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
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/90—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyamides
• • 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
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • 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
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/92—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyesters

Definitions

• This invention relates to the manufacture of synthetic fibres by melt spinning and drawing a high molecular weight, high viscosity, fibre-forming polymer, more particularly polyethylene terephthalate or nylon 66, containing another polymer which is immiscible in a melt of the fibre-forming polymer.
• Japanese Patent No 56-118912 (Teijin KK) is concerned with the manufacture of a high strength fibre by melt spinning polyethylene terephthalate containing between 1 and 7 parts by weight % of a bisphenol type polycarbonate.
• the melt spun fibre is wound up at a speed of 1500 m/minute or less.
• the limiting viscosity of the polyethylene terephthalate used must fall between 0.55 and 0.70. If it falls below 0.55, satisfactory strength and modulus cannot be developed in the fibre. On the other hand, when the limiting viscosity is in excess of 0.70, recognisable improvement in strength becomes insignificant or disappears and there is a tendency for the modulus value to decline as well.
• the present invention therefore, we provide a process of melt spinning a fibre-forming polymer having a high viscosity, more particularly high viscosity polyethylene terephthalate or nylon, in which before melt spinning, there is added to the fibre-forming polymer between 0.1% and 10% by weight of another polymer which is immscible in a melt of the fibre-forming polymer and which has an average particle size less than 3 microns in the melt immediately prior to spinning.
• the additive polymer has an average particle size in the melt of substantially less than 3 microns and more preferably of the order of 1 micron.
• high viscosity is used, in relation to polyethylene terephthalate, to mean that it has an intrinsic viscosity greater than 0.70 and, in relation to nylon 66, to mean that it has a relative viscosity greater than 45 and more preferably greater than 55.
• the intrinsic viscosity of polyethylene terephthalate is measured in ortho-chloro-phenol.
• the relative viscosity of nylon 66 is measured on a 8.4% w/w solution in 90% formic acid compared with the viscosity of 90% formic acid itself.
• an “imiscible polymer” we mean that at the spinning temperature such a polymer forms a two phase melt with the fibre-forming thermoplastic polymer. Microscopic examination and optical photographs of such a melt show a two phase system in which the immiscible polymer is in the form of circles (indicating spherical particles) dispersed in the continuous, fibre-forming, polymer matrix.
• an immiscible polymer to exclude a liquid crystal polymer, ie the additive polymers used in the invention do not form an anisotropic melt in the temperature range at which the thermoplastic polymer may be melt spun. This anisotropic condition may form when a liquid crystal polymer is heated or by the application of shear to the polymer, although in the latter case it must persist for a few seconds.
• a process of melt spinning a fibre-forming polymer more particularly either polyethylene terephthalate having an intrinsic viscosity greater than 0.70 or nylon having a relative viscosity greater than 45 and more preferably greater than 55, in which before melt spinning, there is added to the fibre-forming polymer between 0.1% and 10% by weight of another polymer which is immiscible in a melt of the fibre-forming polymer and which has an average particle size less than 3 microns in the melt immediately prior to spinning and taking up the spun fibre at a wind up speed less than 1 kilometre/minute.
• a process of melt spinning a fibre-forming polymer more particularly either polyethylene terephthalate having an intrinsic viscosity greater than 0.70 or nylon having a relative viscosity greater than 45 and more preferably greater than 55, in which before melt spinning, there is added to the fibre-forming polymer between 0.1% and 10% by weight of another polymer which is immiscible in a melt of the fibre-forming polymer and which has an average particle size less than 3 microns in the melt immediately prior to spinning and taking up the spun fibre at a minimum wind up speed of 1 kilometre/minute.
• nylon 66 any suitable immiscible polymers for example polyolefines, such as polyethylene and polypropylene, polyesters, such as polyethylene terephthalate, and polyethylene glycol, may be used.
• any suitable immiscible polymers may be used for example polyolefines, such as polyethylene and polypropylene, and polyethylene glycol.
• a preferred immiscible polymer is nylon 66.
• the extensional viscosity of nylon 66 is such that the molten spheres of the polymer immediately prior to spinning, deform into microfibrils along the spinning threadline.
• melt spun fibres of polyethylene terephthalate made from polymer having an intrinsic viscosity greater than 0.70 containing between 0.1% and 10bl by weight of nylon 66 which is present in the melt spun fibres as microfibrils.
• These microfibrils have an aspect ratio ie length/diameter ratio which is very high eg typically greater than 50 and such microfibrils will have diameters of about 0.5 micron. It is believed that it is the conversion of the spheres of nylon 66 into microfibrils and the extent of this deformation that produces the change of rheology which is responsible for the orientation suppression and in turn wind up speed suppression which is referred to below.
• a major advantage of the process of the invention is that it allows significant productivity gains to be achieved.
• the effect of blending the immiscible polymer with the fibre-forming polymer is that of orientation suppression which manifests itself as wind up speed suppression ie the properties of the spun fibre are those that would be obtained from fibre which has been spun at a lower wind up speed.
• the properties of the drawn yarn decrease. Accordingly by lowering the effective wind up speed by the addition of an immscible polymer (while keeping the actual wind up speed the same) it is possible to achieve improved properties such as a higher modulus which is quite surprising in view of the teaching of Japanese Patent No 56-118912.
• a particularly useful property of a sewing thread is its modulus, since it has been found that a higher modulus allows faster sewing speeds and gives less puckering of sewn seams.
• a higher modulus can, of course, be obtained in the normal drawing process by using a higher draw ratio but this is not very desirable since it can lead to a high break level.
• the present invention achieves this object in a much more convenient and efficient manner.
• Polyethylene terephthalate having an intrinsic viscosity (IV) (measured in ortho-chloro-phenol) of 0.73 was dried at 165 0 C for 4 hours and blended with 3% by weight of Imperial Chemical Industries PLC.
• the barrel temperature was 290°C and the screw was rotated at 50 rpm.
• a lace of 0.1 inch diameter was extruded into a water bath and then passed to a lace cutter. The average output rate was 100 grams per minute.
• polyethylene terephthalate alone was extruded in a similar manner.
• the chips from the lace cutter were then dried at 165°C for 4 hours and made into candles at 240°C for 8 mins.
• the candles were then spun on a rod spinner.
• the spinning temperature was 293°C and the throughput per hole was 96 gm/hr/hole into ambient air with no deliberate quenching apparatus, using 35 thou spinneret holes.
• the filaments so formed were wound up at a wind up speed (WUS) of 200 mpm to 1000 mpm without adjustment of spinning rate so that higher speeds yielded finer filaments.
• the intrinsic viscosity of the control fibre after spinning was 0.70.
• the wind up speed suppression produced a potential increase in productivity that can be calculated from the extensibility of the spun filaments as determined on an Instron.
• the gauge length used was 10 cms and the strain rate was 200% per minute.
• a spun filament has a percent extension-to-break of E, then the maximum draw ratio to which it can subsequently be subjected is roughly (1 + E/100). If a second spun filament has a larger extension-to-break E' then it can be subjected to a larger draw ratio, roughly (1 + E'/100). To nake drawn filaments of equal decitex d at these maximum draw ratios the spun filaments mist therefore have decitexes of d(1 + E/100) and d(1 + E'/100) respectively. If both filaments are spun at the same speed their production rates are proportional to these decitexes and the percentage increase in productivity of the second filament is
• Example 2 gives results for other concentrations of nylon and demonstrates that even very small amounts of nylon are very effective in producing orientation suppression.
• the same blending and spinning conditions were used as in Example 1 except that the spinneret hole used was 15 thou.
• This example demonstrates that better tensile properties are obtained at the same WUS by the use of a nylon blend.
• the improvement shown is in the initial modulus after drawing.
• the . polymers were blended and spun as in Example 1 at 96g/hr/hole and 800 mpm. They were then drawn to a range of final extensions, using a hot pin at 85°C, a hot plate at 170°C and a draw speed of 20 mpm.
• a special technique was used on the Instron to measure the initial modulus very precisely. The gauge length was 50 cm, the cross head speed was 5 cm per minute and the chart speed was 100 cm per minute. This gave a load-strain curve which was linear up to 2% strain and from which the initial modulus could be very accurately measured. For a given final extension there was a small scatter of a few percent, and all the results obtained are given in Table 3.
• the modulus of the 1% and 3% nylon blends is about 20% higher then the control at 10% drawn extension.
• the draw ratio of the control for 10% extension was 3.9, while that of the 1% blend was 4.9, giving a productivity increase of 26%.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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Publications (3)

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Cited By (6)

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• 1984
  • 1984-03-05 GB GB848405694A patent/GB8405694D0/en active Pending
• 1985
  • 1985-02-12 EP EP85300928A patent/EP0154425B1/fr not_active Revoked
  • 1985-02-12 DE DE8585300928T patent/DE3579926D1/de not_active Revoked
  • 1985-02-19 ZA ZA851261A patent/ZA851261B/xx unknown
  • 1985-03-05 JP JP60043562A patent/JPS60209015A/ja active Granted

Patent Citations (5)

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