TREA

Process of making nylon flat yarns

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Information

  • Patent Grant
  • 5219503
  • Patent Number
    5,219,503
  • Date Filed
    Monday, November 4, 1991
    32 years ago
  • Date Issued
    Tuesday, June 15, 1993
    31 years ago
Information
Abstract
Flat continuous multifilament nylon apparel yarns suitable for critical dye applications and a process for making such yarns. The process for making the yarns includes spinning nylon polymer with a relative viscosity between about 35 and about 80 and stabilizing to make a feed yarn. The withdrawal speed in spinning is sufficiently high that highly uniform feed yarns are provided. In the process, feed yarn is drawn and subsequently relaxed, preferably in the form of a warp of yarns, so that the resulting drawn yarns have properties suitable for use as flat yarns and have excellent dye uniformity with large molecule acid dyes.
Description
Claims
  • 1. A process for making flat continuous multifilament nylon apparel yarns comprising:
  • spinning polyamide polymer having a relative viscosity (RV) between about 35 and about 80, said spinning being performed at a withdrawal speed (V.sub.s) sufficient to form spun yarn with a residual draw ratio (RDR).sub.S of less than about 2.75;
  • stabilizing, interlacing, and applying finish to said spun yarn to form a feed yarn having a residual draw ratio (RDR).sub.F between about 1.55 and about 2.25, said feed yarn having a dynamic length change (.DELTA.L) and shrinkage rate (.DELTA.L/.DELTA.T) which are both less than 0 between 40.degree. C. and 135.degree. C.;
  • dry drawing and subsequently dry relaxing said feed yarn to form drawn yarn, said dry drawing being performed at a draw ratio between about 1.05 and about (RDR).sub.F /1.25 and at a yarn draw temperature (T.sub.D) between about 20.degree. C. and about the Brill temperature (T.sub.II,**) of said polyamide polymer, said dry relaxing of said drawn feed yarn being performed at a yarn relaxation temperature (T.sub.R) between about 20.degree. C. and a temperature about 40.degree. C. less than the melting point (T.sub.M) of said polyamide polymer, said yarn relaxation temperature further being defined by the following equation:
  • T.sub.R (.degree.C.).ltoreq.[1000/(K.sub.1 -K.sub.2 (RDR).sub.D)]-273
  • wherein K.sub.1 =1000/(T.sub.II,L +273)+1.25K.sub.2 and K.sub.2 =[1000/(T.sub.II,L +273)-1000/T.sub.II,** +273)]/0.3, T.sub.II,L being the temperature associated with the breaking of hydrogen bonds in said polyamide polymer and T.sub.II,** being the Brill temperature of said polyamide polymer, said dry drawing and said dry relaxing being performed such that said drawn yarn has a boil-off shrinkage (BOS) between about 3% and about 10% and a residual draw ratio (RDR).sub.D between about 1.25 and about 1.8.
  • 2. A process for making flat continuous multifilament nylon apparel yarns comprising:
  • spinning polyamide polymer having a relative viscosity (RV) between about 35 and about 80, said spinning being performed at a withdrawal speed (V.sub.s) sufficient to form spun yarn with a residual draw ratio (RDR).sub.S of less than about 2.75;
  • stabilizing, interlacing, and applying finish to said pun yarn to form a feed yarn having a residual drawn ratio (RDR).sub.F between about 1.55 and about 2.25, said feed yarn having a dynamic length change (.DELTA.L) and shrinkage rate (.DELTA.L/.DELTA.T) which are both less than 0 between 40.degree. C. and 135.degree. C.;
  • dry drawing and subsequently dry relaxing a warp of said feed yarn to form a warp of drawn yarns, said dry drawing being performed at a warp draw ratio (WDR) between about 1.05 and about (RDR).sub.F /1.25 and at a yarn draw temperature (T.sub.D) between about 20.degree. C. and about the Brill temperature (T.sub.II,**) of said polyamide polymer, said dry relaxing of said warp of drawn feed yarns being performed at a yarn relaxation temperature (T.sub.R) between about 20.degree. C. and a temperature about 40.degree. C. less than the melting point (T.sub.M) of said polyamide polymer, said yarn relaxation temperature further being defined by the following equation:
  • T.sub.R (.degree.C).ltoreq.[10000/(K.sub.1 -K.sub.2 (RDR).sub.D)]-273
  • wherein K.sub.1 =1000/(T.sub.II,L +273)]/0.3, T.sub.II,L being the temperature associated with the breaking of hydrogen bonds in said polyamide polymer and T.sub.II,** being the Brill temperature of said polyamide polymer, said dry drawing and said dry relaxing being performed such that said warp of drawn yarns have a boil-off shrinkage (BOS) between about 3% and about 10% and a residual draw ratio (RDR).sub.D between about 1.25 and about 1.8.
  • 3. The process as set forth in claim 1 or 2 wherein said withdrawal speed in said spinning is such that the residual draw ratio (RDR.sub.S) of the said spun yarn is less than 1.5, wherein said dry drawing and said dry relaxing are performed in an inert gaseous atmosphere of about 50% to about 90% relative humidity (RH), and wherein said dry relaxing is performed using a percent overfeed (OF) of less than about 10%.
  • 4. The process as set forth in claim 1 or 2 wherein said withdrawal speed in said spinning is such that the residual draw ratio (RDR.sub.s) of the said spun yarn is less than 2.25, wherein said dry drawing and said dry relaxing are performed in an inert gaseous atmosphere of about 50% to about 90% relative humidity (RH), and wherein said dry relaxing is performed using a percent overfeed (OF) of less than about 10%.
  • 5. The process of claim 1 or 2 wherein said withdrawal speed in said spinning is such that the residual draw ratio (RDR.sub.s) of the said spun yarn is less than 2.0, wherein said dry drawing and said dry relaxing are performed in an inert gaseous atmosphere of about 50% to about 90% relative humidity (RH), and wherein said dry relaxing is performed using a percent overfeed (OF) of less than about 10%.
  • 6. The process as set forth in claim 1 or 2 wherein said spinning and said stabilizing are performed such that said feed yarn has a draw tension in grams per original denier at 33% extension (DT.sub.33%) less than about 1.2 g/d.
  • 7. The process as set forth in claim 1 or 2 wherein said spinning and said stabilizing are performed such that said feed yarn has a draw tension in grams per original denier at 33% extension (DT.sub.33%) less than about 1.0 g/d.
  • 8. The process as set forth in claim 5 wherein said spinning and said stabilizing are performed such that said feed yarn has a thermal mechanical analysis (TMA) maximum dynamic extension rate (.DELTA.L/.DELTA.T)max, between about 0.05 and about 0.15 %/.degree.C. and a change in (.DELTA.L/.DELTA.T) max with stress (.sigma.) [=d(.DELTA.L/.DELTA.T)max/d.sigma.] between about 3.times.10.sup.-4 and about 7.times.10.sup.-4 (%/.degree.C./)(mg/d).
  • 9. The process as set forth in claim 5 wherein said spinning and said stabilizing are performed such that said feed yarn has a draw stress (.sigma..sub.D) between about 1.0 and about 2.0 g/dd, a draw modulus (M.sub.D) between about 3 and about 7 g/dd, and an apparent draw energy (E.sub.D) a between about 0.2 and about 0.6 (g/dd)/.degree.K., wherein g/dd represents grams per drawn denier.
  • 10. The process as set forth in claim 1 or 2 wherein said dry drawing is performed at a draw temperature (T.sub.D) between about 20.degree. C. and about the temperature associated with the breaking of hydrogen bonds in said polyamide (T.sub.II,L).
  • 11. The process as set forth in claim 1 or 2 wherein said dry drawing is performed at draw temperature (T.sub.D) between about 20.degree. C. and 90.degree. C.
  • 12. The process as set forth in claims 1 or 2 wherein dry relaxing is performed at a relaxation temperature (T.sub.R) less than about the temperature associated with the onset of major crystallization (T.sub.II,*).
  • 13. The process as set forth in claims 1 or 2 wherein dry relaxing is performed at a relaxation temperature (T.sub.R) less than about the temperature associated with the breaking of hydrogen bonds in said polyamide (T.sub.II,L).
  • 14. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises nylon 66 polymer.
  • 15. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing bifunctional polyamide comonomer units or non-reactive additive capable of hydrogen bonding with the 66 polymer.
  • 16. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing epsilon-caproamide comonomer units.
  • 17. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing 2-methyl-pentamethylene adipamide comonomer units.
  • 18. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing by weight about 2% to about 8% epsilon-caproamide comonomer units.
  • 19. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing by weight about 2% to about 20% 2-methyl-pentamethylene adipamide comonomer units.
  • 20. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing epsilon-caproamide comonomer units and 2-methyl-pentamethylene adipamide comonomer.
  • 21. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises a homopolymer of epsilon-caproamide units.
  • 22. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises nylon 66 polymer and wherein K.sub.1 is 4.95 and K.sub.2 is 1.75.
  • 23. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing by weight about 2% to about 8% epsilon-caproamide comonomer units and wherein K.sub.1 is 4.95 and K.sub.2 is 1.75.
  • 24. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises polymer of nylon 66 containing by weight about 2% to about 10% of 2-methylpentamethylene adipamide comonomer units and wherein K.sub.1 is 4.95 and K.sub.2 is 1.75.
  • 25. The process as set forth in claim 1 or 2 wherein said nylon polymer comprises epsilon-caproamide units and wherein K.sub.1 is 5.35 and K.sub.2 is 1.95.
  • 26. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that the boil-off shrinkage (BOS) of said drawn yarns is between about 3% and about 8% and the residual draw ratio of said drawn yarns (RDR).sub.D is between about 1.25 and about 1.55.
  • 27. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that the boil-off shrinkage (BOS) of at least a portion of the said drawn yarns is less than about 8% and that the boil-off shrinkage (BOS) of other portion of said drawn yarns is greater than about 8% such that said drawn yarns having a difference in percent boil-off shrinkage (BOS) of at least 4% and the residual draw ratio of said drawn yarns (RDR).sub.D is between about 1.25 and about 1.55.
  • 28. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that the dye transition temperature (T.sub.dye) of said drawn yarns is less than about 65.degree. C. and the residual draw ratio of said drawn yarns (RDR).sub.D is between about 1.25 and about 155.
  • 29. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that the dynamic loss modulus peak temperature (T.sub.E"max) of said warp drawn yarns is less than about 100.degree. C. and the residual draw ratio of said drawn yarns (RDR).sub.D is between about 1.25 and about 1.55.
  • 30. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that resulting warp of drawn yarns provides a large molecule dye uniformity rating (LMDR) of at least about 6.5.
  • 31. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing and performed such that resulting warp of drawn yarns provides a large molecule dye uniformity rating (LMDR) of at least about 6.
  • 32. The process as set forth in claim 1 or 2 wherein said spinning and stabilizing and said dry drawing and dry relaxing are performed such that resulting warp of drawn yarns provide a large molecule dye uniformity rating (LMDR) of at least about 7.0.
  • 33. A process as set forth in claim 2 wherein the said warp of feed yarns is comprised of feed yarns of different nylon polymers.
BACKGROUND OF THE INVENTION

This is a continuation-in-part of application Ser. No. 07/541,692 filed Jun. 21, 1990, now abandoned. The present invention relates to improved continuous multifilament nylon apparel yarns and more particularly relates to a warp-draw process for making nylon flat yarns and improved yarn products made thereby. Nylon flat yarns are used in a variety of woven and warp knit fabrics which are dyed before use. When small molecule dyes are used for these fabrics, uniform dyeing can usually be achieved without great difficulty. However, for some critical dye applications such as fabrics for swimwear and auto upholstery which require excellent wash and/or light fastness, it is desirable to use large molecule acid dyes. In dyeing these fabrics with large molecule acid dyes, even a small amount of non-uniformity in dye uptake of the flat yarns can result in highly-visible non-uniformity in fabric dyeing and thus poor fabric appearance. Nylon flat yarns generally have break elongations of less than about 60% and thus may be referred to as "fully drawn" yarns. Typically, the high degree of orientation in known flat yarns is imparted by drawing during yarn manufacture in an integrated spin-draw process (speed of withdrawal from the spinneret of between about 1400 and 2000 meters per minute (mpm) and wind-up speeds of between about 2500 and 3500 mpm) or in a split process in which a package of yarn spun at a withdrawal speeds of typically less than 1000 mpm is drawn in a separate process using a single-end draw winder. However, the yarns so produced have often been found to be undesirable for critical dye applications such as swimwear or auto upholstery due to the great care that must be taken during the preparation of such yarns and during the preparation and dyeing of the resulting fabrics to achieve acceptable dye uniformity. Equipment has been sold which is capable of drawing of a warp of nylon yarns in a hot water bath. However, while processes using this equipment can increase dye uniformity, the equipment is recognized to have a number of inherent disadvantages. Processes using the equipment are messy and produce a waste stream of polluted water since the yarn finish is removed into water during drawing. Moreover, for use of the yarn in knitting, a finish must be reapplied after drawing. Another serious drawback of equipment which has been sold for wet drawing is that the speed of the process is typically limited to approximately 300-350 mpm by the limited capacity of the equipment to dry the yarns before wind-up. In accordance with the invention, flat continuous multifilament nylon apparel yarns especially suitable for critical dyed applications and a process for making such yarns are provided. The process for making the yarns includes: spinning nylon polymer having a relative viscosity (RV) between about 35 and about 80, the spinning being performed at a withdrawal speed (V.sub.s) sufficient to form spun yarn with a residual draw ratio (RDR).sub.s of less than about 2.75; stabilizing, interlacing, and applying finish to the spun yarn to form a feed yarn having a residual draw ratio (RDR), between about 1.55 and about 2.25, the feed yarn having a dynamic length change (.DELTA.L) and shrinkage rate (.DELTA.L/.DELTA.T) which are both less than 0 between 40.degree. C. and 135.degree. C.; dry drawing and subsequently dry relaxing the feed yarn to form drawn yarn, the dry drawing being performed at a draw ratio between about 1.05 and about (RDR).sub.F /1.25 and at a yarn draw temperature (T.sub.D) between about 20.degree. C. and about the temperature T.sub.II,** of said polyamide polymer, the dry relaxing of the drawn feed yarns being performed at a yarn relaxation temperature (T.sub.R) between about 20.degree. C. and a temperature about 40.degree. C. less than the melting point (T.sub.M) of the polyamide polymer, the relaxation temperature further being defined by the following equation: In a preferred form of the invention, the dry drawing and dry relaxing are performed on a warp of said feed yarns. For feed yarns of nylon 66 polymers, a preferred relaxation temperature range for a given residual draw ratio of the drawn yarns (RDR).sub.D may be obtained by assigning a value of 4.95 to K.sub.1 and 1.75 to K2 in the equation above. For nylon 6 polymers, a K.sub.1 of 5.35 and K.sub.2 of 1.95 are suitable values to obtain a preferred temperature range. In accordance with one preferred process, the withdrawal speed in spinning is sufficiently high that the residual draw ratio of the spun yarn is less than about 2.5. In another preferred form of the invention, the spinning speed of the yarn as spun imparts a residual draw ratio of less than 2.25, most preferably, less than 2.0. Usually, a spun yarn with this residual draw ratio has a dynamic length change (.DELTA.L) and shrinkage rate (.DELTA.L/.DELTA.T) which are both less than 0 between 40.degree. C. and 135.degree. C. Thus, the spinning at the sufficiently high speed thereby stabilizes the spun yarn without additional stabilization treatments and then the yarn as spun can be used as the feed yarn. In accordance with another preferred process in accordance with the invention, the spinning and the stabilizing are performed such that the feed yarn has a draw tension (DT.sub.33%) less than about 1.2 g/d, especially less than about 1 g/d. In the process of the invention, dry drawing and dry relaxing of the feed yarns is performed, preferably in the form of a warp of yarns treated simultaneously. Preferably, the dry drawing and dry relaxing is done in an inert gaseous atmosphere, e.g., air, of about 50% to about 90% relative humidity (RH), more preferably, about 60% to about 80% RH. In the dry relaxation, a relaxation temperature less than about T.sub.II,*, especially less than T.sub.II,L, is used. Preferred conditions in the relaxation result in a boil-off shrinkage (BOS) of the drawn yarns of between about 3% and about 8% and a residual draw ratio (RDR).sub.D of the drawn yarns of between about 1.25 and about 1.55. Preferably, the process produces yarns with a dye transition temperature T.sub.dye of less than about 65.degree. C. The process in accordance with the invention is useful for most nylon polymers. Preferred nylon polymers include nylon 66 polymer and nylon 6 polymer. Especially preferred nylon polymers are nylon 66 containing a minor amount of bifunctional polyamide comonomer units or non-reactive additive capable of hydrogen bonding with the nylon 66 polymer. In accordance with the invention, a flat multifilament apparel yarn of nylon 66 polyamide polymer is provided. The polymer of the fiber has a melting point (T.sub.M) between about 245.degree. C. and about 265.degree. C., is of relative viscosity (RV) between about 50 and about 80 with about 30 to about 70 equivalent NH2-ends per 10.sup.6 grams of polymer. The multifilament apparel yarn is further characterized by a residual draw ratio (RDR).sub.D between about 1.25 and about 1.55 with an initial modulus greater than about 15 g/d, a boil-off shrinkage (S) between about 3% and about 10%, a C.I. Acid Blue 122 dye transition temperature (T.sub.dye) less than about 65.degree. C., a C.I. Acid Blue 40 apparent dye diffusion coefficient (D.sub.A), measured at 25.degree. C., of at least about 20.times.10.sup.-10 cm/sec, and apparent pore mobility (APM) greater than about [5-0.37.times.10.sup.-4 APV], wherein the apparent pore volume (APV) is greater than about 4.times.10.sup.4 cubic angstroms. In a preferred form of the invention, the apparent pore mobility is greater than about 2. The process of the invention provides highly uniform nylon yarns which are useful in a wide variety of warp knit and woven fabrics which must be uniformly dyeable with large molecule dyes. Yarns in accordance with a preferred form of the invention are especially well suited for this use and have a large molecule dye uniformity rating (LMDR) of at least about 6.

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Entry
Mayer warp drawing machine developed further, Man-Made Fiber Year Book (CTI), 1986, pp. 104-105.
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Draw-warping and draw-warp-sizing system for POY and undrawn yarns, R. C. Mears, Man-Made Fiber Year Book (CTI) 1986, pp. 108-110.
Draw Warping-Draw Sizing-Four Years of Practical Experience, B. Bogucki-Land, Karl Mayer Textilmaschinenfabrik GmbH (undated).
Warp-drawing-sizing progress reviewed, R. C. Mears, Cora Engineering, Switzerland, Textile Month, Sep. 1987, pp. 108-111.
Draw warping combines processes, cuts costs, McAllister Isaacs III, Textile World, May 1985, p. 53.
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Continuation in Parts (1)
Number Date Country
Parent 541692 Jun 1990