AU6625794A - Secondary (2,3) alkyl sulfate surfactants in mixed surfactant particles - Google Patents

Description

SECONDARY (2,3) ALKYL SULFATE

SURFACTANTS IN MIXED SURFACTANT PARTICLES FIELD OF THE INVENTION

The present invention relates to surfactant particles which comprise secondary (2,3) alkyl sulfate surfactants and one or more co-surfactants. The co-surfactants are believed to disrupt the crystallinity of the secondary (2,3) alkyl sulfates, and thereby substantially enhance the water solubility of the particles. The soluble particles are thus suitable for use in granular laundry compositions, even in cold water washing conditions.

BACKGROUND OF THE INVENTION

Host conventional granular detergent compositions contain mixtures of various detersive surfactants in order to remove a wide variety of soils and stains from surfaces. For example, various anionic surfactants, especially the alkyl benzene sulfonates, are useful for removing particulate soils, and various nonionic surfactants, such as the alkyl ethoxylates and alkylphenol ethoxylates are useful for removing greasy soils. One class of surfactants which has found limited use in various compositions where emulsification is desired comprises the secondary alkyl sulfates. The conventional secondary alkyl sulfates are available as generally pasty, random mixtures of sulfated linear and/or partially branched alkanes. Such materials have not come into widespread use in laundry detergents, since they offer no particular advantages over the alkyl benzene sulfonates. Moreover, they may tend to have a lower flash point than the alkyl benzene sulfonates.

Modern granular laundry detergents are being formulated in "condensed" form which offers substantial advantages, both to the consumer and to the manufacturer. For the consumer, the smaller package size attendant with condensed products provides ease-ofhandling and storage. For the manufacturer, unit storage costs, shipping costs and packaging costs are lowered.

The manufacture of acceptable condensed granular detergents is not without its difficulties. In a typical condensed formulation, the so-called "inert" ingredients such as sodium sulfate are deleted. However, such ingredients do play a role in enhancing the solubility of detergent particles; hence, the condensed form will often suffer from solubility problems. Moreover, conventional low-density detergent granules are usually prepared by spray-drying processes which result in porous detergent particles that are quite amenable to being solubilized in aqueous laundry liquors. By contrast, condensed formulations will typically comprise substantially less porous, high density detergent particles which are less amenable to solubilization. Overall, since the condensed form of granular detergents typically comprises particles which contain high levels of detersive ingredients with little room for solubilizing agents, and since such particles are intentionally manufactured at high bulk densities, the net result Is a substantial problem with regard to in-use solubility.

Moreover, the problems associated with "caking" or "clumping" of granular detergents can be accentuated in both spray-dried and condensed detergent products when mixtures of various surfactants and co-surfactants are used therein. The provision of crisp, free-flowing granular detergents remains a challenge to the formulator.

It has now been discovered that a particular sub-set of the class of secondary alkyl sulfates, referred to herein as secondary (2,3) alkyl sulfates ("SAS"), offers considerable advantages to the formulator and user of detergent compositions. For example, the secondary alkyl (2,3) sulfates are available as dry, particulate solids which are more soluble in aqueous media than their counterpart primary alkyl sulfates of comparable chain lengths. Accordingly, they can be formulated as readily-soluble, high-surfactant (i.e., "high-active") particles for use in granular laundry detergents. Moreover, it has now been determined that the solubility of the particulate secondary (2,3) alkyl sulfates allows them to be formulated in the concentrated, high density form now coming into vogue with granular laundry detergents. Since, with proper care in manufacturing, the secondary (2,3) alkyl sulfates are available in solid, particulate form, they can be dry-mixed into granular detergent compositions without the need for passage through spray drying towers. In addition to the foregoing advantages seen for the secondary (2,3) alkyl sulfates, it has now been determined that they are both aerobically and anaerobically degradable, which assists in their disposal in the environment. Moreover, they exhibit increased compatibility with detergent enzymes, especially in the presence of calcium ions.

Importantly, it has now been discovered that the particulate secondary (2,3) alkyl sulfates can be combined with various co-surfactants to yield high-active, mixed surfactant particles which are free-flowing and have a decreased tendency to cake or clump. Moreover, there has now been found to be a substantial and remarkable improvement in cold water solubility as a result of the blending the secondary (2,3) alkyl sulfates (SAS) herein with various co-surfactants, especially polyhydroxy fatty acid amide surfactants (PFAS), alkyl ethoxylate surfactants (AE) and primary alkyl sulfate surfactants (AS) to provide mixed SAS/PFAS/AE/AS particles. While not intending to be limited by theory, it appears that this increase in solubility may be due to the disruption of the crystallinity of the SAS by the co-surfactants. Whatever the reason, the improved solubility is of substantial benefit under cold water conditions (e.g., at temperatures in the range of 5ºC to about 30ºC) where the rate of solubility of granular detergents in an aqueous washing liquor can be problematic. Of course, the improved solubility achieved herein is also of substantial benefit when preparing the modern compact or dense detergent granules where solubility can be problematic. The mixed particles provided by this invention can be used to prepare fully-formulated granular laundry detergents, both of the low density and high density types.

BACKGROUND ART

Various means and apparatus suitable for preparing granules have been disclosed in the literature and some have been used in the detergency art. See, for example: U.S. 5,133,924

EP-A-367,339 EP-A-390,251; EP-A-340,013; EP-A-327,963 EP-A-337,330 EP-B-229,671; EP-B2-191,396; JP-A-6,106,990 EP-A-342,043 GB-B-2,221,695; EP-B-240,356; EP-B-242,138 EP-A-242,141 U.S. 4,846,409; EP-A-420,317; U.S. 2,306,698 EP-A-264,049 U.S. 4,238,199; DE 4,021,476. Detergent compositions with various "secondary" and branched alkyl sulfates are disclosed in various patents; see: U.S. 2,900,346, Fowkes et al, August 18, 1959; U.S. 3,468,805, Grifo et al, September 23, 1969; U.S. 3,480,556, DeWitt et al, November 25, 1969; U.S. 3,681,424, Bloch et al, August 1, 1972; U.S. 4,052,342, Fernley et al, October 4, 1977; U.S. 4,079,020, Mills et al, March 14, 1978; U.S. 4,235,752, Rossall et al, November 25, 1980; U.S. 4,529,541, Wilms et al, July 16, 1985; U.S. 4,614,612, Reilly et al, September 30, 1986; U.S. 4,880,569, Leng et al, November 14, 1989; U.S. 5,075,041, Lutz, December 24, 1991; U.K. 818,367, Bataafsche Petroleum, August 12, 1959; U.K. 1,585,030, Shell, February 18, 1981; GB 2,179,054A, Leng et al, February 25, 1987 (referring to GB 2,155,031). U.S. Patent 3,234,258, Morris, February 8, 1966, relates to the sulfation of alpha olefins using H₂SO₄, an olefin reactant and a low boiling, nonionic, organic crystallization medium.

SUMMARY OF THE INVENTION

The present invention relates to the use of solid, secondary (2,3) alkyl sulfate surfactants to prepare "high-active", water-soluble surfactant particles containing, in one embodiment, at least about 80%, and in another embodiment at least about 35%, by weight of a mixture of detersive surfactants which comprises said secondary (2,3) alkyl sulfate surfactant in combination with one or more solubilizing co-surfactants.

The invention thus encompasses surfactant particles which comprise at least about 80% by weight of total surfactants, said surfactants comprising a mixture of:

(a) a C₁₀-C₂₀ secondary (2,3) alkyl sulfate surfactant; and

(b) at least about 1% by weight of a solubilizing co-surfactant.

Preferred particles of the foregoing type preferably comprise at least about 40%, more preferably at least about 75% by weight of C₁₄-C₁₈ secondary (2,3) alkyl sulfate surfactant, or mixtures thereof.

One type of particle according to this invention is wherein the co-surfactant is a nonionic surfactant which preferably comprises no more than about 25% by weight of the surfactant mixture. Suitable nonionic co-surfactants are members selected from the group consisting of ethoxylated alcohols, ethoxylated alkyl phenols, polyhydroxy fatty acid amide amides, and alkyl polyglycosides, and fatty ethanol amides.

Other useful co-surfactants in the aforesaid particles include alkyl ethoxy sulfates and primary alkyl sulfates. In another mode, the co-surfactant component can comprise a mixture of polyhydroxy fatty acid amide, primary alkyl sulfate and alkyl ethoxy sulfate, typically at ratios of about 1:1:1.

Preferred, non-tacky, free-flowing particles herein are those wherein the moisture content of the surfactants plus co-surfactants used to prepare the particles is less than about 20% by weight during the formulation process.

It should be recognized that the formulator may desire to include nonionic surfactants in amounts greater than 20% of the surfactant mixture. Inclusion in these larger proportions can be beneficial for solubility and performance, but is often difficult because of either the liquid nature of the nonionic surfactant, or the limited solubility of the solid nonionic surfactant.

The use of dry solid secondary (2,3) alkyl sulfate surfactant compositions of greater than 20% nonionics facilitates particle formation and solubility of both components, but usually requires the use of auxiliary dry ingredients to form a free-flowing particle. In such instances, dry ingredients may need to be included at proportions in excess of 20% of the particle, often in excess of 50% of the particle.

The invention thus also encompasses a water-soluble agglomerated surfactant particle containing at least about 35% by weight of total surfactants comprising:

(a) at least about 35%, preferably at least about 40%, by weight of said total surfactants of a C₁₀-C₂₀, preferably C₁₄-C₁₈, secondary (2,3) alkyl sulfate surfactant;

(b) at least about 20% by weight of total surfactants of a solubilizing co-surfactant;

(c) the balance of the agglomerated particle comprising conventional, powdered detergent ingredients and fillers.

Such agglomerated particles are those wherein the co-surfactant is a member selected from the group consisting of nonionic ethoxylated alcohols, ethoxylated alkyl phenols, polyhydroxy fatty acid amides, alkyl polyglycosides, fatty ethanol amides, and mixtures thereof, or anionic primary alkyl sulfates, alkyl ethoxy sulfates, and mixtures thereof, or mixtures of said nonionic and anionic co-surfactants.

Preferred agglomerates are those wherein the powdered ingredient (c) is selected from zeolite builders, layered silicate builders and mixtures thereof. Conventional solid fillers such as talc, or various nonhygroscopic silicates, sodium carbonate, sodium sulfate, and the like can also be used as the powdered ingredient (c).

The surfactant particles herein will preferably comprise the surfactant:cosurfactant (or mixture of co-surfactants) at a weight ratio of from about 10:1 to about 1:1, preferably about 7:1 to about 3:1.

A variety of co-surfactants can be used as the "crystallinity-disrupting" material which enhances the solubility of the mixed particles herein. For example, various ethoxylated C₁₂-C₁₈ alcohols such as C₁₄EO(5), C₁₆(EO)₃ and the like can be used. However, such materials are generally liquids and may tend to cause the mixed particles to be undesirably tacky. If used, such liquid nonionics preferably comprise no more than 20% by weight of the particles.

One class of especially suitable nonionic co-surfactants herein comprises the polyhydroxy fatty acid amide surfactant (PFAS) such as the C₁₂-C₁₈ NC₁-C₆ alkyl glucamides disclosed more fully hereinafter. This class of nonionic surfactants has the advantage that they exist as slightly waxy solids at room temperature. Hence, when blended with the solid secondary (2,3) alkyl sulfates herein, the PFAS materials do not tend to increase the tackiness of the final mixed particles.

Other co-surfactants useful herein for solubilizing purposes include C₁₂-C₁₈ primary alkyl sulfates, but it will be appreciated by the formulator that a variety of acceptable co-surfactants may be chosen from standard formularies. Binary, ternary, quaternary, etc. mixtures of the secondary (2,3) alkyl sulfate/co-surfactants may also be used. The particles herein exhibit excellent free-flow properties. However, in one mode the particles can be additionally coated with a finely-divided particulate free-flow agent. Free-flow agents which are members selected from the group consisting of zeolites, layered silicates, silicates, particulate secondary (2,3) alkyl sulfate surfactants, and mixtures thereof, can be used for such coating, as can nonparticulate agents such as gelatin and polyvinylalcohol.

All percentages, ratios and proportions herein are by weight, unless otherwise specified. All documents cited are incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION

Secondary (2.3) Alkyl Sulfate Surfactants For the convenience of the formulator, the following identifies and illustrates the differences between the sulfated surfactants employed herein and otherwise conventional alkyl sulfate surfactants.

Conventional primary alkyl sulfate surfactants have the general formula

ROSO₃-M⁺

wherein R is typically a linear C₁₀-C₂₀ hydrocarbyl group and M is a water-solubilizing cation. Branched-chain primary alkyl sulfate surfactants (i.e., branched-chain "PAS") having 10-20 carbon atoms are also known; see, for example, European Patent Application 439,316, Smith et al, filed 21.01.91.

Conventional secondary alkyl sulfate surfactants are those materials which have the sulfate moiety distributed randomly along the hydrocarbyl "backbone" of the molecule. Such materials may be depicted by the structure

CH₃(CH₂)n(CHOSO₃-M⁺)(CH₂)_mCH₃ wherein m and n are integers of 2 or greater and the sum of m + n is typically about 9 to 17, and M is a water-solubilizing cation.

By contrast with the above, the selected secondary (2,3) alkyl sulfate surfactants used herein comprise structures of formulas A and B

(A) CH₃(CH₂)x(CHOSO₃-M⁺) CH₃ and

(B) CH₃(CH₂)y(CHOSO3-M⁺) CH₂CH₃ for the 2-sulfate and 3-sulfate, respectively. Mixtures of the 2-and 3-sulfate can be used herein. In formulas A and B, x and (y+1) are, respectively, integers of at least about 6, and can range from about 7 to about 20, preferably about 10 to about 16. M is a cation, such as an alkali metal, ammonium, alkanol ammonium, alkaline earth metal, or the like. Sodium is typical for use as M to prepare the water-soluble (2,3) alkyl sulfates, but ethanolammonium, diethanolammonium, triethanolammonium, potassium, ammonium, and the like, can also be used. The C₁₀-C₂₀ secondary (2,3) alkyl sulfates can conveniently be employed herein. The C₁₄-C₁₈ compounds are preferred for laundry cleaning operations.

By the present invention it has been determined that the physical/chemical properties of the foregoing types of alkyl sulfate surfactants are unexpectedly different, one from another, in several aspects which are important to formulators of granular detergent compositions. For example, the primary alkyl sulfates can disadvantageously interact with, and even be precipitated by, metal cations such as calcium and magnesium. Thus, water hardness can negatively affect the primary alkyl sulfates to a greater extent than the secondary (2,3) alkyl sulfates. Accordingly, the secondary (2,3) alkyl sulfates have now been found to be preferred for use in the presence of calcium ions and under conditions of high water hardness, or in the so-called "under-built" situation which can occur when nonphosphate builders are employed.

Moreover, the solubility of the primary alkyl sulfates is not as great as the secondary (2,3) alkyl sulfates. Hence, the formulation of high-active, flowable, soluble surfactant particles and has now been found to be simpler and more effective with the secondary (2,3) alkyl sulfates than with the primary alkyl sulfates.

With regard to the random secondary alkyl sulfates (i.e., secondary alkyl sulfates with the sulfate group at positions such as the 4, 5, 6, 7, etc. secondary carbon atoms), such materials tend to be tacky solids or, more generally, pastes. Thus, the random alkyl sulfates do not afford the processing advantages associated with the solid secondary (2,3) alkyl sulfates when formulating mixed detergent particles in the manner of this invention. It is preferred that the secondary (2,3) alkyl sulfates be substantially free (i.e., contain less than about 20%, preferably less than about 10%, most preferably less than about 5%) of such random secondary alkyl sulfates.

One additional advantage of the secondary (2,3) alkyl sulfate surfactants herein over other positional or "random" alkyl sulfate isomers is in regard to the improved benefits afforded by said secondary (2,3) alkyl sulfates with respect to soil redeposition in the context of fabric laundering operations. As is well-known to users, laundry detergents loosen soils from fabrics being washed and suspend the soils in the aqueous laundry liquor. However, as is well-known to detergent formulators, some portion of the suspended soil can be redeposited back onto the fabrics. Thus, some redistribution and redeposition of the soil onto all fabrics in the load being washed can occur. This, of course, is undesirable and can lead to the phenomenon known as fabric "greying". (As a simple test of the redeposition characteristics of any given laundry detergent formulation, unsoiled white "tracer" cloths can be included with the soiled fabrics being laundered. At the end of the laundering operation the extent that the white tracers deviate from their initial degree of whiteness can be measured photometrically or estimated visually by skilled observers. The more the tracers' whiteness is retained, the less soil redeposition has occurred.)

It has now been determined that the secondary (2,3) alkyl sulfates afford substantial advantages in soil redeposition characteristics over the other positional isomers of secondary alkyl sulfates in laundry detergents, as measured by the cloth tracer method noted above. Thus, the selection of secondary (2,3) alkyl sulfate surfactants according to the practice of this invention which preferably are substantially free of other positional secondary isomers unexpectedly assists in solving the problem of soil redeposition in a manner not heretofore recognized.

It is to be noted that the secondary (2,3) alkyl sulfates used herein are quite different in several important properties from the secondary olefin sulfonates (e.g., U.S. Patent 4,064,076, Klisch et al, 12/20/77); accordingly, the secondary sulfonates are not the focus of the present invention. The preparation of the secondary (2,3) alkyl sulfates of the type useful herein can be carried out by the addition of H2SO4 to olefins. A typical synthesis using α-olefins and sulfuric acid is disclosed in U.S. Patent 3,234,258, Morris, or in U.S. Patent 5,075,041, Lutz, granted December 24, 1991. The synthesis, conducted in solvents which afford the secondary (2,3) alkyl sulfates on cooling, yields products which, when purified to remove the unreacted materials, randomly sulfated materials, unsul fated by-products such as C₁₀ and higher alcohols, secondary olefin sulfonates, and the like, are typically 90+% pure mixtures of 2- and 3-sulfated materials (up to 10% sodium sulfate is typically present) and are white, non-tacky, apparently crystalline, solids. Some 2,3-disulfates may also be present, but generally comprise no more than 5% of the mixture of secondary (2,3) alkyl mono-sulfates. Such materials are available as under the name "DAN", e.g., "DAN 200" from Shell Oil Company.

If increased solubility of the "crystalline" secondary (2,3) alkyl sulfate surfactants is desired, the formulator may wish to employ mixtures of such surfactants having a mixture of alkyl chain lengths. Thus, a mixture of C₁₂-C₁₈ alkyl chains will provide an increase in solubility over a secondary (2,3) alkyl sulfate wherein the alkyl chain is, say, entirely C₁₆.

If desired, the secondary (2,3) alkyl sulfates can be further purified to remove unwanted sodium sulfate. Various means can be used to lower the sodium sulfate content of the secondary (2,3) alkyl sulfates. For example, when the H₂SO₄ addition to the olefin is completed, care can be taken to remove unreacted H₂SO₄ before the acid form of the secondary (2,3) alkyl sulfate is neutralized. In another method, the sodium salt form of the secondary (2,3) alkyl sulfate which contains sodium sulfate can be rinsed with water at a temperature near or below the Krafft temperature of the sodium secondary (2,3) alkyl sulfate. This will remove Na₂SO₄ with only minimal loss of the desired, purified sodium secondary (2,3) alkyl sulfate. Of course, both procedures can be used, the first as a pre-neutralization step and the second as a post-neutralization step.

The term "Krafft temperature" as used herein is a term of art which is well-known to workers in the field of surfactant sciences. Krafft temperature is described by K. Shinoda in the text "Principles of Solution and Solubility", translation in collaboration with Paul Becher, published by Marcel Dekker, Inc. 1978 at pages 160-161. Stated succinctly, the solubility of a surface active agent in water increases rather slowly with temperature up to that point, i.e., the Krafft temperature, at which the solubility evidences an extremely rapid rise. At a temperature approximately 4ºC above the Krafft temperature a solution of almost any composition becomes a homogeneous phase. In general, the Krafft temperature of any given type of surfactant, such as the secondary (2,3) alkyl sulfates herein which comprise an anionic hydrophilic sulfate group and a hydrophobic hydrocarbyl group, will vary with the chain length of the hydrocarbyl group. This is due to the change in water solubility with the variation in the hydrophobic portion of the surfactant molecule.

In the practice of the present invention the formulator may optionally wash the secondary (2,3) alkyl sulfate surfactant which is contaminated with sodium sulfate with water at a temperature that is no higher than the Krafft temperature, and which is preferably lower than the Krafft temperature, for the particular secondary (2,3) alkyl sulfate being washed. This allows the sodium sulfate to be dissolved and removed with the wash water, while keeping losses of the secondary (2,3) alkyl sulfate into the wash water to a minimum.

Under circumstances where the secondary (2,3) alkyl sulfate surfactant herein comprises a mixture of alkyl chain lengths, it will be appreciated that the Krafft temperature will not be a single point but, rather, will be denoted as a "Krafft boundary". Such matters are well-known to those skilled in the science of surfactant/solution measurements. In any event, for such mixtures of secondary (2,3) alkyl sulfates, it is preferred to conduct the optional sodium sulfate removal operation at a temperature which is below the Krafft boundary, and preferably below the Krafft temperature of the shortest chain-length surfactant present in such mixtures, since this avoids excessive losses of secondary (2,3) alkyl sulfate to the wash solution. For example, for C₁₆ secondary sodium alkyl (2,3) sulfate surfactants, it is preferred to conduct the washing operation at temperatures below about 30ºC, preferably below about 20ºC. It will be appreciated that as the cation is changed, the Krafft temperature of the secondary (2,3) alkyl sulfate will change; hence, the washing temperature should be adjusted appropriately.

The washing process can be conducted batchwise by suspending wet or dry secondary (2,3) alkyl sulfates in sufficient water to provide 10-50% solids, typically for a mixing time of at least 10 minutes at about 22ºC (for a C₁₆ secondary [2,3] alkyl sulfate), followed by pressure filtration. In a preferred mode, the slurry will comprise somewhat less than 35% solids, inasmuch as such slurries are free-flowing and amenable to agitation during the washing process.

As an additional benefit, the washing process also reduces the levels of organic contaminants which comprise the random secondary alkyl sulfates noted above.

Co-Surfactants

The mixed detergent particles herein contain various anionic, nonionic, zwitterionic, etc. co-surfactants. Such co-surfactants are typically present at levels of from about 5% to about 50% by weight of the particles. Nonlimiting examples of co-surfactants useful herein include the conventional C₁₁-C₁₈ alkyl benzene sulfonates and primary and random alkyl sulfates (having due regard for their solubility and tendency toward tackiness, as noted above), the C₁₀-C₁₈ alkyl alkoxy sulfates (especially EO 1-5 ethoxy sulfates), the C₁₀-C₁₈ alkyl alkoxy carboxylates (especially EO 1-5 ethoxy carboxylates), the C₁₀-C₁₈ alkyl polyglycosides and their corresponding sulfated polyglycosides, C₁₂-C₁₈ alpha-sulfonated fatty acid esters, C₁₂-C₁₈ alkyl and alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C₁₂-C₁₈ betaines and sulfobetaines ("sultaines"), C10-C18 amine oxides, and the like. Other conventional useful surfactants are listed in standard texts. Preferred particles herein are substantially free of alkyl benzene sulfonates. Indeed, one advantage of the present invention is that it provides a replacement for such surfactants in laundry compositions. One particular class of nonionic co-surfactants especially useful herein comprises the polyhydroxy fatty acid amide surfactant materials (PFAS) of the formula:

wherein: R¹ is H, C₁-C₈ hydrocarbyl, 2-hydroxyethyl, 2-hydroxypropyl, or a mixture thereof, preferably C₁-C₄ alkyl, more preferably C₁ or C₂ alkyl, most preferably C₁ alkyl (i.e., methyl); and R₂ is a C₅-C₃₂ hydrocarbyl moiety, preferably straight chain C₇-C₁₉ alkyl or alkenyl, more preferably straight chain C₉-C₁₇ alkyl or alkenyl, most preferably straight chain C₁₁-C₁₉ alkyl or alke nyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 2 (in the case of glyceraldehyde) or at least 3 hydroxyls (in the case of other reducing sugars) directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z preferably will be derived from a reducing sugar in a reductive amination reaction; more preferably Z is a glycityl moiety. Suitable reducing sugars include glucose, fructose, maltose, lactose, galactose, mannose, and xylose, as well as glyceraldehyde. As raw materials, high dextrose corn syrup, high fructose corn syrup, and high maltose corn syrup can be utilized as well as the individual sugars listed above. These corn syrups may yield a mix of sugar components for Z. It should be understood that it is by no means intended to exclude other suitable raw materials. Z preferably will be selected from the group consisting of -CH₂-(CHOH)_n-CH₂OH, -CH(CH₂OH)-(CHOH)_n-1-CH₂OH, -CH₂-(CHOH)₂(CHOR')(CHOH)-CH₂OH, where n is an integer from 1 to 5, inclusive, and R' is H or a cyclic mono- or polysaccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4, particularly -CH₂-(CHOH)₄-CH₂OH.

In Formula (I), R¹ can be, for example, N-methyl, N-ethyl, N-propyl, N-isopropyl, N-butyl, N-isobutyl, N-2-hydroxy ethyl, or N-2-hydroxy propyl. For highest sudsing, R¹ is preferably methyl or hydroxyalkyl. If low sudsing is desired, R¹ is preferably C₂-C₈ alkyl, especial ly n-propyl, iso-propyl, n-butyl, iso-butyl, pentyl, hexyl and 2-ethyl hexyl. R²-CO-N< can be, for example, cocamide, stearamide, oleamide, lauramide, myristamide, capricamide, palmitamide, tallowamide, etc.

While polyhydroxy fatty acid amides can be made by the process of Schwartz, U.S. 2,703,798, contamination with cyclized by-products and other colored materials can be problematic. As an overall proposition, the preparative methods described in WO-9,206,154 and WO-9,206,984 will afford high quality polyhydroxy fatty acid amides. The methods comprise reacting N-alkylamino polyols with, preferably, fatty acid methyl esters in a solvent using an alkoxide catalyst at temperatures of about 85ºC to provide high yields (90-98%) of polyhydroxy fatty acid amides having desirable low levels (typically, less than about 1.0%) of sub-optimally degradable cyclized by-products and also with improved color and improved color stability, e.g., Gardner Colors below about 4, preferably between 0 and 2. (With compounds such as butyl, iso-butyl and n-hexyl, the methanol introduced via the catalyst or generated during the reaction provides sufficient fluidization that the use of additional reaction solvent may be optional.) If desired, any unreacted N-alkylamino polyol remaining in the product can be acylated with an acid anhydride, e.g., acetic anhydride, maleic anhydride, or the like, to minimize the overall level of such residual amines in the product. Residual sources of classical fatty acids, which can suppress suds, can be depleted by reaction with, for example, triethanolamine.

By "cyclized by-products" herein is meant the undesirable reaction by-products of the primary reaction wherein it appears that the multiple hydroxyl groups in the polyhydroxy fatty acid amides can form ring structures which are, in the main, not readily biodegradable. It will be appreciated by those skilled in the chemical arts that the preparation of the polyhydroxy fatty acid amides herein using the di- and higher saccharides such as maltose will result in the formation of polyhydroxy fatty acid amides wherein linear substituent Z (which contains multiple hydroxy substituents) is naturally "capped" by a polyhydroxy ring structure. Such materials are not cyclized by-products, as defined herein. The foregoing polyhydroxy fatty acid amides can also be sulfated, e.g., by reaction with S03/pyridine, and the resulting sulfated material used as an anionic co-surfactant herein.

Mixed Particles

The excellent free-flow properties and water solubility of the secondary (2,3) alkyl sulfates allow the formulator to prepare high-active content detergent particles which comprise a mixture of the secondary (2,3) alkyl sulfates and one or more of the co-surfactants. Such "high-active content" particles can comprise 35% by weight of particles and greater, preferably 80% and greater, most preferably 90% and greater, of the mixture of secondary (2,3) alkyl sulfate surfactant plus co-surfactant. Such mixtures used in said particles will typically comprise at least about 40%, more preferably at least about 50%, by weight of the secondary (2,3) alkyl sulfate, the balance comprising the co-surfactant or mixtures of co-surfactants.

Of course, it will be recognized by the formulator that certain types of surfactants tend to be tacky. Other surfactants tend to be hygroscopic, and can thus become tacky when exposed to high humidity. In such instances, the resulting mixed, high-active particles may exhibit sub-optimal flowability. Under such circumstances the formulator may choose to coat the surfaces of the mixed particles with a free-flow promoter, such as finely-divided zeolite powder, or even, as now discovered, with a fine powder of the secondary (2,3) alkyl sulfate.

The formulator will also recognize that with certain co-surfactants the overall solubility of the mixed high-active particles may need additional boosting, especially in very cold water or with high density granules. Under such circumstances, various additional solubilizing agents can be incorporated into the particles, typically at levels in the range of 5%-20% by weight of particles. For example, any highly soluble material can be used for this purpose, and innocuous inorganic salts such as sodium sulfate, sodium bicarbonate, soluble builders as disclosed herein, and the like are typical. The mixed particles herein can comprise, for example: secondary (2,3) alkyl sulfates plus primary C₁₀-C₁₈ alkyl sulfates; secondary (2,3) alkyl sulfates plus alkyl ethoxy carboxylates; secondary (2,3) alkyl sulfates plus polyhydroxy fatty acid amide surfactants described more fully hereinafter; secondary (2,3) alkyl sulfates plus alkyl ethoxy sulfates; secondary (2,3) alkyl sulfates plus primary alkyl sulfates plus polyhydroxy fatty acid amides; secondary (2,3) alkyl sulfates plus alkyl ethoxy sulfates plus polyhydroxy fatty acid amides; secondary (2,3) alkyl sulfates plus primary alkyl sulfates plus alkyl ethoxy sulfates plus polyhydroxy fatty acid amides; secondary (2,3) alkyl sulfates plus α-sulfonated fatty acid methyl esters; secondary (2,3) alkyl sulfates plus C₁₀-C₁₈ alkyl polyglycosides; and secondary (2,3) alkyl sulfates plus α-sulfonated fatty acid methyl esters plus polyhydroxy fatty acid amides. Particles comprising the secondary (2,3) alkyl sulfates plus conventional C₁₀-C₁₈ soaps can also be prepared. The foregoing are intended to be nonlimiting examples of such mixed particles, others of which will readily come to mind with the skilled formulator.

In general terms, particles used herein comprising the secondary (2,3) alkyl sulfate surfactants can be prepared using a variety of well-known processes. For example, particles can be formed by agglomeration, wherein solids (including the secondary (2,3) alkyl sulfates) are forced/hurled together by physical mixing and held together by a binder. Suitable apparatus for agglomeration includes dry powder mixers, fluid beds and turbilizers, available from manufacturers such as Lόdige, Eric, Bepex and Aeromatic.

In another mode, particles can be formed by extrusion. In this method, solids such as the secondary (2,3) alkyl sulfates are forced together by pumping a damp powder at relatively high pressures and high energy inputs through small holes in a die plate. This process results in rod like particles which can be divided into any desired particle size. Apparatus includes axial or radial extruders such as those available from Fuji, Bepex and Teledyne/Readco.

In yet another mode, particles can be formed by prilling. In this method, a liquid mixture containing the desired ingredients (i.e., one of them being secondary (2,3) alkyl sulfate particles) is pumped under high pressure and sprayed into cool air. As the liquid droplets cool they become more solid and thus the particles are formed. The solidification can occur due to the phase change of a molten binder to a solid or through hydration of free moisture into crystalline bound moisture by some hydratable material in the original liquid mixture.

In still another mode, particles can be formed by compaction. This method is similar to tablet formation processes, wherein solids (I.e., secondary [2,3] alkyl sulfate particles) are forced together by compressing the powder feed into a die/mold on rollers or flat sheets.

In another mode, particles can be formed by melt/solidification. In this method, particles are formed by melting the secondary (2,3) alkyl sulfate with any desired additional ingredient and allowing the melt to cool, e.g., in a mold or as droplets.

Binders can optionally be used in the foregoing methods to enhance particle integrity and strength. Water, alone, is an operative binder with secondary (2,3) alkyl sulfates, since it will dissolve some of the secondary (2,3) alkyl sulfate to provide a binding function. Other binders include, for example, starches, polyacrylates, carboxymethylcellulose and the like. Binders are well-known in the particle making literature. If used, binders are typically employed at levels of 0.1%-5% by weight of the finished particles.

As noted above, in one embodiment, fillers such as hydratable and nonhydratable salts, crystalline and glassy solids, various detersive ingredients such as zeolites and the like, can be incorporated in the particles. Such fillers typically comprise up to about 40% by weight of the particles.

Particles prepared in the manner disclosed herein can be subsequently dried or cooled to adjust their strength, physical properties and final moisture content, according to the desires of the formulator.

Particle Formation

One mode for preparing particles comprising the mixtures of the secondary (2,3) alkyl sulfate surfactant and the co-surfactants comprises mixing molten secondary (2,3) alkyl sulfate with one or more molten co-surfactants and forming the resulting solidified melt into particles or prills of any desired size. The desired particle size can be achieved, for example, in blenders, such as that marketed under the trademark OSTER or in large-scale mills, such as that available under the trademark WILEY mill.

In an alternate mode, the melt comprising the mixed surfactant plus co-surfactants can be sprayed through a nozzle to form droplets which, when cooled, provide particles of the desired size.

In another mode, a rotating disc can be used to form droplets of a melt comprising the secondary (2,3) alkyl sulfate and any desired co-surfactants. The droplets are then solidified by cooling and may be passed through appropriate sieves to secure particles of any desired size. In yet another mode, tower prilling can be used to provide particles having a distribution of sizes around a given mean size range.

In yet another mode, a homogeneous melt of the secondary (2,3) alkyl sulfate plus co-surfactants is solidified and comminuted to provide particles. High energy comminution processes such as hammer, rod and ball mills can be used. In a different mode, low energy comminution processes such as grating through sieves of any desired pore size can be employed.

When used as the bulk surfactant ingredient in detergent compositions, the mixed surfactant/co-surfactants particles will typically range in size from about 400 to about 1,600 microns. When used to coat larger particles comprising surfactant/co-surfactant mixtures herein, the secondary (2,3) alkyl sulfate will typically be in a substantially finer size range, typically from about 0.1 to about 5 microns. In any event, any desired size ranges herein can be achieved using standard sieves.

Granulation Equipment

Various means and equipment are available to prepare granular particles and detergent compositions according to the present invention. Current commercial practice in the field employs spray-drying towers to manufacture granular laundry detergents which have a density less than about 550 grams/liter. Accordingly, conventional spray drying can be used as the overall process herein. In the alternative, the formulator can eliminate spray-drying by using mixing, densifying and granulating equipment that is commercially available. The following is a nonlimiting description of such equipment suitable for use herein.

High speed mixer/densifiers can optionally be used in the present process. For example, the device marketed under the trademark "Lodige CB30" Recycler comprises a static cylindrical mixing drum having a central rotating shaft with mixing/cutting blades mounted thereon. In use, the ingredients for the detergent composition are introduced into the drum and the shaft/blade assembly is rotated at speeds in the range of 100-2500 rpm to provide thorough mixing/densification. Other such apparatus includes the devices marketed under the trademark "Shugi Granulator" and under the trademark "Drais K-TTP 80).

Depending on the degree of densification and/or agglomeration desired, a processing step involving further densification can be conducted. Equipment such as that marketed under the trademark "Lόdige KM300 Mixer", also known as the "Lodige Ploughshare" can be used. Such equipment is typically operated at 40-160 rpm. Other useful equipment includes the device which is available under the trademark "Drais K-T 160".

In yet another mode, the granulation process can be conducted using a fluidized bed mixer. In this method, the various ingredients of the finished composition are combined in an aqueous slurry and sprayed into a fluidized bed of particles comprising the secondary (2,3) alkyl sulfate plus co-surfactant to provide the finished detergent granules. In an alternate mode, the slurry can be sprayed into a fluidized bed of zeolite or layered silicate particles, or into a mixture of particles comprising secondary (2,3) alkyl sulfate/co-surfactant plus zeolite and/or layered silicate particles. In such a process, the first step may optionally include mixing of the slurry using a "Lόdige CB30" or "Flexomix 160", available from Shugi. Fluidized bed or moving beds of the type available under the trademark "Escher Wyss can be used in such processes.

Other types of granules manufacturing apparatus useful herein include the apparatus disclosed in U.S. Patent 2,306,898, to G. L. Heller, December 29, 1942. Densification Operating Conditions

It is to be understood that a particular advantage afforded by the invention herein is that the particulate nature of the particles which comprise secondary (2,3) alkyl sulfate plus co-surfactant allows the formulator to choose from a variety of manufacturing equipment and operating conditions to prepare low density, or, preferably, high density, high solubility, free-flowing detergent granules. Such processes provide granules having a bulk density greater than about 550 grams/liter (below which is the range for "low-density" particles), preferably greater than about 650 grams/liter.

In one mode, the compositions herein can be prepared by a combination of a spray-drying step, followed by an admixing/densification step. In this procedure, an aqueous slurry of various heat-stable ingredients in the final detergent composition are formed into homogeneous granules by passage through a spray-dry tower, using conventional techniques. The resulting granules are then admixed with particles of the secondary (2,3) alkyl sulfate plus co-surfactant in a rotary or screw-type mixer/densifier, using a residence time of typically 1-5 minutes at an operating speed of 500-1500 rpm to provide the finished, densified product. In a modification of this method, heat-labile ingredients such as detersive enzymes and bleach activators are added to the composition in the mixer/densifier apparatus.

In another mode, the compositions are prepared and densified by passage through two mixer and densifier machines operating in sequence. Thus, for example, the desired compositional ingredients can be admixed and passed through a Lόdige mixer using residence times of 0.1 to 1.0 minutes then passed through a second Lόdige mixer using residence times of 1 minute to 5 minutes.

In yet another mode, the compositions can be prepared in densified granular form using any of the foregoing methods, followed by admixture with finely-powdered (typically 0.1-10 micrometer) particles comprising either pure secondary (2,3) alkyl sulfate, or mixtures thereof with the co-surfactant. This provides a coating of particulate secondary (2,3) alkyl sulfate on the exterior surfaces of the densified granules, which enhances their flowability and reduces caking. In yet another mode, an aqueous slurry (typically 80% solids content) comprising the desired formulation ingredients is sprayed into a fluidized bed of particulate secondary (2,3) alkyl sulfate plus co-surfactant (typically 400-1,200 micron size). The resulting particles can be further densified by passage through a Lόdige apparatus, as noted above.

Adjunct Ingredients

In addition to the particles comprising secondary (2,3) alkyl sulfates plus co-surfactants, the detergent compositions herein will typically comprise various adjunct ingredients. Nonlimiting examples of such ingredients are as follows.

Enzymes - Enzymes can be included in the detergent formulations herein for a wide variety of fabric laundering purposes, including removal of protein-based, carbohydrate-based, or triglyceride-based stains, to prevent refugee dye transfer, and for fabric restoration. The enzymes to be incorporated include proteases, amylases, Upases, cellulases, and peroxidases, as well as mixtures thereof. Other types of enzymes may also be included. They may be of any suitable origin, such as vegetable, animal, bacterial, fungal and yeast origin. However, their choice is governed by several factors such as pH-activity and/or stability optima, thermostability, stability versus active detergents, builders and so on. In this respect bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases, and fungal cellulases.

Enzymes are normally incorporated at levels sufficient to provide up to about 5 mg by weight, more typically about 0.01 mg to about 3 mg, of active enzyme per gram of the composition. Stated otherwise, the compositions herein will typically comprise from about 0.001% to about 5%, preferably 0.01%-1%, by weight of a commercial enzyme preparation. Protease enzymes are usually present in such commercial preparations at levels sufficient to provide from 0.005 to 0.1 Anson units (AU) of activity per gram of composition.

Suitable examples of proteases are the subtil isins which are obtained from particular strains of B.subtilis and B.licheniforms. Another suitable protease is obtained from a strain of Bacillus, having maximum activity throughout the pH range of 8-12, developed and sold by Novo Industries A/S under the registered trade name ESPERASE. The preparation of this enzyme and analogous enzymes is described in British Patent Specification No. 1,243,784 of Novo. Proteolytic enzymes suitable for removing protein-based stains that are commercially available include those sold under the tradenames ALCALASE and SAVINASE by Novo Industries A/S (Denmark) and MAXATASE by International Bio-Synthetics, Inc. (The Netherlands). Other proteases include Protease A (see European Patent Application 130,756, published January 9, 1985) and Protease B (see European Patent Application Serial No. 87303761.8, filed April 28, 1987, and European Patent Application 130,756, Bott et al, published January 9, 1985).

Amylases Include, for example, α-amylases described in British Patent Specification No. 1,296,839 (Novo), RAPIDASE, International Bio-Synthetics, Inc. and TERMAMYL, Novo Industries.

The cellulases usable in the present invention include both bacterial or fungal cellulase. Preferably, they will have a pH optimum of between 5 and 9.5. Suitable cellulases are disclosed in U.S. Patent 4,435,307, Barbesgoard et al, issued March 6, 1984, which discloses fungal cellulase produced from Humicola insolens and Humicola strain DSM1800 or a cellulase 212-producing fungus belonging to the genus Aeromonas, and cellulase extracted from the hepatopancreas of a marine mollusk (Dolabella Auricula Solander). Suitable cellulases are also disclosed in GB-A-2.075.028; GB-A-2.095.275 and DE-OS-2.247.832.

Suitable lipase enzymes for detergent usage include those produced by microorganisms of the Pseudomonas group, such as Pseudomonas stutzeri ATCC 19.154, as disclosed in British Patent 1,372,034. See also lipases in Japanese Patent Application 53-20487, laid open to public inspection on February 24, 1978. This lipase is available from Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name Lipase P "Amano," hereinafter referred to as "Amano-P." Other commercial lipases include Amano-CES, lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var. l ipolyticum NRRLB 3673, commercially available from Toyo Jozo Co., Tagata, Japan; and further Chromobacter viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands, and lipases ex Pseudomonas gladioli . The LIPOLASE enzyme derived from Humicola lanuginosa and commercially available from Novo (see also EPO 341,947) is a preferred lipase for use herein.

Peroxidase enzymes are used in combination with oxygen sources, e.g., percarbonate, perborate, persulfate, hydrogen peroxide, etc. They are used for "solution bleaching," i.e. to prevent transfer of dyes or pigments removed from substrates during wash operations to other substrates in the wash solution. Peroxidase enzymes are known in the art, and include, for example, horseradish peroxidase, ligninase, and haloperoxidase such as chloro- and bromo-peroxidase. Peroxidase-containing detergent compositions are disclosed, for example, in PCT International Application WO 89/099813, published October 19, 1989, by 0. Kirk, assigned to Novo Industries A/S.

A wide range of enzyme materials and means for their incorporation into synthetic detergent granules is also disclosed in U.S. Patent 3,553,139, issued January 5, 1971 to McCarty et al (). Enzymes are further disclosed in U.S. Patent 4,101,457, Place et al, issued July 18, 1978, and in U.S. Patent 4,507,219, Hughes, issued March 26, 1985, both. Enzyme materials useful for detergent formulations, and their incorporation into such formulations, are disclosed in U.S. Patent 4,261,868, Hora et al, issued April 14, 1981. Enzymes for use in detergents can be stabilized by various techniques. Enzyme stabilization techniques are disclosed and exemplified in U.S. Patent 4,261,868, issued April 14, 1981 to Horn, et al, U.S. Patent 3,600,319, issued August 17, 1971 to Gedge, et al, and European Patent Application Publication No. 0 199405, Application No. 86200586.5, published October 29, 1986, Venegas. Enzyme stabilization systems are also described, for example, in U.S. Patents 4,261,868, 3,600,319, and 3,519,570.

Enzyme Stabilizers - The enzymes employed herein are stabilized by the presence of water-soluble sources of calcium ions in the finished compositions which provide calcium ions to the enzymes. Additional stability can be provided by the presence of various other art-disclosed stabilizers, especially borate species: see Severson, U.S. 4,537,706, cited above. Typical detergents will comprise from about 1 to about 30, preferably from about 2 to about 20, more preferably from about 5 to about 15, and most preferably from about 8 to about 12, millimoles of calcium ion per liter of finished composition. This can vary somewhat, depending on the amount of enzyme present and its response to the calcium ions. The level of calcium ion should be selected so that there is always some minimum level available for the enzyme, after allowing for complexation with builders, fatty acids, etc., in the composition. Any water-soluble calcium salt can be used as the source of calcium ion, including, but not limited to, calcium chloride, calcium sulfate, calcium malate, calcium hydroxide, calcium formate, and calcium acetate. A small amount of calcium ion, generally from about 0.05 to about 0.4 millimoles per liter, is often also present in the composition due to calcium in the enzyme slurry and formula water. Solid detergent compositions according to the present invention may include a sufficient quantity of a water-soluble calcium ion source to provide such amounts in the laundry liquor. In the alternative, natural water hardness may suffice.

It is to be understood that the foregoing levels of calcium ions are sufficient to provide enzyme stability. More calcium ions can be added to the compositions to provide an additional measure of grease removal performance. Accordingly, the compositions herein may comprise from about 0.05% to about 2% by weight of a water-soluble source of calcium ions. The amount can vary, of course, with the amount and type of enzyme employed in the composition.

The compositions herein may also optionally, but preferably, contain various additional stabilizers, especially borate-type stabilizers. Typically, such stabilizers will be used at levels in the compositions from about 0.25% to about 10%, preferably from about 0.5% to about 5%, more preferably from about 0.75% to about 3%, by weight of boric acid or other borate compound capable of forming boric acid in the composition (calculated on the basis of boric acid). Boric acid is preferred, although other compounds such as boric oxide, borax and other alkali metal borates (e.g., sodium ortho-, meta- and pyroborate, and sodium pentaborate) are suitable. Substituted boric acids (e.g., phenylboronic acid, butane boronic acid, and p-bromo phenylboronic acid) can also be used in place of boric acid. In addition to enzymes, the compositions herein can optionally include one or more other detergent adjunct materials or other materials for assisting or enhancing cleaning performance, treatment of the substrate to be cleaned, or to modify the aesthetics of the detergent composition (e.g., perfumes, colorants, dyes, etc.). The following are illustrative examples of such adjunct materials.

Builders - Detergent builders can optionally be included in the compositions herein to assist in controlling mineral hardness. Inorganic as well as organic builders can be used. Builders are typically used in fabric laundering compositions to assist in the removal of particulate soils.

The level of builder can vary widely depending upon the end use of the composition and its desired physical form. When present, the compositions will typically comprise at least about 1% builder. Granular formulations typically comprise from about 10% to about 80%, more typically from about 15% to about 50% by weight, of the detergent builder. Lower or higher levels of builder, however, are not meant to be excluded.

Inorganic detergent builders include, but are not limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphates (exemplified by the tripolyphosphates, pyrophosphates, and glassy polymeric meta-phosphates), phosphonates, phytic acid, silicates, carbonates (including bicarbonates and sesquicarbonates), sulphates, and aluminosilicates. However, non-phosphate builders are required in some locales. Importantly, the compositions herein function surprisingly well even in the presence of the so-called "weak" builders (as compared with phosphates) such as citrate, or in the so-called "underbuilt" situation that may occur with zeolite or layered silicate builders. Moreover, the secondary (2,3) alkyl sulfate plus enzyme components perform best in the presence of weak, nonphosphate builders which allow free calcium ions to be present.

Examples of silicate builders are the alkali metal silicates, particularly those having a SiO₂:Na₂O ratio in the range 1.6:1 to 3.2:1 and layered silicates, such as the layered sodium silicates described in U.S. Patent 4,664,839, issued May 12, 1987 to H. P. Rieck. NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na SKS-6 silicate builder does not contain aluminum. NaSKS-6 has the delta-Na₂SiO₅ morphology form of layered silicate. It can be prepared by methods such as those described in German DE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a highly preferred layered silicate for use herein, but other such layered silicates, such as those having the general formula NaMSi_xO_2x+l·yH₂O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20, preferably 0, can be used. Various other layered silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and gamma forms. As noted above, the delta-Na2S105 (NaSKS-6 form) is most preferred for use herein. Other silicates may also be useful such as for example magnesium silicate, which can serve as a crispening agent in granular formulations, as a stabilizing agent for oxygen bleaches, and as a component of suds control systems.

Examples of carbonate builders are the alkaline earth and alkali metal carbonates as disclosed in German Patent Application No. 2,321,001 published on November 15, 1973.

Aluminosilicate builders are especially useful in the present invention. Aluminosilicate builders are of great importance in most currently marketed heavy duty granular detergent compositions. Aluminosilicate builders include those having the empirical formula:

M_z(zAlO₂·ySiO₂)

wherein M is sodium, potassium, ammonium or substituted ammonium, z is from about 0.5 to about 2; and y is 1; this material having a magnesium ion exchange capacity of at least about 50 milligram equivalents of CaCO₃ hardness per gram of anhydrous aluminosilicate. Preferred aluminosilicates are zeolite builders which have the formula:

Na_z[(AlO₂)_z (SiO₂)_y]-xH₂O

wherein z and y are integers of at least 6, the molar ratio of z to y is in the range from 1.0 to about 0.5, and x is an integer from about 15 to about 264.

Useful aluminosilicate ion exchange materials are commercially available. These aluminosilicates can be crystalline or amorphous in structure and can be naturally-occurring aluminosilicates or synthetically derived. A method for producing aluminosilicate ion exchange materials is disclosed in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein are available under the designations Zeolite A, Zeolite P (B), and Zeolite X. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange material has the formula:

Na₁₂[(AlO₂)₁₂(SiO₂)₁₂]·xH₂O

wherein x is from about 20 to about 30, especially about 27. This material is known as Zeolite A. Preferably, the aluminosilicate has a particle size of about 0.1-10 microns in diameter.

Organic detergent builders suitable for the purposes of the present invention include, but are not restricted to, a wide variety of polycarboxylate compounds. As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably at least 3 carboxylates. Polycarboxylate builder can generally be added to the composition in acid form, but can also be added in the form of a neutralized salt. When utilized in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammonium salts are preferred.

Included among the polycarboxylate builders are a variety of categories of useful materials. One important category of polycarboxylate builders encompasses the ether polycarboxylates, including oxydisuccinate, as disclosed in Berg, U.S. Patent 3,128,287, issued April 7, 1964, and Lamberti et al, U.S. Patent 3,635,830, issued January 18, 1972. See also "TMS/TDS" builders of U.S. Patent 4,663,071, issued to Bush et al, on May 5, 1987. Suitable ether polycarboxylates also include cyclic compounds, particularly alicyclic compounds, such as those described in U.S.

Patents 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903.

Other useful detergency builders include the ether hydroxypolycarboxylates, copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxy benzene-2, 4, 6-trisulphonic acid, and carboxymethyloxysuccinic acid, the various alkali metal, ammonium and substituted ammonium salts of polyacetic acids such as ethylenediamine tetraacetic acid and nitrilotriacetic acid, as well as polycarboxylates such as mellitic acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid, carboxymethyloxysuccinic acid, and soluble salts thereof.

Citrate builders, e.g., citric acid and soluble salts thereof (particularly sodium salt), are polycarboxylate builders of particular importance for heavy duty detergent formulations due to their availability from renewable resources and their biodegradability. Citrates can also be used in granular compositions, especially in combination with zeolite and/or layered silicate builders. Oxydisuccinates are also especially useful in such compositions and combinations.

Also suitable in the detergent compositions of the present invention are the 3,3-dicarboxy-4-oxa-1,6-hexanedioates and the related compounds disclosed in U.S. Patent 4,566,984, Bush, issued January 28, 1986. Useful succinic acid builders include the C₅-C₂₀ alkyl and alkenyl succinic acids and salts thereof. A particularly preferred compound of this type is dodecenylsuccinic acid. Specific examples of succinate builders include: laurylsuccinate, myristylsuccinate, palmitylsuccinate, 2-dodecenyl succinate (preferred), 2-pentadecenylsuccinate, and the like. Laurylsuccinates are the preferred builders of this group, and are described in European Patent Application 86200690.5/0,200,263, published November 5, 1986.

Other suitable polycarboxylates are disclosed in U.S. Patent 4,144,226, Crutchfield et al, issued March 13, 1979 and in U.S. Patent 3,308,067, Diehl, issued March 7, 1967. See also Diehl U.S. Patent 3,723,322.

Fatty acids, e.g., C₁₂-C₁₈ monocarboxylic acids, can also be incorporated into the compositions alone, or in combination with the aforesaid builders, especially citrate and/or the succinate builders, to provide additional builder activity. Such use of fatty acids will generally result in a diminution of sudsing, which should be taken into account by the formulator.

In situations where phosphorus-based builders can be used, the various alkali metal phosphates such as the well-known sodium tripolyphosphates, sodium pyrophosphate and sodium orthophosphate can be used. Phosphonate builders such as ethane-1-hydroxy-1,1-diphosphonate and other known phosphonates (see, for example, U.S. Patents 3,159,581; 3,213,030; 3,422,021; 3,400,148 and 3,422,137) can also be used.

Bleaching Compounds - Bleaching Agents and Bleach Activators - The detergent compositions herein may optionally contain bleaching agents or bleaching compositions containing a bleaching agent and one or more bleach activators. When present, bleaching agents will typically be at levels of from about 1% to about 30%, more typically from about 5% to about 20%, of the detergent composition, especially for fabric laundering. If present, the amount of bleach activators will typically be from about 0.1% to about 60%, more typically from about 0.5% to about 40% of the bleaching composition comprising the bleaching agent-plus-bleach activator.

The bleaching agents used herein can be any of the bleaching agents useful for detergent compositions in textile cleaning, hard surface cleaning, or other cleaning purposes that are now known or become known. These include oxygen bleaches as well as other bleaching agents. Perborate bleaches, e.g., sodium perborate (e.g., mono- or tetra-hydrate) can be used herein.

One category of bleaching agent that can be used without restriction encompasses percarboxylic acid bleaching agents and salts thereof. Suitable examples of this class of agents include magnesium monoperoxyphthalate hexahydrate, the magnesium salt of meta-chloro perbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid and diperoxydodecanedioic acid. Such bleaching agents are disclosed in U.S. Patent 4,483,781, Hartman, issued November 20, 1984, U.S. Patent Application 740,446, Burns et al, filed June 3, 1985, European Patent Application 0,133,354, Banks et al, published February 20, 1985, and U.S. Patent 4,412,934, Chung et al, issued November 1, 1983. Highly preferred bleaching agents also include 6-nonylamino-6-oxoperoxycaproic acid as described in U.S. Patent 4,634,551, issued January 6, 1987 to Burns et al.

Peroxygen bleaching agents can also be used. Suitable peroxygen bleaching compounds include sodium carbonate peroxyhydrate and equivalent "percarbonate" bleaches, sodium pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Persulfate bleach (e.g., OXONE, manufactured commercially by DuPont) can also be used.

Mixtures of bleaching agents can also be used.

Peroxygen bleaching agents, the perborates, the percarbonates, etc. are preferably combined with bleach activators, which lead to the in situ production in aqueous solution (i.e., during the washing process) of the peroxy acid corresponding to the bleach activator. Various nonlimiting examples of activators are disclosed in U.S. Patent 4,915,854, issued April 10, 1990 to Mao et al, and U.S. Patent 4,412,934. The nonanoyloxybenzene sulfonate (NOBS) and tetraacetyl ethylene diamine (TAED) activators are typical, and mixtures thereof can also be used. See also U.S. 4,634,551 for other typical bleaches and activators useful herein.

Bleaching agents other than oxygen bleaching agents are also known in the art and can be utilized herein. One type of nonoxygen bleaching agent of particular interest includes photoactivated bleaching agents such as the sulfonated zinc and/or aluminum phthalocyanines. See U.S. Patent 4,033,718, issued July 5, 1977 to Holcombe et al. If used, detergent compositions will typically contain about 0.025% to about 1.25%, by weight, of such bleaches, especially sulfonated zinc phthalocyanine.

Polymeric Soil Release Agent - Any polymeric soil release agent known to those skilled in the art can optionally be employed in the compositions and processes of this invention. Polymeric soil release agents are characterized by having both hydrophilic segments, to hydrophilize the surface of hydrophobic fibers, such as polyester and nylon, and hydrophobic segments, to deposit upon hydrophobic fibers and remain adhered thereto through completion of washing and rinsing cycles and, thus, serve as an anchor for the hydrophilic segments. This can enable stains occurring subsequent to treatment with the soil release agent to be more easily cleaned in later washing procedures.

The polymeric soil release agents useful herein especially include those soil release agents having: (a) one or more nonionic hydrophile components consisting essentially of (i) polyoxyethylene segments with a degree of polymerization of at least 2, or (ii) oxypropylene or polyoxypropylene segments with a degree of polymerization of from 2 to 10, wherein said hydrophile segment does not encompass any oxypropylene unit unless it is bonded to adjacent moieties at each end by ether linkages, or (iii) a mixture of oxyalkylene units comprising oxyethylene and from 1 to about 30 oxypropylene units wherein said mixture contains a sufficient amount of oxyethylene units such that the hydrophile component has. hydrophilicity great enough to increase the hydrophilicity of conventional polyester synthetic fiber surfaces upon deposit of the soil release agent on such surface, said hydrophile segments preferably comprising at least about 25% oxyethylene units and more preferably, especially for such components having about 20 to 30 oxypropylene units, at least about 50% oxyethylene units; or (b) one or more hydrophobe components comprising (i) C₃ oxyalkylene terephthalate segments, wherein, if said hydrophobe components also comprise oxyethylene terephthalate, the ratio of oxyethylene terephthalate:C₃ oxyalkylene terephthalate units is about 2:1 or lower, (ii) C₄-C₆ alkylene or oxy C₄-C₆ alkylene segments, or mixtures therein, (iii) poly (vinyl ester) segments, preferably poly(vinyl acetate), having a degree of polymerization of at least 2, or (iv) C₁-C₄ alkyl ether or C₄ hydroxyalkyl ether substituents, or mixtures therein, wherein said substituents are present in the form of C₁-C₄ alkyl ether or C₄ hydroxyalkyl ether cellulose derivatives, or mixtures therein, and such cellulose derivatives are amphiphilic, whereby they have a sufficient level of C₁-C₄ alkyl ether and/or C₄ hydroxyalkyl ether units to deposit upon conventional polyester synthetic fiber surfaces and retain a sufficient level of hydroxyls, once adhered to such conventional synthetic fiber surface, to increase fiber surface hydrophilicity, or a combination of (a) and (b).

Typically, the polyoxyethylene segments of (a)(i) will have a degree of polymerization of from 2 to about 200, although higher levels can be used, preferably from 3 to about 150, more preferably from 6 to about 100. Suitable oxy C₄-C₆ alkylene hydrophobe segments include, but are not limited to, end-caps of polymeric soil release agents such as MO₃S(CH₂)_nOCH₂CH₂O-, where M is sodium and n is an integer from 4-6, as disclosed in U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink. Polymeric soil release agents useful in the present invention also include cellulosic derivatives such as hydroxyether cellulosic polymers, copolymeric blocks of ethylene terephthalate or propylene terephthalate with polyethylene oxide or polypropylene oxide terephthalate, and the like. Such agents are commercially available and include hydroxyethers of cellulose such as METHOCEL (Dow). Cellulosic soil release agents for use herein also include those selected from the group consisting of C₁-C₄ alkyl and C₄ hydroxyalkyl cellulose; see U.S. Patent 4,000,093, issued December 28, 1976 to Nicol, et al.

Soil release agents characterized by poly(vinyl ester) hydrophobe segments include graft copolymers of poly(vinyl ester), e.g., C₁-C₆ vinyl esters, preferably poly(vinyl acetate) grafted onto polyalkylene oxide backbones, such as polyethylene oxide backbones. See European Patent Application 0 219 048, published April 22, 1987 by Kud, et al. Commercially available soil release agents of this kind include the SOKALAN type of material, e.g., SOKALAN HP-22, available from BASF (West Germany).

One type of preferred soil release agent is a copolymer having random blocks of ethylene terephthalate and polyethylene oxide (PEO) terephthalate. The molecular weight of this polymeric soil release agent is in the range of from about 25,000 to about 55,000. See U.S. Patent 3,959,230 to Hays, issued May 25, 1976 and U.S. Patent 3,893,929 to Basadur issued July 8, 1975.

Another preferred polymeric soil release agent is a polyester with repeat units of ethylene terephthalate units containing 10-15% by weight of ethylene terephthalate units together with 90-80% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight 300-5,000. Examples of this polymer include the commercially available material ZELCON 5126 (from Dupont) and MILEASE T (from ICI). See also U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.

Another preferred polymeric soil release agent is a sulfonated product of a substantially linear ester oligomer comprised of an oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and terminal moieties covalently attached to the backbone. These soil release agents are described fully in U.S. Patent 4,968,451, issued November 6, 1990 to J. J. Scheibel and E. P. Gosselink.

Other suitable polymeric soil release agents include the terephthalate polyesters of U.S. Patent 4,711,730, issued December 8, 1987 to Gosselink et al, the anionic end-capped oligomeric esters of U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink, and the block polyester oligomeric compounds of U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.

Preferred polymeric soil release agents also include the soil release agents of U.S. Patent 4,877,896, issued October 31, 1989 to Maldonado et al, which discloses anionic, especially sulfoaroyl, end-capped terephthalate esters.

If utilized, soil release agents will generally comprise from about 0.01% to about 10.0%, by weight, of the detergent compositions herein, typically from about 0.1% to about 5%, preferably from about 0.2% to about 3.0%.

Chelating Agents - The detergent compositions herein may also optionally contain one or more iron and/or manganese chelating agents. Such chelating agents can be selected from the group consisting of amino carboxylates, amino phosphonates, polyfunctionally-substituted aromatic chelating agents and mixtures therein, all as hereinafter defined. Without intending to be bound by theory, it is believed that the benefit of these materials is due in part to their exceptional ability to remove iron and manganese ions from washing solutions by formation of soluble chelates.

Amino carboxylates useful as optional chelating agents include ethylenediaminetetraacetates, N-hydroxyethylethylenedi-aminetriacetates, nitrilotriacetates, ethylenediamine tetraproprionates, triethylenetetraaminehexaacetates, diethylenetriamine-pentaacetates, and ethanoldiglycines, alkali metal, ammonium, and substituted ammonium salts therein and mixtures therein.

Amino phosphonates are also suitable for use as chelating agents in the compositions of the invention when at least low levels of total phosphorus are permitted in detergent compositions, and include ethylenediaminetetrakis (methylenephosphonates), nitrilotris (methylenephosphonates) and diethylenetriaminepentakis (methylenephosphonates) as DEQUEST. Preferably, these amino phosphonates do not contain alkyl or alkenyl groups with more than about 6 carbon atoms.

Polyfunctionally-substituted aromatic chelating agents are also useful in the compositions herein. See U.S. Patent 3,812,044, issued May 21, 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy -3,5-disulfobenzene.

A preferred biodegradable chelator for use herein is ethyl-enediamine disuccinate ("EDDS"), as described in U.S. Patent 4,704,233, November 3, 1987, to Hartman and Perkins.

If utilized, these chelating agents will generally comprise from about 0.1% to about 10% by weight of the detergent compositions herein. More preferably, if utilized, the chelating agents will comprise from about 0.1% to about 3.0% by weight of such compositions.

Clav Soil Removal/Anti-redeposition Agents - The compositions of the present invention can also optionally contain water-soluble ethoxylated amines having clay soil removal and anti-redeposition properties. Granular detergent compositions which contain these compounds typically contain from about 0.01% to about 10.0% by weight of the water-soluble ethoxylated amines.

The most preferred soil release and anti-redeposition agent is ethoxylated tetraethylenepentamine. Exemplary ethoxylated amines are further described in U.S. Patent 4,597,898, VanderMeer, issued July 1, 1986. Another group of preferred clay soil removal/antiredeposition agents are the cationic compounds disclosed in European Patent Application 111,965, Oh and Gosselink, published June 27, 1984. Other clay soil removal/antiredeposition agents which can be used include the ethoxylated amine polymers disclosed in European Patent Application 111,984, Gosselink, published June 27, 1984; the zwitterionic polymers disclosed in European Patent Application 112,592, Gosselink, published July 4, 1984; and the amine oxides disclosed in U.S. Patent 4,548,744, Connor, issued October 22, 1985. Other clay soil removal and/or anti redeposition agents known in the art can also be utilized in the compositions herein. Another type of preferred anti-redeposition agent includes the carboxy methyl cellulose (CMC) materials. These materials are well known in the art. Polymeric Dispersing Agents - Polymeric dispersing agents can advantageously be utilized at levels from about 0.1% to about 7%, by weight, in the compositions herein, especially in the presence of zeolite and/or layered silicate builders. Suitable polymeric dispersing agents include polymeric polycarboxylates and polyethylene glycol s, although others known in the art can also be used. It is believed, though it is not intended to be limited by theory, that polymeric dispersing agents enhance overall detergent builder performance, when used in combination with other builders (including lower molecular weight polycarboxylates) by crystal growth inhibition, particulate soil release peptization, and anti -redeposition.

Polymeric polycarboxylate materials can be prepared by polymerizing or copolymerizing suitable unsaturated monomers, preferably in their acid form. Unsaturated monomeric acids that can be polymerized to form suitable polymeric polycarboxylates include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid and methylenemalonic acid. The presence in the polymeric polycarboxylates herein of monomeric segments, containing no carboxylate radicals such as vinylmethyl ether, styrene, ethylene, etc. is suitable provided that such segments do not constitute more than about 40% by weight.

Particularly suitable polymeric polycarboxylates can be derived from acrylic acid. Such acrylic acid-based polymers which are useful herein are the water-soluble salts of polymerized acrylic acid. The average molecular weight of such polymers in the acid form preferably ranges from about 2,000 to 10,000, more preferably from about 4,000 to 7,000 and most preferably from about 4,000 to 5,000. Water-soluble salts of such acrylic acid polymers can include, for example, the alkali metal, ammonium and substituted ammonium salts. Soluble polymers of this type are known materials. Use of polyacrylates of this type in detergent compositions has been disclosed, for example, in Diehl, U.S. Patent 3,308,067, issued March 7, 1967.

Acrylic/maleic-based copolymers may also be used as a preferred component of the dispersing/anti-redeposition agent. Such materials include the water-soluble salts of copolymers of acrylic acid and maleic acid. The average molecular weight of such copolymers in the acid form preferably ranges from about 2,000 to 100,000, more preferably from about 5,000 to 75,000, most preferably from about 7,000 to 65,000. The ratio of acrylate to maleate segments in such copolymers will generally range from about 30:1 to about 1:1, more preferably from about 10:1 to 2:1. Water-soluble salts of such acrylic acid/maleic acid copolymers can include, for example, the alkali metal, ammonium and substituted ammonium salts. Soluble acryl ate/maleate copolymers of this type are known materials which are described in European Patent Application No. 66915, published December 15, 1982.

Another polymeric material which can be included is polyethylene glycol (PEG). PEG can exhibit dispersing agent performance as well as act as a clay soil removal/antiredeposition agent. Typical molecular weight ranges for these purposes range from about 500 to about 100,000, preferably from about 1,000 to about 50,000, more preferably from about 1,500 to about 10,000.

Polyaspartate and polyglutamate dispersing agents may also be used, especially in conjunction with zeolite builders.

Brightener - Any optical brighteners or other brightening or whitening agents known in the art can be incorporated at levels typically from about 0.05% to about 1.2%, by weight, into the detergent compositions herein. Commercial optical brighteners which may be useful in the present invention can be classified into subgroups which include, but are not necessarily limited to, derivatives of stilbene, pyrazoline, coumarin, carboxylic acid, methinecyanines, dibenzothiphene-5,5-dioxide, azoles, 5- and 6-membered-ring heterocycles, and other miscellaneous agents. Examples of such brighteners are disclosed in "The Production and Application of Fluorescent Brightening Agents", M. Zahradnik, Published by John Wiley & Sons, New York (1982).

Specific examples of optical brighteners which are useful in the present compositions are those identified in U.S. Patent 4,790,856, issued to Wixon on December 13, 1988. These brighteners include the PHORWHITE series of brighteners from Verona. Other brighteners disclosed in this reference include: Tinopal UNPA, Tinopal CBS and Tinopal 5BM; available from Ciba-Geigy; Arctic White CC and Artie White CWD, available from Hilton-Davis, located in Italy; the 2-(4-styryl-phenyl)-2H- naphthol[1,2-d]-triazoles; 4,4'-bis- (1,2,3-triazol-2-yl)-stil- benes; 4,4'-bis-(styryl)bisphenyls; and the aminocoumarins. Specific examples of these brighteners include 4-methyl-7-diethyl- amino coumarin; 1,2-bis(-benzimidazol-2-yl)ethylene; 1,3-diphenylphrazolines; 2,5-bis(benzoxazol-2-yl)thiophene; 2-styryl-naphth-[1,2-d]oxazole; and 2-(stilbene-4-yl)-2H-naphtho- [1,2-d]triazole. See also U.S. Patent 3,646,015, issued February 29, 1972 to Hamilton.

Suds Suppressors - Compounds for reducing or suppressing the formation of suds can be incorporated into the compositions of the present invention. Suds suppression can be of particular importance under conditions such as those found in European-style front loading laundry washing machines, or in the concentrated detergency process of U.S. Patents 4,489,455 and 4,489,574, or when the detergent compositions herein optionally include a relatively high sudsing adjunct surfactant.

A wide variety of materials may be used as suds suppressors, and suds suppressors are well known to those skilled in the art. See, for example, Kirk Othmer Encyclopedia of Chemical Technology, Third Edition, Volume 7, pages 430-447 (John Wiley & Sons, Inc., 1979). One category of suds suppressor of particular interest encompasses monocarboxylic fatty acids and soluble salts therein. See U.S. Patent 2,954,347, issued September 27, 1960 to Wayne St. John. The monocarboxylic fatty acids and salts thereof used as suds suppressor typically have hydrocarbyl chains of 10 to about 24 carbon atoms, preferably 12 to 18 carbon atoms. Suitable salts include the alkali metal salts such as sodium, potassium, and lithium salts, and ammonium and alkanol ammonium salts.

The detergent compositions herein may also contain non-surfactant suds suppressors. These include, for example: high molecular weight hydrocarbons such as paraffin, fatty acid esters (e.g., fatty acid triglycerides), fatty acid esters of monovalent alcohols, aliphatic C₁₈-C₄₀ ketones (e.g. stearone), etc. Other suds inhibitors include N-alkylated amino triazines such as trito hexa-alkylmelamines or di- to tetra-alkyldiamine chlortriazines formed as products of cyanuric chloride with two or three moles of a primary or secondary amine containing 1 to 24 carbon atoms, propylene oxide, and monostearyl phosphates such as monostearyl alcohol phosphate ester and monostearyl di-alkali metal (e.g. K, Na, and Li) phosphates and phosphate esters. The hydrocarbons such as paraffin and haloparaffin can be utilized in liquid form. The liquid hydrocarbons will be liquid at room temperature and atmospheric pressure, and will have a pour point in the range of about -40ºC and about 5ºC, and a minimum boiling point not less than about 110ºC (atmospheric pressure). It is also known to utilize waxy hydrocarbons, preferrably having a melting point below about 110ºC. The hydrocarbons constitute a preferred category of suds suppressor for detergent compositions. Hydrocarbon suds suppressors are described, for example, in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al. The hydrocarbons, thus, include aliphatic, alicyclic, aromatic, and heterocyclic saturated or unsaturated hydrocarbons having from about 12 to about 70 carbon atoms. The term "paraffin," as used in this suds suppressor discussion, is intended to include mixtures of true paraffins and cyclic hydrocarbons.

Another preferred category of non-surfactant suds suppressors comprises silicone suds suppressors. This category includes the use of polyorganosiloxane oils, such as polydimethylsiloxane, dispersions or emulsions of polyorganosiloxane oils or resins, and combinations of polyorganosiloxane with silica particles wherein the polyorganosiloxane is chemisorbed of fused onto the silica. Silicone suds suppressors are well known in the art and are, for example, disclosed in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al and European Patent Application No. 89307851.9, published February 7, 1990, by Starch, M. S.

Other silicone suds suppressors are disclosed in U.S. Patent 3,455,839 which relates to compositions and processes for defoaming aqueous solutions by incorporating therein small amounts of polydimethylsiloxane fluids.

Mixtures of silicone and silanated silica are described, for instance, in German Patent Application DOS 2,124,526. Silicone defoamers and suds controlling agents in granular detergent compositions are disclosed in U.S. Patent 3,933,672, Bartolotta et al, and in U.S. Patent 4,652,392, Baginski et al, issued March 24, 1987. An exemplary silicone based suds suppressor for use herein is a suds suppressing amount of a suds controlling agent consisting essentially of:

(i) polydimethylsiloxane fluid having a viscosity of from about 20 cs. to about 1500 cs. at 25ºC;

(ii) from about 5 to about 50 parts per 100 parts by weight of (i) of siloxane resin composed of (CH₃)₃ SiO_1/2 units of Siθ2 units in a ratio of from (CH₃)₃ SiO_1/2 units and to Siθ2 units of from about 0.6:1 to about 1.2:1; and (iii) from about 1 to about 20 parts per 100 parts by weight of (i) of a solid silica gel;

In the preferred silicone suds suppressor used herein, the solvent for a continuous phase is made up of certain polyethylene glycols or polyethylene-polypropylene glycol copolymers or mixtures thereof (preferred), and not polypropylene glycol. The primary silicone suds suppressor is branched/crossl inked and not linear.

To illustrate this point further, typical laundry detergent compositions with controlled suds will optionally comprise from about 0.001 to about 1, preferably from about 0.01 to about 0.7, most preferably from abut 0.05 to about 0.5, weight % of said silicone suds suppressor, which comprises (1) a nonaqueous emulsion of a primary antifoam agent which is a mixture of (a) a polyorganosiloxane, (b) a resinous siloxane or a silicone resin-producing silicone compound, (c) a finely divided filler material, and (d) a catalyst to promote the reaction of mixture components (a), (b) and (c), to form silanolates; (2) at least one nonionic silicone surfactant; and (3) polyethylene glycol or a copolymer of polyethylene-polypropylene glycol having a solubility in water at room temperature of more than about 2 weight %; and without polypropylene glycol. Similar amounts can be used in granular compositions, gels, etc. See also U.S. Patents

4,978,471, Starch, issued December 18, 1990, and 4 , 983,316,

Starch, issued January 8, 1991 , and U.S. Patents 4,639,489 and 4,749.740, Aizawa et al at column 1, line 46 through column 4, line 35. The silicone suds suppressor herein preferably comprises polyethylene glycol and a copolymer of polyethylene glycol/polypropylene glycol, all having an average molecular weight of less than about 1,000, preferably between about 100 and 800. The polyethylene glycol and polyethylene/polypropylene copolymers herein have a solubility in water at room temperature of more than about 2 weight %, preferably more than about 5 weight %.

The preferred solvent herein is polyethylene glycol having an average molecular weight of less than about 1,000, more preferably between about 100 and 800, most preferably between 200 and 400, and a copolymer of polyethylene glycol/polypropylene glycol, preferably PPG 200/PEG 300. Preferred is a weight ratio of between about 1:1 and 1:10, most preferably between 1:3 and 1:6, of polyethylene glycol:copolymer of polyethylene-polypropylene glycol.

The preferred silicone suds suppressors used herein do not contain polypropylene glycol, particularly of 4,000 molecular weight. They also preferably do not contain block copolymers of ethylene oxide and propylene oxide, like PLURONIC L101.

Other suds suppressors useful herein comprise the secondary alcohols (e.g., 2-alkyl alkanols) and mixtures of such alcohols with silicone oils, such as the silicones disclosed in U.S. 4,798,679, 4,075,118 and EP 150,872. The secondary alcohols include the C₆-C₁₆ alkyl alcohols having a C₁-C₁₆ chain. A preferred alcohol is 2-butyl octanol, which is available from Condea under the trademark ISOFOL 12. Mixtures of secondary alcohols are available under the trademark ISALCHEM 123 from Enichem. Mixed suds suppressors typically comprise mixtures of alcohol + silicone at a weight ratio of 1:5 to 5:1.

For any detergent compositions to be used in automatic laundry washing machines, suds should not form to the extent that they overflow the washing machine. Suds suppressors, when utilized, are preferably present in a "suds suppressing amount." By "suds suppressing amount" is meant that the formulator of the composition can select an amount of this suds controlling agent that will sufficiently control the suds to result in a low-sudsing laundry detergent for use in automatic laundry washing machines. The compositions herein will generally comprise from 0% to about 5% of suds suppressor. When utilized as suds suppressors, monocarboxylic fatty acids, and salts therein, will be present typically in amounts up to about 5%, by weight, of the detergent composition. Preferably, from about 0.5% to about 3% of fatty monocarboxyl ate suds suppressor is utilized. Silicone suds suppressors are typically utilized in amounts up to about 2.0%, by weight, of the detergent composition, although higher amounts may be used. This upper limit is practical in nature, due primarly to concern with keeping costs minimized and effectiveness of lower amounts for effectively controlling sudsing. Preferably from about 0.01% to about 1% of silicone suds suppressor is used, more preferably from about 0.25% to about 0.5%. As used herein, these weight percentage values include any silica that may be utilized in combination with polyorganosiloxane, as well as any adjunct materials that may be utilized. Monostearyl phosphate suds suppressors are generally utilized in amounts ranging from about 0.1% to about 2%, by weight, of the composition. Hydrocarbon suds suppressors are typically utilized in amounts ranging from about 0.01% to about 5.0%, although higher levels can be used. The alcohol suds suppressors are typically used at 0.2%-3% by weight of the finished compositions.

In addition to the foregoing ingredients , the surfactant compositions herein can also be used with a variety of other adjunct ingredients which provide still other benefits in various compositions within the scope of this invention. The following illustrates a variety of such adjunct ingredients, but is not intended to be limiting therein.

Fabric Softeners - Various through-the-wash fabric softeners, especially the impalpable smectite clays of U.S. Patent 4,062,647, Storm and Nirschl, issued December 13, 1977, as well as other softener clays known in the art, can optionally be used typically at levels of from about 0.5% to about 10% by weight in the present compositions to provide fabric softener benefits concurrently with fabric cleaning. Clay softeners can be used in combination with amine and cationic softeners, as disclosed, for example, in U.S. Patent 4,375,416, Crisp et al, March 1, 1983 and U.S. Patent 4,291,071, Harris et al, issued September 22, 1981. Other Ingredients - A wide variety of other ingredients useful in detergent compositions can be included in the compositions herein, including other active ingredients, carriers, processing aids, dyes or pigments. If high sudsing is desired, suds boosters such as the C₁₀-C₁₆ alkanolamides can be incorporated into the compositions, typically at 1%-10% levels. The C₁₀-C₁₄ monoethanol and diethanol amides illustrate a typical class of such suds boosters. Use of such suds boosters with high sudsing adjunct surfactants such as the amine oxides, betaines and sultaines noted above is also advantageous. If desired, soluble magnesium salts such as MgCl₂, MgSO₄, and the like, can be added at levels of, typically, 0.1%-2%, to provide additional sudsing.

Various detersive ingredients employed in the present compositions optionally can be further stabilized by absorbing said ingredients onto a porous hydrophobic substrate, then coating said substrate with a hydrophobic coating. Preferably, the detersive ingredient is admixed with a surfactant before being absorbed into the porous substrate. In use, the detersive ingredient is released from the substrate into the aqueous washing liquor, where it performs its intended detersive function.

To illustrate this technique in more detail, a porous hydrophobic silica (trademark SIPERNAT D10, DeGussa) is admixed with a proteolytic enzyme solution containing 3%-5% of C_13-15 ethoxylated alcohol EO(7) nonionic surfactant. Typically, the enzyme/surfactant solution is 2.5 X the weight of silica. The resulting powder is dispersed with stirring in silicone oil (various silicone oil viscosities in the range of 500-12,500 can be used). The resulting silicone oil dispersion is emulsified or otherwise added to the final detergent matrix. By this means, ingredients such as the aforementioned enzymes, bleaches, bleach activators, bleach catalysts, photoactivators, dyes, fluorescers, fabric conditioners and hydrolyzable surfactants can be "protected" for use in detergents.

Water-soluble particles prepared in the manner of this invention include the following.. EXAMPLE I

High-active, highly water-soluble detergent particles are prepared by co-melting the following ingredients and comminuting the solidified melt.

Ingredient % (wt)

C₁₆ SAS 80

C₁₆ primary alkyl sulfate 6

C_14-16 N-methyl glucamide 10

C_12-14 alcohol ethoxylate (EO5) 4

EXAMPLE II

High-active, highly water-soluble detergent particles are prepared by agglomerating the following ingredients. The free moisture content is kept below about 10%.

Ingredient % (wt)

C_14-16 SAS 20

C_14-16 N-methyl glucamide 10

C₁₆ primary alkyl sulfate 10

Zeolite A (1-10 micron) 40

SKS-6 15

Silica* and minors Balance

*The silica (1 micron) is dusted onto the outside of the particles as a free-flow aid.

The fully-formulated detergent compositions herein will preferably be prepared using the mixed surfactant/co-surfactant particles and adjunct ingredients such that, during use in aqueous cleaning operations, the wash water will have a pH of between about 6.5 and about 11, preferably between about 7.5 and about 10.5. Techniques for controlling pH at recommended usage levels include the use of buffers, alkalis, acids, etc., and are well known to those skilled in the art.

The following are typical, nonlimiting examples which illustrate the uses of the secondary (2,3) alkyl sulfates according to this invention to prepare detergent compositions.

A preferred overall making process for particulate products herein involves three distinct Steps: (1) agglomeration of the ingredients to form the common base formula, followed by; (2) admixing various ingredients with the agglomerates formed in Step

(1) (e.g., percarbonate bleach, bleach activators, and the like); and optionally, but preferably, (3) spraying materials such as perfume onto the final mix.

The base formula is agglomerated as opposed to spray dried in order to prevent degradation of some of the heat sensitive surfactants. The resulting product is a high density (ranging from 600 g/liter - 800 g/liter) free flowing detergent mix that can be used in place of current spray dried laundry detergents.

With regard to the base Agglomeration (Step 1, above), this procedure is comprised of four Steps:

(A) preparing a surfactant paste using mixers such as the

Readco Standard Sigma Mixer, T-Series;

(B) agglomerating powder components with the surfactant paste using mixers such as the Eirich Mixer, R-Series;

(C) drying the agglomerates, such as in a batch-type Aeromatic fluidized bed or a continuous type static or vibrating fluidized bed (NIRO, Bepex or Carrier Companies); and

(D) coating the agglomerates using a mixer such as an Eirich Mixer, R-Series.

The following describes the Agglomeration Step in more detail.

Step A - Preparation of Surfactant Paste - The objective is to combine the surfactants and liquids in the compositions into a common mix in order to aid in surfactant solubilization and agglomeration. In this Step, the surfactants are prepared as mixed particles. The other liquid components in the composition are mixed therewith in a Sigma Mixer at 140ºF (60ºC) at about 40 rpm to about 75 rpm for a period of from 15 minutes to about 30 minutes to provide a paste having the general consistency of 20,000-40,000 centipoise. Once thoroughly mixed, the paste is stored at 140ºF (60ºC) until agglomeration Step (B) is ready to be conducted. The ingredients used in this Step include the mixture of secondary (2,3) alkyl sulfate surfactant plus co-surfactant, acrylate/maleic polymer (m.w. 70,000) and polyethylene glycol "PEG" 4000-8000.

Step B - Agglomeration of Powders with Surfactant Paste - The purpose of this Step is to transform the base formula ingredients into flowable detergent particles having a medium particle size range of from about 300 microns to about 600 microns. In this Step, the powders (including materials such as zeolite, citrate, citric acid builder, layered silicate builder (as SKS-6), sodium carbonate, ethylenediaminedisuccinate, magnesium sulfate and optical brightener) are charged into the Eirich Mixer (R-Series) and mixed briefly {ca. 5 seconds - 10 seconds) at about 1500 rpm to about 3000 rpm in order to mix the various dry powders fully. The surfactant paste from Step A is then charged into the mixer and the mixing is continued at about 1500 rpm to about 3000 rpm for a period from about 1 minute to about 10 minutes, preferably 1-3 minutes, at ambient temperature. The mixing is stopped when coarse agglomerates (average particle size 800-1600 microns) are formed.

Step C - The purpose of this Step is to reduce the agglomerates' stickiness by removing/drying moisture and to aid in particle size reduction to the target particle size (in the median particle size range from about 300 to about 600 microns, as measured by sieve analysis). In this Step, the wet agglomerates are charged into a fluidized bed at an air stream temperature of from about 41ºC to about 60ºC and dried to a final moisture content of the particles from about 4% to about 10%.

Step D - Coat Agglomerates and Add Free-Flow Aids - The objective in this Step is to achieve the final target particle size range of from about 300 microns to about 600 microns, and to admix materials which coat the agglomerates, reduce the caking/lumping tendency of the particles and help maintain acceptable flowability. In this Step, the dried agglomerates from Step C are charged into the Eirich Mixer (R-Series) and mixed at a rate of about 1500 rpm to about 3000 rpm while adding 2-6% Zeolite A (median particle size 2-5μm) during the mixing. The mixing is continued until the desired median particle size of from about 1200 to about 400 microns is achieved (typically from about 5 seconds to about 45 seconds). At this point, from about 0.1% to about 1.5% by weight of precipitated silica (average particle size 1-3 microns) is added as a flow aid and the mixing is stopped.

The following illustrates a laundry detergent composition prepared in the foregoing manner. EXAMPLE III

Agglomerate

% (wt.) in % (wt.) in

Mixed Surfactant/Co-Surfactant final product agglomerate

C_14-15 alkyl sulfate, Na 5.8 6.8

C₁₆ secondary (2,3) alkyl sulfate, Na 17.3 20.4

C₁₂-C₁₃ ethoxylated alcohol (E03) 4.7 5.5

C_12-14 N-methylglucamide 4.7 5.5

Acrylate/maleate copolymer 6.2 7.3

Polyethylene glycol (4000) 1.4 1.7

Additional

Aluminosilicate 8.8 10.3

Sodium citrate 1.9 2.2

Citric acid/SKS-6¹ 11.5 13.5

Sodium carbonate 12.2 14.4

EDDS² 0.4 0.5

Mg sulfate 0.4 0.5

Optical brightener 0.1 0.1

Moisture 7.6 8.9

Silica³ 0.4 0.5

Balance (unreacted and Na₂SO₄) 1.6 1.9

Agglomerate total 85.0 100.0

Dry Mix

Percarbonate, Na (400-600 microns) 7.8

NOBS⁴ 5.9

Silicone/PEG antifoam 0.3

Lipolase 0.3

Savinase 0.3

Spray-on

Perfume 0.4

Finished product total 100.0

¹Co-particle of citric acid and layered silicate (2.0 ratio) ²Ethylenediamine disuccinate

³Hydrophobic precipitated silica (trade name SIPERNAT D-11) ⁴Sodium nonanoyloxybenzene sulfonate

EXAMPLE IV

A granular detergent herein comprises the following. Ingredient % (wt )

Secondary (2,3) al kyl sul fate* 10.0

C_{12- 14} primary al kyl sul fate, Na salt 5.0

Zeol ite A ( 1-10 micrometer) 26.0

Sodium citrate 5.0

Sodium carbonate 20.0

Optical brightener 0.1

Detersive enzyme** 1.0

Sodium sulfate 15.0

Water and minors Balance

*C₁₄-C₁₈ average chain length; Na salt. Combined with the primary alkyl sulfate as particles.

**1:1 mixture LIPOLASE/ESPERASE.

EXAMPLE V

Additional examples of particulate laundry detergents with mixed mixed surfactant/co-surfactants especially suitable for use in front-loading washing machines such as those commonly used in Europe are as follows.

A B C

Mixed Surfactant/Co-surfactants % (wt . ) % (wt . ) % (wt . )

C₁₆ secondary (2,3) alkyl sulfate, Na 1 6.92 9.00 7.60

C_16/18 primary alkyl sulfate 2.05 3.00 1 .30

C₁₂-C₁₅ alkyl ethoxy (1-3) sulfate 0.17 0.40 0. 10

C₁₄-C₁₅ alkyl ethoxylate (EO7) 4.02 5.00 1 .30 C₁₆-C₁₈ AE11 alkyl ethoxylate (EO11) 1.10 1.40 1.10

C₁₆-C₁₈ AE25 alkyl ethoxylate (EO25) 0.85 - - 0.66

Dimethylmonoethoxy C_12-14

alkylammonium chloride - - - - 1.40

Builders

Citrate 5.20 10.00 5.00

Zeolite 4A 20.50 37.20 17.90

Carbonate (Na) 15.00 5.50 12.10

Amorphous silicate 2.0 3.00 2.00 3.10

SOKALAN CP5¹ 4.00 4.90 3.20 Carboxymethylcellulose 0.31 0.39 0.20

Bleach

Perborate monohydrate 8.77 - - 5.80

Perborate tetrahydrate 11 .64 - - 7.40 CO₃/SO₄ coated percarbonate - - 12.0 - -

TAED² 5.00 - - 3.40

Zinc phthalocyanine 20 ppm - - 20 ppm

DEQUEST 2060 (Monsanto) 0.36 0.60 0.38 MgSO₄ 0.40 0.40 0.40

LIPOLASE (100,000LU/g) 0.36 0.25 0.15

Savinase (4.0 KNPU) 1.40 1.60 1.40

Cellulase (1000CEVU/g) 0.13 0.13 0.26

Soil release polymer3 0.20 0.20 0.15 Anionic optical brightener 0.19 - - 0.15

Polyvi nyl pyrrol idone - - 0. 15 - -

Bentonite clay - - - - 12.50

Polyethyleneglycol⁴ - - - - 0.30

Glycerol - - - - 0.62 Perfume 0.43 0.43 0.43

Silicone + dispersant (antifoam) 0.49 0.60 0.49

Moi sture, minors - - - - Bal ance - - - -

¹Copolymer acrylic/maleic acid; mol. wt. range 70,000; Na salt.

²Tetraacetylethylenediamine.

3Anionic polyester reaction product of sulfobenzoic acid, terephthalic acid, propane-1,2-diol, ethylene glycol, sulfoisophthalic acid per Maldonado, ibid.

⁴M.W. 4,000,000 range.

While the foregoing examples illustrate the practice of this invention using the secondary (2,3) alkyl sulfate surfactants and other, mainly anionic, adjunct surfactants, such compositions can also optionally contain various adjunct cationic surfactants and mixtures of cationic and nonionic adjunct surfactants. Useful cationics include the C₁₀-C₁₈ alkyl trimethyl ammonium halides, the C₁₀-C₁₈ alkyl dimethyl (C₁-C₆) hydroxyal kylammonium halides,

C₁₀-C₁₈ choline esters, and the like. If used, such cationic surfactants can typically comprise from 1% to 15% by weight of the compositions herein.

Claims (11)

What is claimed is:

1. A surfactant particle which comprises at least 80% by weight of total surfactants, said surfactants comprising a mixture of:

(a) a C₁₀-C₂₀ secondary (2,3) alkyl sulfate surfactant; and

(b) at least 1% by weight of a solubilizing co-surfactant.

2. A particle according to Claim 1 which comprises at least 40% by weight of a C₁₄-C₁₈ secondaιy (2,3) alkyl sulfate surfactant, or mixtures thereof.

3. A panicle according to either of Claims 1 or 2 comprising at least 75% by weight of secondary (2,3) alkyl sul&te.

4. A particle according to any of Claims 1-3 wherein the co-surfactant is selected from a nonionic surfactant, an alkyl ethoxy sulfate, a primary alkyl sulfate, and mixtures thereof

5. A particle according to any of Claims 1-4 wherein the co-surfactant is a nonionic surfactant, which comprises no more than 25% by weight of the surfactant mixture, selected from the group consisting of ethoxylated alcohols, ethoxylated alkyl phenols, polyhydroxy fatty add amides, alkyl polyglycosides and fatty ethanol amides.

6. A particle according to any of Claims 1-5 wherein the moisture content of the surfactants phis co-surfactants is less than 20% by weight during the formulation process.

7. An agglomerated surfactant particle containing at least 35% by weight of total surfactants, comprising:

(a) at least 35%, by weight of total surfactants, of a C₁₀-C₂₀ secondary (2,3) alkyl sulfate surfactant;

(b) at least 20%, by weight of total surfactants, of a solubilizing co-surfactant;

(c) the balance of the agglomerated particle comprising conventional, powdered detergent ingredients and fillers.

8. An agglomerated particle according to Claim 7 which comprises at least 40% by weight of a C₁₄-C₁₈ secondary (2,3) alkyl sulfate surfactant

9. An agglomerated particle according to either of Claims 7 or 8 wherein the co-surfactant is a member selected from the group consisting of ethoxylated alcohols, ethoxylated alkyl phenols, polyhydroxy fatty acid amides, alkyl polyglycosides, fatty ethanol amides and mixtures thereof.

10. An agglomerated particle according to either of Claims 7 or 8 wherein the co-surfactant is a member selected from the group consisting of primary alkyl sulfates, alkyl ethoxy sulfates, and mixtures thereof.

11. An agglomerate according to any of Claims 7-10 wherein the powdered ingredient (c) is selected from zeolite builders, layered silicate builders and mixtures thereof.