fibers, produced with the smallest capillaries, the productivity (g / h / min) is therefore limited.

To solve this, a receiving channel 35 is made with a larger transverse dimension than a capillary bore according to the prior art, and this receiving channel 35 or at least a portion of this receiving channel 35 is filled with a capillary tube 36 or several (at least two) capillary tubes 36 . Each capillary tube 36 with its tube channel forms a melt channel 22. Capillary tubes 36 can be manufactured in almost any length over a wide range of diameters and wall thicknesses. Since the capillary tubes 36 can have very small Kapillarrohrin n diameters. For example, the cap- Larrohre 36 have an inner diameter of 0.1 millimeters up to and including 0.5 millimeters or a diameter of less than or equal to 0.1 millimeters. The length-to-inner diameter ratio can, in embodiments, be greater than or equal to 15 or more, for example greater than or equal to 20 or more.

Using capillary tubes 36, for example, melt channels 22 including mouths 23 can be generated which have an internal diameter of less than or equal to 500 micrometers, less than or equal to 400 micrometers, less than or equal to 300 micrometers, less than or equal to 200 micrometers , less than or equal to 100 micrometers or less than or equal to 75 micrometers, for example 50 micrometers. The length-to-diameter ratio of the melt channels can be, for example, greater than or equal to 15 or more, for example greater than or equal to 20 or more. In particular, the length-to-diameter ratio can be greater than or equal to 35, greater than or equal to 50 or greater than or equal to 60. Such melt channels 22 could not be produced by means of drilling.

Essential advantages of the invention are the ability to manufacture ultrafine fibers and / or fibers with high productivity due to possible high pressures and thus high throughputs. According to the invention, the length of the melt channel or the capillary tube can be, for example, 5-10 times greater than usual. The thickness of the wall 19, 20 at the most sensitive point can, for example, be up to two to three times greater than in known melt nozzles 15. This can increase the tolerable internal pressure and the polymer throughput by, for example, up to two to three times. For example, the nozzle device 14 can be designed to be stable in such a way that the melt pressure in the melt distribution channel 21 or each melt channel 22 is at least 60 bar, particularly preferably at least 100 bar may have. This leads to a correspondingly higher productivity, for example up to two to three times as much. Furthermore, an increased length of each of the melt channels 22 up to the mouth 23 enables an improved uni formity of the fibers with one another.

For illustration, FIG. 4 shows an exemplary view of the strip-shaped output side 26 of the melt nozzle 15 of the exemplary embodiment according to FIGS. 1 to 3, in which the melt channels 22 open.

FIG. 5 shows a representation corresponding to FIG. 3 of a cross section through a meltblow device 10 with a melt nozzle 15 according to the invention. The above description of FIGS. 1 to 3 and their representation can be used for the exemplary embodiment according to the invention according to FIG can be used. As can be seen in the illustration, however, in contrast to the melt nozzle 15 according to FIGS. 1 to 3, a capillary tube 36 is arranged in the melt nozzle 15, which instead of a capillary bore forms a melt channel 22 and preferably also its mouth 23 for dispensing melt. This capillary tube 36 has a larger length-to-inner diameter ratio than the capillary bore shown in FIG. 3.

In addition, in preferred embodiments according to the invention, there is no air duct 17, 18 which would surround a certain capillary tube 36, but not another, or which would surround a certain group of capillary tubes 36, but no other.

As can be seen from the figure, the walls 19, 20 in the exemplary embodiment according to FIG. 4 have a greater thickness at points of the melt nozzle 15 that are decisive for stability, in particular pressure stability, than the corresponding corresponding walls 19, 20 of the melt nozzle 15 according to FIG. 3.

The cross section of the capillary tube 36 can in particular have a round, in particular circular, outer contour and a round, in particular circular inner contour. In principle, it would be possible to use capillary tubes 36 with a cross-sectioned inside and / or outside at least partially polygonal contour, but this is not preferred because of the manufacturing effort and the costs of such capillary tubes.

Figures 6 to 8 show schematically a plan view of strip-shaped output sides 26 of exemplary embodiments of the invention.

In one embodiment, capillary tubes 36 are introduced at a distance from one another in discretely arranged receiving bores, which form receiving channels 35. An example of this is illustrated in FIG. On the receiving channel 35 between the capillary tube 36 and the inner wall surface 37 of the receiving channel 35 is closed. The receiving channel 35 between the capillary tube 36 can be filled with solder, for example, and / or the area between the receiving channel 35 and the capillary tube 36 can have a thickness of zero due to a press fit, so that the receiving channel 35 between the capillary tube 36 and the inner wall surface 37 of the Receiving channel 35 is closed.

Embodiments are possible in which, as an alternative or in addition, capillary tubes 36 are arranged in a row one behind the other in a gap-shaped receiving channel 35. An example is illustrated in FIG.

The thickness of the wall 19, 20 of the capillary tubes 36 can, in exemplary embodiments, be the limiting factor for the line density of the holes. Holes per inch (hpi) is common.

A particularly high line density can be achieved by using particularly thin-walled capillary tubes 36. Alternatively or additionally, capillary tubes 36, as illustrated in FIG. 8, can be arranged in a gap-shaped receiving channel 35 in at least two or more rows 38, 39, 40 of capillary tubes 36. In FIG. 8, for the sake of clarity, not every capillary tube has a reference number 36 and not every melt channel has a reference number 22. The capillary tubes 36 of a row 38, 39 or 40 can be connected to the capillary tubes 36 of the adjacent rows 38, 39 or 40 in the longitudinal direction of the row 38 , 39 or 40 be offset, for example by half the distance between two center lines 41 of two adjacent capillary tubes 36, which center lines 41 are thought to extend centrally through the capillary tubes 36. Center lines 41 for selected capillary tubes 36 are each illustrated with a point. In the embodiment according to Fi gur 8, for example, three rows 38, 39, 40 of Kapil larrohren 36 are arranged side by side. The capillary tubes 36 of a row 38, 39 or 40 are offset from the capillary tubes 36 of each adjacent row 38, 39 or 40. Alternatively, in exemplary embodiments, only two rows can be arranged next to one another, for example. For example, two rows side by side with capillary tubes 36 in a row, which are offset from the capillary tubes 36 of the other row in Rei direction.

A relatively high line density of melt channels 22 or orifices 23 can also be achieved by means of such embodiments. The line density can be determined here by determining the number of capillary tube orifices 23 or capillary tube center lines 41 along a straight line L or line and on the straight line or line of straight lines which line is never L or route are through the centers of the Mün applications 23, through a center point of the mouth 23 and perpendicular to a center line or the center lines 41 extends perpendicular right intersecting. The straight sections of the line stretch from center to center and / or center line 41 to center line 41, perpendicular to center line 41.

Alternatively or additionally, one or more rows 42, 43 of capillary tubes 36 can be arranged in one or at the walls 19, 20 of the melt nozzle 15 next to the linear output side 26, which is arranged at the end of the output tip 27 of the melt nozzle 15 is. An embodiment with rows 42, 43 of capillary tubes 36 arranged in the flanks of the dispensing tip 27, which rows 42, 43 extend parallel to the one or more rows 38, 39, 40 in the dispensing side 26, is illustrated in FIG. FIG. 9a shows in cross section an example of a melt nozzle 15 according to the invention with capillary tubes 36 arranged in the output section on the output side 26, which form melt channels 22 for the output of melt, and melt channels 22 in the walls 19,

20 of the nozzle body of the melt nozzle 15, the melt zekanäle in the walls 19, 20 next to the one or more rows of channels 38, 39, 40 are arranged in the output side 26 and open on the outer surfaces 24, 25. As illustrated in FIG. 9a, the ends of the capillary tubes 36, which form the melt channels 22 in the walls 19, 20 of the nozzle body of the melt nozzle 15, preferably end with the outer surfaces 24, 25. Otherwise, the end surfaces of the capillary tubes 36 can be arranged at right angles to the longitudinal direction of extension of the capillary tubes 36 in the walls 19, 20. The capillary tubes 36 preferably do not protrude beyond the wall surfaces 24, 25 in order not to obstruct the flow of air. FIG. 9b schematically shows a top view of the output side 26 of the melt nozzle 15 according to FIG. 9a. The melt channels 22 in the walls 19, 20 can also be formed by arranging one or more capillary tubes 36 in one or more receiving channels 35. For the sake of clarity, not every capillary tube has a reference number 36 and not every melt channel has a reference number 22. By means of the solution described, a high density of melt channels 22 measured along a line L can be achieved. The line density can be determined in the same way as explained in connection with FIG. 8.

However, in embodiments, a high line density is always provided - for example as explained above - this is preferably at least 30 holes per inch to at least 50 holes per inch or more.

As part of an exemplary method 100 (see FIG. 10) for producing a nozzle device 14 according to the invention or a melt nozzle 15 according to the invention, a nozzle body for a melt nozzle 15 is provided (instruction 101 in FIG several recording channels 35 contains. The recording channels 35 can be taken gefer by a conventional technique. For example, receiving channels 35 can be drilled and / or eroded. Due to the relatively large diameter or the relatively large width, long receiving channels 35 can be produced.

Capillary tubes 36 are arranged in the one or more receiving channels 35 in the nozzle body (instruction 102) and fastened there (instruction 102). The fastening term 102 can be done by press fitting, gluing, welding, but preferably by soldering. A long connection and thus a large-area connection can be made by means of soldering 102 be created between the capillary tube 36 and the nozzle body. The soldering of the capillary tubes 36 is preferably carried out in a vacuum, preferably by diffusion soldering. A diffusion soldering process is listed, for example, under the designation "diffusion brazing (in the furnace)" in Table 2 of the standard DIN EN 4632-001, Table 2. This creates an alloy between solder and base material that has a much higher melting point than the solder material. This results in very good strength at high temperatures. During soldering 103, for example by diffusion hard soldering, but also, for example, when gluing in, it must be ensured that solder or adhesive does not get into the capillary tube 36. to prevent the interior of the capillary tubes 36 from being clogged or contaminated.

One possibility to prevent this is to close the capillary tube 36 before insertion or at least before soldering at one end 44 or at both ends 44, 45 of the capillary tube 36 (instruction 102 ″). For example to be welded, in particular to weld by means of a laser. FIG. 11 shows, in a longitudinal section, a section of a capillary tube 36 with an end 44 closed by welding.

The closure of the end 44 must be opened again after fastening (instruction 104). This can be done, for example, by erosion, in particular die sinking. To open the closures at one end 44 or both ends 44, 45, the end 44 or ends 44, 45 can be severed. When opening 104, the capillary tube 36 can be shortened in such a way that the remaining capillary tube 36 has a length that is at most twice the length of the receiving channel 35 of the melt nozzle 15 produced. In the course of opening 104 the Closure, the final contour of the melt nozzle 15 can be produced by erosion.

When removing 104 the closure, care should ideally be taken to ensure that dirt cannot get into the capillary tube 36. By means of the erosion process described above, for example, the finest metal removal could get into the capillary closed by the capillary tube 36. This metal removal can only be removed with difficulty. The "uncovering" of the capillaries requires a high level of manpower. The prevention of soiling can be done, for example, by filling the capillary tube with a subsequently removable substance 102 '. For example, before welding 102 ″ of one or both ends 44, 45. The substance can be wax or waxy, for example. The substance can be removed by heating 105 the melt nozzle 15. Figure 11 shows an example that the interior of the capillary tube 36 is filled with a filler 46 that prevents a Contamination which cannot be removed from the capillary tube 36 or can only be removed with considerable effort from the capillary tube 36, when removing the closure at one end 44 or both ends 44, 45 enters the interior of the capillary tube 36, which forms the melt channel 22 should.

FIG. 12 shows in cross section a nozzle body in which a filled and closed capillary tube 36 is inserted. FIG. 13 shows the embodiment according to FIG. 14, in which the closures of the two ends 44,

45 are removed, but the filler material 46 is still contained in the capillary tube 36.

The manufactured nozzle device 14 can be subjected to a melt pressure of, for example, at least 60 bar or even at least 100 bar. The nozzle device 14 is provided for the production of a random fiber product 34 with a melt nozzle 15 with an arrangement 38, 39, 40 of several melt channels 22. The nozzle device 14 has a gas channel 17, 18 with an orifice 31, 32, which is assigned to a plurality of melt channels 22 of the arrangement 38, 39, 40. The gas channel 17, 18 is set up to generate a gas ejection which detects the melt ejected from the melt channels 22, the melt nozzle 15 having an arrangement of capillary tubes 36 to form the melt channels 22. The receiving channel 35 is gap-shaped. The capillary tubes 36 are net angeord in the receiving channel 35, wherein the capillary tubes are arranged in the receiving channel 35 except in at least two rows.

The nozzle device 14 can have a gas channel 17,

18 with a mouth 31, 32, which is assigned to a plurality of melt channels 22 of the arrangement 38, 39, 40. The gas channel 17, 18 is set up to generate a gas ejection which detects the melt ejected from the melt channels 22. To form the melt channels 22, the melt nozzle 15 has an arrangement of capillary tubes 36 arranged in a nozzle body. The nozzle body has walls 19, 20, the ends of the capillary tubes 36, which form the melt channels 22 in the walls 19, 20 of the nozzle body of the melt nozzle 15, each terminating with one of the outer surfaces 24, 25. Such capillary tubes open into only one of the outer surfaces and as a result have a flat, elliptical mouth. Alternatively, the end surfaces of the capillary tubes 36 are arranged at right angles to the longitudinal direction of extension of the capillary tubes 36 in the walls 19, 20 and do not protrude beyond the wall surfaces 24, 25. The mouths of these capillary tubes are flat and circular. The capillary tubes 36 of one row can be offset from the capillary tubes 36 of an adjacent row.

The capillary tubes 36 can be arranged in one or more receiving channels 35, the one or more receiving channels 35 being closed around the capillary tube or tubes 36. A receiving channel 35 can be provided for each capillary tube 36.

The receiving channel or channels 35 can have a length which is at least half as great as the length of the capillary tube 36.

The capillary tubes 36 can have an inner diameter of less than or equal to 500 micrometers, less than or equal to 400 micrometers, less than or equal to 300 micrometers, less than or equal to 200 micrometers or less than or equal to 100 micrometers, for example 50 micrometers.

The capillary tubes 36 can form melt channels 22 with a length-to-diameter ratio of greater than or equal to 20, greater than or equal to 35, greater than or equal to 50 or greater than or equal to 60.

The nozzle device 14 can be designed for an application of pressure to output the melt of 60 bar or more, preferably of 100 bar or more.

A nozzle device 14 according to the invention for producing a random fiber product 34 has a melt nozzle 15 with an arrangement 38, 39, 40 of several melt channels 22. The nozzle device (14) has egg NEN gas channel 17, 18 with an orifice 31, 32, which a plurality of melt channels 22 of the arrangement 38, 39, 40 is assigned, wherein the gas channel 17, 18 is set up to generate a gas ejection which detects the melt ejected from the melt channels 22. In accordance with the invention, the melt nozzle 15 has an arrangement of capillary tubes 36 to form the melt channels 22. A method 100 according to the invention for producing a nozzle device comprises providing 101 a nozzle body 15 with one or more receiving channels 35 and arranging 102 and fastening 103 capillary tubes 36 in the one or more receiving channels 35.

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Claims

Patent claims:

1. Nozzle device (14) for producing a tangled fiber product (34) with a melt nozzle (15) with an arrangement (38, 39, 40) of several melt channels (22), the nozzle device (14) having a gas channel (17,

18) with a mouth (31, 32) which is assigned to a plurality of melt channels (22) of the arrangement (38, 39, 40), the gas channel (17, 18) being set up to generate a gas output which the Detects melt ejected from the melt channels (22), characterized in that the melt nozzle (15) has an arrangement of capillary tubes (36) to form the melt channels (22).

2. Nozzle device (14) according to claim 1, wherein the capillary tubes (36) are arranged in one or more receiving channels (35), wherein the one or more receiving channels (35) to the or the capillary tube (36) are closed GE.

3. Nozzle device (14) according to one of the preceding claims, wherein each capillary tube (36) has a receiving channel

(35) is provided.

4. Nozzle device (14) according to one of claims 1 to 3, wherein the receiving channel (35) is gap-shaped and where the capillary tubes (36) in the receiving channel (35) are arranged.

5. Nozzle device (14) according to claim 4, wherein the capillary tubes are arranged in the receiving channel (35) in one or more (at least 2) rows.

6. nozzle device (14) according to any one of the preceding claims, wherein the one or more receiving channels (35) a Län- ge that is at least half as large as the length of the capillary tube (36).

7. Nozzle device (14) according to one of the preceding claims, wherein the capillary tubes (36) have an inner diameter of less than or equal to 500 micrometers, less than or equal to 400 micrometers, less than or equal to 300 micrometers, less than or equal to 200 micrometers or less than or equal to 100 micrometers , for example 50 microns.

8. Nozzle device (14) according to one of the preceding claims, wherein the capillary tubes (36) melt channels (22) with a length-to-diameter ratio of greater than or equal to 20, greater than or equal to 35, greater than or equal to 50 or greater or equal 60 form.

9. Nozzle device (14) according to one of the preceding claims, wherein the nozzle device (14) is designed for a pressure application to output the melt of 60 bar or more, preferably of 100 bar or more.

10. melt nozzle (15) for a nozzle device (14) according to one of the preceding claims.

11. The method (100) for producing a Düsenein direction (14) according to any one of claims 1 to 10, aufwei send: providing (101) a nozzle body (15) with one or more receiving channels (35) and arranging (102) and fastening ( 103) of capillary tubes (36) in the one or more receiving channels (35).

12. The method (100) according to claim 11, wherein the Ka pillarrohre (36) in the one or more receiving channels (35) are soldered.

13. The method according to claim 12, wherein the capillary tubes (36) are soldered in the one or more receiving channels (35) by means of diffusion soldering.

14. The method (100) according to claim 12 or 13, wherein the capillary tubes (36) are closed on at least one side (102 ″) prior to soldering (103), for example by means of laser welding.

15. The method (100) according to claim 14, wherein the Ka pillarrohre (36) are filled in order to prevent the entry of Verun cleanings into the capillary tubes (36) when reopening (104).