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
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
  • D01F6/80—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from copolyamides

Definitions

• the invention concerns a process for the production of polyamide fibres which have high linear strength and knot strength, in which the monofils obtained by the melt spinning process are stretched at high temperatures.
• homopolyamides and copolyamides can be spun from spinning apparatus through fine spinning dies to form threads and fibres. It is also known that the mechanical and textile properties of the threads and fibres can be substantially improved by stretching.
• Polyamide fibres may, for example, be spun from a melt extruder through spinning dies into a water bath of to 80 C. and conveyed to a stretching apparatus where they are stretched to a multiple of their original length, so that they are given on an average good linear and knot strength values.
• Stretching is carried out by passing the polyamide fibres through a heating cupboard which can be heated with continuous temperature variations to 280 C.
• the temperature level of the crystallite melting maximum of the polyamide is determined by differential thermoanalysis (DTA) with a heating rate of 4 C. per minute.
• Differential thermal analysis is a dynamic method whereby the phase transitions and chemical transformations that occur during the heating of a polymeric or other material may be detected.
• the detectable thermal changes include the fusion peaks (crystalline melting maximums).
• the apparatus used features atmosphere control by diffusion into and out of sample holder cells.
• a metal sample holder fitted With thermocouples is suspended in the ceramic core of a standard combustion furnace from a rod attached to a metal plate. With the holder in position, the metal plate rests on the top of the vertically positioned furnace completely covering the opening but the furnace tube remains open at the bottom. Chromel- Alumel thermocouples of 28 gage wire are introduced through the base of the holder and cemented in a fixed position.
• the EMF representing the temperature difference is amplified by a L & N DC amplifier No. 9835-B. Temperature was measured in the reference substance, calcined alumina (at-A1 0 in a separate well and the rate control thermocouple was located in the outer wall of the sample holder. The signals for the differential temperature and the reference temperature were recorded on time-base chart recorders using two 10 in. single pen recorders (Leeds and Northrup instrument). The rate of heating was controlled by a cam-operated temperature programmer (West Instrument Co.).
• the atmosphere is controlled by discharging the desired gas or gases under pressure into the open end of the furnace at flow rates of 3,000 to 6,000 cc./min. via a metal coil gas spreader.
• the sample holder is blanketed with the gas and the atmosphere within the same well is achieved by diffusion of gas into the well.
• the removal of volatile products arising from the thermal degradation of the sample during a run is apparently accomplished by the driving force accompanying volatilization and is also dependent on diffusion.
• T sample T ref+AT Fiber, fabric, and some bulk polymer samples of 5 to 50 mg. can be run at heating rates of 1 to 10 C./min. from about 50 to 650 C.
• Samples are usually prepared by cutting into small squares of in. or in. lengths. The usual method for DTA sample preparation involves grinding or milling to 40-200 mesh. Samples are run in an atmosphere of purified nitrogen to provide nonoxidizing conditions.
• the sample packing technique involved the dilution of all samples with the alumina used as the reference material, so that the packing and thermal properties will be determined principally by the reference material regardless of sample shrinkage, melting, decomposition, etc.
• a modified sandwich packing developed in previous studies, was used in the present work. About one-third of the reference material to be used is deposited in the sample well as a base layer. The cut pieces of sample are then placed around the thermocouple junction together with reference material and the balance of the reference material constitutes a covering layer.
• DTA curves of drawn and undrawn nylon in nitrogen on the gas diffusion apparatus can be prepared. There is a well-defined endothermic peak for polymer fusion indicating the melting point.
• the fusion peak for the drawn fiber is much larger and sharper than the undrawn indicating a higher degree of crystallinity and/or orientation, as might be expected.
• polyamide fibres are to be understood polyamide monofils which have a diameter, after stretching of below 1.50 mm.
• the improvement in the properties achieved by the process according to the invention can also be determined by the intensity ratios on the X-ray diagram (determination according to Deby-Scherrer with copper-Km radiation).
• the monofils stretched by the known processes generally show an intensity ratio of I (002)/I (200) of between 0.10 and 1.00.
• (002) is the meridianial reflex and (200) the equatorial reflex, which is a measure of the arrangement of the molecular chains within a grid 3 plane. It was found that the products produced by the process of the invention have intensity ratio values of 0.03 to 0.08.
• 0.1% solution in m-cresol at 25 C. is spun from a melt spinning extruder into a waterbath through a single aperture or multiaperture spinning die.
• the draw-off rate is m./min. and the diameter of the crude fibre is 0.50 mm.
• the temperature of the crys- The following examples are to further illustrate the invention without limiting it.
• the freshly spun fibre is dressed with an oily dressing and directly conveyed to the stretching apparatus.
• a process for the production of polyamide fibers of high linear strength and knot strength which comprises stretching melt-spun polyamide monofils selected from the group consisting of polyamide-6, polyamide-66, polyamide-11, polyamide-l2, copolyamide-6/11, and copolyamide-6/ 11/ 12 at temperatures of 25-35 C. below the temperature level of the crystalline melting maximum as measured by differential thermal analysis with a heating rate of 4 C. per minute of the unstretched polyamide material to an extent in the range of 1:45 to 1:65 said stretching being carried out within a contact time of 3-10 seconds.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=5696125

Family Applications (1)

Country Status (7)

Cited By (3)

• 1969
  • 1969-05-05 CH CH682369A patent/CH516656A/de not_active IP Right Cessation
  • 1969-05-09 GB GB23709/69A patent/GB1206904A/en not_active Expired
  • 1969-05-22 US US827018A patent/US3577500A/en not_active Expired - Lifetime
  • 1969-05-28 NL NL6908114A patent/NL6908114A/xx unknown
  • 1969-05-29 BE BE733785D patent/BE733785A/xx unknown
  • 1969-05-30 JP JP44041804A patent/JPS523012B1/ja active Pending
  • 1969-05-30 FR FR6917904A patent/FR2010019A1/fr not_active Withdrawn

Also Published As

Similar Documents