US 2979373 A
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United States Patent O LAUNDRY AIDS Theodore A. Seegrist, McLean, Va.
No Drawing. Original application Jan. 26, 1951, Ser. No. 208,051. Divided and this application May 13, 1955, Ser. No. 514,410
1 Claim. (Cl. 8-77) (Granted under Title 35, US. Code (1952), sec. 266) The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes throughout the world, without the payment to me of any royalty thereon.
This application is a division of my co-pending application Serial No. 208,051, filed January 26, 1951, now
Sodium carboxymethyl cellulose, hereinafter referre to as CMC, is valuable when suitably applied to fabrics, especially cotton goods, in connection with their laundering. It renders them more resistant to soiling and the soil more easily removed in subsequent washing.
CMC dissolves fairly easily, provided the water is brought into contact with the individual CMC particles; A body of the dry CMC, however, absorbs water slowly to form a jel. Lumps tend to form which become surface impervious due to swelling of the surface molecules, thus to hinder free penetration of the water. Such lumps are not easily broken up, and on standing become wetted through only after a considerable time.
If, however, the dry CMC is dispersed well in the water, it soon forms a clear solution of varying viscosity depending on the CMC concentration, but no definite demarcation between the dispersed and dissolved state can be made. Accordingly, the term disperse or dispersion as used herein is intended to include dissolve or solution where such meaning is applicable.
The invention of this application relates to the use of CMC as a fabric size in connection with laundering of the fabrics. For the purpose the CMC is incorporated into the final rinse water. Significant accomplishments of the invention include: rendering the CMC more readily dispersible in water; assuring use of the CMC in the final rinse water, the stage of laundering during which the CMC must be applied if its beneficial effects are to be obtained; stabilizing suspensions of insoluble bluing powder in the rinse water against settling out; and rendering it simple for the user to establish a suitable concentration of the CMC in the rinse water merely by observing the intensity of blue color in the rinse.
The object of rendering the CMC more easily dispersed is accomplished by mixing with the dry CMC a dry anticohesive or anti-adhesive, readily wettable, comminuted,
' solid materials, which should, of course, be inert or substantially inert toward the CMC.
When an insoluble bluing powder, such as an ultramarine, is used in admixture with the CMC, the suspension of thepowder in the rinse water is stabilized against settling out, a common defect with a bluing of this type.
If the bluing is used merely as an indicator to assure use of the CMC in the final rinse water, the proportion of bluing is not critical. However, it is preferable to so proportion the bluing that when the combined bluing and CMC are dispersed in water in such amount as to give a blue color of proper intensity for usual bluing rinse water or sizing purposes, the concentration of pure CMC will range about from .10 to 5.0 percent, thus to render it simple for the user to establish the suitable concentra- 2 tion. For example, if it is desired that the final rinsing size the fabric to obtain the anti-soiling benefits without noticeably, or only slightly, stiffening it, the proportion alone. I e
Dry mixing the CMC with other comminuted, solid materials of the aforementioned characteristics, for example laundry starch, also acts to render the CMC more dispersible. If it is desired that the starch be the predominant stiffening factor and the CMC performs only its anti-soiling function, the proportions may be such that when a starching medium is formed of desired body, the CMC will be present about from .10 to .60 percent. However, a much lower proportion of starch in the dry starch-CMC mixture is effective to aid inrendering the CMC more easily dispersed.
If the laundry starch used is of the insoluble-in-cold water type, it is necessary to boil the starch-CMC mixture in the water to effect a clear jel;
Of the following examples, Example I is detailed to the use of bluing powder with CMC, Example II to the use of laundry starch with CMC, while Examples III and IV exhibit the invention using both bluing powder and laundry starch.
Example I One part by weight of an insoluble bluing powder, an ultramarine, was thoroughly dry mixed with 12 parts of a technical grade of water-soluble CMC of about 60% pure CMC content.
The resulting mixture when dispersed in water in the amount of about 4 02., or heaping V2 pint measuring cup, per 10 gal. of water, an amount suificient for a rinse water batch for a'large family wash, gives a dispersion having a characteristic blue color for bluing purposes and having a CMC concentration of about 18 percent of pure CMC or .30 percent of the technical grade. The washed fabric may be rinsed therein in the usual manner with little change in the feel or stiffness of the fabric. Ironing is made easier. Such sized fabrics will resist soiling better than corresponding fabrics not so sized, and will wash more quickly and cleaner, in subsequent laundering.
The bluing-CMC dry mixture is comparatively easily dispersed in water. A homogeneous, fully jelled dispersion is formed in a few minutes by beating about 4 oz. of the mixture, in as little as /2 gallon of cold water, and more easily if the water is heated. Such dispersion is readily poured when hot, but viscous when cold. The concentrated dispersion can be readily mixed with more water to form a suitable rinse water.
The dispersion may also be formed by merely stirring the bluing-CMC drymixture in any desired amount of Y cold water and allowing the mixture to stand until the CMC is fully swelled. Overnight or longer standing is sufficient. Complete homogeneity is obtained subsequently by mild stirring for a few minutes in a desired amount of water.
The dispersions thus formed are well stabilized against settling out of the suspended bluing powder. With the higher CMC concentration, no noticeable settling occurs on long standing. Even when diluted to give the .30 percent concentration before mentioned, settling occurs Patented Apr. 11, 1961 in several hours, to a much smaller degree than with a corresponding amount of bluing powder alone.
In order to obtain CMC concentrations in the final sizing medium over the .10 to 5.0 percent range before mentioned with a characteristic blue color, the proportion of bluing powder to technical CMC in the .dry bluing: CMC mixture should vary with 1 part bluing powder about from 6 to 240 parts of the CMC.
Example 11 One part by measure of technical water-soluble CMC was thoroughly dry mixed with 4 parts of a powdered commercial laundry starch (one which dissolved easily upon about 1 minute stirring in boiling water).
This mixture can be pasted in a small amount of water and then dispersed in hot water by efiiciently stirring while gradually adding the hot water. One to 3 heaping tablespoonfuls of the mixture per quart of water gives a starching medium suitable for light to heavy starching purposes and the concentration of technical CMC will range about from .25 to 1.0 percent.
Example 111 4 a in this event aid in making the CMC more easily dispersed.
Example IV Four parts by volume of technical water-soluble CMC and 1 part of a powdered, cold water soluble, commercial, laundry starch were thoroughly dry mixed.
The mixture disperses easily with mild stirring in cold water to give a sizing medium of desired concentration.
A similar mixture, but containing a sufiicient amount of insoluble bluing powder to impart a desired blue color, is also easily dispersed.
A process comprising dispersing a dry mixture of an insoluble bluing powder, laundry starch and CMC in water to give a CMC concentration of about from .10 to 5.0 percent based on the water with the bluing powder suspended therein, the amount of bluing powder being such as to give ablue color of proper intensity for bluing rinse water purposes, rinsing a washed fabric therein, and drying the rinsed fabric.
Condensed Chemical Dictionary, 4th ed., Turner-Reinhold Pub. Corp., N.Y., 1950, pages 142 and 603.
Chemical Formulary, vol. 1, Bennett, Van Nostrand, N.Y., 1933, page 174.