US2571975A - Melt spinning process - Google Patents

Melt spinning process Download PDF

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Publication number
US2571975A
US2571975A US747252A US74725247A US2571975A US 2571975 A US2571975 A US 2571975A US 747252 A US747252 A US 747252A US 74725247 A US74725247 A US 74725247A US 2571975 A US2571975 A US 2571975A
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US
United States
Prior art keywords
polyamide
steam
pressure
spinning
melt
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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
US747252A
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English (en)
Inventor
Waltz Joseph Elmer
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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 EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US747252A priority Critical patent/US2571975A/en
Priority to GB9948/48A priority patent/GB653757A/en
Priority to FR974855D priority patent/FR974855A/fr
Priority to CH273680D priority patent/CH273680A/fr
Priority to BE486151A priority patent/BE486151A/fr
Priority to DEP28744D priority patent/DE826615C/de
Application granted granted Critical
Publication of US2571975A publication Critical patent/US2571975A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • D01D1/00—Treatment of filament-forming or like material
    • D01D1/04—Melting filament-forming substances
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B13/00—Conditioning or physical treatment of the material to be shaped
    • B29B13/02—Conditioning or physical treatment of the material to be shaped by heating
    • B29B13/022—Melting the material to be shaped
    • 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
    • D01D1/00—Treatment of filament-forming or like material
    • D01D1/06—Feeding liquid to the spinning head
    • D01D1/09—Control of pressure, temperature or feeding rate

Definitions

  • This invention relates to, the spinning of nylon yarn and more particularly to the production of yarn of uniform properties by spinning the yarn by a process which controls the troublesome depolymerization of the polymer which occurs at spinning temperatures.
  • nylon is a synthetic linear condensation polyamide formed by the condensation of suitable monomers or low molecular Weight polymers with the elimination of water. Consequently, water is normally present in the flake prior to spinning, the water being either a portion of that formed during polymer production or an amount absorbed from the surrounding atmosphere. It is well-known that at elevated temperatures the degree of depolymerization of polyamides is a function of the amount of Water present. To avoid excessive degradation by water steps are usually taken to dry the polymer flake to a low and controlled moisture content prior to the melt spinning step. In addition to using flake containing only small amounts of free moisture, steps may be taken to sweep away some of the water present during spinning by conductin the spinning in a moving atmosphere of very dry nitrogen or other suitable gas.
  • a further object is the provision of means for controlling the polymerization-depolymerization equilibrium.
  • a still further object is the provision of a process by which yarn having very good uniformity may be obtained without the use of costly materials such as highly purified nitrogen or a simiv lar gas.
  • the polymer is fed into the melt spinner through the polymer flake supply duct In.
  • the flake passes down through the open hopper I I into a preheater [2.
  • This preheater is heated in any convenient way, as, for example, by means of a steam jacket l3. Steam is passed into the heated jacket at I [and is passed to the trap at the bottom of the heater at point l5. At point I 6 a portion of the steam is removed and is sent through the bypass I! in which is located a valve l8.
  • the flake after being preheated passes downward to point l9 at which'it comes into contact with the steam passing through valve l8.
  • the steam delivered to the preheater jacket !3 is preferably high pressure steam (10- pounds per square inch) and thereby provides a temperature of the order of to C.
  • the steam that passed through valve I8 is at atmospheric pressure at point 19 since the hopper l Lis open to the atmosphere. Operation in this manner provides an automatic control of steam pressure and it is possible to keep the pressure in the melt spinner within very narrow limits.
  • the polymer melt is in equilibrium with steam and, accordingly, the viscosity of the melt is uniformly controlled.
  • the steam introduced into the flake at point l9 passes up through the polymer flake and out into the air at point 20. Thus, the steam serves to blanket the polymer and to adjust .the viscosity of the melt in relation to the water vapor pressure of the steam.
  • the flake After mixing with the steam, the flake passes to a grid melter 2
  • the polymer becomes thoroughly melted and forms a melt pool 22.
  • Polymer is then metered out through the pump 23 which passes the melt in fixed and constant amount to the spinneret assembly 24.
  • the inventory of polymer in the melt 22 is kept as small as possible in order to prevent decomposition. It is, however, preferred to keep an amount sufficiently large enough so that the polymer after melting stands exposed to the steam for a minimum of about 15 minutes before being metered out. This exposure permits establishment of an equilibrium.
  • the amount of water in the melt ranges from 0.11% to 0.18% even under the most rigid control. Further, the water vapor pressure varies from 550 mm. to 850 mm. of Hg. This variation results in yarn non-uniformities as mentioned above.
  • the process of this invention it has been found possible to maintain a constant amount (0.16% for polyheXamethylene adipainide) of moisture in the melt, and a more constant pressure (710- 7'70 mm. of Hg) in the cell. This constancy in moisture content results in an accurately controlled polymerization-depolymerization equilibrium and the spun polymer has physical properties which are much more uniform than comparable polymer spun by the conventional nitrogen processes.
  • the amount of water in the melt will depend, among other 'factorsup'on the polyamide being spun. Thus, while the amount is 0.16% for polyhexamethylene adipamide, the figure for other during spinning and does not vary between certain limits prevailing when the particular polyami'de is melt spun by conventional processes.
  • the pressure in the spinning unit will depend, in part, upon its location or; in other words, the local atmospheric. conditions. In general, the maximum fluctuations will be :30 mm. of Hg. The main point is that the pressure in the spinning unit during spinning by the process of this invention will be very nearly equal to the atmospheric pressure. Since the atmospheric pressure at a given location generally fluctuates only :30 mm. of Hg, the pressures in the spinning cells will be substantially constant. As pointed out above, by the process of this invention the fluctuation in pressure within the cell is advantageously maintained within narrow limits.
  • polyhexamethylene adipamide after spinning showed for the yarn spun by the process of this invention a relative viscosity of 26.0 (8.4% solution of polymer in formic acid) with an overall standard deviation of only 0.53.
  • Comparable polymer spun by the conventional spinning methods had a similar average relative viscosity (27.7) but a much higher overall standard deviation of 1.04. This shows that the polymer spun by the process of this invention had a more uniform molecular weight than the polymer resulting after spinning by the standard spinning method using nitrogen as the atmosphere over the melt pool.
  • the yarns of this invention had greater uniformity in elongations.
  • the average elongation figures for the yarn spun by the process of this invention was 24.0% as compared to an average elongation of 22.1% for yarn spun is a similar manner by the conventional process.
  • the average standard deviations for the two yarns, however, were 2.28 and 2.42, respectively, showing the greater uniformity in this respect of the yarns of this invention.
  • the process of this invention produces a yarn having physical and chemical properties the uniformity of which permits the use of acid-dyes, the dyed products being equivalent in uniformity to commercial nitrogen-spun yarns dyed with acetate dyes.
  • the commercial use of acid-dyes is desirable since a greater variety of dyed products may be produced through the use of this additional class of dye-stuffs.
  • steam at higher pressure may be used.
  • the steam pressure may be as high as 30 pounds per square inch gauge but generally it is preferred to use steam pressure within the limits of 7 to 10 pounds per square inch gauge.
  • the maximum steam pressure which can be used is dependent upon factors such as the nature of the polyamide being spun, and the type of yarn being formed. In general, the higher the steam pressure the higher is the amount of water in the melt in equilibrium with the steam.
  • the steam when used at atmospheric pressure does not tend to keep steam and gases of decomposition dissolved in the polymer to the extent that steam under pressure does.
  • a free flowing, controlled volume of steam passing over the melted polymer and through the flakes in the preheater provides a satisfactory means for eliminating occluded air.
  • polytetramethylene-adipamide polytetramethylenesebacamide.
  • polypentamethyleneadipamide polypentamethylenesebacamide
  • polyhexamethylene adipamide polyhexamethylenesebacamide
  • polyhexamethyleneglutaramide polyoctamethyleneadipamide
  • poly p xylylenesebacamide and the polyamide derived from 3,3 diaminodipropyl ether and adipic acid.
  • Polymerized epsilon-amino-caproic acid, polymerized Q-aminononanoic acid, and polymerized ll-amino-undecanoic acid are examples of linear polymers, derived from amino acids, which may also be used. Further, copolyamides or interpolyamides and any mixtures of polyamides :may be spun, by the process of this invention to form yarns of high quality.
  • any polyamide, which includes the polyesteramides may be used, such as are described in U. S. 2,071,250, U. S. 2,071,253, U. S. 2,130,523, U. S. 2,130,948 and U. S. 2,190,770. While a specific melt spinner has been described this invention is not limited thereby and any equivalent or similar device may be used.
  • the process is freed of many problems of equipment, design construction and operation. It is also freed from the required maintenance of feeding locks and storage locks and the repeated purging of them in order to remove air.
  • the operation of this invention does not require care fully predried flake nor large volumes of purified gas as an inert atmosphere.
  • the criticalness which the standard methods for spinning under nitrogen required is eliminated by the process of this invention. It is much easier to control the water vapor pressure in the process of this invention which involves the use of only one gaseous material (steam) than in the conventional processes which involve the use of two gases (water vapor and nitrogen).
  • yarn of the greater uniformity is produced in a practicable manner and with a. reasonable requirement of criticalness.
  • a process for spinning a synthetic linear polyamide which comprises melting the said polyamide in a chamber; introducing water vapor into said chamber at a substantially atmospheric pressure; exposing the resultant melted polyamide to the said water vapor until water is uniformly distributed in the melt; and feeding the resultant molten composition to a means for extruding it from said chamber, the melting and the feeding being carried out at substantially atmospheric pressure and in the presence of Water vapor at substantially constant pressure.
  • a process for spinning a synthetic linear polyamide which comprises melting the said polyamide in a chamber; introducing water vapor into said chamber at substantially atmospheric within the scope of the pressure; exposing the resultant melted polyamide to the said water vapor until water is uniformly distributed in the melt; and feeding the resultant molten composition to a means for extruding it from said chamber, the melting and feeding being carried out at substantially atmospheric pressure at a substantially constant vapor pressure of water and the said molten composition having a substantially constant moisture content prior to extrusion.
  • linear polyamide the steps comprising melting said polyamide in a chamber; introducing into said chamber water vapor at substantially atmospheric pressure; exposing the resultant melted polyamide to the said water vapor until Water is uniformly distributed in the melt; and feeding the said polyamide to a means for extruding it from the said chamber, said melting and feeding being carried out at substantially atmospheric pressure and in the presence of a substantially constant vapor pressure of water.
  • steps comprising melting said polyamide in the presence of a Water vapor at substantially atmospheric pressure, said vapor being introduced into said chamber; exposing the resultant molten composition to said vapor until water is uniformly distributed in the said molten composition; and feeding the said molten composition to a means for extruding it from said chamber, the said steps being carried out at substantially atmospheric pressure.
  • a process for spinning a synthetic linear polyamide which comprises melting said polyamide in a chamber; introducing water vapor at substantially atmospheric pressure chamber; exposing said polyamide to said vapor which isin the form of steam substantially at atmospheric pressure; allowing the resultant .molten composition to come into equilibrium with said water vapor so that water is uniformly distributed in said molten composition; and feeding said molten composition at substantially atmospheric pressure and in the presence of said water vapor to a means for extruding it from into said of said vapor to a means for extruding it from said chamber.
  • a process for maintaining the rate of polymerization and rate of depolymerization at equilibrium in a molten synthetic linear polyamide which comprises heating, at substantially atmospheric pressure, said polyamide in an atmosphere consisting of water vapor at substantially atmospheric pressure until water is uniformly distributed in said polyamide.
  • polyamide is polyhexamethyleneadipamide.
  • polyamide is polyhexamethylenesebacamide.
  • a process for spinning a synthetic linear polyamide which comprises melting the said polyamide in a chamber the atmosphere of which consists of water vapor; introducing the water vapor into said chamber at a substantially constant pressure of up to 10 pounds per square inch gauge; exposing the molten polyamide to said water vapor until water is uniformly distributed throughout the molten polyamide; and feeding the resultant molten composition to a means for extruding it from said chamber, the said melting and the said feeding being carried out in the said atmosphere consisting of said water vapor.
  • a process for keeping the rate of polymerization occurring in a molten synthetic linear polyamide equal to the rate of depolymerization occurring in said polyamide which comprises heating said polyamide in an atmosphere consisting of Water vapor at a pressure of up to 10 pounds per square inch gauge until water is uniformly distributed throughout said polyamide.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Artificial Filaments (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
  • Polyamides (AREA)
US747252A 1947-05-10 1947-05-10 Melt spinning process Expired - Lifetime US2571975A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US747252A US2571975A (en) 1947-05-10 1947-05-10 Melt spinning process
GB9948/48A GB653757A (en) 1947-05-10 1948-04-09 Melt-spinning process and apparatus therefor
FR974855D FR974855A (fr) 1947-05-10 1948-11-12 Procédé pour la filature de superpolyamides à l'état fondu
CH273680D CH273680A (fr) 1947-05-10 1948-11-27 Procédé pour la filature de filaments à partir de superpolyamides linéaires synthétiques, à l'état fondu.
BE486151A BE486151A (fr) 1947-05-10 1948-12-04 Procédé pour la filature de superpolyamides à l'état fondu
DEP28744D DE826615C (de) 1947-05-10 1948-12-31 Verfahren zur Herstellung von Faeden oder Fasern aus synthetischen, linearen Polyamiden

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US747252A US2571975A (en) 1947-05-10 1947-05-10 Melt spinning process

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US2571975A true US2571975A (en) 1951-10-16

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US747252A Expired - Lifetime US2571975A (en) 1947-05-10 1947-05-10 Melt spinning process

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US (1) US2571975A (fr)
BE (1) BE486151A (fr)
CH (1) CH273680A (fr)
DE (1) DE826615C (fr)
FR (1) FR974855A (fr)
GB (1) GB653757A (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2673163A (en) * 1949-09-14 1954-03-23 Bayer Ag Process for working up cellulose derivatives
US2898628A (en) * 1953-07-03 1959-08-11 Ici Ltd Melt-spinning apparatus
US2904109A (en) * 1953-03-30 1959-09-15 Ind Rayon Corp Method for the removal of monomers, etc., from molten polymers
US2943350A (en) * 1957-03-08 1960-07-05 Bayer Ag Polyamide melt spinning process and apparatus
US3005233A (en) * 1957-05-07 1961-10-24 British Celanese Melt spinning
US3010147A (en) * 1957-02-08 1961-11-28 British Nylon Spinners Ltd Apparatus and process for melt spinning
US3090773A (en) * 1958-01-28 1963-05-21 Allied Chem Caprolactam polymerization
US3093445A (en) * 1960-08-23 1963-06-11 British Nylon Spinners Ltd Manufacture of polyamide filaments
US3154613A (en) * 1962-03-29 1964-10-27 Celanese Corp Spinning filaments from solutions in concentrated sulfuric acid of a polyamide and salt
US3271817A (en) * 1963-05-27 1966-09-13 Maurice S Kanbar Nylon melt-spinning apparatus
US3624193A (en) * 1969-02-25 1971-11-30 Du Pont Polyamide filamentmaking process including solid-state polymerization
FR2313184A2 (fr) * 1975-06-04 1976-12-31 Nordson Corp Appareil de fusion et de distribution d'une matiere thermoplastique
US4952345A (en) * 1989-02-10 1990-08-28 E. I. Du Pont De Nemours And Company Method for controlling polymer viscosity

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1055174B (de) * 1957-03-08 1959-04-16 Bayer Ag Verfahren zur Herstellung von Faeden oder Fasern aus Polyamiden
DE1222200B (de) * 1957-03-28 1966-08-04 British Nylon Spinners Ltd Vorrichtung zum Schmelzspinnen von Polyamiden
NL287733A (fr) * 1962-01-15
CH688554A5 (de) * 1994-03-22 1997-11-14 Rhone Poulenc Filtec Ag Flusenarmes PA 6.6 Industriegarn.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2253176A (en) * 1938-08-09 1941-08-19 Du Pont Method and apparatus for production of structures
US2295942A (en) * 1940-08-02 1942-09-15 Du Pont Manufacture of filaments
US2303340A (en) * 1939-05-16 1942-12-01 Celanese Corp Production of artificial materials

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2253176A (en) * 1938-08-09 1941-08-19 Du Pont Method and apparatus for production of structures
US2303340A (en) * 1939-05-16 1942-12-01 Celanese Corp Production of artificial materials
US2295942A (en) * 1940-08-02 1942-09-15 Du Pont Manufacture of filaments

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2673163A (en) * 1949-09-14 1954-03-23 Bayer Ag Process for working up cellulose derivatives
US2904109A (en) * 1953-03-30 1959-09-15 Ind Rayon Corp Method for the removal of monomers, etc., from molten polymers
US2898628A (en) * 1953-07-03 1959-08-11 Ici Ltd Melt-spinning apparatus
US3010147A (en) * 1957-02-08 1961-11-28 British Nylon Spinners Ltd Apparatus and process for melt spinning
US2943350A (en) * 1957-03-08 1960-07-05 Bayer Ag Polyamide melt spinning process and apparatus
US3005233A (en) * 1957-05-07 1961-10-24 British Celanese Melt spinning
US3090773A (en) * 1958-01-28 1963-05-21 Allied Chem Caprolactam polymerization
US3093445A (en) * 1960-08-23 1963-06-11 British Nylon Spinners Ltd Manufacture of polyamide filaments
US3154613A (en) * 1962-03-29 1964-10-27 Celanese Corp Spinning filaments from solutions in concentrated sulfuric acid of a polyamide and salt
US3271817A (en) * 1963-05-27 1966-09-13 Maurice S Kanbar Nylon melt-spinning apparatus
US3624193A (en) * 1969-02-25 1971-11-30 Du Pont Polyamide filamentmaking process including solid-state polymerization
FR2313184A2 (fr) * 1975-06-04 1976-12-31 Nordson Corp Appareil de fusion et de distribution d'une matiere thermoplastique
US4952345A (en) * 1989-02-10 1990-08-28 E. I. Du Pont De Nemours And Company Method for controlling polymer viscosity
EP0382569A3 (fr) * 1989-02-10 1991-11-06 E.I. Du Pont De Nemours And Company Méthode de contrôle de la viscosité d'un polymère

Also Published As

Publication number Publication date
DE826615C (de) 1952-01-03
BE486151A (fr) 1951-06-15
CH273680A (fr) 1951-02-28
GB653757A (en) 1951-05-23
FR974855A (fr) 1951-02-27

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