SPACER FABRICS AND METHODS OF MAKING THE SAME
In one aspect, methods of making a spacer fabric are described herein. In some embodiments, a method comprises knitting a first yarn or fiber and a second yarn or fiber to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions. Further, the concave portions and the convex portions together define void spaces having a substantially double convex cross section. In some cases, the method further comprises heating the knit structure at a temperature sufficient to cause the second yarn or fiber to shrink in at least one dimension. Additionally, the second yarn or fiber shrinks more than the first yarn or fiber during the heating step. Moreover, in some instances, heating the knit structure increases a size of the void spaces of the knit structure, particularly in a thickness direction of the fabric.
This application claims priority pursuant to 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. No. 62/453,147, filed Feb. 1, 2017, which is hereby incorporated by reference in its entirety
FIELDThis invention relates to spacer fabrics and, in particular, to knitted spacer fabrics and methods of making the same.
BACKGROUNDSpacer fabrics have been used as components of various products, ranging from footwear to costumes to backpacks. In conventional spacer fabrics, two separate fabrics (which may be referred to as a top fabric and a bottom fabric) are joined by fibers or filaments in a “sandwich” like construction, in which the top fabric and bottom fabric are spaced apart from one another by the intervening fibers or filaments. The intervening fibers or filaments typically have a low density, such that the region or space between the top fabric and the bottom fabric consists largely of air or empty space. However, some prior spacer fabric constructions provide a limited resistance to compression and/or provide only a single compressive resistance throughout the fabric. Some spacer fabrics can also require expensive, complicated, or time-consuming manufacturing process. Therefore, there exists a need for improved spacer fabrics and improved methods of making spacer fabrics, including for applications requiring an increased compressive resistance and/or a varying compressive resistance.
SUMMARYSpacer fabrics and methods of making the same are described herein. Such fabrics can provide one or more advantages compared to other fabrics. For example, in some instances, the spacer fabrics described herein provide improved compression resistance, strength, durability, and/or cushioning. Spacer fabrics described herein can also provide non-uniform or varying properties across one or more lateral dimensions of the fabric. For instance, in some embodiments, a spacer fabric described herein comprises a plurality of zones of differing compression resistances. Such zones can correspond to a pressure map of the spacer fabric during use in an end application, such as a seating application or a footwear application. Moreover, in certain cases, spacer fabrics described herein incorporate electrically and/or thermally conductive fibers, yarns, or filaments for providing fabrics that can be heated or cooled, perform diagnostics, and/or massage portions of a user's body during use. Additionally, methods described herein can provide or form a spacer fabric in a more efficient and/or cost-effective manner compared to some other methods.
In one aspect, a method of making a spacer fabric is provided. Such a method, in some cases, comprises knitting a first yarn, filament, or fiber and a second yarn, filament or fiber to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions. The concave portions and the convex portions define void spaces having a substantially double convex cross section. Further, the first yarn, filament, or fiber is a low thermal shrinkage yarn, filament, or fiber, and the second yarn is a high thermal shrinkage yarn, filament, or fiber, where “low” and “high” are understood to be relative terms, as described further hereinbelow. The method further comprises heating the knit structure at a temperature sufficient to cause the second yarn (or filament or fiber) to shrink by at least 10% in at least one dimension. Moreover, the second yarn (or filament or fiber) shrinks more than the first yarn (or filament or fiber) in the at least one dimension during the step of heating the knit structure. In some embodiments, the second yarn (or filament or fiber) shrinks by 10-90% in the at least one dimension during the step of heating the knit structure, based on an original size of the second yarn (or filament or fiber) in the at least one dimension prior to the step of heating the knit structure. Further, in some cases, the second yarn (or filament or fiber) shrinks at least two times as much as the first yarn (or filament or fiber) in the at least one dimension during the step of heating the knit structure.
Moreover, the step of heating the knit structure can increase a size of the void spaces in a thickness direction of the fabric. For example, in some embodiments, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 100%.
A method described herein can further comprise forming a knit structure from one or more additional yarns, in addition to the first yarn and the second yarn. Generally, “n” additional yarns may be used to form a knit structure described herein, wherein n is not particularly limited (e.g., n can be equal to 1, 2, 3, 4, or 5, or n can be equal to any integer between 1 and 100). In some cases, for example, a method described herein further comprises forming a knit structure from a third (or nth) yarn in addition to the first yarn and the second yarn (or in addition to the previously recited (n−1) yarns). The third yarn (or nth yarn) can differ from the first yarn and the second yarn (or from one or more of the (n−1) previously recited yarns). For example, in some cases, the third yarn (or nth yarn) is a thermally fusible yarn. The third yarn (or nth yarn) can be fusible at the temperature of the step of heating the knit structure. Similarly, a method described herein can further comprise forming a knit structure from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn. The fourth yarn can differ from the first yarn, the second yarn, and the third yarn. For example, the fourth yarn can have a color, texture, denier, and/or elasticity that differs from the color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn. It is again to be understood that methods described herein are not limited to the use of 3 or 4 differing yarns. Instead, n yarns or yarn types may generally be used, and the n yarns or yarn types may be the same or different from one another in a variety of ways, including those described above.
Moreover, a spacer fabric described herein, after heating, can comprise a plurality of zones having differing properties. For instance, in some cases, the spacer fabric, after heating, has or exhibits different compression resistances in a thickness direction of the fabric (where the thickness direction may be denoted as the z-direction). In such instances, it is to be understood that the compression resistance of the fabric varies as a function of one or both lateral dimensions of the fabric (where the lateral dimensions or directions of the fabric may be denoted as the x-direction and the y-direction). Moreover, a spacer fabric formed by a method described herein can have one or more first zones of low compression resistance and one or more second zones of high compression resistance, where the terms “low” and “high” are understood to be relative to one another. For example, the first zones, in some embodiments, have a compression resistance of no more than 30 psi, and the second zones have a compression resistance of at least 50 psi. Additionally, in some instances, the locations of the first and second zones can be determined based on a pressure map of the fabric when in use in an end application. For example, the end application can be a seating application, a footwear application, or any other application not inconsistent with the objectives of the present disclosure.
Methods described herein can be carried out in any manner not inconsistent with the objectives of the present disclosure, as described further hereinbelow.
In a further aspect, spacer fabrics are described herein. In some embodiments, a spacer fabric described herein comprises a knit structure formed from a first yarn and a second yarn, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces. The void spaces can have double convex or substantially double convex cross sections. Moreover, the first yarn can comprise a low thermal shrinkage yarn and the second yarn can comprise a high thermal shrinkage yarn. Again, the terms “low” and “high” are to be understood to be relative to one another. In some cases, for example, the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C. Further, in some embodiments, heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension will increase a size of the void spaces in a thickness direction of the fabric.
Moreover, in some cases, a spacer fabric described herein, when unheated, is flat or substantially flat. Additionally, in some embodiments, a thickness of the fabric (e.g., in the z-direction) increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.
As described above, knit structures described herein can be formed from one or more yarns in addition to the first and second yarns. Up to “n” additional yarns may be included in a knit structure descried herein. For example, in some embodiments, a knit structure is formed from a third yarn in addition to the first yarn and the second yarn, and the third yarn differs from the first yarn and/or the second yarn. In some cases, the third yarn comprises a thermally fusible yarn. Moreover, in some such instances, the third yarn may be fusible at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension. Similarly, in some cases, a knit structure of a fabric described herein may be formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn. Such a fourth yarn can differ the first yarn, the second yarn, and/or the third yarn. For example, the fourth yarn can have a color, texture, denier, and/or elasticity that differs from the color, texture, denier, and/or elasticity of any of the first yarn, the second, yarn, and/or the third yarn.
Additionally, the knit structure of a fabric described herein, in certain embodiments, is a unitary knit structure. Moreover, in some embodiments, a fabric described herein comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. For instance, the fabric can comprise one or more first zones of low compression resistance and one or more second zones of high compression resistance. In some such cases, the first zones can have a compression resistance of no more than 30 psi and the second zones can have a compression resistance of at least 50 psi. Further, the locations of the first and second zones can correspond to a pressure map of the fabric when in use in an end application. For example, in some cases the fabric forms a portion of a seat or seat back. Alternatively, the fabric can form a portion of footwear.
These and other embodiments are described in greater detail in the detailed description which follows.
Embodiments described herein can be understood more readily by reference to the following detailed description, examples, and figures. Elements, apparatus, and methods described herein, however, are not limited to the specific embodiments presented in the detailed description, examples, and figures. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the scope of the invention.
In addition, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1.0 to 10.0” should be considered to include any and all subranges beginning with a minimum value of 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.
All ranges disclosed herein are also to be considered to include the end points of the range, unless expressly stated otherwise. For example, a range of “between 5 and 10,” “from 5 to 10” or “5-10” should generally be considered to include the end points 5 and 10.
I. Methods of Making a Spacer FabricIn one aspect, methods of making a spacer fabric are described herein which, in some cases, can provide one or more advantages compared to other methods. For example, in some instances, a method described herein can provide a spacer fabric that has improved compression resistance. A method described herein can also be used to make a spacer fabric having a plurality of zones of differing compression resistances. Moreover, the zones can correspond to a pressure map of the spacer fabric during use in an end application, such as a seating application or a footwear application. Further, a method described herein can provide a spacer fabric in a more efficient and/or cost-effective manner compared to some other methods.
A method of making a spacer fabric described herein, in some embodiments, comprises knitting a first yarn (or fiber) and a second yarn (or fiber) to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions. The concave portions can be repeating portions, such that they form a wave-like or sinusoidal shape in a length or width direction of the knit structure. Similarly, the convex portions can be repeating portions, such that they form a wave-like or sinusoidal shape in a length or width direction of the knit structure, as described further below. Further, the concave portions and the convex portions together define void spaces having a substantially double convex cross section. More particularly, the concave portions and the convex portions can be aligned with one another, including in a one-to-one manner, such as may be caused by an off-set in the sinusoidal shape or pattern formed by the plurality of concave portions and the sinusoidal shape or pattern formed by the plurality of convex portions. For instance, in some cases, each concave portion is mirrored by or aligned with a corresponding convex portion in facing opposition to the concave portion, thereby defining a double convex void space. It is to be understood that a “double convex” cross section or shape is a shape defined by two convex curves in a back to back configuration, such as in a double convex lens, as opposed to the configuration of a plano-convex lens or a concavo-convex lens. A “substantially” double convex cross section or shape refers to a cross section or shape that is essentially a double convex cross section or shape, but that may differ from such a shape by a de minimis amount, such as by having an “offset” from a back to back configuration of less than 5%, less than 3%, or less than 1%. Moreover, the knit structure of a spacer fabric described herein can be a unitary knit structure, as opposed to a knit structure formed by sewing, linking, or otherwise joining separate fabrics in a non-knitting manner.
Additionally, the first yarn (or fiber) used to form the knit structure is a low thermal shrinkage yarn (or fiber), and the second yarn (or fiber) is a high thermal shrinkage yarn (or fiber). It is to be understood that the terms “low” and “high” thermal shrinkage are relative to one another. In other words, the “low” thermal shrinkage yarn shrinks less in response to heating than the “high” thermal shrinkage yarn does. In some embodiments, the “high” thermal shrinkage yarn (or fiber) shrinks at least twice as much, at least three times as much, at least five times as much, or at least 10 times as much as the “low” thermal shrinkage yarn (or fiber) at a given temperature or other heating condition, in at least one dimension, where the amount of shrinkage of each yarn (or fiber) is a percent shrinkage based on the original dimension of the respective yarn (or fiber) at 25° C., prior to heating. In some instances, the high thermal shrinkage yarn (or fiber) shrinks 2-100 times, 2-50 times, 2-20 times, 2-10 times, 2-5 times, 2-4 times, 5-100 times, 5-50 times, 5-20 times, 5-10 times, 10-100 times, 10-50 times, or 10-20 times as much in at least one dimension as the low thermal shrinkage yarn (or fiber) does at a given temperature or other heating condition. Moreover, in some preferred embodiments, the dimension of thermal shrinkage is a longitudinal or “length” direction of the yarn (or fiber), as opposed to a radial or “width” dimension of the yarn (or fiber). Alternatively, in some cases, thermal shrinkage (including differential thermal shrinkage as compared between the two yarns or fibers) occurs in a radial direction of a yarn (or fiber). In still other instances, the differential thermal shrinkage occurs in a radial direction as well as a longitudinal direction of the yarns (or fibers).
Turning again to steps of methods described herein, methods described herein, in some embodiments, further comprise heating the knit structure at a temperature sufficient to cause the second yarn or fiber to shrink in at least one dimension. In some cases, the second yarn or fiber shrinks by at least 10% in at least one dimension, where the percentage is based on an original size or length of the second yarn or fiber in the at least one dimension prior to the step of heating the knit structure. In some cases, the second yarn or fiber shrinks by at least 20%, at least 30%, or at least 40% in at least one dimension. In some embodiments, the second yarn or fiber shrinks by 10-90% in the at least one dimension during the step of heating the knit structure. Additionally, it is to be understood that the second yarn or fiber shrinks more than the first yarn or fiber in the at least one dimension during the step of heating the knit structure. For example, in some cases, the first yarn or fiber shrinks by less than 10%, less than 8%, less than 5%, or less than 3% in the at least one dimension during the heating step, based on an original size or length of the first yarn or fiber in the at least one dimension prior to the step of heating the knit structure.
Further, in general, the step of heating the knit structure increases a size of the void spaces of the knit structure, particularly in a thickness direction or z-direction of the fabric. A “thickness” direction of the fabric, for reference purposes herein, is orthogonal to the width and length directions (or x- and y-directions) of the fabric. Often, the “thickness” or z-direction is the shortest dimension of the fabric, which may have much larger width (x-) and length (y-) directions. It is further to be understood that the z-direction of the fabric can be generally orthogonal to the “direction of propagation” or “crest-to-crest direction” of the sinusoidal shapes or patterns formed by the plurality of concave portions and the plurality of convex portions. In some embodiments, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 100%. In some cases, the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 200%, at least 300%, at least 400%, at least 500%, at least 700%, at least 900%, or at least 1000%. In some instances, the size of the void spaces in the thickness direction of the fabric increases by 100-5000%, 100-1000%, 100-900%, 100-500%, 100-300%, 200-5000%, 200-1000%, 300-5000%, or 300-1000%. Additionally, in some embodiments, the fabric is flat or substantially flat prior to heating, and raised or non-flat or “three-dimensional” after heating. In some instances, the thickness of the fabric increases by at least 0.5 cm, at least 1 cm, at least 2 cm, at least 3 cm, or at least 5 cm after heating. Other increases in thickness are also possible. A “substantially” flat fabric, for reference purposes herein, can be within 10%, within 5%, within 3%, or within 1% of being flat under standard temperature and pressure conditions (in particular IUPAC STP conditions), the percentage being based on an increase in thickness of the “substantially” flat fabric, as compared to an otherwise identical fabric that is “flat” under the standard temperature and pressure conditions.
Any yarns or fibers not inconsistent with the objectives of the present disclosure may be used to form the knit structure of a spacer fabric described herein. Further, it is to be understood that “yarns” or “fibers” as used hereinabove can refer collectively to fibers, yarns, and filaments. In some cases, for instance, a knit structure is formed from a single component yarn, a multi-component yarn (such as a bi-component yarn or a yarn having 3 components (i.e., a tri-component yarn), a yarn having 4 components (i.e., a quad-component yarn), or a yarn having more than 4 components), or a combination thereof. A multi-component yarn can have a sheath/core structure, a side-by-side structure, or an islands-in-the-sea structure. Other multi-component yarn structures can also be used.
Further, in some embodiments, a knit structure is formed from a mono-component monofilament yarn, a multi-component monofilament yarn, a mono-component multifilament yarn, a multi-component multifilament yarn, or a combination thereof. A yarn used in a method described herein may also include separate filaments formed from different materials, or a plurality of filaments that are each formed from two or more different materials. It is also to be understood that a “yarn” such as a “first yarn” or a “second yarn” described herein can refer to a type of yarn, as opposed to simply a single yarn. Thus, for instance, use of “a first yarn” and “a second yarn” to provide a knit structure in a manner described herein is to be understood to refer to the use of one or more yarns of a first type (corresponding to “a first yarn”) and one or more yarns of a second type (corresponding to “a second yarn”).
In some preferred embodiments, the first yarn is a monofilament yarn. In some such instances, for example, the first yarn is a monocomponent monofilament yarn or a multi-component monofilament yarn. In addition, in some cases, the first yarn has a higher stiffness or modulus than the second yarn. Additionally, in some embodiments, the second yarn is a multifilament yarn. For example, in some instances, the second yarn is a monocomponent multifilament yarn or a multi-component multifilament yarn.
Moreover, in some cases, a knit structure described herein is formed from a third yarn in addition to the first yarn and the second yarn, the third yarn differing from the first yarn and the second yarn. Any third yarn not inconsistent with the objectives of the present disclosure can be used. For example, in some embodiments, the third yarn is a thermally fusible or heat-fusible yarn. In some cases, such a third yarn is fusible at the temperature of the step of heating the knit structure. Additionally, in some such instances, stable and elastic single component multifilament and/or monofilament yarns are used as the third yarns. In some cases, the yarns can be formed from low melting point polymers, such as polymers having a melting point below about 200° C., 150° C., below about 100° C., or below about 80° C. In some embodiments, the yarns can be formed from polymers having a melting point between about 80° C. and about 150° C. Such yarns can be heated, with or without pressure, to cause the low melting components to melt and flow, thereby modifying the physical properties of the knit structure, including by serving as an adhesive. In other cases, stable and elastic multi-component (e.g., bi-component) multifilament and/or monofilament yarns are used. In some such embodiments, the yarns can be formed from low melting polymers in combination with higher melting point polymers (such as polyester or nylon), such that the low melting polymer components but not the higher melting components of the yarns can be made to melt and flow by the application of heat with or without pressure, thereby modifying the physical properties of the knit structure in a desired manner, including by providing an adhesive element and/or structural support.
Further, in some embodiments, a knit structure described herein is formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn, wherein the fourth yarn differs from the first yarn, the second yarn, and the third yarn. Any fourth yarn not inconsistent with the objectives of the present invention can be used. Moreover, the fourth yarn can be used to provide desired performance features to a spacer fabric described herein, in addition to those described above. For instance, in some cases, the fourth yarn has a color, texture, denier, and/or elasticity that differs from a color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn.
As described above, a fiber, yarn, or filament or a portion of a fiber, yarn, or filament described here can comprise or be formed from any material not inconsistent with the objectives of the present invention. In some embodiments, for example, a fiber, yarn, or filament comprises or is formed from a synthetic material such as nylon or another polyamide, polyester, polyethylene, polypropylene, polybutylene, or another polyolefin, or polyacrylic. In other cases, a fiber, yarn, or filament comprises or is formed from a natural fiber material such as cotton, wool, or silk. Other fibers, yarns, and filament materials may also be used, such as regenerated cellulose or rayon. In certain cases, the fiber, yarn, or filament comprises or is formed from a rate-sensitive material, such as a rate-sensitive thermoplastic elastomer. Such materials are configured to exhibit different stiffness values at different frequencies or rates. For example, rate-sensitive materials can be soft, comfortable, and flexible at lower frequencies, but stiffen under higher frequencies for increasing the stability and performance. An exemplary rate-sensitive material is D30®, a DuPont™ Hytrel® thermoplastic elastomer.
In still other cases, the fiber, yarn, or filament comprises or is formed from a metallic material such as stainless steel, copper, or a metal mixture or metal alloy. In some instances, the metallic material is electrically conductive. Other electrically conductive fibers, yarns, or filaments may also be used. Such electrically conductive materials can be used, in some cases, for the dissipation of static charge and/or for the formation of “smart” or electrically integrated materials. For example, and in certain cases, formation of a smart material enables a spacer fabric constricted therefrom to provide diagnostics. Such diagnostics may include, for example, and without limitation, step-counting diagnostics, speed diagnostics, force or impact diagnostics, or any other type of diagnostic not inconsistent with objectives of the present invention. It is also possible for a fiber, yarn, or filament described herein to include or be formed from a shape memory material such as a shape memory polymer or a shape memory alloy. Other materials, such as pressure-chromic yarns may be used in the methods of forming the spacer fabrics described herein, for example, so that the spacer fabric is responsive or reactive to various changes or stimuli and, thus, varies in regards to the amount of stiffness or pressure provided by the fabric. Such fabrics may be used, for example, to massage the user's body (e.g., back, foot, etc.) when positioned adjacent or proximate to the spacer fabric.
A fiber, yarn, or filament described herein can also be coated with one or more additional materials to provide a desired property. In some cases, for instance, a fiber, yarn, or filament can be coated with a fluorocarbon such as polytetrafluoroethylene. A fiber, yarn, or filament described herein can also include one or more additives, including polymer additives, which can provide heat absorption and/or heat reflectivity properties, electrical conductivity and/or static dissipation properties, or low coefficient of friction properties. For example, such additives may be used to heat or cool the spacer fabric during use, such that the user's body (e.g., back, foot, etc.) may be heated or cooled during use via the spacer fabric. An additive can also be used to provide a “smart” fabric or textile. Non-limiting examples of thermally conductive additives which may be used in some embodiments described herein include ceramics such as aluminum nitride and/or boron nitride ceramics, metals such as aluminum or copper, and nanoscale carbon materials such as carbon fibers, carbon nanotubes, and graphite nanoplatelets.
Additives comprising thermochromic or photochromic pigment and dye materials may also be used. Such pigment and dye materials can change color in response to heat or light. It is also possible to incorporate one or more antimicrobial or antifungal materials into or onto a fiber, yarn, or filament described herein, including for odor control. Non-limiting examples of antimicrobial or antifungal materials that may be used in some embodiments described herein include inorganic, organic, and/or metal-containing antimicrobial materials such as materials comprising silver, copper, and/or zinc, and quaternary silane-based antimicrobial materials.
Moreover, a fiber, yarn, or filament described herein can have any size, shape, and/or denier not inconsistent with the objectives of the present invention.
In addition, a spacer fabric formed by a method described herein can comprise regions having the same or differing properties. For example, in some cases, a spacer fabric can have regions of the same or differing stability, rigidity, elasticity, support, softness, cover, durability against fraying, durability against unraveling, cushioning, compression, breathability, weight, density, color, water wicking ability, and/or water resistance. Further, the properties of a region of a spacer fabric described herein can be selected based on the type of knitting process, the type of stitch, and/or the chemical composition or type of fiber, yarn, or filament used to form the region. Thus, by selectively forming regions having differing properties, a spacer fabric can be provided that has both a unitary knitted structure and also complex features, varied regions, or features or regions selected for specific applications. The unitary structure can be formed by a single knitting operation according to a method described herein.
For example, a spacer fabric made by a method described herein can have one or more regions of high breathability (such as may be provided by the use of a meshed stitch structure), one or more regions of high elasticity (such as may be provided by the use of an elastomeric yarn), one or more regions of high rigidity (such as may be provided by the use of a non-elastomeric yarn), and/or one or more regions that can be further shaped using the heat treatment (such as may be provided by the use of a fusible yarn). In another instance, a spacer fabric made by a method described herein can include relatively soft regions and relatively abrasion resistant regions. A soft region may be located on one side (e.g., a user contacting side) of the spacer fabric, and an abrasion resistant region may be located on the other side (e.g., a non-user contacting side) of the spacer fabric. Selectively varying the type of knitting process, the type of stitch, and/or the chemical composition or type of fiber, yarn, or filament used during a method described herein can also provide spacer fabric having desired aesthetic, design, or texture elements.
In some preferred embodiments, a spacer fabric described herein, after heating, comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. For example, in some cases, the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance. It is to be understood that “low” and “high” compression resistance are relative to one another. For instance, in some embodiments, the first zones have a compression resistance of no more than 30 psi, no more than 20 psi, or no more than 10 psi, and the second zones have a compression resistance of at least 50 psi, at least 60 psi, at least 70 psi, at least 80 psi, or at least 100 psi. Moreover, in some cases, the locations of the first and second zones are determined based on a pressure map of the fabric when in use in an end application.
Spacer fabrics described herein can be used in any end application not inconsistent with the objectives of the present disclosure. Moreover, spacer fabrics described herein can be formed in a custom manner to meet the needs of a specific end use. Additionally, in general, a knit structure/spacer fabric described herein can have a definitive custom shape and dimension around the perimeter of the end product (e.g., the final fabric to be used in an end application) that is shaped on the knitting machine for the end use. In other words, the spacer fabric can be properly shaped for the end use without being cut or sewn. Thus, in some embodiments, a spacer fabric described herein is not cut or sewn, including for incorporation into a product or before incorporation into a product, such as a product described below.
In some cases, the end application of a spacer fabric described herein is a footwear application. A spacer fabric described herein, for example, can be used as a separate and removable insole of a shoe. A spacer fabric described herein may also be used to form a complete knit shoe upper with an integral spacer fabric sole/insole. In still other embodiments, a spacer fabric described herein can be used in footwear such as socks.
Additionally, the end application of a spacer fabric described herein can be an apparel application. For example, a spacer fabric described herein can be used in safety and sportswear components and garments, particularly components and garments in which cushioning regions may be desirable for impact resistance and protection in certain areas for force dampening from impact. As described above, spacer fabrics described herein can be configured to provide impact resistance in certain zones of the apparel, such as for use in high impact and dangerous sports such as football, cross country cycling and many others in which elbows, knees, hips, shins and skulls, and other bodily regions need cushioning from severe impact.
In other instances, the end application of a spacer fabric described herein is a seating application. For example, a spacer fabric can be used to form all or a portion of a chair back and/or seat for offices, homes, hospitals, wheel chairs, schools, automobiles, motorcycles, bicycles, lawn mowers, and other vehicles and devices. Further, such a seating component formed from a spacer fabric having differing zones, as described above, can help protect and support the body of a user from impact, including with reference to pressure mapping of the seating component when in use.
In still other embodiments, a spacer fabric described herein is used in bedding applications. For example, in some cases, a spacer fabric described herein can be used to provide a complete sleeping support surface, or to provide a component or element of a mattress. In some such instances, the spacer fabric can provide additional support and ventilation.
More generally, the three-dimensional structure of spacer fabrics described herein, which can include primarily void spaces/air as described above, without filaments extending between upper and lower surfaces, can facilitate or enable improved ventilation of the body of a user in contact with the spacer fabrics. Spacer fabrics described herein can also help maintain a user of the spacer fabrics at a desired temperature for the relevant end uses of the spacer fabrics.
Methods described herein can be carried out in any manner not inconsistent with the objectives of the present invention. For example, in some cases, a method described herein is carried out using a knitting machine. More particularly, in some embodiments, a method described herein is carried out using a weft knitting machine having at least two sets of needles. For example, in some instances, the knitting machine is a flat bed knitting machine having a front needle bed and a back needle bed. In other cases, the knitting machine is a circular knitting machine having a cylinder set of needles and a dial set of needles. In addition, a knitting machine used in a method described herein can be automated. For example, in some cases, a knitting machine is configured to carry out a knitting process according to needle-by-needle or stitch-by-stitch instructions provided by a computer as a function of space and/or time. The computer can include a processor and a memory storing computer-readable program code portions that, in response to execution by the processor, cause instructions to be provided to one or more components of a knitting machine in a desired sequence.
II. Spacer FabricsIn another aspect, spacer fabrics are described herein. The spacer fabrics can be formed in any manner described in Section I hereinabove and can have any features or properties of spacer fabrics described hereinabove in Section I. In some embodiments, for example, a spacer fabric described herein comprises a knit structure formed from a first yarn and a second yarn, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section. Further, the first yarn is a low thermal shrinkage yarn, and the second yarn is a high thermal shrinkage yarn. Moreover, in some cases, the knit structure is a unitary knit structure.
It is further to be understood that the first and second yarns of a spacer fabric described herein can have any properties, including any properties relative to one another, not inconsistent with the objectives of the present disclosure. For instance, as described above in Section I, in some embodiments, the second yarn of the spacer fabric shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C. Additionally, in some cases, heating the knit structure of the spacer fabric at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric, including in a manner described hereinabove. In some instances, a spacer fabric described herein, when unheated, is flat or substantially flat. Further, in some embodiments, a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.
Returning again to yarns of spacer fabrics described herein, in some embodiments, the first yarn is a monofilament yarn, such as a monocomponent monofilament yarn or a multi-component monofilament yarn. Other yarns may also be used as the first yarn. In addition, in some cases, the first yarn has a higher modulus than the second yarn. Further, in some embodiments, the second yarn is a multifilament yarn such as a monocomponent multifilament yarn or a multi-component multifilament yarn. Other second yarns may also be used.
Moreover, in some embodiments, the knit structure of a spacer fabric described herein is formed from a third yarn in addition to the first yarn and the second yarn, the third yarn differing from the first yarn and the second yarn. Any third yarn not inconsistent with the objectives of the present disclosure may be used, including a third yarn described hereinabove in Section I. For example, in some cases, the third yarn is a thermally fusible yarn, such as a third yarn that is thermally or heat-fusible at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension.
Similarly, in some cases, the knit structure of a spacer fabric described herein is formed from a fourth yarn in addition to the first yarn, the second yarn, and the third yarn of the knit structure, wherein the fourth yarn differs from the first yarn, the second yarn, and the third yarn. Any fourth yarn not inconsistent with the objectives of the present disclosure may be used, including a fourth yarn described hereinabove in Section I. In some embodiments, for instance, the fourth yarn has a color, texture, denier, and/or elasticity that differs from a color, texture, denier, and/or elasticity of the first yarn, the second, yarn, and/or the third yarn.
Additionally, as described above in Section I, a spacer fabric described herein can comprise a plurality of differing zones, the zones having one or more differing properties. For example, in some cases, the fabric comprises a plurality of zones having different compression resistances in a thickness direction of the fabric. In some such embodiments, the fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance, such as one or more first zones having a compression resistance of no more than 30 psi and one or more second zones having a compression resistance of at least 50 psi. As described above, the locations of such zones, in some instances, correspond to a pressure map of the fabric when in use in an end application, including an end application described above.
Moreover, as described above in Section I, a spacer fabric described herein can be used in a variety of end use applications. For example, in some embodiments, a spacer fabric described herein forms a portion of a seat or seat back. In other cases, a spacer fabric described herein forms a portion of footwear.
Some embodiments described herein are further illustrated in the following non-limiting examples.
ExamplesAs described above, disclosed herein are non-conventional, innovative ways of making three-dimensional weft knit spacer fabrics, either as continuous lengths of fabrics, panels or in different custom shapes such as for footwear insoles or chair seat and/or back panels as a cushioning/support member.
Several different textile yarns were generally used to produce spacer fabrics according to some embodiments described herein. A minimum of two (A+B), and more preferably three (A+B+C) material yarns were used in the following examples. Additional types of yarn could be added for color, texture, or other aesthetic or performance properties if desired, as described above.
Yarn A: Low Shrinkage Monofilament YarnsThis yarn type was used to make up the rigid skeleton portion of the spacer fabric, which provides one of two important elements of the 3D structure, and cushioning of the fabric. This Yarn A was typically a stiff higher modulus monofilament yarn that provides the primary stiffening agent in the fabric and the knit construction. Together with the yarn composition and modulus of the yarn as well as subsequent heat setting, these features all work together to provide the major contributors to the fabric's compressive resistance.
Yarn A, in some cases, is as follows:
A1. Monocomponent Monofilament, or A2. Multi-component (e.g., Biocomponent) Monofilament.Typical polymers could be based on polyester, polyamide, polypropylene (or other polyolefins), and other melt processing polymers that can be extruded into monofilament yarns. The multi-component monofilament yarn(s) could have a lower melting sheath material on the external coating of the yarn which would melt and flow to the adjacent yarns when the knitted fabric is heated after the knitting operation.
Yarn B: High Shrinkage YarnsThese yarns make up a second important component for the outer layer or skin of the fabric which reinforces and holds the skeleton in place due to the differential shrinkage as compared to Yarn A. The differential thermal shrinkage between Yarn A and Yarn B together with the knit construction causes the flat fabric, as knit, to form the thicker 3D structure after the fabric is removed from the knitting machine and is subjected to heat.
Yarns of the Yarn B type can typically be multifilament yarns for softness, high coverage, and easier knitting. But monofilaments could be used as well.
Type B yarns can be of different types, such as:
B1. Monocomponent Monofilament, B2. Multi-component (e.g., Bicomponent) Monofilament, B3. Monocomponent Multifilament, or B4. Multi-component (e.g., Bicomponent) Multifilament.Typical polymers can be based on polyester, polyamide, polypropylene (or other polyolefins), and other melt processing polymers that can be extruded into multifilament yarns.
Yarn C: Fusible YarnsThese (optional) yarns have a low melting point, and can serve as bonding materials to keep the fabric from losing form, and improve memory (resistance to permanent deformation due to cyclic compressive loading).
These yarns can be of different types, such as:
C1. Low shrinkage Monocomponent Monofilament
C2. Low shrinkage Multi-component (e.g., Bicomponent) Monofilament
C3. High shrinkage Monocomponent Monofilament
C4. High shrinkage Multi-component (e.g., Bicomponent) Monofilament
C5. Low shrinkage Monocomponent Multifilament
C6. Low shrinkage Multi-component (e.g., Bicomponent) Multifilament
C7. High shrinkage Monocomponent Multifilament
C8. High shrinkage Multi-component (e.g., Bicomponent) Multifilament
As described above, weft knit spacer fabrics described herein can be made on any weft knitting machine with a minimum of 2 sets of needles in either (FNB+BNB for Flat bed Machines, or Cylinder and Dial for Circular weft knitting Machines), and on any machine gauge, typically ranging from 5 gauge to 18 gauge (the number refers to the needles per inch in each of the respective needle beds). The gauges can be even finer if the knitting process is run on circular machines (the larger the number, the finer the gauge).
The yarn sizes can be based on the gauge of the equipment used to form the fabric. For example, on a 6.2 machine (12 gauge) the low shrinkage yarns could range from approximately 450 den to 1400 den, and the high shrinkage and fusible yarns could range from 50 den to 1200 den.
As described further herein, the knitting process in example embodiments described herein can be considered to comprise mirroring concave and convex structures made of the low shrinkage monofilament yarn, and then knitting the high shrinkage and fusible yarns in a similar fashion to cover the skeleton.
Different fabric patterns were accomplished using this technique, such as the fabric patterns illustrated in
Methods of making a spacer fabric described herein can provide fabrics that are very stable, as opposed to conventional weft knitted spacer fabrics, which tend to collapse on the wale's direction (see
Spacer fabrics according to some embodiments of the present invention have been formed that have load bearing capabilities (compressive resistance) ranging from about 4 psi to over 88 psi. As described further herein, the compressive resistance of a specific spacer fabric (or zone or region of a spacer fabric) can be selected based on one or more of the following:
-
- 1) Yarn ‘A’ Material Composition (e.g., choice of polymer)
- 2) Yarn ‘A’ Processing (e.g., coating)
- 3) Yarn ‘A’ Type (e.g., multi-component versus monocomponent)
- 4) Yarn ‘B’ Material Composition
- 5) Yarn ‘B’ Type (e.g., multi-component)
- 6) Yarn ‘C’ Presence or Absence, and Material Composition and Type
- 7) Knit Construction (see below for examples of different knit constructions according to various embodiments described herein) and
- 8) Heat setting conditions (e.g., time and temperature).
In
Various embodiments of the present invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the scope of the invention.
Claims
1. A method of making a spacer fabric comprising: wherein the second yarn shrinks more than the first yarn in the at least one dimension during the step of heating the knit structure.
- knitting a first yarn and a second yarn to form a knit structure, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section, and wherein the first yarn is a low thermal shrinkage yarn and the second yarn is a high thermal shrinkage yarn; and
- heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension,
2. The method of claim 1, wherein the second yarn shrinks by 10-90% in the at least one dimension during the step of heating the knit structure, based on an original size of the second yarn in the at least one dimension prior to the step of heating the knit structure.
3. The method of claim 1, wherein the second yarn shrinks at least two times as much as the first yarn in the at least one dimension during the step of heating the knit structure.
4. The method of claim 1, wherein the step of heating the knit structure increases a size of the void spaces in a thickness direction of the fabric.
5. The method of claim 4, wherein the step of heating the knit structure increases the size of the void spaces in the thickness direction of the fabric by at least 100%.
6. The method of claim 1, wherein the first yarn is a monofilament yarn.
7. The method of claim 6, wherein the first yarn is a monocomponent monofilament yarn or a multi-component monofilament yarn.
8. The method of claim 1, wherein the first yarn has a higher modulus than the second yarn.
9. The method of claim 1, wherein the second yarn is a multifilament yarn.
10. The method of claim 9, wherein the second yarn is a monocomponent multifilament yarn or a multi-component multifilament yarn.
11. The method of claim 1, wherein the knit structure is formed from a third yarn in addition to the first yarn and the second yarn, the third yarn differing from the first yarn and the second yarn.
12. The method of claim 11, wherein the third yarn is a thermally fusible yarn.
13. The method of claim 12, wherein the third yarn is fusible at the temperature of the step of heating the knit structure.
14-15. (canceled)
16. The method of claim 1, wherein the spacer fabric, after heating, comprises a plurality of zones having different compression resistances in a thickness direction of the fabric.
17. The method of claim 16, wherein the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance.
18. The method of claim 17, wherein the first zones have a compression resistance of no more than 30 psi and the second zones have a compression resistance of at least 50 psi.
19-24. (canceled)
25. A spacer fabric comprising:
- a knit structure formed from a first yarn and a second yarn,
- wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section;
- wherein the first yarn is a low thermal shrinkage yarn; and
- wherein the second yarn is a high thermal shrinkage yarn.
26. The fabric of claim 25, wherein the knit structure is a unitary knit structure.
27. The fabric of claim 25, wherein the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C.
28. The fabric of claim 25, wherein heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric.
29. The fabric of claim 25, wherein the fabric, when unheated, is flat or substantially flat.
30. The fabric of claim 25, wherein a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension.
31-46. (canceled)
Type: Application
Filed: Jan 31, 2018
Publication Date: Jan 2, 2020
Inventors: Juan Aristizabal (Greensboro, NC), Jeffrey W. Bruner (Leasburg, NC)
Application Number: 16/482,607
