US 3925230 A
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United States Patent [191 Koepfle et al.
[ 1 NON-CAKING LAUNDRY SOUR  Inventors: Frank Xavier Koepfle; Herbert Edward Grote, both of Cincinnati, Ohio  Assignee: The Procter & Gamble Company, Cincinnati, Ohio  Filed: Dec. 26, 1973  App]. No.: 428,512
 US. Cl. 252/136; 8/77; 252/142; 252/385  Int. C1. ...CllD 7/10; C1 1D 7/14; D06M 1/18  Field of Search 252/135, 136, 142, 385;
 References Cited UNITED STATES PATENTS 2,141,589 12/1938 Bishop 1. 8/77 2,275,049 3/1942 Keller 252/385 2,426,836 9/1947 McCoy 1 v 1 1 252/136 2,846,401 8/1958 McCarthy 252/385 X 1 Dec. 9, 1975 OTHER PUBLICATIONS B. Levitt: Oils, Detergents and Maintenance Specialties, Vol. 2, Chemical Publishing C0,, New York, 1967, pp, 156-157.
Primary Examiner-Dennis E. Talbert, .lr.
Assistant Examiner-Dennis L. Albrecht Attorney, Agent, or FirmMonte D. Witte; Julius P. Filcik; Richard C. Witte 1 1 ABSTRACT Fluoride-containing laundry sours are rendered noncaking by the incorporation of anhydrous calcium sulfate or certain other anti-caking materials.
2 Claims, No Drawings NON-CAKING LAUNDRY SOUR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to compositions of matter useful as laundry sour products.
1. Description of the Prior Art Numerous steps in the processing of textiles involve contacting the textiles with various chemical compounds such as bleaching, dyeing, and washing compounds. At the conclusion of each step it is necessary that alkaline residues be removed from the textile fabrics before the next processing step. So, too, in laundering operations it has been found desirable to remove the residual soaps or synthetic detergents remaining on the laundered fabrics. Residue removal in both circumstances is commonly accomplished by contacting the fabrics with an aqueous solution of a composition exhibiting an acid reaction. These compositions are hereinafter referred to as laundry sours. Over the years, numerous acid materials have been used in compounding laundry sours. Today, the most commonly used materials are sodium silicofluoride (Na Si F sodium bifluoride (sodium acid fluoride, NaF.I-IF), and mixtures of the two. A common mixture will contain 75% by weight sodium silicofluoride and 25% by weight sodium bifluoride. In addition to the fluoride salts, additives are sometimes used in sour compositions. Very common additives are optical bleaches which are referred to in the art as brighteners. A common brightener level is 0.1% of the total fluoride salt content.
While the above-described fluoride salt mixtures adequately perform the desired souring function, commercial experience has demonstrated that the mixtures exhibit undesirable caking properties. That is, when the mixtures are stored in drums under unfavorable conditions of temperature and humidity, such as are frequently encountered in textile processing plants and commercial laundries, they exhibit a tendency to form hard lumps, cakes, and chunks. This caking tendency, while not interfering with the souring action once the product has been added to the souring bath, causes inconvenience to the operators of the textile plants and the commercial laundries in that the employees of these establishments must spend time breaking up the cakes and lumps in order to remove the laundry sour from its container and in order to dissolve the composition in the souring bath. There has long been felt a need in the textile processing and commercial laundry industries for a lau ndry sour com position which will be available at the time of its use in the'forrn of a free flowing powder. Certain additives, such as magnesium oxide, have been proposed for reducing the caking tendency of laundry sours, but deficiencies in terms of performance and cost have rendered them less than completely satisfactory.
SUMMARY OF THE INVENTION This invention relates to the addition of anhydrous calcium sulfate, and other anti-caking compounds, to laundry sours compounded of fluoride salts. It is an object of this invention to provide a fluoride-containing laundry sour which remains free flowing even after storage for extended periods in drums under adverse conditions of temperature and humidity.
DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been discovered that blending anhydrous calcium sulfate with a fluoride salt-containing laundry sour will render the sour composition free flowing even after storage under adverse conditions of temperature and humidity. This result is accomplished by adding to the laundry sour composition anhydrous calcium sulfate at from 0.1 to 1.5% by weight of the total fluoride salt present, preferably 0.3 1.0%.
The fluoride salt-containing laundry sour contemplated for use in this invention is composed of one or more of the common water-soluble fluoride salts used in laundry sours. Examples of such fluoride salts are sodium silicofluoride, zinc silicofluoride, ammonium silicofluoride, sodium bifluoride, and ammonium bifluoride. A preferred laundry sour composition is composed of sodium silicofl uoride and sodium bifluoride in a weight ratio of sodium silicofluoride to sodium bifluoride of 1:1 to 5:1. A highly preferred laundry sour is composed of sodium silicofluoride and sodium bifluoride in a weight ratio of 3:1.
While anhydrous calcium sulfate has been found to be the most highly preferred anti-caking material for addition to fluoride salt-containing laundry sours, other chemicals have been shown to be effective anti-caking agents. These other materials are anhydrous calcium chloride, anhydrous magnesium sulfate, anhydrous sodium dibasic phosphate and calcium tribasic phosphate. Each of these materials is used at levels of from 0.1 to 1.5% by weight of the total fluoride salt component of the laundry sour composition, preferably at levels of from 0.3 to 1.0% by weight of the total fluoride salt component.
Brighteners, such as disodium 4,4'-bis(4-morpholino-G-anilino-s-triazine-Z-yl-amino)-2,2-stilbene disulfonate, may option ally be used in the laundry sour at from 0.01 to 0.5% by weight of the total fluoride salts present. The preferred level of brightener is 0.1% by weight of the total fluoride salt present.
To make the non-caking laundry sours of this invention, the dry, powdered ingredients are intimately blended by hand or in a mechanical mixer such as a V- cone mixer or an internally baffled rotating drum mixer. In a preferred method of making a preferred non-caking laundry sour (i.e. one containing sodium silicofluoride and sodium bifluoride in a weight ratio of 1:1 to 5:1 the appropriate amount of anti-caking material is intimately blended with the sodium bifluoride component and this mixture is then intimately blended with the sodium silicofluoride component and the optional brightener, if one is used.
The following examples illustrate the use of this invention, but are not to be construed as in any way limiting the scope of the invention.
EXAMPLE I One-half (0.5) pound sodium bifluoride and 0.01 pound powdered anhydrous calcium sulfate were placed in an internally bafi'led rotating drum mixing apparatus. The apparatus was started and allowed to run for 2 minutes until an intimate mixture of the bifluoride and the calcium sulfate was obtained. The mixer was stopped and 1% pounds sodium silicofluoride and 0.002 pound brightener were added. The apparatus was started and allowed to run 6 minutes until an intimate mixture of the ingredients was obtained. The re- 3 sulting product was free-flowing even after storage at 90F. and 80% relative humidity for 5 days and it adequately performed its assigned souring task.
EXAMPLE [1 The procedure of Example I is repeated except that in successive batches of souring composition, the calcium sulfate is replaced in turn by 0.01 pound of anhydrous calcium chloride, 0.01 pound anhydrous magnesium sulfate, 0.01 pound anhydrous sodium dibasic phosphate, and 0.01 pound calcium tribasic phosphate. in each case, a non-caking laundry sour composition is obtained.
EXAMPLE [[1 An anti-caking souring composition is prepared as in Example 1 except that 0.03 pound anhydrous calcium sulfate is mixed with the sodium bifluoride. As in Example the mixture exhibits a lack of caking on storage under adverse conditions of temperature and humidity and successfully and adequately performs the desired souring task.
EXAMPLE 1V tion is blended until a uniform, intimate mixture is obtained. This souring composition demonstrates excellent anti-caking properties and adequately performs its souring function.
Laundry sour compositions prepared according to this invention can contain from about 98.52 to about 99.90% by weight of a water-soluble fluoride salt selected from the group consisting of sodium silicofluoride, sodium bifluoride and mixtures thereof, and from about 0.10 to about 1.48% by weight of an anti-caking agent selected from the group consisting of anhydrous calcium sulfate, anhydrous calcium chloride, anhydrous magnesium sulfate, anhydrous sodium dibasic phosphate and calcium tribasic phosphate. 1n a preferred embodiment, the laundry sour would contain from about 99.01 to about 99.70% by weight fluoride salt and from about 0.30 to about 0.99% by weight anticaking agent.
What is claimed is:
l. A non-caking laundry sour composition consisting essentially of:
a. sodium silicofluoride;
b. sodium bifluoride',
c. anhydrous calcium sulfate; wherein the weight ratio of sodium silicofluoride to sodium bifluoride is 3:1 and wherein the calcium sulfate is present at from 0.3 to 1% by weight of the total fluoride salt content.
2. The composition of claim 1 in which the anhydrous calcium sulfate is present at 0.5% by weight of the total fluoride salt content.