HK1230883B - Synthetic fill materials having composite fiber structures - Google Patents

Description

Synthetic filling material with composite fiber structure

Related applications

This application claims the benefit of and priority to U.S. Provisional Application Serial No. 61/973,527, filed April 1, 2014, and U.S. Provisional Application Serial No. 61/991,309, filed May 9, 2014, the contents of which are hereby incorporated by reference in their entirety as if set forth herein for all purposes.

background

The inventive subject matter disclosed herein generally relates to small-scale fiber units suitable as filling materials in articles of clothing, sleeping bags, bedding, pillows, padding, cushions, and other such articles and uses. In some embodiments, the inventive subject matter relates to a fiber construction suitable for use as a filling material for insulation or padding, comprising: a primary fiber structure comprising fibers of a predetermined length; and a secondary fiber structure comprising a plurality of short loops spaced apart along the length of the primary fibers. In some embodiments, the inventive subject matter relates to an insulating fiber construction that simulates the structure and dimensions of natural down and thereby provides similar properties.

Various natural and synthetic filling materials are known. Natural down, for example, from waterfowl, is an excellent filling material with many outstanding properties. Down is the feathers that form the undercoat of waterfowl (e.g., geese, ducks, or swans). It consists of lightweight, fluffy filaments that grow from a single feather point, but lack any feather shafts.

A key physical property of down is its loft, also known as bulk. Loft is the volume occupied by a given unit mass of material. Loft is the most common parameter used to differentiate between different grades of goose down used in consumer products. Materials with higher loft occupy a larger volume with less mass, and thus provide greater insulating properties. Because loft significantly impacts product value, strict guidelines and testing procedures exist to ensure consistent product labeling and performance. The International Down and Feather Laboratory (IDFL) conducts extensive testing and classification in the United States on raw down material imported from around the world for sale. A piston-cylinder system is used to determine loft. Detailed instructions and procedures for this test are available on the IDFL website (IDFL 2004). Test standards vary worldwide; however, the principles of interpretation and testing remain the same. For the purposes of this patent specification, the International Down and Feather Bureau (IDFB) establishes test methods and other standards for the international community. Unless otherwise specified, all IDFB standards and definitions as of January 1, 2014, apply to this specification. (The standards and definitions are publicly accessible on the IDFB website, http://www.idfl.com/)

The attributes of down that make it so popular as an insulator are its light weight, softness, compressibility, recovery, elasticity, and breathability.

However, natural feathers or down have several disadvantages. For example, because they are easily damaged by insects and microorganisms, many steps are required to process natural feathers or down. Because they are only available in limited quantities, natural feathers and down are also expensive. The handling and care of the animals used to produce them can also raise animal welfare concerns. In addition, down or feathers can cause allergic reactions in some users. In wet conditions, down can become filled with water. When this happens, the down loses its loft, compresses, and therefore loses its key insulating properties because the down can no longer trap air spaces for warmth. Because of this, synthetic down alternatives are constantly being sought. This and other issues have prompted research into new fiber materials to develop alternatives to natural feathers or down.

Some prior art methods for making down substitutes include various ways of bundling and bonding short fibers; forming fibers into spheres; and agglomerating fibers through electrodeposition. In another method, disclosed in U.S. Patent 7,261,936, a down substitute in the form of a fir tree or branch-like structure is made from multifilament fibers that have been melt-cut into short segments so that the individual filaments are fused together at one end and free at the other. In yet another method, disclosed in EP 0,620,185, a down substitute comprises an elongated support structure with a generally dispersed array of discrete fine fibers, one end of which is attached to the support structure and the other end of which is free.

However, no such prior art materials are sufficiently comparable in physical properties to natural down materials.Due to the complex structure and physical properties of down, replicating the properties of natural down has been particularly challenging.

Figure 1A and Figure 1B schematically illustrate the general structure of a natural down cluster 1 (Figure 1A). Down clusters can be in the range of about 5mm to about 70mm in diameter. They have a central node or root, which has many lines 2 extending outward in all directions. Independent lines can be referred to as "primary" structures or fibers 3. The primary structure 3 has many fine structures extending outward along its length, which can be referred to as "secondary" structures or fibers 4. The primary structure 3 has a length of 3mm-33mm, and a typical length is about 14mm-20mm. The primary structure of natural down usually has about 50-1500 secondary fibers 4 (Figure 1B) arranged radially along its length. When the length is 33mm, and the spacing is 60 μm, 550 secondary fibers are produced, or if each side is counted separately, 1100 secondary fibers are produced. When the length is 3mm, and the spacing is 60 μm, 50 secondary fibers are produced, or if each side is counted separately, 100 secondary fibers are produced. The natural down may also have one or two relatively short tertiary fibers (not shown) spaced along the length of each secondary fiber 4 and extending from each secondary fiber 4 every approximately 100 microns.

The secondary structure length of natural down, generally designated "D" in the figures, can range from 0.35 mm to 1.4 mm, with a typical length of 0.55 mm to 0.75 mm. The secondary fibers are highly elastic and resistant to permanent deformation, and they are capable of storing elastic energy. Figures 1A and 1B show representative fiber dimensions, which can vary substantially.

Besides the inherent challenges in replicating the physical structure of down, down substitutes are considered difficult to manufacture continuously and at low cost.

In view of the above-mentioned needs and shortcomings, there is a great need for improved filling materials, particularly insulating materials that more closely replicate the properties of natural down and are commercially viable to manufacture.

Overview

The inventive subject matter disclosed herein overcomes the above-mentioned and other shortcomings of the prior art. Advantages of the inventive subject matter over natural down or attempted synthetic down may include, but are not limited to, any one or more of the following: lower production costs, water resistance, avoidance of animal welfare concerns, improved heat retention properties, improved loft or reloft, and an improved tactile feel that better simulates the feel of natural down.

In some embodiments, the present subject matter relates to a fiber construction suitable for use as a fill material for insulation or padding, comprising: a primary fiber structure comprising fibers of a predetermined length; and a secondary fiber structure comprising a plurality of relatively short loops spaced along the length of the primary fibers. In some embodiments, the present subject matter relates to an insulating fiber structure that mimics the structure and dimensions of natural down and thereby provides similar properties.

Thermal insulation materials may be used in a variety of applications requiring insulation and/or padding, including garments and clothing, sleeping bags, blankets, duvets, and the like.

The present subject matter also relates to related methods, systems, and apparatus for making the fiber constructions of the present invention.

These and other embodiments are described in more detail in the following detailed description and accompanying drawings.

The following is a description of various inventive production lines according to the present subject matter.The appended claims, as originally filed in this document, or as subsequently amended, are hereby incorporated into this Summary as if written herein.

The foregoing is not intended to be an exhaustive list of embodiments and features of the subject matter of the present invention. Other embodiments and features will be apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate embodiments according to the inventive subject matter, except where indicated to illustrate prior art.

Figure 1A shows a representative natural down tuft.

Figure IB schematically illustrates a natural down tuft, showing the primary and secondary structures.

FIG. 2A schematically illustrates one possible synthetic construction of primary fibers and associated secondary fibers that simulates a natural down cluster.

FIG. 2B schematically illustrates a synthetic construct having an alternative arrangement of primary and secondary fibers that simulate clusters of natural down.

FIG. 2C schematically illustrates a synthetic construct having another alternative arrangement of primary and secondary fibers that simulates clusters of natural down.

FIG. 3 schematically illustrates a synthetic construction having yet another alternative arrangement of primary and secondary fibers that simulates clusters of natural down.

FIG4 schematically illustrates an embodiment of a composite construct in which loops of secondary fibers extend from a primary fiber in two principal directions or planes.

FIG. 5 schematically illustrates an alternative embodiment of a composite construct in which the secondary fibers are twisted or helically arranged about the primary fibers.

FIG6 schematically illustrates an alternative embodiment of a composite construct in which loops of secondary fibers may extend randomly in all directions from the primary fibers.

FIG. 7 schematically illustrates an alternative embodiment of a composite construct in which the loops of secondary fibers are arranged in a regular or uniform pattern.

FIG8 schematically illustrates an alternative embodiment of a composite construct having a less regular or non-uniform arrangement.

9 schematically illustrates an alternative embodiment of a composite construct in which two or more secondary fibers forming a loop are positioned on a single primary fiber while maintaining the same or overall ratio of primary to secondary fiber lengths, or other desired ratio.

10 schematically illustrates an alternative embodiment of a composite construct in which the secondary fiber portions defined by a straight or approximately straight line L passing through the intersection of the respective loops and the outwardly extending legs of the respective loops may form a pair of supplementary angles with the primary fibers.

FIG. 11 schematically illustrates components of one possible system for producing fibers for a synthetic construction simulating natural down.

FIG. 12 schematically illustrates components of an alternative embodiment of a system for producing fibers of a synthetic construction that simulates natural down.

FIG. 13 schematically illustrates components of an alternative embodiment of a system for producing fibers of a synthetic construction that simulates natural down.

FIG. 14 schematically illustrates components of an alternative embodiment of a system for producing fibers of a synthetic construction that simulates natural down.

FIG. 15 schematically illustrates components of an alternative embodiment of a system for producing fibers of a synthetic construction that simulates natural down.

Figure 16 schematically illustrates a finished product (in this case a jacket) having compartments containing a volumetric fill material composed of cells of a synthetic construction simulating natural down.

FIG. 17 schematically illustrates components of an alternative embodiment of a system for producing fibers of a synthetic construction that simulates natural down.

Detailed description

Representative embodiments according to the present subject matter are shown in Figures 2A-17, where identical or substantially similar features share common reference numerals.

The present subject matter generally relates to novel structures, assemblies of such structures, and methods of producing such structures for use as fill materials for insulation or other volumetric material applications such as padding or cushioning. The materials can be used as down substitutes with many advantages over down.

In accordance with the present subject matter, the fill material is comprised of a construction of composite material 10 of a primary fiber 12 and a plurality of linked secondary fibers 14 arranged in a plurality of two- or three-dimensional loops along the length of the primary fiber.

As used herein, "fiber" is a general term that may refer to filaments in the meter range, staple fibers in the centimeter or millimeter scale, or fibrils in the micrometer or nanometer scale. A fiber may be a single filament or a bundle of filaments.

As used herein, "ultrafine" fiber refers to a fiber with an average diameter (or other major cross-sectional dimensions in the case of non-circular fibers) of micron-scale to nanometer scale. As used herein, "micron-scale" refers to a fiber with an average diameter in the range of double digits or single digit microns to as low as about 1000 nanometers. In the textile industry, nanometer-scale fibers have an average diameter in the range of about 100-1000 nanometers or less. In certain embodiments, ultrafine fibers show a high aspect ratio (length/diameter) of at least 100 or higher. Ultrafine fibers can be analyzed by any method known to those skilled in the art. For example, a scanning electron microscope (SEM) can be used to measure the size of a given fiber.

Unless the context indicates otherwise, all dimensions are the mean of the indicated item, and/or if more than one item is referenced, all dimension sizes are the mean of the set of those items. For example, the diameter of a secondary fiber 14 is the average diameter taken from one end point to the other or from one intersection 14B to the opposite intersection 14C on the same loop 16. The diameters of multiple secondary fiber loops are determined by first determining the mean diameter of a single loop in a group of loops, and then obtaining those values for the group of loops and averaging those values.

The primary and secondary fibers 12, 14 can be coupled in various ways as described, and can include direct attachment of the primary and secondary fibers, such as by selecting a thermoplastic material as the primary and/or secondary fiber material and fusing these fibers together. Alternatively, the fibers can be coupled indirectly using a bonding agent, such as an adhesive.

The novel construct 10 according to the subject matter of the present invention can be characterized by a primary fiber 12 that is elongated in form and is the primary structure. The primary structure has been provided with a plurality of transversely extending secondary fibers 14 along its length that form a secondary structure in the nature of a loop 16, with one closed end or maxima 14A of a given loop defined by a section of the primary fiber extending transversely from the intersection 14B, 14C of the secondary fiber with the primary fiber 12. In certain embodiments, the loops 16 alternate along the length of the primary structure so as to provide a sinusoidal or wavy pattern with positive and negative extreme points along a baseline, with the primary structure serving as the baseline. This can be seen, for example, in Figures 2A and 2B and 3.

In certain possible embodiments, the loops 16 are formed in a multi-loop pattern by arranging continuous lengths 114 of secondary fibers in a desired pattern (e.g., a sinusoidal or wavy pattern) over a predetermined length 112 of primary fibers. The method of producing such a structure is discussed in more detail below. Because the secondary fibers 114 form a series of loops 16, rather than a set of discrete linear branches as in the prior art, the formation of the loops creates a larger surface that helps to keep the primary fibers separate. It is believed that the loops provide a function similar to the tertiary hooks of natural down, thereby allowing for synthetic down that more closely resembles natural down. Therefore, the main advantage anticipated by the subject matter of the present invention is improved loft.

In some embodiments, the loops of secondary fibers may be oriented entirely or preferentially along one side of the primary structure. An example of this can be seen in Figure 2C.

The primary structure and the secondary structure can be the same material or different materials. In some embodiments, the primary fibers have a higher stiffness, tensile strength and/or a higher thickness relative to the secondary fibers.

The loops 16 in the secondary structure are not limited to any specific shape or geometry. For example, they can be elliptical semicircles, polygons, compound curves or any other closed loop forms with endpoints diverging on the main structure. Any given loop 16 can have a symmetrical, uniform, asymmetrical or irregular shape. The size and/or spacing of the closed loops can be consistent or inconsistent along the main structure. The arrangement of the secondary structure can be a two-dimensional or three-dimensional shape around the main structure. The amplitude or length D of the loop measured perpendicularly to the main fiber from the intersection 14B, 14C or between the intersection 14B, 14C to the extreme point 14A can be consistent for each loop along the length of the main structure, or it can vary from one loop to another, as shown by _D1 , _D2 , _D3 , wherein each _D1 , _D2 and _D3 is a different value.

The following figures (FIGS. 4-9) are top and/or side views along the longitudinal axis of the composite primary/secondary fiber structure 10, conceptually illustrating various possible configurations of the composite structure.

FIG. 4 shows an example in which loops 16 of secondary fibers may extend from the primary fibers 12 in two principal directions or planes.

Figure 5 shows an optional embodiment in which a twist in the primary fiber 12 (or a helical rotation of a secondary fiber around the primary fiber) can cause the secondary fiber to form a twisted or helical structure (in which the extension angle of the secondary fiber varies linearly with its position along the z-axis of the primary fiber).

Figure 6 shows an alternative embodiment in which loops 16 of secondary fibers may extend randomly in all directions from the primary fibers.

FIG. 7 shows an alternative embodiment in which the loops 16 of secondary fibers may be arranged in a regular or uniform pattern.

Figure 8 shows an alternative embodiment where a less regular or uneven arrangement would be appropriate.

Figure 9 shows an alternative embodiment where two or more secondary fibers 14.1 and 14.2 forming loops 16.1 and 16.2 can be positioned onto a single primary fiber 12 while maintaining the same or overall ratio of primary to secondary fiber lengths or other desired ratios.

The secondary fiber portions defined by the line or approximate line L passing through the intersection 14B or 14C and the outwardly extending legs of the corresponding loops can form a pair of supplementary angles with the primary fibers 12, as seen in FIG10 . One supplementary angle can be an acute angle similar to the angle of the secondary fibers in natural down, which is in the range of 30 to 60 degrees, and more specifically, in the range of about 40 to 45 degrees. All loops 16 can also be arranged to have such angles.

In various embodiments disclosed herein, the primary and secondary structures can have the same or different materials or physical properties. They can have the same or different diameters or deniers. For example, the diameter of the primary fibers 12, 112 can generally be larger than the diameter or denier of the secondary fibers. However, diameter is not necessarily a determining aspect of fiber properties. For example, if the primary fibers are made of a stronger or harder material than the material from which the secondary fibers are made, the primary fibers can have a smaller diameter.

In some representative embodiments, the main fibers may have a diameter of about 10 μm to 100 μm. Diameters equal to or less than about 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, or 15 μm are contemplated for the main fibers. Diameters of 20-30 μm are expected to mimic those of natural down. For some applications where weight reduction is important, by selecting a relatively large diameter, the fibers will add unnecessary weight to the insulation. On the other hand, by selecting a relatively small diameter, the fibers may not be stiff enough to provide the necessary loft and resilience.

In some representative embodiments, the secondary fibers 14, 114 may have a diameter of 0.5 μm to 100 μm, and more particularly, diameters of about 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 11 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, or 0.5 μm are contemplated. In the event that any fiber has a non-uniform diameter, the diameter may generally be considered an average diameter, obtained by statistically sampling the diameters along the length of the fiber. A diameter of 1 μm-3 μm is expected to mimic the diameter of the secondary structure in natural down. If the diameter is less than about 1-3 μm, the fiber may not be effective in preventing radiative heat loss, but nano-sized fibers have been included to capture air spaces and reduce convective airflow. If the diameter is greater than about 12 μm, the warmth to weight ratio of the insulation may not be optimal. However, good commercial insulation has been made with fiber diameters up to 25 μm and higher (e.g., Primaloft ^™ insulation), so structures with fibers at or around 25 μm may still be suitable in some applications.

The present subject matter is not necessarily limited to any given size or size ratio or other measurement specifically recited, and quantities and values above or below the values, limits or ranges, as well as between the values, limits or ranges, may also apply. The denier of the primary or secondary fibers may be 6D or less.

The ratio of the primary fiber diameter to the secondary fiber diameter (the "aspect ratio") can vary. Suitable ratios include from about 1:1 to 100:1. A ratio of about 6:1 to 30:1 can mimic the ratio found in natural down. As noted above, the aspect ratio can also be less than 1, particularly if the primary fibers are made of a material with higher strength properties than the material used for the secondary fibers.

The fine fiber portion is intended to contribute to thermal insulation, while the coarser fiber portion contributes to the elastic structure for loft. Because the two are tightly connected, as in down, relofting properties are improved. The loops of fine secondary fibers are expected to keep the coarser primary fibers separate and help prevent irreversible entanglement. One consideration that can be addressed empirically when designing a suitable construction for a synthetic down unit is making the secondary fiber structure sufficiently strong so that it is not too fragile to effectively eliminate spaces for air entrapment.

Forming secondary fiber structures onto supporting primary fibers

Various methods can be used to produce units of fiber constructs according to the inventive subject matter described herein. Each construct is composed of a composite of a primary fiber and connected secondary fibers arranged in a plurality of two-dimensional or three-dimensional loops along the length of the primary fiber. Typically, the composite fiber is a monolithic structure formed by fusing the materials used for the primary and secondary fibers. As noted above, the primary and secondary fibers can have diameters ranging from less than 1 mm to nanometers.

The inventive subject matter contemplates novel production methods generally based on positioning a molten, softened, or solid secondary fiber material 114 in a desired pattern on a molten, softened, or solid primary fiber material, which produces the composite fiber structure 10 disclosed and contemplated herein. The pattern can be produced by the relative movement of a stream of secondary material over a stream or structure of primary fiber material. As used herein, "stream" refers to a filamentous flow of material in any state, such as a liquid, softened, or solid state. An example of a stream material is a moving yarn being drawn onto or from a spool. As used herein, a "structure" of a fiber in the context refers to a solid phase filamentous material, which can be dynamic, such as in a stream, or static during the processing steps contemplated herein.

Fiber formation methods that may be suitable for use in producing such relative motion include electrospinning, meltblowing, meltspinning, force spinning, or other methods that produce a composite fiber structure from the primary fibers 112 and the secondary fibers 114. The secondary fibers may be patterned not only into loops, but also into linear or curved structures that intersect with the primary fibers.

Fibers, such as ultrafine fibers, can be produced by forced jetting of selected fiber-forming materials through an ejector with a tiny outlet port. For example, the meltblowing process involves heating and extruding a thermoplastic fiber-forming polymer through a tiny outlet port in a meltblowing die. The molten polymer is then subjected to a converging stream of high-speed gas, such as air, to rapidly attenuate the polymer into small, microscale, or ultrafine fibers having a diameter smaller than that of the outlet port in the die. The gas has a temperature higher than or equal to that of the molten polymer and blows toward the molten polymer in the direction of flow. In this way, the high-speed gas also moves the resulting fibers toward a collector. Ambient air cools and solidifies the collected molten fibers. The meltblowing process can directly convert polymer resins into filaments or fibers in a single, integrated process. In a typical method, the polymer is stored in a hopper in the form of beads, pellets, or chips. An extruder shaft or screw pushes the polymer from the feed hopper into the melting section. The polymer is then exposed to the gradually increasing temperatures in the continuous heating zones in the extruder. As the polymer passes through the extruder, the molten material is heated until it reaches the final desired meltblowing temperature before being pushed through the meltblowing die.

According to a possible embodiment of the subject matter of the present invention, the extrusion device includes an ejector capable of ejecting fluid, softened or solid materials. For example, the ejector can be a pair of nozzles or a die, each of which is connected to a supply source, such as a pipeline supplying a flowable fiber-forming material. The pipeline can in turn be connected to a supply source of thermoplastic material, such as a hopper for such material. One nozzle is connected to a supply source containing the material for producing the main fiber 112. Another nozzle is connected to the same or different supply source containing the material for producing the secondary fiber 114. The system may include a pressurized source, such as a compressor or a gas, to drive the flowable material through the nozzle or the die. In some embodiments, the ejector can be a guide or port for a supply of material for winding, such as a spool of yarn or other filamentous material.

Process parameters include varying the properties of the material used to produce each fiber type and varying the shape and size of the exit orifice on the nozzle that ejects the flowable fiber-forming material. The exit orifice on the nozzle may be associated with a port for pressurized gas that converges on the material stream 112 or 114 to taper it to a diameter smaller than the exit orifice diameter.

Referring to FIG11 , the ejectors, such as a pair of nozzles 18 and 20, are spaced so that they blow or extrude the fiber-forming material streams 112, 114 in the form of closely spaced streams. More specifically, the ejectors are arranged so that their respective fiber materials flow in substantially the same direction, for example, from parallel (0 degrees) to a cross angle of up to 90 degrees, so that one stream can converge on the other in a back-and-forth manner or in a partially or completely circumferential manner. As noted below, convergence of streams ejected in parallel or at angles greater than 90 degrees can still be achieved using directed airflow directed at one or both streams.

The nozzle 20 for secondary fibers is rotatable and/or arranged to rotate relative to the nozzle for main fibers. When the nozzle rotates, the flow of secondary fiber-forming material 114 rotates around the flow of main fiber material 112 and entangles with the flow of main fiber material 112, thereby producing a loop 16 of secondary fibers along the length of main fiber 112. The spacing of the intersections of the loops and the size of these loops can be controlled by, for example, changing the angle of the flow of one or two nozzles relative to the flow of another nozzle, changing the speed of relative rotation and the spacing between one stream and another stream. Other control methods include generating directional air or other airflow in the processing area, which is applied to the molten or softened thermoplastic against the fiber material flow 114 or 112. The mechanism for guiding the airflow includes positive and negative pressure systems, such as fans, vacuum and pressurized gas sources. The airflow can be directed at any required angle against one or two streams so that the flow is redirected and a desired convergence angle is produced.

In a variation of the above system, the primary fiber can be a preformed structure and the secondary fiber material stream 114 can be caused to rotate about it. For example, the nozzle 20 for the secondary fiber-forming material 114 can be arranged so that it simultaneously rotates and moves up and down the length of the preformed primary fiber 112, producing a spiral of material in the form of a loop along the length of the primary fiber that is entangled with the primary fiber. The primary fiber 112 can be in a flowing or stationary state.

The secondary fiber-forming material 114 can be a thermoplastic material fusion bonded to the primary material, which can also be a thermoplastic material. One material can have a different melting or glass transition temperature relative to the other, or they can have the same such properties.

Alternatively, a chemical adhesive can be applied to the surface of one or both of the primary fibers 112 or the secondary fibers 114, so that the two are bonded together upon contact. Similarly, bonding can be achieved through a curing process using a polymeric material that reacts under specific conditions, such as UV wavelengths of light or ultrasonic energy. The advantage of ultrasonic energy is that it can act on the intersections 14B and 14C of the primary and secondary structures without adding heat that could melt or soften and change the shape of one or both of the overall structures.

Although the foregoing embodiments may illustrate a single nozzle for jetting the stream of secondary fiber-forming material 114, those skilled in the art will readily recognize from the teachings herein that multiple nozzles 20 may be used and arranged to rotate about the stream or other structure of primary fibers 112.

The foregoing description focuses on methods for producing a 360-degree rotation of the secondary fiber-forming material around a primary fiber stream or structure. However, any desired degree of rotation may be used. For example, the nozzle 20 for the secondary fiber stream may be rotated 45 degrees, 90 degrees, 180 degrees, or 270 degrees relative to the primary fiber stream or structure so that the loop 16 is preferentially formed on one side of the primary structure.

Another method for producing two-dimensional fibers is to direct a stream or structure 114 of secondary fiber material back and forth along the length of the stream or structure 112 for the primary structure, thereby producing a two-dimensional, generally sinusoidal, loop pattern on one side of the primary fiber, such as seen in FIG. 13 .

Another method for producing a complete or partial encirclement of spaced secondary fibers along and completely or partially around the main fiber can be achieved by elastically twisting the main fiber before or during the application of the secondary fibers so that the secondary fibers are arranged at different points along the circumference of the main fiber. By using an elastic main fiber material, the fibers are untied so that the secondary fibers are arranged in this way. In this method, the secondary fiber material needs to be applied only along one side of the main fiber; there is no need for rotation of the ejector for the secondary fiber material, but only a relative movement of the secondary fiber material up or down along the length of the main fiber material is required. The movement can also be carried out back and forth across the main fiber material. In any case, the movement is limited to a single plane.

Referring to Figure 12, in another possible embodiment, the path and nature of the joining of the secondary fibers to the primary fibers are controlled by electrostatic forces in an improved electrospinning process. A typical system includes: a high voltage source connected to a syringe or needle, which is connected to a source of fluid fiber-forming material 114. An electric field is generated to charge the needle or syringe at a nozzle portion having one or more ports from which the fluid is discharged. Electrodes for concentrating, diverting and directing the discharged solution are positioned below the needle or syringe. The electrodes help to guide/draw the fluid into micron- or nanometer-sized fibers from the nozzle and onto a collector, which can be a stationary element such as a tray, or it can be a dynamic element, such as a continuously moving belt or roller.

According to the subject matter of the present invention, the flow of the secondary material 114 from the ejector 22 is subjected to an alternating electrostatic field from the electrodes 24, 26 so that the flow is spirally wound around the main fiber flow or structure 112 and entangled with the main fiber flow or structure 112. Another method can be to extrude the flow in a sinusoidal form within the electrostatic field on top of the main fiber flow. Various known parameters for electrospinning can be used to control the required properties and size of the fiber. These parameters include: the charge of the spinning material and the spinning material solution; solution delivery (usually a material flow ejected from a syringe); charging at the flow; discharge of the filament at the collector; external forces (e.g., spiral rotation, rotation, fluctuation) from the electric field on the dynamic flow or static flow; the density of the discharge flow; and the voltage of the electrodes and the geometry and any dynamic characteristics of the collector. Those skilled in the art will understand how these parameters can be empirically used to produce the synthetic down of the present invention disclosed and contemplated herein.

The aforementioned embodiments of the spinning nozzle and electrospinning can also be combined into one system.

In another embodiment of the subject matter of the present invention, a composite structure of primary and secondary fibers is manufactured using a mechanical system that positions the secondary fibers against the primary fibers in a desired pattern, for example, those disclosed and contemplated herein. The positioned fibers can be shaped and coupled into a desired pattern by, for example, a compression shaping mechanism and/or other mechanism such as described elsewhere herein. For example, thermal energy or an adhesive can be used to connect the fiber portions to each other. Figures 13-15 show details of a representative mechanical system according to the aforementioned embodiments. In these examples, a filament 112 of primary fiber material is fed into a gap 30 between rollers 32 and 34, the gap 30 being sufficiently spaced apart so as to receive and stretch the primary and secondary fibers at their initial size or at a compressed smaller size that defines the initial size. The primary fibers 112 are fed perpendicular to the axis of rotation of the rollers 32, 34. The secondary fibers 114 are fed onto the primary fibers parallel to the longitudinal axis of the primary fibers or otherwise transverse to the longitudinal axis of the primary fibers. The secondary fibers can be a fiber stream in a molten, softened or solid form. The secondary fibers 114 can be fed from any mechanism or system for providing a flow, such as a meltblown system or a force spinning system discussed elsewhere herein. Similarly, the main fibers 112 can be provided from such a source. In order to position the secondary fibers relative to the main fibers, directional air or other gases and/or physical guides can be used. For example, the directional airflow can be adjusted suddenly so that the secondary fibers fluctuate back and forth on the main fibers. The combined main and secondary fibers are stretched through rollers and shaped together by compression and/or fusion bonding. The composite structure has a main trunk of the main fibers and an outward ring formed by the secondary fibers. The overall composite structure is roughly planar. However, as noted above, in other embodiments, the main fibers can be elastically twisted so that the secondary fibers are oriented around the fibers in multiple planes.

In another possible embodiment, the fiber material stream is ejected using force spinning or melt spinning. Force spinning is a method of using centrifugal force to stretch the fibers to extrude ultrafine fibers. The outlet port for the ejector is configured with a certain size and shape to encourage a thin stream 112 or 114 of fluid material to form when leaving the outlet port. As used herein, the outlet port refers to the outlet hole plus any associated channel or passage that supplies the outlet port and is used to define the properties of the discharged fiber-forming material stream. Due to factors such as surface tension, fluid viscosity, solvent volatility, rotational speed, etc., the ejected material can be solidified into ultrafine fibers with a diameter significantly smaller than the inner diameter of the outlet port. In this article, the flowable material is discharged from the outlet port as a stream that is solidified into fibers and can be referred to as "stream extrusion". The discharged material stream is directed to a collector, where the discharged material is gathered for use in the final product.

In certain embodiments, the rotary device applies centrifugal force on the fiber-forming material to cause flow extrusion and fiber formation thereby. The force applied on the source material can come from various systems and technologies that do not require an applied electric field, such as in electrospinning. For example, U.S. Patent Nos. 4937020, 5114631, 6824372, 7655175, 7857608, 8231378, 8425810 and U.S. Publication No. 20120135448 teach various devices and methods for forcibly discharging fiber-forming materials through the outlet port on the rotary device. The collection of the above-mentioned patent documents includes the disclosure of a system for producing fibers with an average diameter in the micron or nanometer range. For all purposes, the above-mentioned patent documents are incorporated herein by reference in their entirety. The optional method of the rotary system is a non-rotating pressure feed of the fiber-forming fluid based on the outlet port, which produces a fluid stream formed into a fiber. For example, US Patent No. 6,824,372, which is incorporated herein by reference in its entirety for all purposes, discloses a chamber that applies a jet force on a fiberizing fluid contained therein through oscillatory pressure variations produced by movable walls of the chamber.

Methods and apparatus for force spinning are known to those skilled in the art through various known teachings, such as some of the patent documents listed above, and through commercial equipment suppliers, such as FibeRio Technology Corporation of McAllen, Texas, USA, which provides a line of force spinning equipment (see http://fiberiotech.com/products/forcespinning-products/). Therefore, a detailed description of force spinning is unnecessary, and only a brief description will be provided herein.

With reference to Figure 17, a force spinning system for producing fine fibers 112 or 114 is shown. The system includes a spinneret connected to a source of a fluid or flowable material ("fiber-forming material") that can form fibers. The material source can come from a supply source, such as a reservoir or hopper for continuously feeding the spinneret. The spinneret itself can include a reservoir or hopper for the material that rotates with the spinneret.

The flowable material can be a molten material or a solution of the material. The spinneret is mechanically coupled to a motor that rotates the spinneret in a circular motion. In certain embodiments, the rotating element rotates within a range of about 500 to about 100,000 RPM. In certain embodiments, the rotation during which the material is ejected is at least 5,000 RPM. In other embodiments, it is at least 10,000 RPM. In other embodiments, it is at least 25,000 RPM. In other embodiments, it is at least 50,000 RPM. During rotation, the selected material, such as a polymer melt or a polymer solution, is ejected into the surrounding atmosphere as a material stream from one or more outlet ports on the spinneret. Outward radial centrifugal forces stretch the polymer stream as it exits the outlet ports, and due to its dependence on rotational inertia, the stream travels in a curved trajectory. The stretching of the extruded polymer stream is considered important in reducing the stream diameter over the distance from the nozzle to the collector. The ejected material is expected to solidify into ultrafine fibers when it reaches the collector. The system includes a collector for collecting the fibers as needed. For example, the fibers may be ejected from the spinneret onto a surface disposed below the spinneret or onto a wall opposite an outlet port on the spinneret.The collecting surface may be stationary or movable.

The fibers can be directed into a linear stream by a directional airflow and used in a manner similar to other streams or structures for the main fibers disclosed elsewhere herein. For example, the ejector for the secondary fibers can be directed so that it moves around the stream of the main fibers or moves back and forth on the stream of the main fibers. Alternatively, the main fiber stream can be directed onto a continuous belt. In this embodiment and any other embodiment, the movable flat surface can be part of a continuous belt system that feeds the fiber material to a roller or to other processing systems. The fibers can be directed into a linear stream or a roughly parallel fiber stream by a directional airflow and used in a manner similar to other streams or structures for the main fibers disclosed elsewhere herein. For example, the ejector for the secondary fibers can be directed so that it moves around the longitudinal axis of the main fibers collected in a linear or parallel manner on a conveyor belt or winding device or moves back and forth on the longitudinal axis of the main fibers collected in a linear or parallel manner on a conveyor belt or winding device. Alternatively, the main fiber stream can be directed onto a continuous belt. A secondary fiber stream of molten, softened or solid material can be placed on the main fibers, which can be in a molten, softened or solid form on the belt. The composite structure can be fed into a compression setting roll. The roll can be heated to facilitate fusion bonding of the primary fibers and the secondary fibers.

As with other methods disclosed herein, a stream of secondary fibers, which may be molten, softened, or solid material, may be placed onto the primary fibers, which may be in molten, softened, or solid form on a belt or another collector. The composite structure may be fed into a compression setting roll. The roll may be heated to facilitate fusion bonding of the primary and secondary fibers.

In any given system for producing composite fibers, the secondary fibers 114 can be positioned and shaped in a transverse pattern on the primary fibers 112 in a non-looped form. For example, linear or curved segments of secondary fibers can be placed onto and bonded to the primary fibers by creating a discontinuous flow of secondary fibers. This can be achieved by providing a burst of secondary fiber material from an ejector, rather than a continuous flow. This will have the effect of creating short segments of secondary fibers that span the primary fibers, with the free endpoints on the other side of the intersection, similar to the secondary structure of natural down shown in Figure 1B. Alternatively or additionally, when the secondary fiber material is positioned on the primary fiber structure, a directed stream of air or gas can be used to interrupt the continuous flow or create bends in the segments of the secondary fiber material.

In a given system, the diameter and/or shape or size of the outlet port of the ejector can be uniform or they can vary. In some embodiments, the outlet port is formed as a nozzle of predetermined length with a taper that decreases toward the port. The outlet port and associated passages or channels for the ejector can be formed using known micro-milling techniques, or techniques yet to be discovered. Known techniques include mechanical grinding, chemical etching, and laser drilling and ablation.

In addition to ultrafine fibers, the forcespinning system according to the present inventive subject matter can be used to produce fibers of standard textile sizes (eg, 50-150 denier).

The fibers of any embodiment may include functional particles such as, but not limited to, antimicrobial agents, metals, flame retardants, antistatic agents, water repellents, and ceramics. These materials may be incorporated into the fiber-forming material. They may be covalently bonded to the material through, for example, hydrogen bonds, ionic bonds, or van der Waals forces. A catalyst may be included in the material mixture to facilitate any such bonding.

In certain embodiments of the present subject matter, the flowable fiber-forming material can be a mixture of two or more polymers and/or two or more copolymers. In other embodiments, the fiber-forming material polymer can be a mixture of one or more polymers and/or one or more copolymers. In other embodiments, the fiber-forming material can be a mixture of one or more synthetic polymers and one or more naturally occurring polymers.

In some embodiments according to the present inventive subject matter, the fiber-forming material is supplied to the reservoir as a polymer solution, i.e., a polymer dissolved in a suitable solvent. In this embodiment, the method may further comprise dissolving the polymer in a solvent before supplying the polymer to the reservoir. In other embodiments, the polymer is supplied to the reservoir as a polymer melt. In such embodiments, the reservoir is heated at a temperature suitable for melting the polymer, for example, at a temperature of about 100° C. to about 300° C.

In some embodiments according to the present inventive subject matter, a plurality of micron, submicron, or nanometer-sized polymer fibers are formed. The plurality of micron, submicron, or nanometer-sized polymer fibers can have the same diameter or different diameters.

In some embodiments according to the present subject matter, the methods of the present invention result in the manufacture of micron, submicron, or nanometer sized particles. For example, it is contemplated that particles having a size of about 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560 , 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1000, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1000, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1000, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1000, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1000, 200 Sizes and ranges between the recited diameters are also part of the subject matter of the present invention.

The polymer fiber formed using the method and apparatus of the present invention can have a length range based on an aspect ratio equal to or greater than 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 500, 1000, 5000 or higher relative to the aforementioned fiber diameter. In one embodiment, the length of the polymer fiber depends at least in part on the time length of the device rotation or oscillation and/or the amount of the polymer supplied to the system. For example, it is considered that the polymer fiber can be formed as having a length of at least 0.5 micron before or after segmentation, including a length in the range of about 0.5 micron to 10 meters or larger. In addition, any suitable instrument can be used to cut the polymer fiber into the desired length. Size and scope between the lengths described are also a part of the subject matter of the present invention.

A variety of materials (synthetic, natural, based on biological plants, based on biological fermentation) and fabric/substrate types (knitted fabrics, woven fabrics and non-woven fabrics) are envisioned for use in the final product. Non-limiting examples of ultrafine fibers that can be produced using the methods and apparatus discussed herein include natural and synthetic polymers, polymer blends and other fiber-forming materials. Polymers and other fiber-forming materials can include biomaterials (e.g., biodegradable and bioabsorbable materials, plant-based biopolymers, based on biological fermentation polymers), metals, metal alloys, ceramics, composites and carbon ultrafine fibers. Non-limiting examples of specific ultrafine fibers prepared using the methods and apparatus discussed herein include polytetrafluoroethylene (PTFE), polypropylene (PP), polyurethane (PU), nylon, bismuth and β-lactam ultrafine fibers.

As noted above, the microfiber collection can include a blend of multiple materials. The microfibers can also include a single or multiple cavities. They can also have surface features, such as concave surfaces or holes. Multi-cavity microfibers can be achieved by designing one or more outlet ports with concentric openings, for example. In certain embodiments, such openings can include split openings (i.e., openings with one or more separators to enable two or more smaller openings). These features can be used to obtain specific physical properties. For example, the fiber can be manufactured to be used as a thermal insulation material, such as in the thermal insulation applications described below, or as an elastic (rebound) force or inelastic force attenuator.

In certain embodiments, the fibrous webs of the present disclosure may include elastic fibers, such as polyurethane and polyacrylate based polymers, to impart stretchability to nonwoven textiles made according to the present subject matter.

Compared to the prior art, ultrafine fibers according to the stream extrusion teachings herein can be used to achieve improved properties based on the ultrafine fiber diameter and/or the use of nanotubes or other structures that increase the volume of trapped air per given density unit of the insulation material. The ultrafine fibers can be blended with larger diameter fibers that provide strength or durability to the blended fiber construction.

The fibers in the construction of the insulating material can have substantially the same denier, or they can be a mixture of deniers. In either case, a suitable range for many applications is about 1-6 denier. In clothing applications, a suitable range can be about 1-3 denier.

In any of the foregoing embodiments, a flow of directionally controlled or pulsed air or other gas can be used to help pull the secondary fibers and arrange them on the primary fibers. Heating of the flow can facilitate the pulling and bonding process. One or more outlets for the gas can be positioned at a desired location adjacent to the outlet for the fiber-forming material. The gas outlet can also be in the form of a full or partial ring surrounding the outlet for the flowable material.

The composite structure of the extruded or sprayed or stretched filamentary material produced by any method contemplated herein can be cut, interrupted, cut and otherwise divided into desired fiber lengths. The fiber can be divided by any other known or yet to be discovered segmentation method of mechanical cutting devices, laser energy, thermal energy, ultrasonic energy and physical structure. The example of mechanical cutting includes a simple cutter or rotary cutting blade, which is known in the industry for producing short-length cut staple fibers. Suitable lengths can be about 0.1mm-5cm, as well as other lengths contemplated elsewhere herein. Suitable lengths for simulating the main structure of natural down are about 5mm-70mm, or about 3mm-33mm, or about 14mm-20mm, as shown elsewhere. If the segments are too small, the fibers may not be fluffy. If they are too long, they may permanently tangle.

Just as the secondary fibers can be arranged in a spaced relationship along any primary fiber, the tertiary fibers can be arranged in a spaced relationship along any secondary fiber. For example, the principles disclosed above for producing secondary fibers on primary fibers can be applied to a filamentous composite material that first produces secondary fibers and tertiary fibers in the same or different relative size ratios as the primary and secondary fibers. For example, the dimensions of the tertiary structure can mimic the dimensions of natural down. The filamentous material can be collected and flowed in a softened or solid phase on the primary structure using the techniques disclosed and contemplated herein. The tertiary fibers can be made using the same materials as used for the primary or secondary fibers.

The initial composite structure formed by fibers 112 and 114 can have an indefinite length based on the main fibers formed in the continuous processing operation. The length can range from a few microns to hundreds of meters or more. The loops 16 can have extreme points extending from the main structure of approximately 100μm-1000μm. A length of approximately 300μm-1000μm can simulate the natural down length of approximately 600μm-700μm. If the loops are too short, they may not allow for good separation of the main fibers. If the loops are too long, they may tangle. The intersections of the secondary fibers with the main fibers can have a spacing between 10μm-150μm. A spacing of approximately 40μm-80μm can simulate the approximately 60μm spacing of natural down.

(All measurements assume that the corresponding dimension is measured by following the path of the applicable structure. For example, if the main structure has a curved path, the length is not measured in a straight line from one end point to the other, but is measured by following the curved structure. Of course, the length is also the same distance that would be measured if the curved structure were straightened).

One of many possible embodiments is described below, but it relates to a unit of synthetic down that is intended to closely simulate some or all of the characteristics of natural down. As pointed out, the secondary fibers do not need to be neatly arranged on the main fibers. A noteworthy parameter is the length ratio of the main fibers to the secondary fibers. This ratio should preferably be about 20: 1, and in any case be between about 4: 1 and about 100: 1. A possible embodiment closely simulates several natural down properties, with a main fiber of about 20 μm-30 μm diameter; a secondary fiber diameter of about 1 μm-20 μm and a main fiber to secondary fiber length ratio of about 20: 1. The average spacing of the secondary fibers on the main fibers is about 60 μm (however, this will vary due to random fiber variations in the meltblown process or other production processes). A notable feature is that the secondary fibers are arranged transversely to the main fibers. In some embodiments, the secondary fibers can be arranged substantially perpendicular to the main fibers (in contrast to conventional yarns in which the fibers are substantially parallel to the yarn, have a small offset and are twisted). In another possible embodiment, secondary fibers can be wrapped directly around the primary fibers after extrusion and before placement due to the nature of force spinning.

In one possible embodiment, the spinneret can have multiple orifices, each of which can have a different diameter to produce a variety of nanofibers and micron-sized fibers on the same spinneret. The orifices can be arranged in or out of the same plane to facilitate winding of different smaller fibers around the larger fiber during spinneret rotation. The overall composite structure of the primary fiber and secondary fiber units should have a low density equal to or less than about 1% of the fill volume.

Polyester filament is the exemplary starting material for preparing the filling material structure disclosed or envisioned herein, particularly for simulating those structures of natural down. Other synthetic materials or natural materials for one or both of the primary and secondary structures include: polyester (ethylene terephthalate), polyolefins (polypropylene and polyethylene or their copolymers). Material can also be any other synthetic fiber currently used in meltblown method (or electrospinning, if using electrospinning process). Example includes: other polyesters, such as poly (trimethylene terephthalate) (Sorona ^™ ), polyamide (for example, nylon), poly (methyl methacrylate) (acrylic acid), poly (acrylonitrile), ethylene acrylic copolymer, polystyrene, polytetrafluoroethylene (PTFE), ethylene chlorotrifluoroethylene (ECTFE), polyurethane, polycarbonate, asphalt and above-mentioned two or more blends. As noted above, primary fiber and secondary fiber can be made of different materials, but polyester is an example of suitable material for both.

For some thermal insulation applications, factors influencing fiber selection may include:

Young's modulus - should be much higher than ~10MPa

Yield strain - should be as high as possible, at least 1%, and preferably greater than 10%

The coefficient of friction should ideally be anisotropic in that when the insulation is compressed the friction should be high and when allowed to re-loft the friction should be low (down achieves this using its tertiary structure)

Hydrophobic fibers are highly preferred to make the insulation material resistant to moisture

In addition to being surface-hydrophobic, the fiber should generally be resistant to moisture and its mechanical properties should not change when wet

Low bulk density, equal to or less than about 30 kg/m ³ once the yarn is packed into the compartment. Natural down is about 10 kg/m ³ once packed into the compartment. Heavier insulation materials of about 20-30 kg/m ³ are a specific range within the scope of this invention. (The bulk density of unpacked yarn alone may not be a meaningful number, as they can be planar in structure and, when packed into the compartment, can interpenetrate to some extent, with a sufficiently low bulk density so that the fiber units can avoid tangling with themselves).

The porosity of natural goose down is an indicator of two important characteristics: warmth-to-weight ratio and compressibility, both of which are crucial for warmth and comfort. True porosity is measured by placing one ounce of goose down in a graduated cylinder and measuring the volume in cubic inches occupied by the down. It is believed that insulating materials made according to embodiments of the present inventive subject matter can rival goose down and provide a porosity of approximately 550-900, similar to that of goose down.

The present subject matter is particularly directed to certain articles of manufacture that include insulating units. Articles of manufacture include any range of articles in which such insulating materials may be used in the following items, including clothing and apparel, such as insulated jackets and pants; footwear, such as shoes and socks; headwear, such as car coats and other insulated hats, and face masks; outdoor equipment, such as sleeping bags and shells for sleeping bags, blankets, tents, tarps and other coverings; bedding, pillows, pads, cushions, and the like. Typically, such products are composed of a predetermined amount of fill material enclosed within a woven or non-woven or knitted textile or fabric in the form of a sealed compartment having a plurality of walls that are sealed by sewing, knitting, weaving, bonding, gluing, fusion bonding, or other known or yet to be discovered means of sealing the textile or fabric material. Figure 16 shows a representative product, namely a coat 36 having a plurality of compartments 38 throughout the body, with the ends and hood portion filled with an insulating construct according to the present subject matter. The garment can have a compartment with an outward-facing wall and an inner wall (facing the body), the outward-facing wall being a durable material, for example, tear-resistant (e.g., Cordura ^™ ) nylon, and the inner wall being a finer or more comfortable material, for example, polyester, wool, cotton, or merino wool. Another layer can be laminated to the outer layer and/or inner layer. For example, a waterproof, breathable membrane material, such as a barrier layer of expanded PTFE (e.g., Gore-Tex brand PTFE) can be laminated to the inner layer or outer layer. Other possible layers include a hydrophilic layer or other functional layer that wicks moisture. Any wall or layer can also be made of an elastic material, such as spandex or polyurethane yarn.

Those skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of components and functions that have been described and illustrated to explain the nature of the inventive subject matter, and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.

All patent and non-patent literature cited herein are hereby incorporated by reference in their entirety for all purposes.

As used herein, "and/or" means "and" or "or," as well as "and" and "or." Furthermore, any and all patent and non-patent documents cited herein are hereby incorporated by reference in their entirety for all purposes.

The principles described above in conjunction with any specific example can be combined with the principles described in conjunction with any one or more other examples. Therefore, this detailed description should not be interpreted in a limiting sense, and after reviewing this disclosure, one of ordinary skill in the art will understand that a wide variety of provided systems and other systems can be designed using the various concepts described herein. In addition, one of ordinary skill in the art will understand that the exemplary embodiments disclosed herein can be applied to a variety of configurations without departing from the principles disclosed.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the disclosed innovations. Various modifications to those embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the claimed invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically stated otherwise, but rather "one or more."

All structural and functional equivalents to the elements of the various embodiments described throughout this disclosure that are known or later become known to those of ordinary skill in the art are intended to be encompassed by the features described and claimed herein. In addition, nothing that is not disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. Unless the phrase "means for..." or "step for..." is used to expressly recite the element, an element of a claim should not be construed as a "means-plus-function" claim under U.S. patent law.

Claims (21)

1. A volumetric filling material comprising a plurality of fiber structures having sufficient bulk and resilience to be suitable for padding and/or insulation applications, each structure comprising: Main fibers of predetermined length; and A secondary fiber structure comprising multiple loops, each loop consisting of a single monofilament fiber and having a pair of spaced-apart intersections with the main fiber, wherein each of the intersections between the main fiber and the single monofilament fiber is spaced apart along the length of the main fiber from other intersections between the main fiber and the single monofilament fiber, and the main fiber and the secondary fiber structure are joined together at the intersections by a material bonding process. The main fiber has a length of 0.1 mm to 5 cm. 2. The volumetric filling material according to claim 1, wherein the length of the main fiber is between 5 mm and 70 mm. 3. The volumetric filling material according to claim 1, wherein the secondary fiber structure has more than 20 rings. 4. The volumetric filling material according to claim 3, wherein the intersection point of the secondary fiber structure and the main fiber is 10μm-150μm apart. 5. The volumetric filling material according to claim 1, 3 or 4, wherein the ring of the secondary fiber structure has an extreme point of 5 mm or less. 6. The volumetric filling material according to claim 1, 3 or 4, wherein the rings of the secondary fiber structure have extreme points between 100 μm and 1 mm. 7. The volumetric filling material according to claim 3 or 4, wherein the rings of the secondary fiber structure have extreme points between 300 μm and 1000 μm. 8. The volumetric filling material according to claim 1, wherein the main fiber has a diameter equal to or less than 100 μm. 9. The volumetric filling material according to claim 1, 3 or 4, wherein one or both of the primary fiber and the secondary fiber structure comprises a thermoplastic material, the thermoplastic material of one or both of the primary fiber and the secondary fiber structure is fused to the material of the primary fiber and/or the other of the secondary fiber structure to provide a bonding of materials, the primary fiber and the secondary fiber structure being in the form of a given fiber construct forming an integral structure. 10. The volumetric filling material according to claim 1, wherein the primary fiber and/or the secondary fiber structure comprises hollow fibers. 11. The volumetric filling material of claim 1, wherein the rings of the secondary fiber structure are in a mode comprising a generally sinusoidal pattern, and the primary fiber comprises a baseline for the sinusoidal pattern. 12. The volumetric filling material of claim 3, wherein the rings of the secondary fiber structure are arranged in a plurality of planes in a configuration that is twisted or spiraled around the primary fiber. 13. The volumetric filling material according to claim 1 or 3, wherein the ring of the secondary fiber structure comprises a continuous line of secondary material fused with the primary fiber to form an integral structure, wherein the primary fiber has higher stiffness, tensile strength and/or higher thickness relative to the secondary fiber structure. 14. The volumetric filling material of claim 1, wherein the rings of the given secondary fiber structure are arranged in a plurality of planes with the main fiber. 15. The volumetric filling material of claim 6, wherein one or both of the primary fiber and the secondary fiber structure comprises a thermoplastic material, the thermoplastic material of one or both of the primary fiber and the secondary fiber structure being fused to the material of the primary fiber and/or the other of the secondary fiber structure to provide a bonding of materials, the primary fiber and the secondary fiber structure being in the form of a given fiber construct forming an integral structure. 16. A volumetric filling material comprising a plurality of fibrous structures according to claim 1, wherein the plurality of such structures have a volumetric density of about 50 kg/ ^m³ or less. 17. A method for manufacturing a fibrous structure, comprising: A stream of molten or softened fiber-forming material for primary or secondary fibers is ejected from a first ejector onto a stream or structure for another of the primary or secondary fibers in a predetermined pattern to produce a composite fiber structure of primary and secondary fibers, wherein, in the predetermined pattern, the secondary fibers are arranged in multiple rings on the primary fiber; and The length of the main fiber is divided into multiple smaller structural units, wherein the average length of the divided main fiber is between 0.1 mm and 5 cm. 18. The method of claim 17, wherein, on average, each of the segmented master fibers has more than 20 loops. 19. The method of claim 17, wherein the flow of the material is sprayed using a system comprising a melt-blowing, electrospinning, or force-spinning system for melting or thermally softening materials. 20. The method of claim 17, wherein the material of the secondary fiber is compressed and shaped onto the material of the primary fiber. 21. A volumetric filler material comprising a plurality of fiber structures having a bulk density of about 50 kg/ ^m³ or less, wherein a sufficient number of such structures provide a porosity of 550-1000, and Each fiber structure includes: Main fibers, which comprise fibers of a predetermined length; and A secondary fiber structure comprising multiple loops, each loop consisting of a single monofilament fiber and having a pair of spaced-apart intersections with the main fiber, wherein each intersection of the main fiber and the single monofilament fiber is spaced apart along the length of the main fiber from other intersections of the main fiber and the single monofilament fiber, and the main fiber and the secondary fiber structure are joined together at the intersections by a material bonding process. The secondary fiber structure has more than 20 rings. The main fiber has a length of 0.1 mm to 5 cm, and The secondary fiber structure is spaced 10μm-150μm from the intersection point of the primary fiber, and The rings of the secondary fiber structure have extreme points between 100 μm and 1 mm.