US3839520A - Process for producing porous acrylic fibers - Google Patents

Process for producing porous acrylic fibers Download PDF

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Publication number
US3839520A
US3839520A US00330765A US33076573A US3839520A US 3839520 A US3839520 A US 3839520A US 00330765 A US00330765 A US 00330765A US 33076573 A US33076573 A US 33076573A US 3839520 A US3839520 A US 3839520A
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liquid
spinning solution
fiber
spinning
aqueous
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US00330765A
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T Kobashi
N Abe
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Wyeth Holdings LLC
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American Cyanamid Co
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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
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/24—Formation of filaments, threads, or the like with a hollow structure; Spinnerette packs therefor
    • D01D5/247—Discontinuous hollow structure or microporous structure
    • 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
    • D01D5/06—Wet spinning methods
    • 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
    • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/18—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide
    • 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
    • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/38—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated nitriles as the major constituent
    • 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
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/2935—Discontinuous or tubular or cellular core

Definitions

  • PROCESS FOR PRODUCING POROUS ACRYLIC FIBERS Filed Feb. 8. 1973 H c g I I /0 20 30 RATE OF /N TRODUC r/o/v 0F INERT 6A6 (//v 5) VOLUME BASED 0/ ⁇ / VOLUME 0F SPl/V/V/lVG SOLUT/ON/ RATE OF I/VTRODUCT/O/V 0F //V/?7' L/OU/D (/IV B) WE/GHT BASED ON WEIGHT 0F .SPl/V/V/NG SOLUTION) United States Patent 3,839,520 PROCESS FOR PRODUCING POROUS ACRYLIC FIBERS Toshiyuki Kobashi, Tsulrubo-gun, and Noboru Abe, Okayama, Japan, assignors to American Cyanamid Company, Stamford, Conn.
  • This invention relates to a process for preparing porous acrylic fibers from a spinning solution prepared by dissolving a fiber-forming acrylonitrile polymer in an aqueous inorganic solvent therefor.
  • the present invention relates to an industrially advantageous process for producing porous acrylic fibers containing numerous stable fine cavities therein and having excellent physical properties, which process comprises dispersing in a spinning solution of an acrylonitrile polymer in an aqueous inorganic solvent both an inert low-boiling liquid which is substantially in soluble therein and an inert gas, wet-spinning the thus modified spinning solution into an aqueous coagulant under conditions such that said low-boiling liquid is not evaporated or dissolved, and thereafter heating the thus coagulated filaments so as to evaporate the low-boiling li uid.
  • an inert gas is dispersed in the spinning solution and the resulting dispersion is spun into fibers.
  • the process requires use of a special dispersing device such as a colloid mill to disperse the gas as fine bubbles Within the spinning solution.
  • a special dispersing device such as a colloid mill to disperse the gas as fine bubbles Within the spinning solution.
  • it is extremely difficult to provide gas bubbles of the fine diameter necessary. Consequently, the process leads to frequent stoppages due to filament breakages in spinning and stretching steps and it has not been possible to maintain the necessary continuity of processing necessary for commercial production.
  • a low-boiling liquid is dispersed in the spinning solution, the modified spinning solution is then Wet-spun and coagulated, and the liquid is evaporated.
  • an insufiicient number of cavities are obtained in the filaments obtained to provide the desired degree of porosity.
  • Increasing usage of the low-boiling liquid to increase porosity not only increases production costs dramatically but also leads to unacceptable fiber properties, particularly strength and elongation.
  • a process for preparing porous acrylic fibers which comprises preparing a spinning solution of a fiber-forming acrylonitrile polymer containing at least about 70 weight percent acrylonitrile and the balance of one or more vinyl monomers copolymerizable therewith in an aqueous inorganic solvent therefor, dispersing therein as bubbles of an average diameter less than about 50 3,839,520 Patented Oct. 1, 1974 "Ice microns both an inert liquid having a boiling point in the range of 30l00 C.
  • the low-boiling liquid useful in the process of the present invention is an inorganic or organic compound which is substantially insoluble in the spinning composition and in the aqueous coagulant used therewith. It must have a boiling point in the range of 30 to 100 C., and preferably in the range of 60 to C.
  • Suitable lowboiling liquids are exemplified by carbon tetrachloride, butyl chloride, propionyl chloride, propyl chloride, allyl chloride, isoamyl chloride, trichloroethylene, trichloroethane, benzene, n-hexane, cyclohexane, cyclohexadiene, cyclopentane, dimethylbutane, dimethylfuran and carbon disulfide.
  • a preferred liquid is n-hexane.
  • the low-boiling liquid is soluble in the spinning composition, it will be impossible to obtain fiber having the porosity characteristics that are the object of the present invention. Furthermore, if the low-boiling liquid is soluble in the aqueous coagulant, it will also be impossible to obtain fiber having the porosity characteristics that are the object of the present invention.
  • the term substantially insoluble as used in the present specification and claim is intended to refer to a low-boiling liquid whose solubility does not exceed about 0.5 weight percent at 20 C. in either the spinning solution or the aqueous coagulant.
  • Low-boiling liquids having boiling points below about 30 C. cannot be employed in the process of the present invention because the spinning solutions involving aqueous inorganic polymer solvents are generally employed in wet-spinning at temperatures that would cause premature evaporation of the low-boiling liquid and consequent loss of the desired fiber porosity.
  • Liquids having boiling points above about C. cannot be effectively employed in the process of the present invention because they are too difiicult to expand quickly and to evaporate from the fiber under the conditions normally associated with wet processing of wet-spun acrylic fibers.
  • the inert gas useful in the process of the present invention is non-reactive with and substantially insoluble in the spinning solution and coagulant.
  • Suitable gases include, for example, air, nitrogen, argon, helium, and
  • the sole Figure of the present specification is an orthogonal coordinate diagram resulting from plotting the etfective usage levels of low-boiling liquid and inert gas and connecting the points so as to provide an enclosed effective area that represents the codependent relationship between usage of low-boiling liquid and usage of inert gas that is effective in the process of the present invention.
  • the etfective coordinates connected are represented as A (1, 5), B (1, 0.01), C (30, .01). D (30, 0.5) and E (5, 5).
  • the area represented by the smaller diagram results from connecting coordinates F (2, 2), G (2, 0.05), H (10, 0.05), I (10, 0.5) and J (5, 2) and indicates a preferred codependent relationship between usage of low-boiling liquid and usage of inert gas.
  • the values of low-boiling liquid plotted are weight percentages based on the weight of the spinning solution.
  • the values of inert gas are volume percentages based on the volume of spinning solution. Usages of low-boiling liquid and inert gas within the area defined by connecting the coordinates, as shown in the figure, lead to the desirable results of the present invention. Usages outside the area enclosed by connecting the coordinates result in loss of the desirable properties achieved by the present invention.
  • the inert gas and low-boiling liquid may be introduced into the spinning solution by any convenient method for dispersion therein.
  • the low-boiling liquid may be intro Jerusalem and dispersed in the spinning solution first, fol lowed by introduction and dispersion of the inert gas.
  • the inert gas may first be introduced and dispersed in the spinning solution followed by introduction and dispersion of the low-boiling liquid.
  • a particularly preferred method of introduction is to prepare first a gaseous mixture by dispersing the low-boiling liquid in the form of a gas or mist into the inert gas and then introducing and dispersing this gaseous mixture into the spinning solution. This preferred procedure of introduction and dispersion of low-boiling liquid and inert gas enables extremely fine bubble sizes to be obtained in the spinning solution.
  • a particularly effective mechanical device is a planetary gear type liquid disintegrator or an in-line homomixer used in conjunction with transport of the solution. It is generally preferred to carry out dispersing until the average bubble diameter in the spinning solution is not more than about 50 microns, preferably not more than about microns, as measured from photomicrograph determinations, as later described. When the average bubble diameter exceeds about microns, problems with respect to spinnability, filament breakage at the time of spinning and stretching, and non-uniform pores may result. Therefore, it is desirable to maintain bubble diameter below about 50 microns to avoid such potential problems.
  • the spinning solution with its dispersed content of low-boiling liquid and inert gas is then spun into an aqueous coagulating bath in accordance with conventional wet-spinning procedures.
  • the aqueous coagulating bath is maintained at a temperature below about 20 C. and preferablybelow about 10 C. and coagulation is effectively accomplished.
  • Use of aqueous coagulating bath temperatures in excess of about 20 C. results in devitrification of acrylic fibers obtained from aqueous inorganic solvent solutions of fiber-forming acrylonitrile polymers and is to be avoided.
  • the bubbles introduced into the spinning solution by the combination of lowboiling liquid and inert gas are present in the fiber coagulated as specified.
  • the coagulated fiber is water-washed, which may be accompanied by partial stretching, in accordance with conventional procedures. Such water-washing does not involve temperatures in excess of about 20 C.
  • the washed fiber is then treated in hot water or steam at temperatures at or above the boiling point of the lowboiling liquid while the fiber is still in a homogeneous swollen gel state. By such treatment, the low-boiling liquid present in the liquid state in the swollen gel fiber is quickly evaporated so as to leave fine cavities Within the fiber.
  • the cavities result from evaporation of the low-boiling liquid alone, such liquid in conjunction with inert gas, or from coalescence of cavities resulting from evaporation of lowboiling liquid and escape of inert gas entrapped in the initially coagulated fiber, i.e. prior to use of hot water or steam.
  • the cavity-containing fiber is then stretched in hot water at a temperature above about C. Such stretching causes elongation of the cavities in the direction of stretching and the fiber thus obtains uniform elongated cavities over its entire length.
  • Hot-stretching may be in a single step or in staged amounts in multiple steps. Some stretching may also accompany water-washing prior to cavity formation by taking advantage of the limited cold stretchability of the spun filament. Stretching may also be carried out by use of steam.
  • the stretching contemplated is that conventionally employed for fiber orientation purposes.
  • the swollen gel fiber containing cavities and oriented by hot-stretching is then compacted as to fiber structure by drying and may be subjected to such additional conventional processing steps as may be desired.
  • additional steps include, for example, heat-relaxation, finishing agent treatment, and post-drying, as are conventionally employed.
  • the acrylic fiber obtained by the process of the present invention has elongated fine cavities uniformly distributed over the entire fiber length. These cavities are not collapsed by any subsequent processing steps such as stretching, compacting, or crimping steps.
  • the resulting fiber also has high strength and elongation properties and is eminently suitable for such uses as clothing, bedding, and stuffing by virtue of its light weight and elastic and insulating properties, which are important requirements for many industrial uses.
  • the acrylonitrile polymer useful as the fiber-forming polymer may be a homopolymer of acrylonitrile or a co polymer containing at least about 70 weight percent acrylonitrile and the balance of one or more vinyl monomers copolymerizable therewith. A mixture of polymers may also be employed.
  • an aqueous inorganic solvent is required.
  • suitable inorganic solvents include concentrated aqueous solutions of thiocyanate salts, such as sodium, potassium, ammonium, and calcium thiocyanates, zinc chloride, and perchloric, nitric, and sulfuric acids.
  • Organic solvents such as dimethylformamide, dimethylacetamide, or dimethyl sulfoxide, cannot be used in the process of the present invention since they dissolve the low-boiling liquid and do not enable the required dispersed state thereof to be achieved.
  • the concentration of acrylonitrile polymer in the spinning solution is generally in the range of about 5 to 25 weight percent, based on the weight of the spinning solution, and is influenced by the molecular weight of the polymer, as'is known.
  • the aqueous coagulant employed is that normally associated with the particular aqueous inorganic polymer solvent employed. No special requirements as to aqueous ratio of 5 in boiling water.
  • the boiling water treatment also caused the low-boiling liquid to gasify and evaporate from the fiber with the entrapped air to provide cavities in the fiber.
  • the fiber was then dried in air at 120 C. to compact the structure and finally heat-relaxed in saturated 5 coagulant are imposed by the process of the present insteam at 125 C.
  • the various modifications and detalls vention. are given in Table I.
  • Each portion of the spinning solution processed in accordance with the present invention was modified with both low-boiling liquid and inert gas (air) as indicated in Table I.
  • the spinning solutions thus modified by incorporation of low boiling liquid and air were agitated by means of a planetary gear type liquid disintegrator so as to provide the average bubble diameter given in Table I.
  • the low-boiling liquid and air were introduced into the spinning solution separately, the liquid being added first.
  • the modified spinning solution in each instance, was spun into an aqueous coagulation bath at 0 C. consisting of a 12% aqueous solution of sodium thiocyanate.
  • the spinnerette contained orifices, each of 0.1 millimeter diameter.
  • the coagulated fiber was water-washed at 20 C. and stretched at a stretch ratio of 2 in conjunction therewith. The washed fiber was then stretched at a stretch We claim:
  • a process for preparing porous acrylic fibers which comprises preparing a spinning solution of a fiber-forming acrylonitrile polymer containing at least about 70 weight percent acrylonitrile and the balance of one or more vinyl monomers copolymerizable therewith in an aqueous inorganic solvent therefor, dispersing therein as bubbles of an average diameter less than about 50 microns both an inert liquid having a boiling point in the range of 30100 C.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Artificial Filaments (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
US00330765A 1972-04-10 1973-02-08 Process for producing porous acrylic fibers Expired - Lifetime US3839520A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2342358A1 (fr) * 1976-02-27 1977-09-23 Bayer Ag Fibres et filaments hydrophiles en polymeres synthetiques
FR2343833A1 (fr) * 1976-03-10 1977-10-07 Bayer Ag Procede de fabrication de fibres et de filaments hydrophiles a partir de polymeres synthetiques
EP0180097A2 (en) * 1984-10-19 1986-05-07 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Foamed synthetic fiber and its manufacturing method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6459782B2 (ja) * 2015-05-29 2019-01-30 東洋インキＳｃホールディングス株式会社 気泡含有液状物、およびその製造方法、並びにその利用

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2342358A1 (fr) * 1976-02-27 1977-09-23 Bayer Ag Fibres et filaments hydrophiles en polymeres synthetiques
FR2343833A1 (fr) * 1976-03-10 1977-10-07 Bayer Ag Procede de fabrication de fibres et de filaments hydrophiles a partir de polymeres synthetiques
EP0180097A2 (en) * 1984-10-19 1986-05-07 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Foamed synthetic fiber and its manufacturing method
EP0180097A3 (en) * 1984-10-19 1988-09-07 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Foamed synthetic fiber and its manufacturing method

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ES413531A1 (es) 1976-05-16
JPS51210B2 (es) 1976-01-06
JPS48103827A (es) 1973-12-26
CA1038579A (en) 1978-09-19

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