Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
• • 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
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/90—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyamides
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/88—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/92—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polycondensation products as major constituent with other polymers or low-molecular-weight compounds of polyesters
• • 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
  • Y10S57/00—Textiles: spinning, twisting, and twining
  • Y10S57/902—Reinforcing or tyre cords
• • 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
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2973—Particular cross section

Definitions

• the filaments produced by this invention are prepared from a matrix-forming polyamide having a relative viscosity in 90 percent formic acid of about 40 to 65 when the polyester constituent comprises at least 20 percent by weight thereof.
• Twilley provides a spinnable dispersion by capping the primary amino groups with a terminating agent such as monocarboxylic acid, dicarboxylic acid, isocyanate, and the like.
• a terminating agent such as monocarboxylic acid, dicarboxylic acid, isocyanate, and the like.
• Using such terminated polyamides it is possible as disclosed by Twilley to form a finely divided, homogeneous dispersion of molten polyester in a melt of fiber-forming synthetic linear polyamide (i.e. nylon), employing the equipment normally used when nylon is melted in an extruder; and it is possible to spin such dispersions from the melt by use of essentially conventional nylon melt spinning techniques.
• a commercially important consideration in spinning multifilament yarn on a large scale is the yield of first quality yarn obtained from the starting polymer.
• the most troublesome of these malfunctions in the spinning of the Twilley dispersions have been found to be occurrences, at frequently considerably higher than usual in commercial nylon-6 yarn produc- 3,470,686 Patented Oct. 7, 1969 tion, of drips in Spinning, and breaks during drawing of the mnltifilament yarn to impart high tenacity.
• the continuous multifilament yarn which is produced is of superior quality to that obtained when any of the above four parameters are outside their critical ranges.
• the multifilament yarn obtained is materially improved over that obtained using conditions outside the ranges of this invention.
• the filaments obtained by this invention are found to contain in each transverse cross section a much larger number of reinforcing polyester fibrils than are produced from like blends spun otherwise; this contrast remaining true even when the conventional operation of the nylon extruder is modified in the comparison tests, to produce the same degree of dispersion of polyester in the melt as is formed when operating in accordance with this invention.
• the effects of spinneret shear is particularly important as will appear below.
• the average diameters of the fibrils in yarn of this invention, drawn at 5:1 draw ratio, are not over 0.15 microns.
• the fibrils in the drawn yarn obtained by the present process have about 0.05 to 0.15 micron average diameter in yarn drawn 5 X (i.e. drawn at draw ratio of 5: 1) and spun from about 25-60 parts by weight of PET (polyethylene terephthalate) and correspondingly -40 parts of polycaproamide.
• the average number of fibrils in the 5X drawn polycaproamide yarns of this invention, per 1000 sq. microns transverse area, is at least 15,000 and in the best mode of operation is from at least 30,000 to as high as 1,000,- 000.
• the lengthzdiameter ratio of these fibrils of preferred operations averages at least 1,500: 1.
• typical drawn fibrils per this invention have progressively smaller average diameters, ranging about 0.02 micron, about 0.03-0.04 micron, and about 0.04-0.06 micron average diameter respectively in the yarn drawn X.
• the average number of fibrils per transverse 1000 sq. micron area of 5 drawn yarns of this invention, having 4-20 parts of polyester dispersed in correspondingly 96-80 parts of nylon by weight, is typically about 50,000-1,000,000.
• the 5X drawn yarns of this invention contain a minimum of 30,000 fibrils per average, 1,000 sq. micron transverse area.
• properties are averages arrived at by systematically sampling large quantities of yarn produced under given conditions, in quantities ranging from scores to hundreds of pounds for laboratory production, and hundreds to thousands of pounds for pilot plant production.
• verification of high performance levels requires data from the spinning and drawing of several thousands of pounds of yarn produced under given conditions, for the reason that at high performance levels, the combined occurrence of drips and breaks is of the order of or per thousand pounds of polymer spun.
• data obtained on laboratory scale and those on pilot plant scale are so indicated.
• a drip catcher is provided at the bottom of the quench stack, to detect the large blob and signal the operator to remove the package of yarn being wound up, wipe the spinneret, and start a new yarn package.
• the frequency of these drips is counted and is reported herein as drips per 1,000 pounds of polymer processed. In preferred operations in accordance with this invention, the drips average no more than 5 per 1,000 pounds.
• one segment of yarn e.g. formed from non-homogeneous melt
• this segment will break, e.g. in the drawing zone, and the drawing operation must be shut down and restarted.
• Such occurrences are called drawing breaks.
• Their frequency is reported herein as breaks per 1,000 pounds of first quality yarn produced.
• the sum of drips and breaks measures performance as reported herein. It will be appreciated that breaks can generally be reduced by reducing the draw ratio; however this will generally result in lowering the tensile strength and modulus of the yarn.
• the preferred undrawn yarns produced according to this invention are drawable by at least 5 without more than 10 breaks per 1,000 pounds on the average.
• melt viscosity (poises).As reported herein, measured by use of an Instron Melt Rheometer with 50 mils. diameter capillary 4 inches long, and with a conical entrance having angle of convergence of 60 (i.e. elements at opposite sides of the entrance cone converge in the direction of flow, at an angle of 60 at the apex). The melt viscosities are standardized to a temperature of 275 C. and velocity gradient of 3,000 reciprocal seconds.
• Apparent pipe and spinneret capillary shear (sec. Expressed herein as linear velocity gradient through each pi e, or each capillary hole of the spinneret, in reciprocal seconds, under the assumption that viscosity is constant.
• q is the volumetric flow per second per pipe or spinneret hole, e.g. cubic feet per second per hole, and r is the radius of the pipe or the spinneret hole capillary in the same linear units as for q, e.g. feet.
• Jet velocity (feet per minute).-Given by the formula: q/irr wherein q is the volumetric flow in cubic feet per minute per hole, and r is the radius of the spinneret capillary in feet.
• Nylon 6 polycaproamide
• PET polyethylene terephthalate
• Melt bulge (mm.).--A bulge with diameter greater than that of the spinneret capillary, observed in emerging molten filaments just below their point of emergence from the spinneret. Diameter of melt bulge is measured from photographs of the emerging filaments.
• the molten filaments are cut a few inches below the spinneret, releasing the take-up tension on the filaments being extruded; and the forward flow of molten polymer from the spinneret holes is collected on a tray in the form of relatively thick filaments which quickly solidify on the tray.
• a three-milligram sample is dissolved at 25 C. in 200 cc. of aqueous formic acid which dissolves the nylon component and leaves a dispersion of the polyester component in the aqueous formic acid solution.
• the polyester is in the form of spherical and slightly elongated particles.
• Polyester fibril lengths in undrawn yarn are averages, measured from photomicrographs of lengthwise sections of undrawn yarn stained with a dye for the nylon ingredient which does not dye the polyester; e.g. by immersion in a boiling 0.07% aqueous solution of Brilliant Acid Blue dye for one hour.
• N Number (N) of polyester fibrils/ 1,000 sq. microns of traverse filament area.-As reported herein, (N) is calculated from the above defined diameter (a') of polyester fibrils in drawn yarn by the formula:
• Solid polymer moisture content (percent by wgt.).-A sample from a sealed container of the polymer (about 5 grams) is Weighed to 0.1 mg. precision under strictly anhydrous conditions in a vial, then is maintained at reduced pressure (100 mm. Hg absolute) and at 185 C. for 2 hours. The pressure of the evolved Water vapor, exerted on an oil manometer, is measured. The Water content of the sample is determined from the measurement of water vapor pressure, by use of a calibration curve.
• Tensile strengths are those measured on the Scott IP-4 Tensilometer. (Each determination is the average of five breaks per card.)
• Fatigue resistance is measured (in minutes at 30 psi.) by ASTM Standard Test of 1964, Part 25, Test D- 885 upon two-ply (2 x 840, 12Z x 128 twist) tensilized cord (Goodyear Tube Fatigue Test).
• Dye strengths and uniformity.Dyeing is accomplished with Color Index Disperse Blue 3 (a water insoluble anthraquinone dye) using 0.2% by weight on fabric or yarn in a dye bath at C. (205 F.).
• Dye strength (based on nylon as and uniformity (freedom from streaks and bands, rated from (1) for excellent to (4) for poor) is judged by a panel of skilled observers.
• Birefringence A measure of the extent of molecular orientation in the direction of the filament axis, defined as the difference in the refractive index measured longitudinally of the filament vs. that measured perpendicular to the axis of the filament.
• mixing shear in the present process depends upon variables which include the proportion of polyester in the dispersion, the time of mixing, and the time and shear during transfer of the molten dispersion from the mixing apparatus used.
• a useful criterion of proper mixing shear has been found to be the particle size (i.e. average diameter) of the dispersed polyester particles in the extrudate, collected free of tension in molten form just below the spinneret. These polyester particles are observed microscopically in differentially stained cross sections of the extrudate to be spherical or slightly elongated. Similar sized polyester particles are observed in polymer blends collected at various points between the extruder and the inlet face of the spinneret.
• the average particle diameter of the polyester dispersed in the molten nylon is somewhat smaller, the nearer the point of sampling is to the extruder outlet; e.g. 1.39 microns at the extruder outlet, 1.66 microns over the inlet face of the spinneret, and 1.80 microns in the collected extrudate for 30/70 weight blends of polyethylene terephthalate/nylon-6 have been observed in typical operations in accordance with this invention. It will be appreciated, accordingly, that results obtained by high mixing shear can and should be preserved by transferring the dispersion in relatively narrow pipes which will exert continuing shear such that the particles do not increase unduly in size during transfer.
• the above parameters can be correlated over the range to about 60/40 ratios by weight of polyester/nylon by the following relation between desired average particle diameter D in the extrudate in microns; parts by weight P of the minor ingredient of the blend, based on the polyester/ polyamide mixture as 100; and number of rings C (C being 1 or 2), in the polyester chain unit:
• polyester is polyethylene terephthalate in weight proportion of 30/ 70 with nylon
• P is 30 and D in accordance with the above formula is at most 1.85 microns.
• the standard deviation of these diameters turns out to be about 0.25 micron; and for lower average diametersthe standard deviation is also lower; so that 0.25 micron represents a maximum for standard deviation of the polyester particle diameters at desired particle size.
• polyester particle diameter (D) in the extrudate (in microns) in accordance with this invention will generally be in the range given by:
• spinneret shear in terms of velocity gradient through the spinneret hole, which must be used to obtain the excellent performance which may be accomplished by this invention start well above the values (about 2,000 reciprocal seconds) ordinarily used in commercial spinning of nylon. Marginal performance starts at about 3,000 reciprocal seconds and generally improves as the velocity gradient increases. Velocity gradients through the spinneret hole of at least 5,000 reciprocal seconds, and still higher values up to about 30,000 reciprocal seconds are beneficial. Above a velocity gradient of about 30,000 reciprocal seconds the benefiits of intensive spinneret shear appear to drop off.
• Temperature in the molten blend is a variable which must be controlled within limits, to obtain the optimum spinning performance and yarn quality.
• the temperature should be near to that conventional for spinning nylon-6 alone, even though the polyester ingredient of the dispersions spun in the process of this invention will usually have a higher melting point than the nylon ingredient and the melt viscosity of the blend may be higher than in conventional nylon-6 spinning.
• the blend melt viscosities can be 2,000 or more poises at 275 C.
• Mixing and spinning temperatures of the melt for the present process are about 275 (1:10" C. It will be appreciated that shearing action increases the polymer temperature, so the temperatures in the extruder walls should be correspondingly lower. Preferably about 260 C. in the extruder metering zone. Therefore at very high shear it may be necessary to cool the extruder by a fan or equivalent means.
• temperatures measured at a distance of A" from the outermost ring of filaments and A" from the spinneret face are desirably in the range 310 C. to 400 C.
• melt bulge A phenomenon common to melt spinning of linear polymers is the so-called melt bulge normally observed in the running molten filament about 1 mm. below the outlet from the spinneret hole.
• the diameter of this bulge will exceed the diameter of the spinneret hole and will vary depending upon the polymer being spun, its viscosity, the jet velocity, the tension on the filament, and the geometry of the hole including the geometry of the entrance to the hole.
• This melt bulge is considered to be due to release of shear stress and pressure on the melt.
• the molecules With the resulting freedom for relieving strain along the polymer molecule, the molecules change shape, e.g. by coiling, folding, etc.
• melt bulge like that just described but much larger is observed about 1 cm. below the spinneret face.
• This latter bulge typically has a diameter from about 0.6 mm. to about 1.7 mm. in polyethylene terephthalate/nylon-6 blends, varying with polyester proportions and the spinning conditions. It is this large bulge which is referred to hereinafter as the melt u ge.
• the molten filament will snap back like rubber, forming a blob at the point where the melt bulge had about its maximum diameter.
• filament breaks tend to occur at or near the melt bulge.
• the tendency to break at that point probably arises from strains due to the changing flow pattern as the polymer passes into the zone of maximum melt bulge. If those strains can be reduced, minor inhomogeneities which would otherwise cause filament rupture and drips are harmless, and better spinning performance can be obtained.
• melt bulge diameter will not exceed at most 1.4 mm.', and in preferred operations is not over 1.2 mm.
• favorable control of this parameter of melt flow into the spinneret capillary cooperates with high mixing shear in and beyond the extruder, i.e. with a critical fineness of the dispersion obtained, and with high spinneret shear and also with temperature maintained throughout the melt at 275:l0" C.; to afford major benefits in spinning and drawing performance when all these 4 parameters are given their critical values.
• the tension is related to the extent to which the filament is elongated in being taken up, and this in turn is proportional to the stack draw down, i.e. the take-up speed divided by the jet velocity of the molten polymer stream.
• Higher jet velocities thus allow lower tension on the molten filament at 10 given throughput and wind-up speeds; the higher jet velocities are also beneficial in reducing the diameter of the melt bulge. It has been found desirable in the process of this invention to utilize a stack draw down of at least 10 but not over and a jet velocity of at least 25 feet/min.
• the maximum jet velocity to be used depends on factors such as polymer viscosity, quench air flow, etc. and is limited by the fact that at excessive jet velocities the extruded filaments develop a melt bulge which intermittently varies in shape, producing irregularities in filament denier, etc. In operations in accordance with this invention the jet velocities ordinarily used do not exceed about 200 ft./min.
• polyamide component is polycaproamide terminated by a dicarboxylic acid as described in copending Twilley US application Ser. No. 426,632, filed Jan. 19, 1965; which polycaproamide has not over 10 m.eq. (milliequivalents) of primary amino groups per kg. (kilogram) of polyamide and has a formic acid relative viscosity (ASTM D-789-62T) in the range of about 4065 (washed and dried) for 20-50 weight percent polyester and 40-100 FAV for polyester weight concentration below about 20%.
• These high viscosity polyamides have high melt viscosities in the range of about 600-3300 poises at 275 C.
• the process of this invention is not confined to use with such polyamides, however, but can be used to spin even polyamides having say 100 m.eq. of end groups and more than 40 m.eq. of primary amino groups per kg. of polyamide.
• the polyester ingredient of the dispersion can have relatively low viscosity.
• Polyesters can be used which reduce the melt viscosity of the dispersion as compared to that of the nylon ingredient alone, e.g. polyethylene terephthalate with melt viscosity of 400 poises and reduced discosity of 0.45 dl./ gm. can be used.
• Polyester such as specifically polyethylene terephthalate having a reduced viscosity as low as 0.45 is marginal in utility for fiber formation when spun as such from the melt. The fact that such polyester is valuable for use in the process and product of the present invention may be connected with the fine diameter of fibril produced by the present process.
• a relatively fluid polyester so that it can easily be elongated in the melt.
• the viscosity should nevertheless be adequte to permit cold drawing i.e. permanently elongating an undrawn filament of the polymer by drawing at a. temperature below the polymer fusion temperature whereby the polymer generally displays, by X-ray, orientation along the filament axis.
• a minimum reduced viscosity for the polyester ingredient will usually be about 0.3 dl./gm.
• the polyester and polyamide should have low and uniform moisture content, when subjected to melting, preferably not over 0.02% by weight moisture and particularly 0.01% by weight or less moisture.
• the polymer blends will generally contain additives such as heat and/or light stabilizer, delustrant, pigment, antistat, lubricant, etc. appropriate to the intended end use, as employed in nylon or in polyester.
• the blends can also contain bridging agents to increase the wetability or dispersibility of polyester by nylon, whereby to facilitate forming and maintaining a dispersion of molten polyester particles in molten nylon.
• the filaments of undrawn yarn produced in accordance with this invention will contain fine polyester fibrils dispersed therein, mainly lying lengthwise along the filament axis.
• the fibril lengths usually average about 20l00 microns and the fibril diameters average from about 0.04 micron to about 0.4 micron.
• These undrawn yarns are lubricated by the usual lube roll and wound into a package at the usual deniers, e.g.
• the undrawn yarns produced as above outlined can be drawn with or without heating while drawing, to impart molecular orientation along the filament axis, by methods conventionally used for nylon yarns; and can be further treated, e.g. heat treated for relaxation of strains, coated with finishes, crimped, twisted and/or entangled, etc. by procedures used for nylon yarns whereby to adjust and lower the levels of shrinkage, creep, etc.; impart desired friction characteristics; impart bulk; improve runnability; etc.
• the yarns produced in accordance with the invention and processed for uniform denier, uniform molecular orientation, etc. to promote uniform dyeability as required in carpets, textiles, etc. will still have relatively high tensile modulus both dry and wet, after being heat relaxed to lower the shrinkage level to suit the end use.
• These yarns also show a high level of liveliness or resilience as measured by Work Recovery. They are particularly useful in upholstery; in carpeting, e.g. loop pile tufted carpets from texturized yarn; in stretch fabric from false-twisted yarn; in knitted fabric; in staple for blending with e.g.
• cotton in general for application of fibers requiring one or more of the following: high tensile modulus both when dry and when hot and wet; low shrinkage; high abrasion resistance; high bulk resilience; and low water absorption high and low being relative to like yarn composed only of the nylon ingredient of the blend, as conventionally produced.
• polyester fibrils are greatly elongated and lie in the direction of the filament axis.
• these fibrils are discrete polyester fibrils in the nylon matrix; whereas in compositions of this invention having higher polyester content, from about 40/60 to about 60/40 weight ratios with nylon, some of the polyester fibrils are interconnected to form a network Within the nylon matrix and the remainder of the polyester is in the form of discrete fibrils in the nylon.
• these drawn polyester fibrils are too fine to be observed accurately with an optical microscope in cross sections of the filaments even when the nylon matrix is stained to heighten the contrast.
• the fibril diameters in the drawn yarn can be calculated as discussed under Definitions, Formulae, and Tests from the diameter of the polyester particles observed microscopically in the collected extrudate and length of the fibrils in the undrawn yarn, and can be measured in drawn filament cross-sections by electron microscope observation.
• the electron microsope measurements check the diameters calculated from particle size in the extrudate within about 10%.
• the lengths of the fibrils in the undrawn yarn can be measured microscopically, as noted under Definitions, Formulae, and Tests.
• the lengths of the fibrils in the drawn yarn are derivable by multiplying undrawn fibril length times draw ratio, as checked by electron microscope observation.
• the average lengths of the polyester fibrils in the X drawn yarn of this invention are in the range from 100 microns up to 500 microns or more.
• the extruder had screw diameter of one inch and depth of channel in the metering section of 0.031 inch.
• a throughput of about 1 to 5 pounds per hour was used through each spinneret.
• the spinnerets had 12, 20, or 24 holes each.
• spinning was like a full scale operation using an extruder having a 3% inch diameter screw and depth of channel in the metering section of 0.0938 inch.
• the throughput was generally 25.8 pounds of polymer per hour, for each 136 hole spinneret/quench stack combination. From one to four such spinnerets were fed by the one extruder in various runs.
• the residence time in the extruder and up to the spinneret was generally in the range of 4 to 10 minutes; and in the pilot plant the residence time in the extruder and up to the spinneret decreased from 8 to 2.5 minutes as the number of 136-hole spinnerets fed by the extruder increased from one to four.
• the quench stack used in the pilot plant runs of Table 1 below was as in Example 1 of Swanson et al. copending US. application Ser. No. 426,631 above cited, using a flow of cooling gas countercurrent to the filament travel upward from the gas inlet, and below the gas inlet a main flow of gas concurrent with the filament travel.
• the zone immediately below the spinneret was heated and the gas therein was maintained essentially quiescent. In this zone the temperature was about 3l0-390 C. at a point /2 inch below the spinneret and A inch outside the outermost ring of spinneret holes.
• the laboratory stack was a smaller version, without heating means.
• the take-up speed was 1,360 feet per minute for the standard throughput of 25.8 pounds per 136 holes.
• Undrawn denier was about 30-35 per filament. Birefringence of the undrawn yarn was in the range between 0.002 and 0.008.
• the yarn was drawn in accordance with known procedures, either for maximum strength as desired in industrial yarns; or for high strength, and high uniformity as indicated by freedom from dye streaks and bands, as desired in textile yarns.
• a heat relaxation or annealing step allowing about 5%17% contraction of the drawn yarn was generally used in producing the textile yarns of the tables below, operated to adjust shrinkage to the desired levels as known in the art.
• the solid polymers used after blending as chips, were dried by vacuum and heat in the blender to bring the moisture content below 0.02% by weight.
• the nylon ingredient contained a heat stabilizer, generally cupric chloride dihydrate at 50 parts per million of copper.
• the nylon ingredient contained titanium dioxide delustrant at 0.3% by weight and manganese dichloride tetrahydrate light stabilizer at 20 parts per million of manganese.
• the blending, transferring, and melting operations were conducted under a blanket of dry nitrogen (dew 14 point not above 40 C.) with oxygen content not above 10 parts per million.
• the properties attained at maximum draw are: UTS of at least 10 g./d.; toughness index of at least 40; initial tensile modulus of at least 60; flat spot index of at most 20; Goodyear tube fatigue endurance of at least 1,500 minutes; and for the hot wet yarn (in water at 95 C.) initial tensile modulus of at least 40 g./d. and UTS of at least 6 g./d.
• the preferred yarn products of the invention when drawn and processed for textile uses rather than for maximum tenacity, still attain high initial tensile modulus of at least 60 g./d. and high hot wet tensile modulus of at least 40 g./d. as for the high tenacity yarns.
• They have dye strength, compared to nylon-6 as 100, of at least 150 tested with Cl. Disperse Blue 3, and dyeing uniformity rating of Excellent.
• Their liveliness, measured by percent Work recovery is at least compared to about 50% for nylon-6.
• Example Number or Letter Operating Conditions Ex. 13(5) Ex. 0 Ex. D Ex. 8 Ex. 9 (Lab Polyester, Wt. Proportion (and Type) 1 30 (E3) 30 (E3) 30 (E3) 40 (E2) 20 (E 1) Nylon-6, Wt. Proportion (and Type) 70 (N2) 70 (N2) 70 (N2) 60 (N3) 80 (N4) Melt Viscosity of Blend at 275 C. (poises)..- 1, 500 1, 0 1, 500 ca. 1,600 ca. 1,900 Apparent Mixing Shear in Extruder (vel secr 78 Q7 7 8 150 150 Example Number or Letter Operating Conditions Ex. 13(5) Ex. C Ex. D Ex. 8 Ex. 9 (Lab Avg. Diam.
• Jet Velocity (it/min.) 2 7 51 51 85 105 Stack Draw Down Q 26. 5 26. 5 16 13 Example Number or Letter Spinning and Drawing Results on Yarns Drawn for Maximum Tenacity (6X, o maximum short of Ex- 1 Ex. 5 Ex. 6 Ex. 7 steeply increasing occurrence of breaks)
• Ex. A (Lab) Ex. 2 Ex. 3 Ex. 4 (Lab) (Lab) (Lab) (Lab) Drips per 1,000 pounds 1, 1 ca. 2 3 3 6 ca. 7 ca. 4 ca. 9
• Toughness Index (UTS x UE%) 39. 39. 40.4 41. 2 41. 5 38. 4 31. 5 40. 2 36. 0
• Rel. Visc. Relative Viscosity in aqueous 90% formic acid by ASTM Test D789-62T.
• N1, N2, N3, N4 terminator is sebacic acid; for N0, terminator is water.
• Ex. A shows data for spinning nylon-6 under commercial conditions, using 18 mil diameter spinneret capillaries; and for comparison using 13 mil diameter capillaries with the same hroughput (viz 25.8 lb./hr. for 136 holes).
• this figure applies to both sides of capillary; a single figure and a blank means the value was measured only for one of the capillary sizes and otherwise a figure is shown for each size capillary in the appropriate column. These yarns were drawn for maximum tenacity.
• Test Sequence (a) Infiate to 24 p.s.i. (abs) at ambient temperature;
• Polyester, Wt. Proportion (and Type) 1 30 (E3) 30 (E5) 33 (E6) 20 (E7) 30 (E8 Nylon Wt. Proportion (and Type) 2 100 (N2) 70 (N66) 70 (N2) 67 (N2) 80 (N2) 70 (N2) Apparent Mixing Shear in Extruder (velocity gra rent, se 70 110 110 110 130 120 Extruder, Rev. per min 40 65 65 65 65 77 70 Avg. Dlam. of Polyester Particles in Extrudate (microns) 1. s 1. 9 1. 9 1, 2 2. 2 Avg. Spinning Temp. C.)-Range *3 C 265 265 265 270 264 263 Apparent Spinneret Capillary Shear (1,000s see- 2. 6 5.
• N2 See Table A(-2), above.
• N 66 Commercial nylon-66 (polyhexamethylene adipamide).
• the seat belts from yarn of this invention have desirable level of elongation coupled with very high breaking strength and high retention of breaking strength after being flexed or abraded; and have at the same time excellent dyeability.
• Table II below illustrates, in Examples 14-18, yarns the variants of the polyester and nylon ingredients indicated in the table. As seen from the table, the yarn products of these examples showed improved properties over the nylon-6 control generally as for the yarns of Table I.
• polyester ingredient is predominantly polyethylene terephthalate and the nylon ingredient is predominantly poly-e-caproamide in weight proportions of 25-40 polyester per 100 parts combined polyester and nylon; and nylon has relative viscosity in aqueous 90% formic acid of about 40-65 by ASTM test -D789-62T and has not over about 10 m.eq. of primary amino groups per kg. of nylon and not over m.eq. of total end groups per kg. of nylon; which yarn as spun has a birefringence in the range between 0.002 and 0.008 and when drawn 5 X has at least 30,000 polyester fibrils per 1,000 sq. microns of transverse filament area; said fibrils having lengthzdiameter ratio of at least 2,500:1.

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• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
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• Textile Engineering (AREA)
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Citations (2)

• 1967
  • 1967-10-23 US US677064A patent/US3470686A/en not_active Expired - Lifetime
• 1968
  • 1968-10-22 CH CH1576868A patent/CH488823A/de not_active IP Right Cessation
  • 1968-10-22 NL NL6815092A patent/NL6815092A/xx unknown
  • 1968-10-22 GB GB50041/68A patent/GB1202650A/en not_active Expired
  • 1968-10-22 FR FR1589801D patent/FR1589801A/fr not_active Expired
  • 1968-10-22 DE DE19681804444 patent/DE1804444A1/de active Pending
  • 1968-10-22 BE BE722713D patent/BE722713A/xx unknown

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