US3093445A - Manufacture of polyamide filaments - Google Patents

Manufacture of polyamide filaments Download PDF

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Publication number
US3093445A
US3093445A US124394A US12439461A US3093445A US 3093445 A US3093445 A US 3093445A US 124394 A US124394 A US 124394A US 12439461 A US12439461 A US 12439461A US 3093445 A US3093445 A US 3093445A
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US
United States
Prior art keywords
chips
polycaprolactam
water
polyamide
filaments
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
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US124394A
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English (en)
Inventor
Freeman Ronald Frank James
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.)
British Nylon Spinners Ltd
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British Nylon Spinners Ltd
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Filing date
Publication date
Application filed by British Nylon Spinners Ltd filed Critical British Nylon Spinners Ltd
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Publication of US3093445A publication Critical patent/US3093445A/en
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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
    • 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
    • C08G69/46—Post-polymerisation treatment
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/56—Processes of molding lactams

Definitions

  • This invention relates to improvements in ior relating to the manufacture of polyamide filaments and more particularly to the melt-spinning of high molecular weight polycaprolactam -into filaments.
  • the invention is illustrated by the flow diagram in the drawing.
  • polycaprolactam By the term high molecular weight polycaprolactam is meant, more accurately, poly-epsilon-caprolactam of suiciently high molecular weight to be melt-spinnable into filaments.
  • This polyamide the preparation of which by the polymerization of the lactam is described in United States Patent No. 2,241,321 (Schlack), was manufactured already ⁇ during the second World War in Germany (under the trademark Perlon) and is now made also in Italy, U.S.A. and many other countries.
  • the properties of polycaprolactam are generally similar to those of polyhexamethylene adipamide (described in United States specication No.
  • This operation is advisedly eected before melt-spinning the polymer into filaments because not only is the presence of the low molecular weight material during melt-spinning undesirable but 4also its removal from the laments is inconvenient.
  • about two percent of low molecular ⁇ weight material are normally formed when pure polycaprolactam is melt-spun, or even more if the time during which the polymer remains molten is prolonged.
  • the polymer must therefore be purified so that it is practically free of said material before the melt-spinning. This purification may be carried out by various means, especially vaporisation in vacuum or extraction or both but for complete removal of the low molecular weight material extraction is often recommended, with or without a preceding vacuum treatment.
  • the present invention is based on the startling discovery that, provided certain conditions are observed during melt-spinning, the drying of the wet chip can be dispensed with. It is necessary to restrict the time during which the polycaprolactam remains molten in a manner .depending on the temperature. The maximum permissible time during which the polymer may lremain molten has also been found to depend on the pressure of the inert gas, under which lthe polycaprolactarn is melted, and on the total number of free carboxyl and amine end groups in the polycaprolactam. Under these conditions, which will be defined below, the proportion of low molecular weight material in the lresulting melt-spun filaments is found to Ibe acceptable for textile purposes. Since drying is an expensive process, the omission ⁇ of the drying stage constitutes an important economic advantage.
  • t maximum permissible time in minutes during which the polycaprolactam is maintained in a molten condition.
  • T temperature in degrees centigrade (ranging from 250 to 295 C.)
  • P pressure in atmospheres of inert gas (ranging from 0.5 to 5 atmospheres.)
  • E sum of the free amine and carboxyl end groups in the molten polycaprolactam expressed in gram equivalents per million grams.
  • NB-The free amine and carboxyl ends contained by the polycaprolactam are determined ⁇ by appropriate titration methods. The determination may be carried out on a sample of polymer taken from the melt pool or on a sample of the extruded filaments. It may be pointed out, however, that the values for the yamine and carboxyl ends found in the polycaprolactam chips are usually suitable for insertion in the above expression because, except in the case of polymers for which the sum of the amine and carboxyl ends is less than 80, the change in the values occasioned by melting can be neglected.
  • the present invention relates to a process for the manufacture of polyamide filaments by melting high molecular weight polycaprolactam chips at a temperature from 250 to 295 C. under an inert gas at a pressure from 0.5 to 5 atmospheres and extruding the molten polyamide in the form of filaments, characterised in that the polycaprolactam chips have been washed with water but not dried or only incompletely dried and contain over A by weight of water and that the polyamide is maintained in a molten condition for a period not exceeding in minutes the value of the expression:
  • the washing of the polycaprolactam chips with Water is intended to include the use of aqueous solutions for this purpose; thus, for example, an aqueous solution of caprolactam is often employed in the earlier stages of the washing which is completed with the aid of pure water.
  • the time during which the polyamide is maintained in a molten condition is advantageously not more than 80% of the period specified in the above paragraph, because, as already explained, the shorter the period in question, the smaller the proportion of low molecular material in the resulting filaments and it is preferred that the proportion of this low molecular material be below 2.0% by weight.
  • inert gases which prevent oxidation of the polyamide are: nitrogen, steam, helium and hydrogen.
  • the inert gas is preferably at or near atmospheric pressure, but it may be above or below atmospheric pressure. It is preferred that the inert gas be steam at a pressure which is atmospheric or within 3% of the existing atmospheric pressure. Even when the atmosphere of inert gas provided is other than steam, e.g. nitrogen, steam will in fact be present owing to its evolution when the undried or incompletely dried polycaprolactam is melted.
  • the process of the present invention may very desirably comprise melting high molecular Weight polycaprolactam chips containing over P11/2% water under steam at atmospheric pressure or within 3% thereof at between 265 C. and 280 C.
  • the polycaprolactam chips employed in carrying out the process of the present invention may contain much more water than 1A and it is frequently convenient to use without further drying polycaprolactam chips having a water content upwards of 31/2% or 7% when such chips become available in the course of industrial manufacture. Particularly is it desirable to make use of polyamide chips containing over 31/2% Water but insuicient to cause them to cake together or form a paste.
  • the polycaprolactam chips employed in accordance with the invention may contain conventional adjuvants such as delustrants, dyes, pigments and stabilisers.
  • Example l Polycaprolactam containing 0.15% of acetic acid and 0.4% of titania and having a relative viscosity of 2.63 as determined by the method quoted below, is extruded through a die and quenched in water to form bristles of 3/4 mm. diameter. These bristles are cut by means of a rotary cutter into chips mm. long.
  • the low molecular weight material contained in the chips amounts, as estimated by aqueous extraction, to 9.1%
  • the relative viscosity of the polycaprolactam is determined by dividing the viscosity of a 1% solution of the polymer in 96% aqueous sulphuric acid at 25 C. by the viscosity of the said aqueous sulphuric acid at the same temperature.
  • the polycaprolactam chips are washed in their own weight of water at C. for l hour, and the said washing repeated a further five times with fresh water whereby the proportion of low molecular weight material is reduced to 0.2% (calculated on the dry polymer).
  • the resulting chips are at 90 C. After most of the adherent water has been allowed to drain away, the chips are found to contain 14% of water.
  • the polyamide is found to contain 40 gram equivalents of amine ends and 65 gram equivalents of carboxy ends per l0G grams.
  • the chips are cooled to 35 C. by a blast of cold air.
  • the chips then contain 9% of water and flow freely if poured. After ⁇ being pneumatically transported to a storage bunker the chips have a water content of 7%.
  • the polycaprolactam chips are melted under steam at atmospheric pressure at a temperature of 270 C. in an apparatus similar to that illustrated in British specification No. 653,757.
  • the molten polyamide is extruded in the form of filaments at such a speed that the period during which the polyamide remains molten is 30 minutes.
  • the resulting filaments are found to posses a relative viscosity of 2.64 and to contain 1.5% of material which is extractable by water. After being stretched by known methods these filaments prove to be eminently suitable for textile purposes.
  • Example 2 Example 1 is repeated except that the rate of extrusion is reduced so that the period during which the polyamide remains molten in 45 minutes.
  • the resulting filaments are found to contain 2.2% of water-extractable material. After being drawn in the solid state to 4.95 times their original length, the filaments possess a denier of 15, a tenacity of 6.6 gm. per denier and an extensibility at break of 25%.
  • Example 3 Polycaprolactim chips having a relative viscosity of 3.31 and containing 11.5% of low molecular weight material are washed in the same manner as described in Example 1. The washed chips contain 0.3% water extractable material (calculated ou the dry polymer).
  • the chips After draining the chips contain 14% water. The water content is reduced to 12% by centrifuging and, when the chips have been pneumatically transported to a storage bunker, is found further to have fallen to 10%.
  • the polycaprolactam chips are melted at 270 C. under an atmosphere of steam at a pressure of 2.25 atmospheres.
  • the molten polycaprolactam contains 40 Igram equivalents of amine ends and 40 gram equivalents of carboxyl ends per 106 grams.
  • the molten polyamide is spun into filaments through a spinneret with 140 holes, the period during which it remains molten being 23 minutes.
  • the relative viscosity of the lilaments is 3.29; they contain 1.9% of low molecular weight material.
  • the extruded filaments are drawn in the solid state over a hot plate at approximately 185 C. to 5.3 times their original length, the iinal denier being 840.
  • the resulting filaments have a tenacity of 8.5 grams per denier and an extensibility at break of 16%.
  • Example 4 Example 3 is repeated except that the polycaprolactam chips of water content are further dried until they only contain 0.3% Water. The filament obtained exhibit similar good properties.
  • Example 5 This example is carried out in the same way as Example 3 except that the steam atmosphere employed during the melt-spinning is replaced by an atmosphere of nitrogen at the same pressure, namely 2.25 atmospheres. In this manner polycaprolactam filaments of similar properties are obtained.
  • a process for the manufacture of polyamide filaments containing not more than 2% of low molecular weight material and suitable for textile purposes which comprises melting high molecular weight polycaprolactam chips which have 'been washed with Water and incompletely dried and contain over 1A% by weight of water by heating said chips at a temperature from 250 C. to 295 C. under an inert gas at a pressure from 0.5 to 5 atmospheres, maintaining the polyamide in a molten condition for a period not exceeding in minutes the value of the following expression:
  • polycaprolactam chips contain over 31/z% by weight of water but insuflicient to cause them to cake together.
  • a process for the manufacture of polyamide filaments which comprises melting high molecular weight polycaprolactam chips which have been washed with water and incompletely dried and contain over 31/2% by weight of water by heating said chips at a temperature from 265 C. to 280 C. under steam at a pressure of between 0.67 and 1.33 atmosphere, maintaining the polyamide in -a molten condition for a period not exceeding in minutes lthe value of the following expression:
  • e is the base of the natural logarithms
  • T is the temperature in degrees centigrade
  • P is the pressure in atmospheres of the inert gas
  • E is the ysum of the free amine and carboxyl end groups in the molten polycaprolactam expressed in gram equivalents per million grams, and extruding the molten polyamide in the form of filaments.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Textile Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Polyamides (AREA)
  • Artificial Filaments (AREA)
US124394A 1960-08-23 1961-07-17 Manufacture of polyamide filaments Expired - Lifetime US3093445A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB29081/60A GB918930A (en) 1960-08-23 1960-08-23 Improvements in or relating to the manufacture of polyamide filaments

Publications (1)

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US3093445A true US3093445A (en) 1963-06-11

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US (1) US3093445A (is")
CH (1) CH415943A (is")
DE (1) DE1469032A1 (is")
ES (1) ES269475A1 (is")
GB (1) GB918930A (is")
NL (1) NL268474A (is")

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3271817A (en) * 1963-05-27 1966-09-13 Maurice S Kanbar Nylon melt-spinning apparatus
US3324061A (en) * 1962-01-15 1967-06-06 Minnesota Mining & Mfg Preparing aqueous solutions of polypyrrolidone
EP0201189A2 (en) 1985-04-22 1986-11-12 BASF Corporation Improved high speed process of making polyamide filaments

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5390420A (en) * 1977-01-13 1978-08-09 Teijin Ltd Polyamide yarn
US4632159A (en) * 1984-03-07 1986-12-30 Glasgo Marion L Clamp-on marking template and saw guide for making dovetail joints
DE3710803A1 (de) * 1987-03-31 1988-10-20 Basf Ag Verfahren zur entfernung von caprolactam und dessen oligomeren aus solches enthaltendem polyamidgranulat

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2571975A (en) * 1947-05-10 1951-10-16 Du Pont Melt spinning process

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2571975A (en) * 1947-05-10 1951-10-16 Du Pont Melt spinning process

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3324061A (en) * 1962-01-15 1967-06-06 Minnesota Mining & Mfg Preparing aqueous solutions of polypyrrolidone
US3271817A (en) * 1963-05-27 1966-09-13 Maurice S Kanbar Nylon melt-spinning apparatus
EP0201189A2 (en) 1985-04-22 1986-11-12 BASF Corporation Improved high speed process of making polyamide filaments
US4863664A (en) * 1985-04-22 1989-09-05 Basf Corporation High speed process of making polyamide filaments
EP0201189B2 (en) † 1985-04-22 1995-02-15 BASF Corporation Improved high speed process of making polyamide filaments

Also Published As

Publication number Publication date
ES269475A1 (es) 1962-03-16
GB918930A (en) 1963-02-20
DE1469032A1 (de) 1969-01-23
NL268474A (is")
CH415943A (de) 1966-06-30

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