US3517412A - Melt spinning process and apparatus - Google Patents

Melt spinning process and apparatus Download PDF

Info

Publication number
US3517412A
US3517412A US752414*A US75241468A US3517412A US 3517412 A US3517412 A US 3517412A US 75241468 A US75241468 A US 75241468A US 3517412 A US3517412 A US 3517412A
Authority
US
United States
Prior art keywords
spinning
shield
gas
spinneret
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US752414*A
Other languages
English (en)
Inventor
Eugene A Swanson
William H Harlacher
Grady N Dulin Jr
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Allied Corp
Original Assignee
Allied Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Allied Chemical Corp filed Critical Allied Chemical Corp
Priority to US752414*A priority Critical patent/US3517412A/en
Application granted granted Critical
Publication of US3517412A publication Critical patent/US3517412A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/08—Melt spinning methods
    • D01D5/084—Heating filaments, threads or the like, leaving the spinnerettes

Definitions

  • This invention relates to the melt spinning of e-polycaproamide compositions.
  • the invention is particularly useful for spinning polycaproamide at high speeds and for spinning polycaproamide of very high molecular weight and high melt viscosity into filaments for production of high strength yarns for use, e.g., in automobile tire. cords.
  • Typical applications include high strength webbing such as safety belts; protective coverings such as tarpaulins; netting; and reinforced structures such as tires, conveyor belt and power transmission belts.
  • improvements in strength are continually sought since such improvements increase the effectiveness of the yarn in a par ticular utilization, or permit the use of less yarn without sacrifice of strength of the overall structure.
  • a high rate of filament production which must start with a high rate of spinning, is very important economically.
  • This invention provides a process allowing the melt spinning of higher molecular weight polycaproamide than could be spun using the methods heretofore generally known, and allowing the spinning of polycaproamide filaments at higher rates than usually obtainable for a given polymer molecular weight.
  • the process of the present invention comprises extruding into a spinning chamber an e-polycaproamide melt which is at a temperature of about 250 C.-300 C. to form continuous filament therefrom downwardly through a spinneret and into a zone of the chamber immediately therebelow wherein the resulting filaments contact hot quiescent gas.
  • the temperature measured by a ther mocouple is at least 40 C. higher than the temperature of the polycaproamide melt which is being extruded, and is at least 315 C.; but is not above the temperature, of
  • temperatures immediately below the spinneret are maintained well above those which can safely be maintained in the molten extrudate itself without degrading it. While we do not intend to be bound by theories, we believe the successful use of temperatures of 315 C. and above in our process is connected with use of quiescent gas, and with volatilization from the polycaproamide filaments of low molecular weight constituents, especially lactam monomer, while the filaments contact this gas. The evolution of the monomer may create a protective influence on the filament against the effects of hot gas, and at the same time improve the spinnability of the melt, e.g., by providing a lubricating effect at the surface of the filaments being extruded.
  • a preferred temperature range /2 inch down from the spinneret is about 320 C.-380 C.; and the temperature should of course be no higher than that where polymer degradation sets in, viz. about 400 C. It will be appreciated that the extent of polymer degradation is a function of time of exposure to the hot gas as well as temperature, and that at relatively short exposure times the higher temperatures can be used.
  • the filaments after their contact with the hot quiescent gas and during their cooling, are passed in not over 2" of their travel from a zone at temperature equal to the melting point of the polycaproamide (about 210-220 C.) into a zone at temperature some 30 C. below the melting point of the polycaproamide.
  • the filaments are cooled rapidly from a temperature above the melting point of the polycaproamide to a temperature well below the melting point, with a beneficial effect on crystallinity and related properties.
  • That portion of the gas in the zones which are cooler than the molten extrudate can be in any state of motion which is nonturbulent; e.g., part of this gas can be quiescent like the hot gas, and another part can be in smooth flow cocnrrent, countercurrent, or across the filaments as generally known for quench gas flow in melt spinning processes. There will always be some gas moving out of the quiescent zone, which gas should be drawn out of the spinning chamber, to remove from the spinning chamber the volatilized lactam in this gas.
  • this gas will be Withdrawn in the upper section of the chamber, e.g., just below the quiescent Zone, and will be taken out through a heated pipe or the like, to avoid condensation of its lactam content in the spinning chamber or on the filaments when being cooled.
  • a spinning tower is divided into an upper section 20, a midsection 22, and a lower section 24.
  • the tower provides a spinning chamber the upper part of which is defined by a horizontal spinneret 14 having a multiplicity of orifices 16, and by vertical cylindrical shield 12 comprising sections 38 and 40 described below.
  • the upper section, 20, of the tower comprises said spinneret and shield, and outer wall sections 28 and 60 forming around shield 12 an outer chamber 30.
  • Chamber 30 is provided with exhaust ports or outlets 32 which lead to a vacuum pump or other suitable means, not shown, for withdrawing gas. These outlets 32 are jacketed for heating to prevent condensation of lactam therein.
  • Outer wall section 28 terminates below in an inwardly projecting lip 34, forming a bottom for outer chamber 30.
  • Outer wall section 60 is removably connected, e.g., by a liquid seal 62 or deformable gasket or packing, with wall section 28 and is terminated above by connection to spinneret 14, thus allowing ready disassembly of the tower for maintenance of the spinneret.
  • Shield 12 comprises upper section 38 and adjustable lower section 40.
  • Heating means are provided upon the upper section 38 for heating the uppermost region of spinning chamber 10, such means including suitably a band electric heater 44.
  • the upper and lower sections 38 and 40 of the heated shield are constructed of a heat conducting rust resistant alloy, preferably stainless steel.
  • the upper section is in tight physical contact with the lower section to transfer heat from the heated upper portion to the nonheated lower portion, thereby providing a thermal gradient from the end of the electric band heater 44 to the bottom of the lower section 40.
  • This upper section preferably closely surrounds the area immediately below the outermost spinneret orifices, being at a radial distance from those outermost orifices suitably about A inch-2 inches.
  • the lower section 40 of the heated shield is vertically adjustable by means of set screw 46 so that the vertical distance from the face of the spinneret 14 to the lower edge, 48, of section 40 may be adjusted as desired.
  • the preferred adjustment is about 3 inches to about 8 inches.
  • the heated shield must be sealed around the spinneret face to prevent air currents at the spinneret face sufficient to cause filament flicking at the spinneret opening which will depreciate the physical properties and increase variations in filament diameter.
  • the upper surface of section 38 of the heated shield is provided with a packing retainer 50 for receiving a circular gasket or packing 52 such as an O-ring; or other sealing means, constructed to withstand temperatures in excess of 400 C. can be used, e.g., a liquid seal.
  • Means are provided for urging the packing 52 into engagement with the face of the spinneret, comprising a series of pistons 54 attached to section 38 and received in cylinders 56, which cylinders contain compression 4 springs 58. Springs 58 bear against lip 34 to urge pistons 54 and wall section 38 upward.
  • lower wall section 42 extends downward forming the midsection 22 of the spinning chamber 10, down to gas inlets 26. Below inlets 26 walls 42 continue downward to form the lower section 24 of spinning chamber 10.
  • the total length of the spinning chamber will usually be about 10 feet in the apparatus of the drawing.
  • the heating element 44 is turned on and allowed to reach thermal equilibrium.
  • the lower section 40 of the heated sleeve or shield is adjusted with the set screw 46 to the desired vertical distance from the spinneret face to the lower edge 48 of the shield.
  • Molten polymer is pumped into the spinneret 14 from which it passes through the orifices 16 and drops as filaments in the spinning chamber 10.
  • the top of shield 12 is sealed against spinneret 14, thus separating the upper zone 20 of spinning chamber 10 from the outer surrounding chamber 30.
  • relatively cool gas suitably air
  • a minor portion of the air moves upwardly through midsection 22 toward the heated shield 13 while the remainder of the air moves downwardly through lower section 24 in the direction of travel of the filaments 18.
  • the air flow through inlet 26 is maintained at a rate suitably in the range of about 20 standard cubic feet per minute to about 160 standard cubic feet per minute for a 9-inch diameter tower.
  • One advantage provided by use of our heated shield and hot quiescent gas zone within the shield is that gas fiow rates into the the spinning chamber prove less critical than where such heated shield is not used.
  • outlets 32 are kept at temperatures of the order of about 300 to about 400 C. to avoid condensation of organic vapors therein, e.g., lactam.
  • the outlets are suitably at a level from just below the spinneret to about a foot below the lower edge 48 of the heated shield, a preferred location being within about 3 inches above or below the lowest setting of the lower edge 48 of shield 12.
  • the gas entering through inlets 26 can be maintained at any desired temperature which will generally be at least 30 C. below the polycaproamide melting point so as to effect the desired quick cooling of the filaments when their temperature is near the melting point.
  • the entering gas may be made to enter the chamber at uniform flow into the chamber throughout the entire periphery of the chamber, or the flow through inlets 25 can be adjusted so as to be unequal going around the periphery. In fact the gas can enter from only one inlet, with a gas outlet provided opposite thereto, to produce cross-flow quenching.
  • Gas distributing means such as grids, screens, cloths and the. like will advantageously cover inlets 26 to control the gas flow pattern.
  • the humidity of the entering gas can be established at any given desired humidity level, a suitable humidity range being from about 40 percent to about percent relative humidity at 28 C.
  • a low moisture content of the entering gas corresponding to vapor pressure of say about 10-100 mm. of mercury, may contribute to good properties in the final filaments.
  • a cooling temperature curve for the gas in the Spinning chamber, plotted against the distance from the spinneret face, is indicative of the mechanical and process parameters of the spinning system.
  • a typical cooling curve, characteristic of spinning when employing quiescent gas in the region near the spinneret but not heating this region above the temperature of the extruded melt, is
  • This cooling curve is a power function wherein the change in T is very small for the first two inches, but the change in T increases at accelerated rates from 2 to 5 inches, and increases with considerable acceleration at distances approaching the overall length of the heated shield, namely 5 to 8 inches.
  • This cooling curve is essentially the opposite of a normal nylon -6 cooling curve such as that described above, characteristic of melt extrusion performed without our heated shield.
  • yarns can be produced showing improvement in ultimate tensile strength of about 0.5 gram per denier and more, versus yarns spun in chambers operating at conventional temperatures; and this gain is without sacrifice of the other important physical properties of the yarn. Such improvement is of significant importance in the applications of high strength yarn. Moreover yarn spun in accordance with this invention shows improved performance upon drawing and windup over yarn spun using conventional temperatures in the spinning chamber.
  • the polycaproamide melt which is spun by the process of this invention can contain various dissolved or finely dispersed additives such as stabilizing agents, delustrants, pigments, blended-in polymers, latent cross-linking agents, adhesion-promoting agents, antistatic agents, etc.
  • thermoplastic polymers generally, to greater or lesser degree depending upon the extent to which they tend to build up volatile impurities during spinning, in particular impurities that deposit on the spinneret.
  • impurities include straight chain and cyclic low molecular weight oligomers and cyclic monomers from polyhexamethylene adipamide, polyenantamide, polyoctanamide, polynonanamide, polydecanamide, polyundecanamide, polydodecanamide, polyethylene terephthalate, polyethylene isophthalate and polyethylene 2,6 and 2,7 naphthalene dicar-boxylate.
  • the number average molecular weight is determined from the equation:
  • Amine and carboxyl groups are determined by direct titration in a suitable solvent.
  • Ultimate tensile strength All ultimate tensile strengths are measured on a Scott Tensilgraph lP-4 using Spruan'ce air-operated cord clamps and a gage length of 10 inches. A weight of 10 kilograms was used over carriage weight of 2 kilograms. Four breaks on each sample are taken, or more, so that four breaks fall within /2 inch on the load (vertical) scale. Reading vertically, record the breaks and calculate the average.
  • Ultimate elongation Toughness index is measured by the area under the stress-strain curve from the origin out to the breakpoint. It is a measure of the amount of work required to rupture the fiber and is an indication of relative durability under mechanical fatigue.
  • EXAMPLE 1 This example utilized polycaproamide of number average molecular weight 30,800 and relatively low melt viscosity prepared using sebacic acid to combine with amine groups as described in the copending US application of Ian C. Twilley, Ser. No. 426,632 filed Jan. 19, 1965, Example 1 thereof.
  • the polymer contained, as heat stabilizing agents, a trace amount of dissolved copper compound and a small amount of a ketone/diarylamine con- 7 densation product as in Jr U.S.P. 3,003,995 of Oct. 10, 1961.
  • a spinning apparatus as illustrated in the accompanying drawing and as hereinabove described was provided with an annular shield heated with a 1,000-watt electric band heater around its upper surface, the shield being sealed by gaskets against the spinneret.
  • Each hole of the 136-hole spinneret was of 0.013 inch diameter.
  • the shield was adiusted to total length of 6.01 inches. Its internal diameter was 9.25 inches.
  • the length of the quiescent region thus created in this spinning apparatus was six inches; the length of the countercurrent flow region was seven feet; and the length of the cocurrent region was ten feet.
  • the inner diameter of the tower was about 9 inches, which was about inch greater than the diameter of the outermost ring of orifices in the spinneret.
  • Air at 28 C. and relative humidity, at 28 C., of 65% was admitted through inlet means 26 at a rate of 63 cubic feet per minute. Six cubic feet per minute of gas was re moved through exhaust ports 32. The cooled extrudate was wound up as undrawn multifilament yarn at a rate of 1500 feet per minute. The undrawn yarn was subsequently drawn to a draw ratio of about 4.9 employing conventional drawing and yarn heating means.
  • Tire yarn produced using the annular heated shield of this invention was compared with tire yarn produced from the same apparatus but without the shield.
  • Table II summarizes the results obtained, and shows significant improvement in yarn strength and toughness and in performance upon drawing and winding when using the process of this invention, in which a heated annular shield is employed, versus operation without the heated shield.
  • Table III shows the results of spinning a sebacic acid terminated polymer with a lower number average molecular weight than that used in Example 1, and with the procedure and conditions of Example 1 except that the length of the heated annular shield used was 5 inches. Data tabulated in Table III represents an average of 6 spinning trials with 5 different polycaproamide polymers. It will be appreciated that in Table III, as in Table II, higher strength, tougher yarn was produced and better performance in drawing was obtained when using the heated shield than without it.
  • EXAMPLE 3 A polycaproamide spinning polymer, having a normal number average molecular weight for spinning, viz about 20,000 molecular weight, and a normal melt viscosity for its molecular weight was used in this example. The polymer was spun using the process and apparatus described in Example 1, and shown in the drawing of this application. The length of the heated annular shield was 610 inches.
  • Table V summarizes the results of tests conducted with and without a heated shield.
  • a spinning tower comprising a horizontal spinneret with at least one vertical orifice therein; sealed around said spinneret and closely surrounding the area immediately below the outermost orifices thereof, a downwardly extending shield open at its lower end and provided, at least at its upper end, with heating means; a chamber outside said shield and in communication with the exterior References Cited UNITED STATES PATENTS 2,335,122 12/ 1943 Dreyfus. 3,053,611 9/1962 Griehl. 3,299,469 1/1967 Charlton.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
  • Artificial Filaments (AREA)
US752414*A 1965-01-19 1968-06-18 Melt spinning process and apparatus Expired - Lifetime US3517412A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US752414*A US3517412A (en) 1965-01-19 1968-06-18 Melt spinning process and apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US42663165A 1965-01-19 1965-01-19
US752414*A US3517412A (en) 1965-01-19 1968-06-18 Melt spinning process and apparatus

Publications (1)

Publication Number Publication Date
US3517412A true US3517412A (en) 1970-06-30

Family

ID=23691585

Family Applications (1)

Application Number Title Priority Date Filing Date
US752414*A Expired - Lifetime US3517412A (en) 1965-01-19 1968-06-18 Melt spinning process and apparatus

Country Status (8)

Country Link
US (1) US3517412A (it)
BE (1) BE675294A (it)
CH (1) CH448370A (it)
DE (1) DE1660154A1 (it)
ES (2) ES321937A1 (it)
FR (1) FR1463735A (it)
GB (1) GB1117946A (it)
NL (1) NL6600663A (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4732720A (en) * 1981-02-26 1988-03-22 Asahi Kasei Kogyo Kabushiki Kaisha Process for the production of uniformly dyeable nylon 66 fiber
US5700490A (en) * 1994-09-30 1997-12-23 Barmag Ag Apparatus and method for the thermal treatment of fibers
US5702730A (en) * 1995-05-26 1997-12-30 Reifenhauser Gmbh & Co. Maschinenfabrik Apparatus for making a continuous thermoplastic fleece
CN114262945A (zh) * 2021-12-30 2022-04-01 长乐恒申合纤科技有限公司 一种母丝单孔单板生产方法
CN114293269A (zh) * 2022-01-05 2022-04-08 新乡市新科防护科技有限公司 一种多层阻燃特种服装面料预混固化工艺

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3406347A1 (de) * 1983-02-25 1984-10-11 Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid Spinnanlage fuer chemiefasern mit anblaskasten und spinnschacht
CN112695391B (zh) * 2020-12-22 2021-09-07 江苏德力化纤有限公司 一种高均匀性超细聚酯纤维生产设备及制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2335122A (en) * 1943-11-23 Ticket issue counting mechanism for
GB852351A (en) * 1956-05-18 1960-10-26 Snia Viscosa Improvements in or relating to processes and apparatus for melt-spinning of synthetic linear polyamides
US3053611A (en) * 1958-01-21 1962-09-11 Inventa Ag Process for spinning of synthetic fibers
US3299469A (en) * 1964-11-18 1967-01-24 Du Pont Melt-spinning apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2335122A (en) * 1943-11-23 Ticket issue counting mechanism for
GB852351A (en) * 1956-05-18 1960-10-26 Snia Viscosa Improvements in or relating to processes and apparatus for melt-spinning of synthetic linear polyamides
US3053611A (en) * 1958-01-21 1962-09-11 Inventa Ag Process for spinning of synthetic fibers
US3299469A (en) * 1964-11-18 1967-01-24 Du Pont Melt-spinning apparatus

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4732720A (en) * 1981-02-26 1988-03-22 Asahi Kasei Kogyo Kabushiki Kaisha Process for the production of uniformly dyeable nylon 66 fiber
US5700490A (en) * 1994-09-30 1997-12-23 Barmag Ag Apparatus and method for the thermal treatment of fibers
US5702730A (en) * 1995-05-26 1997-12-30 Reifenhauser Gmbh & Co. Maschinenfabrik Apparatus for making a continuous thermoplastic fleece
CN114262945A (zh) * 2021-12-30 2022-04-01 长乐恒申合纤科技有限公司 一种母丝单孔单板生产方法
CN114293269A (zh) * 2022-01-05 2022-04-08 新乡市新科防护科技有限公司 一种多层阻燃特种服装面料预混固化工艺
CN114293269B (zh) * 2022-01-05 2022-11-01 尚军 一种多层阻燃特种服装面料预混固化工艺

Also Published As

Publication number Publication date
CH448370A (de) 1967-12-15
NL6600663A (it) 1966-07-20
BE675294A (it) 1966-05-16
ES321937A1 (es) 1966-10-16
ES325047A1 (es) 1967-08-16
FR1463735A (fr) 1966-12-23
GB1117946A (en) 1968-06-26
DE1660154A1 (de) 1971-03-11

Similar Documents

Publication Publication Date Title
US3227793A (en) Spinning of a poly(polymethylene) terephthalamide
US3118012A (en) Melt spinning process
US3361859A (en) Melt-spinning process
US3437725A (en) Melt spinning apparatus and method
US4702876A (en) Variable-aperture process for the manufacture of filaments from aromatic polyamides
US3111368A (en) Process for preparing spandex filaments
US3907957A (en) Quenching process for melt extruded filaments
US2293388A (en) Polyamides and their preparation
US3517412A (en) Melt spinning process and apparatus
US2335922A (en) Manufacture of artificial textile materials and the like
EP0535082B1 (en) Fiber-forming copolyamide and fibers produced therefrom
US3936253A (en) Apparatus for melt-spinning synthetic fibers
US3457341A (en) Process for spinning mixed filaments
US2904536A (en) Polyamide containing interlinear piperazine units
US4045534A (en) Process for melt-spinning synthetic fibers
US3047541A (en) Process for the continuous production of polyamide fibers and ribbons
US5238740A (en) Drawn polyester yarn having a high tenacity and high modulus and a low shrinkage
US2364387A (en) Production of polymer
EP0456505B1 (en) Apparatus for spinning synthetic melt spinnable polymers
US2935372A (en) Process of producing shaped bodies by combining reactive intermediates, at least one of which intermediates is in the vapor phase
GB1580104A (en) Spinning and stretching of filament cables
US3216965A (en) Blend of a polyterephthalamide and a lower melting polyamide for improved dye receptivity
AU643641B2 (en) A spinning process for producing high strength, high modulus, low shrinkage synthetic yarns
US3345445A (en) Melt spinning process of polyamides
US3271818A (en) Quenching apparatus