WO2004000049A1

WO2004000049A1 - A multi-layered fabric

Info

Publication number: WO2004000049A1
Application number: PCT/AU2003/000766
Authority: WO
Inventors: Barry Victor Holcombe; Ian Blanchonette; John Anthony Rippon; Ronald James Denning; David John Evans
Original assignee: Commonwealth Scientific and Industrial Research Organization CSIRO
Current assignee: Commonwealth Scientific and Industrial Research Organization CSIRO
Priority date: 2002-06-19
Filing date: 2003-06-19
Publication date: 2003-12-31
Anticipated expiration: 2004-12-19
Also published as: AUPS304802A0

Abstract

The present invention relates to a multi-layered fabric that is particularly suitable for making sports garments. The fabric is characterized in that it includes: a first layer including cellulosic fibres that can be used to form the inside face of a garment; a second layer made entirely from non-cellulosic fibres, the second layer being positioned relative to the first layer such that liquid is able to be transferred from the first layer to the second layer, wherein the fibres of the second layer have a surface energy greater than the surface energy of the fibres of the first layer. The fibres of the second layer therefore have a greater affinity for liquid than the first layer such that the wicking gradient of the fabric increases from the first layer to the second layer and thereby draws sweat away from the person wearing a garment made from the fabric.

Description

A MULTI-LAYERED FABRIC

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a multi-layered fabric containing cellulosic fibres. More particularly, the present invention relates to a multi-layered fabric which is capable of transferring liquid from the skin of a person wearing the fabric to an outside face or layer of the fabric to thereby keep the person cool and dry. The present invention therefore relates to a multi-layered fabric that is particularly suitable for making sports garments .

There are numerous varieties of prior art fabrics in this field. A typical example of such a fabric is disclosed in European patent application EP 777,978. In particular, EP 777,978 discloses a two layered fabric in which the denier of the yarn forming the inner layer of the fabric is greater than the denier of the yarn forming the outer layer of the garment. In principle, the fabric draws liquid away from the skin of the person wearing the fabric by means of a capillary action in the sense that the spaces between the fibres form capillaries through which liquid is transferred.

The term "denier" has a well-known meaning and represents the mass per unit length of a yarn. Generally speaking, lower denier yarns contain fibres having a smaller diameter and thus smaller capillaries are formed between the fibres, which result in a greater wicking potential . Another example is the fabric disclosed in US patent 5,787,503 which includes two independent layers sewn together using a polygon-shaped quilt stitch to form insulating pockets between the layers of the fabric . The outer layer of the fabric comprises a blend of wool and acrylic yarn, whereas the inner layer comprises a polyester or acrylic such that the hydrophilicity of the inner layer is greater than the hydrophilicity of the outer layer. It is also disclosed that the yarn of the outer layer may be treated with a TEFLON compound to artificially increase the hydrophobicity of the outer layer . In contrast, there are also several fabrics such as those sold under the trade marks TRANSTEX, TRANSPOR and SPORTWOOL, which comprise a two layer fabric in which the outer layer has a greater hydrophilicity than the inner layer of the fabric. These fabrics rely, at least to some extent, on a strongly hydrophilic outer layer drawing the liquid away from a less hydrophilic or even hydrophobic inner layer.

More generally, the hydrophilic or hydrophobic characteristic of a fibre is a function of the surface energy of a fibre. It has also been previously disclosed that the surface energy of a fibre can be increased so as to become more hydrophilic, that is, the fibre is more readily wetted. Techniques that have been previously disclosed to increase the surface energy and hydrophilicity of a fibre include: i) modifying the fibre surface, such as by hydrolysis of polyesters or oxidation of wool; or ii) applying a hydrophilic finishing agent such as polyester co-polymers including Zelcon 5126, Hydrolon, Stev-Tex MMA, Milease T, polysiloxanes including Ultraphil HSD, Sandotur HV, Sandoperm, Reactosil RWS, and ethoxylated carboxylic acid derivatives including Dilasoft RS, and Valsof .

However, cellulosic fibres, unlike most other fibres, have a very high surface energy once naturally occurring waxes coating the fibre have been removed, which normally occurs during finishing processes such as scouring. The very high surface energy of -cellulosic fibres is the basis for their very good wicking potential. Unfortunately, fabrics manufactured from cellulosic fibres attract water so strongly and in such quantities that they tend to form liquid bridges across to the skin of a person wearing fabric made from cellulosic fibres. This causes the familiar "wet cling" whereby garments adhere to the skin when saturated with liquid or sweat.

It is therefore an object of the present invention to provide an alternative multi-layered fabric containing cellulosic fibres that alleviates this problem.

SUMMARY OF THE INVENTION

The present invention is described below with reference to three different, yet equally important aspects, namely a multi-layered fabric, a method for manufacturing the fabric, and a garment.

According to the present invention there is provided a multi-layered fabric including: a first layer suitable for forming the inside face of a garment, the first layer having at least 90% cellulosic fibres; and a second layer made entirely from non-cellulosic fibres, the second layer being positioned relative to the first layer such that liquid is able to be transferred from the first layer to the second layer; wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

According to the present invention there is also provided a multi-layered fabric including: a first layer suitable for forming the inside face of a garment, the first layer including cellulosic fibres; and a second layer made entirely from non-cellulosic fibres, the second layer being positioned relative to the first layer such that liquid is able to be transferred from the first layer to the second layer; wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer. In other words, it is a characteristic of the fabric of the present invention that the wicking gradient, that is the affinity of the fabric for liquid, increases from the first layer to the second layer.

Throughout this specification, the term "non- cellulosic fibres" includes but is not limited to, proteinaceaus fibres such as wool, synthetic fibres, polyolefin fibres such as polypropylene or polyethylene fibres, polyester fibres, nylon fibres, polyvinyl fibres, polyurethane fibres, acetate fibres, mineral fibres and silk.

Throughout this specification, the term "cellulosic fibres" includes but is not limited to, cotton, linen, rayon, jute and hemp.

Preferred features of the multi-layered fabric of the present invention will now be described.

Depending on the nature of the fibres used in the second layer, it is possible that the first layer may comprise 100% cellulosic fibres. However, in view of cellulosic fibres having a surface energy that is higher than most commonly available fibres, there is a need to ensure that the surface energy of the second layer is greater than the surface energy of the first layer. The manner by which the surface energy of the first and second layers is adjusted to the required level may be one of many. A description of two preferred techniques for adjusting the surface energy of the first layer is set out below. According to one preferred technique, the first layer is a blend of cellulosic fibre and another fibre of lower surface energy than the cellulosic fibre,- such as polyester or polypropylene fibres .

According to another technique, which may or may not be used in conjunction with the first technique, it is preferred that the cellulosic fibres of the first layer be treated with a material so as to reduce the surface energy of the fibres. Suitable materials for treating the fibres include hydrophobic polymers selected from the chemical families of fluorochemicals, silicones, polyolefins, polyurethanes, polyesters, latexes or copolymers of these families; oils and waxes; hydrophobic metal salts; cellulose cross-linking agents; compounds capable of forming an ester linkage with the hydroxyl groups of cellulose; combinations of cross-linking agents with any of the aforementioned materials; and mixtures of any of the aforementioned materials. It is even more preferred that the material used have both hydrophilic and hydrophobic moeities to control the surface energy of the fibre and other functional groups for binding the compound to the cellulosic fibre. As mentioned previously, scoured cellulosic fibres have very high surface energies relative to most other generic fibre classes. The main application of the materials listed above is in rainwear. Their function is to make the surface energy of cotton and other fibres as low as possible so that fabrics manufactured with these fibres repel liquid water. Ideally the present invention involves reducing the surface energy of the cellulose inner layer below that of the fibre used for the outer face, but not so far as to make it completely water repellent.

Although it is possible that the materials for treating the cellulosic fibres can be applied to a fabric in finished form, these materials may be applied by any known method such as padding, foam application, lick rollers, dip-hydro, spraying, exhaustion, printing or doctor blade.

According to several embodiments of the present invention, the material can be applied to the cellulosic fibres prior to the fibres being processed into a finished fabric. The two aspects of yarn treatment and controlled reduction of surface energy are central to the successful realisation of the present invention. In particular, materials that are currently available that can be used by the above methods are sold under the trade names Flexichem SA1093A and Flexichem PF1091B.

According to an embodiment of the present invention, it is preferred that the material applied to the cellulosic fibres be a silicone compound and the amount of silicone compound bonded to the fibres ranges from 0.01 to 5.00% of the weight of the fibres.

According to an another embodiment, it is preferred that the amount of silicone compound bonded to the fibres ranges from 0.1 to 2.00% of the weight of the fibres . An advantage provided by the present invention is that cellulosic fibres typically absorb moisture vapour into the inner regions of the fibre as humidity rises and release moisture vapour as humidity falls. This characteristic of cellulosic fibres is known as vapour buffering and is generally independent of the surface energy or wicking ability of the fibre. Vapour buffering is often measured in terms of saturation regain, which is a representation of the total vapour capacity of the fibre. It is a preferred feature of the fabric of the present invention that the regain of the first layer be greater than 6.5% at 65% humidity and 21 °C. In contrast, the regain of most non-cellulosic fibres is below 6%. Accordingly, a person wearing fabric according to the present invention may experience the fabric being able to "breathe" better than comparative fabrics.

A further useful comparison used to compare fibres and, more particularly, the characteristics of a fabric is a test known as the liquid drop or wicking spread test. Generally speaking a wicking spread test involves the steps of: holding the fabric to be tested in a horizontal plane with the inner layer of the fabric facing upwardly; placing a drop of water mixed with a dye onto the inner layer of the fabric and allowing the water to be fully absorbed by the fabric; and finally, measuring the diameter of the stained areas on the first and second layers . It is a preferred that the wicking spread diameter ratio of the second to first layers be at least 2 : 1.

It is also preferred that the fibres of the first layer have a diameter greater than the diameter of the fibres of the second layer. It is even more preferred that the intimate contact between the first and second layers involve fibres of the first and second layers being intermeshed.

According to the present invention there is also provided a method of making a multi-layered fabric including the steps of: forming a first layer from at least 90% by weight of cellulosic fibres; forming a second layer entirely of non-cellulosic fibrous material; positioning the first and second layers relative to each other so that liquid is able to be transferred from the first layer to the second layer; and wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

According to the present invention there is also provided a method of making a multi-layered fabric including the steps of: forming a first layer containing cellulosic fibres; forming a second layer entirely of non-cellulosic fibrous material; positioning the first and second layers relative to each other so that liquid is able to be transferred from the first layer to the second layer; and wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer. Preferred features of the methods of the present invention described in the preceding two paragraphs will now be described in detail.

It is preferred that the method also includes the step of controlling the surface energy of the first layer so that it is less than the surface energy of the second layer .

It is preferred that the step of controlling the surface energy of the fibres of the first layer includes treating the cellulosic fibre with a material so as to reduce the surface energy of the fibres.

It will be appreciated by a person skilled in the art of the present invention that the step of controlling the first surface energy may be carried out concurrently, consecutively or disjunctively with the other steps of the method of the invention. For example, a yarn, silver, roving or any other intermediate in yarn or fibre preparation may be treated so as to control the surface energy of the first layer. Alternatively, it is also within the scope of the invention that the step of controlling the surface energy includes treating the cellulosic fibres when in a finished knitted or woven fabric .

Accordingly, it is preferred that the step of controlling the surface energy of the fibres of the first layer includes treating the cellulosic fibres with a material prior to fibres being processed into a fabric.

Examples of suitable materials for controlling the surface energy of the fibres of the first layer, including hydrophobic polymers, have been described in more detail above. The material may be applied to the fibres of the first layer using any of the following known techniques: padding, foam application, lick rollers, dip-hydro, spraying, exhaustion, printing or doctor blade. It is possible that the step of controlling the surface energy of the fibres of the first layer may also include combining either treated or untreated cellulosic fibres with another fibre of lower surface energy.

A person skilled in the art would appreciate that the fabric and/or the layers within the fabric of the present invention may be formed from any technique including knitting, weaving or any other form of non-woven interlacing. In addition, forming the first or second layer may simply be accomplished by one of said layers being provided by a third party to a manufacturer of the fabric.

According to the present invention there is also provided a garment including the multi-layered fabric described above.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

According to a preferred embodiment of the present invention, a multi-layered fabric can be manufactured as a knitted structure, wherein the knitted structure is formed from separate layers made wholly or predominantly of a single yarn. Each layer provides either the inner or outer face of the fabric and may be held together by tucking the yarn forming the inner layer into the outer layer, or visa versa. Alternatively, a third binder yarn may be tucked across both the inner and outer layers of the fabric .

More particularly, the fabric can be knitted using a 22 gauge circular knitting machine in which the inner face may be knitted on all dial needles of the knitting machine and the outer face may be knitted on all cylinder needles . The inner and outer layers can be held together by tucking a 15 denier continuous filament nylon binder yarn on all needles, both inner and outer faces, on every course. The outer face consists of hydrophilic polyester

'Coolmax' polyester staple fibre yarn, single ply, in 45s English cotton count, knitted on all face needles. The inner face consists of single ply cotton yarn, 40s English cotton count. Prior to knitting, the cotton yarn is bleached using a standard recipe and subsequently treated with a hydrophobic silicone compound, namely Flexichem SA1093B, at 40°C and pH 6.5 for a period of 30 minutes in order to reduce the surface energy of the cotton yarn. The silicone compound used to treat the cotton can range from 0.01% to 5 % on weight of the cotton. Preferably, 0.5 % on weight of the cotton is used. Instead of, or in addition to treating the cotton yarn with the silicone compound, the cotton fibres of the yarn for the inner face may be blended with a fibre having a lower surface energy, such as polyester or polypropylene . After knitting, the fabric is scoured in warm water in the presence of a detergent to remove any knitting waxes.

In another embodiment of the present invention, the surface energy of the cotton of the fabric described in the first embodiment is determined by controlling the application of the scouring and bleaching step so as to retain some of the hydrophobic wax naturally present on the cotton.

A range of favourable test results has been obtained on the fabric. For instance the wicking characteristics of the fabric have been measured by a wicking spread test.

Specifically, the wicking spread test involved holding a section of the fabric to be tested in a 15cm diameter embroidery hoop under light tension with the inner face of the fabric facing upwardly and placing a 20μl drop of liquid onto the inner face of the fabric using a micropipette. In order for the liquid in the layers to be readily visible, the drop of liquid discharged from the pipette onto the fabric was a sample of liquid made from one litre of distilled water mixed with 500mg of Allura red food dye. Once the drop had been placed in the inner face it was absorbed by the fabric for a period of 30 seconds, and subsequently the size of the stained areas on the inner and outer faces of the fabric were measured. The technique used to measure the size of the stained areas involved taking two perpendicular diameter measurements of the stain, with one diameter measurement being along the longest axis of any ellipticity of the stain.

The wicking spread test was repeated on five samples of the fabric of the preferred embodiment. The diameter ratio of the wicking spread of the outer face to that of the inner face was equal to or greater than 2.0 : 1 on all occasions.

The wicking characteristics of a control fabric were also measured using the wicking spread test. The only difference between the fabric of the preferred embodiment and the control fabric was that the scoured cotton yarn of the control fabric was left untreated in the sense that it was not treated with the hydrophobic silicone compound. Set out below is a summary comparing the wicking characteristics of the fabric according to the preferred embodiment and the control fabric.

In addition, tests have been conducted which confirmed that cotton yarn treated with the hydrophobic silicone compound has negligible effect on the moisture regain of the fibres. Specifically, a comparison was carried out on single jersey fabrics knitted on a 14 gauge knitting machine using cotton yarns treated with a hydrophobic silicone compound in a manner similar to the preferred embodiment and a control fabric made of cotton yarns that were left untreated.

The method involved determining the regain of each fabric by placing a sample of fabric into a controlled atmosphere of 21°C and 65% relative humidity for a minimum period of 4 hours . The fabric was then placed into a tared weighing bottle and the total weight recorded.

The sample of fabric was then placed in an oven for a period of 1 hour at 100°C and subsequently sealed and placed in a desiccator to cool for a period of 30 minutes. The dried sample was then transferred to a second, freshly-tared weighing bottle, reweighed and the mass of the fabric determined.

The regain of the fabric was then calculated based on the mass difference between the conditioned and dried states and expressed as a percentage of the dry mass. The test was carried out on three samples of the fabric according to the preferred embodiment and three samples of the control fabric. A summary of the results obtained for the fabrics following this method are set out below:

Any reference to prior publications or prior disclosures in this specification is not to be taken as an admission that this material forms part of the common general knowledge of a person skilled in the art in Australia or in any other country.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A multi-layered fabric including: a first layer suitable for forming the inside face of a garment, the first layer having at least 90% cellulosic fibres; and a second layer made entirely from non-cellulosic fibres, the second layer being positioned relative to the first layer such that liquid is able to be transferred from the first layer to the second layer; wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

2. A multi-layered fabric including: a first layer suitable for forming the inside face of a garment, the first layer including cellulosic fibres; and a second layer made entirely from non-cellulosic fibres, the second layer being positioned relative to the first layer such that liquid is able to be transferred from the first layer to the second layer; wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

3. The multi-layered fabric according to claim 1 or

2, wherein the first layer is a blend of cellulosic fibre and another fibre of lower surface energy than the cellulosic fibre.

4. The multi-layered fabric according to any one of claims 1 to 3, wherein the cellulosic fibres of the first layer are treated with a material so as to reduce the surface energy of the fibres.

5. The multi-layered fabric according to claim 4, wherein the material used for treating the cellulosic fibre is any one of fluorochemicals, silicones, polyolefins, polyurethanes, polyesters, latexes or copolymers of these families; oils and waxes; hydrophobic metal salts; cellulose cross-linking agents; compounds capable of forming an ester linkage with the hydroxyl groups of cellulose; combinations of cross-linking agents with any of the aforementioned materials; and mixtures of any of the aforementioned materials.

6. The multi-layered fabric according to claim 4, wherein the material used has both hydrophilic and hydrophobic moeities to control the surface energy of the fibre and other functional groups for binding the material to the cellulosic fibre.

7. The multi-layered fabric according to claim 4, wherein the material used for treating the cellulosic fibre is a silicone containing compound and the amount of silicone containing compound bonded to the fibres ranges from 0.01 to 5.00% of the weight of the fibres.

8. The multi-layered fabric according to claim 7, wherein the amount of silicone containing compound bonded to the fibres ranges from 0.1 to 2.00% of the weight of the fibres .

9. The multi-layered fabric according to any one of the preceding claims, wherein the regain of the first layer is greater than 6.5% at 65% humidity and 21°C.

10. The multi-layered fabric according to any one of the preceding claims, wherein the wicking spread diameter ratio of the second to first layers be at least 2 : 1.

11. The multi-layered fabric according to any one of the preceding claims, wherein the fibres of the first layer have a diameter greater than the diameter of the fibres of the second layer.

12. A method of making a multi-layered fabric including the steps of: forming a first layer from at least 90% by weight of cellulosic fibres; forming a second layer entirely of non-cellulosic fibres; positioning the first and second layers relative to each other so that liquid is able to be transferred from the first layer to the second layer; and wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

13. A method of making a multi-layered fabric including the steps of: forming a first layer containing cellulosic fibres; forming a second layer entirely of non-cellulosic fibres; positioning the first and second layers relative to each other so that liquid is able to be transferred from the first layer to the second layer; and wherein the fibres of the second layer have a surface energy greater than the surface energy of fibres of the first layer.

14. The method according to claim 12 or 13, further including the step of controlling the surface energy of the first layer so that it is less than the surface energy of the second layer.

15. The method according to claim 14, wherein the step of controlling the surface energy of the fibres of the first layer includes treating the cellulosic fibre with a material so as to reduce the surface energy of the fibres .

16. The method according to claim 14 or 15, wherein the step of controlling the surface energy of the fibres of the first layer includes treating the fibres with a material prior to the fibres being processed to form a fabric .

17. The method according to claim 15, wherein the material for treating the cellulosic material is any one of fluoroche icals, silicones, polyolefins, polyurethanes, polyesters, latexes or copolymers of these families; oils and waxes; hydrophobic metal salts; cellulose cross- linking agents; compounds capable of forming an ester linkage with the hydroxyl groups of cellulose; combinations of cross-linking agents with any of the aforementioned materials; and mixtures of any of the aforementioned materials.

18. The method according to claim 15, wherein the material for treating the cellulosic material has hydrophilic and hydrophobic moeities to control the surface energy of the fibre and other functional groups for binding the material to the cellulosic fibre.

19. The method according to claim 15, wherein the material used for treating the cellulosic fibre is a silicone containing compound and the amount of silicone containing compound bonded to the fibres ranges from 0.01 to 5.00% of the weight of the fibres.

20. The method according to claim 15, wherein the amount of silicone containing compound bonded to the fibres ranges from 0.1 to 2.00% of the weight of the fibres .

21. The method according to any one of claims 12 to 19, wherein the regain of the first layer be greater than 6.5% at 65% humidity and 21°C.

22. The method according to any one of claims 12 to 21, wherein the wicking spread diameter ratio of the second to first layers is at least 2 : 1.

23. The method according to any one of claims 12 to 22, wherein the fibres of the first layer have a diameter greater than the diameter of the fibres of the second layer .

24. The method according to claim 14, wherein the step of controlling the surface energy of the first layer includes blending the cellulosic fibre with another fibre of lower surface energy than the cellulosic fibre.

25. A garment including the multi-layered fabric according to any one of claims 1 to 12.