WO1998055586A1

WO1998055586A1 - Laundry bar compositions containing solid amine oxide surfactant composition

Info

Publication number: WO1998055586A1
Application number: PCT/US1997/009517
Authority: WO
Inventors: Isauro Manuel E. Misajon; Pamela Carlos Angeles; Robert Henry Callicott
Original assignee: The Procter & Gamble Company
Priority date: 1997-06-03
Filing date: 1997-06-03
Publication date: 1998-12-10
Also published as: AU3226997A

Abstract

The present invention is directed to a laundry bar composition comprising: a) from about 1 % to about 80 % anionic surfactant; b) from about 0.10 % to about 10 % solid amine oxide surfactant composition, wherein the solid amine oxide surfactant comprises 1) an amine oxide; and 2) a complexing acid selected from the group consisting of saturated carboxylic acid with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof; and c) optionally a detergent builder. Such a laundry bar composition satisfies the need for a laundry bar composition with acceptable physical properties, such as improved processing, good bar in-use properties, and good storage physical properties, while maintaining high sudsing.

Description

LAUNDRY BAR COMPOSITIONS CONTAINING SOLID AMINE OXIDE SURFACTANT COMPOSITION

FIELD

The present invention relates to laundry bar compositions containing solid amine oxide surfactant compositions.

BACKGROUND In societies where mechanical washing machines are not common, laundry detergent bars comprising synthetic organic surfactants and detergency builders are used in the laundering of clothes. Synthetic laundry bars typically comprise a synthetic anionic surfactant such as the alkali metal salt of an alkyl benzene sulfonic acid or alkali metal salt of an alkyl sulfate and one or more alkaline builders such as alkali metal polyphosphates, carbonates or silicates.

Technical developments in the field of laundry detergent bars have concerned formulating bars which are effective in cleaning clothes; which have acceptable sudsing characteristics in warm and cool water and in hard and soft water; which have acceptable in-use wear rates, hardness, durability, and feel; which have low smear; and which have a pleasing odor and appearance. Methods for making laundry detergent bars are also well known in the art. Prior art disclosing laundry bars and methods for making laundry bars include: U.S. Pat. 3,178,370, Okenfuss, issued April 13, 1965; and Philippine Pat. 13,778, Anderson, issued September 23, 1980. Laundry bar compositions may comprise amine oxide surfactants. For use in solid detergent compositions such as bars, solid amine oxide surfactant formulations are desirable rather than typical amine oxide surfactant formulations that are commercially available, such as in liquid, gel, or paste form. One reason is that for processing considerations, bar ingredients should preferably be in solid physical forms. There have been many attempts at preparing amine oxide surfactants in solid or granular formulations. U.S. 5,399,296, granted on March 21 , 1995 to Wierenga et al. and U.S. 5,389,306 granted on February 14, 1995 to Wierenga et al. disclose solid amine oxide compositions containing amine oxide- maleic acid salts and the process for making such compositions. It has now been found that laundry bar compositions comprising solid amine oxide surfactant compositions provide bars with good physical properties, including good product delivery. For example, consumers desire good product delivery onto the wash surface, meaning the detergent spreads more easily on the fabric while covering a larger surface area. Not only does the detergent spread more easily, but the detergent spreads evenly along the surface of the bar, so that the bar retains close to its original shape even after use in several washes.

In addition, bars generate suds quickly after use, which also signals to the consumer that the bar has good product delivery. Generating a large amount of suds is also desired by consumers because it signals to consumers that cleaning is taking place and that enough detergent has been applied in the wash. Furthermore, bars containing solid amine oxide surfactant compositions retain a hard bar surface as opposed to a soft, mushy surface, even after the bars become wet while the consumer is washing with the bar. Such bars also dry faster after being used.

The foregoing considerations involving laundry detergent bar compositions containing solid amine oxide surfactant formulations indicate that there is a continuing need to provide such bar compositions. None of the existing art provides all of the advantages and benefits of the present invention.

SUMMARY The present invention is directed to a laundry bar composition comprising:

A. from about 1 % to about 80% anionic surfactant;

B. from about 0.10% to about 10% solid amine oxide surfactant composition, wherein the solid amine oxide surfactant comprises

1. an amine oxide; and

2. a complexing acid selected from the group consisting of saturated carboxylic acid with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof; and C. optionally a detergent builder.

Such a laundry bar composition satisfies the need for a laundry bar composition with acceptable physical properties, such as improved processing, good bar in-use properties, and good storage physical properties, while maintaining high sudsing.

These and other features, aspects, and advantages of the present invention will become evident to those skilled in the art from a reading of the present disclosure.

DETAILED DESCRIPTION

While this specification concludes with claims distinctly pointing out and particularly claiming that which is regarded as the invention, it is believed that the invention can be better understood through a careful reading of the following detailed description of the invention. All percentages, ratios, and proportions are by weight, all temperatures are expressed in degrees Celsius, molecular weights are in weight average, and the decimal is represented by the point (.), unless otherwise indicated. All ratios are weight ratios unless specifically stated otherwise. As used herein, "comprising" means that other steps and other ingredients which do not affect the end result can be added. This term encompasses the terms "consisting of and "consisting essentially of.

As used herein, the term "solid compositions" mean particulate (e.g. powders, granules, agglomerates) and non-particulate solids.

As used herein, all pKa and pH values are measured in water at 25°C. All cited references are incorporated herein by reference in their entireties.

Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention.

As used herein, the term "alkyl" means a hydrocarbyl moiety which is straight or branched, saturated or unsaturated. Unless otherwise specified, alkyl are preferably saturated or unsaturated with double bonds, preferably with one or two double bonds.

The term "tallow" is used herein in connection with materials with fatty acid mixtures which typically are linear and have an approximate carbon chain length distribution of 2% C14. 29% C^«|6- 23% C^<|8- 2% palmitoleic, 41% oleic, and 3% linoleic (the first three fatty acids listed are saturated). Other mixtures with similar distribution, such as those from palm oil and those derived from various animal tallow and lard, are also included within the term tallow. The tallow can also be hardened (i.e, hydrogenated) to convert part or all of the unsaturated fatty acid moieties to saturated fatty acid moieties. The term "coconut oil" is used herein in connection with materials with fatty acid mixtures which typically are linear and have an approximate carbon chain length distribution of about 8% Cβ, 7% C^n, 48% C_π2, 17% C14, 9% C<\Q, 2% Ci8_> ⁷% o'eic, and 2% linoleic (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distribution in their fatty acids, such as palm kernel oil and babassu oil, are included within the term coconut oil. Anionic surfactant

Anionic surfactants which are suitable for use herein include soap. As used herein, "soap" means salts of fatty acids. The fatty acids are linear or branched containing from about 8 to about 24 carbon atoms, preferably from about 10 to about 20 carbon atoms. The average carbon chain length for the fatty acid soaps is from about 12 to about 18 carbon atoms, preferably from about 14 to about 16 carbon atoms. Preferred salts of the fatty acids are alkali metal salts, such as sodium and potassium, especially sodium. Also preferred salts are ammonium and alkylolammonium salts. The fatty acids of soaps useful in the subject invention bars are preferably obtained from natural sources such as plant or animal esters; examples include coconut oil, palm oil, palm kernel oil, olive oil, peanut oil, corn oil, sesame oil, rice bran oil, cottonseed oil, babassu oil, soybean oil, castor oil, tallow, whale oil, fish oil, grease, lard, and mixtures thereof. Preferred fatty acids are obtained from coconut oil, tallow, palm oil (palm stearin oil), palm kernel oil, and mixtures thereof. Fatty acids can be synthetically prepared, for example, by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process.

Alkali metal soaps can be made by direct saponification of the fats and oils or by the neutralization of the free fatty acids which are prepared in a separate manufacturing process. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium and potassium tallow and coconut soaps.

Preferred soap raw materials for the subject invention bars are soaps made from mixtures of fatty acids from tallow and coconut oil. Typical mixtures have tallow: coconut fatty acid ratios of 85:15, 80:20, 75:25, 70:30, and 50:50; preferred ratios are about 80:20 to 65:35.

Preferred soap raw materials for the subject invention are neat soaps made by kettle (batch) or continuous saponification. Neat soaps typically comprise from about 65% to about 75%, preferably from about 67% to about 72%, alkali metal soap; from about 24% to about 34%, preferably from about 27% to about 32%, water; and minor amounts, preferably less than about 1% total, of residual materials and impurities, such as alkali metal chlorides, alkali metal hydroxides, alkali metal carbonates, glycerin, and free fatty acids. Another preferred soap raw material is soap noodles or flakes, which are typically neat soap which has been dried to a water content of from about 10% to about 20%. The other components above are proportionally concentrated.

Other anionic surfactants which are suitable for use herein include the water-soluble salts, preferably the alkali metal, ammonium and alkylolammonium salts of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 10 to about 20 carbon atoms and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl groups.) Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (Cβ-is carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkyl benzene sulfonates in which the alkyl group contains from about 9 to about 15 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U.S. Patents 2,220,099 and 2,477,383. Especially valuable are linear straight chain alkyl benzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 11 to 13, abbreviated as C1 -J.13 LAS. The alkali metal salts, particularly the sodium salts of these surfactants are preferred. Alkyl benzene sulfonates and processes for making them are disclosed in U.S. Patent Nos. 2,220,099 and 2,477,383. Other anionic surfactants suitable for use herein are the sodium alkyl glyceryl ether sulfonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates. Preparation of alkyl glyceryl ether sulfonates are described in detail in U.S. Pat. 3,024,273, Whyte et al., issued March 6, 1962. Another suitable anionic surfactant for use herein are sodium or potassium salts of alkyl ethoxy ether sulfates (AES) having the following formula:

RO(C2H4θ)χSθ3M In the above structure R is alkyl of from about 10 to about 20 carbon atoms. On average, R is from about 13 to about 16. R is preferably saturated and linear.

In the above structure, x is an integer from 0.5 to about 20 and M is a water-soluble cation, for example, an alkali metal cation (e.g., sodium, potassium, lithium), preferably sodium or potassium, especially sodium. The preferred AES surfactant has a saturated linear alkyl with an average of 14 to 15 carbon atoms, a range of from about 14 to about 15 carbon atoms, an average of about one ethoxy unit per molecule, and is a sodium salt (C-|4- 15AEιSθ3Na).

In addition, suitable anionic surfactants include the water-soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1-sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; water-soluble salts of olefin and paraffin sulfonates containing from about 12 to 20 carbon atoms; and beta-alkyloxy alkane sulfonates containing from about 1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms in the alkane moiety.

The amount of anionic surfactant in the composition herein is from about 1% to about 80%, preferably from about 20% to about 50%, by weight of the composition.

One preferred type of laundry bar composition comprises a combination of soap and synthetic anionic surfactant in addition to containing solid amine oxide surfactant compositions. Preferred anionic surfactants are C-jrj-18 linear alkyl benzene sulfonates, Ci0-14 alkyl glyceryl ether sulfonates, C-J O-18 ^alkY' sulfates, and mixtures thereof. In these compositions, the amount of synthetic anionic surfactant to soap is in a ratio of from about 1 :1 to about 1:60. Another preferred type of laundry bar composition comprises synthetic anionic surfactants and solid amine oxide surfactant compositions, but no soap. In these compositions, the amount of synthetic anionic surfactant in the final bar composition is from about 5% to about 60%.

Solid Amine Oxide Surfactant

Solid amine oxide surfactant compositions suitable for use herein comprise: a. an amine oxide; and b. a complexing acid selected from the group consisting of saturated carboxylic acid with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof.

The solid amine oxide surfactant compositions are prepared by a process comprising admixing the complexing acid with an amine oxide surfactant formulation by admixing 1 mole of complexing acid with X mole(s) of amine oxide, where X is from about 1 to about equal to the number of acid groups of the complexing acid. The pH of the admixture is from about 1 to about 3, whereby a visible precipitate in the admixture is formed. The formed precipitate is separated from the admixture, preferably by mechanical means, and allowed to dry. The separated precipitate forms the solid compositions of the present invention, which solid compositions consist of the amine oxide and complexing acid described above.

Amine oxide formulations for use in the solid amine oxide surfactant comprise varying amounts of amine oxide surfactant therein. Such amine oxide formulations, and the processes for preparing them, are well known in the surfactant art. The amine oxide formulations for use in the instant process comprise varying percentages of amine oxide surfactant. Amine oxide surfactants are commercially available in many physical forms, including liquid, paste, gel and solid. The percentage of amine oxide surfactant in the formulation, as well as the type of such amine oxide surfactant, are not critical to the successful operation of the instant process. Accordingly, any known or conventional amine oxide formulation can be used. Such known or conventional formulations typically contain from about 3% to about 80%, more typically from about 5% to about 20%, most preferably from about 5% to about 10% by weight of amine oxide surfactant in a dilute water solution. It is understood, however, that formulations containing higher and lower concentrations of amine oxide surfactant can also be used in the instant process.

Amine oxide surfactants for use in the instant process preferably have the formula RR'R"NO, where R is a substituted or unsubstituted alkyl or alkenyl group containing from about 6 to about 30, preferably about 8 to 18 carbon atoms. Groups R' and R" are each substituted or unsubstituted alkyl or alkenyl groups containing from about 1 to about 18, preferably from about 1 to about 4, carbon atoms. More preferably, R' and R" are each methyl groups, examples of which include dodecyldimethyl amine oxide, tetradecyldimethyl amine oxide, hexadecyldimethyl amine oxide, octadecyldimethyl amine oxide, and coconutalkyldimethylamine oxides.

Examples of suitable amine oxide surfactants for use in the instant process include, but are not limited to, dodecyldimethyl amine oxide, tridecyldimethyl amine oxide, tetradecyldi-methyl amine oxide, pentadecyldimethyl amine oxide, hexadecyldimethyl amine oxide, heptadecyldimethyl amine oxide, octadecyldimethyl amine oxide, dodecyldiethyl amine oxide, tetradecyldimethyl amine oxide, hexadecyldiethyl amine oxide, octadecyldiethyl amine oxide, dodecyldipropyl amine oxide, tetradecyldipropyl amine oxide, hexadecyldipropyl amine oxide, octadecyldipropyl amine oxide, dodecyldibutyl amine oxide, tetradecyldibutyl amine oxide, hexadecyldibutyl amine oxide, octadecyldibutyl amine oxide, dodecylmethylethyl amine oxide, tetradecylethylpropyl amine oxide, hexadecylpro-pylbutyl amine oxide, and octadecylmethylbutyl amine oxide.

Another preferred amine oxide is ADMOX™, which is a C-J4 amine oxide dihydrate. ADMOX™ and other amine oxides useful in the present process are set forth in U.S. Patent No. 5,292,955 (Smith and Sauer, issued March 8, 1994).

Also useful are amine oxide surfactants made by the oxidation of tertiary amines prepared from mixed alcohols obtainable from coconut oil. Such coconutalkyl amine oxides are preferred from an economic standpoint inasmuch as it is not necessary for the present purposes, to separate the mixed alcohol fractions into their pure components to secure the pure chain length fractions of the amine oxides.

Amine oxide formulations for use in the present process can be prepared by known and conventional methods. Such methods normally involve the controlled oxidation of tertiary amines to the corresponding amine oxide using a strong oxidizing agent. A preferred oxidizing agent is hydrogen peroxide. A dilute, or preferably concentrated (30% by weight of more), hydrogen peroxide solution is added in a stoichiometric or greater amount to a liquid solution containing the tertiary amine for conversion thereof to the amine oxide. Reaction rates and amine oxide yields can be improved by incorporation of catalysts and or chelating agents well known in the surfactant art for this particular application. Methods for making amine oxide surfactants are described, for example, in U.S. Patent 3,215,741 (Chadwick, issued November 2, 1965), U.S. Patent 3,223,647 (Drew and Voss, issued December 14, 1965), British Patent 437,566 (issued October 31 , 1935), and U.S. Patent 4,565,891 (Correa and Riley, issued July 19, 1984).

Complexing acid is defined as a saturated carboxylic acid with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof. Such complexing acids will effectively precipitate amine oxide surfactants from the amine oxide formulations. As used herein, the term "carboxylates" means carboxyl-containing compounds generally.

The complexing acids of the present invention can be in a powdery form, or in an aqueous solution, although the physical form of the complexing acid is not critical to the invention. The complexing acid is soluble in water at less than about 35°C.

Examples of saturated and unsaturated carboxylic acids with at least 5 carbon atoms includes citric acid, polyacrγlic acid, malonic acid, adipic acid, oxalic acid, glutaric acid, pthalic acid, iauric acid, oleic acid, benzoic acid, and butyric acid. Examples of phosphonic acids include tetra sodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), diethylene triamine penta methyl phosphonic acid, hydroxyethane diphosphonic acid, and ethylenediamine tetra methylene phosphonic acid.

Preferred polyacrylic acids have a molecular weight range of from about 2,500 to 70,000, preferably a molecular weight range of from about 10,000 to about 50,000.

Water soluble salts of the complexing acid can also be used in the instant process. Such salts can comprise alkali metals (e.g., sodium, potassium), alkali earth metals, ammonium, substituted ammonium, and so forth. Preferred among such salts are sodium citrate, diammonium citrate, sodium tripolyphosphate and sodium pyrophosphate. Other water soluble salts can be used in the instant process provided that such salts are compatible with the amine oxide surfactant selected for use herein.

An essential step in the instant process is adding the complexing acid in the requisite amounts to the amine oxide formulation to form a solid amine oxide surfactant composition. It is preferred that the amine oxide be diluted in a water solution, having an active level of from about 3% to about 80%, preferably from about 5% to about 20%, most preferably from about 5% to about 10%. pH adjustment of the amine oxide formulation to the requisite level to about 1 to about 3 is normally needed when the complexing acid is used in the instant process. Precipitation of the desired amine oxide salt will not occur to any large extent until such admixture pH values are realized.

The process of making the solid amine oxide surfactant composition is described herein in terms of the addition of the complexing acid to an amine oxide formulation. It is understood, however, that any reference herein to complexing acid implicitly includes salts of complexing acids (described herein before), complexing acids which are acids, and mixtures thereof.

The process of making the solid amine oxide surfactant composition comprises admixing the complexing acid and an amine oxide formulation to form a visible precipitate therein, and then separating the formed precipitate from the admixture. The process is described in detail as follows.

In a first step of the process, one mole of a complexing acid and X moles of an amine oxide formulation described herein (10% active in a dilute solution of water) are admixed, wherein X is from about 1 to about equal to the number of acid groups of the complexing acid. The pH of the admixture is from about 1 to about 3, whereby a visible precipitate in the admixture is formed.

The formed precipitate made in accordance with the instant process is a salt of the amine oxide surfactant and complexing acid.

In one preferred method, an excess of complexing acid is used to accelerate the formation of the precipitate. An excess of about 30% complexing acid above the molar amount described above is preferred.

In a second step of the process herein, the formed precipitate is separated from the admixture. Preferably, such separation is accomplished by mechanical means such as screening, filtering, centrifuging and the like. The separated precipitate can then be washed with cold water (pH adjusted to about the pKa of the amine oxide) to remove unprecipitated reactants, and then dried to form a solid formulation. Preferably, significantly all of the impurities have been removed from the water before washing. The solid formulation can be reduced to fine particles, agglomerated, and so forth. Since the precipitate can be separated by mechanical means, there is no need to use organic extraction solvents to perform such separations. It is understood, however, that the use of organic extraction solvents can be used in the instant process, but that their use is neither preferred or necessary. Water of hydration of the formed complex will vary depending on the drying operation utilized, e.g., air drying, forced air drying, convection hot air drying, organic solvent drying/washing, and so forth.

The following examples illustrate the process of making the solid amine oxide surfactant compositions to be contained in the laundry bar compositions of the present invention. Examples of the invention are set forth hereinafter by way of illustration and are not intended to be in any way limiting of the invention.

Example 1 About 0.92 grams of citric acid complexing acid is admixed with about 30 grams of amine oxide solution (C14 alkyldimethyl amine oxide, 10% active in a solution of water). The molar ratio of complexing acid to active amine oxide is about 1:2. The pH of the admixture of amine oxide solution and citric acid is from about 1 to about 3. pH is adjusted with the addition of excess citric acid. A visible precipitate forms almost immediately. The admixture is allowed to set for about 5 minutes. The precipitate is then filtered from the admixture, washed with water (pH of 7), in which the water has substantially all the impurities removed, and air dried before it is reduced to a fine powder. The citric acid is preferably in a powder form.

Example 2 The process described in Example 1 is repeated, except that 30 grams of C16 alkyldimethyl amine oxide (7.85% solution) is admixed with a solution of 0.76 grams of citric acid, thereby forming a precipitate. After adding the initial citric acid and after the precipitate is formed, an additional 0.40 grams of citric acid is added to adjust the viscosity. The molar ratio of complexing acid to active amine oxide is 1:1.5.

Example 3 The process described in Example 1 is repeated, except that 5.27 grams of C16 alkyldimethyl amine oxide (6.4% solution) is admixed with a solution of

0.09 grams of citric acid. The molar ratio of complexing acid to active amine oxide is 1 :3, and the pH of C16 alkyldimethyl amine oxide solution is adjusted using 1 N HCI to a pH of 0.97, before the addition of the citric acid.

Example 4

The process described in Example 1 is repeated except that 365 grams of

C14 alkyldimethyl amine oxide (10% solution) is admixed with 0.34 grams of

STPP complexing acid (98% active). The molar ratio of complexing acid to active amine oxide is 1 :5, and the pH is adjusted using 1 N HCI to a pH of 1.26 before the addition of STPP.

Example 5

The process described in Example 1 is repeated except that 20 grams of

C14 alkyldimethyl amine oxide (10% solution) is admixed with 4.31 grams of diethylene triamine penta methyl phosphonic acid (25% active). The molar ratio of complexing acid to active amine oxide is 1 :5, and the pH is adjusted using 1N

HCI to a pH of 1.0 before the addition of the complexing acid.

Example 6 The process described in Example 1 is repeated except that 47 grams of C14 alkyldimethyl amine oxide (9.8% solution) is admixed with 9.35 grams of polyacrylic acid (molecular weight 4,500) complexing acid (48% active). The molar ratio of complexing acid to active amine oxide is 1 :24. No pH adjustment is necessary before the addition of the polyacrylic acid.

The laundry bar compositions of the present invention comprises from about 0.10% to about 10%, preferably from about 1 % to about 5% solid amine oxide surfactant composition. Adjunct Ingredients Builder

The laundry bars of the invention can contain as an optional ingredient from about 1% to about 50%, preferably from about 5% to about 30% detergent builder. These detergent builders can be, for example, water-soluble alkali-metal salts of phosphate, pyrophosphates, orthophosphates, tripolyphosphates, higher polyphosphates, and mixtures thereof. Preferred builders are a water-soluble alkali-metal salt of tripolyphosphate, and a mixture of tripolyphosphate and pyrophosphate. The builder can also be a non-phosphate detergent builder. Specific examples of non-phosphate, inorganic detergency builders include water-soluble inorganic carbonate and bicarbonate salts. The alkali metal (e.g., sodium and potassium) carbonates, bicarbonates, and silicates are particularly useful herein. Specific preferred examples of builders include sodium tripolyphosphates (STPP) and tetra sodium pyrophosphates (TSPP), and mixtures thereof. Other specifically preferred examples of builders include zeolites and polycarboxylates.

Sodium carbonate is a particularly preferred ingredient in the subject invention compositions, since in addition to its use as a builder, it can also provide alkalinity to the composition for improved detergency, and also can serve as a neutralizing agent for acidic components added in the composition processing. Sodium carbonate is particularly preferred as a neutralizing inorganic salt for an acid precursor of an anionic surfactant used in such compositions, such as the alkyl ether sulfuric acid and alkyl benzene sulfonic acid.

Co-polymers of acrylic acid and maleic acid are preferred in the subject compositions as auxiliary builders, since it has been observed that their use in combination with fabric softening clay and clay flocculating agents further stabilizes and improves the clay deposition and fabric softening performance. Bleach

A preferred optional component in the laundry bar is an oxygen bleach component. The oxygen bleaching component can be a source of ^_OOH group, such as sodium perborate monohydrate, sodium perborate tetrahydrate and sodium percarbonate. Sodium percarbonate (2Na2Cθ3-3H2θ2) is preferred since it has a dual function of both a source of HOOH and a source of sodium carbonate. Another optional bleaching component is a peracid per se, such as a formula:

CH3(CH2)w-NH-C(0)-(CH2)zC03H wherein z is from 2 to 4 and w is from 4 to 10. The bleaching component can contain, as a bleaching component stabilizer, a chelating agent of polyaminocarboxylic acids, polyaminocarboxylates such as ethylenediaminotetraacetic acid, diethylenetriaminopentaacetic acid, and ethylenediaminodisuccinic acid, and their salts with water-soluble alkali metals. The bleach components, if any, can be added to the bar, if any, at a level up to 20%, preferably from about 1% to about 10%, more preferably from about 2% to about 6%.

When oxygen bleach is used, it is preferred that the dihydric alcohol be one wherein the two hydroxyl groups are separated by at least one carbon atom. Soil Suspending Agents

Soil suspending agents can be optionally used. In the present invention, their use is balanced with the fabric softening clay/clay flocculating agent combination to provide optimum cleaning and fabric softening performance. One such soil suspending agent is an acrylic/maleic copolymer, commercially available as Sokoian®, from BASF Corp. Other soil suspending agents include polyethylene glycols having a molecular weight of about 400 to 10,000, and ethoxylated mono- and polyamines, and quaternary salts thereof. A highly preferred soil suspending agent is a water-soluble salt of carboxymethylcellulose and carboxyhydroxymethylcellulose. Soil suspending agents should be used at levels up to about 5%, preferably about 0.1-1 %. Other Optional Surfactants

The detergent bars of the present invention can contain other optional ingredients commonly used in detergent products. A typical listing of the classes and species of optional surfactants, (e.g. nonionic, zwitterionic and amphoteric surfactants) optional alkaline builders such as sodium carbonate trisodium phosphate sodium silicate, etc. and other ingredients useful herein appears in U.S. Pat. No. 3,664,961 , issued to Norris on May 23, 1972, and EP 550,652, published on April 16, 1992. Such optional surfactants, if present, can be included at levels up to a total of about 10%, preferably about 0.5-3%. In addition, a hydrotrope, or mixture of hydrotropes, can be present in the laundry detergent bar. Preferred hydrotropes include the alkali metal, preferably sodium, salts of toluene sulfonate, xylene sulfonate, cumene sulfonate, sulfosuccinate, and mixtures thereof. Preferably, the hydrotrope is added to the linear alkyl benzene sulfonic acid prior to its neutralization. The hydrotrope, if present, will preferably be present at from about 0.5% to about 5% of the laundry detergent bar. Fabric Softening Clav

The fabric softening clay is preferably a smectite-type clay. The smectite- type clays can be described as expandable, three-layer clays; i.e., alumino- silicates and magnesium silicates, having an ion exchange capacity of at least about 50 meq/100 g. of clay. Preferably the clay particles are of a size that they can not be perceived tactilely, so as not to have a gritty feel on the treated fabric of the clothes. The fabric softening clay can be added to the bar to provide about 1% to about 50% by weight of the bar, more preferably from about 2% to about 20%, and most preferably about 3% to 14%.

While any of the smectite-type clays described herein are useful in the present invention, certain clays are preferred. For example, Gelwhite GP is an extremely white form of smectite-type clay and is therefore preferred when formulating white granular detergent compositions. Volclay BC, which is a smectite-type clay mineral containing at least 3% iron (expressed as Fe2θ3) in the crystal lattice, and which has a very high ion exchange capacity, is one of the most efficient and effective clays for use in the instant compositions from the standpoint of product performance. On the other hand, certain smectite-type clays are sufficiently contaminated by other silicate minerals that their ion exchange capacities fall below the requisite range; such clays are of no use in the instant compositions. Clay Flocculating Agent

It has been found that the use of a clay flocculating agent in a laundry bar containing softening clay provides surprisingly improved softening clay deposition onto the clothes and clothes softening performance, compared to that of laundry bars comprising softening clay alone. The polymeric clay flocculating agent is selected to provide improved deposition of the fabric softening clay. Typically such materials have a high molecular weight, greater than about 100,000. Examples of such materials can include long chain polymers and copolymers derived from monomers such as ethylene oxide, acrylamide, acrylic acid, dimethylamino ethyl methacrylate, vinyl alcohol, vinyl pyrrolidone, and ethylene imine. Gums, like guar gums, are suitable as well. The preferred clay flocculating agent is a poly(ethylene oxide) polymer. The amount of clay flocculating agent, if any, is about 0.2-2%, preferably about 0.5-1%. Other Optional Adjunct Ingredients

A particularly preferred optional component of the present invention is a detergent chelant. Such chelants are able to sequester and chelate alkali cations (such as sodium, lithium and potassium), alkali metal earth cations (such as magnesium and calcium), and most importantly, heavy metal cations such as iron, manganese, zinc and aluminum. Preferred cations include sodium, magnesium, zinc, and mixtures thereof. The detergent chelant is particularly beneficial for maintaining good cleaning performance and improved surfactant mileage, despite the presence of the softening clay and the clay flocculating agent. The detergent chelant is preferably a phosphonate chelant, particularly one selected from the group consisting of diethylenetriamine penta(methylene phosphonic acid), ethylene diamine tetra(methylene phosphonic acid), and mixtures and salts and complexes thereof, and an acetate chelant, particularly one selected from the group consisting of diethylenetriamine penta(acetic acid), ethylene diamine tetra(acetic acid), and mixtures and salts and complexes thereof. Particularly preferred are sodium, zinc, magnesium, and aluminum salts and complexes of diethylenetriamine penta(methylene phosphonate) diethylenetriamine penta (acetate), and mixtures thereof.

Preferably such salts or complexes have a molar ratio of metal ion to chelant molecule of at least 1 :1 , preferably at least 2:1.

The detergent chelant can be included in the laundry bar at a level up to about 5%, preferably from about 0.1% to about 3%, more preferably from about 0.2% to about 2%, most preferably from about 0.5% to about 1.0%.

Another preferred additional component of the laundry bar is fatty alcohol having an alkyl chain of 8 to 22 carbon atoms, more preferably from 12 to 18 carbon atoms. A preferred fatty alcohol has an alkyl chain predominantly containing from 16 to 18 carbon atoms, so-called "high-cut fatty alcohol," which can exhibit less base odor of fatty alcohol relative to broad cut fatty alcohols. Typically fatty alcohol, if any, is present in the laundry bar at up to a level of 10%, more preferably from about 0.75% to about 6%, most preferably from about 2% to about 5%. The fatty alcohol is generally added to a laundry bar as free fatty alcohol. However, low levels of fatty alcohol can be introduced into the bars as impurities or as unreacted starting material. For example, laundry bars based on coconut fatty alkyl sulfate can contain, as unreacted starting material, from 0.1 % to 3.5%, more typically from 2% to 3%, by weight of free coconut fatty alcohol on a coconut fatty alkyl sulfate basis.

Another preferred optional component in the laundry bar is a dye transfer inhibiting (DTI) ingredient to prevent diminishing of color fidelity and intensity in fabrics. A preferred DTI ingredient can include polymeric DTI materials capable of binding fugitive dyes to prevent them from depositing on the fabrics, and decolorization DTI materials capable of decolorizing the fugitives dye by oxidation. An example of a decolorization DTI is hydrogen peroxide or a source of hydrogen peroxide, such as percarbonate or perborate. Non-limiting examples of polymeric DTI materials include polyvinylpyrridine N-oxide, polyvinylpyrrolidone (PVP), PVP-polyvinylimidazole copolymer, and mixtures thereof. Copolymers of N-vinylpyrrolidone and N-vinylimidazole polymers (referred to as "PVPI") are also preferred for use herein. The amount of DTI included in the subject compositions, if any, is about 0.05-5%, preferably about 0.2-2%. Another preferred optional component in the laundry bar is a secondary fabric softener component in addition to the softening clay. Such materials can be used, if any, at levels of about 0.1% to 5%, more preferably from 0.3% to 3%, and can include: amines of the formula R4R5R6N, wherein R4 is C5 to C22 hydrocarbyl, R5 and R6 are independently C1 to C10 hydrocarbyl. One preferred amine is ditallowmethyl amine; complexes of such amines with fatty acid of the formula R7COOH, wherein R7 is Cg to C22 hydrocarbyl, as disclosed in EP No. 0,133,804; complexes of such amines with phosphate esters of the formula R8θ-P(0)(OH)-ORg and HO-P(0)(OH)-ORg, wherein Re and Rg are independently C1 to C20 alkyl of alkyl ethoxylate of the formula -alkyl- (OCH2CH2); cyclic amines such as imidazoiines of the general formula 1 -(higher alkyl) amido (lower alkyl)-2-(higher alkyl)imidazoline, where higher alkyl is from 12 to 22 carbons and lower alkyl is from 1 to 4 carbons, such as described in UK Patent Application GB 2,173,827; and quaternary ammonium compounds of the formula R10R11R12R13 ⁺X^", wherein R10 is alkyl having 8 to 20 carbons, R11 is alkyl having 1 to 10 carbons, R12 and R13 are alkyl having 1 to 4 carbons, preferably methyl, and X is an anion, preferably Cl" or Br, such as C12-I3 alkyl trimethyl ammonium chloride. Fillers

Fillers may be optionally added to the bar composition. Starch can also be used as a filler which is added before the milling stage in the manufacture of the bar composition.

Sodium sulfate is a well-known filler that is compatible with the compositions of this invention. It can be a by-product of the surfactant sulfation and sulfonation processes, or it can be added separately. Other filler materials include bentonite and talc. Calcium carbonate (also known as Calcarb) is also a well known and often used filler component of laundry bars. Fillers include minerals, such as talc and hydrated magnesium silicate-containing minerals, where the silicate is mixed with other minerals, e.g., old mother rocks such as dolomite. Filler materials are typically used, if included, at levels up to 40%, preferably from about 5% to about 25%.

Binding agents for holding the bar together in a cohesive, soluble form can also be used, and include natural and synthetic starches, gums, thickeners, and mixtures thereof. Such materials, if included, are typically at levels up to about 3%, preferably about 0.5-2% Other adjunct materials

Glycerine is commonly incorporated in laundry bar compositions. If included, it is typically at concentrations up to about 3%, preferably about 0.5- 1.5%. Optical brighteners are also preferred optional ingredients in laundry bars of the present invention. Preferred optical brighteners are diamino stilbene, distyrilbiphenyl-type optical brighteners. Preferred as examples of such brighteners are 4,4'-bis{[4-anilino-6-bis(2-hydroxyethyl) amino-1,3,5-trizin-2- yl]amino}stilbene-2,2'-disulfonic acid disodium salt, 4-4'-bis(2-sulfostyryl) biphenyl and 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl) aminojstilbene- 2,2'-disulfonic acid disodium salt. Such optical brighteners, or mixtures thereof, can be used at levels in the bar of from about 0.05% - 1.0%.

Dyes, pigments, germicides, and perfumes can also be added to the bar composition. If included, they are typically at levels up to about 0.5%.

Another optional component of the subject invention composition is a photobleach material, particularly phthalocyanine photobleaches which are described in U.S. Patent 4,033,718 issued July 5, 1977, incorporated herein by reference. Preferred photobleaches are metal phthalocyanine compounds, the metal preferably having a valance of +2 or +3; zinc and aluminum are preferred metals. Such photobleaches are available, for example, under the tradename TINOLUS or as zinc phthalocyanine sulfonate. The photobleach components, if included, are typically in the subject compositions at levels up to about 0.02%, preferably from about 0.001% to about 0.015%, more preferably from about 0.002% to about 0.01%.

Another useful optional component of the subject compositions are detergent enzymes. Particularly preferred are cellulase, lipase, protease, amylase, and mixtures thereof. Enzymes, if included, are typically at levels up to about 5%, preferably about 0.5-3%.

Processing

The laundry bars of the present invention can be processed in conventional soap or detergent bar making equipment with some or all of the following key equipment: blender/mixer, mill, refining plodder, two-stage vacuum plodder, logo printer/cutter, cooling tunnel and wrapper.

In a typical process the raw materials are mixed in the blender. The anionic surfactant and amine oxide surfactant composition are first premixed in the blender. The preferred mixer type to be used is a high shear mixer. Suitable equipment can include: Sigma (single arm or double arms) blender, manufactured by Mazzoni; Winkworth RT 25 series, manufactured by Winkworth

Machinery Ltd, Berkshire, UK; Eirich, series RV, manufactured by Gustau Eirich

Hardheim, Germany; Lodege, series FM for batch mixing; series Baud KM for continuous mixing, manufactured by Lodege Machinenbau GmbH. Other types of suitable mixers for this application are Twin Screw Extruders, supplied by APV

Bakes (CP series), Werner and Pfleiderer (continua series).

Optional other surfactants are added, followed by the builder and any additional optional components. If desired, polyphosphate can be used as an alkaline salt in the neutralization. The mixing can take from one minute to one hour, with the usual mixing time being from about ten to twenty minutes. The blender mix is then charged to a surge tank. The product is conveyed from the surge tank to the mill via a multi-screw conveyer.

After milling and optionally, preliminary plodding, the product is then conveyed to a double vacuum plodder, operating at high vacuum, e.g. 400 to

740 mm of mercury vacuum, so that entrapped air is removed. The product is extruded and cut to the desired bar length, and printed with the product brand name. The printed bar can be cooled, for example in a cooling tunnel, before it is wrapped, cased, and sent to storage. Examples of the invention are set forth hereinafter by way of illustration and are not intended to be in any way limiting of the invention. LAUNDRY BAR COMPOSITIONS

Laundry bars of the present invention, having the following compositions are prepared by the blending, milling and plodding procedures as described above.

Examples 6-8 showing compositions in % wei ht

** - additives such as Polymers, Brighteners, Perfume, etc. a - the solid amine oxide surfactant composition of Example 1 b - the solid amine oxide surfactant composition of Example 2 c - the solid amine oxide surfactant composition of Example 3

Claims

WHAT IS CLAIMED IS:

1. A laundry bar composition comprising:

A. from about 1 % to about 80% anionic surfactant;

B. from about 0.10% to about 10% solid amine oxide surfactant composition, wherein the solid amine oxide surfactant comprises 1. an amine oxide; and

2. A laundry bar composition as claimed in Claim 1 , wherein the complexing acid is selected from the group consisting of citric acid, polyacrylic acid, malonic acid, adipic acid, oxalic acid, glutaric acid, pthalic acid, iauric acid, oleic acid, benzoic acid, and butyric acid, tetra sodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), diethylene triamine penta methyl phosphonic acid, hydroxyethane diphosphonic acid, ethylenediamine tetra methylene phosphonic acid, and mixtures thereof.

3. A laundry bar composition as claimed in Claim 1 , wherein the amine oxide has the formula RR'R"NO, where R is a substituted or unsubstituted alkyl or alkenyl group containing from about 6 to about 30 carbon atoms and Groups R' and R" are each substituted or unsubstituted alkyl or alkenyl groups containing from about 1 to about 18 carbon atoms.

4. A laundry bar composition as claimed in Claim 1 , wherein the polyacrylic acid has a molecular weight of from about 2500 to about 70,000.

5. A laundry bar composition as claimed in Claim 1 , further comprising from about 1% to about 50% detergent builder.

6. A laundry bar composition as claimed in Claim 5, wherein the detergent builder is selected from the group consisting of water-soluble alkali-metal salts of phosphate, pyrophosphates, orthophosphates, tripolyphosphates, higher polyphosphates, and mixtures thereof.

7. A laundry bar composition as claimed in Claim 5, wherein the anionic surfactant is a synthetic anionic surfactant selected from the group consisting of C-| Q-18 linear alkyl benzene sulfonates, C-|0-14 alkyl glyceryl ether sulfonates, C-J O-18 alkyl sulfates, and mixtures thereof.

8. A laundry bar composition as claimed in Claim 5, wherein the anionic surfactant is comprised of synthetic anionic surfactant and soap at a ratio of anionic synthetic surfactant to soap from about 1:1 to about 1 :60.

9. A laundry bar composition as claimed in Claim 5, comprising from about 1% to about 5% solid amine oxide surfactant composition.