US20070093162A1

US20070093162A1 - Fabric and a method of making the fabric

Info

Publication number: US20070093162A1
Application number: US11/409,113
Authority: US
Inventors: Barry Holcombe; Ian Blanchonette; David Evans; Laurence Staynes; John Rippon; Ronald Denning; Birgit Schaldecker; Petra Kiessling
Original assignee: Gore Enterprise Holdings Inc
Current assignee: WL Gore and Associates Inc
Priority date: 2004-10-22
Filing date: 2006-04-21
Publication date: 2007-04-26
Also published as: EP1802803A4; EP1802803A1; WO2006042375A1; JP2008517178A

Abstract

The present invention is based on the realization that improved wicking of liquid from an inner face to an outer face of a fabric can be achieved by a fabric structure where the inner face of the fabric has a substantially uniform hydrophobicity and where the inner face is formed by hydrophobic yarn that is assembled in a manner that allows the liquid to penetrate between hydrophobic yarn and make contact with hydrophilic yarn that forms at least part of the outer face of the fabric. When liquid penetrates the inner face and makes contact with the hydrophilic yarn, liquid is able to be drawn through the inner face to the outer face of the fabric. Although the hydrophobic and hydrophilic yarns and may be made from any one or a blend of man-made or synthetic fibers, and natural fibers, it is preferred that the yarns and the fully formed fabric be made entirely of cotton fibers. The fabric is suitable for use in a wide range of applications including underwear. Another application involves laminating the fabric to a functional film such as a waterproof and/or windproof breathable membrane to produce functional outerwear garments.

Description

RELATED APPLICATIONS

This application is a continuation-in-part of International Patent Application No. PCT/AU2005/001638, designating the United States, filed on Oct. 21, 2005, which claims the benefit of U.S. Provisional Application No. 60/621,943, filed on Oct. 22, 2004.

FIELD OF THE INVENTION

The present invention relates to a new fabric and a method of making the fabric that is capable of transferring liquid from an inner face to an outer face of the fabric by wicking. According to one particular preferred embodiment of the present invention, the fabric consists entirely of cotton fibers and is suitable for making sports garments or under garments that help keep a person dry and comfortable.

BACKGROUND OF THE INVENTION

Cotton fiber in its raw state is coated by naturally occurring waxes that make it hydrophobic. Once this coating is removed, by scouring for example, the fiber surface is strongly hydrophilic—more so than any non-cellulosic fiber. This high surface energy brings positive benefits, but in some conditions, significant disadvantages.
In low activity conditions where moisture in the clothing microclimate is mostly in the form of vapour, cotton fabrics adjacent to the skin moderate or ‘buffer’ changes in moisture vapour extremely well due to the hygroscopic properties of cotton fibers, hence the widely recognised ‘breathable’ reputation of cotton. As moisture levels rise and liquid sweat is formed, cotton wicks sweat off the skin quickly and easily. However, in conditions where large amounts of sweat are excreted, liquid bridges are formed between the skin and fabric, thereby causing the fabric to stick and drag on the skin during movement, a phenomenon known as “wet cling”. The high surface energy and fine diameter of cotton fibers also causes cotton fabrics to have a high storage capacity for liquids. Cotton fabrics hold more liquid than equivalent fabrics of other fibers when saturated and therefore take significantly longer to dry. As a result, cotton is generally perceived as a relatively “low-tech” product when compared to modern synthetics.
Synthetic polymers typically have relatively low surface energy. In order to improve their wicking performance, they are often treated with hydrophilic finishes of one form or another to increase the fiber surface energy, although they do not reach the same level as cotton. Wet cling is much less of a problem. In some of the more technically-oriented synthetic products, multi-layer structures consisting of fibers of different surface energies and/or different fiber diameters are used to create a wicking gradient between the inner surface and the outer surface of the fabric so that sweat is preferentially transported away from the skin. Moisture transport that occurs preferentially from one face of the fabric to the other is known as differential wicking and fabrics that achieve differential wicking by the use of layers of different fiber diameters are generally known as denier gradient fabrics.
U.S. Patent Application 2002/0064639 describes several multi-layered fabrics comprising cellulosic fibers designed to reduce wet cling. One particular type of fabric that is the focus of the U.S. application comprises wicking windows that extend from the inner surface of the fabric to the outer surface of the fabric for transferring liquid from the inner surface to the outer surface. The fabric is made by applying a hydrophobic agent in a discontinuous manner to the inner surface to form regions of low surface energy and thereby leaving untreated regions of relatively high surface energy that form wicking windows. In reality, control of the coating process described in the U.S. application is extremely difficult as during application the hydrophobic agent will tend to follow the same path into the fabric as sweat would normally use, blocking off much of the wicking capability. During wear, once the fabric is saturated, the wicking windows will also be wet so the fabric is unlikely to feel dry against the skin. As the sweat is distributed homogeneously throughout all parts of the fabric not affected by the hydrophobic treatment, fabrics of this type cannot be considered to be true differential wicking structures.

SUMMARY OF THE INVENTION

The present invention is based on the realization that improved wicking of liquid from an inner face to an outer face of a fabric can be achieved by a fabric structure where the inner face of the fabric has a substantially uniform hydrophobicity and where the inner face is formed by hydrophobic yarn that is assembled in a manner that allows the liquid to penetrate the inner face and make contact with hydrophilic yarn that forms at least part of the outer face of the fabric. When liquid penetrates the inner face and makes contact with the hydrophilic yarn, the liquid can be drawn through the inner face to the outer face of the fabric.
According to the present invention there is provided a fabric including:
a) an inner face that is formed entirely from one or more than one hydrophobic yarn that has been treated to render it hydrophobic and said yarn or yarns are assembled over the inner face so that the inner face has a hydrophobicity that is substantially the same over the inner face; and
b) an outer face that in comparison to the inner face is hydrophilic and is formed at least in part by one or more than one hydrophilic yarn,
wherein the hydrophobic yarn or yarns are assembled so that liquid can penetrate the inner face and make contact with the hydrophilic yarn or yarns that form at least part of the outer face of the fabric and that, in turn, can draw liquid to the outer face of the fabric.
It is preferred that the hydrophobic yarn or yarns be assembled so that some sections of hydrophobic yarn in the inner face are separated by spaces through which the liquid can penetrate.
Throughout this specification the terms “spaces or spacings” between the hydrophobic yarns refers to the distance between the outer surfaces of the yarns.
The hydrophilic and hydrophobic yarns may include, but are not restricted to, any one or a blend of the following types of fibers: a) man-made or synthetic fibers including polyester, polyamide, polyurethane, polypropylene, polyacrylonitrile, polyvinylchloride and regenerated cellulose; and b) natural fibers including proteinaceous fibers such as wool and hair and cellulosic fibers such as cotton.
In the situation where man-made fibers or filaments are included in the hydrophobic yarn that forms the inner face of the fabric, it is preferred that the man-made yarn be treated with a hydrophobic agent.
If required, synthetic fibers may also be treated with a hydrophilic agent when incorporated in one of the hydrophilic yarns.
However, non-cellulosic man-made fibers lack the well recognized moisture buffering capacity of cotton and other cellulosic fibers. This has led us to conclude that an optimal fabric will preferably be one that is made of cotton fibers and modified cotton fibers that possesses some of the liquid wicking properties of some technical synthetic fabrics.
The following phrase, or variations thereof that describe the fabric as having “a hydrophobicity that is substantially the same over the inner face” is used throughout the specification. When the fabric is worn directly against the skin the phrase is intended to refer to the situation whereby all points of contact between the inner face of the fabric and skin are with said hydrophobic yarns that form the inner face of the fabric. The phrase embraces variations in hydrophobicity that may, for example, arise due to operational characteristics and limitations of the methods and processes used to create the hydrophobic properties of the yarns forming the inner face of the fabric. It is possible that a hydrophobic agent may be applied to yarns forming the inner face of the fabric using any of the following known techniques: padding, foam application, lick rollers, dip-hydro, spraying, printing or doctor blade. It is also possible that the yarns may be treated when assembled as a fully formed fabric or as individual yarns prior to being assembled into a fabric.
An example of a technique for creating a fabric having an inner face formed from hydrophobic yarns and having substantially the same hydrophobicity over the inner face is to laminate two separate fabric layers, one being a hydrophobic layer and another being a hydrophilic layer that have been separately manufactured and treated prior to being laminated together to form a complete fabric having an inner face and an outer face. In particular the fabric layer intended to form the inner face of the laminated fabric assembly can be treated as a fully formed fabric with a hydrophobic agent before lamination using any one or more of the known processes and techniques described above. The treated fabric layer may then be laminated with the other fabric layer that has not been treated with a hydrophobic agent using suitable adhesion techniques.
However, the preferred technique is for the pre-treated hydrophobic yarns to be woven or knitted together with one or more than one hydrophilic yarn.
It is preferred that the hydrophobic yarns be pre-treated with a hydrophobic agent prior to formation of the fabric.
Although it is possible that the fibers of the hydrophobic yarns may be treated with a hydrophobic agent while in the form of loose fibers, or at any other stage prior to the formation of a yarn such as a sliver or roving, it is preferred that the fibers be pre-treated with a hydrophobic agent when in the form of a yarn.
It is preferred that the outer face of the fabric be made predominantly from hydrophilic yarns. This can be at least in part achieved by utilising the naturally hydrophilic cellulose surface of the cotton fibers and/or other types of cellulosic fibers. The fibers may need to be scoured to remove any hydrophobic contaminants such as, natural waxes in the case of cotton. In other words, the yarns forming the outer layer are preferably not pre-treated with the hydrophobic agent that is used to treat the yarns forming the inner layer.
Throughout this specification the term “predominantly” is used to describe on a proportional basis the quantity of a particular feature. For example, in the situation where the outer face of the fabric is described as being made predominantly from hydrophilic yarn, the outer face includes at least 50 percent hydrophilic yarns on a weight basis.
It is more preferred that the outer face of the fabric be formed from 80 percent hydrophilic yarn.
It is even more preferred that the outer face of the fabric be formed from 100 percent hydrophilic yarn.
It is preferred that the hydrophobic yarns be pre-treated using an exhaust process.
Although it has been stated above that the yarns may include man-made fibers including synthetic fibers and natural fibers such as wool, it is preferred that the fibers include cotton fibers and/or other types of cellulosic fibers.
It is even more preferred that the yarns contain at least 50 percent cotton and/or other types of cellulosic fibers. Cellulosic fibers other than naturally occurring cotton fibers, include, but are by no means limited to: mercerised cotton, jute, hemp, flax, ramie, linen or regenerated cellulosic fibers such as viscose, rayon and lyocell.
It is more preferred that the yarns contain at least 80 percent cotton and/or other types of cellulosic fibers.
It is even more preferred that the yarns be made entirely of cotton and/or other types of cellulosic fibers. Simialarly, the fabric when fully formed may also be made entirely of cotton and/or other types of cellulosic fibers.
One of the advantages provided by the fabric of the present invention when made entirely of cotton and/or other cellulosic fibers is that the fabric is not at risk of melting and burning skin, that is a characteristic of many commercially available fabrics that utilize fiber denier gradients or differences in fiber surface energy between layers to create differential wicking. Differential wicking through the use of denier gradients is generally achieved with fabric structures made from thermoplastic synthetic fibers. Other fabric structures that use combinations of layers of synthetic and natural fibers to achieve differential wicking generally have the synthetic layer on the inner face of the fabric that contacts the skin.
The danger with thermoplastic synthetic fibers against skin is that the fibers can absorb enough energy to melt during exposure to intense heat sources such as a fire during an emergency situation. The resulting molten synthetic material can then adhere to skin and when it re-solidifies, the latent heat of fusion released can cause severe burns. In light of the natural resistance of cotton and other cellulosic fibers to melting, in the situation where the fabric of the present invention is formed from yarns that are entirely made of cotton and/or other types of cellulosic fibers, the fabric is well suited to clothing emergency service personnel and military personnel as well as others.
It is preferred that the pre-treated hydrophobic yarns and hydrophilic yarns be intermeshed within the fabric so as to bring the hydrophilic yarn close to but not into the inner face of the fabric.
It is preferred that the ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 95:5 to 10:90 respectively.
It is even more preferred that the ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 60:40 to 80:20 respectively.
An advantage of managing the ratio of the hydrophobic to hydrophilic yarns is that the wicking behaviour and liquid storage capacity of the fabric can be optimized.
It is preferred that the hydrophobic yarn or yarns are assembled over the inner face of the fabric so as to form loops or floats on the inner face and thereby form said sections of hydrophobic yarn separated by spaces. In this instance, the loops or floats provide structures between which liquid can penetrate to pass through the hydrophobic inner face of the fabric.
Depending on the particular application of the fabric, for example, when the fabric is being worn directly against the skin of the person, sweat excreted by a person wearing the fabric may be subject to pressure by virtue of the fabric bearing against the skin of the person and by the flexing of the fabric as the person moves. Pressure on sweat droplets of this nature may also force or assist the liquid to penetrate between the hydrophobic yarn formations on the inner face. In the situation where the fabric is worn as a second or third layer of clothing, the fabric is unlikely to have direct contact against the skin of the person. However, the same principles can still apply and liquid contacting the inner face of the fabric will be subject to pressure at least when the fabric is flexed and changes shape during movement.
Once the liquid has made contact with a hydrophilic yarn, we have realized that the liquid may be completely wicked from the inner face of the fabric to the outer face without continuous external pressures and forces that may have assisted in the liquid penetrating between the hydrophobic yarns to initiate wicking. In other words, once wicking has commenced it can continue until all of the liquid in contact with the inner face is transferred to the outer face or the capacity of the hydrophilic yarns to store liquid is exhausted.
It is preferred that the spacing of the sections of hydrophobic yarn on the inner face of the fabric range from 0.01 to 25 mm in the wale or warp direction and range from 0.01 to 25 mm in the course or weft direction. The term “spacing” refers to the distance between the outer surface of the yarns rather than the centre-to-centre distance.
It is even more preferred that the spacing of the sections of hydrophobic yarn on the inner face of the fabric is between 0.1 and 2.5 mm in the wale or warp direction and between 0.1 and 2.5 mm in the course or weft direction.
In the situation when the fabric is worn directly against the skin all points of contact between the inner face of the fabric and skin are with the hydrophobic yarns that form the inner face of the fabric. In other words, when a person wears the fabric, it is preferred that the hydrophobic yarns contact the skin of the person without hydrophilic yarns directly contacting the skin of the person. An advantage provided by this preferred aspect of the invention is that although the fabric itself may contain a large amount of liquid, the greater part of this liquid is redistributed to the outer face, so that a person wearing the fabric will not feel the fabric wet as only relatively dry hydrophobic yarns are in contact with the person's skin. This advantage may also be expressed in terms of the re-drying time of the fabric, that is, the time for a fabric in contact with skin to dry or at least feel drier than other commercially available wicking fabrics.
The hydrophobic and hydrophilic yarns are preferably intermeshed in a manner whereby the hydrophilic yarns from part of a core or central region of the fabric and the outer face of the fabric. The hydrophilic yarn does not appear in the inside face of the fabric but is located below the surface at points where liquid penetrating the hydrophobic face can make contact with it.
It is preferred that the hydrophilic yarn be located at a distance ranging from 0.01 to 2.0 mm from an outer plane of the inner face of the fabric.
It is even more preferred that the hydrophilic yarn be located at a distance ranging from 0.1 to 1.0 mm from an outer plane of the inner face of the fabric.
Examples of knitted fabric structures that may be employed in forming the fabric include both all-needle and half-gauge double knits, single jersey plated structures, and collapsed rib structures involving elastomeric yarns. Examples of woven fabric structures that may be employed in forming the fabric include twills, sateens, satins and double cloths.
It is preferred that the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.1 to 1.
It is even more preferred that the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.9 to 1.
It is also preferred that the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 250.
It is even more preferred that the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 5.
The Hohenstein Institute standard tests referred to in the preceding paragraphs are described in more detail on pages 31 and 32 under the heading

DETAILED DESCRIPTION

According to the present invention there is also provided a fabric including:
a) an inner face that is formed entirely from one or more than one hydrophobic yarn and said yarns are assembled over the inner face so that the inner face has a hydrophobicity that is substantially the same over the inner surface and is suitable for making the inside of a garment, wherein said yarns include cotton and/or other types of cellulosic fibers and have been pre-treated with a hydrophobic agent prior to formation of the fabric, and
b) an outer face that in comparison to the inner face is relatively hydrophilic such that liquid can be wicked through the inner face to the outer face, and wherein the outer face is made of yarns that include cotton and/or other types of cellulosic fibers.
According to the present invention there is provided a fabric including:
a) an inner face that is hydrophobic and has a hydrophobicity that is substantially the same over the inner face, and is suitable for making the inside of a garment; and
b) an outer face that in comparison to the inner face is hydrophilic whereby liquid contacting the inner face can be wicked through the fabric to the outer face without being retained by the inner face, and wherein the inner and outer faces of the fabric are made of yarns that include cotton fibers and/or other types of cellulosic fibers.
According to the present invention there is provided a fabric including:
a) an inner face that is formed entirely from one or more than one hydrophobic yarn and said yarn or yarns are assembled over the inner face so that the inner face has a hydrophobicity that is substantially the same over the inner face, and wherein said yarns include cotton fibers and/or other types of cellulosic fibers; and
b) an outer face that in comparison to the inner face is hydrophilic whereby liquid contacting the inner face can be wicked through the fabric to the outer face and wherein the outer face is made of yarns that include cotton fibers and/or other types of cellulosic fibers.
It is preferred that the hydrophobic yarns that are assembled over the inner face of the fabric be intermeshed with the hydrophilic yarns that form at least part of the outer face of the fabric and the hydrophobic yarns are arranged so that liquid is able to be drawn through the hydrophobic face by the hydrophilic yarns.
According to the present invention there is also provided a method of making a fabric that is capable of wicking liquid through an inner face to an outer face of the fabric. The method includes the steps of:
a) providing a hydrophilic yarn;
b) providing a hydrophobic yarn that has been treated to render it hydrophobic; and
c) forming a fabric using said hydrophilic and hydrophobic yarns, wherein the yarns are assembled relative to each other such that the inner face of the fabric is made entirely from the hydrophobic yarn and the hydrophobic yarns are arranged in the inner face so that liquid can penetrate and make contact with hydrophilic yarn that forms at least part of the outer face of the fabric.
It is preferred that step b) include pre-treating fibers of the hydrophobic yarn with a hydrophobic agent which results in the hydrophobic agent being fixed to the fibers.
Preferably, the hydrophilic yarn does not appear in the inner face of the fabric but is located below the surface and can draw liquid through the inner face to the outer face of the fabric.
It is preferred that the hydrophobic yarns are arranged so that some sections of the hydrophobic yarn are separated by spaces that liquid can penetrate.
It is preferred that the hydrophilic and hydrophobic yarns include but are not limited to any one or a blend of the following types of fibers:
a) man-made or synthetic fibers including polyester, polyamide, polyurethane, polypropylene, polyacrylonitrile, polyvinylchloride and regenerated cellulose; and
b) natural fibers including proteinaceous fibers such as wool and hair and cellulosic fibers such as cotton.
According to the present invention there is provided a method of making a fabric including one or more than one hydrophobic yarn and one or more than one hydrophilic yarn that includes cotton and/or other types of cellulosic fibers, the yarns being woven or knitted together such that an inner face of the fabric is formed entirely from the hydrophobic yarns so that the hydrophobicity of the inner face is substantially the same over the inner face and an outer face of the fabric that is, by comparison, hydrophilic such that liquid can be wicked through the fabric from the inner face to the outer face. The method includes the step of pre-treating the cotton and/or other types of cellulosic fibers of the hydrophobic yarn that forms the inner face of the fabric with a liquor containing a hydrophobic agent prior to the yarn being used to make the fabric.
Although it has been stated above that the yarns may include man-made fibers including synthetic fibers and natural fibers such as wool, it is preferred that the fibers include cotton fibers and/or other types of cellulosic fibers.
It is even more preferred that at least one of the yarns contain at least 50 percent cotton and/or other types of cellulosic fibers.
Cellulosic fibers other than naturally occurring cotton fibers include, but are by no means limited to: mercerised cotton, jute, hemp, flax, ramie, linen or regenerated cellulosic fibers such as viscose, rayon and lyocell.
It is more preferred that at least one of the yarns contain at least 80 percent cotton and/or other types of cellulosic fibers.
It is even more preferred that said yarns be made entirely of cotton and/or other types of cellulosic fibers.
It is preferred that the step b) include pre-treating the fibers with a liquor containing a hydrophobic agent and results in the hydrophobic agent being fixed to the fibers.
According to the present invention there is also provided a method of making a fabric that is capable of wicking liquid through an inner face to an outer face of the fabric and the fabric includes two or more than two yarns that include cotton fibers and/or other types of cellulosic fibers. The method includes the steps of:
a) pre-treating the scoured cotton fibers and/or other types of cellulosic fibers of at least one of the yarns with a liquor containing a hydrophobic agent so as to impart hydrophobic properties to the fibers; and
b) forming a fabric from two or more yarns of which at least one yarn includes the cotton fibers and/or other types of cellulosic fibers pre-treated according to step a) and, wherein the yarns are assembled relative to each other such that the inner face of the fabric is made entirely from said yarn containing fibers pre-treated according to step a) and that the inner face of the fabric is hydrophobic compared to the outer face and has a hydrophobicity that is substantially the same over the inner face.
It is preferred that the step of pre-treating the cotton fibers and/or other cellulosic fibers with the liquor containing a hydrophobic agent results in the hydrophobic agent being fixed to the fibers.
Throughout this specification the phrase “the hydrophobic agent being fixed onto the fibers” embraces any physical adsorption or chemical reaction whereby the hydrophobic agent becomes fixed to the cotton fiber. Examples of adsorption and reactions that may cause the hydrophobic agent to become fixed to the cellulosic fibers include, but are not limited to, ionic bonding and exchange, covalent bonding and exchange, van der Waals (non-dispersive) bonding and exchange or so called dipole-dipole bonding and exchange and variations thereof.
It will be appreciated that step a) may be carried out either before, during or after the cotton fibers and/or other types of cellulosic fibers are spun into a yarn.
It is also possible that the cotton fibers and/or other types of cellulosic fibers pre-treated according to step a) may be provided in any form including loose fibers, sliver, rovings, spun yarns, hanks, and even woven, knitted or non-woven fabric. However, it is preferred that the fibers pre-treated according to step a) be in the form of a spun yarn.
It is preferred that the yarns including cotton fibers and/or other types of cellulosic fibers consist entirely of cotton fibers. However, it is also possible that the yarns may include blends of cotton fibers with other cellulosic fibers and non-cellulosic fibers such as polyester. It is to be understood that cellulosic fibers other than naturally occurring cotton fibers include but are not limited to the following types of fibers: mercerised cotton, jute, hemp, flax, ramie, linen or regenerated cellulosic fibers such as viscose, rayon and lyocell.
In the situation in which the cotton fibers and/or other types of cellulosic fibers pre-treated by step a) are in the form of fabric, the fabric can be unravelled to form a continuous yarn or thread that can be further processed with another yarn in accordance with step b) of the method of the present invention. The method whereby a knitted fabric is pre-treated then unravelled into yarn and re-formed into fabric is known as the knit-de-knit process.
It will also be appreciated that steps a) and b) may be carried out consecutively or disjunctively.
It is possible that step a) may be carried out using various techniques that allow the liquor to contact the cotton fibers and/or other types of cellulosic fibers. For example, depending on the form in which the fibers are provided, the liquor containing the hydrophobic agent may contact the fibers by padding, rolling or spraying the liquor onto the fibers. However, it is preferred that step a)involves submerging the cotton fibers in the liquor so that the hydrophobic agent is preferentially adsorbed onto the cotton fibers from the liquor.
In the situation in which the fibers pre-treated by step a) are in the form of a spun yarn wound onto a tube to form a yarn package, it is preferred that step a) involves contacting the fibers with the liquor using an exhaust process.
Exhaust processes are known at present as suitable for applying dyestuffs to yarns and involve placing one or more than one yarn package into an enclosed vessel that may be pressurized and pumping the dyestuff through the yarns. It has been found that a hydrophobic agent can be fixed to the fibers satisfactorily using an exhaust process.
It is our understanding that exhaust processes provide a more durable application of the hydrophobic agent compared to other possible techniques such as padding, foam application, lick rollers, dip-hydro, spraying, printing or doctor blade. As a result, the wicking behaviour of the fabric manufactured from fibers that have been subjected to exhaust treatment according to this preferred embodiment can demonstrate a greater retention of the wicking properties after numerous wash and wear cycles.
Although step a) may be carried out at any suitable temperature, it is preferred that step a) be carried out at a temperature ranging from 10 to 110° C.
It is even more preferred that step a) be carried out at a temperature ranging from 20 to 70° C.
It is preferred that step a) be carried out at a starting temperature of 10° C. increasing at a rate ranging from 0.1 to 5.0 degrees per minute to a maximum of 110° C.
It is even more preferred that step a) be carried out at a starting temperature of 20° C. increasing at a rate ranging from 0.5 to 1.5 degrees per minute to a maximum of 70° C.
Examples of hydrophobic agents that may be used in step a) of the present invention include but are not limited to any one or a combination of silicones, fluorochemicals, oils, latexes and hydrocarbons. It is preferred that the hydrophobic agent included in the liquor be a fluoroacrylate polymer.
An advantage provided by the preferred hydrophobic agent is that the fabric can be piece dyed using conventional dyestuffs such as reactive dyes without shade differences between treated and untreated yarns in the same fabric. In addition, the dyeing treatment does not change the wicking mechanism of the fabric.
The useable life of the new fabric made by the method of the present invention is determined by the number of wash and wear cycles that can be endured before wicking of liquid no longer preferentially occurs from the inner face to the outer face. This in turn is a function of the resistance of the hydrophobic agent to physical damage and/or leaching during the washing process.
In order to prolong the wicking characteristics of the fabric, it is preferred the hydrophobic agent be capable of forming covalent bonds to the surface of cotton and/or other types of cellulosic fibers treated according to step a).
The rate of uptake of the hydrophobic agent from the liquor and the uniformity of the deposition of the hydrophobic agent throughout the yarn packages may be dependent on the availability of an electrolyte. Similarly, depending on the nature of the hydrophobic agent used, the ability to completely exhaust the hydrophobic agent from the liquor and to avoid undesired deposition of polymer onto the treatment vessel or flocculation of hydrophobic agent, the liquor may need to contain an electrolyte.
It is preferred that the treatment liquor also includes an electrolyte. The electrolyte may be any suitable electrolyte such as sodium sulphate or magnesium chloride.
In the situation where the liquor includes an electrolyte it is preferred that step a) involve controlling the concentration of electrolyte in the solution. Controlling the concentration may be required to achieve both uniform application of the hydrophobic agent and complete exhaustion of the hydrophobic agent from the liquor.
It is preferred that the electrolyte concentration range from 0 to 20 g/l.
It is even more preferred that the electrolyte concentration range from 5 to 10 g/l.
Irrespective of whether the hydrophobic agent may or may not be able to form covalent bonds with cotton or other types of cellulosic fibers, in order to further increase the stability and therefore the duration over which the hydrophobic agent is effective, it is preferred that the treatment liquor include a cross-linking agent for forming bonds between the hydrophobic agent and the cotton or other cellulosic fibers. Hydrophobic agents that contain isocyanate cross-linkers that bond the fiber and/or to the substratate may be beneficial to this treatment.
In addition, it is possible the cross-linking agent may also become fixed to the cellulosic fiber itself. For example, a cross-linking agent may react with the hydroxyl groups present on the surface of the cotton fibers and/or other types of cellulosic fibers.
The principal advantage in using a cross-linking agent is to increase the durability of the hydrophobic agent to laundering.
It is even further preferred that the cross-linking agent be heat activated.
In order to activate the cross-linking agent, it is preferred that the method also include a heat curing step in which the pre-treated yarn is heated to a temperature ranging from 50 to 230° C.
It is even more preferred that the curing step involve heating the pre-treated yarn to a temperature ranging from 110 to 190° C.
The heat curing step may be carried out for any suitable period; however, periods ranging from 1 second to 40 minutes are preferred. It is more preferred that the heat curing step is carried out for a time period ranging 30 seconds to 20 minutes or any period within that range.
The heat curing step may be carried out at a variety of different stages of the method of the present invention, such as either before or after step b). In the instance in which the fabric is knitted, it has been found that a knitting lubricant can be applied to a yarn pre-treated according to step a) to facilitate knitting and the knitting lubricant can subsequently be removed using conventional scouring techniques before or after curing without adversely effecting the hydrophobic pre-treatment. In this situation, the curing step is carried out after step b).
Similarly, it is also possible for the heat curing step to be carried out before the yarn is knitted or woven with another yarn.
According to the present invention there is also provided a garment including the fabric as described above. The fabric from which the garment is made may also include any one or a combination of the preferred or optional features described above. Although the garment may be any outer garment such as a pair trousers, a shirt or a jacket, it is preferred that the garment be a base layer garment worn against the skin. Fabrics as described herein may also be used as a component of an item of clothing or clothing system. For example, these fabrics can be laminated to one face of a functional film together with a second fabric on the other face using well know lamination technology such as adhesive printing or coating. They can also be used as both faces of such a construction to produce a reversible fabric. The functional film can be a waterproof and/or windproof breathable membrane. Liquid sweat picked up is transported to the hydrophilic layer next to the adjoining functional film and can influence the breathability of the film in a positive way. Laminated fabrics of this type are well suited for industrial and outdoor sports applications.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying diagrams, of which:
FIG. 1 is a structural profile of a section of fabric in accordance with an embodiment of the invention;
FIGS. 2 and 3 are flow diagrams illustrating the method steps for making a fabric according to alternative embodiments of the invention; and
FIGS. 4 and 5 show a structural profile of a section of fabric in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention will now be described with reference to the fabric structure shown in FIG. 1. The fabric is preferably made from two or more yarns consisting entirely of cotton yarns. However, it will be appreciated that it is within the scope of the present invention that the cotton yarns may be partially or completely substituted with other types of cellulosic fibers or even synthetic fibers. In other words, other embodiments of the present invention may have yarns that are made entirely of man-made fibers or blends of the synthetic and cellulosic fibers.
The fabric shown in FIG. 1 includes an inner face generally identified by reference numeral 10 that is made entirely from yarns containing cotton fibers that prior to fabric formation have been pre-treated in the form of a yarn with a hydrophobic agent in accordance with the method described herein. The pre-treated yarn exhibits a substantially permanent hydrophobic property and is arranged such that the inner face 10 of the fabric has a substantially uniform hydrophobic surface. In contrast, an outer face of the fabric identified by reference numeral 20 is made from yarns containing cotton fibers that are not pre-treated with a hydrophobic agent and have been scoured so that they exhibit the natural hydrophilic properties of the cellulosic surface. The difference in hydrophilicity or surface energy between the inner face 10 and outer face 20 of the fabric enables liquid to be wicked through the fabric from inside to outside in the direction of the arrows 30 shown in FIG. 1.
The fabric preferably has a layered structure in which the hydrophobic and hydrophilic cotton yarns 11 and 12 respectively are intermeshed within the fabric so as to bring the hydrophilic yarn 12 toward the inner face 10 of the fabric but not actually form part of that face 10. More particularly, as shown in FIG. 1, it is preferred that the hydrophobic yarn 11 be assembled so as form loops or floats 13 that form the inner face 10 of the fabric. The loops and floats 13 are spaced sufficiently apart to allow liquid such as sweat drops to penetrate between the loops and floats 13 and when located between the loops 13 the liquid is able to make contact with the hydrophilic yarn 12 that forms part of the outer face of the fabric. Once the liquid has made contact with the hydrophilic yarn 12, the hydrophilic yarn 12 draws liquid through the inner face 10 to the outer face 20 of the fabric. External pressure applied to the liquid such as pressure on the liquid caused by movement between the fabric and skin of a person wearing the fabric. In any event once the wicking path is created, wicking can continue until all the liquid is removed from the inner face 10 of the fabric or until the capacity of the hydrophilic yarn 12 to store liquid is exhausted.
Although the structural profile shown in FIG. 1 illustrates the loops or floats 13 separated over by relatively consistent spaces, it will be appreciated that the spacing between the hydrophobic yarn of a fabric is likely to vary at least to some extent in view of current manufacturing variables including yarn tension and diameter. In addition, depending on the particular fabric structure chosen it is possible for the fabric pattern to having two or more than two loops 13 immediately adjacent to one another at regular intervals, yet be spatially separated from neighbouring loops. In any event, the nett result is that the inner face 10 of the fabric has a hydrophobicity that is substantially the same over the inner face 10 and the loops 13 are assembled so that sections of the hydrophobic yarn 11, typically the loops 13, are separated so as to form spacing or voids without hydrophobic yarns in the inner face 10 into which liquid can penetrate and make contact with the hydrophilic yarn 12. The liquid can then be wicked to the outer face of the fabric as described above.
FIG. 2 is a flow diagram according to an embodiment of the present invention in which cotton fibers spun into yarns are wound onto one or more tubes to form yarn packages at a first stage. The yarn packages are initially scoured then treated with liquor containing a hydrophobic agent, so that the agent is adsorbed directly onto the cotton fibers. The hydrophobic agent is preferably a fluoroacrylate polymer. In addition, the liquor may include a heat-activated cross-linking agent that is applied to the cotton yarn during the hydrophobic pre-treatment stage.
The liquor preferably includes the hydrophobic agent as an emulsion. The rate at which the hydrophobic agent is deposited onto the cotton fibers and the uniformity of the deposition of the hydrophobic agent throughout the yarn packages will depend on a number of operational parameters including the size and concentration of the particles in the emulsion, the residence time or period over which the yarns are treated, the temperature of the liquor and the rate at which the temperature is raised between a start temperature and a finish temperature. The rate of uptake of the particles from the emulsion is also a function of the concentration of electrolyte, such as sodium sulphate, contained by the liquor. Indeed, in order to achieve complete exhaustion of the particles from the liquor, an optimal concentration of electrolyte may be required to avoid flocculation of hydrophobic agent or deposition of the hydrophobic agent on equipment items.
It is preferred that the particle size of this emulsion at room temperature is less than 500 nm. It is even more preferred that the particle size of the emulsion at room temperature is less than 240 nm and most preferred if the size is less than 120 nm.
Following the hydrophobic agent pre-treatment stage the cotton yarns are processed in a heat curing oven to activate the cross-linking agent. When activated the cross-linking agent can form bonds between the hydrophobic agent adsorbed onto the cotton fibers and depending on the type of the cross-linking agent, it may itself also bond with the cotton fiber. In any event, the purpose of the cross-linking agent is to further increase the resistance of the hydrophobic treatment to laundering. Preferably, the heat curing stage heats the cotton fibers to a substantially uniform temperature of approximately 150° C. In order to achieve a substantially uniform temperature in the least amount of time the yarn may be unwound from each yarn package.
A friction-reducing knitting lubricant is then applied to the pre-treated yarn and the yarn knitted with a second, hydrophilic cotton yarn to form a fabric into a differential wicking structure. The fabric is then scoured to remove the knitting lubricant prior to the fabric being converted into a garment. We have found that with some hydrophobic agents the knitting lubricant can be removed by scouring without adversely affecting the performance of the hydrophobic agent.
The hydrophobic treatment stage may be carried out using any suitable technique that allows the hydrophobic agent to contact and become fixed to the cotton fibers. Examples of possible types of techniques that may be employed for contacting the fibers with the liquor include padding, foam application, lick rollers, dip-hydro, spraying, printing and doctor blade. However, it is preferred that the liquor contacts the cotton fibers by submerging the cotton fibers in the liquor. An example of a process in which fibers are submerged in a liquid is an exhaust process. Conventionally, exhaust processes have been used for dyeing fibers with colour dyestuffs.
FIG. 3 is a flow diagram of an alternative embodiment that is the same as the embodiment shown in FIG. 2, save for the heat curing step being carried out on the cotton yarn after the hydrophobic yarn has been formed into a fabric. Specifically, FIG. 3 illustrates a method including the stages of: i) spinning and winding a cotton yarn onto a tube; ii) scouring the yarn to remove surface contaminants; iii) adsorbing a hydrophobic agent onto the cotton yarn in a pre-treatment stage; iv) knitting or weaving the pre-treated yarn with at least one other yarn so as to make a fabric; v) removing lubricants and other processing aids from the fabric using conventional scouring techniques; vi) heat curing the hydrophobic agent and cross-linking agent if present; and finally converting the fabric into a garment.
Although not shown in either FIG. 2 or 3, it is also possible that the heat curing stage may be carried out before the scouring. In addition, it is also possible that the liquor containing the hydrophobic and cross-linking agents may also include a knitting lubricant that is applied to the cotton yarns during the hydrophobic pre-treatment stage.
The superior wicking performance of a fabric manufactured according the embodiment of the present invention described above can be demonstrated by a test that assesses the relative amounts of water in the inner and outer faces of the fabric after contact with water. The test method may be summarised as follows. Initially test specimens of fabric (measuring 100 mm×100 mm) are selected and stored at relative humidity of 65% at 20° C. for a period of 4 hours prior to testing to ensure homogeneous moisture content in the fabric. A fixed volume of water is then placed near the centre of the inside face of each specimen using a pipette. After the water has been totally absorbed, the fabric is sandwiched between two pieces of absorbent paper and laid flat for a short time with pressure applied uniformly over the surface. The weight of water absorbed by each piece of paper is measured and recorded. The ratio of these two weights is quoted as the mass wicking ratio. The test is repeated with the opposite face upward and the results averaged to eliminate gravitational effects.
An alternative means of assessing the effect of differential wicking is to measure the area of spread of the water on each face of test specimens prepared as described in the preceding test immediately after a fixed volume of water has been fully absorbed. The ratio of these two areas is quoted as the area wicking ratio.
The table set out below provides the results of the wicking performance of 5 different types of fabrics. Fabric type 1 is a conventional 100% cotton fabric. Fabric type 2 is a prior art cotton fabric that has a hydrophobic layer printed on the inner face of the fabric in accordance with other commercially available fabrics. Fabric type 3 is a cotton fabric comprising a hydrophobic inner face made from a hydrophobic yarn in accordance with an embodiment of the present invention. Fabric type 4 is a prior art fabric comprising an inner face made with a polypropylene yarn and an outer face made with a cotton yarn. Fabric type 5 is a prior art fabric in the form of a polyester double-knit.

Mass wicking ratio

Fabric type outer:inner

1 1.0

2 5.0

3 33

4 7.9

5 1.0
The invention will now be further described with reference to the following non-limiting examples, which are provided for illustration purposes only and are not to be interpreted as defining the scope of the invention.

EXAMPLE 1

This example demonstrates fabrication of a double knit fabric manufactured from hydrophilic cotton yarn for the outer face and hydrophobic cotton yarn for the inner face. Both yarns are first scoured and bleached using a conventional cotton procedure. This renders the surface of the cotton hydrophilic. The yarn to be used for the inner face of the fabric is then treated with Nuva TTC (Clariant) by an exhaust process using the apparatus and method described above to render it hydrophobic. The yarn package size used is 900 g wound to a density of 0.3 g/cc and the yarn is treated under the follows conditions:



	Liquor ratio	12:1

Nuva TTC	5%	on mass of yarn
Sodium Sulphate	8	g/l
Start temperature
20°	C.
Finish temperature	70°	C.
Temperature increase	0.5°	C./min
Hold time at 70° C.	15	min
Liquor flow cycle	4	minutes out-to-in,
	3	minutes in-to-out

The liquor clears progressively during the treatment cycle and at the end of the treatment time, the liquor is completely clear, indicating that exhaustion onto the yarn is complete.
The liquor is drained from the apparatus without rinsing and the yarn packages hydro-extracted and dried at 80° C. The yarn is then rewound and waxed with a paraffin lubricant prior to knitting.
Fabric manufacture is carried out on a double-jersey knitting machine. After knitting, the fabric is scoured to remove the knitting wax for 30 minutes at 65° C. in the presence of 1 g/L Hostapal FA-Z (Clariant) and 1 g/L sodium carbonate. The liquor is drained at a temperature of 65° C. to prevent re-deposition of the emulsified wax. The fabric is rinsed twice for 10 minutes at 40° C., hydro-extracted and dried on a stenter. During the drying process the fabric is subjected to a temperature of 145° C. for 5 minutes to cure the hydrophobic agent.
The fabric exhibits differential wicking behaviour that is retained for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 2

This example is the same as Example 1, save for the step of curing the fabric being carried out after knitting and before the final scour to remove lubricant.
The fabric exhibits differential wicking behaviour that is retained for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 3

This example is the same as Example 1, except for the softener/lubricant Sandolube SVN being co-applied with the hydrophobic agent atthe rate of 1% on mass of fiber during the yarn treatment step. The Sandolube replaces the paraffin knitting lubricant added during re-winding in Example 1.
The fabric exhibits differential wicking behaviour that is retained for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 4

In this example, finished fabric prepared using the procedure described in Example 1 is piece dyed using a conventional reactive dyeing procedure applicable to cotton goods.
The fabric exhibits differential wicking behaviour that is retained for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 5

This example is the same as Example 1, save for both yarns being dyed prior to treatment and knitting into fabric using conventional cotton colouration technology. In this instance, the preparatory scouring and bleaching step are not required. The yarn to be used for the hydrophobic face is given a mild scour with sodium carbonate to remove any residual contaminants and loose dyestuff prior to treatment with the hydrophobic agent. The fabric exhibits the required differential wicking behaviour for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 6

This example is the same as Example 1, save for the hydrophobic yarn being prepared by a knit-de-knit process with the hydrophobic agent applied to the fabric by a conventional pad/dry/cure process. The cotton yarn used for the hydrophobic face is first scoured and bleached then knitted into a single jersey tube on a single-feed FAK laboratory machine. Nuva TTC is padded onto the tubular fabric piece at 5% on mass of fabric by means of a small mangle. The fabric is subsequently dried and the polymer heat cured. The yarn is unravelled from the piece (de-knitted), re-wound and waxed in preparation for knitting.
The fabric exhibits differential wicking behaviour that is retained for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 7

In this example the yarn to be used for the inner face of the fabric is treated with Ruco-Dry DFE (Rudolf Chemie) as a hydrophobic agent. The method and apparatus for carrying out the manufacture and all operating conditions of the treatment process are the same as described in Example 1, save for the following treatment conditions:

Liquor ratio 10:1

Ruco-Dry DFE 5% on mass of yarn

Start temperature 25° C.

Finish temperature 40° C.

Temperature increase 1.5° C./min

Hold time at 40° C. 10 min

The fabric exhibits the required differential wicking behaviour for a minimum of 30 home laundry wash and tumble dry cycles. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 8

This example demonstrates fabrication of a double knit fabric manufactured from 1/30s Cotton Count (20 Tex) hydrophilic cotton yarn for the outer face and 1/50s Cotton Count (12 Tex) hydrophobic cotton yarn for the inner face. Both yarns are scoured and the hydrophobic yarn treated as for Example 1.
Fabric manufacture is carried out on a double-jersey knitting machine of 28 needles per inch (28 gauge). At the first knitting point or feed, the hydrophilic yarn is knitted on all needles on one needle bed only. This is repeated at the next feed. At the third feed, the hydrophobic yarn is knitted on alternate needles of the second needle bed and tucked across to alternate needles of the first bed. This sequence is repeated for the next group of three feeds on the knitting machine, except that the hydrophobic yarn is tucked to those needles omitted at the preceding hydrophobic course. The fabric has a mass ratio of hydrophilic yarn to hydrophobic yarn of 75:25.
The liquid water buffering index K_fof the fabric when measured by the procedure described on page 27 is 0.99 and its moisture sorption index i_Bis 0.7, both of which are within the range of preferred values for these properties. The mass wicking ratio determined by the test method described above is 18:1. Differential wicking behaviour is retained for in excess of 30 cycles of home laundering and tumble drying. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.

EXAMPLE 9

This example demonstrates fabrication of a double knit fabric manufactured from a hydrophilic 78 dtexpolyester (PES) filament yarn for the outer face and Ne 1/50s Cotton Count (12 Tex) hydrophobic cotton yarn for the inner face. The hydrophobic yarn is scoured and treated as in Example 1. In this example an Elasthane yarn is worked up between the outer hydrophilic face and the inner hydrophobic face.
Fabric manufacture is carried out on a double-jersey knitting machine of 28 needles per inch (28 gauge). At the first knitting point or feed, the hydrophilic yarn is knitted on all needles on one needle bed only. This is repeated at the next feed. At the third feed, the hydrophobic yarn is knitted on alternate needles of the second needle bed and tucked across to alternate needles of the first bed. This sequence is repeated for the next group of three feeds on the knitting machine, except that the hydrophobic yarn is tucked to those needles omitted at the preceding hydrophobic course. The fabric has a mass ratio of hydrophilic yarn to hydrophobic yarn and Elasthane of 45:45:10.
The liquid water buffering index K_fof the fabric when measured by the procedure described below is 0.95 and its moisture sorption index i_Bis 0.7, both of which are within the range of preferred values for these properties. The mass wicking ratio determined by the test method described above is 19:1. Differential wicking behaviour is retained for in excess of 30 cycles of home laundering and tumble drying. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.
The use of PES yarn for the outer face is advantageous because a PES yarn is known as a fast drying yarn and therefore the outer face is able to dry very fast. Furthermore the “cotton feeling” on the skin is maintained.

EXAMPLE 10

This Example demonstrates fabrication of a double knit fabric manufactured from Nm 66 wool yarn for the outer face and 1/50s Cotton Count (12 Tex) hydrophobic cotton yarn for the inner face. The hydrophobic yarn is scoured and treated as in Example 1. In this example an Elasthane yarn is worked up between the outer hydrophilic face and the inner hydrophobic face.
Fabric manufacture is carried out on a double-jersey knitting machine of 28 needles per inch (28 gauge). At the first knitting point or feed, the wool yarn is knitted on all needles on one needle bed only. This is repeated at the next feed. At the third feed, the hydrophobic yarn is knitted on alternate needles of the second needle bed and tucked across to alternate needles of the first bed. This sequence is repeated for the next group of three feeds on the knitting machine, except that the wool yarn is tucked to those needles omitted at the preceding hydrophobic course. The fabric has a mass ratio of wool yarn to hydrophobic yarn and Elasthane of 60:30:10.
The liquid water buffering index K_fof the fabric when measured by the procedure described below is 0.9 and its moisture sorption index i_Bis 4.5 both of which are within the range of preferred values for these properties. The mass wicking ratio determined by the test method described above is 12:1. Differential wicking behaviour is retained for in excess of 30 cycles of home laundering and tumble drying. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.
The use of wool yarn is advantageous because wool has very high insulation properties which are useful for specific outdoor applications, like alpin skiing, ice climbing etc. Furthermore, this combination of yarns provides the wearer with the preferred cotton feeling on the skin.

EXAMPLE 11

This Example demonstrates fabrication of a double weave structure manufactured from hydrophilic cotton yarn for the outer face and hydrophobic cotton yarn for the inner face. The hydrophilic cotton yarn is a Nm 64/2 yarn and the hydrophobic yarns are a mixture out of different yarn counts: Nm 64/2, Nm 32/2, Nm 112/2 yarn. Other embodiments may have hydrophilic yarns that are made of wool or synthetic fibers like PES.
Both yarns are scoured and the hydrophobic yarn treated as in Example 1. Fabric manufacture is carried out on a double weave machine.
A double weave fabric may be defined as a compound woven fabric where two sets of warp yarns and weft yarns allow the outer face and the inner face of the fabric to show different patterns or have different properties. One set of warp and weft yarns preferably comprises hydrophilic cotton yarns (forming the outer face) and the other set or yarns preferably comprise hydrophobic cotton yarns (forming the inner face). In a double weave fabric, the fabric has two fabric layers and some yarns from one fabric layer interlace with the other fabric layer so that the fabrics layers are held together. Preferably some yarns from the outer hydrophilic fabric layer interlace with the inner hydrophobic fabric layer in such a way that no hydrophilic yarns are present on the inner surface.
The outer face of the double weave fabric has a Twill of 2/1 and the inner face has a Twill with a rib-structure. The fabric has a mass ratio of hydrophilic yarn to hydrophobic yarn of 60:30.
The liquid water buffering index K_fof the fabric when measured by the procedure described below is 0.99 and its moisture sorption index i_Bis 0.7, both of which are within the range of preferred values for these properties. The mass wicking ratio determined by the test method described above is 18:1. Differential wicking behaviour is retained for in excess of 30 cycles of home laundering and tumble drying. Washing is carried out at 60° C. using a 2A Cotton Cycle in accordance with ISO 6330 with ECE detergent, while tumble drying is carried out cool for 60 minutes.
FIGS. 4 and 5 show one embodiment of this example of the double weave fabric.
FIG. 4 shows schematically a top view of the inner hydrophobic face of a section of the double weave woven fabric according to Example 4. The double weave fabric comprising a first hydrophobic fabric layer 105 and a second hydrophilic fabric layer (not visible in the drawing). The first hydrophobic fabric layer 105 includes an inner face 100 that is made entirely from yarns containing cotton fibres that prior to fabric formation have been pre-treated in the form of a yarn with a hydrophobic agent in accordance with the method described above. The hydrophobic warp yarns 112 and hydrophobic weft yarns 114 are woven together forming the first fabric layer 105. The second hydrophilic fabric layer (not visible) comprising hydrophilic cotton yarns and is arranged behind the first fabric layer. The hydrophilic warp yarns and hydrophilic weft yarns are woven together forming the second fabric layer. Some hydrophilic yarns 122 from the outer second fabric layer interlace with the inner hydrophobic fabric layer 105 permanent within the layered structure of the fabric so as to bring the hydrophilic yarn 122 toward the inner face 100 of the fabric but not actually form part of that face 100.
More particularly as shown in FIG. 4, the hydrophobic warp yarns 112 are spaced sufficiently apart to allow liquid such as sweat drops to penetrate between the hydrophobic warp yarns 112 and when located between the hydrophobic yarns the liquid is able to make contact with the hydrophilic yarn 122 that forms part of the outer face of the fabric. Such space has the reference number 200. Once the liquid has made contact with the hydrophilic yarn 122, the hydrophilic yarn 122 draws liquid through the inner face 100 to the outer face of the fabric. In any event once the wicking path is created, wicking can continue until all the liquid is removed from the inner face 100 of the fabric or until the capacity of the hydrophilic yarn 122 to store liquid is exhausted.
Although the structural top view shown in FIG. 4 illustrates the warp yarns 112 or weft yarns 114 separated over by relatively consistent spaces, it will be appreciated that the spacing between the hydrophobic yarn of a fabric is likely to vary at least to some extent in view of current manufacturing variables including yarn tension and diameter. In any event, the result is that the inner face 100 of the double weave fabric has a hydrophobicity that is substantially the same over the inner face 100 and the hydrophobic warp yarns 112 and weft yarns 114 are assembled so that sections of the hydrophobic yarn 112, 114 typically the warp yarns 112, are separated so as to form spacing or voids 200 into which liquid can penetrate and make contact with the hydrophilic yarn 122. The liquid can then be wicked to the outer face of the fabric as described above.
FIG. 5 is a structural profile of a section of a double weave fabric in accordance with Example 4 of the invention.
Those skilled in the art of the present invention will appreciate that many modifications may be made to the preferred embodiment without departing from the spirit and scope of the present invention.
It is preferred that fabrics manufactured in accordance with the present invention satisfy performance criteria that can be measured in accordance with standard tests of the Hohenstein Institute of Bönnigheim, Germany. The tests are designed to rate the liquid water wicking and drying behaviour of fabrics and may be summarized as follows:
1. The Buffering Capacity against Liquid Water, K_f
This test is described in Standard Test Specification BPI 1.2 ‘Testing of Textiles—Measurement of the Buffering Capacity of Textiles with the Thermoregulatory Model of Human Skin (Skin Model)’, Bekleidungsphysiologisches Institut E. V. Hohenstein, March 1994.
The determination of K_fis carried out on a guarded hot plate located within a climate-controlled cabinet. A system incorporating these two items, known widely as the Hohenstein Skin Model, has a specific configuration and a defined airflow across the hot plate. The central plate dimensions are 20 cm×20 cm and the plate is heated to a temperature of 35° C. The conditions within the cabinet are controlled at 35° C. and 30% relative humidity. An impermeable film is placed on the surface of the guarded hot plate and a thin, wicking polyester fabric is placed over the film. Test specimens measuring 21 cm×21 cm are used, pre-conditioned for 12 hours prior to the test at the same temperature and humidity as the air in the cabinet. The quantity of 15 cc of distilled water at a temperature of 35° C. is uniformly distributed over the polyester with a hypodermic syringe and the test specimen is immediately placed over it, centred on the plate.
Some of the water is absorbed or wicked up by the fabric, some evaporates either at the plate or from the fabric and some remains in the polyester. After a fixed 15-minute period, the fabric is removed and weighed. The amount of water evaporated into the cabinet G₁is determined from the mass of water removed from the air in the cabinet in order to maintain constant humidity conditions. The amount of water remaining in the fabric G₂is determined by subtracting the conditioned mass of the specimen from the final mass. The buffering index K_fis the ratio of the sum of these components to the initial mass G₀.
Thus: $K_{f} = \frac{G_{1} + G_{2}}{G_{0}}$
2. The Drop Sorption Index, i_B
This test is described in Standard Test Specification BPI 3.2 ‘Testing of Textiles—Measurement of the Sorption Index i_B, Bekleidungsphysiologisches Institut E. V. Hohenstein, January 2003.
The test is carried out in an atmosphere of 20° C. and 65% relative humidity on fabric specimens approximately 2 cm×3 cm pre-conditioned for 24 hours. The specimens are fixed onto a flat table with double-sided tape with the side normally in contact with the skin facing upwards. A drop of distilled water of volume 42 μl is mechanically dispensed from a syringe located 5 cm above the centre of the test specimen at the rate of 13.76 μl/s. The sorption index i_Bis the time taken for this drop to be completely absorbed, that is, for the contact angle of the drop i_Bto fall to 0°. The drop rate is best monitored by a software-controlled video camera system.

Claims

1. A fabric including:

a) an inner face that is formed entirely from one or more than one hydrophobic yarn that has been treated to render it hydrophobic and said yarn or yarns are assembled over the inner face so that the inner face has a hydrophobicity that is substantially the same over the inner face; and

b) an outer face that in comparison to the inner face is hydrophilic and is formed at least in part by one or more than one hydrophilic yarn,

wherein the hydrophobic yarn or yarns are assembled so that liquid can penetrate the inner face and make contact with the hydrophilic yarn or yarns that form at least part of the outer face of the fabric and that, in turn, can draw liquid to the outer face of the fabric.

2. The fabric according to claim 1, wherein the hydrophobic yarn or yarns are assembled so that some sections of hydrophobic yarn in the inner face are separated by spaces through which liquid can penetrate.

3. The fabric according to claim 1, wherein hydrophobic yarn or yarns are assembled over the inner face of the fabric so as to form loops or floats on the inner face and thereby form said sections of hydrophobic yarn separated by spaces.

4. The fabric according to claim 1, wherein the spacing of the sections of hydrophobic yarn on the inner face of the fabric ranges from 0.01 to 25 mm in the wale or warp direction and ranges from 0.01 to 25 mm in the course or weft direction.

5. The fabric according to claim 1, wherein the spacing of the sections of hydrophobic yarn on the inner face of the fabric ranges from 0.1 to 2.5 mm in the wale or warp direction and ranges from 0.1 to 2.5 mm in the course or weft direction.

6. The fabric according to claim 1, wherein when worn against skin or located against an object, the hydrophobic yarn directly contacts the skin or object without hydrophilic yarn directly contacting the skin or object.

7. The fabric according to claim 1, wherein the hydrophilic and hydrophobic yarns include any one or a blend of the following types of fibers: a) man-made or synthetic fibers including, but not restricted to, polyester, polyurethane, polypropylene, polyamide, polyacrylonitrite, polyvinylchloride and regenerated cellulose; and b) natural fibers including proteinaceous fibers such as wool and hair and cellulosic fibers such as cotton.

8. The fabric according to claim 1, wherein the hydrophobic yarn or yarns are pre-treated with a hydrophobic agent prior to formation of the fabric.

9. The fabric according to claim 8, wherein fibers of the hydrophobic yarn or yarns are pre-treated with a hydrophobic agent when in the form of a yarn.

10. The fabric according to claim 1, wherein the outer face of the fabric is made from at least 50 percent hydrophilic yarn.

11. The fabric according to claim 1, wherein the outer face of the fabric is formed from at least 80 percent hydrophilic yarn.

12. The fabric according to claim 1, wherein the outer face of the fabric is formed from 100 percent hydrophilic yarn.

13. The fabric according to claim 1, wherein the hydrophobic yarn is pre-treated using an exhaust process.

14. The fabric according to claim 1, wherein at least one of the hydrophobic or hydrophilic yarns include cotton fibers and/or other types of cellulosic fibers.

15. The fabric according to claim 1, wherein at least one of the hydrophobic or hydrophilic yarns contains at least 50 percent cotton and/or other types of cellulosic fibers.

16. The fabric according to claim 1, wherein at least one of the hydrophobic or hydrophilic yarns contain at least 80 percent cotton and/or other types of cellulosic fibers.

17. The fabric according to claim 1, wherein both of said yarns are made entirely of cotton and/or other types of cellulosic fibers.

18. The fabric according to claim 1, wherein the ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 95:5 to 10:90 respectively.

19. The fabric according to claim 1, wherein the ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 60:40 to 80:20 respectively.

20. The fabric according to claim 1, wherein the hydrophobic and hydrophilic yarns are intermeshed in a manner whereby the hydrophilic yarns from part of a core or central region of the fabric and the outer face of the fabric.

21. The fabric according to claim 1, wherein the hydrophobic yarn is located at a distance ranging from 0.01 to 2.0 mm from an outer plane of the inner face of the fabric.

22. The fabric according to claim 1, wherein the hydrophobic yarn is located at a distance ranging from 0.1 to 1.0 mm from an outer plane of the inner face of the fabric.

23. The fabric according to claim 1, wherein the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.1 to 1.

24. The fabric according to claim 1, wherein the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.9 to 1.

25. The fabric according to claim 1, wherein the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 250.

26. The fabric according to claim 1, wherein the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 5.

27. A fabric including:

a) an inner face that is formed entirely from one or more than one hydrophobic yarn and said yarns are assembled over the inner face so that the inner face has a hydrophobicity that is substantially the same over the inner surface and is suitable for making the inside of a garment, wherein said yarns include cotton and/or other types of cellulosic fibers and have been pre-treated with a hydrophobic agent prior to formation of the fabric; and

b) an outer face that in comparison to the inner face is relatively hydrophilic such that liquid can be wicked through the inner face to the outer face, and wherein the outer face is made of yarns that include cotton and/or other types of cellulosic fibers.

28. The fabric according to claim 27, wherein the hydrophobic yarn is pre-treated with a hydrophobic agent prior to formation of the fabric.

29. The fabric according to claim 28, wherein fibers forming the hydrophobic yarn are pre-treated with a hydrophobic agent when in the form of a yarn.

30. The fabric according to claim 28, wherein the hydrophobic yarns be pre-treated using an exhaust process.

31. The fabric according to claim 27, wherein the outer face of the fabric is made from at least 50 percent hydrophilic yarns.

32. The fabric according to claim 27, wherein the outer face of the fabric is formed from at least 80 percent hydrophilic yarn.

33. The fabric according to claim 27, wherein the outer face of the fabric is formed from 100 percent hydrophilic yarn.

34. The fabric according to claim 27, wherein at least one of the hydrophobic or hydrophilic yarns contains 50 percent cotton and/or other types of cellulosic fibers.

35. The fabric according to claim 27, wherein at least one of the hydrophobic or hydrophilic yarns contains at least 80 percent cotton and/or other types of cellulosic fibers.

36. The fabric according to claim 27, wherein both of said yarns are made entirely of cotton and/or other types of cellulosic fibers.

37. The fabric according to claim 27, wherein the fabric has a ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 95:5 to 10:90 respectively.

38. The fabric according to claim 27, wherein the fabric has a ratio of hydrophilic to hydrophobic yarns on a mass basis ranges from 60:40 to 80:20 respectively.

39. The fabric according to claim 27, wherein the hydrophobic yarn or yarns are assembled so that sections of hydrophobic yarn in the inner face are separated by spaces through which liquid can penetrate and make contact with the hydrophilic yarn or yarns that form at least part of the outer face of the fabric and that, in turn, can draw liquid to the outer face of the fabric.

40. The fabric according to claim 39, wherein the hydrophobic yarns form loops or floats on the inner face and form said sections of hydrophobic yarn separated by spaces through which liquid can penetrate.

41. The fabric according to claim 39, wherein the spacing of said sections of hydrophobic yarn on the inner face of the fabric ranges from 0.01 to 25 mm in the wale or warp direction and ranges from 0.01 to 25 mm in the course or weft direction.

42. The fabric according to claim 39, wherein the spacing of said sections of hydrophobic yarn on the inner face of the fabric ranges from 0.1 to 2.5 mm in the wale or warp direction and ranges from 0.1 to 2.5 mm in the course or weft direction.

43. The fabric according to claim 27, wherein the hydrophobic and hydrophilic yarns are intermeshed in a manner whereby the hydrophilic yarns from part of a core or central region of the fabric and the outer face of the fabric.

44. The fabric according to claim 27, wherein the hydrophilic yarn is located at a distance ranging from 0.01 to 2.0 mm from an outer plane of the inner face of the fabric.

45. The fabric according to claim 27, wherein the hydrophilic yarn is located at a distance ranging from 0.01 to 1.0 mm from an outer plane of the inner face of the fabric.

46. The fabric according to claim 27, wherein when worn against skin or located against an object, hydrophilic yarn directly contacts the skin or object without hydrophilic yarn directly contacting the skin or object.

47. The fabric according to claim 27, wherein the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.1 to 1.

48. The fabric according to claim 27, wherein the fabric has a buffering capacity against liquid water K_f, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0.9 to 1.

49. The fabric according to claim 28, wherein the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 250.

50. The fabric according to claim 28, wherein the fabric has a drop sorption index i_B, which, when measured in accordance with a Hohenstein Institute standard test, ranges from 0 to 5.

51. A method of making a fabric that is capable of wicking liquid through an inner face to an outer face of the fabric, the method includes the steps of:

a) providing a hydrophilic yarn;

b) providing a hydrophobic yarn that has been pre-treated to render it hydrophobic; and

c) forming a fabric using said hydrophilic and hydrophobic yarns, wherein the yarns are assembled relative to each other such that the inner face of the fabric is made entirely from the hydrophobic yarn and liquid can penetrate the inner face and make contact with hydrophilic yarn that forms at least part of the outer face of the fabric and that, in turn, can draw liquid through the inner face to the outer face of the fabric.

52. The method according to claim 51, wherein some sections of hydrophobic yarn in the inner face are separated by spaces through which liquid can penetrate.

53. The method according to claim 51, wherein the hydrophilic and hydrophobic yarns include any one or a blend of the following types of fibers:

a) man-made or synthetic fibers including, but not restricted to, polyester, polyamide, polyurethane, polypropylene, polyacrylonitrile polyvinylchloride and regenerated cellulose; and

b) natural fibers including proteinaceous fibers such as wool and hair and cellulosic fibers such as cotton.

54. The method according to claim 51, wherein at least one of the hydrophobic or hydrophilic yarns include cotton fibers and/or other types of cellulosic fibers.

55. The method according to claim 51, wherein at least one of the hydrophobic or hydrophilic yarns contains at least 50 percent cotton and/or other types of cellulosic fibers.

56. The method according to claim 51, wherein at least one of the hydrophobic or hydrophilic yarns contains at least 80 percent of cotton fibers and/or other types of cellulosic fibers.

57. The method according to claim 51, wherein both of said yarns are made entirely of cotton and/or other types of cellulosic fibers.

58. The method according to claim 54, wherein step b) includes pre-treating the fibers with a liquor containing a hydrophobic agent and results in the hydrophobic agent being fixed to the fibers.

59. The method according to claim 58, wherein the pre-treatment involves contacting the fibers with the liquor using an exhaust process.

60. The method according to claim 58, wherein the pre-treatment is carried out at a temperature ranging from 10 to 110° C.

61. The method according to claim 58, wherein the pre-treatment is carried out at a temperature ranging from 20 to 70° C.

62. The method according to claim 58, wherein the pre-treatment is carried out at a starting temperature of 10° C. increasing at a rate ranging from 0.1 to 5.0 degrees per minute to a maximum of 110° C.

63. The method according to claim 58, wherein the pre-treatment is carried out at a starting temperature of 20° C. increasing at a rate ranging from 0.5 to 1.5 degrees per minute to a maximum of 70° C.

64. The method according to claim 58, wherein the hydrophobic agent used in the pre-treatment is any one or a combination of silicones, fluorochemicals, oils, latexes and hydrocarbons.

65. The method according to claim 58, wherein the hydrophobic agent included in the liquor is a fluoroacrylate polymer.

66. The method according to claim 58, wherein the liquor contains a concentration of electrolyte that minimises undesired deposition of hydrophobic agent or flocculation of hydrophobic agent and assists in achieving uniformity of the deposition of the hydrophobic agent throughout the yarns packages.

67. The method according to claim 58, wherein the liquid includes an electrolyte in the form of sodium sulphate or magnesium chloride.

68. The method according to claim 66, wherein the electrolyte concentration in the liquor ranges from 0 to 20 g/l.

69. The method according to claim 66, wherein the electrolyte concentration in the liquor ranges from 5 to 10 g/l.

70. The method according to claim 51, wherein the liquor includes a cross-linking agent for forming bonds between the hydrophobic agent and the cotton or other cellulosic fibers.

71. The method according to claim 70, wherein the cross-linking agent is heat activated and the method also includes a heat curing step in which the pre-treated yarn is heated to a temperature ranging from 50 to 230° C.

72. The method according to claim 70, wherein the curing step involves heating the pre-treated yarn to a temperature ranging from 110 to 190° C.

73. The method according to claim 71, wherein the heat curing step is carried out for a period ranging from 1 second to 40 minutes.

74. A method of making a fabric that is capable of wicking liquid through an inner face to an outer face of the fabric and the fabric includes two or more than two yarns that include cotton fibers and/or other types of cellulosic fibers, the method includes the steps of:

a) pre-treating cotton fibers and/or other types of cellulosic fibers of at least one of the yarns with a liquor containing a hydrophobic agent so as to impart hydrophobic properties to the fibers; and

b) forming a fabric from two or more yarns of which at least one yarn includes the cotton fibers and/or other types of cellulosic fibers pre-treated according to step a) and, wherein the yarns are assembled relative to each other such that the inner face of the fabric is made entirely from said yarn containing fibers pre-treated according to step a)and that the inner face of the fabric is hydrophobic compared to the outer face and has a hydrophobicity that is substantially the same over the inner face.

75. The method according to claim 74, wherein the step of pre-treating the cotton fibers and/or other cellulosic fibers with the liquor containing a hydrophobic agent results in the hydrophobic agent being fixed to the fibers.

76. The method according to claim 74, wherein step a) is carried out either before, during or after the cotton fibers and/or other types of cellulosic fibers are spun into a yarn.

77. The method according to claim 74, wherein at least one of the yarns contains at least 50 percent cotton and/or other types of cellulosic fibers.

78. The method according to claim 74, wherein at least one of the yarns contains at least 80 percent cotton and/or other cellulosic fibers on a weight basis.

79. The method according to claim 74, wherein the yarns include cotton fibers and/or other types of cellulosic fibers consist entirely of cotton fibers.

80. The method according to claim 74, wherein step a) involves submerging the cotton fibers in the liquor so that the hydrophobic agent is preferentially adsorbed onto the cotton fibers from the liquor.

81. The method according to claim 74, wherein step a) involves contacting the fibers with the liquor using an exhaust process.

82. The method according to claim 74, wherein step a) is carried out at a temperature ranging from 10 to 110° C.

83. The method according to claim 74, wherein step a) is carried out at a temperature ranging from 20 to 70° C.

84. The method according to claim 74, wherein step a) is carried out at a starting temperature of 10° C. increasing at a rate ranging from 0.1 to 5.0 degrees per minute to a maximum of 110° C.

85. The method according to claim 74, wherein step a) is carried out at a starting temperature of 20° C. increasing at a rate ranging from 0.5 to 1.5 degrees per minute to a maximum of 70° C.

86. The method according to claim 74, wherein the liquor includes any one or a combination of silicones, fluorochemicals, oils, latexes and hydrocarbons.

87. The method according to claim 74, wherein the hydrophobic agent included in the liquor is a fluoroacrylate polymer.

88. The method according to claim 74, wherein the hydrophobic agent is capable of forming covalent bonds to the surface of cotton and/or other types of cellulosic fibers treated according to step a).

89. The method according to claim 74, wherein the liquor contains a concentration of electrolyte that assists in achieving uniformity of the deposition of the hydrophobic agent throughout the yarn packages and minimises undesired deposition of polymer onto the treatment vessel or flocculation of hydrophobic agent.

90. The method according to claim 89, wherein the electrolyte is one or a combination of sodium sulphate or magnesium chloride.

91. The method according to claim 89, wherein the electrolyte concentration ranges from 0 to 20 g/l.

92. The method according to claim 89, wherein the electrolyte concentration ranges from 5 to 10 g/l.

93. The method according to claim 74, wherein liquor includes a cross-linking agent for forming bonds between the hydrophobic agent and the cotton or other cellulosic fibers.

94. The method according to claim 93, wherein the cross-linking agent is heat activated.

95. The method according to claim 93, wherein the method includes a heat curing step in which the pre-treated yarn is heated to a temperature ranging from 50 to 230° C.

96. The method according to claim 95, wherein the curing step involves heating the pre-treated yarn to a temperature ranging from 110 to 190° C.

97. The method according to claim 94, wherein the heat curing step is carried out for a period ranging from 1 second to 40 minutes.

98. The method according to claim 94, wherein the heat curing step is carried out over a time period that can range from 30 seconds to 20 minutes.

99. The fabric according to claim 1, wherein the outer face is laminated or joined to a waterproof and/or a windproof breathable membrane.