US3577500A - Process for the production of polyamide fibres having high linear strength and knot strength - Google Patents

Process for the production of polyamide fibres having high linear strength and knot strength Download PDF

Info

Publication number
US3577500A
US3577500A US827018A US3577500DA US3577500A US 3577500 A US3577500 A US 3577500A US 827018 A US827018 A US 827018A US 3577500D A US3577500D A US 3577500DA US 3577500 A US3577500 A US 3577500A
Authority
US
United States
Prior art keywords
strength
polyamide
stretching
temperature
production
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US827018A
Inventor
Armin Kohler
Alfred Reichle
Klaus Offermann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE19681760539 external-priority patent/DE1760539C3/en
Application filed by Bayer AG filed Critical Bayer AG
Application granted granted Critical
Publication of US3577500A publication Critical patent/US3577500A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/58Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/60Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/78Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
    • D01F6/80Monocomponent 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)

Abstract

PROCESS FOR THE PRODUCTION OF POLYAMIDE FIBRES HAVING LINEAR STRENGTH AND KNOT STRENGTH BY STRETCHING POLYAMIDE MONOFILS AT TEMPERATURES OF 25 TO 35*C. BELOW THE TEMPERATURE LEVEL OF THE CRYSTALLITE MELTING MAXIMUM AT A RATIO OF 1:4.5 TO 1:6.5.

Description

Patented May 4, 1971 US. Cl. 264210 2 Claims ABSTRACT OF THE DISCLOSURE Process for the production of polyamide fibres having linear strength and knot strength by stretching polyamide monofils at temperatures of 25 to 35 C. below the temperature level of the crystallite melting maximum at a ratio of 124.5 to 116.5.
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.
It is well known that 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.
In order to obtain the desired optimum properties, this stretching must be carried out at an optimum stretching ratio within a reasonable narrowly limited temperature range. 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 of polyamide monofils at 30 to 40 C. below the melting point of the polyamides is also known.
It is an object of this invention to provide a process for the production of polyamide fibres which have high linear strength and knot strength which comprises stretching polyamide monofils obtained by the melt spinning process at temperatures of 25 to 35 C. below the temperature level of the crystallite melting maximum of the unstretched polyamide material to an extent of 1:4.5 to 126.5, said stretching being carried out within a contact time of 3 to 10 and preferably 4 to 8 seconds.
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 (DTA) 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. In the case of synthetic textile materials 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. Thus, 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.
Under optimum conditions with this apparatus a temperature difference AT of 005 C., which is equivalent to 2 v., could be detected. As previously indicated the reference temperature and not sample temperature was measured so that the temperatures shown on the DTA curves are reference temperatures. Sample temperature is simply determined from the following relationship.
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.
By 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.
The following table gives the crystallite melting points of polyamides and the stretching temperature.
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.
EXAMPLE 1 A polycaprolactam of 17, =3.l measured on a 0.1% solution in m-cresol at C. is spun from a melt spinning extruder through a single aperture or multiaperture spinneret into a Water bath. The spun product is drawn off at the rate of 20 m./min. and the diameter of the crude fibre is 0.50 mm. The temperature of the crystallite melting maximum, measured by means of DTA with a heating rate of 4 C./min., of the unstretched fibre is in the region of 233 C. The freshly spun fibre is passed directly from a dressing roller, where it is dressed with an oily preparation, to the heating assembly where it is stretched.
Stretching temperature200 C.
Stretching ratio-l :5 .1
Time of stay in the heating apparatus3.9 sec. Diameter of the stretched fibre0.22 mm.
Linear strength7.22i0.l6 gm./ denier Linear elongation-l5 i2% Knot strength-3.89i0.08 gm./ denier Intensity ratio 1(002) /I(200)0.04
(X-ray intensity measurement using Cu-Ka radiation) For comparison, stretching is carried out at 150 C. Polycaprolactam of 1;, =3.1 is spun and conveyed to the heating apparatus after application of the dressing, as described in Example 1. If the stretching temperature is kept below the temperature level of the crystallite melting maximum of the unstretched material, by more than 35 C. for example, at 170 C., and if the time of stay in the stretching apparatus is less than 3 seconds, the fibre obtained is considerably inferior in its linear strength and knot strength, as can be seen from the following summary:
Stretching temperature-l70 C.
Stretching ratio1:4.8
Time of stay in the heating apparatus1.8 sec. Diameter of the stretched fibre0.23 mm. Linear strength5 .78 $0.13 gm./ denier Linear elongation-21:3
Knot strength3.33 ;0.07 gm./ denier Intensity ratio I(002)/I(200)0.5
EXAMPLE 2 A copolyamide of 85% polyamide 6 and 15% polyamide 11 having a viscosity of =3.l measured on a tallite melting maximum of the unstretched fibre, measured by DTA with a heating rate of 4 C./min., is 218 C. The freshly spun fibre is dressed with an oily dressing and directly conveyed to the stretching apparatus.
Stretching temperaturel85 C.
Stretching ratio1:6.0
Time of stay in the heating apparatus5.5 sec. Diameter of the stretched fibre-0.20 mm. Linear strength-7.781016 gm./denier Linear elongation-17i2% Knot strength--4.56- -0.09 gm./ denier Intensity ratio 1(002) /I(200)-0.06
EXAMPLE 3 A copolyamide of polyamide 6, 10% polyamide 11 and 10% polyamide 12, having a viscosity of 1 =3.2 measured on a 0.1% solution in m-cresol at 25 C. is spun from a melt spinning extruder through a single aperture or multiaperture spinneret into a water bath. The draw-oflf rate is 10 m./min. and the diameter of the crude fibre 0.50 mm. The temperature of the crystallite melting maximum of the unstretched fibre, measured by DTA with a heating rate of 4 C. per min., is 217 C. The freshly spun fibre is dressed with an oily dressing and directly conveyed to the heating apparatus for stretching.
Stretching temperaturel C.
Stretching ratio--1:6.2
Time of stay in the heating apparatus5.2 sec. Diameter of the stretched fibre-0.20 mm. Linear strength-7.22:0.16 gm./ denier Linear elongation-18 i2% Knot strength4.67i0.09 gm./ denier Intensity ratio I(002)/I(200)0.03
What we claim is:
1. 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.
2. The process according to claim 1, wherein said stretching is carried out in a heating cupboard.
References Cited UNITED STATES PATENTS 6 FOREIGN PATENTS 648,412 9/1962 Canada 264-290 573,081 11/1954 Great Britain 264-210 5 DONALD J. ARNOLD, Primary Examiner H. MINTZ, Assistant Examiner Robertson 264--290 Hebeler 264-210 Cenzato 264-210 Stow et a1 57---140 264290N Alexander 264-290 10 U8. C1. X.R.
US827018A 1968-06-01 1969-05-22 Process for the production of polyamide fibres having high linear strength and knot strength Expired - Lifetime US3577500A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681760539 DE1760539C3 (en) 1968-06-01 Process for the production of polyamide monofilaments with high linear and knot strength

Publications (1)

Publication Number Publication Date
US3577500A true US3577500A (en) 1971-05-04

Family

ID=5696125

Family Applications (1)

Application Number Title Priority Date Filing Date
US827018A Expired - Lifetime US3577500A (en) 1968-06-01 1969-05-22 Process for the production of polyamide fibres having high linear strength and knot strength

Country Status (7)

Country Link
US (1) US3577500A (en)
JP (1) JPS523012B1 (en)
BE (1) BE733785A (en)
CH (1) CH516656A (en)
FR (1) FR2010019A1 (en)
GB (1) GB1206904A (en)
NL (1) NL6908114A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4338277A (en) * 1979-08-20 1982-07-06 Toray Industries, Inc. Process for producing high knot strength polyamide monofilaments
US5279783A (en) * 1992-01-30 1994-01-18 United States Surgical Corporation Process for manufacture of polyamide monofilament suture
US5349044A (en) * 1992-01-30 1994-09-20 United States Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4338277A (en) * 1979-08-20 1982-07-06 Toray Industries, Inc. Process for producing high knot strength polyamide monofilaments
US5279783A (en) * 1992-01-30 1994-01-18 United States Surgical Corporation Process for manufacture of polyamide monofilament suture
US5349044A (en) * 1992-01-30 1994-09-20 United States Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide
US5405358A (en) * 1992-01-30 1995-04-11 United States Surgical Corporation Polyamide monofilament suture
US5540717A (en) * 1992-01-30 1996-07-30 U.S. Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide

Also Published As

Publication number Publication date
CH516656A (en) 1971-12-15
NL6908114A (en) 1969-12-03
DE1760539A1 (en) 1971-12-30
FR2010019A1 (en) 1970-02-13
GB1206904A (en) 1970-09-30
BE733785A (en) 1969-11-03
JPS523012B1 (en) 1977-01-25
DE1760539B2 (en) 1976-06-24

Similar Documents

Publication Publication Date Title
US4228118A (en) Process for producing high tenacity polyethylene fibers
US3969462A (en) Polyester yarn production
US4276348A (en) High tenacity polyethylene fibers and process for producing same
SU1748653A3 (en) Apparatus for forming filaments from polymer melt
US4456575A (en) Process for forming a continuous filament yarn from a melt spinnable synthetic polymer
GB1168510A (en) Process for Melt-Spinning Polyamides
US2323383A (en) Production of artificial materials
US2957747A (en) Process for producing crimpable polyamide filaments
US4195161A (en) Polyester fiber
CA1037672A (en) Polyester yarn production
Grove et al. Exploratory experiments in the conversion of plasticized melt spun PAN-based precursors to carbon fibers
US3577500A (en) Process for the production of polyamide fibres having high linear strength and knot strength
NL8003494A (en) METHOD FOR MANUFACTURING MELTING SPUN AND ORIENTED CRYSTALLINE FILAMENTS
ES435306A1 (en) Process for high modulus polymeric materials
GB1168767A (en) Process for the Preparation of Synthetic Polymer Filaments.
JPH07501588A (en) Fine denier staple fiber
ATE83269T1 (en) METHOD AND DEVICE FOR THE MANUFACTURE OF POLYPROPYLENE THREADS.
RU2114939C1 (en) Threads based on polycaprolactam with relative viscosity of 2,0-3,0, method of their production, yarn and flat articles produced from these threads
FI58358C (en) FOERFARANDE FOER FRAMSTAELLNING AV TEXTURERAT POLYESTERGARN
US3841079A (en) Carbon filaments capable of substantial crack diversion during fracture
US4671754A (en) Apparatus for manufacturing porous polytetrafluoroethylene material
EP0126519A2 (en) Process for producing self-crimping polyester yarn
Jain et al. Oxidative stabilization of oriented acrylic fibres—morphological rearrangements
EP0140559B1 (en) Improved high speed process for forming fully drawn polyester yarn
GB1268302A (en) Process for the manufacture of crimped filaments of synthetic linear polyamides or copolyamides