Classifications

• • 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
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • 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
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters

Definitions

• the specific viscosity is determined by dissolving the polyethylene terephthalate in a mixture composed of 60 parts of phenol and 40 parts of tetrachloroethane to give a 1% solution and measuring the viscosity in a capillary viscosimeter at 25 C. Since portions of low molecular weight are contained in almost any polymer, it could not be foreseen in which way the addition of the aforementioned products would affect the properties of the polyethylene terephthalate and the filaments made thereof.
• the amount of the decomposing agent added must be limited and exactly dosed since by the addition of too great amounts of decomposing agents to the polyethylene terephthalate prior to the spinning process the various physical data of the filaments are adversely affected; thus, for example, the tensile strength of the filaments is strongly reduced if too great a quantity of decomposing agent is applied whereby the filaments obtained become brittle.
• the decomposing agent can be incorporated according to various methods:
• the desired amount of decomposing agent is added to the molten polyethylene terephthalate.
• the melt of polyethylene terephthalate is advantageously kept under an atmosphere of nitrogen of atmospheric pressure and the decomposing agent is slowly added, with agitation. After the addition of the decomposing agent, stirring is continued for 5 to 15 minutes.
• the polyethylene terephthalate obtained can either be fed in the molten state directly to the spinning head, for example with the aid of a screw conveyer, and there be spun into filaments, or the melt is forced through a slot die and cooled in the air or in water.
• the ribbon obtained is then worked up into granules in a cutting machine. These granules can be stored and transported. From these polyethylene terephthalate granules there are obtained filaments when, after drying the granules to a water content of less than 0.04%, they are melted again and the melt is forced through a spinneret by means of spinning pumps and the filaments obtained are taken off.
• the melt of polyethylene terephthalate obtained after the polycondensation is formed into ribbons and these are worked up into granule-s in a cutting machine. These granules are mixed with the desired amount of the decomposing agent which should preferably be in the pulverulent or granular state. In order to warrant that the granules are intimately mixed with the decomposing agent, it is necessary to mix the composition for several hours, for example in an offset tumbling mixer. It is advantageous to add the decomposing agent to the granules prior to drying the granules and then to dry the mixture to a water content of less than 0.04% of its weight.
• the pulverulent or granular decomposing agent is bonded to the granules so that in the further processing of the mixture a uniform distribution of the decomposing agent in the granules is warranted.
• the mixture is melted, in the course of which procedure the decomposing agent is dissolved in the melt of the polytageous to use as highly a concentrated solution as possible.
• This solution is added to the polyethylene terephthalate obtained after the polycondensation which, after extrusion into ribbons and comminution, is available in grandular form, while the desired amount of the decomposing agent has to be metered in carefully.
• the solution of the decomposing agent must be well mixed with the granular product.
• the solvent is gradually evaporated. This can either be done by creating a vacuum or by slowly heating the composition to a temperature situated a few degrees above the boiling point of the solvent.
• the decomposing agent deposits in a finely distributed formon the surface of the granular product.
• the granules thus obtained are dried to a water content'of' less than 0.04% by weight. Owing to the uniform deposition of the decomposing agent on the granular product, the uniform distribution is warranted even 'in the case of a further processing.
• the granules are melted while the decomposing agent is dissolved in the melt of the polyethylene terephthalate and the polyethylene terephthalate decomposes to the desired extent.
• the melt obtained has a lower viscosity than the melt of the original polyethylene terephthalate. With the aid of spinning pumps the melt is forced through a spinneret and shaped into filaments that can be subjected to a further treatment in known manner.
• Example 1 1 kg. of polyethylene terephthalate granules (specific viscosity: 0.85) were prepared from terephthalic acid and ethylene glycol in known manner and mixed with grams of a granular transesterification product of dimethyl terphthalate and glycol (melting point: 150 to 160 C.), then dried for two hours at 180 C. and spun at 290 C. in a melt spinning installation through a spinneret having 200 holes. After spinning the polyethylene terephthalate had a specific viscosity of 0.55. The melting point of the polyethylene terephthalate was not noticeably reduced by the spinning process (melting point: 250 C.).
• the filaments were heated and stretched in the ratio of 1:3.65, crimped, prepared, subjected to heat setting and cut.
• the normal polyethylene terephthalate fibers had a tensilev strength of 3.8 grams per denier and an elongation at break of while the fibers prepared according to the process of the present invention had a tensile strength of 3.4 grams per denier and an elongation at break of 23%.
• the yarns (No. 48 double/500 twists S/500 twists Z) which were spun from the staple fibers prepared according to this example had a considerably lower pilling efiect than normal polyethylene terephthalate yarns.
• Example 2 1 kg. of granulated polyethylene terephthalate was prepared as described in Example 1 and mixed with 10 g. of dimethyl terephthalate. After drying, the mixture was spun into filaments in a melt spinning installation. The filaments. had a specific'vi cosity of 0.57 and a meltin point of about 258 C. They were stretched as described in Example 1 and processed into staple fibers. The tensile strength of normal polyethylene terephthalate fibers is 3.8 grams per denier with an elongation at break of 25 Fibers prepared according to this example had a tensile strength of 3.3 grams per denier and an elongation at break of 22%. The yarns (No. 40 double/400 twists 8/450 twists Z), which were spun from the staple fibers prepared according to this example, had an appreciably lower tendency towards pilling.
• Example 3 10 grams of dimethyl terephthalate were dissolved in cc. of acetic acid ethyl ester and 1 kg. of granulated polyethylene terephthalate was added to this solution. Then the acetic ester was evaporated in vacuo, the lacquered granules were dried and processed according to the melt extrusion process intofibers as described in Example 2. The yarns obtained possessed the same properties as those obtained according to Example 2.
• Example 4 30 grams of diglycol terephthalate were dissolved in Example 5 200 kg. of polyethylene terephthalate were prepared in a vessel (capacity: 500 kg.) by transesterification from dimethyl terephthalate and ethylene glycol and subsequent condensation, as usual. As soon as the condensation mass had attained a specific viscosity of 0.85, 1 kg. of diglycol terephthalate (preliminary condensate) was charged to the condensation vessel in small portions without vacuum, under an atmosphere of nitrogen, while agitation was continued for 15 minutes at 280 C. Then the molten contents of the vessel were discharbed and the melt granulated in the usual manner. The granules had a specific viscosity of 0.6.
• the polyethylene terephthalate filaments prepared therefrom in a melt spinning installation were processed into staple fibers as described in Example 1.
• the filaments had a tensile strength of 3.5 grams per denier. From the staple fibers there was obtained a yarn (No. 48 double/500 twists S/500 twists Z) which had a very low tendency towards pilling.
• a process for manufacturing polyethylene terephthalate fibrous structures having improved wearing prop erties which comprises admixing polyethylene terephthalate having a specific viscosity of about 0.8 to about 0.9 with 0.1 to 5% by weight, calculated on the weight of said polyethylene terephthalate, of a decomposing agent selected from the group consisting of dimethyl terephthalate, dimethyl isophthalate, diglycol terephthalate and diglycol isophthalate, reacting said mixture to decompose said polyethylene terephthalate to a specific viscosity of about 0.5 to about 0.6, and spinning said mixture to form said fibrous structures, said specific viscosity being determined by measuring the viscosity of a 1% solution of said polyethylene terephthalate in a mixture of 60 parts phenol and 40 parts tetrachloretha'ne in a capillary viscosimeter at 25 C.
• a process as defined in claim 1 wherein said polyethylene terephthalate is in granular form and said step of admixing said polyethylene terephthalate and said decomposing agent, prior to reacting them, comprises dissolving said decomposing agent in a solvent selected from the group consisting of methylene chloride, dioxane, acetic acid ethyl ester and ethanol, applying the solution of said decomposing agent and said solvent to said polyethylene terephthalate granules, evaporating said solvent from said granules, and drying said granules.
• the step of improving the wearing properties of said fibrous structures which comprises admixing with polyethylene terephthalate having a specific viscosity of about 0.8 to about 0.9, 0.1 to 5% by weight, calculated on the weight of said polyethylene terephthalate, of a decomposing agent selected- References Cited by the Examiner UNITED STATES PATENTS 2,799,664 7/1957 2,897,042 7/ 1959* Heiks 8130.1 2,938,811 5/1960 Hermes 117102 3,014,011 12/1961 Zoetbrood 260 3,070,575 12/1962 Cramer 26047 FOREIGN PATENTS 728,550 4/1955 Great Britain.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (1)

Publications (1)

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Cited By (5)

Citations (6)

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• 0
  • NL NL269134D patent/NL269134A/xx unknown
  • NL NL121430D patent/NL121430C/xx active
• 1960
  • 1960-09-14 DE DEF32112A patent/DE1256837B/de active Pending
• 1961
  • 1961-09-12 US US137508A patent/US3245955A/en not_active Expired - Lifetime
  • 1961-09-14 GB GB33044/61A patent/GB986619A/en not_active Expired
  • 1961-09-14 BE BE608188A patent/BE608188A/fr unknown

Patent Citations (6)

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