Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J13/00—Heating or cooling the yarn, thread, cord, rope, or the like, not specific to any one of the processes provided for in this subclass
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G1/00—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
  • D02G1/20—Combinations of two or more of the above-mentioned operations or devices; After-treatments for fixing crimp or curl
  • D02G1/205—After-treatments for fixing crimp or curl
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics or fibrous goods made from such materials, e.g. by ultrasonic waves, corona discharge, irradiation, electric currents or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/006—Ultra-high-frequency heating

Definitions

• the present invention relates to a process for continuously heating, drying and heat-setting tows of filaments or fibers of synthetic polymers of high molecular weight.
• fibrous materials consisting of or containing synthetic polymers of high molecular weight, such as polyesters, polyamides, polyolefins or polyacrylonitrile must be heated during that part of the manufacturing process which follows the spinning process, for example before, during or after the drawing process.
• the fibers can be heated with the aid of contact heating, for example on hot rotating rolls or drums, with hot gases or vapors, with air or with hot liquids or melts. All these processes enable, however, only relatively thin layers of fibers to be heated rapidly enough and, above all, uniformly so that the fibers must be used in a stretched or slightly expanded form.
• the present invention provides a process for continuously heating, drying and heat-setting wet tows of filaments or fibers consisting of or containing synthetic polymers of high polymers of high molecular weight, such as polyesters, polyamides, polyolefins, or polyacrylonitrile, by passing said tows of filaments or fibers through an electric high frequency field. It is advantageous to use an electric high frequency field having an intensity in the range of from 0.2 to kilovolts/centimeter and a frequency of 2 to 60 megacycles. It has proved particularly advantageous, however, to use an electric high frequency field having an intensity of 1 to 1.5 kilovolts/centimeter and a frequency of 5 to 25 megacycles.
• the process according to the invention is especially suitable for heating, drying and heat-setting tows of crimped filaments or fibers, respectively, which are wet as they have left the crimping chamber and are not expanded or laid down.
• the tows of filaments are continuously passed between the plates of a plate condenser at the speed of the processing line of the sliver.
• a strong electric alternating field is generated, pref- 3,435,534 Patented Apr. 1, 1969 erably having a field strength of 0.2 to 5 kilovolts/centimeter, and more preferably of 1 to 1.5 kilovolts/centimeter.
• the frequency of the electric alternating field ranges of from 2 to -60 megacycles and advantageously 5 to 25 megacycles.
• the dielectric losses of wet tows of filaments involve a generation of heat within the tow of filaments. Thus the heat is not applied to the tow from the outside with formation of disturbing temperature gradients, but generated inside the tow itself.
• the drying and heat-setting of wet tows of filaments according to the invention is especially advantageous when the tows contain 4 to 20% of water, calculated on the weight of the wet tows, prior to the high frequency treatment.
• the amounts of humidity and treating agents always present in tows of filaments commonly considered to be dry provoke a dielectric absorption in the electric alternating tfield, so that also dry tows of filaments can be heated and, if desired, further dried and set. In this case, however, a longer time of treatment in the electric alternating field is required than for drying and heatsetting wet tows of filaments with a higher water content in the same electric alternating field.
• the process of the present invention offers the following advantages:
• the processing line of the sliver can be essentially shortened because drying and heat-setting take place simultaneously and the tow of filaments is densely pushed together.
• the simultaneity of drying and heat-setting involves a higher dyestuff absorption with otherwise identical textile properties. Owing to the wet crimping the closeness of the tow is improved.
• As the tow of filaments is not expanded after crimping a higher packing density in the container is obtained and simultaneously the discharge of the container, which is important for the further treatment, is improved.
• the process according to the invention permits a considerable economy in space and in the case of wet and crimped tows of filaments a higher packing density in the container, because relaying and expanding are no longer necessary, and a better cohesion of the tow.
• the process of the invention is not limited to tows of filaments of a definite size as the drying period at a given frequency substantially depends on the energy density of the electric field characterized by the electric field strength. Hence, it follows that with a sufficient power intensity of the generator the drying period does not increase with a higher amount of fibrous material to be dried per unit of time.
• the high frequency power of the generator required is hardly higher than that calculated from the specific heat of the fibrous material and of water and the vaporization heat of the water.
• EXAMPLE 1 (a) A tow of polyethylene terephthalate fibers having an individual titer of 3 deniers which, after spinning, had been shrunk by 41-42% at 97 C. was drawn in a ratio of 124.5 in superheated steam of about 190 C. The tow was then dried on drums of C., the circumferential speed of which was equal to that of the tow, and crimped in the dry state. The bundle of fibers was then slightly expanded to form a wavy band and heat-setting was performed for 60 seconds in superheated steam having a temperature of -185 C. at the outlet of the steam (sample 1a).
• the amount of dyestuff remaining in the bath was determined colorimetrically. The following dyestuff absorptions were found:
• a tow of polyethylene terephthalate fibers of the type specified above was likewise drawn in a ratio of 1:4.5, crimped in the wet state and then passed through the high frequency condenser in the state in which it left the crimping chamber as a bundle having a cross section of about 40 x 120 mm. After crimping the tow had a degree of humidity of 7%, calculated on the weight of the 4 moist tow.
• the applied field strength was 1.2 kilovolt/ centimeter with afrequency of 16 megacyclesrThe tow remained in the condenser for seconds.
• the shrinking values indicated under 2b reveal that besides drying a heat-setting analogous to Zn had taken place.
• a process for continuously heating, drying, and heatsetting Wet tows of filaments consisting of or containing synthetic polymers of high molecular weight which comprises passing the tows of filaments continuously through an electric high frequency field said tows being in the wet and crimped state in which they leave a crimping chamber without being expanded or laid down.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Artificial Filaments (AREA)
• Nonwoven Fabrics (AREA)
• Drying Of Solid Materials (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=7103375

Family Applications (1)

Country Status (9)

Cited By (2)

Citations (3)

• 1966
  • 1966-08-10 DE DE19661604532 patent/DE1604532A1/de active Pending
• 1967
  • 1967-06-27 US US649135A patent/US3435534A/en not_active Expired - Lifetime
  • 1967-08-03 NL NL6710719A patent/NL6710719A/xx unknown
  • 1967-08-04 ES ES343819A patent/ES343819A1/es not_active Expired
  • 1967-08-07 LU LU54255D patent/LU54255A1/xx unknown
  • 1967-08-07 CH CH1110067A patent/CH508753A/de not_active IP Right Cessation
  • 1967-08-07 GB GB36095/67A patent/GB1192397A/en not_active Expired
  • 1967-08-07 CH CH1110067D patent/CH1110067A4/xx unknown
  • 1967-08-08 AT AT735167A patent/AT293595B/de not_active IP Right Cessation
  • 1967-08-10 BE BE702528D patent/BE702528A/xx unknown

Patent Citations (3)

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