US3640878A - Alkaline detergent composition - Google Patents

Abstract

A DISHWASHING DETERGENT COMPOSITION CONTAINING SODIUM SILICATE, PENTASODIUM TRIPOLYPHOSPHATE AND SODIUM FLUOSILICATE. THE LATTER ACTS TO PROTECT THE OVERGLAZE PATTERNS OF FINE CHINA. OTHER ALKALI METAL SILICATES, PHOSPHATES, CARBONATES, FLUOSILICATES AND CHELATES MAY BE USED. AN ANTISPOTTING AGENT, ACTIVE OXYGEN, OR CHLORINE BLEACHING AGENT (YIELDING HYPOCHLORITE CHLORINE) AND AN ORGANIC DETERGENT MAY ALSO BE PRESENT.

Description

United States Patent 3,640,878 ALKALINE DETERGENT COMPOSITION William Chirash, New Providence, and Richard Lerda Burke, Madison, N.J., assignors to Colgate-Palmolive Company, New York, N .Y. e No Drawing. Filed May 29, 1969, Ser. No. 829,115 Int. Cl. C11d 7/56 US. Cl. 252-99 8 Claims ABSTRACT OF THE DISCLOSURE A dishwashing detergent composition containing sodium silicate, pentasodium tripolyphosphate and sodium fluosilicate. The latter acts to protect the overglaze patterns of fine china. Other alkali metal silicates, phosphates, carbonates, fluosilicates and chelates may be used. An antispotting agent, active oxygen, or chlorine bleaching agent (yielding hypochlorite chlorine) and an organic detergent may also be present.

This invention relates to alkaline detergent compositions.

In accordance with one preferred aspect of this invention, a water soluble alkaline detergent composition for automatic dishwashing comprises a solid water soluble sodium silicate having an SiO :Na O mol ratio of about 1:1, 2. solid water soluble sodium phosphate wherein the P O :Na O mol ratio is about 0.711 to 3:1 and a metal fluosilicate.

The inclusion of the fluosilicate in the dishwashing compositions of this invention greatly decreases the adverse effect of the automatic dishwashing process on the designs and patterns of fine china, while yielding dishwashing compositions having excellent characteristics of stability, flow (even after extended exposure to elevated storage temperatures), avoidance of filming or water spotting, and non-corrosiveness to aluminum and other characteristics desirable for automatic dishwashing compositions.

As the metal fluosilicate, it is preferred to use sodium fluosilicate. Other alkali metal fluosilicates such as those of potassium or lithium may also be used, as may other metal fluosilicates that are hydrolyzed in a hot basic solution of pH above 7. Examples of other fluosilicates are aluminum, zinc, beryllium and others which do not interfere with the washing process or reduce the effectiveness of the selected ingredients at the use pH by forming undesirable precipitates or soluble complexes. While we do not wish to be bound to any theory explaining the beneficial effects of the presence of the fluosilicate, we are of the opinion that the fluosilicate hydrolyzes to form silicate and to lower the pH of the solution, and that these two phenomena help to account for the protection afforded to the overglaze patterns of fine china by the presence of the fluosilicate. The phosphate is preferably a condensed phosphate and, most preferably, a tripolyphosphate. It is also within the scope of the invention to use pyrophosphates, hexametaphosphates or orthophosphates, or mixtures thereof in place of all or part of the tripolyphosphate. Sodium phosphates are preferred but potassium may replace all or part of the sodium. The phospate generally constitutes about 0 to 70% of the final composition, preferably about 40 to 70%.

The sodium silicate used in the compositions of the invent-ion is preferably solid granular sodium metasilicate, a commercially available material. It is in conjunction with this material that the fluosilicate shows its greatest utility. In the broader aspects of the invention, however, sodium silicates, in which, the mol ratios of SiO :Na O are more than 1:1 e.g. 2:1 or 3.2: 1, may be used in place of the sodium metasilicate. In that case an aqueous liquid 3,640,878 Patented Feb. 8, 1972 sodium silicate of high SiO content (e.g. having an SiO :Na O mol ratio of 2.1:1 or 2.9:1) may be blended with solid particles of an anhydrous alkaline condensed phosphate (such as pentasodium tripolyphosphate) so as to hydrate the phosphate, with evolution of heat, while stirring and maintaining the temperature low enough so that the mixture is maintained as discrete particles rather than as a paste. The sodium silicate generally constitutes about 10 to 30% of the final composition and preferably about to In the broader aspects of the invention the fluosilicate may be used as the total source of silicate usually in combination with a highly alkaline ingredient such as carbonates or orthophosphates. In these cases the fluosilicate will constitute 10 to 40% of the final composition and preferably about 25 to It is preferred to use an amount of fluosilicate such that the pH of an aqueous solution of the composition, containing 0.15% of the total composition (the pH being measured at a temperature of 25 C. immediately after the solution is made) is reduced by at least 0.2 unit by the presence of the fluosilicate, preferably to a pH of about 10 (e.g. in the range of 9.5-10.5). For example, in the absence of the fluosilicate, a composition containing 66.9 parts of pentasodiurn tripolyphosphate hexahydrate, 20 parts of sodium metasilicate, 1.2 parts of sodium sulfate and 1.5 parts of organic detergent and 1.6 parts of a chlorine-yielding bleach showed a measured pH of 11.4. The addition of about 8% of sodium fluosilicate lowered the pH to about 10. Generally above about 2%, preferably over about 7% of the fluosilicate will be employed. The amount of this ingredient will usually be less than about 20%, preferably less than about 15% and most preferably less than about 12% except as hereinbefore stated. The pH of the composition is preferably at least 9.5. The pH can be as low as 8.5 where SiO may precipitate but usually is extremely soft and is fairly innocuous from a washing standpoint. Below pH 8.5 the SiO precipitate may leave undesirable deposits.

Additional optional, but desirable, constituents include a chlorinating agent or anti-spotting agent and a lowfoaming organic wetting agent or detergent.

As a suitable anti-spotting agent, it is preferred to use a dry, water-soluble compound which, on contact with water, liberates hypochlorite chlorine, i.e., those watersoluble dry solid materials which generate hypochlorite ions on contact with, or dissolution in water. Examples thereof are the dry, particulate heterocyclic N chlor imides such as trichlorocyanuric acid, dichlorocyanuric acid, and salts of dichlorocyanuric acid such as sodium dichlorocyanurate and potassium dichlorocyanurate. Other imides may also be used such as N-chlorosuccinimide, N-chloromalonimide, N-chlorophthalimide and N-chloronaphthalimide. Additional suitable imides are the hydantoins such as 1,3-dichloro-5,5-dimethylhydan toin; N-monochloro C,C dimethylhydantoin; methylene-bis (N-chlor-C,C-dimethylhydantoin) 1,3-dichloro-5- methyl-5-isobutylhydantoin; 1,3-dichloro-5-methyl-5 ethylhydantoin; 1,3 dichloro-S,S-diisobutylhydantoin; 1,3- dichl0ro-5-methyl-S-n-amylhydantoin, and the like. Other useful hypochloriteliberating agents are trichloromelamine and dry, particulate, water-soluble anhydrous inorganic salts such as lithium hypochlorite and calcium hypochlorite. The anti-spotting agent is generally employed in an amount on the order of about 0.5 to 5% of the final composition.

It is also within the broad scope of this invention to use chlorinated phosphates to supply both the hypochlorite chlorine and some phosphate. Thus one may use chlorinated trisodium phosphate (which is believed to consist of trisodium phosphate and sodium hypochlorite in intimate association in a crystalline form) containing,

for example, about 1 to available chlorine. The preparation of chlorinated trisodium phosphate is described in US. Pats. 1,555,474 and 1,965,304. When the composition contains a mixture of sodium silicate and hydrated condensed phosphate made by hydrating the condensed phosphate by blending it with liquid aqueous sodium silicate, as described previously, the chlorinated trisodium phosphate may be present during or after the hydration step. When chlorinated trisodium phosphate is used the composition should contain sufficient water (combined therewith as hydrate) to prevent this salt from decomposing.

As chelates one may employ the various aminocarboxylates, aminophosphonates and the like, examples include ethylenediamine tetraacetates (soluble salts e.g. Na, K, etc.), nitrilo triacetates, and the like. When these are used it is preferred to omit the chlorine bleach due to a possible interaction.

As organic Wetting agents or detergents it is preferred to use the low-foaming ethylene oxide condensate type of nonionic detergents. Examples thereof are the reaction products of benzyl chloride and ethoxylated alkyl phenol having the formula where R is an alkyl chain having from 6 to 12 carbon atoms and X is a Whole number from 12 to 20; polyether esters of the formula ClC H CHCO (CH CH O) R Where x is an integer from 4 to 20 and R is a lower alkyl group of not over four carbon atoms, e.g., a compound of the formula (ClC H CH-CO (CHgOHzO) CH and polyalkylene oxide condensates of an alkyl phenol, such as the polyglycol ethers of alkyl phenols having an alkyl group of at least about 6 and usually about 8 to 20 carbon atoms and an ethylene oxide ratio (number of ethenoxy groups per mole of condensate) of about 7.5, 8.5, 11.5, 20.5, 30, and the like. The alkyl substituent on the aromatic nucleus may be di-isobutylene, diamyl, polymerized propylene, isooctyl, nonyl, dimerized C -C olefin, and the like. Among other condensates with phenols is an alkylated B-naphthol condensed with 8 moles of ethylene oxide, the alkyl group having 6 to 8 carbon atoms.

[Further suitable detergents are the polyoxyalkylene esters of organic acids, such as the higher fatty acids, rosin acids, tall oil, or acids from the oxidation of petroleum, and the like. The polyglycol esters will usually contain from about 8 to about 30 moles of ethylene oxide or its equivalent and about 8 to 22 carbon atoms in the acyl group. Suitable products are refined tall oil condensed with 16 or 20 ethylene oxide groups, or similar polyglycol esters of lauric, stearic, oleic and like acids.

Additional suitable non-ionic detergents are the polyalkylene oxide condensates with higher fatty acid amides, such as the higher fatty acid primary amides and higher fatty acid monoand di-ethanol-amides. Suitable agents are coconut fatty acid amide condensed with about to 30 moles of ethylene oxide. The fatty acyl group will similarly have about 8 to 22 carbon atoms, and usually about 10 to 18 carbon atoms in such products. The corresponding suphonarnides may also be used if desired.

Other suitable polyether non-ionic detergents are the polyalkylene oxide ethers of higher aliphatic alcohols. Suitable alcohols are those having a hydrophobic character, and preferably 8 to 22 carbon atoms. Examples thereof are iso-octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl and oleyl alcohols which may be condensed with an appropriate amount of ethylene oxide, such as at least about 6, and preferably about '10- 30 moles. A typical product is tridecyl alcohol, produced by the Oxo process, condensed With about 12, or

moles of ethylene oxide. The corresponding higher alkyl mercaptans or thioalcohols condensed with ethylene oxide are also suitable for use in compositions of the present invention.

The water soluble polyoxyethylene condensates with polyoxypropylene polymers may likewise be employed in compositions of the present invention. The polyoxypropylene polymer, which is prepared by condensing propylene oxide with an organic compound containing at least one reactive hydrogen, represents the hydrophobic portion of the molecule, exhibiting sufficient water insolubility per se, at a molecular Weight of at least about 900, such as about 900 to 2400, and preferably about 1200 to 1800. The increasing addition or condensation of ethylene oxide on a given water insoluble polyoxypropylene polymer tends to increase its Water solubility and raise the melting point such that the products may be water soluble, and normally liquid, paste or solid in physical form. The quantity of ethylene oxide varies with the molecular weight of the hydrophobic unit but will usually be at least about 20% and preferably at least about 40% by weight of the product. With an ethylene oxide content of about 40 up to there are usually obtained normally liquid products, above 50% soft waxlike products, and from about 70-90% normally solid products may be obtained which can be prepared in flake form if desired. These condensates may be designated by the following structure:

Y is the residue of an organic compound which contained x active hydrogen atoms.

n is an integer x is an integer, the value of n and x being such that the molecular Weight of the compound, exclusive of E, is at least 900, as determined by hydroxy number,

E is a polyoxyethylene chain and constitutes 2090%,

by weight of the compound, and

H is hydrogen.

It is preferred to use products of the type just described having a total molecular Weight within the range 2000 to 10,000, and preferably about 4000 to 8000. A suitable material is a condensate having a typical average molecular Weight of about 7500, the hydrophobic polypropylene glycol being condensed with sufiicient ethylene oxide until a normally solid water-soluble product is obtained which has an ethylene oxide content of about -90% and a melting point usually of about 5l54 C. Another material is a liquid condensate having an ethylene oxide content of 40-50% and a molecular weight of about 4500.

Examples of other suitable wetting agents include low foaming anionic materials such as didecyl phosphate, methyl naphthalene sulfonate, sodium Z-acetamidohexadecane l-sulfonate, and mixtures thereof. Mixtures of the foregoing wetting agents may also be employed, and, if desired, foam-reducing additives may be added as appropriate to minimize undesirable foaming tendencies of these wetting agents under conditions of use.

Typically the organic wetting agent may be employed in the instant formulations in amounts up to about 3% by weight of the final composition, and preferably about 0.5 to 2.5% by weight thereof. Preferably the wetting agent used would be characterized by a foam height of less than about 50 mm. in the Ross-Miles pour foam test described by Ross and Miles in Oil and Soap, May 1941, pages 99 to 102.

Other alkaline builders and inert neutral salts may be used. These include sodium carbonate and borax as typical alkaline builders and sodium sulfate as a representative neutral salt. As a further ingredient in the formulation a suitable perfume may be included to give the formulation a pleasant odor. Since most nonionic detergents have some odor, the choice thereof should take into consideration the odor of the nonionic detergent so that it des not unduly conflict with the perfume.

A quantity of a coloring material may also be considered as yet a further ingredient. For instance acceptable coloring materials are ultra-marine blue and Heliogen green, a phthalocyamine green pigment. Naturally, the quantities employed are quite small. Other suitable additives may include small quantities, e.g., 2%, of other types of glaze attack inhibitors such as compatible proportions of sodium berylliate, aluminum acetate, sodium aluminate, and the like.

The solid materials utilized desirably should be granular preferbly having a mesh size of approximately the same size (and Within the range of about 0.074 to 0.84 mm.) in order to prevent stratification. In formulating the detergent compositions, it is important that all the ingredients be kept as dry as possible prior to mixing. The ingredients should preferably be of anhydrous grade taken from sealed containers and charged directly to a mixer. It has been found efficacious to add the anti-spotting agent to a submixture of a portion of the sodium tripolyphosphate hexahydrate and all of the sodium sulfate, when the latter is included. Since the quantity of the anti-spotting agent is usually relatively small it is often difficult to insure a complete distribution when added directly to the mixture of salts unless such a submixture is employed.

The following examples are given to illustrate this invention further.

EXAMPLE 1 In this example there is used a dry mixture of the following materials in the indicated proportions: granular anhydrous sodium metasilicate (containing 1 mol of Na O per mol of SiO 20 parts; granular sodium tripolyphosphate hexahydrate 66.85 parts; granular potas sium dichloroisocyanurate 1.6 parts; non-ionic detergent 1.5 parts; sodium fiuosilicate 8.5 parts; perfume liquid 0.02 part; Heliogen Green WND powder 0.005 part; Water 0.025 part; and sodium sulfate anhydrous 1.5 parts.

The non-ionic detergent is the product obtained by the condensation of about three mols of propylene oxide with the condensation product of one mol of a mixture of essentially straight chain, primary, fatty alcohols in the C -C range with about six mols of ethylene oxide.

The mixture is prepared from a pre-blend of (I) 90% of the phosphate, the metasilicate, the fiuosilicate and the sodium sulfate, (II) a mist of the non-ionic detergent, perfume, color and water, and (III) remaining phosphate and the KDCC.

The formulation has a pH of about 9.6 when dissolved in 0.15% and 10.2 at 1% concentration in water. It is a free-flowing powder that does not become tacky and does not lose its free-flowing property even after storage for 7 days at 140 F.

In tests in an automatic dishwasher, using the formulation in 0.15% concentration in the water it shows excellent dishwashing characteristics. In tests for 2 hours at 211 F., there is no damage to the overglaze of fine china.

EXAMPLE 2 In this example there is used a dry mixture of the following powdered materials in the indicated proportions: anhydrous sodium metasilicate 31.1 parts; sodium tripolyphosphate hexahydrate, 54.7 parts; potassium dichloroisocyanurate 1.6 parts; non-ionic detergent 1.5 parts; sodium fiuosilicate 13.8 parts.

EXAMPLE 3 Example 2 is repeated, except that the quantities of the sodium metasilicate and sodium fiuosilicate are each decreased, to 24.4 parts and 11.1 parts, respectively.

EXAMPLE 4 A mixture of hydrated pentasodium tripolyphosphate, sodium silicate (of 1.6:1 SiO :Na O mol ratio) and chlorinated trisodium phosphate is made by blending the sodium silicate (as an aqueous liquid of 51% concentration) with the sodium tripolyphosphate (in anhydrous powdered condition) to hydrate the tripolyphosphate and form a granular product, followed by addition of the chlorinate trisodium phosphate, to produce a composition having a water content of about 15.5%, a pentasodium tripolyphosphate content of about 52.5%, as anhydrous but in product as hexahydrate (68%), a chlorinated trisodium phosphate content of about 15.5%, and a sodium silicate content of about 16.5%. 100 parts of this composition is then blended with 5.5 parts of powdered sodium fiuosilicate and 1.5 parts of the non-ionic detergent used in Example 1.

In the foregoing examples, the temperature is room temperature unless otherwise indicated except that in the hydration steps a moderate temperature rise occurs. In the examples the materials used have the following preferred specifications:

SODIUM TRIPOLYPHO SPHATE IIEXAHYDRATE U.S. Screen N0.

Tin-u On Percent 10 Nil.

10 20 Smax. 20 30 15-35.

10 60 min. 5 max.

Sodium metasilicate-On U.S. No. 20 0.6% max. thru U.S. No. 100 0.8% max. Sodium sulfateFine powder Sodium fiuosilicate-Fine granular material KDCC On U.S. No. 20nil On U.S. No. 100-99% min.

1 ent, in an automatic dishwasher. When the dishwasher is set into operation, after the dishes have been suitably positioned therein, the automatic devices of the dishwasher permit the addition of sufficient water to produce a concentration of the detergent composition of approximately 0.3% by weight. The operation of the dishwasher results in treating, that is, washing of the dishes with the aqueous solution of the detergent composition. Usually, the sequence of operation in utilizing an automatic dish- Washer results in one or more rinsing steps following the one or more washing cycles. In utilizing the detergent composition of the present invention it will be noted that even after use in a considerable number of washings there will be little or no attack on the overglaze of china or little or no tarnishing of silver or silver plate as a result of the use of the detergent composition.

Typically the dishwashing is effected at temperatures above F., uusally about -160 F., e.g. F. or F., using washing time of about 10 minutes (two five minute washes and two rinses).

In the above description, the use of a chlorine bleach has been exemplified and specifically mentioned as an anti-spotting agent. It is clear that these materials also generally function as excellent stain removal materials. For the latter purpose, one may also employ conventional oxygen bleach compounds, e.g., sodium perborate, potassium persulfate and the like.

We claim:

1. In a water soluble alkaline dishwashing detergent composition consisting essentially of to 70% of a soluble alkaline phosphate and about to 50% of an alkali metal silicate in which the mole ratio of SiO :Na O ranges from 1:1 to 3.2:1, the improvement which comprises the inclusion in said composition as at least part of the alkali metal silicate component, at least 2% of a fluosilicate hydrolyzable in a hot basic solution of a pH above 7 to act as an overglaze protector for overglazed china during the washing with said composition.

2. A composition as in claim 1 wherein the fluosilicate is selected from the group consisting of the fluosilicate of sodium, potassium, lithium, aluminum, zinc and beryllium.

3. A composition as in claim 1 and including a dry water-soluble anti-spotting agent which, on contact with water, liberates hypochlorite chlorine.

4. A composition as in claim 1 in which the proportion of said alkali metal silicate is about to and the proportion of said fluosilicate is about 2 to 15%.

5. A composition as in claim 1 in which the alkali metal silicate is solid sodium metasilicate, the phosphate is sodium phosphate wherein the P O :Na O mole ratio is about 0.7:1 to 3:1, and the amount thereof ranges from about to about and the fluosilicate is an alkali metal fluosilicate.

6. A composition as in claim 5 wherein the fluosilicate is sodium fluosilicate.

7. A composition as in claim 5 in which the phosphate is pentasodium tripolyphosphate.

8. In the process for automatic dishwashing in which the dishes are subjected to hot Water containing dissolved detergent composition consisting essentially of a soluble alkaline phosphate and an alkali metal silicate, the im provement which comprises the inclusion in said composition of a hydrolyzable fluosilicate in which the mole ratio of siO zNa O ranges from 1:1 to 32:1 in amount sufficient to act as an overglaze protector for overglazed china during washing with with said composition.

References Cited UNITED STATES PATENTS 3,128,250 4/1964 Lintner 25299 3,255,117 6/1966 Knapp et a1. 25299 3,410,804 11/1968 Walsh 25299 3,494,868 2/1970 Gray 25299 MAYER WEINBLATT, Primary Examiner U.S. Cl. X.R. 2388