GB1572815A - Process for making detergent compositions - Google Patents

Description

(54) PROCESS FOR MAKING DETERGENT COMPOSITIONS (71) We, THE PROCTER & GAMBLE COMPANY, a corporation organised under the laws of the State of Ohio, United States of America, of 301 East Sixth Street, Cincinnati, Ohio 45202, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to the manufacture of granular laundry detergent compositions containing particulate smectite-type clay which provides simultaneous laundering and softening of textiles during conventional fabric-laundering operations.

The invention disclosed in British Patent 1,401,726 relates to fabric laundering compositions comprising: (A) granular particles which comprise (i) from 30% to 80% by weight of the granular particles of a soap compound; and (ii) from 1% to 30% by weight of the granular particles of a curddispersing agent; and (B) an impalpable smectite-type clay having an ion exchange capacity of at least about 50 meq/100 g of clay, attached to the surfaces of the granular particles; the compositions have a weight ratio of granular particles to smectite clay in the range from 20:1 to 3:1.

It is indicated in that specification that the compositions may be prepared by dry mixing the components or by dry mixing the clay and the soap based granules and spraying them with an adhesion promoting material.

Dry mixing the fine clay into spray dried detergent granules tends to cause dust and to produce a dusty product and these disadvantages can be minimised by employing a process described in B.P.

1,401,726, whereby the clay is bonded to the granules. This can be effected by agglomerating the clay and the granules.

However, because of the peculiar colloidal properties of the smectite-type clays, precautions must be taken so that the process is practicable and so that the full softening potential of the clay is preserved.

It has now been found that products having good softening and water-solubility properties and reduced dust-producing characteristics can be made by the following process.

According to the invention, there is provided a process for making a laundry detergent composition comprising: (A) granular particles which comprise (i) from 30 /n to 80% by weight of the granular particles of a soap compound; and (ii) from 1% to 30 /n by weight of the granular particles of a curd-dispersing agent; and (B) from 4% to 25 /n by weight of the composition of a smectite-type clay having an ion exchange capacity of at least 50 meq/100 g of clay, the composition having a weight ratio of granular particles to smectite clay of from 20:1 to 3:1, in which process a moving mass of impalpable smectite clay particles is sprayed with a liquid agglomerating agent selected from water, aqueous electrolyte solutions, non ionic surfactants and aqueous solutions of organic adhesives, to form free flowing clay agglomerates and thereafter said agglomerates are dry mixed with said granular particles comprising soap and curd-dispersing agent and with other particulate components, if any, of the composition.

The soap compositions made by the process of the present invention contain two essential components-granular soapbased particles and particles of an impalpable smectite-type clay material. The composition of the granular particles and the nature of the clay material is described more fully as follows.

The granular soap-based particle component of the instant laundering composition comprises two essential ingredients (1) a soap compound and (2) a curd-dispersing agent.

Soap Compound The granular particles of the instant invention comprise from 30% to 80%, preferably from 40 /n to 70%, by weight of the particles of a soap compound. Useful soap compounds include the ordinary soaps such as the sodium, potassium, ammonium and alkanolammonium salts of higher fatty acids containing from 8 to 24 carbon atoms, preferably from 10 to 20 carbon atoms.

Suitable fatty acids can be obtained from natural sources such as, for instance, plant or animalesters (e.g., palm oil, coconut oil, babassu oil, soybean oil, castor oil, tallow, whale and fish oils, grease, lard, and mixtures thereof). The fatty acids also can be synthetically produced (e.g., by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids are suitable such as rosin and those resin acids in tall oil. Naphthenic acids are also suitable. Sodium and potassium soaps can be made by direct saponification of the fats and oils or by the neutralization of the free fatty acids which are prepared in a separate manufacturing process. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium tallow soap, sodium coconut soap, potassium tallow soap, potassium coconut soap and mixtures thereof.

The Curd Dispersing Agent It is well known that the use of soap in hard water results in the formation and precipitation of insoluble fatty acid salts, more commonly referred to as lime soaps, which have a tendency to coagulate and form a sticky curd. To prevent formation of such curd in laundering solutions containing the compositions of the instant invention, the granular particles in addition to the soap component contain from 1% to 30%, preferably from 2% to 20%, by weight of the particles of a curd-dispersing agent.

Such curd dispersing agents either prevent the formation of large particles of insoluble lime soaps or prevent such soaps from flocculating so that they are flushed away with the washing or rinsing liquid and do not adhere to fabrics or to surfaces of washing vessels.

The effectiveness of particular materials as curd-dispersing agents can be ascertained by a simple procedure testing the ability of the test material to peptize lime soaps. Such a procedure is outlined in Schwartz and Perry, Surface Active Agents. Interscience Publishers, Inc., 1949 at pp. 326 and 327, and is summarized as follows: The general method consists of preparing a series of mixtures containing varying proportions of sodium oleate and the curd dispersing agent being tested. These mixtures contain approximately 10% total soap-plus-curd dispersant in distilled water.

Five milliliters of each mixture are then added to 45 milliliters of hard water (usually 200 ppm hardness as CaO). This is called the first dilution, and it usually results in a turbid but well-dispersed sol. Five milliliters of the first dilution are then added to 45 milliliters of hard water, forming the second dilution. This is a severe test since there is now more than enough lime present to precipitate all the soap. Furthermore, the total soap-plus-curd dispersant concentration is of the order of 0.1%. The results are expressed as the percentage of dispersant in the soap-curd dispersant mixture which is just sufficient to prevent flocculation on the second dilution. The more effective the curd dispersing agent, the lower is the percentage value. For purposes of the instant invention a "curd dispersing agent" is any material which produces a percentage value in the abovedescribed lime soap peptizing procedure of about 39 /n or less. A conventional non-curd dispersant surfactant for purposes of this invention is a surfactant providing a percentage value greater than 39% in the above-described lime soap peptizing procedure.

Examples of suitable curd-dispersing agents include certain anionic, ampholytic and zwitterionic materials as well as certain amides, as described below.

(I) Anionic organic detergents which are alkali metal, ammonium and substitutedammonium salts of esters of a-sulfonated fatty acids in which the esters contain 12 to 25 carbon atoms.

These detergent compounds have the following structure:

wherein R1 is an alkyl or alkenyl moiety of 10 to 20 carbon atoms (forming with the two carbon atoms a fatty acid group); R2 is alkyl of I to 10 carbon atoms; and M is a saltforming moiety.

The salt-forming moiety M in the herein before described structural formula is a water-solubilizing cation and can be, for example, an alkali metal cation (e.g., sodium, potassium, lithium), ammonium or substituted ammonium cation. Specific examples of substituted ammonium cations include methyl-, dimethyl, trimethylammonium and triethanolammonium cations and quaternary ammonium cations such as tetramethyl ammonium and dimethyl piperidinium cations and those derived from alkylamines such as ethylamine, diethylamine, triethylamine and mixtures therof.

Specific examples of this class of compounds include the sodium and potassium salts of esters where R2 is selected from methyl, ethyl, propyl, butyl, hexyl and octyl groups and the fatty acid group (Rl plus the two carbon atoms in the structure above) is selected from lauric, myristic, palmitic, stearic, palmitoleic, oleic, linoleic acids and mixtures thereof. A preferred ester material herein is the sodium salt of the methyl ester of (r-sulfonated tallow fatty acid, the term tallow indicating a carbon chain distribution approximately as follows: C14-2.5%, C16-28%, C,,230/,, Palmitoleic--2, oleic--41.5 and linoleic-3% (the first three fatty acids listed are saturated).

Other examples of suitable salts of asulfonated fatty esters utilizable herein include the ammonium and tetramethylammonium salts of the hexyl, octyl, ethyl, and butyl esters of a-sulfonated tridecanoic acid; the potassium and sodium salts of the ethyl, butyl, hexyl, octyl, and decyl esters of er-sulfonated pentadecanoic acid; and the sodium and potassium salts of the butyl, hexyl, octyl, and decyl esters of asulfonated heptadecanoic acid; and the lithium and ammonium salts of the butyl, hexyl, octyl, and decyl esters of asulfonated nonadecanoic acid.

The salts of-a-sulfonated fatty acid esters of the present invention are known compounds and are described in U.S. Patent 3,223,645, issued December 14, 1965 to Kalberg.

(2) Anionic organic detergents which are salts of 2 - acyloxy - alkane - 1 - sulfonic acids.

These salts have the formula:

where R, is alkyl of9 to 23 carbon atoms; R2 is alkyl of I to 8 carbon atoms: and M is a salt-forming moiety as hereinbefore described.

Specific examples of uX - acyloxy alkane - I - sulfonates, or alternatively, 2 acyloxy - alkane - I - sulfonates, utilizable herein to provide superior curd dispersion include the sodium salt of 2 - acetoxy - tridecane - 1 - sulfonic acid; the potassium salt of 2 - propionyloxy - tetradecane - 1 sulfonic acid; the lithium salt of 2butanoyloxy - tetradecane - 1 - sulfonic acid; the sodium salt of 2 - pentanoyloxy pentadecane - 1 - sulfonic acid; the ammonium salt of 2 - hexanoyloxy - hexadecane - 1 - sulfonic acid; the sodium salt of 2 - acetoxy - hexadecane - 1 - sulfonic acid; the dimethylammonium salt of 2 heptanoyloxy - tridecane - I - sulfonic acid; the potassium salt of 2 - octanoyloxy - tetradecane - I - sulfonic acid; the dimethylpiperidinium salt of 2 - nonanoyloxy - tetradecane - I - sulfonic acid; the sodium salt of 2 - acetoxy - heptadecane 1 - sulfonic acid; the lithium salt of 2 - acetoxy - octadecane - I - sulfonic acid; the dimethylamine salt of 2 - acetoxy octadecane - 1 - sulfonic acid; the potassium salt of 2- acetoxy - nonadecane - 1 - sulfonic acid; the sodium salt of 2- acetocy - eicosane - 1 - sulfonic acid; the sodium salt of 2 - propionyloxy docosane - 1 - sulfonic acid; and isomers thereof.

Preferred ,B- - acyloxy - alkane - I - sulfonate salts herein are the alkali metal salts of p - acetoxy - alkane - I - sulfonic acids corresponding to the above formula wherein R, is an alkyl moiety of about 12 to about 16 carbon atoms, these salts being preferred from the standpoint of their excellent curd-dispersing properties and ready availability.

Typical examples of the above described p - acetoxy alkanesulfonates are described in the literature: Belgian Pat. 650,323 issued July 9, 1963, discloses the preparation of certain 2- acyloxy alkanesulfonic acids.

Similarly, U.S. Pats. 2,094,451 issued Sept.

28, 1937, to Guenther et al. and 2,086,215 issued July 6, 1937 to De Groote disclose certain salts of p - acetoxy alkanesulfonic acids.

(3) Anionic organic detergents which are alkyl ether sulfates.

These materials have the formula RO(C2H4O)XSO3M wherein R is an alkyl or alkenyl moiety of 10 to 20 carbon atoms, x is 1 to 30, and M is a salt-forming cation as defined hereinbefore.

The alkyl ether sulfates useful in the present invention as curd dispersants are condensation products of ethylene oxide and monohydric alcohols having 10 to 20 carbon atoms. Preferably, R has 14 to 18 carbon atoms. The alcohols can be derived from fats, e.g. coconut oil or tallow, or can by synthetic. Lauryl alcohol and straight chain alcohols derived from tallow are preferred herein. Such alcohols are reacted with I to 30, and especially 3 or 6, molar proportions of ethylene oxide and the resulting mixture of molecular species, having, for example, an average of 3 or 6 moles of ethylene oxide per mole of alcohol, is sulfated and neutralized.

Specific examples of alkyl ether sulfates of the present invention are sodium coconut alkyl ethylene glycol ether sulfate; lithium tallow alkyl trialkylene glycol ether sulfate; sodium tallow alkyl hexaoxyethylene sulfate; and ammonium tetradecyl octaoxyethylene sulfate.

Preferred herein for reasons of excellent curd-dispersing properties and ready availability are the alkali metal coconutand tallow-alkyl oxyethylene ether sulfates having an average of 3 to 10 oxyethylene moieties. The alkyl ether sulfates of the present invention are known compounds and are described in U.S. Pat. 3,322,876 to Walker (July 25, 1967).

(4) Anionic organic detergents which are olefin sulfonates having 12 to 24 carbon atoms.

The term "olefin sulfonates" is used herein to mean compounds which can be produced by the sulfonation of a-olefins by means of uncomplexed sulfur trioxide, followed by neutralization of the acid reaction mixture using conditions such that any sulfones which have been formed in the reaction are -hydrolyzed to give the corresponding hydroxy-alkanesulfonates.

The sulfur trioxide may be liquid or gaseous, and is usually, but not necessarily, diluted by inert diluents, for example by liquid SO2, chlorinated hydrocarbon, etc., when used in the liquid form, or by air, nitrogen, gaseous SO2, etc., when used in the gaseous form.

The a-olefins from which the olefin sulfates are derived are mono-olefins having 12 to 24 carbon atoms, preferably 14 to 16 carbon atoms. Preferably, they are straight chain olefins. Examples of suitable 1 - olefins include I - dodecene; 1 - tetradecene; I - hexadecene; I - octadecene; 1 - eicosene and I - tetracosene.

In addition to the true alkene sulfonates and a proportion of hydroxyalkanesulfonates, the olefin sulfonates can contain minor amounts of other materials, such as alkene disulfonates, depending upon the reaction conditions, proportions of reactants, the nature of the starting olefins and impurities in the olefin stock and side reactions during the sulfonation process.

A preferred group of curd-dispersing agents for the present purpose comprises those olefin sulfonates which are described completely in U.S. Pat. 3,332,880 issued July 25, 1967, to Kessler et al.

(5) Ampholytic synthetic detergents which are derivatives of aliphatic secondary and tertiary amines in which the aliphatic group can be straight chain or branched and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate.

These detergents have the formula

wherein R, is alkyl of 8 to 18 carbon atoms, R2 is alkyl of 1 to 3 carbon atoms or is hydrogen, R3 is alkylene of 1 to 4 carbon atoms, Z is carboxy, sulfonate, sulfate, phosphate or phosphonate and M is a saltforming cation, as hereinbefore described.

Examples of compounds falling within this definition are sodium 3- dodecylamino propionate; sodium 3 - dodecylaminopropane sulfonate; n - alkyltaurines such as the ones prepared by reacting dodecylamine with sodium isethionate according to the teaching of U.S. Pat. 2,658,072; sodium salts of N-higher alkyl aspartic acids such as those produced according to the teaching of U.S. Pat. 2,438,091; and the products sold under the registered Trade Mark "Miranol" and described in U.S. Pat. 2,528,378.

(6) Zwitterionic synthetic detergents which are derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds, in which the aliphatic groups can be straight chain or branched, and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. A general formula for these compounds is:

wherein Rl is an alkyl, alkenyl, hydroxyalkyl or alkylbenzyl group containing from 8 to 24 carbon atoms and having from 0 to 10 ethylene oxide moieties and from 0 to I Rlyceryl moiety; Y is selected from the group consisting of nitrogen, phosphorus, and sulfur atoms; R2 is an alkyl or monohydroxy alkyl group containing 1 to 3 carbon atoms; x is I when Y is a sulfur atom and 2 when Y is a nitrogen or phosphorus atom, R3 is an alkylene or hydroxy alkylene group of from I to 4 carbon atoms and Z is a member selected from the group consisting of carboxylate, sulfonate, sulfate, phosphonate, and phosphate groups.

Examples include: 4- [N,N - di(2 - hydroxyethyl) - N octadecyl - ammoniol - butane - I - carboxylate; 5 - IS - 3 - hydroxypropyl - S - hexadecylsulfoniol - 3 - hydroxypentane - 1 sulfate; 3 - [P,P - diethyl - P - 3,6,9 - trioxa tetracosanephosphoniol - 2- hydroxypropane - 1 - phosphate; 3 - 1N,N - dipropyl - N - 3 - dodecoxy 2 - hydroxypropylammonio] - propane - phosphonate; 3 - N,N - dimethyl - N - hexadecyl- ammonio)propane - I - sulfonate; 3 - (N,N - dimethyl - N - hexadecyl ammonio)- 2- hydroxypropane - 1 - sulfonate 4 - lN,N' - di(2 - hydroxyethyl) - N - (2 hydroxydodecyl)ammoniol - butane - 1 - carboxylate; 3 - (S -ethyl - S - (3 - dodecoxy - 2 hydroxypropyl)sulfonio] - propane - 1 - phosphate; 3 - [P,P - dimethyl - P - dodecylphos phoniol - propane - 1 - phosphonate; S - [N,N - di(3 - hydroxypropyl) - N hexadecyl- ammoniol - 2- hydroxypentane - 1 - sulfate; 3- (dodecylbenzyldimethylammonio)propane - 1 - sulfonate; and 2 - (dodecylbenzyldimethylammonio)- ethane - 1 - sulphate.

Examples of compounds falling within this definition also include 3 - (N,N - dimethyl - N - hexadecyl - ammonio)propane - I - sulfonate and 3 - (N.N - di methyl - N - hexadecyl - ammonio) - 2 hydroxypropane - I - sulfonate whichare especially preferred herein for their availability and curd dispersant characteristics. Some of the compounds of this type as well as their use as dispersing agents are more fully described in U.S.

Patents 2,699,991 and 3,660,470.

(7) Organic carboxylic acid am ides. These may be employed in amounts not exceeding /n by weight of the soap/scum dispersant granules.

Such amide compounds include those aliphatic amides of the general formula:

wherein R is hydrogen, alkyl or alkylol and R' and R" are hydrogen, alkyl, alkylol or alkylene joined through an oxygen atom, the total number of carbon atoms in R, R' and R" being from 9 to 25.

Amides of this general type which are of special utility are those aliphatic carboxylic acid alkanol amides of the formula:

in which RCO is the acyl group of a soapforming carboxvlic acid having from 10 to 18 carbon atoms, R' and R" are each selected from: hydrogen, alkyl and alkylol substituents, and R"' is an alkyol substitutent, the total number of carbon atoms in R', R" and R"' being from 1 to 7.

Some specific amides coming within the scope of the invention are: lauric ethanolamide: stearic ethanolamide; and lauric isopropanol amide.

Especially preferred is tallow acyl monoethanolamide.

Such acids, their preparation, and their use as dispersing agents are discussed more fully in U.S. Patent 2,527,076.

Of all the above-described types of curddispersing agents, the compounds preferred for use in the granular particles of the instant composition include the sodium salt of the methyl ester of cr-sulfonated tallow fatty acid, the sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 3 ethylene oxide groups per mole; the sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 6 ethylene oxide groups per mole; sodium - acetoxyhexadecane - 1 - sulfonate; sodium - acetoxy tridecane - 1 sulfonate; the sodium salt of sulfonated 1 hexadecene; dimethyldodecylphosphine oxide; sodium hexadecylmethylaminopropionate; 3(N,N - dimethyl - N - alkylammonio)- propane - 1 - sulfonate and 3(N,N - dimethyl - N - alkylammonio) 2 - hydroxypropane - 1 - sulfonate wherein in each propane sulfonate compound the alkyl group averages approximately 14.8 carbon atoms in length; 3(N,N - dimethyl N - hexadecylammonio)propane - I sulfonate; 3(N,N - dimethyl - N - hexadecyl - ammonio) - 2 - hydroxypropane - - sulfonate; 3 - (N - dodecylbenzene - N,N - dimethyl ammonio) - propane - 1 sulfonate.

Highly preferred curd-dispersing agents herein are the sodium salt of ethoxylated tallow alkyl sulfate averaging approximately 3 ethylene oxide groups per mole, the sodium salt of ethoxylated tallow alkyl sulfate averaging approximately 6 ethylene oxide groups per mole, and tallow and coconut acyl monoethanolamides.

Besides the above-described soap and curd-dispersing components, the granular particles of the instant compositions can contain a wide variety of optional components generally found in conventional fabric laundering formulations. Such optional components include, for example, conventional anionic or nonionic surfactants which are not particularly useful as curd dispersants and alkaline builder salts. Such non-curd dispersing surfactants are those having a percentage value in the above-described lime soap peptizing test greater than 390/, and include the sodium salts of linear alkyl benzene sulphonic acids wherein the alkyl group averages 10 to 18 carbon atoms in length, and sodium tallow alkyl sulfate.

When employed, such conventional noncurd-dispersing surfactants generally comprise from 1% to 30% by weight of the granular particle.

Typical alkaline builders include sodium tripolyphosphate, sodium citrate, sodium nitrilotriacetate, sodium carbonate and sodium mellitate. When employed, such conventional builders generally comprise from 1% to 30 /,, by weight of the granular particles.

Other optional granule components include the various soil-suspending agents such as carboxymethylcellulose, corrosion inhibitors, dyes, fillers such as sodium sulfate and silica, optical brighteners, bleaches such as sodium perborate, suds boosters, suds depressants, germicides, antitarnishing agents, pH adjusting agents such as sodium silicate, and enzymes, well known in the art for use in detergent compositions. Bound water can also be present in said compositions.

The soap-based granules herein can be prepared in standard fashion, e.g., by blending the soap, curd dispersant and optional ingredients of the granules in a crutcher, and subsequently blowing the mix in standard spray-drying equipment.

Clay Compounds The present compositions contain, as an essential ingredient, particulate smectitetype clay materials which provide fabric softening concurrently with fabric cleansing. These smectite clays are present in the detergent compositions at the abovementioned concentrations from 4% to 25%, preferably from 5% to 150/,, by weight, of the total composition. As mentioned above, the weight ratio of the granular particles to the clay is from 20:1 to 3:1 by weight.

The clay minerals used to provide the softening properties of the instant compositions can be described as impalpable, expandable, three-layer clays, i.e., alumino-silicates and magnesium silicates, having an ion exchange capacity of at least 50 meg/100 g. of clay. The term "impalpable" as used to describe the clays indicates that the clay particles are of a size such that they cannot be perceived tactilely.

Such particle sizes are usually within the range below 50 microns. The term "expandable" as used to describe clays relates to the ability of the layered clay structure to be swollen, or expanded, on contact with water. The three-layer expandable clays used herein are those materials classified geologically as smectites.

There are two distinct classes of smectitetype clays. In the first, aluminum oxide is present in the silicate crystal lattice; in the second class of smectites, magnesium oxide is present in the silicate crystal lattice. The general formulae of these smectites are Al2 (Si2Os)2(OH)2 and Mg3(Si2Os)2(OH)2, for the aluminum and magnesium oxide type clay, respectively. It is to be recognized that the range of the water of hydration in the above formulas can vary with the processing to which the clay has been subjected. This is immaterial to the use of the smectite clays in the present invention in that the expandable characteristics of the hydrated clays are dictated by the silicate lattice structure.

Furthermore, atom substitution by iron and magnesium can occur within the crystal lattice of the smectites, while metal cations such as Na+, Ca++, as well as H+, can be copresent in the water of hydration to provide electrical neutrality. Except as noted hereinafter, such cation substitutions are immaterial to the use of the clay herein since the desirable physical properties of the clays are not substantially altered thereby.

The three-layer, expandable aluminosilicates useful herein are further characterized by a dioctahedral crystal lattice, whereas the expandable three-layer magnesium silicates have a tri-octahedral crystal lattice.

As noted hereinabove, the clays employed in the instant invention contain cationic counterions, e.g. protons, sodium ions, potassium ions, calcium ion or magnesium ion. It is customary to distinguish between clays on the basis of one cation predominantly or exclusively absorbed. For example, a sodium clay is one in which the absorbed cation is predominantly sodium. Such absorbed cations can become involved in exchange reactions with cations present in aqueous solutions. A typical exchange reaction involving a smectite-type clay is expressed by the following equation: smectite clay (Na)+NH4OHr smectite clay (NH,)+NaOH Since in the foregoing equilibrium reaction, one equivalent weight of ammonium ion replaces an equivalent weight of sodium, it is customary to measure clay cation exchange capacity (sometimes termed "base exchange capacity") in terms of milliequivalents per 100 g. of clay (me ion followed by titration, or a methylene blue procedure, all as fully set forth in Grimshaw, The Chemistry and Physics of Clays, Interscience Publishers, Inc. pp.

264-265 (1971). The cation exchange capacity of a clay mineral relates to such factors as the expandable properties of the clay, the charge of the clay, which, in turn, is determined at least in part by the lattice structure, and the like. The ion exchange capacity of clays varies widely in the range usually from 2 meq/100 g. for kaolinites to 150 meq/100 R., and greater, for certain clays of the montmorillonite variety. Illite clays have an ion exchange capacity somewhere in the lower portion of the range, i.e., around 26 meq/100 g. for an average illite clay.

It has been determined that illite and kaolinate clays, with their relatively low ion exchange capacities, are not useful in the instant compositions. Indeed, such illite and kaolinite clays constitute a major component of clay soils and, are, in fact removed from fabric surfaces by means of the instant compositions. However, smectites, such as nontronite, having an ion exchange capacity of approximately 50 meq/l00 g., saponite, which has an ion exchange capacity of around 70 meq/100 g., and montmorillonite, which has an ion exchange capacity greater than 70 meq/100 g., have been found to be useful because such smectites, if attached to the granule surface, increase composition solubility while, once added to laundering liquor, they deposit on the fabrics to provide softening.

Accordingly, clay minerals useful herein can be characterized as impalpable, expandable, three-layer smectite-type clays having an ion exchange capacity of at least 50 meq/100 g.

The smectite clays used in the compositions herein are all commercially available. Such clays include, for example, montmorillonite, volchonskoite, nontronite, hectorite, saponite, and sauconite.

The clays herein are available under commercial names such as "fooler clay" (clay found in a relatively thin vein above the main bentonite or montmorillonite veins in the Black Hills) and various trade names such as Thixogel No. I and Gelwhite GP from Georgia Kaolin Co., Elizabeth, New Jersey, Volclay BC and Volclay No. 325 (Volclay being a registered Trade Mark), from American Colloid Co., Skokie, Illinois; Black Hills Bentonite BH 450, from International Minerals and Chemicals; and Veegum Pro and Veegum F (Veegum being a registered Trade Mark), from R. T. Vanderbilt. It is to be recognized that such smectite-type minerals obtained under the foregoing commercial and tradenames can comprise mixtures of the various discrete mineral entities. Such mixtures of the smectite minerals are suitable for use herein.

While any of the impalpable smectitetype clays having a cation exchange capacity of at least 50 meq/100 g. are useful herein, certain clays are preferred. For example, Gelwhite GP and "fooler clay" are extremely white forms of smectite clays and are therefore preferred when formulating white, granular compositions.

Volclay BC, which is a smectite-type clay mineral containing at least 3% of iron (expressed as Foe203) in the crystal lattice, and which has a very high ion exchange capacity, is one of the most efficient and effective clays for use in laundry compositions and is preferred from the standpoint of fabric softening performance.

Likewise, Thixogel No. I, is a preferred clay herein from the standpoint of throughthe-wash fabric softening performance. On the other hand, certain smectite clays, such as those marketed under the name "bentonite", are sufficiently contaminated by other silicate minerals that their ion exchange capacity falls below the requisite range, and such clays are of no use in the instant compositions.

Appropriate clay minerals for use herein can be selected by virtue of the fact that smectites exhibit a true 14A x-ray diffraction pattern. This characteristic pattern, together with exchange capacity measurements performed in the manner noted above, provides a basis for selecting suitable impalpable smectite-type clay minerals for use in the granular detergent compositions disclosed herein.

Composition Preparation The compositions herein are formulated by separately preparing the clay agglomerates and the granules comprising the soap, curd dispersant, and any of the optional ingredients mentioned hereinabove, and then dry mixing the clay agglomerates with the soap-based granules.

The clay agglomerates and their preparation are described as follows.

The weight of agglomerating agent to clay is preferably from I to 40 per cent. Most suitable agglomerating agents are liquids at temperatures below about 60"C. Optionally, the agglomerating agent can have suspended therein some of the clay for the compositions.

When none of the clay is dispersed in the agglomerating agent before being sprayed, suitable agglomerating agents include dilute (i.e. not over 75% saturated) aqueous solutions of electrolytes; water; and solution of organic adhesives and nonionic surfactants.

When some of the clay is to be dispersed in the agglomerating agent and the dispersion sprayed onto the remainder of the clay, the same agglomerating agents can be used, but generally the electrolyte solutions are preferred. The use of water by itself is preferred when dilute clay dispersions are used or when certain clays, which do not form too viscous or gelatinous dispersions, are employed. Clays which give thick, or gelatinous dispersions in water can be made into more concentrated, but still sprayable, dispersions in electrolyte solution as described above.

Suitable electrolytes include water soluble phosphates, tripolyphosphates and acid and neutral (e.g. tetrasodium or disodium) pyrophosphates, carbonates, sulphates, chlorides, borates, and silicates and mixtures thereof. The solution are generally less than about 75% saturated, and are usually quite dilute. Thus a very effective solution contains from 3 to 20%, especially approximately 15%, of disodium pyrophosphate, or a 2:1 by weight mixture of disodium pyrophosphate and sodium chloride, especially approximately 5% and approximately 2+% of these salts respectively. Sodium silicate solution, of ratio SiO2:Na2O from 1:1 to 3.6:1 by weight, and of up to approximately 50% solids concentration, for instance as commonly marketed, may be employed.

Organic adhesives which can be used include dextrin, gelatine, carboxymethylcellulose, starch, carboxymethyl starch, and alkyl and hydroxy alkyl substituted cellulose and starches. These are usually employed in aqueous solutions containing up to 40% by weight of the organic material. A preferred material is dextrin employed at appromimately 30 /" by weight in aqueous solution.

All manner of common ethoxylated nonionic surfactants can also be used for this purpose. Nonionic surfactants produced by the condensation of an alkylene oxide moiety (hydrophilic in nature) with an organic hydro-phobic compound which is usually aliphatic or alkyl aromatic in nature can be used. The length of the hydrophilic or polyoxyalkylene moiety which is condensed with any particular hydrophobic compound can be readily adjusted to yield colorless, liquid or liquifiable, water dispersable, organic, nonionic surfactants which are useful adhesion promoters herein.

Examples of nonionic surfactants which can be used as the adhesion-promoting materials herein include: (1) The polyethylene oxide condensates of alkyl phenols. These compounds include the condensation products of alkyl phenols having an alkyl group containing from 6 to 12 carbon atoms, in either a straight chain or branched chain configuration, with ethylene oxide, said ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol.

The alkyl substituent in such compound can be derived, for example, from polymerized propylene, diisobutylene, octene, or nonene. Examples of compound of this type include nonyl phenol condensed with approximately 9.5 moles of ethylene oxide per mole of nonyl phenol, dodecyl phenol condensed with approximately 12 moles of ethylene oxide per mole of phenol, dinonyl phenol condensed with approximately 15 moles of ethylene oxide per mole of phenol, diisooctylphenol condensed with approximately 15 moles of ethylene oxide per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-610, marketed by the GAF Corporation; and Triton (registered Trade Mark) X-45, X-114, X-100 and X-102, all marketed by the Rohm and Haas Company.

(2) The condensation products of aliphatic alcohols with ethylene oxide. The alkyl chain of the aliphatic alcohol can either be straight or branched and usually contains from 8 to 22 carbon atoms.

Examples of such ethoxylated alcohols include the condensation product of approximately 6 moles of ethylene oxide with 1 mole of tridecanol, m ristyl alcohol condensed with approximately 10 moles of ethylene oxide per mole of myristyl alcohol, the condensation product of ethylene oxide with coconut fatty alcohol wherein the coconut alcohol is a mixture of fatty alcohols with alkyl chains varying from 10 to 14 carbon atoms and wherein the condensate contains approximately 6 moles of ethylene oxide per mole of alcohol, and the condensation product of approximately 9 moles of ethylene oxide with the abovedescribed coconut alcohol. Examples of commercially available nonionic surfactants of this type include Tergitol (registered Trade Mark) 15--SS-9 marketed by the Union Carbide Corporation, Neodol 236.5 marketed by the Shell Chemical Company, and Kyro (registered Trade Mark) EOB marketed by The Procter & Gamble Company.

(3) The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of these compounds usually has a molecular weight of from 1500 to 1800. The addition of polyoxyethylene moieties 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 the polyoxyethylene content is approximately 50 /" of the total weight of the condensation product.

Examples of compounds of this type include certain of the commercially available Pluronic (registered Trade Mark) surfactant marketed by the Wyandotte Chemicals Corporation.

(4) The condensation products of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. The hydrophobic base of these products consists of the reaction product of ethylenediamine and excess propylene oxide, said base usually having a molecular weight of from 2500 to 3000. This base is condensed with ethylene oxide to the extent that the condensation product contains usually from 40% to 80 /n by weight or polyoxyethylene and has a molecular weight usually of from 5,000 to 11,000.

An important aspect of the present invention is that the smectite clay used in preparing the agglomerates is present in "impalpable" particulate form. By "impalpable" clay, as stated earlier, we mean clay whose individual particles are of a size such that they cannot be perceived tactilely.,and such particles have an average size usually within the range below 50 microns, preferably within the range of from 5 microns to 25 microns. In the agglomerate, the individual grains of clay are loosely bound together by physical adhesive forces, but the "impalpable" nature of the ultimate clay particles is retained and the agglomerates are readily broken down to their intrinsic particulate constituents under agitation forces applied during a washing process.

The size of the clay agglomerates is also an important consideration in the process of the invention, and the overall aim is to prepare agglomerates having a particulate size such that, preferably at least 50 wit.%, and more preferably, at least 65 wit.% pass through a 22 mesh sieve, with preferably at least 95 wt.% and more preferably at least 98 wit.% passing through a 12 mesh sieve, and with preferably no more than 10 wit.%, more preferably no more than 5 wit.% passing through a 100 mesh sieve (all British Standard mesh sizes). These limits are chosen so as to minimize the content of "fines" and "oversize" in the particle distribution, as it has been found that large amounts of "fines" deleteriously affect the free-flowing properties of the agglomerates; large amounts of "oversize", on the other hand, have been found to give the final product a. somewhat coarse and irregular appearance.

Another important consideration in the preparation of the clay agglomerates, when the agglomerating agent is aqueous in character, is the moisture content of the agglomerate, which usually should lie in the range from 15 to 40%, preferably from 20 to 35 /n and more preferably from 23 to 30'/ by weight of the agglomerate. The moisture content is controlled within this range in order to optimize two granule characteristic its flow characteristics, which tend to deteriorate towards higher moisture content, and its average particle size, which tend to diminish towards lower moisture content. The optimum moisture content has been found to be in the region of 28%.

The agglomeration process itself may be performed using any of the techniques and apparatus which are conventional in the art, e.R. in a fluidized bed, rotating drum, Schugi agglomerator, falling curtain agglomerator or rotating pan agglomerator. The optimum operation conditions required to give the average granule size and moisture content specified above can be found by trial adjustment of process parameters such as the liquid spray-on rate and droplet size, and the rate of removal of agglomerates from the apparatus.

The clay can be co-agglomerated with other fine or potentially dusty components of the composition such as enzymes, optical brighteners. whitening or colouring substances, e.g. titanium dioxide or the pigments. Thereafter, the clay agglomerates are dry-mixed with soap granules comprising soap and curd-dispersing agent, and with other components, if any, of the final product.

The invention is illustrated by the following examples.

Example 1 4.76 parts of Thixogel + (marketed by Georgia Kaolin Co., Elizabeth, New Jersey, U.S.A.) were sprayed with 0.93 parts of a 15 by weight aqueous solution of disodium pyrophosphate in a rotating pan granulator operating to give an average granule moisture content of approximately 28 /n by weight and a granule size such that at least 70% of the agglomerates passed throueh a 22 mesh sieve.

Thereafter, the clay was dry mixed with 67 parts of a spray dried soap composition containing by weight on the same basis 43 parts soap (80/20 tallow/coconut soap). 2.4 parts tallow monoethanolamide, 11 parts sodium silicate, 10 parts moisture and 3 parts minor components. The resulting granular mixture was then dry-mixed with 15 parts sodium perborate and 10 parts sodium tripolyphosphate.

Softness Measurements Swatches of terry towelling (6 per test) were washed in 0.4% by weight solutions of the test products in a Tergitometer. The solutions were prepared in tap water (172 ppm hardness as CaCO2), and the washing conditions were two washes of 2 minutes duration at 500 C, with a cloth to liquor ratio of 1:10, followed by rinsing and drying in still air. The washed and dried swatches were compared by a panel of four judges by a paired comparison technique using a 9 point Scheffe scale. Differences were recoded in panel score units (psu), positive being preferred. and the least significant difference (LSD) at 95 /n confidence was also calculated.

Example Standard LSD softness +0.95 -0.95 0.65 The composition of the Example was additionally found to have greatly reduced dust-forming characteristics compared with a composition comprising dry-mixed unagglomerated clay.

Example 2 A soap-based laundry granule is prepared having the following composition: Component Wt. /,} Sodium soap"' 42.6 Potassium soap'1 11.2 TAE3S''' 10.7 C,,,LAS'3L 8.8 Sodium silicate 8.9 Sodium sulfate 11.9 Brightener (stilbene type) 0.57 Perfume 0.17 Water 3.4 Miscellaneous Balance (I) Soap mixtures comprising 90% tallow and 10% coconut soaps (2) Sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 3 ethylene oxide units per molecule.

(3) Sodium salt of linear alkyl benzene sulfonate having an average alkyl chain length of approximately 12 carbon atoms.

The foregoing ingredients are mixed in a crutcher and spray-dried to provide a granular, soap-based composition.

Eighty-eight and four-tenths parts by weight of the soap-based granules prepared above are admixed with 11.6 parts by weight of agglomerated thixogel prepared as described in Example I.

The resulting composition is a stable laundry detergent formulation providing excellent fabric laundering solubility and fabric softening characteristics when added to laundering liquor to the extent of approximately 0.120/, by weight.

Substantially similar results are obtained when the ethoxylated tallow alkyl sulfate curd dispersing agent of Example 2 is replaced with equivalent amounts of the sodium salt of the methyl ester of a sulfonated tallow fatty acid; the sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 6 ethylene oxide groups per mole; sodium P- acetoxy - hexadecane - I - sulfonate; sodium p acetoxy tridecane - I - sulfonate; the sodium salt of sulfonated 1 - hexadecene; dimethyldodecylphosphine oxide; sodium hexadecylmethylaminopropionate; 3(N,N dimethyl - N - alkylammonio) - propane I - sulfonate and 3(N,N - dimethyl - N alkylammonio) - 2 - hydroxypropane - I - sulfonate wherein both compounds the alkyl group averages 14.8 carbon atoms in length; 3(N,N - dimethyl - N - hexadecyl ammonio) - propane - 1 - sulfonate; 3(N,N - dimethyl - N - hexadecylammonio)- 2 - hydroxypropane - 1 - sulfonate; 3 - (N - dodecylbenzyl - N,N dimethyl - ammonio)- propane - 1 - sulfonate.

Substantially similar results are obtained, when the Thixogel *1 clay of Examples 1 and 2 is replaced with an equivalent amount of "fooler clay", Gelwhite GP, Volclay *325, Black Hills Bentonite BH 450, Veegum Pro or Veegum F, and when the sodium linear alkyl benzene sulfonate noncurd-dispersing surfactant of Example 2 is replaced with an equivalent amount of sodium tallow alkyl sulfate.

Substantially similar results are obtained when the aqueous disodium pyrophosphate agglomerating agent of Examples I and 2 is replaced by a 2:1 aqueous mixture of disodium pyrophosphate and sodium chloride; coconut alcohol ethoxylate containing 6 ethylene oxide units per mole; tallow alcohol ethoxylate containing I 1 ethylene oxide units per mole; water; 30 Nn aqueous dextrin solution; 15% aqueous gelatine solution; or a 150/n aqueous solution of carboxymethylcellulose.

WHAT WE CLAIM IS: I. A process for making a laundry detergent composition comprising: (A) granular particles which comprise (i) from 30 /,, to 80 /n by weight of the granular particles of a soap compound; and (ii) from I 1% to 30 /" by weight of the granular particles of a curd-dispersing agent; and (B) from 4% to 25% by weight of the composition of a smectite-type clay having an ion exchange capacity of at least 50 meq/100 g of clay, the composition having a weight ratio of granular particles to smectite clay of from 20:1 to 3:1, in which process a moving mass of impalpable smectite clay particles is sprayed with a liquid agglomerating agent selected from water, aqueous electrolyte solutions, nonionic surfactants and aqueous solutions of organic

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   conditions were two washes of 2 minutes duration at 500 C, with a cloth to liquor ratio of 1:10, followed by rinsing and drying in still air. The washed and dried swatches were compared by a panel of four judges by a paired comparison technique using a 9 point Scheffe scale. Differences were recoded in panel score units (psu), positive being preferred. and the least significant difference (LSD) at 95 /n confidence was also calculated.

   Example Standard LSD softness +0.95 -0.95 0.65 The composition of the Example was additionally found to have greatly reduced dust-forming characteristics compared with a composition comprising dry-mixed unagglomerated clay.

   Example 2 A soap-based laundry granule is prepared having the following composition: Component Wt. /,} Sodium soap"' 42.6 Potassium soap'1 11.2 TAE3S''' 10.7 C,,,LAS'3L 8.8 Sodium silicate 8.9 Sodium sulfate 11.9 Brightener (stilbene type) 0.57 Perfume 0.17 Water 3.4 Miscellaneous Balance (I) Soap mixtures comprising 90% tallow and 10% coconut soaps (2) Sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 3 ethylene oxide units per molecule.

   (3) Sodium salt of linear alkyl benzene sulfonate having an average alkyl chain length of approximately 12 carbon atoms.

   The foregoing ingredients are mixed in a crutcher and spray-dried to provide a granular, soap-based composition.

   Eighty-eight and four-tenths parts by weight of the soap-based granules prepared above are admixed with 11.6 parts by weight of agglomerated thixogel prepared as described in Example I.

   The resulting composition is a stable laundry detergent formulation providing excellent fabric laundering solubility and fabric softening characteristics when added to laundering liquor to the extent of approximately 0.120/, by weight.

   Substantially similar results are obtained when the ethoxylated tallow alkyl sulfate curd dispersing agent of Example 2 is replaced with equivalent amounts of the sodium salt of the methyl ester of a sulfonated tallow fatty acid; the sodium salt of ethoxylated tallow alkyl sulfate having an average of approximately 6 ethylene oxide groups per mole; sodium P- acetoxy - hexadecane - I - sulfonate; sodium p acetoxy tridecane - I - sulfonate; the sodium salt of sulfonated 1 - hexadecene; dimethyldodecylphosphine oxide; sodium hexadecylmethylaminopropionate; 3(N,N dimethyl - N - alkylammonio) - propane I - sulfonate and 3(N,N - dimethyl - N alkylammonio) - 2 - hydroxypropane - I - sulfonate wherein both compounds the alkyl group averages 14.8 carbon atoms in length; 3(N,N - dimethyl - N - hexadecyl ammonio) - propane - 1 - sulfonate; 3(N,N - dimethyl - N - hexadecylammonio)- 2 - hydroxypropane - 1 - sulfonate; 3 - (N - dodecylbenzyl - N,N dimethyl - ammonio)- propane - 1 - sulfonate.

   Substantially similar results are obtained, when the Thixogel *1 clay of Examples 1 and 2 is replaced with an equivalent amount of "fooler clay", Gelwhite GP, Volclay *325, Black Hills Bentonite BH 450, Veegum Pro or Veegum F, and when the sodium linear alkyl benzene sulfonate noncurd-dispersing surfactant of Example 2 is replaced with an equivalent amount of sodium tallow alkyl sulfate.

   Substantially similar results are obtained when the aqueous disodium pyrophosphate agglomerating agent of Examples I and 2 is replaced by a 2:1 aqueous mixture of disodium pyrophosphate and sodium chloride; coconut alcohol ethoxylate containing 6 ethylene oxide units per mole; tallow alcohol ethoxylate containing I 1 ethylene oxide units per mole; water; 30 Nn aqueous dextrin solution; 15% aqueous gelatine solution; or a 150/n aqueous solution of carboxymethylcellulose.

   WHAT WE CLAIM IS: I. A process for making a laundry detergent composition comprising: (A) granular particles which comprise (i) from 30 /,, to 80 /n by weight of the granular particles of a soap compound; and (ii) from I 1% to 30 /" by weight of the granular particles of a curd-dispersing agent; and (B) from 4% to 25% by weight of the composition of a smectite-type clay having an ion exchange capacity of at least 50 meq/100 g of clay, the composition having a weight ratio of granular particles to smectite clay of from 20:1 to 3:1, in which process a moving mass of impalpable smectite clay particles is sprayed with a liquid agglomerating agent selected from water, aqueous electrolyte solutions, nonionic surfactants and aqueous solutions of organic

   adhesives, to form free flowing clay agglomerates and thereafter said agglomerates are dry mixed with said granular particles comprising soap and curd-dispersing agent and with other particulate components, if any, of the composition.
2. 2. A process according to Claim I wherein the weight ratio of agglomerating agent to smectite clay in the agglomeration step is from I to 40 per cent.
3. 3. A process according to Claim I or 2 wherein the electrolyte is selected from neutral and acid pyrophosphate, tripolyphosphates, carbonates, silicates and sulphates, and chlorides.
4. 4. A process according to Claim 3 wherein the agglomerating agent is an aqueous solution containing from 3 to 20% by weight of disodium pyrophosphate or of a 2:1 by weight mixture of disodium pyrophosphate and sodium chloride.
5. 5. A process according to any one of Claims I to 4 wherein some of the clay is dispersed in the agglomerating agent so as to provide a sprayable dispersion and the dispersion is sprayed onto a moving mass of the remainder of the clay to form free.

   flowing agglomerates.
6. 6. A process according to Claim 5 wherein the dispersion of clay in the agglomerating agent contains up to 50 /n of clay by weight of the dispersion.
7. 7. A process according to any preceding Claim performed in a pan granulator, rotating drum, fluidized bed or a falling curtain agglomerator.
8. 8. A process according to any preceding Claim wherein the clay particles have an average particle size of less than 50 microns.
9. 9. A process according to any preceding Claim wherein the clay agglomerates have a size distribution such that at least 95 weight per cent of the agglomerates pass through a 12 mesh British Standard sieve and no more than 10 weight per cent of the agglomerates pass through a 100 mesh British Standard sieve.
10. 10. A process according to any preceding Claim in which the clay agglomerates have a moisture content in the range from 15 to 40 weight per cent.
11. 11. A process according to any preceding Claim wherein the clay particles have an average particle size in the range from 5 to 25 microns, and the clay agglomerates have a size distribution such that at least 50 weight per cent of the agglomerates pass through a 22 mesh British Standard sieve and no more than 5 weight per cent of the agglomerates pass through a 100 mesh British Standard sieve, the agglomerates having a moisture content in the range from 20 to 35 weight per cent.
12. 12. A laundry detergent composition prepared by the process of any of Claims I to 11.