US2991538A - Method of blending textile fibers and resulting yarns and fabrics thereof - Google Patents

Description

2,991,538 METHOD OF BLENDING TEXTILE FIBERS AND RESULTING YARNS AND FABRICS THEREQF James A. Hendley, Box 177, Stanley, N.C. No Drawing. Filed Apr. 16, 1958, Ser. No. 728,780 Claims. ((31.28-75) This invention relates to the manufacture of fibrous material, such as textile fabrics which may be woven, non-woven, knitted or the like, to incorporate in the material a predetermined percentage of permanently blued fibers and thereby produce a fibrous wihite material having permanently blued characteristics.

It is well known that white fabrics, even though completely white immediately after bleaching, tend to develop an undesirable yellowish appearance with age. This yellowness is caused by oxidation, soap or detergent particles left in the fabric by repeated launderings and exposure to Weather or heat and this yellowness cannot always be completely removed by subsequent bleaching or scouring treatment.

In order to conceal the yellowness in the fabric it has been the practice for many years to incorporate in the fabric a blue pigment, such as ultramarine or Alkali blue or other types of fugitive blue dyestufi each time the fabric is laundered. This blue pigment tends to neutralize the yellowness in the fabric and make the same appear to be a brighter white. This bluing of the fabric during the laundering operation is eifective but has several disadvantages, the most important of which is that the blue pigment added is not permanent and it is also extremely difficult to determine the proper amount of blue to add to absorb the yellowness then present in the articles being laundered. Permanent bluing would be very desirable in drip-dry or wash-and-wear fabrics where bluing during laundering is not contemplated.

Another known method of suppressing the yellowness in fabric includes the use of optical brightening agents which are usually more or less colorless substances having the ability to absorb light in the ultraviolet part of the spectrum and emit a violet or bluish-green fluorescence. Thus, the yellowing effect is destroyed or absorbed by the blue light emitted by the fluorescent blue substance added to the fabric to give the fabric a true white appearance. The principal disadvantage of this optical brightening agent is that it is rapidly removed after laundering of the fabric and has a very poor resistance to chlorine bleaching and to the effect of strong light. While many of the optical brightening agents are suitable for use with cellulosic fibers and have recently been considerably improved as to their fastness when laundering, these products are unsuitable for use with other fibers having only a small afiinity for the brighteners.

With the foregoing in mind, it is the primary object of this inveniton to incorporate a permanent blueness to fabrics by the addition of a predetermined percentage of permanently blued fibers so that any yellowness developing in the fabric will be absorbed or neutralized by the blue fibers. In the case of textile fabrics, which are formed of individual threads, the permanently blued fibers may be added to the threads as they are produced or the permanently blued fibers may be incorporated in the fabric in the desired percentage by any other means. In the case of non-Woven fibrous material, such as cotton batting and the like, the desired percentage of permanently blued fibers may be blended in with the other fibers before the fibers are joined together to produce the fibrous web.

It is another object of this invention to provide a permanently blued fibrous material incorporating permanently blued fibers which form a part of the body of the tas es Patented July 11, 1961 material and are sufliciently permanent that they will remain constant after many launderings and their color will not be affected by bleaching, ordinary aging, heat, strong light or the like. 7

In accordance with the present invention it has been found that solution-dyed or dope-dyed :viscose rayon staple may be easily blended with a wide range of other fibers and is sufiiciently permanent to maintain its color over long periods of time and use. The fastness of this rayon staple is excellent under all normal hazards such as bleaching, laundering, heat, light and age. The use of a blue rayon staple is also advantageous because it will readily blend with other fibers.

The percentage of blue fibers added to the fabric is usually relatively small when compared to the percentage of undyed fibers in the material and the percentage of each fiber will vary according to the intensity of the blue dyed fibers. The term undyed fibers hereinafter used throughout the specification and claims is used to differentiate the white fibers, both bleached and unbleached, from the small percentage of permanently blued fibers.

It is preferred that the percentage of blue dyed fibers be kept relatively low, within the range of about onequarter percent to about seven percent of the total weight of the fabric. The percentage of blue fibers used will vary with the shade of blue, the type of fiber and the result desired, it being obvious that a pale or light blue fiber can be used in a greater percentage and achieve the same results. While this method of permanently bluing white fabrics is particularly useful in the production of sheets, shirts, blouses, towels and the like, it is by no means restricted to these uses and may be equally applicable to rope, sewing thread and other articles.

The following specific example is given by way of illustration only without any intention to restrict the invention in any way.

EXAMPLE I In this example, the blue fibers used are solution-dyed viscose rayon staple manufactured by Courtaulds (Alabama) Incorporated, of Mobile, Alabama, under their trade name of Coloray and bearing their color classification of crystal blue. In this example the blue staple is added to and intermingled with natural unbleached and undyed cotton staple at the blending feeder and the two fibers are processed through the usual cotton processing equipment such as picking, carding, drawing, spinning and winding to produce a combination thread having the desired percentage of blue fibers therein. In this case the combination thread includes eight percent blue rayon staple and 92 percent cotton staple. The blue staple may be introduced to the cotton staple later in the processing such as during carding or drawing if desired. The combination thread thus formed is then woven into a fabric with the combination thread having the blue staple and cotton staple therein being used only for the filling thread during weaving while the warp threads are formed of percent undyed cotton staple.

The fabric is then woven with 146 cotton warp ends per inch and 74 picks of combination filling threads per inch so that the finished fabric contains 97.308 percent cotton staple and 2.692 percent blue rayon staple by weight of the fabric. Each of the threads, both the cotton warp thread and the combination filling thread, are 47/1 count. This is one construction for shirt material and may be bleached, secured and finished in the usual manner. After finishing, the fabric has a definite bluewhite appearance which is very desirable in a white fabric.

Samples of this particular permanently blued fabric have been woven and the colors which are reflected have been tested and recorded by a Gardner Multipurpose Reflectometer made by Gardner Laboratories, Inc., Bethesda,

Chart A lWhiteness Yellowness Blueness 100% cotton fabric (unlaundered)- Cotton and blue fiber fabric (11nlaundered) The numbers under whiteness indicate the percentage of whiteness as compared to the whiteness of magnesium oxide (MgO) which is equal to 100 when tested on this reflectometer. It will be noted that while the brightness of the combination fabric is not as great as the whiteness of the 100 percent cotton fabric, there is no yellowness in the combination fabric and the blueness indicated is desirable in a pure white.

Each of the above samples were laundered for eight one-hour periods and were agitated dry between each wash. The samples were then ironed flat and the reflectometer test again applied to each sample. This laundering was carried out by using oleate flakes (sodium oleate) which is pure soap, and it might be noted that during these eight washings the samples were continuously agitated and would probably compare to about thirty home launderings. The light reflecting properties of these two samples after laundering as above described are compared in the Chart B below.

Chart B whiteness Yellowness Blueness 100% cotton fabric (laundered) 55. 8 7. 64 Cotton and blue fiber fabric (laundered) 71. 0 1. 23

It is interesting to note, by comparing Charts A and B, that the reflected whiteness of the combination fabric actually increases after laundering and the reflected whiteness of the 100 percent cotton fabric decreases considerably after laundering while the reflected yellowness increases. Thus, with each laundering the combination fabric, having the blue fibers therein, tends to yellow but the blue fibers present absorb or neutralize the yellow reflections of the incident light to thereby decrease the blueness but increase the whiteness at the same time.

EXAMPLE II Permanently blued cloth may also be woven which will have the same color reflecting properties as that of Example I by combining permanent blue fibers in both the filling and warp threads. In this case the percentage of blue fibers added to the warp and filling threads is decreased by approximately half the amount used when used in the filling thread only. Thus, the filling and warp threads would each contain about 2.5 percent blue fibers so that the woven cloth would contain approximately 2.5 percent blue rayon staple.

EXAMPLE HI Satisfactory permanently blued samples have also been produced by combining other fibers such as rayon staple with cotton staple and the permanently blued staple in either the filling threads, warp threads or both. A satisfactory fabric has been produced with thread containing one percent light blue dyed rayon staple fiber, 29 percent viscose rayon staple and 70 percent cotton staple in the filling yarn only and this thread woven into a muslin sheeting fabric. Of course, fibers other than those named may be utilized to form a permanently blued fabric as long as they have characteristics enabling them to be permanently blued. It is to be understood that the term permanently blued as used. herein is meant to include not only solution or injection dyed fibers but fibers colored by any type of treatment whereby the blueness is sufliciently permanent that it will not fade appreciably during the normal life of the fabric.

Other fibers other than that cited in Example I will also produce satisfactory results, for example, Colorspun rayon manufactured by American Viscose Corporation bearing their color identification Number 3006 has been used with satisfactory results. Other synthetic fibers which may be treated to impart blueness thereto and blended with non-blue fibers to produce a fibrous material which is permanently blued include: acetate, nylon, Dacron, Acrilon and Orlon. The exact shade of blue required may vary with the type of goods produced, the percentage of blend and in some cases it may be desirable to have a blue which is slightly on the reddish side.

It is thus seen that there has been provided a permanently blued fabric and method of producing the same wherein permanently dyed blue fibers are combined with the undyed fibers so that after bleaching the dyed blue fibers neutralize any yellowness to maintain the whiteness of the fabric through many washings. The permanently blued fibers in the fabric present a desirable over-all bluewhite fabric when first finished and with aging and laundering, the blueness of the fabric decreases as it absorbs greater amounts of yellowness, thus actually increasing the amount of white light reflected by the fabric. The permanently blued fabric produced in accordance with this invention will maintain its whiteness over a long period without applications of bluing or other special treatments with each laundering.

The blued fibers in a fabric or yarn produced in accordance with this invention are dispersed or intermingled with the other fibers in such a manner that their presence is not obvious by a casual observation of the fabric or yarn, but may be seen by close examination or by magnification of the material. The blued fibers in the material act to absorb some of the yellow light rays normally reflected by the material to create the optical effect of a brighter white material.

In the specification there have been set forth several embodiments of the invention and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. A permanently blued white textile fabric comprising interwoven warp and filling threads, each of said warp threads being formed entirely of undyed fibers, each of said filling threads being formed of approximately eight percent permanently blued fibers combined with 92 percent undyed fibers, said blued fibers being randomly intermingled with said undyed fibers of said filling thread whereby said blued fibers neutralize yellowness ordinarily reflected from the undyed fibers of both the warp and filling threads of said fabric for improving the white appearance of the fabric.

2. A method of improving the whiteness of a textile fabric to reduce the normal yellowness reflected by the fabric under ordinary visible light which comprises the steps of processing undyed fibers to form warp threads, blending approximately eight percent permanently blued fibers with 92 percent undyed fibers to form filling threads, and weaving said warp and filling threads to form a fabric having approximately 146 warp threads per inch and approximately 74 filling threads per inch whereby the blued fibers of the filling threads are randomly dispersed throughout the fabric and act to neutralize the yellowness ordinarily reflected from the undyed fibers of both the warp and filling threads for improving the whiteness of the fabric.

3. A textile fabric comprising interwoven warp and filling threads, said fabric including permanently blued fibers and undyed fibers randomly dispersed therein, the

5 percentage of said blued fibers in said fabric being within the range of one-quarter of one percent to seven percent of the total weight of said fabric, said fabric presenting a predominately white appearance, and said blued fibers in said fabric neutralizing yellowness ordinarily reflected from the undyed fibers of said fabric for improving the white appearance of said fabric.

4. A textile fabric comprising interwoven warp and filling threads, said warp and filling thread seach including undyed fibers, at least one of said warp and filling threads comprising permanently blued fibers combined with undyed fibers, said blued fibers being randomly intermingled with said undyed fibers insaid one thread, the percentage of said blued fibers in said fabric being within the range of one-quarter of one percent to seven percent of the total weight of said fabric, said fabric presenting a predominately white appearance, and said blued fibers in said fabric neutralizing yellowness ordinarily reflected from the undyed fibers of the warp and filling threads of said fabric for improving the white ap pearance of said fabric.

5. A textile fabric comprising permanently blued fibers and undyed fibers randomly dispersed therein, the percentage of said blued fibers in said fabric being within the range of one-quarter of one percent to seven percent of the total weight of said fabric, said fabric presenting a predominately white appearance, and said blued fibers in said fabric neutralizing yellowness ordinarily reflected from the undyed fibers of said fabric for improving the white appearance of said fabric.

References Cited in the file of this patent UNITED STATES PATENTS 128,267 Wilkinson June 25, 1872 689,559 Meyer Dec. 24, 1901 2,519,347 Burgess Aug. 22, 1950 FOREIGN PATENTS 1,874 Great Britain of 1871 3,000 Great Britain of 1871 673,728 Great Britain June 11, 1952