US2829104A - Nontarnishing detergent compositions containing vanadyl sulfate - Google Patents

Description

United S ates Patent NONTARNISHING DETERGENT COMPOSITIONS CONTAINING VANADYL SULFATE Edgar E. Ruff, Bergenfield, and Elwin E. Smith, Paramus, N. 1., assignors to Lever Brothers Company, New York, N. Y., a corporation of Maine No Drawing. Application June 28, 1956 Serial No. 594,353

11 Claims. (Cl. 252-135) This invention relates to detergent compositions containing a tarnish inhibitor and more particularly to polyphosphate compositions containing vanadyl sulfate as a tarnish inhibitor.

Compositions containing polyphosphates are now widely used for detergent and other purposes. Aqueous solutions of polyphosphates tend, when at'certain pH values, to tarnish German silver (a nickel-zinc-copper alloy) to a variety of shades from yellow to bluish-black, especially if the solutions are at elevated temperatures and are allowed to remain in contact with the alloy for several minutes. Since German silver is frequently used for household articles commonly washed in polyphosphatebuilt detergent compositions, it is evident that this is a serious problem.

In accordance with the instant invention polyphosphate compositions are provided containing a tarnish inhibitor which compositions inhibit the formation of tarnish upon German silver. The tarnish inhibitor of the invention is vanadyl sulfate.

An amount of the vanadyl sulfate is added to the poly:

phosphate composition which is sufficient to give tarnish inhibition when the composition is used in its normal way. It will be understood that the amount required will depend in part upon the tendency of the polyphosphate with which it is used to tarnish German silver and upon the amount of polyphosphate present. In general, therefore, at least about 2%, and preferably at least about 7%, of the vanadyl sulfate based on the weight of the polyphosphate present in the detergent composition will inhibit the formation of tarnish by the composition. The maximum amount of the vanadyl sulfate'is not critical, but more than is necessary to give the desired effect will usually not be used, and of coursean amount in excess of that soluble in an aqueous solution of the composition would not be used. In most cases, the maximum suggested would be about 15% based on the weight of the polyphosphate.

The tarnish inhibitor of the present invention is effective with water-soluble alkali metal polyphosphates at pH values where such polyphosphates tend to tarnish German silver. Thus, vanadyl surfate is effective over a pH range of about 7 to about 11.- The alkali metal polyphosphates may include, by way of example, pentasodium and pentapotassium tripolyphosphates, tetrasodium and tetrapotasslum pyrophosphates, sodium and potassium hexametaphosphates, and hexasodium and hexapotassium tetrapolyphosphates. polyphosphate which need be employed in the compositions, the amount of polyphosphate in the compositions being dictated only by the optional presence of organic nonsoap detergents and builders which might be included in thedetergent compositions. p

' Examples; of such additional optional components are organicnonsoap detergents which may be either anionic, cationica or nonionic detergents and builders, water, and

inert materials. These detergent compositions may contain alkali metal polyphosphatein any amount, usually between 5% and 50%; conventional proportions of non- There is no critical amount of alkali metal soap detergent, usually within the range between 5% and I 40%; from about 2%, and preferably from about 7%, to about 15% of vanadyl sulfate based on the weight of the polyphosphate; and the balance builders and inert materials.

The alkylaryl sulfonates are a class of anionic deterthe benzene ring, and having the following general.

structure CHzRi where M is hydrogen, an alkali metal or an organic amine cation, and R and R are alkyl, of the type formula C l-1 and at least one R is a polypropylene group, the whole alkyl group containing preferably twelve to fifteen carbon atoms. These are known compounds whose preparation and properties are set forth in U. S. Patent No. 2,477,383 to Lewis, issued July 26, 1949; they are available in commerce under the trade names Oron-' ite, Ultrawet, and Neolene.

Another class of useful nonsoap detergents are the amidoalkane sulfonates which are characterized by the following structure: I

where A is hydrogen or alkali metal, i. e., ammonium, sodium, or potassium, n is a small whole number from one to about five, preferably two or three, R is hydrogen or an alkyl, aryl, or cycloaliphatic group, such as methyl, and R. is an alkyl or alkylene radical, such as'r'nyristyl,

such as N-methyl taurine, or aminopropanesulfonic acid,

Other water-soluble alkyl aromatic sulfonic acids may constitute optional components such as those prepared by alkylating benzene or naphthalene with a kerosenefraction followed by sulfonation toaliphatic sulfonic acids, esters of sulfuric acid with aliphatic alcohols of ten to eighteen carbon atoms, particularly those derived by the' reduction of coconut oil, palm oil, and like long-chain fatty acids, sulfonated castor oil, esters and ethers of isethionic acid, long-chain fatty acid esters and long-chain alkyl ethers of 2,3'-dihydroxypropane sulfonic acid and sul-v furic acid esters of monoglycerides and glycerol mono ethers. The salts of these acids are ordinarily employed.

The tarnish inhibitors are also useful with nonionic detergents containing polyphosphates, such as, for example, alkyl oxyether and ester and thioether and ester detergents having the following general formula: a n

Patented Apr. 1, 1958 where R is a straight or branched chain saturated Or unsaturated hydrocarbon group having from eight to eighteen carbon atoms or an aralkyl' group having a straight or branched chain saturated or unsaturated hydrocarbon group of from eight to eighteen carbon atoms attached tothe aryl nucleus, and attached to A through the aryl nucleus, A is selected from the group consisting of ethereal oxygen and sulfur, carboxylic ester and thiocarboxylic ester groups and x is a number from eight to twenty. R can, for example, be a straight or branched chain octyl, nonyl, decyl, lauryl, myr istyl, cetyl, or stearyl group, or an alkylaryl group such as octylbenzene, nonylbenzene, decylbenzene, stearylbenzene, etc.

The sulfated ethoxynated derivatives of the above also are useful. anionic detergents:

where M is hydrogen or an alkali metal or organic amine cation and x, A and R are as above.

WhenR is alkyl it will be evident that the detergent can be regarded as derived from an alcohol, mercaptan, oxyor thio fatty acid of high molecular weight, by condensation with ethylene oxide. Typical of this type of alkyl ether are the condensation products of oleyl or dodecyl alcohol or mercaptan with from 8 to 17 moles of ethylene oxide, such as Emulfor ON," Nonic 218 and Sterox SE and SK. Typical alkyl esters are G1226 and Renex (polyoxyethylene ester of tall oil acids), "Sterox CD" and Neutronyx 330 and 331 (higher fatty acid esters of polyethylene glycol).

Where R is aralkyl, the detergent can be derived from an alkyl phenol or thiophenol.

The ethoxynated alkyl phenols and thiophenols have the following general formula:

where R is a straight or branched chain saturated or unsaturated hydrocarbon group having at least eight carbon atoms up to approximately eighteen carbon atoms, A is oxygen or sulfur and x is a number from eight to twenty. R can, for example, be a straight or branched chain octyl, nonyl, decyl, lauryl, cetyl, myristyl, or stearyl group. Typical are the condensation products of octyl and nonyl phenol and thiophenol with from 8 to 17 moles of ethylene oxide, available commercially under the trade names NIW, Antarox A-400, Igepal CA and CO, Triton X400, Neutronyx 600 and Tergitol NFX.

The optional supplemental builders may be alkali metal inorganic salts, typical examples of which include sodium and potassium sulfates, sodium and potassium chlorides, sodium and potassium silicates, and sodium and potassium carbonates.

In addition to or instead of the above mentioned supplemental inorganic salts, organic materials, such as sodium carboxymethylcellulose may be used as builders.

The builder mixture is so chosen among alkaline, neutral and acidic salts that the composition obtained in an aqueous 0.14% washing solution has a pH of about 7 or above. Preferably its pH lies in the range of about 7 to about 11, since solutions which are more alkaline may be irritating to the skin and tend to weaken some fabrics, particularly woolens.

The detergent compositions of the'invention inhibit theformation of tarnish upon German silver in either hard or soft water. It will be appreciated that the detergent compositions may exist in any dry form, such as drum-dried or spray-dried detergent compositions, or may be in liquid form.

The polyphosphate detergent compositions may be pre pared by conventional methods, as by blending the ingredients thereof in an aqueous solution or slurry and then drying the resulting mixture in a spray or drum dryer at elevated temperatures.

The tarnish inhibitor may be added to the polyphosphate composition in any stage of its manufacture, to the finished polyphosphate composition, or to the polyphosphate solution.

The compositions of the invention will be further illustrated by the following examples wherein vanadyl sulfate was employed in the compositions 35.8. tarnish inhibitor. The vanadyl sulfate was tested as a solution prepared by dissolving 5.0 grams of blue crystal vanadyl sulfate in one liter of water.

In these examples the following test procedure was employed. Five grams of a polyphosphate composition (or an equivalent weight of a component thereof where specified) were dissolved in 600 milliliters of water. Onetenth, of this volume, or 60 milliliters, was placed in a 200 milliliter beaker, and the required volume of inhibitor solution added. The volume of solution in the beaker was made up to milliliters. The final concentration of polyphosphate composition or component is equivalent to five grams whole composition per quart of water. The pH at room temperature was adjusted to the desired level with sodium hydroxide or hydrochloric acid solutions. The solution was then heated to -165 F., and placed in a water bath to maintain the temperature of the solution at 160-l65 F. A German silver metal strip, one inch by six inches, cleaned with a Noxon metal polish. rinsed, and buflfed with a cloth, was partially immersed in the solution and allowed to remain for one/half hour. At the end of that time, the strip was removed, rinsed, dried with a cloth, and visually examined for tarnish. The etfectiveness of the tarnish inhibitor was rated as follows:

Grade No. Degree of Taruish No tarnish.

Interface stain only.

Barely noticeable tarnish.

Slight tarnish.

s Moderate tarnish.

Considerable (heavy) tarnish. Severe, as when inhibitor is absent.

Examples 1-2 below show that vanadyl sulfate inhibits the formation of tarnish by tetrasodium pyrophosphate.

EXAMPLES 1-2 Percent Vanadyl Sulfate (polyphosphate basis)... Tarnish Grade The addition of vanadyl sulfate to polyphosphate compositions containing an organic nonsoap detergent, which may be either anionic, nonionic, or cationic, as well as builders inhibits the formation of tarnish by such detergent compositions. This is clearly illustrated by the examples set forth below wherein the six compositions of Table I were employed.

I. Table III ompos1tions. 0

Sodium Dodecylbenzene Sult'onate.- Laurie Ester of N-(beta-hydroxyethyl) alpha (chloropyridluium) aoetamide [Emulsept] Plnronic L-64 Pentasodium Tripolyphosphate- Tetrasodium Pyrophosphate Sodium Hexametaphosphate...

Hexasodium Tetrap'olyphosphate Sodium Silicate 7 Sodium Carbonate gadlnm Carboxymethylcellulo ater Sodium Sulfate Total 100. 100.

I In Compositions A through F the amounts of the various components are expressed in percent by weight. PluronicL-64 is an organic nonionic nonsoap detergent having the empirical formula H zHr itt am )n iHi u To five grams each of Compositions A and B there was added vanadyl sulfate in the proportions shown below and the testprocedure carried out with the following results. In Examples 3-6 the pH of the test solution was 9, while in Examples 7-10 the pH of the test solution was 7.

Percent vanadyl Sulfate (polyphosphate S18 0.0 212 4. 4 6. 7 Grading (Composition A) (Examples 36). 6 3 1 3 Grading (Composition 13) (Examples 7-10)... 6 4 4 3 Vanadyl sulfate is effective as a tarnish inhibitor in polyphosphate compositions containing an organic nonsoap detergent as well as supplemental builders when the alkali metal polyphosphateis other than tetrasodium pyrophosphate or pentasodium tripolyphosphate, for example, sodium hexametaphosphate or hexasodium tetrapolyphosphate. This is clearly illustrated by Examples 11-14 set forth below.

EXAMPLES 1i-14 Five grams each of Compositions E and F per quart of distilled water tested in accordance with the test procedure at pH 8 both tarnished German silver to a grading of 6, i. e., severe tarnish. When 6.7% of vanadyl sulfate based on the weight of polyphosphate was added to Compositions E and F, the tarnish grading of both compositions upon German silver at pH 8 was reduced to grade 1, indicating interface stain only.

Vanadyl sulfate is also effective as a tarnish inhibitor in polyphosphate compositions containing either an or ganic cationic nonsoap detergent or an organic nonionic nonsoap detergent as well as supplemental builders, as illustrated by Examples 15-18.

EXAMPLES 15-18 Five grams each of Compositions C (cationic detergent) and D (nonionic detergent) per quart of distilled vanadyl sulfate based on the weight of polyphosphate was added to each of these compositions, the two compositions so produced then had a tarnish grading at pH 8 of 3, indicating slight tarnish.

The amount of alkali metal polyphosphate presentin the polyphosphate composition may be as low as about 5% as noted above and as further illustrated by Examples 19-20.

EXAMPLES 19-20 5% of tetrasodium pyrophosphate was employed in Composition A with the amount of sodium sulfate being increased to offset the decrease in the tetrasodium pyrophosphate content of the composition (40% additional sodium sulfate). Five grams of this modified composition per quart of distilled water at pH 10 had a tarnish grading of 4 upon German silver metal, whereas fi've grams of the modified composition per quart of distilled water which also contained 6.7% of vanadyl sulfatebased on the weight of polyphosphate at pH 10 had a reduced tarnish grading of 1.

Vanadyl sulfate is effective as a tarnish inhibitor when incorporated in a detergent-polyphosphate slurry and the slurry drum-dried as shown by Example 21.

EXAMPLE 21 The composition shown below was prepared in the form of an aqueous slurry having 30% water content and drum-dried. Five grams of the drum-dried product per quart of distilled water tarnished German silver only to grade 3 at its natural pH of 10.35;

1 Percent vanadyl sulfate, based on polyphosphate, 6.7.

Examples 22-23 illustrate the fact that vanadyl sulfate is effective as a tarnish inhibitor in polyphosphate compositions when the polyphosphate compositions are used in hard water. It will be noted that in all of the previous examples the water was soft water, i. e., distilled water.

EXAMPLES 22-23 Five grams of Composition B per quart of water having a hardness of p. p. m. at pH 7 tarnished German silverto grade 6, whereas five grams of Composition B containing 6.7 ofvanadyl sulfate based on the weight of polyphosphate per quart of water having a hardness water tested in accordance with the test procedure at pH 8 tarnished German silver to grade 6. When 6.7% of of 180 p. p. m. at pH 7 tarnished German silver only to grade 3. V

The effectiveness of vanadyl sulfate as a tarnish inhibiclearly illustrated in Examples 24-25.

EXAMPLES 24-25 Two 11.25 gram portions of the following liquid detergent composition were dissolved separately in one quart tion at the concentration indicated below.

grading of a strip of German silver metal insertedjin each of the solutions at pH 11 is also set forth. It will be noted that 11.25 grams of the liquid product provides the same amount of polyphosphate (2.25 grams) as the standard five grams of granulated detergent containing 45% poly-' phosphate.

Composition Percent by Potassium Dodeeylbenzcne Su1f0nate. 10.0 Sodimn Xylene Sultanate... 7. 6 Llurie Isopropanolamide. 3. 2 Laurie Diethanolamide 3. 8 Tetrapotassium Pyiophosphate 20.0 Sodium Silica 7. Water 48.4

Total 100.0

Example N o 24 25 Percent Vanadyl Sulfate (polyphosphate basis) 0.0 2. 2 Tarnish Grade 6 3 It should be borne in mind that this invention relates to tarnishing and tarnish inhibitors and does not pertain to alkaline corrosion and corrosion inhibitors. Tarnishing and corrosion of metals are two quite dissimilar phenomena. A discoloration is the principal manifestation of tarnishing, while a dissolving action characterizes corrosion of metal. Corrosion inhibitors are effective because they remove oxygen from the alkaline medium surrounding the metal being corroded. The antitarnishing action of vanadyl sulfate on German silver, on the other hand, is due to a different mechanism, since the presence of oxygen is not necessary to the tarnishing action of polyphosphates on German silver.

.Obviously many modifications and variations may be made in the invention herein set forth without departing from the spirit thereof, and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A detergent composition consisting essentially of an alkali metal pyrophosphate which in aqueous solution tarnishes German silver and vanadyl sulfate in an amount to lessen the tarnishing action of the pyrophosphate.

2. A detergent eom position consisting essentially of an alkali metal pyrophosphate which in aqueous solution tarnishes German silver and from about 7% to about 15% of vanadyl sulfate based on the weight of the polyphosphate to lessen the tarnishing action of the pyrophosphate.

3. A detergent composition consisting essentially of from about 5% to about 50% of an alkali metal polyphosphate which in aqueous solution tarnishes German silver, from about 5% to about 40% of an organic nonsoap detergent, and vanadyl sulfate in an amount from about 2% to about 15% based on the weight of polyphosphate and sufficient to inhibit such tarnishing.

4. A detergent composition consisting essentially of from about 5% to about of an alkali metal polyphosphate which in aqueous solution tarnishes German silver, from about 5% to about 40% of an organic nonsoap detergent, and vanadyl sulfate in an amount from about 7% to about 15% based on the weight of the polyphosphate and sufiicient to inhibit such tarnishing.

5. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal tripolyphosphate.

6. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal pyrophosphate.

7. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal hexamctaphosphate.

8. A detergent composition as set forth in claim 4 wherein the polyphosphate is an alkali metal tetrapolyphosphate.

9. A detergent composition as set forth in claim 4 wherein the organic nonsoap detergent is an organic cationic nonsoap detergent.

10. A detergent composition as set forth in claim 4 wherein theorganic nonsoap detergent is an organic nonionic nonsoap detergent.

11'. A detergent composition as set forth in claim 4 wherein the organic nonsoap detergent is an organic anionic nonsoap detergent.

References Cited in the file of this patent UNITED STATES PATENTS 2,303,399 Schwartz Dec. 1, 1942 2,419,805 Wegst Apr. 29, 1947 2,425,907 Wegst Aug. 19, 1947 2,618,604 Schatfer Nov. 18, 1952 OTHER REFERENCES Smiths College Chemistry, William F. Ehret, 6th edition, 1946, Periodic Classification of the Elements on inside back cover.

Claims (1)

1. A DETERGENT COMPOSITION CONSISTING ESSENTIALLY OF AN ALKALI METAL PYROPHOSPHATE WHICH IN AQUEOUS SOLUTION TARNISHES GERMAN SILVER AND VANADYL SULFATE IN AN AMOUNT TO LESSEN THE TRANISHING ACTION OF THE PYROPHOSPHATE.