United States Patent 0 1

3,355,390 METHGD FOR PREPARING HOMOGENEOUS

DETERGENT SLURRY Edwin L. Behrens, Cincinnati, Ohio, assignor to The

Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio

No Drawing. Filed Dec. 6, 1965, Ser. No. 511,985 7 ‘Claims. (Cl. 252-137)

ABSTRACT OF THE DISCLOSURE Process for preparing a homogeneous detergent slurry

comprising the steps of (a) preparing an aqueous slurry comprising water, an alkylene oxide-containing nonionic synthetic detergent and the trisodium salt of nitrilotri acetic acid; and thereafter (b) adding and mixing homo genously therein sodium tripolyphosphate.

This invention pertains to a novel method for pre paring a homogeneous detergent slurry comprising a non ionic synthetic detergent and an hydratable inorganic builder salt. More particularly, this invention relates to a method for preparing a smooth, readily pumpable aque ous detergent slurry which comprises mixing together in a critical proportion and in a critical sequence of steps, an alkylene oxide-containing nonionic synthetic detergent, an hydratable inorganic water-soluble alkaline builder salt, a watensoluble salt of nitrilotriacetic acid and water.

Prior to this invention, it had not been possible to in coporate an alkylene oxide-containing nonionic synthetic detergent into a detergent slurry without encountering some mixing and emulsion stability problems. Detergent slurries, or crutcher mixes as they are sometimes termed, which contain these nonionics, even in amounts as small as about 1.0% by weight of the ?nal detergent slurry, have a tendency to resist homogenization. Such a ?nal detergent slurry or crutcher mix is generally a viscous, heterogeneous mass. This problem is markedly accentuated by the presence in the detergent slurry of hydratable in organic builder salts such as alkali metal pyrophosphates and polyphosphates. As these salts are added to the slurry, they appear to take up water, as water of hydration, from the slurry or induce such phase transformations that the entire slurry attains a heterogeneous, clabber-like or grainy consistency. Additionally, the slurry may sepa rate into layers. The slurry or crutcher mix usually be comes very viscous and is unpumpable when ordinary water levels of from about 25% to about 40% are being utilized. ‘These complex phase and stability problems have represented obstacles to attempts to heat dry, e.g., spray dry, such a detergent slurry and thereby convert it into a satisfactory granular built detergent product. This prob lem exists independently of the other materials present in the ordinary detergent slurries such as anionic syn thetic detergents, silicates, sulfates and the like.

Accordingly, it is an object of this invention to provide a process for preparing an easily pumpable, homogeneous detergent slurry containing an alkylene oxide-containing nonionic synthetic detergent and an hydratable inorganic Water-soluble alkaline builder salt. Another object of this invention is to provide a process for preparing a homogeneous detergent slurry which can be readily em ployed in a spray drying operation employing typical processing conditions. It is also an object to provide such an improved process which utilizes a compound which not only solves the complex phase problems but also con tributes to the overall cleaning performance of the ?nal spray-dried granular detergent product.

Still further objects and the entire scope of applicability

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3,355,39? Piatented Nov. 28, 1967

2 of the present invention will become apparent from the detailed description given hereinafter. It should be under stood, however, that the detailed description and speci?c examples, while indicating preferred embodiments of the invention, are given by way of illustration only since various changes and modi?cations within the spirit and scope of the invention will become apparent to those skilled in the art.

It has now been discovered that the foregoing objects of the present invention can be obtained by a process which comprises the steps of

(a) mixing, by weight of the ?nal detergent slurry, from about 25% to about 40% water, from about 1% to about 20% of an alkylene oxide-containing nonionic syn thetic detergent, and from about 1% to about 50% of a water-soluble salt of nitrilotriacetic acid, said salt of nitrilotriacetic acid being added in an amount suf?cient to provide an easily pumpable, homogeneous slurry but in an amount less than its own solubility in the ?nal slurry, and thereafter,

(b) adding and mixing homogeneously therein to form the ?nal slurry, from about 5% to about 60% of an hy dratable inorganic water-soluble alkaline builder salt, the amount of said builder salt being not more than about ?ve times the weight of said water-soluble salt of nitrilo triacetic acid. The essential ingredients in the process of this inven

tion are water, alkylene oxide-containing nonionic syn thetic detergents, the Water-soluble salts of nitrilotriacetic acid, and the hydratable inorganic builder salts. As men tioned above, the problem solved by the process of this invention was initially caused by mixing the speci?c non ionic synthetic detergents with the hydratable builder salts in an aqueous detergent slurry. It was immaterial whether the nonionic detergent was added to a mixture of Water and the hydratable builder or whether, alter natively, the hydratable builder was added to a mixture of water and the nonionic detergent. It is signi?cant to note, however, that once the complex detergent slurry be came viscous and clabber-like, it was not rendered smooth and homogeneous by subsequently adding even large amounts of water. The surprising aspect of the present invention is that the water-soluble salts of nitrilotriacetic acid, when utilized in the critical addition sequence here inafter de?ned, do successfully solve this problem. The essential ingredients of the present invention will be de ?ned at this juncture in order to facilitate a better under standing of the critical addition sequence which will be de?ned hereinafter. The nonionic synthetic detergents which are utilized in

the process of this invention are alkylene oxide-containing nonionic detergents. They can be broadly de?ned as com pounds produced by the condensation of alkylene oxide (hydrophilic in nature) with an organic hydrophobic com pound, which can be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between the hydrophilic and hydrophobic elements.

Suitable alkylene oxide-containing nonionic synthetic detergents of the type which are useful in this embodi ment of the present invention are:

(1) The polyethylene oxide condensates of alkyl phe nols and dialkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain con?guration, with ethylene oxide, the said ethylene oxide being present in amounts equal to about 5 to 30 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may

3,355,390 be derived from polymerized propylene, diisobutylene, octene, or nonene, for example.

(2) Alkylene oxide-containing nonionic detergents de rived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. Here again, a series of compounds are contemplated whose characteristics can be controlled by achieving a desired balance between the hydrophobic and hydrophilic elements. For example, compounds con taining from about 40% to about 80% polyoxyethylene by weight and having a molecular weight of from about 5,000 to about 11,000 resulting from the reaction of ethylene oxide groups with a hydrophobic base con stituted of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of the order of 2,500 to 3,000, are satisfactory.

(3) The condensation product of aliphatic alcohols having from 8 to 22 carbon atoms, in either straight chain or branched chain con?guration, with ethylene oxide, e.g., a coconut alcohol-ethylene oxide condensate having from about 4 to 45, preferably from 5 to 20, moles of ethylene oxide per mole of coconut alcohol. The coco nut alcohol fraction which is preferred is a distilled coconut alcohol having from 10 to 16 carbon atoms, with the approximate chain length distribution being from 2% C10, 66% C12, 23% C14, and 9% C16. Another pre fered compound is the condensation product of tallow derived alcohol and from about 5 to about 15 moles of ethylene oxide per mole of tallow alcohol; a speci?c illus tration being the condensation reaction product of one mole of tallow alcohol and 10 moles of ethylene oxide (T510)

(4) A well known class of alkylene oxide-containing nonionic synthetic detergents of this type is made avail able on the market under the trade name of “Pluronic.” These compounds are formed by condensing ethylene ox ide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydro phobic portion of the molecule which, of course, ex hibits water insolubility, has a molecular weight of from about 1500 to 1800. The addition of polyoxyethylene radicals to this hydrophobic portion tends to increase the water solubility of the molecule as a whole and the liquid character of the product is retained up to the point where polyoxyethylene content is about 50% of the total weight of the condensation product. The molecu lar weights of Pluronic L61, L64, and F68, for example, are approximately 2000, 3000 and 8000 respectively.

Speci?c illustrations of the foregoing classes include the following which are merely illustrative of the type in tended: nonyl phenol condensed with either about 5 or about 30 moles of ethylene oxide per mole of phenol and the condensation product of coconut alcohol with an average of either about 4 or about 15 moles of ethylene oxide per mole of alcohol and the condensation product of about 15 moles of ethylene oxide with one mole of tridecanol. Other illustrative examples are dodec ylphenol condensed with 12 moles of ethylene oxide per mole of phenol; dinonylphenol condensed with 15 moles of ethylene oxide per mole of phenol; dcdecyl mercap tan condensed with 10 moles of ethylene oxide per mole of mercaptan; nonyl phenol condensed with 20 moles of ethylene oxide per mole of nonyl phenol; myristyl alco hol condensed with 10 moles of ethylene oxide per mole of myristyl alcohol; lauramide condensed with 15 moles of ethylene oxide per mole of lauramide; and di isooctylphenol condensed with 15 moles of ethylene oxide. The water-soluble salts of nitrilotriacetic acid have the

general formula CHzCOOH

N-CHzCO OH

CHzC O OH

wherein a suitable cation is substituted for the acidic hydrogens in’the above formula, the cation being sodium;

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4 potassium, other alkali metals, or ammonium or substi tuted ammonium radicals, e.g., triethanol amine. The tri sodium salt of nitrilotriacetic acid (Na3NTA) is the pre ferred water-soluble salt of nitrilotriacetic acid for use in this invention. The water-soluble salts of nitrilotri acetic acid will be referred to generally in the following description as NTA. The hydratable water-soluble inorganic alkaline builder

salts of this invention are preferably the sodium and potassium salts of tripolyphosphoric acid, that is, sodium tripolyphosphate and potassium tripolyphosphate. Other water-soluble salts of tripolyphosphoric acid can be em ployed such as those utilizing other alkali metals as the cation or a cation chosen from ammonium or substituted ammonium radicals. Sodium pyrophosphate and potas sium pyrophosphate can also be utilized in the process of this invention. The most preferred inorganic builder salt for use’ in this invention is anhydrous sodium tri polyphosphate (STP).

It is contemplated that the detergent slurry of this invention can contain ordinary detergent additives as described hereinafter. It is understood, however, that these additives are not necessary to the successful prac tice of the invention herein described. Because these nonessential ingredients may be present, the term “slurryj’, as hereinafter used, is de?ned to include water per se or water in admixture with any or all of the other additives hereinafter set forth regardless of whether those addi tives are dissolved in or dispersed in the water. ,

In order to obtain the bene?ts of this invention a hereinbefore outlined, the essential ingredients described above must be combined in the following critical se quence of steps.

In the ?rst step of the process of this invention, a detergent slurry is prepared which contains water, the nonionic detergent and the NTA. Preferably, the NTA is ?rst mixed with the detergent slurry, e.g., water, and then the nonionic detergent is added. Alternatively, the nonionic can be mixed with the detergent slurry ?rst and then the NTA can be added to this mixture; but for reasons given below, the former sequence is highly pre ferred.

According to a preferred embodiment, the NTA should be added to the slurry before the alkylene oxide-contain ing nonionic synthetic detergent. If the nonionic is added to the slurry ?rst, the resulting mixture tends to separate into layers, thicken and take on a grainy appearance. With the subsequent addition of NTA, however, homo geneity is again attained and viscosity is again reduced. To prevent this separation and increase in viscosity in the mixture, it is highly preferred that NTA be added to the slurry before the nonionic. The water-soluble salts of nitrilotriacetic acid, previ

ously described, serve the purpose of homogenizing and ?uidizing the detergent slurry and, additionally, continue‘ to maintain the slurry in a smooth, ?uid and homogeneous state throughout the subsequent addition of the nonionic detergent and especially through the critical addition of the hydratable inorganic builder salts. The addition of NTA prior to the hydratable inorganic builder salt is the essence of the process of this invention. If the hydratable builder salt is added before or along with the NTA, the slurry sets up into an unpumpable mass, i.e., it becomes grainy and clabber-like. The unpumpable condition of the slurry makes mixing virtually impossible, thereby pre cluding the preparation of a homogeneously blended slurry on the subsequent addition of NTA and the non ionic detergent. The addition of NTA after the hydratable builder salt does not restore the slurry to the smooth, pumpable, homogeneous slurries which are desirable and which are produced by the process of this invention, nor will the further addition of water convert the mass into a homogeneous, pumpable mixture. It has been discovered that if the NTA is ?rst mixed with the nonionic detergent,

75 the subsequent addition of the hydratable builder salt,

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e.g., STP, does not adversely affect the desired homoge neity of the slurry. The only perceptible change in the slurry is a gradual and expected increase in viscosity upon the addition of the hydratable builder salt.

In connection with this invention, it is also important to note that the NTA should not under any circumstances be added in excess of its solubility in the ?nal detergent slurry as, at these concentrations, its effectiveness de creases rapidly. If NTA is added in excess of its solubility, the detergent slurry behaves, in some instances, as if no NTA was present at all. In all such cases, the homogeniz ing and ?uidizing effects of the NTA are markedly re duced, NTA, in addition to its main function in this process

of homogenizing and ?uidizing the detergent slurry, also exhibits synergistic builder action in a ?nal heat dried, i.e., spray dried, detergent product when combined with alkaline salts of tripolyphosphon'c acid in a preferred weight ratio of NTA to the tripolyphosphoric acid salts of from about 3:1 to about 1:5. (These ratios are cal culated on the basis of NaaNTA and Na5STP.) The syn ergistic ‘builder action of NTA and the alkaline salts of tripolyphosphoric acid is more fully explained in copend ing patent application by Gedge, Ser. No. 498,908, ?led October 11, 1965.

It was totally unexpected that an organic salt having synergistic builder capabilities, i.e., NTA, could be uti lized to alleviate the processing problems attributed to another known builder such as the hydratable inorganic builder salts hereinbefore de?ned. Additionally, it is sur prising that the order of addition of NTA to the crutcher mixture should be so important that if deviations in the sequence occur, the problem is not solved. It is also quite unexpected that the addition of NTA in excess of its solu bility, but in the critical sequence herein de?ned, to a detergent slurry containing in its ?nal form an alkylene oxide-containing nonionic and a hydratable iorganic builder salt will not inhibit the formation of a grainy, viscous, unpumpable slurry.

In the process of this invention, the preferred nitrilo triacetic acid salt is the trisodiurn salt (NagNTA). In a further preferred embodiment of this invention, NasNTA is utilized in the slurry in an amount, by weight of the final detergent slurry, of from about 2% to about 30%. Within this preferred range, the NagNTA is generally entirely soluble in the ?nal detergent slurry and yet is present in such amounts as to adequately prevent the formation of the hereinbefore described heterogeneous, grainy, unpumpable slunies. As another preferred embodiment of this process, Water

comprises, by weight, from about 30% to about 38% of the ?nal slurry. The water can be added in conjunction with nonessential ingredients, as hereinafter described, i.e., an aqueous solution of silicates, water of hydration, aqueous anionic pastes or the like, or the water can be admixed directly with the NTA or the nonionic detergent. In any event, enough water must be added to form a pumpable slurry.

According to a preferred procedure, the nonionic deter gent is added to the NTA-Water slurry in amounts ranging from about 1% to about 20% by weight of the ?nal deter gent product. The preferred range for the addition of the nonionic is from about 2% to about 15% by weight of the ?nal detergent product. The nonionic is added to and homogeneously mixed

with the detergent slurry. Although the nonionic can be added prior to the NTA without adverse effect on the ?nal slurry, intermediate effects are noticeable. As men tioned earlier, the nonionic-containing aqueous mixture may thicken, separate into layers, or take on a grainy appearance. Although subsequent addition of NTA will, in most cases, cause the slurry to again become homo geneous and less viscous, considerable e?iort and mixing time must be devoted to such end. It is, therefore, highly

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6 preferable that the nonionic be added after the NTA has been mixed with the slurry.

After the nonionic detergent, NTA and water have been admixed into a homogeneous slurry, the hydratable builder salt is then added to the detergent slurry. The builder salt is added to and homogeneously dispersed throughout the slurry while the mixture is adequately stirred. From about 5% to about 60% of the final deter gent slurry can be comprised of the hydratable inorganic builder salts hereinbefore described. The amount of the hydratable inorganic builder salt should not, however, exceed about ?ve times the amount by weight of NTA utilized in this process. If this limit is exceeded, the slurry tends to become grainy and layered; in some instances, the slurry will become unpumpable. The entire mixing operation of this invention can be

accomplished at temperatures between about 65° F. and 200° F. It has, however, been found especially bene?cial to employ temperatures from 100° F. to 160° F. Within this preferred temperature range, the ?nal slurry is at a 'su?iciently high temperature to facilitate ordinary spray drying procedures. The slurry is, however, not hot enough to subject the hydratable inorganic builder salts to hydro lytic degradation.

‘The resultant slurry prepared by the process taught herein is smooth and homogeneous. No layering of the various detergent ingredients can be discerned. The slurry is pumpable and suitable for spray drying. Excellent deter gent granules can be obtained by spray drying this ?nal detergent slurry. Although not essential to the process of this invention,

the detergent slurry contemplated in this invention can contain detergent substances such as soap, anionic syn thetic non-soap detergents, nonionic synthetic detergents of the amine oxide and phosphine oxide type, ampholytic synthetic detergents and zwitterionic synthetic detergents, and mixtures thereof. The addition of these detergent substances forms no limitation on this invention, but is intended to be includable within the terms of claims calling for a detergent slurry comprising various detergent ingredi ents in accordance with the teachings herein. Ordinarily such optional ingredients are added to the slurry early in the process, preferably before or along with the NTA. Examples of suitable soaps are the sodium, potassium

and alkylolammonium salts of higher fatty acids (CW C20). Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium tallow and coco nut soap.

=The other suitable detergent substances are outlined at more length as follows:

(a) Anionic synthetic non-soap detergents can be broadly described as the water-soluble salts, particularly the alkali metal salts, of organic sulfuric reaction products having in their molecular structure an alkyl radical con taining from about 8 to about 22 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. (Included in the term alkyl is the alkyl portion of higher acyl radicals.) Impor tant examples of the synthetic detergents which form a part of the preferred compositions of the present inven tion are the sodium or potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8—C18 carbon atoms) produced by reducing the glycen'des of tallow or coconut oil; sodium or potassium alkyl benzene sulfonates, in which the alkyl group contains from about 9 to about 15 carbon atoms, including those of the types described in United States Letters Patents Numbers 2,220, 099 and 2,477,383 (the alkyl radical can be a straight or branched aliphatic chain); sodium alkyl glyceryl ether sulfonates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; so dium or potassium salts of sulfuric acid esters of the

3,355,399 7

reaction product of one mole of a higher fatty alcohol (e.g., tallow or coconut oil alcohols) and about 1 to 6 moles of ethylene oxide; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfate with about 1 to about 10 units of ethylene oxide per molecule and in which the alkyl radicals contain from 8 to about 12 carbon atoms; the reaction product of fatty acids esteri?ed with isethionic acid and neutralized with sodium hydroxide where, for example, the fatty acids are derived from coconut oil; sodium or potassium salts of fatty acid amide of a methyl tauride in which the fatty acids, for example, are derived from coconut oil; and others known in the art, a number being speci?cally set forth in United States Letters Patent Numbers 2,486,921; 2,486,922 and 2,396, 278. Another important anionic detergent is described, by way of example only, as comprising by weight from about 30% to about 70% of Component A, from about 20% to about 70% of Component B, and from about 2% to about 15% of Component C, wherein: said Component A is a quaternary mixture of double‘ bond positional isomers of water-soluble salts of alkene l-sulfonic acids containing from about 10 to about 24 carbon atoms, said mixture of positional isomers in cluding by weight about 10% to about 25% of an alpha beta unsaturated isomer, about 30% to about 70% of a beta-gamma unsaturated isomer, about 5% to about 25% of a gamma-delta unsaturated isomer, and about 5% to about 10% of a delta-epsilon unsaturated isomer;

said Component B is a mixture of water-soluble salts of bifunctionally-substituted sulfur-containing saturated ali phatic compounds containing from about 10 to about 24 carbon atoms, the functional units being hydroxy and sulfonate radicals'with the sulfonate radical always being on the terminal carbon and the hydroxyl radical being attached to a carbon atom at least two carbon atoms removed from the terminal carbon atoms; and

said Component C is a mixture comprising from about 30—95% water-soluble salts of alkene disulfonates con taining from about 10 to about 24 carbon atoms, and from about 5% to about 70% Water-soluble salts of hydroxy disulfonates containing from about 10 to about 24 carbon atoms, said alkene disulfonates containing a sulfonate group attached to a terminal carbon atom and a second sulfonate group attached to an internal carbon atom not more than about six carbon atoms removed from said terminal carbon atom, the alkene double bond being distributed between the terminal carbon atoms and about the seventh carbon atom, said hydroxy disulfonates being saturated aliphatic com compounds having a sulfonateradical attached to a terminal carbon, a second sulfonate group attached to an internal carbon atom not more than about six carbon atoms removed from said terminal carbon atom, and a hydroxy group attached to a carbon atom which is not more than about four carbon atoms removed from the site of attachment of said second sulfonate group.

(b) Nonionic synthetic detergents of the following types may be used in the process of this invention in addi tion to the alkylene oxide-containing nonionic synthetic detergents hereinbefore described:

(1) Long chain tertiary amine oxides corresponding to the following general formula, R1R2R3N—> 0, wherein R1 is an alkyl radical of from about 8 to about 18 carbon atoms, and R2 and R3 are each methyl or ethyl radicals. The arrow in the formula is a conventional representation of a semi-polar bond. Examples of amine oxides suitable for use in this invention include dimethyldodecyl amine oxide, dimethyloctylamine oxide, dimethyldecylamine ox~ ide, dimethyltetradecylamine oxide, dimethylhexadecyl— amine oxide.

(2) Long chain tertiary phosphine oxides correspond ing to the following general formula RR'R”P—>O wherein R is an alkyl, alkenyl, or monohydroxyalkyl radical rang

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8 ing from 10 to 18 carbon atoms in chain length and R’ and R" are each alkyl or monohydroxyalkyl groups con taining from 1 to 3 carbon atoms. The arrow in the for mula is a conventional representation of a semi-polar lbond. Examples of suitable phosphine oxides are: dodecyldi methylphosphine oxide, tetradecyldimethylphosphine ox ide, tetradecylmethylethylphosphine oxide, cetyldimethyl— phosphine oxide, stearyldimethylphosphine oxide, cetyl ethylpropylphosphine oxide, dodecyldiethylphosphine ox ide, tetradecyldiethylphosphine oxide, dodecyldipropyl phosphine oxide, dodecyldi (hydroxmethyl) phosphine oxide, dodecyldi (Z-hydroxyethyl) phosphine oxide, tetra decylmethyl - 2 - hydroxypropyl phosphine oxide, oleyldi methylphosphine oxide, and 2 - hydroxydodecylme'thyl phosphine oxide.

(0) Arnpholtic synthetic detergents can be broadly de- ~ scribed as derivatives of aliphatic secondary and tertiary amines, 'm which the aliphatic radical may be straight chain or branch and wherein one of the laliphatic sub stituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., car boxy, sulfo, sulfato, phosphato, or phosphono. Examples of compounds falling Within this de?nition are sodium-3 dodecylaminopropionate and sodium-3-dodecylaminopro pane sulfonate. (d) Zwitterionic synthetic detergents can be broadly de

scribed as derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radical may be straight chain or branched, and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic Water solubiliaing group, e.g., cat-boxy, sulfo, sulfato, phos phato, or phosphono. Examples of compounds falling within this de?nition are 3-(N,N-dimethyl-N-hexadecyl ammonio) propane-l-sulfonate and 3-(N,N-dimethyl-N dodecylammonio)-2-hydroxy propane-l-sulfonate which are especially preferred for their excellent cool water de tergency characteristics. The soap and non-soap anionic, nonionic, ampholytic

and zwitterionic detergent surfactants mentioned above can be used singly or in combination in the practice of the present invention. The above examples are merely spe ci?c illustrations of the numerous detergents which can ?nd application within the scope of this invention. Other surfactants Within the prescribed classes can also be used.

It will be understood by the worker skilled in the art that detergent slurries of this invention, and the detergent compositions made therefrom, will ordinarily contain various other ingredients for special purposes. Thus, the detergent slurries of this invention can contain suds build ers, bleaches, suds depressants, anti-corrosion agents, re deposition agents, dyes, ?uorescers, perfumes, sodium sul- ' fates, sodium carbonates and the like. Again, the use of any such detergent ingredients forms no limitation on the invention but is intended merely to be includable within the terms of claims calling for a detergent slurry com prising various detergent ingredients. A highly desirable, controlled sudsing, laundry deter

gent product can be obtained by incorporating from about 1% to about 15% of an anionic synthetic detergent, as hereinbefore described, into the detergent slurry of this invention. As a more preferred embodiment, the anionic synthetic detergent should ‘be added in ‘a weight ratio to the hereinbefore described essential nonionic synthetic detergent of from 3:1 to 1:6. The following examples merely serve to illustrate the

invention in speci?c detail, and when read in conjunction with the foregoing description will aid in determining the full scope of the present invention. The examples are merely illustrative and they are not in any Way intended to restrict the invention.

EXAMPLE I

Detergent slurries having the compositions shown in Table 1 were prepared in a SOO-gram, stainless steel crutcher. This crutcher was surrouned by a jacketed space

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through which water at about 135° F. ?owed continu-' ously. The crutcher was equipped with a propeller-type mixer and a thermometer. The various detergent ingredi ents were added to the crutcher in the order shown by Table 1. 5

10 drying operation. The ratio of STPzNasNTA was calcu lated on the basis of the anhydrous products.

It is apparent from Table 1 that the problem herein sought to be alleviated can be caused by a relatively small amount of alkylene oxide-containing nonionic syn

TABLE 1.—COMPOSITIONS OF DETERGENT SLURRIES

Runs 81

1 2 3 4 5 6 7 8 9

Detergent Ingredients (gms): Linear sodium alkyl benzene sulfonate paste

(hereinafter referred to as LAS paste) (alkyl moieties range from 10 to 18 carbon atoms; the paste is comprised of 53% water, 21% sodium sulfate, 26% linear alkyl benzene sulfonate) _________________________________ .1 *1 252 1 252 2 126 1 126 Z 227 2 227 ____________________________ __

Condensation reaction product of one mole of tallow alcohol and 10 moles of ethylene oxide (TElo) ______ __ 3 31. 5 3 31. 5 3 6. 3 3 6.3 1 63 7 63 7 63

Sodium Sulfate b ____ .c .c __ 4 35 4 35 4 14 4 14 3 60 3 60 1 60 Sodium silicate (SiOz. azO= 6.1) (0.435

solids) ____________________________________ __ 3 47 5 47 5 47 5 47 5 47 4 46 4 46 4 46 Trisodium nitrilotriaeetate monohydrate ' (NasNTA) __________________________________________ _. 4 38 __________ __ 6 38 __________ __ 6 38 ________ __ 5 38 5 188

Anhydrous tripolyphosphate (STP) 4 175 5 140 B 175 7 140 6 175 7 140 5 175 '1 140 ________ __ \Vater _ _ _ . _ _ _ _ . _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ . . . I. 1 70 1 67 1 14 1 l1 2 139 1 136 1 126

Weight Ratio STP:Na3NTA_ ________ _. 4:1 __________ 1. 4:1 __________ __ 4:1 ________ __ 4:1 ________ __

Approx. Slurr;7 Temp. (° F.)- 138 138 135 135 129 136 138 140 0 Slurry after addition of TE“. ________________________________________ ._ Grainy Grainy Grainy Grainy \‘ffery Grainy Grainy

iscous Slurry after addition of STP ____________________ __ Smooth Smooth Unpump- Smooth Unpump- Smooth Two Smooth Smooth

able able Phases

*Superscripts indicate order of addition. a The Slun'ies from Runs 1, 2, 4, 6, 8 and 9 were spray dried. The yield from each of these runs was about 350 grams. b Sodium sulfate added in addition to that amount present in the LAS paste.

In Runs 1 and 2, wherein no nonionic was included in the slurry, no emulsion problems were presented. The slurry was smooth, homogeneous and pumpable from the addition of the LAS paste until the ?nal addition of the STP.

In all the remaining runs, TEm was added to the slurry before NagNTA. The slurry, in all cases, became grainy and a perceptible increase in viscosity was noted. The slurry was, however, still pumpable. When no NasNTA was added to the slurry, as shown

by Runs 3, 5, and 7, the slurry became highly viscous and unpumpable With ordinary equipment useful in spray drying. In Runs 3 and 5 the slurry became so viscous that the propeller mixer was stopped. In these runs, only about three-fourths of the amount of STP indicated in Table 1 could be incorporated into the detergent slurry.

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thetic detergent (Run 5) or a relatively large amount of the nonionic (Run 7). On the basis of the ?nished spray dried product, the product of Run 5 contains about 1.8% by weight of nonionic and the product of Run 7 contains about 18% by weight of nonionic. The presence, absence or order of addition of the an

ionic, silicate and sulfate did not affect the problem.‘

EXAMPLE H

Detergent slurries having the compositions shown in Table 2 were prepared in the crutcher described in Ex ample I. Water ?owing through the jacket was main tained at a temperature of 135 ° F. In all cases, except Runs 9 and 10, the slurries described in Table 2 were spray dried. The resultant product from each spray dried run weighed about 350 grams.

TABLE 2.—COMPOSITION OF DETERGENT SLURRIES

Runs

1 2 3 4 5 G 7 8 9 10

Deterges? ___________________________________________________ .1 * 1 126 1 126 1 I26 1 126 ________ __ 2 126 263 563 563 463 531.5 531.5 631.5 531.5 463 n31.5 4% 342 342 342 442 442 342 342 342 442

379_5 279,5 279,5 279.5 379.5 379.5 479.5 479.5 279.5 379.5 5 90. 5 4 90. 5 4 144 5 181 '1 181 5 181 5 90. 5 11 90. 5 6 90. 5 7 90. 5 6815 0315 635 ____________________________ __ 787.5 787-5 587.5 587.5

1 123 1 123 1 122 1 120 1 25 2 25 2 28 2 28 1 123 1 28 1:1 1:1 1:4 ---------------------------- ~- 111 1:1 1:1 1:1 132 132 132 130 128 128 134 136 135 137

* Superscripts indicate order of addition.

The slurry, in Run 7, separated into two very viscous layers. The upper layer appeared to be largely the non lOIllC.

In the remaining runs, the addition of NaSNTA ?uid ized and homogenized the detergent slurry. The grainy, curdy appearance caused by the addition of TEm to the slurry was changed to a smooth homogeneous appear ance. The viscosity of the slurry was reduced. Upon addition of the STP, the slurry retained its smooth, ho mogeneous appearance. In all cases, the ?nal slurry was viscous, but pumpable, and suitable for use in a spray

65

70

75

Before the addition of NaaNTA in Run 1, the slurry had separated into two distinct phases. The nonionic was ?oating on the surface; the water, sodium sulfate and sodium silicate formed a curdy, grainy layer beneath the nonionic. With the addition of NagNTA to the slurry, the two phases were elminated, viscosity was decreased and the curds were broken up and dispersed..Addition of STP to the slurry resulted in only a very slight viscosity increase. The ?nal detergent slurry was smooth, homo geneous and easily pumpable. Run 2 contained exactly the same detergent ingredients

as Run 1. However, NagNTA was added to the slurry

3,355,390 1 1

before the nonionic. This slurry remained smooth, homo geneous and easily pumpable from start to ?nish. None of the problems experienced in Run 1 were experienced in Run 2. No problems were experienced in preparing the slurry

of Run 3. The addition of NaaNTA prior to the alkylene oxide-containing nonionic eliminated the problems experi enced in Run 1.

TABLE 3.—COMPOSITION

1 2 EXAMPLE 1n

Detergent slurries having the compositions shown in Table 3 were prepared in the crutcher described in Example I. Water ?owing through the jacket was main tained at a temperature of 135° F. In all cases, the slurries described in Table 3 were spray dried. The resultant product from each run weighed about 350 grams.

DETERGENT SLURRIES

Runs

1 2 3 4 5 6 7 8 9 10

etervent In edients ms. : D LES Page ______ ._(_g_...2 _______________________________________________________________ _. 126 126 126 126 126

______________________________________ ._ 31% 31% 63 31% 31% 31% __________________ ._ 42 42 42 42 42 79% 79% 79% 79% 79% 79% 45 54 37 45 54 37 133 123 140 133 123 140

Water _______________________ __ 123 123 124 124 126 29 29 28 29 29 Weight Ratio STP:Na3NTA ___________ __ 25:25 30:20 35:15 40:10 37%:12% 35:15 40:10 37%:12% 35:15 40:10 Approximate Slurry Temperature, °F__ 134 135 136 124 134 3 130 128 132 136

In Run 4 when the nonionic was added to the slurry, the slurry separated into two grainy layers. Again the nonionic was ?oating on the top of the second layer. On addition of NaSNTA, the layering etfect disappeared and the ?nal slurry was smooth and homogeneous. As the nonionic was added to the slurry in Run 5, the

slurry became very viscous. As mixing was continued, the viscosity increased until ?nally the propeller mixer would not turn. NasNTA was forced into the jelly-like slurry by hand. The slurry gradually regained its former relatively low viscosity and was pourable and pumpable. The slurries prepared in Runs 6 and 7 were smooth,

homogeneous and easily pumpable from start to ?nish. No problems were encountered in preparing the slurry.

In Run 8, the addition of TEN caused the slurry to become quite viscous and barely purnpable. Upon the addition of NasNTA, the slurry became ?uid and homo geneous. STP was added with only a very slight increase in viscosity. The ?nal slurry was smooth, homogeneous and pumpable.

In Run 9, the addition of the nonionic caused the slurry to become grainy and to separate into two phases. The addition of STP caused a sharp increase in viscosity. The slurry would not flow from the crutcher when it was inverted. The subsequent addition of NagNTA did not effect the viscosity of the slurry. The result was very viscous, unpnmpable, grainy, heterogeneous detergent mass which was not suitable for use in any ordinary detergent making process.

In Run 10, the addition of the STP caused the slurry to become grainy, clabber-like and very viscous. In attempting to incorporate TEN into the detergent mass, the high viscosity of the slurry stopped the mixer. NagNTA could not be homogeneously admixed therein. The result ant detergent mass was unpnmpable and heterogeneous. Froma comparison ofpRuns 1 through 8 it will be

observed that it is signi?cantly more advantageous to add theiNaaNTA to the detergent slurry before the addition thereto of an alkylene oxide-containing nonionic synthetic detergent. The NasNTA prevents the intermediate elfects of layering, viscosity increases and grainy slurries. The end products, however, are very similar. Runs 9 and 10, in conjunction with Runs 1 through 8,

indicate that the hydratable builder 'salt should be added after both the nonionic and NTA have been homo

V geneously admixed in the slurry to prevent the formation of heterogeneous, unpumpable detergent slurries.

30

35

45

50

55

60

65

70

75

In all runs in this example, the essential ingredients . were added to the slurry in the following order: Na3NTA, nonionic, and ?nally STP. In all cases, the slurries were smooth and homogeneous. All of these slurries were pumpable and can be used satisfactorily in a spray drying operation. Even Runs 4, 7 and 10, which formed fairly viscous slurries can still be used. A less viscous slurry than those in Runs 4, 7 and 10, however, is more desirable. Runs 5 and 8 were, likewise, quite viscous. A signi?cant factor here was that as the ratio of STPzNaaNTA de creased, the slurry ‘became less and less viscous; Pumpable as used herein in characterizing a detergent

slurry refers to the consistency or viscosity of that slurry. A desired synthetic detergent slurry at from about 30% to about 38% moisture at a temperature of about 170° F. has a viscosity of about 10,000 centipoises. This slurry is pumpable and excellent for use in ordinary spray dry ing equipment. Pumpable, as used herein, de?nes the viscosity of a detergent slurry which is suitable for use in such ordinary spray drying equipment. In no case should the viscosity of this ?nal slurry exceed 50,000 centipoises. Viscosities less than about 5,000 centipoises are not common.

EXAMPLE IV

Detergent slurries having the synthetic detergent com positions shown in Table 4 when prepared according to the procedure described below remain pumpable, smooth and homogeneous through all processing steps. The com position of the ?nal detergent slurry and the order of addition of the ingredients in each of the runs are as follows:

Grams l. Anionic Paste ___________________________ __ 126

2. Water _____ _ 28

3. Sodium Sulfate =3‘ ________________________ __ 42

4. Sodium Silicate ________________________ __ 79.5

5. Nonionic ‘ ...._ 31.5

6. Na3NTA* ______________________________ __ 90.5 7. STP * __________________________________ __ 87.5

a“ See Example I for more complete de?nition.

The ingredients are admixed into the slurry in the order shown. In all ‘cases, the slurries are smooth and homoge neous from start to ?nish. All of the slurries are pumpable and can be used satisfactorily in an ordinary spray drying operation. ,

Tetrapotassium pyrophosphate may be substituted in the above examples for the STP ingredient to Obtain comparable results.

3,855,390 13 14

TABLE 4.—SYNTHETIC DETERGENT COMPOSITOIN OF DETERGENT SLURRIES

Detergent Ingredients (gms.) Runs

10

Anionic Paste (53% Water, 21% sodium sulfate, 26% active as listed below): Sodium tallow alcohol sulfate ___________ _ _

Sosium alkyl benzene sulionate (alkyl chain contains from 9-15 carbon atoms)- _

Sodium tallow glyceryl ether su1ionate___. _ Ole?n Suli‘onate _________________________ __ Sodium alkyl phenol ethylene oxide ether sulfate containing 8 units of ethylene oxide per molecule ____________________ ..

Nonyl phenol containing 30 units of ethylene oxide per molecule ________________________ -_

Dodecyl mereaptan containing 10 units of ethylene oxide per molecule _______________ __

Dinonylphenol containing 15 units of ethylene oxide per molecule _____ _ _

Plurorn'c L64 (as described above)___ TEm (See Exampie I) _____________ __

I claim: 1. The process of preparing a homogeneous detergent

slurry comprising the steps of (a) mixing, by Weight of the ?nal detergent slurry, from about 25% to about 40% water, from about 1% to about 20% of an alkylene oxide-containing nonionic synthetic detergent, from about 1% to about 50% of the trisodium salt of nitrilotriacetic acid, said salt of nitrilotriacetic acid being added in amount su?icient to provide an easily pumpable, homogeneous slurry but in an amount less than its own solubility in the ?nal slurry; and thereafter,

(b) adding and mixing homogeneously therein to form the ?nal slurry from about 5% to about 60% of an hydratable sodium tripolyphosphate builder salt; the amount of said builder salt being not more than about ?ve times the weight of said trisodium salt of nitrilotriacetic acid.

2. The process of preparing a homogeneous detergent slurry suitable for spray drying comprising the steps of:

(a) mixing by weight of the ?nal detergent slurry, from about 25 % to about 40% water and from about 1% to about 50% of the trisodi-um salt of nitrilotriacetic acid, said salt of nitrilotriacetic acid being added in amount su?'icient to insure the formation of an easily pumpable, homogeneous slurry but in an amount less than its own solubility in the ?nal slurry;

(b) adding and mixing homogeneously therein, from about 1% to about 20% of an alkylene oxide-con taining non-ionic synthetic detergent; and thereafter

(c) adding and mixing homogeneously therein to form the ?nal slurry, from about 5% to about 60% of hydratablc sodium tripolyphosphate builder salts;

25

30

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40

45

50

the amount of said builder salts being not more than about ?ve times the weight of said trisodium salt of nitrilotriacetic acid, while

((1) maintaining the temperature of said slurry throughout its preparation at from about 65° F. to about 200° F.

3. The process of claim 1 wherein the detergent slurry comprises from about 30% to about 38% water by weight of the ?nal detergent slurry.

4. The process of claim 1 wherein the detergent slurry comprises from about 2% to about 30% of the trisodium salt of ntrilotriacetic acid by Weight of the ?nal detergent slurry.

5. The process of claim 1 wherein the detergent slurry comprises from about 2% to about 15% alkylene oxide containing nonionic synthetic detergent by Weight of the ?nal detergent slurry.

6. The process of claim 1 wherein the temperature of the slurry throughout its preparation is maintained at a temperature of between 100° F. and 160° F.

7. The process of claim 1 wherein the detergent slurry contains from about 1% to about 15% of an anionic non-soap synthetic detergent.

References Cited

UNITED STATES PATENTS 2,921,908 1/1960 McCune __________ __ 252—1 10 3,067,144 12/1960 Michaels __________ __ 252-437

3,122,508 2/1964 Grifo ____________ __ 252—135

3,303,134 2/1967 Sheu ____________ __ 252—135

LEON D. ROSDOL, Primary Examiner.

S. E. DARDEN, Assistant Examiner.