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
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
  • D02J1/229—Relaxing
• • 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
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/08—Interlacing constituent filaments without breakage thereof, e.g. by use of turbulent air streams

Definitions

• 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
• 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.
• 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
• 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.
• Equipment has been sold which is capable of drawing of a warp of nylon yarns in a hot water bath.
• flat continuous multifilament nylon apparel yarns especially suitable for critical dyed applications and a process for making such yarn are provided.
• the process for making the yarns includes:
• RDR residual draw ratio
• ⁇ L dynamic length change
• ⁇ L/ ⁇ T shrinkage rate
• the dry drawing being performed at a draw ratio between about 1.05 and about (RDR) F /1.25 and at a yarn draw temperature (T D ) between about 20°C and about the temperature T II,** of said polyamide polymer
• the dry relaxing of the drawn feed yarns being performed at a yarn relaxation temperature (T R ) between about 20°C and a temperature about 40°C less than the melting point (T M ) of the polyamide polymer, the relaxation temperature further being defined by the following equation:
• T R (°C) ⁇ [1000/(K 1 - K 2 (RDR) D )] - 273 wherein K 1 1000/(T II,L + 273) + 1.25K 2 and K 2 - [1000/(T II,L + 273) - 1000/(T II,** + 273)]/0.3.
• the temperature T II,L and T II,** are determined by measuring the % change in length versus temperature at constant tension as will be explained in more detail).
• the dry drawing and the dry relaxing are performed such that the drawn yarn has a boil-off shrinkage (BOS) between about 3% and about 10% and a residual draw ratio (RDR) D between about 1.25 and about 1.8.
• BOS boil-off shrinkage
• RDR residual draw ratio
• the dry drawing and dry relaxing are performed on a warp of said feed yarns.
• a preferred relaxation temperature range for a given residual draw ratio of the drawn yarns (RDR) D may be obtained by
• the withdrawal speed in spinning is sufficiently high that the residual draw ratio of the spun yarn is less than about 2.5.
• the spinning speed of the yarn as spun imparts a residual draw ratio of less than 2.25, most preferably, less thsn 2.0.
• a spun yarn with this residual draw ratio has a dynamic length change ( ⁇ L) and shrinkage rate ( ⁇ L/ ⁇ T) which are both less than 0 between 40°C and 135°C.
• the spinning and the stabilizing are performed such that the feed yarn has a draw tension (DT 33% ) less than about 1.2 g/d, especially less than about 1 g/d.
• dry drawing and dry relaxing of the feed yarns is performed, preferably in the form of a warp of yarns treated simultaneously.
• 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.
• an inert gaseous atmosphere e.g., air
• RH relative humidity
• T 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) D of the drawn yarns of between about 1.25 and about 1.55.
• BOS boil-off shrinkage
• RDR residual draw ratio
• the process produces yarns with a dye transition temperature T dye of less than about 65°C.
• nylon polymets 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.
• the multifilament apparel yarn of nylon 66 polyamide polymer is provided.
• the polymer of the fiber has a melting point (T M ) between about 245°C and about 265°C, is of relative viscosity (RV) between about 50 and about 80 with about 30 to about 70 equivalent NH2-ends per 10 6 grams of polymer.
• the multifilament apparel yarn is further characterized by a residual draw ratio (RDR) 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 DYE ) less than about 65°C, a C.I. Acid Blue 40 apparent dye
• D A diffusion coefficient
• APM apparent pore mobility
• 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
• LMDR uniformity rating
• Figure 1 is a diagrammatical view of equipment useful for making a feed yarn in a process in accordance with the present invention.
• Figure 2 is a diagrammatical view of typical commercial warp-draw equipment useful in a process in accordance with the present invention.
• Figure 3 is a typical plot (line A) of draw tension (DT) and the corresponding plot (line B) of the along-end draw tension variation (DTV), at room
• DR temperature versus draw ratio
• E percent elongation
• RDR residual draw ratio
• Figure 4 are representative plots of percent change in length ( ⁇ length, %) of a nylon feed yarn versus temperature obtained using the Du pont Thermal Mechanical Analyser at a constant heating rate of 50°C per minute and varying the initial pre-tension from 3 mg/denier to 500 mg/denier; wherein, the yarn extends under tensions
• Figure 5 is representative plots of the dynamic extension rate, ( ⁇ L/ ⁇ T), versus temperature for a nylon feed yarn under pre-tensions of 50 to 500 mg/d obtained using the Du pont Thermal Mechanical Analyser at a
• Figure 6 is representative plots of the dynamic extension rate ( ⁇ L/ ⁇ T)max versus pre-tension stress ( ⁇ ), as described in Figure 5; wherein, the slope,
• d( ⁇ L/ ⁇ T)max/d( ⁇ ) at 300 mg/d is taken as a measure of the sensitivity of the drawn feed yarn during the relaxation step to varying stress levels (i.e., to varying %
• Figure 7 is a typical plot (line A) of the percent change in length ( ⁇ Length, %) of a nylon feed yarn versus temperature obtained using a Du Pont Thermal Mechanical Analyser at a pre-tension of 300 mg/d; and the corresponding plot (line B) of the dynamic extension rate defined by the instantaneous change in length per degree centigrade ( ⁇ Length, %)/( ⁇ Temperature, °C)- of line A.
• Figure 8 is a representative plot of the
• Figure 9 is a graphical representation of the reciprocal of the relaxation temperature (T R , °C), as given by the 1000/(T R + 273), versus the residual draw ratio of the drawn yarns (RDR) D .
• the regions I (ABDE) andd II (AEHI) enclosed by heavy lines illustrate temperature conditions in the relaxation step (T R ) as related to the drawing step (RDR) D of the process useful to produce yarns with excellent large molecule dye uniformity ratings
• Figure 10 (Line A) is a plot of dynamic shrinkage tension (ST), under constant length conditions at a heating rate of 30°C per minute versus temperature, which increases sharply at temperature T g and reaches a maximum at T ST, max; and Line B is the corresponding derivative, d(ST)/d(T), of the dynamic shrinkage tension (ST) versus temperature (T) plot (Line A).
• the derivative plot (B) exhibits minimum values which correspond
• Figure 11 is a typical plot of dry heat shrinkage measured using the Lawson-Hemphill TYT by increasing temperatures stepwise from 70°C to 150°C.
• Figure 12 is a typical plot of the logarithm of the dynamic modulus (E') versus temperature (line A) and of the corresponding logarithm of the Tan Delta versus temperature (line B).
• Figure 13 is a typical plot of the change in heat flow versus temperature as measured by Differential Scanning Calorimetry (DSC).
• DSC Differential Scanning Calorimetry
• Figures 14 and 15 are typical plots of the TMA dynamic extension rate versus temperature for drawn yarns; wherein the drawn yarns of Figure 14 have a LMDR less than 6 and those of Figure 15 have a LMDR greater than 6.
• Figure 16 is a representative plot of the residual draw ratio of as-spun nylon 66 yarns (RDR) S expressed by its reciprocal, 1/(RDR) S , (line A) and of density (line B) versus spin speed.
• Figure 17 is a representative plot of the length change after boil-off of freshly as-spun yarns (line A) and of birefringence (line B) versus spin speed.
• Figure 18 is a representative TMA plot of the dynamic extension rates ( ⁇ L/ ⁇ T) under a 300 mg/d tension versus temperature for various spun-oriented and partial drawn yarns used in the Examples as feed yarns for warp drawing.
• Figure 19 is a representative TMA plot of shrinkage ( ⁇ Length, %) versus temperature under a 5 mg/d tension for different yarn types.
• Figure 20 is a representative plot of draw stress ( ⁇ D ), expressed as a grams per drawn denier (g/dd), versus draw ratio at 20°C, 75°C, 125°C, and 175°C;
• the slope is called the draw modulus (M D ) and is defined by ( ⁇ D / ⁇ DR).
• Figure 21 compares the draw stress ( ⁇ D ) versus draw ratio (DR) at 75°C for various feed yarns.
• Figure 22 is a representative plot of the logarithm of draw modulus, ln(M D ), versus [1000/(T D , °C + 273)] for the feed yarn in Figure 21; wherein, the slope is taken as a measure of the draw energy (E D ).
• Figure 23 is a representative plot of percent dye exhaustion (%E) for C.I. Acid Blue 122 versus dye temperature (°C) with an increase in dye exhaustion occurring at about 57-58°C which corresponds to the dye bath temperature to reach about 15% exhaustion referred herein to as the dye transition temperature, T DYE .
• Figure 23 (Line B) is a corresponding plot of Line A expressed as percent exhaustion on a logarithimic scale versus the reciprocal of the dye bath temperature expressed as
• Figure 24 is a representative plot of dye bath exhaustion curves similar to Figure 23 (Line A), versus temperature for four drawn yarns made from Feed Yarn "G" in Table I.
• Figure 25 is a representative plot of measured dye rate (S 25 ) using a large molecule acid dye C.I. Acid
• Figure 26 is a plot of the Apparent Pore
• ACM Apparent Pore Volume
• Figures 27-36 are computer generated simulations of fabric streaks useful as a guide to determine the LMDR of yarns produced in the examples of this application.
• Nylon polymer as used in this application refers to any of the various generally linear, aliphatic
• nylon polymers are poly(hexamethylene adipamide) (nylon 66) and poly(s-caproamide) (nylon 6).
• the nylon polymer has a relative viscosity (RV) when spun of between about 35 and about 80.
• nylon 66 polymer When nylon 66 polymer is used, it is
• the RV of the polymer is greater than about 46 as taught in U.S. Reissue Patent No. 33,059 (U.S. Patent No. 4,583,357), the disclosure of which is hereby incorporated by reference.
• the RV usually should be less than about 65 since the advantages obtained in accordance with Reissue Patent 33,059 do not increase significantly at above an RV of 65.
• nylon 66 it is advantageous to use nylon 66 including a minor amount of one or more different copolymer units such as s-caproamide and/or 2-methyl-pentamethylene adipamide (Me5-6) or an unreactive additive capable of hydrogen bonding with the nylon 66.
• comonomer capable of hydrogen bonding with the 66 nylon polymer can be prepared by condensation polymerization in an aqueous "salt" solution containing the monomers in appropriate proportions. Procedures useful for the production of homopolymer nylon 66 can be applied to the production of the N6,66 with s-caprolactam added to the salt solution.
• adipic acid with hexamethylene diamine (HMD) and 2-methyl-pentamethylene diamine (MPMD) in the molar proportions necessary to produce the copolymer with the desired weight percent 2-methyl-pentamethylene adipamide is used to make the salt solution.
• HMD hexamethylene diamine
• MPMD 2-methyl-pentamethylene diamine
• 2-methyl-pentamethylene diamine is commercially available and is sold by E. I. du Pont de Nemours & CO., Wilmington, Delaware, under the trademark DYTEK A®.
• yarn Y is spun from spinneret 1 using a high speed melt
• the filaments are cooled in a "quench” chimney using cross-flow air at, for example, 20°C, and are converged at a finish applicator such as a roll or metered finish applicator.
• the withdrawal speed (V s ), i.e., the speed of the first roll which acts to pull the yarn away from the spinneret 1, is sufficient to form spun yarn with a
• RDR residual draw ratio
• E B elongation to break in %
• the residual draw ratio (RDR) S must be less than 2.75 in the spun yarn and be combined with the other steps of the process of the method to obtain the improved large molecule dye uniformity in the drawn yarns.
• the residual draw ratio (RDR) S is less than about 2.5 in the spun yarn, most preferably less than about 2.25.
• the withdrawal speed at which the residual draw ratio of less than 2.75 is imparted to the spun yarn depends on a number of factors in the spinning process including the fineness (denier per filament) of the yarns being spun, the relative viscosity of the polymer, the spinning temperature, spinneret capillary dimensions, and the efficiency of the quench as determined by the quench air flow pattern, flow rate, and quench air temperature.
• a typical minimum withdrawal speed to impart a residual draw ratio (RDR) S of less than 2.75 is on the order of about 2000 mpm for normal textile yarns. In general, it is preferable to spin the feed yarns at withdrawal speeds above about 3000 mpm where it is not as necessary to carefully control process conditions.
• the spun yarn is stabilized to provide a feed yarn having residual draw ratio (RDR) F of between about 1.55 and about 2.25 and a dynamic length change ( ⁇ L) and shrinkage rate ( ⁇ L/ ⁇ T) which are both less than 0 between 40°C and 135°C.
• RDR residual draw ratio
• ⁇ L dynamic length change
• ⁇ L/ ⁇ T shrinkage rate
• the feed yarn has a residual draw ratio (RDR) f of between about 1.55 and about 2.0.
• stabilization may be performed by means of a number of different alternatives. Stabilization can be accomplished as indicated in alternative A by exposing the spun yarn to steam in a steam chamber 4 as disclosed in U.S. Patent No. 3,994,121 or passing the yarn through a steamless, heated tube as disclosed in U.S. 4,181,697. The yarn then passes through puller and letdown rolls, 5 and 6, respectively, although it is not drawn to any substantial extent.
• Alternative B indicates a set of puller and letdown rolls 5 and 6 which are driven at essentially the same speed as the wind-up and thus there is no substantial drawing of the yarn between these rolls and the windup.
• Stabilization is thereby imparted by the high spinning speed as in alternative C, e.g., greater than about 4000 mpm.
• the rolls 5 and/or 6 could be heated if desired for the purpose of stabilizing the yarn shrinkage if spun at speeds lower than approximately 4000 mpm.
• Alternative C is a "godetless" process in which the yarn is not
• the yarns are interlaced at interlace jet 9 so that the feed yarn has a sufficient degree of interlace to enable efficient wind-up of feed yarns at wind-up 10 and removal of the feed yarns from the bobbin for
• a suitable level of interlace for this purpose measured by the rapid pin count (RPC) method, is an RPC interlace of not more than about 14. While
• interlace can be increased such as by employing a
• preferred feed yarns should be high enough to obtain the desired amount of interlace after the drawing extends the distance between the interlace nodes.
• the precise amount of interlace for this purpose will generally depend on the yarn filament count and dpf, the type of yarn finish, and the draw ratio and draw tension experienced by the yarn, and on properties desirable in the final fabric containing the drawn yarns, especially for aesthetic purposes.
• an RPC interlace of between about 6 and about 10.
• the feed yarns are assembled into a warp after spinning.
• the feed yarns undergo dry drawing and dry relaxing to provide drawn yarns, preferably as a warp of feed yarns being treated simultaneously.
• "Dry” drawing and “dry” relaxing as used in this application is intended to indicate that the drawing and relaxation is done in a gaseous environment without the application of liquid water to the yarns.
• the preferred atmosphere for dry drawing and dry relaxing in accordance with the invention is an inert gaseous
• atmosphere such as air having a relative humidity between 50 and 90%, preferably between 60 and 80%.
• the dry drawing and dry relaxing can be done in the presence of other inert gases such as steam which can provide a source of heat as well as an inert atmosphere.
• the yarns are drawn at a draw ratio (DR) of between about 1.05 and about (RDR) r /1.25.
• "Draw ratio" (DR) in this application can be calculated from the “total draw ratio” (TDR) which is defined to be the ratio of the residual draw ratio of the feed yarns (RDR) F to the residual draw ratio of the drawn yarns (RDR) D produced by the process, i.e., after they undergo relaxation:
• TDR total draw ratio
• DR draw ratio
• the draw ratio (DR) may also be calculated from the length change which the yarn is subjected to, e.g., the ratio of the speeds of draw rolls to feed rolls, respectively.
• the total draw ratio (TDR) may be calculated from the speed of the rolls after relaxation to the feed rolls, respectively.
• the temperature of the yarn (T D ) during drawing is between about 20°C and about the temperature T II,** of the polymer.
• T II,** is a temperature of the nylon polymer defined by measuring the change in length of the yarn versus temperature at constant tension. Heating during the dry drawing can be advantageous to decrease the draw tension in the process of the invention.
• the temperature of the yarn during drawing is most preferably less than about T II,L .
• the temperature of drawing can be up to about 175°C.
• the temperature is between about 20° and about 135°C, most preferably, between about 20°C and about 90°C.
• yarn draw temperature should generally be about 20-40°C less than corresponding temperatures for nylon 66.
• Non-contact or contact heating apparatus such as ovens, radiant heaters, plate heaters, hot rolls, microwave heaters and the like are suitable for heating the yarn during drawing.
• the yarn is subjected to a heated relaxation step to control boil-off shrinkage and the relaxation also causes the residual draw ratio of the drawn yarns (RDR D ) to increase slightly.
• the draw ratio (DR) in the dry drawing and the conditions in the dry relaxing are
• BOS shrinkage
• RDR residual draw ratio
• the boil-off shrinkage is between about 3 and about 8%
• the residual draw ratio of the drawn yarns (RDR) D is between about 1.25 and about 1.55.
• other yarn properties can be adjusted for desired end use.
• the invention is capable of providing a range of break elongations and other desired properties while maintaining uniformity in the yarn which can yield dyed fabrics with good dye uniformity.
• tenacities of the drawn yarns are above about 2 g/d and can be as high as about 6 g/d or higher.
• Preferred modulus levels are above about 15 g/d and can range up to about 40 g/d or higher.
• the % overfeed in the relaxation step of the process i.e., the amount of length change allowed to occur through shrinking, must be selected to obtain the properties desired.
• the % overfeed can be set by
• the overfeed can be very small and ranges up to about 10%.
• the % overfeed is between about 2 and about 8%. While the % overfeed can vary within these ranges, the % overfeed should not be too high for the particular feed yarn and relaxation temperature or the tension on the yarns in the relaxation step will drop to zero and the process will not run.
• the appropriate control of overfeed is also
• the overfeed should be adjusted to give a relaxation zone tension of 0.25 to 0.50 grams/drawn denier (g/dd) or preferably 0.30 to 0.375 g/dd. At relaxation zone tension below ⁇ 0.25 g/dd, operability with the tanglereed is poor.
• the temperature of the yarns during relaxation (T R ) must be between about 20°C and a temperature about 40°C less than the melting point of the nylon polymer (T M ).
• non-contact or contact heating apparatus such as ovens, radiant heaters, plate heaters, hot rolls, microwave heaters, and the like are suitable for heating the yarn during relaxation.
• the relaxation temperature (T R ) is selected in accordance with following relationship:
• T M , T II,L , T II,** and T II, * are determined on feeds yarns of the nylon polymer being employed as illustrated in Figure 7 and accompanying text and in the Test Methods which follow.
• a preferred relaxation temperature range for a given residual draw ratio of the drawn yarns (RDR) D may be obtained by
• Preferred relaxation temperatures are less than about 175°C and, most preferably, less than about 135°C for nylon 66 or nylon 66 with a minor amount of a hydrogen bonding constituent.
• nylon 6 a
• preferred temperature range may be defined by assigning the values of 5.35 to K 1 and 1.95 to K 2 , respectively.
• the preferred temperatures for nylon 6 yarns are 20-40°C less than corresponding temperatures for 66 nylon.
• a warp sheet of feed yarn (indicated by the character W) is pulled by feed rolls 11-13 from a creel (not shown) on the left.
• Feed roll 13 is heatable and is usually heated to a temperature of between about 50 and about 90°C.
• An inclined plate heater is provided in this unit and can be used to further heat the yarns if desired.
• the warp of yarn W is then advanced to unheated draw rolls 14-17.
• the draw rolls 14 and 15-17 are driven at a greater speed than the feed rolls to impart the desired amount of draw to the warp of yarns.
• the yarns undergo relaxation as they pass in a warp in contact with a plate heater which has the capability, for this particular warp draw model, to be heated up to about 200°C.
• the amount of relaxation is controlled by exit rolls 18-20 which are driven at a speed appropriately less than that of the draw rolls 14-17 to provide the desired overfeed.
• resulting yarns are wound up simultaneously as a beam at a beam winder (not shown).
• Yarns produced in accordance with the invention have properties which make them extremely well-suited for critical dye application.
• a number of physical properties of the yarns are responsible for the uniform dyability and any one or more of which are very important to the
• Two properties which are believed to be characterisric of the process and the yarns produced by the process of the invention are an along-end %CV of less than about 0.7 by denier variation analysis (DVA) for both the feed and drawn yarns and an along-end %CV of draw tension of less than about 1.0 when drawn 1.33X (DT 33% ) for the feed yarn.
• DVA denier variation analysis
• the preferred method in accordance with the invention provides yarns which have a "large molecule dye uniformity rating" (LMDR) of at least about 6.
• LMDR large molecule dye uniformity rating
• large molecule dye refers to either Anthraquinone
• Milling Blue BL C.I. Acid Blue 122
• Sandolin Milling Blue BL-N C.I. Acid Blue 80
• LMDR Large molecule dye uniformity rating
• LMDR Large molecule dye uniformity rating
• a rating of 5 or below is considered unacceptable and a rating of 5 to 6 is considered borderline acceptable for some non-critical warp knit fabrics.
• a rating of 6 or more is considered acceptable for most warp knit fabrics.
• a rating of 6.5 or more is considered acceptable for critical warp knit fabrics such as those used for swimwear and it is more preferred for yarns in accordance with the present
• Figures 4A and 4B are representative plots of percent change in length ( ⁇ length, %) of a nylon feed yarn versus temperature obtained using a Dupont Thermal Mechanical Analyzer (TMA) at a constant heating rate of 50°C per minute (+ 0.1°C) and varying the pre-tension (also referred herein as stress, ⁇ , expressed as miligrams per original denier) from 3 mg/denier to 500
• TMA Dupont Thermal Mechanical Analyzer
• shrinkage increases with temperature and does not exhibit any spontaneous extension after initial shrinkage between about 40°C and 135°C).
• FIG 5 is a representative plot of the TMA dynamic extension rate, ( ⁇ L/ ⁇ T), versus temperature for a nylon feed yarn under tensions of 50 to 500 mg/d (refer to Figure 4 for details).
• the maximum dynamic extension rate, ( ⁇ L/ ⁇ T)max is taken, herein, as the onset of major crystallization and occurs at temperature T II, * .
• the preferred draw temperature (T D ) is less than about T IIf* .
• Figure 6 is a representative plot of the maximum TMA dynamic extension rates, ( ⁇ L/ ⁇ T) max , versus initial stress, expressed as miligrams per original denier;
• the ( ⁇ L/ ⁇ T) max increases with increasing stress ( ⁇ ) as characterized by a positive slope, d( ⁇ L/ ⁇ T) max /d ⁇ .
• the value of d( ⁇ L/ ⁇ T) max /d ⁇ decreases (Line E to Line A) in general with increasing polymer RV, and increasing spin speed (i.e., decreasing (RDR) s .
• Preferred feed yarns used in this invention are characterized by ( ⁇ L/ ⁇ T) max values less than about 0.20, preferably between about 0.15 and about 0.05 %/°C, and d( ⁇ L/ ⁇ T) max /d ⁇ values, between about 3 ⁇ 10 -4 and about 7 ⁇ 10 -4 (%/°C)/(mg/d) at a stress ( ⁇ ) of 300 mg/d which is selected to characterize the
• Figure 7 is a typical plot of the percent change in length ( ⁇ Length, %) of a nylon feed yarn versus temperature (°C) obtained using a Du Pont Thermal Mechanical Analyser at a constant heating rate of 50°C per minute (+/-0.1°C) under constant tension of 300 miligrams per original denier.
• the onset of extension i.e., ⁇ L > 0
• Tg glass transition temperature
• T II,L which is believed to be related to the temperature at which the hydrogen bonds begin to break permitting extension of the polymer chains and movement of the crystal lamellae.
• Figure 7 is a plot of the corresponding TMA dynamic extension rate to line A, herein defined by the instantaneous change in length per degree centigrade,
• the dynamic extension rate, ( ⁇ L/ ⁇ T) is relatively constant between Tg and the T II,L , and then rises to an initial maximum value at a temperature T II,* , which is believed to be associated with the onset of major crystallization.
• the dynamic extension rate remains essentially constant at the higher level over the temperature range T II, * to T II,U and then rises sharply at T II,U which is associated with the onset of crystal melting and softening of the yarn, until the yarn breaks under tension at a temperature typically less than the melting point (T.); wherein, T II,U is 40°C less than T m .
• T II,** which for nylon 66 polyamides is frequently referred to as the Brill temperature and is associated with the transformation of the less thermally stable Beta-crystalline conformation to the thermally more stable Alpha-crystalline
• the preferred draw conditions for critical acid dyeability have been found to relate to the careful balancing of the extent of drawing (as given by DR), the draw temperature (T D ), the relaxation temperature (T R ), and the extent of relaxation permitted (as given by % overfeed, %OF, or by the extent of relaxation, 1-%OF/100).
• the preferred ranges are: DR between about 1.05X and (RDR) F /1.25; T D of 20°C to less than about T II,** , preferably less than about T II, * and especially less than about T II,L ; T R less than about T II,U (i.e., T M -40°C), preferably less than about T II,** , and especially less than about T II, * .
• T DYC dye transition temperature
• T E " ma x temperature at the maximum dynamic modulus
• Figure 8 is a representative plot of the
• crystallization proceeds via nucleation and continues via growth of the existing crystals between T c and T 2 , .
• the preferred relaxation temperature in draw is less than about T c , i.e., under conditions of uniform nucleation versus crystal growth, especially as the (RDR) D of the drawn yarn is reduced.
• Figure 9 is a graphical representation of the reciprocal of the relaxation temperature (T R , °C), as given by the 1000/(T R + 273), versus the residual draw ratio of the drawn yarns (RDR) D .
• the regions I (ABDE) and II (AEHI) enclosed by heavy lines illustrate temperature conditions in the relaxation step (T R ) as related to the drawing step (RDR D ) of the process useful to produce yarns with excellent large molecule dye uniformity ratings
• Line BCD corresponds to room temperature (RT)
• line AME corresponds to T II,L (about 90°C)
• line KLF corresponds to T II,* (about 135°C)
• line JG corresponds to ⁇ II(** (about 175°C)
• line IH corresponds to T IIf ⁇
• T M melting points (T M ), such as nylon 6 with a melting point about 40°C lower than that of nylon 66 homopolymer, the values of T II,L and T II,** are typically lower giving different values for K 1 and K 2 (see Figure 18 for
• Figures 10 thru 13 are representative thermal responses of nylon feed yarns showing similar thermal transitions as in Figure 6.
• Figure 10 (Line A) is a plot of dynamic shrinkage tension (ST), under constant length conditions at a heating rate of 30°C per minute versus temperature, which increases sharply at temperature Tg and reaches at maximum value at T STmax and then decreases sharply to a temperature, here denoted as T II,L and continues to decrease less sharply between T II ,L and a temperature, here denoted as T II,** and then decreases more rapidly thereafter.
• STmax dynamic shrinkage tension
• FIG. 10 is the corresponding derivative, d(ST)/d(T), of the dynamic shrinkage tension (ST) versus temperature (T) plot (Line A).
• the derivative plot (B) exhibits minimum values which correspond approximately with T II ,L and
• Figure 11 is a typical plot of shrinkage
• Figure 12 is a typical plot of the logarithm of the dynamic modulus (E'), Line A, and of the
• Figure 13 is a typical plot of the change in heat flow versus temperature as measured by Differential Scanning Calorimetry (DSC).
• DSC Differential Scanning Calorimetry
• An inset enlargement of temperature range of 60°C to 200°C shows three thermal transitions attributed to T II,L , T II,* , and T II,** , respectively.
• the onset of the melting endotherm at about 225°C for this nylon 66 yarn is associated with T II,U and is about 40°C less than the melting point T M .
• Figures 14 and 15 are typical plots of the TMA dynamic extension rates at 300 mg/d pre-tension versus temperature for the warp drawn yarns of Examples IV-3 and IV-10, respectively; wherein the yarns of Ex. IV-10 have a LMDR > 6 and the yarns of Ex. IV-3 have a LMDR of less than 6 which corresponds to the greater variability of ( ⁇ L/ ⁇ T) versus temperature between temperatures A and D, especially between A and C (compare Figure
• Figure 16 (line A) is a representative plot of the
• stabilization is usually required to provide a stable yarn package. Below about 4000 mpm, the as-spun yarn must be further stabilized to provide a useful yarn package for warp drawing (see discussion of Figure 1).
• Figure 17 (line A) is a representative plot of the length change after boil-off of spun yarns not
• Yarns used in this invention are of regions II and III and preferably of region III for it is observed that yarns of region III have very little sensitivity to moisture-on-yarn during finish application on dye level (MBB) and their yarn properties are more stable with time on storage.
• Figure 18 is a representative TMA plot of the dynamic extension rates ( ⁇ L/ ⁇ T) under a 300 mg/d
• Nylon 6 feed yarns are shifted about 20-30°C to lower temperatures versus nylon 66 feed yarns which reduces the maximum relaxation temperature (T R ) MAX for nylon 6 by about 20-30°C versus that for nylon 66 homopolymer.
• Figure 19 is a representative TMA plot of shrinkage ( ⁇ Length, %) versus temperature under a 5 mg/d tension for different yarn types.
• Most feed yarns shrink with increasing temperature especially between 40°C and 135°C; however, Yarn A initially elongates and only shrinks at temperatures above about 150°C.
• Yarn A is not a preferred feed yarn since it does not shrink, but elongates between 40 and 135°C (i.e., ⁇ L > 0); and also since it is characterized by a positive rate of length change, herein referred to as a "positive dynamic
• Preferred feed yarns for draw have a negative dynamic length change and a negative dynamic shrinkage rate over the temperature range of 40°C and 135°C.
• Figure 20 is a representative plot of draw stress ( ⁇ D ) , expressed as a grams per drawn denier, versus draw ratio at 20°C, 75°C, 125°C, and 175°C.
• draw stress ( ⁇ D ) increases linearly with draw ratio above the yield point and the slope is called herein as the draw modulus (M D ) and is defined by ( ⁇ D / ⁇ DR).
• the values of draw stress ( ⁇ D ) and draw modulus (M D ) decrease with increasing draw temperature (T D ).
• the desired level of draw stress ( ⁇ D ) and draw modulus (M D ) can be controlled by selection of feed yarn type and draw temperature (T D ).
• Preferred draw feed yarns have a draw stress ( ⁇ D ) between about 1.0 and about 2.0 g/dd, and a draw modulus (M D ) between about 3 and about 7 g/dd, as measured at 75°C and at a 1.35 draw ratio (DR) taken from a plot of draw stress ( ⁇ D ) versus draw ratio.
• Figure 22 is a representative plot of the logarithm of draw modulus, ln(M D ), versus [1000/(T D , C + 273)] for the three yarns in Figure 21.
• Preferred draw feed yarns have an apparent draw energy (E D ) A
• E D /R ⁇ (lnM D )/ ⁇ (1000/T D ), where T D is in degrees Kelvin] between about 0.2 and 0.6 (g/dd)/°K.
• Figure 23 is a representative plot of percent dye exhaustion (%E), for C.I. Acid Blue 122, versus dye temperature (°C) with an increase in dye exhaustion occurring at about 57-58°C which corresponds to the dye bath temperature to reach about 15% exhaustion herein defined herein as the dye transition temperature, T DYE .
• Figure 23 (Line B) is a corresponding plot of Line A expressed as percent exhaustion on a logarithmic scale versus the reciprocal of the dye bath temperature
• T DYE dye transition temperature
• T (°C) temperature at 15% dyebath exhaustion (using C.I. Acid Blue 122).
• Figure 24 is a representative plot of dye bath exhaustion curves (C.I. Acid Blue 122) versus
• Figure 25 is a representative plot of measured dye rate (S 25 ) at 25°C using a large molecule acid dye, C.I. Acid Blue 40, versus the residual elongation of warp drawn yarns made from different feed yarns; where Line A is from a feed yarn spun greater than about 4000 mpm
• Line B is from a feed yarn spun between about 2500 and 4000 mpm (region II in Figs. 16 and 17)
• Line C is from a feed yarn spun less than 2000 mpm (region I in Figs. 16 and 17).
• the dye rate at a given residual elongation is observed to increase with the spin speed of the feed yarn used in the dry draw/dry relax warp draw process.
• Drawn yarns from feed yarn C are nonuniform at all drawing and relaxation process
• Figure 26 is a plot of the Apparent Pore
• ACM Apparent Pore Volume
• Drawn yarns providing a LMDR of at least about 6 are found to have a combination of an APM greater than about 2 (Line CC'E) and greater than about (4.75-0.37 ⁇ 10 -4 APV), Line ABCD; and an APV greater than 4 ⁇ 10 -4 cubic angstroms (Line BB'G).
• Preferred yarns have an APM greater than 2 and greater than (5-0.37 ⁇ 10 - 4 APV), ⁇ .ine A'B'C'D; and an APV greater than 4 ⁇ 10 -4 cubic angstroms.
• Yarns having combinations of APM and APV, corresponding to region BGFEC are also characterized by a dye transition temperature T DYE less than about 65°C.
• the Relative Viscosity (RV) of the polyamide is measured as described at col. 2, 1. 42-51, in Jennings U.S. Patent No. 4,702,875.
• Denier of the yarn is measured according to ASTM Designation D-1907-80. Denier may be measured by means of automatic cut-and-weigh apparatus such as that described by Goodrich et al in U.S. Patent No. 4,084,434.
• Modul ⁇ s (M), often referred to as "Initial Modulus,” is obtained from the slope of the first reasonably straight portion of a load-elongation curve, plotting tension on the y-axis against elongation on the x-axis.
• the Secant Modulus at 5% Extension (M5) is defined by the ratio of the (Tenacity / .05) X 100, wherein Tenacity is measured at 5% extension.
• Yarn Temperature is measured by a noncontact method using an infrared microscope using the procedure described by Zieminski and Spruiell, J. Appl. Polymer Science, 35, 2223,2245(1988) and Bheda and Spruiell, J. Appl. Polymer Science 39,447-463(1990). Temperature of equipment described herein, e.g., rolls, etc. is measured with standard thermocouples.
• Boil-off shrinkage (BOS). The following relaxed skein method is used for the feed yarns described in this application and measures the change in length as a percentage of the original length of a skein of yarn upon immersion in boiling water. Skeins of yarn are prepared on a standard denier reel of 1-1/8 meters in
• the number of revolutions of the reel is determined from the weight used to measure the skein length.
• the weight should be as follows:
• the number of revolutions is that required to give a load of 55 mg/denier and is calculated from the following formula:
• Boil-Off Shrinkage The following loop method is used for the measurement of boil-off shrinkage of the warp drawn yarns.
• the yarn is tied in a loop having a length of about 50 cm and the length of the loop is measured under a load of 0.05 g/d using a meter stick.
• the load is removed and the loop is placed in boiling water with a load of about 0.6 g to prevent it floating and becoming entangled in the water.
• the loop is dried in air and the length is remeasured under a load of 0.05 g/d.
• Boil-off shrinkage is calculated as follows:
• Heat Set Shrinkage After Boil Off (HSS/ABO) is measured by immersing a skein of the test yarn into boiling water and then placing it in a hot oven and measuring shrinkage. More specifically, a 500 gram weight is suspended from a 3000 denier skein of the test yarn (6000 denier loop) so that the force on the yarn is 83 mg./denier, and the skein length is measured (Ll). The 500 gm. weight is then replaced with a 30 gm. weight and the weighted skein is immersed into boiling water for 20 minutes removed and allowed to air dry for 20 minutes.
• Heat set shrinkage after boil-off is typically greater than BOS, that is, the yarns continue to shrink on DHS at 175°C ABO which is preferred to achieve uniform dyeing and finishing.
• DHS90 and DHS1375 are measured by the method described in U.S. Patent No. 4,134,882, Col. 11, 11. 42-45 except that the oven
• temperatures are 90 degrees C, 135 degrees C, and 175 degrees C, respectively, instead of 160 degrees C.
• LMDR Large Molecule Acid Dye Uniformity
• the bath is run for 5 minutes, and the bath temperature is then raised to 212°at 3°F/min. After running the bath for 60 minutes, the pH is measured. If the pH is >5.7, it is adjusted to 5.5 and run another 30 minutes. The bath is then cooled to 170°F, emptied, and cleared with clear water. Fabric is removed from the bath and dried.
• the yarns in the fabrics were evaluated for LMDR as follows:
• Fabric swatches full width, i.e., approx-mately 60 inches wide and about 20-60 inches long
• the fabric is rated by a panel of experts (the ratings of 5 to 7 experts are
• the selected ratings on the rating scale is:
• each sample weighing 1 gram is prepared, preferably by jetting the yarn onto small dishes. 9 samples are for control; the remainder are for test.
• Anthraquinone Milling Blue BL (abbreviated MBB) (C.I. Acid Blue 122).
• MBB Anthraquinone Milling Blue BL
• Acid Blue 122 C.I. Acid Blue 122
• the final bath pH is 5.1.
• T D ⁇ E diode transition temperature, which is that temperature at which there is a sharp increase in dye uptake rate
• the dyed samples are rinsed, dried, and measured for dye depth by reflecting colorimeter.
• the dye values are determined by computing K/S values from reflectance readings. The equations are:
• R the reflectance value.
• the 180 value is used to adjust and normalize the control sample dyeability to a known base.
• a set of samples is prepared in the same manner as for MBB Dyeability. All samples are then dyed by immersing them into 54 liters of an aqueous dye solution comprised of 140 ml. of a standard buffer solution, 100 ml of 10% Merpol LFH (a liquid, nonionic detergent from E. I. du Pont de Nemours and Co.), and 80-500 ml of 0.56%
• an aqueous dye solution comprised of 140 ml. of a standard buffer solution, 100 ml of 10% Merpol LFH (a liquid, nonionic detergent from E. I. du Pont de Nemours and Co.), and 80-500 ml of 0.56%
• ALIZARINE CYANINE BLUE SAP (abbreviated ABB) (C.I. Acid Blue 45).
• the final bath pH is 5.9.
• the dye values are determined by computing K/S values from reflectance readings.
• the equations are:
• % CV of K/S measured on fabrics provides an indication of LMDR. High LMDR corresponds to low K/S values. Low % CV of K/S values is desirable.
• Dye Transition Temperature is that temperature during dyeing at which the fiber structure opens up sufficiently to allow a sudden increase in the rate of dye uptake. It is related to the polymer glass transition temperature, to the thermomechanical history of the fiber, and to the size and configuration of the dye molecule.
• the dye transition temperature may be determined for C.I. acid blue 122 dye as follows: Prescour yarn in a bath containing 800 g of bath per g of yarn sample. Add 0.5 g/1 of tetrasodium pyrophosphate (TSPP) and 0.5 g/1 of Merpol (R) HCS. Raise bath temperature at a rate of
• the dye transition temperature is a measure of the openness of the fiber structure and preferred values of T DYE for warp drawn yarns are less than about 65°C, especially less than about 60°C
• the denier variation analyzer is a capacitance instrument, using the same principle as the Uster, for measuring along-end denier variation.
• the DVA measures the change in denier every 1/2 meter over a 240 meter sample length and reports %CV of these measurements. It also reports % denier spread, which is the average of the high minus low readings for eight 30 meter samples. Measurements in tables using the DVA are reported as coefficient of variation (DVA %CV) .
• a static tension corresponding with 0.1 grams per denier (based on pre-test denier) is used.
• a heating rate of 1.4 ⁇ 0.1 degrees C/minute is used and the test frequency is 110 Hz.
• the computerization equipment makes one reading approximately every 1.5 minutes, but this is not constant because of variable time required for the computer to maintain the static tension constant by adjustment of specimen length.
• the initial specimen length is 2.0 ⁇ 0.1 cm.
• the test is run over the temperature range -30 to 230 degrees C Specimen denier is adjusted to 400 ⁇ 30 by plying or dividing the yarn to assure that dynamic and static forces are in the middle of the load cell range.
• the position (i.e., temperature) of tan delta and E" peaks is determined by the following method. First the approximate position of a peak is estimated from a plot of the appropriate parameter vs. temperature. The final position of the peak is determined by least squares fitting a second order polynomial over a range of ⁇ 10-15 degrees with respect to this estimated position
• transition temperatures i.e., the temperature of inflection points are determined similarly. The approximate inflection point is estimated from a plot. Then sufficient data points to cover the transition from one apparent plateau to the other are fitted to a third order polynomial considering temperature to be the independent variable.
• T E-max The E" peak temperature (T E-max ) around 100°C (see Figure 12) is taken as the indicator of the alpha transition temperature (T A ) and it is important to have this a low value (i.e., less than 100°C,
• DSC Differential Scanning Calorimeter
• DTA Differential Thermal Analyzer
• nylon 66 homopolymer is typically 260-262°C and is lowered by about 1°C/1% by weight of copolyadipamides, such as by addition of N6 and Me-5,6.
• the melting point of nylon 6 homopolymer is typically 222°C (i.e., about 40°C lower than nylon 66) and may be raised by addition of higher melting point
• copolyamides such as by addition of N66.
• Tables, herein) in 6-6 nylon is determined as follows: A weighed nylon sample is hydrolyzed (by refluxing in 6N HCI), then 4-aminobutyric acid is added as an internal standard. The sample is dried and the carboxylic acid ends are methylated (with anhydrous methanolic 3N HCI), and the amine ends are trifluoroacylated with
• 6-aminocaproic acid peak to the derivatized 4-aminobutyric acid peak is converted to mg 6 nylon by a calibration curve, and wt. % 6 nylon is then calculated.
• Me5-6 in weight percent (reported as MPMD % in the Tables) is determined by heating two grams of the polymer in flake, film, fiber, or other form (surface materials such as finishes being removed) at 100°C overnight in a solution containing 20 mis of
• the diamines elute from the column in about 5 minutes, the MPMD eluting first.
• the weight percentage MPMD is calculated from the ratio of the integrated areas under the peaks for the MPMD and HMD and the weight percent Me5-6 is calculated from the weight percentage of the MPMD.
• Draw Tension (DT 33% ), expressed as grams per original denier, is measured while drawing the yarn to be tested while heating it. This is most conveniently done by passing the yarn from a set of nip rolls, rotating at approximately 180 meters/minute surface speed, through a cylindrical hot tube, at 185 + 2°C (characteristic of the exit gain temperature in high speed texturing), having a 1.3 cm diameter, 1 meter long yarn passageway, then to a second set of nip rolls, which rotate faster than the first set so that the yarn is drawn between the sets of nip rolls at a draw ratio of 1.33 X.
• a conventional tensiometer placed between the hot tube and the first set of nip rolls measures, yarn tension. The coefficient of variation is determined statistically from replicate readings.
• Draw Tension @ 1.00 Draw Ratio (herein referred to as “along-end shrinkage tension”) is measured in the same manner as DT 5% except that the draw ratio is 1.00X and the hot tube temperature is 75°C.
• the Dynamic Shrinkage Tension (ST) is measured using the Kanebo Stress Tester, model KE-2L, made by
• the Dynamic Length Change ( ⁇ L) of a yarn under a pretensioning load versus increasing temperature ( ⁇ T) is measured using the Du Pont Thermomechanical Analyzer
• centigrade is measured on a 12.5 milimeter length of yarn which is: 1) mounted carefully between two press-fit aluminum balls while keeping all individual filaments straight and unstressed with the cut filament ends fused outside of the ball mounts using a micro soldering device to avoid slippage of individual filaments; 2) pre-stressed to an initial load of 5 mg/denier for measurement of shrinkage and to 300 mg/denier for measurement of
• Preferred draw feed yarns have a negative length change (i.e, the yarns shrink) under a 5 mg/d tension over the temperature range of 40°C to 135°C
• Preferred draw feed yarns have a negative dynamic shrinkage rate (i.e., the yarns do not elongate after initially shrinking) over the temperature range on 40°C to 135°C
• a negative dynamic shrinkage rate i.e., the yarns do not elongate after initially shrinking
• the value of ( ⁇ L/ ⁇ T) is found to increase with increasing temperature, reaching an
• Preferred draw feed yarns have a ( ⁇ L/ ⁇ T)max value, as measured at 300 mg/d, of less than about 0.2 (%/°C), preferably less than about 0.15 (%/°C) and greater than about 0.05 %/°C
• Another important characteristic of a polymer network is the sensitivity of its ( ⁇ L/ ⁇ T)max value with increasing stress which is defined as the tangent to the plot of ( ⁇ L/ ⁇ T)max versus ⁇ D at a ⁇ D -value of 300 mg/d (denoted by d( ⁇ L/ ⁇ T) MAX /d ⁇ D ) and determined on separate specimens pre-stressed from 3 mg/d to 500 mg/d (see figures 5 and 6).
• a 300 mg/d stress value is selected for characterization since it approximates the nominal stress level in the draw relaxation zone (i.e., between rolls 17 and 18 in Figure 2).
• the Hot Draw Stress ( ⁇ D ) vs. Draw Ratio Curve is used to simulate the response of a draw feed yarn to increasing draw ratio (DR) and draw temperature (T D ).
• the draw stress ( ⁇ D ) is measured the same as DT 33 %, except that the yarn speed is reduced to 50 meters per minute, the measurement is taken over a length of 100 meters, and different temperatures and draw ratios are used as
• the draw stress ( ⁇ D ) increases linearly with draw ratio for values of DR greater than about 1.05 (i.e., above the yield point) to the onset of strain-hardening (i.e., to a residual draw ratio (RDR) D of about 1.25), and the slope of best fit linear plot of draw stress versus draw ratio is herein called the draw modulus (M D - ⁇ D / ⁇ DR).
• draw stress ( C ⁇ ) and draw modulus (M D ) decrease with increasing draw temperature (T D ).
• the desired level of draw stress ( ⁇ D ) and draw modulus (M D ) can be controlled by selection of feed yarn type and draw temperature (T D ).
• Preferred draw feed yarns have a draw stress ( ⁇ D ) between about 1.0 and about 2.0 g/dd, and a draw modulus (M D ) between about 3 to about 7 g/dd, as measured at 75°C and at a 1.35 draw ratio (DR) taken from a best fit linear plot of draw stress ( ⁇ D ) versus draw ratio (see Figures 20 and 21).
• T g temperature, before the network has been modified by thermal recrystallization
• E D Apparent Draw Energy a , is the rate of decrease of the draw modulus with increasing temperature (75°C, 125°C, 175°C) and is defined as the slope of a plot of the logarithm of the draw modulus, ln(M D ), versus
• the Differential Dye Variance is a measure of the along-end dye uniformity of a warp drawn yarn and is defined by the difference in the variance of K/S measured in the axial and radial directions, respectively, on a lawson knit sock dyed according to the MBB dye procedures described herein.
• the LMDR of a warp knit fabric is found to vary inversely with the warp drawn yarn Differential Dye Variance (axial K/S variance - radial K/S variance).
• the warp draw process of the invention balances the draw temperature, extent of draw, relaxation temperature, and extent of relaxation so to minimize the Differential Dye Variance (DDV) of the warp drawn yarn product.
• Tensions expressed in terms of grams per drawn denier (g/dd) may be measured by use of the Rothschild Electronic
• Typical nylon 66 polymer has about 30-50 equivalents of NH2-ends and "deep" dye nylon 66 polymer has about 50-70 equivalents of NH2-ends.
• the number average molecular weight (M H ) is approximately proportional to the
• Density( p) of the polyamide fiber is measured by use of the standard density gradient column technique using carbon tetrachloride and heptane liquids at 25°C
• the Fractional Volume Crystallinity (Xv) is calculated from the fiber density (p) measurement using the following formula: X v - (p-p a )/(p c -p a ); where, p c is the density of the perfectly crystalline phase and p a is the density of the amorphous phase.
• p c 1.22 g/cm 3
• p a 1.069 g/cm 3 [H. W. Starkweather, Jr., R. E. Moynihan, Journal of Polymer Science, vol. 22, p. 363 (1956)].
• Fractional Weight Crystallinity (Xw) and the fractional volume crystallinity (Xv) are related by the formula: Xw - Xv (p/p c ).
• the fractional volume crystallinity varies only slightly with warp draw process conditions, e.g., typically varying from about 0.5 to about 0.55.
• the Optical Parameters of the fibers are
• the average value of any of the optical parameters is defined as the average of the two values at +.05, e.g.:
• ⁇ RISO> ( RISO( .05 ) + RISO( - .05 ) )/2 , and similarly for the Average Birefringence ( ⁇ n).
• the average birefringence ( ⁇ n) may in turn be expressed as the sum of the crystalline ( ⁇ c) and amorphous ( ⁇ a)
• Crystal Perfection Index (CPI) and Apparent Crystallite Size Crystal perfection index and apparent crystallite size are derived from X-ray diffraction scans. The diffraction pattern of fibers of these compositions is characterized by two prominent equatorial X-ray
• X-ray diffraction patterns of these fibers are obtained with an X-ray diffractometer (Philips Electronic Instruments, Mahwah, N.J., cat. no. PW1075/00) in
• Pulse Height Analyzer "Differential"
• the diffraction data are processed by a computer program that smoothes the data, determines the baseline, and measures peak locations and heights.
• Crystal Perfection Index (CPI) (as taught by P. F. Dismore and w. O. Statton, J. Polym. Sci. Part C, No. 13, pp. 133-148, 1966).
• CPI Crystal Perfection Index
• the positions of the two peaks at 21° and 23° 26 are observed to shift, and as the crystallinity increases, the peaks shift farther apart and approach the positions corresponding to the "ideal" positions based on the Bunn-Garner 66 nylon structure. This shift in peak location provides the basis of the measurement of Crystal Perfection Index in 66 nylon:
• d(outer) and d(inner) are the Bragg 'd' spacings for the peaks at 23° and 21° respectively, and the denominator 0.189 is the value for d(100)/d(010) for well-crystallized 66 nylon as reported by Bunn and Garner (Proc. Roya]
• Apparent Crystallite Size is calculated from measurements of the half-height peak width of the equatorial diffraction peaks. Because the two equatorial peaks overlap, the measurement of the half-height peak width is based on the half-width at half-height. For the 20°-21° peak, the position of the half-maximum peak height is calculated and the 26 value for this intensity is measured on the low angle side. The difference between this 26 value and the 26 value at maximum peak height is multiplied by two to give the half-height peak (or "line”) width.
• the position of the half-maximum peak height is calculated and the 26 value for this intensity is measured on the high angle side; the difference between this 26 value and the 26 value at maximum peak height is multiplied by two to give the half-height peak width.
• 'b' is the instrumental broadening constant. 'b' is determined by measuring the line width of the peak located at approximately 28° 2 ⁇ in the diffraction pattern of a silicon crystal powder sample.
• ⁇ is the X-ray wavelength (here 1.5418A);
• ACS is the corrected line breadth in radians; and ⁇ is half the Bragg angle (half of the 26 value of the selected peak, as obtained from the diffraction pattern).
• the ACS for the "outer” and “inner” d-spacings are also referred to as ACS(IOO) and ACS(OIO), respectively.
• An Apparent Crystallite Volume (ACV) is herein defined by the expression: ACV - [ACS(100)*ACS( 010)] 3/2 , ⁇ 3 .
• X-ray Orientation Angle A bundle of filaments about 0.5 mm in diameter is wrapped on a sample holder with care to keep the filaments essentially parallel. The filaments in the filled sample holder are exposed to an x-ray beam produced by a Philips x-ray generator (Model 12045B) available from Philips Electronic Instruments. The diffraction pattern from the sample filaments is recorded on Kodak DEF Diagnostic Direct Exposure X-ray film (Catalogue Number 154-2463), in a Warhus pinhole camera. Collimators in the camera are 0.64 mm in
• the exposure is continued for about fifteen to thirty minutes (or generally long enough so that the diffraction feature to be measured is recorded at an
• Transmitted intensities are calibrated using black and white references, and gray level (0-255) is converted into optical density.
• the diffraction pattern of 66 nylon, 6 nylon, and copolymers of 66 and 6 nylon has two prominent equatorial reflections at 26 approximately 20°-21° and 23°; the outer (-23°) reflection is used for the
• Orientation Angle A data array equivalent to an azimuthal trace through the two selected equatorial peaks (i.e. the outer reflection on each side of the pattern) is created by interpolation from the digital image data file; the array is constructed so that one data point equals one-third of one degree in arc.
• the Orientation Angle (OA) is taken to be the arc length in degrees at the half-maximum optical density (angle subtending points of 50 percent of maximum density) of the equatorial peaks, corrected for back-ground. This is computed from the number of data points between the half-height points on each side of the peak (with
• LPS long period spacing
• LPI long period intensity
• the diffractometer is installed at a line-focus port of a Philips XRG3100 x-ray generator equipped with a long fine focus X-ray tube operated at 45KV and 40ma.
• the X-ray focal spot is viewed at a 6 degree take-off angle and the beam width is defined with a 120 micrometer entrance slit.
• the copper K-alpha radiation from the X-ray tube is filtered with a 0.7 mil nickel filter and is detected with a Na ⁇ (TI) Scintillation counter equipped with a pulse height analyzer set to pass 90% of the
• the nylon samples are prepared by winding the fibers parallel to each other about a holder containing a 2 cm diameter hole.
• the area covered by the fibers is about 2 cm by 2.5 cm and a typical sample contains about 1 gram of nylon.
• the actual amount of sample is determined by measuring the attenuation by the sample of a strong CuK-alpha x-ray signal and adjusting the thickness of the sample until the transmission of the X-ray beam is near 1/e or .3678.
• a strong scatterer is put in the diffracting position and the nylon sample is inserted in front of it, immediately beyond the beam defining slits. If the measured intensity without attenuation is Io and the attenuated intensity is I, then the transmission T is I/(Io).
• transmission of 1/e has an optimum thickness since the diffracted intensity from a sample of greater or less thickness than optimum will be less than that from a sample of optimum thickness.
• the nylon sample is mounted such that the fiber axis is perpendicular to the beam length (or parallel to the direction of travel of the detector).
• the fiber axis is perpendicular to the table top.
• a scan of 180 points is collected between 0.1 and 4.0 degrees 26, as follows: 81 points with step size 0.0125 degrees between 0.1 and 1.1 degrees; 80 points with step size 0.025 degrees between 1.1 and 3.1 degrees; 19 points with step size 0.05 degrees between 3.1 and 4.0 degrees.
• the time for each scan is 1 hour and the counting time for each point is 20 seconds.
• the resulting data are smoothed with a moving parabolic window and the instrumental background is subtracted.
• the instrumental background i.e. the scan obtained in the absence of a sample, is multiplied by the transmission, T, and subtracted, point by point, from the scan obtained from the sample.
• the data points of the scan are then corrected for sample thickness by
• the measured intensities arise from reflections whose diffraction vectors are parallel to the fiber axis. For most nylon fibers, a reflection is observed in the vicinity of 1 degree 26. To determine the precise
• a background line is first drawn underneath the peak, tangent to the diffraction curve at angles both higher and lower than the peak itself.
• a line parallel to the tangent background line is then drawn tangent to the peak near its apparent maximum but generally at a slightly higher 26 value.
• the 26 value at this point of tangency is taken to be the position since it is position of the maximum if the sample back-ground were subtracted.
• the long period spacing, LPS is calculated from the Bragg Law using the peak position thus derived. For small angles this reduces to:
• the intensity of the peak, LPI is defined as the vertical distance, in counts per second, between the point of tangency of the curve and the background line beneath it.
• the Kratky diffractometer is a single beam instrument and measured intensities are arbitrary until standardized.
• the measured intensities may vary from instrument to instrument and with time for a given
• Sonic Modulus is measured as reported in Pacofsky U.S. Patent No. 3,748,844 at col. 5, lines 17 to 38, the disclosure of which is incorporated by reference except that the fibers are conditioned for 24 hours at 70°F (21 °C) and 65% relative, humidity prior to the test and the nylon fibers are run at a tension of 0.1 grams per denier rather than the 0.5-0.7 reported for the polyester fibers of the referenced patent.
• Preferred drawn yarns have sonic modulus (Ms) values between about 40 and 60 g/d, and especially between about 40 and 55 g/d.
• Cross Polarization combined with "magic angle spinning” are Nuclear Magnetic Resonance (NMR) techniques used to collect spectral data which describe differences between the copolymer and homopolymer in both structure and composition.
• NMR Nuclear Magnetic Resonance
• solid state carbon-13 (C-13) and nitrogen-15(N-15) NMR data obtained using CP/MAS can be used to examine contributions from both crystalline and amorphous phases of the polymer.
• Structural information concerning the amorphous phases of the polymer is obtained by techniques described by Veeman in the above mentioned article and by VanderHart in Macromolecules 12, 1232 (1979) and Macromolecules 18, 1663 (1985).
• C-13 T1 and C-13 Tlrho Parameters governing molecular motion are obtained by a variety of techniques which include C-13 T1 and C-13 Tlrho.
• the C-13 T1 was developed by Torchia and described in J. Magnetic Resonance, vol. 30, 613 (1978).
• the measurement of C-13 Tlrho is described by Schafer in Macromolecules 10, 384 (1977).
• Natural abundance nitrogen-15 NMR is used to provide complementary information in addition to that obtained from carbon-13 solid state NMR analysis. This analysis also provides information on the distribution of crystal structures with the polymer as illustrated by Mathias in Polymer Commun. 29, 192 (1988).
• a 3 dpf round filament with a density of 1.14 g/cm 3 having a measured dye rate of 50 ⁇ 10 -5 sec -1 has a calculated apparent diffusion coefficient (D A ) of 14.6 ⁇ 10 -10 cm 2 sec -1 .
• Preferred filaments have an apparent diffusion coefficient (D A ) of at least about 15 ⁇ 10- 10 cm 2 sec -1 and especially preferred have an apparent diffusion
• D A coefficient (D A of at least about 20 ⁇ 10 -10 cm 2 sec -1 .
• Apparent Pore Mobility and Apparent Pore Volume (APV) are measures of the openness of the amorphous regions to permit sufficient dye uptake for uniform along-end dyeing.
• the drawn yarns preferably have an APM greater than about 2 and greater than about
• Parts A-E illustrate the poor fabric appearance after dying of fabrics knit from nylon flat yarns produced by warp-drawing and relaxing of feed yarns spun at low withdrawal speeds. These yarns, which are unsatisfactory for critical dye applications, are believed to result in poor fabric appearance because of along-end variations in dye uptake which are worse than fully-drawn yarns produced by a conventional spin-draw process.
• Parts F-K illustrate the process of the invention and the superior LMDR values obtainable using yarns produced in accordance with the invention.
• Part A - Comparative Nylon 6 having an RV of ⁇ 46 is spun at a melt temperature of 270°C through a spinneret having 13
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 67 feet per minute (fpm). It is spun using a very low withdrawal speed of 590 mpm and is not mechanically drawn during the spinning process. This yarn can be referred to as a "low
• the resulting 134 denier yarn has a very low orientation making it unsuitable for knitting or weaving as evidenced by a high elongation of about 320%.
• bobbins of the feed yarn are placed on a creel equipped with tensioning devices for use in making yarn for 21" wide tricot.
• the creel and tensioning devices are the same as those commonly used for preparing beams of yarn.
• the ends of yarn are passed through reeds and guides designed to arrange the yarns in a parallel manner to form a warp, and are then passed to a Barmag STF1 draw unit at a warp draw ratio of 3.00, a draw roll temperature of 60°C, an overfeed of 2.5%, a relaxation temperature of 22°C, and wound onto a beam at a speed of 320 mpm.
• the resulting yarn has a denier of 44.2 and an elongation of 52.8%.
• Beams of the drawn yarn are knit into a 32 gauge tricot fabric and dyed with C. I. Acid Blue 80 dye
• the dyed fabric is rated for uniformity and unacceptable LMDR of 4 is achieved. Details of the process and yarn properties are provided in Table 1.
• Nylon 66 having an RV of ⁇ 40 is spun at a melt temperature of 290°C through a spinneret containing 14 capillaries of length 0.022" and diameter 0.015".
• the filaments are quenched and converged as in Part A to produce a 125 denier feed yarn having properties as described in Table I.
• 670 bobbins of the feed yarn are drawn at 500 mpm using a Karl Mayer DSST 50 machine as indicated in Table I to produce a 44 denier yarn with the properties listed in Table I.
• the LMDR is an unacceptable 3.5
• Nylon 6,6 having an RV of "42 is spun at a melt temperature of 290°C through a spinneret having 13
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 67 feet per minute (fpm).
• the filaments are converged into yarn at a finish roll applicator just below the quench cabinet.
• the yarn is then passed through an interfloor tube to a feed roll which provides a withdrawal speed of 1500 mpm and then to a draw roll at a speed 1.60 times that of the feed roll or 2400 mpm. Subsequent rolls may vary the speed slightly from 2400 mpm to adjust tensions. Interlace was applied at a level sufficient for efficient removal of the yarn later from the bobbin.
• the yarn is wound on a tube at a tension of ⁇ 0.2 g/d.
• This yarn having been mechanically drawn only 1.60X, is at this point only partially oriented and does not yet possess the tensile properties ideal for warp knitting or weaving and is used as the feed yarn for the warp draw operation described before. It has a denier of 55 and an elongation of ⁇ 80% and can be referred to as a partially drawn yarn (PDY).
• PDY partially drawn yarn
• the feed yarn is warp drawn on a Barmag model STF1 draw unit at a draw ratio of 1.39X, a draw
• the resulting yarn has a denier of 42 and an elongation of 30%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 122 dye, and rated for LMDR.
• the LMDR is an unacceptable 4.4. Details of the process and yarn properties are provided in Table 1.
• the feed yarn is prepared as described in Part C except that the RV is 44, the feed roll (withdrawal) speed is 1849 mpm, the wind-up speed is 3217 mpm, and the draw ratio is 1.74X.
• the feed yarn in this example is 53 denier/13 filaments, has an elongation of 74% and a draw tension of 58 g.
• the feed yarn is warp drawn on the Karl Mayer DSST 50 unit at a draw ratio of 1.35X, and a draw roll temperature of 70°C
• the drawn yarn is overfed by 5% to the exit rolls, relaxed at 129°C between the draw rolls and the exit rolls, and wound into a beam at 500 mpm.
• the resulting PDY yarn has a denier of 41 and an elongation of ⁇ 40%.
• Beams of the warp drawn yarn are knitted on a 32 gauge tricot knitting machine to form a warp knit fabric.
• the fabric is dyed using C.I. Acid Blue 80 dye and rated for LMDR uniformity.
• An unacceptable LMDR of 3 is
• the feed yarn is prepared as described in Part C except that the RV is 45, the feed roll (withdrawal) speed is 1937 mpm, the wind-up speed is 3254 mpm, and the draw ratio is 1.68X.
• the feed yarn in this example is 95 denier/34 filaments, has an elongation of 67% and other properties as indicated in Table I.
• the feed yarn is warp drawn on the Barmag model STF1 unit at a draw ratio of 1.43X, and a draw roll temperature of 60°C
• the drawn yarn is overfed by 5% to the exit rolls, relaxed at 22°C between the draw rolls and the exit rolls, and wound into a beam 500 mpm.
• the resulting PDY yarn has a denier of 72.7 and an elongation of -34.2%.
• Beams of the warp drawn yarn are knitted on a 32 gauge tricot knitting machine to form a warp knit fabric.
• the fabric is dyed using C.l. Acid Blue 80 dye and rated for LMDR uniformity. An unacceptable LMDR of 3 is
• Nylon 6,6 having an RV of ⁇ 42 is spun at a melt temperature of 290°C through a spinneret containing 17 capillaries of length 0.022" and diameter 0.015".
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 67 fpm.
• the yarn is then passed through an interfloor tube to a feed roll which provides a withdrawal speed of 2818 mpm and then to a draw roll at a speed 1.26 times that of the feed roll or 3551 mpm. Subsequent rolls may vary the speed slightly from 3551 mpm to adjust tensions and apply interlace.
• the yarn is wound on a tube at about 3551 and at a tension of ⁇ 0.2 gpd. The result is a 55 denier PDY yarn with an
• the yarn is warp drawn on the Barmag STF1 draw unit at a draw ratio of 1.29, a draw temperature of 60°C, an overfeed of 6%, was relaxed at 22°C and wound into a beam at a speed of 550 mpm.
• the resulting yarn had a denier of 45.5 and an elongation of 28.5%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 80 dye according to the LMDR procedure, and rated for
• the uniformity rating is an excellent 7.8.
• Nylon 6,6 having an RV of ⁇ 50 is spun at a melt temperature of 290°C through a spinneret containing 17 trilobal capillaries of leg length 0.015" and leg width 0.004".
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 127 fpm. The filaments are converged into yarn at a finish roll
• the yarn is then passed through an interfloor tube to an undriven air bearing separator roll with a speed of 3909 mpm
• the feed yarn is warp drawn on the Barmag STF1 draw unit at a draw ratio of 1.316X, a draw temperature of 60°C, an overfeed of 5%, was relaxed at ambient
• the resulting drawn yarn has a denier of 43.8 and an elongation of 53.1%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 80 dye according to the LMDR procedure, and rated for uniformity.
• the LMDR is a superior 7.1. Details of the process and yarn properties are provided in Table 1.
• Nylon 6,6 having an RV of ⁇ 50 is spun at a melt temperature of 290°C through a spinneret containing 17 capillaries of length 0.022" and diameter 0.015".
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 67 fpm.
• the yarn is then passed through an interfloor tube to an undriven air bearing separator roll with a speed of 3954 mpm
• the feed yarn is warp drawn on the Barmag STF1 draw unit at a draw ratio of 1.45X, a draw temperature of 60°C, an overfeed of 6%, was relaxed at 22°C and wound into a beam at a speed of 550 mpm.
• the resulting drawn yarn has a denier of 39.6 and an elongation of 30.6%.
• the drawn yarn is knit into a tricot fabric, dyed with the C.I. Acid Blue 80 dye according to the LMDR procedure, and rated for uniformity.
• the LMDR is a superior 7.4. Details of the process and yarn properties are provided in Table 1.
• Nylon 6, having an RV of 46 is spun at a melt temperature of 275°C through a spinneret containing 10 capillaries of length 0.010" and diameter 0.020".
• a quench cabinet is supplied with a cross-flow of 20°C quench air at an average velocity of ⁇ 67 fpm.
• the SOY yarn is not mechanically drawn and passes over no rolls before the wind-up but, because of the tension generated by the high speed spinning, the yarn is oriented sufficiently in the quench zone to give it an elongation of ⁇ 67.5% and a draw tension of 42.8 g.
• the yarn has a denier of 46.
• the feed yarn is warp drawn on the Karl Mayer DSST 50 draw unit at a draw ratio of 1.23, a draw
• the resulting drawn yarn had a denier of 40 and an elongation of 42%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 122 dye according to the LMDR procedure, and rated for uniformity.
• the uniformity rating is a superior 7.4.
• Nylon 66 having an RV of 65 is prepared as in example F, except that the windup (withdrawal) speed is 5300 mpm.
• the resulting 13 filament SOY feed yarn for warp-drawing has a denier of 50.5, an elongation of 73.5%, and a draw tension of 63 g.
• the feed yarn is warp draw on the Barmag STF1 draw unit at a draw ratio of 1.15X, a draw temperature of 60°C, an overfeed of 5%, was relaxed at 22°C and was wound into a beam at a speed of 550 mpm.
• the resulting drawn yarn had a denier of 46.5 and an elongation of 47%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 80 dye according to the LMDR procedure, and rated for uniformity.
• the uniformity rating is an excellent 7.6.
• s-caproamide units having an RV of 65 is prepared as in example J.
• the resulting 13 filament SOY feed yarn for warp-drawing has a denier of 50.0, an elongation of 76.1%, and a draw tension of 63 g.
• the feed yarn is warp drawn on the Barmag STF1 draw unit at a draw ratio of 1.30X, a draw temperature of 60°C, an overfeed of 5%, was relaxed at 118°C and was wound into a beam at a speed of 550 mpm.
• the resulting drawn yarn had a denier of 39.5 and an elongation of 41.7%.
• the drawn yarn is knit into a tricot fabric, dyed with C.I. Acid Blue 80 dye according to the LMDR procedure, and rated for uniformity.
• the uniformity rating is an excellent 7.6.
• Example II illustrates the effect of warp-drawing conditions on LMDR.
• the PDY feed yarn described in Example I - Part "F" above is warp drawn on the Barmag STF1 unit at various warp draw ratios and relaxation temperatures as indicated for items 1-13 in Table II.
• the resulting beams are warp knit into a 32 guage tricot fabric, dyed with C.l. Acid Blue 80 dye by the LMDR procedure, and rated for uniformity with the results being shown in Table II.
• Example III also illustrates the effect of warp-drawing conditions on LMDR.
• the SOY feed yarn described in Example I - Part "G" above is warp drawn on the Barmag STF1 unit at various warp draw ratios and relaxation temperatures as indicated for items 1-6 in Table III.
• the resulting beams are warp knit into a 32 gauge tricot fabric, dyed with C.I. Acid Blue 80 dye by the LMDR procedure, and rated for uniformity with the results shown in Table III.
• Example IV also illustrates the effect of warp-drawing conditions on LMDR.
• the SOY feed yarn described in Example I - Part "H" above is warp drawn on the Barmag STF1 unit at various warp draw ratios and relaxation temperatures as indicated for items 1-14 in Table III.
• the resulting beams are warp knit into a 32 gauge tricot fabric, dyed with C.I. Acid Blue 80 dye by the LMDR procedure, and rated for uniformity with the results should in Table IV.
• Example V also illustrates the effect of warp-drawing conditions on LMDR.
• the SOY feed yarn described in Example I - Part "J" above is warp drawn on the Barmag STF1 unit at various warp draw ratios and relaxation temperatures as indicated for items 1-8 in Table V.
• the resulting beams are warp knit into a 32 guage tricot fabric, dyed with C.I. Acid Blue 80 dye by the LMDR procedure, and rated for uniformity with the results shown in Table V.
• Example VI also illustrates the effect of warp-drawing conditions on LMDR.
• the SOY feed yarn described in Example I - Part "K" above is warp drawn on the Barmag STF1 unit at various warp draw ratios and relaxation temperatures as indicated for items 1-7 in Table VI.
• the resulting beams are warp knit into a 32 guage tricot fabric, dyed with C I. Acid Blue 80 dye by the LMDR procedure, and rated for uniformity with the results shown in Table VI.
• Example VII illustrates the effect of draw temperature on LMDR.
• the SOY feed yarn described in Example I - Part "J" above is warp drawn on the Barmag STF1 unit at various warp draw temperatures as indicated for items 1-8 in Table VII.
• the resulting beams are warp knit into a 32 gauge tricot fabric, dyed with C.I. Acid Blue 80 dye by the LMDR procedure, and rated for
• Example VIII illustrates the feasibility of warp drawing yarns containing MPMD.
• Three SOY feed yarns were used.
• Item J is the same yarn as is described in Example I - Part "J”.
• Item L was spun as described in Example I - Part "J", except that it contained 5% Me5-6, and Item M was also spun as described in Example I - Part "J” except that it contained 20% MPMD.
• These items were drawn on the Barmag STF1 unit at the same draw ratio, but at various relaxation temperatures and wound on a single-end winder.
• the resulting bobbins of yarn were knit into Lawson Tubing and all drawn items were dyed in the same dye bath with C.I. Acid Blue 122 using the LMDR dye procedure except that only relative dye shade was evaluated.
• Example IX illustrates that when yarns lack certain physical properties which are imparted by drawing, poor fabric uniformity can result.
• Item IX-1 is a warp drawn "feed" yarn of nylon 66 containing 5% by weight of nylon 6, which is similar to item K in Table I, except that the cross-section of the filaments in Item IX-1 is trilobal. Item IX-1 was beamed by normal beaming
• Procedure "8" is identical to the LMDR procedure except that the dye is Pontamine Fast Turquoise 8GL.
• Procedure "4" is identical to the LMDR procedure except that the surfactant Merpol DA is omitted.
• Procedures "4" and “8” are both structure sensitive and procedure "4" is even more sensitive to fine structure variations (that is, to variations in structure openess) than the LMDR procedure.
• Procedure "2” is a procedure in which the fabric is dyed for 60 minutes at 100°C in a bath containing 0.5% C.I. Disperse Blue 3, which is a leveling dye. Procedure "2" is used to identify configurational causes of dyed fabric non-unifomrity; that is,
• Warp drawing of uniform feed yarns to increase their initial modulus to values greater than about 15 g/d improves dyed fabric uniformity by reducing the
• PROC. 8 UNIFORMITY RATING 4.7 6.9
• PROC. 4 UNIFORMITY RATING 4.9 6.4
• PROC. 2 UNIFORMITY RATING 4.3 7.0
• Feed yarns used to prepare drawn yarns X-2 through 13, 18 and 19 are representative of region II feed yarns.
• Feed yarns used to prepare drawn yarns X-26 through 29, 31, 32, and 34 are representative of region III feed yarns.
• the apparent pore mobility (APM), derived from amorphous orientation, and the apparent pore volume (APV), derived from wide-angle x-ray were determined for the drawn yarns prepared with varying draw ratios (DR), draw temperatures (T D , and relaxation temperatures (T R ).
• DR draw ratios
• T D draw temperatures
• T R relaxation temperatures
• Drawn yarns providing LMDR > 6 and dye transition temperatures (T DYE ) less than about 65°C are found to have an APM greater than about (5-0.37 ⁇ 10 -4 APV), preferably greater than about 2, for an APV greater than about 4 ⁇ 10 4 cubic angstroms.

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• 1991
  • 1991-06-20 TW TW080104796A patent/TW200534B/zh active
  • 1991-06-21 EP EP91913502A patent/EP0536315B1/en not_active Expired - Lifetime
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