Elastane with reduced visibility

Abstract

The present invention provides elastic fiber compositions with reduced show-through effect. Also provided are methods for producing and using these compositions.

Description

Technical Field

[0001] The present invention relates to elastic fiber compositions containing carbon black pigment, white opacity enhancer, and inorganic pigment or acid dye receptor and exhibiting reduced grin-through effect in stretch fabrics and methods for their production and use. Background Art

[0002] Fabrics containing spandex are often combined with another companion yarn, such as, but not limited to, cotton, nylon, polyester, wool, or acrylic. These fabrics are typically dyed with dyes whose chemical structure is specifically designed to be compatible with the particular companion yarn.

[0003] In some cases, the elastic fiber is knitted, plated, or woven into a fabric with a companion yarn prior to dyeing and is therefore also exposed to this dyeing process. However, because the dyeing chemistry is not intended to be formulated for elastic fibers having different chemical properties and linear densities or filament values ​​than the companion yarn, the resulting color shade on the elastic fiber may be different from the color shade of the companion yarn.

[0004] In other cases, the companion yarn is dyed before the fabric is made, and the elastic fiber does not participate in the dyeing process at all. In these cases, the elastic fiber will also have a different color tone from the companion yarn in the fabric.

[0005] When a knitted fabric containing stretch fibers is stretched, it opens up the structure and makes the stretch fibers more visible to the observer. When this happens, and when the stretch fibers have a different hue or sheen, the fabric has a very different, and often undesirable, appearance than when the fabric is in its relaxed state. This effect is known in the art as 'show-through.'

[0006] Elastane manufacturers have made various attempts to reduce the see-through effect.

[0007] For example, attempts have been made to make spandex fibers more compatible with the dyes used on accompanying yarns. These "dyeable" spandex fibers are disclosed, for example, in published U.S. applications No. US2005 / 0165200, WO 2009 / 084815, and EP 2157215A1. However, these efforts are limited to improving dyeability with nylon acid dyes, and matching the shade of dyed spandex fibers with dyed nylon can be challenging due to the different dextrose values ​​of each fiber and the varying gloss levels they may possess.

[0008] A second approach used commercially is to add black pigment to the spandex to make it less visible in the fabric, see for example US 2006 / 0210794. This approach is limited to fabrics intended to have dark shades, and they may still have an undesirable show-through or shine effect when stretched.

[0009] Fiber manufacturers have also attempted to minimize the shimmer or shiny aspect of the show-through by using opacity enhancers such as titanium dioxide in the fibers. This effectively increases the opacity of the spandex and increases the white appearance of the fiber, but samples in fabrics still exhibit the undesirable show-through effect in practical applications.

[0010] There is a need for an elastic fiber that significantly reduces or eliminates the see-through effect in stretch fabrics. Summary of the Invention

[0011] The present invention relates to an elastic fiber that exhibits significantly reduced show-through effect in stretch fabrics and methods for its production and use.

[0012] Thus, one aspect of the present invention is directed to a spandex composition comprising spandex, carbon black pigment, a white opacity enhancer, and an inorganic pigment and / or an acid dye receptor.

[0013] Another aspect of the present invention relates to filaments and fibers for producing stretch fabrics with reduced grin.The fibers are produced from an elastic fiber composition comprising elastic fiber, carbon black pigment, white opacity enhancer, and inorganic pigment and / or acid dye receptor.

[0014] Another aspect of the present invention relates to a method for reducing the see-through effect of elastic fibers in stretch fabrics. In this method, carbon black pigment, white opacity enhancer, and inorganic pigment and / or acid dye receptor are added to an elastic fiber composition.

[0015] Yet another aspect of the present invention is directed to an article comprising, at least in part, a composition or fiber comprising elastomeric fiber and carbon black pigment, a white opacity enhancer, and an inorganic pigment and / or an acid dye receptor. DETAILED DESCRIPTION

[0016] The present invention relates to elastic fiber compositions having reduced show-through in stretch fabrics and methods for producing these compositions and using these compositions in fiber and filament production and articles.

[0017] The elastic fiber composition of the present invention comprises elastic fiber, carbon black pigment, white opacity enhancer and inorganic pigment or acid dye receptor.

[0018] The term "stretch fiber" is used herein in its generic sense to refer to man-made fibers in which the fiber-forming substance is a long-chain synthetic polymer comprising segmented polyurethane and / or polyurethane urea. Stretch fiber compositions are well known in the art and can include many variations, such as those disclosed in Monroe Couper, Handbook of Fiber Science and Technology: Vol. III, High Technology Fibers Part A. Marcel Dekker, INC: 1985, pp. 51-85.

[0019] Carbon black pigment is added to the elastic fiber. In one non-limiting embodiment, a low level of carbon black pigment is added. As used herein, "low level" refers to about 25 ppm to about 200 ppm of carbon black pigment.

[0020] A white opacity enhancer is also added to the elastic fiber. In one non-limiting embodiment, the white opacity enhancer is titanium dioxide. In one non-limiting embodiment, about 0.01 to about 1% by weight of the white opacity enhancer is added. The opacity enhancer is titanium dioxide or any other material with a refractive index greater than 1.8 at 632.8 nanometers. In one non-limiting embodiment, about 0.01 to about 1% of titanium dioxide is added.

[0021] In one non-limiting embodiment, the elastic fiber composition further comprises an inorganic pigment. Non-limiting examples of useful inorganic pigments include hydrotalcite, magnesite, hydromagnesite, magnesium carbonate, calcium carbonate, magnesium oxide, magnesium hydroxide, and combinations thereof. In one non-limiting embodiment, the inorganic pigment is added in an amount of about 1% to about 10% by weight.

[0022] In an alternative non-limiting embodiment, the spandex composition further comprises an acid dye acceptor. In a non-limiting embodiment, the acid dye acceptor is from the family of tertiary amines and quaternary ammonium salts, or a combination thereof. In a non-limiting embodiment, the acid dye acceptor comprises from about 10 to about 50 milliequivalents of active nitrogen per kilogram of fiber.

[0023] The present invention also provides filaments and fibers produced from these elastic fiber compositions having reduced blow-through.Methods for producing such filaments and fibers are well known in the art and need not be described in detail herein.

[0024] Additionally, the present invention provides articles comprising, at least in part, the compositions, filaments, or fibers of the present invention.

[0025] In one non-limiting embodiment, the article is a fabric.In one non-limiting embodiment, the fabric is a stretch fabric.

[0026] The elastic fiber content of the fabric containing the elastic fiber of the present invention can be from about 0.5 weight percent (wt.%) to about 40 wt.%, based on the weight of the fabric. For example, a circular knit fabric containing elastic fiber can contain from about 2 wt.% to about 25 wt.% elastic fiber, leg wear containing elastic fiber can contain from about 1 wt.% to about 40 wt.% elastic fiber, a raschel fabric containing elastic fiber can contain from about 10 wt.% to about 40 wt.% elastic fiber, and a warp knit tricot containing elastic fiber can contain from about 14 wt.% to about 22 wt.% elastic fiber.

[0027] The fabrics of the present invention may further comprise a companion fabric. Non-limiting examples of companion fabrics include cotton, nylon, polyester, wool, or acrylic. The elastic fibers of the present invention can be produced by dry spinning, wet spinning, or melt spinning. The fiber properties are not limited to circular knit processes. Any fabric production method, such as warp knitting, seamless knitting, hosiery and sock knitting, and woven fabric processes, is suitable for use with the fibers of the present invention.

[0028] The present invention also provides a method for using the elastic fiber composition to reduce the see-through effect of fabrics containing elastic fibers.

[0029] As demonstrated herein, these spandex compositions provide a dull sheen and grayness to spandex, resulting in a significantly reduced or eliminated show-through effect. Furthermore, combination with dye additives allows for further reduction of show-through without adversely affecting light to rich dark shades.

[0030] While not wishing to be bound by theory, it is believed that the grayscale created by the low levels of carbon black helps dilute the visual contrast of the accompanying yarn dye absorbed or bound to the spandex relative to the color depth that the accompanying yarn dye would exhibit if dispersed into a standard, uncolored spandex. Furthermore, it is believed that the addition of specific amounts of white opacity enhancers helps reduce hue changes caused by oxidative yellowing of the fiber, although the white color of these additives is contrary to the intended effect of carbon black pigment. Furthermore, it is believed that the inorganic pigment specifically reduces the fiber's gloss, which is associated with the fiber's shine when exposed to an observer after stretching a fabric containing spandex, while the acid dye receptors are believed to enhance the color on the spandex, providing a rich, dark hue.

[0031] All patents, patent applications, test procedures, priority documents, articles, publications, manuals, and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with the present invention and for all jurisdictions in which such incorporation is permitted.

[0032] The following examples illustrate the present invention and its capabilities for use. The present invention is capable of other and different embodiments, and its several details can be modified and / or substituted in various obvious aspects without departing from the spirit and scope of the present invention. Therefore, the examples are to be considered as illustrative in nature and not restrictive.

[0033] Examples

[0034] The knitted fabrics listed in Table 1 were produced as circular knits tubing on a Lawson knitting unit (Lawson-Hemphill Company, Model "FAK.") For items 1-21, one charge of 40 denier spandex was knitted to form a 100% spandex fabric. For items 22-27, one end of 40 / 34 flat nylon was plaited with one end of 40 denier spandex to form a co-knit. The Lawson tubular samples were washed at 80°C for 30 minutes with 1 g / L soda ash and 1 g / L Domoscour LFE-810.

[0035] Table 1

[0036]

[0037]

[0038] Table 2 plots the color depth of various knitted fabrics made from 100% spandex fibers and containing the additive formulations indicated in columns 2, 3, and 4. L* is an internationally recognized color depth scale with values ​​ranging from 0 to 100. The lower the L value, the darker the color. As the carbon black loading increases, the L* value of the spandex article decreases. This holds true even in the presence of inorganic pigments and white opacity enhancers. As shown in the figure, increasing the TiO2 loading also causes an increase in the L* value. See Table 2.

[0039] Table 2

[0040] Reference Number Carbon black (ppm) Inorganic pigments (%) White opacity enhancer (%) L*(natural color, 100% spandex) 1 0 0 0 88 2 50 0 0 77 3 100 0 0 69 6 150 0 0 69 7 200 0 0 65 8 250 0 0 65 9 0 1.5 0.17 87 10 60 1.5 0.17 71 11 80 1.5 0.17 66 12 100 1.5 0.17 67 15 100 1.5 0 61 16 100 1.5 0.32 66 17 100 1.5 0.64 71

[0041] Knitted fabrics made from 100% spandex fibers and containing the additive formulations indicated in columns 2, 3, and 4 of Table 3 were optically brightened using Phorwite CLE (1.5%) at pH 5 and 98°C for 40 minutes. The optically brightened fabrics were then exposed to combustion gas fumes under AATCC test conditions. The ΔCIE value is the change in CIE whiteness value after exposure to combustion gas fumes under AATCC test conditions. The lower the change, the lower the impact of the combustion gases on the resulting color change (e.g., less yellowing is visible in L100 articles compared to CC or C100 values). The presence of carbon black causes a decrease in the initial CIE whiteness and a significant decrease in the ΔCIE between the initial and final whiteness values. See Table 3.

[0042] Table 3

[0043]

[0044] Knitted fabrics made from 40 / 34 flat nylon and 40 denier spandex with the additive formulations indicated in columns 2, 3, and 4 of Table 4 were optically brightened using Phorwite CLE (1.5%) at pH 5 and 98°C for 40 minutes. The optically brightened fabrics were exposed to combustion gas fumes under AATCC testing conditions. The ΔCIE value is the change in CIE whiteness value after exposure to combustion gas fumes under AATCC testing conditions. Similar trends were observed in the optically brightened nylon / spandex blends as in the 100% spandex fabrics. See Table 4.

[0045] Table 4

[0046]

Claims

1. An elastic fiber composition comprising an elastic fiber, a carbon black pigment in a range of 50-200 ppm, a white opacity enhancer, and an inorganic pigment, wherein the white opacity enhancer is titanium dioxide, wherein the inorganic pigment is selected from the group consisting of hydrotalcite, magnesite, hydromagnesite, magnesium carbonate, calcium carbonate, magnesium oxide, magnesium hydroxide, and combinations thereof, and 0.17 to 0.32 weight percent of the white opacity enhancer is added.

2. An elastic fiber composition comprising an elastic fiber, a carbon black pigment in the range of 50-200 ppm, a white opacity enhancer, an inorganic pigment, and an acid dye receptor, wherein the white opacity enhancer is titanium dioxide, wherein the inorganic pigment is selected from the group consisting of hydrotalcite, magnesite, hydromagnesite, magnesium carbonate, calcium carbonate, magnesium oxide, magnesium hydroxide, and combinations thereof, and 0.17 to 0.32 weight percent of the white opacity enhancer is added.

3. The elastic fiber composition according to claim 1, wherein 1 to 10 wt% of an inorganic pigment is added.

4. The spandex composition of claim 2, wherein the acid dye receptor is from the family of tertiary amines and quaternary ammonium salts or a combination thereof.

5. The elastic fiber composition according to claim 2, wherein the acid dye acceptor is added in an amount of 10 to 50 milliequivalents of active nitrogen per kilogram of fiber.

6. A filament or fiber comprising the composition according to any one of claims 1 to 5.

7. An article comprising, at least in part, a composition according to any one of claims 1 to 5 or a filament or fiber according to claim 6.

8. The article of claim 7 which is a fabric.

9. The article of claim 8 which is a stretch fabric.

10. The article of claim 8 or 9, wherein the fabric further comprises a companion yarn.

11. The article of claim 10, wherein the companion yarn is selected from cotton, nylon, polyester, wool or acrylic or any combination thereof.

12. A method for reducing the see-through effect of elastic fibers in fabrics, the method comprising producing the elastic fibers from the elastic fiber composition according to any one of claims 1 to 5.

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