US20150203995A1

US20150203995A1 - Antistatic Fabric Containing Polyetherimide Filaments

Info

Publication number: US20150203995A1
Application number: US14/602,788
Authority: US
Inventors: Edward Keith Adams; Dale Arnold; Steve Webb; Richard Simonson
Original assignee: International Textile Group Inc
Current assignee: Elevate Textiles Inc
Priority date: 2014-01-22
Filing date: 2015-01-22
Publication date: 2015-07-23

Abstract

The present disclosure is directed to a woven fabric comprising filament yarns. The filament yarns may be comprised of a polyetherimide polymer. The woven fabric may provide flame resistance as well as static/anti-static control. The woven fabric can be employed to provide garments, such as protective garments for a cleanroom.

Description

RELATED APPLICATIONS

The present application is based upon and claims priority to U.S. Provisional Patent Application No. 61/930,138, filed on Jan. 22, 2014, which is incorporated herein by reference in its entirety.

BACKGROUND

Various types of garments exist that are designed to protect the wearer in the environment in which the garment is worn. In certain environments, for instance, the garments are designed to provide protection from heat and flame so as to prevent burn injuries. In other environments, for instance, the protective garments are designed to provide protection from electrostatic discharge so as to prevent the sudden flow of electricity between two electrically charged objects.
In addition, various types of garments are also designed to protect the environment in which they are worn. For instance, in certain environments, the garments are designed to reduce or inhibit the amount of particles that are released from the garment.
Such protective garments can be worn by industrial workers, pilots, rescue personnel, and military personnel. These garments should be as light as possible, strong, flexible, and should encumber the wearer as little as possible. In addition, these garments may also be flame resistant and provide static/anti-static control.
One such type of garment utilized by industrial workers is a cleanroom garment. Cleanroom garments are intended to provide the wearer with static/anti-static control from electrostatic discharge but are also designed to be comfortable to wear. These garments are also designed to inhibit or reduce the release of particles from the garment. In addition, these garments may also be designed to exhibit flame resistance.
These garments have bene produced from various types of fabrics. In the past, fabrics providing static control have been produced from a variety of different materials. For instance, U.S. Pat. No. 6,675,838, which is incorporated herein by reference in its entirety, discloses a fabric comprising non-conductive polypropylene tapes and conductive staple fibers. U.S. Patent Application Publication No. 2006/0272070, which is incorporated herein by reference in its entirety, discloses a cleanroom overall made from flash spun polyester, twill woven fabric from polyester filaments, and laminated fabrics. In addition, aramid polymers and fibers have also been used to produce various garments.
However, polyester and polyolefin fabrics may present some disadvantages and drawbacks. For instance, the fabrics and corresponding garments may not provide flame resistance. In particular, they may not inherently provide flame resistance without the application of a flame retardant. In addition, fabrics and corresponding garments may also drip from melting when exposed to a flame or heat.
Although aramids have been used to produce garments, they also present some disadvantages and drawbacks. For example, the fabrics and corresponding garments tend to be relatively heavy, may not be water resistant, and may not be wind resistant. The fabrics and garments also may not have favorable moisture management properties for many applications. In addition, they may be difficult to dye and/or print, thus making it difficult to apply patterns. Another drawback to the use of aramids is that they are generally produced in staple form and spun into yarns. Spun yarns generally take up greater volume or space at the same weight per unit length as filament yarns. Thus, fabrics made from spun yarns may not provide the same wind resistance protection and water resistance protection as fabrics made from filaments.
In view of the above, a need currently exists for a fabric and a garment that alleviates the disadvantages and drawbacks of current products. In particular, a need exists for a fabric and a garment that is lightweight, has excellent flame resistance properties, and provides excellent static/anti-static control.

SUMMARY

In general, the present disclosure is directed to a woven fabric comprising a first yarn comprising a polyetherimide filament fiber. The polyetherimide polymer is present in the fabric in an amount of greater than 10 wt %. The first yarn may be comprised of a multifilament yarn comprising from about 5 to about 75 filament fibers. The first yarn may have a denier rating of from about 10 to about 1000.
The polyetherimide polymer may have a density of from about 1.2 g/cm³to about 1.5 g/cm³. The polyetherimide polymer may have a molecular weight of from about 10,000 g/mol to about 150,000 g/mol.
In one embodiment, the fabric may further comprise a second yarn comprising a filament fiber not present in the first yarn. The second yarn may be present in the fabric in an amount of from about 0.1 wt. % to about 10 wt. %. The second yarn may be a carbon fiber. In one embodiment, the second yarn may be a bicomponent carbon fiber. The bicomponent fiber may be a polyester/carbon bicomponent fiber or a nylon/carbon bicomponent fiber. The second yarn may also further comprise a polyetherimide filament fiber.
The first yarn may be present in the fabric as a warp yarn and as fill yarn. When present, the second yarn may also be present in the fabric as warp yarn and/or a fill yarn. The woven fabric may be presented as a ripstop weave, a twill weave, a plain weave, an oxford weave, and a basket weave.
The fabric may exhibit a static decay of less than about 2 seconds when measured according to FTM 4046. The fabric may exhibit a surface resistivity of from about 1×10⁵ohms/square to about 1×10¹²ohms/square when measured according to AATCC76. The fabric may exhibit a char length of less than about 6 inches in at least one direction when tested according to ASTM Test D6413. The fabric may exhibit a particle emission rate of less than 12,000 particles/minutes when measuring particles having a size of 0.5 um and greater according to IEST RP CC0003.4.
In one embodiment, the fabric may be substantially free of a polyimide such as an aramid, such as a meta-aramid or a para-aramid. In one embodiment, the fabric may be substantially free of a spun yarn and/or staple fiber.
In one embodiment, the woven fabric may be used in a garment. For instance, the garment may be a cleanroom garment.
Other features and aspects of the present disclosure are discussed in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1A is an enlarged view of a fabric made in accordance with the present disclosure;

FIG. 1B is a top view of a fabric made in accordance with the present disclosure;

FIG. 2 is a perspective view of one embodiment of a cleanroom garment made in accordance with the present disclosure; and

FIGS. 3A-3D are perspective views of other embodiments of cleanroom garments made in accordance with the present disclosure.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations.
In general, the present disclosure is directed to a woven fabric that may provide heat and flame resistance as well as static/anti-static control to a wearer. For instance, the woven fabric may be employed in a garment. In one embodiment, the garment may be flame resistant and protect a wearer from exposure to fire. In another embodiment, the garment may provide static/anti-static control and prevent or inhibit electrostatic discharge. In an even further embodiment, the garment may provide both heat and flame resistance and static/anti-static control.
According to the present disclosure, the woven fabrics are comprised of first yarns. In one embodiment, the first yarns of the fabric may contain filament fibers or yarns. In general, filament yarns are referred to as continuous or near continuous fibers. The filament yarns may be made from flame resistant materials such as inherently flame resistant materials. For instance, in one embodiment, the filament yarns may be made primarily from inherently flame resistant materials.
In general, as indicated above, the first yarns of the fabric may be comprised of filament fibers. These filament fibers may be primarily comprised of synthetic materials. For instance, in one embodiment, the filament fibers may be made primarily from a polyetherimide polymer to provide a polyetherimide filament fiber. For instance, in one embodiment, the filament fibers of the first yarn may be made only from a polyetherimide polymer.
In general, polyetherimide polymers have both polyimide units and polyether units in the polymer backbone. Any polyetherimide known in the art may be utilized according to the present disclosure. In addition, the polyetherimide can be prepared by any method well known in the art. For example, various polyetherimides and methods of syntheses are disclosed in U.S. Pat. No. 6,150,473 to Brown et al. and U.S. Pat. No. 6,403,684 to Jin et al., which are incorporated by reference in their entirety.
In one embodiment, the polyetherimide polymer may have the following chemical structure:
wherein n is the number of repeating monomer units and is greater than 1. In one embodiment, n may be from 10 to 1000, such as from 10 to 500. Polyetherimide polymers are generally available under the tradename ULTEM® by SABIC. The present inventors have discovered that when a polyetherimide filament fiber is used to produce the fabrics and garments, not only do the fabrics and garments exhibit increased strength but they also provide excellent flame resistant properties and static/anti-static control.
In one embodiment, the polyetherimide polymer used to produce the filament fibers may be an unfilled polyetherimide polymer. For instance, the polymer may be substantially free of any reinforcing fibers such as glass fibers. For instance, the polyetherimide polymer may contain less than 0.5 wt. %, such as less than 0.1 wt. %, such as less than 0.01 wt. % of reinforcing fibers such as glass fibers. In one embodiment, the polyetherimide polymer may not contain any reinforcing fibers such as glass fibers.
In addition, the polyetherimide polymer and the filament fibers produced from the polymer that are contained in the fabric and garment may be substantially amorphous. For instance, these filament fibers may have a crystallinity of less than about 40%, such as less than about 20%, such as less than about 15%, such as less than about 10%. The crystallinity may be measured by any method known in the art, such as differential scanning calorimetry or X-ray diffraction.
The polyetherimide polymer of the present disclosure may have a high strength and modulus as well as exhibit excellent mechanical, thermal, and electrical properties. The polyetherimide polymer may exhibit stability over a wide range of temperatures. For instance, the polyetherimide polymer may have excellent high heat resistance such that the polymer exhibits stable properties at elevated temperatures.
The polyetherimide polymer may have a molecular weight of greater than about 5,000 g/mol, such as greater than about 10,000 g/mol, such as greater than about 20,000 g/mol, such as greater than about 40000 g/mol and less than about 200,000 g/mol, such as less than about 100,000 g/mol, such as less than about 75,000 g/mol as measured by gel permeation chromatography using a polystyrene standard.
The polyetherimide polymer may have a glass transition temperature (T_g) of greater than about 180° C., such as greater than about 200° C., such as greater than about 210° C. and less than about 300° C., such as less than about 250° C., such as less than about 230° C., such as less than about 220° C. The glass transition temperature may be measured in accordance with any standard known in the art, such as ASTM 03418.
The polyetherimide polymer may have a density of greater than about 1.1 g/cm³, such as greater than about 1.2 g/cm³, such as greater than about 1.3 g/cm³and less than about 1.6 g/cm³, such as less than about 1.5 g/cm³, such as less than about 1.4 g/cm³, such as less than about 1.3 g/cm³when measured at 25° C.
The polyetherimide polymer may have a tensile strength of greater than about 50 MPa, such as greater than about 75 MPa, such as greater than about 100 MPa and less than about 500 MPa, such as less than about 250 MPa, such as less than about 200 MPa, such as less than about 150 MPa when measured according to ISO R527.
In one embodiment, the polyetherimide filament fibers may be utilized to produce filament yarns. In one embodiment, the filament yarns may be monofilament yarns such as an individual polyetherimide filament fiber or yarn. In another embodiment, the filament yarns may be multifilament yarns. For instance, individual filament fibers may be twisted together to form the multifilament yarns. In one embodiment, the multifilament yarns may comprise at least about 5, such as at least about 6, such as at least about 15, such as at least about 25, such as at least about 30, such as at least about 35 filament fibers, such as polyetherimide filament fibers, and generally less than about 80, such as less than about 75, such as less than about 60, such as less than about 50, such as less than about 40 filament fibers, such as polyetherimide filament fibers.
In one embodiment, the first yarns may comprise multifilament yarns made primarily from polyetherimide filament fibers such that the first yarns and/or the multifilament yarns are comprised of at least 15 wt. %, such as at least 25 wt. %, such as at least 50 wt. %, such as at least 75 wt %, such as at least 90 wt. %, such as at least 95 wt. % of polyetherimide filament fibers. In one embodiment, the first yarns may comprise multifilament yarns comprising 100 wt. % of polyetherimide filament fibers.
The use of multifilament polyetherimide yarns has been found to provide numerous advantages and benefits. Although polyetherimide filaments are known to have good strength characteristics, the increase in strength of the fabric when using the polyetherimide filament yarns is unexpectedly high in comparison to similar fabrics containing other types of filament yarns. While the fabric may be stronger than previous fabrics, the flame resistance properties and the static control of the fabric may also be significantly enhanced.
In addition, it was discovered that when using multifilament yarns made from polyetherimide filaments, the amount of twists placed into the yarn in order to weave the yarn may be minimized. In accordance with the present disclosure, the polyetherimide multifilament yarns may have a minimal amount of twists which not only simplifies the manufacturing process and saves labor costs, but also may enhance the fire resistance properties, or other various properties, of the fabric. For example, filament yarns can be twisted from seven twists per inch, such as from five twists per inch, such as from four twists per inch to two twists per inch, such as three twists per inch. In one embodiment, the filament yarns may be twisted from three twists per inch to five twists per inch.
Filament yarns may generally be used in high constructions to produce a fabric having good wind resistance and water resistance properties. Filament yarns may also produce a fabric that is more breathable especially when compared to products produced with flame resistant coatings. In addition, when using filament yarns, the yarns may be textured. For example, the yarns may be air jet textured. In one embodiment, the yarns may be utilized without any texturing resulting in a direct use after formation.
In addition, the first yarns used to produce the fabric and garment may be monofilament yarns or multifilament yarns. Each yarn may comprise a blend of fibers or may contain a single fiber type. For instance, in one embodiment, the fabric may contain multifilament yarns comprised of blended fibers such as a first filament fiber and a second filament fiber. In another embodiment, as indicated above, the fabric may contain multifilament yarns comprised of only one fiber or filament type.
In one embodiment, the first yarns such as the first filament yarns may include, in addition to the polyetherimide filament fibers, a second filament fiber. The second filament fiber may also be a flame resistant material such as an inherently flame resistant material. For instance, the second filament fiber may be an aramid fiber, such as a para-aramid fiber, a phenylenebenzobismazole fiber, a polybenzimidazole fiber, and the like. The second filament fiber may be present in the fabric and/or the multifilament yarns comprising the polyetherimide filament fibers in an amount of less than about 5 wt. %, such as less than about 2.5 wt. %, such as less than about 1.0 wt. %, such as less than about 0.5 wt %, such as less than about 0.1 wt. %, such as 0 wt. %. In one embodiment, the multifilament yarns comprising the polyetherimide filament fibers may be substantially free of a second filament fiber wherein the second filament fibers are present at about 0 wt. %.
In one embodiment, the fabric and garment may not contain a polyamide polymer or fiber such as an aramid polymer or fiber. For instance, the fabric and garment may contain an aramid in an amount of less than about 1 wt. %, such as less than about 0.5 wt. %, such as less than about 0.1 wt. %, such as less than about 0.05 wt. %, such as 0 wt. %.
The filament yarns, such as the polyetherimide polymer and/or filament yarns, may be present in the fabric in an amount of greater than 10 wt %, such as greater than 15 wt. %, such as greater than 25 wt. %, such as greater than 50 wt. %, such as greater than 75 wt. %, such as greater than 80 wt. %, such as greater than 90 wt. %, such as greater than 95 wt. %, such as greater than 96 wt %, such as greater than 97 wt. %. In one embodiment, they may be present in an amount of less than 100 wt. %, such as less than 99 wt. %. In one embodiment, the fabric may be comprised of 100% polyetherimide polymer and/or polyetherimide filament yarns.
The size of the first filament yarns such as the polyetherimide multifilament yarns used to form the fabric and the basis weight of the fabric can vary dramatically depending upon the particular application and the desired result. As used herein, the size of a yarn refers to its weight per unit length. For filament yarns, size is measured in denier, while for spun yarns size is measured as yarn count. As used herein, a larger sized yarn is generally coarser while a smaller sized yarn is finer. In general, the filament yarns may have a denier of greater than about 10, such as greater than about 100, such as greater than about 150, such as greater than about 175 and generally less than about 1000, such as less than about 900, such as less than about 500, such as less than about 250, such as less than about 225.
In addition, the fabric and/or garment produced therefrom may be substantially free of spun yarns. For instance, spun yarns may be present in an amount of less than about 1 wt. %, such as less than about 0.5 wt. %, such as less than about 0.1 wt. %, such as less than about 0.05 wt. %. In one embodiment, the fabric may be substantially free of any spun yarns wherein the spun yarns are present at about 0 wt. %. For instance, in one embodiment, the fabric may not contain any spun yarns. In addition, the fabric and/or garment produced therefrom may be substantially free of staple fibers. For instance, staple fibers may be present in an amount of less than about 1 wt. %, such as less than about 0.5 wt. %, such as less than about 0.1 wt. %, such as less than about 0.05 wt. %. In one embodiment, the fabric may be substantially free of any staple fibers wherein the staple fibers are present at about 0 wt %. For instance, in one embodiment, the fabric may not contain any staple fibers. For instance, spun yarns and/or staple fibers may increase the particle matter, such as lint, that is released from the fabric or garment.
Not to be limited by theory, filament yarns are generally prepared from long, continuous filament fibers. As indicated above, filament yarns may be monofilament yarns or multifilament yarns. Not to be limited by theory, generally, spun yarns are prepared by twisting or bonding short, staple fibers together to make a cohesive thread or yarn. The short, staple fibers are generally spun to produce the yarn.
In one embodiment, the body yarns, such as the yarns that form the body of the fabric, may be comprised of the first yarns, such as the filament yarns such as the polyetherimide filament yarns. In one embodiment, the body yarns may be primarily comprised of the first yarns such as the polyetherimide filament yarns.
The fibers, such as the filament fibers, used to produce the fabric are constructed into yarns that are then woven or knitted together. Woven fabrics made in accordance with the present disclosure generally include a warp direction and a fill direction wherein a plurality of warp yarns are interwoven with a plurality of fill yarns.
In accordance with the present disclosure, at least one of the warp yarns and/or at least one of the fill yarns is comprised of first filament yarns such as multifilament yarns comprising polyetherimide filament fibers. Placing the filament yarns in the warp direction or the fill direction may depend upon the equipment used to produce the fabric and the type of weave. In one embodiment, the warp yarns and the fill yarns are comprised of filament yarns.
As indicated above, the first yarns may comprise the body yarns of the fabric. In one embodiment, the second yarns are woven within the body yarns. The second yarns are provided depending upon the desired properties. For instance, in one embodiment, a greater number of body yarns may be provided between consecutive second yarns in a warp direction, in a fill direction, or in both a warp and fill direction.
In general, various different weave patterns may be used to produce the fabric. For instance, a twill weave, a plain weave, a ripstop weave, a herringbone weave, an oxford weave, a basket weave, or any other suitable weave may be used. In one particular embodiment, the fabric may have a ripstop weave. In another particular embodiment, the fabric may have a twill weave. In another embodiment, the fabric may have a plain weave.
In general, a ripstop weave is utilized to provide a reinforcing technique to prevent or inhibit the tearing and/or ripping of fabric. For instance, the ripstop weave may prevent the expansion or elongation of an existing tear or rip in the fabric. The ripstop weave may provide such advantages while also retaining lightweight characteristics. In general a twill weave is formed wherein fill or weft threads or yarns are woven over and under two or more warp yarns thereby producing a diagonal pattern.
In one embodiment, the fabric and garment produced therefrom may be comprised of first yarns and second yarns. The first yarn may be the yarns as described above. The second yarns may be comprised of reinforcement yarns or threads different from the first yarns. For instance, in one embodiment, the second yarns may be formed from a different material than the first yarns.
In general, without intending to be limited by theory, in one embodiment, the second yarns may provide the fabric and garment with ripstop characteristics. For instance, they may provide resistant against tearing and/or ripping. In another embodiment, the second yarns may provide the fabric and garment with static/anti-static control.
In one embodiment, during weaving, second yarns may be interwoven at regular or irregular intervals in a pattern. For instance, the ripstop weave fabric may be produced by weaving the second yarns throughout the yarns in an interlocking pattern. For instance, as shown in FIGS. 1A and 1B, the yarns or threads 200 may be woven in a crosshatch pattern or a grid-like or checkerboard pattern in the base material 206 of the fabric. For instance, the pattern may form a plurality of cells 208 such as squares and/or rectangles in the fabric. Accordingly, a rip or tear may be contained within a respective cell of the ripstop fabric.
In one embodiment, the second yarns may be present in the warp direction only. In another embodiment, the second yarns may be present in the fill direction only. In another embodiment, as illustrated in FIGS. 1A and B, the second yarns may be present in the warp direction and the fill direction.
Therefore, the second yarns may also be employed in a twill weave or a plain weave. For instance, they may be present in the warp direction, the fill direction, or both the warp direction and the fill direction.
The second yarns may be incorporated into the fabric in any manner and configuration to obtain the desired properties. In one embodiment, the second yarns are interwoven such that at least one yarn is present at least every 20 ends, such as every 30 ends, such as every 40 ends. In one embodiment, the second yarns may be present at least every 20 picks, such as every 30 picks, such as every 40 picks. In one embodiment, the second yarns may be present at least every 20 ends and picks, such as every 30 ends and picks, such as every 40 ends and picks. In one embodiment, the second yarns may be provided in the fabric such that they are present at least every 20 filament yarns, such as every 30 filament yarns, such as every 40 filament yarns such as polyetherimide filament yarns.
When more than one second yarn is woven next to or adjacent to one another in the same weaving direction, they may have the same weaving pattern or different weaving patterns. For instance, depending upon the direction the second yarns are woven, they may cross over or skip the same warp or weft yarn or different warp or weft yarns such as alternating warp or weft yarns.
As provided in FIGS. 1A and 1B, the second yarns in the warp direction may be orthogonal to the yarns or threads in the fill direction. As such, the pattern may form a plurality of cells 208 such as squares and/or rectangles in the fabric. However, it should be understood that the second yarns may be interwoven into the fabric in any pattern known in the art.
In general, the second yarns such as the reinforcement yarns or threads may be any typically used in the art. For instance, in one embodiment, they may be any of used for forming ripstop weave patterns and/or any that provide static-anti-static control.
In one embodiment, the second yarns such as the reinforcement yarns or threads may also be comprised of a filament fiber. The filament fiber may be comprised of a synthetic fiber. In one embodiment, the second yarns may be formed from a different material than the first yarns.
In one embodiment, the second yarns such as the reinforcement yarns or threads may be a carbon fiber. In a further embodiment, the carbon fiber may be a bicomponent carbon fiber. For instance, the second yarns may be comprised of a core/sheath bicomponent carbon fiber. In one embodiment, the core/sheath bicomponent fiber may be comprised of a polyester/carbon bicomponent filament fiber. For instance, the carbon may provide the sheath component while the polyester may provide the core component of the bicomponent fiber. In another embodiment, the core-sheath bicomponent fiber may be comprised of a nylon/carbon bicomponent filament fiber. For instance, the carbon may provide the sheath component while the nylon may provide the core component of the bicomponent fiber.
The bicomponent fibers may be produced by utilizing an extrusion process such as a co-extrusion process. For instance, the core component may be extruded contemporaneously as the sheath component is extruded to surround the core component. Alternatively, the sheath component may be extruded onto the core component after the core component has been extruded. In one embodiment, the bicomponent fibers may be concentric core/sheath bicomponent fibers. In an alternative embodiment, the bicomponent fibers may be eccentric core/sheath bicomponent fibers. The bicomponent fibers utilized may be those that are commercially available and produced using any method known in the art.
However, it should be understood that the present disclosure is not limited to bicomponent fibers and that any filament fiber known in the art may be employed. For instance, any carbon fiber or poly/carbon fiber known in the art may be employed within the fabric.
In one embodiment, the second yarns such as the reinforcement yarns or threads may be comprised of more than one fiber such as more than one filament fiber. For instance, the second yarns may be interwoven as a bundle comprising two or more filament fibers. In one embodiment, the second yarns may be comprised of at least two individual fibers or ends. For instance, the second yarns may be comprised of from one to up to two, such as up to three, such as up to five, such as up to ten individual filament fibers or ends.
For instance, in one embodiment, the second yarns may be comprised of a yarn different from the first yarn in addition to a polyetherimide fiber, such as a polyetherimide filament fiber. For instance, one end of the polyetherimide filament fiber may be twisted with one end of a second yarn filament fiber different from the first yarn, such as a reinforcement thread such as a carbon fiber. In another embodiment, the second yarn may also be comprised of more than one polyetherimide filament fiber. For instance, one end of the polyetherimide filament fiber may be twisted with one end of a second yarn filament fiber different from the first yarn, such as a reinforcement thread such as carbon fiber, and one end of another additional polyetherimide filament fiber may be twisted with one end of the fiber comprising the polyetherimide filament fiber and the second yarn filament fiber. As such, the second yarn may be comprised of two ends of a polyetherimide filament fiber and a filament fiber different from the polyetherimide filament fiber.
Accordingly, the second yarns may also be monofilament yarns or multifilament yarns.
When preparing the second yarns comprising more than one filament fiber, the fibers may be twisted utilizing any method known in the art. For instance, the fibers may be twisted utilizing a hollow spindle process.
In one embodiment, the second yarns are interwoven throughout the base polyetherimide material in an interlocking pattern. The present inventors have discovered that by weaving the second yarns with the polyetherimide filament yarns, a fabric can be produced that provides adequate static dissipation and/or resistance to tearing.
In one embodiment, the first yarns such as the polyetherimide filament yarns may occupy a greater surface area than the second yarns such as the reinforcement yarns or threads comprising the polyester/carbon bicomponent fibers. In one embodiment, when second yarns are present, the first yarns such as the polyetherimide filament yarns may comprise at least 25%, such as at least 50%, such as at least 60%, such as at least 70%, such as at least 80%, such as at least 90%, such as at least 95% and generally less than about 100% of the surface area of at least one side of the fabric. In another embodiment, when second yarns are present, the first yarns such as the polyetherimide filament yarns may comprise at least 25%, such as at least 50%, such as at least 60%, such as at least 70%, such as at least 80%, such as at least 90%, such as at least 95% and generally less than about 100% of the surface area of both sides of the fabric.
In another embodiment, the first yarns such as the polyetherimide filament yarns may comprise 100% of the surface area of at least one side of the fabric. In another embodiment, the first yarns such as the polyetherimide filament yarns may comprise 100% of the surface area of both sides of the fabric
In one embodiment, the second yarns such as the reinforcement yarns or threads may have a denier rating of at least 20 denier, such as at least 30 denier, such as at least 40 denier, such as at least 50 denier and generally less than about 200 denier, such as less than about 100 denier, such as less than about 80 denier, such as less than about 70 denier, such as less than about 60 denier.
As indicated above, the second yarns such as the reinforcement yarn or thread may comprise a bicomponent fiber such as a core/sheath bicomponent fiber having a core component and a sheath component. The core component may be present in the fabric in an amount of greater than about 0.1 wt. %, such as greater than about 0.5 wt. %, such as greater than about 1 wt. %, such as greater than about 1.5 wt. % and less than about 5 wt. %, such as less than about 4 wt. %, such as less than about 3 wt. %, such as less than about 2.5 wt. %, such as less than about 2 wt. %. The sheath component may be present in the fabric in an amount of greater than about 0.1 wt. %, such as greater than about 0.2 wt. %, such as greater than about 0.4 wt. %, such as greater than about 0.75 wt. %, such as greater than about 1 wt %, such as greater than about 1.5 wt. % and less than about 5 wt. %, such as less than about 4 wt. %, such as less than about 3 wt. %, such as less than about 2 wt. %, such as less than about 1.5 wt. %, such as less than about 1.0 wt. %
The bicomponent fibers may be present in fabric and garment in an amount of greater than about 0.1 wt. %, such as greater than about 0.5 wt %, such as greater than about 1 wt. %, such as greater than about 2 wt. % and less than about 10 wt. %, such as less than about 5 wt. %, such as less than about 4 wt. %, such as less than about 3 wt. %.
The second yarns, when present, such as the reinforcement yarns or threads may be present in the fabric and garment in an amount of greater than about 0.1 wt. %, such as greater than about 0.5 wt. %, such as greater than about 1 wt. %, such as greater than about 2 wt. % and less than about 10 wt. %, such as less than about 5 wt. %, such as less than about 4 wt. %, such as less than about 3 wt. %.
In one embodiment, the fabric and garment may be substantially free of any reinforcement yarns or threads or second yarns. For instance, the reinforcement yarns or threads or second yarns may be present in the garment or fabric in an amount of less than about 1 wt. %, such as less than about 0.5 wt. %, such as less than about 0.1 wt. %, such as less than about 0.05 wt. %, such as 0 wt. %. For instance, the fabric or garment may consist of polyetherimide filament fibers.
The weave density of the fabric may generally vary with the yarn sizes. For instance, a fabric produced from 20 denier yarns may have approximately 300 to about 350 ends and from about 200 to about 250 picks. A product produced from 50 denier yarns, on the other hand, may have from about 150 to about 200 ends and from about 100 to about 130 picks. A fabric produced from 70 denier yarns, on the other hand, may have from about 140 to about 160 ends and from about 80 to about 90 picks. A fabric produced from 150 denier yarns, on the other hand, may have from about 100 to about 120 ends and from about 60 to about 80 picks. A fabric made from 200 denier yarns may have from about 30 to about 90 ends, such as from about 50 to about 90 ends and from about 30 to about 90 picks, such as from about 40 to about 70 picks. A fabric produced from 500 denier yarns, on the other hand, may have from about 55 to about 65 ends and from about 45 to about 55 picks. In still another embodiment, a fabric produced from 1000 denier yarns may have from about 30 to about 40 ends and from about 30 to about 35 picks.
The fabric of the present disclosure may have a weave density in the warp direction of greater than about 30 ends per inch, such as greater than about 40 ends per inch, such as greater than about 50 ends per inch, such as greater than about 60 ends per inch, such as greater than about 65 ends per inch and less than about 100 ends per inch, such as less than about 90 ends per inch, such as less than about 80 ends per inch, such as less than about 70 ends per inch, such as less than about 65 ends per inch.
The fabric of the present disclosure may have a weave density in the fill or weft direction of greater than about 30 picks per inch, such as greater than about 40 picks per inch, such as greater than about 50 picks per inch, such as greater than about 60 picks per inch, such as greater than about 65 picks per inch and less than about 100 picks per inch, such as less than about 90 picks per inch, such as less than about 80 picks per inch, such as less than about 70 picks per inch, such as less than about 65 picks per inch.
Once the fabric is constructed, the fabric may be treated with various coatings and finishes as may be desired. The coatings or finishes, if applied, should be applied to the fabric and garment without compromising the flame resistant properties or the static/anti-static control properties of the fabric. In one embodiment, the fabric and garment may not contain any finishes or coatings. For instance, after production of the fibers and yarns, the yarns may be woven to produce the fabric and garment. The fabric and garment may then be directly used without application of a further coating or finish.
In one embodiment, for instance, the fabric may be treated with a durable water resistant treatment which may comprise, for instance, a fluoropolymer or a fluorine containing material, such as an oil, fluorosilicone oil, etc. In another embodiment, the fabric may be treated with a flame resistant polymer composition such as a polyurethane, an aromatic compound containing halogen, antimony oxide, etc. In another embodiment, the fabric may be treated with an anti-odor agent that may comprise metal ions, such as silver ions.
In addition, the fabric of the present disclosure may be dyed or printed with any suitable color. Fabrics made according to the present disclosure may be dyed and/or printed prior to or after being formed into a garment. For instance, the polyetherimide fibers present within the fabric may be jet dyed and then incorporated into a fabric. In one embodiment, the fibers may be solution dyed (producer coloring) and incorporated into the fabric. The fabric may also be printed using a pattern. Any suitable dye and/or pigment for application to a polyetherimide fabric may be used.
In one particular embodiment, the fabric may be woven or knitted and then dyed a particular base shade. Once dyed, any suitable pattern may then be printed on the fabric. For instance, in one embodiment, a pattern may be printed onto the fabric using a rotary screen printing method. Once the pattern is applied to the fabric, the dye applied to the fabric during the printing process may be developed.
In one embodiment, a camouflage pattern may be applied to the fabric, especially when the fabric is to be used in constructing military garments and/or hunting garments. A camouflage pattern, for instance, is intended to provide concealment properties to the wearer in both the human visible light range and the near infrared range. The camouflage pattern, for instance, may include at least 4 colors using dyes that in combination produce a range of reflectance values similar to that of the background environment in which the garment is to be used.
The filament yarns are constructed from materials and woven together in a manner that produces a fabric having excellent thermal and physical properties. For instance, the fabric has excellent strength properties in combination with excellent tactile qualities. In particular, the fabric also has a soft hand, meaning that the fabric is flexible. Of particular advantage, the above characteristics and properties are obtained at relatively low fabric weights. Consequently, garments made from the above described fabric not only provide excellent thermal protection and/or static control but are also very comfortable to wear.
In addition, the fabrics of the present disclosure may also be constructed to also have excellent wind and water resistant properties while remaining highly breathable, especially in comparison to fabrics made from aramid fibers. The fabrics may also have better drape properties and surface texture.
The basis weight of fabrics made according to the present disclosure may vary depending upon various factors and the end use application. Of particular advantage, fabrics made according to the present disclosure can have excellent properties at relatively lighter basis weights. In general, the fabric may have a basis weight of at least about 1 osy, such as at least about 2 osy, such as at least about 3 osy, such as at least about 3.5 osy, such as at least about 4 osy and generally less than about 10 osy, such as less than about 9 osy, such as less than about 8 osy, such as less than about 7 osy, such as less than about 6 osy, such as less than about 5 osy, such as less than about 4.5 osy. In particular, it was discovered that fabrics made according to the present disclosure may have a basis weight of from about 2 osy to about 5 osy, while still having many of the physical properties of conventional fabrics having a basis weight of about 7.5 osy or greater.
Fabrics and/or garments made in accordance with the present disclosure exhibit sufficient flame resistant properties and static control so as to protect a wearer from fires and electric arcs. For instance, one test for measuring the flame resistant properties of a fabric is known as the vertical flame test. The vertical flame test has been standardized as the ASTM D-6413 test. The test measures the vertical flame resistance of textiles. In particular, a specimen of a fabric is suspended vertically in a holder. A controlled flame is then impinged on the bottom cut edge of the fabric for 12 seconds. Upon removing the flame at the end of the 12 second period, different characteristics of the fabric are measured. The first characteristic is referred to as “after flame or glow” and represents the number of seconds during which there is a visible flame remaining on the fabric after the controlled flame has been removed. Further, the char length of the fabric can be measured which is the length of fabric destroyed by the flame that will readily tear by application of a standard weight. The third characteristic is any evidence of melting and dripping. In conducting the test, five specimens are tested in both the warp and weft directions and the results are averaged.
The fabric and/or garment of the present disclosure also possess excellent thermal properties. For instance, when tested according to ASTM Test D6413, the fabric and/or garment may have a char length in both the fill and warp direction of less than about 10 inches, such as even less than about 8 inches, such as even less than about 6 inches, such as less than about 4 inches in one direction or in both directions. The char length may be greater than about 0.5 inches, such as greater than about 1 inches. The fabric and/or garment may have an after glow of less than about 7 seconds, such as less than about 5 seconds, such as less than about 2 seconds, such as 0 seconds, and exhibit substantially no dripping. In comparison, similar polyester or nylon fabrics, when subjected to the vertical flame test, typically exhibit a torch-like burn pattern and exhibit char lengths greater than the specimen length (12 inches) and after flames of 10 seconds or greater. The fabrics and also have a tendency to melt and drip during the test. Fabrics and/or garments made in accordance with the present disclosure, however, may be subjected to the vertical flame test without producing any drips.
The fabric may be a Class 1 fabric according to 16 CFR 1610 such that it may exhibit normal flammability and is suitable for use in clothing. According to 16 CFR 1610, the burn time indicates the time from igniting a specimen to the time the flame travels up the specimen breaking the stop thread, generally a cotton sewing thread. When the stop yarn or thread breaks, the stop weight falls and stops the timing device. In general, for a fabric have a plain surface, a Class 1 material is defined as a material having an average burn time of greater than or equal to 3.5 seconds while a Class 3 material is defined as a material having an average burn time of less than 3.5 seconds. For a fabric having a raised surface, a Class 1 material is defined as a material have an average burn time of greater than 7.0 seconds or an average burn time of from 0 to 7 seconds wherein the base fabric has no base burns, a Class 2 material has an average burn time of from 4 to 7 seconds wherein the base fabric has base burns, and a Class 3 material has an average burn time of less than 4.0 seconds wherein the base fabric has base burns.
Fabrics made in accordance with the present disclosure may also display excellent strength properties. For instance, when tested according to ASTM Test D5034, the fabric may have a strength of greater than 20 lbs., such as greater than 30 lbs., such as greater than 50 lbs., such as greater than 75 lbs.
When tested according to ASTM Test D1424, the treated fabric may have a tear strength of greater than about 500 grams, such as greater than about 1000 grams, such as greater than about 1500 grams, such as greater than about 2000 grams, such as greater than about 2500 grams and generally less than about 5000 grams, such as less than about 4000 grams.
In addition, the fabric and/or garment of the present disclosure may employ a static dissipate which attracts static charges. For instance, the carbon fibers, such as the bicomponent carbon fibers, may attract and lower the static charges. According to the present disclosure, the fabric may dissipate static electricity that is generated from fabric to fabric and fabric to surface rubbing or contact and minimize the hazards that may be created by static electricity. For instance, the fabric may provide a barrier between static charges generated on personal clothing and static-sensitive components such that the fabric provides electrostatic dissipation across the garment's entire surface reducing the likelihood of damage from an electrostatic discharge.
The static dissipative properties of a fabric and/or garment may be tested by measuring the surface resistance of a fabric to an electrical flow and the static decay of a charge from the fabric. In addition, these static dissipative properties identified below may even be maintained in low humidity conditions where 100% cotton fabric may not provide as much anti-static protection.
In general, surface resistance is a measurement of the resistance of an electrical flow over or through a medium such as a fabric and/or garment. Generally, the lower the resistivity, the better a charge is dissipated and the greater the electrostatic discharge protection. The surface resistivity may be measured according to AATCC 76 (NFPA099) using a concentric electrode electrical resistance meter and preconditioning the samples at 50% relative humidity and a temperature of 23° C.±2° C. for approximately 24 hours. Generally, 100 volts are supplied during the tests.
In one embodiment, the fabric and/or garment has a surface resistivity of less than 1×10¹²ohms/square, such as less than 1×10¹¹ohms/square, such as less than 1×10¹⁰ohms/square, such as less than 1×10⁹ohms/square, such as less than 1×10⁸ohms/square, such as less than about 1×10⁷ohms/square, such as less than about 1×10⁵ohms/square and generally greater than about 1×10²ohms/square, such as greater than about 1×10⁵ohms/square, such as greater than about 1×10⁶ohms/square. In one embodiment, the fabric has a surface resistivity of less than 1×10¹¹ohms/square.
In general, static decay is the speed of a charge draining of materials such that it provides a measure of how long it takes static buildup to drain into the ground. Generally, the faster the decay time, the better the drain and/or dissipation.
The static charge decay test may conform to Federal Test Standard 191A, Method 5931. The test fabric is supported between 2 electrodes then exposed to a 5 kV source. The test conditions are 21° C. and 20% relative humidity. Generally, it may be required that the fabric accepts a minimum of 3 kV and be capable of discharging 10% of this voltage within ½ of a second at the time when the electrodes are grounded.
In one embodiment, the fabric and/or garment may be capable of accepting a voltage of greater than 3 kV even after 25 launderings, such as 50 launderings, such as even 100 launderings. In one embodiment, the fabric and/or garment may be capable of discharging 10% of this voltage in less than % of a second, such as less than 0.25 seconds, such as less than 0.1 seconds, such as less than 0.05 seconds. In one embodiment, the fabric and/or garment may be capable of discharging 10% of the voltage in the above mentioned times even after 25 launderings, such as after 50 launderings, such as after 100 launderings.
A standard laundry cycle, for instance, is described in U.S. Pat. No. 6,880,184, which is incorporated herein by reference. The laundry method is test AATCC 135,(1),IV,A,(1)-normal wash cycle, 120° F., tumble dry cotton sturdy cycle. During a laundry cycle, the fabric and/or garment is washed in an automatic washer, followed by drying in an automatic dryer.
A commercial laundry cycle may be conducted in accordance with AATCC 96-2001. The parameters include a normal wash at 165° F. with standard detergent and a tumble dry high.
In comparison, general cotton and cotton/polyester blend fabrics require greater than 5 seconds, such as greater than 10 seconds to discharge 10% of the accepted voltage. In addition, after 25 launderings, those cotton/polyester blend fabrics may not be capable of accepting a minimum of 3 kV.
The static decay may also be measured according to FTM 4046 (NFPA-99) with a charge of 5000-500 volts at 50% relative humidity and a temperature of 23° C.±2° C. The specimen is initially charged with 5000 volts and then the time is measured by which the charged electrostatic potential attenuates to 500 volts. Using the aforementioned test, the fabric and/or garment may have a static decay of less than about 3 seconds, such as less than about 2 seconds, such as less than about 1 second, such as less than about 0.5 seconds, such as less than about 0.1 seconds and generally greater than about 0.001 seconds, such as greater than about 0.01 seconds, such as greater than about 0.1 seconds.
In addition, the fabrics and garments of the present disclosure may also be tested according to the Helmke Drum Test in accordance with IEST RP CC0003.4. This test provides an indication of the cleanliness based on airborne particles. In general, a size of 0.5 μm and larger may be used as the basis for evaluation. According to the method, the fabric or garment is placed in a stainless steel rotating drum that is open at one end and tumbled to release particulate matter from the fabric or garment. The drum is generally rotated at a rate of 10 rpm. An automatic particle counter, such as a laser particle counter, is utilized to sample the air within the drum to determine the particle density level of the air. In general, the test is conducted for a duration of 10 minutes and particle counts are recorded at one minute intervals. This density level is then utilized to determine a relative class for the particular type of garment. For instance, a Category I garment will exhibit a particle emission rate of less than 1,200 particles/minute, a Category II garment will exhibit a particle emission rate of from 1,200-12,000 particles/minute, and a Category III garment will exhibit a particle emission rate of from 12,000-120,000 particles/minute. The above mentioned particle emission rates are provided based on a particle size of 0.5 μm and larger. However, according to the test, particle emission rates may be also be conducted according to the test for particles having a particle size of 0.3 μm and larger, a particle size of 1.0 μm and larger, or a particle size of 5.0 μm and larger.
The fabrics and/or garments of the present disclosure may exhibit a particle emission rate of less than 12,000 particles/minute, such as less than 10,000 particles/minute, such as less than 5,000 particles/minute, such as less than 1,200 particles/minute, such as less than 1,000 particles/minute, such as less than 500 particles/minute, such as less than 200 particles/minute and generally greater than 0 particles/minute. In general, Category I garments have the lowest particle shed requirements and are considered the cleanest. The fabrics and/or garments of the present disclosure may be classified as a Category I garment. As such, the fabrics and/or garments are designed to produce a minimum of particles.
When utilized for various cleanrooms, the cleanroom standards can be determined or obtained according to ISO 14644-1. The ISO standard classifies cleanrooms in terms of airborne particle concentrations of particles in the size range of 0.1 to 5 μm. In general, an ISO Class 1 cleanroom is the cleanest environment while an ISO Class 9 cleanroom is the least clean of the ISO cleanroom classes.
Linting can be an important factor for garment selection, especially in particle controlled environments. The garments of the present disclosure may be utilized in environments requiring low-linting properties. For instance, linting refers to the shedding of particles by certain materials. A garment exhibiting high linting sheds more particles than one exhibiting low linting. Thus, by utilizing low-linting garments, the burden is reduced on the particle filtration and/or removal systems of the cleanroom.
As indicated above, in one embodiment, the fabric and/or garment produced therefrom may provide a user with static/anti-static control. In another embodiment, the fabric and/or garment may even be antistatic. For instance, the fabric and/or garment may prevent or inhibit the buildup of static electricity.
The fabrics and/or garments made according to the present disclosure may be lightweight and soft while also providing protection and comfort. The fabrics can be used to produce garments that are breathable. In addition, the garments may also serve as barriers against certain particles, microorganisms, and non-hazardous liquids. In addition, the fabrics and/or garments may also be low-tinting.
As such, the various protective garments may be made in accordance with the present disclosure. The garments may have a shape and size configured to cover at least a portion of a wearer's body. The protective garments include, for instance, footwear, footwear covers, trousers, jackets, coats, labcoats, frocks, shirts, headwear, hoods, bouffants, gloves, aprons, smocks, masks, face veils, and the like. The fabric can also be used to construct one-piece jumpsuits, which may be well suited for use in industrial settings. For instance, the fabric can be used to provide a cleanroom garment. The garment may also be used by personnel working with electrical maintenance, circuitry, and the like. The garments may be used in microelectronics manufacturing, pharmaceutical applications, biotechnology, and the like.
In one embodiment, the fabric may be used to construct a garment worn in a cleanroom. For instance, referring to FIG. 2, one embodiment of a cleanroom garment 100 constructed in accordance with the present disclosure is illustrated. As shown in FIG. 2, the cleanroom garment 100 is a one-piece hooded coverall. However, it should be understood that the clean-room garment may contain multiple pieces. For instance, the coverall may be present without an attached hood. As shown in FIG. 3A-FIG. 3D, the clean-room garment may comprise, respectively, a frock/labcoat 102, a shoe cover 106, a bouffant 110, a hood 114, and the like such as pants, boot covers, gloves, aprons, masks, veils, sleeve covers, etc. In addition, these garments may also include undergarments, such as clothes worn under other clothes. In some cases, these undergarments may include those garments worn next to one's body or skin.
These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.

Claims

1. A woven fabric comprising:

a first yarn comprising a polyetherimide polymer filament fiber, wherein the polyetherimide polymer is present in the fabric in an amount of greater than 10 wt. %.

2. A woven fabric as defined in claim 1, wherein the polyetherimide polymer is present in the fabric in an amount of greater than about 50 wt. %.

3. A woven fabric as defined in claim 1, wherein the first yarn is a multifilament yarn.

4. A woven fabric as defined in claim 3, wherein the multifilament yarn is comprised of from about 5 to about 75 filament fibers.

5. A woven fabric as defined in claim 1, wherein the first yarn has a denier rating of from about 10 to about 1000.

6. A woven fabric as defined in claim 1, wherein the polyetherimide polymer has a density of from about 1.2 g/cm³to about 1.5 g/cm³and a molecular weight of from about 10,000 g/mol to about 150,000 g/mol.

7. A woven fabric as defined in claim 1, wherein the fabric further comprises a second yarn comprising at least one filament fiber not present in the first yarn, the second yarn being present in the fabric in an amount of from about 0.1 wt. % to about 10 wt. %.

8. A woven fabric as defined in claim 7, wherein the second yarn further comprises a polyetherimide filament fiber.

9. A woven fabric as defined in claim 7, wherein the second yarn is woven into the fabric as a bundle comprising from 2 to 10 filament fibers.

10. A woven fabric as defined in claim 7, wherein the second yarn has a denier rating of from about 20 to about 100.

11. A woven fabric as defined in claim 1, wherein the fabric further comprises a carbon fiber.

12. A woven fabric as defined in claim 1, wherein the fabric further comprises a bicomponent fiber.

13. A woven fabric as defined in claim 12, wherein the bicomponent fiber is a polyester/carbon bicomponent fiber.

14. A woven fabric as defined in claim 1, wherein the fabric has a weight of from about 2 osy to about 8 osy.

15. A woven fabric as defined in claim 1, wherein the woven fabric includes a warp yarn and a fill yarn, the warp yarn and the fill yarn comprising the polyetherimide polymer.

16. A woven fabric as defined in claim 7, wherein the second yarn is present in the fabric at least every 40 ends.

17. A woven fabric as defined in claim 1, wherein the woven fabric has a ripstop weave, a twill weave, a plain weave, an oxford weave, or a basket weave.

18. A woven fabric as defined in claim 1, wherein the woven fabric has from about 30 to about 85 ends per inch and from about 30 to about 90 picks per inch.

19. A woven fabric as defined in claim 1, wherein the fabric exhibits a static decay of less than about 2 seconds when measured according to FTM 4046.

20. A woven fabric as defined in claim 1, wherein the fabric exhibits a surface resistivity of from about 1×10⁵ohms/square to about 1×10¹²ohms/square when measured according to AATCC76.

21. A woven fabric as defined in claim 1, wherein the fabric has a char length of less than about 6 inches in at least one direction when tested according to ASTM Test D6413.

22. A woven fabric as defined in claim 1, wherein the fabric exhibits a particle emission rate of less than 12,000 particles/minutes when measuring particles having a size of 0.5 um and greater according to IEST RP CC0003.4.

23. A woven fabric as defined in claim 1, wherein the fabric further comprises a dye or a pigment.

24. A woven fabric as defined in claim 1, wherein the fabric is substantially free of a polyamide.

25. A woven fabric as defined in claim 1, wherein the fabric is substantially free of a spun yarn.

26. A protective garment comprising the woven fabric of claim 1.

27. A protective garment according to claim 26, wherein the garment is a cleanroom garment.