Patent application title: METAL/POLYMER COMPOSITE FIBERS
Markus Beissinger (Randolph, NJ, US)
Gregory Cordina (Elmhurst, IL, US)
Steven Dong (Grand Forks, ND, US)
Corey Lerch (Raleigh, NC, US)
IPC8 Class: AD02G300FI
Class name: Fabric (woven, knitted, or nonwoven textile or cloth, etc.) scrim (e.g., open net or mesh, gauze, loose or open weave or knit, etc.)
Publication date: 2012-11-15
Patent application number: 20120289107
A specially engineered composite fiber is provided that is a combination
of weight imparting particles and polymeric compounds, with a specific
gravity totaling about 2 or greater. The composite fiber can be extruded
and melt-spun like a normal polymeric fiber, thus creating a relatively
heavy, weighted material fiber, sheet or fabric.
1. A composite fiber containing a particle component and a polymer
component, wherein discrete particles in the particle component impart to
the composite fiber a specific gravity of at least 2.0.
2. The composite fiber according to claim 1, wherein the composite fiber consists essentially of the particle component and the polymer component.
3. The composite fiber according to claim 2, further comprising a material in a concentration not adversely affecting desirable properties of the composition fiber and chosen from the group consisting of antioxidant, stabilizer, surfactant, wax, flow promoter, solid solvent, and particulate.
4. The composite fiber according to claim 1, wherein the particle component comprises elongated micro-threads imparting weight within the composite fiber.
5. The composite fiber according to claim 1, wherein the particles comprise at least one material from the group consisting of iron, bronze, brass, steel, titanium, an alloy thereof, tin, copper, tungsten, platinum, silver, bismuth trioxide, ferrous oxide, silver oxide, organic compounds, pure polymeric compounds, and polymeric blends.
6. The composite fiber according to claim 1, wherein the polymer component comprises at least one material from the group consisting of polyester, polyethylene terephthalate, polypropylene, NYLON, elastane, acetate, rayon, acrylics, Vinalon, polylactic acid blends, polyethylene (low or high density), polyvinyl chloride (PVC), and polystyrene, or combinations thereof.
7. The composite fiber according to claim 1, wherein the fiber is configured as a single composition fiber having fiber units with a cross section that is one of circular, tri-lobal, multi-lobal and bow-tie shaped.
8. The composite fiber according to claim 1, wherein the fiber is configured as a multiple composition fiber having a cross section that is one of sheath/core, "islands in the sea" with a circular cross-section, tri-lobal cross-section, and multi-lobal cross-section.
9. The composite fiber according to claim 1, comprising at least two structural parts respectively containing different materials.
10. The composite fiber according to claim 1, wherein the fiber has a diameter between 5 and 100 microns.
11. The composite fiber according to claim 10, wherein the fiber has a diameter between 10 and 30 microns.
12. A sheet material comprising: a composite fiber containing a particle component and a polymer component, wherein discrete particles in the particle component impart to the composite fiber a specific gravity of at least 2.0; wherein the fiber is formed into a sheet and includes at least one of thread, solid nonwoven material, nonwoven material with perforations, mesh, and felt comprising said composite fiber.
13. The sheet material according to claim 12, wherein the sheet is a multi-layer construct comprising plural distinct layers, wherein a given said layer differs in properties from at least one other said layer, and that includes at least one of thread, solid nonwoven material, nonwoven material with perforations, mesh, and felt comprising a fiber distinct from said composite fiber.
14. The sheet material according to claim 12, further comprising a coating of particles on the sheet.
15. The sheet material according to claim 12, further comprising as least one of a layer, laminate and coating imparting at least one of non-stick properties, reduced coefficient of friction, chemical and corrosion resistance, electrical insulation, wear resistance, lubrication, heat-resistance, and water resistance.
16. The sheet material according to claim 12, wherein the composite fiber is one of knit and woven fabric to form a fabric.
17. The sheet material according to claim 12, comprising plural distinct layers, wherein a given said layer differs in properties from at least one other said layer.
18. The sheet material according to claim 12, wherein the fabric is structured to receive objects that are at least temporarily affixed.
19. The sheet material according to claim 18, wherein the objects are one of pocketed, zipped in and sewn in.
20. The sheet material according to claim 12, further comprising weights affixed to the fabric.
CROSS REFERENCE TO RELATED APPLICATION
 This application claims the priority of U.S. Provisional Patent Application Ser. No. 61/478,173, filed Apr. 22, 2011.
FIELD OF THE INVENTION
 The present invention relates to the technical field of polymeric composite fibers. More specifically, composites of polymeric materials with metal, glass, or other materials have found use in the fashion, automotive, and other industries for their desirable combinations of properties. Metal-polymer composites designed to exhibit physical properties of the metal as opposed to chemical are currently manufactured via either lamination or metallization, both of which construct shells of metal around or within the fiber.
BACKGROUND OF THE INVENTION
 Many industries have diverse needs for metal/polymer composites. This has led to the development of fibers with a wide range of different properties such as improved strength, abrasion resistance, antibacterial properties, and enhanced thermal properties. These fibers can then be fabricated into garments and other structures with a variety of characteristics, such as being cut resistant and having electromagnetic shielding properties.
 Additives have been commonly used within polymer matrices to give newly desired properties such as conductivity (U.S. Pat. No. 3,958,066), antimicrobial, and coloring. U.S. Pat. No. 5,897,673 discusses fibers containing fine metallic particles methods of production. However, those mentioned fibers contain the fine metallic particles throughout the fiber structure, whereas properties such as selective distribution and non-outer-surface contact are left desired.
 Heavy (high specific-gravity) fibers have been explored in the fishing industry. Two methods have been examined for fishing lines: composite yarns (US patent publication number US 2011/0173873 A1) and composite fibers (U.S. Pat. No. 6,671,997). The composite fiber method uses a core-sheath monofilament construct with high specific-gravity material in the core mixture.
 Prior art is limited on the creation and production of fibers containing excessive amounts of additives for properties such as increased weight. These properties are extremely desirable in the domain of commercial textiles, where demand exists for fabric made from high specific-gravity fibers for increased weight properties.
SUMMARY OF THE INVENTION
 It is an object of the present invention to provide particle/polymer composite fibers comprised of polyester, NYLON, elastane, and the like, and metallic or ceramic or other similarly dense or otherwise useful inorganic particles that can be easily formed into fabrics.
 The fabric is made either from the specially engineered particle/polymer composite fibers, or from polymeric fibers such as NYLON and elastane and the like, wound together with specially engineered metal-containing polymeric fibers. Particles of specific gravity 2 or higher, including but not limited to metals such as iron, zinc, or tungsten, alloys such as steel and brass, and metal-containing ceramics such as iron oxide or zinc oxide, are first compounded with one or more polymeric compounds suitable for the manufacture of synthetic fibers or fabrics. The present invention calls for particles about 25 μm or less in diameter or a third of the target fiber diameter, whichever metric is the lesser of the two, in order to protect the structural integrity of the fibers.
 The compounded material then undergoes a melt-spinning process and forms meta/polymer composite fibers. This results in the distribution of metal particles throughout the fiber in the case of a single-component fiber, or throughout the core/cores in the case of a multi-component fiber. The present invention also calls for the metal particles to make up about 75% or less of the fiber's mass. The exact percent composition varies with the desired density, tensile strength, and other properties of the fiber. The resulting fiber behaves similarly to a pure polymeric fiber, yet can reach specific gravities of 4.2 or higher, roughly 3 or more times that of similar-behaving pure-polymer fibers.
 As a further object of the present invention, these specially engineered fibers are then fabricated into fabric structures useful in many different applications. When evaluated for permeability to air, moisture wicking, flexibility, denier, strength, longevity, and elasticity, the fabric performs comparably to standard polymeric containing fabrics, yet is approximately three times as heavy due to the metallic particles.
 Properties of the specially engineered fibers and fabrics in the present invention, including but not limited to its density, conductivity, electromagnetic shielding, and resistance to cutting, can be varied arbitrarily with the identity of the particles and polymer, percent compositions of each component, and, in the case of multi-component fibers, the relative size of the different fiber components. This enables spatial variation of the density and other properties of the fiber and fabric to be targeted appropriately for the fiber or fabric's needs.
DESCRIPTION OF THE DRAWINGS
 Some of the objects of the invention having been stated other objects will become apparent with reference to the detailed description and the drawings as described herein.
 FIG. 1 cross-sectional depiction of simplistic custom composite fibers. The fiber in the figure is a monofilament fiber with a single polymer component and single inorganic component. Visible are inorganic particles of varying diameter, but none with diameter greater than a third of the fiber diameter, distributed evenly throughout the fiber cross section.
 FIG. 2 is an elevated side view of a composite fiber of the invention in which the inorganic component takes the form of microthreads distributed throughout the fiber. The microthreads can vary in length and continuity. Also, the polymer component of the depicted fiber is transparent in order to adequately depict the presence of the microthreads; the microthreads are not present on the outside of the fiber, but rather are distributed throughout.
 FIG. 3 is a side elevation cross-section view of possible multi-component fiber embodiments for the weighted and non-weighted components.
 FIG. 4 is a cross-section view of a simple weighted single component fiber where the black sections indicate the particles of specific gravity 2 or greater and 40-70% of the total fiber by weight.
 FIG. 5 depicts a sheath-core custom composite fiber in which the sheath and core each contain different polymer and inorganic components. For example, the figure accurately represents a sheath-core fiber in which the sheath comprises PET and small silver microparticles for comfort and anti-microbial properties, while the core comprises Nylon and larger, flake-like ferrous oxide particles for strength and weight.
 FIGS. 6 and 7 portray a solid nonwoven construction and a perforated nonwoven construction of the invention, respectively. The nonwoven material is the custom composite material of the invention.
 FIG. 8 portrays a multi-layer construct comprising plural distinct layers, wherein a given said layer differs in properties from at least one other said layer. The layers can be nonwoven or woven.
 FIG. 9 portrays a composite nonwoven sheet of the invention onto which an additional layer of inorganic particles has been deposited after extrusion. The particles reside on the exterior of the invention, but have become partially embedded within the invention and remain affixed as a result. These particles are in addition to those particles that may already be present during extrusion of the invention.
 FIGS. 10 and 11 portray a composite nonwoven sheet of the invention which has been laminated or otherwise coated on one or both sides, respectively. In the drawing, the laminate or coating optionally contains additional inorganic particles.
 FIG. 12 portrays a fabric of the invention knit or otherwise woven from custom composite threads.
 FIG. 13 portrays a fabric of the invention, either woven or nonwoven, to which objects have been affixed.
 It is an object of the present invention to provide metal/polymer composite fibers that can be easily formed into fabrics and structured lattices. As explained in greater detail below, the present invention is based on the discovery that a concentration of heavy micro-particles in polymeric fibers can maintain to a great extent some and/or all functional purposes of the structural and physical properties of the unaltered polymer fiber, with the sole exception higher specific gravity.
 The term "fiber" as used herein means both fibers of finite length, such as conventional staple fiber, as well as substantially continuous structures, such as continuous filaments, unless otherwise indicated. The fibers of the invention can be hollow or non-hollow fibers, and further can have a substantially round or circular cross section or non-circular cross sections (for example, oval, rectangular, multi-lobed, and the like).
 As used herein, the term "multi-component fibers" includes staples and continuous filaments with two or more discrete structured domains of deliberately different composition, as opposed to blends where the composition is uniform, dispersed, random or unstructured, including without limitation sheath/core and "islands in the sea" configurations.
 As used herein, the term "composite fibers" includes staples and continuous filaments composed of two or more materials, including but not limited to different polymers, metals, and ceramics.
 The term "thread" shall refer to multiple fibers wound together into a single continuous strand.
 The term "fabric" shall refer to a continuous sheet, either woven or non-woven, and of any number of layers, comprised of fibers or of materials suitable for fibers.
 Both the shape of the fiber and the configuration of the components therein will depend upon the equipment that is used in the preparation of the fiber, the process conditions, and the melt viscosities of the various components. A wide variety of fiber configurations are possible in the present invention. Generally, as illustrated in the figures, the fiber of the invention is a single or multi-component composite fiber comprised of but not limited to one or more polymeric materials and one or more metallic materials as specified below.
 The polymeric components can be selected from any of the types of polymers known in the art that are capable of being formed into fibers, including polyolefins, polyvinyl, polyesters, polyamides and the like. Examples of suitable polymers useful in the practice of the present invention include, without limitation, polyolefins including polypropylene, polyethylene, polybutene, and polymethyl pentene (PMP), polyamides including NYLON, such as NYLON 6 and NYLON 6,6, polyacrylates, polystyrenes, polyurethanes, acetal resins, polyethylene vinyl alcohol (including Vinalon), polyesters including aromatic polyesters, such as polyethylene terephthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, poly(1,4-cyclohexylene dimethylene terephthalate) (PCT), and aliphatic polyesters such as polylactic acid (PLA), polyphenylene sulfide, thermoplastic elastomers, polyacrylonitrile, cellulose and cellulose derivatives, polyaramids, acetals, fluoropolymers, copolymers and terpolymers thereof and mixtures or blends thereof.
 Further examples of aliphatic polyesters which may be useful in the present invention include, without limitation, fiber forming polymers formed from (1) a combination of an aliphatic glycol (e.g., ethylene, glycol, propylene glycol, butylene glycol, hexanediol, octanediol or decanediol) or an oligomer of ethylene glycol (e.g., diethylene glycol or triethylene glycol) with an aliphatic dicarboxylic acid (e.g., succinic acid, adipic acid, hexanedicarboxylic acid or decaneolicarboxylic acid) or (2) the self-condensation of hydroxy carboxylic acids other than poly(lactic acid), such as polyhydroxy butyrate, polyethylene adipate, polybutylene adipate, polyhexane adipate, and copolymers containing them.
 Aromatic polyesters include (1) polyesters of alkylene glycols having 2-10 carbon atoms and aromatic diacids; (2) polyalkylene naphthalates, which are polyesters of 2,6-naphthalenedicarboxylic acid and alkylene glycols, as for example polyethylene naphthalate; and (3) polyesters derived from 1,4-cyclohexanedimethanol and terephthalic acid, as for example polycyclohexane terephthalate. Exemplary polyalkylene terephthalates include without limitation, polyethylene terephthalate (also PET) and polybutylene terephthalate.
 Exemplary fibers of the invention include fibers in which the weighted component is formed of a polyolefin such as polypropylene, an aromatic or aliphatic polyester such as polyethylene terephthalate or polylactic acid, or a polyamide such as NYLON 6 or NYLON 6,6. Although not required, the non-weighted component of the fibers of the present invention can advantageously be formed of the same polymer as the weighted component.
 The metallic or metal-containing components can be selected from any that exhibit some or all properties fundamentally different from those of the polymer, including without limitation specific gravity, conductivity, electromagnetic shielding, heat resistance, cut resistance, elasticity, hardness, and tensile strength. Such metal or metal-containing compounds may include without limitation iron, bronze, brass, steel, titanium, tin, copper, tungsten, platinum, silver, bismuth trioxide, ferrous oxide, silver oxide, zinc, zinc oxide, lead, molybdenum, or any alloy or other blend or mixture thereof or related.
 Each of the polymeric components of the composite fibers of the invention can optionally include other materials with previously-noted benefits not adversely affecting the desired properties of the component. Exemplary materials that could be used as additional components include, without limitation, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, particulates, and other materials added to enhance processability or end-use properties of the polymeric components. Such additives can be used in conventional or unconventional amounts without falling outside the scope of the present invention.
 In order to manufacture the present invention, particles of approximately 25 μm diameter or less and specific gravity at least 2 or higher, including but not limited to metal alloys such as steel and brass, are first compounded with one or more suitable pre-polymeric or polymeric compounds, as defined above. The compounded material then undergoes a melt-spinning process and forms metal/polymer composite fibers. This results in the distribution of metal particles throughout the fiber in the case of a single-component fiber, or throughout the core/cores in the case of a multi-component fiber. In the present invention the high-density particles can account for up to about 75% of the fiber's mass. The exact percent composition varies with the desired density, tensile strength, and other properties of the fiber. After extrusion, the fibers are drawn using technology known to those experienced in the art to their final tensile strength and diameter, preferably between 5 and 100 microns in diameter, and more preferably between 10 and 30 microns in diameter.
 The density of the specially engineered fibers in the present invention can be varied arbitrarily with the identity of the particles and polymer, percent compositions of each component, and, in the case of multi-component fibers, the relative size of the fiber's different components. This enables different concentrations of weight centered in area(s) of the fabric targeted appropriately for the fabric's needs.
 The fibers of the present invention may be made from any of the known fiber forming methods including, but not limited to solution spinning for making fibers including rayon and Kevlar®, POY/FDY, or melt spinning. These and other methods for making composite fibers are well known and will only be discussed in minor detail.
 Generally, for melt-spinning multi-component composite fibers, at least two polymers are extruded separately and fed into a polymer distribution system wherein the polymers are introduced into a spinneret plate. In the present invention, the heavy micro-particles and at least one of the polymers can be mixed or blended prior to extrusion using known techniques. The particles can accordingly be distributed or dispersed substantially uniformly throughout at least one of the polymer streams fed into the spinneret plate. The polymers follow separate paths to the fiber spinneret and are combined in a spinneret hole. The spinneret is configured so that the extrudant has the desired overall fiber cross-section (e.g., round, oval, etc.).
 Following extrusion through the die, the resulting thin fluid strands, or filaments, remain in the molten state for some distance before they are solidified by cooling in a surrounding fluid medium, which may be, for example, chilled air blown through the strands. Once solidified, the filaments are taken up on a godet or another take-up surface. In a continuous filament process, the strands can be taken up on a godet which draws down the thin fluid streams in proportion to the speed of the take-up godet. In a spunbond process, the strands can be collected in a jet, such as for example, an air attenuator, and blown onto a take-up surface such as a roller or a moving belt to form a spunbond web. In a meltblown process, air is ejected at the surface of the spinneret which serves to simultaneously draw down and cool the thin fluid streams as they are deposited on a take-up surface in the path of cooling air, thereby forming a fiber web.
 Regardless of the type of melt spinning procedure used, generally the thin fluid streams are melt drawn down in a molten state, i.e., before solidification occurs, to orient the polymer molecules for good tenacity. Typical melt draw down ratios known in the industry may be utilized. The experienced engineer will appreciate that specific melt draw down is not required for meltblowing processes. Where a continuous filament or staple process is employed, it may be desirable to draw the strands in the solid state with conventional drawing equipment, such as, for example, sequential godets operating at differential speeds.
 Following drawing in the solid state, the continuous filaments may be mechanically crimped and cut into a desirable fiber length, thereby producing staple fiber. The length of the staple fibers generally ranges from about 25 to about 50 millimeters, although the fibers can be longer or shorter as desired.
 The multi-component fibers of the invention can be staple fibers, continuous filaments, or meltblown fibers. In general, staple fibers, multifilament, and spunbond fibers formed in accordance with the present invention can have a fineness of about 0.5 to about 100 denier per filament. Meltblown filaments can have a fineness of about 0.001 to about 10.0 denier. Monofilament fibers can have a fineness of about 50 to about 10,000 denier.
 The multi-component fibers of the invention are useful in the production of a wide variety of products, including without limitation nonwoven structures, such as but not limited to carded webs, wet laid webs, dry laid webs, spunbonded webs, meltblown webs, and the like. The nonwoven webs can be bonded to transform the webs into a coherent nonwoven fabric using bonding techniques known in the industry. Exemplary bonding techniques for nonwoven webs include mechanical bonding, such as hydroentanglement and needle punching, adhesive bonding, thermal bonding, and the like. An example of thermal bonding is through air bonding, although other thermal bonding techniques, such as calendaring, microwave or other RF treatments, can be used.
 Fibers other than the multi-component fibers of the invention may be present as well in any final product without falling outside the scope of the invention, including any of the various synthetic and/or natural fibers known in the art. Exemplary synthetic fibers include polyolefin, polyester, polyamide, acrylic, rayon, cellulose acetate, polyaramids, thermoplastic multi-component fibers (such as conventional sheath/core fibers, for example polyethylene sheath/polyester core fibers) and the like and mixtures thereof. Exemplary natural fibers include wool, cotton, wood pulp fibers and the like and mixtures thereof.
 Furthermore, it may be desirable to coat, laminate, or otherwise cover the outer and/or inner surfaces of threads or layers of material contained within any final product without falling outside the scope of the invention. This is a practice well known to those experienced in the art, and is commonly used to impart non-stick, low-friction, or additional chemical and heat resistance properties to the final product. However, additional non-polymeric particles identical, similar, or fundamentally different to the particles already contained within the composite fibers of the invention. These particles may impart without limitation both those properties unique to the invention and those known to be desirable by those experienced in the art. In addition to those benefits known by those experienced in the art, this coating or lamination allows the custom composite fibers of the invention to be customized to a greater degree, either by increasing the degree to which properties of the particles found within the fiber are represented, or by imparting additional properties of an alternative particle. Doing so in this manner avoids committing an additional fraction of the fiber's interior mass and volume to the non-polymeric particles. As a result, this higher degree of customizability comes with a lower penalty to the structural properties of the invention than would be experienced were a similar mass of additional particles contained within the fiber.
 As a further aspect of the invention, following extrusion but prior to coating or lamination, the fibers or other non-woven creations of the invention may be further coated, dusted, or otherwise induced to carry on the exterior of individual filaments or layers additional particles identical, similar, or fundamentally different to the particles already contained within the composite fibers of the invention. These particles may impart without limitation both those properties unique to the invention and those known to be desirable by those experienced in the art. This additional coating or dusting allows the custom composite fibers of the invention to be customized to a greater degree, either by increasing the degree to which properties of the particles found within the fiber are represented, or by imparting additional properties of an alternative particle. Doing so in this manner avoids committing an additional fraction of the fiber's interior mass and volume to the non-polymeric particles. As a result, this higher degree of customizability comes with a lower penalty to the structural properties of the invention than would be experienced if a similar mass of additional particles were contained within the fiber.
 These particles are most easily adhered to the outside of the filaments or layers of the invention using a process which passes the extruded filament or non-woven creation through an enclosed chamber, in which a fan system lifts and circulates the particles throughout the air contained within the chamber such that a fraction of the particles that contact the filament will adhere to the surface. These particles can then optionally be further adhered to the final product by use of previously-discussed lamination and/or coating techniques already known to those experienced in the art.
 In another embodiment of the invention, the fibers of the invention can also be used to make other textile structures such as, but not limited to, woven and knit fabrics. Yarns prepared for use in forming such woven and knit fabrics are similarly included within the scope of the present invention. Such yarns may be prepared from the continuous filament or spun yarns comprising staple fibers of the present invention by methods known in the industry, such as twisting or air entanglement.
 The invention discovered is a single or multi-component composite fiber with mechanical properties similar to those already achieved in polymeric fibers with the sole exception of a higher specific gravity, thus resulting in a heavier weight distributed throughout the fiber itself. The fiber is a thermoplastic fiber, preferably but not exclusively NYLON or polyester, having one or more multiple weighted and non weighted components, wherein the weighted component(s) is preferably isolated inside of the fiber. The weighted component is preferably between about 10%-95% by volume of the total multi-component fiber, and the weighted component preferably is comprised of between about 40%-75% by weight of particles with a specific gravity of 2 or greater. The particles with specific gravity of approximately 2 or greater will be approximately 1-10 micrometers in diameter on average, and made out of metals, metal oxides, organic and inorganic particles, magnetic particles, clays, activated carbon particles, carbon nanotubes, ceramics, glass, other such solid particles and combinations thereof. The multi-component arrangement of the fiber may be selected, without limitation, from the following arrangements: sheath/core, islands in the sea, segmented ribbon, side-by-side, bow-tie, segmented pie, and multi-lobal (with integrated islands) shapes; all different shapes are able to be combined for innovative fiber cross section designs. The weighted segment of the multi-component fiber can also be made independently to create a simple single component fiber with cross sections of a simple circular, ribbon, bow-tie, or multi-lobal fiber.
 Further, this novel multi-component weighted fiber may include another embodiment with the addition of extra particles for added properties and functionality while still falling within the scope of the present invention. In this embodiment, other particles may be used instead of or together with the particles of specific gravity of 2 or greater. That is, the same process may be used to incorporate other metals, metal oxides, organic and inorganic particles, magnetic particles, clays, activated carbon particles, carbon nanotubes, ceramics, glass and other such solid particles into the fiber to impart additional functionality. Therefore, additional functionality or multiple functionality (for example, antimicrobial properties) is achieved by the use of a multi-component fiber spinning system. For example, one component may contain silver microparticles in order to imbue antibacterial properties, and the other may have particles with a specific gravity of 2 or greater for added weight.
 In yet another embodiment of the invention, custom composite fibers of the invention are woven or otherwise used in the construction of fabric or fabric-like structures. The fabric performs comparably to standard polymers containing fabrics with respect to most attributes, such as strength, durability, and feel, yet like the fibers exhibits properties which deviate significantly from those normally associated with the polymeric material by those experienced in the art, these unique properties including without limitation high density, conductivity, electromagnetic shielding, cut-resistance, heat-resistance, and radiation shielding.
 Fabrics are typically woven from fibers and filament via knitting. Typically, the fibers begin on the spool onto which they were wound shortly following extrusion, and on which they were transported. Large automated looms pull the fibers gradually off the spool to be woven into pre-programmed patterns. The looms use a variety of moving parts which feed the filament back and forth through numerous extended metallic hooks, which then retract such that the fiber is knit into the portion of the fabric already constructed. Further detail is outside the scope of this invention, but is well known to those experienced in the art. Once knit, the fabric can be cut, sewn, and otherwise tailored towards its final purpose using techniques also known to those skilled in the art.
 In addition, the fabric of the invention may include multiple identical or unique homogeneous or heterogeneous layers of fiber without falling outside the scope of the present invention. Knitting fabric with multiple layers serves functions including, without limitation, increasing the strength, heat retention, moisture retention, durability, and total weight of the fabric or final product.
 Furthermore, the fabric of the invention may be manufactured, tailored, or otherwise altered or modified in design to exhibit other functional properties without falling outside the scope of the invention. These alterations or modifications may include without limitation micro-perforations, patches of alternative fabrics, seamless knitting, fashion-centric alterations, dyeing or other coloring, and snaps, zippers, or other pockets for the addition and removal of personal effects, weights, or other items to be carried or worn.
 Additionally, the fabric of the present invention may be woven using a variety of different knitting techniques, both those known and unknown to those experienced in the art, without falling outside the scope of the present invention, which may result in additional qualities or properties of the final product. For example, processes and machinery have been developed to knit at very high speeds, at very low amounts of stress on the fiber or fabric, and in seamless and/or circular patterns and arrangements.
 The following example(s) illustrates the previous explanation in terms of specified polymeric compounds and particles of a specified nature, but should not be considered in limitation of the invention.
 One possible demonstration of our technology is illustrated in the use of tungsten as a microparticle compounded into PET, a pre-polyethylene material. The tungsten comprises approximately 20% by volume of the total batch mixture of PET and tungsten for use in the core of a sheath-core fiber design. Using a standard compounding process, with the option of adding an antioxidant or metal deactivator, the tungsten was integrated into the PET pre-polymer beads. A standard melt-spinning process was then used to extrude the uniform pre-polymer blend into the core of a sheath core fiber, with the sheath comprising pure PET. The melt pumps for the sheath and core polymers are set to produce a ratio of 80%:20% of the cross sectional area of each fiber occupied by the polymeric sheath and weighted-mixture core, respectively.
 It will be understood that various details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation, of the invention being defined by the claims.
Patent applications in class SCRIM (E.G., OPEN NET OR MESH, GAUZE, LOOSE OR OPEN WEAVE OR KNIT, ETC.)
Patent applications in all subclasses SCRIM (E.G., OPEN NET OR MESH, GAUZE, LOOSE OR OPEN WEAVE OR KNIT, ETC.)