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
  • 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
• • 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
  • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
  • D01F6/80—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from copolyamides

Definitions

• the present invention relates to a process for spinning an aqueous nitric acid solution of poly(hexamethylen'e') terephthalamide containing less 'than 0.05% of nitrous acid into an aqueous coagulation bath containing nitric acid.
• the present invention relates to a process of spinning fibers which comprises extruding a spinning solution into a coagulation bath of a 60% or less aqueous solution of nitric acid, said spinning solution being prepared by dissolving a polymer having 80% or more recurring units of poly(hexa.methylene)terephthalamide (said polymer is hereinafter abbreviated to poly(hexamethylenelterephthalamide) in a 65% or more aqueous solutionof nitric acid at a temperature less than 30 C., saidlatter nitric acid being as pure as not more than 0.05% of nitrous acid. (Percent hereinafter refers to that by weight unless specified otherwise.) V
• molded products of polyamide have been usually produced by a melt-molding process. It is an advantageous point for this melt-molding process that a solvent is not necessary and the molded product has a high filling grade.
• molding of the material is limited by its melting point. In-other words, the molding becomes difiicult in conformity to the higher melting point and it becomes impossible in case of a material having a very high melting point or a material having a melting point higher than a decomposition point.
• melt-molding can be easily exercised for a material having a low melting point.
• a melt-molding process is not suitable to produce a molded product having high degree of heat resistance.
• a process of producing molded products from poly(hexameth'ylene)terephthalamide is not yet known in view of industrial and economical advantages.
• trichloroacetic acid, trifluoroacetic acid, antimony trichloride, boron trifluoride and concentrated phosphoric acid or the like are cited as having the solvent ability for poly(hexamethylene)terephthalamide.
• nitric acid has been regarded as a strong oxidant substance and a process for producing the spinning solution by using nitric acid for a solvent of the said poly(hex-amethylene)terephthalamide has not yet been suggested.
• a spinning solution stabilized sufiiciently for producing the molded products can be obtained if poly(hexamethylene)terephthalarnide is dissolved in an aqueous solution of 65% or more of purified nitric acid, whence nitrous acid is removed, and the resultant solution is retained below the specified temperature.
• the required concentration of nitric acid which is variable by the average molecular weight of the aforesaid polymer and the compositions of the copolymer and is at least, 65 or more, preferably 70% or more.
• the spinning solution which is not separated in two layers for storage in the long period can be obtained.
• Nitrous acid in the aqueous solution of nitric acid is liable to color the spinning solution in yellowish orange and, in this case, the polymer regenerated from said spinning solution is also liable to be colored slightly yellowish.
• nitrous acid acts to depress the molecular weight of polymer in the spinning solution, so that the aqueous solution of nitric acid used in the present invention shall be beforehand purified so 'as to suppress the concentration of nitrous acid below 0.05%, preferably 0.02%.
• its temperature is also important.
• a temperature of storing the spinning solution shall be below 30 0., preferably 15 C.
• Various kinds of nitrates such as ammonium nitrate, sodi um nitrate, calcium nitrate, magnesium nitrate or the like may be appropriately added in the spinning solution of the present invention.
• Other components contain dibasic acids such as isophthalic acid, adipic acid, and sebacic acid diamine, pentamethylenediamine, oetamethylenediamine,'
• lactams such as caprolactam
• aminocarboxylic acids such as 6-aminocaproic acid, 9- aminononylic acid, and ll-aminoundecanoic acid
• mono carboxylic acids such as benzoic acid and acetic acid
• monoamines such as benzylamine, monomethylamine, etc.
• Suitable for the coagulation'bath used for producing the molded products such as fibers, film, etc. from said spinning solution is an aqueous solutionof nitric acid having concentration less than that of an aqueous solution of nitric acid used for producing the spinning solution and enabling to coagulate the spinning solution.
• the concentration of the aqueous solution of nitric acid is found to be 60% or less and preferably 50% or less.
• Poly(hexamethylene)terephthalamide is not coagulated in the aqueous solution of 60% or more of nitric acid and the coagulation is generally insufficient in the concentration of 50% to 60%.
• nitrates such as ammonium nitrate, sodium nitrate, calcium nitrate, magnesium nitrate, aluminium nitrate, zinc nitrate, etc. can be added in the coagulation bath to change the coagulation process.
• the molded products, coagulated in conformity to the present invention are stretched after being washed by water until nitric acid disappears substantially, but, if nec? essary, those may be stretched before or during the water detergence.
• the stretching after the water detergence is exercised by a hot water bath or a steam bath. If necessary, those products are stretched at a high temperature with heated plate or liquid bath of high boiling point.
• Films, fibers and other molded products obtained by the process of the present invention are very useful on the practical use.
• fibers having various deniers according to uses and having strengths suitable for practical uses can easily be obtained.
• the reduced specific viscosity of polyamide in the examples is measured at 35 C., when the polyamide is dissolved in the concentrated sulphuric acid in the 0.5
• the viscosities are indicated as follows:
• Poly (hexamethylene)terephthalamide having 1.24 dlj'g. of reduced specific-viscosity was added respectively into 78. 8% of nitric acid solution containing 0.0003% of nitrous acid, 78.8% of nitric acid solution containing 0.02% of nitrous acid and 78.8% of nitric acid solution containing 0.18% of nitrous acid, so as each resultant solution may keep 25 g./ 100 ml. of concentration; the first nitric'acid solution being purified by aeration and addition of 'urea. Those resultant solutions were stirred up and dissolved during one night at 0 C. One part of each resultant solution was taken up and regenerated by aqueous coagulation solution and dried sufficiently after water detergence.
• VllI wascolored'slightlyyellowish green.
• Example 111 Sixty grams of poly(hexamethylene)terephthalamide having 1.22 dl./ g. of. reduced specific viscosity was added in 200 ml. of,75% of nitric acid, purified so as to contain nitrous acid below "0.01% and the resultant mixture, stirred up and dissolved for 10 hrs., at C. and the spinning solution, colorless, transparent and stabilized was obtained.
• Said spinning solution was extruded through fine holes into the aqueous solution of ,42% of nitric acid maintained at 15 C. and coagulated and wound up on the roller. Then, the fibers were washed through the water bath until the acid of the fibers disappears substantially, and filaments in favorable whiteness were obtained through drying process and heat stretching process.
• the obtained fiber had a denier per filament of 3.0, the dry tensile strength was measured as 2.7 g./den. and the dry elongation as 26%.
• Example IV Sixty grams of poly(hexamethylene)terephthalamide having 1.35 dl./ g. of reduced specific viscosity was added in 200 ml. of 75% of nitric acid purified so as to contain nitrous acid below 0.01% and the resultant mixture was dissolved at 0 C. during 10 hrs., by being stirred up, and the spinning solution, colorless, transparent and stabilized was obtained. Said spinning solution was extruded through fine holes into the aqueous solution of 44% of nitric acid kept at 0 C. and was coagulated, and was wound up on the roller. Then, it was washed through water bath until the acid disappeared substantially, and filaments in favorable whiteness were obtained through drying and heat stretching processes. The obtained fiber had a denier per filament of 2.9 and dry tensile strength and dry elongation were measured as 3.1 g./den. and 25% respectively.
• Example V Seventy-five grams of poly(hexamethylene)terephthalamide having 1.78 dl./ g. of reduced specific viscosity was added in 300 ml. of 80% of nitric acid, purified so as to contain nitrous acid below 0.01% and the resultant mixture was dissolved at 0 C. during 10 hrs., while being stirred up, and the spinning solution, colorless, transparent and stabilized was obtained. Said spinning solution was extruded through fine holes into the aqueous solution of 40% of nitric acid kept at 30 C. and was coagulated therein and wound up on the roller. It was washed through water bath until the acid disappeared substantially, and filaments in the favorable whiteness were obtained through drying and heat stretching processes. The obtained fiber had a denier per filament of 3.0 and the dry tensile strength and the dry elongation were measured as 4.2 g./ den. and 22% respectively.
• Example VI Sixty grams of poly(hexamethylene)terephthalamide having 1.56 dl./ g. of reduced specific viscosity was added in 200 ml. of 75% of nitric acid, purified so as to contain nitrous acid below 0.01% and the resultant mixture, while being agitated, was dissolved at 0 C. for 10 hrs., and the spinning solution colorless, transparent and stabilized was obtained. The spinning solution was extruded through fine holes into the aqueous solution of 47% of nitric acid, kept at C., coagulated, and wound up on the roller. Then, those fibers were washed through the water bath until the acid disappeared substantially and filaments in the favorable whiteness were obtained through drying and heat stretching processes. The obtained fiber had a denier per filament of 3.1, dry tensile strength and dry elongation were measured as 39 g./ den. and 25% respectively.
• Example VII Seventy-five grams of poly(-hexamethylene)terephthalamide having 1.92 dl./ g. of reduced specific viscosity was added in 300 mLof of nitric acid, purified so as to contain nitrous acid below 0.01% and the resultant mixture, While being agitated, was dissolved at 5 C. for 15 hrs., and the spinning solution, colorless, transparent and stabilized was obtained. The spinning solution was extruded through the fine" holes into the aqueous solution of 42% ofnitric acid kept at 15 C., coagulated and wound up on the roller.
• the obtained fiber had a denier per filament of 1.45, dry tensile strength and dry elongation were measured as 4.6 g./den., and 11% respectively.
• Example VIII Seventy-five grams of poly(hexamethylene)terephthalamide having 2. 1 dl./ g. of reduced specific viscosity was added in 300 m1. of 80% of nitric acid, purified so as to contain nitrous acid below 0.01% and the resultant mixture, While being agitated, was dissolved at 15 C. for 5 hrs. The spinning solution, colorless, transparent and stabilized was obtained. The spinning solution was extruded through fine holes into the aqueous solution of 42% of nitric acid kept at 15 C., coagulated and wound up on the roller. Then, the fibers were washed through the water bath until the acid disappeared substantially. Filaments in favorable whiteness were obtained through drying and heat stretching processes. The obtained fiber had a denier per filament of 1.5, dry tensile strength and dry elongation were measured as 5.5 g./den. and 8% respectively.
• Example IX Sixty grams of copolymer, consisting of component of poly(hexamethylene)terephthalamide and 10% component of poly(hexamethylene)adipamide and having 1.30 dl./ g. of reduced specific viscosity was added in 200 ml. of 70% of nitric acid purified as to contain nitrous acid below 0.01%, and the resultant mixture was dissolved at 0 C. for 10 hrs. while being agitated, and the spinning solution, colorless, transparent and stabilized was obtained. The spinning solution was extruded through fine holes into the aqueous solution of 35% of nitric acid kept at 15 C., coagulated and wound up on the roller.
• the obtained fiber had a denier per filament of 3.0 and dry tensile strength and dry elongation were measured as 3.2 g./den. and 23% respectively.
• Example X Sixty grams of copolymer consisting of 90% component of poly(hexamethylene)terephthalamide and 10% component of poly(m-xylene)terephthalamide and having 1.36 dl./ g. of reduced specific viscosity was added in 200 ml. of 70% of nitric acid, purified as to contain nitrous acid below 0.01%. The resultant mixture was dissolved at 0 C. for 10 hrs., as it was being stirred up, and the spinning solution, colorless, transparent and stabilized was obtained. The spinning solution was extruded through fine holes into the aqueous solution of 35% nitric acid kept at 15 C., was coagulated and wound up on roller.
• the obtained fiber had a denier per filament of 3.1 and the dry tensile strength and the dry elongation were measured as 2.9 g./ den. and 24% respectively.
• a process of spinning fibers which comprises extruding a spinning solution into a coagulating bath of an aqueous solution of nitric acid in the coagulable concentration, the said spinning solution being prepared by dissolving a polymer having 80% or more recurring units of poly (hexamethylene)terephthalarnide at a temperature of 30 C. or -less into an, aqueous solution of nitric acid, purified so as to eontain the 0.05% of less concentration Qf nitrous acid.
• a process of spinning fibers which comprises extruding a spinning solution intov a c'oziglllating bath of an aqueous solution of 60%j c'oncentrationor less ofinitric acid, the said spinningsolution being prepared by dissolving and storing a polymerihaving 80 olimo're re eufl in g units of'poly(hexamethylene)terephthalamide at a temperatureof 30 C of less inan aqueouss olution of 65% JULIUS'jFROME', Primary Examiner. J. H; WOO, Ass'z'st' 'a'r li Exqniine7".

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

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Citations (2)

• 1966
  • 1966-07-21 US US566734A patent/US3399261A/en not_active Expired - Lifetime
  • 1966-08-12 BE BE685487D patent/BE685487A/xx unknown

Patent Citations (2)

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