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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/18—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide
• • 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
  • D01D5/04—Dry spinning methods

Definitions

• the invention relates to a continuous process for the production of crimped threads and fibers from acrylonitrile polymers with at least 40% by weight of acrylonitrile units.
• a “continuous process” is understood to mean that the threads are spun, stretched, crimped, shrunk, fixed and optionally cut into staple fibers in one operation without interruption using the dry spinning method.
• Acrylic fibers are usually produced using wet spinning, dry spinning and melt spinning technologies. While continuous processes have already become known in the production of acrylic fibers using the wet spinning and melt spinning technique, for example the wet spinning process according to Textile Technology 26 (1976), pages 479-483 or the melt extrusion process according to DE-A 2 627 457 which have no restriction whatsoever with regard to Ribbon weights are subjected to hitherto, only a continuous process for the production of acrylic fibers after the dry spinning process has become known, which is only applicable to multifilament yarns with low ribbon weights, so-called acrylic silk, and under which certain conditions must be met (US-A2811 409) not suitable for the production of acrylic cables with high tape weights
• the wet spinning process in which the spinning solution is spun into a precipitation bath, where it coagulates to form threads which are washed, drawn, dried and prepared without interrupting the process, nozzles with a large number of holes of approximately 10,000 are used.
• the spinning speed is relatively low at 5 to 20 m / min.
• the dry spinning process is therefore interrupted before drawing, the spinning material is collected in cans, from which it is then fed to further post-treatment (Bela von Falkai, Synthesefaser, Verlag Chemie, Weinheim / Deerfield Beach, Florida / Basel (1981), p. 204-206; R. Wiedermann, acrylic fiber spinning and after-treatment processes in man-made fibers / textile industry, June 1981, pp. 481-484, in particular p. 482 left column above).
• a batch process is e.g. B. from DE-A 1494 553, in which work is carried out with take-off speeds of over 300 m / min and a stretching factor of 1: 4.5.
• the threads After leaving the spinning shaft, the threads are provided with an aqueous, antistatic preparation. After the process has been interrupted, the threads are drawn, washed and finished in the usual way.
• the object of the present invention to provide a continuous process for the production of acrylic fibers by the dry spinning method, in which all process stages of the thread formation to the ready-to-ship fiber take place in one work process without any interruption or intermediate storage, and which can be applied to spinning cables with high strip weights.
• the preparation of the spinning solution should be able to be integrated into the continuous process.
• the spinning delay of the process is greater than 2, in particular it is between 2 and 12.
• the spinning solution at 100 ° C. has a viscosity of 15 to 50 falling ball seconds (6.56 to 21.85 Pa.s)
• the solvent content of the threads when leaving the spinning shaft is max. 20% by weight, in particular max. 10% by weight, based on the fiber solids content and the strip temperature, is 100 to 180 ° C. during stretching.
• the stretching ratios are in particular between 2 and 12, the preferred range for copolymers 3 to 6 and for homopolymers 5 to 12.
• the method according to the invention it is possible to produce spinning tow with a ribbon weight of 100,000 dtex and more with such a low content of residual solvent that after hot stretching and a subsequent crimping and shrinking process, the residual solvent content in the finished fiber or in the continuous cable is clearly below 1% by weight lies without the spinning material coming into contact with an extracting agent for the spinning solvent, apart from the water content of the spinning preparation.
• the threads obtained according to the invention have fiber strengths of over 2 cN / dtex.
• Suitable acrylonitrile polymers are all acrylonitrile homopolymers and copolymers which can be spun into so-called acrylic fibers or modacrylic fibers, preferably acrylonitrile copolymers with at least 85% by weight of acrylonitrile units. Homopolymers and terpolymers made from 89 to 95% by weight of acrylic, 4 to 10% by weight of a non-ionic comonomer and 0.5 to 3% by weight of an ionogenic comonomer are particularly preferred, the comonomers being methyl acrylate and methyl methacrylate and vinyl acetate and, on the other hand, methallyl sulfonate and styrene sulfonate are preferred. The polymers are known.
• the process according to the invention differs from the process of US Pat. No. 2,811,409 in that the spinning solution has a different viscosity, which should not be less than 400 poise at 100 ° C., corresponding to 91 ball falling seconds at 100 ° C., individual examples also being 300 poise go down corresponding to 69 falling ball seconds, and due to the delay, which is mostly between 0.5 and 1.5. Examples with higher delays have extremely high viscosities. As mentioned, the process is limited to very low strip weights and requires a complicated spinning shaft.
• the method according to the invention is preferably carried out with a spinning shaft, in which the hot air used to evaporate the spinning solvent is blown in at the head of the spinning shaft, at most 50 cm below the spinneret, in the longitudinal and / or transverse direction to the threads.
• the spinning material d. H. the spinning cable leaving the spinning shaft has a residual solvent content of less than 40% by weight, in particular between 2 and 10% by weight, based on the dry weight of the fiber, because spun material with residual solvent contents of more than 40% by weight, for example of dimethylformamide, sticks together during the subsequent hot stretching via godets at strip temperatures from around 120 ° C. If, to avoid this, one stays at strip temperatures below 100 ° C, then an undesirable cold expansion of the material takes place, i. H. an uneven and imperfect stretching under not exactly defined conditions, the stretching degree being limited to a maximum of 3: 1.
• the spun material with residual solvent contents below 40% by weight can be stretched over godets or into a steaming zone without sticking and tearing at belt temperatures of up to 180 ° C, it being necessary for the spinning material to be in a hot state before stretching, preferably at the end of the Wet the spin shaft, either inside or immediately behind the spin shaft, with a preparation that contains a lubricant and an antistatic, and hot stretch it directly without cooling.
• the lubricant allows perfect stretching of even thick cables of 100,000 dtex and more.
• the preparation can also contain water as an ingredient, but care must be taken that the cable does not absorb more than 10% by weight of moisture. If the cable contains large amounts of water, it cools down strongly and unevenly, and during the subsequent hot stretching, no faulty stretching is achieved despite the high stretching temperatures of 200 ° C. and more.
• the cable shows tears or windings on the godets.
• Suitable lubricants are glycols, their derivatives, silicone oils, ethoxylated fatty acids, alcohols, esters, amides, alkyl ether sulfates, and mixtures thereof.
• the preparation can contain a corresponding commercially available preparation, for example a customary cation-active, anion-active or nonionic compound, such as a long-chain ethoxylated, sulfated and neutralized alcohol.
• the preparation expediently has a temperature of 50-90 ° C. in order to prevent the hot thread sheet from cooling.
• the manhole tapes spun by a spinning machine with, for example, 20 spinning chutes and having a total titer of 100,000 dtex or more are prepared in this way, bundled and fed via a take-off device to a pair of rollers which can be heated inductively to over 200.degree.
• a clamping point is produced by looping the pair of rollers one or more times, if necessary by means of an additional roller.
• a coolable withdrawal quintet or septet serves as the second clamping point, which is arranged at a distance of approx. 3 m from the inductively heated pair of rollers and causes the cable to be stretched by a correspondingly higher speed.
• the cooling of the rollers on the second stretching element is necessary in order to avoid caking and rigidity in the subsequent crimping process, which are observed in the case of acrylic fibers at temperatures above approximately 130 ° C.-140 ° C.
• the spinning solvent residues escaping during hot drawing are suctioned off and recovered via a cooling system.
• Septet rollers which are heatable at the beginning and coolable at the end have proven to be preferred stretching members.
• a tube heated with superheated steam or hot air can advantageously be integrated between the septet rollers.
• spinning take-off speeds of 50-100 m / min are completely sufficient to keep the residual solvent content in the spun material clearly below 10% by weight, so that at speeds of 300-1000%, final speeds of 150 to 1000 m / min are achieved are technically manageable.
• the cable is then crimped in a stuffer box or fed at speeds above 300-400 m / min to a high-performance texturing nozzle, in which crimping is preferably carried out with the aid of superheated steam of at least 105 ° C.
• the crimped cable is relaxed with saturated steam, superheated steam or even in dry heat for shrinkage removal, for example over a wire belt or U-tubular steaming boots.
• the shrunk cable is then packaged or cut into staple fibers and pressed into bales as required.
• the process is particularly suitable for the production of spun-dyed threads and fibers by adding soluble dyes, in particular cationic dyes or pigments, to the spinning solution, because when the color is changed due to the special work-up, considerably less rejects are obtained.
• Solution preparation can also be easily integrated into the continuous process; using conventional solution preparations or in particular the following method:
• a suspension is first prepared at room temperature from the spinning solvent, the polymer and optionally a non-solvent for the polymer which is miscible with the spinning solvent, for example water in an amount of 2 to 20 g per 100 g of polymer.
• This suspension is heated to a temperature which is at least 30 and at most 60 ° C above the temperatures at which the Sus pension is optically homogeneous, i.e. a solution is formed, held at this temperature for 1 to 15 minutes and then immediately fed to the spinning.
• the method according to the invention is also suitable for the continuous production of bicomponent threads and fibers, in which the post-treatment steps are modified accordingly in accordance with the known technology for bicomponent threads.
• dimethylformamide (DMF) are mixed in a kettle at room temperature with stirring, with 300 kg of an acrylonitrile copolymer made from 93.6% acrylonitrile, 5.7% methyl acrylate and 0.7% sodium methallylsulfonate with a K value of 81.
• the suspension is pumped via a gear pump into a spinning kettle equipped with an agitator. Then the suspension is heated in a double-walled tube with steam of 4.0 bar. The dwell time in the tube is 5 minutes.
• the spinning solution which has a temperature of 138 ° C at the tube outlet and a viscosity of 19 falling ball seconds (8.30 Pa.s), measured at 100 0 C, is filtered, cooled to 90 ° C after leaving the heating device and filtered directly to a spinning plant fed with 20 spinning shafts.
• the spinning solution is dry spun from 1264 perforated nozzles, nozzle hole diameter 0.2 mm, with a take-off speed of 50 m / min and a spin delay of 7.2.
• the dwell time of the spinning threads in the spinning shafts is 5 seconds.
• the shaft temperature is 200 ° C and the air temperature is 350 ° C.
• the throughput of air is 40 m 3 / h for each shaft, which is blown in at the head of the shaft in the longitudinal directions to the threads.
• the spinning material with a total titre of 310,000 dtex, which still has a residual solvent content of 11.1% by weight, based on the solids content, is wetted with an 80-90 ° C warm, aqueous, oil-containing, antistatic preparation in this way immediately after leaving the spinning shafts that the oil content of the threads is 0.16% by weight, the antistatic content is 0.04% by weight and the moisture is 1.1% by weight, based on the fiber solids content.
• the preparation is dosed via gear pumps.
• the warm cable is then sent over a pair of rollers heated inductively to 20 ° C., with a contact time of approx. 2 seconds being achieved by looping several times over a feed roller.
• the cable assumes a strip temperature of 156 ° C, measured with the KT 15 radiation thermometer.
• the cable is stretched by 500%, with a stretch septet with coolable rollers serving as the second clamping point.
• the strip temperature after the stretching process is 80 ° C.
• the cable is crimped in a stuffer box and relaxed in a tube which is fed with saturated steam.
• the dwell time in the steam pipe is approx. 4 minutes.
• the fully shrunk cable is then cut into staple fibers with a cutting length of 60 mm, blown and fed to a packing press.
• the acrylic fibers produced in this way in a continuous process have a single fiber final titer of 3.3 dtex.
• the fiber strength is 3.4 cN / dtex and the elongation is 48%.
• the fibers are completely vacuole-free, have a density of 1.181 g / cm 3 and a completely smooth, structureless fiber surface.
• Yarns made from the fibers on a high-performance card at 140 m / min have a yarn strength of 17.5 RKm, an elongation of 19.4% and a yarn boiling shrinkage of 2.2%.
• the following table 1 shows the running method for different degrees of stretching and strip temperatures for spinning material of the same total titer 310 00 dtex with different DMF contents.
• the various DMF contents in the spinning material were produced by varying the shaft, air temperature, air volume and the residence time in the spinning shaft.
• the table for residual solvent contents in the spun material above approx. 40% by weight, it is no longer possible to achieve reasonable modes of operation with sufficient fiber strengths.
• the spun material cakes or is only stretched cold.
• a spinning solution according to Example 1 is dry spun from 380 perforated nozzles, nozzle hole diameter 0.2 mm, with a take-off speed of 166.6 m / min and a spin delay of 5.7.
• the dwell time of the spinning threads in the spinning shafts is 1.5 seconds.
• the shaft temperature is 160 ° C and the air temperature is 300 ° C, the throughput of air is 40 m 3 / h for each shaft.
• the viscosity of the spinning solution is again 19 ball falling seconds (8.30 Pa. S), measured at 100 ° C.
• the oil content of the threads is 0.18% by weight
• the antistatic content is 0.04% by weight
• the moisture content is 1.9% by weight, based on the solids content.
• the warm cable is again warmed, as described in Example 1, stretched 3.6 times with a belt temperature of 133 ° C, cooled via septet rollers and crimped with a belt temperature of 66 ° C and relaxed in a tube with saturated steam.
• the shrunk cable is then cut into staple fibers with a cutting length of 60 mm, blown and fed to a packing press.
• the acrylic fibers produced in this way by a continuous process have a single fiber denier of 5.0 dtex.
• the strength is 2.1 cN / dtex and the elongation is 39%.
• the density is 1.182 g / cm 3 .
• the fiber surface is completely smooth and streak-free.
• Yarns made from the fibers on the high-performance card at 130 m / min have a yarn strength of 12.2 RKm, an elongation of 19.4% and a yarn boil shrinkage of 3.0%.
• a spinning solution according to Example 1 is dry spun from 1264 hole nozzles, hole diameter 0.2 mm, with a take-off speed of 125 m / min and a spinning delay of 6.3.
• the dwell time of the Spinning threads in the spinning shafts is 2 seconds.
• the shaft temperature is 200 ° C and the air temperature is 350 ° C.
• the throughput of air is 40 m 3 / h for each shaft.
• the viscosity of the spinning solution is again 19 ball falling seconds (8.30 Pa.s), measured at 100 ° C.
• the spinning material with a total titre of 356,000 dtex, which still has a residual solvent content of 24.1% by weight of DMF, is treated at the end of the spinning shaft with an 80-90 ° C.
• the warm cable is heated up to a strip temperature of 145 ° C via septet rollers and subjected to superheated steam of 122 ° C in a 5 m long tube.
• the cable is stretched in the steam pipe by 900%, with a stretch septet with coolable rollers serving as the second clamping point.
• the cable is crimped by a blow nozzle with superheated steam of 140 ° C and relaxed on a screen belt with hot air at 190 0 C.
• the residence time is 2.5 minutes.
• the escaping residual solvent vapors are recovered via an extraction system and a cooling system.
• the shrunk cable is then cut into staple fibers with a cutting length of 60 mm and fed to a pack press.
• the acrylic fibers thus produced in a continuous process have a single fiber final titre of 1.9 dtex.
• the fiber strength is 4.7 cN / dtex and the elongation is 13%.
• the fibers are completely vacuole-free and have a density of 1.181 g / cm 3 .
• Yarns made from the fibers on a high-performance card at 140 m / min have a yarn strength of 22.7 RKm, an elongation of 17.5% and a yarn boiling shrinkage of 2.3%.
• Example 755 kg of dimethylformamide (DMF) were mixed in a kettle at room temperature with stirring, with 245 kg of an acrylonitrile homopolymer having a K value of 91.
• the suspension is dissolved, filtered and fed directly to a spinning plant with 20 spinning chutes.
• the viscosity of the spinning solution measured at 100 ° C, is 38 falling ball seconds (16.6 Pa.s).
• the spinning solution is dry spun from 380 perforated nozzles, nozzle hole diameter 0.2 mm, with a take-off speed of 41.6 m / min and a spin delay of 4.8.
• the dwell time of the spinning threads in the spinning shafts is 6 seconds.
• the shaft and air temperatures correspond to the information in Example 1.
• the air volume is 45 m 3 / h.
• the acrylic fibers produced in this way in a continuous process have a final fiber titer of 1.6 dtex, a fiber strength of 5.2 cN / dtex and an elongation of 11%.
• the fibers are completely vacuole-free and have a density of 1.184g / cm 3 .
• Yarns made from the fibers on the high-performance card at 120 m / min have a yarn strength of 24.7 RKm, a yarn elongation of 14.6% and a yarn boiling shrinkage of 3.4%.
• a spinning solution according to Example 1 is dry spun from 1264 perforated nozzles, nozzle hole diameter 0.2 mm, with a take-off speed of 208.3 m / min and a spin delay of 7.2.
• the dwell time of the spinning threads in the spinning shafts is 1.2 seconds.
• the shaft temperature is 160 ° C and the air temperature is 260 ° C.
• the air volume is 35 m 3 / h for each shaft.
• the warm cable, as described in Example 1 is sent over a pair of rollers heated inductively to 200 ° C. and, as indicated there, stretched 1: 5 times.
• the belt temperature is 179 ° C.
• the cable is glued and there are constant runs and tears in the plug-in area on the rollers and the idler roller.
• a further increase in temperature up to 240 ° C, with a measured strip temperature of 204 ° c, as well as a reduction in the degree of insertion does not improve the running behavior.
• the fibers have a single fiber final titer of 4.5 dtex and a fiber strength of only 1.3 cN / dtex at an elongation of 123%.
• a cold expansion of the cable containing a lot of residual solvent If the stretching is carried out over septet rolls with an intermediate steam tube under the conditions as described in Example 3, the same results are obtained.
• a spinning solution according to Example 1 is, as described there, dry spun from 1264 perforated nozzles.
• Example 6 Another part of the spun material from Example 6 is again drawn by 500% at a roll temperature of 240 ° C.
• the strip temperature is 139 ° C.
• the cable is then crimped directly in a stuffer box without cooling and, as described in Example 1, relaxed.
• the cable is baked streaky and has a water rigidity. After cutting, there are large amounts of undissolved cut bandages.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (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)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6167766

Family Applications (1)

Country Status (4)

Families Citing this family (17)

Family Cites Families (11)

• 1982
  • 1982-07-06 DE DE19823225266 patent/DE3225266A1/de active Granted
• 1983
  • 1983-06-17 US US06/505,544 patent/US4457884A/en not_active Expired - Fee Related
  • 1983-06-24 DE DE8383106170T patent/DE3361408D1/de not_active Expired
  • 1983-06-24 EP EP83106170A patent/EP0098477B2/de not_active Expired - Lifetime
  • 1983-07-05 JP JP58121118A patent/JPS5921711A/ja active Granted

Also Published As

Similar Documents

Legal Events