Discontinous polyethylene terephthalate fibres and method for producing the same
AssigneeLurgi Zimmer GmbH
InventorsIngo Cordes, Christian Kellner, Ulrich Mirwaldt, Dietmar Wandel
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Abstract
PTT staple fibers which are characterised by a novel combination of properties. In combination with novel stress-strain properties and modulus parameters, staple fibers or textiles or home textiles having extremely desirable aesthetics and service quality are obtained. Economical two-stage process for the production of PTT staple fibers. The melt spinning is carried out at a high polymer throughput and a spinning take-off speed of at least 600 m/min. In a separate fiber drawing frame, the stretching, heat-setting, crimping and drying are carried out.
Claims8
PTT staple fibres, having an intrinsic viscosity in the range 0.70-1.3 dl/g, an LASE (10%) of from 5 to 12 cN/tex, a secant modulus (Rd−45%) of <1.0 cN/tex per 1% and a crimp stability of >75%, said PTT staple fibres being dyeable with dispersion dyes without addition of carrier/dye absorption aids.
Process for the production of PTT staple fibres having an intrinsic viscosity of at least 0.70 dl/g by a two-stage spinning and stretching process, wherein
- a) a PTT melt at a temperature TS (° C.)=TM+k, where TM is the melting point of the PTT and 7£k£63, is fed through a product line heated at a temperature T1 in the range from 234 to 290° C. by means of an external heat transfer medium to a spinning beam heated at TB234 to 290° C. having, in the flow direction, at least one spinning pump, spin pack and spinneret plate having a hole density of from 0.3 to 20 holes/cm2, and is spun through the at least one spinneret plate to give melt strands, with the mean residence time of the PTT melt being less than 30 minutes in the product line and a maximum of 4 minutes in the spin pack, and the spinning draft being from 1:30 to 1:160, and the flow rate F in g/min per spinneret hole, based on the fibre titre in dtex, being in the range from 0.14 to 0.66,
- b) the melt strands are cooled by means of turbulence-free cooling air at from 5 to 25° C. flowing in perpendicularly to the strand running direction at a mean air exit speed of from 0.5 to 2.0 m/sec and a blow zone length of from 50 to 2000 mm, and the cooled strands are treated with a water/oil mixture in such a way that from 12 to 30% by weight of water remain on the strands, and the strands are gathered together to form filament bundles, which are themselves combined to form spun tows, which are taken off at a take-off speed in the range from 600 to 2000 m/min and deposited in cans,
- c) the spun tows are taken off from the cans via a feed unit and comb and fed to a fibre drawing frame, in which they are stretched in at least one stretching stage at from 20 to 100° C., optionally heat-set at a maximum of 210° C. and relaxed, where the production speed is from 25 to 400 m/min, subsequently cooled to below the glass transition temperature and, after being combined to form at least one tow, crimped in one stuffer box crimping machine per tow, the tows are optionally post-treated with an oil/water mixture and then dried at from 30 to 200° C. over the course of from 0.5 to 10 minutes and finally cut to give staple fibres in a directly subsequent or separate operation.
Dependencies are inferred from the claim text.