Reflective fiber and reflective garment incorporating same

Abstract

Reflective fibers include prismatic fibers are configured to reflect solar radiation and may be incorporated into a textile or fabric and formed into garment or architectural textiles. A prismatic fiber may be a different material of polymer from a carrier material within the fiber or may be a void. A prismatic fiber or void has a triangular cross-sectional shape across the length of the fiber and may have one or more sides that are textured, corrugated or have a plurality of grooves to reflect light to increase the overall reflectance of light and solar radiation back in the atmosphere, away from the prismatic fiber. Light may enter the first side of the prismatic fiber and reflect off the base and out the second side of the prismatic fiber, wherein the texture or grooves act as a Fresnel lens. The fibers may be woven into a fabric, or laid down as a non-woven or configured on a substrate or support layer. A prismatic fiber may be made out of a polymeric material.

Description

REFLECTIVE FIBER AND REFLECTIVE GARMENT INCORPORATING SAMECross Reference To Related Applications

[0001] This application claims the benefit of priority to U.S. provisional patent application No. 63 / 596,250, filed on November 4, 2023; the entirety of which is hereby incorporated by reference herein.BACKGROUND OF THE INVENTION

[0002] Field of the Invention

[0003] The invention relates to reflective fabrics particularly for garments incorporating reflective fibers that include a reflective filler, such as a compound or particle, and particularly barium sulfate, and the reflective fibers may be prismatic fibers.Background

[0004] As temperatures continue to increase, there is a growing need to keep individuals cool when working or playing outside and keep structures cool to reduce energy used for air conditioning. Reflective fabrics are available but they often include a reflective film that is not permeable or breathable and therefore traps heat. These fabrics also reflect body heat back onto the wearer which makes them unsuitable for use as clothing.

[0005] Sunlight produces a wide spectrum of infrared (IR) radiation including Near-IR having a wavelength of 700 nm to about 1400 nm (0.7pm to 1 ,4pm). This wavelength range contains the majority of the solar thermal energy and therefore causes the most heating, and passes through most fabrics, such as those used in garments, and therefore causes heating of areas exposed to sunlight. Mid-IR has a wavelength of 1400nm to 3000nm (1.4pm to 3pm), which also causes heating but contains much less thermal energy and causes much less heating than Near-IR wavelengths. The human body emits excess body heat mostly in the Mid-IR range. Far-IR has a wavelength of 3000nm to 1mm (3pm to 1000pm) which is the upper range emitted by a human body and is often the wavelength used to identify people with infrared vision devices.

[0006] A reflective coating is described in U.S. patent No. 10,947,394 to Shaoyu Xu, et al.; the entirety of which is hereby incorporated by reference herein. The coating includes a resin and a first granular filler that may include aluminum silicate, pearl powder, silicon dioxide, calcium carbonate, barium sulfate, talcum powder, titanium dioxide, zinc sulfide, ceramic powder, ceramic bead, glass bead or a combination thereof. A second granular filler includes is aluminum oxide, zinc oxide, zirconium oxide, cerium oxide, lanthanum oxide, rhodium oxide, magnesium oxide, or a combination thereof.SUMMARY OF THE INVENTION

[0007] The invention is directed to reflective fabrics particularly for garments incorporating reflective fibers containing reflective filler particles inside the fibers, particularly barium sulfate, or reflective fibers which may be prismatic fibers or fibers which may contain prismatic shaped voids internally. The particles, such as barium sulfate, have high reflectance of solar near infrared radiation, which can add a substantial heat load to the body of a person when outside in the sunlight. A reflective fiber may be made of a polymeric material, such as a thermoplastic and may form a portion or substantially all of the fabric, wherein any seam thread or fasteners are not made of the reflective fiber. Reflective fiber may be made into a yarn, such as by twisting a plurality of reflective fibers together. Yarn may include other types of fibers such as other polymer fibers or natural fibers and the blend may be determined to provide effective reflectance and other properties, such as moisture wicking and / or durability or color.

[0008] The reflective filler, such as barium sulfate, may have a particle size or size dimension, length, width or diameter, that is within or near the near infrared wavelength range of about 0.5 to about 5pm and this size dimension may enhance reflectance from the reflective particles. The particle size may be about 0.1pm to about 10pm and preferably an average particle size, as determined by LS 13 320 XR Particle Size Analyzer, Beckman Coulter, Inc. (Brea, CA), between 0.1 to about 10pm and more preferably between 0.5 to about 5pm, and more preferably between 0.7 to about 3pm.

[0009] A reflective particle may be included in a polymer of a fiber in a concentration that enables the fiber or yarn made therefrom to reflect solar radiation and particularly solar radiation in the near infrared range of about 0.5 to about 5pm and preferably between 0.7pm to about 3pm. The concentration of the reflective particle by volume of the fiber of at least 3%, or about 5% or more, about 7.5% or more, about 10% or more, about 20% or more, about 50% or more and preferably 25% or less, or less than about 75%, or less than 50% of less, or any other range between and including the volume concentrations provided.

[0010] Barium Sulfate may be a desired reflective particle because it converts the near infrared wavelengths into wavelengths that are within the atmospheric window range of about 5pm to 8pm and this is within the atmospheric wavelength range.

[0011] A reflective fiber may include reflective particles homogeneously throughout the fiber, dispersed uniformly through the fiber, or may be concentrated more proximal to the outside surface of the fiber, wherein at least 75% of the reflective particles by are within 25% of the depth of the reflective fiber. As an example, if a fiber is circular having a diameter of 1mm, at least 75% of the reflective particles are within the outer periphery of the fiber, 0.25mm deep from the outer surface.

[0012] A reflective fiber may be a core-shell type fiber having a first polymer in the core and a shell of a second type of polymer and the reflective particle may be only in the shell of the core-shell fiber. This type of fiber may locate the reflective particles proximal to the outer surface of the fiber and may enhance reflective properties.

[0013] A reflective fiber may have a width or diameter of about 500pm or less, about 250pm or less, about 100pm or less, about 50pm or less, about 25pm or less, about 0.5pm or more or from 0.5pm to about 500pm or any other range between and including the values provided.

[0014] A reflective fabric or garment may include fibers of yarns including reflective fibers as described herein, that incorporate a reflective filler particle, such as barium sulfate therein. The reflective fibers may be a composite fiber including a polymer with the reflective particles within the polymer. The polymer may be a thermoplastic polymer such as polyester, nylon, polypropylene polyethylene and the like. The reflective particles, such as barium sulfate particles, may have a size dimension that is selected to more effectively reflect infrared radiation and particularly near IRinfrared radiation having as wavelength of about 0.7(jm to about 3pm, and may be 0.5pm to about 5pm. The reflective particles may be shaped for improved reflectance and may be elongated having a length dimension that is at least three times a width or diameter dimension or may be spherical or irregularly shaped. A reflective particle may be rod shaped with a cylindrical outer surface and diameter dimension that is less than a length dimension.

[0015] The barium sulfate particles may be included in a concentration by volume of the fiber of at least 3%, or about 5% or more, about 7.5% or more, about 10% or more, about 20% or more, about 50% or more and preferably 25% or less, or less than about 75%, or less than 50% of less, or any other range between and including the volume concentrations provided. A higher concentration may provide improved or a high degree of reflectance, however a higher concentration may make it difficult for processing and may diminish the mechanical properties and therefore a preferred volume concentration may be from about 3% to about 25%.

[0016] The reflective fabric may include an effective amount of the reflective fibers and a concentration of non-reflective fibers, or fibers that are not composites including a reflective particle. The ratio of the reflective fibers to the non-reflective fibers by weight of the fabric may be about 0.2:1 or more, about 0.5:1 or more, about 1 :1 or more, about 1.25:1 or more, about 1.5:1 or more, about 1.75:1 or more, and any range between and including the ratios provided. The reflective yarns may be more costly to produce than non-reflective fibers and therefore keeping the concentration of reflective fibers to a minimum while still providing effective reflectance may be preferred. Therefore, a preferred ratio may be about 0.2:1 to about 1.5:1.

[0017] The reflective fibers may be included in a yarn comprising a plurality of fibers and the reflective fibers may be configured on an outside surface of the yarn and non-reflective fibers may be configured on an interior of the yarn. Also, a reflective fabric may include a concentration of reflective yarns and a concentration of non- reflective yarns. The yarns may be arranged with the reflective yarns in one of the warp or weft direction and non-reflective yarns in the opposing warp or weft direction.

[0018] The polymer of the reflective fiber and polymer for non-reflective fibers may be chosen to improve heat transmission from a person out through the reflective fabric and / or for moisture management properties. A natural fiber may be used in a reflective yarn along with the reflective fiber and also may be used as a non- reflective fiber or non-reflective yarn in the reflective fabric.

[0019] Polyester is widely used in fibers for sportswear because it is low cost and has excellent mechanical properties. However, it blocks the majority of body heat from being emitted through the fabric. This low emissivity of mid-infrared body heat is a benefit if trying to stay warm in cold weather but it is a detriment when trying to stay cool in hot weather.

[0020] Most sportswear marketed as "cooling" relies on the principle of wicking sweat away from the body on the skin side of the fabric through capillary action to the external side of the fabric where it can evaporate into the atmosphere. However, this evaporation mechanism only works well in low humidity. Once the ambient relative humidity reaches about 50% or higher, sweat evaporates much more slowly or not at all which completely negates this cooling mechanism. Meanwhile, the increased heat load from the sun is still acting on the body.

[0021] Nylon has a higher emissivity of body heat infrared wavelengths and also a higher thermal conductivity than polyester so it feels cooler to the touch and allows more body heat to escape than polyester. However, nylon is more expensive so it tends to be not be used in most sportswear to keep costs down. Nylon also does little or nothing to reflect solar heat so neither polyester or nylon reduce the solar heat load on a person.

[0022] Polyethylene has the highest thermal emissivity of body heat among commercially available fibers. However, it is not normally used in sportswear or any fabric for clothing due to its low mechanical strength. There is some sportswear on the market that uses yarns that are a blend of polyethylene and polyester to improve the thermal emissivity of body heat so the wearer feels cooler, but it is meant to be worn indoors to allow for reduced use of air conditioning as it also does nothing to reflect solar heat.

[0023] An idealized fabric for sportswear to keep the wearer as cool as possible under hot sunny conditions would need to have a combination of properties to deal with several heating and cooling mechanisms. Ideally it should reflect the maximumamount of solar heat radiation in the near-infrared wavelength range. It should also allow for air flow through the fabric to maximize heat loss due to convection, and maximize the ability of the fabric to wick moisture (sweat) away from the body to the atmosphere via evaporation, which to reiterate only works under low humidity conditions. It should also maximize the amount of mid-infrared body heat that can be emitted through the fabric via radiation (emissivity). And lastly, it should maximize the thermal conductivity of the fabric material to allow for a maximum amount of body heat through the fabric via conduction. While it may be possible to construct such fabric and yarn from one type of fiber, it is more likely that a yarn that is a blend of fibers with these properties would achieve the best cooling while maintaining the desired mechanical strength, comfort, washability, etc. Also the type of weave used to construct the fabric will have an effect on all cooling mechanisms (conduction, convection, radiation, and moisture wicking), but a discussion of the ideal weave to achieve these results is beyond the scope of this patent.

[0024] A yarn incorporating a reflective fiber may be a blend of two or more fibers. For example, one of the fibers may be polyethylene to allow for improved emissivity of mid-infrared body heat, one of the fibers may be nylon to allow for improved thermal conductivity and improved mechanical strength, and one of the fibers may have hollow prismatic structures within the fiber or a filler material consisting of particles of Barium Sulfate, Teflon, or other reflective materials that have a high reflectivity of the near-infrared wavelengths of solar radiation that add heat load to the wearer. This fiber may be made from polyethylene, nylon, polyester, or a different type of polymer. The % of each type of fiber in a blended yarn would vary depending on the use case of the fabric in question and which properties need to be maximized, with considerations given to cost, manufacturability, wearability, comfort, and the like.

[0025] Reflective fibers may be prismatic fibers configured to reflect solar radiation. An exemplary prismatic fiber has a triangular cross-sectional shape that is configured to direct light from a first side, into the prismatic fiber and off of a base side or third side and then out a second side. The triangular prismatic fiber may have smooth surfaces or may have one or more sides that have a textured or grooved surface. In an exemplary embodiment, the first side and in some cases the first and second side of a prismatic fiber are textured, corrugated or have a pluralityof surface grooves to reflect light to increase the overall reflectance of light and solar radiation back in the atmosphere, away from the prismatic fiber. The light may enter the first side of the prismatic fiber and be directed by the textured surface down toward the base of the fiber where the light reflects off the base and out the second side of the prismatic fiber. The texture or grooves may act as a Fresnel lens to direct the light for effective reflectance. The fibers may be woven into a fabric, or laid down as a non-woven, or configured on a substrate or support layer, such as a fabric or film or foil and they may be aligned with the length of the fibers in parallel to substantially cover the surface of the substrate or at least 80% or more, and preferably 90% or more.

[0026] An exemplary prismatic fiber may have a prismatic shape and may be incorporated into fiber or yarn and further incorporated into a textile such as a garment. An exemplary prismatic fiber may include reflective voids, such as prismatic voids, circular voids, or polygonal or irregularly shaped voided configured within the fiber. The voids may be elongated and extend along the length of the fiber and have a cross-sectional shape defined across the cross-section of the fiber. The interface between the reflective void and the material of the fiber, such as a polymer, causes the reflectance of light. The reflective voids may extend a length along the fiber and a fiber may include a random or arranged pattern of prismatic fibers or reflective prismatic voids along the fiber. Note that the reflective voids may be triangular in cross-sectional shape or circular or oval or any other shape that may be conducive to creating a reflective interface between the void and the material of the fiber, such as a polymer. The index of refraction of the fiber material may be effectively different from the void to produce reflection of the light as it passes through the fiber. It may be preferred that the material of the fiber be translucent to allow light to pass therein and be incident on the reflective void or voids.

[0027] An exemplary prismatic fiber may be made out of an organic or synthetic material including a polymeric material selected from, but not limited to, nylon, polyester, polyethylene (PE), An advantage of PE and nylon over polyester is that they are relatively more transparent to infrared body heat so they allow more body heat to escape. The prismatic fibers may be made out of other materials which may be more advantageous for non-clothing applications such as roofing or building material. Other materials include ceramics, glass or composite materials. Forroofing applications and other non-apparel applications, the prismatic fibers of the present may be cut into pieces and included into other materials such as coating and exterior layers. A roofing material may have the prismatic fibers in an outer coating or paint for example.

[0028] An exemplary prismatic fiber may be small in size and have a maximum side length of about 0.5 micro-meter (microns or pm) or more, about 1pm or more, about 5pm or more, about 10pm or more, about 15pm or more about 25pm or more, and even about 50pm or more and any range between and including the values provided. A preferred range of reflective prismatic fiber size is between about 0.5pm to about 5pm or from about 1.0pm to about 5pm or from about 1.0pm to about 3pm, or even 2pm to 3pm, the preferred size range being chosen as to best reflect the desired wavelengths of IR light.

[0029] A reflective prismatic fiber may be used in a garment to reflect Far IR wavelengths to prevent detection from infrared vision devices and therefore a garment or fabric may utilize reflective prismatic fiber having a larger size, such as from about 3pm to about 1mm or from about 3pm to about 0.5mm or from about 10um to about 50mm and any other range between and including the sizes provided. Sizes are fiber side length dimensions as detailed herein. Also, a fabric or garment my utilize reflective prismatic fibers that are in different ranges to provide a more camouflage effect, wherein some reflect one range of wavelength of the Far IR while others reflect wavelengths of a different range of Far IR, wherein the ranges do not overlap for example or overlap. The side lengths therefore may be at least 50% different from a first set of reflective prismatic fibers to a second set of reflective prismatic fibers.

[0030] A prismatic fiber may have all sides textured or only one or two sides textured. In an embodiment a first and second side of the prismatic fiber comprises groove and the base side is flat, to aid in reflectance off this surface and back out of the fiber.

[0031] An exemplary prismatic fiber may have a length to side-length ratio that is high, such as about five or more, about 10 or more, or even about 50 or more when the fibers are cut and used as a filler in another material, or about 1 ,000 or 10,000 or even thousands or more when used as a long fiber. An exemplary prismatic fiber may have a length that is meters in length or even hundreds of meters in length.

[0032] An exemplary prismatic fiber may have an inclusive angle between the first side and the second side. The cross-sectional shape of the prismatic fiber may be substantially an equilateral triangle wherein the first side, second side and base are within about 20% of each other in length. The prismatic fiber may have a cross- sectional shape that is substantially an isosceles triangle having the first and second side being substantially equal in length, within about 20% of each other in length, with the base being substantially larger or shorter in length by at least 20% than either the first side or second side. The prismatic fiber may have a cross-sectional shape that is substantially an obtuse triangle having an inclusive side angle that is greater than 90 degrees.

[0033] The prismatic fiber may have an index of refraction of about 1 .1 or more about 1 .2 or more about 1 .3 or more, about 1 .4 or more and even about 1 .6 or more, and any range between and including the values provided. As a comparison, a metal foil has a refractive index of about 1 .3 and a mirror is about 1 .6 or more.

[0034] A solar radiation reflective fabric includes a fiber that may have reflective particle. The fiber may be part of a garment or sunshade and may be configured as a yarn. A reflective yarn may consist of reflective fibers or may be a composite reflective fiber that includes a reflective fiber and a secondary fiber such as a polymeric or synthetic fiber and / or a natural fiber. A solar radiation reflective fabric may include reflective yarn or composite reflective yarns and may also include a secondary yarn, a yarn that is not reflective as described herein and this secondary yarn may be polymeric or synthetic or a natural yarn including only natural fibers such as wool, cotton and the like.

[0035] The summary of the invention is provided as a general introduction to some of the embodiments of the invention and is not intended to be limiting. Additional example embodiments including variations and alternative configurations of the invention are provided herein.BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0036] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification,illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0037] Figure 1 shows a cross section of an exemplary reflective fabric comprising a plurality of prismatic fibers configured on the outside surface and comprising grooved sides configured to direct the incident light back such that the light is reflected off the base and back out of the prismatic fiber.

[0038] Figure 2 shows a cross-sectional view of an exemplary prismatic fiber having a first and second side with grooves configured to direct incident light for reflection off of the base.

[0039] Figure 3 shows a top view of an exemplary reflective fabric having a plurality of prismatic fibers configured in parallel on the outside surface of the fabric.

[0040] Figure 4 shows a cross section of an exemplary reflective fabric comprising a plurality of layers of prismatic fibers configured in parallel and in an offset arrangement, with a first row of prismatic fibers proximal to the reflective outer fabric layer and a second row of prismatic fibers configured between each of the prismatic fibers of the first row and more proximal to an outside of the reflective fabric.

[0041] Figure 5 shows a top view of the exemplary reflective fabric shown in FIG. 4, having said rows of prismatic fibers configured in parallel on the outside surface of the fabric.

[0042] Figure 6 shows a cross section of an exemplary reflective fabric comprising a plurality of layers of prismatic fibers configured in an orthogonal configuration, with a first row of prismatic fibers configured in a first orientation and the second row of prismatic fibers configured on top of the first row and in an offset angular orientation, such a substantially orthogonal, or from about 80 degrees to 100 degrees.

[0043] Figure 7 shows a top view of the exemplary reflective fabric shown in FIG. 4, having said rows of prismatic fibers configured in parallel on the outside surface of the fabric.

[0044] Figure 8 shows a cross section of an exemplary reflective fabric comprising a plurality of prismatic fibers configured on the outside surface of the radiant fabric and having a triangular cross-sectional shape configured to direct the incident light back such that the light is reflected off the base and back out of the prismatic fiber.

[0045] Figure 9 shows a cross-sectional view of an exemplary prismatic fiber shown in FIG. 8, having a first and second side configured to direct incident light for reflection off of the base.

[0046] Figure 10 shows a top view of the exemplary reflective fabric shown in FIG. 8, having a plurality of prismatic fibers configured in parallel on the outside surface of the fabric.

[0047] Figure 11 shows a cross-sectional view of an exemplary composite fiber having prismatic fibers of the same or of a second material configured around the perimeter of the fiber core.

[0048] Figure 12 shows a cross-sectional view of an exemplary composite fiber having prismatic fibers contained within the outer perimeter of the fiber to reflect sunlight, where the prisms may be comprised of second material with different refractive index from the main fiber material, or hollow and filled with air or another gas.

[0049] Figure 13 shows a cross-sectional view of an exemplary composite fiber having prismatic fibers within a core portion of an outer portion of the composite fiber, where the core prisms or the entire core may be comprised of second material with different refractive index from the main fiber material, or hollow and filled with air or another gas

[0050] Figure 14 shows a cross-sectional view of an exemplary composite fiber having prismatic fibers configured uniformly through the composite fiber, where the prisms may be comprised of second material with different refractive index from the main fiber material, or hollow and filled with air or another gas.

[0051] Figure 15 shows a cross-sectional view of an exemplary reflective fiber including reflective voids configured within the fiber, wherein the reflective voids are configured in an arranged orientation with the base proximal the center of the fiber and the height axis extending radially from a center of the reflective fiber.

[0052] Figure 16 shows a cross-sectional view of an exemplary reflective fiber with a reflective void configured centrally within the fiber.

[0053] Figure 17 shows a cross-sectional view of an exemplary reflective fiber including reflective voids or air filed portions within the composite fiber.

[0054] Figure 18 shows a cross-sectional view of an exemplary reflective fiber with reflective voids are configured throughout the reflective fiber.

[0055] Figure 19 shows a person donning a solar radiation reflective fabric comprising reflective fibers in the garment and standing under a sunshade incorporating a fabric having reflective fibers as described herein.

[0056] Figure 20 shows a scanning electron micrograph (SEM) of reflective particles having an elongated rod shape with a length dimension that is more than three times a width or diameter dimension.

[0057] Figure 21 shows a graph of radiative capacity versus wavelength of radiation and the near infrared range 0.7pm to about 250 pm that can produce heat when passing through a garment and becoming incident on a person.

[0058] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Some of the figures may not show all of the features and components of the invention for ease of illustration, but it is to be understood that where possible, features and components from one figure may be included in the other figures. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0059] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of "a" or "an" are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0060] Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0061] Referring to FIGS. 1 to 3, an exemplary reflective fabric 10 comprises a plurality of prismatic fibers 30 configured on the outside surface 12 and comprising grooved sides configured to direct the incident light back such that the light is reflected off the base 36 and back out of the prismatic fiber. The first side 32 and second side 34 have a side length 35 and are configured at an inclusive side angle 33 to each other. Each of the first and second sides has a plurality of grooves 40 that have a groove depth 42 along the groove base 43 and a groove height 46 and along the groove wall 45. The groove base and groove wall are configured at an inclusive angle 44. The groove base 43 extends inward or generally along a width 37 of the prismatic fibers and the groove wall extends upward or generally along a height 38 of the prismatic fibers. Each of the first and second sides may have a plurality of grooves. The base 36 is configured proximal to the reflective outer fabric 60 or the interior fabric layer 70. The sides of the prismatic fibers extend away from the interior fabric layer toward an outside of the reflective fabric. The incident light 20 is reflected by the planes of the grooves toward the base 36 of the prismatic fiber and is reflected back up and out of the prismatic fiber. The base may be reflective and / or may be configured on a reflective outer fabric layer, wherein the incident light within the prismatic fiber is reflected by the reflective outer fabric layer. The exemplary reflective fabric 10 may comprise one or more fabric layers.

[0062] As shown in FIG. 2, the prismatic fibers 30 have textured surfaces on the first side 32 and the second side 34. As shown, the prismatic fiber has grooves 40 with a groove depth 42 and groove height 46 along the first side 32 and second side 34. It should be noted that the prismatic fiber may have grooves on one, two or all three of the sides of the fiber including the first side 32, second side 34 and base 36. The prismatic fibers have a cross-sectional shape that forms a substantially equilateraltriangle wherein the first side, second side and base are within about 20% of each other in length. The cross-sectional shape of the prismatic fibers may form an isosceles triangle having the first and second side being substantially equal in length and the base being larger or shorter in length than either the first or second sides. The cross-sectional shape of the prismatic fibers may be an acute triangle with each angle being less than 90 degrees. The cross-sectional shape of the prismatic fibers may be a right triangle with one angle, such as the inclusive side angle, that is substantially 90 degrees, or from about 90 to 100 degrees. The cross-sectional shape of the prismatic fibers may be an obtuse triangle having one angle, such as the inclusive side angle, that is greater than 90 degrees.

[0063] As shown in FIG. 3, a reflective fabric 10 has a plurality of prismatic fibers 30, 30’ aligned with the length 39 of the prismatic fibers extending parallel along the fabric. The prismatic fibers have an aspect ratio of length 39 to the width 37 (shown in FIG. 1 ) that is 5 or more, 10 or more, 20 or more, 100 or more and or even thousand or more and any range between and including the aspect ratios provided. The prismatic fibers extend along a length axis 301.

[0064] Referring now to FIGS. 4 and 5, an exemplary reflective fabric 10 comprises a first row 31 of aligned prismatic fibers 30 coupled to the prismatic fabric, such as to the reflective outer fabric layer 60 or to the interior fabric layer 70, and a second row 81 of prismatic fibers 80 aligned with said first row of aligned prismatic fibers and configured between the prismatic fibers of the first row. A gap 89 may be configured between the base 86 of the second row prismatic fibers and the side surfaces of adjacent first row prismatic fibers. This arrangement may provide additional reflective surfaces to reduce any incident light hitting the fabric directly. Also, the gap may provide some additional insulation. As shown in FIG. 5, the first row and second row of prismatic fibers are substantially aligned and are parallel having a length axis 301 , within about 20 degrees of parallel and preferably without about 10 degrees of parallel and even more preferably within about 5 degrees of parallel.

[0065] Figure 4 shows a cross section of an exemplary reflective fabric comprising a plurality of layers of prismatic fibers configured in parallel and in an offset arrangement, with a first row 31 of prismatic fibers 30 proximal to the reflective outer fabric layer and a second row 81 of prismatic fibers 80 configured between each ofthe prismatic fibers of the first row and more proximal to an outside of the reflective fabric.

[0066] Referring now to FIGS. 6 and 7, an exemplary reflective fabric 10 comprises a first row 31 of aligned prismatic fibers 30 coupled to the prismatic fabric, such as to the reflective outer fabric layer 60 or to the interior fabric layer 70, and a second row 81 of prismatic fibers 80 configured on top of said first row of aligned prismatic fibers. The first row of prismatic fibers have a length 39 and the second row has a length 39’. A gap 89 may be configured between the base 86 of the second row of prismatic fibers and the side surfaces of the first row of prismatic fibers. This arrangement may provide additional reflective surfaces to reduce any incident light hitting the fabric directly. Also, the gap may provide some additional insulation. The second row of prismatic fibers are configured in an offset angular orientation, with respect to the first row of prismatic fibers, such as substantially orthogonal, or from about 80 degrees to 100 degrees, as shown.

[0067] Referring now to FIGS. 8 to 10, an exemplary reflective fabric 10 comprises a plurality of reflective prismatic fibers 30 configured on the outside surface and having a triangular cross-sectional shape. The shape of the fiber is configured to direct the incident light back 20 through the prismatic fiber, wherein it is reflected off the base 36 and back out of the prismatic fiber as reflected light 28. As shown in FIG. 9, the exemplary prismatic fiber has a first side 32 and second side 34 and a base 36. As shown in FIG. 10, the exemplary reflective fabric 10 has a plurality of prismatic fibers configured in parallel on the outside surface of the fabric. The sides of the reflective prismatic fiber shown in FIG. 9 are smooth, wherein the side is planar with no grooves, or no texture having a depth of more than 10% of the length of the side or even no more than 5% of the length of the side.

[0068] Referring now to FIGS. 11 and 12, an exemplary composite fiber 90 has reflective prismatic fibers 93, like those shown in FIG. 9 configured in a composite fiber 90 geometry. As shown in FIG. 11 , the reflective prismatic fibers 93 are configured about the perimeter or outer surface 96 of the composite fiber 90. The reflective prismatic fibers 93 may extend over the outer surface 96 of the composite fiber 90 and substantially cover the outer surface area of the fiber, or about 75% or more of the outer surface area of the fiber, or at least 85% or more, or at least 95% or more. As shown in FIG. 12, the reflective prismatic fibers 93 are configured withinthe outer surface 96 of the composite fiber 90. The composite fiber may include a first polymer 92 that makes up the reflective prismatic fibers 93 and second polymer 94 that is the remaining portion of the composite fiber 90. As shown in FIG. 11 , the second polymer 94 is configured internal or inside of the first polymer 92 of the reflective prismatic fibers 93. As shown in FIG. 12, the second polymer 94 is configured outside of and inside of the reflective prismatic fibers 93.

[0069] Referring now to FIGS. 11 and 12, an exemplary reflective fiber 11, is a composite fiber 90 has reflective prismatic fibers 93, like those shown in FIG. 9 configured in a composite fiber 90 geometry. As shown in FIG. 11 , the reflective prismatic fibers 93 are configured about the perimeter or outer surface 96 of the composite fiber 90. The reflective prismatic fibers 93 may extend over the outer surface 96 of the composite fiber 90 and substantially cover the outer surface area of the fiber, or about 75% or more of the outer surface area of the fiber, or at least 85% or more, or at least 95% or more. As shown in FIG. 12, the reflective prismatic fibers 93 are configured within the outer surface 96 of the composite fiber 90. The composite fiber may include a first polymer 92 that makes up the reflective prismatic fibers 93 and second polymer 94 that is the remaining portion of the composite fiber 90. As shown in FIG. 11 , the second polymer 94 is configured internal or inside of the first polymer 92 of the reflective prismatic fibers 93. As shown in FIG. 12, the second polymer 94 is configured outside of and inside of the reflective prismatic fibers 93.

[0070] Referring now to FIGS. 13 and 14, an exemplary composite fiber 90 has reflective prismatic fibers 93, like those shown in FIG. 9 configured in a composite fiber 90 geometry. As shown in FIG. 13, the reflective prismatic fibers 93 are configured about the outer portion or outer surface 96 of the composite fiber 90 and are retained within a second polymer 94. The reflective prismatic fibers 93 may be embedded within a carrier polymer 98 and this composite of reflective prismatic fibers 93 and carrier polymer 98 may extend as a shell over a core, or over the outer surface or outer portion 91 of the composite fiber, portion extending around a second polymer that may be a core 95 of the composite fiber. A core polymer 97 may be configured as the core 95 of the fiber or be configured inside of the reflective prismatic fibers 93 and carrier polymer 98. Note that the reflective prismatic fibers93 may be oriented in a particular direction within this outer portion of the compositefiber 90 or may have a random orientation. As shown in FIG. 14, the reflective prismatic fibers 93 are configured within the carrier polymer 98, or second polymer 94 throughout the cross section of the composite fiber. Again, the reflective prismatic fibers 93 may be oriented in a particular direction within this outer portion of the composite fiber 90 or may have a random orientation.

[0071] The reflective prismatic fibers 93 may as shown in FIGS. 12 to 14 may have a size side length 35, as shown in FIG. 9 of about 1 pm to about 5pm and preferably from about 1pm to about 3pm for reflectance of the near infrared radiation from the sun, the wavelength that cause the most heating.

[0072] As shown in FIGS. 15 to 18, an exemplary reflective fiber 11 , may be a composite fiber 110 including reflective voids 113 such as reflective prismatic voids as shown in FIGS. 15 and 16, or air filed shaped portions within the composite fiber 110. The difference in index of refraction from a first polymer 112 or carrier polymer 118 around the reflective voids 113, to air or gas within the reflective voids 113, may effectively reflect light from the reflective fiber 11. The reflective prismatic voids may have a height or side lengths of about 0.5pm to about 3pm and preferably about 1 pm to about 2pm to enable effective reflection of light. An exemplary reflective prismatic void has a triangular cross-sectional shape comprising a first side, a second side; and a base side as shown in FIG. 9, wherein the sides of the reflective prismatic void are formed by the carrier polymer 118 around the void.

[0073] As shown in FIG. 15, the reflective voids 113 are configured in an arranged orientation with the base 136 proximal the center of the fiber and the height axis 135, extending from a center location across the base up through the top 133 or intersection of the first side 132 and second side 134 of the reflective void 113. This may be a preferred orientation as the light incident on the outer surface 116 of the composite fiber 110 may be incident then on the first side 132 and second side 134 of the reflective voids 113. The fiber may include a first polymer 112 and may include the same polymer in the core 115 or a second polymer 114 in the core. The outer portion 111 may be connected to the core 115 by the first and / or second polymers to provide stability of the fiber.

[0074] As shown in FIG. 16, a reflective void 113 is configured centrally within the fiber or forms a core 115 of the fiber. The fiber may have a cross-sectional width119 such as the diameter as shown that is about 10pm or more, about 50pm or less,or between about 10pm and 20pm. Note that one or more reflective voids 113 may be configured randomly in the composite fiber 110 or configured in the core 115 of the fiber, or only configured in an outer portion 111.

[0075] As shown in FIGS. 17 and 118, an exemplary reflective fiber 11, may be a composite fiber 110 including reflective voids 113, or air filed portions within the composite fiber 110. As shown in FIG. 117, the reflective voids 113 are configured in the outer portion 111 around the core 115 of the composite fiber. The outer portion 111 may be a thin layer around a core 115 and may have a thickness of about 100pm or less, about 50pm or less for example. The reflective voids 113 are configured in a carrier polymer 118, such as a first polymer 112, and the core 115 may be second polymer 114 or core polymer 117.

[0076] As shown in FIG. 18, the reflective voids 113, are configured throughout the reflective fiber 11 . The reflective voids 113 may be configured randomly or in an arranged orientation throughout the composite fiber 110. Also, the reflective voids 113 may have a length and extend along a length of the reflective fiber 11, forming tubes along the fiber length. The length of a reflective void along the fiber may be 50pm or more, 100pm or more, 1mm or more, 1cm or more, 10cm or more, 1m or more and any range between and including the length values provided. The reflective voids 113 may extend the full length of the fiber.

[0077] The reflective fibers 11 shown in FIGS. 15 to 18 may be combined with other fibers to form a fabric and may form the outer portion of a composite yarn or fiber. The reflective fibers may be twisted or otherwise configured around one or more base fibers, for example.

[0078] Figure 19 shows a person donning a solar radiation reflective fabric 300 comprising reflective fibers 310 in the garment 320. The solar radiation reflective fabric may be included in the garments the person is wearing including the jacket 324, the shirt 325, the hat 322 and pant 326. The person is standing under a sunshade 380 having the solar radiation reflective fabric 300’ configured between the sun, the source of solar radiation, and the person and the solar radiation reflective fabric 300’ comprises reflective fibers 310’. The solar radiation reflective fabric 300 includes reflective fibers 310 as described herein and these fibers may form yarn 330 and the fabric may also include a secondary fiber 333. As described herein, the secondary yarn may be a consists of natural fibers, or may include a polymeric fiberor blend thereof but may not include reflective particles, but may include reflective voids. The reflective fibers include a reflective particle 400 such as those shown in FIG. 20. A reflective garment 320 may be a hat 322, a jacket 324, a shirt 325 or pants 326.

[0079] Figure 20 shows a scanning electron micrograph of reflective particles having a rod shape with a length dimension that is greater than the diameter dimension by more than three to one to produce an elongated reflective particle. Note that the scale bar of 5um indicates that the diameter is less than 5um and therefore in the near infrared wavelength range. The reflective particle may have a particle size in the range of 0.1pm to about 10pm with the preferred being about 0.5 to about 10pm.

[0080] Figure 21 shows a graph as shown in in U.S. patent No. 10,947,394 to Shaoyu Xu, of radiative capacity versus wavelength of radiation and the near infrared range 0.7pm to about 250pm can produce heat when passing through a garment and becoming incident on a person.

[0081] It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the scope of the invention. Specific embodiments, features and elements described herein may be modified, and / or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A solar radiation reflective fabric comprising: a) fiber comprising reflective particles therein that reflects infrared radiation.

2. The solar radiation reflective fabric of claim 1, wherein the reflective particle is barium sulfate.

3. The solar radiation reflective fabric of claim 1, wherein the barium sulfate has volume concentration of the reflective fiber of at least 5%.

4. The solar radiation reflective fabric of claim 3, wherein a volume concentration of the barium sulfate in the reflective fiber is no more than 50%.

5. The solar radiation reflective fabric of claim 3, wherein a volume concentration of the barium sulfate in the reflective fiber is no more than 25%.

6. The solar radiation reflective fabric of claim 3, wherein the barium sulfate has a size dimension of between 0.5pm and 5pm.

7. The solar radiation reflective fabric of claim 6, wherein the size dimension is a diameter of the barium sulfate.

8. The solar radiation reflective fabric of claim 3, wherein the fiber comprises a polymer and wherein said reflective particles are dispersed in said polymer.

9. The solar radiation reflective fabric of claim 8, wherein the polymer is polyester.

10. The solar radiation reflective fabric of claim 8, wherein the polymer is nylon.

11. The solar radiation reflective fabric of claim 8, wherein the polymer ispolypropylene.

12. The solar radiation reflective fabric of claim 8, wherein the polymer is polyethylene.

13. The solar radiation reflective fabric of claim 3, wherein the fiber consists of a polymer and said reflective particles.

14. The solar radiation reflective fabric of claim 3, wherein at least 75% of the reflective particles are configured within 25% of a depth of the reflective fiber.

15. The solar radiation reflective fabric of claim 1 , wherein the fiber comprises a polymer and wherein said reflective particles are dispersed in said polymer.

16. The solar radiation reflective fabric of claim 15, wherein the polymer is polyester.

17. The solar radiation reflective fabric of claim 15, wherein the polymer is nylon.

18. The solar radiation reflective fabric of claim 15, wherein the polymer ispolypropylene.

19. The solar radiation reflective fabric of claim 15, wherein the polymer is polyethylene.

20. The solar radiation reflective fabric of claim 15, wherein the fiber consists of a polymer and said reflective particles.

21. The solar radiation reflective fabric of claim 15, wherein at least 75% of the reflective particles are dispersed within 25% of a depth of the reflective particle.

22. The solar radiation reflective fabric of claim 1 , wherein the fabric is a component of a garment.

23. The solar radiation reflective fabric of claim 22, wherein the fabric a woven fabric.

24. The solar radiation reflective fabric of claim 22, wherein the woven fabric comprises a secondary fiber.

25. The solar radiation reflective fabric of claim 24, wherein the secondary fiber is a polymeric fiber.

26. The solar radiation reflective fabric of claim 25, wherein the secondary fiber and the reflective fiber are configured into a composite yarn.

27. The solar radiation reflective fabric of claim 25, wherein the secondary fiber form a first yarn and wherein the reflective fiber is in a second yarn.

28. The solar radiation reflective fabric of claim 24, wherein the secondary fiber is a natural fiber.

29. The solar radiation reflective fabric of claim 28, wherein the secondary fiber and the reflective fiber are configured into a composite yarn.

30. The solar radiation reflective fabric of claim 28, wherein the secondary fiber forms a first yarn and wherein the reflective fiber is in a second yarn.

31. The solar radiation reflective fabric of claim 1 , wherein the fabric is part of a sunshade.

32. The solar radiation reflective fabric of claim 1 , wherein the reflective fiber is a composite fiber comprising: i) a length, ii) a carrier material; and iii) a reflective void configured within the carrier material.

33. The solar radiation reflective fabric of claim 32, wherein the reflective void is circular is cross-sectional shape.

34. The solar radiation reflective fabric of claim 32, wherein the reflective void has a triangular cross-sectional shape and is a reflective prismatic void comprising: a) a first side; b) a second side; c) a base side; and d) a side length of between 0.5pm and 5pm.

35. The solar radiation reflective fabric of claim 34, wherein the reflective prismatic void has a side length of between 1pm and 3pm.

36. The solar radiation reflective fabric of claim 35, wherein the fabric is further formed into a garment and wherein the garment is worn by a person.

37. The solar radiation reflective fabric of claim 34, wherein the reflective prismatic void has a side length of between 2pm and 3pm.

38. The solar radiation reflective fabric of claim 34, wherein the first side is textured comprising a plurality of grooves having a groove depth and groove height, wherein the grooves extend along the length of said prismatic fiber.

39. The solar radiation reflective fabric of claim 34, wherein the second side is textured comprising a plurality of grooves having a groove depth and groove height,40. The solar radiation reflective fabric of claim 34, wherein the base is textured comprising a plurality of grooves having a groove depth and groove height, wherein the groove extends along the length of said prismatic fiber.41 . The solar radiation reflective fabric of claim 34, wherein the first side extends at an inclusive angle to the second side.

42. The solar radiation reflective fabric of claim 34, wherein the reflective prismatic void has a cross-sectional shape that is substantially an equilateral triangle wherein the first side, second side and base are within about 20% of each other in length.

43. The solar radiation reflective fabric of claim 34, wherein the reflective prismatic void has a cross-sectional shape that is substantially an isosceles triangle having the first and second side being substantially equal in length and the base being substantially larger or shorter in length by at least 20% than either the first side or second side.

44. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.2.

45. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.3.

46. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.5.

47. The solar radiation reflective fabric of claim 32, wherein the carrier material is a carrier polymer.

48. The solar radiation reflective fabric of claim 47, wherein the carrier polymer is a hydrocarbon polymer.

49. The solar radiation reflective fabric of claim 32, wherein the composite fiber comprises a plurality of reflective voids within the carrier material.

50. The solar radiation reflective fabric of claim 49, wherein the reflective voids are configured in an outer portion of the composite fiber.

51. The solar radiation reflective fabric of claim 50, wherein the outer portion extends over a core of the composite fiber.

52. The solar radiation reflective fabric of claim 51 , wherein the reflective voids are configured only in an outer portion of the composite fiber and wherein said core of the fiber is comprises a second polymer.

53. The solar radiation reflective fabric of claim 32, wherein the reflective voids are configured throughout the composite fiber.

54. The solar radiation reflective fabric of claim 32, wherein the reflective voids are configured in the core of the composite fiber.

55. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.2.

56. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.3.

57. The solar radiation reflective fabric of claim 32, wherein the carrier material has an index of refraction of at least 1.5.

58. The solar radiation reflective fabric of claim 32, wherein the reflective particle is barium sulfate.

59. The solar radiation reflective fabric of claim 58, wherein the barium sulfate has volume concentration of the reflective fiber of at least 5%.

60. The solar radiation reflective fabric of claim 59, wherein a volume concentration of the barium sulfate in the reflective fiber is no more than 50%.

61. The solar radiation reflective fabric of claim 59, wherein a volume concentration of the barium sulfate in the reflective fiber is no more than 25%.

62. The solar radiation reflective fabric of claim 59, wherein the barium sulfate has a size dimension of between 0.5pm and 5pm.

63. A method keeping a person cool by reflecting solar infrared radiation, said method comprising: a) providing the solar radiation reflective fabric as described in any of the previous claims; and34 b) positioning the solar radiation reflective fabric between a source (SUN) of said solar infrared radiation and said person.

64. The method of claim 63, wherein the solar radiation reflective fabric is configured as a garment and wherein the method further comprises donning the garment on said person.

65. The method of claim 64, wherein the garment is a shirt.

66. The method of claim 64, wherein the garment is a pant.

67. The method of claim 64, wherein the garment is a hat.

68. The method of claim 64, wherein the garment is a vest.

69. The method of claim 64, wherein the garment is coat.

70. The method of claim 63, wherein the solar radiation reflective fabric is configured as a sunshade.

71. The method of claim 63, wherein the solar radiation reflective fabric is configured as a umbrella.

72. The method of claim 63, wherein the solar radiation reflective fabric is configured as a temporary structure.

73. The method of claim 72, wherein the temporary structure is a tent.

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