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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
  • D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
  • D01F9/15—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from coal pitch
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
  • D01F9/155—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from petroleum pitch
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
  • D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
  • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
  • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
  • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
  • D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
  • D01F9/24—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

• the invention resides in a resilient fiber or fiber assembly derived from a stabilized carbonaceous precursor material having imparted thereto a spring-like structural configuration capable of reversible deflection of greater than about 1.2 times the length of the fiber when in a relaxed condition.
• the carbonaceous fiber of the present invention is provided with a substantially permanent, non-linear, resilient, elongatable, spring-like structural configuration, e.g. of a substantial coil-like, sinusoidal or other multi-curvilinear configuration having no sharp or acute angular bends in the fiber.
• the spring-like structural configuration and the resilient, elongatable, characteristics of the fiber allows for a dimensional change of the fiber from a relaxed condition (ie. spring-like configuration) to an elongated, stretched, and substantially linear state, or any degree there-in-between, in which the fiber is under tension.
• the fiber When placed under tension, the fiber can be extended at least 1.2 times, typically from 2 to 4 times, the length of the fiber in its relaxed non-deflected spring-like configuration.
• the spring-like fiber can thus be deflected (elongated or stretched) to a substantially linear shape or configuration. If the modulus of elasticity of the fiber per se is not approached or exceeded, that is to say the fiber is not put under tension beyond that necessary to straighten the fiber to a substantially linear shape, the fiber is capable of returning from the linear to its relaxed spring-like shape over many cycles of stress elongation and relaxation without either breaking or substantially altering the dimensions or physical structure of the fiber.
• the prior art has generally taught the manufacture of filaments from pitch based (petroleum and/or coal tar) compositions by the conventional technique of melt spinning the composition into continuous filaments which can then be stabilized by oxidation. Such filaments are taught to be useful per se.
• the continuous filament may be chopped or stretch-broken into what the art refers to as a "staple" fiber. Such "staple" fiber can be converted into a yarn by drafting, drawing and/or twisting, (referred to as spinning in the industry).
• the continuous filaments can also be made into a tow formed from a plurality of continuous mono-filaments. The resulting yarn or threads are used per se or may be woven into cloth-like articles and used as such.
• a woven article may be carbonized to produce a graphite or graphite-like cloth.
• a tow per se may be carbonized, without weaving the tow into a cloth, and thereafter used as a reinforcement material for synthetic resinous materials e.g. "pre-preg", and the like.
• polyacrylonitrile can be wet spun into filaments; the filaments assembled into filament tow; the filaments or tow stabilized by oxidation; the filaments or tow made into staple by chopping or stretch breaking; the staple spun into yarn; the yarn knitted or woven into a cloth or fabric; and, if desired, the resulting fabric carbonized at a temperature of greater than 1400°C.
• PAN polyacrylonitrile
• These materials in their pre-carbonized woven state, have been used as a non-combustible reinforcing material for metallized fire fighting suits. In their unwoven carbonized form, these materials have also been used as a reinforcement material for synthetic resinous materials such as golf club shafts, and the like.
• a knitted fabric cannot be deknitted without special care and such a deknitted yarn cannot thereafter be carded to convert the fibers in the yarn into a wool-like fluffy material without causing severe destruction, i.e. breakage, of the fibers.
• the resulting short and broken fibers do not have sufficient length or crimp to produce a well entangled fluff.
• the prior art also generally discloses carbonized filaments having a high tensile strength or a high surface area.
• Such filaments are of a highly "graphitic" nature and necessitate the utilization of high temperatures to obtain a high degree of carbonization.
• the filaments produced by such a high temperature treatment are very brittle and incapable of standing up to stress such as repeated bending of the filaments, particularly when they have been subjected to a temperature above about 1000°C, and more so when they have been subjected to a temperature of above about 1400°C.
• Exemplary of a high temperature treatment of filaments derived from stabilized mesophase pitch can be found in U.S. Patent No.
• fiber or “filament” interchangeably refers to a fine threadlike body or structure of a natural or synthetic material in the conventional usage. Included herein are filaments made by melt spinning a pitch based composition such as petroleum or coal tar, or fibers which are made by wet spinning a synthetic resinous material such as polyacrylonitrile.
• Fiber assembly refers to a multiplicity of filaments commonly referred to in the textile industry as a tow or yarn. Fiber assemblies are made of common polymeric textile fibers or filaments, but are also applicable to carbonaceous fibers or filaments which have been stablized and treated in accordance with the following teaching and examples.
• spring-like “spring-like structure”, or “spring-like structural configuration” are interchangeably used herein to designate a fiber, yarn or tow that is physically deformed from a substantially linear configuration into a coil-like, sinusoidal, or other multi-curvilinear form or configuration having no acute angular bends.
• nK n is a numerical value in increments of 1000 filaments.
• staple refers to a non-continuous strand of threads or fibers which may be "spun” (drafted, drawn and/or twisted) into yarns or threads which are used in the textile industry in forming woven and/or knitted articles.
• stabilized herein applies to fibers or tows which have been oxidized at a specific temperature, typically less than about 250°C for PAN fibers, provided it is understood that in some instances the fibers are oxidized by chemical oxidants at lower temperatures.
• spun herein applies to a continuous strand of twisted filaments, threads or fibers.
• spun yarn refers to continuous strands of staple fibers which have been drafted, drawn and/or twisted into threads or yarns.
• carding herein refers to a pro- cedure in which a yarn is combed or brushed with a toothed apparatus, e.g. a wire tooth brush, to effect at least a partial alignment of the staple fibers into an entangled web or sliver.
• a toothed apparatus e.g. a wire tooth brush
• garnettted refers to a process for reducing various textile waste materials to fiber by passing them through a machine called a garnett, which is similar to a card.
• knitting herein includes single Jersey knit, Rib knit, Pearl knit, Interlock knit, Double knit, and similar methods of knitting a fiber, yarn or tow into a cloth.
• Carbonaceous precursor starting materials which have the capability of forming the spring-like structural configuration fiber of the invention are selected from starting materials such as pitch (petroleum or coal tar), polyacetylene, polyacrylonitrile (PANOX or GRAFIL), polyphenylene, SARAN (Trade Mark), and the like.
• the carbonaceous precursor material should have some degree of skeletal orientation, i.e. have substantial concentrations of oriented, fused, benzenoid structural moieties or moieties which are capable of conversion, on heating, to fused benzenoid or equivalent skeletal orientation at or near the surface.
• Preferred precursor materials are prepared by melt spinning or wet spinning in a manner to yield a monofilament or multi-filament assembly.
• the filaments are stabilized by oxidation or dehydrochlorination and then converted into a yarn, tow, or a woven cloth or knitted cloth by any of a number of commercially available techniques.
• an article derived from a stabilized, carbonaceous precursor material comprising a partially carbonized or substantially completely carbonized fiber and being characterised in that the fiber has a spring-like structural configuration with a reversible deflection ratio of greater than about 1.2:1.
• the fiber has a diameter of 4 to 20 micrometers.
• a method of forming a fiber with reversible deflection from a stabilized, carbonaceous precursor material comprising the steps of imparting a spring-like shape to the stabilized fiber, heating the fiber having said spring-like shape in a relaxed state under non-oxidizing conditions and at a temperature sufficient to impart a temporary setting of a spring-like structural configuration to the fiber, and/or heating the fiber having said spring-like shape in a relaxed state under non-oxidizing conditions to a temperature sufficient to impart a permanent setting of a spring-like structural configuration to the fiber.
• a unique article is prepared from such a carbonaceous precursor material which is made into a fiber, yarn or tow of fibers, stabilized and then provided with a spring-like structural configuration, imparting to the fiber flexible, resilient, elongatable and deflectable characteristics, without altering the spring-like configuration of the fiber over many cycles of elongation and contraction.
• Fibers made from PAN are generally oxidation stabilized at a temperature of from 200°C to 250°C and typically have a nominal diameter of from 10 to 20 micrometers.
• Fibers made from mesophase pitches are oxidation stabilized at a temperature of from 250° to 400 * C, preferably at a temperature of from 300° to 390°C, as described in U.S. Patent No.
• Fibers made from SARAN are stabilized by dehydrochlorination in which the SARAN fiber loses its thermoplastic nature and begins to take on a thermoset- like behavior. It will be understood that fibers having a somewhat larger diameter of, for example, 30 micrometers may be employed where stiffer fibers are desired, depending upon the particular end use to which such heavier and stiffer fibers are to be applied.
• a multiplicity of continuous fibers are associated into a tow which is then stabilized by oxidation in conventional manner.
• the stabilized tow (or staple yarn made from chopped or stretch-broken fiber staple) is thereafter, and in accordance with the present invention, formed into a coil-like structural configuration as, for example, by winding the tow on a cylindrical rod or mandrel, or is formed into a sinusoidal form or other multi-curvilinear form by knitting the tow or yarn into a fabric or cloth (recognizing that other fabric forming and coil forming methods can be employed). It is convenient to form the sinusoidal structure on a standard textile knitting machine (e.g.
• the coil-like or sinusoidally shaped fiber, tow or the knitted cloth is thereafter heat treated at a temperature of from 150°C to 1550°C. At a temperature of above about 250°C, the fiber, tow or cloth is heat treated in an inert atmosphere. If the desired end product requires subsequent mechanical treatment, ie. carding or deknitting of the fabric, it is preferable to subject the fiber, tow or cloth to a temperature below about 550°C in an inert atmosphere.
• the fibers are provided with a temporary set and have not yet acquired the high degree of brittleness associated with "graphite" fibers.
• the fibers are, ab initio, provided with a permanent set.
• Such permanent set is accompanied by some degree of orientation and brittleness which can lead to breakage of some fibers during subsequent treatment of the fibers, particularily if the treatment is carried out with short staple fibers which are highly entangled.
• the fiber not be heated to a temperature above about 275°C, while under tension. Above this temperature, the fiber begins to loose weight and shrink in coilure diameter and the tension resulting from such shrinkage and weight loss causes non- annealable stress cracks and weak points in the fiber.
• the fiber, tow or yarn may be initially heat treated at the higher temperature range (550°C-1000°C for knitted fabric of staple yarn and up to 1550°C for knitted fabric made of continuous filament tows) so long as the heat treatment is conducted while the fiber is in a relaxed state (spring-like configuration) under an inert, non-oxidizing atmosphere.
• a permanent set spring-like structural configuration is imparted to the fiber.
• the resulting fibers, tow or yarn having such spring- like structural configuration may be used per *-e, or in the case of a knitted cloth, may be deknitted to form a sinusoidal or other multi-curvilinear yarn or tow.
• the yarn, tow or the cloth per se may then be further subjected to a carding or garnetting operation or any of a number of other methods of mechanical treatment known in the art to create an entangled wool-like fluffy material in which, the fibers are separated into an entangled mass of fibers and in which the individual fibers retain their spring-like configuration.
• the fibers of the invention have a density of less than 2.5 gm/cm 3 and/or a Young's modulus of from 7 to 380 GPa.
• the fibers, tow, or yarn, or the knitted cloth or the wool-like fluff produced by a heat treatment at a temperature of no higher than about 550°C, in a relaxed state (which has placed a temporary set spring-like configuration into the fibers, yarn, tow or thread) may then be further heat treated in a relaxed state and under a non-oxidizing atmosphere to a temperature of from 550°C to 1500°C to impart not a permanent set, spring-like structural configuration to the fiber.
• various lower degrees of electrical resistivity are imparted to the fibers, such resistivity being / preferably less than about 10 10 ohm-cm.
• a fused conjugated (benzenoidal) structural configuration is imparted to the fibers, at least at their outer surface, due to the heat treatment of the fibers at these higher temperatures.
• a more extensive developement of the fused benzoidal structure occurs as the heat treatment is carried out at the higher temperatures, particularily at a temperature of from 1000-1550°C.
• the diameter of the fibers is reduced when treated at a higher temperature up to about 1550°C.
• higher temperature treatment results in a gradually increasing brittleness, the fibers still retain their spring-like configuration.
• the carbonaceous precursor materials are of a nature believed to lose their non-carbon moieties upon heating and form a conjugated bond structure within the carbon to carbon backbones which are believed to convert to an aromatic, fused, ring-like form of the graphitic nature carbons.
• the knitted cloth is not heated to a temperature above 1000°C, preferably not above 550°C, prior to carding when a wool- like fluffy material is desired in order to avoid fiber breakage, since at temperatures much above about 1000°C, the fibers become too brittle to survive the mechanical forces of disentanglement necesssary to produce the wool-like fluffy material.
• brittle fibers produced at the higher temperatures of above 1000°C may still be useful as, for example, a structural reinforcement material for various synthetic resinous materials, as a filler material for rendering synthetic resinous materials antistatic, as electrical conductors (e.g. automobile ignition systems), as a thermal insulating material, or the like.
• continuous filaments may be heat treated to a temperature of about 1550 * C and still be carded to prepare a wool-like fluffy product.
• the stabilized fibers, yarn or tow when heat-set into the desired spring-like structural configuration, e.g. by knitting, and thereafter heating at a temperature of from 550°C to 1550°C retain their resilient and reversible, deflectable characteristics in accordance with Hooke's Law. If the yarn or tow has been knitted and heat treated at a temperature between 550 * C. and 1000°C to "perm-set" the spring-like configuration in the yarn or tow, it may then be de-knitted, carded, garnetted or otherwise mechanically treated to convert the deknitted yarn or tow to an entangled wool-like fluffy material which still retains a resilience similar to that found in wool.
• a predetermined length of fiber, yarn or tow made into a spring-like structural configuration in accordance with the above described manner will exhibit a reversible deflection in excess of 1.2 times, generally greater than twice, of its relaxed, non- elongated, spring-like configuration.
• a fiber, yarn or tow which has been provided with a permanently set spring-like configuration can be stretched or elongated to a length of at least 1.2 times of its coiled, i.e. contracted, relaxed spring-like structural configuration length.
• the knitting parameters such as the number of loops per unit length or the number of turns on a rod or mandrel
• the tightness or looseness of the non-linear, coil or curl in the fiber e.g. the loops per centimeter in a knitted cloth, therefor governs the extent of the elongation of the spring-like fiber, yarn or tow.
• the reversible deflection could be much greater than twice the length of a fiber yarn or tow when in a relaxed state, spring-like configuration.
• an assembly e.g. a bundle of fibers is obtained, by spinning a carbonaceous precursor material into a fiber, stabilizing the fiber assembling a multiplicity of mono-filaments or fibers into a tow, and knitting the tow into a cloth.
• the fibers in the cloth are "set", i.e. temporarily formed into a coil-like or sinusoidal structure, by treating the knitted cloth at a temperature of from 150°C to 550°C.
• the fibers in the knitted cloth are formed into a permanently set, spring-like structure at a temperature of from 550 * C to 1550°C and most preferably at a temperature of less than 100°C, under an inert atmosphere and in a relaxed condition.
• the fibers in the knitted cloth may then be carbonized at a temperature in excess of 1000°C to impart other desirable properties into the fibers, noted hereinabove.
• the fiber tow having the spring-likle configuration or even the knitted fabric may be carded, garnetted, or otherwise mechanically treated either before or after treatment at a temperature of less than 1550°C, preferably less than 1000'C., and most preferably at a temperature of below about 650°C, when preparing a wool-like, fluffy material.
• the perm set (550 to 1000°C) fiber, tow or cloth can be further heat treated to a temperature above 1000°C, e.g. up to 3000°C.
• fibers treated at a temperature above 1550°C become extremely brittle and do not readily lend themselves to a deknitting, carding or garnetting treatment. Accordingly, such carding and/or garnetting treatment should be accomplished prior to heat treatment to temperatures above 1000°C for staple yarn, tows, or threads and prior to heat-treatment to a temperature of up to 1550°C for continuous fiber or fiber tows.
• Fibers made from carbonaceous precursor materials normally have a surface area of from 0.5 to 1600 m 2 /gm, preferably less than 15m 2 /gm when produced according to the procedures set forth above. However, it is known that such fibers can have imparted to them a surface area of greater than this by rapidly heating the fibers to a high temperature thereby converting the non-carbon moieties to gases which, on leaving the fiber, disrupt the surface.
• Other techniques known in the art for producing high surface area, high porousity fibers include oxidation of the fiber surface.
• Such high porousity fibers can be prepared from the materials of the present invention by the same techniques after the spring-like structural configuration has been imparted into the fibers.
• the continuous fibers or the yarns or threads of staple fiber may be chopped into discrete lengths and made in to non-woven products employing present day techniques for preparing such non-woven products.
• the deknitted tow was cut into various lengths of from 5 to 25 cm, and fed into a Platts Shirley Analyzer.
• the fibers of the tow were separated by a carding treatment into a wool-like fluff, that is to say, the resulting product resembled an entangled wool-like mass or fluff in which the fibers had a high interstitial spacing and a high degree of interlocking as a result of the coiled and spring-like configuration of the fibers.
• the fiber lengths of each such treatment were measured and the results of these measurements set forth in Table I.
• a fabric was knitted from a 3K or 6K PANOX (R.K. Textiles) continuous stabilized filament tow on a Singer flat bed knitting machine and heat treated at the temperatures set forth in Table II and under an inert atmosphere of nitrogen. The fabric was then deknitted and the tow having a spring-like structural configuration fed directly into a carding machine. The resulting wool-like mass was collected onto a rotating drum and had sufficient integrity to enable it to be easily handled. The length of the fibers ranged from 2 to 15 cm.
• the wool-like mass treated at a temperature of 950°C was highly conductive and had a resistance of less than 75 ohms at any probe length taken at widely separated distances up to 60 cm in the wool-like mass.
• a 3K PANOX stabilized tow was knitted on a Singer flat bed knitting machine at a rate of 4 stitches/cm and was then heat treated at a temperature of 950 * C and under an inert atmosphere of nitrogen.
• the cloth was deknitted and the tow (which had a coil elongation or reversible deflection ratio of greater than 2:1) cut into 7.5 cm lengths.
• the cut yarn was then carded on a Platt Minature Carding machine to produce a wool-like fluff having fibers ranging from 3.5 to 6.5 cm in length with an average length of about 5 cm.
• the wool-like fluff had a high electrical conductivity over any length of up to 60 cm tested.
• Example 3 In a similar manner to Example 3 a portion from the same knitted cloth was heat treated at a temperature of 1550°C and under an inert atmosphere of nitrogen. The cloth itself and the deknitted tow had a very high electrical conductivity. On carding 15 cm lengths of cut tow, a fluff was obtained which had fibers of lengths 2.5 to 9.5 cm with average lengths of 5 cm. Thus, carding of a deknitted, continuous filament tow, fabric which has been subjected to a temperature of above 1000°C is still capable of producing a wool-like fluffy product.
• a staple 2 ply singles 10's stabilized polyacrylonitrile PANOX yarn was knitted into a tubular sock at a rate of 4 loops per cm and thereafter heat treated at a temperature of 1550°C under an inert atmosphere of nitrogen and the yarn was then cut into 10 cm lengths.
• the cut yarn was carded in a carding machine.
• the resulting product was collected with difficulty. Only short fibers having a length of from 0.5 to 1.25 cm were obtained along with a high level of dust. The difficulty of fiber recovery resulted from the high degree of twist and fiber entanglement which is typically found in spun yarns. Similar results were obtained when this example was repeated starting with a similar spun yarn sample of Grafil-01 obtained from Hysol-Grafil Ltd., Coventry, England.
• the specific resistivity of the fibers was calculated from measurements made on each sample using a measured average of six measurements, one made from fibers removed at each corner of the sample and one made from fibers removed from each edge, approximately at the middle of the sample.
• the results are set forth in Table IV following:
• the carbonized and permanently set fibers of the invention when treated at temperatures sufficiently high to render the fibers electrically conductive and yet sufficiently low where the fibers still exhibit resilient, flexible, and non- brittle characteristics, are particularly suitable for blending with standard carpet fibers or yarn to produce a yarn having static dissipation properties.
• a carpet/yarn blend may incorporate at least 0.25 weight percent carbonized fibers in the carpet yarn.
• the weight ratio of synthetic carpet fibers to carbonized fibers is preferably greater than 100:1 to 200:1.
• a carpet employing the carbonized fibers of the invention exhibited static discharge properties to 0 percent of an applied electrostatic charge in less than 1 second.
• Monsanto 1879 nylon (trilobal) staple was blended with 0.5 percent by weight of a conductive fiber prepared in accordance with the present invention.
• the conductive fiber was prepared by heating an oxidatively stabilized polyacrylonitrile multifilament fiber tow which had been knitted into a cloth, heat treated at about 1500°C, de-knitted and cut into staple approximately 18 cm in length.
• the blended staple was carded and the resulting sliver was pin drafted three times, recombination ratios were 10:1, 3:1, and 5:1, respectively.
• the resulting drafted sliver was spun into a single ply yarn with an average twist of about 4.75.
• the resulting carbonaceous fiber containing singles yarn was plied with a nylon yarn made in the same fashion but containing no carbonaceous fiber.
• the 3.00/2 ply yarn which was heat set on a Suessen heat setting apparatus was thereafter tufted into a 1/8 inch (3 mm) gauge, 27 on (765 gm), 9.5 mm pile height carpet (a cut loop form) with approximately 3 stitches per cm.
• the ratio of carbonaceous fiber to yarn containing no carbonaceous yarn in the tufting operation was 1:5, respectively.
• a portion of the carpet was backed with a commercial non-conductive latex carpet backing.
• the resulting carpet was tested for static discharge properties by charging the carpet to 5000 volts while in an atmosphere having a relative humidity of less than 20 percent.
• the static charge was dissipated to 0 percent of original charge in less than one second, and some of the samples discharged in less than 1/2 second.
• the standard for the industry is a discharge to 0 percent in 2 seconds or less.
• Example 6 100 grams of the same precursor acrylonitrile fiber tow as described in Example 6 was used. However, the precurser fiber was heat treated after knitting at a temperature of 950°C. All other aspects of handling the carbonaceous material were the same.
• the carbonized fiber was blended with 45 kg of the Monsanto 1879 nylon yarn as in Example 6.
• the resulting yarn contained 0.02 percent carbonized fibers which were substantially evenly distributed throughout the yarn.
• the yarn was tufted to prepare a carpet in a similar manner to Example 6. Thus, each tufted end has the carbonized fibers. Results were similar to the results obtained in Example 6.
• Knitted yarn or fiber tows which have been heat treated to a temperature above 1000°C, and thus been rendered electrically conductive, have also found special utility in the manufacture of electrodes for a non-aqueous secondary energy storage device such as described in U.S. Application Serial No. 558,239 filed December 5, 1983, entitled Energy Storage Device by F.P. McCullough and A. F. Beale, Jr., as well as Application Serial No. 678,186 filed December 4, 1984, entitled Secondary Electrical Energy Storage Device and Electrode Therefor.

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• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Textile Engineering (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Inorganic Fibers (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Nonwoven Fabrics (AREA)
• Chemical Treatment Of Fibers During Manufacturing Processes (AREA)

Applications Claiming Priority (4)

Publications (3)

Family

ID=27110981

Family Applications (1)

Country Status (8)

Cited By (16)

Families Citing this family (12)

Family Cites Families (8)

• 1986
  • 1986-04-17 JP JP61502457A patent/JPH0670286B2/ja not_active Expired - Fee Related
  • 1986-04-17 KR KR1019860700908A patent/KR890000129B1/ko not_active Expired
  • 1986-04-17 BR BR8606634A patent/BR8606634A/pt active Search and Examination
  • 1986-04-17 CA CA000506941A patent/CA1284858C/fr not_active Expired - Fee Related
  • 1986-04-17 WO PCT/US1986/000802 patent/WO1986006110A1/fr not_active Ceased
  • 1986-04-18 DE DE8686302959T patent/DE3686504T2/de not_active Expired - Fee Related
  • 1986-04-18 EP EP86302959A patent/EP0199567B1/fr not_active Expired - Lifetime
  • 1986-04-18 AU AU56359/86A patent/AU590879B2/en not_active Ceased
• 1989
  • 1989-11-15 JP JP1295171A patent/JPH0663138B2/ja not_active Expired - Lifetime
  • 1989-11-15 JP JP1295169A patent/JPH0327121A/ja active Pending
  • 1989-11-15 JP JP1295170A patent/JPH0663137B2/ja not_active Expired - Lifetime

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