Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D10/00—Physical treatment of artificial filaments or the like during manufacture, i.e. during a continuous production process before the filaments have been collected
  • D01D10/04—Supporting filaments or the like during their treatment
  • D01D10/049—Supporting filaments or the like during their treatment as staple fibres
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0061—Electro-spinning characterised by the electro-spinning apparatus
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/26—Formation of staple fibres

Definitions

• the invention relates to a process in which continuously from a spinning solution containing water, cellulose and tertiary amine oxide extruded spun threads, then stretched and passed through an air gap and a precipitation bath and finally cut into staple fibers.
• the invention also relates to a device for cutting lyocell filaments, having a precipitation bath stage which in use contains a precipitation bath containing a non-solvent for a lyocell spinning solution, and a continuously operable cutting means whereby the lyocell filaments can be cut into staple fibers in use are.
• the invention finally relates to lyocell staple fibers which are produced by the method and the device mentioned in the introduction.
• lyocell process The process for producing cut staple fibers or endless spin filaments from a spinning solution containing cellulose, water and a tertiary amine oxide such as N-methylmorpholine N-oxide is referred to as lyocell process.
• lyocell process The name
• a spinning solution containing water, cellulose and tertiary amine oxide is first promoted as a solvent at a temperature between 90 0 C and 120 0 C to a spinning head, where the spinning solution is extruded into an air gap through spinnerets to spun yarns.
• the filaments pass through the air gap and dip into a precipitating bath of non-solvent. In the precipitation bath, the cellulose is precipitated.
• WO-A-94/28220, WO-A-94/27902, WO-A-94/27903, WO-A-95/21520 and WO-A-02/31236 describe processes. in which the filaments are first washed after the precipitation bath in a water bath, then dried and then crimped before cutting. The washing step serves to remove the tertiary amine oxide from the filaments before cutting.
• WO-A-92/14871 is concerned with the washing of the filaments before cutting to remove the tertiary amine oxide from the filaments.
• the washing takes place in countercurrent baths, which are kept at a controlled pH.
• WO-A-01/86043 and EP-A-1 362 935 describe how nonwoven mats are made from lyocell fibers without cutting by centrifugal spinning or by directly forming a random web on a conveyor belt.
• the spun threads are also washed and crimped before being cut.
• they are post-stretched in a simultaneous heat treatment.
• the known methods and devices already lead to usable staple fibers.
• the mechanical strength values of the staple fibers produced by the known methods are too low.
• One for Staple fibers particularly relevant strength value here is the Schiingenfestmaschine, which gives evidence of a variety of fiber properties, such as the deformation behavior and brittleness.
• the Schiingenfestmaschine is determined by a standardized test method according to DIN 53 843 Part 2.
• the invention is therefore based on the object to improve the known lyocell process for the production of staple fibers to the effect that the Schiingenfestmaschine is increased.
• this object is achieved according to the invention for the method mentioned that the filaments contain tertiary amine oxide during cutting.
• this object is achieved according to the invention in that no washing stages are arranged between the precipitation bath stage and the cutting agent, through which the tertiary amine oxide on the cutting means is washed from the lyocell filaments.
• Lyocell staple fibers whose sheeting strength is at least 15 cN / tex, and even at least 20 cN / tex when cutting at a higher concentration of tertiary amine oxide in the filaments, result with this method and this device.
• the solution according to the invention is not simple since it is based on the surprising finding that the loop strength of the finished staple fiber increases if the spun threads still contain tertiary amine oxide at the time of the cutting.
• the invention thus goes exactly the opposite way as described in the above-mentioned publications WO-A-94/28220, WO-A-94/27902, WO-A-94/27903, WO-A-95/24520, WO A-02/31236, WO-A-00/18991 and WO-A-04/88010. Indeed, following the teachings of these references, the tertiary amine oxide must be completely washed out of the filaments prior to cutting. However, the shearing strengths achievable with these methods lie below the loop strengths, which can be achieved with the method according to the invention.
• the reason for the increase in the Schiingenfestmaschine in the inventive method and apparatus of the invention seems to be that the spinning threads are cut in a state in which they are still highly swollen by the aqueous amine oxide and that the filaments can shrink freely after cutting in fibrous form.
• the staple fibers according to the invention have due to their short length, the full shrinkage options at full strain relief.
• the staple fibers produced according to the invention are less sensitive to other textile processing steps such as spinning, dyeing, finishing, crosslinking, etc.
• the filaments can be brought into contact with treatment liquid in treatment stages, which does not substantially reduce the concentration of tertiary amine oxide in the filaments and, in particular, does not completely rinse the tertiary amine oxide from the filaments.
• treatment baths may be arranged with appropriate treatment liquids having a high content of tertiary amine oxide, such as N-methylmorpholine N-oxide in the treatment liquid.
• the concentration of tertiary amine oxide should not be lower than the concentration of tertiary amine oxide in the filaments.
• tertiary amine oxide can additionally be introduced into the finished spun filaments by high concentrations of tertiary amine oxide in the treatment liquid.
• the spun yarns In order to perform the cutting operation on spun yarns swollen by the aqueous amine oxide, the spun yarns should be cut within 10 to 180 seconds and 20 to 180 seconds, respectively, after the extrusion. If the extrusion process is longer than 180 seconds, then already partially crystalline structures are found on the surface of the spun yarns, which are subjected to high mechanical stress in the course of the shrinking process of the spun fibers, so that not so high loop strengths are achieved. Preferably, however, the cutting process takes place at most 80 seconds, more preferably at most 60 seconds after the extrusion process.
• the first treatment of the filaments takes place with a treatment liquid immediately before the cutting process.
• the filaments can be guided in a flow of treatment liquid for cutting.
• an injector device can be used, in which a spun yarn guide channel is arranged.
• the filament guide channel ends immediately before the cutting stage and is flowed through during operation of a directed to the cutting means treatment liquid flow. In this flow, the filaments are entrained and transported to the cutting means.
• spraying or spraying devices and baths can also be provided, with the aid of which the filaments are wetted by the treatment liquid.
• washing operations are carried out prior to cutting in which tertiary amine oxide can be washed out of the filaments with a washing liquid, they should, according to the present teaching, be for the first time immediately before or during the
• the filaments cut with a high NMMO content are subject to greater shrinkage after cutting than is the case with the washed and NMMO-free cut filaments. Therefore, in order to adjust the desired staple fiber length in the cutting process, the cutting length of the fibers should be set at least 12 to 15% above the desired length of the dried staple fiber.
• the NMMO content of the treatment liquid in the treatment stages can be controlled automatically in an advantageous embodiment, wherein the NMMO content detected by sensors and deviations from a target value by automatic, metered additions of NMMO or a diluent such as water are compensated in the treatment liquid ,
• the device mentioned above may be provided with metering pumps and an electronic control unit signal-transmitting connected to the sensors and the metering pumps.
• the NMMO content may also be determined by hand and adjusted accordingly by manual addition of NMMO or a diluent.
• FIG. 1 shows a schematic view of a first exemplary embodiment together with an alternative embodiment
• Figure 2 is a schematic view of a second embodiment
• FIG. 3 shows a schematic representation of the influence of the NMMO concentration in the treatment fluid for the spun filaments on the sling strength of the staple fibers.
• the filaments 2 dip into the precipitation bath 3a of the precipitation bath stage 3.
• the precipitation bath 3 contains a non-solvent for the extruded filaments 2, so that the cellulose is precipitated in the filaments.
• the individual spun yarns from the spinnerets are collected on a roll-shaped deflection device 5 arranged in the precipitation bath 3a and forwarded as a fiber cable 6 consisting of a multiplicity of spun yarns to several or a pair of draw-off rolls 7.
• a pair of take-off rolls 7 and pairs of take-off rolls 7 can be arranged one behind the other.
• the fiber cable 6 is led to a cutting stage 8 '.
• a treatment stage 8 " by means of which the spun threads 2 are impregnated with an amine oxide-containing treatment liquid immediately or shortly before the cutting process.
• the spinning surfaces are continuously passed to cutting means 9, which cut the filaments into staple fibers.
• the cutting means 9 are located at a position which is reached by the spun yarns 2 within at most 180 s, but preferably at most 80 s, and ideally within at most 60 s after the extrusion.
• the injector 8 has a spun yarn guide channel 10, which in operation flows through a treatment liquid in the direction of the cutting means 9 and thereby transports the filaments 6 combined in the fiber cable 6 to the cutting means 9.
• the injector 8 thus simultaneously forms a conveying means and a treatment stage for the filaments.
• the treatment stage is structurally integrated with the cutting means 9 in this embodiment to form a structural unit.
• the cutting means 9 are, for example, rotating cutting knives, which are mounted on a rotating cutting disc 11 and are pressed by a spring mechanism 12 against a slip ring 13, which keeps the knives sharp during operation.
• the drive of the cutting means 9 is a motor 14th
• the exit of the filament guide channel 10 is arranged so that it is swept by the rotating circle of the cutting means 9 and the combined in the fiber cable 6 filaments 2 are cut every time a cutting means 9 passes over the outlet of the injector 8.
• the staple fibers 15 obtained in this way are rinsed out after the cutting process together with the treatment liquid.
• the staple fibers 15 can be randomly dropped onto a conveyor 16, from which they are transported to further processing steps.
• the treatment liquid from the injector is collected in a collecting container 17 and can, as indicated by the arrow 18, a cleaning, such as a filtration, are supplied. After cleaning, the regenerated treatment liquid according to arrow 19 can be fed back under pressure of the treatment stage.
• a control unit 20 measures via a sensor 21 the content of tertiary amine oxide, in particular of N-methylmorpholine N-oxide, in the treatment liquid 22. Softens the concentration of tertiary amine oxide in the treatment liquid 22 from a predetermined target value for the concentration, for example, a target value of 4 percent by mass NMMO, so this deviation can be corrected via the control device 20.
• a non-solvent such as water
• the control unit 20 via data lines 25, which may also be implemented wirelessly, connected to these devices signal transmitting.
• the spun threads can also be used with highly swelling liquids which are miscible with the tertiary amine oxide.
• hydrophilic polymers such as polyethylene glycol or polyethylene glycol derivatives having different molecular weights of, for example, 200, 400 or 1000 in diluted form and in concentrations of 0.2 g / l and 1 g / l of the treatment liquid in the cutting stage.
• the concentration of the tertiary amine oxide in the treatment liquid recirculated to the injector is at least 2 to 4% by mass, preferably at least 10 to 12% by mass.
• the treatment liquid comes into contact with the spun yarns immediately before cutting, the treatment liquid can also be used for washing the spun yarns. Because of the short exposure time of the washing liquid and the integration of this first washing stage in the cutting machine namely the tertiary amine oxide can not completely washed out. The cutting process still takes place in this case under sufficient NMMO concentration in the filaments 2.
• treatment stages in the form of treatment baths 26 through which the spun yarns 2 of the fiber cable 6 are routed can be arranged between the precipitation bath stage 3 and the treatment liquid stage adjoining the cutting means 9. These treatment stages may be provided instead of or together with the treatment stage integrated in the cutting machine.
• FIG. 1 by way of example only a single optional treatment bath 26 is shown. However, it is also possible to provide several treatment baths in succession.
• Essential for the nature of the treatment liquid in the treatment bath 26 is that the tertiary amine oxide is not washed out of the fiber cable 6, so that at the cutting means 9, the spun yarns 2 still have a sufficiently high content of tertiary amine oxide.
• the treatment bath 26 or any further treatment baths 25 between the precipitation bath 3 and the cutting means 9 likewise has a concentration of at least 2 to 4% by mass, preferably of at least 10 to 12% by mass of tertiary amine oxide.
• NMMO-containing cut staple fibers shrink more after being cut than the staple fibers in which the tertiary amine oxide was selected prior to cutting, a cut length 12 to 15% longer than the length of the finished staple fiber must be set on the cutters 9 lies.
• the cutting means 9 is configured differently.
• the cutting means 9 has a plurality of cutting blades 30, which are arranged between two axially spaced, rotating disks 31, 32 and are directed radially outward, so that the cutting surface of the cutting blades 30 faces outward in the radial direction.
• the fiber cable 6 extends between the pressure roller 33 and the cutting means 9 and is pressed by the pressure roller 33 in the cutting blade 30 and cut into staple fibers 15, which are transported via a conveyor 16 to further processing steps.
• the length of the staple fibers 15 load over the distance 34 of the cutting blade 30 from each other in the circumferential direction.
• the fiber cable is wetted with a treatment liquid 35 which is directed by spraying or spraying means 36 onto the area of the fiber cable 6 immediately before the cutting means 9.
• the treatment liquid 35 preferably has a concentration of tertiary Amine oxide, which corresponds to the concentration of the tertiary amine oxide in the filaments at this point.
• the treatment liquid 35 also in radial through the gaps between see the cutting blades 30, so between the two cutting discs 31, 32 follow in the radial direction, so that the blades are simultaneously flushed by deposits of the treatment fluid and in particular the treatment fluid directly to the Cutting point is passed.
• the NMMO concentration was adjusted to different values in 8 test runs, the NMMO concentration being kept constant at these values. Finally, the Schiingenfestmaschine the staple fibers thus obtained with the Schiingenzuggrass according to DIN 53 843 Part 2 was measured.
• FIG. 3 shows in a diagrammatic representation the values of the above table.
• the loop strength increases only slower with the increase in the NMMO concentration than in the first region A, however, the achievable values for the loop strength are greater overall and are close to the limit c BC of around 20 cN / tex.
• the second limit value c BC is between 10% by mass and 12% by mass.
• the Schiingenfestmaschine changes only to a small extent.
• the achievable values for the Schiingenfestmaschine in the range C are at least 20 cN / tex, as the above experimental examples show, even at around 21 cN / tex.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Treatment Of Fiber Materials (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2005
  • 2005-05-24 DE DE200510024433 patent/DE102005024433A1/de not_active Ceased
• 2006
  • 2006-03-06 CN CN2006800261984A patent/CN101287864B/zh active Active
  • 2006-03-06 WO PCT/EP2006/002026 patent/WO2006125484A1/de not_active Application Discontinuation
  • 2006-03-06 BR BRPI0613269A patent/BRPI0613269B1/pt active IP Right Grant
  • 2006-03-06 TR TR2007/08112T patent/TR200708112T2/xx unknown
  • 2006-03-06 EP EP06723229A patent/EP1883721A1/de not_active Withdrawn
  • 2006-03-06 KR KR1020077029639A patent/KR100957802B1/ko active IP Right Grant
  • 2006-05-12 TW TW95116969A patent/TWI329683B/zh active
• 2007
  • 2007-11-26 ZA ZA200710165A patent/ZA200710165B/xx unknown

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