Moisture-management in hydrophilic fibers

Abstract

Provided is a fabric having improved moisture-management performance and being resilient to repeated washing, as well as a process for manufacturing the fabric. The process, employing consecutive steps of hydrophilization and hydrophobization, includes defatting cotton or cellulose fibers and their coating with silicone nanoparticles.

Claims

1. A process for manufacturing a cotton- or cellulose-containing fabric which exhibits improved moisture management compared to fabric not manufactured by the process, the moisture management further improving with repeated washing of the fabric, the process consisting of three consecutive steps: i) a hydrophilization step including treating cotton or cellulose fibers with a strongly defatting composition containing a mixture of a strong alkali and a detergent, the composition added to the fibers to clear the fibers of oily and waxy materials and other impurities, thereby decreasing hydrophobicity of the fibers and converting the fibers to super-hydrophilic filaments; ii) a hydrophobization step including treating the super-hydrophilic filaments resulting from carrying out step i) with a composition containing nanoparticles of silicone to encapsulate the super-hydrophilic filaments in silicone, wherein the treating includes immersing the super-hydrophilic filaments in a suspension comprising silicone nanoparticles bringing each individual super-hydrophilic filament of the super-hydrophilic filaments in contact with the silicone nanoparticles, thereby obtaining hydrophobized yarn; and iii) a production step including tightly weaving or knitting the hydrophobized yarn obtained from carrying out step ii) into a fabric, the tight weaving or knitting forming inter-fiber capillaries in the fabric; wherein the improved moisture management is essentially achieved by wicking moisture through the inter-fiber capillaries, which further open into channels as extra silicone particles inhabiting the inter-fiber capillaries wash-off with repeated washing of the fabric.

2. The process according to claim 1, wherein the fibers treated in step i) are cotton fibers.

3. The process according to claim 1, wherein the fibers treated in step i) are processed-cellulose fibers.

4. The process according to claim 1, further comprising weaving or knitting a synthetic fiber with the hydrophobized yarn in step iii) to produce a fabric combining the hydrophobized yarn with synthetic fibers.

5. The process according to claim 4, wherein the synthetic fiber woven or knitted with the hydrophobized yarn comprises polyamide or polyester.

6. The process according to claim 1, wherein the hydrophilization step i) includes immersing the fibers in the composition including strong alkali and detergent.

7. The process according to claim 1, wherein carrying out the steps i) and ii) results in encapsulating the super-hydrophilic filaments with a water-repellant surface of silicone nanoparticles, thereby obtaining hydrophobized yarn.

8. The process according to claim 1, wherein a cross section of each of the super-hydrophilic filaments is non-circular.

9. The process according to claim 8, wherein the cross section is a bean shape, thereby enabling formation of multiple channels between silicone-encapsulated super-hydrophilic filaments.

10. The process according to claim 1, further comprising treating the fabric produced in step iii) with additives selected from the group consisting of washing additives, bleaching additives, dying finishing additives, colorants, and finishing additives.

11. A cotton- or cellulose-containing fabric manufactured according to the process of claim 1.

12. The fabric of claim 11, wherein the fibers are cotton fibers.

13. The fabric of claim 11, wherein the fibers are processed-cellulose fibers.

14. The fabric of claim 11, further comprising a synthetic fiber combined with the hydrophobized yarn.

15. The fabric of claim 11, wherein the super-hydrophilic filaments encapsulated with nanoparticles of silicone formed by carrying out steps i) and ii) form open channels through which moisture is wicked from a wearer's skin to an outside of the fabric.

16. A textile article comprising the fabric of claim 11.

17. The textile article of claim 16, wherein the textile article is selected from the group consisting of apparel, garments, and clothing.

18. A process for manufacturing a cotton- or cellulose-containing fabric which exhibits improved moisture management compared to fabric not manufactured by the process, the moisture management further improving with repeated washing of the fabric, the process comprising consecutive steps of: i) a hydrophilization step including immersing cotton or cellulose fibers in a composition including strong base and detergent, the composition added to the fibers to clear the fibers of oily and waxy materials and other impurities, thereby decreasing hydrophobicity of the fibers and converting the fibers to super-hydrophilic filaments; ii) a hydrophobization step including immersing the super-hydrophilic filaments resulting from carrying out step i) in a suspension comprising silicone nanoparticles and bringing each individual super-hydrophilic filament of the super-hydrophilic filaments in contact with the silicone nanoparticles, thereby encapsulating the super-hydrophilic filaments in silicone and obtaining hydrophobized yarn; and iii) a production step including tightly weaving or knitting the hydrophobized yarn obtained in step ii) into the fabric exhibiting improved moisture management that further improves with repeated washing of the fabric.

19. A process for manufacturing hydrophobized yarn, the process comprising consecutive steps of: immersing cotton or cellulose fibers in a composition including strong base and detergent, the composition added to the fibers to clear the fibers of oily and waxy materials and other impurities, thereby decreasing hydrophobicity of the fibers and converting the fibers to super-hydrophilic filaments; and immersing the super-hydrophilic filaments in a suspension comprising silicone nanoparticles and bringing each individual super-hydrophilic filament of the super-hydrophilic filaments in contact with the silicone nanoparticles, thereby encapsulating the super-hydrophilic filaments in silicone and obtaining hydrophobized yarn.

20. A fabric manufactured from the hydrophobized yarn of claim 19.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other characteristics and advantages of the invention will be more readily apparent through the following examples, and with reference to the appended figures, wherein:

(2) FIG. 1A is a top view of the cotton fibers empolyed in an alternating concave/convex and flattened shape;

(3) FIG. 1B is a perspective view of the cottong fibers employed in an alternating concave/convex and flattened shape;

(4) FIG. 2 is Table I;

(5) FIG. 3 is Table II;

(6) FIG. 4 is Table III;

(7) FIG. 5 is Table IV;

(8) FIG. 6 is Table V; and

(9) FIG. 7 is Table VI.

EXAMPLES AND TEST RESULTS

(10) 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.

(11) 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.

(12) 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 C., Tumble Dry, that is, the fabrics were washed and dried repeatedly.

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

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

(15) 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.

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

(17) It is clear from Table I (FIG. 2), that all pre-treated fabrics pass the wicking test, and are not affected by repeated washing. Successful wicking, as the results in Table II (FIG. 3) 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.

(18) 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.sup.2 area coverage, and between 20% and 40% relative evaporation. The results are summarized in Tables III and IV below (FIG. 4 and FIG. 5).

(19) Table III 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.

(20) 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.

(21) 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 (FIG. 6 and FIG. 7) 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.

(22) 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.

(23) 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.