US3829386A

US3829386A - Surfactant-foam depressant emulsion compositions

Info

Publication number: US3829386A
Application number: US00297803A
Authority: US
Inventors: W Wegst; O Aepli
Original assignee: BASF Wyandotte Corp
Current assignee: Diversey Wyandotte Corp; BASF Corp
Priority date: 1969-10-15
Filing date: 1972-10-16
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13
Also published as: NL7014942A; NL156186B; GB1297087A; DE2050768A1

Abstract

EMULSIONS OF SILICONE-BASED FOAM DEPRESSANTS DISPERSED IN A LOW CLOUD POINT LIQUID NONIONIC SURFACTANTS AND INCORPORATED INTO ALKALINE DETERGENT COMPOSITIONS TO PROVIDE IMPROVED DETERGENT COMPOSITIONS WHICH OBVIATE THE NEED FOR THE ADDITION OF SUPPLEMENTAL FOAM DEPRESSANTS DURING CONTINUOUS WASH OPERATIONS. THE EMULSIONS OF THE PPRESENT INVENTION GENERALLY COMPRISE FROM ABOUT 10 TO 50 PERCENT BY WEIGHT OF SURFACTANT. THEY ARE STABLE OVER A PERCENT BY WEIGHT OF SURFACTANT. THEY ARE STABLE OVER A WIDE TEMPERATURE AND CONCENTRATION RANGE AND CAN EASILY BE INCORPORATED INTO SOLID ALKALINE DISHWASING AND DETERGENT COMPOSITIONS IN EFFECTIVE CONCENTRATION OF FROM 1 TO 5 PERCENT BY WEIGHT OF THE TOTAL COMPOSITIONS. THE COMPOSITIONS EMPLOYING THE EMULSION ARE USEFUL IN BOTH INDUSTRIAL AND DOMESTIC WASH OPERATIONS.

Description

United States Patent 3,829,386 SURFACTANT-FOAM DEPRESSANT EMULSION COMPOSITIONS Walter F. Wegst, Grosse lle, and Otto T. Aepli, Southgate, Mich., assignors to BASF Wyandotte Corporation, Wyandotte, Mich.

No Drawing. Continuation of abandoned application Ser. No. 866,715, Oct. 15, 1969. This application Oct. 16, 1972, Ser. No. 297,803

Int. Cl. Clld 3/06, 3/16 U.S. Cl. 252135 4 Claims ABSTRACT OF THE DISCLOSURE Emulsions of silicone-based foam depressants dispersed in low cloud point liquid nonionic surfactants are incorporated into alkaline detergent compositions to provide improved detergent compositions which obviate the need for the addition of supplemental foam depressants during continuous wash operations. The emulsions of the present invention generally comprise from about 10 to 50 percent by weight of depressant and from about 50 to 90 percent by weight of surfactant. They are stable over a wide temperature and concentration range and can easily be incorporated into solid alkaline dishwashing and detergent compositions in effective concentration of from 1 to 5 percent by weight of the total compositions. The compositions employing the emulsion are useful in both industrial and domestic wash operations.

This is a continuation of application Ser. No. 866,715, filed Oct. 15, 1969, now abandoned.

The present invention relates to detergent formulations and foam depressants therefor. More particularly, the present invention concerns emulsions of a silicone-based foam depressant dispersed in a low cloud point liquid nonionic surfactant and the improved detergent formulations resulting from the use thereof.

Aqueous solutions of alkaline detergent formulations which include various water treating compounds are widely employed for cleaning food handling and processing equipment, eggs, textiles, plastics and similar solid substrates. However, continual usage of the alkaline detergent is limited because of foams produced by the interaction between the detergent and the soil deposits sought to be removed, such as, residues from eggs, milk and other fatty or proteinaceous matter.

The foam problem is somewhat alleviated by the addition of a surfactant, usually a low cloud point nonionic surfactant, to the detergent formulation. The addition of this type of surfactant to an alkaline detergent formulation greatly enhances the wetting and emulsification of soil residues sought to be removed. Furthermore, by vir tue of the fact that these surfactants are essentially insoluble at elevated temperatures of about 120 to 180 F., they depress or suppress the foam developed by the interaction of the alkaline materials in the detergent and the soil deposits. Additionally, since these surfactants are soluble at low temperatures of about 60 to 100 F., they contribute to the ready rinsing of cleaned surfaces with cool or tepid water to provide substrates or surfaces free of standing droplets or water breaks.

During continuous cleaning operations, however, oftentimes, the surfactant will contribute to and develop excessive foams which interfere with spraying, rinsing and pumping operations thereby causing objectionable overflows. When these objectionable conditions arise, it has become the practice to add a supplemental foam depressant, usually silicone-based, to the aqueous detergent solution. This step in the operation requires personal attention thereby resulting in man-hour expense. Furthermore, if too much depressant is employed, then the cleaned substrates may have streaked surfaces, water breaks, standing droplets and the like. However, this manipulative step is necessary because attempts to incorporate silicone-based foam depressants directly into a1- kaline dishwashing and detergent formulations have been unsuccessful. Although freshly prepared silicone-containing formulations are quite acceptable, it appears that after a few Weeks of aging, the alkaline materials react with and decompose the silicones, thereby negating their efficacy in the formulation.

It is therefore an object of the present invention to provide an improved solid alkaline detergent formulation having a foam depressant incorporated therein. It is another object of the present invention to provide an im proved silicone-containing solid alkaline detergent for mulation which is not susceptible to silicone degradation over extended periods of time. Still another object of the present invention is to provide an emulsion composition consisting essentially of a foam depressant in a low cloud point nonionic surfactant which is easily and advantageously employed in solid alkaline detergent formulations. It will become apparent to those skilled in the art that these and other objects are achieved by the present invention from a consideration of the following detailed description and examples thereof.

In accordance with the present invention, it has now been found that by the addition of an emulsion composition consisting essentially of (a) a silicone-based foam depressant and (b) a low cloud point nonionic surfactant, the problems heretofore associated with the addition of a silicone foam depressant into an alkaline detergent are overcome. The alkali constituent of the detergent formulation has been found not to react with and degrade the silicone-based depressant over a considerable period of time. The reasons for this phenomenon are not known, but the nonionic surfactant appears to encapsulate the silicone-based depressant thereby protecting it from the alkali constituents of the formulation. By using a surfactant as the emulsifier, additional advantages accrue to detergent formulations prepared therewith. First, the surfactant disperses the depressant in an aqueous use solution so that the depressant is not selectively skimmed olf the solution surface and washed away as overflow, thereby providing a long-lasting foam depression to the solution for extended washing periods. Secondly, the surfactant avoids production of hydrophobic surfaces, i.e., water breaks, standing droplets and the like, on the cleaned substrate or surface.

The emulsions contemplated by the present invention generally comprise about 10 to 50 percent by weight of depressant, based on the total weight of the emulsion, and from about 50 to percent by weight of surfactant, based on the total weight of the emulsion. Preferably, the emulsion comprises about 10 to 40 percent by weight of depressant and from about 60 to 90 percent by weight of surfactant. They are prepared by dispersing the depressant in the surfactant by any conventional method known in the art such as by agitation, stirring and the like.

The silicone-based foam depressants contemplated for use herein are the liquid siloxanes. These compounds, which are widely known and commercially available, generally consist of substituted or unsubstituted polyal kylsiloxanes or alkyl polysiloxanes. Typical examples of these compounds include, for example, polydimethylsiloxane, dimethyl polysiloxane and the like. All of the commercially available, non-emulsified, silicone-based siloxane foam depressants can be used with equal efficacy in the present invention.

The nonionic surfactant dispersing agents contemplated by the present invention generally comprise the normally liquid oxyalkylated adducts of hydrophobic bases. These surfactants are generally prepared by condensing, under oxyalkylation condition, an alkylene oxide having from about 2 to 4 carbon atoms, such as ethylene oxide, 1,2- propylene oxide, the butylene oxides, and the like, as well as mixtures thereof, with a hydrophobic base having at least one reactive hydrogen atom. Typical examples of such surfactants include, for example, the ethoxylated adducts of alkylphenols corresponding to the formula:

R-Owmmm wherein R is alkyl having from about 8 to 12 carbon atoms and n is an integer such that from about 50 to 80 percent by weight of the surfactant consists of ethylene oxide.

Another class of useful surfactants correspond to the formula:

2 4 )-a( 3 6 )b( 2 4 )a wherein b is an integer such that the (C H O) group has a molecular weight of from about 800 to 4000 and preferably from about 1500 to 2000; and a is an integer such that the final molecular weight of the surfactant ranges from about 2000 to 5000 and preferably from about 2500 to 4500. These surfactants and their method of preparation are more particularly described in US. Pat. No. 2,674,619.

Still another class of suitable surfactants comprises the oxyalkylated adducts of higher aliphatic alcohols and mixtures thereof. These surfactants are prepared by condensing ethylene oxide and propylene oxide, either sequentially or as a mixture, with said higher aliphatic alcohols. These surfactants are more particularly described in US. Pat. No. 3,340,309. In the practice of the present invention, it is preferred to employ surfactants selected from the latter two classes.

As noted previously, the emulsions, which are prepared by conventional methods are well known in the art, are stable over a wide range of concentrations as well as temperatures.

In accordance with the present invention, the present emulsions are advantageously employed in solid alkaline detergent formulations. These detergent formulations generally consist of from about 25 to 88 percent by weight of an alkali material such as anhydrous soda ash, the sodium phosphates, metasilicates, sodium borate, and the like, as well as mixtures thereof. To prevent scaling and water precipitates caused by the alkali in aqueous solutions, various water treating compounds are added to the by Weight of the total formulation. Because the dispersing agent for the depressant is a surfactant, further amounts of surfactant need not be incorporated into the formulation. The emulsion is added to the alkali detergent composition by any conventional mode such as a ribbon mixer or the like.

Optionally, a germicidal composition, such as [(monotrichloro)-tetra-monopotassium dichloro]penta-isocyanurate, in effective concentrations of from 1 to 10 percent by weight can also be incorporated into the formulation.

It has been observed that when silicone-based depressants are incorporated into alkali formulations in accordance with the present invention, no silicone degradation occurs over extended periods of time of at least 5 months.

The following examples which are not to be construed as being unduly limitative of the present invention set forth specific embodiments thereof. In Examples I-XI specific alkali detergent formulations advantageously em ploying the emulsion of the present invention are set forth. In all the examples, unless otherwise indicated, all parts by weight.

EXAMPLE I An alkali detergent composition was prepared which consisted of the following ingredients:

Ingredients: Parts by weight Soda ash, anhydrous 68.00 Sodium metasilicate, anhydrous 10.00 Sodium tripolyphosphate 20.00

Emulsion of 0.10 parts of dimethyl polysiloxane dispersed in 0.90 parts of a liquid nonionic surfactant 1 1.0 [(Monotrichloro) tetra monopotassium dichloro]penta-isocyanurate 1.00

The surfactant was prepared by condensing under oxyalkylation condition a mixture of higher aliphatic alcohols having from 12 to 15 carbon atoms with a mixture of propylone oxide and ethylene oxide.

EXAMPLES I I-X In each of the following examples, which are set forth in Table I, a plurality of alkali detergent compositions were prepared. In each example the foam depressant and surfactant were introduced into the composition as an emulsion in accordance with the present invention. The surfactant employed was the same as that described in Example I. The germicidal ingredient was again, [(monotrichloro) tetra monopotassium dichloro]pentaisocyanurate.

TABLE I Ingredients, in parts Emulsion composition Sodium Sodium tripoly- Dirnethyl Soda ash nietasilicate, phosphate, poly- Nonionic anhydrous anhydrous anhydrous siloxane surfactant Getmicide alkali in weight concentrations ranging from about 10 to percent of the total weight of the formulation. Representative of these compounds is, for example, the alkali polyphosphates which are the most predominantly employed water treating compounds.

The emulsion of the present invention is employed in a typical alkaline detergent formulation in a concentration ranging from about 1 to 5 percent by weight of the total formulation, preferably from about 1 to 3 percent The above formulations, in Examples II-X, set forth detergent formulations, which contain from 1% to 5% by weight of the emulsion, the emulsions consisting of from 10 to 50% by weight of depressant and from 50 to by weight of surfactant. It has been found that within these defined ranges, a proper balance between depressant and surfactant and between surfactant and alkali is obtained.

5 EXAMPLE x1 An alkali detergent composition was prepared by mixing together the following ingredients:

Ingredient: Parts by weight Soda ash, anhydrous 67.6 Sodium metasilicate, anhydrous 10.0

Emulsion of 0.4 part of dimethyl polysiloxane and 1.0 part of a nonionic surfactant 1 1.4 Sodium tripolyphosphate, anhydrous 20.0 Germicide 2 1.0

1 The surfactant was the same as employed in Example I. The germicide was the same as employed in Example I. A freshly prepared sample of this composition was then tested for foam control by the procedure described here inafter. Fifty ml. of a 0.8% by weight aqueous solution of the composition was placed in a 250 ml. graduated cylinder maintained at 120 F., and was manually shaken for 30 seconds. The foam produced by shaking was then measured. Thereafter, this procedure was repeated, except that one drop of homogenized whole egg was added to the solution. After hand shaking, the foam height pro duced was observed and recorded. This procedure was repeated a plurality of times for various dropwise incre ments of whole egg addition to the solution. The results from these tests are tabulated below in Table II.

TABLE II No. of drops of whole egg: Foam height, in ml. 0 1 0 2 Trace 3 Trace 5 5 8 12 30 The procedure outlined above was then repeated using a 0.4% by weight aqueous solution of the composition. The results of these foam height tests using the 0.4%

Twenty-two and one-half weeks later, the same 0.8% and 0.4% aqueous use solutions as employed above were retested for foam height production to determine if silicone degradation had occurred. The results from these tests are tabulated below in Table IV.

TABLE IV Number of drops 0.8% aqu ous solution, 0.4% aqueous solution, of whole egg foam height, in ml. foam height, in ml.

0 0 0 0 Trace 0 5.0 3 14. 0 5 21. 5 7 31. 0

It can be seen from a comparison of Table IV with Tables II and III, that after 22.5 weeks the silicone depressant had been subjected to little or no degradation, thereby evidencing the storage stability of detergent formulations prepared in accordance with the present invention.

What is claimed is:

1. A method for preventing the degradation of silicone based foam depressant in a solid alkaline detergent composition consisting essentially of:

(a) from about 25 to 88 percent by weight of an alkali material selected from the group consisting of soda ash, sodium metasilicate, sodium phosphate, sodium borate and mixtures thereof;

(b) from about 10 to 60 percent by weight of a water treating compound which is an alkali metal polyphosphate; and

(c) from about 0.1 to 2.5 percent by weight of a silicone based foam depressant selected from the group consisting of polydimethylsiloxane and dimethyl polysiloxane,

by the method of (l) dispersing the silicone based foam depressant of ingredient (c) above in a nonionic liquid surfactant to form an emulsion of said depressant and said surfactant, said emulsion containing from about 10 to 50 percent by weight of said depressant and from about 50 to 90 percent by weight of said surfactant; said nonionic liquid surfactant being selected from the group consisting of:

(i) the ethoxylated adducts of alkylphenol corresponding to the formula:

wherein R is alkyl having from about 8 to 12 carbon atoms and n is an integer such that the ethylene oxide constitutes from about 50 to percent by weight of the surfactant,

(ii) a surfactant corresponding to the formula:

wherein b is an integer such that the (C H O) group has a molecular weight of from about 800 to 4,000 and a is an integer such that the final molecular weight of the surfactant ranges from about 2,000 to 5,000, and

(iii) the water-soluble cogeneric mixture of ethylene oxide and propylene oxide adducts of higher aliphatic alcohols, and

(2) mixing with solid alkaline detergents ingredients of (a) and (b) above in such proportion that from about 1 to 5 percent by weight of above said solid alkaline detergent is said emulsion of (1) above.

2. The method of claim 1 wherein said emulsion contains from about 10 to 40 percent by weight of said depressant and from about '60 to percent by weight of said surfactant.

3. The method of claim 2 wherein said emulsion is from about 1 to 3 percent by weight of said solid alkaline detergent.

4. The method of claim 1 wherein said surfactant .of said emulsion being free of an aromatic component.

References Cited UNITED STATES PATENTS 3,250,727 5/1966 Noll et al. 252358 3,329,625 7/1967 Hoxie 252358 3,336,231 8/1967 Marsh et al 252545 3,421,940 1/1969 Wedell et al. 13429 FOREIGN PATENTS 525,433 5/1956 Canada. 1,454,789 5 1966 France.

841,257 7/ 1960 Great Britain.

LEON D. ROSDOL, Primary Examiner P. E. WILLIS, Assistant Examiner US. Cl. X.R.