US3091015A - Drawing of nylon - Google Patents

Drawing of nylon Download PDF

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US3091015A
US3091015A US799054A US79905459A US3091015A US 3091015 A US3091015 A US 3091015A US 799054 A US799054 A US 799054A US 79905459 A US79905459 A US 79905459A US 3091015 A US3091015 A US 3091015A
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Prior art keywords
yarn
stage
birefringence
temperature
draw
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US799054A
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Zimmerman Joseph
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EIDP Inc
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EI Du Pont de Nemours and Co
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Priority to CA666693A priority Critical patent/CA666693A/en
Priority to IT595427D priority patent/IT595427A/it
Priority to IT555778D priority patent/IT555778A/it
Priority to NL208426A priority patent/NL112997C/xx
Priority to FR1154335D priority patent/FR1154335A/fr
Priority to DE19561260679 priority patent/DE1260679C2/de
Priority to GB20296/56A priority patent/GB811349A/en
Priority to BE549180A priority patent/BE549180A/xx
Priority to CH352451D priority patent/CH352451A/de
Priority to GB28654/58A priority patent/GB889144A/en
Priority to FR1210212D priority patent/FR1210212A/fr
Priority to BE571165A priority patent/BE571165A/xx
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US799054A priority patent/US3091015A/en
Priority to US260981A priority patent/US3093881A/en
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    • 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
    • D02J1/228—Stretching in two or more steps, with or without intermediate steps
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/61—Processes of molding polyamide

Definitions

  • a primary object of the present invention is to provide an improved process for drawing nylon filaments and yarns. Another object is to provide drawn polyamide filaments and yarns of improved quality. A particular object is to provide a process for controlled multiplestage drawing of synthetic linear polyamide filaments. Other objects, together with means and methods for attaining them, will be apparent from the following description.
  • a polyamide strand (filament, yarn, etc.) is subjected to a multiple-stage drawing operation with the ratio of drawn length to undrawn length (termed herein draw ratio, and repre sented by the symbol R in the first stage of the drawing operation being governed by the birefringence of the strand immediately prior to drawing.
  • B refers to the birefringence which for the present purpose is the absolute difference in refractive indexes along and perpendicular to the axis of a filament in unswollen condition.
  • birefringence as applied to multifilament yarns or strands herein refers, of course, to the birefringence of the filaments in those yarns or strands.
  • Equation 1 (area EFGH in the FIGURE) relates undrawn yarn birefringence to the first stage draw ratio where the undrawn yarn is packaged (lagged) before drawing.
  • Equation 2 (area ABCD in the FIGURE) applies to drawing operations wherein freshly extruded yarn is drawn, such as yarn supplied immediately from spinning. The Wider limits of processability permitted with fresh yarn is presently believed due to the reduced level of crystallinity exhibited by such yarn, which is relatively amorphous compared to yarn which has been lagged.
  • the extent of processability defined by each equation is based on operability of the drawing process, expressed in terms of filament breaks. Substantially no broken filaments are encountered during the first stage of a multi-stage drawing operation carried out according to Equations 1 or 2, and operation in the following second stage draw is also markedly improved over known drawing processes.
  • polyamide yarn of improved properties is produced in a multistage drawing process when a critical amount of draw is used in the first stage to provide a predetermined amount of molecular orientation, as illustrated in the examples.
  • Some orientation is produced in the spinning process, and is a function of spinning speed, polymer viscosity, quenching conditions, snubbing produced by yarn guides, etc. Such orientation is measured by determining the birefringence in filaments of the spun yarn.
  • a change in the orientation produced in spinning will require adjustment to a different machine draw ratio in the first stage.
  • the proper adjustment can be calculated if the equation (curve) relating draw ratio and orientation is first determined experimentally. This relation shows increasing orientation as draw ratio is increased. Since, according to the invention, it is necessary to produce a predetermined level of orientation in the drawn yarn of the first stage, the orientation to be introduced by the first stage machine draw ratio will be the difference between this predetermined level or orientation and the orientation produced in the spinning step. This difference is given mathematically by Equations 1 and 2, and is shown graphically in the FIGURE for the range of birefringence which may be practically achieved in spun yarn.
  • Equations 1 and 2 a novel and highly useful drawn yarn is produced.
  • This product is characterized not only by unusually attractive mechanical properties (high tenacity, high modulus, high work to break), but more significantly by its structural uniformity, evidenced by improved birefringence uniformity along the length of the individual filaments of the yarn. Such improvement is several fold over the best prior art yarns. It is this structural uniformity which characterizes the product produced by the process of this invention.
  • the limits of the equations defining the first stage draw ratio for freshly-spun and prepackaged yarn are established so as to enclose those areas of the FIGURE in which the standard deviation of the birefringence of the drawn yarn (as measured below) is equal to or less than the quantity 5/2 (T-3) X 10*, where T is the yarn tenacity in gms. per denier.
  • the birefringence profile of a drawn yarn is determined by measuring the hirefiringence at 1 millimeter intervals for representative 5 centimeter length samples taken from a plurality of yarn filaments from the same yarn bundle. Birefringence uniformity of the yarn is then expressed as the average of the standard deviations (hereinafter symbolized E for each of the individual filament samples, the term standard deviation having its usual statistical significance.
  • Equation 3 states that yarn drawn in accordance with the instant invention has E less than or equal to the quantity [5/2(T-3) l0- Within the family of yarns defined by Equation 3, certain species stand out as especially useful. Yarns having a tenacity T of at least about 5.5 grams per denier and an average standard birefringence deviation E less than 6x10- are useful in textile applications. Yarns having a tenacity T of at least about 7 grams per denier and an average standard birefringence deviation E less than 1.0) are useful in many lessdemanding industrial applications.
  • Yarns having a tenacity T of at least about 9 grams per denier and an average standard birefringence deviation E less than 1.5 10- are useful in industrial applications, such as in power transmission belting.
  • Particularly preferred yarns are those having a tenacity T of at least about 10 grams per denier and an average standard birefringence deviation E less than 1.0x 10 such yarns are useful in applications demanding the utmost in resistance to fatigue, such as encountered in most industrial applications, and, particularly, in tire cords.
  • the yarn of this invention may be composed of fiber-forming polyamides generally, especially polyhexamethylene adipamide or polycaproamide.
  • first stage of drawing is meant generally that drawing which occurs below the so-called forceto-draw transition temperature but above the second order transition temperature, both defined hereinafter. Otherwise, starting with an undrawn yarn, the stages of drawing are differentiated by the rather abrupt increase in slope of the drawing tension versus draw ratio relationship, which change occurs near the end of the first stage of drawing.
  • the quantity R refers to the first stage draw ratio and is conveniently measured by determining the relative peripheral speeds of the feed and draw rolls, provided there is substantially no slippage of the yarn thereon. Such slippage is readily prevented by customary means known to the art, such as by means of pinch rolls, multiple wraps, or the like.
  • the draw ratio as defined hereinabove refers to the ratio of drawn length to undrawn length of yarn in process; if such measurement is made (e.g., by a denier determination) at a later time on yarn samples which have been left free to retract, erroneous results may be obtained. To avoid this error, it is necessary to make correction for the slow retraction known to occur in polyamides which have been stretched beyond their elastic limit.
  • the temperature at which the critical first-stage drawing is conducted should be below, and that of the subsequent stage or stages above, what is denoted herein as the force-to-draw transition" temperature, at which a discontinuity exists in the relationship of a logarithmic function of the tension required to draw an undrawn filament to certain extent under certain conditions versus the reciprocal of the drawing temperature expressed in degrees on an absolute temperature scale.
  • Drawing usually is localized at a snubbing surface, such as a pin or plate about or over which the filaments pass, as shown in Patent 2,533,013 by Hume, who also discloses there an arrangement for two-stage drawing that can be used satisfactorily in the practice of this invention, provided there is maintained sufficient control over the extent of drawing which takes place in each stage.
  • a snubbing surface such as a pin or plate about or over which the filaments pass
  • the second-order transition temperature is about 50 C. and the force-to-draw transition temperature is in the vicinity of C., being about C. for polyhexamethylene adipamide; the melting temperature is about 265 C. for polyhexamethylene adipamide and about 215 C. for polycaproamide.
  • the force-to-draw transition temperature polyhexamethylene adipamide undergoes a reversible transition from hexagonal (above) to triclinic (below) crystallinity.
  • Determination of the force-to-draw transition temperature is accomplished conveniently upon filaments freshly produced at 275 yards per minute and forwarded from the spinning windup package at 2 /2 yards per minute to and about a hot steel snubbing pin one inch in diameter with chrome-plated matte finish and drawn thereby to 4 /2 times the original length (i.e., a 4.5x draw).
  • this invention is applicable to filaments and similar strands composed of synthetic linear polyamides generally; it is exemplified below in illustrative detail using, unless otherwise indicated, polyhexamethylene adipamide of 55 relative viscosity (e.g., prepared by the method of Spanagel, US. 2,163,636) formed in conventional manner (e.g., using the apparatus of Greenewalt, US. Patent No. 2,217,743) into a 140-filament yarn of about 4800 total denier. All physical testing is done on yarn which has been stored for at least 48 hours at 55% relative humidity and 75 F.
  • Tenacity is measured in a constant rate of extension machine (Instron Tensile Tester) in accordance with ASTM specifications (Ref. ASTM standards on Textile Materials, prepared by ASTM Committee D-13 on Textile Materials, pages 42-46, 523526, November 1956).
  • Industrial yarns are preconditioned at 55 relative humidity, 25 C.
  • a 10-inch sample is extended at a rate of 60% per minute. In general, a twist of 1-3 turns per inch is used to obtain clean breaks. Textile yarns are conditioned at 72% relative humidity; otherwise, the procedure is the same.
  • Tenacity is expressed in units of grams/ denier.
  • yarn is led directly from the usual spinning feed roll to pass about a heated /z-inch snubbing pin (one 360 wrap), to a set of rolls for controlling the amount of drawing in the first stage; the yarn then went directly to and over a relatively long heated surface (3 wraps at a 60 helix angle about a pipe 1 inch in diameter and 30 inches long), thence to another set of rolls for controlling the amount of drawing in this second stage, and finally to a Windup. Birefringence was determined throughout from observation of representative filaments between crossed plane-polarizing elements (e.g., Nicol prisms) using a Soleil Compensator for accuracy; the method is treated in detail by Heyn in Textile Research Journal 22, 513 (1952).
  • crossed plane-polarizing elements e.g., Nicol prisms
  • Freshly formed multifilament nylon having a bircfringence of 0.004 is advanced at 380 yards per minute to the first drawing stage.
  • the pin temperature is 75' C.
  • the draw ratio in the first stage is 3.3.
  • the temperature of the drawing surface in the second stage is 190 C., and the draw ratio is 1.77, giving a total draw of 584x.
  • Breakage frequency during drawing is 0.05 per pound, and the drawn yarn has a tenacity of 9.3 grams per denier (g.p.d.), elongation of 17.3%, and initial tensile modulus of 43 g.p.d.
  • Freshly formed nylon yarn having a birefringence of 0.0025 is advanced at 275 yards per minute to the first drawing stage.
  • the pin temperature is 75 C.
  • the draw ratio in the first stage is 3.6.
  • the yarn is fed then to the second stage, in which temperature is 230 C. and the draw ratio is 1.7, giving a total draw of about 6 X.
  • Breakage frequency during drawing is 0.10 per pound, and the drawn yarn has a tenacity of 9.0 g.p.d., elongation of 16.3%, and initial modulus of 42 g.p.d.
  • EXAMPLE III A freshly formed multifilament nylon having a birefringence of 0.004 is advanced at 380 yards per minute to the first drawing stage.
  • the pin temperature is carefully maintained at 100 C., and the draw ratio in the first stage is 3.4.
  • the temperature of the drawing surface in the second stage is 180 C., and the yarn makes only two helical wraps about the drawing element; the draw ratio is 1.68, giving a total draw of 5.7x.
  • the drawn yarn has a tenacity of 9.3 g.p.d., elongation of 16.0%, and initial modulus of 42 g.p.d.
  • Freshly formed multifilament nylon yarn having a birefringence of 0.006 is advanced at 440 yards per minute to the first drawing stage.
  • the pin temperature is 120 C.
  • the draw ratio in the first stage is 3.05.
  • the yarn is then fed by draw rolls to the second stage, where the temperature is 175 C., and the draw ratio is 1.85 giving a total draw of 5.65 X.
  • Breakage frequency during drawing is 0.7 break per 100 lbs. of yarn, and the drawn yarn has a tenacity of 9.5 g.p.d., elongation of 15.2%, and an initial modulus of 52.3 g.p.d.
  • Freshly formed nylon multifilament yarn having a birefringence of 0.011 is advanced at 700 yards per minute to the first drawing stage.
  • the pin temperature is 130 C.
  • the draw ratio in the first stage is 2.7.
  • the yarn is then fed to the second stage where it passes in three wraps 6 around the heated tube which has a temperature of about 185 C.
  • the draw ratio in this stage is 1.9, making a total draw of 5.2x No broken filaments are observed at the first draw surface.
  • the drawn yarn has a tenacity of 9.0 g.p.d., an elongation of 16.0, and an initial modulus of 47.7 g.p.d.
  • nylon is poly(hexamethylene adipamide) of 65 relative viscosity.
  • Freshly formed multifilament nylon having a birefringence of .0035 is advanced at 340 y.p.m. to the first drawing stage.
  • the pin temperature is 50' C. and the draw ratio in the first stage is 3.4.
  • the temperature of the drawing surface in the second stage is 195 C. and the draw ratio is 1.74, giving a total draw of 5.83
  • the break frequency during drawing is negligible, 3 broken filaments per minute being observed on' the draw roll.
  • the drawn yarn has a tenacity of 9.3 g.p.d., elongation of 16.4%, and initial tensile modulus of 60 g.p.d.
  • Samples of this yarn are allowed to relax free for 48 hours at 55% relative humidity at 20 C.
  • a load of 0.85 gram is then applied to each filament in order to maintain it in an extended position.
  • Representative 5 centimeter lengths are sampled, and the birefringence is determined at intervals of l millimeter.
  • Independent measurements of filament diameter are made at right angles to the path of light transmission in each of the retardation measurements in order to avoid errors due to ou t-of-round filaments.
  • the 51 readings for each sample are averaged, and the average birefringence of these filaments along with the average standard deviation (F are reported.
  • the average birefringence of the aboveexemplified yarn is 0.0625, and 5: ⁇ , is 5.30 10'
  • the above measurements on the drawn yarn of Example I give an average birefringence of 0.0625, and 5;; is 5.5 10
  • this technique is applied to the drawn yarn of Example IV, an average birefringence of 0.0612 results, with E of 576x10.
  • Freshly formed multifiiament nylon yarn having a birefringence of 0.0066 is advanced at 440 y.p.m. to the first drawing stage.
  • the pin temperature is C.
  • the draw ratio in the first stage is 3.2.
  • the yarn is then immediately fed to a second stage where the temperature is C., and the draw ratio is 1.77, giving a total draw of 5.65 Breakage frequency during drawing is .02 break per pound of yarn, and the drawn yarn has a tenacity of 9.2 g.p.d., elongation of 14.6%, and an initial modulus of 64 g.p.d.
  • the average birefringence of this yarn is 0.0612, and E is 5.76 10 EXAMPLE VIII
  • Freshly formed multifilarnent nylon yarn having a birefringence of 0.0035 is advanced at 340 y.p.m. to the first drawing stage.
  • the pin temperature is 55 C.
  • the draw ratio is 4.1.
  • the yarn is passed (1 wrap) over a 6-inch drum maintained at 162 C., then passes in three 60 wraps over a 3% inch pipe maintained at 180400 C.
  • the draw ratio in this stage is 153x, resulting in a total draw of 625x.
  • Breakage frequency during drawing is 0.012 break per pound, and the drawing yarn has a tenacity of 10.8 g.p.d., elongation of 14.8%, and initial tensile modulus of 70 g.p.d.
  • the average birefringence of this yarn is 0.0629; E is 4.28 l0"
  • the same results are obtained when the first stage draw pin is replaced by tandem pins of the same construction and run at about the same temperature.
  • the yarn takes /2 wrap (ca. 180) about each pin in this system.
  • Freshly formed multifilament nylon yarn having a birefringence of 0.0008 is advanced at 80 y.p.m. to the first drawing stage.
  • the pin temperature is 85 C.
  • the draw ratio in the first stage is 5.1.
  • the temperature of the drawing surface in the second stage is 198 C., and the draw ratio is 1.3, giving a total draw of 6.6x.
  • the break frequency during drawing is practically negligible, and the birefringence uniformity of the yarn is excellent.
  • EXAMPLE X As a comparison with the results in the above examples, the following table gives results obtained in a twostage drawing operation performed upon the undrawn yarn of Example VI, supplied to the first stage of drawing at a rate of 340 y.p.m. Drawing is carried out using the apparatus described in Example VIII. These results show over-all drawing Operability, expressed in terms of broken filaments per minute in the second stage of drawing at constant total draw ratio, for varying first stage draw ratios. These results further reflect the significance of Equation 2 and the improvement in operability resulting from drawing according to the present invention.
  • Breakage frequency during drawing in the second stage is .02 break per pound
  • the drawing yarn has a tenacity of 10.0 g.p.d. and an elongation of 13.2% and an initial modulus of 67 g.p.d.
  • the average birefringence of the drawn yarn is 0.0644, and E is 7.06Xl0-
  • the above-illustrated method (Example XI) is general, requiring only that the yarn be heated to a temperature above the force-to-draw transition temperature after drawing in the first stage, prior to interstage packaging. It is most useful with olyhexamethylene adipamide, taking advantage of the reversible crystalline transition which occurs at about the force-to-draw transition temperature.
  • the yarn is first heated over a hot pin, plate, or the like prior to such drawing to reachieve the desired hexagonal crystalline modification.
  • This method is highly advantageous in that it permits all of the advantages of a coupled spinning and drawing operation without necessitating the high windup speeds sometimes required when both stages of drawing are carried out in immediate sequence.
  • EXAMPLE XII Polyhexamethylene adipamide of 5 5 relative viscosity is spun in conventional manner at 400 yards per minute (y.p.m) to produce an 1180 denier yarn containing 34 filaments and exhibiting a birefringence of 0.004.
  • the yarn Upon being withdrawn from the spinning windup package, the yarn is led over an Alsimag snubbing pin ii inch in diameter heated to a tempearture of 55 C. by contact with the yarn, whereupon the yarn is drawn 3.5 X.
  • the yarn is passed in one wrap about %-inch polished steel tube 10 inches long heated to a temperature of C., whereupon the yarn is drawn an additional 1.6x.
  • the yarn has a tenacity of 8.9 g.p.d., elongation of 14.0%, and an initial modulus of 51 g.p.d. Operability of this process is good, giving only 20 breaks per 100 pounds and draw roll wraps for less than 15% of the total operation.
  • EXAMPLE XIII Polyhexamethylene adipamide is spun in conventional manner at 1200 yards per minute to produce a 230 denier yarn containing thirty-four filaments having a birefringence of 0.018.
  • the package of spun yarn is transferred from the spinning machine to a drawing machine, where the yarn is led over an Alsimag snubbing pin inch in diameter heated to a temperature of 55 C. by contact with the yarn, whereupon the yarn is drawn to 2.3 times its original length.
  • An intermediate set of tensioning rolls forwards the yarn to a inch heated steel tube about which it passes in a 180 Wrap. The steel tube is heated to a surface temperature of 180 C.
  • the yarn is thus drawn an additional 1.38x, for a total draw of 3.17 Wound up on a package at 440 y.p.m., the yarn has a tenacity of 5.3 g.p.d., elongation of 26%, and an initial modulus of 42 g.p.d.
  • the Operability of the process is good, since draw roll wraps occurred for less than 3% of the total operation.
  • EXAMPLE XIV Polycaproamide of 50 relative viscosity (relative viscosity as defined in US. 2,385,890) is spun into 1000 denier 74 filament yarn and is wound up at a speed of 350 y.p.m.
  • the spun yarn has a birefringence of 0.006.
  • the spinning package of yarn is transferred to a draw machine substantially as in Example XII, where it is drawn over an Alsimag snubbing pin heated to 80 C.
  • the draw ratio in this first stage is 3.2.
  • An intermediate set of tensioning rolls forwards the yarn to a %-inch heated steel tube about which it passes in a 180 wrap.
  • the steel tube is heated to a surface temperature of C.
  • the yarn is thereby drawn an additional 1.8x, for a total draw of 5.7x, and is wound up at a speed of 83 rolls.
  • EXAMPLE XV A copolymer of polyhexamethylene adipamide and polyhexamethyleneterephthalamide in the proportions of 70 parts to 30 parts (by weight), respectively, in spun to a yarn containing 140 filaments.
  • the yarn has a relative viscosity of 47.8 and a spun denier of 4300 and a birefringence of 0.015.
  • the yarn is forwarded to a drawing stage as in Example I at a rate of 440 y.p.m., where it is drawn 2.6x.
  • the pin over which it is drawn has a surface temperature of 110 C.
  • the yarn is then forwarded to a second drawing stage where it is given a 1.9 x draw while it wraps five times around a 1 .4 inch pipe heated to a surface temperature of 170 C.
  • the total draw ratio is 5.05.
  • the drawing process has acceptable operability, and the drawn yarn has a tenacity of 6.8 g.p.d., an elongation of 13.6%, and an initial modulus of 52.5 g.p.d.
  • EXAMPLE XVI Packaged multifilament nylon yarn having a birefringence of 0.0045 is advanced at 242 y.p.m. to the first drawing stage.
  • the pin temperature is 155 C.
  • the draw ratio in the first stage is 3.3x.
  • the yarn is then fed to the second stage in which the temperature is 205 0., and the draw ratio is 1.59X, giving a total draw of 5.24 Breakage frequency during drawing is less than .02 break per pound, and the drawn yarn has a tenacity of 8.7 g.p.d., an elongation of 17%, and initial. modulus of 50 g.p.d.
  • the average birefringence of this yarn is 0.0631 and the average standard deviation of the birefringence (5 obtained from birefringence profile measurements is 7.4lxlwhen R, is 3.0, and the total draw ratio and processing conditions the same as above, the average birefringence of the drawn yarn is 0.0644, and 3,, is 13x10.
  • R is increased to 4.5, all other conditions remaining the same, the average birefringence of the drawn yarn is 0.0618, E increasing to 3.6x 10- This latter run is outside the area of Equation 1.
  • EXAMPLE XVII The following example is representative of a typical prior art drawing process which is outside the area (EFGH of the FIGURE) of Equation 1.
  • spun yarn with a birefringence of .0045 is drawn from a package at 242 y.p.rn. over a 160 pin to a draw ratio of 4.9x.
  • the yarn is then fed directly to a hot plate maintained at 185 C. where it is drawn l.07 for a total draw of 5.24 There is no mechanical separation of the first and second stages of drawing of this process.
  • This yarn has an average birefringence of 0.0632 to 0.0641, and E ranging from 2.3 to 2.4x l0
  • the advantages of practicing the present invention include not only substantially decreased interruption (due to yarn breakage) in the processing of continuous nylon filaments, but also higher and more uniform quality characteristics in the drawn product; namely, a uniform birefringence profile.
  • the invention has been illustrated by the drawing of unswollen filamentary structures; presence of a swelling agent permits lowering of the optimum temperature for the drawing steps by about 5 to 20 degrees.
  • Suitable swelling agents include not only water, but also phenols and alcohols and like materials, such as those disclosed by Miles in Patent 2,289,377.
  • the optimum first stage drawing temperature will vary with the rate at which the yarn enters the drawing zone. In general, the lower the feeding speed, the closer the drawing temperature should be to the second-order transition temperature. In particular, it is preferable to select a first stage drawing temperature exceeding the transition temperature by from about 2 to 10 degrees for each hundred yards per minute of yarn feeding speed into the drawing zone.
  • the shape of the drawing element may also affect the optimum drawing temperature, and a gradient of temperature may exist on the drawing element, in which the case the temperature maximum at the region of maximum tension in the yarn will be the selected first stage drawing temperature.
  • the drawing element When drawing above the forcc-to-draw transition temperature, i.e., during the sec- 0nd stage of drawing, the drawing element should be such that snubbing is delocalized, as is accomplished when a heated pipe or plate is employed.
  • the two or more stages of drawing are not mechanically separated (e.g., Example III)
  • careful control must be imposed on the system in order to establish and maintain the desired draw ratio in each stage of drawing.
  • Important factors which control drawing in such systems include the rate of drawing, the relative temperatures of each drawing element, the geometry and surface friction characteristics of the drawing elements, their separation distance along the yarn path, the degree of snubbing and yarn contact time on each element, and the like. Often it is advantageous to effect either or both stages of drawing in a stepwise fashion.
  • Extension of the useful range of this invention may be achieved by increasing the as-spun yarn uniformity, both dimensionally and structurally. Such uniformity is accomplished using high quality polymer, higher spinning pack temperature, in order that the temperature gradient which usually exists across the spinneret face is minimized, and by optimizing polymer flow in the distribution space, quenching. and finish application to the individual yarn filaments.
  • Uniform as-spun yarn is characterized by denier and cross section uniformity, low and uniform spherulite content, interfilament birefringence uniformity, and the like.
  • the process of this invention permits the production of drawn nylon yarns having properties not heretofore attainable.
  • the nylon yarn products of this invention having a tensile strength of greater than 7 grams per denier and a birefringence average standard deviation of less than l.0 l() is particularly useful in all nylon yarn applications calling for high fatigue resistance, in which respect known nylon yarns have been found wantmg.
  • the nylon yarn products having a tenacity of at least 10 and a birefringence average standard deviation of less than l.0 10- exhibit at least a two-fold improvement over known nylon yarns in fatigue resistance as measured by a conventional disc fatigue test.
  • nylon yarn products having a birefringence average standard deviation of less than 6X10- are very exceptional in this respect, and in addition, are characterized by particularly uniform dyeing characteristics.
  • the latter yarns are substantially superior to known nylon yarns even at low tensile strengths.
  • Exemplary polyamides useful for preparing the novel 1 1 yarns of this invention include those linear polyamides disclosed in US. 2,071,251; US 2,071,253; and U.S. 2,130,948.
  • the improvement comprising passing the strand into a first stage of drawing such that the ratio of drawn length to undrawn length is constant and equal to R and R being determined by the equation where B is the average birefringence per filament in the strand immediately prior to drawing, said first stage of drawing being followed by a second stage of drawing.
  • a process comprising drawing an undrawn birefringent polyarnide strand, which has been packaged and which has a second-order transition temperature of about 50 C. and a force-to-draw transition temperature of about 150 C., in a plurality of stages, the first stage having a constant draw ratio R; as determined by the equation where B is the average birefringence per filament in the undrawn strand, at a drawing temperature between about 50 C. and about 150 C. and further drawing the filament at a temperature above 150 C. but at least 20 C. below the melting temperature of the polyamide.
  • B is the average birefringence per filament in the undrawn strand, a second stage of drawing following the first stage.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Artificial Filaments (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
US799054A 1955-06-30 1959-03-12 Drawing of nylon Expired - Lifetime US3091015A (en)

Priority Applications (14)

Application Number Priority Date Filing Date Title
IT595427D IT595427A (xx) 1955-06-30
IT555778D IT555778A (xx) 1955-06-30
CA666693A CA666693A (en) 1955-06-30 Drawing of nylon
NL208426A NL112997C (xx) 1955-06-30 1956-06-27
DE19561260679 DE1260679C2 (de) 1955-06-30 1956-06-29 Verfahren zur mehrstufigen verstreckung von faeden aus synthetischen linearpolyamiden
GB20296/56A GB811349A (en) 1955-06-30 1956-06-29 Improvements in or relating to the drawing of polyamide structures and especially nylon filaments
FR1154335D FR1154335A (fr) 1955-06-30 1956-06-29 Procédé pour l'étirage des fibres de polyamides
BE549180A BE549180A (xx) 1955-06-30 1956-06-30
CH352451D CH352451A (de) 1955-06-30 1956-06-30 Verfahren zur Herstellung eines Nylonfadens
GB28654/58A GB889144A (en) 1955-06-30 1958-09-05 Improvements in the drawing of polyamide yarns
FR1210212D FR1210212A (fr) 1955-06-30 1958-09-10 Procédé pour l'étirage du nylon
BE571165A BE571165A (xx) 1955-06-30 1958-09-12
US799054A US3091015A (en) 1955-06-30 1959-03-12 Drawing of nylon
US260981A US3093881A (en) 1955-06-30 1963-02-26 Oriented nylon filaments

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US352451XA 1955-06-30 1955-06-30
US889144XA 1957-09-12 1957-09-12
US799054A US3091015A (en) 1955-06-30 1959-03-12 Drawing of nylon
US260981A US3093881A (en) 1955-06-30 1963-02-26 Oriented nylon filaments

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US3091015A true US3091015A (en) 1963-05-28

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US799054A Expired - Lifetime US3091015A (en) 1955-06-30 1959-03-12 Drawing of nylon
US260981A Expired - Lifetime US3093881A (en) 1955-06-30 1963-02-26 Oriented nylon filaments

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Application Number Title Priority Date Filing Date
US260981A Expired - Lifetime US3093881A (en) 1955-06-30 1963-02-26 Oriented nylon filaments

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US (2) US3091015A (xx)
BE (2) BE549180A (xx)
CA (1) CA666693A (xx)
CH (1) CH352451A (xx)
DE (1) DE1260679C2 (xx)
FR (2) FR1154335A (xx)
GB (2) GB811349A (xx)
IT (2) IT555778A (xx)
NL (1) NL112997C (xx)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3184821A (en) * 1961-06-29 1965-05-25 Celanese Corp Treatment of filamentary material
US3382307A (en) * 1963-07-23 1968-05-07 Snia Viscosa Process for the stretching of polyamidic fibres
US3472016A (en) * 1966-07-11 1969-10-14 American Enka Corp Synthetic yarns,fabrics and processes for making the same
US3481136A (en) * 1967-12-11 1969-12-02 Celanese Corp Process for producing polyester yarn
US4496630A (en) * 1982-02-06 1985-01-29 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties and their production
US4504545A (en) * 1981-09-08 1985-03-12 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties and their production
FR2553794A1 (fr) * 1983-10-20 1985-04-26 Asahi Chemical Ind Fibre de polyhexamethylene adipamide ayant une haute stabilite dimensionnelle et une forte resistance a la fatigue, et procede pour sa preparation
US4701377A (en) * 1985-02-20 1987-10-20 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties, and their production
US4758472A (en) * 1982-07-08 1988-07-19 Asahi Kasei Kogyo Kabushiki Kaisha High tenacity polyhexamethylene adipamide fiber
US5034182A (en) * 1986-04-30 1991-07-23 E. I. Du Pont De Nemours And Company Melt spinning process for polymeric filaments
US5141700A (en) * 1986-04-30 1992-08-25 E. I. Du Pont De Nemours And Company Melt spinning process for polyamide industrial filaments
US5279783A (en) * 1992-01-30 1994-01-18 United States Surgical Corporation Process for manufacture of polyamide monofilament suture
US5349044A (en) * 1992-01-30 1994-09-20 United States Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide

Families Citing this family (9)

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Publication number Priority date Publication date Assignee Title
US3111364A (en) * 1959-05-13 1963-11-19 American Enka Corp Process for drawing a continuous, unwashed, undrawn polycapolactam filament
US3379810A (en) * 1963-08-02 1968-04-23 Toyo Rayon Co Ltd Process for the manufacture of high tenacity nylon filaments
US3402152A (en) * 1964-05-15 1968-09-17 Monsanto Co Process for preparing a polyamide
US3386967A (en) * 1965-01-19 1968-06-04 Allied Chem Polycaproamide having excess number of carboxyl end groups over amino end groups
NL135751C (xx) * 1965-03-26
US3321448A (en) * 1965-09-16 1967-05-23 Du Pont Nylon staple fiber for blending with other textile fibers
JPS554843B2 (xx) * 1972-06-08 1980-02-01
JPS57130A (en) 1980-05-30 1982-01-05 Unitika Ltd Melt-moldable copolyamide having aromatic amide unit
GB2101522B (en) * 1981-01-26 1984-05-31 Showa Denko Kk Producing high tenacity monofilaments

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US2199411A (en) * 1938-11-01 1940-05-07 Du Pont Artificial structure and method for producing same
US2278888A (en) * 1938-11-02 1942-04-07 Du Pont Artificial structure and process for producing same
US2289232A (en) * 1939-07-14 1942-07-07 Du Pont Method and apparatus for producing filamentary structures
US2455173A (en) * 1946-05-25 1948-11-30 Du Pont Yarn treating apparatus
US2474927A (en) * 1947-06-24 1949-07-05 Ray C Young Cord stretching apparatus
US2533013A (en) * 1949-04-27 1950-12-05 Du Pont Method and apparatus for the twostage draw of synthetic funicular structures
US2611923A (en) * 1949-08-31 1952-09-30 Du Pont Method and apparatus for the drawing of synthetic funicular structures
US2637893A (en) * 1949-03-12 1953-05-12 Shaw Gilbert Artificial filament
US2778057A (en) * 1953-04-02 1957-01-22 Stanley M Clark Method and apparatus for continuously stretching plastic film
US2807863A (en) * 1956-06-22 1957-10-01 Du Pont Multi-step stretching of nylon cords
US2874410A (en) * 1954-06-30 1959-02-24 Du Pont Apparatus for uniformly drawing a plurality of filaments

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DE918833C (de) * 1942-07-01 1954-10-07 Bayer Ag Verfahren zur Herstellung von Faeden, Draehten, Baendchen u. dgl. aus hitzeempfindlichen, polymeren Vinylverbindungen in zwei Stufen
BE465536A (xx) * 1942-11-03
BE498035A (xx) * 1947-05-30
BE482722A (xx) * 1947-05-30
US2556295A (en) * 1947-07-23 1951-06-12 Du Pont Process of drawing formed structures of synthetic linear polyesters
US2615784A (en) * 1949-12-20 1952-10-28 Du Pont Polyethylene terephthalate monofils drawn and heat set for use as bristles
BE512777A (xx) * 1951-07-12

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US2199411A (en) * 1938-11-01 1940-05-07 Du Pont Artificial structure and method for producing same
US2278888A (en) * 1938-11-02 1942-04-07 Du Pont Artificial structure and process for producing same
US2289232A (en) * 1939-07-14 1942-07-07 Du Pont Method and apparatus for producing filamentary structures
US2455173A (en) * 1946-05-25 1948-11-30 Du Pont Yarn treating apparatus
US2474927A (en) * 1947-06-24 1949-07-05 Ray C Young Cord stretching apparatus
US2637893A (en) * 1949-03-12 1953-05-12 Shaw Gilbert Artificial filament
US2533013A (en) * 1949-04-27 1950-12-05 Du Pont Method and apparatus for the twostage draw of synthetic funicular structures
US2611923A (en) * 1949-08-31 1952-09-30 Du Pont Method and apparatus for the drawing of synthetic funicular structures
US2778057A (en) * 1953-04-02 1957-01-22 Stanley M Clark Method and apparatus for continuously stretching plastic film
US2874410A (en) * 1954-06-30 1959-02-24 Du Pont Apparatus for uniformly drawing a plurality of filaments
US2807863A (en) * 1956-06-22 1957-10-01 Du Pont Multi-step stretching of nylon cords

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3184821A (en) * 1961-06-29 1965-05-25 Celanese Corp Treatment of filamentary material
US3382307A (en) * 1963-07-23 1968-05-07 Snia Viscosa Process for the stretching of polyamidic fibres
US3472016A (en) * 1966-07-11 1969-10-14 American Enka Corp Synthetic yarns,fabrics and processes for making the same
US3481136A (en) * 1967-12-11 1969-12-02 Celanese Corp Process for producing polyester yarn
US4624816A (en) * 1981-09-08 1986-11-25 Toyo Boseki Kabushiki Kaisha (Toyobo Co., Ltd.) Process for the manufacture of polyamide fibers
US4504545A (en) * 1981-09-08 1985-03-12 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties and their production
US4496630A (en) * 1982-02-06 1985-01-29 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties and their production
US4758472A (en) * 1982-07-08 1988-07-19 Asahi Kasei Kogyo Kabushiki Kaisha High tenacity polyhexamethylene adipamide fiber
US4621021A (en) * 1983-10-20 1986-11-04 Asahi Kasei Kogyo Kabushiki Kaisha Polyhexamethylene adipamide fiber having high dimensional stability and high fatigue resistance, and process for preparation thereof
FR2553794A1 (fr) * 1983-10-20 1985-04-26 Asahi Chemical Ind Fibre de polyhexamethylene adipamide ayant une haute stabilite dimensionnelle et une forte resistance a la fatigue, et procede pour sa preparation
US4701377A (en) * 1985-02-20 1987-10-20 Toyo Boseki Kabushiki Kaisha Polyamide fibers having improved properties, and their production
US5034182A (en) * 1986-04-30 1991-07-23 E. I. Du Pont De Nemours And Company Melt spinning process for polymeric filaments
US5141700A (en) * 1986-04-30 1992-08-25 E. I. Du Pont De Nemours And Company Melt spinning process for polyamide industrial filaments
US5279783A (en) * 1992-01-30 1994-01-18 United States Surgical Corporation Process for manufacture of polyamide monofilament suture
US5349044A (en) * 1992-01-30 1994-09-20 United States Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide
US5405358A (en) * 1992-01-30 1995-04-11 United States Surgical Corporation Polyamide monofilament suture
US5540717A (en) * 1992-01-30 1996-07-30 U.S. Surgical Corporation Polyamide monofilament suture manufactured from higher order polyamide

Also Published As

Publication number Publication date
NL112997C (xx) 1966-07-15
FR1210212A (fr) 1960-03-07
GB811349A (en) 1959-04-02
FR1154335A (fr) 1958-04-04
IT555778A (xx)
IT595427A (xx)
DE1260679B (de) 1968-02-08
US3093881A (en) 1963-06-18
CH352451A (de) 1961-02-28
CA666693A (en) 1963-07-16
DE1260679C2 (de) 1977-01-20
BE571165A (xx) 1958-09-30
BE549180A (xx) 1956-07-14
GB889144A (en) 1962-02-07

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