MXPA96006745A

MXPA96006745A - Fiber birregional flexible resistant to ignition, articles made from birthage fibers and method of fabricac

Info

Publication number: MXPA96006745A
Application number: MXPA/A/1996/006745A
Authority: MX
Inventors: P Mccullough Francis
Original assignee: Mccullough Francis Patrick
Priority date: 1995-04-25
Filing date: 1996-04-25
Publication date: 1998-01-01

Abstract

The present invention relates to a biregional fiber comprising an inner core region of a thermoplastic polymer composition, and a surrounding outer shell region of a thermoset carbonaceous material, wherein the fiber is resistant to ignition, and has an index value. of limited oxygen greater than

Description

FLEXIBLE BIRTHRIGGLE FIBER IGNITION RESISTANT, ARTICLES MADE FROM BIREGGIAL FIBERS, AND MANUFACTURING METHOD FIELD OF THE INVENTION The present invention relates to a flexible bi-regional fiber resistant to ignition, derived from a precursor fiber preferably having a homogeneous polymeric composition throughout the cross section of the precursor fiber, wherein the fiber biregional resistor to ignition has an inner core region of a thermoplastic polymer composition, and a surrounding outer shell region of a thermosetting carbonaceous material. The invention also relates to a biregional precursor fiber having an inner core region of a thermoplastic polymer composition, and a surrounding lining region stabilized to oxidation, a method for the manufacture of bi-regional fiber, and articles made from a multiplicity of these bi-regional fibers. In both the biregional precursor fiber and in the bi-regional fiber, the ratio (r: R) of the radius of the core region (r) with respect to the total radius (R) of the biregional fiber, is 1: 4 to 1: 1.05, preferably from 1: 3 to 1: 1.12. Preferably, the biregional precursor fiber of the invention has a density of 1.20 grams / c to 1.32 grams / cm3, and a breaking angle at about 17 to about 23 degrees, while the biregional fiber of the invention is resistant to ignition, and has a LOI value greater than 40. The bi-regional fiber is flexible and lacks the brittleness normally associated with the carbon and graphite fibers of the prior art. Bi-regional fiber has a twisting angle ~ "" "" to the break of 4 to 13 degrees, a density of 1.45 to 1.85 grams / cm3, and as high as 1.87 grams / cm3, a bending stress value from more than 0.01 to less than 50 percent, preferably from 0.1 to 30 percent, and a Young's modulus from less than 1MM psi (< 6.9 GPa) up to 50 MM psi (345 GPa), preferably from 1MM psi to 30MM psi (207 GPa).

BACKGROUND OF THE INVENTION The linear and non-linear carbonaceous, elastic and flexible fibers are now well known in the art.

Representative of non-linear carbonaceous fibers are in U.S. Patent No. 4,837,076, issued June 6, 1989 to McCullough et al. The fibers are produced by melted or wet spinning fibers, from a composition The thermoplastic polymer is then stabilized by treating it in an atmosphere containing oxygen, and at an elevated temperature for a predetermined period of time. The oxygen stabilization treatment of the fibers is carried out to the extent that the entire polymer composition of the fibers, when seen in cross section, is oxidized. Although the stabilization process depends to some degree on the diameter of the fibers, the composition of the precursor composition -'--. polymer, the level of oxygen in the atmosphere, and the The temperature of the treatment, the process is extremely time consuming and expensive to achieve a complete stabilization of the fibers through their entire cross section. Traditionally, the stabilization treatment of polymer fibers under oxygen is extended during At least several hours to more than 24 hours, to completely lose the fibers with oxygen, and to achieve a sufficient stabilization of the fibers in preparation for a subsequent carbonization of the stabilized fibers to produce carbonaceous fibers for commercial end uses. The Encyclopedia of Polymer Science an Engineering, Volume 2, an iley-Interscience Publication, 1985, pages 641-659, reports that "current conventional processing technology requires 1 to 2 hours for adequate stabilization" of the fibers, page 658. No description is given other processing method suitable for large or "heavy" 320k skeins. Also, in "High Performance Fibers" III, published by Battelle, esp., In the chapter entitled "Process Technology - Oxidation / Stabilization", page 149 et seq., It is reported that oxidation and cyclization take place between 150 ° C and 300 ° C. ° C, and that "the reaction must take place throughout the fiber and should not be confined to the surface of the fiber". In accordance with the above, the long stabilization treatment employed in the present conventional processes, reduces the output produced from stabilized fibers, requires a substantial capital investment and, therefore, is extremely expensive and a major obstacle to making the process it is advisable for greater commercial exploitation, that is, an extended commercial use of the fibers at a lower cost. It is also reported that, if electrically heated oxidation chambers are used, the chambers must be substantially larger than the furnaces used in the subsequent carbonization step, thus resulting in a substantially higher cost of capital. In addition, in the United States Patent of North American Number 4,837,076 it is taught that conventionally stabilized fibers (stabilized precursor fibers) are subsequently formed in the form of a coil and / or in a sinusoidal shape, by weaving or spinning a skein of fiber in a fabric. The woven fabric thus formed is subsequently heat treated in a relaxed and unstressed condition, and in a non-oxidizing atmosphere, at a temperature of 525 ° C to 750 ° C, and for a sufficient period of time to produce a thermofix reaction induced by heat, where an additional crosslinking and / or cross-chain cyclization occurs between the original polymer chains. The carbonization treatment of the fibers is carried out to the extent that all the stabilized material is carbonized by oxidation of the precursor fibers, when seen in cross section. In a specific manner, there is no residual portion of the fiber material stabilized by oxidation in a thermoplastic condition. In Example 1 of U.S. Patent No. 4,837,076, portions of a stabilized woven fabric were heat set at temperatures of 550 ° C to 950 ° C for a period of 6 hours. The more flexible fibers, and the fibers that are subject to the least breakage of the fiber, due to the brittleness when subjected to textile processing, were obtained in the fibers that had been heat treated at a temperature of 525 ° C to 750 ° C. The resulting skeins of fibers, obtained by unraveling the fabric, and having heat setting, ie, a thermosetting non-linear structural configuration, can then be subjected to other treatment methods known in the art to create an opening, a process wherein a thread or the skeins of fibers of the fabric are separated into a foamed material in the form of entangled wool, wherein the individual fibers retain their configuration in the form of a coil or sine, giving a body in the form of a bast or a wadding a considerable upheaval. U.S. Patent No. 4,837,076 also discloses that, at a treatment temperature greater than 1,000 ° C, the stabilized precursor fibers become graffitic and highly electrically conductive to the point where they begin to approach the conductivity of a metallic conductor. These graphite fibers find a special utility in the manufacture of electrodes for energy storage devices. Since the graphitization of the stabilized fibers is carried out at a temperature and for a period of time such that all the stabilized polymer material of the fiber, when seen in cross section, is graphitized, the process, especially at the highest temperatures, is extremely slow and energy consuming, and intense in equipment and therefore, very expensive. Graphitization of stabilized fibers by oxidation is generally desired, in order to produce higher tensile modulus properties in the fibers. However, in High Performance Fibers II, published by Battelle, Copyright 1987, esp. , in the chapter titled "Process Technology - Gaphitization", pages 158 and 159, it is reported that "the breaking of the fibers is a problem that has not been solved", and that "the most serious inconvenience of these fibers of high resistance to traction, is its low ratio of stress to failure, which means that they are very brittle. " Moreover, it is also said that the process is expensive, due to the "high capital cost of the equipment and the large amount of electrical energy required to reach the temperature necessary for the graphitization of the fibers (from 2000 ° C to 3000 ° C). through its entire cross section. " Fibers which are generally referred to as "two-component fibers or composite fibers", "two-component fibers", "bilateral fibers" and "core-liner fibers" are commonly known in the art. Definitions of these terms can be found in "Man-Made Fiber and Textile Dictionary", Hoechst Celanese Corporation, 1990, pages 14, 15, 32 and 139. A two-component or composite fiber is defined as a fiber composed of two or more types of polymer in a lining-core or side-by-side relationship (bilateral). The fibers of two constituents are defined as fibers that are extruded from a homogeneous mixture of two different polymers, where these fibers combine the characteristics of the two polymers into a single fiber. Bilateral fibers are two generic fibers or variants of the same generic fiber extruded on one side per ratio. Liner-core fibers are two-component fibers, either of two types of polymer or two variants of the same polymer. One polymer forms a core, and the other polymer of a different composition surrounds it as a liner. Fibers of two components have also been generally described in U.S. Patent No. 4,643,931, issued February 17, 1987 to F.P. McCullough and collaborators. These fibers are mixtures of a small amount of conductive fibers in a thread, to act as an element. of electrostatic dissipation. Fiber manufacturers also routinely manufacture conductive fibers by incorporating into a hollow fiber, a carbon or graphite core containing a thermoplastic compound, or by coating a fiber with a liner made of a thermoplastic compound containing carbon or graphite. U.S. Patent Number 5,260,124, issued November 9, 1993 to J.R. Gaier describes a hybrid material comprising a high-strength carbon fiber or graphite fabric, a layer of graphitized carbon disposed on the fibers, and an interlayer in the layer. In the manufacturing process, the high-strength carbon fiber or graphite fabric from Gaier is covered by vapor deposition with a layer of porous graphite to form a bidirectional fabric structure. In contrast to Gaier, the fibers of the invention are "bi-regional", and are not carbonized or graphitized through their cross section to form a high strength fiber, nor are the bi-regional fibers resistant to ignition of the present invention. They are covered with a layer of graphitized carbon, forming a composite structure. The core region of the fiber of the invention always remains thermoplastic, my entering, that the fiber lining region is stabilized by oxidation and is thermoplastic, or is carbonaceous and thermosetting. Still, the biregional fiber resistant to ignition of the invention does not require an intercalation treatment in the outer graphite layer. The electrical energy storage devices, particularly batteries, which employ fibrous carbon or graphite electrodes, and which operate in a non-aqueous electrolyte at room temperature, are known from US Pat. No. 4,865.31, issued September 12, 1989 to FP McCullough and collaborators. The patent generally discloses a secondary battery comprising a housing having at least one cell placed in the housing, each cell comprising a pair of electrodes made of a multiplicity of electrically conductive carbon fibers, a foraminous electrode separator for electrically isolating the electrodes of contact with each other, and an electrolyte comprising an ionizable salt in a non-aqueous fluid in each cell. In the Patent of the United States of North America Number 4,830,938 of F.P. McCullough et al., Issued May 16, 1989, describes a similar electrical storage device. This patent discloses a shared, bipolar, carbonaceous, fibrous electrode that is capable of carrying a current from a cell to an adjacent cell without a current collector frame associated therewith. None of the patents of McCullough and aforementioned co-workers describe the use of bi-regional ignition-resistant fibers having an inner core region of a thermoplastic, psi-thermic composition, and a surrounding outer lining region of a thermosetting carbonaceous material. The bi-recirculating fibers of the invention are particularly suitable for use as electrodes in secondary energy storage devices, primarily in view of their substantially greater flexibility, and their lower cost. In general, the bi-regional fibers of the invention are distinguished on the different types of fibers of the prior art, in that the biregional fiber is preferably produced from a homogeneous polymer composition, ie, a single polymer composition, preferably a acrylic polymer, where an outer region of the fiber is * '• Stabilizes by oxidation, and then carbonizes to form two visually distinct regions in the fiber, seen in cross section, ie, typically a translucent or slightly colored inner core region, and a black outer lining region. In the case of a biregional precursor fiber, the fiber comprises a thermoplastic inner core and a thermoplastic stabilized outer lining, while in the case of biregional fiber resistant to the ignition, the inner core is thermoplastic, and the outer torus is thermoframed and carbonized. When the bi -regional ignition resistant fiber of the invention is manufactured from a homogeneous polymer composition, preferably an acrylic polymer, it is not there is a limit or discontinuity between the inner core and the lining stabilized by oxidation or external carbonization. The term "homogeneous polymer composition" used in the The present invention includes homopolymers, copolymers and terpolymers, and does not include fibers containing two or more polymers of different compositions and crystallinity coefficients. In contrast, discontinuities occur in two-component fibers 6 of two components, where two polymers of different compositions are used in a side-by-side, or core-shell relationship. These discontinuities or limits are presented between the layers of the different polymeric compositions, due to their different crystallinity coefficients. This also applies to different polymeric compositions that intermix with each other. In the case of a core / liner fiber, the outer lining layer is formed very similar to a skin layer, and is separate and distinct from the inner core, thus forming a physical boundary or a discontinuity between the inner core and the outer skin layer. More specifically, to see a cross-sectional surface of a two-layer or core-liner fiber (generally co-extruded), the inspection of the surface from an outer periphery to the center of the fiber surface would pass from one type of composition to another. polymer that forms the outer lining layer, through a limiting layer or discontinuity in the core having another polymer composition of different crystallinity. As indicated above, polymers having different compositions, also have different coefficients of crystallinity and melting points. For example, polyacrylonitrile will undergo a melting point transmission at a temperature scale of 320 ° C a.) Jü ° c. This represents a relatively high melting point for polymers, and is characteristic of rigid chains. Both nylon 6,6 and PET fibers melted at 265 ° C, and polyolefins, such as polyethylene and polypropylene, melt at around 135 ° C and 165 ° C, respectively. According to the above, although the inner core and the outer lining of the biregional fiber of the invention form two visually distinct regions, when viewed in cross section, they do not form a physical boundary or a discontinuity between the core and the lining, it is say, the regions with continuous. The only homogeneous polymeric composition that is used in the manufacture of fiber "- biregional ignition resistant, is a conventional acrylic polymer, ie homopolymers, copolymers and terpolymers of acrylonitrile, where copolymers and terpolymers contain at least 85 mole percent of acrylic units, and up to 15 percent by weight. one hundred mole of one or more vinyl monomers copolymerized therewith, or optionally, a subarylic polymer, as described hereinafter.

DEFINITIONS - The terms "bi-regional fiber", "biregional fiber 0 resistant to ignition" and "BRF" are used interchangeably herein, and in general refer to a fiber that is preferably produced from a single homogeneous polymer composition, for example, acrylic polymers, including homopolymers, copolymers, terpolymers and the like, comprising an inner core region of a thermoplastic polymer composition, and a surrounding outer shell region of a thermosetting carbonaceous material. However, it is entirely possible, and well within the skill of the skilled person, to produce the bi-regional fiber from two or more polymers of different compositions and crystallinity coefficients, particularly where additional operating properties are desired. Specifically, the biregional fiber may be produced in a core-liner configuration, wherein the liner is of an acrylic composition or other suitable carbonizable precursor composition, and the core is composed of a compatible polymer, such as a modacrylic or subacrylic polymer, PVC (polyvinyl chloride), modified polyvinyl chloride, or the like. It will be readily noticed - by the expert that the stabilization and carbonization of a core-liner fiber can result in an outermost region of a thermoset carbonized material, an intermediate transition region of a stabilized thermoplastic polymer, both of which are derive from a first polymeric composition, and a thermoplastic inner core composed of a second polymeric composition, different from the first polymeric composition. This core-liner fiber, therefore, could consist of an external carbonaceous lining resistant to ignition, an intermediate region, and an inner core of a thermoplastic composition to impart flexibility and tenacity to the fiber. The term "homogeneous", when applied to a homogeneous polymer composition, refers to a composition that is uniformly the same, ie, it is formed of a single polymer composition having a single coefficient of crystallinity and melting point. The terms "bi-regional precursor fiber" or "BRPF" are used interchangeably herein, and are applied to a fiber that is preferably derived from a single homogenous polymer composition, although it is also intended to be within the scope of the invention include mixtures comprising a homogeneous polymer composition having particles in inert submicrons, or the like, distributed throughout the composition. The biregional precursor fiber of the invention is distinguished from the present state of the art, by having an inner core region of a thermoplastic polymer composition and an outer oxidatively stabilized outer lining region. The stabilized outer lining region of the fiber has a high softening temperature up to no softening temperature, and is able to withstand the higher temperature conditions of carbonization without detrimentally affecting the fiber, i.e. carbonization of the fiber it does not affect the integrity of the thermoplastic composition of the inner core, since it is protected by the surrounding stabilized outer lining region. The biregional precursor fiber of the invention differs in addition to the fibers completely stabilized by oxidation (OPF) of the prior art, by its increase in the angle of twisting to breaking, which is 17 to 25 degrees, without exhibiting any tear. In contrast, fibers stabilized by conventional oxidation, tear at a twisting angle at break of 15 to 17 degrees. The biregional precursor fiber of the invention, in effect, becomes a "biregional precursor fiber", as defined, for the preparation of biregional fiber, that is, a biregional fiber resistant to ignition that has a region of carbonized outer lining. . The oxidation and cyclization of the polymer fiber generally takes place at a temperature of between 150 ° C and 350 ° C, and for a sufficient time (more than 5 minutes, but typically less than 180 minutes) to produce an external lining of material polymeric thermoplastic stabilized by oxidation of any desired thickness. It will be understood that the stabilization of a polymer composition can be carried out by other elements than "oxidation", as for example, by chemical oxidants applied at lower temperatures. The terms "ignition resistant" or "non-flammable" used herein, refer generally to the property of a sample that will not suffer combustion in the air upon being subjected to an ignition source (a source of flame) to a temperature of 1000 ° C or higher. The resistance to ignition is determined by a LOI test, which is also known as the "oxygen index" or "limited oxygen index" (LOI) test. With this procedure, the oxygen concentration in 02 / N2 mixtures is determined, in which a vertically mounted sample, when ignited at its upper end, continues to burn. The size of the sample is 0.65 to 0.3 centimeters wide, and it has a length of 7 to 15 centimeters. The limited oxygen index value is calculated according to the equation: LOI = [02] X 100 [02 + N2] The term "carbonaceous lining region", used herein, is applied to the outer lining region resulting from the biregional fiber produced by the carbonization of at least a portion of the stabilized outer region of a bi-regional precursor fiber that is made in an inert atmosphere at a high temperature, and where existing carbon-to-carbon bonds are maintained, and new carbon-to-carbon bonds are established while oxygen, hydrogen and nitrogen are removed from the molecular structure of the outer region, and without cause complete carbonization through the entire cross section of the fiber. Depending on the particular end use desired, the outer carbonaceous lining region of the fiber can be carbonized to a carbon content greater than 68 percent and up to graphitization, where the carbon content exceeds 98 percent by weight. The term "carbon fiber" is known, and is generally applied to a fiber that has a uniform carbon content across an entire fiber cross section of more than 92 percent, while the term "graphite fiber" "or" graffitic fiber "is generally applied to a fiber having a uniform carbon content across an entire fiber cross section greater than 98 percent. it is intended herein that the term "carbonaceous" is applied to the outer lining region of the biregional ignition resistant fiber, BRF, of the invention, which has been carbonized to a carbon content greater than 68 weight percent . The term "thermofixed", used herein, is applied to polymeric compositions that have undergone a heat-induced cross-linking reaction of the molecular constituents to "set" the polymer in an irreversible manner. The thermofixed polymer essentially has no tendency to melt or soften under the conditions of carbonization, and will not exhibit breakage of the outer carbonized region of the fiber, for example, when the fiber is subjected to a twisting angle greater than 5 degrees. (as defined later in this). The angle of twisting to the break varies, of course, and depends on the degree of carbonization, ie, the carbon content of the external carbonized lining, and the carbonization depth in the fiber. The breaking angles at break for different types of bi-regional fibers of the invention are stipulated in the following Table II. The term "bending stress", as used herein, is as defined in Physical Properties of Textile Fibers by .E. Morton and J.W.S. Hearle. The Textile Institute, Manchester, England (1975), pages 407-409. The percentage of bending tension on a fiber can be determined by the equation S = (r / R) x 100, where S is the percentage of bending tension, r is the radius of the fiber effective in the cross section, and R is the bend radius of the bend. That is, if the neutral plane remains at the center of the fiber, the maximum percentage of tensile stress, which is positive on the outside, and negative on the inside of the fold, is equal (r / R) x 100, at a circular cross section of the fiber. The term "flexible", used herein, can be applied specifically to bi-regional fibers having a fold-over value from more than 0.01 to less than 50 percent, preferably from 0.1 to 30 percent. The term "breaking angle, a", as used herein, is as defined in Physical Properties of Textile Fibers by W.E. Morton and J. .S. Hearle. The Textile Institute, Manchester, England (1975), pages 421-425. If a fiber gets twisted enough, it will eventually break. The breaking point in which this is presented, is called the "break to break". The number of turns until the break is inversely proportional to the diameter of the fiber. To obtain a property characteristic of the material of the fiber, the angle of twisting to the -rompimiento, can be used. This is the angle through which the outer layer can be twisted until it tear, and is given by the formula: so a = p d Tb where d = diameter of the fiber, and Tb = twist to breaking in turns per unit length. The term "tear sensitivity", used herein, generally applies to the tendency of a fiber to become fractured along a plane in the cross section of a fiber, as a result of such forces, such as caused by the twisting. In practical terms, when the fibers are subjected to certain textile operations, such as the stretching operation in a yarn folding process, the stretching rollers exert a significant tear on the fibers being stretched. Tear-sensitive fibers exhibit extensive damage, if not complete breakage, while tear-resistant fibers do not exhibit significant breakage at this step in the process. Conversely, the term "tear resistant" is applied to fibers that do not tend to break significantly when exposed to textile process operations, such as stretching or twisting, that exert significant tear stresses * on the fibers being processed. The term "volume resistivity", used in the present, is applied to generate the effective resistivity of a biregional fiber resistant to ignition, taking into account the specific resistivity of the composition of each region, and the proportion of area represented by each region, that is, the particular proportion (r: R), as applied to a fiber with previously selected properties determined. The term "polymeric composition", used herein, includes the polymeric materials defined in Ha Law Condensed Chemical Dictionary, Eleventh Edition, page 938.

The term "curl", as used herein, is applied to the waviness or non-linearity of a fiber or skein of fiber, as defined in "Man Made Fiber and Textile Dictionary" by Celanese Corporation. The term "fiber assembly", used herein, is applied to a multiplicity of bi-regional precursor fibers or bi-regional fibers that are in the form of a yarn, a wool in the shape of a skein, a wadding, a mat, "" a fabric or felt, a mixture of bi-regional precursor fibers or bi-regional fibers with other natural or polymeric fibers, a sheet formed by compression, a mesh or panel of the fibers, generally with a small percentage of less than 10%. 100% of a binder, especially binder fibers, a woven or spun fabric, or the like. The term "cohesion" or "cohesiveness", used herein, as applied to the force that holds the fibers together, especially during yarn manufacture.

It is a function of the type and amount of lubricant used, and fiber curling. The term "aspect ratio" is defined herein as the ratio of length to diameter (1 / d) of a fiber. All percentages given herein are "per 25 weight percent", unless otherwise specified.

SUMMARY OF THE INVENTION The present invention comprises a major departure from the current state of the art, in that it is now no longer necessary to oxidatively stabilize polymer fibers 5 completely through their entire cross section, but that these fibers can now be made in oxidatively stabilized bi-regional precursor fibers (BRPF), limiting the degree of stabilization to an external region of the fibers, '' in such a way that the time it takes to stabilize Indeed, the fibers are substantially reduced, resulting in a substantial reduction in the manufacturing cost of the biregional precursor fiber. "Effectively stabilized" means that the fiber has the characteristics of a fully stabilized fiber, and can be exposed to the highest temperatures used in the carbonization step. In a corresponding way, in the process of the invention, it is now no longer necessary to completely carbonize bi-regional precursor fibers, but what can be reduced or the carbonization time by carbonizing at least a portion of each fiber that has been oxidatively stabilized, reducing this way the time and energy requirements for the manufacture of bi-regional fibers, while improving the key performance characteristics of the fiber, particularly its flexibility, elongabi.li.dad and sensi.bi.li.dad to tear. It is not essential that the carbonization is carried out to the extent that it is exactly coincident with the extension of the stabilization. In other words, the carbonization of the bi-regional precursor fiber may be a little smaller than the extension of the stabilized outer region, or it may be a little larger than the extension of the stabilized outer region. In the latter case, it has been found that the carbonization of the unstabilized thermoplastic inner core region does not result in an uncontrollable exothermic reaction, and does not affect in any way the integrity of the finished fiber. Accordingly, it is a particular object of the invention to provide an ignitable biregional fiber resistant to ignition, preferably derived from a precursor fiber made from a single homogeneous polymer composition, this biregional fiber having an inner region of a thermoplastic polymer core. , and a surrounding outer region of a thermoset carbonaceous liner. It is another object of the invention to provide a flexible biregional precursor fiber, derived from a homogeneous polymer composition, and wherein the fiber has, in cross section, an inner region of a thermoplastic polymer core, and a surrounding outer region of a liner oxidatively stabilized thermoplastic.

It is another object of the invention to provide a process for the manufacture of a biregional precursor fiber stabilized by oxidation, by treating a fiber preferably made of a homogeneous polymer composition in an oxidizing atmosphere, and for a sufficient period of time and at a temperature to oxidize an outer region of the fiber, to form an external liner stabilized by oxidation, this fiber having an inner core region consisting of a non-oxidized thermoplastic material. It is another object of the invention to provide a process for the manufacture of the bi-regional fiber of the invention, by treating a fiber preferably made of a single homogeneous polymer composition in an oxidizing atmosphere, for a period of time and at a temperature sufficient to oxidizing an outer region of the fiber, to form an external lining stabilized by oxidation, and then heating the stabilized precursor fiber by oxidation in a "non-oxidizing atmosphere, at a temperature and for a sufficient period of time (greater than 10 seconds, but less than 300 seconds) to carbonize the stabilized region by external oxidation of the fiber, this fiber having an inner region of a non-oxidized thermoplastic core, and a surrounding outer region consisting of a thermo-hardened carbonaceous lining.

It is a further object of the invention to provide different assemblies from a multiplicity of the novel fibers of the invention, ie bi-regional precursor fibers or bi-regional fibers, or mixtures thereof, including these assemblies, non-spun assemblies, such as, for example, a wool in the form of skein, a wadding, fabric, felt and the like, mixtures of bi-regional fibers with other natural or polymeric fibers, a sheet or panel formed or densified by compression of bi-regional fibers, containing usually a small percentage of less than 10 percent of a polymeric binder, especially binder fibers, or a woven or spunbond, and the like. In any of these assemblies or structures, the biregional precursor fiber or the bi-regional fiber may be linear or curly, or a mixture thereof. It is also an object of the invention to provide a multiplicity of crimped bi-regional fibers or the invention, in the form of a wool such as tow or wadding, with a substantial lift, to be used as a fire-resistant thermal insulation for buildings, such as residential buildings , of offices or public, etc. Although these thermal insulation fibers are preferably bi-regional fibers, they can also be bi-regional precursor fibers, or a mixture of bi-regional fibers and bi-regional precursor fibers. Depending on the degree of carbonization of the lining of bi-regional fibers, that is, electrically non-conductive, semiconductor or conductive, the fibers can also be used for other different purposes, such as for an electromagnetic or antistatic protection material; as a fire-resistant thermal insulation and as a sound-absorbing material in aircraft, or as a fire-blocking panel in vehicles, * - such as automobiles, aircraft, boats, etc. The 0 bi-regional fibers that are graphitized and highly electrically conductive (BRF-B) are especially suitable as electrodes in secondary energy storage devices. It is another object of the present invention to mix the fibers of the invention with other natural or synthetic fibers. These fibers are particularly useful in the preparation of yarn for the manufacture of textiles. Bi-regional precursor fibers or linear bi-regional fibers, or non-linear or crimped fibers, when mixed with other natural or synthetic fibers, are useful in the form of a wool like tow that can be used in cloth articles., such as, for example, jackets, quilts or sleeping bags. In another object of the invention, bi-regional fibers or bi-regional precursor fibers can be used as a reinforcing material in a polymeric matrix, forming a fiber-reinforced composite The fibers can be linear, non-linear fibers or a mixture of the linear and non-linear fibers, and can be applied to at least one surface of the polymeric matrix, or they can be dispersed through the polymeric matrix When the bi-regional fibers are applied to the surface of a polymeric panel, such as , for example, a panel formed from a polystyrene polymer, as little as about10 percent by weight of the fibers, based on the total weight of the panel, provides the panel with fire resistance. When bi-regional fibers are distributed throughout the polymeric panel, in an amount of up to 95 percent by weight, the fibers provide a compound that has better resistance to fire, as well as resistance to vibration and impact, and adhesion. It is a particular object of the invention to provide terminal and / or polar electrodes for secondary energy storage devices, such as batteries, including lithium ion cells, using the novel bi-regional fibers of the invention. The invention also relates to several different types of batteries that use at least one of these electrodes, and to a lithium-ion battery that uses a bipolar pseudo-electrode that use the novel bi-regional fibers of the invention, having a portion thereof coated with a lithium salt of a metal oxide. It is a further aspect of the invention to provide the bi-regional fiber of the invention with a conformational silicone coating, in order to improve the fiber resistance characteristics. It is also an aspect of the invention to provide an assembly from a multiplicity of bi-regional fibers of the invention, and to coat the assembly with a coating of hydrophobic material, in order to cause the assembly to float. It is a further object of the invention to employ a multiplicity of the bi-regional fibers of the invention, in the form of a wadding, fabric or the like, as an electromagnetic protection material. Optionally, the protection material can be incorporated into a polymeric matrix to form a panel. Other objects of the invention, not specifically mentioned hereinabove, will become clearer from a reading of the detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a biregional fiber resistant to ignition, generally of a circular cross section, of the invention. Figure 2 is a cross-sectional view of a biregional fiber resistant to ignition, trilobal cross-section, preferred of the invention. Figure 3 is a schematic view of a flow diagram of the steps of the process for the manufacture of the bi-regional fibers resistant to the ignition of the invention, and different end uses for the bi-regional fiber resistant to novel ignition.

DETAILED DESCRIPTION OF THE INVENTION In the manufacture of carbonaceous fibers, the stabilization of the polymer fibers is generally conducted in an oxidizing atmosphere, and under tension, at a moderately elevated temperature of, typically, 150 ° C to 350 ° C for the fibers of PAN (polyacrylonitrile), and for a sufficient period of time to achieve a complete permoration of oxygen through the entire fiber, and then heat treated the "oxidized polyacrylonitrile fiber" (OPl) in a non-oxidizing atmosphere, usually low tension, at a temperature greater than 750 ° C, to produce a fiber that is carbonized through a whole cross section of the fiber, i.e., through the fiber material. Fibers that are treated at a temperature greater than 1500 ° C, typically have a carbon content greater than 92 percent, and are characterized as carbon or graphite fibers having a high tensile strength. The stabilization of the fibers involves: (1) a crosslinking reaction by oxidation of the attached molecular chains, as well as (2) a cyclization reaction of the pendant nitrate groups to a condensed heterocyclic structure. The reaction mechanism is complex, and can not be easily explained. However, it is believed that these two reactions occur concurrently, and may be competing. The cyclization reaction is of an exothermic nature, and must be controlled if you want to preserve the fibrous nature of the acrylic polymer that undergoes the stabilization. Because the reacts are of a highly exothermic nature, the total amount of heat released is so great that it is difficult to control the temperature. Care should be taken to avoid processing too large a number of fibers in close proximity, which would cause a localized heat buildup, and would prevent the transfer of heat into the atmosphere around the fibers or the fiber assembly (eg, a tow of fiber or a spun or woven fabric). In fact, oxidation stabilization of acrylic fibers has considerable potential for an uncontrolled reaction. In addition, some trace of hydrogen cyanide is evolved during this step, and the content of this component in the furnace atmosphere must be prevented from reaching the exclusive range by injection of nitrogen, as required. In accordance with the above, the above techniques overcome this problem by heating the 5 fibers at a moderate temperature and with a controlled oxygen content for many hours. Control of the atmosphere containing oxygen, for example, air, can be achieved by diluting the air with nitrogen. Since thermal stabilization has tended to be unduly delayed and intense in capital, other different approaches have also been proposed to expedite the desired reaction, for example, through the use of stabilization promoting agents and / or chemical modification of the fiber. acrylic before it can be poured. However, these 5 approaches have also been added to the cost of manufacturing, and have further lengthened the processing time of It has now been found that the degree of oxidation stabilization of a polymer fiber, such as, for example, an acrylic fiber, can be substantially reduced by oxidizing only a portion or external region (when viewed in section). transverse) of the fiber, while the inner portion or core of the fiber remains in a thermoplastic and unstabilized condition, therefore, achieving stabilization of only an outer region of a fiber can be conducted over a period of time much shorter, depending on the desired thickness of the stabilized outer fiber liner Typically, the ratio of the radius of the core to the total radius of the fiber is from 1: 4 to 1: 1.05, preferably from 1: 3 to 1: 1.12 In a ratio of 1: 4, it can be calculated that the percentage by volume that is represented by the nucleus is approximately 6 percent by volume, leaving approximately 94 percent for the External lining In a ratio of 1: 1.05, the percentage by volume quo represented by the core is approximately 91 percent, leaving approximately 9 percent for the outer lining. In general it is preferred to keep the ratio at a value where the volume of the outer lining is relatively small, preferably less than 25 percent, which represents a ratio of 1: 1.12 to less than 1: 1.1", with the purpose to keep the time of the oxidation or carbonization treatment at a minimum without affecting damage I mount the intended commercial operation of the fiber. It will be understood that the proportion can be adjusted to any value, depending on the final use or the physical characteristics desired for the biregionol fiber of the invention. For example, a ratio of 1: 1.12 to 1: 1.16 would be entirely satisfactory to use a multiplicity of bi-regional fibers as thermal insulation for building structures, whereas a ratio of 1: 2 to as high as 1: 3 would be sufficient. for bi-regional ires resistant to ignition, or when used as an electrode for secondary electrical storage devices. The bi-regional precursor fibers are heat treated in an inert atmosphere, and for a period of time sufficient to form an outer region of a thermoset carbonaceous liner which, preferably, is substantially the same thickness as the stabilized outer fiber liner. . However, it will be understood that the processing conditions are difficult to control and maintain to an absolute exact degree, such that there is a precise coincidence of carbonization of the stabilized region by oxidation of only the fiber. Now it has been discovered that this is not critical, and that an exact coincidence of the regions is not absolutely essential. In other words, the oxidation-stabilized region can be carbonized to the extent that the carbonization extends to the thermoplastic core region, without destroying the inner core of the fiber or fiber by itself. It has also been discovered in a surprising manner that the oxidation stabilization of polymer fibers can be controlled, that is, stopped at some point, to produce two regions that are visually and physically distinct from one another, and that these fibers bi-regional precursors are able to survive the subsequent carbonization treatment. It is now taught in the prior art that oxidation stabilization has to be carried out to the extent that all the fiber material is sufficiently oxidized to stabilize the fiber for the subsequent carbonization of the fibers, since the portion of the material A partially oxidized fiber thermoplastic polymer is believed to be highly reactive at temperatures above 200 ° C (see High Performance Fibers II, page L 1). Expectation by the experts in this field, is that the carbonaceous fibers can not be produced without a complete stabilization of the fibers before their treatment at a higher temperature and in a non-oxidizing atmosphere to achieve carbonization. Accordingly, it is surprising that the stabilization, and correspondingly the carbonization of the fibers, does not need to completely include all the fiber material, but that partial treatment can be carried out without impairing the performance of the process itself, or the overall operation of the resulting fibers for their intended purpose. The following Table demonstrates typical physical characteristics for different types of fibers, including the fibers (bi-regional fibers and bi-regional precursor fibers) of the invention: TABLE I From the Table, it can be concluded, for example, that the bi-regional fibers of the invention can be broadly classified into three groups, depending on their particular use and the environment in which they are placed. In a first group (BRF-1), the biregional precursor fiber (BRFP) can be carbonized until the carbonaceous outer skin of the fiber is partially carbonized, and has a carbon content greater than C > R for 'r - cent, but less than 85 percent by weight, is electrically non-conductive, and has no istic character of electrostatic dissipation. A fibrous assembly made from a multiplicity of these fibers is light in weight, non-flammable, and has an excellent possibility of washing, and can be used, for example, in articles of personal clothing, such as jackets, quilts, sleeping bags or the like. The bi-regional fibers can also be made in a wadding or fabric, for example, which can be mixed with other synthetic or natural pounds, including cotton, wool, pol-fot, polyolefin, nylon, rayon, etc. The mixed fibers or thread are non-flammable, and are excellent for use on tolas, carpets, etc. It should be noted that the biregional precursor fiber is useful as a commercial product, and can be used for any of the end-products indicated above. When the precursor fibers biregionals are used as a thermal insulating material, for example, they also perform the function of a fire retardant medium, since the presentation of a fire will convert the external region stabilized by oxidation of the fiber into a carbonaceous region, while it prevents the oxygen from coming into contact with the thermoplastic polymeric inner core region of the fiber, due to thermal protection by the stabilized outer region. The term "electrically non-conductive", as used in the present invention, refers to a fiber having a volume resistivity of 102 to 108 ohm-cm. When the BRF-1 is derived from an acrylic fiber, it has been found that a nitrogen content of the carbonaceous outer shell of 22 weight percent or higher results in an electrically non-conductive fiber. The BRF-1 of this group typically has a density of 1.45 to 1.60 grams / cm3, a Young's modulus of less than 1 MM pei, a possibility of breaking elongation of 4 percent to 12 percent, and an angle of skewing to break from 9 to 13 degrees. The fiber is not measurably sensitive to tearing, and can be easily processed in conventional textile equipment, including intense tear processing operations, such as stretching operations. When these fibers are subjected to a roughness angle of about 9 degrees, the outer liner will tear, but the inner core will remain intact and, consequently, the fiber will not suffer breakage. At a bend angle greater than 9 to 13 degrees, the fibers will actually break. This contrasts markedly with the completely carbonized or graphitic fibers of the present state of the art, which break when subjected to angles of greater than 3 degrees. In a second group (BRF-2), the fiber can be carbonized to a degree where the outer carbonaceous lining of the fiber has some electrical conductivity, ie, the fiber is partially electrically conductive, and has electrostatic dissipation characteristics. The carbonaceous outer skin has a carbon content greater than 68 percent, but less than 85 percent by weight. The low conductivity means that the fiber has a volume resistivity of 103 to 10 ° ohm-cm. Fibers in this group typically have a density of 1.50 to 1.65 grams / cm3, a Young's modulus of 1 to 2 MM psi (6.9 to 13.8 GPa), a possibility of breaking elongation from 3 percent to 9 percent, and an angle of twisting to the breaking of 8 to 10 degrees. This biregional fiber resistant to ignition has a slight sensitivity to tearing, but compares favorably with fibers that are carbonized or graphitized completely, and that are typically very sensitive to tearing, and that break when subjected to higher angles of twisting of 2 degrees.

A fibrous assembly made of a multiplicity of BRF-2 is non-flammable, and is excellent to be used, for example, as an insulation for aerospace vehicles, or as insulation in areas where public safety is a concern. The assembly formed from a BRF-2 multiplicity is lightweight, has low moisture absorbency, good abrasion resistance, together with good appearance and feel. In a third group (BRF-3) the fibers are processed to a degree where the carbonaceous outer skin of the fiber is electrically conductive, and has a carbon content of at least 85 percent, but less than 92 percent in weight, and a nitrogen content greater than 5 weight percent. The BRF-3 is characterized by having a high electrical conductivity, that is, the fibers have a volume resistivity of less than 10 ° ohm-cm. The fibers of this group typically have a density of 1.65 to 1.85 grams / cm3, a Young's modulus of 2 to 18 MM psi (13.8 to 124.? GPa), a possibility of breaking elongation from 3 percent to 7 percent . The fibers have a slight sensitivity to tearing, and can withstand a bend angle at 7 to 9 degrees break without breaking, which is a substantial improvement compared to fully carbonized fibers that are typically extremely sensitive to tearing, and have an angle from breaking to breaking, a, from 1 to 2 degrees. A wadding made from a multiplicity of these fibers, as a result of its higher carbon content, has superior thermal insulation and sound absorption characteristics. This wadding also has a good compressibility and elasticity, while maintaining a better thermal insulation efficiency. The wadding finds a particular utility in the insulation of ovens and areas of high heat and noise. The following Table II shows the typical breaking angles in degrees for different types of fibers, including the fibers of the invention.

TABLE II Reference Source: "H", Physical Properties of Textile Fibers by W.E. Morton and J. .S. Hearle. The Textile Institute, Manchester, England (1975), page 425; "E", experimentally measured following the procedure described by Morton & Hearle on page 421-425 at 65 percent relative humidity, lengths of 1 centimeter, tensile tension of 10 N / m2, and 240 turns per minute.

In a fourth group (BRF-B), the fiber can be carbonized to a degree where the carbonaceous outer shell of the fiber is highly electrically conductive, and has a carbon content greater than 92 percent up to as high as 99 percent. cent in weight. Wide categories of conventional fibers falling in this group are described in "Encyclopedia", supra, page 641, and are generally defined as "high strength" and "high modulus" fibers, where the treatment temperatures are 1000 ° C at 2500 ° C. BRF-B with a carbon content greater than 92 percent in the outer shell is characterized by having a volume resistivity of less than 10 ~ 2 ohm-cm. The fibers of this group typically have a density of about 1.70 to 1.87 grams / cm3, a Young's modulus less than 1 MM psi (<6.9 GPa) at 30 MM psi (207 GPa), but can be as high as 50 MM psi (345 GPa), depending on the degree of carbonization, that is, the carbon content and the thickness of the external graffiti lining region. These fibers have an elongation potential at break of 2 percent to 5 percent, and are somewhat sensitive to tearing, although they still compare very favorably with conventional carbon or graphite fibers that are typically extremely sensitive to tearing. The fibers are particularly suitable for use in electrodes for secondary storage devices, especially batteries. Fibers can withstand a bend angle to break from 4 to 8 degrees without breaking, which is a substantial improvement compared to the fully carbonized and graphitized fibers of the present state of the art, which are extremely sensitive to tearing, and typically have a breaking angle, a, of 1 a? degrees. It will be understood that the Young's modulus for any of the bi-regional fibers resistant to ignition described above, may be a little higher than indicated, since the Young's modulus, to a great degree, depends on the degree of carbonization of the external lining and the depth of carbonization of the fiber by itself, that is, the radical thickness of the outer carbonized region of the fiber. Polymeric materials that can be suitably used herein to make the pounds of the invention, include any of the well-known polymers that are capable of being stabilized and carbonized to form the fibers. Exemplary of these polymeric materials are copolymers and terpolymers of polyol, polyphenyl, and polyvinylidene chloride. Other well-known polymeric materials include polyamides aromatics (Kevlar ™), polybenzimide resin, Saran ™, and the like. A mesophase pitch (petroleum or coal tar) containing particulate impurities or additives may also be suitably used. Preferably, the polymer composition for the manufacture of the fibers of the invention is a polymeric or subacrylic polymer (as hereinafter defined). It is known in the art and it is an accepted standard imposed by the Federal Trade Commission, that the term "acrylic" is applied to any synthetic long chain polymers composed of at least 85 weight percent molar acrylonitrile units, and less than 15 per mole percent of another polymer. Fibers made from these acrylic compositions are normally spun wet, and are limited to fibers having a circular cross section. The acrylic polymers which are the materials of choice in the preparation of the fibers of the invention, are selected from one or more of the siq lenses: homopolymers based on acrylonitrile, copolymers based on , acrylonitrile, and terpolymers based on acrylonitrile. The copolymers typically contain at least about 85 mole percent of acrylonitrile units, and up to 15 mole percent of one or more monovinyl units which are copolymerizable with acrylonitrile, including, for example, esters of methacrylic acid and esters of acrylic acid, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylate of butyl, acrylate of methyl, and ethyl acrylate; vinyl esters, such as y ~ vinyl acetate and vinyl propionate; Acrylic acid Lico, methacrylic acid, maleic acid, itaconic acid and the salts thereof; vinylsulfonic acid and the salts thereof. In accordance with a further embodiment of the invention, it is preferred to make the fibers of the invention from a subarylic polymer as described in pending European Application Serial No. 95202056.8, filed on July 27, 1995, in the name of FP McCullough, which consists of a long-chain polymer selected from the group consisting of copolymers and terpolymers containing less than 85 mole percent of acrylic units, but more than 15 mole percent of the aforementioned monovinyl units, copolymerized therewith. The number of units of monovinyl that may be present in a subarylic polymer, preferably from more than 15 percent - * • up to 25 percent by weight. However, you can mix as much as 35 mole percent of the monovinyl units with the acrylic units, to make the The mixture can be extruded more easily molten through a nozzle or extrusion nozzles, while the polymer mixture is in a heat softened condition. The heat-softened filament, thus extruded, can be stretched and attenuated, while under tension, it forms a finer denier filament (ie, where the fiber length unit is increased with respect to weight), which has a relatively smaller diameter, compared to extruded fibers made of a conventional acrylic resin. The sub-acrylic polymer of the invention can preferably be used in the extrusion of a filament having a non-circular cross-section. A plasticizer can be added to, or mixed with, a higher polymer, to facilitate processing, and to increase the flexibility and hardness of the final product by internal modification (solvation) of the polymer molecule. Suitable plasticizers can be any organic compound, including, for example, vinyl chloride, methyl acrylate, methyl methacrylate, polyvinyl chloride, and cellulose esters, phthalates, adipates, and sebacate esters, polyols, such as glycol ethylene and its derivatives, tricresyl phosphate, castor oil, etc. The physical form of the polymer fiber which can be suitably used in the production of the carbon-containing or oxidation-stabilized bi-regional fibers by oxidation of the invention, can be the usual fiber of generally circular cross-section, having an aspect ratio greater than 100: 1. Preferably, the fibers of the invention have a non-circular cross-sectional shape, as described in Modern Textiles, second edition, 1982, by D.S. Lyle, John Wiley & Sons. In the chapter titled "Fiber Properties", pages 41 to 63, different natural and polymeric fibers are described that have different surface contours, that is, smooth, rough, saw, etc., which is said to have an influence on cohesiveness, elasticity, lifting, and thickness. The polymer fibers having different non-circular cross-sectional shapes are described in Tables 2 to 9 on pages 52 and 53, and include tubular, triangular and regular, fluted, oval, etc. The reference to non-circular cross-section fibers and their use in electrodes is also made in the pending United States Patent Application Serial Number 08 / 372,446, filed January 13, 1995, in the name of Francis P. McCullough. The non-circular cross-section fibers of the invention are preferably multi-lobed, for example, of a trilobal or pentalobular cross section. The fibers of the invention can be made more easily, and at a substantially lower manufacturing cost, from an unfiltered polymer composition, such as, for example, an acrylic or sub-acrylic polymer which can contain from 0.0001 to 5 percent by weight. weight of particulate matter, where the individual particles have a diameter of less than 0.1 microns, preferably less than 0.001 microns. The submicron particles are naturally present in any polymeric composition and, therefore, will also be present in the polymeric compositions that are extruded to form fibers for use in the manufacture of textile articles, for example. These particles are in general organic or inorganic materials that are insoluble in the melt or polymeric addition. The term "unfiltered", used herein, is applied to polymeric compositions which, when in a molten phase and during manufacture, are not subjected to the usual microfiltration process to remove impurities, such as non-polymeric inclusions, from the polymeric compositions. Within the scope of the invention, it is also contemplated to introduce an additional amount of particulate matter into submicrons, such as, for example, vaporized silica, calcium oxide and various other inorganic materials, such as silicates in the polymeric composition. It has been found that adding 0.01 to 2 percent, preferably 0.1 to 1 percent, of these particles in submicrons in the polymer composition will reduce the formation of a high degree of order or crystallinity in the polymer composition of the spun fiber. . When the biregional precursor fiber is subsequently heated and carbonized in a non-oxidizing atmosphere, it lacks the rigidity, brittleness, and high modulus normally associated with traditional carbon or graphite fibers, while still exhibiting low electrical resistivity. and a good uniform and contiguous surface structure, free of voids, pores and pitting normally associated with absorbent carbon materials. These characteristics differentiate the bi-regional fibers of the invention from absorbent carbon materials of high surface area. The fibers of the invention are essentially continuous, that is, they can be made up to any desired length, they can be essentially linear or non-linear (ie, non-linear when they are crimped in a conventional manner into an air-liner crimping mechanism, box, or gear), and possess a high degree of flexibility that manifests itself in a fiber that has a much greater capacity to withstand tear, that is not brittle, and that has a bending tension value from more than 0.01 up to less than 50 percent, preferably from 0.1 to 30 percent. These properties allow the fibers of the invention to be formed in a variety of assemblies or configurations for use in many different types of applications, such as wadding, fabrics, etc. In contrast, the bending tension value of a conventional carbon fiber or graphite, for example, with a high modulus, is substantially less than 0.01 percent, and often less than 0.001 percent. Moreover, the non-circular cross-sectional shape of a multiplicity of non-linear fibers of the invention is particularly convenient, for example, especially in batts, since they are capable of forming a highly interlaced fibrous structure having a thermal R value more high at a given density, compared to a batt containing fibers having a substantially round cross-sectional shape. This is mainly due to the surface interactions between the fibers and some improved Knudsen effects. In the mixed yarns, the non-circular cross-section of the fibers of the invention also exhibits greater flexibility and deflection recovery without breaking, compared to a conventional cross-sectional fiber, mainly due to the smaller apparent diameter of the non-woven form. circular fiber. Although the fibers of the invention may have a diameter as large as 30 microns, it is preferred to form fibers of a relatively small diameter of 2 to 15 microns, preferably 4 to 8 microns, since the diameter of the fiber is generally proportional to its surface area. Specifically, two fibers of a generally round or circular cross section, and having a diameter of 5 microns, will present approximately four times the surface area of a single fiber having a diameter of 10 microns.

Where bi-regional fiber is intended to be used as an electrode for a secondary energy storage device, the outer carbonized fiber liner preferably has a surface area of more than 1 to 150 m2 / gram, preferably more than 5 m2 / gram, and more preferably 10 to 50 m2 / gram, provided that the method employed to increase the surface area retains the structural surface integrity of the fiber. The surface area of the non-circular fiber is substantially higher, compared to the circular fiber taught in the prior art, which generally prefers a surface area that is smaller than that which would be associated with the activated absorbent carbon (it has a surface area). 50 to 200 m2 / gram). It is known that the activated absorbent carbon has a very porous and pitted surface, and one that is not essentially contiguous, that is, without pitting and pores. The reason for the use of bi-regional fibers of the invention having a contiguous surface and, however, one having a relatively high surface area, lies in the fact that the cross section geometry is changed from the typical generally circular cross section of the prior art, up to the non-circular cross-section previously described herein, which increases the surface area of the fiber for a given diameter, while retaining the surface structural integrity characteristics.

With particular reference to Figure 1, an bi-regional ignition resistant fiber of the invention having a generally circular cross-sectional shape is illustrated. The fiber is generally identified by the reference numeral 10, and comprises an inner core region 12 of a thermoplastic polymer, and a surrounding outer region of a thermoplastic stabilized liner or a thermoset carbonaceous liner. The fiber has a nominal cross-sectional diameter, when bisected, which is the linear distance from any point along the outer surface of the fiber through the center of the fiber, and to an opposite point on its outer surface. Accordingly, the nominal diameter of a circular fiber is also its "effective" diameter. The bi-regional precursor fiber of the invention would have essentially the same configuration, except that the outer region of the tibia would be stabilized by oxidation. With reference to Figure 2, a fiber, generally identified by the reference number 20, having a generally trilobal cross-sectional shape, having an enlarged surface area for a given nominal external fiber diameter, compared to the fiber, is illustrated. Figure 1. The fiber has an inner core region 22 of a thermoplastic polymer, and a carbonaceous lining thermofixed or stabilized by external oxidation represented by the shaded reflection 24. In the fiber of trilobal cross section, the external nominal radius the fiber is identified by the arrow Rn pointing to the outermost dotted line 26 that encloses the fiber, and which is generally extended tangentially along the external extension of the lining lobes. The effective radius of the fiber is shown by the arrow Re pointing to the dotted line 28, which intersects the valleys of the trilobal fiber. The nominal radius of the core is identified by the arrow Cn pointing to the dotted line 30, which extends generally tangentially along the outer extension of the lobes of the core 22. Therefore, in the case of a trilobal fiber, the nominal diameter is equivalent to the nominal diameter of a fiber of generally circular cross section, but its effective diameter Re is substantially smaller, as represented by the dashed line circle 28. Not only the smallest effective diameter of the trilobal fiber provides to the fiber greater flexibility, but this flexibility is improved by the fact that the effective radius of the core is smaller than the nominal radius of the core, and in addition, the fact that the core is made of a thermoplastic polymer material having an inherently higher flexibility, comparing with a stabilized fiber that has been carbonized through its entire cross section. The improved flexibility of the biregional fiber resistant to ignition is represented by a substantially reduced sensitivity of the fiber to tearing, although, as indicated above, the sensitivity to tearing of the fiber is influenced to a greater degree by the ratio (r: R), and by its volume density, that is, the sensitivity to tearing increases with an increase in the thickness of the external carbonaceous lining and its degree of carbonization or graphitization. The value of fiber bending tension is generally less than 50 percent, which is highly desirable in the formation of relatively thin bends in the fiber without breaking the fiber. Here again, the bending stress value is further improved by the fact that the fiber is of a non-circular and bi-regional construction. Optionally, the fibers of the invention may also be in the form of a hollow fiber or generally tubular fiber, or may be provided with one or more central passages extending along the length of the core of the fiber. These types of fiber represent a saving in the amount of polymer composition used without sacrificing performance. Additionally, the internal passages make the fiber even more flexible. It will be understood that a fiber of tubular cross-section would have concentric regions of a thermosetted or carbonaceous outer region, and a thermoplastic inner ring core.

The configuration of the trilobal cross-sectional fiber illustrated here is representative of only one type of cross-sectional configuration, and it will be apparent to the skilled person that the fiber can be made in any desired cross-sectional shape during its manufacture, and that this form is limited only by the limitations of making an extrusion die for the extrusion of a polymer composition through the die, the composition of the polymer, the temperature, etc. The number of lobes of a fiber is limited only by the fact that the heat-softened polymer that is extruded from a die, has a tendency to flow, and thus, obliterates the cross-sectional shape to revert to a almost circular cross section shape. For other cross-sectional shapes of the polymer fibers, reference is made to "Modern Textiles" by D.S. Lyle, particularly pages 52 and 53. Preferably, the bi-regional fiber of the invention should have the following physical properties criteria: (1) A ratio (r: R) of the radius of the core region (r) to the radius total fiber (R) from 1: 4 to 1: 1.05, preferably from 1: 3 to 1: 1.12. This proportion is applicable, of course, to the biregional precursor fiber, as well as to the bi-regional fiber. The ratio of the volume of the core to the total volume of the bi-regional fiber has a substantial effect on the operating properties. Therefore, if resistance to ignition is desired, then a ratio (r: R) of 1: 1.05 to 1: 1.2 gives an acceptable performance, while for the fire blocking operation, a ratio of 1: 1.12 is desirable. to 1: 1.4. (2) A density of 1.20 to 1.32 grams / cm3 for the bi-regional precursor fiber, preferably 1.24 to 1.28 grams / cm3. However, it should be understood that the density of the fiber depends on the ratio (r: R) of the radius of the core (r) with respect to the diameter of the fiber (R). For example, if the ratio is 1: 1.05, where the oxidized liner occupies a very small portion of the fiber volume, the density of the fiber approaches that of a polymer fiber, in the case where the polymer fiber derived from an acrylic polymer, the density is typically 1.15 to 1.19 grams / cm3, such that the density of the bi-regional fiber with a ratio of 1: 1.05 is slightly higher. (3) A density of 1.45 grams / cm3 at 1.85 grams / cm3 for bi-regional fiber. Typical densities are 1.45 to 1.60 grams / cm3 for fibers where the carbonaceous outer skin is electrically non-conductive, ie, see BRF-1; from 1.50 to 1.70 grams / cm3, where the carbonaceous lining has electrostatic dissipative characteristics, BRF-2; from 1.65 to 1.85 grams / cm3, where the carbonaceous lining is electrically conductive, BRF-3, and up to approximately 1.87 grams / cm3, where the outer lining of the biregional fiber resistant to ignition is graphitic and highly conductive, ie , BRF-B. Typically, the densities of the bi-regional fiber may be a little higher than indicated above, if, for example, the polymer composition used to make the fibers is not filtered and / or contains a high percentage of a particular material. inorganic aggregate (4) A Young module from month of 1 MM psi (6.9) GPa), but greater than 0.3 MM psi (2.07 GPa), up to 50 MM psi (345 GPa), typically up to 30 MM psi (207 GPa). A module of up to 50 MM psi (345 GPa) can be obtained where the outer carbonaceous fiber liner is predominant, that is, in a ratio of approximately 1: 4 (1 MM psi is equivalent to 1,000,000 psi). (5) An aspect ratio of more than 100: 1 (the aspect ratio is defined herein as the ratio of length to diameter 1 / d of the fiber), and a fiber diameter of 1 to 30 microns (micrometers), preferably from 1 to 15 microns, and more preferably from 4 to 12 microns. (6) A surface area with respect to the bi-regional fiber of more than 1 m2 / gram, and up to 150 μg / gram, preferably more than 5 m2 / gram, and more preferably 10 to 50 m2 / gram. It will be understood that the carbonaceous surface area of the fiber can be as low as 0.1 m2 / gram, but that that low surface area will not provide the optimum in terms of storage capacity or cul de efficiency, where fiber is used as an elede for a secondary storage device. (7) The carbonized outer liner of bi-regional fiber should have a carbon content typically from more than 68 percent to about 99 percent by weight. The carbon content of the outer fiber liner depends somewhat on the type of polymeric precursor composition used. Accordingly, if for example the polymeric precursor composition contains as much as 2 percent of an inert particulate material, the maximum carbon content will be less than 98 percent. (8) Resistivities specific to fibers generally from more than 108 ohm-cm for bi-regional fibers that are elecally non-conductive, to less than 10 ° ohm-cm for BRF-3 that are elecally conductive, and to less than 10 ~ 2 ohm-cm for the BRF-B that are highly conductive, that is, graphite. (9) A fold tension value from more than 0.01 percent to less than 50 percent, preferably from 0.1 to less than 30 percent. (10) A breaking angle of 17 to 23 degrees for bi-regional precursor fibers, and from as low as 4 for BRF-B up to as high as 13 pat to BRF-1. (11) In the case of graphite fibers that are particularly useful for electrodes in secondary energy storage devices, it is preferred that the carbonaceous outer shell of the BRF-B has a contiguous surface which is substantially free of pinholes and pores, , - and that has micropores that represent less than 5 percent of the total surface area of the fiber. With particular reference to Figure 3, a flow diagram illustrating in general a process for converting an acrylonitrile polymer into bi-regional precursor fibers and bi-regional fibers and their different uses is illustrated. final. The process conditions for spinning or coextruding polymer fibers from the compositions described or the present application are generally known in the art. It is preferred that the polymer be selected from a conventional acrylic or sub-acrylic polymer, as described in the present, and that the fibers are of a non-circular cross section. Then the polymer fiber is oxidatively stabilized in a stabilization chamber at a temperature of 150 ° C to 300 ° C in an oxidizing atmosphere. The oxidation time for the fibers of the invention, without However, it is substantially reduced to less than 1 hour, preferably less than 30 minutes. The biregionally produced oxidation stabilized fiber (BRPF) will exhibit distinct visually discernible regions of a translucent or slightly colored inner core of a thermoplastic polymer, and a black outer region of a thermoplastic oxidized liner. An inspection of one end of the fiber (in cross section) under a microscope failed to show a boundary or discontinuity between the inner core and outer shell regions. In effect, the surface of the fiber, seen in cross section, was continuous from an external surface to the center of the core. Then the bi-regional precursor fiber is subjected to a carbonization treatment at a higher temperature and in a non-oxidizing atmosphere, as is generally taught in the art. In the present reference is made to "High Performance Fibers" by Battelle. However, the carbonization time of the biregional precursor fiber is substantially reduced by as much as 30 minutes, as taught in U.S. Patent Number 4,837,076, to less than 3 minutes, preferably from 45 seconds to 3 minutes. minute, depending on different factors, such as the diameter of the fibers, etc., and the desired degree of carbonization. Prior to carbonization, the biregional precursor fiber can be crimped, and then it can be conducted through the carbonization furnace while in a relaxed and unstressed condition, such that the fibers retain their crimped configuration. Here again, an inspection of one end of the bi-regional fiber under a microscope failed to show a boundary or discontinuity between the inner core and outer carbonaceous lining regions. In effect, the surface of the fiber, when dissected and viewed in cross section, was continuous from an external surface to the center of the core. The bi-regional fibers resistant to ignition that have the physical properties of BRF-1 or BRi-2 e as shown in Table I, can be converted into wool in the form of tow or wadding, for example, with R values of insulation high thermal These fibers can be used as insulation for building structures, as fillings for jackets or sleeping bags, and the like. The BRF-2 can also be used as carpet-dissipating electrostatic fibers or for EMI protection of sensitive electical equipment, for example. Fibers having the properties of BRF-3, and having an external electrically conductive region, can be suitably employed in fire retardant (FR) assemblies, and sound dampers, for use in different types of vehicles, such as aircraft, cars or boats. Any of the fibers BRF-1, -2 and -i can be made in different assemblies, such as mixtures, where the fibers are mixed with other natural or polymeric fibers to form ignition resistant and fire retardant assemblies.; compounds wherein the fibers are incorporated into a polymer matrix to make the compounds fire retardants, and to increase the strength of the compound. BRF-3, when formed by compression with a binder, are particularly suitable for use as a fire blocking sheet or panel. Any of these fibers or assemblies may also be provided with different coatings, including an organosilicone polymer that makes the fibers or assembly synergistically substantially more fire retardant, or a hydrophobic coating to cause the assembly to float, and / or - reduce water recollection. BRF-B are particularly suitable for use in electrodes in secondary energy storage devices, such as non-aqueous electrolyte batteries, room temperature batteries, or in an electrode, including bipolar electrodes, for use in lithium ion batteries. The different end-use applications are illustrated more clearly in the flow diagram of Figure 3. Preferred fibrous assemblies consisting of a multiplicity of the fibers of the invention may be in the form of randomly entangled fibers in the form of a wool in the form of tow, a generally flat non-woven sheet, fabric or wadding, a panel formed by compression, a spun or woven fabric, or the like. The example of a preferred fibrous assembly is a generally flat shaped article, such as wadding, made from a multiplicity of individual (ie crimped) non-linear fibers of the invention. In a preferred manufacturing method of a wadding, a heavy skein of 320,000 (320K) polymer fibers is employed. In the case of skeins containing a smaller number of fibers, for example, up to 40,000 fibers, the smallest skeins can be made into a product in the form of woven or spun fabric. It is preferred to form the polymer fibers, preferably in a stabilized condition, in the desired shape (woven, spun, sheet or felt) prior to carbonization. Non-linear biregional fibers in the form of a nonwoven fabric, felt or wadding, and made of continuous or cut biregional precursor fibers, are particularly suitable for use as thermal insulation. These fibers are preferably non-conductive, have a density of 1.45 to 1.60 grams / cm3, have a specific resistivity of 108 to 102 ohm-cm, a Young's modulus of less than 1MM psi (6.9 GPa), and an elongation to breakage from 4 to 12 percent. These fibers are not sensitive to tearing when compared to fully carbonized, electrically non-conductive fibers of comparable density. Preferably, the non-linear biregional fibers have a non-circular cross-sectional shape to provide a wadding with greater flexibility and lift, as well as higher thermal insulation characteristics with higher R-values than the non-circular cross-sectional shape of the fibers, especially in wadding, it produces higher thermal R values at given densities, compared to the wadding containing fibers of round cross section, mainly due to the surface interactions and some Knudsen effects improved in the cracks of the non-circular fibers. Typical for the manufacture of thermal insulation assemblies from non-linear bi-regional fibers are the processes in U.S. Patent No. 4,868,037 and in U.S. Patent No. 4,898,783, issued to F.P. McCullough and collaborators. Insulation assemblies that use bi-regional fibers are elastic, shape reformers, lightweight and non-flammable, have low heat conductivity, high thermal insulation characteristics, are washable, have low moisture retention, high lift and retention of volume, and high cohesiveness. The present invention further contemplates the fabrication of flame retardant and fire blocking assemblies in a manner similar to the general procedures described in U.S. Patent No. 4,879,168, issued November 7, 1989 to F.P. McCullough and collaborators. Different terms, such as "fire resistant" used herein, refer to any of the characteristics of stopping fire, retarding fire, protecting from fire, and barrier to fire. An article is considered fire retardant to the extent that once an ignited flame has ceased contact with the unburned parts of a textile article, the article has the inherent ability to withstand further spread of the flame throughout. of its unburned portion, thus stopping the internal burning process. The recognized tests to determine if a textile article is fire retardant are, among others, the Test Method 34-1966 of the American Association of Texti Le Chemists and Colorists, and the Test of the National Bureau of Standards in DOC FF 3- 71 An article is considered "fire-protective" if it is capable of deflecting flames and radiation therefrom in a manner similar to aluminum-coated protective clothing, which is known in the art. Fire barriers have the ability to be non-flammable, fire retardant, and to provide thermal insulation characteristics.

In accordance with the general teachings of the U.S. Patent No. 4,879,168, at least 7.5 percent by weight of a multiplicity of biregional, non-linear, elastic, configuration-reforming fibers can be blended with natural or synthetic fibers to form a fire-retardant blend. The elastic and reforming characteristics of the biregional fiber configuration depend, to some degree, on the degree of carbonization and the proportion (r: R) • For example, where the proportion indicates that the carbonaceous lining represents a larger portion of the fiber, and that the degree of carbonization indicates that the outer lining is graffitic and has a density greater than 1.85 grams / cm3, and a resistivity in volume less than 10 ~ 2 ohm-cm, the elasticity of the fiber, speaking relatively, is less than that of a fiber wherein the carbonaceous outer shell represents a smaller proportion or ratio (r: R) of the fiber and the carbonization rate is low, that is, where the outer shell is electrically non-conductive. The natural fibers may be selected from, for example, cotton, wool, linen, silk, or mixtures of one or more thereof, with the bi-regional fibers of the invention. The polymer fibers can be selected from, for example, cellulose, polyester, polyolefin, aramid, acrylic, fluoroplast, polyvinyl alcohol and glass, or mixtures of one or more thereof, with bi-regional fibers resistant to ignition of the invention. Preferably, bi-regional fibers are present in the mixture in an amount of 10 percent to 40 percent, are electrically non-conductive, antistatic or conductive, have a specific resistivity of 108 to less than 10 ° ohm-cm, a density from 1.45 to 1.85 grams / cm3, and a possibility of elongation from 3 to 12 percent. These fibers • - biregionals are not sensitive to tearing, or at the most, are slightly sensitive to tearing, compared to fully carbonized fibers that have a similar specific resistivity and are sensitive to tearing. Greater quantities of bi-regional fibers in the mixes improve fire blocking and fire protection characteristics of the mixture. However, it is desirable to maintain a characteristic of the fiber near conventional blends, to have a desirable aesthetic appearance and feel. The present invention also contemplates the The manufacture of fire retardant and fire protective assemblies in a manner similar to the general procedures described in U.S. Patent No. 4,980,233, issued December 5, 1990, and in the U.S. Pat. Number 4,997,716, issued March 5, 1991, both to F.P.

'*' McCullough and collaborators. According to this method, for example, a panel or sheet formed of a polystyrene polymer, or a panel comprising a composite formed by compression of a thermoplastic or thermoplastic polymer, and incorporating from 10 percent to 95 percent, can be provided. percent by weight, based on the total weight of the compound, of a multiplicity of biregional non-linear, elastic, configuration-reforming fibers. The fibers may be concentrated on the surface of the panel in an amount of 10 percent or more, or they may be distributed throughout the polymer matrix in an amount of preferably 20 to 75 percent, optionally, fibers can be applied to the surface, as well as throughout the polymer matrix. Flammability tests for the structure are conducted in accordance with the Ohio State Burn Test, and must meet the standard set forth in FAR 25.853. Conveniently, the conductivity of bi-regional fibers for use in fire retardant and fire protection assemblies can be from electrically non-conductive to conductive, with a specific resistivity of 108 to less than 10 ° ohm-cm, a density of 1.45 to 1.65 grams / cm3, and a possibility of elongation of 3 to 12 percent. These fibers are not sensitive to tearing when they are electrically non-conductive, but they gradually become more sensitive to tearing as the degree of carbonization increases from non-conductive to conductive, however, in view of the fact that the fibers Since biregional fibers always include a core of a thermoplastic polymer 5, the sensitivity to tearing will be substantially less for the fibers compared to the fully carbonized fibers of the prior art In accordance with the foregoing, bi-regional fibers are slightly sensitive to tearing, As a result, they become slightly conductive or conductive, but become more as the fibers become more graphitic.In general, the low sensitivity to desquamation produces less fiber breakage and, consequently, provides a larger fiber population. longer in all textile operations, 5 including the manufacture of non-hilad assemblies os, such as wadding, fabrics or similar. The low sensitivity to desquamation becomes especially critical in yarn spinning from a fiber blend, in the manufacture of carpets, spun fabrics and the like. In the thread spinning operation, 0 there are several stretching operations which are high tear operations. Conventional carbonaceous fibers exhibit significant breakage of the fibers during these manufacturing operations, unless the speed of operation of the manufacturing equipment is substantially reduced.

The present invention also resides in an element for synergistically improving oxidation resistance and thermal stability of biregional fibers in accordance with the general procedures described in the U.S. Patent Number ,024,877, issued on June 18, 1991 to F.P. McCullough and collaborators. According to this method, the bi-regional fibers are mixed with 0.5 to 90 weight percent of an organosilicone polymer derived from the hydrolyzed partial condensation product of a compound selected from the group consisting of RxSi (0R ') 4_? and RxSi (00R ') 4_x, wherein R is an organic radical, and R' is a lower alkyl or phenyl radical, and x is at least 1, and less than 4. Preferably, the organosilicone polymer is selected from of the group that is based on trimethoxy ethylsilane and trimethoxyphenylsilane. The bi-regional pounds, when coated with as little as 0.5 percent of the organosilicone polymer, exhibit a substantially improved fire retardancy. Compounds wherein the organosilicone polymer is present in an amount of as much as 90 percent by weight of the compound, are useful in applications such as packaging, for example. According to one embodiment, the invention relates to a composite comprising a synthetic resin, such as a thermoplastic or thermosetting resin, which are compressed together with a wadding of bi-regional fibers. Prior to compression, the batt is treated with an organosilicone polymer in an amount to provide better resistance to ignition. In general, up to about 20 percent, preferably about 10 percent, by weight of a polymerizable silicone resin is used. This compound will be useful, particularly in the formation of structural panels resistant to fire or fire retardants, for use in vehicles and installations, particularly airplanes. In another embodiment, 10 to 90 percent, preferably 20 to 75, percent by weight of the bi-regional fibers can be used in combination with a synthetic resin in the manufacture of a compound. The synthetic resin used in the compounds can be selected from any of the polymeric materials of conventional type, such as thermoplastic or thermosetting polymers. Compounds with a higher charge of the bi-regional fibers are particularly useful in the formation of fire blocking structural panels, for use in vehicles and installations, particularly ships and airplanes. Many compounds and structures are possible, and when they are prepared for a specific application, they will depend on the mechanical properties desired by the end user. In general, it has been found that biregional fiber charges of 10 to 75 weight percent are preferable for the preparation of flexible panels, in combination with the binder resins and / or the organosilicone polymer or the resin. The present invention also relates to floating fibrous assemblies, as described in the Patent of the United States of America Number 4,897,303, issued on January 30, 1990 to F.P. McCullough and collaborators, using bi-regional fibers. Bi-regional non-circular fibers are particularly preferred which provide a larger surface area and greater flexibility. A multiplicity of these fibers can form a wadding or filling that has a better cohesiveness, and where the fibers form smaller interstitial spaces that provide the wadding with a better flotation. In addition, the floating assembly is lightweight and provides good thermal insulation, has a low water absorption, and is fire retardant. In accordance with the procedure described in U.S. Patent Number 4,897,303, the bi-regional fibers are coated with a water-insoluble hydrophobic composition, which can be any lightweight, curable or curable composition, which can be deposited as by spraying, dipping and the like, to adhere to the fibers. Suitable compositions include high molecular weight waxes, haloaliphatic resins, thermosetting and thermoplastic resins, ionomers, silicone products, polysiloxanes and the like. Preferred coatings include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, etc. The floating assembly employing the bi-regional fibers, is particularly in articles, such as fillers for personal clothing, for example, jackets, sleeping bags, flotation equipment and the like. The electrically conductive bi-regional fibers of the invention are particularly adapted for use in electrodes in secondary energy storage devices, especially batteries. The BRF-B have a density of 1.70 grams / cm3 at -1.87 grams / cm3, a specific resistivity of less than 10 ~ 2 ohm-cm, a Young's modulus of 3 to 30 million psi (20.7 to 207 GPa) ), a possibility of elongation from 2 percent to 5 percent, and a bending tension value from 0.1 to 30 percent. These bi-regional electrically conductive fibers have a greater flexibility, compared with the commercially available electrically conductive carbon or graphite fibers, which are carbonized throughout their cross section in view of the presence of the internal thermoplastic core. The present invention also relates to different types of electrodes, including bipolar electrodes and pseudo-bipolar electrodes employing linear or non-linear BRF-B. Different types of batteries in which BRF-B find utility are described in the Patents of the United States of America Numbers 4,830,938 and 4,865,931 to McCullough and collaborators. The flexible bi-regional graphite fiber electrodes of the invention can also be easily adapted to other battery systems, particularly ion cells of , lithium, as described in the Patent Application of the United States of America pending Serial Number 08 / 372,446, filed January 13, 1995, wherein a bipolar pseudo-electrode has a portion thereof coated with a lithium salt of a metal oxide. In the lithium-ion cell, the metallic lithium electrode is replaced by a Anode, which is based on a carbonaceous material, which forms intercalation compounds with lithium ions. The initial source of the lithium ions is the cathode material, which may be a lithium metal oxide (lithiated metal oxide), such as, for example, LiCo02; LiNi02 and LiMn204. There is never any metallic lithium in the lithium ion cell during normal operation, and according to the above, lithium ion cells are inherently safer than cells containing metallic lithium. During charging and discharging, the lithium ions are oscillating through a Organic non-aqueous electrolyte between the electrodes, as electrical energy is introduced or withdrawn through an external electrical circuit. More specifically, during the charging cycle, the metal oxide releases an electron towards the carbonaceous material electrode, while the lithium ions move from the cathode to the carbonaceous material electrode to form C ~ Li +. High-modulus, chopped pitch fibers are currently used, which are held together with a binder, to achieve the flexibility of the electrode. Although this allows some freedom in the manufacture of the shape of the electrode, it does so at the expense of giving the electrode a high internal resistance, due to the high contact resistance at each contact between each of the chopped carbon fibers. The use of the continuous flexible BRF-B of the invention, provides both the freedom to make the electrode in a variety of configurations of different shape, as well as to lower the internal resistance of the electrode by several orders of magnitude. In a further embodiment, the terminal electrode of a lithium ion cell consisting of a substantially flat, electrically conductive collecting mesh plate or sheet is provided with a metal oxide coating. A conductive mesh can be made of any electrically conductive metal, preferably nickel, but it can also be made of carbon or graphite, which is coated with a conductive metal. The mesh is provided with a coating of a lithium salt of a metal oxide of the empirical formula Li (MO) 2, wherein M is a metal selected from the group consisting of Vllb and VlIIb. The metals are typically selected from the group consisting of Co, Ni and Mn, where n = l for Co and Ni, and n = 2 for Mn. In the usual manner, a terminal electrode, comprising a multiplicity of the BRF-B, is placed in a terminal cell. A partition wall of the internal cell divides the internal chamber of the housing into the pair of terminal cells. A bipolar pseudo-electrode has a middle portion thereof embedded in the partition wall itself, or embedded in a putty resin provided in the partition wall to seal the bipolar pseudo-electrode in the wall, and to prevent wick formation of the electrode from one cell to the adjacent cell. The bipolar pseudo-electrode is bent in such a way that portions of it are placed in each of the terminal cells, to form counter-electrodes with the terminal electrodes. The bipolar pseudo-electrode is formed of a multiplicity of BRF-B. A portion of the electrode fibers is provided by a coating of a lithium salt of a metal oxide of the empirical formula Li (MO) 2, wherein M is a metal selected from the group consisting of Vllb and VlIIb. Preferably, the metals are selected from the group consisting of Co, Ni and Mn, where n = l for Co and Ni, and n = 2 for Mn. Here again, the metal oxide coating preferably is selected from the group consisting of Co02.; Ni02 and Mn204. Each of the terminal electrodes is separated from its counter-electrode by an electrically non-conductive, ion-permeable flat sheet electrode separator, and each terminal electrode is provided with a current collector and a terminal, and the cells they are provided with a non-aqueous organic electrolyte. Other energy storage devices that are contemplated within the scope of the present invention are those of a generally cylindrical shape, and containing at least one pair of flexible carbon electrodes that are wound in a spiral or in a configuration of jelly roll, or that are placed in a concentric relationship inside the cylindrical housing, as illustrated in Figures 4, 5 and 7 of the pending European Patent Application, with serial number 95202056.8, filed on July 27, 1995 by FP McCullough.

Example 1 A skein of 40k (lk = 1000 fibers) of acrylic fibers containing about 94 percent acrylonitrile, 4 percent methacrylate, and about 2 percent itaconic acid is made by the wet spinning method traditional. The acrylic fibers have an average diameter of 11 microns. Then the skein of fiber is stabilized by oxidation in air while it is under tension at a temperature of 224 ° C for 20 minutes. The density of the fiber stabilized by oxidation is 1.25 grams / cm3. The fiber is cut and analyzed under a polarized light microscope and shows a clear differentiation between a thermoplastic outer shell stabilized by black oxidation, and a translucent to slightly colored internal non-oxidized thermoplastic core. The oxidized outer lining of the fiber is not physically separated by a boundary or discontinuity of the non-oxidized core, when seen in cross-section. The ratio of the radius of the core to the radius of the fiber is measured and determined in 1: 1.29. The twisting angle at break was determined at 18.5. Then stabilized precursor fibers are textured into a dynamic air stream, and treated by heat at a temperature of 550 ° C in a tube furnace under an oxygen-free N2 atmosphere purged for 1.5 minutes, while in a relaxed condition. and not stressed. The resulting bi-regional fibers have an aspect ratio greater than 10,000: 1, and a nominal fiber diameter of 9.5 microns. The fibers are resistant to ignition, non-flammable, and flexible, have a fold-strain value of 0.1 percent, a density of 1.54 grams / cm3, a Young's modulus of 1 MM psi, a surface area of 3 m2 / gram, a volume resistivity of 106 ohm-cm, a breaking angle to break of 8.5, and a limited oxygen index greater than 47. The analysis of the section area The cross-section of a single fiber under a polarized light microscope shows a clear visual distinction between a black carbonaceous outer shell and a non-oxidized internal thermoplastic core translucent to slightly colored. The carbonized outer lining of the fiber is continuous and is not physically separated from the thermoplastic core, when viewed in cross section, by a boundary or a discontinuity. The limited oxygen index (LOI) values were determined, and compared with the biregional precursor fiber 5 and the flexible biregional fiber resistant to ignition of the invention. The results are stipulated below: MATERIALS LOI VALUES Polypropylene 17.4 0 Polyethylene 17.4 Polystyrene 18.1 Rayon 18.6 Cotton 20.1 Nylon 20.0 5 Polycarbonate 22 Rigid polyvinyl chloride 40 Bi-regional precursor fiber 40-44 Bi-regional fiber 40-55 Graphite 55 The previous example was repeated using acrylic fibers made by the traditional wet spinning technique, and containing approximately 94 percent acrylonitrile, 4 percent methacrylate, and at least .01 percent impurities in submicrons, ie , particles that are not removed by microfiltration. Similar results are obtained, except that the fibers were slightly less rigid than fibers made containing less than 0.01 percent impurities in submicrons. The fibers are resistant to ignition, non-flammable, and flexible, and have a breaking angle of 8.0 degrees, and a limited oxygen index of 48.

Example 2 Several samples of a skein of 6k fibers, with a diameter of 12 to 13 microns, and of the same composition as in Example 1, were stabilized by oxidation, and then analyzed by density and proportion (r: R) from the core to the fiber. The analytical results of the tests are stipulated in the following Table III: TABLE III From the previous Table, it can be seen that the density and the degree of oxidation of the fiber increase with the residence time. Sample A is not an example of the invention, since the percentage by volume of the core was not enough to effectively distinguish fiber from fully oxidized fibers. In a ratio of 1: 6.25, the core represents only about 2.6 percent by volume of the total volume of the fiber, which is insufficient to impart the desired bi-regional characteristics to the fiber. In a ratio of 1: 4, the percentage by volume for the core increases to approximately 51 percent, with a corresponding decrease in fiber density. From the data in the Table, it can also be deduced that an increase in residence time and in temperature results in an increase in density. Samples B, C and D, on microscopic inspection, clearly show a difference in texture and color between the regions of the core and the regions of the black oxidized outer lining, but do not show a boundary or discontinuity between the regions.

Example 3 A skein of trilobular sub-acrylic fibers comprising 83 percent acrylonitrile, 14 percent vinyl chloride, and 3 percent itaconic acid units is made by the traditional melt spinning technique, and they have a trilobal cross section as shown in Figure 2. The fibers are stretched during extrusion to attenuate the fibers, and then they are oxidatively stabilized according to the procedure stipulated in Example 1. Then the stabilized fibers are carbonized at a temperature of 950 ° C in a tube furnace under an N2-free 02 atmosphere purged for 1.5 minutes. The resulting fibers are non-flammable, have a nominal fiber diameter of 8.0 microns, an effective fiber diameter of 4 microns, and an aspect ratio greater than 10,000: 1, and a limited oxygen index of 47. The ratio of the radius from the core to the radius of the fiber is measured and determined in 1: 1.5. The fibers are flexible and have a tension value * ~ "of 0.2 percent bending, a breaking angle of 7, a surface area of 11 '/pr.imn, a density of 1.7 grams / cm3, a module of Young of 4 MM psi, and a volume resistivity of 0.085 ohm-cm The surface of 5 fibers, when viewed in cross section under a polarized light microscope, does not show a boundary or discontinuity between the regions.

Example 4 A skein of 40k of the biregional oxidation stabilized precursor fibers, BRPF, made according to the procedure of Example 1, is turbid by a standard crimper mechanism, and is passed over a conveyor belt without applying tension or traction on the curly skein. Then the curled skein is passed through a heated oven maintained at a temperature of 950 ° C. The furnace is constantly purged with nitrogen. The residence time in the oven is 1.25 minutes. A skein of these ripple-resistant bi-regional fibers is produced, which have a thermoplastic carbonaceous outer shell and a thermoplastic inner core. The ratio of the radius of the core to the radius of the fiber is measured and determined in 1: 1.4. The density of the fiber is measured at 1.58 grams / cm3, and the fibers have a limited oxygen index greater than 47. The fibers are non-flammable and resistant to ignition, and have a volume resistivity of 106 ohm-cm, an elongation of 8 percent, a pseudo-elongation of 15 percent, a breaking angle at break of 9.5 degrees, and a tenacity of 8g / d. The skein of crimped fiber is cut into different lengths of about 6 to 7.5 centimeters, and fed into a textile upper roll carder. The fibers are separated by the carder treatment in a fluff-like wool, where the fibers exhibit a high degree of inter-securing, as a result of the curled configuration of the fibers, and a volume density of 0.2 lb / ft3. Wool in the form of a fluff is suitable as a thermal insulation material for personal clothing items, such as jackets or the like, and has the same insulating effect as that of Goose or Duck Do n (feathers) at an index of about one third Part of the weight of Down as the insulating padding. The fluff can be densified by needle punching according to a method well known in the art. The lint can also be treated with a thermoplastic binder, such as a polyester or the like, to form a mat or felt with better cohesiveness and / or stiffness, having a good abrasion resistance.

Example 5 The non-flammability of bi-regional fibers of the invention is determined following the test procedure stipulated in Title 14 of the Code of Federal Regulations, Section 25.853 (b) The test is carried out as follows: A minimum is prepared of three (3) 1"x 5 6" x 6"samples (2.54 cm x 15.24 cm x 15.24 cm) derived from a wadding of the biregional fibers of Example 3. The samples are conditioned by keeping them in a maintained conditioner room at a temperature of 70 ° C + 3 ° C, and with 5 percent relative humidity for 24 hours before of the test. Each sample is supported vertically, and exposed to a Bunsen or Turill burner with a tube of nominal internal diameter adjusted to give a flame height of 1.5 inches (3.8 cm). The minimum flame temperature is measured by a thermocouple pyrometer calibrated in the center of the flame, and is 1550 ° F (815.6 ° C). The bottom edge of the sample is 0.75 inches (1.91 cm) above the top edge of the burner. The flame is applied to the line on the bottom edge of the samples for 12 seconds and then removed.

According to the test, the material is self-extinguishing. The average burn length does not exceed 8 inches (20.3 centimeters), the average after the flame does not exceed 15 seconds, and the flame drips do not continue to burn for more than 5 seconds after falling to the ground. burnt test cabinet.

Example 6 A. Wadding is made by mixing an appropriate weight percentage of each of the respective open bi-regional non-conductive or antistatic fibers in a mixer / feeding section of a Rando Webber Model B, 12"sample size (30.5 centimeters), manufactured by Rando Machine Corp. of Macedon, NY The batches produced are typically 1 inch (2.54 centimeters) of thickness, and have volume densities on a scale of 0.4 to 0.6 _. / l / ft3 (6.4 to 9.6 kg / cm3.) The batts are thermally bonded by passing the Rando batting on a conveyor belt through a bonding furnace. heat at a temperature of about 120 ° C to 150 ° C. Part A batting is immediately taken, and formed into panels, compressing the open fibers on a standard flat plate press at a pressure of 10,000 lb / ft2 (700 kg / cm2) to form panels of 1/4"(0.635 centimeters) in thickness Flammability tests are carried out in accordance with the procedure of 20 the Burned Test of the State of Ohio, which is stipulated in FAR 25.853 The results are shown in the following Table I V with respect to the batts formed by the procedure of Part A: TABLE IV PEB KODELMR 410 8 denier polyester binder fiber. BRF Bi-regional fiber of Example 1 PE Polyester DACRONMR 164 of DuPont 6 denier and cut of 2"Cotton Cotton cutout of 1" untreated OPF Oxidized polyacrylonitrile fiber with a density of > 1.40 grams / cm3 NOMEX * "* M-aramid fiber from DuPont Example 7 Following the procedure of Example 6, similar tests were performed on the panels from 1/8" to 3/16" (0.32 centimeters to 0.48 centimeters) thick, prepared according to the results shown in the following Table V. TABLE V Example 8 According to the procedure described in Patent of the United States of America Number 5,024,877, issued on June 18, 1991, to F.P. McCullough et al. Conducted the following experiment: A. To produce a flexible panel, a wadding of the type described in Table III, Sample 3, is sprayed with a Dow Corning 1-2577 conformal coating (a hydrolyzed partial condensation of trimethoxymethylsilane). ), until 10 percent by weight of the coated batt comprises the coating. The coated batt is compressed on a platen between two vinyl sheets at 25 lb / in2 (1.75 kg / cm2) at a temperature of 260 ° F (127 ° C). Instead of the forming coating, a silicone resin can be used, which is polymerizable, either by heat condensation or free radical condensation. 10 Example 8A - Ignition Resistance Test The resistance to ignition of the panels, using the bi-regional fibers of the invention, is determined following the test procedure stipulated in Title 14 of the Code of Federal Regulations, Section 25.853 (b). The test is done as follows: f r. A minimum of three batches are prepared; each one has a dimension of 2.5 cm x 15 cm x 30 cm, and comprised of 80 percent of bi-regional fibers and 20 percent of20 polyester. The wipes are sprayed with a Dow Corning 1-2577 conformal coating solution (a hydrolyzed partial condensation of trimethoxymethylsilane), which is cured by its contact with the humidity of the air. The sprayed batches are compressed at 25 lb / in2 (1.75 kg / cm2) to a temperature of 260 ° F (127 ° C) to produce flexible panels.

The coating is comprised of 10 percent by weight of the panels. Standard vertical burn tests are conducted in accordance with FAR 25.853b. The panels are conditioned by keeping the samples in a conditioning room maintained at a temperature of 21 ° C + 5 ° C, and at 50 percent + 5 percent relative humidity for 24 hours before the test. Each sample is supported vertically, and exposed to a Bunsen or Turill burner with a tube of nominal internal diameter adjusted to give a flame of 3.8 centimeters in height. The minimum temperature of the flame, measured by a pyro of thermocouple calibrated in the center of the flame, is. of 843 ° C. The lower edge of the sample is 1 to 9 centimeters above the upper edge of the burner. The flame is applied to the centerline of the lower edge of the samples for 12 seconds and then removed. It is said that the material passes the test, yes. the material is self-extinguishing, the average burn length does not exceed 20 centimeters, the average after the flame does not exceed 15 seconds, and there are no flame drips. The material passed the test.

Example 9 In accordance with the process described in United States Patent Number 5,024,877, issued June 18, 1991 to F.P. McCullough et al., The following experiment is conducted: A multiplicity of bi-regional fibers of the invention, as described in Example 3, in the form of a fluff in the form of wool, is spread and sprayed with an aerosol spray containing a fluoroalkane resin in a solvent comprising 1, 1, 1-trichloroethane sold under the registered trademark "SCOTCHGARD" by Household Products Division of 3M. About 90 percent of the outer surface of the batting is coated. Then the fluff is air dried to cure the coating, and weighed. The eraser, when placed in water for two hours, floated. After two hours, the fluff is shaken, squeezed and weighed. Only about o is detected. l percent water absorbency. The coated liner is suitable for use as a flotation aid, and as insulation for shirts, jump suits, and the like.

Example 10 A) In accordance with the general procedure described in Example 1 of the pending United States Patent Application Serial Number 08 / 372,446, a skein of trilobular acrylic fibers containing approximately 86 percent of acrylonitrile, 13 percent methacrylate, and at least .01 by > The percentage of impurities in submicrons, which are not removed by microfiltration, is extruded by the traditional melting technique, using a die former with trilobular extrusion holes. The j of 5 acrylic fibers is stretched during extrusion of the fibers to attenuate the fibers, and then oxidized in air for 25 minutes in an oven, where the temperature gradually increases from 250 ° C to 300 ° C. The fibers ptecm oras ,. 'resulting are bi-regional, and have an internal core of l? a thermoplastic polymer, and an outer shell of an oxidized thermoplastic polymer. The oxidized outer lining of the fiber is not physically separated from the thermoplastic core, to the vet e in cross section, by a boundary or discontinuity. The material of the core and the lining of the stabilized fiber biregional, when seen in cross section, is continuous. The biregional precursor fiber is tested by the twist angle at break in 20.5. The fiber has a limited oxygen index of 40. These fibers are useful in morolas with other natural or synthetic fibers for jackets, bags to sleep, and the like. B) Stabilized precursor fibers of A) are placed in a tube furnace, and are treated at a temperature of 1000 ° C under an atmosphere of 02-free N2 purged for 2.0 minutes. The resulting fibers have a diameter of nominal fiber of 6.8 microns, an effective fiber diameter of 4.2 microns, and an aspect ratio greater than 10,000: 1. The resulting fibers have an inner core of a thermoplastic polymer and an outer carbonized liner. The carbonized outer lining of the fiber is not physically separated from the thermoplastic core, when viewed in cross section, by a Limit or discontinuity. The fibers are flexible and have a bending stress value of 0.1 percent, a breaking angle of 7.5 degrees, a Young's modulus of 5 MM psi, a surface area of 14 m2 / gram, and a volume resistivity. of 0.035 ohm-cm. The ratio of the radius of the core to the radius of the fiber is measured and determined at 1: 1.9. The fibers are tested for their resistance to ignition, and have a limited oxygen index value of 46. These fibers are useful as an electrode material for secondary batteries, and as the conductive component for flexible, thin measuring electrodes of very weight! iqoro for a portable EKG monitor. C) Bi-regional carbonized fibers of B) are placed in a high temperature tube furnace, and treated at a temperature of 1750 ° C under an atmosphere of free 02 N2 purged for 1.2 minutes. The resulting bi-regional graffiti fibers have a nominal fiber diameter of 6.4 microns, an effective fiber diameter of 4.0 microns, and an aspect ratio greater than 10,000: 1. The fibers are flexible, have a bending stress value of 0.1 percent, a breaking angle at break of 5. b, a Young's modulus of 18 MM psi, a surface area of 1? m2 / gram, and a volume resistivity of 0.0035 ohm-cm. The ratio of the radius of the core to the radius of the fiber is measured and determined in 1: 2. These fibers are useful as an electrode material for secondary batteries, and as the conductive component for thin, flexible, lightweight measuring electrodes for an EKG portal iL monitor.

EXAMPLE 11 A skein of trilobal acrylic fibers containing approximately 86 percent acrylonitrile, 13 percent methacrylate, and at least 0.01 percent submicron impurities, which are not removed by microfiltration, is made by techniques of traditional fusion spinning, using a die former with trilobular shape extrusion holes. The skein of acrylic fibers is stretched during the extrusion of the pounds to attenuate the fibers, and then oxidized in air for 1.5 hours in an oven where it gradually increases the temperature from 250 ° C to 300 ° C, followed by carbonization to 1200 ° C in a tube furnace under an N2-free atmosphere purged 02 for 10 minutes. An analysis of the trilobal fibers under a polarized light microscope rauesti to two regions in each fiber that are clearly visually distinguishable from each other by a thermoset black carbonaceous outer shell region and a translucent or colorless internal non-oxidized thermoplastic core region. The carbonized outer lining of the fiber does not physically separate the thermoplastic core, when viewed in cross section, by a boundary or discontinuity, and is continuous. The resultant biregional fibers resistant to ignition, are resultant to ignition and have a limited oxygen index value of 45. The biregion fibers are flexible and have a bending tension value of 0.1 percent, an angle of twist to breaking of 7 degrees, a Young's modulus of 11 MM psi, a nominal diameter of 6.8 microns, an effective fiber diameter of 4.2 microns, a surface area of 18 m2 / gram, and a specific resistivity of 0.035 ohm-cm , and an aspect ratio greater than 10,000: 1. These fibers are useful as a battery electrode material for secondary batteries, and as the conductive component for thin flexible measuring electrodes of very light weight for a portable EKG monitor.

Example 12 A skein of pentalobular eubactric fibers comprising 80 percent acrylonitrile, and 17 percent vinyl chloride, and 3 percent itaconic acid units, is made by traditional melt spinning techniques, and has a pentalobular cross section as shown in Figure? A. The skein of acrylic fibers is stretched during the extrusion of the fibers to attenuate the fibers, and then oxidized in air for 1.5 hours at a temperature of 250 ° C to 300 ° C, followed by carbonization at a temperature of 1100 ° C in a tube furnace under an atmosphere of N2 free of 0 purged for 5 minutes. An analysis of the fibers under a polarized light microscope shows two sections in each fiber that are clearly visually distinguishable from one another such as the black thermo-hardened outer arbaryl region, and a thermoplastic core region. non-oxidised internal translucent or colorless. The carbonized outer lining of the fiber is not physically separated from the thermoplastic core, the verse in cross section, by a boundary or discontinuity. The material of the core and the lining of the biregional fiber, when seen in cross section is continuous. Another analysis of the fibers shows that they are flexible, they have a val Lbr of bending tension of 0.? percent, a twisting angle at the breaking of the joints, a Young's modulus of 4? _M psi, a nominal fiber diameter of 8.0 microns, an effective fiber diameter of 4 microns, a surface area of 22 m / gram, a specific resistivity of 0.045 ohm-cm, and a aspect ratio greater than 1000: 1. These flexible bi-regional fibers are useful as a battery electro material for secondary batteries, and as the conductive component for thin flexible measuring electrodes of very light weight for a portable EKG monitor.

Example 13 Two secondary batteries are constructed, each containing two terminal cells, using electrodes made from the bi-regional fibers resistant to ignition produced in Examples 11 and 12, respectively. The batteries are of a construction similar to the rectangular battery shown in Figure 1 of pending European Patent Application Number 95202056.8, filed on July 27, 1995 (Publication Number 0698935). The electrodes of each cell consist of thin flat sheets made from skeins of biregional fibers resistant to ignition, and have a dimension of 4 square inches (25 cm2). A thin copper busbar, which forms an electron collecting strip, is applied to the ends of the fibers, along one edge of the electrode, immersing the ends of the fiber in a solution of copper sulphate, electroplating from this Slowly move the copper from the copper sulfate solution over the ends of the fiber, until a solid collecting strip has grown along the edge of the flat electrode sheet. A terminal connector is attached by welding to one end of the collecting strip. The collecting strip is covered with a non-conductive Derakane ™ resin coating. A non-spun polypropylene screen having a thickness of 180 to 200 microns is placed between the electrode sheets to be used as a separator sheet. An electrolyte comprising 20 percent LiPF6 in propylene carbonate is dried to less than 5 ppm H20, using highly activated zeolite molecular sieves. The electrodes and separator are dried and assembled in a dry box containing air with less than 1 ppm of water. This assembly is placed in a PVC housing that has a wall thickness of 2 millimeters. The PVC housing is provided on the outer surface, with an aluminum foil having a thickness of 50 microns. The housing is filled with the dry electrolyte and 1.5 grams of highly activated zeolite molecular sieves. Then the housing is sealed with the collector strips and the terminals of each electrode caulked in a Derakane ™ brand vinyl ester resin seal, and over-exiting through the top of the housing cover. Then the finished assembly is removed from the dry box, and tested as a battery cell. The cell is electrically charged at a potential of 5.25 to 5.5 V, and is discharged up to 90 percent of its load capacity. Each cell typically has a coulotic efficiency greater than 99 percent.

The cell is able to have more than 800 cycles without losing capacity or efficiency.

Example 14 Two bipolar cell batteries are constructed as described and illustrated in U.S. Patent Number 4,830,938, using the two types of bi-regional fibers prepared in Examples 11 and 12. The electrolyte and the housing material which has two compartments, are the same as those used in Example 13. The total thickness through each bipolar battery is approximately 1 centimeter. The bipolar electrode, which is twice the size of the respective terminal electrodes, is passed through the wall of the cell connecting the two cells, and is masked in a Derakane ™ resin. This cell is repeatedly loaded and discharged. The charge was made at a potential of 15 volts. The open circuit voltage over the full load is more than 9 volts. The coulombic efficiency is typically more than 99 percent.

Example 15 A secondary lithium ion battery is constructed, which contains two terminal cells with a pseudo-bipolar connecting electrode, using the birefrional fibers produced in Example 12. The battery ee of a battery-like construction shown in the Figure 5 of the United States of America Patent Application Serial Number 08 / 372,446, filed on January 13, 1995 on behalf of FP 5 McCullough. The electrodes of each cell consist of thin flat sheets made of skeins of fibers, and which have a dimension of 4 square inches (25 cm2). A thin nickel bus, forming an electron collecting strip, is applied to the ends of the fiber, as along one edge of the terminal electrode, immersing the ends of the fiber in a solution containing nickel salt, thereby electroplating the nickel slowly from the solution on the ends of the fiber, until a solid collecting strip has grown to along the shore of the flat electrode sheet. A terminal connector is attached, welding to one end of the collecting strip. The collecting strip _,. it is caked on the upper part of the cell wall, which is comprised of a non-conductive DerakanoMR resin coating. A very thin coating is also veneered nickel on a middle portion of the pseudo-bipol r electrode, to which a coating of an active material of LiCo02 is applied. A non-spun polypropylene screen having a thickness of 180 to 200 microns is placed between the electrode sheets to be used as a separator sheet. A The electrolyte comprising 10 percent LiPF6 in propylene carbonate is dried to less than 5 ppm H20, using highly activated zeolite molecular sieves. The electrodes and separator are dried and assembled in a dry box containing less than 1 ppm of water with an air atmosphere. This assembly is placed in a PVC housing that has a wall thickness of 2 millimeters. The PVC housing is provided on the external surface, with an aluminum foil having a thickness of 50 microns. The housing is filled with the dry electrolyte and 1.5 grams of highly activated zeolite molecular sieves. The housing is then sealed with the collector strips and the terminals of each electrode caulked in a Derakane ™ MR vinyl ester resin, and protruding through the top of the housing cover. The finished assembly is then removed from the dry box, and tested as a battery cell. The cell is electrically charged, then discharged at 80 percent of its load capacity. The working voltage of the cell is 3.8 volts. Each cell has a coulombic efficiency of more than 98 percent.

EXAMPLE 16 A core-liner precursor fiber is made from two polymer compositions by coextrusion spinning to form a fiber having an acrylic liner and a modacrylic core. Then this fiber stabilizes for 12 minutes, and carbonized for 1 minute following the procedure of Example 1 to form bi-regional fibers (core-lining). The ratio of the radius of the core to the total radius of the fiber is 1: 1.2. The resulting bi-regional fiber is resistant to ignition, and has a limited oxygen index of 48, and a twist angle at 10 degrees break.

Claims

CLAIMS 1. A bi-regional fiber comprising an inner core region of a thermoplastic polymer composition, and a surrounding outer skin region of a thermoset carbonaceous material, wherein the fiber is resistant to ignition, and has a limited oxygen index value greater than 40. The fiber of claim 1, wherein the ratio (r: R) of the radius of the inner core region (r) to the total radius of the fiber (R), is 1: 4 to 1 : 1.105 3. The fiber of claim 1, wherein the carbonized outer liner region has a carbon content of greater than 68 weight percent, a density of 1.45 to 1.67 grams / cm3, and a volume resistivity of 108 Liasta less than 10 ~ 2 ohm-cm. The fiber of claim 1, wherein the fiber is flexible, has a bending stress value from more than 0.01 to less than 50 percent, and a Young's modulus from more than 0.3 MM psi (2.0 GPa) to 50 MM psi (345 GPa). 5. The fiber of claim 1, having a breaking angle of 4 to 13 degrees. ~ 6. The fiber of claim 1, wherein the fiber is crimped and has a possibility of elongation at break of 2 to 12 percent, and a reversible deviation ratio of more than 1: 1. 7. The fiber of claim 3, having a surface area of more than 1 to 150 m2 / gram, and a contiguous fiber surface that is substantially free of pinholes and pores, this surface having micropores that - represent less than 5%. percent of the total surface area 0 of the fiber. 8. The fiber of claim 1, having a generally circular, non-circular, or tubular cross-sectional shape, and a diameter of 1 to 30 microns. The fiber of claim 1, wherein the polymeric precursor composition comprises a homogeneous acrylic composition, and wherein the inner core region of the fiber and the outer sheath region are continuous, and do not have a boundary or intermediate discontinuity between the regions. 10. The fiber of claim 1, wherein the inner core region of the fiber is composed of a first polymer composition, and the outer shell region is derived from a second polymer composition. The fiber of claim 1, having a coating of an organosilicone polymer derived from the hydrolyzed partial condensation product of a compound selected from the group consisting of RxSi (0R ') 4_x and RxSi (00R' ) 4_x, wherein R is an organic radical, and R1 is a lower alkyl or phenyl radical, and 5 x is at least 1 and less than 4. The fiber of claim 1, which has a coating of a composition water-insoluble polymer, comprising a curable or curable composition selected 'from high molecular weight waxes, haloaliphatic resins, thermosetting and thermoplastic resins, ionomers, silicone products and polysiloxanes. 13. A process for making a flexible bi-regional fiber resistant to ignition, which comprises the steps of extruding at least one homogeneous polymer composition 15 heat-softened thermoplastic through an extrusion die, while the extruded polymer material is stretched to form a fiber, stabilized the drawn fiber in an oxidizing atmosphere and for a sufficient period of time to oxidatively stabilize an outer region 20 of the fiber, thereby forming a stabilized biregional precursor fiber having an internal reqión of a thermoplastic polymer core, and a surrounding outer region of the thermoplastic lining stabilized by oxidation, and then heating the biregional precursor fiber in 25 a non-oxidizing atmosphere at an elevated temperature and for a time sufficient to carbonize the stabilized outer lining region of the fiber, to form an inner region of a thermoplastic polymer core, and an outer region of a thermoset carbonized liner. 14. The process of claim 13, which includes the step of extruding a single homogeneous polymorphic composition comprising an acrylic polymer composition, through the extrusion die, and wherein the time sufficient to oxidatively stabilize the external fiber reqion. , is greater than 5 minutes, but less than 100 minutes, and enough time to carbonize the outer lining more than 5 seconds, but less than 300 seconds. 15. A fiber assembly comprising a multiplicity of bi-regional fibers of claim 1, in the form of a skein of fiber, a non-spun fabric, a wadding, a sheet or board, a spun yarn, or a spun or woven fabric. woven. 16. A fiber assembly comprising a multiplicity of the bi-regional fibers of claim 1, mixed with other natural or polymeric fibers, wherein the bi-regional fibers are present in the mixture in an amount of 10 to 90 percent. 17. An ignition resistant or flame retardant composite, which comprises a multiplicity of the bi-regional fibers of claim 1, mixed with a thermoplastic or thermoset polymer, wherein the bi-regional fibers are present in the compound in an amount of 10 to 90 percent by weight, based on the total weight of the compound. 18. A biregional precursor fiber comprising an inner region of a thermoplastic polymer core, and a surrounding outer region of a thermoplastic polymeric sheath stabilized by oxidation, and wherein the precursor fiber has a breaking angle greater than 17 degrees or more . 19. The fiber of claim 18, wherein the precursor fiber is derived from an active polymer. homogeneous selected from the group consisting of homopolymers, copolymers and terpolymers of acrylonitrile, wherein the copolymers and the terpolymers contain at least 85 mole percent of acrylic units, and up to 15 mole percent of one or more vinyl monomers copolymerized therewith. The fiber of claim 18, wherein the vinyl monomers copolymerizable with acrylonitrile include esters of methacrylic acid and esters of acrylic acid, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate and ethyl acrylate; vinyl esters, such as vinyl acetate and vinyl propionate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, and lae saltse thereof; vinylsulfonic acid and the salts thereof. The fiber of claim 18, wherein the inner core region of the fiber is composed of a first polymeric composition, and the outer shell region is derived from a second polymeric composition. 22. The fiber of claim 18, having a density of 1.20 to 1.32 grams / cubic centimeter. The fiber of claim 18, wherein the precursor fiber is derived from an acrylic polymer selected from the group consisting of homopolymers, copolymers and terpolymers of acrylonitrile, wherein these copolymers and terpolymers contain less than 85 percent molar of acrylic units, and more than 15 mole percent of one or more plasticizer polymers copolymerized therewith. 24. The fiber of claim 23, wherein the copolymers and the terpolymers contain up to 35 mole percent of one or more plasticizer polymers. The fiber of claim 23, wherein the plasticizer polymer is selected from the group consisting of vinyl chloride, methyl acrylate, methyl methacrylate, polyvinyl chloride, cellulose esters, phthalates, adipates, and esters of sebacate, polyols, such as ethylene glycol and its derivatives, tricresyl phosphate, - castor oil, and mixtures thereof 26. The fiber of claim 18, wherein the polymer fiber is derived from a polymer unfiltered acrylic containing from 0.0001 to 5 percent by weight of 5 particulate matter that has a diameter of less than 0.1 microns. The fiber of claim 18, wherein the ratio (r: R) of the radius of the inner core region (r) to the total radius of the fiber (R) is from 1: 4 to 0 1: 1.105 . 28. A fire-resistant and fire-resistant barrier assembly, which comprises at least one structural panel of a compound formed by compression, composed of a thermoplastic or thermoplastic resin matrix containing 10 15 to 95 weight percent of a multiplicity of the bi-regional fibers of claim 1, this r-structural panel being in intimate association with an organosilicone polymer derived from the hydrolyzed partial condensation product of a compound selected from group consisting of R? Si (0R ') 4_? and R? Si (OOR ') 4_ ?, wherein R is an organic radical, and R' is a lower alkyl or phenyl radical, and x is at least 1 and less than 4, wherein the organosilicone polymer is present in a sufficient amount to provide resistance to ignition to the assembly. 29. The assembly of claim 28, wherein the bi-regional fibers have a limited oxygen index value of greater than 40, and have a breaking angle of 4 to 13 degrees. 30. A floating, open cell fibrous assembly, which comprises a multiplicity of bi-regional fibers of claim 1, wherein the bi-regional fibers resistant to ignition are non-linear, and are in the form of a wool in the form of Erase, wadding, felt or fabric, this fibrous assembly having a coating of a hydrophobic polymeric material insoluble in water, cured or set. The assembly of claim 30, wherein the coating comprises a polymer selected from the group consisting of an ionomer, thermoset resin, thermoplastic resin, haloaliphatic resin, silicone elastomer, silicone rubber, polysiloxane and high-weight wax molecular. 32. The assembly of claim 30, which comprises an article of clothing for insulating a part against weathering, and for providing flotation. 33. An electrode for a secondary energy storage device, which comprises a multiplicity of bi-regional fibers, each biregional fiber resistant to ignition comprising an inner core region of a thermoplastic polymer composition, and an electrically conductive outer lining region surrounding a thermoset carbonaceous material, the outer carbonaceous region having a carbon content greater than 5 85 weight percent, and a breaking angle greater than 3 degrees. The electrode of claim 33, wherein the bi-regional fibers are derived from a homogeneous acrylic composition, and wherein the core region ± 0 internal fiber and outer lining region are continuous, and do not have a limit or intermediate discontinuity between regions. 35. The electrode of claim 33, wherein the outer carbonaceous region of the bi-regional fiber has a 15 carbon content greater than 92 weight percent, a volume resistivity of less than about 10 ~ ° ohm-cm, and and a breaking angle at 4 to 10 degrees. 36. A secondary energy storage device comprising a waterproof housing 20 having an internal chamber forming a cell, a pair of electrodes placed in the chamber and electrically isolated from each other, each electrode having a current collector electrically connected to the outside of the housing, wherein at least the positive electrode is comprised of the The electrode of claim 33, and an electrolyte in the cell comprising a non-aqueous, non-conductive, chemically stable solvent, and an ionizable salt dissolved therein, wherein the solvent is selected from compounds having oxygen atoms., sulfur and / or nitrogen bonded to the carbon atoms in an electrochemically non-reactive state, and wherein the salt is an alkali metal. 37. The storage device of claim 36, wherein the electrolyte solvent is propylene carbonate, and the alkali metal salt is a lithium salt. 38. A secondary energy storage device comprising an aqua impermeable housing, this housing forming a chamber - whose inner surface is electrically non-conductive, at least one electrically insulating separating wall for separating the chamber into at least one pair of cells terminals, each terminal cell containing a terminal electrode that is provided with a current collector, and each terminal electrode connecting electrically with a terminal on the outside of the housing to facilitate the flow of stored electrical energy out of, and the energy load. inwardly of the storage device, a bipolar electrode extending from an end cell through the electrically insulating spacer wall and haeta into the adjacent terminal cell, and forming a counter-electrode portion with each terminal electrode, a Ionically conductive separating plate coloc between each of the terminal electrodes and a bipolar counter-electrode portion for electrically isolating the terminal electrodes and the counter-electrode portions from each other, the bipolar electrode and at least one of the electrodes terminating the electrode of the claim comprising 33, and an electrolyte in each cell comprising an ionizable salt in a non-aqueous liquid or in a paste. 39. A high performance secondary energy storage device, which comprises a housing impervious to gas and water vapor, this housing forming a chamber, whose internal surface is electrically non-conductive, at least one electrically insulating separating wall for separating the chamber into at least one pair of cells, the terminal cell containing a terminal electrode which is provided with a current collector, and each of the terminal electrodes being electrically connected to the outside of the housing to facilitate the flow of stored energy towards outside, and the energy charge inward of the storage device, a pseudo-bipolar electrode comprising the electrode of claim 33, extending from a terminal cell to the adjacent terminal cell, and forming counter portions. electrode with each of the terminal electrodes, where the terminal electrode and the counter electrode or from each cell are electrically insulated, and are isolated from one another, wherein a terminal electrode has a collector frame formed of an electrically conductive material, the collector frame being coated with a lithium salt of a metal oxide in the empirical form Li (M02) n, wherein M is a metal selected from the group Vllb and VlIIb of the periodic table, forming a portion of the pseudo-bipolar electrode, the counter-electrode, the coated terminal electrode comprising the flexible bi-regional carbon fibers , and forming the other portion of the counter-electrode, a carbon fiber terminal electrode comprising the biregional carbon fibers coated with a metal oxide (M02) n, wherein M is a metal selected from the group Vllb and VlIIb of the periodic table, and an electrolyte in each cell comprising an ionizable salt in the non-aqueous organic liquid. 40. The energy storage device of claim 39, wherein the metal oxide coating is selected from the group consisting of Co02, Ni02 and Mn204. 41. A composite pseudo-bipolar electrode comprising the electrode of claim 33, having a portion of the bi-regional fibers coated with an ionically active lithium salt of a metal oxide of the empirical form Li (M02), where M is a metal selected from the group Vllb and VlIIb of the periodic table. The electrode of claim 41, wherein the metal oxide coating is selected from the group consisting of Co? 2, Ni? 2 and Mn204. SUMMARY A biregional, flexible, ignition-resistant fiber is described, wherein the fiber is preferably derived from a single homogeneous polymeric precursor composition, the biregional fiber comprising an inner core region of a thermoplastic polymer composition, and a region of outer lining surrounding a material ± 0 carbonaceous thermosetting. The biregional fiber is particularly characterized as having a ratio of the radius of the core region to the total radius of the fiber (r: R) from about 1: 4 to about 1: 1.1.05, a limited oxygen index value greater than 40, an angle of 15 breaking at 4 to 13 degrees, and a bending tension value from more than 0.01 to less than 50 per / hundred. In a further embodiment of the invention, a biregional precursor fiber is described, wherein the biregional precursor fiber is preferably derived from 20 a single homogeneous polymer composition, and wherein the precursor fiber comprises an inner core region of a thermoplastic polymer composition, and a surrounding outer sheath region of a thermoplastic polymer composition stabilized by oxidation. The precursor fiber 25 is particularly characterized by having a breaking angle of 17 to 23 degrees. The invention also resides in a method for making bi-regional fiber resistant to ignition. Preferred end uses are described for biregional fibers resistant to ignition, including thermal insulation; fire-resistant insulation and fire blocking; mixtures of bi-regional fibers with other natural or polymer fibers; coated fibers, composed of a polymeric matrix reinforced with the bi-regional fibers of the invention, fibers l? conductive electrons for battery electrodes, and the like. * * * * * fifteen / twenty 25