US2829106A - Nontarnishing detergent compositions containing a water-soluble inorganic tantalate - Google Patents

Description

N ONTARNISHING DETERGENT COMPOSITIONS CONTAINING A WATER-SOLUBLE INOR- GANIC TANTALATE Edgar E. Rulf, Bergenfield, and Elwin E. Smith, Paramus, N. J., assignors to Lever Brothers Company, New York, N. Y., a corporation of Maine No Drawing. Application June 28, 1956 Serial No. 594,355

12 Claims. (Cl. 252135) This invention relates to detergent compositions containing tarnish inhibitors and more particularly to polyphosphate compositions containing water-soluble inorganic tantalates as tarnish inhibitors.

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 forhousehold articles commonly washed in polyphosphate-built 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 inhibitors of the invention are water-soluble inorganic tantalates, for example, so-' dium tantalate and potassium tantalate.

An amount of the water-soluble inorganic tantalate is added to the polyphosphate composition which is suflici'ent 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 tarnish inhibiting properties of the particular tantalate in question, upon the tendency of the polyphosphate with which it is used to tarnish German silver, and upon the amount of the polyphosphate present. In general, therefore, at least about 4% of the water-soluble inorganic tantalate based on the weightof the polyphosphate present in the detergent composition will inhibit the'formation of tarnish by the composition. The'maximum amount of the tantalate is not critical, but more than is necessary to give, the desired effect will usually not be used, andof course an 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 polyphosphate.

The tarnish inhibitors of the present invention are effective with water-soluble alkali metal polyphosphates with-- in the range of about pH 10 to about pH 11. The alkali metal polyphosphates may include, by way of example, pentasodium and pentapotassium tripolyphosphates, tetrasodium and tetrapotassium pyrophosphates, sodium and potassium hexamethaphosphates, and hexasodium and hexapotassium tetrapolyphosphates. 'There is no critical amount of alkali metal 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 includecl'in the detergent compositions.

Examples of such additional optional components are organic nonsoap detergents which may be either anionic, cationic, or nonionic detergents and builders, water, and inert materials. These detergent compositions may contain alkali metal polyphosphate in any amount, usually ice Patented Apr. 1, 1958 between 5% and 50%; conventional proportions of nonsoap detergent, usually within the range between 5% and 40%; from about 4% to about 15% of a water-soluble inorganic tantalate based on the weight of the polyphosphate; and the balance builders and inert materials.

The alkylaryl sulfonates are a class of anionic detergents which may be included in the detergent compositions. One example thereof is the sulfonated phenyl polypropylene alkanes', characterized by the branched chain structure of polypropylene and a tertiary alkyl carbon at the henzene ring, and having the following general structure:

. CHaRz SOsM where A is hydrogen or alkali metal, i. e., ammonium, sodium, or potassium, n is a small whole number fromone to about five, preferably two or three, R ishydrogen, or

an alkyl, aryl, or cycloaliphatic group, such as methyl, and R, is an alkyl oralkylene radical, such. as myristyl, palmityl oleyl, and stearyl. Sodium palmitic tauride, sodiumpalmitic methyl tauride, sodium myristic methyl tauride, sodiumpalmitic-stearic methyl tauride, and sodium palmitic methyl amidopropane sulfonate are typical examples thereof.

These compounds are prepared by interacting the corresponding aliphatic acid anhydride or halide with an organic aliphatic aminosulfonic acid, such as taurine,

NH CH CH SO H, and the various N-substituted taurines,

such as N-methyl taurine, or aminopropane sulfonic acid, Hz( 2)a a Other water-soluble alkyl aromatic sulfonic acids may constitute optional components such as those prepared by alkylating benzeneor naphthalene with a kerosene fraction followed by sulfonationto aliphatic sulfonic acids, esters of sulfuric acid withaliphatic 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 sulfuric acid esters of monoglycerides and glycerol monoet'hers. The salts of these acids are ordinarily employed.

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

where R isa straight or branched chain saturated orrune saturated hydrocarbon group having 4 from eight to eighteencarbon. atoms... or. an. aralkyl group. having. a.

straight or branched chain saturated or unsaturated hydrocarbon group of from eight toeightecn carbon atoms attached 'to the aryl. nucleus, and attached itoqi At; through. the :aryl nucleus, .A .is selected from thehgroup, consisting. of ethereal oxygen and sulfur, .carboxylic: .ester and thiocarboxylic .ester groups andqx is anumber. fromzeightto.

twenty. R can, for example, bea straight or. branched:

chain octyl, nonyl, decyl, lauryl,.myristyl,.cetylror stearyl group, or an alkylaryl group such asoctylbenzene, nonylbenzene, decylbenzene, stearylbenzene, etc.

The sulfated ethoxynated derivatives of the abovealso are useful anionic detergents:

Renex" (polyoxyethyleneester of talloil 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 branchedchain 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 NIWZ Antarox A-400, Igepal CA and CO, Triton X,100, Neutronyx 600. and Tergitol NFXJ 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 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. 10 or 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 the formation 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 drumdried or spray-dried detergent compositions, or may be in liquid form.

Thespolyphosphate detergent compositions may be: prepared' by conventional methods, as by blending the ingredients. thereotin an aqueous. solutionor u y nd. 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 polyphosphatc composition, or to the polyphosphate solution.

The compositions of'the. invention will be furtherillustrated by the following examples wherein a typical watersoluble inorganic tantalate, namely potassium tantalate, was employed in theeompositions. The potassium tantalate was tested as a solution of potassium tantalateprepared by fusing 0.25 gram of tantalum pentoxide with 2.0 grams ofpotassium carbonate, cooling the melt, and dissolving the resulting potassium tantalate in 500 milliliters of water.

In these examplesthefollowingtest procedure was employed. Five grams of a polyphosphate composition (or an .equivalent weight ofa componentthereof wherelspecified).werc dissolved in 600 milliliters of'water. Onetenthzof 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 wasmade 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 buffed 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 efiectiveness of thetarnish inhibitor was rated as follows:

No tarnish.

Interface stain only.

Barely noticeable tarnish.

Slight tarnish.

Moderate tarnish.

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

Examples l-Zbelow show that a water-soluble inorganic tantalate inhibitsthe formation of tarnish by a tripolyphosphate, such as pentasodium tripolyphosphate.

EXAMPLES l-2 Two separate; portions of pentasodium tripolyphosphate were dissolved in distilled water and to one there was added 6.7% of potassium tantalate (expressed as tanta lum .pentoxide) andthe volumes diluted in accordance withthe: above. test procedure. Th pH of both solutions was; 11. Each, solution had a concentration of 2.25 grams. of. polyphosphate per: quart; of distilled water.

The. test. solution without; thepotassium tantalate.

or cationic, asrwell; as=supplemental builders inhibits the formation oftarnish, by such detergent compositions, This is. clearlyillustrated by the examples set forth be low wherein the: seven compositions of Table I were employed.

Table l Compositions A B D E G Sodium Dodeeylbenzene Sulfonate.; 18.0 18.0 18.0 18.0 Laurie Ester of N-(beta-hydroxy-ethyl)-alpha- V V (chloropyridinium) acetamide [Emulsep l 18.0 18. 0 Pluronie L454 18.0 Pentasodium Tripolyphosphate 45. 0 45. 0 45. 0 Tetrasodium Pyropbnsnhatn 45. 0 45. 0 Sodium Hexametaphosphare 45. 0 Hexasodlum Tetrapolyphosphata; 45. 0 Sodium Sillcate 6. 0- 6.0 6.0 6.0 6.0 6. 0 6. 0 Sodium Carbonate 3. 0 3.0 3.0 3.0 3. 0 3.0 3.0 Sodium Garboxymethylcellulo 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Water 10. 0 10.0 7.0 7.0 7.0 7.0 7. 0 Sodium Sulfate; 17. 17. 5 20. 5 20. 5 20. 5 20. 5 '20. 5

Total k 100. 0 100. 0 100. 0 100. 0 100. 0 100. 0 100. 0

In Compositions A through G the amounts of the var- EXAMPLES 14-19 ious components are expressed in percent by weight. Pluronic ll-.64 is an organic (nonionic nonsoap detergent having the empirical formula prepared by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol where b. is an integer selected from the group consisting of 26 to 30 and a plus 0 is an integer-such that the molecule contains from 40% to 50% of ethylene oxide.

Examples 3-9 show that at least about 4% of a watersoluble inorganic tantalate basedon the weight of polyphosphate inhibits the formation of tarnish by polyphosphate compositions containing an organic anionic nonsoap detergent and supplemental builders.

EXAMPLES 3-9 To five grams each of Compositions A and B there was added potassium tantalate in the proportions shown below and the test procedure carried out with the following results. In Examples3-5 the pH of the test solution was 11, while in Examples 6-9 the pH of the test solution was 10.

Percent Potassium Tantalate (expressed'as Tantalum Pentoxide) polyphosphate basis. 0. 0 3. 3 p 4. 4 6. 7 Grading (Composition A) (Examples 3-5)..." 6' 3 p 3 Grading (Composition B) (Examples (5-9)-... 6 3 3 3 A water-soluble inorganic tantalate is effective as a tarnish inhibitor in polyphosphate compositions containing an organic nonsoap detergent as well as supplemental builders when the. alkali metal polyphosphate is other than tetrasodium pyrophosphate or pentasodium tripolyphosphate, for example, sodium hexametaphosphate or hexa-' sodium tetrapolyphosphate. This is clearly illustrated by Examples 10-13 set forth below.

EXAMPLES 10-13 Five grams each of Compositions F at pH 10 and G at pH 11 per quart of distilled water tested in accordance with the test procedure both tarnished German silver to a grading of 6, i. e., severe tarnish. When 6.7% of potassium tantalate (expressed as tantalum pentoxide) based on the weight of polyphosphate was added to Composition F, the tarnish grading of the composition upon Five grams each of Compositions C and D (cationic detergents) and E (nonionic detergent) per quart of dis tilled water were tested in accordance with the test procedure. Composition C having apH of 10 and Compositions D and E having a pH of 11 all tarnished German silver to grade 6. When 6.7% of potassium tantalate (expressed as tantalum pentoxide) based on the weight of polyphosphate was added to each of these compositions, the three compositions so produced then had a reduced tarnish grading at the specified pH values of 4 for Composition C and 1 for Compositions D and E.

The amount of the alkali metal polyphosphate present in the polyphosphate compositions may be as low as about 5% as noted above and as further illustrated by Ex- EXAMPLES 20-21 5% of pentasodium tripolyphosphate was employed in Composition B with the amount of sodium sulfate being increased to olfset the decrease in the pentasodium tripolyphosphate 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 five grams of the modified composition per quart of distilled water which also contained 6.7% of potassium tantalate (expressed as tantalum pentoxide) based on the weight of polyphosphate at pH 10 had a reduced tarnish grading of 2.

Examples 22-23 illustrate the fact that the watersoluble inorganic tantalates are effective as tarnish inhibitors in polyphosphate compositions when the poly-- phosphate 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 11 tarnished German silver to grade 5, whereas five grams of Composition B containing 6.7% of potassium tantalate (expressed as tantalum pentoxide) based on the weight of polyphosphate per quart of water having a hardness of 180 p. p. m. at pH 11 tarnished German silver only to grade 1.

The effectiveness of water-soluble inorganic tantalates as tarnish inhibitors with liquid polyphosphate detergent compositions is clearly illustrated in Examples 24-26.

EXAMPLES 24-7-26 Three five gram portions of the following liquid detergent composition were dissolved separately in one quart of distilled water and potassium tantalate added thereto at the concentrations indicated below. The tarnish grading of a strip of German silver metal inserted in each of the solutions at pH 10 is also set forth.

Composition Percent by Weight Potassium Dodecylbenzene Sultonate 10. Sodium Xylene Sulfonate 0.. 7.6 Laurie Isopropanolamide.--- 3.2 Laurie Dlethanolamlde 3. 8 Tetrapotmslum Pyrophosphate I 20. 0 Sodium Slllmtp 7, 0 Water---- 48. 4

Total 100.0

Example No-.-.' t 24 25 26 Percent Potassium Tantalata (expressed as Tantalum Pentoxide), polyphosphate basis O. 0 7. 16.0 Tarnish Grade 6 3 3 It should be borne in mind that this invention relates to tarnishing and tarnish inhibitors and does not pertain 'to alkaline corrosion or 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 eaecnve because they remove oxygen fromthe alkaline medium surrounding the metal being corroded. The anti'tarin'shing action of a water-soluble inorganic tantalate on German silver, on the other hand, is due to a different mechanism, since the presence of oxygen is not necessary tofthe 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 and, scope thereof, and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A detergent composition consistingessentially of an alkali metal tripolyphosphate which in aqueous solution -tarnishes German silver and a water-soluble inorganic tantalate in an amount to lessen the tarnishing action of the polyphosphate.

2. A detergent compositionconsisting essentially of an alkali metal tripolyphosphate which in aqueous-solution tarnishes, German silver and from about 4% to about 15% of a water-solubleinorganic tantalate based on the 4 weight of polyphosphate to lessen the tarnishing action of the polyphosphate.

-soap detergent, and a water-soluble inorganic tantalate in an amount from about 4% to about 15% based on Y the weight of polyphosphate and sufficient 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 hexametaphosphate.

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

9. A detergent composition as set ,forth in claim 4 wherein the water-solubleinorganic tantalate is potassium tantalate.

10. A detergentcompoSitioh .as set forth in claim 4 wherein the organic n'onsoap detergent is an organic cationic nonsoap detergent;

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

12. A detergent composition as set forth'in claim 4 wherein the organiononsoap .1 detergent is an organic anionic nonsoap detergent.

References Cited in the fileof this patent UNITED STATES PATENTS 2,303,399 Schwartz a... Dec. 1, 1942 2,419,805 Wegst Apr. 29, 1947 2,425,907 Wegst Aug. 19, 1947 2,618,604 Schaetfer 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 TRIPOLYPHOSPHATE WHICH IN AQUEOUS SOLUTION TARNISHES GERMAN SILVER AND A WATER-SOLUBLE INORGANIC TANTALATE IN AN AMOUNT TO LESSEN THE TARNISHING ACTION OF THE POLYPHOSPHATE.