DE1950669B2 - METHOD AND DEVICE FOR THE MANUFACTURING OF FLEECE - Google Patents

Description

The invention relates to a method for producing a thread fleece by spinning out a multiplicity of continuous filaments made of synthetic polymer and depositing the same on an air-permeable movable one Pad and a device for this.

Staple fiber fleeces are known and widespread. The manufacture of fleece from continuously spun Threads offers the advantage of a simpler and faster method of production, in which the spinning process and the nonwoven manufacturing process by spinning the polymer melt into threads that directly are deposited as a fleece, can be combined with one another. The production of such fleeces However, the previous technology has repeatedly caused difficulties in that the threads during of spinning and filing had the tendency to maintain their spinning parallelism and sticking together like a rope To form structures that have an undesirable irregularity with respect to the nonwoven Appearance and strength given. In order to produce wider thread webs, it is also necessary that Length to form adjacent individual webs, and the strength and evenness of the overall web depends largely on neighboring or overlapping parts.

U.S. Patents 3,338,992 and 3,341,394 It has been proposed to remedy the above-mentioned disadvantages of combining the threads into rope-like To avoid structures by applying an electrostatic of the same name to the threads to be deposited Charge is applied which repels them from one another, so that each individual thread is separate from the other and avoiding parallel frets! enters the fleece. An attempt is made here a greater uniformity through a completely confused distribution and an avoidance of parallelism of the Achieve solitary threads. In this process, the threads must be electrostatically charged, which is difficult and prone to failure. This also limits the production speeds, and the nonwovens do not achieve the strength

ίο of fleeces with parallel bundles of threads.

In another known procedure (USA.-

Patent 3 402 227) the threads were after

Spinning at top speed through one

Air d-'ise sent to pull it off, to stretch it and lay it down as a tangled fleece on a moving belt. To make a fleece in practical use To produce width, adjacent individual webs were made from a number of air nozzles filed. In doing so, these air nozzles were one after the other

Arranged obliquely offset over the entire width of the storage conveyor belt in order to avoid an overlap of the to reach individual stages swept over by the nozzles. However, this resulted in stratification or Layer formation in the fleece because the threads of the

Neighboring lane were only deposited when one lane had already been deposited. This allowed the threads of adjacent webs do not penetrate, which is detrimental to the strength of the fleece impacted.

The object of the present invention is therefore to create a method that has the previous disadvantages avoids and the production of a continuous thread fleece from synthetic polymer at as possible allows high production speeds, while maintaining the uniformity of the fleece properties and avoids twisting the threads with one another.

The aim of the process is to create a fleece in which the individual threads come together in groups Form loops and loops. This is done according to the invention in that the spinnerets leaving threads are combined into thread bundles of 15 to 150 threads and each Thread bundles through a previously proposed take-off nozzle, in which the propellant flow at supersonic speed is brought, stretched and opened up in sub-bundles that the thread bundle overlap each other when they are deposited and which consist of essentially parallel individual threads Sub-bundles mutually form loops oriented in any way.

The one proposed in German Offenlegungsschrift 1 785 158 can be used as a corresponding extraction nozzle Nozzle can be used. The fleece produced in this way is characterized by its great thickness and Uniformity compared to previously known fleeces. In the method according to the invention is a Nonwoven web through the simultaneous spinning of a large number of continuous filaments made from synthetic polymer manufactured. The spinning takes place in the usual way from the melt, with z. B. the Melt of the polymer from a plurality of downwardly directed and preferably in one or is extruded several rows of arranged spinnerets. During the spinning, the threads become in a straight row next to each other and at an even distance from each other, non-rotated Bundle with at least 15, preferably

but 50 to 150 threads, combined. Each of these bundles is pulled down simultaneously at a speed of at least 3000 m / min, preferably 3500 to 8000 m / min, in gas jets running at supersonic speed and directed so that it hits a substantially horizontal shelf. The bundling of the threads into bundles, their withdrawal and their impact on the withdrawal belt is carried out in that each bundle is sent through a withdrawal nozzle in which the threads are enveloped with c <τ \ air jet, which with '.: Bcrschallgeb. windiness shoots down. The draw-off nozzles are above the shelf in a straight, perpendicular to the direction of movement of the tray being rich - cr series arranged so that the chlossenen in the gas jet a-JX bundle on impact with the in H to iv in a line \ vegung laydown belt located '.'. .v. Row at right angles to the transport direction of the A! ! uge extend. The shelf can be a customary A'.iliiüc, as used in non-woven technology \ i> <M, z. B. a sieve designed as an endless belt ■! ■■ ·.! or a sieve drum.

') they consist of a number of threads running in parallel Bundles of threads are placed on the tray in a st:. ■ ' '.-π loops over the entire width of a E; i "clbahn, as shown by the impact of the air stream defined by a single air nozzle, extend back and forth. Before and when the Filing is parallel-sounding thread bundles in I split up the bundles, the only small numbers of them! have parallel running threads and form secondary, i.e. smaller loops and loops, not only to each other, but also to neighboring ones Linzel webs overlap and thus an essentially complete mixing with the overlapping Achieve dividers of the neighboring individual tracks. The deposited thread bundles then form a gliding endless thread fleece, which by compressing. Heat sealing, needling or treating with one Binders, such as. B. latex or other treatment methods known in non-woven technology can be solidified and stabilized.

The filaments resulting from the present invention are oriented, crystalline, or crystallizable Threads made from any thermoplastic polymer that allows melt spinning, e.g. B. Polypropylene, polyamide and polyester.

In the following, exemplary embodiments of the invention are described in conjunction with the drawings described in more detail. It shows

1 shows a schematic representation of the manufacture of the fleece according to the present invention,

2a shows the schematic representation of the fine structure of deposited sub-bundles into which the The thread bundle is divided,

2b shows the reproduction of a microphotograph of a nonwoven web produced according to the invention with the connection points between the sub-bundles,

F i g. 3 shows an example of a previously proposed air or extraction nozzle in cross section.

According to FIG. 1, thermoplastic material is fed into extruder 100 , melted and extruded. The extruder is driven by a motor 101. The extruded material is fed into the VieHoch spinneret 110 by means of a pump 103. The threads that are formed are drawn off through a nozzle 121 which is continuously fed with pressurized air through the inlets 22a. In the nozzle 1 21, the pressure gas flows substantially parallel to the emerging from the guide pipe threads without impinging on them so that they do not mix, but rather flow completely separate. More precisely, the pressurized gas flows in such a way that the threads spread apart and sub-bundles also run essentially in parallel

ίο form threads. The sub-bundles thus formed then strike the depositing conveyor belt 131 , which moves on rollers 141 . A guide plate 104 is located between the outlet of the nozzle 121 and the tray 131. A suction chamber is located below the tray belt

is arranged 105 , in which the air blown onto the shelf 131 is at least partially sucked off. The guide plate 104 is part of the suction chamber and improves its suction effect. After being deposited, the fleece runs through the pair of spinning rollers 151.

The spinning direction can be found at a speed of 0.1 to 15g per nozzle per Minute. Useful equipment includes a number of downwardly directed spinnerets, extrude the molten polymer

and shape the desired threads. The spinnerets are expediently arranged in one or more rows parallel to the bank of air nozzles which extend in a row across the tray 131 which is in motion. Optionally, each multi-hole spinneret 110 produces at least a sufficient number of threads for each a draw and air nozzle, ie at least 15 and preferably 50 to 150 threads, although it is more common for a single multi-hole spinneret to load a plurality of draw nozzles 121

supplies. So z. B. spinnerets with 200 to 1000 orifices can be used.

The spinneret outlet openings have a diameter of 0.1 to 1.5 mm, preferably from 0.3 to 1.2mm to produce typical thread sizes.

The throughput of liquid polymer is generally 0.5 to 1.5 g, min per outlet opening. The spinning temperature is usually 250 to 350 C, which depends on the polymer that is extruded. The extruded threads are with cooling air chilled.

The threads produced in the spinning machine are preferably cut to a thickness of about 10 to 50 microns, i.e. in the textile design area, stretched. The threads can, for. B. a titer between about I and 20 denier, although threads with a lower or higher denier depending on the desired end product can be used. So one would go to the formation of a fleece for the manufacture of a Textü-like Fulienmaterials threads with a denier of 1 to 10, for the production of a paper-like However, use 3 to 12 denier filaments for sheeting. For thicker products such as z. B. Carpet underlayment, thicker threads with a titer of 5 to 20 are used. The crazy ones Threads generally have an elongation at break or tear at break but 80% and tensile strength or tear strength over 2.5 g / den, d. H. from 3 to 7 g / den.

The threads spun in this way become a straight line of juxtaposed bundles with

at least 15 threads each, but preferably 50 to 150 threads, combined, stretched in an air or exhaust nozzle according to FIG. 3 and at high speeds from at least 3000 to 8000 m / min

5 6

deducted. The air common pressure media used for this purpose, which are used to supersonic nozzles are expansion or exhaust nozzles. A speed expand and Mach numbers until such an air nozzle has a nozzle part through which 3.5 and more in a flow either parallel neck primary compressed air evenly with supersonic to the thread direction and slightly oblique to the thread speed in an outwardly diverging 5 direction. In doing so, an angled expansion chamber is expanded. A guide beating of the compressed gas on the threads in the general pipe for threads and secondary suction air extends through a suitable construction of the eccentric expansion chamber through the neck and the expansion chamber in relation to the guide tube, up to a discharge tube with a constant passage from which the threads emerge , avoided. Especially knives. The primary compressed air flows essentially io more of the expansion chamber 17 parallel to the mende propellant flow exiting from the guide tube should not have any flow component threads without meeting them, ie without having to mix and match to the axis of the guide tube 4 Twisting of the threads takes place. To avoid twisting the threads to be withdrawn, rather flows in such a way that a good distance is maintained. The pressure medium is preferably cold or warm and preferably an expansion of the bundle and air, but steam or other media can also be subdivided into sub-bundles with parallel use Find. Generally the ingress of running threads is allowed. This means that the pressure of the compressed gas is 10 to 50 atmospheres. Another essential parallelism between the threads within the description of useful air nozzles can be found in half of the thread emerging from the exhaust pipe in German laid-open specification 1 785 158.
alliance reached. a ° A thread bundle or sub-bundle which splits into further smaller subdivisions is shown in FIG. 3 shown. This consists of the bundle, which then bounce back, and a vortex air nozzle consisting of an upper part 2 which is screwed into a lower part 1 layer of intermingling bundles and sub-bundles. The upper part 2 is home to as form, Jie are then stored. At the over-conical filling funnel 3 for the threads and the lapping points, vortex threads are linked adjacent secondary air, which opens into the guide tube 4. barter air nozzles effectively to an endless, equal-This conical inlet opening 3 has an opening-like, unlayered overlapping part,
angle - »% 'on 5 to 15 °, preferably 7 Μς 11 °. to In Fi g. 2a is to help keep the threads separate during their sub-bundle α of parallel single threads passing through the nozzle. The height shown, which is divided into smaller bundles b of the inlet funnel 3 must not be greater than 40 times and of which a single thread c is in itself further-inside diameter of the guide tube part 4. Run. The sub-bundles form loops and it is usually not larger than 10 to 20 times the cross itself, for example in the area, and / or the inner diameter of the tube 4. The lower part 1 of the 35 cross other thread bundles.
The air jet device has two ring-shaped bores limited, the top to be welded into a 40-. The intersecting bundle of filaments with rounded edge 14 end, which is connected to the funnel-shaped part over the surface of the fiber fleece in a nozzle cavity 15 which follows an isotropic pattern with no preferred direction. This tapers inside to the narrowest point 16 in the neck. The thread course ensures low elongation, shape-the cavity then enlarges to the outside to become resistant and unusually high tensile strength-expansion chamber 17 and ends in a cylindrical shape. dei of the nozzle cavity 15 to the outside is shown with Win non-woven film is shown in Fig. 2b, which measured a microcule μ. However, this angle is generally photograph of such a filament nonwoven material ACCORDING 8 £ ^c to 20, preferably 10 to 15 ^C. This reproduces the present invention.
Way forms the outer wall of the guide tube 4 50. In known methods (e.g. according to USA.-Patem with the expansion chamber at point 16 a ring 3 402 227) the fleece is formed from individual webs-shaped neck through which the compressed air goes through the threads of one of the ir accelerated to the speed of sound and air nozzles arranged in a row is formed. Di «is passed on to the expansion chamber 17 below. The row of air nozzles runs at an acute angle to the opening angle of the nozzle funnel 15 is 55 direction of movement of the storage surface. It is unavoidable that stratification occurs in the process, since the ring-shaped surface between the end of the individual guide tube 4 laid down by a single air nozzle and the start of the exhaust pipe has already been laid and completely formed, before 18 (i.e. the At the end of the expansion chamber 17), the overlapping part that is then formed forms the annular cross section of the expansion zone. 60 adjacent single lane is applied. Essentially, the end of the guide tube is somewhat borrowed in known methods within de below the beginning of the exhaust pipe 18, which is formed by areas joined together by fleece structure, ii is uniformly cylindrical from top to bottom. For the present invention, a link between the adjacent assemblies of other air jet devices can also be used, provided that threads 65 are stored, so that the strength of the whole is removed at high speed and a nonwoven web becomes uneven,
Eliminate mutual influencing of the threads The present invention avoids such Schicri able. For air nozzle devices of this type, in general, the fact that for a simultaneous formation, Vei

Mixing and overlapping of thread sub-bundles, overlapped without layering by 65 to 70% loops and loops in the adjacent deposited width. The loops and loops of a single single track is taken care of. lane mixed completely with those lying on it - for this reason, the take-off nozzles are in one of the individual lanes. The weight per unit area of a straight line, perpendicular to the direction of movement of the web segment, deviated from the average weight of the row aligned with shelf 131. In the process, the entire fleece web decreases by a maximum of 7%. The resulting nonwoven web had a width of 70 cm and a certain flow path, so that the and a very uniform structure. For easier entrained threads before or immediately about handling the nonwoven web it was zw ^; between two of the shelf can penetrate. * ° Rollers lightly pressed. This slightly compressed Viies-

Bahn was then at a speed of

B is ρ ie 1 1 3 _m / min (ie at the speed of the depositing polypropylene granulate was belt in an extruder) between belt and roller of the pressure belt melted, which pulled a screw with a through machine,
knife of 45 mm and a length that was 28 times 15

was as big as its diameter. The polypropylene P

had a crystalline melting range of 160 to nylon 6 was melted in the 164 ° C described in Example 1, a density of 0.906 g / cm ³ and an extruder. The viscosity of the melt melt index; ₅ at 230 ° C from about 5 before the ex- nen material was 2.6 rel at a temperature handed down. The extrusion took place under a pressure 20 of 283 ° C. The extra pressure was 60 atm. That of 35 kg / cm ² , and the melt had a temperature multi-hole spinneret had 150 nozzle holes with a temperature of 310 ⁰ C at the exit. The spinneret diameter of 0.6 mm each. The throughput per had 300 nozzle outlets. The throughput was 0.66 g nozzle hole was 1.1 g / min. The nylon threads were released per minute. The polypropylene threads emerging from the spinneret with the air jet under the same operating conditions were drawn off under the same temperature conditions as in Example 1. The temperature is cooled to below 60 ° C and 30 individual threads are drawn off from ten air nozzles in bundles of each resulting thread take-off speed laid down nonwoven web amounts transversely to the direction of movement of the conveyor belt, the 350 g / m ² .

SlUIl 1, J III UlllClliaiU UUI l ^ u.J \ .ii t. «-.-..—, -cj «-

was. The air nozzles operated with a pressure Example 3
of 22 Atm. The air consumption was per nozzle

30 m ³ and hour. The dimensions of the air nozzles A polyester with a content of 0.4 weight was 2.0 mm Ω at the inlet tube and 4.3 mm Ω percent titanium dioxide was in an extruder at the outlet tube. The threads were melted by an air-35 and processed as follows:
current at a speed of about 520 m / sec Sninnhedinmmopii
pulled through the air nozzles. The air nozzles oscillated spinning conditions.

with a frequency of 2 Hz. The take-off speed extruder 45 mm 0;

length of the thread entrained by the air flow length 126 cm (28 d]

carried 4000 m / min, which resulted in a titer of 1.5 den. 40 multi-hole spinneret 300 nozzle outlets

The strength of the threads with 1.5 the amount 4.3 g / den. Spinning temperature 275 ° C

The weight per unit area of the laid nonwoven web was in air nozzles

85 g / m ² , which corresponds to a throughput speed of the number of air nozzles .... 10

10.8 kg / h corresponded. The storage and conveyor belt throughput 1.1 g per nozzle outlet

was at a rate of about 3 m / min ^and 45 min

moved forward. The continuous threads were swiftly drawn off the thread

conveyor belt in motion 4500 m / min

blown overlapping sub-bundles, each riter 2.2 denier

three to five essentially parallel threads of air pressure

and formed a nonwoven web. The 50 _{mr the} air jets .... 25 atm.

The nonwoven web produced consisted of a large number of lateral inner diameters

side-by-side longitudinal individual strips made of poly- the air nozzle? S mm

propylene threads which are smaller in the form of sub-bundles f ° ^r Lfftduse 2.5 mm

with essentially parallel threads in outer diameter

loop-like arrangement on the single track in 55 of ^the air nozzle 5.0 mm

a width of 0.25 m with a thread length of basis weight 100 g / m ²

5 m and distributed back and forth over a single track in a loop-like arrangement to multiply The nonwoven web thus produced and stored b <overlapping secondary smaller loops and a temperature of 102 ⁰ C and under geringei loops has been compacted. The adjacent individual webs 60 heat-sealed by pressure and embossed on both sides

1 sheet of drawings

'"**' ' 3154

Claims (3)

Patent claims: 1. A method for producing a thread fleece by spinning out a large number of continuous threads made of synthetic polymer and depositing the same on one. permeable movable base, characterized in that the threads leaving the spinnerets form thread bundles of 15 to 150 threads are combined and each thread bundle through an already proposed take-off nozzle in which the Propellant flow is brought to supersonic speed, stretched and digested in sub-bundles is that the thread bundles overlap when filing and that from substantially parallel single threads existing sub-bundles mutually arbitrarily oriented loops form. 2. The method according to claim 1, characterized in that on the deposited thread fleece is acted upon in a manner known per se with heat and pressure to a substantial part of the crossing sub-bundles at the crossing points of the threads. 3. Device for performing the method according to claim 1, characterized in that that at least five nozzle of the type already proposed ir a straight, perpendicular to Direction of movement of the pad aligned row are arranged.