Detergent compositions

Abstract

Granular, phosphate-free, storage-stable detergent compositions which are mixtures of anionic surfactant-containing, spray-dried granular particles and porous sodium silicate granular particles having a nonionic surfactant absorbed within the pores thereof.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of the application of Bonaparte, Golliday and Zeller, Ser. No. 298,143, filed Oct. 16, 1972 now abandoned.

Description

BACKGROUND OF THE INVENTION

The instant invention relates to granular laundry detergent compositions containing two distinct types of surfactant-containing granular particles. One particle type is of the conventional spray-dried variety and contains an anionic surfactant. The other particle comprises porous sodium silicate into the pores of which are absorbed particular types of nonionic surfactants.

Commercial synthetic detergent compositions have for years employed substantial amounts of inorganic phosphate salts as builder materials. Such phosphate builder materials serve to sequester or complex mineral ions commonly found in household tap water to prevent such ions from interfering with cleaning performance of the synthetic surfactant of such compositions. However, some recent studies have indicated that the phosphate class of builder materials may present an ecological problem because of the ability of these materials to act as a nutrient that promotes the growth of algae, thereby accelerating the biological aging (eutrophication) of natural water bodies. As a consequence of the possible harmful effects of the continued use of phosphate builder materials in substantial quantities, attempts have been made to materially reduce or eliminate the need for phosphate salts in commercial detergent compositions.

One method for compensating for the absence of mineral sequestering phosphate builder salts in detergent formulations has been to synthesize compositions containing surfactant systems which are particularly insensitive to mineral hardness in laundering solution. Such surfactant systems have, for example, included mineral-insensitive mixtures of anionic and nonionic surfactants. (See U.S. Pat. Nos. 2,543,744; 2,875,153; and 3,528,925 and the copending U.S. Pat. application of Collins, Ser. No. 222,363, filed Jan. 31, 1972.) However, since many common nonionic surfactants used in these systems are liquid at room temperature, many such formulations containing anionic-nonionic surfactant mixtures have been liquid in nature.

Attempts to achieve granular mixed anionic-nonionic detergent compositions (and the resulting commercial advantages of granular products) have not been entirely successful. Conventional spray drying of some nonionic surfactants may tend to produce air pollution problems which are difficult to overcome. To eliminate need for spray-drying, detergent compositions have also been formulated wherein liquid nonionic surfactant systems are absorbed or adsorbed into or onto solid porous material for use in granular products. (See U.S. Pat. Nos. 2,746,930; 3,285,859; 3,306,858; 3,408,300 and 3,674,700). Utilization of such "carrier" materials, however, has several disadvantages. Loading of such material to the surfactant levels necessary for highly effective mixed surfactant systems can result in "bleeding" of the absorbed or adsorbed material from its carrier during storage, thereby causing packaging, pouring and handling difficulties. Furthermore, in order to load the requisite levels of surfactant necessary for effective fabric laundering, inordinately large proportions of granular compositions of this type must consist of highly alkaline carrier material such as sodium silicate or sodium carbonate. Commercial detergent formulations containing excessive amounts of these highly alkaline materials may be disadvantageous from a safety (ingestion and eye irritation) standpoint.

Accordingly, it is an object of the present invention to provide phosphate-free, mixed anionic/nonionic surfactant-containing detergent compositions which are effective for fabric laundering in mineral-containing water.

It is a further object of the present invention to provide mixed surfactant detergent compositions in granular form having acceptable storage stability and pourability.

It is a further object of the present invention to provide mixed surfactant-containing detergent compositions containing acceptable levels of the mixed surfactant system without employing inordinately high levels of highly alkaline carrier materials.

It has been surprisingly discovered that by preparing granular detergent compositions containing both spray-dried anionic surfactant-containing granular particles and particles of a very particular type of sodium silicate having certain nonionic surfactants absorbed therein, detergent compositions can be formulated which accomplish the above objectives and which are superior in performance and physical characteristics to similar compositions presently known in the art.

SUMMARY OF THE INVENTION

The instant phosphate-free, granular detergent compositions consist essentially of from about 20% to about 70% by weight of the composition of anionic surfactant-containing spray-dried granules and from about 30% to about 80% by weight of the composition of nonionic surfactant-containing carrier granules. The spray-dried granules of the instant invention comprise from about 5% to about 40% by weight of the spray-dried granules of a conventional anionic surfactant. The carrier granules comprise a water-soluble, porous, amorphous sodium silicate carrier material having a weight ratio of Na.sub.2 O to SiO.sub.2 of from about 1:1 to 1:3.2 and a moisture content of from about 2% to about 12% by weight of the sodium silicate. The sodium silicate carrier material has absorbed within its pores a nonionic surfactant such that the weight ratio of absorbed nonionic surfactant to sodium silicate carrier material ranges from about 0.4:1 to 1.2:1. Within the detergent compositions of the instant invention, the concentration of anionic surfactant falls within the range of from about 3% to about 15% by weight of the total composition; the concentration of nonionic surfactant falls within the range of about 17% to 23% by weight and the weight ratio of nonionic surfactant to anionic surfactant within said composition ranges from about 8:1 to 1.13:1. The ratio of the average particle sizes of the spray-dried granules and nonionic surfactant-containing carrier granules varies between 0.5:1 and 2.0:1.

DETAILED DESCRIPTION OF THE INVENTION

The instant compositions consist essentially of two distinct types of detergent granules -- anionic-surfactant containing, spray-dried granules and nonionic-surfactant containing carrier granules. Each of these two granule types, as well as optional composition components and composition preparation, are described more fully as follows.

THE SPRAY-DRIED GRANULES

From about 20% to about 70%, preferably about 40% to about 55%, by weight of the total detergent compositions of the instant invention consists essentially of conventional spray-dried granules which contain a conventional anionic surfactant as well as optional conventional detergent composition additives such as fillers, brightener, perfumes, stabilizers, bleaching agents, enzymes, coloring agents, and moisture. The anionic surfactant comprises from about 5% to about 40%, preferably from about 15% to 25%, by weight of the spray-dried granules and is exemplified as follows.

Anionic Surfactants

Anionic synthetic detergents include water-soluble salts, particularly the alkali metal salts, of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 8 to about 22 carbon atoms and a moiety selected from the group consisting of sulfonic acid and sulfuric acid ester moieties. (Included in the term alkyl is the alkyl portion of higher acyl moieties.) Examples of this group of synthetic detergents are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C.sub.8 -C.sub.18 carbon atoms) produced by reducing the glycerides of tallow or coconut oil; sodium and potassium alkyl benzene sulfonates, in which the alkyl group contains from about 9 to about 20 carbon atoms in straight chain or branched-chain configuration, e.g. those of the type described in U.S. Pat. Nos. 2,220,099 and 2,477,383 (especially valuable are linear straight chain alkyl benzene sulfonates in which the average of the alkyl groups is about 11.8 carbon atoms and commonly abbreviated as C.sub.11.8 LAS); sodium alkyl glyceryl ether sulfonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; sodium and potassium salts of alkyl phenol ethylene oxide ether sulfates with about 1 to about 10 units of ethylene oxide per molecule and in which the alkyl groups contain from about 8 to about 12 carbon atoms.

Another class of suitable anionic organic detergents particularly useful in this invention includes salts of 2-acyloxyalkane-1-sulfonic acids. These salts have the formula ##EQU1## where R.sub.1 is alkyl of about 9 to about 23 carbon atoms (forming with the two carbon atoms an alkane group); R.sub.2 is alkyl of 1 to about 8 carbon atoms; and M is a water-soluble cation.

The water-soluble cation, M, in the hereinbefore described structural formula 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-, and trimethyl-ammonium cations and quaternary ammonium cations such as tetramethyl-ammonium and dimethyl piperidinium cations and those derived from alkylamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like.

Specific examples of beta-acyloxy-alkane-1-sulfonates, or alternatively 2-acyloxy-alkane-1-sulfonates, useful herein 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 2-butanoyloxy-tetradecane-1-sulfonic acid; the sodium salt of 2-pentanoyloxy-pentadecane-1-sulfonic acid; the sodium salt of 2-acetoxy-hexadecane-1-sulfonic acid; the potassium salt of 2-octanoyloxy-tetradecane-1-sulfonic acid; the sodium salt of 2-acetoxy-heptadecane-1-sulfonic acid; the lithium salt of 2-acetoxy-octadecane-1-sulfonic acid; the potassium salt of 2-acetoxy-nonadecane-1-sulfonic acid; the sodium salt of 2-acetoxy-uncosane-1-sulfonic acid; the sodium salt of 2-propionyloxy-docosane-1-sulfonic acid; the isomers thereof.

Preferred beta-acyloxy-alkane-1-sulfonate salts herein are the alkali metal salts of beta-acetoxy-alkane-1-sulfonic acids corresponding to the above formula wherein R.sub.1 is an alkyl of about 12 to about 16 carbon atoms, these salts being preferred from the standpoints of their excellent cleaning properties and ready availability.

Typical examples of the above described beta-acetoxy alkanesulfonates are described in the literature: Belgium Patent 650,323 issued July 9, 1963, discloses the preparation of certain 2-acyloxy alkanesulfonic acids. Similarly, U.S. Pat. Nos. 2,094,451 issued Sept. 28, 1937, to Guenther et al. and 2,086,215 issued July 6, 1937 to DeGroote disclose certain salts of beta-acetoxy alkanesulfonic acids. These references are hereby incorporated by reference.

Another class of anionic detergent compounds herein are the alkylated .alpha.-sulfocarboxylates, containing about 10 to about 23 carbon atoms, and having the formula ##EQU2## wherein R is C.sub.8 to C.sub.20 alkyl, M is a water-soluble cation as hereinbefore disclosed, preferably sodium ion, and R' is short-chain alkyl, e.g., methyl, ethyl, propyl, and butyl. These compounds are prepared by the esterification of .alpha.-sulfonated carboxylic acids, which are commercially available, using standard techniques. Specific examples of the alkylated .alpha.-sulfocarboxylates preferred for use herein include:

ammonium methyl-.alpha.-sulfopalmitate,

triethanolammonium ethyl-.alpha.-sulfostearate,

sodium methyl-.alpha.-sulfopalmitate,

sodium ethyl-.alpha.-sulfopalmitate,

sodium butyl-.alpha.-sulfostearate,

potassium methyl-.alpha.-sulfolaurate,

lithium methyl-.alpha.-sulfolaurate,

as well as mixtures thereof.

Another operable class of anionic organic detergents is that of the .beta.-alkyloxy alkane sulfonates. These compounds have the following formula: ##EQU3## where R.sub.1 is a straight chain alkyl group having from 6 to 20 carbon atoms, R.sub.2 is a lower alkyl group having from 1 (preferred) to 3 carbon atoms, and M is a water-soluble cation as hereinbefore described.

Specific examples of .beta.-alkyloxy alkane sulfonates, or alternatively 2-alkyloxy-alkane-1-sulfonates, having low hardness (calcium ion) sensitivity useful herein to provide superior cleaning levels under household washing conditions include:

potassium-.beta.-methoxydecanesulfonate,

sodium-2-methoxytridecanesulfonate,

potassium 2-ethoxytetradecylsulfonate,

sodium 2-isopropoxyhexadecylsulfonate,

lithium 2-t-butoxytetradecylsulfonate,

sodium .beta.-methoxyoctadecylsulfonate, and

ammonium .beta.-n-propoxydodecylsulfonate.

Other synthetic anionic detergents useful herein are alkyl ether sulfates. These materials have the formula RO(C.sub.2 H.sub.4 O).sub.x SO.sub.3 M wherein R is alkyl or alkenyl of about 10 to about 20 carbon atoms, x is 1 to 30, and M is a water-soluble cation as defined hereinbefore. The alkyl ether sulfates useful in the present invention are condensation products of ethylene oxide and monohydric alcohols having about 10 to about 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 be synthetic. Lauryl alcohol and straight chain alcohols derived from tallow are preferred herein. Such alcohols are reacted with 1 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 triethylene glycol ether sulfate; and sodium tallow alkyl hexaoxyethylene sulfate, and sodium tallow alkyl trioxyethylene sulfate.

Preferred herein for reasons of excellent cleaning properties and ready availability are the alkali metal coconut- and tallow-alkyl oxyethylene ether sulfates having an average of about 1 to about 10 oxyethylene moieties. The alkyl ether sulfates of the present invention are known compounds and are described in U.S. Pat. 3,332,876, to Walker (July 25, 1967), incorporated herein by reference.

Additional examples of anionic non-soap synthetic detergents which come within the terms of the present invention are the reaction product of fatty acids esterified 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 amides of methyl tauride in which the fatty acids, for example, are derived from coconut oil. Other anionic synthetic detergents of this variety are set forth in U.S. Pat. Nos. 2,486,921; 2,486,922; and 2,396,278.

Additional examples of anionic, non-soap, synthetic detergents, which come within the terms of the present invention, are the compounds which contain two anionic functional groups. These are referred to as di-anionic detergents. Suitable di-anionic detergents are the disulfonates, disulfates, or mixtures thereof which may be represented by the following formulae:

where R is an acyclic aliphatic hydrocarbyl group having 15 to 20 carbon atoms and M is a water-solubilizing cation, for example, the C.sub.15 to C.sub.20 disodium 1,2-alkyldisulfates, C.sub.15 to C.sub.20 dipotassium-1,2-alkyldisulfonates or disulfates, disodium 1,9-hexadecyl disulfates, C.sub.15 to C.sub.20 disodium-1,2-alkyldisulfonates, disodium 1,9-stearyldisulfates and 6,10 -octadecyldisulfates.

The aliphatic portion of the disulfates or disulfonates is generally substantially linear, thereby imparting desirable biodegradable properties to the detergent compound.

The water-solubilizing cations include the customary cations known in the detergent art, i.e., the alkali metals, and the ammonium cations, as well as other metals in group IIA, IIB, IIIA, IVA and IVB of the Periodic Table except for boron. The preferred water-solubilizing cations are sodium or potassium. These dianionic detergents are more fully described in British Letters Patent 1,151,392 which claims priority on an application made in the U.S.A. (Ser. No. 564,556) on July 12, 1966, now abandoned.

Still other anionic synthetic detergents include the class designated as succinamates. This class includes such surface active agents as disodium N-octadecylsulfosuccinamate; tetrasodium N-(1,2-dicarboxyethyl)-N-octadecylsulfo-succinamate; diamyl ester of sodium sulfosuccinic acid; dihexyl ester of sodium sulfosuccinic acid; dioctyl esters of sodium sulfosuccinic acid.

Other suitable anionic detergents utilizable herein are olefin sulfonates having about 12 to about 24 carbon atoms. The term "olefin sulfonates" is used herein to mean compounds which can be produced by the sulfonation of .alpha.-olefins by means of uncomplexed sulfur trioxide, followed by neutralization of the acid reaction mixture in conditions such that any sultones which have been formed in the reaction are hydrolyzed to give the corresponding hydroxy-alkane-sulfonates. The sulfur trioxide can be liquid or gaseous, and is usually, but not necessarily, diluted by inert diluents, for example by liquid SO.sub.2, chlorinated hydrocarbons, etc., when used in the liquid form, or by air, nitrogen, gaseous SO.sub.2, etc., when used in the gaseous form.

The .alpha.-olefins from which the olefin sulfonates 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 1-dodecene; 1-tetradecene; 1-hexadecene; 1-octadecene; 1-eicosene and 1-tetracosene.

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

A specific anionic detergent which has also been found excellent for use in the present invention is described more fully in the U.S. Pat. 3,332,880 of Phillip F. Pflaumer and Adrian Kessler, issued July 25, 1967, titled "Detergent Composition", the disclosure of which is incorporated herein by reference.

Of all the above-described types of anionic surfactants, preferred types include (a) the sodium and potassium salts of fatty alcohols, said alcohols containing from about 8 to 18 carbon atoms; (b) the sodium and potassium salts of alkyl benzene sulfonic acids in which the alkyl group contains from about 9 to 20 carbon atoms; (c) the sodium and potassium salts of sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol containing from about 8 to 18 carbon atoms with from 1 to about 6 moles of ethylene oxide; (d) compounds of the formula: ##EQU4## wherein R.sub.1 is alkyl of about 9 to 23 carbon atoms, R.sub.2 is alkyl of 1 to about 8 carbon atoms and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium; (e) compounds of the formula: ##EQU5## wherein R is an alkyl group of about 8 to 20 carbon atoms, R' is an alkyl group of 1 to about 4 carbon atoms, and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium; (f) compounds of the formula: ##EQU6## wherein R.sub.1 is a linear alkyl group of from about 6 to 20 carbon atoms, R.sub.2 is an alkyl group of from 1 to about 3 carbon atoms and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium; (g) olefin sulfonates containing from about 12 to 24 carbon atoms; and (h) mixtures of these types of anionic surfactants.

Additional Components of the Spray-Dried Granules

In addition to the anionic surfactant, the spray-dried granules of the instant compositions can optionally contain a wide variety of non-surfactant materials. Most commonly, such granules include inorganic filler materials such as sodium sulfate and processing aids such as alkali metal acetate and silicate salts (particularly sodium acetate and sodium silicate). Although inert, such fillers, stabilizers and processing aids generally comprise most of the spray-dried detergent granule.

Other optional components of the spray-dried granule include such minor materials as brighteners and fluorescers, corrosion inhibiting agents, enzymes, bleaching agents, perfumes, coloring agents and moisture.

Preparation of Spray-Dried Granules

Spray-dried granules of the instant detergent compositions are prepared in conventional manner by admixing the granule components in a crutcher with water and spray-drying the resulting slurry in standard spray-drying equipment. Spray-dried particles of the instant composition generally range in size from about 149 microns to about 1410 microns, preferably from about 300 microns to about 1000 microns.

CARRIER GRANULES

From about 30% to about 80%, preferably from about 45% to about 55%, by weight of the instant detergent compositions consist essentially of sodium silicate carrier granules having absorbed therein a nonionic surfactant.

The Sodium Silicate Carrier Material

Sodium silicate is a common silicon-containing compound and is available commercially in many different physical and chemical forms. Water-soluble sodium silicate can be crystalline or amorphous, hydrated or anhydrous and can have varying ratios of sodium oxide (Na.sub.2 O) to silica (SiO.sub.2) within its structure.

Sodium silicates operable in the instant invention as carrier material are those which are amorphous in form, contain from about 2% to 12% by weight, preferably from about 4% to 8% by weight, of moisture and have a sodium oxide (Na.sub.2 O) to silica (SiO.sub.2) weight ratio of from about 1:1 to about 1:3.2, preferably from about 1:1.7 to 1:2.3. As will be discussed more fully below, the sodium silicate granules of the instant invention are "loaded" with a nonionic surfactant to form the carrier granules of the instant detergent composition. Hence, another parameter describing the sodium silicate material of the instant invention is its porosity, i.e. the extent to which nonionic surfactant can be absorbed into the silicate material. In general, the sodium silicate carrier material of the instant invention has a porosity of from about 0.4 to 1.2, preferably from about 0.6 to 1.0. Thus for the loaded carrier granules, the weight ratio of nonionic surfactant to sodium silicate varies between 0.4:1 to 1.2:1, preferably between 0.6:1 to 1.0:1.

The sodium silicate carrier granules of the instant detergent compositions can be prepared from aqueous slurries of sodium silicate material. Any convenient commercially-available form of sodium silicate can be employed. Such starting materials include sodium metasilicate, sodium sesquisilicate, and sodium orthosilicate having sodium oxide to silica weight ratios of from about 1:0.5 to 1:5.0. Although it is preferred to employ a sodium silicate raw material having the appropriate end product sodium oxide/silica ratio (i.e. 1:1 to 1:3.2), such ratios can be altered during preparation of the carrier granule by utilization of appropriate amounts of caustic or silicon dioxide in the aqueous silicate slurry during granule preparation. A highly preferred sodium silicate starting material for preparation of the instant carrier granules is Britesil CA sodium silicate marketed by the Philadelphia Quartz Company. This material has a sodium oxide/silica weight ratio of about 1:1.8.

The instant carrier granules can be prepared from the sodium silicate starting material by flashing an aqueous liquid dispersion or suspension of the sodium silicate starting material followed by air-drying of the resulting amorphous sodium silicate to yield sodium silicate of the proper moisture content and porosity. The aqueous slurry flashed in this manner generally comprises from about 45% to about 80% by weight sodium silicate, preferably about 70% by weight sodium silicate.

Flashing of the aqueous liquid dispersion or suspension involves superheating the water in the aqueous dispersion or suspension and subsequently forcing such a heated dispersion from a zone of relatively high pressure into a static unheated expansion zone of relatively low pressure. The process of flashing the sodium silicate slurry is described in greater detail in U.S. Pat. Nos. 3,450,494 and 3,674,700, incorporated herein by reference.

The sodium silicate material resulting from the above-described flashing operation is in the form of solid amorphous material having a moisture content of from about 15% to about 30% by weight. In order to prepare sodium silicate having the desired moisture content and porosity for use in the instant detergent compositions, this flashed material can be dried in conventional air-drying apparatus to reduce the moisture content of the carrier material to within the requisite range of from about 2% to about 12% by weight of sodium silicate. Such a drying operation yields amorphous sodium silicate having aa porosity within the 0.4 to 1.2 range specified above. Drying of the flashed sodium silicate with gases rich in carbon dioxide is preferably avoided inasmuch as CO.sub.2 tends to produce water-insoluble silicates during the drying process.

Sodium silicate prepared in this manner and having the above-specified physical and chemical characteristics is utilized in the form of particles varying in size between 149 microns to 1410 microns, preferably between 300 microns and 1000 microns. Sodium silicate particles of this size can be obtained by grinding the dried sodium silicate followed by conventional screening of the ground material.

The Nonionic Surfactant

The sodium silicate carrier granules prepared as described above are loaded with a nonionic surfactant compound to form the nonionic surfactant-containing carrier granules of the instant detergent compositions. Operable nonionic surfactants of the instant invention are those compounds derived by the condensation of an alkylene oxide (hydrophilic in nature) with an organic hydrophobic compound, which is usually aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene moiety which is condensed with any particular hydrophobic compound can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Examples of suitable nonionic surfactants are:

1. The polyethylene oxide condensates of alkyl phenols. These compounds include 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 configuration, with ethylene oxide, the 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 compounds may be derived, for example, from polymerized propylene, diisobutylene, octene, or nonene. Examples of compounds of this type include nonyl phenol condensed with about 9.5 moles of ethylene oxide per mole of nonyl phenol, dodecyl phenol condensed with about 12 moles of ethylene oxide per mole of phenol, dinonyl phenol condensed with about 15 moles of ethylene oxide per mole of phenol, di-isooctylphenol condensed with about 15 moles of ethylene oxide per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-630 marketed by the GAF Corporation; and Triton 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 may either be straight or branched and generally contains from about 8 to about 22 carbon atoms. Examples of such ethoxylated alcohols include the condensation product of about 6 moles of ethylene oxide with 1 mole of tridecanol, myristyl alcohol condensed with about 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 in length and wherein the condensate contains about 6 moles of ethylene oxide per mole of alcohol, and the condensation product of about 9 moles of ethylene oxide with the above-described coconut alcohol. Examples of commercially available nonionic surfactants of this type include Tergitol 15-S-9, Tergitol 15-S-7 and Tergitol 3-A-6, all marketed by the Union Carbide Corporation, Neodol 23-6.5, Neodol 25- 7 and Neodol 25-9, all marketed by the Shell Chemical Company and Kyro EOB marketed by The Proctor & 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 has a molecular weight of from about 1500 to 1800 and of course exhibits water insolubility. 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 about 50% of the total weight of the condensation product. Examples of compounds of this type include certain of the commercially available Pluronic surfactants 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 ethylene diamine and excess propylene oxide, said base having a molecular weight of from about 2500 to about 3000. This base is condensed with ethylene oxide to the extent that the condensation product contains from about 40% to about 80% by weight of polyoxyethylene and has a molecular weight of from about 5,000 to about 11,000. Examples of this type of nonionic surfactant include certain of the commercially available Tetronic compounds marketed by the Wyandotte Chemicals Corporation.

For use in the detergent compositions of the instant invention, the particular nonionic surfactant employed must have a hydrophilic-lipophilic balance (HLB) of from about 8 to about 15, preferably from about 10 to 14. Specific preferred nonionic surfactants within the range include the condensation product of one mole of secondary fatty alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide, the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide, the condensation product of one mole of coconut fatty acid with about 6 moles of ethylene oxide, the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide, Neodol 23-6.5, Neodol 25-7, Pluronic L-43, Triton X-45, Tetronic 1504, Tergitol 15-S-9 and Kyro EOB.

Highly preferred nonionic surfactants are the condensation product of one mole of coconut fatty acid with about 6 moles of ethylene oxide and Neodol 23-6.5. Neodol 23-6.5 is a nonionic detergent which is a condensation product of 1 mole of primary alcohol containing from 12 to 3 carbon atoms and an average of 6.5 ethylene oxide units. Neodol 25-7 is a nonionic detergent which is a condensation product of 1 mole of primary alcohol containing from 12 to 15 carbon atoms and an average of 7 moles of ethylene oxide.

Carrier Granule Loading

The above-described nonionic surfactant can be loaded into the above-described sodium silicate carrier granules merely by spraying the surfactant into a rotating drum containing the sodium silicate carrier granules. As noted above, nonionic sufactant is absorbed within the pores of the sodium silicate granules to an extent sufficient to provide a nonionic surfactant/sodium silicate weight ratio of from about 0.4:1 to about 1.2:1, preferably from about 0.6:1 to about 1.0:1.

Spraying of the nonionic material onto the carrier granules results in rather inefficient absorption of the nonionic material into the pores of the sodium silicate. In order to enhance absorption of nonionic surfactant into the granule interior and thereby reduce the extent to which the carrier granule is coated with nonionic surfactant, the carrier granules can either be sprayed with nonionic surfactant under vacuum conditions or the granules which have had the nonionic surfactant sprayed onto their surfaces can be subjected to a vacuum. Subsequent exposure of the vacuum treated granules to atmospheric pressure then completes the surfactant loading process. Use of a pressure driving force in this manner promotes the absorption of nonionic surfactant into the carrier granule and thereby improves the flow properties of detergent compositions containing such granules.

Sodium silicate granular particles prepared and loaded in the manner described above provide the means for introducing into the instant detergent compositions the requisite amount of nonionic surfactant. Such loaded carrier granules have excellent flow properties when incorporated into the instant detergent compositions. When the sodium silicate carrier granules have the nonionic surfactant absorbed within the carrier granule interior (as opposed to when carrier granules are merely coated with nonionic surfactant on their surfaces), such granules exhibit little bleeding of the nonionic sufactant and are thus relatively stable and free flowing after storage for extended periods of time.

In a preferred embodiment of the instant invention, bleeding of the nonionic surfactant (and thus deterioration of storage and flow properties of the instant detergent compositions) can be retarded even further by mixing with the liquid nonionic surfactant (before it is introduced into the carrier granules) an agent to harden (i.e. raise the melting point of) the nonionic surfactant. Hardening agents operable in this preferred embodiment of the instant invention are selected from the group consisting of fatty acid amides, fatty acids and mixtures thereof. The acyl moiety of operable fatty acid amides generally contains from about 10 to about 18 carbon atoms, preferably from about 12 to about 16 carbon atoms. Examples of suitable fatty acid amide hardening agents include lauric mono- and diethanol amides, stearic mono- and diethanol amides, dimethyl lauryl amide, myristic n-methylethanolamide, tallow acyl monoethanolamide, tallow acyl diethanolamide, coconut acyl ethanolamide, and coconut acyl amide. Preferred fatty acid amide hardening agents are those which have 12 to 16 carbon atoms in the acyl group and which are primary amides. These include middle cut coconut acyl primary amide, tallow acyl primary amide, stearic primary amide, palmitic primary amide and oleic primary amide.

Operable fatty acid hardening agents contain from about 8 to about 24 carbon atoms, preferably from about 10 to about 20 carbon atoms. Suitable fatty acids can be obtained from natural sources, such as, for example, plant or animal esters (e.g. palm oil, coconut oil, babassu oil, soybean oil, safflower oil, tall oil, castor oil, tallow, whale and fish oils, grease, lard, and mixtures thereof). The fatty acids can also be synthetically prepared (e.g., by the oxidation of petroleum or by hydrogenation of carbon monoxide via the Fischer-Tropsch process). Examples of suitable fatty acids for use as hardening agents in the instant invention include caproic acid, lauric acid, myristic acid, palmitic acid, stearic acid and palmitoleic acid. Preferred fatty acids include the fatty acids derived from coconut oil and tallow. Examples of commercially available fatty acids for use as hardening agents in the instant invention include C-105, C-108, C-110, T-10, T-11 and OL-910, all marketed by The Procter & Gamble Company, and Hyfac, a hydrogenated fish oil fatty acid marketed by Emery Industries, Inc. Fatty acids are not preferred hardening agents since they tend to render the sodium silicate carrier material less soluble. Generally, therefore, if fatty acids are employed as hardening agents, they are admixed with the above-described amides.

When the optional hardening agent is employed, it is admixed with the liquid nonionic surfactant prior to introducing the nonionic surfactant liquid into the sodium silicate carrier material. Hardening agent is generally added to the nonionic surfactant to the extent of from about 5% to about 25% by weight of the nonionic surfactant-hardening agent mixture. As noted, the function of the hardening agent is to raise the melting point of the nonionic surfactant-hardening agent mixture to thereby improve physical stability of the loaded sodium silicate carrier granules. Accordingly, when such a hardening agent is employed, the surfactant-hardening agent mixture is preferably sprayed into the chamber containing the sodium silicate carrier granules (which, as noted, can be vacuum treated) at elevated temperatures, i.e. those temperatures exceeding the melting point of the nonionic surfactant-hardening agent mixture. Generally, such elevated temperatures are above 120.degree.F.

OPTIONAL pH ADJUSTMENT AGENT GRANULE

In a preferred embodiment of the instant invention, substances can optionally be added to the mixture of spray-dried and carrier granules which serve to lower the pH of aqueous laundering solutions of the present compositions. Laundering solutions having pH's within the range of from about 7 to 8.5 are desirable from several detergency performance standpoints. Furthermore, solution pH's within the 7 to 8.5 range are desirable to enhance the stain-removal activity of other optional components of the instant composition such as enzymes and organic peracid bleaches. Such enzyme and bleach materials generally reach their point of maximum effectiveness within this near-neutral pH range.

Since the silicate carrier granule material essentially present in the present composition tends to render laundering solutions of such compositions somewhat alkaline (pH 9.5-10.5), a highly preferred optional component of the instant composition is a solid acidic pH adjustment agent sufficient to lower the pH of a 0.12% by weight aqueous solution of said composition to within the pH range of from about 7 to 8.5. Such a solid acidic pH adjustment agent can be any material which tends to neutralize the silicate-produced alkalinity of solutions of said composition but which does not tend to interact with the dry silicate carrier material to form insoluble material. Thus, operable pH adjustment agents are those "solid" organic or inorganic acids or acid mixtures which are in dry or solid form at room temperature, i.e. about 68.degree.F.

Examples of suitable pH adjustment agents include citric acid, tannic acid, tartaric acid, oxalic acid, maleic acid, gluconic acid, boric acid, glutamic acid, acetic acid, sulfamic acid, mixtures of citric acid and lauric acid and acid salts such as sodium bisulfate and sodium bicarbonate. A highly preferred pH adjustment agent is citric acid by virtue of its relatively low toxicity and its surprising compatibility with the silicate carrier material within the dry composition.

When employed, the optional solid acidic pH adjustment agent comprises from about 1% to 35% by weight, preferably from about 10% to 20% by weight, of the composition of the instant invention. Such materials necessarily do not comprise a portion of either the spray-dried, anionic surfactant-containing granules or the nonionic surfactant-containing silicate carrier granules. Rather the solid acidic pH adjustment agent represents a third distinct type of granular particle which is admixed with the essential spray-dried and carrier granules. The pH adjustment granules are preferably of approximately the same size as the essential spray-dried and carrier-granules, i.e. the ratio of the average pH adjustment agent granule size in microns to the average particle sizes in microns of the spray-dried and loaded carrier granules, preferably falls within the range of from about 0.5:1 to about 2.0:1.

COMPOSITION PREPARATION

The mixed surfactant detergent compositions of the instant invention are prepared simply by admixing the above-described anionic surfactant-containing, spray-dried granules and nonionic surfactant-containing carrier granules (and optionally the pH adjustment agent granules) in amounts sufficient to provide the requisite composition concentration of each granule type in the final formulation. It has been surprisingly discovered that under laundering solution conditions provided when compositions of the instant invention are dissolved in water to the extent of from about 0.06% to about 0.18% by weight, detergency performance is maximized when both the amounts of anionic and nonionic surfactant and the weight ratio of nonionic to anionic surfactant fall within particular ranges.

The anionic surfactant concentration within the instant detergent compositions must range from about 3% by weight to about 15% by weight, preferably from about 8% by weight to about 12% by weight. The nonionic surfactant concentration within the instant detergent composition must range from about 17% to about 23% by weight, preferably from about 19% to 21% by weight. The weight ratio of nonionic surfactant to anionic surfactant in the total composition must fall within the range of from about 8:1 to about 1.13:1. Preferably, the weight ratio of anionic to nonionic surfactant varies from about 2.5:1 to 1.5:1, most preferably, it is about 2.0:1.

It has been further discovered that flow properties of the granular concentrated detergent compositions of the instant invention can be maximized by utilizing spray-dried and carrier granules of approximately the same size. Accordingly, in the instant detergent compositions the ratio of the average particle size in microns of the spray-dried granules to the average particle size in microns of the loaded sodium silicate carrier granules must fall within the range of from about 0.5:1 to about 2.0:1. Preferably, this particle size ratio varies between 0.8:1 and 1.2:1.

The detergent compositions of the instant invention are added to water to provide a laundering liquor containing the instant dissolved compositions to the extent of from about 0.06% to about 0.18% by weight. This concentration is approximated when about 0.5 to 1.5 cups of the instant composition are added to the 17-23 gallons of water generally held by commercially-available washing machines. Washing solution pH provided by the instant compositions generally varies between 7.5 and 10. When no pH adjustment agent is employed, washing solution pH generally varies between 9.5 and 10.5. Optional low pH embodiments generally provide washing solution pH's between 7 and 8.5. Soiled fabrics are added to the laundering liquor and cleansed in the usual manner.

The mixed surfactant granular detergent compositions of the instant invention are illustrated by the following examples

EXAMPLE I

A phosphate-free, granular detergent composition is prepared by admixing spray-dried granular particles containing anionic surfactant with sodium silicate carrier granules having nonionic surfactant absorbed within the pores of the silicate carrier material.

The spray-dried granules have the following composition:

SPRAY-DRIED GRANULE ______________________________________ Component Wt. % of Granule ______________________________________ Sodium tallow alkyl sulfate 20% Sodium sulfate 74% Water 6% Average granule size (microns) 500 ______________________________________

The sodium silicate carrier granules have the following composition:

CARRIER GRANULE ______________________________________ Component Wt. % of Granule ______________________________________ Sodium silicate (Na.sub.2 O/SiO.sub.2 wt. ratio = 1:2.0; 7% by wt. bound moisture) 50% Condensation product of one mole of secondary aliphatic alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide (HLB -- 13.3) 50% Wt. ratio surfactant/carrier 1:1 Average granule size (microns) 500 ______________________________________

These two granule types are admixed to form a granular composition containing 40% by weight of the composition of the loaded nonionic granules and 60% by weight of the composition of the spray-dried granules. Anionic surfactant concentration in the composition is thus 12% by weight of the composition. Nonionic surfactant concentration in the composition is thus 20% by weight of the composition. The weight ratio of nonionic surfactant/anionic surfactant in the composition is 1.66:1. The ratio of average particle sizes of the two granule types is 1:1.

Such a composition provides excellent fabric cleaning when dissolved in conventional laundering solution to the extent of about 0.11% by weight (0.9 cup/17-23 gal. wash water). The composition, furthermore, has excellent flow properties and exhibits minimal bleeding from the carrier granule upon prolonged storage.

Substantially similar performance results and physical properties are realized when the sodium tallow alkyl sulfate in the Example II composition is replaced with an equivalent amount of sodium linear alkyl benzene sulfonate wherein the alkyl chain averages about 12 carbon atoms in length; 3-acetoxytridecane-1-sulfonic acid; sodium methyl-.alpha.-sulfopalmitate; sodium .beta.-methoxyoctadecylsulfonate; sodium coconut alkyl ethylene glycol ether sulfonate; the sodium salt of the sulfuric acid ester of the reaction product of one mole of tallow alcohol and three moles of ethylene oxide; or mixtures of these surfactants.

Substantially similar performance results and physical properties are realized when the secondary alcohol condensation product in the Example I composition is replaced with an equivalent amount of the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide (HLB = 13.5), the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide (HLB = 12.98), Neodol 23-6.5 (HLB = 12.0), Neodol 25-9 (HLB = 13.1), Pluronic L-43 (HLB = 12.0), Triton X-45 (HLB = 10.4), Tetronic 1504 (HLB = 12.5), Tergitol 15-S-9 (HLB = 13.3), or Kyro EOB (HLB = 13.3).

EXAMPLE II

A phosphate-free granular detergent composition is prepared by admixing spray-dried granular particles containing anionic surfactant with sodium silicate carrier granules having nonionic surfactant absorbed within the pores of the silicate carrier material.

The anionic surfactant-containing, spray-dried granules have the following composition:

SPRAY-DRIED GRANULE ______________________________________ Component Wt. % of Granule ______________________________________ Sodium linear alkyl benzene sulfonate wherein the alkyl group averages about 11.8 carbon atoms in length 18.18% Sodium silicate (Na.sub.2 O/SiO.sub.2 wt. ratio = 1:2.4) 5.0% Sodium sulfate 65.59% Sodium acetate 5.0% Brighteners 1.23% Moisture 5.0% Average granule size (microns) 500 microns ______________________________________

The sodium silicate carrier granules have the following composition:

CARRIER GRANULES ______________________________________ Component Wt. % of Granule ______________________________________ Sodium silicate (Na.sub.2 O/SiO.sub.2 wt. ratio = 1:1.8; 4% wt. bound moisture) 51.12% Condensation product of about 6 moles of ethylene oxide with coconut fatty alcohol (HLB = 12.0) 44.44% Middle cut coconut alkyl primary amide 4.44% Wt. ratio surfactant/silicate 0.867 Average granule size (microns) 500 ______________________________________

The two granule types are admixed to form a granular composition containing 45% by weight of the composition of the loaded carrier granules and 55% by weight of the composition of the spray-dried granules. Anionic surfactant concentration in the composition is thus 10% by weight of the composition. Nonionic surfactant concentration in the composition is thus 20% by weight of the composition. The weight ratio of nonionic surfactant to anionic surfactant in the composition is 2:1. The hardening agent comprises 9.2% by weight of the nonionic-hardening agent mixture. The ratio of average particle sizes of the two granule types is 1:1.

Such a composition provides excellent fabric cleaning when dissolved in conventional laundering solution to the extent of about 0.11% by weight (0.9 cup/17-23 gal. wash water). The composition, furthermore, has excellent flow properties and exhibits minimal bleeding from the carrier granule upon prolonged storage.

Substantially similar performance results and physical properties are realized when in the Example II composition the sodium linear alkyl benzene sulfonate is replaced with an equivalent amount of sodium tallow alkyl sulfate; sodium 2-acetoxytridecane-1-sulfonate; sodium methyl-.alpha.-sulfopalmitate; sodium .beta.-methoxyoctadecylsulfonate; sodium coconut alkyl ethylene glycol ether sulfonate; the sodium salt of the sulfonic acid ester of the reaction product of one mole of tallow alcohol and three moles of ethylene oxide; or mixtures of these surfactants.

Substantially similar performance results and physical properties are realized when the coconut alcohol condensation product in the Example II composition is replaced with an equivalent amount of the condensation product of one mole of secondary fatty alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide (HLB - 13.3), the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide (HLB = 13.5), the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide (HLB = 12.98), Neodol 23-6.5 (HLB = 12.0), Neodol 25-9 (HLB = 13.1), Pluronic L-43 (HLB = 12.0), Triton X-45 (HLB = 10.4), Tetronic 1504 (HLB = 12.5), Tergitol 15-S-9 (HLB = 13.3) or Kyro EOB (HLB = 13.3)

Substantially similar storage stability and flow properties are realized when in the Example II compositions, the middle coconut alkyl primary amide hardening agent is replaced with an equivalent amount of tallow acyl primary amide, stearic primary amide, palmitic primary amide, oleic primary amide, tallow acyl monoethanolamide, tallow acyl diethanolamide, tallow fatty acid, coconut fatty acid or mixtures of these hardening agents.

EXAMPLE III

A phosphate-free, low-pH granular detergent composition is prepared by admixing spray-dried granular particles containing anionic surfactant, sodium silicate granules having nonionic surfactant absorbed within the pores of the silicate carrier material and acidic pH adjustment agent granules.

The spray-dried granules have the following composition:

SPRAY-DRIED GRANULE ______________________________________ Component Wt. % of Granule ______________________________________ Sodium linear alkyl benzene sulfonate wherein the alkyl group averages about 11.8 carbon atoms in length 24.390% Sodium silicate (Na.sub.2 O/SiO.sub.2 wt. ratio = 1:2.4) 6.707% Sodium acetate 20.000% Sodium sulfate 43.254% Brighteners 1.649% Moisture 4.000% Average Granule Size (microns) 500 microns ______________________________________

The nonionic surfactant-containing sodium silicate carrier granules have the following composition:

CARRIER GRANULES ______________________________________ Component Wt. % of Granule ______________________________________ Sodium silicate (Na.sub.2 O/SiO.sub.2 wt. ratio = 1:1.8; 4% wt. bound moisture) 51.11 % Condensation product of about 6 moles of ethylene oxide with coconut fatty alcohol (HLB = 12.0) 44.445% Middle cut coconut alkyl primary amide 4.445% Wt. ratio nonionic/silicate 0.867 Average granule size (microns) 500 ______________________________________

The acidic pH adjustment agent granules have the following composition:

pH ADJUSTMENT AGENT GRANULES ______________________________________ Component Wt. % of Granule ______________________________________ Citric acid 100% Average Granule Size (microns) 500 microns ______________________________________

The three above-described granule types are admixed to form a granular composition containing 45% by weight of the composition of the loaded carrier granules, 40% by weight of the composition of the spray-dried granules and 15% by weight of the compositions of the pH adjustment agent granules. Anionic surfactant concentration in the composition is thus 10% by weight of the composition. Nonionic surfactant concentration in the composition is thus 20% by weight of the composition. The weight ratio of nonionic surfactant to anionic surfactant in the composition is 2:1. The hardening agent comprises 9.1% by weight of the nonionic-hardening agent mixture. The ratio of average particle sizes of the three granule types is 1:1:1.

Such a composition provides excellent low-pH fabric cleaning when dissolved in conventional laundering solution to the extent of about 0.11% by weight (0.9 cup/17-23 gal. wash water). The composition, furthermore, has excellent flow properties and exhibits minimal bleeding from the carrier granule upon prolonged storage.

Substantially similar performance results and physical properties are realized when in the Example III composition the sodium linear alkyl benzene sulfonate is replaced with an equivalent amount of sodium tallow alkyl sulfate; sodium 2-acetoxytridecane-1-sulfonate; sodium methyl-.alpha.-sulfopalmitate; sodium .beta.-methoxyoctadecylsulfonate; sodium coconut alkyl ethylene glycol ether sulfonate; the sodium salt of the sulfonic acid ester of the reaction product of one mole of tallow alcohol and three moles of ethylene oxide; or mixtures of these surfactants.

Substantially similar performance results and physical properties are realized when the coconut alcohol condensation product of the Example III composition is replaced with an equivalent amount of the condensation product of one mole of secondary fatty alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide (HLB = 13.3), the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide (HLB = 13.5), the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide (HLB = 12.98), Neodol 23-6.5 (HLB = 12.0), Neodol 25-9 (HLB = 13.1), Pluronic L-43 (HLB = 12.0), Triton X-45 (HLB = 10.4), Tetronic 1504 (HLB = 12.5), Tergitol 15-S-9 (HLB = 13.3) or Kyro EOB (HLB = 13.3).

Substantially similar storage stability and flow properties are realized when in the Example III compositions, the middle coconut alkyl primary amide hardening agent is replaced with an equivalent amount of tallow acyl primary amide, stearic primary amide, palmitic primary amide, oleic primary amide, tallow acyl monoethanolamide, tallow acyl diethanolamide, tallow fatty acid, coconut fatty acid or mixtures of these hardening agent.

Substantially similar performance results and physical properties are realized when the citric acid pH adjustment agent in the Example III composition is replaced with an equivalent amount of tannic acid, tartaric acid, maleic acid, gluconic acid, boric acid, glutamic acid, acetic acid, sulfamic acid, oxalic acid, mixtures of citric acid and lauric acid, sodium bisulfate or sodium bicarbonate.

CLEANING PERFORMANCE TEST

The ability of the compositions of the instant invention to clean fabrics is demonstrated by a cleaning performance test. Such a test involves measurement of removal of a particular type of soil from standard polyester/cotton swatches using laundering solutions containing the instant detergent compositions. The swatches tested are soiled with a mixture of air conditioner filter soil and an artificial lipid soil consisting of equal weight parts of oleic acid, octadecane and trioleum. Such a soil mixture simulates the type and amount of particulate and oily material commonly encountered in the washing liquor when a typical household laundry bundle is washed.

Swatches are washed in a mini-washer for 10 minutes under typical U.S. laundering conditions (100.degree.F., 7 grains/gal. hardness). The laundering solution contains 0.12% by weight of the composition to be tested (corresponding to a concentration to about 1 cup/17-19 gallons of water).

Increase in swatch whiteness is taken as an accurate indication of the effectiveness of soil removal by solutions of the detergent compositions tested. Whiteness increase is measured by means of a commercially available, photoelectric trichromatic colormeter, i.e. a Hunter Color and Color Difference Meter manufactured by Henry A. Gardner Laboratory, Inc. Hunter Meter Whiteness measurements, confirmed by visual evaluation, indicate that compositions of the instant invention having the particular essential anionic and nonionic surfactant levels and anionic/nonionic surfactant weight ratios (the Examples II and II compositions) provide excellent removal of the air conditioner filter soil/artificial lipid soil mixture from the swatches. Compositions having anionic and nonionic surfactant levels and/or nonionic/anionic weight ratios outside those of the instant invention are less effective in such soil removal as determined by the above-described test.

STORAGE STABILITY TEST

Determination of the storage stability of compositions of the instant invention is made by means of a storage stability test. Granular compositions tested are packed into outside waxed laminated cartons and stored in constant temperature-humidity chambers for various intervals of time. Such chambers generally are maintained at a temperature of 80.degree.F. and a relative humidity of 60%. At specific intervals of time, compositions being tested are removed from the constant temperature-humidity environments and tested to determine (1) how well the compositions flow from the cartons when poured, (2) the extent to which liquid nonionic surfactant is wicking into the container cardboard, and (3) composition solubility in water.

Comparisons of these factors are made between the composition of Examples II and III above and (1) similar compositions which have substantial amounts of nonionic surfactant adsorbed on the surfaces of the carrier granules, (2) similar compositions which have nonionic surfactant loaded into the sodium silicate carrier granules at higher levels than those of the instant invention, and (3) compositions of the instant invention which have no hardening agent added to the nonionic surfactant.

Such storage tests indicate that the compositions of the instant invention (Examples II, III and IV) having the nonionic surfactant absorbed within the pores of the sodium silicate carrier material are superior in flowability and wicking performance to similar compositions having nonionic surfactant adsorbed on the surfaces of the sodium silicate carrier material.

Compositions of the instant invention (including those of Examples II, III and IV) having nonionic surfactant/sodium silicate weight ratios within the specified 0.4:1 to 1.2:1 range are superior in flowability and wicking properties to similar compositions having nonionic surfactant/sodium silicate weight ratios above this range.

A preferred embodiment of the instant invention containing an amide hardening agent in the nonionic surfactant (Example II, III and IV compositions) is superior in wicking performance to similar compositions not employing such a hardening agent.

After such storage tests, compositions of the instant invention demonstrate flow properties, wicking performance properties, and product solubility which meet standards of consumer acceptability.

Claims

What is claimed is:

1. A granular detergent composition consisting essentially of:

A. from about 20% to 70% by weight of the composition of spray-dried granules comprising from about 5% to about 40% by weight of said spray-dried granules of an anionic surfactant; and

B. from about 30% to 80% by weight of the composition of nonionic surfactant-containing carrier granules comprising:

i. a water-soluble, porous amorphous sodium silicate carrier material having a weight ratio of Na.sub.2 O to SiO.sub.2 of from about 1:1 to 1:3.2 and a moisture content of from about 2% to about 12% by weight of the sodium silicate; and

ii. a nonionic surfactant derived by the condensation of alkylene oxide with an organic hydrophilic compound and having a hydrophilic-lipophilic balance between 8 and 15, said nonionic surfactant being absorbed within the pores of said sodium silicate carrier material in an amount sufficient to provide a weight ratio of nonionic surfactant to silicate carrier material of from about 0.4:1 to 1.2:1;

said spray-dried granules and said nonionic surfactant-containing carrier granules being present in said detergent composition in amounts sufficient to provide an anionic surfactant concentration within said composition of from about 3% by weight to about 15% by weight; a nonionic surfactant concentration within said composition of from about 17% to about 23% by weight and a nonionic surfactant to anionic surfactant weight ratio of from about 8:1 to about 1.13:1; the ratio of the average particle sizes of said spray-dried granules and said anionic surfactant-containing carrier granules varying between 0.5:1 to 2.0:1.

2. A composition in accordance with claim 1 wherein the anionic surfactant is selected from the group consisting of

a. the sodium and potassium salts of sulfated fatty alcohols, said alcohols containing from about 8 to 18 carbon atoms;

b. the sodium and potassium salts of alkyl benzene sulfonic acids in which the alkyl group contains from 9 to 20 carbon atoms;

c. the sodium and potassium salts of sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol containing from about 8 to 18 carbon atoms with from 1 to about 6 moles of ethylene oxide;

d. compounds of the formula ##EQU7## wherein R.sub.1 is alkyl of about 9 to 23 carbon atoms, R.sub.2 is alkyl of 1 to about 8 carbon atoms and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium;

e. compounds of the formula: ##EQU8## wherein R is an alkyl group of about 8 to 20 carbon atoms, R' is an alkyl group of 1 to about 4 carbon atoms, and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium;

f. compounds of the formula ##EQU9## wherein R.sub.1 is a linear alkyl group of from about 6 to 20 carbon atoms, R.sub.2 is an alkyl group of from 1 to about 3 carbon atoms, and M is a water-soluble cation selected from the group consisting of sodium, potassium, lithium, ammonium and substituted ammonium; and

g. olefin sulfonates containing from about 12 to 24 carbon atoms; and

wherein the nonionic surfactant has a hydrophilic-lipophilic balance between about 10 and 14.

3. A composition in accordance with claim 2 wherein

a. the ratio of sodium oxide to silicate in the sodium silicate carrier material ranges from about 1:1.7 to 1:2.3;

b. the sodium silicate carrier material contains from about 4% to about 8% moisture on a silicate-moisture basis;

c. the weight ratio of absorbed nonionic surfactant to sodium silicate carrier material ranges from about 0.6:1 to about 1.0:1; and

d. the weight ratio of nonionic surfactant to anionic surfactant in the detergent composition ranges from about 1.5:1 to 2.5:1.

4. A composition in accordance with claim 3 wherein

a. the anionic surfactant is selected from the group consisting of sodium linear alkyl benzene sulfonate wherein the alkyl chain averages from about 10 to 18 carbon atoms in length, sodium tallow alkyl sulfate; sodium 2-acetoxy-tridecane-1-sulfonate; sodium methyl-.alpha.-sulfopalmitate; sodium .beta.-methoxyoctadecylsulfonate; sodium coconutalkyl ethylene glycol ether sulfonate; the sodium salt of the sulfuric acid ester of the reaction product of one mole of tallow alcohol and three moles of ethylene oxide; and mixtures thereof, and

b. the nonionic surfactant is selected from the group consisting of the condensation product of one mole of secondary fatty alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide, the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide, the condensation product of one mole of coconut fatty acid with about 6 moles of ethylene oxide, the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide, a condensation product of one mole of primary alcohol containing from 12 to 13 carbon atoms and an average of 6.5 moles of ethylene oxide, a condensation product of one mole of primary alcohol containing from 12 to 15 carbon atoms and an average of 7.0 moles of ethylene oxide.

5. A composition in accordance with claim 4 wherein the anionic surfactant is sodium linear alkyl benzene sulfonate with the alkyl group averaging about 12 carbon atoms in length, and wherein the nonionic surfactant is selected from the group consisting of the condensation product of one mole of coconut fatty alcohol and with about 6 moles of ethylene oxide and a condensation product of one mole of primary alcohol containing from 12 to 13 carbon atoms and an average of 6.5 moles of ethylene oxide.

6. A composition in accordance with claim 2 wherein the nonionic surfactant contains a hardening agent selected from the group consisting of fatty acid amides containing from about 10 to about 18 carbon atoms in the fatty acid acyl moiety; fatty acids containing from about 8 to about 24 carbon atoms and mixtures thereof; said hardening agent being present in the nonionic surfactant to the extent of from about 5% to about 25% by weight of the nonionic surfactant-hardening agent mixture.

7. A composition in accordance with claim 6 wherein

a. the ratio of sodium oxide to silicate in the sodium silicate carrier material ranges from about 1:1.7 to 1:2.3;

b. the sodium silicate carrier material contains from about 4% to about 8% by weight moisture on a silicate-moisture basis;

c. the weight ratio of absorbed nonionic surfactant to sodium silicate carrier material ranges from about 0.6:1 to about 1.0:1; and

d. the weight ratio of nonionic surfactant to anionic surfactant in the detergent composition ranges from about 1.5:1 to 2.5:1.

8. A composition in accordance with claim 7 wherein

a. the anionic surfactant is selected from the group consisting of sodium linear alkyl benzene sulfonate wherein the alkyl chain averages from about 10 to 18 carbon atoms in length, sodium tallow alkyl sulfate; sodium 2-acetoxy-tridecane-1-sulfonate; sodium methyl-.alpha.-sulfopalmitate; sodium .beta.-methoxyoctadecylsulfonate; sodium coconut alkyl ethylene glycol ether sulfonate; the sodium salt of the sulfuric acid ester of the reaction product of one mole of tallow alcohol and three moles of ethylene oxide; and mixtures thereof; and

b. the nonionic surfactant is selected from the group consisting of the condensation product of one mole of secondary fatty alcohol containing about 15 carbon atoms with about 9 moles of ethylene oxide, the condensation product of one mole of nonyl phenol with about 9.5 moles of ethylene oxide, the condensation product of one mole of coconut fatty acid with about 6 moles of ethylene oxide, the condensation product of one mole of tallow fatty alcohol with about 11 moles of ethylene oxide, a condensation product of one mole of primary alcohol containing from 12 to 13 carbon atoms and an average of 6.5 moles of ethylene oxide, a condensation product of one mole of primary alcohol containing from 12 to 15 carbon atoms and an average of 7.0 moles of ethylene oxide.

9. A composition in accordance with claim 7 wherein the hardening agent is a primary fatty acid amide containing from about 12 to 16 carbon atoms in the fatty acid acyl group.

10. A composition in accordance with claim 9 wherein

a. the spray-dried granules comprise from about 40% to about 55% by weight of the composition and the anionic surfactant comprises from about 15% to about 25% by weight of the spray-dried granules;

b. the sodium silicate carrier granules comprise from about 45% to about 55% by weight of the composition;

c. the anionic surfactant concentration in the composition ranges between 8% and 12% by weight of the total composition;

d. the nonionic surfactant concentration in the composition ranges between 19% and 21% by weight of the total composition; and

e. the ratio of the average particle sizes of the spray-dried granules and the nonionic surfactant-containing carrier granules varies between about 0.1:1 and 1.2:1.

11. A composition in accordance with claim 10 wherein

a. the anionic surfactant is sodium linear alkyl benzene sulfonates with the alkyl group averaging about 12 carbon atoms in length;

b. the nonionic surfactant is selected from the group consisting of the condensation product of about 6 moles of ethylene oxide with one mole of coconut fatty alcohol, and a condensation product of one mole of primary alcohol containing from 12 to 13 carbon atoms and an average of 6.5 moles of ethylene oxide;

c. the hardening agent is selected from the group consisting of middle cut coconut acyl primary amide, tallow acyl primary amide, stearic primary amide, palmitic primary amide and oleic primary amide; and

d. the weight ratio of nonionic surfactant to anionic surfactant in the composition is about 2.0:1.

12. A composition in accordance with claim 2 which additionally contains from about 1% to 35% by weight of the composition of solid acidic pH adjustment agent granules sufficient to lower the pH of a 0.12% by weight aqueous solution of said composition to within the pH range of from about 7 to 8.5.

13. A composition in accordance with claim 6 which additionally contains from about 1% to 35% by weight of the composition of solid acidic pH adjustment agent granules sufficient to lower the pH of a 0.12% by weight aqueous solution of said composition to within the pH range of from about 7 to 8.5.

14. A composition in accordance with claim 9 which additionally contains from about 10% to 20% by weight of the composition of solid, acidic pH adjustment agent granules, said pH adjustment agent being selected from the group consisting of citric acid, tannic acid, tartaric acid, maleic acid, gluconic acid, boric acid, glutamic acid, acetic acid, sulfamic acid, oxalic acid, mixtures of citric acid and lauric acid, sodium bisulfate and sodium bicarbonate.

15. A composition in accordance with claim 11 which additionally contain from about 10% to 20% by weight of the composition of citric acid pH adjustment agent granules; the ratio of the average citric acid granule size to the average particle size of the spray-dried and loaded carrier granules falling within the range of from about 0.5:1 to about 2.0:1.