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 leasing odor and appearance.

Methods for making laundry detergent bars are also well known in the art.

Known laundry bars and methods for making laundry bars include those disclosed in: U. S. Patent 3,178,370 (Okenfuss, issued April 13,1965); and Philippine Patent 13,778 (Anderson, issued September 23,1980).

Amine oxide surfactants are commonly used in liquid cleaning compositions to boost and maintain suds formation, and/or improve cleaning, and/or improve mildness to skin. Such compositions include, for example, laundry and dishwashing detergent compositions. However, while a laundry cleaning product formula can be very effective in delivering desired attributes, it may not qualify as a usable product if it also has serious processability problems. For example, the addition of high active (solid or paste) or dilute (liquid) form amine oxides have proven difficult to properly incorporate into a solid detergent composition. Even if such amine oxides are successfully incorporated, the final product lacks acceptable physical properties.

Based on the foregoing, there is a need for a laundry detergent bar which comprises an amine oxide in combination with soap and linear alkyl benzene sulfonate, yet maintains acceptable physical properties.

SUMMARY The present invention is directed to a laundry detergent bar composition comprising a) from about 35% to about 50% soap; b) from about 5% to about 10% linear alkyl benzene sulfonate; c) from about 1% to about 4% amine oxide component; and from about 0.5% to about 30% moisture.

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 the specification concludes with claims which particularly point out and distinctly claim the invention, it is believed the present invention will be better understood from the following description.

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.

All percentages are by weight of total composition unless specifically stated otherwise.

All ratios are weight ratios unless specifically stated otherwise.

Herein,"alkenyl"means a carbon-containing chain, preferably from about C10 to about C20, more preferably from about C12 to about C1g, more preferably still from about C12 to about C16; which may be straight, branched or cyclic, preferably branched or straight, more preferably straight; substituted (mono-or poly-) or unsubstituted; and monounsaturated (i. e., one double or triple bond in the chain), or polyunsaturated (i. e., two or more double bonds in the chain, two or more triple bonds in the chain, or one or more double and one or more triple bonds in the chain), preferably monounsaturated Herein,"alkyl"means a carbon-containing chain, preferably from about C10 to about C20, more preferably from about C12 to about C1g, more preferably still from about C12 to about C16; which may be straight, branched or cyclic, preferably straight or branched, more preferably straight; substituted (mono-or poly-) or unsubstituted; and saturated.

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'.

Herein,"LAS"means linear alkyl benzene sulfonate.

Herein,"tallow"is used in connection with materials with fatty acid mixtures which typically are linear and have an approximate carbon chain

length distribution of 2% C14,29% C16,23% C1g, 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.

Herein,"coconut oil"is used in connection with materials with fatty acid mixtures which typically are linear and have an approximate carbon chain length distribution of about 8% Cg, 7% C10,48% Cri2,17% C14,9% C16,2% C1g, 7% oleic, 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.

In accordance with the present invention, it has been found that certain optimal levels of soap, LAS and amine oxide provide improved cleaning, whitening, oily/greasy soil removal, and/or calcium tolerance, versus other levels of the same components in a laundry detergent bar composition.

A. Soap 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 laundry bar composition 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 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 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.

Soaps are used in the present composition at levels of from about 35% to about 50%, by weight of the resulting laundry detergent bar composition; more preferably from about 35% to about 40%.

B. Linear Alkvl Benzene Sulfonate The laundry bar composition of the present invention preferably comprises from about 5% to about 10% LAS, more preferably from about 7% to about 10% LAS. Particularly preferred for optimum sudsing is a soap/LAS ratio of 9: 1.

C. Amine Oxide Component The amine oxide component may be either an amine oxide, a high active amine oxide complex, or mixtures thereof.

Amine oxide surfactants employed in the laundry detergent bar preferably have the formula R1 R2R3No, wherein R is a substituted or unsubstituted alkyl or alkenyl preferably containing from about 8 to about 30 carbon atoms; more preferably from about 8 to about 18.

R2 and R3 are independently substituted or unsubstituted alkyl or alkenyl groups preferably containing from about 1 to about 18 carbon atoms, more preferably from about 1 to about 4. More preferably, R2 and R3 are independently methyl groups; examples of such amine oxides include, dodecyidimethyl amine oxide, tetradecyldimethyl amine oxide,

hexadecyidimethyl amine oxide, octadecyldimethyl amine oxide, and coconutalkyldimethyl amine oxides.

Examples of suitable amine oxides include dodecyldimethyl amine oxide, tridecyidimethyl amine oxide, tetradecyldimethyl amine oxide, pentadecyidimethyl amine oxide, hexadecyidimethyl amine oxide, heptadecyidimethyl amine oxide, octadecyldimethyl amine oxide, dodecyldiethyl amine oxide, tetradecyldimethyl amine oxide, hexadecyidiethyl amine oxide, octadecyldiethyl amine oxide, dodecyldipropyl amine oxide, tetradecyidipropyl amine oxide, hexadecyidipropyl amine oxide, octadecyldipropyl amine oxide, dodecyldibutyl amine oxide, tetradecyldibutyl amine oxide, hexadecyidibutyl amine oxide, octadecyldibutyl amine oxide, dodecylmethylethyl amine oxide, tetradecylethylpropyl amine oxide, hexadecylpropylbutyl amine oxide, and octadecylmethylbutyl amine oxide.

Preferred amine oxides include, C12-C1g alkyl dimethyl amine oxides, more preferably C14-C16 Another preferred amine oxide is ADMOXTM, which is a C14 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 alcools 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.

In a preferred embodiment, the amine oxide is a liquid amine oxide formulation. The percentage of amine oxide in the liquid amine oxide formulation as well as the type of amine oxide are not critical to the successful operation of the instant process, or the resulting laundry bar. Accordingly, any known or conventional liquid amine oxide formulation can be used. Preferably, liquid amine oxide formulations useful in the present invention have up to 50% amine oxide, more preferably from about 1% to about 50%, more preferably still from about 20% to about 40%. It is understood, however, that formulations containing higher or lower concentrations of amine oxide can also be used in the present process. However, more concentrated formulations are preferred from a manufacturing cost standpoint. The remainder of the liquid amine oxide

formulation will typically, and preferably, be water. Less preferred liquid formulations are single phase mixtures of water and water-miscible solvents.

The liquid amine oxide formulations 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 stochiometric 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).

In an alternative embodiment, high active amine oxide complexes are used in the present process in combination with or in place of the above discussed amine oxides (i. e., non-complexed amine oxides). Generally speaking, such high active amine oxide complexes include solid amine oxide surfactant compositions comprising an amine oxide and 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. More specifically, the amine oxide of such a complex preferably has the formula R11R12R13No, where R is a substituted or unsubstituted alkyl or alkenyl group containing from about 6 to about 30 carbon atoms and Groups R12 and R13 are each substituted or unsubstituted alkyl or alkenyl groups containing from about 1 to about 18 carbon atoms. The complexing acid of such a complex preferably is selected from the group consisting of citric acid, polyacrylic acid, malonic acid, adipic acid, oxalic acid, glutaric acid, pthalic acid, lauric 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. Such complexes may be prepared by 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.

Other high active amine oxide complexes useful in the present invention include those disclosed in U. S. Patent 5,399,296 (Wierenga et a/., issued March 21,1995).

The amine oxide component is used in the present composition at levels of from about 1 % to about 4%, more preferably from about 1.5% to about 3%, more preferably still 2.5%. Particularly preferred for optimum sudsing is 2.4% amine oxide component. Particularly preferred for optimum cleaning and/or whitening performance, is a composition comprising 40% soap, 10% LAS, and 2.5% amine oxide component.

D. Moisture The laundry detergent bars preferably comprise from about 0.5% to about 30% of moisture, more preferably from about 15% to about 25%, more preferably still from about 1 % to about 5%. The moisture level can be determined by any methods known in the art, an example of which is the Carl Fischer Moisture Titration Method.

E. Synthetic Anionic Surfactants The laundry bar may further comprise one or more synthetic anionic surfactants. Synthetic 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 herein 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 alcools (Cg 18 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 valable 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 C11 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.

Preferred synthetic anionic surfactants are C10-18 linear alkyl benzene sulfonates, C10-14 alkyl glyceryl ether sulfonates, and C10-18 alkyl sulfates.

The amount of synthetic anionic surfactant is preferably from about 5% to about 60%, more preferably from about 15% to about 30%.

F. Acid Precursor of an Anionic Surfactant In a preferred process for making the laundry detergent bar, one or more acids are used to effect a neutralization reaction in the seat (the process is discussed in more detail, below). Such acids preferably include carboxylic acids, phosphoric acids, sulfuric acids, acid precursors of anionic surfactants, or mixtures thereof; more preferably citric acid, acetic acid, phosphoric acid, acid pyrophosphate, sulfuric acid, the acidic form of linear alkyl benzene sulfonate (HLAS), the acidic form of alkyl sulfate (HAS), or mixtures thereof; more preferably still, sulfuric acid and HLAS.

The amount of acid precursor of an anionic surfactant used in such a process (by weight of the resulting laundry detergent bar composition) is preferably from about 1% to about 10%, more preferably from about 2.5% to about 6%. However, if the acid is the acid precursor for LAS (i. e., HLAS), the preferred amounts correspond to those previously set forth for LAS.

G. Alkali Salts The laundry bar may further comprise an alkali salt. In addition to its possible use as a builder and providing alkalinity to the overall composition for improved detergency; the alkali salt serves as a neutralizing agent for the acid precursor of an anionic surfactant which is employed in a preferred process for making the laundry bar (discussed in more detail below).

Useful alkali salts include alkali metal carbonates, bicarbonates, and phosphates. Preferred alkali salts include sodium carbonate (soda ash), sodium bicarbonate; more preferably sodium carbonate.

The amount of alkali salt is preferably from about 2% to about 40%, more preferably from about 10% to about 20%.

H. Builders The laundry bars may further contain from about 0.5% to about 30%, more preferably from about 5% to about 15% 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, and co-polymers of acrylic acid and maleic acid.

I. Additional Inqredients The detergent bars may further include other ingredients commonly used in detergent products. A typical listing of the classes and species of additional surfactants, (e. g. nonionic, zwitterionic and amphoteric surfactants) additional 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 additional surfactants, if present, can be included at levels up to a total of about 10%, preferably about 0.5-3%.

A preferred additional component in the laundry bar is a bleach component. The bleaching component can be a source of-OOH group, such as sodium perborate monohydrate, sodium perborate tetrahydrate and sodium percarbonate. Sodium percarbonate (2Na2CO3-3H202) 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 (O)- (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%.

A preferred additional ingredient is a fabric softening clay, preferably a smectite-type clay and a clay flocculating agent, having a high molecular weight greater than about 100,000.

Soil suspending agents may be addition used. In the present invention, their use is balance 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, commercial available as SOKALAN@, 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 particularly preferred additional 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 may 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 alcools.

Typically fatty alcool, 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 alcool. 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 additional 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 additional 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 C9 to C22 hydrocarbyl, as disclosed in EP No. 0,133,804; complexes of such amines with phosphate esters of the formula R80-P (O) (OH)-ORg and HO-P (O) (OH)-ORg, wherein R8 and Rg are independently C1 to C20 alkyl of alkyl ethoxylate of the formula-alkyl- (OCH2CH2); cyclic amines such as imidazolines 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 R1OR11R12R13N+X-wherein R10 is alkyl having 8 to 20 carbons, Rn is alkyl having 1 to 10 carbons, Ri2 and Ri3 are alkyl having 1 to 4 carbons, preferably methyl, and X is an anion, preferably Cl-or Br, such as C12-13 alkyl trimethyl ammonium chloride.

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 Calcite) 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%.

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-hydoxyethyl) amino-1,3,5-trizin- 2-yl] amino} stilbene-2,2'-disulfonic acid disodium salt, 4-4'-bis (2-sulfostyryl) biphenyl and 5-triazin-2-yl) amino] stilbene- 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 may also be added to the bar composition. If included, they are typically at levels up to about 0.5%.

Another additional component useful in the present process is a photobleach material, particularly phthalocyanine photobleaches which are described in U. S. Patent 4,033,718 issued July 5,1977. 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%.

I. Processina While the laundry bar composition of the present invention may be made by any of the known laundry bar making processes, a preferred process comprises mixing the amine oxide component, an anionic surfactant (e. g., soap), an alkali salt, and subsequently adding an acid precursor of an anionic surfactant (e. g., HLAS).

Such a process can employ 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.

Typically in such a process, the raw materials (including the amine oxide component, anionic surfactant, and alkali salt) are mixed in the blender. This initial mixture is referred to as the seat. The acid (e. g., a precursor of an anionic surfactant) is subsequently added to the seat. The resulting partly neutralized mixture is mechanically worked to effect homogeneity and to complete the neutralization of the mixture. Once the neutralization reaction is completed, additional soap (preferably having a temperature preference of 70°C to about 85°C) and other optional surfactants are added, followed by the builder and any additional adjunct ingredients. If desired, polyphosphate can be used as an alkaline salt in the neutralization. The high shear mixing can take from one minute to one hour, with the usual mixing time being from about two to twenty minutes. Preferably, the batch temperature is from about 50°C to about 60°C. Examples of equipment which may be used for the high shear mixing include, the Sigma Mixer high sheer mixer, manufactured by Fabdecon Engineers, Bombay India; or a plough sheer mixer, manufactured by Littleford Day, Inc., Kentucky, U. S. A.

The blender mix is charged to a surge tank. The product is conveyed from the surge tank to the mill. As the mixture is being milled, the mixture is cooled to a temperature of from about 40°C to about 62°C. Preferably, the mixture is cooled by the running of cool water through the mill, which in turn cools the mixture being milled.

After milling or preliminary plodding after milling, 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.

The following examples further describe and demonstrate the preferred embodiments within the scope of the present invention. The examples are given solely for the purpose of illustration, and are not to be construed as limitations of the present invention since many variations thereof are possible without departing from its spirit and scope.

Example 1 This example shows a soap laundry bar composition: Component % by Weight NaLAS 10 ADMOX SC-1485 (amine oxide) 2.5 Soap 40 Sodium Tripolyphosphate (STPP) 5 Coco Fatty Alcool Substituted Methyl Cellulose 0.5 Fluorescent Whitening Agents 0.10 Perfume 0.15 Moisture 23 Other conventional ingredients. balance to 100 Example 2 This example shows a synthetic and soap laundry detergent bar: Component % by Weight NaLAS 10 Soap 40 Soda Ash 6 Water 30 Fluorescent Whitening Agent 0.15 Bluing Agent 0.004 Substituted Methyl Cellulose 1 ADMOXSC-1485 1 Talc 18 Perfume 0.26 Other conventional ingredients balance to 100 The aspects and embodiments of the present invention set forth in this document have many advantages, including improved physical properties

versus laundry detergent bars comprising alternate ranges of amine oxide, soap and LAS. Such improved physical properties may include, improved homogeneity, reduced softness, easier processing, easier packing and shipping of resulting product, and better economy in use.

Such compositions also have improved performance properties including improved cleaning, whitening, oily/greasy soil removal, sudsing in hard water, calcium tolerance, and/or mildness to the user's hands, versus other levels of the same components in a laundry detergent bar composition It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to one skilled in the art without departing from the scope of the present invention.