Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
  • C08G69/36—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino acids, polyamines and polycarboxylic acids
• • 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
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/12—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyamide as constituent
• • 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
  • Y10S57/905—Bicomponent material
• • 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
  • Y10T428/2929—Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
  • Y10T428/2931—Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]

Definitions

• This invention relates to composite filaments and particularly to improved composite filaments prepared from synthetic linear polyamides.
• Composite filaments which are particularly suitable for the production of stretch hosiery were disclosed by Olson in US. Pat. No. 3,399,108. These filaments have the ability to crimp under restraint and this leads to distortion of the stitches in the hosiery fabric so that the fabric has more ability to stretch than a conventional hosiery fabric. Although these composite filaments-have produced good stretch hose, further improvements in crimpability under fabric restraint are desirable, particularly in the production of miniature stretch hose. In this connection, the current wide-spread use of pantyhose also makes improvement in the crimpability of multifilament welttype yarns very desirable. in addition, improvement in filament strength is desirable in order to enhance the durability of hosiery leg yams;
• a crimpable composite filament having a crimp elongation, when subjected to steam at 100.
• the copolyamide is characterized by an amide group frequency of 8440-8725 equivalents/10 grams and a differential thennal analysis (DTA) melting point of 210-225 C.
• DTA differential thennal analysis
• the homopolyamide ispo1y(hexamethylene adipamide) i.e., 6- -6 nylon, or poly(epsilon-caprolactam), i.e., 6 nylon; and the copolyamide is a copolymer consisting essentially of 70-82 percent by weight of 6-6 nylon polymer units, 1 3-25 percent by weight of 6 nylon polymer units and 5-17 percent by weight of hexamethylene dodecanedioamide (6-12 nylon) polymer units.
• the crimp diameter i.e., the average diameter of the helices formed when the filament is subjected to steam at 100 C. under a load of 1.2 mgd, is preferably less than 6 mils and most desirably in the range of 3-5 mils.
• the copolymer employed should contain at least 70 percent by weight of 6-6 polymer units to provide a high level of strength and durability in hose.
• the other components of the copolymer should be selected to give a DTA melting point no greater than 225 C. so that the copolymer component of the as-drawn filament will have adequate shrinkage to produce high levels of crimp.
• the DTA melting point should be at least 210C. to provide adequate shrinkage tension for crimp formation under restraint and to insure a high tenacity.
• amide group frequency should be in the range of 8440-8725 equivalents] 10' gms. of polymer since lower levels lead to inadequate crimpability and higher levels lead to undesirable moisture sensitivity and loss of fit athigh humidity.
• the filaments of this invention are prepared by extruding the homopolyamide and copolyamide in either a side-by-side or a sheath-core relationship to form a filament (or two or more filaments as a yam), quenching and drawing the filament in the conventional manner, passing the drawn filament through a heating zone under low tension to develop crimp and thereafter stretching the filament to remove crimp.
• the crimped filament should be pennitted to cool before crimp is removed.
• the temperature in the heating zone should be at least C. to give the desired crimp characteristics. The temperature required will, of course, dependon the length of the heating zone and the speed of the filament passing through the zone.
• the preferred technique for reducing tension in the heating zone and then removing crimp is by passage of the precrimped filament over a series of snubbing pins in its advance away from the draw roll, a suitable heating means such as an air jet being interposed between the draw roll and snubbing pins, as shown, for example, in FIGS. 1 and 4 of the Olson patent. From the snubbing pins, the filament passes around a powerdriven roll, rotating at a lower peripheral speedthan the draw roll to permit the filament to retract between 'the rolls.
• the homopolyamide is preferably extruded as the sheath to facilitate quenching of the filaments.
• Use of the copolyamide as a sheath results in slower quenching and can lead to filament sticking at high spinning speeds.
• the two components are usually present in approximately equal amounts by weight of the filamentsghowever, the ratio may be varied as required to achieve the desired properties.
• the ratio may be varied as required to achieve the desired properties.
• sheath-core filaments it may be desirable to employ a somewhat larger percentage of the higher shrinkage component in the core.
• the core should be highly eccentric in order to develop the required retractive force on crimping. This means that part of the sheath will be very thin, i.e., the minimum thickness of the sheath will range from 5 percent of the filament diameter to 0. l percent or less.
• Either or both of the components may contain any of the various additives commonly employed in the production of fibers, such as delusterants, pigments, dyes, antioxidants, antistatic agents and surface-modifying agents.
• hosiery filaments are usually of round cross section, other shapes may be employed and may be particularly useful in certain end uses such as in tricot knit fabrics or certain woven fabrics.
• cross sections of trilobal shape, shield shape, heart shape, cruciform shape and various multilobal configurations may be employed.
• the filaments and yarns of this invention possess an unusually good balance of desirable crimp characteristics, high strength and low shrinkage in the fabric. While certain copolymer compositions outside the-limits of this invention may be processed to give almost equivalent crimp characteristics, this is accomplished only at the expense of a loss in strength, particularly afier boil-off as in a finished hose.
• the filaments of this invention have the desirable characteristic of being essentially straight when removed from the package but tend todevelop crimp readily afterknitting due to the mechanical working of the filament inthe knitting machine. This results in a reduction in area of the greige fabric and, as a consequence, fewer picks develop in the hose during mill handling. Picks are flaws in the stitch construction and may be slight distortions of the stitch which can be corrected by pulling a wale or course or they may be severe distortions which are more difficult to repair.
• the shrinkage of the filaments of this invention is substantially lower than that of prior art bicomponent hosiery filaments. Shrinkages below 4' percent are readily achieved. This permits the knitting of a tighter fabric which is less subject to picking and is appreciably more economical in terms of yarn required to provide any given size of hose.
• relative viscosity signifies the ratio of flow time in a viscometer of a polymer solution containing 8.2 percent by weight of polymer, relative to the flow time of the solvent by itself. Measurements of relative viscosity are made with 5.5 grams of polyamide in 50 milliliters of 90 percent by weight formic acid at 25 C.
• Shrinkage and crimp elongation of the filament are determined as follows:
• a 750 denier skein of monofil or multifilarnent yarn is prepared by winding the requisite number of turns on a reel to give a skein of about 55 centimeters length when suspended with a weight attached.
• the denier of the filament bundle representing the collapsed skein will, of course, be twice that of the original skein, i.e., 1,500 denier.
• the skein is hung on a hook with a 500 gm. weight suspended from its other end. After one minute, the length (a) of the skein is measured.
• the 500 gm. load is removed and a 1.8 gm. load is applied in its place so that the skein is under a tensile load of 1.2 mg./den.
• the polymer sample may be in the form of flakes, chips, fiber or film. In the following examples, the polymer samples were in the form of flakes or fiber. Using the instructions provided with the commercial Du Pont instrument, the conditions used to make the measurements are as follows:
• EXAMPLE I evaporator is charged with an aqueous solution containing 257 pounds 1 16.6 kg.) of hexamethylenediammonium dodecan edioate (6-12 nylon salt), 2034 pounds (922.6 kg.) of hexamethylenediammonium adipate (6-6 nylon salt) and 338 pounds (153.3 kg.) of epsilon caprolactam, and the resulting solution is heated at 34.7 psig (3.4 atmospheres) until the temperature reaches 146 C., giving a salt concentration of approximately 76 percent. The solution is then transferred to an autoclave, heated to a temperature of about 205 C. and brought to a pressure of 250 psig l8 atmospheres).
• the copolymer consisting by weight of 75 percent polyhexamethylene adipamide, 15 percent polyepsilon caproamide and 10 percent polyhexamethylene dodecanedioamide, has a relative viscosity of 46.
• Polyhexamethylene adipamide (6-6 nylon) flake having a relative viscosity of 46.5 is prepared in the conventional manner.
• the two flakes (6-6 and 6-6/6/6-12) are first conditioned by exposure to humidified nitrogen at l25 C. and 145 C., respectively, and then melted and pumped to a spinneret assembly of the type shown in FIG. 3 of 11.8. Pat. No. 3,399,108 to Olson, with holes arranged to spin three filament yarns.
• 'lhe relative viscosity of the 6-6 polymer after conditioning is 50 and that of the 6-6/6/6-l2 copolymer flake is 56.
• the two polymers are extruded, with the copolymer a the core to form eccentric sheath-core three-filament hosiery yarns containing 58 percent of the random copolymer and 42 percent by weight of the homopolymer.
• the sheath at its thinnest point, has a thickness equivalent to about 1 percent of the total filament diameter.
• the clearance between the projection and plate 1420f Olson is 0.003 inch (0.076 mm.).
• filaments are set by quenching, using a 60 inch (152 cm.) chimney and an air temperature of 60 C., steam conditioned as described by Babcock in U.S. Pat. No. 2,289,860 and wound into a package at 546 ypm.
• the yarn is subsequently withdrawn from the package and drawn at a ratio of 4.47 over an unheated draw pin situated between feed and draw rolls to give a final denier of 23-24 (nominally 20-3). It is then passed from the draw roll at 5 84 yprn (5 33 meters/min.) through a 3- inch long (7.6 cm.) tubular crimping chamber of the type shown in FIG. 5 of the Olson patent.
• the yarn is heated by passing 1.05 cubic feet/minute (0.03 cu. meter/min.) of 278 C. air through the chamber to give an air temperature of 188 C. at the exit.
• the yarn is then passed over two snubbing pins, the total yarn contact with the pins being 390, then to a withdrawal roll and finally to a winding device.
• the snubbing pins act to reduce the speed of the yarn in the heating zone so that the components can shrink differentially and the filaments can crimp under the influence of the heat.
• the yarn is stretched sufficiently between the pins and the withdrawal roll to remove most of the crimp. Between the draw and withdrawal rolls, the yarn is permitted to retract by 40 percent of its as-drawn length.
• the crimpable yarn When the crimpable yarn is exposed to hot water or steam, it crimps again in a very uniform fashion, and the crimp diameter and crimp elongation are quite uniform.
• the crimp elongation at a load of 1.2 mgd, determined as described previously, is 38 percent in atmospheric steam.
• the average crimp spacing and diameter are about 22 mils (0.56 mm.) and 4.6 mils (0.12 mm.), respectively.
• the shrinkage of the yarn is 1.6 percent.
• the tenacity of yarn removed from finished hose is 4.2 gpd.
• EXAMPLE II 20 denier, three-filament yarn with a crimp elongation of 40 percent, prepared substantially as described in Example I, was used as the leg yarn in conventional knitting of womens hose.
• otherwise identical hose were knit from 20 denier, three filament yarn prepared from the composition described below in the last paragraph of Example III. It was observed that greige hose from the yarn of this invention were substantially smaller than the comparison hose after removal from the knitting machine due to a tendency for the filaments to crimp at this stage. This reduction in size leads to a reduction in picks during subsequent handling of the hose in the mill.
• the'average over-all length of the unboarded hose was approximately 19 inches (48 cm.), and the length of the leg portion was approximately 15 inches (38 cm.
• the average over-all length of the comparison hose with tumble steaming was about 21 inches (60 cm.), and the leg length was 17 (50 cm.) inches.
• EXAMPLE Ill A copolymer flake containing 75 percent by weight of hexamethylene adipamide polymer units, 15 percent epsilon caproamide units and 10 percent hexamethylene dodecanedioamide units and having a relative viscosity of 55 .9 is prepared following the general procedure of Example I.
• the copolymer flake and 66 nylon polymer flake having a relative viscosity of 50.1 are extruded from a spinneret of the type identified in Example 1 to form a sheath-core filament with the copolymer as the core and having a final denier of about 15.
• the monofil consisting of about 60 percent core and 40 percent sheath by weight, is air-quenched and wound into a package.
• the filament is then removed from the package and drawn at a ratio of 5.02 over an unheated pin at a draw roll peripheral speed of 850 yds./min. (776 nieters/minute). From the draw roll, the filament is passed upwardly through a tubular crimping chamber of the type shown in FIG.
• Filaments designated A and B in Table l are prepared with different amounts of snubbing. Withdrawal roll speed is somewhat higher for filament B, as' indicated by the lower extent of retraction.
• the cumulative snubbing angle i.e., the sum of the angles of contact with the individual pins, is reported in Table l. Crimp characteristics and tensile properties of the filaments are also reported in Table 1. i
• filaments are prepared substantially as was filament B except that the core is a copolymer prepared substantially as in Example VIII of Olson by combining a 49.5 percent by weight 6-6 salt solution containing 1,362 lbs. of dry salt, a 26 percent by weight 6-12 salt solution containing 486 lbs. of dry salt and a 31 percent by weight 6-10 salt solution prepared with technical grade sebacic acid and containing 833 lbs. of dry salt.
• the draw ratio is adjusted to give approximately the same elongation at breakas the filaments of this invention.
• the air temperature at the crimping chamber is also slightly lower since this temperature was more nearly optimum for polymer composition.
• These filaments are designated C and D in the following table.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Proteomics, Peptides & Aminoacids (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Artificial Filaments (AREA)

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Family Applications (1)

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Cited By (7)

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Citations (5)

• 1970
  • 1970-05-01 US US33955A patent/US3667207A/en not_active Expired - Lifetime
• 1971
  • 1971-04-05 CA CA109,659A patent/CA941572A/en not_active Expired
  • 1971-04-14 IT IT23165/71A patent/IT943573B/it active
  • 1971-04-20 DE DE19712119097 patent/DE2119097A1/de active Pending
  • 1971-04-27 GB GB1168471*[A patent/GB1304504A/en not_active Expired
  • 1971-04-28 BE BE766402A patent/BE766402A/xx unknown
  • 1971-04-28 CH CH624071A patent/CH517191A/de not_active IP Right Cessation
  • 1971-04-29 NL NL7105923A patent/NL7105923A/xx unknown
  • 1971-04-30 FR FR7115612A patent/FR2091011A5/fr not_active Expired

Patent Citations (5)

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