Field of the Invention

The present invention relates to a process for imparting to hydrophilic

fibers less absorbing of moisture properties, and improved moisture- management in yarns and fabrics thereof. More specifically, the present

invention relates to cotton or man-made cotton or cellulose fibers within

yarns or fabric constructions, where their moisture transmission throughout is improved.

Background of the Invention

Moisture -management rapidly accumulates increased interest in high-tech textile industry as an important factor in recreational as well as

customary garments and apparels. The need for fast drying type fabrics,

especially for athletic purposes, has so far been satisfied with the use of

synthetic hydrophobic materials that do not absorb moisture. However,

the ability to control perspiration absorption, transport, and evaporation

off skin tissue through apparels, made of natural hydrophilic materials,

especially ones as cotton, to the atmosphere enables their use in areas

traditionally governed by the synthetic fabrics.

Moisture-management is defined in the Journal of Textile and Apparel, Technology and Management, Vol. 2, Issue 3, Summer 2002, as "the controlled movement of water vapor and liquid water (perspiration) from

the surface of the skin to the atmosphere through the fabric". Although

mostly referred to perspiration, this term may be more broadly related to

release of liquid, secreted from different body organs through skin tissue,

and its subsequent transport and removal.

Cotton fabrics are well known to impart a more pleasant feeling upon

contact with skin tissue, and are mostly preferred due to either their

natural origin or other superior qualities over synthetic fibers. However,

being essentially of hydrophilic nature, they are known to absorb liquids

secreted through skin tissue, and release them only too slowly into the

atmosphere, especially when a wearer is being engaged with excessive

physical activity. These features produce a heavy apparel when wet, which

imparts an uncomfortable wet and sticky sensation to the wearer.

Additional effects are the limiting of one's motion, and induction of a cold

feeling during recess.

Several approaches are known to date in processing hydrophilic fabrics,

e.g.. cotton, into fast drying type. Drying rate of cotton fabrics with

reduced thickness turned to be equal to that of polyester fabrics. Other solutions employed the use of blends of cotton and synthetic fibers, e.g., cotton/polyester, cotton/nylon, or cotton/polypropylene, hydrophobic backing layers as silicone, or waxes on the fabric side, which is close to the skin, or scouring, bleaching, and finishing of 100% cotton fabrics (for the last approach see, Moisture Management: Myths, Magic and

Misconceptions, William A Rearick, Vikki B. Martin, and Michele L. Wallace, Cotton Incorporated, Cary, NC).

Moisture-management in hydrophilic fabrics is translated into a wicking process of the liquid absorbed, in which a spontaneous transport of the

liquid is driven through pores and spaces in the fabric by capillary forces. The surface tension of the liquid causes a pressure difference across the curved liquid-air (vapor) giving a liquid movement. Wicking is also affected by the morphology of the fiber surface, and may be affected by the shape of the fibers. The rate of wicking is affected by the size and geometry of the capillary spaces between fibers. Therefore, wicking can be improved by changing the fiber surface by absorption of surfactant.

Although the aforementioned detailed reference relates mostly to cotton, the inventive concept of the present invention applies equally to other raw materials, from which man-made fibers, yarns, and various types of fabrics, garments, and apparels may be produced. Cotton and cellulose, the latter also having hydrophilic tendency and good water absorption similar to that of cotton, are good examples of raw materials from which moisture-management improved man-made fibers may be produced. Such man-made fibers are, therefore, good potential candidates for the fabrication of improved moisture-management textile products according to the teaching of the present invention, while sustaining their other virtues essentially unaffected. In its broader scope, the present invention,

therefore, relates also to man-made yarns and fabrics and end-uses

thereof, which are made of essentially hydrophilic materials, and which

are of improved moisture-management qualities according to the teaching

of the present invention.

It is therefore an object of the present invention to provide a process for

the manufacture of yarns and fabrics with improved moisture-

management performance.

Still another object of the present invention is to provide a process for the

manufacture of fabrics possessing improved performance of moisture-

absorption, moisture-transportation, and moisture-evaporation.

Still another object of the present invention is to provide a process for the

manufacture of fabrics with improved wicking effect.

Still another object of the present invention is to provide a process for the

manufacture of modified encapsulated fibers within a fabric.

Still another object of the present invention is to provide a nano technology process for the manufacture of silicone-encapsulated fibers in a fabric, where the silicone encapsulation is of particulate form of nano-scale size, and therefore the encapsulation being applied include nano chemistry process.

In still another object of the present invention the fabrics and fibers thus

manufactured are of surface area and morphology that while being silicon-

encapsulated improved, their moisture-management and wicking are

improved.

Still another object of the present invention is to provide silicon-

encapsulated fibers in a fabric, where the encapsulation includes a nano

technology chemistry.

Still another object of the present invention is to provide fabrics

comprising silicone-encapsulated fibers.

In still another object of the present invention the fabrics comprising

silicone-encapsulated fibers for moisture-management improvement

comprise woven, non-woven, textured, or knitted forms.

Still another object of the present invention is to provide garment and

textile articles comprising silicone-encapsulated fibers imparting more

comfortable sensation upon use, and improved moisture-management, wicking, transportation, and evaporation.

In still another aspect of the present invention the fibers, yarns, fabrics, and end-uses textiles thereof, are essentially made of hydrophilic

materials, which are good water absorbents. Particularly, the fibers,

yarns, and fabrics of the present invention are either cotton or man-made

cotton or cellulose fibers, yarns and fabrics, respectively.

In one preferred embodiment, the present invention provides a process for

the manufacture of silicon-encapsulated cotton yarns and fabrics with

improved moisture-management performance, the moisture-management being expressed in moisture-absorption, moisture-transportation , i.e.,

wicking, and moisture -evaporation.

In a second preferred embodiment, the present invention provides a

process for the manufacture of silicone-encapsulated man-made cotton or cellulose yarns and fabrics with improved moisture-management

performance, the moisture-management being expressed in moisture-

absorption, moisture -transportation, i.e., wicking, and moisture-

evaporation.

Summary of the Invention

The present invention provides the benefits of both a fabric comprising

modified textile fibers, imparting a pleasant sensation upon contact with skin tissue, and improved moisture-management performance, essentially alleviating uncomfortable perspiration and heat off the skin.

Moisture- or water- management in hydrophilic yarns and fabrics, especially in hydrophilic cotton or man-made cotton or cellulose yarns and fabrics, is achieved through wicking of excessive moisture through the fibers themselves and through pores in between them. Wicking in hydrophobic silicone -encapsulated fibers is carried-out through capillaries formed between individually encapsulated fibers. That is, each fiber is encapsulated with a moisture-repellant material, the fibers are tightly bound together, and wicking does not take place through the fibers themselves. Especially, treatment of either cotton or man-made fibers with

silicone, which is a hydrophobic material, and silicone encapsulation is therefore of double purpose; preventing penetration of moisture inside the fibers themselves, for example during body perspiration, or in any other form of secretion of water, aqueous solutions, suspensions, dispersions and the like at the same time ensuring moisture-transportation and evaporation through capillary wicking in between the fibers.

Furthermore, a commonly known drawback in most contemporary improved fabrics in this field is the gradual, continuous deterioration in

moisture-management during use, and especially after repeated washings. Contrary to that, the process of the present invention, and the fibers, and fabrics thereof, offer at least sustaining moisture-management performance level during use, and in most cases even its improvement, especially after repeated washings. The latter phenomenon results due to washing-off of extra silicone particles inhabiting the inter-fiber capillaries, thus opening them, and allowing better breath ability, and wicking of moisture absorbed. This fact sets an important advantage of the process of the present invention over other processes for the manufacture of fibers and fabrics thereof known in this field, demonstrating a more resilient, life-extended fiber, fabrics, textile, and garment articles comprising it.

In accordance with the nano technology process of the present invention, encapsulation treatment of the fibers is carried-out with water-repellant nano chemistry silicone. Preferably, this encapsulation is conducted essentially by bringing each individual fiber in contact with silicone nano- particles, also termed nano-silicone. Preferably, this contact takes place by immersing the fibers in particulate silicone suspension, thus ensuring maximal silicone coverage of each fiber surface area. Since silicone is a hydrophobic material, moisture penetration into the cotton fibers is thus prevented, while capillary wicking process takes over in moisture transportation off the skin, the concurrent evaporation, and as a result a cool and comfortable feeling.

A preferable feature of the fibers, aiding in the wicking process, is their surface morphology. As is demonstrated in Figure 1, the cotton fibers employed, may be of an alternating concave/convex and flattened shape. The fibers morphology may be alternatively described as that of bean shape, where the fibers take a slightly flat and twisted shape. Such morphology forms multiple conduits, in which moisture-air surface tension increases, vertical capillarity of moisture is enhanced, and as a result wicking process is accelerated.

Fabrics, textiles, apparels, and garments of the present invention may further comprise other types of fibers in combination with the modified cotton or man-made cotton or cellulose fibers. In one embodiment of the present invention the fabrics comprise cotton fibers, which are

incorporated with Lycra in a volume ratio of 1:10.

AJl the above and the characteristics and advantages of the invention will be further explained through the following illustrative and non-limitative

examples.

Examples and Test Results

Wicking tests of untreated and treated cotton fabrics have been conducted

under two standard test methods, i.e., Drop Test, and Vertical Wicking, the latter being according to both M&S (Marks and Spencer) and Nike standard test.

The results, presented in the following Tables, refer either to time-

dependent advance of moisture in the capillary channels of a cotton fabric, in accordance with the Vertical Wicking test method, or to time-dependent

area coverage advance of the moisture in the fabric, measured close to starting and advanced time points, in accordance with the test method of

Drop Test. The Drop Test also includes percentage measurements of moisture evaporation at a pre-determined time-point.

In both tests, the fabrics were further tested for sustaining wicking performance level after repeated washes. It should be mentioned in this regard, that although it is common practice to test fabrics up to between 10 and 20 wash rounds, the tests of the fabrics of the present invention continued further to up to 30 wash rounds. Another point is that each wash round included 30 cycles at 40 ⁰ C, Tumble Dry, that is, the fabrics were washed and dried repeatedly.

Absorbency test were conducted in accordance with Nike absorbency test method and standard, and were aimed at measuring the susceptibility of

- l i ¬ the fabric to take in and retain a liquid (usually water) within the pores and construction of the fabric. Absorbency rate of a drop was measured in five different areas, and in both front and back surfaces of the fabric. The minimal time period required for determining absorbency in fabrics was set to 30 seconds.

Analysis of the results is provided in accordance with the following Tables I-VI.

Fabrics made essentially of cotton fibers or cotton/Lycra combinations with known relations, were tested for moisture-management before and after treatment. Table I herein summarizes time-dependent results obtained for pre-treated fabrics under Nike standard test. According to this standard, the advance of moisture through the fabric essentially measures wicking; this is done by the vertical test at the fabric length 'L' and the fabric width 'W. As is noted in the caption below, a time- dependent distance of 15 cm in maximal 30 minutes time interval is a minimal requirement for quality assurance.

Table I - FABRIC SAMPLES BEFORE TREATMENT

VERTICAL WICKING NIKE PF3-2001

K ⁾

Table II - FABRIC SAMPLES AFTER TREATMENT VERTICAL WICKING NIKE PF3-2001

U)

I

The results obtained were further compared to those of treated fabrics comprising silicone-encapsulated cotton fibers or silicone-encapsulated cotton/Lycra fiber combinations.

It is clear from Table I, that all pre-treated fabrics pass the wicking test, and are not affected by repeated washing. Successful wicking, as the results in Table II demonstrate, is observed also in the treated fabrics, in most cases accompanied by an exceptional improvement with increasing wash rounds, contrary to ordinary decrease in performance.

Wicking test was also conducted under Drop Test standard, and moisture evaporation test as well. Same fabrics that were tested for wicking as shown in Tables I and II, were tested here, only according to this standard

the area coverage of moisture in the fabrics was measured at close to starting and end time points. Evaporation was measured at a time point of 10 minutes after moisture-absorbance, and relative to the wet fabric weight. The minimum requirements for successfully passing this test were between 600 to 1000 mm ² area coverage, and between 20% and 40% relative evaporation. The results are summarized in Tables III and IV below.

WICKING & EVAPORATION DROP TEST

Table UI -FABRIC SAMPLES BEFORE TREATMENT M&S TEST P 136 A

Ui

Table IV- WICKING & EVAPORATION DROP TEST

FABRIC SAMPLES AFTER TREATMENT M&S TEST p-136A

Os

STANDARD

M&S

EVAPORATION: 20% -

40%

WICKING : 600-1000 sq. mm

Table TII demonstrates that all pre-treated fabrics pass successfully the wicking test, while essentially and mostly do not comply with the minimum sufficient level of evaporation. In contrast, the same type of

fabrics comprising silicone-encapsulated cotton fibers or combinations of silicone-encapsulated cotton fibers/Lycra pass successfully both wicking and evaporation tests. The exceptional successful and even improved results of both wicking and evaporation tests are repeated under this standard as well. It is therefore straightforwardly concluded that this phenomenon is inherent to those fabrics that comprise silicone- encapsulated cotton fibers.

It should also be noted that the combination of both good wicking and good evaporation performances results in the desired goal of the present invention, as well as the one in the field of fast-drying type hi-tech fabrics. That is, fabrics that comprise silicone-encapsulated cotton fibers in accordance with the teaching of the present invention, provide both moisture-absorbance and fast moisture-transport and moisture-release.

Absorbency tests were conducted to assure the minimum requirement for standard moisture -absorption rate, substantially being set to minimum time interval of 30 seconds. Tables V and VI herein, present the pre- treated and treated fabrics, respectively. As can be clearly seen, silicone-

encapsulation does not negatively affect the susceptibility to moisture of the fabrics.

In summary, according to the results presented hereinabove, the novel fabrics of the present invention essentially and substantially demonstrate excellent moisture-management performance, which is also durable with time and repeated use. The fabrics of the present invention are, therefore, excellent materials for various garment and textile applications, and for various daily, regular, recreational, or many other applications.

While examples of the invention have been described for purposes of illustration, it will be apparent that persons skilled in the art can carry out many modifications, variations and adaptations, without exceeding the scope of the claims.

ABSORBENCY

AATCC 79

vo

ABSORBENCY

AATCC 79 Table VI-FABRIC SAMPLES AFTER TREATMENT

O